CH396536A - Plastic welding socket and process for their manufacture - Google Patents

Plastic welding socket and process for their manufacture

Info

Publication number
CH396536A
CH396536A CH1272262A CH1272262A CH396536A CH 396536 A CH396536 A CH 396536A CH 1272262 A CH1272262 A CH 1272262A CH 1272262 A CH1272262 A CH 1272262A CH 396536 A CH396536 A CH 396536A
Authority
CH
Switzerland
Prior art keywords
sleeve
welding
socket
heating wire
embedded
Prior art date
Application number
CH1272262A
Other languages
German (de)
Inventor
Ernst Dipl Ing Rueede
Original Assignee
Rollmaplast Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rollmaplast Ag filed Critical Rollmaplast Ag
Priority to CH1272262A priority Critical patent/CH396536A/en
Priority to DE19631554861 priority patent/DE1554861B1/en
Priority to AT837563A priority patent/AT257146B/en
Publication of CH396536A publication Critical patent/CH396536A/en

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D23/00Producing tubular articles
    • B29D23/001Pipes; Pipe joints
    • B29D23/003Pipe joints, e.g. straight joints
    • B29D23/005Pipe joints, e.g. straight joints provided with electrical wiring
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/342Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/342Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding
    • B29C65/3432Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding comprising several wires, e.g. in the form of several independent windings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3468Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special electrical connectors of windings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3476Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being metallic
    • B29C65/348Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being metallic with a polymer coating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112Single lapped joints
    • B29C66/1122Single lap to lap joints, i.e. overlap joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5221Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5224Joining tubular articles for forming fork-shaped connections, e.g. for making Y-shaped pieces
    • B29C66/52241Joining tubular articles for forming fork-shaped connections, e.g. for making Y-shaped pieces with two right angles, e.g. for making T-shaped pieces
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5229Joining tubular articles involving the use of a socket
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5229Joining tubular articles involving the use of a socket
    • B29C66/52291Joining tubular articles involving the use of a socket said socket comprising a stop
    • B29C66/52292Joining tubular articles involving the use of a socket said socket comprising a stop said stop being internal
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5229Joining tubular articles involving the use of a socket
    • B29C66/52296Joining tubular articles involving the use of a socket said socket comprising sealing elements, e.g. gaskets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/522Joining tubular articles
    • B29C66/5229Joining tubular articles involving the use of a socket
    • B29C66/52298Joining tubular articles involving the use of a socket said socket being composed by several elements
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L47/00Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
    • F16L47/02Welded joints; Adhesive joints
    • F16L47/03Welded joints with an electrical resistance incorporated in the joint

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Branch Pipes, Bends, And The Like (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)

Description

       

  
 



     Kunststoff-Schweissmuffe    und Verfahren zu ihrer Herstellung
Die Erfindung betrifft ein Verfahren zur Herstellung einer Kunststoff-Schweissmuffe zum Verbinden von Rohrleitungselementen aus thermoplastischem Kunststoff unter Verwendung von Heizdraht windungen, welche in die Schweissmuffe eingebettet sind, beim Schweissprozess an eine elektrische Stromquelle angeschlossen werden und nach dem Schweissvorgang im Innern der Verbindungsstelle verbleiben.



   Ferner betrifft die Erfindung eine Schweissmuffe, welche nach dem erwähnten Verfahren hergestellt ist.



   Bei der Verschweissung derartiger Muffen wurde bisher die Schweissspannung in der Regel, zwecks Vermeidung umfangreicher elektrischer Sicherheitsmassnahmen, auf höchstens 50 V beschränkt.   Nach-    teilig ist dabei die Notwendigkeit eines verhältnismässig schweren Transformators, welchem die Aufgabe zufällt, die übliche Netzspannung herunterzutransformieren. Schwere Schweissgeräte bilden nämlich ein ernsthaftes Hindernis für die allgemeine Anwendung dieses Schweissverfahrens auf Bauplätzen usw. Durch Weglassen des Transformators kann das Gewicht der Heizstrom-Regelgeräte wesentlich reduziert werden. Die direkte Entnahme des elektrischen Stromes für den Schweissprozess aus dem Leitungsnetz führt aber zu erhöhten Schweissspannungen.

