Abstract: A suspension unit, for example for a track-laying vehicle, comprises an oil-filled cylinder within which a piston, connected to a piston rod, is provided. The cylinder 4 is oil-filled, and communicates with an upper region of a spring chamber, the lower region 46 of which contains gas under pressure. The piston rod has a hollow interior filled with gas under pressure. The piston is connected by a connecting rod to a secondary piston which is slidable within the piston rod. On rebound the piston rod and the piston move relatively to each other between a retracted end position and an extended end position. During this movement and the return movement, oil is transferred, by way of apertures between damping chambers which serve to damp the relative movement of the piston and the piston rod so avoiding shock loading at the end positions of the movement.

Abstract: A suspension unit comprises a hub about which a suspension arm is pivotable. The hub is secured to a vehicle chassis or hull by means of a connecting element. The connecting element has a flange provided with holes positioned to coincide with pre-existing holes on the vehicle hole or chassis. The suspension unit can thus be retro-fitted to a vehicle in place of an existing suspension unit of a different kind.

Abstract: A suspension unit comprises a hub about which a suspension arm is pivotable. The hub is secured to a vehicle chassis or hull by means of a connecting element. The connecting element has a flange provided with holes positioned to coincide with pre-existing holes on the vehicle hole or chassis. The suspension unit can thus be retro-fitted to a vehicle in place of an existing suspension unit of a different kind.

Abstract: A suspension unit, for example for a track-laying vehicle, comprises an oil-filled cylinder within which a piston, connected to a piston rod, is provided. The cylinder 4 is oil-filled, and communicates with an upper region of a spring chamber, the lower region 46 of which contains gas under pressure. The piston rod has a hollow interior filled with gas under pressure. The piston is connected by a connecting rod to a secondary piston which is slidable within the piston rod. On rebound the piston rod and the piston move relatively to each other between a retracted end position and an extended end position. During this movement and the return movement, oil is transferred, by way of apertures between damping chambers which serve to damp the relative movement of the piston and the piston rod so avoiding shock loading at the end positions of the movement.

Abstract: The in-situ robotic testing system uses a robotic probe positioning apparatus, attached to the system under test, to position the probe head and its associated probe tip at a selected location on the printed circuit board under test. Access to the printed circuit board under test is facilitated by the removal of the printed circuit board in the adjacent slot in the card cage. The robotic probe positioning apparatus comprise motors and associated control software. The control software can process user input and direct the motors to place the probe tip. The control software also directs the probe to perform the testing and provides the test results to the user. X-axis, Y-axis and Z-axis motors are used to control the linear movement of the probe head and two rotational motors control the position and orientation of the probe tip relative to the circuitry and engage the probe tip with the particular circuit trace on the printed circuit board.