US2101790A - Grinding machine - Google Patents

Description

DCC. 7, R, AI CLE ET GRINDING MACHINE Filed oct. 14, 193e 2 Sheets-Sheet l l EN um CM AA DH. ms MM YR AA RH Dec.7,1937. RA. COL ET AL 2,101,790

GRINDING MACHINE Filed Oct. 14, 1936 2 Sheets-Sheet 2 53 5 1 @www RAYMOND A. CV'U/ E CHAR/ Es H. AAq/no/v 45 @www www Patented Dec. 7, 1937 PATENT OFFICE 2,101,190 GmNDmG MACHINE Raymond A. Cole and (Jharles Il. Amidon, Worcester, Mass., assignors to Norton Company, Worcester, Mass., a corporation of Massachusetts Application ommen 14, 1930, serial No. 105,566

7 Claims.

This invention relates to a grinding machine, and more particularly to an electrical and hydraulic control mechanism therefor.

On'e object of the invention is to provide an improved hydraulically operated. grinding may chine with an improved cycle control mechanism.

A further object of the invention is to provide an improved live spindle headstock which is controlled by a manually operable cyclecontrol lever. itis a further object of the invention to provide a hydraulic control mechanism for the grinding wheel and the live spindle headstock which are controlled by a single control lever. A further object of the invention is to provide a hydraulically operated feeding mechanism with `an improved electrical'control therefor which is controlled or actuated by movement of a single control lever. A further object of the invention is to provide a cyclic wheel feeding mechanism which is electrically controlled. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the y mechanical features of this invention,

Fig. l is a front elevation of the improved grinding machine;

Fig. 2 is a sectional view through the live spindie headstock and through the hydraulic wheel feeding mechanism combined with an electrical and hydraulic diagram to illustrate the operation of the machine;

` Fig. 3 is a fragmentary sectional view, von an enlarged scale, taken Oapproximately on the line 3-3 of Fig; 2, showinglzthe pivot for the swivel table;

Fig. 4 is a fragmentary sectional view, on an enlarged scale, through the expansion work supporting arbor; and

Fig. 5 is a fragmentary sectional view, on'an enlarged scale, through the work ejector actuating mechanism.

A grinding machine has been illustrated in the drawings comprising a base III which supports a longitudinally movable work table on a V- way i2 and a at way I3. AThe work table may be traversed longitudinally either manually or by power by any of the well-known manual or power operated mechanisms. lFor simplicity of illustration, a manually operable traverse mechanism has been-illustrated. A rack bar |5depend ing from the table meshes with a gear I6 which is supported on a shaft The shaft I1 also supports a gear I8V which is either formed integral -with the gear i6 or is rigidly connected thereto and arranged to rotate therewith. The gear I3 meshes with a gear I9 carried on the inner end of a rotatable shaft 20. The outer end of the shaft supports-a manually operable traverse wheel 2|. By rotating the hand wheel 2| in either direction, the work supporting table may be moved longitudinally in the desired direction.

This machineis particularly adapted for grinding a work piece-- by means of -the plunge-cut method, that is by feedingthe grinding wheel directly into the work. It isin such an ,operation that it is desirable to provide a locating mechanism for the work supporting table, whereby the table may be readily positioned in the-desired position for grinding. An adjustable dog is carried by a T-slot 26 in the front of the table A xed bracket 21 is mounted on the machine base and carries an adjustable stop screw 28 and a lock nut 29 which are arranged in the path of the dog 25 and serve to limit the longitudinal movement of the table I when the table is moved in a direction toward the right (Fig. 1).

A rotatable grinding wheel 30 is supported on one end of a rotatable grinding wheel spindle 3| which is journaled in bearings (not shown) in a transversely movable wheel slide 32. The wheel slide 32 is arranged to be moved transversely on ways (not shown) von the base I0. The'grinding wheel spindle 3| may be rotated in any of the well known manners, such as by means of an overhead drive shaft or countershaft or by means of an electric motor 33 which is mounted on the wheel slide 32. The motor 33 is provided with a motor shaft 34 which carries on its outer end a driving pulley 35. The pulley 35 is connected by driving `belts 36 with a pulley y3'l mounted on the outer end of the wheel spindle 3|. The belt drive above described is preferably of a multiple V-belt type in which a plurality of belts 36 of V-shaped cross sectional area are connected between a multiple V-grooved pulley 35 and a multiple )l-grooved pulley 31.

The wheel slide 32 -is arranged to be fed transversely toward or from the work supporting table I I by means of a wheel feeding mechanism to be hereinafter described.

Wheel feedingl mechanism A wheel feeding mechanism is provided .to control the feeding movement and adjustment of the grinding wheel 30 toward and from the work support. The wheel slide 32 is provided with a depending nut 4|! which meshes with a rotatable feed screw 4|. supported in bearings 42 and 43 in the base l0. The feed screw 4| may be rotated manually for adjusting the position of the wheel slide 32 in setting up the machine by a manually operable feed mechanism, to be hereinafter described.

