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You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
   The invention relates to the positioning and operation of controller towers for backhoes. More specifically, it relates to a method, system and apparatus for safely and securely positioning controller towers to allow the operator to easily and conveniently move the traditional swivel seat often associated with backhoe cabs into and out of the backhoe operating position. 
   BACKGROUND OF THE INVENTION 
   Backhoes are often equipped with an operator station having a dual position swivel seat which allows the operator to remain seated as he/she pivots between loader and backhoe operations. Such a provision normally requires movable controller towers as controller towers that are properly located for optimum operator convenience and comfort in backhoe operation usually interfere with the operator&#39;s legs and/or with the seat as the operator pivots between backhoe and loader functions. The movable controller towers usually have two basic positions: (1) the stow position which allows the operator to move the swivel seat into and out of the backhoe operating position; and (2) the backhoe operating position which allows the operator to comfortably operate the backhoe when the swivel seat is in the backhoe operating position. 
   Conventional movable controller towers are mounted such that one controller tower is located on each side of the seat, each controller tower being secured in either of the two basic positions via releasable cable and latch mechanisms. 
   SUMMARY OF THE INVENTION 
   The inventors recognize that conventional movable controller towers require a significant amount of extra hardware for cable and latch mechanisms as well as extra labor to produce and assemble the hardware. Further, the additional hardware occupies precious portions of limited available space that could be used for other valuable purposes. Finally, the transverse shaft, commonly shared by both controller towers in some conventional systems, is exposed to the detriments of the environment as it is located under the cab floor; it also reduces functionality in the system by requiring simultaneous movement of the towers. 
   The invention overcomes each of the above mentioned limitations of conventional controller towers via an elegantly simple mechanism. Simple mounting brackets are fixedly attached to portions of the frame or floor on either side of the seat. A shaft, some ball bearings and a snap ring secure each tower to the mounting brackets via a hole in the brackets and serve as a pivot for the independent movement of each tower to each of its positions. A gas filled strut, operatively attached to each tower and corresponding mounting bracket, provides a toggle or over-center effect as each tower is moved from one of its two positions to the other. Thus, an operator may change the position of a tower by pushing or pulling a portion of the tower structure. Adequate extending forces of each strut keeps each of the towers in either of their dual positions, thus eliminating the need for cables and latches to lock the towers. The common rotational shaft, present in some conventional systems, is also eliminated, increasing available space on the underside of the floor for greater access to other components. Finally, the time and cost for parts and labor for each controller tower are reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will be described in detail, with references to the following figures, wherein: 
       FIG. 1  is a view of a work vehicle in which the invention may be used; 
       FIG. 2  is a side view of the invention in an operating position; 
       FIG. 3  is a side view of the invention in a stow position, i.e., the invention is positioned to allow a change in seat position; 
       FIG. 4  is an oblique view of the invention; and 
       FIG. 5  is an exploded view of the invention. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates a work vehicle  10  in which the invention may be used. The particular work vehicle illustrated in  FIG. 1  is a loader backhoe with a single multiple position swivel seat  20 . The multiple positions of the swivel seat  20  include at least a loader operating position and a backhoe operating position and are usually angularly spaced 180° apart. In  FIG. 1 , the swivel seat  20  is shown in the loader operating position. The work vehicle also has two backhoe control assemblies  100 . 
     FIG. 2  illustrates an exemplary embodiment of a backhoe control assembly  100  in the backhoe operating position according to the invention.  FIG. 3  shows the same backhoe control assembly  100  in the stow position. The particular control assembly  100  illustrated is located on the left side of the seat when the seat is in the backhoe operating position. Only this control assembly  100  will be described as its working parts are identical to those of the other control assembly (not shown) on the left side of the seat. The control assembly  100  includes a mounting bracket  110 , a strut assembly  120  operatively attached to the mounting bracket, a movable controller tower  130  operatively attached to the mounting bracket  110  and the strut assembly  120 , a pilot controller assembly  160  and an armrest assembly  140 . 
   The mounting bracket  110  includes a first mounting side  110   a  containing mounting holes  110   d  and  110   e ; a second mounting side  110   b  containing mounting holes  110   f  and  110   g ; and center portion  110   h , including two controller tower stop assemblies  114  and  115 , a hole  112  for attaching the strut assembly  120  to the mounting bracket  110 , and a race  110   c  for pivotally attaching the controller tower  130  to the mounting bracket  110 . The mounting bracket  110  is securely attached to left frame members  170  and  171  as well as the cab floor  180  via mounting holes  110   d ,  110   e ,  110   f  and  110   g  by means well known in the art. See  FIG. 3  for one exemplary method of attachment in which the mounting bracket  110  is attached to right frame members  170  and  171  via bolts  171   a  and nuts  171   b  and to the floor via bolt  180   a , nut  180   b  and via a tab  181  welded to the mounting bracket  110 . Each of the stops  114  and  115  include a bolt  111   a , a spacer  11   b  and a nut  111   c.    
   The strut assembly  120  includes a conventional gas filled strut  121  having a first end  121   a  and a second end  121   b . The first and second ends  121   a ,  121   b  are constructed for attachment to working structures in manners well known in the art via eyelets  122 , each eyelet having three dimensional rotation characteristics. 
