Cap for writing instruments containing ink

Abstract: A cap for writing instruments containing ink, having safety ventilation meams enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, the cap being closed on all sides with the exception of an insertion end (4). The 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. The ventilation path being formed by a pair of axial ribs (102) projecting from the outside of the cap and arranged parallel to each other at a distance with an air passage (106) formed therebetween. The ribs (102) are closely spaced to define an air passage therebetween of a mimimum cross-sectional area of 3.4 mm² and have outer side faces (110) tangentially and substantially continuously merging into the peripheral surface of the cap (101).

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 prinicple 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 meams enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, the 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 being formed by a pair of axial ribs projecting from the outside of the cap and arranged parallel to each other at a distance with an air passage formed therebetween, in which said ribs being closely spaced to define an air passage therebetween of a mimimum cross-sectional area of 3.4 mm 2 and having outer side faces tangentially and substantially continuously merging into the peripheral surface of the cap. Accordingly the ventilation path is defined by the channel formed between the ribs. When the cap is swallowed, the windpipe can span across the channel, so that an air passage of a certain mimimum cross-sectional area remains. On the other hand the ribs are not spaced apart from each other at such a distance that there would be a risk that the windpipe could be drawn into the channel which might result in infuries and clogging of the windpipe. Further as another measure to avoid injuries of the windpipe, the outer side faces of the ribs are formed in manner that they circumferentially extend and merge into the surface of the cap in a smooth manner. 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 convential 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 citical, 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 a preferred embodiment and the drawings. In the drawings, identical or similar parts bear the same reference numerals. Figure 1 is a perspective view of a safety cap according to the invention, Figure 2, 3 and 4 show the safety cap according to Figure 1 in general view, plan view and view from the left. The safety cap according to the invention is based on the presence of a pair of ribs on the cap surface extending axially and projecting substantially radially, which ensure that if the cap is swallowed, the windpipe cannot come into contact with its surface along the entire periphery. In the drawings the reference numeral 101 relates to the cap, which is substantially cigar-shaped and whereof the outer diameter normally amounts to no more than 16 mm. The reference numeral 102 relates to a pair of projecting ribs formed on the outer surface of the cap 101, which extend axially along the cap. The open insertion end of the cap 101 bears the reference numeral 104. As illustrated, an outer annular end face may remain between the insertion opening 104 and the facing end of the ribs 102, which end face has an axial length which should not exceed 2 mm. The outer side faces 110 of the pair of ribs 102 extending in parallel one beside the other at a distance apart are shaped so that they pass tangentially or continuously into the outer surface of the cap 101, so that the airway is defined substantially solely by the passage 106 enclosed between the ribs 102. The shaping of the side faces 110 of the ribs reduces the danger of injury to the windpipe or gullet, if the cap 101 is swallowed accidentally. The cap 101 in the present embodiment may have a substantially cylindrical shape. If the cap 101 is fitted to a writing instrument containing ink (not shown), as in the aforedescribed embodiments, the interior of the cap is hermetically sealed and consquently drying-up of the writing point is effectively prevented. If the cap 101 is accidentally swallowed, an axial airway remains between the side faces of the ribs 102. In conjunction with a covering placed around ist, the airway creates a cross-sectional area for the passage of air, which due to suitable dimensions of the ribs 102 is designed such that it amounts to at least 3.4 mm 2 , preferably 6.8 mm 2 at each axial point of the cap 101.

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, the 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-sectional area for ventilation in each radial plane is defined having a throughflow capacity corresponding to the air requirement of a person, said ventilation path being formed by a pair of axial ribs (102) projecting from the outside of the cap and arranged parallel to each other at a distance with an air passage (106) formed therebetween, wherein said ribs (102) are closely spaced to define an air passage therebetween of a mimimum cross-sectional area of 3.4 mm 2 and having outer side faces (110) tangentially and substantially continuously merging into the peripheral surface of the cap (101). A cap according to claim 1, characterized in that the ventilation path terminates at a distance less than or equal to 2 mm from the insertion end (204) of the cap (201).

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