   Diese bergen Unfallrisiken in sich und beeinträchtigen die Funktionssicherheit von Schweissmuffen üblicher Bauart, indem die Gefahr von Kurzschlüssen zwischen benachbarten Drahtwindungen wächst. Geringfügige Verschiebungen der nackten Drahtwindungen während der Muffenherstellung, beispielsweise im Verlauf des Spritzvorganges oder während des Schweissprozesses, können bei der zur Anwendung gelangenden erhöhten Spannung zu Kurzschlüssen führen. Speziell gross ist diese Gefahr bei der üblichen bifilaren Wicklungsart, bei der die ganze Spannungsdifferenz zwischen zwei benachbarten Leitern auftritt.

   Die erwähnte Unfallgefahr ist darauf zurückzuführen, dass bei Handhabung der Schweissmuffe ohne eingesteckte Rohrleitungselemente der unter Spannung gesetzte nackte Widerstands draht direkt berührt werden könnte, was bei Kleinspannungen ungefährlich ist, bei der zur Anwendung kommenden erhöhten Netzspannung aber ernsthafte Folgen haben kann.



   Es sind zwar bereits Schweissmuffen bekannt, bei denen die Widerstands drähte vollständig im Muffenmaterial eingebettet sind. Die Herstellung dieser Muffen ist jedoch schwierig, da sich die aus nacktem Draht bestehenden Wicklungen beim Spritzprozess leicht verschieben können, was später beim Schwei ssen zu ungleichmässigen thermischen Flächenbelastungen oder gar zu Kurzschlüssen führt.



   Das erfindungsgemässe Verfahren ist dadurch gekennzeichnet, dass ein zuvor mit dem Muffenmaterial oder artsverwandtem Kunststoff umhüllter Heizdraht um einen Dorn oder eine Hülse zu einer Wicklung gewunden und, eingelegt in ein Spritzwerkzeug, beim Spritzen des Muffenkörpers in diesen eingebettet und festgehalten wird. Die nach diesem Verfahren hergestellte Schweissmuffe ist dadurch gekennzeichnet, dass der ummantelte Heizdraht monofil gewickelt ist und seine Anschlüsse je in der Nähe eines Muffenendes an die Mantelfläche herausgeführt sind.



   Durch diese Massnahme gelingt es, eine Schweissmuffe zu schaffen, die sich rationell herstellen lässt und direkt mit Netzstrom verschweisst werden kann, wobei ausserdem ein elektrischer Berührungsschutz bezüglich des Widerstanddrahtes besteht.



   In der Zeichnung sind Ausführungsbeispiele des Erfindungsgegenstandes dargestellt, Es zeigen:  
Fig. 1 die Vorderansicht einer Schweissmuffe,
Fig. 2 einen Schnitt durch eine Muffenpartie mit Steckbuchse,
Fig. 3 eine Muffenhälfte im Schnitt,
Fig. 4 einen Schnitt durch eine Muffe mit eingesteckten Rohren,
Fig. 5 einen Schnitt durch eine Muffe, zusammen mit einem T-förmigen Rohrbau-Formstück.



   Die Muffe 1 ist als zylindrischer Kunststoffteil ausgebildet und weist in ihrem Innern einen Widerstandsdraht 3 auf. Als Muffenmaterial eignen sich vor allem Polyäthylen, Polypropylen, Polystyrol und Polyamid. Der Widerstandsdraht 3 ist an seinen Enden mit je einer Steckbuchse 4 verbunden, die nahe der beiden Stirnseiten in die Muffe eingelegt sind. Die Axen dieser Steckbuchsen 4 verlaufen rechtwinklig zur Muffenaxe. Anstelle einer durchgehenden Wicklung könnten auch zwei zur Mitte symmetrisch liegende, miteinander verbundene Windungszonen vorgesehen werden. Im Bereiche der Steckbuchsen 4 befindet sich eine warzenförmige Erhebung 2, deren Zweck später noch erläutert wird. Der Widerstandsdraht 3 ist mit einer Ummantelung 3' versehen, so dass jede Windung von der benachbarten durch dazwischenliegendes Material getrennt ist.

   Der Widerstandsdraht ist mit diesem Mantel versehen, bevor er auf einem Dorn oder einer Hülse zu einer Wicklung gewunden und dann in das Innere eines Spritzwerkzeuges eingelegt wird.



