Combination ballpoint pen and mechanical pencil

Abstract

A writing instrument comprising: an elongate hollow housing extending between a first end and a second end, the housing comprising an ergonomic triangular barrel located between first and second end portions, the first and second end portions comprising said first and second ends; wherein the first or second end portions comprise a conical or frustoconical cross-section with inwardly located engagement formations configured for, in a first operable configuration, engaging with a writing cartridge including a ballpoint pen tube container having a writing tip in a first operable configuration, and, in a second operable configuration, engaging with a chuck that chucks a writing lead for a mechanical pencil.

Description

COMBINATION BALLPOINT PEN AND MECHANICAL PENCILTECHNICAL FIELD

[0001] The present invention relates to writing instruments and more specifically it relates to a combination ballpoint pen and mechanical pencil.BACKGROUND

[0002] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[0003] The ballpoint pen was invented in Hungary in 1935 by brothers Lazio and George Biro. Instead of a writing point, the ballpoint pen has a tiny metal ball in the tip of a tube filled with ink. Ink sticks to the ball and the ball rolls the ink onto the paper. Ball-point pen refills comprise a ball-point pen tip which is mounted directly or via a tip holder on the tip of an ink container containing different colors of ink in the ink container or holding balls of different shapes at the tip.

[0004] The ballpoint pen proved to be valuable to pilots, since it worked at high altitudes and did not have to be refilled frequently. In 1945 the Chicago entrepreneur Milton Reynolds introduced the ballpoint pen in the United States. The biggest problem in the development of the ballpoint pen was creating ink of the proper consistency. If the ink was too thin, the pen leaked; if the ink was too thick, the pen clogged. Today, ballpoint pens use a heavy, oil-based ink that flows more slowly than the water-based inks generally used in fountain pens.

[0005] A mechanical pencil is a device that advances the lead so that the pencil never needs sharpening. In some mechanical pencils the lead is inserted in the front end of the pencil, held in place by a slotted cylindrical clamp or an arrangement of jaws, and pushed forward by a rod or cup.

[0006] One of the much-desired features in writing instruments such as mechanical pencils or ball-point pens has been to have a hybrid or dual function ability that would allow the same writing instrument to be used a ball-point pen or a mechanical pencil depending on the specific needs of the end user. Moreover, currently known mechanical pencils have very complex mechanical structures and parts which can greatly add to the cost and complexity of manufacturing.SUMMARY OF INVENTION

[0007] In an aspect, the invention provides a writing instrument comprising: an elongate hollow housing extending between a first end and a second end, the housing comprising an ergonomic triangular barrel located between first and second end portions, the first and second end portions comprising said first and second ends; wherein the first or second end portions comprise a conical or frustoconical cross-section with inwardly located engagement formations configured for, in a first operable configuration, engaging with a writing cartridge including a ballpoint pen tube container having a writing tip in a first operable configuration, and, in a second operable configuration, engaging with a chuck that chucks a writing lead for a mechanical pencil.

[0008] In an embodiment one or more walls defining the triangular barrel comprises an opening for viewing an internal volume of the triangular barrel.

[0009] In an embodiment, each of the three walls defining the triangular barrel comprises the opening, the opening being substantially elongate.

[0010] In an embodiment, the wiring instrument comprising the chuck, the chuck having a frontal split end portion which is split into a plurality of sections, wherein the split end portions of the chuck close and hold the writing lead as the chuck is axially inserted into one of said first of second end portions.

[0011] In an embodiment, an outer engagement portion of the chuck engages with the inner engagement formations provided on the first or second ends to allow the outer engagement portion of the chuck to be received and engaged while holding the writing lead during use.

[0012] In an embodiment, inward axial movement of the chuck results in increased engagement of the outer engagement portion of the chuck with the inner engagement formations of the first or second end portions of the housing resulting in the end portions of the chuck closing and holding the writing lead and wherein outward axial movement of the chuck results in decreased engagement of the outer engagement portion of the chuck with the inner engagement formations of the first or second end portions of the housing resulting in the end portions of the chuck gradually opening and releasing the writing lead.

[0013] In an embodiment, the outer engagement portion of the chuck comprises threads that are configured to inter-engage with complementary threads provided along the inner walls of the first or second end portion of the housing.

[0014] In an embodiment, the frontal end of the chuck comprises a generally convergent configuration.

