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:
Jun. 14, 1994
Filed:
Sep. 28, 1992
Applicant:
Inventor:
John S Yuen, Kowloon, HK;
Assignee:
John Manufacturing Limited, Kowloon, HK;
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340566 ; 340571 ;
Abstract
In a portable device sensitive to a change in movement a switch inside the device has a movable slug which increases the electrical resistance in an electrical circuit when the device is disturbed. Such increase in resistance in the electrical circuit unbalances two inputs of a Schmitt trigger to cause an output of the Schmitt trigger to switch a switching transistor to cause an oscillator to drive an output transducer to give an alarm. A feedback loop limits the period for which the alarm is given and a delay circuit prevents an alarm being given when the device is initially energized and before the two inputs of the Schmitt trigger are balanced.