AU2015204303A1 - Safety Device - Google Patents

Abstract

A safety device (10) for use on electrical switches (14) of the type in which an actuator (22) is operated to open and close an electrical circuit, the safety device (10) comprising a housing having a first housing portion (24) fixedly mounted in position relative to the actuator (22) and a second housing portion (34) that is movable relative to the first housing portion, The second housing portion (34) is movable from a closed position at which the second housing portion prevents operation of the actuator and an open position at which operation of the actuator is allowed. The first housing portion (24) includes a plurality of apertures (61-66) and the second housing portion includes a plurality of apertures (51-56), wherein the plurality of apertures (51 56) on the second housing portion (24) are positioned adjacent to and in alignment with the plurality of apertures (61-66) on the first housing portion (24) when the second housing portion (34) is in the closed position such that a plurality of sets of aligned apertures are formed, each set of aligned apertures being able to receive a shackle of an individual lock.

Description

1 2015204303 14 Jul2015

TITLE Safety device TECHNICAL FIELD

[0001] The present invention relates to a safety device. The safety device is for use with electrical switches, such as electrical isolation switches.

BACKGROUND ART

[0002] Many pieces of machinery require electrical power to operate. For example, excavators, dump trucks, graders, dozers, highway trucks, 4X4 utilities and other vehicles will typically have an engine (such as a diesel engine) that requires battery power to start and operate. Other pieces of machinery, such as conveyor systems, lighting plants and the like may be predominantly powered by electrical power. Compressors and generators may also have an engine that requires electrical power to start and operate. Much of this machinery is used on mine sites and in mines.

[0003] In order to enhance the safety of machinery used on mine sites and in mines, many pieces of machinery are fitted with a main battery isolator switch and/or a starter isolator switch. These isolator switches allow a single switch to cut electrical power to the machinery or to the starter motor of the machinery. These electrical isolator switches enable isolation of electrical power from the machinery in cases of emergency or when maintenance work or upgrade work on the machinery is required.

[0004] When maintenance work or upgrade work on a piece of machinery is required, the electrical isolator switch may be operated to isolate the machinery from the source of electrical power. In this manner, the risk of the machinery being inadvertently started or operated whilst a worker is working on the machinery is minimised. To further enhance worker safety, safety lockouts are often used. Safety lockouts typically require that a worker uses a padlock to be locked in position close to the electrical switch to warn others that the electrical switch should not be operated, or to prevent others from operating the electrical switch. In some instances, the shackle of the padlock passes through aligned apertures in arms that, when locked together, prevent operation of the switch.

[0005] If multiple workers are required to conduct work on a piece of machinery, it is common practice to use a hasp as part of the safety lock out system. The hasp will typically 2 2015204303 14M2015 comprise two arms that are pivotally connected together. The hasp also has two plates having a plurality of holes formed in them, with the plates being connected to the arms and being pivotal relative to each other. If two or more workers are to work on a piece of machinery, the hasp is applied and each worker will place their own padlock through aligned holes in the two plates of the hasp, which locks the hasp in position. As each worker completes the work required on the piece of machinery, he removes his padlock from the hasp. The hasp can be released and removed and the switch becomes operable only when every worker has finished working on the machinery. Although hasps allow multiple workers to lock out a piece of machinery, hasps are not always available, can become lost and represent additional cost.

[0006] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0007] The present invention is directed to a safety device, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0008] In a first aspect, the present invention provides a safety device for use on electrical switches of the type in which an actuator is operated to open and close an electrical circuit, the safety device comprising a housing having a first housing portion fixedly mounted in position relative to the actuator and a second housing portion that is movable relative to the first housing portion, the second housing portion being movable from a closed position at which the second housing portion prevents operation of the actuator and an open position at which operation of the actuator is allowed, the first housing portion including a plurality of apertures, the second housing portion including a plurality of apertures, wherein the plurality of apertures on the second housing portion are positioned adjacent to and in alignment with the plurality of apertures on the first housing portion when the second housing portion is in the closed position such that a plurality of sets of aligned apertures are formed, each set of aligned apertures being able to receive a shackle of an individual lock.

[0009] In one embodiment, the first housing part comprises a base having an opening therein, the actuator of the electrical switch extending through the opening or being connected to the switch through the opening when the base is fixedly mounted in position relative to the actuator. The first housing part may also comprise a leg, arm or a plate extending away from the 3 2015204303 14 Jul2015 base, the leg, arm or the plate including the plurality of apertures. The plurality of apertures may comprise a plurality of spaced apertures that are aligned along a generally straight line. The leg, arm or plate may extend generally perpendicularly to the base.

