Patent Document

CLAIM OF PRIORITY UNDER 35 U.S.C. §119 
     The present application for patent claims priority to Provisional Application No. 61/143,016 entitled “Multi-Drum Sander and/or Rasp” filed Jan. 7, 2009, and assigned to the assignee hereof and hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments of the present invention generally relate to the field of power tools. 
     2. Background 
     In the power tool field, various types of sanding apparatuses such as power drum sanders and power rasps are all known. For example, U.S. Pat. Nos. 4,720,940, 5,842,913, 6,645,054, 5,679,056, 5,947,806, 5,531,636, 5,254,036, 4,560,006, 6,264,553, 4,941,246, 4,685,181, and 5,495,796—the disclosures of which are hereby expressly incorporated within—each disclose examples of conventional sanding apparatuses. However, there currently does not exist a compact, portable, hand-held power sander or power rasp. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
     Described herein is technology for, among other things, a multi-purpose sanding or filing apparatus. The apparatus includes a motor, a plurality of drive mechanisms in mechanical communication with the motor, and a plurality of drums, where each of the drums has an axis passing therethrough, the drums are coupled with respective drive mechanisms, and the drive mechanisms are operable to rotate the drums about their respective axes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of embodiments of the invention: 
         FIG. 1  is an isometric view of a sanding and/or filing apparatus, in accordance with various embodiments of the present invention; 
         FIG. 2  is a side view of a sanding and/or filing apparatus, in accordance with various embodiments of the present invention; 
         FIG. 3  is a top view of a sanding and/or filing apparatus, in accordance with various embodiments of the present invention; 
         FIG. 4  is a front view of a sanding and/or filing apparatus, in accordance with various embodiments of the present invention; 
         FIG. 5  is a side view of a sanding and/or filing apparatus, showing the drums in a convex orientation relative to each other, in accordance with various embodiments of the present invention; 
         FIG. 6  is a side view of a sanding and/or filing apparatus, showing the drums in a concave orientation relative to each other, in accordance with various embodiments of the present invention; 
         FIG. 7  is a perspective view of a drive mechanism for a sanding and/or filing apparatus, in accordance with various embodiments of the present invention; and 
         FIG. 8  is a partially exploded view of a drive mechanism for a sanding and/or filing apparatus, in accordance with various embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the claims. Furthermore, in the detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, and components have not been described in detail as not to unnecessarily obscure aspects of the present invention. 
     Generally speaking, embodiments provide for a single- or variable-speed, portable, handheld sanding apparatus having multiple drums. The drums may include, but are not limited to, sander drums and rasp drums. 
       FIGS. 1-6  illustrate various views of a sanding apparatus  10  in accordance with various embodiments of the present invention. Generally, the sanding apparatus includes a motor housing  24  having a motor disposed therein, a front handle  22 , and a rear handle  20 . The motor is operable to drive a plurality of drive mechanisms. The drive mechanisms are coupleable to a plurality of drums  12 . In one embodiment, the drums  12  are interchangeable so that the sanding apparatus  10  may be converted from a drum sander to a power rasp. 
     In one embodiment, the direction which the drive mechanisms rotate the drums may be switched from clockwise to counter-clockwise, and vise versa. Moreover, each drive mechanism  26  or, alternatively, groups of drive mechanisms  26 , may be switched independently from the other drive mechanisms. Thus it is possible for some of the drums  12  to be rotated in the clockwise direction while others are rotated in the counter-clockwise direction. This is advantageous because torque transmitted from the sanding apparatus  10  to the user is significantly reduced. 
     In one embodiment, each drive mechanism is positioned to the side of the attached drum  12 . In another embodiment, the drive mechanisms  26  may bisect the drums  12 . The drive mechanisms  26  may incorporate solid shafts, a compressible rubber cylinders, pneumatic cylinders, splines, keys, belts and pulleys, or the like. 
