US2268389A - Grinding machine-table reciporcating mechanism - Google Patents

Description

Dec. 30, 1941. J l, smE 2,268,389

GRINDING MACHINE-TABLE RECIPROCATING MECHANISM Filed May 14, 1940 3 Sheets-Sheet l J0 HN [5HH5/DE WD-ELL-n Dec. 30, 1941. J- I. GARSIDE GRINDING MACHINE-TABLE RECIPROGATING MECHANISM Filed May 14, 1940 3 Sheets-Sheet 2 Dec. 30, 1941. J. 1. GARSIDE GRINDING MACHINE-TABLE RECIPROCATING MECHANISM Filed May 14, 1940 3 Sheets-Sheet 3 a m M dwell control switches which are Patented Dec. 30, 1941--- GRINDING MACHINE-TABLE RECIPRO- CATING MECHANISM John I, Garalde, West Boylston, Mass, assignor to orcester, Masa, a corporation of Massachusetts Application May 14, 1940, Serial No. 335,111

Norton Company, W

9 Claims.

The invention relates to grinding machines, and more particularly to a hydraulically operated table reciprocating mechanism for a grinding machine.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated table reciprocating and reversing mechanism. Another object of the invention is to provide a table reversing mechanism with an improved dwell control mechanism. A further object of the invention is to provide a hydraulically operated table reversing mechanism with a variable dwell control whereby a variable dwell may be obtained at the ends of the table reciprocation.

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

A further object of the invention is to provide a dwell control mechanism in which the table movement serves to shift a control or reversing lever to a central or neutral position and a time delay mechanism serves to control the admission of fluid under pressure to complete the reversal of said valve. 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 exemplitied 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. l is a combined hydraulic and electric diagram of the improved table reciprocating mechanism;

Fig. 2 is a cross sectional view through the table reciprocating mechanism, showing the reversing lever, reversing valve and the parts actuated by said lever;

Fig. 3 is a fragmentary elevation showing the arrangement of the reversing valve and the actuated by movement of the table reversing lever;

Fig. 4 is a cross sectional view, on an enlarged scale, through the manually operable table traversing mechanism;

Fig. 5 is a fragmentary sectional view, taken approximately on the line 5-5 of Fig. 4; and

Fig. 6 is a fragmentary sectional view taken approximately on the line 6-8 of Fig. 4.

As illustrated in the drawings, the machine embodying this invention comprises a base Ill which supports a longitudinally reciprocable table II on the usual V-way (not shown) and flat way 9 for a longitudinal reciprocatory movement relative to the base III.

A fluid pressure operated reciprocating mechanism is provided to reciprocate the table II comprising a fluid pressure cylinder l2 which is fixedly mounted on the under side of the table II. The cylinder 12 is provided with a pair of spaced pistons l3 and M which are connected by a pair of hollow piston rods [5 and it, respectively, with a pair of hollow brackets l1 and i8, respectively, mounted on opposite ends of the base l0.

In the preferred construction the base I0 is formed with a hollow, box-like construction in which the lower portion forms a reservoir 20 through a pipe 2| by a motor driven fluid pressure pump 22 which forces the fluid through a pipe 23 and a pipe or passage 24 to a table control valve 25. An adjustable 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 21 into the reservoir 20 in case pressure within the system increases 7 above a desired and predetermined pressure.

pistons 30 and 3i.

The table control or reversing valve 25 is preferably a piston type reversing valve which includes a valve stem 29 having formed integrally therewith valve pistons 30, 3| and 32. A valve chamber 22 is formed between the valve piston III and the left-hand end cap of the valve 25. A valve chamber 34 is formed between the valve A valve chamber 35 is formed between the valve pistons 3| and 32 and a valve chamber 35 is formed between the valve piston 22 and the right-hand end cap of the valve 25. Fluid under pressure from the pump 22 is forced through the pipe 23 and the pipe or passage 24 into the valve chamber 34, between the valve pistons 30 and 3|, and passes outwardly through a pipe 39 into a passage 40 formed within the bracket I8, through the hollow piston rod l6 and piston l4, into a cylinder chamber 4|, to cause the cylinder I2 and the table II to move in a direction toward the right (Fig. 1). During movement ofthe table II toward the right, fluid within a cylinder chamber 42 is exhausted through the piston IS, the hollow piston rod l5,

a passage 43 formed through a pipe 44 within the bracket I1, and

into the valve chamber 35 located between the valve pistons 3| and 32, and out through a pipe 45 which returns exhaust fluid through a' pipe 45 into the reservoir 20.

