Abstract: A pin locking mechanism selectively permits or resists the rotation of two nested tubular members with respect to each other. The pin has a substantially rectangular cross-section. The pin passes through a pair of holes defined in the outer tubular member, and a pair of slots defined within the inner tubular member. The slots have ends wider than their central portion, so that the pin may only fit within the central portion of the slot when it is substantially parallel to the slot, but may fit within the end portions when it is perpendicular to the slot. The nested tubular members may therefore be rotated with respect to each other when the pin is held substantially parallel with the slot, and rotation is resisted when the pin is held in a perpendicular orientation. A handle at one end of the pin is biased towards the outer tubular member by a spring at the opposite end of the pin.

Abstract: A crowd control barrier including a frame and a base rotatably mounted to the frame and lockable in at least a first position and a second position. The crowd control barrier also includes a pin for securing the base to the frame, the pin being in a first locked position when the base and the frame are locked in the first position, the pin then being rotated into a second locked position so that the base can rotate to the second position, and the pin then being rotated again back to the first locked position when the base and the frame are locked in the second position.