GB2215977A - Restricting height of baked products - Google Patents

Description

2215977 METHOD_AND_APPARATUS_FOR_PRODUCING_BAKED This invention relates to

a method and apparatus for producing baked products of a predetermined height and to apparatus for restricting the height of such products. The method and apparatus are particularly applicable to the manufacture of products baked in moulding- tins which are to be packaged or further processed by a machine.

Various types of baked products are cooked in moulding tins in order to achieve a defined size although, in the absence of further aids, this defined size is restricted to their lateral dimensions only. A known method of achieving a defined height for baked prod_Vts is by covering the moulding tins with suitable sheet metal lids during the entire baking process. Although this covering can be effected quite easily in any baking oven, it does require additional working processes which must be carried out either by hand or using expensive manipulators.

Another known method is to convey the lids in the form of a closed chain through a continuous baking oven, out of the other end and back again with the chain then being automaticilly placed at the start of the baking process on the moulding tins, which are similarly conveyed as a chain through the baking oven, and removd again at the end of the process. The disadvantage here is the required rigid chain conveyance of the moulding tins since this can only be achieved in special baking ovens. -If it is omitted, the moulding tins and lid chain may become unsynchronised. Additional problems may also arise if the oven is to be used for batch quantities with or without covering.

All these solutions have the additional disadvantage that they are suitable only for products baked in moulding tins so they can be unevenly browned at the end of the baking process. It is also known to limit the height of unmoulded baked products such as puff pastry by guiding a plastic belt, which rests on the pieces of dough, over rollers, through a continuous baking oven, out of the other end and then back again.

The disadvantage of this method is the need for a special construction and functional limitation of the oven.

Finally, another known method comprises covering the moulding tins during the continuous baking process at most from the beginning to 60% of their passage through the oven, this being achieved by means of a flexible perforated covering belt which is disposed in the baking chamber above the continous belt and is guided over rollers. Although this solution does not cause any problems with synchronisation and enables uniform browning of the baked products, it does nevertheless necessitate some adaptation, especially to the height of the baking chamber, since the diameter of the guide is rollers cannot be arbitrarily small. If the option of operating the oven with or without covering is required, this height must be even greater. Also, because of uneven areas in the continuous belt, increased tolerances in the height may arise.

It is an object of the invention to permit the flexible baking of various types of baked products of a predetermined defined height of improved quality and at low cost.

4 The purpose of the invention is to achieve automatic optional limitation of the height of baked products through the use of height-restricting means variably-at most from the start up to 60% of the baking process, this requiring - with a low height restriction tolerance - a low installation height above the baking material.

This purpose is achieved in accordance with a preferred method of the invention whereby the baking material is introduced without height-restricting means into the baking oven and locally and/or time-differentiated phases with height limitation and phases without height limitation are run through alternately during the baking process.

In an advantageous form of the invention, the baking material continuously or intermittently performs a relative movement with regard to the height-restricting means.

In a further form, the baking material may comprise pieces of dough inserted in moulding tins.

In a preferred apparatus for performing the method of the invention, the apparatus comprises a continuous baking oven having a baking chamber through which a continuous belt runs and dimensionally stable limiting elements disposed in the baking chamber above the continuous belt which can be lifted or lowered positively and automatically in a locally and/or time differentiated manner and are positively or freely movable in the opposite direction and/or direction of passage.

According to a first embodiment, the dimensionally stable limiting elements are rotatable, cylindrical rollers which are disposed horizontally with their axis aligned in each case across the direction of passage.

The rollers may be constructed in such a manner that the axial extension of a roller corresponds at least to the width of the continuous belt. In a further form, a plurality of rollers of the same diameter whose faces are in contact may be disposed across the width of the continuous belt, or the rollers may have a flexible covering and be stabilised by discoid support elements.

6 For guidance, each roller may have a central bore through which a laterally movably supported rod is guided having a maximum cross-sectional dimension substantially smaller than the diameter of the bore of the associated roller.

