Abstract:
A connection fitting ( 10 ) for a pipe, including a tubular body ( 12 ), an O-ring ( 14 ) mountable on outer side of tubular body ( 12 ), a substantially tubular collet ( 16 ) having a first end and a second end and having a memory, a substantially annular and resilient grab ring ( 20 ) for gripping the outer side of a pipe inserted into the collet ( 16 ), a substantially tubular spacer ring ( 22 ) locatable on the free side of the grab ring ( 20 ), a collet retainer ( 18 ), and a tubular protection ring ( 24 ) locatable within the spacer ring ( 22 ), wherein when the collet retainer ( 18 ) engages with the collet ( 16 ) and causes the collet ( 16 ) to lock onto the tubular body ( 12 ) apertures ( 66 ) in the collet retainer ( 18 ) permit portions of the protection ring ( 24 ) to be seen after connection of a pipe to the connection fitting ( 10 ) is completed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to plumbing and gas pipe connections. In particular the present invention relates to readily assembleable push fit connection fittings or couplings, in which a pipe, tube or conduit (hereinafter referred to as a tube) can be pushed into the connection fitting and be retained connected to the connection fitting by internal elements of the connection fitting. 
       BACKGROUND OF THE INVENTION 
       [0002]    There are a considerable number of connection fittings or couplings for joining pipes or tubes to each other, for example, or to join appliances or accessories to tubes or pipes. In many instances these connection fittings are bulky and use a considerable amount of materials because of the need to provide room within the connection fitting for the assembly of the component. The connection fitting itself may be difficult to install because of its size and the space required to accommodate it. 
         [0003]    Additionally, some connection fittings require the use of tools and/or additional components to properly seal or make secure the connection between the connection fitting and the tube or pipe. This can also create significant problems where space for the connection fitting is limited. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention aims to ameliorate some or all of the aforementioned problems in providing a quick connect/disconnect connection fitting that grips the outside of a tube or pipe and seals on the inside of the pipe. It is intended that the connection fitting of the invention can be attached to or incorporated in other in-lined devices, such as valves and other equipment, as well as a plurality of connection fittings being incorporated in in-line joiners, whether straight-line, angle, or split, such as key-joints or Y-joints, or otherwise. 
         [0005]    According to one aspect of the invention there is provided a connection fitting for a tube or pipe, including a tubular body having a first end and a second end, the bore of which extends from the first end towards the second end and which may be blind at the second end, the tubular body being provided on its outer side with a circumferential channel for receiving an O-ring and means for engaging with a collet, the outside diameter of the tubular body being receivable within the tube or pipe to which the connection is to be made; an O-ring mountable in said circumferential channel, the O-ring being adapted to enter into a sealing relationship with the inner side of a tube or pipe as the connection with that tube or pipe is effected; a substantially tubular collet having a first end and a second end and having a memory, so that the cross-section of portions of said collet are reversibly alterable, which collet engages by mean of engaging means provided adjacent its second end with engaging means provided on the outer side of the tubular body; a substantially annular and resilient grab ring for gripping the outer side of a tube or pipe inserted into the collet, the grab ring being locatable adjacent the first end of the collet; a tubular spacer ring locatable on the free side of the grab ring adjacent the first end of the collet; a collet retainer provided with engaging means which engages with the collet and which causes the collet to lock to the tubular body, said collet retainer locating the grab ring and the spacer ring adjacent the first end of the collet; and a tubular protection ring locatable within the spacer ring, the outside diameter and inside diameter of which protection ring at its first end are equal to the outside diameter and inside diameter of the tube or pipe to be connected to the connection fitting, the inside of the protection ring being chamfered at its second end to assist in the proper insertion of the tube or pipe into the connection fitting and onto the tubular body. 
         [0006]    The outer surface of the tubular body, the inner and outer surfaces of the collet and the inner surface of the collet retainer preferably are circular in cross-section, but may be polygonal in cross-section, subject to the requirements that these surfaces are similarly contoured so that they can match up to enable stable engagement and that the circumferential channel on the outer side of the tubular body is such that the O-ring can enter into a sealing relationship with the inner side of a tube or pipe as the connection with the tube or pipe is effected. In such circumstances, the outer surfaces of the spacer ring, the grab ring and the protection ring would also be correspondingly polygonal in cross-section to enable matching with the collet and collet retainer. 
