GB2242121A

GB2242121A - Liquid applicator

Info

Publication number: GB2242121A
Application number: GB9104310A
Authority: GB
Inventors: Nobuyuki Nakazima
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1990-03-02
Filing date: 1991-03-01
Publication date: 1991-09-25
Also published as: ITMI910546A0; IT1252313B; DE4106578A1; JPH03115077U; ITMI910546A1; FR2659032A1; JP2525539Y2; GB9104310D0; CA2037259A1

Abstract

In order to enable the reservoir (17) to contract as it supplies liquid to an applicator member (2), it is made of a deformable material such as plastics or metal foil. In order to prevent air bubbles from being sucked into the reservoir (17), one or more check valves (18) are provided. <IMAGE>

Description

LIQUID APPLICATOR The present invention relates to a liquid applicator for

dispensing a liquid such as a liquid cosmetic, a hair dye liquor, a writing ink or a paint by pushing the rear end of a shaft so as to Introduce liquid into an applicator member at the front end of the shaft. The liquid may then be applied to a surface by the applicator member.

A conventional liquid applicator of the above type, as shown in Figs. 7 through 9, is described below.

An outer shaft 1 is screwed at its front end into a front shaft 3 which has a brush 2 fixed to its front end. A pipe 4 is inserted through the brush 4 and a liquid delivery tube 5 fixed to the outer shaft 1 extends into the pipe 4. An inner shaft 6 contains an applicator liquid and is slidably inserted in the outer shaft 1. Between the inner shaft 6 and the liquid delivery tube 5 is interposed a packing 7 which prevents the applicator liquid from leaking between the two components.

Adjacent the rear end of the liquid delivery tube 5 is provided in the inner shaft 6 a valve stem 8 which can slide in a guiding portion 6b of the inner shaft 6.

The valve stem 8 comprises a valve portion 8a abuttable against a valve seat 6a of the inner shaft to constitute a valve, a piston portion 8b and a skirt portion 8c attached to the piston portion 8b.

A spring 9 is used to close the valve by pressing the valve portion Ba of the valve stem 8 against the valve seat 6a. By pushing a push portion 6c at the rear end of the inner shaft 6 towards the front shaft 3, the pressure of the liquid in the inner shaft 6 is increased because it is compressed by the piston portion 8b, and the liquid flows around the skirt portion 8c and into the liquid delivery tube 5 once the valve seat 6a has separated from the valve portion Sa.

The liquid enters the liquid delivery tube 5 through an opening 5a and then flows into the brush 2 after passing through the pipe 4, so that the liquid may be applied to a surface by the brush 2.

When the pushing of the push portion 6c of the inner shaft 6 is stopped, the inner shaft 6 slides withir- tei.,- outer shaft 1 in the direction away from the front shaft 3 under the influence of the spring 9.

Because the valve portion Ba of the valve stem 8 returns to being seated an the valve seat 6a as a result of the restoring force of the spring 9, the liquid already discharged is prevented from returning into the inner shaft 6 and the pressure in the inner shaft 6 becomes negative.

For the reason, if the inner shaft 6 is pushed and released several times, the negative pressure increases, and there is the possibility that the amount of the liquid discharged into the brush 2 by a single push action decreases until it is zero.

Furthermore, when the above-described valve is opened and then closed, some airflows back into the inner shaft 6 to form air bubbles in the liquid. These air bubbles decrease the amount of the liquid that can be discharged into the brush 2.

In order to prevent such a decrease in the amount of liquid discharged, there has been proposed a liquid applicator as shown in Fig. 10.

This liquid applicator has slidable piston 10 inserted in the rear end of the inner shaft 6 of a liquid applicator of the type shown in Figs. 7 through 9. When the pressure of the liquid in the inner shaft 6 becomes negative, the piston 10 slides within the inner shaft 6 so as to keep the pressure of the liquid at atmospheric pressure, whereby the amount of liquid discharged by a single push action of the push portion 6c of the inner shaft 6 remains constant.

However, when the liquid applicator as shown in Fig. 10 is allowed to stand for many hours, the liquid often penetrates into the space between the inner shaft 6 and the piston 10, where it becomes dry or solidifies and prevents the piston 10 from sliding. Then, when the push portion 6c is pushed, the pressure of the liquid in the inner shaft 6 becomes negative in the same way as in the liquid applicator shown in Fig. 7. Thus, the applicator of Fig. 10 suffers from the same problems as the liquid applicator of Fig. 7.

According to the present invention, there is provided a liquid applicator comprising: an outer shaft; an applicator member mounted on the front end of the outer shaft; an inner shaft slidably mounted in the outer shaft; a liquid delivery tube mounted in the outer shaft and extending into the inner shaft for guiding liquid from C-.e inner shaft towards the applicator member; a valve mounted in the inner shaft for controlling the flow of liquid into the liquid delivery tube; a reservoir for containing a liquid, the reservoir being deformable and mounted in the inner shaft, the inner shaft being vented to the atmosphere surrounding the liquid applicator; and check valve means provided between the applicator member and the liquid reservoir for controlling the flow of the liquid therebetween.

