US2263421A - Valve device - Google Patents

Description

Nov. 18, 1941- F. F. HARRINGTON VALVE DEVICE Filed Feb. 29, 1940 INVENTOR FERR l S T. HARRINGTON ATTORNEY and so. constructed as to maintain a predeter- Patented Nov. 18, 1941 7 'pN TED STATES PATENT OFFICE VALVE DEVICE Ferris T. Harrington, Detroit, Mich, assignor to Vickers Incorporated, Detroit, Mich, a corporation of Michigan Application February 29, 1940 Serial No. 321,426

4- Claims. (61. 121-465) This I invention relates to power transmis- 24 of a combined four-way and foot valve gensions, particularly to those of the type compriserally designated 26. The latter has a tank coning two or more fluid pressure energy translating nection 28 which communicates with the tank I4 devices, one of which may function as a pump through a conduit 30. The valve 24 is provided and another as a fluid motor. with two motor connections 32 and 34 (shown in This invention is more particularly concerned dotted lines in Figure 1) and which are conwith a combined four-way directional valve and foot valve for use with a fluid motor for operating a machine tool slide or other driven device. Certain types of motors and load devices have been heretofore provided with,a foot valve, so called, arranged in the return line from the motor of a fluid motor 48. The latter comprises a cylinder in which a piston 42 is slidable, the rod 44 of which carries a suitable head or other work device generally designated as 46.

' The valve 24 is provided with a pair of projecting stems 48 and 58 adapted to be operated by mined back pressure on the fluid exhausting from solenoids 52 and 54 through the medium of levers the motor. Where the foot valve is between the 58 and 58. For the purpose of controlling the four-way valve and the motor a--check valve is energization of solenoids 52 and 54 an electric nected by conduits 36 and 38 to the opposite ends necessary to permit free return flow to the motor in the opposite direction. Where the foot valve is between the four-way valve and the tank the back pressure is imposed during both directions of movement although it is only necessary in one direction.

An object of the present invention is to pro-,- vide a'com'bined directional control valve and foot valve in a unitary body.

A further object is to provide in a valve of this character improved circuit arrangements permitting free flow around the foot valve without check valves under all operating conditions when the foot valve is not required. 4

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawingwherein a preferred form of the present invention is clearly shown.

In the drawing: I

Figure 1 is a longitudinal cross section of a valve embodying-a. preferred form of the present invention.

Figure 2 is a diagrammatic view of a power transmission system embodying a preferred form n of the present invention.

Figure 3 is a detailed cross sectional view on the line 33 ofFigure 1. 7

Referring now to Figure 2, there is shown a pump i0 adapted to be driven by a, suitable prim mover, such as an electric motor E2. The pump I0 withdraws fluid from a tank I4 through a suction conduit I6 and delivers it to a delivery conduit I8. The latter has a relief valve 28 of conventional construction for bypassing oil to the tank through a conduit 22 whenever a predeterminedpressure is exceeded in the delivery conduit ill.

The conduit i8 extends to the pressure port 55 30 switch 12.

0 gize circuit'is provided as follows: A momentary contact starting switch 68 when closed connects between a line L running from one side of a suitable source and a conductor 62. The latter ex- 54 the other side of which is connected to the other side of the line LP. The holding circuit for the relay 64 extends from the coil thereof by a conductor 68 through the holding contacts of the relay and by a conductor 10 to the normally closed contacts of a double-throw limit The latter is adapted to be actuated by a cam I4 on the head 46 when the latter reaches the lower limit of its stroke.

The normally open contacts of the limit switch l2 connect between line L and a conductor 15 winch leads to the operating coil of a second holding relay 16. The relay 18 when energized closes a circuit between line L and a conductor 18 extending to solenoid 52, the other side of which is connected to line L. The holding circuit of relay "extends from the coil thereof by a conductor through the holding contacts and by a conductor 82 to a normally-closed limit switch 84 and line L The latter is adapted to be opened by the cam 14 when the head 46 is in 45 its fully raised position, as illustrated. Each of the solenoids 52 and 54 is preferably provided with internal return springs, not shown, whereby the spool of valve 26 is maintained in a c tral position when neither solenoid is ener- Re erring now to Figure '1, the valve 26 compriseg a body 88 having a bore 90 within which is.

s 1y mounted the spool 92 whichcarries the stems 48 and 50. The latter are provided with slots 96 within which the lower ends of the levers nular ports arranged I60 communicating between 2 56 and 58 extend. Suitable abutment screws 98 are provided for adjusting the position to which the solenoid will shift the spool 92. Springpressed plungers I are mounted in bores I02 in th spool 92 and serve to maintain the levers 56 and 58 in close contact with the abutment screws.