         [0007]    A significant feature of the present invention is the use of a collet and collet retainer to hold and locate other components relative to the tubular body of the connection fitting. The collet and collet retainer, together with the O-ring, grab ring, spacer ring, protection ring and body, can be easily assembled to form a connection fitting, using basic hand tools. The combination of collet and collet retainer give the connection fitting strength to secure a pipe connection. The protection ring aids easy pipe insertion. The pipe, when inserted, prevents the collet from collapsing inwards and helps strengthen the pipe joint. 
         [0008]    The invention envisages the use of a push connection fitting on a variety of pipes including, but not limited to, copper pipes, polyethylene pipes (PE), polybutylene pipes (PB), polyethylene raised temperature pipes (PE-RT), cross-linked polyethylene pipes (PEX), multi-layer pipes, e.g., cross-linked polyethylene-aluminium-cross-linked polyethylene pipes (PEX-AL-PEX), or chlorinated polyvinyl chloride pipes (CVPC). The connection fitting is designed to seal on the inside of the pipe, using an O-ring, and to grip the pipe on the outside, using a grab ring. The connection fitting can be connect only, or connect/disconnect, and can be a stand-alone fitting, or can be manufactured as part of an end connection for valves. It is to be understood that a plurality of connection fittings can be incorporated in the one device such as in-line joiners, T-joints and Y-joints. A range of different sized connections can be made so as to cover all conventional plumbing/gas pipe sizes. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0009]    An advantage of the invention relates to the making of a pipe connection fitting quickly and economically. Preferably, the design of the connection fitting incorporates a plastic collet and stainless steel collet retainer. While other materials may be used, it is important that they be suitable for the uses to which the collet retainer is put. The preferred materials used in these components allow for simple cost effective manufacturing and assembly. The sealing of the pipe is performed by an O-ring on the tubular body which seals on the inside of the pipe. Sealing on the inside of the pipe allows the body and other components of the connection to be smaller in their diameters, which requires less material. This design allows lower cost material and lower manufacturing cost. The invention allows a more cost effective connection fitting to the market. 
         [0010]    The tubular body can be composed of a thermoplastics material or a thermosetting plastics material. Alternatively, it may be composed of a metal or metal alloy, such as a brass. Preferably it is formed from a thermoplastics material (which is a relatively cheaper material than a metal alloy) by moulding, although a combination of moulding and machining may be used. The tubular body material is preferably a material which does not react with, or leach into, water or other fluids. The outside diameter of the tubular body is less than the inside diameter of the pipe to which connection is to be made so that the tubular body can pass within the open end of the pipe during the process of connection of the pipe to the connection fitting. The outer side of the tubular body (which may be substantially circular or polygonal in cross-section) is provided with a circumferential channel for receiving and retaining an O-ring and with means for engaging a collet, preferably in the form of a circumferential ramp terminating in a channel at or adjacent to the second end of the tubular body. 
         [0011]    Preferably, the collet, which can be composed of a thermoplastics material and which is generally cylindrical (but which may be polygonal in cross-section), has a first plurality of, more preferably four, equally spaced slots opening at the second end of the collet and running through to a plurality of, more preferably four, collet tabs disposed towards the first end of the collet. This plurality of slots allows the collet to expand when it is pushed onto the circumferential ramp of the tubular body. The collet can then ride up the circumferential ramp and an inwardly extending flange on the inside of the collet at the second end of the collet engages and retracts into the circumferential channel at the second end of the tubular body. The collet and tubular body are locked together, at this stage of assembly. Preferably, the collet has a second plurality of, more preferably four, slots equally spaced and opening at the first end of the collet, the second plurality of slots being equally spaced between each collet tab and the first plurality of slots. The second plurality of slots allows the collet to collapse inwards as the collet retainer is attached. The collet tabs have ramps, assisting the collet to compress when the collet retainer passes over the first end of the collet. The plurality of tabs on the collet can subsequently be lined up with a plurality of corresponding slots in the collet retainer. 
