US2600960A - Index fixture - Google Patents

Description

RES.

M. L. BENJAMIN ET AL INDEX FIXTURE Filed Dec. 8, 1948 INVENTORS MILTON L BY R QNKLYN E-W/l/NEN June 17, 1952 Patented June 17, 1952 V ly'li E. Wihnefi; ai'ss'lii'or'tosaid'li Application December 8, 1948,. vSerial-No" 64,116 G'Clfiiiiis? (01. 90:57)" 1 l The: present improvements relating genefally as indicatedto an indexfixture are' nor pabl x d ticularly concerned with an indexfixtiire' fgi'f 'detilojriill machine to1s--and--the1ike wherein, for xamp veil this it is:;necessar-y topredeterminedly-relatively to: tate alworkpiece and a-too1'-to position the tanner for operation-upon by the latter; onejllustra tive example is: the milling of uniformlyspaced longitudinal slotsin' -contractible colletsand the like: wherein; after theformation of glflesloh iti is necessary to index the col-let or milling. cutter for formingi the. nextslot; I I

It a primary: object of this invention toprovide an index fixture which is accurately n dexed-through reciprocationoi the movable-element of a fiuid-powei devicetherein,v Another object is to provide an index fixture r v x V in which the rota-rymemberthereof operatively: K gnoysftdthdfawings aindffirst fiio connected with a-ratchet wheeland-vpawl-mechaii ci'all'yt 'gS I Z'theft fthere'i's" shown nism is immovably locked in indexed positiorisi q q fl i r fi s Ziaffdi by means independent:ofltheratchet pawlsr @{Pfi 3} Another object is-to'proyide a; fluid pressure actuated index-fixture inewhich: the movable element of the fluid power-device when actuatedim one direction releases the aioresaid: locking: meansandi-positions one-pawl: for: engagement i with theratchetwheetwhile another-*pawlhqlds- V H Y i dzbi otided wrth' the-wheeland; which element when. actuated im v centtlie' 'fiar'ige 9 fdffii'ecfadja, an oppositedirectionmoves.the wheel tdanew c fi'dn endther'ofand w a lock nut Ill position th roug-h said one pawlgandi ata-prethreaded onto the other end thereofi said-lock determined rctative position of'the -ratchet wheel; nut beingiield; againstfit t'i fi. frmfl. adjusfedl permitsthe '1ocking;;meansto* engagether-wheel position as by niea'ns of ia setscrew l-l-radiallj? whereby; to firmly lock the latter i'n such-newly thrdfigffi lock ntl6 frictionally engaged with} indexed-position; v I I the thfeads I;2 on said. spindle. Obviously;-

Anotherobject-istojroyidean index-fixture well' l now pt fgpmjng: of,smdhousingv oilm l economical-form permitting adjust spindle 6-with complementary: tapered sections mentof the md x pe n as shown makes it possibl to'take-up any-wear? n obflect M ro a v lci w ofethei-interengagedsurtwessaridvth i ye mfl lockin adapted wedge h intelr nateailllooseneswn siich' rotary corihc on T dentalspaces intheratchet wheelandt-hus e1imi-- frontv'fidiof sziidis'pind'i 1's: t re'g natet loosenessof the parts: when-i-nan: indexed e m m posi 1011.

Another object isto provide? an 'indexfixture mg assemm in which the aforesaid movable'elementwof the fluid-power device comprises a reciprbcatmgiraclel' in? engagement with'- a gear segmentv on. the": ratchet. mechanism, said ra'ck" being in the fomt I of an" aiiii'ularly grooved rod whefeby rdtaiiy d-is' position threof abbiiit it's ownaxie-aiia iatrat F1 s; 31am 4 are sane new;

beiriaxially retained on said spindle as'by means of 1ock-mitlfland spindle'mit'fl between wli'lch nuts: said pawl support' member" I 5 and "ratche 13h wheel l 5 raredis'pos'ecl'.- Aswiil- -liereihafter e g'i f-ully appeari-ritcht wlil Wand spiiidle S stitute a driven member whereas said pawl support member operates as a driving member.

