Patent GB-422436-A (GB)
Title: Improved method and means for the production of double-walled glass vessels
IPC: C03B23/13
Filed: 1933-12-04
Abstract: 422,436. Glass manufacture. DICHTER, J., 8, Hauptstrasse, Sch÷neberg, Berlin. Dec. 4, 1933, No. 34077. Convention date, Dec. 24, 1932. [Class 56] Relates to the production of vacuum flasks by the method in which a cylindrical outer vessel is shaped about the neck of a preformed inner vessel. According to the invention, the heating and shaping of the outer vessel, and the joining of the two vessels together, is carried out in a number of consecutive working positions instead of being completed at a single operation. A machine for carrying- out the method comprises a number of tubular holders 2, Fig. 3, arranged in a circle on a support 40 secured to a shaft 1 which is rotated step-by-step by a Geneva mechanism 5, 51 driven by a shaft 44. Each holder is formed with a sleeve 41 which is journalled in the support 40 and is fitted with a gear wheel 42 which engages a gear wheel 43 rotatable on the shaft 1. The main driving-shaft 44 rotates the wheel 43, so that the holders 2 rotate continuously. A series of counter holders 25, mounted coaxial with the holders 2 in a support 40<1> similar to the support 40, are also rotated continuously by a wheel 431. The counter-holders 25 hold the flasks 3 in the holders 2 during the operation of the machine, and they are kept in contact with the flasks by a circular abutment 26 which has a gap 30 to allow longitudinal movement of the counter holders while the holders 2 are being charged. The flasks are pressed by the counterholders into contact with resilient caps on pins 29 the stems of which are in contact with an abutment 98. The pins 29 are hollow and air may be blown through them, into the holders 2, by a blowhead 16 applied to an opening in the bearing in which the stem of each holder is journalled. When making the flasks, a preformed inner vessel 4, Fig. la, is placed in an outer vessel 3 which has one end closed, the vessels being separated by asbestos spaces 50. The assembled vessels are placed in a trough 6, Fig. 4, and are lifted one at a time, by an oscillating lifter 7, into position between arms 8 on a feed chain 9 which is driven in unison with the support 40. When the pair of vessels are opposite the lowermost holder 2, they are thrust into it by the counter holder 25, which is moved longitudinally by a reciprocating rod 99, Fig. 3, having an arm 31 which engages a flanged sleeve 32 on the stem of the counterholder 25. As the support 40 rotates, the abutment 26 keeps the counter holder in contact with the vessels. In successive stations where the support 40 is at rest, the end of the outer glass vessel is heated by a gas burner 85, Fig. 1<a>, and a shoulder 86, Fig. 1<b>, is formed by a conical roller 87 which is moved into contact with the soft glass. Another roller 88, Fig. 1<c>, forces the ends of the vessels into contact with one another, so that they become welded, the neck of the inner vessel being flared slightly if desired by a tiltable finger 89, Fig. 1d, and the neck may be given a final shaping by a mould 12, Fig. 1f. The finished flask is moved out of the holder 2 on to the feed chain 9 by a second arm 31<1>, Fig. 3, on the rod 99. The chain 9 carries the finished flasks through a cooling chamber 19, Fig. 4, where the rate of cooling can be controlled by gas burners. The necks of the flasks can be formed with internal or external screw threads. These may be formed by means of moulding-rollers which press the soft glass against a supporting member, or they may be formed by means of mould members which are screwed off the vessels when the thread is formed. In the latter case, air is blown into the space between the walls of the flasks by the blowhead 16, Fig. 3, Pouring lips may also be formed on the flasks by the mould 12, Fig. 1f, or by a device similar to the finger 89, Fig. 1d.