         [0012]    The collet retainer, which is generally cylindrical (but which may be polygonal in cross-section), preferably is made of stainless steel for strength. The inside diameter and outside diameter at the outer or first end of the collet retainer is reduced compared to the rest of the collet retainer by means of an inwardly extending shoulder. The collet retainer is provided with a plurality of slots, preferably four, spaced equidistantly around its circumference. The role of this plurality of slots is to engage the plurality of collet tabs and to prevent the collet from expanding and disengaging from the tubular body. 
         [0013]    The O-ring is flexible and can be resiliently distorted from its normal annular configuration for the purpose of tubing a sealing relationship with the pipe. It can be formed from any suitable elastomeric material, such as synthetic rubber, for example, silicones or ethylene propylene diene monomer rubbers, thermoplastic elastomers, polyolefins, polyurethanes, etc. Preferably it is formed from a material that does not react with, or leach into, water. Positioning of the body and O-ring on the inside of the pipe gives the pipe internal support. 
         [0014]    The grab ring can be formed of any suitable material. Stainless steel or spring steel can be used and are preferred materials, although brass alloys and copper may suffice. The grab ring can take the form of a substantially annular ring from which depends a plurality of radially inwardly extending projections or teeth, which in the assembled connection fitting are also directed towards the second end of the collet, i.e., towards the tubular body. These projections or teeth preferably are spaced equally about the grab ring. The grab ring can be split between adjacent projections or teeth. 
         [0015]    The collet retainer locks the collet to the body. The tabs on the collet in turn lock the collet retainer, when the collet tabs click in to the slots on the collet retainer. The grab ring and spacer are inserted into the collet retainer, before it is attached to the collet. When the collet retainer is in the locking position on the collet, the tubular body, collet retainer, grab ring, and spacer ring are all contained as a stable assembly. The collet, collet retainer and grab ring give support to the outside of the fitting, resulting in a strong and secure connection. 
         [0016]    The protection ring at its outer or first end has the same size outside diameter and inside diameter as the pipe to be connected to the connection fitting. The protection ring is designed to centre the collet to the tubular body, protect the O-ring from contamination, compress the O-ring when inserting the pipe and indicate when the pipe is fully inserted. The protection ring is designed with a large chamfer on its inner or second end. This chamfer allows the O-ring to be compressed when inserting the pipe. With the chamfer on the protection ring, there is no need to chamfer the open end of the pipe, which is advantageous. When the pipe is inserted to the fitting, the pipe pushes on the back of the protection ring and when the protection ring comes in contact with the O-ring the O-ring is compressed, allowing the pipe to follow over the O-ring. Preferably, the protection ring is bright in colour, for sighting the protection ring when the pipe is fully inserted. The appearance of this feature in the apertures in the collet and collet retainer indicates full pipe insertion. When the protection ring is inserted at this part of the assembly stage, the collet is unable to collapse and disengage from the collet retainer. When a connection is made, the pipe pushes the protection ring to the end of the fitting. The pipe takes the place of the protection ring to hold the collet open against the collet retainer. On completion of connection, the protection ring becomes the pipe depth indicator. 
         [0017]    The invention allows for easy and quick pipe insertion. When using the correct pipe cutting tool on PEX or PEX-AL-PEX pipe, there is no requirement to chamfer the pipe. When connection is made with this fitting, the protection ring is designed with a chamfer, to provide O-ring compression when pipe is inserted. 
         [0018]    Significant advantageous features of this invention include the operation of the collet, stainless steel collet retainer and the protection ring. The collet and collet retainer allow easy assembly in the manufacturing process and provide the strength and functionality of the connection fitting for pipe insertion. As mentioned previously, the protection ring has a number of functions, the combination of which also provides significant advantages. 
         [0019]    The design of the connection on the invention can be incorporated into, or attached to, other in-line devices, such as valves and other equipment. The end connection can be integral to valves or other equipment. The size of the connection can be selected so that a range of connections cover all conventional and non-conventional plumbing and gas pipe sizes and almost all pipe materials. 
