Disappearance-style notebook
The retractable writing instrument uses a novel mechanism with cams and a rotor to prevent unintended contact and injury, ensuring safe and quiet operation by restricting rotor rotation during state changes.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-06-10
- Publication Date
- 2026-04-09
AI Technical Summary
Existing retractable writing instruments risk contamination or injury due to unintended contact with the writing part when the cap is fitted at an angle or accidentally touched during use.
A retractable writing instrument with a novel mechanism featuring a barrel, cap, rotor, and cams that cooperate to switch between writing and non-writing states, preventing unintended contact by restricting rotor rotation with the knock cam and outer cam.
Prevents contamination and injury by ensuring the writing part remains protected during cap insertion and removal, minimizing movement and noise, and maintaining a stable writing feel.
Smart Images
Figure 0007843187000001 
Figure 0007843187000002 
Figure 0007843187000003
Abstract
Description
Technical Field
[0004] , , , , , , , , , , , ,
[0005]
[0001] The present invention relates to a retractable writing instrument.
Background Art
[0002] There is known a so-called knock-type retractable writing instrument having an operation part at the rear end of a shaft cylinder, and by performing a knock operation for pressing the operation part forward against the biasing force of a spring disposed within the shaft cylinder, a refill containing ink, that is, a writing part which is the tip of the writing body, is switched to a writing state protruding from the tip of the shaft cylinder, and by a second knock operation or by operating a release part different from the operation part, the writing part is switched to a non-writing state where it is retracted into the shaft cylinder (for example, Patent Documents 1 and 2).
[0003] The retractable writing instrument described in Patent Document 1 has a cap that can be fitted to the front end of the shaft cylinder and functions as an operation part, mainly for preventing evaporation of ink from the writing part at the tip of the refill when not in use. In the retractable writing instrument described in Patent Document 1, when switching from the non-writing state to the writing state using it as an operation part, the cap is fitted to the rear end of the shaft cylinder and the knock operation is performed.
[0004] The retractable writing instrument described in Patent Document 2 has a cap that functions as an operation part for preventing the operation part from being unintentionally pressed forward and changing from the non-writing state to the writing state. The retractable writing instrument described in Patent Document 2 is configured such that the knock operation cannot be performed unless the cap is fitted to the rear end of the shaft cylinder.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0006] The retractable writing instruments described in Patent Documents 1 and 2 allow the cap to be removed from the rear end of the barrel and fitted onto the front end while the writing section is protruding from the barrel in a writing state. However, if the cap is fitted onto the front end of the barrel with its axis at an angle while writing, the inside of the cap may come into contact with the writing section and become stained with ink. Furthermore, when fitting the cap onto the front end of the barrel while writing, there is a risk of accidentally touching the writing section, staining one's hands with ink, or injuring oneself with the sharp tip of the writing section.
[0007] The present invention aims to provide a retractable writing instrument equipped with a novel retractable mechanism. This aims to prevent unintended contact of the writing part, thereby preventing contamination or injury. [Means for solving the problem]
[0008] According to one aspect of the present invention, a retractable writing instrument is provided, comprising a barrel, a cap having a knock cam and fitted to the rear end of the barrel, a rotor biased rearward within the barrel, and an outer cam provided on the inner surface of the barrel, wherein the knock cam and the outer cam are configured to cooperate with the rotor to rotate the rotor, and the writing instrument is capable of switching between a writing state in which the rotor is engaged with the outer cam and a non-writing state in which the rotor is disengaged from the outer cam, characterized in that, as the rear end of the barrel is inserted into the cap, the knock cam presses against the rotor, causing the rotor to advance and rotate, and the rotation of the rotor is restricted by circumferential contact with the knock cam, causing the rotor to engage with the outer cam and enter the writing state.
[0009] The outer cam has a plurality of first cam portions arranged circumferentially on the inner surface of the shaft cylinder and having a first cam surface on its front end face, and a plurality of guide grooves extending in the front-rear direction defined between the plurality of first cam portions, the knock cam has a second cam portion configured to be movable in the front-rear direction within the guide grooves and having a second cam surface on its front end face, the rotor has a third cam portion configured to be movable in the front-rear direction within the guide grooves and having a cam receiving surface on its rear end face that cooperates with the first cam surface and the second cam surface, and as the rear end of the shaft cylinder is inserted into the cap, the second cam surface presses against the cam receiving surface to advance and rotate the rotor, and the side surface of the third cam portion of the rotor comes into contact with the side surface of the second cam portion of the knock cam, thereby restricting the rotation of the rotor. The first cam portion may have a fourth cam surface on its rear end face, and the second cam surface and the fourth cam surface may cooperate as the rear end of the barrel is inserted into the cap, causing the cap to rotate so that the second cam portion enters the guide groove. In the writing state, the restriction on the rotation of the rotor by the knock cam may be released when the cap is removed from the rear end of the barrel, allowing the rotor to rotate and disengage from the outer cam, resulting in a non-writing state. A locking portion may be formed on the outer surface of the barrel, and a locked portion may be formed on the inner surface of the cap, and the rotor may be configured to contact the knock cam in the circumferential direction when the locking portion and the locked portion are engaged as the rear end of the barrel is inserted into the cap. The rear end of the rotor may be located forward of the rear end of the barrel. [Effects of the Invention]
[0010] According to aspects of the present invention, a common effect is to provide a retractable writing instrument equipped with a novel retractable mechanism. This makes it possible to prevent unintended contact of the writing part, thereby preventing contamination or injury. [Brief explanation of the drawing]
[0011] [Figure 1]Figure 1 is a perspective view of the retractable writing instrument according to the first embodiment in a non-writing state. [Figure 2] Figure 2 is a perspective view of the writing state of the retractable writing instrument shown in Figure 1. [Figure 3] Figure 3 is a longitudinal cross-sectional view of the retractable writing instrument shown in Figure 1 in its non-writing state. [Figure 4] Figure 4 is a longitudinal cross-sectional view of the retractable writing instrument shown in Figure 1 in the writing state. [Figure 5] Figure 5 is a longitudinal cross-sectional view of the rear end of the barrel of the retractable writing instrument shown in Figure 1. [Figure 6] Figure 6 is a perspective view of the knock cam of the retractable writing instrument shown in Figure 1. [Figure 7] Figure 7 is a perspective view of the rotor of the retractable writing instrument shown in Figure 1. [Figure 8] Figure 8 is a perspective view of the retractable mechanism of the writing instrument shown in Figure 1. [Figure 9] Figure 9 is a schematic diagram of the retractable mechanism that shows the switching from the non-writing state to the writing state of the retractable writing instrument shown in Figure 1. [Figure 10] Figure 10 is a schematic diagram of the retractable mechanism that shows the switching between the writing state and the non-writing state of the retractable writing instrument shown in Figure 1. [Figure 11] Figure 11 is a longitudinal cross-sectional view of the retractable writing instrument according to the second embodiment in a non-writing state. [Figure 12] Figure 12 is a longitudinal cross-sectional view of the retractable writing instrument shown in Figure 11 in the writing state. [Figure 13] Figure 13 is a longitudinal cross-sectional view of the rear end of the barrel of the retractable writing instrument shown in Figure 11. [Figure 14] Figure 14 is a perspective view of the knock cam of the retractable writing instrument shown in Figure 11. [Figure 15] Figure 15 is a perspective view of the rotor of the retractable writing instrument shown in Figure 11. [Figure 16] Figure 16 is a perspective view of the retractable mechanism of the writing instrument shown in Figure 11. [Figure 17] Figure 17 is a schematic diagram of the retractable mechanism that shows the switching from the non-writing state to the writing state of the retractable writing instrument shown in Figure 11. [Figure 18]FIG. 18 is a schematic diagram of the retracting mechanism showing the switching of the retractable writing instrument from the writing state to the non-writing state in FIG. 11. [Figure 19] FIG. 19 is a longitudinal sectional view of the retractable writing instrument in the non-writing state according to the third embodiment. [Figure 20] FIG. 20 is a longitudinal sectional view of the retractable writing instrument in FIG. 19 with the cap disposed at the rear end portion of the barrel. [Figure 21] FIG. 21 is a longitudinal sectional view of the retractable writing instrument in FIG. 19 in the writing state. [Figure 22] FIG. 22 is a longitudinal sectional view of the rear end portion of the barrel of the retractable writing instrument in FIG. 19. [Figure 23] FIG. 23 is a perspective view of the knock cam of the retractable writing instrument in FIG. 19. [Figure 24] FIG. 24 is a perspective view of the rotor of the retractable writing instrument in FIG. 19. [Figure 25] FIG. 25 is a perspective view of the retracting mechanism of the retractable writing instrument in FIG. 19 in the writing state. [Figure 26] FIG. 26 is a schematic diagram of the retracting mechanism showing the switching of the retractable writing instrument in FIG. 19 from the non-writing state to the writing state. [Figure 27] FIG. 27 is a schematic diagram of the retracting mechanism showing the switching of the retractable writing instrument in FIG. 19 from the writing state to the non-writing state. MODE FOR CARRYING OUT THE INVENTION
[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, corresponding components are denoted by common reference numerals.
[0013] FIG. 1 is a perspective view of the retractable writing instrument 1 in the non-writing state according to the first embodiment, FIG. 2 is a perspective view of the retractable writing instrument 1 in FIG. 1 in the writing state, FIG. 3 is a longitudinal sectional view of the retractable writing instrument 1 in FIG. 1 in the non-writing state, and FIG. 4 is a longitudinal sectional view of the retractable writing instrument 1 in FIG. 1 in the writing state.
[0014] The retractable writing instrument 1 comprises a barrel 3 formed in a cylindrical shape and equipped with a tip member 2, a refill 5 which is a writing body disposed inside the barrel 3 and equipped with a writing section 4 at one end, a spring 6 which biases the refill 5 backward, and a retractable mechanism 10 located at the rear end of the barrel 3. The refill 5 is, for example, a ballpoint pen refill. The retractable mechanism 10 comprises an outer cam 20, a knock cam 30, and a rotor 40. The tip member 2 located at the front end of the barrel 3 is tapered toward the front and has a through hole formed therein for the writing section 4 of the refill 5 to protrude.
[0015] In this specification, in the axial direction of a retractable writing instrument, the side with the writing section is defined as the "front" side, and the side opposite the writing section is defined as the "rear" side. In the retractable writing instrument 1, the refill 5 moves in the front-rear direction within the barrel 3 by the retractable mechanism 10. At this time, the state in which the writing section 4 is retracted into the barrel 3 is referred to as the non-writing state (Figures 1 and 3), and the state in which the writing section 4 protrudes from the barrel 3 is referred to as the writing state (Figures 2 and 4).
[0016] An operating part 7 is provided at the rear end of the retractable writing instrument 1, that is, at the rear end of the barrel 3. The operating part 7 has a knock cam 30. The retractable writing instrument 1 is a so-called knock-type writing instrument that enters writing mode by a knock operation that pushes the operating part 7 forward. In particular, as shown in Figure 2, the barrel 3 has a flat part 3a that extends forward from the rear end, and the flat part 3a has a notch 3b that extends forward from the rear end. The operating part 7 has a clip 8 that extends forward along the side surface of the barrel 3. The clip 8 is connected to the operating part 7 via the notch 3b.
[0017] Figure 5 is a longitudinal cross-sectional view of the rear end of the barrel 3 of the retractable writing instrument 1 shown in Figure 1. In Figure 5, the lower part is the front of the retractable writing instrument 1. An outer cam 20, which constitutes part of the retractable mechanism 10, is provided on the inner surface of the rear end of the barrel 3. The outer cam 20 has four protruding first cam portions 21 arranged at equal intervals along the circumferential direction on the inner surface of the barrel 3. The first cam portions 21 extend in the front-rear direction and their rear ends are connected to each other in an annular manner. A first cam surface 22 is provided on the front end surface of the first cam portion 21. The first cam surface 22 is a surface that is inclined along the circumferential direction. Four guide grooves 23 extending in the front-rear direction are defined between the four first cam portions 21. Therefore, the outer cam 20 has four first cam portions 21 and four guide grooves 23. A regulating surface 24 is provided at the portion where the first cam portions 21 are connected at the rear end of the guide groove 23.
[0018] Figure 6 is a perspective view of the knock cam 30 of the retractable writing instrument 1 shown in Figure 1. In Figure 6, the lower part is the front of the retractable writing instrument 1. The knock cam 30 is integrally provided with the operating section 7. The rear part of the operating section 7 is a cylindrical member, and a mounting hole 7a for connecting the clip 8 is provided on its side. The knock cam 30, located at the front of the operating section 7, has four protruding second cam sections 31 that are arranged at equal intervals along the circumferential direction and extend in the front-rear direction. Each of the second cam sections 31 is movably positioned in the front-rear direction within the guide groove 23 of the outer cam 20. A second cam surface 32 is provided on the front end surface of the second cam section 31. The second cam surface 32 is a surface that is inclined along the circumferential direction, similar to the first cam surface 22 of the outer cam 20. A first contact surface 33 is provided on the circumferential side surface of the second cam section 31. A locking surface 34 is provided on the rear end surface of the second cam section 31.
[0019] Figure 7 is a perspective view of the rotor 40 of the retractable writing instrument 1 shown in Figure 1. In Figure 7, the lower part is the front of the retractable writing instrument 1. The rotor 40 has four projection-shaped third cam portions 41 that are arranged at equal intervals along the circumferential direction and extend in the front-rear direction. The four third cam portions 41 constitute an inner cam. Each of the third cam portions 41 is positioned to be movable in the front-rear direction within the guide groove 23 of the outer cam 20. A cam receiving surface 42 is provided on the rear end surface of the third cam portion 41. The cam receiving surface 42 is a surface that is inclined along the circumferential direction, facing the first cam surface 22 of the outer cam 20 and the second cam surface 32 of the knock cam 30. The rear end surface of the refill 5, which is biased by the spring 6, abuts against the front end surface of the rotor 40. Therefore, the rotor 40 is always biased rearward via the refill 5 by the spring 6. A second contact surface 43 is provided on the circumferential side surface of the third cam portion 41.
[0020] Figure 8 is a perspective view of the retractable mechanism 10 of the retractable writing instrument 1 in the writing state shown in Figure 1. In Figure 8, the outer cam 20 is omitted. In the writing state, as will be described later with reference to Figure 9, the third cam portion 41 of the rotor 40 engages with the first cam portion 21 of the outer cam 20. At this time, the rotation of the rotor 40 is restricted by the rotor 40 contacting the knock cam 30 in the circumferential direction, specifically by the second contact surface 43 contacting the first contact surface 33, thereby maintaining the writing state.
[0021] Figure 9 is a schematic diagram of the retractable mechanism 10 that shows the switching of the retractable writing instrument 1 from the non-writing state to the writing state in Figure 1. Specifically, Figure 9 is a schematic diagram showing the positional relationship between the outer cam 20, the knock cam 30, and the rotor 40, showing the positions of the second cam portion 31 of the knock cam 30 and the third cam portion 41 of the rotor 40 relative to the outer cam 20 when it is extended in the circumferential direction. In the figure, the bottom is the front of the retractable writing instrument 1, and the top is the rear of the retractable writing instrument 1. The rotor 40 is given rotational force by the cooperation of the first cam surface 22 of the outer cam 20 or the second cam surface 32 of the knock cam 30 and the cam receiving surface 42 of the rotor 40, and rotates in one direction around the central axis. Therefore, the rotor 40 moves from right to left in Figure 9.
[0022] Figure 9(A) is a schematic diagram of the retractable mechanism 10 of the retractable writing instrument 1 in the non-writing state. In the non-writing state, the second cam portion 31 of the knock cam 30 and the third cam portion 41 of the rotor 40, which is biased rearward by the spring 6 via the refill 5, are positioned rearward within the guide groove 23 between the outer cams 20. The retraction of the knock cam 30 and the rotor 40 is restricted by the locking surface 34 of the knock cam 30 engaging with the regulating surface 24 of the outer cam 20. Therefore, in this state, the writing portion 4 is retracted into the barrel 3.
[0023] From the state shown in Figure 9(A), the knock cam 30 and rotor 40 are advanced by performing a knock operation that presses the operating part 7 against the biasing force of the spring 6. At this time, the second cam portion 31 of the knock cam 30 and the third cam portion 41 of the rotor 40 advance within the guide groove 23. The knock cam 30 and rotor 40 are subjected to circumferential force components in opposite directions via the inclined surfaces of the second cam surface 32 and the cam receiving surface 42, but their circumferential movement, i.e., rotation, is restricted by the contact between the second cam portion 31 of the knock cam 30 or the third cam portion 41 of the rotor 40 and the side surface of the first cam portion 21 of the outer cam 20.
[0024] As the knock cam 30 and rotor 40 move further forward, the rear end of the third cam portion 41 of the rotor 40 crosses the front end of the outer cam 20, i.e., the first cam portion 21, in the front-rear direction, causing the first cam surface 22 and the second cam surface 32 to coincide, and the restriction on the rotation of the rotor 40 by the outer cam 20 is released (Figure 9(B)). As a result, the rotor 40, which is biased to the rear, receives circumferential force components from the second cam surface 32 and the first cam surface 22, and the rotor 40 rotates around its central axis as the cam receiving surface 42 slides sequentially over the second cam surface 32 and the first cam surface 22 (Figure 9(C)).
[0025] The third cam portion 41 of the rotor 40 moves along the second cam surface 32 of the knock cam 30 and the first cam surface 22 of the outer cam 20 in that order until it contacts the side surface of the second cam portion 31 of the knock cam 30. That is, the rotation of the rotor 40 is stopped and restricted when the second contact surface 43 contacts the first contact surface 33 of the knock cam 30. At this time, the retraction of the rotor 40, which is biased to the rear, is restricted by the engagement of the third cam portion 41 with the first cam portion 21 (Figure 9(D)). In short, by the rotor 40 engaging with the outer cam 20, the writing portion 4 of the refill 5, which is positioned in front of the rotor 40, is kept protruding from the barrel 3, and the retractable writing instrument 1 is in the writing state.
[0026] Although the spring 6 biases the rotor 40 backward via the refill 5, in the writing state, this biasing force is supported only by the outer cam 20, as shown in Figure 9(D). Therefore, in the writing state, no force acts to retract the knock cam 30, i.e., the operating part 7.
[0027] Figure 10 is a schematic diagram of the retractable mechanism 10 that shows the switching from the writing state to the non-writing state of the retractable writing instrument 1 shown in Figure 1. In Figure 10, the positional relationship between the outer cam 20, the knock cam 30, and the rotor 40 is shown in the same way as in Figure 9.
[0028] Figure 10(A) is a schematic diagram of the retractable mechanism 10 of the retractable writing instrument 1 in the writing state, and is the same schematic diagram as Figure 9(D). From the state in Figure 10(A), the operating part 7, and thus the knock cam 30, is retracted by sliding the clip 8 backward, for example (Figure 10(B)). When the knock cam 30 retracts, the front end of the second cam portion 31 of the knock cam 30 passes the rear end of the rotor 40, i.e., the third cam portion 41, in the front-rear direction, and the first cam surface 22 and the second cam surface 32 coincide, and the restriction of the rotation of the rotor 40 by the knock cam 30 is released. As a result, the rotor 40, which is biased backward, receives a circumferential component force from the first cam surface 22, and the rotor 40 rotates further around the central axis as the cam receiving surface 42 slides sequentially over the first cam surface 22 and the second cam surface 32 (Figure 10(C)).
[0029] The third cam portion 41 of the rotor 40 moves along the first cam surface 22 of the outer cam 20 and the second cam surface 32 of the knock cam 30 in that order, until it contacts the side surface of the first cam portion 21 of the outer cam 20. As a result, the rotation of the rotor 40 is stopped and restricted (Figure 10(D)). In this state, since the rotor 40 is disengaged from the outer cam 20, the rotor 40 and the knock cam 30 retract within the guide groove 23 due to the biasing force of the spring 6. The retraction of the knock cam 30 and the rotor 40 is restricted by the locking surface 34 of the knock cam 30 engaging with the restricting surface 24 of the outer cam 20 (Figure 10(E)). In short, by disengaging the rotor 40 from the outer cam 20, the writing portion 4 of the refill 5, which is positioned in front of the rotor 40, remains retracted into the barrel 3, and the retractable writing instrument 1 is in a non-writing state. Note that Figure 10(E) is the same schematic diagram as Figure 9(A).
[0030] According to the first embodiment described above, a retractable writing instrument 1 equipped with a novel retractable mechanism 10 can be provided. This makes it possible to prevent rattling of the operating part 7 and prevent impact to the refill 5 with a simpler structure.
[0031] In other words, as described above with reference to Figure 9, in the writing state, the rotor 40, which is biased to the rear, receives a circumferential component force that presses against the knock cam 30 via the first cam surface 22 of the outer cam 20 and the inclined surface of the cam receiving surface 42. Therefore, in the writing state, the knock cam 30 is held between the first cam portion 21 of the outer cam 20 and the third cam portion 41 of the rotor 40. Consequently, the operating section 7 does not rattle due to repeated contact between the writing surface and the writing section 4 caused by the writing motion, preventing the generation of noise and vibration caused by rattle, and a decrease in writing feel. Furthermore, additional configurations to prevent rattle of the operating section 7, such as the addition of a spring to constantly bias the operating section 7 to the rear, are unnecessary, and since it is composed of a minimum number of parts, the retractable mechanism can be realized with a very simple structure.
[0032] In typical retractable writing instruments, the knocking operation to switch from writing to non-writing mode required advancing the rotor further than the writing position to disengage it from the outer cam. As a result, the amount of movement of the spring-driven refill from the advanced position to the non-writing position was large. In addition, the clicking or impact sound occurred twice: the first time the rotor moved forward due to the knocking operation, and the second time the rotor retracted to enter the non-writing state.
[0033] On the other hand, in the first embodiment described above, since there is no need to advance the rotor 40 and, consequently the refill 5, by the knocking operation when switching from the writing state to the non-writing state, the amount of movement of the refill 5 can be minimized. This prevents impact on the refill 5, prevents air from entering the refill 5 due to impact, and prevents the occurrence of writing defects. In addition, since a click sound or impact sound is generated only when the rotor 40 retracts and enters the non-writing state, it is possible to switch between the writing state and the non-writing state quietly.
[0034] In the retractable writing instrument 1 according to the first embodiment described above, the operating part 7 is provided so as to protrude from the rear end of the barrel 3, but the operating part may also be provided on the side surface of the barrel, i.e., the outer circumferential surface. Also, although the retractable writing instrument 1 had a clip 8, it does not have to have a clip 8.
[0035] Figure 11 is a longitudinal cross-sectional view of the retractable writing instrument 100 in a non-writing state according to the second embodiment, and Figure 12 is a longitudinal cross-sectional view of the retractable writing instrument 10 of Figure 11 in a writing state.
[0036] The retractable writing instrument 100 comprises a barrel 103 formed in a cylindrical shape and equipped with a tip member 2, a refill 5 which is a writing body disposed inside the barrel 103 and equipped with a writing section 4 at one end, a spring 6 which biases the refill 5 backward, and a retractable mechanism 110 located at the rear end of the barrel 103. The retractable mechanism 110 comprises an outer cam 120, a knock cam 130, and a rotor 140. The tip member 2 located at the front end of the barrel 103 is tapered toward the front and has a through hole formed therein for the writing section 4 of the refill 5 to protrude.
[0037] In the retractable writing instrument 100, the refill 5 moves back and forth within the barrel 103 by the retractable mechanism 110. At this time, the state in which the writing part 4 is retracted into the barrel 103 is called the non-writing state (Figure 11), and the state in which the writing part 4 protrudes from the barrel 103 is called the writing state (Figure 12).
[0038] An operating part 107 is provided at the rear end of the retractable writing instrument 100, that is, at the rear end of the barrel 103. The operating part 107 has a knock cam 130. The retractable writing instrument 100 is a so-called knock-type writing instrument that enters writing mode by a knock operation that pushes the operating part 107 forward. The operating part 107 has a cylindrical cover member 108 that covers the operating part 107 along its length. The cover member 108 is integrally connected to the operating part 107.
[0039] Figure 13 is a longitudinal cross-sectional view of the rear end of the barrel 103 of the retractable writing instrument 100 shown in Figure 11. In Figure 13, the lower part is the front of the retractable writing instrument 100. An outer cam 120, which constitutes part of the retractable mechanism 110, is provided on the inner surface of the rear end of the barrel 103. The outer cam 120 has four protruding first cam portions 121 arranged at equal intervals along the circumferential direction on the inner surface of the barrel 103. The first cam portions 121 extend in the front-rear direction and their rear ends are connected to each other in an annular manner. A first cam surface 122 is provided on the front end surface of the first cam portion 121. The first cam surface 122 is a surface that is inclined along the circumferential direction. Four guide grooves 123 extending in the front-rear direction are defined between the four first cam portions 121. Therefore, the outer cam 120 has four first cam portions 121 and four guide grooves 123. A regulating surface 124 is provided at the rear end of the guide groove 123 where the first cam portion 121 is connected.
[0040] Furthermore, the first cam surface 122 of the outer cam 120 of the retractable writing instrument 100 differs from the first cam surface 22 of the outer cam 20 of the retractable writing instrument 1 according to the first embodiment in that, although it is a surface with the same inclination along the circumferential direction, it is inclined in the opposite direction.
[0041] A through hole 103a is formed in the rear end surface of the shaft cylinder 103 so that the operating part 107 can be inserted. A guide portion 103b is formed on the outer circumferential surface of the rear end of the shaft cylinder 103, having an outer diameter slightly smaller than the inner diameter of the cover member 108. The forward and backward movement of the cover member 108, and by extension the operating part 107, is guided by the guide portion 103b. A stepped portion 103c facing rear is formed in the front end portion of the guide portion 103b. The forward movement of the cover member 108, and by extension the operating part 107, is restricted by the front end surface of the cover member 108 contacting the stepped portion 103c.
[0042] Figure 14 is a perspective view of the knock cam 130 of the retractable writing instrument 100 shown in Figure 11. In Figure 14, the lower part is the front of the retractable writing instrument 100. The knock cam 130 is integrally provided with the operating part 107. The operating part 107 is a cylindrical member. The knock cam 130, located at the front of the operating part 107, has four protruding second cam portions 131 that are arranged at equal intervals along the circumferential direction and extend in the front-rear direction. Each of the second cam portions 131 is arranged to be movable in the front-rear direction within the guide groove 123 of the outer cam 120. A second cam surface 132 is provided on the front end surface of the second cam portion 131. The second cam surface 132 differs from the first cam surface 122 of the outer cam 120 in that it has the same inclination along the circumferential direction, but is inclined in the opposite direction. A first contact surface 133 is provided on the circumferential side surface of the second cam portion 131. A locking surface 134 is provided on the rear end surface of the second cam portion 131.
[0043] Furthermore, the first contact surface 133 of the knock cam 130 of the retractable writing instrument 100 differs from the first contact surface 33 of the knock cam 30 of the retractable writing instrument 1 according to the first embodiment in that it is the side surface opposite to the corresponding second cam portion 131 in the circumferential direction.
[0044] Figure 15 is a perspective view of the rotor 140 of the retractable writing instrument 100 shown in Figure 11. In Figure 15, the lower part is the front of the retractable writing instrument 100. The rotor 140 has four projection-shaped third cam portions 141 that are arranged at equal intervals along the circumferential direction and extend in the front-rear direction. The four third cam portions 141 constitute an inner cam. Each of the third cam portions 141 is positioned to be movable in the front-rear direction within the guide groove 123 of the outer cam 120. A cam receiving surface 142 is provided on the rear end face of the third cam portion 141. Each of the cam receiving surfaces 142 is formed in a V-shape and has a first cam receiving surface 144 and a second cam receiving surface 145. The first cam receiving surface 144 and the second cam receiving surface 145 are surfaces that are inclined in opposite directions along the circumferential direction, and the third cam portion 141 is formed symmetrically. The first cam receiving surface 144 is a surface similarly inclined in the circumferential direction so as to face the second cam surface 132 of the knock cam 130, and the second cam receiving surface 145 is a surface similarly inclined along the circumferential direction so as to face the first cam surface 122 of the outer cam 120. The rear end surface of the refill 5, biased by the spring 6, abuts against the front end surface of the rotor 140. Therefore, the rotor 140 is always biased rearward via the refill 5 by the spring 6. A second contact surface 143 is provided on the circumferential side surface of the third cam portion 141.
[0045] Furthermore, the second contact surface 143 of the rotor 140 of the retractable writing instrument 100 differs from the second contact surface 43 of the rotor 40 of the retractable writing instrument 1 according to the first embodiment in that it is the side surface opposite to the corresponding third cam portion 141 in the circumferential direction.
[0046] Figure 16 is a perspective view of the retractable mechanism 110 of the retractable writing instrument 100 in the writing state shown in Figure 11. In the writing state, as will be described later with reference to Figure 17, the third cam portion 141 of the rotor 140 engages with the first cam portion 121 of the outer cam 120. At this time, the rotation of the rotor 140 is restricted by the rotor 140 contacting the knock cam 130 in the circumferential direction, specifically by the second contact surface 143 contacting the first contact surface 133, thereby maintaining the writing state.
[0047] Figure 17 is a schematic diagram of the retractable mechanism that shows the switching from the non-writing state to the writing state of the retractable writing instrument 100 shown in Figure 11. Specifically, Figure 17 is a schematic diagram showing the positional relationship between the outer cam 120, the knock cam 130, and the rotor 140, showing the positions of the second cam portion 131 of the knock cam 130 and the third cam portion 141 of the rotor 140 with respect to the outer cam 120 when it is unfolded in the circumferential direction. In the figure, the bottom is the front of the retractable writing instrument 100, and the top is the rear of the retractable writing instrument 100. The rotor 140 is given rotational force by the cooperation of the first cam surface 122 of the outer cam 120 or the second cam surface 132 of the knock cam 130 and the cam receiving surface 142 of the rotor 140, and rotates in one direction or the other about the central axis within a predetermined angular range.
[0048] Figure 17(A) is a schematic diagram of the retractable mechanism 110 of the retractable writing instrument 100 in the non-writing state. In the non-writing state, the second cam portion 131 of the knock cam 130 and the third cam portion 141 of the rotor 140, which is biased rearward by the spring 6 via the refill 5, are positioned rearward within the guide groove 123 between the outer cams 120. The retraction of the knock cam 130 and the rotor 140 is restricted by the locking surface 134 of the knock cam 130 engaging with the regulating surface 124 of the outer cam 120. Therefore, in this state, the writing section 4 is retracted into the barrel 103.
[0049] From the state shown in Figure 17(A), the knock cam 130 and rotor 140 are advanced by performing a knock operation that presses the operating part 107 against the biasing force of the spring 6. At this time, the second cam portion 131 of the knock cam 130 and the third cam portion 141 of the rotor 140 advance within the guide groove 123. The knock cam 130 and rotor 140 are subjected to circumferential force components in opposite directions via the inclined surfaces of the second cam surface 132 and the cam receiving surface 142, specifically the inclined surfaces of the second cam surface 132 and the first cam receiving surface 144. However, the circumferential movement, i.e., rotation, of the knock cam 130 and rotor 140 is restricted by the contact between the second cam portion 131 of the knock cam 130 or the third cam portion 141 of the rotor 140 and the side surface of the first cam portion 121 of the outer cam 120.
[0050] As the knock cam 130 and rotor 140 move further forward, the rear end of the third cam portion 141 of the rotor 140 passes the front end of the outer cam 120, i.e., the first cam portion 121, in the front-rear direction, and the restriction on the rotation of the rotor 140 by the outer cam 120 is released (Figure 17(B)). As a result, the rotor 140, which is biased to the rear, receives a circumferential component force from the second cam surface 132, and the cam receiving surface 142, specifically the first cam receiving surface 144, slides along the second cam surface 132, causing the rotor 140 to rotate in one direction, which is the first direction, around the central axis (Figure 17(C)). The first direction is the direction from right to left in the figure.
[0051] When the rotor 140 rotates until the third cam portion 141 of the rotor 140 passes the second cam surface 132 of the knock cam 130, the front end of the second cam portion 131 of the knock cam 130 moves forward in the front-rear direction, passing over the rear end of the third cam portion 141 of the rotor 140. At this time, the cam receiving surface 142 of the rotor 140, specifically the second cam receiving surface 145, comes into contact with the first cam surface 122 of the outer cam 120. Next, due to the biasing force of the spring 6, the rotor 140 receives a circumferential component force through the inclined surfaces of the first cam surface 122 and the second cam receiving surface 145, and rotates in the opposite direction to the first direction described above, i.e., the second direction. The second direction is the direction from left to right in the figure.
[0052] The rotation of the rotor 140 is stopped and restricted when the second contact surface 143 comes into contact with the first contact surface 133 of the knock cam 130. At this time, the retraction of the rotor 140, which is biased to the rear, is restricted when the third cam portion 141 engages with the first cam portion 121 (Figure 17(D)). In short, the rotor 140 engages with the outer cam 120, maintaining the state in which the writing portion 4 of the refill 5, which is positioned in front of the rotor 140, protrudes from the barrel 103, and the retractable writing instrument 100 is in the writing state.
[0053] Although the spring 6 biases the rotor 140 backward via the refill 5, in the writing state, this biasing force is supported only by the outer cam 120, as shown in Figure 17(D). Therefore, in the writing state, no force acts to retract the knock cam 130, i.e., the operating part 107.
[0054] Figure 18 is a schematic diagram of the retractable mechanism 110 that shows the switching from the writing state to the non-writing state of the retractable writing instrument 100 shown in Figure 11. In Figure 18, the positional relationship between the outer cam 120, the knock cam 130, and the rotor 140 is shown in the same way as in Figure 17.
[0055] Figure 18(A) is a schematic diagram of the retractable mechanism 110 of the retractable writing instrument 100 in the writing state, and is the same schematic diagram as Figure 17(D). From the state in Figure 18(A), the operating part 107 is pulled backward by, for example, pinching the outer circumference of the operating part 107, thereby retracting the operating part 107 and, consequently, the knock cam 130. When the knock cam 130 retracts, the front end of the second cam portion 131 of the knock cam 130 passes the rear end of the rotor 140, i.e., the third cam portion 141, in the front-rear direction, and the restriction on the rotation of the rotor 140 by the knock cam 130 is released. As a result, the rotor 140, which is biased backward, receives a circumferential component force from the first cam surface 122, and the cam receiving surface 142, specifically the second cam receiving surface 145, slides along the first cam surface 122, causing the rotor 140 to rotate in the second direction around the central axis. The rotation of the rotor 140 is restricted by the contact between the first cam receiving surface 144 and the second cam surface 132 of the knock cam 130 (Figure 18(B)).
[0056] As the knock cam 130 retracts further, the third cam portion 141 of the rotor 140 moves along the first cam surface 122 of the outer cam 120 until it contacts the side surface of the first cam portion 121 of the outer cam 120. This stops and restricts the rotation of the rotor 140 (Figure 18(C)). In this state, since the rotor 140 is disengaged from the outer cam 120, the rotor 140 and the knock cam 130 retract within the guide groove 123 due to the biasing force of the spring 6. The retraction of the knock cam 130 and the rotor 140 is restricted by the locking surface 134 of the knock cam 130 engaging with the restricting surface 124 of the outer cam 120 (Figure 18(E)). In short, by disengaging the rotor 140 from the outer cam 120, the writing section 4 of the refill 5, which is positioned in front of the rotor 140, remains retracted into the barrel 103, and the retractable writing instrument 100 is in a non-writing state. Note that Figure 18(E) is the same schematic diagram as Figure 17(A).
[0057] The retractable writing instrument 100 according to the second embodiment described above has the effect of making the knocking operation quieter, in addition to the effects described above for the retractable writing instrument 1 according to the first embodiment. That is, in the retractable writing instrument 100, the rotor 140 does not rotate in one direction around the central axis, but rotates in one direction or the other within a predetermined angular range, so the angle of movement in a single knocking operation is also smaller. As a result, the sliding noise between the rotor 140 and the outer cam 120 or knock cam 130 is reduced.
[0058] The configuration of the V-shaped cam receiving surface 142 of the rotor 140 of the retractable writing instrument 100, and furthermore, the configuration of the corresponding outer cam 120 and knock cam 130, are applicable to the retractable writing instrument 1 according to the first embodiment described above and the retractable writing instrument 200 according to the second embodiment described later.
[0059] Figure 19 is a vertical cross-sectional view of the retractable writing instrument 200 according to the third embodiment in a non-writing state, Figure 20 is a vertical cross-sectional view of the retractable writing instrument 200 of Figure 19 with the cap 209 positioned at the rear end of the barrel 203, and Figure 21 is a vertical cross-sectional view of the retractable writing instrument 200 of Figure 19 in a writing state.
[0060] The retractable writing instrument 200 comprises a barrel 203 formed in a cylindrical shape and equipped with a tip member 2, a refill 5 which is a writing body disposed inside the barrel 203 and equipped with a writing section 4 at one end, a spring 6 which biases the refill 5 backward, and a retractable mechanism 210 located at the rear end of the barrel 203. The retractable mechanism 210 comprises an outer cam 220, a knock cam 230, and a rotor 240. The tip member 2 located at the front end of the barrel 203 is tapered toward the front and has a through hole formed therein for the writing section 4 of the refill 5 to protrude.
[0061] In the retractable writing instrument 200, the refill 5 moves back and forth within the barrel 203 by the retractable mechanism 210. At this time, the state in which the writing part 4 is retracted into the barrel 203 is called the non-writing state (Figure 19), and the state in which the writing part 4 protrudes from the barrel 203 is called the writing state (Figure 21).
[0062] A cap 209 can be fitted to the front and rear ends of the retractable writing instrument 200, i.e., the front and rear ends of the barrel 203. In this specification, the open end of the cap 209 is defined as the "front" side and the closed end is defined as the "rear" side in the axial direction. The cap 209 has a knock cam 230. As described later, the retractable writing instrument 200 can be switched from a non-writing state to a writing state by fitting the cap 209 to the rear end of the barrel 203, and can be switched from a writing state to a non-writing state by removing the cap 209 from the rear end of the barrel 203.
[0063] A through hole 203a is formed in the rear end face of the shaft cylinder 203. A first locking portion 203b is formed on the front outer surface of the shaft cylinder 203, and a second locking portion 203c is formed on the rear outer surface of the shaft cylinder 203. On the other hand, a locked portion 209a is formed on the inner surface of the cap 209. The first locking portion 203b and the second locking portion 203c are annular protrusions formed on the outer surface of the shaft cylinder 203. The locked portion 209a is an annular recess formed on the inner surface of the cap 209 and is formed complementary to the first locking portion 203b and the second locking portion 203c. By fitting and locking the first locking portion 203b or the second locking portion 203c of the shaft cylinder 203 with the locked portion 209a of the cap 209, the cap 209 can be fitted onto the front end or rear end of the shaft cylinder 203.
[0064] Alternatively, the first and second locking portions of the shaft 203 may be formed as recesses, and the locked portion of the cap 209 may be formed as a convex portion, so that the cap 209 is fitted onto the front or rear end of the shaft 203. Alternatively, the first and second locking portions of the shaft 203 and the locked portion of the cap 209 may all be formed as convex portions, so that the locked portion of the cap 209 overcomes and locks onto the first or second locking portion of the shaft 203, thereby fitting the cap 209 onto the front or rear end of the shaft 203.
[0065] Figure 22 is a longitudinal cross-sectional view of the rear end of the barrel 203 of the retractable writing instrument 200 shown in Figure 19. In Figure 22, the lower part is the front of the retractable writing instrument 200. An outer cam 220, which constitutes part of the retractable mechanism 210, is provided on the inner surface of the rear end of the barrel 203. The outer cam 220 has four protruding first cam portions 221 arranged at equal intervals along the circumferential direction on the inner surface of the barrel 203. The first cam portions 221 extend in the front-rear direction, and an annular portion 221a is formed at the rear end, which is connected to each other in an annular shape. A first cam surface 222 is provided on the front end surface of the first cam portion 221. The first cam surface 222 is a surface that is inclined along the circumferential direction. Four guide grooves 223 extending in the front-rear direction are defined between the four first cam portions 221. Therefore, the outer cam 220 has four first cam portions 221 and four guide grooves 223. A regulating surface 224 is provided on the front end surface of the annular portion 221a to which the first cam portion 221 is connected at the rear end of the guide groove 223.
[0066] A through hole 203a is formed in the rear end surface of the shaft cylinder 203 so that the knock cam 230, which will be described later, can be inserted into it. The annular portion 221a, which is the entrance portion of the through hole 203a, is formed to be lower in height from the inner circumferential surface of the shaft cylinder 203 compared to other portions. A fourth cam surface 225 is provided on the rear end surface of the first cam portion 221, i.e., on the surface of the annular portion 221a, at a corresponding position behind the first cam surface 222, and is inclined in the same direction as the first cam surface 222.
[0067] Figure 23 is a perspective view of the knock cam 230 of the retractable writing instrument 200 shown in Figure 19. In Figure 23, the lower part is Cap 209This is the front of the knock cam 230. The rear of the knock cam 230 is provided with a fitting portion 235 that fits onto the end to form the closed end of the cap 209. The knock cam 230 has four projection-like second cam portions 231 that are spaced evenly along the circumferential direction and extend in the front-rear direction. Each of the second cam portions 231 is movably positioned in the front-rear direction within the guide groove 223 of the outer cam 220. The front end surface of the second cam portion 231 is provided with a second cam surface 232. The second cam surface 232 is a surface that is inclined along the circumferential direction, similar to the first cam surface 222 and the fourth cam surface 225 of the outer cam 220. The circumferential side surface of the second cam portion 231 is provided with a first contact surface 233. The rear end surface of the second cam portion 231 is provided with a locking surface 234.
[0068] Furthermore, the second cam portion 231 is formed such that the circumscribed circle in the cross-section of the second cam portion 231 is smaller than the inscribed circle in the cross-section of the annular portion 221a of the outer cam 220. Therefore, as will be described later, when the cap 209 is fitted to the rear end of the shaft cylinder 203, the second cam portion 231 of the knock cam 230 is positioned within the guide groove 223 without interfering with the annular portion 221a of the outer cam 220.
[0069] Figure 24 is a perspective view of the rotor 240 of the retractable writing instrument 200 shown in Figure 19. In Figure 24, the lower part is the front of the retractable writing instrument 200. The rotor 240 has four projection-like third cam portions 241 that are arranged at equal intervals along the circumferential direction and extend in the front-rear direction. The four third cam portions 241 constitute an inner cam. Each of the third cam portions 241 is positioned to be movable in the front-rear direction within the guide groove 223 of the outer cam 220. A cam receiving surface 242 is provided on the rear end surface of the third cam portion 241. The cam receiving surface 242 is a surface that is inclined along the circumferential direction, facing the first cam surface 222 of the outer cam 220 and the second cam surface 232 of the knock cam 230. The rear end surface of the refill 5, which is biased by the spring 6, abuts against the front end surface of the rotor 240. Therefore, the rotor 240 is always biased rearward via the refill 5 by the spring 6. A second contact surface 243 is provided on the circumferential side surface of the third cam portion 241.
[0070] Figure 25 is a perspective view of the retractable mechanism 210 of the retractable writing instrument 200 shown in Figure 19 in the writing state. In the writing state, Figure 26 While referring to Later As shown, the third cam portion 241 of the rotor 240 engages with the first cam portion 221 of the outer cam 220. At this time, the rotation of the rotor 240 is restricted by the rotor 240 contacting the knock cam 230 in the circumferential direction, specifically by the second contact surface 243 contacting the first contact surface 233, thereby maintaining the writing state.
[0071] Figure 26 is a schematic diagram of the retractable mechanism 210 that shows the switching of the retractable writing instrument 200 from the non-writing state to the writing state, as shown in Figure 19. Specifically, Figure 26 is a schematic diagram showing the positional relationship between the outer cam 220, the knock cam 230, and the rotor 240, showing the positions of the second cam portion 231 of the knock cam 230 and the third cam portion 241 of the rotor 240 relative to the outer cam 220 when it is unfolded in the circumferential direction. In the figure, the bottom is the front of the retractable writing instrument 200, and the top is the rear of the retractable writing instrument 200. The rotor 240 is given rotational force by the cooperation of the first cam surface 222 of the outer cam 220 or the second cam surface 232 of the knock cam 230 and the cam receiving surface 242 of the rotor 240, and rotates in one direction around the central axis. Therefore, the rotor 240 moves from right to left in Figure 26.
