Abstract: A locking device to engage with an upper end of a lower elongate member and a lower end of an upper elongate member wherein the upper and lower elongate members are telescopically engaged. The locking device is operable in a disengaged position to frictionally hold the position of the lower elongate member relative to the upper elongate member. In the disengaged position, the locking device prevents retraction of the lower elongate member relative to the upper elongate member but enables extension of the lower elongate member relative to the upper elongate member. If a compressive force is applied to retract the lower elongate member within the upper elongate member, then the locking device grips the lower elongate member with more force to prevent retraction of the lower elongate member within the upper elongate member when the locking device is in the disengaged position.