US 3691992 A
Apparatus for truing a cement mortar coating on a concrete pipe body or the like including means for supporting and rotating the body and a power-driven rotary brush mounted to be moved longitudinally of the body.
Claims available in
Description (OCR text may contain errors)
United States Patent Beemer 154] APPARATUS FOR TRUING MORTAR COATING  Inventor: Paul K. Beemer, Laguna Beach,
Calif. g  Assignee: Ameron, lnc., Monterey Park, Calif.
 Filed: Dec. 26, 1968  Appl. No.: 786,968
 U.S. Cl. ..ll8/l07, 118/113, 118/321,
425/106 51 1111.01 ..B05c 11/02 581 Field of Search ..25/1 A, 38, 30 R, 30 A; 118/112, 113, 321, 107; 15/104.04, 88; 264/162; 425/106  References Cited 1 UNITED STATES PATENTS 2,969,104 l/l96l Schubert et a1 ..264/162 x 1 51 Sept. v19, 1972 1,281,407 10/1918 Marquess ..118/321 UX 2,256,983 9/1941 Lecker ..15/179 2,751,617 6/1956 McLaggan ..15/88 3,121,898 2/1964 Morain ..15/88 2,368,742 2/1945 Brend ..25/38 X 2,204,785 6/ 1940 Bennett ..25/38 X 2,373,672 4/1945 Ferla ..25/30 A UX 3,388,039 6/1968 Gillis et a1 ..25/30 A X R16,523 1/1927 Bille ..25/30 A Primary Examiner-Robert D. Baldwin Attorney-Walter G. Maxwell and Christie, Parke & Hale et a1.
[5 7] ABSTRACT Apparatus for truing a cement mortar coating on a concrete pipe body or the like including means for supporting and rotating the body and a power-driven rotary brush mounted to be moved longitudinally of the body.
10 Claims, 9 Drawing Figures PATENTED 3,691,992
sum 1 0F 3' 57 PAUL, K BEE/WEI? .1: 1 2 INVENTOR.
TT02JEYS PATENTEDSEP 19 m2 SHEEI 2 UF 3 INVENTOR. P/WJL K. BEE/WEE p 1 roedz YS PATENIEDsEP 19 m2 SHEET 3 [IF 3 INVENTOR. Paul. K. BEE/ 152 APPARATUS FOR TRUING MORTAR COATING The invention has to do generally with the making of prestressed concrete pipe of a type wherein the pipe body is wrapped with one or more layers of high tensile-strength wire under tension and particularly with the preparation of a cement mortar coating or layer on the pipe body for the wrapping of a layer of wire therearound.
In the manufacture of one type of prestressed concrete pipe, the cast concrete body with internal reinforcement steel usually includinga metal cylinder is wound with wire under tension and the wire secured in place. In large-diameter pipe it has been found economically more feasible to employ two layers of relatively small-diameter wire rather than one layer of larger diameter wire, and this is accomplished by first wrapping the cured pipe body with the first layer and covering this with cement mortar. After the mortar coating is cured a second wrapping of wire is placed in tension about the coating and in turn covered with an outer coating of cement mortar.
In order to insure corrosion prevention of the steel wire it is essential that the cement mortar be-in intimate surface contact with the steel and that there be no pockets or voids in the coating next to the wire. Hence it is desirable to have a relatively smooth true surface upon which to wrap the second layer of wire under tension. Various means, including screeds of different constructions and materials, have been used in an attempt to smooth or true the outer surface of the cement mortar coating, however these have not proved successful due to the fact that such mortar coating usually is applied relatively dry and includes aggregate as large as pea size.
An object of the present invention is to provide a novel apparatus for making pipe of the type indicated which assures the provision of a relatively true surface on the exterior of the first mortar coating covering the first wire wrapping. It is also an object to provide apparatus for truing any freshly applied mortar coating on a cylindrical body.
More particularly it is an object to provide novel means for truing the surface of a newly applied coat of cement mortar to a pipe body by gradually removing an outer portion of the coating. In this connection it is an object to provide apparatus including a motor-driven brush for use with a rotating pipe body and means for moving the brush longitudinally of the body to effect a truing of the coating.
In summary, the invention is concerned with the removal of the outer portion of a coating of cement mortar from a cylindrical body by means of a motordriven wire brush moved longitudinally of the body as the latter is rotated to produce a relatively true cylindrical surface.