The invention will now be described by way of non-limiting embodiments with reference to the accompanying drawings, in which:- Fig. 1 is a cross-sectional view of one embodiment of the present invention; Fig. 2 is a cross-sectional view of a check valve of the liquid applicator of Fig. 1; Fig. 3 is a perspective view of another form of the check valve of Fig. 2; Figs. 4 through 6 are cross-sectional views of other embodiments of the present invention; Fig. 7 is a cross-sectional view of a conventional liquid applicator; Fig. 8 is a cross-sectional view of the applicator of Fig. 7, showing a valve; and Fig. 9 is a perspective view of the valve stem of the valve of Fig. 8; Fig. 10 is a crosssectional view of another conventional liquid applicator.

With reference to the embodiment of Figs. 1 and 2, a front shaft 3 is screwed onto an outer shaft 1 so that a body portion 11 provided with a liquid delivery tube 5 and a packing piece 12 are sandwiched together between the front shaft 3 and the outer shaft 1. A pipe 4 opening into a brush 2 is inserted into the liquid delivery tube 5.

Onto the front end of an inner shaft 6 an inner front shaft 13 is screwed so that a valve seat body 14 and a guiding tube 15 are fixed between the inner shaft 6 and the inner front shaft 13. A packing7 supported between the inner front shaft 13 and the valve seat body 14 is fitted around the liquid delivery tube 5 to prevent the liquid from leaking past the liquid delivery tube 5.

Adjacent to the liquid delivery tube 5, a valve stem 8 is held within the guiding tube 15, and the valve stem is provided with a valve portion 8a which is abuttable against a valve seat 6a of the valve seat body 14 to constitute a valve, a piston portion 8b supporting a spring 9 between it and the guiding tube 15, and a skirt portion 8c which projects from the piston portion 8b and rubs against the inside surface of the guiding tube 15. The guiding tube 15 is made so as to guide the sliding of the valve stem 8.

The inner shaft 6 is provided with a partition wall 6d in which a screw hole is bored, and into this screw hole is screwed a soft and readily deformable liquid reservoir 17 which is of tubular form and contains liquid and is made of polyethylene, thin metal foil or the like.

Between the liquid reservoir 17 and the screw hole of the partition wall 6d is fixed a check valve 18 as shown in Fig. 2.

In relation to the check valve 18, when the pressure on the guiding tube 15 side of the partition wall O'd of the inner shaft 6 becomes negative, hinged f lap 18a is opened on the guiding tube 15 side so as to permit the liquid to flow from the opening 17a an the liquid reservoir 17 side into the inner shaft 6.

When the pressure an the guiding tube 15 side of the inner shaft 6 becomes positive, the hinged flap 18a is closed by the pressure, so that it presses tightly against the opening 17a and the movement of liquid through the opening 17a is prevented.

At the rear end of the inner shaft 6 is fitted a push portion 19 having an air hole 19a.

When the push portion 19 is pushed towards the front shaft 3, the inner shaft 6 slides within the outer shaft 1 towards the front shaft 3.

The valve stem 8 moves towards the front shaft 3 together with the inner shaft 6 until it hits against the liquid delivery tube 5 and it then slides within the guiding tube 15 in opposition to the spring 9.

As a result of the projection of the liquid delivery tube 5 into the inner shaft 6 due to the sliding of the inner shaft 6 into the outer shaft 1, as well as the movement of the piston portion Bb within the guiding tube 15 once the valve stem 8 is being pushed by the liquid delivery tube 5, the pressure of r k the liquid in the inner shaft increases. As a result the hinged flap 18a of the check valve 18 closes the opening 17a to the liquid reservoir 17 to prevent the liquid from flowing backwards into the liquid reservoir 17.

Then, because the valve stem 8 is pushed by the guiding tube 15, the valve portion 8a separates from the valve seat 6a and the valve opens, so that the liquid flows into the inner front shaft 13 by pushing past the skirt portion 8c, flows into the liquid delivery tube 5 through the opening 5a and flows through the pipe 4 to the brush 2.

By applying the liquid held in the brush 2 to a surface (for example, a sheet of paper), letters or figures may be drawn.

When the user no longer pushes the push portion 19, the guiding tube 15 is pushed by the restoring force of the spring 9, so that the inner shaft 6 slides in the direction away from the front shaft 3. During this sliding, the pressure on the guiding tube 15 side of the partition wall 6d of the inner shaft 6 becomes negative, and the hinged flap 18a of the check valve 18 therefore opens the opening 17a to the liquid reservoir 17 to permit the liquid in the reservoir 17 to flow to the guiding tube 15 side, thereby restoring the pressure to atmospheric pressure.

Furthermore, since the compartment of the inner shaft 6 that houses the liquid reservoir 17 communicates with the outside atmosphere through the air hole 19a, the liquid which flows out of the reservoir 17 deforms the liquid reservoir 17, i.e. causes it to contract to the same extent that liquid flows to the guiding tube 15 side in order to prevent the pressure in the reservoir from becoming negative.

