US 4,206,658 AGranted

Rotary ratchet mechanism

AssigneeBowmar Instrument Corporation

InventorRobert W. Herr

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Abstract

Rotary ratchet mechanism includes a ratchet wheel rotating about a first axis. A dog at one end of a lever engages a tooth of a wheel to rotate it in one direction. The lever is pivoted to a member at a point spaced from its end, the member being movable from first to second positions along a second axis spaced from the first axis and normal to a plane including the same to move the dog in the opposite direction from a first position engaging one tooth to a second position engaging another tooth. The pivot is spaced from the second axis on its side remote from the first axis and in the first position of the member is spaced from the other side of the plane. An anti-reversing dog is provided at one end of a second layer pivoted to a support at a second point spaced from its end, the second pivot being spaced from the other side of the plane and from the second axis on its side toward the first axis. Spring means acts on both levers to bias the first lever to urge the dog into engagement with a tooth, to bias the second lever in a direction to urge the anti-reverse dog into engagement with a driving portion of a tooth, and to return the member to its first position thereby to return the first lever and dog to the first position to rotate the wheel in one direction.

In a rotary ratchet mechanism including a toothed ratchet wheel mounted on a support member for rotation about a first axis, each tooth of said wheel having a driving portion and an inclined portion, a driving dog at one end of a lever member and adapted to engage a driving portion of a said tooth thereby to rotate said wheel in one direction, said lever member being pivotally connected to a pivot member at a point spaced from said one end, said pivot member being linearly movable from a first position to a second position along a second axis spaced from said first axis and normal to a plane including said first axis thereby to move said driving dog in a direction opposite said one direction from a first position with said driving dog engaging the driving portion of one tooth to a second position engaging the driving portion of another tooth, spring means for returning said pivot member to said first position thereof thereby to return said lever member and driving dog from said second positions to said first positions to rotate said wheel in said one direction by a predetermined incremental amount, and an anti-reversing dog adapted to engage the driving portion of one tooth thereby to prevent rotation of said wheel in the opposite direction;

the improvement wherein said pivot point in said first position of said pivot member is spaced from said second axis on the side thereof remote from said first axis, said anti-reversing dog being at one end of a second lever member pivotally connected to said support member at a second point spaced from said one end thereof, said second pivot point being spaced from the other side of said plane and spaced from said second axis on the side thereof toward said first axis, said spring means comprising a single spring acting on said pivot member and both said lever members thereby to bias said driving dog into engagement with a driving portion of a said tooth and to bias said second lever member in a direction to urge said anti-reversing dog into engagement with a driving portion of a said tooth.

Abstract

Claims10