Abstract:
An adjustable bearing foot assembly for installation in a base plate, for example a base plate of a crane sub-assembly, including a threaded nut comprising an inner thread; a bearing foot having an outer thread; and a securing element with which the bearing foot can be fixed, rotationally secure, in the threaded nut.

Description:
FIELD 
       [0001]    The present application relates to support mechanisms for crane sub-assemblies. 
       BACKGROUND 
       [0002]    Presently, crane sub-assemblies such as mobile crane counterweight base plates are placed on supports prepared on an undercarriage of the mobile crane. By means of multiple abutments, it is elaborately tried to align the base plates in a position, which allows simple placement of the counterweight plates on the base plate. The multiple abutments are fixedly connected to the undercarriage and cannot be adjusted, for example upon change of the base plate. 
       SUMMARY 
       [0003]    An embodiment of an adjustable bearing foot assembly for installation in a base plate includes a threaded nut comprising an inner thread, a bearing foot comprising an outer thread, and a securing element with which the bearing foot can be fixed, rotationally secure, in the threaded nut. 
         [0004]    In another embodiment an adjustable footing support system for crane sub-assemblies includes a base plate with a bore, a threaded nut adapted to be secured in the bore, the threaded nut comprising an inner thread, a bearing foot comprising an outer thread, and a securing element with which the bearing foot can be fixed, rotationally secure, in the threaded nut. 
         [0005]    In another embodiment an adjustable footing support system for crane sub-assemblies includes a base plate having a first bore disposed therein and an nut configured to be secured within the first bore, the nut having a first face, a second face spaced apart from the first face, and a second bore with a first inner thread and a first central axis. The adjustable footing support system further includes a bearing foot having a second central axis aligned coaxial the first central axis, a first end and a second end spaced apart from the first end, and a first outer thread between the first end and the second end, the first outer thread intermeshed with the first inner thread of the nut, and a securing element configured to selectively fix a rotation of the bearing foot with respect to the nut. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    To further clarify the above and other advantages and features of the one or more present inventions, reference to specific embodiments thereof are illustrated in the appended drawings. The drawings depict only typical embodiments and are therefore not to be considered limiting. One or more embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0007]      FIG. 1  is a perspective view of a section of a base plate with three bearing foot assemblies. 
           [0008]      FIG. 2  is a perspective view of an individual bearing foot assembly with a securing element as depicted by circle A of  FIG. 1 . 
           [0009]      FIG. 3  is sectional view of an individual bearing foot assembly as depicted by circle B of  FIG. 1 . 
       
    
    
       [0010]    The drawings are not necessarily to scale. 
       DETAILED DESCRIPTION 
       [0011]    The present invention will now be further described. In the following passages, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. 
         [0012]    Embodiments of the invention are directed to an adjustable footing support for crane sub-assemblies, such as a counterweight base plate. While the embodiments will be described in connection with a counterweight base plate, it will be understood that the embodiments are suitable other crane sub-assemblies. 
         [0013]      FIG. 1  illustrates a portion of an adjustable footing support system  100  having a base plate  1  and three bearing feet  3 . The base plate  1  includes other bores  101 , unrelated to the invention, and therefore not explained in more detail. While  FIG. 1  shows only a portion of the base plate  1  with three bearing feet  3 , it will be understood that more or less than three bearing feet  3  are possible. The base plate  1  can have any number of bores  8  for the reception of nuts  2 . A nut  2  does not have to be seated in every one of the bores  8  and a bearing foot  3  does not have to be threaded into each nut  2 . For example, bore  102  and bore  103  do not have bearing feet  3  or nuts  2  disposed therein. 
         [0014]    The bores  8  may be formed by a process that removes material such as machining, drilling, milling, etc., or the bores  8  may be formed at the time the base plate  1  is made, such as a casting having the bores  8  present in the mold. The bores  8  of  FIG. 1  are through bores that extend from a top face  5  of the base place to a lower face (not shown). In other embodiments, the bores  8  may be blind bores formed in the lower face and not extending to the top face  5 . In still other embodiments, the bores  8  may have varying diameters and features such as countersinks. 
