US2321548A

US2321548A - Washer feeding means

Info

Publication number: US2321548A
Application number: US344359A
Authority: US
Inventors: Walter M Hanneman
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 1940-07-08
Filing date: 1940-07-08
Publication date: 1943-06-08
Anticipated expiration: 1960-06-08

Description

-June 8, 1943. w. M. HANNEMAN WASHER FEEDING MEANS Filed July 8. 1940 11 Sheets-Sheet l INVENTOR.

A TTORNE YS June 8, 1943. w, M, HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8, 1940 11l Sheets-Sheet 2 l\"\ 'ENTOR W. M. HANNEMAN WASHER'FEEDING MEANS Filed July 8, 1940 June 8, 1943. .2,321,548

11 Shams-Sheet 3 610 als we 49e INVENTR.

ATTORNEYJ.

i June 8, 1943. w, M. HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8. 1940 11 Sheets-Sheet 4 18% 37g rlllllmlf June 8, 1943. w. M. HANNEMAN WASHER FEEDING MEANS Filed July 8, 1940 11 Sheets-Sheet 5 S51/WWA?. @www 564 @a/ m /spa ATTORNEY.

June 8, 1943. W M HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8, 1940 11 Sheets-Sheet 6 E14 M J 34 INVENTOR.

June 8, 1943. w. M. HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8, 1940 11 Sheets-Shea?l 7 IN VENTOR.

ATTORNEYS` 'June 8, 1943 w. M. l-lumzrveAl WASHER FEEDING MEANS Filed July 8, 1940 l1 Sheets-Sheet 8 R O T N E V m ATTORNEYS.,

June 8, 1943- w. M. HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8. 1940 I 1l Sheets-Sheet 9 630 ff/Gv. ZE. l 554 0.70 /Gf 490 j/zzz.

ATTORNEYJ.

June 8, 1943.

w. M. HANNEMAN WASHER FEEDING MEANS 11 Sheecs.-Sheet` 10 Filed July 8, 1940 June 8,1943. w. M. HANNEMAN 2,321,548

WASHER FEEDING MEANS Filed July 8. 1940 11 Sheets-Sheet 11 Ill Patented June 8, 1943 WASHER FEEDING MEANS Walter M. Hanneman, Oak Park, Ill., assignor to Illinois Tool Works, Chicago, Ill., a corporation of Illinois Application July 8, 1940, Serial No. 344,359

(Cl. lil- 168) 16 Claims.

This invention relates to a machine for assembling screws and washers, and more particularly to a machine or mechanism for assembling screws and countersunk washers.

It is an object of this -invention to devise a machine or mechanism for assembling screws and washers, particularly screws and countersunk washers, which shall so anchor such a washer to a screw that the assembly may be handled thereafter as a unit.

It is a further object of this invention to devise a machine or mechanism for producing as 'an article of manufacture a unit assembly of a screw and a countersunk washer.

Countersunk washers, i. e., washers of frustoconical configuration, have a tendency to bunch up and stack while being fed to a much greater extent than flat washers, and it is therefore an important object of applicants invention to provide means for automatically feeding countersunk washers from a mass of such washers to deliver the washers each in a predetermined position.

It is also an object of this invention to devise a machine for feeding countersunk washers and screws having frustoconical heads to a mechanism assembling such screws and washers and producing a unit assembly of a countersunk Washer and a screw having a frustoconical head.

A further object of the invention is to provide va machine or mechanism for feeding or conveying countersunk washers from a receptacle or hopper containing a random mass of such washers.

It is also an object of applicants invention to devise a machine or mechanism for feeding countersunk Washers and screw elements with frustoconical heads in proper juxtaposition and alinement for assembly.

Other objects and advantages of this invention will be apparent from the following description, when taken in connection with the accompanying drawings, wher-ein certain preferred embodiments of the invention are illustrated, and wherein- Figure 1 is a fragmentary View, in side elevation, of a machine emboding my invention;

Figure 2 is a fragmentary View, in elevation, of the rear end of the machine shown in Figure 1;

Figure 3 is an enlarged fragmentary plan View of the machine shown in Figure 1;

Figure 4 is a fragmentary View in vertical section taken along the line 4 4 of Figure 3;

Figure 5 is a View in perspective of the washer hopper;

Figure 6 is an enlarged fragmentary view, in vertical section, taken substantially along the line 6-6 of Figure 3;

Figure 7 is an enlarged fragmentary View, in

vertical section, taken along the line 1 1 of Figure 3;

Figure 8 is a fragmentary generally horizontal section taken along the line 8-8 of Figure 6;

Figure 9 is a fragmentary view in elevation and partly broken away, taken along the line 9 9 of Figure 8, and showing a washer feed gate forming part of the washer feeding means;

Figure 10 is a fragmentary view, in generally horizontal section, taken along the line I-I of Figure 6;

Figure 11 is la fragmentary view, in perspective, of a washer feeding disk on part of the washer feeding means;

Figure 12 is a fragmentary View, in generally vertical section, taken along the line I2-I2 of Figure 8;

Figure 13 is a fragmentary View, in generally Vertical section, taken along the line |3-I3 of Figure 8;

Figure 14 is a fragmentary View, in vertical section, taken along the line l4-I4 of Figure 13;

Figure l5 is a fragmentary view, in perspective, of a conduit receiving excess Washers from the washer feeding means;

Figure 16 is a fragmentary View, in generally vertical section, taken substantially along the line lli-lli of Figure 3;

Figure 17 is a fragmentary view, in enlarged vertical section, taken along the line l-Il of Figure 16; Figure 18 is an enlarged fragmentary View, in section, taken along the line l8-l8 of Figure 17; Figures 19 and 20 are views, in perspective, of parts of a washer detector mechanism suspending actuation of the assembly mechanism under certain conditions;

Figure 21 is an exploded view, in perspective, of washer directing guides embodied in the machine;

Figure 22 is an enlarged fragmentary View, in vertical section, taken substantially along the line 22-22 of Figure 3;

Figure 23 is a View, in perspective, of the screw clamping jaws of the assembling mechanism shown in Figure 22;

Figure 24 is a fragmentary view, in vertical section, through the jaws illustrating clamping of a Screw by the jaws of Figure 23;

Figure 25 is a horizontal section taken along the line 25-25 of Figure 24;

Figure 26 is a view, in vertical elevation, of a screw blank and lock washer assembly prior to the rolling of the threads on the blank;

Figure 27 is a View, in vertical elevation, similar to Figure 26, but with the threads rolled on the blank and holding the washer in position thereon;

Figure 28 is a fragmentary plan View illustrating a second form of washer feeding means;

Figure 29 is a fragmentary View, in section, taken along the line 29-29 cf Figure 28;

Figure 30 is a diagrammatic View, in vertical section, showing another form of washer feeding means;

Figure 31 is a view, similar to Figure 30, for explanation of operation of the washer feeding means shown in Figure 30;

Figure 32 is a diagrammatic View, in vertical elevation, illustrating another form of washer feeding means;

Figure 33 is a View, in vertical section, take along the line 33-33 of Figure 32;

Figures 34 and 35 are enlarged fragmentary views of a portion of Figure 30 showing the operation of this form of washer feeding means;

Figure 36 is a diagrammatic View, in vertical section, of still another form of washer feeding means; and Y Figures 37 and 38 are fragmentary views, in vertical section, taken substantially along the line 31-37 of Figure 36 for illustrating the operation of the Washer feeding means of Figure 36.

