US2408799A - Shuttle valve - Google Patents

Description

I Get. 8,1946. J. F. MELICHAR 2,408,799

SHUTTLE VALVE Filed Jan. 50, 1943 Patented Oct. 8, 1946 SHUTTLE VALVE Joseph F. Melichar,

The Parker Appliance Ohio, a corporation of Cleveland, Ohio, assignor to Company, Cleveland,

Ohio

Application January 30, 1943, Serial No. 474,155

2 Claims.

The invention relates generally to valves and has for an object to provide a novel form of valve having two spaced coaxially arranged seats one adapted to communicate with a normal fluid pressure source and the other with an emergency fluid pressure source, a service part disposed intermediately of said seats and adapted to be conneoted with a motor or the like, and a shuttle valve selectively engageable at its ends with the two seats and adapted to be automatically shifted by the normal fluid pressure or the emergency fluid pressure, whichever is dominant, to direct the dominant fluid pressure to said service port.

Valve structures of the general type stated have been provided heretofore, but such structures have been somewhat difilcult and expensive to manufacture and limited in efliciency in operation due to their particular structural designs, and it is a purpose of the present invention to provide an improved valve structure of the type stated in which these defects are eliminated.

An object of the invention is to provide a valve structure of the character stated in which is included a spring detent member engageable with the shiftable valve element for yieldably maintaining shifted positions thereof and mounted in a plug removably secured in a bore in the valve casing coaxially aligned with the service port in the casing thus making it possible to form said port and bore by the making of a straight through bore in the casing, the valve seats also being coaxially aligned so that the chamber in which the valve element is shiftable also can be formed by the making of a straight through bore in the casing intersecting the first mentioned straight through bore.

Another object of the invention is to provide in the improved valve structure a shiftable valve element having non-circular ends disposed to provide pressure fluid flow passages for communicating with the service port and the particular open valve seat, each said end also having a recess in which a ball is loosely retained for self centering seating engagement with the adjacent valve seat.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more fully understood by following the detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

Figure 1 is a somewhat diagrammatic view illustrating one practical manner of using the improved shuttle valve.

Figure 2 is a central longitudinal sectional view illustrating the shuttle valve.

Figure 3 is a detail View of the shuttle valve element per se, one end being shown in section.

Figure 4 is an end elevation of the valve element shown in Figure 3.

Figure 5 is a central longitudinal sectional view of the valve casing.

Figure 6 is an end elevation of the valve casing.

Figure 7 is a view similar to Figure 5 illustrating a slightly modified form of the valve casing.

Figure 8 is a central vertical cross section through the casing illustrated in Figure '7.

In the example of embodiment of the invention herein illustrated, the improved valve structure includes a casing which is substantially cruciform in shape so as to provide a central rectangular main body portion 5 and .two coaxially aligned leg extensions 6, each said leg extension being externally threaded at its end as at 1. The main body portion 5 is provided with a straight through axial bore 8 which is internally threaded at each end as at 9, and the casing also is provided with a straight through bore IE1 extending axially through the leg extensions 6. The bore l0 preferably, but not necessarily, is smaller than the bore 8. See Figures 2, 5 and 6.

A shuttle valve element H is longitudinally, shiftably mounted in the Valve casing and is provided with cylindrical end portions H. which are slide guided in the aligned portions of the bore ID disposed in the respective casing legs 6 in the manner best illustrated in Figure 2. The valve element is shaped in the manner best illustrated in Figures 3 and 4 of the drawing to include a central ridge l3 which is flanked at each side by an annular groove, said grooves forming cam surfaces l4, l4 merging into the central ridge l3. Each cylindrical end of the valve element has external surface portions thereof cut away as at I5 to provide clearances without destroying the guiding contact of the valve element end portions in the respective ends of the guide bore Ill. See Figures 2 and 4. Each end of the valve element also is provided with a cylindrical extension l6 of reduced diameter and which is recessed as at l! to receive a seat engaging ball IS, the end extensions being peened or spun over as at Hi to retain the balls loosely within their receiving recesses. This loose mounting of the seat engaging balls permits each ball to partake of sufficient movement relative to the center of the valve element to assure self centering or perfect seating thereof.

A seat member 20 is removably mounted in each end extremity of the casing bore I0, each said seat member including a cylindrical portion snugly receivable in the respective casing leg end and a flange or head enlargement 22 disposed to abut the respective leg extension end and be removably held thereagainst by a coupling cap 23 threadably mounted on the respective leg extension in the manner clearly illustrated in Figure 2. Each cap 23 may include an externally threaded coniform male coupling element extension 24,

One end of the casing bore 8 provides a service or outlet port, and in the other end of this bore a detent plug 25 is removably mounted. The plug includes a sprin chamber 26 and has a slightly larger ball chamber 21 provided in the cylindrical end extension of the plug which is disposed adjacent the casing bore In and the shuttle valve element slidably mounted therein. A detent ball 28 is yieldably mounted in the ball chamber and projects therefrom into position for yieldably engaging with one or the other of the inclined surfaces I4 on the shuttle valve element II for yieldably holding said element against one or the other of the valve seats 20. As before stated, the seat engaging balls I8 are free to move slightly relative to the valve element I I so as to perfectly seat in and close the respective valve seats 20. At least one aperture 29 is provided in the reduced diameter cylindrical extension of the plug 25 at a point above the ball 28 so as to permit free passage of fluid between the space surrounding said reduced diameter extension and the interior of the plug so as to prevent trapping of pressure fluid in the plug and interference thereof with the free movement of the ball 28.

