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Publication numberUS3112530 A
Publication typeGrant
Publication dateDec 3, 1963
Filing dateDec 29, 1960
Priority dateJun 28, 1956
Publication numberUS 3112530 A, US 3112530A, US-A-3112530, US3112530 A, US3112530A
InventorsBoggs Herbert D, Magoon Jr Fred L
Original AssigneeH D Boggs Company Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Pipe casting apparatus
US 3112530 A
Abstract  available in
Images(9)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Dec. 3, 1963 9 Sheets-Shet 1 Original Filed June 28, 1956 mam-0R3 f erzeri'fl .3009 S Halal/ 9004 BY: z Z I AIT RN YS 1963 H. D. 80668 ETAL 3,112,530

PIPE CASTING APPARATUS MM QWW ATTORNEY.

. 3, 1963 H. D. BOGGS E.TAL

PIPE CASTING APPARATUS Original Filed June 28 1956 9 Sheets-Sheet 3 H. D. BOGGS ETAL 3, ,5 0

PIPE CASTING APPARATUS 9 Sheets-Sheet 5 INVENTORS llll |||l l o s F-eJL/Vgoif/r ATTORNEYS Dec. 3, 1963 Original Filed June 28, 1956 g. will BYWQM6MW 3 ml 3w H. D. BOGGS ETAL PIPE CASTING APPARATUS Dec. 3, 1963 Original Filed June 28, 1956 9 Sheets-Sheet 6 ATTORNEYS Dec. 3, 1963 H. D. BOGGS ETAL 3,112,530

' PIPE CASTING APPARATUS Original Filed June 28, 1956 9 Sheets-Sheeb 7 FIG. 12.

A Mm! I flerlerfp-flgfs A EeJL/Vifo Jr wwpa pmw ATTORNEY H. D. BOGGS ETAL PIPE CASTING APPARATUS Original Filed June 28, 1956 Dec. 3, 1963 9 Sheets-Sheet 8 INVENTORSI fi er-51275.0. B fled L; Ma gtoondr:

CNN

United States Patent 3,112,539 PIPE CAS'IING APPARATUS Herbert l Eoggs, Erea, Calif., and Fred L. Magoon, Zia, Longview, Tern, assignors, by mesne assignments, to H. Eoggs Eompany, Ltd, Gmaha, Nelm, a limited partnership Qriginal application .lnne 28, 1956, Ser. No. 594,565, new Patent No. 2,997,737, dated Aug. 29, 1961. Bivided and this application Dec. 29, 196i Ser. No. 79,297

6 Elaims. (ill. 13-2-5) This invention relates to methods and apparatus for the manufacture of plastic pipe, and, more particularly, of centrifugally cast plastic pipe which is reinforced by Woven glass filaments.

The arts concerning the manufacture of fibrously reinforced plastic pip'mg and, more specifically, piping formed from thermosetting plastic materim, such as thermosetting resins, and reinforced with various fibrous elements, and more specifically with fibrous elements formed of glass filament formations, have been extensively disclosed and discussed in detail in the copending applications of H. D. Boggs, Serial No. 200,193, filed December 11, 1950, now Patent No. 2,776,450, issued January 8, 1957, Serial No. 264,976, filed January 4, 1952, now Patent No. 2,785,442, issued March 19, 1957, and Serial No. 459,092, filed September 29, 1954, now abandoned and in the following copending applications assigned to a common assignee: Kenneth A. Schafer, Serial No. 280,766, filed April 5, 1952, now abandoned and Lewis Perrault, Serial No. 404,329, filed January 15, 1954, now abandoned.

It is within the contemplation of this invention to prepare uniformly formed, fibrously reinforced, plastic piping of the type illustrated or discussed in some of these applications, as well as provide improvements in the apparatus and methods, for preparing such plastic pipe, described in others of these applications.

It is therefore an object or" this invention to provide new and improved means, and new and improved combinations of means, for manufacturing fibrously reinforced plastic pipe.

It is another object of this invention to provide new and improved apparatus for manufacturing fibrously reinforced plastic pipe which provides greater uniformity of product and better quality control.

It is another object of this invention to provide new and improved apparatus for manufacturing fibrously reinforced plastic pipe, which apparatus can be easily and continuously operated by a small labor force.

These and other objects of this invention will be fully understood from the following detailed description of a typical preferred form and application or the invention, throughout which description reference is made to the accompanying drawings in which:

FIGURE 1 is an elevational view, with portions broken away, to show details of interior construction of a mandrel assembly;

FIGURE 2 is an end view of the mandrel taken along lines 2-2 of FIGURE 1;

FIGURE 3 is a section taken along lines 3-3 of FIG- URE 1;

FIGURE 4 is an elevational view of the braiding and cleaning apparatus;

FIGURE 5 is an elevational view of the mold-feeding assembly;

3,1 E2536 Patented Dec. 3, 1963 FIGURE 6 is a plan view of the mold-feeding assemy;

FIGURE 7 is an elevational view, partially in section, illustrating details of the means for locking the moldfeeding assembly in position;

FIGURE 8 is a section taken along lines 83 of FIG- URE 6;

FIGURE 9 is a vertical sectional view of a collar;

FIGURE 10 is a section taken along lines 1t 10 of FIGURE 9;

FIGURE 11 is a vertical sectional view of the collar illustrated in FIGURES 9 and 10 being threaded into position at the mold end of the mold-feeding assembly;

FIGURE 12 is an elevational View, partially in section, of the mold assembly;

FIGURE 13 is an elevational view, with portions broken away to illustrate interior details, of the resin impregnating means;

FIGURE 14 is a plan view of the air-blowing assembly;

FIGURE 15 is an elevational View of the air-blowing assembly;

FIGURE 16 is an end view bly;

FIGURE 17 is a schematic diagram of the air pressure system used in energizing the air-blowing assembly;

FIGURE 18 is an elevational view of the pipe-ejecting assembly;

FIGURE 19 is a sembly; I

FIGURE 20 is a section taken along lines 2il20 of FIGURE 19; and,

FIGURE 21 is a section taken along lines 21-21 of FIGUREZO.

of the air-blowing assemplan view of the pipe-ejecting as- General Description Before making a detailed disclosure of the apparatus and methods for forming plastic pipe which constitute this invention, a general description will be presented.

The apparatus of this invention includes a mandrel assembly upon which reinforcement elements in the form of concentric sleeves or tubes of glass fiber are woven or braided by conventional braiding apparatus. The mandrel assembly consists of a cylindrical mandrel core enclosed within a cylindrical mandrel sleeve, the latter being separated into several longitudinally extending segments. A plurality of fibrous tubes are braided in concentric layers on the exterior of the assembled mandrel, with each of the fibrous tubes being subjected to a heat cleantreatment prior to being circumscribed by the next tube. Each mandrel assembly has a length equal to a length of the sections of the pipe to be formed and is arranged to smoothly abut, in tandem relation, against another mandrel assembly to form, in effect, a continuous mandrel, so that the braiding machines form continuous lengths of concentric fibrous tubes which are subsequently cut oil in lengths approximating that of each individual mandrel assembly.

In other words, after the concentric fibrous reinforcement elements have been formed upon the tandemly arranged mandrels, the mandrels are separated with the reinforcement elements being cut at the points of separation. Thereafter each mandrel, which is circumscribed by a reinforcement element consisting of two or more concentric Woven fibrous sleeves or tubes, is placed on a moldfeeding assembly, which serves a plurality of pipe casting molds. The mold-feeding assembly is aligned with,

and selectively positioned relative to, a selected mold and then mechanisms thereon are operated to insert the mandrel assembly, together with the Woven reinforcement element, into the mold. Other mechanisms on the moldfeeding assembly are then operated to withdraw the core of the mandrel assembly from the mold, leaving a major portion of the mandrel sleeve, together with the fibrous reinforcement element, therewithin. The remaining elements or segments of the mandrel sleeve are then removed by hand, or by other means, to leave the Woven fibrous reinforcement element smoothly disposed against the inner periphery of the cylindrical casting mold.

