US 4,892,013 A · Variable speed gearing in rotary electric tool

Abstract

A variable speed gearing apparatus for a rotary electric tool, including a differential gear mechanism for being mounted within a gear case, an intermediate gear and a clutch mechanism, a final planetary gear mechanism having internal gear with projections formed on the outer peripheral surface of the internal gear in the differential gear mechanism, a torque-setting cam arranged so that said projections of the internal gear of the final planetary gear mechanism are capable of being engaged with and disengaged from the torque-setting cam a first planetary gear mechanism having an internal gas, wherein the outer peripheral surface of the internal gear of the first planetary gear mechanism in the differential gear mechanism is tapered, a brake disk having a tapered surface corresponding to the tapered surface of the internal gear of the first planetary gear mechanism, the brake disk being arranged to be axially movable to be brought into pressure contact through the tapered surface of the brake disk with the tapered surface of the internal gear of the first planetary gear mechanism movably in a rotation-stopped condition, the brake disk being arranged so that it can be interlocked against axial movement with respect to the internal gear of the final planetary gear mechanism.

Claims20

Dependent claims

A variable speed gearing apparatus for a rotary electric tool, comprising a differential gear mechanism mountable within a gear case, an intermediate gear and a clutch mechanism, a final planetary gear mechanism having an internal gear with projections formed on the outer peripheral surface of said internal gear in said differential gear mechanism, a torque-setting cam arranged so that said projections of said internal gear of said final planetary gear mechanism are capable of being engaged with and disengage from said torque-setting cam, a first planetary gear mechanism having an internal gear, wherein the outer peripheral surface of said internal gear of said first planetary gear mechanism in said differential gear mechanism is tapered, a brake disk having a tapered surface corresponding to said tapered surface of said internal gear of said first planetary gear mechanism, said brake disk being arranged to be axially movable to be brought into pressure contact through said tapered surface of said brake disk with said tapered surface of said internal gear of said first planetary gear mechanism, and means for connecting said brake disk for axial movement with said internal gear of said final planetary gear mechanism.

A variable speed gearing arrangement comprising:

(a) a gear case having a longitudinal axis;
(b) an axially movable brake disk;
(c) a first planetary gear mechanism to be operably connected to a driving shaft, said first planetary gear mechanism including an internal gear having a surface which is engageable with said axially movable brake disk to maintain said internal gear against rotation during such engagement;
(d) means for biasing said brake disk against said internal gear of said first planetary gear mechanism for engagement therewith;
(e) a final planetary gear mechanism to be operably connected to an output shaft, said final planetary gear mechanism including an axially movable internal gear having an outer periphery, said movable internal gear having projections located on said outer periphery;
(f) a torque-setting cam for engagement with said internal gear of said final planetary gear mechanism by means of said projections of said internal gear of said final planetary gear mechanism to maintain said movable internal gear against axial movement;
and
(g) means for moving said brake disk in opposition to said means for biasing said brake disk, in response to movement of said movable internal gear of said final planetary gear mechanism, to separate said brake disk from said surface of said internal gear of said first planetary gear mechanism.

5 more elements

Dependencies are inferred from the claim text.

Variable speed gearing in rotary electric tool

Life of this patent

Variable speed gearing in rotary electric tool

Life of this patent

Abstract

Claims20