US2396892A - Hydraulic cylindrical grinding machine - Google Patents

Description

March 19, 1946. H. A. SILVEN I 4 HYDRAULIC CYLINDRICAL GRINDING MACHINE Filed Nov 16, 1.944v 5 Sheets-Sheet 1 HER'BERT A g Elm/EN March 19, 1946.

H. -A-. SILVEN 4 2,396,892

HYDRAULIC CYLINDRICAL GRINDING MACHINE Filed Nov 16, 1944 5 Sheets- Sheet 2 March 19, 1946. H. A. SILVEN 2,395,892 HYDRAULIC CYLINDRICAL GRINDING MACHINE FildNov. 16,1944 5 Sheet'-Sheet 3 137a 1376i 5 I .I 776/170 177 788 I75 I72 I73 "718-5 HERBERT A. SILVEN wmmsagm W I35 :34 IO 5 Sheets-Sheet 4 v HER'E1ER'T A SILVEN March 19,1946. A. SILVEN.

HYDRAULIC CYLINDRICAL GRINDING MACHINE Filed Nov. 16, 1944 LD-Qdtavv. W 9.

arch 19, 194; H. A. $ILVE N 7 HYDRAULIC CYL INDRICAL GRINDIL IG MAC HINE Filed Nov. 16, 1944 5 Sheets-Sheet 5 am I HERBERT A. SILVEN UNITED STATES PATENT OFFICE.

HYDRAULIC CYLINDRICAL GRINDING momma Herbert A. .Silvem Worcester, Mass.,- assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application November 16, 1944, Serial No. 563,683 Claims. (01. 51-95) This invention relates to grinding machines, and more particularly to a hydraulically operated cylindrical grinding machine.

One object of the invention is to provide a simple and thoroughlypractical cylindrical grinding machine. to provide a hydraulically operated cylindrical grinding machine with a main control valve mechanism which is arranged to control the various mechanisms of the machine. Another object of the invention is to provide a hydraulic cylindrical grinding machine with a main control valve which is actuated by and in timed relation with the manually operable feed mechanism so as to control the grinding wheel feed, the work table reciprocation, the disconnection of the manually operable traverse mechanism during hydraulic Another object of the invention is as shown in Fig. 1,. having the manually operable feed wheel removed;

Fig. 4 is a fragmentary cross sectional view, on

an enlarged scale, through the manually operable feeding mechanism, taken approximately on the line 4-4 of Fig. 1;

reciprocation of the work table, and also the stopping and starting'of the work drive motor.

Another object of the'invention is to provide a hydraulically operated feeding mechanism which is operated by and -in timed relation with the shifting of the table reversing valve to cause a predetermined infeeding movement at table reversal. Another object of the invention is to provide an improved table reversing valve, in which an adjustable dwell control valve is pro vided to permit an adjustable but predetermined dwell of the table at reversal in a-traverse grinding operation. Another object of the invention is to provide a hydraulically operated grinding machine with a main control valve which is actuated by manual operation of the feed mechanism to control the shifting .of the feed control valve" ior positioningv the grinding wheel either in an inoperative position or in a grinding position.

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 or parts, as will be exemplified in the structure to be hereinafter described, 'and the scope of the application of which will be indicated in the following claims. 7 One embodiment of the invention has illustrated in the drawings, in which:

Fig. 1 is a front elevation of the improved hydraulically operated cylindrical grinding machine; I I Fig. 2 is a diagrammatic illustration of the hydraulic control mechanism and a simplified elec- Fig. 3 is a fragmentary front elevation,jon an been Fig. 5 is a fragmentary sectional view, on an.

.infeeding mechanism;

Fig. 6 is a fragmentary sectional view, partly in elevation, taken approximately on the line 6-6 of Fig.3; g

Fig. 7 is a fragmentary sectional view, taken approximately on the line 'i-.-'| of Fig. 3, through the load. and fire mechanism for actuating the main control valve; I Fig. 8 is a fragmentary sectional detail view through the latch pin for latching the hydraulically operated feed gear in an operative hand or manual feeding position; a

Fig. 9 is a similar .fragmentary sectional view showing the position of the eccentric latching pin when the parts are in position for an automatic infeeding operation; and.

Fig. 10 is a fragmentary detail view, on an enlarged scale, of the adjusting and stop mechanism for thedwell control valve.

' An improved hydraulically operated cylindrical grinding machine has been illustrated in the drawings comprising a base II! which serves as a support for longitudinally reciprocable work supporting table II. The table It is arranged to be traversed or reciprocated longitudinally on a flat way i2 and a V-way' I3 formed on the upper surface of the base- Ill. -The table Il may be traversed longitudinally by a manually operable hand wheel H through a manual traverse mechanism to be hereinafter described.

A fluid pressure mechanism is provided for "prising a. cylinder 8 5 which is fixed relative to the base Ill. mounted piston is which is fixedly connected to The cylinder l5 contains a'slidably a double end piston rod .l'l. The opposite ends of the piston rod H are connected by depending brackets l8 and is fixedly mounted on the under side-of the table H at its-opposite ends.

A table reversing or control valve 20 is provided ier controlling the admission to and exhausto! trical diagramof'the work driving mechanismrfiuic lfrom-the cylinder l5. When fluid under pressure is passed through a pipe 2| and a pipe or passage 22 into a. cylinder chamber 23, it will cause the piston l6 andjthe table .II to move toward the right (Fig. 1). During the movement of the piston it toward the right, fluid within a cylinder chamber 24 willexhaust through a pipe or passage 25 and through a pipe 28 to the control valve 28.

