JP2554726Y2 - Pen for automatic drafting machine - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a pen for an automatic drafting machine in which a tip protruding a pen tip is fitted and fixed to a tip of a shaft.

(Prior Art) Not only a pen for an automatic drafting machine, but also in a writing instrument in general, it is common to fit and fix a tip projecting a pen tip to a tip of a shaft.

(Problem to be Solved by the Invention) A pen for an automatic drafting machine is used by being attached to an apparatus main body so as to fix a shaft. Therefore, the pen point is fixed via the shaft and the tip. At this time, if the pen tip is not concentric with the axis, the position of the pen tip with respect to the apparatus main body changes every time the pen is replaced, resulting in disturbed handwriting. Therefore, the shaft and the chip are required to be manufactured with as high accuracy as possible. Also, manufacturing costs must be considered.

In addition, there are shafts, tips, and therefore considerations that need to be made. For example, it is desired to select a material for the shaft that minimizes the amount of transmission loss of the ink contained therein. As a material of the tip fitted and fixed to the shaft, it is a priority selection condition to secure the fixing of the pen tip, rather than to reduce the amount of permeation of the ink.

As a result, it is considered that the shaft is preferably made of polyethylene, polypropylene, or the like, and the tip is made of polyacetal, ABS, AS, or the like.

However, even if these are combined, satisfactory fitting and fixing between the pen tip and the shaft cannot always be satisfied. The relative softness of the material of the shaft and the tip has an effect, but the force of the fitting fixation unnecessarily deforms the shaft, and it is not possible to effectively exert the bending precision, and the pen tip and the shaft The concentricity is insufficient, or the force of fitting and fixing is insufficient, so that the fixing cannot be performed reliably.

(Means for Solving the Problems) The present invention is a pen for an automatic drafting machine in which a tip protruding a pen tip is fitted and fixed to the tip of a shaft, and the shaft is softer than a chip. In addition, the shaft and the tip are fitted with a front fitting portion having a relatively large fitting force and a rear fitting portion having a relatively small fitting force. Further, the front fitting portion is formed on the inner wall of the shaft. The present invention provides a pen for an automatic drafting machine, which is formed by press-fitting in which an inwardly protruding portion formed on the tip comes into contact with a flat surface of a chip.

(Example) FIG. 1 shows an example of a small tube type writing instrument. The small tube nib 1 slidably inserts a fine rod 2 exhibiting self-elasticity, and a tip 3 for projecting and fixing the small tube nib 1.
Can be prepared as an integral assembly together with the temporary ink reservoir member 4 and the ink guide member 5 inserted into the bore of the temporary ink reservoir member 4, and is inserted and fixed to the shaft 6. That is, this example is also an example of a raw ink type writing instrument. Although not shown in the drawings, the shaft 6 may be integrally provided with a mounting portion to the apparatus main body as a flange portion, and the rear inner hole may be used as an ink tank as it is.

The tip 3 and the shaft 6 are made of the above-mentioned material. Here, the tip 3 is made up of a first rib 7, a second rib 8, a third rib 9, and a fourth rib 10. It has four annular ribs, and the first rib 7 is wider. Further, the outer diameters of the respective ribs are designed to be equal. Therefore, it can be said that a plurality of annular concave portions are formed. On the other hand, the shaft 6 has a first inward protrusion 11, a second inward protrusion 12, a third inward protrusion 13, and three annular inward protrusions on the inner wall. , The first inwardly protruding portion 11 is the first rib 7
, The width of which is smaller than that of the first rib 7 and the inner diameter thereof is designed to be smaller than the outer diameter of the first rib 7. That is, for the first inwardly protruding portion 11, the first rib 7
Is a flat surface. The second inwardly projecting portion is smaller than the inner diameter of the projecting base portion 14 of the first inwardly projecting portion 11.
The inner diameters of the 12 protruding bases 15 and the protruding base 16 of the third inward protruding portion 13 are designed to be larger than the diameters of the second rib 8, the third rib 9, and the fourth rib 10, and The second inwardly protruding portion 12 is formed by the second rib 8 and the third rib 9, and the third inwardly protruding portion 13 is formed by the third rib 9 and the fourth rib 10 with a small contact area. It is to be clamped by.

