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US 4,384,280 AGranted
Anti-entry device for surfaces
OwnerGunter Haaginventor
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OwnerGunter Haaginventor
Estimating the term…
An anti-entry device for surfaces in which the edge of the surface to be protected is provided with light-reflecting layers which conduct the light coming from a source of light to a receiver, said receiver being connected to an alarm which is activated when the light to said receiver is disturbed. In order to make the anti-entry device insensitive to adjustment, the light-reflecting layers are formed of elements which reflect an impinging ray of light independently of their angular position, in the plane extending between the layers and parallel to the direction of incidence thereof. These elements are developed as mirror strips which contain 90.degree. angle mirrors or 90.degree. prisms as reflecting elements. Several of such mirrors or prisms can be combined in a single mirror strip. The anti-entry device is used for the securing of surfaces, such as windows, as well as machines and open-field areas. The anti-entry device is adapted to be portable, particularly for the last-mentioned purpose of use.
An anti-entry device for surfaces in which a pair of parallel edges of the surface to be protected are provided with light-reflecting layers which conduct the light coming from a source of light to a receiver which is adapted to generate a signal in response to said light and in which an alarm is given off when said light is disturbed, wherein the light-reflecting layers are formed of elements which reflect an impinging ray of light, independently of its angle of incidence, parallel to the direction of incidence thereof in the plane extending between the layers.
Dependencies are inferred from the claim text.