Abstract:
Spring tensioner devices are provided for biasing scraper blades toward a conveyor belt. The spring tensioner devices generally are constructed to be easily reconfigurable between a push-up and pull-up configuration while minimizing their space requirements.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of the filing date of U.S. Provisional Application 61/196,483 filed Oct. 17, 2008, which is hereby incorporated in its entirety herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a belt cleaning apparatus and, more particularly, to a reconfigurable spring tensioner for a conveyor belt cleaning apparatus and method for reconfiguring such an apparatus. 
       BACKGROUND OF THE INVENTION 
       [0003]    Conveyor belts are used in a variety of industries (e.g., coal, aggregate, packaging) to transport goods and materials. Based on the material transported and the ambient conditions surrounding the conveyor belt, material can become undesirably affixed to the belt. The material can be removed from the belt in a number of ways, including, but not limited to the use of a belt cleaning apparatus utilizing spring tensioners. 
         [0004]    A belt cleaning apparatus cleans the belt in place, during operation, via a scraping action thereagainst. A belt cleaning apparatus typically will include a cleaner blade or blades having a scraper or tip end that is biased into engagement with the belt surface, usually on the return run of the belt (secondary belt cleaners) or at the head pulley (primary belt cleaners). In either type of belt cleaner, the scraper blade will typically be mounted to an elongate pole extending below and across the belt to the frame structure of the conveyor system on either side of the belt for being operatively supported thereby. In this regard, the opposite ends of the pole can be mounted to biasing units secured to frame structures for providing an upward bias force for urging the scraper blade into engagement with the belt surface. 
         [0005]    Exemplary prior art spring tensioner units are disclosed in U.S. Pat. Nos. 6,874,616 to DeVries and 7,093,706 to DeVries, which are incorporated as if reproduced in their entirety herein. These units provide both a rotary bias force and an upward, linear bias force to the pole via a Rosta-type torsion biasing mechanism and a spring loaded housing assembly of the torsion biasing mechanism. Depending on space requirements, the tensioner units are mounted to the conveyor frame structure with either a pull-up or push-up configuration. In the pull-up configuration the coil spring providing the linear bias force is arranged on the fixed mounting frame flange above the housing assembly mounted for translation along the mounting frame member to exert an upward bias force that draws or pulls the housing assembly upward. In the push-up configuration the tensioner unit is rotated 180 degrees about the longitudinal axis of the mounting pole. In this configuration, the coil spring is arranged below the housing assembly and between the fixed mounting frame flange and the translatable housing assembly to exert an upward bias force that pushes the housing assembly upward. However, switching from one configuration to another requires significant disassembly and re-assembly of the unit. 
         [0006]    More particularly, the coil spring has to be reoriented relative to the mounting frame flange of the unit against which the spring abuts. To do this, the entire housing assembly is detached from the guide bearings on the mounting bracket. This allows the position of the spring to be changed from one side of the bracket flange to the other with the housing assembly then reconnected to the linear guides on the bracket once the spring is properly positioned. The disassembly required for reconfiguring the tensioner units is undesirable from a time and labor standpoint. 
         [0007]    Accordingly, there is a need for a spring tensioner that can be more easily reconfigured between pull-up and push-up configurations. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with one aspect of the invention, a tensioner unit for a belt scraper is provided that is easily reconfigurable between push-up and pull-up configurations thereof. In this regard, changing the configuration of the present tensioner unit does not require significant disassembly of the tensioner unit for reconfiguration thereof. 
         [0009]    For instance, instead of having to disconnect a housing assembly of the tensioning unit from its mounting frame member to which it is slideably mounted, the mounting frame member includes a detachable portion that is easily removed from the mounting frame member allowing the housing assembly to stay connected thereto for reconfiguration of the tensioner unit. 
         [0010]    In a preferred form, the tensioning units have a spring member that provides a linear bias force upwardly to the housing assembly. The detachable portion of the Mounting frame member is a spring mount against which one end of the spring is seated. Thus, removing the spring mount allows the position of the spring relative to the housing assembly and mounting frame member to be easily changed while keeping the housing assembly connected to the slide bearings on the mounting frame member. 
