Traditionally there are two main methods of buttering bread by automated equipment.

One known method is contact buttering in which an applicator such as a roller, loaded with softened butter, contacts the bread slice passing under the applicator so as to apply butter to the bread surface. The thickness of the layer of butter on the applicator member, usually the roller, is controlled by a doctor blade defining with the applicator surface a gap having the appropriate thickness for the butter layer. The disadvantage of contact buttering is that crumbs can stick to the applicator member and can then clog the gap between the doctor blade and the applicator member, resulting in inaccurate butter application.

The second known method is non-contact buttering in which butter is sprayed or thrown onto the surface of a slice of bread, either from a nozzle through which the butter is pumped or from a spinning disc. With the spinning disc method, softened butter is pumped onto the disc and the effect of centrifugal force flings the butter off the edge of the disc and onto the slice of bread passing beneath the disc. However, current non- contact methods have the disadvantage that not only the exposed bread face but also the crusted edges become covered with the butter so that particularly the front edge of the slice of bread becomes contaminated with the butter.

It is an object of the present invention to provide a method and apparatus for applying coating material only to a selected face, for example the exposed bread face of a bread slice, without inadvertently applying butter to other faces of the article.

Accordingly, one aspect of the present invention provides a method of coating only a selected face of an object without applying coating to an adjacent surfaces, comprising creating relative movement between the object and a mass of coating material moving along a path, providing an acute angle between the direction of movement of the moving mass of coating material and the plane of the selected face to be coated, as the article comes into contact with the coating material, and creating an obtuse angle between the direction of movement of the mass of coating material and the plane of the selected face to be coated, as the article leaves the path of the moving coating material.

A second aspect of the present invention provides apparatus for coating only a selected face of a moving article comprising means for generating a flow of coating material along a path in a first direction, means for moving an object to be coated along a second direction transverse to the first direction so that a first end of said selected face of the object enters the path of the coating material before a second end opposite to the first end of the selected face, means for changing said first direction and/or said second direction as an object is fed through the path of the coating material, such that the direction of flow of the coating material as said first end of the selected face enters the flow is an acute angle such that the flow has a component of movement from said second end towards said first end of the selected face, and for altering said orientation as the second end of the selected face passes through said path of the moving coating material so as to provide that the direction of movement of the coating material has a component of movement from said first end towards said second end of the selected face.

In order that the present invention may more readily be understood the following description is given, only by way of example, with reference to the accompanying drawings in which:- Figure 1 is a schematic side elevation showing a prior art non-contact buttering apparatus; Figure 2 is a similar view showing a bread slice about to enter the curtain of liquid butter emanating from a spinning disc in apparatus according to the present

invention; and Figure 3 is a view showing the same bread slice of Figure 2 as it leaves the curtain of liquid butter.

As shown in Figure 1, the buttering head is a butter-flinging disc which rotates about a horizontal axis and emits a curtain of liquid butter which passes downwardly between the discharge end of a feed conveyor and the entry end of a forwarding conveyor which takes over the task of moving the bread slice after it has left the feed conveyor.

Figure 1 shows the prior art arrangement in which a slice of bread 1 moves towards the downwardly moving curtain 3 of liquid butter being spun off a disc 5 rotating about a horizontal axis 7. The bread slice is being advanced by the feed conveyor comprising a belt 9 passing around two rollers one of which, 11, can be seen in Figure 1, and the bread slice passes off the left hand end of the feed conveyor to pass through the butter curtain 3 and onto the forwarding conveyor comprising a belt 13 passing around two rollers one of which, 15, can be seen in Figure 1.

It will be appreciated that as the leading edge la of the slice 1 enters the curtain 3 that leading edge will pick up butter from the curtain 3, and likewise as the trailing edge lb passes through the plane of the curtain it, too, can be contaminated. The intention is that only the upper surface 1 c should be coated with butter.

One embodiment of the present invention is illustrated in Figure 2 where there are various departures from the conventional apparatus shown in Figure 1. The important aspect of the method of the present invention is, however, that there is an acute angle formed between the direction of movement of the coating material, in this case butter, and the face being coated, in this case the upper face 1 c of the bread slice 1, as the article enters the moving mass of coating material, namely the curtain 3 of butter. Furthermore, as the article leaves the moving mass of coating material the angle formed between the direction of the coating material and the plane of the face being coated should no longer be acute, but should be obtuse.

This re-orientation is achieved in Figure 2 by having the belt 9 of the feed conveyor inclined downwardly at the end near the curtain 3 of butter and also having the rotation axis 7 of the disc inclined to the horizontal but by an angle of inclination which is less than that of the bread slice 1 so that when the bread slice 1 becomes horizontal on arriving on the belt 13 of the forwarding conveyor there is now an obtuse angle formed between the curtain 3 and the trailing edge I b of the bread slice.

The acute angle relevant to the entry of the bread slice into the butter curtain 3 is shown at a in Figure 2 and the obtuse angle relevant to the passage of the trailing edge I b through the curtain 3 is shown at ß in Figure 3.

Although in the embodiments shown in Figures 2 and 3 the angle of inclination of the bread changes with respect to a static direction of the moving mass of coating material (the butter curtain 3) it is alternatively possible for the direction of the moving mass of coating material to be changed relative to a surface to be coated (the upper face 1 c of the bread slice 1) which remains constant. Equally there could be some combination of these two actions, for example by also tilting the angle of inclination of the rotation axis 7 between Figure 2 and Figure 3, or by similar provisions in any other form of the apparatus.

In terms of the mechanics of the apparatus, the inclination of the belt run supporting the bread slice 1 at the point of entry into the butter curtain 3 is achieved by having an additional roller 19 over which the belt of the feed conveyor 9 passes, but with its upper surface lower than the upper surface of the above mentioned roller 11. Alternatively it would have been possible to add, in the apparatus of Figure 1, a small diameter roller to the right of the roller 11 shown in Figure 1, but at a higher level so that again the run of the conveyor belt 9 approaching the curtain 3 is downwardly inclined.

The achievement of the acute angle P in Figure 3 results from the inclination of the rotation axis 7 relative to a horizontally moving upper run of the belt 13 of the forwarding conveyor. This makes for a simple apparatus in that the forwarding

conveyor can be identical to that of the conventional apparatus typified by Figure 1.

However, it is equally possible for the angle of inclination of the bread slice to be such that the leading edge 1 a in Figure 3 is higher than the trailing edge, and then the rotation axis 7 could be maintained stationary and the acute angle P still achieved.

The precise means for applying the liquid butter to the spinning disc 5 are not essential to the present invention as these are well known in the art and need not be changed as a result of the modification to provide the non-contact coating apparatus of the present invention.