US2157946A - Infeed cycle control mechanism for grinding machines - Google Patents

Description

M y 1939- R. D. WORTENDYKE 5 5 INFEED CYCLE 'CONTROL MECHANISM FOR GRINDING MACHINES I Filed July 25, 1938 4 SheetsSheet 1 ATTORNEY.

May 9, 1939. WORTENDYKE 2,157,946

INFEED CYCLE CONTROL MECHANISM FOR GRINDING MACHINES Filed July 25, 1938 4 Sheets-Sheet 2 ATTORNEY.

May 9, 1939. R, D. WORTENDYKE 2,157,946

INFEED CYCLE CONTROL MECHANISM FOR GRINDING MACHINES Filed July 25, 19:58 4 Sheets-Sheet 5 ATTORNEY.

May 9, 1939. I R. WORTENDYKE 2,157,946

INFEED CYCLE CONTROL-MECHANISM FOR GRINDING MACHINES Filed July 25, 1938 4 Sheets-Sheet 4 g ATTORNEY.

Patented May 9, 1939 UNITED STATES INFEED CYCLE CONTROL MECHANISM FOR GRINDING MACHINES Raymond D. Wortendyke, Cincinnati, Ohio, as-

signor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application July 25,1938, Serial No. 221,051

. 14 Claims.

This invention relates to machine tools, and more particularly to improvements in grinding machines.

One of the objects of'this invention is to provide an improved automatic infeed mechanism for grinding machines.

Another object of this invention is to provide a mechanism of the character described which is relatively economical to construct'and operate.

A further object of this invention is to provide an infeed cycle control apparatus which may be built as a separate unit for application to new or existing grinding machines.

An additional object of this invention is to provide an automatic infeeding mechanism which will execute a complete cycle of operation including rapid traverse advance, variable feed, tarry and rapid return and stop.

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 illustrative of one embodiment thereof, but it will be understood that any modifications may be made in the specific structural details 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 plan view of a grinding machine in which this invention has been embodied.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is a section on the line 3-3 of Figure 2.

Figure 4 is a section on the line 4-4 of Figure 2.

Figure 5 is a section .on the line 5-5 of Figure 2.

Figure 6 is a section on the line 66 of Figure 2.

Figure 7 is a detail view of the hydraulically actuated limit switch for controlling rotation of the workhead. I

Figure 8 is a detail view of the workhead chuck operating cylinder.

Figure 9 is a diagrammatic view of the hydraulic control circuit showing the interconnection with thehydraulic elements shown in Figures 3, 4, 5, 6, 7 and 8.

Figure 10 is a diagram of' the hydraulic cycle control circuit.

As an example of a machine to which this invention is applicable, there is shown in Figure 1 of the drawings a grinding machine having a bed ID, a 'work support H, a grinding wheel l2, and a support I 3 for the grinding wheel which is 'oscillatably mounted on the bed for moving the grinding wheel toward and from the work support.

The oscillating movement of the grinding wheel support may be divided into two components, one of which is a rapid traverse movement effected by a hydraulic jack whereby the grinding wheel is moved from a work loading to a grinding position; and a feeding movement effected by a rotatable cam having the necessary contoured surface for completing the infeeding movement of the grinding wheel during a fixed angular rotation of the cam.

The machine structure thus far described cor responds in general to the machine shown in U. S. Patent 2,025,885.

This invention deals with means for efiecting an infeeding cycle of a grinding wheel and comprises, in general, a manual control lever, a power relay mechanism for reproducing the movements of the lever in the cam, and an automatic cycle control mechanism for effecting automatic power movement of the lever.

The grinding wheel is secured to the end of a spindle l5 which is journaled in the support l3. The support oscillates about an axis l6 located below the axis of the spindle in such a manner that counterclockwise motion of the support will move the grinding wheel toward the work piece and clockwise motion will move the grinding wheel away from the work piece. The hydraulic jack, which effects the initial or rapid traverse movement of the grinding wheel from its retracted or work loading position, comprises a piston l1 and a cylinder [8, the latter being formed integral with the grinding wheel support. A piston rod l9 projects through one end of the cylinder into engagement with one end of a plunger 20 which is reciprocably guided in a fixed part of the bed It]. The plunger has an anti-friction roller 20' which engages the periphery of a feed control cam.

