US2387044A

US2387044A - Surface grinding machine

Info

Publication number: US2387044A
Application number: US561401A
Authority: US
Inventors: Herbert A Silven
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1944-11-01
Filing date: 1944-11-01
Publication date: 1945-10-16
Anticipated expiration: 1962-10-16

Description

Oct. 16, 1945. Q H.'A. SILVEN 87,

SURFACE GRINDING MACHINE I Filed Nov. 1, 1944 '7 sheets-sheet 1 HERBERT A. Suva.

ltwwuuea Oct. 16, 1945. 'H. A. SILVEN SURFACE GRINDING MACHINE F iled Nov. 1, 1944 '1 Sheets-Sheet 2 o HERBERT A. \S/LVEN Mum Oct 1945- H. A. SILVEN 2,387,044

SURFACE GRINDING MACHINE Filed Nov. 1, 1944 7 Sheets-Sheet 3 awe/whom HERBERT A.I-SILVEN WLD-W Oct. 16, 1945. A um 2 ,387,044

SURFACE GRINDING MACHINE Filed Nov. 1, 1944 7 Sheets-Sheet 4 Zlfob HERBERT A; 5/1. VEN

' awuc/wtm 16, 1945- H. A. SILYIEN 2,387,044

SURFACE GRINDING MACHINE Filed Nov-.'1-, 1944 '7 Sheets-Sheet 5 HERBERT A. \S/LVEN Wm-wan Gamma;

Oct. 1-6, 1945. H. A. SILVEN 38 SURFACE GRINDING MACHINE Filed Nov. 1, 1944 7 Sheds-Sheet 6 mmN Oct. 16, 1945.

H. A. SILVEN 2,387,044

SURFACE GRINDING MACHINE Filed Nov. 1, 1944 v 7 Sheeos-Sheet 7 HERBERT A. S/LVEN Patented a. 16, 1945 SURFACE GRINDING MACHINE Herbert A. Silven, Worcester, Mass.. m nor to Norton Company, Worcester, Man, a corporation of Massachusetts Application November 1, 1944, Serial No. 561,401

16 Claims.

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

One obiectof the invention is to provides simple and thoroughly practical surface grinding machine for grinding predetermined plane surfaces on a work piece. Another object of the invention is to provide a surface grinding machine in which a predetermined grinding cycle may be obtained, that is, a predetermined relative longitudinal and transverse movement between the grinding wheel and the work piece to grind a predetermined plane face on a work piece. Another object of the invention is to provide ,a surface grinding machine having two opposed spaced grinding wheels which may be successively positioned in predetermined positions for grinding opposed parallel plane faces on a work piece. Another object of the invention is to provide a surface grinding machine in which the work piece to be ground is mounted on an indexable work holder which is in turn supported on transversely and longitudinally movable work supporting tables by means of which the work piece may be moved through a predetermined cycle to grind a predetermined plane surface on a, portion of the work piece and the work piece may be indexed to present a plurality of predetermined portions for grinding.

A further object of the invention is to provide a truing apparatus having opposed truing tools arranged for simultaneously truing the operative faces of two opposed grinding wheels in which the 'truing tools are maintained in a fixed position for a truing apparatus so that it is not necessary to'reset the wheel positioning mechanism after a truing operation has been performed. Other objects will be apparent from the foregoing disclosure.

The invention accordingly consists in the features of construction, combinations "of elements, and arrangements of parts, as will be exemplified in the structure to behereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompany n drawings, in which is.

shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of the improved surface grinding machine;

Fig. 2 is a diagrammatic illustration of the hydraulic control and actuating mechanisms of the machine;

Fig. 5 is a fragmentary front'elevation. on

.an enlarged scale, of. the control apron, showview, on an enlarged scale, taken approximately on the line 8-9 of Fig. 8;.

Fig. 10 is a fragmentary plan view. on an enlarged scale, of the grinding wheel truing apparatus;

Fig. 11 is alongitudinal sectional view, taken approximately on the line li--ll of Fig. 10,

through thetruing apparatus;

Fig. 12 is a fragmentary front elevation, on an enlarged scale, of the truing apparatus as shown in Fig. 1;

Fig. 13 is a fragmentary cross-sectional view, on an enlarged scale, taken approximately on the line I Il 3 of Fig. 10'; and

Fig. 14 is a diagrammatic illustration showing the relationship of the opposed grinding wheels and the truing tools therefor.

A grinding machine has been illustrated in the drawings comprising a base ill which-supports a longitudinally movable work table Ii on suitable slideways (not shown). A transversely movable table I2 is supported on slideways formed on the upper surface of the longitudinally movable table II, said slideways being arranged so that a work piece supported on said transversely movable table may be moved either longitudinally or transversely for a grinding operation.

The base In is provided with an upwardly extending column l3 which supports a vertically movable slide I 4 having suitable slideways formed between the slide l4 and the column H. The

slide i4 serves as a support for a vertically arranged grinding wheel spindle I! which in turn supports a pair of spaced grinding wheels I! and I1, the grinding wheels l6 and I1 being arranged successively to grind an upper and a lower surface on a work piece'l8. The work piece it is providedwith a plurality of webbed portions l9 having upper and lower parallel plane surfaces to be ground to a predetermined extent.

Longitudinal table traverse The longitudinally movable table II is provided with a hydraulically operated traversing mechanism comprising a cylinder 20 which is fixed relative to the base it. A slidably mounted piston 2i is provided in the cylinder 20 and is fixedly connected toa double end piston rod 22 will be. readily apparent from closure that movement of the 4 41 toward .or-away iromr t which extends through opposite end caps on the cylinder 28 and is fastened at its outer ends to depending brackets 23 and 24 which are fixedly mounted on the under side of opposite ends of the longitudinally movable table H. v

A control valve 25 is provided for controlling the admission to and exhaust of fluid from the cylinder 28. The valve 25 is preferably a piston type valve comprising a valve stem 28 having formed integrally

therewith valve pistons

21, 28 and 29. A manually operable cycle control lever 30 is pivotally supported on a stud 3i which is fixed relative to the base Ill. The lever 88 is provided with a stud 32 which rides in a comparatively wide groove 83 in a spool-shaped member 38. The lower end of the lever 38 is provided with a V-shaped end portion 35 which engages a spring-pressed roller 38. The groove 83 formed on the spool 84 is wide enough so that when the lever 38 is moved to reverse the position of the valve 25, the lever is moved until the high point of the arrow 85 passes the axis of the spring-pressed roller 38, after which the released compression of the springpressed roller will shift the valve stem 28 into its reverse position. The lever 38 serves as a cycle control lever to initiate a grinding cycle, as will be hereinafter described.

