US2379180A

US2379180A - Hydraulic retractor control

Info

Publication number: US2379180A
Application number: US318255A
Authority: US
Inventors: Walter M Pohl
Original assignee: Vickers Inc
Current assignee: Vickers Inc
Priority date: 1940-02-10
Filing date: 1940-02-10
Publication date: 1945-06-26
Anticipated expiration: 1962-06-26

Description

June 26, 1945. IW M FCHL A 2,379,180

HYDRAULI C RETRCTOR CONTROL Filed Feb. lO, 1940 2 Sheets-Sheet l INVENTQR. afffef M ,F/72

June 26, 1945. w.- M PoHL HYDRAULIC RETRAGTOR CONTROL Filed Feb. l0, 1940 2 Sheets-511861'I 2 Q5 Nw. www

WN EN WM Y cylinder I and a piston II.

Patented June 26, 1945 HYDRAULIC RETRACTOR CONTROL Walter M. Pohl, Washington, D. C., assigner to Vickers, Incorporated, Detroit, Mich., a corporation of Michigan Application February 1o, 1940, serial No. 318,255 'A (c1. so-52) is claims.

This invention relates to a hydraulic retractor control and has particularly to do with an improved control system for a hydraulic motor.

An object of the present invention is t0 prvvide a hydraulic control system in which a novel arrangement oi' valves permits the continued movement of a motor to be effected'by slight movement of the motor by an external force in the particular direction concerned.

'A further object of the invention is the provision of a system which may operate automatically but may be fully controlled by manual op.. eration. The hydraulic control system concerned herewith is especially adapted tothe rammer mechanism of large guns in which it is desirable to have the retraction movement initiated by g'un recoil. I t is also adapted to a wide variety of commercial apparatus such as conveying machinery and the closing and opening of doors on industrial furnaces.

Other objects and features of ,the invention relating to the details of the hydraulic circuit and the operation thereof will be brought out in the following description and claims.

In the drawings: l

Fig. 1 is a circuit diagram mostly in section with each of the conduits being shown in a single plane for purposes of illustration.

Figs. 2 and 3 are views of portions of Fig. 1

showing the parts in diierent relative positions though a portion of Fig. 2 is modied from Fig. 1. An illustration of .the principles of therinvention will now be described in connection with the drawings. A motor to be driven, consists of a A rod I2 extends from the motor through one end of the cylinder. A motor I3 drives a pump I4 which serves as a main pressure source and a pump I5 serves as a source ofipilot pressure. A valve block is shown Vat I5 and in this valve block are located a directional control valve I'I for controlling pressure from the main source.Y A directional control valve i8 controls pressure from the pilot source and an additional control valve I9 controls, simultaneously, pressure from said each end thereof and these ports are connected respectively to conduits 24 and 25 leading from the valve I `It will be seen that the ports 22 and 423 do not enter the cylinder at the extreme ends tliereof. Additional passageways 26 and 21 lead to a point directly adjacent the ends of the cylinder and these passageways are each closed by a check valve 23.

The valve I'I consists of a spool which is located in a cylindrical recess inthe housing -I6, said spool having two

end piston formations

29 and 30 and two central pistons 3| and 32. The lower end of the valve I1 extends into a chamber 33 and is surrounded by a spring 34 whichbears against

washers

35 and 33. Movement of these washers on the valve is limited in one direction respectively by the piston formation 29 on the one end and a collar 31 at the lower end. The washers have a loose fit on the valve so that pressure may pass around them. as in the Acase of l washer 38, to the chamber directly below the valve. Whenthe valve is in neutral position, as shown in Fig. l, each of these washers bears on a shoulder in the valve housing and it will thus be seen that the spring 34 tends to maintain the valve I1 in its neutral position. Above the piston formation 30 is formed a chamber 33 and an auxiliary chamber 39 is provided above the chamber 38, a piston member 40 extending from the chamber 39 through the chamber 33 to contact the valve. A conduit 4I connects the chamber 33 with the valve recess o1' valve I3 and similar1y, a conduit 42 connects chamber 3B with valve I3.

The chamber 33 is connected to a valve recess I9a of the valve I 9 by a conduit 43 and this valve recess I9a is also-connected to -an extension 2Ia of conduit 2l leading from the pilot pump. A tank conduit 44 connects the valve recess of valve II to the tank and a, conduit 45 connects valve recess I 9a and valve I8 to the tank.

