GB2224712A - Apparatus for wrapping articles in shrink-film - Google Patents

Abstract

An apparatus 1 for wrapping articles 54 in shrink film 56 is attached to the receiving end of a shrinking apparatus and has, in line, an article roller support 21 for manually starting the wrapping operation with the shrink film delivered from a film outlet 22 in the support face and a wrapped article conveyor 24 for drivingly delivering the wrapped article to a conveyor 6 passing through a heat shrink tunnel 8. Downstream of the film outlet 22 is provided a film cutting device 23 operated via a light barrier sensor (35) by a same control device (34) as the wrapped article conveyor (24). Therefore, the wrapping of the article (54) can be initiated manually ensuring a proper setting of the shrinking film and then the remaining part of the wrapping, film separating and shrinking operation will be performed completely automatically allowing to meanwhile begin manually with a next wrapping cycle. <IMAGE>

Description

Apparatus for wrapping articles in shrinking film This invention relates to wrapping apparatuses for wrapping articles in shrinking film or similar wrapping means, whereby after wrapping the wrapped article is positioned or transported through a shrinking station for heating the shrinking film wrapped around the article to such an extent that it shrinks closely against the article. By this way the shrinked film or foil is attached to the article in such a manner that it can only be detached by destroying.

In such apparatuses sofar it has been relatively troublesome to wrap into the shrinking film and to quickly bring the so wrapped article into the shrinking station.

It is an object of the invention to provide a wrapping apparatus for easily wrapping articles in shrinking film. Another object of the invention is to provide a wrapping apparatus capable to directly deliver the wrapped article into the shrinking station. Another object of the invention is to provide a wrapping apparatus, wherein the shrinking film can be easily deliver ed to the article to be wrapped without this shrinking film disturbing processing. Still another object of the invention is to provide a wrapping apparatus capable to adapt the size of the shrinking film to the article to be wrapped. A further object of the invention is to provide a wrapping apparatus capable to prefix the shrinking film to the wrapped article before shrinking.

According to the invention an apparatus for wrapping articles in shrinking film provides a wrapping support constructed for supporting each article in a manner that this article can be moved in an advance direction during and after wrapping, a film delivering means being provided in the vicinity of this wrapping support for simultaneously wrapping the delivered shrinking film around the article during at least partial support of the article on the wrapping support. Furthermore, the apparatus advantageously has a film cutting device to separate a piece of shrinking film from a film source, said film piece having a size adapted to the size of the article to be wrapped. It is preferred to also have a conveyor associated to the wrapping station for transporting each wrapped unit directly after wrapping into the shrinking station.

The wrapping support or the conveyor need not to be motorized for drivingly advance or convey the article before or after wrapping. To provide an apparatus very easy to handle the support is not motorized but the conveyor is so that the user can determine the speed of wrapping but after wrapping the conveyor will auto matically take over and directly transport the wrapped unit into the shrinking station.Nevertheless, means are provided for a substantial slideless but advanceably guided support of the article in the wrapping station which means can be a number of support rollers freely turnable at least in a direction of rotation corresponding to the advance direction, For avoiding backward movement of the article opposite to the advance direction in the wrapping station means are provided for substantially blocking such backward movement, for example by frictional breaking forces excerted on the article by means of the support face.

For example at least one of the support rollers is mounted in the manner of a free wheel roller capable only to rotate in one direction and being blocked against rotation in the opposite direction.

For preventing the delivering end of the shrinking film to withdraw out of the handling area of the wrapping support means are provided for blocking this shrinking film against withdrawal. These blocking means preferably are located substantially upstream of the film outlet issuing in the vicinity of the wrapping support or in the support surface respective support plane itself. This blocking means as well can have a free-wheel roller guiding the film delivered from the film source over a part of the roller circumference.

To provide a still easier handling during or after wrapping the article by kind of semi-automatic control of the apparatus means are provided to drivingly engage the article when it has manually moved to a distinct point of the wrapping support or conveyor. These means can have a control device for initiating the operation of the conveyor or a motor driving the conveyor.

