EP1422075B1

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Info

Publication number: EP1422075B1
Application number: EP20030024402
Authority: EP
Inventors: Hiroyuki Micro Co. Ltd. Kanari; Yousuke Micro Co. Ltd. Ishii
Original assignee: Micro Co Ltd
Current assignee: Micro Co Ltd
Priority date: 2002-11-20
Filing date: 2003-10-22
Publication date: 2006-05-24
Anticipated expiration: 2023-10-22
Also published as: DE60305415T2; EP1422075A1; JP3793968B2; JP2004167830A; DE60305415D1

Description

The present invention relates to a writing instrument according to the preamble ofclaim 1.
Such a writing instrument is described in US-A-5,915,867. In this known writing instrument a sleeve is provided through which an end portion of a writing component passes during movement of the writing component between a writing position and a haust position. A cup plate is connected to the sleeve for opening and closing the wall of the sleeve. In the haust position the cap plate is kept close by biasing means acting through string-like members connected to the cup plate.
In conventional writing instruments, such as a marker, a writing tip is maintained in an airtight condition so that it will not be dried when it is not used. Usually, in the case of a cap-type writing instrument, a cap is detachably attached to the front end of a barrel housing a writing component, and an airtight chamber surrounding the writing tip is formed by attaching the cap. In some cases, a soft material such as a rubber piece is provided in the cap so that it will abut on the writing tip. Further, in a case of a capless-type writing instrument, an airtight structure has been known wherein an airtight chamber surrounding the writing tip is disposed at the front portion of a barrel, in which the front end opening portion of the airtight chamber is opened and closed by a biasing member such as a spring so that the airtight chamber is opened when a writing component (e.g., a refill) advances and the airtight chamber is closed when the writing component retracts.
However, use of the conventional cap-type writing instrument requires the cumbersome step of removing the cap prior to a writing operation. In the case of the conventional capless-type writing instrument, since a spring is needed to open and close the opening portion, the number of parts becomes large, the manufacture and assembly thereof is complicated and expensive, and the resulting writing instrument tends to have a large diameter.
Moreover, conventional writing instruments having an airtight structure for the writing component are available. One such writing instrument has a rotating cam-type feeding mechanism disposed in a barrel for moving the writing component forward and backward. In general, such a rotating cam-type feeding mechanism is disposed in a rear portion of the barrel and has a rotational cam which abuts on a rear end of a writing component, a guide cam which allows the rotational cam to transfer in an axial direction, and an outer cam which is formed on an inner side of the barrel and guides the transfer of the rotational cam. However, the conventional rotating cam-type feeding mechanism is associated with a large number of parts and its manufacture and assembly is complicated. Furthermore, since a feeding mechanism is provided at the rear portion of the barrel, the entire length of the writing instrument tends to be long. Any attempt to form the conventional rotating cam-type feeding mechanism with a compact structure will require the use of an undesirable short writing component. Accordingly, if an airtight structure for maintaining the writing tip in an airtight manner is disposed at the front portion of the barrel, the entire length of the writing component is increased.

SUMMARY OF THE INVENTION

The present invention is directed to a writing instrument which overcomes the foregoing drawbacks of the conventional art.
It is an object of the present invention to provide a writing instrument for which it is not necessary to detach a cap when it is used, and in which by an operation of shifting a barrel or a writing component in an axial direction, the writing tip of the writing component can be protruded or the writing tip can be maintained in an airtight manner.
It is another object of the present invention to provide a writing instrument having an airtight structure for which no spring is needed for the airtight mechanism, thereby reducing the number of parts.
It is a further object of the present invention to provide a writing instrument having an airtight mechanism in which the writing component can be moved by a rotating cam-type feeding mechanism and which can accomodate a long writing component.
It is still another object of the present invention to provide a writing instrument which has a simple and compact structure with a small number of parts and which is economical to manufacture.
this object is achieved by the features cited in the characterising portion ofclaim 1.
The foregoing and other objects of the present invention are carried out by a writing instrument comprising a cylindrical barrel having an aperture at its front end and a writing component housed in the barrel and having a writing tip and a shoulder located behind the writing tip. The barrel and the writing component are relatively movable in an axial direction of the barrel between a writing position at which the writing tip protrudes from the aperture and a housed position at which the writing tip is housed inside the barrel. An airtight sleeve is fitted on the front portion of the writing component in such a manner that the airtight sleeve is movable between an advanced position and a retracted position. The airtight sleeve has, at a front portion thereof, a bore through which the front portion of the writing component passes. An inner raised portion is formed in the airtight sleeve so that when the airtight sleeve is located at the retracted position, the inner raised portion contacts the shoulder of the writing component in an airtight manner. The contact between the inner raised portion of the airtight sleeve and the shoulder of the writing component is disengageable when the airtight sleeve stops at the advanced position.