Said pawl support member |5 comprises a gear segment l8 concentric with the axis of rotation of said member and a radially projecting lug I!) to which a driving pawl 29 is pivotally mounted through the intermediary of a pawl bolt 2| threaded into said lug and provided with a snap ring 22 retaining said pawl on said bolt. The end 23 of said pawl is adapted to be engaged in one of the interdental spaces or notches 24 in the periphery of said ratchet wheel I6 and is so formed as to permit relative rotation of said ratchet wheel and pawl support member in one direction only. A torsion spring 25 around the bolt 2| having its axially directed ends fitting in holes in said pawl and lug is operative to rotate the pawl to a position with the end thereof disposed in an interdental space 24.

Bolted or otherwise attached to said pawl support member I5 is an arcuate cam plate 26 provided with a cam surface 21 engageable with the inner end 28 of a locking plunger or lock member 29 which is radially reciprocably mounted on said housing. Said locking plunger 29 is reciprocable in a bore formed in the radial bosses 39 and 3| on said. housing and is held against rotation about its own axis as by means of a set screw 32 having the point thereof slidably fitting in a longitudinally extending slot or groove 33 formed in said plunger. Said plunger is urged radially inward by means of the compression spring 34 interposed between said plunger and a cap 35 closing the outer end of the boss 3|. As shown, the inner end of said plunger 29 is slightly tapered on its opposite sides, viz. of wedge shape of included angle of 6, for example, and the end surface 36 thereof is also at an angle relative to the axis of the plunger to facilitate entry of said plunger end in the interdental spaces or notches 24 between the teeth of ratchet wheel iii. The teeth of said ratchet wheel are shaped similar to the end of the plunger so as to be complementary therewith and to wedgedly receive the wedge shaped end of said plunger. As shown, the cam surface 21 of said cam plate 26 is such that the plunger end surface 36 is free therefrom when the plunger is in looking engagement with said ratchet wheel.

As shown, rotation of the pawl support member I5 in a counterclockwise direction as viewed in Fig. 1 will effect engagement of the cam surface 21 of cam plate 26 with the inner end 28 of said plunger 29 to thereby force said plunger radially outward relative to the ratchet wheel and thus disengage the plunger from the respective interdental space 24 in said wheel.

vIn order to hold ratchet wheel |6 against rotation during such counterclockwise rotation of pawl support member Hi there is provided a spring actuated holding pawl 3'! pivotally supported on a boss 38 raised from the bottom of recess 2 in said housing I. Said last-named pawl 31 is identical to pawl 2| and arranged as shown to permit clockwise rotation of said ratchet wheel |6 through said first pawl 2| and support member l5. In the case of pawl 31 the bolt 2| on which the pawl is pivoted is threaded into a plate 39, said plate being secured to boss 38 as by screws 49 passing through elongated holes in said plate and threaded into boss 38. By so adjustably carrying pawl 31 it can be accurately positioned with reference to pawl 2| and to the interdental spaces ,24 inratchet wheel IS.-

The lug IQ of said pawlsupport member I5 is engageable with a stop pin 4| in said housing to limit the extent of counterclockwise movement of said paw1 support member I5, said stop pin being insertable in any one of a plurality of openings 42 whereby the indexing movement may constitute, in the form of the invention illustrated, the angle between 2, 3, 4, and 5 teeth of the ratchet wheel.

