System for regulating the feed of articles to a wrapping machine

Abstract

 The invention relates to a system for regulating the feed of articles to a wrapping machine, of the type comprising means (9) for advancing longitudinally a wrapping strip (2) which bears a series of marks spaced longitudinally from each other, and first sensor means (22) arranged to detect the passage of the marks and provide signals indicative of the positions of the strip at predetermined instants. The system includes conveyor means (24) for feeding a series of articles (11) spaced longitudinally from each other to the wrapping machine, second sensor means (27) arranged to provide signals indicative of the position of the articles (11) on the said conveyor means (24) and control means (26) for varying the speed of the conveyor means (24) in dependence on output signals from the second sensor means (27) so as to feed the articles (11) to the wrapping machine in a predetermined phase relationship with the said wrapping strip (2). According to the invention, the second sensor means (27) are actuated by output signals from the first sensor means (22) whereby the output signals from the second sensor means are indicative of any deviation of each article from the correct position in phase with the wrapping strip.

Description

[0001] The present invention relates to a system for regulating the feed of articles to a wrapping machine, in which this wrapping machine includes means for advancing longitudinally a wrapping strip which bears a series of marks spaced longitudinally from each other, and first sensor means arranged to detect the passage of the said marks to provide signals indicative of the positions of the strip at predetermined instants, the said system including:

- conveyor means for feeding a series of articles spaced longitudinally from each other to the wrapping machine;

- second sensor means arranged to provide signals indicative of the position of the articles on the said conveyor means, and

- control means for varying the speed of the conveyor means in dependence on output signals from the second sensor means, so as to feed the articles to the wrapping machine in a predetermined phase relationship with the said wrapping strip.

[0002] Systems of the aforesaid type are already in use in which a bladed conveyor is provided at the input end of the wrapping machine to receive the articles from the said conveyor means and feed them to the wrapping machine. In these known systems, the signals provided by the second sensor means are used to "phase" the articles fed by the conveyor means with the said bladed conveyor, while the signals provided by the said first sensor means are used to "phase" the wrapping strip relative to the bladed conveyor. In further detail, in these known systems, the output signals from the second sensor means are fed to the control means which, if necessary, vary the speed of the conveyor means to allow each article to be brought exactly into engagement with the respective blade of the bladed conveyor. The output signals from the first sensor means are instead used to check that the movement of the wrapping strip is always in phase with the movement of the bladed conveyor.

[0003] The requirement of feeding the articles to the wrapping machine in a predetermined phase relationship with the paper strip results from the fact that this strip receives particular graphics (writing, designs and the like) in correspondence with each article to be wrapped, which must be "centered" relative to the article when the latter is wrapped.

[0004] The object of the present invention is to provide a system for regulating the feed of articles to a wrapping machine which is simpler and more practical than the known solutions described above.

[0005] In order to achieve this object, the invention provides a regulating system the main characteristic of which lies in the fact that the said second sensor means are actuated by output signals from the said first sensor means, whereby the output signals from the second sensor means are indicative of any devration of each article from the correct position in phase with the wrapping strip of the wrapping machine.

[0006] By virtue of the

the system according to the present invention, the output signals from the first sensor means, containing the "information" from the wrapping strip, are used directly to "phase" the articles carried by the conveyor means with respect to the wrapping strip, wherein it differs from the known systems in which the "phasing" of the articles relative to the wrapping strip is achieved by "phasing" both the articles and the wrapping strip relative to the bladed conveyor.

[0007] The system according to the invention thus allows the elimination of the need for this bladed conveyor. Furthermore, since the "phasing" of the articles relative to the wrapping strip is achieved by using the "information" from the wrapping strip directly, it is no longer necessary to provide for varying the speed of the wrapping strip. This avoids the need to use an adjustable mechanical transmission for driving the wrapping strip, wherein it again differs from known devices.

