Abstract: A stress and torque reducing tool particularly useful in production of petroleum fluids from oil wells employing a reciprocating pump located within the well bore in the reservoir which is operated by means of sucker rods attached to a surface walking beam pump operating unit. The tool is deployed intermediate the sucker rod string and the plunger rod of the downhole reciprocating pump and provides a means for hydraulically dissipating shock forces encountered in the operation of the subsurface reciprocating pump occurring from fluid pound, gas pound and/or deliberately bottoming the plunger rod to avoid gas lock.

Abstract: A door closer wherein a housing defines a fluid-containing space and rotatably supports a shaft which is articulately connected with a pivotable door panel. A piston in the housing divides the space into a chamber and a compartment and has a toothed rack which mates with a pinion on the shaft so that the piston moves in the housing in response to rotation of the shaft as a result of pivoting of the door panel and vice versa. One or more springs in the chamber bias the piston in a direction to pivot the door panel toward closed position. A channel in the housing establishes communication between the chamber and the compartment during an initial stage of movement of the door panel from closed position at which time the piston moves in a direction to reduce the volume of the chamber.

Abstract: The damper assembly has improved valve means that includes at least one annular movable valve member of the voice-coil type. Such valve member is formed at least in part of composite material that increases the strength and stiffness of the member, while reducing its coefficient of thermal expansion and its weight. In a preferred embodiment of the invention, the assembly includes two movable annular valve members which are driven in unison with each other such that when one occupies a flow-permitting position the other occupies a flow-inhibiting position. Check valves utilized in the assembly preferably are of a resilient split-ring type.

Abstract: A hydraulic device is provided for controlling the rate of relative movement of first and second members between predetermined first and second stations. The device includes a housing connected to the first member and provided with a first cavity for hydraulic fluid and a second cavity for hydraulic fluid segregated from the first cavity. The first cavity has adjacent first and second segments with the second segment having a greater cross-sectional area. An orifice is disposed adjacent an end portion of the first cavity first segment which is remote from the second segment and interconnects the cavities. A valve is remote from the orifice and permits restricted hydraulic fluid flow from the first cavity to the second cavity and substantially unrestricted hydraulic flow from the second cavity to the first cavity. The direction of flow through the valve depends upon the direction of movement of a piston mounted for reciprocatory movement within the first cavity.

Abstract: A cushioning mechanism in a pneumatic cylinder utilizing a supplied air pressure, and a method of cushioning a piston in the pneumatic cylinder. Cushioning chambers are provided at opposite ends of a cylinder body of the pneumatic cylinder. Respective differential pressure valves and relief valves are provided between each of the cushioning chambers and an air supply. A cushioning member is disposed between each cushioning chamber and a cylinder bore. Air supplied under pressure from the air supply is stored in one of the cushioning chambers. When the piston is displaced to push the cushioning member, the air in the cushioning chamber is compressed to cushion the piston. As the cushioning member is moved a prescribed interval, the cushioning chamber is vented to atmosphere.

Abstract: A suspension damper has a piston 20 slidable in a cylinder 10 containing fluid. A compressible gas space 45 is provided in one end of the cylinder. To permit piston movement valve controlled passages 54 provide differential resistance in opposite directions of movement and an enlongated slot 51 provides a passage without valve control and the cross section of the slot 51 is selected to vary along its length to provide variable rate damping.

Abstract: An air pressure shock absorber for smoothly stopping a moving object reciprocated by a rod in an air pressure cylinder. The shock absorber absorbs and reduces the internal pressure of a chamber in the cylinder to smoothly stop the moving object by the communication of air compressed in the chamber to the atmosphere through a bypass passage formed in a cylinder wall. The air pressure is released to the atmosphere after the piston has moved through a predetermined stroke.

Abstract: An air pressure shock absorber for smoothly stopping a moving object reciprocated by a rod in an air pressure cylinder. The shock absorber absorbs and reduces the internal pressure of a chamber in the cylinder to smoothly stop the moving object by the communication of air compressed in the chamber to the atmosphere through a bypass passage formed in a cylinder wall. The air pressure is released to the atmosphere after the piston has moved through a predetermined stroke.

Abstract: A piston and cylinder motion dampening device having spiral groove metering, an orificed two-way pressure relief valve or a screw-on spring or an over-extension limiting seal retainer.A push-together method of assembling a piston and cylinder motion dampening device.A motion dampening device with a baffle chamber.

Abstract: The invention relates to an air and oil suspension device notably for motor vehicles adapted to act both as a shock absorber and as a pneumatic spring. It comprises means for compensating the expansion of the fluids contained therein in case of temperature increment. In a cylinder divided into two chambers one containing a gas and the other a hydraulic fluid is slidably mounted another hollow cylinder closed at both ends and containing essentially a hydraulic fluid and a reduced volume of gas under pressure. This second cylinder has an integral external piston-forming flange provided with opposite non-return valves permitting the passage in either direction of the hydraulic fluid which is thus caused to undergo a substantial loss of pressure, and at least one opening through the wall of said second cylinder under said flange so that the pressures can balance each other on either side of the wall of said second cylinder.

Abstract: A shock absorber is provided for automotive vehicles in which the damping force is dependent upon the position of the piston in a cylinder and therefore dependent upon the load. The damping forces in both directions of movement of the piston in a cylinder are higher in a more compressed portion than in a more expanded position of the shock absorber. The damping action for different portions of the stroke can be adjusted readily from the outside and independently for both directions of movement.