In order that the wheel slide may be rapidly The feed screw 4| is rotatably moved toward the work piece to grind the same `by the plunge-cut method, the feed screw 4| is connected, to a piston rod 44. A fluid pressure 'cylinder 45 is arranged in axial alignment with the feed screw 4| and contains a slidably mounted piston 48 which is connected with the piston rod 44. A fluid pressure pump 41 is mounted to be driven by a shaft (not shown) or by an individual motor drive (not shown) to pump fluid through a pipe 4s from a reservoir 4s within the base I8. The pump 41 forces fluid under pressure through a pipe 58 to a feed control valve 5|. The feed control valve 5| preferably is of a piston type comprising a valve stem 52 and pistons 53, 54, 55, and 58. In the position of the valve 5| (Fig. 2), fluid under pressure enters the valve chamber` 51 between the valve pistons 54 and 55 and passes out through passage 58 into a cylinder chamber 59 to cause the piston 48 to move rearwardly to withdraw the wheel slide 32 and grinding wheel 38 to an inoperative or. rearward position away from thev work piece. During the passage of fluid under pressure into the cylinder chamber 59, fluid is exhausted from a cylinder chamber 88, through a passage 8 I, into av valve chamber 82 between the pistons 53 and 54, and out through'a pipe 83 which exhausts into the reservoir 49.

The valve stem 52 is held in a rearward posi- .tion (Fig. 2) by means `of a spring .84 whichis 4is connected to the outer end of the rock arm 85. The solenoid 18, when energized, serves to move the valve stem 52 into its reverse position so that fluid under pressure passing through the pipe 58 into the valve chamber 51 passes through the passage 8| into the cylinder chamber 88 to Acause the piston 48, to feed screw 4| and the wheel slide 32 to move the grinding wheel 38 into a grinding position with relation to the work piece., I

The piston and cylinder mechanism, above described, serves to cause the grinding wheel 38 rapidly to approach or recede from the work piece. In order to reduce the rapid approaching movement to a predetermined grinding feed, it is desirable toprovide a wheel feed controlling mechanism, such asa dash pot mechanism, which may be rendered effective when the grinding wheel 38 is about to contact with the surface of the work piece being ground. As illustrated vin Fig. 2, an outwardly extending casing 1| is fixed to the end of the cylinder 45 and contains a pair of diametrically spaced dash pot pistons 12 and 18 which slide within dash pot cylinders 14 and 15. The dash pot pistons 12 and 13 normally are held in a rearward position by springs 18 and 11, respectively. During the rapid approach of the grinding wheel 38, the dash pot pistons are inoperative.

`The piston rod 44 extends toward the rear of so arranged that the sleeve 18]' moves rearwardly whenthe piston rod 44 moves into a rearward position. The fdash' pot pistons V12 and 13 are limited in their rearward movement by means- -18 which forces fluid under pressure from the dash pot cylinders 14 and 15 into a dwell Vcontrol mechanism to be hereinafter described. 'The dash pot cylinders 'I4 and 15 'are interconnected by a passage 85 and exhaust fluid| through a pipe 88 into a chamber 81 of a dwell control valve 88, as shown in Fig.- 2, which will be more fully described hereinafter.

- Positive stop In order to grind a work piece to a predetermined sizve, it is necessary to feed the grinding wheel 38 toward the work piece to grind the same and then to stop the infeed and allow the grinding wheel 38 to grind-out or to allow the sparks to die-out in order to roundup the work so that it will be ground to a cylindrical surface of a predetermined size. As illustrated in Fig. 2, the forward movement of the piston rod 44 causes a rapid approach until the' sleeve 18 picksup the dash pot pistons 12 and 1 3 to cause a slow'infeed which continues until an adjustable sleeve 98- engages a xed surface 9| on the rear end of the casing 1|, thereby positively limiting the infeeding movement of the wheel 38 and causing the wheel to dwell in contact with the work during a finish grinding period. The adjustable stop sleeve 98 surrounds the sleeve 18 andisheld in adjusted position thereon by means of lock nuts- 92.

. Wheel 'feeddwell control In order to provide a predetermined but adjustable dwell ,at the end of the grinding operation to allow the wheel 38y to grind out or finish grind the work, a dwell control mechanism is operatively connected with the dash pot mechanism. The dwell control unit comprises the vertical valve 8.8 having a piston 94 slidably mounted therein. Fluid under pressure exhausting from the dash pot cylinders 14 and 15 passes through the pipe 88 into the valve chamber 81 in the lower end of the valve 88 to cause an 4upward movement of the piston 94. The piston 94 is provided with a vertically extending piston rod 95 which carries at its upper end .an adjustable arm 98. The arm 98 is provided with an adjustable stop screw 91 which in the lower position engages the upper surface 98 of the bushing 99 of the valve 88. I'he screw 91 limits the downward movement of the piston 94. Associated with the dwell control unit is a normally open mercury switch |88 which is supported on a 'pivotallymounted plate |8|.` 'Ihe` plate |8| is pivotally supported on astud |92 dand is provided'with an extending arm |83'which extends into the path of a vertically extending rod 84. The rod |84 passes through an aperture in the arm 98 and carries a pair of adjustable collars |88 and |81 which serve to provide adjustable connections between the rod |84 and the arm 98 to rock the mercury switch |88.

