GB2325649A

GB2325649A - Cap with eraser for writing instrument

Info

Publication number: GB2325649A
Application number: GB9708630A
Authority: GB
Inventors: Cheng-Wha Chuang
Original assignee: Pioneer Industrial Corp Taiwan
Current assignee: Pioneer Industrial Corp Taiwan
Priority date: 1997-04-29
Filing date: 1997-04-29
Publication date: 1998-12-02
Also published as: GB9708630D0

Abstract

The cap includes a body portion 20 with a clip 40, an eraser 60 and a removable transparent cover 70, the eraser including differently-coloured portions 62-68.

Description

ERASER-FITTED CAP ASSEMBLY FOR A WRITING INSTRUMENT BACKGROUND OF THE INVENTION Field of the Invention The invention relates generally to an improved apparatus for removably covering an end of a writing instrument and, more particularly, to an eraser-fitted cap assembly for a writing instrument.

Discussion of Related Art It has been known to provide writing instruments such as pencils or erasable ink pens with erasers disposed at the non-writing end thereof, which eraser either are formed integrally with or permanently affixed to the writing instrument or are detachably mounted, such as in the case of a mechanical pencil, so that a fresh eraser can be replaced for a used one or the eraser can be removed to replenish the lead supply of the pencil.

With eraser-fitted mechanical pencils of the prior art especially, the efficiency and durability of the erasers has been limited by both the shape and the dimensions of the eraser assembly. Typically, these erasers are shaped in the form of a post, comprising a generally cylindrical body having a diameter that is significantly less than its length.

It is considered desirable, both for aesthetic and functional reasons, for the diameter of a writing instrument to be substantially uniform or, alternatively, for the portion of the writing instrument with the greatest diameter to be in about the mid-section thereof. When an eraser assembly is provided at the non-writing èndsof fhe pencil, then, the overall diameter of the assembly:usfl'ally will not exceed the diameter of the cylindrical main section of the pencil which contains the lead. Indeed, the maximum diameter of the eraser often must be considerably smaller than that of the main body of the pencil, for example, when the eraser assembly is provided with a metal cap to cover the eraser, as the diameter of the cap commonly is designed not to exceed the diameter of the inner circumference of the pencil main body section.

Due to the limitations on the diameters of known erasers of mechanical pencils, the longer the eraser the less stable it is when applied to paper to perform its intended purpose. Accordingly, the practical dimensions of the eraser are restricted not only by diameter but also by considerations of length. If the aspect ratio of the length of the eraser to the circumference thereof is too great, then the eraser tends to flex and bend more that is desired when it is being used to erase, and it can even snap in two if sufficient care is not exercised.

Obviously, then, if low mass is prerequisite to functionality, such erasers will quickly wear out upon use.

These factors tend to discourage the user from employing the eraser provided with the pencil at all, in favour of some other, stand-alone erasing device.

Accordingly, those concerned with the manufacture of writing instruments long have recognised the need for improved eraser-fitted assemblies to be used with the same, and the present invention fulfils these needs.

SUMMARY OF THE INVENTION Briefly, and in general terms, the present invention provides a new and improved eraser assembly for a writing instrument that enables the eraser to be used with a greater degree of precision than prior art eraser assemblies than heretofore have been used with mechanical pencils or other writing instruments.

A detachable eraser-fitted cap assembly according to the present invention comprises: a generally cylindrical cap body having a proximal end and a distal end characterised by a distal opening; an eraser-retaining member affixed to said proximal end of said cap body having an eraserreceiving element; and an eraser having a base portion adapted to be removably inserted into said eraser-receiving element of said eraser-retaining member; whereby said distal opening of said cap body of the eraser-fitted cap assembly can be temporarily attached to a writing instrument.

Preferred embodiments of the invention provide an eraser that is more reliable and that has better structural integrity and overall quality than anything known in the prior art, and moreover, is aesthetically pleasing. When neither the writing instrument nor the eraser assembly according to the invention are being used, the eraser assembly of the invention further beneficially can cover the writing end of the writing instrument, to protect it from destruction or damage, or in the case of an erasable pen, from drying out.

