US1698254A

US1698254A - Power chuck

Info

Publication number: US1698254A
Application number: US7896A
Authority: US
Inventors: Jr Edward P Bullard
Original assignee: BULLARD MACHINE TOOL Co
Current assignee: BULLARD MACHINE TOOL Co
Priority date: 1925-02-09
Filing date: 1925-02-09
Publication date: 1929-01-08
Anticipated expiration: 1946-01-08

Description

Jan. 8, 1929. 1,698,254

E. P. BULLARD, JR

POWER CHUCK Filed Feb. 9, 1925 21 2 T a: 31 19 T 86 Q 4 Sheets-Sheet l 28 4'22 5 84 2 7 I 93 l 83 29 100 i 30 Z 80 INVENTOR. ,Edwardjflullaral, .71."

A TTORNEYS.

Jan. 8, 1929.

E. P. BULLARD, JR

POWER CHUCK Flled Feb. 9, 1925 Wd W u 4 l. wry; v 5a 1 Q I, w T w w BY L ATTORNEYS.

POWER CHUCK Filed Feb. 1925 E. P. BULLARD. JR

Jan. 8, 1929.

INVENTOR.

Edwardfflullaralr Jan. 8, 1929. 1,698,254

E. P. BULLARD, JR

POWER CHUCK Filed Feb. 1925 4 Sheets-Sheet 4 IN VEN TOR.

ZazbardZBallard, Z2:

' ATTORNEYS.

Patented Jan. 8, 1929.

UNITED sures-1 1,63,254r PA ENT Q HCEE EDWARD P. BULLARD, an, or s'rna rrorin oonnnorroor; ASSIGNOR To THE BULIiARD MACHINE TOOL CQMPANY, or zanrnenron'r, CONNECTICUT, AICORPORATION or 0011-" rownn oli-UoK.

np lieat ionlfile d February 9,1925. semi Nb. 7,896.

This invention relates to I an improved chuck and operatingmeans thereforp and particularly a mechanical chucklng mechanism for turning or'spindle machines, the

present application being a division, in part,

of my application Serial Number 680,180,? filed December 12,, 1923. It will be under stood that the' invention, according to the present embodiments, maybe used with various types of machines, as multiple or single spindle turning machines, stationary or rotatable drills, or the like. I

An object of the invention is tofprovide a chucking mechanism operatedfby"the power of the machine, and whic'h may be controlled with facility and precision. A

further object is to provide a' mechanism which will be positive in operation, will operate at adjustable predetermined gripping pressures, and which will stop automatically as the chuck jaws reach the limits of their open 'or clos'ed positions; and fur-. thermore, to insure such stopping at all times, irrespective of any actions ofthe operator, as for instance, when he holds the operating lever n either opening or-closing,

position,-a fter the limit of such positions has been reached. I v

With the above and other objects in'view, an embodiment of the invention is shown in the accompanying drawings, and this embodiment willbe hereinafter more fully described with reference 't'hereto, and the invention will be finally pointedwoutfin the ,claims. F

sectional view of the operating means, taken along the line Fig. 3 is a horizontal sectional view,takenalong the line 3 e 3 of Fig. 1.;

Fig. 4 is a horizontal plan view of the chuck operatingv means, taken along the line 4-4 of Fig. 1, and showing the drive means therefor; I

Fig, 5 is a vertical sectional'view of the chuck and operating mechanism, according to a modified forrnof the invention;

6 is a horizontal sectional plan view of theoperating gears and drive means,

taken along the line 6'6 of Fig. 5; v

' Fig. 7 is a vertical sectional view of the partsshown in'Fig. 6,"and taken along the" line7 -7 of Fig. 8; and

