Abstract: A safety arrangement for use with a piece of equipment. The safety arrangement includes a signal generating unit for generating an optical signal, an elongate element, and a signal detecting unit. The elongate element is disposed along, about, around or through the piece of equipment and is capable of transmitting an optical signal. The signal detecting unit detects an optical signal. The signal generating unit is connected to the signal detecting unit by the elongate element such that the signal detecting unit is in optical communication with the signal detecting unit. The signal detecting unit is arranged to detect a change in the optical signal transmitted by the elongate element as a consequence of movement of the elongate element and, upon detection of the change in the signal, the detecting unit is configured to effect a change in the operation of the piece of equipment.

Abstract: A safety switch that includes a body, a number of contacts, a movable plunger, a signal emitter, and a signal detector. The signal emitter and signal detector are positioned proximate the plunger and configured to assess the operability of the safety switch. The plunger is configured to selectively allow or prevent passage of a signal emitted from the signal emitter toward the signal detector depending on a position of the plunger. Control circuitry in connection with the signal detector is arranged to generate a control signal based on the detection of the emitted signal and configured to control operation of the safety switch independent of the relative position of the number of contacts.

Abstract: A radial latching mechanism for engaging a safety switch is described. The radial latching mechanism includes an actuator holder, and an actuator for engaging the safety switch, attached to the actuator holder in a predetermined orientation relative to the holder. The mechanism has a body for supporting the actuator holder, and a first radial member extending between and pivotally connected by respective pivot points to both the body and the actuator holder. The radial latching mechanism further includes a second radial member extending between and pivotally connected by respective pivot points to both the body and the actuator holder. Each pivot point has a pivot axis, all of the pivot axes being substantially parallel.

Abstract: There is provided a safety switch having a housing configured to receive a removable key, and a mechanism arranged to be operated when the key is moved from an engaged position to a partially disengaged position, the mechanism being arranged to cause a signal to pass to a separate apparatus, wherein the safety switch further comprises a lock which is controlled by the separate apparatus and is arranged to prevent the key from being fully disengaged from the safety switch until a signal has been received in response from the separate apparatus.

Abstract: A safety switch operating mechanism having an engagement mechanism mechanically linked to a plunger and arranged to receive an actuator such that insertion of the actuator into the engagement mechanism moves the plunger to a first position and removal of the actuator from the engagement mechanism moves the plunger to a second position. The safety switch operating mechanism having a resilient member which engages with the plunger and resiliently resists movement of the plunger from the first position to the second position. The engagement of the resilient member with the plunger resists inadvertent removal of the actuator from the engagement mechanism.

Abstract: A switch mechanism has at least one set of contacts including at least one fixed contact and at least one moveable contact which is carried by an axially moveable carrier that is held by a spring-loaded detent when the contacts are closed, the carrier being released with a force to overcome the latching mechanism when opening the contacts, and a cam member with at two cam profiles that is disposed adjacent one end of the carrier and is operable to pull the axially moveable carrier towards the cam and thereby pull the at least one moveable contact into engagement with the at least one fixed contact. In one embodiment, the cam may carry a permanent magnet which when moved attracts and draws with it a permanent magnet mounted fixedly with respect to the axially moveable carrier.

Abstract: A locking switch assembly includes a cam, a plunger, and a locking mechanism. The cam is rotatably attached to a frame assembly and an end of the plunger is constructed to follow a contour of the cam. The plunger is movable between a plunger first position and a plunger second position. A pin is biased against the plunger and movable between a pin first position and a pin second position and locks the plunger in the plunger second position when the pin is in the pin second position. A breakable arm prevents movement of the plunger from the plunger second position to the plunger first position unless a force above a selected amount is applied to the cam when the plunger is in the plunger second position.

Abstract: A switch mechanism embodying the invention comprises a switch head assembly with at least one stationary contact and at least one movable contact carried by an axially movable contact carrier, a cam head assembly, a plunger assembly with a sealing element and a U-shaped yoke. The sealing element comprises a bellows seal having an outer peripheral rim that is trapped between the switch assembly housing and the tulip end of the cam head housing on assembly thereof. The bellows seal further comprises an inner annular part that is over molded onto the plunger body where and has a relieved portion comprising V-shaped troughs and ridges and undercutting in the form of annular grooves that open towards one another. The relieved portion provides a positive connection between the sealing element and the plunger and the tracking path for preventing liquid ingress is increased significantly.

Abstract: A rotary safety switch assembly is disclosed in which electrical contacts are movable from a power supply OFF position to a power supply ON position by movement of a rotary member contained within a housing, the electrical contacts comprising first stationary contacts and second movable contacts, and in which the first stationary contacts are carried by a housing part and the second movable contacts are carried by the rotary member and are movable therewith in an arc about said predetermined axis to make and break contact with the first stationary contacts in response to movement of the rotary member by the actuator.

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 rope tensioner sets the tension of a rope operated switch assembly actuable to switch between first and second conditions on a change in tension of the rope. The tensioner comprises a body, a rotatable member which engages the rope, a shaft for rotating the member relative to the body to adjust tension in the rope by winding the rope around the member, and a lock to lock the member in position relative to the body. The rope opperated switch assembly is much simpler to install than previous assemblies, as the tensioner may be simply threaded or otherwise installed onto the rope without the rope having to be cut.

Abstract: A valve lock for locking a valve spindle in a selected position corresponding to the valve being for example fully open or fully closed. The lock has a housing which is mounted on the valve body and a hub which engages and rotates with the valve spindle relative to the housing. A latch is provided between the housing and the hub, the latch being actuatable by a key to assume a latched condition in which rotation of the hub relative to the housing is permitted in one direction but prevented in the other direction. A spindle position indicator is coupled by a transmission to the hub as to be displaced as a result of rotation of the spindle, thereby to indicate the spindle position relative to the valve body. The spindle position indicator prevents actuation of the latch by the key except when the spindle is in the selected position as represented by the spindle position indicator.

Abstract: A rope gripper for connecting for example a rope operated switch to a rope. The gripper comprises a body defining a passage into which a rope can be inserted. Two jaws are mounted eccentrically on pivot pins on either side of the passage and biased towards the passage such that they are pressed against an inserted rope. The jaws are shaped and mounted such that movement of an inserted rope in one direction along the passage drives the jaws towards the rope, causing the rope to be jammed within the passage, whereas movement of the rope in the opposite direction along the passage drives the jaws to a position in which the rope is free to slide.

Abstract: A valve lock for locking a valve spindle in a selected position corresponding to the valve being for example fully open or fully closed. The lock has a housing which is mounted on the valve body and a hub which engages and rotates with the valve spindle relative to the housing. A latch is provided between the housing and the hub, the latch being actuatable by a key to assume a latched condition in which rotation of the hub relative to the housing is permitted in one direction but prevented in the other direction. A spindle position indicator is coupled by a transmission to the hub so as to be displaced as a result of rotation of the spindle, thereby to indicate the spindle position relative to the valve body. The spindle position indicator prevents actuation of the latch by the key except when the spindle is in the selected position as represented by the spindle position indicator.