GB2164018A - Vacuum head for transporting sheet material - Google Patents

Abstract

This invention relates to a vacuum head for the transportation of sheet material 11, such as a sheet made from pastry, which tends to have fissures or tear easily. The head which is used preferably in a pasty making machine comprises a number of compartments 2, 8 separated by airtight walls and a material contacting face 3 having apertures 5. The head is also provided with a cutting edge 6 and the compartments are connected to a source of suction and air pressure. In operation the head cuts out a portion of the material from a continuous sheet made on the machine whilst suction is applied to the head. The latter then transports the portion of the material to a station in the machine where the portion is released by the head by replacing suction with air pressure. The portion is then processed further into a pasty, by the provision of a filling and sealing of the edges of the portion preferably with preheated dies. <IMAGE>

Description

SPECIFICATION Sheet material handling machine This invention relates to a vacuum head for cutting and facilitating in the removal of portions of pastry from continuous sheets of the material and to a pastry making machine incorporating the head.

In bakeries producing pasties including pies and the like, sheets of pastry are required to be rolled out, cut, formed into a desired shape, filled and sealed. Machinery exists for the performing of some of these operations, but limited success has been achieved in the development of a machine capable of performing all of these operations automatically without any intervening manual steps.

One of the more successful machines for carrying out all these steps automatically was developed by the instant applicant and this comprises means for producing a continuous sheet of material, and a station at which portions were cut from the sheet material. The portions were then transferred to a second station by a cutting head provided with suction means whereby the head cuts a portion from the sheet material, lifts the cut portion and transfers it to a second station for further processing. When the cutting head reaches the second station the suction is replaced by air pressure which causes the portion to be released from the head which then returns to the first station to repeat the cycle of operations.

One of the main difficulties confronting the development of a satisfactory automatic machine relates to the removal of portions of pastry from a continuous sheet of the material and transferring the portion by a vacuum lifting head to some other station for further processing. We found that even when a vacuum corresponding to 28 inches of water was employed there was a tendancy for the head to drop the portion of pastry or for the portion to peel away at least partially from the head.

The problem is especially acute with short pastry.

In either case the efficiency of the machine which is intended to make articles of pastry at high speed is likely to be impaired seriously and the machine can readily be prevented completely from functioning.

Whilst the scope of this invention is not to be limited by any theory we have discovered that a possible cause of difficulty stems from the character of pastry sheeting which has been made by rolling out pastry. This material has low tensile strength. It has also low cohesive properties and tends to incorporate fissures or perforations which have the effect of permitting ingress of air into the cutting head. As a result the vacuum within the head is reduced sufficiently to prevent the head from picking up or retaining hold satisfactorily of a cut portion of pastry.

This invention seeks to provide a device which is capable more reliably of transporting sheet material.

Accordingly this invention provides a vacuum head for use in transportation of sheet material comprising a plurality of compartments having gas impermeable side walls of which at least one is common to two compartments and each compartment is provided with a conduit communicating with means to vary the pressure in the compartment and a face having apertures for contacting the surface of the sheet material.

According to a further embodiment of this invention there is provided a pasty making machine comprising means for producing a continuous sheet of material, and a station at which portions cut from the sheet material are further processed, said portions being cut and transferred to said station by means of a head described above and modified by the provision of cutting means and a source of suction whereby the head cuts a portion from the sheet material, lifts the cut portion and transfers it to a further processing station, thereafter repeating the cycle of operations.

The sheet material may be pastry in which case the means for producing the sheet material may comprise a conventional 'sheeter' such as a three roll sheeter with variable speed control drive. The latter has a hopper into which pastry dough is placed and produces a continuous sheet, for example on to a conveyor. When the sheet material is pastry the further processing station can comprise for example a pie or pastry forming apparatus, especially the latter. This can take the form of a suitable die or dies for forming the cut out portion of pastry into a suitable shape and a hopper containing filling operating in timed relationship with the die or dies.

The cutting head may conveniently comprise a plate having a raised cutting blade attached thereto in the correct shape for the desired cut out portion.

