US2186236A - Work-holding fixture - Google Patents

Description

Jan. 9, 1940. J, w. DEARBORN WORK-HOLDING FIXTURE Filed Dec. 8, 1938 4 sheets-sheet 1 z l 9/ IO? Jan 9, 1940 .1. w. 'DEARBORN WORK-HOLDING FIXTURE Filed Deo; 8, 1938 4 Sheets-Sheet 2 Jan. 9, 1940. 4 1 w, DEARBQRN 2,186,236

WORK-HOLDING FIXTURE Filed Dec. 8, 1938 4 Sheets-Sheet 3 Jan. 9, 1940. .1.v w. DEARBORN WORK-HOLDING FIXTURE 4 Sheets-Sheet 4 -Fled Dec.

dan um J r @Q @n formed thereon is completed.

Patented Jan. v9, 1940 oNirrDfSTATes--- rATENT Frifiit,

WORK-HOLDING FIX'rUnE John W. Dearborn, Ansonimonn.

Application December 8,'

193s, seria; No. 244,522

1o claims. (c1. en -57)' This invention relates to improvements in -work-holding iixtures and more particularlyA to that type of fixtures adapted for holding small t parts, such for instance as screwsynuts, bolts,

*I etc., vduring the operation of milling, drilling,

Another object of this invention is to provide a work-holding fixture so constructed and ar.

ranged as to rmly hold an article to be operated upon, the said vixturev having incorporatedtherein superior means for effecting the 'automatic release and ejection of the article upon the completion of the operation thereon.

"A still further object is to provide a superiorA work-holding xture having indem'ng means 'ine corporated therein whereby the positioning of v an article held by the said iiXturei'naybe accurately metk for any number of`operations noted on an indexing-ring and means whereby the said article may be eitherautomatically or manually released and ejected therefrom. Y

' Still anotherobject of the presentinvention is to provide a Work-holding iixture having superior means for releasably holding a` removable collet therein and means for permitting the readyremoval of ythesaid collet from the said work-holding iiXture for replacement' by asimilarv one of different size.

With the above and other objectsin viewgaS will appear to those skilled in theartirom thev present disclosure, this invention includes all features in the said disclosure which are novel over theprior art and whichare not claimed in any separate application. In the accompanying drawings, in'which certain'modes of carrying out the present invention are shown for illustrative purposesi Fig. 1 is a top or plan View of a work-holdin fixture embodying my invention;

Fig. 2 is a rear elevational view thereof with the closure-plate removed;

Fig. 3 is an under-side elevational view thereof; Fig. 4` is a sectional view taken on the line 4-4 of`Fig. 3; i y -Fig. 5 isa fragmentary sectional View taken, Qinv the line 5-5'vof Fig. 3;

at the outer end` ofA the vertical rpassage clearly shown in Fig. 4 of the drawings. index-ringZI is provided on itsouter peripheryl Fig. 46 is a' s ectionalkview ,taken on the line 6-6'of'Fig- 3; 1 H

Fig. y'I isa, sideelevational view of the collet detached; Y y Fig. ,8, is a ,perspective view of the detent-supporting member detached; and' Fig.' 9is a similar viewof the detent detached.

In the-embodiment of the invention` as herein ,f

chosenfor illustration, the work-holding'xture i0 includesa casing lil-provided withlegs il and Withieet lI Zzby whichjthe device maybe adjust# ably' mounted upon kany suitable bed or carriage. "Ehe-casing- I0`is formed with a centrally-located f upwardly-extending neck I3 and with a depend- `ing-.boss I4. Extending yvertically through the neck I3 and boss I4 is a bore Iwhich accommodates a sleeve I6 mounted with freedom for rotation therein andv depending fromffand forming part ofI a iiange-likehead I1. The head I'I just referred to is also provided with a verticallyextending axial passage I8 providedlat its upper or outer end with an`.outwardlytapering seat I9. f

