US2171519A - Hydraulically operated surfacegrinding machine - Google Patents

Description

sept. 5, 192.9. A, G. BELDEN HAL HYDRAULICALLY OPERATED SURFACE-GRINDING MACHIN 20, 1938 5 Sheets-Sheet l Filed Aug.

FILEJERT BEELDEN CFIHL E. F'LYGHHE I @Mmeaxm' Sept. 5, 1939. 2,171,519

HYDRAULICALLYOPERATED SURFACE-'GRINDING MACHINE A. G. BELDEN ET A1.

Filed Aug. 20, 1938 3 Sheets-Sheet 2 3mm/vbo@ HLEERTEEELDEN CHRI. G FLYEHRE Sept.- 5, 1939- A. G. BELDEN ET AL.

HYDRAULICALLY OPERATED SURFACE-GRINDING MACHINE l 20, 1938 5 SheeS-Sheefl 3 Filed Aug.

EHRLGF'LYGHHE m" www Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE HYDRAULICALLY OPERATED SURFACE- GRINDING MACHINE Application August 20, 1938, Serial No. 225,978

9 Claims.

'Ihe invention relates to grinding machines, and more particularly to a surface grinding machine for grinding plane surfaces on a work piece.

One object of the invention is to provide a surface grinding machine with an electrically controlled transverse feeding movement for the grinding wheel. Another object of the invention is to provide a surface grinding machine with a hydraulically actuated electrically controlled transverse feeding. movement for the grinding wheel. A further object of the invention is to provide a hydraulically operated surface grinding machine with a tandem fluid pump one of which serves to feed the grinding wheel transversely during the period of reversal at the end of the table stroke and both of which serve to traverse the work table during the grinding stroke.

A further object of the invention is to provide a hydraulicallyoperated transverse grinding wheel feeding mechanism with an electrically controlled time delay mechanism to regulate the extent of transverse feed of the wheel. Another object of the invention is to provide a hydraulic counterbalance for the vertical slide to facilitate manual vertical adjustment of the grinding wheel. A further object of the invention is to provide a power operated vertical positioning mechanism for positioning the grinding wheel. Other objects will be in part obvious and 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 front elevation of the improved surface grinding machine;

Fig. 2 is a plan view of the improved surface grinding machine, on a slightly reduced scale;

Fig. r3 is a fragmentary detail .view of the power operated vertical feeding mechanism and the hydraulic counterblance; and

Fig. 4 is a diagrammatic illustration of the hydraulic system and the electrical wiring diagram for the automatic cross feed.

A surface grinding machine has been illustrated in the drawings having a base l which supports a longitudinally reciprocable work table I l on the usual V-way andv at way (not shown). A grinding wheel l5 is rotatably mounted on a transprise a manually operable feed wheel which 10 is mounted on the outer end of a shaft 2| which is journalled in bearings (not shown) in the base I0. The shaft 2| supports a worm 22 which. meshes with a worm gear 23. The worm gear 23 is provided with a central aperture which is threaded to mesh with a feed screw 24. The upper end of the feed screw 24 is connected to a lug 25 projecting from the vertically movable slide Il. A pair of'nuts 26 and 2l serve rigidly to secure the screw 24 to the lug 25. The worm gear 23 `is rotatably supported in housing 32, which is fixed relative to the base I0, so as rotatably to support the worm gear 23 and hold it against endwise movement so that when the gear 22 is rotated, the threaded aperture meshing with the feed screw 24 will produce an endwise vertical movement of the screw 24 together with the vertical slde Il, the wheel slide I6 and the grinding wheel I5.

Table reciprocating mechanism The table Il is arranged so that it may be reciprocated by a power operated mechanism to pass the work piece beneath the operative face of the grinding wheel'l5. In the preferred form, the reciprocating mechanism comprises a fluid pres' sure'system comprising a cylinder 35 which is xedly mounted by means of brackets 36 and 3l to the under side of the table Il. A pair of spaced pistons 33 and 39 are slidably mounted within the cylinder 35 and are connected lwith the hollow piston rods 4U and 4I, respectively, which are in turn fixed at their outer ends to brackets 42 and 43, respectively. The brackets 42 and 43 are fixedly mounted on opposite ends of the base I0.

