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Publication numberUS3894509 A
Publication typeGrant
Publication dateJul 15, 1975
Filing dateSep 10, 1973
Priority dateSep 10, 1973
Also published asCA1033116A1, DE2443201A1, DE2443201C2
Publication numberUS 3894509 A, US 3894509A, US-A-3894509, US3894509 A, US3894509A
InventorsRichard J Duffy, Richard M Elliott, Philip J Rodden
Original AssigneeUsm Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for manufacture of fasteners
US 3894509 A
Abstract
Apparatus and method are provided for the continuous manufacture of self-locking internally threaded fasteners having a locking body or patch comprised of resilient thermoplastic material, applied to the fastener in powder form. A support member having a plurality of cavities for receiving said fasteners, and a nozzle associated with each of said cavities, is moved along a path through a plurality of locations wherein the fastener is deposited at a cavity aligned with a respective nozzle at a first location, material is forced through the nozzle onto the fastener at a second location, the fasteners are removed from the respective support at a third location, and the nozzles are purged of material at a fourth location prior to the initiation of a subsequent sequence of operations by the apparatus.
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United States Patent 11 1 Duffy et a1.

1 1 APPARATUS FOR MANUFACTURE OF FASTENERS [75] Inventors: Richard J. Duffy, Salem; Richard M. Elliott; Philip J. Rodden, both of Beverly, all of Mass.

[73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: Sept. 10, 1973 {21] Appl. No.: 396,094

{52] US. Cl. l. 118/50; 117/18; 118/501; 118/317; 118/326; 118/319; 10/10 P; 10/86 A [51] Int. Cl BOSb 7/14 [58] Field of Search 118/50, 24, 326, 50.1, 118/317, 319, 324; 117/18 [56] References Cited UNITED STATES PATENTS 2.333.557 11/1943 Fischer 118/317 2,766,484 10/1956 Sanderson 1 1 118/50 3.311.085 3/1967 Smith 118/50 3,452,714 7/1969 Burke et a1. 1 1 4 4 118/308 3.530.827 10/1970 Burke 1 1 118/319 3,557,750 1/1971 Gallagher 118/319 1 July 15,1975

Primary Examiner-W. C. Reynolds Assistant Examiner-Douglas Salser Attorney, Agent, or Firm-Aubrey C. Brine; Vincent A. White; Richard B. Megley 1 ABSTRACT Apparatus and method are provided for the continuous manufacture of self-locking internally threaded fasteners having a locking body or patch comprised of resilient thermoplastic material, applied to the fastener in powder form. A support member having a plurality of cavities for receiving said fasteners, and a nozzle associated with each of said cavities, is moved along a path through a plurality of locations wherein the fastener is deposited at a cavity aligned with a respective nozzle at a first location, material is forced through the nozzle onto the fastener at a second loca tion, the fasteners are removed from the respective support at a third location. and the nozzles are purged of material at a fourth location prior to the initiation of a subsequent sequence of operations by the appara- 22 Claims, 9 Drawing Figures APPARATUS FOR MANUFACTURE OF FASTENERS BACKGROUND OF THE INVENTION The present invention relates to improved apparatus for the manufacture of self-locking internally threaded elements and more particularly to a device for the continuous manufacture of elements such as fasteners wherein the self-locking feature is obtained through a deformable plastic patch secured onto the threaded internal surface of the element.

In US. Pat. application Ser. No. 314,854 entitled Method of Making Self-Locking Internally Threaded Articles" filed in the name of R. J. Duffy, and assigned to the assignee of the present invention, there is disclosed a method and apparatus for making a selflocking threaded element which avoids the difficulties of resin deposit on the end faces of the threaded ele ment, is effective to deposit resin on the threaded surface in the selected area with a minimum of spatter on other portions of the threaded surface. In that method and device as disclosed, a nut or other internally threaded member was heated. and while mounted with its axis in an up-and-down position was sprayed with finely divided resin particles which were caught and built up on the heated surface to form a plastic body. While the apparatus disclosed in that application has proven quite satisfactory for practicing the method dis closed therein, it has been found that in the mass production of such internally threaded elements, as is desirable for a commercial application of the method, improvements may be made to the apparatus.

For example, automatic means may be provided to continuously move the internally threaded elements through the various stations in which the elements are loaded, the patch is applied to the elements, and the elements are unloaded at a substantial rate. In so doing, it has been found that small amounts of resin material left on the various components of the apparatus is quite detrimental to the elimination of the material deposited on the end surface, or end lead threads of the element. Additionally, in order to insure that the self-locking feature is obtained, the element while being moved through the device in a continuous manner, must be precisely located such that the patch is received at a specific location on the internal threads.

In view of the above therefore, the present invention has as an object to provide an improved device for the manufacture of self-locking internally threaded elements wherein a locking body or patch comprised of resilient thermoplastic material is applied to the element at a precise location, in powdered form.