The work table II serves as a support for a' rotatable work piece 21. The work piece 2'I is supported on a headstockcenter 28 and a footstock center 28 which are in turn supported by I a headstock 38 and a footstock 3|, respectively. The headstock 38 is preferably a motor driven headstock comprising an electric motor 32 which is provided with a driving pulley 33 (Fig. 2) which is connected by multiple V-belts 34 with a pulley 35 to drive the work piece 21 during a grinding operation.-

is fixed relative to the base I8 and its other end is rotatably supportedin a sleeve bearing "which is also fixed relative to the base I8.

The feed wheel I8 is provided with an old and well known micrometer adjusting'mechanism I which is substantially the same as that shown in the expired U. s. Patent No. 762,838 to c. H. Norton dated June 14, 1904, to which reference may be-had for details of disclosure not contained A transversely movable wheel slide 38 is arranged to move transversely relative to the base ID on a V-way 38 and a'flat way 48 (Fig. 1).

The wheel slide 38 is-provided with a rotatable wheel spindle 4| which supports a grinding wheel 42. at its left-hand end. The spindle 4| and grinding wheel 42 are preferably positively driven by any suitable means such as, for example, an electric motor 43 which is mounted on the upper surface of the' wheel slide 38; The motor 43 is provided with an armature shaft 44 which supports a multiple V-groove pulley 45. The pulley 45 is connected by multiple V-belts .46 with a multi-V-groove .pulley 41 which is mounted on the right-hand end of the wheel spindle 4!.

A nut and screw feeding mechanism is provided for feeding the wheel slide 38 transversely relative to the base 18. This mechanism may comprise a rotatable feed screw 58 which meshes with a depending half nut 5i fastened to the under side of the wheel slide 88. A reduced end portion 52 of the feed screw is slidably keyed within a rotatable sleeve 53. The sleeve 53 is Journalled in anti-friction bearings 54 and 55 which are in turn fixed relati'veto the base I8.

' The right-handend of the feed screw 50 is journalled in suitable bearings (not shown) in a slidably mounted sleeve 58 which is slidably keyed within a portion of the base l8.

In order to move the wheel slide 38 rapidly t and from a grinding position, a hydraulically operated mechanism is provided comprising a hydraulic cylinder 51 which contains a 'slidably mounted piston .58. The piston 58 is connected to a double end piston rod 58, the left-hand end of which is fastened to the slidably mounted sleeve 56. As illustrated in Fig. 2, the piston rod 58 is arranged in axial alignment with the axis of the feed screw 58.

A control valve 88 is provided to control the admission to and exhaust of fluid from the cylinder 51. -When fluid under pressure is admitted through a pipe into a cylinder chamber 82, it will cause the piston 58, the feed'screw 58, and

the wheel slide 38 to move to an operative posiported on a reduced cylindrical end portion II of a rotatable shaft I2. ,The shaft 1.2 is rotatably herein. The'micrometer feed adjusting mechanism I5 is provided with a pinion I8 which meshes with a-gear I1. The gear 11 is'pinnedto the shaft I2. A pinion 18 is formed adjacent to the right-hand end of the shaft I2. The pinion I8 meshes with a gear I8 which is rotatably supported on a stud 88. The gear 18 in turn meshes with a gear 8i which is formed integral with the sleeve 58. It will be readily apparent from the foregoing disclosure that a rotary motion of the manually operable feed wheel III will be imparted through the micrometer adjusting mechanism I5 to rotate the gear H which in turn rotates the shaft I2 and through the gear'mechanism above described serves to transmit a rotary motion to the feed screw 58 to transmit atransverse feeding movementthrough the half nut 5| to the wheel slide 38 and the grinding wheel 42.

A power operated feeding mechanism is-provided'for rotating the feed screw 58 intermittently at the ends of the table stroke for a traverse grinding operation. This mechanism is preferably hydraulically operated comprising a rotary vane type fluid motor 85 having a rotatable rotor shaft 86. A rotor 81 is formed integral with the shaft 86 and serves as a support for a single vane '88 (Fig. 2). A fixed plate 88 within the motor 85 serves to limit the rotary motion of the vane 88. When fluid under pressure is admitted through a passage 88 into a cylinder chamber 8i, the rotor 81 and vane 88 will be moved in a counterclockwis'e direction (Fig. 2) to cause an infeeding movement of the grinding wheel 42. During this movement, fluid within a motor chamber 82 i will exhaust through a passage 83.

A control valve 85 is provided for controlling the admission to and exhaust of fluid under pressure to the motor 85. The valve 85 comprises a valve stem 88 having a plurality of valve pistons formed integrally therewith so as to form valve chambers8'l, '88, 88, I88 and "II. When fluid under pressure is passed through a pipe I82 in a manner to be hereinafter described, it will enter the valve chamber 88 and pass through passage 88 into motor chamber 8| to start a counterclockwise rotation of the vane 88 to produce an infeedin'g movement of the grinding wheel. The valve is preferably hydraulically actuated in timed relation with the other mechanisms of the machine. A pipe I83 is connected with the valve chamber I8! and serves to .convey fluid under pressure to move the valve stem88 to its extreme left-handend position (Fig. 2).v Similarly, a pipe I84 is connected at the other end of the valve 85 to admit fluid to or exhaust fluid from the valve chamber. 81 formed at the left-hand end of the valve 85. When fluid under pressure is passed through the pipe I84 into the chamber 81, the

