JP2016221788A - Ball point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball point pen which can stabilize contact between a ball rear surface and a retainer, adequately press a center of the ball rear surface forward when the pen is not used, and obtain smooth rotation of a ball when the pen is used.SOLUTION: In a ball point pen, a spring 5 that urges a ball 4 forward and makes the ball 4 closely contacted with an inner face of a front end edge part 31 is arranged at the rear side of a ball 4. The spring 5 comprises: a coil part 52 which is formed by being wound multiple times; and a rod part 51 which is integrally connected with the coil part at a front end portion of the coil 52. A receiving part 6 having a concave surface 61 at the front face is arranged at the front end of the rod part 51. The concave surface 61 contacts with the rear face of the ball 4. The outer diameter of the receiving part 6 is larger than that of the rod part 51.SELECTED DRAWING: Figure 3

Description

The present invention relates to a ballpoint pen.

Conventionally, in this kind of ballpoint pen, Patent Document 1 discloses that an inward tip edge is provided at the tip of the tip body, a ball receiving seat is provided on the inner wall near the tip of the tip body behind the tip edge, and the tip edge A ball is rotatably held between a portion and the ball receiving seat, a spring provided with a rod portion is provided behind the ball, and the tip of the rod portion presses the rear surface of the ball forward, It is a ballpoint pen for bringing the ball into intimate contact with the inner surface of the tip edge portion, and it is disclosed that a ring-shaped receiving portion in contact with the rear surface of the ball is integrally connected to the tip of the rod portion.

JP 2003-266985 A

The ballpoint pen of Patent Document 1 may not properly contact the rear surface of the ball in a ring shape due to manufacturing variations, and may not be able to properly press the center of the rear surface of the ball forward with the rod portion of the spring when not writing.

In the ballpoint pen of Patent Document 1, when the ball moves in the radial direction from the axial center at the time of writing, the contact between the rear surface of the ball and the seat becomes unstable, and there is a possibility that smooth rotation of the ball cannot be obtained.

The present invention solves the above-mentioned conventional problems, stabilizes the contact between the rear surface of the ball and the receiving portion, can properly press the center of the rear surface of the ball forward when not writing, and is smooth when writing A ballpoint pen capable of obtaining the rotation of is provided.

In the present invention, “front” refers to the chip body side, and “rear” refers to the opposite side.

In the present invention, a front end edge portion 31 is provided inwardly at the front end of the chip body 3, a ball receiving seat 32 is provided on the inner surface near the front end of the chip body 3 behind the front end edge portion 31, and the front end edge portion 31 and the A spring that rotatably holds the ball 4 with respect to the ball receiving seat 32, urges the ball 4 forward, and closes the ball 4 to the inner surface of the front end edge 31. 5, wherein the spring 5 includes a coil portion 52 formed by a plurality of windings, and a rod portion 51 integrally connected to a front end portion of the coil portion 52. A receiving portion 6 having a concave curved surface 61 on the front surface is provided at the front end of the portion 51, the concave curved surface 61 is brought into contact with the rear surface of the ball 4, and the outer diameter of the receiving portion 6 is set to the outer diameter of the rod portion 51. It is a requirement that it is set larger.

The ballpoint pen 1 of the first invention of the present application is provided with a receiving portion 6 having a concave curved surface 61 on the front surface at the front end of the rod portion 51, the concave curved surface 61 is brought into contact with the rear surface of the ball 4, By setting the outer diameter of the portion 6 to be larger than the outer diameter of the rod portion 51, the contact state between the concave curved surface 61 and the rear surface of the ball 4 can always be maintained stably, and the center of the rear surface of the ball 4 can be maintained when not writing. Can be properly pushed forward, and smooth rotation of the ball 4 can be obtained during writing.

The second invention of the present application requires that the outer diameter of the receiving portion 6 is set smaller than twice the outer diameter of the rod portion 51 in the ballpoint pen 1 of the first invention.

