US2364804A - Grinder - Google Patents

Description

Dem 2, 944- D. H.-MONTGOMERY ETAL 2,364,304

GRINDER Filed Oct. 10, 1941 14 Sheets-Sheet l INVENTORS fDQ/VALD H. MONTGOMERY LOU/5 R. KIRK BY 5 Z ATTORNEYS.

Dec- 12, 1944- D. H. MONTGOMERY ETAL 2,364,804

GRINDER Filed Oct. 10, 1941 14 Sheets-Sheet 2 NHL 5 O INVENTORS DONALD H. MONTfiOME'EY Lou s RK/EK ATTORNEYS Dec. 12, 1944. D. H. MONTGOMERY EI'AL 2,364,304

GRINDER Filed Oct. 10, 1941 14 Sheets-Sheet 4 INVENTORS DONALD H. MONTGOMERY 100/5 R. KIRK ATTORNEYS D 1944- D. H. MONTGOMERY ETAL 51 8 GRINDER I Filed Oct. 10. 1941 14 Sheet-Sheet 5 INVENTORS DONALD H. MmvraoMmY wu/s R. KIRK ATTORNEYS Dec. 12,1944. D. H. MONTGOMERY EI'AL 2,364,804

GRINDER Filed Oct. 10. 1941 14 Sheet-Sheet e Z44 225 O o ZZZ ZZZ J? INVENTORS. 00mm H. MONTGOMERY LOU/3 e. KIRK ATTORNEYS 1944- D. H. MONTGOMERY ETAL 2,364,804

GRINDER Filed 001:. 10, 194}. 14 Sheets-Sheet 8 lllll INVENTORS DONALD H. MONTGDMERY 100/5 9. KIRK ATTORNEYS Dec. 12, 1944.

D. H. MONTGOMERY EIAL GRINDER Filed Oct. 10, 1941 INVENTORS DONALD H. MONTGOMERY zou/s 2102 ATTORNES D- 1944. D. H. MONTGOMERY EIAL 2 3 30 GRINDER Filed Oct. 10, 1941 14 Sheets-Sheet 10 INVENTORS DONALD H. MONTGOMERY LOU/S R. KIRK ATTORNEYS Dec. 12, 1944.

D. H. MONTGOMERY El AL Filed Oct. 10, 1941 GRINDER 14 Sheets-Sheet ll Illll INVENTORS 00mm HMONTGOMERY you/s e. KIRK s I flag-MAJ A TOR EYS Dec. 12, 1944. D. H. MONTGOMERY ETAL 2,364,804

GRINDER Filed Oct. 10, 1941 14' Sheets-Sheet 13 INVENTORS oar/.410 H. MflA/TGOMEEY Lou/s 1e. K/EK BY Z ATTORNEYS:

' um'rsosrsrss PATENT ounce lneisllirk.

New

Donald 1!. Montgomery, West Hartford. and

Bristol. assigners toll'lle Calm Iaehine 00mm. New Britain,-

(learns corporation or eemum Application October 10, m Serial No. 414,204

feed in a grinding machine in accordancewith the size of a previously ground piece.

It is another object to provide improved meansfor gaugin a ground work piece and automatically the number of grinding passes or the m'atically controlling a grinding-machine in accordance with a gauging determination.

It is still another object to provide improved gauging means in connection with a grinding machine.

It is another object to provide improved means. a

for automatically compensating for wear of the abrasive element in a grinding machine.

It is another object to provide improved means for serially grinding workpieces and auto--v matically locating the abrasive surface of the grinding element and the work in proper relative position for each piece to be ground.

It is another object to provide improved dress ing means for the abrasive element in a grinding machine.

Another object is to provide a grinding machine for serially grinding work pieces with means for signalling or automatically stopping the machine when a ground work piece is not within the predetermined tolerance limits.

Other objects and various features of novelty and improvement will be hereinafter. set forth or will become apparent to those skilled in the art.

Briefly stated, in a preferred form of the inventlon we provide grinding means, such as a grinding wheel, with means for automatically traversing the work piece and grinding wheel relatively to each other. The grinding may be either external, internal, or formed wheel.

