US2448921A - Hydraulically operated feeding mechanism - Google Patents

Description

Sept. 1948- H. A. SILVEN 2,448;921 H'YDRAULICALLY orsnnsn Famine MECHANISM Filed Nov. 1, 1946 HERBERT A. SILVEN -Fatented Sept. 7, 1948 mummy oramrrsn resume.

MECHANISM Herbert A. Bllven, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application November 1, 1946, Serial No. 707,214

8 Claims. I

The invention relates to grinding machines and more particularly to a grinding wheel feeding mechanism.

One object of the invention is to provide a simple and thoroughly practical grinding wheel feeding mechanism.' Another object of the invention is to provide a hydraulically operated wheel feeding mechanism which is arranged to cause a rapid approaching movement of the grinding wheel, then a slow shoulder grinding feed of the wheel until the grinding wheel engages the peripheral surface of the work at which time the infeed is automatically reduced to a slower uniform body feed. Another object of the invention is to provide a wheel feeding mechanism in which a feeler actuated mechanism automatically changes the rate of infeed when the periphery of the grinding wheel engages the body portion of the work to be ground regardless of the initial diameter of the body portion. Another object of the invention is to provide a wheel feeding mechanism in which the rapid approaching or shoulder feed of the grinding wheel continues until the periphery of the grinding wheel engages the cylindrical body portion of the work at which time the feed is automatically reduced to a predetermined and uniform grinding feed. Another object of the invention is to provide a wheel feeding mechanism with a control means which is governed by the diameter of the work being ground for automatically changing the rate of infeed to a predetermined grinding feed when the grinding wheel engages the periphery of thework piece.

Another object of the invention is to provide a hydraulically actuated electrically controlled feeding mechanism in which a work engaging feeler and control means governed thereby automatically changes the rate of feed of. the grinding wheel to a grinding-feed when the grinding wheel moves into engagement with the work piece being ground. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

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

Fig. 1 is a diagrammatic showing of the hydraulically actuated electrically controlled grinding wheel feeding mechanism.

A grinding machine has been illustrated in the drawings comprising a base 8 which supports a transversely movable grinding wheel slide it on the usual V-way and flat way (not shown). The wheel slide ill serves as a'support for a rotatable grinding wheel Ii. A rotatable work support is provided for rotatably supporting a work piece I! in order that its peripheral cylindrical surface may be ground. The work support has not been illustrated since it is not considered to be a part of the present invention. A conventional work support comprising a head stock and a footstock may be utilized such as for example that shown in the expired U. S. patent to C. H. Norton, No. 762,838 dated June 14, 1904, to which reference may be had for details of disclosure not contained herein.

The wheel slide in is provided with a dependin half nut II which meshes with or engages a rotatably mounted feed screw H. The right hand end of the feed screw It is supported in a slidably mounted bearing IS. The screw it may be rotated by the old and well known manually operable cross feeding mechanism such as for example that shown in the above mentioned expired U. S. patent.

In order to feed the grinding wheel toward and from the work piece, a hydraulically operated mechanism is provided comprising a cylinder it which is fixedly mounted in the base 9. The cylinder It contains a slidably mounted piston 11 which is connected to a double end piston rod it. The left hand end of the piston rod I8 is operatively connected to the slidably mounted bearing l5. As illustrated in the drawings, the hydraulic cylinder iii, the piston i1, and the piston rod l8 are arranged in axial alignment with the feed screw I4. When it is desired to move the grinding wheel to a rearward or inoperative position such as that shown in the drawings, fluid under pressure may be admittcd through a pipe i9 into a cylinder chamber 20 to cause the piston i1 and associated parts to move toward the right into the position illustrated in the drawing. During this movement of the piston l'l, fluid within a cylinder cham- -bcr 2i may be exhausted through a pipe 22.

Similarly, when it -is desired to cause a forward feeding movement of the grinding wheel, fluid under pressure may be admitted through the pipe 22 into cylinder chamber 2| to cause the piston II to move toward the left and thus transmit a corresponding movement through piston 'rod l8, the slidably mounted bearing ill, the feed screw II, the half nut "(and the wheel slide 3 a II to cause the wheel H to approach the peripheral surface of the work piece 42. During this movement of the wheel slide l0, fluid within the cylinder chamber 20 may be exhausted through the pipe l8.