This invention also includes means for introducing heat settable material, such as thermosetting resins and the like, through the ends of the molds and uniformly along the entire length of the interiors thereof in a manner which will not disturb the placement of the individual fibers of the woven fibrous reinforcement element disposed therewithin.

This invention further includes means for centrifugally casting plastic impregnated fibrously reinforced piping by providing means for concurrently heating and rotating the mold, as well as for concurrently cooling and rotating the mold.

It is also within the contemplation of this invention to provide means for uniformly heating the contents of the mold, prior to the heat setting of the thermosetting material, by blowing heated air through alternating ends of the mold.

It is also Within the contemplation of this invention to provide means for uniformly cooling newly formed plastic impregnated, fibrously reinforced pipe while it is undergoing an exothermic reaction within the mold, just after it has been heat set into its final physical form, by blowing air through the alternating ends of the mold.

There is a pipe ejecting assembly, arranged to serve a plurality of the casting molds, which is aligned with a mold in which the plastic pipe has been formed, and which carries mechanisms thereon to withdraw the newly formed plastic pipe from the molds in a manner which eliminates any danger of damage to the pipe.

For the sake of clarity, the various apparatus and means briefly described hereinabove will be separately described and illustrated.

The Mandrel Assembly Referring to FIGURE 1, the mandrel assembly, generally indicated at 9, includes a mandrel core which is formed of cylindrical stock and may be hollow to save material and avoid excessive weight. One end of the mandrel core 10 has a cylindrical projection 12 of reduced diameter, and the other end is formed to define a cylindrical socket 14, which is dimensioned to snugly, but slidably, receive a projection 12 from another identical mandrel. The bottom or end wall 16 of the socket 14 has a centrally located threaded aperture 18 therein, although if the mandrel core 14 is formed of solid stock, the aperture will be replaced by a similarly located threaded socket.

The free end of the projection 12 may be beveled, as at 2.6, and the mouth of socket 14 may be beveled, as at 22, to facilitate the entrance of a projection into the socket. Similarly, the mouth of the aperture 13 may be beveled, as at 26, to aid in the reception of either a projection 12 of another similar mandrel or a member which will be described hereinafter. It should be noted that the axial length of each projection 12 is somewhat greater than the depth, or axial length of each socket 14, the difference in length being substantially equal to the axial length of a collar, generally indicated at 24, formed by the end portions of the slips 27, 28, 29, and 3t (FIGURES 2 and 3), which will now be described.

Each mandrel is provided with a plurality of, and in a preferred embodiment four, slips 2'], 28, 29, 3d. The slips 2'7, 28, 29 and 30 are formed of relatively thin lengths of metal, each having an arcuate cross section, and the slips of a given mandrel, when properly arranged together, form a cylindrical sleeve which encloses the exterior periphery of the mandrel core 10 and which extends the entire length thereof. Each of the slips has a shoulder 32 welded, or formed, thereon to extend radially inward, relative to the arcuate curvature of a section thereof. The free end of each of the shoulders 32 is arcuately curved, about the same center as the arcuate curve of its slip, so that the combination of the shoulders of all of the slips 2?, 28, 29 and 3t fitted on a given mandrel core 10 form an inwardly extending, circumferential collar, generally indicated at 24, on the sleeve formed thereby. Actually, as best shown in FIGURE 2, this circumferential collar is only approximated and is not complete because the radially-inwardly extending neighboring surfaces 25 of some of the shoulders 32 are not parallel, but rather diverge, by perhaps 30", as they extend inwardly. The approximated collar 24 has an interior diameter somewhat greater than the exterior diameter of the projection 12, and, as best shown in FIGURE 1, the thickness of the approximated collar 24, that is to say its axial length, is approximately equal to the difference between the length of the projection 12 and the depth, i.e., axial length, of the socket 1 3. It will therefore be seen that when identical mandrel cores 1%, each fitted with an enclosing sleeve formed by the slips 27, 28, 29 and 3%, are tandemly aligned, and then moved into axial abutment, the several mandrel assemblies 9 will form an essentially continuous mandrel having a substantially smooth and unbroken cylindrical exterior.

While in the illustrated preferred embodiment there are four slips 27, 23, 29 and 30, it is within the contemplation of this invention that there may be more or less. In any event, one of the slips 27, which is preferably small, i.e., narrow, is permanently afiixed, as by screws 36 (FIG- URE l), to the mandrel core it). The other slips are held in position by a circumferential tension spring 38, one or more of which may circumscribe the entire mandrel as sembly 9.

Referring to FIGURE 1, it will be seen that each shoulder 32 has a small pin 3? on the inner surface thereof, that is on the surface abutting the end surfaces of the mandrel core 1t}, and that the end surface of the core has a complementary socket to snugly receive this pin.

The Braiding and Cleaning Apparatus Referring to FIGURE 4, the tandemly aligned and axially abutting and interfitting mandrel assemblies 9 are fed, by hand or by any means, onto a power driven pinch roll standSf), which urges them through a series of alternating braiding and heat cleaning devices, generally indicated at 52 and 54, respectively. The braiding machines 52, which may be of any standard form and design, and which are merely outlined in FlGURE 4, are equipped with a number of braider heads 56, and in a preferred em bodiment with 96 braider heads, to weave glass filament threads 57 into a braided tube 58 about the mandrel assenr blies 9. In some cases the braiding machines will inelude means to lay a plurality of separate strands on the surface of the mandrel assembly to extend longitudinally thereof in peripherally spaced relationship, the braiding means and the last mentioned means being cooperatively arranged to braid the woven strands about the longitudinally extending strands. The braiding machines 52 and the pinch roll stand 5t) are all powered by a common drive shaft 5? so that there is a fixed relation between the speed of the rotation of the braider heads 56 about the lengths or" mandrel assemblies 9 and the axial movement of these. mandrel assemblies through the braiding machines. When, in accordance with this invention, successive layers or plys of the tubular reinforcement element, generally in-- dicated at 60, are desired, several braiding machines 52 are arranged in alignment to form successive plys upon the substantially continuous mandrel assemblies 9 passing therethrough, one such machine being provided for each.

ply. The mandrel is supported by rollers 61, one being located on each axial side of each braiding machine.

Standard glass filament threads which are currently available are manufactured and supplied to the industry with a coating, such as starch or oil, on the filaments to act as a lubricant during subsequent handling. It has been discovered that it is desirable to remove all such coatings from the filaments prior to the using of reinforcing elements formed therewith in the casting of fibrously reinforced plastic pipes with thermosetting resins, as such a coating serves to prevent, or at least retard, the forming of a satisfactory adhesion or bond between the resin and the glass fibers. For instance, it has been found that certain coatings will form air bubbles on the glass filaments during the curing of the resin. As has been explained in the copending application, Boggs application No. 459,092, filed September 29, 1954, now abandoned, a satisfactory bond between the resin and the individual fibers of the reinforcement element is essential if a sufiiiently strong, non-weeping, and pressure resistant pipe is to be formed.