The valve Iiiv is provided with

tank passages

45 and 41, which each connect with the conduit 45. 'Ihe ends of this valve are vented to this line. A spring 43 acts on the valve I3 so that movement of the valve must be against this spring.

Referring now to the connection between -the valve I8 and the motor III-I I, the piston rod I2 which moves in and out o'f the cylinder I0 is provided with a contact member which is adapted to cooperate with. a cam lever 5I mounted on a rod 52. At the other end of the rod 52 is a latch 53 which connects to a rod 54 at the lower end' of the valve I3. A spring pressed bell crank 55 pivoted at 53 is provided with a knob 51 which 'f is hunted bya relief valve 50 and the pressure in.

conduit 2| is limited by an actuator relief valve 6I which consists of a spring backed piston 62 which bypasses the line 2l to a tank conduit 63 when a certain amount of pilot pressure has ac'- cumulated in a chamber 84.

A check valve is shown at 61 normally held in closed position by a spring 68. Conduit 69 leads from valve recess of valve I1 to valve 61. The other side of valve 61 is connected with tank conduit 44.

In the operation `oi? the device, assuming that the -piston II was in its extreme right position in cylinder I 0, a movement of lever 59 to the forward position indicated will shift the latch 53 downward so that it will be caught beneath the knob 51 on bell crank 55 as shown in Fig. 3. Valve I8 will then be shifted to the position shown in Fig. 3 and pilot pressure may pass from conduit 2I to conduit 4I and chamber 33. This will cause an upward shifting of valve I1 and by reason of this shifting, conduit 20 from the main pressure source will be connected to conduit 25 leading to the right end of cylinder II) (Fig. 3). At the same time conduit 24 will be connected to tank conduit 44 and piston II will start moving in a direction shown by the arrow in Fig. 3.

As the piston II reaches its extreme left position, as shown in Fig. l, the contact member 5,0 will move cam 5| and valve I8 to the position shown in Fig. 1. This movement of the valve I8 will block pilot pressure from conduit 4I and connect both conduits 4I and 42 to the

tank conduits

45, 46 and 41. Spring 34 maythen return the valve I'I to its neutral position as shown in Fig. 1. In this position, it will be seen that pressure from the main conduit 20 maypass around valve I1 to tank conduit 44 and the pump I4 will thus be unloaded. At this time the conduit 24 is also connected to the tank conduit 44 and the conduit 25, leading from the motor, is connected to a short conduit 65 which leads to the piston end of valve I9. A spring 66 normally maintains the piston valve I9 in the position shown so that the conduit 65 is closed from conduit 20 which passes around the valve I9.

With the parts as shown in Fig. l, it will be seen that a slight movement of the piston II to the right by an external force will direct liquid from cylinder I0 through the conduit 25 to the conduit 65.

Since there is no other outlet for this liquid the piston valve I! will be shifted to the right thus opening conduit 20 to conduit 25. At the same time the pilot extension conduit 2 Ia is connected through a recess in piston valve I9 to conduit 43 which leads to the auxiliary chamber 39 above piston I1. Pilot pressure will thus be exerted on the piston member 40 and the valve I1 will be shifted to the position shown in Fig. 2. In this position conduit 24 is blocked from the tank and connected to conduit 20 so that both of the motor ports are connected to the main pressure source. Because of the differential areas on the respective sides of the piston II, there will be a continued movement of the piston to thc right, as shown by the arrow. Consequently, it will be seen thatran automatic retracting movement is eiected by a slight movement in the same direction exterted on the piston rod I2. In the case of the application of the system to the rammel' of a gun, the recoil movement of the gun may be used to effect the slight initiating movement and the hydraulic system will effect the continuation of the movement.

Check valve B1 operates only during the initial movement of the retraction cycle (Fig. 2) to admit uid from the tank to conduit 24 for filling the void created by the initial movement of piston II before valve I1 has been shifted in the manner just explained. It will be seen also that in case it is so desired, the retraction movement may be initiated by shifting the hand lever 59 to the retraction position thereby shifting valve I8 to the position shown in Fig. 2 and connecting conduit 2| with conduit 42 and chanber 38. Also, if immediate retraction is desired the contact member 50 may-be lengthened, as shown in Fig. 2, at 50a so that the cam lever 5I will be shifted, not to its neutral position, shown in Fig. 1, but to the retraction position, as shown in Fig. 2.