[0015] In an embodiment, adjacently located sections at the frontal end of the chuck comprise a notch defined by guiding surfaces formed on the adjacently located sections, the guiding surfaces of the notch being configured to receive and engage a key or key portion for separating the sections of the frontal split end portion for releasing and allowing axial advancement of the writing lead through the chuck upon engaging the key within the notch and imparting a twisting movement to the chuck and / or the key.

[0016] In an embodiment, the invention comprises the writing instrument in combination with the key wherein the key comprises a lever with a chuck engaging opening being provided in the key wherein walls defining the key opening comprise key portions that project radially inwardly from the walls wherein the key portions are shaped to be received and engaged with one or more of the notches located in the frontal split portion of the chuck.

[0017] In an embodiment, the writing instrument further comprises a lead sharpener, the lead sharpener being configured to be stowed in a non-use position by engaging with the inwardly located engagement formations configured of the first and / or second end of the housing.

[0018] In an embodiment, the lead sharpener comprises a convergent frontal end portion which protrudes from the first or second end upon engagement of a rear portion of the lead sharpening member with the inwardly located engagement formations configured of the first and / or second end of the housing.

[0019] In an embodiment, the rear portion of the sharpener comprises an opening to receive and position the lead within an internal volume of the rear portion of the lead sharpener.

[0020] In an embodiment, the internal volume of the rear portion comprises a sharpening blade for contacting and sharpening writing lead inserted into the internal volume of the rear portion through the opening of the rear portion.

[0021] In an embodiment, the sharpening blade extends transversely across a longitudinal axis to converge from the opening of the rear portion towards a closed end of the rear portion of the sharpener.

[0022] In an embodiment, the sharpening blade is located along an inner surface of an element of the rear portion that is partially cutout from the outer wall of the rear portion and bent inwardly into the internal volume of the rear portion.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary ofthe Invention in any way. The Detailed Description will make reference to a number of drawings as follows:Figures 1A to 1D show side views of a housing 110 for a writing instrument 100 in accordance with an embodiment.Figures 2A to 2C illustrate sectional views of the writing instrument 100.Figures 3A and 3B illustrate the writing instrument 100 in a first operable configuration (as a ball-point pen).Figures 4A and 4B illustrate the writing instrument 100 in a second operable configuration (as a mechanical pencil).Figures 5A to 5D illustrate several side views of a sharpening member 170 that forms a part of the writing instrument 100 when used in the second configuration.Figures 6A and 6B illustrate isolated perspective views of the sharpening member 170.Figures 6C and 6D illustrate end views of the sharpening member 170.Figures 7A and 7B illustrate sectional views of the sharpening member 170 shown in a first and second in-use configuration.Figure 8A to 8D illustrate side views of the chuck 130 which forms part of the writing instrument 100.Figures 9A and 9B are isolated perspective views of the chuck 130.Figures 9C and 9D are end views of the chuck 130.Figure 10 is a sectional view of the chuck 130 shown in an in-use configuration.Figures 11A to 11 D show the use of a clutch tool 160 that can be used for engaging the chuck 130 to advance the writing tool through the chuck 130.Figure 12 is a top perspective view of the writing instrument 100 in which the chuck 130 is not in engagement with the clutch tool 160.Figure 12A is an enlarged view of the inset shown in Figure 12.Figure 13 is a top perspective view of the writing instrument 100 in which the chuck 130 is in engagement with the clutch tool 160.Figure 13A is an enlarged view of the inset shown in Figure 13.Figure 14A is an enlarged perspective view showing the use of a collar 120 for ensuring engagement of the ball point writing tip of the refill within the first engagement portion 114 of the housing 110.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0024] Figures 1A to 1D illustrate various isolated views of the housing 110 that forms part of the writing instrument generally denoted by100 shown in Figures 1 to 14. The housing 110 is substantially elongate and hollow and is made from machined aluminium. The material used for forming the housing 110 is not limiting. However, as will be evident from the foregoing sections, the configuration of the housing 110 results in the housing 110 being particularly suitable for being made from a single piece of metal that is machined to form the hollow and elongate housing 110 shown in Figures 1A to 1 D. The presently disclosed housing 110 is made from a primary aluminium extrusion process that is followed by CNC machining for machining the various features out of a single piece of extruded aluminium which resulted in unibody construction. The housing 110 comprises an ergonomic triangular barrel 112 (generally triangular cross section with rounded orsmooth corners). The triangular barrel 112 extends for a substantial section of the elongate housing 110 and allows a user to use the “tripod grip” while using the writing instrument. The Tripod Grip is a grip using three fingers of the hand the thumb, index and middle fingers. The Trilobal shape provides improved general finger control and ergonomic comfort while writing. As best shown in Figures 12A and 12B, each of the trilobal flanks including a scalloped or flared end section which assists in preventing the fingers from sliding off the end of the writing instrument housing 110. The trilobal grip has been deliberately extended down the entire length of the writing instrument housing 110 as some uses require distal and proximal grips. Artistic and Sight Sketching for example has a very different grip point to writing or technical sketching.

[0025] The triangular barrel 112 is located between two opposed end portions 114 and 116. Throughout, the specification, these opposed end portions may be referred to as the first and second end portions 114 and 116. The first end 114 generally denotes the writing end of the writing instrument 100 and the second end 116 is the distal end of the writing instrument 100. The triangular barrel portion 112 of the housing 110 generally comprises three side walls and each side walls comprises a respective aperture 118 (three apertures in total) which forms a viewing window that allows the user to be able to see the writing cartridge or writing lead. The longitudinal viewing windows not only provide a viewing window but also reduce weight for the housing 110, improve balance, provide finger traction for rearward based grip applications while also allowing the user to see how much ink or lead is left while using the writing instrument 100.

[0026] The first and second end portions 114 and 116 are substantially frusto-conical and hollow. The first and second end portions 114 include engagement formations 115 and 117 (See Figure 2A) in the form of engagement threads that are provided along the inner walls of the first and second end portions 114 and 116.

[0027] One of the key advantages of the writing instrument 100 described herein is that it can be used as a pen in a first operable configuration and as a mechanical pencil in a second operable configuration. It is envisioned that the writing instrument 100 would be sold as a kit of parts that can be assembled by the user to use the writing instrument as a pen (first configuration) or as a mechanical pencil (second configuration). As will be evident from the foregoing sections, in some embodiments, the writing instrument may be operable to allow the writing instrument to be used in the first and second configurations at the same time.

[0028] Figures 2A to 2C and 3A and 3B illustrate sectional views of the writing instrument 100 whereby the housing 110 is being used as a ball point pen. Figures 2B and 2C illustrate a ball point pen refill cartridge that is being used in combination with the housing 110. The ball point pen refill cartridge B comprises tube container with a writing tip that is engaged with the threaded formations of the first end portion 114 of the housing 110. The refill cartridge B shown in the illustrations is commonly known as the B3 type refill and uses a conical structure B1 that includes the writing tip and a cylindrical structure B2 located adjacent the conical structure B1. The conical structure of the B3 refill protrudes out of the first end portion 114 and the cylindrical portion B2 of the refill engages with the threaded formations of the inner wall of the first end portion 114. The opening defined by the first end portion 114 islarge enough to accommodate the cylindrical part B2 of the writing tip of the refill cartridge but prevents the conical part B1 of the refill B from being received into the first end 114.

[0029] Referring to Figures 14A to 14C a rubber collar 120 may be used for allowing engagement between the writing tip (B1+B2) of the refill B and the first end 114 of the housing 110. Specifically, the collar 120, is made from a resiliently deformable material (such as rubber) and functions as an insert that can be inserted into the opening of the first end 114 of the housing 110 or the second end 116 of the housing 110 and includes a first cylindrical section 122 that has a smaller width and cross section when compared to a second section 124 that has a larger or wider width and defines an opening to receive the writing tip of the refill B. The collar 120 is assembled onto the refill B and then inserted into the housing 110 through the opening at the first end 114. The provision of the collar 120 also provides a shock absorbing function when the writing instrument 100 is used over uneven writing surfaces that involve the use of the writing tip of the refill B being subjected to sudden changes in topography on the writing surface. The rubber collar 120 improves the tolerance fit and ease of assembly between the refill B and the machined internal threads located at the first end 114 or the second end 116. The figures illustrate a B3 insert being suitable for the presently described writing instrument 100. However, other refills may also be used with the writing instrument 100 without departing from the spirit and scope of the invention.