It is therefore within the contemplation of this invention to remove such a coating by the provision of a heat cleaning device, generally indicated at 54, between each of the braiding heads. Due to the fact that glass is a good insulator, it is preferable to remove this coating, when present, after each ply is formed or braided on the mandrel and hence, to provide a separate cleaning oven 62 at the discharge side of each braiding machine. It has been found that due to the high heat conductivity of the metallic mandrel assembly 9, a higher oven temperature is required to remove the coating on the first layer or ply on the mandrel, than is required in the subsequent ovens because the second and subsequent plys are insulated from the mandrel by the first ply, or the inner plys. As a filament temperature of approximately 600- 850 F. is required to satisfactorily destroy the coating on the glass, it has been found that satisfactory results may be obtained when the temperature of the first oven, which heats the innermost ply, is in the range of 1500- 1800 F., and when the temperature of the successive ovens are in the range of 1500 P. All of the oven temeratures set forth are on the basis of the sleeve being braided, and hence, the continuous mandrel being moved, at a speed of 33 to 61 inches per minute, and it is believed that the oven temperature ranges may be varied to some degree, depending upon the speed of the mandrel, the length of the oven, the thickness of the braid, and the particular coating which is used upon the glass fibers being braided.

In a preferred embodiment of this invention, the heatcleaning device 54 consists of an elongated cylindrical chamber or oven 52 surrounding the axially moving mandrel assemblies 9 which are covered with one or more layers of braided glass fiber tubing 58. Each oven is connected by suitable ducts with a small furnace, preferably a gas furnace 63, which is supplied with gas and an excess of combustion air by compressor-mixer 64. The combustion products and the heated excess air travel to the oven 62 and thence to a collection ring 65 and out through vent 66. It should be recognized that the specific design of the furnace and oven can be considerably varied within the scope of this invention and that any other similar arrangement may be utilized to bring the temperature of the filaments of the tube 53, or filaments of the outside tube if there are more than one, up to a temperature of a range of 600 to 850 P. so that the coating of starch and oil on the glass fibers will carbonize. It has been found that once the starch and oil coating on the fibers has been carbonized, it no longer affects the bond between the glass and the resin, and, further, that the carbon acts satisfactorily as a filler in the pipe body. It will now be understood that it may be desirable to coat the outer surface of the mandrel assembly 9, i.e., the outer surface of the sl ps 2'7, 28, 23 and 30, with a silicone release agent,

5 such as a standard commercial high temperature silicone grease, by means of a felted brush 67, as it leaves the pinch roll 50, so that the innermost tube will not adhere to the mandrel assembly and thus hinder the subsequent removal thereof, in a manner which will be described in detail hereinafter.

It may be desirable to pro-clean the exterior of the mandrel assembly by means of a circumferential wire brush 67a which is formed to receive a belt drive 671: which is, in turn, rove over a spindle 67c, fitted on power shaft 59, so that the wire brush will be positively actuated to revolve about the mandrel assembly.

It Will now be understood the tension spring 38, which helps hold the slips 28, 29 and 30 on the mandrel core prior to the first braiding operation, must not be allowed to enter the braiding machines. A guard 67d is therefore fitted on the entry side of the pinch roll stand 50 to catch these springs.

After an individual mandrel has been passed through several braider heads and ovens, and has received the desired number of plys or layers of braided tubing, the continuous reinforcement element 60, consisting of the concentric fibrous tubes 58, is cut at the points of intersection of a given mandrel assembly 9 with its neighboring mandrel assemblies. The ends of the reinforcement element 60 are tied or taped to prevent the braid from unraveling and the mandrel assembly is then transported to the mold-feeding assembly.

The Mold-Feeding Assembly Referring to FIGURES 5 and 6, it will be seen that a mold-feeding assembly, generally indicated at 68, includes an elongated base frame, generally indicated at '70, which is mounted on flanged Wheels 72 for movement along relatively transversely extending fixed rails 74 so that the entire mold-feeding assembly can be transversely moved between a number of positions corresponding to a number of casting molds, generally indicated at 76. In a preferred embodiment, the transverse movement of the entire moldfeeding assembly 6% is selectively controlled by a hand operated sprocket wheel 78 which is connected by a chain drive $0 to a sprocket 82 on the shaft 84, upon which the wheels 72 are non-rotatably mounted. As will be evident hereinafter, it is quite important that the entire moldfeeding assembly 68 be properly aligned with the axis of the particular mold which it is to service and the means for attaining this exact alignment will now be described.

Depending from the mold-feeding assembly base frame 7% is an airlock assem ly, generally indicated at 86 (FIG- URES 5 and 7), consisting of a pneumatic cylinder 88 having a piston rod 9d extending therefrom, with the entire assembly being so located that when the piston rod 9%} is being pneumatically urged outward, it bears against the web 92 of one of the fixed rails 74. The web 92 of this rail 74 has one aperture 94 drilled therein, or a recess formed therein, at the same level as the piston rod 90, for every mold 76 which is to be served. The aperture 94 is dimensioned to receive the piston rod 90, in a manner to lock the entire mold-feeding assembly 68 against further transverse movement, and is so transversely (of the mold-feeding assembly 68) located as to receive the piston rod when the entire mold-feeding assembly is properly aligned with a given mold. The air lock assembly may be remotely controlled, by a valve 96 located near the sprocket Wheel 78 (FIGURES 5 and 6), to urge the piston rod outwardly, or towards an extended position, when it is intended to lock the mold-feeding'assembly 68 in a desired position, that is to say in alignment with a particular mold, and also to urge the piston rod to a retracted position, clear of the apertures 94, when it is desired to unlock the mold-feeding assembly before moving it to a new position.

Referring again to FIGURES 5 and 6, the transversely movable base frame 70, which consists essentially of a pair of suitably braced, longitudinally extending, spaced parallel rails lltltl, which may be formed of l-beams or the like, has a second frame, generally indicated at 192, which consists essentially of a pair of suitably braced, longitudinally extending, spaced parallel rails 1%, which may be formed of l-beams or the like, mounted thereon. The second frame 162 is supported on flange wheels 1&6 which are arranged to roll along rails 103 when the second frame is moved longitudinally of the base frame 7G. Such movement is obtained by a pneumatic cylinder 1%, depending from the second frame 1G2, having the free end of its piston rod lit fixed to a fixed upstanding member 112 on the base frame 7%. The pneumatic cylinder 1% is double acting and is coupled, by suitable lines, to a three-Way control valve 114 located on the operating panel 115.

A mold-feeding carriage, generally indicated at 116, is disposed upon the rails 3.94 to move longitudinally thereof on wheels 1153. The mold-feeding carriage 116 is positively actuated to move longitudinally of second frame 162 by a chain drive 12% extending longitudinally of the rails 13d, and approximately midway therebetween, at a level slightly below their upper surface. The chain drive 12a? is secured, at each end, to the mold-feeding carriage 136, as by draw bolts 122 (FIGURE 8), and extends around an idler sprocket 12 i mounted at the mold end of the rails 1% and around a power sprocket 125 mounted at the opposite end of these rails. The power sprocket 125 is non-rotatably fixed to a coaxial drive sprocket 126 which is, in turn, engaged by chain drive 128 to a sprocket 13ft fixed on the shaft of reversible air motor 132, the latter being remotely controlled by a three-way valve 134 located on the operating panel 115.

As the mold-feeding carriage lid serves to convey an individual mandrel assembly circumscribed by a reinforcement element so, consisting of one or more layers or plys of braided tubing, into a waiting casting mold '76 and, further, to withdraw a mandrel core ll) from a mold, there are provided several mandrel supporting rollers 136 to bear the weight of the mandrel during the periods when it is on, or partially on, the mold-feeding assembly 68.

Referring more particularly to FIGURE 8, cantilevered from the mold-feeding carriage 116 is a tube 138 of heavy stock extending toward the mold end of the rails 104. The tube 138 has an exterior diameter substantially equal to the exterior diameter of the mandrel core 10, and the free end thereof is formed with a projection 14-6" of reduced exterior diameter which is dimensioned to fit into the socket 14 of the mandrel core. Loosely fitted within the tube 138 is a mandrel engaging shaft 142 having a threaded end 141 which normally extends outwardly from the reduced end 140 of the tube, that, is, the end towards the casting molds '76. This threaded end 141 is so dimensioned that its threads will operatively engage the threaded aperture 18 in the bottom or end of socket M. The opposite end of the mandrel engaging shaft 142 extends without the opposite end of tube 138 and has a hand wheel 143 fitted thereto.

