Abstract: A piston cylinder assembly includes a housing defining a housing cavity, a piston movably supported by the housing, and a spring return assembly connected between the housing and the piston. A fluid supplied to the housing cavity is operable to cause the piston to extend out of the housing and the spring return assembly is operable to cause the piston to retract into the housing. The spring return assembly includes a first spring member connected at one end to the housing and having an opposite end. The first spring member is operable to apply a first spring force. A second spring member is connected at one end to the piston and has an opposite end. The second spring member is operable to apply a second spring force. The opposite end of each of the first second spring members cooperate to apply the first and second spring forces in series.

Abstract: The invention relates to an energy-efficient apparatus driven by compressed air and equipped with a dual piston function for tensioning, or clamping, or centering, or punching, or welding, or clinching, for use in body construction in the automotive industry. The apparatus is driven by a pressurized fluid, in particular by compressed air. It is shown how a significant amount of operating costs can be saved while, at the same time, conserving the environment and consuming a low amount of pressurized fluid, in particular compressed air. In addition, the pivoting angle of a toggle joint assembly and thus of an apparatus connected thereto, for example, a tensioning arm of a toggle tensioning apparatus, can be continuously adjusted in both directions while, at the same time, adjusting a sampling device using sensors, for example, microswitches, or inductive switches, or pneumatic switches, or limit switches.

Abstract: An adjustable-length actuating element comprises an energy storing device. A casing and a piston rod, which is displaceable in the casing, are provided within the actuating element. A spindle drive is integrated in the energy storing device. A driving shaft is in rotary driving connection with the piston rod.

Abstract: A hydraulic drive (10) for the adjustment, feed and return movements of a tool head of a machine tool comprises a hydraulic motor (11) and an after-running adjustment valve (12). The reference value of the position is set and the actual value indicated by means of a threaded spindle (39) and spindle nut (37) in the form of a hollow shaft. One of these two elements can be driven by an electric motor (41) in order to set the reference value of the position. The other of these two elements can be driven in order to indicate the value of the actual position. A rotational and angular position indicator system (68, 74, 75 and 69, 77) produces an output which is a direct measure of the total number of revolutions executed by the preset reference value shaft and of the azimuthal position of the preset reference value shaft within each revolution. An electronic position sensor system (71, 78 and 71', 78'; 71") produces an output which is a measure of the contouring error S.

Abstract: A hydraulic actuator (1) with automatic wear take-up, is formed with a first piston (17) sliding in a blind bore (13), a second piston (33) in a bore made in the first piston, and an output rod (3) bearing on the second piston. A first chamber (27) is formed between the blind bore and the first piston and a second chamber (37) is formed between the bore and the second piston. A piece (19) having a shoulder (23) is fixed, on its side of smaller diameter, to an end (21) of the first piston confronting the first chamber, forming an annular space. The annular space contains an annular gasket (39) and stop (41), so as to divide the first chamber into two volumes (43, 45), one (45) connected to a pressure generator (7) and the other (43) communicating with the second chamber through a duct (47) made in the end of the first piston. The two volumes communicate with one another, at rest, via a passage provided between the gasket, the stop and the piece.

Abstract: A fluid pressure operated positioning apparatus has a cylinder (1), formed as an annular cylinder, with an outer cylinder wall (2) and an inner cylinder wall (3) coaxial with and spaced apart radially from the outer cylinder wall. In the annular cylinder, a piston arrangement including at least one ring piston (8) is slidably guided, its ring piston surrounding the inner cylinder wall and being connected to at least one elongated force transfer element (22) that is extended in a sealed manner out of the annular cylinder.

Abstract: A brake actuating mechanism includes a housing defining a cylinder and a tubular piston, slidingly sealed within the cylinder. A pull-rod passes through the piston and is provided at one end with member for connection to a brake linkage mechanism. The other end of pull-rod is provided with abutment member which engages one end of a guide spool, the other end of the guide spool engaging the end of the piston. A pivot member is provided between the guide spool and the piston to permit rocking of the guide spool and pull-rod relative to the piston. A lever mechanism may act on the guide spool to provide for mechanical actuation of the brake.

Abstract: A tire carcass transfer device (111) having a hollow housing (112) for receiving a tire carcass (160), a plurality of flexible cups (21) arranged in a circular band around the housing, vacuum means connected to the cups (21) and fluid powered actuators (10) for radial movement of the cups. The actuators (10) each have a return spring (24) therein to move piston (14) of the actuator (10) radially outwards by a predetermined amount on cessation of operation of the fluid powered actuator. Since all the pistons (14) are moved the same distance outwards by their respective springs (24), distortions to the carcass from its circular shape are minimized. An actuator (10) having a return spring (24) operating on a rod (15) operably connected to a piston (14) to return the actuator piston to a mid stroke position is also described.

Abstract: For use with a pumped well having a string of sucker rods connecting to a downhole pump, hydraulic pumping apparatus is disclosed. In the preferred and illustrated embodiment, a polished rod is surrounded by a selectively located sleeve. The sleeve locks to a piston in a hydraulic cylinder. The piston is forced upwardly. The length of stroke is adjusted. The location of the sleeve on the polished rod is likewise adjustable. This enables the device to be adjusted so that any length of sucker rods can be accommodated without requiring cutting sucker rods to achieve a particular length. Moreover, the length of stroke is adjustable to take into account the stroke of the pump and sucker rod elongation during operation.

