Impact wrench having an improved anvil to square driver transition

1. An anvil for use with a tool, the anvil comprising:

a round body;

a generally square head formed at an end of the round body adapted to receive an accessory thereon, the head including a generally tapered transition into the round body;

reliefs formed in corner portions of the generally square head; and

stops formed on the tapered transition, the stops in alignment with the reliefs such that the stops are adapted to abut the accessory when the accessory extends over the reliefs.

2. The anvil of claim 1 , wherein the reliefs are shaped as concave portions.

3. The anvil of claim 1 , wherein the square head and round body define a longitudinal axis, and the square head includes a roll pin hole adapted to receive a roll pin, the roll pin hole extending into the square head substantially perpendicular to the longitudinal axis of the round body.

4. The anvil of claim 1 , wherein the generally square head includes angled faces formed at intersections of sides of the square head.

5. The anvil of claim 4 , wherein the reliefs are formed in the angled faces.

6. A tool comprising:

a housing;

a motor mounted within the housing; and

an anvil driven by the motor, the anvil including a round body and a square head formed at an end of the round body, the square head including a generally tapered transition into the round body, a stop formed on the tapered transition, and a relief formed on at least one corner of the square head proximate the tapered transition.

7. The impact wrench of claim 6 , wherein the stop is approximately ramp shaped and is adapted to abut a portion of an accessory coupled to the anvil.

8. The impact wrench of claim 6 , wherein the square head and round body define a longitudinal axis, and the square head includes a roll pin hole adapted to receive a roll pin, the roll pin hole extending into the square head perpendicular to the longitudinal axis of the round body.

9. An anvil and accessory for use with an impact wrench, the anvil and accessory comprising:

an anvil having a round body and a generally square head formed at an end of the round body, the generally square head including a plurality of reliefs formed in the corners thereof and a generally tapered transition into the round body, the generally tapered transition including a stop formed thereon;

an accessory adapted to engage the square head, the accessory, when fully assembled, having a portion thereof overlapping said reliefs on the square head.

10. The anvil and accessory of claim 9 , wherein the accessory abuts the stop when engaged with the anvil such that a portion of the accessory overlaps a portion of the reliefs.

11. The anvil and accessory of claim 9 , wherein the reliefs are concave.

12. The anvil and accessory of claim 9 , further comprising a détente pin hole formed in a side of the generally square drive head.