US2304131A - Pump jack circuit - Google Patents

Description

D@n 8,1941Y t HQFMCkERs 2,304,131

C PUMP JACK CIRCUIT Filed Feb; 18, 1938 2 SheetsSheet 1 {E9-Z l j I A vINVENTOR.

HHRRYE l//c/nf-"u- ATTORNEY.

. 8i 1942.' H. F. vlcKERs PUMP/ACK CIRCUIT Filed Feb. 1s', 193s' 2 Sheets-Sheet 2 INVENTOR. #www F Mcmsks Patented Dec. 8, 1942 l UNITED STATES 1?.-21115N'ry oFFlcl:

2,304,131 PUMP JACK CIRCUIT Harry F. Vickers, Detroit, lMich., assignor to Vickers, Incorporated, Detroit, Mich., a corporation of Michigan Application February 18, 1938, Serial No. 191,189 4 claims. v(01121-1513) Ycontrol units are so arranged that they are mechanically independent of the main jack cylinder and may control it from a remote position.

Other features of the invention have to do with the combination of the hydraulic control with ac- K curate adjustable flow control and time delay devices and with other details of construction as will be brought out in the following description and claims.

Certain constructions in accordance with the invention are illustrated by way of example, in the accompanying drawings, in which:

Fig. 1 is a cross section of a time lag device to 25 be used in the control circuit, all the passageways being shown in the same plane for purposes of illustration. Y

Fig. 2 is a diagrammatic presentation of the circuit of one modication of the invention utilizing a piston-cylinder time Acontrol.

Fig. 3 illustrates a modied diagrammatic circuit wherein the time lag device of Fig. 1 is used. Figsqi and 5 illustrate sectional views-of the four-way valves of Fig. 2.

Referring to Fig. 2, the main elements of the circuit consist of a constant delivery pump 5,v a hydraulicram or jack S and a piston "I, la tim-4 ing cylinder 8, and a, series of valves intercon- I 35 ger 28 arein another.

relief valve i9 is equipped with a spring which maintains a low back pressure suilicient to operate the pilot control system and this valve also prevents the load from falling in case of power fail- ,5 ure during hoisting. The four-way valve i2,

which is shifted by pilot pressure, controls the direction of'movement of the main cylinder and directs the pump delivery either to the cylinder 9 or to the tank. During the lowering of the ram,

10 liquid from'lthe cylinder 5 is directed to the tank through the globe Aor throttle valve II. The ram piston 'I is lowered by gravity and the rate of the lowering is adjusted by the globe valve I I, the upper rateof the ram'being constant under the delivery of pump 9.

An auxiliary control for .determining the length of the stroke of the ram l is provided by the timing cylinder 8, pilot operated four-Way valve I 3, pilot valve I9, and the ow control valve I5.

2g Branching oil from a conduit Il between two valves 9 and I0 is a pilot pressure conduit I9.

which leads to the four-way valve i3. This valve is adapted to direct pilot pressure to either end of the cylinder 9 ,depending on the position in which the valve is shifted. Conduits I 9 and 29 lead to the timing -cylinder 8 while conduits 2l and 22 connect the conduits I 9 and 20 respectively with opposite ends of the pilot operated valve i2. A piston 23 within the timing cylinder 8 is provided with piston rods 26 and 25, the latter beingprovided. with adjustable dogs 26and 2l which operate the pilot v alve It by engaging` ngers 28 and 29 ofthe pilot valve. Dog 26 and nger 29 are in one plane while dog 2l and iin- A conduit 30 directs pressure from :the pilot pressurev conduit I8 to the pilot valve I8 and conduits 3| and 32 lead from the pilot valve I5 to the respective ends of the four-way valve i3. A conduit 33 connects the nected by hydraulic conduits. The valves in the 40 valve I3 with the iiow control valve- I5 which m system consist of a relief Vvalve 9, a check valve I0 which serves as a low pressure relief valve, a

globe or throttle valve l I, two pilot operated fourway valves I2 and I3, a pilot valve it, anda ilow Vcontrol valve I5. This ow control valve is of the v45 type disclosed in British Patent No. 399,609J of June l1, 1932.

'the various elements of the system and lead 'to 'turn' is connected to the tank through conduit 33.

The cycle of operation 'of the circuit of Fig. 2 is as follows: Assuming that the dog 2'6 has just shifted the linger 29 of the pilot valve It clockwise, pilot pressure is directed from the pump 5 through conduits Il, i8, 30 and 3| to the lefthand side of the four-way Vvalve I3. This valve is shifted by this pilotv pressure (see Fig. 4) so that .the righthand Side,of fthe-timing cylinder '8 is and from a tank I6 willbe described in connec- 50 connected to the conduit I8 and the lower'side tion with the detail description of the circuit.

