Predetermined torque release wrench

Claim 2

A torque wrench comprising: a handle; a work engaging member rotatably mounted on said handle; an arm operatively connected at one end to said work engaging member and longitudinally extending along said handle and adapted to rotate relative to said handle; a cam lever means secured by a radially fixed pivot pin to the handle for releasably restraining said arm away from rotation relative to said handle; a resilient means for urging said cam lever means towards the position of restraining said arm from rotation; said cam lever means being in point contact with said resilient means in a plane extending substantially perpendicular to the axis of said arm and through said pivot pin so as to impart a thrust on said resilient means acting generally parallel to the axis of said arm; and said arm is in sliding point contact with a surface of said cam lever means, said surfaces being shaped to provide greater leverage between said arm and cam lever once the cam lever means begin to pivot in the direction of said resilient means thereby allowing the arm to move more easily.

Claim 3

A torque wrench comprising: a hollow handle; a work engaging member rotatably mounted on said handle; an arm operatively connected at one end to said work engaging member and longitudinally extending into said handle and adapted to rotate relative to said handle; a plunger longitudinally movable in said handle and positioned opposite the other end of said arm; resilient means for urging said plunger towards said arm; cam lever means intermediate said arm and said plunger for releasably restraining said arm away from rotating relative to said handle, said camming means being substantially restrained by said handle in radial directions about a point of rotation and substantially free to rotate about said point; said cam lever means being in point contact with said resilient means in a plane extending substantially perpendicular to the axis of said arm and through said pivot pin so as to impart a thrust on said resilient means acting generally parallel to the axis of said arm; and said arm is in sliding point contact with a surface of said cam lever means, said being shaped to provide greater leverage between said arm and cam lever once the cam lever means begin to pivot in the direction of said resilient means thereby allowing the arm to move more easily.

Claim 4

A torque wrench comprising: a hollow handle; a work engaging member rotatably mounted on said handle; an arm operatively connected at one end to said work engaging member and longitudinally extending into said handle and adapted to rotate relative to said handle; a plunger longitudinally movable in said handle and positioned opposite the other end of said arm; resilient means for urging said plunger towards said arm; cam lever means intermediate said arm and said plunger for releasably restraining said arm away from rotating relative to said handle, said camming means being substantially restrained by said handle in radial directions about a point of rotation and substantially free to rotate about said point; said cam lever means being in point contact with said resilient means in a plane extending substantially perpendicular to the axis of said arm and through said pivot pin so as to impart a thrust on said resilient means acting generally parallel to the axis of said arm; and said arm is in sliding point contact with a surface of said cam lever means, said being shaped to provide greater leverage between said arm and cam lever once the cam lever means begin to pivot in the direction of said resilient means thereby allowing the arm to move more easily.

Claim 5

The torque wrench of claim 2 wherein said cam lever means comprises a cam lever secured by fixed pivot pin to said handle.

Claim 6

The torque wrench of claim 3 wherein said cam lever is pivotably rotated about a point substantially lying on a line radial to the point of contact between said plunger and said cam lever such that radial forces created by said camming of said arm against said lever are absorbed by said pivot means and circumferential forces being substantially axial in directions relative to said handle and said plunger are absorbed by said plunger.