Patent Publication Number: US-9833872-B2

Title: Adjustable contour sander attachment for a power tool

Description:
PRIORITY CLAIM 
     This application is a utility filing from and claims priority to co-pending U.S. Provisional Application No. 62/097,731, filed on Dec. 30, 2014, the entire disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to sanding devices and more particularly to an adjustable contour sanding attachment for a power tool. 
     BACKGROUND 
     There are a number sanding devices available for a user to sand or work a contoured surface. One simple sanding device that can be used to sand a contoured surface includes a body with at least one deformable member that supports a segment of sandpaper. When the user presses this sanding device onto the contoured surface, the deformable member deforms to approximate the shape of the contoured surface as the device is moved over the surface. One problem with manual contour sanders that use a deformable member is that it is difficult to ensure even pressure across the sanding surface because the contoured surface will compress different portions of the deformable member more than other portions. Another problem with manual contour sanders generally is that the user may become fatigued if the contoured surface extends for a considerable length. For example, the profile in a wall molding in a room of a typical residential home may have a height that extends for only a few inches, but the length of the profile along sequential moldings on multiple walls in the room may extend for fifty feet or more. 
     Many types of power tools have been adapted to facilitate sanding of different types of surfaces. For example, belt sanders and orbital sanders are common power sanding devices used in various industries for sanding surfaces. An oscillating power tool is another type of power tool that is well adapted for sanding. An oscillating power tool generally includes a motor and a driving shaft driven by the motor. The driving shaft moves in an oscillatory manner. A working tool with a sanding edge can be attached to the driving shaft and can move with the driving shaft to sand a workpiece surface. Oscillating power tools work well for sanding since they are not too aggressive and are generally able to sand small details in the surface due to the small stroke of the working tool. 
     Some existing oscillating power tools offer multiple tool attachments for sanding contoured surfaces. These tool attachments generally have generic shape profiles pre-formed into the respective working edges of the tool attachments to facilitate sanding the contoured surface. In some cases, the tool attachments are used directly on the contoured surface. In other cases, the tool attachment supports a segment of sandpaper that moved over the contoured surface. In order to sand an existing contour in a surface, the user selects the tool attachment with a shape profile that most closely approximates the shape of the surface and then sands the surface with the selected tool attachment secured to the oscillating tool. One issue with selecting a tool attachment with a generic shape profile is that the tool attachment rarely matches the actual profile of the surface. When the user sands the surface with a tool attachment profile that does not match the surface contour, the sanding damages the surface and/or multiple passes are required to achieve the desired profile in the surface. Another issue with the sander attachments of existing oscillating power tools is that a significant number of individual attachments are needed to cover the wide variety of shapes and sizes of surface contours. 
     What is needed, therefore, is an accessory for a power tool that enables the user to quickly adjust a profile of the accessory to match the contour of a surface to be worked. 
     SUMMARY 
     An adjustable contour sander is provided for a power tool having a drive element capable of reciprocating or oscillatory motion. The accessory includes a mounting plate including a mounting portion configured for engagement to the drive element of the power tool, and a support portion connected to the mounting plate, the support portion defining a support surface. The accessory is further provided with two or more planar members sized to be stacked on the support surface and clamped onto the support portion of the mounting plate by a clamp assembly. The planar members are configured for relative sliding in a longitudinal direction so that the working edges of the planar members conform to the contour of the surface to be sanded. The clamp assembly is configured in a released position to allow the longitudinal movement and in a clamped position to clamp the accessory together for use in sanding the contoured surface. 
     In one aspect, the mounting portion is planar and defines a first plane, and the support portion is planar and defines a second plane offset from the first plane. The support portion may include opposite upturned tabs defining a lateral space therebetween that is sized for a close running fit with the planar members stacked therebetween. 
