JP5187079B2 - Ballpoint pen manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a ballpoint pen that regulates a backward movement of an elastic member that urges a ball as a writing member forward.

2. Description of the Related Art Conventionally, a coil spring fitted over a protrusion formed on an inner wall of a member that connects a ballpoint pen tip and an ink tank is known (see Patent Document 1).
JP 2002-127670 A

In the thing which the protrusion and the large-diameter portion of the elastic member which are disclosed in Patent Document 1 get over and are locked, the protrusion and the elastic member rub against each other when getting over, and either or both of the members are scraped. Or damage such as deformation. As a result, the backward biasing force against the elastic member is weakened, the pressing force of the ball is not constant, and there is a risk of causing variations in mass production. In addition, it cannot withstand the impact of using the product (impact when knocking back, impact when dropping the ballpoint pen), etc., and the elastic member will come off the protrusion, making it impossible to urge the ball forward. As a result, ink leakage from the pen tip could occur. In addition, the elastic member may come off from the protrusion due to an impact during manufacture (impact during transportation of parts, etc.), resulting in a defective product.
In particular, when a metal coil spring is used as an elastic body for urging the ball forward, the synthetic resin protrusion is easily damaged.

The present invention relates to a ball as a writing member, a ball holder that holds the ball partially protruding from a tip opening, an elastic member that urges the ball forward, and a thermoplastic synthetic that surrounds the elastic member A cylindrical member made of resin, and by melting the cylindrical member in a state where the ball is urged forward by an elastic member, an inward protrusion is formed in the inner hole of the cylindrical member, A gist of a ballpoint pen manufacturing method using the inward protrusion as a retraction restricting portion of the elastic member.

  Since the resin is melted in the state where the ball is urged forward to form the protrusion and the retraction restricting portion of the elastic member is created, the position of the elastic member relative to the ball can be easily managed, and the desired ball pressing force can be stably obtained. In addition, since the molten resin flows along the elastic member, the elastic member can be securely fixed.

  The ballpoint pen is obtained by connecting a ball holder that holds a ball as a writing member partially protruding from the tip opening and an ink tank. The connection between the ball holder and the ink tank can be directly press-fitted with each other, but a joint member can be interposed in order to fill the difference between the inner diameter and the outer diameter.

The ball serving as a writing member is disposed in the inner hole of the ball holder, and the ball holder forms an inner step part that regulates the retraction of the ball in the inner hole by cutting or rolling from the outside. Then, after the ball is installed, the diameter of the opening is reduced by, for example, caulking, and the ball is rotatably held in a state in which the ball is partially protruded from the tip opening.
After holding the ball, press the rear end of the ball directly or through another member with an elastic member that elastically urges the ball forward, and press the ball against the inner edge of the tip opening of the ball holder when not in use Thus, ink leakage from the portion is suppressed. During use, the ball is pressed against a writing surface such as paper, and the elastic member contracts to form a gap through which ink can flow out between the ball and the inner edge of the tip opening of the ball holder. When the ball is separated from the writing surface, the elastic member elastically recovers and the ball is again pressed against the inner edge of the tip opening of the ball holder to form a state in which ink does not flow out. In order for the elastic member to apply a pressing force to the ball, the elastic member needs to be installed so as to be retracted, and the elastic member is retracted into the inner hole of the ball holder inner hole or the ink tank connecting member. An inward projecting portion serving as a restricting portion is formed, and the elastic member is installed on the front side thereof.

In the present invention, as a cylindrical member, by applying ultrasonic waves to the connection member between the ball holder or the ball holder and the ink tank, the cylindrical member is melted and deformed to such an extent that the shape can be deformed. An inward protruding portion is formed. That is, after holding the ball rotatably in the ball holder, an elastic member is inserted from the rear end opening of the ball holder, and ultrasonic vibration is applied to the rear end opening of the ball holder so as to melt it inside. Push to form an inward protruding part or install an elastic member so that it is sandwiched between the ball holder and the ink tank connecting member, and then apply ultrasonic vibration from the rear end of the ball holder and ink tank connecting member. After applying and melting, push inward to form the inward protruding portion, or after assembling the ball holder and the connecting member, insert an elastic member from the rear end opening of the connecting member, and then connect the connecting member By applying ultrasonic vibration from the rear end and melting it, it is pushed inward to form an inward protruding portion, thereby making the elastic member receding restricted.
At this time, the elastic member is in a contracted state so that the ball comes into contact with the inner edge of the tip opening of the ball holder with sufficient force to suppress ink leakage (or another member when another member is interposed). And the inward projecting portion serving as the retraction restricting portion must be held between them. In the present invention, the inward protruding portion is formed in a state where the elastic member is pressed and contracted to apply a forward biasing force to the ball.

