US1617403A

US1617403A - Automatic compensating chuck

Info

Publication number: US1617403A
Application number: US696381A
Authority: US
Inventors: John E Lovely
Original assignee: Jones and Lamson Machine Co
Current assignee: Jones and Lamson Machine Co
Priority date: 1924-03-01
Filing date: 1924-03-01
Publication date: 1927-02-15
Anticipated expiration: 1944-02-15

Description

Feb. 15, 1927. 17,403

J. E. LOVELY AUTOMATI C COMPENSATING CHUCK Filed March 1 1924 7 Sheets-Sheet 1 IZ ZZUQ/ZYW (757272 Ji'fiaver J. E. LOVELY AUTOMATIC COMPENSATING CHUCK Feb. 15, 1927.

Filed March 1924 7 Sheets-Sheet 2 Feb. 15 l 927 J. E. LOVELY AUTOMATIC COMPENSATING cnucx 7 Sheets-Sheet 5 1560a '71' (70%;? Z law? Feb. 15, 1927.

J. E. LOVELY AUTOMATIC COMPENSATING CHUCK Sheets-Sheet 4 Mew & Jku Z. liafleg m q m Filed March 1 1 617,403 Feb. 15, 1927. J E LOVELY v AUTOMATIC COMPENSATING CHUCK Filed March 1924 '7 Sit et-Shee'lf. 5

as M

Feb. 15 192 7 J. E. LOVELY AUTOMATIC COMPENSATING CHUCK 1924 7 Sheets-Sheet 6 Filed March 1,

Feb. 15, 1927. 1,617,403

J. E. LOVELY AUTOMATIC COMPENSATING CHUCK Filed March 1924 Sheets -Sheet '7 L757? Illa Patented Feb. 15, 1927.

arena ear in ear JOHN E. LOVELY, F SPRINGFIELD, VERMONT, ASSIGNOB TO JONES 80 LAWSON MA- CHINE COMPANY, OF SPRINGFIELD, VEBIVION'L, A CORPORATION OF VERMONT.

AUTOMATIC COMPENSATING CHUCK.

Application filed March 1, 1924. Serial No. 696,381.

This invention relates to chucks designed for supporting irregular forms, more particularly crank and cam shafts and the like, correctly centered with relation to their bearings so that these bearings may be turned and faced. Chucks as heretofore designed for this purpose have commonly been provided with set screws arranged to bear on the work at spaced points and ithas been necessary to carefully bring up each screw individually to properly center thework and then to tighten them individually, turning the work over by hand so that each screw in turn may be rendered accessible for both bringing up and tightening. Considerable time is thus required to set up the work before machining can be commenced.

According to the present invention a floating clamp automatically adapting itself to the configuration of the work is employed, this clamp after it has properly engaged the work being fixed by a single fastener against further floating relative to the axis of rotation of the chuck. Thus but two clamping actions, each of a very simple and easily effected nature, are necessary to properly'secure the work for the machining operations.

Work such as gas engine cam shafts and long slender pieces it has heretofore been necessary to turn or spot intermediate its ends and then to use a steady rest bearing on the spotted portion.

The present invention eliminates the necesthe steady rest.

For a more complete understanding of this invention reference may he had to the ac companying drawings in which- Figure 1 is a fragmentary elevation of a lathe of the well known Fay type showing a compensating chuck particularly designed to support engine crank shafts in order to turn their bearings.

Figure 2 is an elevation of the crank shaft. Figure 3 is a perspective of a portion of the lathe looking down on the work toward the headstock end.

Figures 4 and 5 are perspectives of the work clamping jaws. I

Figure 6 is a section on line 6-6 of Figure 1.

Figure 7 is a fragmentary rear elevation of the parts shown in Figure 6.

sity of the spotting operation and the use of

F gures

8, 9, 10 and 11 are detail sections on

llnes

88, 99, 10l0 and 11-11, respectively, of Figure 6, Figurefi also represent ng a section on line 88 of Figure 11.

F gure 12 is a perspective of a gage block.

Figures 13 and 14 are elevations of this block looking from opposite sides.

Figure 15 is a detail plan showing the gage block in position relative to the work and to theface of the chuck.