[0010] In one embodiment, the second housing part may comprise a first wall that, in the closed position, extends outwardly from the base and a second wall that covers the actuator when in the closed position. The second housing portion may comprise a flange or a lip extending from the second wall, the flange or lip including the plurality of apertures. The plurality of apertures may comprise a plurality of spaced apertures that are aligned along a generally straight line. The flange or lip may extend generally perpendicularly to the second wall. The second housing part comprises a cover.

[0011] The housing may further comprise a stop member that is located adjacent to the actuator when the second housing portion is in the closed position. The stop member may provide an additional barrier to operation of the actuator when the second housing portion is in the closed position. The stop member may comprise a plate extending from the second housing portion. The stop member may comprise a projection or an abutment extending from the second housing portion.

[0012] In some embodiments, the housing presents a closed front to personnel when in the closed position. The housing may have open sides. In other embodiments, the housing may have closed sides.

[0013] In one embodiment, the second housing portion is hingedly connected to the first housing portion. In other embodiments, the second housing portion may be slidable relative to the first housing portion. In other embodiments, the second housing portion may be positioned relative to the first housing portion in the closed position and the second housing portion may be connected to or locked into position with the first housing portion.

[0014] The first housing portion may include one or more fixing apertures to enable the first housing portion to be fixedly mounted relative to the actuator. The first housing portion may be fixedly mounted relative to the actuator by screwing or bolting the first housing portion to the switch or to a member to which the switch is mounted.

[0015] The first housing portion and the second housing portion may be made from any suitable rigid material. In one embodiment, the first housing portion and/or the second housing portion are made from metal. In another embodiment, the first housing portion and/or the second housing portion are made from plastic. 4 2015204303 14 Jul 2015 [0016] In use of the present invention, where it is required that an electrical switch, such as an electrical isolator switch, be locked out so that a worker can work on a piece of machinery that receives electrical power via the electrical switch, the electrical switch is operated to the "off" position. The second housing portion is then moved to the closed position. In this position, the apertures in the first housing portion and the apertures in the second housing portion form sets of aligned apertures. The worker passes the shackle of a padlock through one set of the aligned apertures and locks the padlock. A safety tag will often also be placed on the lock. The worker retains the key to that padlock. As the housing is now locked in the closed position, other workers cannot operate the electrical switch. Therefore, the electrical switch cannot be inadvertently turned on by other workers when the first worker is performing maintenance on the piece of machinery. When the first worker is finished working on the machinery, the first worker returns to the housing, unlocks padlock and removes the padlock. The second housing portion can then be moved to the open position and the electrical switch can be operated to provide power to the machinery.

[0017] If a second worker has to perform work on the machinery whilst the first worker is still working on the machinery, the second worker can place the shackle of a second padlock through another set of aligned apertures in the housing. The second worker locks that second padlock and retains the key. The second worker can then commence work on the machinery. If the first worker completes his task, the first worker can remove his padlock from the housing. However, the second padlock is still in position and thus it is not possible to operate the electrical switch whilst the second worker is still working on the machinery and whilst the second padlock is locked through the aligned set of apertures. In this manner, ease of operation and enhanced safety is provided.

[0018] In one embodiment, the first housing portion may have two or more, or three or more, or four more, or five or more, or six or more apertures. The second housing portion may have two or more, or three or more, or four more, or five or more, or six or more apertures. In one embodiment, the first housing portion may have six apertures and the second housing portion may have six apertures. In this embodiment, up to 6 workers may block out the electrical switch at any given moment.

[0019] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0020] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common 5 general knowledge. 2015204303 14 Jul 2015

BRIEF DESCRIPTION OF DRAWINGS

[0021] Various embodiments of the invention will be described with reference to the following drawings, in which: [0022] Figure 1 shows a front view of a safety device in accordance with an embodiment of the present invention, with the second housing portion being in a closed position; [0023] Figure 2 shows a front view of the safety device shown in figure 1 with the second housing portion being in an open position; [0024] Figure 3 shows a perspective view from below of the safety device shown in figure 1 with the second housing portion being partly closed; [0025] Figure 4 shows a perspective view from above of the safety device shown in figure 1 with the second housing portion being partly closed; [0026] Figure 5 shows a perspective view from above with the second housing portion being in the closed position; and [0027] Figure 6 shows a front view of the safety device as shown in figure 1 with two padlocks being attached thereto.

DESCRIPTION OF EMBODIMENTS

[0028] It will be appreciated that the drawings have been provided for the purpose of illustrating a preferred embodiment of the present invention. Therefore, it will be understood that the present invention should not be considered to be limited solely to the features as shown in the attached drawings.

