GB2174349A - Carriers for use in conveyors - Google Patents

Abstract

A conveyor surface is formed by a plurality of grid carriers 10. The conveyor includes a straight section 12 and a curved or spiral section 14 (only part of which is shown). The conveyor is used to transport loaves whilst they are cooling, and it is important that the distance between adjacent carriers does not exceed a predetermined amount during the straight or curved path. Accordingly each grid carrier is tapered from a central region towards a tip 20 at a common side of the conveyor. Thus the space 18 between the tips 20 decreases as the conveyor travels around the curved path 14, and the gap 22 between the opposite sides of the carriers 10 increases as the conveyor goes around that curved path, but, whilst the conveyor provides a supporting surface, the spaces 18 or gaps 22 do not exceed a predetermined amount either on the straight or curved section. The carriers may be snap-fitted onto projections on the drive chain. <IMAGE>

Description

SPECIFICATION Carriers for use in conveyors The present invention relates to carriers for use in conveyors, and in particular, although not exclusively, to carriers arranged to support loaves of bread after they have been cooked but before they have cooled sufficiently to allow them to be sliced.

In bakeries, bread is continously baked.

After the bread has been baked it has to cool for a period of around two hours before it can be sliced and then packed. If it is attempted to slice the bread too early, before it has cooled sufficiently, the bread tears.

A conveyor is provided to transport the loaves in rows of six while the bread cools. In order to reduce the space occupied by the conveyor, which may be carrying 16,000 loaves or more at any one time, the conveyor includes one or more spirals.

The loaves are supported on a plurality of metallic grid carriers each of whose upper surface comprises a number of spaced parallel rods extending in the direction of travel of the conveyor, and upon which the loaves can rest. The rods of each grid are connected together by cross members extending beneath the rods and spaced from the ends of the rods. Each grid is attached on its underside in its central region to a pendant by a pair of nuts and bolts. The pendants extend from an endless chain which is driven to cause the movement of the conveyor. When the conveyor is travelling in a straight line, adjacent grid carriers are spaced apart slightly, but when the conveyor travels around a bend the parallel rods on the inside of the bend are caused to move between the parallel rods of adjacent carriers.

As the grid carriers are made of metal they are expensive and time consuming to manufacture. Furthermore, the ends of the parallel rods tend to bend downwardly after prolonged periods of use to allow an uneven surface to be presented to the loaves.

As the parallel rods of adjacent carriers overlap each other on the inside of bends, and as the rods are spaced fairly close to each other, the rods of adjacent carriers can snag on each other resulting in damage to the carriers. This damage sometimes causes the ends of the rods to extend upwardly out of the general plane of the supporting surface of the conveyor to cause loaves to be pronged and damaged.

When it is desired to change a damaged grid carrier, it is necessary to stop the conveyor, and therefore to stop the whole baking production line, before the relatively inaccessible nuts and bolts can be removed, the damaged carrier replaced and the nuts and bolts secured again.

According to one aspect of the present invention, in a carrier arranged to be used as part of a support surface of a conveyor, the extent of the carrier at one side is less than its extent at the other side.

According to a further aspect of the present invention, a conveyor includes a support surface defined by a row of carriers each extending across the conveyor, the extent of each carrier in the intended direction of travel being less at one side of the support surface than it is at the other side. With such a conveyor, where the carriers are supported from beneath the support surface in a central region, the gaps between adjacent carriers at either side may never exceed a predetermined amount both when the conveyor is travelling in a straight line and when the conveyor is travelling around a curved path with the one side of the carriers being on the inside of the curved path. The extent of the one side of the carrier in the intended direction of travel may be reduced from the extent of the other side by between 15 and 45% or in the region of 30%.

The extent of the carriers in the direction of travel may decrease from a central region towards the one side and the extent in the direction of travel may taper inwardly from a central region towards the one side.

The periphery of each carrier may be arranged to provide a continuous part of the support surface.

The support surface provided by the coneyor may be generally flat.

Adjacent carriers may be arranged to occupy separate spaces from each other along the length of the support surface whereby the carriers do not overlap each other.

The carriers may be capable of being mounted on the conveyor with the one side of the support surface being located at a selected side of the conveyor.

According to another aspect of the present invention, in a carrier arranged to be used as part of a support surface of a conveyor, the carrier is adapted to be secured to a conveyor by urging a connecting portion of the carrier over a projection from the drive means of the conveyor.

According to a further aspect of the present invention, in a carrier arranged to be used as part of a support surface of a conveyor, the carrier is adapted to be secured to a projection from the drive means by a snap-fit.

The securing of the carrier to the projection from the dive means by urging it towards the projection or by providing the snap-fit allows the carrier to be quickly and easily secured to the drive means. Thus replacement of a damaged carrier can readily be made, and assembly of a plurality of carriers onto a coneyor is a simple operation.

The carrier may include a spring member or memb rs arranged to co-operate with a recess or opening in a projection from the drive means.

The carrier may be adapted to be removed from a projection from a drive means to which it is secured by pulling the carrier away from the projection. With this arrangement, it may not be necessary to stop a conveyor whilst replacing a damaged carrier.

According to a further aspect of the present invention, a carrier arranged to be used as part of a support surface is formed by injection moulding plastics.

The carrier may be of grid form.

It will be appreciated that the present invention includes any combination of the above described features.

The invention may be carried into practice in various ways, but one embodiment will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a plan view of a grid carrier; Figure 2 is a plan view of a plurality of grid carriers arranged in a row and shown with a straight and a curved section, and Figure 3 is an exploded perspective view showing the connection between the underside of the carrier and a projection from the drive means.