The eraser-fitted cap assembly of preferred embodiments of the invention generally comprise three elements, a substantially cylindrical cap body, an eraser-retaining member, and an eraser. In a preferred embodiment, a removable cover further is provided to protect the eraser when it is not being used. The eraser is removably inserted into the eraser-retaining member which, in turn, is affixed to the cap body. The assembly then is detachably mounted about the writing end of a writing instrument and can be used to erase material on a writing surface either while resident on the writing instrument or after being detached therefrom. Thus the invention allows a writing instrument to be provided with an eraser than is of sufficient size, strength and durability which permits the eraser to be used efficiently and with ease to perform its intended function. The eraser-fitted cap assembly of the present invention therefore is an improvement over prior art devices insofar as it can be provided with a larger, more stable eraser than has been provided in the non-writing ends of mechanical pencils or pens in the past, and carries the added benefit of offering a means of protecting the writing end of the instrument when it is not being used to write.

The above and other advantages of the invention will become more apparent from the following detailed description when considered in conjunction with the accompanying drawings of exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of an eraser-fitted cap assembly embodying features of the invention; FIG. 2 is an enlarged, longitudinal, cross-sectional view of the eraser-fitted cap assembly of FIG. 1; and FIG. 3 is an enlarged, longitudinal, cross-sectional view of an alternate embodiment of an eraser-fitted cap assembly according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown a preferred embodiment of an eraser-fitted cap assembly 10 in accordance with the invention, comprising a generally cylindrical cap body 20, an eraser-retaining member 50, an eraser 60, and a removable eraser cover 70. For present purposes, the proximal direction is towards the end of the eraser-fitted cap assembly 10 that is intended to cover the writing end of the writing instrument when the cap assembly is fitted onto the writing instrument, and is indicated by the arrow X that is shown on the drawing figures. Correspondingly, the distal direction is away from the end of the eraserfitted cap assembly that is intended to cover the writing end of the writing instrument when the cap assembly is fitted onto the writing instrument, and is indicated by the arrow Y that is shown on the drawing figures. It is noted that, although the most desirable application of the eraser-fitted cap assembly of the invention usually will be to the writing end of a pencil or a pen, it also is contemplated that the assembly sometimes will prove useful when fitted over the non-writing end of a writing instrument that may or may not already be equipped with an eraser of a less efficient or durable design.

The cap body 20 and cover 70 beneficially can be fabricated from plastic, preferably a transparent plastic moulding.

The eraser-retaining member 50 likewise can be formed by moulding it from plastic, which material further can be coloured in any preferable colour. The plastic material, being slightly elastic and thus slightly deformable, will prevent the cap assembly from fracturing when it is applied to erase marks made by the writing instrument with which it is used. The eraser 60 itself, on the other hand, and as is well known to those skilled in the art, is made from a material having a predetermined elasticity, such as rubber or like compounds.

The cylindrical cap body 20 is characterised by an inner surface 22 and an outer surface 24. At the proximal end 26 of the cap body there is defined a proximal opening 28, which is adapted to receive the distal section of the eraser-retaining member 50. There likewise is defined a distal opening 30 in the distal end 32 of the cap body, which allows the eraser-fitted cap assembly to be detachably fitted over the writing end of a writing instrument. In a preferred embodiment, the inner diameter of the proximal end 26 is slightly less than the inner diameter elsewhere along the cap body, thus providing the cap body with a somewhat tapered appearance along a longitudinal axis thereof.

An annular plate 34 is provided near the proximal end of the cap body 20, longitudinally spaced from the proximal opening 28 by a distance which approximates the length of the distal-most element 56 of the eraser-retaining member 50 that is seated in the cap body. The annular plate 34 preferably is formed integrally with the inner surface 22 of the cap body 20, but other suitable techniques of placing the plate will be obvious to one having ordinary skill in the art.

