US2419133A - Grinding wheel feeding mechanism - Google Patents

Description

April 1947- J. l. GARSIDE GRINDING WHEEL FEEDING MECHANISM Filed July 28, 1945 IA l I I I swam/M .JUHN I. EARS/17E w, Mum M Patented Apr. 15, 1941 UNITED STATE GRINDING WHEEL FEEDING MECHANISM John I. Garsidc, -WestBoylston, Mass, assignor to Norton Company, Worceste ration of Massachusetts Application July 28.1945, serial No. 607,589

1 12 Claims.

This invention relates to grinding machines, and more particularly to a fluid pressure operated wheel feedingmechanism.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated wheel feeding mechanism for a grinding machine. Another object of the invention is to provide a semi-automatically controlled wheel feeding mechanism for a grinding machine in which the wheel may be first fed intermittently to round up the work piece, then at a slow continuous body grinding feed, and then allowed to dwell for apredetermined finish grinding or sparking-out period, after which the wheel is iaiutomatically returned to an inoperative posi- Another object of the invention is to provide an automatically operated gauge control which serves to stop the grinding feed when the work has been ground to a predetermined size and to set in motion a time delay relay which allows a sparking-out or finish grinding to continue for a predetermined time interval, after which the wheel is automatically and rapidly moved to an inoperative position. Other objects will be' in part obvious or in part pointed out hereinafter.

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

In the accompanying drawing, in' which is shown one of various possible embodiments of the mechanical features of this invention, is illustrated diagrammatically the improved hydraulically and electrically controlled wheel feeding mechanism, having some portions shown on an enlarged scale to clarify the illustration.

A grinding machine has been illustrated in the drawing comprising a base II) which supports a longitudinally movable work table I I on the usual fiat way l2 and V-way l3. The table II serves as a support for a headstock i4 and a rootstock (not shown) rotatably to support a work-piece IE to be ground.

A suitable traversing mechanism may be provided for longitudinally positioning the vork table ll so that the work piece is in the desired position for a grinding operation. This mechanism may comprise a rack bar !6 depending from the under side of the table I I. A gear ll meshes with the rack bar It and is mounted on the end of a shaft l8. The shaft i8 is rotatably journalled in suitable bearings (not. shown) which preferably comprises a 1-, Mesa, 9. corpoare fined relative to the base It). A manually operable traverse wheel is i mounted on the outer end of the shaft i8 by means of which the table II may be adjusted longitudinally relative to the baselil as desired.

A'rotatable grinding wheel 20 is supported at one end of a rotatable wheel spindle 2| which is journalled in suitable bearings (not shown) in a transversely movable wheel slide 22. The slide 22 is slidably supported on the usual flat way and V-way -(not shown) formed on the base II). A driving mechanism is provided for rotatin the grindig wheel 28 which may comprise an electric motor 23 which is mounted on the upper surface of the wheel slide 22. The motor 23 is provided with an armature shaft 24 which supports a multi-V-groove pulley 25. The multi-V- groove pulley 25 is connected by multiple V-belts 26 with a multi-V-groove pulley 21 which is mounted on the end of the wheel spindle 2!.

A suitable feeding mechanism is provided for adjusting the wheel slide 22 transversely relative to the base ll). This mechanism may comprise a rotatable cross feed screw 30 which meshes with a half nut 3i depending from the under side of the wheel slide 22. The feed screw 30 is slidably keyed at its left-hand end in a hollow sleeve 32 which is formed integral witha rotatable shaft 33. The shaft 33 is iournalied in suitable bearings (not shown) which are fixedly mounted relative to the base it). A manually operable feed wheel 34 is mounted on the front of the machine base and is operatively connected to rotate the shaft 33 and the feed screw to manually to adjust the position of the wheel slide 22 and the grinding wheel 20 as desired.