Referring to the drawings:
FIG. 1 is a diagrammatic elevational view of ap- FIG. 5 is a diagrammatic plan view showing the application of the invention to a pipe body supported horizontally; v
FIG. 6 is a fragmentary sectional view on line 6-6 of FIG. 5;
FIG. 7 is a fragmentary longitudinal sectional view of a completed pipe body:
FIG. 8 is a diagrammatic elevational view of an alternate form of the invention in conjunction with a partially completed pipe body; and
vFIG. 9 is a fragmentary sectional view on'line 9-9 of FIG. 8.
More particularly describing the invention, in FIG. 1, which is largely diagrammatic, a partially completed concrete pipe 11 is shown supported on a turntable 12 that is adapted to be rotated by an electric motor 13 through a suitable drive train 14. The pipe comprises a cylindrical body 15 of concrete having internal reinforcement (not shown) and a single layer of wire 17 therearound under tension. The wire is shown as partially covered by a coat of cement mortar 20 which may be applied by any means known in the art, as, for example, by a pair of opposed, motor-driven brushes 21 which are supplied with mortar from a hopper 22 and propel the mortar onto the surface of the pipe body as it rotates with the turntable. The mortar-applying means is carried on the platform 24 of an elevator 25 which is adapted to move vertically in an upright structure 26 so that it moves longitudinally or axially of the pipe body. The elevator may be raised and lowered by being suspended on chains 29 driven by a motor 30 and suitable drive sprockets and drive train, the structure 26 including four upright columns 31 spaced laterally, as at the corners of a rectangle.
The elevator 25 also carries the means for truing the mortar coating which has been applied, such means being generally designated by the numeral 28. Referring now particularly to figures 2-4, the means for effecting the removal of a portion of the mortar and the truing of the outer surface thereof comprises a motordriven brush 33 carried on an arm 34 which is pivotally mounted on a lower cross frame member 35 of the elevator. The arm is generally L-shaped and may be made in sections, as shown, for convenience of assembly and disassembly. The inner lower end section 35 of the arm is pivotally mounted on pin 36 between two spaced ears 37 which project from frame member 35 at the edge of the elevator. Beyond the inner section is an outer section 38 which is bolted to section 35, the parts having similar flanges 39 for that purpose. Section 38 has a short portion 40 and beyond this a long section 41 at right angles thereto, these parts being tubular, with a web 42 welded to each.
A brush housing 45, which includes two parallel laterally spaced plates 46 and 47, welded or otherwise secured to a cylindrical member 48, is mounted on the outer end of the am, the member 48 being received in section 41 of the arm. Plate 47 is apertured to receive a cap screw 50 that passes through an arcuate slot 51 in a flange 52 at the outer end of section 41 of the arm. With this arrangement the housing can be rotatively adjusted with respect to the arm, and nuts 53 tightened on the screw 50 to secure the parts in adjusted position.
The brush housing forms a brush-receiving chamber 55 which is open at one side, the brush 33 projecting beyond the plane of the edges 56 of the open side. The
brush is mounted on a short shaft or arbor 58 that is journaled in the pillow block 59 and bearing 60 and the arbor or shaft is provided with sheaves 61 at one end to be driven by belts 62 trained around Sheaves 63 on the shaft of an electric motor 64 mounted at the side of the housing.
While various types of brushes can be used, it is preferable that the brush be one having steel bristles and that the shape of the brush be somewhat conoidal and so mounted that, in use, the smaller end will be foremost as the brush is advanced longitudinally of the pipe body, that is, upwardly as it appears in FIG. 1 and 2 of the drawings. The angle of the surface of the brush to its axis need not be great and is most effective when the difference in radii between the trailing end and leading end of the brush is equal to the average thickness of mortar being removed from the pipe surface.
For the purpose of pivoting the arm 34 a fluid ram 66 is connected between it and a bracket 67 on the cross member 35 of the elevator. The cylinder 68 of the ram is pivotally mounted by trunnions 69 between two plates 70 and 71 of bracket 67. The piston rod 73 of the assembly is pivotally connected by a clevis 74 and pin 75 to a mounting lug 76 on the arm. In FIGS. 2 and 3 the parts are shown in operative position in full lines, but it will be apparent that the motor-driven brush assembly may be retracted or moved to an out-of-the-way position by the ram, as indicated by the broken-line position thereof FIG. 3 wherein the assembly abuts an adjustable stop screw 78.
A further object of the invention is the provision of a remotely controlled stop or abutment for the rotary brush assembly. Referring to FIGS. 3 and 4, it will be seen that a jackscrew 80 which has a special nose 81 projects through a bushing 81' in position to be abutted by and thus serve as a stopfor the arm 34 of the brush assembly. The jackscrew is turned by an actuator 82 driven by motor 83 through gearing 84 and shaft 85. A cam 86 on the shaft operates a microswitch 87 which may be used to sense rotation of the shaft so that an operator can make small adjustments of the stop from a remote point, any conventional circuitry being suitable.