A fluidpressure system is provided comprising a reservoir 25. A motor driven pump 28 draws fluid through a pipe 21 from the reservoir 24 and passes fluid under pressure through a pipe 28 to a control valve 28. The control valve 22 is preferably a piston type control valve comprising valve stem 30 having formed integrally therewith a plurality of valve pistons ll. 32, II and 24. The valve stem 30' is normally held in its right hand and position by means of a compression spring 38 which surrounds the valve stem 20 and is interposed between the end face of the valve casing 28 and a flange 34 which is either formed integral or fixedly mounted on the valve stem 30. In the position of the valve as shown in the drawings, fluid under pressure passing through the pipe 28 enters a valve chamber located between the valve pistons 32 and II and passes out through the pipe l8 into the cylinder chamber 20 to cause the Piston I! to move toward the right into the position illustrated in the drawings. During this movement of the piston l'I, fluid within the cylinder chamber 2i may exhaust through the pipe 22 into a valve chamber located between the valve .pistons 2i and 32 and pass out through an exhaust pipe I88 into the reservoir 25.

In the preferred construction, the valve 25 is arranged to beautomatically shifted into a reverse position to change the direction of flow of fluid under pressure by means of an electric solenoid 31. When the solenoid 31 is energized, in a manner to be hereinafter described, the valve stem 30 will be shifted toward the left against the compression of the spring is so that fluid under pressure passing through the pipe 28 will enter the valve chamber located between the valve pistons 32 and 33 and pass outwardly through the pipe 22 into the cylinder chamber 2| to cause an infeeding or approaching movement of the grinding wheel slide iii and the grinding wheel I I.

- In order to control the energization of the forward feeding movement at any time it is desired and thereby deenergizing the solenoid 31 'so that the released compression of the spring 35 will shift the control valve into the position illustrated "in the drawings thereby causing the wheel slide l and the grinding wheel ii to move to a rearward or inoperative position. A manually operable control lever 43 is pivotally supported on a stud 44 which is.preferably supported in fixed relationship with the base 8. The control lever 43 serves to facilitate manual actuation of the switches '4i and 42. It will be readily apparent from the foregoing disclosure that when the control lever 43 is rocked in a I counter clockwise direction, the starter switch 4i will be closed to initiate a forward feeding movement. Similarly. if the control lever 43 1 rocked in a clockwise direction, the stop switch 42 will be opened so as to deenergize the relay switch 44 and thus cause the control valve to shift to cause the wheel slide is and grindin 1 mined position. This regulator comprises a pair of dash pot pistons II and '2 arranged on diametrically opposite sides of the piston rod II- This dash pot feed regulator is substantially the same as that shown in the prior U. 8. Patent to W. H. Wood, No. 2,082,728, dated June 11, 1937, to which reference may be had for details of disclosure not contained herein. The dash pot pistons II and 42 are normally urged in a right hand direction by a pair of compression springs I3 and 44 which serve to return the dash pot pistons II and II to inoperative positions when the grinding wheel ii is moved rearwardly to its inoperative position. A flanged collar II is ad- Justably mounted on a rearwardly extending portion II of the piston rod ll.

The rapid approaching movement of the grinding wheel ii continues until the flanged collar 8! engages the ends of the dash pot pistons 5i and i2 and moves them toward the left.

This movement serves to exhaust fluid from the dash pot cylinder chambers through a passage Bi and through a needle valve 58. By regulating the needle valve 88, the exhaust of fluid from the dash pot cylinders may be regulated so as to 5 produce the desired feed.