A further object of the invention is to provide a device for the continuous manufacture of self-locking internally threaded elements which is simple in operation and relatively inexpensive to manufacture and operate.

Still another object of the invention is to provide a device for the manufacture of self-locking internally threaded elements which is automatic, requires little maintenance, is reliable, and is therefore readily adaptable to a manufacturing operation wherein a plurality of such devices may be operated by a single operator.

SUMMARY OF THE INVENTION The above objects of the invention are achieved by providing apparatus for applying locking patches of resilient thermoplastic resin to internally threaded articles having openings at both ends of the threaded portion which, in general, comprises support means for receiving the internally threaded articles, and means for moving the support means along a predetermined path wherein the article is received on the support means at a first location. Conduit means connected to the support means are provided having an opening formed therein which is directed toward that portion of the threads of the article supported on the support means to which the patch is to be applied. The conduit means has a second opening at the opposite end for receiving a thermoplastic resin in powdered form to be deposited on the threads of the article, and a discharge means is disposed for providing thermoplastic material under pressure when in registry with the second opening. A vacuum means is provided for applying a negative pressure when in registry with the second opening and the means for moving the support means along a predetermined path is effective to move the support to the location where an article is received on said support means and then to a location where the conduit means opening is moved into registration with the discharge means and subsequently to a location where the second opening is moved into registration with the vacuum means.

In a continuous cycle of operation. therefore, the conduit means are effective to apply the thermoplastic resin to the particular portion of the internal threads of an article. and are then purged of the thermoplastic resin prior to the next operation.

BRIEF DESCRIPTION OF THE DRAWING For a more complete understanding ofthe invention. reference should be made to the following description of a preferred embodiment, taken in conjunction with the drawing thereof, wherein:

FIG. I is a perspective view showing a device for the manufacture of self-locking threaded fasteners constructed in accordance with the teachings of the present inventlon;

FIG. 2 is a top plan view of the device shown in FIG. I having portions of the structure broken away to reveal underlying features;

FIG. 3 is a sectional elevational view taken along the line III-III of FIG. 2 showing details of the construc non;

FIG. 4 is a sectional elevational view taken along the line lV-IV of FIG. 2 showing further details of the structure;

FIG. 5 is a sectional plan view taken along the lines V-V of FIG. 4 showing that portion of the structure in detail;

FIG. 6 is a plan view showing a portion of the structure depicted in FIG. 2. taken on an enlarged scale for clarity;

FIG. 7 is an elevational view of the structure shown in FIG. 6;

FIG. 8 is a plan view showing another portion of the structure depicted in FIG. 2, taken on an enlarged scale for clarity; and

FIG. 9 is an elevational view of its structure shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, and in particular to FIGS. 1 and 2, there is shown apparatus for the manufacture of a self-locking internally threaded article in the form of a hex nut N which generally comprises a rotatably mounted transport member in the form of a table movable along a predetermined rotary path about its central axis, in the direction shown by the arrows of FIGS. 1 and 2.

As the table 10 is continuously rotated about a fixed housing 11, a point on the table 10 will be seen to pass through a plurality of stationary work areas which will be termed stages of the operation for the purposes of the present description.

During the first stage of operation. a loading chute 12 which is inclined downwardly toward the surface of the table 10 is effective to deposit the hex nut N onto the table, and during a next stage, a resilient thermoplastic material in powdered form is applied to the internal threaded surface of the nut. This stage is substantially enclosed by a vacuum hood 13, the operation of which will be explained in detail hereinbelow.

During a next subsequent stage, a second upwardly inclined chute 14 having one end disposed adjacent the table 10 is effective to unload the nut N from the table 10, which is followed by the subsequent stage of operation which substantially covers that portion of the table 10 located between the unloading station and the loading station, and wherein the means for applying thermoplastic material to the nut N are purged of residual material, and are readied for the next sequence ofoperation.

It will be noted in HO. 1, that the stationary housing 11 is provided with a funnel shaped hopper 15 which serves to receive the powdered resilient thermoplastic resin for application to the internal threads of the nuts N, which operation will be explained in detail below.

Referring now to FIGS. 25. and in particular to the table 10, the table is shown to comprise a hub 16 having a plate 17 affixed to its uppermost surface and a groove 18 for receiving a V-belt 19 which is connected to a motor (not shown). The hub 16 is slidingly engaged on the central housing 11 and is caused to rotate by the motor driven belt 19, the hub being supported by a pair of bearings 20 and 21.

Referring still to these FIGS. 25, the hub 16 is shown to have formed therein a plurality of circular cross section apertures 22 each having an opening internally toward the housing ll and receiving at the opposite end a tube 23, the tube and aperture forming in combination a conduit means, as will be explained further in detail.

