Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-03-17
2001-10-30
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S650000, C340S464000, C219S229000, C219S497000
Reexamination Certificate
active
06310557
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to electrical monitoring devices, and more particularly is a circuit and device to detect grounding problems in electrical soldering irons.
BACKGROUND OF THE INVENTION
Active and passive electronic components are known to be very sensitive to electrical overstress. It is therefore important for electrical soldering irons, which make frequent contact with such components, to be totally free of static and dynamic electrical potentials.
The tip and all externally exposed metal parts of a typical laboratory grade soldering iron are therefore grounded. The low ohmic grounding connection is usually made through the “green wire” of the Power Cord. However, repeated flexing of the Power Cord during soldering operations may cause the conductors In the Power Cord to break. A break in one or both of the heating current carrying conductors is immediately obvious because the soldering iron will no longer produce heat. A break in the “green grounding wire”, however, is usually not readily noticed, and can thus exist for a long period of time.
When the grounding connection is no longer functional, electrical potentials of sufficient amplitude to cause latent or permanent damage may develop on the soldering iron tip. The potentials may be due either to the accumulation of Electrostatic Charge or to the coupling of alternating voltage potentials through parasitic capacitors between the heating element of the soldering iron and exposed metal on the soldering iron.
The circuit and device of the present invention allow for ongoing monitoring of the integrity of the grounding connection of the soldering Iron tip. The present invention exploits the fact that a soldering iron tip is frequently cleaned by wiping on a suitable leaning device.
The most widely used cleaning device is a moist sponge. A moist sponge usually is conductive because the water in it is highly contaminated with ionic compounds which naturally exist in the sponge and with deposits of ionic compounds that are typically found in soldering fluxes and which are deposited on the sponge during the wiping action. An electrical circuit can thus be established which comprises the soldering iron tip, the conductive sponge, and the safety ground.
Other cleaning devices use metallic sponges that are similar to steel wool but that are made out of a copper or bronze wire mesh. These sponges too are conductive, and thus can be made part of an electrical circuit as described above.
The cleaning device, whether natural or synthetic sponge or wire mesh, can be an integral part of a soldering station or it can be a stand-alone device.
Accordingly, it is an object of the present invention to provide a means to detect grounding problems in soldering irons that are in use.
It is a further object of the present invention to provide a method of monitoring the grounding connection that makes use of commonly used equipment.
It is a still further object of the present invention to provide a way to continuously monitor the grounding connection of the soldering iron.
SUMMARY OF THE INVENTION
The present invention is a circuit and device to detect grounding problems in electrical soldering irons. The device comprises a cleaning sponge in electrical connection with a sensing element. The sensing element is connected to the controlling circuitry and to a safety grounding point, such as a screw of a face plate of an electrical outlet. The circuitry includes LED's which indicate when the grounding mechanism of the soldering iron is functional, and when its grounding connection is broken. The controlling circuitry tests for a low ohmic path between the electrical safety ground and the metal parts of a soldering iron which may make contact with an electronic component. Further circuits indicate when the cleaning sponge has gone dry, and when the operator has an unsafe level of electrostatic charge.
An advantage of the present invention is that current soldering work stations can be easily retrofitted to include the device. The device can also be manufactured as a stand-alone item.
Another advantage of the present invention is that it continually monitors the grounding connection with no required action on the part of the operator.
These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and as illustrated in the drawings.
REFERENCES:
patent: 3290668 (1966-12-01), Perretta
patent: 4859992 (1989-08-01), Hoigaard
patent: 5083117 (1992-01-01), Hoigaard
patent: 5463379 (1995-10-01), Campbell et al.
patent: 5519384 (1996-05-01), Chanudet et al.
Heymann Steven B.
Nelsen Lyle
Nguyen Tai T.
NOVX Corporation
The Kline Law Firm
Wu Daniel J.
LandOfFree
Circuit and device to detect grounding problems in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit and device to detect grounding problems in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit and device to detect grounding problems in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2616530