A collar 144 having an internal diameter slightly greater than the exterior diameter of the mandrel core its, and somewhat smaller than the exterior diameter of the assembled slips 27, 23, 29 and Si is loosely fitted on the mold end of the tube 138. As shown in FlG- URES 9 and 10, the collar 1 34- is formed with a longitudinally extending keyway 146 which has a width and depth slightly greater than the width and height of fixed slip 27. That is to say, the collar interior, including its keyway 146, is so dimensioned as to allow the mandrel core 1%, together with the fixed slip 27, to move therethrough when the keyway is properly'indexed with the fixed slip. The end of the collar located nearest the mold '76 has a short counterbore dimensioned to receive the entire mandrel assembly 9, the counterband defining a para-annular abutment 45, the annulus defined by the abutment being broken by key'way 1%. The exterior of threads 147 of the collar.

the collar has a few turns of raised heavy-duty threads 14'] formed thereon on the end furthest from the mold '76 for reasons which will be apparent hereinbelow. The exterior of tube 133 has a key 14% mounted thereon to fit into keyway 146 to prevent relative rotation between the collar 14 i and the tube 138.

in operation, the entire mold-feeding assembly 68 is aligned with the particular mold 76 to be supplied with a reinforcement element as and the second frame is correctly positioned, longitudinally of the base frame, in a manner which will become evident hereinafter. A mandrel assembly 9, which has been passed through the alternating braiding machines 52 and heat cleaning ovens 54, and which has reinforcement element 60, consisting of a number of concentric braided fibrous tubes, formed thereon, is placed upon the mandrel supporting rollers 1355, with the end having the recess 14 facing the moldfeeding carriage 116, which is then disposed at the ends of the rails 104 which are furthest from the mold 76. The mandrel assembly is so indexed that the fixed slip Z7 is angularly aligned with the keyway 1% of the collar 144. The mold-feeding carriage 116 is then moved, by air motor 13-2., toward the mold 75 to a position wherein the reduced end of the tube 138 fits within the recess 14 of the mandrel core it). The threaded end 141 of shaft 142 will then be abutting and engaging the first turn of the threads of aperture 13. The shaft 14-2 is then rotated, by means of hand wheel 143, to eifect a firm threaded engagement between the shaft 142 ad the mandrel core ill. The mold-feeding carriage 116, to-

gether with the mandrel assembly 9 affixed thereto, and the collar 144 mounted thereon, is then moved, by air motor 132, toward the mouth of the mold 76 until the mandrel assembly and its surrounding reinforcement element 69 are entirely within the mold 76.

Referring more particularly to FIGURE 11, as the mandrel assembly 9 moves toward the mold 76, the end thereof opposite firom the mold-feeding carriage 116 passes through the aperture of a large out 149' which is mounted for rotation about a fixed axis, corresponding to the axes of the mandrel assembly 9, the tube 138, the collar 14-4, and the mold 76, by the loose fit of its radially extending, circumferential flange 150 within a correspondmg annular groove 152, formed by a flanged angular ring 154 and an apertured plate 156, the latter member being mounted on, and fixed to, the mold ends of rails 104. The nut 149 has a portion of its exterior periphery formed as a sprocket wheel 157 which is engaged, by a chain drive 158, with a drive sprocket 160 (FIGURE 6), the latter being operated by a coaxial hand wheel 161 which is located at the operating panel 115.

The threads of nut 149 are dimensioned for engagement with raised threads 147 of the collar 144. After the mandrel assembly 9 is completely within the mold 76, the collar 144- is moved axially, by hand, or other means, along the tube 138 until it extends through the nut 149' and its mold and almost touches the slips 27, 28, 29 and 30. It will now be understood that if the second frame 102 has been correctly longitudinally positinned along the rails 100 of the base frame 76, the distance between the mold end of the collar 144 and the slips will be the thickness, i.e., the axial length, of the Stated otherwise, the correct position of the second frame 102 will be determined by the length of the collar 144-.

At this time the collar M4 is so indexed that its longitudinally extending interior keyway 146 is angularly aligned with the small slip 27 which is permanently secured to the mandrel core 10. Hand wheel 162 is then operated to rotate the nut 149 and threadably engage the collar 144 therewith. As the collar engages the nut, its

.mold end moves axially to bear against the slips 23, 29

and 3t), but not against slip 27, as this member is aligned With the keyway I l- 6. It will be readily seen that after 9 this is done, the cells 34-4 is lined against axial movement relative to the mold '76- and the trails 164.

In FIGURE 11 the collar 144 is illustrated as approaching, but not having yet reached, its final position of abutment with the slips 2%, 29' and 3%. It will be noticed that further appropriate rotation of the nut 149 will move the collar 14 closer to the mandrel assembly 9, that is, until the para-annular abutment 145 is fast against the slips 2%, 29 and 349. Then the collar will be unable to move further unless the second frame 16-2 is moved away from the mold assembly '76. It should be noted that when the collar is so abutting the mandrel assembly ll), the end of the collar, in the area of the counterbore, will extend a short distance into the space between the exterior of the mandrel assembly lit and the interior of the mold 76. The reinforcement element formation 61 will necessarily be distorted and compressed by this, but only along the small portion immediately affected and, as will be evident hereinafter, this distortion is only temporary and the reinforcement element will usually spring back to its ordinary position after the collar 144 is removed from the area.

As has been described hereinabove, the interior diameter of the collar 14-4 is slightly greater than the exterior diameter of the mandrel core 1%, and it will therefore be seen that when, in accordance with this invention, the mold-feeding carriage 116 is moved along rails 1&4, by air motor 132, away from the mold 76, the mandrel core it), together with the fixed slip '27, will then be withdrawn from the immobile mold, through the lumen of the immobile collar, while the slips 2%, 29 and 39* are held fast in their position within the mold because of their abutting relation with para-annular shoulder 145 of the collar.

The means for supporting the mandrel assembly 9 prior to its insertion within the mold 76 and the means for supporting the mandrel core it after its withdrawal from the mold will now be described. Referring to FIGURES and 6, the mandrel support rollers 13d are, when in their operative position, located midway between rails 194 and at a level slightly below the upper surface thereof. Each set of rollers 136 consists of an opposed pair of spaced coaxial truncated-conical rollers having their minor ends facing one another. As is best shown in FIGURE 5, when the mandrel support rollers 136 are operatively positioned at a level to support a mandrel assembly, and particularly a mandrel assembly of relatively small diameter, they will necessarily be located within the longitudinal path of the mold-feeding carriage 116. It is therefore within the contemplation of this invention to provide means for moving the mandrel support rollers 136 from then usual position when the mold-feeding carriage passes by.

To effect this end, each of the rollers 13o are rotatably mounted at the free end of one of two roc 'er arms 169 which extend, in spaced parallel relation, radically out- "ard from a rocker arm shaft 171 which is rotatably mounted in suitable bearin s (not shown) to extend under, and transversely of, the rails 1%.

An operating arm 175 is fixed to rocker arm shaft 171 and eXtends radially therefrom. In the preferred embodiment illustrated this operating arm is an-gularly displaced from the rocker arms 169, and is pivotally connected to a drive rod 179 which is, in turn, pivotally connected with a piston rod 131 of pneumatic cylinder 133. The pneumatic cylinders 183 may be selectively operated from the operating panel 115 at such times as the mold-feeding carriage 116 approaches a given set of mandrel supporting rollers 136, or, as in this preferred embodiment, this operation may be entirely automatic by the provision of suitable mechanically operated valves (not shown), such as are well known in the art and need not be defined or described in detail herein, which energize the pneumatic cylinders to lower a particular set of rollers 136 as the mold-feeding carriage approaches.

