Abstract:
A method of constructing a metal tubular frame structure utilizing a first tubular member and a second tubular member is provided. The method involves utilizing at least one opening in the first tubular member and at least one end tab on the second tubular member that together produce a keyed tubular joint when the second tubular member engages the first tubular member with the tab inserted within the opening. Keyed tubular insert-type joints, keyed tubular miter-type joints and keyed tubular flush-type joints can be formed.

Description:
TECHNICAL FIELD 
       [0001]    This application relates generally to tubular frame structures for use in bakery processing equipment and, more specifically, to a method of constructing a tubular frame structure that utilizes self-fixturing of interconnecting tubular components. 
       BACKGROUND 
       [0002]    Commercial dough handling apparatus such as horizontal dough mixers, rotary dough feeders, spiral dough feeders, dough conveyors and dough dividers commonly use frame structures. Construction of such frame structures can be time-consuming and expensive. 
         [0003]    It would be desirable to provide a frame system and method that facilitates the construction process as well as an effective frame configuration, providing stable, strong welded joints between interconnected tubular members. 
       SUMMARY 
       [0004]    In one aspect, a method of constructing a metal tubular frame structure utilizing a first tubular member and a second tubular member is provided. The method involves utilizing at least one opening in the first tubular member and at least one end tab on the second tubular member that together produce a keyed tubular joint when the second tubular member engages the first tubular member with the tab inserted within the opening. 
         [0005]    In another aspect, a method of constructing a metal tubular frame structure utilizing a first tubular member and a second tubular member is provided, where a transverse cross-sectional size of the first tubular member is larger than a transverse cross-sectional size of the second tubular member. The method involves utilizing a set of openings in the first tubular member and a set of end tabs in the second tubular member that together produce a keyed tubular insert joint when the second tubular member is inserted into the first tubular member. 
         [0006]    In one implementation of the foregoing aspect, the method includes: the first tubular member including a first opening in a sidewall of the first tubular member, the first opening shaped and sized to substantially match an outer perimeter shape of a sidewall of the second tubular member; the first tubular member including at least second and third openings in the sidewall of the first tubular member in respective positions that are spaced from the first opening, but that are aligned along a length of the first tubular member with the first opening; the second tubular member including at least first and second sidewall extension tabs in a first end of the second tubular member, the first and second sidewall extension tabs sized and shaped to substantially match the size and shape of the second and third openings; inserting the first end of the second tubular member into the first opening of the first tubular member; aligning the first sidewall extension tab of the second tubular member with the second opening of the first tubular member, and aligning the second sidewall extension tab of the second tubular member with the third opening of the second tubular member; moving the first end of the second tubular member further into the first opening of the first tubular member so that the first sidewall extension tab moves into the second opening and the second sidewall extension tab moves into the third opening, such that rotation of the second tubular member relative to the first tubular member is substantially inhibited by interaction of the first sidewall extension tab and the second opening and the second sidewall extension tab and the third opening. 
         [0007]    In one implementation of the method of the preceding paragraph, the method further involves: welding the first sidewall extension tab of the second tubular member to the sidewall of the first tubular member; (ii) welding the second sidewall extension tab of the second tubular member to the sidewall of the first tubular member; and (iii) welding the sidewall of the second tubular member to the sidewall of the first tubular member along a perimeter of the first opening. 
         [0008]    In a further aspect, a metal tubular frame structure includes a first tubular member and a second tubular member. The first tubular member and second tubular member are joined together, with at least one opening of the first tubular member and at least one end tab of the second tubular member engaged to define a keyed tubular joint. 
         [0009]    In another aspect, a metal tubular frame structure includes a first tubular member and a second tubular member, where a transverse cross-sectional size of the first tubular member is larger than a transverse cross-sectional size of the second tubular member. The first tubular member and second tubular member are joined together, with a set of openings of the first tubular member and a set of end tabs of the second tubular member engaged to define a keyed tubular insert joint. 
         [0010]    In one implementation of the foregoing aspect, the first tubular member has a first sidewall opening shaped and sized to substantially match an outer perimeter shape of a sidewall of the second tubular member, and second and third sidewall openings in respective positions that are spaced from the first opening but aligned with the first opening along a length of the first tubular member. The second tubular member has a first end with first and second sidewall extension tabs formed therein, where the first and second sidewall extension tabs are sized and shaped to substantially match the size and shape of the second and third openings respectively. The first end of the second tubular member is located within the first opening of the first tubular member, with the first sidewall extension tab located within the second opening and the second sidewall extension tab located within the third opening. 
         [0011]    In one implementation of the structure of the preceding paragraph, the joint is made permanent. In particular, the first sidewall extension tab is welded to the sidewall of the first tubular member to cover an exterior side of the second opening with weld material. The second sidewall extension tab is welded to the sidewall of the first tubular member to cover an exterior side of the third opening with weld material. The sidewall of the second tubular member is welded to the sidewall of the first tubular member to form a fillet weld along a perimeter of the first opening. 
         [0012]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of an exemplary tubular frame structure; 
           [0014]      FIG. 2  is a perspective view of one end of a tubular member; 
           [0015]      FIG. 3  is a top plan view of the end of the tubular member of  FIG. 2  joined to another tubular member; 
           [0016]      FIG. 4  is a partial side elevation of the other tubular of  FIG. 3  showing openings in the sidewall of such tubular member; 
           [0017]      FIG. 5  is a partial cross-section showing a joint embodiment in which sidewall extension tabs do not protrude; 
           [0018]      FIG. 6  is a side elevation of the end of a tubular member in an embodiment in which the end edges of the sidewall extension tabs are contoured in the lengthwise direction of the tubular member; 
           [0019]      FIG. 7  is a partial cross-section of one embodiment of a finished sidewall extension tab weld; 
           [0020]      FIG. 8  is a partial cross-section of another embodiment of a finished sidewall extension tab weld; 
           [0021]      FIGS. 9 ,  10 ,  10 A and  11  illustrate embodiments with three, four, four and one sidewall extension tab openings, respectively; and 
           [0022]      FIGS. 12 and 13  show both a keyed miter-type tubular joint and a keyed flush-type tubular joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Referring to  FIG. 1 , an exemplary dough mixer frame structure  10  is shown and is made up of a plurality of tubular members, including upright tubular members  12   a - 12   d,  lateral tubular members  14   a - 14   f  and lateral tubular members  16   a - 16   b.  Lateral tubular members  14   a - 14   c  extend between upright tubular members  12   a  and  12   b.  Lateral tubular members  14   d - 14   f  extend between upright tubular members  12   c  and  12   d.  Lateral tubular members  16   a  and  16   b  extend between lateral tubular members  14   a  and  14   d.  A keyed tubular joint is formed at each of the multiple tubular joint locations (e.g.,  18   a - 18   n ). In this case each keyed tubular joint is a keyed tubular insert joint in which one tubular member is smaller than another and has an end inserted within a sidewall opening of the larger tubular member as will be described further below, but it is contemplated that one or more of the joints could also be non-insertion type joints in which there is no opening that is large enough to receive the entire end of the mated tube as will also be described further below. Accordingly, it is recognized that the illustrated tubular frame configuration is one example only, and that the overall tubular frame configuration (e.g., number of interconnected tubular members, size of the members, configuration of the members and resulting frame structure etc.) could vary without departing from the scope or nature of the invention, which resides primarily in the configuration of each of the multiple keyed tubular insert joints and the method of manufacturing a frame structure using one or more of such joints. 
         [0024]    Referring now to  FIGS. 2-4 , one embodiment of such a keyed tubular insert joint is described with reference to exemplary tubular members  30  and  32 , where a transverse cross-sectional size of the tubular member  30  is larger than a transverse cross-sectional size of the tubular member  32 . In the case of the illustrated right circular cylinder type tubular members, the transverse cross-sectional size of each tubular member is defined by the area encompassed within a circle defined by the outer surface of tubular member in a plane that is perpendicular to a longitudinal axis of the tubular member. It is, however, recognized that other tubular member shapes could be used (e.g., square or other rectangular, oval etc.). The lengthwise axis  40  and  42  of each member  30  and  32  is shown in  FIGS. 4 and 2 . 
         [0025]    In order to produce the keyed tubular insert joint, an opening  34  is created (e.g., cut or otherwise formed) in the sidewall  36  of the larger tubular member  30 , where the opening  34  is shaped and sized to substantially match an outer perimeter shape of the sidewall  38  of the tubular member  30 , while at the same time being large enough to enable insertion of tubular member  32  within the opening  34  as will be described further below. Additional openings  44  and  46  are also created in the sidewall  36  of the larger tubular member  30 . As shown in  FIG. 4 , the openings  44  and  46  are located in respective positions that are circumferentially spaced from the opening  34 , but aligned along a length of the tubular member with the opening  34 . In  FIG. 4 , which is a side elevation of part of tubular member  30 , the openings  44  and  46  are visible through the opening  34  because they are located on the side of the tubular member directly opposite the side in which opening  34  is located. 
