Cutlery – Static pencil sharpener – With debris receiver
Reexamination Certificate
1999-09-10
2001-08-28
Rachuba, M. (Department: 3724)
Cutlery
Static pencil sharpener
With debris receiver
C030S457000
Reexamination Certificate
active
06279237
ABSTRACT:
The invention relates to a sharpener having a housing and, in the latter, a guide channel into which an introduction opening for a pencil opens out, and having a blade which is fixed in the region of a housing abutment surface.
Such a sharpener is used, in particular, as a cosmetics sharpener for regenerating and shaping as desired the tip of a cosmetics pencil or core. Such cosmetics sharpeners are usually designed as so-called container-type sharpeners. For this purpose, a shaving-collecting cap, which serves for receiving the sharpening waste, is pushed or clipped onto that end of the housing which is located opposite the opening-mouth base or introduction opening for introducing the pencil. In the rest state, such cosmetics sharpeners are usually fixed, in the manner of a protective cap, on the use end of a cosmetics pencil or core in order also to protect the use end of the pencil, in particular its core, in relation to the surroundings when it is not in use. In the ideal case, the assembly comprising housing and possibly shaving-collecting cap fitted onto the housing thus has the outline of a protective cap, as is also used, for example with pencils for writing purposes, for covering the core tip when the pencil is not in use.
In the case of pencils for writing purposes, this protective cap is often also provided with a clip for attaching it inside a pocket, e.g. in the inside pocket of an item of clothing. Such attachment clips can also be used for cosmetics sharpeners which, when the pencil is not in use, assume the function of a protective cap for the core end. When not in use, cosmetics pencils are usually stored by the user in pockets, bags, cases or the like. It is particularly important in this case to protect the surroundings with respect to the use end or the core.
In this not-in-use state, however, it is desired for the sharpener to project as little as possible beyond the pencil or core in the radial direction in relation to the pencil or core axis. It is precisely in this direction that it is to be configured in as space-saving a manner as possible in order to be able to fulfill its function as a pencil cap, in the stored state, in an ideal, space-saving manner. This is problematic, however, in particular in terms of the design and fixing of the blade.
The blade required for such a sharpener usually consists of a metallic material, e.g. of a heat-treatment steel. The blade, which is normally in the form of an elongate shallow cuboid, is ground on one longitudinal flank for the purpose of forming a blade cutting edge. In a conventional and tried-and-tested manner, this blade is fixed centrally on the housing by means of a single screw. The screw passes through the blade in the region of a through-passage hole. The basic construction of such a sharpener with screwed-on blade is known from EP 0 078 512 A1.
However, a minimum screw diameter, which is necessary for strength reasons, requires a certain minimum width of the essentially shallow-cuboidal blade. Otherwise, the through-passage hole would result in the inherent strength of the blade being weakened to a considerable extent. It is precisely in the central region, i.e. in the through-passage region of the fixing screw, that the blade is subject to the highest stressing during the sharpening operation, since the highest cutting forces occur there. In the case of the usually wood-encased cosmetics pencils, this part of the blade is responsible for shaving away the wooden casing, which requires considerably higher cutting forces than the shaping of the core, which in the case of cosmetics pencils is usually of soft consistency.
On account of the blade which is used having a minimum width which is necessary for the central screwed fixing, a sharpener housing having a hollow-conical guide channel in the inner region has a space-related problem in the circumferential region of the cone foot if it is desired for the sharpener to be of a space-saving construction. This is because, in this region, the design means that the blade is of the same width as the central region provided with the screw-hole. For strength reasons, this is also desirable or necessary because the casing, of the usually wood-encased pencil, which is to be shaved in this central region produces the highest cutting pressure. Accordingly, the blade has to absorb the highest reaction pressure at this location. It would thus be helpful for the blade to be fixed as close to this location as possible, which, on account of the problems with space, is very difficult to achieve with the usually centrally arranged fastening screw if the abovementioned space-saving construction is desired.
If it is desired to minimize this space problem in the circumferential region of the sharpener by designing the blade at this location with flanks which converge at an acute angle, then this would mean, in turn, a weakening in the inherent strength of the blade and would not provide any fixing on the housing.
In the case of a design previously known from DE 38 12 252 C1 or DE 39 32 586 C2, screwless fixing of the blade on the housing takes place by the blade being at least partially integrally encapsulated by injection molding. A similar screwless design is known from DE 30 41 313 C2, in which the blade is clamped by the subsequent welding of a cover plate to the sharpener housing. However, these solutions for fixing the blade involve very high outlay in terms of production, in particular in terms of injection molding, and save only a small amount of space, if any at all.
The object of the invention is thus, with a simultaneously space-saving construction of the sharpener, to achieve an advantageous and secure method of fixing the blade on the housing.
This object is achieved according to the invention by the features of claim
1
. For this purpose, there is two-point fixing of the blade at its two ends, i.e. two-ended blade fixing, and it is only in the region of the radially inner end of the blade, which is thus less problematic in terms of the space-related problem, that a separate fixing means, in particular a screw, is used as a fixing location. On account of the positioning, e.g. of a screwed connection, very close to the axis, there are no problems associated with accommodating the screw head within the casing region of the sharpener housing.
In contrast, in the region of the outer end of the blade, said end being in the vicinity of the introduction opening for introducing the pencil, the blade is clamped on the housing itself without a separate, additional fixing means, such as a screw, which would have its head projecting in a disruptive manner beyond the circumference of the sharpener housing. In this location, the blade has its outer end clamped behind a housing-side protrusion. This takes place by bending stressing being produced when the inner end of the blade is fixed, in that, in the region of the outer end, said blade is guided about a bending edge at the transition between a hollow-cylindrical region and a hollow-conical region of the guide channel.
EP 0 078 512 A1, which was mentioned in the introduction, does indeed describe a design of a sharpener in which the blade is secured at both ends, one blade end being inserted into a housing groove and the opposite blade end being secured on the housing by means of a screw. However, in the case of this known design, the blade is curved in a concave manner in the longitudinal direction, in relation to the sharpener housing, with the purpose of narrowing the guide channel, in that the cone angle, in relation to the center axis of a pencil which is to be sharpened, is smaller on the channel side which is directed towards the curved central region of the blade than the cone angle on the opposite channel side. Since the blade is thus subjected to negative prestressing, additional means are necessary for fixing the blade such that it is secured against displacement. In the case of the known sharpener, this is achieved by means of an adjustment screw of which the screw end is guided against the bearing side or abut
Greenberg Laurence A.
KUM Limited
Lerner Herbert L.
Rachuba M.
Stemer Werner H.
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