US2408491A

US2408491A - Work holding fixture

Info

Publication number: US2408491A
Application number: US511590A
Authority: US
Inventors: Elwin M Strickland
Original assignee: ALBERT F WALL
Current assignee: ALBERT F WALL
Priority date: 1943-11-24
Filing date: 1943-11-24
Publication date: 1946-10-01
Anticipated expiration: 1963-10-01

Description

members. Y

WORK HQLDING FIXTURE.

`El6vinfM. -`stfik1ana, Detroit, mchglassign ,er l

one-half to Albert F. Wall, GrossaPointe,`

Mich.

A1m1icat-ion` November 24, 1943, serial j v olalms.

This invention relates to a work holding xture and more particularly to a fixture for generating true spherical shapes or contours. I In certain mechanical devices balland socket joints are used in link connections to transmit No.. 511,590 j i n oscillating the bally jcn'fsoclnetl member-,about motion from one member to another. Consider-z able difficulty has been experienced because of the virtual impossibility of. .forming accurate matching surfaces between theball and socket socket the cutting'edge of the tool must be maintained accurately in .alignment with the center.

line of the axis of the rotating member, andthe,

itis virtually'impossible toremove them. `These.

marks may be reduced somewhat by` polishing; but since-the polishingmarks also extend'in Vthe same direction, the diiculties are not 'eliminated but merely reduced somewhat; These concene;

trically extending tool marks cut through Vthe oil lm employed to 'lubricate the joint and cause binding and galling ofthe surfaces of the'ball and seat members.v

I have found that-these dimcumesfcan-be overcome only by. operating vthecutting tools vand polishing members at differentl and-preferably constantlychanging angles t`o the surface of the'` ball or socket members as the grinding or polishingoperations progress toprovidev smooth 'spherical surfaces freefrom tool marks. IJ-' l Y 'l' An object of thisinventionv istherefore to'provide a work holdingxture forvlgeneratingftru'ei spherical shapes.l y Y A furthercobject ofwthe inventionresides"inr the provision of. a work holding x'turefor gen! erating true v spherical shapes,l Ywherein lthe icutlf ting `or polishing tool and thefwork"Trevolveirela-/ tive to each other and simultaneously: oscillate' in; two intersecting planes to prevent-the y formatl'o'f of tool marksY in a single directionontli Work."

Another object is to providean improved ball or socketforming machine lhaving apworkgholder mounted for rotation relative to ia cutting-or,

These difficulties varise from-the fact that in forming the surface'of the ball orrthef ball or socket carry- Y tersecting-oppositely disposed axes. a

Still another object of the in venticnis to provide an economical method of accurately forming spherical ball and socketmembers freefromtool.m"arks.z f i .f

A furtherobject resides inthe provision ofan improved holder 'for maintaining a ball-1in an accurate position relative to a cutting or polishing membernf y Other objects and advantages of this invention will be apparent from the following detailed description considered in connectionwith the accompanying drawings, submitted for purposes of illustration only and not intended to dene the scope of the invention, reference beinghad for that purpose to the subjoined claims.

In the drawingswherein similar reference characters refer to similarparts throughoutthe several views:

Fig. r1 isla plan View of a work holdingxture embodying the present invention;v Fig. 2 is a side elevationof thejdevice illustratedin Fig- -1. Fig. V3 is asectional view taken substantially on the staggered line `3---3 of Fig. 2 lookinginthe direction ofthe yarrows.v

Fig.4 is a sectional view of abuttingtoolholden- Fig. 511s Van fend elevationpartly in section,

takenl substantially on theline 5 5y of Fig. 4 looking in the direction of the arrows.

Fig. 6 isafragmentary side elevationalview of a modified `form of a cutting element.- Fig. 7 is a view similar to Fig. 6 showing a still;

further modified j-forI I 1. l

f Fig. 8is a fragmentary sectionallview illus-- trating the application of the invention to the formation of spherical sockets.