As shown in Figures l toY 25, inclusive, of the drawings, a machine, which forms one embodiment of the present invention, comprises a screw thread rolling machine of standard type, such as shown in WilcoX Patents 1,584,263, of May 11, 1926, and No. 1,798,919, of March 31, 1931,f in which is provided a self-contained, self-powered attachment,

by which said machine may be adapted for the production of permanently assembled countersunk washers and screws with frustoconical heads. Auxiliary elements hereinafter described may be provided by way of refinement of this standard screw thread rolling machine to facilitate adjustment of the machine vto accommodate the attachment and improve the operation of such machine for this purpose. This attachment preferably comprises a washer hopper container or receptacle 2 (Figure 1), a washer feeding mechanism 4, an assembly mechanism 6, a driving mechanism 8, and a mounting means I0 for the washer feeding mechanism 4, the assembly mechanism 6, and driving mechanism 3.

The screw thread rolling machine comprises a main base or pedestal I2; an auxiliary base or body I4 secured or formed integral with the base I2 .and inclined at an angle of approximately thirty degrees to the horizontal; a hopper I6 for f a starter mechanism 2S; a transfer mechanism f' l 28; and a driving mechanism, parts only of which are shown, for driving the screw blank feed mechanism I3, the movable-thread rolling die 24, the starter mechanism 25, and the transfer mechanism 23.

The hopper and feed mechanism for the screw blanks As shown inI Figures 1 to 3, inclusive, the hopper I6 and feed mechanism IB for the screw blanks comprise a hopper casting or member 39 fastened to auxiliary block 32 which is provided to raise the level of the casting 3E] and the upper portion of the' guide chute 2i). The block 20 is adjustably mounted on a standard hopper supporting casting 34 Yfor adjustment at right angles tothe guide-chute 20. The casting 34 is, in turn, adjustably mounted upon a casting 35 for adjustment of the hopper casting and the upper portion of the guide chute parallel to the plane the upper portion of the guide chute verticallyv at right angles to the guide chute. The guide chute 20 which may comprise the guide bars of the standard machine rearranged in accordance with the following description, or which may comprise substitute guide bars attachable to the standard machine in the following manner, includes an upper section 38 and a lower section 43, each of which sections comprises a pair of laterally spaced bars, the bars of the upper section being indicated by` the

reference numerals

42 and 44, and the bars of the lower section being indicated by the reference numerals 46 and 43. y The upper section 33 of the guide chute 20 is carried by the hopper casting 3i?, the outer bar 42 being bolted to the hopper casting, andthe inner b-ar 44 being bolted atits upper end to a plate 53 (Figure 2) adjustably mounted as by bolts 52 passing through enlarged openings in the plate into the hopper casting Sii, which casting carries an adjusting screw 54, by which the plate 59 and the bar lilll may be adjusted relative to the casting and to and from the bar 42. The

bars

42 and 44 of the upper section are supported intermediate their ends upon a U-slflapedY bracket 56 (Figures 3 and 10) carried by a bracket 58 (Figure 10) secured to or forming a'partipf the common mounting means I9, the bar 42 being adjusted in position by a screw El) (Figure 3).

The guide bars 46 and 48 of the lower section 40 of the guide chute are in two parts (see Figure 15). The upper part is displaced horizontally and vertically from the bars of the upper section of the guide chute, as shown in Figure 3, and the two parts of the bars of the lower section are connected by curved, relatively thin strips 62 and Y$4 (Figures 3, 8, and 16) spaced apart at all points a distance equal to the spacing between the guide bars 42 and 44 and the guide bars 43 and 48. The

strips

62 and 64 are secured each at its opposite ends to the guide bars as by screws 66 (Figure 16). The guide bars 46 and 48 which form the lower section 40 of the guide chute, are mounted for relative adjust'- ment upon a guide bar supporting bracket (not shown) of the standard machine. v

A cover plate 68 (Figures 1, 3, 6, 12, and 16) overlies each section of the guide chute 29 sovas to extend over the heads of the screw units in each of the sections of this guide chute. To facilitate proper adjustment of the cover plates to accommodate screws having different size heads, there may be provided a strap, or straps, 'I0 (Figures 1, 3, and 6) for each section of the guide, the strap, or straps, 'IB being each secured to the upper guide bar as by a screw 'l2 (Figure 6). Each strap 79 carries a pin or bolt 'i4 having a concentric portion rotatably received in a circular opening in the strap and an eccentric portion 'F6 passing through an opening in the cover plate 63. A spacer .sleeve 'I3 (Figure 3) may be received on a pin or bolt i4 between the cover plate 69 and the strap 19. Upon rotation of the pin or bolt 74 a very fine adjustment ofthe cover plate relative to the guide bars may be eifected. -Screw blanks are fed from the mass in the hopper I2 onto the upper section 35V of the guide chute 29 by a reciprocating plate 26) (Figure l) slidably mounted in gudeways formed in the hopper casting. The plate 80 is operated by a driving mechanism which includes a crank disk 82 connected to the plate 80 by a link or pitman 84. In raising the hopper casting by the insertion of a block 32, it becomes necessary to substitute a pitman of shorter length, and such pitman may therefore be supplied with the attachment for the conversion of the standard thread rolling machine. A clearing device 86 of conventional structure insures an uninterrupted procession of blanks down the upper section of the guide chute and prevents clogging of the passage from the hopper. It comprises a power actuated shaft 88 driving a clearing wheel or ratchet 90 by means of pulleys 92 and belt 94. The clearing'wheel 90 is carried by the shaft 86, in turn carried by a bracket S8 adjustably secured as by bolt to the forwardly projecting arm |02 of the hopper casting, so that the clearing wheel may be adjusted by the screw |04 toward and from the guide bars 42 and 44 to accommodate screws having heads of different sizes.

