Temperature control for resistance heating element
US4243875A · kind A · utility
Inventor
Key dates
| Filing date | Nov 13, 1978 |
| Grant date | Jan 6, 1981 |
| Priority date | — |
| Expiry date | Nov 13, 1998 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K3/033
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A temperature control system for a resistance element which is heated by a power supply connected to it by a switching member, the switching member being controlled by an electronic circuit which is operative to produce alternate ON-cycles and OFF-cycles whose durations are controlled by separate time constants. The durations of these alternate cycles respectively set the higher and lower temperature limits within which the heating element temperature remains. The electronic circuitry further provides a single initial ON-cycle of greater duration which occurs only when the circuit is newly turned ON and operates to bring the resistance element up to operating temperature from ambient temperature, an indicator being provided to glow during each ON-cycle interval. The control system is illustrated for use with a soldering iron which is supportable in a cradle connected with a switch to turn OFF the system when the iron rests in the cradle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.