US1760567A - Die head - Google Patents

Description

- May 27, 1930.

I H, T. :sHEARE 111E HEAD Filed Sept. :50, 1935' s Sheets-Shet H. T. SHEARER DIE HEAD 8 Sheets-Sheet 2 Filed Sept. 30, 1925 m Tsharer' v M y 27, H. T. sHEARER 6 I DIE HEAD Filed Sept. 30, 925 a Sheets-Sheet 5 xiii L I j. r 45 I F 13. w

4 R m ai V 57- 6 .55 6/ 53 g4 g g5 v 45 gwuanto'a Harry ifs/18m:

May 27, 1930. H. T. SHEARER DIE HEAD Filed Sept. 30, 1925 8 Sheets-Sheet 4 t n a v n May 27, 1930. H. T. SHEARER DIE HEAD Fild Septso; 1925 v a sheets-sheet 5 DIE HEAD Filed pt. 50, 1925 8 Sheets-Sheet 6 Tshearer attozmq 2 7, 1930. H. T. SHEARER DIE HEAD Filed Sept. 30, 1925 8 Sheets-Sheet 7 144101 eater May 27, 1930. H. 'r. SHEARER DIE HEAD Filed p 1925 8 Sheets-Sheet 8 I gwuanioz Harry Tshearer Patented May 27, 1930 UNITED STATES P'ATENTOFFICE HARRY T. SHEAREB, OF WAYNESBORO, PENNSYLVANIA, ASSIGNOB- TO LANDIS MA.-

CHINE COMPANY, OF WAYNESBORO, PENNSYLVANIA, A. CORPORATION OF ZIPIIINIB'I'SYII- DIE HEAD Application filed September 30, 1925. Serial No. 59,563..

My said invention relates to a die head for machines such as are used for cutting threads on pipes, bolts, etc., and as here shown is embodied in a revolving thread-cutting die head using tangential cutters or chasers, said device usually acting on non-rotating work.

The primary object of my invention is to provide a die head of this character in two units divided approximately along a plane perpendicular to the axis of the head. Such a construction affords very important advantages over previously known devices. One advantage resides in the fact that it facilitates assembling and dissembling parts of the head which in ordinary constructions are operations of very considerable diificulfcy and which ordinarily are decidedly time- 'consuming.

Another object is to provide springmeans for opening the head which means does not act directly on the chaser holders and so does not affect the float of the chaser holders.

vReferring to the accompanying drawings, which are made a part hereof and on which similar reference characters indicate similar parts, I

Figure 1 is a side elevation of the device of my invention,

Figure-2, a front all the chaser holders removed save one, sai

elevation thereof with figure also serving as a face view of the front unit,

Figure 3, a rear elevation of the front unit,

Figure 4, a central longitudinal section of the front unit, on line 44 of Fig. 2,

Figure 5, a section on line 5-5 of Figure 2,

Figurefi, a section on line 6-6 ofFig- .ure 1, 4 a

Figure 7 a detail-of a part shown in Fig ure 6, looking in the direction of arrows 77 n Figure 8 is a central longitudinal section of the rear unit on line 8-8 of Figure 9,

Figure 9, a front view' of the rear-unit, Figure 10, a rear view of said unit, Figure 11, a longitudinal section of the assembled head, the "rear unit being secdicates the body member tioned on a plane corresponding to line 1111 of Figure 10,

Figure 12, a staggered longitudinal section of the assembled head showing a trunnion and its'attachments in section, and also a locking pin and adjacent parts,

Figures 13 and 14, detail longitudinal sections illustrating different positions assumed by the parts in opening and closing the head,

Figure 15, a detail cross section showing the locking pin in closed position,

Figure 16, a detail of a similar section showing the locking pin in open position when the head is provided with right-hand chaser holders, I

Figure 17, a similar section illustrating the open position when the head is provided with left-hand chaser holders,

Figure 18, a section of a head provided" Figure 21, a section on line 21-21 of Figv ure 20, I

Figure 22,'a section on line 2222 of Fig ure 20,

Figures 23 and 24, detail longitudinal sec;-

d tions of the head provided with tripping mechanism, said sections showing opening and fully open positions of the locking pins and related parts,

Figure 25 illustrates the method of assembling certain parts of the trip mechanism,

Figure 26 is a fragmentary plan view of certain parts shown in Figures 20, 24: and 25,

Figure 27 a section showing a chaser holder and a chaser,

Figure 28, a similar view of a modified form of chaser holder, 7

Figure 29, a side view of a modified chaser and chaser holder,

Figure 30, a face view of the same.'

