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 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 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.

Abstract: A lockable switch mechanism for a machine guard includes a switch plunger and locking and switch mechanisms. The plunger moves, upon insertion of an actuator, between two positions to actuate the switch mechanism and is locked by the locking mechanism, which has one locking member biased against a surface of the plunger and another locking member that is displaceable between locked and released positions. The plunger has an annular shoulder that displaces the first locking member when the plunger is moved. The second locking member prevents displacement of the first locking member by the plunger to thereby prevent movement of the plunger. Thus removal of the actuator is prevented unless the second locking member has been moved to the unlocked position when the machine is in a safe condition.

Abstract: A lockable switch mechanism for a machine guard includes a switch plunger and locking and switch mechanisms. The plunger moves, upon insertion of an actuator, between two positions to actuate the switch mechanism and is locked by the locking mechanism, which has one locking member biased against a surface of the plunger and another locking member that is displaceable between locked and released positions. The plunger has an annular shoulder that displaces the first locking member when the plunger is moved. The second locking member prevents displacement of the first locking member by the plunger to thereby prevent movement of the plunger. Thus removal of the actuator (and for example opening of an associated machine guard door) is prevented unless the second locking member has been moved to the unlocked position by for example a solenoid which is energised when the guarded machine is in a safe condition.

Abstract: A safety switch assembly for use with a machinery guard enclosing kinetic machinery, comprises a housing, an electrical contact arrangement and a rotatable actuator cam contained within the homing for operating the electrical contact arrangement and spaced from the electrical contact arrangement. Radial pockets are formed in the actuator cam and extend inwardly of the periphery of the latter. An axially-movable rod connects the electrical contact arrangement and the actuator cam to operate the former in accordance with rotational movement of the latter. The housing defines at least one entry adjacent the actuator cam for insertion of an actuator into the housing to engage the radial pockets to rotate the actuator cam. Anti-rotational locking means releasably engage the actuator cam to prevent rotation of the latter and consequent operation of the electrical contact arrangement until a separation of the actuator cam and the anti-rotational locking means is effected by the actuator.