Abstract: The invention relates to a method for constructing a gas-filled double-acting hydraulic cylinder (1) with gas spring action, comprising: —a cylinder sleeve (3) with a cylinder bottom (3a) and cylinder head (3b) —a piston/piston rod assembly (5) a hydraulic fluid seal on the piston (9) —a connection for the head-side chamber (13) to a hydraulic line; —a connection for the bottom-side chamber (15) to a hydraulic line, —a gland (20) with a bore, the gland being attached between the cylinder bottom (3a) and the piston (9), the piston rod (7) extending over the entire stroke of the piston rod through the bore, wherein the gland comprises two seals —(25), one for providing a seal with the cylinder sleeve (3) and one for providing a seal with the piston rod.

Abstract: The invention relates to a method for constructing a gas-filled double-acting hydraulic cylinder (1) with gas spring action, comprising: a cylinder sleeve (3) with a cylinder bottom (3a) and cylinder head (3b) a piston/ piston rod assembly (5) a hydraulic fluid seal on the piston (9) a connection for the head-side chamber (13) to a hydraulic line; a connection for the bottom-side chamber (15) to a hydraulic line, a gland (20) with a bore, the gland being attached between the cylinder bottom (3a) and the piston (9), the piston rod (7) extending over the entire stroke of the piston rod through the bore, wherein the gland comprises two seals (25), one for providing a seal with the cylinder sleeve (3) and one for providing a seal with the piston rod.

Abstract: A first aspect of the invention relates to a hydraulic pump unit (1) for feeding a hydraulic cab-tilting mechanism, comprising a casing (3) having at least two connecting ports (4,5) for the hydraulic cab-tilting mechanism, provided with a reservoir (6) for hydraulic fluid (7) and a hydraulic pump (8) which is connected to the reservoir and which can deliver hydraulic fluid to the connecting ports under working pressure required to operate the cab-tilting mechanism, a hydraulic circuit (9), fitted in the casing and connected to the connecting ports, the pump and the reservoir, and a hydraulic control valve (10) fitted in the hydraulic circuit, the hydraulic circuit further being provided with a mechanically-operable shut-off means (11), which, in the closed state, prevents the flow of hydraulic fluid under working pressure to the cab-tilting mechanism, which flow leads to operation of the cab-tilting mechanism.

Abstract: A hydraulic system, comprising a housing (1) on which a first and second connecting member (30,50) are fitted, for connecting the first and the second line respectively The first and the second line are provided with a first and a second insertion fitting (20,40) respectively, each connecting member (30,50) having a body (31,51) with an insertion bore (32,52) for an insertion fitting (20,40), which insertion bore (32,52) extends from an insertion side, and each connecting member (30,50) further comprising an elastic locking member (35,55). The part of the insertion bore (32,52) of each connecting member (30,50) extending between the insertion side and the locking member (35,55) forms a coding part (37,57), in which the coding part (37) of the first connecting member (30) differs with regard to one or more dimensions thereof from the coding part (57) of the second connecting member (50).

Abstract: A hydraulic tilting device for tilting the cab of a vehicle between a driving position, in which the vehicle can be driven normally, and a tilted position, in which, for example, maintenance can be carried out on a vehicle engine positioned beneath the cab. The tilting device comprises a double-acting tilting cylinder having a first and a second connection, a reservoir for hydraulic fluid and a pump having a single pumping direction, which pump has a suction port which is in communication with the reservoir and a single delivery port for delivering pressurized hydraulic fluid. The tilting device has a valve, in inlet passage of which is connected to there delivery port of the pump, which valve has an actuable shut-off member, so that in a first position thereof the delivery port is connected to the first connection of the tilting cylinder and in the second position thereof the delivery port is connected to the second connection of the tilting cylinder.