Figure 16 is a section somewhat similar to Figure 11 but shown in connection with a modified form of chuck particularly designed for holding gas engine cam shafts. The cam shaft is also shown in relation to certain of the machining tools.

Figures 17 and 18 are perspectives of the clamping jaws for the chuck illustrated in Figure 16. Y

Figure 19 is a section on line 1919 of Figure 16.

Figure 20 is a section on line 2020 of Figure 19.

Figure 21 is an elevation of the support for the clamping jaws.

Figure 22 is a section similar to Figure 19 but showing a modification.

Figures 23 and 24 are sections on lines 23-9. and 24-2-1 of Figure 22.

Figures 25 and 26 are plans of the clamping jaws of Figure 22 looking in opposite directions.

. Figure 27 is a View similar to Figure 21 but showing the modification of Figure 22.

Figure 28 is a perspective showing a further modification of one of the clamping aws.

Referring first to Figure 11 at 1 is indicated a support or drum adapted to be fixed at one end 2 to the end of the machine spindle 3. As shown the drum has a central externally threaded hub or boss 3 thereon having a slot 4 therein for the reception of a. key 5 fixed to the end of the spindle 3, the spindle terminating in an annular shoulder 6 against which may engage the inwardly turned flange 7 of a collar 8 havinc: internal threads 9 engaging the threads of the boss or hub 53 by which means the drum may be clamped to the end of the spindle to rotate therewith. Within the spindle is carried a machine center 10 which is shown as mounted with capability of axial movement, being pressed outwardly from the-end of the spindle as far as permitted by the end of a screw plug 11 'riding in a slot 12 therein by means of a spring 13 seated in a socket 14 axially of the spindle and reacting against the end of a pin 15 having a head 16 threaded in a sleeve 17.- The sleeve 17' also slidably receives the center 10 at its outer end and at its inner end it has fixed therein the forward end of a rod 18. This rod 18 forms part of the standard centering mechanism of a Fay lathe. The sleeve 17 has enlarged forward portions 20 fitted within a bore 21 in the end wall of the support or drum 1, and mounted in a longitudinal perforation 22 therein is a rod 23 engaged at its outer end by a threaded adjusting plug 24. The inner end of the rod 23 bears against the outer end of an externally tapered sleeve 25 riding in the internally tapered bore 26 of the spindle 3. This sleeve 25 at its outer-end passes within the bore through the end of the drum 1 and serves to center it accurately with relation to the axis of rotation of the spindle.

The drum 1 is hollow and may receive work through an opening 30 in its opposite end. the work being herein shown as a crank shaft 310, one end of which may bearagainst the center 10. This outer end of the drum or support is designed to carry work-clamping mechanism which may adapt itself to the configuration of the work to be held and then be clamped to the drum to rotate therewith. This mechanism is so designed that it may engage the rough forging directly without requiring any preliminary spotting or turning. It comprises a clamping member or jaw 31 shown detached in Figure 5 and a mating clamping jaw 32 shown detached in Figure 4. The jaw 31 at one end has a pair of spaced ears 33 between which is pivoted a lug 34 projecting from the member 32 there being mating perforations and 36 in these parts through which passes a pivot pin 37 (see Figures 6, 7 and 9). This pivot may be fixed in position by means of a plug 38 threaded in a perforation 39 in the lug 34, the inner end of this plug engaging a depression in the pin 37. A lock plug 40 may be threaded in the socket 39 and bear against the outer end of the plug 38.

The work-clamping member 31 has a transverse keyway in its rear face and slidable in this keyway is a key 46. This key is provided with a perforation through which extends with a close fit a pivot bolt 48. This bolt also extends with a close fit through a perforation 49 in the end wall of the drum and with a loose fit through a perforation 50 through the member 31. This perforation 50 is counterbored at its outer end at 51 to loosely receive the head 52 of the bolt 48 and the opposite end of this bolt has threaded thereon a pair of nuts 53 by which it may be fixed in position. \Vith this construction the member 31 may be moved along with the key 46 across the endv face of the drum and it may also pivot about the in 48. It is not, however, permitted any odily movement laterally of the length of the. key. In the position of the chuck when it is stationary for the insertion or removal of work, this key 46 extends substantially horizontally so that the member 31 is permitted a roking movement and a bodily horizontal movement, but no bodily vertical movement, this construction furnishing a floating connection between the member 31 and the drum. As the jaw 32 is carried by the member 31, it also is capable of a floating movement relative to the end face of the drum with the member 31.

