Electricity: circuit makers and breakers – Electric switch details – Contact
Reexamination Certificate
1997-07-02
2001-12-04
Luebke, Renee (Department: 2833)
Electricity: circuit makers and breakers
Electric switch details
Contact
C200S535000, C439S188000, C439S630000
Reexamination Certificate
active
06326568
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to the art of electrical switches and, particularly, to a blade switch such as might be used in a card reader.
BACKGROUND OF THE INVENTION
Chip cards presently are used in a variety of applications and comprise a card of approximately the same size as a standard credit card. The card, itself, contains intelligence in the form of a memory circuit. A card reader or card connector is used to detect certain information stored on the card, and is used in applications such as banking machines, cable television decoders or descramblers, and a variety of other uses.
One type of chip card is identified as a “Subscriber's Identification Module” or “SIM” card which is a miniature chip card for use in small hand held devices such as pocket size cellular telephones. The SIM provides user identification in individual telephone handsets and the SIM card reader readily accommodates insertion and removal of the SIM to provide quick identification and easy access by a cellular telephone user.
A typical SIM or other chip card has exposed contact pads for matingly engaging underlying cantilevered contacts of a SIM connector or card reader. Since the card is inserted and removed manually, SIM connectors have had some inherent design difficulties.
One such difficulty in the use of chip cards and their respective readers involves contamination of the exposed contacts which can disintegrate the integrity and reliability of the electrical connection between the card and the underlying contacts. Since chip cards are typically carried by a person and are exposed to a wide range of contaminants, the card reader is exposed to all kinds of dirt or contaminants, particularly with mobile cellular telephone applications or automatic teller machines which involve outdoor use.
Another design difficulty in chip card readers involves the incorporation of means to detect the presence of the card into the card reader. Such detect means signals that the card is fully seated, and are typically in the form of end position or end-of-stroke switches incorported into the card reader to detect complete insertion of the card. These end position switches can be either normally open switches or normally closed switches. When a change in state of the switch is detected, such as if the card is in its completely inserted position, the card reader is activated and data is transmitted from (or to) the chip card.
Because of the portable nature of chip cards and their respective readers and their known exposure to contaminants, known prior art connectors incorporating switches have used expensive and sometimes complicated designs to protect against contaminants and damage and to ensure the integrity and reliability of the system. There is therefore a need for a simple, yet reliable and economic switch design to incorporate in a chip card or SIM reader or connector. The present invention is directed to satisfying this need and solving the various problems discussed above.
SUMMARY OF THE INVENTION
An object, therefore, of the invention is to provide a new and improved electrical switch assembly of the character described.
In the exemplary embodiment of the invention, the switch assembly includes a first stamped and formed switch contact having a base and an integral first contact arm folded over the base. The contact arm has an upwardly facing contact surface. A second stamped and formed switch contact has a base and an integral spring contact arm folded into cantilevered position above the base. The spring contact arm has a distal end folded thereunder to define a downwardly facing contact surface opposing the upwardly facing contact surface and spaced therefrom in a normally open condition of the switch assembly.
With the above unique structural combination, movement of the spring contact arm of the second switch contact toward the first contact arm of the first switch contact causes engagement and relative wiping action between the contact surfaces. The wiping action functions to continually clean the contact surfaces by removing contaminants therefrom. In addition, the first and second switch contacts can be stamped from a common sheet of metal material with the contact surfaces being formed from the same side of the metal sheet. This facilitates economical and efficient selective plating of the contact surfaces.
As disclosed herein, the contact arms of the first and second switch contacts are disposed in a side-by-side relationship. The distal end of the spring contact arm has a transverse extension, with the downwardly facing contact surface on the underside of the extension so as to overlie the upwardly facing contact surface of the first contact arm. The base of the second switch contact has a raised abutment surface at a level coincident with the upwardly facing contact surface of the first contact arm.
The switch assembly also includes a housing having a top wall over the switch assembly. The top wall has an opening. The spring contact arm has an upwardly projecting actuator portion extending through the opening. The housing substantially encloses the switch assembly except for the upwardly projecting actuator portion. This protects the interior of the assembly from ingress of dirt and other contaminating material.
Lastly, the invention contemplates a method of fabricating the switch assembly from a sheet of conductive metal material to form the contact structural combination described above which facilitates easy selective plating of the contact surfaces.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.
REFERENCES:
patent: 674398 (1901-05-01), Bower
patent: 2469560 (1949-05-01), Isserstedt
patent: 4191867 (1980-03-01), Feaster
patent: 4366351 (1982-12-01), Ditzig
patent: 4900273 (1990-02-01), Pernet
patent: 5013255 (1991-05-01), Juret et al.
patent: 5330363 (1994-07-01), Gardner et al.
patent: 5331123 (1994-07-01), Kimbell et al.
patent: 5334034 (1994-08-01), Reichardt et al.
patent: 5334827 (1994-08-01), Bleier et al.
patent: 5370544 (1994-12-01), Reichardt et al.
patent: 5463210 (1995-10-01), Imura
patent: 5599203 (1997-02-01), Broschard, III
patent: 5670769 (1997-09-01), Pernet
patent: 5673180 (1997-09-01), Pernet
patent: 5775937 (1998-07-01), Bricaud et al.
patent: 5807124 (1998-09-01), Bricaud et al.
patent: 5857857 (1999-01-01), Fukuda
patent: 5863216 (1999-01-01), Tsuji et al.
patent: 5871368 (1999-02-01), Erdner et al.
patent: 5924881 (1999-07-01), Yasushi et al.
patent: 0 516 943 B1 (1992-04-01), None
patent: 0366513B1 (1989-10-01), None
patent: 0490860A1 (1991-12-01), None
patent: 0516943B1 (1992-04-01), None
patent: 0 516 943 B1 (1992-08-01), None
patent: 0617488A1 (1994-03-01), None
patent: 0656597A1 (1994-06-01), None
patent: 0656598A1 (1994-06-01), None
patent: 8-7710 (1996-01-01), None
patent: WO 95/18421 (1995-07-01), None
patent: WO 96/29671 (1996-09-01), None
Martucci Roberto
Previato Mario
Zuin Gianni
Caldwell Stacey E.
Luebke Renee
Molex Incorporated
LandOfFree
Blade switch assembly for a card reader does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Blade switch assembly for a card reader, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blade switch assembly for a card reader will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2579089