about the pivot 50 if no object is present to stop the rotation of the shackle bracelet 46 the ratchet teeth 48 by engagement with the pawl restrict the counter rotation of the shackle bracelet 46 in the opening direction opposite to that of the closing direction to release an object which has been shackled by the handcuff 10 a lock release mechanism disengages the one way pawl from the ratchet teeth 48 releasing the shackle bracelet 46 to rotate in the opening direction thereby expanding the opening between the shackle base 44 and the shackle bracelet 46 when the last ratchet 48 clears the pawl the shackle extension 46 is free to rotate about pivot 50 and opening the bracelet permits removal of the restrained object e g wrist from the handcuffs 10 the locking mechanism for release of the pawl includes a standard lock and key mechanism to which keyhole 20 provides access the keyhole 20 shown in a detailed view in fig2 normally comprises a rounded portion 21 for receiving a shaft of a key not shown in this view and a slot portion 24 for receiving the key spline such as spline 14 fig3 which extends radially from the shaft a spline 14 is normally a flattened key spline attached to one end of the shaft 12 of the key 25 fig3 the detail view of keyhole 20 fig2 further illustrates a standard orientation pin 22 which is centrally disposed in the keyhole rounded portion 21 and is attached to an inner wall.