JPS6226237Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a ballpoint pen and other retractable writing instruments.

When rotating the cap to move the lead of a ballpoint pen, pencil lead, etc. forward and backward from the barrel, if you increase the lead of the screw that guides the lead movement, you can easily move it in and out with less rotation. The tip sometimes sank into the barrel due to pressure, etc.
Various configurations have been proposed to improve these drawbacks, but few are satisfactory.

The present invention has improved such drawbacks and has various other features.The present invention has a rotating cylinder that holds the core and an inner cylinder that rotates the rotating cylinder that slide with an engaging groove and an engaging protrusion. A drawing type writing instrument characterized in that a locking step is provided in a part of the engagement groove so that the engagement protrusion engages when the lead is in a writing position, When the lead tries to retract in the longitudinal direction, the locking step and the engagement protrusion engage, preventing the lead from moving in the axial direction, causing the lead to retract due to the pressure of the writing. You can avoid it.

This will be explained below along with examples.

In the case shown in the figure, lead 1 of a ballpoint pen, etc.
The rear end is fitted into a mounting piece 2, and the mounting piece 2 is screwed 4 to a rotary cylinder 3. The rotary cylinder has a male thread 5 at its lower end, which is threaded into a female thread 8 of a guide cylinder 7 connected to the shaft cylinder 6. The guide tube has an outer tube 9 fixed to its outer periphery by caulking or the like,
Although the shaft cylinder is press-fitted and fixed to the outer cylinder, it is also possible to omit the outer cylinder and make the guide cylinder and the shaft cylinder integrally.

There is an inner cylinder 11 which is rotated by the cap 10 and which is fitted around the rotating cylinder. An engagement groove and an engagement protrusion that engages with the groove are provided between the inner cylinder and the rotary cylinder to rotate the rotary cylinder. In the one shown in the figure, a large-diameter portion 12 is provided on the outer periphery of the rotating cylinder, an engagement groove 13 extending in the longitudinal direction is formed in the large-diameter portion, and the large-diameter portion is fitted into the tip of the inner cylinder. A holding part 14 is provided, and a part of the holding part is recessed to provide an engaging protrusion 15, but the engaging groove and the engaging protrusion are provided on a member opposite to that shown in the figure. Can be done. A locking step 16 is provided in a part of the engaging groove so that the engaging protrusion 15 is engaged with the lead when the lead is in the writing position (FIG. 2). The engagement protrusion and the locking step engage when pushed in the axial direction, so even if a force that presses the rotary tube in the longitudinal direction is applied at the writing position, the rotary tube will not move in the longitudinal direction. Therefore, there is no fear that the lead will sink into the barrel due to pen pressure.

A brake pipe 17 is fitted around the inner cylinder. As shown in FIG. 4, the brake pipe is made in a cylindrical shape and preferably has an annular protrusion 18 projecting outward;
It has an annular groove 19 that protrudes inward, and when fitted into the inner cylinder, the protrusion and groove are pressed between the outer surface of the inner cylinder 11 and the inner surface of the outer cylinder 9, and the inner cylinder Since free rotation of the cylinder is prevented, even if the lead is pushed back by the pressure of the writing, the rotation of the rotary cylinder engaged with the inner cylinder can be stopped, and therefore the return caused by the pressure of the writing is further reduced. Note that both ends of the brake pipe are in contact with the stepped portion 21 of the inner cylinder and the flange 22 of the outer cylinder via guide rings 20, respectively. The annular protrusion, annular groove, etc. provided on the brake pipe can have a structure having a protrusion projecting inwardly or outwardly, a discontinuous groove, or other appropriate frictional braking function. The groove may be replaced by three or more or fewer inwardly protruding protrusions 23 as shown in FIG. In addition, rotational braking can also be achieved by crimping the brake pipe in the axial direction between the stepped portion of the inner cylinder and the flange of the outer cylinder.

When the cap is rotated while holding the shaft cylinder, the tip of the core protrudes from the tip 24, and at this time, the rotary cylinder that holds the core is inserted into the locking step of the engagement groove of the inner cylinder. Since the engaging protrusions engage, even if a force is applied in the direction of pushing the pen into the barrel due to pen pressure, its movement is prevented and the tip will not be recessed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is an enlarged sectional view, Fig. 2 is a front view of the rotating cylinder, Fig. 3 is a perspective view of the inner cylinder, Fig. 4 is a perspective view of the brake pipe, and Fig. 5 is a perspective view of the brake pipe. The figure is a sectional view of the brake pipe.

Claims (1)

[Scope of utility model registration request] A rotary cylinder that holds the core is screwed into a guide tube connected to the shaft cylinder, and the rotary cylinder is rotated by an inner cylinder connected to the cap, and the rotary cylinder is moved back and forth to cause the core to emerge and retract from the tip of the shaft cylinder. The rotating cylinder and the inner cylinder are slidably engaged by an engaging groove provided on one side and an engaging protrusion provided on the other side, and when the core protrudes from the tip of the shaft cylinder, the engaging protrusion A feeding-type writing instrument, in which a locking step is provided in a part of the engagement groove for engagement.