Abstract: An automatic brake control for rotary electric tools such as saws, drills, sanders, grinders and the like comprises a pair of spring biased brake shoes positioned about the periphery of the brake drum of an electric motor which drives the tools. The brake shoes are normally spring biased into engagement with the brake drum which is placed around the fan which in turn is pressed onto the armature shaft. Upon actuation of the motor, a cam element moves the brake shoes back from the drum and into an anchor recess at one end, permitting the motor to operate the tool. The cam element is actuated by a linkage coupled to the trigger through an intermediate pivot plate. When pressure is released on the trigger, the brake shoe springs take over snapping the shoes into contact with the drum and moving the linkage back to the starting position. This action immediately stops the tool and eliminates possible safety problems.

Abstract: A brake control for rotary electric tools, particularly hand tools, comprises a pair of spring biased brake shoes positioned about the periphery of the armature of an electric motor which drives the electric tool. The brake shoes are normally spring biased into engagement with a brake drum coupled to the armature, but upon actuation of the motor a cam element moves the brake shoes back from the drum permitting the motor to operate the tool. The cam element is actuated by a solenoid preferably located in the handle of the tool and operated by the trigger mechanism. When pressure is released on the trigger, the solenoid actuates the cam through a suitable linkage causing the brake shoes to engage the brake drum on the armature thereby immediately stopping the tool and eliminating possible safety problems.