GB881168A - Improvements in the starting and stopping arrangements of machines for operating upon or treating webs or sheets - Google Patents

Abstract

881,168. Printing processes; drying-apparatus. TIMSONS Ltd. July 13, 1959 [July 11, 1958], No. 22312/58. Class 100(2) [Also in Group XIII] A machine for operating upon or treating a travelling web or a series of fed sheets of paper or the like is combined with an apparatus including a chamber containing at least one heating device for drying the web or sheets after being so operated upon or treated, means for establishing a stream of cooling air through the chamber and means for controlling the heating device or devices, the arrangement being such that the machine cannot be operated to feed and operate upon the web or sheets, and the heating device or devices cannot be operative to supply heat to the web or sheets, unless air is flowing through the chamber to exercise control over the heat within the chamber. A web W printed by a plate cylinder 1 co-operating with an impression cylinder 2 is dried in a chamber 22 provided with gas burners 30, 31. The burner 31 is fixed while the burner 30 is pivotally mounted for actuation towards and away from the web by a pneumatic actuator 48. A pressure switch 27, in an exhaust duct connected to a fan 24, controls the actuation of contacts 29 in the circuit of a driving motor 3, such that these contacts remain open until a flow of air has been established through the duct 26. A timing mechanism 34, driven in synchronism with the motor 3, has a shaft 38 carrying rotary cams 39 each actuating a switch, e.g., 40. Gas supply valves 35, 36 are actuated by solenoids 41, 43 respectively, these solenoids each being in circuit with a switch actuated by a rotary cam 39. A solenoid 46 controlling a valve 47 supplying a pneumatic actuator 48 is energised by a further camcontrolled switch. Further cam-controlled switches are connected to solenoids 52, 57 which acuate valves 51, 56 respectively connected to pneumatic actuators 54, 59. The actuators 54, 59 are arranged to render operative and trip the cylinder 2 and an inking unit 12 respectively. In operation, fan 24 is started thereby closing the contacts 29 through closure of switch 27 to permit energisation of the motor 3 by manual depression of a button A. The valve 35 is opened to supply gas to the burner 30 which is directed away from the web. The burner is then lit as the web is advanced, valves 51 and 56 being actuated through the solenoids 52, 57 respectively when the web reaches a predetermined speed to cause the cylinder 2 and unit 12 to be rendered operative. The burner 30 is then rotated towards the web and the valve 36 is opened to supply the burner 31. The reverse sequence is followed when the motor 3 is decelerated. The temperature of the chamber 22 is maintained substantially constant during operation by a valve 68 pivotally mounted the duct 26 and actuated by a pneumatic actuator 66 controlled by a valve 65 having a solenoid connected to a thermostat 63. Should the fan 24 stop switch 27 is opened to de-energise the motor, thereby shutting off the supply to burners 30, 31 and tripping the impression cylinder 2 and inking unit 12. The pneumatic actuators 48, 54 and 59 may be replaced by hydraulic actuators. Specification 872,004 is referred to.