US2178850A - Spindle oscillator - Google Patents

Description

NOV. 7, 1939. L 2,178,850

' SPINDLE OSCILLATOR Filed Dec. 6, 1937 2 Sheets-Sheet 1 JL/b: 7 Z

INVENTOR. A L5 5/? TH DAL L BY I ATTORNEY.

Patented Nov. 7, 1939 ATENT, OFFIQE SPINDLE OSCILLATOR Albert H. Dall, Silverton, Ohio, assignor to Cin cinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application December 6, 1937, Serial No. 178,286

9 Claims. (Cl. 121-157) This invention relates to grinding machines and more particularly to improve means for effecting oscillation of the grinding wheel spindle of such machines for the purpose of eliminating .5 grinding lines from the work.

One of the objects of this invention is to provide a mechanism for the purpose described which will have a smooth reversal, thereby eliminating any shock or undesirable vibration which will impair the finish on the work.

Another object of this invention is to provide a mechanism of the character described which is positive in action and therefore will not stall at the reversing points.

A further object of this invention is to provide improved control mechanisms for starting and stopping the device, and for varying the length and time of a stroke, said last named mechanism being adjustable during operation of the device.

Other objects and advantages'of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings illustrative of one embodiment thereof, but it will be understood that any modifications may be made in the specific structural details within the scope of the appended claims without departing from or exceeding the spirit of the invention.

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

Figure l is a section through the spindle of a grinding machine showing the application of the reciprocating mechanism thereto,

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a plan view of the top of the mechanism shown in Figure 2.

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

Figure 5 is a diagrammatic view of the hydraulic control circuit.

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

Referring to Figure l of the drawings, the reference numeral ll] indicates the spindle of, a grinding machine, said spindle being supported for rotation in bearings H and i2 carriedby the main support 53 of the machine. It will be noted that the bearings are straight whereby the spindle may be axially reciprocated relative thereto.

A conventional driving pulley I4 is secured to one end of the spindle for efiecting power rotation thereof, and a grinding wheel I5 is secured to the other end by suitable conventional clamping means.

This invention deals with a mechanism for effecting a limited amount of reciprocation oi the spindle during rotation of the'grinding wheel, for the purpose of removing grinding marks or lines from the work to improve the finish thereof. To 5 this end the spindle is provided with an annular rib H; which is antifrictionally embraced by a surrounding sleeve ll, the sleeve in turn being pivotally connected at diametrically opposite points ll, as shown in Figure 2, to an operating 10 lever I 8. This lever has a ball shaped end I9 by which it is supported for pivotal movement between the cup. shaped ends of locating members 20. This ball and socket connection serves as a pivot point for oscillation of the lever. The 15 sleeve thus serves as a motion transmitting connection between the oscillating lever and the rotating spindle for efiecting oscillation of the spindle.

The other end of the lever has a ball and sock- 20 et connection 2| with the central portion of a piston 22 which is reciprocably mounted in-a cylinder 23. It will now be obvious that by introducing fluid under pressure into one end of cylinder 23 and connecting the other end to ex- 25 haust, that the lever l8 may be power moved to thereby cause reciprocation of the grinding wheel.

A control mechanism has been provided for governing the admittance and exhaust of fluid to cylinder 23 in such a manner that reversal 3 thereof may be efiected in a very smooth and efficient manner so that no undesirable shock or vibration will be created which will impair the finish which it is desired to produce on the work. This reversal is efiected by a member moving at 35 a rate independent of the rate of the other moving parts, whereby a definite period of time may be provided for reducing the pressure in one end of cylinder 23 and increasing the pressure in the other end to provide, first, an equalized pressure 0 in both ends to stop the movement of the piston, and then a further and continued inverse pressure change to ultimately effect movement in a new direction. The movement of the reversing member is initiated by a pilot valve, and there- 45 after it is independent of the pilot valve in that the movement will continue regardless of whether the pilot valve should stop moving or not.

