GB1586832A - Hollow cylindrical spool or package of thread - Google Patents

Description

(54) A HOLLOW CYLINDRICAL SPOOL OR PACKAGE OF THREAD (71) We, SAINT-GOBAIN INDUSTRIES, a French body corporate, of 62 Boulevard Victor-Hugo, Neuilly-Sur-Seine, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a hollow cylindrical spool or package of wound thread, hereinafter simply called a spool, having an outer covering. The thread may be for example continuous glass thread treated with a sizing or a brightening agent, which threads are wound as strand or as roving in successive layers and are drawn off from the interior or centre of the spool. The invention relates in particular to a means of wrapping spools to enable them to be transported, treated or further processed.

The tension which builds up between the different layers of thread when winding the strand or roving is sufficient to make a spool self-supporting. The thread can be drawn off either from the outside or from the centre of the spool, but if it is drawn off from the outside, the spool must be removed from its container which has been provided for transport.

Moreover, the strand or roving is liable to billow and catch if it is drawn off from the outside over the edge of the spool. For this reason, processers generally prefer a spool to be wound so as to be drawn off from the interior, that is, from the centre of the spool. It is customary to attach the end of a strand or roving of one spool to the beginning of the next to render operation continuous.

Spools of glass rovings have hitherto customarily been loosely wrapped in polyethylene or paper bags to protect them against dirt, moisture and some friction, without affecting the case with which the rovings can be drawn off the spools. Depending on the sizing or the brightening agent applied to the glass threads during their manufacture, on the hardness and thickness of the threads, on the spool winding, and on density of winding and make up of the spools, the outer layers of threads tend to collapse in the course of draw off from the centre because at some stage they no longer retain the self-supporting cylindrical form. The layers can then become entangled and a knot forms so that the operator must stop production to disentangle the knotted portion or remove it if disentanglement is no longer possible or economical.

Considerable portions of the spools can in this way be discarded as rejects. This phenomenon is more marked the thicker and harder the threads, the more open the roving, the softer the spool winding, and the larger the spool diameter. However, it is precisely this arrangement of hard, thick threads relatively softly wound so that they readily fall apart on cutting, combined with as large a spool diameter as possible in order to obtain long runs, which is currently being demanded to an increasing extent by thread processors.

Attempts have therefore been made to improve draw off of the roving strands and transition from one spool to the next. With this in view, spools have been after treated in air ovens or high frequency ovens, but, apart from its additional cost, such after treatment has the disadvantage of altering the character of the threads as well as causing more or less pronounced sticking of the roving strands, which has a deleterious effect on the cutting properties.

According to another proposal (see German Patent Specification No. 2,204,891), an outer covering consisting of a synthetic resin is provided in close but not adherent contact with the outer layer of the spool, this outer layer together with the covering being sufficiently self-supporting after removal of the inner layers. This covering consists of a synthetic resin foil which is shrunk onto the roving package under heat. Shrinking of a roving package in a shrunk-on foil causes additional cost and improves only the draw off characteristics of those qualities of roving which are less sensitive in this respect, whereas relatively softly wound roving strands of thick, hard threads dressed with a nonsticking sizing or brightening agent slip off the smooth internal surface of the shrunk-on foil.

It is also known (see U.S. Patent Specification No. 3,731,792) to, provide a highly vis cous, adhesive liquid with a yiscosity of from 700 to 5,000 poises between the roving spool and an external covering. This adhesive liquid may be applied either to the surface of the spool or to the surface of the covering adjacent the outer windings of the spool. The liquid penetrates the gaps between the fibres of the outer windings of the spool and these windings then adhere to the covering so that they stay in position even when the other layers of the spool have been drawn off, but they cannot be removed from the covering without the fibres being damaged or the layers of roving becoming entangled. This technique also gives rise to problems such as the need to choose an adhesive liquid which is not only suitable for the purpose and compatible with the resin with which the roving is to be subsequently processed, but provides sufficient bonding power even under altered environmental conditions. Moreover the liquid produces additional resistance to drawing off of the roving so that it is not always possible to prevent the outer layers from sticking and being damaged during the draw off operation.

It is an object of the invention to provide means whereby a material in the form of a thread wound on a spool, for example continuous glass threads or glass rovings, can be drawn off from the centre of the spool to the end or to the transition to the next spool, without undue difficulty.

According to this invention there is provided a hollow cylindrical spool of thread having an outer covering comprising, at least at its surface facing the thread, an elastomeric material having surface irregularities or cavities, which material encloses the outer layer of winding of the spool under tension and penetrates gaps between the threads of said outer layer.

