Patent Publication Number: US-2011052345-A1

Title: Fastening means and articles formed using the same

Description:
The invention to which this application relates is a fastening means of a type which can be used to secure a first article to another article, typically by rotating the fastening means to engage a thread formed in the same with an aperture which may be threaded in said article. 
     There are numerous forms of fastening means currently available which allow one item to be secured to another item. A common problem which is encountered is that the fastening means themselves, and/or tools used to secure the fastening means in position, can cause damage to the article or articles which are being secured together. Furthermore, in many instances, in particular during mass manufacturing processes, the articles themselves may be susceptible to damage. In particular, relatively expensive surface finishes or surface finish effects on said articles are susceptible to damage. 
     As a result of this problem, it is commonly the case that at least part of said articles may be provided with a protective coating which is maintained in position during the manufacturing process and is only removed at the time of final packaging. While it is found that the provision of these coatings does greatly reduce the risk of damage to the article, the process of having to remove the protective coating adds time to the manufacturing process. This is particularly the case in circumstances where the protective coating is required to be removed and parts of the same are trapped in position by fastening means. This then renders the protective coating adjacent the fastening means difficult and time consuming to remove so that it is no longer visible and therefore adds additional time to the overall manufacturing procedure which represents additional costs, can represent a bottle neck in the manufacturing process and can also be frustrating to the operators. Indeed it is also possible that the attempts to remove the trapped protective coating, can cause damage to the very same article surfaces which the protective coating was originally provided to protect. 
     This problem has been identified by the applicant and the aim of the present invention is therefore to provide an ability to reduce these problems whilst, at the same time, ensuring that the visual appearance of the articles is not adversely affected. 
     In a first aspect of the invention, there is provided a fastening means, said fastening means having a shaft, a head portion connected to one end of the shaft, said head portion having a top face and an opposing underside, said underside moving towards at least one component as the fastening means is driven into the same and wherein said fastening means is provided with a formation to pierce into at least one layer of material on said component when the formation comes into contact with said component. 
     In one embodiment, the said formation is provided to rotate along with the rotation of the head portion as the fastening means is driven into position so as to pierce through and define a portion of the said at least one layer of material which is substantially separated from the remainder of the layer. 
     Typically the formation is positioned on the underside of the head of the fastening means and the portion of the material underlies the head and is smaller than the area of the head in plan, so that the separated portion is not externally viewable. 
     In one embodiment, the formation is provided as an integral part of the head and typically the head, formation and shaft are provided as integral parts. 
     Typically the formation has a leading edge or tip, said leading edge being placed at a distance from the underside of the head, and in advance of the same with respect to the direction of driven movement, such that the leading edge or tip contacts the layer of material in advance of the underside of the head. This also ensures that there is a sufficient gap to allow the layer of material which underlies the periphery of the head to be slid away and removed. 
     In one embodiment the formation defines a circular ring and the area of the head which lies between the formation and the shaft is recessed such as to receive and accommodate the separated portion of the layer of material therein. Typically the depth of the recess from the leading edge or tip of the formation is less than the distance from the leading edge or tip to the underside of the head. This arrangement means that even if the formation is moved so as to pierce into the component into which the same is driven there will still be a sufficient gap between the underside at the periphery of the head and the component to allow the layer of material from which the portion has been separated, to be removed. 
     In one embodiment, the head portion is provided with a drive formation which may be provided on the top face and/or side walls of the head portion for the engagement of a drive tool therewith to allow the fastening means to be rotatably driven into a fastening position. 
     In one embodiment, the shaft of the fastening means is threaded. 
     In one embodiment, at least one layer of material is pierced and a disc is formed in the same. Typically this layer is a protective coating layer and, once the fastening means is placed in position, the protective coating layer surrounding the fastening means can be easily removed as the same is free from the fastening means and is separated from the portion of the protective coating layer which is trapped in position by the head of the fastening means. 
     In one embodiment, the formation extends around the underside of the head of the fastening means or alternatively, can be provided as a projection at one point or a plurality of projections at spaced points on the underside of the head. 
     In one embodiment, the fastening means is provided as a single part component. 
     In one embodiment, the components to be joined together are a base casing for an electronic device and a cover for the same which, when joined together, form the article in the form of an outer housing. In one embodiment, the cover is provided with a particular surface coating which is required to be protected during manufacture and to which the protective coating layer is applied and which is only removed at the end of the assembly procedure, and typically after testing has occurred, which testing typically requires the fastening means to already have been inserted in position. 
     In one embodiment the fastening means pierces through a decorative surface coating to contact a conductive layer of material. In this embodiment of the invention the fastening means is used to provide an effective ground earth connection for the article which is formed. 
     In a further aspect of the invention there is provided a method for forming an article using fastening means to fasten components of the article together, said fastening means having a head connected to a shaft portion and a formation is provided on the underside of the head portion thereof, moving said fastening means into a fastening position for said components and continuing to move said fastening means so that the formation on the underside of the head, contacts with at least one component to pierce through at least a layer of material on the same. 
     In one embodiment the piercing through of the at least one layer is performed to separate a portion of the layer underlying the head, from the remainder of the layer. This, in one embodiment, allows the subsequent removal of the said remainder of the layer. In one embodiment the layer is a protective coating layer. 
     In one embodiment, the formation is provided so as to form a disc in a protective coating layer which is separated from the reminder of the protective coating layer. 
     In one embodiment the formation is caused to pierce through at least one layer of material to make contact with a further layer underlying the same and allow a ground or earth connection to be achieved. 
    
