US2071605A - Hydraulic drive - Google Patents

Description

Feb. 23, 1937. w. c. ANTHONY ET AL 2,071,605

HYDRAULIC DRIVE Filed Dec. 15, 1932 2 Sheets-Sheet l I 72?]672 750716 WQ'ZZZ'QWZ 6. J72 25/2072 6,568?"- Wizokier @QAW 621a.

Feb. 231937. V w. c. ANTHONY ET AL 2,071,605

HYDRAUL I 0 DR IVE Filed Dec. 15, 1932 g Sheets-Sheet 2 Patented Feb. 23, 1937 PATENT OFFICE HYDRAULIC DRIVE William C.

Anthony and Lester Wachter,

Streator, 111., assignors to Anthony Development Company, Streator, 111., a syndicate Application December 15, 1932, Serial No. 647,390

3 Claims.

This invention relates to a hydraulic operating system and to a control therefor. In one form it is exemplified in a hydraulic hoisting mechanism in connection with an elevator which is itself mounted on an automotive vehicle and in which the means for providing the hydraulic pressure is operated by the vehicle engine. This is not an essential part of the invention and the hydraulic pressure and control system may be operated by any source of power and may be mounted in any suitable location.

One of the objects of the invention is, therefore, to provide a simple, unitary control for the operation of the hydraulic drive. Another object is to provide such a control in connection with a hydraulic hoisting mechanism.

Other objects will appear from time to time in the specification and claims.

Our invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:-

Figure 1 is a side elevation of a portion of the vehicle and an associated hoisting mechanism upon it;

Figure 2 is a partial plan view of the same;

Figure 3 is a diagrammatic showing of the hydraulic system;

Figure 4 is a sectional view on an enlarged scale illustrating the control valve;

Figure 5 is a sectional detail taken at line 5:-5 of Figure 4;

Figure 6 is an elevation with parts in section and parts broken away, illustrating the control for the valve mechanism.

Like parts are designated by like characters throughout the specification and drawings.

A illustrates generally a vehicle, B a portion of a hoisting mechanism, and C a track, along which a portion of the drive for the hoisting mechanism is arranged to run. D is a pressure cylinder within which a piston D is arranged to move. D is a piston rod extending outwardly beyond the closed end D of the cylinder D and carrying at its outer end the dolly D which runs in the track and to which the hoisting cable or any other mechanism which is to be operated may be attached.- The details of this mechanism and its attachment form no particular part of the present invention. The piston D is perforated as at D and through the perforation the stem D of a valve D is positioned. A spring D about the valve stem D normally holds the valve seated so as to prevent leakage or escape of fluid through the piston. When the piston has moved sufiiciently to the left, as shown in Figure 3, the stem D contacts the head D of the cylinder and if movement of the piston continues, the spring D is compressed and the valve is unseated to permit escape through the opening D and to permit discharge of fluid through the discharge opening D of the cylinder D.

E is a shaft driven from any suitable power source, in the present case driven by the engine of the vehicle. It may be carried on any suitable bearings. From it a pump E is driven. This pump may be of any design, preferably a rotary gear pump, although other types of pumps may be used. The details of the pump form no particular part of the present invention. The pump is connected to a reservoir or tank E An intake opening E furnishes communication for the pump with the tank, so that fluid being pumped from the tank is drawn from the intake opening E leading from the tank. It is discharged from the outlet or discharge passage E under pressure along a conduit E which lies for a portion of its length within the reservoir housing E. E is a safety release valve in the path of the pressure. It includes a ball valve E and a spring E which is adjustable by means of the holding member E Excess pressure within the pressure line E overcomes the resistance of the spring E unseats the ball and permits discharge directly from the pas- I sage E back into the reservoir E through the outlet opening E F is a housing which encloses the control elements. To it the conduit or pressure line E is connected and from it the pressure line or conduit F discharges through the opening F into the cylinder D. Within the housing F is formed a chamber G having an outlet opening G and a second outlet opening G The outlet G discharges into a chamber G within the housing F, which is provided with an outlet port G to which a return pipe G is connected. This return pipe discharges into the reservoir E through the connection opening G. A short connection G communicates between the discharge port D of the cylinder D and the return pipe G The connection G" is to permit escape of fluid from the left hand side of the cylinder D back into the return pipe G This escape is necessary when the piston D is moved to the left from the position shown, for example, in Figure 3. Ordinarily the piston, having once been moved to the left, will be returned to the right by a pull on the rod D which may be exerted by a load on the cable B. A valve cage G is positioned partially within the chamber G and partially within the outlet opening G Within it a ball 6' is positioned. A bearing plate (3 contacts the ball and serves as an abutment for a spring G" which is itself held in place by a pin G which is positioned in the cage G". A push member G" is arranged within the reduced end G of the cage (3 and may be made of any suitable shape. In the form here shown it has a flattened end or head G and is provided with guiding vanes which leave open spaces sufficient to permit the passage of fluid freely through the discharge opening G when the ball is unseated.

