GB2202429A

GB2202429A - Liquid applicator valve device

Info

Publication number: GB2202429A
Application number: GB08807067A
Authority: GB
Inventors: Yoshiomi Konose
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1987-03-24
Filing date: 1988-03-24
Publication date: 1988-09-28
Anticipated expiration: 2008-03-24
Also published as: GB8807067D0; FR2612843B1; GB2202429B; DE3809985A1; FR2612843A1

Description

NW 52-755 LIQUID APPLICATOR 2202429 The present invention relates to

improvement of a valve device for use in a liquid applicator such as a tool for applying writing ink, liquid cosmetics, liquid medicine, liquid paint and liquid 5 adhesive.

It is already known in the prior art to use a valve device in this type of tool for controlling the supply of liquid between a liquid reservoir and a writing or coating member. A piston means is sometimes provided, in which a valve rod is used as a piston and a spring seat functions as a cylinder.

In a known such valve device, shown in figure 4, an end section 3 at the rear end of a cylinder portion 2 in a spring seat 1 is cut off substantially perpendicular to the axial line. Thus in a device according to the prior art, when piston section 5 of a valve rod 4 is inserted into the cylinder section 2 of the spring seat 1 the pressure in the cylinder portion 2 suddenly and sharply increases and a large amount of liquid is rapidly discharged. If a large volume of liquid is discharged as described above, the liquid often drips from the coating or writing member, which is obviously not advantageous. 25 This invention provides a liquid applicator which can supply liquid at a rate which is more moderate and which increases only gradually, such that dripping of liquid from the coating or writing member is avoided. According to the present invention there is provided a valve device for controlling the supply of liquid from a reservoir to the tip of a writing or coating tool or the like, such device comprising a matingly engaged piston and cylinder 2 1 arranged for relative movement between open and closed conditions of the valve device in use, wherein a tapered liquid flow path is associated with the piston and cylinder thereof which is arranged to be closed gradually as the piston is engaged with the cylinder so as to avoid abrupt increases in liquid pressure downstream of the valve device when the valve is closed.

There are a number of means whereby a tapered flow path can be provided between the piston and cylinder which gradually opens and closes as the piston moves relative to the cylinder. In a preferred embodiment the cylinder is provided with one or more cutaway sections in its circumferential wall at least in the region of an opening whereby the piston enters said cylinder, wherein said cutaway sections are tapered circumferentially. Thus as the piston approaches the openin7 in the rear end of the cylinder the flow path gradually closes due to a gradual decrease in the circumference of the cylinder which is cutaway to allow liquid to flow away from the valve device.

In a second embodiment means whereby said flow path is tapered comprises a radially tapered inner wall of the cylinder. Hence as the piston enters further into the cylinder the radial clearance between the piston and the inner wall is progressively reduced, thus closing the flow path associated therewith.

In a further embodiment the means whereby the flow path is tapered comprises one or more tapered grooves on the inner wall of the cylinder. For example it would be possible to construct grooves in the inner wall of the cylinder which extend along part of the length of the cylinder and which have a maximum depth at the rear face of the cylinder in the region where the piston enters. other arrangements of grooves are possible.

.j L I- - It is also envisaged that the means whereby the flow path is tapered may also include providing the piston with a taper or with grooves in the region of the end thereof which enters the cylinder.

By providing a flow path which is tapered as the piston enters the cylinder a sudden increase of pressure within the cylinder is avoided. Thus a sudden increase in the flow of liquid to the writing or coating member is also avoided. In this way problems encountered with the prior art devices in the form of liquid dripping from the writing or coating members are avoided.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings wherein:- Fig. 1 is a perspective view of a valve device according to the embodiment of the present invention.

Fig.-2 is an unrolled plan view of a valve seat for a valve device according to an embodiment of the present invention.

Fig. 3 shows an axial cross-section of a marking pen 10 using the valve device of Figs. 1 and 2, and Fig. 4 is a perspective view of a conventional valve device, known in the prior art, as described above.

Fig. 1 shows a valve device 12 comprising a spring seat 1 and a valve rod 4. Cylinder 2 forms part of spring seat 1 and is provided with a tapered cutaway 3 in its rear portion. The spring seat 1 further comprises a rib 16 which extends from the tapered rear section of cylinder 2, to a cylinder 1' provided at the rear end of said rib 16. The front of said cylinder 11 bears valve spring 10 whilst a hole therethrough supports the rear end of the valve rod 4.

According to the ilustrated embodiment, a cutaway 3 is provided at three equally spaced circumferential k-- positions. However, the quantity may be more or less than three.

Fig. 2 shows a planar unrolled view from the outside of spring seat 1 to show details of the arrangement of the cylinder 2, rib 16 and cylinder The arrangement of other components in this embodiment of the valve device is conventional.

