| 摘要 |
A torque wrench comprising a shaft with a longitudinal axis; wherein the shaft has a lower end and an upper end, the lower end being configured to engage a fastener. A shaft cam is configured to rotate with the shaft around the longitudinal axis. A groove is defined in the shaft cam, the groove comprising a groove upper surface. A ramp is positioned within the groove at a position below the groove upper surface, wherein the ramp comprises a ramp upper surface with a first lower point, a first upper point and a surface extending along a perimeter of the shaft cam between the first lower and first upper points at an angle with respect to the longitudinal axis. The ramp upper surface is configured so that the first lower point is positioned in the direction opposite of the direction of the intended torque with respect to the first upper point. A housing surrounds the shaft and shaft cam. The wrench comprises an outer cam comprising an engaging member extending within the housing, wherein the engaging member is configured to selectively contact ramp upper surface or groove upper surface. The wrench also comprises a spring configured to apply a downward force on the outer cam, such that the outer cam tends to prevent the shaft cam from rotating when the upper surface of the ramp is in contact with the engaging member of the outer cam. A void is defined in the groove between the ramp and a side wall of the groove, the void configured to allow the engaging member to escape the groove when it is not constrained by the ramp. |
