Temporary desensitization technique for smoke alarms
First Claim
1. An electrically powered smoke alarm device, comprising:
- a housing;
a smoke detector circuit within the housing that monitors the air proximate to the housing and that produces a sensible signal in response to detected smoke having a concentration in excess of a first level of concentration, said first level of concentration corresponding to a first sensitivity for said smoke detector;
means for connecting said smoke detector circuit to a source of electrical power; and
a control circuit that temporarily reduces the sensitivity of the smoke detector circuit to the presence of smoke such that said sensible signal is produced only when smoke is detected in a second concentration which is in excess of the first level of concentration, and that automatically restores the sensitivity of the smoke detector circuit after the expiration of a predetermined time interval so that said smoke detector circuit detects the presence of smoke in excess of said first level of concentration.
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Accused Products
Abstract
A smoke alarm having a detector circuit for detecting smoke and producing a sensible signal in response to such detected smoke is provided with a manually actuated control which cooperates with the smoke detector circuit temporarily desensitize the smoke detector circuit and later to automatically re-sensitize the smoke detector circuit after expiration of a predetermined interval. A user is thus able to desensitize the smoke detector circuit to false alarming due to lower level concentrations of smoke, such as are produced during cooking, smoking, etc., while maintaining responsiveness and protection against higher concentrations of smoke, such as would result from an actual fire condition.
26 Citations
14 Claims
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1. An electrically powered smoke alarm device, comprising:
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a housing; a smoke detector circuit within the housing that monitors the air proximate to the housing and that produces a sensible signal in response to detected smoke having a concentration in excess of a first level of concentration, said first level of concentration corresponding to a first sensitivity for said smoke detector; means for connecting said smoke detector circuit to a source of electrical power; and a control circuit that temporarily reduces the sensitivity of the smoke detector circuit to the presence of smoke such that said sensible signal is produced only when smoke is detected in a second concentration which is in excess of the first level of concentration, and that automatically restores the sensitivity of the smoke detector circuit after the expiration of a predetermined time interval so that said smoke detector circuit detects the presence of smoke in excess of said first level of concentration.
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2. An electrically powered smoke alarm, comprising:
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a housing; a smoke detector circuit mounted within said housing that monitors the concentration of smoke in the air proximate to said housing and provides a sensible output signal when said smoke concentration exceeds a selectable level of smoke concentration, said smoke detector circuit including a sensitivity adjustment input connection for adjusting the selectable level of smoke concentration at which said smoke detector circuit provides said sensible output signal; means for electrically connecting said smoke detector circuit to a source of electrical energy; a manually actuated switch electrically connected to said smoke detector circuitry; and a control circuit electrically connected to said sensitivity adjustment input connection of said smoke detector circuit and electrically connected to said manually actuated switch, said control circuit operable in a first state to provide a first input to said sensitivity adjustment input connection to cause said smoke detector circuit to have a first sensitivity and to provide said sensible output when said smoke concentration exceeds a first selectable level of concentration, said control circuit operable in a second state in response to the actuation of said switch to provide a second input to said sensitivity adjustment input connection to cause said smoke detector circuit to have a second sensitivity and to provide a sensible output when said smoke concentration exceeds a second selectable level of concentration greater than said first selectable level of concentration, said control circuit automatically returning to said first state a predetermined amount of time after the actuation of said switch to cause the sensitivity of said smoke detector circuit to return to said first sensitivity. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. In an electrically powered smoke alarm device having a smoke detector circuit that monitors the air proximate to the smoke detector circuit and that produces a predetermined sensible signal in response to detected smoke in excess of a first level of smoke concentration, corresponding to a first sensitivity for said smoke alarm device, said smoke detector circuit having a sensitivity adjustment input responsive to a selectable input condition, a method of reducing the sensitivity of said smoke detector circuit to a second sensitivity so that said smoke detector circuit produces said predetermined sensible signal only in response to a second level of smoke concentration in excess of said first level of smoke concentration, said method comprising the steps of:
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selectively initiating a timing circuit that generates a predetermined timing interval; electrically connecting a selected input condition to said sensitivity adjustment input of said smoke detector circuit during said predetermined timing interval so that the sensitivity of said smoke detector circuit is decreased to said second sensitivity during said timing interval; and electrically disconnecting said selected input condition from said sensitivity adjustment input of said smoke detector circuit at the conclusion of said predetermined timing interval so that the sensitivity of said smoke detector circuit returns to said first level of sensitivity.
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Specification