Abstract:
An expandable, self-adjusting core plug which will maintain a fit between core plug and an out-of-round web roll core. The present invention accomplishes this by providing a core plug with a number of individual, elongated beveled ribs and a corresponding beveled spindle, both of which cooperatively and axially adjust the thickness of the core plug to meet variations in the inner diameter of the core.

Description:
This application claims priority from provisional application Ser. No. 60/178,873, filed Jan. 29, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to core plugs insertable into a web roll core, and in particular, to an expandable core plug for improved gripping of such cores. 
     In manufacturing and other operations, a roll of material may need to be mounted onto or off a roll. In conventional web treatments where machines handle reels of paper, plastics, metal foils, textiles and other sheet material, the cores of these reels need to be mounted on the machines so that rotational drive can be selectively coupled to the cores to effect winding or unwinding of the web entrained on the cores. The cores carrying the webs are normally tubular components made from cardboard, metal or plastic material. To effect the rotational drive to a core, it is desirable to include a core plug in either end of the core. The core plugs engage and rotatably support the core. Once the core plugs are inserted into the core, the core plugs are mounted on a roll stand which fits into journals of the core plugs. 
     As stated above, the cores are usually made of heavy paper or cardboard in tubular form. Cores, being made of paper, cannot be held to a close internal diameter tolerance. The cores become “out-of-round” affecting the fit of the core plug into the core. The core and core plug become loose thereby causing the core and core plugs to bang against each other. The looseness of fit between core and core plug can cause significant local stresses in the core to the point that the core structure and core plugs are damaged. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the problem of prior art core plugs by providing an expandable, self-adjusting core plug which will maintain a fit between core plug and an out-of-round core. The present invention accomplishes this by providing a core plug with a number of individual, elongated beveled ribs and a corresponding beveled spindle, both of which cooperatively and axially adjust the thickness of the core plug to meet variations in the inner diameter of the core. 
     These together with other objects of the invention, along with various features of novelty which characterize the invention, are pointed out with particularity in this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an expandable core plug assembly without spindle. 
     FIG. 2 is a plan view of FIG. 1 from the proximal plate outer surface. 
     FIG. 3 is a side view of FIG.  1 . 
     FIG. 4 is a plan view of FIG. 1 from the distal plate outer surface. 
     FIG. 5 is a plan view along the line  5 — 5  of FIG. 6, showing the position of the rib against a distal plate. 
     FIG. 6 is a side elevational view of a rib. 
     FIG. 7 is a plan view along the line  7 — 7  of FIG. 6, showing the position of the rib against a distal plate. 
     FIG. 8 is a side elevational view of the spindle. 
     FIG. 9 is a proximal end view of the spindle. 
     FIG. 10 is a side cross-sectional view of the invention. 
     FIG. 11 is a distal end view of the invention. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring to the drawings in detail wherein like elements are indicated by like numerals, there is shown an expandable core plug assembly  1  constructed according to the principles of the present invention. In this embodiment of the invention the assembly  1  includes a round, flat, distal plate  10 , a round, flat, proximal plate  20 , six elongated spacers  30  interconnecting said plates  10 ,  20 , six elongated, beveled ribs  40 , generally parallel to and interspersed among said spacers  30  and also interconnecting said plates  10 ,  20 , and an elongated, beveled spindle  50  centrally positioned within said assembly  1  and protruding through said proximal plate  20  to said distal plate  10 , said spindle  50  being generally parallel to said spacers  30  and said ribs  40 . Said plates  10 ,  20  each having a plane parallel to the plane of the other plate. The proximal plate  20  has a diameter greater than the distal plate  10 . The assembly  1  has a generally cylindrical shape with the spacers  30  and ribs  40  acting as side walls extending from said distal plate  10  to said proximal plate  20 , said plates  10 ,  20  defining the longitudinal axis of the assembly, said spindle  50  forming the central longitudinal axis of the assembly  1 . The longitudinal axes of the spindle  50 , ribs  40  and spacers  30  are generally perpendicular to the planes of said plates  10 ,  20 . The assembly  1  is adapted to being inserted into a hollow web core  2 , distal plate  10  first, up to, but not including, said proximal plate  20 . The assembly ribs  40  engage the inner wall  3  of said web core  2 . 
     The distal plate  10  has an inner surface  11  and an opposite, outer surface  12 , said inner surface  11  facing the proximal plate  20 . The distal plate  10  has a round, central opening  13  formed therein, as well as six round spacer holes  14  formed equidistantly near to the distal plate periphery  16 . Interspaced between said spacer holes  14  are six oval shaped rib holes  15 , each oval hole  15  having a longitudinal axis coincident with a radial axis of the plate  10 . The central opening  13 , spacer holes  14  and rib holes  15  extend through both surfaces  11 ,  12 . 
