US2354970A - Work holder - Google Patents

Description

A118- 1' 1944- F.'G. voLKEL 2,354,970 w WORK HOLDER w Filed Nov. 10, 1943 Snnentor FRA/VK G. VOLKEL,

Patented Aug. 1, 1944 UNITED sTATES PATNT oFFic o voikelros. Machinewoi'ks,LosAnge1es,oaiif.,i i a copa'rtnership consistingmof FranlrG. Volkcl and Robert C. Volkel My invention relates. to'a work holder, andthe embodiment disclosed hereinl is a work holder andsize; gage particularly adapted for holding radio crystals while they. are being ground, lapped, or otherwise abradedv to size.

In'order that the utility an'd features and advantages of my invention may be readily understood, brief reference will be made to the requirements of certain crystals used in radio. Certain radio equipment requires crystals of rectangular shape and about 15 to 40/ 1000 of an inch thick. The four perimetric edges of the crystals must be accurately to size within 2 to 4/1000 of an inch. The form of my invention disclosed herein is designed to hold a multiplicity or' stack of crystals while the edges are' being abraded to size.

-It is an object of my invention to provide va work holder and size gage inothe general' shapeof a rectangular prism having work receiving slots or cavti'es at the corners in which the work to be .abraded is secured in such a manner .thattwo edg'eszof the work project outwardlyat the-corners of the rectangular prism on two sides thereof, and the work holder has side walls which ,constitute gaging surfaces. In using the work holder and size gage of my inventi'on, the work, which may be radio crystals or other' pieces to be abraded tolsiz'e, is supported in the slots or cavities forme'd at the corners of the work holder and is applied to the abr'ading wheel with one sidev or gaging surface of the holder parallel to the surface' of the abrading wheel. The work is abraded away' until thev side or gaging surface of the holder touches the abrading wheel. The work holder is then repositioned so that another side is adjacent the abrading wheel and the work projecting from this other side is abraded vin the same manner. asV previously described. When all workin the worlrv holder has been properly abraded. the work is then removed from the work receiving slot and the two ground edges placed in the work receiving slot of a finishing work holder againstlthe wall thereof, this leaving two .unabrade'd' edges' projecting outwardly fromthe work holder.

It is another object of my invention to provide a work'holder which has a support body and blocks removably secured thereto to form work receiving slots, the support body and blocks being so shaped that all surfacesmay be ground accurately to size, and in which those 'surfaces which take the Wear may be hardened so'asto .be wear resistant. i

It is another object of my invention to provide aworksupport in which there is a central support bodylwhich:y supports all other parts inraccurate elignment-W v- It is; astill further object of my invention to provide a work suppprtrcomprising a support body and removable blocksl which 'form work receiving slots, whichv blocls may be readily removed replaced,V or resizedto vary the size of 'the work re'oei'ving slot and thus Vary Ithe size to which the work will be ground..

By virtue of the preceding object of my invention, it is possible to readily adapt a 'work support to different sizes of work merely by replacing or resizing certain of the blocks: It is possible to adapt. the Work support to 'hold' larger or smaller work, as desired'. Also, when wear occurs, such as by the gaging: surfaces'being Worn. away due to repeated contact With.. the abrading device, it'is possible to remove to resize and replace Vthe blocks',-' thus salvagin'g the work holder which might otherwise' be us'elesslf it is another olejem;v of ymy inventio-n to provide awlork holder oonprlising a body and blocks' secured. theretoin which the blocks have accurately forfned coengag'ing faces' whereby a plurality'v ofblo'c'k mutuallylicooperjte or' interlock in order to preven't 'displacement of any .one block. By

virtue of this arrangement; any'force-'ten'dingi to displac) or disalign any one'block is'not-o yi'ijesis'ted, by the seourin'g ;means which -sre resl the block to`l the body, butfdue' to' cbengagementor' I interlockin'g' with other blocks it is also resisted by' these; other block's'. This arrangemeht gives a 'veryrigi'd and strong 'structure' which does not rquire the use of doweli pin's.

providera worki holder; of the; gene ;Character I pfoifnted outfi in the Vprec'eding' parariph' inlpvvhic'h the workreceivingslot has av recess rgroove ,Other `obj ects ;andadvantages of my invention I' w' e brought' out'lduring the. courseofth'following detaileddescription of the work holder and size gage Vfor support-in'g radio crystal's during the abrading process; .which zembodim'ent Iv have ChOSensolelyifor the'- purposeof illustrating' my.

inventionjits' utility.. and" various features amd advantagesz: g

Fig. 1 is a perspective showing the w'ork and .their sec'uring screws...

holder With the work supported in place therein ready to be abraded.