As best shown in FIG, 2, the outer periphery of the plate 17 is provided with a plurality of V-shaped slots 24, each of which has a tongue 25 disposed below and extending outwardly from the respective slot to form a pocket or cavity for receiving a threaded hex nut N, of the type shown. Each of the tubes 23 has a channel bracket 26 connected to it by welding or other means and a plurality of fasteners 27 serve to connect the bracket 26 to the plate 17, with the respective tongue 25 sandwiched therebetween. Each of the tongues 25 has a circular opening provided therein and the outer end of the tube 23 is bent upwardly at approximately a angle to extend through the circular opening in the tongue, and slightly above the tongue to a position which would locate the outer end of the tube within a hex nut received in the pocket formed by the respective V-shaped slot 24.

Referring in particular to FIGS. 3, 4, and 5, the housing 11 is seen to have formed therein a hollow central opening 28 into which the hopper 15 is introduced, and which extends to a point near the bottom of the housing. The bore 28 is flanged outwardly near its midpoint, and has a slotted opening 29 which extends for substantially 180 around the housing 11 and leads from the flanged out portion of the bore 28 externally of the housing 11 and is in alignment with the plurality of apertures 22, when the table 10 is located on the housing 11. A conical shaped divider 30 is located in the flanged out portion of the bore 28 and is attached to the wall of the bore at that portion of the wall which is not cut away by the slotted opening 29. Thus, the divider 30 separates the upper portion of the bore 28 from the lower portion over the entire circumference of the bore with the exception of that portion where the slotted opening 29 is located.

An inlet opening 31 extends into the bore 28 at its lowermost extremity and is connected to a source of fluid pressure such as an air pump (not shown).

Diametrically opposite the slotted opening 29 and near the outer edge of the housing 11 are located a plurality of vertical circular cavities 32, four in number, which are best shown in FIG. 2.

Each cavity 32 has its lower end terminating in a larger diameter chamber 33, and its upper end terminating at a second slotted opening 34 similar to the diametrically opposed slotted opening 29. In this instance, the slotted opening 34 extends from the outer periphery of the hub 1! over a circumference of about to an inner wall 35 as shown in FIG. 2. The slotted opening 34 is in alignment with the apertures 22 and therefore forms a flow path from the tubes 23 through the chamber 33 to which a vacuum source (not shown) is connected, when the tubes 23 are moved into the area over which the opening 34 is formed.

Referring in particular to FIGS. 3 and 4, it will be noted from the construction that the table 10 is readily removable from the hub 11 by virtue of the removable retaining plate 36 which is secured by four fasteners in the form of screws 37. When the screws 37 are removed, the retaining plate 36 may be lifted from the structure and the table 10 removed and subsequently replaced with a table serving to receive internally threaded fasteners of a different size or shape than those which are accommodated by the table 10 shown.

Because of the necessity to provide a sliding fit between the table 10 and the central housing 11, there is a distinct possibility of material which is being trans' ferred between the tubes 23 and the slotted opening 29, or the tubes and the slotted opening 34, tending to escape between the outer surface of the hub 11 and the inner surface of the hub 16 of the table 10. There is provided. therefore, a pair of circumferential grooves 38 and 39 formed in the hub ll and extending com pletely around the hub. At a point adjacent the inner wall 35 of the slot 34 a vertical bore 40 extends upwardly through the housing 11 and is provided with a pair of passages 41 and 42 which terminate at the grooves 38 and 39. A duct 43 extends from the bore 40 and is connected to a source of air pressure (not shown) for providing a fluid pressure in the bore 40. Thus, material having a tendency to find its way be tween the hub 16 and the housing 11 is inhibited from doing so, as any air flow occurring takes place from the grooves 38 and 39 into the openings 29 and 34.

Referring now to FIGS. 1 and 2, it will be observed that the vacuum hood 13 is divided into two portions for purposes of convenience only, and both portions taken together cover the area about the housing I] wherein the slotted opening 29 is formed. That is, the entire area over which the thermoplastic resin in powdered form is fed through the tube 23 is covered circumferentially by the hood 13. Both of the portions of the hood 13 are constructed substantially the same and therefore only the first portion as shown in FIG. 1 will be described in detail.

Each of the hood portions is provided with a chamber 44 which is supplied with a negative pressure by vacuum producing means (not shown). A cover plate 45 extends outwardly from the hood 13 to a position over the table which serves to cover a nut N located on the table. For the purpose of equalizing the vacuum throughout the hood 13, a plurality of partitions 46 are located within each of the portions of the hood l3 and serve to form a plurality of separate vacuum areas. each having substantially the same negative pressure to apply to the area above the nut N located adjacent to the opening of the hood.

