US2376237A

US2376237A - Grinding machine

Info

Publication number: US2376237A
Application number: US470290A
Authority: US
Inventors: Decker Jacob; Albert D C Stuckey
Original assignee: Cincinnati Milling Machine Co
Current assignee: Milacron Inc
Priority date: 1942-12-26
Filing date: 1942-12-26
Publication date: 1945-05-15
Anticipated expiration: 1962-05-15

Description

6 Sheets-Sheet l May 15, 194 J. DECKER ETAL GRINDING MACHINE F1151 Dec. 26, 1942 i S p H W. F H D D N H H I W H MW H J NU MR DH m .QN N mfl Hv Q 1. ut E55: E55 2 I: M Y B AN v v E O OH H H U Q Q N NHN May15, 1945- J. DECKER -ET AL GRINDING MACHINE e Sheets-Sheet 2 Filed Dec. 26, 1942 5 4 a o a a W w a 5 V v T JW l 7 5 6 v m m m 4 9 6 6 k w 7 7 o L f U M. v v 7 urn/WE r 7. j [7 2E o mm M 5 im i 2 w 4a. m H m w 9. a B 4/ 5 l 2 a. 5 6 W ./7 l 3 v F May 15, 1945.

J. DECKER ET AL GRIND'ING MACHINE Filed Dec. 26, 1942 6 Sheets-Sheet 5 A77 p/YEY y 15, J. DECKER ET AL I GRINDING MACHINE 6 Sheets-Sheet 4 Filed Dec. 26, 1942 8 f a 3 a s 34 2. mm a n il 1 11 1 \KMM M \\\kmm y 1945- J. DECKER ET AL GRINDING MACHINE 6 Sh ee'tS-She'et- 5 Filed Dec. 26, 1942 N NHN Arr mm y 1945. Y J. DECKERETAL 2,376,237

GRINDING MACHINE Filed Dec. 26, 1942 6 Sheets-Sheet 6 via 25 A T O/P/YEX Patented May 15,1945

GRINDING MACHINE Jacob Decker, Cincinnati, and Albert D. C.

Stuckey, Hamilton, -hlo, assignora to The Cincinnati Milling Machine 00., Cincinnati, Ohio, a corporation of Ohio Application December 26, 1942, Serial No. 410,290

16 Claims.

This invention relates to machine tools and more particularly to improvements in grinding machines.

One of the objects of this invention is to provide improved means in a grinding machine for controlling relative movement between the grinding wheel support and the work support, and more particularly the movements of the grinding wheel support toward and from the work support.

Another object of this invention is to provide an improved automatic infeeding mechanism for a grinding machine.

Another object of this invention is to provide in conjunction with an automatic infeed mechanism means whereby a rapid traverse movement may be superimposed at will upon the infeeding movement to change the zone of the movement without interfering with the infeeding mechanism, or may be utilized alone to quickly change the position of the wheel.

A further object of this invention is to provide a grinding machine having an improved mechv anism for infeeding the grinding wheel, interlock means to prevent traversing of the table during the infeeding, and means for releasing said interlocking means after the infeeding operation is completed whereby the work support may be reciprocated by hand before return of the grinding wheel.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction withthe 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:

Figure 1 is an elevational view of a grinding machine embodying the principles of this invention.

Figure 2 is a vertical section through the hand wheel for traversing the grinding wheel support.

Figure 3 is a plan view of the graduations associated with the hand wheel.

Figure 4 is a detail section on the line 4-4 of Figure 3. 7

Figure 5 is a section on the line 5-5 of Figure 2.

Figure 6 is a view of'the handwheel stop meclsianism as viewed on the line 5-6 of Fi ure Figure 7 is a detail section on the line |--I of Figure 6.

Figure 8 is.an enlarged detail section on the line 8'! of Figure 7.

5 Figure 9 is an enlarged detail view of the rapid traverse control lever.

Figure 10 is an enlarged detail view of the disconnect clutch in the infeed train.

Figure 11 is a detail section on the line |I--ll of Figure 10.

Figure 12 is an enlarged detail view of the rapid traverse control valve.

Figure 13 is an enlarged detail view of the throttle valving in the infeed cylinder.

Figure 14 is a diagram of the hydraulic control circuit. 1

Figure 15 is a continuation of the diagram shown in Figure 14.

Referring to Figure 1, the reference numeral l0 indicates in general the bed of a cylindrical grinding machine upon the top of which a work supporting table ii is suitably guided for reciprocating movement, and a grinding wheel support, indicated generally by the reference numeral i2, is reciprocably mounted for movement at right angles to the direction of movement of the work support. A grinding wheel I! is rotatably mounted on the support 12 and suitable power operable means not shown are mounted on 0 the support for rotating the grinding wheel.

In addition to manual control, an automatic 1 infeed cycle control mechanism is provided for moving the grinding wheel support at a rapid traverse rate to position the wheel adjacent the work; at a feeding rate to grind the work; and then for effecting a rapid return movement. During such an operation means are provided for locking the table against reciprocatory movement until the grinding wheel has finished 40 grinding, and means for automatically releasing the table for reciprocation while the work is being cleaned up, along with means for superimposing a fast movement without disturbing the setting or operation of the infeeding mech- 5 anism.

