Abstract:
An enclosure for containing electrical components and for recessing into and fixing to a surface is disclosed. The enclosure has a box and a flange extending the box adjacent an opening in the box. The flange has an aperture in each corn to receive a fixing screw. A first seal extends around the box on a rear surface of the flange. A lid covers the opening and the flange and touches the first seal. A second seal extends around the opening and engages the lid and the body. Lid screws fix the lid to the body. The apparatus provides an easy to clean and completely sealed enclosure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to United Kingdom Patent Application No. 1512970.3, filed Jul. 22, 2015, the entirety of which is hereby incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to an electrical component enclosure and relates particularly, but not exclusively, to an enclosure for containing electrical components which is recessed and fixed to a wall. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is extremely commonplace for electrical components, such as switches, to be recessed into walls. In industrial premises where cleanliness is paramount, such as the food and beverage preparation and pharmaceutical industries, it is particularly important that all surfaces and switches are easily cleaned and more preferably provide a substantially waterproof seal protecting the electrical components within the enclosure from any engagement with water. 
         [0004]      FIG. 1  shows an example of a waterproof enclosure of the prior art. The enclosure  10  is recessed into an opening  12  in a wall  14  covered with tiles  16  which are stuck to the wall  14  using a layer of adhesive  18 . The enclosure  10  includes a metal box  20  which is entirely contained within the opening  12  and is generally fixed to a surface of the opening  12  by an adhesive or a screw (not shown) extending in to wall  14 . The box  20  has a pair of lugs  22  which have threaded apertures to receive bolts  24 . The bolts extend through a front plate  26  which carries a component such as a button switch  28 . The bolts  24  pull the front plate  26  towards the metal box  20  and a bead of sealant  30  extends around the front plate  26 , adjacent its perimeter, thereby sealing the enclosure relative to the wall in preventing water from entering the enclosure. 
         [0005]    The installation of this enclosure  10  will only provide a waterproof seal if the bead of sealant  30  is correctly applied. A number of factors affect the quality of this seal including the quality of the bead of sealant applied by the installer, which is at least in part dependent upon the installer&#39;s experience. Furthermore, over tightening of the bolts  24  can lead to damage to the seal  30 , distortion of the front plate  26  or dislodging of the box  20  from its fixing to wall  14  making the whole enclosure  10  vulnerable to removal from the opening  12 . It is also the case that to the wall by the sealant. As a result, if a pulling force is applied to the enclosure it can become partially dislodged from the wall thereby damaging the seal. Furthermore, if the cover plate is removed, for example for inspection or maintenance, the sealant  30  must be completely removed from the front plate  26  and a new bead of sealant applied. 
         [0006]    Preferred embodiments of the present invention seek to overcome the above described disadvantages of the prior art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    According to an aspect of the present invention there is provided an enclosure for containing electrical components and for recessing into and fixing to a surface, the enclosure comprising: a body including a box defining a volume and having at least one open portion allowing access to said volume, the body also including a flange extending from said box adjacent said opening portion, said flange having a plurality of fixing apertures extending therethrough for receiving a fixing device to fix said enclosure to a surface with said box extending at least partially through said surface; a first seal extending around said box and engaging a first side of said flange and in use said surface; a lid for covering said opening, the lid having a substantially planar portion and edge portions extending over said flange and engaging said first seal; a second seal extending around said opening and engaging said lid and said body; and a lid fixing device for fixing said lid to said body and applying a compression force to said second seal. 
         [0008]    By providing seals formed as part of the enclosure the advantage is provided that the quality of the seal, that is its capacity to prevent water ingress, is much less dependent on the experience and ability of the installer than enclosures of the prior art. Furthermore, the integrity of the seals can be tested for each enclosure prior to installation, that is during manufacture, thereby significantly reducing the likelihood of installer error leading to an unsealed enclosure. By having the edge portions of the lid engaging the first seal, the advantage is provided that the lid is sealed twice relative to the inside of the enclosure. As a result, the first seal, which is external to the formed enclosure and is contactable from the outside of the enclosure can be formed from a first sealing material and the second seal formed from a second sealing material. The first sealing material can meet requirements of being externally exposed, for example meeting certain regulatory authority standards, whilst the inner seal can have other properties providing a better seal. 
