US2899976A - Release relief valve - Google Patents

Description

C. A. ELLIS E LLIS ATTNE E Aug. 18, 1959 RELEASE RELIEF VALVE Original Filed Jan.

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United States Patent "P RELEASE RELIEF VALVE Charles A. Ellis, Hamden, Conn., "assignor to American Optical Company, Southbridge, Mass., a voluntary association of Massachusetts Original application January 12, 1949, Serial No. 70,499, now Patent No. 2,711,632, dated January 28, 1955.

Divided and this application January 7, 1955, Serial 1 2 Claims. (Cl. IS7-599.2)

so as to insure safe operation of said systems without damage to mechanisms operated thereby in the event of failure of said mechanisms to function properly, together with metering means for controlling the rate of ow of a iluid through said valve.

A further object of the invention is to provide a releaserelief valve of the above character for use in hydraulic systems which is relatively inexpensive, comparatively simple in its construction and eicient in its operation.

Other objects and advantages of the invention will become apparent from the following description taken in connection With the accompanying drawings, in which:

Fig. l is a longitudinal cross-sectional view of the device of the invention and of a lift mechanism in operatively connected relation with said device.

Referring to the drawings wherein like characters of reference designate like parts throughout the several views, the invention is embodied in a hydraulic release-relief valve 10 mounted on a base 25 having a vertically disposed hydraulic lift cylinder 23 thereon. While other hydraulic mechanisms can be operated by the device of the invention, the lift cylinder 23 will be described herein for purposes of illustrating the invention.

A vertically disposed tubular support 22 is placed over the hydraulic lift cylinder 23 and its upper end is adapted to carry articles to be lifted by the cylinder 23.

The base 25 has a partially threaded opening 33 formed in its upper surface in which is threaded the lower end of an inner tubular member 34 (Fig. 4) and has a cap 35 threadedly mounted over its upper end, the cap 35 being of larger diameter than the tubular member 34 and formed with a peripheral shoulder 35a` against which the upper end of the outer hydraulic lift cylinder 23 is adapted to abut, with the lower end of the cylinder 23 being disposed within a circular ring-like boss 36 formed on the upper surface of the supporting disc and encircling the opening 33 therein. Thus, there is formed an inner chamber 37 within the tubular member 34 and a reservoir 38 externally of the member 34 but within the cylinder 23, with oil seals 39 provided adjacent the areas of connection between the parts of the device to prevent leakage of oil or other fluid from the chamber 37 or reservoir 38. The reservoir can be lled through a vertical opening 35a provided through the cap 35, which opening is sealed by a threaded plug 35b.

A piston 40 is mounted for vertical movement within the inner chamber 37 and has a rod 41 extending therethrough, with a portion of the rod 41 projecting beneath the piston 40, the portion of the rod 41 inside the piston Patented Aug. 18, 1959 ICC 40 being reduced in size to form a shoulder 42 against which the upper surface of the piston rests, with means such as a castellated nut and cotter pin arrangement 43 located over the lower end of the rod 41 to retain the piston 40 in Iplace. The upper portion of the rod 41 is of a length to extend upwardly through an opening in the cap member 35 and has a depression 44 formed in its upper end in which is seated a ball member 45. A hub 46 provided with a hollow 48 therein is formed on the under side of a disc 47 and is mounted over the upper end of the rod 41 with the bottom of the hollow 48 resting on the ball 45. The disc 47 has a resilient disc 49 of rubber or other resilient material secured to its upper surface which serves to resiliently support the tubular support 22 which is concentrically located with clearance about the cylinder 23 and vertically movable over it. The disc 49 serves to mechanically isolate the support 22 so that no vibration will be transmitted to an article being lifted by the support 22 from the operative units within the lift cylinder. Oil seal-s 50 are provided in the piston 40 and cap member 35 for preventing leakage of fluid, similarly to the seals 39 and a series of openings 34a are provided adjacent the upper end of the member 34 to permit escape of any fluid which might manage to find its way into the chamber 37 above the piston 40.

The valve 10 of the invention embodies a cylindrical housing 69 mounted vertically on the base 25 adjacent the lifting cylinder 23 and secured thereto as by bolts 70. The housing 69 is closed at its upper end and is disposed with its lower end over an opening 71 leading to a high pressure conduit 59 in the base 25 which communicates with the chamber 37 of the lifting cylinder 23. The opening 71 is threaded for reception of a. plug 72 which is screwed therein and which is provided with a central vertical bore 73 therethrough, the bore having a beveled upper edge indicated by the numeral 74.

A vertically extending tubular member 75 is provided with a lower end portion 76 of a size and shape to t within the bore 73 in the plug 72 and having a beveled portion 74 shaped to rest evenly upon the beveled edge 74a of the plug bore 73 as a valve seat. The tubular member 75 has a high pressure chamber 77 therein into which fluid under high pressure from conduit 59 is permitted to pass through bores 73 and 71. The housing 69 is preferably formed as separate upper and lower sections joined as at 78 so that the adjacent abutting portions may be threaded internally for reception of a block 79 having a vertical bore 80 therein.

