Abstract:
Disclosed is a chain lubricating apparatus comprising a sprocket and a lubricant delivery means wherein, in use, the sprocket is free to rotate about an axis and comprises teeth that engage with the chain. The lubricant delivery means is configured such that lubricant is delivered to a specific part of the chain when the sprocket is in a particular angular configuration with respect to the axis.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a chain lubricating apparatus and method. 
       BACKGROUND OF THE INVENTION 
       [0002]    Chains are used throughout industry and in many mechanical devices. An inherent problem with chains arises due to the fact that chains contain moving parts and there is friction between chain sections. To reduce the damage caused by friction and to prolong the life of the chain, lubricant can be added to the chain. Established chain lubricating techniques involve running the chain through a lubricant bath or brushing lubricant onto the chain. This leads to further problems; the application can be messy, there can be contamination of the lubricant source, expensive lubricant may be used to excess and wasted, and these techniques do not target particular sections of the chain so the lubrication process is inefficient. 
         [0003]    Embodiments of the present invention aim to address problems associated with chain lubrication, whether mentioned herein or not. 
       SUMMARY OF THE INVENTION 
       [0004]    In a first aspect, the present invention provides a chain lubricating apparatus comprising a sprocket and a lubricant delivery means; wherein in use the sprocket is free to rotate about an axis and comprises teeth that engage with the chain; the lubricant delivery means is configured such that lubricant is delivered to a specific part of the chain when the sprocket is in a particular angular configuration with respect to the axis. 
         [0005]    Suitably, the lubricant delivery means is configured whereby lubricant is delivered to the chain from the underside of the chain. Suitably, lubricant is delivered to the chain at multiple defined locations. 
         [0006]    Suitably, the chain lubricating apparatus is configured whereby the lubricant is delivered to a specific part of the chain for a limited period of time. Suitably, the period of time is determined by an angular arc such that as the sprocket is rotated through the arc, the lubricant is delivered. 
         [0007]    Suitably, the chain lubricating apparatus is configured whereby lubricant is delivered to a specific part of the chain when the sprocket is in one of a plurality of angular configurations. 
         [0008]    Suitably, the chain lubricating apparatus further comprises a lubricant source. Suitably, the lubricant source is pressurised. 
         [0009]    Suitably, the chain lubricating apparatus further comprises a lubricant return means which enables excess lubricant not delivered by the lubricant delivery means to the chain to return to the lubricant source. 
         [0010]    Suitably, the lubricant source and the chain lubricating apparatus form a closed system for the lubricant. 
         [0011]    Suitably, the sprocket comprises a sprocket lubricant channel. Suitably, the sprocket lubricant channel leads from an inner region of the sprocket to an outer region of the sprocket. Suitably, the sprocket lubricant channel terminates at a position in line with the particular part of the chain to be lubricated. Suitably, the sprocket lubricant channel terminates at a plurality of positions in line with the particular parts of the chain to be lubricated. Suitably, the sprocket comprises a plurality of sprocket lubricant channels. 
         [0012]    In a different arrangement, the sprocket has a first surface and a second surface, and a disc is arranged such that its inner surface lies flush against the sprocket first surface; wherein the disc comprises a disc lubricant channel. Suitably, the disc lubricant channel leads from an inner region of the disc to an outer region of the disc. Suitably, the disc lubricant channel terminates at a position in line with the particular part of the chain to be lubricated. Suitably, the disc lubricant channel terminates at a plurality of positions in line with the particular parts of the chain to be lubricated. Suitably, the disc comprises a plurality of disc lubricant channels. 
         [0013]    Suitably, the sprocket comprises an outer sprocket and an inner sprocket section where the inner sprocket section comprises a sprocket lubricant channel and the disc comprises a disc lubricating channel and the outer sprocket and disc are free to rotate about the axis relative to the inner sprocket section, whereby the inner sprocket section and the disc are configured such that when the sprocket lubricant channel and the disc lubricant channel are aligned, lubricant passes through the sprocket lubricant channel into the disc lubricant channel and is delivered to the chain. 
         [0014]    Suitably, the outer sprocket and the disc are connected together. 
         [0015]    Suitably, the sprocket lubricant channel terminates at the position where the disc lubricant channel begins. Suitably, the sprocket lubricant channel terminates at a position towards the outer region of the sprocket. 
