Abstract: A variable-displacement piston-cylinder device may be adapted for providing work output, and/or for pumping or compressing fluids. The piston-cylinder device defines two or more coaxial cylindrical expansion chambers between a piston having two or more coaxial and conjoined piston members, and a correspondingly-shaped cylinder. Substantially any combination of the expansion chambers may be activated or deactivated in order to vary the effective displacement of the piston-cylinder device. The effective displacement of each piston-cylinder may be changed in mid-operation in order to reduce power output and fuel consumption (or pumping or compressing capacity), without introducing vibration. In addition, a control system is provided for managing the effective displacement of each piston-cylinder according to output required, desirable operating parameters, and other parameters that can effect the operation of the device.

Abstract: An actuator assembly that has a constant net pressure area telescoping piston. The actuator assembly has a cylindrical housing; nesting, telescoping pistons; a central plug; an outer cap; and a vent. The cylindrical housing has an interior surface and a base that terminates at an open end. The nesting, telescoping pistons are located in the housing and can extend past the housing open end. The telescoping pistons have an outer piston slidably sealed against the housing and an inner piston that is slidably sealed against the outer piston. The outer piston has a first end proximal to the housing base, and a second end distal to the housing base. The inner piston has an open end proximal to the housing base, and a closed end distal to the housing base. The central plug extends from the base and into the telescoping pistons. The central plug is in pressurized communication with the inner piston and is engagable with a pressurized fluid source. The outer cap has a first and a second member.

Abstract: A high speed and high load cylinder device is constructed by connecting a piston of a high speed cylinder (1) having a smaller pressure receiving area and a piston of a pressurizing cylinder (2) having a large pressurizing area. The device is provided with a hydraulic circuit for supplying a hydraulic pressure to the high speed cylinder and the pressurizing cylinder. The device has a sequence valve (5) at an intermediate position in a passage (2e) providing in the piston of the pressurizing cylinder for communicating an upper chamber (2.sub.1) and a lower chamber (2.sub.2) of the pressurizing cylinder for opening and closing the passage depending upon a pilot pressure. A pilot pressure is supplied for closing the sequence valve by supplying the pilot pressure to the sequence valve. A high speed/pressurizing switching valve (12) is provided at an intermediate position in a piping (11) supplying the hydraulic pressure to the upper chamber of the pressurizing cylinder in the hydraulic circuit.

Abstract: A clutch hydraulic slave cylinder comprising a cylinder body, a primary piston sealingly reciprocable relative to the body and co-operating with the body to form a first fluid chamber within said body, and a secondary piston sealingly reciprocable relative to the primary piston and co-operating with the primary piston to form a second fluid chamber. the second fluid chamber is connected to the first fluid chamber through a valve means. The primary piston is biased by a spring means from a fully retracted condition to an at-rest condition in which it can exert a pre-load on a clutch bearing, and said valve means is open when the primary piston is in the fully retracted condition, and is closed when the primary piston is in the at-rest condition.

Abstract: An automotive hydraulic braking system includes a pivoted brake lever coupled to a master hydraulic cylinder assembly which in turn is coupled by a brake line to a plurality of hydraulically actuatable calipers. A mechanical brake pressure intensifier is provided in-line between the master cylinder and the calipers. Pedal travel is controlled according to a developed formula to approximate preestablished industry standards set for conventional vacuum-assisted hydraulic braking systems.

Abstract: To excavate sticky soil such as clayey soil, left and right buckets of a clamshell bucket are slightly inclined, thereby reducing the force to pull the buckets from a hole. The clamshell bucket includes left and right buckets which are closable, thereby holding soil, and a hydraulic cylinder having a stroke reserve so as to be further extendible after the buckets are closed, whereby the closed buckets can be displaced sidewardly relative to the vertical.

Abstract: A hydraulic system having a first bucket leveling circuit for controlling leveling of the bucket during raising of the boom and a second bucket leveling circuit for controlling leveling of the bucket during lowering of the boom. The second bucket leveling circuit includes a motor-type flow divider having first and second shaft connected motor sections. Controls are operative when the boom control valve supplies fluid under pressure to the rod end of the boom cylinder for passing fluid from the piston end of the boom cylinder to the inlet of the first and second sections of the motor-type flow divider, and for preventing passage of fluid from the piston end of the boom cylinder to the inlet of the first flow divider.