The feeding arrangement shown comprises the chute 12 which is supported adjacent the periphery of the table 10 and positioned with the lowermost discharge surface of the chute spaced slightly from the surface of the plate 17 and having an outer rail 47 extending beyond an inner rail 48 as best shown in FIGS. 6 and 7. The distance between the outer rail 47 and the inner rail 48 is substantially the width across the points of the hex portion of the nut N to be fed onto the table 10. Thus, as shown in FIGS. 6 and 7, the nuts orient themselves flat-to-flat when traveling down the chute 12 and are therefore aligned for engagement with the V- shaped slot 24 on the table 10. A segment 49 of the chute 12 is manufactured of a material with suitable non-inductive and heat-resistant properties, and extends through an induction coil 50 which is suitably sloped and located adjacent the chute segment for heating a nut N traveling through the segment. The nut N may be fed by any suitable commercial feeder, of the vibrating type or of any other type, and as such devices are well known in the art, they are not considered to be of importance in describing the present invention and therefore the feeder has not been shown.

At the opposite side of the table 10 from the chute 12 there is located a similarly constructed chute 14, as best shown in FIGS. 8 and 9 taken in conjunction with FIG. 1. The chute 14 is effective to remove the nuts N from the table 10 and in a similar manner to chute 12 is sloped with its lowermost end, which in this instance is the nut receiving end, disposed adjacent the top of the table 10 and has an outer rail 51 which extends beyond an inner rail 52, both rails being spaced substantially the distance across the hex portion of a nut N. The uppermost end of the chute 14 may be left open providing for the nuts N to be dropped into a receptacle (not shown) or may lead to another chute or conveyance for carrying the nuts to a subsequent work or storage area.

With respect to the particular construction of the chutes 12 and 14, the outer rail 47 of the chute 12, as viewed in FIG. 6, forms a means for guiding the nut N into the proper location in the V-shaped slot 24 of the table 10 after which the nut may be held in place by gravity for the remainder of its travel on the table, or a plurality of spring clips 60 may be employed to provide a radial retaining force to the nuts, if necessary.

Likewise, when removing the nut N. the outer rail 51 of the chute 14 serves to retain the nut in registry with the slot 24 until such time as the nut is lifted above the table and the inner rail 52 serves to combine with the rail 51 to guide the nut along the chute to its destina tion.

In operation. the apparatus as herein disclosed is first prepared by loading the hopper 15 with a thermoplastic resin in powdered form. The material may be a powder which is a mixture comprising a major portion of powdered polyamide resin. (nylon 11) and a minor proportion of epoxy resin having a particle size distribution such that less than 2% is retained on a No. sieve about retained on a N0. M0 sieve and about 5% passing a No. 325 sieve. This is substantially the same material as disclosed in the prior referenced US. Pat. application Ser. No. 3 14,854 filed in the name of Richard J. Duffy and assigned to the assignee of the present invention.

While the means for introducing thermoplastic resin in powdered form to the apparatus has been shown as a funnel type hopper 15. it should be understood that for the purposes of the invention the material could he provided from a remote source and continuously supplied by a suitable conduit to the housing I]. it should also be understood that the flow of resin material is metered by valving or other means well known in the art so as to control flow rate according to the production rate, nut size, thread size or temperature variations.

With the material introduced into the apparatus, the means for providing a vacuum to the chamber 33 and the duct 43, and the means for providing air pressure to the inlet opening 31 are activated. Also external to the housing 11, the means for providing a vacuum to the hood 13 is initiated. and the induction coil 50 is energized to provide heating of the nuts N as they are di rected along the chute 12.

With the preliminary steps set forth above having been taken. the apparatus is in the ready state and the motor means for driving the belt 19 and means for feeding the nuts N onto the chute 12 are activated to initiate processing of a typical batch of internally threaded fasteners. As the table 10 rotates at about l0 revolutions per minute in the direction of the arrows shown in FIGS. 1 and 2, the nuts N are introduced into the chute 12 and travel flat-toflat through the induction coil 50 where each nut is raised to a temperature sufficient to cause the above described thermoplastic powder to adhere to the threaded surface of the nut when contacted thereby. and to be fused by heat from the surface to form a continuous plastic body. As a nut N approaches the table 10 it is retained on the chute 12 by the outer rail 47 until it is in registry with a V-shaped slot 24 and thereby positioned over a respective tube 23 disposed with its discharge opening at the threaded opening of the nut. The table 10 is rotated at a constant speed (about 10 revolutions per minute) and each nut N remains on the table for about /2 revolution or about 3 seconds with the discharge opening of the hollow tube 23 disposed to project slightly into the threaded opening of the nut.

As the table 10 rotates, each tube 23 is moved such that its respective aperture 22 comes into registry with the slotted opening 29 and the nut located adjacent the tube discharge opening is simultaneously disposed below the cover plate 45 of the hood 13. Air is supplied through the inlet opening 31 and into the lower portion of the hollow bore 28 where it passes into the slotted opening 29. The air flows horizontally through a converging area to the slotted opening 29 past the powder slot formed by the wall of the bore 28 and the conical shape divider 30 where it picks up the powder and then passes through a diverging area. The powder is fed at a uniform rate to the powder slot and the convergingdiverging areas produced by the air passing from the portion of the bore 28 adjacent the divider 30 and into the slotted opening 29 provides a slight suction or Venturi effect at the powder slot which is considered to draw the powder into the air stream. The slotted opening 29 and its powder slot between the divider 30 and the bore 28 extend for about 180 about the housing ll, and deposit of powder onto the heated nut N therefore takes place continuously over this arcuate length of travel.

