Wrench opening engagement surface configuration
US4930378A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 6, 1989 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Dec 6, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B13/065
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A wrench of either a socket or closed-end type is disclosed as including a closed wrench opening (30, 30a, 30', 130, 130a, 130', 230, 230') having curved engagement surfaces that connect associated pairs of flat surfaces. The curved engagement surfaces engage a conventionally toleranced hexagonal fastener without any engagement thereof by the flat surfaces. In one embodiment, the wrench opening (30, 30a, 30', 230) has a "six-point" construction including six circumferentially extending flat surfaces and six pairs of angularly oriented flat surfaces. In another "twelve-point" embodiment, the wrench opening (130, 130a, 130', 230) has twelve pairs of angularly oriented flat surfaces connected by the curved engagement surfaces. Connecting surfaces of the wrench opening connect the flat surfaces in both the "six-point" and "twelve-point" versions. The curvature of the engagement surfaces preferably has a specified relationship with respect to the size of the wrench opening and with respect to the connecting surfaces which are also curved, and the preferred angularlity of the flat surfaces with respect to the wrench opening is also specified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.