Патент USA US2407355код для вставки
Sept. 1946. a. H. WALTON ETVAL ' 2,497,354 MACHINE FOR COVERING WIRES WITH INSULATING MATERIALS Filed Dec. 24, 1943 '2 Sheets-Sheet 2v CEaRc: H. WALTON, JOSHUA C. Qua YLE 2 Farm Jams - I nventors ‘ MWW, tlorneys- 2,407,354 Patented Sept. 10, 1946 UNITED STATES PATENT OFFICE 2,407,354 MACHINE FOR COVERING WIRES WITH INSULATING MATERIALS George Hall Walton, Helsby, near Warrington, Joshua Creer Quayle, Helsby, and Peter Jones, Kelsail, near Chester, England, assignors to British Insulated Cables Limited, Prescot, Eng land, a British company Application December 24, 1943, Serial No. 515,506 In Great Britain January 1, 1943 8 Claims. (Cl. 154—2.26) 1 In the covering of wires with insulating mate rial by the so-called longitudinal method, two sheets of unvulcanised rubber in the form of long strips are passed longitudinally between a pair of circumferentially grooved rolls With a group of parallel wires between them. The grooves in the rolls register with each other and form at the nip circular apertures or passes through each of which passes a wire with parts of the two sheets of insulating materiah one forming the upper and the other the lower half of the covering of the wire. At each side of each groove the two sheets of rubber are very forcibly compressed so that they are almost severed and seams are formed at each side of the wire betv com the upper sheet and the lower sheet by the forcible com pression of the insulating material there. These machines were developed on the basis of the use of sheets of unvulcanised rubber compound which possess the property of forming a seam under compression at normal atmospheric temperatures. In the invention set out in the application for Letters Patent No. 472,338 the longitudinal ma chine is adapted for use with other materials, for instance, plasticised polyvinyl compositions which 2 about to enter the nip, heating by a high fre quency electric ?eld is effected by feeding high frequency current to the wires in such a way as to establish a field in the insulating material when it comes close to and in contact with these wires. In doing this advantage is taken of the resonant e?ect of an insulated line for the purpose of producing a rise of voltage between the point of feeding the wires and the point at which the 10 high frequency heating has to become e?ective. This rise of voltage is, as is well-known, dependent upon the distance between the point of feeding the line and the point of terminating it and on the nature of the termination. The best distance is 15 in the neighbourhood of a quarter of the wave length corresponding to the high frequency volt age applied. Since the termination in this case will have the character of capactitative reactance combined with resistance, the distance between 20 the point of feeding and the point of terminating will ‘be somewhat less than a quarter wave length and can be found readily by experiment. Since it is contemplated that for this heating a frequency of the order of 20 million cycles per 25 second and upwards will be used, it will be seen that the length in question is not an inconvenient require to be at a temperature substantially above one. normal atmospheric temperature in order that Three embodiments of the invention are indi satisfactory seams can be made by compression cated in the accompanying diagrammatic draw between the rolls. In that improved machine the heating of the 30 mgs. In Figure l, which is a side elevation, an ar sheets of insulating material is effected by passing rangement is indicated such as described in the each sheet by itself, or with the other sheet, said specification for heating the two sheets of through heating means, as the sheets are ap insulating material by high frequency electric proaching the grooved nipping rolis. The pre ferred means of heating is by the utilisation of the 35 fields as they are approaching the rolls and the present invention is shown as an additional heat~ effect of a high frequency alternating or ?uctuat ing means in such a machine. In the other lig ing ?eld, through which the material passes as it ures the apparatus for heating the sheets of mate is approaching the rolls and arrangements are rial as they approach the rolls is not shown, only mentioned in which electrodes are arranged near the path of the sheets, or each sheet of material, 40 those parts being indicated which represent the so that as the material moves past these elec present invention. Figure 2 is a plan view corresponding to Figure trodes it is subjected to a, high frequency electric 1. ?eld, either between a pair of electrodes or be Figure 3 is a side elevation of another arrange tween the wires and an electrode. It is also mentioned in the said speci?ca 45 ment and Figure 4 is the corresponding plan view. A third arrangement is shown in Figure 5 in tion that it may be advantageous to supplement side elevation and in Figure 6 this is shown in this heating by some localised treatment of the plan view. ~ sheets as they approach the nip. The present The sheets of insulating material i and 2, as invention makes an addition to or modi?cation‘of the machine described in the said speci?cation by 50 shown in Figure 1, approach the grooved