Abstract:
A portable pencil sharpener is capable of being manually operable or operable to be driven by a remote torque driver. The pencil sharpener is capable of sharpening either a carpenter&#39;s pencil or a Number 2 pencil. Pencil shavings are retained in a compact housing and removed through a retractable panel.

Description:
BACKGROUND 
       [0001]    This disclosure relates generally to hand held mechanical pencil sharpeners. More particularly, this disclosure relates to portable, compact mechanical sharpeners which sharpen a pencil and retain the shavings within a housing. 
       SUMMARY 
       [0002]    Briefly stated, a dual drive mode pencil sharpener comprises a housing defining a central axis and having a first end and an axially spaced second end. A sharpener comprising a blade is mounted in the housing and is rotatable relative to the housing about the central axis. An axial pencil slot is defined in the first end and alignable with the sharpener. A coupler is rotatably fixed with the sharpener and has an engagement interface accessible at the second end. The coupler has a clutch mechanism. In a first mode, the clutch mechanism rotatably fixes the housing with the sharpener, and in a second mode, the clutch mechanism allows the sharpener to be rotatable relative to the housing. 
         [0003]    The axial slot preferably has a geometry which will accommodate a carpenter&#39;s pencil or a No. 2 pencil. In one embodiment, the engagement interface is a hex socket. The housing comprises a retention rim which defines two diametrically disposed detents. The coupler has two opposed axially extending slots. A follower rod projects through and beyond each slot and is receivable in the detents in the first drive mode. A driver insertable into the socket transforms the pencil sharpener to the second drive mode wherein the driver is drivable to rotate the sharpener relative to the housing. 
         [0004]    In one embodiment, a dual drive mode pencil sharpener comprises a housing defining a central axis and having an interior detent and a first end and an axially spaced second end. A sharpener is generally alignable with the slot and comprises a blade rotatable relative to the housing about the axis. The first end has an axial slot. The second end has a second opening. A coupler is rotatably fixed with the sharpener and has an axial socket accessible at the second opening. The coupler has an axially extending slot receiving an axially displaceable, spring-biased rod radially projecting beyond the slot. In a first drive mode, the rod is received in the detent to rotatably fix the housing with the sharpener. In a second drive mode, the rod is displaced from the detents so that the sharpener is rotatable relative to the housing. 
         [0005]    A retractable panel allows for the removal of pencil shavings from the housing. The socket is preferably a hex socket. The housing has an inward retention rim which defines two diametrically disposed detents and has a pair of cam surfaces adjacent each said detent. The coupler has two opposed axially extending slots. The rod projects through each slot and has opposed end portions each receivable in one of the detents. When a driver is insertable into the socket, the pencil sharpener is transformed to the second drive mode and is drivable to rotate the sharpener relative to the housing. The coupler may include a plurality of axially extending radially protruding guides. The rod rotatably follows the retention rim under the bias of a spring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a dual drive pencil sharpener; 
           [0007]      FIG. 2  is a perspective view of the pencil sharpener of  FIG. 1  in a different orientation together with a carpenter&#39;s pencil which has been inserted for sharpening; 
           [0008]      FIG. 3  is a front view of the dual drive pencil sharpener of  FIG. 1 ; 
           [0009]      FIG. 4  is a rear view of the dual drive pencil sharpener of  FIG. 1 ; 
           [0010]      FIG. 5  is a left side view, partly diagrammatic, of the dual drive pencil sharpener of  FIG. 1 ; 
           [0011]      FIG. 6  is an end view of the dual drive pencil sharpener of  FIG. 1 ; 
           [0012]      FIG. 7  is an opposite end view of the dual drive pencil sharpener of  FIG. 1 ; 
           [0013]      FIG. 8  is an exploded view of the dual drive pencil sharpener of  FIG. 1 ; 
           [0014]      FIG. 9  is an exploded view of a portion of the dual drive pencil sharpener of  FIG. 8 ; 
           [0015]      FIG. 10  is a fragmentary exploded view of a portion of the dual drive pencil sharpener illustrated in  FIG. 9 ; 
           [0016]      FIG. 11  is a fragmentary interior perspective view, portions removed, of the pencil sharpener portion of  FIG. 10  upon assembly and illustrated in a manual sharpening mode; and 
           [0017]      FIG. 12  is a fragmentary interior perspective view, portions removed, of the pencil sharpener of  FIG. 10  upon assembly and illustrated in an external power mode. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    With reference to the drawings wherein like numerals represent like parts throughout the Figures, a dual drive pencil sharpener is generally designated with the numeral  10 . The pencil sharpener  10  is configurable in a manual mode or an external power mode for sharpening a pencil and is further adapted to sharpen both a carpenter&#39;s pencil  12  and a Number 2 pencil. Alternatively, the pencil sharpener  10  may readily be adapted to sharpen various other types of pencils. 
         [0019]    The pencil sharpener  10  has a slightly tapered, quasi-cylindrical housing  20  principally defined by two cooperative housing shells  22  and  24 . The shells  22  and  24  interlock along a generally planar parting interface which further defines a central axis A ( FIG. 5 ). The shells are exteriorly traversed by a spaced series of wave-like ridged groups  21 ,  23  and  25 . Pencil shavings are initially retained within the housing  20 . Shell  24  has an axially slidable panel  26  to allow removal of retained pencil shavings. 
