US1779779A

US1779779A - Automatic grinding machine

Info

Publication number: US1779779A
Application number: US288365A
Authority: US
Inventors: Charles H Norton
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1925-09-28
Filing date: 1928-06-26
Publication date: 1930-10-28
Anticipated expiration: 1947-10-28

Description

0ct. v28, 1930. c. H. NORTON AUTOMATIC GRINDING MACHINE Original Filed Sept. 28, 1925 5 Sheets-Sheet 1 QON NM om uom vow NN ww wnzsses 'Colwomd H. Gw'U-dravl. www

Oct. 28, 1930. c. H. NORTON AUTOMATIC GRINDING MACHINE 1925 5 Sheets-Sheet 2 Original Filed Sept. 28

Charles HNortm M um Oct. 28, 1930.

c. H. NORTON AUTOMATIC GRINDING ,MACHINE Original Filed Sept.

28, 1925 5 Sheets-Sheet 3 GW" f witnesses I Oct. 28, 1930.-V c. H. NORTON 1,779,779

AUTOMATIC GRINDING MACHINE Original Filed Sept. 28. 1925 5 Sheets-Sheet 4 27s 26s 26e 2?? 2&0 zal Charles H. Norton.

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Witnesses l edm@ www] Oct. 28, 1930. c. H. NORTON L779779 AUTOMATIC GRINDING MACHINE Original Filed'Sept. 28I 1925 5 Sheets-Sheet 5 28B l am 29o 29a qq gnventoz F 16` 19 Charles H. Nurtan Witnesses edm@ H. @www www@ Il wt EL www Patented oci. ze, 1930 PATENT OFFICE UNITED STATES CHARLES i1 NORTON, OF PLAINVILLE, CONNEOTIoUnAssIGNOB To NORTON COMPANY, or WORCESTER, MASSACHUSETTS, A CORPORATION or MASSACHUSETTS AUTOMATIC GRINDING MACHINE Uriglnal application led September 28, 1925, Serial No. 59,158, and in Great Britain September 6, 1926.

Divided and this application led June 26, 1928. Serial No. 288,365.

My invention relates to a grinding machine and more particularly to an automatic machine for grinding cylindrical objects. This applicationis a division of m copending ap- '5 plicationSerial No. 59,158 led September 28, 1925, relating to automatic cylindrical grinding machines. v v

The ordinary plain cylindrical grinding machine is too slow for rapid production ot t@ small cylindrical objects, since a large num.-

ber of operations are required of the operator While the machine remains idle. In using such a machine, when a piece of Work has been ground to size, it is necessary for the'operator i5 to stop the motion of the machine, turn the feed mechanism to remove the grinding Wheel from the Work, move the ootstoclrA center, and manually remove the piece of Work from the centers. He then takes the next-rough 2o piece of work to be ground, which has previously been dogged, and inserts it .in arial alignment between the centers. This being done, he brings the footstock center into position tosupport the Work and starts the machine in motion, after which he must feed the Wheel into the Work and occasionally stop to caliper the work and make sure of getting it to size. 'It will be readily seen that considerable time is lost, by having to perform allthese operations, and it is seldom that Work is of such a size and character that an operator can run more than one of these machines at a time. l

It is an object of my invention to overcome such diiliculties and to increase production when a large number of duplicate pieces are to be ground by'providing a ma-V chine` which may be fully or matic in operationand there little attention on the part oi the operator.

' A' desirable type of automatic grinding machine is one which is so arranged that. the Work may be placed in a hopper by the operator and from there fed into axial alignment with automatically operated gripping members which support' and rotate the Work during the grinding operation. The pieces of work should oe-ground successively by feedvai ing the grinding wheel with extreme pre-l cision through a predetermined distance and partially autoy` require but then withdrawing it for removal of the finished work and replacement by a Jfresh piece. To feed the Wheel into the work requires a mechanism which goes through a cycle of operations and which is capable of tine adj ustments and will produce uniform and duplicate results repeatedly. The operator Should be required merely to fill the magazine with rough pieces of Work to be sized, and from time to time make slight adjustments tov take care of any Wear of thegrinding wheel. v

The automatic grinding, machines hereto-y fore proposed have not been wholly satisfactory for various reasons. They have either depended' on the action of a chuck to hold and drive the work from one end and a footstock center to support the Work on the other end, or they have otherwise required a complicated mechanism to insert new pieces of Work into the machine, hold the same during grinding, and'the'reafter discharge it.

It is accordingly another object of m inventionto utilize a work supportingl an rotating mechanism in which the Work is gripped between two positively rotated spindles and supported by pressure against the ends'of the piece so as to give a frictional driving contact betWeent-he spindles and the work, and thereby to provide a simple Work supporting device which permits quick replacement of the Work and eiiicient operation otl 4the machine Without the necessity of cliucking or centeringl the Work.

It is a further Object to provide an auto matic mechanism capable-lof feeding pieces of Work successively to the Work supporting and rotating members andvvhich is operated, in timed relation with the-movement of the ,Cooperating Work support and Wheel `feed mechanism so as to insure efficient and rapid operation of the machine.

It is afurther object supporting mechanism which swill'"automati-- cally grip successive pieces of Work of dier-` ent sizes in a yielding and'cushioned manner, and particularly to so arrange this mecha nism that the l.Work supporting members may be brought into Contact With the Workby an adjustable pressure device but positively to provide a Wort;

of my invention so arranged as to operate withdrawn by a power operated mechanism, and thereby insure safety in the operation of the machine.

lA further object is to provide a fully automaticgrinding machine in which the 'work pieces are successively gripped by andreleased from work supporting members, and Y to provide mechanism co-ordinating such an operation with the wheel feeding movement, so thatthey will be carried on in a proper timed relation.

With these and other objects in view as will be apparent to one skilled in the art, my invention resides in the combination of parts set forth in the accompanying description and covered by the claims appended hereto.

