US2752740A

US2752740A - Form relieving fixture

Info

Publication number: US2752740A
Application number: US392171A
Authority: US
Inventors: Garrett H Mouw
Original assignee: M W SALES CO
Current assignee: M W SALES CO; M-W SALES Co
Priority date: 1953-11-16
Filing date: 1953-11-16
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

July 3, 1956 s. H. MOUW 2,752,740

FORM RELIEVING FIXTURE Filed NOV. 16, 1953 4 Sheets-Sheet 1 INVENTOR. GARRETT H. MOUW ATTORNEY y 1956 e. H. MOUW FORM RELIEVING FIXTURE 4 Sheets-Sheet 2 Filed Nov. 16, 1955 INVENTOR. GARRETT H. MOUW 31L ATTORNEY y 3, 956 G. H. MOUW FORM RELIEVING FIXTURE 4 Sheets-Sheet 3 Filed Nov. 16. 1953 lllllllllllllllllllll ll L 3 m WL F MO W mH T T E R R A G ATTORNEY July 3, 1956 cs. H. MOUW 2,752,740

FORM RELIEVING FIXTURE Filed Nov. 16, 1953 4 Sheets-Sheet 4 TEE-:- 1 D 23 242 INVENTOR. GARRETT H. MOUW 235 ATTORNEY FORM RELIEVING FIXTURE Garrett H. Mouw, Birmingham, Mich., assignor to M-W Sales Co., Royal Gak, Mich, a copartnership of Michigan Application November 16, 1953, Serial No. 392,171

Claims. (Cl. 51-232) This invention relates to a form relieving fixture for positioning and moving workpieces relatively to a grinding wheel or the like in a manner whereby a given workpiece may be provided with the desired form relief, and more particularly, the invention relates to a fixture embodying means for positioning and moving a workpiece with respect to a grinder wheel whereby the workpiece :may be provided with only radial relief or with only longitudinal relief, or with any desired combination of radial and longitudinal relief; the various positions of the fixture being quickly and accurately settable for particular workpieces by simple, easy to operate adjusting means.

The forming, sharpening, or relieving of cutting tools :such as drills, reamers, taps, counterbores, and the like presents the manufacturer or user with an acute problem in that different tools cannot be made or sharpened in a manner precisely like that in which another particular tool is treated. For this reason it is essential that a form relieving fixture be flexible enough to adapt itself to the operations required for the proper relieving of a variety of workpieces, otherwise each workpiece must have a separate fixture associated with the manufacture or resharpening thereof or each workpiece must be hand worked, either of which is obviously an expensive and undesirable solution to the problem. The prior art contains many examples of form relieving fixtures but none of these has been entirely satisfactory from the viewpoint of complete adaptability to a multitude of different workpieces.

With the foregoing in view, it is an object of this invention to provide a form relieving fixture adapted to provide the proper support for a multitude of different workpieces so that each workpiece may be held and presented to a grinding or like machine in the proper individual position so as to produce a tool having the desired form and relief.

An object of the invention is to provide a workpiece form relieving fixture which is capable of supporting a workpiece relative to a grinding or like machine in such a manner that the workpiece may be provided with only radial relief.

An object of the invention is to provide a form relieving fixture which is capable of supporting a workpiece relatively to a grinding or like machine in such a manner that the workpiece may be provided with only longitudinal relief.

Another object of the invention is to provide a form relieving fixture capable of supporting a work iece relatively to a grinding or like machine in such a manner that the workpiece may be provided with any desired combination of radial and longitudinal relief.

Another object of the invention is to provide a work- 'piece supporting, form relieving fixture of simple con- :struction whose adjustments to produce a workpiece hav- :ing the desired form may be quickly, easily, and actcurately accomplished.

Another object of the invention is to provide a work- "piece supporting, form relieving fixture which is adjustable atent ice to provide a workpiece with the desired purely radial relief, purely longitudinal relief, or any combination of radial and longitudinal relief, and which is further adjust able so that a workpiece may be provided with the abovementioned types of relief in both a forward and reverse direction.

A further object of the invention is to provide a form relieving fixture which is easily converted from a longitudinally and/or radially relieving fixture to a simple, circumferentially relieving fixture.

These and other objects and advantages of the invention will be specifically pointed out or will become apparent from the following specification when considered in conjunction with the accompanying drawings wherein:

Fig. 1 is a top plan view of the form relieving fixture showing a workpiece supported thereby in proper position to a grinding wheel for that particular workpiece;

Fig. 2 is a rear elevational view of the fixture;

Fig. 3 is a side elevational view thereof;

Fig. 4 is a view partly in cross-section taken along the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 4 but taken along the line 55 of Fig. 3;

Fig. 6 is a cross-sectional view taken along the line 66 of Fig. 5.