The plate may be provided with a number of holes on its under face, within the cutting area, connecting with an internal chamber which in turn is connected to a source of vacuum. Thus, once the cutting blade has severed the desired shape of sheet material from the sheet suction can be applied so that the cut out portion adheres to the under face of the cutting head. The cutting head may then be lifted and transferred to the further processing station where the cut out portion is released by discontinuing the vacuum. In order to aid clean and quick release compressed air may be employed to blow off the cut out portion after the vacuum has been discontinued. The compressed air may be ducted through the same holes through which the vacuum operates, or may have an independent set of holes and chambers.Each compartment is provided preferably with an independant supply of compressed air so that if there is severe depressurisation of one of the compartments due to air leaking through .3 tear or other large fissure in a part of a portion cf the sheet of pastry adhering to the face of the vacuum head sufficient pressurisation can be generated in the other compartments so as to ensure satisfactory release of the portion. The compressed air can be supplied in different ways. However preferably each compartment is connected to its own bottle of compressed air.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view in vertical section of the invention head incorporating cutting means.

Figure 2 is a plan view of the cutting head shown in Figure 1.

Figure 3 is a diagrammatic general view of an apparatus constructed in accordance with the invention.

In Figure 1 an aluminium block (1) is partially hollowed out to form a vacuum cavity (2) into which is fitted a diaphragm (3) having a number of holes (5). The aluminium block terminates in a cutting edge (6) defining an area the size and shape of which is determined by size and shape of the portion of pastry which is required to be cut from a layer of pastry sheeting and to be transported by the head to a processing station in the invention pasty making machine. Vacuum cavity (2) is connected by a conduit (7) with a source of suction and positive air pressure. Vacuum cavity (8) is similarly connected by conduit (9) and the two cavities are separated by seal (10).

In Figure 1 the head is shown as just having cut a portion of pastry from a sheet of the material.

The vacuum is switched on and the portion of pastry (11) is held firmly against diaphragm (3). There is however a fissure (12) in the layer of pastry consequently air enters vacuum cavity (8) and the vacuum is reduced. Nevertheless because of the presence of seal (1() the vacuum in cavity (2, is maintained and the head is still able to carry the pastry layer to the next processing station.

Figure 2 illustrates a head having four separate compartments, for the purpose of making one pastry portion. The number of compartments required for each portion can vary depending on the area of portion to be made, its thickness and weight. In general each compartment should provide a lifting area corresponding to 25% to 33% of the area of the portion. Figure 2 illustrates the use of four compartments for the manufacture of a pastr/ portion measuring about 12 ins x 6 ins. For larger portions a head having a larger number of compartments may be desirable. The heads can also be designed to make a greater number of portions simultaneously thus increasing the output of the machine. Thus for portions having the above dimensions the head would be designed to have eight or twelve compartments depending on whether two or three portions are required to be made.

The compartments can be isolated completely from one another in which case air leaking into one compartment would not affect the intensity of the vacuum in the others. However in some vacuum systems it is sufficient to use an arrangement of ducts which permit some indirect passage of air from one compartment to another. It will be appreciated that a sheet of pastry could be so fissured that air leaks into all the compartments simultaneously resulting in failure of the head to perform satisfactorily. In these circumstances the machine operator should be in a position to observe the defective nature of the pastry sheet and to take suitable remedial action including if necessary to replace the pastry mix in the machine.

The physical properties of the pastry sheeting impose limitations on the size of holes to be used.

If they are too small they will become blocked by fragments of pastry. Alternatively if they are too large fragments of pastry can be sucked into the vacuum lines causing blockages. In either case the correct functioning of the head can be seriously impaired. For conventional short and puff pastry mixes holes having diameters in the range of 68-72 thousandth of an inch are preferred although larger or smaller holes can be used for other sheet materials having a degree of plasticity and cohesive strength differing from that of conventional short and puff pastry.

Figure 3 illustrates, in schematic form, an apparatus designated generally 13 for making pasties.

This comprises means for producing a sheet of pastry in the form of a standard three roll sheeter (14) having a dough hopper (15) and producing a continuous sheet of pastry (16). The latter is fed on to an endless conveyor (17). A cutting head (18), illustrated in Figures 1 and 2, cuts out portions from the sheet material (16) and transfers to the position (18a) shown chain dotted where it releases the cut out portion on to the dies (19) of a further processing station (20) adapted to produce pasties.

Station (20) comprises the dies (19) which have a scalloped configuration such that when they revolve as indicated by the arrows a pasty is produced having a scalloped seal. Pasty filling is provided from a hopper (21) operating in timed relationship with the revolving dies (19). Pasties so made are deposited on a conveyor (22) from which they may be taken for subsequent baking. The cutting head (18) is mounted both for vertical and translational movement by means of hydraulic or pneumatic pistons in the directions indicated by the arrows A and B.