         [0011]    In one form, the housing assembly receives an end portion of an elongate member secured therein. The elongate member extends under and across the conveyor with a belt scraper mounted to the elongate member. A rod is fixed to the housing assembly and extends upwardly therefrom in the pull-up configuration, and downwardly therefrom in the push-up configuration with the spring being a coil spring seated with its coils extending about the rod. In this manner, the spring is operable to bias the belt scraper toward the conveyor belt in scraping engagement therewith. 
         [0012]    In another aspect, a method of reconfiguring a spring tensioner unit between push-up and pull-up configurations is provided. The method includes removing either a spring from the rod or a spring support member from a wall of the unit, depending on the configuration of the unit. After both of these steps, the unit is reoriented and the spring is able to be mounted back on the rod without requiring that it be removed from the unit such as with prior spring tensioners that required the rod along with the housing assembly to which it is attached to be removed from the wall of the mounting frame of the tensioner unit for this purpose. Then, both the spring is replaced on the rod and the spring support is mounted onto the wall of the unit, the order of which depending on the configuration of the unit. 
         [0013]    More specifically, in the push-up configuration, the spring is positioned between the housing assembly and the mounting plate detachable portion. In the pull-up configuration, the mounting plate detachable portion is positioned between the spring and the housing assembly, the spring positively secured on the rod, such as with a nut. As such, the tensioning units can be reconfigured between the push-up and pull-up configurations by removing and reconfiguring the spring, securing member and the mounting plate detachable portion without having to manipulate the housing assembly or the rod extending therefrom relative to the mounting plate. 
         [0014]    Additionally, the configuration of the prior art spring tensioner, in particular the overall size and the different mounting footprints depending on the configuration utilized, presented obstacles in maintaining and installing a spring tensioner in applications without ample space. While possible to minimize the space requirements by minimizing the potential travel of the housing mechanism or by reducing the spring size, operating the spring tensioner in such a manner limits the operational effectiveness of the spring tensioner. 
         [0015]    In accordance with another aspect of the invention, a spring tensioner is provided having a compact design. The spring tensioner includes a housing assembly for supporting an elongate member extending below the belt. The housing assembly is attached to a vertical wall portion of a mounting plate by a linear guide device which permits the housing assembly to shift in a vertical direction along the plate. The spring tensioner further includes a rod extending from the housing assembly about which a biasing mechanism of the spring tensioner is positioned. The rod extends through a horizontal ledge extending from the vertical wall portion of the mounting plate. 
         [0016]    In a preferred form, the horizontal ledge of the mounting plate includes a horizontal seat portion against which the biasing mechanism abuts. Extending from the horizontal set portion is a pair of vertical walls between which the biasing mechanism can be received. In one form, the horizontal ledge includes an opening aligned with the rod and a mounting member extending across the opening including the horizontal seat portion and the vertical walls. 
         [0017]    By including the vertical walls of the mounting member the overall size of the spring tensioner unit is decreased. First, the height of the mounting frame can be decreased by an amount equal to the size of the vertical walls as will be discussed further below. Additionally, the rod can also be reduced in length by an amount up to two times the size of the vertical walls as will be discussed further below. Therefore, the presence of the vertical walls of the mounting member can reduce the overall height of the spring tensioner unit by approximately at least twice the height of the step. 
         [0018]    In another embodiment of the invention, a spring tensioner unit is provided having a reduced size. In particular, the housing assembly of the spring tensioner which receives the pole extending below and across the belt is configured to have a minimized size. The housing assembly includes an inner housing for receiving the pole extending across the belt. An outer housing that is disposed about a portion of the inner housing is configured to be slideably mounted on the mounting frame. Resilient members are further positioned between the inner housing and outer housing to resist torsional movement of the inner housing and prevent engagement of the inner and outer housings. 
