Abstract:
An adjustable height support column for an examination table/chair is disclosed. The column includes nesting sleeve sections that are relatively slidable with respect to one another. The column uses camming guide rails in combination with cam followers located on the sleeve sections to provide for a column that is sturdy, compact, and may support a sufficiently heavy patient. One or more linear actuators provide for extension and retraction of the column.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to medical examination tables and, more specifically, to adjustable columns for examination tables.  
         [0002]     Adjustable tables have been previously used in the medical fields. Generally, the focus of prior table adjustment has been for angular or rotational displacement of the table bed. That is, the table base remains stationary while mechanical or hydraulic means tilt or angle the bed in other directions. Though these designs assist an examiner in repositioning a patient for different procedures, they do not allow for vertical mobility of the table. For instance, if a patient were to be moved from a wheelchair or a low resting gurney, such table would still need the patient to be lifted onto the table.  
         [0003]     Previous inventions have contemplated adjustable bases. For instance, Schnelle et al. (U.S. Pat. No. 4,589,642), discloses an adjustable base that uses hydraulic cylinders moving in opposite directions to adjust the base height. However, the hydraulic operating unit is mounted on the top of the cylinders, which increases the minimum height the cylinder may attain. Likewise, the placement of the unit provides for a louder operating unit than desired. Also, though compact, the base does not provide for the easiest access to all of the parts, if such parts require servicing. Thus, a compact, quiet, easily accessible base is contemplated.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides an adjustable column for an examination table that is compact, efficient, and may be easily serviced if necessary. The column is designed to minimize the space needed for the column while still providing sufficient, sturdy support for a patient resting upon the examination table. Also, the column is designed so that the column height is adaptable over a wider range of heights than possible with the prior art. Likewise, the minimum height of the column is less than previous minimum heights attainable by similar examination tables of the prior art.  
         [0005]     The column consists generally of three sleeve sections or members that are telescopingly related to one another. The first sleeve section is secured to the base of the table, with the second sleeve section slidingly connected to the first sleeve section. A third sleeve section is slidingly connected to the second sleeve section and attached to the table bed.  
         [0006]     The three sleeve sections are designed so that each successive sleeve section nestingly fits around the previous sleeve section. Preferably, the first sleeve section has the smallest perimeter and the following sleeve sections have increasingly larger perimeters. The sleeve sections form a generally rectangular shape, with the sleeve sections formed by joining together two overlapping U-shaped sleeve sections of material.  
         [0007]     The sleeve sections are moved upward and downward by a pair of actuators, one located within the column sleeve sections and one located on the outside of the column sleeve sections. The inside actuator controls movement of the second sleeve section with respect to the first sleeve section. The outside actuator is attached at the bottom of the second sleeve section and the top of the third sleeve section so that the two sleeve sections may be moved simultaneously. The column may be designed having both the actuators located inside of the column, or both actuators may be located outside of the column.  
         [0008]     The sleeve sections of the column move relative to one another by guide rails and cam followers located on opposing sides of the column sleeve sections. The guide rails are longitudinally extending with a pair of oppositely disposed parallel guide surfaces. The guide rails are located between the first and second sleeve sections, and the second and third sleeve sections, with accompanying cam followers for each rail. The rails are mounted on the outside and inside of the second sleeve section, and the cam followers have an eccentric diameter for adjustment against the rails. The cam followers are oppositely disposed and spaced apart and are in guiding contact with an oppositely respective disposed parallel guide surface of the guide rail. The design allows for smooth upward and downward movement of the column as well as support for heavier patients without diminishing the effectiveness of the column.  
         [0009]     The design of the column allows easy access for maintenance, as well. Because the rail and cam followers inside the columns may be easily accessed through the top of the column without complicated disassembly of the column, a person may service the column in a quick and efficient manner. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of an examination table with the base in an extended position employing the present invention.  
         [0011]      FIG. 2  is a perspective view of an examination table with the base in a retracted position employing the present invention.  
         [0012]      FIG. 3  is a perspective view of the present invention in an extended position.  
         [0013]      FIG. 4  is an overhead view of the present invention.  
         [0014]      FIG. 5  is an overhead view of the present invention containing an actuator inside of the present invention.  