  Für die Ummantelung dient der gleiche Kunststoff wie für die Muffe oder aber ein artsverwandter Kunststoff, der sich mit dem Muffenmaterial leicht verbindet. Die Bindung zwischen der Ummantelung und dem Muffenmaterial gibt dem Draht einen guten Halt gegen seitliches Verschieben und vermindert damit das Risiko von Kurzschlüssen zwischen benachbarten Drahtwindungen während des Schweissprozesses. Der Mantel des Heizdrahtes begrenzt den Muffenbohrungsdurchmesser und liegt direkt gegen das zu verschweissende Rohrende an, ohne dass zwischen dem Rohr und dem Mantel der Heizwicklung sich noch eine Zwischenschicht aus Muffenmaterial befindet. Der Querschnitt der Drahtummantelung 3' wird vorzugsweise rund gewählt.



  Der Draht ist so gewickelt, dass sich die einzelnen Ummantelungen berühren. Durch Veränderung der Manteldicke kann die Windungsdichte beeinflusst werden.



   Die Verbindung des Drahtes 3 mit den Steckbuchsen 4 erfolgt in der Weise, dass das Drahtende abisoliert, in eine Rille 10 von konischer Querschnittform eingelegt und darin festgeklemmt wird.



  Infolge des Schrumpfprozesses des nach dem Spritzvorgang erkaltenden Kunststoffes wird dieses Drahtende noch tiefer in die Rille 10 hineingepresst und gleichzeitig die Steckbuchse 4 in ihrer Lage festgehalten. Die warzenförmige Erhebung 2 wirkt mit einem Stift 11 eines Anschlusssteckers 6 so zusammen, dass die Kontaktstifte des Steckers erst dann elektrisch mit dem Heizstromkabel verbunden werden, wenn diese ganz in die Anschlussbuchsen 4 der Muffe 1 eingesteckt sind. Die Drahtummantelung 3' vervollständigt durch Verhinderung einer direkten Drahtberührung die elektrische Sicherheit der Schweissmuffe.



   Durch die wulstartige Materialanhäufung 1' kann die Wanddicke der Muffe unabhängig von der Steckbuchsenhöhe gewählt werden. Ausserdem eignet sich diese Erhebung als Kraftansatz beim Richten (Verdrehen) der Muffe vor dem Verschweissen.



   In Fig. 4 sind zwei Rohre 8 mit Hilfe der Muffe 1 verbunden. Ein zwischen den Stirnseiten der Rohre eingelegter federnder Ring 7 greift in eine Nut der Muffenbohrung ein und wirkt als Anschlag. Dadurch wird verhütet, dass die Muffe vor dem Schweissprozess mehr als vorgesehen über eines der Rohrenden geschoben werden kann. Bei Verwendung der Muffe als Schiebemuffe kann der Ring 7 entfernt werden.



   In Fig. 5 ist ein T-Rohrstück 9 dargestellt, an dessen Enden Rohre 8 mit Hilfe von   Schweissmuffen    1 angeschlossen sind. Da der Innendurchmesser der Schweissmuffe 1 dem Aussendurchmesser der Rohre 8 entspricht, kann die Muffe, beispielsweise zwecks Erleichterung der Leitungsmontage, vorübergehend vollständig über das Rohr geschoben werden. Das T-Stück hingegen ist an den Anschlusspartien je mit einer Schulter 9' versehen, deren Lage so gewählt ist, dass der Abstand bis zur Stirnfläche einer halben Muffenlänge entspricht. Auf diese Weise kann die Muffe vor der Verschweissung nur bis an diese Schulter geschoben werden, was das richtige Placieren der Muffe erheblich erleichtert.   



  
 



     Plastic welding socket and process for their manufacture
The invention relates to a method for producing a plastic welding socket for connecting pipeline elements made of thermoplastic material using heating wire windings which are embedded in the welding socket, are connected to an electrical power source during the welding process and remain inside the connection point after the welding process.



   The invention also relates to a welding socket which is produced by the method mentioned.



