JPH0139592Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention uses a ball chuck as a core clamping mechanism, and the operation knob that is exposed on the side of the barrel is pushed forward with a finger and then released (guide knob).
The present invention relates to an expanding device for a ball chuck for a mechanical pencil, which feeds out the lead.

In a ball chuck, a chuck spring is stretched between a chuck body that forms the seat of the trochanter and a chuck actuating body whose seating surface for the trochanter is an inclined surface. Because it has a unique structure compared to the three-split chuck, which is a known lead-clamping mechanism, it is used for continuous writing type sharp pencils (with a lead detent attached and biased backwards by a spring). However, the slider protrudes from the tip of the barrel so that the lead is flush with the tip of the slider so that you can write continuously without knocking) and/or the sharpening pencil with a notch tip. It is used. In this ball chuck, as with the three-split chuck, it is necessary to feed out the lead and perform second centering (when the lead wears out, the lead in the lead storage chamber is made to protrude from the tip of the barrel), so the lead is held at a predetermined length. After extrusion, the chuck must be kept open so that it does not move back and pull the core back. For this purpose, the mutual positional relationship between the chuck body and the chuck operating body when reversing is such that the chuck operating body is located behind the chuck body when the chuck is closed, and such a mutual positional relationship is maintained. However, ensuring that this was achieved required considerable skill in practice.

On the other hand, known side-knock type sharp pencils use a three-split chuck, and are superior to rear-end grip type sharp pencils in that they can make a notch without changing the gripping position. Since the punch is usually made with the index finger, it is desirable to be able to punch with light pressure.

Therefore, the present invention is a ball chuck that allows reliable feeding of the lead and/or second centering,
The object of the present invention is to provide an expanding device that allows a ball chuck to be expanded with a slight side knock, and will be described below with reference to an embodiment shown in the drawings.

The chuck actuating body 2 of the ball chuck fitted into the shaft cylinder 1 is biased backward by the internal spring 6, and the protrusion 3 formed on the outer surface of the chuck actuating body 2 is pushed into the stepped part 1 of the shaft cylinder.
By pressing against b, the chuck operating body 2 occupies a steady stationary position, and can advance from this steady stationary position until the front end face 4 of the chuck operating body 2 collides with the opposing shaft cylinder step portion 1a. In this invention, a slit is provided in the rear cylindrical portion of the chuck actuating body 2, and an inclined stepped portion 16 of the pressing member 12, which will be described later, is provided on the inner surface of the cylindrical portion.
A resistance point 5 is formed which engages with. The resistance point 5 can be formed by an O-ring separate from the chuck actuating body as shown in FIG. 4 (in this case,
It is not necessary to provide a slit in the cylindrical portion), but instead of providing the slit on the inner surface of the rear cylindrical portion of the chuck actuating body 2 as shown in FIG. 5, the slit may be provided at the rear end. Further, as shown in FIG. 6, the chuck actuating body 2 is provided with an inclined stepped portion 26,
A resistance point 25 may be provided on the pressing member 12 (in this case, a friction receiving surface 22a, which will be described later, will be on the rear inner surface of the chuck operating body 2).

The chuck body 7 of the ball chuck has a chuck spring 8 and a trochanter 9 stretched between it and the chuck operating body 2.
The device applies a tightening force to the chuck part in its steady state, and eliminates the tightening force of the chuck part by moving forward to change the mutual positional relationship with the chuck actuating body 2. In addition to making it easier to open by adding some cracks to the part, an appropriate self-expanding force is given in advance. Preferably, as a means for forcibly expanding the chuck part, a protruding engaging part 10 is formed on the front end surface of the chuck body 7, and the other protruding engaging part 11 that cooperates with the protruding engaging part 10 is attached to the shaft cylinder 1. By forming the chuck on itself and making the protruding engaging part 10 rise above the protruding engaging part 11, the chuck part is forcibly expanded. This will be more effective when centering the second line.

At the rear of the chuck body 7, there is an operation knob 1 which is biased backward by a push spring 14 and which is exposed on the side surface of the shaft cylinder 1.
3, a pressing member 12 that can be moved back and forth is provided.
The pressing member 12 is formed with a friction receiving surface 12a and an inclined stepped portion 16 which engages with the resistance point 5 of the chuck actuating body 2, which is continuous with the friction receiving surface 12a.