The control lever 38 is fixedly mounted on the outer end of a rock shaft 3|. The inner end of the rock-shaft supports a bevel gear 31 which meshes with a bevel gear 31a mounted on a rotatable shaft 38. An actuating lever 39 is mounted on the left-hand end of the shaft 88 (Figs. and 8).. The lever 38 is actuated, in a manner to be hereinafter described, by a dog mechanism carried by the transversely movable table i2.

Stop and start value A manually operable stop and start valve 48 is provided for stopping the hydraulic operation of the machine or starting the same when desired. This valve is a piston type valve comprising a valve stem ll having formed integrally therewith

valve pistons

42, 43;, 45 and A8. A manually operable control lever 41 is pivotally supported on a stud 48 which is fixed relative to the base of the machine; The lower end of the lever 81 is provided with a. stud 48 which rides in a groove 58 formed in a spool-shaped member 5| which is fixedly mounted on the end of the valve stem 8| ,In actual construction, as illustrated in Figs. 8 and 9, the stop and start lever 41 is operatively connected by a stud "a with a slidably mounted rod l'lb. A stud 41c isflxedly mounted on the rod 41b. The stud llc rides in a cam slot 48a formed in a pivotally mounted'lever 48b which is pivotally mounted at one end b is fixed relativetothe base i l. .The stud-is mounted on the opposite end of the'lever 4822. It

the foregoing disstart and stop lever he machine will be transmitted through the oactuate @the start stop valve 48.

Troasoerse'table traverse j v ansverselymovable slide i2 is preferabl'y aperlaited by meansiof. a'fiuid presy movable slide 1' l. ,A- piston er 52 and isilxedly connected with a double end y-a stud 48c which mechanism ,above de- I brackets 55 and 58 which are fixedly supported on the under side of the opposite ends of the transversely movable table 12.

A control valve 51 is provided for controlling the admission to and exhaust of fiuidfrom the cylinder 52. This valve is a piston type valve comprising a valve stem 58 having iormed integrally therewith

valve pistons

59, 88 and 8!. An actuating lever 82 is pivotally mounted on a stud 88 which is fixed relative to the base of the machine. The lower end of the lever 82 is provided with a narrow-pointed projection 84 which engages a spring-pressed roller 85. The springpressed roller 85 is arranged to serve as a load and fire mechanism to shift the valve rapidly into a reverse position. The control lever 82 is provided with a stud 85 which engages a relatively wide groove 81 formed in a spool-shaped member 88 .which is fixedly mounted on the end of the valve on is fixedly-mounted relative 4 I piston rod sermon extends through the opposite end caps I ot cylinder- 52. The opposite of the con--.

i H o nec d-y n en n s:

relative tofthe base l8.- flhe l a stud 84 which rides in a groove." spool shaped member 88 which n on the end of the valve stem 18.

w r apparent irom the fore oing discl ual movement of the lever-l2 from the full-line tion 82a win stem 58. The relatively wide groove 81 is provided so that the lever 82 may be moved positively until the arrow-shaped portion 84 rides over the top of the spring-pressed roller 85 without moving the valve stem 58, after which the released compression of the roller 85 rapidly shifts the valve 51 into its reverse position.

The lever 52 is automatically actuated by a pair of adjustable table does 88 and 880 which are adjustably mounted on the front edge of the longitudinally movable work table H.

Grinding wheel feed' The upper end of the piston rod .12 is fixedly connected to a bracket 18 which is in turn fixedly mounted on-the vertically movable wheel slide H.

A hydraulically operated counterbalance mechanism is provided to counterbalance the weight of the vertically movable wheel slide I 4 so as to facilitate movement of the same either by power or by hand. This mechanism comprises a counter-balance cylinder 15 which'contains a slidably mounted piston 18, the slidably mounted piston 18 being fixedly connected to the lower end of the piston rod 12. Fluid under pressure is at all times maintained within a cylinder chamber II, the pressure of such fluid being suflicient to counterbalance the weight of the wheel slide it and its associated parts.

A wheel feed control valve 11 is provided for controlling the admission to and exhaust of fluid from the cylinder III. This valve is a piston type v vecomprising a valve stem l8 having formed integrally therewith

valve pistons

19, 88 and 8|. A manually operable control lever 82 is pivotally supported by a stud 83 which is ever 82 supports io'rmed in a is fixedly mounted It will be readily osure that'man- Fig. 2 into position as indicated in' the valve 1 Mat dotted'llne posi- 0 its reverse position. V I

W rk iadesmechanism}; In order, to facilitate grinding a work Piece.

such as thework fixedly mounted we new. w

portions or webs I to be ground, it is desirable to provide a work piece indexing mechanism whereby after the first portion or web I8 has been ground, the work piece I8 may be precisely indexed to present the next portion or web I8 01' the work piece I8 into operative relation with the grinding wheels I6 and I1. The work piece I8 is preferably mounted on a rotary indexing mechanism comprising an index plate 80 which is provided with a plurality of spaced notches 8| which correspond with thenumber or portions and angular positions of the portions on the work piece III to be ground. .A holding pawl 82 is provided for locating and holding the index plate 80 in a predetermined grinding position. An index pawl 93 is pivotally mounted on a swinging arm 04. The pawl 03 and arm 94 are preferably hydraulically actuated so as to facilitate a rotary indexing of the plate 90. This mechanism may comprise a hydraulic cylinder 85 having a slidably mounted piston 96 which is connected to the left-hand end of a piston rod 91. The right-hand end of the piston rod 81 is connected by a stud 98 which is carried by the index pawl 93. I

An index control valve I00 is provided for controlling the indexing movement of the work piece. This valve is a piston type valve comprising a valve stem IOI having iormed integrally therewith valve pistons I02, I03 and I04. A manually operable control lever I is pivotally mounted on a stud I05 which is fixed relative to the base of the machine. The control lever I05 carries a stud I01 which rides in a groove I03 formed in a spool-shaped member I00 which is fixedly mounted on the right-hand end of the valve stem II. It will be readily apparent that manual actuation of the lever I05 serves to control the position of the valve stem I 00. A compression spring is provided within the letthand end of the valve I00 (Fig. 2) normally to maintain the valve in its right-hand end position.

