Patent GB-314940-A (GB)
Title: Improvements in methods of and apparatus for making glass vacuum flasks
IPC: C03B23/13
Filed: 1929-04-08
Abstract: 314,940. American Thermos Bottle Co., (Assignees of Wetmore, M. P.). July 5, 1928, [Convention date]. Forming hollow-walled vessels.-A method of making a double-walled vacuum bottle consists in cutting off the rounded lower portion from an outer cylinder, assembling the outer cylinder with an inner cylinder and sealing them together at the necks, and then replacing the rounded portion and seating it to the remainder of the bottle.' The outer cylinders are blown with a circumferential bead or ridge 198, Fig. 10, around each cylinder, and the rounded lower portion 75 is cut off along the bead, thus leaving the upper part 90 and the lower part 75 with flared edges 201, 200, respectively. An inner vessel is inserted in the part 90 and they are sealed together at the neck. A machine for replacing the rounded bottom parts 75 comprises a conical table 38, Fig. 2, which is rotatable about a vertical axis and is turned by hand. The table is provided with a number of vertical hubs 47 in each of which is mounted a tubular bearing secured to an arm 50. A rotary sleeve 52 rotates in each bearing and a hollow shaft 59 is feathered in the sleeve 52. The arm 50 carries a vertical sleeve 54 in which a shaft 55, Fig. 7, is journaled, and the upper end of the sleeve 54 carries an arm 77 in which is fixed a bearing 78. A sleeve 80, journaled in this hearing. carries a head 84 which receives and centres the upper part, 90. of a bottle. The head is rotated by the shaft 55 through gear wheels 79, 83. The lower part 75 of each bottle is supported by a disc 64 secured to the hollow shaft 59, and each shaft 59 is rotated by the shaft 55 in unison with the head 84. The shaft 55 also carries a gear wheel 58 which makes contact with a rubber covered wheel 25 when the table 38 is turned. A number of the wheels 25 are mounted below the table and are geared together by a sprocket chain 34. A shaft 13, driven by a suitable motor, drives the wheels 25, so that the contact between the gear wheel 58 and a wheel 25 causes rotation of the parts of a bottle held by a head 84 and a disc 64. The lower ends of the shafts 59 rest on a cam track 102 which has a section 107 that can be raised by means of a hand lever 117. A lower section 106 of the cam allows the shaft 59 to fall to a lower position to facilitate the loading of the head 84 and disc 64 with the parts of a bottle, and also the removal of a finished bottle. In operation, the table 38 is turned by hand to bring the bottles to successive stopping- points where they are rotated by the wheels 25 and are heated along the flared edges 200, 201 by flames from gas burners 129. At the last stopping-point, the movable section 107 of the cam 102 is raised by the lever 117 to bring the heated flared edges together so that they weld and form a joint. In order to prevent the welded edge from collapsing, air under pressure is supplied to the hollow space in the wall of the bottle through the hollow shaft 59 and the evacuation nipple on the bottom of the bottle. A rotary valve 154, operated by a pedal 178, enables the gas flames in the sealing position to be turned up or down. Another pedal 143 enables the hotter flame used for sealing to be moved vertically so that it plays over the joint. After the joint is made, it is annealed by the flame from a burner 185.