Abstract:
A light-weight mechanical spacer is provided and includes first and second housing plates and a plurality of shafts or posts. The housing plates include a generally circular shape and include a coaxial bore formed therethrough for receiving an arbor. The first and second housing plates are connected by a plurality of shafts to both define the overall width of the spacer as well as to provide increased strength. The shafts enable the light-weight design as they effectively replace the solid mass of steel commonly found in conventional spacers.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Nos. 60/415,038, filed on Oct. 1, 2002 and 60/452,874 filed on Mar. 7, 2003. The disclosure of these applications is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to mechanical spacers, and more particularly, to a light-weight mechanical spacer for use in a metal slitting operation.  
         BACKGROUND OF THE INVENTION  
         [0003]    In slitting operations such as metal slitting and the like, it is imperative to be able to provide a wide range of steel widths to consumers. Further, it is desirable that a single slitting machine be capable of quickly and inexpensively slitting a coil of metal into a plurality of different widths for various applications. Further yet, it is desirable to maintain tight tolerances on the cut metal to ensure that the metal will be usable in its particular application and will perform as desired. To these ends, spacers play a significant role in the conventional slitting of metal.  
           [0004]    Conventional slitter tooling consists generally of two sets of round spacers and a series of knives. The spacers and knives are received by upper and lower arbors, whereby the upper arbor is offset and opposed from the lower arbor. In operation, a metal coil is unwound and passes between the upper and lower arbors for slitting. Specifically, as the coil passes between the arbors, the meal is sheared into strips of a predetermined width through the cooperation of the knives on each of the upper and lower arbor. In this manner, the horizontal distance between a pair of knives determines the output width of the strip.  
           [0005]    The distance between a pair of knives is commonly referred to as horizontal clearance and is generally set by employing a series of mechanical spacers. By way of example, if a two inch wide strip is desired, the top and bottom arbors will be packed with a series of knives and two inch spacers to provide the desired horizontal clearance between each knife. Having each knife separated by a two-inch spacer results in a sheet of metal originally measuring twenty-four inches in width prior to slitting, being cut into a series of twelve two-inch strips after slitting.  
           [0006]    Conventional spacers are commonly constructed of solid steel and generally include a central bore for receiving an arbor. The overall width of the spacer determines the horizontal clearance between the knives and ultimately the width of the strip exiting the slitter, as previously discussed. Conventional spacers, while adequately maintaining the horizontal clearance between the knives, are typically very heavy and, as a result, difficult to change. Further, because the solid steel spacers are heavy and difficult to maneuver, the time required to make a tooling change, as required to cut different strip widths, is increased, thus increasing cost and waste.  
           [0007]    Because the requirements for different strip widths change throughout a typical day, and because slitting operations produce varying widths on the same tooling, the rate at which a machine is re-tooled to cut different widths of metal is very important. As can be appreciated, the longer it takes to change a series of spacers and knives between operations, the more time the machine sits idle. Such increases in downtime generally decreases the overall efficiency of the slitting operation and will ultimately decrease profits and productivity.  
           [0008]    Therefore, a spacer that improves the efficiency of a slitting operation by enabling a quicker change over between varying strip widths, while maintaining a tight tolerance, is desirable in the industry.  
         SUMMARY OF THE INVENTION  
         [0009]    Accordingly, the present invention provides a light-weight mechanical spacer constructed out of first and second housing plates and a plurality of shafts or posts. The housing plates define a generally circular shape and include a coaxial bore formed therethrough for receiving an arbor. The first and second housing plates are connected by a plurality of shafts to both define the overall width of the spacer as well as to provide increased strength. The shafts enable the light-weight design as they effectively replace the solid mass of steel commonly found in conventional spacers. The light-weight spacer effectively reduces the amount of weight that must be lifted each time the tooling requires changing. In this manner, the light-weight spacer enables a quicker tooling change-over, thereby increasing efficiency and improving the overall production of a slitting operation.  