Fig. 9 is a fragmentarysection alfview illustratfving an improved methodof holding a ball during the forming or polishing operations.

f constructionY and arrangementof partsillustrated -inthe accompanying; drawings, since theinvenpolishing tool, and whereinthe work holdervis mounted for oscillation about. intersecting vertical and horizontal axes, i f

Yet a further objectresidesnltheprovisioni cutting or-polishing; member and simultaneously tion iscapable of other embodiments and ofbeing practiced or. carried out lin variousWays.v

Also itis'to be understood that they phraseology or tenninologyemployed herein 'is for .the-purpose of description and not of li mita'tion.`

Reierlllsy n OW- to fthe f embodiment of the inh v ention illustrated' in iFigs. V1: to 5 itjwill'be noted vthat a work carryingtable or base'l I0 isernounted on a-support IZ'bymeans of transverse andllongitudinally extending ways I4 andv I6 re'spectivee ly whereby-*the worktable ylllfmay be; movedl transversely iorlongitudinally'relative to a cuttercarrying member I8 mounted on a suitable support.

A vertically extending vyoke 20 having spaced arms 22 carried by a shaft 24 is journaled in the table I and is mounted in spaced oppositely disposed bearings 28 and 23 positioned in the plate I0 and in a housing 30 secured to and projectg ing beneath the table I0. The shaft 24 isprovided with a ring gear or worm 32 meshing with a worm gear 34 journaled in the housing 30. The worm gear 34 may be driven by a flexible-shaft 36 to rotate the shaft 32 and spaced arms`22 of the yoke 20 about a vertical axis. Suitable reversing mechanism may be provided to oscillate the arms 22 back and forth over a desired predetermined arc. One suitable reversing mechanism comprises a bearing block 69 supporting one end of the shaft 58. The shaft 88 is provided with a hand wheel 1I adapted to be actuated by a lever 13.

A work carrying spindle 38 is mounted in a yoke 40 having spaced arms 42 journaled on stub shafts 43 carried by the arm 22 for oscillation about the horizontal axis dened by the upper ends of the arms 22 of the yoke carrying spindle 38 comprises a chuck 44 adapted to engage and hold the projecting arm 48 of a ball 48 to accurately hold the ball in a predetermined position with the center of the ball positioned at the intersecting axes of the arms 22 and 42 of the

yokes

20 and 48 respectively.

The chuck 44 is provided with an extended shaft 50 having a ring or pinion gear 52 positioned in a housing 54 clamped to a cylindrical barrel 56 surrounding the shaft 50. A worm gear 58 driven by a exible shaft 80 is journaled in the housing 54 to engage and rotate the pinion gear 52 to rotate the ball 48 about the intersecting axes of the arms 22 and 42 respectively.

One of the stub shafts 43 is provided with a ring gear or worm gear 62 positioned in a housing 64 and meshing with a worm gear 86 driven by a flexible shaft 68 and a suitable reversing mechanism such as a wheel 38 having an actuating member Y4I secured to the shaft 36 journalled in a suitable bearing 31 to oscillate the work holder 38 and yoke 40 about the horizontal axis of the arms 22 of the vertically positioned yoke 20.

A suitable source of power such forv example as an electric motor is carried by the plate I8 and is provided with a shaft 12 adapted to drive the exible shafts 36, 60 and 68 to rotate the ball 48 about the longitudinal axisfof the holder 38 and to simultaneously oscillate the ball about the vertically and horizontally intersecting axes of the yokes and 40.

The cutter carrying member I8 may be provided with a driven shank 14 having a body portion 16 supporting spaced cutting or polishing members 18 as more clearly illustrated in Figs. 4 and 5. The cutter members 18 may be yieldingly urged into engagement with the surface of the work by means of calibrated springs 18 controlled by manually operable screws 8|.

