US2296064A - Surface grinding machine - Google Patents

Description

Sept. 15, 1942. H,-A. SILVEN SURFACE GRINDING MACHINE Eiled oct. 14, 1941 G-Sheets-Sheet 1 Illllll IIIIIIII I I jmm 'HERBERT A. SILVEN Sept. 15, 1942.

H. A. YSILVEN 23 SURFACE GRINDING mourns Filed 005. 14, 1941 6 Sheets-Sheet 2 NDING HEEL RAISED 20a 'HANII TRUINGEXHAU HEREERTQA. SILVEN Mbbdim M Sept: 15, 1942. v H. A. SILVEN 2,296,054

SURFACE GRINDING MACHINE Filed Oct. 14, 1941 S S heeiS-Sheet s I II I I II 275 1 1 2 2 274 1 52 2 g 2 2 7 g i 264 I' I 260 I I I 263 266 267 I 277 272 I 270 i 706 A 77/ HERBERT A. SIVLVEN mm.earm

Sept. 15, 1942. H. A. slum I 2,296,0

SURFACE GRINDING MACHINE 7 Filed Oct. 14, 1941 6 Sheets-Sheet 4 HERBERT A.-Su- 'vE/v Sept. 15, 1942.

H. A. SILVEN 2,296,064

SURFACE GRINDING MACHINE v v Filed Oct. 14, 1941 s S hee ts-Sheet s I44 I I 7F I lq I'll 72 E [64 I56 v. %55

{40 357 Fi Jrw vtoL HERBERT A. 5M-.VEN 145 40 F7s.5 ,%,.uumm W Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE SURFACE GRINDING MACHINE Herbert A. Silven, Worcester, Mass., assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Application October 14, 1941, Serial No. 414,946

8 Claims. (01. 51-45) The invention relates to grinding machines, and more particularly to a hydraulically operated surface grinding machine.

One object of the invention is to provide a thoroughly practical hydraulically controlled,

surface grinding machine. A further object of the invention is to provide a hydraulic surface grinding machine with a duplex fluid pump system which is arranged and controlled so that during table reciprocation both pumps supply fluid to the table cylinder. A further object of the invention is to provide a hydraulic control for a surface grinding machine having a duplex pump system, in which both pumps are automatically connected to reciprocate the table but during reversal one of the pumps is automatically connected to provide a transverse indexing movement of the grinding Wheel.

Another object of the invention is to provide a fluid pressure controlled system for a surface grinding machine, in which the pressure within the system is automatically reduced substantially to zero when the machine is stopped in a loading position. Other objects willbe in part obvious or in part pointed out hereinafter.

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

In the accompanying drawings in which is illustrated one of many possible embodiments of the mechanical features of this invention:

Fig. 1 is a front elevation of a surface grinding machine embodying the invention, showing some of the interior mechanism in dotted lines;

Fig. 2 is a fluid pressure diagram for the machine;

Fig. 3 is a. vertical sectional view, on an enlarged scale, of the venting relief valve;

Fig. 4 is a fragmentary plan View, on an enlarged scale, of the table reversing mechanism, showing the stop and start valve in section and also showing the manually operable traverse mechanism;

Fig. 5 is a fragmentary front elevation, on an enlarged scale, partly in section, of the reciproeatory traverse control mechanism and also the manually operable traverse mechanism;

Fig. 6 is a fragmentary vertical cross sectional view, taken approximately on the line 6-5 of Fig. 5; I

Fig. 7 is a fragmentary horizontal sectional view taken approximately on the line l! of Fig. 6;

Fig. 8 is a fragmentary vertical cross sectional View taken approximately on the line 8-8 of Fig. 5;

Fig. 9 is a fragmentary horizontal cross sectional View, on an enlarged scale, taken approximately on the line 9-9 of Figs. 5 and 8;

Fig. 10 is a fragmentary vertical cross sectional view taken approximately on the line Ill-40 of Fig. 8;

Fig. 11 is a fragmentary horizontal cross sectional View taken approximately on the line Il|l of Fig. 8;

Fig. 12 is a fragmentary front elevation similar to Fig, 5, showing the table dogs and the venting control valve in a tripped position at the loading station;

Fig. 13 is a fragmentary View, on an enlarged scale, taken approximately on the line l3-|3 of Fig. 12, showing the latch for the venting control valve;

Fig. 141s a fragmentary front elevation, on an enlarged scale, showing the table dogs and parts as positioned when the table is in the center of its reciproeatory grinding stroke;

Fig. 15 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line l5-l5 of Fig. 14;

Fig. 16 is a fragmentary front elevation, on an enlarged scale, of the table dogs and associated parts, showing the right-hand reversing roller depressed to allow the table to move to a loading position;

Fig. 17 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line l'l-l'l of Fig. 16;

Fig, 18 is a fragmentary sectional View, on an enlarged scale, taken approximately on the line l8--l8 of Fig. 16;

Fig. 19 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line l9l9 of Fig. 1, illustrating the feeding mechanism for feeding the grinding wheel in a vertical direction;

Fig. 20 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line 20-20 of Fig. 19;

Fig. 21 is a fragmentary sectional View, on an 7 Fig. 23 is a fragmentary sectional view, on an enlarged scale, taken approximately on the line 23-23 of Fig. 21, through a portion of the feed clutch.

A surface grinding machine has been illustrated in the drawings comprising a base 40 which supports a longitudinally reciprocable work supporting table 4| on the usual V-way 42 and flat way 43 formed on the upper surface of the base 40. The base 40 supports an upwardly projecting massive column 46 (Fig. 1) which is provided with a vertically extending slideway 41. A vertically movable slide 48 is provided with Ways which mate with the slideway 41 so that the slide 48 may be moved and adjusted in a vertical direction. The vertically movable slide 48 is provided with a horizontally extending slideway 49 which serves as 'a support for a transversely movable wheel slide In the preferred form an anti-friction support is provided for the wheel slide 56 which may comprise a plurality of anti-friction rollers 5| (only one of which is shown in Fig. 1) which are arranged at opposite ends of the wheel slide 59 and are each supported thereon by means of a shaft 53. The rollers 5| ride upon the slideway 49 and serve as an antifriction support for the wheel slide '50.

