Machine for canning foodstuff product, such as tuna fish and similar

Abstract

A canning machine for a foodstuff product (2), such as tuna fish and similar, comprises a conveyor belt (1) suitable for carrying the foodstuff product (2) in a compressing and shaping device comprising a knife (11) suitable for cutting substantially parallelepipedal portions (12) of the foodstuff product (2) and a compression channel (7) closed at one end by means of a shaping member (8) and at the other end by means of a compactor (9) slidable in the compression channel (7). Two openings (14) are made in the bottom wall of the compression channel (7) in order to allow the passage of a pair of dies (16) and of a pair of ejecting pistons (15) which in their initial position close said openings (14) without substantially protruding into the compression channel (7). Said ejecting pistons (15) are capable of a cyclic movement comprising a backward movement with respect to the compressing and shaping device, a forward movement through said openings (14) and a movement of return to the initial position.

Description

[0001] The present invention relates to an improved canning machine, and particularly it relates to a machine suitable for shearing, shaping and canning a foodstuff product such as tuna fish and similar.

[0002] It is known that canning of tuna fish presents a number of problems due to the intrinsical nature of this foodstuff and above all to the irregular consistency thereof, which makes it necessary to compress it in order to bring it to a predetermined density and therefore to maintain within acceptable limits the weight of the product introduced into each can.

[0003] Machines for cutting, compressing and canning tuna fish are already known. For example, patent U.S. Pat. No. 5,203,141 in the name of the same applicant describes a machine wherein the portions of tuna fish obtained by cutting the product are pushed into a compression channel which is closed at one end by means of a shaping member provided with two semi-cylindrical concavities. The portions of tuna fish which are subsequently compacted against said shaping members are sheared by means of two dies, thus forming pairs of cylindrical cakes. These are transferred inside cans or tins by means of ejecting pistons which enter the compression channel by passing through suitable openings provided in the bottom wall of said channel. In their rest position, said ejecting pistons are already partially inserted into said openings and close them, thus avoiding that the foodstuff product comes out of the channel itself while it is subjected to the compressing and shaping steps.

[0004] However, a problem of said known machine consists in that the tuna fish cakes which can be obtained by using it are characterized by a poor surface quality. As a matter of fact, the pressure exerted on the tuna fish portion during the shaping step of the cakes causes the foodstuff to stick to the walls of the compression channel, and particularly to the surface of the ejecting pistons. At the moment of detaching the cakes from the pistons, some fibers of the foodstuff product stick to the pistons themselves. As a result, the surfaces of the so obtained cakes are imperfect; further, the ejecting pistons are encrusted and cannot be cleaned unless the machine is stopped.

[0005] Object of the present invention is therefore to provide a machine which is free from the following drawbacks. Said object is obtained by a machine whose main features are specified in the first claim and other features are specified in the following claims.

[0006] An advantage of the canning machine according to the present invention consists in that it allows to prevent the sticking of the cakes to the ejecting pistons and therefore to improve the surface quality of the cakes. As a matter of fact, the ejecting pistons thereof are capable of a cyclic movement comprising a backward movement with respect to the compression channel in the moment when the excessive pressure exerted on the tuna fish cakes would cause the above mentioned undesired sticking.

[0007] Further advantages and features of the machine according to the present invention will appear to those which are skilled in the art from the following detailed description of one embodiment thereof with reference to the only FIG. 1, which shows a perspective simplified view of the central nucleus of the machine according to said embodiment of the invention.

[0008] With reference to said FIG. 1, there is shown that the machine according to the present embodiment of the invention comprises in a known way a conveyor belt 1, suitable for carrying a foodstuff product 2, for example tuna fish, through an opening 3 of a compressing and shaping device, wherein the foodstuff product is brought to the density required. Said compressing and shaping device comprises a front block 4, a back block 5 and two side members 6 which connect said front and back blocks and form the side walls of a compression channel 7 positioned in the middle of said device. The compression channel 7 is closed at one end thereof by means of a shaping element 8 and at the other end by a compactor 9, which slides in the compression channel 7 under the thrust of a pneumatic piston 10.

[0009] Once crossed opening 3, the foodstuff product 2 is cut by means of a knife 11 which provides a portion 12 of tuna fish, which is inserted into the compression channel 7 in order to be brought to the desired density. Knife 11 shown in the figure is of the type with two opposed blades, but it can be of any other type suitable for this purpose.

