Abstract:
A generally cylindrical expansible shaft includes an outer profile, and a generally cylindrical inner body having a longitudinal axis and at least one first coupling element. At least two semi-circular leaf elements may be movably coupled to the first coupling element of the inner body by means of at least one second coupling element. The leaf elements may together substantially form the outer profile of the generally cylindrical expansible shaft. At least one thrusting element may be operatively disposed between the leaf elements and the inner body to move the leaf elements radially outwards relative to the longitudinal axis to increase an outer diameter of the shaft when in a first configuration, and allow the leaf elements to move radially inwards relative to the longitudinal axis to decrease the outer diameter of the shaft when in a second configuration.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims benefit of priority of Provisional Application Serial No. 60/460,424 filed on Apr. 7, 2003. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    a. Field of Invention  
           [0003]    The invention relates generally to an expanding shaft, and, more particularly to an expanding shaft of the type which carries tubular supports on which strips of plastic, aluminum or paper films are wound or from which the strips are unwound.  
           [0004]    b. Description of Related Art  
           [0005]    During the manufacture of plastic, aluminum, paper or other sheet products, the sheet material is typically wound onto, or unwound from, a tubular core supported by a diametrically expansible shaft which is inserted into the core and expanded to grip the core frictionally. Such shafts are typically used when slitting a wide web of material into discrete widths and rewinding the material on the core. Conventional expansible roll core shafts typically employ a large number of relatively small, separate core-engaging elements expansible by a common internal air-expandable bladder, or by a plurality of individually controllable air-expandable bladders.  
           [0006]    Of known varieties of expansible shafts, as disclosed in U.S. Pat. No. 3,904,144, the disclosure of which is incorporated herein by reference, one type of shaft includes straight, parallel slots cut longitudinally in the periphery thereof. The slots include straight, separate, air-expandable, resilient bladders overlain by respective straight core-contacting elements which extend throughout the length of the shaft. One key drawback in such a shaft is in the overall ability to evenly load delicate cores to eliminate core distortion or damage, and the overall excessive weight of such shafts, which requires the implementation of special handling procedures and methods, and thus increases the overall manufacturing and operational costs for such shafts.  
           [0007]    Other known varieties of expansible shafts include the shaft designs disclosed in U.S. Pat. Nos. 5,597,134 and 5,746,386, the respective disclosures of which are incorporated herein by reference.  
           [0008]    The expansible shafts disclosed in the &#39;134 and &#39;386 patents disclose the use of mobile means mounted for radial movement within slots in the expanding shaft. Core stops are adjustably mounted for axial movement longitudinally of at least one of the mobile means to vary the spacing of the core stops longitudinally of the shaft as desired. Locking means is provided for locking the core stops in position axially of the mobile means and the shaft. With the arrangement as shown in the &#39;134 and &#39;386 patents, the longitudinal position of the core stops relative to the shaft can be adjusted while the shaft is mounted on a slitter-rewinder machine. However, due to the weight of the shaft and associated components, it generally takes a significant amount of labor and down time of the machine while such changes are made.  
           [0009]    While the expansible shaft disclosed in U.S. Pat. No. 6,196,494, which is owned by the assignee herein and the disclosure of which is incorporated herein by reference, provided significant improvement in the construction of an expansible shaft over the shafts disclosed in the &#39;134 and &#39;386 patents so as to permit the slit widths on a slitter-rewinder machine to be changed in a minimum amount of time, there remains a need for an improved expansible shaft having a reduced overall weight for further facilitating the overall manufacturing and operational costs thereof. There also remains a need for an improved expansible shaft which enables the application of higher torsional loads, and improved core loading for eliminating core distortion or damage, and an expansible shaft which is easier to assemble and disassemble, which includes a limited number of required components for ease of operability as well as for increased reliability and robustness of design, and which is economically feasible to manufacture.  
         SUMMARY OF INVENTION  
         [0010]    The invention solves the problems and overcomes the drawbacks and deficiencies of prior expansible shaft designs by providing an improved expansible shaft having exemplary objectives of a reduced overall weight for facilitating the overall manufacturing and operational costs thereof, a shaft which is capable of application of higher torsional loads, and includes improved core loading for eliminating core distortion or damage.  
           [0011]    The present invention achieves the aforementioned exemplary objectives by providing a generally cylindrical expansible shaft having an outer profile. The shaft includes a generally cylindrical inner body having a longitudinal axis and at least one first coupling element. At least two semi-circular leaf elements may be movably coupled to the first coupling element of the inner body by means of at least one second coupling element. The leaf elements may together substantially form the outer profile of the generally cylindrical expansible shaft. At least one thrusting element may be operatively disposed between the leaf elements and the inner body to move the leaf elements radially outwards relative to the longitudinal axis to increase an outer diameter of the shaft when in a first configuration, and allow the leaf elements to move radially inwards relative to the longitudinal axis to decrease the outer diameter of the shaft when in a second configuration.  