rolls 3 by paths which lead each of them between the two which heating is provided in the immediate electrodes of a high frequency electric ?eld sys neighbourhood of the nip with very simple tem. These consist of a lower electrode formed changes in the apparatus. In accordance with the invention, in a machine in which the two sheets of material are kept apart until they are of a metal band 4, passing round a pair of rollers 5, and- an upper electrode which is a stationary 2,407,354: 3 plate 6. The moving band 4 facilitates the travel of the sheet of material which rests on it and which moves without touching the stationary 4 two small capacities in series at the rolls, each of these capacities being formed by a group of wires l’, the dielectric consisting of the sheets of ma electrode 6. The moving band is at ground po tential and the stationary electrode receives the high potential. From the left-hand ends of the terial i and 2 and the second electrode pro vided by the rolls 3. Into this line is fed high frequency current by means of the coupling loop bands ‘4 the two sheets of material move respec ll placed near the voltage nodal point 9 and tively downward and upward and come together connected with the oscillator [9. at the nip of the rolls 3, resting against these The arrangement shown in Figures 3 and 4 is rolls during the last part of the movement. In 10 similar in principle to that just described, but the space between the two sets of electrodes 4 and provides a better utilisation of the width of the 6 run horizontally a set of parallel wires ‘i which rolls 3 since it is unnecessary here to provide a are aligned with the grooves in the rolls 3 so that clear space between the two sets of wires 1 at each wire when passing through the nip of the the rolls At this end of the line the wires rolls lies within a groove and is enclosed between 15 approach together as shown clearly in. Figure 4. portions of the two sheets of insulating material They are separated into two sets by guides l2 I and 2. This material, which may, for instance, and it. Each of the guides i2 is a block of in be a plasticised polyvinyl compound, requires to sulating material, standing vertically, with holes be heated sufficiently to become soft and ad for the wires arranged in a vertical line. The hesive so that by the compression of the parts of guide members l3 are vertical bars of conduct the rolls between the grooves the material is made ing material which are both grounded and there to ?OW laterally into the grooves and is caused by conn ected together and form, not only a guide, to make a seam at each side so that it proceeds but a short-circuiting connection at the nodal beyond the rolis as a tube 8 enclosing a wire, the point. By this arrangement of guides and by several tubes being connected only by very thin appropriate means for leading the wires from the webs of material so that the covered wires can be supply bobbins to the guides I3, the wires are easily separated from each other. divided into two vertical sets until they reach To ensure that the two sheets of material the guides i2 from which point they begin to shall be at the right temperature at the moment turn into a single horizontal plane which they of coming into contact in the nip of the rolls 3, _ reach at the nip of the rolls 3. The feeding heating localised in that region is provided in in this case is also done by means of a loop ll accordance with the present invention by setting receiving high frequency current from an oscil up a strong high frequency electric field between lator (not shown). the wires l and the rolls 3. This ?eld passes In the arrangement shown in Figures 5 and 6', through the sheets of insulating material I and the wires ‘i are used in a single set as one side 2 and generates heat therein by dielectric loss, of the line, the other side being provided by the heating being most intense in the direct a strip M of metal arranged below the wires 1 neighborhood of each wire. and connected at the right-hand end to the The present invention provides for obtaining short circuiting bar l5 which is grounded and the necessary high voltage between wires '1 and locates the nodal point. At the left-hand end rolls 3 in a most convenient manner. It takes the strip It makes contact with one of the rolls advantage of the well-known fact that a con 3 by means of brushes It. The two rolls are ductor in a resonant line having a length ap» connected together electrically by their hous proximately equal to one-quarter wave length corresponding to the frequency of a high fre ing. In this case the housing and the rolls are insulated from ground, as indicated diagram quency electric supply system will have on it a matically by the insulated platform I‘! shown standing wave» of electric potential and another in Figure 5. The feed to the line could in this inversely disposed standing wave of electric cur also be by way of a loop placed between rent so that it can be fed at the low potential the wires 1 and the strip [4, but an alternative end with a substantial current and will exhibit 50 arrangement is shown in which the feed is by a at the other end a high potential difference conductive connection from the oscillator l9 by and a