Fig. 7 is a rear view, similar to Fig. 2, illustrating a modified form of fixture;

Fig. 8 is a fragmentary top plan view of a portion of the fixture shown in Fig. 7;

Fig. 9 is a cross-sectional view taken on the line 9--9 of Fig. 8;

Fig. 10 is a cross-sectional view taken on the line 1il10 of Fig. 8;

Fig. 11 is a cross-sectional view taken on the line 11-11 of Fig. 8;

Fig. 12 is a cross-sectional view taken on the line 1212 of Fig. 7; and

Fig. 13 is a top plan view of a slightly modified form of spindle head actuating means.

Referring now to the drawings wherein like numerals refer to like and corresponding parts throughout the several views, the embodiment of the invention shown therein for illustrative purposes comprises, in general, a base plate 10 adapted to be secured in a fixed, swivel, or other suitable manner to the bed structure of a suitable support or machine (not shown), the base plate 10 providing support for a slide disc 11 on which is supported a carriage 12 having a disc 13 providing a base for the workpiece carrying head or spindle housing 14. The base plate 10 also provides support for an arm 15 which carries novel spindle head motion actuating means 16 which are adapted to be adjustably positioned in proximity to a portion of the head 14.

More particularly, the base plate 10 of the fixture may be of irregular configuration as illustrated in the drawings and is provided with a substantially centrally located, circular recess 21) through the center of which extends a threaded, bolt receiving aperture 21. Into the circular recess20 a circular slide disc 11 is adapted to be received so as to be freely rotatable therein with respect to the base plate 10. Through the center of the slide disc 11 extends an aperture 23 through which a threaded bolt 2 may extend and engage the threads in base plate aperture 21 to secure the slide disc against the base plate.

integrally formed with the slide disc and extending upwardly therefrom are a pair of oppositely disposed, parallel, apertured slideways 25 joined at one end by a connecting block 26 so that the slideways and connecting block present a substantially horseshoe shaped configuration whose open end facilitates access to the bolt 24. The connecting block 26 is provided with a rearwardly projecting boss 27 having a centrally located spring re- 3 ceiving pocket 28 provided therein. 'lheeonnecting block is also provided with an aperture for reception of one end of an adjusting screw 29 whose function will be explained presently. I V g H Overthe slide disc 11 is disposed a carriage 12 which comprises an upper disc 30 and a lower -pl'ate 31, the two elements being integrally joined by a neck 32. At the front and rear of the lower plate 31 is a downwardly turned

flange

33 and 34, respectively, each of which is provided with a pair of spaced apertures 35 aligned with correspondingly spaced apertures in the other flange. The carriage 12 is maintained-in position on the slide disc 11 by a pair of

slide bars

36 and 37 which "extend through 'slideways 25, the ends of the bars projecting into the

flanges

33 and 34 and being fixed therein at their forward ends by suitable means suchas set screws 38.

The

slide bars

36 and 37 are freely slidable in the slidewaysZSwhich may be provided with suitable linear bearings 39, but the slide bars and carriage 12 are held in fixed, relatively immovable relation by the setscrews 38 which lock the slide bars and the carriage together.

Flange 34 is equipped with an internally threaded bore 40;into which a threaded cap 41 is'adapted to be screwed. A compression spring 42 has its ends seated in pocket 28 and in the cap 41 so as to resiliently space carriage flange 34 rearwardly from the slide disc 11. The position of the carriage 12 relative to the base or slide disc11 may be varied by means of the adjusting screw 29, which has one end thereof pinned in the connecting block 26 as at 43 'and whose other end extends slidably through flange 34. V This endof the screw 29 is threaded for reception of an adjusting nut 44 which may be turned down so as to bear against the external face of flange -34'and which may be further turned down against the flange 34 to advance the carriage forwardly against the compression of the spring 42 to increase or decrease the-distance between the connecting block 26 andthe flange 34 thereby varying the distance the carriage may travel' relatively to the slide disc. Should a force be applied to therear flange 34, the carriage will move

forwardlyfthe slide bars

36 and 37 sliding in the slideways 25 and the spring 42 being compressed between the flange 34 and the connecting block 26. When the force is withdrawn, the spring 42 returns the carriage rearwardly until contact is made either between the nut 44 and the flange 34 or until the carriage movement is arrested by other means to be explained. Referring now to Figs. 2, 4, and 6, the upper portion of the carriage 12 terminates in a disc 30 which is provided with a pair of

arcuate slots

51 and 52 adjacent the periphery. Positioned atop carriage disc 30 is the spindle head supporting disc 13 which is preferably the same diameter as carriage disc 30 and which is equipped with a pair of oppositely disposed threaded holes53 and 54.

