GB2176393A

GB2176393A - Writing or painting instrument

Info

Publication number: GB2176393A
Application number: GB08613005A
Authority: GB
Inventors: Yoshiomi Konose
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1985-05-29
Filing date: 1986-05-29
Publication date: 1986-12-31
Also published as: DE3618077A1; GB2176393B; IT8620594A0; IT1204879B; FR2582583A1; GB8613005D0; FR2582583B1

Abstract

In a writing or painting instrument P employing a cartridge-like inner shaft 8 forming an ink reservoir, the inner shaft 8 is detachably mounted in a tubular outer shaft 1 and is reciprocable therein, and means are provided for preventing inadvertent reverse insertion of the inner shaft 8, so that the internal mechanism of the instrument cannot be damaged by reverse insertion of the inner shaft 8. Said means are constituted by the fact that the inner diameter of the outer shaft 1 gradually reduces between position A and position B, at which position B the inner diameter of the outer shaft 1 becomes equal to the outer diameter of the end portion 16b of the end plug 16. Consequently, if inner shaft 8 is inadvertently reversely inserted into the outer shaft it can not extend beyond position B and the internal mechanism is protected against damage. <IMAGE>

Description

SPECIFICATION Writing or painting instrument This invention relates to a writing or painting instrument provided with a cartridge which is slidably mounted in main body of the instrument which may comprise e.g. a so-called writing brush, i.e., brush-like pen, or a manicure liquid applying instrument.

Hitherto, there have been proposed numerous writing or painting instruments of the general type comprising a main body in which is slidably and detachably or exchangeably mounted a cartridgelike member formed by integrating an ink reservoir our a paint liquid reservoirwith other attachments such as a valve mechanism.

In conventional such writing or painting instruments, experience shows that it is possible inadvertently to insert the cartridge-like member into the main body of the instrument the wrong way round and that other parts of the mechanism located in the main body or the cartridge itself can be damaged in this way.

Viewed from one aspect the invention provides a writing or painting instrument comprising a cartridge-like inner member which is axially reciprocable in an outer tubular shaft of the instrument, wherein means associated with the inner wall of said outer shaft and with said inner member are provided which cooperate to prevent the inner member from being reversely inserted fully into said outer shaft.

In one embodiment the outer diameter of a rear end part of said inner member is slightly larger than the outer diameter of a main body parttheredf, the inner diameter of said outer shaft being larger than the outer diameter of said rear end part of said inner member over a length which is longer as measured from the rear end of the outer shaft than the reciprocating distance of said inner member in use and wherein said inner diameter of said outer shaft gradually reduces towards the front end thereof so as to be equal to the outer diameter of said rear end part of said inner member at a position spaced from the front end of the instrument and becoming smaller than the outer diameter of said rear end part of said inner member whilst remaining larger than the outer diameter of said inner member main body part in the region in front of said position.

In an alternative embodiment the outer diameter of a rear end part of said inner member is slightly larger than the outer diameter of a main body part thereof, and a step portion is provided in the inner wall of said outer shaft at a position spaced from the front end of the instrument, so that the inner diameter of said outer shaft is smaller than the outer diameter of said rear end part of said inner member but is larger than the outer diameter of said inner member main body part in the region in front of said step portion, whilst in the region behind the step portion the inner diameter of the outer shaft is larger than the outer diameter of said rear end part of said inner member to permit said reciprocal movement thereof.

Certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Fig. 1 is a central longitudinal sectional view of an embodiment of a writing instrument in accordance with the present invention; and Fig. 2 is a central longitudinal sectional view of another embodiment of writing instrument.

In Fig. 1, reference character P denotes a brushlike pen, and reference numeral 11 denotes a tubular outer shaft which is threadedly engaged at its front end with a tubular front shaft 2. An ink intake pipe 3 and a plug 4 abutting against a front end surface of the pipe 3 are clamped between a front end of the outer shaft 1 and a step portion provided on the inside of the front shaft 2. A brush-like tip 5 is communicated with the ink intake pipe 3 via an aperture 4a provided in a central portion of the plug 4, and is mounted to the inside of the front shaft 2 and retained therein by means of a tubular holder 6.