Desirably, the inner surface 22 of the cap body 20 further is provided with a series of raised ribs 36 which, like the annular plate 34, preferably are formed integrally with the inner surface 22. The ribs 36 run along the inner surface 22 in a generally longitudinal axial direction, from the point of attachment of the annular plate 34 to the cap body proximal opening 28. The raised ribs 36 tend to facilitate seating and retention of the eraser-retaining member 50 in the cap body 20.

A flange 38 is disposed about the circumference of the opening 30 at the distal end 32 of the cap body 20 to facilitate the fitting of the eraser-fitted cap assembly 10 over the writing end of the writing instrument when the writing instrument is not in use.

A clip 40 is affixed to the generally cylindrical cap body 20 at a point of attachment 42 on the outer surface 24 thereof, which preferably is located somewhat distally of the longitudinal position of the annular plate 34 in the cap body 20. The clip 40 has a base portion 44 extending distally of the point of attachment 42 and oriented in a direction that is generally parallel to a longitudinal axis of the cap body 20. A protruding portion 46 of the clip 40 is juxtaposed with the base portion 44, and preferably extends for a distance beyond the distal end 32 of the cap body 20. The base portion 44 and the protruding portion 46 of the clip 40 are oriented so as to provide a degree of clearance from the cap body 20, which clearance allows the clip to be employed to conveniently secure the eraser fitted cap assembly 10 to a shirt pocket or pencil or pen case. The clip 40 also desirably prevents the assembly 10 from rolling when it is laid on a writing surface such as a desk or table, whether the assembly then is secured on or detached from the writing instrument with which it is intended to be used.

The eraser-retaining member 50 is comprised of three substantially co-axially disposed, generally cylindrical elements of varying diameters. The retaining ring 52 is the element of the three with the largest diameter, it being formed to accommodate both the eraser-receiving element 54, which has a circumference designed to fit snugly within the inner circumference of the retaining ring, and the engaging element 56, which is inserted into the proximal opening 28 of the cap body 20, so as to adjoin the cap body with the eraser-retaining member 50. The outer diameter of the engaging element 56 can be approximately equal to the diameter of the inner diameter of the cap body 20, to encourage a secure fit when the eraser-retaining member 50 is connected to the cap body 20.

Alternatively, the outer diameter of the engaging element 56 can slightly exceed that of the inner diameter of the cap body 20, so that the consideration between the eraserretaining member and the engaging element can be accomplished by elastic deformation of the engaging element 56 when it is press-fitted into the proximal opening 28 of the cap body 20. Preferably, the retaining ring 52, the eraser-receiving element 54, and the engaging element 56 are formed integrally from a metal or plastic having a strength suitable for holding the eraser 60 stably with respect to the cap body 20, but which is characterised by a resiliency or elasticity sufficient to permit the eraserretaining member 50 to be reliably fitted into and secured in the cap body 20. The connection between the proximal end 28 of the cap body 20 and the engaging element 56 of the eraser-retaining member 50 can be enhanced by adhesively-, chemically- or heat-bonding the engaging element to the proximal end. The retaining ring 52 can be attached to the circumference of the proximal opening 28 of the cap body 20 by similar bonding methods for added security.

The eraser 60 preferably has a diameter approximating the diameter defined by the inner circumference of the eraserreceiving element 54. Because of the predetermined elasticity that characterises the materials or compounds from which erasers typically are formed, it is contemplated that the eraser 60 might be characterised by a diameter that slightly exceeds that which is associated with the inner circumference of the eraser-receiving element 54, such that the eraser is removably fitted into the eraserreceiving element by press-fitting, taking advantage of the elastic and deformable properties of the material from which the eraser is formed.

The eraser-receiving element 54 further is provided with a small diameter orifice 58 which is adapted to receive a pin (not shown in the drawing figures) that optionally can be used to secure the eraser 60 to the element 54. In any event, it is contemplated that the eraser 60 will be removably deployed in the eraser-retaining member 50, permitting replacement of a worn eraser with a fresh eraser when indicated.

