Piezoresistive elevator button
US5040640A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Jul 19, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/964
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A piezoresistive elevator button assembly comprises a polymer film piezoresistive element sandwiched between a button and a button pressure plate, and circuitry for sensing a change in the resistance of the piezoresistive element. The piezoresistive element is held in place by a high temperature potting compound to create a button less sensitive to fire or heat. A compensating spring is placed between the piezoresistive element and the buttom pressure plate to eliminate the effect on that element due to temperature cycling of the button assembly elements. A frustoconical housing of the button employing catch teeth allows for little movement; the use of the polymer film piezoresistive element allows a signal to be generated though buttom movement is nearly imperceptible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.