JP2010094954A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which prevents a slider from becoming rickety and permits stable writing. <P>SOLUTION: The slider 51 is rotated by a prescribed angle in one direction around an axial line L in accordance with reciprocation in the axial line L direction. In the mechanical pencil 40, the slider 51 retreats against energizing force of a spring (energizing means) 55 via a writing core P and a core retention part 52 by writing pressure, and the slider 51 is rotated by a predetermined pitch in one direction around the axial line L by a feeding mechanism H1 and the writing pressure. Thereafter, when the writing core P is lifted from a paper surface during writing, the writing pressure is released, the slider 51 is caused to advance by the feeding mechanism H1 and the spring 55, and, accompanying the advance, the slider 51 is rotated by a predetermined pitch in one direction around the axial line L. The mechanical pencil implements a knock type in collaboration with a chuck part 46, a guide surface 47a of a chuck holder and a ball BL. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mechanical pencil that uses a writing pressure to rotate a writing core.

  When writing with a mechanical pencil, the writing core decreases as the writing progresses, and the thickness of the drawn line is not constant, and the darkness of the drawn line also changes. And although a general user writes while rotating the shaft cylinder again, it is difficult to make the thickness and darkness of a drawn line constant, and it is a reality that writing efficiency is reduced. Therefore, in WO 2007/142135 pamphlet, a mechanical pencil for solving the reduction of the writing core is disclosed. In this mechanical pencil, a chuck unit is arranged in the rotor, and the rotor is provided with a pair of sawtooth-shaped first and second rotating cam surfaces on the front and rear sides, and the shaft cylinder side has the first and first rotating cam surfaces. First and second fixed cam surfaces facing the two rotating cam surfaces are provided, and the first fixed cam surface and the second fixed cam surface are shifted by a half pitch in the circumferential direction. At the time of writing, the rotor is moved back by a half pitch by writing pressure, and the rotor is rotated by a half pitch by releasing the writing pressure and the rotor is advanced by a spring force. . By continuing this operation, the writing core is reduced by half while rotating the writing core by half a pitch during writing.

International Publication No. 2007/142135 Pamphlet

In the above-described conventional mechanical pencil, the rotor is separated from the slider provided in the base. Therefore, during writing, the writing core always keeps rotating every half pitch in the core insertion hole of the rubber holding chuck (core holding part) fixed in the slider, so the writing core rubs against the wall surface of the core insertion hole. As a result, the core holding force of the holding chuck against the writing core may be weakened. Therefore, when the writing lead is extended, the holding chuck does not easily perform the stopper function, and there is a possibility that the writing lead cannot be extended due to the knocking operation. Therefore, in order to avoid such a situation, it is possible to integrate the rotor and the slider.
However, when the rotor and the slider are integrated, the slider is pressed against the base due to the accumulated error when assembling the parts up to the cam (rotor, chuck unit, slider, and holding chuck). There is a possibility that it cannot be rotated. Therefore, the size of the opening provided in the base for projecting the tip of the slider is made considerably larger than the diameter of the tip of the slider so that a large gap is formed between the wall surface of the opening of the base and the tip of the slider. It is necessary to form. As a result, the slider becomes loose when writing, which makes writing unstable. In addition, the length from the tip of the slider to the cam is a factor that causes backlash when writing. Such instability at the time of writing is not preferable at the time of drafting when high writing accuracy is required.

  An object of the present invention is to provide a mechanical pencil that eliminates rattling of a slider and enables stable writing.

The present invention is a mechanical pencil capable of feeding a writing core by a predetermined amount in the axial direction.
A chuck holder that is disposed in the shaft cylinder and reciprocates in the axial direction;
A chuck portion that is housed in the chuck holder and reciprocates in the axial direction;
A funnel-shaped guide surface provided on the inner wall surface on the front side of the chuck holder;
A ball disposed between the chuck portion and the guide surface;
A slider having a core holding part for holding the writing core, and reciprocating in the axial direction;
A feed mechanism that rotates the slider in a predetermined direction in one direction around the axis along with the reciprocating movement of the slider in the axial direction;
And an urging means for urging the slider toward the front.