In the drawings reference character 40 inof the front unit of the die head which together with the body member 41 of. the rear unit constitutes the head body of the die head, heretofore formed ina single piece. The two units are fastened together by screws 4C2 (Figs. 11 and 19). The head is supported on a shank 43 of an desirable or conventional form which shan has a flange 4- 4Wlth a reduced forward extension fittin inside the rear body member I 41 and r'ovi ing a centralizing feature for the hea The flange 44 is secured to the rear hflange 45 of the front body member 41 by means of screws 46. The bod member 40 as 1 usual is provided with bearings in which trunnions 47 are mounted, these trunnions carrying chaser holders 48. In the present embodiment of the invention the chaser holders are shown as provided with chasers 49 which are adjustable tangentially of the holders and are held inplace by means of clamps 50 through which pass screws 51. The chaser holders are mounted for oscillation with the trunnions .for opening and closing the head, i. e. for moving the chasers simultaneously toward and from the axis of rotation as for admission and removal of work. The chaser 49 has its base 110 and back 111 accuratel ground to seat against surfaces 106 and 10 on the holder, these surfaces determining the position of the chaser. Surfaces 108 and 109 of the -chaser may be left relatively inaccurate since a. clearance 118 is allowed between the face 109 of the'chaser and the face 1150f the 89 clamp 50'; The groove at the intersection of the surfaces 108 and 109 has a rounded bottom. vSurfaces 1'16 and 117 on the holder and 117 on the clamp may be left finished in a relatively inaccurate manner, since the clearance at 118 will allow the clamp to tilt slightly if necessary without affecting the position of the chaser. A groove 121 is provided in the chaser holder below the depending ridge of the clamp to permit dirt to escape lnstead of WOIkll'lg between the contacting surfaces of the clamp and holder.

Front unit The front unit comprises a front body member (Figs. 2, 3 and 4) having a rearward projection 52 (Fig. 4) on which a ring 1 53 is mounted said ring having a central aperture fitting about the projection and being secured to the front body member by temporary screws 54 and a dowel pin 55 (Fig. 3) adapted to fit in a hole in the ring and in any one of four holes 55' in the front body member 40. This projection 52 cooperates with a recess in the rear body member 41 to facilitate assembling of the parts and to prevent 'misalinement either in assembling or subsequentl thereto. The front body member is rovi ed at its forward end with a radial ange 56 integral with said front body member, said flange and the ring 53 providing spaced abutments between which are mounted afair of rings, the forward ring 58 being j usting ring for rotating the ring frame provided by rings 57, 58 and the rings of the rear unit, hereinafter described, about the er holder and trunnion will oscillate on the axis of the trunnion as the closing ring moves about the axis of the head.

Pins 61 (Fig. 12) extend through openings in the rings 53 and 58 and into openings in the ring 57 to move the ring 57 into headclosing position and to lock it in such position. The holes in the closing ring are provided with hardened bushings 62. to prevent enlargement of the openings therein by reason of wear which would finally cause inaccuracy in the position of the chasers and difiiculty in closing the head, said bushings being readily renewable in case they become worn.

The adjusting ring 58 is secured to the head body by .means of teeth 63 forming a worm gear engaging with a worm formed on a bolt 64 (Figs. 2 and 6). The bolt is provided at its upper end with a head 65 having a tapered portion 66 calibrated to cooperate with a zero mark at 66 on an adjacent portion of the ring 58 for indicating the adjustment'of the ring frame relatively to the head body and'consequently the size of the opening between the chasers when the head is closed. At its lower end the bolt has a washer 67 with a squared opening receiving the squared portion of the'bolt. A nut 68 threaded on the bolt serves to force the washer along the squared portion of the bolt so as to bring the adjacent faces of the washer and the head 65 into frictional relation to corresponding faces on the ring and so make a neat turning fit. Thisarrangement does away with any special locking arrangem'entfor the worm as the worm is under friction at all times when in use and will not move from its correct setting. When looseness occurs due to wear the washer is forced further along the bolt by turning the nut, so as to maintain such fit without backlash, the nut locking itself against the washer. In certain previous constructions where similar worm gearing was used the screw had to be clamped down into locking engagement with the bottom of its bore or socket by means of a locking screw and when the workman after adjusting the head locked it down by said clamping screw the worm would sometimes turn and thus,

spoil the adjustment. The present arrangement makes adjustment of the head very easy.