Fig.8 is aside elevation, partly in section, of theparts as shown in Fig. 6. 1 Similar reference characters indicate corresponding parts throughout the several fig ures'of the drawings. The chucking mechanism constituting the present" invention, is adapted for use either in relation with 'a multiple spindle machine of the type shown in my original application, above referred to, orit'may be incorporated in a'single spindle machine. I have herein disclosed the mechanism as adapted'for either applicationf In such machines the operator must remove the finished work and replace it with a new piece betweeneach operation of the machine, and hereto- "fore with certain types of machines hchas also been required to operate the chuck aws by" means of a hand wrench, so asto first release the finished'work and then grip the new piece, which operations necessarily con; sume time, add to the fatigue of the operator, and thusreduce the efficiency of the machine. Such manual chucking"-is furthermore inconsistent with a" machine having'a continuously moving carrier, mas, much as the operator 7 must devote 1 the greater part of the time, while the tables are moving in relation to theloading sta tions, to removing'the work and replacing the same. As will be apparentfrom the following description, the operator of the present machine is only required to throw a lever, to cause the chuck jaws to open or close, the actual operation of the jaws being carried out by mechanical means.

The work carrying table isrotatably supported in

bearings

10 and 11 of the support 12, and comprises a vertical tubular spindle 18provided at its upper end withf'a'central conical portion 14, engaginga conical seat 15 of the bearing 10, and an annular. grooved flange 16 rotatably engaging. an annular ribbed portion 17 of the bearing 10.

They spindle is provided adjacent the bearing llwith a gear 18 keyed thereto, and adapted through suitable drive means "'(not shown) to rotate the. spindle, this drive means being suchas to beinoperativeduring the operation of the chucking mechanism, so that the spindle isstationary while the operator removesthe finished work and places a new piece in the chuck.

At the upper end of the spindle 13 there is mounted the work carrying table 19, secured thereto by bolts 20, and provided with radial chuck aws 2'1, adjustably secured shaped member 30 secured within the pocket by set-screws 31.- i

The nut is provided at its under side with a cylindrical recess 32, having a recessed rotatable bearing 33 therein engaged by the short arm of a bell-cranklever 34, provided with trunnions 35 having bearing in the table, the long arm of said lever being provided at its end with teeth 36 meshing with the short radiusportion of a combination toothed segment 37, also having hearing in the table. The long radius portion of the segment meshes with a vertically reciprocating rack 38 disposed in the spindle, this rack being of triangular shape to simultaneously operate the several chuck jaws, and being held against rotation relatively to the table by means of a key 39.

The rack is provided with a downwardly extending threaded shank 40 provided at its lower end with a thrust bearing 41, and engaged by a nut 42 secured within'a rotating sleeve 43, having bearing within the spindle between anti-friction ball-bearings 44and 45, disposed above and below :a collar 46 of the sleeve, and supported within a recessed portion 47 of the spindle.

The sleeve extends below the threaded shank 40 and is splined, as at 48, to the upper end of a shaft 49, extending downwardly through the spindle, and which in turn is coupled, as at 50 to a shaft 51, rotatably supported within a bracket or cage 52 bolted to the carrier beneath the lower end of the spindle.

The cage is provided at one side of the shaft 51 with a vertical shaft 53 upon which are mounted integrally connected upper and

lower gears

54 and 55, the lower of i which is of smaller diameter, while upon the shaft 51 there are provided spaced gears 56and 57 corresponding in size to the

gears

54 and 55, the

upper gears

54 and 56 being in mesh with each other. The lower gears and 57 are in mesh with an internally toothed ring gear '58, (Fig. 4),

provided at its under sidewith beveled teeth 59, and continuously driven by a beveled pinion 60. In a multiple spindle machine, the gear 58 extends about the machine .and drives the

gears

55 and 57 of each spindle. It will thus be seen that gears 55 and 57 are continuously driven during the operation of the machine, and that the gear 56'is driven through the intermediate gear 54 in an opposite direction to the gear 57. j j

The

gears

56 and 57 are provided upon each of their opposed faces with

clutch teeth

61 and 62, having beveled ends, and between these gears the shaft 51 is provided with a flanged clutch collar 63 splined thereto and having vertical movement on the shaft, said collar being provided upon its upper and lower faces with

clutch teeth

64 and 65 having beveled ends, and adapted' to be raised and lowered by mechanism to be presently described, from its normal nonengaging or neutral position into engagement with either of the

respective gears

56 and 57, to therebyiform a driving connectionv between eitherof the gears and the shaft 51.

