JP2009172881A - Composite writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite writing utensil, the durability of which can be improved, by a method wherein the shock resistance under the condition that shock is applied to its tip with one writing spindle extended is improved. <P>SOLUTION: This composite writing utensil is equipped with a cam body 22, which is unrotatable to a rear barrel, and sliders 32 each connected with the rear end of a writing spindle. In the cam body 22, a forwardly projecting V-shaped cam projection 22b is formed. In addition, a forwardly facing cam surface 22c is formed along the cam projection 22b. At the apex portion of the cam projection of the cam surface 22c, a securing recess 22d is formed. The securing recess 22d is composed of a pair of slanting surfaces 22f and 22f and a straight part 22e formed therebetween. In the slider 32, a backwardly projecting V-shaped cam 32a is formed and further a backwardly facing slidingly contacting surface 32b is formed along the cam 32a and furthermore a straight part 32c is formed at the tip of the cam 32a. Under the condition that the tip of the writing spindle projects above the tip opening of the barrel in the state that the cam 32a is secured to the securing recess 22d, both the ends of the straight part 32c of the cam 32a strikingly contact with the slanting surfaces 22f of the securing recess 22d. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention stores, for example, a plurality of arbitrary writing axes such as a pole pen writing axis, a mechanical pencil writing axis, an eraser writing axis, a computer input writing axis, an eyeliner writing axis, and the like. More particularly, the present invention relates to a composite writing instrument that can improve the impact resistance when an impact force acts on the tip of the writing shaft.

  Conventionally, what was described in patent document 1 is known as this kind of composite writing instruments. In this composite writing instrument, a plurality of writing shafts are housed in a shaft tube, and the shaft tube includes a front shaft tube and a rear shaft tube that can rotate relative to the front shaft tube. Yes. In the shaft cylinder, there are provided a cam main body that cannot rotate with respect to the rear shaft cylinder, and a slider that cannot rotate with respect to the front shaft cylinder and is connected to the rear end portion of each writing shaft. Yes. The cam body is formed with a V-shaped cam projection that protrudes forward, and a cam surface that faces forward along the cam projection is formed at the apex portion of the cam projection on the cam surface. A locking portion is formed. Further, the slider is formed with a V-shaped cam projecting rearward, and a sliding contact surface facing rearward is formed along the cam. The sliding contact surface is formed on the cam surface. It is pressed. By the relative rotation between the rear barrel and the front barrel, the sliding surface of the cam slides on the cam surface and one cam is locked to the locking portion, thereby selectively The tip of the writing shaft connected to the slider provided with the cam projects from the tip opening of the shaft tube.

JP 2005-161829 A

  However, in the above-described conventional composite writing instrument, when the composite writing instrument falls and an impact acts on the tip of the writing shaft with the tip of the writing shaft protruding from the opening of the tip of the shaft, the impact force is camped from the slider. There is a problem that the cam body breaks as it is transmitted to the body.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a composite writing instrument that can improve impact resistance and durability.

In order to achieve the above object, the invention according to claim 1 of the present invention is characterized in that a plurality of writing shafts are accommodated in a shaft cylinder, and a tip of one writing shaft is selectively selected from the plurality of writing shafts. In a composite writing instrument that can protrude from the tip opening of the shaft tube,
A cam body and a slider connected to the rear end of each writing shaft;
The cam body is formed with a V-shaped cam projection that protrudes forward, and a cam surface that faces forward along the cam projection is formed at the apex portion of the cam projection on the cam surface. Has a locking recess,
The slider has a V-shaped cam that protrudes rearward, and a sliding contact surface that faces rearward along the cam.
By the relative rotation between the cam body and the slider, the sliding contact surface slides on the cam surface, and one cam is locked to the locking recess, whereby the cam is selectively provided. The tip of the writing shaft connected to the slider protrudes from the tip opening of the shaft tube,
The locking recess comprises a pair of inclined surfaces and a linear portion formed between them, and a linear portion is formed at the tip of the cam,
In a state where the cam is locked in the locking recess, both ends of the linear portion of the cam abut against the inclined surface of the locking recess.