It should be noted that the opposed trunca ed ends of the mandrel support rollers 136 are spaced from one another a distance sufiicient to allow clearance of the drive chain when the opposed rollers move downward, as a unit, through an arc defined by the movement of the rocker arms 169. While the preferred embodiment illustrated in FIGURES -5 and 6 has two sets of mandrel support rollers 136, it should be understood that it may be desirable to provide additional sets of rollers, particularly when the pipe to be cast, and hence the mandrel assemblies 9, are unusually long. In such a case, each set of mandrel support rollers would be provided with means for lowering the rollers below the path of the passing mold-feeding carriage 116 which are simi lar to the means which has just been described.

After the mandrel core 10 has been wholly withdrawn from the mold 76, hand wheel 143 is manipulated to release the thread 141 from the threaded aperture 18 of the mandrel core so that the latter can then be removed. At this time the second frame 192 is moved longitudinally, of the base frame 7i); away from the mold 7 6 a sufficient distance to provide ample clearance between the end of the mold and the collar 14-4, and the latter is released from the nut 149 and placed in its original position on the tube 138. This may be done by hand or, in the alternative, the mold-feeding carriage 116 can be moved forwardly, or in the direction of the molds '76, so that the tube 138 extends through the collar 144, and is keyed thereto, before the latter is disengaged from the nut 149 by suitable manipulation of hand wheel 161.

When the mandrel core 19', together with the fixed slip Z7, is removed from the mold 76, the pins 39' of the remaining slips, i.e., slips 28, 29 and 30, are, in effect, withdrawn from their respective sockets in the mandrel core. As they no longer form a complete tube or sleeve, they will then collapse and fall to the bottom of the interior of the mold. After the second frame 102 is longitudinally moved away from the mouth of the mold, and either before or after the collar 144 is disengaged from tr e nut 149, the entire mold-feeding assembly is moved transversely, by suitable manipulation of operating wheel 78, to a position where it is clear of the mouth of the mold. The slips 28, 29 and I are then removed, either by hand or suitable power machinery (not shown), from the mold.

As will be readily understood, in withdrawing the individual slips from the mold, care should be exercised lest the fibers of the reinforcement element 6ft be disturbed and disarranged from their normal positions. As has been explained in the copending applications hereinabove mentioned, the quality and strength, and hence the end performance, of fibrously reinforced plastic pipe is quite dependent of the accuracy and precision of placement of the fibers of the reinforcing element. It will now be seen that the use of the mandrel assembly 9 in the particular manner described hereinabove constitutes a marked improvement over the previously known apparatus and methods of inserting woven tubular reinforcement elements within a mold, inasmuch as it makes it unnecessary to slide a mandrel against the interior of the close-fitting innermost ply or layer of the reinforcement element 60. it has been found that when an ordinary mandrel is used, it frequently occurs that the Weight of the mandrel on the lower portion of the reinforcement element causes the latter to bunch, and thus reduces the inside diameter of the element until it finally seizes the mandrel, particularly when the mold is quite long. Even if the mandrel is not seized, the bunching of the reinforcement element distorts the arrangement of the fibers so that they are no longer disposed in the desired patterns, and a plastic impregnated pipe formed there-with may be materially weakened.

The Mold Assembly It is within the contemplation of this invention that there be provided a number of molds, generally indicated at 76, arranged in aligned rows to be serviced by the moldfeeding assembly 68, which has been already described, and which will also be serviced by a single mold-ejecting assembly 268 (FEGURES 18, 19 and 20), which will be described in detail hereinafter. 7

Referring to FIGURE 12, in each mold assembly 76 there is, an elongated tubular casting mold 162 ro-tatably supported by ball bearings 153, or other conventional low friction means, within the lumen of a fixed tubular heating chamber 164-. The end of the mold 162 opposite to the end which receives the mandrel assembly is counterbored, at 165, and interiorly fitted with an annular collar 166, which is exteriorly dimensioned to fit into the counterbore, and has an interior diameter equal to the bore of the mold. if the pipe to be cast is to have one end exter-iorly threaded, the collar 166 may have a threaded interior so as to act as a thread mold. The ends of the mold 162 extend a short distance beyond the ends of the heating chamber 164 so that, during the casting operation, the mold can be partially closed by externally threaded caps 167, each having a centrally disposed aperture 168 therein. At or near the ends of the heating chamber 164, O-ring liquid seals 17% engage the outer periphery of the mold 162 and the inner periphery of the chamber so that the lumen of the heating chamber is liquid tight even when the mold is being rotated in a manner which will now be described.

At one end of the mold 162, and in a preferred embodiment at the mouth or the end which receives the loaded mandrel, a V-belt pulley 172 .is non-rotatably fixed, by bolts 173, to the mold coaxially therewith. This V-belt pulley is engaged, by a number of V-belts 174, to a suitable drive wheel 176 on the shaft of a prime mover 178, which may be mounted above the heating chamber. A portion of the junction of the V-belt pulley 172 and the exterior of the mold 162 defines an annular recess 180 having its female arcuate surface threaded to engage the exteriorly threaded cap 166 which partially closes the mouth of the mold. The other cap 166, fitted at the other end of the mold 162, engages a similarly threaded recess 182 formed in the built-up end of the mold.

Each heating chamber 164 is provided with one or more heating fluid inlets 184 and outlets 186 so as to allow a carefully controlled circulation of heated fluid, which preferably is oil, from a fluid heat exchanger 188. The heat exchanger 138' may be of any conventional design and will not be described in detail, it being enough to say the heat exchanger is designed and arranged to retain a relatively large amount of heating fluid at a carefully controlled temperature level so that there is always a sufficient supply of heating fluid available at the exact temperature desired. in the centrifugal casting of reinforced plastic impregnated pipe, it has been found that exact temperature control is often critical and this end can only be achieved by maintaining an adequate supply of fluid, at the proper temperature, available at all times. While the fluid is hereinabove termed a heating fluid, it should be observed that during the time of the exothermic reaction of the plastic pipe eing formed in the mold, the mold temperature may temporarily increase to a point whereby the fluid becomes a cooling fluid, i.e., the mold temperature may rise above that of the fluid.

The proper temperature of the heating fluid will vary from 150 to 350 F., depending on the character of the resin being used. When working with certain resins, it

may be desirable to pump heating fluid out of the heating chamber 164- after the resin has begun its thermosetting reaction, and replace it with a cooling fluid, also preferably oil, to carry off the exothermic heat generated. Also, as certain epoxy resins must be cured at a fairly high temperature, i.e., approximately 320 F., it may be desirable to use other means than air cooling (which will be described hereinafter) to get the temperature of the formed plastic pipe down to a point where the pipe is strong enough to be removed from the mold 162.

sumps, meters, and temperature indicia means which may be of conventional design well known in the art and which, therefore, need not be illustrated or desscribed in detail.

As the preferred heating and cooling fluids are oil, this fluid serves to lubricate, as well as control the temperature of, ball bearings 163, and, in such a case, no other lubrication is needed.

The Resin lmpregnating Means As shown in FIGURES l2 and 13, adjacent each end of the mold assembly 76 there is a resin reservoir 200 which is preferably large enough to contain suflicient resin for preparing a large number of plastic pipes. The reservoir Zilll is mounted above the level of the mold assembly, so as not to interfere with other moving elements in the vicinity and, in a preferred embodiment, is suspended from the ceiling structure (not shown). The reservoir may be a vessel of any conventional design, although it should have a large removable cover 292 to allow easy access for cleaning and loading and should include heating coils 294 for maintaining the liquid resin at a predetermined temperature so as to control the viscosity thereof. Compressed air is supplied to the top of each reservoir by conduit 205, so that liquid resin may be forced out under pressure through flexible conduit 266 to nozzle 208. The nozzles may have selectively variable openings, but it is within the contemplation of this invention that they be given a constant fitting or opening for use with resin of a given viscosity and in conjunction with a mold 162 of a given length.

