US2367758A - Grinding machine - Google Patents

Description

Jan. 23, 1945. J. DECKER ETAL GRINDING MACHINE 2 Sheets-Sheet 1 Original Filed June 2. 1939 Jan. 23, 1945.

J. DECKER ET AL GRINDING MACHINE Original Filed June '2. 1959 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

v I tools and y to improved transmission and ion of o n copencling applii'iled June 2, 1939, new ad August :26,

e ocgects or" tis invention is to provide t e traversing mechanism and conlo; a cylindrical grinding machine.-

object of this invention is to provide means for interlocking the sraversing and the info-ed mechanism ofa cylina3 machine so that undesirable siiier object of the invention is the provision of improved means for accurately controlihe extent of movement of the grinding machine table in a given direction and the periods of dwell and accelerated reversal whereby accurate terminal grinding may be most advantageously effected,

A further object of the invention is the provlsion of an improved manner of in'tercoupling and interconnecting the several hydraulically and mechanically actuaole control elements for a grinding machine table or the like to insure proper sequential operation of the controls and prevent possibility of improper stalling of the table or the mechanically actuated portions of the control.

iher 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 l is a front elevation of a grinding machine embodying the principles of this invention.

Figure 2 is a diagrammatic view of the hydraulic actuating circuit and controls therefor.

Figure 3 is an enlarged fragmentary sectional view of one of the terminal portions of the reversing valve mechanism.

Referring to Figures 1 and 2 of the drawings the reference numeral ill indicates the bed or main support of the grinding machine upon the top of which are formed guideways as at M, as shown in Figure l, for supporting and guiding the work table is. This table is provided with a 1 for cylindrical grinding moconventional headstock, indicated generally by the reference numeral iii, including a driving motor in addition, tailstoclr ii is provided, controllabl lay levers and v A grinding wheel is rotatably journaled on e, wheelhead which is guided on the movement coward and from the worlz, controllahle by lever .253 while throttle lrnohs Edda-rid Bill may he set to control hydraulic wheel head movements as described in Patent No. 2,254,092. The table is is providedv/lth depending brackets fihwhich support a cylinder is for movement with the table. A piston oil is contained within the cylinder and connected by piston rods ill and S2 to fixed aprons mounted on opposite ends of the bed in a conventional manner.

Thus, with the piston rod and piston fixed, the admission of hydraulic pressure to opposite ends of the cylinder is effected through the piston rods which are made hollow and provided with cross bores 33 adjacent opposite sides or the piston.

The depending brackets 22', also carry a rack 3d which serves as means for driving the table manually through the hand wheel 3%. This handwheel is attached to the end of a pinion 3%. which meshes with a spur gear ill, the spur gear having a co-axial pinion which drives the rack through an intermediat idler so. In order to prevent rotation of the hand wheel during power actuation of the slide, a piston so slidably mounted in a cylinder 55. is axially aligned with the pinion 38 for shifting the same the left, as

viewed in Figure 2, out of engagement with the idler gear 8%.

Power traverse of the tabl is controlled by a start and stop control lever. d2 which is mounted on the front of the machine as shown in Figure 1 and integrally connected to a. start and stop control valve which has a fixed sleeve 3 and a rotatable plunger Ml. This plunger has various control poi-tings throughout its length, and to facilitate understanding of the operation of this valve, a series of sections through the valve are shown in Figure 2 and indicated by the reference numerals 35 to 52 inclusive, it being understood that the outside portion is all part of the fixed sleeve and that the center portion in each sectional view is all part of the valve plunger and integral with the bed for I only two positions. the pressure shown in sections 88 and 88 of this valve. These sections also have ports 8'! and 88 which are connected to the pressure supply line 88.

This line is supplied with fluid pressure by a pump 88, which has an intake 8| through which fluid is withdrawn from a reservoir 82. It will be noted that in the stop position of the valv 48 both ports 88 and 88 are connected to the pump whereby pump pressure will existin opposite ends of the cylinder 29 maintaining the same full-of oil, thereby preventing admission of air to the system. but at the same time not interfering with manual traverse of the table by the wheel 88 since the oil in one end of the cylinder will be bypassed through the valve into the other end whenever the hand wheel is rotated.

when the lever 82 is thrown to its running p sition the arcuate grooves 88 and 88 will connect ports 88 and 88 to ports 88 and 88 respectively and thereby through channels 81 and 88 to ports 88 and 18 of a reversing valve, indicated generally by the reference numeral I I The reversing valve has a plunger I2 which is power shifted from one end'of the valve housing to the other by hydraulic means, which is controlled by a pilot valve, indicated generally by the reference numeral l8. The pilot valve has a plunger 18 which is mechanically connected by a crank I8 to the trip rod 18, this rod terminating in the trip lever 11 adjacent the side of the table as indicated in Figure 1.