The hopper and the feed mechanism for the washers As shown in Figures 1, 3, and 5 to 21, inclusive, the washer hopper and the feed mechanism for the washers comprise the hopper 2 preferably formed of sheet metal, as best shown in Figure 5. As shown in this figure, the hopper has a i bottom plate or wall |06, a forward wall |08, and a side wall |0. A portion of the bottom wall is deformed or depressed to form a relatively broad washer conveying channel or chute ||2 disposed opposite to the side wall H0. The channel ||2 has a bottom wall I4 and opposed side walls H6 and H8, the forward wall |08 of the hopper extending forwardly as at |20 to form a continuation of greater height of the side wall I6. The bottom plate or wall 06 of the hopper is inclined downwardly from the side wall l0 toward the channel H2, so that the washers dumped in the hopper will gravitate along this plate into the channel, and will then gravitate along the channel as a relatively broad stream of washers. The hopper 2 is adapted to be mounted on the hopper casting 30 for convenient angular adjustment in a vertical plane. The mounting means for the hopper comprises a strap. bar or plate |22 (Figure 3) adjustably secured as by the pivot bolt |00 to the forwardly projecting arm |02 of the hopper casting 30 and a generally U-shaped bracket |26 (Figure 5) fastened in a convenient manner to the lower end of the plate |22 and to lthe walls ||4 H8, and |20 of the washer conveying channel ||2 of the hopper.

The channel H2 conveys washers from the hopper and dumps them onto the rear surface portion of a rotating disk |28 (Figures 3, 6. 8, and 9) of the washer feed mechanism. 4. The rotating disk |28 forms part of an auxiliary hopper |30, as best shown in Figure 6, and is mounted upon the smoothly machined surface of a stationary plate |32 having an enlarged opening, in which is journaled a disk |34 fastened to the disk |28 as by the angularly spaced equal to the angle of inclination of the guide chute 20. The disk |28 has an upstanding annular circumferential ange or rim |42 having threaded angularly spaced openings `extending in the direction of the axis of the disk to receive pins or screws |44 (Figures 6 and 8) by which a ring |46 and a ring |48 are fastened in superimposed relation to the rim of the disk |23. The ring |46 forms the enclosing wall of the hopper |30. The ring |48 is interposed between the ring |46 and the rim |42 of the disc |28 and is of a thickness which is substantially greater than the thickness of the rim |46 and the rim or flange |42. The bottom annular surface |60 of the ring |48 therefore overhangs the disk |28 inwardly of its rim |42, and this surface |50 is spaced from the overhung surface of the disk a distance slightly greater than the axial height of the countersunk washers to be assembled. The upper surface |52 of the inner surface of the ring |48 is beveled or tapered downwardly so that washers collecting on this surface will tend to gravitate onto the surface of the disk |23 and will not tend to remain on the surface |52.

The rim or annular ange |42 of the disk |28 is provided with a plurality of angularly spaced openings |54 having opposed oppositely inclined walls s0 that the openings conform in configuration to the countersunk washers to be assembled. Thus, the rim |42 with the openings |54 provides a washer feed gate permitting countersunk washers properly positioned on the disk |28 with their edge of largest diameter facing upwardly and with their teeth, in the case of countersunk lock washers, extending upwardly to pass from the auxiliary hopper while at the same time preventing washers positioned on any other edge or inverted from passing from the auxiliary hopper |30.

Baffie plates |56, spaced angularly about the hopper wall |46, extend radially inwardly from the inner surface of this wall above the disk |28 and are fastened in any convenient manner, as by welding, to the rim |42. These baille plates, as the disk |28, the ring |48 and the hopper wall |46 rotate, serve to agitate the mass of washers fed to the disk along the channel |!2 so as to free the washers from each other and also serve to pick up washers in the forward lower part of the hopper and return them to the rear upper part of the hopper so that they may again gravitate along the surface of the disk |28 and, if properly positioned, fall into and pass .through the openings |54. f

disk |28, shown in Figures 6 and 8, is replaced by a like disk having a greater or less number of openings |54 of larger or smaller size depending upon the size of countersunk washers to be fed.

From the auxiliary hopper' |39, the washers passing through the openings |54 are receivedV on the smooth surface of a plate |99 (Figure 21) secured to the stationary plate |32 as by screws |92 (Figure 8). The plate |99 has a circular inner edge |94 conforming to the outer edge of the disk |28, contacting therewith and extending about the edge of the disk an angular distance which, as shown in Figure 8, is slightly greater than 90 degrees.

,Since the auxiliary hopper |36 is inclined, the washers will not of course pass out of the openings |54 above the transverse center line of the disk |28, and washers are prevented from moving out of the openings |64 except upon the plate |99 by a curved plate or retaining wall |96 secured to the stationary plate |32 and extending about the rim |42 of the disk |28 in the plane of the openings 54. The mounting means for this curved plate or retaining wall member comprises a Screw |98 loosely passing through an opening in the plate |96 and threaded into the plate |32. The coil spring 299, interposed between the outer surface of the plate |96 and the head of the screw |98, resiliently urges the plate against the rim of the disk |29. Adjacent its inner end, the curved plate |96 has an enlarged opening 292 through which passes a pin 294, carried by the plate |32. Thus, if a washer becomes jammed in an opening |54 in the rim of the disk I 26 so that it exerts an appreciable force against the inner surface of the curved plate |96, this plate may tilt or pivot outwardly about the pin 294 and against the urge of the spring 200 so that the disk will not; be held against movement by a washer so positioned but will, upon the yielding of the curved plate |96, carry the washer onto the plate I 99.

The washers slide on the edges of smallest diameter downwardly along the surface of the yplate |99 onto the upper smooth surface of. a

-bar 296 (Fig. 21) fastened to a supporting bracket as by the screws 298 and 2|9 (Fig. 8). The up- .per' surface of the bar 296 extends in the same Vplane with the surface of the plate |99 (see Figir'e 6) so that the washers may slide across the bar into the countersunk, outwardly opening recesses, notches, grooves or openings 2|2 of` a rotary washer feed disk 2|4. The recesses 2|2 are spaced angularly and in a continuous series about the periphery or circumference of the disk 2|4 (see Fig. 8). The three sides of each recess V2|2 are tapered or beveled outwardly and downwardly to conform in configuration and size to the countersunk washers to be assembled.