Another means are provided for automatically or semiautomatically seperating the piece of shrinking film in use for wrapping from a film strand. These means preferably are constructed for seperating this piece of shrinking film after it has at least partly been wrapped around the article so that the end of this piece which is last folded against the article during wrapping will be positionally secured by the film strand until wrapping is completed.

A sensor for detecting a position of the article to be wrapped respective the wrapped article is preferably a common sensor for both control means described above.

For example, this sensor is a light barrier sensor.

Means for securing the wrapped film with respect to the article until shrinking has taken place may be simply provided by positioning the end of the film piece last enveloped against the article in such a way that it projects counter to the advance respective conveying direction and that it is substantially located between the bottom face of the article and the supporting or conveying surface, thereby frictionally securing the wrapped shrinking film by the weight of the article.

For easy adjusting and supporting of the wrapping apparatus without an extra base construction being needed according to the invention the wrapping apparatus is constructed to be mounted on the shrinking station in a freely projecting manner.

In any case, an advantageous conveying connection between the wrapping apparatus and the shrinking station will be provided when the delivering end of the conveyor for the wrapped unit is connected to a receiving end of a shrinking conveyor passing through the shrinking zone of the shrinking station. Usually this shrinking zone is a shrinking tunnel having an inlet end for the wrapped unit and an outlet end for the wrapped unit enveloped in the shrinked film.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which - figure 1 is a side elevation of the wrapping apparatus attached to the receiving end of a shrinking apparatus, - figure 2 is an enlarged side elevation of the wrapping apparatus according to figure 1 during beginning of the wrapping operation and - figure 3 is the side elevation according to figure 2 in a condition after almost finishing the wrapping operation.

Referring first to figure 1 the entire wrapping and shrinking machine shown therein comprises an apparatus 1 for wrapping successively one article 54 after another into an end section of a shrinking film and a shrinking apparatus 2 for converting said film section immediately after wrapping into a shrinked film 61 at least partly and tensioned enclosing the article 54.

From the beginning of the wrapping operation to the end of the shrinking process the article 54 will be moved in a straight advance direction according to arrow 25 and substantially horizontal.

The wrapping apparatus 1 is mounted in a freeling pro Ejecting manner to a base construction 3 of the shrinking apparatus 2 having a base chassis 4 provided with base feet vertically adjustably mounted for adjusting a shrinking path, for example in a substantially horizontal plane. The base chassis 4 is bearing a shrinking conveyor 6 constructed as a belt conveyor and driven by a conveyor motor 7 mounted at the end of the base chassis 4 remote from the wrapping apparatus 1.

An uppermost section of the conveyor belt determines the shrinking path and passes through a shrinking tunnel 9 providing a shrinking station 8. An upper hood providing the shrinking tunnel 9 provides lateral shrinking heaters 10 and is vertically adjustable with respect to the base chassis 4 by means of a motorized tunnel lift 11 to accomodate to different sized articles 54 to be enveloped in shrinking film. The shrinking tunnel 9 provides a receiving opening and a delivering opening for the articles 54, the receiving opening being located downstream of a receiving end 13 of the shrinking path 12 and the delivering opening being located upstream of a delivering end 14 of the same, this delivering end 14 projecting in advance direction arrow 25 over the base chassis 4.

Referring now to figures 1 to 3 it can be seen that the wrapping apparatus 1 is solely mounted to an upstream front frame 15 of the base chassis 4 by at least one mounting support 16 detachably fixed to the base chassis 4 in such a manner that any convenient shrinking apparatus 2 may be equipped with the wrapping apapparatus 1 according to the invention, The mounting support 16 is part of a base frame 17 of the wrapping apparatus 1, this base frame 17 having two opposite and parallel lateral frame arms 18 freely projecting in an upstream respective counter-direction to the advanced direction arrow 25. The lateral outside faces of the lateral frame arms 18 are positioned substantially in line with the lateral outside faces of the base chassis 4 and are rigidly connected by a number of cross bars 19.

