Cap for writing instruments containing ink

Abstract: Cap for writing instruments containing ink. The cap (1) is closed on all sides apart from an open insertion end (4) and comprises a safety ventilation device, which allows a flow of air along the cap (1), if the latter has lodged in a child's windpipe when swallowed accidentally. The safety ventilation device comprises an axial ventilation path (3, 6) on the outside of the cap, which along at least one part of its axial extent has an open cross-sectional configuration, so that a covering placed around the cap (1), corresponding to the windpipe, is prevented from pressing along the entire periphery of the cap (1) against its surface. On the contrary, at any axial point of the cap (1), a free cross-sectional area remains for the ventilation with a throughflow capacity which corresponds to the air requirement of a person. The ventilation path may comprise an axial perforation (3) in the base region (12) of a retaining clip (2) and the gap (6) between the retaining clip (2) and outer surface of the cap (1). It may also be formed by ribs extending axially and projecting radially from the outer surface of the cap (1) or by axial grooves in the surface of the cap. The cap (1) effectively prevents drying up of the tip (10) of the writing instrument (8) supplying ink.

Description: The invention relates generally to an improvement to caps for writing instruments containing ink and in particular to a cap with a safety ventilation device in order to facilitate an air flow along the cap, if the latter has lodged in a person's windpipe, for example of a child, when swallowed accidentally. In writing instruments which contain no ink, such as pencils and the like, hitherto in order to prevent asphyxiation as a result of accidental swallowing, an opening may be provided in the top of the cap covering the point of the pencil, so that if the cap has lodged in a child's windpipe, air for breathing may continue to flow through the cap, until medical assistance is given (see for example JP-A-39592/1986 and 118038/1977). A transfer of this principle to a cap for writing instruments containing ink, in which an evaporation of the ink must be prevented and the writing tip must be kept continuously moist, is not readily possible, since due to this the function of the writing instrument is jeopardised. In caps which serve to seal the writing tip of writing instruments containing ink with respect to atmospheric air, the risk of asphyxiation therefore exists in the case of accidental swallowing, such as is to be feared in particular with children. Inter alia this risk has been expressed in a specification of the "British Standard Institution", which is under preparation and dated June 23rd 1989, document No. 89/38201. It has already been proposed (see EP-A-0204252, JP-A-11016/1986), to provide an airway in the cap, which however is sealed hermetically when the cap is fitted to the writing instrument. It is typical of this type of safety caps that one or more perforations are provided at one or more axial or peripheral portions of the cap wall, which perforations thus facilitate an exchange of air between the outside and inside of the cap. One drawback of this solution is the complicated arrangement for achieving a sufficiently tight encapsulation of the tip of the writing instrument, when the cap is fitted. It is also known (DE-A-3728896), to provide a separate tubular air passage with open axial ends and a cross-section closed peripherally all round, on the outside of the cap, in order to separate the safety function from the sealing function. This solution is not solely disadvantageous as regards the manufacturing difficulties connected therewith, but in addition conceals the risk that in the course of time the air passage is easily blocked by foreign bodies which have penetrated, such as food residues, dirt deposits and the like and therefore the safety function can be lost. According to EP-A-395 797 which falls under Art. 54(3)EPC the ventilation path can be formed by a pair of axial ribs on the outside of the cap, which are in a distance from each other which is greater than the diameter of the cap body. From EP-A-319 311 a safety cap is known which has also an axially extending ventilation path on the outside of the cap underneath a clip which is connected to the cap in a rigid, non-resilient manner. It is an object of the present invention to provide an improved safety cap having a simple construction, which prevents drying up of the writing part of writing instruments containing ink in an effective manner, and has improved safety properties to guarantee with a minimum risk of injuries of a person who swallowed the cap, sufficient air for breathing to flow along the cap. According to the invention this problem is solved by a cap for a writing instrument