; valve stem 85 will be moved toward the right (Fig; 2). valve stem 81 toward the right, as the valve chamber 88 is' opened to the pressure pipe I02, fluid I under pressure will be passed through the passage 88 into the motor chamber 8| tostarta counterclockwise movement of the vane 88 to During the shifting movement of the aeoasee wheel. This movement continues until the valve chamber 9% "moves out of communication with the passage as and is positioned to pass fluid under pressure from the pipe m2 through the valve chamber as, the passage 93, into the motor chamber 92 to move the vane 88 in a clockwise direction to return the grinding wheel to its initial position. Similarly, at the other end of the table stroke, when fiuid under pressure is passed through the pipe I or into the valve chamber Isl, the valve stem at will be shifted toward the left. During the movement of the valve stem toward the left, fluid under pressure will'first be admitted from the pipe I92 through the valve chamber 99 into the passage 9@ and the motor chamber at to initiate an infeeding movement of the grinding wheel, after which flui will be admitted from the pipe It? through the valve chamber IIJii (Fig. 2), through the passage 95, into the motor chamber 92, to move the vane 88 in a clockwise direction to return it to its initial position. It will thus be seen that during each shifting movement of the valve stem either toward the right or toward the left, the vane 88 will first be moved in a counterclockwise -direction to feed the grinding wheel into the work, after which the vane 88 is moved in a clockwise direction to return the grinding wheel to its initial position.

,The rotor shaft 36 of the motor 85 is provided at its outer end with a gear Ito which is keyed thereto; The gear I III meshes with a gear II I which is mounted on a rotatable sleeve I I2. The sleeve H2 is connected by a one-way ball clutch MS with a rotatable sleeve III; which supports a gear H5. The sleeve H2 is rotatably supported on anti-friction bearings carried by a stud I I6 which is fixedly supported within a casing III.

erable hand wheel 70. The abutment I2 Ia serves as a positive stop to limit the rotary infeeding movement of the hand wheel It. i

The casing III which supports the feed gearing may be moved to an operative position, in

which position a slidably mounted latch stud I23 having a reduced eccentric portion or pin I213 may slide into engagement with an aperture I 25 which is fixed relative to the base of the machine. The engagement of the pin I26 with the hole I25 serves to lock the casing Ill so that the gear H5 will be located either in position II5a or IIEb. The pin IN, which is formed integral with the latch stud- I23,- is preferably eccentrically mounted relative thereto so that in the position illustrated in Figs. 6 and 8, it will position the feeding, gear I is in position lite for a hand feeding operation. If it is desired to provide a power infeeding movement of the grinding wheel, the

latch stud I 23 maybe rotated by means of a knob 25 to shift the position of the eccentric stud I24? so that the casing III? is rocked relative to the aperture I25 so that the driving gear IIii will move into position I I52; in mesh with the gear it. t will be readily apparent from the foregoing disclosure that a'rotary motion, of the vane 88 oi the motor 85 will be transmitted through the gear mechanism above described to rotate the gear Tl,- which movement in turn will be transmitted through the shaft I2 to rotate the feed screw 56 and thus impart an infeeding movement to the grinding wheel d2.

The one-way ball clutch M3 which is located between the sleeves II2and IIi serves to transmit the rotary motion of the vane type motor to rotate the gear I? when the vane is moved in a counterclockwise direction to cause an infeeding movement of the grinding wheel. When the fiuid under pressure is reversed to rotate the vane 88 in a clockwise direction, the ball clutch H3 will slip so that the rotary motion of the gear II I will not be transmitted to cause a rotary motion of the gear IIii so that the vane type motor 85 may be returned to its initial position (Fig. 2) without turning the feed screw.

In order to facilitate setting up the machine, it is. desirable to provide a suitable adjusting mechanism whereby the vane 88 of the fluid motor 85 may be adjusted relative to the casing I II. This is preferably accomplished by providing an adjusting knob I30 which supports a graduated dial I3I. An index or zero marker I32 is pro vided 0n the casing III. A clamp mechanism is provided comprising a bracket I33 having a clamping screw Itfi which is screw threaded into housing Hi. When it is desired to adjust the position of the vane relative to the casing II I, the screw it may be loosened and the knob I30 rotated to the desired extent, after which the screw Its again may be clamped to lock the parts in adjusted position.

A suitable stop mechanism is provided for him iting the swinging movement of the housing III in a counterclockwise direction. This mechanism may comprise a stop pin I35 which is fixed relativeto the base It of the machine. A projecting lug I35 formed on the casing III is positioned to engage the stop pin I35 and thus restrictthe counterclockwise swinging movement of tion (Figs. 1 and 3) to throw the gear 'I I5 into an operative position. When it is desired to disconnect the power feed gear from an operative position, the lever I31 may be swung in a counterclockwise direction (Fig. 6) to withdraw the latch pin I23. that is, to move it toward the right (Fig. 6) to withdraw the eccentric end portion I2 3 out of engagement with the locating hole I25 and the released tension of a spring Mil will shift the housing i It to an inoperative position with the gear H5 in the full line position as indicated in -Fig. 3. The spring I it is connected between a or a left-hand end position (Fig. 2) by means of shaft 110.

' support for a pair of pivotally mounted members aligned with the pin I50, the valve stem I45 may be moved longitudinally, as desired. Kit is desired to latch the valve in either a right-hand or a left-hand end position (Fig 2), the valve stem I45 is moved into the desired position and the knob I49 rotated so that the pin I50 engages either the groove I5I or the groove I52 to lock the valve stem I45 so that the wheel slide 39 will be maintained either in a forward operative position or in a rearward inoperative position.

In the position of the valve so as shown in Fig. 2, mild under pressure passing through a pipe I54 enters a valve'chamber I56 located between the valve pistons I66 and It? and passes out through the pipe 66 into the cylinder chamber 63 to move the piston 58 and wheel slide 38 into a rearward or inoperative position. During this movement of the piston 58, fluid within the cylinder chamber 62 exhausts through the pipe BI into a valve chamber I56 located between the valve pistons I41 and I48 and passes out through a pipe I51 into a reservoir I53.