When fluid under pressure is admitted to the dwell control valve chamber 81 to cause the piston rr94 and the piston rod 95-to move upwardly, the

passes through a passage I|| in the bushing 99.'

The piston rod 95 is provided with a- V-shaped groove I3 which allowsuid passing through 'the passages and to pass along the V-shaped groove ||3 during the upward `ovement 'of the piston rod 95 and 'out through a passage, ||4` in the casing 98,'through a pipe H5, into a fluid reservoir H6 mounted on the casing 1 I- located above the dash pot cylinders 14 and 15. During the upward movement of the pistonl94, fluid within a valve chamber ||1 of the valve 89 may pass outwardly through a passage ||8 and through a ball check valve ||9 in the passage ||8, through pipe and into the uid reservoir H6.

The piston 94 moves rapidly in an upward direction until the piston rod 95 engages an adjustable stop screw which is supported in a bracket |2| fixed to the valve head 98. By adjusting the position of the stop screw |20, the upper position of the V-shaped groove ||3 may be adjusted and, due to the V-shaped cross sectional area of the groove and the fact that this groove I I3 tapers tozero at the end of the groove, A vserves to control the rate of uid exhaust from the dash pot chambers 14 and 15 and thereby control the grinding feed. l

The v-shaped groove H3 in its upward position serves to restrict the exhaust of 'fluid from the dash pot chambers 14 and 15 so as to control the rate of infeed of the grinding wheel during the grinding operation. When the grinding wheel 30 is fed toward the work piece by means of the fluid pressurepiston 46, the rapid approaching movement continues until the bushing 18 engages the ends of the dash pot pistons 12 and 13, after which the exhaust of fluid from the dash pot chambers and 15 fromlthe dwell control unit servesto slow down the rate of movement of the grinding wheel 30 to a predetermined grinding feed. As .soon as the sleeve 18 picks up the dash potpistons 12 and 13 and causes them to move, tl'e exhaust of fluid from the dash pot chambers 14 and 15 moves the dwell control valve piston Sli'upwardly, compressing the spring |22, and

rocking the mercury switch |00 so as to close the The mercury switch |00 is connected' circuit. through an electric circuit to-be hereinafter de` ,scribed with the solenoid 10. The piston 94` remains in its upward position during the movement of the dash pot pistons 12 and 13, which continue to move forward until the adjustable stop sleeve 90 strikes the xed stop surface 9|,

thereby preventing further advance ofthe dash pot pistons -"I2 and 13. As soon. as the exhaust of iiuid from the dash pot cylinders 14 and 15 ceases,

the released tension of the spring |22 and the.

force of gravity acting upon the piston 94 and its associated parts starts a downward movement of the piston 94. This downward movement serves to create a partial vacuum in the chamber I1 of the valve 00.v Fluid enteringinto the chamber I1 cannot pass through the ball check vaive-| I9 and passes through a passage'or pipe/|26 and anl adjustable needle valve |26 into the chamber ||1. The pipe |25 is connected to the pipe ||5 to pass fluid into reservoir H6. The needle valve |26 may be readily adjusted vto control the downyward movement of the piston 94 and thereby CTI mercury switch |00 and again open the circuit,

which deenergizes the solenoid 10 so as to allow the released tension of the spring 64 to shiftthe reverse feed control valve 5| and to cause a rearward movement of the grinding wheel slide 32, as will be hereinafter more fully described.

On the return stroke of the grinding wheel, the

springs 16 and 11-return the dash pistons 12 and 13 to a rearward position in engagement with the adjustable stop screws 8| and 82, respectively. During this movement the dash pot cylinder chambers 14 and 15 are refilled byfluid under pressure from the reservoir ||6 passing through the pipe ||5 and a ball check valve ||2 so that on the next forward feeding movement of the grind-- ing wheelQthe dash pot cylinders are filled and ready to control the infeed of the grinding wheel. In order to ll the reservoir ||6, a pipe 09 is connected with pipe so that iiuid from the` pump A41 maypass .through a control valve 93 and a pipe 89 into the reservoir to ll the same. An overiiow pipe I 05 serves to prevent the fluid rising beyond a predetermined level in the reservoir I6. The overflow pipe |05 is connected to' pipe 63 which exhausts into the reservoir 49. The

f valve 93 may be opened when desired by the opererator to refill the reservoir ||6 to take care of any leakage or, if desired, the valve 93 may be partially opened to allow a continuous flow of fluid into the reservoir to maintain the oil level within the reservoir ||6 at all times.

