US2161150A - Grinding machine table reciprocating mechanism - Google Patents

Description

June 6, 1939, c. G. FLYGARE 2,161,150

GRINDING MACHINE TABLE RECIPROCATING MECHANISM Filed March 3, 1938 2 Sheets-Sheet l CARL G. FLvsA/z:

F7 1 mmuwemn June 6, 1939. c G FLYGARE GRINDING MACHINE TABLE RECIPROCATING MECHANISM 2 Sheets-Sheet Filed March 3, 1938 l /03 25 704 6 1 gwuwvto'o CARL G'. FLYGARE I /5.3 mmauumm Patented June 6, 1939 U ITE STATES PATENT OFFICE Application March 3, 1938, Serial No. 193,707

6 Claims.

' anism whereby a variable dwell may be obtained.

at either or both ends of the table reciprocation.

. A further object of the invention is to provide an electrically controlled dwell control for a table 15 reciprocating mechanism. A further object of the invention is to provide a hydraulically operated table reciprocating mechanism with an electrical time delay relay control therefor to control the extent of dwell at eachend of the table stroke.

20 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 behereinafter 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 combined hydraulic and electrical I diagram of the improved table. reciprocating mechanism; 1

Fig. 2 is a cross sectional view through the table reciprocating mechanism,.showing the valve actuating mechanism in cross section;

Fig- 3 is a longitudinal sectional view, on 'an enlarged scale, taken approximately on'the line 3+3 of Fig. 2; and Fig. 4 is a sectional view taken' approximately -'on the line 44 of Fig. 3. I v

. As illustrated in the drawings, the machine embodying this invention comprises a base 9 which supports a longitudinally reciprocable table 5 III on the usual V-way andflat way (not shown) for a longitudinal reciprocatory movement rela' tive to the base 9. I A fluid pressure operatedreciprocating mechanism is provided to reciprocate the table l0, com- 3 prising a fluid pressure cylinder II which is fixedly mounted to the under side of the table It. The cylinder l-l contains a pair of spaced pistons I2 and 13 which are connected by a pair of hollow piston rods l4 and I 5, respectively, with a pair of ;hollow brackets 16 and I1, respectively, mounted "onopposite ends of the base 9.

' In the preferred construction, the base 3 is fornfed with a hollow box-like construction, in

which-the lower portion serves s a reservoir 20 tor -the fluid pressure system. Fluid is drawn from the reservoir 20 through a pipe 2| by a. mo-

tor driven fluid pressure pump 22 and is forced through a pipe 23 and a; pipe or passage 24 to a table control valve 25. A fluid pressure relief valve 26 is provided in the pipe line 23 and is arranged to allow excess fluid under pressure to by-pass through a pipe 2'! into the reservoir 20 in case the pressure within the system increases above a desiredv predetermined pressure.

A control valve 25 is preferably of a' piston type reversing valve which includes a movable valve member 29 having formed integrally therewith a plurality of valve pistons 30, 3|, 32, 33 and 34. Fluid under pressure from the pump 22 is.forced through the pipes 23 and 24 into a valve chamber 31, between the valve pistons 3| and 32, and passes outwardly through'a pipe 39 into an aperture 40 in bracket l6, through the hollow piston rod l4 and piston l2, into a cylinder chamber 41 to cause thecylinder II and table to move in a direction toward the left (Fig. 1) During movement of the table toward the left, fluid within a cylinder chamber 42 is exhausted through the piston I 3, the hollow piston rod 15, an aperture 43 within the bracket I1, and through a pipe 44 into a valve chamber 38 between thevalve pistons 32 and 33, and out through'a pipe 45 which returns exhaust fluidthrough a pipe 46 into thereservoir 20.

A speed control valve 50, as illustrated in the drawings, is preferably formed integral with the valve 25. As illustrated in the diagram (Fig. 1),

the valve is shown as a separate valve unit. The

' valve 50 is preferably located in the exhaust side 0i. the system so as to maintain a uniformfluid pressure on the operative side of the main cylinder. This valve comprises a valve stem 5| which is provided with valve pistons 52 and 53. The casing for the valve 50 is provided with a V- shaped port 54 which is located at one end of the pipe line or passage 45, conveying fluid from 7 either the valve chamber 31 or 38,- depending upon the position of the valve 25. The passage or outlet pipe 46 serves to exhaust fluid from a' throttle valve chamber 5'! into the reservoir 20 within the base of the machine.