As a method of melting the resin in order to form the inward protruding portion, in addition to using ultrasonic vibration, melting by heat or softening by a solvent can be considered, but the influence on other members and local processing accuracy, From the ease of handling, it can be said that application of ultrasonic waves is preferable.
Moreover, the jig | tool which provides the ultrasonic vibration, heat, etc. which fuse resin may compress an elastic member simultaneously, and the member which compresses an elastic member may be provided separately.

The elastic member may be a metal or synthetic resin coil spring or rod-shaped member that can be reduced in length by an external force and restored when the external force is released. In particular, the part corresponding to the rear end of the ball is a small-diameter hole part in which an inner step part is formed in the ball holder to regulate the backward movement of the ball. It can be said that a coil spring made of an alloy such as stainless steel is preferable because of durability of use. However, this is not the case when another member is disposed between the elastic member and the ball. Further, it is also possible to form a straight portion that does not wind a wire around the tip of the coil spring and to be a portion that pushes the ball.
By forming the inward protruding portion with the molten resin, it is possible to restrict the retraction of the elastic member, and at the same time, it is possible to form a recess into which the molten resin flows into the side wall of the elastic material, thereby securely fixing the elastic member. When a coil spring is used, fixing is ensured by the molten resin flowing into the gaps or dents between the wires.
However, if a large amount of resin flows from the gaps between the coil spring lines, it will also fill the space through which the essential ink passes, so you should manage the amount of resin to be melted and the destination of the flow. is there. For example, in addition to minimizing the volume of the melted resin by managing the applied ultrasonic waves, it is also possible to form a resin flow barrier by an elastic member. In addition, a portion where the winding adjacent to the rear end of the coil spring is in contact (the so-called “end winding portion”) is arranged to prevent the molten resin from entering the inside of the coil spring. You can also

Hereinafter, an example will be described with reference to the drawings.
What was shown in FIG. 1 is an example of the ball-point pen produced using the manufacturing method of this invention. That is, as a simple configuration, the ink tank 3 that contains the ink 1 and the follower 2 that is a high-viscosity fluid that prevents backflow of the ink, the ball holder 5 that holds the ball 4 as a writing member, and the ball 4 forward The coil spring 6 is an elastic member to be urged, and the connection member 7 connects the ink tank 3 and the ball holder 5. The ballpoint pen shown in FIG. 1 can be gripped and written as it is, but the one shown in this figure is installed in an easily replaceable outer package (not shown). It is shown assuming what is called a refill. Such ballpoint pens called refills are housed in an exterior body that is easy to grip, and are provided with a delivery locking mechanism or the like on the exterior body, so that You can also

A method for manufacturing the above ballpoint pen will be described.
First, a ball holder for holding the ball is formed by cutting or rolling. A solid bar member cut to an appropriate length, or a pipe material that has been previously cut to an appropriate length into a blank material is used as a blank, and this is subjected to cutting and rolling to provide an outer shape, After adjusting the middle shape and setting the ball, the tip opening of the ball holder is subjected to diameter reduction processing such as caulking to prevent it from coming off, and the ball is rotatably held.
A method of manufacturing a ballpoint pen tip composed of a ball holder and a ball using a solid bar member can be obtained, for example, by a method described in JP-A-6-191190. This production method can be obtained, for example, by the method described in JP-A-9-123663. Of course, it may be obtained by means other than these methods.
A coil pen 6, an ink tank 3, and a connecting member 7 are assembled to a ball pen tip 8 that is a combination of a ball and a ball holder, and the ink tank 3 is filled with ink 1 and follower 2 to form a ballpoint pen.

  Hereinafter, a specific example of a fixing method of an elastic member (in the example, the coil spring 6) that urges the ball forward by inserting the tip into the ball holder inner hole, which is a characteristic part of the present invention, will be described.

