US2967444A

US2967444A - Thread rolling machines

Info

Publication number: US2967444A
Application number: US513085A
Authority: US
Inventors: Elmer E Hallberg; Ralph S Litterst
Original assignee: Rockford Machine Tool Co
Current assignee: Rockford Machine Tool Co
Priority date: 1955-06-03
Filing date: 1955-06-03
Publication date: 1961-01-10
Anticipated expiration: 1978-01-10

Description

Jan. 10, 1961 Filed 'June s, 1955 E. E, HALLBERG ETAL 2,967,444

THREAD ROLLING MACHINES 6 Sheets-Sheet 1 INVENTORS.

Jan- 10, 1961 E. E. HALLBERG ETAL 2,967,444

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THREAD ROLLING MACHINES Filed June 5, 1955 e sheets-sheet 5 INVENToRs. E me rf Hallbefg Jan- 10 1961 E. E. HALLBERG ETAL 2,967,444

THREAD ROLLING MACHINES 6 Sheets-Sheet 6 Filed June 3, 1955 INVENTORS.

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www1 @Sw United States Patent() THREAD ROLLING MACHINES Elmer E. Hallberg and Ralph S. Litterst, Rockford, Ill., assignors to Rockford Machine Tool Co., a corporation of Illinois Filed June 3, 1955, Ser. No. 513,085

4 Claims. (Cl. 80-8) This invention relates to machine tools and more particularly to machines for rolling screw threads, splines, or other similar formations on substantially cylindrical workpieces, and has for a general object the provision of improvements in such machines.

It is also an object of the invention to provide a new and improved thread rolling machine including cooperating ram and compression dies having flat faces arranged in generally parallel relationship with each other, means mounting the ram die for reciprocal movement in the direction of its length, means mounting the compression die for reciprocal movement in a direction perpendicular to its operating face, novel means for moving the compression die toward the path of movement of the ram die, and novel means for feeding a blank workpiece into operative relationship between the edges of the ram and carriage dies.

Another object of the invention is to provide a thread rolling apparatus having a reciprocable ram die anda cooperating carriage die provided with serrated faces arranged in parallel relationship for rolling a blank workpiece therebetween, and novel means for moving the carriage die toward the ram die during rolling to effect lthe formation of screw threads on the workpiece.

A further object is to provide a new and improved thread rolling machine of the type described in the preceding paragraph including a movably mounted wedge engaging an inclined surface on the carriage die supporting means for shifting the carriage die toward the path of the reciprocable ram die.

Another object is to provide a new and improved thread rolling machine of the type described in the preceding paragraph including a hydraulic piston and cylinder device for reciprocating the wedge to control the movement of the carriage die toward and away from the ram die, and adjustable stop means for limiting movement of the wedge.

It is also an object of the invention to provide a thread rolling apparatus having a compression die and a cooperating ram die arranged in parallelA relationship thereto and adapted to be moved between a`starting position in which the leading edge of the ram die is adjacent the trailing edge of the carriage die and an ejection position in which the trailing edge of the ram die is adjacent the leading edge of the carriage die, and novel mechanism for feeding a blank workpiece into a position between the edges of the dies at the starting position where it will be picked up on movement of the ram die past the carriage die.

A further object is to provide a new and improved thread rolling machine of the type described in the preceding paragraph in which the feeding mechanism includes a trough extending angularly toward the pickup position to guide and support a workpiece, and a reciprocable pusher adapted to push a workpiece from a position in which it has been deposited in the trough to the pickup position.

Other objects and advantages will become readily ap- Mice 2 parent from the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a perspective view of the entire machine, with the ram die in an advanced position;

Figure 2 is a fragmentary top plan View of the machine, with the ram die retracted;

Figure 3 is an enlarged fragmentary top plan view showing the details of the blank feeding mechanism;

Figure 4 is an enlarged elevational view taken substantially along the line 4-4 of Figure 2 and showing the carriage die and its mounting;

Figure 5 is a sectional view taken along the line 5-5 of Figure 4 and showing the pivotal mounting for the blank holding member associated with the feed trough;

Figure 6 is a sectional view taken on the line 6-6 of Figure 4 and showing the details of the mounting for the carriage die and the ram die; v

Figure 7 is an enlarged fragmentary end elevational view taken substantially on the line 7-7 of Figure 3; and

Figure 8 is an enlarged fragmentary sectional view taken substantially on the line 8-8 of Figure 3 and showing the details of construction for the feed trough'.