When the rollers extend over the full width of the conveyor, they may be laterally guided in elongated holes having their greater extension disposed vertical7ly. This variation of the apparatus of the invention is not confined to continous baking ovens with a continuous belt but with a positive intrinsic horizontal movement may also be disposed in the baking chamber of other baking ovens.

According to a second embodiment of the apparatus of the invention for continuous baking ovens, the dimensionally stable limiting elements are rectangular covering elements which are guided in a manner permitting lateral lifting and lowering and are positively movable at least in the opposite direction to the direction of passage.

7 The covering elements may be disposed on one plane and may be connected to one another as well as be adjacent to one another in a gap-free manner.

The covering elements advantageously extend over the full width of the continuous belt and/or comprise frames which extend over the full width and whose enclosed surfaces are closed by single elements. 10 The sing7le elements may be flexibly mounted on the frames of the covering elements and/or may be gridlike. During the baking process, the dimensionally stable 15 limiting elements are applied repeatedly onto the baking material and lifted off again and this action can be assisted or exclusively caused by a continuous or intermittent relative movement between the two. As a result, the upward-curving surface of the baking 20 material is pushed down again by the limiting elements being applied onto it and is gradually moulded into a flat surface.

There is also the possibility of continuous relative movement in the first embodiment of the apparatus of the invention. Here, the rollers are so disposed during use that the distance of the lowest generating line of the roller from the continuous belt in the lowest position corresponds to the required height of the baked products. If these products are located in moulding tins, the lowest generating line has, at most, the height of the moulding tins as a clearance between it and the continuous belt and is raised by the moulding tins as they pass through. The differential surface elements of the generated surface which are covered by this generating line are in the process applied onto the baking material. With the movement of the baking material, the generating lines move with a component in the direction of passage, are simultaneously moved upwards, are guided back after rolling off and are once more applied onto other points of the baking material. With flexibly designed rollers, any slightly uneven areas, which can arise particularly with moulding tins, are compensated for.

The laterally movably held struts or lateral guides permit additional positive movements in a vertical direction to take the rollers out of operation and horizontally in or counter to the direction of the continuous belt. In ovens without a continuous belt, this intermittent horizontal movement of the rollers leads to production of the relative movement with regard to the baking material.

In the second embodiment of the apparatus of the invention, an intermittent relative movement between the baking material and the dimensionally stable limiting"elements is required. During use, the covering elements are placed by way of the guides located laterally outside of the continuous belt onto the baking material, are moved forward with it and using a pilgrim-step system are lifted off the baking material, are moved positively counter to the direction of passage and, in this set-back position, are once more placed onto the baking material. In so doing, all the surface elements simultaneously perform a loop movement corresponding to that of the first embodiment.

IF the baking material is in moulding tins, the forward - movement of the covering elements may be effected freely by their proper motion or positively but in the case of freely formed baking material, this movement may only be positively effected. With the covering elements in the form of frames with flexibly mounted single elements, any slightly uneven areas, such as can arise in particular with moulding tins, are compensated. If the covering elements are left in the upper position, the device is put out of operation.

In all embodiments, the repeated application of the dimensionally stable limiting elements has the effect of compensating the height restriction tolerance, particularly when applied in a different position; also in the case of grid-like limiting elements, the crusts of the baked products do not have any texturing caused by the height restriction measures.

The height-restricting device can easily be put out of operation.

The option of height restriction during part of the baking process only is retained. By putting some of the limiting elements out of action or making them additionally operative, it is possible to vary the region in continuous baking ovens where the baking process involves height restriction so that the use of ( -1 height-restricting means can be adapted to suit the type of products being baked.

The limiting elements permit structural sectionalization of the complete device which, with the additional factor of the low installation height, means that existing ovens can be easily refitted.