The bore 90 is provided with a plurality of analong its length as shown in Figure 1. Thus-the annular port I04 constitutes the pressure port of the valve and is connected by a passage, not shown, in the body with the pressure connection 24 of Figure 2. On either side of the pressure port I04 are motor ports I06 and I08 which communicate with the motor connections 32 and 34. At the outside of the motor ports there are provided tank ports H0 and H2, as shown.

The spool 92 is provided with three lands I22,

I24 and I26 which in the neutral position of the valve lie opposite the ports II2, I04 and H0 respectively. The spool 92 is also provided with a central bore'I28 which connects between radial cross bores I30 and I32. The latterin the neutral position of the valve open into the ports I04 and III! respectively.

In the lower part of a second valve bore II6 of the foot valve is mounted. The bore H4 is provided with two annular grooves H8 and I20 which form inlet and outlet ports respectively for the foot valve. The spool H6 is provided with a land I34 which normally closes the port I20 from communication with the port H8 in the left hand position of the spool I I6 shown. When the spool is shifted to the right by means later to be described, communication is opened from port II8 to port I20.

Mounted on the body 88 at the left hand end of bore H4 is an end cap I36 within which is formed a small cylinder I38. The latter carries a small floating piston I 40 adapted to abut against a projection I42 formed on the left hand end the body as there is formed of the spool H6. The left hand end of cylinder I38 communicates by a passage I44 with the'port- I I8 so that whatever pressure exists in the latter will be exerted on the left hand face of the piston I40.

At the right hand end of bore II4 an end cap H4 within which the spool livered through the connection nection 28 to the tank conduit 30. The pump is thus maintained unloaded during all times that the spool 92 is in neutral position;

When it is desired to advance the head 46 downwardly the starting switch 60 is closed thus energizing the relay 64. The latter picks up closing its holding circuit through the normally closed contacts of switch 12. The relay 64 also energizes the solenoid 54 thus rocking the lever 58 clockwise to shift the spool 92 to the left. The

pump delivery is accordingly directed from pressure po'rt I04 to motor port I06 where it is de- 32 and conduit 36, to the head end of the motor 40. Oil pushed out of the lower end of motor 40 returns through the conduit 38, connection 34, port I08, tank port H2 and passage I62 to the inlet chamber IIB of the foot valve. I

In order for the oil to pass out of chamber II8 the valve spool II6 must shift to the right. This is accomplished by the pressure building up in chamber I I8 and being transmitted through passage I44 to the small cylinder I38 where it pushes the piston I40 and spool II6 to the right against the force of spring I50. The degree of pressure required to thus open the foot valve depends upon the adjustment of spring I50, and this adjustment is normally sufficiently high so as to prevent the gravity load of the head 46 from pulling the piston 42downwardly.

As the piston 42 and head 46 complete their downward stroke the cam I4 rides onto the limit switch I2 thus opening the holding circuit for relay 64 and' at thesame time energizing the relay I6. The latter picks up, closing its own is now closed. The relay spool 92 to its I46 is mounted. The latter carries an adjusting screw I48 for the purpose of adjustably determining the force of a spring I50 which is mount-' ed within the hollow portion of the screw I48 and abuts against the right hand end of the spool II6. Suitable locking. and acorn nuts I52 and I54 are provided on the projecting end of the screw I48. A replaceable stop washer I56 is mounted between the body 88 and the face of the end cap I46 to serve both as an abutment for the spool H6 and for the screw I48 to limit the maximum travel of both elements. A seepage drain passage I58 is formed in the end cap I46 and communicates with the port I20.

