GB2072727A

GB2072727A - A method of and apparatus for the manufacture of straps

Info

Publication number: GB2072727A
Application number: GB8105646A
Authority: GB
Original assignee: Caristrap Scandinavia AB
Current assignee: Caristrap Scandinavia AB
Priority date: 1980-02-21
Filing date: 1981-02-23
Publication date: 1981-10-07
Also published as: SE8001379L; NL8100871A

Abstract

A method for the manufacture of strap, comprising closely adjacent to each other disposed yarns which are glued together, whereby the yarns are glue soaked and brought together into strap shape whereupon the strap is dried and rolled up. In order to carry out the drying the strap (17) is guided in an arc shaped path at a small distance from a drier which works with high frequency electric or electromagnetic power transmission using a downwardly directed power transmission field, to achieve a high capacity at a low power consumption. An equipment for use in the manufacture of the straps comprises a glueing device (10), a strap forming device (15,16) a drier (19) and necessary cooling and collecting equipment. The drier (19) comprises a high frequency electrical or electromagnetical drier, utilizing a downwardly directed power transmission field, close to the under surface of which the strap (17) is guided. <IMAGE>

Description

SPECIFICATION A method of and apparatus for the manufacture of straps The present invention relates to a method of and apparatus for the manufacture of straps, such as for packing purposes. Straps of the class to which the present invention relates comprise a pulrality of mutually parallel and tightly adjacent to each other disposed yarns, e.g. of polyester, which are glued together e.g. by means of a polyvinylacetate glue, to form a continuous strap.

Hitherto, by the manufacutre of straps of this class, the yarns have been broughttogetherto form a belt which has been soaked with glue to a suitable amount, whereupon the belt has been continuously laid up in a plurality of spaced loops on a rotary reel, from which the belt is also withdrawn continuously.

On the reel the belt is dried, e.g. by means of gas fired free-radiating drying means around the reel.

The manufacture of straps in the just described way is elaborate and requires much skill. Further, this type of manufacture is comparatively expensive, among otherthings because there are big heat losses which moreover give rise to an unsatisfying working environment.

The present invention has for its object to provide a method and meansforthe manufacture of straps of the above mentioned class whereby the just mentioned disadvantages and drawbacks are avoided, at the same time as a not insignificant improvement of the quality of the finished product is achieved.

To the just mentioned end it is proposed that the strap manufacture according to the instant invention should be carried out in such a manner as is defined in principle in the characterizing clause of claim 1.

In accordance therewith it is proposed that the means for the manufacture of the straps should be designed in a mannerto comply with the requirements as set forth in principle in the characterizing clause of claim 2.

The invention will be disclosed in more details below with reference had to the accompanying drawings.

Fig. 1 illustrates diagrammatically one embodiment of an equipment for the manufacture of straps; Fig. 2 illustrates to an enlarged scale and slightly exaggerated the strap path within the equipment in Fig. 1; Fig. 3 illustrates the relationship between the drying electrodes, the strap and a guiding glass rod.

The equipment as shown comprises a glue tray 10 to which a yarn belt 11 is passed through a yarn comb 12 from a yarn spool frame (not shown). The glue tray 10 holds e.g. a water-soluble polyvinyl acetate glue having the proportions 55% dry substance and 45% water. The yarn belt 11 is held down into the glue bath by means of a roll 13 which cooperates with a rubber roll 14to press off excess glue.

From the glue station the yarn belt 11 is passed to a first strap former 15 in the shape of a concave arcuate ceramic bar and a second strap former 16 in the shape of a concave arcuate hard metal bar which also acts as a scraper to remove excess glue. From here the now formed strap 17 is passed beneath a scraper to scrape off any excess glue from the upper surface of the strap, and from that scraper the strap 17 is passed into drying means, generally denoted 19. From the drying means 19 the strap 17 is passed to a calender, generally denoted 20, which also ensures the feeding of the strap, and from there the strap is passed to a chilling zone, generally denoted 21, in this case comprising a fan 22.