It is desirable that the wheel feeding mechanism be arranged so as to initiate a. grinding cycle, that is, so that when a work piece 21 has been mounted in position on themachine, the operator is merely required to turn the feed wheel to start a forward feeding movement of the grinding wheel 42, to start a reciprocatory movement of the work supporting table II and to start pair of opposed studs I66 (Fig. 4) with a rockarm I69. The rock arm I69 is fixedl mounted on a rock shaft I10.

A load and fire mechanism is supported on the forward end of the rock shaft I10 and comprises a flanged member I1I which is pinned to the rock The flanged member III serves as a I12 and I13 each of which is arranged to engage a stud I14 which is fixedly mounted on the flanged member IN. The members I12 and I13 are normally maintained in engagement with the stud I14 by means of a tension spring I15 which is connected by the studs I16 and I11 which are fixedly mounted on the members I12 and I13, re-

spectively. The upper ends of the members I12 and I13 are provided with cam faces I19 and I19 which are staggered or oifset relative to each other and are arranged to be engaged by a pair.

hand wheel 10 and engages a nut I85 which is slidably'mountedin a T-shaped arcuate groove I86 extending around the collar I83 (Figs. 3 and It will be readily apparent from the foregoing disclosure that when the hand wheel I10 is ro= tated, either the cam I or the cam IBI will engage the cam faces I18 or I19 respectively to rock either the member I12 or the member I13 and through the pin I15 to rock the shaft I10 and thereby shift the valve stem I6I to shift the position of the-main control valve IEO so as to start or stop a grinding operation, as desired. A spring-pressed detent I81, which is fixedly mounted relative to the base I0, is arranged in the path of an arrow-point stud I88 which is fixedly mounted on the flanged member IN by Hand traverse A manually operable traverse mechanism is I provided for manually adjusting the table II longltudinally relative to the base I0. This mechanism is actuated by the manually operable traverse wheel I! which i rotatably mounted on a stud I90. A gear I9I is fixed to rotate with the hand wheel I4. The gear I9I meshes with a gear I92. Thegear I92 is keyed to a shaft I93. The shaft I93 also supports a gear I96 which meshes with a. gear I95. The gear I95 is rotatably supported on a stud I96 and meshes with a rack bar I91 depending from the under side of the, work table I I.

It is desirable to render the hand wheel I4 inoperative so that it will remain stationary during the hydraulic traverse or reciprocation of the table II. The gear I94 is preferably rotatably supported on the shaft I93 and is provided on its right-hand side face (Fig. 2) with clutchteeth I 98 which are arranged to be engaged by clutch teeth formed on a slidably mounted clutch member I99 which is slidably keyed to the shaft I93. In order to disconnect the clutch parts I98-I99, a

fluid pressure cylinder 200 is provided which con- 1 tains a slidably mounted piston 20I. The piston 20I is fixedly mounted on the right-hand end of the clutch member I99. In the position of the mechanlsm as illustrated in. Fig. 2, the clutch Headstock motor control It is desirable to provide a suitable control mechanism for automatically starting and stopping the headstock motor 32 in timed relation with the other mechanisms of the machine. Power is supplied to the motor 32 from power lines 205. A

push button switch 206 is provided for closing the motor circuit. It is preferable to provide a motor 32 which is of a variable speed type so that the speed of rotation of the work piece 21 may be readily adjusted. As shown diagrammatically in Fig. 2. an adjustable rheostat 201 is provided for regulating the speed of the motor 32. In actual construction, however, an electronic control mechanism is preferably provided, such as that for example manufactured by General Electric Company and known as the Thymotrol. A normally open limit switch 201 is provided in the motor When it is desired to disconnect the hand gitudinally extending T-shaped slot 2t! formed in circuit to facilitate automatically starting the motor in timed relationship with the other mechanisms of the machine. A hydraulically operated mechanism is provided for actuating the limit switch 208 comprising a hydraulic cylinder 2% which contains a slidably mounted piston tit. A piston ro 2 is connected at one end with the piston 21c and at the other end engages a roller 2 l 2 mounted on an actuating arm tit of the limit switch 288. A compression spring tit normally 1o maintains the piston Elli? in an uppermost position (Fig. 2) so that the switch 2% is normally open.

When fluid under pressure is passed through a pipe 295 into a cylinder chamber above the piston 2 i t, the piston 26% moves downwardly against the compression of the spring 2M3 to close the normall open limit switch ace and thus auto m'atically to start the rotation of the headstock motor at. Similarly when fluid is permitted to exhaust through the pipe 295, the released compression of the spring Zld will return theplston 2m to its uppermost position to open the limit I switch 208 and thereby stop the motor 32.

The main control valve 860 is operatively connected automatically to shift the feed control, valve 50 so as to cause either a forward or a rearward movement of the grinding wheel 62. A valve chamber 2 l 6 located between the valve pistons I63 and I613 is connected by a pipe 2i? witha valve chamber 2l8 formed at the right-hand end of the valve to. Similarly, a valve chamber are formed between the valve pistons Md and I 65 of the valve "50 is connected by a pipe 220 with a. valve chamber 22f formed at the left-hand end of the valve 80 (Fig. 2). The pipe 2i5 connects with the pipe 2H so that when fluid under pressure is passed through the pipe 2H to shift the valve til toward the left to initiate a forward feeding movement of the grinding wheel, fluid will also be passed from the pipe 2!! through the pipeltlfi to close the limit switch 208 and thereby start tion of the work piec Bl.

