GB2249782A

GB2249782A - Web feeding mechanism

Info

Publication number: GB2249782A
Application number: GB9125020A
Authority: GB
Inventors: Yoshikazu Sato; Tamio Uchida
Original assignee: Tokyo Automatic Machinery Works Ltd
Current assignee: Tokyo Automatic Machinery Works Ltd
Priority date: 1990-11-19
Filing date: 1991-11-19
Publication date: 1992-05-20
Anticipated expiration: 2011-11-19
Also published as: KR950010678B1; MY106901A; KR920009672A; AU8792691A; JP2903496B2; JPH04182250A; SG30585G; AU641060B2; CN1061756A; GB9125020D0; HK183995A; GB2249782B; CN1026400C

Abstract

Web, drawn intermittently from roll A, e.g. by packaging apparatus D, is formed into a U-shape in suction device C, which includes a loop sensor 3a controlling a device i which feeds web to device C. The vertical extent of the U-shape is thus kept constant and web tension downstream of device G is controlled. Device C comprises a rectangular-section, open-topped box, suction being applied at port 2b. The distance between the box side walls, i.e. those which extend parallel with the web, is adjustable to match the width of the web. The packaging apparatus is stopped when a second loop sensor 3b detects an abnormally small U-shape. <IMAGE>

Description

TITLE OF THE INVENTION WEB SUPPLYING DEVICE BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a web supplying device in which a web supplied from a web roll under an intermittent operation of a feeding mechanism is fed out by a predetermined length and a preliminary feeding mechanism for drawing the web from the web roll to be operated in response to an intermittent feeding-out operation of the web is arranged in the midway part of the feeding-out passage.

Description of the Prior Art As a conventional type of web supplying device, there is provided, as disclosed in Japanese Patent Laid Open No.Sho 62-158629, for example, wherein a preliminary feeding-out mechanism which has preliminary feeding-out rollers and tension levers swingably arranged at a downstream side of the preliminary feeding-out rollers is installed in the midway of the feeding-out passage ranging from the web roll to a tube forming body; the web is applied over a plurality of rotatable tension rollers pivotally supported on the tension levers and a plurality of guide rollers arranged to be oppositely against each of these tension rollers; thereby a specified tension is applied to the web with the weights of the tension levers or the tension rollers; at the same time when the web is intermittently fed out by a predetermined length under an intermittent operation of the feeding-out mechanism, the web is detected by sensors to rotationally operate the preliminary feeding-out rollers to cause the web to be pulled out of the web roll and to return the tension levers to their initial states, resulting in that a force for pulling out the web from the web roll is reduced and the web is always tensioned and suspended.

SUMMARY OF THE INVENTION However, in case of such a conventional type of web supplying device described above, the tension levers are oscillated at a speed corresponding to the intermittent feeding-out speed of the web, so that if the web is intermittently fed out at a high speed in particular, a certain inertia is applied due to the weights of the tension levers and the tension rollers when the tension levers are oscillated so as to cause them to oscillate more than a required angle.Then a delay in follow-up may occur in respect to the fed-out web and at the same time the web is applied through a plurality of tension rollers and the guide rollers accompanied by the feeding-out operation of the web, resulting in that if the web is intermittently fed out at a high speed in particular, it shows a phenomenon that the web is fed out more than that required due to a rotational inertia of these several driven rollers and returned.As a result, a loosened condition of the web in which no tension is exerted thereon at all may easily be generated, a displacement of the web in a widthdirection perpendicular to a feeding-out direction of it may be produced, or in the event that some registration marks are applied to the web for every interval and a positioning of the web is performed on the basis of the registration marks so as to align the marks in the web, it shows a problem that a positioning accuracy is reduced.

In addition, since there are many extreme bent portions of the web formed by several driven rollers, there is a problem that a winding of the web around the driven rollers is poor and a uniform tension may not be applied to an entire web if the web has a resilient material quality and the web is hard and there is also a problem that a web applying operation over many driven roller is a troublesome work.

In view of the circumstances in the prior art described above, it is an object of the present invention to apply the web while the bent portions being reduced without having any inertia member and to apply always a uniform tension to the web in a lateral direction of the web in such a way as the web may not be moved.

The technical means provided by the present invention in order to resolve the aforesaid problems is characterized in that a suction mechanism for sucking the web to loosen it into a U-shape form is arranged at a downstream side of the preliminary feeding-out mechanism, an operation of the preliminary feeding mechanism is controlled in response to a variation of a looseness length of the U-shaped web and at the same time the guide faces abutting against each of both side edges in a width direction of the U-shaped web are oppositely arranged.

It is preferable that the aforesaid suction mechanism is comprised of a box-like suction chamber having an opening at one end thereof to which the web is fitted and having a suction port at the other end surface and sensors for sensing a looseness length of the U-shaped web fitted from the opening into the suction chamber, an operation of the preliminary feeding-out mechanism is controlled in response to an output from each of the sensors, a looseness length of the U-shaped web is kept at its specified length and at the same time the guide surfaces opposing onto the suction chamber are formed while being approximately equally spaced apart as the width size of the web.