The base l0 is preferably of a hollow box-like construction forming a uid reservoir 45, from which fluid is pumped by means of a iiuid pumpv through the pipe 49 enters through a port at the through a pipe 60 into a valve chamber 5|, and out through a pipe 62 into the reservoir 45.

Throttle valve In order to control the speed of movement of l the table during grinding, it is desirable to provide a suitable throttling device which in the preferred form comprises a throttle valve 65 preferably located within the exhaust pipe line 62 whereby the exhaust of fluid from the system is throttled to regulate the speed of movement of the table. This valve has been illustrated diagrammatically as a rotary type throttle valve (Fig. 4). A control lever 66 is provided for actuating the throttle valve to regulate the speed of movement of the table or to close the valve to stopthe table movement when desired.

A second fluid motor 10 preferably arranged in tandem with the fluid pump 46 and driven 'by the motor 41 is provided for actuating the transverse or cross feeding movement of the grinding Wheel |5 which occurs during the reversal movement of the work table Il. During the normal grinding stroke of the table I, the pressure from the pump 10 is utilized to supplement uid under pressure from the pump 46 so as to drive the work table at a higher rate of speed. The pump 10 forces fluid through a. pipe 1| and a pipe 12 to the grinding wheel cross feeding mechanism to be hereinafter described.

Fluid under pressure from the pipe 12 may also pass through a pipe 13 to a control valve 14 which is connected to operate in timed relation with the reverse valve 50. The valve 14 is vprei"- erably a piston type valve comprising a valve stem 15 having formed integrally therewith a plurality of valve pistons 16, 11 and 18. In the position of the valve shown in Fig. 4,'rluid under pressure from the pump 10 passing through the pipe 13 enters a valve chamber 19 located be'- tween the valve pistonsv 11 and 18 and is forced out through a pipe which is connected with the pipe 49 so that fluid under pressure from the pump 10 is forced through the pipe 49 to the table reversing valve 50 to aid the pump 46 in driving the table at a rapid rate. The valve'stem 15 is connected by a stud 8| with the lower end .of alever 82 which is actuated at reversal to cut olf the pipe'80 and thereby force all of the fluid from the pump 10 through pipe 12 for a denite interval during the shifting of the valve 50 into its reverse position. Y v

Transverse movement-grinding wheel 'I'he grinding wheel I5 and its supporting slide I6 are arranged so that they may be moved transversely by a manually operable mechanism including a manually operable hand wheel 85 mounted on the outer end of the shaft 86 which is operatively connected through. a gear mechanismto move a rack bar 81 endwisel..V The rack bar 81 is preferably fixed to the upper surface of the wheel slide I6 and serves to move the slide I6 and grinding Wheel I5 in either direction according to the rotation of the manually operable wheel 85. The manually operable feeding mechanism has not been illustrated in detail in the present application. This mechanism is substantially identical to that shown in the prior patent to Flygare et al. No. 2,022,542 dated November 26, 1935, towhich reference may be had for details of disclosure not found herein.

A power operated mechanism isv also provided for moving the grinding wheel slide I6 and the grinding wheel I 5 transversely at the ends of the table stroke so that on successive reciprocations of the work beneath the wheel I5, the wheel will grind a different overlapping path on the Work piece. In the preferred construction, a rotary fluid motor 90 is mounted on the vertical slide I1. This motor is a vane type motor having a single vane 9| mounted on a rotor shaft 92. The shaft 92 also carries a gear 93 meshing with a pinion 94 which in turn meshes with the rack bar 81 carried .by the wheel slide I6. A control or reversing valve 95 is provided to control the admission of fluid and the exhaust of fluid from the motor 90. The reversing valve 95 is of the piston type comprising a valve stem 96 having a plurality of valve pistons formed integrally therewith. Fluid under pressure passing through the pipe 12 passes through a pipe 91, a portion of which is preferably either flexible or telescopic, to a valve chamber 98 and passes out into a motor chamber 99 to cause the vane 9| to move in a counterclockwise direction (Fig. 4) which serves through the gear 93 and pinion 94 to move the rack bar 81 and wheel slide I6 toward the left (Fig. 4). During this movement fluid under pressure exhausts from a motor chamber |00 through a valve chamber I 0|y and a pipe |02 which exhausts into the reservoir 45.

