JP6034062B2 - mechanical pencil - Google Patents

Description

  The present invention relates to a mechanical pencil capable of feeding a writing core by a predetermined amount in the axial direction by knocking.

  Conventionally, as a technology in such a field, there is Japanese Utility Model Publication No. 61-118784. The mechanical pencil described in this publication is a knock type, and a knock unit capable of feeding a writing core by a predetermined amount in the axial direction is accommodated in the shaft cylinder. This knock unit is provided with a tail plug cap at the rear end to allow the writing core to be accommodated, a chuck portion that is fixed to the front end of the core pipe to enable the holding of the writing core, and the chuck portion. A chuck holder that accommodates the chuck holder, a chuck clamping cup that enables opening and closing of the tip of the chuck holder, and a compression coil spring that biases the core pipe toward the rear.

  In such a knock-type mechanical pencil, when the tail plug is knocked with a finger, the chuck tightening cup is forcibly stopped in the middle of the knock, thereby opening the chuck portion, and the writing core is moved to the chuck portion. Freed from pinching. By such an operation, a writing core having a predetermined length is fed out from the tip of the base. Then, when the finger is released from the tail plug, the core pipe is retracted by the compression coil spring, and the chuck part is retracted while maintaining the open state, and the tip of the chuck part enters the chuck tightening cup. The chuck portion is closed, and the writing core is pinched by the chuck portion to enter a standby state. With such a series of knocking operations, the writing core is fed out from the tip of the mechanical pencil by a predetermined amount, and the feeding amount of the writing core can be increased according to the number of knocks.

Japanese Utility Model Publication No. 61-118784

  However, the above-described conventional mechanical pencil has a problem in that when excessive writing pressure is applied to the writing core during writing, a portion of the writing core exposed from the base is easily broken. Therefore, the user has been forced to use a writing core with high hardness as a prevention of bending of the writing core.

  An object of the present invention is to provide a mechanical pencil that absorbs writing pressure and prevents the writing core from breaking.

The present invention includes a shaft tube,
A rotation support surface provided on the shaft tube;
A writing structure comprising: a base positioned at a front end of the shaft tube; a knocking unit that includes a feeding mechanism for feeding out the writing core; and a chuck holder that connects the base and the knocking unit. ,
A joint part provided in the writing structure and in sliding contact with the rotation support surface;
A compression coil spring located behind the joint and biasing the writing structure including the joint forward;
I have a,
The joint portion is pressed against the rotation support surface by a compression coil spring .

  In this mechanical pencil, when excessive writing pressure is applied to the writing core at the time of writing, the rotation support surface provided in the shaft cylinder and the joint provided in the writing structure including the knock unit in which the writing core is inserted and arranged The base tilts according to the pen pressure by the cooperation with the part. By such tilting, it is possible to appropriately prevent the writing core from breaking in the core pipe of the knock unit so as to penetrate the base. Furthermore, the base can be tilted, that is, swung while absorbing the writing pressure with the compression coil spring, and the concentration of the load on the portion of the writing core that is exposed from the base is properly absorbed by the compression coil spring. The part which protrudes from is made difficult to break. When excessive writing pressure disappears during writing, the base is easily returned to the original position by a compression coil spring. Further, since the base tilts due to excessive writing pressure, the user can be aware that he / she is writing with excessive writing pressure and can be encouraged to use the writing with appropriate writing pressure. Needless to say, if the writing pressure is high, the writing core will be broken, and if it continues to write with excessive writing pressure, the user will feel tired and writing for a long time becomes difficult. Therefore, the mechanical pencil according to the present invention has an effect of prompting the user to write with an appropriate writing pressure and enabling writing for a long time. By adopting a compression coil spring, the base can be easily tilted according to increase or decrease of the writing pressure, and by changing the elastic force of the compression coil spring, the writing pressure at which the base starts to tilt can be easily changed. be able to.

An elastic body is provided between the writing structure and the shaft tube.
If such a structure is employ | adopted, the elastic force of a compression coil spring can be assisted with an elastic body.