The cutting head (18) is brought down on to the sheet of pastry (16) by means of the pneumatic or hydraulic cylinder where it cuts the portion of sheet material. At this point suction is applied through the holes (5), Figures 1 and 2, and the head (18) is lifted clear of the remainder of the sheet material taking the cut out portion with it.

The head is then moved transversely by the other of the hydraulic or pneumatic pistons until it reaches the position (18a) after which vacuum is shut off and compressed air applied to blow off the cut out portion on to the dies (19). The dies (19) are heated so that, after the cut out portion has received its measured amount of filling from the hopper (21), the dies (19) are rotated to form the pasty and the head of the dies causes the joined edge of the finished pasty to seal together. Conventionally the sealing of the joined edge of a pasty is carried out by wetting the pastry, but this is not practical for automatic operation since it is extremely difficult to control the correct amount of wetting and accumulations of sticky pastry quickly arise. It has been found that by heating the dies (19) a good seal is obtained in a reproduceable manner during continuous automatic operation. For this purpose it is desirable that the dies should be preheated before they make contact with the portions of pastry.

The apparatus of the invention can be used to provide simple and economical way of producing finished pasties, pies or the like ready for baking from raw pastry in an automatic manner. It can also be used for cutting and transporting portions of other sheet materials which cannot be handled by conventional vacuum heads.

Claims (9)

1. A vacuum head for use in the transportation of sheet material comprising a plurality of compartments having gas impermeable side walls of which at least one is common to two compartments and each compartment is provided with a conduit communicating with means to vary the pressure in the compartment and a face having appertures for contacting the surface of the sheet material.

2. A vacuum head according to Claim 1 provided with cutting means for forming a portion of sheet material from a continuous sheet.

3. A vacuum head according to either of Claims 1 or 2 wherein each compartment is connected to both a source of suction and a source of air pressure.

4. A vacuum head according to Claim 3 where in each compartment is connected to a separate source of compressed air.

5. A vacuum head according to any one of the preceding Claims wherein the area of the face of each compartment corresponds to 25% to 33% of the area of the portion of the sheet material to be transported.

6. A sheet handling apparatus comprising means for producing a continuous sheet of material a vacuum head according to any one of the preceding claims for cutting and transporting a portion of the material to a station in the apparatus where the cut portion is released by the head for further processing.

7. A sheet handling apparatus according to Claim 6 wherein the cut portion of sheet material is provided with a filling and opposing edges of the portion are sealed together with preheated dies.

8. A sheet handling apparatus according either Claims 6 or 7 wherein the sheet material is made of pastry.

9. Sheet handling apparati as hereinbefore described with particular reference to the drawings.

9. Vacuum heads as hereinbefore described with particular reference to the drawings.

10. Sheet handling apparatus as hereinbefore described with particular reference to the drawings.

New claims or amendments to claims filed on -Superseded claims 1-10 New or amended claims: CLAIMS

1. A vacuum head for use in the transportation of sheet material comprising a plurality of compartments having gas impermeable side walls of which at least one is common to two compartments and each compartment is provided with a conduit communicating with a source of vacuum and a source of air pressure and each compartment has an apertured face for contacting the surface of the sheet material.

2. A vacuum head according to Claim 1 wherein each compartment communicates with a separate source of air pressure.

3. A vacuum head according to either of Claims 1 or 2 provided with cutting means for forming a portion of sheet material from a continuous sheet.

4. A vacuum head according to any one of the preceding claims wherein the area of the face of each compartment corresponds to 25% to 33% of the area of the portion of the sheet material to be transported.

5. A sheet handling apparatus comprising means for producing a continuous sheet of material a vacuum head according to any one of the preceding claims for cutting the continuous sheet into portions and transporting the portions to a station in the apparatus where the cut portions are discharged from the head by compressed air for further processing.

6. A sheet handling apparatus according to Claim 5 wherein the cut portions of sheet material are provided with a filling and opposing edges of the portions are sealed together with preheated dies.

7. A sheet handling apparatus according to Claim 6 wherein the sheet material is made of pastry.

8. Vacuum heads as hereinbefore described with particular reference to the drawings.