Passing laxially. through the' passage I3 above 4referred to, is a work-holding collet 20 lincluding three, more lor less, lQoi'itwardlly-tapering spring gripping-,jaws lZI, the sai d aws being adapted to seat against. the tapered seat I9 I8 formed in the head I'ILThe I collet 20 also `includes la shank 22 wextending downwardly through the lpassage I8 and which is provided 'with slots 23 resulting in the formation of the gripping-jawsil *above referred to. Extending axially through the collet y2E) is a passagez .which at itsv upper end 25 isreduced in diameter -bolts` 21 extending therethrough into Athreaded engagement -with threaded-bores iormedin the depending-sleeve I6 of the `head Il, as is The with a series of V-shaped notches 29which, in the ed bores 3Ia, provided in thebolts 21 above re ferred to,`for that purpose. The mounting-ring 30 is provided on its outer periphery with an annular retaining-lip 32 upon the upper face of which rests an annular mounting-lip 33 formed on an operating-ring 3d encircling the said mounting-ring Sil with freedom for rotation with respect thereto, and which has. extending radially outwardly therefrom, through a clearance-slot Illa in the side wall of the casing ill, an extension 35 terminating in an indexing-handle f6. It will thus be seen from the foregoing that the head Il, index-ring 2t and mounting-ring it are coupled together for concurrent rotation, as will be later described.

Returning to the collet 2l), it will be 4seen by reference to the drawings that the said collet is provided at its lower end with coupling-lugs Sl-il arranged diame-trically opposite from each other, the said coupling-lugs being of a length less than one-quarter of the circumference of the shank 22. It will also be noted ,that the circumferential area lying between the couplinglugs 3?-31 is notched as at illu-Sla, forming stop-shoulders 38--3t and tlnust-shoulders 35i- 39.

Bearing against the upper faces ofv the coupling-lugs 3!-37 is a-collet-actuating or pressure-transmitting ring lill having a central opening provided with clearance-notches! M-ll which results in the formation of a pair'of coupling-ribs l2-l2 respectively formed at one end thereof withstop-iingers 43-43 adapted to be engaged by the stop-shoulders .t3-'38 formed at' the lower end of the collet 2li. The thickness #ll-4l vin the actuating-ring lli permits the passage of the coupling-lugs 3?-33 through the said actuating-ring to bring the upper faces of the said coupling-lugs beneath the lower surface of the coupling-ribs @f2-d2. With the coupling-lugs --Sl broughtheneath the surface `of the coupling-ribs KS2-d@ the collet Zll, and

hence the coupling-lugs 31--3'5, may be rotated substantially 96 in a counterclockwise direction, f as viewed in Fig. 3 of the drawings, so as to bring the coupling-lugs 37-37 into proper position beneath the coupling-ribs -ll. l l

As will be apparent the. coupling-lugs itltl are guided by the annular walls of the clearance notches llill and the shoulder 12a during the rotationof the collet 2t to assure the proper alignment of the said coupling-lugs 31,-31 with respect to the coupling-ribs l2-52. Further rotation of the collet will be prevented bythe engagement of the stop-shoulders 33-33 thereof with the stop-fingers it-43 formed'at the ends of the coupling-ribs l2-42, as above described. Wnen the collet has been securely coupled to the actuating-ring lll the stop-fingers it-t3 are positioned in the notches Sla- 37a their upper faces in engagement with the upper wall 31h of the said notches.

By adapting the collet 25B to be hooked beneath the coupling-ribs l2- 12 forming part of the actuating-ring ill), downward pressure imposed upon the said actuating-ring will be transmitted to the collet 20 which will in turn` be pulled Va depending-stud 5l downwardly, thereby forcing the gripping-jaws 2l forming part thereof against the seat I9 in the head il, causing the said jaws to be contracted about an article placed therein to firmly grip the same.

To provide the necessary downward pressure for gripping an article as just above described, the actuatingor transmitting-ring lil is provided with a series of upwardly-extending pressure-transmitting and coupling-pins M, preferably nine yin number, one of which elle is of a size diferent from the others for the purpose as will later be set forth. The said pins M are rigidly secured to the actuating-ring 4G. The pressure-transmitting and coupling-pins lill just referred to, extend upwardly through passages i5-lli respectively formed in the index-ring 2B and mounting-ring B to bring the upper ends thereof into position to be engaged by the heads lll of a corresponding number of actuatingplungers 6.18. The plungers it just referred to, are mounted with freedom for longitudinal movement in a corresponding number of vertically-extending spring-pockets 5S formed in the sleeve it of the head H, vas is particularly Wellshown in Figs. l and 6 of the drawings. Each plunger 58, as is shown in the iigures referred to, is encircled by a helical actuating-spring 56 which exerts a constant but yielding pressure downwardly, `the said pressure being transmitted through the pressure-transmitting and couplingpins M to the collet-actuating ring Ml for effecting tliedownward movement ci the collet 2i! for gripping an article between the jaws 2l thereof.

