Patent Application
20150013274
This application relates to and claims the benefit and priority to Spanish Patent Application No. 201331069, filed Jul. 12, 2013.
The present invention relates to product wrapping machines.
Product wrapping machines are known. Some wrapping machines comprise a plurality of transverse counter-jaws that are homogenously distributed in a forward movement direction of the products to be wrapped and are separated from one another by a specific separation distance, and two parallel supports between every two counter-jaws on which a product to be wrapped is supported arranged.
The machine comprises transport means for causing the counter-jaws to move in the forward movement direction, the counter-jaws and the supports being attached to said transport means. Therefore, as the transport means is moved in the forward movement direction, the counter-jaws, the supports and the products arranged on the supports are also moved in the forward movement direction. The transport means is in continuous movement.
The machine further comprises a lower unwinder where a first reel of film is arranged, an upper unwinder where a second reel of film is arranged, and an actuator which is suitable for acting on the supports, causing the film from the first reel to be unwound and arranged on the counter-jaws and the supports, and causing the film from the second reel to be unwound and arranged on the product to be wrapped. The products are arranged on the corresponding supports once the film from the first reel has been arranged on said supports and before the products are covered by the film from the second reel. This operation can be done manually or automatically.
The machine also comprises a transverse jaw which is suitable for being moved from an open position to a closed position in a closing direction perpendicular to the forward movement direction for sealing the films to one another and cutting them. In the open position, the jaw is separated from the counter-jaw, whereas in the closed position the jaw acts against the counter-jaw. Since the transport means is in continuous movement and minimum time is needed for the jaw to act against the counter-jaw in order to correctly seal and cut the films, the jaw is moved in the forward movement direction following the counter-jaw to return to its initial position once sealing and cutting have been correctly performed. This movement is cyclically repeated. Some machines comprise two jaws that are distributed in the forward movement direction and separated from one another by the same separation distance between every two counter-jaws, such that the two counter-jaws act simultaneously against two contiguous counter-jaws, machine productivity being increased by performing two operations simultaneously.
Due to the sealing process performed by the jaws, the wrapping in which a product is wrapped often adheres to the counter-jaws, and this can involve the wrapping tearing when causing the separation or peeling off thereof, can prevent product transport and can cause the formation of creases or poor finishes in a subsequent shrink wrapping process, for example, which can entail having to dispose of the wrapped product at hand, increasing costs associated with film consumption and disposed product reprocessing.
According to some implementations a product wrapping machine is provided that comprises a plurality of transverse counter-jaws that are homogenously distributed in a forward movement direction and are separated from one another by a specific separation distance suitable for housing a product, a lower unwinder for a first reel of film, an upper unwinder for a second reel of film, an actuator which is suitable for acting on the upper and lower supports, causing the film from the first reel to be unwound and arranged on the counter-jaws and the supports and the film from the second reel to be unwound and arranged on the products to be wrapped, and a plurality of transverse jaws that are homogenously distributed in the forward movement direction separated from one another by a separation distance equal to the separation distance existing between the counter-jaws. The jaws are suitable for moving in a closing direction perpendicular to the forward movement direction, from an open position to a closed position, against the counter-jaws for sealing the films to one another and cutting them. Two films are thus sealed to one another and the films are cut in an intermediate area, thus separating two adjacent products.
The machine further comprises a positioning device which moves all the jaws integrally in the forward movement direction and a jaw actuator for each jaw which causes the corresponding jaw to move in the closing direction, such that the jaws are suitable for moving simultaneously in the forward movement direction and for moving independently from one another in the closing direction.
The machine further comprises a tensioner or rocker arm suitable for collecting part of the film wrapping the product when a jaw leaves the closed position. When a jaw acts against its corresponding counter-jaw, the jaw is responsible for sealing a second end of the wrapping of a previously wrapped product and a first end of the wrapping of a product that is being wrapped, cutting the films in an intermediate area of the sealing area for separating both products from one another.
The tensioner is suitable for causing the film wrapping the corresponding product to be collected when the jaw is separated from the corresponding counter-jaw, such that it is separated or disengaged from the counter-jaw in the second sealing area. As a result, the risk of the film adhering to the corresponding counter-jaw due to the sealing processes, which can result in the wrapping tearing when the wrapped product has to leave the machine, is reduced. All this provides advantages with respect to the solution of the state of the art where jaws are moved simultaneously in the closing direction, such as, for example, the advantage of providing wrapped products with a smaller amount of film (which entails savings) and an improved outer appearance, and the film is separated from a counter-jaw, preventing it from adhering to same.
The operating method is also suitable for elongated product wrapping machines.
