Abstract: The subject of this invention is a column (13) of a medical device such as a gynecological examination table or a birthing bed. The aim of the invention is to provide a method of vertical movement of the medical device quickly and with sufficient range. This is achieved by mounting a column drive by at least three successive linear drives and two connecting elements. The connecting elements enable connecting the successive linear drives off-level so that all the drives abut close to each other in the lowest position and a lower possible minimum position is achieved. The advantage of the telescopic column solution according to the present invention is also that it is able to achieve a higher maximum position by means of providing each two segments with their own linear drive. This also ensures much more efficient and faster vertical shift.

Abstract: A cutting machine for cutting up pre-compressed meat strands into slices and a method for slicing pre-compressed meat strands, wherein the blade is moved forward in the feed direction to a limited extent after the blade has completely cut off a slice, and is either subsequently or simultaneously moved backward in the transversal direction. In this way, the forward movement of the meat strand to cut off the next slice can be started earlier.

Abstract: A hydraulic system for a machine is disclosed. The hydraulic system may have a pump, a tank, a first actuator with a head-end and a rod-end, and a first valve arrangement configured to control fluid flow from the pump to the first actuator and from the first actuator to the tank. The hydraulic system may also have a second actuator with a head-end and a rod-end, and a second valve arrangement configured to control fluid flow from the pump to the second actuator and from the second actuator to the tank. The hydraulic system may further have a third valve arrangement fluidly connected between the first and second valve arrangements to receive pressurized fluid from the pump in parallel with the first and second valve arrangements. The third valve arrangement may be configured to facilitate fluid regeneration of and supplemental flow to at least one of the first and second actuators.

Abstract: A hydraulic valve assembly includes a pilot operated proportional poppet valve in which the main poppet moves in response to pressure in a first control chamber. The pressure in a first control chamber is governed by a pilot poppet and movement of the main poppet controls fluid flow between a first inlet and a first outlet. A shadow poppet valve has a shadow poppet that controls fluid flow between a second inlet and a second outlet in response to pressure in a second control chamber. The first and second control chamber are connected together whereby the pilot operated proportional poppet valve and the shadow poppet valve open and close together. A unique hydraulic system utilizing a plurality of these hydraulic valve assemblies to operate two operators alternately in parallel or in series is described.

Abstract: The invention relates to a hydraulic multiposition valve, in particular a valve for selecting the steering modes of vehicles with multi-axle steering, having one or more position-seat valves (31, 33, 35, 37, 39, 41, 43), which have at least two switching positions and which communicate via lines for the hydraulic medium with one another and with a number of controlled connections (A, B, C, D; L, R) in such a manner that the desired switching positions of the multiposition valve (13) can be selected by the actuation of the seat valves (31-43); and having an actuating arrangement (29) for actuating the seat valves (31-43); the actuating arrangement (29) can be locked in detent fashion in the switching positions of the multiposition valve (13).

Abstract: A high-pressure valve assembly having a valve body that defines a preferably cylindrical valve cavity, a fluid inlet, a fluid outlet and a plurality of valve ports; and a fluid pressure intensifier assembly having a plurality of piston-plunger assemblies and utilizing the high-pressure valve assembly to distribute the working fluid. The valve assemblies have a valve rotor rotatably mounted within the valve cavity. In one embodiment, the valve rotor divides the valve cavity into a high-pressure region in communication with the fluid inlet and a low-pressure region in communication with the fluid outlet. As the valve rotor rotates, at least one and preferably three or more valve ports communicate with the power chamber and at least one and preferably three or more valve ports communicate with the discharge chamber.

Abstract: A flow reinforcement directional control valve that is capable of reinforcing a pressure fluid to two actuators, can be formed as compact and yet is capable of flowing a return fluid out of a single actuator into a tank is provided, wherein a valve block 20 has a spool bore 21 in which a first spool (22) and a second spool (23) are slidably inserted; in which the first spool (22) is adapted to be held at a neutral position thereof by a first spring (36) and to be displaced by a pressure fluid in a second pressure receiving chamber (47) to a position thereof for supplying the fluid to an actuator; and in which the above mentioned second spool (23) is adapted to be held at a neutral position thereof by a second spring (41) and to be displaced by a pressure fluid in a first pressure receiving chamber (42) to a position thereof for flowing a return fluid into a tank and to be displaced by a pressure fluid in a third pressure receiving chamber (52) to a position thereof for supplying a pressure fluid to an actuato

Abstract: The electrohydraulic adjusting device for actuating a device for adjusting at least one camshaft of an internal combustion engine relative to its crankshaft has two differential pistons each of which serves to adjust a camshaft (intake camshaft or exhaust camshaft). Each of the two differential pistons have a small effective piston surface which is acted upon with pressure by a pump. An independent pressure control valve is associated with each of the pressure chambers on a larger effective piston surface, via which valve, the pressure in this pressure chamber can be controlled independently of the other differential piston.

