US2205373A - Grinding machine - Google Patents

Description

June 18, 1940. J. DECKER! 2,205,373

GRINDING MACHINE Filed Nov. 7, 1938 3 heets-Sheet 1 I INVENTOR.

.j coe fife/rm ATTORNEY.

June 18, 1940. J DECKER GRINDING MACHINE Filed NOV. 7-, 1938 3 eet 2 INVENTOR. J4coa 'fifC/ff/P v ATTORNEY.

June 18, 1940. MECK'ER T 2,205,373

GRINDING MACHINE F i1 ed Nov. 7. 1958 5 -Sheet s INVENTOR. J4co5 fife/m? ATTORNEY.

Patented June 18, 1940 UNITED. STATES GRINDING MACHINE Jacob Decker, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated,

Cincinnati,

Ohio, a corporation of Ohio Application November 7, 1938, Serial No. 239,287

8 Claims.

This invention relates to grinding machines and more particularly to improvements incross feed mechanisms therefor.

One of the objects of this invention is to provide .an improved and simplified cross feed mechanism for a grinding machine,

Another object of this invention is a contrive a cross feed mechanism that may be selectively coupled for automatic operation in accordance with table traverse, or self-actuated during non-traverse of the table.

A further object of this invention is to provide means whereby a cross feed mechanism of the pick feed type may be utilized for manual operation, automatic operating during traverse grinding, or automatic operation during plunger cut grinding.

Other objects and advantages of the present invention should be readily apparent by reference to the followingspecification, considered in conjunction With the accompanying drawingsforming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of th invention.

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

Figure 1 is a cross sectional view through a grinding machine and shows a portion of the cross feed mechanism.

Figure 2 is an enlarged detail view of the pick feed wheel and motion transmitting connections associated therewith.

Figure 3 is a view in elevation showing the power operating mechanism for the pick feed pawl.

Figure 4 is a diagrammatic view of the control circuit for the pick feed pawl.

Referring to Figure 1 of the drawings the reference numeral It indicates a grinding machine table which is slidably mounted on guideways H and I2 for traversing movement relative to the supporting bed 13. This table carries the usual headstock l4 containing power operated means for rotating the work relative to a grinding wheel IS. The grinding wheel is rotatably mounted on a support i6 which is guided for movement on the bed iii in a direction toward and from the axis of rotation of the work.

In grinding machines of the character described .the operations performable thereon may traverse grinding the surface to be produced on the work is longer than the grinding wheel is wide,and the table is therefore reciprocated to move thework back and forth in front of the grinding wheel. This reciprocation is effected by power means which in the present instance may consist of a hydraulic motor of either the piston and cylinder type, or of the rotary type. The former has been utilized herein 'and consists of the cylinder l1 and piston l8, the cylinder being fixed with the table and the piston being connected to the bed by the piston rod l9.

In order to reduce the work to size, the grinding wheel is moved toward the work a definite amount after each stroke of the table by a cross feed mechanism, and this is accomplished automatically by utilizing the'moving table as a timing and actuating means.

In the plunge out grinding the surface to be produced is equal to or less than the width of the grinding wheel whereby it becomes unnecessary to traverse the table. The grinding wheel,

} grinding operations.

The mechanism for feeding the grinding wheel support it includes a rotatable shaft which is connected through a worm and worm wheel 2! to a vertical shaft 22 having a pinion 23 which meshes with a rack bar 2 8 secured'to the underside of the support 16. The rotatable shaft may be selectively connected in two different ratios to a shaft 25 as shown in Figures 1 and 2. A gear couple comprising gears 26 and 21 is fixed to the shaft 25. A gear 28, supported for free rotation on the shaft 20, is in constant mesh with the gear 26. A second gear 29 is splined on the' shaft 20 for movement into mesh with the gear 21. The gear29 has clutch teeth on one end for interengagement with clutch teeth on the adjacent face of gear 28 whereby when the gear 29 .is shifted to the left, it is withdrawn from en- I :gagement with the gear 21 and operatively connects the gear 28 to the shaft 20. When the gear 29 is shifted to the right the clutch teeth are disconnected whereby the gear 28 is rendered 7 ineilective during rotation of the gear 25. by the gear 21.