I have illustrated in the drawings a machine including all of the various features automatically, but certain of these .features may be incorporated, as desired, ina semiautomatic machine intended to be manually controlled for grinding a single piece of work at a time, and it is to be understood that such subcombinations fall Within the scope of my invention. n y

Referring to the drawings in which like reference numerals indicate like parts:

Figure 1 is a front elevation of my auto; matic grinding machine having portions broken away to more clearly show the inside mechanism;

Fig. 2 is an end elevation of my machine, with portions of the base similarly broken away; i

Fig.v 3 is an enlarged fragmentary view showing the spindle operating mechanism;

vFig.` 4 is an enlarged end elevation of the parts shown in'Fig.` 3;

Fig. 5 is an enlarged fragmentary end view showmg the magazine turret mechanism for feeding the work to its grinding position;

Fig. 6 is an enlarged rear view of the magazine turret mechanism;

Fig. 7 is an enlarged fragmentary sectional view taken-approximately on the line 7-7 0f.Eig 5;

Fig. 8` is an enlarged fragmentary view taken approximately on the line 8 8 of Fig. 2 showin the cam operated feed mechanism and the indemng mechanism for the work turret; y f

Fig. 9 is an enlarged fragmentary view taken approximately on the line 9-9 of Fig. 2 showing a portion of the feed mechanism and stop;

' Fig. 10 is an enlarged detail view of the lever shown in Fig. 8 for tripping ythe ratchet Fig. 11 is an enlarged sectional detail view .taken approximately on the line 11p-11 of a Fig. 10;

ig. 12 is a fragmentary section on the line 12-12 of Fig. 2; j u O Fig. 13 isan enlarged fragmentary detail Vof work presenting mechanism; and

Fig. 18 is a fragmentary rear elevation of the mechanism shown in Fig. 17. In my preferred construction, I havey illustrated an automatic .grinding machine in which the work is placed in a hopper and is "then fed automatically into axial alignment y with a pair of rotatable Work supportin spindles, which are arranged to move toward the ends of the work to grip it adjacent its periphery for rotating it by frictional contact. In order to feedv the grinding wheel and the work relatively towards each other, one of these, and preferably the wheel, is mounted on a slide, and this slide is moved precisel cam so as to move in timed relation with the work supporting spindle mechanism. I prefer to feed the'slide forward by `an adjustable Weight and to move 'it back positively by the cam mechanism, and I so arrange the parts that the grinding wheel is fed rapidly at the start and then with a slow and uniform ing wheel frm"the work.V Likewise, the

work gripping mechanism is preferably op` erated in one direction 'to grip the work by an adjustable weight and in the opposite direction by a power driven cam.

The work may be fed to the work supports by hand'or automatically, as by means of a turret wheel which is moved in timed relation with the spindles to present the Work thereto and then remain stationary during the grinding operation. The turret may be moved positively by a oWer drive or the Weight of the work may e utilizedto rotate it, and a cam operated control device insures that the wheel remain immovable exce t when release ofthe finished work and feedin of a new piece is. required. I also pro-V v1 e nism by means of a cross feed screw f mechanism. This is operated by a power drive which is preferably controlled by a a wheel spindle reciprocating mecha;l to oscillate or reciprocate the grinding'- base 12 carries the usual grinding wheel slide 13 which is adapted to slide transversely on the usual V-way 14 and flat way 15. mating with corresponding ways on the base. The grinding wheel slide carries a grinding wheel spindle which is mounted in suitable bearings in the wheel sli-de and carries on one end a Grinding wheel 19, as clearly illustrated and described in my prior Patent No.

A pair of rotatable axially slidable work supporting spindles 20 and 21 (Figs. 1 and 3) are journaled in the front base of the machine in two pairs of

bearings

22 and 23 respectively,

which may be of suitable construction. These spindles are preferably so arranged that they may be driven in synchronism with each other so as to produce a proper rotation of the work.

Power dri/ving mechanism As shown in Fig. 2, the rear base is provided with a main drive shaft 30, driven by any suitable source of power, which carries avpulley 32 to transmit power to the wheel spindle 18 by means of a belt 33 passing over a pulley 34 on the wheel spindle 18 and an idler belt tensionin pulley 35. Power may be transmitted to t e front base of the machine from the main drive shaft 30 by a sprocket 40 thereon and a link drive chain 41 to the sprocket 42 on the shaft 43.` The sprocket 42 is rotatably mounted on the shaft 43 and is so constructed that it may be connected or disconnected from the shaft by means of a suitably constructed clutch 44 which is operated by the usual yoked member 45 pivoted to the base at 46 and the manually operable lever 47. The shaft 43 is connected by a coupling 49 to the shaft 50 which carries a spur gear 51 meshing with a spur gear 52 on the short shaft 53. The shaft 53 carries on its other end a spur gear 54 meshing with a spur gear 55 on the cross shaft 56 which extends the length of the machine. This shaft 56 carries the sprockets 60 and 61 respectively which drive the lilik chains 6 4 and 65. These in turn drive the

sprockets

66 and 67 on the work supporting spindles 20 and 21-respectively. The

chains

64 and 65 are of sufiicient length and have enough flexibility so that the s

rockets

66 and 67 may be fixed to the axial y

slidable work spindles

20 and 21.

The

gears

54 and 55 are preferably change gears andare so constructed that they. may

be readily removed and replaced by other combinations to vary the work rotating speed. These gears 54 and 55, as illustrated, are arranged to give a slow speed rotation of the work support spindles. By removing them and placing the larger gear 55 on the shaft 53 and the smaller gear 54 on the shaft 56 the speed of rotation of the work supportingsspindles may be increased.

To permit tensioning the

link drive chains

64 and 65, I preferably mount the shaft 56 in the two swinging brackets 70 and 71 (Fig.

13) which are arranged to swing about the axis of the shaft 53 as a pivot, so that for any position of the shaft 56, the

gears

54 and 55 are always in mesh. The

brackets

70 and 71 are each provided with an elongated slot 7 3 and a set screw 74 which passes through the elongated slot and is screw threaded into a portion of the base'of themachine. It

will thus be readily seen that the brackets 7 0 and 71 may be separately adjustable and locked in a desired position, so that either of the

chains

64 and 65 may be tensioned withoult disturbing the driving tension ofthe ot 1er.

