Patent Publication Number: US-6334256-B1

Title: Sharpener unit

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a so-called container sharpener having a pencil or core sharpener and a cover housing that surrounds the sharpener and catches shavings, the housing including a floor part and a closing hood that can be detachably secured thereto. 
     In container sharpeners of this type, the detachable hood serves to catch shavings. It prevents undesired accumulation in the surrounding area during sharpening. 
     To promote efficient production, it is known to manufacture the cover housing, which comprises a floor piece and a detachably-secured hood, as a separate component and to secure a separately-manufactured sharpener to the floor of the cover housing as a conventional, inexpensive practice in mass production. This sharpener typically includes only a sharpener housing, which comprises plastic or metal, e.g., aluminum, and surrounds a guide channel having a conical tip end, as well as a cutting blade that is screwed to the sharpener housing, or extrusion-coated in one piece with the housing with the use of the sharpener-housing material. The sharpener is a commonplace, mass-produced item. Container sharpeners having a separate cover housing comprising a floor part and hood and a pencil or core sharpener secured therein are known from DE 27 45 600 A1, in which case the sharpener is secured to the floor part of the cover housing through a clamp connection. 
     Primarily for reasons of aesthetics, cover housings for such sharpener units have a complicated design. They are often augmented with additional functional components whose technical or design-related construction is tailored to specific customer preferences, and increases the costs of producing the cover-housing parts, particularly the hood. Because customer preferences in terms of the technical and design-related construction of the sharpener can vary greatly, the piece numbers demanded by the market are too small to justify a high production outlay for the cover housing and its technical and design-related construction. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to solve this problem using technical means that lay the foundation for efficient mass production of the cover housing. This object is accomplished by at least one of the parts of the cover housing being provided with notched projections, which project into the housing, for securing the sharpener through clamping or snapping, wherein the notched projections are positioned and configured so that both a small-format sharpener due to pressure on the outside walls of its housing from the outside inward, and a large-format sharpener due to expansion pressure on the wall regions of its housing from the inside outward can be secured between the notched projections. With this solution, the notched projections can selectively be pressed inward from the outside due to pressure on the outside walls for the clamping or snap connection of a small-format sharpener, or they can be expanded outward due to expansion pressure against wall regions of the housing, to accommodate a large-format sharpener. Of course, the exertion of the expansion force stipulates that the affected wall regions be externally accessible to the notched projections. 
     With the invention, it is no longer necessary to produce a separate cover housing for sharpeners of different formats. If the connection of the sharpener to the cover housing is effected by clamps or snaps, it is a type of connection described in detail in Carl-Otto Bauer&#39;s “Handbuch der Verbindungstechnik [Handbook on Connection Techniques,” Carl Hanser Verlag [publisher], Munich, Vienna, 1991, pp. 269 et seq. and 295 et seq. The ability of the cover housing to secure sharpeners of different formats in clamp or snap connections, and position their guide channel for the pencil or core end precisely opposite the throughgoing opening of the cover housing, forms the basis for a viable piece-number production of cover housings or their components. 
     Another object of the invention capitalizes on the fact that the sharpener housings of large-format sharpeners, which are usually made from injected plastic, have thin walls. According to the invention, this injection-molding technology prevents sink marks and also saves material. As a result, the outside of the housing floor of large-format sharpeners in particular is cleaved, with the side walls of the sharpener housing freely projecting downward from the floor. This gives the sharpener, which is positioned on a base, a compact design, and by nature offers the option of accessing the downward-projecting side walls of the sharpener housing through the notched projections. In this instance, the invention employs conditions in large-format, mass-produced sharpeners that therefore need not be individually adapted for their intended use inside a cover housing in accordance with the invention. 
     Another embodiment of the invention has notched projections forming a U-shaped clamping rib. This embodiment allows a simple, yet especially effective method of attaining a precise positioning of the respective sharpener inside the cover housing using a clamping technique. 