The drying means 19 is provided with a plurality of guide members 23 to guide the glue-soaked strap 17 in a generally slightly arcuate path, Figs. 1 and 2. The guide members 23 comprise transverse glass rods, which are spaced longitudinally of the strap 17 and have a diameter of about 20 mm. Preferablythese glass rods are silicone hardened to prevent the glue from adhering thereto. The rods are vertically staggered in such a mannerthatthe angle between the in- and outgoing portions of the strap is always less than 180 . At the inlet end of the drying means the strap 17 is passed below the first rod 23A whereas it is passed over the other rods 23.

At a comparatively small distance above the path of the strap 17 the drying means is provided with a so called RF-drier, generally denoted 24. In this case the expression RF is used to denote "radio fre quency", which means that electric energy of a very high frequency is used, viz. of the order of 25-30 MHz, e.g. 27 MHz.

The RF-drier is equipped with a plurality of transverse electrodes 25, shown in section in Fig. 3, which are mutually interconnected and are connected to a RF-generator (not shown) in any suitable way. As the electrodes 25 are interconnected by means of straight, rigid bus bars it has been found feasible to divide up the electrodes into at least two groups, indicated by the groups 25A and 25B, respectively, in Figs. 1 and 2, to cope with the slightly arcuate path of the strap 17.

In Fig. 3 it has been shown in dashed lines that one of the electrodes 25 may be omitted adjacent each guide rod 23 to give access to the guide rod for cleaning purposes.

In the example shown the arrangement of the electrodes 23 bove the strap 17 results in the formation of a field that goes downwardly through the strap in operation, such as is shown by the field 26 in Fig. 3.

The disposition of the electrodes 23 above the strap 17 results in that short-circuiting is avoided if the strap slackens, if a yarn is broken and hangs downwardly and if the glue drips down into larger amounts. Therefore, the reliability is very high.

It should be mentioned that a strap speed of about 50 met'mien is advantageous by the manufacture of straps from a polyester yarn of a size that gives about 3000 m yarn/kg, and with 20 yarns running mutually parallel, which gives a strap width of about 16 mm. Thereby, the power demand for three straps running parallel to each other through the machine amounts to about 12 kW as contrasted to a power demand of about 84 kW, recalculated from LP-gas to electric power, with the previously known equipments as discussed above, which furthermore are designed for the manufacture of only two parallel straps.

A plurality of modifications and alterations as to details may be carried out within the scope of the invention.

Claims

1. A method of making straps having a plurality of parallel and closely adjacent yarns which are glued together to form a coherent strap, the yarns being soaked in glue and brought together to form a strap which is dried and rolled up, wherein, in order to dry the strap, the strap under at least a slight tension is guided in a slightly arcuate path a small distance beneath a drying means, the drying means working with a high frequency electrical or electromagnetic power transmission using the downwardly directed power transmission field.

2. A method of making straps substantially as herein described with reference to and as illustrated in the accompanying drawings.

3. An apparatus for the manufacture of straps having a plurality of parallel and closely adjacent yarns, the yarnd being glued together to form a coherent strap, comprising gluing means, strap forming means, drying means and cooling and collecting means, wherein the drying means comprises a dryer which works with a high frequency electrical orelectromagnetic power transmission, using a downwardly directed power transmission field, adjacent the under surface of said dryerthe strap being guided under slight tension and in at least a slightly arcuate path.

4. An apparatus for the manufacture of straps substantially as herein described with reference to and as illustrated in the accompanying drawings.

5. A method for the manufacture of straps of the kind which comprise a plurality of parallel and closely adjacrnt each other disposed yarns which are glued together to form a coherent strap, whereby the yarns are soaked in glue and brought together to form a strap which is dried and rolled up characterized in that the strap, to effect the drying step, under at least a slight tension is guided in a slightly arcuate path at a small distance beneath a drying means which works with high frequent electrical or electro-magnetical power transmission using a downwardly directed power transmission field.

6. A means for the manufacture of straps of the kind which comprise a plurality of parallel and closely adjacent each other disposed yarns which are glued together to form a coherent strap, comprising a glueing means, strap forming means, a drying means and necessary cooling and collecting means, characterized in that the drying means comprised a drier which works with high frequent electrical or electromegnetical power transmission, using a downwardly directed power transmission field, adjacent the under surface of which drier the strap is guided under slight tension and in an at least slightly arcuate path.