US2080976A - Hydraulically operated surface grinding machine - Google Patents

Description

W. H. WOOD May 18, 1937.

HYDRAULICALLY OPERATED SURFACEGRIN'DING MACHINE.

FiledJul y 1, 1935 5 Sheets-Sheet i May 18, 1937. w. H. wooo 2,080,976

HY DR AUL ICALLY OPERATED SURFACE GRINDING MACHINE WITNESSES WALLACE H. WOOD 3M6. I n L m W. H. WOOD .May 18, 1937.

HYDRAULICALLY OPERATED SURFACE GRINDING MACHINE Filed July 1, 1935 5 Sheets-Sheet 3 WITNESSES WALLACE H. W001:

W. H. WOOD,

May 18, 1937.

2,080,976 HYDRAULICALLY OPERATED SURFACE GRINDING MACHINE Filed July 1, 1955 5 Sheets-Sheet '4 I40 I43 WALLACE H. W001? Q) I a 3% hflxkn M WITNESSES May 18, 1937. w. H. WOOD HYDRAULICALLY OPERATED SURFACE GRINDING MACHINE s Sheets-Sheet s Filed July 1, 1935 JMJM'M WALLACE H. W002 WITNESSES J/mui-m. A

Patented May 18, 1937 UNll'ED STATES HYDRAULICALLY OPERATED SURFACE' GRINDING MACHINE Wallace H. Wood, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application July 1, 1935, Serial No. 29,225

10 Claims.

,This invention relates to grinding machines, and more particularly to a hydraulically operated surface grinding machine.

In the grinding of plane surfaces, it has been standard practice to use the peripheral face of a grinding wheel and to provide a reciprocating work table opposite the peripheral face of the grinding wheel to support the work piece to be ground. Either the table or the wheel is mounted so that the work and wheel may be fed relatively toward or from each other to grind the work piece to the desired thickness. Such machines have also included a transverse feeding mechanism, so that the grinding wheel and the work may be fed transversely relative to each other so that a work piece surface of greater width than the operative face of the grinding wheel maybe accurately ground to a plane surface. These machines have required the constant attention of the operator to control the transverse and vertical feeding movement so that the wheel and work may traverse transversely relative to each other to grind across the face of a wide piece of work. The prior patent to Whittles No. 1,978,181 improved tire standard practice in surface grinding machines, in that it provided an automatic and self-reversing transverse feeding mechanism which served to automatically traverse the wheel and work transversely relative to each other so that the wheel is indexed intermittently at the end of the table stroke by successive increments until the wheel has ground the entire work face and then automatically reversed so that the wheel and work are fed by intermittent increments in the reverse direction. This automatically reversible transverse feed continues until the operator stops the transverse feed.

It is one of the objects of this invention to provide a hydraulically controlled surface grinding It is still another object of this invention to provide a surface grinding machine with a hydraulic table reciprocating .mechanism which is interconnected with a hydraulically actuated wheel feeding mechanism and serves to feed the work ment at the end of the table stroke to render the table reversing mechanism inoperative and allow the table to move beyond its normal stroke to an inoperative loading position and then stop in a loading position.

It is another object of this invention to provide a fluid pressure table reciprocating mechanism which is provided with a double end piston rod having readily detachable connections between the opposite ends of said piston rod and the adjacent ends of the work table.

Other objects will be apparent from the foregoing description.

One form of this invention has been illustrated in the accompanying drawings in which like reference numerals indicate like parts:

Fig. 1 is a perspective view of the improved grinding machine, having parts broken away and shown in section to more clearly show the operating mechanism;

Fig. 2 is a fragmentary plan view, on an enlarged scale, of the hydraulic piston and cylinder and the cross feed mechanism;

Fig. 3 is a fragmentary front elevation of the cross feed mechanism, having parts broken away and shown in sectioni Fig. 4 is a fragmentary cross-sectional view through the table operating mechanism, showing the cylinder and the control valve in section Fig. 9 is a fragmentary view of the reverse lever and transverse feed control valve similar to that shown in Fig. '7, but with the parts in a different position;

Fig. 10 is a piping diagram of the fluid pressure operating mechanism; and

Fig. 11 is a horizontal sectional view, taken approximately on the line |l--H of Fig. 3.

