Patent Publication Number: US-9408454-B2

Title: Pencil

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of application Ser. No. 12/267,170 filed Nov. 7, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention concerns a pencil comprising a lead, a protective cap and a device for shaping the lead in the protective cap. 
     Pencils of the above-indicated kind are known, for example from DE 196 16 613 C1. In accordance therewith the lead is axially displaceable, more specifically by means of a spindle drive. When the protective cap is fitted the lead can be advanced until it reaches the shaping device. As it rotates about its axis in the further advance movement, it can be sharpened by further actuation of the spindle drive, by means of the shaping device. As sharpening is effected by actuation of the spindle drive the advance is fixedly predetermined in the sharpening operation. More specifically it corresponds to the pitch of the spindle used. 
     The object of the invention is to make the axial movement of the shaping device with respect to the lead individually selectable. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention the specified object is attained in that the shaping device is displaceable axially with respect to the lead when the protective cap is fitted. 
     It is therefore not the lead that is displaced within the pencil with respect to the shaping device, as is the case with the pencil disclosed in DE 196 16 613 C1, but rather conversely the shaping device is displaced with respect to the lead. That means that the axial displacement is no longer coupled to the spindle drive and can be individually selected. 
     In accordance with the invention the shaping operation can include a sharpening operation and/or a cutting operation. The corresponding tool therefore involves for example a sharpener. It is however also possible to use for example a blade which is pivotable and/or deformable against an elastic return force. Together with that blade it is possible to use a guide template. 
     So that the shaping device does not always bear against the lead in accordance with a particularly preferred embodiment of the invention there is provided an elastic return force which biases the shaping device into its rest position. The shaping device is therefore urged away from the lead in the non-actuated state. 
     In accordance with the invention preferably a particularly simple structure is afforded by an elastic device which is pressure-loaded to produce the return force. 
     In that respect it can involve for example a coil spring. 
     In accordance with a particularly preferred embodiment of the invention a handle for axial displacement of the shaping device with respect to the lead coincides with a handle for actuation of the shaping device. The shaping device is therefore simultaneously displaced axially in a direction towards the lead and actuated, by means of the handle, for example by rotation. That dual function of the handle simplifies the sharpening procedure. 
     Preferably in accordance with the invention there is provided a sleeve which receives an end portion of the protective cap and to which the shaping device is coupled for axial displacement and/or for actuation. That sleeve accordingly represents the above-mentioned handle. 
     Preferably in accordance with the invention the sleeve has a bottom portion for limiting the extent of the displacement of the shaping device with respect to the lead. That ensures, in the case of the sharpener as the shaping device, that excessive sharpening is avoided. 
     In accordance with a particularly preferred embodiment of the invention there is provided a device for limiting the extent of the displacement of the shaping device with respect to the lead. That limiting device can on the one hand obviate excessive sharpening. It can however also serve to limit excessive displacement of a blade used for shaping the lead. 
     Preferably in accordance with the invention the shaping device is visible from the outside at least in its working position. That provides that the extent of sharpening is visible during the sharpening operation. The sharpening operation can be concluded when the lead is sufficiently sharp for the respective individual requirements. 
     In particular to make the shaping device visible from the outside in its working position, a preferred feature of the invention provides that the protective cap is at least portion-wise transparent. That means that the shaping device arranged within the protective cap is visible from the outside. 
     The pencil can have a cartridge, within which the lead is axially displaceably held. In that way it is possible for example to adjust a protruding length of the pencil out of the cartridge prior to and/or after the sharpening operation. 
     In that respect in a further preferred feature according to the invention there is provided a rotary drive for displacement of the lead with respect to the cartridge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in greater detail hereinafter by means of a preferred embodiment with reference to the accompanying drawings in which: 
         FIGS. 1( a ) through ( e )  diagrammatically show an embodiment of a pencil according to the invention in various operating conditions, 
         FIGS. 2( a ) and ( b )  show sectional views on an enlarged scale of  FIGS. 1( c ) and ( d ) , and 
         FIGS. 3 and 4  show similar views to  FIGS. 1 and 2  but of another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The stick or pencil shown in  FIGS. 1 and 2  includes a cartridge  10 , a shank  12 , a lead  14  and a protective cap  16 . A sharpener  18  is held in the protective cap  16 . The sharpener  18  is displaceable in the axial direction with respect to the lead  14  by means of a sleeve  20  with a bottom portion  22  against the elastic return force of a coil spring  24 . 