The operating method is designed for being implemented in a product wrapping machine such as the one mentioned above. The method comprises a sealing and cutting step in which the jaws are moved in the closing direction from an open position to a closed position against the counter-jaws for sealing the films to one another and cutting them, and in which the jaws then return to their open position once the sealing and cutting are performed, said sealing and cutting step being cyclically repeated.
The sealing and cutting step is performed independently for each jaw, the jaws being moved independently from one another to change from the open position to the closed position and vice versa. The method further comprises a collecting step after each sealing and cutting step of a jaw and before the following sealing and cutting step of the following jaw starts, in which part of the film wrapping a product the wrapping of which has been sealed at one end by the jaw which has previously performed a sealing and cutting step, is collected. One end of the wrapping is thus detached from its respective counter-jaw and savings in film are obtained by recovering part of the wrapping film of each product.
These and other advantages and features will become evident in view of the drawings and the detailed description.
a-2e show the perspective view of a detail of the machine of
a-3j schematically show the action of the jaws of the machine of
A first aspect relates to a product wrapping machine 100 such as that shown by way of example in
The machine 100 comprises transport means for causing the counter-jaws 1 to move in the forward movement direction X at a substantially constant forward movement speed, the counter-jaws 1 and the supports 2 being attached at the ends thereof to said transport means. Speeds other than a substantially constant forward movement speed are also contemplated. As the transport means moves in the forward movement direction X, the counter-jaws 1, the supports 2 and the products P arranged on the supports 2 are also moved in the forward movement direction X. The transport means may be a chain, belt or equivalent element on each side of the counter-jaws 1 (or supports 2) which causes the counter-jaws 1 (and supports 2) to move in a manner similar to a conveyor belt, so they comprise a plurality of guides guiding their movement. Hereinafter, when discussing the movement of the transport means, said movement must be interpreted as the movement of the area of the transport means where the products P to be wrapped and the already wrapped products P will move.
The machine 100 further comprises a lower unwinder 4 where a first reel 41 of film is arranged, an upper unwinder 5 where a second reel 51 of film is arranged, an actuator 8 for acting on each unwinder 4 and 5, causing the film from the first reel 41 to be unwound and arranged on the counter-jaws 1 and the supports 2, and the film from the second reel 51 to be unwound and arranged on the product P to be wrapped as said product P moves forward. The products P are arranged on the corresponding supports 2 once the film from the first reel 41 has been arranged on said supports and before the products are covered by the film from the second reel 51. This operation can be done manually or automatically. To facilitate the correct arrangement of the products P, the upper unwinder 5 may be arranged in the position furthest ahead in the forward movement direction with respect to the lower unwinder 41, thus enabling a loading area for the products P.
The machine 100 also comprises a plurality of transverse jaws 6, such as, for example three in number, that are homogenously distributed in the forward movement direction X with a separation distance D between them that is equal to the separation distance existing between the counter-jaws 1. The jaws 6 are designed for sealing and cutting the films wrapping the products P by means of acting against the counter-jaws 1 (each jaw 6 acting against a counter-jaw 1). Therefore, the jaws 6 can be arranged in an open position P1 where they do not act against the counter-jaws 1, and in a closed position P2 where they act against the counter-jaws 1. To change from the open position P1 to the closed position P2 or vice versa, the jaws 6 are moved in a closing direction Y perpendicular to the forward movement direction X. The jaw 6 is suitable for sealing two films to one another and for cutting the sealed films in an intermediate area of the seal. As shown in the sequence of
Since the counter-jaws 1 and the products P may move continuously due to the action of the transport means and since minimum time is needed for a jaw 6 to act against its corresponding counter-jaw 1 for a correct sealing and cutting operation, the jaws 6 are moved in the forward movement direction X following the counter-jaws 1 and the products P to then return to their initial position once the corresponding sealing and cutting of said products P are performed. These steps are performed cyclically. The machine 100 comprises a positioning device 10 to provide movement of the jaws 6 in the forward movement direction X (and the return thereof).
Based on the foregoing it can be seen that when there is more than one jaw 6, a product P is wrapped by the action of two adjacent jaws 6: one jaw 6 forms the seal or closure of one side of the wrapper wrapping the product P, i.e., first closure, whereas the other jaw 6 forms the seal or closure of the other side of the wrapper wrapping said product P, i.e., second closure. For example, the jaw 6 furthest ahead in the forward movement direction X forms the first closure, sealing the films to one another and cutting them on one side of the product P, and the contiguous jaw 6 forms the second closure, sealing the films to one another and cutting them on the other side of the product P. On the other hand, each jaw 6 intervenes in the wrapper of two contiguous products P: when one jaw 6 forms the first closure for the wrapper of a product P, the same action causes the second closure for the wrapper of a preceding product to be formed. In other words, the action of one jaw forming the second closure in the wrapper of a product P entails forming the first closure in the wrapper of the product P that is going to be wrapped next in addition to cutting the films, causing said products P to separate from one another.
