Gear Mechanism
AssigneeIMS Morat Sohne GmbH
InventorsBernd Enzmann, Hansjorg Maus
Life of this patent
Estimating the term…
Abstract
A conventional gear mechanism for employment in, e.g., an accumulator driven electric bore machine or electric drill, is provided with an overload coupling provided with a light-weight plastic annular gear and a separate metal cam disk or guard plate which protects the plastic annular gear from the abrasive or damaging forces occurring at the time of the torque limiting produced by the slipping of the torque overload coupling. In the present invention the plastic annular gear and guard plate are formed as a single component, namely, a plastic annular gear with an integral wear resistant cam disk, the annular gear and cam disk formed as unit of an injection molded plastic, wherein the face side of the annular gear is layered with a wear resistant material.
Claims13
Gear mechanism comprising a gear housing (4), an annular gear (3) provided inside said gear housing, a planetary gearing (1, 2, 8, 9) provided internal of said annular gear (3) for reduction of rotations between a drive shaft (23) and an output shaft (24), said annular gear (3) provided with internal teeth which are in engagement with said planetary gearing, and an overload clutch provided between said annular gear and said output shaft, said overload clutch comprised of a cam surface (5) formed on the face of said annular gear and pressure ring (6) urged against said cam surface,
- wherein said annular ring (3) is formed of a plastic material, said annular gear (3) and cam surface (5) are formed as a single component of an injection moldable plastic material, and the face side of said annular disk, which forms the cam surface (5), is covered with a wear resistant material, and
- wherein said pressure ring (6) is secured against rotation with respect to said gear housing (4), said cam surface (5) and said pressure ring (6) facing each other and having engaging means provided on facing surfaces, a spring element (18) pressing against said pressure ring (6) from a side of said pressure ring opposite the side facing said cam surface (5), said pressure ring (6) pressing against said cam surface (5), said cam surface (5) formed intimately with said annular gear (3), and said annular gear (3) pressing against a detente wall (12), such that said annular gear (3) is frictionally prevented from rotation with respect to said detente wall (12) and said pressure ring (6) until a predetermined torque loading is exceeded, and wherein upon exceeding said predetermined torque load said annular gear (3) is able to rotate with respect to said pressure ring (6) and said detente wall (12).
An accumulator driven electrical power tool comprising a gear housing (4), an annular gear (3) provided inside said gear housing, a planetary gearing (1, 2, 8, 9) provided internal of said annular gear (3) for reduction of rotations between a drive shaft (23) and an output shaft (24), said annular gear (3) provided with internal teeth which are in engagement with said planetary gearing, and an overload clutch provided between said annular gear and said output shaft, said overload clutch comprised of a cam surface (5) formed on the face of said annular gear and pressure ring (6) urged against said cam surface,
- wherein said annular ring (3) is formed of a plastic material, said annular gear (3) and cam surface (5) are formed as a single component of an injection moldable plastic material, and the face side of said annular disk, which forms the cam surface (5), is covered with a wear resistant material, and
- wherein said pressure ring (6) is secured against rotation with respect to said gear housing (4), said cam surface (5) and said pressure ring (6) facing each other and having engaging means provided on facing surfaces, a spring element (18) pressing against said pressure ring (6) from a side of said pressure ring opposite the side facing said cam surface (5), said pressure ring (6) pressing against said cam surface (5), said cam surface (5) formed intimately with said annular gear (3), and said annular gear (3) pressing against a detents wall (12), such that said annular gear (3) is frictionally prevented from rotation with respect to said detents wall (12) and said pressure ring (6) until a predetermined torque loading is exceeded, and wherein upon exceeding said predetermined torque load said annular gear (3) is able to rotate with respect to said pressure ring (6) and said detente wall (12).
Dependencies are inferred from the claim text.