GB2120517A - Wafer spreader machine - Google Patents

Abstract

The wafers (1) to be spread are conveyed by conveyor bands (7, 10) beneath the spreader head (2) of a wafer spreader machine. A support roll (9), which lies beneath the spreader head, has both conveyor bands (7,10) passing round it. The support roll can be lowered by pivoting about 16 on movement of cylinder (17) in order to keep individual wafers out of engagement with the spreader head. <IMAGE>

Description

SPECIFICATION Wafer spreader machine The invention relates to a wafer spreader machine having a spreader head beneath which wafers, to be spread with a filling by a contact method, are conducted through in succession, and having at least one endlessly circulating flexible conveyor element carrying the wafers, which is lowerable at least in the region beneath the spreader head in the passage of individual wafers which are intended as cover wafers of a multilayer wafer block.

In the production of multi-layer wafer blocks which consist of a plurality of wafers and interposed layers of filling, for example cream, the individual wafers are successively spread with the filling by a constant method. The spreader head used for this purpose possesses for example a spreader cylinder driven contrary to the direction of through-flow of the wafers, which takes the filling from a reservoir and spreads it on the upper sides of the wafers.

The uppermost wafer of each wafer block, the cover wafer, receives no spreading of filling. In order to avoid the considerable extra expense of labour in having to feed this cover wafer individually, various measures have already been taken to bring the spreader head out of engagement with the cover wafers as they run past.

In a known method which has also already been carried out in practice (German Published Specification 25,37,711) the spreader head is tiltable so that the spreader cylinder can be brought out of engagement with the cover wafer running through beneath it. However the pivotable mounting of the spreader head necessary for this purpose involves constructional difficulties, on account of the weight of the reservoir connected therewith and the filling contained in it. On account of the great masses to be moved in that case, limits are set to an increase of the working speed.

In a wafer spreader machine of the initially stated kind (Austrian Patent Specification No.

245,514) too, relatively heavy masses have to be moved in a constructionally expensive manner, opposing an increase of the working speed. In this known wafer spreader machine the circulating conveyor element carrying the wafers is a conveyor belt which is mounted in a frame which is lowerable at the charging end in order according to choice to bring individual wafers, which are intended as cover wafers, out of engagement with the fixedly arranged spreader head. At every stroke in this case a considerable part of the entire conveyor equipment must be lowered and raised again.

It is therefore the object of the invention to provide a wafer spreader machine of the initially stated classification in which the masses to be moved in the lowering of the conveyor element are so small that a substantial increase of the working speed is rendered possible.

In accordance with the invention this problem is solved in that the endlessly circulating conveyor elements are conveyor bands arranged parallel and with spacing from one another, in that a group of conveyor bands lying, seen in the conveying direction, before the spreader head and a group of conveyor bands lying behind the spreader head loop around a common support roll arranged beneath the spreader head, and in that the support roll is mounted to be lowerable.

For the lowering of the conveyor element in the region beneath the spreader head in this case only the support roll with its associated mounting and relatively short sections of the two groups of conveyor bands are moved. The mass of these components which must be moved is small, so that the lowering movement and subsequent raising movement can be carried out very rapidly and render possible a rapid progress of work.

Compared with the known conveyor belts the conveyor bands lying side by side at intervals have the advantage that no residues of filling remain lying on them, but drop through between the bands. Therefore even a wedge of filling building up before the front edge of the wafer at the beginning of the spreading operation causes no difficulties, because it drops through between the conveyor bands.

To avoid such a wedge of filling material in front of the front edge of the wafer, in a known wafer spreader machine having the initially stated classification features (German Pub. Sp.

29 41 318) a raisable support roll was provided beneath the spreader head, the vertical movement of which roll however served only to raise the conveyor belt carrying the wafer further, after the beginning of the spreading operation, in order thus to prevent the formation of a wedge of cream before the front edge of the wafer. Although this support roll carried out a lowering movement after the termination of a spreading operation, the described lowering of the frame of the conveyor belt also had to be provided in this case in order to bring the individual wafers intended as cover wafers out of engagement with the spreader cylinder. The lowering movement of the support roll also would be unsuitable for this purpose because, on account of the necessary tension of the conveyor belt, lowering beyond the stretchedout position was not possible.However above this stretched-out position no sufficient lowering stroke was available to bring the wafer out of engagement with the spreader cylinder, because otherwise the spreading of the wafers would have to take place in such a highly raised position of the support roll that the wafers would then be broken under the weight of the applied filling on the far side of the apex point thus formed in the conveyor belt, on account of lack of support by the conveyor belt.

In contrast thereto, the division of the conveyor element in accordance with the invention into two mutually adjoining groups of conveyor bands which overlap one another only in the common looping around the support roll renders possible a lowering out of the stretched-out position of the conveyor bands. The spreading of the wafers takes place on a conveyor support which is running through rectilinearly, having no apex point and no lowering, so that a uniform supporting of the wafers is ensured even after they have passed the spreader head.

A departure from this rectilinear supporting of the wafers takes place only when the support roll is lowered. The single wafer then conveyed through beneath the spreader head is not then spread and therefore remains without additional loading by the filling. This single wafer is therefore not endangered even if the supporting by the conveyor device is not wholly uniform.

The number of the conveyor bands which support the wafer before and after the spreader head can be made relatively low because the wafer is supported at the position of highest loading, namely directly beneath the spreader head, by the conveyor bands of both groups, which overlap there, and by the support roll at the same time.

Advantageous developments of the idea of the invention are the objects of sub-claims.

