US2254002A

US2254002A - Grinding machine

Info

Publication number: US2254002A
Application number: US277040A
Authority: US
Inventors: Decker Jacob; Ernst Hans
Original assignee: Cincinnati Grinders Inc
Current assignee: Cincinnati Grinders Inc
Priority date: 1939-06-02
Filing date: 1939-06-02
Publication date: 1941-08-26
Anticipated expiration: 1958-08-26

Description

Aug. 26, 1941;l J. DECKER ET AL 2,254,002

GRINDING MACHINE Filed June 2, 1959 6 Sheets-Sheet 1 movl/4L, ATTORNEY.

Aug. 26, 1941. J. DECKER ET'AL @BINDING MACHINE Filed June 2, 1939 6 Sheets-Sheet 2 INVENTOR. Jvcofc//cw #wy @m57 f ATTORNEY.

Aug. 26, 1941. J. DECKE ETAL 2,254,002

GRINDING MACHINE Filed June 2, 1959 6 Sheets-Sheet 3 @Jud/07ML.

ATTORNEY.

Aug. 26, 1941. J. DECKER ETAL 2,254,002

GRINDING MACHINE y Filed June 2, 1939 y 6 Sheets-Sheet 4 INVENTOR.

ATTORNEY.

Aug. 26, 1941.

A.1. DEc'zKR E-rAL y GRINDING MACHINE Filed June 2, 1939 6 Sheets-Sheet 5 ATTORNEY.

Aug. 26, 1941.- J. DECKER Em; 2,254,002

GRINDING MACHINE 1 Filed June 2, 1959 6 Sheets-Sheet 6 ATTORNEY.

Patented Aug. 26, 1941 GRINDING MACHINE Jacob Decker and Hans Emst, cincinnati, 01110 assignors to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation oi' Ohio Application June 2, 1939, Serial No. 277,040

19 Claims.

This invention relates to machine tools and l more particularly to improved transmission' and control mechanism for cylindrical grinding machines.

One of the objects of this invention is to provide improved ltable traversing mechanism and control means for a cylindrical grinding machine.

Another object of this invention is to provide improved means for interlocking the traversing mechanism and the infeed mechanism of a cylindrical grinding machine so that undesirable simultaneous operation for both mechanisms will be prevented.

A further object of this invention isl to provide an improved automatic infeed mechanism' for a cylindrical grinding machine which is sumciently flexible that the rapid traverse part of the infeed movement may be varied at will to reduce the time of the feeding movement.

Other objects and advantages of the present invention should be' readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming apart thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

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

Figure 1 is a front elevation of a grinding mav chine embodying the principles of this invention.

Figure 2 is a section through the machine shown in Figure 1 as viewed on the line 2-2 showing the infeeding mechanism for the wheel head.

Figure 3 is a section on theline 3-113 of Figure 1, showing the control lever in ya partially advanced position. y 1

Figure 4 is a section on 4the line 4-4 of Fig- Figure 5 is a detail elevational view partly in section to show the adjusting mechanism for the variable stop of the infeed control lever.

Figure 6 is a detail section of the rapid traverse infeed stop.

Figure 7 is al detail section through the endo! the reverse valve.

Figure 8 is a diagrammatic view of the hydraulic control circuit of the table traversing mechanism. 4 1

Figure 9 is a diagram of the hydraulic control circuit for the infeed mechanism.

25 wheel. l vided with depending brackets 28,-which support Figure 10 is a detail view of the yieldable stop forthe table traverse control lever.

Referring to Figures 1 and 2 of the drawings the reference numeral I0`indicatesthe bed or 5 main support of the grinding )machine upon the top of which is formed, as shown in Figure 2, a flat guideway Il and a V-guideway I2 Ifor supporting and guiding the work table I3. This table is provided with a conventional headstock,

l0 indicated generally by the reference numeral I4,

l5 manually controlled by the levers 20 and 2l shown in lFigure l through the usual conventional means, is also adapted t be hydraulically -retracted by a piston 22, vslidably mounted in a cylinder 23, through a centrally pivoted lever 24.

A grinding weel 25 is rotatably journaled on a wheelhead 26 which is guided Aon the bed for movement toward and from the work. The head 26 carries a prime mover 21 which is belt-connected for effecting rotation of the grinding Referring to Figure 8, the table I3 is-proa cylinder 29 for movement with the table. A piston 30 is contained within the cylinder and connected by piston rods 3i and 32 to fixed aprons 30 mounted on opposite ends of the bed in a conventional manner.

Thus, with the piston rod and piston iixed, the

admission of. hydraulic pressure `to opposite ends of the cylinder is effected 'through the piston 'rods which are made hollow and provided with cross bores 33 adjacent opposite sides of the piston.

The depending brackets 28a1so carry a rack 34 which serves as means for driving the table manually through the hand wheel 35. This hand-wheel is 'attached to the end f a pinion 36 which meshes with a spur gear 31, the spur gear having a co-axial pinion 38 which drives' the rack through an intermediate idler 39. In

order to prevent rotation of the hand wheel during power` actuation of the slide, a piston 40 slidably mounted in a cylinder 4I is axiallyv aligned with the pinion 33 for shifting the sametovthe left, as viewed in Figure 8, out of engagement with the idler gear 39.

control valve which has'a nxed sleeve 33 and a rotatable plunger 44. This plunger has various control portions throughout its length, and to facilitate understanding of the operation of this valve, a series of sections through the valve are shown in Figure 8 and indicated by the reference numerals 45 to 52 inclusive, it being understood that 'the outside portion is all part of the fixed sleeve and that the center portion in each section is all part of the valve `plunger and integral with the lever 42 whereby when the lever 42 is rotated counterclockwise as viewed in Figure 8 to its run position the center portion of each of the sections will be rotated through the same angle.- l

The opposite ends of the table motor are connected by

channels

53 and 54 to ports 55 and 56 ofthe start and stop control valve, the ports being shown in sections 45 and 46 of this valve. These sections also have ports 51 and 58 which are connected to the pressure supply line 59.

