Abstract: A telescopic prop for use in mine workings extends and retracts over three stages. The prop has an outer main base member 1 with respective first, second and third concentric inner members 2, 3, 4 disposed one within another. The first inner member has a piston 6 in which is arranged a non-return valve 23 which normally shuts off communication between a working chamber 20 associated with the first and base members and the working chambers 22, 27, 29 pertaining to the other members. A plunger 24 is provided to open the non-return valve when the first inner member is nearly fully retracted inside the base member so that after retraction of this stage the other stages can be retracted. The second or intermediate member also employs a piston 9 which is connected via a rod 13 with an auxiliary piston 15 disposed in a working chamber associated with the uppermost third member.

Abstract: A pressure actuator is provided for a valve having a housing and an actuating stem, wherein an annular housing is attachable at one end of the valve housing and a cylindrical piston element is concentrically fixedly mounted to the other end of the annular housing. A cup-shaped cylinder is provided to cooperate in sliding and sealing relationship with the exterior of the piston. The cylinder defines an annular space between its exterior surface and the interior bore of the annular housing and spring elements are mounted in the annular space. If desired, an indicating stem passes through a bore in the fixed piston element and is interiorly engaged with the movable cylinder element, thus providing an indicating actuator wherein the total length of the actuator is not substantially in excess of twice the stroke of the actuator.

Abstract: Valves are located at opposite ends of a cylinder and are automatically moved toward closed positions at a controlled rate as a piston approaches the ends of the cylinder. Upon being moved toward its closed position, each valve restricts the flow of exhaust air from the respective end of the cylinder and causes the piston to decelerate so as to cushion the piston as it comes to a stop.

Abstract: A fluid pressurizing device 10 having a master cylinder 12 with a cylindrical projection 52 that extends through the housing of a brake booster 14. The housing of the brake booster 14 has a front shell 56 located on a shoulder 54 of the cylindrical projection 52 and a rear shell 140 located against a shoulder 150. A nut carried by the cylindrical projection 52 engages the rear shell 140 to compress a bead 111 of a diaphragm 110 against a shoulder 57 on the front shell 56. A sleeve 80 connected to a hub member 70 retains a bead 108 of diaphragm 110 and bead 90 of a diaphragm 92 connected to the cylindrical projection 52. In response to an input force, a valve assembly 136 controls the development of a pressure differential across the diaphragms 92 and 110. The pressure differential acts on and moves the diaphragms 92 and 110 toward the first shell 56.

Abstract: A leak-detecting hydraulic system is disclosed for operation of a fluid actuator associated with a front-end loader, a backhoe, or a like implement on a material handling device. Notably, the system includes a leak-detection circuit which normally acts to prevent movement of the implement associated with the actuator by gravity in the event of a failure in one of the hydraulic fluid lines operatively connected with the actuator. Additionally, the system preferably includes a selectively operable float valve which permits fluid flow which bypasses the leak-detection circuit, thus desirably permitting operation of the implement associated with the actuator in a "floating" mode.

Abstract: A device for accommodating bending a cable or the like by remote control is proposed. It has a cylinder with a piston rod, and two holders coupled to the cylinder and the piston rod at each end thereof. The holders through which a cable runs are bent by remote control by relative movement between the cylinder and the piston rod.

Abstract: A reciprocable plunger fuel injection pump includes a plunger reciprocable in a bore. The plunger is urged outwardly by a spring which engages a spring abutment. The abutment carries a thrust member which engages the end of the plunger and in use is engaged by an actuating member such as a cam. The thrust member is held within a recess in the abutment by a resilient member. The thickness of the thrust member can be selected during assembly of the pump to the associated engine.

Abstract: A power assistance device has a double acting piston and cylinder whose piston rod is connected to an output. Compressed air is passed via a pair of air pressure regulators to opposite sides of the piston. Each regulator has a regulator spring, and the regulators are housed in a body which is moved upon manual effort being applied to an input to cause the springs to differentially bias so decreasing pressure on one side of the piston and increasing pressure on its opposite side, creating a pressure differential across the piston causing it to move with its piston rod to apply a magnified load to the output which is proportional to the manual effort applied to the input. The regulators could be set so that in a neutral position of the power assistance device, zero pressures exist on opposite sides of the piston. In an alternative arrangement a pair of single acting piston and cylinder devices could be used.

Abstract: A control-circuit throttle valve assembly coupled to and regulating a hoisting unit correcting element or final control element of a tractor via a mechanical coupling including a throttle housing, a flow restrictor throttling body shiftably mounted in the throttle housing, the throttling body having a guiding edge portion, a control conduit with a circular cross-section communicating with the throttle housing, the control conduit including a pass-through area, and a run-off conduit communicating with the throttle housing, the guiding edge portion at least partially closing off communication between the control circuit and the throttle housing through the pass-through area upon shifting of the throttling body within the throttle housing such that the pass-through area is throttled as a linear function during operation of the hoisting unit.