A manually operable knob |95 is mounted on the outer end of the valve stem 9B and serves to facilitate manual shifting of the reversing valve 95.' A solenoid operated valve I 03 connected in the pipe line |02 and actuated by a solenoid |04 is normally closed and thereby serves to prevent movement'of the fluid within the wheel traverse system so as to hold the wheel slide I6 and grinding wheel I5 against transverse movement. The valve |03 is merely a shut-off valve and does not serve in any way to throttle the fluid when A throttle valve, preferably a needle type valve |06, is actuated by a manually operable knob |01 and serves to regulate the exhaust of-fluid from the system above described to control the normal rate of transverse feeding movement of the grinding wheel as it is indexed transversely.

In order to facilitate truing of the grinding wheel, itis desirable to provide a truing speed valve which is independent of the normal speed control valve whereby the wheel may be coritinuously traversed at a slow truing speed without disturbing the normal speed adjustment of the transverse movement of the grinding wheel. This is preferably accomplished by providing a second needle valve |10 which may be readily adjusted to throttle the exhaust of lluid from the motor 90 to produce the desired truing speed, 'and the valve is arranged so that it may be readily shifted to and from an operating position by means of a knob I so that during the normal operation of the machine, the valve IID is rendered inoperative and the valve |96 serves to control the eX- haust of fluid from the system.

Wheel slide' reversing mechanism in timed relation with the transverse movement of the wheel slide I0. A pair of adjustable dogs |20 and |2| are supported on a bar |22 carried by the wheel slide I6. The dogs |20 and |2| are arranged to engage a reversing lever |23 which is operatively connected to shift the valve stem 96 in an endwise direction to reverse the direction of movement of the wheel after it has traversed transversely through a predetermined distance to cover the width of the work piece being ground. A load and fire spring-pressed plunger (not shown) is contained within a casing |20 and serves normally to snap the reversing lever from one position to the other when 4actuated by the wheel slide dogs |20 and |2|.

This reversing mechanism has only been illustrated diagrammatically in Fig. 4. This reversing mechanism is identical with that shown in the prior patent to Flygare and Wood No. 2,022,542 dated November 26, 1935, to which reference may be had for details of disclosure not found herein;

Table reversing lever A reversing lever |30 is pivotally mounted on the front of the machine base and is operatively connected to shift the reversing valve 50 in timed relation with the longitudinal movement of the table to reverse the direction of movement of the same after it has traversed a predetermined distance. A pair of adjustable dogs i3! and |32 mounted on the front edge of the table serve to engage the reverse lever and to shift the lever and the reversing valve 50 to change the direction of flow of fluid to the cylinder 35. A load and fire mechanism (not shown) is provided to aid in shifting the valve 50 into its reverse position. This has not been illustratedinfdetail' in the present case since it is identical with that shown in the above mentioned prior patent tol Fiygare and Wood No. 2,022,542 dated November 26, 1935, to which reference may be had for details of disclosure not found herein.

Automatic grinding wheel cross feed The shut-off valve |03 above described is normally closed and is arranged to be opened by means of the solenoid |04. The valve |03 is maintained in a closed position during the longitudinal reciprocatory movement of the work table so as to hold the grinding wheel l5 against transverse movement. The valve |03 is opened during the period of reversal of the table to feed the wheel l5 transversely for grinding a new path on the work piece mounted on the table and closing of the solenoid valve |03 in timed relation with the reversing mechanism of the table A normally open limit switch |35 is mounted on the reversing lever |30 and is provided with an actuating roller |36 which is arranged in the path of the table dogs |30 and I3|. When either of the table dogs |3| or |32 engages the roller |36 of the limit switch |35, the limit switch is closed, after which continuous movement of the table through either the dog |3| or the dog |32 serves through the roller |36 to shift the lever |30 into its reverse position to reverse the position of the control valve 50 and thereby change the direction of ow of uid to the cylinder 35.so as to start the table traversing in the reverse direction. The switch |35 is connected by flexible BX conduits |3'l with an adjustable electrical time delay relay |38 and is connected by the wires |30 and |60 with the solenoid |00 on the r the operator.