The disk 2|4 (see Fig. 6) extends in they same common plane with the upstanding annular rim |42 of `the feed disk |28 and the disk 2|4 has its lower surface in the same common plane with the upper surface of the plate |99 and the bar 296. A ring 2|6, having a hardened, smooth upper surface, rotatably supports the peripheral portion of the disk 2|4 and is secured in any convenient manner to a housing casting 2|8. It will Vbe noted that the ring 2|6 extends beneath the washer-receiving notches of the disk 2|4 so as hold the washers in these notches as against downward movement and guide the washers during the rotation of the disk. The upper surface lof the ring 2|6 lies in the same plane withthe and a similar pin or screw 249 (Figures 8, 12

upper surface of the bar`296 and also in the samelplane with the uppersurface of the guide bars 46 and 48 of the guide chute. The ring 2|6 is circumferentially relieved' (Figure 8) to receive the upper end portions of these guide bars 46 and 43 so that the disk 2|4 carries the Washers from the surface of the ring onto the surface of the guide bars at their upper ends.

The bar 296 has a circular edge portion 229 (Figure 21) to abut the peripheral edge of the ring 2| E, as shown in Figure 8, .and a straight edge portion 222 to abut the straight edge por-L tion -224 of the plate |99.

Guideplates or bars 226 and 228 (Figures 8 and 21) are fastened to the surface of the plate |99 and the bar 296, as by screws |92, 298 and 2|9, and form a restricted passage or throat for directing the washers toward the notched feed Y disk 2|4. The plate 226 isprovided with an in'- wardly directing guiding edge 239' for directing the washers inwardly to this restricted passage or throat. The bar 229 at'its upper edge abuts the lower edge of the curved platev |96 and is curved as at 232 to cause the washers to freely pass by the lower edge of the curved plate |96. Below the curved edge 232, which forms with the lower edge of the plate 226, the restricted passage or throat above described, the bar 229 as its inner edge inclines outwardly, as at 234;, and then forwardly along a stra-ight line, as at 236, so that the Washers maybe distributed about a greater portion of the periphery of the recessed feed disk 2|4.

' A cover plate 239, preferably of a transparent material such as Lucite, extends over the plate |99, the bar 296, the guide plate 226, the guide bar 228, and over the upper portion of the recessed feed disk 2|4, as shown in Figures 3, 6, 8, and 12 to 14. The cover plate 238 prevents washers from collecting or accumulating one upon the other as they pass along the plate |99 and the bar 296, and also prevents washers from collecting, accumulating, or passing over the surface of the recessed feed disk 2 I4. The transparency of the plate 238 permits the operator to visually observe the feeding of the washers, to take whatever steps may be necessary if the feeding of the washers is interfered with in' any way or to stop |32 and the'bar 296,.as by the pin or screw 2|9 and 13). Coil springs 242 interposed between the heads of the screws 2|9 and 249, and curved washers 244, resting on the surface of the plate 236, resiliently hold the cover'plate 238 on the guide plate 226 and guide bar 228,. The thickness of the guide plate 226 and the guide bar 228 is such that the cover plateis spaced from the plate |99 and the bar 295 a distance slightly greater than the normal axial thickness of the countersunk lock washers, and slightly above the surface of the notched feed disk 2| 4. springs 242 permit the cover plate'to be displaced or yield upwardly if a washer or object of slightly greater-than-normal thickness should pass onto plate |99, or if washers should become interlocked or pile up so as to jam between the cover plate and the plate |99. Y

The inner edge 246 (Figures ,8, 13, 14 and 21) of the bar 296 is inclined downwardly to direct excess Washers into the mouth of the vertically positionedV receptacle 248 (Figures 8, 13, 14 and 15). The curved edge surface 229 of the bar 296 is, in line with the end edge 246, notched as The coil at 258 (Figure 21), so that washers which may be interlocked with washers in the recesses of the disk 214 will be engaged by the forward edge of this notch there to be freed from the other washers and caused to fall onto the surface 246 and into the receptacle 248. The receptacle 248 may be secured to the wall of the housing casting 218, as by a screw 252 (Figure le) received in a lug 254 struck from the receptacle. The mouth of the receptacle 248 may be formed by the outwardly flaring

upper edge portions

256, 258 and 260 so as to catch washers which are tossed from the disk or from the surface of the bar 233. The receptacle 248 is connected by a tube or conduit 262 (Figures 6 and 13)` to a receptacle or pan 264 (Figure 3).

In order that the washers may not pass in a mass directly from the bottom of the channel 112 to the bottom forward part of the auxiliary hopper 1313, but will be spread over the surface of the dissk 128 at the upper end of the hopper 13D, a baffle plate 266 (Figures 3 and '1) is adjustably secured as by a screw 268 passing through a slot 210 into side extension wall 120 of the channel.

The housing casting 213 (Figure 6) is slidably mounted for adjustment toward and from the guide chute 20 on the shelf 212 (Figures 1, 4, 6, 8 and 10) of the bracket 214, which forms part of the common mounting means 18. The bottom wall 216 ofthe housing 218 is supported upon the surface of the shelf 212 and is received between the outstanding guide anges 218 of the shelf 212. Screws 288, threaded into the bottom wall 216, are received within the enlarged openings or slots 232 in the shelf 212 and retain the housing in adjusted position. An adjusting screw 283 (Figs. 8 and 10), carried by recessed block 284, secured to the shelf 212, is received in a threaded opening in an outwardly projecting lug or boss 286, formed upon the housing M8 so that upon manipulation of the screw, the housing and parts carried thereby may be moved toward and from the guide chute whereby the washers, when positioned in the upper end of the lower section of the guide chute 28 will be aligned with the common longitudinal center line of the upper and lower sections of the guide chute.

The bracket 213 is supported on the auxiliary base or body 14 by the depending reinforcing portion 288 (Fig. 6), bearing upon the shelf 268 of the auxiliary base or body, and is secured thereto as by screws 286. Bracket 214 has a depending portion 282 extending in overlapping relation to the outer vertical wall surface of the auxiliary base or body 14, and carries an adjustable set screw 284 (Figs. 1 and 4) which bears against this surface cf the auxiliary base and is secured in adjusted position as by a clamping nut 23E. Side fianges 298 of the depending portion of the bracket provide reinforcing webs for the shelf portion 212.

