US 3,942,398 AGranted

Zero torque gear head wrench

OwnerJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Allan R. McDougal +1inventors

InventorsJames C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Allan R. McDougal, Robert M. Norman

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Abstract

A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stresses to bolt-receiving structures. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear-train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

An improved gear head wrench adapted to be employed for torquing bolts seated in a threaded bore formed in a structural member and circumscribed by a spacer comprising:

A. a motor including a first housing and a selectively driven torque input shaft projected axially from said first housing;
and
B. a drive unit disposed in juxtaposition with said motor and connected thereto for torquing a selected bolt seated in a threaded bore formed in a structural member and having a concentrically related spacer characterized by a radially extended key and a face disposed in frictional engagement with the member including,
1. a second housing of a substantially cylindrical configuration rigidly affixed to said first housing in coaxial alignment with said torque input shaft and having an open end disposed in spaced relation with said first housing,
2. a sun gear concentrically related to one end of said torque input shaft, being rigidly affixed thereto and supported thereby for driven rotation about an axis coincident with the longitudinal axis of symmetry for said second housing,
3. a torque output shaft disposed within said second housing and supported for driven rotation in coaxial alignment with said torque input shaft,
4. a driving plate disposed in juxtaposed, coaxial relation with said sun gear and rigidly affixed to said torque output shaft,
5. an annular array of planetary gears mounted for rotation on said driving plate in concentric relation with said torque output shaft and in coplanar meshed relation with said sun gear,
6. an internal gear disposed in circumscribing, meshed relation with said annular array of planetary gears and rigidly affixed to said second housing,
7. coupling means affixed to said torque output shaft in spaced relation with said drive plate adapted to receive in coupled relation the head of said bolt, and
8. a receiver for said spacer including an annulus defined by the open end of said second housing concentrically related to said coupling means, including a keyway for receiving the radially extended key, whereby the housing is adapted to receive said spacer in an interlocked relationship as the coupling is caused to receive the head of said bolt.

8 more elements

Abstract

Claims1