Abstract: A hydraulic control system for a jet aircraft engine has an electronic control that commands a pair of torque motors to ultimately control the position of each one of a plurality of two-position, "latching" hydraulic actuator valves. A first torque motor is operable with a three-position, on/off hydraulic valve. The second torque motor operates in conjunction with a second valve to control the linear position of the spool of a multiplexer selector valve. The multiplexer selector valve has a plurality of positions that the spool can be linear translatable to. At each position is located a pair of control ports to which are ultimately connected one side of each of a pair of corresponding hydraulic actuator valves. The actuator valves may comprise fuel or air valves.

Abstract: Fluidic control of a number of remote functions is achieved by a single servo controlled linearly actuated distribution valve (29) in conjunction with a like number of bistable hydraulically actuable holding relays (17,19,21) the individual states of which are controlled by the distribution valve. Each holding relay supplies one of two pneumatic signals to an associated remote device (11,13,15). Holding relay or distribution valve motion is only required when a change in a remote function is required. The distribution valve is also adapted to provide a fail-safe signal (79) to all remote devices simultaneously to set the individual remote functions to a desired safe condition.

Abstract: A device for controlling hydraulic steering clutches and brakes in a crawler vehicle such as a bulldozer has a simple structure so as to be manipulated by a monolever. The device comprises a single steering lever (5), four proportional pressure control valves (1), (2), (3), (4), left and right steering clutch pistons (7), (7a) and left and right brake cylinders (8), (8a). The four valves are composed of two sets of valves, one set of two valves for steering clutches, in which the timing of the rise of hydraulic pressure is earlier, and one set of two valves for brakes, in which the timing of the rise of hydraulic pressure is later than the former.

Abstract: A multiplexed hydraulic control system in which high force margins for the multiplexer are achieved by employing hydraulic oscillators as the multiplexer driving means. The multiplexer is typically in the form of a hydraulic cylinder having an input port and a plurality of output ports, with an operator in the cylinder for individually connecting the input port to the output ports. The hydraulic oscillator is mechanically coupled to the multiplexer operator, and oscillation of the former causes oscillation of the latter to sequentially connect the input to each of the outputs. Various means are taught for initiating reversal of the oscillator and controlling the oscillation speed.

Abstract: The present invention is directed to a hybrid hydraulic system for a work vehicle having both an open center hydraulic circuit and a close center hydraulic circuit. An internal combustion engine drives a fixed displacement pump and a variable displacement pump. The fixed displacement pump provides hydraulic fluid to the open center circuit which directs hydraulic fluid to a steering circuit and the working circuit through a priority valve. The variable displacement pump provides hydraulic fluid to the close center circuit which directs hydraulic fluid to a braking circuit and a pressure reduction circuit. The pressure reduction circuit directs hydraulic fluid to a pilot control system, a clutch cutoff and a differential lock out. Both pumps receive hydraulic fluid from a common sump and a common suction line. The braking circuit comprises two independent braking circuits.

Abstract: A hydraulic drive system for a machine element performing in one work cycle a sequence of motions comprising a rapid feed motion, a working stroke under load and an oppositely directed rapid-return motion. The drive element includes a hydraulic cylinder having three working surfaces A.sub.1, A.sub.2, A.sub.3. Motion control is effected by an electro-hydraulic follow-up control valve with a pre-setting device controlled by a stepping motor and a mechanical actual-value feed-back device. During rapid feed motion, the relatively small working surface A.sub.1 is subjected to the output pressure of the follow-up control valve only, while during the working stroke the pressure acts additionally on the working surface A.sub.3. The rapid-return movements of the piston of the cylinder are controlled by applying pressure to the working surface A.sub.2, or by relieving pressure from the two other working surfaces A.sub.1 and A.sub.3.