The shaft 25 forms part of a pick feed mechanism and has an enlarged portion 3| which is supported for rotation in a fixed bushing 32. An internal gear 33 is secured to shaft 3| for engagement with an eccentric gear 34. A'second gear 35, integral with the gear 34, intermeshes with an internal gear 35 forming part of the pick feed wheel 31. The pickfeed wheel is supported for rotation on ashaft 35 which has an extension 39 bearinged in the center of the shaft 3|. The shaft 35 has an eccentric journal 45 which supports the gears 34 and 35 for rotation about an axis eccentric to the axis of the shaft 35. A hand wheel 4| is keyed at 42-to shaft 35 whereby upon rotation of the hand wheel the eccentric 45 is caused to move around the axis of the shaft 35 carrying the gears 34 and 35 with it.

If the pick feed wheel is held stationary, this will cause rotation of the gear 35, and thereby transmit motion through the gear 34 to the internal gear 33, which, being integrally con nected to shaft 25, will cause rotationof the gears 25 and 21. Dependent upon the position of the shiftable gear 25, one of the gears 25 or 2Lwill cause rotation of the shaft 25. When the hand wheel'is rotated in this manner it will effect a fine adjustment of the grinding wheel support.

The hand wheel 4| .can'ies a spring pressed plunger 43 which is adapted to be inserted in a series of holes 44 formed in the pick feed wheel 31 whereby the hand wheel and the pick feed wheel may rotate as a unit and thereby effect direct rotation of the gears 25 and 21 and thereby a faster rotation of the shaft 25 per revolution of the hand wheel. By means of this mechanism the grinding wheel support may be manually adjusted at will and at different rates per revolution of the hand wheel.

The shiftable gear 29 is provided with an integral flange 45 which'is engaged by a shifter fork 45 carried by a shifter rod 41. The rod is normally held in a position by spring 45 to hold the gear 25 in clutched relation with the gear 25. The shifter rod is moved by a spiral gear 45 supported for rotation on the end of shaft 55, the spiral gear intermeshing with spiral teeth out in the periphery of the shifter 41. A handle 5| secured to the projection end of the shaft 55 serves as means for rotating the same.

For automatic power operation of the pick feed wheel there is provided a pickfeed lever 52 which is supported for free rotation on the hub of the bushing 32 and provided with a pick feed pawl 53 for engagement with. the teeth 54 formed on the periphery of the pick feed wheel 35. The hub 55 of the lever, Figure 3, has a series of gear teeth 55 formed.on the periphery thereof for interengagement with gear teeth 51 formed on the end of a pivoted lever 55. The lever 55 is fixed with a shaft 55 which in turn has a fixed lever 55 carrying a follower roller 5|. The follower roller is positioned to engage a cam surface 52 formed on the periphery of a hydraulically actuated piston 53. The piston is reciprocably mounted in a cylinder 54. The cam 52 is formed with a peak 55 midway of its length whereby as the piston moves toward its center position from either side it will cause clockwise rotation of the lever 55 and counterclockwise r0 tation of the pick feed lever 52. A spring pressed plunger'55 acts on the lever 55 to maintain the e upper end of this lever is roller in contact with the cam and to urge the lever 52 to its return position.

In order to vary the length of the pick feed, an adjustable return stop is provided, comprising a stop screw 51 which is threaded in a fixed lug 55. A look nut 55 threaded on the screw 51 serves to secure the parts. in a fixed position. It will be apparent that by adjusting the stop screw 51 to the left, as viewed in the drawings, the lever 52 will be limited in its return movement, and furthermore, the roller 5| will be limited in its return movement toward the cam 52 and this provides a variable amount of lost motion be-' tween the piston 53 and the roller 5| before the same is actuated. In this way, the piston may be caused to eifect variable amounts of movement to the pick feed lever.

