JP4648375B2 - Mechanical pen - Google Patents

Description

  The present invention relates to a mechanical pen, and more particularly to a mechanical pencil. For example, this type of pen known from Patent Document 1 has a substantially sleeve-shaped shaft provided with a tip portion, and serves to feed a core storage portion and a core in the axial direction inside the shaft. 2 and Patent Document 3 are known. The lead feeding unit includes a clamp device that can be operated by a pressing mechanism or a rotating mechanism that acts in the axial direction. A guide passage that communicates with the internal space of the shaft and serves to receive and guide the lead when the lead is moved out of the tip by the feed mechanism passes through the tip. Inside the shaft, a portion for holding the core by frictional coupling, a so-called core braking portion is arranged. The core braking part includes a cylindrical clamp body that has a hole extending in the axial direction and serves to hold the core by frictional coupling, and a sliding body that serves to guide the core braking part in the axial direction in the sliding region of the shaft. Including. The sliding body is configured and dimensioned so as to be slid in the axial direction when the sliding body is pressed in the radial direction toward the sliding region based on an elastic restoring force and an axial force is applied. For example, a core pipe protruding from the tip of the pen when the pen is used is connected to the sliding body of the core braking unit. Since the core braking portion is slidable in the axial direction, the core pipe can be pushed into the through hole by pressing against the underlay, for example. The clamp body is designed to hold the core with a frictional force smaller than the frictional force generated in the sliding region when the core braking portion and the sliding body slide in the axial direction.

The core braking part is usually injection-molded with plastic. In that case, a mold having a large number of molding cavities is used. The result alone already creates problems with the tolerances that occur in the finished product. In addition, tolerances due to the process are added to this. Lastly, since an error from the target dimension also occurs when the lead end and the sliding area are produced, the lead braking part is guided to the sliding area with an excessive or excessive frictional force depending on the tolerance situation. It will be. For this reason, the return movement of the core braking part with possibly connected core pipes may require different forces for each pen depending on the tolerance situation, which is not desirable.
German Patent Application Publication No. 19502779 German Patent No. 3915331 US Patent Application No. 4,896,982

  An object of the present invention based on the above is to provide a pen in which the above-described problems are solved.

  This problem is solved by a pen comprising the features of claim 1. The core braking portion includes a sliding body configured as a sliding ring, the sliding body surrounding the clamp body at a radial interval and clamping via a plurality of radial webs leaving the penetrations between each other On the outside of the wall segment of the sliding ring that is connected to the body and extends between two adjacent webs, a radially upstanding projection is arranged respectively. As already described at the beginning, the sliding body and the sliding ring having radial protrusions are enclosed in the sliding area of the pen shaft. As a result, the wall segment is pressed radially inward against the elastic return force and becomes flat in that case. And the error due to the tolerance of the sliding area of the pen and the sliding ring is compensated by the deformation and flattening of the wall segment which has a great influence to some extent, so that regardless of the situation of each tolerance, The axial sliding of the core braking part with an almost equal axial force is always guaranteed.

  Other advantageous embodiments are given in the dependent claims.

  Next, the present invention will be described in detail with reference to the accompanying drawings.

  As can be seen from FIG. 1, the pen 1 according to the present invention includes a shaft 1b, which has a tip 1a at its front end. There is a sliding area 3 inside the tip portion 1a, in which a core braking portion 4 formed as an integral plastic injection molded product is slidably arranged in the axial direction. The core braking part includes a substantially cylindrical clamp body 7, which has a central long axis and a hole 6 extending coaxially with the central long axis 16 of the core braking part, and the core pipe 8 is clamped. It is fitted on the body. Two axial slits 9 facing each other in diameter from the front end face 5 of the clamp body 7 are engraved in the clamp body. In this way, two holding tongues 10 that are diametrically opposed are formed, and each holding tongue supports a nep 12 protruding radially inward on each inner surface. When the lead is fed through the hole 6 by the feeding mechanism of the pen 1, the lead passes through the nep 12, and the holding tongue 10 expands in the radial direction accordingly, and the lead is frictionally coupled based on the elastic restoring force. Held by. The rear end portion of the clamp body 7 is coaxially surrounded by the sliding ring 13 with a gap in the radial direction. The sliding ring 13 is connected to the clamping body 7 via at least two, preferably three radial webs 14, which are distributed evenly over the entire circumference of the sliding ring 13. Yes. The outer surface 15 of the sliding ring 13 extends in a cylindrical shape and extends coaxially with the central long axis 16 of the clamp body 7 and the core braking portion 4. A longitudinal section 18 extending rearward from the front end face 17 of the sliding ring 13 has a wall thickness that is smaller than the second longitudinal section 20 that follows and extends towards the rear end face 19. A radial web 14 connecting the clamp body 7 with the sliding ring 13 is integrally formed on the inner wall 22 of the first longitudinal section 18. The axial length substantially corresponds to the axial length of the first longitudinal section 18. Since the ring 13 is fixed to the clamp body 7 via the web 14, the arc-shaped through portion 23 extends between the adjacent radial webs 14. On the outer surface 15 of the wall segment 24 extending between the two adjacent radial webs 14, protrusions 25 projecting outward in the radial direction are integrally formed. The protrusions 25 are evenly distributed over the entire circumference of the ring 13 as in the radial web 14, but are arranged at a location rotated by 45 ° with respect to the radial web, and are seen in the circumferential direction. It is positioned at the center of the segment. The axial length of the protrusion 25 substantially corresponds to the axial length of the ring 13. The protrusion 25 has a first taper surface 26 extending away from the front end surface 17, and a second taper surface 27 extending substantially to the rear end surface 19 of the ring 13. The taper surface has a larger axial length than the first taper surface 26. The first taper surface serves as an introduction slope when the core braking portion 4 is inserted into the sliding region 3.