Fig. 2 is a side view taken as indicated by the arrow 2 of Fig. 1.

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2 and illustrating the manner in which the Work is abraded.

Fig. 4 is afraginentary sectional .view taken on the line 4 4 of Fig. 3 showing the clamping means for removably securing the work in the work receiving slot.

Fig. 5 is an enlarged fragmentary sectional view illustrating the manner in which the blocks may be reground to resize or salvagethe work holder.

are' advanced inwardly the Work is clamped in Fig. 6 is a fragmentary sectional view showing bevel blocks which are employed where a relatively small size work receiving slot is to be'provided.

Referring to the drawing in detail, the numeral IB is a support block having the shape of a rectangular prism which has four sides ll which are--ground accurately to size but need not be hardened. At each corner of A.the body IO there is formed a longitudinal groove orrecess |2.

Removably secured to the sides ll are blocks in the shape of rectangular prisms, which blocks are accurately ground to -size'and are preferably hardened. These blocks are^indicated as intermediate blocks 14 and -end `blocks IS and These blocks are removably secured to the body Ifl by any suitable securing means, such as Allen head cap screws I'l. i i

In the form of work holder illustrated there is one intermediate blockremovably secured to each side of the body IO. Each block has edge walls 20, and these edge walls terminate adjacent the corners of .the body ID, as illustrated best in Figs. 3 and 5. The adjacent edge walls of adjacent intermediate' blocks cooperatetoform work vreceiving cavities or ,slots ,at,.,.the lcorners of lthe body [0, these workpreceiying slotsbeing indicated by the numeral 2 l. p The work holder `illustrated herein is intended to enable the; .w0.rk or crystals,25 .to begroundto square shape, and therefore the, edge walls v ,defining the sides of the Work receiving slots 2 I vare,positioned atdright anglestoeachother.V i. A .'IfheV endblpss .15 are Short blekef a .length substantially the\width of the sides ll, while the end blocks IB are ofVV a length equivalent to the width of the sides of the body' andthe ithickness of the two end blocks l5. Theend block lHi forms end walls 23 of the work receivi'ng slotsj2l';

The outer surfaces of either the intermediate or end blocks, and preferably the'outer surfaces i of both; constitute gagin'gjsurface's 24;"and the manner in which these gagingsurfaces 2ll arev employed to control the dimensions'to'which the work is abraded will be pointed outV when the operation of the work holder is'described." i

The blocks Id, [5, and |6 /have coengaging faces 24a which cause what I term an interlocking of the blocks. 'Itwill'be seen v'that the lblocks are' each separately secured to the `'body-'and that the faces 24a of adjacent blocksmutua'lly coengage' Any tendenc'y'for'one blockito'be moved or displaced isresisted not only by the securing screws l'l'of that-particular block, but also'by the securing screws of adjacent blocks. .Therefore, notwithstanding the fact that each of=the blocks is an: individual. part, each block is, nevertheless, held in positionnot only by.its particular securing screws, but also by adjacent blocks place.

As explained heretofore, the form of my invention shown in the drawing is intended to support Vradio crystals 25 during the grinding process. Therefore, in explaining the operation of my invention I will refer to its use in this connection. As previously pointed out, the radio crystals 25 are of general rectangular shape and are usually between 5 and 40/10000 of an inch thick. The crystals 25 are stacked and are placed in the Work receiving slots, as illustrated in the drawing, and, as shown in Fig. 3, the crystals 25 are so positioned that the two inner walls thereof engage the walls 20 defining the work receiving slots, whereafter the clamping screws 26 are then adjusted inwardly to clamp the crystals firmly in the position described. In view of the Vball and socket joint between the clamping screws 26 and the pads 28, the pads while being pressed against the crystals can adjust themselves to the surfaces of the crystals and breakage from misaligmnent is eliminated.

It will be noted in Fig. 3 that the inner corners of the crystals, which I-will designate by the numeral 30, extend into the recesses IZ formed at the bottom of the work receiving slots. By providing these workreceiving slots, any unevenness or burrs at the corners of the crystals are given adequate 'clearance and will not interfere with'the'crystals, being caused to contactlthe walls 20. Also, if the crystals are not exactly rectangular in shape but slightly lozenge shape. the clearance or relief at the inner corners or bottoms of the work receiving slots enables the crystals to be extended into the work receiving slots to a greater distance than there would be if there were no recess at the bottoms of the slots, and in this way better fitting of the crystalsand less wastage of material are effected..