The restoring force of the spring 9 causes the valve stem 8 to close the space between the valve seat 6a and the valve portion 8a to prevent air from being sucked in from the brush 2, so that the formation of air bubbles in the liquid in the inner shaft 6 as a result of incoming air is prevented.

Instead of being as shown in Fig. 2t the cheek valve 18 may have a bowllike piece 18b having a plurality of radial cuts 18c as shown in Fig. 3.

With such a check valve, when the pressure on the convex side of the bowllike piece 18b becomes negative, the cuts 18c open towards that side so that liquid may flow out of the reservoir 17.

When the pressure an the concave side becomes negative, the cuts 18b seal against each other and prevent liquid from flowing into the reservoir 17.

Fig. 4 shows another example of the present invention.

In the embodiment of Fig. 1, the check valve 18 is provided between the inner shaft 6 and the liquid reservoir 17 on the partition wall 6d of the inner shaft 6, while in the embodiment of Fig. 4 it is provided between the liquid delivery tube 5 and a pipe 16 sticking into the brush 2.

This check valve 18 is closed by negative pressure of the liquid in the inner shaft 6 produced when the pushing of the push portion 19 is stopped, and the formation of air bubbles in the liquid is prevented.

Then, the liquid reseroir 17 is compressed by atmospheric pressure by as much as the amount of liquid previously discharged into the brush 2, so that the pressure of the liquid does not become negative. Thus, the amount of the liquid discharged during the next push action is the same as before.

Fig. 5 shows still another embodiment of the present invention, in which use is made of the check valve 18 of Fig. 1 and the check valve 18 of Fig. 4. Since the action of each check valve 18 is the same as described previously, no further explanation will be given.

Fig. 6 shows a further embodiment, in which in place of the brush 2 of Fig. 1 use is made of a comb having hollow teeth 20 provided with discharge ports 20a in their front ends. In this liquid applicator the liquid is discharged from the discharge ports 20a of the teeth 20 by a push action on the push portion 19, so that, if the user's hair is combed while discharging the liquid, it can be utilized for hair dyeing, etc. The Fig. 6 embodiment operates in the same manner as the Fig. 1 embodiment.

In the above embodiments of the present invention, the soft liquid reservoir is compressed and deformed by atmospheric pressure to the extent that liquid has been discharged from the inner shaft. Thus, the pressure of the liquid in the inner shaft never becomes negative and therefore the amount of liquid discharged does not decrease because of a build up of the negative pressure.

V Furthermore, because of the check valve(s) the liquid in the inner shat is prevented from generating negative pressure, and, by hampering the backwards flow of air from the applicator member, the formation of air bubbles in the liquid due to incoming air from the applicator member Is prevented, and any decrease in the amount of liquid discharged due to the presence of air bubbles is also prevented.

Still furthermore, since no use is made of the'prior art piston the problems resulting from liquid drying or solidifying and jamming the piston do not arise.

Claims

1. A liquid applicator comprising:

an outer shaft; an applicator member mounted on the front end of the outer shaft; an inner shaft slidably mounted in the outer shaft; a liquid delivery tube mounted in the outer shaft and extending into the inner shaft for guiding liquid from the inner shaft towards the applicator member; a valve mounted in the inner shaft for controlling the flow of liquid into the liquid delivery tube; a reservoir for containing a liquid, the reservoir being defdrmable and mounted in the inner shaft, the inner shaft being vented to the atmosphere surrounding the liquid applicator; and check valve means provided between the applicator member and the liquid reservoir for controlling the flow of the liquid therebetween.

2. A liquid applicator according to claim 1, wherein the check valve means comprises a check valve located between the valve and the reservoir.

3. A liquid applicator according to claim 1, wherein the check valve means comprises a check valve located between the liquid delivery tube and the applicator member.

4. A liquid applicator according to claim 1, wherein the check valve means comprises a first check valve located between the valve and the reservoir and a second check valve located between the liquid delivery tube and the applicator member.

5. A liquid applicator according to any one of claims 1 to 4, wherein the or each check valve is (a) of the type having a single f lap across an opening and openable in response to liquid flow from the reservoir to the applicator C -g- member and claseable in response to liquid flow from the applicator member to the reservoir or (b) of the type having an opening and a plurality of radially inwardly extending flaps cooperable to abut against one another to form a dame closing the opening in response to liquid flow from the applicator member to the reservoir and arranged to separate from one another to open the opening in response to liquid flow from the reservoir to the applicator member.

6. A liquid applicator according to any one of claims 1 to 5, wherein the reservoir has longitudinal walls which are deformable towards one another to expel the liquid from the reservoir.

7. A liquid applicator according to any one of claims 1 to 6, wherein substantially the full length of the inner shaft is located inside the outer shaf t.

8. A liquid applicator substantially as herein described with reference to and as illustrated in Figs. 1 to 6 of the accompanying drawings.

9. All novel features and combinations thereof.

Published 199) at The Patent Concept House. Cardiff Road. Neuport. Gwerit NP9 I RH. Further copies m&%, be obwned from Sales branch. Unn 6. Nine Mile Point. CAT;,;'el;nfarb. Cross Keys. NeuWrt. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.