Instead of the cutaway, a groove may be provided in the inner wall of cylinder 2 whose depth becomes gradually smaller towards the front end of the cylinder 2. Such a groove is constructed in the rear section of cylinder 2 and up to an intermediate part thereof. The quantity of the grooves may be single or plural. The shape of the groove may be linear in axial direction or spiral.

Alternatively, the inner diameter in a rear portion of the cylinder 2 may be made to increase gradually towards the rear face. In such a case, it is important to prevent creation of a step gap at a boundary with the rib 16, thereby assuring smooth movement of the valve rod 4.

A marking pen using the valve device shown in Fig. 1 and 2 is shown in fig. 3. A top cylinder 8 is threadedly attached to the front end portion of an axial cylinder. The pen is equipped with a writing member 7. There is an ink leading tube 9 fixedly attached within the front section of axial cylinder 6 for supplying the writing member 7 with ink.

Within axial cylinder 6, a cartridge type ink tank 13 is mounted and is freely movable in an axial direction. Ink tank 13 is equipped with the valve device shown in figs. 1 and 2 at its open end. The rear end of said ink leading tube 9 is attached to and engaged with the front end of the valve rod 4.

z I_ A cap 14 is provided for covering the writing member 7 and, when using the pen, said cap is plugged into the axial cylinder 6 for use as a knock member.

By knocking this cap 14, the cartridge type ink tank 13 is driven forward. The valve rod 4 does not move any further than butting the rear end of the ink leading tube 9. Thus, the-valve device-is opened since the valve rod 4 emerges from the cylinder 2 of the spring seat 1.

When knocking is released, the spring seat 1 is driven back by the force of the valve spring 10. At this time, the piston portion 5 of the valve rod 4 enters the cylinder 2 of the valve seat 1. However, the piston portion 5 first enters the cylinder 2 through cutaway 3. Therefore, ink present in the front section of the cylinder 2 is gradually pressurized according to the width of the cutaway 3.

Where the foregoing groove is provided instead of the cutaway or the inner diameter of the cylinder is made larger, exactly the same effect is obtained as when provided with a cutaway, because the rate of escaping ink pushed by the valve rod and flowing out of the groove or a gap between the inner cylinder wall and the piston portion of the valve rod gradually decreases.

Referring to Fig. 3, there is a fixing tool 19 which is threadedly attached to fix the valve device 12 at the front end of a liquid tank 13.

A o-ring 20 can prevent leakage of ink by being engaged between the fixing tool 19 and the valve seat 11 in close contact with the outer surface of the ink leading tube 9. A seat 21 is located between the liquid leading tube 9 and the writing tool 7 to form a groove 22 for replacing air radially and circumferentially. A ball 18 is housed in the ink tank 13 and is freely movable to agitate any deposit. A tail plug 17 is secured on the inner surface i of the rear end of axial cylinder 6, to detain the liquid tank 13. The composit ' ions of these components, except for improved features of cylinder 2 of the valve device for the marking pen shown' in Fig. 3 are conventionally known in the prior art.

Each component member of a marking pen according to this embodiment of the present invention is made of materials and by means known in the prior 10 art.

1 f

Claims

CLAIMS:

1. A valve device for controlling the supply of liquid from a reservoir to the tip of a writing or coating tool or the like, such device comprising a matingly engaged piston and cylinder arranged for relative movement between open and closed conditions of the valve device in use, wherein a tapered liquid flow path is associated with the piston and cylinder thereof which is arranged to be closed gradually as the piston is engaged with the cylinder so as to avoid abrupt increases in liquid pressure downstream of the valve device when the valve is closed.

2. A valve device as claimed in claim 1 wherein said cylinder is provided with one or more cutaway sections in a circumferential wall thereof, at least in the region of an opening whereby the piston enters said cylinder, wherein said cutaway sections are tapered circumferentially.

3. A valve device a's claimed in claim 1 wherein means whereby said flow path is tapered comprises a radially tapered inner wall of the cylinder.

4. A valve device as claimed in claim 1 wherein means whereby said flow path is tapered comprises one or more tapered grooves.

5. A valve device as claimed in claim 4 wherein said grooves run linearly parallel to the axis of said cylinder.

6. A valve as claimed in claim 4 wherein said grooves are in the form of a spiral.

7. A valve as claimed in claim 1 wherein means whereby said flow path is tapered comprises a radial taper at the end of the piston.

8. A valve device-as claimed in claim 1 wherein means whereby said flow path is tapered comprises one or more tapered grooves on the piston.

i

9. A valve device substantially as hereinbefore described with reference to Figs. 1,2 and 3 of the accompanying drawings.

Published 1988 at The Patent =ce, State House, W71 H4h Holborn, London WC1R 4TP. Purther copies may be obtained from The Patent Ollice, Sales Branch, St Maxy Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187.