     Another embodiment of the invention relates to a particulary effective embodiment of the clamp or snap connection in the clamping of a large-format sharpener. The peripheral wall intended for securing the closing hood of the cover housing, or parts of such a peripheral wall of the floor part, together with the notched projections projecting upward from the floor part, form a clamping groove. The side walls projecting downward beyond the housing floor of a large-format sharpener can be clamped particularly effectively between the side walls of this groove. This improves the reliable positioning of the position-fixed, large-format sharpener on the bottom part of the cover housing. Consequently, during sharpening, the sharpening forces acting on the sharpener or the sharpener housing are absorbed especially well. The sharpener will not loosen inside the cover housing, even with the occurrence of heavy vibrations. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     The subject of the invention is explained in detail below by way of embodiments illustrated in the figures in which: 
     FIG. 1 is a view in perspective of an entire sharpener unit according to the invention, in the final state of assembly; 
     FIG. 2 shows the parts of the sharpener unit according to FIG. 1, with a small-format sharpener, in an exploded view; 
     FIG. 3 shows the parts of a sharpener unit that are similar to FIG. 2, with a large-format sharpener, in an exploded view; 
     FIG. 4 shows an enlarged view in perspective of the floor part of the cover housing; 
     FIG. 5 is a side view of the floor part in the viewing direction of the arrow IV in FIG.  3 ;and 
     FIG. 6 is a plan view of the top side of the floor part, which faces the sharpener. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The sharpener unit selectively includes a large-format pencil or core sharpener  1  or a small-format sharpener  2  and a cover housing  3 , which surrounds and secures the respective sharpener  1  or  2 . This cover housing  3  comprises a floor part  4  and a hood  5 . 
     The lower edge region  6  of the hood  5  can be clamped to the floor part  4 . For this purpose, the lower edge region  6  of the hood  5  is slid over the peripheral wall  8 , which projects upward out of the base  7  of the floor part  4  and, in the illustrated embodiment, is closed all the way around. With respect to the peripheral wall  8 , the edge region  6  of the hood  5  is dimensioned such that the hood  5  is clamped by the edge region onto the outside surface of the peripheral wall  8  in a press fit. The hood  5  is advantageously positioned precisely with its lower edge  9  on the outside surface or outside cover surface  10  of the base  7 . 
     A U-shaped clamping rib  11  projects upward from the base  7  of the floor part  4 . The U-shaped clamping rib  11  is disposed in the space that is limited by the peripheral wall  8 . The free ends of the two parallel U legs  12 ,  13  of the clamping rib  11  project into the center of the base  7 . The crosshead  14  of the U shape of the clamping rib  11  extends parallel to the adjacent part of the peripheral wall  8 , thereby forming a spacing gap  15 . A matching spacing gap  15  is cut out between the parallel legs  12 ,  13  of the U shape of the clamping rib  11  and the inside surfaces of the peripheral wall  8  or the one part of the polygonal base section  16  forming a part of the peripheral wall  8 . This spacing gap  15  serves to receive the lower ends  17  of the side walls  18 ,  19  and the rear wall  20  of the housing of the larger sharpener  1  in a press fit. To increase the lateral elastic bending capability of the outside parallel leg  13  and the crosshead  14  of the clamping rib  11 , the recesses  21 ,  22  are provided there. This bending can take place at a right angle to the two flanks of the crosshead  14  and the parallel legs  12 ,  13 . In this regard, the lateral rebounding capability of the parallel legs  12 ,  13  and the crosshead  14  also serves to secure the smaller sharpener  2  to be in contact with the inside walls of the parallel legs  12 ,  13  and the crosshead  14 . This is also a clamping connection. 
     The throughgoing opening  24  passes through the front side  23  of the hood  5 . This throughgoing opening  24  is open at the height of the positioning edge  9  of the hood  5 . It can be closed by a shutter  25 . The shutter  25  is guided longitudinally in longitudinal guides  28  on the inside of the hood  5 . At the outer end of the shutter  25 , an integral, outward-projecting gripping projection  29  serves in the manual opening and closing process, and as a cover-housing stop in the open and closed positions. 
     Moreover, the floor part  4  is provided with receiving slots  30 ,  31  for a cleaning implement  32 . The receiving slots  30 ,  31  act as clamping slots. In the fixed position, the cleaning implement  32  is also held under the hood  5  so as to be shielded from the surroundings. In the fixed end position inside a shielded opening  34 , the gripping end  33  of the implement rests against the floor part  4 . 
     FIG. 3 clearly depicts the large-format sharpener  1  from its underside. This view illustrates the cleaved structure of the floor of the sharpener housing  35  of the large-format sharpener  1 . It is a plastic injected part having thin-walled side walls  18 ,  19 , which appear compact on the outside, and a thin-walled rear wall  20  and front wall  37 , into which the opening  36  of the sharpener channel is cut. The peripheral edges  38  and these side walls form a base surface for the sharpener housing  35  on the surface  39  of the floor part  4 . In the clamped or joined position, the side walls  18 ,  19  and the rear wall  20  of the large-format sharpener housing  1  are clamped in the spacing gap  15 , which is limited between the clamping rib  11  and its parallel legs  12 ,  13 , on the one hand, and the peripheral wall  8  and the polygonal base section  16 , on the other hand. This clamping also assures reliable positioning on the floor part  4 , even with the occurrence of vibrations.