Abstract:
An apparatus includes an outer rectangular tube and an inner rectangular tube. The inner rectangular tube and the outer rectangular tube are movable in relation to each other. In some versions a gas spring is positioned within the outer rectangular tube and the inner rectangular tube. In some versions, the apparatus further comprises a pair of inner bearing blocks operable to change the coefficient of friction between the inner rectangular tube and the outer rectangular tube. In some versions, the apparatus further comprises an outer bearing block assembly operable to change the coefficient of friction between the outer bearing block assembly and the inner rectangular tube.

Description:
PRIORITY 
       [0001]    This applications claims priority of U.S. Provisional Patent Application titled “Adjustable Column System and Method,” Ser. No. 61/320,933, filed on Apr. 5, 2010, the disclosure of which is incorporated by reference in its entirety. 
     
    
     FIELD 
       [0002]    Embodiments of the present invention relate, in general, to lift columns, and, in particular, to adjustable lift columns having adjustable bearings. 
       BACKGROUND 
       [0003]    A gas spring is a type of spring that, unlike a typical metal spring, uses a compressed gas, contained in a cylinder and variably compressed by a piston, to exert a force. Gas springs are used frequently in automobile construction, where they are commonly used to support the weight of vehicle doors while they are open. They are also used in furniture, medical, and aerospace applications. In particular, gas springs have been adapted for use in adjustable lift columns for furniture and medical applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present disclosure, and together with the description serve to explain the principles of the invention; it being understood, however, that the described embodiments are not limited to the precise arrangements shown. In the drawings, like reference numerals refer to like elements in the several views. In the drawings: 
           [0005]      FIG. 1  is a plan view of one version of a lift column having an outer support tube, an inner tube, a top mounting flange, a lower mounting attachment, and an outer bearing block assembly. 
           [0006]      FIG. 2  is an exploded view of the lift column of  FIG. 1  showing a gas spring retained within the inner tube and adjustable inner bear blocks configured to retain the gas spring and to translate within the outer support tube. 
           [0007]      FIG. 3  is a more detailed view of the lift column of  FIG. 1  showing the relationship between the outer support tube, the inner tube, the inner bearing blockings and the outer bearing block assembly. 
           [0008]      FIG. 4  is a perspective view of one portion of the outer bearing block assembly of the lift column of  FIG. 1 . 
           [0009]      FIG. 5  is a top view of the outer support tube of the lift column of  FIG. 1 . 
           [0010]      FIG. 6  is a top view of the inner tube of the lift column of  FIG. 1 . 
           [0011]      FIG. 7  is bottom perspective view of the inner tube of the lift column of  FIG. 1  showing the relationship between the inner bearing blockings and the outer tube, where  FIG. 7  further illustrates an adjustment tool for the inner bearing blockings. 
           [0012]      FIG. 8  is a more detailed side view of the relationship between the inner bearing blockings and the adjustment tool. 
           [0013]      FIG. 9  is a perspective view of the base mounting of the lift column of  FIG. 1 . 
           [0014]      FIG. 10  is a perspective view of the adjustment mechanism associated with the gas spring of the lift column of  FIG. 1 . 
           [0015]      FIG. 11  is a perspective view of an alternate version of an adjustment mechanism that may be associated with the gas spring of the lift column of  FIG. 1 . 
           [0016]      FIG. 12  is a side view of the alternate adjustment mechanism of  FIG. 11 . 
           [0017]      FIG. 13  is a perspective view of an alternate version of a base mounting for the lift column of  FIG. 1  showing the attachment of the gas spring to the outer support member. 
           [0018]      FIG. 14  is a perspective view of an alternate version of a base mounting for the lift column of  FIG. 1  showing the outer support member integral with a base flange. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Embodiments described in this disclosure comprise a column assembly for raising and lowering various articles such as medical equipment, medical carts computer carts, furniture, tables, workstations, TV/monitors, monitor arms and medical equipment. In one embodiment the column assembly is not rotational and is configured to provide support for variable side loads. 