H is another chamber in the housing F. It communicates with the chamber G through the opening G A valve cage and assembly H identical with that just described, is provided to control the passage G a spring I-I normally holding the ball H seated. A discharge outlet H is provided from the chamber H into the chamber Ci and it likewise is controlled by a similar ball valve H which is ordinarily normally held seated by a spring H The ball H may be unseated by a pushermember H which is preferably identical in design and shape with the member G G described above.

As a means for controlling these valves and the discharge from the chambers G and H, there is provided a shaft or rod I which extends outwardly from the housing and has an operating handle I by means of which it may be rotated or otherwise moved. The shaft I is carried in any suitable bearings and has formed on it, preferably removably, a contact member I which as here shown forms the head of a rivet I which latter is positioned in a suitable hole formed in the shaft I. The member I may contact the head (3 of the push member G A similar rivet head 1 formed on a rivet 1 serves as a contact member for the part H The pusher members controlling the ball valves G and H may be controlled so as to open or to permit these valves to close by movement of the shaft I. One end of the shaft I projects outside of the housing F as indicated in Figures 4 and 6. A plate or other suitable member I is fastened to the handle I and carries a pin 1 which projects into a preferably curved slot I in a housing member I The plate I is provided with a plurality of indentations 1 The housing I is provided with a hollow J threaded as at J at one end and provided with a reduced bore J atits opposite end. A plunger J having an enlarged head J and a rounded exterior end J is mounted within the hollow J. A compression spring J is positioned within the housing, bears at one end upon the portion J of the plunger J and at its other end upon an adjustable threaded plug J" which closes the hollow portion of the hollow J. This structure furnishes a friction device for retaining the handle I in any position to which the operator may move it. It prevents accidental movement of the handle but by reason of the yielding of the spring it permits movement of the handle whenever the operator applies sufficient force to it to move it positively.

It will be realized that whereas we have herewith shown and described a practical operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of our invention and we wish, therefore, that our showing be taken as in a sense diagrammatic. In particular the pressure by-pass valve formed generally of the members E", E 1:? and E might be changed and any other relief of this sort might be used. The importance of using such a valve is to prevent overloading of the system. If, for example, as shown, the system is applied to a hoist or shovel and if an excessive load is taken into the shovel or if for any other reason an excessive load comes upon the hoisting mechanism, the pressures developed within the hydraulic system might become excessive and might damage some part of the system. To prevent this the by-pass relief is used. When pressure builds up to a. dangerous point, the spring E yields to permit unseating of the ball valve E and thereafter operation of the pump merely cir culates fluid, drawing it from the reservoir E through the intake passage E forcing it from the pump through the outlet port E the passage E the valve housing E and back into the reservoir.

The use and operation of the invention are as follows:

In ordinary use the pump or other source of fluid pressure operates continuously or substantially continuously so that there is circulation of fluid under pressure from the reservoir through the pump to the control valve housing F. The handle I is manipulated to control the discharge of fluid from the housing F. If the piston is to be forced inwardly, so as to move the dolly D to the left as shown in Figure 3, the control is so moved that fluid under pressure passes from the conduit F through the opening F into the cylinder and forces the piston to ,the left. When this motion has proceeded as far as is desired the control is changed and fluid is then returned through the outlet opening G along the line G back to the reservoir E Frequently in digging or lifting, and in other operations, it is desirable to maintain the piston at a fixed point after having moved it. This means that first pressure is directed from the housing F through the pipe F to move the piston. When the piston has moved sufficiently, no further'pressure is directed in this direction, but the pressure which has moved the piston is not released so that the piston is held in position and pressure or fluid under pressure moving into the housing F through the pipe E is merely short circuited through the housing F and out of the pipe G When it is desired to return the piston, for example in hoisting to permit it to be withdrawn from the cylinder, then the control within the housing F is so manipulated that fluid may be forced backward from the cylinder through the pipe F and back from the housing F through the pipe G to the reservoir. There are thus preferably three settings for the controls within the housing F, one, in which the fluid moving through the housing moves directly to the cylinder so as to move the piston; two, in which the fluid which has passed from the housing to the cylinder is held in the cylinder and in which further fluid entering the housing F is discharged from it back to the reservoir; and, three, that in which the fluid which has entered the cylinder is forced backward from it into the housing F and in which at the same time further fluid entering the housing F under pressure is conducted directly back through the pipe Ct to the reservoir.

Considering now the operation of the control elements within the housing F. In one position the shaft I is moved so that the contact mem-. bers P and 1* are out of contact with the pushers which unseat the balls G and H They are of the hoisting mechanism under excessive loads thus seated both by the springs and by pressure within the housing. Fluid under pressure now enters the housing through the pipe E and since the balls (3* and H are seated, but since the ball H is outward opening, pressure within the chamber G of the housing F unseats the ball H passes through the chamber H, through the pipe F to the cylinder. Such a seating of the parts would be used for hoisting.