         [0015]      FIG. 6  is a sleeve sectional perspective side view of the present invention showing the guide means of the present invention.  
         [0016]      FIG. 7  is a close-up view of the guide means of the present invention.  
         [0017]      FIG. 8  is a close-up sleeve sectional view of the body of the present invention.  
         [0018]      FIG. 9  is a close-up perspective view of an actuator used in the present invention.  
         [0019]      FIG. 10  is a cut-away perspective view of the view shown in  FIG. 5 .  
         [0020]      FIG. 11  is a perspective view of an alternate column. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.  
         [0022]      FIG. 1  is a perspective view of an examination table  10 . The table generally comprises a support bracket  12 , a support column  14 , and a base  16 . The focus of the present invention is on the support column  14  and the adjustable nature of the column  14 . The column  14  generally comprises three sleeve sections or members: a first or lower sleeve section  18 , a second or middle sleeve section  20 , and a third or upper sleeve section  22 . The first sleeve section  18  is attached to the base  16 , the second sleeve section  20  is attached to the first sleeve section  18  and the third sleeve section  22 , and the third sleeve section  22  is attached to the support bracket  12  of the table  10 . The third sleeve section  22  may be attached to the support bracket  12  in any sufficient manner that will secure the column  14  to the support bracket  12 .  
         [0023]      FIG. 2  shows the table  10  with support column  14  in a retracted position. The third sleeve section  22  slides nestingly downward over the second sleeve section  20  (not shown), which slides nestingly downward over the first sleeve section  18  (not shown). The height of the column  14  may be adjusted significantly. As shown in  FIG. 1 , the table is extended to a height of about 42 inches, which is the typical or normal height of an examination table. The present invention allows the column  14  to be compressed to a minimum height less than 20 inches, or approximately 19 inches, which facilitates transportation and movement of patients who may need to be moved from a wheelchair or other similarly shorter object. Previous designed prior art columns have been known to have a lowest height of only 22 inches, and a column range of only 18 inches. The three sleeve sections are arranged so that the diameters of the sleeve sections decrease from the third sleeve section  22  to the first sleeve section  18 , thereby preventing a sleeve section from interfering with the movement of an adjacent sleeve section. Similarly, the sleeve sections may be designed so that the diameters increase as oppose to decrease from the third sleeve section  22  to the first sleeve section  18 . Likewise it should be understood that the invention is adaptable for use with more or fewer sleeve sections, depending on personal needs or preferences.  
         [0024]     Referring to  FIG. 3 , a perspective view of the support column  14  is shown without an outer casing. A longitudinally extending guide rail or camming guide rail  24  is attached to each of the surfaces  26  of the second sleeve section  20 , preferably axially aligned with the center of each of the surfaces  26 . The guide rail  24  is securely attached to the second sleeve section  20  and comprises guide means for movement of the column  14 . The guide rail  24  may be attached with any known means, such as nuts and bolts, rivets, or screws, that will not interfere with the function of the guide rail  24 . Preferably, each side of the second sleeve section  20  has a rail  24  attached to each side, centrally aligned on each side. Such an arrangement provides for smooth movement of the column  14  upwards and downwards and contributes to the stability of the column  14 .  
         [0025]      FIG. 4  shows an overhead view of the column  14 . The first sleeve section  18  is shown nesting evenly within the second sleeve section  20 , which nests evenly within the third section  22 . As mentioned above, the rails  24  are located on the outside center of the surfaces or walls  26  of the second sleeve section  20 . Also, a second set of rails  28  are located on the inside center of the walls  26 . The outside rails  24  and the inside rails  28  are manufactured and designed in the same way and perform similar guide functions. The outside rails  28  guide the movement of the second sleeve section  20  with respect to the third sleeve section  22 , and the inside rails  28  guide the movement of the second sleeve section  20  with respect to the first sleeve section  18 . To further assist the guide rails  24  and  28  in guiding the sleeve sections, a plurality of cam followers  30  are situated along the rails  24  and  28 . The interaction of the guide rails  24  and  28  and the cam followers  30  allow the sections to be spaced apart in a generally uniform fashion. The actual function and movement of the cam followers  30  will be described in more detail with respect to  FIGS. 6 and 8 .  
