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US4002956A Expired / Lapsed US ⏱️ 0.0 years remaining

Automatic electronic lock off system for an appliance

Assignee: Individual
•
Filing: 1975-06-06
•
Granted: 1977-01-11
•
Expires: 1995-06-06
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Abstract

Abstract Apparatus for the prevention of theft of electrical appliances comprises an automatic electronic lock off system which may be activated in a particular manner after the appliance is connected to a source of electrical power, and which becomes deactivated when the appliance is disconnected from its source of power to cause the further disconnection in the appliance electrical circuit. The apparatus comprises essentially three components, a key-operated activator switch, a relay, and the appliance's own on-off switch, all connected with the appliance's own circuit leads in a particular manner. The key-operated activator switch is designed to be operated with its own individual key and may, if desired, be hid from view. Initially, the key-operated activator switch is briefly closed to complete a circuit with the coil of the relay. Activation of the relay closes a normally open switch in series with the appliance on-off switch to permit the appliance then to be operable. Consequently, disconnection of the appliance from its source of power causes deactivation of the relay and opening of the normally open switch. Then, if the appliance is subsequently plugged into its source of power, the appliance circuit will be capable of being completed only when the key-operated activator switch is again closed.

Inventors

  • 👤 Ross D. Minor
  • 👤 Cleta M. Minor

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 07:34
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/14; G08B13/1409

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 152 words
An automatic electronic lock off system for an appliance comprising: an appliance, means for connecting the appliance to a source of electrical power, relay means including a coil and a normally open switch, and activator switch means, the means for connecting the appliance to a source of electrical power, the normally open switch, and the coil are connected in series, the means for connecting the appliance to a source of electrical power, the normally open switch, and the appliance are connected in series, and the means for connecting the appliance to a source of electrical power, the activator switch means, and the coil are connected in series, whereby brief closure of the activator switch means activates the relay means to close the normally open switch to permit a current flow to the appliance and to permit a current flow to the coil so that the normally open switch may be held closed.
Claim 2
Dependent Claim 152 words
An automatic electronic lock off system for an appliance comprising: an appliance, means for connecting the appliance to a source of electrical power, relay means including a coil and a normally open switch, and activator switch means, the means for connecting the appliance to a source of electrical power, the normally open switch, and the coil are connected in series, the means for connecting the appliance to a source of electrical power, the normally open switch, and the appliance are connected in series, and the means for connecting the appliance to a source of electrical power, the activator switch means, and the coil are connected in series, whereby brief closure of the activator switch means activates the relay means to close the normally open switch to permit a current flow to the appliance and to permit a current flow to the coil so that the normally open switch may be held closed.
Claim 3
Dependent Claim 42 words
An automatic electronic lock off system for an appliance as described in claim 1 wherein the normally open switch is further in series connection with an on-off switch of the appliance and in series connection with the coil of the aforesaid relay.
Claim 4
Dependent Claim 24 words
An automatic electronic lock off system for an appliance as described in claim 2 wherein the activator switch means is a key operated switch.

References Cited (Backward Citations)

US2874376A Cited
US3319128A Cited
US3425050A Cited
US3718839A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-01-11 1980-07-12 1981-01-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-01-11 1984-07-12 1985-01-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-01-11 1988-07-12 1989-01-11 $7700.00 Window Closed / Lapsed

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