JP2008105293A - Electric pencil sharpener - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric pencil sharpener with an inexpensive configuration by lowering a high precision requirement of an excessive shaving inhibiting mechanism component. <P>SOLUTION: The electric pencil sharpener includes a cutter which has a helical cutting blade on a columnar surface and also, rotary shafts arranged on both ends, and bearing parts for retaining the rotary shafts on both ends. The electric pencil sharpener comprises a cutter bearing having a stepped part on the outer shape of at least one bearing part, a cutter holder having a pencil insertion hole and retaining the cutter bearing and a spring for urging the cutter bearing to the direction reverse to the pencil insertion hole, wherein the sharpener is configured so that the cutter bearing is pressed to the direction reverse to the urging direction of the spring with the tip of the shaved pencil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric pencil sharpener having a configuration in which when a pencil is shaved to a predetermined core thickness, the cutter is separated from the cutting surface of the pencil to automatically prevent excessive sharpening.

  FIG. 5 is a sectional view of a cutting mechanism portion of a conventional electric pencil sharpener. Reference numeral 12 denotes a cutter holder having a pencil insertion opening 13, and a cylindrical cutter 17 is pivotally supported by the cutter holder 12 by a cutter shaft 14 to cut the pencil inserted into the insertion hole 13.

  A mechanism for moving the cutter 17 away from the cutting surface B of the pencil and its operation will be described below. The pencil tip A to be sharpened advances in the right direction (rearward) in the figure, thereby sliding the tip contact plate 18 fitted in the guide groove 19 of the cutter holder 17 backward. The reaction lever 20, which is engaged at one end with the core tip contact plate 18 and is rotatable, rotates counterclockwise around the fulcrum 21 by this slide, and the rear end abuts against the other end of the reaction lever 20. The cutter shaft 14 is slid forward. When the cutter shaft 14 slides a required amount forward, the groove portion 22 formed at the front end portion of the cutter shaft 14 corresponds to the position of the bearing portion 15 that is smaller than the width of the groove portion 22.

Since the cutter holder 12 rotates around the pencil, a centrifugal force acts on the cutter 17 and the cutter shaft 14, and therefore the cutter shaft 14 moves outward by the depth of the groove 22. That is, the cutter shaft 14 moves in a direction away from the cutting surface B of the pencil by a certain angle with the rear end as a fulcrum, and the cutter 17 supported by the cutter shaft 14 is separated from the cutting surface B and stops cutting. (See Patent Document 1).
Japanese Patent Laid-Open No. 60-18395

  However, in the conventional configuration, each part has been required to have high accuracy in order to separate the cutter from the cutting surface when the pencil tip becomes a predetermined tip thickness. In particular, the dimension “a” of the connecting portion of the core contact plate 18 and the reaction lever of FIG. 5, the height “b” and the position “c” of the fulcrum 21, the position “d” of the cutter shaft groove, the bearing 15 The position e dimension and the shape of the cutter shaft tip f and the like required high precision. For example, if the accuracy of any of the parts is poor, the cutter will move away from the cutting surface before the pencil lead reaches a predetermined thickness, and the groove of the cutter shaft will remain after the lead has reached a predetermined thickness. If it is not located in the bearing part, the cutter will not move away from the cutting surface indefinitely, preventing over-cutting.

  Also, in the positional relationship between the outer diameter of the cutter and the tip contact plate, the cutter will not rotate smoothly if it comes into contact. If the gap is large, the tip of the pencil will enter the gap and the tip contact plate will slide. Disappear.

  As described above, since high precision is required for the dimensions of each part and the number of management items increases, there is a problem that the parts must inevitably be expensive.

In order to solve the above-described conventional problems, the pencil sharpener of the present invention includes a cutter having a spiral cutting blade on a cylindrical surface and having its own rotary shaft at both ends, and a bearing that holds the rotary shafts at both ends. A cutter bearing having a step and an outer shape of at least one bearing portion, a cutter holder having a pencil insertion hole and holding the cutter bearing, and the cutter bearing in a direction opposite to the pencil insertion direction. It comprises a spring for biasing, and has a configuration in which the tip of the pencil being cut contacts the cutter bearing.

  With the above configuration, the number of parts required to have high accuracy is reduced, and thus an inexpensive configuration is possible.