Holes

53 and 54 are positioned directly over

arcuate slots

51 and 52 so as to receive bolts 55 which may be-passed through the slots and be retained in the

holes

53 and 54 with the heads of the bolts lying in the space between disc 30 and the lower plate 31. The purpose of the slots, fhioles, and bolts is to permit the carriage to have its po- Zsiltion angularly varied relatively to the spindle head 14 {and the construction shown permits the carriages posi- ;tion to be varied substantially 180 degrees merely by loosening the

bolts

55 and 24 and thereafter turning the "carriage 12 and slide disc 11 relatively to the head 14 and the base plate ltl. The ability of the carriage to be disiplaced' substantially 180 degrees from the position shown in the drawings enables the fixture to prese nt a :"workpiece to a grinding wheel in such a position that the :workpiece may be provided with the desired relief in a reverse direction as will be more fully explained subsequently.

To enable accurate adjustment of the carriage relajtivelyto the spindle head, one of the discs'13 or 30 may "beiprovided' with a series of' graduations '45 on its-rim and the other may have a witness line on its rim whereby the angular variation of the carriage relatively to the spindle head may be quickly and accurately determined.

Integrally formed as a part of the spindle head supporting disc 13 is spindle or workpiece supporting head 14 having a spindle 69 rotatably mounted therein by means of suitable bearings. The spindle 60 may be provided at its forward end with a collet 47, or any other suitable or desired means for engaging or holding a workpiece as will be understood by those skilled in the art.

The rear portion of the spindle 60 projects beyond the rear'end of the spindle housing 14 so as to provide a mount for an annular spacer 62 and a cam 63, the spacer 62 being fixed to the spindle 60 so as to preclude both rotational and longitudinal movement with respect thereto. The cam 63 may be fixed to the spindle 60 in any suitable fashion so as to prevent relative rotation therebetween, or the cam 63, if desired, may be secured -by suitable means to the spacer in a manner to permit the cam to be removed quickly from the spindle and another cam substituted in its stead. A retainingring 64 may be positioned on the spindle 60 rearwardly of the cam 63 to maintain the cam in the desired position on the spindle. It will be understood that the-rear portion of the spindle 60 will have suitable means'such as a hand crank 48A or a pulley 48 and belt 49 associated therewith so that the spindle may be driven either manually or by power means.

Referring now to Figs. 2 and 3, the base plate 10 is provided with a laterally disposed, dove-tailed channel 65 adjacent its rear edge. The foot 66 of an angular supporting arm 15 is provided with a correspondingly dove-tailed portion which 'fits within the channel'65 so thatthe foot 66 and'the arm 15 may 'beslid laterally across'the base plate 10. 'The'rear wall 67o'f'thebase plate is apertured in a plurality of places permittingset screws 68 to retain the arm '15 in laterally adjusted position.

On the inner face of the arm 15 is a recess 70 in which is slidably disposed a mounting block 71. One side of the mounting block 71 is angulated so as to seat in the recess 70 of the angularly disposed arm'lS and that side of the block 71 is also provided with a pair of threaded holes into which apair of screws'72, projecting through an adjusting slot'73 "in arm'15, may be threaded to hold the block 71- in vertically adjusted position. I

' Mounted atop mounting block'71 is thespindle head motion actuating means 16 comprising a bell crank75 swivelly mounted about a bolt 74, the bell crank 75 carrying a pair of freely rotatable

cam contacting rollers

76 and 77 disposed at'right' angles to eachother and revolving about

pins

79 and 80, respectively. As shown in Fig. l, roller'76 contacts-the rim of mm 63 whereas roller 77lies against the rear face of cam 63 and-it is to be noted that roller '76 is-positioned so that'inits normal position it contacts the dwell portion of the cam 63 between lobes 78. In the drawings, cam 63 is illustrated as having eight lobes 78, the number ofdobes corresponding to thenumber of flutes on the'workpiece 59- diagrammatically shown in Fig. 1. It will be understood, however, that many other'types of cams having other and different shapes and number of lobes may be substituted for the cam shown so that a given workpiece will be operated upon at the point or points desired. Obviously, the cam 63 or other cam will need to be timed with relation to the rotation of the tool mounted in the spindle head and this timing may be done in any suitable-manner known in the art.

In the position shown in the drawings, rotation-of the spindle 60'by either a manually .operated-crankbr by power means will cause the cam '63 to be rotated As one of the lobes 78 of the 'cam"63 engages :the roller '76, the bell crank 75 will berocked clockwise,I-asseen in Fig. 1, causing the roller 77 to bear against-the rear face of the cam 63. Referring to Fig. 3, the force exerted against the rear face of cam 63 by the rotation of the bell crank 75 about pivot 74 will be transmitted through the spindle head 14 to the carriage 12 so as to cause the carriage and the head to be moved forwardly or to the right, as viewed in Fig. 3, via the slide bars 36 and 37, the spring 42 being compressed between the carriage flange 34 and the connecting block 26. This type movement of the head carries the workpiece 59 longitudinally past the grinding wheel 58 to provide the workpiece with longitudinal relief. When the lobe 78 has passed the roller 76, or when the spindle is rotated in the opposite direction, the spring 42 restores the head to its original position.