Moreover, the joint part is provided in the chuck holder.
Such a configuration is advantageous for exposing the elastic body to the outside of the shaft tube.

Further, the joint portion is provided on the base.
Such a configuration is advantageous for disposing in the shaft cylinder without exposing the elastic body.

  According to the present invention, the writing pressure can be absorbed to prevent the writing core from breaking.

1 is an external view showing a first embodiment of a mechanical pencil according to the present invention. It is sectional drawing corresponding to FIG. It is an external view which shows the state at the time of use of the mechanical pencil which concerns on 1st Embodiment. FIG. 4 is a cross-sectional view corresponding to FIG. 3. It is an external view which shows 2nd Embodiment of the mechanical pencil which concerns on this invention. It is sectional drawing corresponding to FIG. It is an external view which shows the state at the time of use of the mechanical pencil which concerns on 2nd Embodiment. FIG. 8 is a cross-sectional view corresponding to FIG. 7.

  Hereinafter, preferred embodiments of a mechanical pencil according to the present invention will be described in detail with reference to the drawings. In the following description, the pen tip side is referred to as “front side”.

[First Embodiment]
As shown in FIG. 1 and FIG. 2, the mechanical pencil 1 is a knock type writing instrument capable of feeding out the writing core P by a predetermined amount in the extending direction of the central axis L of the shaft tube 2. The mechanical pencil 1 has an outer shell that serves as a grip for the user, and is disposed in the shaft tube 2. A core feeding mechanism A is disposed on the front end side of the core pipe 11 that houses the writing core P. The knock unit 10 provided and the shaft unit 2 are disposed in front of the shaft cylinder 2 and swing around a rotation point R on the center axis L of the shaft cylinder 2 and are fixed to the core feeding mechanism A of the knock unit 10. And a base 4.

  The shaft cylinder 2 includes a front shaft cylinder 2a used for gripping and a rear shaft cylinder 2b which is fixed to the rear end of the front shaft cylinder 2a and whose rear end is opened. The knock unit 10 includes a core pipe 11 extending in the longitudinal direction in the shaft cylinder 2, a core feeding mechanism A provided on the front end side of the core pipe 11, and an eraser receiver 12 press-fitted into the rear end of the core pipe 11. And an eraser 13 loaded in the eraser receiver, and a tail plug 14 that protects the eraser 13 and into which the eraser receiver 12 is press-fitted.

  The lead-out mechanism A has a rear end press-fitted and fixed in the front end opening of the core pipe 11, a rod-like base portion 16 that allows the writing core P to be inserted, and a press-fit fixed in the front end opening of the base portion 16. In addition, a lead chuck 17 having a slit-shaped chuck portion 17a at the tip, a chuck holder 18 that holds the chuck portion 17a, and is slidably inserted into the front end side of the lead chuck 17 and the base portion 16, and a center A compression coil spring 19 interposed between the chuck holder 18 and the flange portion 16a of the base portion 16 and a chuck holder 18 wound around the axis L and imparting a restoring force to the knock unit 10 And a chuck fastening cup 20 that is inserted into the front end opening and covered with the chuck portion 17a in order to allow the chuck portion 17a to be opened and closed. It is.

  Further, a breaker 24 for applying a frictional force to the writing core P is loaded in the conical base 4, and the base 4 has a step portion for forcibly stopping only the forward movement of the chuck tightening cup 20 when knocking. 4a is formed. The base 4 may be a metal or a resin.

  And the nozzle | cap | die 4 located in the front-end part of the axial cylinder 2, the feeding mechanism A which draws out the writing core P, and the knock unit 10 provided in the axial cylinder 2, the chuck holder which connects the nozzle | cap | die 4 and the knock unit 10 18, a writing structure U is constituted.