Abstract: A hydraulic fluid Pressure-operated actuator comprises a first cylinder assembly having an output which operatively carries a second cylinder assembly such that an axial output force is effected from an output shaft of the second cylinder assembly, the output from the second cylinder assembly is a fast forward output stroke which is followed by a greatly increased high pressure force generated by the first cylinder assembly and effected through the output shaft of the second cylinder assembly.

Abstract: An actuator for a friction clutch having a diaphragm includes coupling means comprising a first part associated with the clutch actuating linkage, and a second part associated with the actuator proper. The actuator, of the fluid operated type, comprises a main piston working in a main cylinder and defining with it a control chamber. A secondary piston works within the hollow bore of the main piston to define within the latter a wear compensating chamber. The main piston carries a shut-off valve for bringing the control chamber and the wear compensation chamber into communication with each other when the clutch is in its engaged position. The actuator also includes a booster spring for applying additional force to the diaphragm, such that the characteristic of the diaphragm has a positive gradient over the whole travel between the engaged and disengaged positions of the clutch.

Abstract: A pneumatically actuatable linear drive for automatic spot welding machines includes a cylinder, a piston rod with segments and pistons and an intermediate bottom between the pistons for dividing the cylinder into pressure chambers. An axial conduit in the segments has a check valve. Radial conduits communicate between the axial conduit and the pressure chambers. Air line connections and a throttle valve lead into the pressure chambers. One piston on one segment moves toward and away from the closed end into end and terminal positions for closing and opening the radial conduits. The end and terminal positions of the one piston are determined by a cap screw of the check valve having an axially parallel conduit and by a spring on one of the segments. A connecting conduit contains the throttle valve. The intermediate bottom has a peripheral annular conduit communicating with one of the air line connections and through the connecting conduit with one of the pressure chambers.

Abstract: This invention relates to a multiple jack incorporating at least three elements, viz. two pistons and two cylinders which define large and small chambers of a first cylinder, and large and small chambers of a second cylinder.According to the invention: a) a first inner conduit connects the large chamber of the first cylinder to a first outer conduit; b) a second inner conduit connects the small chamber of the first cylinder to a second outer conduit; c) a third inner conduit connects the large chamber of the second cylinder to a third outer conduit; and d) a fourth inner conduit connects the small chamber of the second cylinder to a fourth outer conduit.One application is the production of a telescopic jib presenting a satisfactory flexibility of use.

Abstract: The subject invention comprises a hydraulic pressure intensifier (10) including a cylinder (42) having a fluid inlet (44) at one end and a fluid outlet (46) at the other end. Two telescopically disposed pistons (54, 56) are slideably supported between the inlet (44) and outlet (46) ends of the cylidner (42). A spring (60) extending axially through the cylinder (42) urges the pistons (54, 56) toward the inlet end (44) of the cylinder (42). A spring biased valve member (70) seals a flow passage (62) extending through the pistons (54, 56) when the fluid pressure reaches approximately 150 psi at the inlet (44) to the cylinder (42). A pin (68) fixed to the inlet end (44) of the cylinder (42) actuates the valve member (70). The pistons (54, 56) move first in unison and then separately toward the outlet end (46) of the cylinder (42) as the hydraulic pressure increases at the inlet end (44).

Abstract: The subject invention comprises a hydraulic pressure intensifier (10) including a cylinder (42) having a fluid inlet (44) at one end and a fluid outlet (46) at the other end. Two telescopically disposed pistons (54, 56) are slideably supported between the inlet (44) and outlet (46) ends of the cylinder (42). A spring (60) extending axially through the cylinder (42) urges the pistons (54, 56) toward the inlet end (44) of the cylinder (42). A spring biased valve member (70) seals a flow passage (62) extending through the pistons (54, 56) when the fluid pressure reaches approximately 150 psi at the inlet (44) to the cylinder (42). A pin (68) fixed to the inlet end (44) of the cylinder (42) actuates the valve member (70). The pistons (54, 56) move first in unison and then separately toward the outlet end (46) of the cylinder (42) as the hydraulic pressure increases at the inlet end (44).