The invention will be explained in greater detail below by reference to an example of embodiment which is represented in the drawing, wherein:- Figure 1 shows a wafer spreader machine in a simplified, vertical longitudinal section, the support roll being situated in its upper position, Figure 2 shows a longitudinal section corresponding to Figure 1, but with the support roll situated in its lowered position, Figure 3 shows a plan view of the wafer spreader machine according to Figures 1 and 2, the spreader head being omitted, and Figure 4 shows an enlarged partial section along the line IV--IV in Figure 1.

The wafer spreader machine as illustrated serves to provide wafers 1 in succession with a spreading of a filling, for example cream, before the wafers are stacked one upon the other to form a wafer block. The spreader machine comprises a spreader head 2 which accommodates a store of filling 4 in a reservoir 3. Beneath the reservoir 3, which is open at the bottom, there are arranged a driven spreader cylinder 5 and a counter cylinder 6.

The wafers are brought in on a group of endlessly circulating conveyor bands (from right to left in Figure 1) arranged before the spreader head 2, seen in the direction of through-put. The conveyor bands 7 run at the one end over a reversing roller 8 and at the other end over a support roll 9 which is situated beneath the spreader cylinder 5.

Seen in the conveying direction, behind the spreader head 2 there lies a further group of conveyor bands 10 which likewise loop around the support roll 9 and are conducted over a drive roll 11. The direction of rotation of each of the rolls is indicated in Figure 1 with an arrow. It is seen that the spreader cylinder 5 rotates contrarily of the direction of movement of the wafers 1. In this action the spreader cylinder 5 applies a layer of the filling, taken up on its circumference, on to the top of the wafer 1. In front of the support roll 5 a presses roll 12 is provided; after the spreader head 2 a spiked roll 1 3 is situated.

It can be seen from Figure 3 that to each conveyor band 7 of the first group there are allocated two conveyor bands 10 of the second group which lie on both sides of the conveyor band 7 in the common looping around the support roll 9. Therefore the number of conveyor bands 10 of the second group is twice as great as that of the conveyor bands of the first group.

While the reversing rollers 8 and 11 are mounted in a spreader machine frame 14 which also carries the spreader head 2, the support roll 9 is mounted in a frame 1 5 which is pivotable about a pivot spindle 1 6 lying at a distance from the support roll 9. A pressure-medium-actuated cylinder 17 acts upon an extension 1 5a of the frame 1 5 and on actuation pivots the frame 1 5 into the position as shown in Figure 2, so that the support roll 9 is lowered in comparison with the position as shown in Figure 1. The wafer 1' then passing through remains out of engagement with the spreader cylinder 5 and therefore receives no spreading of filling. This wafer 1' serves as cover wafer of a wafer block.

Support surfaces 1 8 and 1 9 supporting the conveyor bands 7 and 10 respectively are fitted one before and one behind the support roll 9 on the pivotable frame 15, the support surface 1 8 arranged between the support roll 9 and the pivot spindle 1 6 having a ramp 1 8a on the arrival side of the conveyor bands 7. In the lowered position (Figure 2) this ramp 1 spa facilitates the running of the conveyor bands 7 up on to the support surface 18, because in the pivoting movement of the frame 1 5 the support roll 9 is lowered more than the support surface 1 8.

In Figure 4 it is shown that the support roll 9 possesses guide grooves 20 for the conveyor bands 7 and 10. In the example of embodiment as represented the guide grooves 20 are so deep that the surface of the support roll 19 between the conveyor bands 7, 10 forms an additional support for the wafer 1 when loaded by the spreader cylinder 5.

Immediately beneath the support roll 9 a scraper 21 secured to the pivotable frame 1 5 is arranged and scrapes off residues of the filling.

Comb-type scrapers 22 are also provided on the conveyor bands 7 and 10 to scrape off filling residues.

On both sides of the group of conveyor bands 10 there are guided bands 1 Oa which are in frictional engagement with a friction wheel 1 3a which is seated on the shaft of the spiked roll 1 3 and drives the latter (Figure 4).

The surface of the support roll 9 can also have an elastic, for example rubber, coating in order to improve the entraining of the wafers 1.

Claims (8)

1. Wafer spreader machine having a spreader head beneath which wafers, to be spread with a filling by a contact method, are conducted through in succession, and having at least one endlessly circulating flexible conveyor element carrying the wafers, which is lowerable at least in the region beneath the spreader head in the passage of individual wafers which are intended as cover wafers of a multi-layer wafer block, characterised in that the endlessly circulating conveyor elements are conveyor bands arranged parallel and with spacing from one another, in that a group of conveyor bands lying before the spreader head, in the conveying direction, and a group of conveyor bands lying behind the spreader head loop around a common support roll arranged beneath the spreader head, and in that the support roll is mounted so as to be lowerable.

2. Wafer spreader machine according to Claim 1, characterised in that the support roll is mounted in a frame which is pivotable by means of a pivot drive about a pivot spindle lying at a distance from and parallel to the support roll.

3. Wafer spreader machine according to Claim 1, characterised in that the support roll possesses guide grooves for the conveyor bands.

4. Wafer spreader machine according to Claims 2 and 3, characterised in that a scraper secured to the pivotable frame is arranged directly beneath the support roll.

5. Wafer spreader machine according to Claim 2, characterised in that support faces supporting the conveyor bands are arranged on the pivotable frame one before and one behind the support roll.

6. Wafer spreader machine according to Claim 5, characterised in that the support face arranged between the support roll and the pivot spindle of the frame has a ramp on the arrival side of the conveyor bands.

7. Wafer spreader machine according to Claim 1, characterised in that with each conveyor band of the group arranged before the support roll there are associated two conveyor bands, arranged offset at a short distance on both sides, of the group lying behind the spreader head.

8. Wafer spreader machine substantially as herein described with reference to the drawings.