Channels 2| and 22 are connected to opposite ends' of the cylinder l8, as shown in Figure 2, so that when fluid pressure is admitted to channel 2|, the pressure created in the upper end of the cylinder will cause counterclockwise motion of the grinding wheel, and when fluid pressure is admitted to channel 22, the opposite effect will be produced.

The actuating mechanism is so designed that it may be controlled by a single member, one oscillation of which will result in a complete to the right hand end of cylinder 50, causing.

' grinding cycle, beginning at the work loading po- 01' the grinding wheel and terminating at sitio the ame position. This common control comprises a lever 23, which, as shown in Figure 2, is flxed to the end of shaft 24 supported for rotation on antifrlction bearings 25 carried by the bed of the machine.

One end of shaft 24 is provided with a head '26 in which is mounted a crank pin 21 projecting into a radial slot 28 formed in the sleeve 29 of a servo-valve indicated generally by the reference numeral". Theservo-valve has a housing 3| which is held against rotation by a set screw 32 threaded in the'bed of the machine. A co-axial main shaft 33 has a portion 34 which through the center of the servo-valve and is journaled in an antifrlction bearing 35 formed inthehead26. Themainshaftservesasafeedback connection from a servo-motor to the servovalve.

The housing 3|, as shown in Figure 6, has four ports 36, 31, 38 and. 39 which are in constant communication with corresponding annular grooves axially spaced along 'the periphery of the sleeve 29. Each groove has a pair of diametrically opposite radial portsformed therein for establishing communication with the interior of the sleeve. There are four pairs of these ports, each pair being angularly advanced 45 with respect to the preceding pair. The inner member 34 is provided with four longitudinal grooves 49, 4|, 42 and 43 separated by lands 44, 45, 46, and 41. a

The ports 36 and 38 areconneoted bychannels 48 and 49 to opposite ends of a servo-motor cylinder 58 having a contained piston which is connected by a piston rod 52 extending through one end of the cylinder to a crank arm 63. The crank arm is keyed to the main shaft 33. The port 31 is connected by channel 54 to the output of aconstant delivery pump 55.

The port 39 is connected by channel 56 to port 51 of a low pressure relief valve 58. The channel 56 has a branch .connection with the port 59 of this valve whereby the pressure in the channel will shift the plunger 68 against the resistance ofspring 6| tointerconnect port 51 with port 62 which is connected to reservoir throughchannel 63.

It will now be apparent that if the port 31 of the servo-valve is a pressure port and the port 39 is an exhaust port that the opposing lands 44 and 46 will close the exhaust port, while the opposing lands and 41 will close the pressure port whereby the parts will be at rest. Upon rotation of the sleeve 29 in a clockwise direction,

the radial bores'31' will move. out of alignment with the lands '45 and 41, and pressure fluid will.

flow into the grooves 4| and 43. From here the fluid will'flow through port 38, and channel 49 clockwise rotation of shaft 33 through the described interconnections. Fluid from the other end of cylinder 56 will flow through channel 48,,

and port 36,- to the opposing spaces 48 and 42..

Since the opposing radial bores 39' have been moved clockwise out of registry with the lands 44 and 46, the fluid in the spaces 40 and 42 will retm'n to reservoir through channel 56.

It will now be apparent that a clockwise movement of the sleeve will cause actuation of the servo-motor, but the servo-motor will rotate the shaft 33 in a clockwise direction and thereby cause rotation. of the center portion 34 of the servo-valve in a direction to follow up the movement of the sleeve and thereby re-establish the stop position of the parts and' thus stop the motor. Therefore, in order to have the move-,

ment of the motor continuous, it is necessary to maintain a continuous movement or rotation of the sleeve 29. This servo-motor mechanism acts as a power relay between the manual control 23 and the shaft 33.