A speed control valve 55 (Fig. 1) is preferably formed integral with the table reversing valve 25. As illustrated in the diagram (Fig. 1), the valve is shown as a separate valve unit. The valve 5|! is preferably located in the exhaust side of the system so as to maintain a uniform pressure on the operative side of the main cylinder. The valve 50 is preferably connected between the pipes 45 and 45 so as to control the fluid exhausting from the table reversing valve 25. The valve 50 comprises a valve stem 5| which is provided with valve pistons 52, 53 and 54. The valve pison 52 is provided with a V-shaped notch 55 which serves as a V-port. In the position illustrated in Fig. 1, the V-port 55 is located in an operative position opposite the port at the end of the pipe 45 which throttles fluid flowing either from the valve chamber 34 or 35, depending upon the position of the valve 25. The passage or exhaust pipe 45 is operatively connected to convey fluid exhausting through the V-port 55 from the throttle valve 50 into the reservoir 25 so as to control the speed of movement of the table II.

The throttle valve 5|) is arranged so that it may be moved longitudinally and is provided with an actuating knob 59 on the front end of the valve stem 5| which facilitates either an endwise or a rotary movement of the valve stem 5|. A rotary movement of the valve stem 5|, in the position illustrated in Fig. 1, causes the V-port 55 to vary the exhaust aperture whereby fluid exhausting from the pipe 45 may pass through into the exhaust pipe 45 and serves precisely to adjust and to regulate the exhaust of fluid from the system and thereby provide a fine and precise regulation of the table speed.

In order that the valve piston 52 together with its V-port 55 may be maintained in the desired adjusted position so as to enable the table II to be stopped and started as desired, without changing the speed adjustment, a serrated or notched portion 50 is provided which is formed integral with the valve stem 5|. A spring-pressed, arrow-pointed detent 5| is carried by the valve casing 50 so that when the knob 59 is rotated to adjust the valve piston 52 to produce the desired and predetermined table speed, the-detent 6| engages notches in the serrated portion 65 and serves to hold the valve piston 52 andthe V-port 55 in its adjusted rotary position so as to permit longitudinal or axial movement of the valve stem 5| by means of the control knob 59 to start or stop the table movement without upsetting the speed adjustment of the valve 50.

If it is desired to stop the table movement, the knob 59 is moved toward the right (Fig. l), which movement causes the valve stem 5| together with the V-port 55 also to move toward the right so that the V-port 55 is moved out of line with the port at the end of the pipe 45, thus preventing any exhaust of fluid from the table reciprocating cylinder l2 and thus holding the table II in a stopped position.

In order to facilitate a manual traversing movement of the table II by any of the old and well known table traverse mechanisms (not shown), it is desirable to provide a fluid by-pass in the diydraulic system whereby fluid may readily pass from the cylinder chamber 4|. at one end of the table cylinder to the cylinder chamber 42 at the other end thereof to facilitate an unrestricted manual traversing movement of the table II. In the preferred construction, a pipe or passage 52 is provided to connect the pipe 44 and end valve chamber 35 with the valve 55. Similarly, a pipe or passage 53 connects the pipe 33 and valve chamber 34 with the valve 55. The pipes or passages 52 and 53 are arranged on opposite sides of the valve 50. When the throttle valve 50 is moved toward the right to close the v-port 55 and thus stop the hydraulic traversing movement of the table II, a valve chamber 54 located between the valve pistons 53 and 54 is moved into alignment with ports at the ends of the pipes 52 and 53 so that fluid within the cylinder chamber 4| may pass through the e 40, the pipe 39, the valve chamber 34, the pipe 53, the valve chamber 54. the pipe 52, the valve chamber 35, the pipe 44, and the passage 43, into the cylinder chamber 42. thus providing a direct by-pass of fluid to facilitate a manual traversing movement of the table l.

When the hydraulic movement of the table II is stopped, it is desirable to provide suitable means for preventing the building up of pressure within the pipe 23 from the pump 22. In order to overcome this difliculty, an unrestricted by-pass to the reservoir is provided. The throttle valve 50 is provided with a valve chamber 55 which is located between the valve pistons 52 and 53. When the valve 55 is moved toward the right (Fig. 1) to stop the hydraulic movement of the table, the valve chamber 55 is also moved toward the right so that fluid under pressure entering the pipe or passage 24 may pass outwardly through a pipe 55, through the valve chamber 55, and exhaust through the exhaust pipe 45 into the reservoir 25.