The recessed feed disk 214 is interposed b'etween the collar 338 (Figure 6) and a ratchet and index wheel 382, to which collar and ratchet the disk is secured for simultaneous rotation as by pins or screws 383. The disk 218, collar 388 and the ratchet 382 are journalled upon a sleeve 383 on which they are held against axial movement by an annular shoulder 383 of the sleeve, and an adjustable collar 318 threaded on the upper end of the sleeve. Springs 3i2 received in angularly spaced openings in the surface of the ratchet engage the disk 213 to raise the same from the ratchet whereby to facilitate removal of the disk upon removal of the collar 3 i8. The sleeve 386 is in turn journalled upon the upper hub portion 314 of a cam 313, which is in turn journalled upon a fixed stud shaft 3&8. The stud Shaft 313 is mounted in the boss 328 formed in the bottom wall 216 of the housing 218, and is secured thereto as by set screw 322. A worrn wheel 324 journalled on the stud shaft 318 is driven by a worm 326, keyed to a shaft 328, the worm wheel 324 being connected to the cam 313 by the key or spiine connection 338. The shaft 328 (see Figure 10) is journalled by bushing 332 in the inwardly projecting bess 334 formed with or secured to housing casting 218, and by anti-friction, roller bearing 336, bushings 333 and 348 and a sleeve 342, in an inwardly projecting boss 3413 and an outwardly projecting boss 346.

Bosses

344 and 386 may be securedto or formed upon housing casting 213. The shaft 328, with the worm 325 attached and the roller bearing 336 mounted thereon, may be inserted into the housing through an opening extending through the

bosses

344 and 336. The sleeve 362, with the bushings 333 and 36E-6 presstted thereto, is then inserted into the opening 348. This sleeve is formed with an annular ange 338 by which it may be bolted to the boss 343 as by the screws 352. The shaft 328 is driven by an electric motor 354 (Figure 1) through-a part of the driving mechanism 8. The motor 354 is mounted upon a depending arm 356 of a bracket 358 (Figures l and 6) bolted to the bracket 214 as by screws 338 received in threaded openings in a rearwardly projecting flange 362 (Figs. l and 4) of the bracket 214. The motor is connected to the shaft 328 by a belt 364 (Figures l and 10) passing about a pulley 366 secured to the motor shaft, and a pulley 338 secured to the outer end of the shaft 328. f

The ratchet wheel or index plate 332 is intermittently driven by a dog lor pawl 318 (Figure 10)'journalled at one end on a pivot pin 312. Pin 312 is in turn pivotally received inY one end of a lever 314, the hub portion 313 (Figures 6 and 10) of which is journalledluponv a-cylindrical bearing member or sleeve 318, having an enlarged adjusting 'head 386 of preferably hexagonalV configuration. TheV bearing 3134 is eccentrically bored to receive 'amounting stud 332 threaded into the bottom wall 216 of thev housing casting 218, and vhas an enlarged slotted head 384 'to retainthe bearing 318 against'axial movement and to permit the bearing to be adjusted eccentrically about the axis of the stud 382 by applying a suitable tool to the adjusting head380 of the bearing. The hub portion 316 of the lever 314 is also formed with 'angularly spaced

arms

386 and 388,. the arm 338 carrying a roller or cam follower 390engaging the surface Vof the cam 316. The roller or cam follower'338 is held in engagement with the surface of the cam 316, and the tooth of the pawl l313 is held in engagement with the tooth of the ratchet wheel or index plate 382 by a coil spring 332 interposed lbetween the head 384 of a rod 396, anda bracket 398 secured to the housing casting 218. The rod 388 is 'slidably mounted in `an opening in the bracket 388, and its .head 394 bears against a block 1583' formed :on lthe outer end of the lever arm 388.` The levervarm 383 passes from the housingcasting 213 through a circumferential slot 482 (Figure 6); i y Y rA coil spring 484 is anchored at one end, as by the pin 486, to a projecting lug .488 formed upon the p awl, 310, the other end of the coil spring 484 being anchored, as by a pin 416, to an indexing pawl or dog 412. The indexing pawl or dog 412 is pivotally mounted at one end upon a bearing member or sleeve 414 eccentrically bored to receive the threaded mounting stud 416 having an enlarged slotted head retaining the bearing member against axial movement and detachably securing the bearing member to the bottom wall 216 of the housing 218. The peripheral surface of the bearing member 414 beneath the pawl 412 may be provided with tool receiving slots or openings by which the. bearing member maybe rotated about the eccentric axis of the mounting stud so as to bring the tooth of the indexing pawl into proper mating relation with teeth of the ratchet or index wheel 3112.

The worm wheel V324, which drives the cani 316, also through this cam drives a second cam 418 (Figure 6) which drives the'assembly mechanism 6, as will subsequently appear. The cam 418 is journalled on the upper end of the fixed stud shaft 318, andis held against axial move ment on the stud shaft by resting at its lower surface upon the hub portion 314 of the cam 316 and the sleeve 306, and by la screw or bolt 420 having an annular flange or washer 422 overlying the upper end of the stud shaft and the hub portion of the cam I413. The screw 420 is centrally bored, as at 424, throughout its entire length to permit lubricant to be injected into the axial opening 426 in the stud shaft, which axial opening communicates with a diametrical opening 428 by which the `lubricant passes tola Y radial opening 430 in the hub 314 of the cam 316, and an axial surface groove 432 in the stud shaft 318. By this last groove, lubricantis supplied to the internal bearing surface of the worm Wheel 334 and the cam 316. The radial opening 436 communicates with a surface groove 434 in the hub portion 314 of the cam 316, by which groove the lubricant is supplied to the external and internal bearing portion of the cam and the' sleeve 366.

Adjustable means are provided forfacilitating removal of the washers'from thesurface of the ring 216 to the surface of the guide bars 46jand 48, and for facilitating the return of thewashlers from the upper surface of the guide bars to the supper surface ofthe ring if noscrew blank is fe'd by the assembly mechanism 6 int'o assembled relation with a washer at the upper end in these guide bars. This means comprises a ywedge 436 (Figure 10) 4slidably mounted in a groove in the ring 216 so that the surface of the wedge lies flush with the surface of the ring and the surfaces of the guide bars 46 and 48, and this wedge is adjustably secured to an inwardly vprojecting portion of the wall of the tubular housing 218 as by a screw 438 secured to this inwardly projecting wall portion,A and received in van elongated slot '440 in the wedge 436. The wedge 436 provides 'readily adjustable ymeans lfor supporting the washers as they move from thesurfac'e ofthe ring 216 to the surfaces of the guide bars 46 and 48, and compensates for the usual manufacturing tolerances. Wedge plate 436 also facilitates adjustment of the washer feeding mechanism to accommodate washers of different sizes,for as theV external diameter of the washers increases, the1 housing 218 with the ring'216 and the disk'214` must be adjusted outwardly relative to the inner guide bar 48. A plate 44|, adjustablysecured to an inwardly projecting portion of the vtubular wall of thehousing 218, as by screws 442 received Vin elongated slots 444y 'in this plate,`abut's the Y blank, the resilient strip will strike it and force outer edge' of the guide barf46 and has its upper surface flush with the upper surfaces of theA bars 46 and 43 .and the ring 216. This plate 441 provides readily adjustable means for facilitating the movement of washers from the upper surfaces of the guide bars to the surface of the ring 216 so that washers with which screws have not been assembled at the upper ends of the `guide barsmay be carried off of the surface of the guide bars and dropped into the forward part of the receptacle 264 (see Figure `3). Y

