JPS5841199B2 - Automatic lead-feeding writing instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a writing instrument whose lead is automatically drawn out during writing.

Conventional mechanical pencils generally have a knock operation part protruding from the rear end of the main body, so that the lead can be drawn out in a knock-like manner by operating the finger, but each time you want to draw out the lead while writing, it is necessary to There was the inconvenience of having to carry it around.

In addition, recently, as the lead wears out during writing, when the lead guide pipe retreats due to being pushed by the writing surface, the pipe is pushed back to its original position with the lead when the writing pressure is released or when it retreats a certain amount. A type of writing instrument that automatically feeds out the lead has been developed, but conventional writing instruments of this type have drawbacks such as unreliable feeding operation and complicated structure. The tip of the pipe is fed out flush with the tip of the pipe, and the guide pipe comes into contact with the writing surface with a force that tries to restore it to the writing center, which causes problems such as impeding smooth writing.

In view of these circumstances, the present invention allows the lead to be fed out without the need for a knocking operation even if the lead wears out during writing, has a simple structure, provides a reliable feeding operation, and is capable of removing the lead. To provide an automatic lead-feeding writing instrument suitable for smooth writing by allowing the lead to protrude from the guide pipe in an appropriate manner without breaking.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

Reference numeral 1 denotes a writing instrument body, which is formed into a substantially cylindrical shape with a required length by connecting a front body 1a and a rear body 1b via an intermediate ring IC, and has a head 2 having a conical outer shape at the tip. It becomes by screwing it on.

The head 2 also functions as a feeding amount adjustment dial, and a rubber backing 3 is provided between the head 2 and the front main body 1a.
is interposed.

Reference numeral 4 designates a lead guide pipe that is provided at the front of the main body 1 and is slidable within a certain range in the axial direction, and 5 represents a lead storage cylinder for storing spare leads.

In the illustrated example, the core storage tube 5 is slidably installed at the rear of the main body 1, and the rear part of the pipe 4 is inserted into the front small diameter part of the core storage tube 5, and the cross section of the tip of the core storage tube 5 is shown. U-shaped frame 6
By locating the rear collar portion 7 of the pipe 4 inside, the pipe is connected to the core storage cylinder 5 so as to be movable within a certain range in the axial direction.

The tip of the core guide pipe 4 passes through an insertion hole 8 formed in the head of the main body 1 and projects forward from the tip of the head 2.

In addition, the core storage cylinder 5
It is prevented from coming off by a stopper 9 for preventing it from coming off, which is provided so as to protrude toward the back of the tip frame portion 6.

Numerals 10 and 15 are core chucks attached to the outer periphery of the core guide pipe 4 at predetermined rear and front positions.

The first core chuck 10 located at the rear has an appropriate number of balls 11 with a portion facing inside the pipe 4.
and a ball holding frame 12.

The holding frame 12 is externally fitted onto the pipe 4, and has a tapered ball receiving surface 12a at the rear end of its inner periphery for applying a chucking force to the .phi.

The balls 11 are inserted into the small through holes 13 provided in the pipe 4, and the balls 11 are inserted into the ball holding frame 1.
The first chuck 10 is housed so as to be able to move back and forth to a certain extent with respect to the core guide pipe 2, and the holding frame 12 is allowed to move relative to the core guide pipe 4 only within this movable range. 4.

Further, between the holding frame 12 and the tip frame portion 6 of the core storage cylinder 5, there is a coil spring 1 that elastically presses the holding frame 12 forward.
4 is interposed.

On the other hand, the second core chuck 15 located at the front, like the first chuck 10, has an appropriate number of balls 16 and a ball holding frame 17 having a tapered ball receiving surface 17a at the rear end of the inner periphery. The ball 16...
... is a long through hole 18 provided in the core guide pipe 4.
By facing the inside of the pipe 4 through the long through hole 18, it is configured to be movable relative to the pipe 4 within the range of the elongated hole 18.

Further, a second chuck 10 is provided between the holding frame 17 and a flange 20 protruding from a predetermined location in the middle of the core guide pipe 4.
A coil spring 19 is interposed to elastically press forward.

Reference numeral 21 denotes an elastic locking piece formed of a leaf spring, one end of which is fixed to the writing instrument main body 1, and an inwardly inclined portion 22 facing the movement path of the first chuck 10 is formed at a predetermined location in the middle. When the first chuck 10 moves forward by the elastic force of the spring 14, it is pushed outward and opened, and when the first chuck 10 retreats, it closes inward by its own restoring force.