The machine 100 further comprises a jaw actuator 9 for each jaw 6 causing the corresponding jaw 6 to move in the closing direction Y. Therefore, with the machine 100 the jaws 6 are suitable for moving simultaneously in the forward movement direction X as a result of the positioning device 10 and for moving independently from one another in the closing direction Y as a result of the different jaw actuators 9.
The machine further comprises a tensioner 7 or rocker arm suitable for collecting part of the film wrapping the product P when a jaw 6 leaves the closed position P2. When this occurs, the film is no longer locked between the jaws 6 and the counter-jaws 1, and as a result of the action of the tensioner 7, which always tries to keep the corresponding film slightly taut, the film arranged on the corresponding sealing area is collected and separated from said sealing area, preventing it from adhering to the corresponding counter-jaw 1.
The tensioner 7 is associated with the upper unwinder 5 and is suitable for acting on the film from the second reel 51 which is arranged in said upper unwinder 5, such that when said film is collected, it does so by returning the film to the second reel 51. When no jaw 6 is in the closed position 6, the films wrapping the last product P on which the jaw 6 has acted are only sealed at the end furthest ahead in the forward movement direction. Said end has been closed as a result of the seal joining the films of the reels 41 and 51, whereas the other end reaches reel 51 (over the product P) on one hand and reel 41 (under the product P) on the other hand. The tensioner 7 collects the film partially wrapping said product by the end reaching the reel 51.
In addition to the mentioned advantage relating to the separation of the already sealed film from the counter-jaws 1, the machine 100 uses a smaller amount of film when wrapping a product P, which entails a considerable production cost reduction. This does not occur in the state of the art, not even by using a tensioner such as that of the machine 100 since if there is a plurality of jaws acting simultaneously against corresponding counter-jaws, the films are cut without there being any chance to collect part of the film, there being no possibility of film savings in all the wrapped products unlike what occurs in the machine 100. Since the jaws 6 can be actuated independently from one another as a result of the jaw actuators 9, the machine 100 enables the jaws 6 to act on corresponding counter-jaws 1 one at a time, such that every time a jaw 6 stops acting against its corresponding counter-jaw 1, film collection can carried out before causing the following jaw 6 to act against its corresponding counter-jaw 1. Therefore, the advantage of film savings is obtained while at the same time productivity increases as a result of using a plurality of jaws 6. The film savings can exceed 30% compared to the wrapping film used for the same product P in a machine of the state of the art.
The machine 100 further comprises control means, not depicted in the drawings, which are responsible for controlling the movement of the jaws 6. The control means is responsible for causing the positioning device 10 and the jaw actuators 9 to be actuated and the jaws 6 to move sequentially against the corresponding counter-jaws 6 to obtain the aforementioned advantages. The control means corresponds with a controller, processor or another device capable of performing that task.
When the films are sealed, if they are heat-sealed they may adhere to the counter-jaw 1 on which sealing is performed, and as mentioned before, as a result of the jaws 6 being able to move individually in a sequential manner, and as a result of the tensioner 7, one end of the wrapping of the product P is separated from the counter-jaws 1 (one end of the wrapping of the product P which is arranged lagging further behind the corresponding counter-jaw 6 in the forward movement direction X) and wrapping film consumption is reduced.
To separate or peel off the other end of the wrapping, the machine 100 comprises separating means acting on the film wrapping a product P once the product P is already wrapped. The separating means cause the distance between a wrapped product P and the counter-jaws 1 between which it is arranged to increase. In the embodiment shown in the drawings, the separating means do this by causing the transport means to become misaligned at a point where the products P are already individually wrapped, i.e., at a point after where the jaws 6 act against the counter-jaws 1, where the films forming the wrapping are still hot and can more readily peel off (the adhesion problem intensifies once said films have cooled, which makes peeling them off the counter-jaws 1 without damaging the wrapping difficult or impossible). In another embodiment, this could be done by means of an upward thrust on the product P which would separate it from the support 2 and therefore the counter-jaws 1, by means of an actuator specific for such purpose (the actuation thereof would be controlled with control means). Therefore, the part of the wrapping of the product P which may be on at least one of the counter-jaws 1 would be separated.
In the embodiment of the machine 100 shown in the drawings, the separating means comprise at least three rollers 91, 92 and 93 distributed in the forward movement direction X, and the machine 100 comprises two parallel separating means between which the counter-jaws 1 are located. The first roller 91 and the last roller 93 are aligned with one another. The intermediate roller 92 is responsible for misaligning the transport means and is arranged such that it is misaligned with respect to the other two rollers 91 and 93. In said embodiment, the intermediate roller 92 is arranged at a height less than the height at which the other two rollers 91 and 93 are arranged, and the transport means passes under the first roller 91 and the last roller 93 and over the intermediate roller 92.
