US2183490A

US2183490A - Hydraulically operated cylindrical grinding machine

Info

Publication number: US2183490A
Application number: US284658A
Authority: US
Inventors: Carl G Flygare
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1939-07-15
Filing date: 1939-07-15
Publication date: 1939-12-12
Anticipated expiration: 1956-12-12

Description

Dec. 12, 1939. I c, Q FLYGARE 2,183,490

HYDRAULICALLY OPERATED CYLINDRICAL GRINDING MACHINE Filed July l5, 1939 2 Sheets-Sheetl 1 az si:

IIHIIII Il Cam. EJrLYEFfm- @Mmmm lDevx. l2, 1939. ne. FLYGARE HYDRAULICALLYl QPERATD CYLlNDRICAL GRINDING MACHINE Filed July 15. 1959 2 sheetssheet 2 Patented Dee. 12, 1939 HYDBALICALLY ori-:RATED GYLINDBICAL GRINDING MACHINE Carl G. Flygare, Worcester, Mass., assigner to Norton Company, Worcester, Mass., a corporay tion of Massachusetts Appucauoouiy 15, 193s, serial No. zsassvs s claims.

The invention relates to grinding machines, and more particularly to an electrically controlled .hydraulically .operated cylindrical type grinding-machine.

One object of the invention is to provide an improved electrically controlled, hydraulically operated grinding machine with an improvedcycle control mechanism. A further object of the invention is to provide an interlocked control for a grinding machine Wheel feed mechanism, a footstock, and a work ejecting mechanism. A further object of the invention is to provide a hydraulically operated grinding machine with an improved electrical control mechanjsm,

A further object of the invention is to-provide a cyclic wheel feeding mechanism which is electrically interlocked with the footstock so that the wheel cannot be advanced until the footstock center is in an operative position. Another .ob-

ject ofthe invention is to provide an electrical interlock between the Work ejector mechanism and the other mechanisms lof the ymachine whereby Ithe wheel feed and the footstock controls are rendered inoperative during the work unloading and loading operations. Other objects will be in part obvious or in part pointed out hereinafter.

t The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and

the scope of the application of which will be indicated in the following claims.

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

Fig.- 1 is a front elevation of the improved grinding machine;

Fig. 2 is a longitudinal sectional view through the headstock and footstock and through the hydraulic wheel feed mechanism combined with an electrical and hydraulic diagram to illustrate the operative cycle of the machine;

Fig. 3 is a longitudinal sectional view, on `an enlarged scale, through the footstock, showing thegelectrical interlock and control mechanism; and

4 is a fragmentary longitudinal sectional view, on an enlarged scale, through the headstock, showing the work ejector-mechanism.

. A grinding machine has been illustrated in the drawings which is of the same/ general type as `that shown in the prior U. S. patent to Wood No. 2,071,677 dated February 23, 1937. A grinding machine has4 been illustrated in the draw- -ings comprising a base III which supports a longitudinally reciprocable work supporting table II on the usual V-way and' at way (not shown).. The work table II may be traversed longitudi- 5 nally either manually or by power by any of the well knownmanual or power operated. mechanisms. As illustrated in the drawings, a manually operable traverse mechanism has been il1 istrated comprising a rack vbar I2 depending 10 from the'table II which meshes with a gear I3. The gear I3 is rotatably supported within the base I0 of the machine. A gear I4 is mounted and arranged to rotate with the gear I3 and meshes with a gear I5 mounted on the inner end l5 of a rotatable shaft I6. A manually operable hand traverse wheel I1 is mounted on the outer end of the shaft I6. By rotating the hand wheel I1 in either direction, the work supporting table I I maybe traversed longitudinally in the desired 20 direction.