Preferably the work pieces to be ground are held on an indexible' turret providing a grinding station and gauging station. For convenience a loading station is also preferably provided; and, if desired, the grinding operation may be accomplished at more than one station. In other words. in a preferred form of machine we employ an indexible turret having chucks for holding the work pieces, and the various chucks are preferably serially indexed from the loading station to one or more grinding stations and a gauging station. The grinding is accomplishedby traversing the work piece and the abrasive element relatively to each other, and the number of grinding passes orthe amount of the feed is automatically regulated from the gauging station to grind the workpieces to the desired also. The extent of the grinding operation is determined either by determining the number of grinding passes or the feed in accordance with-a gauging determination. Such a determination is preferably made on the next previously ground piece so' that any'error in grinding of a piece will be automatically compensated for in grinding the next piece. In order to provide for very accurate grinding we prefer 'to dress the grinding wheel before or after, or both before and after, each complete grinding operation. For all normal operations the amount of abrasive removed during grinding may be disregarded and wear may be compensated for by dressing off a certain amount of the. wheel for each grinding operation or for a certain number of grinding operations.

It will usually be simpler to regulate the dimensions of the work piece within the required tolerances by controlling the number of passes of the grinding wheel, and the gausingoperation not only serves as a check on the ground dimension of the piece being gauged but automatically controls the number of grindingpasses of the piece being ground while the last previously ground piece is being gauged. when a ground piece is beyond the limits of tolerance, the

' machine is preferably stopped or a signal is given,

or the machine may be' stopp d and a given. v A preferred embodiment of our invention will be hereinafter more fully described.

In the drawings which show, for illustrative purposes only, a preferred form of the inventionan embodiment of the invention;

Fig.2 is a sectional view taken substantially in the planeofthe line 2-4 of Pig. 1;

1'18. 3 is a central sectional view taken substan- 'tially'inthe planeofthe lineHofl'ig. 1;

view taken substantially in the planes of the line I Fig. 1 is a plan view of a machine illustrating H of 1 and illustrating particularly chucking and gauging means; V

Fig. 7 is a fragmentary.,enlarged detail view of the grinding head reciprocating mechanism;

Fig. 8 is a plan view of the parts shown in Fig. 7, rparts being shown in section for purposes of illustration;

Fig.-9 is a fragmentary side view, of .a illustrating means for adjusting the chuck for alignment;

Fig. 10 is a fragmentary view in right-hand elevation of parts shown in Fig. 9;

Fig. 11 is a fragmentary, horizontal, sectional view, illustrating parts of the chuck operation mechanism;

Fig. 12 is a sectional view taken substantially in the plane of the line l2-l2 of Fig. 11 and showing the chuck operating parts in a chuck open position, as distinguished from the chuck closed position shown in Fig. 6;

Fig. 13 is a fragmentary, horizontal, sectional view through a part of the turret, illustrating an index pin and adjusting and holding means therefor;

Fig. 14 is an enlarged sectional view taken substantially in the plane of the line "-44 of Fig. 13; v

Fig. 15 is an enlarged, vertical, sectional view through a part of the grinding head, illustrating a part of the feed mechanism:

Fig. 16 is a top view in partial section of feed mechanism shown partially in Fig. 15;

Fig. 1'7 is a sectional view taken substantially in the planes of the line l'|--l1 of Fig. 15;

Fig. 18 is a sectional view taken substantially in the plane of the line, l8--i8 of Fig. 16 and illustrating the spindle driving motor and associated parts;

Fig. 19 is a' front elevation of counter mechanism mounted in the front lower base portion, as shown in Fig. 5, and illustrating counter and various control mechanisms forthe reciprocating grinder head;

Fig. 20 is a view in right-hand elevation of parts shown in Fig. 19, parts being broken away;

Fig. 21 is a fragmentary sectional view taken substantially in the plane of the line 2I-2l 'of Fig. 19;

' Fig. 22 is a fragmentary sectional view taken substantially in the plane of the line 22-22 of Fig. 19;

Fig. 23 is a fragmentary sectional view taken substantially in the plane of the line 23-23 of Fig. 19;

Fig. 24 is an enlarged view in partial section of wheel dresser mechanism, the section being taken more or less in the plane of the line 3-3 of Fig. 1;

Fig. 25 is a fragmentary view in elevation of a grinding wheel and driving motor showing the relative location between the grinding wheel, the wheel dresser and the work;