The cross slide or wheel slide 50 serves as a support for a rotatable grinding wheel 55 which is supported at one end of a rotatable grinding wheel spindle 56. The wheel spindle 56 is journalled in suitable bearings (not shown) which are mounted in fixed relation with the wheel slide 53. The wheel spindle 56 may be driven by means of an electric motor 51 which is adjustably supported on a bracket depending from the wheel slide 50 (Fig. l). The motor 51 is provided with a multiple V-groove pulley 58 which is connected by means of a multiple V-belt 59 with a multiple V-groove pulley 60 which is mounted on the end of the wheel spindle 56.

Hand table traverse If desired, the work supporting table 4| may be traversed longitudinally by means of a manually operable traversing mechanism (Figs. 1, 4 and 5) comprising a rack bar 62 which extends longitudinally of and is fixedly mounted on the under side of the table 4 l A gear 63 is mounted on the inner end of a rotatable shaft '64 which is journalled in suitable anti-friction bearings (not shown) which are supported within a slidably mounted sleeve 61 keyed within an aperture 68 formed integral with an apron 69 fixedly mounted on the front of the machine base 49. A gear is keyed on the end of the shaft 64 (Figs. 4 and 5). The gear 10 meshes with a gear 1| which is rotatably supported on a shaft 12. The stud I2 is fixedly mounted relative to the apron 69. A manually operable traverse wheel 13 is supported to rotate with the gear The sleeve 6! is arranged for an axial sliding movement so that the gear '63 may be readily moved into or out of mesh with the rack bar 62. As illustrated in Figs. 4 and 19, the gear 63 is shown out of mesh with the rack bar 62 and is held in this position by means of a spring-pressed detent 14 (Fig. 4) carried by the apron 69 which engages'a V-shaped notch l5 cut in the periphery of the sleeve 61. When it is desired to traverse the table 4| manually, the sleeve 61 is moved upwardly (Fig. 4) to shift the gear 63'from the full line position into the dotted line position 63a in mesh with the rack bar 62, in' which position a second V-notch 16 formed on the sleeve 87 is moved into engagement with the detent 14 to hold the sleeve 51 in an operative position.

During the normal grinding operation the table 4| is preferably traversed or reciprocated longitudinally by a hydraulically operated mechanism to be hereinafter described, and a hand traverse mechanism is maintained in an inoperative condition, as shown in Fig. 4, with the gear 63 out of mesh with the rack bar 82. The manual traverse mechanism, as above described, is preferably interlocked with the hydraulic table traverse mechanism so that the manual traverse mechanism is locked in an inoperative position during the power traverse of the table 4|,

Hydraulic table traverse mechanism The work table 4| is traversed or reciprocated longitudinally by means of a hydraulically operated table traverse mechanism comprising a pair of spaced parallel cylinders and 8| (Fig. 2). The cylinders 80 and 8| are fixedly mounted relative to the base 4|]. The cylinder 88 contains a slidably mounted piston 82 which is connected. by means of a piston rod 83 with a bracket 84 depending from the under side of the table 4| at its right-hand end (Fig. 2). Similarly, the cylinder 8| contains a slidably mounted piston 85 which is connected by means of a piston rod 86 with a'bracket 81 depending from the under side of the table 4| at its left-hand end.

A table reversing valve 96 is provided to control the passage of fluid under pressure through a pipe 9| into a cylinder chamber 92 within the cylinder 8|, or through a pipe 93 into a cylinder chamber 94 formed within the table cylinder 80. The reversing valve 9|! is a piston type reversing valve comprising a valve stem 95 having formed integrally therewith the valve pistons 96, 91, 98, 99, 00 and HM.

A fluid pressure system is provided for conveying fluid under pressure to the various mechanisms of the machine, comprising a reservoir I02 (Figs. 1 and 2) which is preferably formed within the box-like base 40 of the grinding machine. A motor |U9 drives a duplex fluid pressure pump comprising two independent fluid pressure pumps H13 and I94. The pump I03 is of a relatively large capacity and the pump Hi4 is of a relatively small capacity. The pump I03 draws fluid through a pipe I65 from the reservoir Hi2 and forces fluid under pressure through a pipe I06 (Fig. 19) which is connected to admit fluid under pressure to a valve chamber Hi! located between the valve pistons 91 and 93 and also to a valve chamber "I98 located between the valve pistons 99 and I00. Fluid under pressure entering the valve chambers W1 and I08, respectively, depending upon the position of the valve stem 95, 'isadmitted either through the pipe 9| into the-cylinder chamber 92 to cause the table 4| to move toward the right or is passed from the chamber I68, through the pipe 93, into the cylinder chamber 94 to cause the table 4| to move toward the left. The capacity of the pump I03 is utilized only to cause a reciprocatory or traversing movement of the Work supporting table 4|.

The smaller capacity pump H34 draws fluid from the reservoir I02, through a pipe H0, and forces fluid under pressure through a pipe Ill and a pipe ||2 (Fig. 19) to the ends of the table reversing valve 90. Fluid under pressure passing through the pipe H2 is also conveyed through a pipe H4 to a pilot valve H and through a pipe H6 to a pilot valve H1. Fluid under pressure passing through the pipe H2 is connected to supplement the capacity of the large pump I03 1 and passes into the table cylinders M or 89, respectively, to supplement the power supplied by the larger capacity pump I03 during the table traversing movement. Fluid under pressure passing through the pipes or passages H4 and H6 in the end caps of the reversing valve 90 (Fig. 19) into the pilot valves H5 and I I1, respectively, serves during table reversal to shift the reversing valve 90 into its reverse position.

