Patent GB-252371-A (GB)
Title: Method of and apparatus for making hollow blown glassware
IPC: C03B9/193
Filed: 1926-05-18
Abstract: 252,371. Hartford-Empire Co., (Assignees of Canfield, R. W.). May 19, 1925, [Convention date]. Blowing.-Relates to the manufacture of hollow blown glassware having thin walls, such as electric lamp .bulbs and tumblers. The principal feature of the invention consists in suspending a glass blank by its marginal portion and allowing .t to distend downwardly whilst it is being heated. the distension being opposed by gaseous pressure in order to regulate the elongation and lateral expansion of the parison. Apparatus for carrying out this method of parison formation is shown in Figs. 1 and 4 and comprises a combined press and blow head 42, a ring mould 13, a blank mould 20. a finishing mould 104. and burners 100 the flames from which supply the gaseous pressure for regulating the formation of the parison. Ring and blank moulds. The ring mould is supported in a circular opening in a table 3, and the two halves 13 of the mould are pivoted to a gear ring 5 which is mounted in ball bearings 6. The gear ring can be rotated by means of a crank handle 16 through a bevel gear 14. The blank mould is carried by an arm 17 pivoted on a bracket 18 below the table 3. and consists of a casing 20 with a replaceable carbon inset 21 formed with a cavity 23 pf the desired shape to mould a charge 24 of glass. The arm 17 swings in a vertical plane, and is held in contact with the ring mould by a hook 25 which engages a pin on a lever 23<a>. A pin 28, coaxial with the carbon inset, dislodges the blank from the mould when the arm 17 is swung downwards. Press and blow head. The combined pressing and blowing mechanism 42 comprises a barrel 43 which is rotatably mounted in a bearing 44 formed at the end of an arm 45. The lower end of the barrel 43 is provided with a head 49 which enters between curved members 50, connected to the upper end of the ring mould holders 12, and locks the mould. The charge of glass 24 is pressed bv a plunger 62 carried by a stem 63 which slides within a tube 51 extending coaxially through the barrel 43. Compressed air is supplied to the space between the stem 63 and the tube 51 by means of a pipe 57 and ports 56, 59. A spring 65 withdraws the plunger into the tube during the blowing operation, and a cam 75, which is operated by a pivoted yoke 73, forces the plunger downwards, to the position shown in Fig. 4, for the pressing-operation. A stripper ring 70 surrounds the lower end of the tube 51 and is pressed downwards bv a spring 72. The arm 45 which supports the head slides on a vertical post 77, and it is raised and lowered, and also swung horizontally, by a lever 80. Finishing mould. The finishing mould 104 consists of two halves 105, Fig. 1, hinged on a pin 107 which is carried on an arm 108 that can be swung horizontally. The mould is opened and closed, and also swung to and from the position beneath the ring mould, by a lever 111 connected by links 112 with the mould halves. The links are formed with notches which engage pins on the mould halves and are kept in engagement with them by springs. By disengaging the links from the pins, the mould halves may be lifted off their pivot 107 for replacement. A sprayer 122 may be provided to cool the mould. Operation of the machine. After the blank mould receives a charge of glass, the lever 80 is moved to lower the head 42 and pressure is applied to it to form the charge into a blank. The lever 23<a> is then moved to release the arm 17 which swings downwards, and its movement releases the yoke 73 from the cam 75 thus allowing the spring 65 to withdraw the plunger 62 into the tube 51. The operator now rotates the blank by the crank 16 and at the same time he moves under the blank a burner 95 and provided with a number of nozzles 100. Flames from these nozzles play on the blank, as shown in Fig. 6, and reheat it, and the flame from a central burner 101 also tends to retard the sagging of the parison. Air is then blown into the parison to expand it, and blowing and reheating is continued until the parison is of the required shape and wall thickness. The burner is then removed, and when the parison has sagged to the required extent, the finishing mould is closed around it and blowing and rotation is continued until the article obtains its final form.