The upstream end of the wrapping apparatus 1 provides a wrapping station for at least partly manually wrapping the article 54 in a film section and, thereby, supporting the article 54 on a wrapping support 21. At a distance from its upstream end the wrapping support 21 is penetrated by a film outlet 22 adapted to make the shrinking film respective the film section available in a plane substantially perpendicular to the advance direction arrow 25, this distance being greater than the extension of each article 54 to be wrapped in the advance direction arrow 25.The length extension of the slot-like film outlet is greater than the associated width extension of the articles 54 perpendicular to the advance direction arrow 25 so that the shrinking film will be available in the vicinity of the film outlet 22 by such a width that this shrinking film will laterally project over both sides of the wrapped article 55.

Downstream of the film outlet 22 there is provided a film separating respective cutting device 23 for oper ating in the vicinity of the support face of the wrapping support 21 and again substantially immediately adjacent to the film cutting device 23 in a downstream direction there is provided a wrapped article conveyor 24 having a length extension substantially the same as the wrapping support 21. This wrapped article conveyor 24 is mounted on the base fram 17 of the wrapping apparatus 1 and transportingly connects the wrapping support 21 to the receiving end 13 of the shrinking apparatus 2.

The support face of the wrapping support 21 is provided by a number of, for example, eleven relatively slim support rollers 27 mounted between brackets of a support frame 29 for free rotation in opposite directions.

The support fram 29 is vertically adjustably mounted on the base frame 17 by means of adjusting bolts 30 in such a way that the upstream and the downstream ends of the wrapping support 21 can be separately adjusted in height within limits, thereby providing a possibilty to adjust the wrapping support 21 with respect to its inclination in the advanced direction arrow 25. Each support roller 27 is formed by a single cross-shaft parallel to all other support rollers 27 and separated from the in each case adjacent support roller or support rollers 27 only by tiny gap, all support rollers 27 having same diameter, being located in a common axial plane and providing a substantially plane supporting face. Two adjacent ones of these support rollers 27 bound the film outlet 22 with their circumferences, thereby providing one of said gaps as a film outlet.

These outlet bounding support rollers 27 are the fourth and third last ones of the total number of the support rollers 27 when counted in the advance direction arrow 25.

The last two support rollers are of a slightly smaller length than the others and are bounding a slightly wider gap associated to the film cutting device 23 mounted on the support frame 29. The film cutting device 23 has a tensioned separating wire 33 located substantially parallel to the supporting face of the wrapping support 21 and perpendicular to the advance direction arrow 25, this separating wire 31 being substantially vertically movable through said associated gap from a position below to a position above the supporting face by means of a cutting lift 32. This cutting lift 32 provides two simultaneously operating operating cylinders 33 mounted on the underside of the support frame 29 between the lateral frame arms 18 and bearing the separating wire 31 on the upper ends of their upwardly projecting piston shafts via a fork-like cross bar.The separating wire 31 can be electrically circuited for being heated.

For automatically operating the film cutting device 23 and the wrapped article conveyor 24 a control device 34 is provided having an article sensor 35 in the form of a light barrier sensor 35 provided by a lateral light emitter on one side of the supporting face and a opposite lateral light receiver located on the other side of the support face, the light axis being located slightly above the support face, parallel thereto and perpendicular to the advance direction arrow 25. This sensor axis is provided slightly upstream of the film cutting device 23. When the sensor 35 is first activated by interrupting the light beam with the front end of the wrapped article 55 the wrapped article conveyor 24 starting to operate by energizing a conveyor motor 41.

Simultaneously the cutting lift 32 may be operated in such a way that the separating wire 31 retracts below the supporting and transport face although the separating wire 31 may already be in such a position by means of a suitable operation control. When after this first activation of the sensor 35 the light beam is given free again by the fact that the backward end of the wrapped article 55 has passed the sensor 35 provides a second activating condition thereby controlling the film cutting device 23 to operate in a separating cycle and to initiate a time delay device for stopping the wrapped article conveyor 24 only after a predetermined time sufficient to deliver the wrapped article 55 from the conveyor 24 to the shrinking conveyor 6. The separating wire 31 preferably is an electric resistant wire heated by electric currency and, therefore, separating the film section 58 wrapped around the article by means of melting.