It is desirable to provide a suitable power operated mechanism for moving the wheel slide 22 rapidly to and from a grinding position and to aid in automatically controlling the grindingfeeding movement thereof. This mechanism hydraulic cylinder 35 which is supported in iixed relation with the 'base II). A slidably mounted piston 36 is mounted within the cylinder 35 and is operatively connected toa double end piston rod 31. The lefthand end of the piston rod 3'! is rotatably connected to a slidably mounted non-rotatable sleeve 38 which also rotatably supports the right-hand end of the feed screw 30. When fluid under pressure is admitted through a pipe 3 9 into a cylinder chamber 40 at the right-hand end of the piston 36, the piston 36 will move toward the left to transmit an axial feeding movement to the feed. screw 30 and a forward feeding movement to the grinding wheel slide 22 and the grinding wheel 28. During this movement, fluid within a cylinder chamber 4| formed at the lefthand end of the cylinder 35 exhausts through a pipe 42.

Control value to shift the valve 43 into its reverse position.

Dash pot-feed regulator A wheel feed regulator 55 is provided for retarding the rapid movement of the wheel slide 22 caused by the piston 36. This regulator 55 is preferably a dash pot type mechanism including a pair of dash pot pistons 56 and 51 which are arranged on diametrically opposite sides of the piston rod 31. Compression springs are provided normally to urge the dash pot pistons 56 and 51 toward the right. A sleeve 58 is adjustably mounted on the right-hand end of the piston rod 31. The sleeve 58 is provided with a flange 59 which may be formed integral with the sleeve 58 or may be formed in two parts, as indicated in the drawing. The flange 59 is arranged so that it will simultaneously engage both' of the dash pot pistons 56 and 5! when the piston rod 31 is moved toward the left. An adjustable stop screw 60 is provided to limit the rearward movement of the flange 59 toward the right and thus determine the inoperative positionof the dash pot pistons 56 and 51. An adjustable collar 6| is threaded onto a threaded portion 62 of the piston rod 31. This collar 6! is adjusted so that when the piston 36 has moved to a predetermined position in its stroke so that the grinding wheel 20 is about to engage the work piece to be ground, the collar 6| will engage the sleeve 58 and thereby start movement of the dash pot pistons 56 and 5'! toward the left. Fluid within the dash pot chambers is thereby compressed and forced out through a passage 63, a needle valve 64, and a pipe 65 into a reservoir 66. By adjusting the needle valve 66, the speed of the feeding movement imparted to the grinding wheel 28 may be varied as desired.

In certain grinding operations, it may be desirable to cut off the exhaust of fluid through the pipe 65 thereby to stop the forward feeding movement, as controlled by the needle valve 64, automatically in timed relation With the movement of other parts of the grinding wheel feeding mechanism to be hereinafter described. To accomplish this result, a piston type valve 67 is provided the feed control valve 43. An adjustable pressure relief valve 14 is provided in the pipe line 73 which serves to exhaust excess fluid under pressure directly into the reservoir 12 so as to maintain the desired operating pressure within the hydraulic system.

Fluid under pressure passing through the pipe 13 enters a valve chamber 15 located between the valve pistons 46 and 41 of the feed control valve 43. In the position of the valve 43 as illustrated, fluid under pressure entering the valve chamber 15 passes out through the pipe 42 into the cylinder chamber 4! to move the piston 36 toward the right into an inoperative position. During this movement, fluid within the cylinder chamber 40 exhausts through the pipe 39, through a valve chamber l6 located between the valve pistons 45 and 46, and passes out through an exhaust pipe 11 which conveys exhaust fluid back to the reservoir 12. A throttle valve 16 is provided in the pipe line 11 by means of which the rate of exhaust of fluid from. the feed control valve 43 may be readily controlled to regulate the speed of movement of the grinding wheel and its supporting slide 22 to a rearward position.

Displacement Cylinder In a plunge-cut grinding operation it is desirable to provide an intermittent rather than in the pipe line between the needle valve 66 and the reservoir 66. The valve 57 is a normally open valve and is normally held in the position illustrated in the drawings by means of a compression spring. An electric pull-type solenoid 68 is pro vided automatically to close the valve 6! when the solenoid 66 is energized in a manner to be hereinafter described.