           [0010]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0012]    [0012]FIG. 1 is a perspective view of a first embodiment of a mechanical spacer in accordance with the principals of the present invention;  
         [0013]    [0013]FIG. 2 is a perspective view of a second embodiment of a mechanical spacer in accordance with the principals of the present invention;  
         [0014]    [0014]FIG. 3 is a graphical representation of the first and second mechanical spacers of FIGS. 1 and 2 as used in an exemplary slitting operation;  
         [0015]    [0015]FIG. 4 is a second embodiment of a mechanical spacer in accordance with the principals of the present invention;  
         [0016]    [0016]FIG. 5 is a side view of a mechanical space in accordance with the principals of the present invention incorporated onto an arbor; and  
         [0017]    [0017]FIG. 6 is a side view of a mechanical spacer in accordance with the principals of the present invention incorporated onto an arbor. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0019]    With reference to the FIG. 1, a mechanical spacer  10  is provided and includes a first housing plate  12 , a second housing plate  14 , and a plurality of shafts  16 . The shafts  16  fixedly connect the first and second housing plates  12  and  14  and provide a predetermined spaced relationship therebetween.  
         [0020]    The first housing plate  12  includes a generally circular shape having an inner and outer surface  18  and  20  and a first bore  22  formed therethrough. The second housing plate  14  includes a generally circular shape and includes an inner and outer surface  24  and  26  and a second bore  24  formed therethrough. The first and second housing plates  12  and  14  are fixedly connected by shafts  16  and are held in a fixed relationship relative one another thereby.  
         [0021]    The shafts  16  serve to interconnect the first and second housing plates  18 ,  20  and also to set the overall width of the spacer  10 , as will be discussed further herein below. The shafts  16  include a generally cylindrical body  30  and a first and second end  32  and  34 . The length of each shaft  16  determines the space between the first and second housing plates  12  and  14  and, as such, determines the overall width of the spacer  10  as measured between the outer surface  20  of the first housing plate  12  and the outer surface  26  of the second housing plate  14 . The first end  32  of each shaft  16  is received by the inner surface  18  of the first housing plate  12  and is fixedly mounted thereto by a suitable means such as a weld or a press fit. The second end  34  of each shaft  16  is received by the inner surface  24  of the second housing plate  14  and is similarly mounted thereto by a suitable means such as a weld or a press fit. While a weld and a press fit are disclosed, it should be understood that any suitable manner of attaching the post  16  to the inner surfaces  18  and  24  of the first and second housing plates  12  and  14  is anticipated and should be considered within the scope of the present invention. It should further be understood that while a cylindrical body  30  is disclosed, the posts  16  could have any suitable cross-sectional shape such as, but not limited to, a square or triangular shape, and should be considered within the scope of the present invention.  
         [0022]    Having a shaft  16  fixedly attached to the inner surface  18  of the first housing plate  12  and concurrently to the inner surface  24  of the second housing plate  14  sets the relative relationship between the first and second housing plates  12  and  14 . In an effort to strengthen the structure of the mechanical spacer  10 , a plurality of shafts  16  are included and are similarly attached to the first and second housing plates  12  and  14 , as previously described. In this manner, the mechanical spacer  10  includes a plurality of shafts  16  radially spaced from a central axis to support the first and second housing plates  12  and  14  and to provide an arrangement for setting the overall width of the mechanical spacer  10 .  
         [0023]    To change the width of the mechanical spacer  10 , the shafts  16  can be constructed of varying lengths depending on the particular application and desired width of the spacer  10 . Specifically, at the time of manufacturing, the shafts  16  can be adjusted (i.e. shortened or lengthened) prior to their assembly to the first and second housing plates  12  and  14 , whereby the amount of adjustment will be determined by the desired overall width of the mechanical spacer  10 . It should be understood that the lengths of the shafts  16  must be uniform for each mechanical spacer  10 . Providing the shafts  16  with a uniform length ensures that the outer width of the mechanical spacer  10  is constant, thereby providing an accurate and reliable tolerance, as will be discussed further below.  
         [0024]    Upon attachment of the first housing plate  12  to the second housing plate  14 , it is imperative that the first bore  22  of the first housing plate  12  is coaxially aligned with the second bore  28  of the second housing plate  14 . The alignment of the first and second bore  22  and  28  forms a central bore  36  extending through the mechanical spacer  10 . The central bore  36  receives an arbor  38 , whereby the arbor  38  is a generally elongate cylindrical member. In one embodiment, the arbor is rotatably driven by a slitter tool  40  and serves to transmit the rotation from the slitter tool  40  to a series of knives  42  as best shown in FIG. 3. The spacing between the knives  42  determines the width of a coil of steel (not shown) after slitting, whereby the distance between the knives  42  is governed by the position of the spacers  10 . Because the spacing of the knives  42  is critical to a successful slitting operation with regard to maintaining tolerances and the like, the mechanical spacers  10  must rotate with the arbor  38  and maintain their relative position throughout the operation.  