Fluid under pressure passing through the pipes III and II 2 also passes .through a manually operable reverse valve I I8, a shuttle type pilot valve H9, and a control valve I20 to one end or the other of a wheel slide indexing cylinder I2I The exhaust of fluid from the grinding wheel indexing cylinder I2I is controlled by a stop and start valve I22 which controls the exhaust of fluid into a metering valve I23. The metering valve I23 serves to allow a predetermined quantity of fluid to be metered or exhausted from the cylinder I 2| so as to facilitate a predetermined transverse indexing movement of the grinding wheel 55 and its supporting wheel slide 55. Fluid under pressure from the-small capacity pump I54 passing through the pipes III and H2 enters a control valve I24 which is opened during table reversal to pass fluid under pressure through a pipe I25 to actuate the stop and start valve I22 so as to allow the exhaust of fluid from the table indexing cylinder I2I in timed relationship with the reversal of the work table M,

It will thus be seen that the smaller capacity pump I04 has four distinct functions, namely, to supplement the large capacity pump I03 during the longitudinal reciprocatory movement of the table 4|, to shift the table reversing valve 00 into its reverse position at table reversal to sup-ply fluid under pressure at all times either to one side or the other of the wheel slide indexing cylinder I2I, and also to control the exhaust of fluid from the wheel indexing cylinder I2I so as to index the grinding wheel 55 transversely during reversal of the work supporting table 4i.

The pipe III conveying fluid under pressure from the small capacity pump I54 passes fluid to a manually operable control valve I28 which controls the admission of fluid to a fluid motor I29 which is connected to raise or lower the wheel slide 50 so as to vary the position of the grinding wheel 55 relative to the work supporting table 4|.

Reverse oaZve-Actuating mechanism A reversing lever I (Figs. 1, 4 and 5) is mounted on the front of the machine base. The lever I35 is formed as a bell crank lever having oppositely projecting arms I33 and I 31 which serve as supports for rotatably mounted rollers I38 and I39. The reversing lever I35 is fixedly mounted on the upper end of a rock shaft I40. The rock shaft I40 is arranged in a substantially vertical position and is supported in bearings MI and I42. The bearings HH and I42 are in turn supported in a hollow rotatable sleeve I 43 which is in turn rotatably supported within an aperture I44 formed within a table reversing apron I45 whch is fixedly mounted on the front of the machine base 40.

The roller I38 is rotatably mounted on the instantaneously upper end of a stud I46 which is fixedly mounted relative to the reversing lever arm I36. The roller I38 is arranged in the path of a cam face I41 formed on a table dog I48 which is adjustably supported by means of a T-slot I49 formed in the front edge of the work supporting table M. The roller I39 is rotatably mounted on the upper end of a vertically movable stud I50 which is slidably supported within an aperture adjacent to the end of the arm I31 of the reversing lever I35. The roller I 39 is shown in its lower position, in which position it lies in the path of a cam face I5I formed on a table dog :52 which stops the table movement toward the left (Figs. 1, 5 and 12) after a grinding operation has been completed, to facilitate a loading operation. When the grinding cycle is started, the roller I39 is moved upwardly into the position (Fig. 14), in which position the roller I39 lies in the path of a cam I53 formed on a table dog I54. It should be noted that the cam face I41 of the dog I48 and the cam face I53 of the dog I54 are arranged in different horizontal planes so that there is no conflict between the actuating rollers I38 and I39, respectively.

A lever I 55 is adjustably fixed to the lower end of the rock shaft I40 (Fig. 6). The other end of the lever I55 supports a shoe I56 which is operatively connected in a manner to be hereinafter described to actuate'the reversing valve 90.

A load and fire mechanism is'provided for rapidly shifting the pilot valves H5 and H1 in opposite directions. The load and fire mechanism, as illustrated, may comprise an arrow-pointed, spring-pressed plunger I51 supported in the apron I45 which is arranged to engage a roller I58 which is in turn rotatably supported by a stud I59 carried by the lever I55 (Figs. 6 and '1). It will be readily apparent from the foregoing disclosure that when the table 4E approaches either end of its stroke, either the table dog I48 or I54 will rock the reversing lever I35 to rock the rock shaft I40 so as to rock the lever I55. During the initial rocking movement of the lever I55, the roller I58 will ride up one side of the arrow-pointed plunger I51 to compress the spring. After the roller I58-rides over the high point of the arrow point I51, the released compression of the spring will rapidly shift the arm I55 together with the rod I64 to shift the pilot valves H5 and H1 into a reverse position.

The reversing valve is provided with a pair of end caps I60 and I6I which enclose the ends and are provided with downwardly projecting portions which are formed integral with the pilot valves H5 and H1. The pilot valves H5 and H1 are preferably piston type valves having slidably mounted pistons I62 and I83, respectively. The valve pistons I62 and I63 are interconnected by means of a slidably mounted rod I64 which is arranged so that the pilot valves may be simultaneously shifted by movement of the rod I64. A pair of stop collars I65 and J66 are fixedly mounted on the rod I64 and serve to limit its endwise movement. A spool I61 is fixedly mounted on the rod I64 (Fig. 2). The spool I61 is provided on its under side with a groove which mates with an upwardly extending portion of the shoe I56. It will be readily apparent from the foregoing disclosure that when the table dogs I48 and I54, through the reversing lever I35, rock the shaft I40, the rocking motion will be transmitted through the lever I55 and the shoe I56 to produce an endwise movement of the rod I64 so as to shift the pilot valves H5 and H1 to reverse the position of the reversing valve 90.

A passage I68 is provided in the end cap I60 to connect the pilot valve II 5 with an end chamber I99 formed at the left-hand end of the reversing valve 90. In the position of the pilot valve II5, fluid under pressure from the small capacity pump I04 passes through the pipe IM, through the pilot valve I I5, the passage I08, into the end chamber I69 to move the reversing valve stem 95 toward the right into the position shown in Fig. 2. A pipe I is connected between the pilot valve H5 and the reservoir I02 to facilitate exhaust of fluid from the end chamber I69 when the pilot valve H5 is shifted into the reverse position.

Similarly, a passage III is provided in the end cap I6! to connect the pilot valve II? with an end chamber I12 formed at the right-hand end of the reversing valve 90. In the position of the valve 90 shown in Fig. 2, the end chamber H2 and passage Ill are connected through the pilot valve III with an exhaust pipe IE3 so that fluid within the chamber I'I2 may readily exhaust into the reservoir I02.