     In another feature, each of the two or more planar members defines an elongated opening aligned with the longitudinal direction when the planar members are stacked on the support portion. The clamp assembly includes a clamp member configured to extend through the elongated opening of each of the two or more planar members and is engageable to the support 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a side perspective exploded view of an adjustable contour sander attachment for a power tool; 
         FIG. 1A  shows an enlarged view of a planar member of the adjustable contour sander attachment of  FIG. 1 ; 
         FIG. 2  shows a side perspective view of the adjustable contour sander attachment of  FIG. 1 ; 
         FIG. 3  depicts a side perspective view of the adjustable contour sander attachment of  FIG. 1  engaging a contoured surface; and 
         FIG. 4  shows a side schematic view of the adjustable contour sander attachment and the surface of  FIG. 3 ; 
         FIG. 5  depicts a perspective view of a prior art oscillating tool including an accessory tool; 
         FIG. 6  shows a partial view of the prior art oscillating tool and accessory tool of  FIG. 5  showing the nose portion of the oscillating tool; and 
         FIG. 7  depicts a bottom perspective view of the oscillating tool of  FIG. 5  illustrating a mounting interface between oscillating tool and the accessory tool. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the disclosure is thereby intended. It is further understood that the disclosure includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the disclosure as would normally occur to one of ordinary skill in the art to which this disclosure pertains. 
     Embodiments of the disclosure are directed to an accessory tool for use with hand held power tools of the type which have an output shaft that moves in an oscillating manner, such as through a small arc of approximately 2-7° at a high frequency that can extend from less than 10000 oscillations per minute to more than 20000 oscillations per minute. Exemplary tools are marketed by Robert Bosch LLC under the Dremel® brand as the Multi-Max™ oscillating tool and such a tool is shown in the drawings of the disclosure. It should be understood that the accessory tool, while particularly designed and configured for use with this type of tool, can be configured for use with other types and brands of power tools, if desired. 
       FIG. 5  and  FIG. 6  depict an oscillating power tool  10  having elements pertinent to the disclosure. The oscillating tool  10  is configured to drive at least one accessory tool  12  to operate on a variety of materials including, but not limited to, wood, laminate, steel, aluminum, copper, vinyl, carpet, caulk, adhesive, stone, cement, and grout. The oscillating tool  10  includes a generally cylindrically shaped housing  22  constructed of a rigid material such as plastic, metal, or composite materials such as a fiber reinforced polymer. The housing  22  includes a nose portion  24  and a handle portion  26 . The handle portion  26  encloses a motor (not shown). In one embodiment, the motor includes an electric motor configured to receive power from a rechargeable battery  28  connected at the base of the handle portion  26 . In other embodiments, electric power for the motor is received from an AC outlet via a power cord (not shown). As an alternative to electric power, the oscillating power tool  10  is pneumatically or hydraulically powered. Power to the motor is controlled by a power switch  30  provided on the handle portion  26  of the housing  22 . 
     Referring to  FIG. 6 , the housing  22  of the oscillating tool  10  defines a longitudinal axis L. An oscillating drive member (not shown) extends generally perpendicularly with respect to the longitudinal axis L. The motor can be configured to oscillate the drive member about an axis M at high frequencies, e.g., 5,000 to 25,000 oscillations per minute, with a small oscillating angle, typically in a range of between 0.5° and 7°. The drive member supports an accessory tool holder  36  exterior to the housing  24 . The tool holder  36  is configured to releasably secure various accessory tools to the drive member, such as the accessory tool  12 . As the tool holder  36  is oscillated by the drive member, the accessory tool  12  is driven to oscillate about the axis M. 
     To enable a secure connection between the tool holder  36  of the oscillating tool  10  and accessory tools for use with the oscillating tool, the tool holder  36  and associated accessory tools are provided with complementary drive structures  38 ,  40  ( FIG. 7 ) that mate to secure the accessory tool  12  to the tool holder  36 . In the embodiments described herein, the tool holder  36  includes a tool drive structure  38  that has a plurality of protrusions  42  arranged in a circular pattern about a central bore  44 . 