In the operation just described, the initially lateral motion of hell crank 75 caused by the lobe 78 on the cam 63 has been converted to solely longitudinal motion of the head through the expedient of the slides 25 which are aligned with the longitudinal axis of the head.

If it should be desired to cause the head 14 to reciprocate purely laterally, the bolt 24 and the bolts 55 may be loosened so that slide disc 11 and carriage 12 may be rotated 90 degrees with respect to base plate It) and with respect to spindle head supporting disc 13. The amount of angular variation of the slide disc can be determined readily by observing the calibrations marked on the base plate and on the

discs

13 and 15. In the adjustment just described, the longitudinal axis of the spindle head remains unchanged; the slide disc 11 and the carriage 12 have been merely rotated 90 degrees. With the latter two elements in the desired position, the

bolts

24 and 55 may be tightened to hold the various elements in adjusted position.

With the slide disc and the carriage in the adjusted position, rotation of the spindle 60 will cause a cam lobe 78 to bear against roller 76. The bell crank 75 cannot rock, however, because the roller 77 bears against the rear face of the cam 63 and cannot displace the head because the position of the slides has been changed 90 degrees. Thus, in effect, bell crank 74 becomes a stationary support for roller 76 which bears against the lobe 78 so as to displace the spindle head solely at right angles to the longitudinal axis of the spindle head. By rotating the slide disc 90 degrees from the position shown in the drawings and by revolving the spindle 60, a workpiece 59 carried in the head 14 may be provided with solely radial relief.

It will be obvious that if the slide disc and carriage are rotated any angular distance less than 90 degrees, then there will be a compound displacement of the workpiece head both laterally and longitudinally along a line representing the resultant of the lateral and longitudinal forces enabling a workpiece to be provided with both radial and longitudinal relief in any degree of either which is desired. That is, with the carriage and slides disposed at some angle less than the 90 degrees above referred to, the rotation of the cam 63 will cause rocking of the bell crank 75 so as to exert both a longitudinal and a lateral force on the spindle head and these forces will be resolved along the line of the slides so that the motion of the head will be along the line of the slides whereby a workpiece carried by the head may be provided with both radial and longitudinal relief. Any desired degree of either radial or longitudinal relief, in combination, may be obtained by varying the positions of the carriage and slide the proper amount.

As shown in Fig. 2, the arm 15 is disposed at an angle to the vertical so as to prevent interference between the arm 15 and the spindle rotating means in any adjusted position of the mechanism 16 or arm 15. From the position shown in Fig. 2, the mechanism 16, together with the mounting block 71, may be vertically adjusted so that the amount of displacement of the spindle head may be varied to produce the desired radial and/ or longitudinal relief. In the drawings, the axis of the roller 76 is at the same height as the axis of the spindle 60 which means that at this point the displacement of the head is at a minimum both laterally and longitudinally because it is at this point that the reaction between the cam and the roller 76 is of least magnitude. Lowering of the mounting block 71 via the screws 72 and the slot 73 increases the magnitude of the reaction due to the fact that the reaction between the roller and the cam is the resultant of a lateral and vertical force as will be understood, and thus the displacement of the head will be increased so that a longer longitudinal and lateral stroke are obtained. If the adjustment of the block 71 moves roller 76 out of contact with cam 63, the foot 66 of the arm 15 may be moved laterally across the base plate 10 by loosening the screws 68 so that the roller 76 maintains constant contact with the cam in any adjusted position of the mounting block 71.

By means of the variability of the slide disc and carriage, the direction of the displacement of the workpiece head can be controlled so as to produce any desired direction and by the adjustability of the mounting block 71 via the screws 72 and slot 73, the degree of displacement can be controlled so as to provide a workpiece with any desired radial and/ or longitudinal relief. The amount of head displacement may further be varied by adjusting carriage 12 via adjusting screw 29 to increase or decrease the stroke of the carriage relatively to the slide disc 11 as has been explained.

To provide the fixture with the desired flexibility of adjustment enabling it to be used on a great number of different workpieces, the base plate 10, Fig. 5, is provided with an arcuate slot 400 and a witness line 401 enabling the base plate to have its position varied with respect to the grinding or like machine bed or support so as to present a workpiece supported by the spindle head to the grinding machine at any desired angle. For example, to provide a pointed or tapered workpiece with the proper relief, a usual screw 402 extending from the machine bed through the base plate slot is loosened permitting the fixture to be rotated relatively to the bed about the post 403 the desired number of degrees which may be read from a suitable scale on the bed via the base plate witness line. Thereafter, the screw 402 may be tightened to retain the fixture in its adjusted position.

