Abstract: A coupling device comprises a generally u-shaped member with a base 11 and two arms 12, 13, and retaining means at each arm for accommodating and retaining a respective cylindrical pin 30. One of the retaining means comprises an integral hook 14 extending from the inside of the arm 12 towards the other arm 11 and has a tip 15 which projects towards the base 11. The hook is sufficiently resilient to permit the tip 15 to be manually deflected away from the base 11 to permit a pin 30 of greater diameter than the distance between the tip and the base in the undeflected state of the hook to be inserted under the hook. The pin is retained between the hook and the base by releasing the hook and permitting it to assume its undeflected state.