A cap plate is pivotally fitted on the airtight sleeve so that the bore of the airtight sleeve may be opened or closed. A projecting rib is disposed at a rear side of the cap plate so that when the airtight sleeve moves from the advanced position to the retracted position, the projecting rib abuts on an inner side of the barrel so as to rotate the cap plate in such a direction that the cap plate is pressed against the bore and closes the bore. The barrel has a window hole into which the projecting rib enters when the airtight sleeve moves from the retracted position to the advanced position so as to allow the rotational movement of the cap plate to open the bore of the airtight sleeve.
The writing instrument of the present invention may be constructed so that the barrel is moved relative to the writing component or the writing component is moved relative to the barrel. According to the present invention, when the writing component is moved by a rotating-cam type feeding mechanism, a writing instrument having the rotating-cam type feeding mechanism and the airtight sleeve in the forward portion of the barrel is provided. The rotating cam-type feeding mechanism comprises a rotational cam connected to the writing component for undergoing rotational movement and axial movement in the axial direction, an outer cam having a cam groove for guiding movement of the rotational cam in the axial direction, and a guide cam connected to a rear end of the front piece of the tubular body and having a cam element for rotating the rotational cam
When the barrel or the writing component moves from the housed position to the writing position, the airtight sleeve moves together toward the advanced position in such a state that the inner raised portion of the airtight sleeve contacts the shoulder of the writing component. At the advanced position of the airtight sleeve, the contact between the shoulder of the writing component and the inner raised portion of the airtight sleeve is disengaged. When the projecting rib confronts the window hole of the barrel, the projecting rib enters into the window hole and, at the same time, the cap plate is opened and the writing tip of the writing component protrudes from the aperture of the barrel. In this state, the writing instrument can be used for writing.
When the barrel or the writing component moves from the writing position toward the housed position, the inner raised portion of the airtight sleeve contacts the shoulder of the writing component. The airtight sleeve then moves together with the writing component toward the retracted position, the cap plate is pressingly fitted to the bore by the projecting rib, the bore of the airtight sleeve is closed, and the periphery of the writing tip is airtightly surrounded, thereby preventing drying of the writing tip.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the preferred embodiments of the invention, will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

Fig. 1 is a partial cross-sectional view of a writing instrument according to an embodiment of the present invention in which the writing component is shown in a housed position;
Figs. 2(A) and 2(B) show enlarged explanatory views of part (A) and part (B), respectively, in Fig. 1;
Fig. 3 is an exploded cross-sectional view of a barrel and an airtight sleeve of the writing instrument according to the present invention;
Fig. 4 is a perspective view of the airtight sleeve;
Fig. 5 is a partial cross-sectional view of the writing instrument of the present invention showing a state where the airtight sleeve is located at an advanced position;
Fig. 6 is a partial cross-sectional view of the writing instrument of the present invention showing a state where a writing tip of the writing instruments protrudes from the barrel;
Fig. 7 is a partial cross-sectional view of the writing instrument of the present invention showing a cap plate of the airtight sleeve disposed in a window hole of the barrel;
Fig. 8 is a partially cutaway view showing another embodiment of the writing instrument according to the present invention;
Fig. 9 is a cross-sectional view of a main barrel of the main body of the writing instrument of the present invention;
Figs. 10(A)-10(C) are a front view, a side view and a cross-sectional view, respectively, of a rotational cam of the writing instrument according to the present invention;
Figs. 11(A) and 11(B) are a cross-sectional view and a side view, respectively, show a front piece of the writing instrument according to the present invention;
Fig. 12 is a perspective view of the airtight sleeve of the writing instrument according to the present invention;
Fig. 13 is an exploded partial cross-sectional view of a barrel main body, a rotational cam, an airtight sleeve and a front piece of a writing instrument according to the present invention;
Figs. 14(A)-14(C) are explanatory views of movement states of components of the writing instrument according to the present invention where Fig. 14(A) shows when the writing component is located at a housed position, Fig. 14(B) shows when the airtight sleeve moves to an advanced position, and Fig. 14(C) shows when a cap plate is opened; and
Figs. 15(A)-15(C) are explanatory views of movement states of components of the writing instrument according to the present invention where Fig. 15(A) shows a state in which the writing tip protrudes a little from an aperture, Fig. 15(B) shows a state in which the writing tip protrudes more from the aperture, and Fig. 15(C) shows a state in which the writing component is held at a writing position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention is susceptible of embodiments in many different forms, this specification and the accompanying drawings disclose only some forms as examples of the use of the invention. The invention is not intended to be limited to the embodiments so described, and the scope of the invention will be pointed out in the appended claims.
The writing instrument of the present invention has a cylindrical barrel having an aperture at its front end and a writing component housed in the barrel. The writing component contains volatile writing constituents, such as a marker, a water-based ink pen, a water-based ball point pen, a correction pen and a highlighter pen, and has a writing tip at its front end. The barrel and the writing component are relatively movable in an axial direction of the barrel between a writing position, where the writing tip protrudes outwardly from the aperture, and a housed position, where the writing tip is housed inside the barrel.
Referring now to the drawings in detail, Figs. 1-7 show a writing instrument according to a first embodiment of the present invention. As described in detail below, in the embodiment shown in Figs. 1-7 a tubular member in the form of a generallycylindrical barrel 2 is movable in an axial direction relative to awriting component 1.
With reference to Figs. 1-2, thebarrel 2, which is generally cap-shaped in this embodiment, extends in an axial direction and is attached to a forward end portion of the writing component 1 (e.g., a refill). Thebarrel 2 is preferably made of a plastic material and moves between a housed position (Fig. 1), where awriting tip 3 of thewriting component 1 is housed inside the barrel, and a writing position (Fig. 6 as further described below), where thewriting tip 3 protrudes from anaperture 4 formed at the front end of thebarrel 2. In this embodiment, thebarrel 2 can be slidingly moved in an axial direction of thewriting component 1. The barrel may be constructed so that, for example, it moves in an axial direction in a spiral movement by screw coupling the barrel to the writing component (not shown).
On the outer periphery of alarge diameter portion 5 of thewriting component 1, alock portion 6 is formed and, correspondingly,engagement portions 7, 8 are disposed in thebarrel 2 which engage with thelock portion 6 at the writing position and the housed position, respectively. Thebarrel 2 is held at the housed position by engaging theengagement portion 7 with thelock portion 6 and at the writing position by engaging theengagement portion 8 with thelock portion 6.
Anairtight sleeve 9 is disposed in thebarrel 2 so that it surrounds thewriting tip 3. As shown in Fig. 4, theairtight sleeve 9 comprises a tubular member having a generally rectangular-shaped outer surface portion and a generally cylindrical-shaped inner surface portion. Theairtight sleeve 9 is movable forward and backward between the advanced position and the retracted position in a predetermined range without rotation, and is fitted at a front portion of thewriting component 1.
Theairtight sleeve 9 has an inner raisedportion 11 adapted to contact ashoulder 10 formed on thewriting component 1 in an airtight manner. The airtight contact between the inner raisedportion 11 of theairtight sleeve 9 and theshoulder 10 of thewriting component 1 is designed to be releasable when theairtight sleeve 9 stops at the advanced position. More specifically, the airtight contact between these components is released when theairtight sleeve 9 stops at the advanced position by moving thebarrel 2 in such a direction that thewriting tip 3 of thewriting component 1 protrudes outwardly from theaperture 4 of thebarrel 2.
Theairtight sleeve 9 has abore 12 at a front end portion thereof through which thewriting tip 3 of thewriting component 1 passes. The front side of thebore 12 has a slantedopening edge 13 which slants at an angle of at most about 60°, preferably about 45°, relative to the axis of thebarrel 2. Theairtight sleeve 9 also has acap plate 15 which is connected to a lower side edge of thebore 12 and which can be opened and closed via anintegral plastic hinge 14. As shown in Fig. 4, thehinge 14 extends in the widthwise direction of thecap plate 15 and, as a result, thecap plate 15 is closely and securely contacted with the entire edge of the slantedopening edge 13.
A projectingrib 17 is disposed on a rear side of thecap plate 15 so that when theairtight sleeve 9 moves toward the retracted position, the projecting rib abuts on aninner side 16 of thebarrel 2 to rotate thecap plate 15 and press the cap plate toward the slantedopening edge 13. The projectingrib 17 may be formed in any appropriate shape. In the embodiment shown in Fig. 4, the projectingrib 17 is generally triangular-shaped in cross-section with one end of the triangle being connected to a central portion of thecap plate 15. Furthermore, the projectingrib 17 may be formed with a solid or hollow body. If the projectingrib 17 is formed with a hollow body having an appropriate elasticity, as shown in Fig. 4, or formed by using an appropriate elastic piece, thecap plate 15 can be closely contacted to the slantedopening edge 13 with effective elasticity.
Thebarrel 2 has awindow hole 18 through which the projectingrib 17 enters when theairtight sleeve 9 moves toward the advanced position. By this structure, when thecap plate 15 abuts on thewriting tip 3 and is thereby pressed, the projectingrib 17 enters into thewindow hole 18 and thecap plate 15 is allowed to rotate and released.
Thewriting component 1 has anintermediate portion 19 between theshoulder 10 and thelarge diameter portion 5. Theintermediate portion 19 is held elastically by a holdingmember 20 of thebarrel 2. As shown in Fig. 3, the holdingmember 20 is generally conical-shaped and hasslits 21. When theshoulder 10 of thewriting component 1 is pressingly inserted from the large diameter side and passed through it toward the small diameter side of the holdingmember 20, thebarrel 2 can be installed so that it will not separate from thewriting component 1. In the embodiment shown in Fig. 3, the holdingmember 20 is formed in one piece with thebarrel 2. Alternatively, the holdingmember 20 may be a separate component which is integrally connected to thebarrel 2.
Referring to Figs. 1 and 3, thebarrel 2 comprises afront piece 22, which has theaperture 4 and thewindow hole 18, and a barrelmain body 23 connected to thefront piece 22. Theairtight sleeve 9 is attached to thefront piece 22 of the barrel. Aguide wall 24 is provided at an inner side of thefront piece 22 to guide a side surface of theairtight sleeve 9. Aguide groove 26 is formed on an the outer side of thefront piece 22 for receiving aprojection 25 extending from an outer surface of theairtight sleeve 9. Aflange 27 of theairtight sleeve 9 is adapted to abut with a stop element orstopper 28 formed at a rear end portion of thefront piece 22. Acircumferential groove 30 is formed on the periphery of thefront piece 22 for receiving aprojection 29 of the barrelmain body 23 to prevent detachment of thefront piece 22 from the barrelmain body 23. Thefront piece 22 also has alongitudinal groove 32 for receiving aprojection 31 of the barrelmain body 23 to prevent relative rotation between thefront piece 22 and the barrelmain body 23.
According to the present invention, the barrelmain body 23 functions as a cap and also functions as a grip during a writing operation. In order to provide a comfortable grip during a writing operation, the barrel main body may have a multi-layer structure (not shown) wherein a basal portion is formed with a hard layer and the surface portion is formed with a soft layer by, e.g., two-color molding or an injection molding process. Aclip 33 is disposed on the outside of the barrelmain body 23.
Accordingly, as shown in Fig. 1, thebarrel 2 is maintained at the housed position where theengagement portion 7 engages with thelock portion 6 of thewriting component 1. Further, thewriting tip 3 is housed in theairtight sleeve 9, the inner raisedportion 11 is in contact with theshoulder 10, and thecap plate 15 is pressingly contacted to the slantedopening edge 13 by the projectingrib 17, whereby the inside of theairtight sleeve 9 is kept in an airtight condition and thewriting tip 3 is prevented from drying.
From the state shown in Fig. 1, if thebarrel 2 is moved toward the writing position (rightward in Fig. 1), thelock portion 6 and theengagement portion 7 are disengaged, but the inner raisedportion 11 of theairtight sleeve 9 remains in contact with theshoulder 10, whereby theairtight sleeve 9 is maintained in a standstill condition where it is held by the writing component. Accordingly, relative to thebarrel 2, theairtight sleeve 9 is seen as if it moves from the retracted position toward the advanced position (Fig. 5).
When thestopper 28 of thefront piece 22 abuts on theflange 27 of theairtight sleeve 9, relative movement between theairtight sleeve 9 and thebarrel 2 is inhibited. Theairtight sleeve 9 exists at the advanced position in this state, and since the projectingrib 17 confronts thewindow hole 18, it projects through thewindow hole 18. Accordingly, by further moving thebarrel 2, thecap plate 15 abuts on thewriting tip 3, and thecap plate 15 is rotated and opens thebore 12 of the airtight sleeve. Thewriting tip 3 protrudes from theaperture 4 of the barrel and reaches the writing position (Fig. 6). At this time, since theengagement portion 8 of thebarrel 2 engages with thelock portion 6 of thewriting component 1, the barrel is maintained at the writing position, and the user can perform a writing operation by gripping the barrelmain body 23. The engagement force at thelock portion 6 and theengagement portion 8 at this time is set to such a level that it can withstand the writing force.
When thebarrel 2 is moved from the writing position as shown in Fig. 6 toward the housed position (leftward in Fig. 6), thelock portion 6 and theengagement portion 8 are disengaged by a force greater than the writing force, and theairtight sleeve 9 moves together with the barrel. During movement of theairtight sleeve 9, when the inner raisedportion 11 of theairtight sleeve 9 contacts theshoulder 10 of thewriting component 1, the movement of the airtight sleeve is stopped by the writing component (Fig. 7). When thebarrel 2 is further moved, theairtight sleeve 9 is seen as if it moves toward the retracted position relative to the barrel. As a result, theairtight sleeve 9 abuts on theinner side 16 of thebarrel 2, the projectingrib 17 comes out of thewindow hole 18 and is in slidable contact with theinner side 16, and thecap plate 15 is pressed toward the slantedopening edge 13 and, as shown in Fig. 1, the airtight sleeve reaches the retracted position and holds thewriting component 1 at the housed position.
In the writing instrument as shown in Fig. 1, only by moving the barrel fitted to the front portion of the writing component backward along the axial direction, the cap plate of the airtight sleeve is opened, and the writing tip of the writing component can be protruded from the aperture of the barrel at the time of writing. Further, when the barrel is moved forward from the writing position, the cap plate is rotated by the projecting rib and closes the bore of the airtight sleeve, whereby the cap plate surrounds airtightly the periphery of the writing tip and prevent the writing tip from drying.
Since the cap plate is pressed against the slanted opening edge by the projecting rib, the pressing force can be transferred over the entire cap plate and the cap plate can be closely contacted to the opening edge securely and entirely. In addition, since the opening edge is slanted, the rotation of the cap plate can be made small as compared with the case where the opening edge is set at a right angle, and thus the stress exerted on the hinge is low and the durability is improved. Further, since no special means, such as a spring, is required to pressingly fit the cap plate, and the pressing force can always be imparted by means of the projecting rib, the overall structure of the writing instrument is simplified. Furthermore, since the number of parts of the writing instrument is reduced, it is possible to reduce the diameter of the barrel, assembly of the writing instrument is facilitated, and the writing instrument can be obtained economically.
Figs. 8-14 show another embodiment of the writing instrument according to the present invention in which awriting component 101 is moved in the axial direction relative to abarrel 103.
Fig. 8 is a partially cutaway view showing the writing instrument of the present invention, and shows awriting instrument 102 having awriting component 101 containing volatile writing constituents such as a marker, a water-based ink pen, a water-based ball point pen, a correction pen and a highlighter pen. Thewriting component 101 is housed in abarrel 103, and thebarrel 103 includes afront piece 105 having a barrelmain body 103a and anaperture 104 communicating to its front end.
With reference to Fig. 8 and Fig. 9, an inward steppedportion 106 is formed in thebarrel 103, and aspring 108 is provided between the inward steppedportion 106 and a steppedportion 107 of thewriting component 101 so as to bias thewriting component 101 backwardly. Ahead of the inward steppedportion 106, anouter cam 109 constituting a rotating cam-type feeding mechanism is formed. Theouter cam 109 has, as conventionally known, adeep cam groove 111a and ashallow cam groove 111b which extend in the axial direction so as to guide the movement of arotational cam 110 in the axial direction, and an angle-shapedcam element 112 disposed at a front end thereof for rotating therotational cam 110. In the example shown in Fig. 8, theouter cam 109 is formed in one piece with an inner surface of the forward portion of thebarrel 103. Alternatively, theouter cam 109 may be provided as a separate component in the form of a generally cylindrical-shaped body which is integrally connected to thebarrel 103.
Therotational cam 110 is mounted in thebarrel 103 for undergoing both rotation and axial movement therein, and is generally cylindrical-shaped with an outer diameter dimensioned to be inserted into theouter cam 109. Therotational cam 110 has, on the inner side, a connectingportion 114 which is fitted to aneck portion 113 of the writing component 101 (Fig. 10). Aprojection 115 is provided on the periphery of therotational cam 110 for engagement with thecam grooves 111a, 111b of theouter cam 109. A slantedcam element 116 is provided at a rear end portion of theprojection 115 for engagement with thecam element 112 of theouter cam 109. Acam element 118 for engagement with aguide cam 117 is provided at a forward end of therotational cam 110.
The connectingportion 114 of therotational cam 110 is elastic so that it can be enlarged so that it can be inserted from awriting tip 119 side to aneck portion 113 of thewriting component 101, and when it is inserted up to theneck portion 113, aforward end 121 thereof engages with aflange 120 formed on thewriting component 101 and itsbasal end 123 engages with an intermediate steppedportion 122. Here, therotational cam 110 is loosely fitted to the writing component so that it can be rotated while keeping such a state that it is fitted to the writing component. Therotational cam 110 may be a separate component integrally connected to thewriting component 101 or it may be formed unitarily with thewriting component 101.
As shown in Fig. 11, theguide cam 117 is provided at the rear end of thefront piece 105 ahead of therotational cam 110 and has acam element 124. When theprojection 115 of therotational cam 110 separates or disengages from thecam grooves 111a, 111b of the outer cam, thecam element 118 of therotational cam 110 abuts on thecam element 124 to rotate therotational cam 110. Thecam element 124 confronts thecam element 112 of theouter cam 109 so as to rotate therotational cam 110 by a predetermined angle. Accordingly, on the periphery of thefront piece 105, a circumferential groove 126 (Fig. 11) is formed so that it engages with a latchingprojection 125 formed in the barrel main body (Fig. 9). Further, in order to engage with alongitudinal groove 127 which is formed on the barrel main body and extends in the axial direction, aprojection 128 is provided so that thefront piece 105 is connected to the barrelmain body 103a in a non-rotatable state. The connection between thefront piece 105 and the barrelmain body 103a can be achieved by appropriate connecting means such as a press-fit connection, an adhesive, a latching pin or the like.
The rear end of thewriting component 101 protrudes from the rear end of thebarrel 103 at the housed position. The rear end of thebarrel 103 may be extended rearwardly so that the rear end of the writing component can be housed in the extended portion of the barrel. In this case, in order to operate the writing component from the outside of the barrel, an appropriate operating member such as a push button or the like may be provided (not shown).
By the foregoing construction, when the rear end of thewriting component 101 is directly knocked forwardly or the writing component is indirectly knocked forwardly via an appropriate operating member connected to the writing component (not shown), theprojection 115 of therotational cam 110 separates or disengages from thedeep cam groove 111a of theouter cam 109 and abuts on theguide cam 117 to rotate the rotational cam. When the knocking is stopped, thewriting component 101 retracts a little by thespring 108, and theprojection 115 engages with theshallow cam groove 111b of theouter cam 109. Accordingly, thewriting component 101 is maintained at the writing position in such a state that thewriting tip 119 protrudes from theaperture 104. When thewriting component 101 is knocked again, therotational cam 110 abuts on theguide cam 117 and thus further rotates, and when the knocking is stopped, theprojection 115 engages with thedeep cam groove 111a of theouter cam 109. Thewriting component 101 thereby retracts substantially and is held at the housed position.
In thefront piece 105, anairtight sleeve 129 is provided which is fitted to the front portion of thewriting component 101 so that it surrounds thewriting tip 119 of the writing component. Theairtight sleeve 129 has acap plate 130 at its front side of abore 129a, and when thewriting component 101 moves to the writing position, thecap plate 130 is opened and thewriting component 119 protrudes from the front end of the barrel. Further, when the writing component moves to the housed position, thecap plate 130 is closed and thewriting tip 119 is airtightly held.
Theairtight sleeve 129 has substantially the same function as theairtight sleeve 9 described above with reference to the embodiment of Figs. 1-7. More specifically, theairtight sleeve 129 is disposed at the front portion of thewriting component 101 for undergoing forward and rearward movement in a non-rotatable manner so that when the writing component moves to the writing position, theairtight sleeve 129 moves to the advanced position and thecap plate 130 is opened, and when thewriting component 101 moves to the housed position, theairtight sleeve 129 moves to the retracted position and thecap plate 130 is closed.
With reference to Fig. 12 and Fig. 13, theairtight sleeve 129 is made of a plastic material and is inserted into thefront piece 105 for undergoing forward and rearward movement in such a state that aprojection 131 disposed on the outer side is inserted into aguide groove 132 of thefront piece 105. Theairtight sleeve 129 has an inner raisedportion 134 which extends from an inner surface thereof and is engageable with ashoulder 133 formed on thewriting component 101. The inner raisedportion 134 engages with theshoulder 133 in an airtight manner when thewriting component 101 is located at the housed position (Fig. 14(A)). Thus theairtight sleeve 129 moves together with the movement of thewriting component 101 when the writing component moves toward the writing position. At the rear end of theairtight sleeve 129, aflange 136 is disposed so that it abuts on astopper 135 formed on the inner side of thefront piece 105. Accordingly, when theairtight sleeve 129 advances up to the position where theflange 136 abuts on thestopper 135 as shown in Fig. 14(B), theairtight sleeve 129 stops at this position and is held at the advanced position. When the writing component further advances, the engagement between the inner raisedportion 134 and theshoulder 133 is disengaged, and only the writing component advances.
Thecap plate 130 is pivotably provided by an integrally formedhinge 138 at the basal end of aslanted opening edge 137, and at its rear side, a solid projectingrib 139 is formed. To thefront piece 105, a slidingsurface 140 on which the projectingrib 139 slides and awindow hole 141 in which the projectingrib 139 enters, are provided. When theairtight sleeve 129 is located at the retracted position, the projectingrib 139 slidably contacts the slidingsurface 140 and presses thecap plate 130 against the slantedopening edge 137, thereby closing abore 129a of the airtight sleeve (Fig. 14 (A)).
As described above, when theairtight sleeve 129 moves up to the advanced position, the projectingrib 139 projects into thewindow hole 141 and thecap plate 130 rotates (Fig. 14(C)), whereby it becomes possible to open the bore of theairtight sleeve 129 to allow thewriting tip 119 of thewriting component 101 to protrude outwardly from theaperture 104 of the front piece 105 (Fig. 15(A)). When therotational cam 110 rotates as described above (Fig. 15(B)) to hold thewriting instrument 101 at the writing portion, a writing operation can be conducted as shown in (Fig. 15(C)).
When thewriting component 101 is knocked to retract it from the writing position to the housed position, theshoulder 133 engages with the inner raisedportion 134 during movement (Fig. 14(C)) and theairtight sleeve 129 returns from the advanced position to the retracted position together with movement of thewriting component 101. At this time, the projectingrib 139 disengages from thewindow hole 141 and slides on the sliding surface 140 (Fig. 14(B)), and thecap plate 130 is rotated by the projectingrib 139 and is thereby pressed against the slantedopening edge 137, whereby thewriting tip 119 is airtightly held (Fig. 14(A)). When theshoulder 133 and the inner raisedportion 134 of theairtight sleeve 129 are closely contacted with one another with a strong contact force, the airtight property is enhanced. Accordingly, for example, a spring (not shown) may be provided between theflange 120 of thewriting component 101 and the rear end of theairtight sleeve 129 to bias theairtight sleeve 129 forward.
By the foregoing construction of thewriting instrument 102, since the guide cam which imparts rotation to the rotational cam is integrally formed at the rear portion of the front piece, the number of parts constituting the rotating cam-type feeding mechanism is reduced, thereby providing a writing instrument having a simple construction. Furthermore, since the rotating cam-type feeding mechanism is incorporated into the front portion of the barrel, even if a long writing component is used and incorporated together with the airtight sleeve, the entire writing instrument can be made compact and can be used for a long time since the writing component can be maintained in an airtight condition when it is not used.
From the foregoing description, it can be seen that the present invention comprises an improved writing instrument. It will be appreciated by those skilled in the art that obvious changes and variations can be made to the embodiments described in the foregoing description without departing from the broad inventive concept thereof.

Claims

A writing instrument, comprising:
a tubular member (2, 103) having a longitudinal axis and an aperture (4, 104) at an end thereof; a writing component (1,101) mounted in the tubular member (2, 103) and having a writing tip (3, 119) at an end portion thereof, the tubular member (2, 103) and the writing component (1, 101) being movable relative to one another in axial directions along the longitudinal axis of the tubular member (2, 103) between a writing position at which the writing tip (3, 119) protrudes from the aperture (4, 104) of the tubular member (2, 103) and a housed position at which the writing tip (3, 119) is disposed in the tubular member (2, 103), wherein
an airtight sleeve (9, 129) is connected to the end portion of the writing component in such a manner that the airtight sleeve is movable relative to the tubular member (2, 103) between an advanced position and a retracted position,
the airtight sleeve (9, 129) has a bore (12, 129a) through which the end portion of the writing component (1,101) passes during movement of the writing component between the writing position and the housed position, and
a cap plate (15, 130) is pivotally connected to the airtight sleeve (9,129) for opening and closing the bore (12, 129a) of the airtight sleeve (9, 129),
characterised in that
a projecting rib (17,139)is connected to the cap plate (15, 130) so that when the airtight sleeve (9,129) moves from the advanced position to the retracted position, the projecting rib (17, 139) abuts on an inner surface (16, 140) of the tubular member (2, 103) so as to pivot the cap plate (15,130) in such a direction that the cap plate (15, 130) closes the bore (12, 129a) of the airtight sleeve (9, 129), wherein
the tubular member (2, 103) has a window hole (18,141) into which the projecting rib (17, 139) projects when the airtight sleeve (9,129) moves from the retracted position to the advanced position to allow the cap plate (15, 130) to pivot in a direction to open the bore (12, 129a) of the airtight sleeve (9, 129).