Hydraulic, system A hydraulic system is provided for operatively conveying fluid under pressure to and from the several mechanisms hereinabove described. This system comprises a motor driven pump H0 which draws fluid from a suitable source of supply such as, for example, a reservoir (not shown) formed either within or outside of the base I0, through a pipe III. The pump H0 forces fluid under pressure through a pipe H2 which is connected to pass fluid under pressure through a pipe H3 into a chamber H4 formed between the valve pistons 45 and 46 in the stop and start valve 40. A pipe H5 connects the valve chamber H4 in the stop and start valve 40 with a chamber H6 formed between the

valve pistons

28 and 29 in the longitudinal table control valve 25. In the position of the valve 25 as shown in Fig. 2, fluid under pressure entering the valve chamber H6 is forced through a pipe H1 into a cylinder chamber H8 formed at the right hand end of the cylinder 20 so as to move the piston 2I and the table II longitudinally toward the left. During this movement of the table II,

fluid within a cylinder chamber H9 formed at the left-hand end of the cylinder 20 exhausts through a pipe I20, into a chamber I 2I formed between the pistons 21 and 28 in the valve 25,

and passes outwardly through a pipe I22.

Fluid under pressure passing through the pipe H5 from the stop and start valve 40 also passes through a pipe I25 into a valve chamber I20 formed between the valve pistons 00 and GI in the transversely movable table control valve 51. In the position of the valve (Fig. 2), fluid entering the valve chamber I26 passes outwardly through a pipe I21 and through a pipe I28 into a cylinder chamberI28 formed in the upper end of the cylinder 52 (Fig. 2) to move the piston 53 and the table l2 transversely in a downward direction, as shown diagrammatically in Fig. 2. Durlng this movement of the transversely movable table I2, fluid within a cylinder chamber I30 formed at the lower end of the cylinder 52 exhausts through a pipe I3I which is connected with a valve chamber I32 in the control valve 51. In the position of the valve 51 (Fig. 2) exhaust fluid entering the chamber I32 passes outwardly through a pipe I33 into a, valve chamber I34 formed in the stop and start valve 40 and retsurns to the source of supply through a pipe I3 Fluid under pressure passing through the pipe H2 also enters a valve chamber I36 formed between the valve pistons and 0| in the wheel feed control valve 11. In the position of the valve 11 (Fig. 2), fluid under pressure entering the valve chamber I36 passes outwardly through a pipe I31 into a cylinder chamber I38 formed in the upper end of the cylinder 10 so as to cause a downward movement of the piston II and the wheel slide I4. During the downward movement of the piston 1 I, fluid within a cylinder chamber I39 exhausts through a pipe I40 which is connected with a valve chamber MI formed between the valve pistons 19 and B0 in the control valve 11 and passes outwardly through an exhaust pipe I42 into the source of supply or reservoir.

Fluid under pressure within the pipe H2 also passes into a valve chamber I43 formed between the valve pistons I02 and I03 in the work index control valve I00. Fluid entering the valve chamber I43 passes out through a pipe I44 into a cylinder chamber I45 formed at the left-hand end of the cylinder to cause the piston 86 to move toward the left (Fig. 2) into an inoperative position. During movement of the piston 95 toward the left, fluid within a chamber formed at Slow down valve It is desirable to provide a suitable control for fluid exhausting from the longitudinal table cylinder 20 so that the movement of the table may be readily controlled. A slow-down valve I48 is provided which is a piston type control valve having a valve stem I49. The valve stem I49 is operatively connected with a roller I50 which is arranged to be actuated by a pair of table dogs I5I and I52. The dogs I5I and I52 are adjustably supported on the front edge of the longitudinally movable table I I. In the position'of the valve I48 (Fig. 2), fluid exhausting from the cylinder chamber H9 passes through the valve chamber I2I in the table control valve 25 and exhausts through the pipe I22 into a valve chamber I53 in the slow-down valve I48 and passes outwardly through a pipe I54 into the exhaust pipe I33. In this position of the valve (Fig. 2), substantially unrestricted exhaust of fluid is permitted so as to produce a comparatively rapid longitudinal movement of the table II. As the table moves to bring the web I! of the work piece I into ,operative grindingrelationship with the grinding wheels I6 and I1, a cam face I55 on the dog I5 I depresses the roller I50 which in turn moves the valve stem I 49 downwardly (Fig. 2) so as to cut off the exhaust of fluid through the pipe I54 and to permit fluid to exhaust through a pipe I56 anda throttle valve I51 so as to slow down the traversing movement of the table II to a grinding speed. By adjusting the throttle valve I51, the grinding feed of the work relative to the wheel may be adjusted as desired.

When the control valve 25 is shifted into its reverse position to cause the table II to move toward the left after the work piece has been traversed transversely relative to the grinding wheel, it is desirable that the initial movement of the table H toward the left he maintained at a slow grinding speed until the work piece I 8 has traversed out of engagement with the grinding wheels I6 or I1. In the reverse position of the valve 25, fluid exhausting from the table cylinder chamber II8 passes through the pipe H1, the valve chamber II 6, and out through a pipe I58 and through a throttle valve I59 into the exhaust pipe I33. By regulation of the throttle valve I59, the grinding traverse of the table II toward the left (Figs. 1 and 2) may be regulated to correspond with the movement of the table I I in the opposite direction. When the work piece I8 moves out of operative contact with the grinding wheels I6 or I1 as the table II moves toward the left, the cam face I55 of the dog I5i allows the roller I50 to move upwardly under the released com- Dression of a compression spring located adjacent to the top of the valve I 48, thus allowing the valve I46 to return to the position illustrated in Fig. 2 so that substantially unrestricted exhaust of fluid may be obtained by passing the exhaust fluid through a valve chamber I60 and out through a pipe I6I which connects with exhaust pipe I33.

The dog I 5| is formed with a flat lower surface I55a which is positioned to hold the valve I40 in a downward position (Fig. 2) so that fluid exhausts at a relatively slow rate through the throttle valve 151. When the table II approaches the end of its stroke toward the right (Fig. 2) just before the sleeve I91 engages the end cap at the left-hand end of the cylinder 20, it is desirable to cut oil the exhaust of fluid from the cylinder so that the fluid serves as a cushion to prevent shocks and vibrations as the table II is stopped. This is preferably accomplished by providing a portion I 55b on the dog I5I so that as the feeding movement is stopped, the roller I50 is per-.

mitted to rise a suflicient distance so as to cut oil exhaust of fluid through the pipe I56, thus stopping the entire exhaust of fluid from the cylinder 20 at the time the sleeve I91 reaches a stopped position.