Manual table traverse A manually operable table traverse mechanism is provided, preferably 01' a multi-speed type, whereby the table may be traversed manually at a comparatively rapid rate to position the table and a work piece supported thereon relative to the grinding wheel, or may be traversed at a relatively slow rate of speed during a grindthe well known speed reducing units. The unit I illustrated, however, is the well known heliocentric speed reduction unit 13, manufactured by the Universal Gear Corporation of Indianapolis, Indiana. The heliocentric unit 13 is rotatably supported in bearings '14 and 15 which are carried by an apron 15. The driven or input shaft 12 of the heliocentric unit 13 carries a pair of eccentrics ||1| and I02. A rotatable output or driven shaft 11 is fixedly mounted to a rotatable plunger holder I03 which travels within a stationary internal gear or rack member which is preferably divided into internal annular racks I04 and I05. The plunger holder I03 travels within the stationary racks I04 and I05 at the rate of one tooth for each rotation of the input shaft 12. The plunger holder M3 is slotted radially and carries a plurality of reciprocable plungers I05 and II" which are arranged to work into and out of mesh with two parts, namely the I messes minimum friction to the plunger holder I and the output or driven shaft 11. The input eccentrics III and I02 force the plungers out under load. A pair of retracting rings I00 and I09 ride in notches formed within the plungers I09 and I01, respectively, to hold back on the no load part of the cycle of operation.

A single eccentric or set of plungers and stationary rack may be employed, but for a maximum smoothness of operation and balance of the working parts, a Universal heliocentric reducer is employed, having two eccentrics as illustrated, each of which actuates a set of plungers in operative engagement with a pair of stationary racks. Each set of plungers is timed directly opposite or 180' apart and has a carrying arc of approximately 120. The total effect is a balanced distribution of driving power over twothirds of the complete cycle so that a balanced and uniform slow rotation of the output or driven shaft 00 serves to rotatethe eccentric or crankpin 00 to oscillate the heads 25 and 21 simultaneously in opposite directions to cooperate with the combined planetary and rotary movements of the lapping wheels 20 and 20 to produce a very slow uniform traversing movement of the work supporting table II.

The heliocentric unit I3 is provided with an output shaft 11 which has a gear keyed thereon. The gear 10 meshes with a rotatable idler gear I9 which is rotatably supported on a shaft 00. The gear I9 meshes with a gear 0I which is keyed on a rotatable shaft 02. The shaft 02 is journalled in bearings 03 and 04 which are sup: ported in a bracket 05 fixedly mounted on the apron 10. The shaft 02 rotatably supports a gear 00 which meshes with a rack bar 01 depending from the under side of the table II. The shaft 02 also supports a clutch member 00 which is slidably keyed thereon and which is arranged to be moved into and out of mesh with clutch teeth 09 formed integral with the gear 06. When the clutch 00 is disengaged from the clutch teeth 09, no rotary motion will be imparted between the shaft 02 and the gear 00. g

It is desirable that during the hydraulic traverse of the table II, the hand traverse mechanism be rendered inoperative. In order to accomplish this result, a hydraulically operated mechanism is' provided comprising a cylinder 90 having a slidably mounted piston 9| which is arranged to engage and actuate a rock arm 02. The rock arm 02 is pivotally supported by a stud 00 which is in turn fixedly supported on the bracket 00. The upper end of the rock arm 02 is yoke-shaped and is provided with spaced diametrically opposed studs 94 which ride in a groove 90 formed in the periphery of the clutch member 00. A spring 96 interposed between the lower end of the rock arm 92 and a depending projection 01 formed integral with the cylinder 00 normally tends to hold the clutch 00 in engagement with the clutch teeth 09. When the fiuid pressure by-pass from the chamber 20 through the pipe 00 to the reservoir 20 is out off gear I00.

so that fluid is conveyed through the control valve 20 to the table cylinder I2, fluid under pressure is also passed from the chamber 24 through a pipe into the cylinder '90 to move the piston 9| toward the right (Fig.- 4) to disengage the clutch member 00, thus rendering the hand traverse mechanism inoperative. The clutch mechanism and the hydraulic means for operating the same is shown diagrammatically in Fig. 1. Less power is required to operate the clutch 00; consequently the clutch will be disengaged before the table is set in motion.