All movements are imparted to the-grinding wheel support through either one of two connections, one of which comprises a nut I4 which is supported from the underside of the wheel support as shown in Figure 1, and which inter-' meshes with a feed screw l5 which is rotatably journaled at opposite ends in the bed. The screw is capable of rotational as well as limited axial movement, the axial movement being uti- 66 lized when fast cyclic movements are desired,

while the rotary movement is utilized when. slow or feeding movements are desired.

The mechanism for imparting fast movements to the grinding wheel support during an automatic infeed cycle, for instance, comprises a piston l6 which is formed integral with the end of the screw IS, a cylinder l1 in which the piston I6 is reciprocably mounted and an adjustable cylinder head 18 mounted in the end of the cylinder and operatively connected by a screw [8 to a rotatable head 20 having an operating handle 2|. By rotating the handle.2l the cylinder head is adjusted to determine the limit of the return movement of the wheelhead. Rapid return movement of the grinding wheelhead is effected by a separate piston 22 and cylinder 23, Figure 14, the cylinder being formed integral with the wheelhead l2 and the piston being connected by a piston rod 24 to the bed I0.

Manual adjustment of the wheelhead is effected by manually rotating a pinion 25 which is supported on a shaft 26 that is journaled in the bed parallel to the axis of the lead screw I5 and operatively connected for rotation of the screw by a gear 21.. The pinion 25 is made somewhat elongated to allow for the length of movement which may be imparted to the screw by the piston l6.

For rapid positioning movements, such as when the set-up of the machine is to be changed, means have been provided for rotating the pinion 25 by power and this includes a hydraulic motor 28 which is directly connected for rotation of the shaft 26 by gearing 29.

It will thus be seen that the nut l4 and attached wheel slide may be shifted hydraulically to a limited extent, or the screw 15 may be rotated either manually or by power to superimpose an adjustment upon the Wheel slide independently of the hydraulic actuating means.

The hydraulic actuating means are utilized for effecting an automatic infeed grinding cycle in which the grinding wheel slide is advanced from a return position first at a rapid traverse rate, then at a feed rate, followed by a dwell to allow time for the grinding wheel to round up the work. The wheel slide is returned at a fast rate all the way to its return position. This cycle is initiated by a reversing valve 30 which is adapted to be hydraulically positioned in either one of two positions by a pilot valve 3| which has a plunger 32 that may be manually positioned by a control lever 33. This valve has a pressure port 34, a pair of

exhaust ports

35 and 36, and a control port 31 which is connected by channel 38 to the right hand end of the valve housing 30. The valve 3| has a second control port 39 which is connected by channel 40 to the left hand end of the valve housing 30. When the plunger 32 is manually moved downward from its stop or return position to the position in which it is shown in Figure 15 the port 39 is connected to the pressure port 34 and the port 31 is connected to the exhaust port 36 whereby the valve plunger 4| in valve 30-is shifted toward the right.

This results in the annular groove 42 interconnecting pressure port 43 with port 44 whereby the fluid flows through channel 45 to port 46 of the infeed cylinder. 7 The cylinder head 18 has a longitudinally extending groove 41 formed therein which is always in registry with the port 46 and which terminates in a radial port 48, Figure 13. When the piston I 6 is in its return position it positions the taper ended valve member 49 in position to close port 48 but aligns an annular groove 48' with the port whereby the fluid flows through

drilled passages

48a and 48b, opening check valve 480. The fluid then continues through radial passage 48d and groove 48c to chamber 49'. It then passes through an interdrilled passage by way of opening 5| to the cylinder l1 to start the piston is moving at a slow rate.

As the piston moves it releases the valve member 49 which is caused to follow up the movement of the piston by a spring 52 and thereby open port 48, which automatically accelerates the piston. At the same time the fluid in cylinder 23 is escaping through the interdrilled piston rod 24 and channel 53 to port 54 in a deceleration valve block 55.

This valve block has a piston 56 which is connected to a valve piston 51 that is slidably mounted in a valve housing 58. This valve housing is closed at one end and has a port 59 which is connected by a branch line 60 to channel 38. When the cycle is started, theline 60 and channel 38 are connected to reservoir by actuation of the valve 32 to its running position which leaves the plungers in their shifted left position, In this position the port 54 has an unrestricted connection to a channel 6| which terminates inport 62 of valve 30. Port 62 is connected by the groove 63 to the exhaust port 64.

There is thus a free escape of fluid from the cylinder 23 to reservoir, permitting unrestricted movement of the wheel slide at a fast rate.

The unrestricted connection between the port 54 and the channel 5| is by way of annular groove 65, radial ports 66, and annular groove 69 in valve plunger 56 which is he position to effect connection to port 10 when the plunger 56 is in its shifted left position. As the screw l5 moves toward the left it rotates a lever 1i pivoted at 12 by engagement with the end 13 whereby the opposite end 14 moves the plunger 55 toward the right. As it continues, the tapered spool 15 closes the ports 66, thereby decelerating the cross slide. When the ports are closed, the plunger 51 is fired, pulling the plunger 56 with it to the right which thereby registers the groove 61 with the ports 66.