Due to the formation of the covering in accordance with the invention and the pressure which it exerts on the surface of the gaps, as well as due to the relaxation of the last layers of winding drawn off from the outer surface of the spool, which results in a degree of counter pressure of these layers against the covering, the elastomeric covering material supports the outer layer against slipping down, so that the last, outermost layers of winding remain fixed in their hollow cylindrical form and are drawn off from this position without slipping down and becoming entangled with each other. The thread may thus be completely drawn off without interruption in the last, outermost layers, and proper transition to the next spool becomes possible.

The material of the covering may be plastics foam, preferably a coarse-celled polyurethane foam. This elastomeric and porous material is particularly suitable as covering for roving spools. In addition, it has the advantage of good weathering resistance and heat resistance so that even if spools are stored for considerable periods in a moist or warm atmosphere there is little risk of the properties of the covering undergoing adverse changes liable to impair unwinding.

Foam rubber having surface cavities or irregularities is also suitable for use as the covering material.

The covering material may be a composite, for example an elastomeric foamlpaper laminate. In such a case at least that surface of the covering which faces the spool is formed by the elastomeric foam material which has a degree of roughness or irregularity so that, as it engages the outer layer under tension it can penetrate the gaps and spaces between the threads and winding of the outer layers of the spool. This penetration of the covering material into the gaps and spaces between the threads and layers of winding produces a supporting and holding effect which fixes the outermost layers in position as a thin-walled tube and prevents them slipping downwards.

The strand of roving is drawn off from this fixed position without becoming hooked up or entangled and without sticking or being damaged by rubbing against the covering material. The covering itself remains as a tubular structure when the roving spool is empty.

The amount of tension which must be exerted on the covering material to enable it to exert a pressure on the outer layers of the spool can be produced by winding a strip of paper round the covering after it has been placed on the spool, and fixing the paper strip firmly with two strips of adhesive. Instead of using a paper strip, a bag of paper or foil open at one end may be placed over the covering on the spool and may then be fixed so as to lie firmly on it, by means of adhesive tape. If a relatively thick covering material is used, the tension may be produced directly by wrapping two strips of adhesive tape round the covering.

The operation of placing the covering on the spool and then fixing it tightly in position by tape may be carried out on an upright winding head, on a work plate or on a pallet.

The invention will now be described by way of example with reference to the drawing, in which: Figure 1 is an axial section of an embodiment of a covered, relatively small spool suitable for continuous unwinding of several spools in a row; Figure 2 is a side elevation of the covered spool of Figure 1; Figure 3 is a top plan of the spool of Figure 1; Figure 4 is an axial section of another embodiment of a larger covered spool which may be connected to other spools for continuous unwinding; Figure 5 is a side elevation of the spool of Figure 4; and Figure 6 is a top plan of the spool of Figure 4.

A spool or package 1 (Figs. 1 to 3) comprises a glass roving which in turn comprises a plurality of spun glass threads which in turn are composed of a plurality of glass filaments, which glass roving is wound on the spool in successive layers and is of generally hollow cylindrical form. The roving has a free end 5 which can be pulled out so that the thread can be drawn off from the centre, that is, from the interior of the spool. The external surface of the spool is covered with a covering 2 over the whole axial length of the spool. The covering comprises a rectangular sheet of material equal in width to the length of the spool and slightly longer than the circumference of the spool so that when placed round the spool its ends overlap, as shown.

The covering is of polyurethane foam. As described above, the covering, or that surface of the covering which faces the spool, may be of foam rubber, or other elastomeric material which has irregularities or cavities in its surface so that it can penetrate the gaps and spaces in the outer layers of winding of the spool, thereby supporting and holding them.

An open bag 3 of paper or foil is pushed over the covered spool 1 and held in tight contact with the covered spool by two strips of adhesive tape 4 wrapped round it in the circumferential direction. If desired, a paper sleeve, of width the same as the axial length of the spool, can be placed round the covered spool, or a strip of paper can be wound round the spool and fixed with adhesive tape 4.

The material of the covering 2 may be varied to suit the various qualities and dimensions of roving, by varying its wall thickness and surface characteristics.

When using a covering of polyurethane foam, a thickness of 2 to 3 mm is sufficient for a spool of up to 40 kg in weight, while a thickness of 5 mm should be used for a large spool, e.g. of 60 kg, and a thickness of 10 mm for a spool above 150 kg in weight.

The coarser the individual threads of the roving, the rougher and more uneven should be that surface of the covering which is in contact with the roving.

Figures 4 to 6 show a spool 1 having a covering 2 of a coarse-called polyurethane foam, in which the necessary tension is produced directly by wrapping two strips 4 of adhesive tape round the spool under tension.

Each strip 4 must extend around the whole circumference of the spool. However, such application of tension simply by encircling the covering with two strips of adhesive tape is only suitable for relatively thick covering material i.e. if the covering material has a thickness of at least 7 to 8 mm. For a thinner covering material, it is preferable to apply the tension by the means shown in Figures 1 to 3 for example the open bag 3 of paper or foil and the two strips of adhesive tape 4 as described above, in order to avoid damage to the spool.