A. particularly important feature of the instant fixture lies in its ability to hold a workpiece with respect to a grinding wheel in such a manner that a cutting edge of the workpiece may be provided with relief on its rear face. Assume, for example, that a tool such as a form milling cutter comprises a longitudinal shank provided with one or more longitudinally spaced circumferential ridges having sloping front and rear faces. To relieve the front face of the workpiece, the slides and carriage may be adjusted as hereinbefore described so that the desired forward relief on the workpiece is obtained. To relieve the rear face of the workpiece, the

bolts

24 and 55 are loosened and the slide disc and carriage rotated more than 90 degrees from the position shown in the drawings, whereupon the

bolts

24 and 55 are tightened to secure the parts. In this operation the slides and carriage will be extending in a direction diagonally rearwardly, but the workpiece itself will be extending in the original direction. Obviously, if the spindle were rotated at this point, the cam lobes 78 pushing against roller 76 would cause a binding of the bell crank 75 since it would be impossible for the rear roller 77 to push the head forwardly due to the direction of the slides and carriage. To remedy this situation the rear roller 77 may be removed from the bell crank 75 by the simple procedure of withdrawing the pin 80 and permitting the roller 77 to drop out. Removal of the rear roller alone, however, is not sufficient to cause the desired motion of the head because removal of the rear roller would permit the bell crank to rock freely without producing any head motion. This situation is easily overcome .by locking the bell crank relatively to the arm .15 and one means of locking the bell crank comprises inserting a locking pin 81 through an aperture 82 in thebell crank, permitting the pin 81 to project into an aperture drilled into mounting block 71 so as to prevent rocking motion of bell crank 75. With the rear roller removed and the :bell crank locked, rotation of the spindle 60 causes rotation of the cam 63 whereupon lobes 78 will react with roller 76 to produce the lateral component of head displacement which will be transformed into lateral and rearward longitudinal motion of the head along the axis of the slides so that the workpiece carried by the head 14 will be moved obliquely .rearwardly relative to the grinding wheel so as to provide a rear face of the workpiece with the desired forward or reverse relief.

Another feature of the fixture is its ability to be converted easily and quickly in-a purely circumferential for-m relieving fixture without using additional equipment. The fixture may :he so converted in a number of ways, one of which is to loosen set screws 68 and withdraw the supporting :arm .15 together with the actuating mechanism 16 to a position remote from cam 63. Another simple manner of conversion is to loosen screws 72 and remove the mounting :block 71'from the arm 15. Probably theeasiest way :to convert the fixture to a purely circumferential relieving fixture, however, is to turn down the adjusting screw 44 against carriage flange 34 so as to move the carriage and spindle head forwardly a distance sufiicient to prevent the rear roller 77 from contacting the face of cam '63 even when the bell crank is rocked by the cam lobes. ilf this adjustment is made, rotation of the cam will merely cause the bell crank to rock back and forth and since there .is no contact of the roller 77 with the cam, no head displacement will result and the workpiece will merely :revolve.

:Figs. 7-12 disclose a fixture having modified spindle head motion actuating means 116 and supporting means 115 therefore, but in all other respects being identical to the fixture disclosed in Figs. 1-6.

:In the modified form of fixture, the rear end of the base plate 1.0 is equipped with a laterally disposed, dovetailed channel 65 into which a correspondingly dove-tailed portion of a slide block 166 is adapted to fit for sliding movement relatively to the base plate .10. The position of the block 166 may be fixed and secured by set screws 68 as before.

Mounted atop the block 166 and secured thereto by suitable means is an upstanding, hollow, cylindrical boss 177 into which one end of a column 168 is inserted and retained by a set screw 169. Over the top of column 168 is placeda mounting block .171 having a column receiving bore 172 therein provided with a key 173 which fits into a keyway 174 in oneside of column 166 to hold the block in non-rotatable relation with respect to the column. The vertical position of block 171 relative to column 168 may be fixed at any desired height above block 166 by means of a set screw 175, and as a further precaution against relative rotation between block 171 and column 168 a dowl ,pin 176 may be used between the key 173 and the block 171 if desired.

Referring now to the mounting block 171 as particularly illustrated in Figs. 7, 8, and 10, two adjacent sides are bored for reception of the stems 200 of a pair of collars or rings 201. The interior of the stems 200 are threaded for reception of studs 203 passing into the mountinglblock 171 from the bottom thereof to securely fasten the callers in place atop the mounting block. Extending through one of the collars 201 is a roller assembly or plunger 205 comprising a shank 206 terminating at one end in a yoke 207 which provides journals for an axle 208 on which is rotatably mounted a roller 210 adapted to contact the rim of cam 63. Extending through the other-collar 201 is a second roller assembly or plunger 215 comprising a shank 21:6 terminating at one end in a yoke 217 which journals an axle 218 on which is rotatably mounted roller 220 which is adapted to contact the rear face lot can: :63. Each of the

shanks

206 and 216 may be equipped with longitudinal keys 209 and .219, respectively, adapted to slide within keyways provided in the collars 2.01 so .as to maintain

rollers

210 and 220 in an upright position as shown'in the drawings. At the end of each roller assembly remote from the roller 21-0 or 220, there is a headed

stud

221 or 222, respectively, removably received in hole provided in the

shank

206 or 216.