     In one embodiment, the drive mechanisms, and thus the drums  12 , may be fixed in a linear orientation relative to each other, such as is depicted in  FIG. 2 . In another embodiment, the drive mechanisms, and thus the drums  12 , may be vertically suspended relative to the main body of the sanding apparatus, so that the drive mechanisms  26  and drums  12  may be adjusted in the vertical direction. In still another embodiment, the drive mechanisms, and thus the drums  12 , may be vertically suspended relative to the main body of the sanding apparatus, so that the drive mechanisms  26  and drums  12  may freely move in the vertical direction in order to dynamically adjust to the contour of a non-planar surface. For example, in  FIG. 5 , the drums  12  have adjusted to a convex orientation so as to conform to a concave surface, while in  FIG. 6 , the drums  12  have adjusted to a concave orientation so as to conform to a convex surface. In yet another embodiment, the drive mechanisms  26  may be switchable between the aforementioned fixed and suspended configurations. 
     The disconnection and attachment of the interchangeable drums  12  may be implemented in a number of ways. For example, the sanding apparatus  10  may include a shaft extending laterally from the drive mechanisms, and each drum  12  may also include a longitudinal through-hole sized and shaped so that the drums  12  can be slid over the shafts and the secured thereto with a nut or other suitable fastener. Alternatively, the rotating shafts may each comprise expanding mandrels, which expand to lock the drums into place upon the insertion of a bolt therein. In still other embodiments, the drums  12  may include a latch, cartridge, or other type of quick-connect mechanism to enable convenient connection to and disconnection from the drive mechanisms. 
       FIGS. 7 and 8  illustrate one possible embodiment of the drive mechanisms that utilizes a belt-and-pulley drive system. It should be appreciated that the embodiment illustrated in  FIGS. 7 and 8  is exemplary, and other embodiments are not so limited. By way of example, and not limitation, the drums  12  could instead be driven using shafts and gears, rather than belts and pulleys. 
     In the illustrated embodiment, each drum  12  is solidly attached to an axle  32 . Each axle slides thru an axle support  33 , which is disposed within a support frame rail  36 . In one embodiment, the axle support  33  is toleranced so as to support the drum  12  from one end. Disposed at one end of the axle  32  is a pulley  34 , which, together with belt  42 , drives the axle  32  and, in turn, the corresponding drum  12 . 
     Each axle support  33  is coupled to the support frame rail  36  via a slide  37 , which permits the height of the drum  12  to be adjusted vertically, while also keeping the associated drum  12  aligned. The sliding support  37  may include a threaded shaft  35  extending vertically therefrom. In one embodiment, turning the threaded shaft will adjust the height of the roller in a manner to a simple screw jack. A lock nut can optionally be used to lock the height of the slider  37 . 
     It should be appreciated that driving the drums  12  can be achieved in a number of ways. For example, the illustrated embodiment of  FIGS. 7 and 8  utilizes a single motor  41  and a multi-pulley belt system. As shown, a flat belt  42  can be woven between the pulleys  34  to thereby engage each of the pulleys  34 . This weaving will cause adjacent rollers to turn in opposite directions. In one embodiment, the drive mechanism may include one or more idler pulleys  38  to ensure the pulleys  34  of one or more end drums have sufficient belt wrap for engagement. 
     In the illustrated embodiment, the drive motor  41  is mounted above the drums  12 , for example, within housing  24 . Spring-loaded idlers  40  may be provided to ensure the belt  42  stays tight as the roller heights are adjusted or as the belt  42  naturally stretches over time. It should be appreciated that other embodiments may utilize multiple motors. 
     Thus, embodiments provide for a multi-drum, hand-held sanding apparatus that may be re-configured into different sanding tools, such as a drum sander and a power rasp. Such an apparatus according to various embodiments would be significantly more portable when compared to conventional sanding apparatuses. Embodiments that employ suspended drums provide added versatility because they can be more effective than conventional sanding apparatuses on non-planar surfaces. Still further, various embodiments are safer and easier to use than conventional sanding apparatuses which use a single drum. 
     The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Technology Category: 7