To effect the rotation ofthe collet 20, the actuating-ring Ml is provided on its under side with rigidly secured thereto, which supports a coupling-member 52 pivotallymounted upon a pivot-pin 53 secured to the said stud 5l. At its inner end the said couplingmember 52 is provided with a coupling-nose 54 adapted to engage the `adjacent one of the thrust-shoulders @-39 formed on the lower end of the collet 2t. At its outer end the couplingmember 52 is engaged by a helical-spring 55 constantly urging the outer end of the said couplingmernber downwardly to hold the coupling-nose 54 thereof normally in engagement with the thrust-shoulder 39 asabove described,

In the arrangements just above described, the

coupling-member 52 in `effect serves as a cou-y extension 35 `thereof has mounted upon its upper face an index-ring-actuating p-awl 56 adapted t0 engage with the notches 29 formed in the outer periphery of the said index-ring 26. The actuating-pawl 5S is rigidly secured to the upper end of a stud 51 which passes through the extension 35 with freedom for rotation therein and has its lower end encircled by a helical-spring 5B, one end of which is seated in a transverse slot 59 formed inthe lower end of the said stud 5T. The opposite end of the spring 58 is formed with a hook til which engages with a depending-pin 6l rigidly secured to the under face of the extension 35. As will be apparent, the spring 58 constantly urges the free end ofthe pawl V56 into engagement-with the outer periphery, and hence the notches'l of theindex-ring 26, to couple the` operating-ring 34 to the'said index-ring 26 for iconcurrent rotation in one direction whichas kviewed in Fig.l 3 yof lthe drawings, would be counterclock- Wise. l

tation ofthe index-ring 26 `and v'hence the head I1,y mounting-ring '36` and actuating-ring!!! which, dueto its coupledrelation to the collet by means of the coupling-member 52, rotates the 'said'icollet andthe article gripped thereby.

4,Duringfth'e return'movement of theindexin'ghandle and operating-ring 3G in av clockwise direction,"asfviewed `in Fig. 3 of the drawings, the indexing-pawl 56 moves freely outwardly,fromA engagement with thenotches 29 in the periphery` of the index-ringzii to, in effect, ratchet back over the periphery of the said index-ring,

Which-is permitted by its yielding vengagement with the said index-ring, as above described.A

During the return movement of the operatingring 34, the index-ring 26 and associated parts,

including` the actuating-ring lief and' collet ,20, remain stationary until and coupling-member 52, .again` eiectsthe rctation: of the collet 20 to a degree correspondingto any number of given notches in the indexring 25 which may be arbitrarily selected bythe operator. i

"To `prevent any inadvertent displacement of 'the'indeX-ring 26 and hence the collet iduring y the returnmovernent of the operating-ring. 3i I toits normal position, thesaid' index-ring is engaged at diametrically-opposite points by de- ,tents-EZ-SL each of which is pivotally-niountedat the inner end ofl arms {i3-63 projecting .in- Wardlythrough clearance-passages E4--S4l provided in the sidek wallsjof thecasing I0. The armsSS--SS just referred to project inwardly from andform an integral part of annular plates 651-65 rigidly securedv 'to vthe casing l. maintain the detents 62--552 iniyielding engagement with the index-.ring 2t,v helical-springs Bi--Gere provided which bear at their inner ends 'against-flanges' 'G'l-Sl formed on springplungers S18- 68 having their inner ends seated they detents 2-62. At their` outer ends, the springs BE-ES bear vagainst shoulders formed on retaining-screws 'lil-J9. It will thus be seen thatthe detente 62-62 `are held in. constant but yielding engagement with the notches 29 in the outer periphery of the index-ring 25 to prevent the rotationof the said index-ring in a cloche Wise direction,y as viewed in Fig. 3' oi the drawings, but that the said detents will yield to permit the index-ring 26 to rdebywhen the said rection, as viewed in 'the figure just vreferred to.` The tension of the 'springs 65--66 is, however, suicient to preventA the detente 62-62 from yielding under pressure exerted against themduringthe performance ofl any operation on'the y article held by thecollet.

y To effect the automaticejection and release of 'an article held by the gripping-jaws 2i oi the operating-ring 3d" l is-again rotated in a counterclockwise direction to again reffect the rotation of the index-ring la horizontal coupling-bar 9i.

index-ring isrotated in a counterclockwise di-- l 'll-1l are transversely arranged at diametrij cally-opposite v4points between the boss.. M 'and the sidewalls ofthe casing I0.