Table reversing valve The table reversing valve 20 is preferably a piston type reversing valve. A shuttle type reversing valve member 225 is provided having valve. pistons 225, 22? and 228 formed integrally therewith. The reversing valve 225 is preferably slidso ably mounted on a valve stem 229. A pair of independent pilot valves 23c and Hi are fixedly mounted on the right-hand end of the valve stem 229 (Fig. 2). The spool-shaped member 232 is provided with a groove 233 which is engaged by a stud 23d which is in turn fixedly mounted on a rock arm 235. The rock arm 235 is fixedly mounted on a rock Shaft 236. A table actuated reversin lever 231 is fixedly mounted on the outer end of the rock shaft 236 and is providedat its upper end with a pin .or stud 233 which is arranged to be actuated by a pair of adjustable the rota-.

" table dogs ra e and 24s. The table dogs are and 288 are adjustably supported by means of a ionas the front edge of the work table i i A motor driven fluid pressure pump 2% is provided for supplying fluid under pressure to the hydraulic system. The pump 2 55 draws fluid through a pipe 2% from the reservoir i528 and go passes fluid under pressure through a pipe 2m to the various mechanisms of the machine. A resse ses sure builds rip-beyond the predetermined pressure required, the relief valve tilt opens and by passes excess fluid under pressure directly to the reservoir Edit.

The ipe 2d? is connected to supply fluid under pressure to the table reversing valve 29. In. the.

position of the valve 2t illustrated in Fig- 2, fluid under pressure from the pipe 241 enters a valve chamber its located between the valve pistons 22% and 22? and passes out through the pipe 2 into the cylinder chamber 23 to cause the piston is and table it to move toward the right FF-*5- valve as. This valve 252 is a piston type valve comprising a valve stem 2% having formed integrally therewith valve piston 2%, eat, 25% and 25?. In the position of the valve illustrated in Fla 2, a by-pass is provided to facilitate a manual traversing of the work table it. A pipe 258 connects the valve chamber M9 in the valve 28 with a chamber 25% formed in the. stop-and start valve 252. A similar pipe 2% connects the valve chain ber 25001 the valve 28 with the chamber 259 of the stop and start valve 252. Itwill be. readily apparent from the foregoing disclosure that when the table it is traversed manually by rotation of the traverse wheel it, fluid may readily by-pass from the cylinder chamber 23' through the reversing valve 20, through the by-pass chamber 259 in the stop and startvalve 252; and into the cylinder chamber 2i, thus allowing a free manual traverse without the necessity of overcoming the resist ance of oil or fluid within the hydraulic system.

Thestop and start valve 252 is provided with a V-port 23! which is arranged so that when the valve stem 25% is moved toward the left (Fig. 2) to start hydraulic operation of the machine, fluid exhausting through the pipe 25! from the reversmay be obtained under fluid pressure. When it is desired to start a hydraulic traversing movement of the table, the start and stop valve 252 is moved toward the left by a knob 2st to open the V-port 2M which will control the rate of fluid exhausting from the table cylinder It and reversing valve the feed wheel 78.

Assuming the stop and start valve 252 has been shifted to start the table traverse, and th feed wheel to has been rotated to shift the main control valve ltd to an operative position, fluid under pressure passing through theplpe 2t? will cause the piston it and the table it tomove toward the right (Figs. 1 and 2). This movement 'will continue until the table dog 239 engages the pin tilt to rock the reversing lever 23? in a clockwise direction. This table movement serves positively to shift the valve piston 22? of the reversing valve 2%? so that it closes an exhaust port 2%. During this movement the valve member 230 engages the end of-the shuttle reversing valve member 226 and moves both valve parts so that the piston 221 closes the port 265. When the valve parts reach this position, fluid under pressure passes through a passage 266 into a chamber 201 in the valve 230.

- Fluid under pressure entering the valve chamber 261 may pass outwardly through an exhaust pipe 260 and also may pass through a passage 269 into a valve chamber 210 formed at the left-hand end of the shuttle reversing valve 225. Fluid under pressure entering the chamber 210 serves to move the shuttle type reversing valve 225 rapidly toward the right (Fig. 2) into its reverse position.

Similarly, the valve member 23l at the other end of the reversing valve 20 is provided with a valve chamber 280. A passage 28! connects the valve chamber 280 with the fluid pressure pipe 241.

A pipe 282 connects the valve 23l with the dwell control valve 215. A pipe 283 connects the valve chamber 280 of the valve 29l with a valve chamber 289 at the right-hand end of the shuttle valve 225.

The dwell control valve 215 is provided for controlling the rate of exhaust or fluid through pipes 268 and 282. Fluid from pipes 268 and 282 enters a chamber 216 in the dwell control valve 215 and passes through a V-port 211 and a pipe 218 which returns exhausting fluid into the reservoir I58. In the position of the valve 215 (Fig. 2), fluid is restricted by the V-port 211. This port may be re ulated by means of a rotary adjustment of the valve 215 by means of a knob 219. The speed of shifting of the shuttle valve 225 in either direction will be governed by the amount of fluid exhausting through the pipes 208 and 282 and the V-port 211 so that by a slight rotary adjustment or the knob 219, the extentof dwell of the work valve 225 so that the valve piston 221 covers the exhaust port 265. When the shuttle valve reaches this position, the valve 230 has moved a suflicient distance toward the right so that fluid under pressure from the pipe 251 entering the passage 266 may pass into the valve chamber 261. The port at the end of the pipe 268 has now been closed so that pressure entering the valve chamber 261 passes through the passage 269 into the valve chamber 210 to move the shuttle valve 225 toward the right into its reverse position. The speed of movement of the shifting of the shuttle valve is controlled so as to give the desired amount of dwell at the end of the table stroke. As the shuttle valve moves toward the right, fluid within the valve chamber 289 is forced out through the passage 293 into the valve chamaseasloa moved so that the valve piston 221 closes the exhaust port 265, at which time fluid under pressure from the pipe 241 will pass through the passage 28E into the valve chamber 280 and through the passage 283 into the valve chamber 200 to shift the shuttle valve 225 toward its lefthand end position. The speed of movement of the throttle valve in the left-hand direction will be controlled by fluid exhausting from the valve chamber 210 through the passage 269 and the pipe 268 which passes fluid through the V-port 211 of the dwell control valve 215.