In the embodiment shown, the table 10 is provided with about 60 tubes 23, each tube projecting slightly into the nut N at approximately 45. The powder is thus guided through the tube 23 to strike the internal threads of the fastener at a point slightly above the lowermost thread and the air powder flow is adjusted such that very little powder impinges upon the uppermost thread. As the tube 23 and the associated nut N rotate together over the 180 segment. a steady, rather uniform flow of powder is projected into the nut. Simultaneously, the vacuum hood l3 is drawing excess material into the hood and away from the nut N during the 180 segment. The flow of vacuum air" through the internal opening in the nut, and across the top of the nut. prevents powder from adhering to the nut except where powder impinges directly from the tube 23 onto the nut threads.

After the tube 23 and associated nut N pass from the stage of operation where the aperture 22 is in registration with the slotted opening 29 (and consequently from beneath the hood 13), there is a small arc of about 15 wherein the aperture 22 faces the outer periphery of the housing 11, and therefore the tube 23 is substan tially shut off. At about this point in the table movement, the nut confronts the leading edge of the chute l4 and while still engaged in the V-shaped slot 24 registers with the rail 51 of the chute. The nuts N are then forced into flat-to-flat engagement by continuous movement of the table 10 and are moved in a continuous stream between the inner rail 52 and outer rail 51 of the chute 14, to be removed from the table 10 to a receiving point.

During the next approximately 150 arc of rotational path, a next stage of operation takes place wherein each of the tubes 23 has its aperture 22 brought into registration with the slotted opening 34 which is connected to the chamber 33 to which a vacuum is being applied. Thus, through an arcuate distance of 150, each of the tubes 23 has a vacuum drawn on it which evacuates any excess material from the tube 23 and the aperture 22.

As may be envisioned, in providing a tube 23 which is bent upwardly at a 45 angle to distribute the pow dered material in the described manner on the internal threads of the nut N, particles of material may become impinged on the outermost surface of the tube orifice and therefore would be deposited on a subsequent nut as the nut in the heated condition was placed on the table and moved across the discharge orifice of the tube. By providing the vacuum chamber 33 and drawing the material inwardly away from the orifice of the tube 23 the material is substantially eliminated at the orifice, and the probability of depositing material at an undesirable location on a subsequent fastener is thereby substantially eliminated.

As the basic process herein carried out requires that the resin particles be forced upwardly as disclosed in the aforementioned patent application Ser. No. 314.854, the present structure uniquely solves those problems adherent in mass production of internally threaded fasteners where such process is employed. In the aforementioned patent application it was disclosed that an important feature of forcing the resin particles upwardly against the threaded surface was that those particles which are not caught on hot surfaces are borne upward by the gaseous stream and are either caught by hot surfaces of higher threads or are discharged through the upper opening portion of the nut, or other threaded fastener. If such resin particles are directed downwardly through the nut, resin could be collected only on the upper surfaces of the threads since gravity would not be available to carry resin to the thread surfaces opposite to the surfaces directly in line with the entering resin particles. Thus, in utilizing a system wherein the air entrained powder must be forced upwardly onto the threads of the fastener to achieve a process which is improved over processes heretofore known, the present invention has advantages which are numerous.

First. by keeping the tubes 23 in a clean condition, and locating the nut N precisely on the table 10 by virtue of the V-shaped slots 24, the first and last threads of the nut are maintained in clean condition so as to facilitate starting of the nut onto the male threaded fastener. The arrangement of locating and cleaning elements both minimizes any powder deposit on the threads except in the area where the patch is desired, and also eliminates any powder deposit on the external nut surfaces.

The machine being simple in nature is of a minimal cost to manufacture and has a minimal cost of parts to change over for different size nuts. Thus, when it is desirable to apply a patch to a different nut, this is accomplished by merely removing the retaining plate 36 and lifting the table 10 from the housing 11, after which a new table and related chutes and hood may be applied, accommodating a different size fastener.

Additionally, down time of the machine is minimized due to the virtual elimination of clogging of any powder passageways and jamming of nuts in the feedways.

In summary, it will be observed from the above description that the application of first powder and air pressure to the tube 23 and then a vacuum serves several purposes. First it prevents any outwardly flow of resin which might then stick to the heated nut N outside surface while the nut is being positioned onto the table 10 or removed from the table, and second the vacuum draws any excess powder from the tubes 23 to prevent a gradual powder buildup and plugging of the tubes. An additional feature of the vacuum drawn through the tube 23 is that it maintains a flow of cool air through the tubes discharge orifice to prevent a gradual temperature buildup, and the possible resultant sticking of the powder to the tube.

