Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 60/692,906 filed Jun. 22, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to pencil sharpeners. More particularly, this invention relates to pencil sharpeners which are automatically actuated to sharpen a pencil.  
       SUMMARY OF THE INVENTION  
       [0003]     Briefly stated, the invention in a preferred form is a pencil sharpener which comprises a base having a bottom surface adapted for being supported by a horizontal surface. A cutting assembly is mounted to the base and projects upwardly therefrom. A cage is disposed above the base and has an upper portion surrounding the cutting assembly. The upper portion of the cage includes at least one radial chute. An upper cover portion has an opening for insertion of an end of a pencil. A receptacle disposed above the base surrounds the cage, for collecting the shavings from sharpening a pencil.  
         [0004]     The receptacle is vertically displaceable from the base for discarding the shavings. Alternatively, a cover disposed over the top of the receptacle may be removed for discarding the shavings.  
         [0005]     The receptacle comprises an outer wall, an inner wall and an annular floor panel extending radially between the outer and inner walls. The inner wall extending axially only a portion of the axial extent of the outer wall. Preferably, the inner and outer walls are substantially cylindrical and are composed of transparent material.  
         [0006]     The cage also has a lower portion disposed within said inner wall of said receptacle. The outer surface of the cage lower portion and the inner surface of the receptacle inner wall form a seal preventing the shavings from falling between the receptacle and the cage.  
         [0007]     The pencil sharpener may further comprise a safety switch operable by the receptacle for preventing operation of the cutting assembly when the receptacle is not seated on the base. The safety switch includes an activator that is biased to extend upwardly from an upper rim of the base, the activator being pressed down against the biasing force when the receptacle is positioned on the base. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which:  
         [0009]      FIG. 1  is a perspective view of a pencil sharpener in accordance with the present invention;  
         [0010]      FIG. 2  is an exploded view of the pencil sharpener of  FIG. 1 ;  
         [0011]      FIG. 3  is an enlarged view of the receptacle and cover of  FIG. 2 ;  
         [0012]      FIG. 4  is a cross-sectional view of the receptacle and cover of  FIG. 3 ; and  
         [0013]      FIG. 5  is a top view of the receptacle and cover of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]     With reference to the drawings wherein like numerals represent like parts throughout the several figures, a pencil sharpener in accordance with the present invention is generally designated by the numeral  10 . Pencil sharpener  10  is an automatic pencil sharpener which may be powered by an external power supply or an internal battery. The pencil sharpener is adapted to be positioned on a desk top in an upright orientation for use as needed.  
         [0015]     The pencil sharpener includes a base  20  which houses a motor (not illustrated). The top of the base is defined by an annular rim  22 . A cutting assembly  24  is supported above the base  20 . The motor provides, through a gear assembly, dual rotary movement for an obliquely oriented multi-helical cutting blade  30  of the cutting assembly  24 . The blade  30  is preferably a titanium bonded blade.  
         [0016]     A cage  40  is mounted above the base  20  and covers the blade  30 . The cage  40  includes an end cap  42  which defines an opening  44  for insertion of the end of the pencil. An upper portion  45  of the cage  40  includes a plurality of equiangularly spaced openings which form chutes  46 . The floor  48  of each chute  46  extends radially downward to facilitate transport of pencil shavings from the vicinity of the cutting blade  30  to a holding container  51  of the receptacle  50 .  
         [0017]     The receptacle  50  surrounds the cage  40  and sits upright on the upper rim  22  of the base  20 . The receptacle  50  has a tapered quasi-annular cover  58  which is removable from the receptacle as illustrated in  FIG. 2 . The inner periphery  60  of the cover  58  is complementary with the outer periphery  62  of the end cap  42 . The receptacle  50  includes a substantially cylindrical outer wall  52 , a coaxial substantially cylindrical inner wall  54  which surrounds a lower portion  47  of the cage  40 , and an annular floor panel  56  extends radially between the bottoms of the outer and inner walls  52 ,  54 . The inner and outer walls  54 ,  52 , and the floor panel  56  form the vertically extending holding container  51  for retaining the pencil shavings.  