  As described above, according to the present invention, an inexpensive configuration can be achieved by reducing the high accuracy requirement of the over-cut prevention mechanism component.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an electric pencil sharpener according to Embodiment 1 of the present invention, FIG. 2 is a side view of the cutting mechanism, and FIGS. 3 and 4 are cross-sectional views thereof. In the figure, reference numeral 1 denotes a cutter having a spiral cutting blade on a cylindrical surface and a pinion 1a disposed at one end, the cutter shaft 2 is fixed to the cutter 1, and the cutter bearing 3 holds both ends of the cutter shaft 2 rotatably. It has a U groove. The cutter bearing 3 has a stepped portion 3a on one outer shape of two U grooves holding the cutter shaft. The cutter holder 4 has a U groove 4a and a pencil insertion hole 4b for holding the cutter bearing 3 in a slidable manner. Here, as shown in FIG. 3, the cutter clip 5 is attached to both U-grooves 4 a of the cutter holder 4 after the cutter 1 and the cutter bearing 3 are both fitted in the U-groove 4 a of the cutter holder. The spring 6 urges the cutter bearing 3 in the direction opposite to the direction in which the pencil 7 is inserted, and the internal gear 8 meshes with the pinion 1 a of the cutter 1.

  The operation of the electric pencil sharpener configured as described above will be described. At the same time as the pencil 7 is inserted into the pencil insertion hole 4b of the cutter holder 4, a start switch (not shown) is activated and a motor (not shown) rotates. The rotation is transmitted to the cutter holder 4 and, at the same time as the cutter holder 4 rotates, the pinion 1a of the cutter 1 meshes with the internal gear 8, so that the cutter 1 also rotates and the pencil cutting operation is started. The pencil 7 is cut by the cutter 1 and at the same time, the lead presses the lead contact part 3 b of the cutter bearing 3. As a result, the cutter bearing 3 is moved in the left direction in the figure against the urging force of the spring 6. Here, when the core of the pencil 7 has a predetermined thickness (FIG. 4), the step 3a of the cutter bearing 3 is positioned at the end of the U groove 4a of the cutter holder 4, and the cutter 1 is the cutting surface of the pencil. Get away from.

  Here, when considering the position where the cutter 1 is separated from the cutting surface of the pencil, only the dimension g of the stepped portion 3a to the core end abutting portion 3b of the cutter bearing 3 and the end surface position h dimension of the U groove of the cutter holder 4 are greatly affected. You can see that That is, as long as the dimensions g and h are managed with high accuracy, a stable core thickness can be obtained.

  Further, also in the positional relationship between the outer diameter of the cutter 1 and the tip contact portion 3b of the cutter bearing 3, both ends of the cutter shaft 2 are held by the cutter bearing 3, so that the tip contact plate 18 is provided as in the conventional example. Compared with the configuration provided in the cutter holder 12, the relative position can be easily increased in accuracy, and the tip contact portion abuts on the outer diameter of the cutter 1 to hinder the rotation of the cutter 1 or more than necessary. There is no gap and the tip of the pencil will not enter the gap.

  The configuration for preventing excessive shaving according to the present invention is useful as an electric pencil sharpener because an inexpensive configuration is possible by reducing the high precision requirement of the mechanical parts.

Cross-sectional view of the configuration of the electric pencil sharpener in Embodiment 1 of the present invention Side view of cutting mechanism part of electric pencil sharpener in embodiment 1 Sectional drawing of the cutting mechanism part of the electric pencil sharpener in Embodiment 1 Sectional drawing of the principal part of the cutting mechanism part of the electric pencil sharpener in Embodiment 1 Sectional view of the cutting mechanism of a conventional electric pencil sharpener

Explanation of symbols

1 Cutter 2 Cutter Shaft 3 Cutter Bearing 4 Cutter Holder 6 Spring

Claims (1)

A cutter having a spiral cutting blade on the surface of the cylinder and having its own rotating shaft at both ends,
A cutter bearing having a bearing portion for holding the rotating shafts at both ends, and having a stepped portion on the outer shape of at least one bearing portion;
A cutter holder having a pencil insertion hole and holding the cutter bearing;
A spring for urging the cutter bearing in a direction opposite to the pencil insertion direction;
An electric pencil sharpener having a configuration in which the cutter bearing is pressed in a direction opposite to a biasing direction of the spring with a core of a pencil being cut.