Padlock

A padlock comprising:

• (a) a lock body defining an interior cavity;
• (b) a shackle releasably lockable to the body in a closed position defining a closed space between the shackle and the body for securing to an object, and movable to an open position for receiving and releasing the object between the shackle and the body;
• (c) a primary lock disposed in the interior cavity and selectively lockable and unlockable;
• wherein the lock body is made of a material of sufficient strength for shielding the interior cavity;
• (d) a drive linkage associated with the primary lock and the shackle for restricting movement of the shackle relative to the lock body from the open position to the closed position when the primary lock is locked, and for driving the shackle between the open and closed position when the primary lock is unlocked;
• and
• (e) a secondary lock operatively engageable with the shackle in a locked position for restricting movement of the shackle from the closed towards the open position;
• wherein the drive linkage has a first strength to resist a first predetermined force biasing the shackle form the closed position towards the open position mid the primary lock has a second strength, the first strength being less than the second strength such that the drive linkage fails upon application of a force greater than the predetermined force with the primary lock remaining intact.