         [0000]    In a preferred form, the inner housing is configured to include a varying wall thickness. By reducing the wall thickness of the inner housing against which the resilient members abut, the outer housing can be reduced in size. As a result, the mounting frame of the spring tensioner can further be reduced in size. In one embodiment, the inner housing has an annular inner surface with varying wall thicknesses. In another embodiment, the inner housing has an annular outer surface portion with flat sections formed therein. 
         [0019]    There are several advantages of having a smaller spring tensioner unit with strength comparable to a larger unit. The first advantage is ease of installation and maintenance on the spring tensioner unit. Additionally, given that spring tensioner units are usually installed below conveyor belts, in areas which there are space restraints, a smaller sized spring tensioner unit would permit a user to install a belt cleaner where it would otherwise be infeasible. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective view of the conveyor belt cleaning apparatus, including a frame, a plurality of belt cleaners, an elongate member, a pair of spring tensioner units in the push-up configuration, and a belt and support frame in phantom; 
           [0021]      FIG. 2  is a perspective view of the spring tensioner unit of  FIG. 1  in the pull-up configuration showing the spring tensioner unit having a notch within the shelf of the mounting frame, a bracketed mounting member positioned in the notch and a cylindrical inner surface of the inner housing of the housing assembly; 
           [0022]      FIG. 3  is a front elevational view of the spring tensioner of  FIG. 1  in the pull-up configuration; 
           [0023]      FIG. 4  is a side elevational view of the spring tensioner of  FIG. 1  in the pull-up configuration showing the inner housing portion extending from the outer housing portion having an annular outer surface; 
           [0024]      FIG. 5  is a back elevational view of the spring tensioner of  FIG. 1  in the pull-up configuration showing the mounting frame having a U-shaped configuration to provide free vertical movement of the elongate pole therethrough; 
           [0025]      FIG. 6  is a perspective view of the spring tensioner of  FIG. 1  in the push-up configuration showing the spring positioned between the housing assembly and bracketed mounting member; 
           [0026]      FIG. 7  is a front elevational view of the spring tensioner of  FIG. 1  in the push-up configuration showing the sleeve member disposed about the threaded rod and extending through the bracketed mounting member; 
           [0027]      FIG. 8  is a perspective view of a prior art belt cleaning apparatus including a plurality of belt cleaners, an elongate pole and a pair of spring tensioner units in the pull-up configuration; 
           [0028]      FIG. 9  is a perspective view of the prior art spring tensioner unit of  FIG. 8  in the pull-up configuration showing the square tube inner housing of the housing assembly and a one-piece mounting frame including a transverse ledge extending along the width of the frame with an aperture therethrough to receive the threaded rod extending from the housing assembly; 
           [0029]      FIG. 10  is a front elevational view of the prior art spring tensioner unit of  FIG. 8  in the pull-up configuration showing the flat outer surfaces of the inner housing, the distance between the rails and ledge of the spring tensioner unit and the distance the threaded rod extends above the ledge; 
           [0030]      FIG. 11  is a side elevational view of the prior art spring tensioner unit of  FIG. 8  in the pull-up configuration; 
           [0031]      FIG. 12  is a perspective view of the prior art spring tensioner unit of  FIG. 8  in the push-up configuration showing the spring located between the housing assembly and the ledge of the mounting frame; 
           [0032]      FIG. 13  is a perspective view of the outer housing of the spring tensioner of  FIG. 1  showing the square housing, the upper and lower guide blocks attached to the upper and lower surfaces of the square housing and the guide block aperture to receive the threaded rod; 
           [0033]      FIG. 14  is a front elevational view of the outer housing of the spring tensioner of  FIG. 1 ; 
           [0034]      FIG. 15  is a side elevational view of the outer housing of the spring tensioner of  FIG. 1 ; 
           [0035]      FIG. 16  is a top plan view of the outer housing of the spring tensioner of  FIG. 1  showing the upper guide block aperture; 
           [0036]      FIG. 17  is a perspective view of the housing assembly of the spring tensioner of  FIG. 1  showing the inner housing, the outer housing, and the resilient members positioned between the inner and outer housings; 