         [0016]    Suitably, a first disc is arranged such that its inner surface lies flush against the sprocket first surface and a second disc is arranged such that its inner surface lies flush against the sprocket second surface. 
         [0017]    Suitably, the sprocket and the disc are configured whereby lubricant can escape from the sprocket lubricant channel or from the disc lubricant channel and form a thin layer of lubricant between the sprocket and the disc. 
         [0018]    Suitably, the chain lubricating apparatus is configured whereby the movement of the chain causes the rotation of the sprocket about the axis. 
         [0019]    In a different arrangement, the sprocket is mounted on a drive shaft which rotates the sprocket as the drive shaft is rotated. 
         [0020]    Suitably, the lubricant delivery means delivers the lubricant to the chain under the force of gravity. 
         [0021]    Suitably, the lubricant delivery means delivers the lubricant to the chain under the centrifugal force as the sprocket is rotated. 
         [0022]    Suitably, the lubricant delivery means delivers the lubricant to the chain under pressure applied to the lubricant. 
         [0023]    In a second aspect, the present invention provides a chain lubricating method comprising the steps: rotating a sprocket about an axis; engaging the sprocket with a chain; and delivering lubricant to a specific part of the chain when the sprocket is in a particular angular configuration with respect to the axis. 
         [0024]    Suitably, lubricant is delivered to the underside of the chain. Suitably, lubricant is delivered to multiple defined locations. 
         [0025]    Suitably, lubricant is delivered to a specific part of the chain for a limited period of time. Suitably, the period of time is determined by an angular arc such that as the sprocket is rotated through the arc, the lubricant is delivered. 
         [0026]    Suitably, lubricant is delivered to a specific part of the chain when the sprocket is in one of a plurality of angular configurations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: 
           [0028]      FIG. 1  shows a perspective view of one embodiment of the disclosed chain lubricating apparatus showing the sprocket and disc assembly; 
           [0029]      FIG. 2  shows a perspective view of the sprocket of  FIG. 1 ; 
           [0030]      FIG. 3  shows a perspective view of the disc of  FIG. 1 ; and 
           [0031]      FIG. 4  shows an exploded view of an embodiment of the disclosed chain lubricating apparatus. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0032]    Referring to  FIG. 1  there is shown a chain lubricating apparatus according to an embodiment of the disclosure. The chain lubricating apparatus comprises a sprocket  10  having an outer sprocket  11 , sprocket teeth  12  and an inner sprocket section  13  (shown in  FIG. 2 ), and positioned on a shaft  14 . A chain  16  is shown interlocked with the sprocket teeth  12  and comprises chain rollers  18 , chain pins  20 , chain inner plates  22  and chain outer plates  24 . A disc  26  has disc lubricant outlets  28 ,  30  and is positioned on the shaft  14  next to the sprocket  10 . 
         [0033]    As discussed in more detail below, the chain  16  is positioned on the outer sprocket  11  such that the disc lubricant outlet  28  is aligned with the junction between the chain outer plate  24  and the chain inner plate  22 , and the disc lubricant outlet  30  is aligned with the junction between the chain roller  18  and the chain inner plate  22 . The points of greatest friction within the chain are where the chain outer plate  24  and chain inner plate  22  overlap, and where the chain roller  18  is in contact with the chain inner plate  22 . Lubricant is delivered through the disc lubricant outlets  28 ,  30  specifically to these points of greatest friction on the underside of the chain  16 . This targeted delivery of lubricant ensures that the lubricant is delivered to the chain at the required location of greatest friction. This gives a more efficient delivery means with less mess and less waste of lubricant. 
         [0034]    Whilst  FIG. 1  shows a first disc  26  on a first side of the sprocket  10 , it will be appreciated that a second disc of similar construction to the first disc can also be placed on the opposite side of the sprocket  10 . This second disc acts in the same way to deliver lubricant through disc lubricant outlets and target the points of greatest friction on the other side of the chain. 
         [0035]    Referring now to  FIGS. 2 and 3  and the chain lubricating apparatus described above in relation to  FIG. 1 .  FIG. 2  shows the sprocket  10  having outer sprocket  11  and inner sprocket section  13  positioned on the shaft  14 . The shaft comprises a shaft lubricant inlet  32  which connects to a sprocket lubricant channel  34  contained within the inner sprocket section  13 . The sprocket lubricant channel  34  leads to a sprocket lubricant aperture  36 . The inner sprocket section  13  also comprises a lubricant return channel  38  which is an open channel in the surface of the inner sprocket section  13 . 