The valve structure is adaptable to many uses. One practical use is diagrammatically illustrated in Figure l of the drawing in which the service or outlet port of the casing is shown connected as at 30 with a motor or the like intended to be driven by fluid pressure directed thereto through the valve structure. One of the casing legs 6 and the valve seat therein is connected as at 32 in communication with a normal pressure fluid source such as a pump 33. The other casing leg 6 and the valve seat therein is connected as at 34 with an emergency pressure source such as a compressed air tank 35. Cut-off valves 36 may be provided in both of the connecting lines 32 and 34.

Assuming the valve 36 in the connecting line 32 to be open and valve 36 in the connecting line 34 to be closed, pressure fluid from the normal or pump source 33 will enter the valve casing and automatically shift the valve element II to the right, thereby closing the connecting line 34 and opening the connecting line 32. The pressure fluid directed through the connecting line 32 will pass into the bore ID in the connected leg 6 of the casing and will pass into the service port or outlet about the unseated end of the valve element through the clearance I therein and through the connecting line 30 to the motor 3|. Should operation of the pump be discontinued for any reason, the valve 36 in the line 34 can be opened and emergency pressure from the tank 35 will serve to reverse the position of the valve element II and automatically direct emergency pressure fluid through the connectin line 30 to the motor 3 I. It will be obvious that when the normal supply of pressure fluid is again delivered from the pump the shuttle valve will again be shifted torestore the normal operation first described. While it is preferred that the casing bore in which the shuttle valve is guided be smaller than the intersecting bore, the intersecting bores may of course be made of the same or substantially the same diameter. In Figures '7 and 8 of the drawing there is illustrated a slightly modified form of casing structure in which the vertical bore 31 and the intersecting or shuttle valve receiving bore 38 are made of the same or substantially the same diameter. In this form of the invention an undercut or annular passage 39 aligned with the bore 38 may be included, if desired, to provide more flow than would be provided by the ordinary intersection of the bores 31 and 38.

In the foregoing description there is described a valve structure which can be manufactured inexpensively and with great facility, partly due to the fact that the casing is generally cruciform in shape and is provided with intersecting straight through bores effective to provide for the mounting of the coaxially aligned seats and also the service port and the detent plug. The shuttle valve element is very simple in construction and positive in action, the external surface clearances at the respective end of the valve element provide properly controlled communication between the respective valve seats and the service port without disturbing the guiding contact of the valve element ends in the valve bore, and the movably mounted seat engaging balls in the valve element assure perfect seating of the respective valve ends.

It is of course to be understood that the details of structure and the arrangement of parts may be variously changed and modified without departing from the spirit and scope of the invention.

I claim:

1. In a valve of the character described, a casing having a cylindrical bore therethrough with an intermediate enlarged portion concentric thereto and an inlet seat at each end of the bore and a single outlet port communicating with said intermediate enlarged portion, a shuttle valve slidable in the bore and having provision for alternately engaging the seats to open communication between a selected inlet and the outlet port and close the other inlet, said shuttle valve having cylindrical portions engaging the Wall of said bore endwise of said enlarged portion and so spaced apart as to be disengageable from said bore one at a time at said enlargement to open the inlets, said shuttle also having non-circular portions between the seat engaging portions and the cylindricalportions and forming the sole guiding means within the bore for that end of the shuttle which is in open position and defining with said bore clearance spaces through which fluid can freely pass from a selected inlet into the intermediate enlarged portion of the bore and thence to the outlet port.

2. A shuttle valve having a generally cruciform casing presenting an elongated main body and two leg extensions axially aligned with their common axis disposed in right angular relation to the longitudinal center of said main body, said main body having a straight through bore centrally longitudinally thereof and forming a plug chamber at one end and a service port at its other end, said leg extensions having a straight through bore axially thereof and intersecting the firstmentioned bore, a valve seat in each leg extension bore portion, a shuttle valve element slide guided at its ends in said leg bore portions and having provision for alternately engaging and closing one seat and disengaging and opening the other seat, and detent means in the plug chamber engageable with the valve element for yieldably retaining the valve element in one or the other of its shifted positions, said valve element having clearances at each end thereof for opening communication about the unseated end of the valve element and between the service port and the leg bore portion in which said unseated end is guided, the valve element and detent means being so constructed and arranged that communication at an end of the shuttle is opened only after the communication at the other end of the shuttle is closed and after the detent has passed the center of the shuttle.

JOSEPH F. MELICHAR.

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