US2360671A - Surface grinder - Google Patents

Description

Oct. 17, 1944- F. s. HAAS ET AL 2,360,671

SURFACE GRINDER Filed March 30, 1942 5 Sheets-Sheet 1 jifa 2 INVENTOR. few/Fwd Aha:

filamrflfnw ATTORNEY.

Oct. 17, 1944. s. HAAS AL 2,360,671

SURFACE GRINDER Filed March 30. 1942 5 Sheets-Sheet 2 IZ CZ 3 ZNVENTOR.

MWWAZUTORNEY.

Oct. 17, 1944. F. s. HAAS ET AL 2,360,571

SURFACE GRINDER F iled March 30, 1942 5 Sheets-Sheet 3 Oct. 17, 1 944. F, s s A v 2,360,671

SURFACE GRINDER Filed March 30. 1942 5 Sheets-Sheet 4 0d. 17, 1944. F s s AL 2,360,671

SURFACE GRINDER Filed March 30, 1942 5 Sheets-Sheet 5 ATTORNEY.

Patented Oct. 17, 1944 SURFACE GRINDER Frederick S. Haas, Cincinnati, Carl 0. Graves, Norwood, and Albert C. Janke, Cincinnati, Ohio, assignors to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application March 30, 1942, Serial No. 436,828

12 Claims.

This invention relates to grinding machines and more particularly to improvements in a surface grinding machine,

One of the objects of this invention is to provide an improved and efficient automatic surface grinding machine of the hydraulically actuated type.

Another object of this invention is to provide an improved hydraulic control circuit for controlling automatic operation of a surface grinding machine.

A further object of this invention is to provide an improved hydro-mechanical indexing mechanism for positively effecting the intermittent movements between the wheel and the work so that they will be uniform in extent.

Another object of this invention is to provide a surface grinding machine having an improved and simplified structural arrangement whereby the controls may be conveniently grouped for easy access from the operating station and which contains improved interlocking between the controls to prevent inadvertent manual operation of a control during power actuation of the part controlled thereby.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is a front elevation of a machine tool embodying the principles of this invention.

Figure 2 is an elevatio-nal view of the machine shown in Figure 1 as viewed from the left of that figure.

Figure 3 is a sectional view through the machine as viewed on the line 3-3 of Figure 1.

Figure 4 is a detail section on the line 44 of Figure 2.

Figure 5 is a detail section on the line 5-5 of Figure 1.

Figure 6 is an expanded view of the actuating and control mechanism for the saddle and the Wheelhead.

Figure '7 is a section on the line 1-7 of Figure 6.

Figure 8 is a section on the line 88 of Figure 2.

Figure 9 is a detail section on the line 9-9 of Figure 3.

Figure 10 is a detail section on the line Ill-J0 of Figure 9.

Figure 11 is a section on the line lI-l| of Figure 6.

Figure 12 is a diagrammatic view of the hydraulic control circuit.

In general, this invention deals with a surface grinding machine in which hydraulic means are employed for effecting relative reciprocation between the grinding wheel and the work support including trip operable means for automatically reversing the work support at the end of each stroke. In addition, improved hydro-mechanical means are employed for automatically effecting relative indexing between the work support and the grinding wheel at each reversal to effect a new grinding path whereby the grinding wheel may eventually traverse the entire surface of the work. After the surface has been ground means are provided for effecting automatic indexing between the grinding wheel and the work support in a direction normal to the direction of the first indexing to establish a new depth of out and for automatically reversing the direction of the first-named indexing movements whereby the grinding wheel will retraverse the entire surface of the work while grinding at the new depth.

Manual control means are provided for operating all of the slides and suitable selectors and interlocks provided to render these controls ineffective during power operation of any slide, thus improving the safety of operation of the machine.

More specifically, the machine comprises a bed or main support I0 upon the top of which is formed suitable guide ways H for supporting a saddle I2. As shown in Figure 3, the saddle is provided with guideways l3 and M for receiving a work supporting table 15 provided with complementary guide surfaces for engaging the surfaces l3 and M. A grinding wheel I6 is supported above the table on the end of a spindle H which is iournaled in bearings l8 and [9 formed in the vertically movable spindle carrier 20. As shown in Figure 6, the spindle carrier is guided for vertical movement on the dovetailed guides 2| and 22 formed on the rear of the bed 10. The spindle I1 is held against axial movement by means of a thrust bearing, indicated generally by the reference numeral 23 in Fi ure 3.

Referring to Figure 9, the thrust bearing includes a gimbal joint comprising an outer ring 24 supported on adjustable pivots 25 and 26 x I R, l I I threaded in the support 20, and an inner ring 21 supported on adjustable pivots 28 and 29 which are threaded in the outer ring 24 whereby the inner ring is supported for pivotal movement about an axis perpendicular to the pivotal axis of the outer ring. As shown in Figure 10 the inner ring 21 has an internal annular groove 30 for receiving an annular rib 3| formed integral with the spindle H. A hardened ring 32 is interposed between the rib 3| and one side of the groove 36 and a second ring 33 is interposed between the other side of the rib and the side of the groove formed by the threaded member 33 which carries springs 34 for taking up lost motion between the parts. The use of the gimbal joint simplifies alignment of the thrust bearing with the shaft after the latter is mounted in its bearings.