It is obvious that uponengagement of the clutch collar with one or the

other gears

56 and 57 theshaft 51 and the nut 42 connected therewith will be rotated in one or the other directions, and that the rack 38 will be reciprocated either upwardly or downwardly, moving the chuck through the segment 37 and bell-crank lever 34,.into open or closed-position. 'As' the V collar, after it has been disengaged from one gear, from moving into engagement with the other, and thereby causing a continued openingand closing of the chuckjaws, a dash-pot movement-retarding mechanism, hereinafter more fully referred to, is connected to the clutch collar operating mechanism and effectually stops the collar from moving beyond its neutral position.

The clutch collar is engaged by the rollered yoke end of a lever 66 pivotally mounted at 67in the cage 52, and having its projected end connected to a vertical operating shaft 68. The shaft 68 is threaded at its upper end, as at 69, and extends into a casing 7 Osecured by bolts within an opening 71 of the carrier, at one side of the work carrying table, said threaded end 69 being adjustably connected by a cotter-pinned coupling72 to a vertical extension 73, having a slot 74therein, and

to which a forked'lev'ei" arm 7 5 is connected by means of a pin 76. The lever arm is' operating handle 78 isrotatably secured by means-of a nut and washer '7 9, said handle being operatively connected to the shaft, to

impart rotary movement thereto, by means of a pawl 80, having a V-shaped engaging end normallyengaged in a notch 81 provided in a flange 82'of theshaft. The pawl is normally pressed into engagement with said notch by means of a spring 83 disposed in a passage 84 provided in the handle, and adjustable as to pressure by meansof a pressure screw 85, adapted to be fixed in adjusted positionby means of a lock nut 86.

The swinging end of the lever arm 75 is provided with a V-shaped notch87 and beveled

surfaces

88 and 89 above and below said notch, and is engaged'by the V-shaped end 90 of a spring-pressed detent 91' slidably mounted in a tubular boss 92 formed in the casing. A spring 93 normally exerts an outward pressure on the detent and may be adjusted as to pressure by means of a pressure screw 94 bearing upon a cap member 95 engaging the inner end'of the spring,

said screw working through a cap screw 96 andadapted to be fixed in adjusted'position by means of a lock nut 97.

The pressure of the spring 83'is greater than that of the spring 93,so that upon movement of the handle fromits neutral or intermediate position to its operative po-- sition in either direction toopen or close the chuck jaws, the" detent will be pressed inwardly releasing thelever arm The pressure ofthe spring 83 is such, however, as to permit pressing in of the pawl and independent movement of the shaft '77; and

lover arm 7 5 in the event that the operator does not release his 'hand from the handle prior tothe automatic return of the-shaft 68 to neutral position. v

The detent 91, in addition to yieldably retaining the lever arm 7 5 in eitherits neutral or moved operative positions, also acts to move it and its associated mechanism with a quick snap action to its neutral or' operative pos1t1ons after a preliminary 1m parted movement, this snap action occurring atthe moment the point of the detentpasses the pointed ends of .the notch 87; V

In order to prevent any return movement, beyond the neutral position, which would result in successive opening and closing of the chuck aws, as above referred to, a dashpot mechanism, acting in the nature of a brake, is provided. This consists of adashpot' 98 mounted upon the upper end of the casing 70, and provided with a plunger 99 connected by a plunger rod 100 to the member 7 3 at=the upper end of the shaft 08,- ports 101 and102 beingprovided inthe' cylindrical wall of the dash-potabove and below the plunger and in communication with the interiorv of the casing 70 through the passage 103. The arrangement ofv theports prevents particles of metal produced by the machining operations on the work from on 'tering the chamber of the dash pot. As the plunger is moved to itsupper or lower position, upon movement of the operating mechanism to open or close the chuck jaws, one of the

ports

101 and 102 is closed, so that upon the return to neutral position a vacuum is produced'behindthe plunger', and I its movement is therefore retarded.

