Programmed brake for controlling the speed of a scanning carriage
US4371254A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 2, 1980 |
| Grant date | Feb 1, 1983 |
| Priority date | — |
| Expiry date | Oct 2, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/526
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention is a programmed brake for controlling the deceleration of a scanning carriage. An encoder including an electro-optic sensor mounted on a moving carriage together with a stationary grating having a plurality of unevenly spaced apertures, provides velocity data of the rate of the relative movement of the sensor and grating during flyback or scan return. In particular, the sensor detects a plurality of light pulses through each of the apertures as the sensor moves relative to the grating. The light signals are conveyed to a counter and the count is compared to a reference number representing a deceleration profile or standard number of signals desired for each aperture. If the number of light signals is less than the standard, occurring if the carriage is overspeed, a transistor driver is pulsed to activate an electromagnetic brake connected to the scanning carriage. When the scanning carriage velocity has slowed sufficiently, the brake is inactivated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.