This line is supplied with fluid pressure by a pump 66, which has an intake 6| through which iiuld is withdrawn from a reservoir 62. It will be noted that in the stop position of this valve that both ports 55 and 56 are connected to the pump whereby pump pressure will exist in opposite ends of the cylinder 29 maintaining the same full of oil, thereby preventing admission of air to the system, 'but at the same time not interfering with manual traverse of the table by the wheel 35 since the oil in one end of the cylinder will be bypassed through the valve into the other end whenever the hand wheel is rotated.

When the lever 42 is thrown to its running position .the arcuate groovesA 63 and 64 will connect ports 55 and 56 to ports 65 and 66 respec tively and therebythrough channels 61 and 66 to

ports

69 and 16 of a reversing valve, indicated generally by the reference numeral 1|.

The reversing valve has a plunger 12 which ls power shifted from one end of the valve housing to the other by hydraulic means, which is controlled by a pilot .va1ve. indicated generallyA by the reference numeral 13. 'Ihe pilot valve has a plunger 14 which is mechanically connected by a crank 15 to the trip rod 16, this rod terminating in the trip lever 11 adjacent the side of the table as indicated in Figure 1.

Since the plunger 12 of the reversing valve has only two positions, the pressure port 16 of this valve will be connected at all times to either port 69 or 10 by means of annular grooves 19 and 66 respectively.

With the plunger 12 in the position shown,y

ports

18 and 69 are interconnected, and iluid pressure will flow through channel 61, port 65, groove 63, port 55 and channel 53 to the left end of cylinder 29, causing movement of the table I3 toward the left. Fluid from the other end of the cylinder will return through channel 54, port 56, groove 64, portl 66, channel 66 to port 16 of the reversing valve. 'Ihe latter port is interconnected by the annular groove 66 to exhaust port 6|. Should the plunger 12 be shifted upward as viewed in Figure 8 to its other position the pressure port 16 would be connected to port 16. and port 69 would be connected to the lexhaust port 62.

The rate of table traverse is controlled by throttling the exhaust fluid from the table motor rather than throttling the inow as is done in many cases. The traverse rate throttle valve is indicated by the reference numeral 63. Means are provided in the pilot valve for alternately connectingl the exhaust ports 6| and 62 of the reverse valve with the throttle valve 63 in accordance with the direction of table movement, so that one throttle valve will serve to control the rate in both directions.

This is accomplished by connecting ports 6| and62 to \ports 64-and 65 of the pilot valve by means of channels 66 and 81 respectively, and providing annular grooves 66 and 69 on the pilot valve plunger for alternately connecting ports 64 and 65 to port 96. 'Ihe latter port is connected by channel 9| to the intake port 92 of the throttle valve 83. This valve has an exhaust port 93 which is connected to the return line 94 that conveys the iluid back to the reservoir 62. A low pressure relief valve 95 is serially connected in the channel 94 for maintaining the system full oi oil.

Asthe table nears the 'end of its stroke. a dog 96 suitably positioned on the table starts rotation of the trip lever 11 and thereby through the mechanical .linkage previously explained starts longitudinal movement of the pilot valve plunger 14. :The pilot valve has a pressure port 91, and 'a pair of ports 98 and 99 which are connected to opposite ends .of .the reversing valve for alternately delivering pressure thereto to effect power shifting of the plunger 12. Attention is vinvited to the fact that the pilot valve plunger has a spool |66 which is larger in diameter than adjacent spools |6| and |62. whereby afterthe spool |66 passes pressure port 91 the admittance of fluid pressure behind the spool v|66 will complete the shifting of the plunger 14 due to the diierence in pressure on the opposing ends of adjacent spools.

The spool |66 reciprocates in the enlarged bore |63 and the length of this bore determines the length oi movement of the plunger 14. The pilot valve plunger is thus self-actuating after it passes amid-position.

With the pilot valve plunger 14 in the position shown in Figure 6 in which the pressure port 61 is, connected to port 96, the nuid has passed through channel |64, the lower end |65 of check valve |66, to port |61 of a tarry valve |66. This valve has a rotatably adjustable plunger |69 in the periphery of which is cut a V-shaped groove ||6 for varying the resistance of port |61 and thereby the rate of Ilow through the valve to port This port is connected by channel ||2 to annular groove ||3 formed in the sleeve of the reversing valve. This groove communicates with I two spaced ports ||4 and ||5.

The channel ||2 has a' branch line ||6 which is connected to the upper end ||1 of the check valve |66 whereby upon upward shifting of the reverse valve plunger 12, the returning iluid will build up pressure in channels ||2 and ||6 due to the resistance of the. tarry valve and shift the plunger ||6 of the check valve against the resistance of spring ||9 and thereby uncover the exhaust port |26. Since this port is connected to the return channel 94 the fluid exhausting from the reversing valve will be returned to reservoir.

The iiuid passing through this valve continues to the width of ports m and m, so that upon movement of the plunger from one extreme position to the other, the spools |33 will completely close ports ||4 and |30 in the middle of the stroke of the plunger. AA cross bore |34 is drilled in the bottom of the groove |32 to intersect a longitudinal bore |35.

'I'he manner of operation is as follows:

A table dog such as 96 rotates the trip lever 11 and thereby movesthe pilot valve plunger 14 toward its mid-position. The tapered spool |42 on the pilot valve plunger gradually closes port 9i), therebyrestricting the exhaust iiow from the table cylinder 29 which results in deceleration of its mid-position the port 90 will be completely closed and the table movement should cease. During this same time the spool has moved to a central position with respect to the pressure port 91. Although the momentum of the parts will no doubt be sumcient to carry the pilot valve plunger slightly beyond its midposition sovthat the hydraulic pressure at port 91 may complete i vautomatic reversal could not be completed. In

order to insure against such a condition happening the opposite ends of the table cylinder are connectedv by bleeder pipes |43 and |44 to ports |45 and |46 respectively of the pilot valve. 'I'he pilot valve plunger is provided with an annular groove |41 in which is drilled a cross bore |48 intercommunicating with an axial bore |49. The axial bore |49 has free communication with the atmosphere whereby uid passing through these interdrilled passages may freely exhaust to reservoir.

