Abstract: A trailer tandem wheel suspension system comprising a pair of suspension units (3) for mounting on either side of a chassis (4) of a trailer (1) to support a pair of wheels 2?, 2? and arranged to respond both to small and large deflections of the wheels 2?, 2?. Each suspension unit (3) has a primary spring element (12) and a secondary spring element (13) linked to the primary spring element (12) so that the primary and secondary spring elements (12, 13) are effective over different ranges of movement of the wheels 2?, 2?. The primary spring element (12) is a leaf spring responsive to small movements of the wheels 2?, 2? and the secondary spring element (13) includes a compression spring (18) linked to the leaf spring and responsive to larger movements of the wheels 2?, 2?.

Abstract: A mobile barrier system comprises a wheeled trailer and a barrier mounted on the trailer. The barrier comprises a series of panels configured to form walls of the trailer in a collapsed condition for transportation of the barrier. The panels are movable to an erected condition for assembly of the barrier in which the panels are substantially aligned to form the barrier. One or more panels may be adjustable to vary the width of the barrier and two or more barrier systems may be linked to form a wider barrier. Stabilisers are provided to resist movement of the barrier in the erected condition. Guard panels at the top of the barrier can be deployed to resist scaling of the barrier by individuals and/or to increase the height of the barrier.

Abstract: A trailer tandem wheel suspension system comprising a pair of suspension units (3) for mounting on either side of a chassis (4) of a trailer (1) to support a pair of wheels 2?, 2? and arranged to respond both to small and large deflections of the wheels 2?, 2?. Each suspension unit (3) has a primary spring element (12) and a secondary spring element (13) linked to the primary spring element (12) so that the primary and secondary spring elements (12, 13) are effective over different ranges of movement of the wheels 2?, 2?. The primary spring element (12) is a leaf spring responsive to small movements of the wheels 2?, 2? and the secondary spring element (13) includes a compression spring (18) linked to the leaf spring and responsive to larger movements of the wheels 2?, 2?.