The work holders are of such a size thaty they may be manually handled by the workman. In using the work holder it is manually positioned adjacent the abrading surface 40 of an abrading wheel 4| so that the gaging surface M is substantially parallel to the abrading surface '43. It will be seen that two stacks of work 25 at two adjacent corners of the work holder have edges which engage theV abrading surface. The operator fapplies the necessary pressure to cause the edges of the stacks of work to be abraded away.gThe workman Watches the abrading action| veryicarefully, and when the adjacent gaging surface V2,4 contacts the abrading surface ,4d thewo'rkrnan removes the assembly from contactQwith vthe abrading surface. Since the blocks Jlto;l |6 ;inclusive are hardened, they will notbe worn' away very rapidly,,and if the operator'isfvery careful during the grinding operation the gagingsur faces will remain substantiallyA to size :or within satisfactory tolerances over a period of time.

After grinding the edges of the stacks'ofywork along one side of the work holder, the work holder. isthen; turned and the abrading'process is repe'ated at this other side; f operator repv fat's this process until the edgesof all four stacks of 'crystals have been abraded. i 1

flThe' clamping screws 'are' then'release'd'; the work removed, afnd the' stacksfof crystals are then positioned'in workjreceivingjslots of 'a work holder which isused for'finishing and therefore hasl slotsj'which are slightly *smaller fin size; 4 *The stacks 'of crystals are positioned in'the'work're'- ceivingslots of the finishingwork holderf'so vthat the accurately'ground'edgesfengage'thewalls 25 of the slotsfleaving the `two rough'edges' of` each crystal projecting outwardly beyondjthegagin'g surfaces. After vcla'rnping thestacks of crystals in'plac'e the'operator then abradesthef extendin'g edges of "the crystals, 'and whenl the''operation,v

to size' within 1 to 2/1000 'offaninch g 'Asa specific example of the use of my invention in grinding aspecific size of crystal, I give the following.` The crystals to; be ground'arey .575 inch square. The first holder in which the crystals are placed has slots which have a depth of .535 inch. The crystals project outwardly .035 inch on two sides, and when ground these two sides are ground flush with the sides of the work holder. The second work holder or finishing work holder has slots .515 inch in depth. When the crystals are placed in thisv finishing work holder two edges project outwardly .020 inch which, when ground away, leave a final finished crystal which is .515 inch square.

From continued use of the work holder of my invention, the gaging surfaces 24, being at instances brought into contact with the abrading wheel, will be worn. In my invention, however, this wearing may be readily compensated for, as illustrated in Fig. 5. For example, when the surface 24 wears down to a level indicated by dotted lines 45, which may be a distance determined as the distance at which the work holder should be resized, it will be seen that the distance A has been reduced so that the crystals will has been completed the crystals are'accurately be ground to a smaller size than before, the difference depending on the distance between the surface 24 and the surface indicated by the numeral 45. To compensate for this wear, the intermediate blocks |4 are removed and the edge walls 20 are ground away to a plane indicated by the dotted line 45 so that the distance between the dotted lines 45 and 46, indicated as B, will be the same as the original distance A between the surface 24 and the end wall 29. When the reground intermediate blocks M are reinstalled on the body the slots 2| will then have their original size and wear on the gaging surfaces 24 will have been compensated for. It will be seen that the recess |2 formed in each corner of the body l permits this salvage operation without requiring the body to be ground, machined, or otherwise varied in size.

The work holder of my invention may be changed in size to accommodate crystals to be ground of a larger or smaller size. This may be done in two ways. First, thicker or thinner blocks |4 to 15 inclusive may be used or the blocks may be narrower or wider, as desired, to change the effective distances A shown in Fig. 5 between the gaging surfaces 24 and the walls 20. It will be seen that the changes in the width of the intermediate blocks 14 may be made without making a change in the body IO due to the presence of the recesses |2.