When the pilot valve plunger reaches its midposition the ports |45 and |46 are both in communication with the groove* |41 although each. port is about half closed. This permits the iluid in that end of the cylinder which is not conthe table. When the pilot valve plunger reaches channel to the cylinder 4|.

nected to pressure to bleed to reservoir suillby thl'Oush the tarry valve |20 to the annular 75 groove |29 of the reversing valve. Due to the high resistance of port |3| the iluid will ow through port |30 and annular groove |32 in the reversing -valve plunger to the ball check |38 which will open under pressure, thereby permitting the ilu'id to continue through passage l|39 to space |4|.` The pressure acting in this space will cause upward movement of the reversing valve plunger 12 at a rather fast rate, which will be reduced as ports |30 and ||4 close;

Movement through the midposition will be sustained by iluid' entering port |3| and escaping through port ||5. After the plunger 12 passes the midposition, port |30 will gradually open again to increase the rate of movement of the plunger. At the same time the tapered spool |50 will gradually open the pressure port 18 to start the return movement of the table at a gradually accelerated rate.

Thus, the pilot valve determines the deceleration of the table to stop; the time of movement of the reverse valve plunger to its mid-position determines the length of tarry of the table; and the rate of movement of the reverse valve plunger from its midposition to its end position determines the rate of acceleration of the table in its new direction.

The manner of reversing end of its stroke is the same but this time the pilot valve plunger will be moving upwardv as viewed in Figure 8 and when the pressure port 91 is connected to port 98 the fluid will ow through the space |05 of the check'valve |06 andl the tarry valve |08 to the upper end of the reversing valve starting the plunger 12 on its .downward movement. Fluid from the lower end piston to disconnect the hand wheel 35 and, by

referring to section' 50 of the start and stop control valve, it will be noted that the plunger 44 is provided with an arcuate groove |52 which will be positioned to interconnect pressure port |53 to` port |54, the latter being connected by Thus, whenever the valve plunger 44 is rotated counterclockwise to a running position, pressure is connected to the cylinder 4| to render the hand wheel 35-inoperative. When the plunger 44 is returned to a stop position the groove |52 will interconnect port |54 to an exhaust port |55 whereby the iiuid in cylinder 4| may return to reservoir and permit operative engagement of the hand wheel 35 with the table rack 34.

l Means Yhave |been provided for automatically feeding .the grinding wheel toward the work at the end of each stroke of the table comprising a pick feed wheel |56, and a pick feed pawl |51 pivotally supported on the end of an oscillatable lever |56. This lever has gear teeth |59 on the periphery of its hub intermeshing with gearteeth |60 formed on the end 'of an oscillatable lever |6| that is pivotally supported at |62. A crank |63 operatively connected t0 the lever |6| has a roller |64 joumaled in the end thereof for engagement by a contoured surface |65 formed on the periphery of a piston |66. The piston is reciprocably mounted inA a cylinder |61 which the table at the other- 99 and 98 respectively of the-pilot valve whereby when these ports are alternately connected to pressure upon shifting of the pilot valve plunger, the piston |66 will |be shifted first to one end of its cylinder and then to the other end ofy the cylinder. The contoured surface |65 has a peak |80 midway of che piston whereby upon movement of the piston from one end of its cylinder to the other, the crank |63 will be oscillated, thereby causing the pick feed pawl |51 to be ratcheted in one direction and caused to move the pick feed wheel during movement in the opposite direction.

'Ihe lead screw |92 is threaded in a nut |93 which is fixed with the cross slide 26. The rear end of the lead screw is provided with a piston |84 which is slidably mounted in a cylinder |95 which is attached to the frame |0 of the machine. It will now be evident that the pick feed wheel is operatively connected to cause rotation of the feed screw |92 and thereby effect small movements of the grinding wheel toward the work. Return movement of the grinding wheel is effected by withdrawing the plunger |83 and rotating the hand wheel |82 in an Opposite direction. For purposes of rapidly withdrawing the grinding wheel an additional distance to facilitate work loading operations, a sourceof uid pressure may be connected to cylinder |95 whereby thepiston will directly pull the slide to a return position or on the other hand advance the slide to bring the grinding wheel adjacent the periphery of the work; The control mechanism for this hydraulic operation constitutes part of the control mechanism for effecting automatic infeed cycles of the grinding wheel without table traverse', and therefore, will be described in connection therewith, reference now being had to Figure 9.

The opposite ends of the cylinder |85 are connected by channels |86 and |91 to annular grooves |98 and |98l formed in the valve casing prising an axially movablesleeve reciprocably mounted in a bore 202 of the casing 200, and a valve plunger 203 reciprocably mounted within the sleeve. The plunger 203 has a feed back connection through the pivoted lever 204 from the lead screw |92. One end of the lever 204 is in position to be engaged by a shoulder 205 Th'is casing contains a servo-valve com-.

has a port |68 at one end connected by channel i formed on the lead screw. this position against a stop 3|3 by means of a spring 206 which is interposed between a shoulder on the plunger 203 and a xed plate 201. A second spring 208 is interposed between the plate 201 and the end of the sleeve 20| which thereby holds the sleeve into engagement with a bell crank 209, one end` of the bell crank carrying a roller 2|0 which is held into contact with an internal cam surface 2| formed on the rotatable member 2|2.