It is desirable to control the opening valve |03. When the table dogs rock the roller |36 in either direction to close the limit switch |35, it closes a circuit to set the time delay relay V|38 in motion and also serves simultaneously to energize the solenoid |043 to open the valve |03, which allows fluid under pressure to exhaust from the feed motor 90. No fluid will flow into the feed motor 90, however, until the reversing mechanism has shifted a sufficient distance so that the valve piston il of the valve 'ifi cuts 01T the l pipe t0, cutting oif the output of the fluid pump l from the table cylinder l0 and sluiting to the pipe 97 to actuate the feed motor 90. The adjustable time delay relay |38 may be set to allow the solenoid |00 to be energized for a definite time interval, after which the solenoid |00 is deenergized and the valve |03 automatically closed to stop the transverse movement of the wheel I after a predetermined transverse feed of the grinding wheel has been accomplished.

Hydraulic counterbalcnce An adjustable by-pass valve |05 is provided in the pipe This valve determines the pressure applied to actuate the cross feed movement of the wheel. This valve -is preferably set so that sufficient fluid exhausts therethrough into a pipe |60 which is conveyed to a hydraulic counter.- balance mechanism comprising a cylinder |01 having a piston M8 slidably mounted therein. The piston M3 is connected to the lower end of the feed screw 2A. Fluid under pressure passing through the pipe |40 enters a cylinder chamber m9 below the piston |510 and serves normally to exert a pressure on the screw 2d in an upward direction. This uniform pressure is applied at all times to the feed screw so as to, in effect, counterbalance either the whole or part of the weight of the vertical slide and the parts carried thereby, so that the manually operable feed wheel 20 may be easily and readily rotated vertically to adjust the slide without undue exertion on the part of This vertical pressure exerted on the feed screw 20 also serves more accurately to control the positioning of the slide Il as well as the wheel slide i6 and grinding wheel l5 due to the fact that the pressure between the screw and the nut is always in the same direction regardless of Whether the vertical slide |'l is being moved upwardly or downwardly. The pressure within the cylinder chamber |03 may be governed by a by-pass valve |50 so that the required pressure may be obtained to produce the desired results.

Motor driven vertical movement of wheel It is desirable to provide a suitable power operated mechanism for raising and lowering the wheel in setting up the machine for grinding work pieces of varying predetermined sizes. This is preferably accomplished by providing a motor drive for the shaft 2|. An electric motor |60 is mounted within the base I0. A pulley |6| mounted on the motor shaft, which is preferably of a multiple V-grooved type, is connected by means of multiple V-belts |02 with a multiple grooved pulley .|03 mounted on the rear end of the shaft 2|. It will be readily apparent that when the motor |00 is rotated in either direction, a rotary motion will be transmitted to the shaft 2| to rotate it in either direction which,

- througliithe worm 22 and worm gear 23, willV produce a vertical movement of the feed screw 20, the vertical slide il, as well as the grinding wheel slide I6 and grinding wheel l5. A suitable control switch |65 is mounted on the front of the which when moved into the up position serves toA rotate the motor in one direction so as to cause an upward movement of the vertical slide "I1,

. wheel slide I6 and grinding wheel I5, and when moved to a down position serves to rotate the motor |66 in the reverse direction to cause a downward movement of the slide l1 and grinding Wheel I5. This motor driven mechanismvserves as a rapid positioning movement for the grinding wheel I5 in setting up the machine, the ne adjustment of the same being obtained by a manual manipulation of the feed wheel 26.