Since the plunger I: of the reversing valve has port 18 or this all times toeither valve will be connected at annular grooves I8 port 88 or I8 by means of and 88 respectively.

With the plunger 12 in the position shown, ports I8 and 88 are interconnected, and fluid pressure will flow through channel 81, port 88, groove 88, port 88 and channel 88 to the left end of cylinder 28, causing movement of the table I8 toward the left. Fluid from the other end of the cylinder will return through channel 88, port 88, move 88, port 88, channel 88 to port 18 of the reversing valve. The latter port is interconnected by the annular groove 88 to exhaust port 8|. Should the plunger 12 be shifted upward as viewed in Figure 2 to its other position the pressure port I8 would be connected to port I8, and port 88 would be connected to the exhaust port 82.

The rate of table traverse is controlled by throttling the exhaust fluid from the table motor rather than throttling the inflow as is done in many cases. The traverse rate throttle valve is indicated by the reference numeral 88. Means are provided in the pilot valve for alternately connecting the exhaust ports 8| and 82 of the reversevalve with the throttle valve 88 in accordance with the direction of table movement, so that one throttle valve will serve to control the rate in both directions.

This is accomplished by connecting ports 8| and 82 to ports 84 and 85 of the pilot valve by means of channels 88 and 81 respectively, and roviding annular grooves 88 and 88 on the pilot valve plunger for alternately connecting ports 84 and 85 to port 88. ;The latter port is connected by channel 8I tothe intake port 92 of the throttle valve 83. This valve has an exhaust port 98 which is connected to the return line 94 that ,conveys the fluid back to the reservoir 82. A low pressure relief valve 95 is serially connected in the channel 94 for maintaining the system iull of oil.

a-semsa As the table nears the end of its stroke, a dog 88 suitably positioned on the table starts rotation of the trip lever I1 and thereby through the mechanical linkage previously explained starts longitudinal movement of the pilot valve plunger I8. The pilot valve has a pressure port 81, and a pair of ports 88 and 88 which are connected to opposite ends oi the reversing valve for alternately delivering pressure thereto to effect power shifting of the plunger 12. Attention is invited to the fact that the pilot valve plunger has a spool I88-which is larger in diameter than adjacent spools I8I and I82.

The spool I88 reciprocates in the enlarged bore I88 and the length or this bore determines the length of movement of the plunger I4. After the spool I88 passes pressure port 81, the pressure fluid is admitted behind the spool, while the pressure diflerential, due to greater diameter of spool I88 and bore I88 than spools I8I-I82, renders the pilot valve plunger self-actuating after it passes a mid-position.

With the pilot valve plunger 18 in the position shown in Figure 2 in which the pressure port 81 is connected to port 88, the fluid, has passed through channel I88, the lower end I88 of check valve I88, to port I81 of a tarry valve I88. This valve has a rotatably adjustable plunger I88 in the periphery of which is cut a V-shaped groove III for varying the resistance of port I81 and thereby the rate of flow through the valve to port III. 'Ihisportisconnected by channel II2 toannular groove II8 forme'd'in the sleeve of the re-.

versing valve. This groove communicates with twospacedportslllandlll.

When the pilot valve plunger 18 moves downward past its mid-position under the action of the table dog, the pressure port 81 will be connected to port 88 and fluid will flow through channel I2I, the lower end I22 ofcheck valve I28, channel I28 to port I28 of the tarry valve I28. This valve also has a rotatably adjustable plunger I21 in which is cut a V-shaped groove I28 for variably determining the resistance of port I28.

The fluid passing through this valve through channel I28 to the annular groove I28 formed. in the lower end of the reversing valve sleeve. This groove also has a pair of port I88 and I8I.

Each end of the reversing valve plunger 12 is constructed as shown in Figure 3. An annular groove I82 is cut in the periphery of the plunger to form a spool I88 of a width substantially equal to the width of ports Ill and I88, so that upon movement of the plunger from one extreme position to the other, the spools I88 will completely close ports H4 and I88 in the middle of the stroke of the plunger. A cross bore I88 is'drilled in the bottom of each groove I82 to intersect a longitudinal bore I 88.

