Field of the Invention

[0001] The present invention relates to the field of security devices. In particular, it relates to a device for preventing the unauthorized use of an appliance or other piece of electrical equipment.

Background of the Invention

[0002] A commonly occurring requirement is to prevent the unauthorized use of an item of electrical equipment of the type having power cable terminated in a plug that can be plugged into a mains power supply.

[0003] In industrial settings, for example, items of equipment may be identified as faulty, and pending repair it may for safety reasons be desired to prevent their use. Some equipment, such as sophisticated instrumentation, may be intended only for use by people trained and competent to use it.

[0004] In domestic situations, it may be desired to prevent an appliance (such as a computer game device, a personal computer, or an entertainment device, from being used by children or other family members at particular times, or at all.

[0005] Various solutions have been devised for achieving these objectives, and one class of these involves securing to, or over, a mains plug of the equipment a device that prevents the plug being plugged into a power socket. The present invention is in this class and is intended to allow access to the plug to a holder of a key.

[0006] Some devices of this general type are sophisticated, expensive and unsightly, and are in particular unsuitable for domestic applications. A device according to the invention can be compact, conveniently made and comparatively inexpensive as well as secure. Accordingly, it represents a useful contribution to the choices available to consumers, especially domestic consumers.

Summary of the Invention

[0007] According to the invention there is provided an electrical equipment lockout device including: a container assembly having a plurality of parts movable relative to each other to define closed and open conditions of the container; and a lock assembly operable by a user to lock the parts together in relative positions corresponding to the closed condition, wherein in the closed condition of the container the parts define an internal space having a cable opening to the exterior of the container, so that a power plug of an item of electrical equipment can be held captive in the internal space with a cable terminated in the plug passing through the cable opening to the exterior of the container.

[0008] In a preferred embodiment of the invention, the plurality of parts includes a first part and a second part with the second part being rotatable between positions corresponding to the open and closed conditions about a rotation axis defined in the first part; and the rotation axis passes through the internal space.

[0009] It is particularly preferred that the rotation axis passes through the first opening.

[0010] The internal volume may be included in a cavity defined within the first part, said cavity having an opening to the exterior of the first part that includes the cable opening and that when container is in the closed condition is partially closed by said second part leaving open the cable opening. In a convenient arrangement, the second part is captive in said cavity of the first part.

[0011] Preferably, said cavity has at least one surface that is an inwardly facing partial surface of revolution centered on the axis of rotation and wherein said second part bears against said at least one surface. That is, in effect, the interior of the cavity acts as a bearing to constrain movement of the second part to rotation about the rotation axis in the first part.

[0012] Where the second part is captively held in the cavity of the part, said first part is preferably an assembly including two components that are fixedly secured to each other and that jointly define said internal cavity. The two components may be permanently secured to each other. For example, the first and second parts may be made by injection moulding in suitable plastics materials, with the first part having two parts

that are ultrasonically welded together with the second part positioned to be held in the cavity thus formed. If the assembly is made of cast or machine metal the joining of the aforesaid parts may be made using a threaded junction of male thread on one part and female thread on the other part that is secured in place by thread adhesive or by means of a mechanical depression that prevents the threaded joint from moving by upsetting the junction of the meshing threads.

[0013] The lock assembly preferably includes a key-operated lock assembly secured to said first part and adapted in a locked condition to position and hold a cam to prevent rotation of said second part relative to said first part. The lock assembly may conveniently be positioned approximately on the said rotation axis. The direction of key insertion into the locking means may be parallel to said rotation axis. [0014] Preferably, a tether is attached to the device to allow the device to be secured to the cable when not in use. Even more preferably, the tether has a locking mechanism that uses the same key as the locking mechanism for the device.