In carrying out the method and using the apparatus, a cured body of concrete 20 which has a single wrapping or layer of wire l7 therearound under tension is mounted on the turntable 12 and secured in any suitable manner. It is then rotated and coated from end to end with a layer 20 of cement mortar to a depth substantially greater than the diameter of the wire with the coating apparatus 21 previously described. Before the applied coating has a chance to set, it is trued by removing an outer portion thereof by means of brush 33 which is rotated oppositely to the direction of rotation of the pipe body at a relatively high speed relative to the speed of rotation of the pipe body. The latter is preferably rotated to produce a surface speed within the range of from 300 to 700 feet per minute while the brush is preferably rotated at a speed of about 2,000 rpm, although this speed is not critical. The brush moves longitudinally or axially of the pipe body, following the mortar coating apparatus since it is mounted on the same elevator, and leaves a relatively true fresh surface 90 on the mortar coat 20.
The coating 20 is then cured conventionally and subsequently a second wire is wrapped around this coating under tension and secured. Preferably a wet cement slurry of water and cement is applied to the surface 90 just ahead of the second wire wrapping applied therearound so as to insurethe filling of any depressions or voids beneath the wire wrap. Subsequently the second layer or wire wrap (not shown) is covered with a coating of cement mortar (not shown) and this is cured. In the event a third or subsequent layer of wire is to be added, the coating of mortar over the second layer of wire would be trued in the manner previously described.
It will be appreciated that the rotary brush 33 can be used fortruing mortar coatings on other types of pipe or other cylindrical bodies. Thus in FIGS. 5-7, by way of example, there is shown another type of pipe 101,
the incomplete body 102 of which is normally supported horizontally between rotatable heads 104, one of which is driven by a motor 105 through suitable drive train means 106 for the purpose of rotating it during coating and truing of the coat. In this case the pipe includes a steel cylinder 107 in which a mortar lining 108 has been applied and cured. The pipe body in its partially fabricated condition,- comprising the lining 108 and the cylinder 107, is then mounted for rotation, as shown in FIG. 5, and coated with a layer of cement mortar 110 by means of apparatus 21, 22 such as that previously described. Such apparatus is mounted ona carriage 112 adapted to run on a track 113 disposed parallel to the rotary axis of the pipe body. Any suitable means is provided for propelling this carriage, as, for example, a chain drive 114 connected to the carriage and passing aroundsprockets 115 and 116, the latter of which is driven by a motor 117 through drive train means 118.
The mortar coating layer 110 is trued by the action of a motor-driven rotary brush 33 such as previously described, but here shown mounted on carriage 112. Thus the brush travels longitudinally of the pipe body and is rotated oppositely to the direction of the rotation of the pipe body.
After the mortar coating layer 110 has cured, the pipe is completed by wrapping high tensile wire 120 around the coating (either with or without a pre-coating or simultaneous coating of cement slurry) and secured in place. This wrapping is then covered with a protective outer coating of cement mortar which is cured, designated 122.
While it is believed to be preferable to use a brush of the shape previously described which rotates on an axis substantially parallel to the axis of rotation of the pipe body support means, it is conceivable that brushes of other shapes can be used satisfactorily and that such brushes, as well as the brush previously described, may be oriented differently with respect to the body whose mortar coating is to be trued. Merely to give one such example, in FIGS. 8 and 9 there is shown a partially completed cylindrical pipe body which may be assumed to be supported and rotated about its axis in any suitable manner. A coatingof cement mortar 131 is shown being applied by an applicator means 21 on a traveling support which may be assumed to move longitudinally of the body 130. A brush 133 is mounted at 134 on the same support and trails the means 21,
being rotated by a motor 136. In this case the brush has its axis of rotation normal to the axis'of rotation of the body 130 and parallel to a line tangent to the surface thereof.- The brush is shaped to be somewhat concave and to substantially cofit the pipe body.
In operation, the pipe body would be rotated at the proper speed for applying the coating which would have an outer surface 138 as left by the coating means. The rotating brush 133 (rotating counterclockwise as viewed in FIG. 8), would then remove sufficient cement mortar to produce and leave the relatively true, smaller diameter surface 139.
Although I have illustrated and described preferred forms of my invention, I contemplate that various changes and modifications can be made therein without departing from the invention, the scope of which is indicated by the following claims.