Fluid exhausting through the needle valve ll passes through a pipe I! and through a throttle valve 60 and a pipe 6| which returns the exhausting fluid to the reservoir 2!. In certain types of grinding operations it is desirable to provide not only a rapid approaching but also a slow shoulder grinding feed and then a slower uniform feed during the grinding of the peripheral body portion of a work piece. In order to 45 provide the desired control of the exhausting fluid so as to obtain the different feeds desired, a normally open solenoid valve 62 is provided comprising a valve chamber '2. Fluid passing through the pipe II may pass through the chamher 82 and out through a pipe 84. through a second throttle valve 25 and through the pipe 4i into the reservoir 25. A compression spring 46 serves normally to maintain the valve in an open position. A solenoid 41 is provided which, when energized, causes an upward movement of the valve parts to close the valve and thereby to prevent fluid passing from the pipe I! through the pipe 84.

As illustrated in the drawings, the shoulder grinding feed is determined by the'setting of the needle valve 52, the throttle valves Oil and II. When it is desired to change from a shoulder grinding feed to a body grinding feed, the solenoid 41 is energized to close the valve 03 so that as fluid exhausting from the feed regulator ll through the pipe 50 may pass only through the throttle valve 40. The throttle valve I being cut off by the closing of the solenoid valve 43.

By manipulation of the throttle valve 00, the desired and predetermined body grinding feed may be obtained.

In order to refill the dash pot cylinders during the rearward movement of the grinding wheel ll so that the feed regulator will be in condition for the next grinding op ration, a pipe I8 is conramps:

valve 88, through a pipe 18 into the pipe 88.

It will be readily apparent from the foregoing disclosure that in the position of the valves as shown in the drawing. fluid under pressure passing through the pipe I8 will pass through the pipe 88, through the check valve 88, the pipe III, the pipe 88, through the needle valve 58, the passage 81 into the dash potcylinders to'positively move the dash pot pistons 8| and 82 toward the right and at the same time serving to fill the dash pot cylinder chambers for the next infeeding operation.

In order to provide an extremely efficient wheel feeding mechanism, it is desirable that the solenoid valve '88 be automatically closed when the grinding wheel II is about to engage the work piece I2 automatically to change from a shoulder to a body grinding feed. Due to the fact that the initial size of the work pieces to be ground frequently varies, it is desirable to provide a suit-. able mechanism whereby the shift from shoulder to body feed occurs when the wheel II engages the periphery of the work piece l2 regardless of the initial size of the work piece H. In the preferred construction, a work engaging feeler actuated mechanism is provided for controlling the shifting of the feeding mechanism. This preferably comprises a pivotally mounted feeler arm 18 which is adjustablemounted on a rock shaft 18. The rock shaft I8 is supported by a bracket 11 on a conventional type work table 18. The feeler arm I8 is provided with a work engaging roller.

I8. A compression spring 88 is provided for normally maintaining the roller" in operative engagement'with the work piece I2 to be ground. A clamping screw BI is provided to facilitate adjustment of the feeler arm 18 relative to the rock shaft I8 in setting up the machine for a given grinding operation. The rock shaft I8 also supports a rock arm 82. The rock arm 82 is preferably pinned to the shaft so that the feeler arm I8 and the rock arm 82 when adjusted act as a bell crank lever. The left handend of the rock arm 82 supports a normally open limit switch 83 having an actuating plunger 84. The limit switch 88 is electrically connected so that when closed, it serves to energize the solenoid 81 andthereby close the solenoid valve 88.

A suitable fluid pressure mechanism is provided for controlling the actuation of the limit switch 88. This mechanism comprises a normally closed solenoid valve 88. The valve 88 is normally held in a closed position by means of a compression spring and is automatically opened by the energization of a solenoid 88. When the control valve 28 is shifted to cause a forward feeding movement of the grinding wheel ll, fluid under pressure is passed through the pipe 22 and also through a pipe 81 to convey fluid to the solenoid valve 88. When the starter switch II is closed to initiate a forward movement of the grinding wheel, the energizing of the relay switch 48 serves not only to energize the solenoid 81 but also to energize the solenoid 88 and thereby to open the solenoid valve 88. In this position of the valve 85, fluid under pressure passing through the pipe 81 passes through the valve 85 and through a pipe 88 to a cylinder chamber 88 formed at the lower end of a cylinder 88. The cylinder 88 contains a slid-.

ably mounted piston 8| which is connected to the lower end of a piston rod 82. The cylinder 88 and the piston rod 82 are arranged in axial alignment with the actuating plunger 88 of the limit switch 88 so that when the piston rod 82 moves upwardly. it will engage and actuate the plunger 84 and thereby close the normally open limit switch 88. I

During the upward movement of the piston 8|, fluid within a cylinder chamber 88 may pass down through a pipe 88, through a throttle valve 88,

through a pipe 88 which connects with pipe l8.