After the reinforcement element 60 has been properly placed in the mold by the apparatus and methods described hereinabove, the nozzles 208 are inserted into the apertures 163 in the mold caps 167 (FIGURES l2 and 13) and the resin is then injected into the mold, by the operation of an air conduit control valve 210. With the proper combination of air pressure, resin viscosity, and nozzle opening, some of the air-borne stream of resin from each nozzle will reach a point half way through the mold.

In a preferred embodiment of the invention, the resin is introduced into the mold 162 while the latter is rotating at a high rate of speed, derived from the energization from the prime mover 178 (FIGURE 12). For example, in the manufacture of 3 inch O.D. pipe, it has been found that the mold should be rotated at approxirnately 1800 r.p.m., although it will be understood that when the larger pipes are being cast, the same centrifugal forces may be obtained at a lower r.p.m. As the mold rotates, and the liquid plastic material is being centrifug-ally urged to distribute itself evenly along the internal periphery of the mold 162, and hence, within and about the fibrous formations of the reinforcementelement 60, the heat of the heating fluid within the chamber 164 (FIG- URE 12), which surrounds the major part of the mold 162, causes a thermosetting reaction of the resin. It is well known that this thermosetting reaction will, in due course, be accompanied by a certain exothermic reaction on the part of the resin as it becomes set in its final physical form. While the heating fluid will serve to carry ofi a certain amount of this exothermic heat, it is within this contemplation to provide additional means for achieving this end, as it is not possible to remove the formed pipe from the mold until its temperature has been reduced to a vicinity of 129 F., and, further, as

this exothermic heat may, in some circumstances, have a deleterious efiect on the pipe being formed.

Air Blowing Assembly It is within the contemplation of this invention to provide each mold assembly 76 with an air blowing assembly, generally indicated at 221' (FiGURES 14, and 16), which is arranged to blow air alternately through one end of mold 162 and then through the other. It has been found that a greater uniformity of product is effected by alternating the direction of air flow so that all areas of the newly formed, fibrously reinforced plastic piping are more uniformly treated.

Each air blowing assembly includes a blower 222 operated by a prime mover 224 through a variable speed belt and pulley apparatus, generally indicated at 226. The blower 222 discharges into an upwardly extending duct 22 8 which splits, at a Y connection 230 into two branches, each of which extend to the respective ends of the mold assembly (shown in phantom) at '76.

As each branch is substantially identical, only one will be described in detail. The ends of each of the arms of the Y ducts 23% are fitted with a disc valve 232 which discharges into a horizontally extending duet 234. Duct 234 is fitted to the disc valve 232 by a suitable sleeve connection which allows this duct to rotate freely, about its own axis, which the valve remains immobile, and is also supported by a bearing 236 located in spaced relation to the valve. Another duct 2-38 is connected to the free end of duct 23d to extend generally downward and thence back towards the center of the air blowing assembly, and terminates in a mouth 24%) which is dimensioned to approximate the aperture in the cap 16-7 of the molding assembly 76, the last mentioned elements being shown in the phantom. The entire air blowing as sembly 229 is so dimensioned that the mouths 240 of each branch are spaced apart a distance only slightly greater than that of the overall length of the mold assembly 76.

As best shown in FIGURE 14, the air blowing assembly is placed to one side of the mold assembly 76, and when the downwardly extending duct 238 hangs in a plumb line, its month 246 is well clear of the mouth of the mold, so as not to interfere with the loading or unloading thereof.

The rotatably mounted duct 234- has a radially extending operating arm 241 fixed thereto, and the free end of this arm is connected to the vertically extending piston rod 242 of pneumatic cylinder 24 3, the latter being pivotally mounted on the base of the air blowing assembly. As is evident in FIGURES 14, 15 and 16, extension and retraction of the piston rod 2 2 will cause duct 23-; to oscillate about its own axis, and, further, will cause the duct 238 to swing from a plumb position to an oblique position (illustrated in phantom in FIGURE 16) and then back to plumb. The various elements are so dimensioned and arranged that upon a full extension of piston rod 24-2, the mouth 24% or" the duct 25% will be aligned with,

adjacent to, the aperture in mold cap 167.

The disc valve 232 is of conventional design and is operated by rotating an internal disc, having an off-center aperture 245 (in phantom, FIGURE 16), into and out of a position wherein the aperture is aligned with coaxial intfie 24s and discharge 24 7 fittings (FIGURES l4 and 15). In the present apparatus, the disc is caused to rotate about its axis by the arcuate movement of a pin 248 extending outwardly from the valve 232 on the same side as the operating arm 241. The pin 248 extends into an elongated slot 256 formed in the operating arm 2 so that it moves therewith. It will therefore be seen that the swinging of the duct 234 into a position whereby its mouth 24% is aligned with the cap 167 of the mold assembly 75 will also eliect an opening of the disc valve 232, and that when the duct 23% is moved back to a plumb position, the valve will close.

it is within the contemplation of this invention to ar- 14 range a system of timer-cam operated valves to supply pressurized air alternatively to one pneumatic cylinder 244 and then to the other in a timed cycle, of say one minute, so that each of the ducts 23S will alternatively swing into alignment with its end of the mold assembly 76 and then deliver a one minute blast of air while the other duct 238 is maintained in a position clear of the mouth of its end of the mold. It is further within the contemplation of this invention that there be provi e a manually operated bleeding valve to allow both arms to swing to a plumb position, with each disc valve 232 being closed, when the mold assembly 76 is being loaded or unloaded, or is not in use.

Such a system is shown schematically in FIGURE 17, in which timer 252 alternatively opens valves 25-4 leading to the respective pneumatic cylinders 244. The manually operated bleeding valves 256 are interposed in the pressure lines intermediate the valves 254 and the pneumatic cylinders 244. It should, of course, be understood mat the overriding valves 256 could also be connected with timing apparatus if the loading and unloading operations are to be part of a timed cycle.

While the thermosetting reaction of the material within the mold has been heretofore described as occurring as a result of the temperature of the heating fluid in the heating chamber 164, it is within the contemplation oi this invention that the air blown through the mold 162 may be heated when certain resins are being used in the casting operation. Accordingly, electric heating coils 26% (FIGURE 16), or other air heating means, may be installed at the intake of the blower 222 so that the air supplied to the interior of the mold 162 will be warm.

The Pipe Ejectz'ng Assembly In a preferred embodiment, the transverse movement of the entire pipe ejecting assembly 268 is selectively controlled by hand operated sprocket wheel 278 which is connected by chain drive 286 to a sprocket 282 on the shaft 284, upon which the wheels 272 are non-rotatably mounted. As will be evident, hereinafter, it is quite important that the entire pipe ejecting assembly 268 be properly aligned with the axis or" the particular mold which it is to service, and means for attaining this exact alignment includean air lock assembly, generally indicated at 2% which is identical with the air lock assembly 86 described in detail hereinabove in the disclosure of the mold-feeding assembly as. That is to say, the air lock assembly 286 includes a pneumatic cylinder 288 having-a piston rod 29% maintained in a position to selectively engage an aperture in one of the rails 274 when the pneumatic cylinder is suitably energized by operation of valve 296 on operating panel 298.

