Notebook

Abstract

To provide a writing instrument which prevents a tip from falling off even when the writing instrument is subjected to external force, impact, etc. relatively frequently when used at a construction site, for example.SOLUTION: A writing instrument according to one aspect includes a barrel, a tip that is screwed onto the front side of the barrel, a substantially cylindrical writing lead tube that stores a writing lead inside the barrel, a chuck attached to the front side of the writing lead tube to grip the writing lead and send the same forward, a chuck ring that fits with the chuck, a chuck spring that urges the chuck backward with respect to the chuck ring, and a sleeve that accommodates the chuck spring. The sleeve has an elastic portion that elastically deforms in a direction along the axis of the writing instrument. When the tip is screwed into the barrel, the tip comes into contact with the sleeve, compressing the elastic portion. The compression applies a biasing force to the tip, increasing the frictional force of the threaded engagement between the tip and the barrel.SELECTED DRAWING: Figure 2B

Description

Technical Field

[0001] The present invention relates to a writing instrument provided with a feeding mechanism for gripping a refill and feeding it forward.

Background Art

[0002] Conventionally, writing instruments provided with a feeding mechanism for gripping a refill and feeding it forward have been widely used. More specifically, a chuck for gripping the refill and feeding it forward, and a shaft cylinder for accommodating the refill and the chuck are provided, and when a click operation for feeding the chuck forward is performed, a writing instrument (mechanical pencil) configured such that the refill advances is used. Patent Document 1 discloses a technique for generating a jet flow that flows forward in the shaft cylinder when a click operation is performed for such a writing instrument (mechanical pencil).

Prior Art Documents

Patent Documents

[0003] ​​​​​​​​​​​​​​​​​ However, there has been a demand for writing instruments that can use thinner lead than conventional ones, even in situations where the writing instrument is subjected to a relatively large number of external forces and impacts, such as when used on construction sites.

[0005] In view of the above, this disclosure discloses a writing instrument that prevents the tip from falling off even in situations where the writing instrument is subjected to external forces or impacts relatively frequently, such as when used on a construction site. [Means for solving the problem]

[0006] A writing instrument according to one aspect of the present invention includes a barrel, a tip that is screwed onto the front side of the barrel, a substantially cylindrical writing lead tube that houses a writing lead inside the barrel, a chuck attached to the front side of the writing lead tube that grips the writing lead and feeds it forward, a chuck ring that fits with the chuck, a chuck spring that biases the chuck backward relative to the chuck ring, and a sleeve that houses the chuck spring, wherein the sleeve has an elastic portion that deforms elastically in a direction along the axis of the writing instrument, and when the tip is screwed onto the barrel, the tip comes into contact with the sleeve, the elastic portion is compressed, and this compression imparts a biasing force to the tip, increasing the frictional force of the screwing between the tip and the barrel. [Effects of the Invention]

[0007] In one aspect of the present invention, the tip of the writing instrument can be prevented from falling off even in situations where it is subjected to a relatively large number of external forces or impacts, such as when used on a construction site. [Brief explanation of the drawing]

[0008] [Figure 1] Cross-sectional view showing a writing instrument according to an embodiment of the present invention. [Figure 2A] Cross-sectional view showing the tip of the writing instrument in an embodiment where the tip is detached. [Figure 2B]Cross-sectional view showing the tip of the writing instrument in the embodiment with the tip attachment attached. [Figure 3A] Perspective view showing the sleeve of the embodiment [Figure 3B] Plan view of the sleeve of the embodiment, seen from the front. [Figure 3C] Side view of the sleeve of the embodiment [Figure 3D] Cross-sectional view of the sleeve of the embodiment [Figure 4A] Diagram illustrating the function of the sleeve in the embodiment. [Figure 4B] Diagram illustrating the function of the sleeve in the embodiment. [Figure 4C] Diagram illustrating the function of the sleeve in the embodiment. [Figure 5A] A cross-sectional view showing the tip of another example of a writing instrument with the tip detached. [Figure 5B] A cross-sectional view showing the tip of another example of a writing instrument with the tip attached. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below with reference to the drawings. The following embodiments are merely examples of how the present invention can be implemented, and do not limit the present invention to their scope. In the following description, the tip end (the side from which the writing lead emerges during writing) of the writing instrument in the longitudinal direction (hereinafter referred to as the axial direction) will be referred to as the front end or tip end, and the opposite side will be referred to as the rear end.

[0010] Figures 1 and 2A and 2B show the writing instrument of this embodiment, respectively: Figure 1: a cross-sectional view of the cutting surface including the axis of the writing instrument; Figure 2A: a cross-sectional view showing the tip side of the writing instrument with the tip removed; and Figure 2B: a cross-sectional view showing the tip side of the writing instrument with the tip attached.

[0011] The writing instrument 1 of this embodiment is a writing instrument equipped with a feeding mechanism that grips the writing lead and advances it forward. The shaft 12 and, The tip 11 is screwed into the front side of the shaft cylinder 12, A click button 13 attached to the rear side of the shaft cylinder 12, A substantially cylindrical refill tube 18 for storing the refill L inside the shaft cylinder 12, A refill tank 19 communicating with the refill tube 18, A chuck 14 attached to the front side of the refill tube 18 for gripping and feeding the refill L forward, A chuck ring 15 fitted to the chuck 14, A chuck spring 16 for biasing the chuck 14 backward with respect to the chuck ring 15, A sleeve 17 for accommodating the chuck spring 16, is included.

[0012] The tip tool 11 is a member that supports the refill L on the front side of the writing instrument 1, has a tip pipe 111 at its front end through which the refill L can be inserted, and has a threaded portion 112 with a thread formed on the outer circumference for screwing with the shaft cylinder 12 at its rear end. Further, the tip tool 11 has a stepped portion 113 inside it that abuts against a sleeve 17 (expansion portion Y) to be described later (see Fig. 2A).

[0013] The shaft cylinder 12 is composed of three members: a front cylinder 121, a middle cylinder 122, and a rear cylinder 123, and houses a feeding mechanism for the refill L including the chuck 14 and the chuck spring 16, a refill tube 18 for storing the refill L, and a refill tank 19 inside it. On the inner peripheral wall surface of the front end portion (front cylinder 121 in this embodiment) of the shaft cylinder 12, a thread groove 124 for screwing with the threaded portion 112 of the tip tool 11 and a stepped portion 125 against which the rear end surface of a sleeve 17 (flange 173) to be described in detail later abuts are formed.

[0014] In this embodiment, a chuck 14 having chuck pieces whose front end portion is divided into three is assembled to the front end portion of a refill tube 18 formed in a substantially cylindrical shape. The refill tube 18 is assembled to the front end portion of the refill tank 19 so as to communicate with the refill tank 19. A click button 13 is assembled to the rear end side of the refill tank 19 so as to close the rear end openings of the refill tank 19 and the shaft cylinder 12. The writing lead tube 18 and the chuck 14 assembled to the writing lead tube 18 are biased backward by the chuck spring 16. Therefore, when the click action is not performed, the chuck 14 retracts and engages with the rear chuck ring 15 supported by the sleeve, thereby gripping the writing lead L. When the click button 13 is clicked (pushed forward), the chuck 14, which grips the writing lead L, moves forward and feeds the writing lead L forward. When the chuck ring 15, which is engaged with the chuck 14, moves forward, the chuck ring 15 comes into contact with the tip 11 and detaches from the chuck 14 to the rear. When the chuck ring 15 detaches from the chuck 14 to the rear, the chuck piece of the chuck 14 opens due to elasticity, and the writing lead L is released from the grip of the chuck 14 at the position it was fed out. When the click button 13 is released from the click operation, the chuck spring 16 causes the chuck 14, whose chuck piece has opened, to retract and re-engage with the chuck ring 15 at a position further rearward than the fed-out writing lead L, and the writing lead is gripped again.

[0015] The sleeve 17 is a substantially cylindrical member that houses the chuck spring 16 which operates as described above. Furthermore, as will be described in detail below, the sleeve 17 of this embodiment is configured to apply a biasing force to the end piece 11, thereby increasing the frictional force of the screw connection between the end piece 11 and the shaft cylinder 12. Figures 3A to 3D show the sleeve 17, with Figure 3A being a perspective view, Figure 3B a plan view seen from the front, Figure 3C a side view, and Figure 3D a cross-sectional view including the axis. Figures 4A to 4C are diagrams illustrating the function of the sleeve 17, with Figure 4A being an enlarged view of the front end portion of the sleeve 17, Figure 4B being an enlarged view of the area near the front end of the sleeve 17 with the sleeve 17 assembled and the tip 11 removed, and Figure 4C being an enlarged view of the area near the front end of the sleeve 17 with both the sleeve 17 and the tip 11 assembled. Sleeve 17 is The chuck ring 15 has an expanded portion Y that extends radially outward from its outer circumference, and an elastic portion 171 that deforms elastically in the axial direction, The relief portion 172 provides space for the elastic portion 171 to undergo elastic deformation, It has a flange 173 that abuts against the stepped portion 125 of the shaft cylinder 12.

[0016] The elastic portion 171 is configured to elastically deform and generate a biasing force in the axial direction when a compressive load is applied in the axial direction. The elastic portion 171 will be described in detail later. The relief portion 172 is a space formed for the elastic portion 171 to undergo elastic deformation, and is formed at the tip of the sleeve 17. As shown in Figure 3D, it has a tapered portion 1721 that tapers towards the front and a small-diameter portion 1722 that connects to the front of the tapered portion 1721. As shown in Figure 2B, the rear surface of the tapered portion 1721 is configured to contact the front end surface of the chuck spring 16 to lock the chuck spring 16.

[0017] As shown in Figure 4B, the elastic portion 171 has an expanded portion Y whose outer diameter is larger than the outer diameter of the chuck ring 15, and the expanded portion Y, which extends outward from the outer circumference of the chuck ring 15, comes into contact with the stepped portion 113 formed inside the tool tip 11 (see Figure 4C). Furthermore, the extension Y is configured to protrude forward of the rear end face of the chuck ring 15 when the tip 11 is not screwed into the shaft cylinder 12 (Figure 4B) (it protrudes by the amount indicated by X in Figure 4B).

[0018] The rear end surface of the flange 173 of the sleeve 17 abuts against the stepped portion 125 formed on the inner circumferential wall surface of the shaft cylinder 12, so that the sleeve 17 is assembled to a predetermined position relative to the shaft cylinder 12. This makes it possible to set the biasing force that the elastic portion 171 (expansion portion Y) applies to the end tool 11 when the sleeve 17 comes into contact with the end tool 11 to a predetermined value.

[0019] The sleeve 17 is assembled with the chuck 14, chuck ring 15, chuck spring 16, and writing lead tube 18 (and writing lead tank 19), and the assembly is inserted from the front of the barrel 12 until the flange 173 abuts against the stepped portion 125 (see Figure 2A). In this state, when the end fitting 11 is screwed onto the shaft cylinder 12 from the front, the stepped portion 113 formed inside the end fitting 11 comes into contact with the elastic portion 171 (expansion portion Y) of the sleeve 17. At this time, the initial contact between the end fitting 11 (stepped portion 113) and the sleeve 17 (expansion portion Y) is a line contact (contact occurs at the point that protrudes most far forward from the expansion portion Y, and in this embodiment, it is a circular line contact). Furthermore, as the tip 11 is screwed in, the elastic portion 171 is compressed, and the biasing force of the tip 11 increases as a reaction force to the compressive force that the tip 11 exerts on the elastic portion 171. This biasing force increases the frictional force of the screw connection between the tip 11 and the shaft 12, thereby preventing the tip 11 from falling out of the shaft 12. When the tip 11 is attached to the shaft 12 (screwed in to a predetermined position), the contact state between the tip 11 (stepped portion 113) and the sleeve 17 (elastic portion 171) changes from the aforementioned line contact to surface contact (see Figure 4C). The elastic portion 171 is configured to make line contact with the end tool 11 from its radially outwardly extended portion Y, and as it elastically deforms, the surface contact expands radially inward and outward. Therefore, a large rotational restraining moment for preventing loosening can be efficiently applied to the end tool 11, and the end tool 11 can be efficiently prevented from falling off.

[0020] The elastic portion 171 of the sleeve 17 in this embodiment is configured to have a cantilevered cross-sectional shape and has a relief portion 172 at its rear, allowing for large elastic deformation in the axial direction. Furthermore, the contact between the end piece 11 and the sleeve 17 is configured to transition from line contact to surface contact as the elastic portion 171 of the sleeve deforms elastically, allowing the elastic portion 171 of the sleeve to deform elastically more significantly. This enables the sleeve 17 to impart a large biasing force to the end piece 11 in the axial direction, thereby suitably increasing the frictional force of the screw engagement between the end piece 11 and the shaft cylinder 12.

[0021] As described above, according to the writing instrument 1 of this embodiment, the sleeve 17 provides a biasing force to the tip 11, and this biasing force increases the frictional force of the screw connection between the tip 11 and the barrel 12. Therefore, even in environments where the writing instrument is subjected to impacts relatively frequently, such as when used on a construction site, it is possible to reduce the likelihood of the screw fastening of the tip loosening due to such impacts.

[0022] In the above embodiment, a writing instrument 1 in which the elastic portion 171 is formed on the tip side of the sleeve 17 is illustrated. However, in other embodiments, the elastic portion may be formed at any position between the contact portion in which the sleeve abuts against the barrel (in the above embodiment, the flange 173 abutting against the stepped portion 125) and the front end portion in which the sleeve abuts against the tip (in the embodiment, the front end surface of the sleeve). Alternatively, multiple elastic portions may be formed at multiple positions in the axial direction. Figures 5A and 5B illustrate a writing instrument 1' in which the elastic portion 171' is formed at the front and rear ends of the sleeve 17', as an example of another embodiment. Note that components similar to those in the embodiments described above are referred to by the same reference numerals and their descriptions are omitted.