When the table 4i reaches the other end of its reciprocatory stroke, the table dogs I48 and I54 are arranged to rock the reversing lever I35, the rock shaft I40, and the lever I95 to move the rod Hi4 toward the left (Fig. 2) simultaneously to move the pilot valves I I5 and I II toward the left, which movement serves to admit fluid under pressure from the pipe II6, through the pilot valve I I7, the passage III, into the end chamber I'I2 to move the valve stem 95 into its reverse position. During this movement of the reversing valve 90, fluid within the chamber I69 may exhaust through the passage I68, the pilot valve H5, and the pipe I'I0, into the reservoir I02. The exhaust pipes I10 and I73 are connected to a common exhaust pipe I74 which passes exhaust fluid into the reservoir I02. An adjustable throttle valve I'I5 is provided in the exhaust pipe I'M by means of which the speed of shifting movement of the reversing valve 90 under the influence of fluid under pressure may be accurately and precisely controlled to obtain the desired table reversal.

The reversing lever I is normally actuated automatically in timed relation with the movement of the table M to control the length of its reciprocatory stroke. If desired, in setting up the machine or for certain grinding operations, the table reversing mechanism may be manually controlled. A manually operable table control lever I80 is rotatably supported by a stud I8I (Figs. 4 and 5). fixedly mounted on the lever I80 meshes with a gear segment I83. The gear segment I83 is formed integral with the lower end of the stud I46 which is supported adjacent to the end of the arm I30. It will be readily apparent from the foregoing disclosure that when the manually operable table control lever I80 is shifted in a clockwise direction (Fig. 4) into broken line position I80a, the gear segment I82, through the gear segment I33, shifts the reversing lever I35 in a counterclockwise direction, which movement is transmitted through the rock shaft IE0 and the lever I55, manually to shift the pilot valves II5 and II? and thereby to shift the reversing valve 90 into its reverse position. By manually shifting the control lever I80 between tie full line position and the broken line position I80a (Fig. 4), the table may be manually controlled as desired.

A gear segment I82 which is Start and stop valve In order readily to control the starting and stopping of a grinding cycle, a stop and start valve I90 is provided. This valve I90 is a piston type valve comprising a valve stem I9I having formed integrally therewith valve pistons I92 and I93. A pipe I94 connecting with a valve chamber located between the valve pistons I92 and I93 (Figs. 2 and 4) is connected with the pipe 9| which connects with the cylinder chamber located between the valve pistons 91 and 98 of the reversing valve 90. A pipe I95 connects the end chamber of the stop and start valve I90 with the reservoir I02 so that any fluid within these chambers may readily exhaust into the reservoir I02. A pipe I96 is connected at one end to the chamber located between the valve pistons I92 and I93 of the stop and start valve I90 and connects with the pipe 93 (Figs. 2 and 4). A pipe or passage I97 is connected between the stop and start valve I90 at one end and at the other end with the valve chamber located between the valve pistons 98 and 99 of the reversing valve 90, so that in the position illustrated in Fig. 3 a manual traverse of the table M is facilitated by a by-passing of fluid between the cylinders and 8|.

The valve stem I9I of the stop and start valve 290 is preferably manually controlled by means of amanually operable control lever 200 (Figs. 1 and 4) mounted on the front of the machine base. The lever 200 is fixedly mounted on the upper end of the rotatable sleeve I i-3. An arm 20I is fixedly mounted adjacent to the lower end of the sleeve I93 so that the lever 200, the sleeve I53, and the arm 20I function as a bell crank lever. The arm '29I is connected by a stud 202 with one end of a link 253. The other end of the link 203 is connected by means of a stud 204 with the valve stem I9I. It will be readily apparent from the foregoing disclosure that when the lever 200 is moved in a counterclockwise direction (Fig. 4), from the full line position to the broken line position 200a, the parts will be rocked to cause an upward movement of the valve stem I9I.

A plurality of ports 205 arranged in a staggered relationship are formed in the sleeve of the stop and start valve I and serve as a speed controlling device for the table iI, whereby the exhausting fluid from the table cylinders 80 or 8| may be readily controlled to regulate the speed of the table M. In order to facilitate adjustment of the valve I90 to regulate the table speed, a stop mechanism is provided comprising a stop lug or pin 29% (Fig. 4) which is fixedly mounted to a flange or collar 29? carried by the valve stem WI. The stop pin 206 is arranged so that it moves in the path of a rotatably adjustable stop cam 203 (Fig. 4). The cam 268- is fixedly mounted on the inner end of a rotatable shaft 209 which is rotatably supported within the apron I45. An actuating knob 2I0 is mounted on the outer end of the camshaft 209 and is arranged so as to facilitate adjustment of the cam 208 to determine and adjust the speed of movement of the table M. This mechanism has not been illustrated in detail in the present application, since it is not considered to be a part of the present invention. This speed adjusting mechanism is fully shown and described in my prior U. S. pending application Serial No. 326,224 filed March 2'7, 1940.

Interlock-Hand and hydraulic table traverse It is desirable to provide an interlocking mechanism between the manually operable mechanism and the hydraulically operated table reciprocating mechanism so that the hydraulic movement of the table 4| cannot be started unless the hand traversing mechanism is in an inoperative position. The upper end of a rock arm 2 (Fig. 4) is connected by means of a stud 2I2 with one end of a link 2I3. The other end of the link 2I3 is connected by a stud 2I4 with the link 203. An arcuate slot 2I5 (Fig. 4) is cut through the housing surrounding the cylindrical bore 68, and into the slidably mounted sleeve 61 which supports the hand traverse mechanism for movement into and out of operative position. When the hand traverse mechanism is in an inoperative position, that is, when the gear 63 is in the full line position (Fig. 4) out of mesh with the rack bar 62, the arcuate slot 2 I 5 in the sleeve 61 is aligned with the portion of the arcuate slot 2I5 through the housing surrounding the sleeve 61. In this position of the hand traverse mechanism, the manually operable stop and start lever 208 may be readily operated to actuate the stop and start valve stem I9I to start a grinding cycle.