         [0026]    Sidewall extension tabs  48  and  50  are created at the end  52  of the tubular member  32 , where sidewall extension tabs  48  and  50  are sized and shaped to substantially match the size and shape of the openings  44  and  46  respectively, while at the same time being small enough to enable insertion of extension tabs  48  and  50  within the openings  44  and  46  as will be described further below. 
         [0027]    To assemble the keyed tubular insert joint, the end  52  of the tubular member  32  is inserted into the opening  34  of the tubular member  30 . The sidewall extension tabs  48  and  50  of the tubular member  32  are aligned with the openings  44  and  46  of the tubular member  30  (e.g., by rotation of the tubular member  32  as necessary). The end  52  of the tubular member  32  is moved further into the opening  34  of the tubular member  30  so that the sidewall extension tab  48  moves into one of the openings  44 ,  46  and the sidewall extension tab  50  moves into the other of the openings  44 ,  46 . When in this position, rotation of the tubular member  32  relative to the tubular member  30  is substantially inhibited by interaction of the sidewall extension tabs  48  and  50  and the openings  44  and  46 . Thus, the sidewall extension tabs  48  and  50  and openings  44  and  46  combine to form a keyed relationship between the end  52  of the tubular member  32  and the sidewall  38  of the tubular member  30 . As used herein, the term “keyed” relationship or “keyed” joint is meant to define a configuration in which the sidewall extension tabs of one tubular member (e.g., member  32 ) can only be inserted into the corresponding openings of the other tubular member (e.g., member  30 ) when the one tubular member has an appropriate rotational position (i.e., one specific rotational position, or in some cases one of several specific rotational positions) relative to the other tubular member so that the sidewall extension tabs align with the openings. This keyed relationship helps properly orient and locate the two tubular members relative to each other in a self-fixturing manner that facilitates the welding of the two tubular members together. Where the tubular members include additional sets of openings and/or extension tabs to make further connections to other tubular members, the self-fixturing also properly locates such additional openings and/or extension tabs. 
         [0028]    During the welding process, the sidewall extension tab  48  of the tubular member  32  is welded to the sidewall  36  of the tubular member  30  (e.g., at the perimeter of one of the openings  44 ,  46 ), the sidewall extension tab  50  of the tubular member  32  is welded to the sidewall  36  of the tubular member  30  (e.g., at the perimeter of the other of the openings  44 ,  46 ) and the sidewall  38  of the tubular member  32  is welded to the sidewall  36  of the tubular member  30  (e.g., along the outer surface of tubular member  32  at the perimeter of the opening  34 ). 
         [0029]    The sidewall extension tabs  48  and  50  are formed such that an end slot  54  formed in the sidewall  38  of the tubular member  32  in a region between the sidewall extension tabs defines a sidewall end edge portions  56  that is configured to match a shape of an internal surface  58  of the sidewall  36  of the tubular member  30  in a region between the openings  44  and  46 . The sidewall end edge portion  56  is moved into contact with the internal surface  58  as best seen in  FIG. 3 , and the abutment acts to limit the extent of the movement of tubular member  32  into the tubular member  30 . Two slots  54  and two end edge portions  56  are provided in the illustrated embodiment of  FIG. 3 , but the number could vary. 
         [0030]    As seen in  FIG. 3 , in one embodiment the sidewall extension tabs  48  and  50  are sized lengthwise so as to extend fully through and protrude from the openings  44  and  46 . However, in another embodiment the sidewall extension tabs are sized to move into, but not entirely through, the openings  44  and  46  (e.g., per the schematic cross-section of  FIG. 5 ). In furtherance of achieving this latter arrangement, when necessary, the end edge of each of the sidewall extension tabs  48  and  50  should be contoured in a lengthwise direction of the tubular member  32  to match varying position of the sidewall  36  of the tubular member  30  in each of the openings  44  and  46  respectively. One example of such lengthwise contouring of an end edge  60  of sidewall extension tab  50  is shown in the side elevation view of  FIG. 6 . 