A locking portion 23 bent inwardly is provided at the free end of the locking piece 21 and is removable from the rear end protrusion 17' of the ball holding frame 17 of the second chuck 15.

Further, a stopper 24 corresponding to the flange 20 of the core guide pipe 4 when the pipe is retracted is formed at a predetermined location of the locking piece 21.

Although at least one elastic locking piece 21 may be provided, it is preferable to provide a plurality of elastic locking pieces 21 at regular intervals in the circumferential direction as shown in the figure in order to ensure their operation.

In the feeding mechanism composed of both chucks 10, 15, springs 14, 19, and elastic locking piece 21, the first chuck 10 receives the pen pressure and moves backward S, and the second chuck 15 functions to pull out the lead. Therefore, the elastic locking piece 21 releases the second chuck with a certain delay with respect to the first chuck 10 when the pen pressure is released.
It operates the chuck 15, and the springs 14, 19
The elastic force of is related to these functions.

In order to ensure the feeding operation by these, the elastic force of the spring 19 of the second chuck 15 is equal to that of the spring 1 of the first chuck 10.
4, and in order to equalize the gripping force of both chucks 10 and 15 in relation to the springs 14 and 19, the first chuck 1
It is desirable that the taper of the ball receiving surface 12a in the second chuck 15 be relatively steep, and that the taper of the ball receiving surface 17a in the second chuck 15 be relatively gentle.

Further, 25 is a coil spring provided between the stopper 9 protruding from the inner circumferential surface of the main body 1 and the lead storage cylinder 5, and 26 is a cap for knock operation fitted over the rear end of the lead storage cylinder. The operating mechanism is mainly used when guiding the lead from the lead storage cylinder 5 to the lead guide pipe 4.

The spring 25 is the spring 14, 19 of each chuck 10.15.
Make it stronger.

27 is an eraser fitted to the rear end of the lead storage cylinder 5.

The operation and function of the writing instrument with the above configuration will be explained next.

Assuming that the lead 30 has been inserted into the lead guide pipe 4 in advance, when the writing pressure is not greater than a predetermined value, the state is as shown in FIG. 1.

If a certain amount of writing pressure is applied to the tip of the lead 30 during writing in this state, the lead 30 is gripped by both chucks 10 and 15, and the lead 30 and the lead guide pipe are held against the elasticity of the spring 140. 4 and both chucks 10°15 move back.

Accordingly, the ball holding frame 12 of the first chuck 10 is released from the inclined part 22 of the elastic locking piece 21, the locking piece 21 closes inward, and the locking part 23 at the tip of the elastic locking piece 21 is moved away from the second chuck 15.
(the third
(see figure a).

When the flange 20 of the pipe 4 retreats to the position where it abuts the stopper 24, the core 30 is held by the first chuck 10 and therefore does not retreat any further.

Next, when the pen pressure is released, the first chuck 10 moves forward due to the elastic force of the spring 14.

At this time, the first chuck 10 is attached to the inclined portion 2 of the elastic locking piece 21.
2, as shown in Figure 3, until just before contacting the 2nd
The chuck 15 is locked by the locking portion 23 of the elastic locking piece 21, and both chucks 10.15 exert a strong gripping force in the direction in which the lead 30 retreats relative to each other, and the chuck 10.15 is held in the opposite direction. Since the gripping force is weak, the lead 30 and the lead guide 5 < Eve 4 move forward together with the Σ first chuck 10 while the second chuck 15 is stopped.

When the first chuck 10 moves further forward, the elastic locking piece 21 is pushed outward and the locking part 23 is released from the second chuck 15, as shown in FIG. 3C. The chuck 15 advances to its original position with a certain delay compared to the first chuck 10, and delivers the core 30 by a certain amount to the pipe 4.

In this case, by using the stepped inner surface of the main body head 2 as a stopper for the second chuck 15 and adjusting the rotation of the head 2, the amount of feeding out of the core 30 can be adjusted at will.

In this way, even if the lead 30 is worn out by writing, the lead 30 will be automatically fed out by repeatedly pressurizing and releasing the pressure applied to the tip of the lead 30 during writing.

