Abstract:
A flap sander is disclosed for use with a workpiece having a nonlinear profile. The flap sander comprises a cylindrical rotary head including a central hub concentric with an axis of rotation of the rotary head, and an inclined surface extending radially outward from the central hub. A plurality of abrasive flaps are detachably secured to the inclined surface of the rotary head and are aligned in a radial array radiating outward from central hub to the periphery of the rotary head. Each of the abrasive flaps comprises an unsecured working edge having a nonlinear profile that substantially matches the profile of the workpiece to provide an even sanding distribution across the workpiece profile independent of the shape of the profile.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application a 35 U.S.C. §111(a) continuation of PCT international application serial number PCT/US2009/036839 filed on Mar. 11, 2009, incorporated herein by reference in its entirety, which is a nonprovisional of U.S. provisional patent application Ser. No. 61/035,676 filed on Mar. 11, 2008, incorporated herein by reference in its entirety. Priority is claimed to each of the foregoing applications. 
         [0002]    The above-referenced PCT international application was published as PCT International Publication No. WO 2009/114630 published on Sep. 17, 2009 and republished on Nov. 5, 2009, and is incorporated herein by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    Not Applicable 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    Not Applicable 
       NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION 
       [0005]    A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. §1.14. 
       BACKGROUND OF THE INVENTION 
       [0006]    1. Field of the Invention 
         [0007]    This invention pertains generally to sanding apparatus, and more particularly to a flap sanding apparatus. 
         [0008]    2. Description of Related Art 
         [0009]    Flap wheel sanding has been used in a number of different applications and on many different types of substrates. In the wood working industry, flap sanding is used widely in sanding and finishing the surface of various shapes, such as turned columns and spindles, curved/uneven furniture parts etc. The flap sander, by design, is very flexible allowing it to easily conform to various shaped surfaces. 
         [0010]      FIGS. 1 and 2  illustrate a prior art flap sander applied to typical cross sections  10  and  20  of a raised panel door for a kitchen cabinet, and outside edge profile of a door. The flap sander  12  generally comprises of a rotary head that retains and positions individual strips  14  of mineral abrasive, commonly called sand paper, that is attached to a flexible carrier or backing. The abrasive strips extend in a radial manner and are generally evenly spaced around the circumference of the head. The strips generally comprise a plurality of slits  16  that allow the straight linear working edge  18  of the sander to conform to the varying profile of the surface to be treated. 
         [0011]    By design, existing flap sanders are not specific to any particular shape and can adapt to many different shapes. The advantage of the flexibility is lost, however, in its ability to uniformly finish a specific shaped area in that the finished results can be too aggressive on protruding areas of a surface (e.g. locations A and B in  FIGS. 1 and 2 ) too light in recessed areas of a surface. 
         [0012]    Accordingly, an object of the present invention is a flap sander that provides even sanding across a specific non-liner profile work surface. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    An aspect of the invention is a sanding apparatus for use with a workpiece to be finished, the workpiece having a substantially nonlinear profile. The apparatus includes a plurality of abrasive flaps secured to a rotary head. The abrasive flaps are generally aligned in a radial array radiating outward from an axis of rotation of the rotary head. Each of the abrasive flaps comprises an unsecured working edge having a nonlinear profile that substantially matches the profile of the workpiece. 
         [0014]    In one embodiment of the current aspect, a plurality of support members are secured to the rotary head, each support member being positioned radially adjacent and parallel to a corresponding abrasive flap and comprising an unsecured end substantially matching the working end of the abrasive flap. 
         [0015]    In a preferred embodiment, the working edge of the flap is uninterrupted across the length of the flap, i.e. slits in the flap are not required for the flap to conform to the profile of the workpiece. Accordingly, the working edge of the flap is configured to evenly distribute pressure across the length of the workpiece profile. 
         [0016]    In another preferred embodiment, the abrasive flaps are releasably mounted to the rotary head for ease of replacement with a new flap (e.g. non-worn) or different flap having a different profile to work on a different workpiece. In one mode, each abrasive flap slideably engages a radial slot in the rotary head. 
