Title:
MANUALLY OPERATED DUAL PRESSURE DELIVERY CONTROL VALVE
United States Patent 3630234


Abstract:
A manually operated fluid pressure control valve including a camshaft movable by a handle among a plurality of positions, said camshaft carrying cams engageable with valve-operating plungers in preselected relationship to move normally closed valve elements to open position, at least one of said valve elements responding to pressure-reducing mechanism on the delivery side of said element whereby said control valve delivers from a common source of fluid pressure fluid at different pressures simultaneously or separately in response to movement of said handle.



Inventors:
HOFFMAN DAVID A
Application Number:
05/001754
Publication Date:
12/28/1971
Filing Date:
01/09/1970
Assignee:
BENDIX-WESTINGHOUSE AUTOMTIVE AIR BRAKE CO.
Primary Class:
Other Classes:
137/116.5, 137/505.12, 251/113
International Classes:
B60T13/14; B60T15/04; (IPC1-7): G05D16/10; F16K11/14
Field of Search:
137/609,601,495,614
View Patent Images:
US Patent References:
3128635Multi-characteristic valve device1964-04-14Doolittle
3042063Distributing device1962-07-03Guinard
2620195Valve for pneumatic columns1952-12-02Gillerstrom
2148305Throttle controlling mechanism1939-02-21Sanford



Primary Examiner:
Nelson, Cary M.
Assistant Examiner:
Gerard, Richard
Claims:
What is claimed is

1. A fluid pressure control valve comprising a housing, a manifold in said housing connected to a source of fluid pressure, a plurality of valve chambers connected in parallel with said manifold, a plurality of delivery chambers connected with the respective valve chambers, a normally closed valve element disconnecting each of the valve chambers from its delivery chamber, plunger means in axial alignment with said valve elements for controlling the operation of the latter, an operating shaft arranged in transverse relationship with respect to said plunger means, a handle attached to said operating shaft, cam means carried by said shaft for operating said plunger means, said cam means being constructed and arranged that in one position of said handle said cam means are spaced from said plunger means and said valve elements are in their normal closed position, in a second position said cam means is operable on one of said plunger means to open the valve element controlled thereby, and in another position of said handle all of said plunger means are movable by said cam means to move all of said valve elements to their open position, a graduating spring between at least one of said plunger means and said cam means, said last-named plunger means including a fluid pressure responsive piston in one of said delivery chambers subjected to the pressure admitted through its valve element upon opening thereof to exert a pressure force on said piston opposing the force of said spring and to move said piston to a position wherein said last-named valve element closes whereby a predetermined pressure is maintained in the last-named delivery chamber, and a spring-loaded manually releasable locking means cooperating with said shaft for releasably locking said shaft in at least one of its positions.

Description:
This invention relates to manually operated fluid pressure control valves.

Where fluid pressure is relied upon for operating certain primary mechanisms, as for example, the fluid pressure brakes on a tractor-trailer automotive vehicle, it is often desirable that fluid pressure also be available for operating a number of different accessory devices, some of which respond to relatively low pressure on the order, say, of 4 p.s.i., while others require an intermediate pressure of say, 30 p.s.i. An object of the invention is to provide a manually operated control valve for selectively delivering to separate delivery ports by manipulation of a single handle different fluid pressures derived from a common source of fluid pressure.

In accordance with the invention, main reservoir pressure on the order, say, of 110 p.s.i., passes through a reducing valve which reduces the pressure to that of the intermediate accessory pressure of 30 p.s.i. This reduced pressure is fed to a manifold which has connected thereto, in parallel, a pair of valve chambers, each containing a normally closed valve spring biased toward its closed position. Cam-operated plunger means each containing an exhaust passage may be moved against the respective valve elements to close off the exhaust passages and thereafter move the valve elements to open position whereupon fluid flows to respective delivery ports to the devices to be actuated. The plungers are operated by cams carried by a shaft having a handle which in a first position effects closing of the valves. The cam lobes are arranged that in another position of the handle both valve elements are opened and when the handle is in yet another position only one of the valve elements is opened. The pressure delivered by one valve element is at manifold pressure while the pressure delivered by the other is at a reduced pressure as will be apparent hereinafter.

Referring now to the drawings:

FIG. 1 is a top plan view partly broken away and partly in section of the valve of the invention;

FIG. 2 is a vertical cross-sectional view taken substantially on the line 2--2 of FIG. 1; and

FIG. 3 is a vertical cross-sectional view taken substantially on the line 3--3 of FIG. 1.

Referring now to the drawings the numeral 10 designates a valve casing having an inlet port 12 which is connected to a source of high pressure such as the main fluid pressure reservoir of a tractor-trailer combination. The port 12 opens into an inlet passage 14 which is connected to a pressure-reducing cavity 16 through a valve seat 18 controlled by a valve element 20 which is urged at all times by a spring 22 toward the valve seat 18. The upper side of the pressure-reducing cavity 16 is defined by the lower side of a piston 24 having an integral plunger 26 containing an exhaust passage 28 which communicates with atmosphere by way of an exhaust opening 30 in a closure member 32, an exhaust cavity 33 having a cover 34 thereover, and a baffled exhaust port 35. Confined between the closure member 32 and the piston 24 is a control spring 36 which yields when a predetermined pressure has been delivered to the cavity 16 to move the piston upwardly against the downward force of the spring 36 until the valve element 20 laps the inlet valve seat 18 and the lower end of the exhaust plunger 26 to trap in the cavity 16 the desired pressure which determines the intermediate pressure to be selectively delivered by the valve of the invention.

