JPH0222099A - Pencil sharpener - Google Patents

Abstract

PURPOSE:To press a pencil to a cutter by proper force by providing the blade tip contact part, which strikes on the leading end part of the surface striking on the pencil of a cutter blade, to the region on the side opposite to the contact region of the cutter blade with the pencil with respect to the center of rotation of a cutter. CONSTITUTION:The blade tip contact stand 18 striking on the leading end part of the surface on the side striking on a pencil 8 of a cutter 5 is provided to the region on the side opposite to the contact region of the blade 5a of the cutter 5 with the pencil 8 with respect to the center of rotation of the cutter 5. When the cutter 5 is pushed by the pencil 8 to be ready to incline, said stand 18 supports the leading end of the cutter 5 and becomes the fulcrum Q at the time when the outer end part of the cutter 5 is inclined. Since this fulcrum Q becomes remote from a point J where the elastic pressure of a spring acts, the force pressing the blade 5a of the cutter 5 to the pencil 8 can be sufficiently increased and even the hard pencil 8 can be sharpened by sufficient force without bringing about the escape of the cutter 5.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a pencil sharpener.

BACKGROUND OF THE INVENTION First, an example of a conventional pinwheel-shaped pencil sharpener will be explained based on the drawings. In FIG. 3, 1 is a motor, 2 is a gear box equipped with a reduction gear, 3 is a rotating shaft for rotating the cutter, 4 is fixed to the rear end of the rotating shaft 3,
This is a gear that meshes with the reduction gear in the gear box 2.

5 is a cutter having a pinwheel shape as shown in FIG. 4, and the cutter 5 has a plurality of blades 5a formed radially. 6 is a pencil holder that becomes narrower toward the tip. As shown in FIGS. 4 and 5, an open lower portion is formed in the portion of the pencil holding portion 6 facing the cutter 5, and a portion of the pencil inserted into the pencil holding portion 6 is inserted into the open lower portion. It is starting to protrude from the inside. Also cutter 5
The blade 58 rotates in a position very close to the opening lower part, and is configured to strike a pencil protruding from the opening lower part and sharpen the pencil. A pencil feeding device 9 is rotatably held on the upper part of the pencil holding section 6, and feeds the pencil 8 inserted into the pencil holding section 6 while rotating.

Figure 6 shows the cutter 5 and its surroundings along the line A-A in Figure 4.
FIG. In Figure 6, 10
is a spring for pressing the cutter 5 downward in the drawing. A groove 3a is formed in the rotary shaft 3 in the vertical direction, and a protrusion (not shown) protruding from the inner periphery of the through hole of the cutter 5 fits into the groove 3a. Therefore, when the shaft 3 rotates, the cutter 5 also rotates. Also, the cutter 5 is somewhat slidable along the shaft 3. 11
is the wall plate on the back side of the cutter rotating section.

A cutter support portion 12 is formed around the shaft 3 and supports the center portion of the cutter 5. Cutter support part 1
The upper surface of 2, that is, the cutter contact surface is higher than the upper surface of wall plate 11. Wall plate 11, cutter support portion 12, and pencil holder 6 are integrally formed of hard synthetic resin.

The cutter 5 is pressed against the cutter support 12 by the spring 10.

As described above, the conventional pencil sharpener with a windmill-shaped cutter has a structure in which the cutter 5 is pressed against the cutter support part 12 that is formed integrally with the pencil holding part 6 that holds the pencil, and the pencil and the blade are separated. The relative distance between the two is determined by the configuration of the pencil holder 6 and the ivy support 12. That is, if the dimensional relationship between the pencil holder 6 and the cutter support 12 is uniform, the relative distance between the pencil and the blade will also be uniform. If the cutter support part 12 is higher, the cutter 5 will be farther away from the pencil, and if it is lower, the cutter 5 will be closer to the pencil.

Problem to be Solved by the Invention In the above example, the cutter 5 is attached to the cutter support part 1.
As shown in FIG. 7, the blade 5a is pressed by the pencil 8.
When the cutter 5 is pushed up in the direction of the arrow G, the cutter 5 tilts with the point P hitting the edge of the cutter support 12 acting as a fulcrum (S is the tilt angle). In this case, the distance between the point H on the cutter 5 where the elastic force F of the spring 10 acts and the fulcrum P is too short compared to the distance between the point I pushed up by the pencil 8 and the fulcrum P, and the spring 10 is at the tip of the cutter 5. There was a problem in that the force F' applied to the pencil 8 was small. If the force F was small and the pencil was hard, the cutter would easily escape, resulting in a small amount of cutting.