The spindle I! is driven by an electric motor 35 through a series of V-belts 36 which surround a pulley 3'! fastened to the end of the spindle l1, and a pulley 38 attached to the motor armature shaft 39. The motor is mounted on an angular bracket 46 which is vertically adjustable with respect to the support 28 for purposes of adjusting the tension in the belts 36.

A hydraulic control circuit is provided for the machine as shown in Figure 12 and a pump 4| which supplies fluid pressure to this circuit is also mounted on the bracket 40 as shown in Figure 3. It is provided with a drive pulley 42 which is connected by a series of V-belts 43 to a small pulley 44 formed integral with the pulley 38 whereby the motor 35 drives both the spindle 1 and the pump 4|. It will be noted that the spindle, pump and motor are all mounted on the vertically adjustable support 20, thereby eliminating the necessity of flexible drives in order to provide for relative adjustment between the tool spindle and the work support.

The spindle carrier 20 is adjusted on the guideways 2| and 22 of the machine frame In by a vertical screw 45 threaded through a nut 46 attached to the carrier 20. The screw is journaled and supported by anti-friction thrust bearings 41 in the support I and the lower end of the screw is journaled at 48 in the web 49 forming part of the base casting. Since the whole weight of the spindle carrier 20 is taken by the screw 45, the screw is always in tension and therefore the thrust bearings 41 are provided at the upper end of the screw to carry the weight of the spindle carrier, the bearing 49 at the bottom merely taking any lateral thrust on the screw.

Rotation of the screw is effected through a pair of spiral gears 50 and which are shown more clearly in Figure 6. The gear 50 is mounted on the taper 52 formed integral with the screw and i positively fastened thereto by a key 53, Figure 3.

The gear 5| is keyed at 54 to thetaper 55 formed on the end of a shaft 56. This shaft is journaled by anti-friction bearings 51 and58 in the base H) and beyond the bearing 58 there is attached a spur gear 59. This gear is connected through an idler gear 60 to a gear 6| pinned to a shaft 62. The shaft 62 has a wheel 63 fixed to the other end thereof whereby rotation of the hand wheel 63 will effect, through the intermediate gearing, rotation of the vertical screw 45. The shaft 62 also supports a. power operable gear 64 and when power operation is desired the gear 60 which is pinned to a shaft 65 is axially shifted out of mesh with the gear 6| and into mesh with the gear 64.

The cros slide of saddle 2 has 2. depending support 66 as shown in Figure 3 in which is mounted a nut 61 intermeshing with a cross screw 68. The cross screw has a plain journal 69 at one end and a thrust bearing 10 at the other end by which it is rotata'bly supported in the base Ill. The screw has an actuating gear keyed to the end thereof and this gear may be rotated selectively by either manual or power means. The manually operable means comprises a hand wheel 12, Figure 6, fixed to the end of a shaft 13, the shaft carrying a gear 14 which is operatively connected through intermediate idler gears and 16 to the gear Power operation is effected by a gear H which is connectible through intermediate reverse gearing to the gear I Power actuation of gear 15 and 64 is effected by separate hydraulic motors which are of the same'fconstruction and therefore explanation of one should suflice for both.

One such hydraulic motor means is shown more particularly in Figure 7 and comprises a pair of pistons '13 and 19 which are slidable in cylinders 88 and 8| formed in thecasti-ng 82 which is attached to the front of the machine. The pistons are rack pistons and interinesh with a common gear 83. As shown in Figure 6, the gear 83 has elongated hubs 84 and 85 and is supported for free rotation on the elongated hub 86 of the gear 17. The hub 85 of the gear 83 has an enlarged cup-shaped end 81 and the interior of this cup is provided with ratchet teeth 88 as shown in Figure 8. The elongated hub 86 of the gear if has a pawl carrier 89 fixed thereto by a key 3|] for supporting a ratchet pawl 9| which is urged into engagement with the ratchet teeth 88 by a spring 92.

It should be apparent now from Figure 8 that as the ratchet teeth 88 are moved in a counterclockwise direction that a ratcheting movement will be effected because the pawl 9| can be moved inward against the resistance of spring 92 by the teeth 88 so that no drive is effected. Upon rotation of the ratchet teeth in a clockwise direction the angular surface between the end of the pawl and the ratchet teeth is such that a driving action will be eifected. It should, therefore, be apparent that when fluid pressure is admitted to the upper end of cylinder and the lower end of cylinder 8| as shown in Figure '7 that the gear 83 will be rotated in a counterclockwise direction and a ratcheting action effected, while upon admission of pressure to the lower end of cylinder 80 and to the upper end of cylinder 8| 2, driving action will be effected. The ratchet, therefore, constitutes a, one-way clutch for driving the saddle.