A clutch mechanism is provided between the hand wheel I0 and the heliocentric unit 10, comprising an internal ring gear 99 which is fixedly mounted to the hub II to rotate with the hand wheel I0. A gear I00 of the same pitch diameter as the gear 99 is fixedly mounted to the heliocentric casing 10. When the hand wheel is in the position illustrated in Fig. 4, the ring gear 99 meshing with the gear I00 operatively connects the hand wheel with the housing I0 of the heliocentric unit so that when a rotary motion is imparted to the hand wheel I0, it will rotate the heliocentric unit 10 and transmit a one to one rotation between the hand wheel "I0 and the gear 10 which in turn transmits rotation through the'clutch members 00-09 to rotate the gear 00 and thus impart a longitudinal traversing movement to the rack bar 01 and the table II.

If a slow traversing movement of the table is desired, the hand wheel is moved toward the left (Fig. 4) to disengage the ring gear 00 from the A binder or clamping screw 00 is tightened to lock the heliocentric casing 10 relative to the apron I0. In this condition of the parts, any rotary motion of the hand wheel I0 is transmitted through the shaft I2 which operates through the speed reduction unit to impart a slow rotary motion to the output shaft I1 which in turn transmits a rotary motion through the gear mechanism above described and through the clutch parts 0000 to rotate the gear 00 and thereby transmit a slow traversing movement to the rack bar 01 and the table II.

Table reverse mechanism A suitable reversing mechanism is provided to change the direction of movement of the table automatically as desired. In the preferred construction, adjustable table dogs H0 and III are adjustably mounted in a T-slot I I2 formed in the front edge of the table II. The dogs H0 and III are arrangedto engage a stud IIO which is fixedly mounted on the upper end of a reverse control lever Ill. The reversing lever Ill is fixedly mounted on the forward end of a rock shaft H0 which is journalled in a bearing II9 formed in an apron III which is in turn fixedly mounted on thebase I0 of the machine. A rock arm H0 is fixdly 'mounted on the inner end of' the shaft IIO (Fig. 2). The upper end of the rock arm Ill is formed as a yoke-shaped member IIO having diametrically opposed studs I20 and I2I which engage a groove I22 formed in a spool-shaped member I20. The spool-shaped member I20 is fixedly mounted on the end of the valve stem 20 of the table reversing valve 20. It will be readily apparent from the foregoing disclosure that when the reversing lever I I4 is moved in either direction by either the table dog III or III, a rocking motion will be imparted to the shaft H5 which will in turn transmit a rocking motion through the yoke-shaped member III to the studs I20 and I2I to shift the valve stem It should be noted that the valve pistons 30 and 32 of the control valve 25 are wide faced pistons and are preferably so arranged that when Table dwell control In order to obtain a dwell of a predetermined extent at the ends of the table stroke, a suitable hydraulically operated, electrically controlled mechanism is provided to control the shifting movement of the valve 25 from a neutral position into the reverse position. A pipe I25 is connected between the pressure pipe 23 and. an electrically controlled, normally closed valve I26. The valve I 26 is a piston type valve comprising a valve stem I21 having pistons I28 and I29 formed integrally therewith. The valve I26 is normally held in a left-hand end position (Fig. 1) by means of a compression spring I30 which surrounds the valve stem I21 and is interposed between the piston I29 and the end cap at the right-hand end of the valve I26. A solenoid I3I is operatively connected so that when energized it will shift the valve stem I21 toward the right (Fig. 1) so that fluid under pressure passing through the pipe I 25 enters a valve chamber I32 located between the valve pistons I28 and I29 and passes outwardly through a pipe I33. The pipe I33 is connected with the end chamber 33 of the table control valve 25. In the position of the parts as illustrated in Fig. l, fluid may exhaust through the pipe I33, the valve chamber H3, and through an exhaust pipe I34 into the reservoir 20.

Similarly, the pipe I25 is connected with an lectrically controlled, normally closed valve I36. The valve I36 is substantially the same in construction as the valve I26 and comprises a valve I stem I 31 having valve pistons I38 and I39 formed integrally therewith. A compression spring I40 serves normally to hold the valve stem I31 in its right-hand end position (Fig. 1). An electric solenoid MI is operatively connected to the valve stem I31 and is arranged so that when energized it will shift the valve stem I31 toward the left so that fluid under pressure passing through the pipe I25 will enter a valve chamber I42 located between the valve pistons I38 and I39 and pass outwardly through a pipe I43. The pipe I43 is connected with the end chamber 36 of the table control valve 25 so that when fluid is admitted through the pipe I23 into the chamber 36, the table control valve 25 will be moved rapidly under the influence of fluid under pressure into its extreme left-hand end position (Fig. 1).