  The invention according to claim 2 is characterized in that a gap is formed between the straight portion of the cam and the straight portion of the locking recess in a state where the cam according to claim 1 is locked to the locking recess. And

  According to the present invention, when an impact force acts on the tip of the writing shaft, the force is transmitted from the writing shaft to the slider. At this time, force acts on the inclined surface of the locking recess of the cam body from both ends of the cam formed on the slider, and the force is divided into a force along the inclined surface and a force perpendicular to the inclined surface, thereby avoiding stress concentration. be able to. Then, the locking recesses of the cam body are elastically deformed so that the cams widen the inclined surfaces. As a result, the impact force is absorbed to prevent the cam body from being damaged.

  According to the invention described in claim 2, when the impact force is applied due to the gap between the straight portion of the cam and the straight portion of the locking recess, the cam can enter the depth of the locking recess. The locking recess can be elastically deformed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view showing an embodiment of the composite writing instrument of the present invention. In the figure, the composite writing instrument 10 includes a shaft cylinder 12. The shaft tube 12 includes a front shaft tube 14 and a rear shaft tube 16.

  A plurality (three in this example) of writing shafts 30, 30, 30 are accommodated in a shaft cylinder 12 including a front shaft cylinder 14 and a rear shaft cylinder 16. In this example, one writing shaft 30 may be a mechanical pencil writing shaft, and the remaining two writing shafts 30 may be ball pen writing shafts of different colors, but the invention is not limited to this, and an eraser writing shaft including them. Any combination of writing axes such as a writing axis for computer input and an eyeliner writing axis can be used.

  The tip opening 14a of the tip barrel 14 becomes the tip opening of the barrel 12, and any one of the tips of the plurality of writing shafts 30, 30, 30 protrudes selectively from the tip opening 14a.

  The front barrel 14 and the rear barrel 16 are connected to each other by a fitting barrel 18 so as to be detachable and relatively rotatable. The fitting cylinder 18 is caulked and coupled to a guide cylinder 20 that is rotatably arranged with respect to the rear axle cylinder 16 in the rear axle cylinder 16, and protrudes from the tip of the rear axle cylinder 16. The front barrel 14 is detachably fitted to the front. A fitting tab is appropriately formed at a portion protruding from the tip of the rear barrel 16 of the fitting cylinder 18 to enhance the fitting force, and the front barrel 14 is connected to the fitting cylinder 18. And both are designed to rotate together.

  A cam body 22 is fixed in the rear barrel 16. A locking rod 20a at the rear end of the guide tube 20 is locked to the internal step portion 22a of the cam body 22, and the guide tube 20 is attached so as to be relatively rotatable within the rear shaft tube 16. The cam body 22 may be formed integrally with the rear shaft cylinder 16.

  A guide groove 20b extending in the axial direction is formed in the guide cylinder 20 corresponding to each writing shaft 30, and a slider 32 connected to the rear end of the writing shaft 30 is slidable in the guide groove 20b. Be placed. A spring 34 wound around the writing shaft 30 is inserted between the slider 32 and the partition portion 20c provided at the intermediate portion of the guide tube 20, and the spring 34 moves the slider 32 backward. Always energized.

  The cam body 22 is formed with a cam projection 22b protruding forward, an end surface 22c serving as a cam surface facing forward along the cam projection 22b extends in a V shape, and the end surface 22c. Is continuous from both ends of the cam projection 22b in the circumferential direction. A locking concave portion 22d as a locking portion is formed at the V-shaped apex portion of the end face 22c.

  Specifically, as shown in FIG. 4, the locking recess 22d has a central portion of the recess that is not a curve as in the prior art, but a straight portion 22e, and a pair of inclined sides on both sides of the straight portion 22e. Surfaces 22f and 22f are formed. The pair of inclined surfaces 22f and 22f approach each other as they go deeper. The locking recess 22d is elastically deformable in a direction in which the pair of inclined surfaces 22f and 22f are separated from each other.