         [0031]    In one implementation, the welding step for each of the sidewall extension tabs  48  and  50  completely fills an exterior side of both the openings  44  and  46  with weld material (e.g., either around the extension tabs  48  and  50  in the protruding embodiment of  FIG. 3 , or both around the extension tabs and over the end edges of the extension tabs in the non-protruding embodiment of  FIG. 5 ). The weld material (or weld material and sidewall extension tabs) can then be machined and/or polished to produce a smooth external surface, flush with an exterior surface of the sidewall  36  of the tubular member  30  per the embodiments reflected in  FIGS. 7 and 8 . A fillet weld may be produced between the sidewall  38  of the tubular member  32  and the sidewall  36  of the tubular member  30  along the perimeter of the opening  34  of the tubular member  30 . 
         [0032]    By the above process, a tubular frame structure (e.g.,  10  of  FIG. 1 ) of a dough handling apparatus can be produced, where a plurality of tubular members are interconnected together using a plurality of a keyed tubular insert joints of the type described above. In the tubular frame structure  10  of  FIG. 1 , non-tubular frame components are also provided, such as side plates  80  having openings  82  through which a dough mixer drive shaft assembly can extend, a curved top cover plate  84  and corner stabilizing brackets  86 . The side plates  80  include extension tabs on all sides that fit into slotted openings of the surrounding tubular frame members, and which are welded to the frame members at the perimeter of the slots. Likewise, the top cover plate includes slots into which upper extension tabs of the upright tubular members  12   a - 12   d  extend, with welds included. The frame feet  88   a - 88   d  may be connected to the upright tubular members using extension tabs on the lower ends of tubular members  12   a - 12   d  and openings sized to receive the extension tabs. 
         [0033]    While a keyed insert joint having a primary tube receiving opening  34  and two sidewall extension tab receiving openings  44  and  46  is described above, it is recognized that the number of sidewall extension tabs and corresponding sidewall extension tab receiving openings could be only one or could be greater than two (3 or 4 or 1 as shown in the embodiments of  FIGS. 9 ,  10  and  11 ). Moreover, as mentioned above, keyed tubular joints other than the insert type described above could be used. 
         [0034]    In this regard, reference is made to the miter-type keyed tubular joint  118   a  of  FIGS. 12 and 13 , which joins tubular members  102  and  104  of the same cross-sectional size. In this case, tubular member  102  includes sidewall extension tabs  106  and  108  and the end edge of the sidewall of tubular member  104  includes openings  110  and  112  in the form of recesses sized to receive the extension tabs  106  and  108 . The tabs and end edge openings operate to assist in holding the tubular members  102  and  104  in proper position during welding along the interface of the two mitered end edges of the respective member sidewalls. Again, while the illustrated embodiment includes two extension tabs and openings, the number could vary (e.g., one tab and one corresponding opening, or more than two tabs and more than two corresponding openings). 
         [0035]    An external flush-type keyed tubular joint  118   b  is also shown in  FIGS. 12 and 13 , which joins tubular members  104  and  105 . In the illustrated embodiment, tubular members  104  and  105  have the same cross-sectional size, but it is recognized that member  105  could have a smaller cross-sectional size than member  104  in this type of joint. In this joint  118   b,  tubular member  104  includes two openings  120  and  122  that receive two corresponding sidewall extension tabs  124  and  126  of tubular member  105 . The remainder of the end edge of the sidewall of tubular member  105  is shaped to seat flushly against an external surface  128  of the tubular member  104  when the end tabs  124  and  126  are inserted into the openings  120  and  122 . The joint is welded along the entire periphery  130  of the interface between the two members. Again, while the illustrated embodiment includes two extension tabs and openings, the number could vary (e.g., one tab and one corresponding opening, or more than two tabs and more than two corresponding openings). 
         [0036]    It is to be clearly understood that the above description is intended by way of illustration and example only, is not intended to be taken by way of limitation, and that other changes and modifications are possible. For example, while joints made up of tubular members having similar cross-sectional shape are primarily shown, similar joints between two tubular members of different cross-sectional shape could be formed as well. Moreover, while the illustrated joints having multiple engaged sidewall extension tabs and openings are generally shown with all tabs having the same size, all openings having the same size and with the tabs and openings in each case generally symmetrically positioned, it is recognized that (i) the tabs at the end of any give tubular member could be of different size, in which case the openings in a mated tubular member would preferably also be of different size to match a respective tab and (ii) the tabs and openings need not be arranged symmetrically. Further. while certain orientations of the sidewall openings are shown (e.g., such as the four sidewall tab extension receiving openings in  FIG. 10 ), the orientations could vary (e.g., the four sidewall tab extension receiving openings could be oriented as shown in  FIG. 14 )