Another advantageous feature of the present structure is in that the location and shape of the vacuum hood 13 relative to the nut N and the air velocity also effect the powder distribution on the nut and serves to assist the feeding of the powder in the Venturi area.

A further feature which is considered to be of importance in the present structure is the manner of feeding the nuts N onto the table 10 and the subsequent removal of the nuts from the tablev As will be observed. the nuts are oriented flat-to-flat and may be visualized as a chain which meshes with the l slots 24 of the plate 27 which may be visualized as a sprocket. The to tation of the table 10 at uniform speed serves as the speed controller for the system. As each nut N approaches the lower end of the chute 12, it is lowered down over the orifice of a tube 23, and also gradually comes into meshing engagement with the V-shaped slot 24 of the plate 17. As the table 10 then rotates. the nut moves further forward. The nut is found to be guided into close engagement with the 120 slot by the outer rail 47 of the chute 12, even at speeds of approximately 600 fasteners per minute and. the centrifugal force is found to be minor on the table 10 referring only the force of gravity and the spring clips 60 where necessary to hold the nut N in place.

The chute 14 further serves to remove the train of nuts N from the table 10 by guiding them upwardly, and retaining them into engagement with the V slots 24 of the plate 17 and in linear orientation during their initial upward movement, through contact with the outer rail 51.

Thus, it may be seen that the described structure serves to achieve the various objectives of the invention through a combination of elements which coact to pro vide apparatus for the continuous manufacture of selflocking internally threaded fasteners, which apparatus is an improvement over known devices.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for applying locking patches of resilient thermoplastic resin to internally threaded articles having openings at both ends of the threaded portion comprising:

support means for receiving an internally threaded article, conduit means connected to said support means and having a first opening formed therein and directed toward that portion of the internal threads of an article supported on said support means, to which the patch is to be applied, said conduit means having a second opening at the opposite end thereof for receiving a thermoplastic resin to be deposited on the threads of the article,

discharge means for providing thermoplastic material under pressure at said second opening,

vacuum means for applying a negative pressure at said second opening, and

means for moving said support means along a predetermined path wherein said article is received on said support means, and said conduit second opening is moved into registration with said discharge means and subsequently into registration with said vacuum means.

2. The apparatus of claim 1 wherein said support means is provided with a formed cavity for receiving said article and supporting it with the axis of the threaded portion in up-and-down position and with the openings at the upper and lower ends of the threaded portion substantially uncovered. said conduit means comprising a tubular member disposed below said internally threaded article and having the portion of the member adjacent said first opening angled upwardly to locate at least a portion of said conduit first opening within the threaded portion of the article to thereby direct thermoplastic material upwardly toward a selected area of the surface of said threaded portion.

3. The apparatus of claim 1 which further includes stationary means for removing an article from said support means said removing means being located along said path of movement of said support means and downstream of said area of said discharge means registration with said conduit.

4. The apparatus of claim l which further includes inclined ramp means for feeding said internally threaded article onto said support means and heating means disposed along said inclined ramp means for raising the temperature of the threads of said article above the softening temperature of said thermoplastic material to thereby cause said material to adhere to said threads on contact therewith.

5. The apparatus of claim l which further includes vacuum hood means enveloping said article at said area of said discharge means registration with said conduit. for removing excess thermoplastic resin directed through said first opening toward the internal threads of the article.

6. The apparatus of claim 5 wherein said support member is a circular table mounted for rotation and said predetermined path is circular about the rotational axis of said table.

7. Apparatus for applying locking patches of resilient thermoplastic resin to internally threaded articles having openings at both ends of the threaded portion comprising:

support means having a plurality of cavities formed therein for receiving the internally threaded articles and supporting each article with the axis of the threaded portion in the up-anddown position.

a plurality of tubular conduits each having a first opening with at least a portion thereof disposed within the threaded portion of a respective internally threaded article, said conduits each having the portion thereof adjacent said opening directed upwardly at an angle to direct flow through said conduit opening toward a selected area ofa respective threaded article,

each of said conduits having a second opening at the opposite end thereof from said first opening,

a mixing chamber for receiving thermoplastic material and fluid pressure, and having a discharge opening formed therein.

a vacuum chamber having a negative pressure applied thereto and having an opening formed therein, and

means for moving said support means along a predetermined path wherein the second opening of each of said conduits is moved seriatim into registration with said mixing chamber discharge opening, and said vacuum chamber opening, to first cause thermoplastic resin to flow through each conduit and be applied to the threads of an internally threaded article and then to purge each of said conduits of the thermoplastic resin.

8. The apparatus of claim 7 which further includes means for depositing the internally threaded articles sequentially into said cavities of said support means located along said path just prior to said support means moving said cavity into a location wherein the second opening of the conduit associated therewith is in registration with the discharge opening of said mixing chamber.

