GB2037946A - Liquid transfer or applicator device - Google Patents

Abstract

A liquid transfer or applicator device for use in a conveyor belt or as a flat applicator or a roller applicator 1 for the application of paint or the laying-up of resins has a surface formed with a number of intersecting walls 3 of resiliently flexible impermeable material, such as natural or synthetic rubber, subdividing the surface into a number of identical open cells, each sufficiently small to retain a quantity of the liquid by surface tension. The walls of the cell buckle as the device is pressed against a surface, for example with a rolling action, to expel the contents of the cell onto the surface. Each cell may be filled with porous material. <IMAGE>

Description

SPECIFICATION Liquid transfer or applicator device This invention relates to a liquid transfer or applicator device for the picking-up, transporting and depositing of a liquid.

The invention is particuiarly, but not exclusively, applicable to devices for the application of liquids such as paint or adhesive to a surface to be coated.

It is common to employ a roller having an absorbent cellular surface for the applicatiqn of liquids such as paint to surfaces. Such rollers are not in general satisfactory for the saturationcoating of absorbent surfaces with paint or adhesive, for example, in the application of liquid resin to a glass fibre "mart" or laminate. The coating of such porous or highly absorbent surfaces can be time-consuming, since many strokes of a brush or roller applicator are generally necessary to force the resin or other liquid into the pores of the surface to saturate the surface.

Furthermore, when applying adhesive glue or paint to a highly porous or absorbent surface using a conventional brush or roller it is not possible to control with any precision the amount of liquid applied.

An object of the present invention is to provide a device of simple construction which is capable of applying liquids to highly absorbent surfaces, and in controlled quantities.

The present invention accordingly provides a liquid transfer or applicator device for the pickingup, transporting and depositing of a liquid, the device having a base surface formed with a number of intersecting upstanding walls of resiliently flexible impermeable material which define a plurality of open cells, the walls of each cell being such that the cell collapses when it is pressed against a surface by an applied pressure to expel the contents of the cell onto the surface, the cell expanding when the pressure is released to draw liquid and/or gas from the surface.

The cells of the device can be charged with liquid by pressing the cellular surface of the device against a wall of a liquid reservoir. The flexible walls of the cells buckle, collapsing the cells and allowing the liquid to enter the cells when they resume their normal shape due to the resilience of the cell walls. The uniform size of the cells ensures that when charged with liquid in this way the cells carry a predetermined amount of liquid. The liquid would normally be retained in the cells by surface tension. For some applications, for example in the application of paint, it may be advantageous to incorporate a resilientiy flexible porous filling in each cell for the absorption of a liquid charge.

The expansion of each cell after it has been collapsed against a surface draws gas bubbles and/or surplus liquid from the surface, and assists in consolidating the surface when, for example, impregnating a glass fibre mat with liquid resin.

The upstanding walls of the device preferably intersect each other at right angles to form identical cells having square or rectangular open sides parallel to and spaced from the surface of the device.

The said surface of the device may be covered by a layer of the same material as that forming the upstanding walls, said layer forming the bottom surface of each cell. Preferably the said layer and the upstanding walls forming the cells are moulded integrally with each other in resilient plastics, natural rubber, synthetic rubber, or other elastomeric material.

The device of the invention may be embodied as a flat applicator, or as a roller applicator. In the latter case the said surface would be a cylindrical surface of a roller which is freely rotatably mounted in a support for rotation about its axis.

The roller support is preferably attached to a rigid elongate handle extending perpendicularly to the axis of the roller.

The device of the invention has practical application both as an applicator for the application of liquids to surfaces, and as a liquid conveyor. In the latter case the device may be embodied in a surface of a conveyor belt for the transfer of liquid.

The invention will now be further described, by way of example, with reference to the accompanying purely diagrammatic drawings, in which: Figure 1 is a perspective view of a roller for use in a roller applicator device embodying the invention; Figure 2 is a transverse cross-sectional view, on an enlarged scale, of part of the roller illustrated in Figure 1, illustrating its operation, and Figure 3 is a perspective view of a roller applicator incorporating the roller illustrated in Figures 1 and 2.

Figures 1 and 2 of the drawings show a roller 1 for use in a liquid applicator device for the picking up, transporting and depositing of a liauid, such as, for example, a liquid resin or paint. The roller 1 is freely rotatably mounted upon a shaft 2 for rotation about its axis X-X. The roller 1 has a cylindrical base surface which is provided with a number of intersecting upstanding walls 3 of resiliently flexible impermeable material, in this case, synthetic rubber.The walls 3 are formed in two sets which intersect each other at right angles, one set of walls 3 extending along generatrices of the cylindrical surface and lying in pianes containing the axis X-X of the roller, while the other set of wails 3 are disposed in parallel planes perpendicular to the axis X-X, the two sets of intersecting wails beinsq spaced apart at equal intervals so as to define identical open cells of square shape with square open sides parallel to and spaced from the bottom walls of the cells, which lie on the cylindrical surface of the roller 1.

As shown in Figure 2, the cell walls 3 are moulded integrally with a base layer 4 which forms the bottom surface of each cell and which covers the cylindrical surface of the roller.

The essential characteristic of the applicator device is that the cell walls 3 are resiliently flexible, so that when the roller is pressed against a surface the walls 3 in contact with the surface buckle, collapsing the cells defined by these walls.

