Patent ID: 8381620
Filing Date: 2013-02-26
Classification: B25B

Abstract:
1. An open wrench comprising: a body having a handle and a driving head which is connected to an end of the handle, a recess is defined through the driving head so as to define a first clamp surface and a second clamp surface on two insides thereof, a first engaging surface extending from the second clamp surface and a second engaging surface extending from the first clamp surface, an opening defined between the first and second clamp surfaces and communicating with the recess, the first clamp surface, the first engaging surface and the second engaging surface respectively having a first tangential surface, a second tangential surface and a third tangential surface, the three respective tangential surfaces located on three consecutive sides of the recess for contacting three consecutive sides of a hexagonal head of a bolt, the second clamp surface having a most protruding portion which has a fourth surface which is parallel to the first tangential surface, the driving head having a passage defined therethrough; a movable member movably received in the passage and having an extension extending from an end thereof, a diameter of the extension being smaller than a diameter of the movable member so as to define a first shoulder at a conjunction portion between the movable member and the extension, the extension having an enlarged block at a distal end thereof so as to define a second shoulder at the conjunction portion between the block and the movable member; a spring mounted to the extension of the movable member and biased between the first shoulder and a clip engaged with an annular groove in the passage so as to provide a force to push the movable member toward the recess, and the movable member having a spherical distal end which protrudes from the second clamp surface, an angle defined between an axis of the passage and the fourth surface, a range of the angle being between 15 degrees to 25 degrees, an inner periphery of the clip protruding into the passage and engaged with the second shoulder to prevent the movable member from dropping from the passage.