During the rearward movement of the stop and start valve I90, the link 2I3 is moved toward the left, which movement swings the rock arm 2| I in a counterclockwise direction so that its enlarged arcuate lower portion slides out of the arcuate slot 2 I5. The hand traverse mechanism may be manually rendered operative by sliding the gear 63 into position 63a (Fig. 4) into mesh with the rack bar 62. If the hand traverse mechanism is in an operative position, the stop and start lever 20!! cannot be actuated due to the fact that the arcuate slot 2I5 in the sleeve 61 is out of line with the slot through the housing so that when the rock arm 2 is moved in a clockwise direction, the lower end thereof will engage the periphery of the sleeve 61 and serve as a stop to prevent shifting the stop and start valve ISO to start a grinding cycle. It will be readily apparent from the foregoing disclosure that an inter- 4 look is provided whereby the manually operable cycle stop and start valve I90 is rendered inoperative when the hand traverse mechanism is in an operative position. The hand traverse mechanism is similarly rendered inoperative when the stop and start valve is in an operative position.

Vertical feed A feeding mechanism is provided for moving the vertically movable slide 48 to adjust the position of the grinding wheel 55 relative to the work table 4| and the work piece to be ground. This mechanism has not been illustrated in detail in the present application, since it is not considered to be a part of the present invention. For details of disclosure not contained herein, reference may be had to my pending U. S. application Serial No. 326,224 filed March 27, 1940. This feeding mechanism may comprise a nut and screw feed mechanism including a rotatable feed screw 228 (Fig. l).

A manually operable mechanism is provided on the front of the machine base comprising a manually operable hand wheel 22! which is rotatably supported on a stud 222 which is in turn supported in an apron 223 on the front of the machine base 48 (Fig. 19). The hand wheel 22I is connected through a micrometer feed adjusting mechanism 224 by means of a pinion 225 with a gear 226 which is also rotatably supported on the stud 222. A gear 221 is formed integral with the gear 226' and meshes with a gear 228 which is rotatably supported on a rotatable shaft 229 which is rotatably supported in bearings 238 in the apron 223 at one end. The rotatable shaft 229 is operatively connected to rotate the vertically arranged feed screw 220. Reference may be had to my prior application for a disclosure of these driving connections. A clutch 23I is connected between the shaft 229 and the gear 228, whereby the gears may be connected to or disconnected from the shaft 228. In the position of the parts illustrated in Fig. 19, the clutch 23I is shown in engagement so that a rotary motion of the hand wheel 22I will be transmitted to rotate the shaft 229 and the feed screw 228 to cause a vertical adjustment of the vertically movable slide 48.

A fluid operated mechanism is provided to supplement the operable vertical adjustment of the grinding wheel, comprising the fluid motor I29 which is operatively connected to cause a rotary movement of the feed screw 220. The starting and stopping of the fluid motor I29 (Fig. 2) is controlled by the control valve I23. It is desirable to provide a control mechanism whereby the hand wheel 22I may be rendered inoperative during a power adjustment of the vertically movable slide 28. A yoked member 232 is pivotally supported on a stud 233. The yoke 232 is provided with a pair of opposed shoes 234 and 235 which ride within a groove 23%; formed in an integral hub of the gear 228 (Fig, 19). It will be readily apparent from the foregoing disclosure that when the yoke 232 is rocked in a clockwise direction (Fig. 19), the gear 228 will be slid out of mesh with the gear 221 and the clutch 23I will be disengaged, thus disconnecting the hand wheel 22I from the shaft 229.

A stop abutment 231 (Fig. 22) is provided on the micrometer feed adjusting mechanism 224 carried by the hand wheel 221! which is arranged to engage a slidably mounted stop 238 which is supported in a bracket fixed on the apron 223. If desired, the stop member 238 may be moved upwardly into position 238a (Fig. 22) so that it is out of the path of the stop abutment 231. When the stop 23s is in the full line position indicated in Fig. 22, it lies in the path of the stop abutment 231 and serves to limit the rotary motion of the hand wheel 22I to facilitate a downward ad-' justment of the grinding wheel 55 to a predetermined position.

A control knob 24!) is mounted on the outer end of a rotatable shaft 24!. The inner end of the shaft 2M supports a downwardly extending arm 242 which is connected by means of a stud 243 and a spool-shaped member 244 with a valve stem 245 which controls the fluid motor I29. The valve I28 is operatively connected so that the motor I29 may be rotated in either direction to cause an upward or downward movement of the Vertically movable slide 48.

It is desirable to provide a suitable interlock between the clutch actuating yoke 232 and the control valve I28. An arm 246 is formed integral with the yoke-shaped member 232 and serves as a bell crank lever. The arm 246 is provided with a stud 241 which rides on a cam 2 58 which is fixedly mounted to be rotated with the control knob 248. It will be readily apparent from the foregoing disclosure that when the knob 248 is rocked either in one direction or the other to cause a vertical adjustment of the slide 48, the rotation of the cam 248 will cause an upward movement of the stud 2.41 to rock the bell crank lever 246232 to disengage the clutch 23I so as to disconnect the hand wheel 22I from the shaft 229. The rotary motion of the knob 240 in disengaging the clutch 23I will also be transmitted through the lever 2&2, spool 244, and valve stem 245 to actuate the control valve I28 to start the fluid motor I29 in either direction, depending upon the direction of rotation of the control knob 24%].

Cross feed,Wheel slide The transversely movable wheel slide 50 is arranged so that it may be moved transversely by means of a manually operable traversing or feeding mechanism or, if desired, the grinding wheel slide 50 may be fed transversely by an intermittently incremental movement actuated by and in timed relation with the work table reciprocation to advance the grinding wheel 55 automatically at the ends of the reciprocatory stroke of the table AI. A further transverse movement is provided whereby the wheel slide 55 may be continuously moved transversely at a slow uniform rate during a grinding wheel truing operation, These various means of traversing the grinding wheel slide transversely have not been illustrated in detail since these mechanisms are identical in construction with that shown in my prior U. S, pending application, Serial No. 326,224 filed March 2'7, 1940, to which reference may be had for details, oi disclosure not contained herein.

