A switch for optical fibers and anti-effraction fence made by utilizing said switch

Claim 2

A switch for optical fibres, characterized in that it comprises means (7,9; 41,41′,47,48,64) for deflecting a cable (5) of optical fibres, which cooperate with a length of the optical fibre cable (5), and are movable between a conductive position in which the path of said length of the optical fibre cable (5) is in correspondence of the deflecting means (7,9; 41,41′,47,48,64) substantially straight, and at least one interruptive position in which the deflecting means (7,9; 41,41′,47,48) temporaneously deflect the cooperating length of the optical fibre cable (5) in one or more points, in such a manner that owing to a signal dispersion at the bend or bends in the deflected length of the cooperating optical fibre cable (5), the transmitted signal will be attenuated under a predetermined threshold value.

Claim 3

The switch according to Claim 1, characterized in that the deflecting means (7,9; 41,47,48) present a stable conductive position and an unstable interruptive position.

Claim 4

The switch according to Claim 1, characterized in that the deflecting means (64,47,48) can be freely moved into at least one interruptive position and into conductive position.

Claim 5

The switch according to Claim 1, characterized in that the deflecting means (7,9; 41,47,48) present a stable, either conductive or interruptive position and an unstable, either interruptive or conductive position.

Claim 6

The switch according to Claim 1, characterized in that the deflecting means (41,41′47,48) present a stable interruptive position, an unstable conductive position, and an unstable interruptive position.

Claim 7

The switch according to any one of Claims 3 or 5 characterized in that the deflecting means present two extreme interruptive positions and an intermediate conductive position.

Claim 8

The switch according to Claims 4 and 5, characterized in that the switch is provided with antagonistic elastic means (10,51) for automatically restoring the stable, either interruptive or conductive position of the deflecting means (7,9; 41,41′,47,48).

Claim 9

The switch according to any one or more of the preceding Claims, characterized in that the length of the optical fibre cable which cooperates with the deflecting means (7,9; 41,41′,47,48) has such an inherent elasticity that it spontaneously regains at least in part its substantially straight path, in the conductive position of the said deflecting means.

Claim 10

The switch according to any one or more of the preceding Claims 1, 2 and 4 to 8, characterized in that auxiliary elastic means are provided for restoring the conductive straight path of the length of optical fibre cable (5) which cooperated with the deflecting means (7,9; 41,41′,47,48).

Claim 11

The switch according to Claim 9, characterized in that the auxiliary means for restoring the straight path of the optical fibre cable (5) consist of elastic means putting under tension the said cable (5).

Claim 12

The switch according to any one or more of the preceding Claims, characterized in that the deflecting means is made in form of a slider (7,41,41′,C) having a transversal opening (46,107,141′,164) for passing therethrough the optical fibre cable (5) and at least one deflecting edge (9,47,48) provided in correspondence of said opening (46,107,141′,164) and pointing to the cable, which slider (7,41,41′,C) cooperates with at least one stationary abutment for the cable (5), provided at least one side of the deflecting edge (9,47,48).

Claim 13

The switch according to any one or more of the preceding Claims, characterized in that the optical fibre cable (5) is received so as to be freely slidable in the longitudinal direction thereof, in a guide in the slider-carrying member (1,1′,40,G) which is co-axial to the transversal opening (46,107,141′,164).

Claim 14

The switch according to Claim 7, characterized in that a spring (10,51) serving as an antagonistic means is provided for restoring the stable position of the slider (7,41,41′) and is interposed between an abutment surface of a stationary slider-carrying member (1,3,40) and an abutment surface the slider (7,41,41′).

Claim 15

The switch according to Claims 11 to 13, characterized in that the guide for the optical fibre cable (5) is delimited by the top end surface of a stationary slider-carrying member (3) and by the top end wall of a switch housing (1), and the spring (10) is interposed between a pre-load adjusting screw (12) and the top end side of the slider (7).

Claim 16

The switch according to Claim 14, characterized in that the optical fibre cable (5) presents in the interruptive position five deflected points (18,19,20,21,22) situated in correspondence of the deflecting edge (9) and of the edges of an opening (2) provided in the top end wall of housing (1), through which the slider (7) travels, and also in correspondence of an opening (4) in the slider-carrying member (3) for the travel of the slider (7), and of the edges of the top end surface of the slider-carrying member (3).

Claim 17

The switch according to the preceding Claims 14 and 15, characterized in that means are provided on the housing (1) for locking the slider (7) in the unstable, either conductive or interruptive position.

Claim 18

The switch according to Claim 16, characterized in that the locking means are constituted by a pawl (28) fulcrumed about the outer sides of housing (1) and cooperating with a groove (108) provided in the top end outward surface of slider (7), which pawl (28) keeps the slider (7) in its unstable position by being engaged in the said groove (108) and by being kept in its slider-locking position by the antagonistic elastic means (10) acting upon the slider (7), the said pawl being disengaged by the action of a return spring (29) from the said groove (108) after a limited displacement of the slider (7) against the action of the said antagonistic elastic means (10).

Claim 19

The switch according to Claims 11 to 13, characterized in that the slider is constituted by a pin (41) with a transversal groove (46) therein, and with its transversal walls made in form of spires (47,48) facing each other, which pin is housed in a tubular body (40) formed with a transversal slot (43) extending for about 180°, and through which the optical fibre cable (5) is passed, a spring (51) for restoring the stable positions being fitted between a head (44) of pin (41) and the top end surface of the tubular body (40), and an abutment nut (45) which cooperates with the bottom end surface of the tubular body (40), being screwed in the pin (41) from the end side of the said tubular body (40) which is opposite to its head (44).

Claim 20

The switch according to Claim 18 characterized in that the tubular body (40) and the pin (41) may be circular in cross-section and may be provided with means for preventing their relative rotation.