The member 2|2 and associated cam are ro -tatable by the lever 2|3 in a clockwise direction as viewed in Figure l to cause counterclockwise of the sleeve 20| to the right as viewed in Figure rotation ofthe bell crank, 209 and a shifting 9 to connect the pressure groove 2|4 to the groove |99 through the radial ports 2|5 in the sleeve. the annular groove 2|6 in the Vplunger 203 and theradial port 2|1 in the sleeve. This will result in fluid pressure flowing through channel |91 to one end of the cylinder |85, causing the piston |94 to advance the screw |92 and connected wheel slide toward the work at a fast rate. After the piston |84 has advanced to the -piston shown in Figure 9 and taken up the lost motion between lshoulder 205 and lever 204, the latter will be rotated to cause movement of the valve plunger 203 toward the right, thereby ciosing the radial ports 2|5 inthe sleeve 20|. The returning fluid from cylinder |95 flows through channel |86, annular groove |88, radial porto 2|8 insleeve 20|, annular groove 2|9 in plunger 203, radial ports 220 in sleeve 20| to the annular groove 22| in the valve block which is connected to the return'channel 222. When the sleeve 20| l is shifted in the other direction to connect the pressure groove 2|4 to groove |98, and thereby to the left end of the cylinder |95, the exhaust fluid will return through channel |91, groove |89, radial ports 2|1 in sleeve 20|, annular .groove 2|6 in plunger 203 and radial ports 223 in sleeve 20| .to the exhaust line 222.

Attention is invited to the fact that the rotatable member 2|2 is connected by pinion teeth 224 and rack teeth 225 to a piston rod 226 which is integral with a piston 221 slidably mounted Ain a cylinder' 228. When the piston 221 is in the extreme upper end oflcylinder 228 which is the 'normal starting position, the lower end of the cylinder is full of uid and due to the position of various valve mechanisms to be described later, this fluid is impounded in the cylinder which serves as means to prevent inadvertent rotation of the handle 2|3. Valve means have, therefore, been provided for operation by the lever 2|3 to connect the lower end of the cyl- -inder to reservoir before the lever 2|3 can be rotated. This is accomplished by pivotally connecting the lever 2|3 by a pin 229 to the member 2|2, andadditionally connecting the lever 2|3 by a link 230 to a by-pass valve plunger 23| whereby the levermust be pulled out, or

rotated about the pin 229, to shift the plunger 23| into a uid by-passing position before the lever can be rotated -to eil'ect actuation of the cam 2| I.` A spring 232 is interposed between a shoulder 233 on' the valve plunger and a ilxed plate 234 for normally holding lthe parts inthe position'shown in Figures 3 and 9.

When' the by-pass valve plunger 23| is inthe position shown, a flrst annular Agroove 235 connects port 236, which receives fluid pressure from pump 60 through channel 231, to the upper port 238 of cylinder 228 through port 238 and The lever is held in 2,254,002 In addition, the valve 268 has a port 215 which channel 248. A second annular groove 24| in the plunger connects the lower end of cylinder 223 to reservoir through port 242, channel ,243, port 244, groove 24|, port 245, channel 248 and port 241 of reversing valve 248. This valve has a plunger 249 which is normally held in the position shown by the spring 258 whereby an annular groove 25| in the plunger will interconneet port 241 to port 252. The latter port is connected by channel 253 Ito port 254 of an infeed rate throttle valve 255. This valve has ,a rotatable plunger 256 in which is cut a V-shaped resistance groove 251 through which fluid will ilow to the return channel 258.

The resistance of this throttle valve is sufilcient, however, to prevent escape of fluid from the lower end of cylinder 228 under the normal pressure which an operator would exert on the lever` 2 I3, and thus impoundedciluid acts as means to prevent inadvertent rotation of the lever 2|3. The by-pass valve has another port 259 which is connected to the reservoir line 222 whereby when the lever 2|3 pulls the plunger 23| outward, this port registers with an annular groove-268 formed in the plunger. A cross bore 26| formed in this groove intersectsian axial bore '262 which establishes communication with a second cross bore 263 formed in the annular groove 24|. Thus, when the plunger is pulled out,

ports

239 and 244 which are connected respectively to opposite ends of the cylinder 228- are directly connected to reservoir through the interdrilling inv the plunger, thereby breaking the hydraulic lock on piston 221'.

The operator may now rotate the cam 2|| by lever 2I3 to open the servo-valve and effect the rapid movement of piston |94 in the manner explained. vThe manual movement of lever 2|3.

is maintained until piston 221 has been vmoved downward a suftlcient distance to uncover port 238. The operator then releases -the lever 2|3 whereupon the spring 232 repositions the by-pass valve to eiect interconnection of the pressure port 238 with port 239 whereby fluid pressure will continue the downward movement of thev is connected by channel 218 to a pressure operated switch 211 and in the normal position of the plungerfr281 -the port 215 .is connected byr annular groove 212 to the exhaust port 213. But upon upward movement of the plunger 281 the iluid pressure entering port 265 raises the plunger a sufilcient distance to uncover port 215 whereby the pressure fluid will close thevpressure operated switch 211 and start rotation of the headstock motor I5, which drives the face plate I8. Attention is invited to the fact that the port 218 leading from the tailstock operating cylinder is connected to the reservoir port 213 before the pressure port 265 is connected to port 215 so as to insure that the tailstock center has engaged the work before the headstock motor starts,r otation thereof. Inorder to insure a little time delay between the happening of these two events a choke coil 218 is utilized to connectthe upper end of thevalve to the ex- .haust line 222. When theservo-valve is shifted in the other direction to connect the annular groove |99 to the exhaust port 223, a spring 219 assists in repositioning the plunger 261. It Will be noted that in the downward movement of the plunger that the headstock pressure switch is opened before the tailstock center is retracted.

It will further be noted that the channel 218 has been indicated as provided with an extension 218' which canbe coupled withA conventional coolant or other .controls notshown so that the same may be actuated by the .hydraulic medium concurrently with the operation `of the headstock switch. y

As the piston 221 which causes operation of the servo-valve completes its downward movement, a pin 28.8 carried by the piston rod 228 rotates lever 28| which is connected to a. pilot valve plunger 282 and shifts the plunger relative to a pressure -port 283 in `the valve houspiston 221 andl thereby continue rotation of the connected by a channel 284 to port 285 of `a headstock and tailstock control valve 288. This initially shifted to the right as viewed in Figure 9 to connect the pressure source of annularv groove |99 to cause infeeding movement of the grinding wheel that the plunger 281 of valve 288 will be forced upward 'under hydraulic pressure. This valve has a pressure port 288 which is nor mally connected by annular groove 288 to port 218'4 which has a channel 21| leading to tailstock operating cylinder 23. Pressure in this cylinder holds the tailstock center I9 in a retracted posiy tion. When the plunger 281 is forced upward ing 284.