The fluid now flows from the port 54 to port 10 through groove 65, radial ports 66, interdrilled passage 68 and groove 69 to port 16, permitting further movement of-the lead screw which is now limited by a control cam to be more fully described.

The plunger 56 is fired by enlarged central spool 16 which moves to theright, closing pressure port 11 and then opening it. As soon as it opens, the pressure differential created by the fluid pressure acting on the enlarged central spool and the smaller end spool completes the shifting of the plunger to the position shown.

This connects pressure from port 11 to port 18 which is connected by channel 19 to the port of a feed cylinder 8|. The other end of the cylinder has a. port 82 that is connected by channel 83 in parallel to a check valve 84 and a feed rate control valve 85. It will be obvious that the check valve is so directioned that it will close under pressure of the exhaust flow from cylinder 8| whereby the fluid is forced to pass through the throttle valve 85. The output of these two valves is connected by channel 86 to port 81 of valve 58 which is in a position whereby the port 81 is connected to an exhaust port 86.

The cylinder 8| contains a feed piston 89 upon which is formed rack teeth 90 for rotating a pinpivoted at I2 in the same manner as the lever II and the lever 95 has one end 96 which is engageable by the endof the screw I5, and at the other end carries a roller 91 which rides on the cam 94. At the beginning of a feed cycle the piston 89 is at the upper end of the cylinder 9I as viewed in Figure 14 and the cam 94 is necessarily down since it moves in a direction opposite to the piston whereby at the beginning of the feed stroke the roller 91 engages the upper end of the inclined cam surface.

In other words, when the screw is shifted to the left by the pressure in cylinder I! the movement continues at a fast rate until the screw engages the upper end of the lever 96 and since the other end of the lever is held against rotation by the cam 94 the rapidtraverse movement must necessarily stop. Any further movement after that is controlled by the piston 89 as it moves downward, correspondingly moving the cam 94 upward. The rate of the piston movement 89 is controlled by the throttle valve 85 whereby variable feed rates may be obtained.

The pinion 9| is mounted on a shaft 98 and this shaft carries a trip lever 99 which is rotated in a clockwise'direction by downward movement of the piston 89. As the piston reaches the end of its stroke, corresponding to the end of the infeeding movement, the trip lever 99 shifts a trip valve plunger I which valve acts as a pilot valve to reverse and return the grinding wheel slide. The pilot valve has a pressure port IN and the plunger has an enlarged. central spool I02 which is movable relative to the pressure port where- 0 of an interlock valve III.

The interlock valve is for the purpose of preventing operation of the table traversing mechanism during an infeed cycle and it is the usual practice to maintain such an interlock throughout the cycle. In this machine means are provided whereby the table traverse control is locked against actuation during actual infeeding movement but after the infeed has been completed it is desirable at times to effect a small reciprocation of the table in order to put a better finish on the work and therefore the interlock valve is so connected that it will release the table traverse control lever after the infeed movement has been completed.

To this end the reference numeral II2 indicates a table traverse control valve having a pressure port II3, a pair of exhaust ports H4 and I I5 and a pair of control ports H6 and II! which are connected by channels 8 and H9 to opposite ends of a table start and stop control valve I20. This valve may be connected in any suitable manner for starting and stopping table traverse and since the manner of connection forms no part of the present invention further description is not believed to be necessary. The valve II2 has another port I2l which is connected by channel I22 to port I23 of the interlock valve. The port I2I is located at one end of the valve whereby admission of pressure to this port will shift the valve plunger I I2 upward as viewed in Figure to a stop position. In this position pressure .will be connected to shift the plunger I24 of valve I to a stop position and thereby stop the table traverse.

The plunger I 25 of the interlock valve is therefore in its right hand position during the infeeding movement whereby the port I23 is connected by the annular groove I26 to a pressure port I21. When pressure is connected to channel I04, however, as previously described, pressure fluid immediately enters the port I I0 and shifts the plunger I25 to the left whereby the port I23 be- I comes connected to a port I28.

This port is connected through channel I 29 and interconnected ports I30 and I3I of a valve I32 to the reservoir line I33. This releases the table traverse control valve whereby the plunger may be shifted if desired to efiect traverse of the table. This table traverse can only be utilized during the dwell after the infeed movement has been completed and the length of time of this dwell is determined by the delay valve I08 through which fluid has been slowly flowing into channel I34 to port I35 of reverse valve I06. As

the pressure builds up plunger I01 will shift to the left and eventually effect interconnection of pggts I36 and I3'I by means of the annular groove The port I3'I is a pressure port and therefore when the interconnection has been made fluid pressure will flow through port I38 and channel I38 to port I39 of valv I32. It will be noted that this port is connected through the annular groove I40 to port I4I having a chamiel I42 leading to port I43 located in the lower end of the 40 start and stop control valve 3|. Pressure entering port I43 will shift the plunger 32 upward to a reverse position whereby the pressure port 34 becomes connected to port 31 and thereby to channel 38 while port 39 will be disconnected from the pressure port 34 and interconnected to the exhaust port 35.