The grid carriers 10 shown in the drawings are for use in a cooling conveyor on which recently baked hot bread is conveyed for around 2 hours until it has cooled sufficiently to be sliced without tearing. The baking of bread is a continuous process and therefore, rather than being able to store the bread whilst cooling, it is necessary to keep it on the move which results in the conveyor being extremely long. In order to reduce the area occupied by the conveyor it is frequently spiralled.

Each carrier 10 is arranged to support six loaves across its width. In order that the loaves do not tend to fall between adjacent carriers, or interfere with or be unduly affected by the movement which will occur between carriers, the carriers are spaced fairly close together. However, it is necessary that some gap b tween adjacent carriers be provided as adjacent edges move towards and away from each other.

In Figure 2 the carriers are shown travelling along a straight section 12 of the conveyor and a curved section 14. Each carrier 10 is tapered inwardly to one side of the carrier and isof constant width at the other side of the carrier. The tapered portions of adjacent carriers are arranged to be on one side side 16 of the conveyor such that, as the carriers travel along the straight section, there is a considerable space 18 between the tips 20 of the tapered portions relative to the fairly narrow gap 22 between the portions of constant width.

The carriers are supported and driven from beneath their central region. Thus the distance between the central regions of adjacent carriers is fixed. As the carriers travel onto the curved section 14, the adjacent tips 20 are moved towards each other, reducing the space 18, and the gap 22 is increased.

The centres of adjacent carriers are spaced apart by 152.4 mm, and the gap between the edges at the centre of the carriers is 7.4 mm.

The width of the tips 20 is 100 mm and the space 18 between adjacent tips is 52.4 mm on the straight section and around 9 mm on the curved section. The gap 22 between the edges of adjacent carriers at the opposite side to the tips 20 is around 51 mm on the curved section. The radius of the curved section through the centre line of the carriers is 1524 mm.

The construction of a carrier is shown in detail in Figure 1 and comprises an injection moulding of plastics with a grid forming the support for the loaf. The grid includes a peripheral strut 24 with intermediate struts 26 providing strength and additional support for the loaves. The upper surface of the grid may be formed with dimples or reverse dimples to improve the grip on the loaves and help prevent them from sliding on the carriers.

Extending downwardly, and formed integrally therewith from a strut 28 extending across the centre of the carrier is an attachment housing 30, shown in greater detail in Figure 3.

The housing 30 includes a downwardly opening socket 32 which is arranged to slide over a pendant 34. The pendant extends upwardly from an endless chain (not shown) which is used to drive the conveyor. The housing 30 may be retained on the pendant by any suitable means and in the illustrated embodiment a pair of spring loaded balls 36, shown diagrammatically, project into the socket and are arranged to co-operate with a pair of openings 38 extending through the pendant. The co-operation of the balls with the pendant is such that as the carrier is pushed onto the pendant, contact between the upper edge of the pendant and the balls causes the balls to be pushed back against the spring force until they are flush with the wall of the socket. The balls remain pressed against the pendant until they are aligned with the openings 38, when they spring out into the openings. To remove the carrier from the pendant it may b possible to pull the carrier off, contact between the balls and the edge of the openings causing the balls to be pushed back into the wall of the socket. Alternatively, the balls may be manually retracted from the openings and the carrier lifted off. In any event, it is necessary that the carriers are retained on the pendants with some force as, on the return run of the conveyor they hang downwardly from the pendant.

The arrangement illustrated in Figure 2 is suitable where all of the turns in the conveyor are in the same direction as the curved section. However, the same carrier could also be used on a conveyor where the turns are in the opposite direction simply by mounting all of the carriers the other way round.

Claims (16)

1. A conveyor including a support surface defined by a row of carriers each extending across the conveyor, the extent of each carrier in the intended direction of travel being less at one side of the support surface than at the other side.

2. A conveyor as claimed in Claim 1 in which adjacent carriers are spaced from each other at least while they define the support surface.

3. A conveyor as claimed in Claim 1 or Claim 2 in which the extent of one side of each carrier in the intended direction of travel is reduced from that extent of the other side of the carrier by between 15 and 45%.

4. A conveyor as claimed in Claim 3 in which the extent of one side of the carrier in the intended direction of travel is reduced from that extent of the other side in the region of 30%.

5. A conveyor as claimed in any of Claims 1 to 4 in which the extent of each carrier in the direction of travel decreases from a central region towards the one side.

6. A conveyor as claimed in Claim 5 in which the extent of each carrier in the direction of travel tapers inwardly from a central region towards the one side.

7. A conveyor as claimed in any of Claims 1 to 6 in which the periphery of each carrier provides part of the support surface.

8. A conveyor as claimed in any of Claims 1 to 7 in which the support surface provided by the conveyor is generally flat.

9. A conveyor as claimed in any of Claims 1 to 8 in which the support surface provided by the carriers curves in one direction only relative to the intended direction of travel.

10. A carrier arranged to be used as part of a support surface of a conveyor, the extent of the carrier at one side being less than its extent at the other side.

11. A carrier arranged to be used as part of a support surface of a conveyor, the carrier being adapted to be secured to the conveyor by urging a connecting portion of the carrier over a projection from the drive means of the conveyor.

12. A carrier arranged to be used as part of a support surface of a conveyor, the carrier being adapted to be secured to a projection from the drive means of the conveyor by a snap-fit.

13. A carrier as claimed in Claim 11 or Claim 12 including a spring member or members arranged to cooperate with a recess or opening in a projection from the drive means.

14. A carrier as claimed in Claim 11, 12 or 13 adapted to be removed from a projection from a drive means to which it is to be secured by pulling the carrier away from the projection.

15. A carrier substantially as herein described with reference to, and as shown in Figures 1 to 3 of the accompanying drawings.

16. A conveyor including a carrier substantially as herein described with reference to, and as shown in Figures 1 to 3 of the accompanying drawings.