.Power traverse The table II may, if desired, I'be reciprocated longitudinally by a power operated mechanism, such as that shown in the prior U. S. Patent No. 25 2,071,677 above referred to, to which reference may be had for details of disclosure not contained herein. The power operated table traverse mechanism is preferably a fluid pressure mechanism comprising a cylinder 20 which is fixe'dly mounted to the underside of the table I I. The cylinder 20 contains a pair of spaced pistons (not shown) which are connected by a pair of hollow connecting rods 2| and 22 to a pair of

hollow brackets

23 and 24, respectively, which 35 are fixedly mounted on opposite ends of the base I0.

The base III is formed as a hollow box-like construction, the lower portion of which'serves as a iiuid reservoir 25 for the iiuid pressure system. Fluid is drawn from the reservoir 25 through a pipe 26 by means of.a motor driven iiuid pump 21 and is forced through a pipe 28 to a table control valve 29. A fluid pressure reu lief valve 30 is connected in the pipe line 28 which is arranged to allow fluid under pressure ,to by-pass through a pipe 3| into the reservoir valve29 'is also connected by means of a pipe 55 86 with the bracket 24 which forms a huid connection with a cylinder chamber at the righthand end of the cylinder 20. By actuating ythe control valve 29, the table il may be caused' to traverse in either direction, as desired. The control valve has not been illustrated in detail in the present case since it is not considered to be a part of the present invention. For further details of the tablecontrol valve 28, reference may be had to the above-mentioned prior Patent No. 2,071,677.

A table actuated reversing lever 88 is pivotally mounted on the front of the machine base and is operatively connected to actuate the table control valve. A pair of

adjustable table dogs

88 and 40 are adjustably supported by a V-slot formed in the front edge of the table il and serve automatically to actuate the lever 88to shift the control valve 29.

The speed of reciprocation of the table Il is controlled by means of a speed control valve (not shown) which is actuated by movement of the control lever 38 toward and from the front of the machine. This valve and its connections with the lever 38 are clearly disclosed in the above-mentioned prior patent.

As illustrated in the drawings, the base I0 also supports a rotatable grinding wheel 45 which is. supported on one end of a rotatable wheel spindle (not shown) which is journalled in bearings carried by a transversely movable wheel slide 46. The grinding wheel 45 may be driven in any suitable manner such as, for example, by means of an electric motor 41 mounted on the upper surface of the wheel slide 46. The motor is provided with a shaft 48 which supports a pulley 49 which is in turn connected by means of a belt 50 with a pulley 5I mounted on the righthand endof the wheel spindle (Fig. l).

The work supporting table il serves as a support for a rotatable work supporting mechanism comprising a headstock 50 which is provided with a rotatable headstock spindle 5|. The spindle 5| is provided at its right-hand end with a work supporting center or chuck 52, which in the present case has been illustrated as a female center, to engage and support a frusto-conical end portion of a work piece 53. The spindle 5I is rotated by means of an electric motor 54 mounted on the upper surface of the headstock 50. 'Ihe motor 54 is provided with a driving pulley 55 which is of the multiple V-groove type. The pulley 55 is connected by a multiple V-belt 56 with a multi-grooved pulley 51 mounted on the lefthand end of the headstock spindle 5I (Fig. 2).

The other end of the work piece 53 is supported by means of a footstock 60. The footstock 68 is provided with a longitudinally movable spindle 6| which is provided at its outer end with a footstock center 62 which is arranged to rotatably support the right-hand end of the work piece 53. The footstock spindle 6I is preferably moved to and from an operative position by means of a fluid pressure mechanism comprising a cylinder 83 having a piston 64 slidably mounted therein. A spring 65 is interposed between the piston and the footstock spindle .6| and is arranged to yieldably maintain the footstock center 62 in operative engagement with the work piece 58 during the grinding operation. -Fluid may be admitted through the pipe 66 into a cylinder chamber 61 to cause the piston 64 and the spindle 6| together with the footstock center 62 to move toward the left (Fig. 2) into an operative position or, if desired, fluid under pressure may be admitted through a pipe 88 into a cylinder chamber 88 to cause the piston 64 and footstock center 82 to move to an inoperative position. The fluid pressure system and the control mechanism therefor will be"descrlbed hereinafter.