Rotation of the saft 33 in a clockwise direction will cause rotation of a crank 64 through yieldable friction means comprising discs 66 and 66 keyed to the shaft 33 on opposite sides of the crank, and held into frictional engagement with the crank by means of spring 61 which surrounds the shaft. Adjustment of the spring is made by a nut 68 threaded on the shaft. The object of this friction connection is that upon initial rotation of the shaft; the crank 64 will be moved through a predetermined angular distance to ef- 'fect shifting of plungers 69 and 16 which are connected by an equalizing yoke 1| to a rod 12 pivotally connected to the end of, the crank. The ends of the yoke 1| have a lost motion connection with the plungers 69 and .10. These plungers are normally held in an upward position by springs 13 which are interposed between the lower end of the plungers and the bottom of the valve housing 14 which contains them.

The plunger is a reversing valve plunger for controlling the admission of fluid pressure to the hydraulic jack cylinder l8. As previously mentioned, this cylinder has a pair of channels 2| and 22 and these channels are connected to ports and 16 of valve housing 14. There is also'a shoulder 82 on the plunger 18 is taken up, after which the plunger is depressed to connect the pressure port 11 to port 15 whereby fluid will enter cylinder. l8 through channel 2| and cause rapid traverse movement of the grinding wheel support in a counterclockwise direction. At the same time, fluid will flow through a branch 2| to an operating cylinder -|96 for a limit switch, closing the same to cause rotation of a headstock motor 196'.

The valve plunger 69 is a reversing valve plunger for. automatically controlling a work chuck when the same is utilized for holding work and is operated in the same manner and simultaneous with the reversing valve plunger 10. The plunger 69 controls the flow of fluid pressure to and from a chuck operating cylinder 83 through channels 84 and 85. The cylinder has a contained piston 84' which is connected by a piston rod 85 for operating the chuck.

Thus, rotation of the hand lever 23 will cause actuation of the servo-motor piston 5|, which in turn will rotate the shaft 33. This rotation will continue as long as the handle 23 is actuated and until the piston 5| reaches the end of its cylinder. Rotation of the shaft 33 will cause shifting of the reversing valve plungers 69 and 10 causing automatic closing of the work chuck and rapid traverse movement of the grinding wheel into a grinding position, after which the grinding wheel will continue to be fed in,b y means of a cam 86 which is keyed to the shaft 33 and in co-planar relation with the plunger 20.

After the grinding wheel has completed its inward movement and ground the work to size, the lever 23 is reversed, causing the piston to return and effect counterclockwise rotation of the shaft 33. Attention is invited to the fact that the friction clutch, which drives the crank 64, will slip after the plungers 69 and have reached the limit of their downward stroke, but upon reversal of shaft 33, the plungers will immediately follow up, causing immediate release of the work chuck and rapid traverse retraction of the grinding wheel. After the plungers have reached the limit of their stroke, the crank will move a further distance dependent upon the amount of lost motion.

Attention is invited to the fact that the unit pressure of the fluid supplied to the chuck operating cylinder 83 does not have to be as great as that supplied to other parts of the system, and therefore a reducing valve 81 is provided, having a pressure port 88 which is connected to the pump 55, and a delivery port 89 which is connected by channel 90 to port 9| of the chuck control valve '69. The reducing valve has a spring pressed plunger 82 in which is formed an annular groove 93 of such width that it partially closes each of theports 88 and 89 thereby causing a reduction in pressure in two steps. A branch connection from channel 90 through a choke coil 94 is made. to the upper end of the valve housing for actuation of a piston 95 in oppositiomto the spring 96. Thus, if the pressure rises in the channel 90 beyond a predetermined amount, the plunger 92 will be caused to move downward further restricting the pressure port 88 and causing a greater drop in pressure.

The main pressure in the system may be controlled by a valve 91 having a port 98 which is connected to the pump delivery line 54 and an exhaust port 99 which is connected to the exhaust line 56. The valve plunger I00 is continuously urged by a spring IOI into a position to close the exhaust port 99 but should the occasion arise that the pressure in channel 54 should go above a predetermined amount, said pressure will be communicated through a resistance coil I02 to a plunger I03 reciprocably mounted in the upper end of the valve housing 91 to urge the plunger I00 downward against the resistance of spring IM and thereby open the exhaust port 99 whereby a certain amount of fluid will by-pass to reservoir and thus lower the pressure in the delivery channel 54.