Fig. 26 shows schematically various pneumatic or fluid pressure control circuits for the machine;

Fig. 27 is a developed cam layout indicating operative steps; and

Fig. 28 shows schematically various electric closed an indexibl turret having four work stations, one station constituting a loading station;

the next station a rough grinding station; a third station a finish grinding station, and a fourth, station a gauging station. A work piece which,

Til

2,864,804 v a in the present instance, is, say, a bearing ring to be bore-ground, is mounted in a chuck at the loading station. It is then indexed to the rough grinding station where it is rough ground, then to the finish grinding station where it is finish ground, and then to the gauging station where it is gauged for size. Thefinished piece after gauging may be discharged at or before reaching the loading station. In' connection with the grinding operations, the wheels are dressed pref erably both before and after grinding each piece, and the machine is so arranged that the cutting surface of the grinding wheel always starts its feed at a definite position. The arrangement is such that the gauging apparatus gauging the work piece after it has been ground may affect the extentto which the work \piece in one of the.

finished piece being gauged is over size, the

grinding apparatus, while grinding a work piece, is caused to make fewer passes of th grinding wheel or wheels or to feed less, or both, so that the piece being ground, when it reaches the loading station, tends to be ground to the proper size. If th piece being gauged is beyond the tolerance limits the machine may be stopped or a signal given, or both.

The machine illustrated embodies a base 5 to support .the' working parts. The base more or less centrally thereof may carry a grinding head 1, which in turn carries the abrasive wheel or wheels, feed mechanism and associated parts. The base also supports-a dresser head or assembly 8. The turret 9, which bears the chucks (in this case four), is mounted for indexing about the upstanding column 6. The grinding head is reciprocated by mechanism designated generally ill (Figs. 3, 7, 8), carried within the base or frame member 5, and if desired the head I may be resiliently mounted so as to be urged upwardly and thus relieve the reciprocating mechanism of some strains. Means, such as a counter mechanism ll, shown particularly in Figs. 5 and 19, is also carried in the base 5 and serves to determine the amount of grinding, for example, by

limiting or in effect counting the number of grinding passes, or the feed, or both. The timing and coordination of the various functions of the machine are controlled by various cams carried by a main cam shaft I2 (Figs. 2, 5) in the base of the machine. It may be here noted that during the grinding operation, that is, while the grinding head is reciprocating, the cam shaft,

in the form illustrated, is unclutched from its drive and remains stationary. During the idle time the cam shaft is clutched to its drive, and the various parts actuated by the cam shaft perform their functions.

Turret and chucks The turret 8 in the form shown comprises a top disk l3 (Figs. 3, 6) integral with a cylindrical skirt I4 surrounding the column 8. A bearing sleeve or bushing I5 is secured within the skirt and has a conical inner bearing surface to fit the conical outer bearing surface It on the colunm 6. Thus, if wear takes place between the turret and the bearing column,-the conical bearing surfaces remain tight and the turret will remain concentric with the central column. Taper pin means It (Fig. 6) may hold the turret down on its column hearing, as will be clear. The turret is indexed and locked in indexed position by means which will be later described.

The turret carries chucks :(in this instance tour), and there are am i'our indexed end thereof.

polltions oi the turret. As shown more in detail in Fig. 6. each or the chucks embodies asleevelike base H which extends through an oversise opening II in the turret diskfll. The sleeve-like base is itself mounted uponi'a plate I! which is adjustably secured to the turret disk as by means or cap screws 20. For fine adjustments or the base plate It on the'turret disk, we may employ a screw 2| (Fig. 9) threaded into the turret disk and having a fiange I! thereon engageable in a. slot or notch 23 in the disk plste- I. By turn-. ing the screw II, the base plate I! may be very accurately adjusted in a direction radially oi the turret so as accurately 'to position the work held by the chuck. It may be here stated that the grinding wheel is led in a direction preferably,

generally radially inwardly of the turret so that accurate radial adjustment of the chucks on the turret is possible where grinding accuracy is required. The sleeve-like base I1 for the chuck is mounted on the base plate is and is held thereon by screws 24-24. The chuck base i1 is preferably rockably mounted on the plate it as by providing a rocker I on the under-face of the parallel to the axis of the reciprocating head.