  In the writing structure U having such a configuration, the chuck portion 17 a of the lead chuck 17 can be projected from the chuck holder 18 together with the core pipe 11 by knocking the tail plug 14 with a finger. At this time, in a state where the chuck portion 17 a is closed by the chuck tightening cup 20, the holding state of the writing core P is maintained, and the chuck portion 17 a protrudes from the front end of the chuck holder 18 together with the chuck tightening cup 20. Then, in the middle of knocking, the chuck fastening cup 20 is forcibly stopped at the step portion 4a of the base 4, thereby opening the chuck portion 17a and releasing the writing core P from the clamping of the chuck portion 17a. The writing core P is clamped by the breaker 24. With such an operation, the writing core P having a predetermined length is fed out from the tip of the base 4. When the knocking force of the tail plug 14 is released, the core pipe 11 is retracted by the compression coil spring 19, and the chuck portion 17a returns to the original position.

  In constructing the writing structure U, the front end side of the chuck holder 18 of the knock unit 10 is fixed to the base 4 via the screw portion 21, thereby integrating the knock unit 10 and the base 4. It has been. Further, a joint portion 22 formed of a spherical surface with the rotation point R as the center is formed on the rear end side of the chuck holder 18, and this rotatable joint portion 22 is formed on the inner wall surface of the front shaft cylinder 2a. Is supported by a spherical rotation support surface 23. With such a configuration, the base 4 enables tilting around the rotation point R, that is, swinging. Further, the base 4 does not fall off the shaft tube 2 by the joint portion 22.

  Further, a ring-shaped elastic body 26 is loaded between the rear end portion of the base 4 and the front end portion of the front shaft cylinder 2a, and the rear end portion of the base 4 and the front end portion of the front shaft cylinder 2a are elastic. It is in close contact with the body 26. The elastic body 26 is formed of an elastomer, the rear end of the elastic body 26 is inserted into the front opening of the front shaft cylinder 2 a, and the front end of the elastic body 26 is in close contact with the rear end surface of the base 4. .

  Further, a compression coil spring 27 wound around the central axis L is provided behind the joint portion 22 between the rear end surface 18a of the chuck holder 18 and the front end of the rear shaft cylinder 2b. The chuck holder 18 is biased forward by the compression coil spring 27 and presses the joint portion 22 against the rotation support surface 23. Further, by adopting the compression coil spring 27, when the excessive writing pressure is released, the base 4 can be surely returned to the original position, and the base 4 is reliably tilted according to the increase or decrease of the writing pressure. Can be made.

  In the mechanical pencil 1 in which the elastic body 26 is exposed, as shown in FIGS. 3 and 4, when excessive writing pressure is applied to the writing core P during writing, the base 4 rotates according to the writing pressure. The knock unit 10 is tilted from the center axis L to the center axis S around the point R, and the knock unit 10 fixed to the base 4 is also tilted in the shaft cylinder 2. By such tilting, it is possible to appropriately prevent the writing core P from breaking in the core pipe 11 of the knock unit 10 so as to penetrate the base 4. Further, the base 4 can be tilted or swung while absorbing the writing pressure by the compression coil spring 27, and the concentration of the load on the portion of the writing core P exposed from the base 4 is appropriately absorbed by the compression coil spring 27. The writing core P is more difficult to break. When excessive writing pressure disappears during writing, the base 4 is easily returned to the original position by the compression coil spring 27.

  Further, since the base 4 tilts due to excessive writing pressure, the user can be aware that he / she is writing with excessive writing pressure and can be encouraged to use the writing with appropriate writing pressure. Needless to say, if the writing pressure is high, the writing core P will be broken, and if it continues to write with excessive writing pressure, the user will feel tired and writing for a long time becomes difficult. Therefore, the mechanical pencil 1 has an effect of encouraging the user to write with an appropriate writing pressure and enabling writing for a long time.

  By adopting the compression coil spring 27, the base 4 can be easily tilted according to the increase or decrease of the writing pressure, and by changing the elastic force of the compression coil spring 27, the writing pressure at which the base 4 starts to tilt can be changed. It can be easily changed. Further, the elastic body 26 made of an elastomer can assist the elastic force of the compression coil spring 27.