As has heen mentioned supra, the infeeding cycle may be effected by rotation of the hand lever 23, but since this necessitates the continuous attention of the operator at all times, and since uniform timing can not be obtained if dependence is placed upon manual operation, a power operated driving and timing mechanism has been provided for actuation of the manual control lever, thus insuring uniformity for each cycle of operation. This cycle control mechanism includes a fluid operable motor comprising a cylinder I04 having contained piston I05 which is operatively connected by a piston rod I06 to a crank arm I01. The crank arm is keyed to shaft I08 which has a second crank arm I09 connected by a link IIO to a crank III integral with the manually. operable lever 23. The cylinder I04 has a pair of ports H2 and I I3 located in opposite ends thereof and connectedv by chanels H4 and 5 respectively to ports H6 and H1 of a regenerative valve II 8.

Pressure fluid for operation of the motor I04 is supplied by the pump 55 through a channel II9 which is'a branch of the main delivery channel 54. The channel 9 is connected to port I of a pilot valve HI and to port I 22 of the' reversing valve I23. The reversing valve I23 has a fluid shiftable plunger I24, the position of which is controlled by the pilot valve I2I. When the plunger I24 is shifted to the right, the port I22 is con-- nected by the cannelure I25 toport I26 whereby the fluid pressure will flow through channel I21 to ports I28 and I29 of the regenerator valve I I8. When the regenerative valve plunger I30 is in the position shown, the port I28 is connected to the motor port II1 whereby fluid pressure will flow to the right hand end of cylinder I04 causing actuation of piston I05. The fluid from the other end of the cylinder will return through channel II 4 to port II6 of the regenerative valve which at this time is connected by cannelure I3I to port I32 whereby the fluid will continue through channel I33 to port I34 'of the reversing valve.

With plunger I24 in a right" hand position, the

port I34 will be interconnected with port I35 whereby the returning fluid will continue through channel I36 to port I 31 of the rate control valve I 38, and to port I39 of the run ahead valve I40.

.The rate control valve has an adjustable plunger I4I which is held against the end of an adjusting shaft I42 by a spring I43. Shaft I42 is threaded at I44 in the housing I 38 and rotated by the knurled knob I45. The plunger I has a spool I46 in which is formed a V-notch I41 movable relative to the'port I31 for regulating the flow therethrough. This constitutes a form of hydraulic resistance which varies the back pressure in channel I36 and thereby in the cylinder I 04. After the fluid passes the hydraulic resistance formed by the notch I41, it collects in an annular groove I48 formed in the plunger which is in constant communication with a port I 49. This port is connected to an exhaust channel I50 through which the fluid is returned to the exhaust line 56 of Figure 7 and thereby to the common reservoir ISI for the pump 55.

An automatic cycle of operation is initiated by rotating the hand lever 23- through an arc of substantially 20. This will cause rotation of the shaft I08 through the same angle and thereby rotation of a cam I52 fixed to the shaft I08. The plunger I53 of the pilot valve I2I is held in engagement with the periphery of this cam by a spring I54. When the parts are in the starting position shown in Figure 8, the pressure port I20 is connected by cannelure I55 to port I56 and thereby through channel I 51 to the right hand port I58 of the reversing valve I 23, shifting the plunger I 24 to the left. As the plunger I 53 of the pilot valve moves toward the right under the action of cam I52 during clockwise rotation will flow through channel I6I to the left handport I62 of the reversing valve I23 shifting the plunger I 24 thereof to the right. This will establish the previously described pressure connections to the cylinder I04 and from there on the cycle will continue automatically.

The shaft I08 has a second cam I63 attached thereto against the periphery of which the plunger I30 of the regenerative valve is held by a spring I 64. The cam I63 has a profile surface I65 which is of constantradius throughout most of the rotation of shaft I08 but near the end of the stroke there is a sudden rise which shifts the plunger I 30 toward the right a suflicient distance to uncover the pressure port I29. The

space I66 and act on the differential areas I61 and I68 of the plunger. The resultant differentla'l pressures will fire plunger I30 toward the right against the compression of spring I64. The firing of this valve will take place at. the time that the servo-motor piston in Figure '1 has reached theend of its stroke and rotated the cam 86 the maximum amount and thus completed the movement of the grinding wheel tonel I1Iwhich is connected to the extreme end of the space I69 and leads to port I12 of a tarry control valve I13. This valve has a plunger I14 which is held by a spring I15 against the end of an adjusting shaft I16 which is threaded at I11 in the valve housing. A knurled knob I18 secured to the end of the shaft I16 serves as means for effecting adjustment of the valve.