The slow down valve 148 and associated parts is shown diagrammatically in Fig. 2. In actual construction, as illustrated in Fig. 5, the roller I50 is rotatably supported at the upper end of a slidably mounted rod 2". Thelower end of the rod 21I is connected by a stud 212 with an arm 213 of a bell crank lever 214. The bell crank lever 214 is pivotally supported on a rock shaft 215. A downwardly extending arm 216 of the bell crank lever 214 is connected by a stud 211 with a spool-shaped member 218 which is mounted on the valve stem I49 of the slow down valve 146. A manually operable lever MI is fixedly mounted on the outer end of the rock shaft 216.

aaeam Relief valve An adjustable pressure relief valve I64 is arranged in the pipe line III to facilitate maintaining the desired operating pressure within the hydraulic mechanisms above described. After the pressure within the system reaches the pressure set by the valve I64, the valve opens and allows excess fluid under pressure to pass through the pipe I65 into the cylinder chamber 11 to act upon the piston 16 and thus counterbalance the weight of the wheel slide I4. In order to regulate the pressure utilized for counterbalancing, fluid within the cylinder chamber 11 is connected by a pipe I66 with a second adjustable pressure relief valve I61. By regulating the valve I61, the desired counterbalance ressure may be secured within the chamber 11 so as to counterbalance the weight of the slide l4 and its associated parts. Excess fluid under pressure within the counterbalance cylinder 15 will open the valve I61 and allow the excess fluid under pressure to exhaust through a pipe I68 into the reservoir.

As shown diagrammatically in Fig. 2, the counterbalance cylinder 15 appears to be the same diameter as the feed cylinder 10 but in actual practice the counterbalance cylinder 15 is considerably larger in diameter so as to provide a large Piston area for the counterbalancing operation. In order to compensate for quick vertical motion of the feed piston 1| so that the chamber 11 will always be maintained full of oil on the up stroke, a check valve I69 is connected in the pipe line I66. A pipe leads from the check valve I69 into the reservoir. If there is any tendency to create a vacuum within the cylinder chamber 11, due to rapid movement of the wheel slide I4, fluid is sucked up through the pipe and the check valve I69 into the cylinder chamber 11 to maintain the chamber 11 filled at all times.

Hand traverse-longitudinal table front of the machine base. The hand wheel I10 is connected through a clutch mechanism comprising a slidably mounted clutch member III (shown diagrammatically in.Fig. 2) and a clutch member 112 which is mounted on one end of a rotatable shaft I13. The shaft I13 also supports a gear or pinion I14 which meshes with a rack bar (not shown) which is fixedly supported on the under side of the table II. A compression spring I15 serves normally to hold .the clutch member I H in engagement with the clutch member I12.

During hydraulic operation 01' the table, it is desirable that the clutch be disconnected so that the hand wheel I10 will not turn during the power traversing movement of the table II. This is preferably accomplished by a hydraulically operated mechanism. Fluid pressure entering the valve chamber I I4 of the stop and start valve I40, in the position of the valve shown in Fig. 2, passes out through a pipe I16. into a cylinder chamber I-11 to move the clutch member I1I downwardly (Fig. 2) against the compression of the spring I15 to maintain the hand wheel I10 disengaged while the hydraulic operating mechanisms are operative.

machine and render the manual traverse mecha- Hand traverse-transverse table A similar manually operable traverse mechanism is provided to facilitate manual adjustment of the transversely movable table I2. This mechanism may comprise a manually operable rotatably mounted hand wheel I80 which is rotatably supported in fixed relation with the longitudinally movable table II. The hand wheel I80 is mounted on the outer end of a rotatable shaft III. The inner end of the shaft I8I supports a clutch member I82 which is normally maintained in engagement with a clutch member I83 by means of a compression spring I84. The clutch member I83 is fixedly mounted on the lower end of a rotatable shaft I85. The'other end of the shaft I85 is provided with. a gear or pinion I88 nisms operative, the pipes I84 and I95 will be connected through the valve chamber I98 so that fluid may readily by-pass between the opposite end chambers H8 and .I I9 of the cylinder 20. In this position of the parts, the table II may be readily which meshes with a rack bar (not shown) to move the transversely movable table I2 relative to the longitudinally movable table I I. In actual Y construction a gear mechanism is interposed between the hand wheel 80 and the clutch part 82.

Since this mechanism is not considered to be a part of the present invention, the diagrammatic start lever 41 is moved in a counterclockwise direction to shift the valve stem 4I toward the right (Fig. 2), which movement shifts the valve piston 45 so that fluid within the cylinder chambers I11 and. I 88 may exhaust through pipes I18 and I81 through a valve chamber I89 located between the valve pistons 44 and 45 and exhaust through a pipe I98 into the reservoir. As soon as the stop and start valve is moved into this position, the released compression of the springs I15 and I84 engages the clutch parts I1I-I12 and I82I83 so as to render the manually operable traverse wheels I18 and I80 operative.

During the manual traverse of the longitudinally movable table II and the transversely movable table I2, it is desirable to provide a suitable fluid pressure by-pass so that the manual traverse may be accomplished without overcoming resistance of the fluid within the hydraulic system. As shown in Fig. 2, a pipe I9I connects thepipe' I28 with a valve chamber I93 in the stop and start valve 40. A pipe I92 connects the pipe I3I with the valve chamber I93. When the stop and start lever 41 is moved in a counterpipes above described into the chamber I30 and vice V6138.

Similarly, a by-pass is provided for the cylinder 28. A pipe I94 is connected between the pipe H1 and a valve chamber I 98 in the stop and start valve 40. A ipe I95 is connected between the pipe I 20 and the valve chamber I98. When the valve 40 is shifted into its right-hand end position to stopthe hydraulic operation of the traversed manually by rotation of the hand wheel I18.

Work table-stop mechanism It is desirable to provide suitable stops for preon the left-hand end of the cylinder 28 which serves as a positive stop to limit the infeeding movementof-the table II.

Similarly, a stop sleeve mounted on the piston rod 54 and serves to limit the movement of the transversely movable slide I I2 toward the rear of the machine,that is, in an up direction in Fig. 2. When the slide I2 moves toward the rear to traverse the work piece relative to the grinding wheels, this movement continues at a grinding speed until the sleeve I98 Wheel slide-stop mechanism As above stated, the machine is arranged for grinding an upper and a lower plane surface on webs I9 projecting from a work piece I8. Opposed spaced grinding wheels I8 and I1 are provided. The wheel slide I4 is first moved downwardly to grind the upper surface of the web I9. After all of the upper surfaces of the webs I9 have been ground to the desired and predetermined extent, the wheel slide I4 may be moved upwardly to position the lower wheel I1 in proper position for grinding the lower surfaces of the webs I9. It is desirable to provide suitable stop mechanisms for precisely determining the up and down posi-' tion of the wheel slide I4 so that the wheels I8 and I1 may be precisely positioned for the grinding operation. As illustrated in Fig. 2, the piston rod 12 is provided with a threaded portion I99 which serves as a feed screw. A sleeve 208 is screw threaded onto the feed screw I99. A

worm gear 28I is slidably keyed to the outer periphery of the sleeve 288. The worm gear 20I is held against axial movement so that the piston rod 12 and the sleeve 288 are free to move in an shown in the expired patent to Norton, No. 762,--v

838 dated June 14, 1904. The feed wheel is provided with a micrometer adjusting mechanism 204 and a stop (not shown) by means of which the feed wheel 283 may be turned to a predetermined position precisely to adjust the position of the upper grinding wheel I8. The lower end of the sleeve I98 is adjustably 200; when moved downwardly, engages the end cap of the cylinder 10 and serves as a positive stop to limit the downward feeding movement of the wheel slide I l and the grinding wheel it. To compensate for wear on the grinding wheel l0, it is merely necessary to adjust the hand wheel 203 to reposition the stop sleeve 200 so as to allow the wheel slide ll and the grinding wheel I to move to a slightly lower position.