The auxiliary hopper 138 vvwith its operating mechanism is mounted upon a rearwardly extending arm or shelf A446 (Figures 1, 6, 10 and 12) of the bracket 358 of the common mounting means 10, as by screws 448 vpassing through the shelf l446 and receivedin the threaded angularly spaced bosses 168 ofthe mechanism housing 162. The stud shaft,v 183,Y upon .which idler pulley 186 is journalled, is mountedin a boss 41H3' (Figure 10) formed on the lshelf 446, the shaft being fixed by a set screw 411.2. The pulley 186 is driven by 'a belt 414 (Figures 1,' 6 and 10) which passes about this pulley and about apulley k416 (Figure l0) secured to the motor shaft.

Means is provided for preventing any washer with which a screw blank has not been assembled from passing downV the lower section 46 of the guide chute and for rejecting such washer from this'section of the guide chute. This means comprises a resilient strip 418 (Figures 3, 8, 10

and 16) carried Vby a block 488 fastened to the upper portion of the guide bar 48 as by the screw 482. The strip 418 extends across the lower section of the guide chute, as shown in Figure'B, so as to engage the periphery of the washerpassing down the guide chute. If the lwasher be assembled with a screw blank, thestrip will readily y yield to permit'the assembled screw and washer to pass downwardly ofthe guide chute, but'if the washer be not assembled with the screw it into the washer .receiving pan 264.

The washer feeding means ormechanism 4 operates as follows:

` llfashers are dumped into the hopper 2 (Fig.-

- 3) and move bygravity into the feed channel 112 of the hopper, along which they gravitate in .abroad stream onto the surfacevoflthe washer feedV disk 12,8. VrIhe baffle plate 266 holds back the stream or mass o-f washers atthe bottom of the channeland causesV them to spread out on the Ysurface ofthe disk 128 and be carried upwardly out of the mass by the clockwise rotation of the disk.

Sorne'of the washers pass almost immediately Y into 'openings 154 (Figs. 6 Vand 8) the rim 142 of the disk 128, while, others, probably the greater percentage, slide or gravitate downwardly along the surface of the diskand pass'into and through the openings 1.54 at the forward Alower part yof the auxiliary hopper 130. k*The baille plates 156, which extend between theV ringV .-143 Vand the disk 128, serve as washer agitating vmeans and as means for returning vwashers which have not passed through the openings 154 at the forward lower part ofthe hopper backAto. Vthe upper part' of therhcpper. .From the auxiliary hopper 138, washers pass through the openings 154 in an arcuate range of slightly .greater than degrees, and are directed by the guidel plate 226, Vthe guide bar 228, and the'forward end of the arcuate bar 156 along the smooth hardened surface of the platelS and'onto the .bar 266. The washers Vgravitate across the h'ardened'surface of the bar 255 into the countersunk peripheral recesses, notches, or openings 212 of the rotary feed disk 214, by which they are carried upon the upper surface of the ring 216 to the upper edge of the guide bars 45 and 48 of the lower section 40 of the guide chute 20, and are positioned on these guide bars with the center aperture of each washer aligned with the common longitudinal center line of the upper guide bars 42 and 44 and the upper portions of the lower guide bars 45 and 48. An excess accumulation of washers on the surface ofthe bar 245 may cause certain of the washers to engage washers seated in the recesses of the disk 214, and these excess washers so engaged will thereby be carried along the surface of the bar to its beveled end edge 246, down which such washers will gravitate into thereceptacle 245 and thence through the tube 252 to the washer-receiving pan or receptacle 264. Washers which may have their teeth interlocked with vwashers seated in the recesses of the feed disk 214 will be carried past the notched part 256 of the bar 255 and will be engaged by an edge of the notch so that as the disk continues to rotate, the washers will be separated and the excess washer fall onto the washer'discharging surface 245 of the bar 255.

Interrupted or intermittent movement of the washer feed disk 214 is eiected by the cam 316 (Figs. 6 and 10) and the spring 392. As the high point of the cam approaches the cam roller 590, the lever 314 is caused to move in a countercloc'kwise direction (as seen in Figure 10) and the pawl 31E! is moved against the action of the spring 392 in a direction to move freely about attached to the ratchet precisely at the point at which the center of the notch 'M2 of the disk is held at the point of assembly.

The assembly mechanism As shown in Figures 1, 3, 4, 8, l0, 16, 17, ,i8 and 22 to 25, the assembly mechanism comprises a strap or bracket 484 (Fig. l) of substantially inverted U-shape, detachably secured to the flanges 218 of the supporting bracket 214. A bracket 485 (Figs. l, 3 and 4) is mounted on the bracket 424 for adjustment toward and from guide chute 25, the bracket 435 being secured to the bracket or strap 484, as by screws 488, carried by the strap and received in an enlarged opening or slot in the base of the bracket 486. An assembly head 491i is carried by the outer tubular end portion 492 (Figures 3, 4 and 22) of a casting or bracket 454 having arms 495 diverging from the tubular portion 492 and terminating in parallel arm portions 499 (Figure 3),

, embracing the bracket 455 and mounted thereon in the tubular portion 492 of the head, and ernbracing a slide rod or plunger 558 relatively slidable within the sleeve 595. The plunger 558 is connected by the coupling 51D to a rod 512. The coupling 51D has an axially extending tongue 514 received in a mating diametrical slot in the upper portion of the plunger 508. The rod 5i2 passes through a cap nut 516, received on the threaded upper end of the tube or sleeve 555, the rod 512 carrying at its upper end adjustable movement limiting and clamping nuts 558 and 525. The nut 518 in the upper position of the assembly head is spaced a predetermined distance above the cap nut 515. Below the cap nut f- 516, the tubeV or sleeve 595 carries an adjustable movement limiting and clamping nut or collar 522 which is adapted upon the downward movement of the assembly to engage a cushioning washer 524 encircling the tube 596, and positioned upon a cap nut 529 carried by the upper end of the tubular portion 492 and clamped in adjusted position by the nut or collar 523. A coil spring 539 embraces the rod 512 and is housed within the upper portion of the tube 555, the spring 539 being interposed between the coupling 519 and the cap nut 555. Upward movement of the tube 555 relative to the tubular por.- tion 452 is limited by the engagement of the shoulder 532 of the tube with the cap nut 525.