In order that a wheel feeding movement may be obtained at reversal in a traverse grinding operation in timed relation with the table movement, it is desirable to provide a control valve to control the shifting movement of the feed control valve 95. A control valve 290 is provided. This valve is a piston type valve comprising a valve stem 29!. The arm 235 which actuates the reersing valve 20 is provided with an upwardly extending arm 292 which is provided with a stud 293. The stud 293 engages a slot 294 formed in the valve stem 29L Fluid under pressure from the pipe 251 passes through a. pipe 295 into a valve chamber 296 in-the valve 290 and in the position of the valve (Fig. 2) passes outwardly through the pipe I03 into the valve chamber 10! in the valve 95 to shift the valve 95 toward the left so that fluid under pressure within the pipe 295 may pass through the pipe into the valve chamber I00 and into the motor chamber 92 to cause the vane 88 to move in a clockwise direction into the position illustrated in Fig. 2. When the reversing her 280 and out through the pipe 282 to the dwell control valve 215. By regulating the V-port of the dwell control valve 215, the speed of movelever 231 is moved in a clockwise direction (Fig. 1) so as to cause a similar movement of the arm 235 and its extension 292, also in a clockwise direction to reverse the reversing valve 29, a corresponding reversing motion is also imparted to the-valve stem 29! of the valve 290 so that fluid under pressure from the pipe 295 entering the valve chamber 296 will pass outwardly through the pipe I06 which conveys fluid under pressure to the valve chamber 91 in the valve 95 to cause.

the valve stem 96 to move toward theright (Fig. 2). During the movement of the valve stem 96 toward the right the valve pistons are shifted so that fluid under pressure passing through the pipe I02 first enters a valve chamber 99 in the valve 95 and passes through the passage into the motor chamber 9| to cause the vane 88 to move in a counterclockwise direction so as to imart a feeding movement to the grinding wheel at both ends of the table stroke. As the valve approaches its right-hand end position, fluid under pressure entering the valve chamber 99 will pass through the passage 93 into the motor chamber 92 to return the vane 88 in a clockwisedirection into its initial position (Fig. 2). Dur- Dig the return clockwise movement of the vane 90, the ball clutch H3 slips or idles so that rotation of the gears H0 and HI during the return stroke will not be transmitted to the gear H 5.

In order to facilitate rapid adjustment of the dwell control valve 215 so that no dwell may be obtained for such operations as wheel trulng and for quick return to the predetermined table dwell for traverse grinding, an adjustable detent 300 is adjustably fastened to the front of the machine base. The downwardly extending portion of the detent 300 is arranged in the path of a stud 301 which projects inwardly from the knob 219 (Fig. 10). A stop pin 302 is fixedly mounted relative to the base of the machine and serves to limit the rotation of the knob 219 when turned in a table reversal.

counterclockwise direction (Fig. 10). When the knob 219 is turned in a counterclockwise direction so that a pin 30] engages a fixed pin 002, the valve 215 is positioned so that the V-port 211 is opened topermit a maximum exhaust of fluid from either the valve chamber 210 or the valve'chamber 299 so as to provide a rapid shifting of the reverse valve 225 witha minimum amount of dwell or no dwell at reversal. Similarly, when the knob 219 is rotatedin a clockwise direction so that the stud 30I engages the detent 300, the dwell control valve 215 will be positioned so that the V-port 211 is closed a predetermined amount toallow the desired dwell at The operation of this improved cylindrical grinding machine will be readily apparent from the foregoing disclosure; A work piece '21 is mounted 'in position on the headstock center 28 and rootstock center 29. The motor driven pump 245 is started and also the motor '43 for rotating the grinding wheel 42. The start and stop valve knob 264 is then moved toward the left (Fig. 2)

to open the V-port 29L The lever I31 is shifted in a clockwise direction to shift the gear H9 either into position I In or IIb, as above described. In case it is desired to provide a power infeed at the ends of the table stroke on a traverse grinding operation, the gear H5 is moved to position II5b. The hand feed wheel i0 isthen rotated manually in a counterclockwise direction. This movement serves through the cam IBI i (Fig. 3), "which rotates with the hand wheel 10,-

to engage the cam I19 and thereby rock the shaft I10 so as to shift the main control valve I90 toward the right (Fig. 2) to start the grinding cycle.

When the valve I60 moves to its extreme rightof the valve 95 toward the right so that fluid under pressure passing through the pipe I02 will pass through the passage 90 into the motor chamber 9 I'to move the motor vane 88 in a counterclockwise direction. This movement is transmitted through the gear mechanism in the manner above described to transmit a counterclockwise movementto the gear TI so as to impart an infeeding movement of the grinding wheel through the feed screw'50 at the end of the table stroke. During the shifting movement of the valve stem 96 toward the right, fluid passing through the pipe I02 first enters through the passage 90 to initiate an infeeding movement of v the grinding wheel. When the valve stem 96- approaches its extreme right-hand end position, fluid under pressure passing through the hand end position, fluid under pressure-ispassed through the pipe 2I1 into the valve chamber 2E9 of the valve 60 to shift the feed valve toward the 'left (Fig. 2), which movement serves to admit fluid under pressure through the pipe 9| into the cylinder chamber 82 of the feed cylinder 57 to cause the piston 98, the feed screw 50, the wheel slide 38 and the grinding wheel 42 to move forward toward an operating position. This movement continues until the piston 58 engages the end face of the cylinder 91. At the same-time as the valve I90 is moved into its right-hand end position, fluid under pressure is admitted through table II starts moving toward the right and continues movement in this direction until the dog 239 engages the pin 298 to rock the reversing lever 23! in a clockwise 'direction. This movement serves in the manner above described to shift the'reverslng valve 20 into to change the directionof' flowof fluid' under pressure to the table cylinder II. At the 'same timethe reversing valve 20 is shifted, the rock arm 235, through its extension 292 serves to shift the valve stem 29I of the valve 290 toward the right (Fig. 2), which movement serves to admit fluid under pressure through the pipe I04 into the valve chamber 91 to shift the valve stem 90 stud I24 from the hole I25 sion of the spring I40 so that the released tension:

