A shock absorber of the direct acting hydraulic type is disclosed as comprising a reciprocable piston having a piston body, the piston body being formed with first and second sets of spaced flow ports, the sets of flow ports being concentrically oriented with the first set being spaced radially inwardly from the second set; a first valve seat on one end of the piston body adjacent the first set of flow ports; a first valve member engageable with the first valve seat to block fluid flow through the first set of flow ports; first and second sequentially operable springs for resiliently urging the first valve member toward the first valve seat; second and third valve seats on the opposite end of the piston body and located radially inwardly and outwardly from the second set of flow ports; a second valve member in the form of a flat annular valve disc disposed adjacent the second and third valve seats and engageable therewith to block fluid flow through the second set of flow ports; the ends of the second set of flow ports confronting the second valve member terminating in enlarged size recesses, the area of which is in a predetermined ratio to the cross sectional area of the second set of flow ports.
RELATED APPLICATIONS
This application is a continuation of Ser. No. 668,915 filed Mar. 22, 1976, now abandoned, which is a continuation-in-part of Ser. No. 542,617 filed Jan. 20, 1975, now U.S. Pat. No. 3,945,474.
A hydraulic exerciser formed with a structure comprising a cylinder and an oil reservoir surrounding the cylinder and communicated therewith, a piston is slidably mounted in the cylinder, the upper end of the piston rod is protruded beyond a bearing which is supported on the upper end of the cylinder and the oil reservoir and provided with oil passages. There is a controlling mechanism provided with respect to the oil passages, which comprises a disc member has a sloped outer ring portion and an inner ring portion with a spiral contour; and a bushing member associated with the disc member and on which an oil hole is provided, with the turning of the bushing member relative to the disc member, the oil hole is covered by the spiral inner ring portion with different degrees and so that the opening thereof can be adjusted, the resistance of the oil when passing the oil hole and the oil passages thus can be varied.
A valve structure according to the present invention is used for a hydraulic buffer provided with a member for partitioning the interior of a cylinder into two liquid chambers and having a plurality of ports for affording communication between both liquid chambers. The valve structure includes a valve body formed annularly of a leaf spring for opening and closing the ports and secured to the member on an inner peripheral portion thereof, a spring for biasing the valve body toward the member and a spring seat disposed movably between the spring and the valve body and having an abutting portion projecting toward the valve body at a side contacting the valve body. The valve body can flex about an outer peripheral edge of the abutting portion and an outer peripheral edge of the fixed portion.
A hydraulic shock absorber utilizing variable fluid pressures to change the dampening characteristics of the shock absorbers, both during its compression stroke and its recoil stroke. A piston assembly of the shock absorber divides the damping fluid chamber of the shock absorber into a recoil chamber and a compression chamber. The piston assembly carries a recoil valve and a compression valve that control the flow of damping fluid across the piston assembly between the recoil and compression chambers. Pressure of a second fluid introduced into the piston assembly through a passage in the piston rod and biases the recoil and compression valves to closed positions. The pressure of the damping fluid in the compression chamber and in the recoil chamber bias the recoil and compression valves toward their open positions. The pressurized fluid passage in the piston rod is connected, outside the shock absorber, with a source of fluid whose pressure may be selectively varied.
The invention is directed to a shock absorber in which the structure of both the main valve and the pilot control valve is simplified, and makes their operation less vulnerable to malfunction because the number of parts moved relative to one another is reduced. This is achieved by functionally uniting the valve plate and pressure plate in an especially embodied novel valve plate, in the form of an annular shim with a fingerlike toothed contour of the inside circumference, which pierces a corresponding contour of an axial region of a stroke limiter, as a result of which a guidance of the valve plate quite close to the force introduction points by means of a spring or the openings to be closed takes place, thereby preventing unilateral opening of a valve plate. The relief piston is sealed off from the pilot control chamber by means of one gap seal and one sealing ring, so that the production tolerances can be greater and as a result an original-shape method without remachining is possible in manufacture.
A hydraulic shock absorber exhibiting a constant vibration damping force. The shock absorber is provided with a deep groove formed on an upper surface of a piston in a circle where piston ports formed through the piston lie and communicated with the piston ports. The groove has an outer peripheral wall in such a manner that an upper opening is upwardly enlarged.