Abstract: A hydraulically-operated support device for semitrailers is disclosed comprising a hydraulic cylinder semitrailer support and a pump subassembly having three independently operable pumps for generating and controlling the hydraulic operating pressure. The hydraulic cylinder semitrailer support has an extending piston in an extending cylinder, in the bottom end of which is formed a load-raising cylinder for a load raising-piston. A first annular space is formed between the extending piston and the extending cylinder and a second annular space is formed between the load-raising piston and the load-raising cylinder. The annular spaces allow application of pressure in the retraction direction. The pump subassembly comprises an extending pump acting on the extending piston, a load-raising pump acting on the load-raising piston and a retracting pump acting on the annular spaces.

Abstract: A full free lift mast assembly having a first pair of spaced apart uprights, a second pair of spaced apart uprights mounted on the first pair of uprights and elevationally movable therealong and a carriage mounted on the second pair of uprights is provided. A first mast lift jack is connected between the first and second pairs of spaced apart uprights, and first and second interconnected carriage lift jacks are pivotally connected to and between the second pair of spaced apart uprights and the carriage. A first connecting arrangement connects a cylinder of the first and second carriage lift jacks and maintains the first and second carriage lift jacks parallel, in a preselected overlapping relationship relative to each other. Therefore, bending of the carriage lift jacks, fluid leakage, missequencing and the like have been substantially reduced. The full free lift mast assembly is particularly suited for use on a material handling vehicle.

Abstract: Level lifting and lowering of a working implement in combination with a hydraulic boom is provided through a hydraulic circuit and valve including a shuttle check valve, a rotary flow divider and a counterbalance valve. Selective operation results in the working implement being raised or lowered in a level displacement relative to the ground.

Abstract: A triple action, multi-segment, telescoping hydraulic ram comprising a plurality of coaxially nested, extensible cylinders adapted to be selectively extended or retracted, and a pair of lower diameter, sweep cycle cylinders adapted to be operated independently of the larger cylinders. The ram is ideal for the garbage reception area defined within the cargo area of conventional garbage trucks, for operating the compression platen for moving and compacting garbage. A terminal pin eye associated with the smaller sweep cycle cylinder may be coupled to a stationary support to rigidly brace the ram. Full extension and "sweep cycle" operation is effectuated through various input passageways defined in the pin eye through which high pressure hydraulic fluid is inputted to the ram in conjunction with various annular transmittal passageways to effectuate cylinder operation.

Abstract: A hydraulic adjustment apparatus as is for instance used to adjust a roller of a rolling mill has a cylinder forming a first cylinder chamber and having a first cylinder surface directed backwardly in a predetermined direction in the first chamber. A first piston is displaceable forwardly and backwardly in the direction in the first chamber relative to the cylinder and has in this chamber a forwardly directed first piston face of a predetermined first piston area. The first piston is formed with at least one second chamber receiving a forwardly and backwardly displaceable second piston having a forwardly directed end engageable with the first chamber surface. This second piston in turn has a second piston face of a predetermined second piston area substantially smaller than the first piston area and directed backwardly in the second chamber.

Abstract: Hydraulic actuating apparatus with digital input comprising a movable output member spring biased to a neutral position and capable of moving to one or other of two working positions under the effect of opposing hydraulic means, themselves controlled by binary-type control members;To create two additional working positions for the movable output member (10), the invention provides for each of the driving means to be composed of two active areas (s.sub.1, s'.sub.1 ; s.sub.2, s'.sub.2) acting successively on the output member (10), and for the putting of the first area under pressure to be caused by one of the control members (EV.sub.1, EV.sub.2) while that of the other area is caused by the other control member provided that the output member has already completed a first displacement step in the required direction;Particular application to the control of double-acting hydraulic actuators with two rates of displacement in each direction.