The operation of this improved surface grinding machine will be readily apparent from the foregoing disclosure. Assuming all of the parts have been previously adjusted, a work piece is placed on the table II and the lever 66 is shifted to permit exhaust of fluid from the table system. The motor 41 being in running condition serves to force fluid under pressure through the system to reciprocate the table II- through a stroke of a predetermined length as governed by the adjustablev table dogs |3| and |32. At the end of the stroke in either direction, when the dog |3I or the dog |32 nengages the roller |36 of the reversing lever |36, the roller |36 rst rocks relative to the lever v|36 to close the limit switch |35,

therebystarting the time delay relay |38 in operation and lsimultaneously energizing the solenoid |64 so` that the exhaust pipe line from the feed motor 96 is opened. Continued movement of either table dog |36 or |32 shifts the reversing valve 56 into a reverse. position and at the same time, through the lever 82, shifts the valve |14 to cut oil' the fluid motor 16 from the table cylinder 35 and transfers this uid under pressure from the pumpv 16 to index or feed the grinding wheel slide I6 and the grinding wheel I5 transversely during the time interval when the reverse valve is shifting to change the' direction of movement of the table I I. By manipulation of the time relay |38, the extent of cross feed of the grinding wheel may be varied as desired. During all of this movement of the machine, both reciprocationof the table during grinding and the transverse feeding movement of the wheel at reversal, a uniform pressure is maintained within the hydraulic counterbalance cylinder 35 and the lever 62 also shifts to move.

the valve stem 15 of the valve 14 toward the right to'cut off the pipe 13 so that valve piston 14 cuts off the pipes 13 and 66 so that all the fluid under pressure from the pump 16 is conveyed to the wheel traversing or feeding motor 66. When the valve 14 shifts to its extreme righthand position, a valve chamber |5| located between the valve pistons 16 and 11 again connects the pipe 13 with the pipe 66 .so that substantially the entire volume of iiuid from the pump 16 is conveyed to the table cylinder to assist tl'ie -pump 46 in traversing the table'II at a rapid rate. In all positions of the valve `above described, therev is suicient fluid escaping through the by-pass valve |45 to facilitate obtaining the desired fluid pressure within the chamber |49 of the hydraulic counterbalan'ce Y cylinder |411 It will be readily apparent from the foregoing disclosure that the upper pump 46 of the tandem pump is utilized to traverse the table I exclusively, whereas fluid from the lower pump 16 of the tandem pump is utilized to maintain a. pressure at all times within the counterbalance cylinder chamber |49 and during the normal table traverse to supplement the pressure from the pump 46 to reciprocate the table at a rapid rate and also during the period of reversal serves to actuate the fluid motor 96 to cause a transverse feeding movement of the wheel slide I6 and grinding wheel I5.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinbefore 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.

1. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally reciprocable work supporting table, a separatefuid motor for said slide and table, a separate control valve for each of said motors, a `uid pressure system including two motor driven pumps, operative connections. between one of said pumps and said table valve and motor to reciprocate the table, and operative connections between said second pump and said slide motor and valve to feed the wheel transversely at the end of the table stroke, said lat-` ter connections being arranged to connect the second pump with said table valve and cylinder during the normal reciprocatory movement of the table to supplement said first pump.

2. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally reciprocable table, a separate fluid motor for said slide and table, a

separate control valve for each of said motors, a

fluid pressure system including two motor driven fluid pumps, operative connections between one of said pumps and the table valve and cylinder to reciprocate the table, and means alternately to connect said second pump to said wheel slide motor during the table reversal period and to said table valve and cylinder during the normal reciprocatoryvmovement of said table.

3. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally reciprocable table, a separate fluid motor for said slide and table, 'a separate control valve for each of said motors, a uid pressure system including two motor driven fluid pumps, operative connections between one of said pumps and said table valve and cylinder to reciprocate the table, and operative connections alternately to connect said second pump tothe wheel slide valve and motor to feed the grinding wheel transversely at the end of the table stroke and to connect said second motor to said table valve and cylinder during the normal grinding stroke of said table.