A plug 81 is threaded into the upper end of the tubular member 75 and has a vertical bore 82 therein, concentric with and of smaller diameter than the upper portion of the chamber 77. The chamber 77 has a coiled spring 83 disposed therein for retention of a ball plug member 84 over the lower end of the bore 82 in the plug 81, the lower end of the spring 83 being adapted to rest upon shoulder 84a formed by a bore 84h communicating with the lower end of the chamber 77, which bore 8417 also communicates with the bore 73. Thus, fluid will be permitted to enter the chamber 77 from conduit 59 through bores 71, 73 and 84d but will be prevented from leaving by the ball 84 which is held over the end of the bore 82 by the spring 83. A coil spring 85 encircles the tubular member 75 and has its upper end disposed in a groove 86 formed in the lower surface of the block 79, its lower end resting upon the shoulder formed by an enlarged portion 87 of the tubular member 75. Thus, the tubular member 75 is continually urged downward by the spring to provide a seal between the adjacent conical surfaces 74 and 74a formed on the end portions 76 thereof and the opening 73 in the plug 72.

In the event that an excessive uid pressure is built up in the high pressure conduit S9 and the extent of the pressure is such as to overcome the tension of the spring 85, the tubular member will be forced upwardly within the block 79. This will draw the lower end portion 76 of the tubular member upwardly, providing a space between the conical surfaces 74 and 74a, which will permit the uid to pass from the high pressure chamber 77 into a low pressure chamber 88 formed by the walls of the housing 69, thus relieving the pressure within the chamber 37 of the lift cylinder and the chamber 77 of the valve 10. 'Ihe uid then passes through one or more openings 89 provided in the base 25 which communicate with a conduit 90, one end of which opens into the reservoir 38 within the lift cylinder 23. Thus, the uid can flow tothe reservoir 38 directly from the low pressure chamber 88.

Conventional oil seals 93 are provided within the housing 69 at various points for preventing leakage of the hydraulic uid at these points.

The valve 10 further includes a metering arrangement for lowering the lift cylinder from a raised position at a controlled rate of speed.

The metering arrangement embodies a rod 98 extending vertically through an opening in the top of the housing 69. Which is adapted to be mounted for vertical movement in the housing 69. The lower end of the rod 98 is positioned in a vertical opening in the upper end of the block 79 and has a collar 99 fixedly secured thereto as by a pin 100. The collar 99 having a flange 101 formed integral therewith, is adapted to rest against the under surface of the top of the housing 69. A coiled spring 102 is positioned about the rod 98 with its upper end resting against the flange 101 of the collar 99 and with its lower end abutting the block 79. Thus, the spring 102 will serve to maintain the rod 98 in position as illustrated in the drawing.

The lower end of the rod 98 is provided with a depression 103 of a size and shape for reception of the upper end of a vertically disposed valve operating member 104. The member 104 is of such length as to be spaced slightly away from the bottom of the recess 103 at its upper end to allow a slightly play between the parts of the device, and has its lower portion extending through the bore 82 in the plug 81 carried by the upper end of the tubular member 75, with its lower end resting against the ball 84 sealing the end of the bore 82. The lower end of the rod 104 is of a diametrical size substantially that of the bore 82 but tapers upwardly to a thin portion approximately midway thereof. Thus, by depressing the rod 98, the bottom of the recess 103 in the rod 98 will engage the upper end of the member 104 and will force it downwardly. This downward movement of the member 104 will also push the ball 84 downwardly against the tension of the spring 83 and, due to the taper of the member 104, fluid from the high pressure chamber 77 will ow into the bore 82 and from there it will proceed through a series of openings 105 in the plug 81 into the low pressure chamber 88, and from there into the reservoir 38 of the lift cylinder 23 through conduit 90.

It will be understood that upon relief of the high pressure within the chamber 77, this relief will also be felt by the fluid in the lifting device chamber 37. Thus, the the piston will be allowed to descend in accordance with the amount of uid permitted to leave the chamber 37. It will also be understood that the speed at which the chair is permitted to be lowered may be controlled by the operator of the rod 98, since he can control the distance which the valve operating member 104 will be depressed and consequently control the amount of uid permitted to escape from the chamber 77. Due to the fact that the member 104 is provided with a tapered portion, it is obvious that if the member 104 is urged downwardly to a considerable extent a considerable amount of the uid will be permitted to pass into the bore 82, while if the member 104 is moved only a slight distance downwardly, the amount of fluid passing into the bore 82 will be small.

In the event that the lift cylinder is lowered fast it is possible that the conduit will be unable to accommodate the entire amount of fluid permitted to escape at once from the high pressure chamber 77. Therefore, the block 79 is provided with a series of vertical bores 106 therethrough so that the fluid can also temporarily pass upwardly into the space formed in the upper portion of the housing 69 above the block 79.

The invention provides an improved release-relief valve as safety means for preventing damage to hydraulic systems in the event that excessive or damaging fluid pressures occur in said systems and also provides metering means under the control of an operator for controlling the extent of downward movement of a lift cylinder or the like and the speed at which the cylinder is lowered.