The invention further resides in the combination, conf struction and arrangement of parts illustrated in the accompanying drawings, and while we have shown therein a preferred embodiment we wish it understood that the same is susceptible of modification and change within the scope of the appended claims.

Referring now to Figures 1, 2 and 3, the invention is embodied in a machine which includes a compression or.

carriage die 2, a ram die 5, and a blank feeding mechanism 8 which delivers a generally cylindrical blank workpiece W into a position where it is adapted to be rolled between the dies to form screw threads thereon. The dies Z and 5 are provided with generally parallel vertically extending faces which are serrated in complementary cross-sectional configuration to the cross-sectional configuration of threads to be formed on the workpieces. The ram die 5 is mounted for horizontal movement longitudinally, back and forth past the carriage die 2 to roll a workpiece along the face of the carriage die. The carriage die is mounted for movement back and forth in a direction perpendicular to its serrated face, that is, toward and away from the path of the ram die during rolling to compress the workpiece between therdies to elect the formation of screw threads on the workpiece.

The ram die is mounted for movement from `a starting position wherein its leading edge 6 is slightly behind the trailing edge 3 of the carriage die to an ejection position where its trailing edge 7 is slightly in advance of the leading edge 4 of the carriage die.

The feeding mechanism 8 is adapted to deliver a blank workpiece from a position W1 where it is depositedby an operator or by an automatic device to a position W2 where it is adapted to be picked up on movement of the ram die 5 past the carriage die 2. The workpiece is rolled along the carriage die and past its leading edge where it is ejected to fall into a trough 10 beneath which Va portable container may be placed to receive the nished workpieces.

In order to mount the carriage die forthe desired operation, a suitable base structure includes a bed 12 having horizontal guide ways 13 which extend perpendicular to the path of movement of the ram die. A carriage 15 is mounted on the guide ways 13 for adjustment toward and away from the path of the ram die. Referring now particularly to Figure 6, in order to form a housing for the structure which mounts the carriage die, the carriage 15 includes a horizontally disposed base member 16 which extends to a position immediately subjacent the path of the ram die 5. A member 17 extends vertically upward ,from a mid-portion of the base member 16 and has a backup plate 18 secured thereto by means such as screws indicated at 19. A cover plate 20 extends across the backup plate 18 and, as seen in Figure 4, is secured by screws 21 to `vertically extending frame members 22 and 23 at opposite sides of the carriage. The frame members 22 and 23 are fastened in their bottom ends by screws 25 to laterally extending

portions

26 and 27 of the base member 16. The laterally extending

portions

26 and 27 form ways resting on the guide ways 13 of the carriage bed 12. The

members

16, 18, 20, 22 and 23 form a housing for the structure which mounts the carriage die.

A carriage die supporting member 29 is slidably guided by hardened

bearing plates

30, 31 and 32 fastened t0 the

members

16, 22, and 23 by means such as screws 33. The die supporting member 29 is recessed in the face portion adjacent the ram die to form a carriage die receiving cavity defined by a supporting ledge 35 at vthe bottom, a vertically extending wall 36 at one end of the supporting member 29, and a clamping gib 37 at the other end. The carriage die is clamped in the supporting member at its ends between the wall 36 and the gib 37. At the bottom, the carriage die is rested on frangible elements 39 supported on the ledge 35. At the top, the die is held by frangible hook shaped clamps 40 secured to the die supporting member 29. The

frangible clamping members

39 and 40 are constructed of a predetermined strength and are designed to rupture in the event that abnormal forces are directed vertically against the die, as by a jammed workpiece, for example.