The throttle valve isarranged so that it may be moved longitudinally from a full line to a dotted line position. The valve is provided with an actuating knob 59 on the front end of the valve stem, 5| which facilitates rotation of the valve. In. the preferred construction, theend of the valve piston 53, instead of being a plane sur face at right angles to the axis of the throttle valve, is arranged at an angle thereto. By providing an angularly positioned end surface on the valve piston 53, any rotation of the valve member serves as a' fine adjustment to cut off more or less of the V-port 54precisely to regulate the exenable the table to be stopped and started as desired, without changing the speed adjustment, a serrated or notched portion is provided which is formed integral with the valve stem 5|. A spring pressed pawl BI is carried by the valve casing 50 so that when the knob 59 is rotated to adjust the valve piston 53 to give the desired table speed, the detent 6| engages notches in the serrated portion 60 and serves to hold the valve piston in its adjusted position so as to permit longitudinal or axial movement of the valve stem 5| by means of a control lever I0 to stop and start the table movement without upsetting the speed adjustment of the valve.

The control lever I0 is pivotally mounted on a stud 'II fixedly mounted on the base 9 of the machine and serves to permit a rapid movement of the valve stem 5| to stop-and start the table movement. The lever 10 is provided with an aperture I2 fitting loosely around a sleeve I3 which is mounted on the valve stem 5|. A pair of opposed aligned trunnion pins I4 are provided at opposite sides of the aperture 12 on the lever 10 and are arranged to engage vertical slots I5 in the sleeve 13. It will be readily apparent from the foregoing disclosure that when the throttle valve lever is in the position indicated in full lines, the valve stem 5| is positioned so that 'the valve piston 53 uncovers allor a portion of the V-port 54, allowing the table to move at a predetermined speed. By moving the lever 10 into position 10a, as indicated in broken lines in Fig. 1, thevalve piston 53 is moved into position 5311, thereby closing the V-port 54 and stopping the table movement. I

When the throttle valve is in a closed position .to stop the hydraulic table movement, it is desirable to provide a suitable fluid by-pass whereby fluid may readily pass from the cylinder chamber at one end of the cylinder to the cylinder chamber at the other end thereof to facilitate a manual traversing movement of the table.- In the preferred construction, a pipe or passage 80' is provided to connect the pipe 44 and the valve chamber 38 with a passage or pipe 8| provided as an extension of the pipe 39a. When the throttle valve 50 is in a closed position, as indicated in broken lines,- fiuid may readily pass from the cylinder chamber 4|, through the pipe 39, the pipe 39a, the pipe 8|, through a valve chamber 82 between the valve pistons 52 and 53, through the. pipe 90, the pipe 44, and into the cylinder chainber42.. This by-pass in the'throttle valve interconnects the cylinder chambers 4| and 42 so that when the fiuid pressure system is shut ofi by closing the throttle valve 50,- the table may then be readily moved manually, if desired."

A manually operable table traverse mechanism may be of the type shown in the prior United States Patent No. 2,071,677 and'may consist of a manually operable hand wheel and a rack and gear mechanism for moving the table longitudi nally.

A suitable reversing mechanism is provided to change the direction of movement of the table, as desired. In the preferred construction, adjustable table dogs and 9| are. adjustably mounted in a T-slot 92 on the table I0. The dogs 90 and 9| are arranged to engage a pin 89 on the upper end of a reverse control lever 93 whichis pivotally mounted on a stud 94 on the base 9 of the machine. Thelever 93 is operatively connected to move the valve stem 29.

