Torque wrenches
US4854197A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 20, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | Jan 20, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B21/005
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The double-acting piston of a torque wrench has a piston rod, the free end of which receives a pin which is guided at each end in straight or curved guide channels in the wrench housing. The pin passes through drive shoes which are slidably received in slots at the upper end of a drive lever. As it reciprocates, the driver lever rotates a ratchet wheel, the ratchet wheel having a square central bore to receive a square drive shaft journaled in the housing. If the constant force is applied, the torque wrench provides a substantially constant torque, particularly if the guide channels are curved to compensate for frictional losses. The ratchet mechanism includes rollers which float between grooves in the ratchet wheel and sockets in the drive lever.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.