  On the other hand, as shown in FIG. 5, the cam 32a is formed in the outer peripheral surface of the slider 32, and the sliding contact surface 32b facing back is extended in V shape along this cam 32a. The sliding contact surface 32b of the cam 32a of the slider 32 urged backward by the spring 34 is pressed against the end surface 22c and is in sliding contact with the end surface 22c.

  The tip of the slidable contact surface 32b extending in a V shape is not a curve as in the prior art, but is a straight portion 32c, and both ends of the straight portion 32c are curved surfaces with a small radius of curvature. Preferably, the length of the straight portion 32c is larger than the length of the straight portion 22e.

  An eraser cradle 24 is fixed to the rear of the cam main body 22, an eraser 26 is inserted into the eraser cradle 24, and an eraser cover 28 is attached. Further, the base of the clip 29 is sandwiched between the eraser cradle 24 and the rear end of the rear barrel 16, and the main body of the clip 29 extends along the rear barrel 16.

  The operation of the composite writing instrument 10 configured as described above will be described.

  When the rear barrel 16 is rotated with respect to the front barrel 14 from the state shown in FIGS. 3 and 6B, the cam body 22 fixed to the rear barrel 16 is rotated together. On the other hand, since the fitting tube 18 that rotates integrally with the front shaft tube 14 and the guide tube 20 connected to the fitting tube 18 do not rotate, there is no rotation between the guide tube 20 and the cam body 22. Relative rotation occurs. Accordingly, relative rotation occurs between the slider 32 in the guide groove 20b of the guide tube 20 and the cam body 22, and the sliding contact surface 32b of the cam 32a of the slider 32 moves along the end surface 22c of the cam body 22. . Thus, when the cam 32a of one slider 32 reaches the locking recess 22d of the end surface 22c of the cam projection 22b of the cam main body 22, and is locked to the locking recess 22d, the slider 32 and the slider 32 are coupled thereto. The writing shaft 30 is maintained in the advanced state, and the tip of the writing shaft 30 protrudes from the tip opening 14a of the front barrel 14 and is used (FIGS. 2 and 6A).

  The cam 32a of the other slider 32 reaches the flange portion of the cam projection 22b of the end surface 22c of the cam main body 22, and the slider 32 and the writing shaft 30 connected thereto are maintained in the retracted state.

  When the cam 32a and the locking recess 22d are locked, as shown in FIG. 7A, both ends of the straight portion 32c of the cam 32a are in contact with the inclined surfaces 22f of the locking recess 22d. That is, the straight portion 32c of the cam 32a is not in direct contact with the straight portion 22e of the locking recess 22d, and a slight gap is formed between them.

  In this way, when one writing shaft 30 is in the advanced state, if the composite writing instrument 10 falls and an impact is applied to the tip of the writing shaft 30, the impact force is transmitted to the slider 32. Conventionally, as shown in FIG. 8, since the tip of the cam is thin, there is a problem that stress concentrates on the cam body and cracks and tears from the central portion. In contrast, in the present invention, both ends of the linear portion of the cam 32 a of the slider 32 are in contact with the inclined surface 22 f of the locking recess 22 d of the cam body 22, so that the writing shaft 30 extends along the axial direction. The impact force is divided into a force along the inclined surface 22f and a force perpendicular to the inclined surface 22f, and concentration of stress can be avoided. Then, the cam 32a of the slider 32 is moved until the cam 32a sinks into the locking recess 22d and the linear portion 32c of the cam 32a comes into contact with the linear portion 22e of the locking recess 22d as shown in FIG. 7B. Pushes the locking recess 22d. In this way, the cam 32a pushes the inclined surface 22f of the locking concave portion 22d so as to be elastically deformed and sinks, whereby the impact force can be buffered and the cam body 22 can be prevented from being damaged. When the impact force is released, the original state can be restored.

