Siren for alarm and method of making the same
US3991703A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1975 |
| Grant date | Nov 16, 1976 |
| Priority date | — |
| Expiry date | Sep 8, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49321
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A siren for an alarm adapted to be driven by a fractional horsepower motor comprising a cup-shaped rotor cooperating with a stator having rectangular perforations in a cylindrical flange, the cup-shaped rotor and the stator being both formed as stampings, the rotor having an integral base plate staked to a hub, the base plate having a plurality of shear-formed upstanding vanes of identical irregular polygonal configuration circumferentially arranged around the center of the base plate, the cylindrical wall of the rotor having rectangular perforations equal in number to the number of vanes and each vane having a perforation adjacent thereto at the identical respective location. The method of making a siren having a stator and a rotor and in which the rotor is formed by the steps of drawing a cup from sheet metal and providing a central hole in the base plate of the cup, punching rectangular perforations in the cup flange circumferentially therearound and equally spaced, shear-forming vanes in the base plate of irregular polygonal configuration to leave congruent openings in the base plate aligned with the perforation in the cup flange and with the vanes arranged normal to the base p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.