A tubular inner member or shaft 8, which is smaller in length and diameter than the outer shaft 1, is axially slidably mounted in the outer shaft 1, in such a way that the outer peripheral wall of the inner shaft 8 is closely spaced from the inner wall of the outer shaft 1 and provides a minimum clearance therebetween.

The inner shaft 8 is of cartridge-like configuration and is separable from and detachably mounted to the outer shaft 1.

A spring support 9 is integrally formed on the inside of the inner shaft 8 adjacent the front end thereof. The inner space behind the spring support 9 of the inner shaft 8 forms the ink reservoir 8a for the pen, the rear end opening of which is closed and sealed by means of an end plug 16. The end plug 16 is provided with a concave portion 1 6a adapted to receive the pen cap 7 during writing, which cap 7 covers the tip 5 during non-use as shown in broken lines in Figure 1. In use, when the cap 7 is engaged with the concave portion 16a of the tail plug 16, by depressing the cap in an axial direction, it is possible to slide the cartridge-like inner shaft 8 axially within the outer shaft 1.

Within the inner shaftS, there is also provided a tubular valve seat 12 which abuts against a step portion provided in a base part of the spring support 9. Afixing sleeve 14 is threadably engaged with the front end of the inner shaft 8 so as to clamp a ringlike packing member 13 between the sleeve 14 and the valve seat 12.

When the cartridge-like inner shaft 8 is inserted into the outer shaft 1 from the rear end thereof, the ink intake pipe 3 extends through the aligned central apertures of the fixing sleeve 14, the packing member 13 and of the valve seat 12 and enters the inner shaft 8, that the rear end of the ink intake pipe 3 engages the front end of a valve stem 11 slidably mounted within the inner shaft 8.

The valve stem 11 is constantly urged forward by means of a coil spring 10 mounted between the spring support 9 and a step portion of the vaive stem 11 itself, so that the valve stem 11 is normally seated on the valve seat 12 to prevent ink contained in the ink reservoir 8a from leaking therefrom. When the inner shaft 8 is mounted in place in the outer shaft 1, by manually depressing the cap 7 the inner shaft 8 may be moved forward so as to release the valve stem 11 from the valve seat 12, whereby ink can leak through the clearance defined between the valve stem 11 and the valve seat 12 and can flow into the ink intake pipe 3 via an opening 3a provided adjacent the rear end thereof and is thus fed to the brush-like tip 5.

When the cap 7 is released the inner shaft 8 returns to its initial position so that the valve stem 11 is again seated on the valve seat 12 to prevent the ink from leaking from the ink reservoir 8a.

When the valve stem 11 is spaced from the valve seat 12 so that ink can leak from the ink reservoir 8a, the packing member 13 is effective to prevent the ink from flowing outward beyond the packing member 13 and thus ensures that the ink flows only into the ink intake pipe 3.

After the cartridge-like inner shaft 8 has been mounted in the outer shaft la a cap 17 having a central circular opening is threadably engaged with the rear end of the outer shaft 1 to hold the inner shaft 8 therewith in.

As shown in Figure 1 the inner shaft is slidable axially in the outer shaft 1 through a distance Ii by manually depressing the cap 7 as aforesaid.

As also shown in Figure 1 the outer diameter of a rear end portion 16b of the end plug 16 engaged with the rear end of the inner shaft 8 is made slightly larger than the outer diameter of the inner shaft 8 whilst the inner diameter of the outer shaft 1 is made slightly larger than the outer diameter of the end portion 16b of the end plug 16 over a length 12, which length 12 as measured from the rear end of the outer shaft 1 toward the front end thereof, i.e., to a position "A", is slightly longer than the distance 11.

The inner diameter of the outer shaft 1 gradually reduces between position A and a position B slightly behind a rear end of the fixing sleeve 14, at which position B the inner diameter of the outer shaft 1 becomes equal to the outer diameter of the end portion 16b of the end plug 16. In the region in front of position B the inner diameter of the outer shaft becomes smaller than the outer diameter of the portion 16b of the end plug 16, whilst remaining larger than the outer diameter of the inner shaft 8.

It should be noted that in Fig. 1 certain dimensions are exaggerated to show the construction of the pen more clearly.

