| 摘要 |
Glass sheets are toughened by exposing the heated glass sheet to a gaseous chilling medium and interposing between at least a part of the central area of the glass and the gaseous medium a series of parallel members 4 of width small in comparison with the sheet width, e.g. angle bars which present their concave faces to the glass sheet. The bars 4 <PICT:1095284/C1/1> <PICT:1095284/C1/2> are connected by members 5. The toughened sheet thus formed has lesser toughened interrupted vertical strips breaking to a relatively large particle size separated by narrow bands of more highly toughened glass breaking to a relatively small particle size (Fig. 4), thus providing a vision zone in the central area of the sheet after fracture. To reduce the screen effect of the bars 4 notches may be cut in their edges at regular intervals along their length. This causes partial intersection of the strips of less toughened glass by the more highly toughened glass. To further aid in the screen effect a wire gauze may be attached to the series of bars 4. The concave faces of the angle bars may be coated with alternate bands of heat-reflecting material and heat-absorbent material. |