containing ink, having safety ventilation means enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, said cap being closed on all sides with the exception of an insertion end, said safety ventilation means comprising at least one axial ventilation path on the outside of the cap, which along at least part of its axial extension has an open cross-sectional configuration, whereby when a covering is placed around the cap, a cross-sectionl area for ventilation in each radial plane is defined having a throughflow capacity corresponding to the air requirement of a person, said ventilation path comprising a space between a substantially plate-like retaining clip and the outer surface of the cap, said retaining clip being attached adjacent the closed axial end to the cap, in which the spring deflection of said clip being limited by a stop for maintaining a minimum spacing with respect to the cap, said clip in its base portion has a perforation aligned substantially axially to and communicating with said space between the retaining clip and the outer surface of the cap, in which a pair of web-like portions formed by said perforation in the base portion of the retaining clip resiliently connecting the clip to the cap. If a cap of this structure is swallowed in a position with the open insertion end ahead the clip may spread which effectively prevents the cap from further movement in the windpipe. The resilient connecting webs in the base portion also contribute to preventing injuries to the windpipe or gullet. A feature of the caps according to the present invention is the high sealing function resulting from the fact that the caps are closed on all sides, i.e. there are no perforations leading into the inside of the caps. The caps therefore corresponds in their sealing function to conventional caps used in writing instruments without a safety ventilation device. Existing caps can therefore readily be replaced by safety caps according to the invention. The construction of the safety ventilation device according to the invention has advantages both as regards manufacturing techniques, since it is not necessary to form any cavities which are not easily accessible, as well as an improved safety function, in that the portions of the caps, which are critical, can readily be checked at a glance as regards their functional state. A further advantage is the relatively high freedom as regards the design of the caps. The invention will be described in detail hereafter with reference to embodiments and the drawings. In the drawings, identical or similar parts bear the same reference numerals. Figure 1 is a longitudinal sectional view of a safety cap according to a first embodiment of the invention with an associated writing intrument in fragmentary view, Figures 2, 3 and 4 show the safety cap according to Figure 1 in general view, plan view and view from the left, Figure 5 is a longitudinal sectional view of a safety cap according to a second embodiment of the invention with an associated writing instrument in fragmentary view, Figures 6, 7, 8 show the safety cap according to Figure 5 in general view, plan view and view from the left, Figure 9 is a longitudinal sectional view of a safety cap according to a third embodiment of the invention, Figures 10, 11, 12 show the safety cap according to Figure 9 in general view, plan view and view from the left, Hereafter reference will be made to Figures 1 to 12, which show the first to third embodiments of the invention. In Figures 1 to 4, in which the first embodiment of the invention is illustrated, the cap bears the general reference numeral 1. The cap 1 has a substantially tubular or cylindrical shape with an outer diameter of normally up to 16 mm. The cap is closed at one axial end, whereas the other axial end is provided with an insertion opening 4. The writing part 9 of the writing instrument 8 supporting the writing point 10 is inserted by way of the insertion opening 4. A retaining clip 2 extending coaxially to the cap 1 is attached by its base region 12 to the closed top of the cap 1. As shown, the base region 12 may be curved and contains a perforation 3 aligned substantially axially. The airway of the present embodiment comprises the perforation 3 and the gap 6 connected thereto between the retaining clip 2 and the outer surface of the cap 1. The airway should have a cross-sectional area of at least 3.4 mm 2 , preferably greater equal to 6.8 mm 2 , at any axial point along the cap. The retaining clip 2 extends along the outside of the cap 1 as far as a point close to the insertion opening 4. In order that an adequate airway is guaranteed between the edge of the insertion opening 4 and the free end of the retaining clip 2, the spacing m of the free axial end of the retaining clip 2 from the insertion opening 4 should amount to less than 2 mm. The