GB526613A - Improvements in the production of glass vessels - Google Patents

Abstract

526,613. Shaping glass tubes. DICHTER, J. March 22, 1939, Nos. 9076 and 9077. Convention dates, March 23, 1938 and April 14, 1938. [Class 56] Relates to a method of forming vials, ampoules, and like vessels by softening a portion of a glass tube and drawing the ends of the tube apart so as to constrict the softened glass and to form a length of reduced diameter. According to the invention, the zone of heating is moved towards one end of the tube during drawing to enable a constricted portion of uniform diameter to be obtained. The invention may be applied to a machine of the kind described in Specifications 364,211, 423,419, and 477,552 in which a glass tube 9 is held and rotated by chucks 8, 10 carried by a revolving frame. A tube 9 is heated by burners 39, and when the glass has softened, a shaping roller 55 is pressed against the softened part to constrict it. The chuck 10 is then lowered by a stationary cam 42-44 to draw-out the tube. The burners 35 slide on vertical rods and are connected by a rod 49 with a roller running on a stationary cam 48. As the tube is drawn out, the burners are raised by the cam so that more of the upper end of the tube is heated. After the drawing, the gas supply is cut off and a groove is formed in one or both shoulders on the tube by a separate burner 62 and a tool 61. The groove may also be formed by a ridge on the roller 55 and it serves to facilitate the subsequent division of the tube. The burners 35 may also be used to divide the tube and they may be moved to any convenient position for the purpose. A constriction with sections of different diameter may be produced by varying the speed of movement of the chuck 10, by moving the burners 35 along the tube during drawing, or by varying the supply of gas to the burners. The invention may be applied, also, to constructions in which the tubes are arranged horizontally. Specification 505,744 also is referred to.