pipe I02 and the valve chamber 99 will enter through the passage 93 into the motor chamber 92 to initiate a return clockwise movement ofthe vane 80, thus returning the vane to its initial position; During'the return'st'roke of the vane 80, the ball clutch II3 allows rotation of the gears III) and III in the reverse direction without transmitting this motion to. the gear 5 so that at each reversal of the table, the vane motor 85 rotates to cause a predetermined infeeding movement of the grinding wheel 42 and then returns idly to its initial position, such as shown in Fig. 2 of the drawings;

This cycle of operationis continued and the table Ii allowed to reciprocate until the work piece has been ground to the desired and predetermined extent, that is, until the stop abutment I22 on the feed wheel I0 engages the stop abutment I M b which positively limits the 'infeeding movement of the the feed screw 90.

When the grinding operation has been completed, the operator shifts the lever I31 toward the front of the machine, that is, in a counterclockwise direction (Fig. 6) todraw the latch of the spring will return the feed gear II5 into full line position (Fig. 3). The hand feed wheel I0 may then be rotated in a counterclockwise direction until the cam face I80 engages the cam face I I8 to rock the member I72 and thereby to rock the shaft I10 and main control valve piston I6I into its left-hand end position,-such as shown in Fig. 2. The shifting of the valve I60 into this positionserves to admit fluid under pressureithroughthe pipe 220 to shift the feed control valve 60 under the in-. fluence of fluid pressure into its right-hand end position (Fig.2) so that fluid is admitted through the pipe 64 into the cylinder chamber 63 to cause the piston 90 and the grinding wheel slide 38'to move rearwardly to an inoperative position. At

the same time, fluid is permitted to exhaust from the cylinder chamber through the pipe 2I5 so that the released compression ofthe spring 2M its reverse position serves to allow the limit-switch 298 to open, thus stopping the rotation of the work drive motor.

When it is desired to traverse the table II manually, the .stop and start valve 252 must be shiftedtoward the right into the position 'illustrated in Fig.- 2 so that fluid under pressure may exhaust from the cylinder chamber 204 to allow the released compression of the springs 202 to move the clutch member I99 toward the left into the position illustrated in Fig. 2 so that rotation of. the manually operable traverse wheel I4 will impart a longitudinal motion to the rack bar I91 grinding wheel as imparted by whichreleases the ten- I the arm I69 to shift the and the table I I through the traverse gear mechanism above described.

It will thus be seen that there has been prosuccessfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts,. all

without departing from the scope of the invention, it is to be understood that all. matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative andnot-in alimitingsense.

I'claim: i. In a grinding machine having a base, a

I reciprocable table thereon, a piston and cylinder motor to produce an lnfeeding movement of the' to reciprocate'said'table and a reversing valve therefor comprising a control valve having a table-actuated valve stem, a reversing valve slidably mounted on said valve stem, a pilot valve fixedly mounted on each end of said. valve stem to control the shifting movement of the reversing valve, valve chambers located between the pilot valves and the ends of said reversing valve, and a .dwell control valve connected with each of said pilot valves which is arranged. to control the shifting of the reversing valve so as to pro duce the desired dwell during table reversal.

2. In a grinding machine having a base, a reciprocable table thereon, a piston and cylinder nism therefor comprising a control valve having a table actuated valve stem, 2. pilot valve fixedly to reciprocate said tableand a reversing mechamounted adjacent to each end of said stem, a

reversing valve between said pilot valves which is slidably mounted on said valve stem, valve chambers between the pilot valves and the ends of said reversing valve, and a dwell control valve connected with each of said pilot valves, said parts being arranged so that the table movement positively shifts the valve stem, pilot valves and reversing valve until the reversing valve cuts ed the exhaustof fluid from said cylinder, in which position one of said pilot valves admits fluid under pressure to the adjacent valve chamber to shift the reversing valve into its reverse position and said second pilot valve connects the other of said valve chambers to the dwell control valve which controls the rate of shifting of thereverse valve intoa reverse position.

3. In a grinding machine having a base, a

- reciprocable table, a piston and cylinder to reciprocate said table and. a reversing mechanism therefor including a control valve having a slidably mounted valve stem, a reversing lever to actuate said stem, adjustable table dogs on said table to actuate said lever, a pilot valve fixedly mounted adjacent to each end of said valve.

4 stem, areversing valve between said pilot valves whichis slidably mounted on said valve stem, valve chambers between the pilot valves and the ends of the reversing valve, anda dwell control valve operatlvely connected with each of said pilot valves, said reversing lever being arranged tlvely connected to the dwell control valve so as to' produce the desired dwellduring table reversal. Y i v 4. In a grinding machine having a base, a reciprocable table thereon, a-piston and cylinder to reciprocate said table, a table actuated re-. versing valve therefor,-v a transversely movable slide, a rotatable grinding wheel thereon, a nut and screw feed-mechanism for said slide, means including a vane type fluid motor to actuate said feed mechanism, a fluid pressure actuated control valve for said motor, a pilot valve whichis actuated in timed relation with said reversing valve to admit fluid to actuate said control valve during reversal of the table to cause an infeeding movement of the grinding wheel at the ends of the table stroke, a main control valve which is operatively' connected to, start said tablereciprocation and torender operative the vane type grinding wheel at each reversal of the table, and a manually operable feed wheel to rotate said screw and to actuate said main control valve to initiate a grinding cycle.