The' plunger 282 has an enlarged spool 285 which is movable relative to the pressure port 283 whereby after the spool passes the pressure port the incoming pressure uid produces a pressure differential action which completes Ithe shifting movement of the plunger. When theI plunger v is in the position shown in Figure 9 an exhaust port 286 is connected to port 281 by annular groove 288 in the plunger'whereby the end of an interlock cylinder 289 containing an interlock plunger 298 is connected to reservoir through channel 29| whichis connected to the port 281. 'I'he interlock plunger 298 engages a groove 29| formed in the start and stop valve control plunger.44,'and, in the position shown, prevents ro means that when the servo-valve sleeve 28| is the port 218 is disconnected from pressure and connected by the annular groove 212 to an exf haust port 213. This permits the oil in cylinder 23 to be exhausted to reservoir by the pressure of a spring 214 which continuously urges the tation ofv this plunger; to a table traversingposition by the lever 42. The spring 292 holdsthe interlock plunger in the position shown.

When the pilot valve plunger is shifted upward the pressure from port 283 is connected by the annular groove 288 to por/t281, thereby effecting withdrawal of theplunger 298. This -permits the operator to rotate the lever 42 into a running position to effect a traversing movement ofthe table I3y by power if such movement is desired.

'I'he upward shifting of the pilot valve plunger also eil'ects interconnection of

ports

293 and 294 by annular groove 295. The port 293 is con nected by a channel 296 to'port 291 of a tarry valve 298. This valve has a pressure port 289 and a rotatably adjustable plunger 388 which has a. V-shaped groove 38| cut in its periphery ifor 6 varying the -rate of ilow from port 299 to port 291. .p

The port 294 of the pilot valve is connected by a channel 302 to port 303 located in the lower end of theA reversing valve housing whereby fluid pressure will slowly iow through the throttle valve '298 to the reversing valve housing, causing a slow upward movement of the reversing valve plunger 249.

When the annular groove 25|, in the reversing valve plunger 249 has moved suiiiciently to inter- .connect pressure port 304 .to port 241, pressure uid will then iiow to the lower end of cylinder 228 through interconnected ports 245- and 244 o-f the bY-passvalve and channel 243. 'Ihe piston 2 21'will now'start to move upward, rotating the `control cam of the servo-valve in the opposite direction to cause retraction of the wheel head. Although port 238 atl the upper end of cylinder 228 is still connected to pressure 'the piston 221 will still move upward due to the fact that Ithe area of the lower end of the piston 221 is greater than the area of the upper end. When the piston closes port 239 it traps fluid in the upper end of the cylinder. However, a port 305 located inthe cylinder is now in communication with a port 306 contained in the piston. The port 306 is connected by an interdrilled passage 301 to the upper face of the piston 221 whereby the entrapped uid may still escape to the reservoir line 94 whereby the piston may continue its movement to return control lever 2|3 to its starting position. i

As rthe piston 221 completes its upward movement the pin 280 carried by the piston rod 226 rotates the pilot valve trip lever 28| in a clockwise direction, thereby shifting the pilot valve plunger 282 downward into the position shown. 1

This reconnects the interlock cylinder 289 with reservoir whereby the spring 292 may reposition the interlock plunger 290 into engagement with the start and stop valve control plunger 44. It also connects port 294, leading from the lower end. of th reversing valve housing, to reservoir through n axial passage 308 in the pilot valve, which has cross bores 309 and 3|0 com- 'municating with annular grooves 295 and 3H respectively. .The annular groove 3|| is moved into communication with exhaust port 3|2 when the' plunger 282 hasl completed its downward shifting movement. This permits the reversing valve plunger'249 to be returned by the spring 250, thereby disconnecting the pressure port 304 from port 241 so that pressure iiuid no longer ows to thelower end of cylinder 228, and reestablishes the connection between ports 241 and 252 whereby thelower end of cylinder 226 is connected through the throttle valve 256 preparatory to control the rate of the `next inrfeeding movement.

Attention is invited to the fact that at any cause full retraction of the wheel head. It is to be remembered that although the wheel head has a total movement of approximately one inch the greater part of this movement is eiected lata rapid traverse rate because .the servo-valve is only eiective during the last 31," movement. The servo-valve plunger 203 is urged by a spring 206 in one direction and a stop 3|3 is provided for hunting this movement. .'I'herefore, when the parts areinla starting position the pressure port 2|5 is connected to the annular groove |98 and thereby to the cylinder |95 because the stop 3|3 limits the plunger 2|3 from shifting a. suiilcient distance to close the pressure port 2 5.

This means that after the slide has returned alf" and the leverI 204 has engaged the stop 3|3, the wheelhead continues its retraction autogiatically until the piston |94 engages the end f its cylinder. The same thing is true on the advancing movement in that after the cam has been rotated to eEect suilicient displacement oi the sleeve 20| to connect the pressurel port 2|6 to the annular 'groove |99 the wheel head slide moves in at a rapid traverse rate until the shoulder 205 on the lead screw picks up the lever 204 and thereby establishes the feed back connection to the servo-valve, after which the rate oi movement is determined by the infeed throttle valve. l

It w-ill now be evident that the control cam 2|| can only control the last 512" of the total inward movement of the wheel head. l

The operator pulls out the lever 2|3 and rotates it sufliciently to start the wheel head moving in. If the operator stops rotation of the lever 2 I3 as soon asthe wheel head .starts to move, the wheel head will continue its inward movement for Valmost an inch automatically because the cooperating parts of the servo-.valve have been positioned to connect the iiuid pressure to the rear end of thepcylinder and nothing can occur to stop this flow until the shoulder 205 on the lead screw picks up the feed back lever 204 and repositions the plunger 203. At this time the piston 221 will have moved a sumcient distance to uncover the port 238 and if the operator releases the lever 2|3, the spring 232 will reposition the by-pass valve plunger to connect pressure to port 238 and thereby continue the movement of the wheel head through its last nl," of movement at a slow grinding rate. .f