Those sides of the mounting block 171 opposite the sides provided with the

roller assemblies

205 and 215 are provided adjacent the edges with threaded holes 23.0 and .23 1 and there. is an additional threaded 'hole 232 disposed between

holes

230 and 231 and equidistant from each of the latter. It is important to note that the three

holes

230, 231, and 232 are disposed along an arc of a circle, the importance of which will he explained shortly in connection with .an adjustment for varying the stroke of the spindle head 6.

Mounted on :the mounting block 171 for pivotal or rocking movement relative thereto is a rocker arm :or bell crank 235. Bell crank 235 is provided with three

bores

236, 237, and 238 arranged so as to correspond to the spacing of

holes

230, 231, and .232 and as shown in the drawings a pivot pin 240 having a lower threaded neck 241 and .an upper smooth shank 242 extends through holes .232 and 238 thereby rockably mounting bell crank 235 on mounting block 171 at the center of the bell crank through the center :hole of the block. Each end of the bell crank .235 is provided with .a

rounded nub

243 and 244 which bears against the heads of

studs

221 and 222, respectively.

With bell crank 235 mounted in this manner, rotation of spindle .60 causes rotation of cam 63 whose lobes 78 bear against roller 210 and push roller assembly 205 to the right as viewed in Fig. i8. The entire assembly 205 is pushed, the plunger 206 sliding within collar 201, causing the head of stud 221 to exert .a force against the nub 243 of bell crank .235. Since the bell crank is pivotally mounted, the :force exerted against nub 243 rocks the crank about its pivot so that nub 244 bears against the head of stud 222 :to force roller assembly 215 in a forward direction parallel to the axis of the spindle 60. If the slide bars 36 and .37 are parallel to the axis of spindle 60 the displacement of the head 62 will be along a line parallel to the direction of the slides so that longitudinal relief is imparted to the workpiece by the grinding wheel. By variation-of the position of the slides and carriage relatively to the spindle head in the same manner as previously described, any desired degree of combined longitudinal and radial relief, or only longitudinal, or only radial relief may be ground on the workpiece.

One advantage obtained by the use of the embodiment shown in Figs. 7-12 is that the surfaces of the

rollers

210 and 220 which contact the cam 63 are always flatly disposed thereagainst. That is, in the form of the invention disclosed in Figs. l--6, rocking of the bell crank carries the rollers with it so that the edges of the rollers rather than their fiat rims ride against the cam. In the instant embodiment, rocking of the bell crank does not carry :the rollers with it and, therefore, the rollers may remain with their rims flatly disposed against the cam.

A further feature of the instant embodiment of the invention is the additional adjustment available with bell crank 235 to vary the stroke of spindle head 62. As previously pointed out, the three

block holes

230, 231, and 232 are disposed along the arc of a circle. The

holes

236, 237, and 238 in lever 235 are also disposed along the same arc, and this are passes through the centers of

nubs

243 and 244. Thus, there is a definite ratio of angular variation of one nub relatively to the other as pointed out below. With the bell crank 235 mounted as shown in Fig. 8, the ratio between the displacement of nub 243 to nub 244 is 1.0 to 1.0. This ratio can be varied, however, by removing pivot pin 240 from the center holes and placing it i1 one of the other pair of holes. Thus, if a greater longitudinal stroke of the head is desired, the pin 240 may be placed in

holes

237 and 230 whereupon rocking of the bell crank causes nub 244 to move one and one-half times the distance moved by nub 243, or, in other words, the ratio between

nubs

243 and 244 is 1.0 to 1.5. If it is desired to have a greater lateral displacement of the head, pivot pin 240 may be placed in the third pair of

holes

236, 231 so that the displacement ratio between

nubs

243 and 244 is 0.5 to 1.0. Obviously, the displacement of the ends of the bell crank determines the displacement of the head as has already been explained, and with the three pairs of holes disposed in an arcuate path, the ends of the bell crank will remain in position against the roller assemblies irrespective of which pair of holes constitute the pivot point of the bell crank. When it is desired to use the instant fixture to provide the rear face of a workpiece such as the previously mentioned form milling cutter, for example, with the desired relief, it is a simple matter to set the slides in the proper position relatively to the spindle head and to remove roller assembly 215 and lock bell crank 235 against rocking movement by placing a second pivot pin in one of the two end pairs of holes whereupon rotation of cam 63 imparts an obliquely rearwardly motion to the spindle head in the same manner as previously described.

