US2787255A - Pressure fluid distributor valves - Google Patents

Description

APril 2, 1957 r J. MERCIER ETAL 2,787,255

PRESSURE FLUID DISTRIBUTOR VALVES Filed Jan. 14, 1948 INVENTORS: dsa/v Mews/a? BY @6996 Ava SNEAK @ZW, M

KITTM/YEKS'.

A 2,787,255 Ice Patented Apr. 2, 1957 PRESSURE FLUID DISTRIBUTOR VALVES Jean Mercier, New York, N. Y., and Pierre Guillaume Joseph Marie Audcmar, La Garenne-Colombes, France; said Audemar assignor to Olaer Marine, Paris, France, a company of France Application January 14, 1943, Serial No. 2,286

Claims priority, application Luxembourg January 22, 1947 4 Claims. (Cl. 121-465) This invention relates to pressure fiuid distributor valves comprising two coaxially aligned valves permitting a precise and undelayed opening and closing of. ports or orifices controlled thereby and this Whatever may be the fluid used or the circuit in which the distributor is inserted.

In known distributors of this kind, the two coaxial valves are mounted within a valve casing coaxially therewith, whereby the movable member of one of the valves forms the seat for the movable member of the other valve, the displacements of which are guided by an inner wall portion of the valve casing in such a manner that this other movable valve member will engage its seat in a more or less well centered position. When the two valves are mounted within a valve casing so that their axial displacements are guided by the casing itself, it will be necessary either to produce precise machined guiding surfaces for maintaining the two valves always in coaxial relation, or to provide for a transverse play permitting one of the valves to seat perfectly on the other valve when either one of the valves returns to its closed position; it is diflficult to determine in advance the exact amount of transverse play permitting the valves to centre themselves on the respective seat during return movement into closed position since a too small play may be insufficient whereas a too great play may cause undesirable leakage; thus, the provision of a predetermined transverse play may be considered as a trial and error method, that is, the chosen amount of transverse play may be satisfactory in one case and unsatisfactory in another case.

The object of the present invention is to remedy these drawbacks and to provide for precision alignment of the movable valve members regardless of their transverse play or the machining of their guiding surfaces, thereby improving the structure of the distributor valve, facilitating production and minimizing expense.

Two distributor valve constructions according to the invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 represents a longitudinal section of one form of construction of a distributor valve in accordance with the invention;

Figure 2 shows a modified construction of the distributor valve as applied to a pressure reducing valve;

Figure 3 shows a fluid pressure control system embodying two distributor valves according to the invention.

Referring to the drawings and firstly to Figure l, the distributor valve comprises a cylindrical body or valve casing 1 divided into two parts by means of a partition or transverse wall 2 provided with an axial bore 3, in which is slidably mounted a tubular member 4 projecting into the cylinder space 1b at the right side of partition 2 and having a portion of reduced external diameter 5 which extends towards the cylinder space In at the left side of partition 2. The extremity of said portion 5 of the tubular member 4 has the shape of a bevelled head 6, which co-operates with a valve seat 7 formed by an edge of bore 3 to constitute the closure member of the intake valve of the distributor. The closure member of the discharge valve of the distributor is constituted by a cap 8 comprising an inwardly projecting annular flange 9 having a sliding fit on the free end of tubular member 4, radial ports 10 establishing a communication between the interior of cap 8 and the cylinder space 15, and an inner bevelled surface 11 extending from the inner bottom surface of the cap to the ports 10 and cooperating with a valve seat formed by the corresponding edge of tubular member 4. The portion of the bore 3 located between the larger diameter portion of tubular member 4 and the head 6 when the valve is closed is in communication with a suitable source of pressure fluid, whereas the cylinder space 1a communicates with a space containing the controlled member of a fluid pressure mechanism (not shown). The cylinder space 1b communicates with the exhaust. A piston-like extension 12 projecting out from the valve casing through an axial opening formed in a wall of body 1. bears against the outer bottom surface of cap 8 and a valve actuating, member having the form of a lever 13 pivoted at 1-4 to the body 1 is in abutting contact with piston 12.

This distributor operates as follows:

In the position shown in Fig. l, the pressure fluid mechanism to be controlled by means of the distributor is disconnected both from the pressure fluid supply and the exhaust. When it is desired to connect said pressure fluid mechanism with the pressure fluid supply, it is suflicient to pivot lever 13 to the left so as to open the intake valve of the distributor. To interrupt the supply of pres sure fluid, it is sufiicient to return lever 13 to its position represented in Fig. 1 whereby the pressure in cylinder space 1a, due to a force acting on the 'servomotor or other controlled member operated by the fluid pressure mechanism, will maintain the valve assembly 4-8 in contact with lever 13. It is of course possible to provide spring means arranged so as to constantly urge the intake valve towards its closed position. Finally, to connect the controlled fluid pressure mechanism with the exhaust,-it is sufficient to pivot lever 13 to the right, the intake valve being then maintained in its closed position by the fluid pressure prevailing in cylinder space In and the closure member 8 of the discharge valve moving from its seat by reason of the pressure in space In, a communication is established between cylinder space 1a and the exhaust through the axial passage within tubular member 4, the space within cap 8, radial ports 10, and cylinder space 111.