Referring to Figure 5, the reversing valve consists of an axially movable sleeve 24 which has a 50 central annular groove 25 which is always in communication with an exhaust line 26. This sleeve also has a pair of annular grooves 26' and 27 which are always in communication with pressure ports 28 and 29 respectively. These ports 55 are connected by a channel to a suitable source of pressure, such as a pump 3|, which has an intake 32 through which fluid is withdrawn from a suitably located reservoir 33. For protective purposes an overload relief valve 34 may be connected to the channel 30. The rate of movement or reciprocation of the grinding wheel may be controlled by providing a throttle valve 35 in the channel 3i: to thereby vary the rate of fluid delivered per unit of time to the cylinder.

The opposite ends of the cylinder 23 are connected by channels 38 and 31 to ports 39 and 38 formed in the valve housing 40 and located between the exhaust groove 25 and the pressure ports 23 and 29. It will now be apparent that when the sleeve is at one end of its stroke, that the pressure groove 26 is connected to the port 38, and that the port 39 is connected to the exhaust groove 25 whereby the piston 22 will move toward the left, and when the sleeve 24 is shifted to the other end of its stroke that the port 39 will be connected to the pressure groove 21 and port 38 will be connected to exhaust groove 25 whereby piston 22 will move toward the right as viewed in Figure 5.

The sleeve 24 is constrained to move at a relatively moderate rate as compared to the high speed shifting effected by load and fire mechanisms usually employed in machine tools for effecting reversal of moving parts. Load and fire mechanisms depend upon the controlled part for their actuation, while in the present instance, once the movement is started, it will continue regardless of whether the controlled part should stop or not. The result is that it is practically impossible for the mechanism to stall during operation.

The above result is obtained by providing'a pilot valve control mechanism for the reversing valve comprising a plunger 4|, which is supported for reciprocation in opposite ends of the housing 40, for controlling the time of starting of the shifting movement of the reversing valve sleeve. This plunger has a central spool 42, and end spools 43 and 44, the end spools being smaller in diameter than the central spool thereby providing difierential areas between opposing faces of the spools. The spool 42 moves relative to the exhaust port 25 for the purpose of closing the same, and the spools 43 and 44 move relative to pressure ports 45 and. 46 respectively for the purpose of alternately opening the same to cause admission of pressure to the annular grooves 41 and 48 formed in the plunger 4|.

The plunger 4| is always at the opposite end of its stroke to what the sleeve 24 is, at the beginning of a cycle. In other words, if the plunger 4| is all the way to the left, the sleeve 24 is all the way to the right. In Figure 5, the plunger 4| is shown in a central position or half way through a given stroke and it will be noted that the piston 22 is also shown as having moved half way through its stroke.

Since the sleeve 24 is in its right hand position, the plunger 4| must have started from its left hand extreme position. In that position, the annular groove 41 communicates with port 45, whereby pressure fluid acts on the left end of the sleeve 24, to shift the same into its right hand position, and on the differential areas of the spools 42 and 43, creating a resultant force on the plunger 4| in 'a right hand direction. This force urges the plunger into contact with the end of a lever 52, which is pivotally mounted ona' pin 53 carried by an adjustable supporting block 54. The other end of the lever engages a plunger 5|, shown in Figure 1, which in turn abuts the side of the lever l8. It will be remembered that the lever I8 is moved by the piston 22, and since the piston 22 is traveling toward the left, it permits clockwise rotation of the lever 52 under the urge of the resultant of the hydraulic pressure acting on the opposing ends of the differential spools 43 and 42.