         [0026]     Still referring to  FIG. 4 , the first sleeve section  18  comprises a plurality of inwardly facing lips  32  corresponding to each side of the first sleeve section  18 . The lips  32  allow the first sleeve section  18  to be secured to a bracket  17 , which will in turn be secured to the base  16  (not shown). Any suitable means, such as screws, bolts, rivets, or other securing devices, may be used to secure the first sleeve section  18  to the bracket  17  and, also, to the base  16 . Likewise, instead of lips  32 , other devices, such as braces or struts, may aid in attaching the column  14  to the base. The first sleeve section  18  and the base  16  could also be connected mechanically, by welding, with an adhesive, or with any other suitable means.  
         [0027]      FIG. 5  shows the same overhead view as shown in  FIG. 4  except with the inclusion of an actuator  34  within the column  14  and a second actuator  35  is attached to the outside of the column  14 . The actuator  34  is secured to the bracket  17  by any fastening means as described above regarding the first sleeve section  18 . The actuator  34  is arranged within the column  14  in such a manner to minimize the amount of overall space and area needed for the column  14 . Also, the actuator  34  is positioned so that it will not interfere with the movement of the sleeve sections relative to one another.  
         [0028]     Referring to  FIG. 10 , a perspective cut-away sectional view of the actuator  34  and the column  14  is shown. The bracket  17  is secured to the lips  32  of the first sleeve section  18 , which is then secured to the base  16 . A second set of fasteners  19  is used to secure the first sleeve section  18  to the base  16  without any connection to the actuator  34  or the bracket  17 . It should be noted that the actuator  34  may be secured to the base  16  with the same fasteners that secure the first sleeve section  18  to the base  16 , as described above with respect to  FIG. 4 , thereby minimizing the number of fasteners needed to secure the column  14  to the base  16 . However, such an arrangement would lead to an unstable column  14  if the actuator  34  were to be removed from the column  14  for any purpose.  
         [0029]      FIG. 6  shows a side view of the column  14 . The guide rail  24  is shown centrally located on the second sleeve section  20  with the cam followers  30  in contact with the guide rail  24 . The cam followers  30  are shown in phantom as they are located on the inside surface of the third sleeve section  22 . The guide rail  24  longitudinally extends the length of the surface  26  of the second sleeve section  20 . The guide rail  24  has a pair of oppositely disposed parallel guide surface  44 , which provide an area for the cam followers  30  to be in guiding contact with the guide rail  24 . The cam followers  30  are preferably placed parallel from one another across the guide rail  24 , with one of the cam followers  30  each in contact with one of the guide surfaces  44 . A second set of the cam followers  30  are spaced laterally from the first cam followers  30 . Such an arrangement provides stability and strength for the column to support heavier patients, including patients up to at least 450 pounds (204 kilograms), even if the patient is located in a cantilevered position on the table. Such a cantilevered position may take place if a patient were to kneel on an end of the table  10 . The cam followers  30  are also arranged to rest only on the rails  24  or  28  and not the sleeve sections  18 ,  20 , or  22  of the column (see  FIGS. 4 and 5 ), thereby lessening the stress of the parts of the column  14  as it moves upwardly and downwardly. The actuator  35  is attached to the bottom of the second sleeve section  20 .  
         [0030]      FIG. 7  shows the cam follower  30  in more detail. The cam follower  30  is comprised of an inner rotating shaft  40  and an outer rolling sleeve section  42 . The inner rotating shaft  40  will be secured to the column sleeve sections  18  and  22  (see  FIGS. 4 and 5 ) by a threaded section  43 , while the outer rolling sleeve section  42  will make contact with the rails  24  and  28  (See  FIGS. 4, 5 , and  6 ). The inner rotating shaft  40  is eccentric with the outer rolling sleeve section  42  to allow for alignment adjustment of the cam follower  30  against the rails  24  and  28 . The outer rolling sleeve section  42  preferably, but not essentially, has a slight crown (˜12 inch radius) to further align the cam followers  30  with the rails  24  and  28 . While the threaded section  43  is used to attach the cam followers  30  to the column  14 , any suitable attaching means may be used, providing the outer section  42  is still allowed to rotate. When the sleeve sections  18 ,  20 , and  22  are moved relative to one another, the eccentric design of the cam follower  30  allows the sections  18 ,  20 , and  22  to move in an axially aligned manner with one another. When traveling up and down the guide rails  24  and  28 , the cam follower  30  design will allow for slight side-to-side movement to keep the sections  18 ,  20 , and  22  essentially aligned.  