The body 88 is provided with a cored passage the tank port H0 and the tank connection 28 and passing across the annular port I20 at the bore II4. Also the body is formed with a second passage I62 connecting between the tank port H2 and the inlet port H8 at the bore M.

In operation, assuming the pump I0 to be driven by the motor I2, oil is withdrawn from the tank I4 through suction conduit I6 and delivered through the conduit I8 to port 24 of the valve 26. With the spool 92 in the neutral position illustrated the full pump delivery is bydition of the pump 16 also energizes the solenoid 52 through the circuit I8 thus shifting the lever 56 counterclockwise which carries the right hand position. Oil from the pump delivery line is now directed from port I04 to port I08 where it leaves through connection 34 and conduit 38 to enter the lower end of motor 40. The piston 42 and head 46 accordingly retract upwardly discharging oil through the conduit 36, connection 32, ports I06 and H0, and passage I60 to the tank conduit 30. It will be noted that during the return stroke the discharging oil from the motor is free to pass to the tank without the back pressure being imposed by the foot valve. This is accomplished without the use of a check valve.

When the piston 42 reaches the upper limit of its stroke the cam I4 again contacts the limit switch 86 opening the latter to deenergize the solenoid 16. The spool 92 accordingly returns to center position under the influence of the springcentering means associated with the solenoids 52 and 54, and the pump is again unloaded as described at the start of this operation.

Itwill be noted that during the unloaded conthe pump delivery passes free- 1y to tank through the passage I60 and is unrestricted by the foot valve.

While the form of embodiment of the invention asherein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What'is claimed is as follows:

1. A combined. four-way and foot valve for controlling the flow -of fluid to and from a hydraulic motor comprising a body having a. pluforming a pressure port, a pair oi motor ports and a pair of tank ports atfthe flrst bore, said spool being shii'table to selectively connect the pressure port with either motor port and simultaneously connect the other motor port with one or the other of the tank ports, means forming a tank connection to said body, an unobstructed passage between said connection andone oi the tank ports. said passage communicating with the outlet of the foot valve, and a passage connecting the other tank port with the inlet of the foot valve.

2. A combined four-way and foot valve for controlling the flow of fluid to and from a hydraulic motor comprising a body having aplurality of valve bores, a four-way valve spool slidably mounted in one bore, a pressure responsive i'oot valve mounted in the other bore, means'i'orming a pressure port, a pair of motor ports and a pair'ot tank ports at the first bone, said spool being shiitable to selectively connect the pressure port with either motor port and simultaneously connect the other motor port with one or the other 01' the tank ports, said four-way valve further having a neutral position in which the pressure port is cut oil from both motor ports. means forming a tank connection to said body, an unobstructed passage between said connection and one of the tank ports, said passage com-- municating with the outlet or the foot valve, and

' a passage connecting the other tank port with the inlet-oi the foot valve, said tour-way valve having an unloading passage eflecti've in neutral position to connect the pressure port with that tank port which communicates freely with the tank connection.

3. A directional control valve for a fluid motor comprising a bodyand shii'table valve member iorminga reversing valve with a pressure port, motor ports and a. plurality of tank ports ary ranged for selective connection of the pressure port with either motor port and the simultaneous connection of another motor port with one or another oi. the tank ports, means forming an open tank passage from one tank port, means forming a second passage from another tank port,'and a pressure-responsive foot valve in the second passage and arranged to block the second passage at pressures below a predetermined value and to connect the second passage to tank at higher pressures.

4. A directional control valve for a fluid motor comprising a body and shiitable valve member forming a reversing valve with a pressure port, motor portsand a plurality of tank ports arranged ior selective connection 01' the pressure port with either motor port and the simultaneous connection of another motor port with one or another oi the tank ports, means forming an open tank passage from one tank port, means forming a second passage from another tank port, a pressure-responsive toot valve in the second passage and arranged to block the second passage at pressures below a predetermined value and to connect the second passage to tank at higher pressures, and means for bypassing the pressure port to said one tank port when the directional control valve. is in neutral position.

' FERRIS T. HARRINGTON;

Images