[Second Embodiment]
Next, based on FIGS. 5-8, 2nd Embodiment of the mechanical pencil 30 which concerns on this invention is described, About the same or equivalent structure as 1st Embodiment, the same code | symbol is attached | subjected and it overlaps. Description to be omitted is omitted. The mechanical pencil 30 is configured such that the elastic body 34 is not exposed to the outside. Further, the configuration of the lead feeding mechanism B in the knock unit 10A is the same as that of the mechanical pencil 1 of the first embodiment except for the chuck holder 18A.

  As shown in FIG. 6, a joint portion 32 having a spherical surface centered on the rotation point R is formed at the rear end of the cap 4A. The joint portion 32 that is rotatable is formed on the front side of the shaft tube 2A. It is supported by a spherical rotation support surface 33 formed on the inner wall surface of the front shaft cylinder 2Aa. With such a configuration, the base 4A can be tilted around the rotation point R, that is, can swing.

  Furthermore, a ring-shaped elastic body 34 is loaded between the step 18Aa of the chuck holder 18A of the knock unit 10A and the front end of the rear shaft cylinder 2Ab in the writing structure U1, and the rear end of the chuck holder 18A The elastic body 34 is in close contact with the front end of the rear shaft cylinder 2Ab. The elastic body 34 is formed of an elastomer, the rear end of the elastic body 34 is inserted into the front opening of the rear shaft cylinder 2Ab, and the elastic body 34 is in close contact with the outer peripheral surface of the chuck holder 18A. .

  A compression coil spring 37 wound around the central axis L is provided behind the joint portion 32 between the rear end portion of the base 4A and the front end of the rear shaft cylinder 2Ab. The compression coil spring 37 biases the base 4 </ b> A forward and prevents the base 4 </ b> A from rattling by pressing the joint portion 32 against the rotation support surface 33. Furthermore, by adopting the compression coil spring 37, when the excessive writing pressure is released, the base 4A can be reliably returned to the original position, and the base 4A can be reliably tilted according to the increase or decrease of the writing pressure. Can be made.

  In the mechanical pencil 30 where the elastic body 34 is not exposed, as shown in FIGS. 7 and 8, when excessive writing pressure is applied to the writing core P during writing, the base 4 </ b> A rotates according to the writing pressure. And the knock unit 10A fixed to the base 4A is also tilted in the shaft cylinder 2A. Moreover, since this mechanical pencil 30 has the same effect as the mechanical pencil 1 according to the first embodiment, the description thereof is omitted.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  The shape and location of the elastic bodies 26 and 34 disposed between the writing structures U and U1 and the shaft cylinders 2 and 2A are not limited to the above-described embodiments.

DESCRIPTION OF SYMBOLS 1,30 ... Mechanical pencil 2, 2A ... Shaft cylinder 4, 4A ... Base 10, 10A ... Knock unit 11 ... Core pipe 17 ... Lead chuck 17a ... Chuck part 18, 18A ... Chuck holder 22, 32 ... Joint part 23, 33 ... rotating support surfaces 26, 34 ... elastic bodies 27, 37 ... compression coil springs A, B ... core feeding mechanism L ... center axis P ... writing core R ... rotating point U, U1 ... writing structure

Claims (4)

A barrel,
A rotation support surface provided on the shaft tube;
It is comprised by the nozzle | cap | die located in the front-end part of the said axis | shaft cylinder, the feeding mechanism which pays out a writing core, and provided in the said axis | shaft cylinder, and the chuck holder which connects the said nozzle | cap | die and the said knock unit. A writing structure;
A joint that is provided in the writing structure and slidably contacts the rotation support surface;
A compression coil spring that is located rearward of the joint and biases the writing structure including the joint forward;
I have a,
The mechanical pencil , wherein the joint portion is pressed against the rotation support surface by the compression coil spring .   The mechanical pencil according to claim 1, wherein an elastic body is provided between the writing structure and the shaft tube.   The mechanical pencil according to claim 1, wherein the joint portion is provided in the chuck holder.   The mechanical pencil according to claim 1, wherein the joint portion is provided on the base.

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