The wrapped article conveyor 24 is, like the wrapping support 21, an integrated unit having a conveyor frame 36 vertically adjustable by adjusting bolts 37 in a manner similar as described by way of the support frame 29 so that the upstream and downstream ends of the wrapped article conveyor 24 may be independently adjusted within limits to adapt to the downstream end of the wrapping support 21 or the receiving end 13 of the shrinking conveyor 6. These two ends of the wrapped article conveyor 24 are provided by two end rollers 38, 39 guiding a number of laterally adjacent conveyor belts. The conveyor motor 41 is vertically adjustably mounted independent from the mounting support 16 directly on the front frame 15 of the base chassis 4 and drivingly connected to the downstream end roller 39 by means of a conveyor gear 42 provided as a belt gear.

The conveyor motor 41 is located below the base frame 17 with an upright motor axis driving the conveyor gear via an angle gear box.

The shrinking film 56 is endlessly delivered to the film outlet 24 from a film source 43 entirely located below the base frame 17 and, therefore, easily accessible for recharging. The shrinking film 56 is made available in the form of a storage roll 44 connectable with a central roll shaft 45 having end studs for rotational bearing on top of and between two adjacent horizontal bearing rollers 46 providing a roller couple.

One of these roller couples is mounted on the inside of the upwardly projecting arm end of each of two bearing arms 47 projecting counter to the advance direction arrow 25 from a mounting support 48 detachably mounted to the front frame 15 of the base chassis 4 in a similar manner as the mounting support 16. The bearing arms 47 are rigidly connected to each other by cross bars to provide an integrated unit and receive the horizontal storage roll 44 inbetween them.

The storage roll 44 is located in such a manner that the shrinking film 56 is issuing from a roll side facing counter to the advance direction arrow 25, the shrinking film 56 issuing in an upward and forwardly inclined delivering direction arrow 26 straight to a blocking device 49 for preventing movement of the shrinking film 56 counter to the delivering direction arrow 26. The blocking device 49 has a number of coaxially adjacent guide rollers 50 rotatably mounted on free ends of roller levers 51 projecting substantially in the advance direction arrow 25 from a common lever axis 52.The shrinking film 56 is led around the circumference of the guide rollers 50 on a side remote from the film issuing side of the storage roll 44 and substantially facing in advance direction arrow 25, the angle of the leading contact between the shrinking film 56 and the guide rollers 50 being substantially at least 90 , but less than 1800.

The guide rollers 50 are located below the support roller 27 downstream of and bounding the film outlet 22 and the rotation axis of the guide rollers 50 which is parallel to the axis of the support rollers 27 is positioned slightly upstream of the downstream outlet bounding support roller 27 somehow between the axis thereof and the gap providing the film outlet 22. The diameter of the guide rollers 50 is substantially greater than the one of the support rollers 27 and the guide rollers 50 are spring biased against the lower section of the support roller 27 located above them, thereby providing a transition gap for the shrinking film 56.From the guide rollers 50 the shrinking film 56 is led into the gap providing the film outlet 22 in an opposite direction of curvature around part of the circumference of the downstream film outlet bounding support roller 27 and dependent from the position of the film end 57 as well around part of the circumference of the upstream film outlet bounding support roller 27. The guide rollers 50 are constructed as freewheel rollers only capable to rotate in a direction corresponding to the delivering direction arrow 26 and blocking against rotation in the opposite direction, whereby the guide rollers 50 and the film outlet bounding support rollers 27 are only driven via the shrinking film 56 when the film end 57 is pulled out of the film outlet 22.For spring biasing the guiding and blocking device 49 coupling springs 53 are provided between downwardly projecting lever arms of the lever axis 52 and the piston shafts of the cutting lift 32, whereby the spring biasing of the guide rollers 50 is slightly increased during separating operation of the film cutting device 23 although instead or additionally thereto a cam control may be provided for the guiding and blocking device 49.