Manual feed adjustment gear |28 which meshes with a gear |29 rotatably mounted on the inner end of a shaft |30. The other end of the shaft |30, which projects from the front of the base I0, supports a manually operable feed wheel |3I.

The feed screw 4| may be rotated manually by rotation of the manually operable feed wheel |3| in either direction to adjust the position of the wheel slide 32 and the grinding wheel 30. A stop pawl |32 is pivotally mounted by a stud |33 on the base I0. The pawl |32 isarranged to engage an abutment (not shown) carried by the manually operable feed wheel I3I. The feed wheel is provided with a manually operablemicromfeter adjusting mechanism |34 to facilitate adjustment of theabutment relative to the feed Rotatable worlc support A rotatable work support is provided on the table II to support a work piece in operative relation with the grindingwheel 30 for a grinding operation. In the preferred construction,'a live spindle work rotating and supporting mechanism is provided comprising a headstock |36 which is arranged rotatably to support a spindle |36 in bearings |31 and |38. The heads'tock |35 is provided with surfaces |39 which mate with correspondingly shaped surfaces on a swivel table |40 which is supported on the table The headstook |35 is arranged to be clamped in position on the swivel table by means of a clamping member |4| and a clamping screw |42.

The swivel table |40 is provided so that the axis of rotation of the work rotating spindle |36 may be adjusted relative to the path of movement of the table so that either a true cylinder may be ground or a tapered surface, as desired. The swivel table |40\is pivotally supported on a pivot pin |43 which is secured within the upper surface of the table ||,and which engages an aperture within the swivel table |40. A bolt or stud |44 passes through the table I, the pivot |43, and the swivel table |40 to hold the swivel table in adjusted position thereon and prevent lifting of the swivel table |40 relative to the table A swivel adjustment is provided at the other end of the swivel table. A bracket |45 is adustably sup-u ported bybolts |46 which slide in the T-slot 26 in the front of the table An adjusting screw |41 is connected at its inner endby a stud |48 which is secured to the swivel table |40. The outer end of the screw |41 passes through an aperture within the bracket |45. Thrust washers |49 and |50 are mounted on the screw |41 on either side of the bracket |45. A pair of nuts |5| and |52 carried by the screw thread |41 serve to adjust and to lock the screw |41 in adjusted position. By manipulation of the nuts 5| and |62, the left-hand endof the swivel table |40 (Figs. 1 and 2) may be adjusted transversely so that the axis of rotation of the spindle |36 may be adjusted so that it is parallel to or at an angle with the path of movement of the table to grind either a true cylinder or a tapered'work piece thereon.'

After the swivel table has been adjusted into the desired position, the nuts |5| and |52 are locked in adjusted position and the bolt |44 tightened to lock the swivel table |40 in rigid adjusted posin tion with the table The work supporting spindle |36 may be rotated by an electric motor |60`which is mounted on top of the headstock |35. A motor shaft |6| `is provided with a V-grooved pulley |62 which is connected by multiple V-belts |63 with a pulley |64 which is keyed to the end of the work spindle |36v and is held in adjusted position thereon by a collar |65.

In order to tension the driving belt, the motor |60 is preferably mounted on a. pivotally mounted support |68 which is connected by pivot pins |69 with the headstock |35. The rear end of the pivotal support |68 is provided with an adjusting screw |1| by means of which the pivotal support |68 may be adjusted so as to tension the driving belts |63, as desired.

In order that the motor |60 may be readily controlled from the operators station in front of the machine base, a two-button snap switch |12 is mounted n the front of the machine base.

. A suitable end thrust Vbearing is provided to pick up the end thrust of the rotatable work supporting spindle |36. A sleeve |15 fits on a reduced portion |16 of the spindle |36 and is keyed thereto by means of a key |11. The sleeve |15 is held in position onr the spindle by means of the collar |18 which is screw threaded onto the reduced portion |16 of the spindle |36. The sleeve |15 is provided with an integral ange |19 which engages one side of a fixed thrust member |80. The thrust member has diametrically opposed projections |8| and |82 which are secured to the headstock frame |35 by screws |83 and |84. An adjustable thrust collar surrounds the sleeve |15. One end of the sleeve |15 bears against the fixed thrust member |80. A pair of adjustable thrust collars |86 are screw threaded onto the end of the sleeve |15. By adjusting `the collars- |86, the end thrust of the spindle may be adjusted, as desired, to take up the thrust of the spindle during the grinding operation.

