Electromyographic repetitive strain injury monitor
US4807642A · kind A · utility
Inventor
Key dates
| Filing date | Apr 10, 1987 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Apr 10, 2007 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/389
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A monitoring device for detecting muscle strain, which might lead to repetitive strain injury includes EMG sensors which generate an EMG signal, signal processing circuitry to derive a signal or signals representative of undesirable strain conditions and an acoustic signal generator which produces a signal to indicate when undesirable strain conditions exist. The signal processor includes a band pass filter to band limit the EMG signal, a rectifier and low pass filter to produce an envelope signal and a minimum signal level tracking circuit comprising amplifiers, capacitor, diodes and resistors. The minimum signal level tracking circuit produces a minimum level signal which tracks the envelope signal, with a short time constant while the minimum level signal is greater than the envelope signal, and with a long time constant when the minimum level signal is less than the envelope signal. The acoustic signal generator produces an acoustic alarm signal when the minimum level signal exceeds a preset threshold level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.