DESCRIPTION OF INVENTION
Title: "A holder for an applicator and a dispenser for liquids or pastes having such a holder"
THIS INVENTION relates to a holder for an applicator and a dispenser for liquids or pastes having such a holder.
It is well known that a number of products based in solvent of a very low flushing point, or high volatility, for fast drying are available from the trade in containers which are usually tightly closed with a cap which holds a dipping brush, since most of these products are to be dispensed from brush onto a substrate for example plastic pipe by plumbers. However, during use the solvent evaporates from the container, thus changing the coefficient of viscosity.
Whereas the viscosity of the product or material has always been carefully calculated it Jigs been to date always extremely difficult to retain that viscosity since the containers are open to the air during use; furthermore, opening the container by unscrewing its cap has always been very difficult, particularly after it has been used once because a deposit is left on the thread which locks the cap to the container, making it extremely difficult or impossible to remove the cap, particularly in the case of plumber's work.
It is an object of this invention to overcome these problems of dispensing liquids or pastes, such as typewriting correction fluid, for example Tipp-Ex (Registered Trade Mark) for use in offices, plumbers' glue and liquid plastics, touch up car paint, soldering flux and many other products similarly packed.
According to one aspect of the present invention there is provided a dispenser for liquids or paste, the dispenser having a first chamber for containing liquid or paste, a second chamber, means for supporting an applicator so that the applicator is in communication with the first and second chambers and means for expanding the second chamber to cause liquid or paste to be sucked up from the first chamber onto the applicator.
According to α second aspect of the present invention there is provided a holder for an applicator for applying liquid or paste to a substrate, the holder comprising means for supplying liquid or paste to an applicator in the holder and sealing means for providing a seal between the holder and a cap for closing an opening of a container for liquid or paste so that, when the holder is received in the container opening, relative movement of the holder and the cap causes liquid or paste to be supplied by suction to an applicator in the holder as the cap is removed from the container and causes liquid or paste to be returned to the container as the cap is replaced to close the container opening.
Thus, a dispenser embodying the invention enables the viscosity of the liquid or paste to be sustained, by being easy to open and close. Moreover, the dispensing of the liquid or paste product may be largely improved because a top quality brush, which eliminates the repeated supply of a poor quality brush with each container, may be used as the applicator since the brush and the applicator supporting means or holder can be reused with a new first chamber or container.
For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings in which:
FIGURE I is a vertical cross-section through part of a first embodiment of a dispenser for liquid or paste in accordance with the invention;
FIGURE 2 is a vertical cross-section through part of a second embodi¬ ment of a dispenser for liquid or paste in accordance with the invention; and
FIGURE 3 is a vertical cross-section through part of a third embodiment of a dispenser for liquid or paste in accordance with the invention.
Referring now to Figure I there is shown a vertical cross-section through part of a first embodiment of a dispenser I for dispensing liquids, for example Tipp-Ex (Registered Trade Mark) liquid), plumbers' glue and liquid plastics, car touch-up paint, soldering flux or the like.
As shown in the drawing, the dispenser I comprises a first chamber or
container 2 providing a reservoir for the liquid or paste to be dispensed, supporting means in the form of a holder 3 for carrying an applicator brush 4, so that the bristles of the brush extend away from the holder 3, and a cap 5 for closing the container 2. It should, of course, be appreciated that the dispenser I has rotational symmetry about the vertical axis 6 and that, moreover, the container 2 can have any suitable shape. The container is preferably moulded of a plastics material such as polyethylene or is formed of a metal or metal alloy such as tin.