    
     
       Specific embodiment of the invention are now described with reference to the accompanying drawings wherein; 
         FIG. 1  illustrates an article with components joined together using fastening means in accordance with one embodiment of the invention; 
         FIG. 2   a  illustrates parts of said article of  FIG. 1  with the fastening means in the first position; 
         FIG. 2   b  illustrates the parts of the article of  FIG. 2   a  with the fastening means in a fastening position; and 
         FIGS. 3   a - d  illustrate one embodiment of the fastening means. 
     
    
    
     Referring firstly to  FIG. 1  there is illustrated a broadcast data receiver  2  (also referred to as a set top box) which is now described, in a non limiting manner, as an example of an electrical article suited for potential use of the fastening means in accordance with the invention. 
     The broadcast data receiver is provided to receive data from a remote location and to process the same and, typically, to allow user services such as for example television and radio programs to be generated. The article comprises a front panel  4  located on a base  1  and onto which a cover  6  is secured. In this case the cover  6  has an external surface which has an attractive or decorative appearance. In one known form, the cover is coated with a material, which is relatively susceptible to damage during manufacture of the article. As a result of this, the external surface of the cover is provided with a protective coating layer  8  during the manufacturing process. The protective coating layer is maintained in position during manufacturing, assembly and testing until the final packaging stage of the article, at which stage, the protective coating layer is required to be removed. Removal of the protective coating layer is relatively straight forward by peeling the same, except at those areas where the same is trapped in position under the heads of the respective fastening means which are driven through apertures in the cover and base to join the same together. The fastening means are typically located at the edges of the cover and base, as shown in  FIG. 1 , where the fastening means  20  are located at the rear edge  10  of the cover and edge  12  of the base. The fastening means are typically required to be driven into position prior to the removal of the protective coating for assembly and/or testing requirements. 
     Conventionally, the provision of these fastening means with their heads on the protective layer means that portions of the protective layer adjacent thereto are effectively trapped between the fastening means head and the component and it can become difficult for the operator to be able to remove all parts of the material so that the material is no longer viewable. This represents a significant bottle neck in the manufacturing process. 
     Referring now to  FIGS. 2   a  and  b , there is illustrated a cross sectional view along line A-A of a fastening means being moved into position. There is shown the edge  12  of the base overlaid by the edge  10  of the cover  6  of the article. In  FIG. 2   a  the cover comprises layers of steel  3 , acrylic  5  and PVC coating  7  overlaid by the protective coating layer  8 . An aperture  11  is provided into which a fastening means  20  in accordance with the invention is to be secured. 
     The fastening means is shown in one embodiment in more detail in  FIGS. 3   a - d  and comprises a threaded shaft  22  connected to a head portion  24  which is provided with a drive formation  26  to allow the fastening means to be engaged by a tool and driven into the fastening position shown in  FIG. 2   b.    
     On the underside or under face  30  of the head portion, there is provided a formation  28  in accordance with the invention. This formation is formed such that when the fastening means is moved downwardly into position onto the components, to the position shown in  FIG. 2   b , the formation cuts into at least the protective layer material  8  to pierce the same. Continued rotation of the fastening means as it is being driven means that preferably, an annular disc  32  of the protective coating layer is formed which is separated from the remainder of the protective coating layer  8  which lies around and to the outside of the formation of the fastening means and which can easily be removed as indicated in  FIG. 2   b  by arrows  34 . 
     The separated annular disc  32  lies within the recess portion  36  which is formed on the underside of the head and which lies within the area defined between the shaft  22  and the formation  28  and in which recess the annular disc is retained. Typically the depth  40  of the recess from the leading edge or tip  41  of the formation is less than the distance  42  from the leading edge or tip to the underside  30  at the periphery of the head. This arrangement means that even if the formation is moved so as to pierce into the component into which the same is driven there will still be a sufficient gap  43  between the underside at the periphery of the head and the component to allow the layer of material  8  from which the portion has been separated, to be removed. 
     In one embodiment the fastening means is driven in to a sufficient depth such that the formation pierces through a number of layers to contact with the conductive, steel layer  3 . In this way a ground connection can be achieved via the fastening means which is effective and which is secured as a permanent ground connection thereby aiding the manufacture and performance of the article. It should therefore be appreciated that this is in itself a significant advantage and thus the fastening means may be used even when there is no protective layer used on the component into which the fastening means is being driven. In this embodiment the fastening means is provided to be used solely as a means for creating a good ground connection. 
     It will be appreciated that in certain instances, the piercing may not be sufficiently uniform so as to form an annular disc but it should equally be appreciated that any manner in which the protective coating layer underlying the head of the fastening means is separated from the remainder of the protective coating layer, is achieved, is advantageous. Thus, with the fastening means in position, the remainder of the protective coating layer can then be removed and there is no need to remove particular portions from the area adjacent the fastening means or underneath the same as the protective layer around the fastening means is detached therefrom. This therefore means that although a portion of the protective coating layer will remain in position under the fastening means head, the same is not visible and therefore does not detract from the appearance of the article.