In this mechanical pencil, a slider having a lead holding part for holding a writing lead rotates at a predetermined angle in one direction around the axis as it reciprocates in the axial direction. In the present invention, since the writing core is rotated together with the core holding portion by the rotation of the slider, the writing core does not rotate while rubbing against the wall surface of the core insertion hole of the core holding portion. The core holding ability of the core holding part with respect to is not weakened. Further, since the slider and the chuck holder are not integrated, it is difficult to generate an accumulated error when assembling the components. As a result, the wall surface of the opening provided on the base and the slider to project the tip of the slider There is no need to leave a large gap between them. Therefore, the writing can be stabilized without causing a backlash of the slider at the time of writing. In particular, it is preferable at the time of drafting when high writing accuracy is required.
In this mechanical pencil, the slider is retracted against the urging force of the urging means via the writing core and the stylus holding portion by the pen pressure, and the slider is moved at a predetermined angle in one direction around the axis by the feed mechanism and the pen pressure. Rotate. After that, when the writing core is lifted from the paper surface during writing, the writing pressure is released, and the slider is advanced by the urging means, and accordingly, the slider is centered on the axis by the urging force of the feeding mechanism and the urging means. It rotates a predetermined angle in one direction. Thus, the slider repeats such a series of operations, so that the slider continues to rotate at a predetermined angle, thereby preventing the writing core from being partially reduced during writing.
In addition, the rotation of the writing core following the rotation of the slider is performed by rotating the writing core with respect to the chuck portion about the axis, rotating the chuck portion with respect to the chuck holder about the axis, This is preferably achieved by measures such as rotating the chuck holder about the axis.
By the cooperation of the chuck portion, the guide surface of the chuck holder, and the ball, the mechanical pencil can have a knock function, which is also a core feeding function suitable when the slider and the chuck holder are separated and independent.

In addition, it is preferable that the writing core rotates about the axis with respect to the chuck portion.
This is a structure suitable for rotating the writing core following the rotation of the slider.

Further, it is preferable that the chuck holder rotates about the axis with respect to the shaft cylinder.
This is a structure suitable for rotating the writing core following the rotation of the slider.

Further, it is preferable that the chuck portion rotates about the axis with respect to the chuck holder.
This is a structure suitable for rotating the writing core following the rotation of the slider.

  According to the present invention, rattling of the slider is eliminated and stable writing can be performed.

  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”.

  As shown in FIG. 1, the mechanical pencil 40 is a knock-type writing instrument that can push out the writing core P by a predetermined amount in the direction of the axis L by pushing a knock cap (not shown) arranged at the rear end. . The mechanical pencil 40 has a resin shaft cylinder 42, and a rubber or resin grip 43 for preventing finger slipping is fixed to the outer surface of the shaft cylinder 42.

  A cylindrical core case 44 extending substantially over the entire length is inserted into the shaft cylinder 42, and a chuck portion 46 for holding and feeding the writing core P is disposed on the distal end side of the core case 44. A knock cap (not shown) is detachably attached to the rear end of the lead case 44. The chuck portion 46 includes chuck halves 46 a and 46 b that are divided into two along the axis L. The writing core P is sandwiched by closing the front sides of the chuck halves 46a and 46b, and the writing core P is released by opening the front sides of the chuck halves 46a and 46b.

  A cylindrical chuck holder 47 is inserted between the shaft cylinder 42 and the core case 44, and the chuck holder 7 reciprocates in the axis L direction. A cylindrical assist portion 45 is disposed between the chuck holder 47 and the shaft cylinder 42, and a spring for biasing the chuck holder 47 forward between the assist portion 45 and the chuck holder 47. 56 is interposed.

  On the front side of the chuck holder 47, a funnel-shaped guide surface 47a is formed on the inner wall surface, and the guide surface 47a expands toward the front end. Further, a ball receiving recess 48 is formed on the outer surface side of each chuck half 46a, 46b, and the ball BL disposed in the ball receiving recess 48 contacts the guide surface 47a of the chuck holder 47, and the guide surface The chuck portion 46 is easily moved along 47a.

  When the chuck portion 46 moves forward along the guide surface 47 a via the ball BL, the front sides of the chuck halves 46 a and 46 b are opened, and the writing core P is released from the chuck portion 46. When the chuck portion 46 moves backward along the guide surface 47 a via the ball BL, the front sides of the chuck half portions 46 a and 46 b are closed, and the writing core P is sandwiched by the chuck portion 46.

  Further, a resin cap 50 is connected to the tip of the shaft cylinder 42 by a screw portion 50e, and a resin slider 51 that reciprocates in the direction of the axis L is disposed in the cap 50. The slider 51 is spaced apart from the front of the chuck holder 47 and connects the slider 51 and the chuck portion 46 by a spring (biasing means) 55. The slider 51 includes a cup-shaped main body 51a and a pipe-shaped tip 51b protruding from the main body 51a. The tip 51 b protrudes from an opening 50 a provided at the tip of the base 50. A rubber core holding portion 52 that functions as a detent of the writing core P when knocked is press-fitted into the recess 51 d of the main body 51 a of the slider 51, and a core insertion hole 52 a is formed at the center of the core holding portion 52. (See FIG. 4).