A similar feeding mechanism is provided to control the upward feeding movement of the slide N and the grinding wheel I! to position the grinding wheel I! in a predetermined position relative to the under surface of the web l3 on the work piece l8 to be ground. The piston rod 12 is provided with a second feed screw 205. A stop sleeve 20! is screw threaded onto the feed screw 206. A worm gear 208 surrounds the sleeve 20'! and is slidably keyed to the outer periphery thereof. A worm 200 meshes with the worm gear 208. A manually operable feed wheel is mounted on the outer end of the shaft supporting the worm 200. This feed wheel 2|0 is provided with the usual micrometer adjusting mechanism 2 and a stop (not shown) for limiting the rotary movement of the feed wheel 2|0. When the wheel slide l4 and grinding wheel H are moved in an upward direction, the feeding movement continues until the upper end of the sleeve 20! engages the end face of the cap enclosing the lower end of the cylinder which serves asa positive stop to limit the upward feeding movement of the grinding wheel assembly precisely to position the operative face of the grinding wheel I! relative to the lower face of the web I! to be ground. It will be readily apparent that by adjustment of the hand wheel 2 I 0, the position of the stop sleeve 201 may be readily adjusted so as to compensate for wear of the grinding wheel H.

In order to automatically shift the lever 30 in timed relation with the movement of the transversely movable table l2, 9. pair of dogs M5 and 2 i6 are carried by the transversely movable slide l2. As shown diagrammatically in Fig. 2, the dogs 2I5 and HS are mounted on the stop sleeve I08. These dogs are arranged to engage an arm 2" of a bell crank lever 2l8. The bell crank lever 2"! is pivotally supported on a shaft 2|9. The short arm of the bell crank 2S8 is connected by a link 220 with the lever 30. It will be readily apparent from the foregoing disclosure that when the transversely movable slide l2 moves transversely to a predetermined position in either direction, the bell crank lever 218 will be rocked by one of the dogs 2 I5 or 216 to shift the cycle control lever 30 into a reverse position, thus shifting the control valve 25 so as to start the movement of the work table II.

In actual construction, as illustrated in Figs. 5, 6, 'l and 8. the dogs M5 and 2l5 carried ly the transversely movable table l2 serve to rock the lever 30 to rock the shaft 38. Rotary motion oftransversely movable table l2. The dog 2l6 is adlustably mounted on a pivotally mounted 0011'? trollever 2|6a which is pivotally supported by a stud 21Gb on the dog H5. The control lever 2I6a is normally held in an operative position (Fig. 6) byjmeans of a spring 2l0c. If it is desired to traverse the table I 2 toward the right (Fig. 6) beyond the normal stroke, the. lever 2160. may be moved in a clockwise direction to raise the dog 2|6 to an inoperative position out of the path of the stud 2" on the lever 39.

' Interlock-work index It is desirable to provide a suitable interlock to prevent indexing of the work piece It when the work piece is in an operative position relative to the grinding wheels l6 and II. This interlock preferably comprises an adjustable dog 225 which is adjustably mounted on the front edge of the longitudinally movable table II. The dog 225 is provided with a lower plane surface 226. The lever I05 is provided with a roller 22'! which is positioned so that when the lever I05 is in an inoperative position. the roller l2! will ride beneath the surface 226 of the dog 225. When the roller 22'! is positioned beneath the surface 226, it serves as a stop to prevent shifting of the index control lever in a counterclockwise direction so as to prevent initiating an indexing movement of the work piece l8 except when the table II is in an extreme left-hand end or loading position. When the table I I is moved to its left-hand end or loading position, the dog 225 moves out of the path of the roller 22'! so that the lever I05 may be readily shifted in a counterclockwise direction to index the work piece in the manner above described.

Truiny apparatus It is desirable that a suitable truing apparatus be provided so that the opposed faces of the grinding wheels l6 and I? may be simultaneously trued to the desired and predetermined extent. It is desirable to provide a truing mechanism in which the truing diamonds are fixed during the normal operation of the machine so that after the wheels have been trued, it is not necessary to reset the feeding mechanism before resuming the grinding operation. The diamonds are adjustable only to compensate for wear of the diamond itself. In the grinding operation illustrated in the present case, it is desirable to have the operative faces of the grinding wheels back tapered toward the center in a manner such as that diagrammatically shown in Fig. 14. A

pair of truing tools or diamonds 230 and 23l are provided to true the operative faces of the grinding wheels l6 and I1, respectively. These diamonds are mounted in a manner to be herein after described and are arranged to traverse in a direction such as illustrated by the line 232 in the diagrammatic illustration in Fig. 14. This line 232 is parallel to the face of the wheel IE to be trued by the diamond 230 and is also parallel to the face of thegrinding wheel I! to be trued by the diamond 23].

This truing mechanism has been illustrated in Figs. 11, 12, 13 and 14. A frame 234 is fastened to the column l3 of the machine. This frame 234 serves as a, support for a plate 235. The plate 235 is arranged to pivot on a stud 235 and may be clamped in adjusted position on the frame 234 bymeans of clamping screws 23'! and 238. The clamping screws 23'! and 238 pass through elongated slots 233 and 240 formed in the plate 235. It will be readily apparent from the foregoing disclosure that the plate 235 which serves as a support for the truing apparatus may be angularly adjusted to determine the path of movement of the

truing tools

230 and 23!.

The plate 235 is provided with a pair of spaced

bearing brackets

2 and 242. The bearing bracket 24I rotatably supports a longitudinally extending sleeve 243 (Fig. 12). is rotatably supported'within a sleeve 244 which is journalled in a bearing surface formed in the bracket 242. The sleeve 243 is provided with an adjustabiy mounted truing tool arm 245 which serves as a support for the truing tool 23I. The sleeve 244 is provided with a truing tool arm 248 which serves as a support for the truing tool 238.

