Image Number 3 for United States Patent #4787275.
An adjustable double-ended box wrench (10,10') is disclosed as including a wrench body (12) defining large and small box wrenches (20,22), an adjustable jaw assembly (14,14') including an elongated adjusting member (54,54') and a rotatable adjuster (56) that moves jaw end surfaces (70,72) to adjust the sizes of the wrenches, and a cover plate (16) that is secured to the wrench body (12) to retain the adjustable jaw assembly (14,14'). Each of the large and small box wrenches (20,22) includes a pair of associated diverging portions (34,44) and a pair of converging portions (36,46) as well as an associated connecting portion (42,52) that connect the associated engagement portions. Each of the connecting portions (42,52) preferably has a connecting wall (76,78) with curved ends that are tangent to associated engagement surfaces (38,48) in order to prevent stress concentration during use. In one embodiment of the wrench (10), the rotatable adjuster (56) is comprised by an adjusting nut ( 97) that receives an externally threaded portion (62) of the associated adjusting member (54) to provide the adjustment. In another embodiment of the wrench (10'), the rotatable adjuster (56) is comprised by an adjusting screw (110) that receives an internally threaded portion (106) of the associated adjusting member (54') to provide the adjustment. In each embodiment, the spacing between jaw ends (70 and 72) provides ease in switching from one wrench end to the other.