The invention will now be described, by way of example only, wi:th reference to the description hereafter of preferred embodiments thereof, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a partial longitudinal section (not to scale) of a continuous baking oven fitted with a device according to the invention provided with rollers; and Figure 2 is a partial longitudinal section (not to scale) of a continuous baking oven fitted with a device according to the invention provided with covering elements.

The device shown in Figure 1 comprises a body 2 which is disposed in a baking chamber 1 and in which are disposed a plurality of dimensionally stable limiting -1 12 elements 3 comprising cylindrical rollers with axes extending transversely to the direction of the passage of baking material 4 in moulding tins over the full width of continuous belt 5. The rollers are disposed only in the first half of the baking chamber 1. The rollers 3 have central bores and are mounted on axles of circular cross-section which are held laterally in the body 2 and each has a substantially smaller diameter than that of the associated bore in the roller,-the maximum distance between the lowest generating line of the rollers in their lowest position and the continuous belt 5 corresponding to the height of the moulding tins. Slight differences in height of the moulding tins are compensated for by the play in is the roller mountings.

During the baking process, the baking material 4 located in the moulding tins on the continuous belt 5 is moved continuously towards the rollers 3. As a result, the rollers are slightly raised and roll off over the upper edges of the moulding tins. The dead weight of the rollers gradually and plasto-elastically moulds the surface of the baking material. which curves up over the upper edges of the moulding tin as it 13 expands into a flat surface which is parallel to the base of the moulding tin. The lowest generating lines of the rollers move, as a result of rolling over the edges of the moulding tins, in.the direction of the continuous belt 5 which, in a continuation of the rotary movement, results in raising of the generating line, movement counter to the direction of passage on the upper side of the roller, and finally renewed contact with other moulding tins. Because of the movement of the moulding tins, the individual moulding tins pass through alternating phases with and without height restriction during the baking process. As a result of positive raising, ie. increasing the distance between some or all of the rollers and the is continuous belt, there is the option of adaptation to the type of baked product or operation without height restriction. Since the movements during operation are automatically effected, in this embodiment it is possible to dispense with an additional drive for the rollers.

In the device shown in Figure 2, the dimensionally stable limiting elements 3 are rectangular covering elements which extend over the full conveyor width and 14 are closely adjacent to.one another. Each covering element 3 is provided at both side edges with two supports 6 and is stabilised by a frame. The supports 6, located on bearing surfaces 7, allow the covering elements to move in the direction of movement of the continuous belt 5. On either side, runner rails 8 are disposed over the bearing surfaces 7 parallel to these and at the same distance and have recesses at specific points. The supports 6 of the covering elements 3 can be rais6d through these recesses and they can move between the recesses when the supports 6 are located on the runner rails 8. Wedges 9 disposed below the recesses of the runner rails 8 are used to raise covering elements. Hinged flaps 10 disposed in an extension of the runner rails bridge the recesses between the rails and the wedges 9.

The covering elements are connected to one another by rods 11 and are positively moved in both directions by a control gear motor 12. For movement in the direction of the conveyor 5, the covering elements move in synchronism with the baking material 4 in the moulding tins through the baking chamber, touching the upper edges of the moulding tins. As the movement continues, - the lateral supports 6 of the covering elements are raised by the wedges 9 and thus removed from the moulding tins. Once the flaps 10 have been passed, the control gear motor 12 is reversed. The covering elements, with their lateral supports 6 located on the runner rails, are rapidly guided back and lowered again onto the moulding tins when the supports 6 reach the recesses. When the control gear motor reverses again, the cycle repeats itself.

As a result of the intermittent movement of the covering elements, the individual moulding tins pass through alternating phases with and without height restriction during the baking process.

In this embodiment, it is possible to use the oven without height restricting means by leaving the covering elements on the runner rails.

With careful design, the installation height required above the baking material can be kept particularly low.

1 - 16 cl

Claims (23)

1. A method for producing baked products of a predetermined height and uniform browning in a baking oven comprising introducing the baking material into the oven and alternatively applying height-restrictive means to the upper surface of the expanding baking material during the baking process.

