Abstract:
A telescoping steering column is provided with a simple means to allow ease of movement of a telescoping steering shaft through a plurality of positions. This is accomplished by placing a biasing component on an exterior of a movable portion of the steering column to bias the movement of that portion.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to steering column support structures for an automobile, and more particularly to a telescoping steering column with a spring assist mechanism to provide a smooth telescoping movement. 
     BACKGROUND 
     A steering column, including the steering shaft, provides a mechanism to translate the movement of the steering wheel to the wheels of an automobile. The movement of the steering wheel is an integral and continuous way in which an automobile driver interacts with the automobile. This being the case it is desirous to provide a means to allow the driver to adjust the position of the steering wheel so as to allow for maximum comfort and driving enjoyment. However, generally, the steering shaft is rigid and fixed allowing for no repositioning of the steering wheel once the steering column has been installed into the automobile. 
     It is known in the art, however, to provide a mechanism that would allow the user of the automobile the ability to change the relative orientation of the steering wheel for his optimal comfort. The mechanism provides a means to lock and unlock the position of the steering column and to move the steering column closer or further from the drivers body. Many of these mechanisms, however, do not provide a means to counter the weight and frictional forces of the steering column during movement. Generally the prior art simply provides a means to slidably engage an upper shaft with a lower shaft and a means to unlock the two shafts to allow movement of the upper shaft. 
     One prior art reference discloses a method to attempt to counteract the weight, friction, and other forces acting against movement of the steering column. U.S. Pat. No. 6,035,740 discloses a gas compression spring placed within the steering shaft. The gas compression spring is installed in such a fashion so as to allow for easier of movement of the steering shaft. However, this invention requires an extensive retooling of the steering shaft to allow for the introduction of such a gas compression spring. Other similar disclosures provide for a spring placed internally in the steering column to counteract the weight of the steering column during movement of the column. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a simple means to allow ease of movement of a telescoping steering shaft through a plurality of positions into and out of a steering column. The present invention is added to the exterior of the steering column and includes a wound spring in a small cassette housing that counteracts the weight of the steering column. However, the minimal size and weight of the cassette do not require the addition of extra space or weight to the steering column assembly. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of the upper mounting bracket of a telescoping steering column according to the principles of the present invention assembled to the instrument panel and the frame member of the automobile. 
     FIG. 2 is a perspective view of the upper mounting bracket of a telescoping steering column according to the principles of the present invention. 
     FIG. 3 is a detail view of the upper mounting bracket with a cut-away section to reveal the spring cassette apparatus according to the principles of the present invention. 
     FIG. 4 is a plan view of the spring cassette according to the principles of the present invention. 
     FIG. 5 is a cross-sectional view of the upper mounting bracket taken along the line  5 — 5  of FIG.  1 . 
     FIG. 6 is a perspective view of the upper mounting bracket further illustrating the placement of several sections of the steering shaft and their interactions. 
     FIG. 6 a  is a cross-sectional view of the steering shaft indicating the interlocking of the spline on a section of the steering shaft. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a mounting bracket  12  in its assembled orientation with the support bracket  14  and the instrument panel  15 . 
     Referring to FIG. 1 the mounting bracket  12  includes a main body  20  through which a bore  16  is formed. The bore  16  houses the steering shaft (shown in FIG.  6 ). Two pair of mounting flanges  10   a,    10   b  are disposed on opposite sides of the main body  20 . Such mounting flanges  10   a,    10   b  are for attaching the mounting bracket  12  to the support bracket  14 . The mounting bracket  12  has two members, a rearward bracket member  18  and a forward bracket member  11 . Only the forward bracket member  11  is directly affixed to the support bracket  14 . The rearward bracket member  18  is affixed to the forward bracket member  11  through mounting pins  26  which extend through the mounting pillars  28 . The mounting pins  26  are further attached to the rearward bracket member  18  through the spring cassette  31  (shown in FIG. 3) placed in the channel  24  defined in rearward bracket member  18  of mounting bracket  12 . The channel  24  allows rearward bracket member  18  to be moved axially relative to forward bracket member  11 . A lever  22  is attached to a catch pin  42  (indicated in FIG. 5) which holds a selected position of the rearward bracket member  18 . Furthermore, stop pins  30  (best shown in FIG. 1) ensure a maximum travel distance of the rearward bracket member  18 . 
     FIG. 2 is a perspective view of the mounting bracket  12  alone including the rearward bracket member  18  and the forward bracket member  11 . The main body  20  of forward bracket member  11  includes a bore  16  through which a steering shaft is inserted. The rearward bracket member  18  is attached to the forward bracket member  11  through the mounting pins  26  (shown in FIG. 1) which are affixed to the mounting pillars  28 . An actuating lever  22  is mounted to one of the mounting pillars  28 . Further, the channel  24  guides the movement of the rearward bracket member  18  and the stop pins  30  define the maximum movement of the rearward bracket member  18 . 