         [0015]    A nut  2  having a nut bore with an inner thread  21  is secured within each of the bores  8 . In other embodiments, a subset of the bores  8  may have nuts  2  secured therein. The nuts  2  may be secured within the baseplate  1  by way of a press fit, welding, gluing, bonding, brazing, or any other type of securing technique as known in the art. Preferably, the nuts  2  are welded into the base plate  1  on one or both front sides. In embodiments where the nuts  2  are press-fitted in the base plate  1 , they may be subjected to a cold treatment before press-fitting, such that they expand by warming to ambient temperature in the fitted state, thereby increasing the pressing force in the bore  8 . In some embodiments, the nut  2  has an outer thread and the bore  8  has an inner thread. In such embodiments the nut  2  is threaded into the bore  8  and secured in place. In some embodiments the nut may overhang the bore such that a portion of the nut extends beyond the bore. 
         [0016]    A bearing foot  3  having an outer thread  31  sized and shaped to thread into the nut bore is threaded into the inner thread  21 . At this time, the bearing foot  3  is free to rotate within the nut  2  and the bearing foot&#39;s  3  axial position is constrained by the mating of the inner thread  21  and the outer thread  31 . 
         [0017]    A securing element  4  constrains the rotational movement of the bearing foot  3  relative to the nut  2 . When in place, the securing element  4  prevents the bearing foot  3  from being threaded into or out of the nut  2 . In combination with the axial constraint provided by the mating threads  21 ,  31 , the bearing foot  3  is effectively secured in place. When the securing element  4  is removed, the bearing foot  3  can again be threaded into or out of the nut  2 . 
         [0018]    For adjusting or aligning the base plate  1 , it can be placed on a supporting surface and be aligned by adjustment of the bearing feet  3  to compensate for any unevenness of the supporting surface and manufacturing tolerances of the base plate  1 . Each of the bearing feet  3  can be individually threaded into the nut  2  or be threaded through the nut  2 . The length of a portion of the bearing foot  3  protruding beyond the bottom face of the base plate  1  is varied by threading the bearing foot  3  into the nut  2 , and the position of the base plate  1  with respect to the supporting surface is correspondingly adjusted. By means of the bearing feet  3 , the base plate  1  can thus be aligned. 
         [0019]    Once each of the bearing feet  3  are adjusted, they are then be locked in place with the securing element  4 , preventing further movement of the bearing feet  3 . Thus the positions of the bearing feet  3  are prevented from changing with the time by vibration or other disturbance. The base plate  1  does not have to be continuously readjusted, as the bearing feet  3  are secured in the nuts  2  with securing elements  4  with the base plate  1  aligned. 
         [0020]      FIG. 2  is a close up view of the bearing foot  3  and the securing element  4  of  FIG. 1  secured to the baseplate  1 . The securing element  4  is a disk having an opening  42  sized and shaped to complement a cross section of the bearing foot  3  extending from the top of the nut  2 . The securing element  4  is placed adjacent the nut  2  such that the bearing foot  3  extends through the securing element  4 . The bearing foot  3  and the opening  42  together couple the rotation of the securing element  4  and the bearing foot  3 . 
         [0021]    The securing element  4  has at least one through bore  41 , preferably a plurality of through bores  41  arranged annularly about the axis of the securing element  4 . The nut  2  has at least one blind bore  22  at the same radial distance as the through bores  41 . The blind bore  22  is threaded and sized to receive a screw  9 . The screw  9  is inserted through the through bore  41  and threaded into the blind bore  41 . With the screw  9  threaded into the blind bore  41 , the securing element  41  is constrained from moving relative to the nut  2 . More than one blind bore  22  may be present in the nut  2  and preferably the nut  2  has a plurality of blind bores  22  arranged annularly about the axis of the nut  2 . The spacing of the through-bores  41  determines how finely the bearing foot  3  can be adjusted. 
         [0022]    Due to the cross section of the bearing foot  3  protruding beyond the securing element  4  and the shape of the opening through with the bearing foot  3  extends, the bearing foot  3  can no longer be rotated relative to the nut  2 . 