         [0020]    The pencil housing has a working input end  30  which includes a quasi-cross-shaped slot  32  adapted to either accept a carpenter&#39;s pencil  12  or a Number 2 pencil (not illustrated). Other slot configurations are possible. The opposing end  40  of the housing includes an opening  42  which provides access to a hexagonal socket  44 , the function of which is described below. 
         [0021]    Interiorly extending structures of the shells  22  and  24  cooperate to interiorly mount and form an enclosure  50  for a sharpener assembly  60 . Three interior axially spaced shelf bearings  52 ,  54 , and  56  project from the shells  22  and  24  and an axially spaced cam-like retention rim  58  radially projects integrally from the shells  22  and  24 . Bearings  52 ,  54  and  56  and rim  58  are formed in substantially identical arcuate sections and are generally symmetric about the central axis A which also functions as an operative rotational axis. The composite shelf bearings  52 ,  54  and  56  are substantially annular in shape. 
         [0022]    The sharpener assembly  60  includes a medial platform  62  which integrally connects with an upper mount frame  66 . A blade  68  is mounted to the frame  66  at an angle to the central axis A through the assembly to present a cutting edge to thereby produce a generally conically shaped point to a Number 2 pencil and/or a quasi-truncated conical shaped point to the carpenter&#39;s pencil. The medial platform  62  includes a circumferential annular recess  64  which is generally complementary with the medial shelf bearing  52  so that upon mating with the bearing, the medial platform  62  is freely rotatable around the bearing  52  within the housing  20  and about the central axis A. 
         [0023]    The upper portion of the frame  66  supports an upper annular platform  70  which also includes a recess  72  and mates in bearing relationship with an upper shelf  54  for rotational inter-engagement therewith. 
         [0024]    With reference to  FIG. 8 , the working end  30  has a generally disk-like panel  34  which includes the cross-shaped slot  32  and, at its edge, also includes a peripheral circumferential intermediate annular recess  38 . The recess  38  receives the shelf bearing  56 . The working end is supported at the top of the upper platform  70  and is generally independently rotatable therewith. 
         [0025]    With reference to  FIG. 8-12 , an elongated cage-like coupler  80  integrally extends below the medial platform  62  and is rotatably fixed with respect to the platform  62  and the frame  66 . The coupler  80  has a central axial cavity  81  and a pair of opposed axial slots  82  (only one slot illustrated). Angularly spaced, radially projecting, axial guides  83  extend from the coupler to stabilize the coupler movement. The lower underside of the coupler terminates in the hexagonal socket  44 . Other torque drive interfaces are also possible. 
         [0026]    A plug  84  includes a cross-bore  86  which receives a follower rod  88 . The diameter of rod  88  is commensurate with the width of the slots  82 , but is slightly smaller to allow sliding axial movement in the slots  82 . A coil spring  90  is disposed at the top of the plug  84 . The spring  90  and the plug  84  are disposed in the cavity  81 . Portions of the coupler body are removed in  FIGS. 11 and 12  for clarity. One end (upper) of the spring  90  engages the underside of the platform  62  to bias the plug  84  and follower rod  88  away from the platform (downwardly in  FIG. 11 ). 
         [0027]    The retention rim  58  includes a pair of cooperative ramps or cams  92  which lead to a detent  94  at diametrally opposed rim locations. The end portions of rod  88  rotatably follow the contours of the retention rim including the cams  92 . The detents  94  (only one illustrated) are dimensioned to rotatably capture the ends of the follower rod  88 . 
         [0028]    As best illustrated in  FIG. 11 , in a manual mode the opposed ends of the rod  88  are received in the opposed detents  94 . Because the rod rotatably engages the side walls of the coupler slots  82  under the bias of spring  90 , the sharpener assembly  60 , including the blade, is essentially rotatably fixed with respect to the housing  20 . An electric/battery powered drill preferably provides the driver power. 
         [0029]    With reference to  FIG. 12 , in the event that a torque drive in the form of a hexagonal driver is inserted into the socket  44  and rotatable with the socket, the plug  84  lifts against the bias of the spring  90  to displace the rod  88  from the detents  94 , and correspondingly the sharpener assembly  60  is now rotatable relative to the sharpener housing  20 . 
         [0030]    It will be appreciated that the sharpener  10  is operable in one of two drive modes. In a manual mode a pencil is inserted into the end  30  of the sharpener and the sharpener is manually rotated by rotating the housing  20  about the axis to sharpen the point while the pencil is held stationary. The rod  88  engages the detents under the bias of the spring  90 , and thus sharpener assembly  60  is rotatably fixed with the housing  20 , while the end  30  is stationary with the pencil. 
         [0031]    In an external drive mode, a driver is inserted into the socket  44  which is in the fixed rotational relationship with the sharpener/coupler. Upon rotation of the driver, the sharpener assembly  60  rotates within the housing  20 , and thus the pencil, which is firmly grasped, is sharpened under the drive of the external driver.