1. Field of the Invention
This invention relates to a locking device having particular utility for use with an actuator. The device can be released from its locked position by the occurrence of an elevated temperature immediate the device.
2. Description of the Prior Art
Temperature released, locking mechanisms have heretofore been provided for actuators for valves. Such actuators have generally incorporated a mass of fusible material to hold the locking elements of the device in a locked position until the occurrence of an undesirably high temperature immediate the device. Because a relatively large mass of fusible material is employed in such devices, the actuator has to be exposed to the elevated temperature for a substantial time period in order for the mass of the fusible material to be sufficiently heated to cause the entire mass to melt and permit the locking device to move to an unlocked position. Moreover, such devices cannot be readily reconstructed in the field after they have once functioned in response to an elevated temperature because of the difficulty of melting and applying a relatively large mass of fusible material.
There is, therefore, a need for a fast response temperature released, locking device having particular utility when used with an actuator or other linearly operated device wherein the fusible element which holds the locking device in a locked position is of very limited size and simple configuration such that the fusible element may be readily replaced whenever it is necessary to reactivate the heat sensitive locking device after melting of the original fusible element and releasing of the latching mechanism.