In all cases, spools which have been provided with a covering in accordance with the invention may in addition be packaged in the usual manner in bags of foil, individual or multiple cardboard packages, or in pallets above one another with the end of one strand knotted to the beginning of another.

Although the invention has been described in detail with reference to glass rovings, it is also applicable to other forms of threads yarns, strands and bundles, whether inorganic or organic.

WHAT WE CLAIM IS:- 1. A hollow cylindrical spool of thread having an outer covering comprising, at least at its surface facing the thread, an elastomeric material having surface irregularities or cavities, which material encloses the outer layer of winding of the spool under tension and penetrates gaps between the threads of said outer layer.

2. A spool according to claim 1 of glass thread.

3. A spool according to claim 1 or claim 2 wherein the material is a plastics foam.

4. A spool according to claim 3 wherein the foam is a coarse-celled polyurethane foam.

5. A spool according to claim 1 or claim 2 wherein the material is foam rubber.

6. A spool according to any preceding claim wherein the covering is a rectangular strip the width of which is the same as the axial length of the spool and the length of which is greater than the circumference of the spool so as to form an overlap.

7. A hollow cylindrical spool of thread constructed and arrange substantially as herein described and shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. Figure 6 is a top plan of the spool of Figure 4. A spool or package 1 (Figs. 1 to 3) comprises a glass roving which in turn comprises a plurality of spun glass threads which in turn are composed of a plurality of glass filaments, which glass roving is wound on the spool in successive layers and is of generally hollow cylindrical form. The roving has a free end 5 which can be pulled out so that the thread can be drawn off from the centre, that is, from the interior of the spool. The external surface of the spool is covered with a covering 2 over the whole axial length of the spool. The covering comprises a rectangular sheet of material equal in width to the length of the spool and slightly longer than the circumference of the spool so that when placed round the spool its ends overlap, as shown. The covering is of polyurethane foam. As described above, the covering, or that surface of the covering which faces the spool, may be of foam rubber, or other elastomeric material which has irregularities or cavities in its surface so that it can penetrate the gaps and spaces in the outer layers of winding of the spool, thereby supporting and holding them. An open bag 3 of paper or foil is pushed over the covered spool 1 and held in tight contact with the covered spool by two strips of adhesive tape 4 wrapped round it in the circumferential direction. If desired, a paper sleeve, of width the same as the axial length of the spool, can be placed round the covered spool, or a strip of paper can be wound round the spool and fixed with adhesive tape 4. The material of the covering 2 may be varied to suit the various qualities and dimensions of roving, by varying its wall thickness and surface characteristics. When using a covering of polyurethane foam, a thickness of 2 to 3 mm is sufficient for a spool of up to 40 kg in weight, while a thickness of 5 mm should be used for a large spool, e.g. of 60 kg, and a thickness of 10 mm for a spool above 150 kg in weight. The coarser the individual threads of the roving, the rougher and more uneven should be that surface of the covering which is in contact with the roving. Figures 4 to 6 show a spool 1 having a covering 2 of a coarse-called polyurethane foam, in which the necessary tension is produced directly by wrapping two strips 4 of adhesive tape round the spool under tension. Each strip 4 must extend around the whole circumference of the spool. However, such application of tension simply by encircling the covering with two strips of adhesive tape is only suitable for relatively thick covering material i.e. if the covering material has a thickness of at least 7 to 8 mm. For a thinner covering material, it is preferable to apply the tension by the means shown in Figures 1 to 3 for example the open bag 3 of paper or foil and the two strips of adhesive tape 4 as described above, in order to avoid damage to the spool. In all cases, spools which have been provided with a covering in accordance with the invention may in addition be packaged in the usual manner in bags of foil, individual or multiple cardboard packages, or in pallets above one another with the end of one strand knotted to the beginning of another. Although the invention has been described in detail with reference to glass rovings, it is also applicable to other forms of threads yarns, strands and bundles, whether inorganic or organic. WHAT WE CLAIM IS:-

1. A hollow cylindrical spool of thread having an outer covering comprising, at least at its surface facing the thread, an elastomeric material having surface irregularities or cavities, which material encloses the outer layer of winding of the spool under tension and penetrates gaps between the threads of said outer layer.

2. A spool according to claim 1 of glass thread.

3. A spool according to claim 1 or claim 2 wherein the material is a plastics foam.

4. A spool according to claim 3 wherein the foam is a coarse-celled polyurethane foam.

5. A spool according to claim 1 or claim 2 wherein the material is foam rubber.

6. A spool according to any preceding claim wherein the covering is a rectangular strip the width of which is the same as the axial length of the spool and the length of which is greater than the circumference of the spool so as to form an overlap.

7. A hollow cylindrical spool of thread constructed and arrange substantially as herein described and shown in the accompanying drawings.