[0030] Figures 4A, 4B illustrate views showing the writing instrument 100 being used a mechanical pencil in the second configuration as previously discussed. In thesecond configuration, a chuck 130 engages with the thread formations provided on the first end 114 and is used for chucking a writing lead. The chuck 130 (isolated views shown in Figures 8, 9 and 10) comprises a frontal split end portion 132 that is split into a plurality of sections that form the split end portion 132. The split end portions 132 close and hold the writing lead (See Figure 10) as the chuck 130 is axially advanced into the first end portion 114 of the housing 110. The chuck 130 comprises a rear portion 134 and a bridging portion 136 that extends between the rear portion 134 and the frontal portion 132. The split sections on the frontal portion 132 extend a least partially into the bridging portion 136. The opening into the first end 114 of the housing 110 comprises an initially larger or broader opening and then converges into a narrower bore that is defined by inner walls with the engagement formations in the form of threads. The bridging portion 136 is generally frusto- coni cal and also comprises split sections that are continuous with the split sections of the frontal end portion 132 of the chuck 130. Gradual axial advancement of the rear portion 134 into the opening at the first end 114 of the housing 110 results in the bridging portion 136 of the chuck 130 passing from a relatively wider opening of the first end 114 into a relatively narrower part of the bore at the first end 114 which results in the split sections of the bridging portion 136 and the frontal portion 132 becoming gradually closed which results in the writing lead being held by the split sections. Similarly, when the chuck 130 is gradually advanced out of the opening at the first end 114 of the housing, the split sections at the frontal portion 132 and the bridging portion open up which allows the writing lead to be advanced through the chuck 130.

[0031] Figures 11 to 13 illustrate several views of a clutch tool 160 for use in conjunction with the writing instrument 100 when used in the second configuration (“pencil”). As shown most clearly in Figures 9A and 9B, adjacently located split sections in the frontal portion 132 of the chuck 130 comprise a notch 133 (three notches) that is defined by guiding surfaces provided by the adjacently located portions of two adjacent split sections of the frontal portion 132 of the chuck 130. The guiding surfaces defining the notch 133 are configured to engage a key portion 162 (See Figures 12A and 12B) of the key 160. Engagement by the key portion 162 of the key 160 and slight twisting of the chuck 130 (while it is fast with the first end 114 of the housing 110) results in the split sections of the chuck 130 opening up that allows the writing lead to be advanced through the chuck. In the preferred embodiment, the clutch tool 160 comprises a lever 160 with the chuck engaging aperture being provided at an end of the clutch tool 160 for engagement with the chuck 130. The provision of the chuck 130 in the aforementioned configuration in combination with clutch tool 160 provides a simple and elegant method of adjusting the writing lead while using the writing instrument 100 in the second configuration. Referring to Figure 10 in particular, inner surfaces of the chuck 130 (which engage directly with the lead) are provided with one or more serrated threaded sections which provide improved gripping of the soft carbon leads.

[0032] Referring to Figures 5 to 7, there is provided a lead sharpener 170 that can be easily stowed in a non-use position by engaging with the inwardly located engagement formations of the second end 116 of the housing 116. As is evident from the figures, the frontal end 172 of the sharpener is exposed in the stowed position and comprises a generally frusto-conical configuration. The rear portion 174comprises the engagement formations and includes an opening 176. Once the lead sharpener 170 is unfastened from the second end 116 of the housing 110, it may be used for sharpening writing leads such as the 0.7mm leads that are commonly sold as refills. The rear portion 174 comprises a sharpening blade member 178 for contacting and sharpening writing lead inserted into the internal volume of the rear portion 174 through the opening 176 of the rear portion 174. The sharpening blade 178 extends transversely across a longitudinal axis to converge from the opening of the rear portion 174 towards a closed end of the rear portion 174 of the sharpener 170. Figures 5B, 6A and 6B illustrate that the sharpening blade 178 is located along an underside of a partially cut-out section 171. The opening 176 into the internal volume of the rear portion 174 of the sharpening member leads into an initially wider bore that converges into a slightly narrower volume. The convergent configuration of the inner part of the rear portion 174 in combination with the transversely arranged blade member 178 allows the user to insert the writing lead into the opening 176 and turning the writing lead in a clockwise or anti-clockwise direction. As shown in Figures 7A and 7B, the transversely arranged blade member 178 gradually shaves the surface of the writing lead portion that contacts the blade and to shape the tip of the writing lead into a generally pointed conical shape.