small or zero current. The wires 1 of the present case are made to serve as such a line, way of the short circuiting bar 15 and another the feeding end being that remote from the rolls so that the high potential end is at the rolls. Three systems by which this is carried out are shown in the drawings. In each of them the dimension which approximates to one-quarter wave length is indicated by L. The feeding end is near the right-hand end of this length in each case so that the high. potential end is at the insulated from ground. left-hand where the rolls are situated. . In the arrangements shown in Figures 1 and 2 two sides of a line are provided by two groups of wires ‘i which are spaced apart laterally. The nodal point, i. e., the voltage minimum point, is located by the grounded short~circuiting bar 9 across and in contact with which all the wires 1 bar I8 placed a short distance away from it and The arrangement shown in Figures 5 and 6 has a combination of advantages of simplicity, con venience and efficiency. but other dispositions of the parts of the machine are possible using the wires in one set as one side of the line. The arrangement shown in Figures 5 and 6 also has the advantage that the high frequency ?elds are mainly located in the space between the wires and the strip l4 so that losses in the surrounding bodies are small. It will be seen that the additional heating means provided by the present invention can very conveniently be applied to the wires as they are led into the machine and thereby heat can run. Near the rolls 3 the wires are supported be generated in the insulating material at the on an insulating bar iii. This is provided solely 70 point where the highest temperature of this ma for the. purpose of raising the level of they wires terial is required and this is done in a way which. slightly. for convenience in the disposition of the apparatus. The arrangement described pro vides a quarter-wave length line short circuited at the voltage nodal point and connected through facilitates the disposition of the high voltage part of the apparatus. What we claim as our invention is: 1. Apparatus for heating pairs of strips of or 2,407,354 5 6 wires of one group lying in one plane and the ganic resin insulation by dielectric loss as they wires of the other group lying in another plane enter the nip of a pair of cooperating electrical parallel therewith, and means located near to ly conducting rolls having a plurality of opposed the rolls for bringing all the wires into one plane. grooves therein, each pair of grooves de?ning a 5. The apparatus de?ned by claim 1 having pass for continuously applying said strips as a one side of the said line constituted by all of the coating to an electrically conducting wire trav said wires in parallel and the other side by an elling through said pass and seaming together electrically conductive member extending along the strips applied to each wire, said apparatus side said wires between the said connecting means comprising a capacitor formed by the insulation strips together with the rolls and the portions 10 and the rolls, and means for coupling said mem her at one end thereof to the said connecting of the wires in the nip thereof, a resonant trans means and at the other end thereof to the rolls. mission line having two parallel sides so connect» 6. The apparatus de?ned by claim 1 having ed to said capacitor as to apply high-frequency the said feeding means coupled to the line in the voltage thereto, at least one side of said line con sisting of a length of at least one of said wires 15 part thereof directly adjacent to the said point whereby to obtain a large rise in voltage between on the entering side of said rolls and conductive said feeding means and the two sides of the line 1y related to the portion of said one of said wires at the rolls. in the/nip of the rolls, means electrically con 7. The apparatus de?ned by claim 1 having necting the two sides of the line together at a said feeding means constituted by a coupling loop point in said length distant from said rolls by nearly one quarter of the Wave-length corre sponding to said frequency, and means between said point and the rolls for feeding said high frequency electric energy into said line. 2. The apparatus de?ned by claim 1 having the two sides of the said line constituted by two spacially separated groups of the said wires. 3. The apparatus de?ned by claim 1 having the two sides of the said line constituted by two spacially separated groups of the said wires all lying in one and the same plane. 4. The apparatus de?ned by claim 1 having the two sides of the said line constituted by two spacially separated groups of the said Wires, the adjacent the line and the said point and an os cillator electrically connected to said loop. 8. The apparatus de?ned by claim 1 having said. feeding means constituted by an oscillator, an electrically conductive connection from said oscillator to the line at said point and another electrically conductive connection from said os oillator to a point in one side of said line located a distance from said point which is only a minor proportion of the length from said point to the rolls. GEORGE HALL WALTON. JOSHUA CREER QUAYLE. PETER JONES.