Brush and method for applying a liquid to a substrate
The invention relates to a brush comprising a stem and a seat, which may be integral with one or more further brush parts and to which a bundle of hairs is fixed, which bundle can be fed with a liquid, such as ink or paint or the like, from a reservoir.
Such brushes are generally known. E.g., British patent GB 2 255 714 discloses a fountain brush wherein ink can flow from a reservoir, which forms part of the brush stem, to the bundle of hairs via an internal channel so as to feed said bundle of hairs.
European patent application EP 0 197 281 discloses a fountain brush wherein the supply of ink from a reservoir is controlled by an assembly comprising a valve and a spring, which enables the supply of ink from the reservoir to the bundle under axial pressure.
Furthermore, fountain brushes are known wherein the reservoir again forms part of the stem and the wall of said reservoir is flexible, so that ink can be forced from the reservoir to the bundle of hairs by squeezing the reservoir.
The object of the invention is to provide a brush of the above-described type, wherein the supply of liquid from the reservoir to the bundle does not require any separate, frequently recurring operations, such as squeezing or pressing, and wherein the risk of disturbances in the liquid supply is reduced or even practically eliminated.
In order to accomplish that objective, the brush according to the invention is characterised in that the bundle of hairs is surrounded by a sleeve the interior of which communicates with the reservoir and the internal diameter of which is such that the bundle, after having absorbed the liquid, seals the sleeve.
It is preferred that, at least while the bundle is empty, the hairs in the bundle have a certain freedom of movement or at least are not pressed tightly together.
Since the bundle and the liquid absorbed therein, such as ink, paint or the like (hereinafter referred to as "ink"), expands and seals the sleeve, the ink, which is applied to a substrate, such as paper or linen, by means of the brush end, is automatically replenished. Furthermore, the supply of ink will automatically stop when no ink is withdrawn from the bundle. This supply of ink takes place in such a trouble-free manner that the brush according to the invention can also be used in e.g. a computer plotter without having to check the ink supply constantly.
Thus, the bundle and the sleeve effectively form a self-regulating seal. It is preferred that the sleeve is sufficiently long for it to maintain this seal independent of the movements of the bundle during application. In an advantageous embodiment, the sleeve extends almost as far as the end or the tip of the bundle, so as to further improve the supply of ink. In addition, the ratio of the length of the sleeve to the internal diameter of the sleeve is preferably greater than 1.5. This means that if said ratio is e.g. 2, the length of the sleeve is twice as large as the internal diameter.
The invention furthermore relates to a method for applying a liquid to a substrate, for example in order to provide an adhesive edge, to provide a wall with a decorative coating or to make an illustration, wherein use is made of a brush according to the present invention. Such a method can be employed by a person, but also, as briefly referred to above, by a machine, such as a robot arm, a plotter or the like. The brush is preferably held in a more or less vertical position, at least not in a fully horizontal position.
The invention will now be explained in more detail with reference to the figures, which show three embodiments of the brush according to the present invention. Fig. 1 is a cross-sectional view of a first fountain brush according to the present invention.
Fig. 1A is a side elevation and a top plan view of a bundle of hairs suitable for use in the fountain brush
according to Fig . 1.
Fig. 2 is a perspective, sectional view of the fountain brush according to Fig. 1.
Fig. 3 is a cross-sectional view of a second fountain brush according to the present invention.
Fig. 3A is a side elevation and a top plan view of a bundle of hairs suitable for use in the fountain brush according to Fig. 3.
Fig. 4 is a cross-sectional view of a third fountain brush according to the present invention.
Fig. 5 is a perspective, sectional view of the fountain brush according to Fig. 4.
Like parts or parts having like functions are indicated by the same numerals in the various figures. Fig. 1 shows a fountain brush 1 comprising a stem, which is made of a transparent polymer, such as polycarbonate, and two circle-cylindrical portions 2, 3 having different diameters. The upper (in the drawing) portion 2 of the stem has a comparatively large diameter and includes a reservoir 4. The lower portion 3 of the stem has a relatively small internal diameter, for example ranging between 2 and 6 mm, and comprises a channel 5 for the supply of the liquid that is present in reservoir 4 to a bundle of hairs 6. The bundle 6 is fixed in a seat 7, which may be integral with one or more further parts of the fountain brush 1, but which in this specific embodiment comprises a loose element, which is clamped in the lower portion 3 of the stem. The lower part 3 of the stem is sufficiently long for it to form a sleeve 8 for the bundle of hairs 6. The internal diameter of the sleeve 8 and the thickness of the bundle 6 are adapted to each other, such that, at least while the bundle is empty, the hairs in the bundle have a certain freedom of movement or at least are not pressed tightly together. The internal cross-sectional area of the sleeve 8 is preferably significantly larger than the cross- sectional area of the bundle 6 if the latter would be pressed together, in particular when a liquid having a high
viscosity is being used.