An electrically operated control mechanism is provided which is preferably actuated and controlled by and in timed relation with the movement of the table reversing lever. An electrical Iime delay relay I 45 is provided for controlling the solenoids I3I and MI. The time relay I45 may be any of the standard electric time relays such as, for example, the Microfiex time relay manufactured by Eagle Signal Corp. of Moline, Illinois.

The rock arm II8 which is supported on the inner end of the rock shalt III (Fig. 2) his t downwardly extending arm I48 which is fixedly mounted relative to the shaft I II and moves with the table reversing lever H4. The lower end 0! the arm I46 is provided with a roller I41. The roller I41 is arranged to engage a cam I48 which is carried at one end of a rock arm I49. The rock arm I49 is pivotally mounted on a stud I50. The movement of the rock arm I49 in a counterclockwise direction is limited by a stud I5I which is fixed relative to the base of the machine. The arm I49 supports an adjustable screw I52 which is arranged to engage the actuating plunger I 53 of a normally open limit switch I54. The limit switch I54 is operatively connected with the time relay I45 so that when the reversing lever is shifted, the roller I 41 will engage the cam I48 and rock the rock arm I49 in a clockwise direction so as to close the limit switch I54 and start the time relay I45.

A normally closed limit switch I55 is mounted on the frame I56 and is provided with an actuating plunger I51. The plunger I51 is arranged to be actuated either by a rock arm I58 which is pivotally supported by a stud I59 or by a rock arm I which is pivotally supported on a stud I6I. The rock arms I58 and I60 are provided with upwardly extending projections I62 and I63, respectively. The projecting bosses I62 and I63 support a pair of screws I64 and I65, respectively, which are arranged in the path of the actuating roller I41 at the lower end of the lever I46 which moves with the reversing lever H4. The inner ends of the rock arms I58 and I60 are arranged in the path of theactuating plunger I51 of the limit switch I55. When the reversing lever I I4 is shifted into its reverse position in either direction, the roller I41 engages either the screw I64 or the screw I65 and rocks either the arm I58 in a counterclockwise direction or the arm I60 in a clockwise direction to produce an upward movement of the plunger I 51 so as to open the switch I35 at the end 01 the stroke of the reversing lever II4. By adjusting the screws I64 and I65, the time of opening the limit switch I55 at each end of the movement of the reverse lever I I4 may be varied as desired.

In order that the time relay I 45 may operate at each end of the table stroke respectively to control the solenoids I3I and I, an electric switch mechanism is provided including a reversing switch I10 which is actuated by and in timed relation with the movement of the reversing lever H4. The downwardly extending arm I48 is provided with a rearwardly projecting stud "I (Fig. 2) which is arranged to engage a V-shaped notch formed in the upper end of a rock arm I12 which in turn serves as an actuating lever for the reversing switch I10. In Fig. 1 the switch I10 has been illustrated directly in back oi the reversing lever H4 and has also been shown diagrammatically in the same view so as to clarify the electrical wiring connections therewith. A magnetic switch I13 is interposed between the reversing switch I10 and the solenoid I3I to control the setting in motion 01' the time relay I45 to energize the solenoid I 3i Similarly, a magnetic switch I14 is interposed between the reversing switch I10 and the solenoid I so as to render the time relay I45 operative to control the energization of the solenoid I4I when the table II is at the other end of its reciprocatory stroke.

Operation The operation of the table traversing and reciprocating mechanism will be readily apparent from the foregoing disclosure. Assuming the valves and switches are positioned as'illustrated in Fig. 1, fluid under pressure from the pump 22 passes through the pipe 23 into the passage 24 and through the valve chamber 34, out through the pipe 39, into the cylinder chamber 4|, to cause the cylinder I2 and table II to move toward the right (Fig. 1). The movement of the table II toward the right continues until the table reversing dog III] engages the stud II3 on the reversing lever H4 and rocks the lever H4 in a clockwise direction (Fig. 1) The table II continues its movement toward the right until the table dog III] moves the reversing lever II4 a suflicient distance so that valve piston 30 covers the port at the right-hand end of the passage 24 (the valve piston 32 already covering the port at the right-hand end of the passage 24), which movement stops the movement of the table II by cutting off fluid under pressure from both the pipes 39 and 44. During the clockwise shifting movement of the reversing lever III, the roller I41 engages the cam I48 and rocks the rock arm I49 in a clockwise direction. This movement of the arm I49 depresses the plunger I53 to close the normally open limit switch I54. The closing of the limit switch I54 serves through the electrical connections diagrammaticaly illustrated in Fig. 1 to set in motion the electrical time delay relay I45.