         [0036]      FIG. 3  shows the disc  26  comprising disc bearings  40 , a disc lubricant inlet  42  which connects to a disc lubricant channel  44  and ends at the disc lubricant outlets  28 ,  30 . 
         [0037]    Both the sprocket  10  and the disc  26  are positioned on the shaft  14 . The outer sprocket section  11  is connected to the disc  26 . The inner sprocket section  13  is connected to the shaft  14 . The disc bearings  40  allow the disc  26  and the outer sprocket  11  to rotate freely relative to the shaft  14  and the inner sprocket section  13 . The disc  26  and the sprocket  10  are arranged such that they fit closely together with no substantial gaps therebetween. The outer sprocket  11  and disc  26  are rotated together. The inner sprocket section  13  is fixed in place and therefore there is relative rotation between the inner sprocket section  13  and the disc  26  and outer sprocket  11  combination. In operation, lubricant passes through the shaft lubricant inlet  32  into the sprocket lubricant channel  34 . The disc  26  is rotated relative to the inner sprocket section  13  and at one or more defined points in the rotation cycle the sprocket lubricant aperture  36  will overlap with the disc lubricant inlet  42 . During the period of overlap, lubricant can pass through the sprocket lubricant channel  34  into the disc lubricant channel  44  and onto the chain through the disc lubricant outlets  28 ,  30 . 
         [0038]    In this way, lubricant is only free to pass through the disc lubricant outlets  28 ,  30  when the disc  26  and the sprocket  10  are in a particular angular configuration. The frequency of the lubricant delivery is determined by the relative speed of rotation of the disc  26  with respect to the inner sprocket section  13 . The duration of each lubricant delivery is determined by the time of overlap between the sprocket lubricant aperture  36  and the disc lubricant inlet  42 . It will be appreciated that the size of the sprocket lubricant aperture  36  and the disc lubricant inlet  42  can vary to increase or decrease the duration of lubricant delivery. Also, the shape of the sprocket lubricant aperture  36  and/or the disc lubricant inlet  42  could be tapered along the direction of overlap. This would act to vary the amount of lubricant delivered so as to provide a slow delivery of lubricant on initial overlap and a quick delivery of lubricant on further overlap. Also, multiple disc lubricant inlets  42 , disc lubricant channels  44  and disc lubricant outlets  28 ,  30  could be provided so as to provide multiple lubricant delivery means to multiple locations on the chain  16 . 
         [0039]    The lubricant is delivered from a lubricant source which is under pressure. When the disc  26  and the inner sprocket section  13  are in an angular configuration such that the sprocket lubricant aperture  36  is not overlapping the disc lubricant inlet  42 , lubricant will be in the sprocket lubricant channel  34  under pressure. In this state, a small amount of lubricant will pass through the sprocket lubricant aperture  36  into the space between the inner sprocket section  13  and the disc  26 . This will provide a thin layer of lubricant between the disc  26  and the inner sprocket section  13  which will facilitate their relative rotation and reduce friction between the two. 
         [0040]    Also, when the sprocket lubricant aperture  36  and disc lubricant inlet  42  are not overlapping, lubricant will remain in the disc lubricant channel  44 . A lubricant return channel  38  is therefore provided such that when the disc lubricant inlet  42  overlaps the lubricant return channel  38 , lubricant can pass from the disc lubricant channel  44  into the lubricant return channel  34  and back to a lubricant return reservoir. 
         [0041]    Referring now to  FIG. 4 , an exploded view of the chain lubricating apparatus shows a sprocket  10  comprising an outer sprocket  11  and an inner sprocket section  13  having discs  26  on each side of the sprocket  10  so as to deliver lubricant to both sides of the chain  26  by the means already described above. 
         [0042]    It will be appreciated that modifications may be made to the example embodiment described herein without detracting from the present invention. The sprocket and shaft may rotate freely or the shaft may be a drive shaft and drive the sprocket. Alternatively the shaft and sprocket may be held in place and the disc may rotate to provide relative rotation between the disc and the sprocket. The lubricant may be supplied under pressure and/or under the force of gravity and/or under the force of a centrifugal force. The lubricant source and the lubricant return reservoir may be different or the same. Furthermore, if they are the same, the system may comprise a closed system. 
         [0043]    Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. 
         [0044]    All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. 
         [0045]    Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
         [0046]    The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.