Abstract:
A tensioner comprising a base comprising a first portion, an arm comprising a second portion, the arm pivotally connected to the base, a pulley journalled to the arm, a resilient member compressively disposed between the first portion and the second portion, the resilient member comprising a gap within which the first portion and the second portion are disposed, and the resilient member comprising a bore, the bore engaging the arm.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a tensioner, and more particularly, to a tensioner comprising a resilient member within which a base first portion and an arm second portion are cooperatively disposed. 
       BACKGROUND OF THE INVENTION 
       [0002]    In numerous applications where endless power transmission devices are employed it is often desirable or necessary to control the tension in such devices during movement thereof around associated sheaves, pulleys, sprockets or the like, to assure optimum operating efficiency. 
         [0003]    Numerous tensioning devices such as belt tensioning devices have been proposed heretofore and most of these devices employ metal spring devices, hydraulic devices, or pneumatic devices to provide the tensioning action whereby such devices are comparatively complicated and expensive and require considerable maintenance. Accordingly, there is a need for a simple and inexpensive tensioning apparatus capable of providing reliable performance over an extended service life. 
         [0004]    Representative of the art is U.S. Pat. No. 3,975,965 (1976) which discloses a tensioning apparatus for an endless power transmission device is provided and utilizes the elastic properties of an elastomeric material to provide the tensioning action and such apparatus is supported adjacent the endless power transmission device to be tensioned and has components thereof operatively associated with the elastomeric material and with the device. 
         [0005]    What is needed is a tensioner comprising a resilient member within which a base first portion and an arm second portion are cooperatively disposed. The present invention meets this need. 
       SUMMARY OF THE INVENTION 
       [0006]    The primary aspect of the invention is to provide a tensioner comprising a resilient member within which a base first portion and an arm second portion are cooperatively disposed. 
         [0007]    Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings. 
         [0008]    The invention comprises a tensioner comprising a base comprising a first portion, an arm comprising a second portion, the arm pivotally connected to the base, a pulley journalled to the arm, a resilient member compressively disposed between the first portion and the second portion, the resilient member comprising a gap within which the first portion and the second portion are disposed, and the resilient member comprising a bore, the bore engaging the arm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with a description, serve to explain the principles of the invention. 
           [0010]      FIG. 1  is a perspective view of the tensioner. 
           [0011]      FIG. 2   a  is a perspective view of the base. 
           [0012]      FIG. 2   b  is a side view of the base. 
           [0013]      FIG. 3  is a perspective view of the resilient member. 
           [0014]      FIG. 4   a  is a perspective view of the arm. 
           [0015]      FIG. 4   b  is a perspective bottom view of the arm. 
           [0016]      FIG. 5  is a perspective view of the sleeve. 
           [0017]      FIG. 6  is a perspective view of the retainer. 
           [0018]      FIG. 7  is an exploded view. 
           [0019]      FIG. 8  is a bottom view of the tensioner arm. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]      FIG. 1  is a perspective view of the tensioner. Tensioner  100  comprises a base  10 . Arm  20  is pivotally connected to base  10 . Disposed between arm  20  and base  10  is resilient member  30 . Resilient member  30  biases arm  20  against a belt (not shown) in order to apply a force (load) to the belt. 
         [0021]    A pulley  40  is journalled to the arm  20 . The belt (not shown) engages a surface  41  of pulley  40 . Pulley  40  rotates about bolt  42  on bearing  43 . 
         [0022]    Arm  20  pivots about post  11 . Retainer  50  is used to retain arm  20  in proper operational connection to base  10  and resilient member  30 . A low-friction sleeve  60  is disposed between arm  20  and post  11 . 
         [0023]      FIG. 2   a  is a perspective view of the base. Base  10  comprises a post  11  which extends therefrom. Portion  12  extends upward from base  10  into recess  13 . Portion  12  is not connected to the length of post  11  so that portion  12  does not interfere with skirt  22  or sleeve  60 . 
         [0024]    Tab member  14  projects from base  10  to engage a mounting surface, such as an engine block (not shown). Tab member  14  prevents rotation of base  10  during operation and assures proper orientation during final assembly on a mounting surface. 
         [0025]      FIG. 2   b  is a side view of the base. Gap  120  is disposed between portion  12  and post  11  to allow clearance for skirt  22  and sleeve  60 . 
         [0026]      FIG. 3  is a perspective view of the resilient member. Resilient member  30  substantially describes a “C” shape. As such resilient member  30  comprises a gap  31  which cooperatively engages portion  12  in base  10  and portion  21 . Resilient member further comprises a bore  32  which engages arm skirt  102 . Resilient member  30  also engages base  10  within recess  13  and arm  20 . Resilient member  30  further comprises projections  33  which engage arm  20  and base  10 . Projections  33  are used to bias arm  20  in to the proper operating position, and thereby maintain a proper pulley position with respect to a belt (not shown). 
         [0027]    Resilient member  30  comprises any known natural or synthetic rubber material, or suitable combination of the two. The spring rate of resilient member  30  may be selected by changing the thickness, height or durometer of the material. 
         [0028]      FIG. 4   a  is a perspective view of the arm. Portion  21  extends from arm  20  so as to extend within gap  31  in resilient member  30 . Portion  21  engages resilient member  30  so as to compress resilient member  30 . 
         [0029]      FIG. 4   b  is a perspective bottom view of the arm. Skirt  22  extends toward base  10 . Bore  32  of resilient member  30  engages skirt  22 . See  FIG. 8 . 
         [0030]      FIG. 5  is a perspective view of the sleeve. Sleeve  60  is cylindrical in shape. Sleeve  60  extends between arm  20  and post  11 . Sleeve  60  is a low friction material in order to facilitate movement of arm  20 . In an alternate embodiment, sleeve  60  may comprise a predetermined coefficient of friction with the arm  20  whereby a movement of arm  20  is damped, so as to damp arm oscillations. 
         [0031]      FIG. 6  is a perspective view of the retainer. Retainer  50  engages post  11  to hold arm  20  and resilient member  30  in proper position in base  10 . 
         [0032]      FIG. 7  is an exploded view. In operation, a belt (not shown) is engaged with pulley  40 . As a belt tension changes the arm  20  pivots about base  10 . Since resilient member  30  is captured between portion  12  and portion  21 , any pivotal movement of arm  20  whereby a belt tension (load) is increased is resisted through compression of resilient member  30 . This is because movement of arm  20  causes portion  21  to move toward portion  12  in recess  13 . 
         [0033]    In a predetermined operating condition, for example, in an “unloaded” position portion  12  is held in “back to back” contact with portion  21  by resilient member  30 . 
         [0034]    Dust covers  44  protect bearing  43  from debris. 
         [0035]      FIG. 8  is a bottom view of the tensioner arm. In this view portion  21  is in contact with portion  12 . Bore  32  of resilient member  30  is engaged about skirt  22 . Portion  12  and portion  21  are each disposed in resilient member gap  31 . Sleeve  60  is disposed radially inward of skirt  22 , namely, sleeve  60  is between skirt  22  and post  11 . Skirt  22  and sleeve  60  are disposed within gap  120  in order to pivotally engage post  11 . 
         [0036]    Although a form of the invention has been described herein, it will be obvious to those skilled in the art that variations may be made in the construction and relation of parts without departing from the spirit and scope of the invention described herein.