A ratchet dog 15 has been provided for automatically stopping the pick feed action and this dog is carried by and movable with the pick feed wheel 35.

The dog has a head portion II in which is formed a T-slot 12 which embraces the T-shaped rim of the pick .feed wheel 35. Axially movable pin 13 serves to lock the ratchet dog in any adjusted position around the periphery of the wheel 35.

An independently operating hydraulic circuit has been provided for reciprocating the piston 53 to eflect automatic infeed of the grinding wheel for plunge cut grinding purposes, when the table is stationary. This circuit includes means for imparting to the piston hydraulic pulsations or impulses alternately in opposite directions so that the piston 53 operates as a pulsator having a relatively high speed oscillation for producing the successive incremental pick feed actions for relative infeed of work'and grinding wheel. The opposite ends of the cylinder 54 are connected by hydraulic channels I4 and 15, Figure 4, to

intake 54, through which fluid iswithdrawn from reservoir 55 has a delivery channel 55 which is connected to port 51 of valve 52. When the plunger 55 of this valveis rotated in a clockwise direction from the position shown in Figure 4, the pressure port 51 is connected to port 5|.- whereby the port 15 of the reversing valve is supplied with pressure. The reversing valve has a plunger 55 on which is formed a central spool 55 and end spools 5| and 52, resulting in intermediate annular grooves 53 and 54. When the plunger 55 is in the position shown, the pressure port 15 is connected to port 15 whereby fluid will flow to the left end of cylinder 54 to cause the same to move toward the right and the fluid in the right hand end of the cylinder will return to reservoir through port 'i'l, annular groove 54 and port 55 tochannel 55. This channel terminates in port 51 of the stop valve which will be connected through port 55 to return channel 55.

The reversing valveplunger is automatically power shifted at predetermined intervals under control of a pilot valve I55 and a timing mechanism which governs the shifting of the pilot valve plunger Ill. The pilot valve has a pair of ports I52 and 53 which are alternately con-'.

opposite ends of the reversing valve. Thin, when 75 II2, whereby the pressure fluid acts on the end the port I06 is connected to the port I02 the reversing valve plunger is shifted to the left. When the port I03 is connected to pressure, the port I02 is connected by the annular groove I04 to the exhaust line I09 and when the port I02 is connected to pressure the port I03 is connected to the exhaust line 96.

The pilot valve plunger is, in turn, hydraulically shifted in accordance with the pressure condition in channels 14 and 15. For instance, with the stop valve 38 in a running position, the channel 14 would be under pressure and the channel 15 connected to exhaust. The pressure in channel 14 is now utilized to eflect shifting of the pilot valveand this is effected by providing a shuttle valve IIO which has spring pressed plunger III normally held in a position to disconnect the port II2 from the port H3 which is connected by a branch line II4 to the channel 14. The pressure fluid entering channel I I4 and port I I3 urges the plunger III downward against the resistance of spring II6, uncovering the port of plunger IOI to shift the same toward the right. since the right hand end of the pilot valve I is filled with fluid, due to previous operation, this fluid must be exhausted in order that the plunger may move.

A second shuttlevalve IIG connected to the right hand end of the pilot valve also has a spring pressed plunger II1 which, in its normal position, connects port M3 to port H3. The port H9 is connected by channel I20 to port I2I of an adjustable delay valve I22. This valve has a plunger I23 in which is formed a series of V-shaped grooves I24 to restrict the flow from port I2I to an exhaust port I25. By adjusting the position of this valve by the threaded plunger I28, the-rate of escape of fluid from the right hand end of the pilot valve can be addusted to vary the time which it will take the pilot valve plunger to move toward the right a suiflcient distance to interconnect the pressure port I06 with port I02. It should now be evident that after the pick feed mechanism has been actuated, the fluid pressure in channel 14 continues to act to shift the pilot valve plunger, but this movement is retarded by the delay valve so that a predetermined time interval exists before the reversing valve is again shifted to effect the next actuation of the pick feed mechanism. 7

The samething istrue when the channel is put under pressure because the channel 15.