         [0009]    Because the fixing device for fixing the enclosure to the wall, typically screws, are covered by the lid (because the lids covers the flange) the advantage is provided that if the holes formed into the walls are not quite precise, the fact that the screws extending into these holes may not fit perfectly with the flange does not matter since the flange is covered by the lid. If this were not the case, the incomplete engagement of the bolts with the flange could risk the creation of dirt traps which is undesirable in clean environments. Furthermore, in order to ensure a secure installation it is not uncommon for the box fixing device (the previously mentioned screws) to be damaged during installation by over tightening which can again lead to the creation of dirt traps. The only externally exposed fixings are the lid fixing device which do not need to be very tightly fitted to ensure therefore less likely to be damaged during installation. 
         [0010]    In a preferred embodiment the opening is formed in a surface of said box, said surface forming a frame at least partially around said opening. This provides the advantage that the lid fixing device is able to extend into the frame and therefore contained within the volume of the enclosure. 
         [0011]    In another preferred embodiment the lid fixing device comprises bolts extending into threaded openings. 
         [0012]    In a further preferred embodiment the threaded openings are formed in said frame. 
         [0013]    In a preferred embodiment the threaded opening comprises a recess not in communication with said volume. This ensures that there is no route of water ingress from the outside of the lid to the inside of the body of the enclosure. The enclosure may further comprise components and these components may in turn comprise switches. The second seal may be fixed to said lid. By fixing the second seal to the lid the advantage is provided that correct installation of the second seal is ensured and not left to the skill of the installer. The first seal preferably comprises a silicon rubber and the second seal preferably comprises neoprene. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Preferred embodiments of the present invention will now be described, by way of example only, and not in any limitative sense with reference to the accompanying drawings in which: 
           [0015]      FIG. 1  is a sectional view of an enclosure of the prior art; 
           [0016]      FIGS. 2 and 3  are perspective views of an enclosure of the present invention prior to installation; 
           [0017]      FIGS. 4 and 5  are perspective close up views of a portion of an another enclosure of the present invention prior to installation; and 
           [0018]      FIGS. 6 to 12  are a series of examples of installed enclosures of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0020]    The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto. 
         [0021]    Referring to  FIGS. 2 to 12 , an electrical enclosure  50  is provided for containing electrical components such as wires and cables, connectors, switches and the like. The enclosure is designed to be fixed to and recessed into a surface such as a wall. The enclosure  50  has a body, indicated generally at  52 , which is formed from a box  54  and a flange  56 . The box shown in the embodiments in  FIGS. 2 to 5  is a cuboid with an opening  58  in the face adjacent the flange  56 . The opening  58  acts as an open portion allowing access to a volume defined by the internal surfaces of the faces of box  54 . The flange  56  extends around the whole face of the box  54  which has opening  58  in it and therefore has dimensions greater than those of that face of box  54 . For fixing apertures  60  in the corners of the flange  56  are provided so that a fixing device, in the form of fixing screws (not shown) can be used to fix the flange, and therefore the enclosure  50 , to a wall or other surface. 
         [0022]    The enclosure  50  also includes a lid  62  which is sized to be large enough to cover the face of box  54  with the opening  58  as well as covering the flange  56 . The lid  62  has a substantially planar surface  64  and in the embodiment shown in  FIGS. 2 and 4  a component, in the form of switching apparatus  66  is provided extending from the substantially planar surface  64  are edge portions  68  which extend transverse from the planar surface with the end edge portions  68   a  extending roughly perpendicular to the planar surface  64  and the top and bottom edge portions  68   b  extending at roughly 45°, thereby preventing objects such as pens being left resting on the enclosure. 
         [0023]    The enclosure  50  is provided with two seals. The first seal  70  extends around the box and engaging the flange  56 . As a result the first seal  70  is shaped very similarly to the flange  56  and engages a reverse side of the flange, which is obscured from view in the drawings by the seal. When the enclosure  50  is in use the first seal  70  is pressed into engagement with the flange  56  and the surface of the wall into which the enclosure is fixed. The first purpose of the first seal is therefore to prevent water ingress into the cavity into which the enclosure has been fixed. It should be noted that the box  54  is watertight and would not allow any water in the cavity behind the box to enter the volume of the enclosure but it is still advantageous to ensure that no water enters the cavity as it may damage the cavity or may seep out of the cavity having been contaminated whilst in the cavity. The first seal is preferably made from a material which has good sealing and excellent hygiene properties such as a silicone rubber. 