In grinding of certain types of work, it is desirable to provide a live spindle work supporting member which is. arranged so that work pieces may be inserted, ground and ejected therefrom without stopping the rotation of -the spindle. Such -a mechanism has been villustrated in the drawings. A c ollet supporting member |90 fits within a tapered aperture |9| in the end of the work spindle |36. The outerend of the collet supporting member |90 is provided with a tapered portion |92. whichis arranged to support a split ex' pansion arbor or collet |93. The collet |93 is held on the tapered portion |92 by means of a plurality of pins |84 which pass through the slots |95 in tire collet member |93 and are iixed in the tapered portion |92 of the collet supporting member\l90. 'Ihe outer surface |96 of the collet |93 is of a size `to fit the aperture within the work piece |81. In order to expand the arbor or collet |93, a frustoconical expanding member |91 is provided on the outer end of a slidable sleeve |98. When the sleeve |98 is drawn or moved toward the left (Figs. 2 and 4), the frusto-conical expansion member |91 engaging an internal frusto-conicalfsurface |99 within the collet |93 expands the same securely to lock the work piece |81 in operative relation to rotate with the spindle |36. The sleeve y with a reduced threaded portion-'20| which projects from the end of the spindle 36. In order automatically to expand or contract the collet |93, the sleeve 200 is moved either toward the right or toward theleft (Figs.`2 and 4). It is desirable to provide means for automatically clamping or releasing a work piece on said collet. This is preferably accomplished by means of a power actuated mechanism.' A spring 202 is .contained within an enlarged aperture in the spindle |36 and is interposed between a shoulder in said aperture and a collar 203 carried by the sleeve 200. The tension of the spring 202 may be adjusted by ,means of a collar 204 screw threaded onto the sleeve 200. The spring 202 is provided having suilicient compression to move the sleeve 200 toward the left (Figs. 2 and 4) so as to move the expansion member 91 also toward the left (Fig. 4) to expand the collet |93 to hold the work piece |81 in operative position for a grinding 'The piston 208 is .connected by a piston rod 209v and a pin or stud 2|0 with the lower end of a.I

rock arm 2||.. The rock arm' 2H is pivotally supported on a stud 2|2 carried by a bracket 2|3 which is fixed to the headstock |35. The other end of the rock arm 2|| is yoke shaped .and is connected by pivotaliy supported shoes 205 withA a groove 2I4 in a spool shaped member 2|5 which is slidably mounted on a reduced portion of theA amount of lost motion in said connection may be adjusted as desired.

When it is desired to release the work piece from the expansion arbor or collet |93; uid Yunder pressure is admitted through a pipe or passage 220 into a cylinder chamber 22 to move the piston 208 and the piston rod 209 toward the tween a nut 243 carried by the rod 236 and the left (Fig. 2) so as to rock the arm 2|| in a clockwise direction on its supporting pivot 2|2. During this movement of the rock arm 2| l, the spool shaped member 2|5 slides on the sleeve 200 until it engages `the thrust washer 2|1. Continued movement of the rock arm 2|| in a clockwise direction slides the sleeve 200 toward the right (FigsQZ and 4) which in turn moves the member |98 and the tapered collet closing member |91 also toward the right to allow the expansion collet |93 to contract to release the work piece |81. In case the collet |93 moves toward the right with the collet closing member |91, this movement can continue only a short distance until the pins |94 carried by the conical member |92 of the collet supporting member |10- engage the ends of the sl'ots |95 which holds the collet |93 against further endwise movement and allows the collet closing member |91 to withdraw a sufllcient distance to allow the collet |93 to contractand release the work piece |81.

After the work piece |81 has been removed and -a new piece of work inserted on the rotating collet |93, the iluid pressure within the pipe 220 is cut off and connected with the exhaust by a mechanism to-be hereinafter described, which serves to release the compression of the spring 202 which moves-the sleeve 200 toward the right to expand the collet |93 again to lock the nexti piece of work |81 in an operative position to rotate with the spindle |36. A spring 222 which surrounds the piston rod 209 andl is interposed between the piston 208 andthe left-hand end of the cylinder 201 (Fig. 2) serves to return the piston 208 to its initial position, asv illustrated in Fig. 2. A spring 222 cooperates with the spring 202 in closing the collet |93.

Eectig mechanism It is desirable to provide an ejector mechanism which will automatically-remove the work piece |91 endwise from engagement with the collet |93 when the collet is released. This is preferably accomplished by means of a short sleeve 225 which is slidably mounted on the member |90. A transversely extending pin 226 isiixed at opposite ends to the sleeve 225 andslides withinv elongated slbts 221 and 228 within the members |98 and |90, respectively. The pin 226 passes through an ejector rod 229, of two-piece construction, which is slidably mounted within the sleeve |98 threaded to the sleeve 200 and a bushing at the other end of the sleeve 200, as showny in Fig. 5. When the rod 229 is moved toward the right (Fig. 4), thefrod carries the pin 226 and sleeve 225 which engages the end of the work piece |81 and slides the same 0E the collet |93. It is desirable to provide a suitable mecha'- nism to snap the rod 229 quickly to remove the work piece |81 rapidly fromposition on thev collet |93. 'I'his is preferably accomplished by means of a load and re mechanism comprising a rock arm 230 which is pivotally mounted on a stud 23| supported on a bracket 2324. A spring 233 interposed between a stud 234 on the headstock and a stud 235 on the rock arm 230 serves to hold the rock arm 230 in the position illustrated in Fig. 2. A connecting rod 236 is 15 i pivotally connected to the rock arm 230 by means of a stud 231. The rod 236 slides within a sleeve 238 which is pivotally mounted on a stud 239 at one end of a rock arm 240. The rock arm 240 is pivotally mounted on a stud 24| on the bracket 232 projecting from the headstock |35. A spring 242 surrounds the rod 236 and. is interposed bethe-expansion collet |93.