Claim 21

The switch according to Claims 11 to 13, characterized in that the slider is made in form of a platelet (41′) with a transversally recessed portion (141′) and with the walls of the said recessed portion which are transversal to the sliding direction of the said platelet (41′), constituting two opposed deflecting edges (47,48) for deflecting the optical fibre cable (5), which platelet (41′) is slidably received into coinciding openings (101′) in one of the end walls and in an intermediate wall of a housing (1′), the sidewalls of housing (1′) which are parallel to the platelet (41′) being formed, in the region of the recessed portion (141′) in platelet (41′), with apertures (43) for an optical fibre cable (5) to be passed therethrough, and the said platelet (41′) is provided on its end lying within the compartment (301′) which is delimited by the intermediate wall and the other end wall of housing (1′), with a transversally extending appendix (53) serving as a limit stop abutment for the platelet (41′), a spring (51) being fitted between the said appendix (53) and the end wall of housing (1′) which is opposite thereto.

Claim 22

The switch according to Claims 1, 3, 6, 8, 9, 11, 12, characterized in that it consists of an L-shaped, switch-fastening and slider-guiding member (G), with its leg (58) being parallel to the switch-fastening plane (70) and being provided in its side which is turned toward the said switch-fastening plane (70), with a slider-guiding recess (59) and in its side which is opposite to the switch-fastening plane, with a groove (60) for receiving an optical fibre cable (5), which extends transversally to the slider guide (59) and penetrates to a substantial degree into the said guide, and the slider (C) consists of a block (62) for a firm connection thereto of a control element, such as a cable or wire (61), or the like, and is of a height substantially corresponding to the distance between the switch-fastening plane (70) and that side which is turned toward the said plane of the said leg (58) of the switch-fastening and slider-guiding member (G), the said slider (C) being engaged from below in the slider-guiding recess 59 by means of two appendices (64) which are in line with, and are spaced apart from each other in the longitudinal direction of the slider-guiding recess (59), and by their wedge-like tapering sides the said appendices (64) provide the deflecting edges (47, 48) for deflecting an optical fibre cable (5).

Claim 23

The switch according to Claim 21, characterized in that the control element (61) is so fastened to the block (62) that its lengthwise extension is parallel to the slider guide (59).

Claim 24

An anti-effraction fence made by using any one or more of the switches according to Claims 1 to 22, characterized in that it consists of a row of upstanding poles (P) to which a fencing network may be applied, with a plurality of cables or wires (61), particularly horizontal, equispaced wires, being stretched along the said pole row, and these horizontal cables or wires may particularly consist of metallic cables or wires, plastics cables, sheathed or strengthened optical fibre cables, or the like, and each one of these cables, wires (61), or the like, can be locked in position (as by 72) close to the said poles, or the same can control an intrusion-warning sensor (S) sensing that a wire or cable (61), or the like, is being pushed apart.

Claim 25

The fence according to Claim 23, characterized in that a maximum of two immediately following intrusion-warning sensors (S) are provided for each cable, wire (61), or the like, it being possible to provide poles (PB) having only locking elements (B, 72), poles (PS) having only intrusion-warning sensors (S), and poles (PM) having locking elements (B, 72) and intrusion-warning sensors (S) in a random arrangement.

Claim 26

The fence according to Claim 23, characterized in that an optical fibre switch according to Claims 21 and 22 is used as intrusion-warning sensor, with a cable or wire (61), or the like, being fastened to the slider (C) thereof, the sliding direction (arrow F) of the said slider (C) being parallel to the longitudinal direction of the said cable or wire (61), or the like.

Claim 27

The fence according to any one or more of the preceding Claims 22 to 25, characterized in that it consists of stiff poles (PB, PS, PM) to which a U-profiled member (70) for mounting the intrusion-warning sensors (S) and the locking elements (B, 72) is respectively secured, while a further U-profiled member (75) serving as a covering for preventing the access to the said elements (S, B, 72) is fixed on to the U-profiled member (70), one or more switches for optical fibres according to Claims 14 to 20, particularly according to Claim 20, being provided on each pole to act as detectors (A) for detecting the removal of the covering, and being attached to the U-profiled member (70) so as to have the sliding direction of the deflecting means (41′) arranged at right angles with the covering, and being held in their unstable conductive position, when the said covering is in assembled condition.

Claim 28

The fence according to any one or more of the preceding Claims, characterized in that each pole has an upward, particularly inclined, extension (76) which is like the poles (PB, PM, PS), and which can be fixed to the associated pole (PB, PM, PS) with the interposition of a switch for optical fibres according to Claims 1 to 22, particularly according to Claims 14 to 20.

Claim 29

The fence according to Claims 23 to 25, characterized in that it consists of a row of flexible poles (P), a box (80) being provided for each cable or wire (61) at each flexible pole (P), and the said box (80) is provided with means (81) for being removably engaged with a flexible pole (P), and houses an intrusion-warning sensor (S) or an element (B, 72) for locking in position the associated cable or wire (61), or the like, and a switch for optical fibres according to Claims 14 to 20, particularly according to Claim 20, which acts as a detector (A) for detecting that a cover (83) is being removed and also that a box (80) is being taken off a flexible pole (P).

Claim 30

The fence according to Claim 29, characterized in that the detector (A) for detecting the removal of the cover (83) from a box (80) is slidably received in a guide (84) which is perpendicular to the cover (83), an arm (85) being provided, which with the box in assembled condition, is fitted through an opening in the bottom wall of box (80), between the end surface of the switch for optical fibres which is turned toward a flexible pole (P) and the said pole (P), whereby the deflecting means are held in their unstable conductive position, when the box (80) has its cover (83) thereon, and the said box (80) is fitted on a flexible pole (P).