As illustrated in the drawings, the machine embodying this invention comprises a base I0 which supports a vertically movable wheel slide ll adapted to slide in the vertical slideways l2 and 13. The wheel slide ll carries a horizontally positioned wheel spindle I4 journalled in suitable bearings l5 and I6 on the slide II. The wheel slide II is adapted to be raised or lowered to feed the grinding wheel relatively toward and from the work surface by means of a feeding mechanism comprising a screw 18 which meshes with a nut l9 formed as an integral part of the base In or fixedly mounted thereto. The feed screw I8 is rotatably supported in bearing 20 and carries at its upper end a bevel gear 2| meshing with a bevel gear 22 on a horizontal shaft 23 which is also journalled in a projection of the wheel slide II. The shaft 23 carries a manually operable feed wheel 24 which may be rotated in either direction, depending upon whether it is desired to raise or lower the position of the grinding wheel.

Transversely movable carriage A transversely movable carriage 28 is arranged to slide transversely relative to the base Ill. The carriage is provided with a pair of spaced flat ways 29 and 30 which mate with corresponding flat ways on the base In. A. suitable transverse guide gibbed slideway 3| is provided which is parallel to the ways 29 and 30 and midway therebetween to serve as a guiding means to guide the carriage 28 transversely relative to the base "I.

Longitudinally movable table A longitudinally movable work supporting table 33 is supported on the usual V-way 34 and flat way 35 for a longitudinal reciprocating movement relative to the carriage 28. A work piece 36 may be held on the upper surface of the table 33 while its upper plane surface is ground to the desired extent.

In this type of machine, as illustrated, the grinding wheel is arranged to move in a vertical direction toward and from the work, and the work supporting table is arranged to be moved longitudinally and traversed transversely in order that the entire plane surface of a work piece may be ground to the required extent.

Hydraulic system the piston rod 44 is connected to brackets 41 and-- 48 depending from the longitudinally movable table 33. In the preferred construction, the piston rod 44 is detachably connected to the table brackets 41 and 48 so that the fluid pressure system may be readily disconnected from the table, if desired, when it is desired to traverse or reciprocate the machine manually. In the preslideway 52 (Figs. 1 and 2) and having a vertically movable slide 53 and 54 which is arranged to straddle the piston rod 44 and connect the piston rod 44 to the table 33 when the slide is in a downward position. When it is desired to disconnect the fluid pressure piston and cylinder from the table to permit manual operation thereof, slides 53 and 54 are raised so as to allow the table to slide longitudinally without carrying the piston rod 44 therewith.

The base I0 is formed as a hollow box-like construction in which the lower portion serves as a reservoir 53 for the fluid pressure system. Fluid is drawn from the reservoir 53 through a pipe 54 by a pump 55 and is forced through a pipe 56 to a table control valve 51. A relief valve 58 is provided in the pipe line 56 and is arranged to allow fluid under pressure to by-pass through a pipe 59 and return to the reservoir 53 in case the pressure within the fluid pressure system increases above a desired and predetermined pressure.

The control valve in this application is identical with the control valve shown and described in the copending application Serial No. 141,119 filed August 23, 1934. The control valve 51 combines the functions of a reversing valve and a pilot valve. A reversing lever actuated by the table movement serves to move the valve to a center position and then the fluid under pressure serves to move the reverse or control valve in a reverse direction, producing a smooth reversal of the table movement without the necessity of providing a complicated series of actuating mechanisms and pipe connections. In the form illustrated, a piston type valve (Figs. 1 and 5) is provided including a movable valve member 65 having a plurality of pistons 66, 61, 68, 69 and 10 integrally formed thereon. Fluid under pressure is forced through a pipe 56 into a'pipe (Fig. 10) and chamber 1| (Fig. 5) within the valve casing 51. Assuming the valve is not in a central or neutral position (Fig. 10), fluid under and 15 are formed between the valve pistons 61 and 68, 68 and 69 respectively.

When the valve stem 65 is moved in either direction from the neutral position illustrated in Fig. 5, fluid' under pressure passes either from the valve chambers 14 or 15 through port 16 or 11 respectively, then through pipe 18 or 19 respectively, through cylinder head 45 or 46, into cylinder chamber or 8| to move piston 43 and traverse the table longitudinally.

When valve stem 65 is moved in either direction from the position illustrated in Fig. 5, fluid under pressure may pass from valve chamber 14 or 15 through port 12 or 13, through'port 81 or 88 respectively, into valve chamber 89 or 90. The valve chambers 89 and 90 are formed between valve pistons 66 and 61, 69 and 10 respectively. Fluid under pressure passes from chambers 89 or 90, through port 94 or 95, into a small reservoir 96 or 91. The overflow from reservoirs 96 and 91 is returned to the main reservoir or sump 53 in the base 10.

The effective. areas of valve pistons 66 and 10 is considerably less than the effective areas of valve pistons 61 and 69 respectively. By providing the differential in pressure areas between these valve pistons, the valve chambers 09 and 90 serve to function as a pilot valve and cause a reversal of the reversing valve under the influence of fluid pressure whenever the valve is moved to a position slightly by the center position, as shown in Fig. 5; that is,- so that either the port 81 or the port 88 is cut oil to a greater extent than the other, allowing fluid under pressure to flow into either chamber 89 or 00. Due to the difierential piston areas, the fluid under pressure entering chambers 89 or 90 serves to move the valve piston 66 either towards the right or towards the left, as viewed in Fig. 5.

Speed control valve A speed control or throttle valve I00, as illustrated in Figs. 1 and 5, is formed integrally with the valve 51. As illustrated diagrammatically in Figs. 1 and 10, the valve I00 is shown as a separate valve unit. The valve I00 is preferably located in the-exhaust side of the system so as to maintain a uniform pressure on the operative side of the table operating piston 43. This valve comprises a valve stem IOI which is provided with valve pistons I02 and I03. The valve piston I03 is provided with a V-shaped notch I04 which is located at one end of a pipe or passage I05. The fluid passes from either of the valve chambers I4 and I5 through the V-port I04, throttle valve I00, and exhausts through a passage or outlet pipe I06 into the reservoir 53 a in the base I0.

The throttle valve is arranged so that it may be moved longitudinally from a full line position (Figs. 1 and 4)' to a dotted line position. The valve is provided with an actuating knob IIO on the front end of the valve stem IOI, which permits the valve to be rotated. In the preferred construction, the valve piston I03 is provided' with a V-shaped notch which serves as a V-port to throttle fluid passing therethrough. It is possible to obtain a fine adjustment by cutting off more or less of the V-port to precisely regulate the exhaust of fluid from the system and thereby permit a flne regulation of the table speed. 7

In order that the valve piston I03 may be maintained in the desired adjusted position so as to enable the table to be stopped and started as desired without changing the speed adjustment, a serrated or notched portion H3 is provided and a spring pressed pawl III is carried by the valve casing I00, so that when the knob H0 is turned to adjust the valve piston I03 to give the desired table speed, the pawl I engaging notches in the portion II3 serves to hold the piston in its adjusted position, so as to permit moving the valve stem MI by means of a control lever II5 to start and stop the table movement without upsetting the adjustment of the valve. The control lever H5 is fixedly mounted on the upper end of a rock shaft H6. The lower end of the rock shaft is provided with a yoked member III which engages a groove H0 in knob IIO. An adjustable dog IIO on the table serves to engage a projection I20 on lever H5 and automatically shift the throttle valve to a closed position to stop the table movement when it has been moved to an inoperative or loading position.

In the preferred construction, a yieldable connection, such as a spring H2, is provided between the yoked member II! and rod II 6. The parts are so arranged that when do: II9 en gages lever N5, the valve I00 will be positively moved to a closed position. I The spring II2 serves to allow the knob I I0 to be moved inwardly to open the throttle valve and start the table when the lever H5 is in engagement with the dog I 39.

Fluid by-pass when the throttle valve I00 is in a closed position, stopping the table movement, it is desirable to provide a suitable fluid by-pass wherebyfluid may readily pass from one end or the cylinder to the other to facilitate manual movement of the table. In the preferred construction, a passage or pipe I22 is provided to connect the pipe I9 and valve chamber I5 with a passage or pipe I23 provided as an extension of the pipe I8, so that when the throttle valve. I00 is In a closed. position, as indicated in broken lines in Fig. 10, fluid may readily pass from cylinder chamber 80, through pipe I6, pipe I23, through a valve chamber I26, between the valve pistons I02 and I03, and out through pipe I22, pipe I3,

into cylinder chamber 0|. This by-pass in the throttle valve interconnects the cylinder chambers and III so that when the fluid pressure system is shut off by closing the throttle and control valve I00, the table 33 may then be moved manually, if desired, without being retarded by fluid pressure within the system.