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[0008] In a preferred embodiment of the system according to the present invention, the said second sensor means are also arranged to indicate the degree and direction of any deviation of each article from the correct position in phase with the wrapping strip, and the said control means are arranged to correct the speed of the conveyor means to an extent proportional to the degree of deviation detected.

[0009] Further characteristics and advantages of the present invention will emerge from the description which follows with reference to the appended drawings, provided purely by way of non-limiting example, in which:

Figures 1 and 2 are respectively schematic side elevational and plan views of a wrapping machine provided with a regulating system according to the present invention;

Figure 3 is a section taken on the line III-III of Figure 1;

Figure 4 illustrated in perspective and on an enlarged scale a detail of Figure 1, and

Figures 5 and 6 are perspective views of a wrapped article of the type obtained at the output of the wrapping machine illustrated in Figures 1 and 2.

[0010] In the drawings, reference numeral 1 generally indicates a wrapping machine using a paper strip 2 which unrolls from a feed roller 3 to form the wrappers for the articles.

[0011] As the paper strip 2 unwinds from the roller 3, it is folded so as to bring its two longitudinal edges 4 (see Figure 4) into contact with each other, to form a tube 5 having underneath an external longitudinal fin 6 constituted by the two longitudinal edges 4 which are juxtaposed.

[0012] As illustrated in Figures 3 and 5, the paper tube 5 is supported by two longitudinal supports 7 having opposed L-shaped cross-sections which together define a longitudinal slot 8 through which the fin 6 projects.

[0013] The wrapping machine is provided with a series of pairs of wheels 9 driven by an electric motor (not illustrated), which engage the two sides of the longitudinal fin 6 to join the longitudinal edges 4 of the paper strip together and draw the paper tube 5 in its longitudinal direction.

[0014] Immediately upstream of the forming end of the paper tube 5 is located the discharge end of a belt conveyor 10 which feeds a series of articles 11 to be wrapped, which are spaced longitudinally from each other, into the paper tube 5. The speed of the conveyor 10 is substantially the same as that of the movement of the paper tube 5. The articles 11 are deposited on the lower part of the-internal surface of the paper tube 5 (see Figure 3) and are drawn by the latter towards two contra-rotating jaws 12 (see Figure 1) of the type known per se which join together the walls of the paper tube in the zone immediately between one article and the next and separate the successive articles from each other.

[0015] Figures 5 and 6 illustrate the wrapped article obtained. In these Figures, reference numeral 14 generally indicates the wrapper of the article, while reference numeral 15 indicates each of the two transverse fins obtained as a result of the joining and cutting effected by the jaws 13. Reference numeral 16 shows the lower longitudinal fin corresponding to the section of the fin 6 which is separated from the paper tube by the jaws 13. The article is then sold in the condition illustrated in Figure 6, that is, with the fin 16 folded so as to be parallel and adjacent the lower surface of the package.

[0016] In Figure 1, a conveyor device, schematically shown as 17, is disposed downstream of the jaws 13 and receives the wrapped articles from these jaws, conveying them to the output of the wrapping machine.

[0017] As illustrated in Figure 5, the wrapper 14 of each article bears specific graphics 18 (for example, writing or a design) which must be "centered" relative to the article itself. Consequently, the articles 11 must be fed into the paper tube 5 which bears the succession of graphics 18, in a predetermined phase relationship.

[0018] Wrapping machines of the type described above are known and are called "fin-seal" wrapping machines in this branch of the art.

[0019] In fin-seal machines made until now, the "phasing" of the articles relative to the paper tube is achieved as follows:

Immediately upstream of the paper tube there is a bladed conveyor which is driven by the same motor as drives the wheels for drawing the paper tubes. Between the motor and these wheels is connected an adjustable mechanical transmission which allows the speed of movement of the paper tube to be varied. Moreover, a series of longitudinally-spaced centering marks is provided on the paper strip 2, the passage of which is detected by a sensor, normally a photoelectric cell. The output signals from this sensor device are used to ensure that the drive for the paper strip is always in phase with the drive for the bladed conveyor upstream of the paper tube. It is then necessary to provide regulating systems upstream of the bladed conveyor to ensure that each article fed to this bladed conveyor is brought precisely into engagement with the respective blade.