Means are provided for clamping the jaw 32 to the member 31 to fix the work rigidly therebetween. This may comprise, as shown best in Figures 3 and 6, a bolt pivoted at 61 between jaws 62 of the member 31 and having threaded on its outer end a nut 63 engageable with the upper faces of a pair of jaws 64 between which the bolt 60 may be moved. One or both of these

clampingn'iembers

31 and 32 may be provided with removable wear pieces 65 engaging the work.

Due to the floating movement of this clamping mechanism comprising the clamping jaws, this mechanism may conform to the position of the work placed between the center 10 and a dead center ofthe machine so that the work may find its own center relating to the chuck. If then this mechanism is clamped in this position to the drum it will therefore be properly held in this centered relation for the machining operations. Means for holding this mechanism in. position may consist of a clamping rod slidable axially with a tight fit through the drum 1 and havin a head 71 at its outer h end which may be brought against the outer face of the clamping mechanism and hold it tightly against the end of the drum.

As shown in Figures 8 and 11 the drum is provided with a perforated boss 7 2 within which is slidablv keyed a bushing 73. Slidable through this bushing. but keyed against relative rotation thereto, is the rod 70. Beyond the inner end of the boss 72 a collar 74 is fixed by means of a set screw 7 5 to the bushing 73 to fix its limit of movement toward the outer face of the drum 1. Bearing against the inner end of the bushing 72 is a thrust ball bearing 76 of any suitable type and against the rear face of this thrust bearing is positioned a collar 77 threaded on the rod 70. This collar has fixed thereto a handle 78 by which it may be turned. the

parts being so related that by pulling thehandle 78 forwardly the collar 77 is turned in a direction to move the rod 70 axially to bring the head 71 thereof toward the outer face of the drum. These parts are within the circumferential outline of the drum so as not to project thei'ebeyond as the chuck is rotated, and the side wall of the drum is discontinuous to form a large opening 19 through which access may be had to actuate the handle 78. On the opposite side of the collar 77 the rod is of reduced diameter and surrounding this reduced portion is a spring 79 bearing at one end on acollar 80 and at the other end against the inner wall 2 of the drum 1. This reduced extremity of the bar 70 passes through a perforation in this wall and is threaded at its end to receive abutment nuts 82 which limit the possible movement of this rod in a dire tion to move the head 71 away from the opposite end face of the drum, such movement being urged by the spring 79. The rod 70 passes loosely through a perforation 83 in the member 31 and its head rides in a counterbored portion 84 thereof, the parts being so proportioned that the head 72 may bear against the base of the counterbored portion but permit the desired floating movement of the member 31 relative to the drum before the head 71 is brought up tightly tliereagainst. As the clamping mechanism has its floating and pivotal connection to the drum eccentrically thereof, means is provided for counterbalancing the eccentric weight thereof when the chuck is in its stationary loading and unloading position so that this weight may have no effect in determining the clamped position of the work. For this purpose the member 31 may have a vert cal perforation 85 therein in the lower portion of which is axially slidable a pin 86 which may rest against an abutment screw 87 threaded in the end of the drum 1 as more clearly shown in Figure 10. The clamping jaws are held up b a spring 870 positioned above the pin 86, t e lower end of the plug 88 threaded in the upper end of the perforation 85 bearing on the upper end of this spring.