The latter bore has an enlarged portion I88 which is threaded at the end to receive a plug I81 and thereby form a chamber in which is mounted a spring pressed ball check I88 for normally closing the end of the bore I35. The plug I81 has a small axial bore I39 formed therein whereby fluid entering the cross bore I88 and passing the ball check I88 may reach the end chamber I8. I

The manner of operation is as follows:

A table dog such as 98 rotates the trip lever 11 and thereby moves the pilot valve plunger I8 toward its mid-position. The tapered spool I42 on the pilot valve plunger gradually closes continues I asev vsa thereby restricting the flow table cylinder which results in de- When the pilot valve need or blocked by the spool movement should cease. D e moved to pr ure y of pilot valve. is provided with an ch is drilled a cross free communicae whereby fluid passing valve plunger reaches its nudi 35 are both in comgroove is? although each osed- This permits the the cylinder which is not position muons-w n in connected ciently to continue the movement of the table the mount necessary to carry the nilot valve past Us Znidposition. It will now be apparent that the spool is? on the pilot valve during movement of theiatter to'its midposition actsas means to decelerate the movement of the table.

After the pilot valve is fired by hydraulic pressure, the port through which the bleeding occurred is completely closed and the movement of the table stopped. Pressure fluid will now be connected to port 83 of the pilot valve and thereby through the tarry valve 5% to the annular groove 329 of the reversing valve. Due to the high resistance of port till the fluid will flow through port 438 and annular groove i3i2 in the reversing valve plunger to the ball check 53% which will open under pressure, thereby permitting the fluid to continue through passage its to space i li. The pressure acting in this space will cause upward movement of the reversing valve plunger 3? at a rather fast rate, which will be reducedas ports iild and ti l close.

The channel iii has a branch line 535 which is connected to the upper end iii of the check valve mt whereby upon upward shifting of the reverse valve plunger T2, the returning fluid will build up pressure in channels iii and H5 due to the resistance of the tarry valve and shift the plunger H8 of the check valve against the resistance of spring HQ and thereby uncover the exhaust port 528. Since this port is connected to the return channel 95 the fluid exhausting from the reversing valve will be returned to reservoir.

Movement through the midposition will be sustained by fluid entering port iai. After the plunger 72 passes the n'aidposition, port lSfi will gradually open again to increase the rate of movement of the plunger. At the same time the tapered spool 1159 will gradually open the &

pressure port 38 to start the return movement of the table at a gradually accelerated rate.

Thus, the pilot valve determines the deceleration of the table to stop; the time of movement oi the reverse valve plunger to its mid-position detcrniines the length of tarry of the table; an the rate of moveme t of the reverse valve plr' er from in p to its end cosi .on doter of acceleration of the tahie in s new r recticn.

E lie, n -n1- reversing the iote at other on 5 stroke the same the pilot will be moving upaard toward the position shown in 2 and when the pressu port all is connected to port fluid will flow through the space of the valve and the tarry valve tilt to the upper end of the reversing valve starting the plunger '52 on its downward movement.

Fluid from the lower end of the valve will escape through channel ltd but due to the high resistance of the throttle valve i22 the pressure will rise, opening the check valve plunger whereby the fluid will return to reservoir through channel 9%.

During power operation of the table, interlock means have been provided for. actuating the piston to disconnect the hand wheel 3%: and, by referring to section 58 of the start and stop control valve, it will he noted that the plunger nected to the cylinder ii to render the hand wheel 35 inoperative. When the plunger id is returned to a stop position the groove 5'52 will interconnect port-i l to an exhaust port W5 whereby the fluid in cylinder ll may return to reservoir and permit operative engagement of the hand wheel 35 with the table rack 34.

Means have been provided for automatically feeding the grinding wheel toward the work at the end of each stroke of the table comprising a pick feed wheel Q55, coupled in conventional manner with the wheel slidescrew and a pick feed pawl it? pivotaliy supported on the end of an oscillatable lever 558. This lever has gear teeth 559 on the periphery of its hub intermeshing with gear teeth 169 formed on the end of an oscillatable lever I6! that is pivotally supported at lo A crank H3 operatively connected to the lever 385 has a roller 28% journaled in the end thereof for engagement by a con toured surf-ace ids formed on the periphery of a piston idt.

