CH94758A

CH94758A - Insulating tube for telephone plugs and for similar electrical connection parts of electrical appliances, and method of manufacture.

Info

Publication number: CH94758A
Authority: CH
Inventors: Company Bell Tel Manufacturing
Original assignee: Bell Telephone Mfg
Priority date: 1920-11-22
Filing date: 1920-11-22
Publication date: 1922-05-16

Description

Tube isolant pour fiches telephoniques et pour pieces analogues de connegion electrique d'appareils electriques, et procede de fabrication. Afin de proteger los Parties libres des fiches telephoniques ou des pieces analogues de connexion electrique de certains appareils electriques, an utilise des tubes isolants les- quels ont ete construits, jusqu'ä ce jour en fibre. L'emploi de res tubes West cependant pas sans offrir de serieux inconvenients par Suite du fait quo los matieres fibreuses obte- nues par ]es procedes actuels de fabrication, contiennent des traces de sel de zinc amenant la corrosion des Parties metalliques adjacentes. Ce phenomene se presente surtout quand 1e tube isolant se trouve dans un endroit hu mide. Cette corrosion West pas seulement due d faction chimique des sels presents, mais provient aussi des reactions eleetro-chimiques resultant de la difference de potentiel qui se cree entre certaines Parties metalliques de l.'appareil, quand du courant passe b, travers celui-ci, et 1e zinc du tobe. Des recherches tres serieuses ont ete faites pour eliminer cet inconvenient, mais aucun moyen satisfaisant, permettant d'eviter faction perturbatrice des sels presents, n'a ete trouv6. L'enlevement de toute trace d'humidite et fapplication dune coache de substance protectrice quel- conque Sur la fibre n 'ont pas amene 1e re- sultat voulu. Au contraire rette coache pro- tectrice rend la fibre excessivement cassante et ne peut pas eire employee Jans los condi- tions ordinaires de fonctionnement. Insulating tube for telephone plugs and for similar electrical connection parts of electrical appliances, and method of manufacture. In order to protect the free parts of telephone plugs or similar electrical connection parts of certain electrical appliances, insulating tubes are used, which have until now been made of fibre. The use of res tubes, however, is not without offering serious drawbacks due to the fact that the fibrous materials obtained by] current manufacturing processes contain traces of zinc salt causing corrosion of the adjacent metal parts. This phenomenon occurs especially when the insulating tube is in a damp place. This corrosion is not only due to the chemical action of the salts present, but also comes from the electro-chemical reactions resulting from the difference in potential which is created between certain metal parts of the device, when current passes through it. , and tobe zinc. Very serious research has been done to eliminate this drawback, but no satisfactory means has been found to avoid the disturbing action of the salts present. Removing all traces of moisture and applying a coating of protective substance of any kind to the fiber did not bring the desired result. On the contrary, this protective layer makes the fiber excessively brittle and cannot be used under ordinary operating conditions.

La presente invention se rapporte ä, un tobe isolant pour fiches telephoniques et pour pieces analogues de connexion electrique d'ap- pareils electriques, lequel est forme Tun tube metallique recouvert interieurement et exte- rieurement d'au moins une coache de matiere isolante. Un procede permettant la fabrication de ce tube conaiste ä enrouler d'abord une matiere impregnee dune substance isolante autour d'un dispositif dont 1e diametre peut eire change, puis ä glisser 1e tube metallique Sur rette matiere isolante, pour enfin recou vrir ce tube metallique exterieurement dune nouvelle coache de la matiere impregnee, 1e tout etant alors place dann un moule oix 1e diametre du dispositif envisage est modifie. The present invention relates to an insulating tube for telephone plugs and for similar electrical connection parts of electrical apparatus, which is formed of a metal tube covered internally and externally with at least one layer of insulating material. A process allowing the manufacture of this tube consists of first rolling up a material impregnated with an insulating substance around a device whose diameter can be changed, then sliding the metal tube over another insulating material, to finally cover this metal tube. externally with a new coach of the impregnated material, the whole being then placed in a mold where the first diameter of the device envisaged is modified.