The ring 53 is stationary with the body member being fixed thereto by screws 54 and pin 55 and is provided with clearance slots at 69 for the pins 61. The amount of adjustment by the worm and worm teeth is indicated by means of calibrations on the ring 84 and one or more zero marks on the ring 53 which may also be referred to as a zero inserted in another one of the openings 55' or may be cut OE and a new one used in place of the old one. Such manipulation leaves the calibrations on ring 84 at a. distance of 90 degrees more. or lessfrom the corresponding zero marks and it is now necessary to tunn the ring frame through a corresponding are about the head body to bring the zero marks and calibrations into proper relation. The.

adjustment described can be made by any one using a die head and obviates the necessity for expensive and time-consuming regraduating of the die head.

The trunnions 47 are held in place on the front unit by means of threaded rearward extensions projecting through the ring 53. Nuts 76 are threaded on said extensions and having enlarged forward faces bearing against the ring 53, the forward ends of the nuts being approximately ,of the same diameter as the trunnions. Screw plugs 77 are threaded into the nuts 76 and are provided at their forward ends with tapered portions engaging tapered openings in the rearward extensions of the trunnions thereby locking the nuts 76 in place against accidental loosening. It will be seen that the screw plugs and the nuts are in line with the bores in the body member of the rear unit and therefore can be adjusted or removed without dissembling the head. It will be evident that this construction makes for easy adjustment to secure absolute uniformity in the float or endwise movement of the various trunnions. It provides also for absolute parallelism in the various faces which extend transversely of the axis of the front body member and ring 53. A spring 78 for moving the closing ring in a direction to swing the chaser-holders outward and so open the head is arranged approximately tangentially of the head body in a bore having two alined portions approximately tangential to the head body and an intermediate enlarged portion. A-n abutment in the form of a pin 79 fixed in the ring 58 extends into said enlarged portion and said pin is flattened at opposite sides for engagement-with one end of spring 78. A hollow screw-plug 80 is threaded into one of the alined parts of the bore, the spring 78 resting in the hollow portion of said plug. A second screw-plug 81 closes the other one of said alined portions. When left-hand cutting is to be done, the right-hand chaser-holders are removed and left-hand chaserholders are substituted, the plugs 80 and 81 being exchanged and the spring 78 moved to the other side of abutment 79. The tapered ends of the pins 61 do not become disengaged from the bushings 62 when the head is opened,

as hereinafter explained, and the rings 84,

85 and 86 may therefore be forced forward toward head-closing position by any conventional or desirable means, rotating the closing ring 57 against the force of the spring 78 and compressing the spring. Ashere shown the chaser holders are separate from their trunnions and are secured thereto by screws 82 each having a head extending into a counterbore in the chaser-holder,. the trunnions also having a part extending into such a counterbore. An inclined pin 83 extends through a small opening in the chaser holder and into the trunnion, said pin serving as a preliminary alining means'for positioning the trunnion relatively to the chaser holder and holding the parts in place while the screw 82 is being tightened. The inclination prevents damage to the trunnion by the bulging or cracking-of the metal between the pin and the adjacent periphery of the trunnion.

Rear unit tion of the ring 84, while thering 85 is secured to ring 84 by screws 87 (Figs. 10 and 11). The three rings are mounted for sliding movement lengthwise of the rear body member 41, their forward movement being limited by the ring 53 and their rearward movement bythe flange 45. This movement of the rings is caused by a yoke having-pins Ill engaging in sockets 88 in the ring 86, saidyoke being of conventional form. It will be evident from Figs. 12, and 13 to 17, which show the parts in closed position,at opening point, and in fully open position that the pins 61, which are attached to the rear unit by means of reduced rear ends 89 held in the ring 84, are never wholly out of engagement with the closing ring. The tapered ends of the pins rest against the tapered faces-75 (Figs. 4 and 8) on the bushings 62 when the head is fully open and the engagement between the tapered faces on the pins and the tapered faces on the bushings facilitates the rear body member 41 and in the rear flange for stopping rearward movement of the rings 84, 85 and 86 on the head body.