O'fross feed mechanism.

One of the main features of my invention catable feeding movement of the wheel into the work. To this end, I mount one of these', and preferably the grinding wheel, on a cross slide and connect a feed screw thereto. This feed screw -is rotated automatically by a power mechanism, and the rate of rotation and direction of movement is accurately controlled by a further automatic device, which is preferably a cam, so that the wheel is fed forward a predetermined amount and then withdrawn. Successive pieces` of work may be brought to the same exact size by utilizing an adjustable stop so arranged that the feed screw may not lbe turned beyond a certain point, irrespective of the operation of the cam and power drive therefor. The power is best applied by means of an uadjustable weight arranged ,to feed the wheel into the work as permitted by the cam, and `the latter serves to withdraw the wheel and lift the weight for the next infeed operation.

A further important feature lies in a construction which permit-s one to vary the length of the feeding stroke without changing the cam. This is simply accomplished by connecting the camiwith the screw by means of a chain passing over a sprocket on the screw shaft and adjustably connected to an involute shaped lever which is oscillated by the cam. The point of connection of the chain withthe lever` may be adjusted to change the effective length ofthe lever arm, and this serves merely to wrap the chain about the sprocket without turning the screw.

While the slide may be moved by various' ploy one which is patterned generally after that shown in my prior Patents No. 762,838 and No. 1,443,924. This mechanism comprises a half-nut 80 secured to the under side of the wheel slide 13 which is screw threaded to engage a plurality of corresponding threads on a feed screw 81. The feed screw is journalled in the rear base of the machine and carries on its front end a gear 83 meshing with a pinion 84'on the shaft 85 journalled in the front base of the machine. The shaft 85 carries a gear 86 meshing with a `gear 87 on the shaft 88, on which is mounted the gear wheel 89 arranged to turn the feed screw. The hand feed lever 92 is rotatably mounted on a projection of the shaft 88 and carries a micrometer adjusting mechanism 93, such as is clearly described in my prior Patent No. 762,838? and the patent to Wilcox No. 1,261,083. Thismechanism permits adjusting the feed arm 94 relative to the gear wheel 89, and comprises a pinion 95 meshing with the gear 89 and a crank arm 96 adjustably clamped to the extension 97 of the-pinion shaft 95. By pulling the plunger 98 from thc opening 99 in the index plate 100, the crank arm 96 may be turned the desired amount to adjust the arm 94 relative to the gear Wheel 89. )Vhcn in adjusted position the plunger 98 may be -reinserted in the nearest opening 99 in the'index plate 100. This makes it possible to position the grinding wheel as desired relative to the work, to adjust for wheel wear, or even to fed the wheel by hand when considered necessary.

@am controlled power drive for feed screw tively connected to the feed screw, which is so constructed and arranged that the distance and rate of travel of thel wheel into and away from the work are predetermined in accordance with the contour shape of the cam. The embodiment illustrated comprises an ,adjustable weight connected ,to the screw by a chain and sprocket, and the movement of the weight is controlled by a power driven cam. To this end, I may mount a cam 110 on the shaft lll-which isjournalled in the front base of the machine. To positively rotate the cam 110, a worm 112 is mounted on the shaft 50 (Fig..1) in mesh with a worm gear 113 mounted on the shaft 114. The other end of the shaft 114 carries a gear 115 (Figs. 2, 3 and 4) which in turn meshes with an intermediate gear 116, arranged to drive a gear 117 on the cam shaft 111 to rotate the cam 110.

To permit varying the speed of rotation of the cam and consequently the speed at which the grinding'wheel is fed inwardly, I employ a suitable change gear mechanism. This may be simply accomplished by mounting the gear 116 on a swinging arm 120, which swings about the axis of the cam shaft 111 as a pvot.

The small gear 114 is preferably a change gear which is so constructed that it may readily be slipped into place or taken off and changed lfor a larger or smaller gear. The arm 120 is preferably a bell crank7 having a. projecting arm 121 by which the gear 116 may be swung into mesh with the change gear 115. The gear 116.is locked in its adjusted position byl a clamping screw 123, which slides within the arcuate slot 124 in the member 125. This lnember 125 is fixed inside the machine by the threaded studs 126 (Fig. 2).

To transmit the motion of the cam 110 so as to control the movement of the feed mechanism, I mount a lever 130 (Figs. 1, 8 and 12) on a pivot 131 on the base of the machine. The short arm 132 of the lever 130 carries a follower roller 133 which is adapted to engage the operative surface of the cam 110. A radially extending arm 135 having a projecting hub 136 is journalled on the shaft 88 and is provided at its outer end with al locking screw 137 adapted to lock the arm 135 to a projection of the arm 94. The member 135 carries a sprocket 138 on its projecting hub 136. To transmit the cam motion from the lever 130 to the feed mechanism, I employ a'link chain 140 Which passes over the f sprocket 138 and has one end adjustably connected to the arm 145 by a slidable clamping member 142. The lower end of the chain 140 is connected to a weight 143 which is slidably mounted in the housing or bracket 144 secured to` the base of the imachine. The weight 143 is of sufficient size to turn the feed screw to feed the grinding wheel into the work and to keep the camfollower roller 133 always in Contact with the surface of the cam 110. v

The feed cam 110 is preferably of such a shape that it will cause the grinding wheel to be fed rapidly toward the work for a short period of timuntil it is about to contact with the work, and thereafter be moved at a slow and uniform rate until the work has been reduced to its approximate size. During the final stage of grinding the feed mechanism is held immovable by a stop mechanism for a short period of time to permit the grinding wheel to finish the grinding operation.

From this disclosure, it will be readily seen that the weight 143 turns the feed screw as limited by the shape and motion of the cam 110 to produce the feeding action of the grinding wheel' toward the Work. The return motionof the grinding Wheel caused by the abrupt rise on thecam positively turns the feed screw in the opposite direction against the action of the weight 143, and moves the grinding wheel rearwardly to its initial position.

