The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 10, 1990
Filed:
Feb. 27, 1989
Kevin L Bailey, Rolling Meadows, IL (US);
Rixson-Firemark Inc., Franklin Park, IL (US);
Abstract
An electromagnetic lock including an armature and an electromagnet with the armature adapted for floating attachment to a door by a plunger-bolt assembly fixed to the door, and an electromagnet adapted for fixed attachment to a door frame. A door-movement alert switch structure comprising a pushbutton switch supported on the electromagnet, a plunger supported on the plunger-bolt assembly, and a spring force-biasing the plunger into mating contact with the switch when the door is electromagnetically locked to establish a first switch-actuation state. The force-biased spring maintains the switch in its first state while the armature is magnetically restrained. When the door is opened a door-movement distance slightly less than the armature float distance, the plunger is partially drawn into a plunger housing fixed on the plunger-bolt assembly. The switch responds by transferring to a second switch actuation state indicating an attempt to open the magnetically locked door.