Adjacent its lower portion, the tube 555 is provided with an internal thread mating with an external thread of a sleeve or tubular member 534. The sleeve or tubular member 534 is provided with diametrically disposed, axially extending slots or grooves 535 receiving the shank portions 535 of complementary jaw members 549. The jaw members 545 are provided at their lower ends with jaws 542 (Figures 23 to 25) adapted to receive and support the truste-conical heads of the screw blanks successively fed to the members. The jaws 542 have notches 544 for receiving and clamping the Shanks ofv the screw blanks to the jaw members. As will be seen from Figure 25, the shape of the notches 544 is such that the outer edges 545 ,are spaced apart a lesser distance than the inner edges 548 so that when the inner edges are spaced apart sutilciently to permit the shank of a screw blank to pass therebetween, the edges 545 are lspaced apart a distance less than the diameter of the screw shank and prevent the screw from falling through the jaws from the upper section of the guide chute. Each jaw member 540 is fulcrumed on the sleeve 534 by a protuberance 555 received in a notch extending inwardly .from the bottom of the slot 535 (Fig. 22). The jaw members are held in assembled position with the sleeve 534 by a spiral spring 552 having its opposite, outwardly bent ends 554 received in open.- ings 556 in the jaw members.

A sleeve 55B, whichvv determines the opening movement of the jaw members as the assembly head approaches its upper limit of movement, is secured to the iixed tubular portion 492 for micrometric adjustment relative thereto by opposed set screws 559 and 552, having frusto-conical end portions received in frusto-conical open- Iings or notches 554 and 55B, respectively, in the bers, causes the jaw members to fulcrum relative to the sleeve 534 about protuberances' 550,- and thereby move the jaws apar-t a predetermined distance to the proper position" to receive "the foremost screw blank from the upper section 38 of the guide chute 28. The jaw members 548 are moved to closed position by a coil .spring 512 embracing the lower portion of the sleeve 534, and a sleeve 4 slidably mounted on 'the sleeve 534 and interposed between an .annular flange 516 of the sleeve 534 and an 'annular flange 518 of the sleeve 514. YThe annular flange 51S bears upon the upper edges of 'the heads 519 of the jaw members 548, outwardlyr of thefuloruming protuberances 559, so that the jaw members when out of engagement with the tapered 'surface 568 of the fixed sleeve 558 are urged toward each other to clamp .the screw blank between the jaws 540. The jaw members are moved to full open position as the assembly head approaches its lower limit of movement rby an adjustable stop provided by a nutor collar 589 on the lower end of the fixed tubular portion 492,

Aand held in adjusted position by the clamping nut or collar 582. The heads 513 of the jaw members are provided with outwardly extending lugs or arms 584 which are received in slots or openings 586 in the lower part of the tubular portion 492. i

As the assembly head approaches itsV lowe limit of movement, the arms v584 ofthe jaw members engage the upper edge of the collar or nut 588, and consequently as the sleeve 534 continues its downward movement,V the jaw members are rotated oppositely to full open position, releasing the shank of the screw element and permitting the head thereof to pass downwardly between the jaws 542. The reduced part or plunger 538 of the plunger rod 598 is Vslidably received in the reduced Abore of the lower Vportion 598 of the sleeve 534;

The rod'588 ex-Y tends substantially below the sleeve 534 and in the upper position of the assembly headv is spaced a slight distance above the heado'f the screw resting upon the jaws 542. The distance between this rod and the head of vthe screw is substantially equal to the distance betweenthe nut 5l8 on the rod 5|2 and the cap nut Y5I'i when vthe assembly head is in its upper-limit of movement.'

The jaws 542 are provided with oppositely tapering surfaces 592 forming seats for the frusto-conical head of the screw `to be assembled.

The assembly head is operated by the prelviously mentioned cam 4l8 (Figs. l, 3, 4, v5 ,and

.8) mounted on the upper end `of the` stationary stud shaft 3|8 (Figure 6) vof the washer feeding means 4, the cam 4l8 being driven by the cam 3l6 as previously described. The Vcam 418 is formed with an upper cam surface having two active portions, one of which raises aplunger rod 594 (Figure 4) and the other of which permits lowering of the plunger rod, and two dwell portions, one of which maintains the plunger in its upper position lfor a given period and the other of which allows the plunger t'o remain in its lower position for another given period.

The plunger rod 594 is slidably mounted inY a bushing formed with the shelf portion 598 'integrally with the web 584 of the assembly head support casting 494. A' lever .689 pivotally mounted on the pin 500 carried by the bracket 486. is raised by the plunger` 584 through an adjustable set screw 682 secured Vin adjusted.

bya coilspring 606 anchored at one end to a pin 698' carried bylan arm 496 of the head sup'- po'rting casting `v494 and at its other 'end the spring is anchored to Yalpin BIO projecting inwardly in a tube 6l2, press-fitted or otherwise secured at its lower end to the lever 600. 'The tube 6l2 permits the u se Vcfa relatively large spring r656, notwithstanding the relatively close position ofthe lever with respect to the casting 494. tted'into the free end of the lever 600 and is seated in a slot SIGY in the enlarged portion of the plunger or rod V508. The head (H8 ofthe pinr 6I4 may be formed with flat side Asurfaces and the slot tilt may therefore take a rectangular configuration. The pin 6M passes through relatively elongated yslots 529 and v622y in the tubular portion 492 Vof the head supporting casting 494 and the tube or sleeve-586 respectively.

|The assembly mechanism operates as follows:

The cam 3l6A (Figures 6 and 10) of the Washer feeding ymeans is drivenin a clockwise direction as seen in Figure l0 to elecifthrough the spring 392 interrupted or intermittent movements of the washer feeding disc 2I4 in a counterclockf wise direction. Each revolution of the cam 3l6 effects movement of the washer feeding disc an angular distance corresponding to the distance between successive Washer receiving notches. For each revolution of the cam 3l6, the cam H8 also makes a Single revolution, and since qpositionso that the springv 696 carries the lever V`with its ball-headed pin 614 to its lowerl prosition. In moving from its:V upper to its lower position, this lever 690 by means of the pin 614 first causesV the plunger 588 to move downwardly a limited distance relative to the tube or sleeve 585 until the plunger rod 588 engages the head of a screw Vblank in the jaw member 540, or until the nut 5l8 engages .the ycap nut 5|6.

The tube 556 ythereafter ,moves downwardly with Vthepl'unger 598 and the jaw members 540.

rlower section of the guide chute. K

movement of the jaw membersl may basogprog; Y Y vportioned that in its continued `downward"move:.