     A rotary drive serves for axial displacement of the lead  14  with respect to the cartridge  10 , the rotary drive not being shown in the drawing as it is usual in pencil technology. The rotary drive is actuated by rotation of the shank  12  with respect to the cartridge  10 . 
     The protective cap  16  is made of a transparent material, for example transparent plastic material. 
       FIG. 1( a )  shows the pencil with a blunt lead. By actuation of the rotary drive, that is to say by rotation of the shank  12  with respect to the cartridge  10 , the lead  14  can be pushed out of the cartridge  10  to the desired projecting length, as shown in  FIG. 1( b ) . In that respect the projecting length can be freely selected and can be adjusted by suitable actuation of the rotary drive. 
     For sharpening the lead  14 , the protective cap  16  is fitted on to the cartridge  10  as shown in  FIG. 1( c )  and  FIG. 2( a ) . It is supported on the shank  12 . In that condition the coil spring  24  is relieved of load to a rest position. 
     Actual sharpening of the lead  14  is effected by the sleeve  20  being displaced towards the right in the Figures with respect to the protective cap  16  and thus also with respect to the lead  14 , and being rotated at latest when the sharpener  18  makes contact with the lead  14 .  FIG. 1( d )  and  FIG. 2( b )  show the pencil in an operating condition in which the sleeve  20  and thus the sharpener  18  are displaced towards the right to the maximum with respect to the protective cap  16  and the lead  14  because the bottom portion  22  bears against the protective cap  16 . If the sharpener  18  were still further displaceable, the cartridge  10  would be sharpened. The coil spring  24  is stressed to the maximum in that operating condition. It therefore biases the sharpener  18  into its rest position as shown in  FIG. 1( c )  and  FIG. 2( a ) . 
     The sharpener  18  and the lead  14  are visible throughout because of the transparency of the protective cap  16 , that is to say during the actual sharpening operation. 
     The embodiment of  FIGS. 3 and 4  functions as follows: 
       FIG. 3( a )  shows the pencil with a blunt lead  14 . Firstly the lead is advanced by means of a rotary mechanism (not shown) so that the length by which the lead  14  protrudes from the cartridge  10  is increased. The protective cap  16  is then fitted. That rest condition is shown in  FIG. 3( b )  and  FIG. 4( b ) . 
     When a knob  23  is depressed in that operating position a blade  25  slides along a guide template  26  and cuts off the lead  14 . The knob  23  is displaceable axially against the elastic return force of a coil spring  28  to cut off the lead  14 , until it encounters an abutment  30  on the protective cap  16  to limit the extent of the displacement. That condition is shown in  FIG. 3( c )  and  FIG. 4( a ) . 
     After that the protective cap  16  is removed again. The pencil is now in the operating condition shown in  FIG. 3( d )  which differs from that shown in  FIG. 3( a )  only in that the lead  14  is sharpened by being cut off. 
     Once again therefore it is to be noted that in the second embodiment also the blade  25  serving as the shaping device is axially displaceable independently of the lead  14 . 
     Flexing of the blade  25  as shown in  FIG. 3( c )  and  FIG. 4( a )  takes place against an elastic return force so that, after release of the knob  23  and the return movement thereof by the spring  28 , the blade  25  again assumes the rest position or shape shown in  FIG. 3( b )  and  FIG. 4( b )  respectively. 
     The features of the invention disclosed in the foregoing description, the claims and the drawing can be essential both individually and also in any combinations for implementing the invention in its various embodiments. 
     Points of explanation relating to  FIG. 1 :
     (a) blunt lead   (b) pre-rotating the lead to the sharpening length   (c) fitting the protective cap   (d) rotating the sharpener and in so doing pressing it lightly against the tip   (e) pointed lead ready for makeup