  Since the chuck part 46 does not sandwich the writing core P in the normal state, the writing core P is in a free state with respect to the chuck part 46. When writing pressure is applied to the writing core P during writing, the slider 51 is retracted via the core holding portion 52, and the chuck portion 46 is retracted by the spring 55, so that the ball BL slides along the guide surface 47a. However, the chuck portion 46 finally strongly holds the writing core P.

  When the knock cap is pushed with a finger from the normal state shown in FIG. 1, the protrusion 47 b provided at the rear end of the chuck holder 47 is pushed forward by the step portion 44 c provided in the core case 44. Then, the front end 47 d of the chuck holder 47 contacts the stepped portion 50 d of the base 50. Further, when the knock cap is continuously pressed, the protrusion 47b gets over the stepped portion 44c and the stepped portion 44a comes into contact with the rear end of the chuck portion 46.

  When the knock cap is further pressed, the chuck portion 46 is gradually opened while moving forward, the writing lead P is released from the chuck portion 46, and the feeding of the writing lead P is completed. And the front-end | tip part 44b of the lead case 44 enters between the writing lead P and the chuck | zipper part 46, and the chuck | zipper part 46 is opened completely.

  Thereafter, when the finger force is removed, the chuck portion 46 is returned together with the lead case 44 by the spring 55. At this time, the return of the writing core P is regulated by the rubber core holding portion 52, and the writing core P keeps its position by the core holding portion 52 without the writing core P following the retreat of the chuck portion 46. . Further, since the chuck portion 46 is pressed against the chuck holder 47 via the ball BL by the tip end portion 44b of the lead case 44, the chuck holder 47 can be retracted together with the retracting of the chuck portion 46.

  Such a knock-type mechanical pencil 40 has a feed mechanism H1 for preventing the writing core P from being partially reduced.

  As shown in FIGS. 1, 3, and 4, the feed mechanism H <b> 1 rotates the slider 51 at a predetermined angle in one direction around the axis L as the slider 51 reciprocates in the axis L direction. It is for making it happen.

  The feed mechanism H1 is provided on the front outer surface side of the main body portion 51a (the bulging portion 51c) of the slider 51, and has a sawtooth-shaped first movable side mesh arranged at an equal pitch around the axis L. Is provided on the rear outer surface side of the body portion 61a of the slider 51 and the main body portion 51a (bulged portion 51c) of the slider 51, and is symmetrical with the first movable-side meshing portion 61 in the direction of the axis L, and annularly about the axis L Sawtooth-shaped second movable-side meshing portions 62 arranged at an equal pitch, and provided on the base 50 side, face the first movable-side meshing portion 61, and have an equal pitch around the axis L The sawtooth-shaped first fixed-side meshing portion 71 arranged on the base 50 and the base 50 side are faced to the second movable-side meshing portion 62 and arranged at an equal pitch around the axis L. Second-side fixed sawtooth shape Consisting of engaging portion 72.

  And when the full length in the circumferential direction of each tooth part 61a, 62a, 71a, 72a of each meshing part 61, 62, 71, 72 is 1 pitch, it is 2nd movable with respect to the 1st movable side meshing part 61. The side meshing portions 62 are arranged without a phase shift in the circumferential direction, and the second fixed side meshing portion 72 is arranged with a phase shifted by 1/4 pitch in the circumferential direction with respect to the first fixed side meshing portion 71. ing. In this case, for example, when each of the meshing portions 61, 62, 71, 72 includes 36 tooth portions 61a, 62a, 71a, 72a, the rotation angle corresponding to one pitch is 10 degrees.

  In such a feeding mechanism H1, the first and second movable side engaging portions 61 and 62 are respectively provided on both end surfaces of the ring-shaped bulging portion 51c protruding in the radial direction at the rear end of the main body portion 51a of the slider 51. Is formed. Further, on the inner wall surface of the base 50, a ring-shaped recess 50c into which the bulging portion 51c of the slider 51 is inserted is formed, and the first and second fixed-side meshing portions 71, 72 form the recess 50c. It is formed on each end face.

  Further, the main body 51 a of the slider 51 and the tip of the chuck portion 46 are connected by a spring (biasing means) 55, and the slider 55 biases the slider 51 forward. The spring 55 is inserted into a recess 51 d formed on the rear end side of the slider 51, and is located on the inner side of the first and second movable side engaging portions 61 and 62.