It is to be understood that the mechanism described hereinabove may be used with articles other than lift cylinders and is adaptable to various types of hydraulic systems.

While the novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the formation and details of the device illustrated, and in its operation, may be made by those skilled in the art without departing from the spirit of the invention.

Having described my invention, I claim:

1. A hydraulic release-relief valve comprising a solid outer wall casing having a centrally disposed uid inlet port in the base thereof and at least one iluid outlet port also in said base spaced from said inlet port, a tubular member dividing the interior of said casing into a pair of pressure chambers, said tubular member resting on the base of said casing when in normally closed position and having a central bore therein forming one of said pressure chambers, said central bore being in communication with said inlet port, said outlet port communicating with the other of said chambers, the central bore of said tubular member having an elongated upper section of reduced cross-sectional size, a longitudinally adjustable gate means disposed in said upper section, said gate means embodying an enlarged closure portion within said bore of a cross-sectional size greater than that of said upper section for normally closing the communication between said upper section and the remaining portion of said central bore and an elongated gradually tapering conical shank portion extending substantially throughout the length of said upper elongated reduced section of the central bore, said conical shank portion of the gate means having its end of greatest cross-sectional area substantially equal to the cross-sectional area of the elongated reduced upper section of said central bore and being in connected relation with said enlarged closure portion thereof, said tubular member having transversely disposed apertures extending between said upper section of the central bore therein and said other of the chambers, operable means for adjusting said gate means longitudinally in the upper reduced section of said central bore to open and close communication between the chambers in said casing whereby said gradually tapering conical shank portion will function to meter a ow of fluid through said communication in accordance with the extent to which said gate means is adjusted in said upper section of said central bore in the tubular member, said tubular member being adapted for movement toward and away from the base of said casing, and spring means normally urging said tubular member to remain at rest on said base, said spring means being under such tension that when a fluid in the tubular member exceeds a maximum pressure the said pressure, in excess of said maximum, acting on said tubular member will overcome the tension of said spring means and lift the tubular member of said base to permit a flow of said fluid into said other chamber having an outlet port to reduce said pressure and allow the tubular member to return to its normal closed position.

2. A release-relief valve device for a hydraulic system comprising a solid outer wall casing set on a base and having a centrally disposed high pressure lluid inlet port in the base, a ltubular member of smaller size than the interior of said casing located therein and dividing said casing into a pair of pressure chambers, one of said pressure chambers being `the central rbore of said tubular member and the other of said pressure chambers being the space between said tubular member and said outer wall casing, said 'tubular member resting on said base with its central ibore communicating with said high pressure inlet port when in its normal closed position, said casing having a portion projecting into the interior thereof and shaped to provide a slideway for receiving the upper end part of the tubular member, spring means surrounding the tubular member and resting on outwardly projecting means carried by the tubular member adjacent its lower end, the upper end of said spring means pressing against said projecting portion of the casing under compression, the ends of said central bore of the tubular member being of smaller section than the main portion of said bore, said tubular member having at least one transverse opening in its upper end communicating with said upper portion of the bore of reduced section and the space between said tubular portion and the casing, said casing further having a low pressure outlet port communicating with said space, gate means located in the upper end of the main portion of the bore of said tubular member, said gate means being of a size greater than the reduced section of said upper portion of said bore and operable to open and close communication between the main and upper por-tions of the bore, spring means having one end resting on the lower edge of the main portion of the bore and compressing against said gate means to maintain it normally closed, elongated conically shaped metering means extending substantially throughout Ithe length of the upper portion of said bore with its greatest area of cross-section adjoining said gate means and of a diameter substantially equal to the diameter of said upper portion of said bore, manipulatable means operatively connected with said metering and gate means for depressing said metering and gate means by overcoming the tension of the spring means urging the gate means to remain closed whereby uid may be permitted to ow from the main port-ion of the bore of the tubular member, through said transverse opening in said tubular member at controlled rates and in controlled amounts in accordance with the `extent to which said metering and gate means are depressed, the spring means surrounding the tubular member having 4tension suflcient to cause said tubular member to remain at rest on said base against fluid pressure up to a predetermined value, whereby, pressure in excess of said predetermined value will raise the tubular member, against said spring tension, oil the base to permit a ilow of fluid from said high pressure inlet port into the space between the casing and tubular member and through the low pressure outlet port of an amount suicient to allow the tension of the spring to return the tubular member to its normal closed position to automatically maintain a substantially constant predetermined high pressure in said tubular member while said gate means 'is closed.

References Cited in the file of this patent UNITED STATES PATENTS 367,563 Vielhaber Aug. 2, 1887 433,543 Schreidt Aug. 5, 1890 1,326,124 Vischer Dec. 23, 1919 1,688,092 Smith Oct. 16, 1928 2,565,050 Smith Aug. 21, 1951 2,591,562 Levcll Apr. 1, 1952 2,621,631 Dowty Dec. 16, 1952 2,711,632 Ellis June 28, 1955 FOREIGN PATENTS 436,431 Great Britain Oct. 10, 1935

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