The piston is reciprocably mounted in a cylinder 56'! which has a port 458 at one end connected by channel its to port iii] of section de of the start and stop control valve, and a second port iii in the other and connected by channel H2 to port 3'53 of section 51 of the start and stop control valve.

When the start and stop control valve is rotated to its running -position the ports H0 and H3 are connected by cross bores I14 and H5 respectively to ports lit and ill. These ports are connected by branch lines 518 and I79 to ports 99 and 98 respectively of the pilot valve whereby when these ports are alternately connected to pressure upon shifting of the pilot valve plunger, the piston E66 will be shifted first to one end of its cylinder and then to the other end of the cylinder.

pressure relief valve 338 connected thereto as shown in Figure 2 to protect the system. There is also shown a control valve 3 actuable by knob I and having extending therefrom a conduit 346 which may be coupled with conventional coolant or other-control In the position shown, conduit 3" receives actuating pressure by way of conduit I, groove N2 of the start-stop valve mechanism as indicated in the section l8 and conduit I coupleable with 58 when the start-stop or primary control valve is in running position. When this control valve is in the position shown in Figure 2, conduit I is then coupled to reservoir but by drawing out of knob 3 conduit 3 may then be coupled'to the pressure line I! by way of groove 6 so that the accessory devices may belindependently actuated when the machine is stopped.

It will further be noted that conduits it and 84 are indicated with portions extending to the right which may be utilized for actuation of the wheel feed mechanism particularly shown in our patent above referred to.

Additionally, the start-stop or primary manual control valve has a channel 329 for cowling ports in and "I to an emergency wheel reverse controlling conduit 332 whose purpose is likewise disclosed in said patent.

What is claimed is:

1. In a grinding machine having a grinding wheel, a support therefore and a work support, the combination of transmission means for eflecting relative movement between the supports including a fluid operable motor, a source of fluid pressure, a fluid shiltable reversing valve for connecting said source of pressure for alternate actuation of said motor, a pilot valve for connecting said source of pressure for alternate shifting of said reversing valve, a return channel for receiving the exhaust fluid from said motor, throttling means in said channel to regulate the rate of actuation of said motor, said pilot valve having a portion serially arranged in said channel and adaptable upon actuation for gradually closing said. channel and thereby eilecting a uniform deceleration of the motor to rest, and means in the pilot valve effective after the motor has stopped for connecting said source of fluid pressure to complete movement of the pilot valve and .eilect sequential shifting of the reversing valve to aaemss 1} motor, channel means connecting said source of pressure to each of said portions whereby when said portions are rotated to disconnect the reversing valve both or said motor channels will be connected to said sou rce or pressure, and manually operable means mechanically connected for actuation of said table when said motor channels are interconnected.

3. In a grinding machine having a grinding wheel support and a work support, the combination of transmission means for eflecting relative movement between the supports including a hydraulic motor, a source 01 pressure, a reversing valve having a pair of channels leading to said motor, said reversing valve having an alternately shiitalble plunger for connecting said source of pressure to said channels, a start and stop valve having independent portions serially arranged in said channels and movable to disconnect the reversing valve from said motor, channel means connecting said source of pressure to each oi said portions whereby when said portions are rotated to disconnect the reversing valve both 0! said motor channels will be connected to said source 0! pressure, manually operable means mechanically connected for actuation of said table when said motor channels are interconnected, and fluid operable means adapted to be connected to pressure when said start and stop valve is rotated to connect said channels to said reversing valve for rendering said manually operable means ineflective.

4. In a grinding machine having a grinding wheel support and a work support, the combination of a fluid operable motor tor translating one of said supports, said motor having a pair 01 ports, a hydraulic control circuit for alternately connecting one of said ports to pressure and the means operable when the pilot valve has reached establish hydraulic connections which will reverse the direction of actuation of said motor.

2. In a. grinding machine having a grinding wheel support and a work support, the combination of transmission means for efiecting relative movement between the supports including a hydraulic motor, a source ofpressure, a reversing valve having a pair of connected channels leading to said motor, said reversing valve having a plunger which is alternately positionable for connecting said source of pressure to said channels, a start and stop valve having independent portions serially arranged in said channels and movable to disconnect the reversing valve from said the middle of its stroke for impounding the fluid in both ends of said motor whereby the table would normally stop, and means in the pilot valve for bleeding the fluid from the low pressure side of said motor to insure continued movement oi the pilot valve through its middle position.

