Motor-driven hand tool with braking torque device
First Claim
1. Motor driven hand tool, such as a drill, hammer drill, grinder or the like, comprising a housing, a drive motor located within said housing, a driven shaft located within said housing, means within said housing extending between said drive motor and said driven shaft for rotating said shaft, said driven shaft projecting out of said housing and arranged to hold and rotate a bit, an inert mass rotatably supported in said housing and disposed coaxial with said driven shaft, a spring element connecting said inert mass to said housing, wherein the improvement comprises that said inert mass is annular and encircles said driven shaft, said spring element encircles said driven shaft and is displaceable from a first condition in spaced relation to said driven shaft to a second condition in gripping engagement with said driven shaft for exerting a braking action on said shaft in the event of rotation of said housing relative to said inert mass.
1 Assignment
0 Petitions
Accused Products
Abstract
In a motor-driven hand tool, such as a drill, an inert mass is rotatably supported in a housing and is connected to the housing by a spring encircling a driven shaft mounted in the housing. The driven shaft is arranged to rotate a drill bit secured to the shaft. If the driven shaft is prevented from rotating and the housing rotates relative to the shaft, the spring tightens about and grips the driven shaft exerting a braking torque on it. The braking torque reduces the reaction torque required of the tool operator and affords a more rapid release of an overload clutch acting on the driven shaft. The overload clutch is formed by a collar, a gear wheel, a cup spring, and an adjustable ring nut, all located on the driven shaft.
55 Citations
6 Claims
- 1. Motor driven hand tool, such as a drill, hammer drill, grinder or the like, comprising a housing, a drive motor located within said housing, a driven shaft located within said housing, means within said housing extending between said drive motor and said driven shaft for rotating said shaft, said driven shaft projecting out of said housing and arranged to hold and rotate a bit, an inert mass rotatably supported in said housing and disposed coaxial with said driven shaft, a spring element connecting said inert mass to said housing, wherein the improvement comprises that said inert mass is annular and encircles said driven shaft, said spring element encircles said driven shaft and is displaceable from a first condition in spaced relation to said driven shaft to a second condition in gripping engagement with said driven shaft for exerting a braking action on said shaft in the event of rotation of said housing relative to said inert mass.
Specification