   When welding such sleeves, the welding voltage was usually limited to a maximum of 50 V in order to avoid extensive electrical safety measures. The disadvantage here is the need for a relatively heavy transformer, which has the task of stepping down the usual line voltage. Heavy welding equipment is a serious obstacle to the general use of this welding process on building sites, etc. By omitting the transformer, the weight of the heating current regulators can be reduced significantly. The direct extraction of the electrical current for the welding process from the line network leads to increased welding voltages.

   These harbor the risk of accidents and impair the functional reliability of welding sleeves of conventional design, as the risk of short circuits between adjacent wire windings increases. Slight shifts in the bare wire windings during the manufacture of the socket, for example during the injection molding process or during the welding process, can lead to short circuits when the increased voltage is used. This risk is particularly great with the usual bifilar winding type, in which the entire voltage difference occurs between two adjacent conductors.

   The risk of accidents mentioned is due to the fact that when handling the welding socket without the pipeline elements inserted, the live resistance wire could be touched directly, which is harmless with extra-low voltages, but can have serious consequences with the increased mains voltage.



   Welding sleeves are already known in which the resistance wires are completely embedded in the sleeve material. The manufacture of these sleeves is difficult, however, since the bare wire windings can easily shift during the injection molding process, which later leads to uneven thermal surface loads or even short circuits during welding.



   The method according to the invention is characterized in that a heating wire previously covered with the sleeve material or art-related plastic is wound around a mandrel or a sleeve to form a winding and, placed in an injection mold, is embedded and held in the sleeve body during injection molding. The welding socket produced according to this method is characterized in that the sheathed heating wire is wound in a monofilament and its connections are each led out to the jacket surface in the vicinity of a socket end.



   This measure makes it possible to create a welding sleeve that can be produced efficiently and welded directly with mains current, and there is also electrical contact protection with regard to the resistance wire.



   In the drawing, exemplary embodiments of the subject matter of the invention are shown.
Fig. 1 is the front view of a welding socket,
2 shows a section through a socket section with a socket,
3 shows a sleeve half in section,
4 shows a section through a sleeve with inserted pipes,
5 shows a section through a sleeve, together with a T-shaped pipe construction fitting.



   The sleeve 1 is designed as a cylindrical plastic part and has a resistance wire 3 in its interior. Polyethylene, polypropylene, polystyrene and polyamide are particularly suitable as sleeve material. The resistance wire 3 is connected at its ends to a socket 4 each, which are inserted into the sleeve near the two end faces. The axes of these sockets 4 run at right angles to the Muffenaxe. Instead of a continuous winding, it would also be possible to provide two interconnected winding zones that are symmetrical to the center. In the areas of the sockets 4 there is a wart-shaped elevation 2, the purpose of which will be explained later. The resistance wire 3 is provided with a sheathing 3 ', so that each turn is separated from the adjacent one by intervening material.

   The resistance wire is provided with this jacket before it is wound into a winding on a mandrel or a sleeve and then inserted into the interior of an injection molding tool.



  The same plastic is used for the sheathing as for the sleeve or a type-related plastic that easily connects to the sleeve material. The bond between the sheathing and the sleeve material gives the wire a good hold against lateral displacement and thus reduces the risk of short circuits between adjacent wire turns during the welding process. The sheath of the heating wire limits the sleeve bore diameter and lies directly against the pipe end to be welded without an intermediate layer of sleeve material between the pipe and the jacket of the heating coil. The cross section of the wire sheathing 3 'is preferably selected to be round.



  The wire is wound so that the individual sheaths touch each other. The winding density can be influenced by changing the jacket thickness.



   The connection of the wire 3 to the sockets 4 takes place in such a way that the wire end is stripped, inserted into a groove 10 with a conical cross-sectional shape and clamped therein.



  As a result of the shrinking process of the plastic that cools after the injection molding process, this wire end is pressed even deeper into the groove 10 and at the same time the socket 4 is held in its position. The wart-shaped elevation 2 interacts with a pin 11 of a connector 6 in such a way that the contact pins of the connector are only electrically connected to the heating current cable when they are fully inserted into the connector sockets 4 of the sleeve 1. The wire sheathing 3 'completes the electrical safety of the welding socket by preventing direct wire contact.



   Because of the bead-like accumulation of material 1 ', the wall thickness of the sleeve can be selected independently of the socket height. This elevation is also suitable as a force application when straightening (twisting) the sleeve before welding.