The table II is held in a stationary position for a predetermined time interval as determined by the setting of the time relay I45. After the time interval has elapsed, the time relay I45 closes the magnetic switch I13 which instantaneously energizes the solenoid I3I to shift the valve I26 toward the right (Fig. 1), which movement opens the valve so that fluid under pressure direct from the pump 22 may pass through the pipe I25, the valve chamber I32, and the pipe I33, into the end chamber 33 of the table control valve 25 to rapidly shift thetable control valve stem 29 together with the reversing lever II4 toward the right (Fig. 1) to shift the valve from a neutral position into the reverse position so that fluid under pressure from the pump will pass through the pipe 44 into the cylinder chamber 42 to start the table II moving in the reverse direction.

As the lever II4 swings in a clockwise direction rapidly into the reverse position, the roller I41 engages the screw I64 and rocks the rock arm I58 in a counterclockwise direction on its supporting stud I59, which movement raises the plunger I51 to open the normally closed limit switch I55 which opens a circuit to deenergize and open the magnetic switch I13. The opening of the magnetic switch I1 deenergizes the solenoid I3I, thus allowing 9. released compression of the spring I39 to return the valve I26 to the position illustrated in Fig. 1. At the same time the magnetic switch I13 opens, the time relay I45 automatically resets itself ready for the next operation. The magnetic switch I13 is operatively connected in such a manner that when the switch I13 is closed by the closing of the normally open limit switch I54, the switch I13 will remain closed even though the reversing switch H is shifted during the movement of the reversing lever II4 toward and into its reverse position.

As soon as the reversing valve 25 has completed its reverse movement, fluid under pressure from the pump 22 passing through the pipe 23 and the passage 24 will pass through the valve chamber 35, the pipe 44, into the cylinder chamber 42, to cause the cylinder I2 and table II to start its traversing movement toward the left (Fig. 1). The table II continues its movement toward the left until the table dog III engages the stud I I3 on the reversing lever I I4 and moves the reversing lever H4 in a counterclockwise direction, which movement shifts the reversing valve 25 so that the valve pistons 30 and 32 cut oifthe admission of fluid under pressure from the passage 24 to stop and hold the table I I stationary for a predetermined period of dwell as governed by the setting of the electrical time delay relay I45.

During the shifting movement of the reversing lever H4 in a counterclockwise direction, the roller I41 again engages and moves the cam I48 to depress the rock arm I49, thus closing the normally open limit switch I54 which closes a circuit to close the magnetic switch I14 and at the same time starts the time relay I45 in motion. After a predetermined time interval, the electric time relay I45 energizes the solenoid I4I to shift the valve I36 toward the left (Fig. 1) so that fluid under pressure from the pipe I25 may pass through the valve chamber I42 and through the pipe I43 into the end chamber 36 of the main control valve 25 rapidly to shift the control valve stem 29 toward the right into the position illustrated in Fig. 1, thus reversing the direction of flow of fluid under pressure to the table cylinder I2. When the reversing lever II4 has completed its movement in a counterclockwise direction, the roller I41 engages the screw I to rock the arm I60 in a clockwise direction on its supporting stud I6I as a pivot to raise the plunger I51, thus opening the normally closed switch I55 to open the magnetic switch I14, thereby deenergizing the solenoid I2I so that the released compression of the spring I40 shifts the valve I36 into the position illustrated in Fig. 1. At the same time the switch I14 opens, the electric time relay I45 resets automatically so that it is ready to function at the next reversal in direction of the movement of the table II.

When it is desired to stop the hydraulic reciprocation of the table II, the knob 59 is moved toward the right (Fig. 1) to shut off the exhaust of fluid through the pipe 45 and thus stop the table movement. 50 opens the valve chamber 65 connecting the pipe 66 with the pipe 46 so that fluid under pressure from the pump 22 is returned directly into the reservoir 20. This direct by-pass of the fluid releases the compression of the spring 96 which automatically serves to engage the clutch member 36 with the clutch teeth 89, thus automatically rendering the manually operable traverse mechanism operative.