  The sliding ring 13 is in contact with the inner wall 11 of the cylindrical sliding region 3 of the pen tip 1 at its three protrusions 25. The inner width of the protrusion 25 and the diameter of the virtual circumscribed circle surrounding the protrusion 25 are larger than the inner diameter of the sliding region 3, and as a result, the wall region 24 is pressed radially inward and flattened at that time. It becomes. In terms of the number of protrusions, in principle, at least two protrusions are required to guide the core braking part in the sliding area so as to be slidable in the axial direction and to support it at the center. However, the three-point support of the core braking part 4 by the three protrusions 25 evenly distributed in the circumferential direction is particularly preferable. The wall segment 24 supporting the protrusion 25 can be elastically deformed due to its small wall thickness. In the assembled state, the wall segment is slightly flattened and slightly pressed outward in the radial direction, so that the protrusion 25 is based on the restoring force acting in the radial direction, so that the inner wall 11 of the sliding region 3 is Pressed against. Based on the multi-point support and the preferred three-point support of the core braking part 4 in the sliding region 3, for example, an error from the circular shape of the sliding region 3 due to tolerance is compensated by the radial movement of the protrusion 25. The wick braking unit 4 can slide in the axial direction on the sliding region 3 with a substantially constant force even when the above-described situation exists. Furthermore, the centering of the core braking part 4 in the sliding area 3 is ensured by the three-point support. This is ensured particularly when the projections are in contact with the sliding area in a dot-like or linear manner. By further reducing the wall thickness of the partial region 31 (FIG. 12) of the wall segment 24a, it is possible to further improve the adaptability of the sliding body 5 to various tolerance situations, and this is the case with the three wall segments. One of 24 is shown in FIG. The partial region 31 can support the protrusion 25 or may be arranged in a state offset from the protrusion to the side. Due to the wedge shape of the projection 25 and the presence of both tapered surfaces 26, 27, the projection 25 is substantially only at the ridgeline 28 that connects both tapered surfaces 26, 27 to one another, ie linearly, the sliding region. 3 in contact with the inner wall 11.

  The rear area of the hole 6 that penetrates the clamp body 7 has a shape like an opening of a trumpet, for example, and is formed as a region 33 that expands in a substantially funnel shape. The funnel-shaped extension continues steplessly to the end face 29 on the rear side of the web 14. Since the rear hole area has a funnel shape, the core re-supplied to the pen mechanism can reach the hole 6 of the clamp body 7 without any problem.

  Due to the large wall thickness of the second longitudinal section 20 of the ring 13, the penetration 23 is narrowed in this longitudinal section, which is smaller than the diameter of the core used each time, for example 0.7 mm or The inner width 30 is smaller than 0.5 mm. The thinnest core normally used in knock-type mechanical pens has a diameter of 0.35 mm. Therefore, it is possible to prevent or at least make it difficult for the lead or the broken piece of the lead to pass through the penetrating part 23 and enter the movement track of the lead braking part 4. Such an intrusion leads to a malfunction of the core stockpile.

  In the longitudinal section 32 of the clamp body 7 extending away from the ring 13, an axial rib 32 with the core pipe 8 fitted is integrally formed (FIG. 1). The core pipe passes through the opening 34 of the distal end portion 1a, and has an outlet opening 35 at the front end thereof through which the core passes when in use. A radial flange 36 is integrally formed at the rear end portion of the core pipe 8 so as to hit the shoulder portion 37 extending substantially in the radial direction of the front end portion 1a from the rear. The diameter 38 of the exit opening 35 is slightly larger than the appropriate core size or core diameter for the pen. The aforementioned inner width 30 of the through-hole 23 is preferably smaller than the diameter 38 of the outlet opening 35 to prevent the passage of the core or the core fragments, and is smaller than the diameter of the core to be used each time. Good.