         [0025]    In one embodiment, the first and second housing plates  12  and  14  have a key  44  disposed therebetween extending from an inner surface of bore  36  generally towards a central axis of rotation of the mechanical spacer  10 , as best shown in FIG. 1. The key  44  is received by a mating slot  45  formed in the arbor  38  such that as the mechanical spacer  10  is slid onto the arbor  38  the key  44  is concurrently received by the slot  45 , as best shown in FIG. 5. In this manner, relative rotation between the arbor  38  and the mechanical spacer  10  is prohibited. It should be noted that the mechanical spacer  10  may be used concurrently with another mechanical spacer  10  to accomplish a relative distance between two knives  42  generally equal to the combined widths of the two mechanical spacers  10 , as best shown in FIG. 3. In this manner, the cooperation of the key  44  and the slot  45  serves to align the spacers  10  and ensure that the shafts  16  of the respective spacers  10  are aligned. Alignment of the shafts  16  ensures that the compressive strength of spacers  10  together is maximized. Specifically, as load is applied to either spacer  10 , it is effectively transmitted by the shafts therebetween. This relationship maintains the integrity of the individual spacers  10  and ensures a slitting operation that is capable of maintaining a tight tolerance.  
         [0026]    With reference to FIGS. 2 and 6, a mechanical spacer in accordance with a second embodiment is illustrated and generally identified at reference character  10 ′. In view of the related combination between the embodiments of FIGS. 1 and 2, like reference numbers will be used to identify like elements. In the second embodiment, the first and second housing plates  12  and  14  have a recess or keyway  46  disposed therebetween extending across the width of the spacer  10 ′ longitudinally along central bore  36  as best shown in FIG. 2. The keyway  46  receives a key  47  disposed generally along a length of the arbor  38  such that as the mechanical spacer  10 ′ is slid onto the arbor  38  the keyway  46  receives the key  47 . In this manner, relative rotation between the arbor  38  and the mechanical spacer  10 ′ is prohibited.  
         [0027]    It should again be noted that the mechanical spacer  10 ′ may be used concurrently with another mechanical spacer  10 ′ to accomplish a relative distance between two knives  42  generally equal to the combined widths of the two mechanical spacers  10 ′, as best shown in FIG. 3. In this manner, the cooperation of the keyway  46  and the key  47  serves to align the spacers  10 ′ and ensure that the shafts  16  of the respective spacers  10 ′ are aligned. Alignment of the shafts  16  ensures that the compressive strength of spacers  10 ′ together is maximized. Specifically, as load is applied to either spacer  10 ′, it is effectively transmitted by the shafts therebetween. This relationship maintains the integrity of the individual spacers  10 ′ and ensures a slitting operation that is capable of maintaining a tight tolerance.  
         [0028]    The foregoing description enables a traditional spacer to be replaced by a lighter-weight mechanical spacer  10 . Specifically, by replacing the traditional solid steel spacer with a mechanical spacer  10  having support posts  16  in the place of a solid steel mass, suitable strength characteristics can be achieved using less material. In an effort to fill the voids between the first and second housing plates  12 ,  14  and the posts  16 , the mechanical spacer  10  may be optionally provided with a suitable material such as, but not limited to, a structural foam or adhesive. The filler material used should have a lower weight than the steel traditionally used to realize the benefit of the light-weight design and will serve to give the outer edge of the mechanical spacer  10  a uniform and smooth appearance. It should be understood that the filler material is optional and bears no weight on the performance of the present invention. The material may increase the overall strength of the spacer  10  but the intent of adding the material is for aesthetic purposes only.  
         [0029]    While the first and second housing plates  12  and  14  have been described as including a keyway  46  for interaction with key  47  formed on arbor  38 , it should be understood that the spacers  10  of the present invention could include first and second apertures  22  and  28  having a generally constant circular shape. In this manner, apertures  22  and  28  are matingly received by the circular-shaped arbor  38  and are held in relative position along the arbor  38  due to the interaction between adjacent spacers  10  and knives  42 , thereby obviating the necessity for a keyway  46  and key  47 . In other words, in situations where a key  47  is not available on an arbor  38 , the spacers  10  of the present invention are still usable provided each spacer  10  is sandwiched between adjacent spacers  10  or knives  42 .  
         [0030]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.