Le dessin ei-joint montre ä titre d'exem- ple une des formes de realisation de fobjet et du procede de 'la pAsente invention. La fig. 1 montre un mandrin expansible sur le- quel est enroulee la preiniere coache de ma- tiere isolante. La fig. 2 montre 1e tube me- tallique entourarit la Premiere coache de matiere isolante placee sur 1e mandrin, une seconde coache de la meme matiere isolairte etant enroulee exterieurement au tobe m6tal- lique. La fig. 3 Bonne une vue de 1'ensemble forme par 1e tube metallique et les deux Couches de inatiere isolante place dann uni appareil de compression. La fig. 4 dorine une coupe transversale de cet ensemble. La fig. 5 indique 1e procede suivi pour effectuer la compression ptiis 1e sechage de la matiere isolante. La fig. 6 Bonne une vue d'un tobe isolant fini, pret ä etre utilise. La fig. 7 montre 1e tube isolant, obtenu par 1e procede decrit ici, applique ä une fiche telephonique. The accompanying drawing shows by way of example one of the embodiments of the object and of the method of the present invention. fig. 1 shows an expanding mandrel on which is wound the first coach of insulating material. fig. 2 shows the metal tube surrounded the first coach of insulating material placed on the mandrel, a second coach of the same insulating material being wound outside the metal tube. fig. 3 Good view of the assembly formed by the first metal tube and the two layers of insulating material placed in a compression device. fig. 4 shows a cross section of this assembly. fig. 5 shows the process followed to effect compression and drying of the insulating material. fig. 6 Good view of a finished insulating tube, ready for use. fig. 7 shows the insulating tube, obtained by the process described here, applied to a telephone plug.

0n a trouve qu'un tobe nietallique dort les surfaces interieure et exterieure sont iso- lees, constitue un tube isolant libre des in- conv6riients mentionnes precedeminent. La substance isolante servant ä recouvrir 1e metal peut etre une matiere fibreuse teile que du Papier, de la toile, ou tout autre produit convenable, suffisamment impregne d'un liquide de preference ä Base dune subs- tance resineuse naturelle ou synthetique. Des produits de condensation du Phenol, eomme par exemple la balielite, 1e redinanol . et 1e condensite, aussi bien que d'autres Corps or- ganiques pouvant fournir un produit resistant ,de structure homogene, peuvent etre utilises dans ce bat. Certaines matieres adhesives, telles que caskne, colle forte ou autres subs- tance glutineuses, peuverit aussi trouver ici leur emploi. Enfin an peut utiliser, pour 1e bat poursuivi, du Papier presentarit une epais- seur d'environ 0,2 min impregne d'un enduit ,de Phenol. Une methode suivant laquelle Ces Couches isolantes peuvent eire appliquees sui- 1e tube est facilement comprise par la des- cription suivarite. It has been found that a metal tube, where the inner and outer surfaces are insulated, provides an insulating tube free of the drawbacks mentioned above. The insulating substance used to cover the metal can be a fibrous material such as paper, canvas, or any other suitable product, sufficiently impregnated with a liquid, preferably based on a natural or synthetic resinous substance. Phenol condensation products, such as, for example, balielite, redinanol. and condensate, as well as other organic bodies which can provide a strong product of homogeneous structure, can be used in this task. Certain adhesive materials, such as caskne, strong glue or other glutinous substances, can also find their use here. Finally, one can use, for the continued beat, Paper presenting a thickness of about 0.2 min impregnated with a coating of Phenol. One method by which these insulating layers can be applied to the tube is readily understood from the following description.