The grinding wheel slide 55 may be traversed longitudinally by means of a hand wheel 255 which operates a rackand gear mechanism, as in my prior application. A hydraulically operated mechanism is provided whereby an intermittent eross teed may be obtained at each table reversal, or a very slow speed for truing. The selector valve I (Fig. 2) is controlled by a manually operable control knob I (Figs. 1 and 2). The selector valve I20 has been indicated in its three positions in Fig. 2. The control valve I20 shows the valve in, position to facilitate automatic transverse feeding at the ends of the table stroke. The control valve I20, as indicated in Fig. 2 as I2iIa, shows the valve positioned for a hand traversing operation, in which fluid may readily by-pass between opposite ends of the cross feed cylinder Ill. The position of the valve I20, designated I201) (Fig. 2) shows the valve positioned for producing a. slow continuous transverse movement of the. grinding wheel 55 and its supporting wheel slide during a grinding wheel truing operation.

The cross feed reverse control valve II 8 may be actuated manually by means of a control knob 2'52: (Figs. 1 and 2) whereby the fluid under pressure to the opposite ends of the shuttle type reversing: valve II9 may be shifted to reverse the direction of movement of' the fluid to and from the cross feed cylinder I2I.

In case; automatic cross feed is desired at the ends of the table stroke, a rotary type reversing plate 253 (Fig. l) is provided having a pair of adjustable dogs 254 and 255 which are operatively connected; in amanner identical with that shownin my prior pending application above referred to, automatically to shift the valve IIB after the grinding wheel has traversed transversely to the predetermined extent to reverse its direction of? traverse. These features are not considered to be apart of the present invention and, therefore, it is; not deemed necessary to illustrate the mechanisms; in detail. The operation of the hydraulically operated wheel slide has, however, been illustrated diagrammatically in Fig. 2 and the controls. therefor have been illustrated on the front; elevation of the machine shown in Fig. 1.

Pressure relief In order to conserve power and prevent undue heating of the oil due to wire drawing of the oil when the table II is stationary, a control mechanism is provided whereby the normal operating pressure within the system may be reduced to substantially zero by allowing fluid from the pressure pumps to pass substantially unrestricted back to the reservoir. As shown in Figs. 2 and 3, the pressure pipe I35 from the large capacity pump I53 is connected to a check valve 269. The check valve 255 is provided with a movable valve member 26I which is normally urged to a closed position by means of a spring 252. Similarly, the pressure pipe III from the small capacity pump I64 is operatively connected to a check valve 253 having a movable valve member 264 which is normally urged toward a closed position by means of a spring 255. The check valves 265 and 263 are connected by pipes 265 and 261, respectively, with a chamber 263' of a relief valve 210. The relief valve 210 is of a balanced pressure type, comprising a valve member 2H and a seat 212 therefor. A piston 213 is formed integral with the valve member 21!. A bleeder hole 214 passes through the piston 213 and serves to allow fluid under pressure to pass therethrough into a valve chamber 215. The valve chamber 215 is connected by means of a passage 215 with a ball check valve 211 which is normally held in a seated or closed position by means of a spring 218. An adjusting screw 219 is provided for adjusting the compression of the spring 218 as desired.

In order to reduce the pressure in the fluid system of the machine to substantially zero, a venting control is provided for relieving the pressure within the valve chamber 215. The passage 216 (Fig. 3) is connected with a passage 28!]. The passage 280 is in turn connected by a pipe 28I with a venting control valve 282. The valve 282 is a piston type valve comprising a valve stem 283 having formed integrally therewith valve pistons 284 and 285.

In the position of the parts (Figs. 2 and 3), fluid under pressure from the relief valve chamber 258 passing through the bleeder aperture 214 into the valve chamber 215 may pass out through the passage 215, the passage 288, the venting pipe 28 I, into a valve chamber 285 located between the valve pistons 284 and 285 of the venting control 232, and passes out through an exhaust pipe 281 into the reservoir I52. While the venting control valve 282 remains in the position illustrated in Fig. 2, fluid pressure is admitted from the relief valve chamber 215 so that the fluid under pressure from the pumps I03 and IE4 passing through the pipes I06 and III and through the check valves 26!] and 253, respectively, causes the relief valve piston 213 to move upwardly into the position illustrated in Fig. 3 so as to raise the relief valve 2'1I from the seat 212 so as to allow substantially the full capacity of the fluid pumps I53 and I54 to pass outwardly through an exhaust pipe 288 into the reservoir I52.

The valve 282 is normally biased to an uppermost or closed position by means of a spring 285 which is contained within an aperture formed within the valve piston 285. The valve stem 283 may be latched in a downward or venting position by means of a pivotally mounted latch 29I which is pivotally supported by a stud 252. The stud 252 is fixedly supported on the lower end of a rod 293 which is slidably journalled within an aperture 294 formed in the apron I45. Compression springs 2'95 and 29B are provided for exerting a pressure on the pivotally mounted latch 29 I tending to hold it in the position shown in Fig. 8.

It is desirable that the venting valve 282 be automatically opened when the work table 4| moves into a loading position so that the pressure within the fluid system is automatically vented when the work table comes to a stopped position. In order to accomplish this desired result, a cam 291 is adjustably fixed to the loading dog I52. A follower member 298 is fixedly mounted on the upper end of the plunger 293 and is arranged in the path of the cam 291 so that when the table 4| moves toward a loading position, the cam 291 will move the follower 298 together with the plunger 293 and latch 29I downwardly to shift the valve stem 2% of the venting control valve 282 downwardly against the compression of the spring 293.

Thus fluid within the relief valve chamber 215 I may pass through the Venting pipe 28I and the venting control valve 232 and out through the exhaust pipe 281, thus venting the system and allowing the relief valve piston 2'5'3 to move upwardly under the influence of fluid under pressure to raise the valve member 21I from the seat 212 so that substantially the full capacity of fluid under pressure from the pumps I33 and I34 may pass outwardly through the pipe 238 into the reservoir I02. This venting of the system when the table 4| is stopped in a loading position prevents wire drawing or forcing fluid through a portion of the system against unnecessary pressures.