In order to relieve the pressure from reversing valve 51 when the throttle valve is in a closed position, a second by-pass is provided including a chamber or pipe I2I which connects with fluid pressure pipe 56 so as to allow fluid to by-pass from pipe 56 through pipe I2I, valve chamber I25, and to exhaust through a passage or exhaust pipe I06 into the reservoir 53. By providing this latter -by-pass, fluid pressure is relieved from the reversing valve so as to enable the operator to readily shift the reversing valve without moving the valve against the fluid pressure from the pump.

Manual traverse by means of the fluid pressure piston and cylinder, the shaft is moved outwardly toward the operator with the hand wheel I26 in the full line position as indicated in Fig. 4. In this position, the gear I2! is out of-mesh with rack I26 so that the hand wheel I26 remains stationary during the power reciprocation of the work table 33. 'When it is desired to traverse the table 33 manually, the operator moves the hand wheel I26 (Fig. .4) into the broken line position I26a which serves to move the gear I21 into position I2Ia (Fig. 6) in mesh with the rack I28, so that when the wheel I26 is rotated, a traversing movement of the table will be obtained.

Transverse work feed The transversely movable carriage 28 is arranged for a transverse movement relative to the base I0 and the grindng wheel. This may be accomplished by means of a rotatable screw I30 which is supported inbearings I3I and I32 on the carriage 28. The screw I30 meshes with a nut I33 which is fixedly mounted on the base I0. It will be readily apparent from this disclosure that upon rotation of a hand wheel I34 on the outer end of the screw I30, the carriage 28 may be moved transversely to change the position of the work piece relative to the grinding wheel. The transverse feeding movement of the work support is essential in a machine of the surface grinder type" inasmuch as it is frequently necessary to grind a plane surface which is of greater width than the width of the grinding wheel. The work table and wheel are reciprocated longitudinally relative to each other and a relative transverse movement is provided so that on successive relative reciprocations betwen the work and wheel, a relative transverse movement may be obtained so that the wheel operates on a different portion of the work, so that the entire surface of the work may be accurately ground to a plane surface.

Automatic reversal-work table A suitable reversing mechanism is provided to change the direction of movement of the table 33 as desired. In the preferred construction, adjustable dogs I and HI are adjustably .mounted in a T-slot I42 on the table 33. The

a minimum amount of vibration, it is desirable to provide a lost motion connection between the reversing lever and the reversing valve, so that during the initial movement of the reversing lever under the influence of the table dogs, the valve is not moved. This mechanism preferably comprises a relatively short lever I45 mounted on the lower end of sleeve I44. A pivotally mounted plate or lever I46 is supported on a stud I41 on carriage 28. The lever I46 is provided with a pin I48 engaging a groove I49 on the reverse valve stem 65. A suitable yieldable connection is provided between the levers I45 and I46 which com- I prises a link I50 pivotally connected by a stud I5I with lever I46. The link I50 slidably supports a second link I52 which is pivotally connected to lever I45 by means of a stud I53. A spring I54 is interposed between projections, of the links I 50 and I52 so that when the reverse .lever I43 is moved in either direction by means" of the dogs I40 and I, the spring serves to take up the initial movement so that the movement of the reversing valve may be picked up without a sudden shock or vibration being transmitted thereto. It will be readily apparent from of the carriage 28 to cause a transverse movement the foregoing disclosure that when the throttle valve is moved tostart the table movement, the table 33 will reciprocate under the influence of fluid under pressure within the cylinder 40, and the length of the reciprocatory stroke will be governed by the position of adjustable dogs I40 The dogs engaging the reversing lever I43 serve to shift the reversing valve member 65 so as to automatically change the direction of movement of table 33, as desired.

Power operated wheel feeding mechanism It is desirable to provide a suitable power actuated means for causing a transverse movement of the work piece relative to the grinding wheel, so that the grinding wheel will'grind a different path across the face of the work at each reciprotudinally movable work table.