2. A method according to claim 1, wherein the baking material performs a continuous or intermittent relative movement with regard to the height-restricting means.

3. A method according to claim 1 or 2, wherein the baking material comprises pieces of dough inserted in moulding tins.

4. Apparatus for restricting the height of baked products in a continuous baking oven comprising a baking chamber, a continuous belt running through the chamber, height-rest-ricting means located above the 17 belt oven up to 60% of the initial path of the belt through the oven, the height-restricting means comprising dimensionally stable limiting elements disposed in the baking chamber above the continuous belt openable to be lifted and lowered positively and automatically in a locally and/or time-differentiated manner, said elements also being positively or freely movable in the opposite direction and/or the direction of travel of the belt.

5. Apparatus according to claim 4, wherein the dimensionally stable limiting elements are rotatable, cylindrical, vertically adjustable rollers which are disposed horizontally with their axis aligned in each case across the direction of travel of the belt.

6. Apparatus according to claim 5, wherein each roller extends at least across the width of the continuous belt.

7. Apparatus according to claim 5, wherein a plurality of rollers of the same diameter, whose faces are in contact, are disposed across the width of the continuous belt.

18

8. Apparatus according to any one of claims 5 to 7, wherein the rollers have a flexible covering and are stabilised by means of discoid support elements.

9. Apparatus according to any one of claims 5 to 8, wherein each roller has a central bore through which a laterally held rod is guided having a maximum cross-sectional dimension substantially smaller than the diameter of the bore of the roller.

10. Apparatus according to any one of claims 5, 6 or 8, wherein the rollers are directly guided laterally in vertically arranged slots.

is

11. Apparatus according to claim 4, wherein the dimensionally stable limiting elements are rectangular covering elements which are guided to allow lateral lifting and lowering and are movable at least positively in the opposite direction to the direction of passage.

12. Apparatus according to claim 11, wherein the covering elements are coplanar and are connected to one another.

19 -

13. Apparatus according to claim 11 or 12, wherein the covering elements extend over the full width of the continuous belt.

14. Apparatus according to any one of claims 11 to 13, wherein the covering elements comprise frames which extend over the full width of the continuous belt and whose enclosed surfaces are closed by means of single elements.

is. Apparatus according to claim 14, wherein the single elements are flexibly mounted on the frames of the covering elements.

16. Apparatus according to claim 14 or 15, wherein the single elements are grid-like.

17. Apparatus for restricting the height of baked products in a baking oven, in particular using height-restricting means openable at most from the beginning to 60% of the baking process, rotatable cylindrical rollers being disposed horizontally in the baking chamber above the baked products with their axis aligned across the horizontal direction of movement, said rollers being positively and automatically capable of lifting and lowering in a locally and/or time-differentiated manner and being positively horizontally movable.

18. Apparatus according to claim 17, wherein the axial extension of a roller is adapted to the width of the baking chamber.

19. Kpparatus according to claim 17, wherein a plurality of rollers whose faces are in contact are disposed in the width extension of the baking chamber.

is

20. Apparatus according to any one of claims 17 to 19, wherein the rollers have a flexible covering and are stabilised by discoid support elements.

21. Apparatus according to any one of claims 17 to 20, wherein each roller has a central bore through which a laterally held rod is guided whose greatest cross-sectional dimension is substantially smaller than the diameter of the bore of the associated roller.

1 - 21

22. Apparatus according to any one of claims 17, 18 or 20, wherein the rollers are directly guided laterally in vertically arranged slots.

23. A method for producing baked products of a predetermined height substantially as herein described with reference to the accompanying drawings.

Published 1989 atThePatentOMoe, State House, 68171 High HoIboMIoondonWClIn 4TP. Further opples maybe obtalned&om Mlepatent0fam. SWas Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Crzy Kent, C4)IL 1/87