Operation It is thought that the process of assembling the head so far described will be understood upon consideration of the drawings and especially Figures 4 and 8. The temporary screws 54 are left in place until the front and rear units are to be united, when they are taken out, screws 42 fitting in the same tapped holes that held screws 54. If preferred, four additional holes may be formed in the head body and four corresponding clearance holes in ring 53 in position to receive screws 42, when screws 54 may be left permanently in place as in Figure 3.

Heads such as shown in this case cooperate usually with non-rotary work, the work moving lengthwise of the machine and apart moving with the work striking the yoke (or a part attached thereto) to move the yoke in one direction. The movement of the yoke moves the rings 84, 85 and 86 and withdraws the pins 61 from engagement with the closing ring .57 until such point is reached as is shown in Fig. 13. When this point is reached the head is opened partly by reason of the pressure of the work against the chasers which pressure tends to separate the chasers and open the head and partly by the action of springs such as that shown at 78.

Figures 13 to 17 illustrate the different positions of the pins 61 relatively to the closing ring. In Figure 13 the pins have been withdrawn from the locking position by a movement of the rings 84, 85 and 86 through the medium of the yoke engaging the sockets 88 to.,apoint where the spring 7 8 can come into action by reason of the engagement between the beveled surfaces at the ends of the pins with the inclined surfaces 75 on the bushings 62. At this time the reaction due to the en gagement of the chasers with the work tends to force the head 0 on and this is reenforced by the expansion 0 the spring 7 8 so that the head will open. Figure 14 shows a later position with the rings against the flange and the head open. Fi ure 15 is in efi'ect an end view of the pin in t e position of Figure 13 and Figure 16 an end view in the fully open position. It will be understood that by substituting left-hand chaser holders for the right-hand chaser-holders illustrated the head may be operated to cut to the left-hand instead of to the right-hand and in such case open position will be as at Figure 17.

In the operation of the die head the yoke, not shown, will be actuated to move the rings 84, 85'ai1d 86 and the pins 61 forward from the position of Figures 14 and, 16 into the pochasers against the work and the pressure of" the spring 7 8 acting on the inclined surfaces of the pins and the bushing 62 will move the yoke, the rings 84, 85, 86 and the pins 61 back to the position of Figs. 14 and 16 in which position the opening of the head is limited by the continuing engagement of the points of the pins with the bushing 62 and the abutment of ring 85 against flange 45.

Internal? trip mechanism I have shown a trip mechanism in connection with amodified form of my invention (Figs. 18 to 26), this trip mechanism comprising a head 93 having means for reaming the end of a pipe internally and chamfering it externally, such head being connected by screw threads to a rod 94 with a handwheel 95 for turning it to release the head. A hollow shaft 96 is mounted concentrically with the rod 94, said hollow shaft having a hand wheel 97. The rear end or neck of the head 93 is-squared, as indicated in Fig. 21, and fits in a square opening in a sleeve 98. The sleeve 98 in turn has a squared rear end of reduced diameter fitting in a squared opening in the reduced forward end of a s ider 99 which squared opening is threaded or a part of its length to engage with a threaded portion of the hollow shaft 96. It will be evident that the turning movement of hollow shaft 96 adjusts sleeve 98 which in turn positions head thus providing for convenient assembling of the parts of the spider.

In assembling the device-of Figures 18 to 26 the front unit, which is identical with that of the form first described, maybe taken out of stock. A rear unit is then brought into 0 erative relation with the front unit as in t e assembling operation of Figure. 8, the rear unit being substantially similar to that shown in Fi ure 8 save that a part of it'has been remove to provide a space as indicated at 103 in Figure 19-, this space being for the accommodation of thespider 99. These parts are secured together by screws 42 as illus-' trated in Figures 11 and 19. The spider is 3o inside and outside.

rings 84', 85 and 86 with pins 61 move to now positioned in the head as shown fn Figures 19 and 20 and thereafter the rod 94 and the hollow shaft 96 are positioned in the.

spider. Pins 104 are now inserted through the alined openings 102, 101 and 100 into openings in the' spider in the manner illustrated in Figure 25 where they may be secated in Figure 19, to permit adjustment of the rings about the head body for cutting work of various sizes.

Operation of internal trip In the operation of my device when pro 20 adjustment of shaft 96 after which the rod 94 is tightened to lock the head of'the tripping mechanism in adjusted position. There upon the head may be set in motion which is usually rotary while the work is non-rotary 5 and travels along thebed of the machine.