The compression springs 295 and 235 serve normally to exert a presure tending to hold the latch 29I in an operative position, such as that shown in Fig 8. A compression spring 299 is interposed between the lower end of the plunger 293 and the valve 282, exerting an upward pressure on the plunger 293.

When it is desired to start the movement of the work supporting table 4|, it is necessary first to close the venting control valve 282. In the preferred construction, this is accomplished by movement of the table start and stop lever 235. The arm Ziil carried by the sleeve I43 is provided with an outwardly extending arm 333 which is provided with an adjustable screw sea which is arranged to swing in the path of a lug 332 which is formed integral with and projects from the latch member 29L When the ,table stop and start lever 25!] is moved in a counterclockwise direction into position ZilIJa (Fig. l), this move ment swings the screw 3!!! into position 331a (Fig. 9) to trip the latch 29!. When the latch 29I is tripped, the released compression of the spring 29! moves the valve stem 233 upwardly to close the venting control valve 232, thus preventing escape of fluid under pressure from the chamber 215 of the relief valve 213. As the pressure passes through the bleeder hole 214 into the chamber 215 of the relief valve 213, the pressure on opposite sides of the pistons 21.3 equalize and together with the compression of the spring contained within the upper portion of the piston 213 causes a downward movement of the piston to move the valve member 21I into engagement with its seat 212, thus closing the relief valve 213. As the pressures become equalized, the check valve members 25] and 254 are automatically closed due to the compression of the springs 232 and 265, respectively, combined with the equalized pressure within the spring chambers. The control lever 230 may then be moved from position 250a into full line position 233 (Fig. 4), which pressure on the stud I53.

movement serves again to open the stop and start valve I99 to start the movement of the table 4|.

After a predetermined grinding operation has been completed, the roller I33 carried by the arm I31 of the reversing lever I35 may be manually depressed out of the path of the cam I53 so that on the next table stroke toward the left, the dog I54 and the cam I53 will pass by the roller I 39 so that the roller I39 lies in the path of the cam I5I of the dog I52 to rock the reversing lever I35 to reverse the table reversing valve 9!]. The stud I50 supporting the roller I39 is arranged for a vertical movement. The lower end of the stud I53 is pinned to a slidably mounted sleeve 335 which is slidably mounted within the arm I31. A pin 336 passes through the sleeve 335 and its projecting end is arranged to slide within a slot 331 formed in the lever I31. A slidably mounted plunger 308 is supported in the lower end of the sleeve 305. The pin 336 passes through an elongated slot formed in the plunger 338. tween the stud I50 and the upper portion of the stud 338 and serves normally to exert an upward The lower end of the stud 338 slidesupon the upper surface of the cam follower member 298.

When it is desired to move the roller I39 out of the path of the cam I53 to facilitate movement of the table 4| to a loading position, a lever 3| I fixedly supported on the upper end of the stud I50 is moved downwardly until the pin 3% moves out of the slot 361. The lever 3H is then rocked clockwise (Fig. 4) to position the pin 336 in engagement with a notch 3I2 (Figs. 16 and 18) which serves to hold the roller I39 in its lowermost position. This downward positioning movement of the roller I39 into the position shown in Fig. 16 serves to move the valve stem 283 of the venting control valve 282 downwardly but does not move it sufliciently to allow passage of fluid from the venting pipe 28I into the exhaust pipe 281. In this position of the parts, the table 6| continues its movement toward the left until the cam 291 engages the follower 293 and moves the follower together with the plunger 293 downwardly to open the venting control valve 232. This movement serves in a manner above described to open the relief valve 213 so that the parts assume the position shown in Fig. 3 to allow substantially the full capacity of the pumps I93 and I54 to exhaust through the pipe 283 into the reservoir I32.

When it is desired to again start the reciprocatory movement of the work table 4|, the lever 3| I is shifted to release the roller I39 from its depressed position, that is, by swinging the pin 3% into alignment with the elongated slot 331. The main control lever 233 may then be moved in a counterclockwise direction into position 293a, which movement serves to trip the latch QSI to release the compression of the spring 230 which closes the venting control valve 282. The control lever 23311 is then moved in a clockwise direction into full line position. 233 (Fig. 4) to open the stop and start valve I95 to start the movement of the table 4 I.

Operation The operation of this machine will be readily apparent from the foregoing disclosure. Assuming a work piece 3I5 to have been mounted upon the table 4| for a grinding operation and the various parts including the table reversing A compression spring 3I3 is interposed bedogs I48 and I54 have been previously adjusted together with the loading dog I52, and the motor driven duplex fluid pumps including the large capacity pump I93 and the smaller capacity pump I04 together with the grinding wheel 55 have been set in motion by the electric control switches H6 and (ill, respectively (Fig. 1), the operation may be started by manipulation of the lever 3| and the control lever ans. The control lever 200, as above explained, is first moved into position 209a to trip the venting control valve 282, which serves to close the pressure relief valve 21f). The control lever 29%! may then be immediately shifted in a clockwise direction into the full line position (Fig. 4) to open the stop and start valve ISEI, which movement starts the reciprocatory movement of the table 4|.

After each reciprocation of the table 4|, as controlled by the table reversing valve 90, fluid from the small capacity pump IE4 is automatically diverted from the table reciprocation cylinders 8|] and BI to the indexing cylinder IZI and a measured quantity of fluid, as controlled by the metering valve I23, is allowed to exhaust from the exhaust end of the cylinder I2I to index the grinding wheel 55 transversely so as to present its operative face to a new portion of the work piece 3P5 on the next reciprocatory stroke. This operation is continued to effect the desired grinding operation while the grinding wheel 55 is indexed across the work piece 3|5 to the desired extent, after which it may be automatically reversed and indexed in the reverse direction on successive reciprocations of the table 4|. If it is desired to feed the grinding wheel 55 downwardly, this may be accomplished by rotation of the manually operable feed wheel 22I.