   In FIG. 4, two pipes 8 are connected by means of the sleeve 1. A resilient ring 7 inserted between the end faces of the pipes engages in a groove in the socket bore and acts as a stop. This prevents the sleeve from being pushed more than intended over one of the pipe ends before the welding process. When using the sleeve as a sliding sleeve, the ring 7 can be removed.



   In FIG. 5, a T-pipe section 9 is shown, at the ends of which pipes 8 are connected with the aid of welding sleeves 1. Since the inside diameter of the welding socket 1 corresponds to the outside diameter of the pipes 8, the socket can temporarily be pushed completely over the pipe, for example to facilitate the line assembly. The T-piece, on the other hand, is provided with a shoulder 9 'at each of the connection parts, the position of which is selected such that the distance to the end face corresponds to half a sleeve length. In this way, the sleeve can only be pushed up to this shoulder before welding, which makes it much easier to place the sleeve correctly.


    

Claims (1)

PATENTANSPRÜCHE I. Verfahren zur Herstellung einer Kunststoff Schweissmuffe zum Verbinden von Rohrleitungselementen aus thermoplastischem Kunststoff unter Verwendung von Heizdrahtwindungen, welche in die Schweissmuffe eingebettet sind, beim Schweissprozess an eine elektrische Stromquelle angeschlossen werden und nach dem Schweissvorgang im Innern der Verbindungsstelle verbleiben, dadurch gekennzeichnet, dass ein zuvor mit dem Muffenmaterial oder artsverwandtem Kunststoff umhüllter Heizdraht um einen Dorn oder eine Hülse zu einer Wicklung gewunden und, eingelegt in ein Spritzwerkzeug, beim Spritzen des Muffenkörpers in diesen eingebettet und festgehalten wird. PATENT CLAIMS I. A method for producing a plastic welding sleeve for connecting pipeline elements made of thermoplastic material using heating wire turns which are embedded in the welding sleeve, are connected to an electrical power source during the welding process and remain inside the connection point after the welding process, characterized in that a Heating wire previously covered with the sleeve material or art-related plastic is wound around a mandrel or sleeve to form a winding and, inserted in an injection molding tool, is embedded and held in the sleeve body during injection molding. II. Schweissmuffe, hergestellt nach dem Verfahren gemäss Patentanspruch I, dadurch gekennzeichnet, dass der ummantelte Heizdraht monofil gewickelt ist und seine Anschlüsse je in der Nähe eines Muffenendes an die Mantelfläche herausgeführt sind. II. Welding sleeve, produced according to the method according to claim I, characterized in that the sheathed heating wire is wound monofilament and its connections are each led out in the vicinity of a sleeve end on the jacket surface. UNTERANSPRÜCHE 1. Schweissmuffe nach Patentanspruch II, dadurch gekennzeichnet, dass sich die Mäntel der Heizdrähte berühren. SUBCLAIMS 1. Welding sleeve according to claim II, characterized in that the sheaths of the heating wires touch. 2. Schweissmuffe nach Patentanspruch II, da durch gekennzeichnet, dass im Bereich der Anschlüsse an der Muffenaussenwand mindestens eine auf den Anschlussstecker abgestimmte warzenartige Erhebung vorhanden ist 3. Schweissmuffe nach Patentanspruch II, dadurch gekennzeichnet, dass die Anschlüsse mit im Muffenmaterial eingebetteten Steckbuchsen versehen sind, an deren Umfang eine im Querschnitt konische Rille angeordnet ist zwecks Festklemmung des nack ten Drahtendes. 2. Welding sleeve according to claim II, characterized in that in the area of the connections on the sleeve outer wall at least one on the Connector matching wart-like elevation is present 3. Welding sleeve according to claim II, characterized in that the connections are provided with sockets embedded in the sleeve material, on the circumference of which a conical cross-section Groove is arranged for the purpose of clamping the bare wire end. 4. Schweissmuffe nach Patentanspruch II, gekennzeichnet durch eine wulstartige Materialanhäufung an der Muffenaussenseite über der mit den Steckbuchsen besetzten Partie. 4. Welding sleeve according to claim II, characterized by a bead-like accumulation of material on the outside of the sleeve over the area occupied by the sockets. 5. Schweissmuffe nach Patentanspruch II, dadurch gekennzeichnet, dass der Mantel des Heizdrahtes den Muffenbohrungsdurchmesser begrenzt 5. Welding socket according to claim II, characterized in that the jacket of the heating wire limits the socket bore diameter
CH1272262A 1962-10-30 1962-10-30 Plastic welding socket and process for their manufacture CH396536A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CH1272262A CH396536A (en) 1962-10-30 1962-10-30 Plastic welding socket and process for their manufacture
DE19631554861 DE1554861B1 (en) 1962-10-30 1963-10-15 Process for the production of a welding fitting made of thermoplastic material with heating wire windings embedded therein
AT837563A AT257146B (en) 1962-10-30 1963-10-18 Process for the production of a welding socket from thermoplastic material and a welding socket produced according to this