The operation continues until the head 93 of the trlpping device engages the work, which in this case is'supposed to be a section of pipe, whereupon it first shapes theend of the pipe When the pipe strikes the. connecting surface between the surfaces that shape the inside and outside of the pipe a rearward movement of parts 93 to 99 inclusivetakes place and through the medium of pins 104 the rings 84'", 85 and 86 are pushed rearward until the parts reach the position illustrated in Fig. 23 where the plns 61 engage at their tapered ends with the beveled faces on bushings 62. When this position is reached the reaction of the chasers pressing against the work in combination with the pressure of the spring 78 turns the closing ring 57 and thus causes the chaser holders to move pivotally in a manner to withdraw the chasers from the work. The

a position as shown in Fig. 24. The openings at 101 are elongated axially to permit the rings 84, 85' and 86 and the pins 61 to move as above described independently of the spider 99 which is moved only by the endwise push of the work. The heads 104 of pins 104 are flatt'enedso as to permit a greater movement to the rings, and are extended laterally to limit the inward movement of the pins. The headmay be closed after withdrawal of the finished work, by acting on the yoke (not shown) which moves rings 84', 85, 86','5'Z and pins 61 to positions for closing and locking the head.

The modification in Fig. 28 shows a chaser and clamp formed in the same way as those in Fig. 27, the chaser-holder, however, having the trunnion 91.integral therewith. A

screw at 122 serves to adjust the chaser in the direction of its length as usual.

The chaser holder 48 shown in Figures 29 and 30 is or may be the same as in Figure 2. The clamp 50 is secured to the chaser holder by screws 51 and preferably extends further down along the chaser 49 than does clamp 50 in Figure 27, the faces 123 and 124 being respectively inclined at 45 degrees and 15 degrees. The clamp is otherwise similar to that of Figure 27 In further explanation it may be stated that the position of the nuts 76 makes it very easy to adjust the trunnions when the front and rear units are separated, as well as to assemble the front unit or take it apart. In previous constructions the nuts or adjusting screws for holding the trunnions and determining their float were inside the bores of the'head body; i. e., forward of the rear face of said body and hard to get at. Even when flush with said face they were more difficult to ,manipulate than in the present device.

The use of a single axial locking screw on the trunnion does away with any tendency to tilt the adjusting nut in locking the ad justing screw in place. In some previous constructions, where three or more locking screws were used unequal tightening of the adjusting screws tended to cause misalinement of the adjusting screws. By inserting a screwdriver through a socket wrench the adjusting nut and its locking screw can readily be manipulated.

Bymeans of the new construction I avoid the use of a separate front holding ring on 1 the head body. It is a matter of great diificulty to machine the front and rear faces of a separate ring such as that shown at 30 in the patent to Miller 1,296,546 so accurately that the rear face will lie closely against the faces inthe annular depressions on ring 15 and head body A (which surfaces must also be machined accurately) while the front face of the ring lies in-the plane of the front faces of ring 15 and head body A. In practice the expense of such exact machining is prohibitive, and the recess in the head body is cut deeper than necessary, after which annular shims are used to fill the space between the holding ring and thehead body, when it.

frequently happens that the holding ring is caused to project forward too far.

The inner and outer peripheral surfaces of the holding ring should also be machined accurately so as not to leave cracks in which dirt may accumulate whereby also the smoothness of the front face of the head may be impaired as by reason of metal chips catching in such cracks. Such chips also often catch in the slots of the exposed screwheads and interfere with the opening and closing of the head. The holding ring has depressed seats for the screws which seats often break down more or less and render the holding action uncertain. Also the screwheads often become bent and interfere with the head-opening and closin movements.

-These dilficulties are avoided 1n my present device where the front holding ring is integral with the head body and the shims, if any,'are positioned between the head body and the rear ring of the front unit of the head body and can be of substantial width instead of being ofno greater width than the holding ring of the prior construction, thus being made more permanent and-more effective. The prior construction in which the rear holding ring of the head body is integral and the front holding ring is removable made the die head very difficult to take apart, it being practically impossible to pry the ring out or otherwise remove it from its seat with tools. With the present construction the units can readily be separated and the rear ring of the front unit can readily be removed from the front head body member. The bolt 64 is now removed and then the entire front unit comes apart. I

The two unit head is a matter of convenience also in the factory in that the front unit can be used without alteration with either a plain rear unit or with a rear unit including a trip mechanism as shown in Figures 18 to 26. This makes it possible to fill orders for either plain heads or heads with tri s with a smaller number of actual parts he (1 in the stockroom.