It is well known to those skilled in the art that the-amount of stock left on a work piece to be ground oi to produce the final size of the work `varies considerably which is ,in part determined by the number and character of the preceding operations upon the work before it reaches the grinding machine. It should, therefore, be evident that if; only .010 stock were left in the work and the machine was provided with a iixed movement of 31g" for automatic infeed that considerable time time during automatic ini'eeding oi the grinding wheel, the operator may, at will, interrupt the infeed cycle and eiect immediate retraction of the grinding wheel by pulling out the lever 2 I3, which will immediately interconnect the upper and] lower ends of the cylinder 228. Rotation of the lever back to its starting position will manually return the piston 221 to its starting position due to the mechanical interconnection between the lever 2 3 andthe piston.

This movement will simultaneously return the control cam 2H so that the servo-valve sleeve would be wasted and the production of the machine seriously decreased,

Provision has therefore, been made whereby the operator may determine the limit of therapid` traverse movement or in other words, increase the 20| will be positioned sumciently-,to the left to Q5 length of the rapid traverse movement so that when the slow feeding movement becomes effective the grinding wheel will be approximateely in engagement with the work and no time will, therefore, be lost. y

'I'his is accomplished by providing an adjustable stop member for the control lever 2|3 and reference may now be had to Figures 3, 5 and 6.

be held at the forward end of its cylinder.

gaging a worm wheel 32| lwhich is fastened to the plate. The worm 320 is pinned to a shaft 322 which is journaled in the housing 323 and provided with an operating knob324. The plate 3I6 is provided with graduations 325 which are movable with respect to a xed arrow 326. 'Ihe stop` 3I4 is normally held in a projected position by a spring pressed ball 321 whereby the end of the stop lies in the plane of rotation of, the lever 213 when the same has been pulled out by the operator. By suitably marking the graduations 325 to indicate the amount of stockto be removed by the grinding wheel, the stop 3I4 may be positioned to limit the movement of the lever 2l3 so that vwhen the operator rotates the lever into engagement with the stop, contact will just be established between. the grinding wheel and the work. This means that the piston 221 may be moved at a rapid traverse rate a considerable distance beyond the port 238 before the slow ini'eeding movement starts. It will be obvious that as soon as the operator releases the lever 2 I3 after engagement with the stop 3I4 the lever will move laterally out of engagement with the stop, thus upward movement of the piston 221 and rotation of theservo-valve control cam to its starting position. 'I'his will cause immediate retraction of the wheel head.

'Ihe yieldable stop comprises a stop member 333 which ispivotally supported on a fixed pin, 334, and held against clockwise rotation by a spring 335 bya stop pin 336. The rotatable plunger 44 carries a cross pin 331 which abuts the nose 338 of the stop 333 when rotated to a stop position. Further movement will rotate the clearing the same so that the remainder of the movement may be completed. The stop has been pivotally mounted so that in case the lever isv pulled out by the operator at any time to return the parts the lever will simply rotate the stop out of the path of the lever during its return movement. traverse grinding the stop is set at zero so that the lever 2|3 may rotate a full stroke and thus bring the wheel head in the full distance allowed by cylinder |95. In addition, the tarry valve 298 is completely closed so that the reversing valve will not, be operated whereby the piston |94 will The in and out movement of the grinding wheel will then be effected by the pick feed mechanism through rotation of the screw |92. Since the pilot valve 283 will now be in a position to connect pressure port 283 to port 281 the plunger 290 will be held in a retracted position so as not to interfere with the actuation of the start and stop control valve.

A yieldable stop shown in Figure l0 has been provided for determining the stop position of the start and stop control lever 42 whereby in an emergency during traverse grinding the operator may throw the lever 42 to it`s-stop" position to stop the table and by applying su'lcient pressure the lever may continue its rotation beyond the stop position to effect retraction of the wheel head by the piston '|94. This is accomplished by providing the plunger 44 with a cross bore 329 as shown in section 52 of the valve. This lsection is provided with a pressure port 330 which may be connected by the cross bore to port 33 I, the latter being connected by achannel 332 to channel 382 which interconnects port 294A of the pilotvalve with port 303 of the reversing valve. This means that pressure ilidwill iiow to port 303 of the reversing valve and shift the reversing valve .plunger 249 upward to connect the pressure port 384 to port 241 and thereby, through the b'y-pass valve to the lowerv end of cylinder' 228, causing When the machine is utilized for yieldable stop in a counter-clockwise direction. Upon release of lever 42 the parts will return to a stop position. b

In the hydraulic diagrams, the pump supply channel is indicated throughout by the reference numeral 59, and the reservoir return channel by the number 94. The channel 59 has a suitable pressure relief valve 339 connected thereto as shown -in Figure 8 to protect the system. There is also shown a control valve 340 which may be utilized for controlling power operation of a cool-r ward, the coolant or other devices controllable by pressure in the 'conduit 345 derive this pressure from the main pressure conduit system 59 and the connection between 34| and 345 is shut off by spool portion 346 of said valve.

There has thus been provided an improved grinding machine having novel traversing mechanism for the table and improved mechanism for in-feeding the grindingl wheel, together with suitable interlocks between the two mechanisms valve therefor, a rotatable cam for actuating said valve, a piston actuator for said cam, means for hydraulically locking said piston against movement, a manual control lever, means operable by said lever upon movement in one direction for releasing the locking fluid, means opery able by said lever upon movementin a second direction to effect simultaneouslyimovement of the piston and cam to initiate movement of said slide, and means controlled by the lever for connecting iluid pressure to said piston after a predetermined movement thereof whereby said piston will automatically continue actuation of the motor. v

2. In a grinding machine having a grinding vwheel support and a work support, the combination of power `operable means for moving one of said supports toward and from the other support including a fluid operable motor connected for actuation of onevoi said supports, a servocontrol valve for the motor, a rotatable cam for actuating said servo-valve, a piston actuator for said cam, means for hydraulically locking said piston against movement, a manual control lever,

l means operable by saidlever upon movement in one direction for releasing the locking. uid, means operable by said lever upon movement in -automatically reversing its direction of movement, and means to produce a delay in effecting said reversal whereby a dwell in the movement of the slide will be created to permit the grinding wheelto finish the work to size.