In the ballpoint pen 1 of the second invention, the outer diameter of the receiving portion 6 is set to be smaller than twice the outer diameter of the rod portion 51, whereby sufficient durability of the receiving portion 6 is obtained and the receiving portion 6 can be formed easily.

According to the ballpoint pen of the present invention, the contact between the rear surface of the ball and the receiving portion can be stabilized, the center of the rear surface of the ball can be properly pushed forward during non-writing, and smooth ball rotation can be obtained during writing.

It is a longitudinal cross-sectional view of embodiment of this invention. It is a principal part expanded longitudinal cross-sectional view of FIG. FIG. 3 is an enlarged vertical sectional view of a main part of FIG. 2. FIG. 3 is a front view of the spring of FIG. 2.

1 to 4 show an embodiment of the present invention.

Ballpoint pen The ballpoint pen 1 of the present embodiment includes a ballpoint pen tip 2 that rotatably holds a ball 4 at a front end, a holder 8 in which a rear portion of the ballpoint pen tip 2 is press-fitted and fixed to a front portion 81, and the holder An ink storage cylinder 7 in which a rear portion 83 is press-fitted and fixed to a front end opening thereof, a spring 5 accommodated in the inside of the chip body 3 and the holder 8, and a rear end opening of the ink storage cylinder 7 And a tail plug 9 which is press-fitted and fixed to. The tail plug 9 has a vent hole that allows the inside of the ink containing cylinder 7 to communicate with the outside air.

Ballpoint pen tip The ballpoint pen tip 2 comprises a tip body 3 and a ball 4. The chip body 3 is made of a cylindrical metal cylinder. The metal cylinder is obtained, for example, from austenitic stainless steel such as SUS304, SUS305, or SUS321. A plurality of (for example, four) inner protrusions are formed at equal intervals in the circumferential direction on the inner surface in the vicinity of the front end of the chip body 3 due to inward deformation. A ball receiving seat 32 is formed by the inward projection. Further, an inward front end edge 31 is formed at the front end of the chip body 3 by being pressed and deformed inwardly in a circumferential shape. A ball 4 is rotatably held between the front surface of the ball receiving seat 32 and the rear surface of the front end edge portion 31. Between the inward protrusions, there is formed an ink circulation hole 33 extending radially outward from the center and penetrating in the axial direction. That is, the ink circulation hole 33 is formed in the ball receiving seat 32. The ball receiving seat 32 may be formed on the inner surface of the metal chip body 3 by cutting, in addition to a configuration including a plurality of inward projections by inward deformation.

The ball 4 has a diameter in the range of 0.3 mm to 0.7 mm (preferably 0.3 mm to 0.5 mm).

Holder The holder 8 is a cylindrical body obtained by injection molding of synthetic resin (for example, polypropylene). The holder 8 includes a tapered front portion 81 to which the ballpoint pen tip 2 is attached, a collar portion 82 that contacts the front end surface of the ink containing cylinder 7, and a rear portion 83 that is press-fitted into the front end opening of the ink containing cylinder 7. Become. On the inner surface of the holder 8, a locking wall portion 8 a made up of an annular protrusion or a plurality of protrusions arranged in a circumferential manner is integrally formed.

Ink storage cylinder The ink storage cylinder 7 is a cylindrical body that is obtained by extrusion molding of a synthetic resin (for example, polypropylene) and is open at both ends. The ink container 7 is filled with an ink 71 and a follower 72 made of a highly viscous fluid that moves forward as the ink 71 is consumed. Examples of the ink 71 include low-viscosity aqueous or oil-based inks and aqueous or oil-based gel inks having shear thinning viscosity. Examples of the follower 72 include a configuration made of only a high-viscosity fluid, or a configuration in which a solid is contained in a high-viscosity fluid.