Another feature of advantage in the present construction resides in the fact that the bores for the trunnionspass straight through the head body. In prior constructions they commonly are counter bored either from one or both ends of the head body and the bores must be finished from one or both ends, this necessitating a much greater number of operations than in the present construction and giving a less accurate result as compared with the present construction where. all the finishing is either on the walls of the straight bores or on the flat outer contacting faces at the rear of the head body and at the front of the rear holding ring 53.

By my present construction the scale on the periphery of the head is in plain view while the bolt 64 is being operated to adjust the head, as is also the scale at 66, which conduces to quick adjustment.

'WhiIe as a matter ofconvenience I have shown and described only that type of machine in which the die'head rotates to operate on V non-rotatin eration it is to be understood that I do not confine myself to devices of that type as the work may rotate and the head may advance on ways toward the work, etc. In cases where the head advances towardthe-work,

'the abutment for tripping the yoke on the work which moves. toward the die head uring the cutting ophead is stationary, as usual. It will be obvious, also to those skilled in. the art that various changes may be made in my device without departing from the spirit of the invention, and therefore I do not limit myself to what is shown in the drawing and described in the specification but only as indicated in the appended claims.

Having thus fully described my said invention, .what I claim as new and desire to secure by Letters Patent, is:

1. In a die head, a front unit comprising a head body member having an integral annular fiange at its forward end, chaser-holders, a closing ring surrounding the body member, a ring adjustably-secured to the body for varying the size of the opening between the chasers, a rear unit comprising a rear body member, a ring about said member, a pin carried by said ring said pin fitting in a hole in the adjusting ring and adapted to engage the closin ring to lock the head closed, a zero plate xed to the front body member between the rings on the respective units and calibrations on a ring ad acent said plate coacting with zero marks on the plate for indicating the size of said opening between the chasers, substantially as set forth.

2. In a die head, a front unit comprising a body member having parallel bores therethrough, trunnions mounted in the bores, chaser. holders mounted on the trunnions, tangential chasers in the holders, a closing ring mounted on said body and connected to said chaser holders, an adjusting ring mounted on said body, means for adjusting said rings around said body to vary the cutting size of said die head, a flange on the front of said body member, and a plate secured to the rear of said member by which the rings are held against axial movement relative to the said body, the said plate being connected to and positioning said trunnions against axial movement in said bod a separate rear unit comprising a head bo y member, a plurality of rings surrounding said head body member, locking means mounted in said rings on the rear unit head body member engaging the rings on the front unit head body member for locking the die head in closed position and unlocking the die head for open position, and means for securing the head body members together, substantially as set forth.

3. In a die head, a front unit comprising a body member having parallel bores therethrough, trunnions mounted in. the bores, chaser holders mounted on the trunnions, tangential chasers in the holders, a closing rin mounted on said body and connected to sai chaser holders, and adjustin mounted on saidbody, means for ad usting said rings around said body to vary the cutting size of said die head, a flange on the front of said body-member, and a plate secured to Ill ring

the rear of said member by which the rings are held against axial movement relative to. the said body, the said plate being connected to and positioning said trunnions against axial movement in said body, a rear unit comprising a head body member, a series of rings surrounding said head body member, pins mounted in one of said series of rings, means for laterally moving said series of rings whereby said pins lock said closing ring of the front unit in locked position, substantially as set forth. 4. A die head comprising assembled front and rear units, tangential chasers mounted on the front unit, a plurality of rings mount ed on the front unit, a spring mounted between two of said plurality of rings for opening the head, said plurality of rings being adjustable circumferentially about a body member for varying cutting size of die head,

' d gaid spring maintaining uniform tension reardless of adjustment to vary cutting size, said rear unit comprisin a plurality of rings mounted on a body mem er, said plurality of rings carrying locking means comprising conical pins extending into the plurality of rings of the front unit for locking the die head and said plurality of rings on the rear unit moving axially of the bodymember for unlocking the head, said conical pins acting against the tension of said spring during closing action of the die head, substantially as set forth. V In witness whereof, I have hereunto set my hand. at Waynesboro, Pennsylvania, this 5 twenty-sixth day of September, A. D. nineteen hundred :and twenty-five.

HARRY T. SHEARER.

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