Since the opening and closing of the valve is made against certain resistances due to the fluid pressure prevaib ing at the inlet and outlet of the distributor valve, means may be provided to balance these pressures. Such means may be constituted by a chamber 15 formed within body 1 of the distributor and communicating with the cylinder space 1a through a conduit 16. A wall of chamber 15 is provided with an axial bore in which is slidably mounted a piston 17 having its outer face in abutting contact with lever 13 at the side thereof opposite piston i2. Therefore, and due to the form given to the valves, the pressures acting on both sides of the closure member ti of the intake are balanced as the areas acted upon by these pressures in one direction are equal to the areas acted upon by these pressures in the opposite direction.

Figure 2 illustrates a second embodiment of the valve assembly of the distributor according to the invention as applied to a pressure reducing valve. This pressure reducing valve is constituted by a body having substantially the same form as that of the distributor described with reference to Figure l and comprises a valve assembly constituted by a tubular member '20 and a cap 21.

'f p g 2,787,265

The tubular member 20 provides an axial passage 22 and has a bevelled head 23 which constituted the intake or admission valve closure member adapted to cooperate with a seat 24 formed in the body of the pressure reducing valve. The cap 21 covers the other end of tubular member 20 so as to be guided thereon. The rim 25 of the cap 21 has a bevel shape and cooperates with a valve seat 26 to form the discharge valve, said seat 26 being constituted by the corresponding edge of a part of larger diameter of the tubular member 20. The tubular member 20 is provided, in the part covered by the cap 21, with transverse passages 27. A tappet 28, subjected to the action of a spring 29, is in abutting contact with the outer bottom surface of cap 21. The stem of tappet 28 passes through an end wall of the valve casing in order to avoid counter-pressure, while a passage 3!) permits the flow of pressure fluid from one side of the tappet 28 to the other side thereof.

This pressure reducing valve operates as follows:

The pressure of spring 29 opens the admission valve and the pressure fluid passes from a fluid pressure supply conduit 30 into a conduit 31 which leads to a suitable fluid pressure mechanism (not shown). When the fluid pressure in conduit 31 exceeds a predetermined limit, it displaces the movable valve members 23 and 21 to the right so as to close the admission valve, the critical pressure being determined by the resistance of spring 29. The excess pressure acts upon the inner bottom surface of cap 21 and overcomes the pressure of spring 29 to permit discharge of pressure fluid through the discharge valve and exhaust conduit 32. There is only a very small difference between the pressures of opening and closing determined by the surfaces of the above mentioned valve bearings.

It will be seen that a pressure reducing valve of the type described is extremely simple in design and reliable in operation, and that the movable members on displace ment encounter no resistance except that of spring 29 which is calculated to determine the operating pressure of the fluid. The construction of the pressure reducing valve is substantially similar to that of the distributor described with reference to Figure 1 and otters the same advantages.

In Figure 3, there is shown a hydraulic control system incorporating two distributor valves operating as described with reference to Figure l, the construction of the two aligned valves being substantially the same as that shown in Figure 2. The hydraulic control system comprises a controlled element constituted by a hydraulic motor M and a control element constituted by a lever 40 pivoted at 41 to the body of a control device including two distributors D1 and D2. Distributor D1 comprises an inlet valve 42 and an outlet valve 43, and distributor D2 an inlet valve 44 and an outlet valve 45. The inlet valve 42 of distributor D1 controls the communication between a pressure liquid supply conduit 46 and a conduit 47 leading to the left side of motor M, whereas the inlet valve 44 of distributor D2 controls the communication between said supply conduit 46 and a conduit 43 leading to the right side of motor M. The outlet valve 43 of distributor D1 controls the communication between the conduit 47 and a discharge or exhaust conduit 49, and the outlet valve 45 of distributor D2 the communication between the conduit 48 and said discharge conduit 49. The inlet valves 42 and 44 are constantly urged towards their corresponding seats by spring members 50 and 51, respectively, and the outlet valve 45 of distributor D2 is maintained in abutting contact with the rod of a piston 52 mounted in a cylindrical chamber formed in the body of distributor D2. The space 57 of this cylindrical chamber at the right side of piston 52 may be connected through ducts 53, 54 and 55 and distributor D1 either with the pressure liquid supply conduit 46 or with the discharge conduit 49. A spring 56 is arranged 4 in the cylindrical chamber to urge piston 52 constantly towards the outlet valve 45.