When the control valve 28 is in a forward feeding position, the pipe i8 is connected to exhaust fluid through pipe 88. It will be readily apparent from the foregoing disclosure that the rate of movement of the piston 8| and the piston rod 82 may be readily controlled and govcrnedby the setting of the throttle valve 88. This valve 88 is preferably adjusted so that the piston rod 82 will move upwardly and engage the plunger 88 and close the limit switch 88 when the grinding wheel H is about to engage the peripheral body portion of the work piece I2. It will be readily apparent that regardless of the initial diameter or size of the work piece I2, the feeler roller I8 will position the limit switch 88 sothat the change from shoulder to a body feed will occur when the wheel reaches the same identical position relative to the work periphery.

In order to return the piston 8| to its downward or initial position, the pipe 88 is connected through a check valve 81 with the pipe 84 so that when fluid under pressure is admitted through the pipe 88, it may bypass the throttle valve 88 and pass directly through the pipe 94 rapidly to fill the cylinder chamber 88 and return the piston 8| to its rearward or inoperative position.

It is desirable to deenergize the solenoid 88 when the wheel slide l8 reaches or approaches its rearward position. This is preferably accomplished by providing a normally closed limit switch 88. This switch is preferably located on or fixedly mounted relative to the base 8 of the machine. The rearwardly extending portion 88 of the piston rod I8 is provided with an adjustably positioned block having a cam surface I88 which is arranged to engage an actuating roller 89 of the limit switch 88 when the wheel slide I8 app oaches its rearward position to open theclockwise direction to close the starter switch 8|.

The closing of the switch 4| serves to energize the relay switch 45 which in turn serves to energize the solenoid 81 to shift control valve 28 so as to cause a forward feeding movement of the grinding wheel II and at the same time to energize the solenoid 88 to open the solenoid valve 88 so that fluid under pressure passes to the cylinder chamber 8|. The grinding wheel II and its supporting slide I8 move rapidly to position the wheel adjacent to a shoulder portion on the work piece to be ground. The flanged member 88 is preferably adjusted so that the flanged portion work I2 at which time the piston rod 82 moving in an upward direction engages and moves the actuating plunger II to close the normally open limit switch II thereby energizing the solenoid Q! to close the solenoid valve ll thus cutting out the throttle valve ll so that a body grinding feed governed by the needle valve II and the throttle valve is automatically obtained as the wheel moves into engagement with the peripheral body portion of the work to be ground. It will be readily apparent from the foregoing disclosure that the change to a body feed occurs automatically as the wheel engages the work regardless of the initial diameter of the work piece to be round.

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 set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim: Y

1. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor. and a feeding mechanism for said slide to feed said slide rapidly toward and from'awork piece to be ground, means to slow down the rapid approaching feed to a predetermined grinding feed to grind a shoulder on a work piece, and means including a work engaging feeler engageable with the work piece to .be ground automatically to slow down the grinding feed to a slower predetermined grinding feed when the grinding wheel engages the peripheral portion of the work to be ground.

2. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, and a feeding mechanism for said slide including a fluid pressure piston and cylinder to feed said slide rapidly toward and from a work piece to be ground, means to slow down the rapid approaching feed to a predetermined grinding feed to grind a shoulder on a work piece, a work engaging feeler engageable with the work piece to be ground, and means including a control device movable with said feeler automatically to slow down the grinding feed to a slower predetermined grinding feed when the grinding wheel engages the peripheral portion of the work piece to be ground.