         [0020]    The connection fitting is assembled substantially as follows: the O-ring is located in the O-ring engaging circumferential channel on the tubular body. The collet is then pushed onto the tubular body until it engages the ramp on the tubular body. Under continued pushing the forward portion of the collet rides up the ramp and a forward cross-section of the collet expands preferably by increased separation of forward portions of the collet due to forward opening collet slots. This expansion continues some until the collet reaches the collet engaging channel in the tubular body whereupon the forward cross-section of the collet ceases to expand and an internally directed flange at the forward end of the collet engages with and is located within the collet engaging channel on the tubular body. The spacer ring and grab ring are then placed inside the collet retainer with the spacer ring being located first within the collet retainer and then the grab ring. The collet retainer assembly is then located on the collect and pushed over the collet. This causes the rear or outer end of the collet to compress, preferably via the compression of rear portions of the collet due to slots opening towards the rear or outer end. Tabs on the collet, which are provided with ramps, assist in this procedure by making it easier to push the collet retainer assembly onto the collet. The collet retainer assembly is further pushed onto the collet until the inner end of the collet retainer meets an external flange provided at the inner end of the collet. The collet retainer assembly is rotated around the collet until tabs on the collet click into the collet retainer slots. The rear or outer end of the collet is then allowed to expand and return to its pre-compression state. As a result the collet retainer is locked onto the collet and this also locks the collect onto the tubular body. The protection ring is pushed into and located within the spacer ring within the collet retainer and is further pushed towards the tubular body until it reaches the grab ring in the collet retainer assembly. The connection fitting is now ready for insertion of a tube or pipe. Because the protection ring has the same internal and external diameters as the pipe which the connection fitting is intended, the grab ring can grab the protection ring and hold it in place until insertion of the pipe. When a pipe is inserted the pipe pushes on the outer end of the protection ring and moves it towards the tubular body. The protection ring is chamfered on its inner side and compresses the O-ring as it is pushed further towards the tubular body. This also permits the pipe to ride more easily over the O-ring. There is no need to chamfer the open end of the pipe. As further pushing of the protection ring continues because of further pushing of the pipe into the connection fitting, the protection ring travels further along the tubular body until it meets a ramp on the tubular body and can move no further. At this point the pipe is being inserted fully into the connection fitting. Apertures in the collet retainer and collet allow the protection ring to be seen. As the protection ring preferably is brightly coloured it can be readily identified and this indicates that the pipe has been fully inserted into the connection fitting. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]    In order that the invention may be more clearly understood a preferred embodiment is hereinafter described and shown in the drawings in which: 
           [0022]      FIG. 1  is an exploded view of a preferred embodiment of the invention; 
           [0023]      FIG. 2  is a perspective view of an integral pair of tubular bodies according to a preferred embodiment of the invention; 
           [0024]      FIG. 3  is a view from one end of the body shown in  FIG. 2 ; 
           [0025]      FIG. 4  is a longitudinal cross-section along line A-A of  FIG. 3 ; 
           [0026]      FIG. 5  is a perspective view from the distal end of a collet according to a preferred embodiment of the invention; 
           [0027]      FIG. 6  is a side view of the collet shown in  FIG. 5  with the distal end being on the right; 
           [0028]      FIG. 7  is a view from the distal end of the collet shown in  FIG. 5 ; 
           [0029]      FIG. 8  is a view of the proximal end of the collet shown in  FIG. 5 ; 
           [0030]      FIG. 9  is a longitudinal cross-section along line A-A of  FIG. 8 ; 
           [0031]      FIG. 10  is a perspective view from the proximal end of the collet retainer according to a preferred embodiment of the invention; 
           [0032]      FIG. 11  is a side view of the collect retainer shown in  FIG. 10  the distal end being on the right; 
           [0033]      FIG. 12  is a view from the proximal end of the collet retainer shown in  FIG. 10 ; 
           [0034]      FIG. 13  is a longitudinal cross-section along line A-A of  FIG. 12 ; 
           [0035]      FIG. 14  is a perspective view from the distal end of a spacer ring according to a preferred embodiment of the invention; 
           [0036]      FIG. 15  is a view from the distal end of the spacer ring shown in  FIG. 14 ; 
           [0037]      FIG. 16  is a longitudinal cross-section view along line A-A of  FIG. 15 ; 
           [0038]      FIG. 17  is a perspective view from the proximal side of a grab ring according to a preferred embodiment of the invention; 
           [0039]      FIG. 18  is an end view from the proximal side of the grab ring shown in  FIG. 17 ; 
           [0040]      FIG. 19  is a side sectional view of the grab ring shown in  FIG. 18 ; 
           [0041]      FIG. 20  is a perspective view from the distal end of a protection ring according to a preferred embodiment of the present invention; 
           [0042]      FIG. 21  is a view from the distal end of the protection ring shown in  FIG. 20 ; 
           [0043]      FIG. 22  is a sectional view along line A-A of  FIG. 21 ; 
           [0044]      FIG. 23  is a perspective view of a pair of assembled connection fittings prior to connection of the left hand connection fitting to a pipe or tube. 