After a predetermined grinding operation has been completed, the roller I39 is depressed by movement of the lever 3 to move the roller I39 out of the path of the cam I53 on the reversing dog I54 to allow the table 4| to move toward the left into loading position so that the ground work piece 3I5 may be readily removed from the machine and replaced with a new piece to be ground. As the table 4| moves toward a loading position, the cam 291 engages the follower 298 to depress the plunger 293, which movement serves to depress the valve stem 283 to open the venting control valve 282, which movement serves to move the valve Z'II of the relief valve 210 upwardly away from the seat 2l2 (Fig. 3) which allows substantially the full capacity of the fluid pumps I83 and I to pass directly through the exhaust pipe 288 into the reservoir I62.

After the ground work piece 3|5 has been removed from the table 4| and a new work piece to be ground is mounted thereon, the grinding operation may be started again by first shifting the control lever 26!] to trip and close the venting control valve 282 in a manner previously described, after which the control lever 200a is shifted into the full line position 200 to position the stop and start valve I99, as illustrated in Fig. 4, which movement again starts the reciprocatory movement of the table 4|.

The reciprocatory movement of the table 4| may be stopped at any time during the operation of the machine by shifting the control lever 200 from the full line position into the broken line position 2e20, (Fig. 4) to close the stop and start valve I89. When the lever 200 is in the position 2000., the rock arm 2H is disengaged and, if de-' sired, the operator may push the hand traverse wheel I3 to shift the gear 6'3 into position 6311 into mesh with the rack bar 62 and thereafter to effect a manual traversing or adjusting movement of the work table 4| as desired.

If it is desired to adjust the position of the grinding wheel 55 vertically through a considerable distance, this may be accomplished by the fluid pressure operated lifting mechanism, controlled by the knob 2453. The control valve I28 may be actuated in either direction to start the fluid motor I29 to raise or lower the grinding wheel 55, as desired.

It'will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successively achieved. As many possible embodi" ments may be made of the above invention and as many changes might be made in the embodimentsabove 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 longitudinally reciprocable table, a fluid pressure piston and cylinder to reciprocate said table, a fluid pressure system including a motor driven fluid pump to supply fluid under pressure to said cylinder, a reversing valve to control the admission of fluid under pressure to opposite ends of said cylinder, a pair of pilot valves supported on opposite ends of said reversing valve, each of which is arranged to control the admission to and exhaust of fluid from an end chamber in opposite ends of said reversing valve, means including arod operatively connected to and arranged simultaneously to actuate said pilot valves, and a table actuated reversing lever operatively connected to actuate said rod to shift the pilot valve and thereby to shift the reversing valve so as to reverse the table movement.

2. In a grinding machine having a longitudinally reciprocable table, a fluid pressure piston and cylinder to reciprocate said table, a fluid pressure system therefor including a motor driven fluid pump to supply fluid under pressure to said cylinder, a reversing valve in said system, a table actuated pilot valve to control said reversing valve, a balanced type relief valve in said system normally to maintain a predetermined operating pressure in said system, and a table actuated venting valve to vent an open said relief valve automatically to reduce the pressure in said system substantially to zero when the table is stopped in an inoperative or loading position.

3. In a grinding machine having a longitudinally reciprocable table, a fluid pressure piston and cylinder to reciprocate said table, a fluid pressure system therefor including a motor driven fluid pump to supply fluid under pressure to said system, a reversing valve insaid system, a table actuated pilot valve to cor rol said reversing valve, a balanced type relief valve in said system normally to maintain a predetermined operating pressure in said system, a venting control valve operatively connected to said relief valve, and means including a table dog to actuate said venting control valve when the table moves to a loading position to vent and open said relief valve to thereby reduce the pressure in said system to zero.

4. In a grinding machine having a longitudinally reciprocable table, a fluid pressure piston and cylinder operatively connected to reciprocate said table, a fluid pressure system therefor including a motor driven fluid pump to supply fluid under pressure to said ccylinder, a reversing valve in said system, a table actuated pilot valve operatively connected to control the reversing valve, a manually operable stop and start valve in said system, a balanced type relief valve in said system normally to maintain a predetermined operating pressure in said system, a venting control valve operatively connected to vent and open said relief valve, a table dog having a cam operatively connected to actuate said reversing valve automatically to reverse the flow of fluid to said cylinder when the table reaches a loading position, and a cam on said dog to actuate said venting control valve to reduce the pressure in said system to zero to stop said table.

5. In a grinding machine having a longitudinally reciprocable table, a fluid pressure piston and cylinder to reciprocate said table, a fluid pressure system therefor including a motor driven fluid pump to supply fluid under pressure to said cylinder, a reversing valve in said system, a table actuated pilot valve to control said reversing valve, a manually operable start and stop valve in said system, a balanced type relief valve in said system normally to maintain a predetermined operating pressure in said system, a venting control valve operatively connected to vent and open said relief valve, a. table dog operatively connected to actuate said reversing valve automatically to reverse the flow of fluid to said cylinder when said table reaches a loading position, said table dog being arranged simultaneously to actuate said venting control valve to reduce the pressure in said system to zero to stop the movement of the table,

6. In a grinding machine having a longitudinally reciprocable table, a fluid pressure piston and cylinder t reciprocate said table, a fluid pressure system therefor including a motor driven fluid pump to supply fluid under pressure to said cylinder, a reversing valve in said system, a balanced type relief valve in said system normally to maintain a predetermined operating pressure in said system, and a table actuated venting valve to vent and open said relief valve automatically to reduce the pressure in said system to zero, means including a latch to hold said venting control valve in an open position, and a manually operable control lever to release said latch to start the movement of said table.

7. In a grinding machine as claimed in claim 6, the combination with the parts and features therein specified, of a latch to hold said venting control valve in an open position, a manually operable lever to actuate said table start and stop valve, and means actuated by movement of said lever to release said latch so as to close the venting control valve when the table movement is started.

8. In a grinding machine as claimed in claim 6, the combination with the parts and features therein specified, of a spring actuated latch automatically to latch and hold said venting .control valve when it is opened, a manually operable lever to actuate the table stop and start valve, and means actuated by movement of said lever to release said latch so as to close the venting control valve and thereby to close the relief valve before the table movement may be started.

HERBERT A. SILVEN,

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