The sides of the chuck base I! may be slabbed oil as shown in Figs. 9 and 10 to permit considerable rocking adjustment.

The sleeve-like base i! for the chuck constitutes ahousing for a pair oi anti-friction bearings 28, which may be preloaded and the inner rings 01' which carry the chuck spindle 21. At the upper end of the chuck spindle there is a chuck head 28, in which a plurality or chuck flange ring "secured to the lowerend oi the jaws are carried. In the form shown, the chuck Jaws are cylindrical iaw members 29 slidably mounted in converging bores in the chuck head 28, and each of thejaws is provided with an adjustable work-engaging screw 30. The jaws are actuated by the chuckeiaw-actuator 3 I, which is preferably spring-actuated in one direction and cam-actuated in the other. When the actuator Si is moved upwardly, thechuck jaws are separated for removal or placing or the work piece, such as a bearing ring 32; and, when the actuator II is moved downwardly, the inclination of the jaws it causes the work-engaging screws 3| securely to engage the work piece 32 and hold it during the grinding and gauging operations.

The chuck actuator II forms part of a chucking rod, which has an-aiflustable head I! on the lower Resilient means, such as the spring washers 34, are interposed between the adjustable head 33 and the lower end of the chuck spindle 21, "so that the chuckactuator II is always urged in chuck-closing direction.

The chuck actuator is moved against the springs 34 to open the chucks by means preferably acting upon an indexing movement of the turret. Such means is more clearly disclosed in Figs. 6 and 12. In the form illu'strated,a yoke 35 surrounds the lower end of the chuck spindle '21 and has an inturned fiangeengageable with-a there are but our chucking stations, the gears chuck spindle ll. Theyokeisheld asainstrotation relatively to the turret as by means or a hook member 81, bent overs pin It extendingbetween ears on the turret skirt i4. as will be understood. The yoke, I is provided with a camiollower roll it. A similar roll ll is carried by a lever ll pivoted at I! to'the yoke ll. Means, such as 'a light sprihg ll, keeps the rolls lO-ll separated as shown in Fig. 6. The lever I has a nose thereon engageable with the lower end of the chuck actuator rod,. so that, when the lever 4| is rocked in aclockwise direction (Fig. 0), the chuck actuator rod and actuator 3| will be moved upwardly against the springs 34 and the chuck opened. I

As has been heretofore stated. the chuck preterably is opened upon an indexing. movement oi the turret. In the form shown, some fixed part such as the base I carries a generally arcuate form oi cam 45 (Fig. 11) positioned so as to extend between the rolls "-40 when the turret is 39-40 pass beyond the cam 45, it will be clear that the springs 34 will serve to close the chuck on the work piece which will have been inserted while the chuck is open at the loading station. All of the chucks maybe duplicates of each other and all may be mounted so as to be accurately adjusted so that duplicate grinding maybe performed in each chuck.

The chucks are driven by suitable means, and preferably the chuck in loading station is disengaged from its drive so as to, facilitate loading and unloading. In the form shown, the chucks are belt driven, and each chuck when approaching loading station permits its drive pulley to leave the driving connection with the belt As shown particularly in Figs. 3, 4, and 6, each chuck spindle 21 carries a drive pulley 46, which may be secured to the spindle, as by means of a key 41. Each pulley may have a V-slot 4| thereon for receiving a v-belt 49, which extends about all of the chuck pulleys except that of the chuck in loading. station. The belt may be driven by a drive pulley on the driving shaft I, geared to the main drive shaft to be later described. It will be clear, then, that upon rotation of the drive shaft 5 l the chucks in grinding and gauging station will be rotated and the chuck in loading station will be stationary. or course, ii desired, the drive belt 48 may be trained over idlers so as to be released from the drive pulley in gauging station, as well as in loading station; but, generally speaking, it will be desirable to maintain the work piece in gauging station in rotation.

The turret is indexed by more or less conventional means. As shown particularly in Figs. 3, 4, and 5, the turret skirt carries-a gear 52, which through idler gears 83 is driven by a gear I carried by and rotatable with a five-slot Geneva disk IS. .The roll arm I6 0! the Geneva is driven' through one-to-one ratio spiral gears I1, one of which is driven by the cam shaft, a will be understood. Since the Geneva has five slots and II-"+44 are proportioned as to size so'that one chuck but one station.