Feed stop device I To positively limit theinfeed of the grinding wheel at a predetermined point, I provide a stop screw 146 adjustably held in position by a locking nut 147 in a bracket 148 fixed to the front of the machine base (Figs. 1, 9 and 12). The bracket 148 is so shaped and positioned on the base that the screw 146 is in the path of ,the outer abutment 149 of arm 135. The stop screw 146 is preferably so adjusted that the arm 135 contacts with the screw 146 before the cam follower roller 133 reaches the end of the infeed .portion of the cam. ment, it will be readily seen that the stop screw 146 positively limits the feeding movement of the grinding wheel at a predetermined point, since the cam mechanism acts, not directly upon a massive wheel slide, but upon the feed screw, and it is possible to turn the latter with a line degree of precision and therefore feed the grinding wheel exactly to a predetermined position and reduce pieces of work to a desired size successively and uniformly. Moreover, when the stop becomes effective,the feed control cam may continue to rotate but the stop holds the cam follower out of contact with the cam until it is time to move the wheel away from the work; hence, `the stop acts 'positively to limit the infeed of the grinding wheel.

Adjustment of feeding stroke' The feeding motion of the cam is limited by the size and shape of the cam. In order that the amount of feeding movement per cycle may be varied, I preferably make the upper arm of lever 130 as an involute shaped arm 145. By shifting the position of theslidable clamping 'member 142, which is secured.. to the end of the link chain, alonfr the arm 145, I change the effective-length ofD the lever arm 145 and consequently vary the amount of feeding movement. The nearer the clamping member 142` is to the pivot point 131, the less the feeding movement. The reater the d istance away the clamping memer 142 is from pivot 131, the greater the distance through which the mechanism will feed the wheel into the work. Y V

By making the lever 145 in the shape of an involute ofa circle,- the clamp 142 may be adjusted along thelever without changing the relative position of the link cham and therefore without disturbing the position of the feed screw, since the chain merelyY wraps itself around the sprocket 138 and does not turn the screw when such adjustment is made.

In setting up the feed mechanism forany particular piece of Work to be ground, the clutch 44 is thrown out of the4 work is mounted on the work supporting spindles. The locking screw 137 is then disconnected from the projection of the feed arm 94 so that the radially extending arm 135 swings downwardly into contact with the stop screw 146.1 The feed mechanism is Vith this adj ust-` the grinding engagement and f tion is the now free so that the grinding wheel may be fed manually into the work.

The feed cam 110 is then rotated by manually turning the shaft 111 by placing 'a wrench on the projection 134 until the fol-7 lower roller 133 is a shortdistance from the abrupt rise inthe cam. The feed mechanism is then turned by means of the hand lever 92 until the grinding wheel reaches a position where the work has been reduced to its desired size. By withdrawing the micrometer adjusting plunger'and turning the pinion relative4 to the feed gear, the feed arm 94 swings into substantial alignment with the arm 135 so that the locking screw 137 may be screwed into place and lock the feed mechanism to the arm 135. It may be necessary at this point to adjust the micrometer device slightl contact with t e stop screw 146. It also may be necessary to make a slight adjustment of the stop screw 146'to be sure that the cam follower roller 133 does not touch the operative surface of the cam for a short distance before the abrupt rise is reached. If this adjustment is necessary, the operator will also `have to make a further readjustment of the micrometer device to bring the workto the desired size. j

In view of the above explanation, it will be understood that the feed screw is rotated through a definite distance and at a predetermined rate controlled by the contour shape and `rate of movement of' a cam, so-that the grinding wheel moves cyclically and repeatedly through the same path of.r advance and-retreat, or what may be termedan invariable cam cycle.- The distance through which the wheel moves 1s therefore a function of the extent of a single rise and fall of the follower on thecam, and this may be varied by making adjustments of the stop and of the location of member 142k on the arm 145. These xadjustments make it possible to regulate the rate of feed, as well as the distance of travel of the wheel, so that operation may be controlled as desired. 'It will also be`v understood that the adjustable stop makes it possible to, grind with even greater-precision of measurement than can be obtained. by theuse of the cam alone, since the stop may be set-to stop the infeed of the wheel before the cam follower yhas reached the extent of its throw, i. e. the

lowest point on the cam, and thereby prevent further infeed ofthe wheel and permit the grindin operation to die out gradually and so pro uce a ne finish on the work.

Work gripping and snpporting mechanism Another important feature of` the inven rovision of a power operated mechanism or gripping an centering the work and thereafter rotating it for the grinding operation. This may be `accomto bring. the arm 135 into upon the shape of the Y adjustable weight 170. This spindles. These spindles are work supporting plished by means of a yielding device which 1s preferably weight operated to close the gripping members on theV work, and a power operate positively acting mechanism to rclease the work, which parts move in timed relation with the wheel feed mechanism. I have found that such a work gripping and rotating device, to be effective, must engage the work close to the periphery thereof, so that the torque and the friction of the rotating members may be as high as possible, as compared with the retarding effect of the grinding'wheel on the work. If the work is gripped only near its center line, there is a serious possibility of slilpiage and consequent imperfect grinding. y device is so arranged that it automatically centers the work, and it is not necessary to first provide the work with center punch markings or to make other provisions for this purpose. The particular type of work gripper used depends work to be ground. In members which engage work. If the work is hollow, I may utilizespring fingers fitting within the work to assist-in supporting it.

In my preferred construction, shown in detail in Figs. 3 and 4, I provide a simple arrangement for moving the work gripping members which is` operated by a cam controlled weight and linkage mechanism. As shown, the

spindles

20 and 21 are axially movable and carry work gripping members at their inner ends which are forced into contact with the work and are rotated by the moved axially by

levers

150 and 151 pivoted to the

bases

152 and 153 respectively. The upper ends of these levers are each provided with yoked

portions

154 and 155 which are connected to move the spindles, which carry the work gripping members, axially towards and from the ends ofthe work. The lever 151 is shaped like a bell crank and has a downwardly extending portion 157 connected bythe pivot pin 158 to the connecting rod 159. To move the two levers simultaneously in opposite directions, I provide the lower end of the lever 150 with a gear ooth projection 162, meshing with the teeth r projections 163 on the substantially T-shaped lever 164. The lower arm of the T-shaped lever 164 is connected by the pivot pin` 165 to the connecting rod 159. rllhe long arm 168 of the T-shaped lever 164 supports through the rod` 169 an mechanism, as clearly shown in Figs. 1, 3 and 4, is such that the weight normally acts to hold the members towards each other to grip the opposite ends of with an equalized pressure.