In order that the table may be reversed with a minimum amount of vibration, it is desirable. to provide a lost motion connection between the reversing lever 93 and the reversing valve 25, so that during the initial movement of the reverse lever under the influence of the table dogs, the

valve is not moved. This mechanism preferably comprises a short lever 95 fixedly keyed to the inner end of the stud 94. -A short lever 96 is rotatably mounted on the stud 94 and is supported thereon by means 'of a bushing, so that the lever 96 is free to oscillate relative to the stud 94. The lever 96 carries a pin 91 engaging a groove 98 in an extended portion of the valve stem 29. The.

Assuming the parts of he reversing mechanism to be in the position illustrated in Fig.v 1, the table is moving in a direction toward the left, which movement continues until the reversing lever 93 is moved a suflicient distance to actuate the lever 95 through its lost motion movement until the aperture 99 engages the pin I00. This movement of the lever 95 relative to the lever 96 serves to compress the spring I05 and when the aperture 99 engages the pin I00, continued movement of the table serves to throw the reiversing valve stem 29 into a central or neutral position, as. indicated in Fig. 3, in which position the pressures are balanced on opposite sides of the main cylinder II. The compression of the spring I05 then tends to move the valve stem 29 toward the right, which movement is prevented by a means to be hereinafter described.

When the compression of the spring I05 is released, it shifts the valve from a centralorneutral position so as to uncover a port I II, decreasing the fluid pressure: passing into a chamber H2 9 valve stem 29 toward the right, as viewed in Fig. 3,

to throw thevalve into its extreme reverse position and thereby cause a reversal in direction of movement of fluid under pressure to pass the same to the opposite end of the main driving cylinder. II and .thereby cause the table I0 to .move in the opposite direction.

Due to the differential in the pressure areas between the valve pistons 30, 34 and 3|, 33, respectively, the chambers H3 and H2 function as a pilot valve to cause a reversal of the reversing valve under the influence of fluid under pressure. The reversing lever 93 serves only to causethe reversing valve to move to' a central or neutra position, as illustrated in Fig. '3, and the spring I05 then under compression serves to move the reversing valve slightly off center to change the respective openings of the ports 0 and III and cause fluid under pressure to operate through the chambers II! and M3 to cause a fluid pressure piping connections and losses due to passages between the various valves as experienced here-' I tofore.

Fluid within the valve chamber II2 may exhaust through a port I and similarly fluid Within the valve chamber II3 may exhaust through a port I2I, into reservoirs I22 and I23, respectively. When the valve piston 29 is moved to either end of its stroke, as shown in the diagrammatic illustration in Fig. 1, fluid within the chamber H3 is free to exhaust through port I2I, into the reservoir I23. Similarly, when the valve piston 29 is moved. toward the right, fluid within the valve chamber II2 may exhaust through the port I20, into the reservoir I22.

In--a cylindrical'traverse grinding operation, it is frequently desirable to provide a suflicient dwell of thetable at the end of its reciprocatory stroke so that the work-piece may rotate at least one complete rotation before the table stops its movement and starts in the reverse direction. The period of dwell necessary to accomplish this result varies, with the size of the work being ground, the width of the grinding wheel. being used, as well as the relative speeds of the work rotation and table reciprocation. It is, therefore, desirable to-provide a variable dwell at either or both ends'of the table stroke to accomplish the desired results. In-the preferred construction,

the dwell at'the end of the table stroke may be accomplished by interrupting the flow of fluid within the hydraulic system so as to allow the table to dwell at the end of its stroke for a predetermined adjustable time interval.

In the preferred construction, an electrical control mechanism is provided to delay the admission to or exhaust from one end of the table cylinder when the reverse valve is shifted so that a table dwell of any desired length may be obtained. This is preferably accomplished by means of a cut-off valve I30 whichis connected between the pipe 39 and a pipe 39a which is connected to the control valve 25. The ,valve 'I30 is preferably a piston type valve, which is normally held in an open positionby meansof a spring I3I and may be closed by means of an electric solenoid I32 which is connected by a link I33 with the outer end of a piston rod I34. The piston rod I34 has formed integrally therewith a pair of valve pistons I35 and I 36 which form a valve chamber I3'I therebetween. The casing of the valve I30 is provided with a plurality of V-' ports I38.which in the position illustrated in the drawings (Fig. -1) ,are wide open. When, the solenoid I32 is energized;' the valve stem I34 together with the valve pistons I35 and I36 are moved toward the left (Fig. 1) against the tension of the spring I3I to close the V-ports I38 and thereby prevent fluid from passing between the pipes 39 and 39a. The valve I30 is arranged example, it may be actuated in timed relation with the shifting of the reversing valve 29.