The plunger I14 has a spool I19 which is movable relative to the port I12 .and in the spool "is formed a V-shaped notch I80 which acts as an hydraulic resistance to vary the back pressure in the channel HI and thereby in the space I69.- This hydraulic resistance will determine the rate of escape of fluid into an annular groove I8I formed in the plunger which is connected by an open port I82 to the return line I50 and thereby the length of tarry between the termination of the forward movement and the beginning of the return movement.

When the regenerative valve plunger I30 has completed its shifting movement, the pressure port I 26 will be connected to the motor port H6, and the motor port II1 will be connected to the exhaust port I10. This will cause return movement of the piston I05. Since the supply fluid will be coming directly from the pump 55 and the return fluid will be returning directly to reservoir through the low pressure relief valve 58, the return movement will be at a rapid traverse rate.

Although the cam I63 will be rotating in a direction to reduce its effective radius during this return movement, the plunger I30 of the regenerative valve will still be held in a right hand position due to diflferential pressure in space I66 and cannot be returned until this pressure is .broken.

As the shaft I08 returns vcounterclockwise, the rise on cam I52 is decreasing, permitting the plunger I53 to move'toward the left under presport I60 of the pilot valve. In other words, they exhaust of fluid from the left end of the reversing valve will be delayed whereby the shaft I08 will continue to rotate and thus have time to return the control lever 28 605 168 starting position, before the reversing valve shifts a sufllcient distance to release the holding pressure, on the regenerative valve.

When the pressure in chamber I66 is dissipated, the spring I64 returns the plunger I30 to its left hand position whereby'the motor port II6 will bereconnected to port I32 and motor port II1 will be connected to the port I26. Since port I28 is disconnected from pressure at this time, the cycle of operation will stop.

It will be understood that the return move-- ment of piston I05 will rotate the cranks I01 and I09 in a counterclockwise direction and thereby through the servo-motor control valve cause return movement of piston 5|. When the regenerative valve returns to its normal position, fluid pressure will be cut off from. cylinder I04 whereby a manual movement of the manual control lever 23 will be necessary to initiate another cycle of operation. r

The run ahead valve I40'is provided for the purpose of permitting the operator at will to move the grinding wheel toward the work piece at a faster rate than that determined by the rate valve I38. This is accomplished by providing a plunger I84 which is normally held in a position to disconnect the left hand end of cylinder I85 in which the plunger ,is slidable from ports I86 as mentioned supra. The channel I36 through which the fluid flows from the left hand end of cylinder I04 to reservoir is connected in parallel to ports I31 and I39. The'port I39 is in com;

munication with the space I8j5'so that whatever pressure-exists in channel I36 is constantly acting on the end of plunger I 84 tending to shift the same toward the right. This movement is opposed by a spring I81 which is interposed between the end of the valve housing and a cup-shaped piston I88 which engages the end of plunger I84. The spring is assisted by fluid pressure from the pressure supply line II9 which is connected through a hydraulic resistance I69 to the space I90 which contains the spring. The piston I88 has a small coaxial hole formed therein whereby the fluid pressure in the space I90 may flow into the space I9I on the other side of the piston. This would tend to equalize the pressure on opposite sides of the piston but due to the dash pot efiect it should damp out sudden movements of the piston I86. Should the operator exert continuous pressure on thehandle 23 after the auto-' matic cycle has started, he would increase the back pressure in the left hand end of cylinder I04 and thereby increase the pressure in the space I85 which would cause movement of the plunger I84 toward the right a sufficient distance to influid to reservoir 'must pass through the rate control valve.