[0010] Tuna fish portion 12, which has a substantially parallelepipedal shape, is pressed by compactor 9 against shaping element 8. Said shaping member 8 has a substantially flat bottom, with a separating wedge 13 at the center thereof, suitable for dividing portion 12 of tuna fish substantially in two parts. Separating wedge 13 is advantageously provided with an enlarged base through which it is connected to shaping member 8, and has side profiles which are suitably arched as quarters of a circle. On the bottom of the compression channel, at the sides of separating wedge 13, two openings 14 having circular shape are provided. During the compressing step, said openings 14 are closed by means of ejecting pistons 15, which are inserted inside said opening without protruding inside channel 7. In the rest of the description and in the claims, with “initial position” of the pistons will be meant the position which was just described, occupied by the pistons during the compression step. The pressure exerted onto the tuna fish portion 12 during the compression step is generally not high enough so as to cause the undesired sticking of the foodstuff product to the ejecting pistons 15.

[0011] Said portion 12 is then subjected to a shearing step carried out by two dies 16, provided with cutting edges arched as quarters of a circle and positioned behind the back block 5 of the compressing and shaping device. Thus, two semi-finished tuna fish cakes are separated, which are made cylindrical in a subsequent shaping step carried out by means of side shaping members 17 slidably arranged inside the two wings of a channel 18 which perpendicularly intersects compression channel 7. The ends of said side shaping members 17 which are turned towards compression channel 7 are provided with concavities having a substantially semi-cylindrical shape. The two wings of channel 18 are suitably obtained inside the side members 6 of the compressing and shaping device.

[0012] According to the invention, at the same time of the shaping step, the ejecting pistons 15 come out of openings 14 and move backwards with respect to the compressing and shaping device, away from it. Said backward movement of the ejecting pistons has the purpose of lightening the pressure of the foodstuff product on their surfaces so as to prevent the undesired sticking.

[0013] Once the above mentioned compressing, shearing and shaping steps are completed, the tuna fish cakes are ejected from the compressing and shaping device by means of the ejecting pistons 15 which approach again the compressing and shaping device, penetrate into the compression channel through openings 14 and push the tuna fish cakes into two cans 18, which are arranged at two openings 19 made in the front block 4. A sliding shutter 20, which has the purpose of preventing the foodstuff product from coming out of channel 7 during the compressing and shaping steps, is raised in order to allow the ejection of the cakes.

[0014] Therefore, the cyclic movement of ejecting pistons 15 comprises first a backward movement starting from said initial position, then a clear forward movement so as to pass through openings 14 and then a return to the initial position. Said cyclic movement can be controlled by a cam (not shown in the figure) which is driven, for example, by the movement of the side shaping members 17.

[0015] Further advantages and features can be made by those which are skilled in the art to the herewith described and illustrated embodiment by remaining within the scope of the invention.

Claims

1. A canning machine for a foodstuff product (2), such as tuna fish and similar, comprising a conveyor belt (1) suitable for carrying the foodstuff product (2) in a compressing and shaping device comprising a knife (11) suitable for cutting substantially parallelepipedal portions (12) of the foodstuff product (2) and a compression channel (7) closed at one end by means of a shaping member (8) and at the other end by means of a compactor (9) slidable in the compression channel (7), two openings (14) being made in the bottom wall of the compression channel (7) in order to allow the passage of a pair of dies (16) and of a pair of ejecting pistons (15) which in their initial position close said openings (14) without substantially protruding into the compression channel (7), characterized in that said ejecting pistons (15) have a cyclic movement comprising a backward movement with respect to the compressing and shaping device, a forward movement through said openings (14) and a movement of return to the initial position.

2. A machine according to claim 1, characterized in that said compressing and shaping device also comprises a pair of side shaping members (17), slidably arranged inside the two wings of a sliding channel (18) which perpendicularly intersects compression channel (7), each side shaping member (17) having one end provided with a semi-cylindrical concavity suitable for penetrating into the compression channel (7) by sliding between one die (16) and the bottom of the shaping member (8), the outlet of the two wings of the sliding channel (18) onto the compression channel (7) being provided with shutters which can be opened.

3. A machine according to the preceding claim, characterized in that the backward movement of the ejecting pistons (15) occurs at the same time of the penetration of the side shaping members (17) into the compression channel (7).