Fluid system A fluid pressure system is provided for supplying the desired fluid under pressure for the operating mechanisms of the machine comprising a a, continuous infeeding movement of the grinding wheel so that the grinding wheel 20 may be advanced by a predetermined amount and the grinding wheel allowed to grind the work piece l5 being ground before the wheel 20 is again advanced. It has been found that by such a feeding mechanism, the work may be more readily rounded-up to a precise cylindrical form and size. In order'to provide a relatively slow infeeding movement of the grinding wheel which may be operated either continuously or intermittently, it is desirable to provide a suitable control mechanismwhereby fluid exhausting from the dash pot cylinders may be readily controlled as desired. In the preferred construction, a displacement cylinder 38 is provided having a longitudinally movable displacement plunger 8| contained therein.

The plunger 8! is preferably actuated hydraulically by means of a piston 82 which is slidably mounted in a cylinder 83. A pipe 84 connects the dash pot cylinder chambers with the displacement cylinder 88 so that as the displacement plunger M is moved toward the left, the capacity of the displacement cylinder 89 will be increased, thereby allowing a predetermined amount of fluid to pass from the dash pot cylinder chambers into the displacement cylinder til, thus allowing the grinding wheel 28 to move forward under the pressure applied to the piston 36. By controlling the rate of movement of the displacement rod M, the rate of feeding movement of the grinding wheel 25 may be readily varied as desired. Ii? the displacement rod Qi is moved at a slow continuous rate toward the left, a slow precise continuous infeed of the grinding wheel 28 may be obtained. If the rod Si is moved intermittently toward the left at slow intervals, a slow intermittent precise feeding movement of the grinding wheel 28 may be obtained.

The cylinder 83 is preferably connected so that the piston 82 will be actuated in timed relation with the actuation of the feed control valve 43. A

to close the valve ing valve I88 which comprises a tle type valve I82 is respectively with the exhaust pipe pipe 88 connects the valve chamber I8. with a chamber '88 formed at the right-hand end of the position of the valve 43 shown in the drawing, fluid within the cylinder chamber 88 may exhaust through the pipe, through the valve chamber 16, and through the pipe 11 into the reservoir 12.

A pipe 81 is connected between the valve 43 and a check valve 88." The check valve '88 is connected by a pipe 89 with a cylinder chamber 98 formed at the left-hand end of the cylinder 83. In the position of the control valve 43 illustrated in the drawings, fluid under pressure in the valve chamber I may pass through the pipe 81, through the check valve 88 and the pipe 89 into the cylinder chamber 98 to move the piston 82 into the position illustrated in the drawing.

During the forward, movement of the grinding wheel 28, it is desirable to control the rate of exhaust of fluid from the cylinder chamber 98 so as to provide the desired continuous rate of infeeding movement when desired. A pipe III is connected between the pipe 89 and a piston type valve 92 which is normally held in an open position by means of a compressionspring. A pull type solenoid 93 is provided automatically 92 when desired in timed relationship with other mechanisms of ,the machine when it is desired to cut oi the exhaust of fluid through the pipe 9 I An adjustable throttle valve 9| is provided in a pipe line 95 which connects the throttle valve 94 with the pipe 81. When fluid exhausts through the valve 92 and the throttle valve 94, it passes through the pipe 95 and the pipe 81- into a valve chamber 96 formed between the valve pistons 81 and 48 when the valve stem 44 is in its left-hand end position and passes out through the exhaust pipe 'I'I into the reservoir 12.;