Since these motors are provided chiefly for effecting indexing movements between the grinding wheel and the work, means are provided for varying the length of these movements because grinding wheels of various widths are used and the indexing movement of the saddle should be approximately equal to the width of the wheel. In the case of the vertical adjustment, variation is necessary to control the depth of cut. This mechanism is based on the proposition that the actuating pistons always hit the end of their cylinders on the power or actuating stroke but are limited on their return or ratcheting stroke. This mechanism comprises a sleeve 93 which is supported for free rotation on the hub between a shoulder 96 formed integral with the hub and a cap plate 9'! threaded on the end of the elongated hub 86 of the gear 11. A cupped graduated plate 99 is secured to the end of the sleeve 93 as by screws Hill. The sleeve 93 has a set of gear teeth IIlI, Figure 8, formed on the periphery thereof which intermesh with a worm I02 integral with a cross shaft I03 having an operating knob I04.

As shown in Figure 11, the sleeve 93 carries an axially extending lug I05 which projects into an arcuate slot I06 formed on the periphery of the hub 85 of the gear 83. The pistons I8 and I9 are shown in their maximum return position in Figure 7 which means that the shoulder III! on the part 85 has engaged the limiting stop lug I05.

It should now be obvious that the operating knob I04 may be manually rotated in a direction to effect clockwise adjustment of the stop I65 such as the dotted line position indicated by the numeral I08 and thereby restrict counterclockwise rotation of the part 85. This will correspondingly shorten the length of the ensuing power stroke.

Since the plate 99 is attached to and moves with the worm gear IIlI it carries graduations I09 to indicate the length of the indexing movement.

It should now be obvious that the saddle may be manually adjusted through rotation of the hand wheel I2, or it may be power indexed variable amounts by the hydraulic motor means. When power indexing is desired the gear I5 is disengaged from the gears I4 and I6, and a gear III), which is formed integral with the gear 15, is shifted into engagement with the gear 11. This serves to disconnect the hand wheel I2 from the power means and prevents rotation thereby during power indexing.

The gears I5 and H6 are secured to a shaft III, which is provided with an operating knob II2 located in the front of the machine. The shaft is provided with grooves I I3 and H4 which are engageable by a spring pressed detent 5 for holding the shaft in either one of its two positions. Means are also provided for simultaneously connecting the hydraulic motor in operative relation to the control circuit when the gears are shifted to a power operable position and this is accomplished by utilizing a portion of the shaft I II as a valve plunger, which portion is indicated by the reference numeral H6. The valve plunger is provided with two grooves I I I and H8 and when the plunger is in the position shown in Figure 6 the four ports II9. I2" I2I and I22 shown in Figure 12 are all interconnected by the groove H8. thereby short circuiting the two control lines I23 and I24, as well as the two motor lines I25 and I26.

The line I25, as shown in Figure 12, is connected to the upper end of cylinder 80 and the lower end of cylinder 8| whereby the admission of flu d pressure to channel I25 will cause one direction of rotation of the gear 83. Line I26 is connected to the upper end of cylinder BI and the lower end of cylinder 80 whereby the admission of fluid pressure to this channel will cause an opposite direction of rotation of the gear 83. When the valve is shifted to the posit on shown in Figure 12 the annular groove H8 interconnects ports I2I and I22 to establish communication between lines I24 and I26 and the second roove II I interconnects ports I28 and H9 whereby channel I25 is connected to channel I29. It will thus be seen that selector means are provided for choosing between manual operation and power indexing of the saddle and that when power indexing is selected that the hand wheel is disconnected from the power mechanism so as to prevent power operation thereof.

When the gear III] is shifted into mesh with gear 11, the drive from the power gear 11 to the screw 63 is through gear H0 and idler gears I36 and I3I. The gear I3I is formed integral with gear I6 which is in constant mesh with the gear II. The gear pair I6, I3I is pinned to a shaft I32, the ends of which form pistons which are slidable in cylinders I33 and I34. The admission of fluid pressure to cylinder I33 shifts the gears to reverse the driving connection between the gear TI and the cross feed screw 68. This is accomplished by moving the gear I3I out of mesh with the gear I30 and moving the gear I6 into mesh with the gear I5 in its new position whereby the drive now is from the gear I! through gears IIlI, I5 and I6 to the gear I I.

Referring to Figure 12, the cylinders I33 and and I34 are connected by channels I35 and I36 to ports I31 and I38 of a saddle reversing control valve I39 whereby the position of this valve determines the position of the reversing gears. The manner of operation of this valve will be explained in connection with the explanation of the hydraulic circuit.