The operation of the embodiment described is as follows: An article 54 to be wrapped into a shrinking film which then has to be shrinked around the enveloped article is put on the upstream end of the wrapping support 21 having an initial free-wheel roller 28 only freely rotratable in a direction corresponding to the advance direction arrow 25, the upper face of this free-wheel roller 28 being located in the support plane although the diameter of this free-wheel roller 28 is substantially larger than the one of the support rollers 27. The film end 57 projecting above the film outlet 22 is then manually pulled towards and above the top side of the article 54 in a direction substantially counter to the advance direction arrow 25.During this step of processing the article 54 is either supported on the wrapping support 21 freely projecting with its backward end or this backward end is instead or additionally manually lifted slightly so that only the front lower edge of the article 54 is supportingly engaging the wrapping support 21. The film end 57 is pulled over the backward end face of the article 54 and at least part of the bottom face, thereby coming to engagement between this bottom face and the support face of the wrapping support 21. By these means as well as by means of the free-wheel roller 28 the film end 57 now underlapping the article 54 is securred to the article 54 by clamping friction between the bottom face thereof and the support face.

The so pre-wrapped article 55 is now manually advanced in direction arrow 25 towards the film outlet 22, thereby first driving over and past film outlet 22 with its front end and then first time activating the sensor 35 of the control device 34. During the advance movement the film part extending from the front top corner to the film outlet 22 is not tensioned but substantially released from tension and it is not retracting into the film outlet 22 because of the operation of the blocking device 49 whereof the guide rollers 50 are only located in the middle part of the film width and not in the random parts provided to laterally project over the article 54. As soon as the article 54 has begun to pass over the film outlet 22 the film part named before will be pulled on the bottom side of the article until it underlaps the film end 57 already and still in place.

Upon further advance movement of the pre-wrapped article 55 the backward end thereof will pass the film outlet 22 and, therefore, a film end 59 will project counter to the advance direction arrow 25 between this backward end and the film outlet 22. After activating the sensor 35 the first time the wrapped article conveyor 24 has started to operate but still the prewrapped article 55 is located at a little distance upstream of the receiving end of this wrapped article conveyor 24 so that time is available to visually control the proper underlapping of the shrinking film under the article 54 and to eventually manually correct the same. Upon a slight further manual advance movement of the pre-wrapped article the front end thereof will frictionally engage the driven conveyor belt 40 of the wrapped article conveyor 24 so that the last sequence of the wrapping operation will be performed automatically upon now driven transport of the pre-wrapped article 55 over the film outlet 22 and the film cutting device 23.

After passing the film outlet 22 the backward end of the wrapped article 55 will pass the sensor 35, thereby activating the same a second time in the above explained manner so that the cutting wire 31 will operate and separate the backward projecting film end 59 from the shrinking film at a distance from the film outlet 22, thereby providing a next starting film end 57 accessibly projecting out of the film outlet 22 for a wrapping operation to take place in a following cycle.

The wrapped article 55 having an only slightly backwardly projecting film end 59 continues to be moved by the wrapped article conveyor 24 until the front end reaches the receiving end 13 of the shrinking path 12 and, therefore, successively is taken over and driven in the same advance direction by the shrinking conveyor 6. The wrapped article 55 will immediately and before having completely left the wrapped article conveyor 24 enter the shrinking station 8, the shrink heaters 10 thereof exerting the shrinking energy characteristic for the shrinking film 56.Thereby during passing the shrinking tunnel 9 the film section 58 wrapped around the article 54 will be laterally and circumferencially intensly shrinked against the outside of the article 54, thereby providing an article enveloped in shrinked film 61 leaving the outlet opening of the shrinking station 8 and being transported to the delivering end 14 of the shrinking conveyor 6 for further automatic transport or manual handling.

For providing a very well functioning transition of the wrapped article 55 from the wrapped article conveyor 24 to the shrinking conveyor 6 two bridging rollers 62 are provided between the delivering end of the wrapped article conveyor 24 and the receiving end 13 of the shrinking conveyor 6, these bridging rollers 62 being of very small diameter smaller than the diameter of the support rollers 27 and circumferencially almost touching the said delivering and receiving ends as well as themselves.

The embodiment according to the invention is useful for different kinds of shrinking films like shrinking films providing only one single layer without any coating.