cylinder 83. In the Metering valve It is desirable during portions of the grinding operation to provide an intermittent flne precise feeding movement of the grinding wheel 28. This is preferably accomplished by means of a meterhollow slidablymounted piston-type valve member I8I. A shutslidably mounted within the valve member. IN. The valve member IN is preferably actuated automatically by means of a piston rod I83 ed collars I85 and and a pair of adjustably mountl85 in a manner to be hereinafter described. 1 An adjustable stop screw I86 is provided which is-screw threaded into an end cap I81 which encloses the left-handend otthe valve member I84 The screw I86 serves to limit the movement of the shuttle valve I 81 and thereby to regulate the amount-of exhaust metered from the cylinder chamber 98 of the cylinder 93. A pipe I88 connects the pipe 89' with ports I89 and H8 in the valve I88. A pair of exhaust ports III and i I2 are connected by pipes '11. When an intermittent feed of the grindin matically in a manner to be hereinafter described so that fluid under pressure exhausting from the cylinder chamber-'98 exhausts through the pipe '89, through the pipe I88, into the ports I89 and H8. The valve stem I83 is shown in its extreme the left automatically in a member 'I8I will move toward the left until a H3 and Ill wheel 28 is desired, the valve 92 is closed auto'.

right-hand end position. When the valve stem v I83 is moved toward manner to be hereinafter described, the valve port I I! coincides with the port II8 so that fluid may exhaust from a valve chamber I I8 to move the shuttle valve I82 I toward the left into-engagement with the stop "ment of the shuttle valve screw I88. This movement allows a predetermined quantity of fluid to exhaust from the chamber 98, thereby allowing a predetermined movement of the displacement rod 8| which allows a predetermined forward feed of the grinding wheel 28. v

The valve I88 is illustrated on an enlarged scale to clarify the construction as compared with the cylinder .88 and associated parts. During the exhaust of fluid into the valve chamber IIB, a portion of the fluid within a chamber I I1 exhausts through a port I I8 and the port I I I, through the pipe I I3 and the exhaust pipe 'I'I, into the reservoir I2. It should be noted that only enough fluid is exhausted from the chamber III to take care of the displacement caused by the move- I82 toward the left. A similar operation is provided when the valve stem I83 again moves toward'the right into the position illustrated in the drawings. A predetermined quantity of fluid will be metered from the cylinder chamber 98 into the valve chamber III to move the shuttle valve I82 toward the right, thus allowing a predetermined infeed of the grinding wheel 28,by a predetermined movement of the displacement rod 8I.

Fluid motor I I9 is identical with that shown in the prior U. S.

patent to Wallace H. Wood, No. 2,212,871, dated August 27, 1940, to which reference may be had for details of disclosure not contained herein. The motor II9 comprises a cylinder I28 which contains a slidably mounted piston I2 I The piston I2I is connected to the right-hand end of a piston rod I22. A yoked member I23 is provided on the left-hand end of the piston rod I22 which straddles the valve stem I83 and is arranged in the path of the collars I88 and I85. A suitable control valve is provided automatically to reciprocate the piston I2I continuously, comprising a valve stem I26 which is fixedly mounted relative to a hollow slidably-mounted piston-type pilot valve I25. A shuttle type reversing valve I28 is slidably mounted within the hollow pilot valve I25. The valve stem I26 of the pilot valve I25 is provided with a pair of adjustably mounted collars I21 and I28 which are arranged to engage an upwardly extending portion I29 of the yoked member I29. The collars I21 and I28 are actuated by movement of the piston Hi to determine the length of the stroke of the piston I2I. This motor H9 is arranged automatically to transmit a reciprocatory motion to .the yoked member I23 which in turn serves to actuate the metering valve -I88 in a, manner hereinabove described.

A normally closed valve I38 is provided to control the admission of fluid under pressure to the motor H9. .The control valve I38 is normally held in a downward or closed position by means of a compression spring. An electric solenoid I3I is provided which when energized will raise the valve to admit fluid under pressure from the pipe I3 into a pipe I32 whichadlnits fluid under pressure to the pilot valve I25 so as to start and continuously reciprocate the piston I2I. Fluid exhaust the cylinder chamber 98 into to provide an automatic intermittent from the motor H9, through a pipe 533, and through an adjustable throttle valve i243, into the exhaust pipe ll, and returns to the reservoir l2. By adjustment of the throttle valve H36, the speed of.reciprocatory movement of the piston l2i may be readily controlled so as thereby to control the rate of actuation of the metering valve 800 and thus provide either a, slow intermittent or a rapid intermittent feeding movement of the grinding wheel as desired.