Since the

channels

38 and 40 are connected to opposite ends of control valve 30 and since the pressure and exhaust connections are now reversed the plunger 4I will be shifted to its left hand position. This will result in the cylinder I! being connected to exhaust through the interconnection of ports 44 and I44, the latter being connected to the return line I45. At the same time port 62 will be disconnected from'the exhaust port 44 and connected to port. 43 whereby fluid pressure will enter channel GI and flow through port I0 of valve 55, annular groove 69, and check valve 69' to line 53 and thereby cause retraction of 131;; wheelhead by supplying fiuid to the cylinder It will be noted that the channel 38 which was connected to pressure upon shifting of the infeed control valve 32 has branch connections to port 59 of valve 58 and to port I46 of the pilot valve I 00. At the moment that pressure is admitted to these ports the plunger 51 could not be shifted on account of the lever connection with the lead screw I5 and the plunger I00 could not be shifted on account of the trip lever being connected to the 'piston 89 which is still held in the position shown by hydraulic pressure. Therefore, there is a slight delay until the lead screw starts to move toward the right whereby the fluid pressure entering port 59 may cause the plunger 51 and connected plunger 56- to follow up the movement throug 1 the leverfll until the plunger 51 has reverse the connections whereby the port 18 becomes connected to the exhaust port I41 and the pressure port 11 is interconnected to port 81. This reverses the pressure conditions in cylinder 8|, the piston 89 now moving upward at a rapid rate because of no restrictions on the outflow and no restrictions on the inflow because the check valve 84 will open and bypass the throttle valve 85.

As the piston moves the shaft 98 will be rotated, thereby rotating the trip lever in a counterclockwise direction, permitting the pressure enterin the port I46 to shift the plunger I downward and effect connection of pressure port IOI with port I48. This will cause fluid pressure to flow through channel I49 to port I50 of valve I06.

This will shift the plunger I01 back to the position shown, the fluid escaping from the other end of the cylinder through check valve I09. The port I50 has an annular groove portion whereby the fluid may continue through line II to port I52 of the interlock valve, thereby returning the plunger I to its right hand position and thus connect pressure to the table interlock control lever. I

As the piston I6 completes its return movement it engages the end of plunger .49 shifting the same toward the right, thereby restricting the escape of fluid through port 48 which produces a dashpot effect and causes a fast deceleration of the piston to a stop. This completes the operation of an automatic infeed cycle.

As previously mentioned-the pinionv 25 may be rotated by either manually operable means or power operable means for positioning purposes.

The manually operable means'is shown more particularly in Figure 2 to which reference may now be had. This comprises a hand wheel I53 having a bore I54 by which it is fitted against a shoulder I55 of an annular member I56 which has an elongated hub I51 by which the member I56 may be keyed at I58 to a sleeve I59. The sleeve I59 has a'sun gear I60 formed on one end and a second gear I6I secured to the other end for rotation therewith as by the key I58 which is made sufliciently long for this purpose. The hand wheel is fastened to thememberv I56 by an annular ring I62 which clamps the hand wheel against the shoulder I55, the parts being fastened together as by screws I63. The ring I62 also serves to hold in a depression I64 formed in the face of the member I56 a planetary gear carrier I 64-which is normally secured by a locking pin I6 5"t-o the member I 56 for rotation therewith. A stud'shaft I66 is securedin the wall of the housing I61 and projects therefrom to support these parts? An inner'sleeve .I68 is journaled on the shaft and the outer sleeve I59 and the parts keyed thereto are capable of rotation relative to the inner sleeve. A drive gear I69 is formed integral with one end of the sleeve I69 while on the other end a second sun gear I10 is slidably splined for relative movement into and out of engagement The hub is in the form of a tubular member. Attached to the end of the fixed stud shaft I86 is a detent mechanism for holding the gear I10 in either one of two positions. This comprises a cage I15 in which is mounted spring pressed detent balls I16 for selective engagement with annular grooves I11 and I18 formed interlorly of the tubular hub. When the locking pin I65 is engaged, rotation of the hand wheel I53 as by means of the handle I19 attached thereto, will effect rotation of all of the parts as a unit whereby one rotation of the hand wheel will effect one rotation of the drive gear I69. This gear is connected by an intermediate idler gear I in 1-1 ratio with a gear I 8| which is attached to the end of a shaft I82 supported by anti-friction bearlngs I83 in a fixed part I84 of the bed.

The shaft I82, it will be noted, is a tubular shaft and has a gear I85, Figure 14, connected thereto which intermeshes with a gear I86 forming one member of a hydraulically operated clutch mechanism. The other member I81, Figure 10, carries a fluid operable plunger I88 which has a beveled end I89, Figure 11, by which it may be forced by hydraulic pressure into engagement with a notch I90 formed in the periphery of the hub I9'I of the gear I86 for interconnecting the parts for joint rotation. The member I81 is connected by a coupling I92 to the shaft 26. Hydraulic pressure is normally connected to the clutch whereby it will be seen that rotation of the hand wheel will effect rotation of the shaft 26 in a 1-2 ratio because the gears I85 and I66 are in a 1-2 ratio.

