ELECTRICAL CONNECTIONS

• US 3,702,387 A
• Filed: 06/04/1971
• Issued: 11/07/1972
• Est. Priority Date: 06/04/1971
• Status: Expired due to Term

• Current Assignee: Leo I. Klein
• Original Assignee: Leo I. Klein
• Inventors: Klein, Leo I.
• Primary Examiner(s): Staubly, R. F.
• Assistant Examiner(s): Schutzman, L. A.
• Application Number:
  US05/150,010
• Time in Patent Office: 522 Days
• Field of Search: 219/91,117,107 29/611,619,621,628,482 174/77,94R,1 338/299,329
• US Class Current: 219/91.23
• CPC Class Codes: B23K 2101/38 Conductors
• CPC Class Codes: H01C 1/146 the resistive element surrounding the terminal
• CPC Class Codes: H01R 43/0214 Resistance welding H01R43/0228 takes precedence
• CPC Class Codes: H05B 3/06 Heater elements structurally combined with coupling elements or holders
• CPC Class Codes: Y10T 29/49083 Heater type
• CPC Class Codes: Y10T 29/49174 Assembling terminal to elongated conductor

Abstract

In an electric resistance heating element, the invention relates to the assembly of a resistor coil to a terminal pin to provide mechanical and electrical connection therebetween. The assembly is particularly suited for use in strip heaters wherein the coil is connected to the flat head of a terminal bolt. A group of convolutions of the resistor coil are flattened against the bolt head and welded thereto by a resistance welding operation. In the method disclosed, the shank of the bolt is disposed within an opening in one welding electrode of a welding machine with the bolt head overlying the tip of such electrode, and the group of convolutions of the coil are placed against the flat surface of the bolt head. The other welding electrode has a rounded tip and as this electrode is moved toward said one electrode, its rounded tip flattens the group of convolutions in overlapping relation on the flat surface of the bolt head. With the flattened convolutions and the bolt head firmly gripped between the welding electrodes, welding current is caused to flow between the electrodes to weld the flattened convolutions to the flat surface of the bolt head. Those flattened convolutions at the center of the rounded tip of said other electrode are fully fused to the flat surface of the bolt head, whereas the convolutions off the center of such rounded tip have a stick weld to the flat surface. Thus, not only is a low resistance electrical connection made by the fully fused convolutions, but a good mechanical connection is made by the stick-welded convolutions.

Claims

1. The method of electrically and mechanically connecting a resistor coil of an electric strip heater to a flat surface on the head of a terminal bolt which is adapted to be connected to a source of electrical energy, comprising;

disposing the shank of the bolt in an opening in one electrode of a resistance welding machine with the bolt head overlying the tip of the electrode and its flat surface exposed, positioning a group of convolutions of said resistor coil against said flat surface, moving another electrode of said welding machine toward said one electrode so that its tip flattens said group of convolutions between it and said flat surface, said tip being round whereby said convolutions are overlapped as they are flattened, and passing welding current from one electrode through the group of flattened convolutions and said bolt head and to the other electrode while pressing said rounded tip against said flattened convolutions whereby the overlapped convolutions at the center of said rounded tip are fully fused to said flat surface and the overlapped convolutions off the center of said rounded tip have a stick weld to said flat surface.

2. The method of electrically and mechanically connecting a helically coiled resistance wire of an electric heating element to a surface of a terminal pin which is adapted to be connected to a source of electrical energy, comprising:

supporting said terminal pin on a first electrode of a resistance welding machine, supporting a group of convolutions of said resistance wire crosswise of said pin surface with an outer peripheral portion thereof against said pin surface, moving a second electrode of said welding machine toward said first electrode to press against an opposite outer peripheral portion of said group of convolutions and deform the latter from helically coiled form to a flattened condition between said second electrode and said pin surface, and passing welding current from one electrode through the flattened group of convolutions and pin surface to the other electrode to weld said group of flattened convolutions to said terminal pin surface.