'pick feed piston may be controlled from the table during traverse grinding. The channels 14 and 15 have branch connections I3I and I32 to ports I33 and I34 ofa selector valve I35, having rotatable valve portions I35I and I352. The selector valve serves to connect ports I33 and I34 to ports I36 and I31 respectively which have branch lines I30 and I33 connected to motor supply lines I40 and I for the table actuating motor. The channels I40 and I are adapted to bealter- 'nately put under pressure and'exhaust by suitably known means, to cause reciprocation of the piston I8 in the cylinder I1. The selector valve has additional valve portions I42 and I43 where'- by when the valve plunger is positioned to connect the ports I33 and I34 to ports I36 and I31, the motor channels I40 and I are connected to lines- I44 and I45 leading ,to the table motor. The stop valve plunger 08- and the selector valve plunger are integral whereby in one position the self-actuating circuit is connected to pressure, the ports I33 and I34 are closed and the table cylinder I1 is disconnected from the motor supply lines I40 and I. Y source of pressure is disconnected from the selfactuating circuit, and the pick feed cylinder 64 and the cylinder I1 are connected in parallel to the motor supply lines I40 and III whereby every time the pressure is reversed in these channels the pick feed piston is shifted.

' There has thus been provided an improved control circuit for the infeed mechanism 01 a grinding machine whereby automatic pick feed may be obtained regardless of the method of grinding. v

I claim:

i. In a grinding machine of the type embodying a. relatively traversable work support, and wheel head and means including a hydraulic piston and cylinder mechanism for efiecting said traverse, means for controlling relative movement of said support and wheel head in a feeding direction, including a source of hydraulic medium under pressure, aflrst hydraulic conduit system couplable with the traversing piston and cylinder, a feed mechanism, a second hydraulic conduit system coupled with the feed mechanism, a third hydraulic conduit system including an independent, reversing system for producing alternate pulsations or impulses in opposite directions in the system, and selector means operable to couple the feed control mechanism in parallel with the first hydraulic system or in series with the second hydraulic system whereby the feed mechanism may be selectively operated by reversals of the traversing system or by intermittent alternate movements in accordance with the impulses of the series coupled system.

2. In a grinding machine of the type embodying a relatively traversable work support and wheel head and means including a hydraulic piston and cylinder mechanism for effecting said traverse, means for controlling relative movement of said support and wheel head in a feeding direction, including a source of hydraulic medium under pressure, a first hydraulic conduit system couplable' with the traversing piston and cylinder, 9. feed mechanism, a second hydraulic conduit system coupled with the feed mechanism, a third hydraulic conduit system including an independent,reversing system for producing alternate pulsations or impulses in opposite directions in the system, selector means operable to couple the feed control mechanism in parallel with the first hydraulic system or in series with the second hydraulic system whereby the feed mechanism may be selectively operated by reversals of the traversing system or by intermittent alternate movements in accordance with the impulses of the series coupled system, and means for variablydetermining the frequency of said impulses and to determine the coupling of thesource of pressure with the pulsatable member, a pilot valve shiftable to eilect opposite positionings of said reversing valve, means for controlling the positioning of the pilot valve including a branch hydraulic circuit coupled in parallel with the pulsator and a pressure actuated valve shiftable by pressure in said branch circuit for operatively coupling the circuit with the pilot valve to initiate opposite positioning of the reverser, and means for variably determining the rate of movement of the pilot valve and thus the time interval of the pulsations.

4. An infeed control mechanism for a machine tool including a pulsatable member and a hydraulic circuit for determining the pulsations thereof including a source of hydraulic medium under pressure, a reversing valve variably positionable to determine the coupling of the source of pressure with the pulsatable member, a pilot valve shiftable to effect opposite positionings of said reversing valve, means for controlling the positioning of the pilot valve including a branch hydraulic circuit coupled in parallel with the pulsator and a pressure actuated valve shiftable by pressure in said branch circuit for operatively coupling the circuit with the pilot valve to initiate opposite positioning of the reverser, means for variably. determining the rate of movement of the pilot valve and thus the time interval of the pulsations, and additional valve means for determining the operative coupling of the pilot valve with said rate determinator.

