Electric welding muff
AssigneeVon Roll AG
InventorWerner Sturm
Life of this patent
Estimating the term…
Abstract
A thermoplastic synthetic resin sleeve to be slipped over the end of a tubular member to be joined to another such member has a winding of resistance heating wire adjacent the inner surface of the sleeve. Connectors at the ends of the wire are provided to connect the wire to a source of electrified power. Small diameter wire is chosen, the resistance thereof being selected as an inverse function of sleeve diameter, so that an unregulated source of power can be used. A visual indication is provided to indicate when a good weld joint has been made.
Claims13
In an electric welding muff for thermally flowing to produce welded joints between generally tubular members, the muff being of the type comprising a thermoplastic synthetic resin sleeve with an electric resistance heating wire disposed adjacent the inner surface of the sleeve, and means on said wire for connection to a power source, the improvement wherein
- said sleeve having a predetermined nominal diameter, said wire having a predetermined resistance,
- said resistance and said diameter being so related that their product averages approximately 10,075 ohm-mm plus or minus 20 percent, so that the value of the resistance decreases with increasing sleeve diameter,
- whereby the muff is operable with an unregulated source of power.
In an electric welding muff for thermally flowing to produce welded joints between generally tubular members, the muff being of the type comprising a thermoplastic synthetic resin sleeve with an electric resistance heating wire disposed adjacent the inner surface of the sleeve, and means on said wire for connection to a power source, the improvement comprising
- a visible indicator mounted in said sleeve with a portion of said indicator being adjacent said wire, said indicator being movable in a visually apparent manner when said sleeve flows to a predetermined degree.
In an electric welding muff for thermally flowing to produce welded joints between generally tubular members, the muff being of the type comprising a thermoplastic synthetic resin sleeve with an electric resistance heating wire disposed adjacent the inner surface of the sleeve, and means on said wire for connection to a power source, the improvement wherein
- said sleeve has a predetermined nominal diameter, and
- said wire has a predetermined resistance,
- said resistance being a function of said diameter according to the relationship defined by the following values:
- ______________________________________ Nominal Sleeve Wire Diameter Resistance (mm) (Ohms) ______________________________________ 40 264.1 50 216.3 63 171.2 75 145.8 90 115.85 110 90.48 125 68.88 160 53.19 ______________________________________
- whereby said resistance decreases with increasing sleeve diameter to permit the muff to be operated with an unregulated source of power.
Dependencies are inferred from the claim text.