9. The apparatus of claim 8 wherein said support means comprises a planar surface having a plurality of equally spaced openings formed therein through which said tubular conduits extend, said planar surface forming the bottom of each of said cavities upon which the bottom surface of said article rests when received in said cavity,

10. Apparatus of claim 9 wherein said articles are nuts having a hexagonal outer shape and characterized by a plurality of walls formed at right angles to said planar surface each of which forms, when taken with another, the side wall of a said cavity, the pair of walls engaging two of the hexagonal surfaces of a nut to position it with the internally threaded portion juxtaposed with a respective conduit first opening,

11. The apparatus of claim 10 wherein said means for depositing said articles into said cavities comprises an inclined ramp having its lower end disposed adjacent said planar surface of said support means and substantially aligned with the path of said support means and having side walls spaced apart a distance slightly greater than the largest dimension across the hexagonal nuts to be received on said support means, whereby said nuts are free to slide serially down said ramp with a surface in contact with a surface of a preceding and succeeding nut and a pair of surfaces being exposed for alignment with a said cavity on said support means;

12. The apparatus set forth in claim ll which further includes a vacuum hood comprised of walls substantially enveloping each of said nuts at said area of said path wherein the conduit associated with each of said nuts is disposed with its second opening in registration with said mixing chamber discharge opening,

13. Apparatus for applying locking patches of resilient thermoplastic resin to internally threaded articles having an opening at both ends of the threaded portion such as hexagonal nuts, comprising a support member rotatable about a fixed axis and having a plurality of tubular conduits disposed thereon,

each of said tubular conduits extending radially outwardly from the axis of said support member and having a portion thereof disposed within the threaded portion of a respective internally threaded article, said conduits each having the portion thereof adjacent said opening directed upwardly at an angle to direct flow through said conduit opening toward a selected area of a respective threaded article,

each of said conduits having a second opening at the opposite end thereof from said first opening,

a mixing chamber for receiving thermoplastic mate rial and fluid pressure, and having a discharge opening formed therein,

a vacuum chamber having a negative pressure applied thereto and having an opening formed therein, and

means for moving said support means along a predetermined path wherein rotating said support member whereby the second opening of each of said conduits is moved seriatim into registration with said mixing chamber discharge opening, and said vacuum chamber opening, to first cause thermoplastic resin to flow through each conduit and be applied to the threads of an internally threaded article and then to purge each of said conduits of the thermoplastic resin.

14. Apparatus for applying locking patches of resilient thermoplastic resin to internally threaded articles having an opening at both ends of the threaded portion comprising a support member rotatable about a vertical axis and having a substantially horizontal surface for receiving the articles thereon with the threaded por-- tion axis of the articles perpendicular to said surface,

a plurality of equally spaced tubular conduits extend ing radially outwardly from said support member axis and substantially disposed below said surface,

a plurality of openings formed in said surface equal in number to said conduits and located adjacent the outer periphery of said support member,

each of said conduits having an outward portion directed upwardly through a respective one of said openings to position a first conduit opening with at least a portion thereof extending above said sur face,

a second opening at the opposite end of each of said conduits,

a stationary mixing chamber disposed near the axis of said support member having a discharge opening facing radially outwardly and in registry with said conduit second openings over an arcuate portion of the rotational path of said support member,

a stationary vacuum chamber disposed near the axis of said support member and having an intake opening formed therein facing radially outwardly and in registry with said conduit second opening over an arcuate portion of the rotational path of said sup port member,

means for depositing an internally threaded article on said surface.

means adjacent said surface for locating an internally threaded article deposited thereon with an end disposed on said support member surface over a said surface ripening with a first conduit opening extending into said internally threaded portion,

means for removing an internally threaded article from said surface,

and means for rotating said support member along a path wherein each of said conduits is moved seriatim past and means for depositing an article on said surface, said arcuate portion of the rotational path where said second opening is in registration with said mixing chamber discharge opening, the arcuate portion of the path where said conduit second opening is in registration with said vacuum cham ber intake opening and adjacent said means for removing said internally threaded article.

lS. The apparatus as set forth in claim 14 wherein said articles are nuts having a hexagonal outer shape and said means for depositing an internally threaded article on said surface comprises a stationary inclined ramp having its lower end disposed adjacent said surface of said support member and substantially aligned with the path of said support member and having sidewalls spaced apart a distance slightly greater than the largest distance across the end surface of the hexagonal nut to be received on said support member and further including heating means disposed along said ramp for raising the temperature of the threads of said hexagonal nut above the softening temperature said thermoplastic material to thereby cause said material to adhere to said threads on contact therewith.

16. The apparatus of claim 14 wherein said articles are nuts having a hexagonal outer shape and said means for locating said article disposed on said support member comprises a circular plate having a plurality of V- shaped notches formed therein and disposed on said support member for rotation therewith. each of said notches forming a pair of walls adjacent one of said openings in said support member surface. and with said surface forming a cavity for receiving a pair of adjacent hexagonal surfaces ofa nut to position said nut with the internal threads disposed over said opening.