           [0037]      FIG. 18  is a front elevational view of the housing assembly of the spring tensioner of  FIG. 1  showing the annular inner surface of the inner housing; 
           [0038]      FIG. 19  is a back elevational view of the housing assembly of the spring tensioner of  FIG. 1  showing the annular inner surface of the housing assembly and the annular and non-annular outer surfaces of the inner housing; 
           [0039]      FIG. 20  is a side elevational view of the housing assembly of the spring tensioner of  FIG. 1  showing the inner housing extending from the outer housing; 
           [0040]      FIG. 21  is a top plan view of the housing assembly of the spring tensioner of  FIG. 1  showing the aperture of the upper guide block; 
           [0041]      FIG. 22  is a perspective view of the inner housing of the spring tensioner of  FIG. 1  showing the annular outer surface portion and non-annular outer surface portion; 
           [0042]      FIG. 23  is a front elevational view of the inner housing of the spring tensioner of  FIG. 1  showing the annular inner surface and non-annular outer surface portion; and 
           [0043]      FIG. 24  is a side elevational view of the inner housing of the spring tensioner of  FIG. 1  showing the height difference between the annular outer surface which extends from the outer housing and the non-annular outer surface portion which is received in the outer housing. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0044]    In  FIG. 1 , a belt cleaning system is shown having an elongate support member  16  supported on either end by spring tensioners  14 . The spring tensioners are configured to be easily reconfigurable between pull-up  208  and push-up  210  configurations. To accommodate an easy reconfiguration of the spring tensioner, the sprint tensioner includes a detachable portion  120  of a mounting frame  100  to permit easy reconfiguration of the biasing mechanism  200 , such as a spring  204 , in relation to the mounting frame  100 . A further advantage of a reduced overall size of the spring tensioner  14  is realized by a bracket configuration  126  of the detachable mounting member  120  as will be discussed further below. 
         [0045]    As shown in  FIGS. 1-7 , the mounting frame  100  includes a vertical plate portion  104  and a shelf portion  106  extending transversely from the vertical plate portion  104 . The vertical plate portion  104  is configured to be secured to a support frame  12  and includes a pair of parallel leg portions  105  defining a U-shaped configuration of the mounting plate portion  104 . The U-shaped configuration permits the elongate member  16  to extend between the leg portions  105  and travel vertically therebetween. 
         [0046]    A linear guide device  102  of the vertical plate portion  104  provides a connection for a housing assembly  300  and permits linear translation of the housing assembly  300  along the vertical plate portion  104  of the mounting frame  100 . As shown in  FIGS. 1-3 ,  6  and  7 , the mounting frame  100  includes linear guides  108  of the linear guide device  102  positioned along each leg  105  of the mounting frame  100  and the housing assembly  300  includes laterally extending guide blocks  302  and  304  having slide members  303  and  305  to be received in guide channels  108  of the linear guide device  102 . 
         [0047]    The housing assembly  300  has two end positions based on the housing assembly&#39;s linear translation along the mounting frame  100 . In a first end position the housing assembly  300  is fully translated toward a shelf wall  106 . In a second end position the housing assembly  300  is translated to its farthest point from the shelf  106 . Preferably the housing assembly  300  has a limited linear translation distance, such as approximately two inches. 
         [0048]    As shown in  FIGS. 1-7 , the shelf portion  106  includes an opening or notch  122  therein located generally centrally along the shelf portion  106  so that a rod  202  extending from a housing assembly  300  of the spring tensioner  14  extends through the opening  122 . In contrast, the prior art spring tensioners, as shown in  FIGS. 8 ,  9 ,  10  and  12 , include a shelf portion which extends uninterrupted along the width of the mounting frame  100 . 
         [0049]    The detachable mounting member  120  of the shelf  106  is configured to be detachably connected to the shelf portion  106  and extend across the opening  122 . As shown in  FIGS. 2 ,  3 ,  6  and  7 , the shelf  106  includes a pair of apertures  142 , one located on either side of the notch  122 . The mounting member  120  is configured to include a corresponding pair of apertures  140 , through which a fastener  207  can be positioned to detachably connect the mounting member  120  to the shelf  106 . 
