| 摘要 |
1488440 Detecting breakage of window panes SAINT-GOBAIN INDUSTRIES 22 Dec 1975 [24 Dec 1974] 52339/75 Heading G4N A window pane having a tempered glass sheet 1 has an extensometric detector 6 integral with the surface thereof so that on breakage of the pane a signal is provided for operating an alarm or protection device. As shown, the detector 6 is a resistance strain gauge mounted on the bottom face of a block 4 which is bonded at 5 to the sheet 1. The block 4 also contains a second strain gauge 7 identical to gauge 6 but not in contact with the sheet 1, the two gauges being arranged in a bridge, Fig. 2 (not shown), also mounted in block 4. The bridge output is amplified and applied to a relay, Fig. 2 (not shown), via a lead 9. As shown, the pane consists also of a non-tempered glass sheet 3 and a thermoplastic adhesion layer 2. |