         [0020]    Referring to  FIG. 1 , one version of a lift column  10  is shown having an outer support member  12 , an inner tube  14 , a top mounting flange  16 , a lower mounting attachment  18 , and an outer bearing block assembly  20 . The inner tube  14  in configured to translate relative to the outer support member  12  along a central axis A-A. Translation of the inner tube  14  relative to the outer support member  12  increases or decreases the height of the lift column  10  depending on the direction of translation along axis A-A. Thus, the lift column  10  may be used in any suitable application, such as medical applications, to raise a lower devices mounted on the lift column  10 . The inner tube  14  and outer support member  12  have substantially square-shaped cross-sections configured to resist rotational movement between the two components. Thus, the inner tube  14  has unidirectional movement along axis A-A as it translates within the outer support member  12 . Support flanges may be attached or integral with the top and/or bottom portions of the column assembly to support equipment, a moveable base, or any other column feature. 
         [0021]    The top mounting flange  16  is configured for attachment to any suitable component such as, for example, a medical device for which height adjustment is desirable. The lower mounting attachment  18  is configured to mate with any suitable base that serves to support the lift column. The base (not shown) may be wheeled, incorporate a swivel, be fixed to a structure, or have any other suitable configuration. It will be appreciated that the configuration of the column assembly can be inverted such that the outer support column has a top mounting flange and the inner tube is attached or integral with a base. 
         [0022]      FIG. 2  illustrates an exploded view of the lift column  10  having a gas spring  22  configured to adjust the height of the lift column  10  by translating the inner tube  14  relative to the outer support member  12 . The gas spring  22  includes a jacket tube  24  that is coupled to the lift column  10  at the base plate  18  and a piston rod  26  that is coupled to the inner tube  14  via a mounting member  28 . As illustrated in  FIG. 2 , the mounting member  28  of the piston rod  26  is coupled to the upper portion of the inner tube  14  such that translation of the piston rod  26  relative to the jacket tube  24  translates the inner tube relative to the outer support member  12 . As illustrated, the mounting member  28  and the jacket tube  24  are coupled to the inner tube  14  and base member  18 , respectively, with a pin  30 ,  32 . 
         [0023]    Still referring to  FIG. 2 , the outer bearing block assembly  20  is coupled to the outer support member  12  with bolts  34  configured to engage channels  36  (shown in  FIG. 5 ) running parallel to the axis A-A of the lift column  10 . A pair of inner bearing blocks  38 ,  40  are coupled to the lower end of the inner tube  14  with bolts configured to engage channels  44  (shown in  FIG. 6 ) running parallel to the axis A-A of the lift column  10 . The relationship between the outer bearing assembly  20  and the inner bearing blocks  38 ,  40  will be described in more detail with reference to  FIG. 3 . 
         [0024]    With reference to  FIGS. 3 and 4 , the outer bearing block assembly  20  is shown having a first portion  48  and a second portion  50  configured to mate to form a square-shaped bushing. With reference to  FIG. 4 , the first portion  48  forms half of the outer bearing block assembly  20  and includes a base portion  52  having three spaced apart bolt holes  54 . The ends  56 ,  58  of the first portion  48  are approximately half the thickness of the assembled outer bearing block are designed to mate with the second portion  50  to form an outer bearing block assembly  20  having a substantially uniform thickness. The second portion  50  is identical to the first portion  48  and is engaged with the first portion  48  by inverting the second portion  50 , aligning the bolt holes associated with the ends of the first and second portions, and inserting bolts  34  to couple the first and second portions together. The bolts  34  are also used to couple the complete bearing block assembly  20  to the outer support member  12  via channels  36 . 
         [0025]    Still referring to  FIGS. 3 and 4 , the holes  54  associated with the ends  56 ,  58  of the first portion  48  and the second portion  50  have a larger internal diameter than the outer diameter of bolts  34 . In particular, the overlapping ends  56 ,  58  of the first portion  48  and the second portion  50  have a larger internal diameter than the bolts  34  such that the first portion  48  and the second portion  50  may be adjusted and spaced apart at a desired distance before coupling the portions together to form the complete outer bearing block assembly. Adjusting the position of the coupling between the first and second portions  48 ,  50  correspondingly alters the internal circumference of the outer bearing block assembly that directly contacts the inner tube  14  translating therethrough. Thus, by altering the position of the portions of the outer bearing block assembly  20  the coefficient of friction between the outer bearing block assembly  20  and the inner tube  14  can be tuned to provide a desirable resistance. It will be appreciated that variations in spacing, thickness of the components, and the like, may be altered to provide the desired coefficient of friction. 