Abstract: The invention pertains to vehicle brake actuators of the expansible motor type wherein the actuator includes a cylinder having a piston and piston rod assembly reciprocal therein, a helical spring biases the piston in a braking direction, and a pressurized medium, such as hydraulic fluid, forces the piston in a spring compressing direction. The unique features include a piston drawn from sheet metal wherein the piston rod is pressed thereinto, and the piston seals are retained in position by a wire ring having an interference fit with the piston. Additionally, novelty resides in the use of a retainer formed of wire or of stamped construction having protuberances defined thereon for retaining the cylinder end cap upon the cylinder in a manner to permit ease and safety of assembly, and uniform force distribution.

Abstract: In a combine harvester header, a modified hydraulic cylinder for controlling reel height includes a cylinder rod sub-assembly having a threaded portion permitting rotation of the cylinder rod to make adjustment of the cylinder rod effective length for fine or supplementary adjustment of the harvester reel relative to the platform cutterbar. A dual purpose member, pivotably captive on a rotatable nut portion of the cylinder rod sub-assembly, is swingable between an approximately horizontal position in which it serves as a wrench handle for rotatably adjusting the cylinder rod threaded portion and, downwards, into a safety stop position where it is engageable with the end of the body of the hydraulic cylinder to prevent inadvertent lowering of the reel from a fully raised position.

Abstract: Disclosed herein is a hydraulic jack comprising a cylinder and a piston rod assembly which is movable between a retracted position and an extended position relative to the cylinder. The jack also has mechanical locking means including a rotatable shaft and movable into engagement with the piston rod assembly in response to rotation of the shaft, thereby to lock the piston rod assembly in its extended position. The locking means reinforces the piston rod assembly in its extended position along substantially the entire length of the piston rod assembly.

Abstract: A stroke-adjusting drive mechanism in which the stroke of a reciprocating member, such as a piston, is adjustable for use in machines such as hydraulic presses and press brakes is disclosed. The apparatus includes a cylinder and piston with a piston rod member which projects outwardly from the cylinder. A restricting valve means is arranged between a chamber of the cylinder defined by the piston member and a hydraulic passage connected with a hydraulic pump. An adjusting member is arranged in the piston rod member so as to be adjustably positioned along the axis thereof and a regulating valve is provided for restricting the flow of hydraulic fluid from the first chamber in response to changes of pressure and the hydraulic passage. By means of the apparatus of the present invention, the stroke length of the piston member can be easily and precisely adjusted as well as stopped at a desired position.

Abstract: An apparatus for causing a low force input movement from a control rod to cause a corresponding movement in an output member by force amplification through hydraulic pressure. A piston is provided that has a greater pressure area on one side than on its other side. Orifice means are provided between a pressure chamber and a control chamber and between the control chamber and the reservoir such that as said second orifice means is varied, the piston will move until a null position is reached.

Abstract: A brake cylinder device for railway vehicles including a built-in automatic slack adjuster and a manually axially positionable piston for resetting the piston and piston rod relative to the slack adjuster when necessary, such as when replacing worn brake shoes, the piston rod being interconnected through a nut and screw, friction clutch, and a key to a manually rotatable member, which, when rotated causes axial displacement of the piston rod and piston to desired adjusted position relative to the slack adjuster.

Abstract: An apparatus for hydraulically cushioning the motion of reciprocating means is provided by first hydraulic cushioning means which is adapted to be contacted by the reciprocating means near the end of its stroke in the direction of the first hydraulic cushioning means, second hydraulic cushioning means adapted to be contacted by the reciprocating means near the end of its stroke in the direction of the second hydraulic cushioning means, and means for adjusting the position at which the reciprocating means contacts at least one of said first and second hydraulic cushioning means.

Abstract: In a pressure die casting apparatus, a die locking device in which a locking member is pivotably mounted on a frame and is movable into a position opposing a die part mount to have the force on the die part in the casting operation act through the locking member onto the frame substantially in the direction of that force. Another die locking device employs a main cylinder and piston assembly and an auxiliary cylinder and piston assembly with the chambers of the two cylinders interconnected whereby actuation of the auxiliary piston locks pressurized fluid in the main chamber. A sprue ejector mechanism has a plunger movable in a tubular piston rod, the end of the plunger being threaded to a collar and held to the piston rod and a cap threaded to the end of the piston rod, all for precise adjustment of the plunger in the die cavity.

Abstract: Apparatus for controlling the stroke of the movable member in a high pressure hydraulic machine, such as a hydraulic press, to permit the member to be positioned to an accuracy of 0.0005 inch and held at such position for a preselected time. The movable member is coupled to a piston movable within a cylinder which receives pressurized fluid. An adjustable threaded rod and nut arrangement is movable by movement of the piston within the cylinder, and an extension of the rod carries an actuating device for sequentially operating a first and then second valve. Operation of the first valve greatly reduces the speed of the movable member and operation of the second valve stops the movable member at its exact predetermined position. An adjustable time delay is coupled with the output from the second valve to maintain the movable member at such position for a preselected time thus maintaining the pressure on the article being formed in the machine.