JP5106189B2 - Intrusion mechanical pencil - Google Patents

Description

  The present invention relates to a retractable mechanical pencil that projects a tip member from a tip end of a shaft cylinder by pressing a knob protruding from the rear end of the shaft cylinder.

2. Description of the Related Art Conventionally, there is known a mechanical pencil with a built-in base that presses a knob protruding from the rear end of a shaft cylinder to lock a knock mechanical pencil body at a forward position and a backward position with a rotary cam and a pressing tool. (See Patent Document 1)
Japanese Utility Model Publication No. 52-37545

  However, by pressing a knob that protrudes from the rear end of a conventionally known shaft cylinder, the mechanical pencil with a built-in base that locks the knock-type mechanical pencil body at the forward position and the backward position with a rotating cam and a pusher, The structure of the lead tank was complicated, resulting in poor productivity and high cost. In addition, the spring S3 must be stronger than the pen pressure, but the pen pressure varies from person to person. To ensure operation, the spring S3 must have a very strong mounting load and must be knocked with a strong force. I had to. Further, when the spring S3 is strengthened, there is a possibility that members such as the rotating cam, the cam barrel, and the front shaft barrel and the rear shaft barrel are damaged. Further, since the spring S3 must not extend more than a certain distance even in a natural state, the dimensions of members such as the core case, the chuck, and the base vary, so that the spring S3 is pushed against the rotating cam 11 when the cap is pressed and when it is carried. If the chuck comes into contact with the slider built in the base before the tool 10 comes in contact, the rotary cam 11 cannot be rotated, and the rotary cam 11 cannot be locked in the forward position. there were.

  An object of the present invention is to provide a retractable mechanical pencil that solves the above problems.

The present invention relates to a knock type mechanical pencil body having an inner shaft provided with a tip member at the front portion, a core tank built in the inner shaft, a chuck connected to the front portion of the core tank, a chuck and a core tank A chuck spring that biases the inner shaft rearward, a rotating cam built in the shaft cylinder, a return spring that biases the inner shaft rearward in the longitudinal direction, a pressing member attached to the rear of the core tank, A retractable mechanical pencil that includes a knob provided on a member, causes the tip member to protrude from the tip of the shaft tube by pressing the knob, and locks the rotating cam to the locking portion of the shaft tube. the lead tank connected by press fit affixed to the rear and a synthetic resin pipe, assembling the knock-type mechanical pencil body by press-fitting fixing the pressing member to the rear of the lead tank, constituting the barrel between the front axle A plurality of forming a cam groove and a plurality of engaging portions extending in the longitudinal direction on the inner surface of the shaft after that, and to form a projection and the inclined portion in the rotating cam, further, the projection and the inclined portion pressing member The knock type mechanical pencil body is inserted from the rear of the front shaft, a return spring is stretched between the rear end of the front shaft and the outer shaft formed on the inner shaft, and the knock type is inserted into the cam groove of the rear shaft. The projecting portion of the push member of the mechanical pencil body is inserted so as to be slidable in the longitudinal direction, and the inclined portion of the pressing member and the inclined portion of the rotating cam are configured to be able to contact each other. It is configured so that it can be locked to the locking part, a coil spring is stretched between the inner shaft and the rotating cam with a mounting load that is weaker than the mounting load of the return spring, and the front shaft and the rear shaft are screwed together to form a shaft cylinder The gist of this is

  In the retractable mechanical pencil of the present invention, by constructing the core tank with a synthetic resin pipe, the structure is simple, the productivity is improved, and the effect of being produced at low cost is obtained.

Even in a state where the chuck is brought into contact with the locking step of the tip member to advance the inner shaft, the rotating cam is urged rearward by the coil spring, and the inclined portion of the rotating cam becomes the front protrusion of the pressing member. Since they are brought into contact with each other, it is possible to obtain an effect of reliably rotating the rotating cam and locking it to the locking portion of the rear shaft .

  A retractable mechanical pencil has been realized that can reliably rotate the rotating cam and lock it in the forward position even if the dimensions of the lead tank, chuck, or tip member vary.