Means is also provided for supporting the outer end of the drum for rotation, this being in the nature -of a steady rest. As shown best in Figure 11, near the outer end of the drum 1 is a rib 90 having its periphery finished to form a journal portion hearing within a ring 91. The ring 91 is split as at 92 (see Figure (3) and the two ends may be sprung apart by means of a pin 93 threaded in an opening in one end of the ring and having a reduced extremity 941 bearing in a socket in the other. The position of the pin 93 may be fixed by means of a locking pin 95 also threaded in the socket and bearing on the head of the pin 93, the pin 95 being held in position by means of a set screw 90. The ring 91 is fastened to a supporting frame member 98 by means of bolts 99 passing through enlarged openings 100 in the frame member and threaded in the ring 91. These enlarged openings permit adjustment of the ring 91 relative to the frame member and this adjustment may be effected at spated points about the circumference of the ring in order to cause the ring to be accurately adjusted to bear on the bearing rib 90 of the drum throughout its circumference. This isaccomplished by means of a series of threaded plugs 101 seated in radially arranged openings spaced about the periphery of the frame member 98 and bearing at their inner ends on the outer circumference of the ring 91'. These plugs may be fixed in adjusted position by means of set screws 102 passing through the frame member 98 at right angles to these plugs and bearing at their inner ends thereon. Other adjusting plugs 107 bear on shoulders 108 adjacent to opposite ends of the split ring 91. i

As shown best in Figures 6 and 7 the frame member 98 is fixed to the body of the machine by clamp plates 103 held in position by bolts 104 and may also be clamped by means of clamping bolts 105 about one of the tool-carrying bars 106 forming a part of the Fay lathe.-

\Vhen a crank shaft is to be machined the shaft should be adjusted lengthwise in order that the tools which are used to machine the center bearing shall be correctly related ax- This gage block 110 has a pair of oppositely all of these faces being in a common plane and being adapted to be brought up against the outer face of the clamping mechanism. The crank shaft is placed in position, the tailstock spindle T of Figure 11 being retracted and the spindle 10 being projectedby the spring 15 to its outer limit of motion.

In this position of the parts the throws A and B of the crank are outward of the clamping mechanism. The tailstock is movedup to engage the outer end of the shaft and the gage block is then placed-in position between the crank throws as illus trated in Figure 15. moved toward the headstock, the center 10 retracting until the faces 114, and 116 The tailstock is then g bear against the clamping mechanism. The"

tool carriages

120 and 121 are so positioned relative to the clamping mechanism that they will take off equal portions of the checks of the crank throws in this position of the parts. \Vhen the clamp has thus been adjusted to the proper axial position the gage block is removed, a handle portion 118 being provided thereon so that it may be readily handled. The clamping awsare then engaged about the shaft, the rod 70 being in its released position to permit the clamping mechanism to float so that this mechanism may accommodate itself to the natural position of the shaft. These clamping elements are then brought into clamping relation as above described, and then by pulling over the handle 78 they are frictionally clamped against the outer end face of the drum to rotate therewith. By th1s procedure the shaft is properly centered and arranged lengthwise properly so that the machining operation performed on the center bearing is accurately related to the axis and length of the shaft. A crank shaft of this description is shown detached in Figure 2, the bearing which it is desired to machine when this chuck is being used being indica ted at D.

Another form of mechanism particularly intended for use when machining cam shafts is shown in detail in Figures 16 to 21. Referring to these figures, indicates the drum fixed at one end to the lathe spindle 3 and at its other end carrying the workclamping mechanism. In this form of the device the mechanism comprises'a clamping member 151 shown detached in Figure 18 having a cut away portion forming an extension 152 to which is pivoted a clamping jaw 153 (shown detached in Figure 17). The pivot pin 154 between the jaw and member passes through

mating perforations

155 and 156 in the clamping members and is a close fit therein. The member 151 also has a perforation 157 counter-bored at 158 to receive loosely the shank and head, respectively, of a pivot bolt 159. This pivot bolt is pivoted closely in a key 160 mounted to slide in a transverse guideway 161 in the rear face of the member 151 and it also passes closely through a perforation in the end wall 162 of the drum 150 and has a nut 163 threaded on its inner end. This permits the member 151 to move bodily lengthwise of the key 160 and also permits it to pivot about the )in 159 as an axis, this construction furnishing a floating connection for the member 151 to the end of the drum 150. The free end of the clamping jaw 153 may be urged about its pivot 151 toward the mating clamping member. For this purpose a bolt is shown as pivoted at 171 between the ears 172 on the member 151 and carries threaded on its outer end a knurled knob 173 adapted to engage behind a pair of lugs 174 projecting from the free end of the jaw 153, these lugs defining a slot 175 between them in which the shank of the bolt 170 may lie. The adjacent faces of the

members

151 and 153 maybe notched out to conform somewhat to the shape of the piece of work to be engaged thereby, this being indicated more particularly in Figures 17, 18 and 19. Means are provided for urging the free end of the clamping jaw toward clamping position, this means, as shown, comprising a pin 176 slidable in a perforation 177 in the member 151' and urged outwardly by means of a spring 178 seated in this perforation and reacting against a plug 179 threaded in the opposite end of the perforation 177. The outer end of. the pin 176 engages a face 180 formed on the jaw 153.

