Abstract:
The present invention is an abrading system for a hand power tool including a base with a first end portion and a second end portion and configured to couple with the output shaft of a hand power tool, a flexible substrate having a first extending portion coupled with the first end portion and extending outwardly from the first end portion, a second extending portion coupled with the second end portion and extending outwardly from the second end portion, and a middle portion spaced apart from the base and extending between the first extending portion and the second extending portion, and an abrading material attached to the flexible substrate.

Description:
FIELD OF THE INVENTION 
     The present invention relates to hand tools and more particularly to an accessory for abrading contoured work pieces. 
     BACKGROUND 
     Hand held power tools are widely used by many people including professionals, craftspeople, homeowners, and artists. These power tools typically include an outer housing designed to be easily held within human hands. The housing retains an electric motor which is operable to drive a chuck of the power tool. The movements provided by various power tools include reciprocating, rotating, and orbiting patterns. The movement provided with a particular tool is dependent upon the purpose of the tool. 
     One purpose for which power tools may be used is the abrading of contoured surfaces. Abrading tools typically include rotating devices such as drum sanders, belt sanders, and disc sanders and orbital devices such as random orbit sanders. Each type of sander provides different benefits and limitations for different abrading tasks. For example, drum sanders are very effective for use in abrading interior curves of a work piece. While drum sanders may be used for external curves, care must be taken to avoid altering the contour of the work-piece since the shape of the abrading surface is not complementary to the shape of the work piece. 
     Disc sanders and orbiting sanders may also be used to abrade external curves of a work piece. The abrading surface of prior art disc sanders and orbiting sanders, however, is substantially flat. Thus, while these types of sanders are generally more controllable than drum sanders, non-conformance with the shape of the work piece results in a relatively small contact area between the abrading surface and the work piece. A small contact area focuses the effect of the abrading device on a localized area of the work piece. Thus, the contour of the work piece may be inadvertently altered. 
     Additionally, as the surface contact area of the abrading material is reduced, the abrading material becomes more susceptible to localized failure. Thus, an abrading sheet attached to an orbital sander may rip at the location of the abrading material which is in contact with the work piece. While the damaged area may be quite small, the entire abrading sheet may be rendered unusable. 
     A number of specialized accessories have been developed to assist in abrading work pieces with various contours. These accessories, however, tend to be relatively expensive. Additionally, specialized contouring devices are typically specifically designed for contours of a particular shape and size. Thus, a large number of the accessories must be maintained to allow for abrading contours of different shapes and sizes. 
     Other devices which may be used to abrade contoured work pieces use a resilient pad placed over a sanding plate. While the use of a pad increases the surface area of the abrading material in contact with the work piece, pads conform to only slight contours. Accordingly, contour abrading is frequently still done by hand using a piece of sand paper. 
     Therefore, a contour abrading device that may be used with an orbital sander that conforms the abrading material to a variety of contours would be beneficial. 
     SUMMARY 
     The present invention is an abrading system for a hand power tool including a base with a first end portion and a second end portion and configured to couple with the output shaft of a hand power tool, a flexible substrate having a first extending portion coupled with the first end portion and extending outwardly from the first end portion, a second extending portion coupled with the second end portion and extending outwardly from the second end portion, and a middle portion spaced apart from the base and extending between the first extending portion and the second extending portion, and an abrading material attached to the flexible substrate. 
     In one embodiment an abrading kit for use with a hand power tool includes at least one base with a first end portion and a second end portion and configured to couple with the output shaft of a hand power tool, and a plurality of flexible substrates, each of the plurality of flexible substrates having (i) a first extending portion for coupling with the first end portion so as to extend outwardly from the first end portion, (ii) a second extending portion for coupling with the second end portion so as to extend outwardly from the second end portion, and (iii) a middle portion extending between the first extending portion and the second extending portion and configured to couple with at least one abrading sheet, each of the plurality of flexible substrates having a flexibility different from the flexibility of the other of the plurality of flexible substrates. 
     In a further embodiment, an abrading system for a hand power tool includes a base with a first base end portion and a second base end portion and configured to couple with the output shaft of a hand power tool, the base defining a base length between a first coupler at the first base end portion and a first coupler at the base second end portion, a flexible substrate having a first substrate end portion coupled with the first base end portion, a second substrate end portion coupled with the second base end portion, and a middle portion extending between the first extending portion and the second extending portion, the flexible substrate defining a working length wherein the working length is greater than the base length, and an abrading material attached to the flexible substrate. 
