Electricity: circuit makers and breakers – Solid contact – Push button operated
Reexamination Certificate
2000-02-01
2001-02-20
Scott, J. R. (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Push button operated
C200S526000, C200S528000
Reexamination Certificate
active
06191376
ABSTRACT:
BACKGROUND
The present invention relates to pushbutton switches for use in electrical circuits and in particular to pushbutton switches in which electrical contact is either made or broken substantially simultaneously with a tactile and/or auditory signal from the switch as the switch plunger advances. In one embodiment this may be a momentary ON switch in which electrical contact is made upon advancing the plunger and contact is broken when the plunger retracts.
Pushbutton switches are well known in the art and examples thereof may be found in U.S. Pat. Nos. 3,694,603, 4,055,736, 4,175,222, 4,319,106, 4,345,128, 4,906,808, 5,132,499 and 5,226,529, the disclosures of which are incorporated herein by reference. The foregoing patents disclose pushbutton switches adapted to sequentially open and close an electrical circuit or to sequentially switch a common lead between two alternate portions of a circuit. In addition to the switches shown in the above patents, other designs are known in the art, having a variety of configurations, adapted for similar function.
In prior pushbutton switches having a plunger which advances a rotatable ratchet by camming action, the ratchet advances part of a turn upon advance of the plunger and then, upon release of the plunger, electrical contact is made as the plunger retracts. Upon the next actuation of the switch, electrical contact is broken. Such a switch is shown, for example, in U.S. Pat. No. 5,226,529. Such a switch may be used for an ON-OFF light switch, for example.
It is desirable, however, for electrical contact to be made or broken simultaneously with advance of the ratchet so that the switch operator either hears an audible click or feels a change in pressure on the plunger (or both) as the state of contact is changed. This is particularly desirable in a momentary ON switch where electrical contact is made upon advancing the plunger so that the operator knows when contact is made, and can then release the plunger. Such switches find utility in modern automotive applications where the pushbutton switch provides a momentary signal to a circuit that initiates some action, rather than the action being caused by current through the pushbutton switch directly. A “low tech” example of such signals occurs in some household doorbell systems where chimes continue to play after a momentary push on the doorbell has been released.
SUMMARY OF THE INVENTION
In a presently preferred embodiment, the pushbutton switch comprises a body including a barrel with longitudinally extending internal splines and ways between the splines. A plunger has radially extending lugs in the ways and is longitudinally movable in the barrel. A plurality of longitudinally extending camming teeth on the plunger engage a plurality of longitudinally extending camming teeth on a rotatable ratchet coaxial with the plunger. The ratchet has radially extending dogs which fit into the ways when the plunger is retracted, and come out of the ends of the ways when the plunger is advanced. A rotatable electrical contact member connected to the ratchet stays connected to a common switch terminal and makes or breaks contact with one or more fixed electrical terminals in the switch. The plunger teeth include a leading ramp and a trailing ramp wherein the leading ramp extends a greater distance in the circumferential direction than the trailing ramp.
Since the plunger teeth each having an apex offset from a centerline of the tooth, they advance the ratchet a sufficient distance that electrical contact between the fixed electrical terminal member and the rotatable electrical contact member is made substantially simultaneously with a tactile and/or auditory signal from the switch as the plunger advances toward the ratchet.
REFERENCES:
patent: 3694603 (1972-09-01), Congelliere et al.
patent: 4055736 (1977-10-01), Congelliere
patent: 4175222 (1979-11-01), Buttner
patent: 4308440 (1981-12-01), Buttner
patent: 4317015 (1982-02-01), Buttner et al.
patent: 4319106 (1982-03-01), Armitage
patent: 4345128 (1982-08-01), Buttner et al.
patent: 4906808 (1990-03-01), Buttner et al.
patent: 4939328 (1990-07-01), Smith
patent: 5132499 (1992-07-01), Valenzona et al.
patent: 5226529 (1993-07-01), Valenzona
patent: 1362299 (1964-09-01), None
Christie Parker & Hale LLP
Judco Manufacturing Inc.
Scott J. R.
LandOfFree
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