As illustrated in the drawings, a forward and reverse feed are obtained by the gear mechanism, as illustrated in Figs. 2 and 3, comprising gears I58 and I59 mounted on the outer end of the feed screw I30. The gears I58 and I59 are mounted on a slidable sleeve I60 which is slidably keyed to the feed screw I30. The sleeve I60 may be moved axially by a reversing lever I6I having a yoked-portion engaging a groove in the outer periphery of the sleeve I60. In the position of parts illustrated in Fig. 2, lever I6I is in the forward position, meshing the gear I59 with an idler gear I62 which also meshes with a driving gear I63 mounted on a shaft I64, to cause a transverse movement of the slide 28 towards the front of the machine. If it is desired to move the carriage away from the front of the machine or in the reverse direction, the operator shifts the lever I6I from the full line position as indicated in Fig. 2 into the dotted line position I6Ia which serves to slide the sleeve I60 downwardly (Fig. 2) so that the gear I58 meshes directly with the driving gear I 63. If it is desired to cause a manual transverse feeding movement, the lever I 6I is moved into a central or neutral position, as indicated by dotted position I6Ib, which serves to slide the sleeve I60, disengaging both gears I58 and I59 so as to allow free rotation of the feed screw without turning the gear mechanism.

In order to rotate the driven gear I63, a fluid pressure cylinder I66 is provided on the carriage 28. This cylinder I66 contains a piston I61 which has a rack formed on its outer end. The rack I 68 meshes with a pinion I69. The pinion I 69 is connected to a pawl-carrying lever I10 having a pawl I1I engaging a ratchet wheel I12 which is fixedly connected with the driving gear I63. It will be readily apparent that when ,fluid is admitted to a cylinder chamber I13, it serves to move the piston towards the left, as viewed in Fig. 2, against the tension of a spring I14, to move the rack I68, causing the pinion I69 to rotate in a counterclockwise direction carrying the pawl !1I which in turn rotates the ratchet wheel I12, gear I63, and serves to rotate the feed screw I30 in either direction, depending upon whether the gear I58 or gear I59 is in operative mesh.

In order to regulate the extent of movement comprises an adjustable stop screw I16 which is arranged in the path of the rack I68 to limit its motion, as caused by fluid under pressure, and thereby restrict and limit the movement of the feed pawl. The spring I14 serves to return the rack, piston and pawl to an inoperative position after the pressurehas been relieved within the cylinder chamber I13.

In order that the transverse carriage feed may be actuated in timed relation with the table reciprocation so that the transverse feed takes place at the end ofthe table stroke, it is desirable to provide a suitable control valve which is actuated in timed relation with the table reversing mechanism so that the feeding mechanism may operate in the desired and timed relation with the table movement. As illustrated in the drawings, a controlvalve I89 is provided having a piston IN. The valve piston I8I is preferably arranged so that it may be actuated in timed relation with the reversing lever I48. In the preferred construction, a cam I82 which is moved by or in timed relation with the lever I83 serves to engage a roller I83 mounted on the end of the valve piston I8I so .that the valve pistons may be moved when the reversing lever is shifted. In the position illustrated in Fig. 9, fluid is conveyed to the control valve through a pipe I84 into a valve chamber I85 and in the position of the valve, as illustrated in Fig. 9, out through a port I86 and a pipe I81 to the feed cylinder chamber I13. when the valve piston I8I moves into a position, such as that shown in Fig. 7, the fluid under pressure may exhaust from feed cylinder I18 through pipe or passage I" through port I86, valve chamber I89, port I88 and pipe I9I to, return to the reservoir within the base of the machine. A spring I92 within the valve piston I8I serves to hold the piston in a direction toward the left, tending to hold the piston up against a stop plate I93, which limits its movement towards the left.

In grinding various pieces of work, it is desirable to at times provide a transverse feeding movement of the work table relative to'the wheel at each end of the table reciprocation or in other types of grinding, it may be desirable to feed at only one end of the table stroke, depending upon the surface being ground and the nature of the work and the finish desired.

A feed control mechanism is provided which is arranged to actuate the valve piston I8I at both ends of the table stroke or at either end of the table stroke. In the preferred construction, this is accomplished by means of the cam I82 which is carried by the lever I48. The cam I82 is provided with three surfaces, namely, a surface I94 which in an operative position serves to cause a transverse feeding movement of the carriage 28 at each end of the reciprocatory stroke of the longitudinally movable table 88. A cam surface. I95 on the Figs. 1 and 3. The cam I82 is provided with a further cam surface-I98 which serves when in an operative position to cause a transverse feeding movement of the can'iage 28 when the longitudinally movable table is at the right-hand end of its reciprocatory stroke.