   The movable controller tower  130  includes a mounting plate  131  having two square positioning holes  133  for positioning a first stiffening rib  137   a  and a square hole  136  for positioning rotationally fixed screw  126 . Attached to the mounting plate, via welding are a hose harness  137   a , a second stiffening rib  137   b , a third stiffening rib  137   c , a pivot shaft  134  and a controller cage  150 . The stiffening ribs  137   a ,  137   b  and  137   c  are positioned as shown in  FIGS. 1 ,  2 ,  3 , and  4  and welded to the mounting plate by means well known in the art. The controller cage  150  houses the pilot controller assembly  160  and restricts/constrains all movement of the pilot controller assembly  160  as a whole via methods and structures well known in the art. 
   The armrest assembly  140  includes a strong and rigid support arm  142  having a pivot hole  144  and an adjustment hole  143 . The support arm  142  may be constructed of a metal such as steel. The armrest assembly  140  also includes a soft surface mounted to the support arm  142 . The soft surface may be provided by a padded roller  141  rotationally mounted to the support arm  142  as in the embodiment described and illustrated herein (see  FIG. 4 ) or a conventional soft surface mounted via a suitable means already known in the art. The support arm  142  is pivotally mounted to the controller cage via a bolt  146 , a spacer  148 , the pivot hole  151   a  in a side plate  151  of the controller cage  150  and a nut (not shown). The armrest  140  is rotationally constrained by a screw  149 , a slotted hole  144  and a nut arm  145 . The armrest  140  may be rigidly held in place and prevented from rotating about bolt  146  by sufficiently tightening the nut arm  145 . Additionally, the rotational position of the support arm  142  may be adjusted along the length of the adjustment hole  143  by loosening the nut arm  145  sufficiently to allow movement. 
   The mounting plate  131  is operatively attached to the first end  121   a  of the gas filled strut  121  via the square hole  136 , the screw  126 , the spacer  129 , the eyelet  122   a , a spacer  123  and the nut  124 . The second end  121   b  of the gas filled strut  121  is attached to the mounting bracket  110  via nut  124 , bolt  125 , hole  112 , eyelet  122   b  and three spacers  123 ,  123 ,  123  as shown in  FIG. 4 . Thus, the movable controller tower  130  is operatively connected to the mounting bracket  110  via the gas filled strut  120 . 
   The mounting plate is rotationally attached to the mounting bracket  110  via the pivot shaft  134 , ball bearings  191 ,  192 , a spacer  193 , a snap ring  194  and the race  110   c . During assembly of the mounting plate  131  to the mounting bracket  110 , ball bearings  191  and  192  press fit into the hole provided by the race  110   c . The pivot shaft  134  is then slip fitted into the ball bearings  191  and  192 , the spacer  193  is fitted over the pivot shaft  134  and, finally, the snap ring  194  is assembled to the pivot shaft  134  via shaft groove  135 . Thus, movement of the mounting plate  131  at the pivot shaft  134  is constrained by the mounting bracket  110  in all directions excepting a rotational motion about an axis of the pivot shaft  134 . 
   The gas filled strut  120  is compressive and is assembled to the controller tower  130  and the mounting bracket  110  such that it is shortest at an intermediate position between the stow and backhoe operating positions of the controller tower  130  (see  FIGS. 2 and 3 ). Thus, the gas filled strut  120  acts as a toggle mechanism which resists motion of the controller tower  130  from a first or a second position toward the intermediate position and enhances motion of the controller tower  130  from the intermediate position toward the first or the second position. Although the load applied by the gas filled strut  120  increases with decreases in its overall length, the portion of the load applied to resist movement of the controller tower  130  decreases as the angle of the strut axis approaches 90° with respect to the mounting bracket base  113 . As a result of this arrangement, resistance to any motion of the controller tower  130  toward the intermediate position is highest at the stow and backhoe operating positions. Resistance to movement of the controller tower  130  toward the intermediate position tends to decrease as the distance between the position of the controller tower  130  and the intermediate position decreases. The gas filled strut  120  acts to push the controller tower  130  away from the intermediate position with a force that is proportional to the distance of the controller tower  130  from the intermediate position. 
   Resistance to movement from the stow position or the backhoe operating position is sufficient to keep the controller tower  130  in that position. The application force required to overcome the resistance may be preset at a minimum of, for example, 20 pounds. 
   The stops  114  and  115  define each of the rotational limits for movement, i.e., the stow position and the operating position, respectively, for the controller tower  130 . In the stow position, surface  131   a  contacts the stop  114  and prevents further movement of the controller tower  130  away from the intermediate position. In the operating position, the surface  131   b  contacts the stop  115  preventing further movement of the controller tower  130  away from the intermediate position. 
   Having described the illustrated embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.

Summary:
A controller tower positioning system for a work vehicle for securing the controller tower to one of at least two positions. The system employs a mounting bracket fixed to the floor or a frame member of the work vehicle, a movable controller tower rotatably mounted to the mounting bracket and a resistive element strategically mounted to the controller tower and the mounting bracket to provide resistance to movement away from either of the two positions and a toggle effect as the controller tower is moved from one of the two positions to the other. The controller assembly is physically restrained at the free end of the controller tower.