When iiuid under pressure is admitted .to cylinder chamber 22| to contract the collet |93 toA release a work piece |81 after a grinding opera vtion has been completed, the initial movement of the spool-shaped member 2|5 serves, to rock the rock arm 230 and, through the connecting rod 236, serves to rock the rock arm- 240 in a counterclockwise direction so that the detent 245 engages the end of the ejector rod 229. Continued movement of the spool-shaped memberA 2|5`toward the left (Fig.` 2) serves to compress the spring 242 until the sleeve 200 moves a suicient distance to move the collet expanding member |91 toward the right to contract the expansion collet |93, whereupon the released tensio of the spring 242 quickly rocks the rock arm 240 and moves the ejector rod 229 toward the right (Figs. 2 and 4). This movement in turn moves the pin 226 and sleeve 225 rapidly to eject the work piece |81 frpm the collet |93 into a discharge chute- 250 which is supported on the table of the machine.

A fluid pressure control valve 25| is provided manually to control the admission of uid under pressure through the pipe or passage 220 into the cylinder chamber 22| and to exhaust fluid therefrom when desired.l A pipe 252 is connected with the pipe 50 and the pump 41 and passes uid into a valve chamber 253. In the position of the valve 25| (Fig. 2), iluid is exhausted from the chamber 22|, through the pipe or passage 220, into valve chamber 254, through sage 255 in the rotary valve-member 256, intovvalve chamber 251, and out through a pipe reservoir 49. When it is desired to release a work piece after a grinding operation, the rotary valve 256 is turned so that fluid passing through the pipe 252 into the valve chamber 253 passes through the -valve passage 255. into the valve chamber 254, and through the pipe 220, into the cylinder chamber 22|, to actuate the piston. 208

and its associated parts to release the expansion collet |93 and eject a work piece |81 therefrom.

258 which exhausts into the ont'rol mechanism Itis desirable to provide a simplified control for the machine so that the live spindle headstock |35 andthe cyclic control of the wheelfeed mechanism may be readily controlled by means of a single manually operable lever. A manually operable control lever 260 is pivotally supported by a stud 26| which passes through a collar 265 and a valve stem 262 which is formed integral with the rotary valve member 256. By rocking the lever 260 in a plane parallel to the wheel axes, the rotary valve member 256 may be shifted so as either to admit fluid to or exhaust fluid from the cylinder chamber 22| so as either to expand or contract the expansion arbor |93 and clamp or release a work piece 81 thereon. 'Ihe control 1ever 260 is held in a vertical position by means of a spring 264 which is supported in an aperture, part of which is formed within the pivotally mounted control lever 260, and the other part of which is formed in a bushing or collar 265 mounted on the end of the valve stem 262. In order to limit theswing of the lever 260 to rotate the rotary valve member 266, a projection 263 is provided to position the valve passage 255 to allow exhaust or intake to the cylinder chamber 22 In order that the wheel feed mechanism may Vbe controlled by means of the main control lever 268, it straddles the collar 265 so that a pair of normally open push buttons 268 and 269 mounted in the control valve 25| are arranged in the path of portions 210 and 21| of the control lever 268. ,The portions 210 and 21| of the control lever 260 are formed as arcuate members which are arranged so that in any position of the control lever, the portions 210 and 21| are in a position to actuate the push buttons 268 and 269, respectively.

To start the cyclic wheel feeding movement, the control. lever 260 is rocked in a clockwise direction (as shown in full lines in Fig. 2) to push the button 268 which serves to operate a relay- 215 which serves to .close a circuit to energize the solenoid 10. The energizing of solenoid 10 serves to shift the feed control valve 5| to initiate a forward movement of the grinding wheel 3|),V the cycle of movement of which continues under the control of `the hydraulic piston 46, the dash pot pistons 12 and 13, and the dwell control valve 88 which controls the extent of dwell and-then rer" turns the grinding wheel 30 and its supporting slide 32 to a rearward or inoperative position.