In addition, the aforesaid web supplying device suspends the web supplied from the web roll through a tube forming member to form into a cylinder, seals the web through a closing operation of a lateral sealing machine to form a bag member and acts as a web supplying device in a bag forming, filling and packaging machine for filling packaged substance into the bag. The feeding-out mechanism can be arranged at the downstream side of the tube forming body.

According to the aforesaid technical means, the present invention is operated such that the web is sucked under an operation of the suction mechanism to cause the web to be loosened into a U-shape, thereby a specified tension is given to the web, the U-shaped web is positioned along the opposing guide surface as the web is intermittently fed out in its width direction and pulled out of it, the looseness length of the U-shaped web is varied to control an operation of the preliminary feeding-out mechanism and then the looseness length of the U-shaped web is kept constant.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.l is a front elevational view for showing a web supplying device to illustrate one preferred embodiment of the present invention.

Fig.2 is a partial enlarged top plan view with a part broken way taken along a line (II)-(II) of Fig.l.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, one preferred embodiment of the present invention will be described as follows.

As shown in Fig.l, this preferred embodiment is constructed such that a suction mechanism C composed of a suction chamber 2 and sensors 3 is arranged in the feeding-out passage B ranging from the web roll A to the tube forming body D1 of a bag forming, filling and packaging machine D. A feeding-out belt acting as a feeding-out mechanism E is arranged at a downstream side of the tube forming body D1 in opposition to an outer surface of the bag forming cylinder D2 of the bag forming, filling and packaging machine D and then the web W is fed out by a predetermined length in a web W withdrawing direction of the preliminary feeding-out mechanism 1 comprised of the feeding-out rollers, for example, under an intermittent operation of the feedingout mechanism E.

The suction chamber 2 is divided into a longitudinal box-like segments with a plurality of flat places, its upper surface is opened, each of a pair of opposed opening edges toward the feeding-out direction of an opening 2a in an arcular longitudinal section and the web W applied over both arcular edges 2al and 2a along the feeding-out passage B to form a U-shape.

A suction port 2b is opened at the lower surface of the suction chamber 2, and then an interior part of the suction chamber 2 is communicated with a suction source 2c having a large suction flow rate such as a sirocco fan or the like arranged outside the suction chamber 2 through the suction port 2b.

The suction port 2b has an aeration means 2bl such as a sponge, for example, around it to be projected into the suction chamber 2, a net 2b2 is laterally arranged over the upper plane of the suction port, thereby a sucking of the web W into the suction port 2b is prevented and at the same time even if the web W is erroneously sucked into the suction chamber, the air can be suctioned, an opening area of the air discharging port 2cl of the suction source 2c can be adjusted to enable a suction force to be adjusted in response to a variation of a width size of the web W.

Each of guide surfaces 2d, 2d opposing in a direction perpendicular to a feeding-out direction of the suction chamber 2 is formed with slant portions 2d1, 2d1 gradually projecting into the suction chamber 2 as they are directed downstream side in the feeding-out direction. Inner width size (w) at the downstream side is made approximately equal to a width size of the web W.Each of the guide surfaces 2d, 2d is abutted against both side edges W2, W2 in a width direction of the Ushaped web W1 drawn out of the web roll A so as to to correct a displacement of the web W toward its width direction and simultaneously both flat plates forming the guide surfaces 2d and 2d or either one of them is movably supported in a width direction of the web W, and both guide surface 2d, 2d or one side surface is moved by an adjusting means 2d such as a manual handle, for example, so as to accommodate for a variation in a width size of the web W.

In addition, the side surface ranging from the opening 2a to the suction port 2b is provided with sensors 3 for use in detecting a loosened length of the U-shaped web W1 fitted into the suction chamber 2 and controlling an operation of the preliminary feeding-out mechanism 1.

In case of the preferred embodiment, two sensors 3 are buried at upper and lower sides of an intermediate part of the guide surface 2e located at a downstream side in a feeding-out direction in a properly spacedapart relation in a vertical direction toward the Ushaped web W1. Under a non-detected case in which the lower end position of the U-shaped web Wl is moved more upwardly than its set position as an intermittent operation of the feeding-out mechanism E, the lower sensor 3a starts an operation of the preliminary feeding-out mechanism 1, and in turn, under a sensing state in which the lower end position of the U-shaped web W1 is moved more downwardly than its set position, the lower sensor 3a stops an operation of the preliminary feeding-out mechanism 1.The upper sensor 3b is used for sensing an abnormal operation so as to stop an operation of the feeding-out mechanism E only when the sensing is not carried out.

Reference numeral 4 in the drawing denotes sensors for use in sensing some registration marks, and a reference symbols F denotes lateral sealing machine.

