JP2012091466A - Ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-point pen which can prepare a backflow preventing mechanism by a simple manufacturing process.SOLUTION: A ball 21 is rotationably held at a front end of a tip body 2 by a front end edge 22 of inward-looking, and two or more internal protrusions 23 for ball receiving seats formed by pressing deformation to an internal direction behind the front end edge 22. A mounting hole 32 into which a tip body 2 is pressed is formed at an inner surface of a front end section of a holder 3. An annular stepped part 31 is formed in an inner surface of the holder 3 at a backside from the mounting hole 32. The backflow preventing mechanism 4 includes: a ball valve 41 which is movably back and forth held behind the internal protrusions 23 in the tip body 2; a regulation part 42 which is formed in a rear face of the internal protrusions 23, and regulates a forward movement of the ball valve 41 at the time of a pen point facing down; and a valve seat section 43 which is formed at a front surface of the annular stepped part 31, and to which the ball valve 41 can be close annularly with the pen point facing upward.

Description

The present invention relates to a ballpoint pen. More specifically, the present invention relates to a ballpoint pen that includes a tip body that holds a ball rotatably at the front end and includes a backflow prevention mechanism inside, and a holder that press-fits the rear outer surface of the tip body.

Conventionally, in this type of ballpoint pen, for example, in Patent Document 1, an inward protruding portion is provided by pressing and deforming a plurality of locations near the rear end of the ballpoint pen tip from the outside, and the rear end portion of the ballpoint pen tip is directed inward. A configuration is disclosed in which a back end crimping portion is formed by caulking, a backflow prevention ball is inserted between the inward protruding portion and the rear end caulking portion, and a backflow prevention mechanism is provided in the chip body.

JP 2007-313818 A

In the conventional ballpoint pen, in order to provide a backflow prevention mechanism in the chip body, a pressing deformation process in which an inward protruding portion is formed in the vicinity of the rear end of the chip body, and a rear end crimp in the rear end of the chip body are formed. Since the processing is required, the manufacturing process becomes complicated, leading to an increase in cost.

The present invention solves the above-mentioned conventional problems, and is intended to provide a ballpoint pen that can be provided with a backflow prevention mechanism with a simple manufacturing process and can suppress an increase in cost.

<1> The first invention of the present application is that a chip body 2 having a ball 21 rotatably held at the front end and provided with a backflow prevention mechanism 4 therein, and a holder 3 for press-fitting and holding the rear outer surface of the chip body 2 A ballpoint pen comprising: an inward front end edge 22 at the front end of the chip body 2; and a plurality of inner parts for a ball receiving seat formed by inward pressing deformation behind the front end edge 22 A ball 21 is rotatably held by the projection 23, and an attachment hole 32 into which the chip body 2 is press-fitted is provided on the inner surface of the front end portion of the holder 3, and the holder 3 behind the attachment hole 32 is provided. An annular step 31 having an ink circulation hole 33 is formed on the inner surface, and the backflow prevention mechanism 4 is accommodated so as to be movable back and forth behind the inward projection 23 in the chip body 2; Formed on the rear surface of the inward projection 23, A restricting portion 42 that restricts the forward movement of the ball valve 41 when the tip is downward, and a valve seat 43 that is formed on the front surface of the annular step portion 31 so that the ball valve 41 can be in close contact with the annular shape when the pen tip is upward. It is necessary to become.

In the ballpoint pen 1 of the first invention, the backflow prevention mechanism 4 is formed on the rear surface of the inner protrusion 23 and the ball valve 41 accommodated so as to be movable back and forth behind the inner protrusion 23 in the chip body 2. A restriction portion 42 for restricting forward movement of the ball valve 41 when the pen tip is downward, and a valve seat portion 43 formed on the front surface of the annular step portion 31 so that the ball valve 41 can be in close contact with the ring shape when the pen tip is upward. Therefore, special pressing deformation processing and caulking processing only for providing the restriction portion 42 and the valve seat portion 43 of the backflow prevention mechanism 4 in the chip body 2 are not required, and the backflow prevention mechanism is achieved with a simple manufacturing process. 4 can be provided. As a result, an increase in manufacturing cost can be suppressed.