The brush holder 3 comprises an essentially cylindrical body which is preferably moulded of plastics material. One end 3a of the brush holder 3 comprises a radially outer brush ring 7 and a radially inner brush ring 8 which define therebetween an annular recess or cavity for receiving the brush 4. A bore 9 extends through the brush holder 3 along the axis thereof to supply liquids stored in the body to a brush 4 received in the brush holder 3. The other end 3b of the brush holder 3 is formed with a plurality of slits 10, extending parallel to the axis of the brush holder and a rim I I , extending radially outwardly of the holder 3 so that when the brush holder 3 is inserted into a neck 12 of the container 2 the rim I I forms a snap fit with a shoulder 13 of the neck 12, the slits 10 providing the necessary flexibility for the end 3b of the brush holder 3.
A stopping or abutment rim 14 is provided on the brush holder 3 intermediate the ends 3a and 3b thereof to limit the amount to which the brush holder can be inserted into the neck 12.
The brush 4 is made of fibres, such as nylon, that are not affected by acid or solvents. The brush 4 is provided with a centre hole or channel 17 which when the brush is received in the brush holder 3 between the inner and outer brush rings 8 and 7 thereof forms a prolongation of the bore 9 so that the liquid or paste can pass through the bore 9 and the channel 17 to the brush 4. The length and diameter of the bore 9 and the channel 17 are calculated in accordance with the properties, In particular the viscosity, of the liquid or paste to be passed through the bore 9 and channel 17 to be dispensed with the brush 4 onto a substrate (not shown). The brush 4 is inserted into the cavity provided for it in the brush holder 3 which forms the first part of the closure of the dispenser I. The brush holder 3 is pushed inside the neck 12 to provide a
tight fit therewith so that the lower rim 1 1 of the holder 3 which has the slits
10 for its flexibility enters the neck 12 and snaps back under the inside shoulder
13 of the neck 12 to secure the brush holder in position. The stopping rim 14- is provided to seal the container 2 and stop the brush holder 3 from getting too far inside the container 2. The brush holder 3 has further been provided, intermediate the end 3a thereof and the stopping rim 14 with a groove or several grooves 15 to receive the or a respective 0-ring 16, the size or number of the 0-rϊngs and grooves being determined in accordance with the contents of the container 2. The 0-ring sealing means and the cap define a second chamber Grid the brush communicates with both the first and second chambers. The brush 4 is sunk deep inside the holder 3 so as to allow room for any overflow of the container contents. The top edge of the brush holder 3 has a very smooth and accurate edge which provides a tight seal 3' between the cap 5 and the brush holder when the cap is put on.
The cap 5 may be of any desired external shape but is preferably made so that the outside diameter is large enough to provide a good gripping surface to enable the cap to be removed from the container. Cap 5 defines a small second chamber to accommodate the brush 4 and is totally sealed by the brush holder's top edge once the two are in a closed or engaged condition. A substantially cylindrical inner surface are 19 of the cap 5 is provided with a high or smooth finish to enable the 0-rings to move up or down along that cylindrical surface area.
In use of the dispenser shown in Figure I , when the cap 5 is removed to enable use of the liquid or paste stored in the container 2, the seal provided between the cap 5 and the brush holder 3 by the O-rϊng(s) 16 causes the pressure inside the second chamber 18 to drop when the tight seal between the cap 5 and the upper edge of the holder 3 is broken. The liquid or paste inside the container 2 is drawn upwardly by the suction force produced by this pressure reduction through the bore 9 and the channel 17 to the brush 4 ready for application to a substrate. After use of the contents of the container, the cap 5 is replaced and because of the 0-ring seal(s) the pressure inside the second chamber or cavity 18 increases forcing the liquid or paste which has overflowed round the brush back into the container via channel 17 and the bore 9.
Figure 2 shows an alternative embodiment of a dispenser in accordance with the present invention. Again, it should be appreciated that the dispenser has rotational symmetry about the axis 6.
As shown in Figure 2, the dispenser comprises a container or bottle 19 having an elongate neck 20. The neck 20 is formed with a screw-thread 21 for engaging a complementary screw-thread 22 of a cap 23 for the bottle. Above the screw-thread 21 , a plurality of 0-rings 24 are carried by respective grooves 25 formed in the neck 20 of the bottle 19. The 0-rings 25 serve to provide a seal between the cap 23 and the neck 20 of the bottle when the cap is screwed onto the bottle.