The carriage die is continually biased away from the path of the ram die by means of a pair of bolts 45 (Figures 4 and 6) having threaded end portions which receive circular nuts 46 recessed in the face of thecarriage die supporting member 29. Recesses y47 are provided in the face of the nuts 46 to receive a tool for removal. Each of the bolts 45 passes through a bore 49 in the member 29 and is provided with a head 50 against which a spring 51 bears to draw the supporting member 29 inwardly, away from the path of the ram die. Each of the springs 51 is housed in a Ycylinder 52 fitted to a spacer plate 55 secured to the backup plate 18.

In order to move Vthe carriage die supporting member toward the path of the ram die against the bias of the springs 51 to compress a blank workpiece between the dies, an actuating wedge 60 is slidably mounted between the spacer plate 55 and a spacer plate 61,secured to the inclined rear face of the carriage die supporting member 29. Each of the spacer plates 55 and 61 is provided with roller bearings 62 which engage opposite surfaces of the wedge 60 to permit its movement freely. Obviously, on movement of the wedge 60 downwardly, the carriage die supporting member 29 will be moved toward the ram die and on movement of the wedge upwardly, the member 29 will be withdrawn by force of the springs 51.

Reciprocal movement of the wedge 60 is effected by means of a hydraulic piston and cylinder device including a cylinder 65 fastened to a support 66 secured by screws 67 to the carriage 15. A piston rod 68 extending from the cylinder 65 is connected to a connecting rod 69 which is threaded into the wedge 60. It seems apparent that 'uid may be admitted to opposite end portions vof the cylinder 65 to move the wedge 60 back and forth.

Utilization of a wedge as the actuating means for mov- `ing the carriage die is extremely effective in perfecting the nicety of control over the carriage die which is necessaryin forming threads of a high quality. Obviously, a large amount of force must be exerted by the carriage die to form the threads, and yet only the slightestmovement of the carriage die toward the ram die isnecessary to obtain the desired depth of thread. ThewedgeV acts as a force transmission means which on `movement is instantaneously effective to positively initiate the gradual movement of the carriage die toward the ram die in increments of movement which may be controlled within almost infinitesimally small limits. The progressive forming action due to thegradual movement of the carriage die distributes the forming force over a long portion of the dies for increased die life and forms hardened stock.

On initiating operation, the operative faces of the carriage and ram dies are Vspaced apart a distance slightly less than the diameter of .the blank workpiece, but not close enough to form the desired depth of thread, which might subject the workpiece at once to pressures sufficient to distort it out of round. Fluid then is admitted to the cylinder 65 to move the wedge downwardly and the carriage die toward the 4rarn die as the blank workpiece is rolled along the face of the carriage die, forming the desired screw threads. Movement of the carriage die toward the ram die may be initiated when the workpiece 4is engaged between the dies.

The threads may be completed in one pass of the ram die :by rolling the blank workpiece once across the carriage die, in which case fluid will be admitted to the cylinder 65 to complete the full advance of the carriage die toward the ram die during the single pass of the ram die. Or, the threads may be formed by rolling the blank back and forth across the carriage die as, for example, back land forth one time and once again to the ejection end of the carriage die. In this case, fluid is admitted to the cylinder 65 to advance the carriage die toward the ram die partially during each thread rolling stroke of the ram die. Operation in the latter manner provides effectively longer dies, and permits the threads tobeformed on the workpiece more gradually for better finishing and more accurate sizing. Operation in this manner also avoids the ,necessity of subjecting the workpiece to the entire compressive forces necessary to form the threads Vin a single stroke, which tends to distort the workpiece out of round.

In order to control -the `depth of threads formedon the workpiece, movement of the connecting rod 69 is controlled by an adjustable stop means which limits move ment ofthe connecting-rod downwardly and thus limits movement of the carriage die toward the ram die. The adjustable stop means includes a threaded mid-portion 70 on the connecting rod 69 having a stop sleeve 72 adjustably threaded thereon. The stop sleeve is adapted to strike a stop surface 73 on the support 66 on downward movement of the rod 69.