To separate the work supporting spindles 2O and 21 and thereby release the finished work and permit a new piece to be put into position for grinding, I provide an adjustsome cases, I employ only the ends of the the work piece able, positively actuated intermittent mechanismr operating in timed relation with the wheel feeding mechanism. To this end, I provide a revoluble member arranged to strike the lower. end of one of the spindle actuating levers and force it to move the grippers outwardly. As illustrated, I employ a roller 180 carried by the adjustable arm 181 rotatably mounted on the cam shaft 111. A projecting arm 182 is mounted in fixed position on the cam shaft 111 and provided at its outer end with an adjusting screw 183 and lock nut 184. The outer end of the adjusting screw 183 bears against the projection 186 of the lever 181 so that the roller 180 carried by the arm 181 may be adjusted angularly relative to the operative 'face of the cam 110. This insures operating the work supporting spindles in timed relation with the movement of the grinding wheel slide. Depending from the pivot- 158 on the bell crank 157 is an adjustable arm 187 carrying a pin or projection 188 so constructed and positioned that it is in the path of the roller 180. As the cam shaft 111 rotates, the adjusting screw 183 carries the roller arm 181 and the roller 180 about its axis. The roller 180 contacts with the pin or projection 188 and swings the linkage mechanism towards the left, thus moving the

arms

150 and 151 outwardly to separate the work ipping members on the supporting s ind es. This construction provides means or yieldingly moving the spindles towards each other, so as to make the machine safe in its operation, and insures a positive separation of the spindles when the work has been finished.

Adjustments for work supports To vary the amount of movement of the work supporting spindles, I preferably mount the arm 187 so that it pivots about the pin 158. A projection 190 on the arm 187 is provided with an elongated slot 191 so arranged that the arm 187 in adjusted position to the lever 157 by a nut andscrew 192 which passes through the slot 191. By swinging the arm 187 towards the right, one reduces the amount of motion transmitted to the work supporting spindles because the roller 180 will strike the pin 188 only at the upper portion of the roller and so contact therewith later and leave it sooner than would be the case if the pin 188 were lowered to be struck by the roller near a horizontal diameter. As showt "n the drawings, the arm 187 is adjusted to tue extreme left hand position to give a maximum relative movement to the work supporting spindles.

To vary the distance between the work supporting spindles, I provide the

spindles

20 and 21 with threaded

portions

200 and 201. Surrounding these threaded portions are a pair of double race,

ball bearings

202 and 203 which engage the yoked portions 154 and may be locked other and held in Y155 of

levers

150 and 151 respectively. To

adjust the positions of the ball bearings relative to the spindles, I provide a pair of

nuts

204 and 205 so arranged that the ball bear ings may be moved along the threaded

portions

200 and 201 and then locked in position. This adjustment varies the distance between the work engaging members on the spindles' to accommodate different. lengths of work.

As a further means tif varying the distance between the work supporting spindles to accommodate various lengths of work, I make the connecting rod or link 159 adjustable in length. This is preferably accomplished by means of a turnbuckle or other suitable arrangement. As shown, I may screw thread each end of the rod 159 and mount the threaded couplings 206 and 20T thereon.

Lock nuts

208 and 209 are provided respectively to lock the couplings in adjusted posi-tions. After removing the pivot pin 165 from the pivotally mounted coupling 206 and loosening the lock nut 20S, the operator may turn the coupling 206 relative to the rod 159 to shorten or lengthen the distance between

pivots

165 and 158 and thus vary the distance between the ends of the work supporting spindles. Likewise the other pivot pin 158 may be removed and the coupling 20T adjusted if a further adjustment is necessary.

To prevent a rapid dropping of the weight 170 and consequentlyv a too sudden motion of the spindles 2O and 21 in gripping a new piece of work, I preferably mount the weight 17() so that its lower portion acts as a dash-pot piston (see Fig. 3). The piston or weight 170 is surrounded by a dash-pot cylinder 210 which is provided with an opening to the atmosph'ere controlled by an adjustable air valve 211 so arranged that the leakage of 'air may be regulated to cushion the motion of the weight. By varying the weight 17() and the adjustment air valve 211, the spindles may be moved slowly or rapidly towards each frictional contact with the ends of the work to be ground with sufficient pressure to support and rotate the work during the grinding operation.

The bottom of the dash-pot cylinder 210 is provided with a series of openings or holes 212 to allow air'to leak rapidly into the cylinder on the up stroke of the piston or weight 170 and prevent retarding the releasing movement of the work supporting spindles. To prevent air escaping vfrom the cylinder through the holes 212 during the downward motion of the piston, I vplace a soft, iiexible disk 213 of leather, rubber or the like in the bottom portion of the cylinder. The disk 213 acts as a valve and prevents the escape of air on the downwardmovement of the piston, but permits air to readily raise the disk and enter the cylinder on the upward movement ..65 of the piston.

lVor feeding mechanism To make the grinding machine fully automatic l provide means for feeding the work automatically into grindingposition onvthe machine. As illustrated in Figs. 5, and 7, my preferred form of magazine feeding device comprises a turret wheel 23() having` openings in its periphery to receiv(` the pieces of work from the hopper 231. The operator places the new pieces of work in the hopper 231 and they roll down the surface 232 and into pockets 233 formed in the two disks 234 which make up the turret wheel 230. This wheel is suitably mounted to rotate about an axle 235 carried on uprights 236 supported on the machine base. A projecting lug 237 is mounted on the inside surfaces of each upright 236 to prevent the new piece of work 238 dropping into pocket 233 in the turret while grinding is goingon, and at the same time keeping two pieces from getting into the pocket at once. lVhen the turret wheel rotates, the piece supported on the shelf formed by lugs 237 is forced into the adjacent pocket, and another piece of work rolls onto the shelf in the next pocket as it comes into position. v y