To facilitate filling the dash pot cylinders and the reservoir 66, a valve M is connected'in the pipe line l3 which when open may pass fluid through a pipe MI and a ball check valve I42 into the dash pot cylinders and also through a pipe I66 into the reservoir 66. The valve I40 is utilized only when it is necessary to replenish fluid in the dash pot system.

Gauge head In order precisely to control the work size, a gauging mechanism is preferably provided such as that, for example, shown in the patent to Shubel A. Foster, No. 2,267,559, dated December 23, 1941, to which reference may behad for details of disclosure not contained herein. As shown in the drawing, this gauging device comprises a caliper I45 which is pivotally supported on a pivotally mounted bracket I46. One end of the bracket I46 is pivotally mounted on a wheel guard I41 which surrounds the grinding wheel 20. The caliper I45 is arranged to be swung from an inoperative position, as shown in the drawing, in a clockwise direction, then downwardly, and then in a counterclockwise direction into operative engagement with the work piece I being ground. When the work piece has been reduced to a predetermined size, electric contacts I48 within the caliper head are made to close a circuit which serves to energize a relay I49 which is operatively connected to energize the solenoid 93 and thereby close the valve 02 and thus stop the continuous infeed or body feed of the grind-- ing wheel 20 into the work I5 and at the same time serves to start a time delay relay I50.

Time relay The time delay relay I50 is a standard electrical relay such as, for example, the Microfiex automatic instantaneous reset timer manufactured by the Eagle Signal Corporation of Moline, Illinois. When the time relay I50 timing the period of dwell during which there is no infeed of the grinding wheel 20 has completed a predetermined time interval, the time delay relay I50 serves to break a circuit and thus deenergize the solenoid 50, thereby releasing the compression of the spring 69 which returns the feed control valve 63 into the position illustrated in the drawing, thus admitting fluid under pressure into the cylinder chamber 4I of thecylinder 35 rapidly to move the piston 36 together with the wheel slide 22 and grinding wheel 20 toward the right into an inoperative position.

A manually operable control lever H55 is provided for starting a grinding cycle or, if necessary, stopping the grinding cycle during a grindlng operation in case of emergency. The control lever I55 is pivotally mounted on astud 56 and is arranged so that when rocked in a counterclockwise direction, it will close a push button switch I5? to start a grinding cycle. If it is desired to stop the grinding operation during a grinding cycle, the control lever H55 ma be rocked in a clockwise direction to close a push to deenergize the relay I62.

button switch 852 which interrupts the grinding cycle and immediately and automatically returns the grinding wheel and its supporting slide to an inoperative position.

Operation The operation of thisimproved feeding mechanism will be readily apparent from the foregoing disclosure. Assuming all of the adjustments have previously been made and a work piece I5 has been loaded in an operating position ready for a grinding operation, the operator rocks the control lever E55 in a counterclockwise direction to close the push button start switch I51. This movement energizes a relay I60 which in turn serves to energize the solenoid 50 toshift the valve stem 40 of the feed control valve 43 toward the left to admit fluid under pressure into the cylinder chamber 60 rapidly, to move the piston 36, the wheel slide 22, and the grinding wheel 20 toward the left so that it approaches the work piece I5. Before the grinding wheel 20 engages the work piece I5, the flange 59 engages the dash pot pistons 56 and 51 so that continued forward advance of the wheel is slowed down to a cushioning or shoulder feed in the case of a shoulder grinding operation, the speed of which is governed by the setting of the needle valve 64. The grinding wheel continues to advance at the cushioning feed or shoulder grinding feeduntil the screw 5| engages and closes the limit switch 52. The closing of the limit switch 52 serves to energize a relay I 6| and a relay I62. Energizing of the relay I6I serves to energize the solenoid 68 to close the valve 61, thus stopping the cushioning or shoulder grinding feed. Energizing of the relay I62 serves to energize the solenoid 93 to close the valve 92, thereby preventing passage of oil therethrough so as to prevent a body grinding feed being obtained. Energizing of the relay I62 also energizes the solenoid I3I to open the valve I30 which allows passage of fluid under pressure through the pipe I32 to start the continuous reciprocation of the piston I2I which in turn serves intermittently to actuate the metering' valve I00. The metering valve I00 allows an intermittent exhaust of a predetermined amount of fluid from the cylinder chamber of the cylinder 83 which in turn withdraws the displacement plunger 8| a predetermined amount to produce an intermittent advance of the grinding wheel by allowing a periodic predetermined quantity of fluid to exhaust from the dash pot cylinders through the pipe 84 into the displace ment cylinder 80.