The turret is locked in indexed positions, and

we have provided mean ior accurately relating the various locking pins to the turret locking lever. As shown particularly in Figs. 3, 13, and 14, the turret-locking disk 66 carried by the turret skirt II has four locking pins thereon corre-v Each locking pin ing pin, as will be understood. The lower or effective locking portion 63 of the locking pin 69 is slightly eccentric to the main body of the pin 69 so that upon rotation of the pin 69 in its bore, the position of the axis of the eccentric or effective locking portion 63 may be moved in a direction circumferentially of the turret. The pin 69, and consequently the effective portion 63 thereof, after adjustment, is securely clamped to the locking disk 58 by suitable means. In the form shown, the disk is slotted through the bore, as indicated at 66 in Fig. 13, and is further slotted at 65 so as to provide a tongue 66 which will give more or less. A tapered screw plug 6'! screws into a tapped opening intersecting the slot 66 so that when the taper plug 61 is screwed up, the tongue 66 will be forced over and the locking pin 69 will be rigidly held in the locking disk, as will be understood.

The locking pins 63 are engaged by a locking lever to hold the turret in indexed positions, as will be clear from Fig. 5. As there shown, the locking arm 68 rocks about the shaft 69, and. another arm 16 carrying a cam-follower roll II rocks about the same shaft. There is an arm forming part of, or movable with, the arm 16 which carries a pin 12 engageable with an ear 13 on the locking lever 66. The pin 12 is also engageable with a spring 14 opposed to the ear 16. Thus, when the cam arm 16 is rocked in a clockwise direction as viewed in Fig. 5; the pin 12 engaging with the ear 13 will rock the looking lever 69 in a clockwise direction positively and thus release the pin 63 so that the turret may be indexed. When the next pin 63 reaches substantially the position shown in Fig. 5, the cam arm I6 will be rocked in a counterclockwise direction, and the pin 12 will engage the end of the spring 74 carried by the locking lever; whereupon the latter will then be resiliently urged in a counterclockwise direction so as to cause the slot 15 thereon to embrace the sides of the locking pin 63 and thus lock the turret in indexed position. It will be noted that the side 16 of the slot 16 extends in a direction substantially radially of the turret, and the opposite side 11 of the slot acts as a camming surface so that the locking pin 63 is very accurately located by the surface I6 and is cammed into engagement with that surface by the locking surface 'II. Needless to say, the cam for actuating the looking lever is so formed and positioned as to withdraw the locking lever just prior to indexing and to move the latter in the engaging direction at just about the end of the indexing motion of the turret.

Grinding head As hasbeen stated, the grinding head 1 carries the grinding wheel or wheels and the feed mechanism, and the entire head in the preferred form is reciprocated during the grinding operation. The grinding head"! is mounted for reciprocation on the column 6 which is rigidly mounted in the frame 6. In the form shown asoasoc (Figs. 3, 12, 15) there is a flange or step-bearing 16 to support the column vertically, and the. lowerend of the column fits into a bore in theframe to be held against rotation therein as by means of a key I9. Means, such as a plate". may be secured to the lower end of the column so as to hold it rigidly in the frame.

As illustrated, the grinding head 1 maybe said to include a main base plate 9| which carries the grinding wheel or wheels and the feed mechanism. A cover serves to enhouse the feed mechanism so as to protect the same from dust, coolant, or mechanical injury. The reciprocating head has a cylindrical sleeve 92 depending from. the base plate 9| and surrounding the upper end of the column. The sleeve 62 has a bearing bushing 63 therein, fitting the outside of the column and slidable thereon. The grinding head is prevented from rotating, as by means of one or more tapered guide pins or keys 66, secured to the sleeve 92 and extending into a V-slot 86 in the column. The lower end of the slot is preferably closed by a plug 66 to prevent the entry of foreign matter into the bearing between the bushing 83 and the column. The sliding bearing surface between the bushing 63 and the column may be lubricated by a lubricant introduced through the opening 91 and into an annular space 66, from which it may pass through openings to the sliding surfaces.