The turret wheel 230 may be rotated to present new pieces of work to the work supporting spindles by any desired means, but in my preferred constr ction, I utilize Ithe iniuence of gravity to `turn it and employ a cam operated mechanism to release the turret when` the spindle gripping members have dropped the finished piece of work, and permit it to turn just enough to present the next piece to the work supports. To this end, I provide the side of the turret 230 with a ratchet wheel 240. A ratchet pawl 241 is sldably mounted in the boss 243 which is fixed to the upright 236. The ratchet pawl is held by spring pressure in engagement with the teeth of the ratchet wheel 240 to prevent rotation of the turret wheel inI a direction to feed the work. To release the pawl 241 from the ratchet wheel 240 and permit the influence of gravity to act on the new pieces of work to turn the turret wheel, Ipreferably connect the ratchet pawl to the connecting rod 244 (Fig. 8), the other end-of which is adjustably connected to the lever 245 pivotally mounted on the side of the base. The lower end of the lever 245 is provided with a cam face 246 adapted to be engaged by a second lever 247 pivoted to the base by 1 a cap screw 248. The lever 247 is connected by means of a connecting link 249 to a projecting portion of the follower lever 132 so that motion of the cam follower 133 due to the abrupt rise portion ofthe cam is transmitted to raise the lever 247 and cause it to swing and contact with the cam portion 246 and thereby move the lever 245 to withdraw the pawl 241 from engagement with the 230 so that each ratchet wheel 240. This permits the force of gravity acting upon the new pieces of work in the turret wheel 230 to turn the wheel rapidly to bring the next piece of work into axial alignment with the work supporting spindle. To keep thel turret wheel 23() from rotating too far and permit it to rotate just sufficiently to bring the next piece of work into axial alignment. with the work supporting spindles, I provide the ratchet wheel 240 with the same number of ratchet teeth as there are work openings in the turret wheel 230. -A reduced portion of the ratchet pawl 241 within the projection 243 isl surrounded by the spring 242 which exerts a suiiicient pressure to hold the pawl in position in contact with the ratchet wheel. The cam face 246'of the lever 245 is so shaped that the ratchet pawl may return' rapidly into. contact with the next ratchet tooth under the influence of the spring 242 as soon as the lever 247 passes over the cam face 246. This movement is suiiiciently rapid so that the pawl catches in the notch next to the one from released, and so stops the wheel when the next work piece is opposite the spindles. In order that the lever 247 may ride downwardly over the cam face 246 without removing the pawl from the ratchet whee1,I preferably make the lever 247 (see Figs. 8, 10 and 11) in two parts. As shown in Fig. 11, the outer swinging portion 251 is pivotally mounted to the lever 247 and is so shaped that on the upward movement, the lever 247 and portion25l act as a single lever. On the downward movement, however, the portion 251 contacts with cam face 246 and swings upwardly so that it may pass by the cam face j 246 without moving the ratchet pawl. When released from the supporting spindles, the piece of work that has been ground falls slightly into contact with its pocket and remains there to aid in turning the wheel to bring the successive pieces of Work into their propergrindin positions. As shown in. Fig. 5, the piece o work remains in the wheel until it is free to roll downwardlyinto a container 250 on the front base of the Inachine.

To position the pieces of work axially, I provide one of the uprights 236 with a spring 252 which projects so as to press against one end of the piece of work and force it to the right,'as shown in Fig. 6, against the-opposite upright or support 236 of the wheel piece of Work is presented to the Spindle inl the same relative position. This spring 252 is preferably provided with an adjusting screw 254 threaded into the support 236 so that the tension of the spring may be adjusted.

Work supporting aie/ vices Of the various forms of work gripping and supporting devices which I may employ, I

which it has just beenand 2l may withdraw have illustrated two types (see Figs. 3 and 14) which are adapted for holding solid and hollow pieces respectively. In the forni shown in Fig. 3, I utilize the cup centers 255 and 256 which are so shaped that they contact with the ends of the work 257 only adjacent the periphery of the workto center and drive the same. The weight 170 and linkage mech- -anism which areIP connected to move the work gripping members 25.5 and 256 axially are so adjusted that the weight holds these members against the work with sufficient pressure to rotate and center the' work during the grinding operation.

The device shown in Fig. 14 is particularly useful where it is desired to grind the outer cylindrical surface of a work piece concentric withan internal cylindrical surface. In this case, the spindles 20 and 2l are each provided with tapered apertures 26() and 261 respectively to receive the correspondingly tapered

members

263 and 264. The outer ends of the

members

263 and 264 are provided with the reduced portions 265 `and 266 respectively which are adapted to center the work by its central opening. The

portions

265 and 266 are preferably constructed with spring fingers formed by cutting radially extending

slots

268 and 269 in the reduced end portions, these serving to center the work even though there are slight variations in the diameter of the holes or openings 270 in the work. The work is gripped between two

collars

272 and 273 which are slidably mounted on the spring finger ends 265 and 266. The outward movement of these collars is limited by the

shoulders

274 and 275 on the tapered

spindle members

263 and 264. The inner ends of the collars are adapted to frictionally engage the ends of the Work with suicient pressure to rotate the Work during lthe grinding operation.

To permit the-spindles to withdraw from the finished Work, I employ

shedder members

276 and 277 mounted on the work supporting spindle housings on the front base of the machine. These shedder members extend downwardly and serve as yoke arms which engage the

annular grooves

278 and 279 in Athe slidable

members

272 and 273. When draw, the, shedder members hold the

slidable members

272 and 273 against endwise move-y ment so that the'worlr supporting spindles 20 from their gripping positions against the ends of the work.V This permits the turret wheel to be rotatedv to bring the new piece of work into axial alignment with the work supporting spindles.