     Accessory tools for use with the power tool  10 , such as the accessory tool  12 , include an accessory drive structure  40  ( FIG. 7 ) that is configured to mate or interlock with the tool drive structure  38  of the tool holder  36 . As depicted in  FIG. 7 , the accessory drive structure  40  of the accessory tool  12  includes a plurality of openings or recesses  46  and a central opening  48  that are sized, shaped, and positioned complementary to the protrusions  42  and central bore  44 , respectively, of the tool drive structure  38 . When the accessory tool  12  is placed onto the tool holder  36 , the protruding features  42  of the tool drive structure  38  are received in the corresponding openings and/or recesses  46  defined in the accessory drive structure  40 . 
     A clamping member  50  ( FIG. 6 ), such as a clamping screw, is used to press the accessory drive structure  40  of the accessory tool  12  into interlocking engagement with the tool drive structure  38  thereby securing the accessory tool  12  to the tool holder  36 . The interlocked drive structures  38 ,  40  enable the oscillating movement of the tool holder  36  to be imparted to the accessory tool  12 . As depicted in  FIG. 7 , a mounting portion  52  defines a slot  49  that extends from a central opening  48  through the outer periphery of the mounting portion  52 . The slot  49  enables the mounting portion  52  to be installed and removed from the tool holder  36  without having to completely remove the clamping screw  50 . 
       FIGS. 1-4  illustrate an accessory  100  for a power tool, such as the oscillating power tool  10  ( FIG. 5  and  FIG. 6 ) that is used to sand a contour  200  in a surface  202  ( FIG. 3 ). The accessory tool  100  includes a mounting plate  102 , a clamp assembly  104 , and a plurality of planar members  106   x . The mounting plate  102  in the embodiment shown includes a generally planar body including a mounting portion  108  that attaches to the power tool  10  and a supporting portion  110  that supports and partially encloses the planar members  106   x . The planar body is formed by stamping and bending one or more metal plates made of hard metal materials, such as carbon and alloy steel or stainless steel. In the embodiment of  FIGS. 1-4 , the mounting plate  102  can have a one-piece construction in which the mounting portion  108  and the supporting portion  110  are integrally formed by stamping and bending a single metal plate. Alternatively, the mounting plate  102  in other embodiments has a two-piece configuration in which the mounting portion  108  is formed from a first plate and the supporting portion  110  is provided as a second plate that is secured to the first plate. 
     The mounting portion  108  has a generally flat disc-like shape that defines a central opening  112 . Although not shown in the embodiment of  FIGS. 1-4 , the mounting portion  108  includes a drive structure that mates with a complimentary drive structure on the tool holder  36  to secure the mounting plate  102  to the oscillating tool  10 . In some embodiments, the mounting portion  108  defines an accessory drive structure (similar to the drive structure  40  in  FIG. 7 ) that includes a slot (similar to slot  49  in  FIG. 7 ) and surrounding openings (similar to openings  46  in  FIG. 7 ) for attachment to the power tool  10 . The accessory drive structure is secured to the tool holder  36  with the mounting portion  108  and the supporting portion  110  arranged substantially perpendicular to the axis M of the drive member as depicted in  FIG. 6 . The mounting portion  108  thus oscillates substantially in a first plane, or oscillation plane, that is perpendicular to the axis M of the drive member. 
     The mounting plate  102  includes an interface portion  114  that is interposed between the mounting portion  108  and the supporting portion  110 . The interface portion  114  extends generally forwardly and downwardly from the mounting portion  108  to the supporting portion  110  in order to offset the supporting portion  110  from the mounting portion  108  and provide clearance for the tool holder  36  and the clamping screw  50  ( FIG. 6 ) during use near a floor surface. The interface portion  114  includes a first angled, or bent, portion  116  located between the mounting portion  108  and interface portion  114 , and a second angled, or bent, portion  118  that is located proximate the supporting portion  110 . In the embodiment of  FIGS. 1-4 , the interface portion  114  transitions into the supporting portion  110  at the second bent portion  118 . The mounting portion  108  of the mounting plate thus defines a first plane and the support portion  110  defines a second plane that is offset from the first plane by the interface portion  114 . 