,endsl axially vbent to fit into pockets Elli--fly formed in the inner faces of the bearing-hubs f i 15-15 of the adjusting-rings 'I4-14.

As thus constructed and arranged, it willbe apparent that any'rotaticn imparted to the adjustingrings 'I4-14 will, in turn, effect lthe ten'- sion or" theksprings 'IS-19, lwhich may thereby be adjusted to any required,degreey of tension. After the desired tension hasbeenA acquired by the rotationof the adjusting-rings "M -14, the

lthe collet` 20, a pair of similarly-formed shafts The f shaftsV l Isf said rings may be `secured. in proper position against rotation `by the engagement of a retaining-finger 8l formed at the outer ends of bars 82-82 secured to the side walllof the casing l0 by means of pins 13S-$3;`

At the extreme inner end "of each of the shafts M -1I, an v,eccentric-stud 84 is providecLupon each of which ispivotallymoimte'd alifting-arm 85, as is particularly Well shown inYFig. 6 of the drawings. Each ofthe arms 85 atitsloweriree end is provided with a finger 8S vwhich'rnay engage with the under face of theadjacent actuating-ring 4l)l to raisethe same,ffor the purpose' of opening the collet. lAt itsfouter edgejopposite to the ringer 86, `each of the larins is' provided with alongitudinal'groove El linv/'hichf 'be-ars the inner end of screws 88-88 `for thepurpose of maintaining the lower dependent end of each of the arms 85-85 ,in its proper vposition for engagementv withthe actuatingring when the shafts 'll-1|, and hence ,the eecentric-studsi i3d-84, are rotated. As before'noted,' the'outer ends of the shafts `H---H extend' voutwardly through the adjusting-rings v'Ui-#i513 and have mounted thereon connecting-arms 89 and 9i), the lower ends of which are' pivctally'secured to They coupling-barI 9| has secured to one end thereof 'a chain or its equivalent 92,',the opposite end of whichvmay be secured to any stationaryr point forming part of the'particular machine upon which the xture being ldescribed maybe employed, for effecting. thefautomatic release of an article gripped by the -jawsl of .the collet 20 for subsequent ejection therefrom. As the xture, and, consequently the article held thereby, passes beneath the cuttingtool of the machine upon which the xture is vemployed by `the reciprocation ofthe bed ory carriage of the Inachine, and the required operation is performed upon the said article, vthe bar `Eli will, near the end of the stroke of the bed'or carriage, be held stationary, due to the chain lli! preventing any from lrighi'. to left, as viewed in Fig. 2y of the drawings, to effect the rotation'` of the shafts lI-'II against the tension of the springs lilthus causing the eccentric-studs lt-Slt to be raised above their normal position.

The upward movement of the eccentric-studs 84-84 as just above described, also raises the lifting-arms 85-85 pivotally connected thereto to cause the ngers St-Bt thereof to raise the actuating-ringv 40, together with the pressuretransmitting and coupling-pins i4 secured thereto, and the collet 2i?. The upward displacement of the actuating-ring it causes the stop-fingers 43-43 thereof, in engagement with the upper wall 31h of the notches 31a-tlc formed in the collet 20, to move the said collet upwardly against the tension of the helical-springs 59, which upward movement results in the jaws 2l expanding suiciently to permit the removal of the article held thereby, in a manner as will be hereinafter described.

To effect the ejection of an article gripped by the collet 2i), the bar Si has pivotally mounted thereo-n a tripper 93 pivoted upon a pivot-pin Se intermediate its ends and beveled at its forward or inner end to provide a tripping-nose Q5. As shown in li'ig.l 2y ofthe drawings, the tripper 93 is mounted above the upper face of the bar Si and is normally heldin the horizontal position, shown in the iigure referred to, by a stop-pin @S mounted in the upper face of the bar BI and with which the forward portion of the tripper normally is held in engagementby a spring 9i. The spring 9'! is interposed between the outer end ofthe tripper S3 and the upper face of the bar SI and exerts a constant effort to holdthe forward portion of the said tripper in engagement with the stop-pin 96.