These clamping

members

151 and 153 may be held against floating with relation to the drum 150 and for this purpose the extension 152 of the member 151 is formed with a large perforation therethrough and the jaw member 153 is formed with a similar perforation 186 terminating in a counterbored portion 187, the

openings

186 and 187 as shown being somewhat elongated to permit considerable movement of the clamping jaw 153 relative to the locking member. This locking member comprises an axially movable bar or rod 190 having a head 191 at its outer end seated within the opening 187 in the jaw Its shank 192 extends loosely through the perforation 185 and through a sleeve 193 keyed in the drum in the same manner as the locking rod .70 in the form of mechanism heretofore described.

Against the inner end of this sleeve 193 is a ball thrust bearing 191 and threaded on the shank 192 on the opposite side of this thrust bearing is a collar 195 in which is engaged the inner end of a handle 196. By rocking this handle it is evident that the rod 190 may be reciprocated to bring its head into clamping engagement against the base of the counterbored portion 187 and urge the jaw and member against the end face of the drum to prevent further floating of the clamping mechanism. This mechanism is released when the collar 195 is rocked in the opposite direction, by means of a spring 197 seated in a socket 198 in the opposite end of the locking rod 190 and bearing against a pin 199 which engages against the inner wall of the opposite end portion 200 of the drum.

The outer end wall 162 of the drum is of the shape indicated best in Figure 21, having a perforation 201 therein through which the pivot 159 extends and a depression 202 to receive the inner end of the pivot 154 and its fastening nut 203, and having a perforation provided with a key slot at 205 t slidably receive the sleeve 193.

' A further modification is shown in Figures 22 to 28. Referring to these figures,

210 indicates the drum attached to the end of the spindle 3 and this drum carries on a pivotal floating connection similar to those hereinbefore described a clamping member 211-. To this member is pivoted a jaw 212 on the pivot 213 which jaw may be urged toward the clamping member by means of a threaded socket element 214 engaging the jaw and threaded over an eye bolt 215 pivoted at 216 to the member 211. The member 211 is rovided with a spring pressed counterbalance pin 217 reacting agalnst an abutment 218 fixed to the drum as in the first form of mechanism described and the clamping mechanism may be fixed against floating by means of an axially movable headed rod 220 having a similar action to that already described in connection with other forms of chuck. In place of the head of this rod acting directly against a part of the clamping mechanism in this embodiment, additional frictional hold is effected by the use of a plurality of rings 221 and terbored portion and their inner diameters 222 interposed between the head of the clamping rod and the face of the counterbored ortion 223 in which this head extends. The rings 221 as shown have an internal diameter closely fitting the shank of the rod 220 and their outer circumferences are considerably smaller than the counterbored portion. The rings 222, on the other hand, have their outer diameters a snug fit in the counsomewhat greater than that of the shank of the clamping rod, these

rings

221 and 222 being positioned alternately axially of the clamping rod. The rings 221, therefore, are held with the clamping rod during the floating movement of the work-clamping mechanism, while the rings 222.1nove with the clamping mechanism and relative to the clamping red, the two sets of rings overlapping each other. When the head of the clamping rod, however, is moved axially it presses all these rings together and against the base of the counterbored portion, thus taking advantage of the frictional hold between the rings as well as that against the base of the counterbored portion.

In this form of the device, also, the rear end of the 'clampingrod is shown as pass ing into a socket 225 on the inner end of the drum where a pair of nuts 226 thereon furnish a stop to determine the outward limit of motion of the rod tending to release the clamping mechanism. The rod is normally urged to released position by means of a pin 227 seated in an axial opening therein and pressed outwardly against the end wall of the spindle 3 by means of a spring 228 positioned within this socket. In this form also the floating mounting of the member 211 is provided by the use of a key 230 in which of the member 211which is provided with an enlarged perforationi233 to receive the pivot pin as shown in Figure 24.