The operation of this embodiment of the invention is as follows. The projecting arm 46 of the ball 48 is positioned in the work rengaging chuck 44 with the center of the ball in alignment with intersecting axes of the arms of the yokes 20 and 40 respectively. Y

The transversely and longitudinally extending ways I4 and I6 are actuated to align the surface of the ball 48 in a desired cutting relation with reference to the rotating` cutting elements 28. The work i 18 carried by the projecting arm 14 of the cutter carrying member I8. The motor 10 is then operated to drive the flexible shafts 38, B0 and 68. The flexible shaft 60 drives through the worm and Worm gears 58 and 52 respectively to rotate the ball 48 about the axis of the cylindrical barrel 56. The surface of the ball 48 is engaged by the rotating cutting elements 18 to grind the surface 'of the ball.

Simultaneously with the rotation of the ball relative to the cutting or polishing elements the ball is oscillated about the intersecting Vertical and horizontal axes. The worm and worm gears 32 and 34 oscillate the yoke 20 about the vertical axis, and the worm and Worm gears 62 and 66 oscillate the yoke 40 about the horizontal axis of the yoke 20.

The cutting elements thus are constantly moved relative to the surface of the ball 48 and do not form concentric tool or polishing marks on the surface of the Work in a single direction as is customary in ball or socket grinding machines heretofore employed.

It will be understood that if desired a polishing member may be substituted for the cutting element 18 in the embodiment illustrated in Figs. 4 and 5. It will also be apparent that other types of cutting or polishing members may be substituted for the cluster of cutting elements illustrated in Figs. 4 and 5.

Suitable reduction gearing may be employed to control the rates of oscillation of the ball 48 about the intersecting vertical and horizontal axes as the ball rotates to Imaintain a desired relation between the oscillating and rotating movements.

Fig. 6 illustrates a different type of cutting element wherein a substantially flat plate having angularly related cutting teeth 82 is carried by the projecting arm 14 of the tool Vholder to engage the surface of the ball 48.

If desired a cutting or polishing member may be carried by the chuck 44 to rotate and oscillate in the manner discussed above, and the ball or socket member to be carried by the member I8. If this expedient is resorted to, it will be Vapparent that the center of the ball or the socket should be positioned at the intersection of the arms 22 and 42 of the yokes 28 and 40 respectively.

Fig. '1 illustrates an embodiment of the invention wherein a'diierent type cutting or buffing tool 84 is carried by a rotating shaft 88 projecting from the cutter carrying member I8.

Fig. 8 illustrates the application of the inven- I tion to the formation of a socket 88. An arm carried by a member 92 having a socket 88 therein may be positioned in the holding chuck 44. A cutting tool 95 on a shaft 98 carried by the tool carrying member I8 may project;l into Ysocket 94 to iinish the surface thereof. As ysuggested above both members may be rotated in opposite directions while one memlber oscillates in the opposite planes discussed above to effect the desired finish of the surface of the socket 94.

Fig. 9 illustrates the application of the invention to a ball |00. The ball may l'be positioned in the resilient holding end portion |02 of a support |04. The portion |02 may -be formed of rubber and the portion |04 of metal. The holder may be secured` in the holding chuck 44 of the work carrying member as illustrated in Figs. l to 3. The holder` |04 may be hollow Vas illustrated at |06 to subject the surfacev of the ball to vacuum to hold it in a predetermined position as illustrated. When one side of the ball' has been contoured as desired, the vacuum may be released and the ball moved to expose a different surface for contact with the cutting or polishing members. i

The embodiment of the invention illustrated in Fig. l0 is similar in many respects to that illustrated in Figs. 1 to 3. Corresponding parts have therefore been given corresponding reference numerals with the addition of 100.

A one-way brake |51 interposed between the rotating shank |50 and a non-rotating member |69 is provided to hold the rotatable shank Ida and` ball |48 from rotating with a high speed cutting or bufiing wheel |1| fixed to a rotating shaft |13. A hand wheel is provided to actuate the one-way brake |81 through suitable gearing and rotate theshank |50 and ball |48 against the cutting or bufiing wheel I`|| to expose a dierent surface of the ballto the wheel.