5. In a grinding machine having a base, a reciprocable table thereon, a piston and cylinder to reciprocate said table, a reversing valvethere: for, a table actuated reversing lever toactuate said reversing valve, a transversely movable wheel slide, a rotatable grinding wheel thereon,

the pilot valve is actuated during reversal at the ends of the table stroke to cause an infeeding a manually operable feed wheel which is operamovement of the grinding wheel during reversal, a main control valve which is operatively connected to start said table reciprocation and to render operative the vane type motor to produce an infeed of the grinding wheel at reversal, and

tively connected to rotatesaid feed screw and to actuate said main control valve to initiate a grinding cycle.

6. In a grinding machine having a base, a

longitudinally movable work table thereon, a piston and cylinder to reciprocate said table, a control valve therefor, a start and stop valve to control the exhaust of fluid from-said cylinder, a rotatable grinding wheel, a transversely movable slide on said 'base,-a rotatable grinding wheel on said slide, a piston and cylinder tomove said slide rapidly to position said slide, a control valve therefor, means including a vane type fluid motor. to'feed said'slide at a grinding speed, a control valve therefor, a pilot valve which is actuated by and in timed relation with the table control valve to actuate said latter control valve so as to produce aninfeeding movement of the grinding wheel. at each end of the table stroke, and a main control valve which is operatively connected to initiate a rapid approaching movement of the grinding wheel to start the table reciprocation and to render operative the vane type motor to produce an infeed of the grinding wheel at reversal,

7. In a grinding machine having a base, a reciprocable table thereon, a piston and cylinder to reciprocate said table, a control valve therefor, a start and stop valve to control the exhaust of fluid from said cylinder, a transversely movable grinding wheel slide on said base.

a rotatable grinding wheel on said slide, a pisaeeaeoa ton and cylinder to move said slide rapidly to position said grinding wheel relative to a work type motor to produce an infeeding movement of the grinding wheel at reversal.

8. In a grinding machine having a base, a longitudinally reciprocable table, a piston and cylinder to reciprocate said table, a control valve therefor, a start and stop valve to control the. exhaust of fluid from said cylinder, a transversely movable grinding wheel slide on. said base, a rotatable grinding wheel on said slide, a nut and screw feed mechanism for said slide, a piston and cylinder to move said screw in an axial direction rapidly to position the grinding wheel relative to a work piece to be ground, motor, a piston and cylinder to reciprocate said means including a vane type motor to rotate said feed screw, a control valve therefor which is actuated by and in timed relation with the reverse valve to produce an infeeding movement of the grinding wheel at the ends of the table stroke, a main control valve which is operatively connected to initiate a rapid approaching movement of the grinding wheel to start the table Elli reciprocation and to render operative the vane type motor to produce an infeeding movement of the grinding wheel at reversal, and a man; ually operable feed wheel which is operatively connected to rotate said feed screw and to actuate said main control valve to initiate a grinding cycle.

9. In a grinding machine having a base, a longitudinally reciprocable table thereon, means including a manually operable hand wheel to traverse said table longitudinally, a rotatable work support including an electric motor driven work support on said table, means including .a fluid pressure operated switch to control said motor, a piston and cylinder to reciprocate said table, a control valve therefor, a stop and start valve to control the exhaust oi fluid from said cylinder, a transversely movable grinding wheel slide on base, a rotatable @131: g wheel on said slide, a nut screw feed piston and cylinder to move said feed screw axially rapidly to position the grinding wheel relative to a work piece to be ground, a control valve therefor, means including a vane type motor to rotate said feed screw, a-control valve therefor which is actuated by and in timed relation with the reversing valve to produce an infeeding movement of the grinding wheel at the ends of the table stroke, and a main control valve which is operatively connected to actuate said first control valve so as to initiate a rapid approaching movement of the grinding wheel to start the work drive motor, to render the manual traverse wheel inoperative, to start the table reciprocation, and to render operative the vane type motor so as to produce an infeeding movement of the grinding wheel at reversal.

l0. In a grinding machine having a base, longitudinally reciprocable table thereon, means including a manually operable hand wheel to traverse said table longitudinally, a rotatable worksupport including an electric motor driven work support on said table, means including a fluid pressure operated switch to control said table, a control valve therefor, a stop and start valve to control the exhaust of fluid from said cylinder, a transversely movable grinding wheel slide on said base, means rotatably to support a grinding wheel on said slide, a nut and screw feed mechanism, a piston and cylinder to move said feed screw axially rapidly to position the grinding wheel relative to a work piece to be ground, a control valve therefor, means including a vane type motor to rotate said feed screw,

a control valve therefor which is actuated by and in timed relation with the reversing valve to produce an inieeding movement of the grinding wheel at the ends of the table stroke, and a m main control valve which is operatively connected to actuate said first control valve so as to initiate a rapid approaching movement of the grinding wheel to start the work drive motor,

to render the manual traverse .wheel inoperative, I

$5 to start the table reciprocation, and to render operative the vane type motor to produce an infeeding movement or the grinding wheel at reversal, and a manually operable feed wheel which is 'operatively connected -to rotate said feed screw and to actuate said main control valve to initiate a grinding cycle. v

A, SILVEI T,

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