Patent GB-843192-A (GB)
Title: Improvements in or relating to methods of, and apparatus for, severing glass tubing
Inventor: ASHER PHILIP
IPC: C03B33/085
Filed: 1957-04-05
Abstract: 843,192. Severing glass tubing. GENERAL ELECTRIC CO. Ltd. April 1, 1958 [April 5; 1957], No. 11207/57. Class 56. Apparatus for severing into predetermined lengths glass tubing 2 being continuously fed in the direction of its length comprises an annular burner 1 constantly reciprocated along the tubing. During its forward movement the burner travels at the same speed as the tubing and directs on to a narrow annular zone of the tubing a ring of flames from a large number of fine jets the number, concentration and temperature of which are such as completely to melt the glass in that annular zone and so sever it. During the return half of the reciprocation of the burner the flames may be reduced or extinguished. In the form shown in Fig. 1, the various controls are operated from a camshaft 20 driven in phase with the endless chain 8 with the upper and lower flights of which a roller 12 alternately engages, the roller being slidable in a groove 13 on the carriage 5 on which the burner is mounted. Soon after the carriage has started its forward movement the cam 24 closes switch 23 and opens another switch, not shown. The effect of this is to open a valve 22 in the fuel supply to the burner and to energise a timing circuit 25 which closes the valve 22 when sufficient time has elapsed for the burner to sever the tubing. Cam 32 controls a fluidpressure valve to a cylinder 30 to draw a driven roller 26 down into contact with the tubing either immediately before or simultaneously with the severing of the tubing so as to expedite the removal of the severed portion. Cam 19 controls admission of fluid pressure alternately to opposite ends of a cylinder 16, movement of the piston of which effects a rotary oscillation of the burner in its annular housing 15 on the carriage during its rectilinear reciprocation. The timing circuit includes a cold-cathode valve with a control electrode between cathode and anode, a capacitor changeable at an adjustable race being connected between the cathode and control valve to cause the main anode-cathode discharge to take place when the capacitor is charged to a predetermined value. In the form shown in Fig. 4 the controls are actuated by a cam 68 on the carriage 5 and include delay circuits D1 for the fuel supply valve to the burner, D2 for reversing. The direction of travel of the carriage, and D3 for the roller 26. The circuit D2 controls a switch 69 for alternately energising circuits to clutches 64, 65 which alternately move sprocket wheels 61, 62 into engagement with the upper and lower flights of the chain 8. In a modification, the burner may be formed in two semi-circular sections hinged together on a horizontal pivot parallel to the direction of travel. In the forward movement the sections are held together to form a ring ; in the reverse movement they are pivoted away from one another so that, if the flames are not cut off during such reverse movement they no longer impinge on the walls of the tubing. Two such split burners may be used, each on a separate carriage : in this case the carriages move in opposite phases which thus permits severing tubing travelling at double the speed without shortening the heating time, the length of stroke being increased to compensate for the increased speed. Specification 826,270 is referred to.