T o permit adjustment of the stop sleeve 72 on the connecting rod 69, the sleeve is slidably keyed at 75 inside a cylindrical bearing 76. The bearing 76 is rotatably mounted at oppositeends in the base member 16 and the support member 66, and at one end is provided with a bevel gear 78. The gear 78 meshes with another bevel gear 79 on a shaft 80 mounted in bearings on the carriage 15 and terminating at the front of the machine in a squared end portion 81 adapted to receive a wrench or tool for adjustment. On rotation `of the shaft 80, the cylindrical bearing 76 is rotated through the gears 79 and 78, and since the stop sleeve 72 is keyed to the bearing 76, it is rotated also, threading the sleeve along the connecting rod. The shaft may be locked after adjustment by means (not shown) controlled by-a knob 82 (Figure l) at the front of the machine.

Theposition ofthe carriage 15 may be adjusted relative to the path of the ram die in order to accommodate workpieces of various diameters. To this end a threaded shaft 85 is rotatably mounted, 4and held against axial movement, in a depending portion 86 on the base member 16.

At one end, the shaft 85 is threaded into a frame ele- Ament 87 which forms la part of the bed supporting the ram die,and at the other Yend is provided with a pinion '88. The pinion 88 meshes with a pinion 59 on Aa shaft 90 (Figures 2 and 4) extending forwardly to the front of the-machine-and provided with-a'squared-end portion 91 (Figure l) adapted to receive a tool for adjustment.

Obviously, adjustment of the shaft 90 will effect rotation of the threaded shaft 85 to shift the carriage on the bed 12. The shaft 90 may be locked by means (not shown) controlled by a knob 92.

Referring now to Figure 6, the base structure for the machine includes a bed 100 reciprocably supporting the ram 101 which carries the ram die 5. The ram 101 is of a hollow frame construction having a generally H-shaped cross section closed at the top and bottom. Front and rear vertical members 102 and 103 are connected at their mid-portion and at the bottom by transversely extending members 104 and 105 welded or otherwise secured to the members 102 and 103. The frame is closed at the top by a cover member 106 welded to the members 102 and 103.

The member 102 constitutes a ram die supporting member and on its outer face is formed with a ram die receiving cavity similar to the cavity formed in the carriage die supporting member for the carriage die. The ram die is clamped at its ends on the member 102 between an end wall 107 and a clamping gib 37 (Figures 2 and 3). At the bottom and top, the ram die is clamped in place by frangible clamping members 39 and 40 (Figure 6) similar to those used in clamping the carriage die.

The ram is moved back and forth on the bed 100 by means of a hydraulic piston and cylinder device (Figures 1 and 2) including a cylinder 110 fastened to the supporting structure and a piston rod 111 connected to the ram. Fluid may be admitted to opposite ends of the cylinder 110 to move the ram and ram die back and forth past the carriage or compression die.

The machine is intended to be completely automatically controlled, though the entire uid and electrical circuits provided for this purpose are not shown. But to this end, it is desirable to automatically control the strokes of the ram die. For this purpose, the cover member 106 on the ram frame (Figure 6) is adapted to mount cams for actuating switches connected to solenoids which regulate valving controlling the admission of uid to the cylinder 110. Referring to Figures 2, 3 and 8, cam supporting members 115 are mounted on the cover 106 and the face of the member 106 is provided with a longitudinally extending T-s'ot 116 for receiving T-shaped nuts 117 on bolts 118 which releasably secure the members 115 to the cover 106. In this manner the cam supporting members 115 may be adjusted to any desired position longitudinally of the ram.

The cam supporting members 115 are provided with laterally spaced slots which receive elongated cam members C1, C2, C3, C4, and C5 retained in place by set screws 120 and adapted to actuate switches S1, S2, S3, S4, and S5, respectively. The switches S1 through S4 are utilized in controlling the rarn movements. The function of the switch S5 is described hereinafter.