3. In a grinding machine having ak grinding.

wheel support and a work support, the combination of power operable means for effecting movement of one of said supports toward and from the other including a control cam for said power.

means, a fluid operable piston operatively connected for effecting rotation of said cam, a hydraulic controlf circuit for said piston including a ysource of pressure and a reversing valve, a

throttle valve, means in the reversing valve fory directly connecting the source of pressure with one side of'said piston and serially connecting said source of pressure through said throttle valve to the other side of said piston whereby said piston will move at a slow rate in one direction to effect, advancing movement of said support and at a rapid traverse rate to eifect return movement of said support, means hydraulically locking said piston at the completion of the return stroke, a starting lever, and means operable by said lever for releasing the locking fluid to initiate the next cycle.

4. In a grinding machine having a grinding wheel support and a work support, the combination of power operable means for feeding one of said supports toward and from the other support including a rotatable element operatively connected for controlling said movement in accordance with the rate of movement of vsaid element, a fluid operable piston for power moving said element, a cylinder containing said piston, said cylinder having a first port for receiving uid Ito cause one direction of movement of said piston and a second port for receiving fluid for causing a return movement of said piston, said first port being positioned so as to be closed by said piston when in a starting position, manually operable means for moving said piston a sufficient distance to uncover said rst port and simultaneously effect a positioning movement of said support, and additional means operable by said manual control means to connect pressure to the first-named port to continue the movement under control of said element.

5, In a grinding machine having a grinding wheel support and a work support, the combination of means for effecting movement of one of said supports toward and from the other including a prime mover, a movable rate control means having a stop position, a manually operable control lever for shifting said rate control means to cause actuation of the movable support, power operable means for continuing the movement of said rate control means, said power operable means including a piston. a cylinder, a piston rod connecting the piston for movement of said rate control means, a source of pressure for actuating said piston, said piston having a hydraulically inoperative position, and means controlled by the lever for vmoving said piston to a hydraulically operative position and sequentially connecting fluid pressure to the cylinder to continue movement of the piston.

6. In a machine tool having a grinding wheel 'support and a work support, the combination of lpower operable mechanism for effecting movevment of one of said supports towardthe other support including a hydraulic control circuit, a manually operable control lever having a stcp po- ,sitionin which the control circuit is hydraulically locked, means to shift said lever in one-direction to unlock said circuit, means responsiver to move- Ament of the lever in the second direction to efvsupport including a hydraulic control circuit, a

rection 'to unlock said circuit, means responsive to movement of the lever in a second direction to effect a rapid positioning movement of the supl port, an adjustable stop for said lever for determining the length of said positioning movement, and graduated means for micrometricall setting said stop. f

8. In a grinding machine having a lgrinding wheel support and a work support, the combination of power operable means for effecting relative movement between said supports, control means for said power operable meansA including a lever rotatable in one plane for effecting'a rapid traverse movement of said support, a stop for said lever for determining the extent of said rapid traverse movement, said lever being shiftable into a second plane to clear said stop, means operable by the last-named movement of said lever to effect power rotation thereof in a second plane to produce a feeding movement of said support.

9. In a grinding machine having a grinding wheel support and a work support, the combination of a hydraulic operating circuit for traversing the'workI support including a start and stop control valve, a second hydraulic operating circuit for feeding the grinding wheel support toward and fromthe work support including a direction determining valve, an interlock plunger, means normally holding said plunger in engagement with the rst-named valve to prevent movement thereof from its stop position, and fluid operable means controlled by said direction def termining valve for withdrawing said interlock after the grinding wheel has completed its power movement toward the work support.

10. In a grinding machine having a grinding wheel support and a worksupport, the combination' of a fluid operable control circuit for, advancing said grinding wheel support toward the work support, said circuit having a reversing valve which is fluid shiftable to effect retraction of said support, a fluid operable control circuit for traversing said support including a control valve normally movable between a stop. position and a running position tocontrol lthe traversing movement of said work support, a control lever for said valve, a resilient stop for limiting movement of the lever when it. reaches a stop position, and means in the valve and responsive to movement of the lever beyond its stop position to connect uid pressure to said reversing valve whereby a continuous unidirectional movement of said control lever will stop the work support support.

11.In a grinding machine having a grinding wheel support and a work support, means forl controlling relative movement of said supports including a piston and cylinder mechanism providing a hydraulic motor, a source of hydraulic actuating medium, a servo-control mechanism for determining the rate and direction of iiow of the hydraulic medium with respect to the motor, said servo-mechanism including a pair of relatively adjustable parts, control means for determining the amount and direction of movement of one of said servo-parts, and a feed back mechanism including a lost motion connection between the hydraulic motor and the other oi said servo-elements whereby an initial rapid movement of the motor may be effected by shifting oi the first servo-element prior to the counteracting movement of the other element as eifected through said lost motion connection.