         [0024]    A second seal  72  is also provided and this extends around the opening  58  and engages both the lid  62  and the body  52 . If the opening  58  is provided as a large aperture in a face of box  54  this will generally result in the remainder of that face forming a frame. It is therefore preferable that the second seal  72  extends around the opening  58  engaging this frame. As an alternative, the second seal  72  could extend around the opening  58  by engaging the flange  56  on the opposing surface to the surface engaging the first seal  70 . To ensure that the second seal is in the correct position it is glued into engagement with the lid. Because the second seal  72  will not come into engagement with anything outside the enclosure its hygiene properties are not as significant as those of the first seal  70 . As a result, the second seal can be formed from any suitable sealing material and neoprene is a good example as it has excellent sealing properties but its somewhat foam-like structure means that it is less suitable for use where hygiene is of paramount concern. 
         [0025]    In order to fix the lid  62  to the body  52  a lid fixing device are provided. These are in the form of bolts  74  which fix into threaded apertures (not shown) which are formed in the frame extending around opening  58 . These threaded apertures are preferably recesses which are not open into the volume of box  54  (that is they are not in communication with the volume of the box) and therefore in the unlikely event that water could, through capillary action, move around the thread of the bolts  74  it would be trapped in these recesses and could not enter the volume of the enclosure. 
         [0026]    In the examples in  FIGS. 6 to 11  various different forms of switch apparatus are shown. In  FIG. 12  a blank enclosure is shown with no component extending through the lid  62 . 
         [0027]    Installation and operation of the enclosure  50  will now be described. For installation into a solid wall a recess is formed in the wall having dimension slightly larger than the box  54  so as to accommodate the box. If the enclosure  50  is being installed into a sheet material, such as plasterboard or a metal sheet material, and aperture is cut into the sheet material sized to receive the box  54  but smaller than the flange  56 . Fixing holes are also formed into the surface onto which the enclosure  50  is to be installed and these are located using the aperture  60  in the flange. 
         [0028]    If wires and or cables are two extend through the enclosure  50  these will typically be installed through aperture is cut into the box  54  and sealed using cable glands prior to installation. 
         [0029]    The body  52  of enclosure  50  is brought into engagement with the aperture or recess in the wall such that the first seal  70  is engaged with the flange  56  and the surface of the wall and with the fixing apertures  60  aligned with the recently drilled holes in the wall surface. Screws are then used to fix the enclosure to the wall with the screws extending through the fixing apertures and into the holes in the wall, which will typically have retaining plugs placed therein. When enclosure  50  is being fixed to a sheet material specifically designed plugs may be used or other fixing device with legs to engage the inside of the sheet material may also be used. It does not matter if the screws extending through the fixing apertures  60  are damaged during installation or are not perfectly aligned leaving small dirt traps since they will be covered by the lid  62 . 
         [0030]    Once the body  52  is securely fixed to the wall the lid  62  can be introduced. Firstly, the cables can be connected to the switch  66  or other component forming part of the enclosure and then the lid  62  is brought into engagement with the body  52  so that the bolts  74  are aligned with the threaded recesses in the frame around the opening  58 . The bolts  74  are then tightened which compresses the second seal  72  between the inner surface of lid  62  and the frame around the opening  56  in body  52 . At the same time, the edge portions  68  of the lid  62  come into engagement with the first seal  70  as they extend around the periphery of the flange  56 . This provides a second form of sealing for the first seal as it prevents water ingress into the space between the edge portion  68  of lid  62  and the second seal  72 . Because this seal is between the edge portion  68  and the first seal  70  it may not be perfect, in particular if the surface of the wall in which the enclosure is engaged has imperfections. However, there will generally be two levels of sealing function between the exterior of the enclosure and the internal volume of the body the first being provided by the first seal  70  (which is also sealing the recess into which the enclosure is sat) and the second by the second seal  72 . Because the bolts  74  extend into threaded apertures they do not need to be tightened with excessive force to provide sufficient sealing required and is therefore very unlikely that they will be damaged during installation. 
         [0031]    It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the protection which is defined by the appended claims. 
         [0032]    While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims.