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(11) | EP 1 221 383 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Expandable writing instrument |
| (57) An expandable pen (50) has a pen barrel with an expanding middle section. The pen
barrel holds a retractable ball point pen refill cartridge (65). When the pen is expanded,
the writing tip (60) of the refill is extended from a retracted position inside the
pen barrel to a writing position, while the barrel becomes full length for comfort
when writing. The pen may be collapsed for storage, which simultaneously retracts
the writing tip (60) inside the pen barrel. |
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the field of writing instruments and in particular to a new and useful mechanism for expanding the length of a writing instrument barrel while extending a writing tip from a retracted position in the barrel to a writing position.
[0002] Compact devices of all types are sometimes preferred over full-size versions because they occupy less space. However, some compact devices are not as useful as full-sized versions of the same product for a variety of reasons.
[0003] In the case of writing instruments, a small or reduced size pen can be difficult to hold and use for many people, including the elderly, children, the infirm, and people with large fingers. At the same time, a pen or pencil which occupies less space is more easily carried in a pocket or purse.
[0004] Sometimes, pens and pencils are sized to fit with other products they are used with, such as a miniature pen provided with a date planner or a golf pencil stored on the steering wheel of a golf cart. These smaller pens and pencils are non-refillable and must be discarded when the ink or lead is used up. While these writing instruments are a compact, convenient size for storing, they are not as, comfortably for writing with and suffer the problem that they can be difficult for some persons to use.
[0005] Telescoping writing instruments having spiral grooves and followers in overlapping body sections have been produced by the A. T. Cross Company as early as 1875. These writing instruments have at least three movable body sections which move both rotatably and longitudinally relative to each other to either increase or decrease the length of the writing instrument. Follower pins in one section correspond to a spiral groove in another section, so that pulling the ends of the writing instrument cause the middle section to rotate while the instrument lengthens and the writing tip is exposed.
[0006] In a copending U.S. patent application, serial no. 09/688,659 filed October 16, 2000, having some common inventorship, an expandable pen having a cam mechanism for extending the writing tip when front and cap pen sections are pulled apart is disclosed. The cam is activated by the sliding longitudinal movement of the cap section away from the front section on the pen body.
[0007] Other attempts to provide pens having extendable bodies, include a miniaturized ball point pen which is expandable to a more comfortable length for use as disclosed in U.S. Patent 3,174,461. The pen point is always exposed and does not retract within the body of the pen. The body expands by simply sliding two concentric overlapping sections apart. The overlapping sections are frictionally fit to each other. A lower section secures the ball point and ink supply inside the body. The upper section slides inside the lower section and has a tapered end which catches the top of the ink supply to prevent the upper section from being completely separated from the lower section. A cap fits over the upper section and its lower edge stops against the upper edge of the lower section.
[0008] U.S. Patent 3,709,620 teaches a ball point pen having a body which is expandable for use as a pointer. The pen body is formed by a series of telescoping tubes which support and contain the ball point and ink supply. The ball point may be extended or retracted from the pen body by a spring-loaded operation button at the top end of the body. The button has a horizontal channel with a spring-loaded slider having a tab which is forced into an opening in the side of the upper tube when the button is depressed to hold the button and keep the pen tip extended. Pressing the top end of a clip mounted outside the upper tube over the tab pushes the tab and slider back within the button, releasing the button from the depressed position. The button spring may then force the button back upward, retracting the pen tip.
[0009] While the pen tip may be retracted in this pen, it requires a relatively complex arrangement of springs and sliders and it requires the presence of a clip. The extension/retraction mechanism for the pen tip is not integrated with the expansion for the device either. The pen tip cannot be extended outside the pen point when the tubes are expanded for use as a pointer.
[0010] A folding ball point pen is disclosed by U.S. Patent 5,061,104. The pen is hinged near the center of the pen and a recess is provided in the upper section, so that the lower section containing the pen point and ink reservoir may be folded flush into the side of the upper section. The pen point is not retractable.
[0011] These prior pens suffer from the problem that either the pen tip is always exposed, which either requires the use of a pen cap, or there is the risk of accidental marks. The pen is not replaceable; once the ink is used up, the device must simply be thrown away and replaced in its entirety.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide a writing instrument which can be easily expanded from a compact storage size to a longer writing size.
[0013] It is a further object of the invention to provide a writing instrument which includes an internal mechanism for extending and retracting a writing tip when the writing instrument is expanded from a compact storage size to a full-size position for use.
[0014] Accordingly, an expandable pen is provided with a pen barrel having a cap section which slides longitudinally from a closed position covering a middle section to an elongated use position in which the middle section is exposed. The pen barrel holds a retractable pen refill cartridge. When the pen is expanded, the writing tip of the refill is extended from a retracted position inside the pen barrel to a writing position, while the barrel becomes full length for comfort when writing.
[0015] The pen has a front section secured to a pen body with a cap liner which slidably fits over the pen body and mates with the front section when the pen is in the compacted state. A decorative cap may be placed over the cap liner to enclose the end of the pen and form a cap section. The refill cartridge fits within a chamber defined by the front section, pen body and cap liner and is held at a pen point end by a coil spring. A gear is mounted on the pen body and has two sets of teeth which engage a track in the cap liner and a second track on a plunger positioned over the end of the refill cartridge. When the cap section is slid backwards away from the front section, the gear rotates between the track and the scaled track. The different size teeth on the gear scale the sliding movement of the cap section and translate it to a smaller movement for the plunger to force the cartridge downward and the coil spring to compress so the writing tip is exposed. The writing tip on the cartridge is thus extended for use, while the length of the pen is expanded for more comfortable writing.
[0016] The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the drawings:
- Fig. 1
- is a sectional left side elevational view of a writing instrument according to the invention in a use or open position;
- Fig. 2
- is a sectional right side elevational view of the writing instrument of Fig. 1 in a closed or storage position;
- Fig. 3
- is a sectional top plan view of the writing instrument of Fig. 1;
- Fig. 4
- is a front, side, end perspective view of a refill plunger used in the writing instrument of Fig. 1; and
- Fig. 5
- is a side elevational view of a gear used in the writing instrument of Fig. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring now to the drawings, in which like reference numerals are used to refer to the same or similar elements, Fig. 1 shows a writing instrument according to the invention in the form of an expandable ball point pen 50. As seen in Fig. 1, the pen 50 is in an expanded, use position with writing tip 10 of pen refill 65 extended through pen point 60. Pen refill 65 compresses spring 15 against the inside of the front section 20 when the writing tip 60 is extended. Pen body 40 is secured to front section 20 via a threaded connection 45 at one end. A cap liner 30 is slidably mounted over pen body 40 at the other end. The cap liner 30 is preferably covered by a decorative cap (not shown) or formed as an integrated piece. The cap liner 30 only is shown for convenience, but it should be understood that any reference to the cap liner 30 herein may refer to a unitary cap having the same features or to a combined cap and cap liner.
[0019] The front section 20, pen body 40, pen point 60, and cap liner 30 define a chamber for holding the refill cartridge 65. The coil spring 15 supports the bottom end of the refill cartridge 65 against the upper edge of the pen point 60 inside the front section 20. The spring 15 tends to force the refill cartridge 65 away from the pen point 60 and keep it in a retracted position when the pen 50 is collapsed.
[0020] The cap liner 30 is slidably mounted on the pen body 40 so that the cap liner 30 can move between the closed and expanded positions without completely separating from the pen body 40. A gear 70 having two sets of teeth 75, 77 with different diameters is rotatably mounted to the end of the pen body 40 between a cap track 35 and a track 95 of a plunger 90.
[0021] In the storage position, shown in Figs. 2 and 3, the front section 20 mates with cap liner 30 to form a compact, generally cylindrical pen 50.
[0022] Figs. 1-3 show the internal connections of the pen 50 components and gear mechanism used to extend and retract refill cartridge 65 when the pen 50 is expanded and collapsed.
[0023] A slide stop tab 32 on the cap liner 30 mates with corresponding stop slots 47, 48 formed in the pen body 40 to hold the cap liner 30 and cap on the pen body 40 when it is expanded and to help keep the pen 50 in a closed position when stored. The slide stop tab 32 can be disengaged with either slot 47, 48 by pulling or pushing the cap section as needed.
[0025] As seen in Fig. 4, the plunger has track 95 extending from the opposite side of a pushing surface 97. The pushing surface 97 is arranged inside the pen body to press against the end of refill cartridge 65. A pair of guides 92 are provided on the sides of the plunger 90 which correspond to a pair of tracks 43 in the sides of the pen body. The guides 92 prevent the plunger from rotating and changing the position of the plunger track 95 within the pen.
[0026] Fig. 5 illustrates the gear 70 with a set of large diameter teeth 77 which engage the cap track 35 and a set of small diameter teeth 75 which engage the plunger track 95. The two sets of teeth 75, 77 are concentric around gear axle 72.
[0027] Referring again to Figs. 1-3, the gear 70 is seen mounted to the end of pen body 40 by the gear axle 72 held inside axle support channel 42 of the pen body 40. The interaction of the two sets of gear teeth 75, 77 with the two tracks 32, 95 cause the plunger 90 to be forced forward toward the pen tip 60 when the cap section (cap liner 30 and a decorative cap) are pulled back to extend the pen 50 for use from the collapsed position. The plunger 90 in turn presses on refill cartridge 65, forcing it against spring 15 and the writing tip 10 to extend out from the pen tip 60.
[0028] The particular ratio of the diameters of the two sets of gear teeth 75, 77 is determined based on the ratio of the distance the cap section will move to reach the extended position where slide stop 32 mates in slot 48 to the distance the refill cartridge 65 must move to extend the writing tip 10 to a use position. Preferred ranges for the ratio of the larger diameter to the smaller diameter are between 5:1 and 1:1, although the ratio could be greater than 5:1. In a case where a ratio of 1:1 is acceptable for use, the gear may have a single set of gear teeth engaging both tracks.