     Although not shown in the embodiment of  FIGS. 1-4 , gussets may be provided in one or more of the first bent portion  116  and the second bent portion  118  of the interface portion  114  for strengthening the bends against further bending. In one embodiment, the gussets comprise ribs formed by pressing the bends from the outside to form protrusions in the inside corners of the bends (similar to gusset  62  in  FIG. 6 ). 
     The supporting portion  110  of the mounting plate  102  is in the form of a plate that extends from the interface portion  114  in a forward direction generally parallel to the oscillation plane defined by the mounting portion  108 . The supporting portion  110  includes a first lateral edge portion  120 , a second lateral edge portion  121 , and a forward edge portion  122 . The first lateral edge portion  120  and the second lateral edge portion  121  are arranged generally parallel to each other on opposing sides of the supporting portion  110 . As best shown in  FIG. 1 , the forward edge portion  122  can be arcuate, exhibiting a curvature that forms a slight radius from an origin located at the center of the central opening  112 . 
     The supporting portion  110  also includes a first lateral tab  124  and a second lateral tab  126  that are arranged generally parallel to each other and upturned on opposing sides of the supporting portion  100  in order to restrain the planar members  106   x  in a lateral direction (arrow  144  in  FIG. 1 ) on the mounting plate  102  while permitting relative sliding in the longitudinal direction  142 . The first lateral tab  124  extends upwardly from the supporting portion  110  along a portion of the first lateral edge  120  and the second lateral tab  126  extends upwardly from the supporting portion  110  along a portion of the second lateral edge  121 . In the embodiment of  FIGS. 1-4 , the first lateral tab  124  and the second lateral tab  126  extend approximately perpendicularly from the supporting portion  110 . In other embodiments, one or more of the first lateral tab  124  and the second lateral tab  126  can extend from the supporting surface at an angle greater or lesser than 90 degrees. The tabs  124 ,  126  may define a width therebetween that is sized for a close running fit with side edges  130 ,  134  of the planar members that allows the planar members to slide freely in the longitudinal direction while restraining lateral movement or pivoting of the planar members relative to each other and to the mounting plate. 
     Referring now to  FIG. 1A , an enlarged view of one of the planar members  106   x  of  FIG. 1  is shown for purposes of describing the structure of each of the planar members  106   x . For simplicity, the subscript “ x ” has been used following the reference numerals denoting the features of the planar members  106   x  since the features of each of the planar members in the embodiment shown are generally identical. The planar members  106   x  each have an upper surface  128   x , a lower surface  130   x , a first lateral edge  132   x , a second lateral edge  134   x , a back edge  136   x , and an outer working edge  138   x . In the embodiment shown, the lower surface  130   x  is opposed to the upper surface  128   x , the second lateral edge  134   x  is parallel and opposed to the first lateral edge  132   x , and the outer working edge  138   x  is opposed to the back edge  136   x . The working edge  138   x  in some embodiments is parallel to the lateral back edge  136   x . The working edge  138   x  in other embodiments, such as the embodiment shown in  FIGS. 1-4 , can be arcuate, exhibiting a curvature that forms a radius from an origin at the center of the central opening  112  when the planar members  106   x  are secured in at least one position on the mounting plate  102 . Moreover, the working edges  138   x  may be rounded along the edge or between the edges and the surfaces of the planar members. 