As previously described, the threads may be formed in the workpiece by rolling it once across the carriage and ram dies or the blank may be rolled back and forth in three thread-forming strokes. If only a single pass of the ram die is desired, the switches S1 and S4 are utilized to reverse the ram at the end of its thread rolling and return strokes, respectively. The switches S2 and S3 are not utilized in this case. The cam C1 for actuating the switch S1 is adjusted to permit the ram die to Y move to an ejection position in which the workpiece will fall into the trough 10 after being rolled once across the carriage dies. The cam C4 for actuating the switch S4 is adjusted to permit the ram die to pick up a blank workpiece at the position W2 (Figure 3).

If it is desired to ro'l the workpiece back and forth across the carriage die, the switches S2 and S3 are also utilized and the former functions to interrupt the first forward stroke of the ram die and reverse the ram before it reaches a position in which the workpiece will be ejected. The switch S3 functions to interrupt the return stroke of the ram die and reverse the ram before it -6 reaches the original starting position. The switches-,S1 and S4 then function to control the next forward and return strokes of the ram as in the rst operation described.

The blank feeding mechanism 8 comprises a structure supported partly on the base structure which slidably mounts the ram 101 and supported partly on the side of the carriage 15 adjacent the starting end of the machine. It includes means dening a channel or trough extending angularly toward the leading edge of the ram die at the starting position and adapted to support and guide a blank workpiece W on end from a position W1 (Figure 3) where it is deposited by an operator to a position W2 between the leading edge of the ram die and the trailing edge of the carriage die where it is adapted to be picked up on movement of the ram die past the carriage die and rolled between the two dies. Means is provided to push the blank workpiece along the channel from the position W1 to the position 4W2 and an adjustable stop is provided on the rarn 101 to limit the movement of the blank to the desired position W2. One side of the channel is relatively stationary and the other side is formed of a spring biased member adapted to hold the blank in the position W2.

Referring now to Figures 3, 7 and 8 for a more detailed description of the feeding mechanism, the feeding and guiding channel is formed at the bottom by an elongated work supporting member which extends for the length of the channel and on which the bottom end of the blank workpiecevW is adapted to rest.

The structure for mounting the work supporting member 125 includes a base plate 127 secured by screws 128 to a frame member 129 forming a part of the base structure for supporting the ram. A vertically extending bracket 130 of irregular cross-section is secured to the base plate 127 by means of screws 131 which extend upwardly from the base plate into the bottom of the bracket 130 and by means of screws 132 which extend horizontally from an upstanding portion 134 of the base plate 127. The rear end of the work supporting memberl 125 is enlarged and formed with laterally extending dovetail projections 137 and 138 adapted to engage cooper ating vertically extending surfaces provided on the bracket 130. A vertically extending surface 139 on the bracket 130, which engages and guides the elongated portion of the member 125, functions as one side of the channel through which the workpiece is advanced. A retaining plate 140 is secured to the face of the bracket 130 by screws 141 and serves to retain the work supporting member 125 and to enclose a clamping gib 143 for clamping the work supporting member 125 iny adjusted vertical positions.

In order to adjust the vertical position of the work supporting member 125 to accommodate blank workpieces of different lengths, an adjusting screw is supported for rotation at its bottom end on the base plate 127 and at its top end by a bracket 146 secured by screws 147 to the bracket 130. Screw 145 is held against axial movement and engages threads formed on the work supporting member, and on rotation is adapted to adjust the vertical position of the member 125. A lock nut 148 is provided to retain the screw 145 in adjusted positions.

Referring to Figures 3, 4, 5 and 7, the feeding mechanism includes an elongated, reciprocably mounted pusher which may be actuated to push a blank workpiece along the work supporting member 125'from the position W1 to the position W2. The structure for supporting and actuating the pusher 160 includes a base` plate 162 secured to the side of the carriage 15 by means such as the screws indicated at 163. Integrally cast

brackets

164 and 165 extend horizontally from the base plate 162 and at their outer extremities, facing the ram 101, are joined by a vertically extending connection 163 having formed in its face a guide way 164 in which the pusher A1,60 is reciprocably supported. A cover plate 166 '-is secured by screws 167 to projecting portions 168 on the connection 163 and encloses the guide way 164' for the pusher 160.