The tripper .Q3 is adapted to have its trippingnose 95 engage with a tripping-lug Si? mounted upon a shaft 9S when the bar BI is in effect shifted from right to left, as viewed in Fig. 2 of the drawings as previously described. The shaft 99 is mounted in a bearing-passage Iii@ formed `in the lower portion of the casing if! and is provided at its inner end with la U-shaped head IUI which pivotally mounts a horizontally-arranged arm IIl2, as is particularly well shown in Fig. 6 of the drawings. The arm It? is pivo-tally mounted to the `head IIB! by means of a pivotpin It and is adapted, upon occasion, as will later appear, to be moved through an arc of clockwise, as viewed in Fig. 3 of the drawings. To yieldingly hold the arm m2 in the position in which it is shown in the drawings, the shaft 99 is formed with a spring-pocket IEM accommodating a helical-spring it, the said spring encircling a plunger mit, the outer end of which bears against the adjacent face of the arm i132 to yieldingly hold the latter in the position shown.

' At its free end, the arm IGZ is provided with a pivot-pin I EV! and has pivotally mounted upon the said pin av link |98, the said link being also provided at its upper end with'a coupling-stud It!! which has in turn pivotally mounted thereon an ejecting-rod IIB.

As is particularly well shown in Fig. 6 of the drawings, the ejecting-rod IIE! extends vertically into the passage 25. formed in the collet 2B and is in axial alignment therewith, its upper end terminating below the outer face'of the collet 20 in position to serve as a support for an article held by the said collet. About midway of its length, the ejecting-rod lili is provided with a downwardly-facing shoulder Iii which bears against the upper face of a plate IIE, the latter being connected to a plate II3 by pillars II4. The plate II3 is provided on its lower face with a hub I I 5 and, together with the plate I I2, serves to form a guide-bearing for the ejecting-rod I IU which passes freely therethrough. The outer periphery of the plates I I2, I I3 are notched toform chip-clearance notches I I5, as is particularly Well shown in Fig. 3 of the drawings, the said plates being mounted with freedom for longitudinal movement in the passageilll formed in theshank 22 of the collet 20. It will thus be seen that the ejecting-rod I I0 is held in its proper axial position in respect to the passage 24 in the collet ZIJ, though free to reciprocate therein.

As has been before stated, the tripper 93 mounted upon the bar 9i Aeffects the release of the article held in the jaws 2l of the collet 2 through the chain of parts including the arms 89an`d 9U, shafts 'll-1|, dependent-arms 85-85, and actuating-ring 4D. When the bar 9! is held stationary as above described, the tripping-nose 95' is formed at the inner end of the tripper 93 engages with the tripping-lug 98 to cause the latter to rotate counter-clockwise, as viewed in Fig. 2 of the drawings, against the counterurge of a spring II'I to thus rotate the shaft 99.

As the shaft 99 is rotated, the arm |02, carried by the head ISI, will also be rotated, thus causing its free end to be moved upwardly, thereby raising the ejecting-rod IIIl. Asthe tripper tcontinues its travel, the tripping-lug 98 will be swung to a ypoint where it will be beneath the lower face of the said tripper, thus enabling it to ride free of the tripping-nose 95 and assume its normal inoperative position' under the urge of the spring II'I. The tripping-lug 98 is permitted to return to its normal position, onceV it is free of the tripping-nose 95 by virtue of the tripper 93 being pivotally mounted, which allows the tripping-nose 95 at theinner endthereof toA be raised against the urge of the spring 91. The return of the tripping-lug 98 to its normal position causes the arm IDZ, mounted at the inner end of the shaft 99, to also assume its normal` inoperative position, with the result that the ejecting-rod I Il] is withdrawn to its normal position in the collet'20. j

In the construction of the tripping mechanism just described, it will be understood that the relative position of the tripping-nose 95 and the tripping-lug 98when they are in engaged position, is such that the effect of the tripping nose 95 upon the lug 98 is a short, abrupt movement, so as to, in effect, cause the ejecting-rod II Il to abruptly eject the article held by the jaws 2l of the collet 2B.. It will also be understood that l the ejecting operation takes place substantially simultaneously with the release of the article by the collet 2l).