  Hereinafter, a retractable mechanical pencil according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4. Moreover, let the left side of FIG. 1 be the front, and let the right side be back. First, a front part of a metal chuck 1 made of brass or the like is divided into three parts, and a core tank 2 formed of a synthetic resin pipe is press-fitted and fixed to the rear part of the chuck 1. A clamping ring 3 is fitted on the head 1 </ b> A of the chuck 1, and a chuck spring 5 is stretched between the connector 4 that receives the clamping ring 3 and the front end of the core tank 2 with a load of about 400 g. Therefore, the head 1 </ b> A of the chuck 1 that is normally urged rearward by the chuck spring 5 holds the core 6 by being pressed and closed by the fastening ring 3. The mechanism portion configured as described above is inserted from the front of the inner shaft 7, and the connector 4 is brought into contact with the front end of the inner shaft 7. Further, the front member 8 is detachably screwed to the front portion of the inner shaft 7, and the connector 4 is held between the inner step 8 </ b> A of the front member 8 and the front end of the inner shaft 7. A lead holder 9 that holds the lead 6 lightly is built in the tip member 8.

  A grip 11 made of a soft material such as rubber is put on the grip portion of the front shaft 10. Further, three cam grooves 12A extending in the longitudinal direction are formed on the inner surface of the rear shaft 12 at equal intervals in the circumferential direction. The front end of the cam groove 12A is provided with a vertical surface 12B in the middle portion and the vertical surface 12B. The inclined surfaces 12C in the same direction are formed on both sides of the.

  The rotating cam 13 has three protrusions 13B projecting outward and rearward from the cylindrical portion 13A at equal intervals in the circumferential direction, and has a rear end surface in the same direction as the inclined surface 12C of the rear shaft 12. An inclined portion 13C that is inclined is formed. The rotating cam 13 is fitted on the lead tank 2 so as to be rotatable and slidable in the longitudinal direction. A coil spring 14 is attached between the inner stage 7 </ b> A of the inner shaft 7 and the rotary cam 13.

Further, a pressing member 15 is press-fitted and fixed to the rear portion of the lead tank 2. The push member 15 has three protrusions 15A formed at equal intervals in the circumferential direction, and a front protrusion 15B configured by two inclined portions and protruding forward is formed at equal intervals in the circumferential direction at the front end. Six are formed. Further, an eraser 16 is provided at the rear portion of the pressing member 15 and a knob 17 covering the eraser 16 is fitted to form a knock-type mechanical pencil body U.

The knock-type mechanical pencil body U assembled as described above is inserted from the rear of the front shaft 10 and the return spring 18 is about 900 g between the rear end of the front shaft 10 and the outer rod 7B of the inner shaft 7. It is stretched with a load. Further, the protrusion 15 </ b> A of the pressing member 15 is inserted into the cam groove 12 </ b> A of the rear shaft 12, and the rear shaft 12 is screwed to the front shaft 10. The front shaft 10 and the rear shaft 12 constitute a shaft cylinder. 1 and 2, the protruding portion 13B of the rotating cam 13 is locked to the locking portion formed by the inclined surface 12C and the vertical surface 12B of the rear shaft 12, and the inner shaft 7 is attached to the front end of the rotating cam 13. The rear end is abutted. At this time, the coil spring 14 is compressed and stretched with a load of about 50 g.

  When writing is performed in this writing state and the lead 6 is worn, the knob 17 protruding from the rear end of the rear shaft 12 is pressed. Then, since the load of the return spring 18 is larger than the loads of the chuck spring 5 and the coil spring 14, the chuck 1 moves forward and the lead 6 is fed out.

  Next, in order to finish writing and immerse the tip member 8 into the front shaft 10, the knob 17 is pressed to expand the chuck 1, and the front protrusion 15 </ b> B of the pressing member 15 is the protrusion of the rotary cam 13. It contacts the inclined portion 13C formed on 13B. At this time, if the size of the member such as the tip member 8 or the core tank 2 varies, the chuck 1 comes into contact with the locking step 8B of the tip member 8 before the rotating cam 13 and the pressing member 15 come into contact. The return spring 18 is compressed and the inner shaft 7 moves forward together with the pressing member 15, and the inclined portion 13 </ b> C of the rotating cam 13 and the front protrusion 15 </ b> B of the pressing member 15 are separated from each other. Therefore, when the pressing member 15 moves forward, the inclined portion 13C of the rotating cam 13 and the front protrusion 15B of the pressing member 15 come into contact with each other. Then, the rotary cam 13 moves forward together with the pressing member 15, and the protrusion 13 </ b> B of the rotary cam 13 is disengaged from the vertical surface 12 </ b> B of the rear shaft 12 to rotate the rotary cam 13.