In order to mount an actuating mechanism for the pusher, each of the

brackets

164 and 165 terminates in an integral vertically extending lip 170. The lip 170 on the upper bracket 164 extends upwardly from the plane of the bracket and is seen in Figures 3 and 4; the lip on .the lower bracket 165 extends downwardly therefrom and is seen in Figure 4. A mounting plate 171 is secured to the lips 170 by screws 172 and has secured thereto a piston and cylinder device connected to actuate the pusher 160. The piston and cylinder device includes a `cylinder 175, the periphery of which is seen in Figure 3 and the cross section of which is seen in Figure 5, secured in cantilever fashion to the mounting plate 171 by elongated bolts 176. A piston rod 178 extending from the cylinder 175 is connected by a bracket 180 to the end of the pusher 160. Fluid connections to opposite ends of the cylinder 175 are shown at 181 and 182. Obviously, uid may be admitted to opposite ends in the cylinder to move the pusher 160 back and forth in the work feeding channel.

In order to retard the movement of the workpiece W in the feeding channel and in order to hold the workpiece in the position W2, one side of the channel is formed by the pivoted work holding member 185, seen in plan view in Figure 3. As seen in the elevational view of Figure 4, the member 185 is formed with a relatively wide flat face extending for the height and the length ofthe feed channel andv having a bifurcated portion extending rearwardly of the channel and forming vertically spaced, upper and lower arms 186 above and below the level of the pusher 160. The forward end of Vthe connecting member `163', which supports the pusher 160, is provided with vertically spaced upper and lower `p ivot bosses 190 (Figs. 4 and 8) on which the projecting arms 186 of the work holding member 185 are pivotally mounted by means of pins 191 to pivotally support the work holding member 185 for movement about a vertical axis adjacent the rear of the channel.

The rearwardly extending arms 186 on the work holding member 185 are biased by spring means to force the forwardly extending portion of the member 185 against a workpiece held in the feed channel. To this end, a U-shaped spring mounting bracket 195 (Figs. 3 and 5) 'is secured to each of the horizontally extending

brackets

164 and 165, as by screws 196. The forward leg 197 of veach of the U-shaped brackets 195 is provided with a spring mounting pin 198 on which a spring 199 is supported to bear between the leg 197 and a recessed portion 200 in the rearwardly extending arm 186. In this `manner the forwardly extending portion of the work holding member 185 is biased toward the opposite side of the feeding channel to hold a blank workpiece W in the position W2 to which it is advanced by the pusher 160. An adjustable stop 201 limits movement of each of the arms 186 when no workpiece is in position in the channel.

In order that the workpiece will be properly posivtioned for pick-up by the ram die 5 when it is advanced past the carriage die 2, a stop device 205 is mounted on Vthe face of the ram 101 to limit movement of the blank to the face of the bracket.` The stop member 207 is thus substantially enclosed but projects at the trailing end fromithe housing `formed -by the bracket and cover plate and terminates in a stop element l210 which is engaged by a workpiece W to limit its movement by the pusher 160.

VThe stop member 207 is biased toward the ramvdic to an adjustable position by a spring 211 whichfis received in the hollow portion of the stop member.` The spring bears between an end closure 212 on the stop member and a tail plate 213 secured to the bracket 206. An elongated bolt 214 passes through the hollow portion of the stop member 207 and through the spring 211), and includes at one end a head 215 seated in an outer portion of the end closure 212. At the opposite end, the bolt 214 is adjustably threaded in the tail plate 213 and thus functions to limit the position to which the stop element 207 may be biased by spring 2-1-1. A lock nut 216 holds the bolt 214 in adjusted positions.