           [0012]    For the expansible shaft described above, the leaf elements may be resiliently biased radially inwards by means of a spring disposed between the inner body and the leaf elements. The spring may be either a leaf, wave or a coil spring. The first and second coupling elements may be complementary hooks. In a particular embodiment disclosed, the shaft may include two first and two second coupling elements, and three semi-circular leaf elements. The leaf elements may include a plurality of knurls on an outer surface for increasing friction of engagement with a core of a product to be gripped. The expansible shaft may further include an air journal removably coupled with the inner body and including an intake opening for permitting air to be supplied to the thrusting element for moving the leaf elements to the first configuration. The air journal may further include an exit opening for permitting air to be removed from the thrusting element for moving the leaf elements to the second configuration. The air journal may also include a keyed and/or a slotted locking member engageable with the inner body for imparting rotational torque transmission to the shaft, and a keyed and/or a slotted locking member engageable with a journal end connectable to a drive unit for driving the shaft for imparting rotational torque transmission to the shaft.  
           [0013]    The invention yet further provides an expansible shaft having an outer profile. The shaft may include an inner body having a longitudinal axis and at least one first coupling element, and at least two leaf elements movably coupled to the first coupling element of the inner body by means of at least one second coupling element. The leaf elements together substantially form the outer profile of the generally cylindrical expansible shaft. At least one thrusting element may be operatively disposed between the leaf elements and the inner body to move the leaf elements radially outwards relative to the longitudinal axis to increase an outer surface area of the shaft when in a first configuration, and allow the leaf elements to move radially inwards relative to the longitudinal axis to decrease the outer surface area of the shaft when in a second configuration.  
           [0014]    For the expansible shaft described above, the leaf elements may be resiliently biased radially inwards by means of a spring disposed between the inner body and the leaf elements. The spring may be either a leaf, wave or a coil spring. The first and second coupling elements may be complementary hooks. In a particular embodiment disclosed, the shaft may include two first and two second coupling elements, and three leaf elements. The leaf elements may include a plurality of knurls on an outer surface for increasing friction of engagement with a core of a product to be gripped. The shaft may further include an air journal removably coupled with the inner body and including an intake opening for permitting air to be supplied to the thrusting element for moving the leaf elements to the first configuration. The air journal may further include an exit opening for permitting air to be removed from the thrusting element for moving the leaf elements to the second configuration. The air journal may also include a keyed and/or a slotted locking member engageable with the inner body for imparting rotational torque transmission to the shaft, and a keyed and/or a slotted locking member engageable with a journal end connectable to a drive unit for driving the shaft for imparting rotational torque transmission to the shaft.  
           [0015]    Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings:  
         [0017]    [0017]FIG. 1 is an exploded isometric view of an expansible shaft according to the present invention, illustrating various components in their disassembled configuration;  
         [0018]    [0018]FIG. 2 is a front view of an inner body of the expansible shaft of FIG. 1;  
         [0019]    [0019]FIG. 3 is a right side view of the inner body of FIG. 2;  
         [0020]    [0020]FIG. 4 is a front view of an air journal of the expansible shaft of FIG. 1;  
         [0021]    [0021]FIG. 5 is a left side view of the air journal of FIG. 4;  
         [0022]    [0022]FIG. 6 is a right side view of the air journal of FIG. 4;  
         [0023]    [0023]FIG. 7 is a cross-sectional view of the air journal of FIG. 4, taken generally along line  7 - 7  in FIG. 6;  
         [0024]    [0024]FIG. 8 is a front view of a leaf of the expansible shaft of FIG. 1;  
         [0025]    [0025]FIG. 9 is a right side view of the leaf of FIG. 8;  
         [0026]    [0026]FIG. 10 is a front view of a leaf ring of the expansible shaft of FIG. 1;  
         [0027]    [0027]FIG. 11 is a right side view of the leaf ring of FIG. 10;  
         [0028]    [0028]FIG. 12 is a cross-sectional view of the leaf ring of FIG. 10, taken generally along line  12 - 12  in FIG. 10;  
         [0029]    [0029]FIG. 13 is a right side view of a journal end of the expansible shaft of FIG. 1;  
         [0030]    [0030]FIG. 14 is a rear view of the journal end of FIG. 13;  
         [0031]    [0031]FIG. 15 is a front view of the journal end of FIG. 13;  
         [0032]    [0032]FIG. 16 is a side view of a leaf retract spring of the expansible shaft of FIG. 1;  
         [0033]    [0033]FIG. 17 is a top view of the leaf retract spring of FIG. 16;  
         [0034]    [0034]FIG. 18 is an illustrative view of the expansible shaft of FIG. 1, illustrating the location of the thrusting means and the leaf retract springs, with the thrusting means disposed in the contracted configuration; and  
         [0035]    [0035]FIG. 19 is an illustrative view of the expansible shaft of FIG. 1, illustrating the location of the thrusting means and the leaf retract springs, with the thrusting means disposed in the expanded configuration. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views, FIGS. 1-19 illustrate an expansible shaft according to the present invention, generally designated  10 .  