     These and other advantages and features of the present invention may be discerned from reviewing the accompanying drawings and the detailed description of the preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may take form in various system and method components and arrangement of system and method components. The drawings are only for purposes of illustrating exemplary embodiments and are not to be construed as limiting the invention. 
         FIG. 1  depicts a top perspective view of a contour abrading device coupled with a hand-held power tool in accordance with principles of the invention; 
         FIG. 2  depicts a bottom perspective view of the contour abrading device of  FIG. 1 ; 
         FIG. 3  depicts an exploded perspective view of the contour abrading device of  FIG. 1 ; 
         FIG. 4  depicts a cross-sectional view of the contour abrading device of  FIG. 1  showing the working length and base length of the device and identifying a primary abrading surface and two secondary abrading surfaces 
         FIG. 5  depicts the contour abrading device and power tool of  FIG. 1  positioned above a work piece with a contoured surface; 
         FIG. 6  depicts the contour abrading device and power tool of  FIG. 1  pressed against the contoured surface of the work piece of  FIG. 5  with the contour abrading device deformed to conform to the shape of the contoured surface; 
         FIG. 7  depicts a cross-sectional view of the contour abrading device of  FIG. 1  deformed to conform to the shape of a round work piece; 
         FIG. 8  depicts a cross-sectional view of the contour abrading device of  FIG. 1  deformed to conform to the shape of a round work piece that has a radius of curvature larger than the radius of curvature of the work piece of  FIG. 7 ; 
         FIG. 9  depicts a kit including a base and three flexible substrates that can be removably coupled to the base wherein the flexible substrates are patterned such that each of the flexible substrates has a flexibility different from the flexibility of the other flexible substrates; and 
         FIG. 10  depicts a kit including a base and three flexible substrates that can be removably coupled to the base wherein the flexible substrates are provided with different working lengths such that each of the flexible substrates has a flexibility different from the flexibility of the other flexible substrates; 
         FIG. 11  depicts a kit including a base and three flexible substrates that can be removably coupled to the base wherein the flexible substrates are made from different materials such that each of the flexible substrates has a flexibility different from the flexibility of the other flexible substrates; and 
         FIG. 12  depicts a kit including a base and three flexible substrates that can be removably coupled to the base wherein the flexible substrates are provided with different thicknesses such that each of the flexible substrates has a flexibility different from the flexibility of the other flexible substrates. 
     
    
    
     DESCRIPTION 
     Referring to  FIG. 1 , a contour abrading device  100  is shown mounted to a hand-held power tool  102 . The hand-held power tool  102  in this embodiment is a random orbit device, although other devices may be used to provide movement for the contour abrading device  100 . The contour abrading device  100  is removably mounted to the hand-held power tool  102  by a mandrel assembly  104 . Alternatively, a contour abrading device may be provided with an integral mandrel for coupling with a power tool that includes a collet assembly. 
     With reference to  FIGS. 2-4 , the contour abrading device  100  includes a base  106 , a flexible substrate  108  and an abrading sheet  110 . The base  106  includes a coupling feature  112  for use in mounting the contour abrading device  100  with the power tool  102 , although other coupling members could be used. The base  106  further includes four holes  114 ,  116 ,  118 , and  120  which receive four rivets  122 ,  124 ,  126 , and  128 . 
     The four rivets  122 ,  124 ,  126 , and  128  extend from the base  106  through four holes  130 ,  132 ,  134 , and  136  in the flexible substrate  108 . In alternative embodiments, the flexible substrate is removably attached to a base using, for example, screws or bolts. In another alternative, the substrate can be adhesive bonded on the base. In yet another alternative, the substrate can be insert molded thermoplastic elastomer over a thermoplastic base. The flexible substrate  108  includes an opening  138 . The opening  138  is located at the center portion of the flexible substrate  108 . The abrading sheet  110  is attached to the flexible substrate  108  using an adhesive. Other techniques for attaching an abrading sheet to a substrate may be used including hook and loop techniques. 