         [0026]    With reference to  FIGS. 7 and 8 , the inner tube  14  is coupled to a pair of identical inner bearing blocks  38 ,  40 . The inner bearing blocks are substantially square-shaped plates lying adjacent and parallel to one another. Each of the inner bearing blocks  38 ,  40  includes a number of holes  60  through which bolts  42  are inserted into channels  44  (shown in  FIG. 6 ). Similar to the outer bearing block assembly  20 , the inner bearing blocks  38 ,  40  are configured to be adjusted in order to provide a desirable coefficient of friction between the inner tube  14  and the outer support member  12 . The holes  60  in the inner bearing blocks  38 ,  40  have an internal diameter greater than the outer diameter of the bolts  42 . Referring to  FIG. 8 , the inner bearing blocks  38 ,  40  include slots  62  projecting laterally from a central hole  64  configured to accept the gas spring  22 . 
         [0027]    During assembly, the inner tube  14  is inserted into the outer support member  12  as shown in  FIG. 7 . Once inserted, the inner bearing blocks  38 ,  40  are placed adjacent the bottom end of the inner tube  14  within the outer support member  12  such that the holes  60  are aligned with the channels  44  shown in  FIG. 6 . A tool  66  having a flattened distal end  68  corresponding to the slots  62  is then inserted into the slots  62  of the inner bearing blocks  38 ,  40 . As shown in  FIG. 8 , the tool  66  is then pivoted such that the inner bearing blocks  38 ,  40  move relative to one another and contact the inner surface of the outer support member  12 . The degree with which the tool  66  is pivoted adjusted alters the force of the inner bearing blocks  38 ,  40  pressing on the outer support member  12  and, thus, allows for the coefficient of friction between the inner tube  14  and the outer support member to be adjusted. When the inner bearing blocks  38 ,  40  are properly positioned the bolts  42  are inserted into the holes  60  to affix the inner bearing blocks  38 ,  40  in the proper position. 
         [0028]    Generally, the outer bearing block assembly  20  and the inner bearing blocks  38 ,  40  allow the coefficient of friction and, thus, the “slop” or motion of the inner tube  14  relative to the inner tube  12  to be controlled. The adjustability of the outer bearing block assembly  20  and inner bearing blocks  38 ,  40  allows for the use of molded parts, rather than machined parts with tight tolerances, to be used. Furthermore, the adjustability of the components allows for the system to be retuned after periods of extended use rather than requiring the lift column  10  to be outfitted with new bearings. Providing universal components decreases the cost of the bearings and reduces costs associated with replacing worn bearings over the life of the column. 
         [0029]      FIG. 9  illustrates the mounting attachment  18  of the outer support member  12 , where the jacket tube  24  of the gas spring is coupled to the mounting attachment  18  with a pin  32 . The mounting attachment  18  is configured for attachment to any suitable base (not shown). 
         [0030]      FIG. 10  illustrates attachment of the mounting member  28  of the piston rod  26  to the inner tube  14  with a pin  30 . Associated with the mounting member  28  is an adjustment assembly  80  for the gas spring  22 , which is configured to raise and lower the gas spring  22 . The adjustment assembly  80  includes an arm  82  associated with a valve (not shown) of the gas spring  22 . A co-axial cable  84  is attached to the arm  82  at one end and is associated with an actuator (not shown) at a second end, where operation of the actuator adjusts the position of the arm  82  via the co-axial cable  84  to raise and lower the gas spring  22 . As illustrated, a sheath  86  of the co-axial cable  84  is affixed directly to the inner tube  14 , thereby securing the co-axial cable to the lift column  10 . 
         [0031]      FIGS. 11 and 12  illustrate an alternate version of a mounting member  128  of the piston rod  26  to the inner tube  14  with a pin  130 . Associated with the mounting member  128  is a levered adjustment assembly  180  for the gas spring  22 , which is configured to raise and lower the gas spring  22 . The levered adjustment assembly  180  includes a lever  182  associated with a valve (not shown) of the gas spring  22 . Operation of the lever  182  adjusts the position of the column assembly by raising and lowering the gas spring  22 . It will be appreciated that any suitable actuation means for the column assembly is contemplated. 
         [0032]      FIG. 13  illustrates an alternate mounting attachment  118  of the outer support member  12  and jacket tube  24 , where the jacket tube  24  has a flange  122  having a through hole through which the gas spring  22  is coupled to the outer support member  12  via a pin  120 . of the gas spring is coupled to the mounting attachment  18  with a pin  32 .  FIG. 14  illustrates an alternate version of the mounting attachment  118  shown integral with a base flange  124 . 
         [0033]    Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by those of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings.