[KevinCarlson]

[quote=Mr. Steve]Quoted from the FIRST Pneumatics Manual:


Hello everyone,

I'm doing some research on the internet and happening to into this msg forum. I see you guys are discussing something about pressure switch & control system. Maybe you can help me out. I'm looking at someone's patent and one of the independent claim that person makes is that he uses a pressure switch to turn on a PWM circuit/controller when the liquid pressure is low enough to trigger the switch. The exact claim is " Pressure switch can sense the output pressure, said pressure switch activating said pulse width modulating circuit when output pressure is less than a threshold value". I believe the claim is too broad. I meant people have been using pressure switch and pwm for decades. I'm looking at some proof to invalidate that claim. If you guys happen to know any product or publication out there prior to 2001, please let me know.

Thanks,
Kevin