         [0050]    To permit the rod  202  to extend therethrough, the mounting member  120  includes an opening  121  therein. As shown in  FIGS. 3 ,  4  and  7 , the rod  202  can include a sleeve portion  123  disposed around the rod  202  for providing reduced friction interaction between the rod  202  and the mounting member  120 . The sleeve portion  123  includes a smooth outer surface for reducing friction as the rod  202  shifts through the opening  121  of the mounting member  120 . The sleeve portion  120  further includes a threaded interior surface for engaging the threaded outer surface of the rod  202 . Finally, the sleeve portion  123  can be secured on the rod  202  by securing members  125 , such as bushings or nuts. 
         [0051]    As shown in  FIG. 1 , the spring  204  is disposed about a portion of the rod  202  and positioned adjacent the portion of the mounting frame  100  through which the rod  202  extends. The spring  204  of the biasing mechanism  200  provides an upward bias on the housing assembly  300  such that belt scrapers  18  attached to the elongate member  16  are biased into engagement with the belt  20 . 
         [0052]    The spring  204  is held in place by a securing or retaining member, such as a nut  206 , threaded on the rod  202  opposite the portion of the mounting frame  100  through which the rod  202  extends. The fastener  206  is adjustable along the length of the rod  202  so as to adjust the elongate support member  16 . The fastener  206  is located on the rod  202  such that, with no loading on the belt  20 , the scrapers  18  are in contact with the lower surface of the belt  20 . By further adjusting the location of the fasteners the bias force applied to the belt  20  by the scrapers  18  is increased or decreased. As shown in  FIGS. 2-7 , the rod  202  has a threaded exterior surface  203  and the fastener  206  has a corresponding threaded inner surface. 
         [0053]    As shown in  FIGS. 2 and 6 , the spring tensioner  14  has a pull-up configuration  208  and a push-up configuration  210 . In the pull-up configuration  208 , as shown in  FIGS. 2-5 , the biasing mechanism  200  is configured such that the mounting member  120  of the shelf  106  is closest to the housing assembly  300 , with the spring  204  disposed about the rod  202  and positioned adjacent to and supported by the mounting member  120  with the fastener  206  positioned adjacent the distal end of the rod  202 . In the push-up configuration  210 , as shown in  FIGS. 6 and 7 , the fastener  206  is positioned about the rod  202  adjacent to the housing assembly  300 . The spring  204  is positioned about the rod  202  between the fastener  206  and the mounting member  120  of the mounting frame  100 . 
         [0054]    The detachable connection between the mounting member  120  and the shelf  106  allows for easy reconfiguration of the spring tensioner  14  from the pull-up configuration  208  to the push-up configuration  210  and vice-versa. In particular, neither the rod  202  or the housing assembly  300  of the spring tensioner  14  require reconfiguration or removal to transition the spring tensioner  14  from the push-up configuration  210  to the pull-up configuration  208  or vice-versa. Reconfiguration is achieved by removing the fastener  206 , spring  204 , and mounting member  120  and repositioning the mounting member  120 , spring  204  and fastener  206  about the rod  202  in an order reverse to which they were removed. 
         [0055]    In another aspect of the invention, the spring tensioner units  14  are configured to be compact in size. The size of a spring tensioner unit  14  is determined based on several criteria, including the size of the mounting frame  100 , the length of the rod  202  of the biasing mechanism  200 , and the size of the housing assembly  300 . In particular, the height of the mounting frame  100  is determined by factors including the distance  144  between the shelf  106  of the mounting frame  100  and the guides  108  for slideably mounting the housing assembly  300  onto the mounting frame  100 . Additionally, the dimensions of the spring tensioner unit  14  are affected by the dimensions of the rod  202 , the spring  204 , the fastener  206 , and the inner housing  330  of the housing assembly  300 . 