Abstract: The invention relates to a telescopic lifting column. The lifting column comprises a plurality of tube bodies which are arranged concentrically inside one another and are axially movable in each case with respect to each other. Furthermore, the lifting column comprises a hydraulic actuator unit which is arranged in the tube bodies so as to be operating in the axial direction. The hydraulic actuator unit comprises a first hydraulic cylinder-piston unit and a second hydraulic cylinder-piston unit connected with the first, the first cylinder-piston unit being connected to a first end of the telescopic lifting column and the second cylinder-piston unit being connected to a second end of the telescopic lifting column. The first cylinder-piston unit is of the type having a first variable operating chamber and a second variable operating chamber.

Abstract: A hydraulic tilting device for tilting the cab of a vehicle between a driving position, in which the vehicle can be driven normally, and a tilted position, in which, for example, maintenance can be carried out on a vehicle engine positioned beneath the cab. The tilting device comprises a double-acting tilting cylinder having a first and a second connection, a reservoir for hydraulic fluid and a pump having one single pumping direction, which pump has a suction port which is in communication with the reservoir and one single delivery port for delivering pressurized hydraulic fluid. The tilting device has a valve, the inlet passage of which is connected to the delivery port of the pump, which valve has an actuable shut-off member, so that in a first position thereof the delivery port is connected to the first connection of the tilting cylinder and in the second position thereof the delivery port is connected to the second connection of the tilting cylinder.

Abstract: The invention relates to a telescopic lifting column. The lifting column comprises a plurality of tube bodies which are arranged concentrically inside one another and are axially movable in each case with respect to each other. Furthermore, the lifting column comprises a hydraulic actuator unit which is arranged in the tube bodies so as to be operating in the axial direction. The hydraulic actuator unit comprises a first hydraulic cylinder-piston unit and a second hydraulic cylinder-piston unit connected with the first, the first cylinder-piston unit being connected to a first end of the telescopic lifting column and the second cylinder-piston unit being connected to a second end of the telescopic lifting column. The first cylinder-piston unit is of the type having a first variable operating chamber and a second variable operating chamber.

Abstract: A hydraulic circuit comprising at least two double acting hydraulic piston-cylinder devices, for opening and closing a folding roof of a vehicle, with both ends of each piston-cylinder device each connected to a conduit supplied with pressurized fluid by a common hydraulic pump and to a return conduit leading to a source of hydraulic fluid, via 3/2 electrically activated valves. The 3/2 valves include a main ball (22) and seat (22a), with a check valve (32) of the ball seat type upstream of the main ball seat in a connection to the conduit supplied with pressurized fluid.

Abstract: A hydraulic actuating unit for raising a hospital bed includes a reservoir, a hydraulic piston cylinder device the cylinder of which has its ends connected to the reservoir through a supply conduit that contains a hydraulic plunger pump with suction and pressure valve means and through a return conduit which contains an orifice in a normally closed relief valve. A branch conduit leads to a hydraulic liquid accumulator from the supply conduit at a location between the cylinder and pressure valve means. A multiple pilot operated check valve of the differential type is provided in the branch conduit towards the accumulator. The largest and smallest end faces of the differential spool member are subject to the pressure in the branch conduit while the differential area of the spool member is subject to the pressure in a conduit which leads from the return conduit at a location between the orifice and the relief valve.

Abstract: Disclosed is a cabtilt system comprising conventional hydraulic tilting cylinders, a cock sensing member, and a synchronizing valve which causes one of the hydraulic tilting cylinders to slow or stop its motion until the other cylinder catches up with it if the cock sensing member senses that the cab is cocking as it tilts.

Abstract: Disclosed is apparatus for permitting hydraulic lost motion between the push chamber and the pull chamber of the tilt cylinder(s) for a tiltcab truck. The apparatus comprises a pilot-operated check valve having a through passage (a) which is part of a hydraulic connection between the push chamber and the pull chamber and (b) which is only shut off when hydraulic pressure is applied to the push chamber(s) of the tilt cylinder(s).