A feed back mechanism has been provided for indicating the amount of movement effected upon rotation of the screw and this is effective regardless of whether the movement is effected by either the manual or power means; in other words, regardless of whether the hydraulic clutch is connected or disconnected. This is because the drive gear I93 which is utilized for this purpose is connected for rotation by the shaft 26 at all times. This gear is connected by an intermediate gear couplet, indicated generally by the reference numeral I94 to a gear I95 attached to the end of a shaft I96 that passes through the tubular shaft I82. The shaft I96 is connected by bevel gearing I91 to a vertical shaft I98, which, as shown in Figure 2, terminates in a bevel pinion I99. This pinion meshes with bevel gear teeth 200 formed integral with an annular ring 20I which is journaled for rotation on the bearing 202 constituting part of the fixed housing I61. The housing I61 carries a fixed mark 203 as shown in Figure 3 for cooperation with graduation marks 204 formed on an annular ring 205 which serves to carry one or more markers 206. The graduated ring 205 is supported on the member 20I for relative movement with respect thereto and may be secured for joint rotation therewith by a locking screw 201. The ring 205 has a T-slot 208 formed therein as shown in Figure 4 by means of which the markers 206 may be clamped in various positions about the ring. Although this scale will not serve as a micrometrical setting of the grinding wheel, it is particularly useful when grinding multiple diameter work because by properly setting the markers 206 it indicates to the operator the ap proximate position of the wheel for each diameter and saves time in positioning the wheel whereas otherwise the operator would have to feel his way, so to speak.

The means for micrometrically setting the attached to a fixed part of the housing I61.

of a threaded bore 2I3 in which is mounted an adjustable set screw 2 I4. This set screw is adapted to abut a removable stop member 2I5- which is pivotally supported on a shaft 2I6 as shown in Figure '1, journaled in a support 2I1 that is The stop 2 I 5 is secured to the shaft for rotation therewith, and the shaft is provided with a toothed portion 2I8 which is engageable by a spring pressed detent 2I9 for holding the stop in an operative position or in an inoperative position. The shaft 2I6 is also provided with an operating nob 22D .and the detent 2I9 has an operating knob 22I whereby the detent may be manually released during rotation of the shaft by the knob 220. In order to eliminate adjustment of the dog 2 means are provided whereby the handwheel may be rotated in either direction relative to the drive gear I69 and this is efiected by withdrawing the connecting plunger I65 and rotating the carrier I56 whereby the planetary gears are caused to move about the sun gears.

The sun gear I will be held against rotation due to the load on gear I69 whereby the wheel and dog carried thereby will be slowly moved relative to the stop member 2I5.

with ten evenly spaced holes 222 as shown in Figure 5 for receiving the locking pin I65 and these holes are spaced apart in such relation as to permit rotation of the hand wheel an amount equivalent to .0001" on the work diameter.

Means have been provided for easing the load on the hand Wheel and making it easy to turn and this includes the hydraulic motor 28 and a control valve 223 therefor, which is frictionally operated by the shaft I82. In other words, this shaft has a depending lever 224, Figure 14, which surrounds the shaft and is connected to it by sufficient friction that it will move the valve plunger 225 in accordance with direction of rotation of the shaft and then will slip relative to the shaft. The valve 223 has a pressure port 226 and a pair of

control ports

221 and 228 which .are alternately connectable to the pressure port in accordancewith the direction of shaft rotation. These ports are connected by

channels

229 and 230 to ports 23I and 232 of a rapid traverse control valve 2 33.

The ports 23I and 232 normally register with valve plunger 235 because this plunger is normally held in the position shown by a pair of centralizing sleeves 231 mounted on the reduced ends of the plunger. Interdrilled passages 238 and 239 in the plunger connect the annular grooves 234 v and 235 to annular grooves 240 and 24I. Ports The member I56 which is integral with the wheel is provided The

channels

254 and 255 extend to the motor 28 whereby a hydraulic urge or pressure may be exerted on the motor tending to cause rotation thereof. Attention is invited to the fact that the pressure port 226 of valve 223 is connected by a channel'256 to the outlet of a relief valve 251 and to the inlet of a second relief valve 258.

In other words, the line 256 is supplied with pressure from the exhaust of relief valve 251 but the pressure is determined by the relief valve 258 which, in turn, exhausts through channel 259 to a third relief valve 268 having an exhaust 26I that terminates in a reservoir 262. The pressure .in channel 256 is equal to the combined values of the settings of the two relief valves 258 and 26D whichin the present instance wold be equal to about 60 pounds pressure. The relief valve 251 is set at a much higher value. The pressure in channel 263 which is controlled by the combined values of all three

relief valves

251, 258 and and 260 is equal to approximately 260 pounds.

The pressure in line 256 is-so adjusted by the relife valvethat this pressure acting on the motor 28 is not sufficient to actually effect rotation of the shaft 26 but is still suflicient to counteract most of the torque necessary to effect rotation thereof whereby only a slight additional torque necessary to rotate the handwheel andis autothe annular grooves 234 and 235 formed in a matically applied in the correct direction in accordance with the direction of rotation of the hand wheel.