[0029] The safety device 10 shown in the attached drawings is in the form of a safety lock out that is used to prevent unauthorised actuation or operation of an electrical safety switch. As best shown in figure 4, electrical isolation switches 12, 14 are mounted to a member, in this case bracket 16. The bracket 16 is an F-shaped bracket having a vertical wall 18. The vertical wall 18 is provided with openings (not shown) such that actuators 20, 22 (see figure 2) that operate the electrical isolator switches 12, 14 extend through the vertical wall 18. The actuators 20, 22 may comprise rotating switches, rotatable keys, toggle switches or the like. Other actuators, such as pushbutton switches, may also be used. The electrical isolator switches 12, 14 are of 6 conventional design and need not be described further. 2015204303 14 Jul 2015 [0030] The attached figures show two separate safety devices 10 and 11. Safety device 10 is painted yellow and is used to prevent unauthorised operation of a starter isolation switch, which can be used to cut all power to the starting circuit. Safety device 11 is painted red and is used to prevent unauthorised operation of a battery isolation switch which cuts all battery power to the piece of machinery. Safety devices 10 and 11 are essentially identical to each other, save for their colour. Accordingly, more detailed description of safety device 10 will only be provided.

[0031] The safety device 10 is in a closed position in figure 1 and is in an open position in figure 2. The safety device 10, when in the closed position, is in the form of a housing that is enclosed on four sides but has two open sides. The housing includes a first housing portion 24. First housing portion 24 is fixedly mounted to the vertical wall 18 of the bracket 16. In order to enable the first housing portion 24 to be fixed to the vertical wall 18, the first housing portion 24 is provided with openings 26, 28 that can receive fasteners, such as a screw or bolt 30 that enables the first housing portion 24 to be fixedly mounted to the vertical wall 18 of bracket 16. As the first housing portion 24 is fixedly mounted to bracket 16, the first housing portion 24 is fixed in position relative to the electrical isolator switch 14.

[0032] The first housing portion 24 is also provided with a larger opening 32. The larger opening 32 allows the actuator 22 to be connected to the electrical isolation switch 14. It will be appreciated that the appropriate connections between the actuator 22 and the electrical isolation switch 14 extend through opening 32. The actuator 22 maybe fixed in position once the first housing portion 24 has been mounted to the vertical wall 18 of bracket 16.

[0033] The safety device 10 also includes a second housing portion 34. The second housing portion 34 may be moved from an open position as shown in figure 2 to a closed position as shown in figure 1. As can be seen in figure 2, the second housing portion 34 is hingedly connected to the first housing portion 24 by hinge 36. This allows the second housing portion to be hinged upwardly to move to the open position shown in figure 2 and to be hinged downwardly to move to the closed position as shown in figure 1.

[0034] The first housing portion 24 includes a base 38 that is fixed to the vertical wall 18 of bracket 16, as described above, and an arm or plate 40 that extends generally perpendicularly to the base 38. The second housing portion 34 includes a top wall 42, a front wall 44 and a lower flange or lip 46 (the terms top, front and lower are used in the context of their orientation when the second housing portion is in the closed position as shown in figure 1). The inside of front 7 2015204303 14 Jul 2015 wall 44 carries a stop member 48, which is in the form of an angled plate fixed to the front wall 44. When the second housing portion 34 is in the closed position, the stop member 48 lies in close proximity to actuator 22 and acts to prevent rotation and actuation of actuator 22. The base 38 of the first portion carries a stop member 50 in the form of an L-shaped bar. Stop member 50 at least partly overlies actuator 22 and prevents removal of actuator 22 from the electrical isolation switch 14.

[0035] As can best be seen in figure 2, the lower flange or lip 46 has a series of six holes 51, 52, 53, 54, 55, 56. Similarly, the arm or plate 40 of the first housing portion 24 is also provided with a series of six holes 61, 62, 63, 64, 65, 66. Holes 51 to 56 lie along a generally straight line, as do holes 61 to 66. Holes 51 to 56 and holes 61 to 66 have essentially identical diameters and come into index or alignment with each other when the second housing portion 34 is in the closed position. This is best shown in figure 5.

[0036] When it is necessary for a worker to work on a piece of machinery, such as for maintenance or upgrading, the worker will actuate the electrical isolation switch 14 to turn off electrical power and close the second housing portion 34 to the closed position as shown in figures 1 and 5. That worker will then place the shackle of a safety padlock through, for example, aligned holes 51 and 61 to thereby lock the safety device 10 in the closed position. A safety tag may be attached to the padlock. It will be appreciated that when the safety device 10 is in the closed position, the second housing portion 34 presents a closed front face to any other workers, which effectively prevents actuation of the actuator 22. The safety device 10 has open sides (as can be seen from figure 5). However, stop member 48 prevents actuation of the actuator through the open sides of the safety device 10.