The operation of this embodiment of the invention is as follows: The shank |40 of the ball |48 is clamped in the chuck |44 by actuation of the hand wheel |65 to position the center of the ball |48 at the intersection of the axes of the arms |22 and |42 of the partial yokes |20 and |40. The surface of the ball is then moved into contact with the surface of the cutting or bufling Wheel |1| by actuation of the wayson which the table ||0 is supported, and the wheel |1| is rotated.

In this embodiment the ball |48 is actuated manually about the intersecting horizontal and vertical axes and is rotated on the axis of the shank |46 as the surface of the ball is contacted by the finishing wheel 1|. The formation of tool marks in' a single direction on the surface of the ball is thus prevented and an accurate and smooth surface free from toolmarks may readily be formed. l.

It will be apparent that this embodiment may be employed in the formation of sockets as illussecond yoke about the transverse axis of the first l yoke, a work holding chuck carried by said second yoke, a rotatable finishing toolr positioned to engage the surface of a piece of work carried by the chuck at the intersection of said yokes, and means to oscillate the first and second yokes about the specified axis. 1

'3. A work holding fixture comprising a yoke having vertically extending arms, spaced arms pivotally connected to the vertically extending arms of the yoke, a chuck carried by the spaced arms to position a piece of work at the intersection of the spaced arms with arms of the yoke, a finishing tool positioned to engage the work, gear means to oscillate the yoke about a vertical axis, gear means to oscillate the spaced arms about the intersection of the arms of the yoke, and means to rotate the nishing tool relative to the work.

, 4f. A work holding fixture comprising a base, a yoke journaled in the base and having vertically extending arms, a Work carrying yoke having spaced arms pivotally connected to the vertically extending arms of the first mentioned yoke, a chuck in the work carrying yoke to position apiece of work at the intersection of said arms, a rotatable member carrying the chuck, a ro-tatable finishing tool positioned to engage the surface of the work in ther chuck, worm and worm gear means to oscillate the first mentioned yoke about a vertical axis and to rotate the work carrying yoke about a horizontal axis and exible means to drive the worm and Worm gear means to rotate the work against the rotating finishing tool and to simultaneously oscillate the Work about vertical and horizontal axes intersecting at the center of the Work.

5. A work holding fixture comprising two yokes each having spaced arms, pivotal connecting means between said arms, a work holder carried by one of the yokes to position a piece of work at the intersection Vof the yokes, a vfinishing tool positioned to engage the work, means to rotate the work holder, and means to oscillate said yokes about vertical and horizontal axes.

6. A Work holding fixture comprising a yoke having a vertically extending arm, an arm pivoty i ally connected to the vertically extending arm trated in Fig. 8 or complete balls as illustrated in Fig. 9. s

I claim:

1. A Work holding fixture for forming spherical surfaces comprising two yokes having spaced arms, connecting means between said arms, means to oscillate one of the yokes about its longitudinal axis, means to oscillate the other yoke about theV of the yoke, a chuck carried by the second mentioned arm to position a piece of work at the intersection of said arms, a finishing tool'positioned to engage the Work, means to oscillate the yoke about a vertical axis, means to oscillate the second'mentioned arm about the intersection of the arm of the yoke, means to rotate the finishing tool, and one-way driving means to rotate the work relative to the finishing tool.

7. A work holding fixture comprising a base, a vertically extending arm journaled in the base, a work carrying arm pivotally connected to the vertically extending arm, a chuck in the work carrying arm to position a piece of work at the intersection of said arms, a rotatable member carrying the chuck, a rotatable finishing tool positioned to engage the surface of the work in the chuck, and means to oscillate said arms and to rotate the chuck carrying rotatable member to rotate the work against the rotating finishing tool and to simultaneously oscillate the Work about axes intersecting at the center of the Work.

ELW'IN M. STRICKLAND.