Pressure setting device
AssigneeKabushiki Kaisha Cosmo Keiki
InventorsAkio Furuse, Yoshihiro Honma
Life of this patent
Estimating the term…
Abstract
In a device in which a positive or negative pneumatic pressure source is coupled with a controlled system through a first electromagnetic valve and the controlled system is coupled with a negative or positive pneumatic pressure source through a second electromagnetic valve or opened therethrough to the air, and which is adapted so that the first and second electromagnetic valves are controlled to open or close to thereby set an air pressure in the controlled system, a deviation between the pressure of the controlled system and the set pressure is detected and the detected deviation signal is converted by a pulse converter into a pulse of the duty ratio or frequency corresponding to the deviation, by which pulse the first and second electromagnetic valves are controlled to open or close.
Claims9
A pressure setting device comprising:
- a pneumatic pressurizing source;
- a pneumatic depressurizing source;
- a controlled system;
- a first electromagnetic valve inserted in a pipe interconnecting the pneumatic pressurizing source and said controlled system for applying and cutting off air pressure from the pneumatic pressurizing source to said controlled system;
- a second electromagnetic valve inserted in a pipe interconnecting the pneumatic depressurizing source and said controlled system for reducing the pressure applied to said controlled system;
- a pressure sensor for detecting, as an electric signal, the pressure of the controlled system;
- a deviation detecting comparator for producing a deviation signal representative of a deviation between the output from said pressure sensor and a set value;
- a full-wave rectifier for converting the value of the deviation signal into an absolute value;
- a pulse converter for converting the absolute value of the deviation signal into a pulse signal having at least one of the parameters pulse width, pulse interval, and frequency corresponding to the magnitude of the absolute value;
- first and second drive circuits adapted to be controlled by an output pulse from the pulse converter to drive the first and second electromagnetic valves, respectively;
- a selecting comparator for detecting the polarity of the deviation signal to produce a selection signal;
- and a selection circuit responsive to said selection signal for determining which one of the first and second drive circuits is to be supplied with the output pulse from said pulse converter.
Dependencies are inferred from the claim text.