4. Ina surface grinding machine, a rotatable grinding wheel, a transversely movable Wheel slide therefor, a vertically movable slide for said transverse slide, hydraulic counterbalance .for said vertical slide including a piston and cylinder, a longitudinally reciprocable table, a separate uid motor for said'wheel slide and table, a separate control valve for each of said motors, a fluid pressure system including two motor driven pumps, operative connections between one of said pumps and said table valve and cylinder to reciprocate said table, operative connections bctween said second pump alternately to connect said second pump to the wheel slide valve and 'motor to feed the Wheel transversely at the end' of the table stroke and to connect said second pump to said table valve and cylinder during the normal grinding stroke thereof, and operative connections between said second pump to maintain a uniform pressure in said counterbalance cylinder at all times.

5. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally reciprocable table, means including a reversing lever to reciprocate said table, a fluid pressure piston and cylinder operatively connected to traverse said slide,' a control valve to control the admission to and exhaust of fluid from said cylinder, a solenoid valve to control the exhaust of fluid from said valve and cylinder which is normally closed during reciprocation of said table, a limit switch on said reverse lever, dogs on said table to engage said limit switch to actuate the same and to shift the reversing lever, and an electrical time delay relay which is rendered operative when the reverse lever is shifted to energize said solenoid valve to permit exhaust of fluid from the slide cylinder and thereby cause a transverse traversing of the grinding wheel during the table reversal.

6. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a longitudinally reciprocable table, means including a reversing lever to reciprocate y said table, a fluid pressure piston and cylinder operatively connected to traverse said slide, a control valve to control the admission to and exhaust of fluid from said cylinder, a solenoid valve to control the exhaust of fluid from said valve and cylinder which is normally closed during reciprocation of said table, a limit switch actuated vin timed relation with said reverse lever, dogs on said table to shift the reversing lever, and an electrical time delay relay which is rendered operative when the reverse lever is shifted to energize said solenoid valve to permit exhaust of fluid from the slide cylinder and thereby cause a transverse traversing of the grinding wheel during the table reversal.

7. In a surface grinding machine, a rotatable grinding wheel, a transversely movable slide therefor, a vertical slide to support said transverse slide, a longitudinally reciprocable work supporting table, means including a manually operable nut and screw mechanism to feed said vertical slide in either direction to cause the grinding wheel to approach or recede from said work table, means including a reversible electric motor to actuate said nut and screw mechanism including a piston and cylinder operatively connected to the end of said screw, means to supply fluid under pressure to said cylinder, said pressure being sufficient to take up the backlash between the nut and screw and to assure the thrust between the screw and nut is always in the same direction regardless of whether the screw and nut are operated to move the slide up or down.

8. In a surface grinding machine, a rotatable grinding wheel, means including a vertical slide to support said wheel, manually operable means including a nut and screw mechanism to adjust the position of said slide and wheel in a vertical direction, means including a reversible electric motor to operate said nut and screw in either direction to cause an up or down movement of said slide and wheel, and a fluid pressure end thrust mechanism for said screw including a pis ton and cylinder operatively connected to the end of said screw, means to supply fluid under pressure to said cylinder, and means to adjust said pressure so that the screw and nut are always held in the same position relative to each other regardless of whether the nut and screw are actuated to cause an up or down movement of the slide.

9. In a surface grinding machine, a rotatable grinding wheel, means including a vertical slide to support said wheel, a manually operable feed mechanism for said slide including a rotatable nut which is held against endwise movement, a non-rotatable feed screw, connections between the upper end of said screw and said slide, means including a reversible electric motor to rotate said nut in either direction, a reversing switch therefor, and a fluid pressure end thrust mechanism for said screw including a piston and cylinder operatively connected to the lower end of said screw, means to supply fluid under pressure to said cylinder, and means including a manually adjustable valve to maintain a uniform pressure in said cylinder so that the thrust between the nut and screw is always in the same direction.

ALBERT G. BELDEN. CARL G. FLYGARE.

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