The'rapid traverse control valve is utilized when it is desired toeifect quick positioning movements or to change the zone of movement of the wheel head during cyclic operation, especially those that would require a large number of rotationsof .thehandwheel to efiect. Since the pressure in channel 256 is insufiicient to effect rotation of the motor 28 it is necessary to use a higher pressure such as that which exists in channel 253. Fluid is supplied to this channel by a pump 264 which is driven by the pulley 265 which may be operatively connected to a suitable electric motor for actuation. 'Th pump 264 has an intake channel 266 through which fluid is withdrawn from the reservoir 262.

It will-be noted that the channel 263 extends through the control valve I20, the valve III and the valve I32 as shown in the hydraulic diagram in Figure 15 and continued in the hydraulic dia gram shown in Figure 14. The shifting of the rapid traverse control valve is effected hydraulically under the control ofa pilot valve 261, Fi ure 12, which has a plunger 268 operatively connected to the control lever 269, Figure 9.

This control lever is held in a neutral position by a pair of spring pressed plungers 210 and 2H which are positioned on opposite sides of the.

shaft 212. They also serve to return the lever automatically to its neutral position when it is released. The shaft 212 has a crank arm 213 which is operatively connected to the plunger 268. The channel 263 is connected to the pressure port 214 of the valve 261 and also to a pressure port 215 of the rapid traverse control valve 236. The pilot valve has a pair of

ports

216 and 211 which are connected by

channels

218 and 219 to opposite ends ofthe rapid traverse control valve. The pilot valve also has a pair of exhaust ports 288 and28l whereby when the plunger 268 is shifted the pressure port 214 is alternatively connected to either port 216 or port 211 while the remaining port is connected to one of the exhaust ports 280-28I. In addition, the pilot valve plunger 268 has a pair of

annular grooves

282 and 283, one of which is in registry with the pressure port 214 and the other of which is in registry with a port 284 when the plunger is in a central Dosition.

These two annular grooves are interconnected by an interdrilled channel 285 whereby the port 288 is supplied with pressure when the p1un8er,is in a central position. The port 284 is connected by a channel 288 to the previously described hydraulic clutch which interconnects the hand wheel to the shaft 28. This serves as the means for normally maintaining engagement of the clutch but should the pilot valve 288 be shifted either to the right or to the left the port28l is connected to either the exhaust port 28I or to passes to reverse the operation of the motor after the nut has reached the end of the lead screw. It will b noted that the screw l5 has limited axial movement and therefore has two positions,

which means the end of the screw has two positions. If the dogs are set for one position and then the screw is shifted to its other position, the,

another exhaust port 281. This relieves the pres- 292 which is always in communication with'the' groove 29! during rotation. The gear I86 carries a first radial passage 293 which is adapted to register with the radial passage 282 and a second radial passage 298 interconnected with the first by bore 295 that is adapted to register with a second radial passage 288 that is'in communication with the fluid operable plunger I88. I The radial passages in one member are only in register with the radial passages in the other member in one position, that is when the plunger I88 is opposite the notch I98. Otherwise, if the clutch is disconnected and the ports are out of register the pressure to the plunger is cut of! and prevents it being applied and causing friction during relative rotation to bring the plunger opposite the groove.

The safety valve 248 is provided for the purpose of preventing the nut I4 from overtraveling the end of the screw I5 and causing damage to the screw threads or adjacent parts. This might happen when the operator uses the rapid traverse and fails to estimate correctly the speed of movement of the slide.

To prevent such overtravel by the motor 28 a trip rod 291 is slidably mounted in the bed and provided at opposite ends with adjustable dogs 288 which are in the path of a projecting abutment 299 of the cross slide. Engagement of the abutment with either dog will cause axial movement of the trip rod. A crank arm 888 is pivotally supported at I for transmitting the motion from the trip rod to the valve plunger 25!. It will be obviou that when this plunger is pulled or pushed out of its center position that one of the lines to the motor will be blocked and it is so arranged that the'line blocked will be the return line from the motor 28.

Assuming the line 2 to be under pressure, then the line 255 will be the return line and the one blocked. In order to back the parts off, the line 245 must now be connected to pressure and the line 2 connected to exhaust in order to reverse the direction of rotation of the motor 28. Since the connection between

line

245 and 255 is blocked by the valve 25I, a check valve 302 is connected to form a bypass through which fluid may flow to the motor. Thus, the check valves 302 form bysafety valve would be effective for one end but ineifective to prevent Jamming at the other end. To compensate for this the pivot SM is mounted in the end of a plunger 308 which is held in one position by a spring 304 and which corresponds to the return position of piston I6. When pressure is admitted to this piston through line 45, a branch connection is made through line 305 to advance the plunger 803 and thereby the pivot 8M a sufficient amount to compensate for the change in position of the screw.

There has thus been provided an improved infeed mechanism for a grinding machine having manual and automatic control and with which has been incorporated a rapid traverse mechanism having suitable safety interlocks with the remaining parts of the mechanism.