[0020] Regulating systems of this type are illustrated, for example, in Italian Patent Application No. 67656/79 by the same Applicant and in Italian Patent Application No. 29219/72.

[0021] In the system according to the invention, the use of the said bladed conveyor is avoided, as is also the use of the said adjustable mechanical transmission between the wheels 9 and the motor which drives them. Indeed, the translational speed of the paper tube 5 never varies.

[0022] In the system according to the present invention, the paper strip 2 is still provided with a series of centering marks. In particular, at least one of the two longitudinal edges 4 (see Figure 4) -of the paper strip 2 bears a series of marks 19 of a material or colour which is different from that of the remaining part of the strip, which gives rise to the same number of centering marks 21 on the longitudinal fin 6 of the paper tube. The wrapping machine further includes a sensor device 22 arranged to detect the passage of the marks 21. In the example illustrated, the sensor device 22 is constituted by a photoelectric cell cooperating with a device 23 arranged to direct light onto it.

[0023] Upstream of the forming end of the paper tube 5 are provided conveyor means 24 (see Figures 1 and 2) which, in the example illustrated, comprise the above- mentioned belt conveyor 10 and, upstream thereof, an accumulation belt conveyor 25 on which the articles 11 intended to be fed to the wrapping machine are accumulated. The belt conveyor 10 moves at a speed greater than that of the belt conveyor 25, so as to cause the spacing of the articles 11 from each other, and has a length such that there is never more than one article present thereon.

[0024] In order to allow "phasing" of the articles 11 relative to the paper tube 5, the sensor device 22 is connected to control means 26 which are also connected to sensor means 27 associated with the belt conveyor 10. The control means 26 are finally connected to a motor 40 (indicated schematically in Figure 2) which drives the movement of the belt conveyor 10.

[0025] The control means 26 are arranged to actuate the sensor means 27 when the sensor device 22 detects the passage of a centering mark 21. (Here the expression "actuation of the sensor means" is intended to refer both to the case of proper actuation of these sensor means and to the case in which the sensor means are in fact always active, the "actuation" mentioned above consisting of comparing the output signal from the sensor means with a predetermined threshold signal). By virtue of this arrangement, it is possible to check whether a given article 11 on the belt conveyor 10, at a particular instant corresponding to a predetermined position of the paper tube 5, is in the correct position in phase with the paper strip or not.

[0026] When the sensor means 27 signal that the article has deviated from its correct position, the control means 26 act on the motor 40 to vary the speed of the belt conveyor 10 so as to correct and take up this deviation.

[0027] In the particular example illustrated, the sensor means 27 are constituted by four photoelectric cells 28, 29, 30, 31 in longitudinal alignment with each other. Thus, it is possible to provide an indication of the direction and degree of any deviation of each article from the correct position. It should be assumed that, for example, at the instant in which the sensor device 22 detects the passage of a centering mark 21, that is, at the moment of the activation of the photoelectric cells 28 to 31, an article 11 should, to be correctly in phase with the paper tube 5, have its front end located between the cell 29 and the cell 30. In this situation, the cells 28, 29 should be obscured while the cells 30, 31 should be clear. If the cells 30, 31 are also obscured this indicates that the article 11 is ahead, the degree to which it is ahead being less if only the cell 30 is obscured and the cell 31 is clear and greater if both the cells 30, 31 are obscured. Similarly, any delay of the article 11, and the degree of this delay, is indicated by the fact that the cell 29 (and possibly also the cell 28) is clear.

[0028] In this particular embodiment, the control means 26 are arranged to correct the speed of the motor 40 proportionally to the degree of deviation detected by the sensor means 27.

[0029] The same result would be achieved by using a single photoelectric cell instead of the cells 28 to 31, and arranging a series of centering marks on the paper strip in correspondence with each article so as to actuate the said photoelectric cell several times in correspondence with the passage of each article.