What I claim is:

1. In a hydraulic system, a pressure source, a reversible motor means to be actuated by pressure from said source, means for directing pressure to said motor means to cause actuation in one direction, and means responsive to slight movement of said motor in the other direction to eiect continued operation in said other direction of said motor by pressure from 'said source.

2. In a hydraulic system, a pressure source, a reversible motor means to be actuated by pressure from said source, a pilot operated directional control valve for directing pressure from said source to said motor to control the movement thereof, a source of pilot pressure, means for directing said pilot pressure to said pilot oper- -ated' valve to shift the same to cause actuation of said motor in one direction, and additional means responsive to slight movement of said motor in the other direction to direct pilot pressure to said pilot operated valve to cause continued movement of said motor in said ,other direction.

3. In a hydraulic system, a pressure source, a reversible motor means to be actuated' by said source comprising a piston-cylinder motor, said piston having a greater working area on one side than on the other, means for directing pressure from said source to one side of said piston to effect movement in one direction, and means responsive to slight movement of said piston in the other direction to effect continued operation in said other direction of said piston by effecting the connection of both sides thereof to pressure from said source.

4. In a hydraulic system, a main pressure source, a reversible motor means to be actuated by pressure from said source and having motor ports, a pilot operated directional control valve for directing pressure from said source having a neutral position in which pressure from said source is bypassed and working positions in which pressure is directed to respective ports of said motor to actuate said motor in opposite directions, a pilot pressure chamber at each end of said control valve, a source of pilot pressure, a pilot valve arranged to be shifted to direct pilot pressure to one or the other of said chambers to shift said control valve, means for shifting said pilot valve, and additional valve means shiftable in response to movement of saidv motor in one direction to effect connection through said control valve of both of said motor ports t0 said main pressure source.

5. In a hydraulic system, a main pressure source, a reversible motor means to be actuated by pressure from said source and having motor ports, a pilot operated directional control valve for directing pressure from said source having a neutral position in which pressure from said source is bypassed and working positions in which pressure is directed to respectiveI ports of said motor to actuate said motory in-opposite directions, a pilot pressure chamber at each end of said control valve, a source `of pilot pressure, a pilot valve arranged to be shifted to direct pilot pressure to 6. In a hydraulic system, a main pressure source, a reversible motor means to be actuated by pressure from said source and having motor ports, a pilot operated directional control valve for directing 'pressure from said source having a neutral position in which pressure from said source is bypassedl and working positions in which pressure is directed to respective ports of said motor to actuate said motor in opposite directions. a pilot pressure chamber at each end of said control valve, a source of pilot pressure, a pilot valve arranged to be shifted to direct pilot pressure to said motor, pressure chambers at each end of l said valve for receiving pilot pressure to cause shifting of said valve, an auxiliary chamber at one end of said valve, means in said auxiliary chamber responsive to pilot pressuretherein to cause shifting of said valve, pilotI control valve means arranged to direct pressure from said pilot source to one of said pressure chambers to shift said main valve to a working position to cause movement of said motor in one direction, and additional valve means for directing pressure from said pilot source to said auxiliary chamber to cause shifting of said Vmain valve, said additional valve .means being responsive to slight movement of said motor in the other direction to eifect shifting of said main valve to cause a continued movement of said motor in said other direction. Y

9. In a hydraulic system, a main pressure source, a source of pilot pressure, a reversible motor to be shifted by pressure from said main source, a main valve for controlling pressure from said source arranged to be shifted from a neutral one or the other of said chambers to shift said control valve, means for shifting said pilot valve, and additional valve means arranged to cooperate with said control valve and sliiftable in response to slight movement 'of said motor in `one direction to direct pilot pressure toshift said confor directing pressure from said source having a neutral position in which pressure from said source isobypassed and working positions in which pressure is directed to respective ports of said motor to actuate said motor in opposite directions, a pilot pressure chamber at each end of Y said control valve, a source of pilot pressure, a pilot valve arranged to be shifted to direct pilot 'pressure to one or the`other of said chambersto shift said control valve, means for shifting said pilot valve to cause .setting of said control valve to effect movement of said motor in one direction,` means operably connected to said pilot valve arranged to shift said pilot valve to neutral position upon 'predetermined movement of said motor in said one direction, and ladditional valve means arranged to cooperate with said control valve and shiftable, when said control valve is in neutral position, inresponse to slight movement of -said motor in the other direction to direct pilotI pressure to shift said control valve to a working position wherebypressure from said main source will be directed to ,said motor to eect continued operation' in said other direction.