         [0018]     It should be appreciated that the pencil sharpener  10  preferably has an aesthetically pleasing appearance. It should also be appreciated that the cylindrical shape of the inner and outer walls  54 ,  52  efficiently maximize the volume of the holding container  51 , thereby maximizing the time that the pencil sharpener  10  may be used before the holding container  51  must be emptied. Further, a combination of the equiangularly spaced openings which form chutes  46  and the rotary motion of blade  30  causes the pencil shavings to be distributed uniformly around the periphery of the cage  40  and into the holding container  51 . Preferably, at least the outer wall  52  of the receptacle  50  is composed of transparent material, allowing the user(s) to easily determine when the holding container  51  must be emptied.  
         [0019]     In operation the end of a pencil to be sharpened is inserted from above the pencil sharpener  10  downwardly through the opening  44  between two feed rollers (not shown) of the cutting assembly  24 . Contact of the end portion of the pencil with an activation switch (not shown) of the cutting assembly  24  automatically starts the motor which 1) turns the feed rollers in the infeed direction to pull the end portion of the pencil into the cutting assembly  24  and 2) turns the blade  30  in a first, sharpening direction to sharpen the pencil tip. The shavings removed during the sharpening operation are forced outwardly through the chutes  46  for downward collection in the holding container  51  of the receptacle  50  under the centrifugal rotary motion of the blade  30  and the force of gravity. When the cutting assembly  24  senses that the pencil tip has completed sharpening, the sharpener controller reverses the motor which 1) turns the blade  30  in the opposite direction to the sharpening direction and 2) turns the feed rollers in the outfeed direction to retract the end portion of the pencil out of the cutting assembly  24 . When the end portion of the pencil has retracted such that the pencil is no longer in contact with the activation switch, the sharpener controller stops the motor.  
         [0020]     The shavings retained in the holding container of the receptacle  50  may be removed by upwardly displacing the receptacle  50  from the base  20 , thereby withdrawing the cage lower portion  47  from the opening  64  formed by the inner wall  54 , and removing the receptacle  50  from the sharpener  10 . The cover  58  may be removed to facilitate emptying the holding container  51  or the shavings may simply be removed through the central opening  66  of the cover  58 . After the shavings have been discarded, the receptacle  50  is placed back into position on the base  20 . Alternatively, the entire pencil sharpener  10  may be transported to a waste receptacle, the cover  58  removed, and the pencil sharpener  10  upended over the waste receptacle to discard the shavings. The cover  58  is then replaced and the pencil sharpener  10  returned to its work station for use.  
         [0021]     The outer diameter of the cage lower portion  47  and the inside diameter of the inner wall  54  are selected to provide either a minimal clearance or a frictional fit between the cage lower portion  47  and the inner wall  54 , to seal the gap between the receptacle  50  and the cage  40  and prevent shavings from falling between the receptacle  50  and the cage  40 .  
         [0022]     The control system for the sharpener  10  may include a safety switch  68  that prevents operation of the cutting assembly  24  when the receptacle  50  is not seated properly on the base  20 . Preferably, the activator for safety switch  68  is spring biased to extend upwardly from the upper rim  22  of the base  20 , and is pressed down against the biasing force by the inner wall  54 , the outer wall  52 , or the floor panel  56  when the receptacle  50  is positioned properly on the base  20 . If the receptacle  50  is removed or raised above the base  20 , safety switch  68  opens either the motor control circuit or the motor power circuit to prevent activation of the motor. If the receptacle  50  is properly positioned on the base  20 , safety switch  68  closes, allowing the motor to be activated when a pencil is inserted into the cutting assembly  24 . Accordingly, the outer wall  52  of the receptacle  50  precludes access to the cutting blade  30  though the chutes  46  whenever the motor may be activated.  
         [0023]     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

Technology Category: 7