         [0037]    As shown in FIGS. 1-3 and  8 - 9 , expansible shaft  10  may generally include a longitudinal axis A-A and leaves  12 ,  14 ,  16 , coupled with inner body  18  and movable radially outwardly with respect to body  18  by means of thrusting means  19 ,  20 ,  21 . For the exemplary embodiment disclosed, it should be noted that although three leaves  12 ,  14 ,  16  are shown, the present invention may employ two or more leaves so long as the leaves form a generally cylindrical expansible shaft or form the outer profile of a non-cylindrical shaft when coupled with inner body  18 . Each leaf  12 ,  14 ,  16  may include a generally semi-circular cross-section having a hollowed cavity  22  disposed generally centrally along the length thereof. The outer surface of each leaf  12 ,  14 ,  16  may be formed of a suitable friction material and include longitudinally extending knurls  15  for facilitating retention of a core and the like during driving or braking of shaft  10 . Hollow cavity  22  may include a bottom surface  24  having a central flat face  26  and mirror-image tapered surfaces  28  disposed adjacent flat face  26  for facilitating uniform expansion of thrusting means  19 ,  20 ,  21 .  
         [0038]    Still referring to FIGS. 1-3 and  8 - 9 , each leaf  12 ,  14 ,  16  may further include mirror-image hook members  30 ,  32  respectively engageable and retainable with complementary mirror-image hook members  34 ,  36  of inner body  18 . The top faces  38 ,  40  of each complementary hook member  34 ,  36  may be rounded for complementary engagement with internal wall  42  of leaves  12 ,  14 ,  16 . The bottom faces  44 ,  46  of each hook member  34 ,  36  may be machined or otherwise formed for complementary engagement with the surface of leaf shaft retract springs  98 , as illustrated in FIGS. 18 and 19. Thrusting means  19 ,  20 ,  21  may each comprise tubes which receive air pressure therein in a well-known manner to respectively expand and force leaves  12 ,  14 ,  16  radially outwardly with respect to body  18 . As shown in FIG. 1, each leaf  12 ,  14 ,  16  may include a predetermined gap  52  between each adjacent leaf when coupled to inner body  18  for permitting uniform expansion and contraction thereof relative to inner body  18 .  
         [0039]    Referring next to FIGS.  1 ,  4 - 7 ,  18  and  19 , expansible shaft  10  may include air journal  54  having a first diameter shaft  56  at one end thereof and a second smaller diameter shaft  58  at the other end thereof. The diameter of shaft  56  may be sized for insertion into hollow opening  60  provided in inner body  18 . Air journal  54  may include an air valve connection  62  provided on face  64  for connection to a suitable air supply (not shown) for providing air to thrusting means  19 ,  20 ,  21  through suitable openings  66  provided on thrust faces  68 ,  70 ,  72 . Faces  74 ,  76 ,  78  of air journal  54  may each include suitable openings  80  for attachment of top plate  81  for securing thrusting means  19 ,  20 ,  21  in place. Suitable valve means (not shown) may be provided for controlling the passage of air into openings  66  from air valve connection  62  for expansion of thrusting means  19 ,  20 ,  21  (see FIG. 19), and out through valve connection  62  for contraction of thrusting means  19 ,  20 ,  21  (see FIG. 18). Each face  68 ,  70 ,  72  (and adjacent faces  74 ,  76 ,  78 ) may include a pair of longitudinally protruding ribs  82  for generally controlling and guiding lateral expansion of thrusting means  19 ,  20 ,  21 .  
         [0040]    Still referring to FIGS. 1 and 4- 7 , air journal  54  may include three symmetrically disposed retention faces  84 ,  86 ,  88  each including internally threaded holes  90  for permitting removable retention of leaf ring  92 . Faces  74 ,  76 ,  78  adjacent retention faces  84 ,  86 ,  88  may each include a pair of internally threaded holes  94 ,  96  disposed on opposite ends of ribs  82  for permitting retention of leaf shaft retract springs  98 , described in detail below. The internal area of shaft  56  may be hollowed as at  100  for reducing the overall weight of air journal  54 .  