Next, talking about the operation, when the operation knob 13 is pressed as shown by the arrow in FIG. 2, the pressing member 1
Since the resistance point 5 is pressed by the inclined step portion 16 of the chuck actuating body 2 (as well as the chuck body 7)
The front end surface 4 of the chuck actuating body 2 is pressed against the stepped portion 1a of the shaft cylinder, and the forward movement is blocked. Furthermore,
When the operating knob 13 is pressed as shown by the arrow in FIG.
moves forward, the front end surface 18 of the pressing member 12 pushes the rear end surface 17 of the chuck body 7, and the mutual positional relationship changes to such that the chuck body 7 is advanced further than the chuck actuating body 2 (the chuck body 7 is in an open state). . On this occasion,
In the chuck actuating body 2, the resistance point 5 is connected to the pressing member 12.
maintains a state of frictional engagement with the friction receiving surface 12a. When the pressure on the operating knob 13 is released from the state shown in FIG. The pressing members 12 maintain the mutual positional relationship shown in FIG. 3 and retreat. When the protrusion 3 of the chuck operating body 2 collides with the stepped portion 1b of the shaft cylinder, the backward movement of the chuck operating body 2 is prevented.
The elastic force of the push spring 14 releases the friction lock between the resistance point 5 and the friction receiving surface 12a, the push member 12 retreats, and finally the chuck body 7 is released as shown in FIG. The chuck is moved back and closed by the elastic force of the chuck spring 8.

In the figure, 15 indicates a guide hole of the operating knob 13, and 19 indicates a core detent, but it does not matter whether it is attached to the shaft tube 1 or the slider 20.

As is clear from the above explanation, this idea is
Use of ball chuck, resistance points 5, 2
5 through the inclined step portions 16, 26 and the friction receiving surface 12a,
22a, the spring force of the internal spring 6 and the pressing spring 14 can be reduced to 20 g, for example.
As a result, the pressing force on the operating knob 13 can be made light, and after the pressing force on the operating knob 13 is released, the resistance points 5 and 25 are subjected to friction. Surface 12a, 2
Since the ball chuck is frictionally engaged with 2a and the entire ball chuck is retracted while the chuck body 7 is reliably expanded, it is possible to reliably feed out the lead and center the second one.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the present invention, FIGS. 2 and 3 are explanatory views of the operation, and FIGS. 4 to 6 are sectional views of main parts showing other embodiments. 1... Shaft cylinder, 2... Chuck operating body, 5, 25
... Resistance point, 6 ... Internal spring, 7 ... Chack body, 8 ... Spring for chuck, 9 ... Trochanter, 12 ...
...Press member, 12a, 22a...Friction receiving surface, 13
...Operation knob, 14...Press spring, 16, 26...
...Sloped step.

Claims (1)

[Scope of utility model registration request] The chuck operating body 2 is biased backward by an internal spring 6 provided in the barrel 1, and the pressing member 12 is connected to the operation knob 13 exposed on the side surface of the barrel 1 and biased backward by a pressure spring 14. Resistance points 5, 25 on either side
The other side is provided with friction receiving surfaces 12a, 22a and inclined step portions 16, 26, and a chuck stretched between the chuck actuating body 2 and the chuck actuating body 2 is provided inside the chuck actuating body 2 and in front of the pressing member 12. spring 8 and trochanter 9
The chuck body 7 of the ball chuck attached through the
By pressing the operating knob 13, the inclined steps 16, 26 and the resistance points 5, 25 are engaged to move the entire ball chuck forward by a certain distance, and by further pressing the operating knob 13, the chuck body 7 is moved forward and expanded. Open the resistance points 5, 25 to the friction receiving surfaces 12a, 22.
This expanding device for a ball chuck for a sharp pencil is configured to be frictionally engaged with the ball chuck (a) and to retract the entire ball chuck while maintaining the expanded state of the chuck body 7 by releasing the pressure on the operation knob 13.