The transversely movable base frame 2 7%, which consists essentially of a pair of suitably braced, longitudinally extending, spaced parallel rails 38%, which may be formed of l-beams or the like, has a second frame, generally indicated at 392, which consists essentially of a pair of suitably braced, longitudinally extending, spaced parallel rails 3434, which may be formed of I-beams or the like, mounted thereon. The second frame 392 is supported on flange wheels 3% which are arranged to roll along rails 3% when the second frame is moved longitudinally of the base frame 279. Such movement is obtained by a pneumatic cylinder 3 08, depending from the second frame 35b2, having the free end of its piston rod 310 fixed to a fixed upstanding member 312 on the base frame 27%. The

'15 pneumatic cylinder 3% is double acting and is coupled, by suitable lines, to a three-way control valve 314 located on the operating panel 298.

A pipe-ejecting carriage, generally indicated at 316, is disposed upon the rails Sitl to move longitudinally thereof on wheels 3318. The pipe-ejecting carriage 316 is positively actuated to move longitudinally of second frame 3% by a chain drive 32% extending longitudinally of the rails 3M, and approximately midway therebetween, at a level sli htly below their upper surface. The chain drive 32*?) is secured, at each end, to the pipe-ejecting carriage 315, as by draw bolts 322 (FIGURE and extends around an idler sprocket 32 i mounted at the mold end of the rails 32% and around a power sprocket 326 mounted at the opposite end of these rails. The power sprocket 326 is non-rotatably fixed t0 the shaft of reversible air motor 332, which is remotely controlled by a four-way valve 334 located on the operating panel 293.

As the pipe-ejecting carriage 316 serves to convey a section of newly formed plastic pipe 335, there are provided several pipe-supporting rollers 336 to bear the weight of, and to support, the pipe during the periods when it is on, or partially on, the pipe ejecting assembly 258. These pipe-supporting rollers are substantially identical with the mandrel-supporting rollers 13% described in detail in the disclosure of the mold-feeding assembly 63, and each are, when in their operative position, located midway between the rails 394 and at a level slightly below the surface thereof.

Each set of rollers 336 consists of an opposed pair of spaced coaxial truncated conical rollers having their minor ends facing each other. As is best shown in FiGURE 18, when the pipe-supporting rollers 336 are operatively positioned at a level to support a newly formed pipe 335, and particularly a pipe of relatively small diameter, they will necessarily be located along the longitudinal path of the pipe-ejecting carriage 316. It is therefore within the contemplation of this invention to provide means for moving the pipe-supporting rollers 336 from their usual position when the pipe-ejecting carriage passes by.

To effect this end, each of the rollers 336 are rotatably mounted at the free end of one of two rocker arms 37% which extend, in spaced parallel relation, radially outward from a rocker arm shaft 372 which is rotatably mounted in suitable bearings (not shown) to extend under, and transversely of, the rails 394. An operating arm 376 is fixed to the rocker arm 372 and extends radially thereof. In the preferred embodiment illustrated, this rocker arm is angularly displaced from the rocker arm 37d and is pivotally connected to a drive rod 33%) which is, in turn, connected with a piston rod 382 of pneumatic cylinder 334. The pneumatic cylinders 384 may be selectively operated from the operating panel 2% at such times as the pipe-ejecting carriage 3'16 approaches a given set of pipe-supporting rollers 336, or, as in this preferred embodiment, this operation may be entirely automatic by the provision of suitable mechanically operated valves, such as are well known in the art and need not be described in detail herein, which operate the pneumatic cylinders to lower the rollers 336 as the pipe-ejecting carriage 316 approaches.

it should be noted that the opposed truncated ends of the pipe-supporting rollers 336 are spaced from one another a distance sufficient to allow clearance of the chain drive 329 when the opposed rollers move as a unit, through an arc defined by the movement of rocker arms 37 While the preferred embodiment illustrated in FIGURES l8 and 19 has two sets of pipe-supporting rollers 336, it should be understood that it may be desirable to provide additional sets of rollers, particularly when the pipe being ejected from the :mold 76 is unusually long. In such a case, each set of pipe-supporting rollers would be provided with a means for lowering the rollers below the path of the passing pipe-ejecting carriage 316 which are similar to the means which have just been described.

Referring more particularlyto FIGURE 20, mounted upon the pipe-ejector carriage 36 is a pipe-ejector pullout. As has been described hereinbefore, the end of the pipe mold 162 nearest the pipe-ejecting assembly 268 is counterbored and loosely fitted with a reinforcing coilar res, usually having an internal diameter equal to that of the rest of the mold, although it may have a threaded interior if threaded pipe is being cast. Generally speaking, the pipe-ejector pullout consists of an axially expanding circular wedge which is inserted within the lumen of the newly formed pipe 335 and then expanded to bear against the inner periphery thereof. The pipe is not distorted or injured as it has been cast in a closely fitted relation to the reinforcing collar 166. A hydraulic jack mounted on the pipe-ejecting carriage is then energized to urge the expanded wedge, and the pipe and reinforcing collar grasped thereby, toward the mold-ejecting carriage. The movement imparted by the hydraulic jack is relatively short, it being sufiicient that the entire length of newly cast pipe be moved a short distance so as to break the typical initial bond or adhesion between the pipe and the mold 162. The pipe is then completely withdrawn from the mold by the use of a powerful winch to draw the pipe-ejecting carriage along the rails 304. This apparatus will now be described in detail.

As shown in FIGURE 20, a cylindrical sleeve 480 mounted upon carriage 316 has a snugly fitting operating rod 4&2. extending therethrough. A tube 464 is coaxially cantilevered from the sleeve 4%, and extends towards the mold assembly '76. The tube 434 has a longitudinally extending lzeyway 406 therein and has an interior diameter somewhat greater than the exterior diameter of operating rod dill. Slidably mounted and keyed (by key 407 fitting in keyway 436) within the tube 4M is a sleeve 408 which is interiorly dimensioned to receive the operating rod 4&2 and has at least a portion of its lumen interiorly threaded to engage raised threads 410 formed upon a portion of the operating rod. The free end of the operating rod nearest the mold assembly 76- is reduced and formed with a truncated conical projection 412 which flares outwardly toward the free end thereof. The opposite end of the operating rod extends through a hollow hydraulic jack, generally indicated at 4 14-, and has an operating wheel 416 fixed on the extreme end.

The conical projection 412 is provided with a segmental collar ring composed of four chordal elements 418 (FIGURE 21) held together, and about the conical projection, by a tension spring member 426 disposed in a peripheral groove 422. The segmental collar ring is formed with an interior taper complimentary with that of the conical projection 412. and has an exterior periph eral surface defining a right cylinder. In a preferred embodiment, the exterior or peripheral surface of each chordal element is formed with a number of fine serrations thereon so as to give it a better grip on the interior periphery of the pipe 335, as will be explained. In operation, the conical projection 412, circumscribed by the segmental ring 418, is inserted within the end of the mold 162 and so located that the segmental ring is within the area thereof which is fitted with the reinforcing collar 166. Rotation of operating rod 492, by suitable manipulation of wheel 416, causes an axial movement thereof, away from the mold 162, due to the engagement of the thread 419 with the threaded interior of keyed, and hence non-rotatable, sleeve 4%. The segmental collar 418, which is biased by tension spring 420 to snugly fit on the conical projection 412, moves towards the sleeve 463 until its end abuts the planar end surfaces of the sleeve. Further axial movement of the operating rod 492, and the conical projection 412, in the same direction, will cause the respective elements of the segmental ring to ride up the conical element until its peripheral surface contacts the interior of the pipe 335. It will now be seen that once such contact is made, further axial movement of the operating rod dill. will serve to wedge the serrations on the peripheral surfaces of the segmental ring 418 tightly against the interior of the newly cast pipe 335. As has been pointed out hereinabove, the strong reinforcing collar 166 snugly circumscribes this portion of the pipe 335 so there is no danger of distorting or injuring the pipe as long as reasonable forces are used. It will now be understood that the minor interior diameter of the conical projection 412 must be less than the interior diameter of the free end of the sleeve 408, so that the end of the segmental ring will properly abut the latter.