The cavity 16 is connected to a first valve chamber 38 by way of a passage 40 and the valve chamber 38 in turn is connected to a second valve chamber 42 by way of a passage 44, the chambers 38, 42 and passages 40, 44 defining a manifold containing fluid at the predetermined intermediate pressure as determined by the pressure-reducing piston 24. Within the valve chambers 38, 42 are respective valve elements 46, 48 which are normally urged into closed position against the respective valve seats 50, 52 by springs 54, 56.

In axial alignment with the valve element 46 is a plunger 58 containing an exhaust passage 60 with the lower end of the plunger being urged away from the valve element 46 by a spring 62, it being noted that the exhaust passage 60 communicates with atmosphere by way of the exhaust chamber 33 and exhaust port 35. The spring 62 operates in a delivery cavity 66 which communicates with a device to be actuated by way of a delivery port 68. The spring 62 operates against a shoulder on the plunger 58 to urge the upper end of the plunger against the surface of a cam 70 carried on an operating shaft 72 journaled at one end 73 in a suitable recess 74 in the housing 10 and at the opposite end through a necked part 75 of the housing as particularly seen in FIG. 1. The shaft 72 projects outwardly beyond the necked part 75 and carries at its outer end a handle 76.

The second valve element 48 and its cooperating valve seat 52 control the flow of fluid from the manifold, defined by passages 40, 44 to a second delivery chamber 78 connected to a delivery port 79. The upper end of the chamber 78 is defined by the lower surface of a pressure-reducing piston 80 which is urged at all times upwardly by a spring 81 to retain the lower end of a plunger 82 containing an exhaust passage 84 clear of the upper side of the valve element 48. The exhaust passage 84 leads into a cup-shaped recess 86 on the upper side of the piston 80 and contained within the recess 86 is a graduating spring 88 which operates between the bottom of the recess and a movable abutment 90 having suitable slots 91 therethrough to connect the recess 86 with the exhaust cavity 33. The abutment is urged at all times by the spring 88 upwardly toward a second cam 92 carried by the shaft 74 and a snapring 94 is engageable by a shoulder on the abutment 90 to serve as a limit stop for its upward movement.

The cam 92 is desirably provided with two angularly related lobes of equal radial extent whereby when the handle 76 is moved from its horizontal position to a first angular position indicated by the phantom line 76' in FIG. 3, the first lobe on the cam 92 engages the slidable abutment 90 to move this downwardly against the spring 88 which in turn acts on the piston and plunger 82 to move the latter against the valve 48 to first close off the exhaust passage 84 and thereafter open the valve 48 to admit fluid pressure from the manifold 40, 42 to the delivery cavity 78 beneath the piston 80. When the pressure in the cavity 78 has reached a level determined by the area of the piston 80 and the strength of the spring 88, the piston 80 is moved upwardly against the spring 88 until the valve 48 laps the lower end of the exhaust passage and the inlet valve seat 52 whereupon a reduced pressure, which may be on the order of 4 p.s.i. is delivered through the delivery port 79 to the device connected thereto.

The first cam 70 may be so constructed that during the preceding operation it does not affect the first-mentioned plunger 58. However, the cam 70 may have a lobe which is parallel to the second lobe on the cam 92 so that when the handle 76 is moved to its third position, indicated by the numeral 76", the cams 70, 92 respectively depress the plunger 58 and the abutment 90 so that pressure-reducing valve element 48 is operated as already described and the first valve element 46 is opened to effect simultaneous delivery of manifold pressure and reduced pressure to the respective delivery ports 68 and 79. It will be noted that in the case of the valve element 46 that when it is moved to open position it remains in open position so long as the cam 70 is acting on the plunger 58 to move it to its depressed condition. In other words, there is no pressure reduction between the manifold 40, 44 and the first delivery port 68.

With reference now to FIGS. 1 and 3, the valve of the invention is provided with a spring-loaded lock shaft 96 which is urged at all times by a spring 98 to the position of FIG. 1 wherein an arm 100 carried by the lock shaft resides in a circumferential slot 102 on a camlike member 104 carried by the shaft 72. The slot 102 is of sufficient circumferential extent to permit the handle 76 to be moved from its first horizontal valve-off position to its second position 76' wherein the second valve element 48 is moved to its open position to deliver a reduced pressure from the manifold 40, 44. When the handle is to be moved from its second position 76' to its third position 76" wherein both valves are open, in order to ensure that the combined forces of the return springs acting on the cams do not inadvertently rotate the shaft 72 to a position effecting closing of the valve elements 46, 48 the camshaft is locked in its third position by depressing the plunger 96 to bring the arm 100 clear of the first circumferential slot 102 until the handle has been moved to its third position wherein a second slot 106 registers with the arm 100 and upon release of the plunger 96 the arm moves into the slot 106 to positively lock the camshaft 72 in its third position. Obviously, when the handle is to be moved from its third to its second position the plunger 96 must again be depressed until the arm 100 clears the slot 106.

From the foregoing description it will be apparent that the invention has provided a simplified, manually operable valve for supplying either simultaneously or separately different pressures from a common pressure source through the manipulation of a single handle.