Abstract: There is disclosed a blowout preventer having rams with cutting edges for shearing a pipe within the vertical bore through the preventer housing which rams carry means for gripping opposite sides of the pipe above the cutting edges of the rams, as the rams move toward one another to shear the pipe, and lifting the upper sheared end of the gripped pipe out of the path of means for sealing between the inner ends of the rams, as the rams continue to move toward one another.

Abstract: A positioning device capable of positioning a rod with a first piston fixed thereto into one of four positions selectively by means of a second piston disposed within a chamber A formed in a large-diameter cylinder portion and first, third and fourth pistons disposed within chambers B and C formed in a small-diameter cylinder portion. It is convenient to apply this positioning device to a select mechanism of a transmission or the like having four select positions.

Abstract: A piston for a fluid pressure chamber having an arcuate longitudinal axis. Such piston comprises an assemblage of two spherical bodies in side-by-side relationship and interconnected by a universal pivot. Each spherical body carries a circumferential piston ring receiving groove and piston rings are mounted in such grooves to provide a sliding and sealable engagement with the walls of the fluid pressure chamber as the piston moves along the curved longitudinal axis of such chamber.

Abstract: The disclosure describes a new type of pressure cylinder to provide clamping force while fabricating deep drawn metal parts. The piston is a hollow cylinder connected to the clamping pad. The drawing tools are connected to the draw ram by a rod passing through the hollow piston. This arrangement provides a smaller overall press height and an axisymmetric clamping force. In addition, the symmetry of the parts described means that the wear parts can be reversed to double their useful lives.

Abstract: A speed change control system for an automatic transmission for motor vehicles having a planetary gear mechanism and a brake band for altering the transmission ratio. The system is to tighten gradually the brake band. The system comprises a servo-piston, a piston rod secured to the servo-piston and to the brake band, and an accumulator piston axially slidably disposed in the bore of the servo-piston. The servo-piston is biased by a first spring for returning the servo-piston for releasing the brake band, and the accumulator piston is biased by a second spring. Apply side and release side oil chambers are formed on opposite sides of the servo-piston, and an accumulator oil chamber is formed by the accumulator piston in the bore. Pressure oil is applied to the apply side oil chamber, so that the servo-piston moves in a brake band engagement direction against the first spring. After that, the accumulator piston moves a predetermined stroke against the second spring.

Abstract: In a double-acting hydraulic press: an outer press ram having a cylinder formed therewithin for the piston of an inner press ram, the inner and outer ram cylinders in communication with one another and the rams being subject to a common hydraulic actuating means, each ram carrying a separate and distinct tool at its forward face, and means controllably feeding pressurized hydraulic fluid to an intermediate section of said inner ram cylinder, whereby to control the effective hydraulic force applied to said inner ram and the tool thereof.

Abstract: A trim-tilt device for marine propulsion devices wherein a cylinder and a piston rod slidably fitted in the cylinder are provided to be connected respectively with a propulsion device which in turn is connected to a hull so as to be rotatable in a vertical plane, and with the hull. A tilt piston is fitted to the tip of the piston rod and a free piston is arranged on the bottom side of the cylinder as opposed to the tilt piston and a trim piston is fitted to the tip of a pipe slidably fitted to the above mentioned piston rod. The trim piston is arranged on the opposite side of the tilt piston as opposed to the free piston and is slidably fitted in the above mentioned cylinder. Oil inlet and outlet ports are provided at both ends of the cylinder Stoppers and check valves are provided for controlling the oil pressure within the piston and cylinder arrangement. The trim-tilt device permits a trimming and tilting operation with a single cylinder.

Abstract: In a cylinder with a two-stage movement, a first piston moves in a housing, and in the first piston a second piston moves, which has a piston rod sliding in an end of the housing. On its side facing away from the piston rod, the second piston is provided with a guide member which is guided in the first piston. The first piston can be held in a position in which the piston rod is extended far out of the housing. With the aid of the second piston, the piston rod can perform a certain axial movement relative to the first piston, at the same time as guiding is effected with the aid of the guide member and the first piston.