     As shown in  FIG. 4 , the flexible substrate  108  has a working length  150  that is larger than the base length  152 . The working length  150  is the length of the flexible substrate  108  between the rivets  122 ,  124  and  126 ,  128 . The base length  152  is the length of the base  106  between the rivets  122 ,  124  and  126 ,  128 . Because the working length  150  is longer than the base length  152 , a gap area  154  is formed between the base  106  and a primary abrading portion  156 . Two secondary abrading portions  158  and  160  are formed adjacent to the primary abrading portion  156 . While a work piece may be abraded using any portion of the abrading sheet  110 , most abrading of contoured areas is performed using the primary abrading portion  156 . 
     For example, the work piece  162  of  FIG. 5 , which includes a contoured portion  164 , may be abraded by positioning the primary abrading portion  156  of the contour abrading device  100  above the contoured portion  164  and energizing the power tool  102 . Positioning the primary abrading portion  156  against the work piece  162  and applying pressure in the direction of the arrow  166  causes the flexible substrate  108  to deform, thereby conforming to the shape of the work piece  162  as shown in  FIG. 6 . 
     The extent to which the contour abrading device  100  conforms to the contour of a work piece is a function of the force with which the contour abrading device  100  is held against the work piece, the physical characteristics of the particular material used to form the flexible substrate  108  and the mismatch between the working length  150  and the base length  152 . For a given applied force, increasing the mismatch allows more conformity as does increasing the flexibility of the substrate. One group of materials which may be used as a flexible substrate material to provide elasticity and strength are TPEs (thermoplastic elastomers). 
     The mismatch between the working length  150  and the base length  152  contributes to the flexibility of the flexible substrate  108  and allows the contour abrading device  100  to conform to work pieces exhibiting a variety of contours. By way of example, the work piece  170  of  FIG. 7  is a circular work piece. The contour abrading device  100 , which is not shown connected to a power tool, has been deformed from the original shape of the contour abrading device  100 ′ by forcing the contour abrading device  100  against the work piece  170 . The curvature of the flexible substrate  108  in the secondary abrading portions  158  and  160  provides even pressure across the primary abrading portion  156  which conforms to the work piece  170  over a substantial area of the curved surface of the work piece  170 . 
     The work piece  172  of  FIG. 8  is a circular work piece that has a radius that is larger than the radius of the work piece  170 . Nonetheless, the contour abrading device  100 , which is not shown connected to a power tool, has been deformed from the original shape of the contour abrading device  100 ′ to conform to the larger radius of the work piece  172 . This is possible since the flexible substrate  108  can be forced into different configurations in the secondary abrading portions  158  and  160  to provide even pressure across the primary abrading portion  156  for contours having a variety of radii. 
     While the contour abrading device  100  may be used for a variety of contours, increasing the contact area between the contoured surface of a work piece and the abrading sheet generally requires increased pressure on the particular contour abrading device so as to increase the deformation of the flexible substrate. The abrading device may be modified in various ways, however, to mitigate the amount of force that is required. If desired, a kit may be provided with flexible substrates made of different materials, each of the materials exhibiting different elasticities. Alternatively, a single material may be used to provide different flexibility. 
     By way of example, the top hole  138  (see  FIG. 3 ) results in a reduced amount of material in the flexible substrate  108  at the central portion of the primary abrading portion  156 . Accordingly, the resistance to deformation of the flexible substrate  108  at the central portion of the primary abrading portion  156  is less than the resistance to deformation of the secondary abrading portions  158  and  160 . Thus, selective patterning of material may be used to modify the operating characteristics of different contour abrading devices. 
     The kit  180  of  FIG. 9  incorporates selective patterning to provide a variety of operating characteristics for the contour abrading system. The kit  180  includes a base  182  and three flexible substrates  184 ,  186 , and  188 . The substrates  184 ,  186 , and  188  include a surface configured for hook and loop coupling with an abrading sheet (not shown). Abrading sheets, along with couplers for removably attaching the flexible substrates  184 ,  186 , and  188  to the base  182 , may be provided in the kit  180 . The ability to removably couple abrading sheets using hook and loop coupling enables each of the three flexible substrates  184 ,  186 , and  188  to be used with a variety of abrading sheets. 
