Abstract: A hydraulic damper according to the present invention includes a cylinder, working fluid disposed in the cylinder, a piston partitioning the cylinder into two fluid chambers and including passages therethrough for providing fluid communication between the two fluid chambers, and a damping force generation mechanism. The damping force generation mechanism includes a large diameter valve disc mounted adjacent the passages, a smaller diameter valve disc stacked against the large diameter valve disc, an inner pressure chamber formed adjacent and in fluid communication with the passages, and an outer pressure chamber formed adjacent and in fluid communication with the passages and formed radially outwardly of the inner pressure chamber. A partition wall is formed between the inner and outer pressure chambers and a passage is formed through the partition wall for communicating between the inner and outer pressure chambers.

Abstract: A hydraulic shock absorber includes a cylinder, a piston axially slidably fitted in the cylinder so as to divide the interior of the cylinder into a first cylinder chamber and a second cylinder chamber, and a damping force generating mechanism mounted on the piston for generating damping force by controlling the flow of the working fluid between the two chambers. The damping force generating mechanism comprises first and second passages and first and second recesses. The first passage is formed through the piston oblique to the axis of the piston and connects the first and second cylinder chambers. The first recess is formed in one end of the piston on the side of the outlet end of the first passage so as to include the outlet end of the first passage. The second passage is formed through the piston parallel to the axis of the piston, at a circumferential position differing from that of the first passage, and connects the first and second cylinder chambers.

Abstract: A hydraulic shock absorber comprising a cylinder, a partition member for partitioning the interior of the cylinder into two chambers and a damping force generating mechanism for regulating the oil flow through a communication passageway formed through the partition member and connecting the two chambers with each other. The damping force generating mechanism comprises a disk valve seated on a seat formed on the partition member and adapted to open in response to the oil pressure in the communication passageway; a damping force regulating chamber arranged on the side of the disk valve remote from the partition member; an oil passageway for connecting the damping force regulating chamber to the communication passageway; an orifice disposed in the oil passageway to restrict the area of the oil passageway for oil flow therethrough; and fulcrum member arranged in the damping force regulating chamber and in contact with the disk valve for providing a fulcrum for the disk valve to deflect.

Abstract: A hydraulic shock absorber is used, for example, in a vehicle, wherein the level of damping force is adjustable in accordance with the road surface conditions or the like during operation of the vehicle. The hydraulic shock absorber includes a piston attached to one end of a piston rod and slidably fitted in a cylinder, the piston dividing the interior of the cylinder into two cylinder chambers. A passage is provided in the piston, the passage communicating with each of the two cylinder chambers. A damping force generating valve is provided at the downstream side of the passage to generate damping force. A back-pressure chamber is formed at the side of the damping force generating valve which is remote from the piston to apply pressure to the valve. A bypass passage is formed in the piston rod to provide communication between the back-pressure chamber and the upstream cylinder chamber that is provided at the upstream side of the passage.

Abstract: A hydraulic damper of adjustable damping force type includes a cylinder containing hydraulic liquid therein, a piston working in the cylinder and partitioning the interior thereof into first and second liquid chambers, a piston rod secured to the piston and extending through the first liquid chamber to the outside of the cylinder, a valve mechanism mounted on the piston for generating damping force both in extension and contraction strokes of the damper, and an adjusting mechanism for adjusting the damping force.

Abstract: A vehicle height adjusting device including a hydraulic damper having a main body and a piston rod projecting upward from the main body, an air spring unit having a shell connected to the projecting end of the piston rod and a deformable resilient member with one end secured to the shell and the other end connected to the main body thereby defining an air chamber around the piston rod. The device comprises a sensor member secured to the shell and extending vertically in the air chamber, a detected member vertically displaceably mounted on the sensor member, first and second springs acting on opposite sides of the detected member, a retainer vertically displaceably mounted on the sensor member and receiving the lower end of the second spring, and a third spring acting between the retainer and the main body.

Abstract: A hydraulic damper of the adjustable damping force type includes a cylinder containing hydraulic liquid therein, a piston working in the cylinder and partitioning the interior thereof into two liquid chambers and having a damping force generating mechanism, a piston rod connected to the piston and extending through one of the liquid chambers to the outside of the cylinder, a coaxial bore formed in the piston rod, a liquid passage communicating the liquid chambers independently from the damping force generating mechanism and including at least a portion of the bore in the piston rod, an adjusting rod inserted into the coaxial bore and operated rotatably from the outside of the damper, and a rotary valve secured to the adjusting rod for selectively changing the effective passage area of the liquid passage.

Abstract: A hydraulic damper of adjustable damping force type includes a cylinder containing hydraulic liquid, a piston working in the cylinder and partitioning the interior thereof into two liquid chambers and having thereon a damping force generating mechanism, a piston rod connected to the piston and extending through one of the liquid chambers to the outside of the cylinder, a coaxial bore formed in the piston rod, a liquid passage communicating the two liquid chambers independently from the damping force generating mechanism and including at least a portion of the bore in the piston rod, an adjusting rod inserted into the coaxial bore and rotatable from the outside of the damper, and a rotary valve secured to the adjusting rod and having a plurality of circumferentially spaced and radially extending orifices for selectively changing the effective passage area of the liquid passage. A check valve on the inner circumference of the rotary valve rotates integrally therewith in the circumferential direction.

Abstract: A hydraulic damper includes a cylinder containing hydraulic liquid, a piston slidable in the cylinder and partitioning the interior of the cylinder into two liquid chambers, a passage formed through the piston to communicate the two liquid chambers, a piston rod connected to the piston and extending out of the cylinder, and a valve for controlling the liquid flow in the passage. The piston is axially displaceable relative to the piston rod by a limited amount, and the valve comprises an annular disc mounted on the piston rod and cooperating with one side surface of the piston when the piston abuts with the disc when the piston displaces in one direction and separating from the piston to form a clearance therebetween which acts as an inlet of the passage when the piston displaces in the opposite direction.

Abstract: A damping force generating mechanism in a hydraulic damper includes a housing containing therein oil and an oil chamber partitioning member such as a piston. The mechanism includes a communicating passage provided in the oil chamber partitioning member and defining an annular valve seat on one end thereof and an annular valve plate provided on one end of the communicating passage and being deflectable toward and away from the valve seat for permitting the oil to flow in the communicating passage in one direction. The plate valve consists of a plurality of mutually overlapping annular plates, and at least one of the annular plates is deflected in the direction separating from the valve seat by a projection member which also is one of the annular plates.

Abstract: A gas spring comprising a cylinder, a rod slidably extending from the cylinder, and a novel locking mechanism. The mechanism comprises first and second axially contiguous recesses in the circumference of the rod, a locking member normally located in the first recess and snappingly and rockingly movable between two recesses, and axially spaced first and second actuating members cooperating with the locking member. The first actuating member comprises an engaging portion and a releasing portion being circumferentially spaced therefrom. The releasing portion acts to displace the locking member to the second recess. The second actuating member comprises an engaging portion for locking the rod and also for displacing the locking member to the first recess, and axially and circumferentially inclined guide walls for circumferentially displacing the locking member thereby guiding the same between the releasing portion and engaging portions in response to the movement of the rod.

Abstract: An extensible strut such as a gas spring and having a cylinder, a rod guided by the cylinder and slidably extending through one end of the cylinder to the outside, and a locking mechanism for locking the rod at an extended position.