AUTOMATIC CONTROL OF VENETIAN BLINDS IN RESPONSE TO BOTH HEAT AND LIGHT BEING BELOW RESPECTIVE THRESHOLD VALUES
First Claim
1. A control apparatus for motor operated venetian blinds comprising, a motor drivingly connected to the venetian blinds to be controlled to operate the same in accordance with the amount of external light to be allowed to pass such venetian blinds, a first sensing means essentially sensitive to light radiation, a second sensing means essentially sensitive to heat radiation, said first and second sensing means being disposed adjacent one another to receive light and heat radiation from the sun, control circuit means having first and second input means connected respectively to said first and second sensing means and an output means connected to said motor to control energization thereof, said first input means having a first threshold value which said first sensing means must exceed, said second input means having a second threshold value which said second sensing means must exceed, said motor being rendered operative upon exceeding either said first or second threshold values to close the venetian blinds and being rendered operative in an opposite direction to open the venetian blinds only when both said first and second sensing means produce a signal below their corresponding threshold values.
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Abstract
Sensing devices respectively reacting to light intensity and to heat radiation are mounted in an exposed position such as on the top of a building. The sensing devices are oriented for direct exposure to sunlight according to the direction of the sunlight at different times of day, and operate through electronic control circuits to operate electric motors, and thereby to control the amount of sunlight admitted through windows on various sides of the building by adjusting the venetian blinds in the windows.
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Citations
8 Claims
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1. A control apparatus for motor operated venetian blinds comprising, a motor drivingly connected to the venetian blinds to be controlled to operate the same in accordance with the amount of external light to be allowed to pass such venetian blinds, a first sensing means essentially sensitive to light radiation, a second sensing means essentially sensitive to heat radiation, said first and second sensing means being disposed adjacent one another to receive light and heat radiation from the sun, control circuit means having first and second input means connected respectively to said first and second sensing means and an output means connected to said motor to control energization thereof, said first input means having a first threshold value which said first sensing means must exceed, said second input means having a second threshold value which said second sensing means must exceed, said motor being rendered operative upon exceeding either said first or second threshold values to close the venetian blinds and being rendered operative in an opposite direction to open the venetian blinds only when both said first and second sensing means produce a signal below their corresponding threshold values.
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2. The control apparatus of claim 1 wherein said first and second sensing means are arranged in a plurality of pairs, each pair having one sensing unit above the other and each pair being angularly displaced relative to one another.
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3. The control apparatus of claim 2 wherein said first sensing means has sensing units mounted above the sensing units of said second sensing means, and the sensing units of said first sensing means are mounted at an inclined angle in correspondence to the seasonal mean position of the sun.
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4. The control apparatus of claim 2 further including a plurality of radial walls separating said plurality of pairs of first and second sensing means into at least three groups.
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5. The control apparatus of claim 1 further including drive means to rotate said first and second sensing means at a rate of one revolution in 24 hours.
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6. The control apparatus of claim 5 wherein said drive means includes a lever, pivotal means for tiltably mounting said lever about a horizontal axis, at least one of said first and second sensing means being mounted to said lever, at its free end, a cam surface positioned below said lever, and a cam follower extending downward from said lever to engage said cam surface, said cam surface effecting tilting of said lever and said sensing means connected thereto to be pointed up substantially to the seasonal mean height of the sun for any given arcuate position.
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7. The control apparatus of claim 6 wherein said lever is mounted to a support plate which is free to rotate about a shaft of said drive means, and a driving arm secured to said shaft and extending therefrom to engage said lever to rotate the same and said support plate to a predetermined position at which said arm passes over said lever as a result of said cam surface and said cam follower, and spring means connected to said support plate to return the same to its initial position after reaching said predetermined position.
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8. The control apparatus of claim 7 further including an impulse transmitting disc secured to and rotatable with said shaft, and circuit means co-acting with said disc to generate control impulses for a predetermined time interval to control respective different ones of a plurality of venetian blinds on different sides of a building depending on the time of day.
Specification