         [0017]    In another embodiment, the working edge profile comprises a first segment having a first path and a second segment having a second path different from the first path. Any number of segments and different paths may make up the profile. The segments may have curves of differing curvilinear or linear shapes or having different slopes to correspond to features of the workpiece profile. 
         [0018]    Another aspect is a flap sander for use with a workpiece to be finished, said workpiece having a substantially nonlinear profile. The sander has a cylindrical rotary head comprising a central hub concentric with an axis of oration of the rotary head, and an inclined surface extending radially outward from the central hub. A plurality of abrasive flaps are secured to the inclined surface of the rotary head, and aligned in a radial array radiating outward from central hub to the periphery of the rotary head. Each of the abrasive flaps comprises an unsecured working edge having a nonlinear profile that substantially matches the profile of the workpiece. 
         [0019]    In one embodiment, the inclined surface forms a conical surface radiating outward from the central hub, and the hub extends as a cylinder a specified length beyond the conical surface. 
         [0020]    Another aspect is a method of sanding a workpiece, comprising: providing a rotary head having a plurality of abrasive flaps having an unsecured working edge with a nonlinear profile that substantially matches the profile of the workpiece; positioning a rotary head adjacent the workpiece such that at least one of the abrasive flaps substantially lines up with the workpiece profile; and rotating the rotary head to sand the profile with substantially even pressure across the profile. 
         [0021]    In one embodiment of the current aspect, the plurality of abrasive flaps are aligned in a radial array radiating outward from an axis of rotation of the rotary head along with a plurality of support members secured to the rotary head; wherein each support member is positioned radially adjacent and parallel to a corresponding abrasive flap; and wherein each support member comprises an unsecured end substantially matching the working end of the abrasive flap to support the abrasive flap as the flap is applied to the workpiece. 
         [0022]    In another embodiment, the unsecured end of the abrasive flap curves over the support member when applied to the workpiece to form a curvilinear sanding work surface in contact with the workpiece. 
         [0023]    Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0024]    The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: 
           [0025]      FIG. 1  is sectional view of a prior art flap sander applied to a raised panel door profile. 
           [0026]      FIG. 2  is sectional view of a prior art flap sander applied to an edge profile. 
           [0027]      FIG. 3  is a plan view of the flap sander of the present invention. 
           [0028]      FIG. 4  is a sectional view of the flap sander shown in  FIG. 3 , shown adjacent to a raised panel door profile. 
           [0029]      FIG. 5  is a sectional view of an alternative embodiment of the flap sander of the present invention, shown adjacent to a door edge profile. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in  FIG. 3  through  FIG. 5 . It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein. 
         [0031]      FIG. 3  illustrates a plan view of the underside of flap sander rotary head  30  of the present invention. The flap sander  30  comprises a head body  32  having a plurality of abrasive flaps  34  radially disposed generally perpendicular to the lower angled surface of the head body  32 . 
         [0032]    Referring to the sectional view of  FIG. 4 , the abrasive flaps are coupled to a flexible backing or carrier  56  that slides into a plurality of radially oriented slots  44  in the rotary head body  32 . In a preferred embodiment, the abrasive flap  34  and carrier  56  may be interchangeably disposed in slot  44  by placing the carrier  56  at the outside circumference  42  of the head body  32  and slideably translating the carrier  56  and flap  34  radially inward along the slot  44  until the carrier  56  is fully retained within the slot. A retaining ring  60  may then be placed around outer periphery  42  to retain the flaps  34  in place. 
         [0033]    The slot  44  and carrier  56  may comprise a dovetail configuration that retains the carrier  56  and flap  34  retained in the head body  32  even in the presence of a tensile load place on the flap  34 . 
         [0034]    Adjacent to one side of each abrasive flap  34  is a support member  36  that provides lateral support for the flaps  34  while the sander is treating a surface. The support member  36  generally comprises a compliant, resilient material that increases the lateral stiffness of the abrasive flap  34  in the direction of the sanding force. Support member  36  may comprise a variety of different materials, such as a brush, foam, extruded polymer, or the like. 
         [0035]    The support member  36  trails each of the abrasive flaps  34  in the direction of the sander (as shown in  FIG. 3 , the rotation of the head is clockwise). As shown in  FIG. 4 , the support member  36  follows the profile of the flap  34 , but does not extend outward as far as the flap  34 . This allows the flap  34  to bend and form a rounded working surface around the support member  36  when applied to the surface to be treated. 
