Certain embodiments described herein are directed to lock inserts that are configured to prevent removal of a key from a lock assembly comprising the lock insert when the lock assembly is in an unlocked position. The lock insert can be configured to permit removal of the key when the lock assembly is in a locked position.

A trapped key interlock system is disclosed. A pair of hollow tubular casings located one inside the other and each having a series of elongate slots are used. When the lock is in a locked condition the elongate slots are aligned as inner and outer pairs with engaging members extending through the pairs of slots is preventing rotational movement of the tubular casings relative to each other. The engaging members are biased towards this locked condition. On insertion of the correctly coded key the engaging members are caused to move against the biasing force out of engagement with the slots in the outer tubular casing thereby allowing the inner tubular casing to rotate relative to the outer tubular casing and moving the lock to an unlocked condition.

A trapped key interlock system is disclosed. A pair of hollow tubular casings located one inside the other and each having a series of elongate slots are used. When the lock is in a locked condition the elongate slots are aligned as inner and outer pairs with engaging members extending through the pairs of slots is preventing rotational movement of the tubular casings relative to each other. The engaging members are biased towards this locked condition. On insertion of the correctly coded key the engaging members are caused to move against the biasing force out of engagement with the slots in the outer tubular casing thereby allowing the inner tubular casing to rotate relative to the outer tubular casing and moving the lock to an unlocked condition.

A locking system comprising a handle mounted such that it can rotate about an operating spindle, wherein the handle can move between a locked position and an unlocked position, a hook mounted on the handle and secured in rotation therewith, wherein the hook has a throat in which a latching point of a structure is designed to engage when the handle is in the locked position. The locking system comprises a key associated with the hook and by means of which it is possible to pass from the locked position to the unlocked position of the handle, wherein the key can be removed when the handle is in the locked position and cannot be removed when the handle is in the unlocked position.

A locking system comprising a handle mounted such that it can rotate about an operating spindle, wherein the handle can move between a locked position and an unlocked position, a hook mounted on the handle and secured in rotation therewith, wherein the hook has a throat in which a latching point of a structure is designed to engage when the handle is in the locked position. The locking system comprises a key associated with the hook and by means of which it is possible to pass from the locked position to the unlocked position of the handle, wherein the key can be removed when the handle is in the locked position and cannot be removed when the handle is in the unlocked position.

A locking system comprising a handle mounted such that it can rotate about an operating spindle, wherein the handle can move between a locked position and an unlocked position, a hook mounted on the handle and secured in rotation therewith, wherein the hook has a throat in which a latching point of a structure is designed to engage when the handle is in the locked position. The locking system comprises a key associated with the hook and by means of which it is possible to pass from the locked position to the unlocked position of the handle, wherein the key can be removed when the handle is in the locked position and cannot be removed when the handle is in the unlocked position.

A locking system comprising a handle mounted such that it can rotate about an operating spindle, wherein the handle can move between a locked position and an unlocked position, a hook mounted on the handle and secured in rotation therewith, wherein the hook has a throat in which a latching point of a structure is designed to engage when the handle is in the locked position. The locking system comprises a key associated with the hook and by means of which it is possible to pass from the locked position to the unlocked position of the handle, wherein the key can be removed when the handle is in the locked position and cannot be removed when the handle is in the unlocked position.