Preferably, and as is shown in the drawings, the arm 90 is provided with a manual operatinghandle H8, so that the bar SI may be longitudi` nally moved to eifect the opening of the jaws 2i of the collet 25B. The operating-handle IIB also enables the device to beemployed. on a drillpress or the like, in which case the release and ejection o-f the article is accomplished by the manual operation of the said operating-handle.`

In the operation of the device herein shown and described, an article to be operated upon is placed in the jaws 2l of the collet 2li. Thev article held by the jaws of the collet 2G is subjected to the action of a cutting-tool and an operation performed thereon, such, for instance,

as the cutting of a ilat'face for the formation 75 j form'the thirdand fourth flats or""faces to complete the square.= VAfter the. formation of the.

' of a square." .Whentheoperation of cutting one vilat or face of a square hasxbeen completed, the Y operator -will'swing the. indexing-handle 36 the required distance, or-.the limit of movement controlledby the'clearance-slot- |061., to rotatethe index-ring one-quarter of a revolution, or sixV notches, as noted in. the periphery of the saidindex-ring, so as vto effect the. turning of the-article held byrthe collet90. The indexinghandle 36 is then returned to' its normal position, as illustrated' in thev drawings,- and the article is again subjected to thel operation of the cutting-tool to cut the second ilat orface at right f angles to the one justpreviously formed. The

above described loperation-is, then `repeated to square as just vdescribed-the operating-handle ||8 may be depressed or,l if'preferred, the automatic release and ejection may be employed, to-

cause the 'coupling-bar 0 together with the arms 89 and 90,' to 'effect the.ro-i'jation of the shafts` "TI-Jil, to thereby release and eject the article held by the ljaws2| of the collet 20' and enable* a fresharticle -to be-placed'threin.

From the foregoing, it will' be obvious that the rotation o-futhe index-ring" 26v` yfor one notch,v

willturn the collet gli of la revolution, twol notches vwill 4vturn: the icollet T15: ofv arevolution," three notches I 1/8, fourtnotches 1/6",y six notches 1@Weight notches` twelvenotches 1/2.A

` .For convenience in forming provided withstop-s'houlders |2j| and |22. The limit-pins I I9 and `|20 are` yieldingly held in place bymean's of aspring |23 `a'ccornrnodated in a bore |24 intersecting the bearing-passages in which the said limit-pins are-'mounted for reciprocation. The "spring i |23 is interposed lbetween a pair of retainingy spring-pli'ingersV |.25-.I25 adapted to bearvagainst the adjacentv limit-pins ||9 andI |20 to yieldinglyretainfthe l v said pins in either a raised .or depressed position,

Thelimitpins vHB and y|20 are adapted, when.

in their raised position, toengage 'withi'a stoppin |26 mounted in the'rside-wallof rthe casing l0 .for they purpose .of limiting'the movementv of the indexing-handle 3E 'in one direction.

When it is desired to form a hexagon, the limitpin |20 is moved into its raised position, as shown in 5 oi the drawings,.sofas-to plac'efthe upper end'thereo'f into position to engage withy the stoppin |26 when the indexing-*handle 36 'is swung toirotate the indeX-ringi, which 'rotation will be limited to one-sixthlofv airevolu'tion, orfour ynotches on the said '-indeX-wheel.` Whereupon the operating-handle 36 is returned toits vnormal-'position and again'gswung to the vlimit imposed y thereo-nby the engagement of the limit-pin |20" with the stop-.pin |25. This operationis then `.repeated the required lnumber of times to form the desired hexagon. lDuring the above'described operation, the limit-pin I9 is placed in its" depressedpor inoperative position', Athereby enabling the saidpinto'pass beneath the stop-pin |276. -To form an Octagon, the limit-pin H0v is' raisedv to bring the upper end thereof into -position to? engage with the stop-pin |26 so as to'limitthe movement `of the indexing-handle ..30 .toxonei eighth of a revolution, or.v three notcheszonthe index-wheel. The procedure -set l:forth in thefor.-

mation of' a hexagon visthenrepeated the required numberxof times tof form 1 Octagon. Itwill be'obviousthat ,thelimit-,pin .|20 maybe y v hexagons and octagons,- vthe extension35is.provided with two spaced-apart ltransverse limit-pins'l I9 and- |20 l"set for forming a hexagon and the indexing-handle 36umovedtwice for therotation of the indexring- 26" eight notches or 'one-third revo-lution,

which will'gresult in the formation' of a three-4 sided figure.