The automatic cycleactuating mechanism shown in e 10 maybe rendered inoperative by a cut-oii valve I92, which. has a rotatable plunger I93 whereby upon rotation of the plunger through 90 fromthe position shown, the

channels II4 and H5 will be interconnected by could be disconnected to break the connection of the motor I04 with the servo-valve.

There has thus been provided an improved form of infeed mechanism which may be built as 'a separate unit for attachment to any suitable form of machine tool which has a manually operable infeeding cycle and which it may be-desired to operate automatically.

What is claimed is:

1. In a machine tool having a work support and a tool support and a power operable mechanism for effecting an infeed cycle between the supports including a manual control, the combination of a one-cycle driving and timing mechanism for said control, including a rotatable shaft, motion transmitting connections from said shaft to said control, a power operable motor for rotating said shaft, a source of fluid pressure for said motor, and means responsive to a prescribed angular movement of the manual control from a prescribed starting position to connect said source of pressure to said motor to initiate an automatic cycle of movement of said manual control.

2. In a machine tool having a work support and a tool support and a power operable mechanism for effecting an infeed cycle between the supports including a manual control, the combination of a one-cycle driving and timing mechanism for said control, including a rotatable shaft,

motion transmitting connections from said shaft to said control, a power operable motor for rotating said shaft, a source of fluid pressure for said motor, means responsive to a prescribed angular movement of the manual control from a starting position to connect said source of pressure to said motor to initiate an automatic cycle of movement of said manual control, and means to control the rate of flow of fluid pressure to said motor and thus determine the timing of said cycle.

3. In a machine tool having a work support and a tool support and power operable mechanism for effecting an infeeding cycle between the supports, including a manual control, the combination of a one-cycle driving and timing mechanism for said control, including a rotatable shaft, a power operable motor for rotating said shaft, a source of fluid pressure for said motor, motion transmitting connections from said manual con- I trol to said shaft whereby said shaft will 'be initially actuated by said control, means respon sive to the initial rotation of said shaft-to connect said source of fluid pressure to said motor whereby subsequent rotation of said shaft will be effected by said motor to effect an automatic cycle, and additional means responsive to rotation of said shaft for disconnecting said source of fluid pressure from said motor automatically.

' 4. In a machine tool having a work support and a tool support and a servo-motor mechanism operatively connected to one of said supports for moving the same toward and from the other support including a servo-valve, and a manual control, whereby any movement of the manual control will result in movement of the slide; the combination of a one-cycle driving mechanism for said manual control which will automatically effect advance and retractive movements thereof in predetermined timed relation, including a fluid manual control, a source of pressure, valve means for connecting said source of pressure to said motor, and additional valve means for disconnecting said source of fluid pressure from said motor, both of said valve means being operable in timed relationto the rate of "actuation of said motor.

5. -In a machine tool having a work supportand a tool support and cam means operatively connected. for effecting approach and retractive movements between said supports upon opposite actuation of said cam, the combination of a fluid operable motor mechanically connected for actuation of said cam, a servo control valve for governing the admission of fluid pressure to said cylinder, said servo-valve having a manual control, a second fluid operable motor for oscillating said manual control, automatic timing mechanism for said motor whereby it will elfect movement of said manual control at a predetermined rate during one direction of movement, means automatically operable for reversing the direction of movement of said last named motor, means for delaying the starting of said reversing movement, and means for causing said return movement to be effected at a rapid traverse rate.

6. The combination with an infeeding mechanism for a machine tool, said mechanism having the length of said tarry and subsequent reverse connection of pressure to said motor, said power return movement of the motor being ,of greater length than the power advancing movement.

7. In a machine tool having a servo-motor mechanism for effecting relative movement between a grinding wheel and a work piece,the combination with a servo-valve control therefor, of a, fluid operable motor for reverse actuation of said servo-valve, a source of fluid pressure for said motor, cam operated valve means for connecting said source of pressure to said motor to effect one direction of actuation thereof, a pressure differential operated valve for reversing said motor, means operable by said motor for creating said pressure differential to effect shifting of said valve, and adjustable means for determining the rate of said shifting of said valve and therebythe length of tarry between the advance and return of said motor.