     The planar members  106   x  in one embodiment have a uniform width between the first  132   x  and second  134   x  lateral edges so as to enable the first  124  and second  126  lateral tabs of the mounting plate  102  to align the planar members  106   x  in the lateral direction  144 . The planar members  106   x  also each have an elongated slot  140   x  opening to the upper  128   x  and lower  130   x  surfaces and extending generally in a longitudinal direction (arrow  142  in  FIG. 1 ) along the center of the planar member  106   x . It can be appreciated that the first and second lateral tabs  124 ,  126  may be incorporated into the planar members  106   x  to contact the lateral edges of adjacent planar members and the lateral edges of the mounting plate  102 . 
     Referring again to  FIGS. 1-4 , the planar members  106   x  are arranged on the supporting portion  110  in a stack of planar members with the respective upper  128   x  and lower  130   x  surfaces of adjacent planar members  106   x  positioned in slidable contact with one another. In the embodiment shown, a first planar member  106   1  is arranged adjacent to the supporting portion with the lower surface  130   1  of the first planar member  106   1  in slidable contact with an upper surface of the supporting portion  110 . A second planar member  106   2  is arranged adjacent to the first planar member  106   1  with the lower surface  130   2  of the second planar member  106   2  in slidable contact with the upper surface  128   1  of the first planar member  106   1 . A third planar member  106   3  is arranged adjacent to the second planar member  106   2  with the lower surface  130   3  of the third planar member  106   3  in slidable contact with the upper surface  128   2  of the second planar member  106   2 . A fourth planar member  106   4  is arranged adjacent to the third planar member  106   3  with the lower surface  130   4  of the fourth planar member  106   4  in slidable contact with upper surface  128   3  of the third planar member  106   3 . In other embodiments, the accessory  100  can include a greater or lesser number of stacked planar members  106   x  on the mounting plate  102 . 
     The planar members  106   x  are formed from any material that enables the working edges  138   x  of the planar members  106   x  to support sandpaper during a sanding operation with the power tool  10 . Although the planar members  106   x  are shown as being substantially identical to one another, the planar members  106   x  in other embodiments have different geometries. For instance, in some embodiments, a thickness of the second planar member  106   2  between its upper  128   2  and lower  130   2  surfaces is greater than a thickness of the third planar member  106   3 . In other embodiments, the working edges  138   x  of the planar members  106   x  have respective profiles that differ from one another when viewed in a plane perpendicular to the upper surfaces  128   x  of the planar members  106   x  and aligned along the longitudinal direction  142 . 
     The clamping assembly  104  includes a clamp plate  146  and a clamp member  148 , which in the illustrate embodiment is a screw. The clamp plate  146  is positioned adjacent to the upper surface  128   x  of the uppermost planar member  106   x , which in the embodiment of  FIGS. 1-4 , is the fourth planar member  106   4 . The clamp plate  146  has an opening  150  through which the clamp member or screw  148  is inserted and passes through the respective elongated slots  140   x  of each of the planar members  106   x . The supporting portion  110  of the mounting plate  102  may have a threaded opening  152  into which the clamp screw  148  is engageable to secure the planar members  106   x  between the clamp plate  146  and the supporting portion  110 . Alternatively, the clamp screw  148  may engage a threaded nut (not shown) or a nested screw (not shown) in a conventional manner. The clamp plate  146  in the embodiment shown covers a portion of the upper surface  128   x  of the fourth planar member  106   4 . In other embodiments, the clamp plate  146  can cover more or less of the upper surface  128   x  of the uppermost planar member  106   x . 
     In one embodiment, the clamp plate  146  and the first  124  and second  126  lateral tabs are sized such that at least a portion of the first and second lateral tabs extends above the upper surface  128   x  of the uppermost planar member  106   x  and the clamp plate  146  is positionable between the first and second lateral tabs. The accessory  100  in some embodiments includes a kit that includes two or more clamp screws  148   x  that have different lengths to accommodate different numbers of stacked planar members  106   x  on the mounting plate  102 . For instance, a first clamp screw  148   1  in one embodiment has a first length sized to secure four planar members  106   x  under the clamp plate  146  while a second clamp screw  148   2  has a second length that is longer than the first length to secure five planar members  106   x  under the clamp plate  146 . 
