Patent GB-313146-A (GB)
Title: Improvements in machines for making glass vacuum bottles
IPC: C03B23/13
Filed: 1929-03-25
Abstract: 313,146. American Thermos Bottle Co., (Assignees of Wetmore, M. P.). June 9, 1928, [Convention date]. Forming hollow-walled vessels.-Relates to the method of manufacturing vacuum flasks in which an inner vessel having one end closed is inserted in an outer vessel, and the vessels are welded together along their upper rims. According to the invention, the rims are heated until the glass is plastic, and the plastic rims are forced together to unite them in a sealed joint by means of mechanical pressure applied simultaneously to both rims around the entire circumference, the joint then being annealed. Welding.-The machine comprises a base 10, Fig. 1, supporting a cam shaft 14 and two horizontal tables 38, 162 which are rotated step by step and carry the flasks during the sealing and annealing operations, respectively. The sealing- table 38 is provided with a series of vertical bearings 54, Fig. 7, and on the upper end of each bearing a disc 56 rotates. The disc is secured to a sleeve 58 which is journaled in the bearing 54, and a pinion 59 secured to the lower end of the sleeve engages a large gear wheel 42. This wheel rotates on the bearing of the shaft of the table 38 and simultaneously rotates all the gears 59, and discs 56. Each disc 56 carries two vertical rods 62 on which two collars 64, 65 are adjustably secured. The two collars act as supports for an outer glass blank 66 and an inner glass vessel 67 which are nested together and are placed in the collars neck downwards with their rims 73 closely adjacent to one another. A rod 78 which slides through the sleeve 58 carries at its upper end a centering disc 85, and a heavy metal block 83 provided with an annular bevelled groove 84. The disc 85 is of slightly less diameter than the neck of the inner vessel 67 and holds the assembled vessels in line with the groove 84 of the block 83. The rod 78 in raised periodically by means of a pin 87 which slides through a sleeve 88 fixed to the table 10 below, and coaxial with, the rod 78 when it is in the sealing-position. The pin is pivoted to one end of a lever 93, the other end of the lever riding on a cam 98 on the shaft 14. The cam 98 is so shaped that the block 83 is suddenly thrown upwards at the proper time, so that it lifts the vessels off the collars 64, 65 and forces the plastic edges 73 into contact with one another to form a joint. The block 83 then lowers the vessels on to the collars again, leaving them ready to be transferred to the annealing device. Before the vessels are transferred, however, the joint is smoothed by pointed gas flames from jets 136, Fig. 1, and during this operation, air is blown from a jet 151 into the space between the walls of the vessels in order to prevent the sealed edges from collapsing. Annealing.-The annealing table 162 is formed with openings in which sheet metal cylinders 166, Fig. 22, are supported. Each cylinder contains an asbestos pad 171 for supporting a sealed flask F<1>, and is provided at the top with a removable metal ring 172 for centering the flask. A ring 205 mounted below the table 162 carries a number of gas burners 210, one for each cylinder, and during the periods of rest of the table 162, the flames of the burners heat the sealed necks of the flasks. The flames are so regulated that the joint is annealed by the time it ha,s travelled around the table. Transfer mechanism. - The flasks are transferred from the sealing-table to the annealing- table by means of a suction head 235, Fig. 1, carried by an arm 211 which swings horizontally about a shaft 214 that is movable vertically. A valve 249, operated by a. cam 264 on the shaft 14, regulates the application of suction and of atmospheric pressure at the head 235. Operation.-In the operation of the device, the tables 38, 162 are rotated step by step. A pair of glass vessels, assembled as shown in Fig. 7. is placed on the collars 64, 65 at station I, and are carried around by the table while being constantly rotated. The lower edges 73 of the vessels are heated until soft by flames from gas burners 113. At station IX. the edges are sealed together by the block 83 and are smoothed by the flames from burners 136. The flask is then transferred to a cylinder 166 and annealed.