As can be seen in the side elevation and the top plan view (Fig. 1A) of the seat 7, said seat 7 comprises four recesses 9 evenly distributed over the circumference of the seat 7, which recesses, together with the inside wall of the lower portion 3 of the stem, form channels 10. Via said channels 10, the cavity defined by sleeve 8 can communicate with the reservoir 4 or at least with channel 5.
The upper side of reservoir 4 is closed by means of a cap 11, which is made of a flexible material, such as rubber or a polyolefin, and which is substantially cylindrical in shape, with an external diameter which is substantially the same as the internal diameter of the reservoir 4. Cap 11 is furthermore provided with a raised edge 12, which ensures an adequate clamping of the cap 11 in reservoir 4. To avoid any chance of spilling or leakage, it is preferred that the reservoir is gas-tight.
When the reservoir 4 is filled, for example with ink, the said ink will flow through channel 5 and channels 9 to the cavity defined by sleeve 8, and fill the bundle 6, which is initially empty. This causes the diameter of the bundle to increase, such that the sleeve 8 is sealed. During the application of the ink to a substrate, such as e.g. paper or linen, the ink is drawn from the bundle and replenished almost simultaneously from the reservoir 4.
The combination of a sleeve and supply of the liquid from outside the bundle, as opposed to supply from within the bundle, yields a further enhanced exchange of liquid (from the reservoir) and tiny air bubbles (between the outer circumference of the brush and the inner wall of the sleeve) and thus further facilitates automatic replenishment of liquid in the bundle.
As long as ink is present in the reservoir 4, the brush can be used without interruption, that is, without regular checks and (manual) adjustment of the amount of ink in the bundle 6 being required. Furthermore, the supply of ink will automatically stop when no ink is withdrawn from the bundle .
The supply of ink, paint or the like in a brush according to the present invention takes place in such a trouble-free manner that said brush can also be used in a plotter, for example, which is controlled by a computer. A plotter makes it possible to obtain illustrations, which are in many respects similar to hand-made oil paintings. For example, the onset of the brush can be visible more clearly and various layers or lines being applied shortly after each other can blend into one another. Thus a much more natural illustration is obtained and an attractive alternative for e.g. desk jet printers and laser printers is offered.
Fig. 3 shows a second embodiment of the brush 1 according to the invention, wherein the lower portion 2 and the upper portion 3 of the stem form part of the same cylindrical body having one internal diameter, for example in a range between 10 and 30 mm. Such a brush 1 is relatively easy to manufacture and can be used for applying wide swaths of the substance present in reservoir 4, such as stain or paint, to a substrate, such as a floor, woodwork or a cloth.
Figures 4 and 5 show a third embodiment of the brush 1 comprising a plunger 13, which is provided with a rubber sealing ring 14 and which can slide inside the reservoir 4. The reservoir 4 can be easily refilled by pushing the plunger 13 downwards, e.g. until it abuts the upper surface of the seat 7, and subsequently placing the tip of the brush 6 and the open end of the sleeve 8 below the surface of e.g. ink or paint in a container (not shown) and drawing the same into the reservoir 4 by moving the plunger 13 upwards . Instead of filling the reservoir 4 with e.g. ink or paint, it is also possible to fill the reservoir 4 with just a so-called medium, such as water or a hydrocarbon. The bundle 6, which will become saturated with the said medium, can then be contacted with a substance consisting of or containing a pigment, and the medium and the pigment can subsequently be applied to a substrate, such as a sheet of paper. It was found that the total amount of medium required to apply a pigment to a substrate thus can be reduced
considerably. Furthermore, the bundle 6 can be cleaned in a simple and efficacious manner by forcing a small amount of medium from the reservoir 4 through the bundle 6.
The invention is not restricted to the embodiments as described above, which can be varied in several ways without departing from the scope of the claims . For instance, the brush according to the present invention is also suitable for handling high viscosity liquids, such as oil paint, soap, glue and oil. Furthermore, it is not necessary for the sleeve to be integral with e.g. the brush stem, but it can also be a detachable part.