Every feature present in the fixture shown in Figs. 1 to 6 is present in its modified form illustrated in Figs. 7-12. The latter embodiment, however, has an additional head displacement adjustment and also has a contact between the rollers and the cam which reduces wear and provides a smoother operation.

In Fig. 13, there is illustrated a slightly modified form of spindle head actuating means 316. With the exception of a modified form of bell crank 335 and a larger mounting block 371, actuating means 316 is substantially identical to actuating means 116.

It has been found that when the pivot point of a bell crank is disposed inwardly of the intersecting lines drawn from the ends of the crank, there is a binding tendency of the crank during rocking motion. This binding tendency is not great enough to cause any substantial interference, but it may be desirable to eliminate it completely for certain types of operations. The embodiment disclosed in Fig. 13 does eliminate the binding characteristic and at the same time combines the desirable features of both forms of actuating means hereinbefore discussed.

The binding tendency of the bell crank is overcome by extending the dimensions of the mounting block 371 in a direction outwardly from the column 168 so that the edges of the block project beyond the ends of

plungers

205 and 215. This extension of the block 371 enables a right angle bell crank 335 to be mounted thereon with the pivot points located on or outwardly of intersecting lines drawn normal from the ends of the bell crank. The central pivot point of the bell crank is provided by a pair of holes, one of which is provided in the crank as at 338 and the other of which is provided in the mounting block, both holes being adapted for reception of a pivot pin similar to pin 242. On either side of the central pivot point, there is another pivot point provided by

holes

336 and 337 in the crank and correspondingly spaced holes in the block 371. These holes in the crank and block may all be disposed along the arc of a circle so as to provide a definite ratio between the displacement of one end 343 of the crank relatively to the other end 344 thereof in the same manner as described in connection with the actuating mechanism 116.

While the invention has been shown and described in detail, it is obvious that other modifications and adaptations of the device are possible. This disclosure, therefore, is intended by Way of illustration only, the inven-- tion being defined in the appended claims.

I claim:

1. A form relieving fixture comprising rotatable workpiece supporting means, a base, said base having mounting means supporting said workpiece supporting means for reciprocating movement relatively to said base, said mounting means being variable relative to said base and to said workpiece supporting means for changing the direction of reciprocating movement of said workpiece supporting means, means for rotating said workpiece supporting means and having a cam thereon, and rockable actuating means supported by said base in engagement with said cam and rockable in response to rotation of said cam to cause reciprocating motion of said supporting means.

2. A form relieving fixture as set forth in claim 1 wherein said rockable actuating means includes a bell crank mounted on said base for rockable movement relatively thereto, said bell crank having means at each end thereof disposed at right angles to each other in engagement with different portions of said cam.

3. A form relieving fixture as set forth in claim 2 wherein said bell crank has a variable pivot point for changing the amount of angular displacement of one end thereof relatively to the other end thereof.

4. A form relieving fixture as set forth in claim 2 wherein the means at each end of said bell crank comprises a roller carried by said end, said rollers having their axes of rotation arranged at right angles to each other.

5. A form relieving fixture as set forth in claim 2 wherein the means at each end of said bell crank comprises a slidable plunger mounted independently of said bell crank but in engagement therewith.

6. A form relieving fixture as set forth in claim 1 wherein said actuating means is adjustable relatively to said base to vary the stroke of the reciprocating motion of said workpiece supporting means.

7. A form relieving fixture comprising rotatable workpiece supporting means, a base, mounting means mounting said supporting means on said base for reciprocating motion relatively thereto, said mounting means including a pair of slideways mounted on said base, a carriage having a pair of slides disposed in said slideways connected to said supporting means, said slideways and said carriage being variable as a unit relatively to said base and said supporting means for changing the direction of said reciprocating motion of said supporting means, actuating means interposed between said supporting means and said base operable in response to rotation of said supporting means to cause said reciprocating motion of said supporting means, and means for rotating said supporting means.

8. A form relieving fixture comprising a base, a slide disc rotatably secured to said base, a carriage slidably supported on said slide disc, a workpiece supporting head supported by said carriage, said workpiece supporting head and said carriage being slidable as a unit with respect to said slide disc and said base, the positions of said slide disc and said carriage being variable relatively to said base and said head to change the direction of sliding motion of said head and said carriage; said head being rotatable in a plane normal to said sliding motion angular adjustment; a cam having a lobed side and a flat side carried by said head and adapted to rotate therewith; a bell crank on said base riding against both sides of said cam so as to universally impart motion direction and amplitude in parallel with the angular adjustment of said sliding motion.

