GB312594A - Improvements relating to respiratory gas masks or face pieces - Google Patents

Abstract

312,594. Jones, F. C. Feb. 28, 1928. Moulding indiarubber respirators -Face-pieces for respirators are formed by press moulding rubber or like material on a flat plate-like core between a pair of half moulds. The face-pieces, an interior perspective view of one of which is shown in Fig. 4, are of strong flexible rubber and comprise, (1) portions 2, 3 closely engaging the chin, cheeks and forehead and having tabs 13 for connection with head straps, (2) gogglelike eye-piece sockets 5 outstanding towards the upper and outer sides of the mask, (3) channels 7, 9 leading the inhaled air over the eye-pieces and thence to the nostrils, (4) annular sockets 11 to receive exhaling valves, and (5) a partition 10 engaging the upper lip and preventing direct access of air to the nostrils. The inhaled air is drawn through a tube 6 formed with a terminal bead 6a for connection with the respirator-box and the channels 7, 9 are stiffened by integral longitudinal ribs 8. The moulding apparatus shown in Figs. 5 and 6 produces a mask normally folded along the centre line of the face and comprises a pair of complemental moulds such as' 7 and a thin plate-like core 16 engaging a recess 15 therein. The core 16 is formed with cvlindrical projections 23 having beaded edges 25 co-operating with annular depressions 24 in the moulds to form the eyepieces, ribs 28, 29 having central depressions 30 forming with depressions 31, 32 in the moulds, the ribbed channels 8, 9, a U-shaped slot 36 forming the partition 10, and flat discs 19, having thin peripheral flanges 35, which co-operate with annular depressions 20 in the moulds to form the valve sockets 11. The inhaling tube 6 is formed by a cylindrical portion 21 on the core co-operating with similar depressions 33, formed with annular recesses 34, in the moulds. Shallow rulings 39 on the core form a roughened portion on the mask improving the contact thereof with the face. The core contacts with the moulds over its unformed portion and at the points 26, 20<a> and 22, Fig. 5. The moulds 17 are formed with cut-away portions 40 to facilitate handling and with channels 42 for the removal of gases during moulding. Two facepieces may be moulded simultaneously by making the moulds and the core double ended.