         [0056]    The mounting plate  104  has a predetermined height  112  and width  114 . The shelf  106  has a superior surface  138 , an inferior surface  136  and extends transversely along the width of the mounting plate  104 . Preferably, the shelf  106  extends transversely a distance  118  less than the width  114 . In one embodiment, the mounting plate  104  has a width  112  such as 9.5 inches and a height  114  such as 12.75 inches, with the shelf  106  extending transversely a distance  118 , such as less than 4.75 inches. Further, the shelf  106  and the guides  108  are spaced a predetermined distance  144  from one another, as will be discussed further below. 
         [0057]    As shown in  FIGS. 3 and 10 , the length of the rod  202  is determined based on the pull-up configuration  208 . In particular, the length of the rod  202  is selected such that the rod  202  must extend beyond the shelf  106  a distance sufficient to permit attachment of the spring  204  and fastener  206  thereto in the pull-up configuration  208 . 
         [0058]    In addition, as shown in  FIGS. 7 and 12 , the distance  144  between the shelf and the guides  108  of the mounting frame  100  is based on the push-up configuration  210 . The necessary distance  144  between the guides  108  and the shelf  106  is determined so as to permit both the spring  204  and the fastener  206  to be positioned around the rod  202  and between the shelf  106  and the guides  108 . 
         [0059]    As shown in  FIGS. 1-7 , the size of the spring tensioner  14  can be reduced by configuring the mounting member  120  to include a bracket or step configuration  126 . As shown in  FIGS. 3 and 7 , the mounting member configuration includes two vertical sections  128  oriented parallel to one another, the vertical sections  128  connected at one end by a horizontal section  130 , the horizontal section  130  extending between and perpendicular to both of the vertical sections  128 , and a pair of outwardly extending flanges  132  and  134 . The flanges  132  and  134  extend perpendicular to and outwardly from the end of each of the vertical sections  128  opposite the horizontal section  130 . 
         [0060]    Additionally, as described above, the shelf  106  has an opening  122  configured to receive the mounting member  120  therein. In particular, the opening  122  is configured to receive the vertical sections  128  of the mounting member  120 , with the outwardly extending flanges  132  and  134  engaging the shelf  106 . The flanges  132  and  134  of the mounting member  120  are configured to be detachably connected to the shelf  106 . 
         [0061]    In the pull-up configuration  208 , as shown in  FIGS. 2-5 , the flanges  132 ,  134  are detachably connected to the superior surface  138  of the shelf  106  of the mounting frame  100 , with the vertical sections  128  extending through the opening  122 . The spring  204  is oriented around the rod  202 , adjacent to the horizontal section  130  of the mounting member  120 , and positioned between the vertical sections  128  of the mounting member  120 . The spring  204  is captured on the rod  202  between the first horizontal section  130  of the mounting member  120  and the fastener  206 . 
         [0062]    As a result of the bracket configuration  126 , the required length of the rod  202  is decreased by an amount corresponding to the length of the vertical sections  128  of the mounting member  120 . As shown in  FIGS. 3 and 10 , the bracket configuration  126  results in the spring  204  and fastener  206  being positioned closer to the housing assembly  300  than if the mounting member  120  did not include the bracket configuration  126 . As a result of the spring  204  and the fastener  206  being positioned closer to the housing assembly  300 , the rod  202  extending from the housing assembly  202  need not extend as far to allow both the spring  204  and fastener  206  to be disposed about the rod  202  while the spring tensioner  14  is in the pull-up configuration  208 . 
         [0063]    Alternatively, in the push-up configuration  210 , as shown in  FIGS. 6 and 7 , the flanges  132 ,  134  of the mounting member  120  are detachably connected to the inferior surface  136  of the shelf  106  of the mounting frame  100 . The vertical sections  128  of the mounting member  120  extend through the opening  122  of the shelf  106  away from the housing assembly  206 . As shown in  FIGS. 6 ,  7  and  12 , the spring  204  and fastener  206  are disposed about the rod  202  between the mounting member  120  and the housing assembly  300 . In particular, the spring  204  is oriented around the rod  202 , adjacent to the horizontal section  130  of the mounting member  120 , and positioned between the vertical sections  128  of the mounting member  120 . The spring  204  is captured on the rod  202  between the horizontal section  130  of the mounting member  120  and the fastener  206 . 