In this way, the web supplying device applies a constant tension force to the web W by a method wherein air in the suction chamber 2 is sucked from the suction port 2b and the web W is sucked into the suction chamber 2 in a form of U under a negative pressure generated as the air is suctioned.

Under this state, the predetermined length of the web W is pulled out toward the downstream side in a feeding-out direction under an intermittent operation of the feeding-out mechanism E, thereby as the lower end position of the U-shaped web W1 fitted into the suction chamber 2 is moved upwardly to cause a looseness length to be shortened, resulting in that this state is detected by the lower sensor 3a to start an operation of the preliminary feeding-out mechanism 1, the web W3 pulled out of the web roll A is fed out toward the suction chamber 2, the lower end position of the Ushaped web W1 is moved downwardly and then a looseness depth or length of the web is gradually increased.

When the looseness length of the U-shaped web W1 reaches the lower sensor 3a and this state is detected by the sensor 3a, operation of the preliminary feedingout mechanism 1 is stopped and then a looseness length of the U-shaped web W1 is kept constant.

Subsequently, every time the feeding-out mechanism E is intermittently operated, the aforesaid operation is repeated.

A structure of the aforesaid suction chamber 2 is not limited to one illustrated in the drawing. Although both arcular edges 2ai, 2ai opposing toward the feedingout direction, for example, are formed at the same height positions, the arcular edge 2ai at the upstream side in the feeding-out direction is formed at a lower position as compared with that of the arcular edge 2ai at the downstream side, thereby a sucking of the web W supplied from the preliminary feeding-out mechanism 1 is facilitated and at the same time a contact area between the side surface 2e at the downstream side and the Ushaped web Wl is widened to increase their friction so as to utilize it as a brake for preventing a running of the U-shaped web W1.

Since the present invention is constructed as above, it has the following advantages.

O )The web is sucked as an operation of the sucking mechanism is carried out so as to loosen it into a U shape, thereby a specified tension force is applied to the web, the U-shaped web is positioned in its width direction along the opposing guide surface as the intermittent feeding-out operation of the web is performed, and is pulled out, and at the same time a looseness length of the U-shaped web is varied to control an operation of the preliminary feeding-out mechanism and then the looseness length of the U-shaped web is kept constant, so that the web can be applied over it without any inertia member while reducing an extreme bent portion and then the tension can always be applied uniformly in such a way as it may not be moved in a width direction of the web.

Accordingly, as compared to the conventional type in which there are many extreme bent portions and a tension force is applied to the web applied over it through an inertia member such as tension levers or several driven rollers or the like, even if the web is intermittently fed out at a high speed, a loosened condition of the web in which no tension is supplied thereto at all can be completely prevented and so the web does not generate any displacement in a width direction and further in case that the patterns of the web are aligned to each other, a positioning accuracy is improved. In addition, even if material quality of the web has a certain resiliency, a uniform tension can be given to the entire web and so the web applying operation can be simply performed.

9 As the tension force is increased in order to prevent a looseness of the web, an intermittent feedingout force must correspondingly be increased. However, the web supplying device of the present invention can prevent any looseness of the web completely, so that the tension to be applied to the web can be set as less as possible and along with this effect, the feeding-out force may also be saved and a driving source for performing the feeding-out operation can be made small in size.

9 Since the web is sucked, dusts adhered on the surface of the web or the like can be removed and then the web may easily be fed out.

Claims

What is claimed is:

1. A web supplying device in which a web supplied from a web roll is fed out by a predetermined length under an intermittent operation of a feeding-out mechanism and a preliminary feeding-out mechanism for drawing out the web from the web roll as the intermittent feeding-out of said web is operated is arranged in the midway of a feeding-out passage characterized in that a suction mechanism for sucking the web and loosening it into a Ushape is arranged at a downstream side of said preliminary feeding-out mechanism, the preliminary feeding-out mechanism is controlled for its operation in response to a variation of the loosened length of the Ushaped web and the guide surfaces abutting against each of both side edges in a width direction of the U-shaped web are oppositely arranged.

2. A web supplying device according to Claim 1 in which said suction mechanism is comprised of a box-like suction chamber having an opening at its end surface to which the web is fitted and a suction port at its other end and sensors for sensing a loosened length of the Ushaped web fitted from the opening into the suction chamber, the preliminary feeding-out mechanism is controlled for its operation in response to an output from each of the sensors, the loosened length of the Ushaped web is kept at its specified length and at the same time the guide surfaces opposing onto the suction chamber are formed in approximately the same spacing as a width size of the web.

3. A web supplying device in a forming, filling and packaging machine according to Claim 1 or 2 in which said web supplying device suspends the web supplied from the web roll through the tube forming body while forming a cylinder, the web is sealed in a width direction under a closing action of a lateral sealing machine and then the packaged item is filled in said bag, wherein the feeding-out mechanism is arranged at a downstream side of the tube forming body.