9. A form relieving fixture comprising a base, a pair of slides supported on said base and having a pair of slide bars slidably carried in said slides, a carriage fixed to said slide bars and slidable therewith, a workpiece supporting head having a spindle therein carried by said carriage for rotatably supporting a workpiece, said head being slidable with said carriage, said spindle being provided with means for causing rotation thereof, said spindle carrying a cam axially positioned on said spindle and rotatable therewith, an arm supported on said base, said arm carrying a bell crank at a position where one end of said crank is contactable by a peripheral edge of said cam, the other end of said crank being contactable with a face of said cam, rotation of said cam causing rocking of said bell crank initiated by the peripheral edge of said cam camming said one end of said bell crank, the rocking of said bell crank causing said other end thereof to contact said cam and exert a force thereagainst whereby 'said head and said carriage are forced to move in said slide, and means to restore said head and said carriage to their original positions; one end of said said bell crank reacting against the other said bell crank via said cam as channeled and restricted by the angular position of said slides to move said head.

10. A form relieving fixture comprising a base, a slide disc rotatably mounted on said base, a pair of slides supported on said disc and having a pair of slide bars slidably carried in said slides, a carriage fixed to said slide bars and slidable therewith, a workpiece supporting head having a spindle therein rotatably supported by said carriage for rotatably supporting a workpiece, said head being slidable with said carriage; the position of said disc and said carriage being rotationally variable relatively to said base and said workpiece supporting head, to change the direction of sliding movement of said head, said spindle being provided with means for causing rotation thereof; said spindle carrying a cam axially positioned on said spindle and rotatable therewith, an arm supported on said base, said arm carrying a bell crank at a position where one end of said crank is contactable by a peripheral edge of said cam, the other end of said crank being contactable with a face of said cam, rotation of said cam causing rocking of said bell crank initiated by the peripheral edge of said cam cumming said one end of sm'd bell crank, the rocking of said bell crank causing said other end thereof to contact said cam and exert a force thereagainst whereby said head and said carriage are forced to move in said slide, and means to restore said head and said carriage to their original positions; one end of said bell crank reacting against the other said end of said bell crank via said cam to move said head as channeled and restricted by the angular position of said slides.

11. The combination of an universally adjustable form relieving fixture with self-compensating and adjusting relief motion activating means comprising a base plate, a slidedisc rotatably adjustably disposed about a vertical axis on said base plate, a carriage slidably disposed on said slidedisc along a line as adjusted in a horizontal plane, a head rotatably adjustably disposed about a vertical axis on said carriage and adapted to slide with said carriage, a workpiece support mounted on said head revolvable about a horizontal axis, a cam on said support and adapted to revolve therewith; said cam having a lobed surface and a fiat surface normal thereto; said disc and said carriage being rotationally adjustable about a vertical axis relative to said base and support to change the direction of sliding movement of said head relative to said base plate;

an arm extending from said base relative to said cam, a, bell crank on said arm having one end contacting said cam lobed surface and the other end contacting said cam flat surface; said bell crank algebraically convertingrnotion imparted by said cam along the angularly adjusted horizontal slide-line of said carriage.

12. A form relieving fixture comprising rotatable workpiece supporting means, means for rotating said workpiece supporting means, a base, said workpiece support-' ing means having mounting means mounting said workpiece supporting means for reciprocating movement relatively to said base, and means for causing reciprocating movement of said workpiece supporting means, said mounting means being variable relatively to said base and to said workpiece supporting means for changing the direction of reciprocating movement of said workpiece supporting means; said means for causing reciprocating movement of said workpiece supporting means including an element positioned between said workpiece supporting means and said base and operable in response to rotation of said workpiece supporting means to reciprocate said workpiece supporting means.

13. A fixture as set forth in claim 12 wherein said element comprises a rockable bell crank.

14. A fixture as set forth in claim 13 wherein said rockable bell crank is adjustably mounted relatively to said base and to said workpiece supporting means to vary the amplitude of reciprocating motion of said workpiece supporting means.

15. A form relieving fixture comprising angularly movable workpiece supporting means, a base, said workpiece supporting means having mounting means mounting said workpiece supporting means for reciprocating movement relatively to said base; said mounting means being angularly variable relatively to said base and to said workpiece supporting means about an axis normal to said workpiece support means angular movement for changihg the direction of reciprocating movement of said Workpiece supporting means, means for causing angular movement of said workpiece supporting means and reciprocating movement of said mounting means in conjunction with one another, and an element positioned on said base cooperating with said workpiece supporting means adapted to coordinate angular movement of said workpiece supporting means with reciprocating movement of said mounting means to pass a workpiece relative to a tool in a desired path.

References Cited in the file of this patent UNITED STATES PATENTS 614,247 Goodhew et al Nov. 15, 1898 2,413,436 Dawson Dec. 31, 1946 2,414,182 Wessman Jan. 14, 1947 2,442,318 Weisel May 25, 1948' 2,471,539 Parker May 31, 1949 2,482,802 Sanders Sept. 27, 1949 2,538,651 Parker Ian. 16, 1951 2,584,483 McDonald et a1. Feb. 5, 1952 FOREIGN PATENTS 26,452 Great Britain Nov. 11, 1925 288,624 Germany May 27, 1914'