An interlock ls provided to prevent the grinding wheel from starting its forward feeding movement until the work center 62 is in an operative position. A normally open limit switch 15 is interconnected with the wheel feeding mechanism in a manner to be hereinafter described. A lever 16 is pivotally mounted on a stud 11 which is fixedly supported on the footstock 68. The lower end of the lever 18 is arranged in the path of a slidably mounted rod 18 which is slidably supported by a stationary part of the footstock 88. When the footstock piston 64 moves toward the left (Fig. 3) to move the footstock center 62 into supporting engagement with the end of the work piece 53, the piston 84 engages the end of the rod 18 and moves it endwise toward the left. This movement of the rod 18 serves to rock the lever 16 in a clockwise direction against the compression of a spring 18. During the clockwise movement of the lever 16, it engages the actuating roller of the limit switch 15, which serves to close the limit switch 15 only when the piston 64 and the footstock center 62 are moved into an operative position.

Work ejector The headstock 50 is provided with a work ejector mechanism which is arranged automatically to eject the work piece 58 from the female cen? ter 52. As illustrated in the drawings, the ejecis iixedly supported on the end of the piston' rod 84. A spring 81 surrounds the piston rod 84 and is interposed between the piston 85 and the left-hand end of the cylinder 86 which serves normally to hold the piston and the ejector rod 88 in an inoperative position, as illustrated in Fig. 2. The ejector rod is moved to eject the work piece 53, by means of a iluid pressure mechanism. Fluid under pressure is admitted through a pipe 88 into a cylinder chamber 89 to 'move the piston 85 and piston rod 84 toward the left (Fig. 2), which movement serves to rock the lever 82 in a clockwise direction.' AThe clockwise movement of the lever 82 serves to move the ejector rod toward the right (Fig. 2) to eject the work piece 53 from the female center 52.

A work supporting or loading cradle 88 is mounted on the table il and serves to support the work piece 53 during the loading and electing operations.

Wheel feeding mechanism A wheel feeding mechanism is provided to control the feeding movement and adjustment of the grinding wheel 45 toward and from the work support. The wheel slide 48 is provided with a depending half nut 85 which meshes with a rotatable cross feed screw 86. The feed screw 86 is rotatably supported in bearings 81 and, in the base i8. The feed screw 88 may be rotated manually for adjusting the position of.

the wheel slide 46 in setting up the machine,

by a manually operable feed lmechanism to be hereinafter described. L

In order that the wheel slide 46 may be rapidly moved toward the work piece 53 to grind the same, the feed screw 96 is connected to a piston rod 99. A fluid pressure cylinder is arranged in axial alignment with the feed screw 96 and contains a slidably mounted piston |0| which is connected with the piston rod 99. The uid pressure pump 2l forces -fluid through the pipe 28 to a feed control valve 02. The feed control valve |02 is preferably of the piston type, comprising a valve stem |03 having a plurality of valve pistons formed `integrally therewith. This fluid pressure feeding mechanism,'as illustrated in Fig. 2, is substantially identical to that shown inthe prior U. S. patent to Cole and Amidon No. 2,101,790 dated December '1, 1937, to which reference may be had for details of disclosure not contained herein. In the position of the feed control valve |02 (Fig. 2), fluid under pressure passing through the pipe 28 enters a valve chamber |04 and passes through a passage into a cylinder chamber .|05 formed at the lefthand end of the cylinder |00 (Fig. 2) to cause the piston |0I, the wheel slide 46, and the grinding wheel 45 to move into a rearward or inoperative position.A During this rearward feeding movement of the grinding wheel, fluid is exhausted from a cylinder chamber |06 formed at the right-hand end of the cylinder |00 (Fig. 2), through a passage, and through a valve chamber |01, and out through a-pipe |08 which exhausts into the reservoir 25.

