Abstract:
The present invention relates to sliding supports and particularly sliding supports having two elongate members of channel section and an intermediate member positioned between the elongate members. The invention provides a sliding support with improved manufacturability and load bearing capability by providing an intermediate member of alternative cross-section.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of International Patent Application No. PCT/GB2009/001476 filed Jun. 12, 2009, which claims priority to Great Britain Patent Application No. GB0810896.1, filed Jun. 13, 2008. Each of these priority applications is hereby expressly incorporated by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO A “SEQUENCE LISTING” 
       [0003]    Not applicable. 
       FIELD OF THE INVENTION 
       [0004]    The invention relates to sliding supports. 
       BACKGROUND OF THE INVENTION 
     Description of Related Art 
       [0005]    It is known to provide sliding supports for use in furniture or domestic appliances, such as ovens and dishwashers. Such sliding supports having two (or more) elongate members, typically of shallow channel section, which slide one within the other, one of the members being secured to a slidable drawer or rack, and the other to a frame in which the drawer or rack is supported. Sliding engagement between the members is typically provided by ball bearings retained by a retaining member located between the two elongate members. 
         [0006]    It is also known to provide sliding supports having two elongate channel section members offset relative to one another, and an intermediate member positioned between the two elongate members. Sliding engagement between the members is provided by ball bearings positioned between the elongate members and the intermediate member and retained by retaining members located within the channel section elongate members. Such a sliding support as manufactured by the present applicant, Accuride International Limited, is shown in  FIG. 1 . The arrangement of  FIG. 1  provides a unit which is compact for its strength. However, it is desirable to provide a unit with an increased load bearing capability. 
         [0007]    Accordingly, there is a need for an improved compact sliding support which offers increased load bearing capability. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    According to the invention, there is provided a sliding support comprising: 
         [0009]    a first elongate slide member of channel section defining a first web and first and second flanges, 
         [0010]    a second elongate slide member of channel section defining a second web and third and fourth flanges, 
         [0011]    an intermediate member positioned between the first and second slide members, 
         [0012]    first locating means positioned between the first slide member and the intermediate member to locate and align the first slide member and the intermediate member for sliding without contact therebetween, and 
         [0013]    second locating means positioned between the second slide member and the intermediate member to locate and align the second slide member and the intermediate member for sliding without contact therebetween, wherein 
         [0014]    the first and second flanges are offset relative to the third and fourth flanges in a direction parallel to the first and second webs, and 
         [0015]    the intermediate member has a cross-section comprising a third channel section connected to a fourth channel section by a connecting member arranged at an angle to the first and second webs. 
         [0016]    The sliding support of the present invention is a compact unit which, consequently, has a reduced material requirement and is thus a cost-effective design. 
         [0017]    By incorporating a connecting member which is arranged at an angle to the first and second webs, some flexing is allowed in the intermediate member. The present inventors found that such flexing increases the load bearing capacity of the support over similarly sized prior art supports. The improved intermediate member also adds stability to the support. This design of member also makes manufacture easier and more consistent than for known prior art. 
         [0018]    The sliding support is for supporting any element or body required to be linearly movably mounted relative to another body. 
         [0019]    The offsetting of the first and second slide members relative to one another benefits the mounting of the sliding bodies relative to one another. 
         [0020]    The cross-section of the intermediate member may be unhanded. Consequently, left-handed and right-handed sliding supports can be manufactured using the same intermediate member and slide members. Consequently, the cost-efficiency of manufacturing the sliding supports is optimised. 
         [0021]    The third channel section may define a third web and fifth and sixth flanges, and the fourth channel section may define a fourth web and seventh and eighth flanges, and the fifth flange may be connected to the seventh flange by the connecting member. 
         [0022]    The connecting member may comprise a fifth web which connects the fifth and seventh flanges together at their open ends. 
         [0023]    The angle between the connecting member and the first and second webs may be in the range of 70 to 80 degrees. Alternatively, the angle between the connecting member and the first and second webs may be in the range of 60 to 85 degrees. Alternatively, the angle between the connecting member and the first and second webs may be in the range of 30 to 85 degrees. The angle may take any value provided that the connecting member is not parallel to the first and second webs. 
         [0024]    The first and second locating means may each comprise a multiplicity of ball bearings and a retainer for retaining the ball bearings in two parallel rows, one row on each side of each of the first and second slide members, between the first and second slide members and the intermediate member, to locate slidingly the intermediate member within the first and second slide members. 
         [0025]    In particular, a first row of ball bearings may be positioned between the first and sixth flanges, a second row of ball bearings may be positioned between the second and seventh flanges, a third row of ball bearings may be positioned between the third and fifth flanges, and a fourth row of ball bearings may be positioned between the fourth and eighth flanges. 
         [0026]    The cross-sectional profile of each of the first to eighth flanges may be shaped to provide half of a ball engaging channel such that the rows of ball bearings are retained between the respective first and second slide members and the intermediate member in a plurality of ball channels. Preferably, the ball bearings are retained in four separate ball channels. 
         [0027]    The ball retainer is preferably formed of polymeric material (for example material sold under the registered trade mark Nylon 66). 