reference numeral 5 relates to the inside of the cap, which when the writing part 9 is inserted, is sealed with respect to the atmosphere by a peripheral region of the writing instrument 8. The reference numerals 13 relate to web-like areas, which are formed by the perforation 3 provided in the base attachment region 12 of the retaining clip 2 and which connect the retaining clip 2 resiliently to the cap. The cap 1 with the inserted writing instrument 8 can be clipped to an article of clothing by means of the retaining clip 2. If a child accidentally swallows the aforedescribed cap 1, then even if the cap penetrates the child's windpipe and becomes lodged there, the perforation 3 in the base attachment region 12 and the gap 6 between the retaining clip 2 and outer surface of the cap 1 form an airway, so that the air passage necessary for the child to breathe is ensured and the danger of asphyxiation does not exist. Furthermore, since the retaining clip extends close up to the insertion opening 4 of the cap, even close to this end of the cap, the airway is not closed by the windpipe. Since the retaining clip is held resiliently by the connecting webs 13, even in the case of contact of the tip of the retaining clip 2 with the gullet or windpipe, the danger of asphyxiation is substantially reduced. The reference numeral 7 relates to a projection, which keeps the retaining clip at a suitable distance from the surface of the cap 1. The second embodiment of the invention is illustrated in Figures 5 to 8. The difference from the embodiment according to Figures 1 to 4 consists in that the retaining clip 2 is attached by way of a radial base attachment region 12 to the top of the cap 1. The retaining clip 2 extends along the cap 1. Provided in the attachment base region 12 of the retaining clip 2 is an axial perforation 3, which is in axial alignment with the gap 6 between the retaining clip 2 and outer side of the cap, so that an airway is formed, which extends as far as the insertion opening 4 of the cap 1. As in the aforementioned embodiment, resilient connecting webs 13 are formed in the base attachment region 12 of the retaining clip 2 on both sides of the perforation 3, which connecting webs facilitate clipping of the cap to air article of clothing and at the same time alleviate the danger of injury to the windpipe, if the cap is accidentally swallowed. Reference can be made to the aforedescribed embodiment for further details. The third embodiment of the invention is illustrated in Figures 9 to 12. This embodiment differs from the embodiment according to Figures 5 to 8 substantially solely in that between the gap 6 and the perforation 3 in the base attachment region 12, an enlarged air space 14 is provided at the top of the cap 1. The perforation 3 can consequently be offset somewhat radially with respect to the gap 6. The resilient connecting webs 13 are provided in the base region 12 at the sides of the perforation 3.

Claims: A cap for writing instruments containing ink, having safety ventilation means enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, said cap being closed on all sides with the exception of an insertion end (4), said safety ventilation means comprising at least one axial ventilation path on the outside of the cap, which along at least part of its axial extension has an open cross-sectional configuration, whereby when a covering is placed around the cap, a cross-sectionl area for ventilation in each radial plane is defined having a throughflow capacity corresponding to the air requirement of a person, said ventilation path comprising a space (6) between a substantially plate-like retaining clip (2) and the outer surface of the cap (1), said retaining clip (2) being attached adjacent the closed axial end to the cap, in which the spring deflection of said clip being limited by a stop (7) for maintaining a minimum spacing with respect to the cap, said clip in its base portion (12) has a perforation (3) aligned substantially axially and communicating with said space (6) between the retaining clip (2) and the outer surface of the cap (1), characterized by a pair of web-like portions (13) formed by said perforation (3) in the base portion (12) of the retaining clip (2) for resiliently connecting the clip to the cap. A cap according to Claim 1, characterized in that the free end of the retaining clip (2) is located on or at a short distance from the insertion end (4) of the of the cap (1). A cap according to claim 1 or 2, characterized in that the cross-sectional area of the ventilation path at any axial position of the cap (1) is greater than or equal to 3.4 mm 2 .

Inventors: KATAMI KAZUNORI, SUZUKI KAZUHIKO, KATAMI, KAZUNORI, SUZUKI, KAZUHIKO
Applicants: TOMBOW PENCIL, TOMBOW PENCIL CO., LTD.
Application year: 1990
Main classification: B43K23
IPC codes: B43K23