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1272262A CH396536A (en) 1962-10-30 1962-10-30 Plastic welding socket and process for their manufacture

Publications (1)

Publication Number Publication Date
CH396536A true CH396536A (en) 1965-07-31

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CH1272262A CH396536A (en) 1962-10-30 1962-10-30 Plastic welding socket and process for their manufacture

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AT (1) AT257146B (en)
CH (1) CH396536A (en)
DE (1) DE1554861B1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2392796A1 (en) * 1977-06-03 1978-12-29 Sturm Werner METHOD OF MANUFACTURING A WELDED SLEEVE IN ELECTRIC PLASTIC MATERIAL
EP0036963B1 (en) * 1980-03-31 1984-02-08 Georg Fischer Aktiengesellschaft Welding socket for thermoplastic materials, method and apparatus for its manufacture
EP0183188A2 (en) * 1984-11-29 1986-06-04 Von Roll Ag Electrically weldable connecting element for the connection of/with conduit parts
DE3720577A1 (en) * 1986-07-31 1988-02-04 Meier Schenk Ag Weld sleeve for producing a pipe connection, and use of said weld sleeve

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH658426A5 (en) * 1983-02-04 1986-11-14 Fischer Ag Georg METHOD FOR WELDING LINE ELEMENTS FROM THERMOPLASTIC MATERIAL AND A DEVICE SUITABLE FOR THIS.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1071433B (en) * 1959-12-17
DE863255C (en) * 1951-01-22 1953-01-15 Chem Fab Knoell K G Method and device for welding the abutting edges of thermoplastic plastic films when they are used as floor coverings
AT211042B (en) * 1955-07-22 1960-09-10 Sued West Chemie Gmbh Connection element for welding thermoplastic, interlocking molded bodies
DE1048106B (en) * 1956-05-03 1958-12-31 Sued West Chemie Gmbh Fittings to be connected by welding, in particular fittings, made of thermoplastics
DE1111814B (en) * 1956-08-31 1961-07-27 Sued West Chemie Gmbh Process for the production of a welding fitting suitable as a connecting socket for plastic pipes
NL236188A (en) * 1958-02-17
DE1831776U (en) * 1960-12-21 1961-05-25 Schock & Co Gmbh PLASTIC STRIP.

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2392796A1 (en) * 1977-06-03 1978-12-29 Sturm Werner METHOD OF MANUFACTURING A WELDED SLEEVE IN ELECTRIC PLASTIC MATERIAL
US4224505A (en) * 1977-06-03 1980-09-23 Von Roll Ag Electrically welding plastic sleeve
EP0036963B1 (en) * 1980-03-31 1984-02-08 Georg Fischer Aktiengesellschaft Welding socket for thermoplastic materials, method and apparatus for its manufacture
EP0183188A2 (en) * 1984-11-29 1986-06-04 Von Roll Ag Electrically weldable connecting element for the connection of/with conduit parts
EP0183188A3 (en) * 1984-11-29 1987-09-09 Von Roll Ag Electrically weldable connecting element for the connection of/with conduit parts
DE3720577A1 (en) * 1986-07-31 1988-02-04 Meier Schenk Ag Weld sleeve for producing a pipe connection, and use of said weld sleeve

Also Published As

Publication number Publication date
DE1554861B1 (en) 1971-01-07
AT257146B (en) 1967-09-25

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