         [0023]    In the embodiment of  FIG. 2 , the nut  2  has three blind bores  22  underneath the securing mechanism  4  at an angular distance of 120° from one another. Accordingly, the bearing foot  3  can only be secured in a position in which the through-bore  41  aligns with a blind bore  22 . 
         [0024]    Preferably, three blind bores  22  are equidistantly provided on the front side of the nut  2  at an angular distance of 120° between the blind bores  22 . However, four through bores  41  with four corresponding blind bores  22  or six through bores  41  with six corresponding blind bores  22  can also be provided with angular distances of 90° and 60°, respectively. Preferably, the securing element  4  has numerous through bores  41  that align with the blind bores  22  in the front side of the nut  2  in each position of the bearing foot  3  and the bearing foot  3  can be connected to the nut  2  in numerous positions. 
         [0025]    That is, the more through-bores  41  present in the securing element  4 , the finer the bearing foot assembly  10  can be adjusted. However, the spacing of the through-bores  41  cannot be selected arbitrarily small, since there would be the risk that the material between the individual through-bores  41  would yield upon loading. However, the number of the through-bores  41  can be increased if the outer radius of the securing element  4  is increased. If the nut  2  does not protrude beyond the top face  5  of the base plate  1 , the securing element  4  can also have an outer diameter, which is larger than an outer diameter of the nut  2 . Thus, in another embodiment, the securing element  4  is attached directly to the base plate  1  using through bores  7  annularly arranged on the base plate  1 . The larger diameter of the annular arrangement could allow a finer adjustment of the bearing foot  3 . 
         [0026]    In this case, the blind bores  7 , in which the securing element  4  is retained by screws  9  for securing the bearing foot  3 , are not formed on the front side of the nut  2 , but in the top face  5  of the base plate  1 . This prevents the bearing foot  3  from being able to be rotated in the nut  2  if the securing element  4  is threaded onto the base plate  1 . A load of the securing element  4  in the rotating direction of the bearing foot  3  is not transmitted to the nut  2  in this embodiment, but is instead received by the base plate  1 . 
         [0027]    In  FIG. 3 , a cross-section of a footing support  10  is shown. Preferably, the bearing foot  3  is longer than the nut  2 . A threaded portion  33  of the bearing foot  3  can correspond to the overall length of the thread of the nut  2 . The bearing foot  3  has a first unthreaded portion  32  above the threaded portion  33  and a second unthreaded portion  34  below the threaded portion  33 . Thus, the first unthreaded portion  32  and the second unthreaded portion  34  protrude from the top and bottom of the base plate  1 , respectively, with the outer thread  31  of the bearing foot  3  completely threaded into the inner thread  21  of the nut  2 . 
         [0028]    The bearing foot  3  can be threaded by hand, or through the use of a tool. The first unthreaded portion  32  has a cross section that is complementary to a tool. The first unthreaded portion  32  of the bearing foot of  FIG. 3  has a cross section that is generally square in shape and is complementary to a tool having a squared recess sized and shaped to match the cross section, such as a square spanner. In other embodiments the cross section may have a different shape such as a triangle, a rectangle, a polygon, a star, etc. Shapes allowing the use of standard tools are therein preferred. 
         [0029]    The function of the footing support system  100  can be simply explained. The base plate  1  prepared with the nuts  2  is applied in the field. From the top, the bearing foot  3  can be screwed into the nut  2  until they are flush with the bottom  6  of the base plate, or with nut  2  protruding beyond the bottom  6 , flush with the end of the nut  2 . Now, the base plate  1  can be adjusted by further screwing the bearing feet  3  into the nut  2  by means of a tool (not shown), thereby lifting the base plate  1 . If the base plate  1  is in the desired position, each of the bearing feet  3  is secured by means of a securing element  4  in its adjusted position, wherein very small corrections of individual bearing foot positions can be required to exactly position the through-bores  41  above the threaded bores  22 , in order that the screws  9  can be screwed into the threads of the threaded bores  22 . Now, the base plate  1  rests on the portions  34  of the bearing feet  3 .