     Each of the flexible substrates  184 ,  186 , and  188  provide a different rigidity. The flexible substrate  184  is the most rigid of the three substrates and may be used on contoured surfaces with a relatively large radius of curvature. The flexible substrate  186  is patterned with an opening  190 . Accordingly, the flexible substrate  186  is less rigid than the flexible substrate  184 . The flexible substrate  186  is thus configured for use on contoured surfaces with radii of curvature smaller than those associated with the flexible substrate  184 . Alternatively, using the flexible substrate  186  on work pieces having larger radii of curvature allows for more surface area of the work pieces to be contacted with an abrading material with less application of force. 
     The flexible substrate  188  includes an opening  192  along with four slits  194 . Thus, the flexible substrate  192  is less rigid than the flexible substrate  186 . The flexible substrate  188  is thus configured for use on contoured surfaces with radii of curvature smaller than those associated with the flexible substrate  186 . Alternatively, using the flexible substrate  188  on work pieces having larger radii of curvature allows for more surface area of the work pieces to be contacted with an abrading material with less application of force. Additional flexible substrates with different patterns may be included in the kit  180 . In alternative embodiments, each flexible substrate is provided with a dedicated base. 
     Different operating characteristics may also be provided by modifying the mismatch between the working length and the base length of different contour abrading devices. Specifically, as the mismatch between the working length and the base length increases, less force is required to conform the respective contour abrading devices to abrade a give surface area of a work piece. By way of example, the kit  200  of  FIG. 10  includes a base  202  and three removable flexible substrates  204 ,  206 , and  208 . In this embodiment, each of the flexible substrates  204 ,  206 , and  208  is provided with an abrading pad or sheet  210 ,  212 , and  214 , respectively. 
     Each of the flexible substrates  204 ,  206 , and  208  provide a different rigidity. The flexible substrate  204  has the shortest working length and is the most rigid of the three substrates. The flexible substrate  206  has a working length that is longer than the working length of the flexible substrate  204 . Accordingly, the flexible substrate  206  is less rigid than the flexible substrate  204  when attached to the base  202 . The flexible substrate  208  has the longest working length of the three substrates. Thus, the flexible substrate  208  is less rigid than the flexible substrate  206  when attached to the base  202 . Additional flexible substrates with different working lengths may be included in the kit  200 . 
     The kit  220  shown in  FIG. 11  is a further embodiment. The kit  220  includes a base  222  and three removable flexible substrates  224 ,  226 , and  228 . In this embodiment, each of the flexible substrates  224 ,  226 , and  228  is provided with a coupling feature such as a hook and loop coupling member  230 ,  232 , and  234 , respectively. The hook and loop coupling members  230 ,  232 , and  234  are used to couple with one of a plurality of abrasive sheets  236  provided with the kit  220 . 
     Each of the flexible substrates  224 ,  226 , and  228  provide a different rigidity. The flexible substrates  224 ,  226 , and  228  each have the same length and width. The difference in flexibility is achieved by forming each of the flexible substrates  224 ,  226 , and  228  from a material that has a hardness different from the material used to form each of the other substrates. Accordingly, the flexible substrate  224  is less rigid than the flexible substrate  226 , which is in turn less rigid than the flexible substrate  228 . 
     The kit  240  shown in  FIG. 12  is a further embodiment. The kit  240  includes a base  242  and three removable flexible substrates  244 ,  246 , and  248 . in this embodiment, each of the flexible substrates  244 ,  246 , and  248  is provided with an abrasive sheet  250 ,  252 , and  254 , respectively. 
     Each of the flexible substrates  244 ,  246 , and  248  provide a different rigidity. The flexible substrates  244 ,  246 , and  248  each have the same length and width. Additionally, the flexible substrates  244 ,  246 , and  248  are formed from the same material. The difference in flexibility is achieved by forming each of the flexible substrates  224 ,  226 , and  228  with a thickness different from the thickness of each of the other substrates. Accordingly, the flexible substrate  244  is less rigid than the flexible substrate  246 , which is in turn less rigid than the flexible substrate  248 . 
     While the present invention has been illustrated by the description of exemplary processes and system components, and while the various processes and components have been described in considerable detail, applicant does not intend to restrict or in any limit the scope of the appended claims to such detail. Additional advantages and modifications will also readily appear to those skilled in the art. The invention in its broadest aspects is therefore not limited to the specific details, implementations, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.