JPH034553Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to the barrel of a writing instrument such as a marker, and particularly to the improvement of the threaded structure of the barrel in which the tip shaft is screwed onto the barrel body. .

(Prior Art) In the barrel of a conventional writing instrument, which is constructed by screwing a tip barrel onto the barrel body, the male and female threads of the barrel body and tip barrel are both full-circumference threads. It has a mountain structure.

(Problem that the invention aims to solve) If both the male and female threads have a threaded structure all around the circumference, even if tightened with a large torque, the threads will plastically deform over time, so even if a small torque is applied, the threads will become loose. A phenomenon that occurs occurs. This tendency is particularly noticeable when either the male thread or the female thread is made of a flexible material. By the way, in the case of writing instruments, ink, etc. is stored inside the barrel, and if the threaded connection between the tip barrel and the barrel body loosens, the ink inside may evaporate or leak from the same location. Therefore, completeness is required to prevent loosening in the same place.

An object of the present invention is to provide a barrel for a writing instrument that completely prevents loosening of the threaded connection between the tip barrel and the barrel main body without using adhesives or the like.

(Means for solving the problem) In order to achieve the above-mentioned object, the present invention provides an internal screw thread in the barrel 4 of the writing instrument 3, which is constructed by screwing the tip barrel 2 onto the barrel body 1. It is characterized by providing a thread notch 7 in which the thread of the female thread does not come into contact with the thread of the female thread at a required location of the thread of the male thread that is screwed into the thread 5 while causing a slight deformation. It is something.

(Function) According to the above-mentioned structure, when the tip shaft 2 is screwed onto the barrel body 1, the female screw thread 5 screws into the male screw thread 6, causing a portion to be slightly deformed. 8
9, which is located in the thread notch and does not cause deformation.
The part 9 that does not undergo deformation is slightly recessed into the thread notch 7 and becomes locked, so that when the screw is released, deformation occurs in the thread 5 of the female thread. It is necessary to apply a force to reversely deform the part 9 where there is no part 9, and therefore, what used to be loosened when a force greater than the frictional force is applied sinks into the threaded notch 7 in addition to the frictional force and becomes locked. Unless a force is applied to deform the undeformed portion 9 and release the lock, it is impossible to loosen the portion 9.

(Embodiment) The figures show an embodiment of the present invention, and FIG. 1 is a front view of the male thread forming portion of the small diameter portion at the tip of the barrel main body 1;
Also, Fig. 2 is a side view seen from the tip side, and the barrel body 1 is made of a material that is harder and has a higher elastic modulus than the tip barrel 2, which will be described later, and has an axial screw thread notch located on its side surface. 7 is formed. Next, FIG. 3 is a longitudinal cross-sectional view of the tip shaft 2 screwed into the small diameter portion of the tip of the barrel main body 1. Mountain 5 is formed. FIG. 4 is a diagram of the screw thread 6 of the male screw and the screw thread 5 of the female screw, and FIG. 5 is a sectional view taken along the line A-A in FIG. A portion 8 that is slightly deformed occurs in the tooth surface meshing area between the thread 5 and the thread 6 of the male thread, and the thread 6 of the male thread
A state is shown in which a portion 9 of the female screw thread 5 located in the thread notch portion 7 has a portion 9 that does not undergo deformation. FIG. 6 is a longitudinal sectional view showing an example of the writing instrument 3 in which the main barrel body 4 is used.
The interior of the barrel is an ink container 10, and a valve mechanism 11 for controlling the amount of ink flowing from the ink container 10 into the tip barrel is installed inside the joint between the barrel body 1 and the tip barrel 2. There is a strong demand for preventing loosening of the threaded portion 12 between the shaft 2 and the shaft cylinder body 1.

(Effect of the invention) Since the present invention has the above-mentioned configuration, when the tip shaft and the barrel main body are screwed together, the undeformed thread of the female thread is slightly recessed into the thread notch of the male thread. Therefore, when trying to release the threaded state between the tip shaft and the barrel body, in addition to the conventional friction force, the female thread that is recessed into the thread notch of the male screw A force is required to reversely deform the undeformed threaded portion of the screw and release the engagement, thereby effectively preventing the threaded portion from loosening.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Figure 1 is a front view of the male thread forming part in the barrel body, Figure 2 is a side view as seen from the tip side of Figure 1, and Figure 3 is Fig. 4 is a vertical cross-sectional view of the female thread forming part of the tip shaft;
The figure is a sectional view taken along the line A-A in FIG. 4, and FIG. 6 is a longitudinal sectional view showing an example of a writing instrument using the main barrel. 1... barrel main body, 2... tip barrel, 3... writing instrument,
4... Shaft tube, 5... Female thread thread, 6... Male thread thread, 7... Thread notch, 8... Location subject to deformation, 9... Location not causing deformation, 10 …
... Ink container, 11 ... Valve mechanism, 12 ... Threaded part.

Claims (1)

[Scope of utility model registration request] In the barrel of a writing instrument, which consists of a tip shaft screwed onto the barrel body, female threads are inserted at the required locations of the threads of the male thread to which the threads of the female thread are screwed, while causing slight deformation to the threads of the female thread. 1. A barrel for a writing instrument, characterized by having a screw thread notch in which the screw threads of the writing instrument are in a non-contact state.