An applicator supporting means or holder 26 snap-fit engages within the neck of the bottle. The holder 26 is provided with a circumferential protrusion 27 which engages in an annular recess 28 formed in the interior surface of the neck 20 of the bottle to ensure that the holder 26 snap-fits into the correct position within the neck of the bottle. The brush holder 26 is provided with an annular flange 29 which, when the brush holder is snap-fitted within the neck 20 of the bottle, extends over a free edge of the neck 20 of the bottle 19. A circumferential surface 29£ of the flange 29 is formed with a diamond pattern or otherwise roughened to assist in the removal of the brush holder from the container or bottle 19. As in the previous embodiment shown in Figure 1 , the brush holder 26 is provided with slits or slots 30 for flexibility and so as to reduce the amount of material required to manufacture the brush holder 26. An applicator in the form of a brush 31 is mounted in a cavity formed in the brush holder 26 as in the arrangement shown in Figure I by means of a brush mounting ring 32. The brush - 31 communicates with the first chamber formed by the bottle or container 1 by a channel 33 extending centrally through the brush and the brush holder 26.
An interior surface of the cap 23 is formed with an annular V-shaped cross section projection 34 which is arranged to engage a top surface of the flange 29 of the brush holder when the cap is fully screwed onto the neck of the bottle so as to provide a fluid tight seal to prevent any liquid or paste escaping from the dispenser.
The bottle or container 19 is preferably formed by injection and stretch-
blow moulding, the neck of the bottle being formed by injection moulding so as to ensure accuracy in the formation thereof. The cap 23 and the brush holder 26 are also preferably formed by injection moulding from thermoplastics material.
In use of the dispenser shown in Figure 2, when the cap 23 is unscrewed from the neck of the bottle, the seal between the projection 34 and the flange 29 of the brush holder is broken and, as the cap is unscrewed, the second chamber expands, the seal between the cap 23 and the neck 20 of the bottle 19 causing the pressure within the second chamber to drop so that the liquid or paste inside the container 19 is drawn upwardly by the suction force produced by the pressure reduction through the channel 33 to the brush 31 ready for application to a substrate. After use of the contents of the container, the cap 23 is replaced and, because of the 0-ring seal(s), as the cap is screwed onto the neck of the bottle, the second chamber contracts so increasing the pressure within the second chamber and forcing any liquid or paste which has overflowed round the brush back into the bottle 19.
Figure 3 is a vertical cross-sectional view of part of a modified version of the dispenser shown in Figure 2, the cap 23 being omitted in Figure 3.
As shown in Figure 3, the applicator supporting means or holder 26' is modified so as to omit the protrusion 27. Rather, in the arrangement shown in Figure 3, as in the Figure I arrangement, a lip 35 is provided which snap fits beneath a shoulder 36 of the neck 20 of the container. The holder 26' has a reduced diameter cylindrical hollow extension 37 which defines the channel or passage 33' through which liquid a paste can communicate with the brush. Also, in the arrangement shown in Figure 3, the projection 34 is provided on the flange 29 rather than on the cap of the dispenser. In another respects, the arrangement shown in Figure 3 is similar in operation and construction to that shown in Figure 2. Of course, in either arrangement, the number of grooves 25 and corresponding 0-ring seals 24 can be modified to suit requirements.
It should, of course, be appreciated that the brush may be replaced by any other form of applicator, for example, a felt or foam applicator or a rotatable cylinder applicator. Also, any other suitable form of sealing means may be provided between the cap 5 and the holder 3 in Figure I or the cap 23
and the bottle neck 20 in Figure 2 or Figure 3. Thus, for example, in the Figure I arrangement a sealing rim could be moulded onto the holder 3a or, in fife Figure 2 or Figure 3 arrangement, onto the neck 20 of the container 1 .