<2> According to a second invention of the present application, in the ballpoint pen 1 of the first invention, the diameter of the ball valve 41 is larger than the diameter of a virtual inscribed circle in contact with the apex of the inward projection 23, and It is a requirement that it is set smaller than the inner diameter of the chip body 2 behind the inner protrusion 23 and larger than the inner diameter of the annular step portion 31.

In the ballpoint pen 1 according to the second aspect of the present invention, the ball valve 41 has a diameter that is larger than the diameter of a virtual inscribed circle that is in contact with the apex of the inward projection 23, so that the ball moved forward on the rear surface of the inward projection 23. The restricting portion 42 with which the valve 41 can come into contact can be reliably formed. In the ballpoint pen 1 of the second invention, the ball valve 41 is reliably moved within the tip body 2 by setting the diameter of the ball valve 41 to be smaller than the inner diameter of the tip body 2 behind the inner protrusion 23. Can be made. In the ballpoint pen 1 of the second invention, the diameter of the ball valve 41 is set to be larger than the inner diameter of the annular step portion 31, so that the valve seat portion 43 to which the ball valve 41 moved rearward can be intimately formed is reliably formed. can do.

In the present invention, the ball valve 41 is preferably set slightly smaller than the ball 21 at the nib. Thereby, the ball valve 41 can smoothly move in the chip body 2 behind the inward projection 23.

In the present invention, the specific gravity of the ball valve 41 is set larger than the specific gravity of the ink. As a result, the ball valve 41 can be reliably lowered by gravity according to the vertical direction of the pen tip, and a large ink flow path can be secured.

The ballpoint pen of the present invention can be provided with a backflow prevention mechanism with a simple manufacturing process.

It is a principal part expansion longitudinal cross-sectional view at the time of pen point downward of the 1st Embodiment of this invention. FIG. 2 is an enlarged vertical sectional view of a main part when the pen tip of FIG. It is a longitudinal cross-sectional view at the time of pen point downward of the 1st Embodiment of this invention.

1 to 3 show an embodiment of the present invention.
The ball-point pen 1 of the present embodiment includes a chip body 2, a holder 3 to which the outer surface of the rear end portion of the chip body 2 is press-fitted and fixed, and an ink storage tube 5 to which the rear end portion of the holder 3 is press-fitted and fixed. Become. An ink 51 and a follower 52 (for example, a high-viscosity fluid) that moves forward as the ink 51 is consumed are accommodated in the ink storage tube 5. In the present embodiment, the holder 3 and the ink storage tube 5 are configured as separate members. However, the holder 3 and the ink storage tube 5 may be configured as a single member integrally provided.

The chip body 2 is formed of a metal (for example, stainless steel) cylinder having a ball 21 rotatably held at a front end. An inward front end edge portion 22 is formed at the front end of the chip body 2 by annular pressing deformation. A plurality of (for example, three or four) inward projections 23 are formed in the vicinity of the front end of the chip body 2 (behind the front end edge portion 22) by inward pressure deformation. The front surface of the inward projection 23 serves as a ball receiving seat 23a. A pen tip ball 21 is rotatably held between the front edge 22 and the front surface of the inward projection 23.

A mounting hole 32 extending in the axial direction and an ink circulation hole 33 communicating with the mounting hole 32 are formed on the inner surface of the front end portion of the holder 3. An annular step 31 is integrally formed on the inner surface of the holder 3 (the inner surface of the ink circulation hole 33) behind the mounting hole 32.

Backflow prevention mechanism A backflow prevention mechanism 4 is provided inside the chip body 2. The backflow prevention mechanism 4 includes a ball valve 41 that is housed movably back and forth behind the inward projection 23 in the chip body 2 and a ball valve formed on the rear surface of the inward projection 23 when the pen tip is downward. A regulating portion 42 that regulates the forward movement of the valve 41 and an inclined valve seat 43 that is formed on the front surface of the annular step portion 31 so that the ball valve 41 can be in close contact with the ring when the pen tip is upward.