Also, (see Figure 22),

removable wear pieces

250 and 251 ma be fixed to the clamping member, each or these wear pieces as shown having a shank 252 and'253 which is made fast in a perforation in its respective clamping'element. A modification of this is shown in 'Fi ure 28 in which the wear piece 260 is use this being formed of a cylindrical bar which fits in a mating socket 261 in the clamping element, this socket being more than hemi-cylindrical in cross sect1on so as to retain the wear piece therein from removal except by movement parallel to its axis. It may be held from removal in this direction by means of a set screw 262 passing through the clamping element and engaging it at its inner end. The end wall 270 oi the drum is somewhat similar to the outline shown in Figure 21 and has a perforation 271 to receive the pivot pm 231 and its securing nuts, a threaded opening 272 to receive the abutment plug 218, and a perforation 273 having a keyway" 274 to receive the locking rod.

Having thus described certain embodiments of this invention it should be evident to those skilled in the art. that certain changes and modifications may be made therein without departing from its spirit or scope as defined by the appended claims.

I claim:

1. A device of the class described comprising a drum attachable at one end to a machine spindle to rotate therewith, means for rotatably supporting said'drum adjacent to its opposite end, said drum being hollow to permitwork to extend axially therethrough and to be centered relative to said spindle,

means floating on said opposite end foiu.

and to be centered relative to said spindle,-

lneans floating on said opposite end for clamping work extending through said drum, and means extendin and lying within said drum actuable to fix said clamping means to said opposite end and to release the same, said drum having an opening through its side through which said fixing and releasing means is accessible.

3. A device of the class described comprising a rotatable support, work-clamping members floatingly carried by said support, and means for clamping said members against floating movement. I

4. A device of the class described comprising a drum attachable at one end to a machine spindle, work-clamping mechanism fioatingly carried on. the opposite end of said drum and engageable with work extending into said drum in cooperative relation to said spindle, and means for clamping said mechanism against floating movement.

5. A device of the class described comprising a drum attachable at one end to a machine spindle, work-clamping mechanism fioatingly carried on the opposite end of said drum and engageable with work extending into said drum in cooperative relation to said spindle, a headed rod slidablc through said opposite end and freely through said mechanism, and means for movingsaid rod axially to clamp said mechanism against floating movement bet-ween said head and drum end.

6. A device of the class described comprising a drum attachable at one end to a machine spindle, work-clamping mechanlsm fioatingly carried on the opposite'end of said drum and engageable withwork extending into said drum in cooperative relation to said spindle, a headed rod slidable through said opposite end and freely through said mechanism, means for, moving said rod axially to clamp said mechanism against floating movement between said head and drum end, and means normally urging said rod in the'opposite direction to release said mechanism.

7. A device of the class described comprising a rotatable drum, work-clamping mechanism floatingly carried by said drum, a headed rod having a close sliding fit in a perforation on said drum and a loose sliding fit in a crforation in said mechanisnn and means or urging said rod axially to clamp said mechanism against said drum to hold said mechanism from floating relative thereto.

8. A device of the class described comprising a hollow drum attachable at one end to a machine spindle, a work-clamping member having a transverse slide-way therein, a key slidable in said way, a pivot extending through said key and-the opposite end of said drum, a work-clamping jaw pivoted to said member, means to hold work arranged axially of said spindle and extending within "said drum clamped between said jaw and member, and means actuable to clamp said member against said opposite end preventing relative motion thereof.

9. A device of the class described comprising a drum attachable at one end to a spindle to rotate therewith, a work-engaging member having a transverse slideway therein. a key slidable in said way. a'pivot extending through said key and the opposite end of said drum, a jaw pivoted adjacent to one end of said member, saidjaw and memher being positioned to engage opposite sides of work extending into said drum axially of said spindle, means .to draw said jaw toward said 'member to clamp the work, a member extending lengthwise through said drum and loosely through said member and having a head positioned outwardly of said member, and means for moving said headed member axially to bring said head against said work-engaging member and hold said work-engagin member frictionally against the end of said drum.

