JPS641104Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement in the assembly structure of the barrel, shaft coupling, and cap in a sharp pencil, and it improves the accuracy of the arrangement of the shaft coupling to constantize the lead-out and the cap. The purpose is to prevent the shaft joint from slipping during screwing.

For conventional metal barrels, for example,
55-41586, the length of the polygonal inner surface of the shaft cylinder that prevents rotation of the shaft joint is increased, and only when the shaft joint is fitted accurately can the threaded part of the shaft joint be a sufficient distance from the shaft cylinder. There was one that had a protruding cap that could be screwed on. However, if the shaft tube is made of a relatively thin metal such as stainless steel, it is difficult to form a polygonal surface only on the inner surface of the shaft tube, and if it is inserted as is, there will be a rotation stop when screwing the cap. Because of this, there was a risk that the shaft joint would spin idly.

The present invention is intended to solve this problem.

In the illustrated embodiment, a flange 3 is formed at the rear end to be able to abut against the edge of the tip opening 2 provided at the tip of the shaft tube 1, and a male threaded portion 4 is formed on the outer peripheral surface of the front end. A shaft coupling 6 is provided with an axial protrusion 5 whose dimension from the shaft center to the apex is larger than the radius of the shaft cylinder tip opening 2 on the outer circumferential surface only between the threaded portion 4 and the flange 3. Fitted onto the outer periphery of the split chuck 7, the joint 6
The protrusion 5 passes through a groove 8 provided on the edge of the tip opening 2 of the barrel 1, so that the tip protrudes to the outside of the barrel, and the male threaded portion 4 at the front end is attached to the base 9.
Here, the dimension from the tip of the protrusion 5 of the shaft coupling 6 to the tip of the male threaded part 4 of the shaft coupling is the distance from the rear end of the female threaded part 10 of the cap 9 to the rear end of the cap. The dimension is smaller than the sum of the thickness of the distal end surface 11 of the shaft cylinder 1.

That is, when the shaft coupling 6 is dropped into the shaft cylinder 1 from the rear, if the position of the protrusion 5 of the shaft joint 6 does not match the position of the groove 8 of the tip opening 2 of the shaft cylinder 1, a protrusion occurs as shown in FIG. The tip of the strip 5 abuts against the edge of the tip opening 2 of the shaft cylinder, and in this case, the male threaded portion 4 of the shaft coupling 6
does not reach the female threaded portion 10 of the cap 9, making it impossible to screw the cap 9. Therefore, the cap 9 can be screwed only when the position of the protrusion 5 on the shaft coupling 6 matches the position of the groove 8 on the shaft cylinder tip 2, and the protrusion 5 passes through the groove 8 and is accurately positioned. becomes. At this time, since the protrusion 5 of the shaft coupling 6 is fitted into the groove 8 of the shaft cylinder 1, the shaft coupling 6
This will also prevent him from idling.

As mentioned above, the present invention is a sharp pencil in which the tip of the shaft joint protrudes from the tip opening of the shaft cylinder, and the cap is screwed onto the threaded part formed on the outer circumferential surface of the projection. An axial protrusion whose dimension from the axis center to the apex is larger than the radius of the tip opening of the barrel is provided on the rear outer circumferential surface of the thread forming part, and a groove is provided on the edge of the tip of the barrel through which the protrusion can pass. The dimension from the tip of the protrusion of the shaft coupling to the tip of the threaded part of the shaft coupling is smaller than the distance from the rear end of the threaded part of the cap to the rear end of the cap plus the wall thickness of the tip surface of the shaft cylinder. As a result of this feature, the shaft joint is accurately assembled, the amount of lead-out of the core is made constant, and idling of the shaft joint is prevented, thereby achieving the above object.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention. Figure 1 is a vertical sectional view of the main part, Figure 2 is a sectional view taken along the line A-A in Figure 1, and Figure 3 shows a case where the shaft coupling is installed in an incorrect position. FIG. 1... shaft tube, 2... tip opening, 3... flange, 4...
...Male thread part, 5...Protrusion, 6...Shaft coupling, 7...
30% chuck, 8... groove, 9... cap, 10...
Female thread part, 11...Tip surface.

Claims (1)

[Scope of utility model registration request] In a sharpening pencil in which the tip of the shaft joint projects from the tip opening of the shaft cylinder and the base is screwed onto a threaded portion formed on the outer peripheral surface of the projection, the rear outer peripheral surface of the threaded portion of the shaft joint. An axial protrusion whose dimension from the center of the axis to its apex is larger than the radius of the tip of the shaft cylinder is provided on the top, and a groove through which the protrusion can pass is provided on the edge of the tip of the cylinder, and the protrusion of the shaft coupling. Sharp, characterized in that the dimension from the tip of the shaft coupling to the tip of the threaded part of the shaft joint is smaller than the distance from the rear end of the threaded part of the base to the rear end of the base plus the wall thickness of the front end surface of the shaft cylinder. pencil.