In the ballpoint pen 1 of the present embodiment, when the pen tip is downward, the ball valve 41 moves forward (moves downward), the ball valve 41 is brought into contact with a restricting portion 42 including a plurality of inward projections 23, and the ball valve 41 Forward movement is prevented. Since the restricting portion 42 includes a plurality of inward protrusions 23, the ink in the chip body 2 can be reliably supplied to the pen tip ball 21 through the ink flow gap between the inward protrusions 23. In the ballpoint pen 1 of the present embodiment, when the pen tip is upward, the ball valve 41 moves backward (moves downward), the ball valve 41 is annularly brought into close contact with the valve seat 43, and the backflow of ink is prevented.

In the ballpoint pen 1 of the present embodiment, the backflow prevention mechanism 4 is formed on the rear surface of the inner protrusion 23, and the ball valve 41 accommodated in the tip body 2 so as to be movable back and forth behind the inner protrusion 23. A restricting portion 42 for restricting the forward movement of the ball valve 41 when the pen tip is downward, and a valve seat portion 43 formed on the front surface of the annular step portion 31 so that the ball valve 41 can be in close contact with the annular shape when the pen tip is upward. As a result, there is no need for special pressing deformation processing or caulking processing only for providing the regulating portion 42 and the valve seat portion 43 of the backflow prevention mechanism 4 in the chip body 2, and backflow prevention is achieved with a simple manufacturing process. A mechanism 4 can be provided. As a result, an increase in cost can be suppressed.

In the ballpoint pen 1 of the present embodiment, the diameter of the ball valve 41 is set larger than the diameter of a virtual inscribed circle that is in contact with the apex of the inward projection 23. As a result, the restricting portion 42 with which the ball valve 41 moved forward on the rear surface of the inward projection 23 can be reliably formed.

In the ballpoint pen 1 of the present embodiment, the diameter of the ball valve 41 is set smaller than the inner diameter of the tip body 2 behind the inward projection 23. Thereby, the ball valve 41 can be reliably moved inside the chip body 2.

In the ballpoint pen 1 of the present embodiment, the diameter of the ball valve 41 is set larger than the inner diameter of the annular step portion 31 of the ink circulation hole 33. Thereby, the valve seat part 43 with which the ball valve 41 moved rearward can be intimately formed can be reliably formed.

In the ballpoint pen 1 of the present embodiment, the specific gravity of the ball valve 41 is set larger than the specific gravity of the ink 51. Specifically, the ball valve 41 is made of metal or ceramic.

DESCRIPTION OF SYMBOLS 1 Ball-point pen 2 Tip body 21 Ball 22 Front end edge part 23 Inward protrusion 23a Ball receiving seat 3 Holder 31 Annular step part 32 Mounting hole 33 Ink flow hole 4 Backflow prevention mechanism 41 Ball valve 42 Restriction part 43 Valve seat part 5 Ink receiving pipe 51 Ink 52 Follower

Claims (2)

A ballpoint pen comprising a tip body that holds a ball rotatably at the front end and has a backflow prevention mechanism inside, and a holder that press-fits and holds the rear outer surface of the tip body,
At the front end of the chip body, a ball is rotatably held by an inward front end edge portion and a plurality of inward projections for a ball receiving seat formed by inward pressing deformation behind the front end edge portion. An attachment hole into which the chip body is press-fitted is provided on the inner surface of the front end portion of the holder, and an annular step is formed on the inner surface of the holder behind the attachment hole. A ball valve accommodated movably back and forth behind the inner projection, a regulating portion formed on the rear surface of the inner projection for regulating forward movement of the ball valve when the pen tip is downward, and the annular step portion A ball-point pen comprising: a valve seat formed on the front surface of the valve, wherein the ball valve is annularly closeable when the pen tip is upward. The diameter of the ball valve is larger than the diameter of a virtual inscribed circle in contact with the apex of the inward projection, smaller than the inner diameter of the tip body behind the inward projection, and larger than the inner diameter of the annular step portion. The ballpoint pen according to claim 1 set.

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