Pressure for raising' the ram 1 is supplied by the Y pump 5 to the cylinder 6 through the relief valve V9, the low pressure relief valve Ill, andthe pilot` of the four-way valve I2 lis also open to the pilot pressure through conduit 22. By reason of this pressurev in conduit 22, the valve I2 is shifted (see Fig. 5) so that the vmain cylinder 6 is open to the operated four-way valve |2.' The low pressure 55 tank through the throttle valve I I. The pump pressure caused bythe valve I3 and passes through the valve I2 to a conduit 35. .While the timing piston 33 is being moved to the left by the pilot pressure, the main ram 1 lowers by gravity.

When the dog 21 shuts the levers or the puot 2,304,131 delivery is returned to the `tank at the low back` respectively. Ports 59 and 59a of the timing valves are connected by suitable conduits to the tank I5. An outlet conduit 80 fro'm the valve 4I)v iS also connected to the tank through the adjustvalve I4 counterclockw'ise, pilot pressure is directed to the righthand side of the four-way valve I3, shifting the same so that the pilot pressure from the conduit I8 is directed to the left-f hand side of the timing cylinder`8 through the conduit I9 and to the upper side of. the four-way valve I2 through the conduit 2l. This latter valve is shifted so that the delivery of the pump is directed to the main cylinder- 5 so that the pump pressure is built up to raise the ram 1. While the timing piston 23 moves to the right the ram 'I is elevated by the pump pressure. When the piston 23 reaches the end of its stroke, to the right, the pilot valve I4 will again be shifted in the clockwise direction so that the four-way valve I2' will'be reversed and a cycle will start to repeat.

It will be seen that in this circuit of Fig.' 2 the piston 1 in the main.` cylinder reverses at the same time that the timing piston 23 reverses,

so that by adjusting the stroke time of the timing'cylinder 8, the length of the stroke of the piston in the -main cylinder 8 may be accurately controlled. The adjusting of the ,stroke time of the timing cylinder 8 is accomplished by reason of the fact that when the pilot pressure is being directed from the conduit I8 to one end of the timing cylinder I8, the other end of the cylinder will be connected through the four-way valve I3 r and the conduit 33 to the adjustable flo'w control valve I5. With this arrangement the stroke time of the piston 23 can be accurately determined. The length of the stroke of the main cylinder is consequently controlled by thepow control valve I5 since pressure fluid is supplied to the main cylinder at a constant rate. The stroke time of the timing cylinder 8 may also be varied by adjusting ngers 26 and 21:closer together or far ther apart.

The modification shown in Fig. 3 is adapted able throttle valve 38.

A cross section of the timing valve 4| is shown -in Fig. 1. This valve isknown as a time delay valve and consists essentially of a hydrostatic or constant flow valve 8|, a xed throttle 62 and a f ree piston 63, `The hydrostatic valve is of the same type as described in my Patent No. 1,982.711, dated December 4, 1934. Assuming the valve to b e in set position as shown in Fig. 1,

the operation is as follows: Oil under pressure is admitted at 'port 56 and metered through the l hydrostatic flow control valve 6I and the fixed throttle 62 to a chamber 84 behind the piston 33. The piston moves slowly to-the left until a rport ss is open to the champer sa at 'which time `The' piston 53 is thenmoved tothe right until it contacts an adjusting screw 61. A- check valve 68 allows displacement of liquid from the chamber 84 during the reset stroke of the piston. A check valve '59 allows displacement. f pressure fluid from the actuated unit through the Vport 41 during the reset stroke.

In ylthe operation: Referring to `the circuit of Fig. 3, it will be seen that pressure to or from the cylinder 5 must pass through the ,pilot operto perform the same functions as that shown in` Fig.- 2 but the circuit for accomplishing these results is considerably different. Referring to Fig. 3, the main elements of the system consist of the pump 5, cylinder 5 and ram 1, high pressure relief valve 38. low pressure relief valve 31, throttle valve 33, two pilot operated fom-way valves 39 and 40-and timing valves 4I and 42. The valves 36 and 31 of Fig. 3 and valve I3 of in lVickers 4Patent No. 2,043,453issuedezdune 9,

A pressure conduit 43 leading from pump 5 branches od to the four-way valves 39 and 43 through conduits 44 and 45, respectively. The

right hand side of the pilot operated valve 39 is connected to the timing valve 4I by a conduit 45 leading toa port 41. Phe lefthand side of the valve 39 is connected to the timing valve 43 by a the four-way valve 39 arev connected to the left and right ends of the pilot operated valve 40 by conduits 52 and 53 respectively. An-outlet conduit 54 leadin'gfrom the valve 43 is connected to the cylinder 8 by a conduit 55 and to ports 53 and 51a of the timing valves 4I and 42 respectively. An outlet conduit 53 from the valve 48 leads to the low. pressure relief valve 31 and also to the ports 51 and 55a of the timing valves 4I' and 42- ated valve 45. When tile piston 1 is being lifted pressure passes from the -pump 5 through conduits 43, 45, valve 40, and conduits 54 and 55.`