1. ln apparatus for making a pre-stressed concrete cylindrical pipe body, means for truing a coating of cement mortar thereon in preparation for the subsequent winding of a reinforcement wire therearound under tension comprising a support for the pipe body, a carriage movable alongside and longitudinally of a pipe body on the support, means for moving said carriage, means on the carriage for applying a coating of cement mortar to the pipe body, a rotatable motor-driven conoidal brush mounted on the moving carriage in trailing relationship with the mortar applying means and spaced from the pipe body to remove only a portion of the previously applied cement mortar coating as the brush rotates and to progressively remove the portion of the coating from a point spaced behind the mortar applying means as the carriage moveslongitudinally of the pipe body, said brush being mounted so it rotates on an axis substantially parallel to the axis of the pipe body and so that in normal use, its smaller end is adjacent to the mortar applying means as the brush moves longitudinally of the pipe body, and means for moving one of said support and carriage in a manner to result in relative rotation of the pipe body and carriage.
2. The apparatus set forth in claim 1 in which said support is rotatable and in which means is provided for rotating the support.
3. The apparatus set forth in claim 2 in which said motor-driven brush is mounted on a swingable arm pivotally mounted on the carriage, and in which adjustable means is provided for limiting pivotal movement of the arm in a direction toward said pipe body.
4. Apparatus for truing a coating of cement mortar on a concrete pipe body while the mortar is still fresh comprising a support alongside the pipe body and movable longitudinally thereof, means on the support for applying a coating of cement mortar to the pipe body, a rotatable motor-driven conoidal brush carried on said support in trailing relationship with the mortar applying means and spaced from the pipe body to remove only a portion of the previously applied cement mortar coating as the brush rotates and to progressively remove the portion of the coating from a point spaced behind the mortar applying means as the carriage moves longitudinally of the pipe body, said brush being mounted so it rotates about an axis substantially paral lel to the axis of said pipe body, and so that, in normal use, its smaller end is adjacent to the mortar applying means as the brush moves longitudinally of the pipe body, means for moving said support longitudinally of the pipe body, and means for rotating the support or the pipe body so as to result in relative rotation of the pipe body and support.
5. The apparatus of claim 4 in which said brush is carried on an arm swingably mounted on the support, and in which adjustable means is provided for limiting swinging movement of the arm toward the pipe body.
6. The apparatus of claim 5 in which remotely controlled means is provided for operating said adjustable means.
7. The apparatus set forth in claim 1 in which the axes of rotation of the pipe body and the brush are in a substantially vertical plane so that the removed portion of the coating can be directed downward for collection and reuse.
8. The apparatus set forth in claim 4 in which the axes of rotation of the pipe body and the brush are in a substantially vertical plane so that the removed portion of the coating can be directed downward for collection and reuse.
9. In apparatus for making a prestressed concrete cylindrical pipe body, means for truing a coating of cement mortar thereon while the mortar is still fresh in preparation for the subsequent winding of a reinforcement wire therearound under tension, comprising a support for the pipe body, a carriage movable alongside and longitudinally of the pipe body on the first support, means for so moving said carriage, means on the carriage for applying a coating of cement mortar to the pipe body, a motor-driven brush mounted on the carriage in trailing relationship with the mortar applying means and positioned such that the brush is engageable with at least a portion of the cement mortar coating on the pipe body while the mortar is still fresh, said brush being rotatable on an axis substantially parallel to the axis of the pipe body so as to remove a portion of the coating previously applied, the axis of the pipe body and the axis of rotation of the brush being in a substantially horizontal plane, with the point of engagement of the brush and the coating being below the axis of the pipe so that the removed portion of the coating can be directed downward for collection and reuse, and means for moving one of said support and carriage in a manner to result in relative rotation of pipe body and carriage.
10. Apparatus for truing a coating of cement mortar on a concrete pipe body 'while the mortar is still fresh comprising a support alongside the pipe body and movable longitudinally thereof, means on the support for applying a coating of cement mortar to the pipe body, a motor-driven brush carried on said support in trailing relationship with the mortar applying means and positioned such that the brush is engageable with at least a portion of the cement mortar coating on the pipe body while the mortar is still fresh, said brush being rotatable about an axis of rotation substantially parallel to the axis of said pipe body, the axis of rotation of the brush and the axis of the pipe being in a substantially horizontal plane, with the point of engage- -ment of the brush and coating being below the axis of the pipe so that the removed portion of the coating can be directed downward for collection and reuse, means for moving said support longitudinally of the pipe body,
and means for rotating the support for the pipe body so as to result in relative rotation of the pipe body and support.