Abstract: An adjusting drive operated by a pressure medium with a spring-loaded roller diaphragm secured to plates and displaceable within a housing by the pressure medium; the roller diaphragm actuates an adjusting member that is securely connected with a plate and extends out of the housing; in addition to its end positions, the adjusting member is also able to assume at least one intermediate position; the plates are thereby connected with each other by the roller diaphragm while a plate not directly connected with the adjusting member sealingly rests on a ring-shaped abutment projecting out of the inner wall of the housing in the intermediate position of the adjusting member.

Abstract: A three position fluid actuated device including a cylinder, end walls, a central wall dividing the cylinder into two chambers and a stop midway in one chamber. A piston is slidable in the other chamber and is attached to one end of an output shaft which extends beyond the opposite end wall. Two floating pistons are slidable on the shaft in the one chamber on opposite sides of the stop. A snap ring on the shaft displaces the floating pistons toward the central and end walls. Four ports in the end and central walls permit moving the shaft to three positive positions.

Abstract: A positioning device for transferring a plurality of carriages or the like into desired positions along a guide, and for holding the carriages in said positions, said device having at least one transfer bar extending along the guide and being movable reciprocally within certain end positions and each carriage having a locking mechanism which, in one condition, locks the carriage to the transfer bar for movement therewith and, in another condition, locks the carriage to the guide, wherein said locking mechanism comprises two pistons movable axially in relation to each other and provided with means for engagement with the guide and with the transfer bar respectively, a pressure medium channel leading to a space between said pistons and one of the pistons being provided with spring means so that with no pressure medium applied said one piston is forced into engagement by the spring force while, upon application of pressure between the pistons, said one piston is released and the other piston forced into its enga

Abstract: A fluid pressure operable servo positioner including a pair of operating piston units diametrally opposingly arranged relative to and abuttingly engageable with opposite sides of a mechanical operating member or lever for positioning the operating member in a preselected position determined by the degree of actuating pressure acting on the piston or pistons which are retractable by return springs, when relieved of actuating pressure acting thereon, completely out of contact with the operating member to an extent at which the operating member may be manually positioned, within a full range of positions, free of any resistance such as piston friction.

Abstract: A rock drill has a housing accommodating pistons defining working chambers. Rotary drive of a drill steel has an overrunning clutch and a screw pair. The screw pair is arranged between the pistons and is formed by outer and inner helical threads respectively provided on these pistons. One of the pistons is kinematically connected with the housing, and the other piston which cooperates, during the drilling, with a chuck receiving the drill steel shank is in force transmitting connection with the rotary drive of the drill steel.The invention is aimed at lowering vibration of the rock drill housing by arranging the screw pair of the rotary drive between the pistons.

Abstract: This invention concerns a control system for automatic safety gate-valves.The system comprises two hydraulically controlled pistons, the rod axis of which is parallel to the axis of the valve passage, and a connection by equal connecting rods, symmetrical to the axis of the gate-rod, between each of the piston rods and the gate-rod, with a release spring exerting a force contrary to the opening force acting on each piston.This system is specially designed for automatic gate-valves for oil installations.

Abstract: A brake with improved torque modulation, including first and second relatively rotatable elements, a plurality of brake discs carried by one of the elements to be rotatable therewith and axially movable thereon, a plurality of reaction plates carried by the other of the elements to be rotatable therewith and axially movable thereon, the discs and the plates being interleaved in alternating fashion to define a pack, an axially movable primary piston adapted for engagement with the pack, springs carried by the second element for biasing the primary piston towards the pack, an expandable chamber in the second element including the primary piston, the chamber being arranged so that when fluid under pressure is directed thereto, the piston will buck the springs, an axially movable secondary piston forming part of the chamber and in bucking relation to the primary piston, the primary piston having a larger surface area facing the interior of the chamber than the secondary piston, a stop for limiting movement of the

Abstract: In a tandem master cylinder main and secondary pistons are interconnected by a rigid sleeve. One end of the sleeve is secured to one of the pistons, and an inwardly projecting lip or flange on the other end of the sleeve provides an abutment for a head on an axial stem extending from the other piston towards the said one piston. The head is axially slidable in the sleeve and is introduced into it through an opening in the wall of the sleeve, which opening is connected by a longitudinal slot to the end of the sleeve which is provided with the lip or flange.