Too so called skin-films can. be used having a hot seal layer or coating on at least one side like the outer side exposed when wrapped around the article or the inner side covered in the wrapped condition. In each case this coating which provides a lower melting temperature than the main film layer will effect an adhesive connection or fusion seal between at least the overlapping film ends 57, 59 prior to shrinking respective already before separating the film section 58 by means of the film cutting device 23.

Claims (12)

CLAIt5S

1. An apparatus for wrapping articles (54) in shrinking film (56) provided to be shrinked in a condition wrapped at least partially around the article (54), said apparatus comprising: - a wrapping station (20) for delivering said film (56) from a film source (43) in a delivering direction (arrow 26) and for wrapping said film (56) in at least one wrapper turn around each article (54) to provide wrapped articles (55);; - a conveying path provided for bringing each wrapped article (55) to a shrinking station (8), wherein said wrapping station (20) has a wrapping support (21) for advancably supporting each article (54) in the vicinity of a film outlet (22) connected to said film source (43), a film cutting device (23) being provided in an advance direction (arrow 25) of said wrapping support (21) past said film outlet (22), and a wrapped article conveyor (24) being provided for guiding each wrapped article (55) into said shrinking station (8).

2. The apparatus according to claim 1, wherein said wrapping support (21) has an upper support face for the article (54), said film outlet (22) being provided in said support face for predeterminately wrapping said film (56) around said article (54) upon advance movement of the article (54).

3. The apparatus according to claim 1 or 2, wherein said wrapping support (21) is at least partially a roller support, said film outlet (22) being preferably bounded by two adjacent support rollers (27).

4. The apparatus according to one of the preceding claims, wherein said wrapping support (21) is provided for at least initially manually advancing the article (54) to be wrapped, at least one free-wheel support roller (28) only rotatable in the advance direction being provided at least in a beginning portion of said wrapping support (21).

5. The apparatus according to one of the preceding claims, wherein upstream of the film outlet (22) a blocking device (49) is provided for blocking said film (56) against movements opposite to the delivering direction (arrow 26), said blocking device (49) preferably being formed by at least one free-wheel guide roller (50) for guidingly receiving said film (56) on a part of its circumference.

6. The apparatus according to one of the preceding claims, wherein a control device (34) is provided for activating said film cutting device (23) as a function of the position of the wrapped article (55) on the wrapping support (21), said control device (34) preferably comprising an article sensor (35) as a light barrier for the wrapped article (55), said article sensor (35) being located downstream of the film outlet (22).

7. The apparatus according to one of the preceding claims, wherein said wrapped article conveyor (24) is motorized, a control device (34) being provided for activating and stopping said wrapped article conveyor (24) as a function of the position of the wrapped article (55) on the wrapping support (21), said control device (34) preferably being operated by the same sensor (35) as said control device for activating said film cutting device (23).

8. The apparatus according to one of the preceding claims, wherein said apparatus (1) is at least partly a machine unit provided to be secured with respect to a base construction (3) of said shrinking station (8), said wrapped unit conveyor (24) being connectable to a receiving end (13) of a shrinking conveyor (6) of said shrinking station (8).

9. The apparatus according to one of the preceding clains, wherein said apparatus (1) is provided to be attached in a freely projecting manner to said shrinking station (8).

10. The apparatus according to one of the preceding claims, wherein said shrinking station (8) has a shrinking tunnel (9) preferably passed by said shrinking conveyor (6).

11. The apparatus according to one of the preceding claims, wherein means are provided for manually pulling said film (56) available by a projecting film end (57) wider than the article (54) over said article (54) around a backward end and a bottom end thereof, for completing wrapping of the article (54) in a film section (58) of said film (56) by an advance movement (arrow 25) and for separating said film section (58) from said film (56) substantially during said advance movement behind the article.

12. The apparatus according to one of the preceding claims, wherein means are provided for securing at least one film end (57, 59) of said film (56) with respect to the article (54) or to another film end (59, 57) by weight clamping between a bottom face of the article (54) and a support face of the wrapping support (21), means being provided for preferably overlapping said film ends (57, 59) and adhesively connecting them at the latest in the shrinking station (8).

13 The apparatus substantially as herein described and as illustrated in the accompanying drawings.