The ball-point pen tip 8 and the connection member 7 between the ball-point pen tip 8 and the ink tank 3 are assembled so that the rear end of the ball holder 5 is press-fitted into the front opening 7 a of the connection member 7. To obtain a member A in which As shown in FIG. 2, this member A is installed in the inner hole 9 a of the support base 9 so that the ball 4 faces downward and the rear end of the ball holder 5 faces upward, and then the rear end opening of the connecting member 7. The coil spring 6 is inserted from the portion 7b. The coil spring 6 has a rod-shaped portion 6a that is formed in a straight line without winding on the front end side, and a counter-wound portion 6b that is in contact with a winding portion adjacent to the rear end, and the rod-shaped portion 6a. It arrange | positions so that the front-end | tip of may contact the rear end of the ball | bowl 4. FIG.

  As shown in FIG. 3, which is an enlarged view of the I part of FIG. 2, a pressing rod 10 for compressing the coil spring 6 is then inserted from the rear end opening 7 b of the connecting member 7, and moved downward to press the pressing rod. The tip of 10 is brought into contact with the rear end of the coil spring 6, and the pressing rod 10 is moved downward to compress the coil spring 6. The pressing bar 10 stops moving and maintains its position in a state where the elastic force of the compressed coil spring 6 urges the ball 4 forward.

Next, as shown in FIG. 4, a horn 11 for applying ultrasonic vibration is inserted from the rear end opening 7 b of the connection member 7.
The horn 11 has a cylindrical shape, the above-mentioned pressing rod 10 is disposed in the inner hole, and the pressing rod 10 and the horn 11 are movable back and forth with respect to each other. Further, the connecting member 7 has a portion having a smaller diameter than the outer diameter of the horn 11 in the inner hole, and a step portion 7c having a difference in diameter is formed. When the insertion of the horn 11 is advanced, the tip surface of the horn 11 comes into contact with the inner step portion 7 c of the connecting member 7. In this state, ultrasonic waves are applied to the horn 11 and simultaneously the horn 11 is moved downward. The resin material in the vicinity of the stepped portion 7c of the connecting member 7 is melted by the vibration energy generated by the ultrasonic waves, and the molten resin is pressurized by the downward movement of the horn 11 to spread the molten resin inward of the connecting member 7 (FIG. 5). Since the end portion 6b of the coil spring 6 is present before the molten resin spreads, the molten resin does not flow inward from the end winding portion 6b, and the molten resin flows into the recess 6c between the lines along the side surface of the end wound portion 6b. Infiltrate.
Application of ultrasonic waves in a state where the molten resin has reached a desired position, after the molten resin is solidified in a few seconds, the horn and the pressing rod are pulled out, and the coil spring 6 is fixed by the inward protruding portion 7d (See FIG. 6).
After the rear end of the connecting member 7 is press-fitted into the ink tank 3 described above, the ink 1 and the follower 2 which is a high-viscosity fluid that prevents backflow of the ink are filled, and then remains in the ink or the follower by applying centrifugal force. The removed bubble is removed to obtain the ballpoint pen shown in FIG. The ink 1 and the follower 2 may be connected to the member A by filling the ink tank 3 in advance.

Another example is shown in FIGS.
The method of fixing the coil spring 6 is different from the above-described example, and the assembly of the ballpoint pen tip 8 and the connection member, the installation of the member on the support base, the arrangement of the coil spring 6 and the backward movement restriction of the coil spring 6 are performed. The ball-point pen assembly method after the inward projection 7d is formed is the same as the above-described example. 7 to 9 are shown as drawings corresponding to the enlarged view of the portion I in FIG.

As shown in FIG. 7, the coil spring 6 in this example has a large-diameter portion 6c in the end winding portion 6b, and the connection member 7 has an outer diameter of the end winding portion 6b of the coil spring 6 on the inner wall. A circumferential convex portion 7e having a slightly smaller diameter is formed.
As shown in FIG. 8, the inserted coil spring 6 is pressed by the pressing rod 10, and the large-diameter portion 6d of the end winding portion 6b gets over the circumferential convex portion 7e. The position of the circumferential projection 7e is such that the coil spring 6 is compressed between the ball 4 and the circumferential projection 7e.
Next, as shown in FIG. 9, after removing the pressing rod 10, the horn 11 is inserted, ultrasonic vibration is applied while pressing the step 7c of the connecting member 7, and the resin near the step 7c is removed. The melted resin is inserted between the coil spring 6 and the horn 11, and the resin is solidified to fix the coil spring 6. In this example, since the thing which has the shape which has the protrusion part 11a at the front-end | tip part of the horn 11 was employ | adopted, molten resin does not penetrate | invade center direction beyond this protrusion part 11a, and secures the inner hole used as an ink channel | path. It can be said that it is preferable in the above. The point that the molten resin enters the concave portion 6c of the end winding portion 6b of the coil spring 6 and the fixing is ensured is similar to the above example.