What is claimed is:

1. In a grinding machine having a work support and a grinding wheel support, the combination of means for effecting relative movement of the grinding wheel support relative to the work support including a feed screw operatively connected to the grinding wheel support, a piston formed on one end of said screw for advancing the grinding wheel support at a, rapid rate, a positive stop means including a cam for limiting movement for driving the cam to effect a feeding movement of the support, and means responsive to movement of the screw for energizing said power operable means.

2. In a grinding machine having a, work support and a grinding wheel support, the combination of means for effecting relative movement of the grinding wheel support relative to the work support including a feed screw operatively connected to the grinding wheel support, a piston formed on one end of said screw for advancing the grinding wheel support at a rapid rate, a positive stop means including a cam'for limiting movement of the screw by said piston, power operable means for driving the came to effect a feeding movement of the support, means responsive to movement of the screw for energizing said power operable means, and means for rotating said screw to change the position of the support relative to the piston.

3. In a grinding machine having a work support and a grinding wheel support, the combination of means for advancing the grinding wheel suport at a fast rate and a slow feeding rate including a rotatable screw operatively connected to the grinding wheel support, power operable means for axially shifting said screw to eifect the fast movement, positive means for limiting the extent of said fast movement including a, feed cam, power operable means for actuating said cam to control a feeding movement of said support under the power of said power operable means, and means operable by the screw simultaneously with engagement of said positive stop means to initiate movement of the feed cam.

4. In a grinding machine having a worksupport and a grinding wheel support, the combination of means for advancing the grinding wheel support at a fast rate and a slow feeding rate ineluding a rotatable screw operatively connected to the grinding wheel support, power operable means for axially shifting said screw to effect the fast movement, positive means for limiting the extentof said fast movement including a feed cam, power operable means for actuating said cam to control a feeding, movement of said support under the power of said power operable means. means operable by the screw simultaneously with engagement of said positive stop means to initiate movement of the feed cam, and means for rotating said screw to change the zone of movement of the grinding wheel support relative to the zone of movement of the screw.

5. In a grinding machine having a work support and a grinding wheel support, the combination of a power operable infeed mechanism including a cross feed screw, a feed nut operatively connecting the screw to the grinding wheel support, power operable means for moving the screw axially to effect a grinding cycle including rapid approach, feed and rapid retraction, comprising a fluid operable piston for effecting the rapid ap proach, a positive stop means for limiting the rapid movement of the screw, said stop means including a feed cam movable at a slow rate to permit additional movement of said screw by said piston at a feeding rate, and an'additional piston for effecting rapid retraction of said slide.

6. In a grinding'machine having a bed, a work support and a grinding wheel support mounted thereon, the combination of means for feeding the grinding wheel support including a cylinder mounted in the bed of the machine, a piston slidably mounted in said cylinder and operatively connected to said support, an adjustable cylinder head mounted in said cylinder, fluid operable means for maintaining said piston in engagement with saidcylinder head for determining the retracted' position of the grinding wheel support, and means to longitudinally adjust said cylinder head to change said retracted position.

7. In a grinding machine having a bed, a work support and a grinding wheel support mounted on said bed for relative movement toward and from one another, the combination of a fluid operable pistonoperatively connected for effecting said movement, a cylinder containing said piston, a cylinder head mounted in one end of said cylinder, means to admit pressure to the piston through said cylinder head, throttling means in said cylinder head operable by the piston for throttling the escape of fluid from the cylinder during return of the piston to decelerate and stop it, means to bypass the throttling means to start the piston on its advance stroke, means responsive to advance of the piston to render said throttling means effective and said bypass means ineffective whereby said throttling means will control the rate of acceleration of the piston on' its advance stroke.

8.'In a grinding machine having a work sup port and a grinding wheel support, the combination of means for effecting advance and retraction of the grinding wheel support relative to the work support including a first fluid operable piston for effecting said advance, a second fluid operable piston for effecting said retraction, a source of pressure, a separate channel for each piston, valve means for alternately connecting said chaimels to said source of pressure to effect reciprocation of the support, means in each of said channels to control the rate of acceleration of the respective pistons, and additional means 7 in each of said channels for controlling the rate of deceleration of said pistons.

9. In a grinding machine having a work support and a grinding wheel support, the combination of means for effecting advance and retraction of the grinding wheel support relative to the work support including a first fluid operable piston for efiecting said advance, a second fluid operable piston for effecting said retraction, a source of pressure, a separate channel for each piston, valve means for alternately connecting said channels to said source of pressure to effect reciprocation of the support, means in each of said channels to control the rate of acceleration of the respective pistons, additional means in each of said channels for controlling the rate of deceleration of said pistons, a pilot valve for controlling the shifting of said valve means, and a manually operable control lever for said pilot valve.

10. In a grinding machine having a work support and a grinding wheel support, the combination of means for effecting relative adjustment between the supports including a screw and nut mechanism, one of which is carried by the movable support, power operable means for reciprocating said screw to effect an infeed grinding cycle, a manually operable hand wheel, a fluid operable clutch for connecting said hand wheel for rotation of said screw to effect adjustment of said support, a fluid operable motor operatively connected for rotation of said screw for effecting rapid adjustments of said support, a reversing control valve for said motor, a pilot valve having a source of fluidpressure connected thereto for controlling the shifting of said reversing valve and having a neutral position for connecting said source of pressure to the fluid operable clutch, manually operable means for shifting said pilot valve, and means responsive to movement of the pilot valve from its neutral position to disconnect pressure from said clutch and connect pressure to shift the reversing valve from its neutral position in accordance with the direction of shifting of the pilot valve.