Abstract: In a sensitive analytical instrument having an optical bench carried by a base member, new and improved vibration and shock isolation apparatus which includes three spaced pneumatic mounts interposed between the optical bench and the base member to provide vibration and shock isolation therebetween, each of the mounts having a preselected optimum linear range of operation, a source of pressurized gas, apparatus for individually controlling the inflation and deflation of each of the mounts with pressurized gas to maintain actual operation of each of the mounts within its preselected optimum linear operating range.

Abstract: The hydraulic assistance device incorporates a casing (10) enclosing first and second sliding components (18, 20) arranged in line, the first component (18) being capable of being displaced under the effect of the displacement of a pushrod (34) and the second component being capable of being displaced through the intermediary of a hydrostatic connection, and associated with each component (18, 20) is a valve mechanism (36, 46) in a respective hydraulic circuit between a source of fluid under pressure and a respective braking circuit (I, II), characterized in that the first and second components (18, 20) each constitute a piston sliding in a bore (14) in the casing (10) and each encloses a valve assembly (26, 40; 36, 46) each controlled by a plunger (30, 44), the plunger (30) of the first valve assembly (26, 36) being actuated by the pushrod (34), and the plunger (44) of the second valve assembly (40, 46) being actuated by the hydrostatic connection between the two pistons (18, 20).

Abstract: Valves regulating the supply of hydraulic fluid to hydraulic cylinders of an hydraulic walking mine-roof support are controlled by apparatus comprising an axially-movable switching shaft provided with cams which is rotatable into successive switching stations where it is immobilized by spring-loaded stop pins to that the cams bear on tappets to actuate the respective valves, there being a switching spring acting on the shaft to return the shaft to its initial position of rest after it has been axially displaced and rotated out of that position of rest.

Abstract: A power assisted steering system and a steering assembly for such a system. The steering assembly has a steering output comprising an arm 6 displaceable through a toothed sector 7 by a racked piston nut 3 drivingly engaging a worm shaft 7 rotatable by a steering input shaft 12. The piston 3 and its cylinder 2 provides a first servomotor for power assisting the steering output. The first servomotor is powered by a first hydraulic system 16 comprising a rotary valve 10 which is responsive to the steering input to control fluid pressure to the first servomotor. The steering system also includes a second hydraulic system 25 comprising an axially responsive spool valve 21 which controls fluid pressure to operate a second servomotor 28 coupled to the steering output arm 6. The rotary and axially responsive valves 10 and 21 are axially coupled together by the shaft 7 which is axially displaceable to control operation of the valve 21.

Abstract: A hydraulic control device is incorporated in a hydraulic control system for a mine roof support assembly. The hydraulic control system includes a plurality of hydraulic control valves which are controlled by the hydraulic control device. The hydraulic control device is constituted by a longitudinal slide valve having a slide member longitudinally reciprocable in a slide valve housing. A rotary drive is provided for moving the slide member within the slide valve housing. The slide member is provided with two axial bores each of which opens into a respective pair of axially-spaced radial bores which terminate at the peripheral surface of the slide member. A first radial bore of each axial bore opens into a respective annular groove formed in the slide valve housing. The second radial bore of each axial bore is connected to a respective group of control ports provided on the slide valve housing.

Abstract: Two pistons (5, 8) are mounted in the same casing (1) so as to slide in a sealed manner, the two pistons (5, 8) being firmly fixed to one another and having corresponding actuating chambers (21, 22; 23, 24) which are separated from one another and are supplied sequentially by two distribution valves (A, B) which are situated in the casing (1) and are actuated by the input shaft (14). The second piston (8) is formed by an extension (7) of the first piston (5) and its corresponding actuating chambers (22, 24) are formed in the piston structure (5, 8) and by a housing (4) in the casing (1), respectively, the housing (4) being coaxial with the main housing (3) for the first piston (5). The two valves (A, B) are advantageously of the type having a star-shaped rotor (30, 40).

Abstract: A booster having a vacuum powered booster section and a hydraulic powered booster section which are normally actuated together to supply boosted force to a master cylinder. When the air valve of the vacuum booster section is operated to cause atmospheric air to enter the variable pressure chamber of the vacuum booster, it also engages and moves the hydraulic booster control valve to restrict hydraulic fluid flow therethrough, causing the hydraulic booster section control valve to be actuated to create a hydraulic pressure differential across the power wall of the hydraulic booster section. Both booster sections deliver boosted force through the output member of the hydraulic booster section to the master cylinder. Either booster section is operable when for any reason there is no power available for actuation of the other booster section.