| 摘要 |
<p>A safety switch for a glass door, which is used for refrigerating and deep freeze chambers and comprises tow or more glass panes of hardened glass, of which the front pane (21) remote from the refrigerating and deep freeze chamber is heated by an electrically conductive layer attached on the inner surface of the pane, which layer is connected to an upper and, respectively, lower collecting conductor, and the rear pane (22) facing to the refrigerating and deep freeze chamber is provided with at least one conductor attached on the pane. The conductors are connected to a current scanning device (20), which is capable to scan whether current flows through said collecting conductors and the conductor of the rear pane, and which is capable to break the connection between the conductors of the two panes (21,22) and a voltage source (46) in the event that current does not flow in the collecting conductors and/or in the conductor of the rear pane. According to the invention, the current scanning device comprises a per se known type of fuse (21) of porcelain, on which conductors are located. The current scanning device (20) is capable to increase the current intensity through said fuse (21) in the event that current does not flow in the collecting conductors and/or in the conductor of the rear pane, whereby the porcelain fuse (21) is heated so as to crack, whereby the conductors on the fuse (21) are broken.</p> |
