Patent GB-534617-A (GB)
Title: Improvements in processes and apparatus for moulding articles from thermoplastic organic materials
IPC: B29C51/40
Filed: 1939-07-10
Abstract: 534,617. Moulding thermo-plastic material. JACKSON, L. MELLERSH-. (Hartford-Empire Co.). July 10, 1939, No. 20060. [Class 87 (ii)] For making an article from a sheet of thermo plastic material, integral perimetrially disposed portions of the sheet are supported against relative movement, an unsupported central portion is exposed to a source of heat radiations to render it plastic and mouldable, the surrounding portion being maintained in a cool rigid condition, the sheet and source of heat are moved apart, the heated portion is shaped by pressure, and sufficient heat is extracted from the heated portion during the shaping operation so that the portion will retain the shape. As shown in Fig. 3 a sheet 1 of organic plastic material is clamped between members 2, 3 of a frame which protects the edges against heat. After the central portion has been placed over heating means so that it is heated by radiation, it is operated upon by dies 9, 10 to form a hollow article which is subsequently severed from the rest of the sheet. The sheet may be formed with slits 143 as shown in Fig. 14 or with slits 145 as shown in Fig. 17. In a modification, a number of separate sheets and holders are mounted on a rotary table, which brings each sheet in turn into successive positions above heating means and between moulding and cutting dies. The invention may be carried out in a continuous process, as illustrated-in Fig. 11, in which the application is to the production of nasal inhalers. A ribbon 23 of plastic material is brought between heating means 24, 25 whereby the central part of the ribbon is heated while the side portions are kept relatively cool by guides. The guides may be cooled by means of air or water chambers. The ribbon is advanced intermittently to successive stations. At station B the articles are formed by dies 26, 27 provided with passageways 28 for cooling fluid. At station C members 29, 30 are provided for perforating the bottoms of the articles. At station D there is a reservoir 34 for adhesive ; the reservoir has openings 33 adapted to be closed by a valve 32 on the end of a member 31. The reservoir enters the article and relative downward movement of the member 31 causes adhesive to be applied to the sides of the article. At station E co-operating members 36, 37 act in conjunction with a collar 39 whereby a wad of cotton 35 is inserted in the article around a centring pin 38. At station F cutting dies 40, 41 sever the articles from the ribbon 23. A machine for carrying out the process illustrated above is shown in Fig. 20. Plastic material is fed as a strip 90 from a reel, and the edges of the strip are bent at right angles by means of rolls 96, 98. Heating means 100 facilitates the bending of the edges which are held in grooves in guides. At station N the centre portion of the strip is heated by members 66, 58. At station O, dies 102, 103 operated by cam mechanism from a main shaft 86, form cup-like depressions in the strip. Pipes 108, 109 are provided to pass heating or cooling fluid into channels in the dies. The strip is fed intermittently by rolls 111, 112 at station P, the roll 111 being driven from the shaft 86. At station Q each depression in the strip receives a wad of cotton from a feeding device comprising a rotatable head 119 with spindles 120. The head 119 is rotated intermittently from the shaft 86 and the spindles 120 are rotated at their uppermost position, being driven from a clutch member 124 splined to a continuouslyrotating vertically disposed shaft. Cotton is wound on each spindle during its rotation, by means of feed rollers 129, 130. 'The cotton is stripped from each spindle 120 in its lower-most position, by means of a collar 125 carried by a transverse plate 126 which is mounted on a radially-slidable shaft. This shaft is operated, through cam mechanism, from the main shaft 86. The depressions in the strip are cut out by means of a punch 131 and a die 132, and the resulting articles are delivered through a shoot 139. Specifications 474,001 and 464,436 are referred to.