In the preliminary portion of the downward movement offthe jaw members, their heads '519 move along theinternal tapered surface 558 v'of the sleeve 558 and coil spring 574 accordingly moves `these jaw members toward each other so Athatfthe shank of the screw blank is clampedin uthe' notches 544 of the jaws 542.

As the lever '669 approaches its lower limit 4of movement, the arms 584 of the jaw members engage th'e stop collar 580 and as 'the plunger rod 558 and the tube 534 continue their downward f position, the shank lof the screw blank having l meanwhile been insertedA through a countersunkwasher positioned at the upper end of ther."

upper parts of the guide bars 45 and V48 ofthe This opening,

ment, the plunger 588 'forces th'egrh ad screw between thev head' centerin A'ball-headed pin 6 I4 (Figure 22) is press'- washer detecting mechanism subsequently described.

A screw blank having been assembled with a washer, the cam 4I8 causes a raising of the plunger 594 and thereby moves the lever 558 in an upward direction and tensions the spring 658. It is during the consequent upward movement of the assembly head, or during the time the assembly head is resting in its upper position, that the washer feeding disc is moved to carry the assembled screw blank and washer from the point of assembly and to position another washer at the point of assembly. The plunger 588 moves upwardly with the lever B and the upward movement of the plunger is transmitted to the tube 506 through the coupling 5| 8 and the spring 538. As the arms 584 of the jaw members 54) move away from the stop collar 585, they are moved to closed position by the spring 552. As the tube 508 approaches its upper limit of movement, as determined by the engagement of the shoulder 532 with the cap nut 526, the heads 510 of the jaw members engage the internal tapered surface 558 of the sleeve 558 and are accordingly moved partially to open position to receive the foremost screw blank on the lower end of the upper section 38 of the guide chute 20. The tube 586 completes its upward movement just before the lever 688 reaches its upper position as determined by the cam H8 and the adjustable set screw 682, and accordingly the plunger 508 continues to move a limited distance relative to the tube 505 so as to clear the head of the screw blank and permit free gravitational movement of the screw blank into position between the jaws The coupling 5I!) permits downward movement of the plunger 588 relative to the rod 512 after the nut 5|8 has engaged the cap nut 51.6 so as to contact screw heads smaller than normal and also permits the plunger 568 after the tube 505 and the sleeve 534 have been stopped by the engagement of the arms 534 of the jaw members with the limit collar 580 so that the plunger may continue to push downwardly on the screw blank after the jaws have been opened.

Means are provided in cooperative association with the assembly mechanism and the washer feeding means for preventing the feeding of a screw blank if a washer has not been positioned at the point of assembly, that is, if a recess -2l2 arriving at the point of assembly does not enclose a washer. This means also acts to center the frusto-conical head of a screw in the countersunk washer into which it has been telescoped.

This means comprises a block 624 (Figures 10, 13 and 18) secured to the bracket 398 as by the stud or bolt B25. A spacer plate 628 (Figure 19) overlies the block 624 and Vis interposed between the block and a relatively thin bell crank lever S30 (Figure 20). The spacing plate 628 and the bell crank lever 630 are journalled with the block 624 on the stud or bolt 626. The spacer plate 528 has

arms

632 and 534, and the bell crank lever has similar arms 636 and 538, all of which arms are secured to the block as by screws 548. The ends of the arms 836 and 538 of the lever 638 are bent under as at 642 and 644 (Figure 20) to space the body of the lever from the spacing plate 528. The lever 530 also has an arm 545 to which at its free edge is riveted on the underside and inwardly from its inner edge 648 a washer engaging block 558. At its outer end the edge. 648 of the lever arm 645 is beveled or tapered as at 552 to conform to the taper of the frusto-conical head of the screw blank to be assembled, A coil spring 554 is seated in an opening Vi555 in the end 658 of the block 624 and in a similar opening or recess in the annular wall of the mechanism housing 2'I'8.

A plate B60, generally L-shaped in elevation (as seen in Figure 17), is fastened to the lower end of the outer guide bar 42 of the upper section of the guide chute and its lateral flange 652 overlies the recessed washer feeding disc 2I4 as shown in Figures 17 and 18. At the assembly point, that is, beneath the assembly head, the

flange 662 is cut away as at 664 so as to permit the shank of the screw blank to be inserted in a washer in a peripheral notch of the disc 2 I4. The forward end of the inner edge of the flange 652 is tapered as at 665 to engage the frusto-conical screw head and in cooperation with the tapered edge 852 of the'lever 630 center thefscrew precisely in relation to the countersunk washer. The flange 662 'lies in the common plane with the transparent cover plate 238 and therefore prevents washers from tilting in the recesses of the disc. 2l4 as the washers pass from beneath the cover plate to the assembly point.

If a washer is not positioned in a recess 212 when the recess is brought to the assembly point, the spring 554 causes the block 624 to move in a counterclockwise direction as seen in Figure 18, and through this block causes a similar counterclockwise movement of the lever 635. The washer detecting block 550 therefore moves through the unoccupied recess SI2 and the arm 646 of the lever extends in the path of movement of a screw as it is carried downwardly by the assembly head. This stops the downward movement of the screw and through the screw the downward movement ofthe plunger 508 and the lever 655, and holds the* assembly mechanism against operation by the spring 685 (Figure 4) Since the jaw members 540 are thus stopped before they engage the limit collar 58B, the jaws remain in closed position clamping the shank of the screw blank. When a high point of the cam 4H? again ccmesunder the plunger rod 594, the assembly head is moved upwardly to its original position with the screw-blank still resting in the jaw members. It should be observed that the edge 658 of the washer detecting block 650 is beveled or tapered (Figures 18 and 20) and consequentlyupon the next movement'of the recessed washer feed disc 2|4', the edge of the disc will enga-ge this surface 663 and move the lever 63B and the block 524 in a clockwisedirection as seen in Figure 18. The spring l654 has of course a sulficient tension to cause the block 624 and the lever 63B to move in a counterclockwise direction when not stopped by a washer at the assembly point, but at the same time, the tension of the spring is such that it does not impose by engagement of the block i550 with the edge of the disc 2M a Asubstantial drag upon the disc. It should also be noted that the flange 651. of the L-shaped plate 555 overlies the rim of the washer at the assembly point as shownin Figure 17 and thereby prevents tilting of the washer under the pressure of the spring 554 acting on the washer through the block 550. 4

The thread rolling mechanism, the transfer mechanism, and the starter mechanism These mechanisms which form part of a standard thread rolling machine may be conventional in structure and therefore it suffices to note briefly that the fixed die 22 of the thread rolling,r