The intermediate roller 92 is sized such that two contiguous counter-jaws 1 are inclined in opposite directions when they are located on said intermediate roller 92, following a curved path with respect to an axis of rotation of the intermediate roller 92, whereas the product P arranged between said counter-jaws 1 is kept centered on the support 2. In that situation, since the product P is kept in place, the end of the wrapping of the product P that may be adhered to a counter-jaw 1 is separated from or peeled off said counter-jaw 1, because the distance between a product P and the counter-jaws 1 between which it is arranged increases, and therefore the part of the wrapping of the product P that may be on a counter-jaw 1 is detached from it. The effect of the separating means is schematically depicted in
The machine 100 further comprises a shrink wrapping oven 200 where the already wrapped products P are introduced after passing through the separating means so that the film wrapping the products is shrink-wrapped and fitted thereon. The oven 200 may not be part of the machine 100.
A second aspect relates to an operating method for being implemented in a wrapping machine such as that discussed above. According to one implementation the operating method comprises a sealing and cutting step in which the jaws 6 are moved in the closing direction Y from their open position P1 to their closed position P2 against the counter-jaws 1 for sealing the films to one another and cutting them, and in which the jaws 6 then return to their open position P1 once sealing and cutting are performed, said sealing and cutting step being cyclically repeated. The sealing and cutting step is performed independently for each jaw 6, the jaws 6 being moved independently from one another to change from the open position P1 to the closed position P2 and vice versa. The method further comprises a collecting step after each sealing and cutting step of a jaw 6 and before the following sealing and cutting step of the following jaw 6 starts, in which part of the film wrapping a product P the wrapping of which has been sealed at one end by the jaw 6 that has previously performed a sealing and cutting step is collected. The advantages discussed above when explaining the first aspect can thus be obtained.
The jaws 6 are moved from the open position P1 to the closed position P2 in a sequential manner, as shown in
Therefore, before one jaw 6 acts against its corresponding counter-jaw 1, since no other jaw 6 is acting against a counter-jaw 1, the film can be slightly taut in the direction of the reel 51 as a result of the tensioner 7 of the machine 100, part of said film being collected, such that one end of the wrapping of the product P is separated from its corresponding counter-jaw 1 and the amount of film existing between said jaw 6 and the preceding jaw 6 is reduced, which means there is less film for wrapping the product P arranged between the counter-jaw 1 corresponding to said jaw 6 and the counter-jaw 1 corresponding to the preceding jaw 6. Furthermore, possible creases in the film that would negatively affect the outer appearance of a wrapped product P are reduced or eliminated since the film is slightly taut.
The movement sequence of the jaws 6 is continuous, one jaw 6 performing the sealing and cutting step when its adjacent jaw 6 in the forward movement direction X has concluded the sealing and cutting step and after the collecting step, except when the sealing and cutting step of the jaw 6 arranged in the position lagging furthest behind in the forward movement direction X is performed, in which case, after the corresponding collecting step, the following sealing and cutting step is performed by the jaw 6 arranged in the position furthest ahead in the forward movement direction X, once it has returned to its initial position.
The process is explained below in reference to
a shows all the jaws 6 in the open position P1 and in their position lagging furthest behind in the forward movement direction X which corresponds with the initial position.
b shows the actuation of the first jaw 6 with respect to its corresponding counter-jaw 1 in its closed position P2, whereas the other jaws 6 remain in the open position P1. The jaw 6 seals one end of the product P referenced in
c shows the same situation as
d shows that the first jaw 6 has returned to an open position P1 while the other jaws 6 remain in the open position P1.
e-3g show the same development but in reference to the second jaw 6, and
The method further comprises a separating step which causes the distance between a wrapped product P and the counter-jaws 1 between which it is arranged to increase, such that the part of the wrapping of the product P arranged on a counter-jaw 1 is detached from said counter-jaw 1. In one embodiment of the method, the distance between a wrapped product P and the counter-jaws 1 between which it is arranged is increased by separating the counter-jaws 1 from one another, and said separation is done by causing the counter-jaws 1 to rotate in opposite directions. This process and the advantages it entails have been discussed above in the explanation referring to the first aspect, in relation to the separating means, which are responsible for performing the separating step.
In another embodiment of the method, the distance between a wrapped product P and the counter-jaws 1 between which it is arranged is increased by causing an upward thrust on the product P, the product P thus being separated. The product P thus moves away from the counter-jaws 1, and the part of the wrapper that may adhere to one of the counter-jaws 1 is detached from same.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201331069 | Jul 2013 | ES | national |