         [0031]     Now referring to  FIG. 8 , the design of the separate column sleeve sections  18 ,  20  and  22  is discussed. The three sleeve sections, though having different dimensions are designed in the same manner. The holes for the guide rails  24  and  28  and the cam followers  30  are not shown in this Figure. A large U-shaped portion  36  and a small U-shaped portion  38  are combined to form each of the respective sleeve sections. The two portions  36  and  38  are secured together with conventional fasteners, such as nuts and bolts, to form a generally rectangular shape. The sections  36  and  38  may also be combined by welding, adhesives, or other means that will allow the column  14  to keep its predetermined shape. Using different sized portions  36  and  38  prevents interference of the securing area to with the rails  24  and  28  and the cam followers  30  (see  FIGS. 4 and 5 ), and also makes it easier to accurately shape the sections.  
         [0032]     Likewise, the column  14  could be designed to have more or fewer sections to make the sleeve sections, for instance the U sections  36  and  38  divided each into two corner sections. The sleeve sections  18 ,  20 , and  22  should be interpreted broadly. Any nesting sections will fall within the scope of the sections described. Thus, the specific sections do not have to be of a closed polygonal shape, but may have an open side or open sides, providing that the specific section nests with the adjoining sleeve section or sections.  
         [0033]     As an example,  FIG. 11  shows a perspective view of a different embodiment of the first and second sleeve sections  18  and  20 . The first sleeve section  18  may be designed as a solid section with the second sleeve section  20  surrounding it as a C-shaped. The rail  28  and cam followers  30  (shown in phantom) would ride between the two sections  18  and  20  in a similar fashion as previously described. Even though the sections are not enclosed polygonal shapes, they would fall within the scope of this invention as forming nesting sleeve sections.  
         [0034]     A perspective view of the actuator  34  is shown in  FIG. 9 . The actuator  34  is a linear actuator of a standard design known in the field of invention. The actuator  34  is comprised of three general parts: a piston  46 , a piston housing  48 , and a motor  50 . The preferred embodiment employs two actuators  34  and  35 , one actuator  34  located within sleeve sections (see  FIG. 5 ), and one  35  located outside of the sleeve sections (see  FIG. 3 ). The inside actuator  34  and the outside actuators  35  are of the same design and perform the same general functions of raising and lowering the column  14 . The outside actuator is attached to the bottom of the second sleeve section  20  and the top of the third sleeve section  22  to allow both sections  20  and  22  to move at the same time. The inside actuator is attached to the bracket  17  at the same place where the first sleeve section  18  is attached to the bracket  17  (see  FIGS. 4 and 5 ). The inside actuator controls relative movement of the second sleeve section  20  to the first sleeve section  18 . In  FIG. 3 , a third actuator, shown in phantom, is not considered part of the invention.  
         [0035]     The column  14  will operate most efficiently if the rails  24  and  28  are aligned along the center of the surfaces  26  (see  FIG. 4 ) and preferably aligned with one another. The rails  24  and  28  are preferably made from a hardened to steel to prevent undue wear. Similarly, it is preferred that a rail and cam follower combination is present at each pair of facing surfaces, but the column will operate if such an arrangement is not present.  
         [0036]     The columns  14  are shown to be rectangular in shape. However, the sleeve sections may be of any shape, provided that they having nesting surfaces so that the guide rails and the cam followers may interact. Also, the columns may not necessarily be of the same shape. For instance, a column may have an octagonal shape, while another may be rectangular, and the column would still fall within the scope of the invention.  
         [0037]     The guide rails  24  and  28  are shown as being attached or secured to the column  14  sections. The term secured should be interpreted broadly to encompass any arrangement that will hold the guide rails  24  and  28  relatively connected. For instance, the guide rails may be welded or adhered to the sections. Likewise, the guide rails may be integrally formed as a section of one of the sections, which would still fall within the definition of secured as used in the specification. Provided a guide rail is connected to one of the sections in any fashion, integrally or separately, it will fall within the definition of secured as used herein.  
         [0038]     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.