The indexing of the vertical feed mechanism is effected by hydraulic means of the same construction as for the saddle and, as shown in Figure 12, comprises a pair of cylinders I46 and MI in which slide a pair of rack pistons I42 and I43 respectively. These rack pistons mesh wit an intermediate gear I44 which is fixed to a sleeve I45 to which is attached the previously mentioned power gear 64. The operation of this motor and the interconnection of the gear 64 with the pinion 59, is effected by shaft 65 which carries the gear 66. In other words, when this shaft is axially moved by its operating knob I46 as shown in Figure 6, the gear 66 is moved out of mesh with the gear 6! and into mesh with the gear 64. it being remembered that it is al ways in constant mesh with the gear 59. The shaft 65 has a pair of V-shaped grooves I41 and I48 which are alternately engaged by the spring pressed detent I 46 for holding the shaft in either one of its two positions.

The shaft 65, as shown in Figure 12, is provided with annular grooves I 56 and I 5I which in the position shown interconnects ports I52 and Hill with the motor ports I54 and I55 respectively. The port I54 is connected by channel means I56 to the upper end of cylinder I46 and the lower end of cylinder MI, While the port I55 is connected. by channel means l5? to the upper end of cylinder I4I and the lower end of cylinder I40.

When the valve is shifted to the manual control position. which corresponds to thegear 66 being in mesh with the gear 64. as shown in Figure 6, the ports I52 and I53 are interconnected and the ports I54 and I55 are closed.

The mechanism for regulating the amount of indexing of the vertical feed is the same as that described for the saddle, the operating knob for adjusting the indexing mechanism being indicated by the reference numeral I58 in Figure 1. A graduated dial I59. as shown in Figure 6, is also provided for indicating the amount of the indexing movement.

In surface grinding operations it may be necessary to remove several layers of material from the work in order to grind it to a desired size, and it may be desirable to know the complete amount of stock removed in such cases.

For this purpose an additional dial I69 is provided which is so mounted that it can be set at will to zero at any time. To this end an auxiliary shaft I6I is operatively connected to the end of the drive shaft 56 and extended through the front of the machine for receiving a cup-shaped dial I69. The dial is frictionally connected to the shaft by a disk spring I62 which is interposed between the dial and a nut I63 threaded on the shaft. By tightening the nut, the dial is forced into frictional engagement with the face of an annular rib I64 formed integral with the shaft. When the proper friction is developed a cotter pin I65 is passed through the nut and shaft to hold the nut against relative movement with respect to the shaft. A covering button I66 is snapped into the dial to protect the parts.

The table I is reciprocated by a hydraulic motor comprising a piston I61 and a cylinder I68, the piston being connected to both ends of the table by a piston rod I69 which extends through both ends of the cylinder. The fluid pressure for driving the table is derived from the pump 4| which has an intake I1I through which fluid is withdrawn from a reservoir I12 and a delivery channel I13 which is provided with the necessary relief valve I14. The flow of fluid from the pump to the table cylinder is controlled by a reversing valve I15, a stop-deceleration valve I16, a. table controlled pilot valve I11, and a rate valve I19. The pilot valve I11 controls the positioning of the plunger I8I' of stop valve I16 and has a plunger I99 which is manually controlled by the stop lever I8! which is mounted on the front of the saddle as shown in Figure 1.

To this end the pilot valve has a pressure port I82, a pair of return ports I83 and I84, and a second pair of ports I85 and I86 which are connected by channels I81 and I88 to opposite ends respectively of the stop-deceleration valve I16. The plunger I89 is shown in a running position whereby the pressure port I82 is connected to the port I86 to shift the plunger I8I' of valve I16 to its left hand position. In this position a channel I89 which receives the return flow from the table cylinder regardless of its direction of movement is connected to a channel I99 by means of the cannelure I9! formed in the plunger I8I'. The channel I99 leads to port I92 of the rate valve which also has an exhaust port I93. The plunger I94 of the rate valve has a variable resistance spool I95 which may be axially adjusted to vary the flow through the port I92 and thereby change the rate of table movement.

The adjustment is effected by a shaft I96, which as shown in Figure 5, is rotatably supported by the saddle I2, and provided on one end with an eccentric pin I96 and on the other end with an operating knob I 96. The pin fits in a vertical slot 196a formed in a block I961) attached to the end of the plunger I94. Rotation of the knob will thus variably throttle the exhaust flow from the table motor to change its rate.

The reversing valve I15 has a pressure port I91 which is directly connected to the output of the pump 4|, and this port is alternatively connected to the motor ports I98 and I99 by the shiftable plunger 299 which has annular grooves 29I and 292, the groove 29! connecting port I98 to a return line 293 and a groove 292 connecting the pressure port I 91 to port I99. The ports I98 and I99 are connected by channels 294 and 295 to opposite ends of the cylinder I68. Thus, with the reversing valve in the position shown the piston I61 will move to the left and the exhaust fluid will pass through channel 293 to port 294' of the table controlled pilot Valve I11. The table controlled valve has a plunger 296 which is operatively connected to a trip lever 291 which is mounted on the front of the saddle as shown in Figure 1. This trip lever has two wings 298 and 299 which are adapted to be operated by trip dogs 2 I9 and 2I I, the trip dogs rotating the lever until the plunger. 296 is moved slightly beyond a middle position-at which time a spool 2 I2, which is larger in diameter than the rest of the plunger, passes a presure port 2I3 whereupon fluid pressure will enter either chamber 2 I4 or 2 I5 to complete the shifting of the plunger. The valve is thus self-actuated after it passes a mid-position.

When the table reversing valve plunger 299 is shifted to its right hand position the annular groove 29I connects the pressure port I91 to port I98 and the annular groove 292 connects port I99 to port 216 whereby the return flow from the right hand end of cylinder I68 will be directed through channel 2I1 to port 2I8 of the table controlled valve I11. Itwill now be apparent that the exhaust fluid from one end of' the table cylinder is delivered to port 294 and the exhaust fluid from the other end of the table cylinder is delivered to port 2I8 of valve I11.

The plunger 296 serve to alternately connect these ports to the channel I89 previously described, whereby the rate control valve may function to throttle the exhaust flow from table cylinder regardless of its direction of movement. In addition, the valve I11 acts a a deceleration valve to slow down the table, before it reverses. This i accomplished by providing two tapered spools 2I9 and 229 so that when the plunger 296 is moving toward the right the tapered spool 2| 9 acts to restrict the flow through port 294 before cutting it off and the tapered spool 229 acts to restrict the flow through port 2I8 when the plunger 296 is moving toward the left. regardless of the direction of table movement, the exhaust flow from either end of the table cylinder i restricted sufiiciently to slow down the table before the reversing movement takes effect. Surface grinding operations are accomplished by effecting relative reciprocation between the grinding wheel and work and effecting intermittent movements or lateral indexing between strokes and since the reversing and indexing can occur simultaneously reversing mechanism is coupled with the saddle indexing mechanism in such a manner that upon trip operation of the table control valve I11 the table is automatically stopped, the indexing movement performed and the table restarted again in the new direction. The valve I11 does not directly cause shifting of the table reverse valve but controls the shifting of a pilot valve indicated generally by the reference numeral 22I which, in turn, causes shifting of a reverse valve 222 which causes operation of the saddle indexing motor previously described, the pistons 18 and 19 executing a power stroke. Upon completion of this power stroke fluid pressure is directed by the pilot valve 22I to effect simultaneous shifting of the table reverse valve plunger 299 and the cross feed reverse valve 222 whereby the table starts on its return movement, and the indexing pistons 18 and 19 execute their return ratcheting movement.

Thus,

This is accomplished in the following manner: the table valve I11 is provided with a pair of ports 223 and 224 which are alternately connected to the pressure port 2I3 by the plunger 206 and these ports are connected by channels 225 and 226 to ports 221 and 228 located in opposite ends of the pilot valve 22I whereby the plunger 229 will be alternately positioned in opposite ends of the valve, dependent upon the direction of movement of the table.

The line 225 also has a connection to port 229' and the line 226 has a connection to port 230, these two ports being located in the cross feed reverse valve 222. This valve has two ports 23I and 232 which are connected to the common supply line I24 for the cross feed indexing motor. With the parts stabilized in the position shown in Figure 12 it should now be apparent that if the plunger 206 is shifted to the right and pressure connected to channel 225 that the pilot valve plunger 229 will be shifted to the right which will produce no immediate effect but the fluid pressure will also flow through ports 229 and 23I of valve 222 to the line I24 and thereby to the lower end of cylinder 80 and the upper end of cylinder BI whereby the pistons 18 and 19 will move on a power stroke to eifect indexing of the saddle.

When the piston 18 has completed its movement it will connect port 233 located in the lower end of cylinder 80 to port 234 whereby the actuating fluid may now continue through line 235 and check valve 236 to port 231 of the pilot valve 22I. Since the pilot valve plunger 229 has just been shifted to the right the port 231 will now be connected by the annular groove 238 to port 239. The fluid pressure can thus continue through port 231, groove 238 and port 239 to channel 240 which has one branch 24I leading to port 242 located in the left end of the cross feed reverse valve 222, thereby shifting its plunger 243 to the right to effect a reversing or ratcheting movement of the pistons 18 and 19. Fluid pressure will also flow from channel 240 through the other branch 244 to port 245 of the table reversing valve, shifting the plunger 200 to the right, thereby starting the table in its new direction of movement.

The shifting of the cross feed reverse valve 243 to the right resulted in the connection of port 229' with port 246 by the groove 241 and thereby connected the fluid pressure coming from valve I11 to line I29 to effect the ratcheting movement. At the same time, port 232 is connected to port 230 and thereby to line 226 which at this time is connected to exhaust by valve I11. This leaves the parts in such position that upon the next shifting of the plunger 206 into the position in which it is now shown in Figure 12 that the fluid pressure admitted to line 226 and thereby to port 230 may pass through port 232 to effect the next indexing movement of the cross slide.

It should now be apparent that trip operation of the pilot Valve 206 by the table causes first a throttling of the return flow from the table motor, thereby slowing down the table and then after the valve passes its midposition it directs fluid to cause operation of the index motor and a shifting of the pilot valve plunger 229 to the right as viewed in Figure 12, whereby after the completion of actuation of the hydraulic index motor, the operating pressure therefrom will be directed to effect a shifting of the table reverse valve plunger 200 to the right and a shifting of the reverse valve plunger 243 to the right, resulting in a reversal in the direction of table movement and a reverse or ratcheting movement of the ratcheting motor. Thus, the valve plungers 200, 229 and 243 remain in a right hand position during movement of the table piston I61 to the right.

Upon the next trip operation of the pilot valve plunger 206 the table will be decelerated by the plunger 206, throttling the return flow from the motor through port 2I8 and then after the plunger passes its midposition pressure fluid will be directed to channels 226 and I24 to cause operation of the indexing motor and to port 228 to effect shifting of the plunger 229 into a position such that when the indexing motor has completed its movement fluid pressure will be directed from port 231 to port 248 and channel 249. This channel has one branch leading to port 250 of the cross feed reverse valve, thereby shifting the plunger 243 to the left, and a second branch leading to port 25I of the table reverse valve, thereby shifting the plunger 200 thereof to the left. The shifting of plunger 200 immediately causes reversal in the direction of operation of the table and the shifting of plunger 243 reverse the direction of operation of the index motor.

These operations alternately repeat until the grinding wheel has completely traversed the surface of the work. If it is desired that a second layer of material be removed from the work, the vertical indexing mechanism is'adjusted in accordance with the thickness of material to be removed and the trip dogs 252 and 253 shown in Figure 2 are adjusted in accordance with the width of the work to operate a trip lever 254 mounted on the side of the bed as shown in Figure 4. This lever is fixed to a shaft 255 which carries a crank 256 that is operatively connected to the valve plunger 251 of a pilot valve 258 shown in Figure 12. This valve has a pressure port 259 which is supplied directly by the pump M, a pair of exhaust ports 260 and 26I, and a second pair of ports 262 and 263 which are connected by channels 264 and 265 respectively to opposite ends of the reversing valve I39.

The pilot valve serves to control reversible operation of the plunger 261 of valve I39. This valve has two ports I31 and I38 as previously explained which are alternately connectible with a pressure port 268 to cause shifting of the gear I3I and shifting of a plunger 269 of a secondary pilot valve 210. Since the reverse valve I39 has a constant pressure port 268, the shifting of plunger 261 to the right as viewed in Figure 12 in response to trip actuation of the pilot valve 251 connects this port to port I31, which results in the shifting of gear I3I and valve plunger 269. At the same time the fluid pressure flows through a branch connection of channel I35, interconnected ports 21I and 212 of an index reverse valve 213, and channel 214 to port I52 of the manually controlled valve 65. When power indexing of the vertical feed is desired, the valve 65 is pulled outwards by the knob I46, thus placing the valve in the position shown in Figure 12 and shifting the gear 60 into mesh with the gear 64 shown in Figure 6. The ports I52 and I53 are now connected to the ports I54 and I55 respectively and since the port I52 is under pressure, the indexing pistons I42 and I43 will advance to index the vertical slide. The ratchet connection between gear I45 and gear 64 is in efiect a one-way clutch which is operative only in the direction to move the grinding wheel being connected to port 284 whereby the fluid will flow through channel 285 and interconnected ports I53 and I55 of the manual control valve 65 to return the indexing pistons.

Attention is invited to the fact that the plunger 283 in shifting to the right uncovers port 286 which is branch connected to line I whereby the pressure in this line will enter the left end of the valve 213, and hold the plunger 283 in its new position.

Attention is also invited to the sequential action which takes place after the last stroke of the grinding wheel over the work in a given plane. It should be evident that the trip operation of the pilot valv 251 by either the dog 252 or the dog 253, which dogs are carried by the saddle, is the result of movement of the saddle by the saddle indexing motor.

Therefore, the sequence is as follows: one of the table dogs 2 I0 or 2 causes trip operation of the pilot valve plunger 206 which, in turn, causes indexing of the saddle, and the indexing of the saddle causes trip operation of the pilot valve 251 which, in turn, causes operation of the vertical indexing motor and shifting of the reverse gear I3I of the saddle drive train whereby a relative lateral indexing and vertical indexing are effected sequentially between the grinding wheel and the work. The shifting of the reverse gear conditions the drive train to the saddle so that the next indexing movement of the saddle will be in the opposite direction.

If still another layer of material is to be removed from the work the other trip dog, such as 253, will be set to shift the trip plunger 251 after the grinding wheel has covered the work and fluid will be directed through channel 265 to effect shifting of plunger 261 to the left, resulting in the admission of fluid pressure to channel 214 to cause a cycle of operation of the indexing motor and simultaneously a shifting of the saddle reverse gear I3I.