A writing instrument according to Claim 1, wherein the writing component (1,101) has a shoulder (10,133) located behind the writing tip (3, 119); and wherein the airtight sleeve (9,129) has an inner raised portion (11, 134) for engaging with the shoulder (10, 133) of the writing component with an airtight contact when the airtight sleeve (9, 129) is located at the retracted position and for disengaging from the shoulder (10,133) of the writing component when the airtight sleeve (9, 129) is located at the advanced position.
A writing instrument according to Claim 1, wherein an edge of the airtight sleeve (9, 129) proximate the bore (12, 129a) thereof is disposed at an oblique angle relative to a longitudinal axis of the airtight sleeve (9, 129).
A writing instrument according to Claim 1, wherein the airtight sleeve (9,12 9) has a flange (27, 136) at a rear portion thereof; and wherein the tubular member has a stop element (28, 135) for engaging the flange (27, 136) of the airtight sleeve (9, 129) to limit movement of the airtight sleeve (9,129) from the retracted position to the advanced position.
A writing instrument according to Claim 4, wherein the airtight sleeve (9, 129) has a generallly rectangular-shaped portion connected to the flange (27, 136).
A writing instrument according to Claim 1, wherein the tubular member (2) has a main body (23) and a front piece (22) connected to the main body (23); and wherein the airtight sleeve (9) is disposed in the front piece (22) of the tubular member (2).
A writing instrument according to Claim 6, wherein the writing component (1) has a lock portion (6); and wherein the main body (23) of the tubular member (2) has a plurality of engagement portions (7, 8) each for respective engagement with the lock portion (6) of the writing component (1) at the writing position and at the housed position of the writing component (1).
A writing instrument according to Claim 6, further comprising a holding member (20) disposed in the main body (23) of the tubular member (2) for elastically supporting the writing component (1).
A writing instrument according to Claim 6, wherein the airtight sleeve (9) has a projection (25); and wherein the front piece (22) of the tubular member (2) has a guide groove (26) extending in the axial direction for receiving the projection (25) of the airtight sleeve (9).
A writing instrument according to Claim 6, wherein the airtight sleeve (9) has a flange (27) disposed at a rear portion thereof; and wherein the tubular member (2) has a stop element (28) dispiosed at a rear portion of the front piece (22) for engaging the flange (27) of the airtight sleeve (9) to limit movement of the airtight sleeve (9) from the retracted position to the advanced position.
A writing instrument according to Claim 1, further comprising a rotating cam-type feeding mechanism disposed in the tubular member (103) for.moving the writing component (101) in the axial directions.
A writing instrument according to Claim 11, wherein the tubular member (103) has a main body (103a) and a front piece (105) connected to the main body (103a) and wherein the airtight sleeve (129) is disposed in the front piece (105) of the tubular member (103).
A writing instrument according to Claim 12, wherein the rotating cam-type feeding mechanism comprises a rotational cam (110) connected to the writing component (101) for undergoing rotational movement and movement in the axial direction, an outer cam (109) having a cam groove (111a, 111b) for guiding movement of the rotational cam (110) in the axial direction, and a guide cam (117) connected to a rear end of the front piece (105) of the tubular member and having a cam element (124) for rotating the rotational cam (110).
A writing instrument according to Claim 12, wherein the airtight sleeve (129) has a projection (131); and wherein the front piece (105) of the tubular member (103) has a guide groove (132) extending in the axial direction for receiving the projection (131) of the airtight sleeve (129).
A writing instrument according to Claim 12, wherein the airtight sleeve (129) has a flange (136) disposed at a rear portion thereof; and wherein the tubular member (103) has a stop element (135) disposed at a rear portion of the front piece (105) for engaging the flange (136) of the airtight sleeve (129) to limit movement of the airtight sleeve (129) from the retracted position to the advanced position.
A writing instrument according to Claim 1, wherein the projecting rib (17, 139) is generally tri-angular-shaped, and is connected to a central portion of the cap plate (15, 130) so that when the airtight sleeve (9, 129) moves from the advanced position to the retracted position, the cap plate (15, 130) is pivoted in such a direction that the cap plate (15, 130) is pressed against and closes the bore (12, 129a) of the airtight sleeve (9, 129).
A writing instrument according to Claim 1, wherein the projecting rib (17, 139) is elastic so that when the air-tight sleeve (9,129) moves from the advanced position to the retracted position, the cap plate (15, 130) is pivoted in such a direction that the cap plate (15, 130) is pressed against and closes the bore (12, 129a) of the airtight sleeve (9, 129).