[0033] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term “comprises” and its variations, such as “comprising” and “comprised of” is used throughout in an inclusive sense and not to the exclusion of any additional features.

[0034] It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[0035] The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

CLAIMS1. A writing instrument comprising: an elongate hollow housing extending between a first end and a second end, the housing comprising an ergonomic triangular barrel located between first and second end portions, the first and second end portions comprising said first and second ends; wherein the first or second end portions comprise a conical or frustoconical cross-section with inwardly located engagement formations configured for, in a first operable configuration, engaging with a writing cartridge including a ballpoint pen tube container having a writing tip in a first operable configuration, and, in a second operable configuration, engaging with a chuck that chucks a writing lead for a mechanical pencil.

2. A writing instrument in accordance with any one of the preceding claims wherein one or more walls defining the triangular barrel comprises an opening for viewing an internal volume of the triangular barrel.

3. A writing instrument in accordance with claim 2 wherein each of the three walls defining the triangular barrel comprises the opening, the opening being substantially elongate.

4. A writing instrument in accordance with any one of the preceding claims further comprising the chuck, the chuck having a frontal split end portion which is split into a plurality of sections, wherein the split end portions of thechuck close and hold the writing lead as the chuck is axially inserted into one of said first of second end portions.

5. A writing instrument in accordance with claim 4 wherein an outer engagement portion of the chuck engages with the inner engagement formations provided on the first or second ends to allow the outer engagement portion of the chuck to be received and engaged while holding the writing lead during use.

6. A writing instrument in accordance with claim 5 wherein inward axial movement of the chuck results in increased engagement of the outer engagement portion of the chuck with the inner engagement formations of the first or second end portions of the housing resulting in the end portions of the chuck closing and holding the writing lead and wherein outward axial movement of the chuck results in decreased engagement of the outer engagement portion of the chuck with the inner engagement formations of the first or second end portions of the housing resulting in the end portions of the chuck gradually opening and releasing the writing lead.

7. A writing instrument in accordance with any one of the preceding claims 4 to 8 wherein the outer engagement portion of the chuck comprises threads that are configured to inter-engage with complementary threads provided along the inner walls of the first or second end portion of the housing.

8. A writing instrument in accordance with any one of the preceding claims 4 to 8 wherein the frontal end of the chuck comprises a generally convergent configuration.

9. A writing instrument in accordance with any one of claims 4 to 8 wherein adjacently located sections at the frontal end of the chuck comprise a notch defined by guiding surfaces formed on the adjacently located sections, the guiding surfaces of the notch being configured to receive and engage a key or key portion for separating the sections of the frontal split end portion for releasing and allowing axial advancement of the writing lead through the chuck upon engaging the key within the notch and imparting a twisting movement to the chuck and / or the key.

10. A writing instrument in accordance with claim 9 in combination with the key wherein the key comprises a lever with a chuck engaging opening being provided in the key wherein walls defining the key opening comprise key portions that project radially inwardly from the walls wherein the key portions are shaped to be received and engaged with one or more of the notches located in the frontal split portion of the chuck.

11. A writing instrument in accordance with any one of the preceding claims further comprising a lead sharpener, the lead sharpener being configured to be stowed in a non-use position by engaging with the inwardly located engagement formations configured of the first and / or second end of the housing.

12. A writing instrument in accordance with claim 11 wherein the lead sharpener comprises a convergent frontal end portion which protrudes from the first or second end upon engagement of a rear portion of the lead sharpening member with the inwardly located engagement formations configured of the first and / or second end of the housing.

13. A writing instrument in accordance with claim 12 wherein the rear portion of the sharpener comprises an opening to receive and position the lead within an internal volume of the rear portion of the lead sharpener.

14. A writing instrument in accordance with claim 12 or claim 13 wherein the internal volume of the rear portion comprises a sharpening blade for contacting and sharpening writing lead inserted into the internal volume of the rear portion through the opening of the rear portion.

15. A writing instrument in accordance with claim 14 wherein the sharpening blade extends transversely across a longitudinal axis to converge from the opening of the rear portion towards a closed end of the rear portion of the sharpener.

16. A writing instrument in accordance with claim 14 or claim 15 wherein the sharpening blade is located along an inner surface of an element of the rear portion that is partially cutout from the outer wall of the rear portion and bent inwardly into the internal volume of the rear portion.

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