A valve l0 similar to that described in connection with Fig. 2, may be placed in conduit 45 to prevent the load from `falling in case of power' failure during hoisting. Dln'ing the lowering stroke.' of the piston 1 pressure passesfrom the cylinder 5 tothe tank through conduits 55 and 54, valve 43, conduit and the throttle valve 38. The' rate of the lowering stroke is deter-v mined bythe setting of the throttle valve 38. i Referring now to the timing cycle, assuming that the ram 1 Vis being'lowered, the pressure .55 Fig. 2 arestandard relief valves' such las shown conduit 48 and port 41a.` Outlets 58 and 5I` fr'om lines 43 and 45 are open to the tank through valve, conduit53 and the low pressure relief valve 31. The port- 55a of the'time delay 42 is also exposed to this low back pressure or pilot pressure. When the time setting of the valve e42 expires as the ram 1 reaches its lower-most position, the port 58a of this valve is open to the port 41a so that pilot pressure is directed through theline 48 to the left hand `side of the four-wayvalve 39. This valve 39 is shifted by this pilot pressure so that pilot pressure from the mainpressure line -43 is directed'through the' conduit 52 to the lefth'and side of the four-way valve 43. The latter valve is then shifted so that the delivery of the pump 5 is directed from the conduit 45 to the Amain cylinder 8 through the conduits 54 and 55, thus c ausingthe ram 1 tobe raised'.

- During the raising stroke of this ram, pilot presv sure from the pressure conduit 55 is directed to the port 51a ofthe va1ve 42 to reset the saine.'

This pressure isalso exerted at the port 53 of the timing valve 4I and starts the delay of this valve. This delay controls the time during which a constant delivery of pressure fluid is directed ing cylinder including a shiftable member -hydraulically connected ywith said motor-actuated from the pump 5 to the main cylinder B and there- Icylinder 6 is open to the tank through conduits 55 and 56, valve 4B, conduit 6B and the throttle valve 38 and the ram again starts its lowering stroke.4

The relief valve 3l acts at this time to maintain suicient back pressure to reset the time delay valve di and operate the time delay valve 32, the setting of which determines the length of the downward stroke of the main cylinder. As previously described when the setting of the valve i2 has expired the port 56a is open to the port Bla so that the four-way valves 39 and d can both be shifted to cause the cycle to repeat.

I claim:

l. In a, hydraulic circuit, a timing mechanism for' controlling the operation of pilot pressure comprising a pilot valve, means thereon for operating the same comprising a shaft extending valve and arranged to be shifted concurrently with said motor, and means operably-connecting said member and said valve means whereby shifting of said member eects shifting of said valve means and consequent reversal of said motor actuated valve.

3. In a' hydraulic system, a double acting motor and means for controlling the same comprising a .source of liquid under pressure, a reversible,

therefrom and radial fingers spaced on said shaft,

a timing means comprising a cylinder and piston therein, a rod on said piston, spaced dogs on said rod adapted to contact, respectively, the ngers of said pilot valve, a no w control valve means, and valve means for directing pressure to oneend or the other of said cylinderand for connecting the other end of said cylinder to said dow control valve means whereby the traverse of the piston in said cylinder is limited in time by the setting of said ow control valve.

2. In a hydraulic system, a double acting motor and means for controlling the same comprising a source of liquid under pressure, a reversible, motor-actuated valve hydraulically connected with said motor and 'arranged to direct liquid under pressure' to one side or the other of said motor, a valve means connected with said source and motor-actuated valve shiftable to cause reversing of said motor-actuated valve, and a timmotor-actuated valve hydraulically connected with said motor and arranged to direct liquid under pressure to one side or the other or said motor, a valve means connected with said source and motor-actuated valve shiftable -to cause reversing of said motor-actuated valve, and a timing cylinder including a shiftable member hydraulically connected with said motor-actuated valve and arranged to be shifted concurrently with said motor, means operably vconnecting said lmember and said valve means whereby shifting of said member effects shifting of said valve means and consequent reversal of said motor actuated valve, and means for controlling the rate of flow of liquid from said timingl cylinder whereby the operation of said member is time controlled. y

Kl. In a hydraulic system, a double acting motor and means for controlling the same comprising a source of liquid under pressure, a reversible, motor-actuated valve hydraulically connected with said motor and arr'anged to direct liquid under pressure to one side or the other of said motor, a secondary valve for controlling 4said motor-actuated valve, a timing cylinder, each end cf which is hydraulically connected with 'said motor-actuated valve, a piston in said timing 'cylinder to be shifted concurrently with said motorl operably connected with said secondary valve whereby' a predetermined shifting of said piston in either direction will actuate said secondary valve, a flow control device, and means connecting said now control device with said motormined intervals. I

t HARRY F. VICIGIRS.l

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