Steering column assembly

A steering column assembly comprising a steering column shroud which supports a steering shaft for a steering wheel, the column shroud comprising an inner tubular member and an outer tubular member, the inner tubular member being at least partially received within the outer tubular member, a support bracket which is fixed in position relative to a part of the vehicle, the outer tubular member passing between two spaced apart arms of the bracket, and a clamp assembly which includes a cam mechanism, and in which the clamp assembly includes a clamp pin which passes through openings in each of the two arms of the bracket, the clamp pin being provided with a first reaction member located towards one end of the clamp pin outside of one arm of the support bracket and a second reaction member located towards the other end of the clamp pin outside of the other arm of the support bracket such that the arms of the support bracket are located on the clamp pin between the reaction members and with the cam assembly located between the outside of one arm and one of the reaction members,

• in which the clamp mechanism comprises a fixed cam portion and a moving cam portion, the clamp mechanism being movable between a locked position in which the overall length of the cam mechanism is such that the arms of the support bracket are squeezed together causing an elongate slot in the outer tubular member to at least partially close up and thereby causing the outer tube to clamp onto the inner tubular member, and an unlocked position in which the overall length of the cam mechanism is shorter so that the arms of the clamp bracket are free to move apart, allowing the elongate slot to open and thereby releasing the grip of the outer tubular member on the inner tubular member,
• wherein the fixed cam portion is mechanically connected to the support bracket such that at least during an initial release phase of the clamp assembly the force required to produce a rotational movement of the fixed cam portion relative to the support bracket exceeds any rotational force exerted on the fixed part due to strain energy stored in the assembly that would otherwise cause the fixed cam portion to rotate, and in which the support bracket has an inverted U-shape, having a base from which vertical arms depend with at least one vertical arm may have an inner and an outer leaf, the fixed cam part being mechanically connected to the inner leaf when the clamp assembly is locked and in which the fixed cam portion passes through an elongate slot in the support bracket allowing the fixed cam portion and clamp pin to move relative to the support bracket to provide adjustment for rake of the steering assembly.