In order to charge the cells of the roller with liquid to be applied to a surface the roller is rolled along the bottom of a reservoir containing the liquid, while applying pressure to the roller to buckle the cell walls which contact the bottom of the reservoir. As the roller is rotated about its axis the cell walls which have been buckled by contact with the bottom of the reservoir resume their normal shape by virtue of the resilience of the cell walls, and in so doing draw in a quantity of liquid from the reservoir. When all the cells of the roller have been filled with liquid in this way by rotation of the roller in the reservoir the roller is lifted out of the reservoir. After draining of surplus liquid a charge of liquid will remain in each cell, retained by the surface tension of the liquid.Moreover, since the cells are of uniform size they will all contain a substantially identical charge of liquid.

The charged roller can then be used for applying the liquid to an absorbent surface, for example, a layer of glass fibre, by rolling the roller along the surface while applying pressure to the surface through the roller, as illustrated in Figure 2. This rolling process is the reverse of the process by which the roller picks up liquid: as each cell collapses due to the buckling of its walls 3 upon contact with the absorbent surface the liquid contents of the cell are discharged onto the surface.Furthermore, the edges of the buckled walls form an effective seal with the surface, so that the application of pressure to collapse the cell effectively forces the liquid contents of the cell under pressure into the absorbent surface, giving rise to good penetration of the surface by the liquid, as illustrated diagrammatically in Figure 2, where a surface layer 5 is shown saturated with liquid. The liquid charge in each cell is shown diagrammatically by reference numeral 6 in Figure 2, the direction of rotation of the roller 1 being indicated by the arrow R.

The amount of liquid discharged from each cell into the absorbent surface is predeterminable, since it will be related to the size of each cell, assuming that the cells are charged properly with liquid as described above. If it is desired to apply a smaller quantity of liquid to the surface the roller may be passed over the surface to be coated with the application of a smaller pressure, so that the cells do not collapse completely in contact with the surface.

As the roller 1 advances each cell reverts to its original shape after being collapsed against the surface. In so doing the cell draws air bubbles from the surface, assisting in the consolidation of the resin-impregnated layer 5.

The choice of the material used to form the walls 3 of the cells will, of course, depend upon the chemical nature of the liquid to be handled by the device. The resilience of the cell walls 3 will determine the pressure which has to be applied to the roller, in the direction indicated by arrow P in Figure 2, to collapse the cells and discharge the liquid contents thereof. For use in the impregnation of glass fibre with liquid resin it is desirable that the cell walls 3 should be of somewhat higher stiffness, requiring a higher pressure P to be applied to the roller to collapse the cells than is necessary for a roller used for simple coating purposes, so that the glass fibres are collapsed by the action of the roller, minimizing the amount of resin required to impregnate the fibres.

Figure 3 shows an applicator embodying the roller 1 of Figures 1 and 2. The shaft 2 of the roller 1 is formed by a straight end portion of a single metal rod 7. At one end of the shaft 2 the rod 7 is formed with a U-shaped portion 8 having parallel arms 9, 10 which are parallel to and coplanar with the shaft 2 and, therefore, with the axis of the roller 1. The arm 9 nearer the shaft 2 is located in a transverse notch 11 in one end of a flat elongate wooden handle 12 which is generally coplanar with the axis of the roller 1. The other arm 10. of the U-shaped portion is engaged in a transverse bore 1 3 in the handle, parallel to the notch 11, while the portion of the rod 7 which interconnects the arms 9 and 10 is seated in a groove 14 extending along one edge of the handle 12.

The flat handle 12 is easy to use, and can easily have an extension handle attached to it, for example by nailing onto its flat face, to enable the roller applicator device to be used on relatively inaccessible surfaces.

Claims (11)

1. A liquid transfer or applicator device for the picking-up, transporting and depositing of a liquid, the device having a base surface formed with a number of intersecting upstanding walls of resiliently flexible impermeable material which define a plurality of open cells, the walls of each cell being such that the cell collapses when it is pressed against a surface by an applied pressure to expel the contents of the cell onto the surface, the cell expanding when the pressure is released to draw liquid and/or gas from the surface.

2. A device as claimed in Claim 1, in which the upstanding walls intersect each other at right angles to form identical cells having square or rectangular open sides parallel to and spaced from the base surface of the device.

3. A device as claimed in Claim 1 or Claim 2, in which the walls consist of natural or synthetic rubber.

4. A device as claimed in any one of the preceding claims, in which the said base surface of the device is covered by a layer of the same material as that forming the upstanding walls, said layer forming the bottom of each ceil.

5. A device as claimed in Claim 4, in which the said layer and the upstanding walls forming the cells are moulded integrally with each other.

6. A device as claimed in any one of the preceding claims in which the base surface is a cylindrical surface of an applicator roller which is freely rotatably mounted on a support for rotation about its axis.

7. A device as claimed in any one of the preceding claims in which each cell is filled with a resiliently flexible porous material for the absorption of a charge of liquid.

8. A device as claimed in claim 6, in which the roller support is attached to a rigid elongate handle extending perpendicularly to the axis of the roller.

9. A device as claimed in claim 8, in which the roller support comprises a metal rod having a first straight end portion on which the roller is rotatably mounted, and a generally U-shaped portion at the other end of the rod, the arms of the U-shaped portion being generally parallel to the first end portion and being engaged in respective transverse notches or bores in the handle.

10. A device as claimed in claim 8 or claim 9, in which the handle is a flat member of wood, plastics or metal which is substantially coplanar with the axis of the roller.

11. A liquid transfer or applicator device substantially as herein described with reference to and as shown in the accompanying drawings.