Spring The spring 5 includes a rod portion 51 that extends straight in the axial direction, and a coil portion 52 that is connected to the rear end of the rod portion 51 and formed by a plurality of spiral turns. The rod portion 51 and the coil portion 52 are integrally connected by a single metal wire (for example, a stainless steel wire). At the front end of the rod portion 51, a receiving portion 6 bulging in a radial direction in a dish shape or a cup shape is integrally formed. A spherical concave surface 61 is formed on the front surface of the receiving portion 6. The curvature radius of the concave curved surface 61 is set to be substantially the same as the curvature radius of the ball 4 or slightly larger than the curvature radius of the ball 4. Accordingly, a stable contact state between the concave curved surface 61 on the front surface of the receiving portion 6 and the rear surface of the ball 4 is maintained. In addition, a convex curved surface is formed on the rear surface of the receiving portion 6, thereby enabling a smooth ink supply to the ball 4 during writing.

The receiving part 6 is formed at the front end of the rod part 51 made of a metal wire by plastic deformation or melting. Thereby, the receiving part 6 which contacts the rear surface of the ball 4 can be freely formed in a desired size at the front end of the rod part 51 of the spring 5 without being influenced by the outer diameter of the applied wire.

A bulging portion 53 having an outer diameter larger than the outer diameter of the coil portion 52 is integrally formed at the rear end of the coil portion 52. The bulging portion 53 is locked to the locking wall portion 8 a on the inner surface of the holder 8.

The outer diameter of the receiving portion 6 is set smaller than the ball 4 and larger than the outer diameter of the rod portion 51. Further, the outer diameter of the receiving portion 6 is set smaller than the inner diameter of the ink circulation hole 33 (the diameter of the virtual inscribed circle at the top of the inward protrusion). The outer diameter of the receiving portion 6 is set smaller than twice the rod outer diameter.

In the ballpoint pen 1 of the present embodiment, a receiving portion 6 having a concave curved surface 61 on the front surface is provided at the front end of the rod portion 51, and the concave curved surface 61 is brought into contact with the rear surface of the ball 4. Is set larger than the outer diameter of the rod portion 51 so that the contact state between the concave curved surface 61 and the rear surface of the ball 4 can be constantly maintained stably, and the center of the rear surface of the ball 4 is properly maintained when not writing. The ball 4 can be pushed forward and a smooth rotation of the ball 4 can be obtained during writing.

In the ballpoint pen 1 according to the present embodiment, the outer diameter of the receiving portion 6 is set to be smaller than twice the outer diameter of the rod portion 51, so that sufficient durability of the receiving portion 6 is obtained and the receiving portion 6 Can be easily formed.

1 Ballpoint pen 2 Ballpoint pen tip
3 Chip body 31 Front edge 32 Ball seat (inward projection)
33 Ink distribution hole 4 Ball 5 Spring 51 Rod part 52 Coil part 53 Swelling part 6 Receiving part 61 Recessed curved surface 7 Ink receiving cylinder 71 Ink 72 Follower 8 Holder 8a Locking wall part 81 Front part 82 Hang part 83 Rear part 9 plug

Claims (2)

A front edge is provided inwardly at the front end of the chip body, a ball receiving seat is provided on the inner surface near the front end of the chip body behind the front edge, and the ball is rotated between the front edge and the ball receiving seat. A ballpoint pen provided with a spring that can be held and urged forward of the ball and in close contact with the inner surface of the front end edge portion.
The spring includes a coil portion formed by a plurality of windings and a rod portion integrally connected to a front end portion of the coil portion, and a receiver provided with a concave curved surface at the front end of the rod portion. A ballpoint pen characterized in that a concave portion is provided, the concave curved surface is brought into contact with the rear surface of the ball, and an outer diameter of the receiving portion is set larger than an outer diameter of the rod portion. The ballpoint pen according to claim 1, wherein an outer diameter of the receiving portion is set smaller than twice an outer diameter of the rod portion.

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