A rock arm I42 is pivotally mounted on a stud I43 which is fixedly supported on the base 9. One arm of the rock arm I42 is provided with an arrow pointed end I44 which is adapted to swing in the path of a roller I45 which actuates the limit switch I. The other end of the rock arm I42 is connected by astud I46 with a spoolshaped end ,I4I on a projecting portion of the valve 29. It will be readily' apparentfrom the foregoing disclosure that when a table dog oper ates through the reverse lever 93 to shift the valve 29 into its reverse position, the rock arm I42 is actuated thereby to swing the arrow point I44 over the roller I45 to depress the roller I45- and thereby instantaneously close the limit switch I4:I whibh serves to set the time delay relay I33 into operation and also serves simultaneously to energize the solenoid I32 to shift, the valve stem I 34 toward the left (Fig. 1) to close of fluid under pressure fromthe pipe 39a from entering the pipe 39 when'the table is traveling in one direction or to prevent the exhausting of fluid from the pipe 39 into the pipe 39a when the table is moving in the other direction. The valve I34 remains in a closed positionand the solenoid I 32 remains energized until a definite time inter-al, for which the time delay relay I33 has been set, whereupon the time delay relay serves to break the circuit and to deenergize the solenoid I32, thereby releasing the compressed spring I3I,

which rapidly returns the valve I 34 into the position shownin Fig. 1 to allow free passage of fluid between the pipes 39 and 39a. It will be readily apparent that the time limit switch I is instantaneously closed each time the valve 29- is shifted into a reverse direction,regard1ess' of which direction the valve is moved. Each time the limit switch MI is closed, the time delay relay I33 is set in motion and thesolenoid I32 is energized to prevent the passage of fluid between the pipes 39 and 390, so that regardless of whether fluid underpressure is being admitted toor exhausted from the cylinder chamber 4 I, the valve I30 being closed will prevent such movement of the fluid until the time delay relay automatically opens the circuit ,after' a predetermined time interval to deenergize the solenoid I32 andwthus permit the valve I30 to open and allow the table to start its movement in the reverse direction after a predeter mined interval of dwell.

The operation of this table reciprocating mechanism will be readily'apparent from the foregoing disclosure. Assuming all of the parts have been previously adjusted and the table is traversing in a direction toward the left (Fig. 1), this move ment continues until a projectionr I50 on the reversing dog 9| engages a pin or stud 89 on the reverse lever 93. Movement of the reverse lever in a counterclockwise direction serves through they parts above described to shift the valve 29 toward the right (Fig. 1) first to stop the table movement and then to shift into a reverse position so that fluid may be admitted to cause thetable I0 to traverse in the reverse direction. During the time the reverse valve 29 is shifting toward the rightto cut off fluid so as to stop the table movement, the rock arm I42 is rocked in a clockwise direction by movement of the valve 29 so that when the valve 29 reaches a central or neutral position, the arrow point 44 has depressed the roller I45 and closed the limit switch I 4|, which closing serves to."set the time delayrelay I33 in i "valve. and one end of said cylinder for apredeteroperation and simultaneously to energize the solenoid I32 to close the V-ports I38 so that when the control valve, 29 reaches its .reverse position, fluid under pressure entering the pipe 44 cannot start the table moving in the reverse direction until a definite time interval has elapsed due to the fact that the V-ports I38 are closed and fluid within the cylinder chamber 4| cannot. exhaust through the pipe 39 into the pipe 39a. The table thus remains stationary for a predetermined time interval until the electrical time delay relay I33 operates again to deenergize the solenoid I32 so as to allow the released compression of the spring I3I to. shift the valve stem I34 and open the V-ports I38, which movement allows the fluid within the chamber 4| to exhaust and the table to start its movement in the reverse direction.