In'Figs. 5 to 8 there is illustrated an embodiment of the invention in which a modified form of chuck actuating mechanismis provided, and in which the driving means for the chuck operating mechanism is individual to a single mechanism, and thereforeespecially adapted for use with a single spindle machine. It will be understood that either of the chucks illustrated maybeemployed with either of thedrive means.

The work table19 is provided with radial chuck jaws 104, movable in'slideways in the table, in a similar manner to the first ema bodi-mentfand each provided at its under side with a" cylindrical recess 105 having a recessed rotatable bearing 106 therein en-' gaged-by the short arm of a bell-crank lever 107, provided with trunnions 108 having bearing in the table, the long arm of said lever being engaged in an annular recess 109 provided at the upper end of a slide member 110, keyed for vertical sliding movement in the central passage 111 of the table and having an interiorl-ythreaded bushing 112 secured therein. a To the splined shaft 51 there is coupled, by means of-a sleeve 113, a splined shaft 114 having its upper end threaded and engaged in the interiorly threaded bushing 112 of the member 110.

In operation, rotation of the shaft 51 in one 1 I or'the otherdirections causes the member 'to'be raised or lowered, andthrough the bell-crank opens orcloses the chuck jaws.

The drive means for continuously rotat-' ing the chuck'operating mechanism consists" of a gear 115 meshing with both the gear 55- and the gear 57, the'shaft 116 of said gear 115, whichis journaled in a suitable bearing portion 117, having a spiral gear 118 se- 1. In a chucking device, a work table, chuck jaws carried, thereby, a tubular spindle for said table, means for operating the jaws to grip and release the work including a shaft coaxial within said spindle, and rotatable with relation thereto and reversely moving gears-coaxial with said shaft, and resistance operated means for automatically disconnecting said respective gears when the chuck jaws have been opened or closed.

2. In .a chucking device, a work table, chuck jaws carried thereby, a tubular spindle for said table, means foroperating the jaws to grip and release the work including a shaft coaxial within said spindle, and rotatable with relation thereto a and reversely moving gears coaxial with said shaft, resistanceoperated means for automatically disconnecting said respective gears when the chuck jaws have been opened or closed, and means for regulating the resistance necessary to disconnect saidgears whereby a greater or less gripping action is produced.

3. In a chucking device, a work table, chuck jaws carried thereby, positive drive means for operating the jaws, to grip and release the work, and resistance operated means for automatically disconnecting said operating means at a predetermined resistance when the chuck jaws have been opened orclosed. i

4.7In a chucking device, a work table, chuck jaws carried thereby, positive drive means for operating the jaws togrip and release the work, means foroperatively connecting said operating means to operate in one or the other directions, and resistance operated means for automatically disconnecting said operating means when the chuck jaws have been opened or closed.

5. In a chucking device, a. work table, chuck jaws carried thereby, means for operating the jaws to grip and-release the work, manually operated means individually associated with said work table for operatively connecting said operating means to operate in one or the other directions, and resistance operated means for automatically disconnecting said operating means when the chuck aws have been opened or closed.

