Patent ID: 7406895

Claim:
A socket comprising: a coupling end adapted to be coupled with and driven by a driving tool; and a driving end adapted to engage with a fastener to be driven, with the driving end comprising a peripheral wall portion having six inner faces on an inner periphery thereof for coupling with and driving the fastener, with a recessed portion being formed between a pair of inner faces adjacent to each other, with the peripheral wall portion further comprising six concave outer faces on an outer periphery thereof and respectively opposite to the inner faces, with a convex gripping portion being formed between a pair of concave outer faces adjacent to each other, and with the concave outer faces and the convex gripping portions forming a non-smooth outer periphery of the peripheral wall portion; with the peripheral wall portion further including a ridge-shaped end edge formed between each said concave outer face and one of the convex gripping portions adjacent to the concave outer face, with the ridge-shaped end edge being adapted to provide a user's hand holding the socket with friction, with a first thickness being defined between an intermediate portion of one of the inner faces and an intermediate portion of one of the concave outer faces opposite to the inner face, with a second thickness being defined between an intermediate portion of one of the recessed portions and an intermediate portion of one of the convex gripping portions opposite to the recessed portion, with a third thickness being defined between one of the ridge-shaped end edges and an end of one of the recessed portions opposite to the ridge-shaped end edge, with the first thickness being substantially the same as the second thickness, with the second thickness being substantially the same as the third thickness, with the socket having an outer radius of a first circle that has a first center, with each concave outer face being an arc of a second circle having a second center and a radius, with a distance between the first and second centers being smaller than a sum of the outer radius of the socket and the second radius of the second circle, with a ratio of the radius of the second circle to the outer radius of the first circle being in a range between 2.01:1 and 5.08:1, and with a ratio of the distance between the first and second centers to the outer radius of the first circle being in a range between 2.91:1 and 6.01:1.