The forward end of the valve stem |03 is pivotally connected to the .upper end of a lever |09 which is pivotally supported on a fixed stud ||0. A spring is connected between the lower end of the lever |09 and a fixed stud ||2 and serves normally to hold the feed control valve |02 in the position illustrated in Fig. 2 to move and hold the grinding wheel 45 and its supporting slide 46 in its rearward or inoperative position. A solenoid ||3 yis connected to the lower end of the lever |09 and is arranged so that when energized, it rocks the lever |09 in a counterclockwise direction, moving the valve stem |03 toward the left (Fig. 2) to shift the control valve |02 also toward the left so as to admit uid under pressure passing through the pipe 28 and valve chamber |04 into the cylinder chamber |06 to cause a forward feeding movement of the grinding wheel 45. The admission of fluid under pressure to'the cylinder chamber |06 produces a rapid forward movement of the grinding wheel 45.

Dash pot of the work piece 53 being ground. As illustrated in Fig. 2, an outwardly extending casing |5 is fixedly mounted .to the end of the cylinder |00 and contains a pair of diametrically arranged spaced dash pot pistons ||6 and which slide within dash pot cylinders formed within the casing |I5. The dash pot pistons ||6 and normally are held in a rearward position by means of springs. During the rapid approach of the grinding wheel 45, the dash pot pistons are inoperative. The piston rod 99 extends toward the rear of the machine and is provided at preaching movement continues until an adjustable collar |23, carried by a threaded end portion |24 of the piston rod 99, engages the end of the sleeve |20. 'I'he continued movement of the piston |0| is resisted by the dash pot pistons H6 and Il'l, which force fluid under pressure from the dash pot cylinders through an adjustable needle valve |25 into a reservoir |26. By adjustment of the needle valve |25, the exhaust of uid from the dash pot cylinders may be readily controlled to produce the desired grinding infeed, so that the grinding wheel will be moved into the Work piece to grind the same at the desired rate of speed. This dash pot mechanism is substantially the same as that shown in the prior U. S. patent to Cole andAmidon No.

. 2,101,970 dated December 7, 1937, and since this feature is not considered to be a part of the present invention, the details of disclosure have not been completely described herein. For details of -disclosure not contained herein, reference may be had to the prior patent above mentioned.

The fluid reservoir '|26 and the dash p'ot cylinders form a separate fluid system which is independent of the main feed cylinder |00. In order to ll the reservoir |26, a pipe |21 is connected with the fluid pressure pipe 28 which leads from the fluid -pump 21, and a manually opera/ble valve |28 in the pipe line |21 serves to admit fluid from the pump into the reservoir |26 to ll the dash y pot system in settingv up the machine `and to maintain it full during use. An overflow pipe |29 is provided which is connected'with the exhaust pipe |08 to convey excess fluid from the reservoir |26 to the main reservoir 25. If desired, the valve |28 may -be maintained lightly open 'during the use ofthe machine, o that the reservoir |26 will be at all times filled and any overflow therefrom may readily return to the main reservoir 25. In order to allow the dash p'ot cylinder chambers to fill rapidly as the wheel slide 46 moves rearwardly, a ball check Valve |30 is. provided in the dash pot cylinder casing I5 which is connected by means of a pipe I 3| with the reservoir |26. By providing the ball check valve |30, fluid is quickly admitted into the dash -pot cylinders instead of being drawn wholly through the needle valve |25.

Positive stop In order to grind the work piece 53 to a predetermined size, it is necessary to feed the grinding wheel 45 toward the work piece 53 to grind the same and then to stop the infeed and allow the grinding wheel 45 to grind out or to allow the sparks to die out `in order to round up or finish grind the work so that it will be ground to a true cylindrical surface of a predetermined size. As illustrated in the drawings, a positive stop sleeve |32 surrounds and is adjustably supported on the sleeve |20 and is arranged to engagea dash pot cylinder head when the grinding wheel has advanced to a predetermined position positively to stop the forward advance of the Y/wheel for a flnish grinding operation.