6; In a chucking device, a work table, chuck jaws carried thereby, means for op erating the jaws to grip and release the worlgvnianually operated means for operatively connecting said operating means to operate in one or the other directions, resistance operated means for automatically disconnecting said operating means when the chuck jaws have been opened or closed,

and a yieldable connecting means for said manually operated means whereby said resistance operated means functions irrespective of the position ofsaid manually operated means. i

7. In a chucking device, a work table,

chuck jaws carried thereby, a tubular s indle for said work table, a rotatable s aft coaxial within said spindle and rotatable with relation thereto adapted to be rotated in one or the other directions to open and close the chuck jaw, a pair of drive members coaxial'with said spindle adapted to be continuously drivenin forward and reverse directions, a clutch for connecting said spindle to one or the other ofsaid drive members, and manually operatable means for selectively actuating said clutch.

8. In a chucking device, a work table,

chuck jaws carried thereby, a rotatable spindle adapted to be rotated in one or the other directions to open and close thejchuckvjaws, a pair of drive members adapted to be continuously driven in forward and reverse directions, a clutch for connecting said spindle to one of the other of said drivemembers,

manually o erable means for selectively actuating sai clutch, and driving connections between said clutch and gears having cam ming surfaces adapted upon stoppage of the spindle to move said clutch to neutral position out of engagement, with said drive member.

9. In a chucking device, a work table,

chuck jaws carried thereby, a tubular spindle for said work table,a rotatable shaft coaxial within said spindle adapted to be rotated in one or the other directions to open and close the chuck jaws, a pair of spaced drive members rotatably and loosely mounted coaxially on said shaft, means for continuously driving said members in forward andreverse directions respectively, a clutch 7 member slidably keyed on said shaft between said drive members,and manually operable means for selectively moving said clutch member into connect-ion with either ofsaid drive members to rotate said shaft in one or the other directions.

10. In a chucking device, work table, chuck I\S carried thereby, a rotatable spindle adapted to be rotated in one or the other directions to open and close the chuck jaws, a pair of spaced drive members rotatablv and loosely mounted coaxially on said spindle, clutch teeth on the opposed faces of said members, means for continuously driving,

said members in forward and reverse directions, a clutch member slidably keyed on said spindle between said drive members and havingclutch teeth on its faces in opposed and loosely .mounted'coaxially on said spindle, clutch teeth on-the opposed faces of said.

said spindle iii-one or the otherdirections said beveled, surfaces of the teeth adapted upon stoppage ofthe spindle to move said clutch to neutral position out of engagement with said drive member. a

12.- In a: chucking i'device, a ,work table, chuck jaws carried thereby,a rotatable spindle adapted to be rotated inone or the other directions to open and 'c-losethe chuck jaws, a pair of gears rotatably and loosely mounted ,on said spindle, a pair of coaxialconnected gears at one side of said spindle, one of said gears beingin mesh with one of said gears oncsaid spindle,'the other gearbeing out of mesh and in the same plane as the other gear on the spindle, a driving gear meshing with and driving said non-meshing gears, whereby one of the gears on the spindle is driven in one direction and the other in reverse direction, and clutch means adapted to be "selectively actuated to connect one ,or thenotherof said gears to said spindle to drive the same in oneor. the other directions. 4 ,f 13. In a chucking device awwork table, chuck jaws slidably,mountedjthereon, avertically reciprocating jrack, gearing :between said rack and, the; chuck jaws com rising a pivoted bell crank lever having its s ort arm connected to the chuck jaws and its long arm toothed at itstend, anda combination segment having ashort radius toothed portion meshing with said teeth of the lever andra long, radius toothed portion meshingwith said r-ack, whereby said j-aws are moved to open and closedpositionas the rack is, moved in one or the other directions, and means for moving said rackselectively, in one or .the other directions. .t j,

14. In a chucking device, .a ,worktable, chuck jaws carried thereby, power..driven means, operable in forward and reversedir'ection's to'open'and close said chuck jaws, a

clutch adapted to bemoved in one or'jthe other directions to connect said power driven means to operate in forward or reverse. directions, and means for a manually operating'said clutch comprising a manually controlled member adapted to normally occupyja neutral position, movement imparting means between said control member, and clutch, said' control member adapted to be moved-from said neutral position in either dir'ecti'onto move said clutchinto either of its operative positions, and yieldable means ;for retainin said control member and: clutch in their neutral and operative positions, and adapted-to impart a quick snap movement to said control member and clutch to; movethem towtheir neutral ,andoperative positions after a preliminary applied movement,