The operation of the control system can be easily understood:

When the lever 40 occupies the position shown in Fig, 3, the pressure liquid supplied through the conduit 46 fiows through the open inlet valve 44 of distributor D2 and conduit 48 to the right side of motor M, while the left side of. this motor is connected, through conduit 47 and the open outlet valve 43 of distributor D1, with the discharge conduit 49. But when the upper end of lever 4t) is displaced from left to right so as to close the outlet valve 43 of distributor D1 to thereby interrupt the communication between the left side of motor M and the discharge conduit 42, the liquid coming from the left side of motor M will fiow through the ducts 55, 54 and 53 into the space 57 of the cylindrical chamber containing the piston 52 so as to push the latter against the action of spring 56 toward the outer end of the cylindrical chamber. Spring 51 is thus allowed to close the inlet valve 44 of distributor D2 so that the two distributors of the control device are in neutral, i. e. closed position. When lever 40 is further actuated to open the inlet valve 42 of distributor D1 in order to connect the left side of motor M and the space 57 of the auxiliary chamber of distributor D2 with the pressure liquid supply conduit 46, the piston 52 will be further displaced to the left to allow the outlet valve 45 of distributor D2 to open under the action of the pressure liquid coming from the right side of motor M so that this liquid can discharge through conduit 49.

As it has been mentioned above, the improved distributor valves according to the invention may be used with any pressure fluid and any circuit, but are particularly applicable to be used as pressure reducing valves and in hydraulic transmission or control systems comprising a slave unit with a followup action to bring the movable member of the slave unit to a position corresponding exactly to that occupied by a valve actuating member, the distributor valves permitting not only to reproduce exactly the displacements of the movable part of the distributor by the slave unit with an absolute precision and without any time lag, but also to ensure at all times a perfect fluidtight closing of the aligned valves due to their exact concentricity with respect to each other.

We claim:

1. A three direction hydraulic distributor Without backlash comprising a housing forming a generally cylindrical chamber having intermediate its ends a part of reduced diameter, an elongated member of still smaller diameter coaxially displaceable in said chamber and having intermediate its ends a part of larger diameter slidably fitted into one end of said part of smaller diameter of the chamber and projecting in each position thereof from said end of said part of smaller diameter of the chamber, a bevelled head on the end of said displaceable member projecting from the other end of said part of smaller diameter of the chamber and cooperating with the adjacent edge of said part of smaller diameter to form a first valve, said elongated member being provided with an axial passage therethrough, a cap slidably mounted on the opposite end of said elongated member so as to be guided thereby for axial displacement with respect to said elongated member, said cap having an inner bevelled surface cooperating with the edge of the part of larger diameter of said dispiaceable member projecting from the part of smaller diameter of said chamber to form a second valve, passages being provided for the flow of pressure fluid between said axial passage and the space in said cylindrical chamber occupied by said cap when said second valve is open, a port opening into the smaller diameter part of said chamber between the larger diameter part and the bevelled head of said displaceable member, a second port opening into the larger diameter are 7,255

part of said chamber occupied by said cap, and a third port opening into the larger diameter part of said cylindrical chamber into which said bevelled head of said displaceable member projects and means acting on the outer bottom surface of said cap to govern the operation of the distributor.

2. A distributor, as claimed in claim 1, for controlling the flow rate of a hydraulic fluid in response to the adjustment of an operating member, including resilient means acting on said displaceable member to bias it to a neutral position in which said first valve is closed, said governing means acting on the outer bottom surface of said cap being connected to and controlled by said operating member.

3. A distributor according to claim 1, operating as a drain-pressure reducing valve and including as governing means acting on the outer bottom surface of said cap a tappet and a spring urging said tappet to a position in which it keeps the second valve closed, the force of said spring determining the pressure reduction to be eifected.

4. A distributor, comprising a housing forming a generally cylindrical chamber having intermediate its ends a part of reduced diameter, an elongated member of still smaller diameter coaxially displaceable in said chamber and having intermediate its ends a part oflarger diameter slidably fitted into one end of said part of smaller diameter of the chamber and projecting in each position thereof from said end of said part of. smaller diameter of the chamber, a bevelled head on the end of said displaceable member projecting from the other end of said part of smaller diameter of the chamber and cooperating with the adjacent edge of said part of smaller diameter to form a first valve, said elongated member being provided sure fluid between said axial passage and the space in said cylindrical chamber occupied by said cap when said second valve is open, a port opening into the smaller diameter part of said chamber between the larger diameter part and the bevelled head of said displaceable member and a second port opening into the large diameter part of said chamber occupied by said cap, and means acting on the outer bottom surface of said cap to govern the operation of the distributor.

References Cited in the file of this patent UNITED STATES PATENTS 721,499 Brennan Feb. 24, 1903 962,257 Rockwell June 21, 1910 1,314,153 Schneider Aug. 26, 1919 1,566,111 Miller Dec. 15, 1925 1,825,611 Bangerter Sept. 29, 1931 2,167,328 Beggs July 25, 1939 2,276,418 Rockwell Mar. 17, 1942 2,310,100 Losey Feb. 2, 1943 2,331,800 Rockwell Oct. 12, 1943 2,418,129 Larson Apr. 1, 1947 2,420,313 Hall May 13, 1947 2,440,687 Ingoldby May 4, 1948 2,472,694 Chouings June 7, 1949

Images