10. A device of the class described comprising a drum attachable at one end to one end of said machine spindle to rotate axially therewith, said drum being hollow to permit work held in axial alinement with said spindle to extend therethrough, a workclamping member having a pivotal and sliding connection with the opposite end of said drum, a clamping jaw pivoted to said member, means to draw the free. ,end of said jaw toward said member to clamp the Work therebetwcen, an element extending longitudinally through said drum and having a head outwardly of said other end, and means within the drum for reciprocating said element to bring said head into position to hold said clamping member against movement relative to said drum and to release the same.

11. A device of the class described comprising a drum attachable at one end to one end of a machine spindle to rotate axially therewith, said drum being hollow to permit work held in axial alinement with said spindle to extend therethrough, a work-clamping member having a pivotal and sliding con nection with the opposite end of said drum, a clamping jaw pivoted to said member, means to draw the free end of said jaw toward said member to clamp the work therebetween, an element extending longitudinally through said drum and having a head outwardly of said other end, and means within the drum for reciprocating said element to bring said head into position to hold said clamping member against movement relative to said drum and to release the same, said drum having an opening therethrough through which-said reciprocating means is accessible for manual operation.

12. A device of the class described comprising a rotatable drum. work-clamping mechanism floatingly carried by said drum. said drum having a perforation, a headed rod closely fitting said perforation and slidable axially therethrongh,a socket in said mechanism having a larger perforation through its base through which said rod loosely passes, rings fitting closely in said socket. the internal diameters of said rings being larger than said rod, other rings arranged in said socket alternately to said first mentioned rings, said other rings closely fitting said rod and of smaller internal diameter than said socket, but overlapping said first mentioned rings, and means for moving said rod axially to bring its head against said rings to clamp them against each other and to the base of said socket and said member against said drum to prevent fioating movement thereof.

13. A device of the class described comprising a rotatable drum, a work-clamping member floatingly pivoted adjacent one end to one face of said drum, a clamping jaw having one end pivoted to said member, means to clamp work between said jaw and member, means for counterbalancing the weight of said member and jaw about said floating pivot in one angular position of said drum, and means to clamp said member to said drum to prevent relative floating thereof.

14. A device of the class described comprising a rotatable drum, a work-clamping member floatingly pivoted adjacentone end to one face of said drum, a clamping jaw having one end pivoted to said member, means to clamp work between said jaw and member, means for counterbalancing the weight of said member and jaw about said floating pivot in one angular position of said drum, said means comprising an abutment extending outwardly from said drum, a plunger slidable in a socket in said member and engageable with said abutment, and a spring in said socket back of said plunger.

15. A gage for determining the axial position of a crank shaft relative to a chuck which comprises a block having inclined opposed faces engageable between the checks of a crank portion of said shaft, and a portion spaced from said faces and engageable with a face of the chuck.

16. A gage for determining the axial position of a crank shaft relative to a chuck which comprises a block having inclined opposed faces engageable between the cheeks of a crank portion of said shaft, and a plurality of surfaces engageable with a face of the chuck at opposite sides of said shaft.

17. A gage for determining the axial position of a crank shaft relative to a chuck which comprises a block having inclined opposed faces engageable between the cheeks of a crankportion of said shaft, a plurality of surfaces engageable with a face of the chuck at opposite sides of said shaft, and a face engageable with another portion of the shaft.

18. A gage for determining the axial position of a crank shaft relative to a chuck which comprises a block having inclined opposed faces engageable between the checks of a crank portion of said shaft, and three faces arranged about one of said inclined faces engageable with the face of the chuck.

19. A gage for determining the axial position of a crank shaft relative to a chuck which comprises a block having inclined opposed faces engageable between the cheeks of a crank portion of said shaft, three faces arranged about one of said inclined faces engageable with the face of the chuck, and a face engageable with another portion of the shaft. 1

20. In combination with a chuck havingmcans for clamping acrank shaft adjacent to a crank throw, of a member engageable between the cheeks of a crank and against said chuck to fix 'an axial position of said shaft relative to said chuck.

In testimony whereof I have afiixed, my signature.

JOHN E. LOVELY.