           [0045]      FIG. 24  is a longitudinal sectional view through the assembled pair of connection fittings of  FIG. 23 ; 
           [0046]      FIG. 25  is a longitudinal sectional view through the assembled pair of connection fittings during the process of connecting a pipe or tube to the left hand connection fitting; 
           [0047]      FIG. 26  is a longitudinal sectional view through the assembled pair of connection fittings at the completion of connection of a pipe or tube to the left hand connection fitting. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
       [0048]    In the drawings the numeral  10  designates generally a pair of connection fittings according to a preferred embodiment of the invention, one of the connection fittings  10   a  being shown in the assembled form and the other  10   b  being shown in an exploded view. Here, the connection fittings  10   a  and  10   b  are integrated to form an in-line joining means. In the following description, comments will be limited to that part of the pair of connection fittings shown in the exploded view in  FIG. 1 , i.e.,  10   b.    
         [0049]    In the exploded view the configurational relationship between the components of the preferred embodiment connection fitting can be seen. The terms “proximal”, and “distal”, in the above identification of the drawings and in the following description is used to indicate those ends of the components which are, respectively, closer to the mid-point of the pair of connection fittings  10 , and further from the mid-point of the pair of connection fittings  10 . 
         [0050]    Tubular body  12 , forming part of connection fitting  10   b , is composed of a plastics material and has a uniform bore  26 , the distal end  28  of which is chamfered  30 . Adjacent the mid-point  32  of the integral pair of tubular bodies, i.e., at the proximal end of tubular body  12 , there is provided, on the outer side  38  of tubular body  12 , a collet-engaging channel  34  on the distal side of which is disposed a ramp  36 . Both collet-engaging channel and ramp  36  circumscribe tubular body  12 . Disposed on the outer side  38  and toward the distal end of tubular body  12  is an O-ring-engaging channel  40 , which circumscribes the outer side  38 . 
         [0051]    The O-ring  14  is a typical O-ring, dimensioned to be engaged and restrained from movement by the O-ring-engaging channel  40 . The distal end of the outer side  38  of the tubular body  12  is also chamfered  42 . 
         [0052]    The collet  16  is comprised of spring steel. It is generally cylindrical and is provided with four slots  44  opening at the proximal end and an additional four slots  45  opening at the distal end, and four tabs  46  evenly spaced around the circumference. At the proximal end is provided an external flange  48  and an internally directed flange  49 , both intersected by the proximally directed slots  44 . The flange  48  is chamfered  50  on its proximal side. The internal wall  52  of the collet is chamfered  54  at its distal end  56 . 
         [0053]    The collet retainer  18  is also generally cylindrical and is composed of stainless steel. The distal end  58  is chamfered  60  into an opening  62  with a slightly narrower diameter than the bore  64  of the main part of the collet retainer  18 . Four slots  66  are disposed circumferentially at even intervals around the body of the retainer  18 . 
         [0054]    Grab ring  20  is formed from spring steel and takes the form of a substantially angular ring  68  from which depends a plurality of radially inwardly extending teeth  70 . The teeth  70  are spaced equal distantly around the inner edge of the ring  68 . The grab ring  20  is initially formed as a flat blank. Then the teeth  70  are pushed out of the plane of the ring  68  so that they project in a proximal direction at an angle to the plane of the ring  68  with the innermost edges  72  of the teeth  70  being sharp to aid in engagement with the pipe or tube following insertion of the same into the connection fitting and thereby restrain the pipe or tube from being subsequently withdrawn from the connection fitting. 
         [0055]    The spacer ring  22  is formed from a plastics material. It is generally cylindrical with a ridge  74  being formed on the outer side  76  towards the proximal opening  78  and chamfers  80 ,  82  on the outer side  76  and inner side  84  at the distal opening  86 . The diameter of the spacer ring  22  is otherwise constant. 