In addition, in this feeding mechanism, the strength and amount of feeding of the spring 140 are set so that the lead 30 is fed out in small amounts at a time commensurate with the consumption of the lead based on the normal writing pressure during writing work. The spring 14 is designed so that the feeding operation is performed when pressure is applied to a certain degree stronger than normal writing pressure.
You may also set the strength of

According to the latter, it is easy for the user to adjust the feeding amount.

In addition, when the lead 30 is led out from the lead storage cylinder 5 to the lead guide pipe 4 in use, by knocking the rear end cap 26 as shown in FIG. to advance further than its normal forward position.

By doing this, the ball holding frames 12 and 17 of each chuck 10 and 15 can be attached to the stopper 2 provided on the elastic locking piece 21.
4 and the inner surface step part of the head 2, etc., the spring 14,
Ball 11 without being affected by 190...
16... is the ball receiving surface 12a.

It is released from 17a and the chuck action is completely released,
As a result, the core 30 can be guided into the core guide pipe 4 by its own weight.

Further, it is also possible to withdraw the lead 30 that has been drawn out too much by this operation, or to insert the lead 30 into the lead guide pipe 4 from the tip.

In addition, in the writing instrument of the present invention as described above, as a means for springing the first and second chucks forward, instead of the coil springs 14 and 19, a pair of magnets that repel each other are arranged front and back, respectively. It is also possible to equip the ball holding frame of each chuck and the corresponding location in this state, and use the repulsive force of this magnet to achieve the same effect as the coil springs 14 and 19.

In addition, the specific structure of each part of the writing instrument of this invention is as follows:
It goes without saying that any design changes may be made without departing from the gist of the present invention.

As described above, the writing instrument of the present invention includes a first lead chuck that is movable together with the lead guide pipe, a second lead chuck that is movable relative to the pipe, and a second lead chuck that is responsive to the first lead chuck. With an elastic locking piece that engages and disengages the second chuck, when the lead and lead guide pipe and both chucks move back a certain amount as pressure is applied and released during writing, the first chuck and the lead and the lead are moved back by a certain amount. The guide pipe returns to its original position, and after a certain delay, the second chuck advances to its original position and feeds out the lead, so even if the lead wears out during writing, you can still hold the main body and perform knocking operations. The lead can be automatically fed out according to the pressure of the pen without having to do so.

In particular, unlike conventional automatic feeding mechanisms, where the lead is not flush with the lead guide pipe, the lead is fed out with a moderate amount of protrusion from the lead guide pipe to prevent the lead from breaking, resulting in a pleasant writing experience. In addition, it has many excellent advantages, such as being able to reliably feed and hold the lead with both chucks without using an uncertain mechanism such as using frictional resistance between the lead and the lead guide pipe. It is effective.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of the entire writing instrument, Fig. 2 is an enlarged perspective view of the elastic locking piece, and Figs. Part half sectional view, 4th
The figure is a half-sectional view of the main part when the knock mechanism is operated. 1... Writing instrument body, 4... Lead guide pipe, 10... First chuck, 11...
・Ball, 12...Ball holding frame, 15...
...Second chuck, 16...Ball, 17.
... Ball holding frame, 21 ... Elastic locking piece.

Claims (1)

[Claims] 1. A lead guide pipe that can slide within a certain range in the axial direction is equipped on the front part of the writing instrument body, and a ball that partially faces inside the lead guide pipe is placed on the rear surface of the inner periphery on the outer periphery of three places on the front and back of the pipe. A core chuck held in a tapered ball receiving frame is attached, and the first chuck is movable with the core guide pipe and springs forward by a spring or magnet, and the second chuck is moved against the core guide pipe. It is movable in the axial direction by a fixed amount relative to the chuck, and is projected forward by a knife or a magnet, and is swingable in accordance with the movement of the first chuck, and the tip can be engaged with and detached from the second chuck. An elastic locking piece with a locking part is provided, and when a pressurizing force is applied to the tip of the core with the core inserted into the core guide pipe, the core, the core guide pipe, and both chucks retract by a certain amount. Accordingly, the second chuck is locked by the locking piece, and when the pressing force is released, the first chuck, the core, and the core guide pipe move forward to their original positions, and
An automatic lead feeding type writing instrument characterized in that the locking piece is separated from the second chuck with a certain delay and the chuck moves forward to feed out the lead to the lead guide pipe.