That is, the first ribs 7 are formed so that the edges as ribs do not come into contact with the first inward projecting portions 11.
And a large area, and the tip 3
Is a state in which the abutment force per unit area with respect to the shaft 6 is prevented from being partially increased, and the force as a sum total thereof, that is, the fitting force is relatively large so as to be relatively large. It is in. Although the second rib 8, the third rib 9, and the fourth rib 10 locally deform the shaft 6,
The fitting force as the total force for deforming the shaft 6 outward is relatively small. In this portion, the chip 3 is in a state of being fitted into the shaft 6 with concave and convex portions.

Next, another example is shown in FIG. Note that the same reference numerals are used for the basically same parts as those in the previous example.

In this example, the chip 3 is not provided with a rib. The chip 3 has only a flat surface as a side wall. On the other hand, on the inner wall of the shaft 6, an inwardly projecting portion 17 and an engagement step portion 18 are formed. Engagement step 18 from inward projection 17
Up to this point, a tapered inner hole 19 is formed, but either the inner diameter of the inwardly protruding portion 17 or the inner diameter of the engagement step portion 18 may be smaller.

The relationship of the inward projection 17 to the chip 3 is equal to the relationship of the first inward projection 11 to the chip 3 in the previous example. The engaging step 18 is smaller than the outer diameter of the rear end of the chip 3 and serves as a press-fitting portion. However, the engaging step 18 has a narrow contact area and deforms the shaft 6 outward. The fitting force as the total force is also relatively small as in the previous example.

As described above, in each of the two examples, the ribs and the inwardly protruding portions are all annular, but may be non-annular because a slit or the like serving as an air hole is formed. In addition, a writing instrument using an ink occluding body can be used. Furthermore, a ballpoint pen or the like is also appropriate.

(Effect of the invention) The shaft is made of a synthetic resin that is softer than the chip.
The shaft and the chip are fitted with a front fitting portion having a relatively large fitting force and a rear fitting portion having a relatively small fitting force, and the front fitting portion is formed on an inner wall formed on an inner wall of the shaft. Since the protruding portion is formed by press-fitting which comes into contact with the flat surface of the chip, first, the length of the entire fitting portion becomes long. The displacement between the tip and the axis in the direction of each axis is reduced. The rear fitting portion prevents the chip from being displaced without applying a large outward deforming force to the shaft. In addition, the front fitting portion is not only sufficiently secured by a large fitting force, but also has no specific large contact force, so that the deformation of the shaft is uniform. For these reasons, concentricity and fixation can be sufficient.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing an example of the present invention, and FIG. 2 is a sectional view of an essential part showing another example. 1… small tube tip, 2… fine rod, 3… tip, 4…
... Temporary ink reservoir member, 5 ... Ink guiding member, 6 ...
... Axle, 7... 1st rib, 8... 2nd rib, 9... 3rd rib, 10... 4th rib, 11. 2 inward projection, 13 ... third inward projection, 14 ... projection base of the first inward projection, 15 ... projection base of the second inward projection, 16 ... Projection base of the inward projection of 3, 17 ... Inward projection, 18 ... Engagement step.

Claims (1)

(57) [Scope of request for utility model registration] 1. A pen for an automatic drafting machine in which a tip protruding a pen tip is fitted and fixed to a tip of a shaft, wherein the shaft is made of a synthetic resin softer than the tip. Is formed by a front fitting portion having a relatively large fitting force and a rear fitting portion having a relatively small fitting force. Further, the front fitting portion has an inwardly projecting portion formed on an inner wall of the shaft. A pen for an automatic drafting machine, which is formed by press-fitting in contact with the flat surface of a chip.