Manual feed adjustment shaft |44 is journalled in suitable bearingsk (not shown) in the base |0. The shaft |44 carries at its forward end a gear |45 which meshes with a small gear (not shown) which is supported to rotate with a manually operable feed wheel |46. The feed screw 96 may be rotated manually by rotation of the manually operable feed wheel |46 in either direction to adjust the position of the wheel slide 46 and the grinding wheel 45. A reciprocable feed pawl |41 is provided for intermittently actuating the feed wheel |46 at the ends of the table stroke when the machine is set up for a traverse grinding operation. 'I'he feed wheel |46 is provided with a manually operable micrometer adjusting mechanism' |48.to facilitate adjustment of a stop abutment which is carried by the feed Wheel |46 and is arranged to engage the feed pawl |41. This mechanism has not been illustrated in detail. since it is not considered to be a part of the prisent invention. Reference may be had to the prior U. S. patent "to Norton No. 762,838 dated June 14, 1904, for

details of disclosure not contained herein.

'I'he fluid pressure pump 21 also supplies uid under pressure for actuating the footstock 60. A solenoid valve is provided for controlling the passage of uid under pressure to operate the footstock. 'I'he valve |60 is preferably a piston type valve having a plurality of valve pistons |6|, |62 and |63 formed integral with the valve stem. A solenoid |64 is connected to the upper end of the valve stem and serves when energized to shift the valve in an upward direction. A spring |65 surrounding the valve stem and interposed be-` tween the valve piston |6| and the end of the valve casing serves normally to hold the valve in. a downward position. Fluid under pressure from the pump passing through the pressure pipe 28. Passes through a pipe |66 into a valve chamber located between the valve pistons |62 and |63 and passes out through the pipe 68 into the cylinder chamber 69 to move the footstock center 62 toward the right into an inoperative position, gs shown in Fig. 2. During this movement of the footstock center 62, fluid is exhausted from the cylinder chamber 61 through the pipe 66 into a valve chamber located between the valve pistons |6| and |62 and exhausts through a pipe |66 into the main reservoir 25. When the solenoid |64 is energized, the valve pistons |6I, |62, and |63 move upwardly so that fluid under pressure passing through the pipe |66 into the valve chamber between the 4valve pistons |62 and |63, passes through the pipe 66 into the cylinder chamber 61 to move the piston 64 and footstock center 62 toward the left into an operative position to support the right-hand end of the work piece 53.

During this movement of the footstock center l2 into an operative position, fluid within the cylinder chamber 68 exhausts through the pipe 68 and passes out through a pipe or passage |88 into the pipe |68 which in turn exhausts into the main reservoir 26.

The ejector mechanism is similarly actuated by fluid under pressure from the pump 21'. The passage of fluid to the ejector mechanism is controlled by a solenoid valve |10 which is preferably a piston type valve comprising valve pistons |1|, |12 and |13. An electric solenoid |14 is connected to the upper end of the valve stem and serves when energized to shift the valve in an Yupwar'd direction. A spring |15 which surrounds the valve stem and is interposed between the valve piston |1| and the end of the valve casing, serves normally to hold the valve in a downward position. Fluid under pressure from the pump 21 passing through the pipe 28 also passes through a pipe |16 into a valve chamber located between the valve pistons |12 and |13. In the position of the valve (Fig. 2), nothing happens. The cylinder chamber 86 is connected by the pipe 88 with a valve chamber located between the valve pistons |1| and |12 which, as illustrated, is connected by a pipe |18 which exhausts fluid into the main reservoir 25.` When the solenoid |14 is energized, the valve pistons |1|, |12 and |13 are moved upwardly against the compression of the spring |15 so that lfluid under pressure passing from the pipe |16 into the valve chamber located between the valve pistons |12 and |13, passes through the pipe 88 into the cylinder chamber 88 to cause the piston-85 and the piston rod 84 to rock the lever 82 in a clockwise direction, which in turn shifts the ejector rod toward the right (Fig. 2) to eject the workpiece 68 from the female center 52.

