Cap for writing instruments containing ink

Abstract: A cap for writing instruments containing ink, has a safety ventilation function in that it enables an air flow along the cap (201), if the cap has lodged in a person's windpipe when swallowed accidentally. The cap (201) is closed on all sides with the exception of its insertion end (204). At least one axial ventilation path is formed by a plurality of axial indentations or grooves (206) formed in the outer surface of the cap and spaced apart peripherally, and a substantially plate-like retaining clip (202) provided between an adjacent pair of axial indentations or grooves (206). Accordingly the ventilation path along 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.

Description: The invention relates 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. In caps which serve to seal the writing tip of a writing instrument 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 been proposed (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 points of the cap wall, which perforations thus facilitate an exchange of air between the outside and inside of the cap. 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. From EP-A-319 311 a safety cap is known which has an axially extending ventilation path on the outside of the cap provided underneath a clip which is connected to the cap in a rigid, non-resilient manner. Finally from DE-U-8908065 a cap is known in which a ventilation path is defined by a number of longitudinal grooves provided between ribs axially extending on the outside of the cap, in which the grooves communicate with the interior of the cap along a body portion thereof near the insertion end. From the view point of an effective protection of the writing part of a writing instrument against drying up the interior of the cap, except for its insertion end, shall be hermetically closed all around. Accordingly it is an object of the present invention to provide an improved safety cap which while having a simple construction prevents drying up of the writing part of writing instruments containing ink in an effective manner, and has improved safety properties to guarantee sufficient air for breathing to flow along the cap. According to the invention this problem is solved by a cap for writing instruments containing ink, having a safety ventilation means enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, said safety ventilation means comprising an 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 partially formed by a plurality of axial indentations or grooves formed in the outer surface of the cap and spaced apart peripherally, wherein the cap being closed on all sides with the exception of its insertion end, in which a substantially plate-like retaining clip being provided between an adjacent pair of said axial indentations or grooves. A cap according to the present invention has a high sealing function resulting from the fact that the cap is closed on all sides, i.e. there are no perforations leading into the inside of the caps at any location of the cap body. The cap therefore corresponds in its sealing function to conventional caps used in writing instruments without a safety ventilation device. Existing caps can therefore readily be replaced by a safety cap 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 cavities or perforations in the cap body as well as an improved safety function, in that the combination of a clip between a pair of indentations or grooves on the outside of the cap results in a longitudinal ventilation path which is more effective than a ventilation path provided by such indentations or grooves alone. Further the portions of the cap, which are critical with regard to the safety function, can readily be checked at a glance as regards their present state. The invention will be described in detail hereafter with reference to an embodiment and the drawings. In the drawings: Figure 1 is a longitudinal sectional view of a safety cap according to an embodiment of the invention, and Figures 2, 3 and 4 show the safety cap according to Figure 1 in general view, plan view and view from the left. In Figures 1 to 4 the reference numeral 201 relates to a substantially cylindrical cap with a closed axial top end and an open insertion end bearing the reference numeral 204. The outer diameter of the cap 201 normally amounts to no more than 16 mm. Attached close to the top end of the cap 201 is a retaining clip 202, which is held by way of a projection 207 formed on the surface of the cap 201, at a suitable distance from the surface of the cap 201. Thus the writing part of a writing instrument (not shown) if inserted through the insertion end 204 in the interior of the cap 201 can be hermetically sealed against the outside. If desired, there may be provided within the cap 201 an additional inner cap for receiving the front part of the writing instrument. The reference numeral 206 relates to a number of indentations or grooves formed in the outer surface of the cap 201, which extend along the cap from its top end to the insertion end 204 and are distributed peripherally at a suitable distance from each other. The free end of the retaining clip 2 may terminate at a distance m from the insertion end 204, which distance should be not more than 2 mm. A covering H placed around the cap 201 is indicated by the broken line in Figure 4. The covering H corresponds substantially to a windpipe in the region of a swallowed cap 201. As shown in Figure 4, axial air paths are formed between the covering H and the grooves or indentations 206, through which air for breathing can flow, because at these portions a direct contact of the covering H or the windpipe with the surface of the cap 201 is prevented. A pair of indentations or grooves 206 is provided adjacent the retaining clip 202 laterally. The area 206 defined by the retaining clip 202, the surface of the cap 201 and the covering H provides an enlarged air passage near the retaining clip 202 for ventilation. The cross-sectional area available as a whole for the ventilation in a radial plane of the cap needs not to be the same along the cap between the axial ends thereof. It is important that a cross-sectional area for the ventilation is available at each axial position of the cap which has a throughflow capacity corresponding at least to the minimum air requirement of a person. Experiments have shown that a minimum cross-sectional area would be 3.4 mm 2 , preferably 6.8 mm 2 . Furthermore it is important that the axial air paths on the outside of the cap have axial open ends which cannot be clogged by a covering H placed around them, respectively by the windpipe of a person.

Claims: A cap for writing instruments containing ink, having a safety ventilation means enabling an air flow along the cap, if the cap has lodged in a person's windpipe when swallowed accidentally, said safety ventilation means comprising an 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 partially formed by a plurality of axial indentations or grooves (206) formed in the outer surface of the cap and spaced apart peripherally, characterized in that the cap being closed on all sides with the exception of its insertion end (204), in which a substantially plate-like retaining clip (202) is provided between an adjacent pair of said axial indentations or grooves (206). A cap according to claim 1, characterized in that the cross-sectional area of the ventilation path at any axial position of the cap (201) is greater than or equal to 3.4 mm 2 . A cap according to claim 1 or 2, 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