After suflicient hoisting has taken place, the shaft I is moved so that the contact member I strikes the head G" of the pusher and unseats the ball (3. Fluid entering the chamber G thereafter passes at once through the opening G into the chamber G and through the outlet G and the pipe G back to the reservoir, but fluid under pressure within the cylinder and the pipe F is retained because it merely serves to seat the balls H and H When now it is desired to lower the hoisting load or to permit the piston to return, fluid must be allowed to escape from the cylinder. This is done by a further movement of the shaft 1, which while retaining the contact member I in position to move the pusher to hold the ball G unseated, also brings the contact member I in contact with the pusher which is effective on the ball H and unseats it. This fluid under pressure within the cylinder and the pipe F? can now be forced back by the piston which may be pulled to the right by the load attached to the piston rod D? through the chamber H, into the chamber G and outward through the port G and the pipe G back to the reservoir- In this movement it is, of course, joined by further fluid which has come under pressure from the pump to the housing F through the chamber G past the open ball G through the chamber G and the port G I Thus the movement of the shaft I into three positions will either direct all of the fluid into ervoir, or will release the fluid held in the cylin-- der and direct further fluid back to the reser-' voir, so that in the case of a hoist, for example, with the pressure source continually operating to furnish pressure, a load may be raised, held in position and lowered at the will of the operator by moving a single control to any one of three predetermined positions.

As a safeguard against over-loading and damage to the system because of'excess pressures from that or any other cause, the pressure bypass valve illustrated in Figure 3 is used. If for any reason expess pressures develop in the system, the pressure within the pipe E leading from the pump, will become suflicient to compress the spring E thus permitting the ball valve E to become unseated and fluid coming from the pump will be by-passed directly through the valve housing E to the reservoir and further pressure will not be built up within the cylinder D or elsewhere in the system where damage might result. This, among other things, has the efiect of acting as an automatic stop for hoisting or other movement of the mechanism. If the apparatus is applied to a shovel into which excessive load is taken, pressures will build up and will cause the automatic by-pass to operate so that the hoist will not be moved. Thus the mechanism serves as a check against the taking of excessive loads and as a safety check or throw-out to prevent the creation of excessive pressures and to make impossible the operating and generally as a safety check for the prevention of damage in the system.

We claim: 4 1. In combination in a hydraulic control apparatus, a housing, a supply conduit communicating with the interior of said housing, for introducing thereto pressure fluid, a cylinder, a conduit from said housing to said cylinder, a return conduit from said housing, a partition within said hous-' ing, a plurality of openings therethrough, a ball check valve for each opening adapted normally to close it, push rods for said ball check valves positioned wholly within said housing, a control member positioned partially outside of and partially within said housing, extending into said housing and provided with separate contact parts, one for each of said push rods, said contact parts being mounted on that portion of the control member which lies within the housing, an automatic ball check valve positioned within the housing and within the path of fluid from said supply conduitto said cylinder, and outside of the conduit from said housing to said cylinder, one of said first mentioned ball check valves effective, when open, to cause fluid entering the housing to be by-passed away from said cylinder conduit, to

pass through the partition and to be discharged from the housing through said return conduit, another of said ball check valves, when open, effective to cause fluid to return from said cylinder, to pass through said housing and to be discharged therefrom into the return conduit.

2. In combination in a hydraulic control apparatus, a housing, a supply conduit communicating with the interior of said housing, for introducing thereto pressure fluid, a cylinder, a conduit from said housing to said cylinder, a return conduit from said housing, a partition within said housing, a plurality of openings therethrough, a ball check valve for each opening, adapted normally to close it, push rods for said ball check valves positioned wholly within said housing, a control member positioned partially outside of and partially within said housing, extending into said housing and provided with separate contact parts, one for each of said push rods, said contact parts being mounted on that portion of the control member which lies within the housing, an automatic ball check valve positioned within the housing and within the path of fluid from said supply conduit to said cylinder, and outside of the conduit from said housing to said cylinder, one of said first mentioned ball check valves effective, when open, to cause fluid entering the housing to be bypassed away from said cylinder conduit, to pass through the partition and to be discharged from the housing through said return conduit, another of said ball check valves, when open, effective to cause fluid to return from said cylinder, to pass through said housing and to be discharged therefrom into the return conduit, the contact parts on said control member positioned to cause one or both of said push rods to move to open one or a chamber in communication with said return conduit, said by-pass or inlet chamber and said return fluid chamber being provided with ports communicating with the discharge chamber, a check valve for the port associated with the inlet chamber, a check valve for the other port, and means for normally closing said valves, valve actuating means for each of said check valves positioned wholly within said housing, a control member extending exteriorly of the housing and having a portion thereof disposed within the housing in operative relation to said valve actuating means, said last-mentioned portion of the control member being provided with means for selectively and operatively engaging said valve actuating means, a check valve positioned within the return conduit.

WILLIAM C. ANTHONY. LESTER WACH'I'ER.

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