Pressure control system
First Claim
1. In a pressure control system for regulating the actual fluid pressure in fluid-filled apparatus such as pneumatic devices and the like in accordance with an adjustable desired fluid pressure, wherein the system comprises a source of compressed fluid, means for selecting the desired fluid pressure, valve means connected to the apparatus and selectively connectable to the source of compressed fluid for selectively increasing, decreasing and maintaining the fluid pressure in the apparatus, and control means responsive to the actual fluid pressure and the selection of desired fluid pressure to operate the valve means in accordance with the difference between the actual and desired fluid pressure, the improvement wherein the control means comprises:
- transducer means connected to the apparatus and responsive to the actual fluid pressure to generate an electrical transducer signal continuously proportional to the magnitude of the actual fluid pressure;
first circuit means connected to the means for selecting the desired fluid pressure and to the transducer means, and responsive to the transducer signal for generating electrical valve control signals representative of the polarity of the difference between the desired fluid pressure and the actual fluid pressure;
the valve means is responsive to the electrical valve control signal to continuously and selectively increase or decrease the actual fluid pressure in the apparatus until the actual fluid pressure is within a predetermined range of the desired fluid pressure; and
the first circuit means comprises proportional signal generating means connected to the transducer means and to the means for selecting the desired fluid pressure, and responsive to the transducer signal and the particular selected desired fluid pressure for generating a first difference signal having a value continuously proportional to the magnitude and polarity of the difference between the actual fluid pressure and the desired fluid pressure during increase and decrease of the actual air pressure.
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Accused Products
Abstract
A highly accurate pressure control system (200) adapted to control fluid pressure in apparatus such as the air pressure in vehicle tires (136) comprises a control module (210) having an air pressure selector (211) for selecting a desired air pressure and a pressure to voltage transducer circuit (230) for generating a signal representative of the actual air pressure. Signals representative of the difference between actual and desired air pressure are applied to comparator circuitry (246, 248) which control output switches (254, 256) for activating an inflate/deflate valve (220) to inflate or deflate the tires (136) so as to achieve and maintain the desired air pressure. Various circuitry of the control module (210) employ reference signals maintained at reference values held constant relative to a common power supply voltage instead of to a ground reference (218), thus minimizing circuit count and power dissipation while providing sufficient current for operating output switches (254, 256).
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Citations
18 Claims
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1. In a pressure control system for regulating the actual fluid pressure in fluid-filled apparatus such as pneumatic devices and the like in accordance with an adjustable desired fluid pressure, wherein the system comprises a source of compressed fluid, means for selecting the desired fluid pressure, valve means connected to the apparatus and selectively connectable to the source of compressed fluid for selectively increasing, decreasing and maintaining the fluid pressure in the apparatus, and control means responsive to the actual fluid pressure and the selection of desired fluid pressure to operate the valve means in accordance with the difference between the actual and desired fluid pressure, the improvement wherein the control means comprises:
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transducer means connected to the apparatus and responsive to the actual fluid pressure to generate an electrical transducer signal continuously proportional to the magnitude of the actual fluid pressure; first circuit means connected to the means for selecting the desired fluid pressure and to the transducer means, and responsive to the transducer signal for generating electrical valve control signals representative of the polarity of the difference between the desired fluid pressure and the actual fluid pressure; the valve means is responsive to the electrical valve control signal to continuously and selectively increase or decrease the actual fluid pressure in the apparatus until the actual fluid pressure is within a predetermined range of the desired fluid pressure; and the first circuit means comprises proportional signal generating means connected to the transducer means and to the means for selecting the desired fluid pressure, and responsive to the transducer signal and the particular selected desired fluid pressure for generating a first difference signal having a value continuously proportional to the magnitude and polarity of the difference between the actual fluid pressure and the desired fluid pressure during increase and decrease of the actual air pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a pressure control system mounted to a vehicle for inflating and deflating the actual air pressure of pneumatic vehicle tires in accordance with a desired air pressure adjustably and remotely selected by a vehicle operator, wherein the system comprises a source of compressed air mounted to the vehicle, means mounted within the vehicle cab for selecting the desired air pressure, valve means connected to the pneumatic apparatus and selectively connectable to the source of compressed air for selectively inflating, deflating and maintaining the actual air pressure in the vehicle tires, and control means responsive to the actual air pressure and the selected desired air pressure to operate the valve means in accordance with the difference between the actual and desired air pressures, the improvement wherein the vehicle includes power supply means and the control means comprises:
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transducer means connected to the vehicle tires and to the vehicle power supply means, and responsive to the actual air pressure in the vehicle tires to generate an electrical transducer signal continuously proportional to the magnitude of the actual air pressure; first circuit means connected to the power supply means and to the means for selecting the desired air pressure, and responsive to the transducer signal for continuously generating electrical valve control signals representative of the polarity of the difference between the desired air pressure and the actual air pressure; and the valve means is responsive to the electrical valve control signals to continuously and selectively inflate or deflate the actual air pressure in the vehicle tires until the actual air pressure is within a predetermined range of the selected desired air pressure. - View Dependent Claims (17, 18)
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Specification