Patent attributes
A dispensing gun for viscous material including a stock supporting a push rod which is advanceable along a keep in which a cartridge of a material can be mounted. The rod is advanced by means of a catch plate and a locking plate prevents the rod retreating with the catch plate. The locking plate is carried by the rod between a first and a second position so that it acts as a lost motion brake once force is removed from the trigger in one configuration of the dispensing gun, taking the dispensing force off the cartridge to prevent leaking when the trigger is not depressed. In an alternative configuration, the lost motion is reduced, for example to zero, to allow a continuous dispensing action by maintaining the pressure in the cartridge using a pumping action of the trigger.