Combustion products detector with accelerated test
First Claim
1. In a combustion products detector including combustion products sensing means, alarm means responsive to the sensing of combustion products by the sensing means, control means for periodically enabling the sensing means and test means selectively operable for simulating the presence of combustion products, the improvement comprising:
- frequency change means coupled to the control means and responsive to operation of the test means for changing the frequency of enablement of the sensing means.
3 Assignments
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Accused Products
Abstract
A battery-powered photoelectric smoke detector periodically samples the air in a smoke chamber. A manually-operated test button is provided for simulating smoke to test the device. The sampling frequency is determined by a first resistance. A frequency changing circuit includes a test switch, the movable contact of which is coupled to the test button and is responsive to operation thereof for connecting it parallel with the first resistance the series combination of a diode and a second resistance for increasing the sampling frequency. Means are provided for back-biasing the diode to disable the frequency changing circuit when the detector detects smoke.
52 Citations
20 Claims
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1. In a combustion products detector including combustion products sensing means, alarm means responsive to the sensing of combustion products by the sensing means, control means for periodically enabling the sensing means and test means selectively operable for simulating the presence of combustion products, the improvement comprising:
- frequency change means coupled to the control means and responsive to operation of the test means for changing the frequency of enablement of the sensing means.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a combustion products detector including combustion products sensing means, alarm means responsive to the sensing of combustion products by the sensing means, control means for periodically enabling the sensing means at a low first frequency during standby and at a higher second frequency in response to sensing of combustion products by the sensing means, and test means selectively operable for simulating the presence of combustion products, the improvement comprising:
- frequency change means coupled to the control means and responsive to operation of the test means for changing the frequency of enablement of the sensing means to a third frequency, and means coupled to the control means and to said frequency change means for disabling said frequency change means in response to the sensing of combustion products by the sensing means.
- View Dependent Claims (11, 12, 13, 14)
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15. In a combustion products detector including combustion products sensing means, alarm means responsive to the sensing of combustion products by the sensing means, control means for periodically enabling the sensing means and test means selectively movable between a normal condition and a test condition for simulating the presence of combustion products, the improvement comprising:
- first impedance means coupled to the control means so that the frequency of enablement of the sensing means is a function of the impedance of said first impedance means, second impedance means, and switch means coupled to said first and second impedance means and to the test means and responsive to movement of the test means to its test condition for connecting said first and second impedance means in parallel.
- View Dependent Claims (16, 17, 18, 19, 20)
Specification