It will be readily apparent from the foregoin disclosure that the limit switch III is actuated each time the valve 29 is shifted regardless of which direction the valve is moved to operate the time delay relay and energize the solenoid I32 to prevent the passage of fluid between the pipes 39 and 39a to cause a predetermined adjustable dwell at each end of the table stroke.

By manipulation of the adjustable time delay relay I33, the dwell at each end of the table stroke may be adjusted as desired.

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:

1. In a grindingmachine, a longitudinally re-' ciprocable table, means including a fluid pressure piston and cylinder to reciprocate said table, means including a reversing valve to control the admission of fluid to said cylinder, a lever operatively connected to move said valve, adjustable dogs on said table to move said lever and shift the valve into a reverse position, and an electrically controlled mechanism which is actuated by and in timed relation with the movement of said reverse valve to prevent the flow of fluid between said reverse valve and one end of said cylinder until the table has stopped for a predetermined period of dwell.

2. In a grinding machine, a longitudinally reciprocable table, means including a fluidpressure piston and cylinder to reciprocate said .table, means including a reversing valve to control the admission of fluid to said cylinder, a lever operatively connected to move said valve, adjustable dogs on said table to move said lever and shift the valve into a reverse position to stop and reverse said table. movement, and an electrically controlled time delay mechanism which is actuated by and in timed relation with said reversing valve to prevent the flow of fluid between saidreverse i. mined time interval before allowing the table to start moving in the opposite direction.

3. In a grinding machine, a longitudinally reciprocable table, means including a piston and 1 cylinder to reciprocate said table, means including afzreversin'g valve to control the admission of fluid to said cylinder, a lever operatively connected to move said valve, adjustable dogs on said table 'to move said lever and shift the valve into a reverse position to stop and reverse the table movement, an electric switch actuated by said reversing valve, and means including an electric time delay relay which is set in motion by said switch to prevent the flow of fluid between the reversing valve and one end of said cylinder for a predetermined time interval before allowing the table to start moving in the opposite direction.

4. In a grinding machine, a longitudinally reciprocable table, means including a piston and cylinder to reciprocate saidtable, means including a reversing valve to control the admission of fluid to said cylinder, a lever operatively connected to move said valve, adjustable dogs on said table to J move said lever and shift the valve into a reverse position to stop and reverse the table movement,

an electric switch actuated by said valve, a solenoid valve which is closed by said switchto prevent the flow of fluid between the reversing valve and said cylinder, and an electrical time delay relay which is actuated by said switch to operate said solenoid valve to start the table moving in the reverse direction after a predetermined period of dwell.

5. In a grinding machine, a longitudinally reciprocable table, means including a piston and cylinder operatively connected to reciprocate said table, a reversing valve therefor which is arranged to admit fluid under pressure to either end of said cylinder, a pair of adjustable dogs on said table, a

reversing lever operatively connected to said valve and arranged to move said valve into a reverse position when ated upon by one of said dogs, an electrically controlled valve which is operatively connected between said reversing valve and said cylinder, a switch actuated by said reversing valve to close said electrically controlled valve, and a time delay relay rendered operative by said switch to open said electrically controlled valve after a predetermined time interval and thereby permit the flow of fluid between the control valve and one of said cylinders so as to start the movement of the table in the reverse direction.

6. In a grinding machine, a longitudinally reciprocable table, means including a piston and cylinder operatively connected to reciprocate said table, a reversing valve associated therewith and arranged to admit fluid under pressure to either end of said cylinder, a reversing lever operatively connected to move said valve, adjustable dogs on said table which are arranged to actuate said lever to shift the reversing valve into a reverse position,

- a solenoid controlled valve interposed between sage of fluid between the reverse valve and said cylinder, and an electrically operated time delay relay set in motion by the closing of said switch which serves after a predetermined time interval to open a circuit and deenergize said solenoid'to open said solenoid valve and allow passage of fluid between the reversing valve and said cylinder to start the table moving in the reverse direction after a predetermined period of dwell.

' cARL G. FLYGARE,

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