[0072] Incidentally, when not writing, the cap 209 is fitted to the front end of the barrel 203. When the cap 209 is fitted to the front end of the barrel 203, the front end surface of the knock cam 230 is in contact with the front end surface of the barrel 203 (Figure 19). By removing the cap 209 from the front end of the barrel 203 and fitting it completely to the rear end, the knock cam 230 is inserted into the barrel 203 through the through hole 203a and, in cooperation with the rotor 240, switches from the non-writing state to the writing state (Figure 21). Figure 26 will explain the process step by step, starting from the state shown in Figure 20, immediately after the cap 209 is placed on the rear end of the barrel 203.
[0073] Figure 26(A) is a schematic diagram of the retractable mechanism 210 in the non-writing state immediately after the cap 209 is positioned at the rear end of the barrel 203. In the non-writing state, the third cam portion 241 of the rotor 240, which is biased rearward by the spring 6 via the refill 5, is positioned rearward within the guide groove 223 between the outer cams 220. The retraction of the rotor 240 is restricted by the rear end of the third cam portion 241 engaging with the regulating surface 224 of the outer cam 220. Therefore, in this state, the writing portion 4 is retracted into the barrel 203.
[0074] The cap 209 is placed haphazardly on the rear end of the shaft 203 by the user. As a result, the second cam portion 231 of the knock cam 230 may not be positioned in the same location as the guide groove 223 of the outer cam 220. Figure 26(A) shows a state in which the second cam portion 231 of the knock cam 230 is positioned circumferentially offset from the guide groove 223 of the outer cam 220.
[0075] When the cap 209 is pressed against the shaft cylinder 203 from the state shown in Figure 26(A), the second cam surface 232 of the knock cam 230 and the fourth cam surface 225 of the outer cam 220 cooperate to rotate the cap 209 so that the second cam portion 231 of the knock cam 230 enters the guide groove 223. That is, the knock cam 230, which is pressed forward, receives a circumferential component force from the fourth cam surface 225, and the knock cam 230 rotates around its central axis as the second cam surface 232 slides sequentially along the fourth cam surface 225 and the cam receiving surface 242. The second cam portion 231 of the knock cam 230 moves along the fourth cam surface 225 of the outer cam 220 and the cam receiving surface 242 of the rotor 240 in that order until it contacts the side surface of the first cam portion 221 of the outer cam 220. As a result, the second cam portion 231 of the knock cam 230 is positioned at the entrance of the guide groove 223 of the outer cam 220 (Figure 26(B)).
[0076] From the state shown in Figure 26(B), the knock cam 230 and rotor 240 are further advanced by pressing the cap 209 against the shaft cylinder 203 against the biasing force of the spring 6. At this time, the second cam portion 231 of the knock cam 230 and the third cam portion 241 of the rotor 240 advance within the guide groove 223. The knock cam 230 and rotor 240 are subjected to circumferential force components in opposite directions via the inclined surfaces of the second cam surface 232 and the cam receiving surface 242, but their circumferential movement, i.e., rotation, is restricted by the contact between the second cam portion 231 of the knock cam 230 or the third cam portion 241 of the rotor 240 and the side surface of the first cam portion 221 of the outer cam 220.
[0077] As the knock cam 230 and rotor 240 move further forward, the rear end of the third cam portion 241 of the rotor 240 passes the front end of the outer cam 220, i.e., the first cam portion 221, in the front-rear direction, causing the first cam surface 222 and the second cam surface 232 to coincide, and the restriction on the rotation of the rotor 240 by the outer cam 220 is released (Figure 26(C)). As a result, the rotor 240, which is biased to the rear, receives circumferential force components from the second cam surface 232 and the first cam surface 222, and the rotor 240 rotates around its central axis as the cam receiving surface 242 slides sequentially over the second cam surface 232 and the first cam surface 222 (Figure 26(D)).
[0078] The third cam portion 241 of the rotor 240 moves along the second cam surface 232 of the knock cam 230 and the first cam surface 222 of the outer cam 220 in that order until it contacts the side surface of the second cam portion 231 of the knock cam 230. That is, the rotation of the rotor 240 is stopped and restricted when the second contact surface 243 contacts the first contact surface 233 of the knock cam 230. At this time, the retraction of the rotor 240, which is biased to the rear, is restricted by the engagement of the third cam portion 241 with the first cam portion 221 (Figure 26(E)). In short, by the rotor 240 engaging with the outer cam 220, the writing portion 4 of the refill 5, which is positioned in front of the rotor 240, is maintained in a state where it protrudes from the barrel 203, and the retractable writing instrument 200 is in the writing state. At this time, the second locking portion 203c of the shaft cylinder 203 and the locked portion 209a of the cap 209 engage and lock together, thereby fitting the cap 209 onto the rear end of the shaft cylinder 203.
[0079] Although the spring 6 biases the rotor 240 backward via the refill 5, in the writing state, this biasing force is supported only by the outer cam 220, as shown in Figure 26(E). Therefore, in the writing state, no force acts to retract the knock cam 230, i.e., the cap 209.
[0080] Figure 27 is a schematic diagram of the retractable mechanism 210 that shows the switching from the writing state to the non-writing state of the retractable writing instrument 200 shown in Figure 1. In Figure 27, the positional relationship between the outer cam 220, the knock cam 230, and the rotor 240 is shown in the same way as in Figure 26.
[0081] Figure 27(A) is a schematic diagram of the retractable mechanism 210 of the retractable writing instrument 200 in the writing state, and is the same schematic diagram as Figure 26(E). From the state in Figure 27(A), the knock cam 230 is retracted by grasping the cap 209 and removing it from the rear end of the barrel 203. When the knock cam 230 retracts, the front end of the second cam portion 231 of the knock cam 230 passes the rear end of the rotor 240, i.e., the third cam portion 241, in the front-rear direction, and the first cam surface 222 and the second cam surface 232 coincide, and the restriction of the rotation of the rotor 240 by the knock cam 230 is released (Figure 27(B)). As a result, the rotor 240, which is biased to the rear, receives a circumferential component force from the first cam surface 222, and the rotor 240 rotates further around the central axis as the cam receiving surface 242 slides sequentially between the first cam surface 222 and the second cam surface 232 (Figure 27(C)).
[0082] The third cam portion 241 of the rotor 240 moves along the first cam surface 222 of the outer cam 220 and the second cam surface 232 of the knock cam 230 in that order, until it contacts the side surface of the first cam portion 221 of the outer cam 220. As a result, the rotation of the rotor 240 is stopped and restricted (Figure 27(D)). In this state, since the rotor 240 is disengaged from the outer cam 220, the rotor 240 and the knock cam 230 retract into the guide groove 223 due to the biasing force of the spring 6 and the force that removes the cap 209. The retraction of the rotor 240 is restricted by the rear end of the third cam portion 241 engaging with the restricting surface 224 of the outer cam 220, and the cap 209 is removed (Figure 27(E)). In short, by disengaging the rotor 240 from the outer cam 220, the writing portion 4 of the refill 5, which is positioned in front of the rotor 240, remains retracted into the barrel 203, and the retractable writing instrument 200 is in a non-writing state.
[0083] In summary, the retractable writing instrument 200 is configured such that, as the rear end of the barrel 203 is inserted into the cap 209, the knock cam 230 presses against the rotor 240, causing the rotor 240 to advance and rotate. The rotation of the rotor 240 is restricted by circumferential contact with the knock cam 230, causing the rotor 240 to engage with the outer cam 220 and enter the writing state. Specifically, the retractable writing instrument 200 is configured such that, as the rear end of the barrel 203 is inserted into the cap 209, the second cam surface 232 presses against the cam receiving surface 242, causing the rotor 240 to advance and rotate. The second contact surface 243 of the third cam portion 241 of the rotor 240 contacts the first contact surface 233 of the second cam portion 231 of the knock cam 230, thereby restricting the rotation of the rotor 240.