The gauge head I45may now be placed in operative position in engagement with the work piece l5. The intermittent feed of the grinding wheel continues'until the screw 53 engages and opens the limit switch 54 which opens a circuit Deenergizing the relay I62 serves to deenergize the solenoid I3i.

thus allowing the released compression of a spring to close the valve I30 to stop the intermittent infeed of the grinding wheel. At the same time, deenergizing the relay I62 serves to deenergize the solenoid 93, thus allowing the released compression of a spring to open the valve 92 to start a fine continuous body feed of the wheel toward the work axis by allowing fluid to exhaust from the cylinder chamber 90, through the pipe 9i, through the valve 92, and through the throttle valve 94 at a relatively slow rate. thuscausing a further continuous movement of enigma until the work has been reduced to a predeter mined size at which time. the contacts Its in the gauge I45 close to energize the relay I49. Energizing the relay I49 serves to energize the solenoid 93 to close the valve 92 and thereby shut ofi the body feed of the grinding wheel 22. At the same time, energizing of the relay I49 sets the time delay relay I50 in motion to control the sparking-out or finish grinding or the work piece I while the wheel 2!! is held against further forward feeding movement. The finish grinding or sparking-out period continues for a predetermined time interval as gove ned by the relay I50. After the predetermined time interval has elapsed, the time relay I50 deenergizes the relay I60 which in turnserves to demergize the solenoid 5Il,'-thereby releasing the compression of the spring 49 which in turn moves the valve stem 48 toward the right to position the valve parts in the position shown in the'drawing. This shifting movement of the valve 63 serves to pass fluid through the pipe 42 into the cylinderchamber 4I rapidly to move the piston 36, the grinding wheel slide 22, and the grinding wheel 20 toward the right into a rearward or inoperative position,-thus terminating the grinding cycle. a p

when the timer I59 operates to deenfergize the relay limit also is 'operatively connected to deenergize the'relays I49 and IBI respectively. Deenergiaingof'the relays I49 and IGI serves to deenergiz'ethe solenoid 68 and the solenoid 93 to open thevalves 61 and 92 respectively. Th gauge is then removed from engagement with thework' and the gauge contacts are automati cally'broken or reset for the next grinding operationand the electric timer I5Ii automatically resets ready for the next grinding cycle. The

finish ground work piece I5 may then be removed from the machine and replaced by anew work iece tobe ground, after which the next grinding cycle may be initiated by actuation of the control lever I55 in a manner hereinab'ove d'escribe'd.-

It will thus be seen that-there has been prof therefor, means including a pisten and cylinder rapidly to move said slide, means including a dash I pot feed regulator to slow down the rapid appreaching to a relativel slow continuous feedin movement for a shoulder grinding operation, electrical control means rendered operative after a predetermined slow feed intermittently to produce a fine intermittent body feed, to round up the cylindrical surface being ground, a work sizing gage automatically to stop the forward feed for a predetermined time interval, and an electrical time delayrelay operatively connected to return said slide and grinding wheel to an inoperatfi'e position after a predetermm' ed period of 3. In a grinding machine having a rotatable grinding wheelna transversely movable slide 1 therefor, meansIin'cluding a piston and cylinder rapidly to move said slide; means including a, dash pot feed regulator to slow down the rapid approaching to a relatively slow continuous feeding movement, means rendered operative after the wheel reaches a predetermined position intermittently to exhaust fluid from said regulator to produce a fine intermittent feed of the grinding wheel, means to control continuous exhaust fluid from said regulator to produce a fine continuous plunge-cut feed, means automatically to stop said feed for a predeterminedtime interval, and an electrical time delay relay operatively connected to return said slide and wheel to an inoperative position after said time interval has elapsed,