A suitable adjusting means is provided to regulate and control the position of cam I82. so as to move cam surfaces I94, I95 or I96 into an operative position relative to the valve roller I83. As Illustrated in the drawings, this adjusting mechanism may comprise a manually operable handle I81 which is fixedly mounted on the collar I98 on the upper end of a sleeve I99 which is in turn rotatably mounted in an aperture 298 in the carriage 28. The lower end of the sleeve I99 is provided with a gear segment 2IlI which meshes with a gear 282 which is fixed to cam I82. The cam I82 and gear segment 282 are rotatably mounted on a stud 883 fixedly mounted on a lever I45 carryin the stud 288, gear 282 and cam I82 and which is keyed to a. sleeve I which is formed to turn with the reversinglever it when the same is actuated by the table reversing dogs I48 and I. In order that the cam I82 may be located in any one of three positions relative to the reversing lever so as to cause a transverse feeding movement of the carriage 28 either at both ends of the table stroke or at either end of the table stroke, a spring-pressed ball 206 is provided on the enlarged head 28'! of sleeve I48. The ball 288 is adapted to be located in any one of three depressions or recesses in collar I98, in a recess 298, 299 or 2 I8, depending upon the transverse feed desired. By swinging the control lever I91, the collar I98 and sleeve I99 may be rotated to shift the position of the cam I82 and may be located in one of three positions by the spring pressed ball 286 cooperating with the recesses 288, 299 and 2H! to swing cam face I94, I95 or I96 into operative position relative to the valve actuating roller I83, thus permitting a readily accessi- .ble means for obtaining the desired transverse feeding movement of the carriage 28.

Table loading position It is desirable to provide a suitable means for readily positioning the longitudinally movable table 33 in an inoperative or loading position which, as illustrated, may be when the table 33 is in its extreme right-hand position, as viewed in Fig. \l. In order that the table may be moved to such a position. it is desirable to provide a readily accessible means for rendering the dogs or reversing lever I43 ineflective so as to allow the table 88 to travel to a position beyond its normal reciprocatory stroke. As illustrated in the drawings, this may be accomplished by pivotally mounting the lever I48 on a horizontally positioned pin or stud 2I2 which permits the lever I43 to be rocked in a vertical plane so that when desired a manually operable lever 2I3 projecting 9 I48 which permit the table 83 to travel beyond its normal reciprocatory stroke toward the right.

As illustrated in the drawings, when lever 2I3 is raised to its inoperative position 2I3a, to allow the table to travel to a loading position, this idle stroke of the table is continued until the dog II9 engages the projection I28 of lever I I5 and shifts the throttle valve IN to a closed position to stop the table movement at the end of its idle stroke. By adjusting the position of the dog I I9, the table may be stopped in any desired position beyond the normal reciprocatory stroke of the table.

Automatic table stop It is desirable to provide a suitable means for automatically'stopping the transverse movement of the carriage 28 after it has traversed trans versely through a predetermined extent, so that the grinding wheel has ground the entire surface of the work to be ground, and to automatically run the table to an inoperative or loading position. This is preferably accomplished by an adjustable dog mechanism comprising the adjustably mounted dogs 2E8 and 2I8 which are adjustably supported in a T-slot 2I'I on base I9. The dogs 2I8 and 2I8 are adapted to be engaged by a v-shaped projection 2I8 on a rock arm 2I9 which is fixedly connected to a rock shaft 229. A lever MI is mounted on the other end of the rock shaft 228 and is arranged to engage the lower end of a rod 222 which is slidably mounted within the sleeve I84. The upper end of rod 222 engages a' pin 223 on the reversing lever I43". The rock arm 2I9, rock shaft 229, lever 22I and rod 222 are all carried by the carriage 28. As the carriage 28 is moved transversely during grinding, the v-projection 2H8 will engage. either the adjustable dog 2|! or 2I8 after a predetermined transverse movement. When the V-shaped projection 218 rides up on either of the dogs 215 or 216, as illustrated in broken lines in Fig. 6, the rock arm 219 will be rocked in a counterclockwise direction, also rocking the rock shaft'220 and lever 221 in a counterclockwise direction to raise the rod 222. The rod 222 butting against the pin 223 serves to rock the reverse lever 143 in a clockwise direction into position 213a, which serves to depress the operative end of reversing lever 143 so that dog 140 will pass over the lever and the table 33 will automatically move toward the right to an inoperative or loading position. By adjusting the position of dogs 215 and 216, the automatic transverse movement of the work supporting carriage 28 may be varied according to the surface of the work piece which it is desired to grind.