The operation of the machine may be stopped at any time by throwing the stop lever I8I which moves the valve I80 to the right, interconnecting the pressure port I82 to port I85. This results in the movement of plunger I8I to the right. This movement is slow at first in order to effect a throttling action at port 281 by tapered spool 288 upon the return flow from the table motor and thus a smooth deceleration of the table to stop. The throttling action is obtained by T- drilling the end of the plunger I8I' so that th fluid in the end of the valve is forced through the drilling 289 into an annular groove 290. The spool 29I is made slightly smaller in diameter than the rest of the plunger to form a restriction to flow from the groove 290 to the port 292. By the time that the tapered spool has closed the port 281, the spool 29I has passed the port 292 sufficiently to permit the rest of the plunger movement to be at a fast rate.

The table I 5 is manually traversed by a handwheel 293 attached to the end of a shaft 294 which as shown in Figure 12 carries a splined gear 295 adapted to mesh with a "rack bar 296 attached to th underside of the table as shown in Figure 3. Means are provided under the control of the stop valve I16 to effect automatic disengagement of the gear 295 from the rack 296 during power operation of the table. In other words, when the plunger I8I' is in the position shown, a pressure port 291 is connected to port 298 and thereby through line 299 to port 300 in the housing for shaft 294. This port is connected by interdrilling 30I in the shaft 294 to space 302, thereby holding the gear 295 out of mesh with the rack 296 againstthe compression of a spring 303.

When the plunger I8I' is shifted to the right the port 298 is connected to an exhaust port 304 which permits the spring 303 to function and engage the gear 295 with the rack andthus it is ready for manual operation. At the same time, the plunger interconnects ports 305; and 306 to which branches of lines 204 and 205 are connected, thus forming a by-pass from one end of the table cylinder to the other, so that the fluid in the table cylinder will not interfere with manual operation.

Referring to Figures 2 and 4, attention is invited to the means provided for manually operating the saddle trip mechanism. As shown in Figure 2, a pull rod 301 is slidably mounted in the housing 308 and is provided on one end with an operating knob 309 and near the other end with a notch 3I0 in which fits the end of a crank 3 attached to the end of shaft 255. Thus the pilot valve plunger 251 may be manually or power operated.

There has thus been provided an improved surface grinding machine which is simple and compact in construction and which has complete automatic control.

What is claimed is:

1. In a surface grinding machine, the combination with a bed, a saddle reciprocably mounted on the bed, a table reciprocably mounted on the saddle, and a grinding wheel support, of a fluid operable motor for reciprocating the table, a fluid operable motor for indexing the saddle, a reversing valve for the table motor, a source of pressure connected thereto, a pilot valve trip controlled by the table for connecting said source of pressure to effect operation of the index motor, and means responsive to operation of the index motor in completing movement of the saddle to connect the motor operating pressure for shifting said reverse valve.

2. In a surface grinding machine having a grinding Wheel and a work supporting table, the combination with a saddle for supportin the table for intermittent movement laterall of the grinding wheel, of means for reciprocating the table and effecting intermittent movements of the saddle after each table stroke including separate fluid operable means for effecting the respective movements, a reversing valve for each of said fluid operable means, a source of pressure connected to the table reversing valve, a pilot valve trip controlled by the table for connecting said source of pressure to the fluid operable means for the saddle through its reversing valve, and means responsive to operation of the last-named fluid operable means for connecting its operating pressure for shifting both of said reverse valves.

3. In a surface grinding machine having a grinding wheel, a fluid reciprocable table and a fluid indexible saddle supporting the table, the

combination of control means therefore including a reversing valve for the table, a pilot valve trip controlled by the table, a, source of pressure directly connected to both of said valves, means connecting the pilot valve to the fluid indexing means whereby shifting of the pilot valve will effect operation of said means, and means for subsequently connecting the operating pressure for said fluid indexing means to effect shifting of the reversing valve whereby reversal of the table Will occur after the indexing movement has been completed.

4. In a surface grinding machine having a grinding wheel and a work supporting table, the combination of means for effecting indexing movements between the wheel and the table in a direction laterally of the wheel including fluid operable piston means having a power stroke in one direction and an idle return stroke, a trip controlled valve operable by the table and having a source of pressure connected thereto, means connecting said valve to said piston means whereby trip operation of said valve will effect a power stroke of said piston means, a reversing valve interposed between said trip-controlled valve and the piston means, and means controlled by said piston means in completing the power stroke to effect shifting of said reversing valve whereby the piston means will return automatically to a starting position.

5. In a surface grinding machine having a grinding wheel and a reciprocating work support, the combination of means for effecting intermittent relative movements between the grinding wheel and the work support including a pair of rack pistons, a pinion interposed between said pistons, motion transmitting connections from said pinion to effect said intermittent movements, a pair of channels supplying said pistons, a source of pressure, a reversing valve for alternately connecting said source of pressure to said channels, and means connectible by the pistons in completing their power stroke to effect firing of said reversing valve.

