초록 ▼

The chain of an electromotive chain saw is quickly stopped by the combined use of an electric brake and a mechanical brake when a trigger member is turned off. The rear end of a brake band disposed to tighten a brake drum by operating a hand guard is secured to a bent rod. When the trigger member is

The chain of an electromotive chain saw is quickly stopped by the combined use of an electric brake and a mechanical brake when a trigger member is turned off. The rear end of a brake band disposed to tighten a brake drum by operating a hand guard is secured to a bent rod. When the trigger member is released, the brake band is normally tightened around the outer periphery of a brake drum by the urging force of a coil spring. When the trigger member is released, a circuit provided with a brake winding is closed, thereby applying a dynamic braking force. When the dynamic brake force is applied, a centrifugal clutch is released quickly and the speed of stopping the brake drum is accelerated.

대표청구항 ▼

[ What is claimed is:] [1.] An electromotive chain saw comprising;a guide bar having a track extending around a periphery thereof;a cutting chain being supported by said track of said guide bar and being rotatable therearound;an electric motor, having an armature, being drivingly-connected to said c

[ What is claimed is:] [1.] An electromotive chain saw comprising;a guide bar having a track extending around a periphery thereof;a cutting chain being supported by said track of said guide bar and being rotatable therearound;an electric motor, having an armature, being drivingly-connected to said cutting chain, via a drive mechanism, to rotate said cutting chain about the periphery of said bar along said track, and said drive mechanism including a brake drum drivingly connected to said cutting chain for rotation with said cutting chain;a mechanical brake being arranged to engage with said brake drum, said mechanical brake having a disengaged position in which said mechanical brake is disengaged from said brake drum and permits rotation thereof, and said mechanical brake having an engaged position in which said mechanical brake engages with said brake drum and exerts a braking force on a surface of said brake drum to stop the rotation of thereof and, in turn, stop rotation of said cutting chain rotated thereby;a dynamic brake circuit being electrically coupled to said armature of said electric motor to supply power thereto and rotate said cutting chain, in an operation position of said dynamic brake circuit, and said dynamic brake circuit having a braking position in which said dynamic brake circuit applies a braking force to said armature of said electric motor to stop rotation thereof; anda common trigger member being directly linked to both said dynamic brake circuit and said mechanical brake such that actuation of said common trigger member to an ON position concurrently actuates both said mechanical brake to said disengaged position and said dynamic brake circuit to said operation position while actuation of said common trigger member to an OFF position concurrently actuates both said mechanical brake to said engaged position and said dynamic brake circuit to said braking position whereby both said dynamic brake force on said armature of said electric motor and said braking force on said brake drum are concurrently applied.