         [0036]    The embodiment of  FIG. 3  shows a series of 16 abrasive flaps  34  and support members  36  disposed radially within 16 slots  44 . However, it is appreciated that any number of slots  44  or flaps  34  may be used (e.g. 8 or 24 slots). The sander  30  may also be run with some of the slots  44  empty (e.g. abrasive flaps only positioned in every other slot  44 ). 
         [0037]    Referring to  FIG. 4 , the head body  32  comprises a central hub  40  with a large diameter bore  38  for retaining a rotary shaft and collet (not shown). The central hub is substantially coincident with the axis of rotation  48  of the head body  32 . The bore  38  may also have a conical taper  58  to facilitate attachment to the rotary shaft. The additional rotational mass at the center of the head body  32  provides stability at high speeds. 
         [0038]    The bottom surface of the head body  32  may be sloped at angle θ with respect to the hub axis, i.e. comprise a conical shape, to conform to the desired work surface. The slope of the conical surface, defined by angle Θ in  FIG. 4 , may vary from 0° to 90°, and is generally fixed with each head body  32  (e.g. a kit of head bodies may be provided with varying increments (e.g. 5 degree increments) from 0° to)90°. 
         [0039]    As seen in  FIG. 4 , the edge profile  50  matches, or substantially matches, the profile D of the cross-section  10  to be treated. Generally, edge profile  50  comprises a nonlinear edge having a first section or feature  52  having a path with a different slope or curve than a second profile feature  54 . The support element  36  preferably follows the profile  50  (at a lesser extension from the head body  32 ) of the flap  34  so as to provide support for the flap  34  conforming to the treatment surface D. As shown in  FIG. 4 , the first part  52  of profile  50  curves concavely radially inward, and second part  54  curves concavely radially outward. The edge profile  50  may be varied to form any number of edge shapes having segments that are curved or at varying angles with respect to each other to substantially match the profile to be sanding. In this configuration, the abrasive flap  34  sands evenly across the profile  10  without putting undue pressure or abrasion on any particular section. 
         [0040]    For purposes of this description, a “nonlinear path” is a path that does not follow a straight line across the length of the flap profile  50  as a whole. While first and second sections  52 ,  54  are shown as curvilinear paths, it is appreciated that one, or both, of the paths of sections  52 ,  54  may comprise a linear path. For example, the paths of sections  52 ,  54  may each be straight lines that are at different slopes with respect to each other, thus creating a nonlinear profile across the length of the flap profile  50 . It is also appreciated that any number of differently shaped sections may be used to generate a profile. 
         [0041]    While it is appreciated that the features of the present invention are particularly advantageous for use on work pieces having nonlinear profiles, it is also appreciated that the rotary head  32  may be used with flaps that have a linear profile to match the shape of a planar work surface to be treated. 
         [0042]      FIG. 5  shows an additional embodiment of flap sander  70  having a larger working angle φ, and abrasive flaps  74  having an edge profile  90  shaped to match the sectional profile of a door&#39;s outside edge. Support element  76  sharing a similar profile may also be positioned adjacent each flap  74 . 
         [0043]    In this configuration, the carriers  86  holding abrasive flaps  74  are installed from a radially inward location adjacent to central bore  78 , and translated radially outward along slot  84  until the carrier  86  is fully seated within the slot  84 . Cap  96  may then be installed over the bottom chamfered portion  80  of bore  78  to retain the flaps  74  in place. 
         [0044]    As seen in  FIG. 5 , the profile  90  of the abrasive flap  74  is generally nonlinear and substantially matched to the profile E of the door edge cross-section  20 . The profile in this case has a concave curve  92  radially inward and adjacent to convex curve  94 . This edge profile provides an even abrasive distribution across the surface of the area to be treated. 
         [0045]    It is appreciated that while two different edge profiles are detailed above, the edge profile of the abrasive flaps of the present invention may be modified to substantially match any number of different surface features. In addition, it is appreciated that various feature of each of the embodiments listed above may be interchangeably combined. 
         [0046]    Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”