It is desirable to provide means for interrupting the cycle of operation of the machine and rapidly returning the wheel 30 and wheel slide 32 to their initial or rearward position when desired by the operator in case of trouble with the machine. In order to accomplish this result, the push button 269 is arranged so that when the lever 260 is rocked in a counterclockwise direction (Fig. 2), it serves to close a circuit, thereby energizing a relay 216. The energizing of relay 216 serves to break the .electrical circuit which holds the solenoid 10 energized for an infeeding movement' thereby deenergizing the solenoid 10 and releasing the tension uof the spring 64 which serves rapidly to move the valve stem 52 toward the right (Fig. 2) to reverse the flow of fluid under pressure and thereby admit fluid under pressure to th`e cylinder chamber 59 to cause a rapid rearward movement of the slide 32 and the grinding wheel 30. 'I'he lever 26|)l may be 'operated at any time during the grinding cycle in case of' dimculty in the operation of'the machine quickly to return the parts to a starting or inoperative position.

The cyclic wheel feeding mechanism above described serves to bring the grinding wheel- 30 forward to a predetermined position and then automatically to withdraw the grinding wheel 30 to an inoperative position. In case it is desired to true the grinding wheel 30, it is desirable to provide means whereby the grinding wheel slide 32 may be moved into -its forward position and retained there during the wheel truing operation.

A two-button snap switch 280 (Figs. 1 and 2)- Vserves when closed to close a circuit independent of the cyclic wheel feed mechanism above described so as to energizethe solenoid 10 which causes a forward -feeding movement of the'grinding wheel 30. The Wheel slide 32 moves forward until the stop sleeve 18 engages the Istop surface 9| on the end of the dash pot cylinder casing 1|.

The solenoid 10 remains energized, holding the 20 control valve 5| in a position to retain the wheel f The operation of this grinding machine is readily apparent from the foregoing disclosure.

Assuming the parts to have beerrpreviously adjusted so `that the desired grinding cycle is obtained and the live spindle work headstock |35 has been adjusted and set up for grinding a workl piece |81 of a predetermined size, a snap switch is operated to start the rotation of the motor 33 to rotate the grinding wheel 30, a second snap. switch is operated to start the fluid pressure Dlnnp 41, and a snap switch |12 is operated to start the rotation of the work rotating motor |60. The work piece |81 is then manuallyplaced in position on the expansion arbor |93 which is continuously rotated, the control lever 260 (dotted lines, Fig. 2) is then moved from position 260a to allow fluid Within the chamber 22| to exhaust through the pipe or passage 220 and valve 25| and pipe 258 into the reservoir 49. This movement releases the spring 222 and the spring 202 which serves to return the piston 208 to the position shown in Fig. 2 and to move the sleeve 200 toward the left (Figs. 2 and 4) so that the collet expanding member |91 expands the collet |93 to `hold the work piece |81 in an operative grinding position to rotate with the spindle |36.

The lever 260 (full lines, Fig. 2) is then moved in a clockwise direction to operate the push button 268 which serves to actuate the relay 215 so as to energize solenoid 10 which in turn shifts the control valve 5| to admit uid so as to cause a forwardfeeding movement of the wheel slide 32 and the grinding wheel 30. The control lever 260 is yheld in a position to had .push button- 268 in a closed position during the initial forward feeding movement of the grinding wheel 30 and until the sleeve 18 picks up the dash pot pistons 12 and 13 which exhausts uid through pipe 86 to cause an upward movementof the dwell control valve Piston 94. The upward movement of the dwell control piston 94 allows the mercury switch |00 `to rock in-a counterclockwise direction to close the circuit, which holdsthe solenoid 10 in an energized position, after which the control lever 260 may be released and the spring 264 returns it to the position illustrated in Fig. 2.

The infeeding movement of the grinding wheel 30 continues at a slow rate until the stop sleeve 90 engages the stop surface 9| at the rear of the dash pot cylinder casing 1|. The grinding wheel 30 remains in grinding contact with the work iece |81 until the piston 94, under the lnuence of the released tension of the spring |22, pushes down piston 94 at a controlled rate to rock the, mercury switch |00 again in a clockwise direction into the position illustrated lin Fig. 2, which movement serves to break the circuit, thereby deenergizing the solenoid 10. The deenergizing of the solonoid 10 releases the tension of the spring 64 which returns the valve 5| into the position illustrated in Fig. 2 to admit duid into cylinder chamber 59 to cause the grinding wheel 3|! and the wheel slide 32 to move to an inoperative rearward position.

When the wheel slide has withdrawn, the lever 260 may be rocked from position 260 (broken lines, Fig. 2) into position 260:1 which serves toshift the valve 25| so as to admit uid under pressure through the pipe or passage 220 into cylinder chamber 22| which operates through the associated parts above described to contract the collet |93 and eject the work piece |81 therefrom into the discharge chute 250. A new piece of work |81 may then be inserted on the continuously rotating collet |93 and the cycle of operation may xloe continued.