[0023] The writing instrument 1' shown in Figures 5A and 5B differs from the writing instrument 1 of the embodiment in the barrel 12' (tip barrel 121') and sleeve 17', but the other components are the same as in Embodiment 1. In writing instrument 1', the rear end of the sleeve 17' is configured to contact the stepped portion 125' of the barrel 12' (tip barrel 121'). One of the elastic portions 171' formed on the sleeve 17' is configured to be elastically deformable in the axial direction by forming a notch (hole) in a part of the circumferential direction of the rear of the cylindrical sleeve 17'. Furthermore, the tip surface of the other elastic portion 171' formed on the sleeve 17' is formed as an inclined surface (inclined surface with respect to the axis) where the outer circumference is located in front of the inner circumference. In this case as well, similar to the embodiment described above, the front end surface, which is an elastic portion formed on the sleeve 17', can undergo large elastic deformation, thereby imparting a large axial biasing force to the tip 11'. The elastic portion 171' at the tip of the sleeve 17' of the writing instrument 1' is configured to expand radially inward as it elastically deforms from line contact with the tip 11' from its outer circumference. Therefore, similar to the embodiment described above, a large rotational restraining moment for preventing loosening can be efficiently applied to the tip 11', and the tip 11' can be efficiently prevented from falling off. In this way, multiple elastic portions 171' may be formed by distributing them across multiple parts of the sleeve 17'.

[0024] According to writing instrument 1', similar to writing instrument 1 of the embodiment, the sleeve 17' provides a biasing force to the tip 11, and this biasing force increases the frictional force of the screw connection between the tip 11' and the barrel 12', thereby preventing the screw fastening of the tip from loosening.

[0025] In the embodiments described above, the basic form of the sleeve was exemplified as cylindrical (with a circular cross-sectional shape), but in other embodiments, for example, the cross-sectional shape of the sleeve may be polygonal. [Explanation of symbols]

[0026] 1...Writing implements 11...Tip 12...Shaft tube 14... Chuck 15...Chuckling 16... Chuck spring 17... Sleeves 171...Elastic part 172...Escape Club 18... Writing lead tube Y...extension part

Claims

1. The barrel and, A tip that is screwed onto the front side of the aforementioned shaft cylinder, Inside the barrel, there is a roughly cylindrical lead tube that houses the writing lead, A chuck is attached to the front side of the writing lead tube and grips the writing lead and feeds it forward, A chuck ring that engages with the aforementioned chuck, The chuck is biased rearward by a chuck spring relative to the chuck ring, A sleeve for housing the chuck spring, Includes, The sleeve has an elastic portion that deforms elastically in a direction along the shaft of the writing instrument, and when the tip is screwed into the barrel, the tip comes into contact with the sleeve, the elastic portion is compressed, and this compression imparts a biasing force to the tip, thereby increasing the frictional force of the screw connection between the tip and the barrel. The elastic portion of the sleeve has an expanded portion that extends outward beyond the outer circumference of the chuck ring. A writing instrument in which, when the tip is screwed into the barrel, the compression is performed when the tip comes into contact with the expansion portion.

2. The writing instrument according to claim 1, wherein, when the tip is not screwed into the barrel, the expansion portion protrudes forward of the rear end face of the chuck ring.

3. The writing instrument according to claim 1 or 2, wherein when the tip is screwed into the barrel, the contact between the tip and the sleeve transitions from line contact to surface contact.

4. A shaft cylinder and, A tip that is screwed onto the front side of the aforementioned shaft cylinder, Inside the barrel, there is a roughly cylindrical lead tube that houses the writing lead, A chuck is attached to the front side of the writing lead tube and grips the writing lead and feeds it forward, A chuck ring that engages with the aforementioned chuck, The chuck is biased rearward by a chuck spring relative to the chuck ring, A sleeve for housing the chuck spring, Includes, The sleeve has an elastic portion that deforms elastically in a direction along the shaft of the writing instrument, and when the tip is screwed into the barrel, the tip comes into contact with the sleeve, the elastic portion is compressed, and this compression imparts a biasing force to the tip, thereby increasing the frictional force of the screw connection between the tip and the barrel. A writing instrument in which, when the tip is screwed into the barrel, the contact between the tip and the sleeve transitions from line contact to surface contact.

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