[0029] To collapse the pen 50 from the writing position, the cap liner 30 is pushed toward the pen tip 60 until stop tab 32 disengages from slot 48 and begins to slide closed. As the cap liner 30 slides back to the closed position, the gear 70 rotates in the reverse direction, causing the plunger 90 to move away from the pen tip 60 and removing pressure from the end of the refill cartridge 65. The spring 15 then forces the refill cartridge 65 back into the pen body 40 until the cap liner 30 abuts the front section 20 and stop tab 32 is mated in slot 47 to hold the pen 50 closed. The writing tip 10 is then completely retracted into pen tip 60 for storage.
[0030] As an alternative to using spring 15 to force the refill cartridge 65 back into the pen body 40 when the pen 50 is collapsed, the plunger pushing surface 97 could be secured to the end of the refill plunger. The plunger 90 would then pull the refill cartridge 65 into the pen body 40. The plunger 90 could be secured to the refill cartridge 65 by having opening 99 frictionally fit over a tapered end of a refill cartridge 65. Alternatively, the plunger pushing surface could be secured to the end of the refill cartridge 65 using an adhesive.
[0031] To maintain the pen 50, the refill cartridge 65 can be replaced by unscrewing threaded connection 45 between the front section 20 and pen body 40, removing the spent cartridge 65 and replacing it with a new one. The front section 20 and pen body 40 can be rejoined and the pen 50 used as described above.
[0032] Using the pen 50, a compact writing instrument can be quickly expanded to a larger writing position while simultaneously extending the pen tip 10 for use.
[0033] In the event that a disposable version of the pen 50 is desired, the front section 20 and pen body 40 could be fused together as a single piece, rather than connected by a threaded connection. Similarly, the pen point 10 could be formed integral with the front section 20 as a single piece instead of as separate components.
[0034] The use of the term refill cartridge herein is intended to mean any self-contained disposable unit which has both a writing material supply and a marking tip for making a visible mark on paper or other material with the writing material. The refill cartridge may be disposable with the pen, or removable from the pen and replaceable.
1. A writing instrument expandable from a compact storage size to a longer, writing size,
the writing instrument comprising:
a pen body having a front section with a pen point at one end of the pen body and a second end;
a cap slidably mounted to the second end of the pen body, the pen body and cap forming a hollow chamber;
a refill cartridge held longitudinally movable within the hollow chamber, the cartridge having a writing tip at one cartridge end;
gear means for longitudinally moving the refill cartridge toward the pen point within the hollow chamber against the spring to extend the writing tip through the pen point to a marking position when the cap is slid away from the pen point on the pen body to an expanded position.
2. A writing instrument according to claim 1, further comprising stop tab means for releasably
holding the pen body and cap in at least one of the expanded and closed positions.
3. A writing instrument according to claim 2, wherein the gear means comprises a plunger
having a plunger gear track, the plunger contacting the cartridge end opposite the
writing tip, a second gear track on the inside of the cap, and a gear rotatably mounted
inside the chamber and engaged with the plunger gear track and the second gear track.
4. A writing instrument according to claim 3, wherein the gear has two sets of gear teeth,
a first set engaging the plunger track and the second set engaging the cap track.
5. A writing instrument according to claim 4, wherein the ratio of a second diameter
of the second set of gear teeth to a first diameter of the first set of gear teeth
is between 5:1 and 1:1.
6. A writing instrument according to claim 5, further comprising a bias spring engaged
between the refill cartridge and pen point.
7. A writing instrument according to claim 6, wherein the front section is separable
from the pen body.
8. A writing instrument according to claim 6, wherein the refill cartridge is replaceable.
9. A writing instrument according to claim 3, further comprising a bias spring engaged
between the refill cartridge and pen point.
10. A writing instrument according to claim 9, wherein the front section is separable
from the pen body.
11. A writing instrument according to claim 9, wherein the refill cartridge is replaceable.
12. A writing instrument according to claim 1, wherein the gear means comprises a plunger
having a plunger gear track, the plunger contacting the cartridge end opposite the
writing tip, a second gear track on the inside of the cap, and a gear rotatably mounted
inside the chamber and. engaged with the plunger gear track and the second gear track.
13. A writing instrument according to claim 12, wherein the gear is mounted on the pen
body.
14. A writing instrument according to claim 13, wherein the gear has two sets of gear
teeth, a first set engaging the plunger track and the second set engaging the cap
track.
15. A writing instrument according to claim 14, wherein the ratio of a second diameter
of the second set of gear teeth to a first diameter of the first set of gear teeth
is between 5:1 and 1:1.
16. A writing instrument according to claim 15, further comprising a bias spring engaged
between the refill cartridge and pen point.
17. A writing instrument according to claim 14, wherein the front section is separable
from the pen body.
18. A writing instrument according to claim 14, wherein the refill cartridge is replaceable.
19. A writing instrument according to claim 1, wherein the front section is separable
from the pen body.
20. A writing instrument according to claim 1, wherein the refill cartridge is replaceable.