  In the situation shown in FIG. 1, the lead braking unit 4 holds a lead (not shown) so that the pen can be used with normal writing pressure. When not in use, the core pipe 8 protruding from the distal end portion 1a and the core protruding therefrom are obstructive. In order to deal with this point, the protruding core is first pushed back by pressing against the underlay. This is because the lead braking part 4 holds the lead with a force smaller than the force necessary to slide the lead braking part 4 in the axial direction in the sliding region 3. Finally, the core pipe 4 is also pushed back to the distal end portion 1a. By operating a feed mechanism (not shown) and displacing the core braking portion toward the tip portion 1a, the initial state shown in FIG. 1 can be realized again.

It is an axial direction sectional view showing the tip region of a knock type mechanical pencil. It is a perspective view which shows a core braking part. FIG. 3 is a perspective view of a core braking portion viewed from the back side and the direction of arrow III in FIG. 2. It is another perspective view of a core braking part. It is an axial section perspective view showing a core braking part. It is the top view seen from the direction of arrow VI of FIG. It is a side view which shows a core braking part. It is sectional drawing along the VIII-VIII line of FIG. It is the top view seen from the back surface of the core braking part and the direction of the arrow IX of FIG. FIG. 8 is an axial cross-sectional view along line XX in FIG. 7. It is the detail part XI of FIG. It is drawing corresponding to FIG. 6 which shows the core braking part by a modification.

Explanation of symbols

1 pen, 1a tip, 1b axis, 2 through hole, 3 sliding area, 4 core braking part, 5 end surface, 6 hole, 7 clamp body, 7a, 16 center long axis, 8 core pipe, 9 axial slit, 10 retaining tongue, 11, 22 inner wall, 12 nep, 13 sliding ring, 14 radial web, 15 outer surface, 17, 19, 24 end face, 18, 20 longitudinal section, 23 penetration, 24 wall segment, 25 protrusion 26, 27 Tapered surface, 28 Zenith edge, 30 Inner width, 31 Partial region, 32 Axial rib, 33 region, 34 Opening, 35 Outlet opening, 36 Radial flange, 37 Shoulder, 38 Diameter

Claims (10)

A mechanical pen comprising a lead feeding mechanism, a shaft (1b) provided with a tip (1a), and a lead braking part (4),
The core braking part can be displaced in the axial direction so that a part of the pen is protruding from the tip (1a) when the pen is used, and the core braking part has a hole (6) penetrating in the axial direction. a substantially cylindrical clamp body, which serves accommodating and fixing the core (7), contrast is expanded in the radial direction, the core damping in sliding area (3) of the pen (1) In a mechanical pen having a sliding body that serves to guide the part in the axial direction,
The sliding body is connected to the clamping body via a plurality of radial webs (14) surrounding the clamping body (7) with a radial spacing and leaving a penetration (23) between them. Protrusions (25) that are configured as sliding rings (13) and that stand radially on the wall segment (24) of the sliding ring (13), each extending between two adjacent webs. Mechanical pens that are arranged respectively.   The said sliding ring (13) comprises three radial webs (14) and three corresponding wall segments (24) and three projections (25). pen.   The pen according to claim 2, wherein at least one of the protrusions (25) is arranged in the center of the wall segment (24) when viewed in the circumferential direction.   The pen according to claim 2 or 3, characterized in that at least one of the protrusions (25) contacts the sliding area (3) in a dotted or linear manner.   The protrusion (25) has a tapered surface (26) extending away from the front end surface (17) of the sliding ring and tapering toward the tip (1). A pen according to one of 2 to 4.   The protrusion (25) has a second taper surface (27) that follows the first taper surface (26) and tapers toward the end surface on the rear side. 6. Pen according to claim 5, characterized in that the pens move to each other via a zenith edge (28) that extends into contact with the sliding area (3).   7. Pen according to one of claims 2 to 6, characterized in that at least one of the wall segments (24) has a partial area (31) with a small wall thickness.   The pen according to claim 7, characterized in that the partial area (31) supports one protrusion (25).   The penetrating part (23) has an inner width (30) smaller than the outlet opening part (35) at the tip part (1a) through which the core penetrates when in use when viewed in the radial direction. The pen according to claim 1.   2. The rear section of the hole (6) passing through the clamp body (7) in the axial direction extends substantially in a funnel shape towards the rear end of the pen. 9. The pen according to one of the nine.