The grinding head in the present instance carries two grinding wheels, which may be driven by any suitable type of motor; and, in the present instance, we have disclosed direct-driving motors in the form of air turbines. As. illustrated (Figs. 2, 16, 18), the main base plate 8| and the bearing sleeve 62 have ears or bearing projections 39-69 for supporting the grinding wheel motors. Each motor casing 96 has a hinge projection 9| fitting between the ears 69-99, and binge pintle means 92 extends through the hinge projection 9| and into the ears. The pintle means 92 may have opposed cone bearings 99-96 in the ears 69 so that the motor casing and consequently the grinding wheel will always be held in line'with the axis of the hinge pintle regardless of slight wear. The hinge pintle is preferably rigidly carried by the hinge projection 9| of the motor casing, and the hinge pintle means 92 extends upwardly for connection with the feed mechanism, as will be later described.

The grinding spindle 96 carrying the grinding wheel 96 at the lower end is mounted in the motor casing 96 preferably on ball bearings 96. which may be preloaded to give great stability to the spindle in all directions. At the upper end of the grinding spindle 96, there is a turbine rotor having blade 91 opposed to the nozzles 69 in the top plate 99 in the turbine casing. Motive fluid, such as compressed air, is

introduced to the air motor through a hose connection I66. The entering air preferably carries lubricant in the form of an oil mist for the ball bearings 96. The air and entrained lubricant, after passing the rotor blades 91, may pass down through the upper bearing 96 and in order to assure lubrication of the lower bearing 96, there may be a bypass l6l so that some of the air discharging from the turbine will not pass through the upper bearing but will pass around it and to the lower bearing. In the preferred form, the exhaust air from the turbine is directed in such fashion as to form an air shield about the grinding wheel and thus tend to prevent splashing swarms..- 'rnuarammm,m lower closure plateoi the motor-"casing is provided with generally outwardly and downwardly,

directed sxhaustnoasies Ill so that the escaping airin eiiectwillformaconecurtainextending downwardly around the grinding wheel and-thus act as a shield for thecoolant. etc.

The air motor may be run at exceedingly high speeds, which high speeds are desirable when very small pieces are being a o d internally, andconsequently when very small grinding wheels must be However, it is to be un-' derstood that the grinding wheels may be other- Reciprocating mechanism The grinding wheel or wheels and the work are traversed relatively to each other in this case by reciprocsting the grindinghead sons to cause the grinding wheels to make the desired number of grinding passes. The reciprocating motion is derived from the main drive, which may be of any desired type. In the form showniFigs. 1, 2, 4, i) the'main drive pulley I" carried by the main drive shaft I is driven by a belt from any suitable driving motor. ,The shalt I carries a worm IOI, driving a wormwheel I, which is freely rotatable on the shaft-II. The worm wheel I has a clutch face III. to be engaged by a driven clutch face Illlon the main clutch eccentric strap IIS. Needle bearings or other anti-friction bearing members may be interposed between the eccentric and its strap, if desired.

v The eccentric strap II! is pivotallysecured by means of a stub shaft II! to a reciprocating lever Ill. The reciprocating lever is fixedly seured to ashaft H8, which shaft fixedly carries an arm H9, so that the lever Ill and arm III, both being keyed to the shaft III, constitute in efl'ect one single lever. 'A part of the frame 8- has a link I2. pivotally mounted thereon by means of a shaft or pin III. This shaft Ill is mounted in spaced-apart bearings in the frame; and the link III, mounted on the shaft, is guided between the spaced-apart frame portions, as will be clear from Fig. 8. The link I! has a bearing on the shaft H8 and the latter shaft is freely rotatable in that hearing. The link III is so arranged that it may be releasably secured to the frame 6 and in eilfect become temporarily an The purposes! the its pivotlh lt Ill. and the through the arcuate slot, as

reciprocate the grinding head when is "in', or raised as viewed in rendering the eccentric reciprocating mechanism ineffective when the locking pin is "out."

As illustrated (Figs. 3.5. v7. 8) the lever II! is pivotally secured to a connecting rod orlink in, secured to a crosshead m (Pig. 3), which crosshead carriesan actuating rod m, secured to the main base II of the reciprocating grinding head]. In the preferred form the main column has an" abutment plate III therein, acting as a seat for a coiled compression spring I30, which acts beneath the reciprocating head soas resiliently to support and raise the grindinghead when the latter is freed from the reciprocating linkage.