12. In a grinding machine having a grinding wheel support and a work support, means for controlling relative movementvof said supports including a 'piston carried by one of the supportsv and a containing cylinder for the piston carried by the other of said supports, a .source of hydraulic actuating medium, and means for controlling the activation ofthe piston and cylinder elements bythe hydraulic nmedium including a servo-mechanism having a rst element shift- .able for operatively coupling the hydraulic mey dium with the cylinder, a second element shiftable to counteract the movement of the first, a feed back from the hydraulic motor to said second element for determining the positioning thereof, said feed back including a lost motion,

connection permitting limited actuation of the motor without actuationvof the second element of theservo, a retractable tailstock carried by the work support, a rotatable headstock carried by the work support, means for activating said elements including hydraulic controls and hydraulic connections establishable by movement of the first servo-element prior to actuation of the lost motion feed-back @hereby the tailstock and headstock will be activated priorv to initiation ofthe servo-control of relative movement of the supports.-

13. In a grinding machine, the combination with a work support and a tool support, of means for controlling the relative movement of the supports including a hydraulic motor having a cylinder portion carried by one of the supports and a piston and piston rod operatively associated with the other of the supports and a hydraulic control circuit for operation of the motor including a source of hydraulic actuating medium and a servo-device intervening the source of medium and the motor, said servo-device including a first valve portion shiftable to couple the medium with the cylinder, a secondccounteractingI valve portion shiftable in opposition to the iirst, cam

means for eiecting shifting of the ilrst valve member, a'linkage including a lost motion device connecting the second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement ofthe hydraulic motor.

14. In a grinding machine, the combination with a work support and a tool support, of means for controlling the relative movement of the aupports including .a hydraulic motor having a cylinder portion carried by one oi' the supports' and a' piston and piston rod operatively associated 75` connecting the second valve member with the with the other of the supports and a hydraulic control circuit for operation of the motor including a source of hydraulic actuating medium and a servo-device intervening the source of medium and the motor, said servo-device including a iirst valve portion shiftable to couple the medium with the cylinder, a second counteracting valve portion shiftable in opposition to the iirst, cam means for effecting shifting yof the nrst valve member, a linkage including a lost motion device hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, a. nrst resilient means to reversely actuate the feed back servo-element, and means for hunting the extent of resultant actuation thereof.

15. In a grinding machine, the combination with a work support and a tool support, of means for controlling the relative movement oi' the supports including a hydraulic motor having a cylinder portion carried by one of the supports and a piston and piston rod operatively associated with the other of the supports and a hydraulic control circuit for operation of the motor including a source, of hydraulic actuating medium and a servo-device intervening the source of medium and the motor, said servo-device including a rst valve portion shiftable to couple the medium with the cylinder, a second counteracting valve portion shiftable in opposition to the first, cam means for effecting shifting of the ilrst valve member, a linkage including'a lost motion device connecting the second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, a first resilient means to reversely actuate the feed back servofor controlling the relative movement of the supports including a hydraulic motor having a cylinder portion carried by one* of the supports and a piston andpiston rod operatively associated with the other of the supports and a hydraulic control ci-rcuit for operation ci the motor including a source of hydraulic actuating medium and a. servo-device intervening the source of medium and the motor, said servo-device including a iirst valve portion Ashiftable to couple the medium with the cylinder, a second counteracting valve portion shiita-ble in opposition -to the iirst,

cam means for eifecting shifting of the ilrst valve l member, a linkage including a lost motion device connecting the second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, means for normally locking the cam against movement. and a control lever mounted for oscillation in one vdirection to eifect a release of the cam and for oscillation in an angularly related direction for eiecting rotation of the cam to actuate the valve member.

17. In a grinding machine, the combination with a work support and a tool support, of means for controlling the relative movement of the supports including a hydraulic motor having a cylinder portion carried by one of the supports and a piston and piston rod operatively associated with the other of the supports and a hydraulic control circuit for operation of the motor including a source of hydraulic actuating medium and a servo-device intervening the source of medium and the motor, said servo-device including a ilrst valve portion shiitable to couple the medium with the cylinder, a second counteracting valve portion shiftable in\opposition to the rst,

cam means for effecting shifting of the first valve member, a linkage including a lost motion device connecting the second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, means for normally locking the cam against movement, a control lever mounted for oscillation in-one direction to effect a release of the cam and for oscillation in an angularly related direction for effecting rotation of the cam to actuate the valve member, and a hydraulic motor coupled with the cam and energizable by one of said lever movements for effecting power actuation oi the cam.

18. In a grinding machine, the combination with a work support and a tool support, of means for controlling the relative movement of the supports including a hydraulic motor having a cylinder portion carried by one of the supports and a piston and piston rod operatively associated with the other of the supports and a hydraulic control circuit for operation oi the motor including a source of hydraulic actuating medium ancll a servo-device intervening the source of me- 4 dium and the motor, said servo-device including a first valve portion shiftable to couple the medium with the cylinder, a second counteracting valve portion shiftable in opposition to the first, cam means for effecting shifting of the iirst valve member, a linkage including a lost motion device connectingthe second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, means for normally locking the cam against movement, a control lever mounted for oscillation in one direction to eilect a release of the cam and for oscillation in an angularly related direction for effecting rotation of the cam to actuate the valve member, a hydraulic motor coupled with the cam and energizable by one of said lever movements for effecting power actuation of the cam, and means for adjustably determining the rate of poweractuation of said cam.

19. In a grinding machine, the combination with a work support and a tool support, oi means for controlling the relative movement of the supports including a hydraulic motor having a cylinder portion carried by one of the supports and a piston and piston rodoperatively associated with the other of the supports and a hydraulic control circuit for operation of the motor including a source of hydraulic actuating medium and a servo-device intervening the source oi' medium 'and the motor, said servo-device including a first valve portion shiftable to couple the medium with the cylinder, a second counteracting valve portion` shiftable in opposition to the first, cam means for effecting shifting of the ilrst valve member, a linkage including a lost motion device connecting the second valve member with the hydraulic motor to initiate feed back actuation of the servo-mechanism upon prescribed movement of the hydraulic motor, means for normally locking the cam against movement, a control lever mounted for oscillation in one direction to eilect a release of the cam and for oscillation in an angularly related direction for eiecting rotation of the cam to actuate the valve member, a hydraulic motor cou- '.pled with the cam and energizable by one of said lever movements for eiiecting power actuation of-the cam, means'for adjustably determining the rate of power actuation of said cam, trip operated means for effecting a reversal of the hydraulic support actuating motor, and additional means for effecting said reversal irrespective of the position of said trip operable means.

JACOB DECKER. HANS ERNST.