Patent ID: 6640444
Filing Date: 2003-11-04
Classification: F02B,Y10S,Y10T

Abstract:
A portable trimmer, comprising:an internal combustion engine; a centrifugal clutch having a clutch drum; a cutter driven by power generated by said internal combustion engine and transmitted via said centrifugal clutch; a throttle valve; a manual throttle lever for controlling output power of said internal combustion engine by adjusting said throttle valve via a throttle wire; a friction member arranged opposite said clutch drum of said centrifugal clutch; a moving member connected to said friction member and moving said friction member between a braking position to be pressed against said clutch drum and a non-braking position to be spaced from said clutch drum to release the braking action; a manual release device for moving said moving member from said braking position to said non-braking position; a release restricting device for controlling activation of said manual release device; said release restricting device having a retaining device whose operation interlocks with a movement of said throttle wire which is controlled by operation of said throttle lever and maintains said release device to be restricted from being released by said release restricting device in a range which is equal to or greater than a predetermined revolution number of said internal combustion engine; and a safety device automatically making a revolution number of said internal combustion engine less than said predetermined revolution number when said friction member is kept, for a certain period of time, under said braking condition with said friction member being pressed against said clutch drum while the revolution number of said internal combustion engine is equal to or greater than said predetermined revolution number by operation of said throttle lever.