At this time the hollow hydraulic jack 414 is energized to urge the hub 420 of the operating wheel 416 away from the pipe-ejecting carriage 3 16. This movement will be experienced by the conical projection 412 and the segmental ring 413 and will tend to pull the pipe 335 out of the mold 162. As has been stated hereinbefore, this movement is only for a very limited distance, it being quite sufiicient that the pipe be moved enough to break the bond or adhesion between the newly cast pipe 335 and the mold 162.

As shown in FIGURES 18 and 19, a winch 434i, powered by a prime mover 432, is mounted at the end of second frame 302 furtherest from the mold assembly 76, and a cable 436 is rove about the Winch. The free end of the cable 436 is fitted on pipe-ejecting carriage 316 and is utilized to draw the latter along rails 304, and, hence withdraw the newly cast pipe 335 from the mold 162 after the hydraulic jack 414 has been operated to break the initial bond or adhesion between the pipe and the mold. When the winch is being operated, the reversible air motor 332 is vented by the operation of valve 334 so that the motor offers no resistance to the winch. In a preferred embodiment, the operating controls 438 for the winch may be located on the operating panel 298 alongside the valve 334-. As the pipe-ejecting carriage moves away from the mold, the pipe-supporting rollers 336 will rise to their operative position to provide suitable support for the length of the pipe 335 being withdrawn from the mold in a manner similar to the action of the mandrel support rollers 136 described hereinabove.

After the pipe has been completely withdrawn from the mold, the operating wheel 416 is rotated to relax the grip of the segmental collar ring 418 on the inner periphery of the pipe, in a manner that will be understood, and then the pipe-ejecting carriage is moved away from the pipe a distance sufiicient to clear the conical projection 412 and the segmental ring 418 from the interior of the pipe. The

pipe is then removed from the pipe-ejecting assembly 268, by any suitable means, and the pipe-ejecting carriage is moved back to the mold end of the second frame 392 by the air motor 332 and the chain 329 so as to be ready to begin a new pipe-ejecting operation.

In FIGURES 18 and 19, the second frame 302 is illustrated as being so positioned as to be spaced from the mold assembly 76, when the pipe 335 is being withdrawn from the mold 162. It should be understood, however, that when the hydraulic jack 414 is being operated to break the bond between the mold and the pipe, the mold end of the second frame 392 is positioned to abut the end of the mold 162; otherwise the pulling force of the jack would have a tendency to pull the mold 162 out of the mold assembly 76.

This application is a divisional of my co-pending application Serial No. 594,565, filed June 28, 1956, now Patent No. 2,997,737, issued August 29, 1961.

Having described only a typical preferred form and application of my invention, i do not wish to be limited or restricted to specific details herein set forth but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and falling within the scope of the following claims:

We claim:

1. Apparatus for the casting of fibronsly reinforced pipe of heat settable material including the combination comprising: an elongated tubular mold; an elongated enclosure having open ends and dimensioned to receive said mold; said mold being disposed within said enclosure and mounted for rotational movement about its own axis therein; sealing means engaging said mold and said enclosure to define an annular heater chamber between said enclo sure and said mold; at least one end of said mold being counterbored for a distance constituting a nominal portion of its axial length; an annular reinforcing ring dimensioned to fit within the counterbore of said moldand having an interior diameter at least as great as that of the mold; cover means fittable on the respective ends of said mold, the cover means at a counterbored end of said mold being arranged to fit the mold without interfering with said reinforcing ring; said cover means defining an aperture coaxial with the mold when the last-mentioned means is fitted thereto; heat exchange means to provide mold temperature control fluid to the heating chamber; and means to impart rotational movement, independent of said enclosure, to said mold.

2. The apparatus defined in claim 1 and further including means for introducing heat settable material into said mold, said means comprising nozzle means introduceable into the apertures in said cover means, and means for propelling the heat settable material through the nozzles, and through the apertures, into said mold.

3. The combination defined in claim 1 and further including means for introducing blasts of air into alternate ends of said mold when pipe is being cast therein, said means including air compression means, ducts means disposed at each end of said mold, means to alternately position each of said duct means to direct air from said compression means into an end of said mold, and valve means arranged to block a given one of said duct means from said compression means when such a duct means is not positioned to direct air into an end of said mold.

4. The combination defined in claim 1 and further including means for introducing blasts of air into alternate ends of said mold when pipe is being cast therein, said means including air compression means, ducts means disposed at each of said mold, means to alternately position each of said duct means to direct air from said compression means into an end of said mold; means for introducing heat settable material into said mold, said means comprising nozzle means introduceable into the apertures in said cover means, and means for propelling the heat settable material through the nozzles, and through the apertures, into said mold.

5. Apparatus for the casting of fibrously reinforced pipe of heat settable material including the combination comprising: an elongated tubular mold; an elongated enclosure having open ends and dimensioned to receive said mold; said mold being disposedwithin said enclosure and mounted for rotational movement about its own axis therein; sealing means engaging said mold and said enclosure to define an annular heater chamber between said enclosure and said mold; cover means fittable on the respective ends of said mold; said cover means defining an aperture having portions coaxial with the mold; heat exchange means to provide mold temperature control fluid to the heating chamber; means to impart rotational movement, independent of said enclosure, to said mold; means for introducing blasts of air into alternate ends of said mold when pipe is being cast therein, said means including air compression means, ducts means disposed at each end of said mold, means to alternately position each of said duct means to direct air from said compression means into an end of said mold, and valve means arranged to block a given one of said duct means from said compression means when such a duct means is not positioned to direct air into an end of said mold.

6. Apparatus for the casting of fibrously reinforced pipe of heat settable material including the combination comprising: an elongated tubular mold; said mold being mounted for rotational movement about its own axis; means to impart rotational movement to said mold; heating means to heat said mold, and its contents, While the same is being rotated about its own axis; cover means fittable on the respective ends of said mold; said cover means defining an aperture having portions coaxial with the mold; means for introducing blasts of air into alternate ends of said mold through said apertures in said cover means when pipe is being cast therein, said means including air compression means, ducts means disposed at each end of said mold, means to alternately position each of said duct means to direct air from said compression means 10 into an end of said mold, and valve means arranged to 2% block a given one of said duct means from said compression means when such a duct means is not positioned to direct air-into an end of said mold.

References Cited in the file of this patent UNITED STATES PATENTS 1,161,756 Wolever Nov. 23, 1915 1,832,066 Von Webern Nov. 17, 1931 1,840,027 Fetter Ian. 5, 1932

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3239906 *Aug 13, 1962Mar 15, 1966Muntanola Ribot LuisProcess for making centrifugated pipes, and machine for realization thereof
US3341387 *Jan 29, 1964Sep 12, 1967Universal Moulded Fiber GlassApparatus and method for filament winding and curing on a plurality of mandrels
US4230660 *Jan 16, 1979Oct 28, 1980The United States Of America As Represented By The United States Department Of EnergyEpoxy-borax-coal tar composition for a radiation protective, burn resistant drum liner and centrifugal casting method
US4714578 *Sep 26, 1984Dec 22, 1987Fibercast CompanyMolding of integral socket connection in centrifugally cast fiberglass reinforced pipe
Classifications
U.S. Classification425/112, 425/126.1, 425/436.00R, 425/446, 264/311, 425/129.1, 425/435, 264/103
International ClassificationB29C70/32, B29C70/04
Cooperative ClassificationB29C70/326
European ClassificationB29C70/32A2