The improved grinding machine is provided with an interlock which prevents a forward feeding movement of the grinding -wheel until the footstock center 62 is in supporting engagement with the work. Similarly, the footstock center is interlocked so that it cannot be withdrawn from supporting engagement with the work until the wheel slide has moved to its rearward position. In the preferred construction an electrical interlock is provided. The machine receives its source of power from the power lines indicated diagrammatically (Fig. 2). A manually operable push button switch 8| is provided for starting the grinding cycle. The electrical circuit is arranged so that the push button switch must be held closed until the grinding wheel 45 and its supporting slide 46 have started on the forward approaching or feeding movement. The closing of the push button switch |8| energizes a solenoid |82 of a mechanical latch-in electrical reset relay, such as that manufactured by the Struthers Dunn Inc. of Philadelphia, Pa. The energizing of the solenoid |82 closes a switch |83 which is normally held open by means of a spring |84. When the switch moves downwardly into a closed position, a spring-pressed latch |85 engages a projecting lug |86 on the switch plunger and locks the switch |83 in an operating position. The closing of the switch |83 serves to energize the solenoid 64 to shift the footstnck control valve |60 upwardly so as to admit uid under pressure through the pipe 66 into the cylinder chamber 61 to cause the footstock center to move into supporting engagement with the work piece 53.

When the piston 64 reaches the end of its operative stroke, the rod 18 acting upon the pivotally mounted lever 418 closes the normally open limit switch 19 which in turn sets an electrical time delay relay |81 in motion. The time delay relay |81, as illustrated, is one of the well known electrical time delay automatic reset relays, such as thatvknown as the Microex instantaneous reset timer relay manufactured by Eagle Signal Corporation of Moline, Illinois, and which is covered by U. S. Patent No. 1,794,762 to J. A. Garell, to which reference may be had for details of disclosure not contained herein. The relay |81 is connected to energize the feed control solenoid III which in turn shifts the feed control valve |02 to initiate a forward feeding movement of the grinding wheel 45. A compression spring |88 serves to hold the latch |85 in an operating position. 'Ihe latch |85 is arrangedto be automatically withdrawn at the desired time.

A pair of normally open limits switches |90 and |9| are provided adjacent to the rear end of the piston rod 99 and are arranged to be actuated by means of a cam or dog |92 which is adjustably supported on the threaded end portion |24 of the piston rod 99 and serves in a manner to be hereinafter described to aid in the interlocking of a various mechanisms of the machine.

The manually operable starter push button |8| must be held in a closed position until the footstock center 62 is in supporting engagement with the work piece and the wheel starts its forward feeding movement, and must be held closed until the dog or cam |92 rides off the actuating roller of the normally open limit switch |9| so that the switch |9| opens to break the circuit, thus rendering a solenoid |94 which operates the latch |85 inoperative.

The forward feeding movement of the grinding wheel 45 continues for a definite time interval, as controlled by the adjustable time delay relay |81', which serves after the said time interval automatically to break the circuit so as to deenergize the solenoid ||3, thus releasing the compression of the spring ||"which shifts the feed control valve |02 into its rearward position to cause a rearward movement of the Agrinding wheel.

