CONICAL COILING OF WIRE ON A SPOOL WITH AT LEAST ONE CONICALLY FORMED FLANGE

Abstract: The invention relates to a method, whereby wire is coil­ ed conically on a spool, which is provided with at least one conically formed flange and whereby during the whole coil­ ing operation, the number of windings per layer is gradually increased.

Description: This invention relates to a method of conical coiling wire on a spool having a core and two flanges at the opposite ends thereof, whereby the wire is wound in successive layers between the two flanges and whereby each layer comprises a number of successive windings, the wire is wound on the core in a special way thereby forming a conical section on the core between the two flanges. Such a method of conical coiling wire on a spool is known from the U.S.A. patent No. 3.218.004. This U.S.A. patent 3.218.004 learns a method for forming a tapered or conical coil on a core of a spool between the two flanges of the spool. In this U.S.A. patent 3.218.004, all the successive windings of each layer are distributed over the whole distance between the two flanges and the winding speed is changed by a motor so that the wire build-up is greater at the bottom than at the top of the spool and a conical coil is formed. A disadvantage of this known method according to this U.S.A. patent 3.218.004 is that the distance between each pair of successive windings of a layer is changing so that many windings of such a layer do not support each other, particularly at the top of the spool. Another disadvantage is that the successive layers do not support each other, so that there is a great danger that when the spool is positioned vertically, the windings of one layer are sliding down the core, which leads to tangling of the wire. The object of the present invention is to provide a method, whereby the above-mentioned disadvantages are eliminated. To obtain this object, the invention provides for the method according to this U.S.A. patent No. 3.218.004 or as described above, that the wire is coiled conically on the spool provided with at least one conical flange by starting with a first layer with a minimum number of windings, whereby the number of windings per layer is gradually increased throughout the whole coiling operation and whereby the amount of the increase in the number of windings in each successive layer, after the completion of a first conical section extending over the whole length of the core, is determined as a function of the conicity of the conical flange. A great advantage of this method according to the invention is that all the successive windings in each layer, as well as all the successive layers support each other or it means that a very stable coil is obtained, so that there is no danger, when the spool is positioned vertically, that the windings of a layer will slide down the core of the spool. A further advantage is that during the coiling operation by using such a spool with at least one conical flange, a substantially greater volume of wire can be wound on this same spool, which obviously leads to an important saving in the number of spools required. Another advantage of the method according to this invention is, that during the uncoiling operation over such a conical flange, the windings are subjected to smaller tensions and friction, which avoid possible wire ruptures. The invention also relates to a method, which is characterized in that the wire is coiled conically on a spool with two conical flanges. The EP-A-0109539 document already learns the use of a spool with conical flanges for facilitating the unwinding operation. The invention will now be illustrated with reference to the drawing, wherein : figure 1 shows a cross-section of a spool consisting of a cylindrical core, a straight lower flange and a conical upper flange wiht conically coiled wire, figure 2 shows a cross-section of a spool consisting of a slightly conical core, a conical lower flange and a conical upper flange with conically coiled wire on this spool. Figure 1 shows a spool 7 with a cylindrical core 8 provided with a straight lower flange 9 and with a conically tapered upper flange 10 or with at least one conical flange. The upper flange 10 has a wire receiving surface extending frusto-conically from the core 8. The axis 13 of the cylindrical part 8 and the axis 12 of the conical upper flange 10 coincide. In conical coiling according to the invention, a first portion of length of wire is coiled around the core to form a conical section 11. Therefore, coiling commences or starts at this straight lower flange and a first layer comprising a minimum number of windings, for example one winding, will be formed, after which, or if desired after a brief continuation of the coiling operation at increased pitch or not, in the upward direction ; the direction of layer formation is reversed, so that a second layer is then formed in the direction of the lower flange. When this second layer reaches the lower flange, the direction of layer formation is again reversed and coiling continues to form a third layer until the last convolution or winding of the third layer is wound directly on to the cylinder core, after which, or if desired after a brief continuation of coiling at increased pitch, the direction of layer formation is again reversed, etc. Coiling in this manner is continued until a first conical section 11 has been formed, whereby the outer boundary of which is constituted by the layer of windings which extends from the intersection between the cylindrical core and the conical upper flange to the point at which the last convolution at the other extremity of the same layer meets the lower flange. The greatest thickness 6 of the first conical section is important in the determination of the dimension of the lower flange 9 with respect to the dimension of the upper flange 10. The outside diameter of the two flanges differs by an amount equal to at least twice the dimension of the said part 6 of the first conical section. After the completion of the said first conical section 11, whereby each successive layer comprises a greater number of windings than the previous layer ; the winding operation is continued, whereby the increase in the number of convolutions or windings per layer from the point at which the conical upper flange 10 has been reached, is determined primarily by the concicity of the upper flange 10 used. As a general rule, the increase in the number of windings between two successive layers after the point at which the conical upper flange 10 has been reached, will be relatively small ; and mostly smaller than the increase in the number of windings between two successive layers during the formation of the first conical section 11. Figure 2 shows a spool 14 with a slightly conically formed core 15 provided with a less conically formed lower flange 16 and with a more conically formed upper flange 17 or this spool 14 is provided with two flanges 16, 17 having a wire receiving surface extending frustoconically from the core 15. The axis 18 of the core 15 and the axis 19, respectively the axis 20 of the lower flange 16, respectively the upper flange 17 coincide. After the completion of the first conical section 11, whereby each successive layer comprises a greater number of windings than the previous layer ; the coiling operation is continued, whereby the increase in the number of windings per layer from the point at which the conical upper flange 17 has been reached, is determined by the conicity of the upper flange 17 and the lower flange 16. It is clear that in the method described in figure 1, whereby a spool 7 with a cylindrical core 8 and with at least one conical flange is used ; it is also possible to use a spool 7 with a slightly tapered or slightly conical core 8. It is also possible to use in the method described in figure 2, a cylindrical core 15 instead of a slightly tapered core 15.

Claims: Method of conical coiling wire on a spool (7) having a core (8) and two flanges (9, 10) at the opposite ends thereof, whereby the wire is wound in successive layers between the two flanges (9, 10) and whereby each layer comprises a number of successive windings, the wire is wound on the core (8) in a special way thereby forming a conical section (11) on the core (8) between the two flanges 9, 10), characterized in that the wire is coiled conically on the spool (7) provided with at least one conical flange (10) by starting with a first layer with a minimum number of windings, whereby the number of windings per layer is gradually increased throughout the whole coiling operation and whereby the amount of the increase in the number of windings in each successive layer, after the completion of a first conical section (11) extending over the whole length of the core, is determined as a function of the conicity of the conical flange (10). Method according to claim 1, characterized in that the wire is coiled conically on a spool (14) provided with two conical flanges (16, 17).

Inventors: ANSEEL, FREDDY, COSAERT, PIERRE
Applicants: N.V. BEKAERT S.A.
Application year: 1987
Main classification: B65H55
IPC codes: H01F41, B65H49, B65H54, B65H55, B65H75