The shaft 221) is resiliently held in an operating position with the lever 219 in the path of the dogs 215 and 216 by means of a spring 214. When it is desired to start the table reciprocation, the shaft 220 is moved toward the right (Figs. 1 and 3), against the tension of spring 214, a sufficient distance to move lever 219 out of the path of the dogs 215 and 216. This movement allows the reverse lever 213 to move from position 213a into an operative position with projection 143 in the path of dogs 140 and 141.

The operation of this machine will be readily apparent from the foregoing disclosure. The oper tor places the work pieces 36 to be ground on the table 33, adjusts the position of dogs I19, 140, 141, 215 and 216. The motor is then started to rotate the grinding wheel and the longitudinal reciprocation of the table 33 is started by the shifting of the lever 218 out of the path of the dogs 215 and 216, then pulling out on the throttle valve and stop control valve knob 11!] and shifting the reverse lever 213 into a reverse position. This serves to allow fiuid under pressure to ex haust from the inactive side of the piston 43 and thereby cause the table to start its grinding stroke. By proper adjustment of the dogs above mentioned, the table 33 and carriage 28 may be moved longitudinally and transversely to grind the surface of the work to the required extent. By adjustment of the lever 191, the cam 132 may be positioned so that a transverse feeding movement of the carriage 28 may be caused at either or both ends of the longitudinally movable table stroke.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A grinding machine comprising a base, a rotatable grinding wheel, a vertically movable slide to support said wheel slide, a transversely movable carriage on said base, a longitudinally reciprocable work table on said carriage, means to feed the wheel slide toward and from the work table, means including a hydraulically actuated pawl and ratchet mechanism to cause a transverse feeding movement of said carriage, means including a piston and cylinder operatively connected between said carriage and table to reciprocate the table longitudinally, means including a lever and reverse valve to automatically change the direction of movement of said table, and a fluid pressure mechanism independent of said fluid pressure table reciprocating mechanism including a control valve actuated in timed relation with the reverse lever to actuate said pawl and ratchet mechanism at either or both ends of the table stroke to cause a transverse feeding movement of the carriage.

2. A surface grinding machine comprising a base, a rotatable grinding wheel, a vertically movable slide supporting said wheel, a feeding mechanism to adjust the slide vertically relative to the base, a longitudinally movable work supporting table, a transversely movable carriage which supports said longitudinally movable table, a piston and cylinder mechanism interposed-between .the transverse slide and the table to cause a reciprocation of the work table, means including-a reversing valve actuated by movement of the table to cause a reversal in direction of the table movement after it has traversed to a predetermined position, a feeding mechanism operatively connected to cause a transverse movement of said slide and table, means actuated by and in timed relation with the table reciprocation to cause said feeding movement at the end of the table stroke, and automatically actuated means to terminate said transverse feed and the longitudinal feed when the wheel and the work have been moved relatively in a transverse direction, stopping the work table in its right-hand end or loading position.

3. A grinding machine comprising a base, a rotatable grinding wheel, a vertically movable slide for said wheel, a transversely movable carriage mounted on said base, a longitudinally movable work supporting table on said carriage, means to feed said wheel slide vertically to adjust the position of the wheel relatively toward and from the work, means including a reversing mechanism to reciprocate said table, a reversing lever and adjustable dogs interposed between the carriage and table to actuate said reversing mechanism, means including a feeding mechanism to cause a transverse movement of the carriage and table relative to the grinding wheel to feed the work transversely, and means including adjustable dogs on said base which serve to render said longitudinally movable table reversing mechanism inoperative after the carriage has moved transversely to a predetermined extent to stop the longitudinal movement of the table after a predetermined grinding operation.

4. A grinding machine comprising a base, a rotatable grinding wheel, a vertically movable slide on said base to support said wheel, a transversely movable carriage on said base, a longitudinally movable work table on said carriage, a reversing mechanism interposed between the carriage and table to reciprocate said table longitudinally, means including a reversing lever and adjustable dogs to actuate said reversing mechanism, means to cause a transverse feeding movement of said carriage to move the work piece transversely relative to the grinding wheel, means including adjustable dogs on said base and a lever mechanism to render said table reversing lever inoperative after the carriage has been moved transversely to a predetermined extent to allow the table to move to and stop at a loading position beyond the normal reciprocatory stroke.

