776,061. Photo-electric control systems. GUSTIN-BACON MANUFACTURING CO., Inc. Dec. 24, 1953 [April 1, 1953], No. 35835/53. Class 40 (3). [Also in Group XXVIII] In a tube-making machine comprising a tensioned endless belt 50 extending around rollers 16, 24, 30, 42 and 44, the rollers 42, 44 being mounted on a pair of rotatable arms 36, and a mandrel 76 supported on rotatable arms 64, a beam of light from a lamp 114, Fig. 3, is directed in front of the motor-driven roller 16 and on to a photo-electric cell 116 controlling a thyratron 302, Fig. 6. The control circuit shown in Fig. 6 is adapted to operate either manually or automatically and a switch 230 determines the kind of operation to be employed; in the automatic position a lamp 232 is illuminated. In operation, a solenoid 320 is energized and actuates a valve 322 permitting air pressure to flow to a motor which drives the arms 36 to an " up " position as seen in Fig. 1 in which position a switch 48 is closed, whereby a solenoid 324 is energized to operate an air valve 326 so that a motor also drives the arms 64 to an " up '' position; simultaneously, a solenoid 328 is energized to cause a valve 330 to supply air to a manifold P. When the arms 64 reach the upward limiting position thereof a switch 68 is opened to de-energize the solenoid 328 so that the valve 330 cuts off the air supply. Energization of a solenoid 332 moves a valve 334 to a position whereby centres 82, Fig. 4, are driven outwardly by an air motor 84, the centres in the inward position engaging in the hollow shaft 78 of the mandrel 76. With the arms 64 in the " up " position as shown in Fig. 1, an operating cycle is initiated by placing a mandrel 76 upon V-blocks 72, thereby closing switches 74 de-energizing the solenoid 332 to cause the valve 334 to move to a position whereby air pressure is supplied to the motors 84 which drive the centres 82 into the mandrel shaft 78, after which the solenoid 328 is energized to move the valve 330 to supply air to the manifold P and the solenoid 324 is de-energized to move the valve 326 to a position whereby air pressure is supplied to the motor driving the mandrel arms 64. The latter are rotated in a clockwise direction as seen in Fig. 1 to lift the mandrel 76 from the V-blocks 72 and to abut stops 67 and also operate a switch 110 to cause the solenoid 320 to rotate the valve 322 to a position such that air from the manifold P is communicated to the motor 33 which drives the arms 36 in a clockwise direction and against stops 47 and to open a switch 112 to cut off the air supply to the motors actuating the arms 36, 64. A fibrous mat 122, Fig. 3, to be wound on to the mandrel 76 and placed on a conveyer 118 moves to the left as seen in the Figure to interrupt the beam of light from the lamp 114 so that movement of the arms 36, 64 back to the " up " position thereof is delayed. After the mat has been fully wound upon the mandrel the light again acts on the cell 116 which through the thyratron 302 causes solenoid 328 to be energized to move the valve 330 to a position in which air is supplied to the manifold P. Solenoid 320 controlling the valve 322 is energized so that the arms 36 are driven in an anticlockwise direction to abut the stop 46 and close a switch 48 to establish a circuit through the solenoid 324 which actuates the valve 326 so that air passes to the motor operating the arms 64, the latter being moved in an anticlockwise direction to abut against stops 66 and open a switch 68 whereby the solenoid 328 moves the valve 330 to interrupt the air supply to the motors operating the arms 36, 64. The mandrel with the wound mat thereon is re-positioned in the V-blocks 72. Specification 777,823, [Group XXVIII], is referred to.