Referring to Figure 3, it should be clear that a blank workpiece W may be deposited in the position W1, where it rests on the work supporting member between the vertical surface 139 on the bracket 130 and the vertical face of the pivoted work holding member 185. At this time, as no workpiece is in the position W2, the forward end of the work holding member 185 is pivoted toward the vertical surface 139 to a position Vdetermined `by the engagement of the tail portions 186 with the adjustable stops 201. If fluid is admitted to the cylinder 175 now, to advance the pusher 160, the blank will be pushed on end along the feeding channel until it engages the s top element 210. The pusher 160 and the stop element 2 10 should be relatively adjusted so that the pusher 160 causes the blank to engage the stop element 210. fl'he strength of the spring 211 is such that the stop Aele.- ment 210 is not normally displaced by the pusher, the latter merely holding the blank in vposition until .it .is engaged between the dies. Movement of the workpiece along the feeding channel is retarded and the workpiece 4is additionally held in -the position W2 by the work holding member 185. In this manner, a `nice control is maintained over the blank workpiece to position and hold it exactly in the proper place for pick-up by the ram die on advancement past the carriage die. The workpiece may be supported in the feed channel by adjusting the member 125 to support the bottom end of the workpiece at the proper level, or the underface of the head of the workpiece may rest on the members and 185, as seen in Fig. 8.

In order that the blank workpiece will be properly positioned for pick-up on movement of the ram die past the carriage die, the stop element 210 should be adjusted so that the blank workpiece in the pick-up position W2 will have its center on a line extended from the leading edge 6 of the ram die 5 to the trailing edge 3 of the carriage die 2. In this manner, `the blank workpiece will be initially engaged by the two dies at diametrically opposite points and rolled by the ram die across the carriage die, immediately beginning the formation of the screw threads with equal effects produced on the blank by the two dies. The forward end of the work supporting member 125 is tapered at 125 so that the workpiece will overhang the member 125 to facilitate engagement of the work by the ram die. The workholding member 185 extends to a position adjacent the carriage die 2 and the surface 139 terminates short of the end of the member 185 to expose the workpiece adjacent the ram die so that it will be engaged on movement ofthe ram die. When the workpiece is engaged between the dies, the feeding movement of the carriage die toward the ram die may be initiated to compress the workpiece between the dies to complete the formation of the threads as the rolling is continued.

It should be noted that while the bracket 130 and the work supporting member 125 are supported onthe base structure of the machine, the pusher and the work holding member are supported on the carriage `15. Thus, on adjusting the carriage 15 to properly position the carriage die for workpieces of different diameters, the work feeding mechanism is also properly adjusted to accommodate the particular diameter of the workpiece.

In operation, it is desirable to automatically control the admission of uid to the cylinder 175 to actuate the pusher 160 and advance a blank workpiece to the position W2 at the proper time. To this end, the switch S5 is arranged to be actuated by the cam C5 adjacent the end of the return stroke of the ram die after a finished workpiece has been ejected. The switch S5 is connected to solenoids arranged to control valve means which regulate the admission of uid to the cylinder 175.

We claim: l

1. A thread rolling apparatus adapted to form threads on a substantially cylindrical workpiece by rolling the workpiece between cooperating dies comprising, in cornbination, a base structure, a carriage supported on the base structure, a slide having a compression die formed with a substantially at serrated face, means mounting the slide on the carriage for movement in a direction normal to said face of the compression die, a ram supported on the base structure and having a ram die formed with a substantially 'Hat serrated face arranged in spaced, parallel relationship to said face of the compression die, means mounting the ram for reciprocable movement past the face of the compression die between a starting position in which a blank workpiece may be inserted in pickup position between the dies and an ejection position in which a tinished workpiece is ejected from between the dies, means mounting the carriage for adjusting movement toward and away from the path of the ram die to vary the spacing of said dies to accommodate workpieces of different diameters, and means forming a feed channel extending longitudinally of the ram die and including opposed side members for supporting and guiding a blank workpiece into pickup position between the dies, one of the side members forming said channel being supported on said base structure and the other of the side members being attached to the carriage and movable therewith, the construction and arrangement being such that adjustment of the carriage to space said dies for workpieces of diierent diameters elfects a corresponding adjustment of the spacing of said opposed side members.