It will thus' be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embod'ment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted` as illustrative and not in a limiting sense. K

1. In a grinding machine, a. base, a rotatable grinding wheel, a transversely movable slide therefor, a rotatable work supporting spindle, a motor which is arranged continuously to rotate said spindle, a chuck on said spindle, means including -a fluid pressure piston and cylinder to control said chuck to` clamp or release a work piece thereon, means including a fluid pressure operated piston and cylinder operatively connected to move the wheel slide transversely in either direction, an electrical control mechanism for said uid pressure wheel feeding mechanism, a

. control valve to admit fluid to said chuck operating' cylinder, and a manually operable control lever which is arranged when moved in one direction to operate said valve and when moved in a second direction to actuate said electrical mechavnism to control the wheel feeding-movement.'

2. A grinding machine comprising a base, a rotatable. grinding wheel, a transversely movable slide therefor, a feeding mechaism including a iiuid pressure piston and cylinder operatively connected to move said slide transversely in either direction, a control valvetoVv controlthe' admission ofy uid to said cylinder, electrically operated means including a solenoid to actuate said valve, an electric switch which- .is operatively connected to control said solenoid, a continuously rotated expansible work supporting member, means including a fluid pressure piston and cylinder to expand or contract said work support to clamp a work piece thereon for a grindingoperation or to release it therefrom after a grinding operation has been completed, a controlvalve which is arranged to control the admission of fluidunder pressure to said second cylinder, and a control lever which is arranged when moved in one direction to actuate the valve and control the admission and exhaust of fluid to and from said'seccnd cylinder and when moved in a second direction serves to actuate said electric switch to control the transverse feeding movement of the grinding wheel.

.3. A grinding machine comprsing'a basefa rotatable grinding wheel, a transversely movable slide therefor, a feeding mechanism including a fluid pressure piston and cylinder to move said slide transversely in either direction, a control valve to control the admission of fluldunder pressure to said cylinder, an electrical solenoid to means including a piston and cylinder which are,r

operatively connected to contract said arbor and eject a Work piece therefrom, a control valve which is'arranged to admit fluid under pressure to the latter cylinder, and a control lever which is arranged when moved in one direction to actuate said control valve to control the admission of fluid to said second cylinder and when moved in a second direction to actuate an electric switch to control the feeding movement of the grinding wheel.

4. A grinding machine comprising a base, a rotatable grinding wheel, a` transversely movable slide therefor, a rotatable work supporting spindle, means including a motor which is arranged continuously to rotate said spindle, yieldable means to clamp a work piece on said spindle,

fluid pressure mechanism including a piston and cylinder to release said work piece,` an ejector actuated thereby to eject a nish ground work` piece therefrom, a rotary control valve operaltively connected to control the admission of fluid l to saidcylinder, a feeding mechanism including a fluid pressure pistonand cylinder operatively connected to move said slide transversely in either direction, a control valve to control the admission of `fluid under pressure to said feed y cylinder, electrically controlled means including a solenoid to actuate said valve, a switch located adjacent to said rst control ,valve and arranged to control said solenoid, and a single control lever which is pivotally connected to said valve stem and arranged when moved in one direction to rotate said valve to c ontrol the admission and exhaust of uid from said first cylinder ,and when moved in a second direction to actuat said switch and thereby control the transverse feeding movement of the lwheel slide. .v

5. A grinding machine wheel feeding mechanism comprising @rotatable grinding wheel, a trans'- yversely movable slide therefor, a duid pressure piston and cylinder operativelyconected to move said slide rapidly in either direction, adash`pot mechanism associated therewith and effective on the tiate an infeeding movement of the grinding wheel, an electrical switch operatively connected yto energize said solenoid to initiate an infeeding movement of the grinding( wheel, a second electric switch operatively connected and arranged to deenergize said solenoid to cause a rearward movement of the grinding Wheel', anda pivotally mounted lever which is arranged to actuate both of said switches.

6. In a grinding machine, a rotatable work spindle, means including a motor which isA arranged continuously to rotate said spindle, a work chuck carried by said spindle, a slidable sleeve within said spindle to actuate said chuck to grip a work piece thereon, yieldable means acting on said sleeve normally to hold said chuck in a gripping position.' a iluid pressure mechanism including a, piston and cylinder to actuate said sleeve and chuck to release the work piece, an

' ai'oifroo cause a rapid movement of said ejector when.. the y chuck has been released.

7. In a' grinding machine, a rotatable work supporting spindle, means including a motor arranged continuously to rotate said spindle, a

work chuck carried by said spindle, a slidable sleeve within said spindle to actuate said chuck to grip a work piece, yieldable means acting on said sleeve normally to hold said chuck in a gripping position, a iluid pressure mechanism including a piston and cylinder to actuate said sleeve and chuck to release the work piece, an ejector rod slidably mounted within said sleeve to eject a work piece from the chuck, a load and ilre mechanism including a spring, and a pivotally mounted lever actuated by movement of said sleeve to operate said load and tire mechanism and said ejector rod rapidly to eject a. work piece from said chuck.

' Y RAYMOND A. COLE.

CHARLES H. AMlDON.

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