[0015] Other and further advantages and features of the invention will be apparent to those skilled in the art from the following detailed description thereof, taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0016] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which like numbers refer to like elements, wherein:

Figure 1 is a perspective view of a lockout device according to the invention, shown in an "open" condition ready for use;

Figure 2 is a further perspective view of the device as shown in Figure 1 , with a plug and power cable positioned in the device;

Figure 3 is a perspective view of the device shown in Figure 1, now in a "closed" condition;

Figure 4 is a further perspective view of the device shown in Figure 1, in a "closed" condition

Figure 5 is an exploded view of the device shown in Figure 1 ;

Figure 6 is a cross-sectional view of the device shown in Figure 1 , taken at the station "AA";

Figure 7 is a cross-sectional view of the device as shown in Figure 6, taken at the station "BB"; and

Figure 8 is a perspective view of the device with an attached tether; and

Figure 9 is a cross-section of the locking end of the tether.

Detailed Description of the Preferred Embodiments

[0017] Figure 1 shows a lockout device 10 according to the invention, hi Figurel, device 10 is shown in an "open" condition, and can be seen to have a body 15 with an internal volume 11 into which can be placed a mains power plug 12 and part of a cable 13 that is terminated in the plug 12. Figure 2 shows plug 12 and cable 13 placed in the volume 11 of device 10, device 10 still being in open condition. An opening 14 in body 15 of device 10 allows placement of the plug 12 and cable 13 in volume 11 in the position shown. Figure 3 shows device 10 now in "closed" condition, with the plug 12 and cable 13 in the same positions as in Figure 2. Opening 14 has been closed by a member 16, save for one portion of opening 14 that remains open and acts as a cable opening 17. Cable 13 extends outward though cable opening 17.

[0018] Member 16 is captively held in body 15 of device 10 and is rotatable relative to body 15 about a rotation axis 18 defined in body 15 between the position shown in Figures 1 and 2 and the position shown in Figure 3. A key-operable lock mechanism 19 is secured within body 15 and when in a locked condition can hold member 16 in the position shown in Figure 3, as described further below.

[0019] In the preferred embodiment of the invention shown in Figures 1 to 3, it will be noted that rotation axis 18 passes through cable opening 17, with cable 13 extending substantially along axis 18.

[0020] Figures 5 to 7 show the internal arrangement of device 10. Body 15 is formed by permanently securing together two components, namely a shell 20 and base 21. Opening 14, including cable opening 17, is formed in shell 20. Shell 20 defines an internal cavity 22 and also has an opening 23 and an annular end face 24. Internal surface 25 of shell 20 is circular in cross-section (save for the presence of opening 14), centered on rotation axis 18. Base 21 has an annular end face 26 and an outer wall 27. A tubular formation 28 extends inward from wall 27 in an axial direction, i.e. along rotation axis 18. Radial strengthening ribs 55 extend between tubular formation 28 and wall 27. [0021] Although not essential to operation of device 10, cutaways 50 are formed in wall 27 with a web 51 therebetween. Web 51 has a hole 52 therethrough to allow for the attachment of identification tags (not shown) or the like.

[0022] The primary use for hole 52 is the attachment of a tether 70 as shown in Figure 8. The tether 70 can be used to attach the device 10 to the cable 13 to prevent the device from being lost or misplaced while not in use. Ideally, tether 70 has a locking mechanism 72 that is used to permanently secure the device 10 to the cable 13. Alternatively, the locking mechanism 72 can be operable to removably secure the device 10 to the cable 13 in situations where permanent securing is undesirable, such as with a power tool at a job site. In such a case, it may be preferable to have the locking mechanism 72 on the tether 70 use the same key as the lock mechanism 19 on the device 10.

[0023] The tether 70 should be made of a suitable resilient material, such as a braided steel cable. In the example shown in Figure 9, the tether 70 has locking mechanism 72 attached a short distance from the end 78 of the tether 70. The end 78 of the tether 70 has a plug 76 which is inserted into a slot 74 in locking mechanism 72 after tether 70 is wrapped around cable 13 (not shown). The plug 76 is then held in place by spring clips 77 or a similar mechanism. The resulting enclosed area 80 should be of sufficient size to allow cable 13 to move freely within the area 80, while remaining small enough to prevent passage of the plug 12 (not shown).