If a rapid manual traversing movement of the table II is desired, the clamping screw 63 is released, thus permitting rotation of the housing 13 of the speed reduction unit. A rotary motion of the hand wheel 10 will then be transmitted to rotate the entire speed reduction unit on its supporting bearings 14 and 15 to transmit a rotary motion to the table rack 81 to move the table II longitudinally at a comparatively fast speed. If a slow traversing movement of the table is'desired, the clamping screw 68 is tightened to hold the housing 13 of the speed reduction unit against rotation and the hand wheel 10 is moved toward the left (Fig. 4) to This movement of the valve passes through the pipe II I fvarious objects hereinabove set forth disengage the clutch gears "-4". In this chambers iormed at opposite ends of said revers position oi the parts, rotation at the hand wheel ing valve, a pair of control valves which are norwill transmit a rotary motion through the mally closed to the supply of fluid under pressure input shalt II of the speed reduction unit" but open to exhaustfluid from said end chamwhich will transmit a very slow rotation to the li hers which are arranged to control the admisoutput shaft II. The output shalt 11 will transsion of fluid lmder pressure to said end chambers mit this slow rotary motion through the gear respectively, and-means including an adjustable mechanism and clutch mechanism above detime delay relay which is rendered operative by scribed to rotate the gear ll slowly so as to imsaid control lever, said time relay being operpart a slow trav movement to the rack 10 atively connected to actuate one oi said control bar I! and the table II.

When it is desired to again start the hydraulic reciprocating movement 01 the table II, the knob I! is again moved toward the lstt (Fig; 1) to position the valve '0, as illustrated in 11g. 1, so that fluid under pressure from the pump passing into passage is passes through the valve! and either the pipe I! or the pipe 44 to the table cylinder. At the same time, into the cylinder. to move the clutch member it out of eng soment with the clutch teeth I, thus rendering the hand traversing mechanism inoperative.

Itwillthusbeseenthattherehasbeenprovided by this invention apparatus in which the e th with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made or 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 faith or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine, a longitudinally movable table, means including a piston and cylinder to reciprocate said table, a reversing valve therefor, means including a table actuated lever to move said valve to a central or neutral position to stop the table, an end chamber formed at each end or said reversing valve, a pair of control valves to control the admission of fluid under pressure to said end chambers respectively, and means including an adjustable time delay relay which is rendered operative by movement of said lever, said time relay being operatively connected to open one 01' said control valvu after a predetermined time interval to admit fluid under pressure rapidly to shii't the reversing valve into a reverse position. 7

2. In a grinding machine, a longitudinally movable table, means including a piston and cylinder to reciprocate said table, a reversing valve therefor, means including a. table actuated lever to move said valve to a central or neutral position to stop the table, an end chamber formed at each end of said reversing valve, a pair of solenoid valves to control the admission of fluid under pressure to said end chambers respectively, and means including an adjustable electrical time delay relay which is rendered operative by movement' of said lever, said time relay being operatively connected to open one or said solenoid valves after a predetermined time interval to admit fluid under pressure to one of said end chambers rapidly to shift the reversing valve into a reverse position.

3. In a grinding machine, a longitudinally movable table, means including a piston and cylinder to reciprocate said table, a reversing valve therefor, a supply 01' fluid under pressure, means including a control lever to move said valve to a to one of said end fluid under presalre movable table, means actuated by said lever valves to admit fluid under pressure to one oi said end chambers rapidly to shift the re valve into a reverse position. a v

4. In a grinding machine, a longitudinally movable table, means including a piston'and cylinder to. reciprocate said table, therefor, end chambers formed of said reversing valve, a supply oi fluid under pressure, means including a control lever to actuatesaid valve, trically controlled valves, one or said valves being connected in a pipe line between the fluidpres suresupplyandanendchamberatoneendot the reversing valve, the other oi said valves being connected in a second pipe line between said fluid pressure supply and a chamber at the other end of the reversing valve for controlling the shitting of the valve into justable time delay relay which is rendered operative by said control lever, and means actuated by said lever to render one oisaid electrically controlled valves operative when the control lever is moved in one direction and to render the other control valve operative when the lever is moved in the opposite direction.