5. A grinding machine comprising a base, a rotatable grinding wheel, a vertically movable wheel slide to support said wheel, a transversely movable carriage on said base, a longitudinally movable work table on said carriage, means to move the wheel slide vertically to cause said wheel feeding movement of said-carriage to move the work table transversely relative to the grinding wheel, means including a piston and cylinder interposed between the carriage and Work table to reciprocate said table, means including a reverse lever and valve to reverse the direction of movement of said table, adjustable dogs on said table to actuate said reversing mechanism, and means including adjustable dogs on said base which serve to render said table reversing dogs inefiectivc after the carriage has moved transversely to a predetermined extent toallow the table to traverse by the normal reciprocatory stroke and to stop in a predetermined loading position.

6. A grinding machine comprising a base, a vertically movable slide, a rotatable grinding wheel, a transversely movable carriage mounted on said base, a longitudinally movable work table, means including a-pawl and ratchet mechanism to cause a transverse feeding movement of said carriage to move the work piece transversely relative to the grinding Wheel at the ends of the table stroke, means including a fluid pressure piston and cylinder operatively connected between the carriage and table to reciprocate said table, a reversing mechanism including a lever and'a valve to change the direction of movement of said table, adjustable dogs on said table arranged to actuate said lever to reverse the table at either or both ends of its stroke ata predetermined position, means including adjustable dogs on said base and a pivotally mounted lever engaged thereby which are arranged to render said reversing lever inoperative after the carriage has moved transversely to a predetermined extent to allow the table to'travel beyond the reversing dogs, and means including a third adjustable dog on said table to stop said longitudinally movable table in a predetermined'loading' position.

'7. A grinding machine comprising a base, a rotatable grinding wheel, a movable wheel slide to support said wheel, a longitudinally movable table, means to move the wheel slide to cause the wheel to move relatively toward and from the work table, means including a piston and cylinder to reciprocate said table, means including a revers ing lever and valve to reverse the direction of movement of the table, adjustable dogs on said table to actuate said reversing lever, a control valve arranged to throttle the flow of fluid to said system, means to rotate said valve to regulate the speed of movement of said table, means to render said reversing lever ineffective to allow the table to move beyond its normal reciprocatory stroke, and means including a third dog on said table to move said control valve endwise to stop the table when it has moved to a predetermined loading position beyond the normal reciproc'atory stroke.

8. A hydraulic grinding machine table recipro cating mechanism comprising a longitudinally movable table, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a reversing valve arranged to reverse the direction of movement of said table, means including a reversing lever and a pair of adjustable dogs on said table to actuate said reversing mechanism, a control valve which serves to regulate the speed of movement of said table, means to render said reversing lever inoperative to allow the table to pass beyond the normal reciprocatory stroke, a third dog on said table, a lever in the path of said'third dog and arranged to move said control valve to a closed position to stop the table movement in a predetermined loading position, and a resilient connection between the lever and control valve which permits the operator to open the control valve so as to start the table reciprocation after a new piece of work has been loaded on the machine.

9. A grinding machine comprising a base, a rotatable grinding wheel, a wheel slide to support said wheel, a longitudinally movable work table, means to move the "wheel slide to cause the wheel to move relatively toward and from the work table, means including a hydraulically actuated pawl and ratchet mechanism to cause a relative transverse feeding movement between the wheel and work, means including a piston and cylinder to reciprocate said'table, means including a reversing'lever and valveto reverse the direction of movement of said table, a. control valve arranged to admit fluid to said hydraulically actuated pawl and ratchet mechanism to cause a transverse fee-ding movement, and an adjustable cam associated with said reverse leverj' 10. A grinding machine comprising'a base, a

rotatable grinding wheel, a wheel slide to support said wheel, a longitudinally movable work table, means to move the wheel slide to cause the wheel to move relatively toward and from the work table, means including a hydraulically actuated pawland ratchet mechanism to cause a relative transverse feeding movement between the wheel and work, means including a piston and cylinder to reciprocate said table, means including a reversing lever and valve to reverse the direction of movement of said table, a control valve arranged to admit fluid to said hydraulically actuated pawl and ratchet mechanism to cause a transverse feeding movement, an adjustable cam associated with said reverse lever for actuating said control valve, which serves to actuate the controlvalve when the reversing lever is shifted at reversal to cause a transverse feeding movement at either or both ends of the work table stroke, and means to adjust the extent of traverse movement between said wheel and work at rcversal.

WALLACE H. WOOD.

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