In order to traverse the truing tools 238 and 23I across the operative faces of the grinding wheels I8 and II respectively, a suitable traverse mechanism is provided comprising a hand wheel 241 which is mounted on the outer end of a feed screw shaft 248 having a feed screw 249 formed at its left-hand end (Fig. 11). The feed screw The sleeve 243 justing knob 288 isprovided for adjusting the arm 252.

when it is desired to true the grinding wheels. the operator adjusts the position of the feed stop control wheels 283 and 2I8, respectively, by an amount equal to the amount it is desired to true off the faces of the grinding wheels. After this adjustment has been made, the hand wheel 241 is rotated to traverse the truing tools 238 and 23I across the operative faces of the grinding wheels I8 and II, respectively, to true the operative faces thereof. The diamonds 238 and 23I are not ad- 249 is screw threaded into a nut 258- which is fixedly mounted relative to the plate 235 and the bracket 24I. It will be readily apparent from the foregoing disclosure that rotary motion of the hand wheel-24'! will be imparted through the feed screw 249 and the nut 258 to traverse the

sleeves

243 and 244 longitudinally relative to the plate 235 so as to impart a traversing movement to the truing tools 238 and 23I to traverse the same across the operative faces of the grinding wheels I8 and II, respectively.

In order to facilitate adjustment of the

truing tools

238 and 23! to compensate for diamond wear, an arm 25I is fixedly mounted on the righthand end of the sleeve 243. An arm 252 is fixedly mounted on the right-hand end of the sleeve 244.

The arms 25I and 252 are substantially identical in shape and are arranged to facilitate angular adjustment of the

sleeves

243 and 244, re-

ju'sted during use of the machine except to compensate for wear on the diamonds themselves.

A one-shot lubricant pump 285 (Fig. 2) is provided to convey lubricant to thewheel slldeway and to the work table ways. A manually operable knob 288 is provided for manually actuating the one-shot pump 285 when desired. If desired, the one-shot pump 285 may be actuated in timed relation with the operating mechanisms of the machine. As ,illustrated in the drawings. the pump 285 is actuated in timed relationship'with the work indexing mechanism so as automatically to convey a shot of lubricant through a pipe 292 and through

pipes

293 and 294 to the wheel slide and work table ways respectively (as illustrated diagrammatically in Fig. 2) each time the work index mechanism is actuated. A pipe 281 is connected at one end with the pipe I48. The other end of the pipe 281 is connected to conveyfluid under pressure to a cylinder chamber 288 in a cylinder 289. A piston 298 is slidably mounted in the cylinder 289 and is formed integral with ing screw 258 to facilitate manual-adjustment thereof. The screw 258 passes through an apercollar 28I is mounted on the screw 258 and bears against a plane surface milled on the side of the rod 253. A thrust collar 282 is slidably mounted on the outer end of the adjusting screw 258 to facilitate manual adjustment thereof. A compression spring 283 is interposed between the thrust collar 282 and the left-hand inner face of the aperture 254 of the arm 25I. It will be readily apparent from the foregoing disclosure that a rotary adjustment of the knob 259 will be transmitted. angularly to adjust the arm 25I relative to the fixed rod 253 to adjust the position of the diamond 23I which trues the lower wheel Il. The knob 259 is provided with graduations 284 and an index mark 285 is fixedly mounted on the arm 25I to-facilitate precise adjustment of the diamond 23I in setting up the machine and also to compensate for wear of the diamond 23I.

A similar adjusting screw (not shown) is provided for adjusting the arm 252 relative to the fixed rod 253. The details of this adjustment have not been illustrated since this mechanism is identical with that shown in connection with the arm '25I above described. A graduated ada stem 29I which connects the knob 288 with the one-shot pump 285. It will be readily' apparent from the foregoing description that when the lever. I85 is shifted to actuate the control valve ing machine will be readily apparent from the foregoing disclosure. Assuming all of the parts have been previously adjusted for grinding a plurality of webs I8 on a work piece I8, the work piece I8 is placed in position on the work holder which is carried by the transversely movable table I2 and is clamped in position thereon by means of a clamping nut 218. The stop and startlever 41 is then shifted into the position illustrated in Fig. 2 to render the manual traverse wheels "8 and I88 inoperative and to render'th'e hydraulic system operative. lever 38 may then be shifted in a clockwise direction to initiate a grinding cycle. This movement of the cycle control level 38 shifts the valve 25 toward the right (Fig. 2) to pass fluid under pressure into the cylinder chamber II9 to cause the table I I to move longitudinally toward'the right so as to feed the work piece into grindingrelation with the grinding wheel I8. This movement of the work table II continues until the work piece moves so that the grinding wheel I 8 is positioned as shown diagrammatically in Fig. 7 in position "in. When the work piece approaches this position. the table dog I5I,'through the roller I58, closes the slow-down valve I48 to slow down the feeding movement of the table II. At the The cycle control same time, the table dog 69 engages and shifts the control lever 62 in a clockwise direction to shift the valve 51 toward the right. The table movement serves to shift the lever 62 until the arrow point 64 passes-the high point on the roller 65, after which the released compression of the spring-pressed roller 65 quickly throws the valve 51 into the reverse position. By this time the stop sleeve I91 has engaged the fixed stop, that is, the end cap on the left-hand end of the cylinder 20 which limits the longitudinal movement of the table H toward the right.

when the valve assumes its right-hand end position, fluid under pressure is passed through pipe I3I into cylinder chamber I30 to start the movement of the transversely movable table I2 toward the rear of the machine so as to traverse the web I9 transversely relative to the grinding wheel I6 to grind the upper plane surface of the web I9 to the desired and predetermined extent. This grinding stroke continues until the stop sleeve I98 engages the cylinder cap at the lower end of the cylinder 52 (Fig, 2) which positively limits the transverse grinding feed. As the table 52 reaches the rearward end of its stroke, the dog 2I5 carried by the table I2 engages the arm 2H and rocks the bell crank lever 2 I8 in a counterclockwise direction, which movement serves through the link 220 to shift the cycle control lever 30 in a counterclockwise direction into the position shown in Fig. 2 so that fluid under pressure will pass through the pipe II'I into the cylinder chamber H8 of the cylinder 26 to start the table II moving in a direction toward the left (Fig. 2). The transverse movement of the slide I2 toward the rear is a relatively slow movement due to the fact that fluid exhausts from the cylinder chamber I29 through the needle valve I68 which controls the rate of movement thereof.

