Steering column assembly

Abstract

A steering column assembly comprises a telescopic shroud having an outer shroud portion and an inner shroud portion, a clamp rail fixed to the inner shroud portion including a slot that extends axially along the inner shroud portion, a clamp bolt that extends perpendicular to the shroud that may be rotated around its long axis by operation of a locking lever, and a toothed block that is connected to the clamp bolt having a row of teeth on each side, the pitch between teeth of each row being equal to, or a whole multiple of, the pitch of the teeth of a corresponding row of the slot. The toothed block is supported by a carrier that moves in response to rotation of the clamp bolt to in turn move the toothed block between a clamped position and an unclamped position and supports the toothed block such that the toothed block is free to move from side to side when in the slot. The teeth of a first row of the slot and the corresponding teeth of the toothed block when in flank to flank contact prevent axial movement of the toothed block along the slot in a direction corresponding to a telescopic collapse of the shroud and in that the teeth of a second row of the slot and the corresponding teeth of the toothed block permit axial movement of the toothed block along the slot in a direction corresponding to a collapse of the shroud whilst applying a thrust to the toothed block that moves the toothed block sideways across the slot so that the flanks of the teeth of the first row face the flanks of the corresponding teeth of the toothed block.