11. In a grinding machine having a work support and a grinding wheel support, the combination of means for effecting relative adjustment between said supports including a feed screw and a nut, one of which is carried by the movable support, means for axially shifting said screw between a forward and return position, a rapid traverse motor for rotating said screw, means to effect operation of said motor including a hydraulic control circuit, a safety valve in said circuit, a pivoted lever trip operable by the movable support for stopping said motor when the nut has reached either end of the screw, and automatically operable means for shifting the pivot point of said lever to compensate for the axial shift of said screw.

12. In a grinding machine having a work support and a grinding wheel support, the combination of means for shifting one of saidsupports relative to the other including a cross feed screw, means for effecting-rotation of said screw including a hand wheel, a 'sleeve having a drive gear on one end operatively connected to said screw, a slidable gear splined on the other end, a'second gear rotatably mounted on the sleeve in adjacent relation to the slidable gear, a carrier plate supported by the hand wheel andcarrying a pair of gears in mesh with the respective adjacent gears, means to connect the plate to the hand wheel whereby all of said parts rotate as a unit to drive said drive gear, said connecting means including a retractable pin for effecting rotation of the plate independent of the hand wheel to effect slow rotation of the drive gear, and means to withdraw said slidable gear out of mesh with its co-acting gears to permit idle rotation of the hand wheel, and an adjustable stop dogcarried by the hand wheel for engaging a removable stop to limit the infeed movement effected by the hand wheel.

13. In a grinding machine having a work support and a grinding wheel support, the combination of means for shifting one of said supports relative to the other including a cross feed screw,

; means for effecting rotation of said screw including a hand wheel, a sleeve having a drive gear on one end operatively connected to said screw, a slidable gear splined on the other end, a second gear rotatably mounted on the sleeve in adjacent relation to the slidable gear, a carrier plate supported by'the hand wheel and carrying a pair of gears in mesh with the respective adjacent gears, means to connect the plate to the hand wheel whereby all of said parts rotate as a unit to drive said drive gear, said connecting means including a retractable pin for eifecting rotation of the plate independent of the hand wheel to effect slow rotation of the drive gear, and means to withdraw said slidable gear out of mesh with its co-acting gears to permit idle rotation of the hand wheel, an adjustable stop dog carried by the hand wheel for engaging a removable stop to limit the infeed movement effected by the hand wheel, and other dogs attachable to the hand wheel for successive engagement with said stop for multiple diameter grinding purposes. f

14. In a grinding machine having a work support and a grinding wheel support, the combination with a feed screw operatively connected to the grinding wheel support, of a fluid operable motor operatively connected for rotation of the screw, a source of low pressure and a source of relatively higher pressure, a control valve normally connecting said source of low pressure to the motor, a manual control for rotating said screw,

means responsive to the direction of rotation ofsaid screw for controlling the position of said valve and thereby maintaining the application of said low pressure to the motor in a direction to cause the motor to act as a booster motor during manual rotation of the screw, a second control for connecting the source of higher pressure to the motor and disconnecting saidsource of lower pressure to effect rotation of said screw at a fast rate to effect rapid traverse shifting of the movable support. s

15. In a grinding machine having a reciprocable work table and a grinding wheel support movable toward and from the table, the combination of transmission and control means including a start and stop control lever for the table, an infeed start and stop control lever for the grinding wheel support, means to shift said infeed lever to effect an automatic infeed cycle of the grinding wheel support at rapid traverse and feed movements, a feed motor for effecting said feeding movement, a piston for returning the support, a reverse valve, a pilot trip operable by the feed motor for connecting pressure for shifting said reverse valve, means to delay said shifting, and means responsive to the completion of said shifting to shift said infeed start and stop lever to its return position, means responsive to the return of said lever to actuate a reverse valve for the return piston.

16. In a grinding machine having a reciprocable work table and a grinding wheel support movable toward and from the table, the combination of transmission and control means including a start and stop control lever for the table, an infeed start and stop control lever for the grinding wheel support, means to shift said infeed lever to effect an automatic infeed cycle of the grinding wheel support at rapid traverse and feed movements, a feed motor for effecting said feeding movement, a piston for returning the support, a reverse valve, a pilot trip operable by the feed motor for connecting pressure for shifting said reverse valve, means to delay said shifting and create a dwell; means responsive to the completion of said shifting to shift said infeed start and stop lever to its return position, means responsive to the return of said lever to actuate a reverse valve for the return piston, an interlock valve for connecting pressure to hold the table control lever in a stop position, and means responsive to said trip operable pilot for shifting said valve to release the pressure on said lever during dwell of the grinding wheel support whereby the table may be reciprocated during the dwell.

JACOB DECKER. ALBERT D. C. STUCKEY.