P0we1l drieen turret wheel It may be desirable in grinding some kinds of work to provide a turret wheel which is positively Arotated to bring the new pieces of work successively into axial alignment with the work supporting spindles. To accomlish this, I may provide a mechanism which will operate intermittently to positively rotate the turret wheel to bring the work into grinding position. As shown in the drawings, such a construction comprises a turret wheel composed of the disks 234:a having pockets 233a to receive the pieces of work as they roll down the surfaces 232 of a hopper. The turret wheel is mounted for rotation on a shaft or stud 2841L supported in the

uprights

285 and 286 mounted on the machine base. A sprocket 287 is iixed on the wheel hub in the space between the disks 2343. A supporting bracket 288 is mounted on the machine base and has a shaft 289 journalled therein which carries a sprocket 290 on its outer end connected by a link chain 291 with the sprocket 287 t0 rotate the turret wheel. y

To cause the shaft 289 to turn the turret wheel at a proper time, I may connect this shaft with the wheel feed mechanism so that the work will be fed in timed relation with the movement of the grinding wheel. To accomplish this, I mount a ratchet wheel 293k on the other end of the shaft 289 and provide a ratchet pawl 294 on the bracket 295 which swings about the axis o the shaft 289 to pickup the successive teeth of the-ratchet wheel 293. a connecting rod 299 which is connected to the lever 130 so that as the feed cam 110 turns the lever 13()k is moved to revolve the turret wheel and bring successive pieces of work into grinding position. To prevent excessive rotation of the turret wheel which would carry the new piece of work past the 1nding position, I may employ a friction evice, which, as illustrated, comprises a friction collar or washer 296 held in frictional contact with the projection 297 of the turret wheel to retard the rotation thereof. I provide adjusting screws 298 which are screw threaded into the 'upri ht 286 and bear against the outer face o `the collar 296` toy vary the rictional contact between the washer 296 and the projection 297, By tightening or loosening thescrews 298 the friction between the collar and the turret wheel may be varied as desired.

A further modication of a turret wheel is shown. in Figs. 17 and 18, in accordance with which I utilize the weight and orce of the water stream, which is used to cool the work during the grinding operation, in order to aid in turning the wheel. The wheel is essen- To actuate the pawl, I provide' tially the same as that shown in Figs. 5 and 6 and is operated by means of the cam controlled mechanism shown particularly in Fig. 8 but it is provided with pockets, and shaped somewhat like a` water wheel, so that water may enter the pockets on the descending side nearest the grinding wheel and escape only when the pockets successively reach the bottom of their circular path of revolution. As illustrated, the work pieces 300 are supported on the sides 234b of the wheel, recesses-303 being cut therein to form projecting lugs 304i which curve in such a manner as to hold the work in place. The peripheral portion 305 of the wheel which connects the sides is cut away to form spaced openings 306 and a set of curved walls 307 are formed, as shown in Fig. 17, in such a manner as to provide deep pockets to hold liquid.` The sides 234b form the ends of the pockets and prevent the escape of liquid therefrom until the work has passed below the grinding wheel 19 and is to be discharged. The ratchet 240b corresponds with the ratchet 240 shown in Figs. 5 and 8, and it is by means of this ratchet control mechanism that the rotative movement of the wheel is regulated. The stream of water, diagramf matically illustrated as issuing from the pipe 310 which is normally used in a machine of this type, strikes against the adjacent openings of the pockets to the wheel, and fills the pockets, and the weight of the water, in addition to the weight oi the work, serves to give the wheel a' quick rotary movement when the ratchet is released.

rEhe operation of the various mechanisms of the machine is apparent from the above description. In this machine, which is fully automatic in operation, the work is placed in yly from the turret to support and rotate the work during the grinding operation. This is accomplished by vmeans of the weight 170 which moves at a rate determined by the valve adjustment of the dashpot 210. The motion of the weight is transmitted simultaneously to the two spindles by the linkage mechanism shown in Fig. 3.

The Fcam controlling mechanism shown in Figs. 1, 2, 8 -and 12 is constantly rotating, so that when the camroller 133 has passed over the sharp rise in the cam 110, the cross feed screw 81 vwill thenbe rotated bythe weight 143 in such a direction as to feed the grinding wheel into' the work. This goes on until the short time thereafter, the roller 133 is held out of contact with the cam While the grinding Wheel iinish grinds the work. During this interval thecrossfeed mechanism is stationary.

Then the cam roller 133 starts up the steep rise of the cam 110 and moves the grinding Wheel back rapidly against the pull of the weight 143. When the Wheel is out of contacty with the work, the roller 180 which is revolved by the cam shaft 111 then strikes the projecting member 188 on the spindle operating mechanism and thereby forces the spindles to separate and Withdraw the work supportino' members from engagement with the ends of the Work. The Work then drops into its former position on the turret wheel, and a ratchet mechanism (see Fig. 8) operating in timed relation with the wheel cross feed mechanism is moved to release the turret Wheel and permit it to revolve under the influence of gravity and bring the next piece of work into substantial alignment with the work supporting members, and the cycle of operations grinding Wheel rotatably mounted thereon,

is then repeated.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. A grinding machine comprising a base,

a grinding Wheel rotatablymounted thereon,

a pair of aligned, rotatable, axiallymovable, work supporting spindles arranged to ip and rotate a Work piece Vduring grin ng, means to move the Wheel towards and from the Work, and a single operating device to move both of said spindles simultaneously through the same distance to gri the Work, which acts in timed relation wit the Wheel movement.

2. A grinding machine comprising a base, a grinding Wheel rotatably mounted thereon, a pair of aligned rotatable work supporting spindles, each of which is movable axially toward and from the other to grip and rotate a Work piece in operative engagement with the grinding wheel, and means to vary the pressure with which the Work s indles grip the Work during grinding to equa ize the pressure thereof on the work.

3. A grindin machine comprising abase, a grinding whee rotatably mounted thereon, aligned rotatable axially movable work supporting spindles to support and rotate a work piece, means including a cam mechanism to feed the grinding wheel toward and from the Work through an invariable cam cycle to grind the work, means operating in timed relationgwith said cam mechanism to grip and release a Work piece before and after grinding it and means to adjust the time at which the work piece is gripped and released.

4. A grindin machine comprising a base, a grinding whee rotatably mounted thereon,

rotatable axially movable work sup ortingV spindles to support and rotate a wor piece,

means including a cam mechanism to feed the grinding Wheel toward and from the Work through an invariable cam cycle to grind the Work, means operating in timed relation with said cam mechanism to separate said spindles and means to vary the length of time during which the spindles are separated When releasing a finished piece of work.

5. A grinding mach'ine comprising a base, a grinding wheel rotatably mounted thereon, a pair of rotatable axially movable Work supporting spindles to grip and support a Work piece during the grinding operation, means including a cam mechanism to feed the grinding Wheel toward and from the Work through an invariable cam cycle, means operated in timed relation With said cam mechanism to adjust the time at which the Work gripping spindles separate relative to the movement of said cam mechanism to release a finished piece of Work and means to vary the length of time during which the spindles remain separated.

6. A grinding machine comprising a base, a

rotatable axially movable work supporting members adapted to support a Work piece in yoperative relation with the grinding Wheel,

means to positively separate said members, means including a yieldable device to move the members towards each other to grip the Work and means for controlling and varying the rate of such movement of the members towards each other.

7. A grinding machine comprising a base, a grinding Wheelrotatably mounted thereon, rotatable axially movable Work supporting members adapted to support a Work piece in operative relation with the grinding Wheel and an adjustable Weight and dash-pot arranged to control the rate of movement 'of said supporting members toward each other in gripping a Work piece.

8. A grinding machine comprising a base, a grinding Wheel rotatably mounted thereon, a pair of rotatable axially movable Work supporting spindles, one of which is movable axially toward and from the other, to grip and rotate a Work piece, and means to move said spindles relatively toward and from each other, including an adjustable Weight and dash-pot to control the rate of movement of said spindles toward each other in gripping a work piece.

9. A grinding machine comprising a base, a grinding Wheel rotatably mounted thereon, a pair of rotatable axially movable `Work grip'- ping and rotating spindles, means to move said spindles simultaneously toward and from each other, and an adjustable Weight and dash-pot to control the rate of movement of said spindles toward each other in gripping a Work piece.

10. A grinding machine comprising a base, a grinding Wheel rotatably mounted thereon,

work support-ing and rotating spindles ada ted to support a work piece in operative re ation with the grinding wheel, means to control the movement of said members including a weight and dash-pot to move said spindles toward each other to grip a work piece and positively actuated mechanism to separate said spindles after grinding to release the work piece.

11. A grinding machine comprising a base, a -grinding wheel rotatably mounted thereon, work supporting and rotating members in axial alignment, a turret wheel to support a plurality of work pieces and present them successively to said members, means'including a cam mechanism to feed the grinding wheel toward and from the work through an invariable cam cycle, positively actuated means o erated in timed relation with the cam mechanism so arranged that the turret Wheel rotates a suilicientdistance to present a new piece of work into operative association with the work supporting members andl the grinding wheel while the wheel is out of contact with the work.

12. A grinding machine comprising a base, a grinding wheel rotatably mounted thereon, a pair of rotatable work supporting spindles, one of which is axially movable towards the other, arranged to support and rotate a work piece in operative relation with the grinding wheel, a turret wheel to convey work pieces successively into alignment with said spindles, means including a cam mechanism to feed the inding wheel toward and from the work t rough an invariable cam cycle, positively actuated means operated in timed relation with the cam mechanism to separate said spindles and thereby release the finished work piece into the turret and means actuated by said cam mechanism to permit the rturret wheel to rotate a; sufficient distance to present a new piece of work into substantial alignment with the work supporting spindles.

13. A grinding machine comprising a base, a grinding wheel rotatably mounted thereon, a pair of rotatable axially movable work supporting spindles to support and rotate a work piece in operative relation with the grinding wheel, a turret wheel to convey work pieces successively into alignment with said spindles, means including a cam mechanism to feed the grinding wheel toward and from the work through an invariable cam cycle, positively actuated means operated in timed relation with the cam mechanism to separate said spindles and thereby release the finished work piece, means actuated by said cam mechanism to rotate the turret wheel a suiicint distance to present `a new piece of work into substantial alignment with thespindles anda yieldable mechanism to simultaneouslymove the s indles toward each other to gripthe new plece of work. o

14. A grinding machme comprismg a base, a grinding wheel rotatably mounted thereon, rotatable axially movable work supporting and rotating spindles, a. turret wheel arranged to convey successivev pleces of work into substantial alignment wlth the work supporting 'spindles'fsaid turret being so arranged that the work piece moves into a position with its axis slightly below the ax1s of the supporting spindles, andl work engaging members on the work supporting spindles which are shapedso as.. to grip the piece of work, center it1andraise it out of contact with the turret for the grinding operation.

-1-5. A grinding machine comprising a base, a grindingxwheel rotatably mounted thereon, work gripping and rotating members, meansiii'c'luding a cam mechanism to feed said grinding wheel toward and from the work through an invariable cam cycle, a

rotatable turret wheel to convey successive y pieces of Work into operative position, means to-hold said turret against rotation during1 the grinding operation and means operate in -timed relation with said cam mechanism to rotate the turret wheel a sufficient distance to present a. new piece of work into substantial alignment with said members.

16. A grinding machne comprising a base, a grinding wheel rotatably mounted thereon, work gri ping and rotating members, means inclu ing a cam mechanism to feed said grinding wheel towards and from the work through an invariable cam cycle, a rotatable turret wheel to convey successive pieces of work into operative position, means including a pawl and ratchet wheel to control rotation of said turret and means operated in timed relation with saidcam mechanism to actuate said pawl to rotate the turret Wheel a suflicient distance to present a new piece of work into substantial alignment with said members.

Signed at Plainville, Connecticut, this 20th day of June, 1928.

CHARLES H. NORTON.