     The clamp assembly  104  is adjustable between a released position in which the planar members  106   x  are each movable along the supporting portion  110  in the longitudinal direction  142  and a clamped position in which the planar members  106   x  are fixed in position on the supporting portion  110 . With the clamp assembly  104  in the released position, the planar members  106   x  are each moveable relative to the supporting portion  110  such that the respective working edges  138   x  of the planar members  106   x  are positionable at different offsets from the forward edge portion  122  of the supporting portion  110 . With the clamp assembly  104  in the clamped position, the respective working edges  138   x  of the planar members  106   x  are fixed relative to the forward edge portion  122  and to each other. In the embodiment illustrated in  FIGS. 1-3 , the clamp assembly  104  incorporates a threaded screw for fixing and clamping the plates together. Alternatively, the clamp assembly may incorporate some form of quick-release or cam mechanism to simply the clamping process. 
     The planar members  106   x  are shown in the figures with generally smooth upper and lower surfaces so that the planar members can slide freely in the longitudinal direction  142  relative to each other and to the mounting plate  102 . Alternatively, the surfaces of the planar members may be provided with a surface feature that resists relative movement between planar members when the clamp assembly is in its clamped position. The surface feature is configured to allow the planar members to achieve essentially unlimited positions relative to each other or to achieve at least infinitesimal gradations of relative movement. In one example, each planar member  106   x  may be provided with a surface roughness coating on at least one surface of the member. 
     A method for using the accessory  100  is discussed with reference to  FIG. 3  and  FIG. 4 . A user identifies a contour  200  in a surface  202  to be sanded by the power tool  10 . The user can select the number of planar members to be stacked on the mounting plate that is sufficient to complement the contour  200 . A segment of sandpaper  154  can be affixed to the accessory  100  in a suitable manner, such as by fixing along the respective working edges  138   x  of the selected planar members  106   x . In some embodiments, the sandpaper  154  may be mechanically fastened to the accessory between the supporting portion  110  of the mounting plate  102  and the clamp assembly  104 . The sandpaper  154  in other embodiments may include an adhesive backing that adheres to the working edges  138   x  and/or the surfaces of the planar members  106   x  or of the mounting plate supporting portion  110  and/or clamp plate  146 . The sandpaper  146  may be further provided with an opening, similar to the opening  140  in the planar members, to receive the clamp screw  148  therethrough. 
     The clamp assembly  104  of the accessory  100  is then adjusted to the released position such that the planar members  106   x  are adjustable relative to the forward edge portion  122  of the mounting plate  102 . With the clamp assembly  104  in the released position, the planar members  106   x  with the affixed sandpaper  154  are still restrained in the longitudinal direction  142  (by the screw  148  extending through the slots  140 ) so that the planar members and the sandpaper can be moved into contact with the contour  200  until the respective working edges  138   x  of the planar member  106   x  take the shape of the contour  200 . It can be appreciated that the planar embers are sized in the longitudinal direction so that the working ends  138  all extend beyond the end  122  of the mounting plate. Moreover, the slots  140  in the planar members  106   x  have a length sufficient to allow the combined working edges of the stacked planar members to form a wide range of contour shapes and depths. In one embodiment, the slots  140  may have a length of about one inch. 
     Once the planar members  106   x  take the shape of the contour  200 , the clamp assembly  104  is adjusted to the clamped position to fix the working edges  138   x  of the planar members  106   x  relative to the forward edge portion  122  of the mounting plate  102 . The user then ensures that the sandpaper is snug against the working edges  138   x  of the planar members  106   x . The mounting portion  108  of the mounting plate  102  can be mounted onto the tool holder  36  of the power tool  10  so that the user can operate the power tool  10  to sand the contour  200  in the surface  202 . 
     While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the disclosure are desired to be protected.