8. In a grinding machine having a work support and a grinding wheel support, and a servomotor mechanism for effecting a relative infeeding movement between said supports, said servomotor mechanism including a servo control valve having a manually operable-control, the combination of a power driving and timing mechanism for oscillating said control, including a fluid operable motor, motion transmitting connections from said motor to said controLa source of fluid pressure, cam operable valve means effective upon rotation of said control to connect the source of fluid pressure to said motor to effect automatic actuation thereof, adjustable means for controlling the rate of said actuation, a regenerative control valve for reversing the connections to said motor, cam operated means for determining the time of firing of said valve, and motion transmitting connections coupling said motor to each of said cam means.

9. In a grinding machine havinga grinding wheel support and a work support, one of which is movable relative to the other to effect an infeeding grinding cycle, the combination with power operable means for effecting said movement, including a control valve having a manually operable handle, the combination of a shaft, 9. fluid operable motor for rotating said shaft, motion transmitting connections from said shaft to said control, means to rotate said shaft upon actuation of said control handle, cam operated .valve means for connecting the source of fluid pressure to'said motor, a cam therefor carried by said shaft whereby after a predetermined .manual movement the shaft will be power rosure on said motor and causing return rotation of trol valve fluid shiftable to one'position to connect,

said source of pressure to said motor, and to a second position for disconnecting said source of pressure from said motor, a pilot valve therefor, means actuable upon initial movement of said manual control to shift said pilot valve and thereby fluid position said control valve in a' running position, and means operable by said motor to fluid position said control valve in its'other position. I

lLIn a machine tool having a work support and a tool support, and a servo-motor mechanism operatively connected to one of said supports for moving the same toward and from the other support, including a servo-valve, and a manual con trol therefor, whereby any movement of the manual control will result in servo-motor actuation of the movable support; the combination of a one-cycle driving mechanism for said manual control including a fluid operable motor mechanically connected to said manual control, a source of fluid pressure for said motor, a control valve fluid shiftable to one position to connect said source of pressure to said motor, and to a second position for disconnecting said source of pressure from said motor, a pilot valve therefor, means actuable upon initial movement of said manual control to-shift said pilot valve and there-' by fluid position said control valve in a running position, said pilot valve being subsequently opervalve in its 0th r 12. In a machine tool having a work support and a tool support, the combination with a first fluid operable motor-mechanicallyconnected for t fluid position said control effecting relative movement between said supports, of a control valve including relatively movable parts for governing the rate and direction having a manual control, a feed-back connection from the motor to the other part of said valve, a second fluid operable motor mechanically connected to said manual control for eflecting auto-,

matic cyclic movement thereof, a rate and direction control and timing circuit for said last named motor, and a valve for disconnecting said second motor from said circuit whereby said manual control may be utilized for set-up purposes without interference from the last named motor.

13. In a machine tool having a w'orksupport and a tool support, the combination of mechanism for effecting relative movement between the supports, including a pair of parallel shafts, an infeeding cam for the movable support carried by one of said shafts, hydraulic motors of the piston and cylinder type operatively connected to each of said shafts, a control valve for one motor including relatively movable parts, one of which is connected to one shaft and the other of which is connected to the other shaft, 9. manual control leverfor one of said parts, a source of pressure connected to said control valve whereby servo operation of the connected motor may be effected by the manual control, and valvemeansfor con necting said source of pressure to the other of said motors, said last named valve means being operable by a cam attached to the other of said shafts, whereby a predetermined angular movement of said manual control will cause subsequent automatic operation of said servo operation.

14. In a machine tool having a work support and a tool support, and a servo-motor mechanism operatively connected for effecting relative movement of one of said parts toward and from the other, including a servo-valve having a man ual control, the combination of a fluid operated means for driving said manual control through a predetermined cycle of operation, including a fluid operable motor, linkage connecting said motor to said manual control, a source of pressure, a starting valve for connecting said source of pressure to said motor, a pilot valve for eifecting fluid shifting of said starting valve, a pressure differential shiftable reversing valve, a supply channel from said'starting valve terminating in a pair 'of ports in said lastvnamed valve, means in the reversing valve forconnectlng one of said ports to said motor, and additional meansin the valve responsive to mechanical shifting thereof to connect the other port for pressure differential

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