The illustrated embodiment of the invention is so constructed that, when the cartridge-like inner shaft 8 is correctly inserted into the outer shaft 1 from the rear end thereof, the inner shaft 8 can be located in its predetermined position to facilitate reciprocal movement thereof over the required distance 1 within the outer shaft 1.

However, in the event that the cartridge-like inner shaft 8 is inadvertently reversely inserted, i.e. from the wrong end thereof, into the outer shaft 1 the inner shaft 8 can only be inserted into the outer shaft 1 up to the position B and cannot extend beyond such position B, and consequently there is no risk of damaging the fixing element 14 and other parts of inner shaft 8 andlorthe ink pipe 3 by incorrect insertion of the shaft 8. Since the inner shaft 8 can enter only approximately half-way along the outer shaft, the user will immediately notice that the inner shaft 8 has been inserted wrongly.

Fig. 2 shows a further embodiment of the present invention, which embodiment has substantially the same construction as the embodiment shown in Fig.

1 except as regards the inner wall of the outer shaft 1'.

Thus, a step portion 18' is provided in the inner wall of the outer shaft 1' at a position slightly behind the rear end of the fixing sleeve 14, such step 10' making the inner diameter of the outer shaft 1' smaller than the outer diameter of the end portion 16b of the end plug 16' of the inner shaft 8' whilst remaining larger than the outer diameter of the inner shaft 8'. The inner diameter of the outer shaft 1' is however larger than the outer diameter of the end portion 16b' of the end plug 16' in the region thereof behind the step portion 18'.

The embodiment of the present invention shown in Fig. 2 is thus so constructed that when the inner shaft 8' is correctly inserted into the outer shaft 1', reciprocal movement of the inner shaft 8' over the predetermined distance Ii is facilitated. On the other hand, if the inner shaft 8' is reversely inserted into the outer shaft 1' by mistake, the step portion 18' of the outer shaft 1' acts as a stopper, so that the end portion 16b of the end plug 16' is brought into abutting contact with such step portion 18' to prevent the inner shaft 8' from further entering the outer shaft 1' beyond the step portion 18'. As a result, the user can again notice that the inner shaft 8' has been inserted wrongly and damage to the inner shaft andlorto the ink pipe and associated parts is avoided.

Modifications to the instruments described and illustrated herein may be readily apparent to those of relevant skill which retain one or more of the advantages envisaged. The disciosure hereof is intended to encompass such modifications regardless of whether any particular feature or features presently described and/or claimed herein may be omitted.

Claims

1.writing or painting instrument comprising a cartridge-like inner member which is axially reciprocable in an outer tubular shaft of the instrument, wherein means associated with the inner wall of said outer shaft and with said inner member are provided which cooperate to prevent the inner member from being reversely inserted fully into said outer shaft.

2. A writing or painting instrument as claimed in claim 1, wherein the outer diameter of a rear end part of said inner member is slightly larger than the outer diameter of a main body part thereof, the inner diameter of said outer shaft being larger than the outer diameter of said rear end part of said inner member over a length which is longer as measured from the rear end of the outer shaft than the reciprocating distance of said inner member in use and wherein said inner diameter of said outer shaft gradually reduces towards the front end thereof so as to be equal to the outer diameter of said rear end part of said inner member at a position spaced from the front end of the instrument and becoming smaller than the outer diameter of said rear end part of said inner member whilst remaining larger than the outer diameter of said inner member main body part in the region in front of said position.

3. Awriting or painting instrument as claimed in claim 1, wherein the outer diameter of a rear end part of said inner member is slightly larger than the outer diameter of a main body part thereof, and a step portion is provided in the inner wall of said outer shaft at a position spaced from the front end of the instrument, so that the inner diameter of said outer shaft is smaller than the outer diameter of said rear end part of said inner member but is larger than the outer diameter of said inner member main body part in the region in front of said step portion, whilst in the region behind the step portion the inner diameter of the outer shaft is larger than the outer diameter of said rear end part of said inner member to permit said reciprocal movement thereof.

4. A writing or painting instrument substantially as herein described with reference to Figure 1 of the accompanying drawings.

5. A writing or painting instrument substantially as herein described with reference to Figure 2 of the accompanying drawings.