. When the wheel approaches the forward end of its stroke, the cam or dog |92 on the rear end of the piston rod 99 engages the actuating roller of the normally open limit switch |80 which serves to break a circuit, thus deenergizing a solenoid |95 which allows the released compression of a spring |96 to withdraw a latch |91 from engagement with the lug |98. The withdrawal of the latch |91 releases the compression of a spring |99 which moves the switch member 200 of the mechanical latch-in electrical reset relay into a closed position, thus closing the circuit which is connected to the solenoid |94. The solenoid |94, however, is not energized since the normally open limit switch |9| is connected in series therewith. The switch 200 remains in a closed position until the wheel slide moves to its rearward position and the cam or dog |92 again engages the actuating roller of the normally open limit switch |9| which closes the circuit, thus energizing the solenoid |14 to shift the ejector control valve |10 upwardly to admit uid under pressure through the pipe 88 into the cylinder of a normally open limit switch 202 whichcloses a circuitv to energize a solenoid 203' which opensV the switch 200,. When the solenoid |14 of the valve |10 is energized, the solenoid |94 of the switch |83 which is kconnected in series therewith is also energized to withdraw the latch |85, and the released compression of thesprlng |84 opens the switch 83. 'I'his in turn deenerg'izes the solenoid |64 to allow the valve |60 to drop into its lower position, thus admitting fluid under pressure to withdraw the footstock center 62 from supporting engagement with the work just prior to the actuation of the ejector spindle 80 in ejecting the work piece 53 from the center 52.

It is desirable to provide means for stopping the grinding cycle at any time and returning the respective parts to their initial positions. In order to accomplish this result, a manually operable switch, suchl as a push button stop switch 205, is connected ln the electrical circuit so that in case the machine does not function properly, the circuit can be opened to immediately return the grinding wheel 45 to its rearward position.

A manually operable control lever 206 is pivotally mounted on a stud 201 which is in turn supported by a boss 208 projecting from the front of the machine base. When the upper end of the lever is moved toward the operator, the lower end of the lever operates the push button 8| to initiate a grinding cycle. If at any time during the grinding cycle, it is desirable to stop the grinding operation and remove the wheel from the work, the upper end of the lever.206 is moved toward the machine base which serves to actuate the push button switch 205 immediately to stop the grinding cycle.

The operation oi this machine is readily apparent from the foregoing disclosure. Assuming the parts to have been previously adjusted so that the desired grinding cycle may be obtained, a work piece 53 is placed in position on the work supporting cradle 90 (Fig. 2) and its frusto-conical end is moved into engagement with the female center 52. The control lever 206 is then shifted voutwardly'at its upper end to actuate the main cycle control push button |8| which closes a circuit to energize the solenoid |82 which closes the switch 83 and latches it in a closed position. Closing of the switch |83 energizes the solenoid |64 to shift the footstock valve |60 and admit fluid under pressure to cause the footstock center 82 to move into supporting engagef ment with the work piece. The shifting of the footstock center into an operative position serves to close the normally open limit switch 15 which closes a circuit to set the time delay relay |81 in operation. The relay |81 is connected so that when it is set in motion, the solenoid ||3 is energized to shift the feed control valve |02 to cause a forward feeding movement of the grinding wheel 45. The forward feeding movement continues for a predetermined time interval as governed by the time delay relay |81. When the predetermined time interval has elapsed, the solenoid ||3 is deenergized and the released tension of the spring shifts the feed control fluid under pressure to move the footstock center 62 to an inoperative position out of engagement with the work piece 53. The solenoid |14 is then energized to shift the valve |10 so as to admit fluid under pressure through pipe 8B into cylinder chamber 89 to shift the ejector rod 80 to eject the finish ground work piece 53 from the female center 52 onto the cradle. The finish ground work piece 53 may then be removed from the work supporting cradle 90 and replaced with a new work piece to be ground.

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

I claim:

l. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support thereon including a headstock and footstock each having a work supporting center, means including an electrical time delay relay to cause a forward and rearward movement of the wheel slide, manually operated electrically controlled means to move said footstock center to an operative position, and an electrical control actuated by movement of the footstock center to an operative position to initiate a forward feeding movement of the grinding wheel.

2. In a grinding machine having a rotatable grinding wheel, a transversely movable slidetherefor, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock each having a work supporting center, means including an electrical time delay relay to control the transverse movement of said wheel slide, a hydraulic piston and cylinder to move said footstock center toward and from an operative position, a manually operated electrically controlled means to .control said piston and cylinder so as to cause the footstock center to move to an operative position, means including an electrical switch actuated by movement of the footstock center to an operative position to initiate a forward feeding movement of the grinding wheel.

3. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock each having a work supporting center, a hydraulic piston andl cylinder to move said slide transversely, means including a electrical time delay relay to control the extent of the forward feeding movement of said slide, a hydraulic piston and cylinder to move said footstock center toward an operative position, a manually operated electrically controlled means to control said piston and cylinder so as to cause the footstock center to move to an operative position, and means including an electrical switch operated by movement of the footstock to an operative position to initiate a forward feeding movement of the grinding wheel.

4. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock each having a work supporting center, a hydraulically operated piston and cylinder to move said slide transversely, a control valve therefor, means including an electrically operated time delay relay to actuate said valve to initiate and control a grinding cycle, a hydraulically operated piston and cylinder to move said footstock center toward and from an operative position, a control valve therefor, a manually operated electrically controlled means to shift said valve to move the footstock center to an operative position, and means including an electric switch actuated by the movement of the footstcck center to an operative position to shift said feed control valveto initiate a forward feeding movement of the slide and to render said time delay relay operative so as to control the grinding cycle.

5. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable Awork support thereon including a headstock and a footstock each having a work supporting center, a hydraulic piston and cylinder to move the slide transversely, a control valve therefor, means including an electric solenoid to' actuate said valve to produce Va forward feeding movement of the slide, means including an electrically operated time delay relay to control the extent of forward movement of the slide, a hydraulic piston and cylinder to move said footstock center toward and from an operative position, a solenoid actuated valvetherefor, manually operated Aelectrically controlled means to actuate said solenoid valve to move the footstock center to an operative position, and means including an electric switch actuated by movement of said footstock center to an operative position to energize said solenoid and initiate a forward feeding movement of the grinding wheel and to set said timedelay relay in motion.

6. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support therein including a headstock and a footstock each having a work supporting center, a hydraulic piston and cylinder to move said slide, a. control valve therefor which is normally held in a position to cause a rearward movement of the slide, an electric solenoid to actuate said valve to initiate a forward feeding movement of the slide, an electrically operated time delay relay to control said solenoid, a hydraulic piston and cylinder to move the footstock center toward and from an operative posiion, an electric solenoid controlled valve therefor, a manually operated switch to control said .solenoid valve to actuate said footstock center,

and an electrical interlock between said wheel slide and footstock center whereby the wheel slide actuating mechanism is rendered inoperative until the footstock center has shifted into an operative position.

7. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock each having a work supporting center, a rotatable work rotating spindle in said headstock to support said headstock center, a work ejector slidably mounted within said cylinder, means including an electrical time delay relay to control the transverse movement of the wheel slide, a piston and cylinder to move said footstock center toward and from an operative position, a hydraulic piston and cylinder to actuate said ejector, means including a manually operable electrical control means for said footstock and ejector, and means including an electric `switch actuated by and in timed relation with the time delay relay to render the ejector operative to ejecta Work piece after a grinding operation has been completed.

8. Ina grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock each having a work supporting center, a rotatable Work rotating spindle in said headstock to support the headstock center, a Work ejector slidably mounted Within said spindle, a hydraulically operated piston and cylinder to move said wheel slide, means including an electrically operated time delay relay to con.-

trol the forward movement of the slide, a hy draulic piston and cylinder to move said footstock center toward and from an operative position, a solenoid actuated valve to control the admission of Iiuid to said cylinder, a hydraulic piston and cylinder to actuate said ejector, a solenoid actuated valve to control the admission of iiuid to said ejector cylinder, a manually operated electrically controlled means to actuate the footstock solenoid valve to initiate a movement of the footstock center to an operative posi- 'wheel slide, and electrically controlled means actuated by the time delay relay to operate said ejector solenoid valve to eject a work piece at the end of a grinding cycle.

CARL G. FLYGARE.