SAFETY SWITCH

Abstract

A safety switch assembly having a handle pivotably attached to a casing to allow selective operation of an electrical contact assembly. The handle is attached to the casing with a movable pivot such that excessive grip pressure renders the safety switch inoperable until the safety switch is reset. The handle is moveable responsive to grip pressures that range from no actuation to a first grip pressure. Actuation of the handle in this range controls operation of the electrical contact assembly. Gripping of the switch with a grip pressure greater than the first grip pressure moves the pivot such that the safety switch is rendered inoperable, or non-conductive, until manipulation of a reset actuator returns the pivot to a pivot position associated with the first operating zone. Such a construction provides a safety switch that can be rendered inoperable and reset to allow subsequent operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which:

FIG. 1 is a schematic representation of an enclosure equipped with a safety switch according to the present invention; and

FIGS. 2 a to 2g depict a safety switch according to an embodiment of the present invention.

Claims

1. A safety switch comprising: a body;at least one electrical component for controlling conduction of electricity by the safety switch; anda handle pivotably attached to the body and pivotable about a pivot point, the handle being pivotable between a first operating zone, a second operating zone and a third operating zone, wherein:the first operating zone corresponds to a situation where the handle is not depressed and the electrical component is arranged such that the safety switch cannot conduct electricity;the second operating zone corresponds to a situation where the handle is depressed to a first extent and the electrical component is arranged such that the safety switch is able to conduct electricity; andthe third operating zone corresponds to the situation where the handle is depressed to a further, second extent, and the electrical component is arranged such that the safety switch cannot conduct electricity,wherein the pivot point is moveable from a first position to a second position when the handle is depressed to the third operating zone, the second position of the pivot point being arranged such that the electrical component is arranged such that the safety switch cannot conduct electricity, irrespective of whether the handle is subsequently moved to the first or second operating zones.

2. The safety switch of claim 1 further comprising a reset actuator which is arranged such that upon moving the handle to the third operating zone, the electrical component is maintained in an arrangement such that the safety switch cannot conduct electricity, until the reset actuator has been activated.

3. The safety switch of claim 2 wherein the reset actuator is arranged to move the pivot point from the second position to the first position.

4. The safety switch of claim 1 further comprising a first biasing member configured to maintain the pivot point in the first pivot point position when the pivot point is in the first pivot point position.

5. The safety switch of claim 1 further comprising a second biasing member configured to maintain the pivot point in the second pivot position when the pivot point is in the first pivot point position.

6. The safety switch of claim 1 further comprising a fulcrum extending from the handle such that upon moving the handle between the second operating zone and the third operating zone, the handle pivots about the fulcrum such that the pivot point moves from the first position to the second position.

7. A powered piece of equipment safety switch arranged to allow control of a supply of power to the equipment comprising: a body;at least one electrical component for controlling conduction of electricity by the safety switch; anda handle pivotably attached to the body and pivotable about a pivot point, the handle being pivotable between a first operating zone, a second operating zone, and a third operating zone, wherein:the first operating zone corresponds to a situation where the handle is not depressed and the electrical component is arranged, such that the safety switch cannot conduct electricity;the second operating zone corresponds to a situation where the handle is depressed to a first extent and the electrical component is arranged such that the safety switch is able to conduct electricity; andthe third operating zone corresponds to the situation where the handle is depressed to a second extent and the electrical component is arranged such that the safety switch cannot conduct electricity,wherein the pivot point is moveable from a first position to a second position when the handle is depressed to the third operating zone, the second position of the pivot point being arranged such that the electrical component is arranged such that the safety switch cannot conduct electricity, irrespective of whether the handle is subsequently moved to the first or second operating zones.

8. The equipment safety switch of claim 7 further comprising a reset actuator arranged such that upon moving the handle to the third operating zone, the electrical component is maintained in an arrangement such that the safety switch cannot conduct electricity, until the reset actuator has been activated.

9. The equipment safety switch of claim 7 wherein the safety switch is arranged to allow the control of the supply of electrical power to the equipment.

10. A safety switch comprising: a body;at least one electrical component for controlling conduction of electricity by the safety switch; anda handle attached to the body and moveable between a first operating zone, a second operating zone and a third operating zone, wherein:the first operating zone corresponds to a situation where the handle is not depressed and the electrical component is arranged such that the safety switch cannot conduct electricity;the second operating zone corresponds to a situation where the handle is depressed to a first extent and the electrical component is arranged such that the safety switch is able to conduct electricity; andthe third operating zone corresponds to the situation where the handle is depressed to a further, second extent, and the electrical component is arranged such that the safety switch cannot conduct electricity,wherein the safety switch further comprises a reset actuator which is arranged such that upon moving the handle to the third operating zone, the electrical component is maintained in an arrangement such that the safety switch cannot conduct electricity, until the reset actuator has been activated.

11. The safety switch of claim 10 wherein the handle is pivotably attached to the body and pivotable about a pivot point.

12. The safety switch of claim 11 wherein the pivot point is moveable from a first position to a second position when the handle is depressed to the third operating zone, the second position of the pivot point being arranged such that the electrical component is arranged such that the safety switch cannot conduct electricity, irrespective of whether the handle is subsequently moved to the first or second operating zones.

13. The safety switch of claim 12 wherein the reset actuator is arranged to move the pivot point from the second position to the first position.

14. The safety switch of claim 11 further comprising a fulcrum extending from the handle such that the electrical component is between the fulcrum and the pivot point.

15. A safety switch comprising: a casing having an electrical contact assembly therein; anda handle attached to the casing and pivotable about a movable pivot, the handle configured to manipulate the electrical contact assembly such that the electrical contact assembly is conductive when a first grip pressure is applied to the handle and the electrical contact assembly is non-conductive when no grip pressure is applied to the handle and when a grip pressure greater than the first grip pressure is applied to the handle.

16. The safety switch of claim 15 further comprising a reset actuator configured to move the pivot only in one direction.

17. The safety switch of claim 16 wherein the pivot is movable between a first position and a second position and the safety switch further comprises a biasing mechanism configured to maintain the pivot in a previous position relative to the casing.

18. The safety switch of claim 17 wherein the reset actuator is configured to move the pivot from the second position to the first position.

19. The safety switch of claim 17 wherein the biasing mechanism further comprises a first spring to maintain the pivot in the first position and another spring to maintain the pivot in the second position.

20. The safety switch of claim 15 further comprising a spring disposed between the handle and the casing and configured to bias the handle to a no grip pressure position.