8. In a hydraulic system, a main pressure source, a source of pilot pressure, a reversible motor to be shifted by pressure from said main source, a main valve .for controlling pressure from said source arranged to be shifted from a neutral position-b said mainsource, to working positions in which pressure is directed to position bypassing saidV main source, to working positions in which pressure isdirected to said motor, pressure chambers at each `end of said valve for receiving pilot pressure to cause shifting of said valve, an auxiliary chamber at one end of said valve, means in said auxiliary chamber responsive to pilot pressure therein to cause shifting of said valve, pilot control valve means arranged to direct pressure from said pilot source to one of said pressure chambers to shift said main valve to a worng position to cause movement of said motor in one direction, and additionalV valve means for directing pressure from said pilot source to said auxiliary chamber to cause shifting of said main valve, said additional valve means being responsive to slight movement of said motor inthe other direction, when said main valve is in neutrall position,.toeil'ect transfer of pilot pressure to said auxiliary chamber whereby said main valve is shifted to a working position to cause continued movement of said motor in said other direction.

, 10. In a hydraulic system, a main pressure source, a soin-ce of pilot pressure, a reversible motor to be shifted by pressure from said main source, a main valve for controlling pressure from said source arranged to be shifted from a -neutral position b said main source, to working positions in which pressure is directed to said motor, a means for biasing said valve to its neutrai position, pressure chambersat each end of said valve for. receiving pilot pressure to cause shifting of said valve, an auxiliary `chamber at one end of said valve, means in said auxiliary chamber to pilot pressure therein to' cause shifting of said valve, pilot control valve meansarrangedtodirectpressurefromsaidpilot .Y

source to one of said pressure chambers to shift sammain valve to' a working position m cause movement of said motor in one direction, and

'additional valve means for. pressure from said pilot source to said auxiliary chamber to cause shifting of said main valve, said additional valve means being e to slight movement of said motor in the other direction to effect shifting of said m'ain valve tocause a continued movement of said motor in said 'other direction.

rl1. In va hydraulic system, amain pressure source, asource of pilot pressure, a reversible motor to be shifted bypressure from said main source,a main valve for controlling pressure from sure from sai said source arranged to be shifted from a neutral position bypassing said main source, to working positions in which pressure is directed to said motor, pressure chambers at each endl of said valve for receiving pilot pressure to cause shifting of said valve, an auxiliary chamber at one end of said valve, means in said auxiliary chamber responsive to pilotpressure therein to cause shifting of said valve, pilot control valve means arranged to direct pressure from said pilot source to one of said pressure chambers to shift said main valve to a Working position to cause movement of said motor in one direction, means, for causing automatic shifting of said main valve to neutral position in response to a predetermined movement of said motor, and additional valve means for directing pressure from said pilot source to said auxiliary chamber to cause shifting of said main valve, said additional valve means being responsive to slight movement of said motor in the other direction, when said main valve is in neutral position, to eiect transfer of pilot pressure to said auxiliary chamber whereby said main valve is shifted to a working position to 'cause continued movement of said motor in said other direction.

12. In a hydraulic system, a pressure source, a reversible motor means to be actuated by pressource, motor ports on said motor and conduit means for connecting said ports to said pressure source, valve means in said conduit means shiftable to control the iiow of pressure from said source to said ports and thereby control the direction and movement of said motor, a source of pilot pressure, and pilot control means adapted to control the inuence of pilot pressure on said first named valve means, said pilot control means comprising a manually operated valve and an auxiliary control valve adapted to be pressure operated, said manually operated valve being adapted to control the ow of pilot pressure to and consequent shifting of said first named valve means in either direction, said auxiliary valve means being responsive to slight movement oi said motor in one direction to direct pressure to said rst named valve means to shift the same and cause continued operation of said 4motor in said direction by pressure from said source.

13. In a hydraulic system, a pressure source, a motor means comprising relatively movable parts to be actuated by pressure from said source, valve means shiftable to operatingpositions for directing pressure to said motor means to cause actuation thereof, and means hydraulically shiftable in response to pressure built up by relative movement of said motor parts by an external force and cooperating to cause shifting of said yvalve means to an operating position to effect continued relative movement of said partsby pressure from said source in the same direction as that initiated by the external force.

WALTER M. POHL.