         [0056]    The protection ring  24  is also generally cylindrical, although its internal diameter at the proximal end  88  is greater than at the distal end  90 , there being a radially inwardly directed annular ramp  92  extending from a point adjacent the distal end  90  to a point adjacent the proximal end  88  of the protection ring  24 , thereby defining two inner rings of differing diameters joined by a smooth ramp section. The protection ring is brightly coloured so as to provide a visual indication of the completion of the connection of a pipe to the connection fitting. 
         [0057]    The assembly procedure starts with the locating of the O-ring  14  in the O-ring-engaging channel  40  on the tubular body  12 . The collet  16  is then pushed on to the tubular body  12  until it engages ramp  36 . As pushing continues the collet  16  rides up ramp  36  and the collet  16  expends via the four proximally-opening collet slots  44  until collet  16  reaches the collet-engaging channel  34  on the tubular body  12  whereupon the collet  16  ceases to expand and the internally directed flange  49  at the proximal end of collet  16  engages with, and is located in, the collet-engaging channel  34 . 
         [0058]    Spacer ring  22  and grab ring  20  are placed inside collet retainer  18 , grab ring  20  being located proximally in relation to spacer ring  22 . The resulting collet retainer assembly is then located onto the collet  16  and the bore  64  of the collet retainer  18  encompasses the outer side of collet  16 . As a small amount of force is applied to push the collet retainer  18  onto the collet  16  the collet  16  compresses via the four distally-opening slots  45 . Tabs  46  on the collect  16  are provided with ramps  47  (as can be seen in  FIGS. 5, 6 and 9 ) which assist in this procedure by making it easier to push the collet retainer assembly onto collet  16 . The collet retainer assembly is pushed onto collet  16  until the proximal end of the collet retainer  18  meets external flange  48  provided at the proximal end of collet  16 . Keeping the collet  16  stationary, the collet retainer assembly is rotated around the collet  16  until the four collet tabs  46  click into the four collet retainer slots  66 . Collet  16  is then allowed to expand and return to its pre-compression state. The collet retainer  18  is now locked onto collet  16  and has also locked collet  16  onto the tubular body  12 . Spacer ring  22  and grab ring  20  are now secured inside the collet retainer  18 . 
         [0059]    The protection ring  24  is pushed into and located within the spacer ring  22  and is pushed proximally with respect to the tubular body  12  until it reaches the grab ring  20  in the collet retainer assembly. The protection ring  24  has the same internal and external diameters as the pipe for which the connection fitting  10   b  is intended. This allows the grab ring  20  to grab the protection ring  24  and hold it in place until insertion of the pipe. The protection ring  24  also locates onto the tubular body  12  which assists in centering the collet  16 , gab ring  20 , spacer ring  22  and collet retainer  18  onto the tubular body  12 . Further, the protection ring  24 , by locating on tubular body  12  and being inside the spacer ring  22 , protects the O-ring  14  from contamination by foreign matter prior to pipe insertion.  FIG. 24  shows in cross-section an assembled pair of connection fittings  10  prior to pipe insertion. 
         [0060]    When a pipe is inserted the pipe  100  pushes on the distal end of the protection ring  24 . As the protection ring  24  is moved proximally within the connection fitting it compresses O-ring  14  and permits the pipe  100  to ride more easily over the O-ring  14 , without the need to chamfer the open end  102  of the pipe  100 . As proximal movement of the protection ring  24  continues, due to further pushing of the pipe  100  into the connection fitting, the protection ring  24  continues to travel proximally until it meets the ramp  36  and can move no further. At this point the pipe has been inserted fully into the connection fitting. With the protection ring  24  being brightly coloured and resting against ramp  36  it becomes visible through the proximally opening slots  44  in the collet  16 . This indicates that the pipe has been fully inserted into the connection fitting. 
         [0061]    It is to be understood that the invention may embrace many further modifications as would be readily apparent to persons skilled in the art and which would be deemed to reside within the broad scope and ambit of the invention. The preferred embodiment described above is by way of example only and is not to be considered as limiting. 
         [0062]    Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 
         [0063]    The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general knowledge.