  FIG. 10 shows still another example in which the fixing method of the coil spring 6 is different. As in the example of FIGS. 7 to 9, an inward projection 7 d for assembling the ball-point pen tip 8 and the connection member, placing the member on the support base, arranging the coil spring, and regulating the retraction of the coil spring 6 is formed. The subsequent ballpoint pen assembling method is the same as the example shown in FIGS. FIG. 10 is also shown as a drawing corresponding to the enlarged view of the portion I in FIG.

  As shown in FIG. 10, the horn 11 is inserted from the rear end opening 7b of the connecting member 7, and the horn 11 is moved downward to compress the coil spring 6 at the front end surface of the horn 11, and at the same time, the horn. 11 is brought into contact with the inner step portion 7c of the connecting member 7. In this example, since the horn 11 has a shape having a recess 11b at the tip, the rear end of the coil spring 6 enters the inside of the recess 11b at the tip of the horn 11, so It can be said that the end is not shifted to the side, which is preferable in suppressing variation in the ball pressing force by the coil spring 6. Ultrasonic vibration is applied while pressing the step 7c of the connecting member 7 with the horn 11, the resin in the vicinity of the step 7c is melted, and the molten resin enters between the coil spring 6 and the horn 11 to solidify the resin. To fix the coil spring 6. The point that the molten resin enters the concave portion 6c of the end winding portion 6b of the coil spring 6 and the fixing is ensured is similar to the above example.

  FIG. 11 shows still another example in which the fixing method of the coil spring 6 is different. As in the example of FIGS. 7 to 9, the ball-point pen after the inward projection for assembling the ball-point pen tip and the connecting member, placing the member on the support base, arranging the coil spring, and restricting the coil spring to retreat is formed. The assembly method is the same as the example shown in FIGS. The compression operation of the coil spring by the horn and the melting of the resin by the horn are the same as the example shown in FIGS. Note that FIG. 11 is also shown as a drawing corresponding to the enlarged view of the portion I in FIG.

  As shown in FIG. 11, in this example, the horn 11 is formed with a protruding portion 11 a and a recessed portion 11 b surrounding the protruding portion 11 a at the tip, and an inclined surface 11 c that reduces the diameter of the protruding portion 11 a toward the tip. It was supposed to have. And since the front-end | tip of the projection part 11a was made into the magnitude | size inserted inside from the rear end of the coil spring 6, the inclined surface 11c of the projection part 11a will contact | abut to the comparatively inner surface of the coil spring 6. FIG. Thereby, the molten resin can be arranged at the rear end of the coil spring 6. Further, since the molten resin also flows into the circumferential recess 11b formed at the tip of the horn 11, the thickness of the resin disposed at the rear end of the coil spring 6 is increased, and the strength of the retreat restricting portion is ensured. Will be.

Ballpoint pen made using the manufacturing method of the present invention The longitudinal cross-sectional view which shows an example. The principal part enlarged view of FIG. FIG. 3 is a view corresponding to FIG. FIG. 3 is a view corresponding to FIG. FIG. 3 is a view corresponding to FIG. The figure corresponding to FIG. 3 which shows another example. The figure corresponding to FIG. 3 which shows another example. The figure corresponding to FIG. 3 which shows another example. FIG. 3 is a view corresponding to FIG. FIG. 3 is a view corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ink 2 Followers 3 Ink tank 4 Ball 5 Ball holder 6 Coil spring 7 Connection cylinder member 8 Ball-point pen tip 9 Support base 10 Press rod 11 Horn

Claims (1)

A ball as a writing member, a ball holder that holds the ball by partially protruding from the tip opening, an elastic member that urges the ball forward, and a cylinder made of thermoplastic synthetic resin that surrounds the elastic member And forming an inward protrusion in the inner hole of the cylindrical member by melting the cylindrical member in a state where the ball is urged forward by the elastic member. A method of manufacturing a ballpoint pen using the elastic member as a retraction restricting portion.