3. In a grinding machine having a rotatable grinding wheel, a transversely movable slide for said wheel, and a feeding mechanism therefor including a piston and cylinder to feed said slide rapidly toward and away from a work piece to be ground, means including a dash pot feed regulator to slow down the rapid approaching to a predetermined grinding feed. a work engaging feeler engageable with the periphery of the work piece to be ground, and means including a limit switch movable with said feeler automatically to slow down the grinding feed to a slower predetermined grinding feed when the grinding wheel engages the peripheral surface of the work to be ground irrespective of the initial diameter of the work piece to be ground.

4. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, and a wheel feeding mechanism including a hydraulic piston and cylinder to move said slide rapidly toward and from a work piece to be ground, 'a dash pot feed regulator which is arranged to reduce the rapid approaching movement to a predetermined shoulder grinding feed, a throttle valve to control the rate of exhaust from said regulator. a second throttle valve which is connected in parallel with the first throttle valve, said throttle valves serving to facilitate adjustment of said shoulder grinding feed, a solenoid valve which is arranged when closed to render the second throttle valve inoperative so that the first throttle valve controls exhaust from said regulator, and control means including a work engaging feeler to close said solenoid valve when the grinding wheel is about to engage the peripheral surface of the work piece-regardless of the initial size thereof automatically to reduce the shoulder grinding feed to a predetermined body feed.

5. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, and a feeding mechanism to feedsaid slide rapidly toward and from a work piece to be ground, means to slow down the rapid approaching feed to a predetermined shoulder feed, a movable work engaging feeler, a limit switch movable with said feeler, and means including a time delay mechanism for actuating said limit switch after a predetermined time interval automatically to slow down the shoulder grinding feed to a predetermined body feed when the grinding wheel engages the periphery of the work to be ground irrespective of the initial diameter of the work.

6. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, and a feeding mechanism for said slide to feed said slide rapidly toward and from a work piece to be ground, means to slow down the rapid approaching feed to a shoulder grinding feed, a work engageable feeler, a limit switch which is supported to move with said feeler, an adjustable time delay mechanism to actuate said limit switch, means actuated by and in timed relation with the infeeding movement of said wheel slide to set said time delay mechanism in motion, and means actuated by said limit switch automatically to slow down the shoulder grinding feed to a slower predetermined body feed when the grinding wh'eel engages the periphery of the work to be ground irrespective of the initial size of the work.

7. In a grinding machine having a rotatable grinding wheel. a transversely movable slide therefor, and a feeding mechanism for said slide to feed said slide toward and from a work piece to be ground, means to slow down the rapid approaching feed to a shoulder grinding feed, a pivotally mounted work engaging feeler normally engageable with the periphery of the work piece to be ground, a limit switch mounted to move with said feeler, a hydraulically actuated time delay mechanism including a piston and cylinder operatively connected to actuate said limit switch, means including a solenoid valve to admit fluid under pressure to said timing cylinder when a forward feed of the grinding wheel is initiated, a throttle valve to control the rate of movement of said time piston so as to facilitate actuation of said limit switch, and means including a solenoid valve actuated by said limit switch automatically to slow down the shoulder feed to a slower predetermined body feed when the grinding wheel engages the periphery of the work to be ground.

8. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, and a feeding mechanism iorsaid slide to feed said slide rapidly toward and from a work piece to be ground, means to slow down the rapid approaching ieed to a predetermined shoulder grinding feed, a pivotally mounted ieeler normally engageable with the periphery of the work piece to be ground, a limit switch mounted to move with said ieeler, a hydraulically operated time delay mechanism including a pistonand cylinder arranged to actuate said ieeler switch after a predetermined time interval, a solenoid valve to control the starting or said time delay mechanism, a limit switch actuated by and in timed relation with the im'eeding movement of said slide to actuate said solenoid valve and thereby to start said time delay mechanism, and means including a solenoid valve actuated by said i'eeler switch automatically to change the wheel slideieedingmovement to a predetermined body feed,

as the grinding wheel engages the peripheral portion oi! the work pieceto be ground irrespective of the initial diameter 01' the work piece.

I HERBERT A. SILVEN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS

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