As the table II starts its movement toward the left, it is desirable that the initial movement thereof, until the work has moved clear of the grinding wheel I6, be at a slow grinding speed. This is preferably accomplished by allowing the fluid exhausting through the pipe I20 to pass through the throttle valve L57, as previously described, to produce a slow grinding feed of the table II toward the left. After the roller I5I rides oi! the lower flat face I550 of the'dog I5I, the released compression of the spring will shift the slow-down valve I48 upwardly into the position shown in Fig. 2, after which fluid may exhaust at a substantially unrestricted rate through pipe I54 instead of through the throttle valve I51 so that the table II moves at a rapid rate durin the remainder of its longitudinal'movement toward the left. The table moves toward the left until the dog I52 again depresses the roller I50 which-serves again to close the slow-down valve 8, thuscutting oi! exhaust of fluid from the cylinder to stop the table at its left-hand end position. At the same time, the dog 69a engages the lever 62 and rocks it into the position illustrated in Fig. 2 to shift the valve 51 into its extreme left-hand end position so that fluid under pressure will pass through pipes I21 and I28 into cylinder chamber I29 to move the table I2 transversely toward the front of the machine at a rapid rate so that the work piece returns to its initial or starting position, thus completing a grinding cycle. After the completion of a cycle, the position of the grinding wheel may be ad- Justed if desired. The grinding cycle may continue to be repeated automatically until interrupted manually in a manner to be hereinafter described.

When it is desired to interrupt the grinding cycle, after the work piece'has repeated the desired number of cycles as above described, a trip lever 280 (Fig. 2) is provided which serves to swing the dog 2I6 out of the path of the arm 2" of the bell crank lever 2I8 so that the table II may move to its extreme forward position. The lever 28I may then be actuated to open the slow down valve I48 to allow unrestricted exhaust of fluid from the cylinder 20 so that the table II will traverse rapidly toward the left to a loading position. In this position, the index control lever I05 may be shifted in a counterclockwise direction to index the work piece I8 through ninety degrees to present the next web IS in operative relation for a grinding operation. The grinding cycle may then be continued on successive webs until the upper plane surfaces have all been ground to the desired and predetermined extent. After the lever 280 has been tripped to render the dog 2I6 inoperative, a lever 28I is also moved in a clockwise direction to raise the valve stem I49 so that fluid may pass through to the cylinder 20 to cause a rapid movement of the table II into its loading position.

When it is desired to adjust the position of the wheels I 6 and I1, that is, the stop position thereof, to compensate for wheel wear or for a trulng operation, it is merely necessary for the operator manually to adjust the hand wheels 203, and 2III, respectively. If these adjustments are made for a truing operation, the truing tools may be traversed longitudinally by a rotary motion of the hand wheel 24! to transmit a traversing movement of the diamonds 230 and 23I so as to traverse them across the operative faces of the grinding wheels I6 and II, respectively.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a base, a wheel slide thereon, a rotatable spindle on said slide, a pair of spaced grinding wheels on said spindle having opposed operative faces which are arranged successively to grind opposed plane faces on a work piece, means including a piston and cylinder to move said slide successively to position the grinding wheel faces in operative positions, and a pair of independent micrometer adjusting mechanisms to limit the movement of said slide in either direction precisely to locate the wheel faces relative to the work piece.

2. In a grinding machine having a base, a wheel slide thereon, a rotatable spindle on said slide, a pair of spaced grinding wheels on said spindle having opposed operative faces which are arranged to grind opposed plane faces on a work piece, means including a piston and cylinder to move said slide, a double end piston rod connected with said piston, connections between said rod and said slide, a pair of stop sleeves which are screw threaded on the piston rod at opposite ends of said cylinder which are arranged to engage the ends of said cylinder so as to limit ass'mu 9 I the movement of said piston and wheel slide in either direction, and an independent micrometer adjusting mechanism precisely to adjust each of i said sleeves relative to said piston rod to facilitate positioning the operative faces of the grinding wheels successively to grind opposed plane faces on a work piece.

3. In a grinding machine having a vertically movable grinding wheel slide, a rotatable grinding wheel thereon, a 'piston and cylinder to move said slide, a piston rod connecting said piston with said slide, an adjustable stop for limiting the movement of said piston in one direction, a micrometer feed mechanism for adjusting said stop, a control valve therefor, a longitudinally:

movable table, a transversely movable table on said longitudinally movable table, a piston and cylinder for said transversely movable table, a

control valve therefor, and an automatic cycle control mechanism to cause a transverse movement of said table to a predetermined position and a return thereof to its initial position so as to grind a predetermined plane face on a work piece.

4. In a grinding machine having avertically support on said transversely movable table which is arranged successively to present predetermined portions on a work piece for a grinding operation, and an automatic cycle control mechanism for said valves to cause a movementof said longitudinally movable table to a predetermined position, then a movement of said transversely movable tableto a predeterminedposition so as to grind a predetermined plane face on a work piece, after which said tables are moved to their initial positions.

7. In a grinding machine having a vertically movable grinding wheel slide, a pair of spaced rotatable grinding wheels on said slide having opposed operative faces which are arranged to grind opposed plane faces on a work piece, a

piston and cylinder to move said slide, a piston rod connecting said piston with said slide, a pair of adjustable stop sleeves on said piston rod successively to position the operative faces of said grinding wheels, a control valve therefor, a longitudinally movable table, a piston and cylinder to move said table, a control valve therefor,

Y a transversely movable table on said longitudimovable grinding wheel slide, a rotatable wheel thereon, a piston and cylinder to move said slide, a piston rod connecting said piston with said slide, an adjustable stop for limiting the movement of the piston in one direction. a micrometer feed mechanism for adjusting said stcp,,a control valve therefor, a longitudinally movable ta- .ble, a piston and cylinder to move said table,

a control valve therefor, a transversely movable table on said longitudinally movable table, a piston and cylinder to move said transversely movable table, a control valve therefor. a rotatable indexable work support on said transversely movable table, and an automatic cycle control mechanism for said valves for causing a movement of said longitudinally movable table to a predetermined position, then a movement of said transversely movable table to a predetermined position so as to grind a predetermined plane faceon a work piece.

5. In a grinding machine as claimed in claim 4. thecombination with the parts and features therein specified, of a counterbalance piston and cylinder, said counterbalance piston being connected to the wheel slide piston rod, a fluid pressure system including a fluid pump, an adjustable relief valve in said system to maintain a predetermined operating pressure in said system, a pipe to convey fluid exhausting from said relief valve into said counterbalance cylinder, and

a relief valve associated with the counterbalance cylinder to facilitate controlling the pressure in said latter cylinder so as to counterbalance the weight of the wheel slide and associated parts.