         [0064]    As a result of the bracket configuration, the spring  204  extends through the opening  122  of the shelf  106  of the mounting frame  100 . The distance  144  requirement determined by the fastener  206  and spring  204  can be accounted for by not only the distance  144  between the guides  108  and the shelf  106 , but also the vertical sections  128  of the mounting member  120 . As a result, the height of the mounting frame  100 , and in particular the distance  144  between the guides  108  and the shelf  106  can be reduced by an amount corresponding to the vertical sections  128  of the mounting member  120 . 
         [0065]    Therefore, the length of the vertical sections  128  of mounting member  120  is taken into account when configuring the dimensions of the mounting frame  100  and the rod  202 . The vertical sections  128  act to reduce the necessary dimensions of the mounting frame  100  and the rod  202 . In the push-up configuration  210 , the distance  144  required between the shelf  106  and the guides  108  of the mounting frame  100  can be reduced by an amount equal to the length of the vertical sections  128  of the mounting member  120 . In the pull-up configuration  208 , the length of the rod  202  can be reduced by an amount equal to twice the length of the vertical sections  128  of the mounting member  120 . Half of the reduction can be accounted for by the bracket  120  as discussed above. The remainder of the rod  202  length reductions can be attributed to the decreased distance  144  between the guides  108  and the shelf  106 , which in turn decreases the necessary length for the rod  202  to extend from the housing assembly  300  and through the opening  122  of the mounting frame  100 . Therefore, the length of the vertical sections  128  results in an overall decrease in the dimensions of the spring tensioner unit  14  equal to at least twice the length of the vertical sections  128 , based on the reduction in the size of the mounting frame  100  and a corresponding reduction in length of the rod  212 . 
         [0066]    In another embodiment, as shown in  FIGS. 13-24 , the housing assembly  300  can be configured to provide a compact housing assembly configuration which, in turn, allows for the mounting frame  100  to have a reduced width and height. 
         [0067]    The housing assembly  300 , as shown in  FIGS. 17-21 , includes an outer housing  310 , an inner housing  330  and a plurality of resilient members  370 . The outer housing  310  is configured to be slideably mounted to the guides  108  of the mounting frame  100 . As shown in  FIGS. 13-16 , the outer housing  330  has four sides  316  with rounded corners  318 . The outer housing  310  is sized to be compact yet sufficiently large to permit the inner housing  330  and resilient members  370  to be located therein. As such, the size of the outer housing  310  is dependent on the size of the inner housing  330  and the resilient members  370 . 
         [0068]    The outer housing  310 , as shown in  FIGS. 13-15 , includes an inner surface  312  for being engaged by the resilient members  370  and extending around the inner housing  330 . The inner housing  330  and outer housing  310  are kept from engaging one another by the plurality of resilient members  370  positioned between the outer surface  350  of the inner housing  330  and the inner surface  312  of the outer housing  310 . An outer surface  314  of the outer housing  310  is configured to have upper and lower guide blocks  302  and  304  mounted thereon. The slide members  303  and  305  of the upper and lower guide blocks  302  and  304  are configured to engage the guides  108  of the mounting frame  100  and connect to the biasing mechanism  200 . As shown in  FIGS. 13 and 16 , the upper and lower guide blocks  302  and  304  of the outer housing  310  each include an aperture  320  configured to receive the rod  202  of the biasing mechanism  200 . 
         [0069]    The inner housing  330  is configured to provide a secure mount for the elongate member  16  and the thereto affixed belt scrapers  18 . As shown in  FIGS. 22-24 , the inner housing  330  of the housing assembly  300  includes a cylindrical inner surface  342  configured to receive the elongate member  16 . The cylindrical inner surface  342  of the inner housing  330 , as compared to a parallelogram-shaped inner surface  344  in the prior art, provides a larger surface area in which to engage the elongate member  16 . By increasing the engageable surface area of the inner housing  330  with a cylindrical surface  342 , and thereby the ring strength of the clamping surface, the elongate member  16  can be more firmly secured within the inner housing  330 . 