{15; In a chucking device, a work table, chuck. jaws carried t-hereby,-power driven means operable in iorward and reversed} rections to open and close said chuck jaws, a

clutch adaptedto be moved in one or -the other directions to connect said powerdriven.

means to-operatein forward or reverse .di-

rections,and-means for manually operating sai-dclutch comprising a manually controlled member adapted to normally occupy a neutral .p osition, ,movement imp arting'means between said control member and olutch,;said controlmember adapted to be moved from said neutral position in either directionto move saidclutch into either of its operative positions, and means adapted to automaticallyreturn said clutch and control member to neutral. position upon the limit otjthe chuck jaw movement being reached.

-16, In a chucking dev1ce',;a work table, chuckaws carried thereby, power driven meansoperable in forward and reverse d1- rections to open and closesaid chuck jaws,

fa clutch adapted to be moved in oneor the, other directions toconnectsaid power driven .me ans-toioperate in 'forward and reverse directions, and means for manually operating said clutch comprising a manually controlled -member 4 adapted to normallyoccupy a neutral position, movement imparting means, betweensaid. control member and clutch, Yyieldable connection between said control member and said movement imparting means, said control member adapted to be moved from said neutral position ineither direction to move said clutch into either of its, operative positions, and means adapted to [automatically return said clutch and control member to neutral position-upon the limit of the chuck ,jawein-ovement being reached.

'- 17..In.{afchueking device, a work table,

chuck .jaws carried thereby, powerdriven' means operable in forward and reverse directions to open and close said chuck aws, aclutch adapted to be'moved in one or the otherdirections to-conne ct said power driven .means .to operate in forward and reverse d1- rect ons, and means formanually operating said, clutch member comprising a manually sa1d"clutc h,'a yielda-ble connection between said control, member and said movement imparting means, said control member adapted 'to be moved from said neutral position in either direction to move said clutch into either of its operative positions, yieldable means for retaining said control member and yieldable clutch in their neutral and operative positions, and means adapted to automatically return said clutch and control member to neutral position upon the limit of the chuck jaw movement being reached. 7

18 In a chucking device, a work. table, chuck jaws carried thereby, power driven 'mea-nsoperable in forward and reverse directions to open and'close said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to operate in forward or reverse directions, and means for manually operating said clutch membercomprising a manually controlled member adapted to normally occupy a neutral position, movement imparting means between said control member and said clutch member, a spring cont-rolled connection between said control member and said movement impart- .ing-means, said control member adapted to chuck jaws carried thereby, power driven means operable in forward and reverse'directions to open and close said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to operate in forward or reverse di .rections, and means for manually operating said clutch member comprising a manually controlled member adapted to normally occupy a neutral position, movement imparting means between said control member and said clutch member, an adjustable yieldable connection between said control member and said movement imparting means, saidjcontrol member adapted to be moved from said neutral position in either direction to move said clutch into either of its operative positions, adjustable yieldable means for retaining said control member and clutch in their neutral and moved positions, said means being of greater yieldability than said first mentioned yieldable means, and means adapted to automatically return said clutch and control member to neutral position upon the limit of the chuck jaw movement being reached.