6. In a grinding machine having a vertically tudinally movable table, a piston and cylinderto move said transversely movable table, a control valve therefor, a rotatable indexable work nally movable table, a piston and cylinder to move said transversely movable table, a control valve therefor, a rotatable indexable work'support on said transversely movable table which is arranged successively to present predetermined portions on a work piece for a grinding operation, and an automatic cycle control mechanism for said valves to cause a movement of said longitudinally movable table to a predetermined position, then a movement of said transversely movable table to a predetermined position so as to grind a, predetermined plane face on a work piece, after which said tables are moved to their initial positions, said control mechanism being arranged so that the cycle of operation repeats itself until the surface of the work piece has been ground to the desired and predetermined extent. 8. In a grinding machine having a vertically movable grinding wheel slide, a pair of spaced grinding wheels thereon, a piston and cylinder to move said slide, a control valve therefor, a longitudinally movable table, a piston and cylin-- der to move said table, a control valve therefor, a manually operable control lever therefor, a transversely movable table on said longitudinally movable table, a piston and cylinder to move said transversely movable table. a control valve therefor, a control level-for said latter valve, ad-

, :Iustable dogs on said transversely movable table predetermined position, after which the transversely movable table moves transversely'to' a predetermined position to grind a plane face on the work piece and thereafter successively to return said longitudinally movable table and said transversely movable table to, their initial positions.

9. In a grinding machine as claimed in claim 8,. the combination with the parts and features therein specified, 'of a. manually operable lever,

and connections between said lever andone of the dogs on said transversely movable table to render said dog inoperative and thereby to interrupt the continuous cycle.

vl0. In a grinding machine as claimed in claim 8, the combination with the parts and features therein specified, of a manually operable lever which is operatively connected to render one of the transversely movable'table dogs inoperative so as to interrupt the continuous grinding cycle, and a second manually operable .lever which is operatively connected to shift said tables to a loading position after a predetermined grinding operation has been completed.

11. In a grinding machine having a vertically movable grinding wheel slide, a pair of spaced grinding wheels thereon, a piston and cylinder to move said slide, a control valve therefor, a longitudinally movable table, a. piston and cylinder to move said table, a control valve therefor, a manually operable control lever therefor, a transversely movable table on said longitudinally movable table, a piston and cylinder to move said transversely movable table, a control valve therefor, a control lever for said latter valve, adiustable dogs on said transversely movable table to actuate the control lever for said longitudinally movable table, and adjustable dogs on said longitudinally movable table to actuate the control lever for said transversely movable table, said dogs and levers being arranged automatically to traverse the longitudinally movable table to feed the work toward the -grinding wheel to grind a plane surface on a work piece to a predetermined extent, after which the transversely movable table is automatically traversed transversely relative to the grinding wheel to traverse the grinding wheel across a predetermined face on the work piece, thereafter automatically to traverse the longitudinally movable table to move the work piece to an inoperative position first at a. grinding rate until the work is out of grinding contact with the grinding wheel, after which the longitudinally movable table moves rapidly to a predetermined position and thereafter automatically to traverse the transversely movable table rapidly to return the work piece to its initial position.

12. In a grinding machine having a vertically movable grinding wheel slide, a pair of spaced grinding wheels thereon, a piston and cylinder to move said slide. a control valve therefor. a longitudinally movable table, a piston and cylinder to move said table, a control valve therefor, a manually operable control lever therefor, a transversely movable table on said longitudinally movable table, a piston and cylinder to move said transversely movable table, a. control valve therefor. a control lever for said latter valve, adjustable dogs on said transversely movable table to actuate the control lever for said longitud naliy movable table, and adjustable do s on said lon itudinally movable table to actuate the control lever for said transversely movable table, said dogs and levers being arranged automatically to traverse the longitudinally movable table to feed the work toward the grinding wheel at a grinding rate to grind a plane surface on a work piece to a predetermined extent, after which the transversely movable table is automatically traversed transversely relative to the grinding piece to an inoperative position first at-a grinding rate until the work is out of grinding contact with the grinding wheel, after which the longitudinally movable table moves rapidly to a pre-. determined position and thereafter automatically to traverse the transversely movable table rapidly to return the work piece to its initial position.

13. In a grinding machine as claimed in claim 4, the combination with the parts and features therein specified, of a work index mechanism including an index plate, a holding pawl to locate said plate and work piece in a predetermined position for a grinding operation, a. pivotally mounted actuating pawl associated with said indexing plate, a piston and cylinder to actuate said latter pawlto index said work piece successively to present predetermined portions of the work piece into grinding positions, a control valve therefor, a manually operable control lever to actuate said valve, and an interlock to prevent movement of said control lever except when the work table is in an inoperative or loading position.

14. In a grinding machine as claimed in claim 4, the combination with the parts and features therein specified, of a work indexing mechanism including an index plate, a holding pawl to locate said plate and work piece in a predetermined position for grinding, a pivotally mounted actuating pawl associated with said index plate, a piston and cylinder to actuate said latter pawl to index said work piece successively to present predetermined portions of the work piece into grinding positions, a control valve therefor, a manually operable control lever to actuate said valve, and an interlock including anadjustable dog on said longitudinally movable table to prevent movement of said control lever to initiate an indexing movement of the work piece except when the longitudinally movable table is in an inoperative or loading position.

15. In agrinding machine as claimed in claim 4, the combination with the parts and features therein specified, of a lubricating system for the wheel slide and work table ways, including a oneshot lubricant pump, manual means to actuate said pump, a piston and cylinder to actuate said pump, operative connections between said work index control valve and said cylinder whereby fluid under pressure is admitted simultaneously to the work index cylinder and to the lubricant pump cylinder to actuate said lubricant pump each time the work indexing mechanism is actuated to convey lubricant to the wheel slide and table ways.

16. In a grinding machine as claimed in claim 4, the combination with the parts and features therein specified, of a slow-down valve in the wheel at a grinding rate to allow the grinding wheel to grind a predeterm ned face on the work piece, thereafter automatically to traverse the longitudinally movable table to move the work exhaust side of said longitudinally movable table cylinder, said valve normally being positioned to allow substantially unrestricted exhaust of fluid from either end of said table cylinder, said valve in a second position being arranged to reduce the exhaust of fluid from one end of the cylinder so as to change the rate of movement of said table from a rapid approaching to a grinding feed, and means including an adjustable dog on said longitudinally movable table to actuate said valve as the work piece approaches operative engagement with the grinding wheel to change the rate of movement of the table to a grinding speed.

HERBERT A. SILVER.