         [0028]    The shape of the intermediate member is a positive influence on the strength of the sliding support in operation. The amount of distortion (wind out) of the balltracks when the sliding support is tested to destruction is significantly less than expected: the sliding supports are able to withstand more weight than anticipated. Moreover, on cycle testing the amount of permanent deformation is less than expected. 
         [0029]    In an alternative configuration, the first and second locating means may each comprise a plastics strip, preferably of self-lubricating plastics material, arranged between the respective slide member and the intermediate member, to locate slidingly the intermediate member within the first and second slide members. 
         [0030]    The first and second slide members and the intermediate member may be made of steel, such as mild or stainless steel (or other suitable material). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    By way of example, an embodiment of a sliding support according to the invention will now be described with reference to the accompanying drawings, in which: 
           [0032]      FIG. 1  is a sectional view of a sliding support according to the prior art; and 
           [0033]      FIG. 2  is a sectional view of a sliding support according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    As mentioned above,  FIG. 1  shows a sectional view of a prior art sliding support generally indicated at  101 . 
         [0035]    The prior art sliding support  101  includes a first elongate slide member  10  of channel section defining a first web  12  and first and second flanges  14 ,  16 . The support  100  also includes a second elongate slide member  20  of channel section defining a second web  22  and third and fourth flanges  24 ,  26 . An intermediate member  30  is positioned between the first and second slide members  10 ,  20 . Two parallel rows of ball bearings  40  are positioned between the first slide member  10  and the intermediate member  30  to locate and align the first slide member  10  and the intermediate member  30  for sliding without contact therebetween. Two further parallel rows of ball bearings  42  are positioned between the second slide member  20  and the intermediate member  30  to locate and align the second slide member  20  and the intermediate member  30  for sliding without contact therebetween. The first and second flanges  14 ,  16  are offset relative to the third and fourth flanges  24 ,  26  in a direction parallel to the first and second webs  12 ,  22 . The intermediate member  30  has a section comprising a third channel section  32  connected to a fourth channel section  34  by a connecting member  36  arranged parallel to the first and second webs  12 ,  22 . 
         [0036]    According to an embodiment of the present invention as shown in  FIG. 2 , there is provided a sliding support  200  comprising a first elongate slide member  110  of channel section defining a first web  112  and first and second flanges  114 ,  116 . The sliding support  200  also includes a second elongate slide member  120  of channel section defining a second web  122  and third and fourth flanges  124 ,  126 . An intermediate member  130  is positioned between the first and second slide members  110 ,  120 . Two parallel rows of ball bearings  140  are positioned between the first slide member  110  and the intermediate member  130  to locate and align the first slide member  110  and the intermediate member  130  for sliding without contact therebetween. Two further parallel rows of ball bearings  142  are positioned between the second slide member  120  and the intermediate member  130  to locate and align the second slide member  120  and the intermediate member  130  for sliding without contact therebetween. The first and second flanges  114 ,  116  are offset relative to the third and fourth flanges  124 ,  126  in a direction parallel to the first and second webs  112 ,  122 . The intermediate member  130  has a cross-section comprising a third channel section  132  connected to a fourth channel section  134  by a connecting member  136  arranged at an angle to the first and second webs  112 ,  122 . 
         [0037]    The third channel section  132  is defined by a third web  151  and fifth and sixth flanges  152 ,  153  and the fourth channel  134  section is defined by a fourth web  154  and seventh and eighth flanges  155 ,  156 . The fifth flange  152  is connected to the seventh flange  155  by the connecting member  136 . 
         [0038]    The angle between the connecting member  136  and the first and second webs  112 ,  122  is in the range of 70 to 80 degrees. However, the angle may take any value provided that the connecting member  136  is not parallel to the first and second webs  112 ,  122 . 
         [0039]    Four rows of ball bearings are retained in parallel rows by two retainers  143 , one row on each side of each of the first and second slide members  110 ,  120 , between the first and second slide members  110 ,  120  and the intermediate member  130 , to locate slidingly the intermediate member  130  within the first and second slide members  110 ,  120 . 
         [0040]    The retainers  143  each have a base, extending parallel to the webs of the first and second slide members  110 ,  120 , and side webs which both carry a series of holes of a size to be engaged by and retain the ball bearings  140 ,  141 . 
         [0041]    In particular, a first row of ball bearings  140  is positioned between the first and sixth flanges  114 ,  153 , a second row of ball bearings  140  is positioned between the second and seventh flanges  116 ,  155 , a third row of ball bearings  141  is positioned between the third and fifth flanges  124 ,  152 , and a fourth row of ball bearings  141  is positioned between the fourth and eighth flanges  126 ,  156 . 
         [0042]    The cross-sectional profile of each of the first to eighth flanges  114 ,  116 ,  124 ,  126 ,  152 ,  153 ,  154 ,  155  is curved to provide half of a ball engaging channel such that the rows of ball bearings  140 ,  141  are retained between the respective first and second slide members  110 ,  120  and the intermediate member  130  in a plurality of ball channels. 
         [0043]    In use, the first slide member  110  is fixedly mounted to a first body (not shown). The second slide member  120  is fixedly mounted to a second body (not shown) in relation to which the first body is to be slidable linearly. 
         [0044]    It will be appreciated that the embodiment described in detail has been described by way of example only, and that alterations or modifications may be made within the scope of the invention as defined in the appended claims.