Similar to erasers of the prior art that have been fitted into mechanical pencils, the eraser 60 is post-like in appearance, however, the eraser of the eraser-fitted cap assembly according to the invention is characterised by a diameter-to-length aspect ratio that is desirably less than that of the mechanical pencil erasers used in the prior art. Because the eraser-fitted cap assembly of the invention is designed to accommodate erasers exhibiting a diameter that is about equal to or greater than the overall diameter of the cap body 20 or the writing instrument with which it is intended to be used, it can be provided with a length that enhances the longevity of the eraser but which does not concurrently compromise its stability and usefulness.

The eraser 60 has a post-like shape characterised by a generally circular transverse cross-section, although other forms of an eraser are contemplated, such as those having a generally square or rectangular transverse cross-section.

The eraser has a base 62 which is seated in the eraserreceiving element 54 of the eraser-retaining member 50.

The tip 64 of the eraser 60 is generally hemispherical in aspect and protrudes from the eraser-receiving element 54 so as to be usable.

The eraser 60 desirably is uniquely patterned with at least two different colour-tinted portions for aesthetic appeal.

For example, the eraser 60 can be characterised by a pentagonal portion 66, extending through the entire length thereof and in a first colour, such as pink or blue, and by arc-like sections defined by the mass not consumed by the pentagon provided in a contrasting colour, such as white.

The pattern and colour configuration of the eraser is superior to that of standard erasers of uniform appearance and tint insofar as the eraser contemplated for use with an eraser-fitted cap assembly according to the invention will remain attractive to the eye even as it wears through use for its intended purpose.

The removable eraser cover 70 has an upper hemispherical portion 72 designed to accommodate the similarly-shaped tip 64 of the eraser 60. The base portion 74 of the eraser cover 70 has an aperture 76 to allow the eraser to be received in the cover when desired, by removable engagement with the eraser-receiving element 54 of the eraserretaining member 50.

With reference to FIG. 2, it can be seen that in order to detachably mount the eraser-fitted cap assembly 10, the assembly is oriented so that the distal end 32 of the cap body is in line with the writing end 80 of the writing instrument 82 and the writing end is inserted into the opening 30, whereby the flange 38 facilitates the removable engagement of the assembly with the body 84 of the writing instrument and the eraser-fitted cap assembly serves to protect the pencil lead or pen nib 86 and pencil or pen tip 88. As configured, the combination of the eraser-fitted cap assembly and the writing instrument typically are placed in a pencil case to be stored until it is desired to use either the eraser or the pencil or pen.

In use of the eraser-fitted cap assembly of the invention, the eraser 60 is exposed by taking off the removable eraser cover 70, thus permitting the eraser to be applied to the writing surface either while the assembly is attached or detached from the writing instrument 82, the diameter-tolength aspect ratio of the eraser allowing the erasing operation to be performed efficiently and easily, with minimal proportional wear. Even as wear gradually occurs over time through use, the multiple colours and multiple patterns of the eraser characterise it with a pleasant appearance, similar to that of a soccer ball.

An alternate embodiment of an eraser-fitted cap assembly according to the invention can be appreciated by reference to FIG. 3. In this embodiment, the retaining ring 52 of the eraser-retaining member 50 is manufactured integrally with the proximal end 26 of the generally cylindrical cap body 20 as by, for example, a single plastic mould, such that the need for the elements of a retaining ring 52 and an annular plate 34 are eliminated. Consequently, this second embodiment of an eraser-fitted cap assembly is simpler in structure than the first and accordingly can be assembled more easily and manufactured at a lower cost.

It will be apparent from the foregoing that, while the invention has been described herein in terms of certain presently preferred embodiments directed by eraser-fitted capping assemblies for mechanical pencils and pens with erasable ink, those skilled in the art will recognise that the assembly of the invention may be used with a variety of other implements intended for applying marks on a writing surface. For example, in addition to refillable pencils containing leads that are inserted axially into the instrument, the invention will be useful with other pencils with a round or hexagonal shape.

