US3405601A - Single rotary valve for hydraulic fluid and air - Google Patents

Oct. i5, i968 1. E. CLARKE 3,405,601

SINGLE ROTARY VALVE FOR HYDRAULIC FLUID AND AIR Filed March 23, 1966 (gli Vl.

Y' @55e al' e l; Z BY yg www, @OMIM United States Patent O 3,405,601 SINGLE ROTARY VALVE FOR HYDRAULIC FLUID AND AIR Jesse E. Clarke, Hinsdale, lll., assigner to Autoquip Corporation, Chicago, Ill., a corporation of Illinois Filed Mar. 23, 1966, Ser. No. 536,788 7 Claims. (Cl. 91-4) ABSTRACT OF THE DISCLOSURE A unit-ary two-part control valve is provided for an air-hydraulic system for operating a hydraulic cylinder. The valve comprises a cylindrical valve rotor in a valve body. The valve rotor is biased .to an intermediate position and is movable 90 degrees in either direction from the intermediate position to two end positions respectively. At one position along the axis of the rotor there is a hydraulic fluid passage diametrically therethrough. At the same longitudinal position the valve body has diametrically opposed ports, one port being adapted to be connected to the hydraulic cylinder and the other port adapted to be connected to the hydraulic reservoir below the level of the hydraulic fluid therein. At one end of the rotor an air passage extends from the end of the rotor into the interior of the rotor and then radially through the side of the rotor at a second position along the longitudinal axis thereof. At said second position the valve body has two diametrically opposed ports, one being the exhaust port and the second being adapted to be connected to the source of compressed air. At said end of the rotor, the valve body has an air port adapted to be connected to the hydraulic reservoir above the level of the liquid therein. Extending from the radial end of the air passage in the rotor is a small bleed passage about the periphery of the rotor which, when the rotor is in the intermediate position, communicates with the exhaust port. With the rotor in the intermediate position'the communication between the cylinder port and reservoir hydraulic port is shut off as is communication between the compressed air port and the air passage in the rotor. When the rotor is moved to one end position the cylinder and the hydraulic reservoir ports are in communication and the -air passage of the rotor is in communication with the compressed air port. At the other end position of the rotor the cylinder and the hydraulic reservoir ports are in communication and the air passage of the rotor communicates with the exhaust port.

Background of the invention One well-known form of hydraulic elevating device uses a single hand-operated valve for controlling the ow of compressed air into and out of a hydraulic uid reservoir. Movement of the valve to one position permits compressed air to enter and pressurize the hydraulic fluid within the reservoir. The pressurized liuid then flows through an open line to a hydraulic cylinder and raises a platform or the like. To lower the platform the hand operated valve is pivoted to a different position which opens the reservoir to the atmosphere and permits the compressed air therein to exhaust. The platform then lowers accordingly. This type of system is frequently used in automotive garages because of its simplicity and because these garages normally already have a source of compressed air for performing other services such .as intlating tires, greasing, etc. A distinct disadvantage of such a system results from the compressible nature of air which gives the lift a genice erally spongy characteristic making it ditiicult to accurately position and lock the lift at a height intermediate of its end positions.

Where more accurate control of the vertical positioning lift is required, a second control valve is frequently interposed in the hydraulic uid line which extends between the reservoir and the hydraulic cylinder. After pressurizing Ithe reservoir by means of the first or compressed air valve, the second valve is opened to control the flow of uid into the hydraulic cylinder, thus substantially eliminating the spongy effect of the compressed air. Of course, if the lift operator overshoots the desired platform height, he must depressurize the reservoir with the lirst valve in order to permit drainage from the cylinder to the reservoir by means of the second valve. For this reason, many experienced lift operators save time in accurately controlling the vertical positioning of the platform by endeavoring to simultaneously manipulate both valves, each with a different hand. Until the lift operator is thoroughly experienced in the use of this two-valve system, he is likely to waste time adjusting the platform to the desired height, and more importantly, the confusion resulting from the novices attempt to use two handles simultaneously could cause injury to objects or people in the path of movement of the platform.