Oscillation of said pawl support member l5 in opposite directions is effected by reciprocation of the movable element 43 of a fluid power device, said fiuid power device as herein illustrated comprising coaxial cylinders 44 and 45 formed in housing of different diameters and a movable element 43 in the nature of pistons 46 and 41 respectively reciprocable in said cylinders and having a common piston rod 48 therebetween formed with annular grooves 49 of shape for engagement with the teeth of gear segment I8 of said pawl support member I5. Obviously with an arrangement as shown the rotary or lateral disposition of said piston rod 48 and pistons 46 and 41 does not effect any misalignment between the grooves 49 and the teeth of the gear segment |8 as would be the case if a common gear rack were substituted for the annularly grooved rod 48. It will be evident that in lieu of a piston rod provided with annular grooves 49 the same may be provided with a worm of shape for engagement with helical teeth of a gear segment, such latter arrangement being desirable in some instances as where it may be necessary to change the relationship of the rod 48 relative to the support member l5.

From Fig. 1 it can be seen that admission of fiuid under pressure through the port 50 of the head 5| of cylinder 44 will cause piston rod 48 to shift toward the right and thereby rotate pawl support member l5 in a counterclockwise direction until lug l9 engages stop pin 4|. Such counterclockwise rotation of the pawl support member i5 causes similar rotation of cam 26 and consequent withdrawal of the locking plunger 29 from between the teeth of ratchet wheel l6. During' such counterclockwise movement of the pawl Support member l5, pawl 2| thereon passes over the teeth of the ratchet wheel and the other pawl 31 holds said ratchet wheel against counterclockwise rotation with said support member.

Now, when fluid under pressure is admitted into cylinder 45 through the port 52 in cylinder head 53 the resulting lefthand movement of piston rod 48 effects clockwise rotation of pawl support member l5 and corresponding clockwise rotation of ratchet wheel 6 through the driving engagement of pawl 2| with said wheel and the passing over of pawl 31 over th teeth of the ratchet wheel. During such rotation of pawl support member I5 the cam surface 21 of cam plate 26 permits compression spring 34 to urge locking plunger 29 into wedging and locking engagement in the particular interdental space 24 of the ratchet wheel then opposite the inner end 28 of said plunger. Thus, such clockwise rotation of ratchet wheel I6 correspondingly rotates spindle 6 and the tool or workpiece supporting member adapted to be connected thereto. The parts of the fixture are locked firmly in such indexed position until fiuid under pressure is again admitted to actuate the piston rod 48 toward the right as previously explained.

With respect to Fig. 3, when air or like compressible fluid is employed for actuating said fluid power device it is preferred that an air flow control valve 54 be included in the piping system to cause the p-iston rod 48 to move with adesiredslovvness ina lefthand direction to minimize shock on the end 28 of locking plunger 29 and to" permit relatively rapid movement of thepiston rod 'in a righthand direction. In Fig; 3 the arrow 55' denotes-the direction of fiow of pressure fluid *from a compressor, and the numeral Slide notes a, threewayselector valve for selectively connecting cylinder 45 tothe pressure port- 51' or to; the exhaustport 58;

'I'i e'fiowcontrol'valve: 54*as hereinillustrated comprises; aneedlevalve 59 and a check valve GOc nnectedin parallel whereby when-"the valve 56= is inytheposition show-n, pressure fluid canonlyaflow through the; restricted" passageway oi nee le. valve 59; to cylinder" 45; thus effecting shifting-erred 48 towardthe-left withthe. dc;- siredslowness; such lefthand movement being possible; byreason oi" the larger diameter of cylinder 45 as compared with cylinder 44 to which latter cylinder the, pressure line 6!" is; o stan y: c nn ted; Qn the Qtherhand, when valve, 56' is actuated, to connected cylinder 45' toexhaust, thewfiuid. acting on piston 46 urges rod 48. toward the right, such righthand move.- ment, Qf 'said rod being at desired rapidity in. viewflof therelatively free. exhaust of fluid from cylinder 45'. through both the. check valve. 60 and, needle... valve 59- Hbwever, when. hydraulic. oil or like liquid is employed, as. the motivatingfiuid for the fluid power. device. the; piping diagram. should be.

mqdified.asrillustrate d in Fig. 4. With a liquid pressureinedium, ithas been found that the flow control valve Mean be dispensed with and a foun-wayvalveBZ- can be; substituted for the valve,.56 fordirecting fluid under pressure from pumpv P to one. cylinder and: discharging the, fluid.- from' the other cylinder; into reservoir: ass

For convenience rigidly mounting the index fixture, the; housing, I thereofis formed with ears or;1u gs;'6-3 and withaibase portion 64.