         [0070]    As shown in  FIGS. 8-12 , the prior art spring tensioner  15  included an inner housing  331  have a uniform outer surface  333  along its length. In contrast, as shown in  FIGS. 22-24 , the inner housing  330  of the present invention includes a supported outer surface portion  350  configured to be received in the outer housing  310  and a distal outer surface portion  352  for positively securing the elongate support member  16  to the inner housing  330 . As shown in  FIGS. 22 and 24 , the distal outer surface portion  352  of the inner housing  330  includes a plurality of apertures  336 . The apertures  336 , which are preferably threaded, are sized to receive a securing member  338 , such as a set screw, which engages and secures the elongate member  16  within the inner housing  330 . In one embodiment, the thickness  340  of the inner housing  330  not located within the outer housing  310  is 0.5 inches. 
         [0071]    As shown in  FIGS. 17-24 , the supported outer surface portion  350  of the inner housing  330  is configured to be positioned within the outer housing  310  and held in place by a plurality of resilient members  370 . The supported outer surface  350  and the resilient members  370  are configured to mitigate and/or minimize engagement between the inner housing  330  and the outer housing  310  as the inner housing  330  rotates with the movement of the elongate member  16  rotates along its longitudinal axis. As discussed above, any increase in the size of the supported outer surface portion  350  of the inner housing  330  results in a corresponding increase in size of the outer housing  310 , and therefore the housing assembly  300  overall. Additionally, any increase in the dimensions of the housing assembly  300  results in a corresponding increase in the size of the mounting frame  100 . 
         [0072]    As shown in  FIGS. 22-24 , the distal end portion  352  of the inner housing  350  has an annular outer surface  353  with a generally constant thickness. In contrast, the supported portion  350  of the inner housing  330  positioned within the outer housing  310  has an wall  346  of varying thicknesses, the wall  346  being a substantially cylindrical wall with portions removed therefrom, wherein the portions removed result in the wall having flat portions  358  thereon. As shown in  FIGS. 22-24 , the supported portion  350  can include four flat portions  358 , however, more or fewer flat portions  358  are contemplated. Preferably, the inner housing  330  is oriented such that the thinnest sections of the non-cylindrical outer surface  356  are positioned adjacent to the corners  318  of the outer housing  310 . 
         [0073]    The resilient members  370  are positioned between outer housing  310  and the inner housing  330  so that the inner housing  330  does not engage the outer housing  310 . The resilient members  370  are formed to distribute any force on the inner housing  330  to the stronger, thicker sections of the inner housing  330 . Preferably, the resilient members  370  are formed to engage the inner housing  330  and the outer housing  310 . As shown in  FIGS. 17 and 19 , the resilient members  370  are positioned adjacent the flat or thin sections  358  of the inner housing  330 . 
         [0074]    The supported portion  350  of the inner housing  330  and the outer housing  310  are configured to resist migration of the resilient members  370 . The resilient members  370  are sized to be compressed between the inner housing  330  and outer housing  310  after installation. As shown in  FIGS. 22 and 24 , to resist migration of the resilient members  370  the flat sides  358  of the supported portion  350  include grooves  359  therein. The grooves  359  are configured to be engaged by and receive a portion of the compressed resilient members  370 . The sharp corners  361  of the grooves  359  engage the resilient members  370  and tend to keep the resilient member  370  from sliding relative to the outer and inner housings  310  and  330 . Additionally, as shown in  FIGS. 13 and 14 , the outer housing  310  includes detents  363  extending from the inner surface  312 . The detents  363  are positioned to engage the resilient members  370  and resist or mitigate migration of the resilient members relative to the outer and inner housings  310  and  330 . 
         [0075]    In one embodiment of the invention, the depth of the inner housing  354  depends on the torsion resistance qualities of the resilient members  370 . Particularly, as the resilient members  370  have increased torsion resistance, the required depth of the inner housing  354  will decrease. Preferably, the depth of the inner housing  354  is at least 3 inches, more preferably at least 4.5 inches deep. 
         [0076]    While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.