In order to adjust the stroke of the grinding headthe pivotal connection between the lever III and the connecting link III is adjustable.

"In the form shown the lever- I II has a longitudinally extending T-slot III for receiving a'securmg bolt I32. diustable in the slot and carrying a bearing member I" to which the'rod III is secured. Thus, when it is desired to change the stroke, the bolt in the T-slot is released by back ing off on the securing nut Ill, after which the bolt Ill may be moved to the desired position in the slot and thus change the effective length of the lever- 9. After the desired point of adjustment has been reachedthe securing nut Illis,

integral part thereof, so that the eccentric may rock the lever Ill-4 I9 freely about the temporarily fixed bearing for the pivot shaft ,I ll. In the form shown the frame slidably carries a looking pin I22, having a taper head I23 at the free end. The link I has a taper seat I to receive the head I28, so as'to securely lock the link Ill to the locking pin seated in the seatv I. The link I2. is also provided with an arcuate slot I25 intersecting the seat Ill, as clearly shown in F'ig. "I. When the reciprocable locking pin I22 end of the connecting rod I26 without moving the reciprocating head. When the tapered head of course, turned up to maintain the adjustment. The operation of the reciprocating mechanism is as follows:

When the tapered locking pin I23 is seated in the seat I24 of the link I20, the latter in effect becomes a part of the frame, and the eccentric ill will serve to rock the lever II'I-II! about the now ilxed pivot axis of shaft II8 to reciprocate the grinding head. It will be seen that the compression spring I" relieves the reciprocating mechanism of considerable strain and facilitates reciprocation. After the grinding operation has been completed, the reciprocating linkage is renderedineilective, and the grinding head is.raised by the spring I" to its uppermost or retracted position. The ineffective linkage results from dropping the tapered head I23 out of its seat I into the position shown in Fig. 8. When the taper-head pinis thus positioned, the link Ill is no longer coupled to the frame and is, of course, free to oscillate about the pivot shaft I2I, this ascillation being permitted, as heretofore indicated, by the arcuate slot I25. When the pin head I23 is withdrawn, the grinding head will move to its uppermost position and thereforecarry the free end of the lever III to its highest position. The eccentric, acting on the right-hand end of the lever I II, will therefore raise and lower that end; and, since the left-hand end of the lever I Is is, in effect, fixed at its highest position, theilever III will carry the pin Ill and with it the left-hand end of the link lit up and downthus simply permitting the lever III-I Is to rock freely about the axis of the bearing I33 at the m is again seated in the seat 124, the 1m: m is once more locked to the frame, thus making the shaft I II a stationary pivot axis for the lever is moved out, that is, downwardly as viewed Fig. 8, so as to'disengagc the head I23 from the seat I24. the link I" may be freely rocked about rs II'I-I Is to permit reciprocation of the grinding head again. 4

The locking pin I2: is automatically actuated opposite end is pivoted at I38 to a link I38, which is itself pivoted at I40 to an actuating piston, the

,purpose and function of which will be later described. The lever I38 is also pivoted at the point I38 to a link I, which carries a pair of abutment heads I42I43 to act as abutments for springs I44 on opposite sides of a sliding head on-the bell crank lever I46, which is pivoted to the frame at I46. The free end of .the bellcrank lever I45 comprises a fork I41 for shifting the clutch sleeve I08, heretofore mentioned.

Thus, during the grinding operation, the grinding head, carrying one or more grinding wheels,

is reciprocated so as to effect the requisite number of grinding passes. When the grinding operation has been completed, the tapered locking pin I28 is withdrawn from its seat so as to release the reciprocating linkage, and the grinding head moves to its upper position under the influence of the coil spring I30. In order to prevent the grinding head from springing up too rapidly and also to lower the grinding head to such a position that the tapered locking pin I23 may be reengaged with its seat I24 for the next grinding cycle, we provide retarding and actuating means such as cam means. In the form shown (Figs. 3, 5), there is a link I48 pivotally secured at one end to the cross-head I21 and at the opposite end to a lever I48 pivoted to the frame at, I 50. The lever carries a cam roll III to engage a face cam I52 on the cam drum carried by the main-cam shaft I2. The cam drum, it will be recalled, is stationary during the grinding operation, and the cam I52 will be positioned angularly of the cam shaft so that the cam roll I5l will engage the cam I52 when the grinding head has moved to a position just slightly higher than its uppermost grinding pbsition, and also so that, when.

