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Weld Blow Detector

IP.com Disclosure Number: IPCOM000089996D
Original Publication Date: 1969-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Donato, SG: AUTHOR

Abstract

The circuit turns off welder 2 and associated automatic manufacturing equipment whenever a weld blow occurs. A weld blow sometimes occurs in welding small electronic parts such as memory core frames if the circuit is interrupted at the weld tip so that arcing tends to occur. When the welder is provided with a voltage limiter to suppress a weld blow, a weld blow can go undetected by the welder operator and work can proceed automatically on defective components. The circuit detects the weld blow and stops welder 2. Transistors 3 and 4 are connected as a differential amplifier. A network of resistors and a capacitor maintains a reference voltage at the base of transistor 4. Tunnel diode 5, a network of resistors, and a capacitor couple the base of transistor 3 to the weld tip of welder 2.

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Weld Blow Detector

The circuit turns off welder 2 and associated automatic manufacturing equipment whenever a weld blow occurs. A weld blow sometimes occurs in welding small electronic parts such as memory core frames if the circuit is interrupted at the weld tip so that arcing tends to occur. When the welder is provided with a voltage limiter to suppress a weld blow, a weld blow can go undetected by the welder operator and work can proceed automatically on defective components. The circuit detects the weld blow and stops welder 2. Transistors 3 and 4 are connected as a differential amplifier. A network of resistors and a capacitor maintains a reference voltage at the base of transistor
4. Tunnel diode 5, a network of resistors, and a capacitor couple the base of transistor 3 to the weld tip of welder 2. The resistors are adjusted to operate diode 5 normally in its low-voltage, peak current state and it maintains transistor 3 nonconducting and transistor 4 conducting. Diode 5 turns on in response to the momentary voltage rise that accompanies a weld blow and thus turns on transistor 3 and turns off transistor 4. The collector of transistor 4 is connected to the base of transistor 6 that drives electromechanical relay 7 to interrupt the operation of welder 2 and associated equipment when a weld blow occurs. Switch 8 is provided to manually reset diode 5 to its low-voltage state.

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