5. In a machine tool comprising a pair of support members mounted for relative feeding movement and means for producing-said movement including a pulsator and a hydraulic mechanism for determining the pulsations thereof including a source of hydraulic medium under pressure, a reversing valve for effecting alternate directional couplings of the medium with the pulsator, a pilot valve for determining the position of the reversing valve coupled in parallel with the pulsator whereby movement of thereversing valve will react on the pilot valve to effeet a reversal thereof, said pilot valve including terminal piston portions, an adjustable delay device, conduits coupling the piston portions of the pilot valve in parallel with the delay device, and independent valve members interposed in the conduits connecting the pulsator and pilot valve pistons and actuable by existence of pressure in the related conduit for disconnecting the associated pilot valve piston as respects the delay device, substantially as and for the purpose described.

6. In a machine tool comprising a pair of support members mounted for relative feeding movement and means for producing said movement including a pulsator and a hydraulic mechanism for determining the pulsations thereof including a source of hydraulic medium under pressure, a reversing valve for effecting alternate directional couplings of the medium with the pulsator, a pilot valve for determining the position of the reversing valve coupled in parallel with the pulsator whereby movement of the reversing valve will react on the pilot valve to effeet a reversal thereof, said pilot valve including terminal piston portions, an adjustable delay device, conduits coupling the piston portions of the pilot valve in parallel with the delay device, valve members disposed adjacent the termini of the pilot valve, and means resiliently urging said valve members in position to couple the pilot valve pistons with the delay device, said valves having piston portions individually actuable by pressure in the coupled end of the pulsator whereby said valves will be individually shifted by said existing. pressure to disconnect the delay device and admit pressure by way of the valve to react on the associated pilot valve piston portion.

'7. An infeed control mechanism of the character for effecting substantially continuous relative infeed of work and grinding wheel, including a pulsatable piston, a pick feed mechanism actuable by the pulsations thereof, means for effecting pulsations of said piston including a pressure source, independent pilot and reversing valves, branch pressure conduits coupled with the respective valves, potential pressure conduits interconnecting the pilot and reverser valves, additional conduits interconnecting the reverser valve and the pulsator, a cylinder enclosing the pilot valve, a pair of discharge lines extending from the termini of the pilot valve cylinder to receive exhaust fluid therefrom, individual control valves for the pilot cylinder exhaust conduits, conduits individually coupling said valves at opposite ends of the pilot cylinder in parallel with the opposite ends of the pulsator, said valves having piston portions actuable by pressure in said parallel couplings for shifting the valves whereby pressure in either end of the pulsator will shift the associate valve to close the reservoir connection at one end of the pilot valve cylinder and admit said coupled pressure into the cylinder for shifting of the pilot valve.

8. Aninfeed control mechanism of the character for effecting substantially continuous reladditional conduits interconnecting the reverser valve and the pulsator, a cylinder enclosing the pilot valve, a pair of discharge'lines extending from'the termini of the pilot valve cylinder to receive exhaust fluid therefrom, individual control valves for the pilot cylinder exhaust conduits, conduits individually coupling said ,valves at opposite ends of the pilot cylinder in parallel with the opposite ends-of the pulsator, said valves having piston portions actuable by pressure in said parallel couplings for shifting the valves whereby pressure in either end of the pulsator willshift the associate valve to close the reservoir connection at one end of the pilot valve cylinder and admit said coupled pressure into the cylinder for shifting of the pilot valve, and an adjustable delay means in the exhaust conduits for the pilot valve, whereby said means will variably determine the rate of movement of the, pilot valve and determine the time internal between positive actuations of the reversevalve.

JACOB DECKER.

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