     The proximal plate  20  has an inner surface  21  and an opposite, outer surface  22 , said inner surface  21  facing the distal plate  10 . The proximal plate  20  has a round, central opening  23  formed therein. The proximal plate  20  has six round equidistant spacer holes  24  formed about a circle midway between the central opening periphery  27  and the proximal plate periphery  26 . Interspaced between said spacer holes  14  are six oval shaped rib holes  25 , each oval hole  25  having a longitudinal axis coincident with a radial axis of the plate  20 . The central opening  23 , spacer holes  24  and rib holes  25  extend through both surfaces  21 ,  22 . The proximal plate  20  also has eight round handle holes  28  formed equidistantly near to the proximal plate periphery  26 . Each of the handle holes  28  is adapted to receive a removable pin handle  9 . 
     The distal and proximal plates  10 ,  20  are interconnected by six spacers  30 . Each spacer  30  has a slim, cylindrical shape terminating at each end  31  in a round peg  32 . Each spacer end  31  abuts the inner surface  11 ,  21  of each plate  10 ,  20 . The spacer end pegs  31  are each inserted into and fastened within a plate spacer hole  14 ,  24 . The spacers  30  determine the length of the core plug assembly  1  and form the basic cylindrical shape of the assembly  1 . 
     As stated above, six, elongated beveled ribs  40  are interspersed among the spacers  30 . Each rib  40  has a distal end  41  and a proximal end  42 , each said end  41 ,  42  terminating in an oval plug  43 , and said ends  41 ,  42  defining the longitudinal axis of each rib  40 . Each rib distal end  41  abuts the distal plate inner surface  11 . Each rib proximal end  42  abuts the proximal plate inner surface  21 . Each rib oval plug  43  is inserted into a plate rib hole  15 ,  25 , each said rib oval plug  43  having a longitudinal axis coincident with a radial axis of the plates  10 ,  20 . Each plate rib hole  15 ,  25  has a longitudinal axis 60 to 80 thousands of an inch greater than the longitudinal axis of a rib oval plug  43 , thereby permitting some movement of each rib  40  outward from the assembly central longitudinal axis along a assembly radial axis. Each plate rib hole  15 ,  25  has a lateral axis 20 to 30 thousands of an inch greater than the longitudinal axis of a rib oval plug  43 , thereby permitting some twisting movement of each rib  40 . 
     Each rib  40  has a generally rectangular cross section and has an outside surface  44 , an opposite inside surface  45 , and two connecting side surfaces  46 . The rib inside surface  45  faces the assembly, central longitudinal axis. The rib outside surface  44  and side surfaces  46  are smooth and flat. Each rib outside surface  44  is positioned radially further from the assembly central longitudinal axis than each spacer  30 , and has a radius formed with the assembly central longitudinal axis greater than the radius of the distal plate  10 , each said rib outside surface  44  being adapted to engage a web core inner wall  3 . 
     Each rib inside surface  45  is beveled along its longitudinal axis. Beginning at the rib proximal end and moving longitudinally toward the distal end, the bevel arrangement is as follows. The plane of the first ten percent of the rib inside surface  45 , up to transverse line A, is parallel with the assembly central axis. The plane of next twenty-five percent of the rib inside surface  45 , up to transverse line B, is beveled toward the assembly central axis at a selected angle preferably between five and ten degrees. The plane of the next thirty percent of the rib inside surface  45 , up to transverse line C, is parallel with the assembly central axis. The plane of next twenty-five percent of the rib inside surface  45 , up to transverse line D, is beveled toward the assembly central axis at a selected angle preferably between five and ten degrees. The plane of the remaining ten percent of the rib inside surface  45 , up to the distal plate inner surface  11 , is parallel with the assembly central axis. 
     The present invention further includes an elongated, beveled spindle  50  having a distal end  51  and a proximal end  52 , said spindle ends  51 ,  52  defining the longitudinal axis of the spindle  50 . The spindle  50  is round along its length and is centrally positioned within said assembly  1 , protruding through said proximal plate central opening  23  to and through said distal plate central opening  13 , said spindle distal end  51  protruding through said distal end central opening  13 . The spindle longitudinal axis is generally parallel to the longitudinal axis of the spacers  30  and the ribs  40 . 
     The spindle  50  may be longitudinally divided into two portions, an internal portion  53  and an external portion  54 . The spindle external portion  54  is defined by the spindle proximal end  52  and a ring  55  formed about the spindle surface  56  at an approximate spindle longitudinal midpoint. The spindle internal portion  53  is defined by the spindle distal end  51  back to, but not including, the ring  55 . The spindle  50  is positioned within the assembly  1  so that the spindle internal portion  53  begins at the proximal plate central opening  23  extending through the distal plate central opening  13 . The surface  56  of the spindle internal portion  53  is longitudinally and radially beveled to correspond to the rib inside surface  45  beveled contours. The spindle ring  55  has a diameter greater than the diameter of the proximal plate central opening  23 , whereby the proximal plate central opening periphery  27  acts as a stop against the spindle ring  55  when the spindle is inserted into the assembly  1 . 
     It is understood that the above-described embodiment is merely illustrative of the application. Other embodiments may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof. The number of ribs  40  and spacers  30  in the invention may be varied. The number of rib and spindle bevels as well as angles of bevels may be varied. The size of the plate rib holes  15 ,  25  relative to the rib plugs  43  may be varied. The shape of the plate rib holes  15 ,  25  and rib plugs  43  may be varied, e.g., round, square, etc.