A second lever 55 is pivotally mounted at the opposite end of plunger 4| on a pin 56 carried The lower end of by an adjustable block 51. this lever engages a plunger which in turn abuts the opposite side of lever l8. As the lever |8 moves toward the left under the urge of piston 22, it causes clockwise rotation of the lever 55. It is through the two levers 52 and 55, that motion is transmitted from the piston 22 to the plunger 4|. During the first part of the stroke of the plunger 4| it is hydraulically urged against one of these levers to follow the movement of the piston 22. After it reaches a position where the spool 43 closes the pressure port 45 or, when moving in the opposite direction, when the spool 44 closes the pressure port 46, the value of the differential hydraulic urge decreases to a point where the plunger will no longer follow the lever. Thereafter it must be positively moved by the other lever.

As the plunger 4| continues its movement toward the right from the position shown in Figure 5, the spool 42 closes the port 56 and thereby seals the annular groove 48 from the exhaust line 26 whereby a closed chamber is formed. Upon further movement, the pressure port 45 is uncovered by the spool 44 and the port 56 is connected to the annular groove 41. The result of this is that the pressure rises in the groove 48 and falls in the groove 41 and a suificient resultant is built up to cause movement of the sleeve 24 toward the left. It will be noted that movement of the sleeve 24 to the left will effect further opening of the exhaust port 56 thereby causing a further drop in the pressure in annular groove 41 so that a greater pressure differential is created between the ends of the sleeve which will accelerate the movement. In other words, the further the sleeve moves, the more the exhaust port is opened and even if the plunger 4| should stop its movement. As the sleeve moves toward the left, it closes the motor ports 38 and 39 whereby the pressure drops in the right hand end of cylinder 23 and rises in the left hand end. This causes deceleration of the piston 22 so that a smooth reversal may be effected without shock. It will be noted that this is accomplished during that part of the movement of sleeve 24 which is the slower. As the sleeve continues its movement at a more rapid rate, it connects motor port 39 to the pressure groove 21 and the motor port 38 to the exhaust groove 25. This will result in a more rapid rate of change of pressure in the opposite ends of the cylinder 23. It will thus be noted that the inverse change in pressure in opposite ends of cylinder 23 is effected at a constantly increasing rate of change.

Means have been provided for changing the stroke of the piston'22 and thereby the amount of the' lateral movement of the-wheel I5. This is accomplished by varying the amount of lost motion between the levers 52, and the plunger 4|. As previously mentioned, the lever 52 is pivotally mounted on'an adjustable block 54 and this block is guided by a plunger 58 which is slidably mounted in a bore 59 formed in the casting 6B. As shown in Figures 4 andfi, the plunger 58 has an annular groovetl formed therein for receiving an eccentric pin 62 formed integral with the rotatable shaft 63. This shaft projects through the top of the casting and is provided with an operating handle 54 which has a spring pressed plunger 65 in the end thereof. As shown in Figure 3, the. lever 64 moves relative to an indicator plate 65 in which is formed a series of small holes 57 for receiving the end of the plunger 65. To vary the stroke, the operator lifts on the plunger 65 and rotates the lever 65 and then releases the plunger. The result of this is that the eccentric pin 62 shifts the plunger 58 and thereby the fulcrum of lever 52.

It will be noted from Figure 1 that if the pivot pin 53 for the lever 52 is moved toward the right, that the lever l8 will move througha greater arc before it picks up the lever 52 and rotates it. For stopping the device the lever 55 is also mounted on an adjustable fulcrum as previously mentioned and as shown in Figure 6, the block is provided with an integral guiding plunger 68 which slides in a bore 69 provided in the casting 60.

Plunger 68 is provided with an annular groove TB into which fits an eccentric pin 1! integral with the end of. a rotatable shaft 12. This shaft projects through the top of the casting 60 and is provided with an operating handle 13. As shown in Figure 3, the handle 13 moves relative to an indicator plate 14 and has two positions, one of which is indicated at off and the other at on. When the lever is moved to the off position, the fulcrum 56 for the lever 55 is shifted a sufficient distance to the left that the lever l8 will not shift the plunger 4! a sufficient distance to open the pressure port 46. Whereupon the piston 22 will stop when it hits the end of cylinder 23 and be held against that end of the cylinder by hydraulic pressure. It should also be noted that this means that the wheel will always be stopped in the same position laterally.-

There has thus beenprovided an improved mechanism for the purposes described comprising a telescoping pilot and reversing valve with motion transmitting connections from the actuated part to the pilot valve, together with means for varying the amount of lost motion in those connections for varying the length of the stroke,

'and additional means for rendering one of the motion transmitting connections ineifective for stopping purposes.

