Electronic torque wrench
US3970155A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 11, 1975 |
| Grant date | Jul 20, 1976 |
| Priority date | — |
| Expiry date | Jul 11, 1995 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B23/1425
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic torque wrench including a strain measuring bridge circuit disposed to measure the bending strain of the handle thereof, a NAND gate circuit connected to alternately excite the bridge according to the switching state thereof, a differential circuit connected to receive the bridge balance signal, an integrator connected to integrate a selected polarity output signal from said differential circuit, a clock-driven counter connected to be inhibited for a predetermined time interval following each time the integrating circuit output signal changes polarity providing selected binary level output signals to switch the NAND gate circuit according to the state thereof and a logical switching circuit connected to the selected binary level output signals of said counter for alternatively connecting either the output signal from the differential circuit or a fixed reference signal to the integrator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.