D'apres la fig. 1, les deux Parties du man drin expansible 1, de preference en acier, sont assemblees et maintemies par 1e collier 2. Une coache de inatiere isolante 3, teile que du Papier impregne dune substance plas- tique derivant du Phenol, est ensuite enroulee sur 1e mandrin jusqu'ä, ce que 1'epaisseur ne- cessaire ä 1'isolation soit obtenue. Le tube metallique qui doit fournir la resistance vou- lue < L 1'objet termine, est glisse sur la coache de Papier enveloppant 1e mandrin, ce tube RTI ID="0002.0276" WI="8"HE="4" LX="1259" LY="472"> etant designe par 1e Chiffre 4 sur la fig. 2. De preference, les extreinites du tobe nietal- lique sont arrondier et res surfaces interieure et exterieure sont rendues rugueuses au moy en d'un jet de sable. La longueur de la coache de Papier enroulee sur 1e mandrin doit etre teile quelle depasse les deux extremites du tobe metallique quand celui-ci occupe la Po sition voulue. Sur 1e tube metallique mir ei) place, est etisuite enroulee une ou plusieurs autres couches5 de Papier impregne. Lette enveloppe est aussi legerement plus longue que Je tube metallique de maniere i, pouvoir etre i-epliee aux deux extremites. L'ensemble ainsi obtenu est alors plaee Jans un moule 6 represente sur la fig. 3. Ce moule est cons- truit de maniere h etre exactement conforme au Profil et aux dimensions que doit presenter 1'objet fini. Les extremites de 1'interieur du moule sont taillees en biseau afin de Bonner la forme voulue au Papier impregne depassant de Part et d'autre 1e tube metallique. La car- casse en fer 7 est alors placee de maniere ä entourer 1e moule, et la vis 8 est serree. La cle 9 est enfin introduite ä l'interieur du mandrin, et Von peut voir par la fig. 4 don- nant une coupe transversale de 1'ensemble des pieces, la Position des differents elements. Dans cette figure, 1 indique 1e niandrin, 3 est la Premiere coache de Papier impregne, 4 est 1e tube metallique, 5 est la deuxieme coache de Papier impregrie, et 9 est la cle introduite < i 1'interieur du mandrin. En imprimant ä cette cle un mouvement de rotation an comprime contre la surface interieure du tube metalli- que la Premiere coache de Papier. Lette nou- velle Position de la cle est montree sur , la fig. 5. Afin de secher 1e inilieu impregne et afin de 1e faire adherer fermement au tube metallique, 1'ensemble est soumis ä une tem- perature determinee. D'apres la fig. 5 ce re- sultat est obtenu au moyen dune etuve chauffee electriquement. Apres que Pensemble a dte soumis ä, la chaleur un temps suffisam- ment long, 1e moule est retire de 1'etuve et refroidi. Lobjet ainsi termine se presente alors sous la forme irrdiquee dass la fig. 6. La fig. 7 montre un tube metallique isolant semblable !i. celui qui vient d'etre obtenu, applique au cas dune fiche tdlephonique, 1e bat etant ici de proteger les contacts et les oonnexions dlectriques placees ä l'interieur de cette flehe. According to fig. 1, the two Parts of the expandable mandrel 1, preferably made of steel, are assembled and maintained by the collar 2. A coach of insulating material 3, such as Paper impregnated with a plastic substance derived from Phenol, is then wound on the mandrel until the necessary thickness for the insulation is obtained. The metal tube which must provide the desired resistance to the finished object is slid over the Paper coach wrapping the mandrel, this tube RTI ID="0002.0276" WI="8" HE="4" LX=" 1259" LY="472"> being designated by the first number 4 in fig. 2. Preferably, the ends of the metallic tube are rounded and the interior and exterior surfaces are roughened by means of a sandblast. The length of the Paper Coil wound on the mandrel must be such that it exceeds the two ends of the metal tube when the latter occupies the desired position. On the placed metal tube, one or more other layers5 of impregnated paper are then rolled up. The casing is also slightly longer than the metal tube so that it can be folded at both ends. The assembly thus obtained is then placed in a mold 6 shown in FIG. 3. This mold is constructed in such a way as to conform exactly to the Profile and to the dimensions that the finished object must have. The extremities of the interior of the mold are bevelled in order to give the desired shape to the impregnated paper protruding from both sides of the metal tube. The iron frame 7 is then placed so as to surround the mold, and the screw 8 is tightened. The key 9 is finally introduced inside the chuck, and it can be seen from fig. 4 giving a cross section of all the parts, the position of the various elements. In this figure, 1 indicates the chuck, 3 is the first impregnated paper coach, 4 is the metal tube, 5 is the second impregnated paper coach, and 9 is the key inserted inside the chuck. By imparting to this key a rotational movement, it compresses against the inner surface of the metal tube the First Paper Coach. The new position of the key is shown in , fig. 5. In order to dry the impregnated medium and to make it adhere firmly to the metal tube, the assembly is subjected to a determined temperature. According to fig. 5 this result is obtained by means of an electrically heated oven. After the assembly has been subjected to the heat for a sufficiently long time, the mold is removed from the oven and cooled. The object thus finished then appears in the irregular form in fig. 6. Fig. 7 shows a similar insulating metal tube!i. that which has just been obtained, applies to the case of a telephone plug, the first battle here being to protect the contacts and the electrical connections placed inside this arrow.

