Pneumatic controller for a printing machine
US5142980A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Apr 17, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65H2555/11
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The pneumatic controller for detecting the presence or absence of sheets fed through a press machine includes a suction system having a suction duct in a sheet feed cylinder of the press machine and a vacuum pump connected to the suction duct, the suction duct opening onto a surface of the sheet feed cylinder on which one of the sheets contacts at least partially obstructing an air flow through the suction duct during normal press operation. To rapidly detect a sudden increase in the air flow through the suction duct caused by a missing sheet, the pneumatic controller is provided with a flow sensor (1) in the suction duct having a hot wire (16) and a surrounding protective jacket (15), and an analyzing circuit (2) connected to the flow sensor. The analyzing circuit (2) detects the temporary cooling of the hot wire (16) caused by the increase in the air flow rate and the analyzing circuit (2) detects the change of resistance of the wire and generates and amplified voltage output signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.