         [0041]    Referring next to FIGS. 1 and 10- 12 , leaf ring  92  may generally include a circular cross-section complementary to the cross-section of expansible shaft  10  in its contracted configuration. Ring  92  may further include an opening  102  for permitting connection of an air supply hose (not shown) to air valve connection  62 . Further openings  104  may be provided in circumferential alignment with holes  90  for permitting attachment of ring  92  to air journal  54  by suitable fasteners (not shown). A suitable opening  106  may be provided for insertion of journal end  108 .  
         [0042]    As shown in FIGS. 1 and 13- 15 , journal end  108  may be inserted through opening  106  and coupled with air journal  54 . A suitable alignment channel formed by protrusions  110  may be engaged with alignment member  112  provided on air journal  54  for facilitating engagement, alignment and retention of journal end  108  onto air journal  54 . Once protrusions  110  are aligned and engaged with alignment member  112 , a suitable fastener (not shown) may be used to fixedly couple journal end  108  to air journal  54 .  
         [0043]    Referring to FIGS. 1 and 16- 17 , as briefly discussed above, a pair of leaf shaft retract springs  98  may be respectively fastened to threaded holes  94 ,  96  disposed on opposite ends of ribs  82  on faces  74 ,  76 ,  78  of air journal  54  for resiliently biasing leaves  12 ,  14 ,  16  radially inwards for automatic retraction upon the release of air from thrusting means  19 ,  20 ,  21 . Leaf shaft retract springs  98  may engage faces  48 ,  50  of hook members  30 ,  32  such that when thrusting means  19 ,  20 ,  21  are expanded (see FIG. 19), springs  98  are compressed to substantially flatten their profile, and upon the release of air pressure to contract thrusting means  19 ,  20 ,  21  (see FIG. 18), springs  98  return to their normal “wavy” profile. It should be noted that although wave springs have been disclosed herein, those skilled in the art would appreciate in view of this disclosure that coil or leaf springs may likewise be used. Moreover, for an extended length shaft, additional sets of leaf shaft retract springs  98  may be used at predetermined intervals along the shaft length for providing an adequate biasing force for retracting leaves  12 ,  14 ,  16 .  
         [0044]    The opposite end face of expansible shaft  10  may be closed off by a suitable journal similar to air journal  54 , and a suitable ring and journal end  92 ,  108 , respectively.  
         [0045]    The various components described above for expansible shaft  10  may be formed by extrusion or machined, and may be formed of metal, plastic, fiber or composite material. The design, material selection, and fabrication of all components described above may be selected for minimizing the overall shaft weight and reducing machining and assembly time. The preferable material for the various components of shaft  10  may be aluminum and heat treated steel alloy for providing a strong interface between components, harder wear surfaces and optimal torque transmission from a drive unit (not shown) through the assembly of shaft  10 .  
         [0046]    Those skilled in the art would appreciate in view of this disclosure that various modifications may be made to expansible shaft  10  without departing from the scope of the present invention. For example, in addition to the various modifications discussed above, the overall outer surface profile of shaft  10  and therefore leaves  12 ,  14 ,  16  may be formed as needed (i.e. elliptical or other geometric shapes) for complementary engagement with a core to be gripped. Instead of the hook engagement means disclosed for coupling leaves  12 ,  14 ,  16  and inner body  18 , other engagement means may be utilized for complementary engagement between coupling leaves  12 ,  14 ,  16  and inner body  18 .  
         [0047]    Referring to FIGS. 3 and 5, for the expansible shaft  10  described above, air journal  54  may include a keyed or slotted locking feature defined by rectangular undercuts  116  adjacent the edges of faces  74 ,  76 ,  78 . Upon assembly of air journal  54  with inner body  18 , undercuts  116  are overlapped by protruding edges  118  of the three “U” shaped channels defined by hook members  34 ,  36  on inner body  18 , such when journal  54  is coupled to inner body  18 , protruding edges  118  rest within rectangular undercuts  116  and the surface edges along vertical plane  120  of inner body  18  contact the surface edges along vertical plane  122  of air journal  54 . The aforementioned keyed or slotted locking feature between air journal  54  and inner body  18  provides improvement in rotational torque transmission and facilitates assembly alignment. Moreover, as shown in FIG. 7, air journal  54  may also include a keyed or slotted locking feature being drive flats  114  of alignment member  112  for engagement with protrusions  110  of journal end  108  for likewise improving rotational torque transmission and facilitating assembly alignment.  
         [0048]    From the discussion above, the present invention provides an expansible shaft  10  which has been optimized in design for reducing operator handling issues due to reduced weight. Since rotational loads are inputted through symmetrically disposed hook elements, shaft  10  allows for higher torsional loads to be imparted during core gripping. Moreover, due to the uniform expansion and contraction characteristics of leaves  12 ,  14 ,  16 , the leaves evenly load delicate material cores to eliminate core distortion or damage.  
         [0049]    Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.