  When the writing core P is pressed against the paper surface during writing, the slider 51 is moved in the direction of the arrow A by the writing pressure as shown in FIG. After that, as shown in FIG. 5B, the tooth portion 62a of the second movable side meshing portion 62 slides on the surface of the tooth portion 72a of the second fixed side meshing portion 72 by the writing pressure, and the slider 51 moves in the direction of arrow B and stops. As a result, the slider 51 rotates by a quarter pitch about the axis L, and accordingly, the writing core P rotates by a quarter pitch while being held by the core holding portion 52.

  Further, when the writing core P slightly floats from the paper surface during writing, the writing pressure is released, and the slider 51 advances in the direction of arrow C by the spring (biasing means) 55 as shown in FIG. . Thereafter, as shown in FIG. 5 (4), the tooth portion 61a of the first movable-side meshing portion 61 slides on the surface of the tooth portion 71a of the first fixed-side meshing portion 71 by the biasing force of the spring 55. Then, the slider 51 moves in the direction of arrow D and stops. As a result, the slider 51 rotates by 3/4 pitch in one direction around the axis L, and accordingly, the writing core P rotates by 3/4 pitch while being held by the core holding portion 52.

  When the slider 51 repeats such a series of operations during writing, the slider 51 continues to rotate, thereby preventing the writing core P from being partially reduced during writing. The reason why the slider 51 rotates by 3/4 pitch at the first fixed-side meshing portion 71 side while the slider 51 rotates by only 1/4 pitch at the second fixed-side meshing portion 72 is that the spring 55 chucks. This is because when the portion 46 moves backward, the chuck portion 46 moves in the closing direction via the ball BL, so that the rotation of the slider 51 must be completed within a short time. In this case, the second fixed side engaging portion 72 may be arranged with a phase shifted by 1/8 pitch in the circumferential direction with respect to the first fixed side engaging portion 71.

  Further, during writing, as shown in FIG. 6, the chuck portion 46 follows the advance / retreat of the slider 51 by the spring 55, and the chuck holder 47 moves the ball BL to the advance / retreat of the chuck portion 46 by the spring 56. Follow through. Such follow-up of the chuck holder 47 is a device for extending the rotation time of the writing core P as much as possible so that the writing core P is not suddenly caught by the chuck portion 46 when the chuck portion 46 is retracted. It is. Furthermore, since the slider 51 and the feed mechanism H1 are provided in the base 50, and the base 50 is detachable with respect to the shaft tube 42, even when the feed mechanism H1 is damaged, the base 50 is simply replaced. Well, maintenance is very good.

  To smoothly rotate the writing core P as the slider 51 rotates, (a) the chuck holder 47 is rotated about the axis L with respect to the shaft cylinder 42, and (b) the chuck holder 47 is rotated. On the other hand, it is conceivable to rotate the chuck portion 46 about the axis L, and (c) rotate the writing core P about the axis L with respect to the chuck portion 46.

  The above (A) will be described. As shown in FIGS. 1, 7, and 8, the two claw portions 45 a protruding in the radial direction from the assist portion 45 enter the concave portion 42 a of the shaft tube 42, so that the assist portion 45 has the axis L Does not rotate to the center. On the other hand, the chuck holder 47 is rotatably inserted in the assist part 45. Therefore, the chuck holder 47 can be freely rotated around the axis L with respect to the shaft cylinder 42.

  Regarding (b), that is, rotating the chuck portion 46 about the axis L with respect to the chuck holder 47 will be described. As shown in FIG. 1, since the ball BL is disposed between the chuck holder 47 and the chuck portion 46, the chuck portion 46 can be freely rotated in the circumferential direction with respect to the chuck holder 47.

  Regarding (c), since the chuck portion 46 does not sandwich the writing core P in the normal state, the writing core P can be rotated around the axis L with respect to the chuck portion 46.

  The mechanical pencil 40 has a function of rotating the chuck holder 47 around the axis L with respect to the shaft cylinder 42, a function of rotating the chuck portion 46 around the axis L with respect to the chuck holder 47, and a function of Thus, by having the function of rotating the writing core P around the axis L, the writing core P can be reliably and smoothly rotated by the rotation of the slider 51. Note that any of the functions described above may be selectively employed.

  As another modification, as shown in FIG. 9, the chuck holder 47 cannot be rotated with respect to the shaft cylinder 42 by inserting the claw portion 47 e of the chuck holder 47 into the opening 45 a of the assist portion 45. Also good.