5. In a grinding machine of the character described, the combination with a hydraulically reciprocable table, or a hydraulic motor for actua-. tion of the table, a source of hydraulic pressure, a main actuating circuit for connecting said source or pressure with the motor including a control valve having a plurality oi! ports for selectively directing said hydraulic pressure to the motor, an auxiliary circuit, means for selectively coupling said source of pressure to the auxiliary circuit by way of or exclusive or said control valve.

6. A hydraulic control system for a grinding machine or the like including a table actuating motor having a pair or conduits alternatively coupleable with pressure or exhaust, a reversing valve having portings coupled with the respective motor conduits, a pair or potential exhaust conduits extending from said valve, a discharge conduit, 9. rate determinator within said conduit and a control valve intervening said exhaust conduits and said discharge conduit including a plunger member having an intermediate blocking position and extreme positions alternatively effective to couple one or the other of the exhaust conduits with the rate determinator discharge conduit, a pressure connection to said control valve, conduits interconnecting the reverse valve and control valve, and portings in the control valve variably coupling said pressure'connection to said last named conduits for effecting reverse positionings of the reverse valve.

7. A hydraulic control system for a grindin machine or the like including a. table actuating motor having a pair of conduits alternatively coupleable with pressure or exhaust, a reversing valve having portings coupled with the respective motor conduits, a pair of potential exhaust conduits extending from said valve, a discharge conduit, a rate determinator within said conduit, a control valve intervening said conduits including a plunger member having an intermediate blocking position and extreme positions alternatively effective to couple one or the other of the exhaust conduits with the rate determinator discharge conduit, a pressure connection to said control valve, conduits interconnecting the reverse valve and control valve, portings in the control valve variably determining the pressure connection to said interconnecting conduits for effecting reverse shifting of the reverse valve and means intervening the reverse valve and the control valve for variably determining the shifting pressure on said reverse valve in the direction determined by the positioning oi the control valve.

8. In a grinding machine, the combination with a translatable table, of a hydraulic motor for eiiecting translation of the table, conduits coupled with opposite sides of the motor and alternatively employable for introduction or discharge of actuating medium from oppostie sides of the motor, a source of pressure, a reversing valve shiftable alternatively to couple one of said motor conduits with said source of pressure and provide an exhaust connection for the other of said conduits, bleeder discharge conduits coupled in parallel with the motor conduits, and a control valve serially interposed in the exhaust connection from the reversing valve and the bleeder discharge conduits from the motor, said control valve having a first portion positionable to block flow in said exhaust connection, from the reversing valve and a second portion simultaneously positionable to partially block discharge through the bleeder conduits.

9. A hydraulic control system for controlling reversible operationoi' a hydraulic motor connected for reciprocating a movable member including a source of pressure, a reverse valve for reversing pressure and exhaust connections to the motor for determining the direction of movement oi the member, a control valve in said connections shiitable from one extreme position to another and through a center position, means on the valve when in a center position for blocking the flow from said motor, other means on the valve when in a center position for bleeding the low pressure side of the motor to maintain movement of the motor while the flow therefrom is blocked, and additional means on the control valve responsive to the admission oi hydraulic pressure thereto as the valve passes its center position to complete the shifting movement of the control valve to its other extreme position whereby said connections will be unblocked, and means in the control valve for coupling pressure to shift the reverse valve.

10. A hydraulic control system for a movable member of a. machine including an actuating motor having a pair of conduits alternatively coupleable with pressure or exhaust, a reversing valve having portings coupled with the respective motor conduits, a pair of potential exhaust conduits extending from said valve, a discharge conduit, a rate determinator within said discharge conduit, a control valve intervening said pair of conduits including a plunger member having an intermediate blocking position and extreme positions on opposite sides thereof for alternatively eflecting coupling 01' one or the other of the exhaust conduits to the rate determinator discharge conduit, 9. pressure connection to said control valve, conduits interconnecting the reversing valve and control valve, portings in the control valve variably determining the pressure connection to said interconnecting conduits for eflecting reverse shifting of the reversing valve, means intervening the reversing valve and the control valve for variably determining the shifting pressure on said reversing valve in the direction determined by the control valve, and independently operable valve means in said hydraulic system-i'or starting and stopping the motor.

' JACOB DECKER.

HANS ERNST.

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