17. The apparatus of claim 14 wherein said means for removing an article from said surface comprises a stationary inclined ramp having its lower end contiguous with said surface whereby articles are fed onto said ramp and moved therealong by rotation of said support member.

18. The apparatus of claim 16 wherein said means for depositing an internally threaded article on said surface comprises a stationary inclined ramp having its lower end disposed adjacent said surface of said support member and substantially aligned with the path of said support member and having sidewalls spaced apart a distance slightly greater than the largest distance across the end surface of the hexagonal nut to be received on said support member and further including heating means disposed along said ramp for raising the temperature of the threads of said hexagonal nut above the softening temperature and thermoplastic material to thereby cause said material to adhere to said threads on contact therewith.

19. In apparatus for applying a powder and air mixture to a body wherein the means for applying the mix ture is a tubular member disposed on a movable support means and having an exit opening.

means for supplying a mixture of air under pressure and powder material to said tubular member at a point on said member remote from said exit opening. means for providing a vacuum to said tubular member at a point on said member remote from said exit opening, and

means for alternately connecting said tubular member with said air and powder supplying means and said vacuum means. said connecting means including means for moving said support means along a predetermined path.

20. The apparatus of claim 19 wherein said support means is a table mounted for rotation about a circular path.

21. In apparatus for applying a powder and air mixture wherein the means for applying the mixture is a tubular member disposed on a movable support member and having an exit opening.

means for supplying a mixture of air under pressure and powder material to said tubular member at a point on said member remote from said exit opening.

means for forcing air to flow through said tubular member. and

means for moving said support member along a predetermined path for alternately connecting said tubular member with said air and powder supplying means and with said air flow means.

said connecting means including means for moving said support member along a predetermined path.

22. The apparatus of claim 21 wherein said support member is a table mounted for rotation about a circular path.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4046106 *May 8, 1975Sep 6, 1977Long-Lok Fasteners CorporationApparatus and method of forming self-locking fastener
US4060868 *Jan 17, 1977Dec 6, 1977Usm CorporationPowder applying apparatus and process for making self-locking threaded elements
US4100882 *Oct 20, 1976Jul 18, 1978Usm CorporationApparatus for making locking nuts
US4120993 *Sep 29, 1977Oct 17, 1978Usm CorporationPlastic coating on threaded surface
US4155327 *Feb 17, 1977May 22, 1979Torkon Fastener CorporationApparatus for applying locking compound to threaded fasteners
US4259922 *Aug 25, 1977Apr 7, 1981Amerace CorporationApparatus for producing locking patches on magnetic screws
US4262038 *Oct 3, 1975Apr 14, 1981The Oakland CorporationThermoplastic resin coatings of uniform thickness on interiors of nuts
US4353941 *Sep 5, 1980Oct 12, 1982Long-Lok Fasteners CorporationPatch-type, using polyethylene terephthalate
US4888214 *Jan 28, 1988Dec 19, 1989Nylok Fastener CorporationControlled application of powder coating to internally threaded articles
US5141771 *Oct 22, 1991Aug 25, 1992Nylok Fastener CorporationPowder coating by spraying on rotatable and movable support
US5141774 *Jan 13, 1989Aug 25, 1992Prittinen Michael WMethod and apparatus for coating internal cavities of objects with fluid
US5620520 *Jun 30, 1994Apr 15, 1997Nylok Fastener CorporationApparatus for producing coated fasteners having closed ends
US6156392 *Jul 13, 1999Dec 5, 2000Nylok Fastener CorporationProcess for triboelectric application of a fluoropolymer coating to a threaded fastener
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Classifications
U.S. Classification118/50, 470/19, 118/317, 470/906, 118/50.1, 118/326, 118/308, 118/319
International ClassificationB05B7/14, B23G11/00, B05C19/00, B05B13/06, B05C13/02
Cooperative ClassificationB05B7/1477, B05B13/0609, B23G11/00, Y10S470/906
European ClassificationB05B7/14A21, B05B13/06A, B23G11/00
Legal Events
DateCodeEventDescription
May 3, 1982AS02Assignment of assignor's interest
Owner name: 50471 EAST RUSSELL SCHMIDT BLVD., MT. CLEMENS, MI.
Owner name: NYLOK FASTENER CORPORATION
Effective date: 19820430
Owner name: USM CORPORATION
May 3, 1982ASAssignment
Owner name: MICHIGAN NATIONAL BANK OF DETROIT, A NATIONAL BANK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:NYLOK FASTENER CORPORATION;REEL/FRAME:003981/0112
Owner name: NYLOK FASTENER CORPORATION; 50471 EAST RUSSELL SCH
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:USM CORPORATION;REEL/FRAME:003980/0592
Effective date: 19820430