Claims

CLAIMS: 1. A detachable eraser-fitted cap assembly intended to be used with a writing instrument, the eraser-fitted cap assembly comprising: a generally cylindrical cap body having a proximal end and a distal end characterised by a distal opening; an eraser-retaining member affixed to said proximal end of said cap body having an eraser-receiving element; and an eraser having a base portion adapted to be removably inserted into said eraser-receiving element of said eraser-retaining member; whereby said distal opening of said cap body of the eraser-fitted cap assembly can be temporarily attached to a writing instrument.
2. The eraser-fitted assembly of claim 1, wherein a flange is disposed about the said distal opening to facilitate the fitting of the eraser-fitted cap assembly about an end of the writing instrument.
3. The eraser-fitted cap assembly of claim 1, further comprising a removable eraser cover.
4. The eraser-fitted cap assembly of claim 1, wherein said generally cylindrical cap body further is characterised by an inner surface, a proximal opening at said proximal end, and an annular plate disposed in said inner surface of said proximal end, the circumference of said annular plate approximating the circumference of said inner surface, said plate adapted to seat said base portion of said eraser.
5. The eraser-fitted cap assembly of claim 4, wherein said annular plate is formed integrally with said inner surface of said cylindrical cap body.
6. The eraser-filled cap assembly of claim 4, wherein said generally cylindrical cap body further is characterised by a longitudinal axis running axially thereof and by at least one raised rib oriented generally parallel to said longitudinal axis along said inner surface from said annular plate to said proximal end of said cap body, said at least one raised rib aiding in detachably securing said eraser retaining member.
7. The eraser-fitted cap assembly of claim 4, wherein said generally cylindrical cap body further is characterised by an outer surface and a point of attachment thereon for a clip, said point of attachment providing a clearance between said outer surface and said clip, said clip having a base portion extending longitudinally along said cap body toward said distal end thereof and a protruding portion opposed to said base portion that protrudes longitudinally and distally from said cap body.
8. The eraser-fitted cap assembly of claim 1, wherein said eraser-retaining member further comprises a retaining ring having a circumference adapted to snugly surround said eraser-retaining member and which approximates or exceeds the circumference of said cap body.
9. The eraser-fitted cap assembly of claim 4, wherein the said eraser-retaining member further comprises an engaging element having a circumference adapted to snugly fit within said retaining ring and which approximates or slightly exceeds the circumference of said inner surface of said cap body, whereby said engaging element is press- fitted into said proximal opening of said cap body to affix said eraser retaining member thereto.
10. The eraser-fitted cap assembly of claim 9, wherein said eraser-receiving element, said retaining ring and said engaging element are formed integrally from a material from the group comprising metals or plastics.
11. The eraser-fitted cap assembly of claim 1, wherein said eraser-retaining member is formed integrally with said generally cylindrical cap body.
12. The eraser-fitted cap assembly of claim 1, wherein said eraser-receiving element further is characterised by a small diameter orifice adapted to receive a pin to support said eraser.
13. The eraser-fitted cap assembly of claim 1, wherein said eraser is further characterised by a tip portion having a generally hemispherical shape.
14. The eraser-fitted cap assembly of claim 1, wherein said eraser is generally cylindrical in shape and the length of said cylinder is less than twice the diameter of said cylinder.
15. The eraser-fitted cap assembly of claim 1, wherein said eraser is comprised of a uniform material composition that is tinted with more than one colour.
16. The eraser-fitted cap assembly of claim 15, wherein said eraser is comprised of more than one type of material.
17. The eraser-fitted cap assembly of claim 1, wherein said eraser is a comprised of a uniform material composition that is characterised by more than one pattern.
18. The eraser-fitted cap assembly of claim 17, wherein said eraser is comprised of more than one type of material.
19. The eraser-fitted cap assembly of claim 1, wherein said generally cylindrical cap body is manufactured from a plastic material.
20. The eraser-fitted cap assembly of claim 19, wherein said plastic material is transparent.
21. The eraser-fitted cap assembly of claim 19, wherein said eraser-retaining member is manufactured from a plastic material.
22. The eraser-fitted cap assembly of 21, wherein said plastic material of said generally cylindrical cap body and said plastic material of said eraser retaining member is transparent.
23. A detachable eraser-fitted cap assembly intended to be used with a writing instrument, substantially as described with reference to the accompanying drawings.