2. A thread rolling machine for forming threads on a substantially cylindrical workpiece by rolling it from a pickup position to an ejection position between relatively movable, straight, thread-forming dies, comprising, in combination, a pair of dies having opposed, vertically arranged, thread-forming faces, means mounting one of the dies for reciprocating movement horizontally from a workpiece pickup position to a workpiece ejection position wherein the finished workpiece is ejected from between the dies, and means for feeding the workpiece into the pickup position between said dies including means forming a horizontally disposed feed channel inclined relative to the path of said one die, extending angularly toward the pickup position and including opposed, parallel side members and a bottom member for supporting and guiding the workpiece for movement to the pickup position, one side member of said channel extending toward the pickup position and terminating at a position adjacent the trailing edge of said other die, the other side member of the channel extending toward the pickup position and terminating at a position adjacent the face of the reciprocable die and short of the terminus of said one side member thereby to expose the workpiece for pickup on movement of the reciprocable die past the other die, the bottom member of the channel extending beyond the terminus of said other side member of the channel and being tapered at the end adjacent the movable die the construction and arrangement being such that the workpiece will overhang the bottom member to facilitate pickup on movement of the reciprocal die past the other die. t

3. A mechanism for feeding substantially cylindrical workpieces on end comprising, in combination, a supporting structure, a feed channel carried on the supporting structure and including opposed side portions and a bottom portion for supporting and guiding the workpiece for movement on end from a position adjacent the entrance end of the channel to a position adjacent the exit end of the channel, means mounting one side portion of the channel stationarily on the supporting structure, means pivotally mounting the other side portion of the channel on the supporting structure adjacent the entrance end of the channel, means biasing the exit end of said pivoted side portion toward the stationary side portion, means mounting the bottom portion of the channel for vertical adjustment in the channel to accommodate workpieces of different lengths, and a pusher bar reciprocably mounted on the supporting structure for movement back and forth lalong the channel to push a workpiece from the entrance end to the exit end of the channel.

4. In a thread rolling apparatus, in combination, a pair of cooperating dies having flat thread forming faces arranged in spaced parallel relationship, means mounting one of said dies for reciprocal movement longitudinally of its operative face, a supporting structure adjacent the path of movement of said one die, a slide supporting the other of said dies and mounted on the supporting structure for reciprocal movement toward and away from the path of said one die; means for moving the slide toward the path of said one die comprising an inclined wedging surface formed on the slide, a wedge reciprocably mounted on said supporting structure and having an inclined sur- `face engaging the inclined surface on the slide, a piston and cylinder device mounted on the supporting structure,

t a connecting rod joined to the piston and to the wedge for moving the wedge; and adjustable stop means for limiting movement of the wedge in a direction which eifects movement of the slide toward the path of said one die including a stop member on the supporting structure, a stop sleeve threaded on the connecting rod and engageable with said stop member, and a second sleeve encasng the stop sleeve, journaled on the supporting structure for rotation relative to the connecting rod, and keyed to the stop sleeve for rotation therewith and sliding movement relative thereto so that rotation of the second sleeve is eective to adjust the stop sleeve axially of the connecting rod.

References Cited in the tile of this patent UNITED STATES PATENTS 959,455 Campbell May 31, 1910 1,045,022 Hauberg Nov. 19, 1912 1,460,061 Hamilton et al. June 26, 1923 1,734,752 Thomas Nov. 5, 1929 `1,749,086 Plumb Mar. 4, 1930 1,973,201 Fassinger Sept. 11, 1934 2,056,560 Boden Oct. 6, 1936 2,152,591 Hanneman Mar. 29, 1939 2,271,844 Olson Feb. 3, 1942 2,364,442 Hoern Dec. 5, 1944 2,367,398 Hoern Jan. 16, 1945 2,643,401 Lovsek June 30, 1953 2,643,404 Fray Iune 30, 1953 FOREIGN PATENTS 556,260 Germany Oct. 14, 1932-.