Patent ID: 8973474
Filing Date: 2015-03-10
Classification: B25B

Abstract:
1. A screwdriver bit structure having auxiliary positioning function comprising: a screwdriver bit having a front driving portion, a rear fitting portion, a circular cylinder extended between said driving portion and said fitting portion, and a concave ring groove formed between said driving portion and said circular cylinder, wherein said fitting portion of said circular cylinder is a polygon shaft body; and an auxiliary sheath which is a tube body being securely fastened at said screwdriver bit in a rotatably movable manner to prevent said auxiliary sheath from offsetting and coming off said screwdriver bit while rotating said screwdriver bit, wherein said auxiliary sheath comprises an elongated tube body which has a tube hole and a protruding ring integrally extended from an internal wall of said tube hole to define a long inserting portion and a short inserting portion, wherein a length of said long inserting portion is larger than a length of said short inserting portion, wherein an internal diameter of said tube hole is slightly greater than an external diameter of said circular cylinder to fit said circular cylinder with said tube hole, such that said internal diameter of said tube hole at said long inserting portion equals to said internal diameter of said tube hole at said short inserting portion which is slightly greater than said external diameter of said circular cylinder, wherein an internal diameter of said long inserting portion is larger than an internal diameter of said protruding ring, wherein an internal diameter of said short inserting portion is larger than the internal diameter of said protruding ring, wherein said protruding ring fits in said concave ring groove such that a length of said protruding ring matches with a length of said concave ring groove, wherein said auxiliary sheath is fitted to said concave ring groove in such a manner that said protruding ring of said auxiliary sheath is rotatably coupled within said concave ring groove to prevent said auxiliary sheath being detached from said front driving portion of said screwdriver bit, said long inserting portion covers and rotatably extends at a periphery of said front driving portion to expose a driving head of said driving portion out of said long inserting portion, and said short inserting portion covers a periphery of said circular cylinder, so as to allow said screwdriver bit freely rotating in said tube hole of said auxiliary sheath and prevent forward and backward sliding movements along a length of said auxiliary sheath.