Abstract: A testing system to test safety interlock switches to ensure that they are operating normally comprising a test loop circuit 16 which connects in series a plurality of safety switches 2, the test loop circuit 16 is adapted to open the switches 2 outputs if broken, the testing system further comprising a diagnostic means 18 which checks each switch to ensure it is operating normally when the test loop circuit 16 is broken. The test loop circuit 16 may be broken when a single switch 2 is activated to open its safety output.

Abstract: A safety interlock switch with coded interlocking to provide tamper resistance, the coded interlocking having two differently coded technologies 8,10; 16,18. In a preferred embodiment one technology is mechanical in the form of a coded-cam system operated by a coded-tongue 8, the other is electronic comprising a non-contact coded RFID sensor 16,18, and wherein the switch is only enabled when the two different codes have been correctly applied.

Abstract: The present invention relates to an anti-tamper cam system 2 used to selectively operate a safety interlock switch 6. The cam system 2 comprising a cam 12 selectively rotatable between two positions in order to activate the switch 6. The cam 12 has a locking system 20, 22; 32a, 32b to lock the cam 12 in one of its positions. The locking system 20, 22; 32a, 32b comprises a separate mechanical locks 20, 22; 32a, 32b on each side of the cam 12, each of which must be unlocked using a dedicated key actuator 8 before the cam 12 can be rotated to its other position.

Abstract: A solenoid plunger 14 of the switch 4 is moved by cam plunger 34 and is biased towards the cam plunger 34, a locking plate 40b is positioned between the plungers 14 and 34. Cam 34 is biased for movement towards a cam 22 and is moved towards the solenoid plunger by rotation of the cam 22 by removal of actuator 8 which causes retraction of the solenoid plunger into the switch 4. The locking plate 40b is lockable when the cam plunger 34 is biased into a detent 36 in the cam 22 when the actuator is inserted, to lock the cam plunger 34 and cam 22 and prevent removal of the actuator 8.

Abstract: A safety interlock switch with coded interlocking to provide tamper resistance, the coded interlocking comprising two differently coded technologies 8,10; 16,18. In a preferred embodiment one technology is mechanical in the form of a coded-cam system operated by a coded-tongue 8, the other is electronic comprising a non-contact coded RFID sensor 16,18, and wherein the switch is only enabled when the two different codes have been correctly applied.

Abstract: A solenoid plunger 14 of the switch 4 is moved by cam plunger 34 and is biased towards the cam plunger 34, a locking plate 40b is positioned between the plungers 14 and 34. Cam 34 is biased for movement towards a cam 22 and is moved towards the solenoid plunger by rotation of the cam 22 by removal of actuator 8 which causes retraction of the solenoid plunger into the switch 4. The locking plate 40b is lockable when the cam plunger 34 is biased into a detent 36 in the cam 22 when the actuator is inserted, to lock the cam plunger 34 and cam 22 and prevent removal of the actuator 8.

Abstract: The present invention relates to an anti-tamper cam system 2 used to selectively operate a safety interlock switch 6. The cam system 2 comprising a cam 12 selectively rotatable between two positions in order to activate the switch 6. The cam 12 has a locking system 20, 22; 32a, 32b to lock the cam 12 in one of its positions. The locking system 20, 22; 32a, 32b comprises a separate mechanical locks 20, 22; 32a, 32b on each side of the cam 12, each of which must be unlocked using a dedicated key actuator 8 before the cam 12 can be rotated to its other position.

Abstract: A safety switch 2 used in conjunction with a cable as a machine guard, the switch being actuated to cut power to attendant machinery when a predetermined tension in the cable is varied by for example pulling the cable, or the cable becoming loose. The switch 2 comprising a sliding cam 14 which is connected to a connection point 12 for the cable via a spring loaded shaft 10 which shaft also supplies said predetermined tension and acts to move said sliding cam 14 in a first plane when the predetermined tension is varied. The sliding cam 14 then acts on a transverse cam 36 moving it in a plane transversely disposed to said first plane which in turn acts to cut said power 30, 52.

Abstract: A rope tensioner is used, for example, to connect a rope 1 under tension to a safety switch whereby the switch operates, e.g., to turn off power to machinery guarded or bounded by the rope in the event that the rope tension departs significantly from a predetermined value. The rope tensioner ensures a firm gripping of the rope 1 reducing risk of the rope 1 slipping and losing the required tension. The rope tensioner comprises to this end a housing 2 with passageways 16,17 to receive the rope 1 running between main inlet and outlet locations and a clamp 14 to apply a clamping force transverse to the rope 1 at a clamping location 8 within the passageway 16, 17, the passageway having sections running in opposed directions.

Abstract: A safety switch 2 used in conjunction with a cable as a machine guard, the switch being actuated to cut power to attendant machinery when a predetermined tension in the cable is varied by for example pulling the cable, or the cable becoming loose. The switch 2 comprising a sliding cam 14 which is connected to a connection point 12 for the cable via a spring loaded shaft 10 which shaft also supplies said predetermined tension and acts to move said sliding cam 14 in a first plane when the predetermined tension is varied. The sliding cam 14 then acts on a transverse cam 36 moving it in a plane transversely disposed to said first plane which in turn acts to cut said power 30, 52.

Abstract: A rope tensioner is used, for example, to connect a rope 1 under tension to a safety switch whereby the switch operates, e.g., to turn off power to machinery guarded or bounded by the rope in the event that the rope tension departs significantly from a predetermined value. The rope tensioner ensures a firm gripping of the rope 1 reducing risk of the rope 1 slipping and losing the required tension. The rope tensioner comprises to this end a housing 2 with passageways 16,17 to receive the rope 1 running between main inlet and outlet locations and a clamp 14 to apply a clamping force transverse to the rope 1 at a clamping location 8 within the passageway 16, 17, the passageway having sections running in opposed directions.