4. In a grinding machine having a rotatable 'grinding wheel, a transversely movable slide .movement for a shoulder grinding operation,

means rendered operative after the wheel reaches a predetermined position intermittently to ex haust fluid from said regulator .to produce a fine 1 intermittent feed of the grinding wheel to round up the cylindrical surface being ground, means to vided 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's'et forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a, limiting sense.

Iclaimz. g 1. In a grinding machine -'having a rotatable grinding wheel, a transversely movable slide,

therefor, means including a piston and cylinder rapidly to move said slide, means including a dash pot feed regulator to slow down the rapid approaching to a relatively slow continuous feed mg movement, electrical control means rendered operative after a predetermined slow feed intermittently to produces. fine intermittent feed to round up the surface being ground, meansto stop the forward feed for a predetermined time interval, and an electrical time delay relay operatively connected to return said slide and grinding wheel to an inoperative position after a, predetermined period of dwell.

2. In a grinding machine having a rotatable grinding wheel, a tersely movable slide control continuous exhaust of fluid from said legulator to produce a fine continuous plunge cut feedto reduce said surface to a predeteed size, means automatically to stop said feed for a predetermined time interval, and an electrical time delay relay operatively connected to return said slide and wheel to an inoperative position after said time interval has elapsed.

5. Ina grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, means including a piston and cylinder rapidly to move said slide, a. control valve therefor, means including a dash. pot feed regulator to slow down the'rapid approaching to a relatively 'slow shoulder grinding feed, means to intermit= tently exhaust fluid from said regulator to pro duce a, fine intermittent feed to round up the work, means continuously to exhaust fluid] from said regulator to produce a fine continuous feed 6. In a grinding machine having a rotatable emise minding wheel, a transversely movable slide therefor, means including piston and cylinder rapidly to move said slide, a control valve therefor, means including a dash pot feed regulator to slow down the rapid approaching to a relatively slow shoulder grinding feed, means intermittently to exhaust fluid from said regulator to produce a fine intermittent feed to round up the work, means continuously to exhaust fluid from said regulator to produce a flne continuous feed of the grinding wheel relative to the work, means auto matically to stop said continuous feed when the work has been reduced to a predetermined extent, a time delay relay which is set in motion when the continuous feed is stopped while maintaining th grinding wheel in grinding engagement with the work for a predetermined finish grinding period, and means actuated by said relay after a predetermined time interval to shift said control valve and thereby terminate the grind ing operation. 7. In a grinding machine as claimed in claim 5, the combination with the parts and features therein specified, of a displacement cylinder and rod to control the exhaust of fluid from said dash not feed regulator, a hydraulic piston and cylinder to actuate said displacement rod so as to increase or decrease the capacity of said displacement cylinder, means intermittently to exhaust a predetermined amount of fluid from said hydraulic cylinder intermittently to move said displacement rod so as to produce a feeding movement of the grinding wheel, and means including a throttle valve continuously to exhaust fluid from said hidraulic cylinder continuously to move said displacement rod so as to produce a fine continuous infeed of the grinding wheel.

8. In a grinding machine as claimed in claim 5, the combination with the parts and features therein specified, of means including a displace-,

ment cylinder and rod to control the rate of exhaust of fluid from said dash pot feed regulator, a hydraulic piston and cylinder to actuate said placement rod so as to increase or decrease the capacity of said displacement cylinder, means including a metering valve to meter the exhaust of fluid from said hydraulic cylinder, a continuously actuated fluid motor to actuate said metering valve to provide an intermittent infeed of the rinding wheel, and a normally open solenoid valve to start and stop said motor.