     FIG. 3 is a perspective detail view of the rearward bracket member  18  with a cut-away to fully show the spring cassette  31 . The rearward bracket member  18  includes a pair of channels  24  on opposite sides of the main body  20  (only one is shown for explanation). Spring cassette housing  31  is disposed within channel  24 . With reference to FIGS. 3 and 4, the spring cassette housing  31  includes a major cassette  32  which houses the minor cassette  40  in an internal track. The minor cassette  40  includes a tension spring  34  wound around a center cylinder  36  with a leading end  38  of the tension spring  34  affixed to a holding pin  37 . FIGS. 3 and 4 show the minor cassette  40  in its extended position with the rearward bracket member  18  in the retracted position. When released from external forces the tension spring  34  would draw the minor cassette  40  towards the holding pin  37  where the end of the leading edge  38  of the spring  34  is affixed. This motion would move the rearward bracket member  18  to an extended position relative to the forward bracket member  11 , in addition the steering wheel, which is attached to the rearward bracket member  18 , would also move. The tension spring  34  works to counteract the forces that hinder movement of the steering wheel by the user. The tension spring  34  can be designed to meet any force requirements. 
     FIG. 5 is a cross-sectional view taken along line  5 — 5  from FIG.  1 . The engagement between the main body  20  of the forward bracket member  11  and rearward bracket member  18  is shown in cross-section. Many of the components have equivalents on either side of the main body  20 . The bore  16  through the main body  20  receives a steering shaft  53  (shown in FIG.  6 ). The channels  24  are formed into both sides of the rearward bracket member  18 . The channels  24  contain the spring cassettes  31   a  and  31   b.  The spring cassettes  31   a  and  31   b  further include the minor cassettes  40   a  and  40   b  which house the tension springs  34   a  and  34   b.  Spring cassettes  31   a  and  31   b  include plastic internal guide tracks  33  which slidably support minor cassette  40   a,    40   b  within the major cassette housings  32 . The tension springs  34   a  and  34   b  are wound springs wound around a central cylinder  36  through which the mounting pins  26   a  and  26   b  are slidably received. The mounting pins  26   a,    26   b  are not fixedly attached to the main body  20  of the rearward bracket member  18 , however they are fixedly attached to the mounting pillars  28   a  and  28   b  which are a part of the forward bracket member  11 . 
     The rearward bracket member  18  is allowed to move axially relative to the forward member  11 . The mounting pins  26   a  and  26   b  support the minor cassette  40   a,    40   b  while the tension springs  34   a  and  34   b  translate a force to the rearward bracket member  18  thus assisting movement of the rearward bracket member  18 . The lever  22  allows the user to selectively engage and disengage locking pin  42  from a plurality of positioning slots  43  spaced axially along main body  20 . Lever  22  is pivotally or otherwise connected to the mounting pillar  28  to allow activation of said lever in a pre-selected direction to cause pin  42  to disengage from slot  43 . While the positioning pin  42  is disengaged the rearward bracket member  18  may be repositioned relative to the forward bracket member  11 . Once a comfortable position is selected by the user the positioning pin  42  is re-engaged in a new positioning slot  43 . A plurality of positioning slots  43  may be created in the main body  20  of the forward bracket member  11  to allow for a plurality of selectable positions. 
     FIG. 6 shows a perspective view of the mounting bracket  12  including a main body  20  with a steering shaft  53 , partially shown in phantom, extending through the bore  16 . Steering shaft  53  is supported for rotation relative to mounting bracket  12  by appropriate bearings such as  52 . The steering shaft  53  includes at least two main sections the rearward shaft section  54  and the forward shaft section  56 . A steering wheel (not shown) is mounted on a first terminal end of the rearward shaft section  54 . The second terminal end of rearward shaft section  54  inserts into a first terminal end of the forward shaft  56 . The second terminal end of the forward shaft section  56  connects to a steering linkage through connections not relevant to this invention. The rearward shaft section  54  and the forward shaft section  56  are not fixedly attached to one another, rather they slidably interconnect through splines  58 . In this way as the rearward shaft section  54  is able to move axially relative to the forward shaft section  56 , yet still allow for a continuous rotational connection therebetween. Turning briefly to FIG. 6 a  a cross-section along line  6   a — 6   a  indicates a detail of the spline connection  58 . The rearward shaft section  54  being the inner core and the forward shaft section  56  being the outer portion. 
     Returning specifically to FIG. 6 the workings of the telescoping mechanism, can now be seen. The spline connection  58  of the steering shaft  53  allows for axial displacement of the rearward shaft section  54  without disengaging the steering shaft  53  from the steering wheel. Furthermore, the rearward bracket member  18  is interconnected with the forward bracket member  11  through the telescoping mechanism including the spring cassette  31  (shown in FIG.  4 .), mounting pin  26  and mounting pillars  28 . The mounting pins  26  are affixed to the mounting pillars  28  thereby creating a stable platform to hold the rearward bracket member  18 . The mounting pins  26  then interconnect with the spring cassette  31 , thus allowing for a transference of the force create by the spring to the rearward bracket member  18  allowing for ease of movement of the rearward bracket member  18 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.