When the pressing of the knob 17 is released in this state, the knock type mechanical pencil body U is urged by the return spring 18 and the rotary cam 13 urged rearward by the coil spring 14 has the protrusion 13B at the rear. The cam groove 12A of the shaft 12 is slid rearward. Then, the rear end of the protrusion 15A of the pressing member 15 comes into contact with the rear end edge 12D of the cam groove 12A of the rear shaft 12, and the portable state shown in FIGS. At this time, since the chuck 1 is locked to the locking step 8B of the tip member 8, the front end of the rotating cam 13 and the rear end of the inner shaft 7 are separated from each other.

When returning to the writing state, the knock type mechanical pencil body U is advanced by pressing the knob 17 . When the protruding portion 13B of the rotating cam 13 is disengaged from the cam groove 12A of the rear shaft 12, the inclined portion 13C of the rotating cam 13 and the front protruding portion 15B of the pressing member 15 that are in contact with each other become inclined surfaces. Therefore, the rotating cam 13 rotates, and the protrusion 13B of the rotating cam 13 is locked to the locking portion formed by the inclined surface 12C and the vertical surface 12B of the rear shaft 12, and the state shown in FIG. When the pressing of the knob 17 is released in this state, the chuck 1 is retracted by the chuck spring 5, and the chuck 1 is pressed by the fastening ring 3 to be closed and returns to the writing state of FIG.

  In addition, this invention is not limited to the said Example 1, The members, such as a front axis | shaft, a rear axis | shaft, an inner axis | shaft, or a pushing member, can also integrate several members by adhering or fitting. . In the first embodiment, the case where the front end of the chuck is in contact with the locking step of the tip member has been described, but the inner shaft is moved forward, for example, the chuck spring is fully compressed to move the inner shaft forward. Various causes can be considered.

  Even if the member such as the tip member, the chuck or the lead tank is somewhat dispersed, the rotary cam can be reliably operated and locked to the locking portion of the shaft tube, and can be applied to a retractable mechanical pencil that can be produced at low cost.

It is sectional drawing which shows the writing state of the retractable mechanical pencil of Example 1 of this invention. Example 1 FIG. 2 is a development view showing a state in which a protruding portion of the rotating cam in FIG. Example 1 It is sectional drawing which shows the carrying state of the retractable mechanical pencil of Example 1 of this invention. Example 1 FIG. 4 is a development view showing a state in which a protruding portion of the rotating cam in FIG. Example 1

DESCRIPTION OF SYMBOLS 1 Chuck 2 core tank 5 Chuck spring 7 Inner shaft 8 Tip member 13 Rotating cam 13B Projecting part of rotating cam 13 13C Inclined part of rotating cam 13 14 Coil spring 15 Pushing member 15A Projecting part of pushing member 15 17 Knob 18 Return spring
U knock mechanical pencil

Claims (1)

The knock type mechanical pencil body has an inner shaft provided with a front member at the front portion, a core tank built in the inner shaft, a chuck connected to the front portion of the core tank, and the chuck and the core tank rearward in the longitudinal direction. A chuck spring that urges the inner shaft, a rotating cam built in the shaft cylinder, a return spring that urges the inner shaft rearward in the longitudinal direction, a pressing member attached to the rear portion of the core tank, and a pressing member. and consists of a knob, causes protrude from the tip end of the barrel the previous member by pressing the knob, a retractable mechanical pencil locking the rotation cam to the locking portion of the barrel, press-fitted into the rear portion of the chuck the lead tank connected by fixed and a synthetic resin pipe, assembling the knock-type mechanical pencil body by press-fitting fixing the pressing member to the rear of the lead tank, the rear axle constituting the barrel between the front axle Forming a plurality of cam grooves and a plurality of engaging portions extending in the longitudinal direction on the surface, and to form a projection and the inclined portion in the rotating cam, further, forming a projection and the inclined portion pressing member, knock A mechanical pencil body is inserted from the rear of the front shaft, a return spring is stretched between the rear end of the front shaft and the outer shaft formed on the inner shaft, and the knock type mechanical pencil body is inserted into the cam groove of the rear shaft. The protrusion of the push member is slidably inserted in the longitudinal direction so that the inclined portion of the push member and the inclined portion of the rotating cam can be brought into contact with each other, and the protruding portion of the rotating cam is used as a locking portion of the rear shaft. It is configured to be able to be locked, and a coil spring is stretched between the inner shaft and the rotating cam with a mounting load that is weaker than the mounting load of the return spring, and the front shaft and the rear shaft are screwed together to form the shaft cylinder. A retractable mechanical pencil characterized by

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