  In the mechanical pencil 40, the slider 51 disposed in the base 50 is spaced apart from the front of the chuck holder 7 and reciprocates in the direction of the axis L. Rotate every predetermined angle in the direction. Accordingly, since the writing core P is rotated together with the core holding portion 52 by the rotation of the slider 51, the writing core P does not rotate while rubbing against the wall surface of the core insertion hole 52 a of the core holding portion 52, and writing. The lead holding force of the lead holding part 52 with respect to the lead P does not become weak. Furthermore, since the slider 51 and the chuck holder 7 are not integrated, it is difficult to generate an accumulated error when assembling the components. As a result, an opening provided in the base 50 for projecting the tip of the slider 51 is provided. It is not necessary to leave a large gap between the wall surface forming 50a and the slider 51, and writing can be stabilized without causing play of the slider 51 during writing. In particular, it is preferable at the time of drafting when high writing accuracy is required.

  In the mechanical pencil 40, the slider 51 is retracted against the biasing force of the spring (biasing means) 55 via the writing core P and the core holding portion 52 by the writing pressure, and the slider 51 is moved by the feeding mechanism H1 and the writing pressure. Rotates about 1/4 axis in one direction around the axis L. Thereafter, when the writing core P is lifted from the paper surface during writing, the writing pressure is released, and the slider 51 is advanced by the spring 55. Accordingly, the slider 51 moves the axis L by the urging force of the feeding mechanism H1 and the spring 55. Rotate 3/4 pitch in one direction around the center. During the writing, the slider 51 repeats such a series of operations, so that the slider 51 continues to rotate by a predetermined pitch, thereby preventing the writing core from being partially reduced during the writing.

  It goes without saying that the present invention is not limited to the embodiment described above.

  For example, as shown in FIG. 10, the second fixed-side meshing portion 72 is arranged without a phase shift in the circumferential direction with respect to the first fixed-side meshing portion 71, and is arranged with respect to the first movable-side meshing portion 61. Therefore, the second movable side meshing portions 62 may be arranged with a phase shifted in the circumferential direction.

  The urging means 55 may be an elastic member such as rubber.

  Further, the slider and the chuck holder may be integrated.

  The base may be formed integrally with the shaft tube.

  Moreover, you may integrate in the slider, without making a core holding | maintenance part another component.

It is embodiment of the mechanical pencil which concerns on this invention, and is sectional drawing which shows the state at the normal time of a mechanical pencil. It is sectional drawing which shows the mechanical pencil at the time of knocking. It is a perspective view which shows a slider. It is sectional drawing of a slider. It is the schematic which shows the rotation state of a slider. It is sectional drawing which shows the mechanical pencil at the time of writing. It is sectional drawing which follows the XVII-XVII line of FIG. It is sectional drawing which follows the XVIII-XVIII line of FIG. It is sectional drawing which shows the other modification in the position corresponding to the VIII-VIII line of FIG. It is a principal part enlarged view which shows other embodiment of a mechanical pencil.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 40 ... Mechanical pencil, 42 ... Shaft cylinder, 46 ... Chuck part, 47 ... Chuck holder, 47a ... Guide surface, 50 ... Base, 51 ... Slider, 52 ... Core holding part, 55 ... Spring (biasing means), 61 ... 1st movable side meshing part, 62 ... 2nd movable side meshing part, 71 ... 1st fixed side meshing part, 72 ... 2nd fixed side meshing part, P ... Writing core, L ... Axis, H1 ... Feed Mechanism, BL ... Ball.

Claims (4)

In a mechanical pencil that can draw out the writing core by a predetermined amount in the axial direction,
A chuck holder that is disposed in a shaft cylinder and reciprocates in the axial direction;
A chuck portion housed in the chuck holder and reciprocating in the axial direction;
A funnel-shaped guide surface provided on the front inner wall surface of the chuck holder;
A ball disposed between the chuck portion and the guide surface;
A slider having a core holding part for holding the writing core, and reciprocating in the axial direction;
A feed mechanism that rotates the slider in a predetermined direction in one direction around the axis, as the slider reciprocates in the axis direction;
A mechanical pencil comprising biasing means for biasing the slider forward   The mechanical pencil according to claim 1, wherein the writing core rotates about the axis with respect to the chuck portion.   The mechanical pencil according to claim 1 or 2, wherein the chuck holder rotates about the axis with respect to the shaft cylinder.   The mechanical pencil according to any one of claims 1 to 3, wherein the chuck portion rotates about the axis with respect to the chuck holder.

Images