  When it is desired to store the protruding writing shaft 30 after it has been used, when the rear barrel 16 is rotated a little strongly with respect to the front barrel 14 again, the engaging recess 22d of the cam projection 22b of the cam body 22 is engaged. When the cam 32a of the slider 32 that has stopped escapes from the locking recess 22d and moves on the end face 22c, a state as shown in FIG. 6B is reached, and all the writing shafts 30 are retracted. . In this way, a plurality of writing shafts 30 in the shaft tube 12 is rotated and moved along the circumferential direction of the shaft tube 12, so that one writing shaft 30 sequentially protrudes from the tip of the shaft tube 12, The state where all the writing axes 30 are retracted can be repeated.

  As described above, the composite writing instrument of the present invention can have a structure that is strong against impact force, so that durability can be improved.

  In the above embodiment, the shaft cylinder is composed of the front shaft cylinder and the rear shaft cylinder, and the relative rotation between the slider and the cam main body is generated by the relative rotation. However, the present invention is not limited to this. A shaft cylinder in which the front shaft cylinder and the rear shaft cylinder are integrated, and the cam main body protrudes from the rear end of the shaft cylinder, and the cam main body rotates with respect to the shaft cylinder. The present invention can be similarly applied to a composite writing instrument configured to generate a relative rotation between the cam body and the cam body.

It is a longitudinal cross-sectional view showing embodiment of the composite writing instrument of this invention (In addition, only the upper part is sectional drawing about the rear part of a guide cylinder in the figure). It is explanatory drawing showing the relationship between the cam main body, a guide cylinder, a slider, and a front shaft cylinder in the state where one writing shaft protrudes, (a) is a view seen from the cam projection side of the cam main body, and (b) is (a). It is the figure seen from the opposite side. It is explanatory drawing showing the relationship of a cam main body, a guide cylinder, a slider, and a front-axis | shaft cylinder in the state which all the writing shafts retracted, (a) is the figure seen from the cam protrusion side of the cam main body, (b) is ( It is the figure seen from the opposite side to a). It is an expansion plane expanded view showing the vertex vicinity of the cam protrusion of a cam main body. It is a top view of a slider. It is a figure showing the relationship between a cam main body and a cam, (a) is the state in which one writing shaft protruded, (b) is the state in which all the writing shafts retracted. It is an enlarged view showing the state in which the cam of the slider is locked in the locking recess of the cam body, (a) shows a normal state, and (b) shows a state where an impact is applied. FIG. 8 is a view corresponding to FIG. 7 illustrating a state in which an impact is applied in the conventional configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Composite writing instrument 12 Shaft cylinder 14 Lead axle cylinder 14a Tip opening 16 Rear axle cylinder 22 Cam main body 22b Cam protrusion 22c End surface (cam surface)
22d Locking recess 22e Linear portion 22f Inclined surface 30 Writing shaft 32 Slider 32a Cam 32b Sliding surface 32c Linear portion

Claims (2)

In a composite writing instrument in which a plurality of writing shafts are housed in a shaft cylinder, and the tip of one writing shaft can be selectively protruded from the tip opening of the shaft cylinder among the plurality of writing shafts,
A cam body and a slider connected to the rear end of each writing shaft;
The cam body is formed with a V-shaped cam projection that protrudes forward, and a cam surface that faces forward along the cam projection is formed at the apex portion of the cam projection on the cam surface. Has a locking recess,
The slider has a V-shaped cam that protrudes rearward, and a sliding contact surface that faces rearward along the cam.
By the relative rotation between the cam body and the slider, the sliding contact surface slides on the cam surface, and one cam is locked to the locking recess, whereby the cam is selectively provided. The tip of the writing shaft connected to the slider protrudes from the tip opening of the shaft tube,
The locking recess comprises a pair of inclined surfaces and a linear portion formed between them, and a linear portion is formed at the tip of the cam,
A composite writing instrument, wherein both ends of the linear portion of the cam abut against the inclined surface of the locking recess in a state where the cam is locked in the locking recess.   2. The composite writing instrument according to claim 1, wherein a gap is formed between the linear portion of the cam and the linear portion of the locking recess in a state where the cam is locked in the locking recess.

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