Abstract: A travelling clamp unit of the type for extending and retracting a T-head clamping cylinder into and out of a T-slot of a press has a main frame which supports clamping cylinder drive means and the clamping cylinder when it is in a parked position in which it is retracted from the T-slot of the press. The main frame has rails which support the clamping cylinder T-head in the parked position and which are removable from the main frame so that the T-head can be dropped out of the bottom end of the main frame for removing the clamping cylinder from the travelling clamp unit.

Abstract: An apparatus for absorbing vibrations in a structural member, such as in an aircraft fuselage, has first and second plates for attaching to the structural member. A mass, which is suspended between the plates, includes a first block connected to the first plate by a first spring and a second block connected to the second plate by a second spring. The springs may be formed by metal straps which allow the mass to move along one axis or by rods which allow two axis movement of the mass. One sensor produces a signal indicating vibration of the structural member and another sensor produces a signal indicating vibration of the mass. A mechanism connected to the first and second block responds to a control signal by varying a distance between the first and second block to alter stiffness of the first and second springs.

Abstract: The invention relates to a hydraulic circuit for the sequential control of two or more hydraulic cylinders and more particularly for opening and closing the folding roof a cabriolet type vehicle, in which the cylinder space under the piston of each piston cylinder device is selectively connectable to a hydraulic pressure source or to a reservoir for hydraulic fluid, and an additional valve device is provided by which the cylinder space above the piston is also connectable to the pressure source for at least some of the piston cylinder devices. The cylinder spaces above the pistons are hydraulically connected and the additional valve device is constituted by a common electrically operated valve for the piston cylinder devices, by which the cylinder spaces above the pistons are jointly connectable to either the pressure source or the reservoir.

Abstract: A tube bender angle indicator is attached to the handle of a manual tube bender and has a frame to which angle indicia are applied which define an apex through which a pointer is pivotally connected to the frame. A bubble level vial is secured to the pointer so as to indicate that the bend angle has been achieved which the pointer is pointing at when the bubble is in its horizontal reference position.

Abstract: A hydraulic circuit for opening and closing of a folding roof has at least two (pairs of) cylinders, one of which is adapted to open and close the folding roof and the other of which is adapted to lock the roof upon closing. The hydraulic circuit also has electrically operated valves provided in the circuit in such a way that the closing pressure within the roof cylinder is released rapidly as soon as the front roof edge gets within the catching area of the lock member, after which the lock cylinder will immediately close. This prevents the roof from moving in the closing direction too far, which would involve the tendency of the roof to "spring back", and avoids the chance of "miscatching" by the lock member.

Abstract: A system for tightening a threaded fastener with a hydraulic wrench has a pumping unit which measures parameters representative of the torque applied to the fastener and the angle of advance of the fastener, remote from the wrench. The pump measures pressure as a parameter representative of torque and measures flow rate, pump speed (for a fixed displacement pump), or time (for a fixed displacement pump driven at constant speed) as a parameter representative of the angle of advance of the fastener. A ratchet-type hydraulic wrench is used, and the pressure versus angle data produced in tightening a fastener is manipulated to discard irrelevant portions and smooth relevant portions to provide data representative of torque and angle during the tightening process from which to determine a final stopping parameter for terminating tightening. The system also has a calibration fixture for determining the volumetric rate of angle advance for a given wrench.

Abstract: An active vibration isolation system (10) includes a plurality of stiff actuators, such as piezoelectric motors (12a-c; 284, 350) which support a small mass (18) inside of a case (300). A passive isolator (20) is interposed between the small mass (18) and the payload mass (M.sub.p). In the instance where the stiff actuators are piezoelectric motors, the sidewalls of the case (300) are used to provide compressive force along the variable length of each of the horizontal piezoelectric motor elements (284, 350) to prevent damage to same. Compensation circuitry (24) is connected between velocity sensors (17) and the stiff actuators to control the variable length thereof in this move-out-of-the-way system (10) and to compensate for resonating modes. Optionally, a payload mass velocity sensor (26) and associated circuitry may be used to provide additional control.

Abstract: A radial piston pump with pistons which pump into a circumferential pressure passage has the passage sealed on its outer side by a plastic annular member of a trapezoid-shaped cross-section. The longer parallel side of the cross-section faces radially inwardly and includes a circumferential groove for receiving a resilient O-ring which biases closed pressure valves located between the pistons and the passage. The annular member is adapted to be inserted radially inwardly into the circumferential pressure passage by expanding it and allowing it to contract into the passage. A radially inner side of the circumferential passage is, at a location between two adjacent cylinders, connected to a passage that extends radially inwardly and that is connected to an axial passage that leads to a pressure connection.

Abstract: A bidirectional flow control valve has one port co-axial with a tubular spool and another port opening to the side of the spool, with openings formed in the sidewall of the spool to establish communication between the two ports. The end of the spool adjacent to the one port abuts the brim of a tubular hat-shaped insert which extends inside the lumen of the spool to a closed end on the distal side of the other port. Openings are formed in the sidewall of the insert which are in communication with openings in the sidewall of the spool via an annular groove in the exterior of the insert. The insert reacts against flow forces, helps equalize pressures from one end of the spool to the other, and does not increase the pressure drop across the valve.