It is therefore a general object of this invention to provide a single control for a pneumatically powered hydraulic lift system which both controls the flow of compressed air into and out of the hydraulic iiuid reservoir as well as accurately metering the ow of hydraulic fluid into or out of the lift cylinder.

An advantage and feature of the invention resides in the provision of means by which the reservoir is inherently depressurized after being elevated, thereby eliminating the task of depressurizing the reservoir before lowering the platform.

Other objects, advantages `and features will become apparent upon a reading of the following description when taken in conjunction with the following drawings, wherein:

FIGURE 1 is a schematic diagram of a sample form of hydraulic elevating system including a separated land broken away View of the valve assembly which incorporates the principles of one preferred form of the present invention;

FIGURE 2 is a cross-sectional view of the valve assembly shown in FIGURE 1; and

Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

It can thus be seen that the control valve assembly permits single handle control of a hydraulic lift platform, and also eliminates the necessity of exhausting air pressure from the reservoir prior to lowering the platform.

I claim:

1. In a gas-liquid hydraulic system for use with a source of compressed gas and comprising a uid reservoir having a gas connection above the fiuid level therein and a liquid connection below the uid level therein, a fiuid operated cylinder normally urged to the retracted position, a valve means connected to the cylinder, the source, the gas and fluid connections and to a gas exhaust to control the flow of gas between the source, the exhaust and the reservoir and to control the ow of liquid between the reservoir and the cylinder, the improvement comprising: said valve means being a unitary two-part valve including a valve body with a valve member movable therein between three positions to wit, a first end position, an intermediate position and a second end position, one part of said valve means comprising a first portion of said member defining a first fiuid passage and a first portion of the body defining a cylinder port and a liquid connected reservoir port, said first fluid passage communicating with both ports when the member is in the first and second positions and blocking communication between the ports when the member is in the intermediate position, the second part of the valve means comprising a second portion of said member defining a second fluid passage, a second portion of the body defining a gas source port, an exhaust port and a gas connected reservoir port, said second fluid passage communicating with said source port and with said gas connected reservoir port when said member is in the first position and with said exhaust and said gas connected reservoir port when the member is in' the second position, whereby when said member is in the first position gas will be fed from said source to said reservoir and liquid will flow from the reservoir to the cylinder and when said member is in the second position gas will ow from the reservoir to exhaust and liquid will flow from the cylinder to the reservoir.

2. In a system as set forth in claim 1, wherein said second portion of said member defines a bleed passage of smaller gas transmitting capacity than said second fiuid passage, said bleed passage being in communication with said gas connected reservoir port and with the exhaust port when the member is in the intermediate position.

3. In a system as set forth in claim 2, including resilient means connected to said member to resiliently urge said member to said intermediate position.

5. In a system as set forth in claim 4, wherein said member is cylindrical and said bleed passage is a groove at the exterior of the member.

6. In a system as set forth in claim 1, wherein said valve member is a solid of revolution about an axis, said first fiuid passage extending radially through said member, said second iiuid passage extending from the interior of the member to one side and from the interior of the member to the adjacent end of the member, said body defining an interior opening of substantially the same configuration as the exterior of the member to fit closely thereabout, said cylinder port and said liquid connected reservoir port being diametrically opposite each other in the body and in the same position along the axis as the ends of said first passage, said gas source port and said exhaust port being diametrically opposite each other in the body and in the same position along the axis as the side end of the second fiuid passage, said gas connected reservoir port being in the end of the body corresponding to said adjacent end of the member and in communication with the second fluid passage at said adjacent end; and including O-ring seals between the body and the member at each side of said two passages.

7. In a system as set forth in claim 6, including resilient means connected to said member to resiliently urge said member to said intermediate position.

(References on following page) 7 8 References Cited 3,217,744 11/ 1965 Y Racicot 137-625.23 Howard 5/1931 Hansen 91-4 4/19'54 Aikman 91-4 5 MARTIN P. SCHWADRQN,l Plzmary Examiner.. 12/ 1955 Bonham 137-625.23 B. L. ADAMS, Assistant Examiner.

4/1965 Konkle 91-4