From, the; foregoing description of the construction and operation of an illustrative embodiment of this invention it will be apparent to thos e, skilled in the art to devise various schemes for operating the valves 56 and 62 by means of cams or the likein timed relation to the movements of 'the' slide or the equivalent of a machine tool. operaticnsjnvolyed. in the-slotting, of collets for. example; ares:

l'). lndege collet, a. part revolution about; its:- central..,axis-;=.

(2); Engage. cutter and. collet-and shiftrelavtively in axial direction to form a slot in said collet from one end toward the other end;

(3) Disengage collet and cutter;

(4) Index collet to next position;

(5) Engage collet and cutter and shift relatively in opposite axial direction to form another slot; and

(6) Disengage collet and cutter.

Such operations are repeated until the desired number of slots are formed in the collet. Inasmuch as the present invention is only concerned with an indexing mechanism no specific controls have been disclosed for efi'ecting other relative movements between a workpiece and tool.

Furthermore, insofar as the primary features of this invention are concerned the ratchet mechanism may be variously modified including for example the provision of an internally In essence, the successive.

toothed ratchet wheel. with cooperating Dams; and locking memberand a cam track for: actuat ing the locking member in both directions lieu of the cam-plate--26 and" spring 34;

In any event there is herein disclosed a-unique formof index fixtureor a most elemental-con struction but yet efiicientlyoperating toac curatel-y'index' andto immovablyhold; angindexed-position. Also,- the fluid pressure operat,- ing means is such that -the locking of the-drivenv member in an: indexed positiondoes not entaili the application of undue. forces onthe locking member.

Other modes of applying j the principle of the,- invention may be employed, change beingmade as regards" the details describedi provided the; featuresstated in any ofthe; following-claims; orthep equivalentof'su'ch; be employed:

We therefore particularly-point outanddisztinctly claim as our invention:

1. In anindex fixture, the comination witha. ratchet mechanism comprising a driven memher, and a driving member movable in opposite directions having a one-way driving. connection with. said driven; member, of' a. housing, said, driven member comprising, a spindle rotatable. in said housing and a ratchet. wheel non-rotatab': 1y fixed on. said. spindle, said, driving member. comprising a. pawl. support. member rotatably mounted on said spindle. adjacent. said wheel, and adriving pawl on said. pawl support. member. engageable. in the in-terdental.v spaces in. said wheel when. said pawl support member is, rotated in. the. direction of such, one-wayv drivin con.-

w nection, a,-.positively holding pawl in said. hous ing operative-to hold said wheel against. rotation ina direction opposite .tosuch, one-way driving,

connection, a, locking plunger' in said housing movable, into and out. of locking; engagement. with said wheel, and. a camon said pawl sup,- port member operative. todisengage; said locks ing plunger fromsaidwheel. upon rotation of; said; pawl support member: and driving; pawl. thereon in a-direction opposite to its; one-way. driving; connection with said; wheel, and. spindle.-

2.. In an index fixture; the combination with: a 1 ratchet; mechanism. comprising a. driven; mem-a.

ber, and: a driving member movable in opposite; directions-having a. one-way driving. connections.- with .saiddriyen; member,.. of: a; housing-,.,saidz. drivenw member. comprising :a spindlesrotatableaine said housing and. a. ratchet?wheelgnonrrotatablvx fixed on said spindle, said driving member com. prising a pawl support; member: rotatably mountedion:saidispindleaadjacentsaidgwheel;and.

a driving pawlion said pawl -supDort;me-mben en1-= gageable in the interdental spaces in said wheel when said pawl support member is rotated in the direction of such one-way driving connection, a positively holding pawl in said housing operative to hold said wheel against rotation in a direction opposite to such one-way driving connection, a locking plunger in said housing movable into and out of locking engagement with said wheel, and a cam on said pawl support mem-, ber operative to sheet engagement of said looking plunger with said wheel upon predetermined rotation of said wheel and spindle by said pawl support member and driving pawl.