9. In a grinding machine as claimed in claim 5, the combination with the parts and features therein specified, of means including a displacement cylinder and rod to control the exhaust oi fluid from said dash pot feed regulator, a hydraulic piston and cylinder to actuate said displacement rod so as to increase or decrease the capacity of said displacement cylinder, 2, metering valve to meter the exhaust of fluid from said hydraulic cylinder, means including a continuously actuated fluid motor to actuate said metering valve so as intermittently to move said displacement rod to pr uce an intermittent feed of the grinding wheel, a solenoid valve to start and stop said motor, means including a solenoid valve to start and stop the continuous exhaust of fluid from said cylinder, and means including a throttle valve to regulate said continuous exhaust of fluid from the hydraulic cylinder to produce the desired continuous infeeding movement of said grinding wheel.

10. In a grinding machine as claimed in claim 5, the combination with the parts and features therein specified, of means including a displaceing valve to meter the exhaust of fluid from said.

- hydraulic cylinder, means including a continuously actuated fluid motor to actuate said metering valve so as intermittently to move said dis-.-

l placement rod to produce an intermittent feed of the grinding wheel, a normally closed solenoid valve to start and stop said motor, means including a normally open solenoid valve to start and stop the continuous exhaust of fluid from said cylinder, and means including a throttle valve to regulate said continuous exhaust of fluid from the hydraulic cylinder to produce the desired continuous infeeding movement of said grinding wheel. J

11. In a grinding machine as claimed in claim 5, the combination with the parts and features therein specified, of means including a displacement cylinder and rod to control the exhaust 01' fluid from said dash pot feed regulator, a hydraulic piston and cylinder to actuate said displacement rod so as to increase or decrease the capacity of said displacement cylinder, a metering valve to meter the exhaust of fluid from said hydraulic cylinder, means including a continuously actuated fluid motor to actuate said metering valve'so as intermittently to move said displacement rod to produce an intermittent feed of the grinding wheel, a normally closed solenoid valve to start and stop said motor, means including a throttle valve to regulate the continuous exhaust of fluid from'the hydraulic cylinder to produce the desired continuous infeeding movement of said grinding wheel, means including a normally open solenoid valve to start and stop con- 40 tinuous exhaust of fluid from said hydraulic cylinder, and electrical control means simultaneously to actuate said solenoid valves so as to render operative either an intermittent or a continuous feed of the grinding wheel.

12. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, means including a piston and cylinder rapidly to move said slide, a solenoid actuated control valve therefor, means including a dash pct feed regulator having a needle valve to slow down the rapid approaching to a relatively slow shoulder grinding feed, a solenoid valve to cut oil fluid exhausting through said needle valve to stop the shoulder grinding feed, a limit switch actuated by movement of said piston, an electric relay operatively connected with said switch and solenoid valve to close the solenoid valve when the limit switch is closed, means including a solenoid valve to start and stop an intermittent feed of the grinding wheel to round up the work, means including a solenoid valve to start and stop a continuous infeed of the wheel to size the work, a second relay which is actuated by the closing of said limit switch to actuate the second and third 5 solenoid valves o as automatically to start an intermittent feed of the grinding wheel when the shoulder grinding feed is terminated to' round up the work, a limit switch which is opened after a further continuous feeding movement to actuate the second and third solenoid valves to terminate the intermittent feed and to start a fine continuous feed, a work gauging device including a normally open switch which is closed when the work is ground to a predetermined size, a relay actuated thereby to terminatesaid continuous feed,

- 2 2 and an electfical time delay reley which is eet in e mehien by clbsmg said gauging device ewitch te central the duration of a, predeizermined finish grindingnoperation, said time relay after e pre determined time interval serving to deenergize said seleneid control valve to cause e reerwerd mevement of the grinding wheel and thus termi a, grinding cycle.

JOHN E. mmemm The fellewmg reiferencee ere ef xrecerd in the file of this patent:

eemaee Number 2,082,?26 5 2,113,361 2,1163% 2,1.'-2,02E% 2,267,391 zgeemee m 2,37%,237

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