Abstract: The invention relates to an oil well jack having a walking beam mounted on a frame for motion in a vertical plane; and a plurality of hydraulic actuators connected to move the walking beam. The amplitude of movement of the beam as well as the frequency of the stroke are adjustable through regulation and control of the hydraulic system.

Abstract: In a machine of the kind in which an operative member under the actuation of driving means is reciprocatable relative to a guide member in order to exert forces in a predetermined direction on a workpiece, toothed and elongate roller bodies having their axes of rotation extending perpendicularly to said direction are interposed between the guide member and the operative member in order to prevent the latter from tilting. The teeth of each roller body mesh with the teeth of racks extending in said direction of movement of the operative member and being provided on both the guide member and the operative member in a manner to cause each roller body to transmit under torsional strain balancing forces in its axial direction. The roller bodies also have cylindrical surface portions being coaxial with and having the same diameter as the pitch circles of their teeth, said cylindrical portions being in rolling contact with rollways provided on both the operative member and the guide member.

Abstract: A shock absorbing device for a hydraulic cylinder including a shock absorbing hole formed in an end wall of cylinder, a passageway having a port opening in the shock absorbing hole at its inner peripheral surface and a shock absorbing member attached to the piston and aligned with the shock absorbing hole so that it enters the hole during shock absorbing stroke. During movement of the shock absorbing member, it throttles the flow of fluid in the hole to perform a first stage shock absorption, then throttles the flow of fluid through the port to perform a second stage shock absorption, and at last compresses the fluid in the bottom of the hole to perform a third stage shock absorption.

Abstract: A cylinder driven reciprocator uses a block and tackle output to broaden the mechanical range of the cylinder. The output force, speed, and travel distance depends upon the number of moveable pulleys between a fixed reference point and the output attachment on the cable.

Abstract: A hydraulically-operated breaking device of this invention uses a hydraulically-operated differential piston for driving an electric circuit switching unit, and making and breaking pilot valves for actuating the differential piston. In this device, a control valve operated by the action of the pilot valves includes two poppet valves, and drives an intermediate valve which drives the differential piston. Further, the control valve can perform a quick operation at breaking, and can accomplish a given operation even with use of impulse command signals to operate the pilot valves or even in case of a liquid pressure drop during the operation. Furthermore, the use of an auxiliary valve and an auxiliary switch provides the device with a simultaneous action preventive function, pumping action preventive function, and breaking operation preference function.

Abstract: A pump for pumping fluids which contain a high degree of suspended solid particles comprises a piston provided with a cylindrical sleeve of a hard ceramic material having a hardness of greater than nine on the Mho scale, preferably an aluminum oxide ceramic or a zirconium nitrate ceramic, and a cylinder provided with a cylindrical sleeve of like ceramic material.

Abstract: A pumping unit for wells which is hydraulically powered and adapted to replace or used in lieu of conventional pump jacks. The hydraulic system utilized with the hydraulically operated pumping unit includes an accumulator system which stores energy produced by gravity induced downward movement of the pump rod and other pump components during the down stroke and automatically utilizes this stored energy to assist in lifting the pump components and the column of production fluid thereby increasing the efficiency of the pumping unit.

Abstract: A tandem type brake power servo booster and toggle joint include a cylindrical member which has a first engaging portion for engaging a second engaging portion of a front power piston so that relative rotation between the cylindrical member and the front power piston can be prevented when a nut is tightened to secure the cylindrical member and the front power piston into position. In addition, a key member extends through a valve body and a hub of the cylindrical member to engage a valve plunger, and a surface of the key member which faces a push rod is spaced apart from the valve body to form a clearance between the valve body and the key member surface, thus providing the toggle joint with increased strength. In addition to the nut which serves as a stop, a second stop is formed on the hub so that the first and second stops integrally join the valve body and a center body of the cylindrical member with each other.

Abstract: This invention pertains to a hydraulic reciprocating device having a housing and a piston in the housing. The piston has a first and second surface, and a means for intermittently communicating the first surface of the piston with a hydraulic pressure source. Also provided is a means for continuously communicating the second surface of the piston with pressurized fluid such as pneumatic fluid. The piston moves in a first direction when the hydraulic pressure source communicates with the first surface of the piston and the piston moves in a second direction when the hydraulic pressure source does not communicate with the first surface of the piston.

Abstract: An activating apparatus or device, for example for a valve in a liquid conveying system operated by means of a vacuum. The activating apparatus comprises a normally latched or locked operating device which by means of a spring, or the like, is connected to a force accumulator. The force accumulator is moved by the influence of vacuum and thereby tightens the spring which, when a lock arm disengages from the operating device, is released so that the operating device is moved, and thereby opens the valve.

Abstract: A pressure-medium-driven linear driving arrangement comprises a slide-shaped driving unit supported on a feed rack with a sliding curve. The driving unit comprising step-by-step elements in the form of piston-cylinder systems, which are controlled by a pressure medium via a rotary slide valve to produce a relative motion between the driving unit and the feed rack. The step-by-step elements each have a pivoted lever joined on one hand to the piston of the step-by-step element and on the other hand, joined to the slide housing, constituting self-centering feeding link driving elements.