If the Work receiving slot 2| is of substantially smaller size for the size of the body IO than i`s`illu`strated in Figs. l'togthen-a'special type of intermediate block [4 is required "'I'hi'sis il-y lustrated in Fig. 6. In Fig'. 6 the 'numeral'l represents the body'and the numerals Sa-representr'the alternative'itypesof blocks. `It' wii'l be noted that the inner corners -of the blocks 1| 4a are bevelled, as indicated' at' 65,7'80 th'at'these inner Vcorners of the blocks Ma do not coengage butiare spac'ed apart in order to provide a 'chan'- nel orgutter |2a resembling 42 in the other-;figures. 'ByV cutting-awa-y the inner Corners, V'a'si at' 611; it'isposSibIe to :have edge walls 20a which overlap' or v'project' beyond sides H* o'f the' body IO a" distance'- represented at or a greater or lesser-'distance,v if desired. vItl Lwill therefore'fbe seen thatby' virtue `of myinvention a greatf latitude in sizes of slots Vis possible and av .greater rangeof work-may be'rpe'rforrned usin'gthe' w holder ofinyinvention- 4 Although'I-'have ;illustrated'herein an er'rb ment of'my invention intended Vfor use'in lsu porting'radio'icry'stals during the s'iizingoperat-io'ri, it should be'under'stood that mylinvention may be employed fo-r supporting other work, and that various alterations and modifications may be made therein without departing from the spirit and scope of my invention as defined in the appended claims.

I claim as my invention:

1. In a work holder for holding work during abrading, the combination of a support body of rectangular cross-section; blocks secured to the sidesof said body, said blocks having edge walls, the adjacent edge walls forming work receiving slots at each corner of said body; wall means forming a recess in the bottom of each work receiving slot; and securing means for removably securing the work in said work receiving slots.

2. In a work holder for holding work during abrading, the combination of: a support body of rectangular cross-section; intermediate blocks secured to the sides of said body, said blocks having edge walls, the adjacent edge walls forming work receiving slots at each corner of said body;

Wall means forming a recess in the bottom of each work receiving slot; end blocks secured to the sides of said body, said end blocks closing the ends of said work receiving slots; and securing means carried by said end blocks for removably securing the work in said work receiving slots.

3. In a work holder for holding work during abrading, the combination of: a support body of rectangular cross-section; blocks secured to the sides of said body, said blocks having edge walls, the adjacent edge walls forming work receiving slots at each corner of said body; wall means forming a recess in the bottom of each work receiving slot; gaging surfaces provided by the outer walls of said blocks, said gaging surfaces b'eing engageable with the abrading device to gage the dimensions to which said work is abraded; and securing means for removably securing the work in said work receiving slots.

4. In a work holder for holding work during abrading, the combination of: a support body of rectangular cross-section; blocks secured to the sides of said body, said blocks having edge walls,

the adjacent edge walls forming work receiving slots at each corner of said body; gaging surfaces provided by the outer walls of said blocks, said gaging surfaces being engageable with the abrading 'device to gage the dimensions to which said work is abraded; and securing means for removalbltx; securing the work in said work receiving so 5. Ina work holder for holding work during abrading, the combination of: a central support body of rectangular cross-section having the four sides formed accurately to size; blocksof rectangular cross-section secured to the sides of said body, the four walls of said blocks being formed accurately to size, edge walls of each two adjacent blocks being spaced from each other at a corner of said bodyfand cooperating to form a work receving slot, and outer walls of said blocks being hardened and composing 'gaging surfaces for engaging the abrading device and gaging the dimensionV to which the work is abraded; and securing means for' removably securing the work in said work receivingslots.

6. In a work holder for holding work during abrading, the combination of: a central support body of rectangular cross-section having the four sides formed accurately to size; blocks of rectangular cross-section secured to the sides of said body, the four walls of said blocks being formed accurately to size, edge walls of each two adjacent blocks being spaced from each other at a corner of said body and cooperating to form a work receiving slot, there being a recess formed in the bottom of each work receiving slot into which the inner corner of said work may project; and securing means for removably securing the work in said work receiving slots.

7. In a work holder for holding work during abrading, the combination of: a supportbody of rectangular cross-section; blocks secured to the sides of said body, said blocks having edge walls, the adjacent edge walls forming work receiving slots at each corner of said body, said blocks having coengaging faces whereby adjacent blocks interlock and one block cooperates in resisting disalignment of an adjacent block; gaging surfaces provided by the outerv walls of said blocks, said gaging surfaces being engageable with the abrading device to gage the dimensions to which said work is abraded; and securing means for removably securing the work in said work receiving slots. V

FRANK G. VOLKEL.

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