5. In a including a piston and cylinder to reciprocate said table, a reversing valve therefor, end chambers formed at opposite ends of said reversing valve, a supply of fluid under pressure, means including a control lever to actuate said valve, a pair 01' independent electricalLv controlled valves, one of said valves being connected in a pipe line between the fluid pressure supply and an end chamber at one end or the reversing valve. the other of said valves being connected in asecond pipe line between said supply of fluid under pressure and a chamber at the other end 0! the reversing valve for controlling the shifting of the valve into reverse positions, an adjustable time delay relay which is rendered operative by said control lever, means to render one of said electrically 'controlled valves operative when the control lever is moved in one direction and to render the other control valve operative when the lever is moved in an electrically operated time delay mechanism actuated by and in timed relation with the control lever to open one 01' said valves after a predetermined period of dwell to admit fluid under pressure to the end chamber oi the reversing valve.

6'. In a grinding machine, a longitudinally movable table, means including a piston and cylinder to reciprocate said table, a reversing valve therefor, a supply or fluid under pressure, means including a control lever to actuate said valve to stop the table movement in either direction, a pair oi independent solenoid valves, one of which is connected in a direct pipe line between the supply of fluid under pressure and an end a reversing valve 1 at opposite endsa pair or independent elecreverse positions, an admachine, a longitudinally the'opposite direction, and

the other end of the reversing valve to control the shitting oi the reversing valve into its reverse position, an adjustable time .delay relay which is rendered operative by the shifting of said control lever, said time relay being operatively connected to open one oi said solenoid valves alter a predetermined time interval to pass fluid directly from the supply of fluid under pressure into the end chamber oi the reversing valve rapidly to shift it into the reverse position, and means including a switch actuated by the reversing lever to render one oi the solenoid valves operative when the lever is moved in one direction and-to render the other solenoid valve operative when the lever is moved in the opposite direction.

7. Ina grindina machine, a'longitudinally reciprocable table, means including a piston and cylinder operatively connected to reciprocate said table, a reversing valve which is arranged to admit fluid under preg ure to either end of said cylinder, a pair oi adjustable dogs on said table, means including a control lever operativelycontocutoiiniudunderpressuretobothendsoithe' table and thereby stop the table movement when acted upon byoneoisaiddogs,apairoiindependent solenoid valves operatively connected with an end chamber at each and of the reversing valve, each oi said solenoid valves being connected by pipes directly with the supply of fluid under pressure, a limit switch. so adlustable connection between said lever and a limit switch, and an electrical time delay relay which is set in motion by said limit switch, said time delay relay being operatively connected to enersise one oi said solenoid valves to open the pipe line to pass fluid under pressure directly from themppiyoifluidunderpressuretoanend chamber 0! the reversing valve rapidly to shift the valve into its reverse position.

9. In a grinding machine, a longitudinally reciprocable table, means including a piston andv cylinder operatively" connected to reciprocate said table. a supply of fluid under pressure, a

reversing valve which is arranged to admit fluid nected to move said valve to a central or neutral position when acted upon by one of said dogs to stop the table movement, a pair oi. independent solenoid valves operatively connected with an end chamber-at each end of the reversing valve, said solenoid valves being connected in a direct pipe line irom the supply of fluid under pressure to the end chambers at respective ends of the reversing valve, said solenoid valves serving to control the admission of fluid under pressure to the end chambers alter a predetermined time interval has elapsed, and means includinga time delay relay which is set in motion in timed relaidon with the movement of the reverse lever to open the solenoid valve and rapidly admit fluid under pressure to complete the reverse movement 7 of said valve.

under pressure to either end of said cylinder, a pair of adjustable dogs on said table, means including a control lever operatively connected to move said valve to a central or neutral position to cut on fluid under pressure to both ends or the table and thereby stop the table movement when acted up n by one of said dogs, a pair 0! independent solenoid valves operatively connected with an end chamber at each end 01 the reversing valve, each of said solenoid valves beingconnectedbypipesdirectlywiththesupplyoi fluid under pressure, a limit switch, an adiustable connection between said lever and a limit switch, an electrical time delay relay which is set in motion by said limit switch, said time delay relay being operatively connected to energize one oi said solenoid valves to open the pipe line to pass fluid under pressure directly from the supply of fluid under pressure to an end chamber 01 the reversing valve rapidly to shift the valve into its reverse position, and means including a second switch actuated by the control lever at the ends or its stroke to deenergise the solenoid and break the circuit to allow the relay to reset itself for thenext operation.

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