' vIn. the `"construction shown, both limit-pinsl ||9 and` |20 may be depressed at A'the same time so as to permit both the said pins to pass beheath-the.stop-pinv |26 'sogas Ito enable the indexing-handle to be swung through 90 or onequarter of a revolution, which Will vresult inthe formation.oil a four-.sided gure.

. To enable articles of varying lengthsto beheld oy the'device herein described, the `ejecting-rod I i0 may be removed by uncouplingthe link' |08 latter-'maybe bodilyremoved from within the The in which position a worksupporting rod no`t fshown) of vthe desired length may lbeclanflped therein to replace the ejecting-rodV I0.

lItwill,be understood that in employing they clamping-'arm |2l and the work-supporting rod carried thereby, that the removal of. the article fromthe collet y20 must `be effected by hand,

though the release ofvthe'said article, fromfthe 'fixturevr may be. accomplished in the manner `previously described by thejoperation-of the voperating-handle H8. It willgbe apparent that the ejecting-rod H0 may be replaced lcya similar one o-f anydesired length capable of ejecting Kthe article heldv by the collet 20, so as to' enable articles of various lengths tobe held by. the said collet.

'.To hold the collet 20 in its Vopen posltion, so

as r to facilitate its removal and replacementby one of` a `different size, a spring-blade |30' is mounted on the inner faceof a closure-plate [3| the said closure-plate enclosing thewcouplingbar 9|,. arms 89 and 00, and associatedgparts. The closure-plate |3| is provided at'its respective.

opposite lends withvthe necessary clearancenotches.y for the passage of-the handle ||8 and secured. to the casing lby meansv of suitable screws. To hold the collet 2|)` ingits open position,`the blade |30 is pressed-inwardly, as viewed in Fig. 3 of the drawings, infWhich'position-the .the coupling-bar Sl, thesaid plate being rigidly ses free end thereof may engage withfalatchingshoulder |32 provided onthe outer fac'eof the coupling-bar 9| when thesaid bar is in its coll'et-openingposition. 7With the. engagement of `the spring-.blade |30 `With the latching-shoulder '|32 whenthe coupling-bar 9| is in its collet- `opening-position, the collet `2 0 may be kept inv its open position as longfas is desired, with the pressurekthat normally tends to hold the said 'collet in its closed positionremoved. f 1

Should it vbe desired to remove the collet y20 to- 'be replaced by a similar one ofv a` different'size,

thejoperating-handle H8 is depressed torelease the tension on the saidv collet, as previously described, andthe blade |30 )engaged withthe latching-shoulder |32, as .above set forth. The coupling-member 52 is'then'disengaged from the lisy .from thesaid ejecting-rod. Withvthe uncoupling i i thrust-shoulder 39 to thereby permit' the said collet to be rotated to bring the coupling-lugs thereof intoregistration with the notches 4i-4I in the actuating-ring l to thereby permit the 'collet 2t to be axially withdrawn from the passage it in the head H. To insert a new collet of diierent size, the procedure just set forth is'reversed, that is, the shank of the collet is placed in the passage ld and the coupling-lugs S'i-f'll thereof passed through the notches li i-M 'head V! is suitably marked `as at 11a, (Fig. 1)

which mark when brought to the frontface of the fixture indicates that the coupling-member 52 is in a'position accessible to the operator. To assure the correct assembly of the head and associated` parts with respect to the actuating-ring lill and coupling-member 52 the pin 44a is employed.

As will be apparent from the foregoing, the provision of releasable collet-coupling means, such as the coupling-member 52, permits the ready removal and replacementof a collet of varying sizejwith consequent increase in eiciency and range of application to vwhich thel iixture ,may be employed.

