| 摘要 |
A self-enclosed variable speed trigger switch adapted for mounting in the handle of a portable electric tool. The speed adjusting mechanism comprises a catch block movable by a stop shaft threaded therethrough with the rear end of the stop shaft abutting a wall in the trigger. Thus, the rear end of this stop shaft is placed in compression to positively take up the trigger return spring force when the lock pin is engaged on the side shoulder of the catch block. This relieves the rotary speed adjusting wheel that is coupled to the front end of the stop shaft of any tensile force and thus enables this wheel to be located in a transverse slot in the trigger so as not to interfere with the finger-engaging surface.
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