Abstract: A piezo-electrically actuated hydraulic valve has a nozzle type seat and a piezo-electric actuator in a plane orthogonal to the axis of the nozzle. The actuator includes a piezo-ceramic layer laminated to an electrode sheet, so that the composite is in sheet form and parallel to the plane of the seat. The electrode sheet has opposite edges which extend beyond the piezo-ceramic layer and are clamped by the housing of the valve so that the center of the actuator is positioned over the seat, and in the preferred embodiment normally closes the seat. When an electric field is applied to the piezo-ceramic layer, the actuator bows or dishes so as to displace relative to the nozzle. The electric field may be applied proportionally, in which case the actuator displaces proportionally to the field applied, the field may be applied as a pulse width modulated signal, in which case the displacement of the actuator also modulates.

Abstract: A linear preload fluid power operated latch has two coaxial pistons, one slidable inside the other and the other slidable within a cylinder. The one piston slides inside the other to cam dogs which are slidable in slots of a nose which is secured to the other piston so as to engage an undercut in a cup in which the nose is received. After the dogs are engaged in the cup, which secures the latch, both pistons are retracted to apply a linear preload force between the two bodies being latched. In one embodiment, the pistons are moved in both directions under fluid pressure and in another embodiment, both pistons are returned by compression springs. In either case, the cup is drawn closer to the cylinder with a certain preload force, to latch a body to which the cup is attached to a second body to which the cylinder is attached with that preload force.

Abstract: An active vehicle suspension employs a multi-point support system between a vehicle's chassis and cab. Each support point has an isolator which includes a linear hydraulic actuator that is connected at its quiet end to the payload by a passive vibration isolator and is connected at its vibrating end to the chassis. Each isolator also has a support spring to off-load the majority of the weight of the cab from the hydraulic actuator. An accelerometer is mounted to sense movement at a point between the linear hydraulic actuator and the passive vibration isolator. An electrical signal produced by the accelerometer is processed to operate a hydraulic valve that controls movements of the hydraulic actuator so that transmission of vibrations from the chassis to the cab is attenuated.

Abstract: A piezo-electrically actuated fluid control valve has a nozzle type seat, a magnet opposite from the seat, and a piezoelectric actuator in sheet form between the seat and magnet. The actuator includes a piezo-ceramic layer laminated to an electrode sheet, so that the composite is parallel to the seat and a surface of the magnet. The electrode sheet has opposite edges which extend beyond the piezo-ceramic layer and are clamped by the housing of the valve so that the center of the actuator is positioned between the seat and magnet. When an electric field is applied to the piezo-ceramic layer, the actuator bows or dishes so as to displace from the seat toward the magnet, and the magnetic field of the magnet draws the actuator further away from the seat, to increase the valve opening between the actuator and the seat.

Abstract: The spool of a fluid pressure control valve has an axial through-bore of a larger diameter at one end and a smaller diameter at the opposite end. A larger diameter pin is slidably received in the larger diameter end of the bore and a smaller diameter pin is slidably received in the smaller diameter end of the bore, and the pins are biased apart by a compression spring so as to be in abutment with the housing at both ends of the spool. Pressure from the outlet port is admitted into the through-bore of the spool between the pins so as to produce a feedback pressure force on the spool which is proportional to the value of the outlet pressure and the difference in area between the two pins.

Abstract: The invention relates to a hydraulic pumping unit for feeding the hydraulic tilting cylinder(s) of a vehicle having a tilting cab, having a housing (1), a displacement body mounted for movement in a pumping chamber within the housing (1), a control valve having a bore in connection with the pumping chamber and a control valve body (2) within the bore, the control valve body (2) being provided, at an end (3) projecting beyond said housing (1), with a handle by means of which the control valve body (2) may be turned between at least two positions operative to tilt the cab from the drive position and to tilt the cab back into the drive position of the vehicle respectively. In accordance with the invention, the handle has an inner part (A) that is fixedly connected with the control valve body, and an outer part (B) which encloses the inner part (A) in a free rotating manner and is mounted to be coupled with the inner part by means of a key-operated lock cylinder (24), the outer part (B) forming the handle.

Abstract: A hydraulic coupler has two halves connected together and identical bores in the halves which together promote laminar flow through the coupler. After entering the poppet in one half, flow through the coupler is directed to an enlarged flow section, through the central portion of the coupler to the enlarged flow section in the other half and then through crossbores in the poppet in the other half and out through that poppet. The flow section of each half is between a seating section and an outward section, and the seating section has a cylindrical portion with a diameter which is equal to the diameter of the outward section.

Abstract: A variable assist power steering system for a motor vehicle has an electronically controlled working pressure valve which normally maintains a working pressure at a relief pressure but increases it in response to steering of the vehicle and according to vehicle status, such as vehicle speed. The system also has electronically controlled direction control valves which are actuated to selectively reduce the working pressure to one side or the other of the steering gear piston so as to match a measured handwheel torque with a value which is desired for the vehicle status.

Abstract: Pump assembly, comprising a radial plunger pump for hydraulic fluid, having a pump housing with radial cylinders formed therein, in each of which cylinders a plunger is reciprocable by means of an eccentric rotor, an electric motor with a rotary output shaft which is connected for driving purposes to the rotor of the radial plunger pump, and a reservoir body for forming a reservoir for hydraulic fluid, the radial plunger pump, the electric motor and the reservoir body being interconnected to form a unit. The reservoir body and the electric motor are fitted at the same side of the pump housing, the reservoir body being adjacent to the pump housing at one side and at the opposite side having a recess. The electric motor preferably projects over a part of its length into the recess of the reservoir body. The reservoir body is preferably designed for fixing the pump assembly to a support.