the cam shaft is rotated, the upward movement of the grinding head under the influence of the spring I30 will be retarded. Just prior to the next grinding operation, the cam I52 will slowly lower the grinding head to such an extent that the tapered locking pin I23 may readily find its seat I24. A further purpose of retarding the upward speed of the grinding head between grinding operations and'of lowering the grinding head at a definite relatively slow rate, is to permit wheel dressers, to be later described, to act on the grinding wheels for dressing the same.

Feed

During the reciprocation of the grinding head .thegrinding wheel or wheels and the work will beadvanced or fed relatively to each other. The feed mechanism in the form shown feeds the wheels, is carried by the grinding head, and is actuated upon the reciprocation of the grinding head by the cam-rocker means or the like. As has been heretofore stated the grinding wheels are mounted for swinging about theaxis of the pintle 82 (Figs. 2, 16). A feed arm I53 may be secured ,to the 'pintle 82, rigid with the wheel mount, and the feeding of the grinding wheel accomplished by swinging the feed arm I53 about theaxis of the pintle 82. Both the rough and finish grinding wheels may be and preferably are .mounted'in'the same manner and fed in the same general manner. Feeding by swinging the feed arm I63 may be accomplished as follows:

The grinding head carries a ratchet wheel I54 (Figs. 15, 16) mounted upon a sleeve I05, which is in turn-mounted upon, and preferably pinned to, a bearing quill I58. The quill is preferably mounted on anti-friction bearings I51 in the frame of the reciprocating head. The quill I58 may be mounted against endwise movement by means of theangular contact bearings, the outer rings of which are shouldered to flt opposite abutment surfaces on the grind-head frame, as will be clear from Fig. 16. A nut I58, threaded onto the quill and abutting the inner ring of one bearing, serves to adjust the pre-load on the bearings and prevent endwise movement of the quill. The quill may be internally threaded, as indicated at I58, for receiving a threaded feedscrew I80. In order to take up any possible backlash in the quill and feed screw we may provide a gland I6I, threaded on the feed screw I60 and adiustably held on the quill, as by means of a cam I14 on the up-stroke. The lever I15 is pivgland nut I62. By turning up on the gland nut it will be understood that all backlash may be taken out.

The feed screw is connected to the feed arm I53 by suitable means and, in the form shown, we employ a flat plate or spring-like element I63, which slidably fits in a slot in the feed screw and which may bepinned therein by a transverse pin I64, so that the plate member I63 may move relatively to the feed screwin the direction of its flat width and may yield in a direction across the hat width, due to its inherent yieldability. The

other end of the plate connector I63 may be similarly connected to a hand-operated shaft I65, that is, by means of a vslot connection I66 and transverse pin I61. The hand-operated shaft is held against endwise movement in the arm I53, as by having a head I68 thereon abutting against a thrust washer I68 on the feed arm I53, so that outward movement, that is, movement toward the right of the feed" screw I60, will positively swing the arm I53 in a counterclockwise direction, which is the feeding direction in the case of the roughing wheel located at the right in Fig. 16. The shaft I may be rotated for grinding wheel adjustment, as .by means of a hand vwheel 10 and may be held as by means of a employed for protecting the: feed screw and adjacent parts. Since the quill I56 is held against endwise movement in the grinding head, rotation of the feed screw I60 relatively to the quill,

as by means of the hand wheel I10 or by means tracting direction, as will be understood. The

hand wheel I10 is employed for rapid rotation .of

the feed screw for adjusting the cutting wheel, as, for example, when a new wheel is put in place.

The automatic feed may be effected through. the ratchet wheel I54 by means now to be described. The column 6 may be provided with a fixed cam (Figs. 3, 15), which may be adjusted up and down on the column, as may be desired.-

" which will serve to feed the grinding wheels on the up-stroke. As illustrated, there is a lever I15 having a cam roller I16 for engagement with the cam I13 on the down-stroke and with the oted to the reciprocating grinding head at I11 and the upper end of the lever may have a roll

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