[0037] If a second worker has to also carry out work on the piece of machinery, the second worker can attach his safety padlock, for example, through aligned holes 52 and 62. Figure 6 shows a first padlock 70 that has its shackle inserted through aligned holes 51 and 61, and a second padlock 72 that has its shackle placed through aligned holes 52 and 62. If the first worker completes his task, the first worker returns to the safety device 10 and unlocks and removes his padlock 70. However, as the second worker is still working on that piece of machinery, his padlock 72 is still being used to lock the safety device 10 in the closed position. Therefore, the first worker (and indeed, any other workers) cannot actuate isolation switch 14, thereby ensuring enhanced safety for the second worker. It is only when both the first worker and the second worker have removed their safety padlocks that the safety device 10 can be opened and the actuator 22 used to return power to the starter circuit. 2015204303 14 Jul 2015 8 [0038] The safety device of the present invention may be subject to various modifications. For example, instead of having a series of six aligned holes, a different number of holes may be used. The safety device 10 shown in the attached figures is made from metal. The various components may be shaped and drilled as required. However, the safety device may be made from any other suitable rigid material, such as rigid plastic. The safety device may be provided with closed sides rather than two open sides. This may be achieved for example, by providing the first housing portion with side walls extending out from the base 38. Different stop members may be used. For example, if a pushbutton actuator is provided, the stop member mounted to the inside of front wall 44 of the second housing portion 34 may comprise an open cylindrical member that surrounds the pushbutton actuator when the second housing portion is in the closed position.

[0039] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0040] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0041] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims (20)

1. A safety device for use on electrical switches of the type in which an actuator is operated to open and close an electrical circuit, the safety device comprising a housing having a first housing portion fixedly mounted in position relative to the actuator and a second housing portion that is movable relative to the first housing portion, the second housing portion being movable from a closed position at which the second housing portion prevents operation of the actuator and an open position at which operation of the actuator is allowed, the first housing portion including a plurality of apertures, the second housing portion including a plurality of apertures, wherein the plurality of apertures on the second housing portion are positioned adjacent to and in alignment with the plurality of apertures on the first housing portion when the second housing portion is in the closed position such that a plurality of sets of aligned apertures are formed, each set of aligned apertures being able to receive a shackle of an individual lock.

2. A safety device as claimed in claim 1 wherein the first housing part comprises a base having an opening therein, the actuator of the electrical switch extending through the opening or being connected to the switch through the opening when the base is fixedly mounted in position relative to the actuator.

3. A safety device as claimed in claim 2 wherein the first housing part comprises a leg, arm or a plate extending away from the base, the leg, arm or the plate including the plurality of apertures.

4. A safety device as claimed in claim 3 wherein the plurality of apertures comprise a plurality of spaced apertures that are aligned along a generally straight line.

5. A safety device as claimed in claim 3 or claim 4 wherein the leg, arm or plate extends generally perpendicularly to the base.

6. A safety device as claimed in any one of claims 2 to 5 wherein the second housing part comprises a first wall that, in the closed position, extends outwardly from the base and a second wall that covers the actuator when in the closed position.

7. A safety device as claimed in claim 6 wherein the second housing portion comprises a flange or a lip extending from the second wall, the flange or lip including the plurality of apertures.

8. A safety device as claimed in claim 6 wherein the plurality of apertures comprise a plurality of spaced apertures that are aligned along a generally straight line.

9. A safety device as claimed in claim 7 or claim 8 wherein the flange or lip extends generally perpendicularly to the second wall.

10. A safety device as claimed in any one of the preceding claims wherein the second housing part comprises a cover.

11. A safety device as claimed in any one of the preceding claims wherein the housing further comprises a stop member that is located adjacent to the actuator when the second housing portion is in the closed position.

12. A safety device as claimed in claim 11 wherein the stop member comprise a plate, comprise a projection or an abutment extending from the second housing portion.

13. A safety device as claimed in any one of the preceding claims wherein the housing presents a closed front to personnel when in the closed position.

14. A safety device as claimed in claim 13 wherein the housing has open sides.

15. A safety device as claimed in claim 13 wherein the housing has closed sides.

16. A safety device as claimed in any one of the preceding claims wherein the second housing portion is hingedly connected to the first housing portion.

17. A safety device as claimed in any one of claims 1 to 15 wherein the second housing portion is slidable relative to the first housing portion, or the second housing portion is positioned relative to the first housing portion in the closed position and the second housing portion is connected to or locked into position with the first housing portion.

18. A safety device as claimed in any one of the preceding claims wherein the first housing portion includes one or more fixing apertures to enable the first housing portion to be fixedly mounted relative to the actuator.

19. A safety device as claimed in any one of the preceding claims wherein the first housing portion and the second housing portion are made from a suitable rigid material.

20. In combination, an electrical switch and a safety device as claimed in any one of the preceding claims, the first housing portion being fixedly mounted relative to the switch or to a member to which the switch is mounted.