[0024] A similar locking mechanism can be used to attach tether 70 to the device 10 through hole 52 as shown in Figure 8, with the result that tether 70 has a locking mechanism 72 at both ends. Alternatively, tether 70 can be integrally formed as part of the device 10 during assembly, such that tether 70 only requires a locking mechanism at one end.

10025] In manufacturing of device 10, shell 20 and base 21 are preferably formed by injection moulding in plastics or die cast metal, including metals such as aluminum and zinc (although this is not to preclude other suitable possibilities). Shell 20 and base 21 are subsequently mated with their respective end faces 24 and 26 abutting each other and permanently joined together by ultrasonic welding or a suitable adhesive, or in the case of a metal assembly, by means of threaded junction of the two parts, for example. 10026] Before mating of shell 20 and base 21, member 16 is placed in cavity 22 of shell 20, via opening 23. After shell 20 and base 21 are joined, member 16 is captive within cavity 22. Member 16 has an external surface 29, that conforms in shape with, and at this stage lies closely adjacent to, internal surface 25 of shell 20, so that member 16 is rotatable within cavity 22 about rotation axis 18. Member 16 has an end wall 30 that is perpendicular to axis 18.

[0027] Member 16 is captive within cavity 22 of shell 20 because opening 14 is so proportioned that member 16 cannot be withdrawn therethrough. However, to further secure against withdrawal by force of member 16 from cavity 22, a partial collar 31 having a surface 33 that is a sector of a cylinder is formed in shell 20 at the end opposite base 21. As best seen in Figure 6, member 16 is shaped and proportioned to lie between partial collar 31 and wall 32 of shell 20 at the end. As member 16 is rotated between its closed and opened positions, surface 33 acts as a bearing surface for member 16. [0028] Partial collar 31 partly defines a notch 34 that is part of opening 14 and that, when member 16 is rotated to its closed position, becomes the cable opening 17. [0029] Lock mechanism 19 is of known type, having an outer cylinder casing 40 and barrel 41 rotatable therein. By operation of tumblers (not shown) in and extending transversely across barrel 41, barrel 41 is prevented from rotating within cylinder casing 40 except when a correct key (not shown) is inserted into barrel 41. Such a mechanism and function are well known and need not be described in detail herein. A shaped driver

end 42 is secured to and rotatable with barrel 41 and engages with a co-operating opening in a formation 43 integrally formed in member 16, so that when barrel 41 cannot rotate, member 16 cannot rotate. This condition corresponds to the closed condition of device

10, in which opening 14 is closed (save for cable opening 17) by member 16.

[0030] It is to be noted that driver end 42 is preferably star shaped, in order to distribute the torque from lock mechanism 19 evenly into formation 43. When formation

43 is of plastic materials this can be important to prevent deformation of formation 43 and disabling of lock mechanism 19 thereby.

[0031] To withdraw plug 12 from device 10 in its closed condition, the correct key is inserted into barrel 41, so that barrel 41 and member 16 become free to rotate together, and member 16 is then rotated to its open position (see Figure 2). In this position member 16 is wholly with cavity 22 of body 15 and prevents no obstacle to withdrawal of the plug 12 through opening 14. Cable opening 17, in this position of member 16, becomes notch 34, and cable 13 can be withdrawn therefrom at the same time.

[0032] Many variations can be made to device 10 without departing from the spirit or scope of the invention. For example, the egg-like shape of device 10 could be altered.

However, the shape of device 10 as shown is such as to compactly surround plug 12 and cable 13 and is attractive in appearance and economical of materials.

[0033] The device 10 could of course be made in a range of shapes and sizes to accommodate different plug designs and cable sizes.

[0034] This concludes the description of a presently preferred embodiment of the invention. The foregoing description has been presented for the purpose of illustration and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching and will be apparent to those skilled in the art. It is intended the scope of the invention be limited not by this description but by the claims that follow.