[0030] Finally, it is also possible to achieve a combination of the two systems, that is, to provide the photoelectric cells 28, 29, 30, 31 and to actuate these photocells several times in correspondence with the passage of each article by means of a series of corresponding centering marks provided on the paper strip.

[0031] Obviously, the sensor means 27 may be constituted by any number of photocells, the precision of the indication of the degree of deviation from the correct position of each article being greater the greater this number.

[0032] Moreover, it is possible to provide several belt conveyors of the same type as the conveyor 10 disposed one downstream of the other and each provided with sensor of the same type as the sensor means 27, so as to allow the detection of any deviation from the correct position to be repeated one or more times on a single article in the course of its movement. This allows the checking of the result of a previous action and the possible improvement of this correction.

[0033] In view of what has been said above, it is clear that the general idea which is at the basis of the present invention lies in the direct use of the "information" formed on the paper strip (that is, the signals provided by the reading of the marks of the strip) for the "phasing" of the articles relative to the paper strip.

Claims

1. System for regulating the feed of articles to a wrapping machine, in which this wrapping machine (1) includes means (9) for advancing longitudinally a wrapping strip (2) which bears a series of marks (21) spaced longitudinally from each other, and first sensor means (22) arranged to detect the passage of the said marks (21) to provide signals indicative of the position of the wrapping strip at predetermined instants, the system including:

- conveyor means (24) for feeding to the wrapping machine (1) a series of longitudinally-spaced articles (11);

- second sensor means (27) arranged to provide signals indicative of the position of the articles (11) on the said conveyor means (24), and

- control means (26) for varying the speed of the conveyor means (24) in dependence on output signals from the second sensor means (27) so as to feed the articles (11) to the wrapping machine in a predetermined phase relationship with the said paper strip (6),

characterised in that the second sensor means (27) are actuated by output signals from the first sensor means (22), whereby the output signals from the second sensor means (27) are indicative of any deviation of the articles (11) from the correct position in phase with the wrapping strip (2).

2. System according to Claim 1, characterised in that the second sensor means are constituted by a single sensor device, in that the wrapping strip is provided with a series of reference marks for each article to be wrapped to actuate successfully the said sensor device in correspondence with the passage of each article (11), so as to obtain at the output of the sensor device a series of signals which contain information of the degree and direction of any deviation of the article (11) from the correct position in phase with the wrapping strip, and in that the control means (26) are arranged to correct the speed of the conveyor means (24) in proportion to the degree of deviation detected.

3. System according to Claim 1, characterised in that the second sensor means (27) are constituted by a series of sensor devices (28 - 31) which are longitudinally spaced from each other that the wrapping strip is provided with a reference mark for each article to be wrapped to actuate simultaneously the said sensor means (28 - 31) in correspondence with the passage of each article, so as to obtain at the output of the sensor devices (28 - 31) a series of signals which contain the information of the degrees and direction of any deviation of the article (11) from the correct position in phase with the wrapping strip, and in that the control means (26) are arranged to correct the speed of the conveyor means (24) in proportion to the degree of deviation detected.

4. System according to Claim 1, characterised in that the second sensor means (27) are constituted by a series of longitudinally-spaced sensor devices (28-31), in that the wrapping strip is provided with a series of marks for each article to be wrapped to actuate the said sensor devices several times, each time simultaneously, in correspondence with the passage of each article, so as to obtain at the output of these sensor devices (28 - 31) a series of signals which contain the information of the degree and direction of any deviation of the article (11) from the correct position in phase with the wrapping strip, and in that the control means (26) are arranged to correct the speed of the conveyor means (24) in proportion to the degree of deviation detected.

5. System according to Claim 1, characterised in that the conveyor means (24) are associated with different sensor means spaced longitudinally from each other, to allow the detection of any deviation from the correct position in phase with the wrapping strip to be repeated one or more times on each article (11) during the course of its movement.

Drawing