However, if the upper surface of the cutter support portion 12 is made wider, the distance between the point A and the fulcrum P becomes larger, and F' becomes larger, but there is a limit to the width due to the configuration of the cutter 5.

In addition, the spring 10 is changed to one with a high spring constant,
It is possible to strengthen the elastic force applied to the cutter 5, but if this is done, the cutter 5 and the cutter support 12
The frictional force between the two will become stronger and the rotational load will increase.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pencil sharpener that can press a cutter against a pencil with an appropriate force.

Means for Solving the Problems In order to solve the above problems, the present invention provides a surface of the blade that contacts the pencil in an area opposite to the area where the cutter blade contacts the pencil with respect to the center of rotation of the cutter. A cutting edge abutment part is provided that corresponds to the tip of the blade.

Effect With the above structure, when the cutter is pushed by the pencil and tries to tilt, the base supports the tip of the cutter, the outer edge of the cutter becomes a fulcrum when the cutter tilts, and the force of the spring acts. The point is further away from the fulcrum, and the force with which the blade presses down on the pencil is greater than with conventional ones.

EXAMPLE Hereinafter, an example of a pencil sharpener according to the present invention will be described. It should be noted that parts in this embodiment that are similar to the configuration of the conventional example shown in FIGS. 3 to 5 are given the same numbers as in the conventional example, and explanations thereof will be omitted.

In FIGS. 1 and 2, 15 is a wall plate of the cutter rotation part, 16 is a cutter support part, and 17 is a pencil holder that gradually becomes thinner toward the tip.

Reference numeral 18 denotes a blade edge contact portion formed around the wall plate 15 in a region opposite to the region where the blade 5a of the cutter 5 and the pencil 8 contact with respect to the center of rotation of the cutter 5. Wall board 1
5. The cutter support portion 16, pencil holding portion 17, and blade abutting portion 18 are integrally formed of hard synthetic resin.

The upper surface of the cutter support section 16 and the upper surface of the blade edge contact section 18 are higher than the upper surface of the wall plate 16.

It should be noted that the tip of the cutter 5 is not useful for sharpening pencils, and there is no problem even if it wears out somewhat due to rubbing against the upper surface of the cutting edge contact portion 18.

The operation will be explained below. When the blade 5a is pushed upward by the pencil 8, the cutter 5 tends to tilt with the point Q hitting the blade edge abutting portion 18 acting as a fulcrum. In this case, if the point on the cutter 5 where the elastic force F of 1° of the spring acts is Jl, and the point where the pencil 8 pushes up is K, then the ratio of the distance between the point J and the fulcrum Q to the distance between the pencil point and the fulcrum Q is is larger than that of the conventional one, and the force F' that the blade 5a gives to the pencil 8 is
It's also big. If the force F' is large, the blade 5a will not easily escape even when a hard pencil is inserted, and the pencil can be sharpened with sufficient force.

Effects of the Invention As described above, the present invention provides an area on the opposite side of the area where the cutter blade and the pencil touch with respect to the center of rotation of the cutter.
By providing the blade edge abutting portion at the tip of the side of the blade that comes into contact with the pencil, even if the cutter is pushed by the pencil and tries to tilt, its fulcrum will be located at the tip of the cutter. Therefore, the force with which the cutter blade presses down on the pencil can be made sufficiently large, so that even if a hard pencil is inserted, the cutter will not easily escape (it will sharpen very well). In addition, even if the elastic force of the spring that presses down on the cutter is relatively small, the force that the blade presses on the pencil can be maintained sufficiently large, so the elastic force of the spring can be reduced and the cutter and cutter can be It also has the effect of reducing the frictional force between it and the support part.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of a pencil sharpener according to an embodiment of the present invention, Fig. 2 is a front view of the same pencil feeding device, Fig. 3 is a central longitudinal sectional view of a conventional pencil sharpener, and Fig. 4 is the same. A front view of the pencil sharpener, Fig. 5 is a vertical sectional view taken along the pencil insertion hole of the pencil sharpener, Fig. 6 is a sectional view of the main part of the pencil feeding device, and Fig. 7 is the pencil feeding device. FIG. 2 is a cross-sectional view of the main part of the pencil inserted state. 3...Rotating shaft 10...Spring 15...Wall plate 17...Pencil holding part 5...Cutter 16...Cutter support part 18...Blade tip contact Department

Claims (1)

[Claims] a cutter having blades formed in a radial pattern; a rotation shaft for rotating the cutter; a cutter support formed around the rotation shaft; a spring that presses a center portion of the cutter against the cutter support; a pencil holding member for holding a pencil at a position where the cutter blade contacts the pencil; A pencil sharpener characterized by being equipped with a blade edge abutting part that corresponds to the tip of the side surface.