I claim:

1. A hydraulic oscillator for the spindle of a grinding machine including a lever connected to said spindle, a hydraulic piston operatively connected to said lever, a source of fluid pressure, and valve means for controlling the application of fluid pressure to opposite ends of said piston including a pilot valve plunger, a sleeve surrounding said plunger, means in the sleeve for connecting said source of fluid pressure to opposite ends of said cylinder, multiplying linkage intervening the plunger and lever for imparting amplified movement to said pilot valve plunger by said lever, a fluid outlet and means in said pilot valve plunger during movement thereof for connecting pressure to one end of said sleeve and connecting the other end of said sleeve to said outlet for causing sleeve movement in a direction opposite to said plunger, said outlet connection being through said sleeve whereby movement of the sleeve will movement.

2; In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for effecting its reciprocation, a hydraulicpressure source including a hydraulic medium, a conduit for the medium, .a second conduitproviding a discharge outlet, a reversing valve for connecting said conduits to create pressure differentials on said piston causing opposite movements thereof, a pilot valve, means connecting said conduits for creating a pressure diiferential on both of said valves, motion transmitting 3 connections whereby the pilot valve is caused to follow up the movement of said piston under the urge of said pressure differential, means responsive to movement of the pilot valve for inversely changing the pressure differential on both of said valves whereby the reversing valve will move in a direction to inversely change the pressure differential on said'piston, and means in the reversing valve for increasing the rate of change of the pressure differential on itself in a direction to increase its rate of movement and thereby increase the rate of change in the pressure differential on said piston to effect reversal of the latter.

3. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected for reciprocation of the spindle, a source of fluid pressure having a delivery conduit, a second conduit providing a discharge outlet, a reversing valve for connecting said conduits tocreate opposite pressure differentials on said piston and thereby movement in opposite directions, a pilot valve, means connecting said pressure to one end of bothof said valves thereby holding the reversing valve in one extreme position to cause a definite direction of movement of said piston, motion transmitting connections whereby the pilot valve is caused to follow up the movement of said piston under the urge of said pressure, means responsive to a partial movement of said pilot valve for disconnecting the pressure source from one end of both of said valves and impounding the fluid, means responsive to the final movement of said pilot valve for connecting said pressure source to the other end of said valve will start to move, means on the reversing valve for releasing the impounded fluid at a gradually increasing rate and thereby equalize accelerate its own valves whereby the reversing the pressure on said piston whereby the piston.

and pilot valve will stop moving but the reversing valve will continue its movement, continued movement of. the reversing valve increasing the pressure differential thereon whereby its own movement will be accelerated and thereby effect an accelerated change in the pressure differential on said piston to effect reversal thereof.

4. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for effecting reciprocation thereof, a source of fluid pressure including a delivery conduit, a second conduit providing a discharge outlet, a reversing .valve having a first position for connecting the means responsive valve to follow the movement of the piston, means responsive to movement of thepilot valve for closing said pressure connection and nullifying said hydraulic urge whereby the piston will positively cause movement of. the pilot valve, and to further movement of the pilot valve for connecting pressure to the other end of said valves to cause shifting of the reversing valve. p

5. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for effecting its reciprocation, a source of fluid pressure including a delivery conduit, a second conduit providing a discharge outlet, a reversing valve for connecting said conduits to create a pressure differential on said piston and thus cause movement thereof, a pilot valve, means connecting said conduits for creating a pressure differential on both of said valves, a first motion transmitting connection between the pilot valve and piston whereby the pilot valve is caused to follow the movement of the piston under the urge of the pressure thereon, means responsive to movement of the pilotvalve for equalizing the pressure on opposite ends of said valve whereby the pilot valve will stop, a second motion transmitting connection from the piston for positively continuing the movement of the pilot valve, means responsive to further movement of the pilot valve for creating an inverse pressure differential on said valves to effect movement of the reversing valve, means responsive to movement of the reversing valve for accelerating its own movement to increase the rate of pressure differential change on said piston to effect reversal thereof.

6. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for effecting reciprocation thereof, a source of fluid pressure including a delivery conduit, a second conduit providing a discharge outlet, a reversing valve for connecting said conduits to said piston in a manner to cause movement thereof, a pilot control valve for said reversing valve, levers interposed between each end of the pilot valve and actuable by said piston, hydraulic means for causing the pilot valve to follow the movement of the piston during one half of its stroke, said levers positively moving mainder of its stroke, and means for adjusting the amount of lost motion between said levers and pilot valve to vary the length of stroke of said piston.

7. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for effecting its reciprocation, a hydraulic pressure source including a delivery conduit, a second conduit, a reversing valve for determining the connections of said conduits to'said piston for effecting opposite movement thereof, apilot valve, fluid pressure means controlled by said pilot valve for causing shifting of said reversing valve, levers pivotally mounted between said pilot valve and piston, each lever having one end adjacent said pilot valve and the other end adjacent a portion the pilot valve the reactuable by said piston whereby the pilot valve and piston will move in opposite directions, fluid pressure means for causingthe pilot valve to follow the movement of the piston during the first half of its stroke, said lever connections causing positive movement of the plot valve through the remainder of its stroke, and means to render one of said levers ineffective whereby the piston will complete its stroke without completing the shirting movement of said pilot valve.

8. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a piston operatively connected with said spindle for efiecting its reciprocation, a hydraulic pressure source including a delivery conduit, a second conduit, a reversing valve for determining the connections of said conduits to said piston for effecting opposite movement thereof, a pilot valve, fluid pressure means controlled by said pilot valve for causing shifting of said reversing valve, levers pivotally mounted between said pilot valve and piston, each lever having one end adjacent said pilot valve and the other end adjacent a portion actuable by said piston whereby the pilot valve and piston will move in opposite directions, fluid pressure means for causing the pilot valve to follow the movement of the piston during the first half of its stroke, said lever connections causing positive movement of the pilot valve through the remainder of its stroke, means to render one of said levers ineficective whereby the piston will complete its stroke without completing the shifting movement of said pilot valve, and means for adjusting the other of said levers to vary the amount of lost motion between the lever and pilot valve to thereby vary the stroke of said piston.

9. In a spindle reciprocating mechanism of the class described, the combination of a spindle, a

piston operatively connected with said spindle for effecting its reciprocation, a hydraulic pressure source including a delivery conduit, a second conduit, a reversing valve for determining the connections of said conduits to said piston for effecting opposite movement thereof, a pilot valve. fluid pressure means controlled by said pilot valve for causing "shifting of said reversing valve, levers pivotally mounted between said pilot valve and piston, each lever having one end adjacent said pilot valve and the other end adjacent a portion actuable by said piston whereby the pilot valve and piston will move in opposite directions, fluid pressure means for causing the pilot valve tofollow the movement of the piston during the first half of its stroke, said lever connections causing positive movement of the pilot valve through the remainder of its stroke, means to render one of said levers inefiective whereby the piston will complete its stroke without completing the shifting movement of said pilot valve, means foradjusting the other of said levers to vary the amount of lost motion between the lever and pilot valve to thereby vary the stroke of said piston, and a throttle valve located in said conduit for varying the rate'of operationof said piston.

ALBERT I-I. DALL.

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