US Patent 7004520 Locking arrangement for engagement tool

A locking mechanism for elongate tools that are designed to engage objects from remote distances and that have engagement elements located on a distal end of a rod, a handle on a proximate end of the rod, a controller on the handle to control the engagement elements, and a linkage between the controller and the engagement elements to control the engagement elements is disclosed. The locking elements include a saw tooth receiving surface that is rigidly affixed to a trigger and a stop member having complementary saw tooth extensions. A switch member controls the movement of the stop member into engagement and out of engagement with the receiving surface which thereby locks and unlocks the movement of the trigger.