Abstract: The present invention is related to a piston-cylinder mechanism for the pivoting or tilting of the platform of a vehicle mounted goods elevator between a raised resting position and a lowered working position, including at least one piston rod slidably movable relative to a piston in the mechanism and uniformly movable by means of a driver together with the piston between a bottom position wherein the platform is lowered and an intermediate position determined by a stop limiting the piston travel, said piston rod being movable relative to the piston between said intermediate position and a position of maximum extension out of the cylinder wherein the platform is swung up, wherein a spring, adapted to be supplied with spring force when the piston rod is moved towards its position of maximum extension out of the cylinder, urges the piston rod from said position in a direction towards the bottom position thereby to initiate at all times a lowering of the platform.

Abstract: A unique double acting piston and cylinder assembly is disclosed wherein the assembly can be moved to any one of three positively determined positions by application of fluid pressure to any one of three ports.

Abstract: A position regulator is provided which is effective to control, via a control unit, a pressure medium circuit to operate a different working pressures. The regulator comprises two or more pistons dividing a common cylinder into a number of pressure chambers, the pistons being arranged for movement relative to one another. The invention provides stop means for each separate piston, each stop means being individually adjustable to produce different lengths of stroke for the respective pistons whereby the output piston rod from the cylinder is caused to adopt a number of axially determined limit positions depending upon the control pressure applied to respective pressure chambers.

Abstract: In an hydraulic actuating assembly for a vehicle shoe-drum brake comprising first and second relatively slidable members, the first member is provided with a longitudinally extending bore which is closed at one end and in which works a portion of the second member, and a sealed hydraulic chamber is defined within the bore between the closed end of the first member and the second member. One of the members incorporates an inlet port for the chamber and a vent port is located in a portion of the wall of that member to provide an indication, by external leakage of hydraulic fluid, of failure of the sealing of the chamber.

Abstract: The ends of travel of pneumatic jacks are controlled so as to obtain signals which are directly utilizable in fluidics by means of a device comprising a main jack-piston with a hollow operating stem fitted with a plunger and a positionally-adjustable regulating stem, a main cylinder and auxiliary cylinder having control ports for driving fluid and communicating with stationary fluidic control ports, and adjustable fluidic control means actuated in dependence on the position of the regulating stem with respect to a cylindrical slide-valve.

Abstract: A vehicle wheel spring brake actuator has a service braking piston and cylinder assembly and an auxiliary parking or emergency braking piston and cylinder assembly, the emergency braking piston being spring biassed towards a brake-applying position and normally held off by an opposing fluid pressure, upon release of which the spring force is transferred through the emergency braking piston and a force transferring member to the service braking piston to apply the brake. A quick release device is movable through a small distance to permit relative movement between the force transferring member to release the applied brake, the release device and the force transferring member extending through the emergency braking piston freely and with clearance.

Abstract: An actuating force generating device has a multi-stage cylinder body consisting of a plurality of cylinders having different diameters and arranged in series; a plurality of pistons slidably fitted in the cylinders, respectively; fluid ports each provided in the cylinders to discharge or introduce fluid from or into the cylinders; a container provided in the rear of the multi-stage cylinder body; a piston rod forming an actuating end projecting from the multi-stage cylinder body, said rod extending through a rod guide and being affixed to the forward piston; and a resilient member adapted to urge the rearmost piston forwardly.