[0084] Furthermore, the retractable writing instrument 200 is configured such that, as the rear end of the barrel 203 is inserted into the cap 209, the second cam surface 232 and the fourth cam surface 225 cooperate to rotate the cap 209 so that the second cam portion 231 enters the guide groove 223. In addition, the retractable writing instrument 200 is configured such that, when the cap 209 is removed from the rear end of the barrel 103, the restriction on the rotation of the rotor 240 by the knock cam 230 is released, allowing the rotor 240 to rotate further, and the rotor 240 disengages from the outer cam 220, resulting in a non-writing state. Furthermore, the retractable writing instrument 200 is configured such that a second locking portion 203c is formed on the outer surface of the barrel 203, and a locked portion 209a is formed on the inner surface of the cap 209, and when the rear end of the barrel 203 is inserted into the cap 209, the second locking portion 203c and the locked portion 209a are locked together, and the rotor 240 comes into contact with the knock cam 230 in the circumferential direction.
[0085] According to the third embodiment described above, a retractable writing instrument 200 equipped with a novel retractable mechanism 210 can be provided. This prevents unintended contact of the writing part, thereby preventing contamination or injury.
[0086] In other words, as described above with reference to Figure 27, in the retractable writing instrument 200, the writing state can be switched from non-writing state to writing state by fitting the cap 209 onto the rear end of the barrel 203, and the writing state can be switched from writing state to non-writing state by removing the cap 209 from the rear end of the barrel 203. To put it another way, the writing part 4 remains protruding from the barrel 203 only while the cap 209 is fitted onto the rear end of the barrel 203. Therefore, when writing is finished and the user tries to fit the cap 209 onto the front end of the barrel 203, the writing part 4 is always retracted into the barrel 203, so the inside of the cap 209 does not come into contact with the writing part 4 and get stained with ink. Also, when trying to fit the cap 209 onto the front end of the barrel 203, the user does not accidentally touch the writing part 4 and get ink on their hand or get injured by the sharp tip of the writing part 4.
[0087] In the retractable writing instrument 200, the cap 209 must always be fitted onto the rear end of the barrel 203 in order to write. This prevents situations where the cap 209 is removed and left on the desk while writing, thus preventing accidental dropping or loss of the cap 209. Furthermore, in the non-writing state with the cap 209 fitted onto the front end of the barrel 203, no internal parts protrude outward from the through hole 203a at the rear end of the barrel 203. For example, the rear end of the rotor 240 is located in front of the rear end of the barrel 203, thus preventing accidental operation and providing excellent design.
[0088] Each of the retractable writing instruments 1, 100, and 200 has an outer cam, a knock cam, and a rotor, and has a first cam section, a second cam section, and a third cam section. Although there were four of each of the first cam section, second cam section, and third cam section, there may be two, three, or five or more.
[0089] In the retractable writing instrument 1, all or part of the operating part 7 or clip 8 may be configured as an erasing member for erasing the writing made by the writing instrument. In the retractable writing instrument 100, all or part of the operating part 107 or cover member 108 may be configured as an erasing member for erasing the writing made by the writing instrument. In the retractable writing instrument 200, all or part of the cap 209 (for example, the fitting part 235 of the knock cam 230) may be configured as an erasing member for erasing the writing made by the writing instrument. The refill 5 may contain thermochromic ink. In this case, the writing instrument is a thermochromic writing instrument, and the writing made by the writing instrument can be thermochromic due to the frictional heat generated when it is rubbed by the friction body which is the erasing member. As a writing instrument, a ballpoint pen containing thermochromic ink, a mechanical pencil containing a thermochromic lead, a pencil holder, etc. can also be used. It may also be used as a writing instrument containing eraser-erasable ink that can be erased with an eraser.
[0090] Here, thermochromic ink refers to ink that maintains a predetermined color (first color) at room temperature (e.g., 25°C), changes to a different color (second color) when heated to a predetermined temperature (e.g., 60°C), and then returns to its original color (first color) when cooled to a predetermined temperature (e.g., -5°C). In writing instruments using thermochromic ink, the second color is made colorless, and the process of heating the line written with the first color (e.g., red) to make it colorless is referred to here as "erasing." Therefore, friction heat is generated by rubbing the writing surface on which the line is written with a friction element acting as an eraser, thereby changing the line to colorless, i.e., erasing it. Of course, the second color may be a color other than colorless. [Explanation of Symbols]
[0091] 200 Retractable writing instrument 203 Shaft cylinder 209 Cap 210 Appearance mechanism 220 external cam 221 First cam section 222 First cam surface 223 Guide groove 224 Regulatory aspects 225 Fourth cam surface 230 Knockcam 231 Second cam section 232 Second cam surface 233 First contact surface 234 Locking surface 235 Fitting part 240 rotor 241 Third cam section 242 Cam bearing surface 243 Second contact surface
Claims
1. The barrel and, A cap having a knock cam and being fitted to the rear end of the shaft cylinder, A rotor biased to the rear within the shaft cylinder, The shaft comprises an external cam provided on the inner surface of the aforementioned shaft cylinder, The knock cam and the outer cam are configured to cooperate with the rotor to rotate the rotor, and the retractable writing instrument is capable of switching between a writing state in which the rotor is engaged with the outer cam and a non-writing state in which the rotor is disengaged from the outer cam. A retractable writing instrument characterized in that, as the rear end of the barrel is inserted into the cap, the knock cam presses against the rotor, causing the rotor to advance and rotate, and the rotation of the rotor is restricted by circumferential contact with the knock cam, causing the rotor to engage with the outer cam and enter a writing state.
2. The outer cam has a plurality of first cam portions arranged circumferentially on the inner surface of the shaft cylinder and having a first cam surface on its front end, and a plurality of guide grooves extending in the front-rear direction defined between the plurality of first cam portions. The knock cam is configured to be movable in the front-rear direction within the guide groove and has a second cam portion with a second cam surface on its front end surface. The rotor is configured to be movable in the front-rear direction within the guide groove and has a third cam portion on its rear end surface that has a cam receiving surface that cooperates with the first cam surface and the second cam surface. The retractable writing instrument according to claim 1, wherein as the rear end of the barrel is inserted into the cap, the second cam surface presses against the cam receiving surface, causing the rotor to advance and rotate, and the side surface of the third cam portion of the rotor comes into contact with the side surface of the second cam portion of the knock cam, thereby restricting the rotation of the rotor.
3. The retractable writing instrument according to claim 2, wherein the first cam portion has a fourth cam surface on its rear end surface, and the second cam surface and the fourth cam surface cooperate as the rear end of the barrel is inserted into the cap, causing the cap to rotate so that the second cam portion enters the guide groove.
4. The retractable writing instrument according to claim 1, wherein, in the writing state, when the cap is removed from the rear end of the barrel, the restriction on the rotation of the rotor by the knock cam is released, the rotor rotates, and the rotor disengages from the outer cam, resulting in a non-writing state.
5. A retractable writing instrument according to claim 1, wherein a locking portion is formed on the outer surface of the barrel, a locked portion is formed on the inner surface of the cap, and the rotor is configured to come into contact with the knock cam in the circumferential direction when the locking portion and the locked portion are locked together as the rear end of the barrel is inserted into the cap.
Citation Information
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