'20. In a chucking device, a work table,

le means for retaining said chuck jaws carried thereby, power driven means coaxial with said work table operable in forward and reverse directions toopen' andclose said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to op erate in forward or reverse dlI'ECtlOIlS, and

.means for manually operating said clutch comprising a manually controlled member adaptedto normally occupy a neutral position-,-a lever for moving said clutch, and a vertically reciprocating rod extendm between said control member and said lever, said control member adapted to be moved from neutral position ineither direction to move said clutch into either of its operative positions. j Y

21. In a chucking device, a work table,

chuck jaws carried. thereby, powerdriven means operable in forward and reverse directions to open and close said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to operate in forward or reverse direc-' tions, and means for manually operating said clutch comprising a manually controlled member, a V-shaped yieldable detent for yieldably retaining said member in its normal neutral position, imovement imparting means between said control member and clutch, said control member adapted to be moved from'said neutral position in either direction to move said clutch into either of its operative positions.

22. In a chucking device, a work table,

chuck jaws carried thereby, power driven IOUv means operable in forward and reverse directions to open and close said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to operate, in forward or reverse directions, and means for manually operating said clutch comprising a manually controlled member, movement imparting.

means between said control member and clutch, said control member adapted to be movedfrom its normal neutralposition in either direction to move said clutch into either of its operative positions, and a yieldable detent having cam surfaces adapted to move said movement imparting means to neutral, or operative positions with a quick snap movement after a preliminary applied movement. I p

23. In a chucking device, a 'work table, chuck jaws carried thereby, power driven means operable in forward and reverse directions to open and close said chuck jaws, a clutch adapted to be moved in one or the other directions to connect said power driven means to operate in forward and reverse directions, and meansfor manually operatmg said clutch comprising a manually controlled member adapted, to normally occupy a neutral position, movement imparting means between said control member and clutch, said control member adapted to be moved from said neutral position in either direction to move said clutch into either of its operative positions, and means adapted to automatically return said clutch and control member to neutral position upon the limit of the chuck jaw movement being reached, and movement retarding means acting 011 said clutch and control member to limit their return movement to neutral position.

24. In a chucking device, a work table, chuck jaws carried thereby, power driven means operable in forward and reverse directions to open and close said chuck jaws, a

clutch adapted to be moved in one or the other directions to connect said power driven means to operate in forward and reverse directions, and means for manually operating said clutch comprising amanually controlled member adapted to normally occupy a neutral position, movement imparting means between said control member and clutch, a yieldable connection between said control member and said movement imparting means, said control member adapted to be moved from said neutral position in either direction to move said clutch into either of its operative positions, means adapted to automatically return said clutch and control niember'to neutral position upon the limit of the chuck jaw movement being reached, and movement retarding means acting on said clutch and movement imparting means to limit their return movement to neutral position. j

25. In a chucking device, a work table, chuck jaws carried thereby, power driven means operable in forward and reverse directions to open and close said chuck jaws,

a clutch adapted to be moved in one or the other directions to connect said power driven means to operate 1n forward and reverse directions, and means for manually operating said clutch member comprising a manu ally controlled member adapted to normally occupy a neutral position, movement imparting means between said control member and clutch, said control member adapted to be moved from said neutral position in either direction to move said clutch into either of its operative positions, yieldable means for retaining said control member and clutch in their neutral and operative positions, means adapted to automatically return said clutch and control member to neutral position upon the limit of the chuck jaw movement being reached, and movement retarding means acting on said clutch and control member to tion. I

, .26. In a chucking device, a work table, chuck jaws carried thereby, power driven means operable in forward and reverse directions to open and close said chuck jaws, a clutch adapted to be moved-in one or the other directions-to connect said power driven means to operate in forward and reverse directions, and means for manually operating said clutch comprising a manually controlled member-adapted to normally occupy a neutral position, a lever for moving said clutch, and a vertically reciprocating rod extending between said control member and said lever, said control member adapted to be moved from neutral position in either limit their return movement to neutral posidirection to move said clutch into either of its operative positions, means adapted to automatically return said clutch and rod to neutral position upon the limit of the chuck jaw movement being reached, and a dashpot acting upon said rod to limitits return movement to neutral position. i

Signed at Bridgeport, in the county of Fairfield and State of Connecticut this sixth day of February A. D. 1925.

. EDWARD P. BULLARD, JR.