6. In a surface grinding machine having a grinding wheel and a work supporting table, the combination with a saddle for supporting the table for intermittent movements relative to the wheel, of means for effecting said intermittent movements including a piston and cylinder, motion transmitting means connecting the piston to the saddle including a ratchet connection whereby advance of the piston will effect said movement and the return stroke of the piston will be an idle movement, control means including a table operated pilot valve and a reversing valve serially connected to said piston, a reversing valve for the table, a source of pressure connected to said t'able reversing valve and said pilot valve, an auxiliary valve for controlling hydraulic shifting of said reversing valves, means connecting said pilot valve for shifting said auxiliary valve, a supply channel extending from said cylinder to the auxiliary valve, said channel being opened by the piston upon completion of its movement in one direction to connect the piston operating pressure to said auxiliary valve and thereby effect shifting of said reversing valves.

'7. In a surface grinding machine having a grinding wheel and a work supporting table, the combination of transmission means for reciprocating the table and effecting relative indexing between the table and the wheel comprising a fluid motor for the table having a pair of ports, a pump, a fluid shiftable valve for reversely conreturn lines, a valve shiftable by the table for alternately blocking said return lines to stop the table, means connecting said lines to a rate valve for controlling the rate of table movement, a fluid operable piston, motion transmitting connections from said piston including a one-way clutch for indexing the table, means to vary the stroke of the piston and thereby the length of the indexing,

. a fluid shiftable reversing valve for said piston,

necting said ports to the pump and to individual a pilot valve shiftable by the table concurrently with the first-named shiftable valve for transposing pressure and return connections of said reversing valve to cause an indexing stroke of the piston, and an auxiliary pilot valve for connecting a port uncovered by the piston to effect shifting of both reverse valves and thereby start the table after it has been indexed and to effect return movement of the piston.

8. In a surface grinding machine having a grinding wheel and a reciprocating table, the combination of means for indexing said table after each stroke thereof including a fluid operable piston, a shiftable reversing valve, a pilot valve shiftable by the table for transposing pressure and exhaust connections to the reversing valve to actuate said piston in one direction and valve means opened by the piston to effect shifting of the reversing valve and thereby return movement of the piston whereby an indexing cycle will be effected for each shift of the pilot valve.

9. In a surface grinding machine having a grinding Wheel and a work supporting table, the combination of means for effecting relative movement between the table and the grinding wheel in two directions including a fluid operable motor for effecting a reciprocating movement in one direction, a second fluid operable motor for efiecting an intermittent unidirectional movement in a second direction, individual reversing valves for the respective motors, a source of pressure connected to one of said valves, a pilot valve trip controlled by the table for transposing the pressure and exhaust connections to the other reversing valve to effect operation of the second-named motor, means connectible by the second motor upon completion of its movement in one direction to connect its operating pressure for shifting both of said reverse valves, the shifting of one of said reverse valves automatically disconnecting the shifting pressure, and means subsequently connectible by the same reversing valve for connecting the source of pressure to hold said valves in their shifted position.

10. In a surface grinding machine having a grinding wheel and a work supporting table, the combination of means for effecting intermittent movement between the grinding wheel and the table including a fluid operable motor, a reversing valve, a pair of channels extending from the reversing valve to the motor, a source of pressure continuously connected to the reversing valve, an auxiliary pilot valve operatively connected to control the shifting of the'reversing' valve, a supply line from the motor to the auxiliary valve, means operable by the motor for momentarily connecting said supply line to the motor operating pressure to automatically effect its own reversal, and manually operable means for interconnecting said motor lines and said supply line to prevent operation of the motor upon shifting of the pilot valve.

11. In a surface grinding machine having a bed, a wheel head slide mounted on the bed for vertical movement, av reciprocating table, a saddle for supporting the table on the bed for intermittent movement transversely of the grinding wheel, fluid operable means for reciprocating the table, means for imparting intermittent movement to the saddle at each reversal of the table including a fluid operable piston, a relatively rotatable screw and nut, one of which is connected to the saddle, motion transmitting gearing connecting the piston for effecting said relative rotation, means controlled by the table for efiecting actuation of said piston, a second relatively rotatable screw and nut for imparting movement to the wheel head, a fluid operable piston and interconnected gearing for effecting relative rotation between the last-named screw and nut, a reversing gear in said motion transmitting gear, and means controlled by the saddle for causing actuation of the last-named piston and shifting of said reversing gear.

12. In a surface grinding machine having a bed, a grinding Wheel rotatably supported thereon, a work table, a saddle for supporting the work table on the bed for movement transversely of the grinding Wheel, means to efiect said movement including a pair of co-axial gears, manually operable means for rotating one of said gears, fluid operable means for rotating the other of said gears, a screw journaled in the bed and having an interengaged nut connected to the saddle, intermediate gearing operatively connected to the screw and including a shiftable gear couple for alternately engaging said co-axial gears for selective manual or power actuation of said screw, means simultaneously operable with the shifting of said gear couple to connect or disconnect fluid pressure to said fluid operable means, and additional shiftable gearing in said intermediate gearing for changing the direction of rotation of said screw for unidirectional rotation of said coaxial gears.

FREDERICK S. HAAS.

CARL O. GRAVES.

ALBERT C. JANKE.

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