Patent Publication Number: US-7904989-B1

Title: Rotary eraser assembly

Description:
BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to a rotary eraser assembly for erasing residue of glue. 
     2. Related Prior Art 
     Glue is often used to attach various decorations to various things such as the doors of vehicles. Glue is used to attach sunshades to the windows of vehicles. The glue ensures the firm attachment of the decorations or sunshades to the doors or windows. Sometimes, a decoration or sunshade is peeled from a door or window. Sometimes, it is intended to replace a decoration or sunshade with a new one. In these cases, there is residue of glue on the door or window. 
     Chemicals can be used to clean the door or window of the residue of glue. It is however difficult. Worse, the chemicals might damage the door or window. 
     There are various rotary eraser assemblies for erasing the residue of glue from the door or window. Such a rotary eraser assembly includes an axle, a rotary eraser provided on the axle, two discs provided on the axle so that the rotary eraser is located between the discs and tabs for fastening the rotary eraser to the discs. 
     As disclosed in Taiwanese Patent M272624, a rotary eraser assembly includes two discs 20 and a rotary eraser 10 provided around the discs 20 by injection molding. That is, the discs 20 are embedded in the rotary eraser 10. The discs will not be broken when they are subjected to a huge torque needed for driving the rotary eraser 10. The discs 20 however have to be disposed of together with the rotary eraser 10 when only the later is consumed and has to be replaced with a new one. This is a waste. 
     As disclosed in Taiwanese Patent M291870, a rotary eraser assembly includes a rotary eraser 16 and two discs 14 and 15. The rotary eraser 16 is sandwiched between the discs 14 and 15 and formed with slots 18 for receiving tabs extended from the discs 14 and 15. The tabs could however be broken when they are subjected to a huge torque needed for driving the rotary eraser 16. 
     As disclosed in Taiwanese Patent Publication No. 364416, a rotary eraser assembly includes a rotary eraser 16 and two discs 14 and 15. The rotary eraser 16 is sandwiched between the discs 14 and 15 and formed with slots 18 for receiving tabs extended from the discs 14 and 15. The tabs could however be broken when they are subjected to a huge torque needed for driving the rotary eraser 16. 
     As disclosed in Taiwanese Patent Publication No. 399506, a rotary eraser assembly includes a rotary eraser 22 and two discs 14 and 19. The rotary eraser 22 is sandwiched between the discs 14 and 19. The disc 14 is formed with three tabs 15 connected to one another. The rotary eraser 22 includes three slots 23 for receiving the tabs 15. The tabs 15 could however be broken when they are subjected to a huge torque needed for driving the rotary eraser 22. 
     The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art. 
     SUMMARY OF INVENTION 
     It is the primary objective of the present invention to provide a reliable rotary eraser assembly. 
     To achieve the primary objective of the present invention, a rotary eraser assembly includes a rotary eraser, two discs, a threaded bolt and a nut. The rotary eraser includes, in each of two opposite sides, a cavity in communication with the aperture and at least one recess in the wall of the cavity. Each of the discs includes an annular lip disposed in the cavity in a related one of the sides of the rotary eraser and at least one block disposed in the recess in the related side of the rotary eraser. The threaded bolt is inserted through the rotary eraser and the discs. The nut is engaged with threaded bolt. 
     Other objectives, advantages and features of the present invention will become apparent from the following description referring to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention will be described via the detailed illustration of three embodiments referring to the drawings. 
         FIG. 1  is an exploded view of a rotary eraser assembly according to the first embodiment of the present invention. 
         FIG. 2  is a perspective view of the rotary eraser assembly shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the rotary eraser assembly shown in  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the rotary eraser assembly taken along a line A-A shown in  FIG. 3 . 
         FIG. 5  is a perspective view of a driving device operatively connected to the rotary eraser assembly shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 through 4 , a rotary eraser assembly includes a rotary eraser  10 , a disc pair  20  for sandwiching the rotary eraser  10 , a threaded bolt  30  inserted through the rotary eraser  10  and the disc pair  20  and a nut  35  engaged with the threaded bolt  30  according to the preferred embodiment of the present invention. The disc pair  20  includes a first disc  21  and a second disc  23 . 
     The rotary eraser  10  is in the form of a wheel. The rotary eraser  10  includes erasing fins  11  on the periphery and an aperture  15  centrally defined therein. The rotary eraser  10  includes two opposite sides each including a shallow cavity  16  therein, a deep cavity  17  between the aperture  15  and the shallow cavity  16  and recesses  18  in the wall of the deep cavity  17 . 
     The first disc  21  includes a hub  22  on a side, an annular lip  25  around the hub  22 , blocks  26  extended from the annular lip  25  in a radial manner and bosses  27  around the annular lip  25 . The hub  22  includes a countersink hole therein. 
     The second disc  23  includes a hub  24  on a side, an annular lip  25  around the hub  24 , blocks  26  extended from the annular lip  25  in a radial manner and bosses  27  around the annular lip  25 . The hub  24  includes an aperture therein. 
     Referring to  FIG. 3 , the first disc  21  is disposed in the shallow cavity  16  in one of the sides of the rotary eraser  10 , the annular lip  25  thereof is disposed in the deep cavity  17 , the blocks  26  thereof are disposed in the recesses  18  and the hub  22  thereof is inserted in the aperture  15 . 
     Referring to  FIGS. 3 and 4 , the second disc  23  is disposed in the shallow cavity  16  in the other side of the rotary eraser  10 , the annular lip  25  thereof is disposed in the deep cavity  17  and the blocks  26  thereof are disposed in the recesses  18 . 
     The threaded bolt  30  is inserted through the first disc  21 , the rotary eraser  10  and the second disc  23 . The threaded bolt  30  is engaged with the nut  35 . The threaded bolt  30  is formed with an enlarged head disposed in the countersink hole of the hub  22  of the first disc  21 . The nut  35  is abutted against the second disc  23 . Thus, the bosses  27  of the first disc  21  are forced into one of the sides of the rotary eraser  10  while the bosses  27  of the second disc  23  are forced into the other side of the rotary eraser  10 . Therefore, the rotary eraser  10  is firmly sandwiched between the first disc  21  and the second disc  23 . 
     Referring to  FIG. 5 , the rotary eraser assembly is operatively connected to a driving device  50 . The driving device  50  can rotate the rotary eraser assembly to erase residue of glue from an object. 
     The present invention has been described via the detailed illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.