JPS623258Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a structure for securing the tip and tail plug of a writing instrument.

For example, in a lock-type ballpoint pen, the ballpoint refill housed inside the barrel is biased backwards by a coil spring, and the pen body is moved out and out by clicking the lock button.In this way, a coil spring cannot be used in a writing instrument. many. Also, normally a tip and a tail plug are fixed to both ends of the barrel, but since these need to be removed for purposes such as replacing the refill, they are often screwed onto the barrel. Therefore, threads must be formed on the inner surfaces of both ends of the barrel, the tail plug, and the outer surface of the tip. However, if the barrel is a thin metal pipe, it is difficult to form the threads, and the manufacturing process increases accordingly. increases. On the other hand, there is a risk that the coil spring built into the shaft cylinder will be powdered if it falls off when disassembled to replace the refill, etc., so it is desirable that the coil spring be fixed to another member.

The present invention was developed in view of these circumstances, and is a writing instrument with a simple structure in which the tip and tail plug can be screwed onto the end of the barrel, and the coil spring does not fall off when disassembled. The purpose is to provide a fixing structure for the tip and tail plug. The purpose of this is to press fit the large diameter part of a two-step diameter coil spring, the outer diameter of which is slightly larger than the inner diameter of the shaft cylinder made of a cylindrical pipe, into the end of the shaft cylinder to form a threaded groove, and then The spring is characterized in that it presses and biases an interior member such as a ballpoint pen refill at the spring, and a tip and a tail plug with a spiral groove are screwed into the large diameter part of the spring and are removably screwed together. This is achieved by the fixed structure of the tip and tail plug of the writing instrument.

The present invention will be specifically described below based on embodiments shown in the drawings.

FIG. 1 shows the first embodiment, which is a click-type ballpoint pen in which a ballpoint pen refill 2 is movable back and forth in a barrel 1 made of a thin metal cylindrical pipe. As a result, the pen body 2a protrudes and retracts from the tip opening of the tip 3. Reference numeral 4 denotes a two-step diameter coil spring consisting of a large diameter portion 4a and a small diameter portion 4b, and the large diameter portion 4 in a free state.
The outer diameter of a is slightly larger than the inner diameter of the shaft cylinder 1. The spring 4 has a large diameter part 4a press-fitted into the tip of the barrel 1 with the small diameter part 4b inward, and the tip of the small diameter part 4b comes into contact with the ballpoint pen reflector 2, which is an interior member, and is attached to the rear. This urging force causes the pen body 4a to sink into the tip 3.
Next, there is a pitch on the outer periphery of the fitting part of the tip 3 in the large diameter part 4.
A spiral groove equivalent to that of a is formed, and on the other hand, the large diameter portion 4a is press-fitted into the inner surface of the tip of the shaft cylinder 1, and the large diameter portion 4a constitutes a screw, so that the tip 3 is It can be screwed onto the large diameter portion 4a and is screwed and fixed.

FIG. 2 shows a second embodiment, in which a tip 3 is provided at the tip of the shaft tube 1, which is also made of a thin metal cylindrical pipe.
is fitted, a ballpoint pen refill 2, which is an interior member, is built into the barrel 1, and the pen body 2a is attached to the tip 3.
It protrudes from the opening at the tip. In this embodiment, the large diameter portion 4a of the two-stage diameter coil spring 4 is connected to the shaft tube 1.
It is press-fitted from the rear end, and the tip of the large diameter portion 4b presses the rear end surface of the ballpoint pen reflex reel 2, urging it forward. Therefore, the tapered part at the front of the ballpoint pen reflex 2 firmly contacts the tapered part inside the tip 3, and the amount of protrusion of the pen body 2a from the tip 3 is regulated to be constant. Since the contact portion is airtight, the pen body 2a can be hermetically sealed in an airtight space when a cap (not shown) is fitted when not in use. A spiral groove equal to the pitch of the large diameter portion 4a is formed on the outer periphery of the fitting portion of the tail plug 6, and is screwed in the same manner as the tip 3 of the first embodiment.

As explained above, in the present invention, the large diameter part of a two-stage coil spring is press-fitted into the end of the shaft cylinder to form a threaded groove, and the small diameter part of this spring presses an interior member such as a ballpoint pen refill. Since the tip and tail plug with spiral grooves are screwed into the large diameter part and fixed, the tip and tail plug can be removably screwed on without forming a screw on the barrel. The structure is simple and the number of manufacturing steps can be reduced. Since the spring is fixed to the barrel, there is no risk of the spring falling off and being lost during disassembly.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of the first embodiment, and FIG. 2 shows a sectional view of the second embodiment. 1... barrel, 2... ballpoint pen reflex, 3
...Tip end, 4...Two-stage diameter coil spring 4a...Large diameter part, 4b...Small diameter part, 6...Tail plug.

Claims (1)

[Scope of utility model registration request] The large diameter part of a two-step diameter coil spring, the outer diameter of which is slightly larger than the inner diameter of the barrel made of a cylindrical pipe, is press-fitted into the end of the barrel to form a threaded groove, and the small diameter part of this spring is used as a ballpoint pen reflex. The tip and tail plug of a writing instrument is characterized in that the tip and tail plug with a spiral groove are freely attached and detached to the large diameter part of the spring while pressing and biasing the inner parts such as the eel. Fixed structure.