It will thus be seen that a work-holding xture is provided for firmly holding a large variety of articles, including screws, bolts, studs, etc., for having operations performed thereon b-y any suitable tool upon the completion of which, the article may be either automatically or manually released and ejected, leaving the jaws of the collet open for the insertion of a fresh article.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all f changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein. I claim:

l.' A device of the class described, including:

a head, a collet seated therein, an actuating-ringl with which the collet is detachably connected, means for holding lthe collet in engagement with the said actuating-ring, an index-ring connected to the head, an operating-ring, a pawl carried by said operating-ring to engage with said indexring, and means for turning said operating-ring.

2. A device of the class described, including: a head, a collet seated therein and formed at its lower end with lugs, an actuating-ring formedclearance notches, an actuating-ring formed with*v coupling ribs, said ribs being less in thickness than the thickness of said actuating-ring, whereby shoulders are formed having a. diameter substantially yequal to the diameter or the clearancenotches and the external diameter of the coupling-lugs.

4. A device of the class described, including: a head, a collet seated therein, an actuatingring with which the collet is detachably connected, lifting arms on which the actuating-ring may rest, horizontal shafts having eccentric studs on which the lifting varms are supported, whereby said actuating-ring may be raised, springs tending to push the actuating-ring'downward to hold the collet in gripping position, means for turning said shafts to raise the said actuatingring, an index-ring connected to the head, an operating-ring, a pawl `carried by said operatingring to engage with said index-ring, and means for turning said operating-ring.'-

5..A device of the class described, including: a head, a collet seated therein, an actuating-ring with which the collet is detachably` connected, lifting arms on which the actuating-ring may rest, horizontal shafts having eccentric studs on which the lifting arms are supported, whereby if.

said actuating-ring may be raised springs tending to push the actuating-ring downward to hold the collet in gripping position, and means for turningsaid. shaftsv to raise the said actuatingring, whereby the collet is vmoved orclosed position. ,l

6. A device of the class described, including: a head, a collet seated therein, an. actuating-ring `with which'the collet is detachably connected,

lifting arms on which the actuating-ring may r" rest, horizontal shafts having eccentric studs on which the lifting arms are supported, whereby the said actuating-ring may be raised, pins mounted on said bottom-plate, springs mounted in the 'casing with which said pins coact to hold 5'" the'collet in gripping position, means for turning said shafts to raise the said actuating-ring, an index-ring connected to the head, an operating-ring, a pawl carried by said operating-ring to engage with said index-ring,y and means for turning saidoperating-ring. v

'7. A device of the class described, including: a head, la collet seated therein, an actuating-ring with which vthe collet is detachably connected-a gauge-rod in said collet, an ejector upon 'which said gauge-rod rests, means for moving the ejector to raise vsaid rod, an index-ring .connected tothe head,an operating-ring, `a pawl carried by saidoperating-ring to engage with said index-ring, and means for turning said operating-ring.

8. A device of the class described, including: a head, a collet seated'therein, an actuating-ring with which the collet is detachably connected,

a gauge-rod in said collet, an ejector upon which said gauge-rod rests, means for moving the vejector to raise said rod, said ejector extending through a cage comprising a plate above and parallel with the ,actuating-ring and connected therewith by pins, an index-ring connected to the head,.v an operating-ring, afpawl .carried by said operating-ring to engage with said indexring, and means for turning said operatingring.

9. A device of the class described, including:l a head, al collet seated therein, an actuating-ring with whichV the collet is detachably connected,` lifting arms adapted to engage with the actuating-ring, horizontal shafts having eccentric studs on kwhich the hangers are supported, whereby said actuating-ring may be raised, springs tending to push the actuating-ring downward to hold the collet in gripping position, means for turning said shafts to raise the said actuating-ring, a bar,

links. connecting saidbar `with. said horizontal to an open shafts, an anchor for said bar, akhandle on said.

ed, whereby said actuating-ringmay be raised,

` turning said operating-ring.

springs tending torpush the actuating-ring downward .to holdy the collet in gripping position,

means `for turning said shafts to raise the said bottom-plate, a bar, links connecting said bar with said horizontal shafts, an anchor `for said bar, -a handle on said bar, means for locking the bar to hold the collet in openposition, a kicker, a stop on said bar adapted to 'engage said kicker,

an index-ring connected to the head, anfoperat- Y ing-ring, a pawl carried by said operating-ring to engage with said index-ring, and means for 1 J. W.l DEARBORN.

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