US 5,692,575 AGranted

Reversible power wrench

AssigneeAtlas Copco Tools AB

InventorTore Gunnar Hellstrom

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Abstract

A reversible power wrench includes a housing (10), a rotation motor, and a power transmission coupling the motor to an output shaft (21), and further includes a reduction gearing (20) with first planetary gearing (28) for transferring torque in the "forward" direction of rotation and a second planetary gearing (29) for transferring torque in the "reverse" direction of rotation. The first and second planetary gearings (28, 29) have rotationally interconnected sun gears (31, 39) and a common planet wheel carrier (34). The second planetary gearing (29) includes an inner set of planet wheels (37) intermeshing with the sun gear (39) and an outer set of planet wheels (38) intermeshing with the inner set of planet wheels (37) and engageable with a ring gear (40) which is axially shiftable between an "forward" position in which it engages the planet wheels (33) of the first planetary gearing (28) only and a "reverse" position in which it engages the outer sets of planet wheels (38) of the second planetary gearing (29) only. Speed responsive centrifugal weights (46) prevent by positive locking the ring gear (40) from being shifted during operation of the power wrench.

Claims18

Dependent claims

A power wrench comprising a housing, a rotation motor, and a power transmission coupling said motor to an output shaft, wherein:

said power transmission includes a reduction gearing shiftable between alternative directions of rotation of said output shaft,
said reduction gearing comprises a first planetary gearing engagable for power transmission in a forward direction, and a second planetary gearing engagable for power transmission in a reverse direction,
said first planetary gearing includes a sun gear and planet wheels arranged to intermesh with said sun gear of said first planetary gearing,
said second planetary gearing includes a sun gear, an inner set of planet wheels arranged to intermesh with said sun gear of said second planetary gearing, and an outer set of planet wheels arranged to intermesh with said inner set of planet wheels,
said sun gear of said first planetary gearing is rotationally interconnected with said sun gear of said second planetary gearing,
said planet wheels of said first planetary gearing and said inner set and outer set of planet wheels of said second planetary gearing are journalled on a common planet wheel carrier, and
wherein said power wrench further comprises a ring gear axially shiftable in said housing between a forward position in which said ring gear engages only said planet wheels of said first planetary gearing, and a reverse position in which said ring gear engages only said outer set of planet wheels of said second planetary gearing.

4 more elements

Dependencies are inferred from the claim text.