Abstract:
A paper shredder has two rotary cutters driven by a deceleration device and a casing encased the two rotary cutters and the decelerating device and having a paper track defined between the two paper guides and cashing to allow the stuck paper to be directed directly into the can mounted below the two rotary cutters without damaging any mechanism.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention is a paper shredder, and more particularly is a paper shredder having guiding slots defined between first and second paper guides on two rotary cutters so as to eliminate the blockage by the shredded paper. A casing is provided to enclose the motor and the driving mechanism to prevent shredded paper from falling into the motor or the driving mechanism and thus causing a malfunction.  
           [0003]    2. Description of the Related Art  
           [0004]    A conventional paper shredder, as in U.S. Pat. Nos. 5,354,001, 3,724,766, 5,893,524, 4,913,360. When operated, will automatically have the shredded paper fallen into the trash can. However, having the shredded paper fallen into the trash can, the motor of the paper shredder needs to rotate in a reversed direction so as to allow the shredded paper to escape from the rotary cutters to smoothly fall into the trash can, which allows a small amount of shredded paper stuck in the shredder. When the amount of shredded paper increases, the paper shredder will not function normally. Thus a user will have to disassemble the paper shredder to clean the shredded paper to resume the function of the paper shredder. Furthermore, the rotary cutters of the conventional paper shredder are exposed directly to the outside of the shredder, which not only affects the overall appearance, but also easily causes malfunction to the mechanism due to the fallen dust and objects.  
           [0005]    The present invention provides an improved paper shredder to overcome the above mentioned shortcomings.  
         SUMMARY OF THE INVENTION  
         [0006]    The primary objective of the invention is to provide an improved paper shredder to allow the shredded paper to fall into the trash can directly without blockage the function of the mechanism.  
           [0007]    Another objective of the invention is to provide a blocking device in the entry of the paper shredder to prevent any undesired objects from falling into the paper shredder to malfunction any mechanism in the machine.  
           [0008]    Still another objective of the invention is to provide an improved paper shredder having a first and a second paper guides on the two rotary cutters of the paper shredder so as to guide the shredded paper easily.  
           [0009]    Still another objective of the invention is that each of the first and the second paper guides have an identification hole, such that the user is able to quickly and easily assemble the rotary cutters on the paper shredder.  
           [0010]    Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of the main body of the paper shredder constructed in accordance with the present invention;  
         [0012]    [0012]FIG. 2 is a perspective view of the paper shredder of FIG. 1;  
         [0013]    [0013]FIG. 3 is a schematic side view of the paper shredder of the invention;  
         [0014]    [0014]FIG. 4 is a partial enlarged schematic view showing the mounting of a blocking device mounted on top of two rotary cutters of the invention;  
         [0015]    [0015]FIG. 5 is a perspective view of the rotary cutters of the present invention;  
         [0016]    [0016]FIG. 6 is a cross sectional view of the paper guides mounted on the axle; and  
         [0017]    [0017]FIG. 7 is a cross sectional view of the paper guides together with the pads of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    With reference to the figures, a paper shredder or the invention has a top cover  1 , a base  2  and a can  10 .  
         [0019]    The top cover  1  has an entrance  11  defined to allow the entrance of waste paper and a switch  12  mounted to connect with circuits (not shown) to control the operation of the paper shredder.  
         [0020]    The base  2  is provided to securely accommodate a motor  3 , a decelerating device  4 , two rotary cutters  5 ,  6  and two paper guides  7 ,  7 ′.  
         [0021]    The motor  3  is connected with the switch  12  by means of wires such that the switch  12  is able to control the operation of the motor  3 . The motor  3  drives the motion of the decelerating device  4 . In the preferred embodiment of the invention as shown in FIGS. 2 and 3, the shaft of the motor  3  is mated with the shaft  41  of the first gear  41  and the shaft  411  of the first gear  41  is mated with a second gear  42 . The shaft  421  of the second gear  42  is mated with a small gear  43  and the small gear  43  is mated with a big gear  44 . The big gear  44  is then mated with two gears  45 . The two gears  45  are respectively engaged with shafts  51 ,  61  of two rotary cutters  5 ,  6 . In this arrangement, the two rotary cutters  5 ,  6  each have a first and a second blades  52 ,  62  alternately mounted with each other and are driven to rotate by the decelerating device  4 . The two paper guides  7 ,  7 ′ extend out from each of the first and the second blades  52 ,  62 . Each of the paper guides  7 ,  7 ′ correlates with each other in such a manner that when the paper is shredded, both paper guides  7 ,  7 ′ will help to push the shredded paper to a desired direction.  
         [0022]    With reference to FIGS. 2 and 4, the two rotary cutters  5 ,  6  are rotatably mounted in the U-shaped casing  8 . Each of the two rotary cutters  5 ,  6  consists of two secondary cutters  52 ,  62  and every secondary cutter  52 ,  62  has multiple cutting edges  521 ,  621 . A paper track  81  is then defined between the two paper guides  7 ,  7 ′ and cashing  8 . Such that when the volume of the paper to be shredded is too large and the rotary cutters  5 ,  6  are stuck, a reverse rotation of the rotary cutters  5 ,  6  will drive the jammed paper into the paper track  81 . The jammed paper will then still fall into the can  10 . Furthermore, the second paper guide  7 ′ isolates the rotary cutters  5 ,  6  from the decelerating device  4  and the motor  3  so as to avoid malfunction caused by the jammed paper when being driven by the reverse rotation of the rotary cutters  5 ,  6 .  
         [0023]    Referring again to FIGS. 3, 4 and  5 , a tube  71  is respectively mounted under the two rotary cutters  5 ,  6  such that notches  72  of each of the paper guides  7 ,  7 ′ mate with the tube  71  and the paper guides  7 ,  7 ′ are then secured. A washer  73  is respectively secured on the shafts  51 ,  61  of the two rotary cutters  5 ,  6  and has a cutout  731  defined to correspond to an edge  74  of the paper guide  7 ′, as shown in FIGS. 6 and 7.  
         [0024]    It is to be noted that a seat  9  is mounted on top of the casing  8  and having two cylinders  91  closely engaged with each other. The joint between the two cylinders  91  corresponds to the entrance  11  of the top cover  1 . The two cylinders  91  are spring-biased such that when a paper is to be shredded, the user insets the paper into the entrance  11  and the paper will slit through the joint of the two cylinders  91 . With the provision of the two cylinders  91 , dust and alien objects are prevented to fall into the mechanism to cause any damage.  
         [0025]    It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.