Au lieu du mandrin expansible utilise ici, d'autres dispositifs, permettant de comprimer la Premiere coache de Papier contre la sur- face interieure du tube rnetallique, peuverrt etre employes. D'autre pari le dispositif exer- cant la Pression voulue sur 1e moule peut faire Partie de Pdtuve, de maniere qu'aucune perte de chaleur n'ait lieu par suite du re- froidissement de la carcasse en fer i chaque fois que 1e moule est retire de Petuve. Si 1'on emploie un moule dont les diverses Par ties constitutives sollt disposees de maniere ä s'adapter Pulle ä, Pautre tres intimement, les dispositifs separes de serrage, representes en 7 et 8 sur les fig. 3 et 5, peuvent etre omis. Enfin si au lieu du Papier utilise dann 1'exemple decrit, an ernploie dans la formation du tube une matiere adhesive ou glutineuse irnpregnee dune substance isolante, 1'op6ra- tion de sechage peut etre supprimee. Instead of the expandable mandrel used herein, other devices which compress the First Paper Coach against the inner surface of the metal tube may be employed. On the other hand, the device exerting the desired pressure on the mold can be part of the oven, so that no loss of heat takes place as a result of the cooling of the iron carcass each time the mold is is removed from Petuve. If a mold is used, the various constituent parts of which are arranged so as to adapt to each other very closely, the separate clamping devices, shown at 7 and 8 in FIGS. 3 and 5, can be omitted. Finally, if instead of the paper used in the example described, an adhesive or glutinous material impregnated with an insulating substance is employed in the formation of the tube, the drying operation can be dispensed with.

0n voit que les choes que 1e tube pour- rait recevoir Pendant sa manipulation, ou Pusure qui resulte de soll service, ne peuvent produire d'avaries aux conducteurs electriques places ä 1'interieur. De plus, 1'enveloppe@obte- nue ne peut se corroder, et forme un ensemble parfaitement isolant, evitant tout danger de courts-circuits. Des essais faits au moyen de fiches electriques utilisant des tubes sembla- bles ont demontre leur superiorite absolue sur les fiches utilisant des tubes formes de fibres, tels qu'ils ont dtd construits jusqu'ä ce jour. It is seen that the shocks that the tube could receive during its handling, or the wear which results from its service, cannot produce damage to the electrical conductors placed inside. In addition, the obtained envelope cannot corrode, and forms a perfectly insulating assembly, avoiding any danger of short circuits. Tests made with electrical plugs using similar tubes have shown their absolute superiority over plugs using fiber tubes as hitherto constructed.

Claims

CLAIMS I Insulating tab for telephone plugs and for similar electrical connection parts for electriqrres apparatus, characterized in that it is formed of a metal tab covered internally and externally with at least one coach of insulating material. II Method of manufacturing an insulating tube according to claim I, characterized in that a material impregnated with an insulating substance is first wound around a device whose diameter can be changed, then a metal tube is slides on this insulating material, which metal tube is finally covered with a new coach of the insulating material, the first while then placed in a mold where the first diameter of the device envisaged is modified. SUB-CLAIMS 1 Insulating tube according to claim 1, characterized in that the insulating layers covering the metal tube are impregnated with a plastic substance derived from phenol.

2 Insulating tube, conforming to ä. claim 1 and sub-claim 1, characterized in that the insulating layers are formed of a fibrous material impregnated with said plastic substance.

3 Insulating tube, according to claim 1 and 5, sub-claim 1, characterized in that the insulating layers are formed from an adhesive material impregnated with said plastic substance.

4 Manufacturing process, in accordance with claim II, characterized in that the material used impregnated with an insulating substance is a fibrous material and in that the assembly obtained by the metal tube and the internal and external layers of the said material, is finally subjected to the action of heat.