3. In an index fixture, the combination with a ratchet mechanism comprising a driven member, and a driving member movable in opposite directions having a one-way driving connection with said driven member, of a housing, said driven member comprising a spindle rotatable in said housing and a ratchet wheel non-rotatably fixed on said spindle, said driving member comprising a pawl support member rotatably mounted on said spindle adjacent said wheel, and a driving pawl on said pawl support member engageable in the interden-tal spaces in said wheel when said pawl support member is rotated in the direction of such one-way driving connection, a positively holding pawl in said housing operative to hold said wheel against rotation in a direction opposite to such one-way driving connection, a locking plunger in said housing movable into and out of locking engagement with said wheel, and a cam on said pawl support member operative to disengage said locking plunger from said wheel upon rotation of said pawl support member and driving pawl thereon in a direction opposite to its one-way driving connection with said wheel and spindle, said locking plunger being provided with a locking wedge shaped end portion, and said wheel being provided with a complementary notch for receiving such end portion of said lock member.

4. In an index fixture, the combination with a ratchet mechanism comprising a driven member, and a driving member movable in opposite directions having a one-way driving connection with said driven member, of a housing, said driven member comprising a spindle rotatable in said housing and a ratchet wheel non-rotatably fixed on said spindle, said driving member comprising a pawl support member rotatably mounted on said spindle adjacent said wheel, and a driving pawl on said pawl support member engageable in the interdental spaces in said wheel when said pawl support member is rotated in the direction of such one-way driving connection, a positively holding pawl in said housing operative to hold said wheel against rotation in a direction opposite to such one-way driving connection, a locking plunger in said housing movable into and out of locking engagement with said wheel, a cam on said pawl support member operative to disengage said locking .plunger from said wheel upon rotation of said pawl support member and driving pawl thereon in a direction opposite to its one way driving connection with said wheel and spindle, and means for rotating said pawl support member in opposite directions comprising a gear segment on said pawl support member, and a cylindrical rod reciprocably supported in said housing and provided with a series of annular'grooves in mesh with the teeth of said gear segment.

5. In an index fixture, the combination of a housing, a ratchet mechanism in said housing comprising a driven member rotatably supported by said housing, and a. driving member rotatable in opposite directions having a one-way driving connection with said driven member, and a lock member mounted in said housing for reciprocation radially into and out of engagement with said driven member, a spring in said housing constantly urging said lock member toward said driven member, and a cam on said driving member operative to engage said lock member and move the same radially out of engagement-with said driven member upon rotation of said driving member in a direction opposite to its one-way driving connection with said driven member, said lock member being provided with a locking wedge shaped end portion, and said driven member being provided with a complementary notch for receiving such end portion of said lock member.

6. In an index fixture, the combination of a housing, a ratchet mechanism in said housing comprising a driven member rotatably supported by said housing, and a driving member rotatable in opposite directions having a one-way driving connection with said driven member, and a lock member mounted in said housing for reciprocation radially into and out of engagement with said driven member, a spring in said housing constantly urging said lock member toward said driven member, and a cam on said driving member operative to engage said lock member and move the same radially out of engagement with said driven member upon rotation of said driving member in engagement with said driven member-j MILTON L. BENJAMIN. FRANKLYN E. WINNEN.

REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 1,404,243 Stewart et a1. Jan. 24, 1922 1,840,300 Archea Jan. 12, 1932 1,909,766 Johnson et al May 16, 1933 2,261,052 Coflin et a1 Oct. 28, 1941 2,262,103 Laessker Nov. 11, 1941

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