Leviton Manufacturing Co. v. Slater Electric, Inc.

331 F. Supp. 395, 169 U.S.P.Q. (BNA) 202, 1970 U.S. Dist. LEXIS 10069
CourtDistrict Court, E.D. New York
DecidedSeptember 29, 1970
DocketNo. 67 C 991
StatusPublished
Cited by1 cases

This text of 331 F. Supp. 395 (Leviton Manufacturing Co. v. Slater Electric, Inc.) is published on Counsel Stack Legal Research, covering District Court, E.D. New York primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Leviton Manufacturing Co. v. Slater Electric, Inc., 331 F. Supp. 395, 169 U.S.P.Q. (BNA) 202, 1970 U.S. Dist. LEXIS 10069 (E.D.N.Y. 1970).

Opinion

DOOLING, District Judge.

Plaintiff has sued for a declaratory judgment that its light-dimming devices do not infringe defendant’s Slater patent Reissue 26,119 and that the patent is invalid. Defendant counterclaims for infringement.

It is concluded that the patent is invalid so far as concerns claims 1, 2, 8 and 9, and if the said claims were valid, there would be infringement only by plaintiff's Model No. 671.

The ordinary domestic wall switch used to turn lights on and off is conventionally housed behind a switch plate in a metallic box of standard dimensions, and, electrically, it is located in one of the two wires that conduct the electric power to the lamps. The lights are turned on and off by pressing a button, or [396]*396rotating a short protruding lever, that actuates a switch which opens or closes the electrical circuit mechanically by removing and restoring a segment of the conductor.

Continuously variable dimmers have long been in use, conspicuously, in the theatre. However, until the period of the patent in suit there were no continuously variable dimmers that could be safely and readily installed in the conventional wall switch box in direct substitution for the familiar two-position wall switch. The central question is whether Slater Re. 26,119, which discloses and claims such a device, evinces patentable novelty, and the related questions are whether certain Levitón dimmers infringe one or more claims of Re. 26,119. It appears to be conceded, and the evidence is clear that such dimmers are useful and are now in wide use in wall-switch installations. And the evidence indicates that Slater’s switch was the first in the field.

Slater’s dimmer awaited the availability of the semi-conductor devices; it functions through electronic circuitry, the use of a diode and a silicon controlled rectifier, and adroit deployment of mechanical switching.

The device is designed for use on alternating current electrical circuits. Alternating current reverses polarity a stated number of times a second; for example, domestic house electricity in this area alternates 60 times a second, that is, it rises from zero voltage to a peak of 110 volts of one polarity, falls to zero voltage, then increases to a 110 volt peak of opposite polarity, and returns to zero voltage, repeating the cycle 60 times a second. The cycle is graphically depicted as a sine wave (see, e. g., Ex. AC, p. 42, Fig. 93(A), or Exs. K, L, M). Such an electrical supply can be effectually halved by blocking the passage of voltage of one polarity so that a pulsating direct current, that is, a fluctuating current of only one polarity, is conducted, and no current at all is conducted during the time when the current of opposite polarity would have been conducted but for the blockage. One device, long familiar, used to produce such a “unidirectional” current has been the kind of “electronic” vacuum tube or valve known as a “diode.” Since the discovery of the semiconductors, compact semi-conductor diodes have been available.

In addition to thus making alternating current unidirectional, methods have been evolved to control the point within each half-cycle at which the unidirectional current will start to flow. One method is through the use of a triode in which a third “gating electrode” is used to introduce into the electronic path between the other two electrodes a current used like a trigger to control the time within each half-cycle at which the flow of current will start — the “firing time.” The familiar tube used in earlier electronics in such circuits was the thyratron, a gas-filled tube. Since the introduction of the semi-conductor devices the silicon controlled rectifier (“SCR”) has been developed to perform essentially the office of the thyratron.

Slater’s Re. 26,119 presents a light dimmer that, through exploitating (inter alia) the miniaturization potentials of the semi-conductor diode and SCR can be installed in a wall switch-box as a direct replacement for the familiar wall switch. The Slater dimmer uses an SCR connected in one side of the power line in series with the load (as is the conventional wall switch) across which a time-delay, phase shifting, circuit (energized from the voltage across the SCR) is connected to provide a continuously controllable gating signal to the gate electrode of the SCR, thus controlling the power supplied to the load by controlling the portion of each alternating current half-cycle during which the SCR conducts. The current through the SCR is a unidirectional one that cannot exceed fifty percent of the bidirectional alternating current; hence the Slater device incorporates a mechanical switch arranged to bypass the SCR and connect the load directly into the power line at full power after the SCR has reached maximum con[397]*397duction. The time delay, or phase shifting, circuit is not restricted to any specific circuitry,1 but it is strictly required that it be energized from the one side of the power line in which the load and SCR are connected in series — a requirement dictated by the goal of making the device directly substitutable for a conventional wall switch. The Slater device by its nature requires a manually operable control for the time-delay circuit, a means of bringing the bypass electrical path to the load into operation, and a means of cutting off altogether the flow of current to the load. In the embodiment pictured and described in the patent, the illustrated time delay control means is a variable resistance the wiper arm of which is operated by a rotatable shaft that extends through the switch plate on which the dimmer is mounted, and the shaft is fitted externally with a control knob; disk cams mounted on the rotatable shaft are of a configuration such that at the “off” or counterclockwise extreme of rotation the time delay circuit is switched off and de-energized; at the clockwise or “bright” extreme of rotation, the variable resistance is shorted out and the bypass switch is closed so that full power is applied to the load. The Slater device is housed in an insulating housing fitted with lugs for attaching it to a switch plate, and binding posts for connecting the device in one side of an alternating current power line; provision is made for “heat sink” elements within the housing to dissipate the heat generated by the device.

Slater Re. 26,119 provides also for (and separately claims) a dimmer as described with the addition of a diode, connected in parallel with the SCR and of opposite polarization; that diode does not function until switched into operation when the SCR is conducting at full power (50%); the diode would then pass 50% of the power (though of opposite polarity to the current through the SCR) relieving the SCR of all work; the SCR circuit would then be available to supply continuously variable power from 50% to 100%. The Re-issue patent also outlines and claims, in effect, a twinning of the basic SCR and time-delay circuits to furnish a dimmer operable from substantially zero to 100% by simultaneously varying both polarities of the alternating current.

Claims 1, 2 and 9, used to evaluate the issues of validity and infringement read as follows—

1. A power control and switch device providing substantially continuous control of power supplied to a load over a substantial range of power values comprising
(A) two terminals for connecting said device in series in one side of the two sides of the power line from an alternating current power source supplying current to the load,

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Related

ECC CORPORATION v. Slater Electric, Inc.
336 F. Supp. 148 (E.D. New York, 1971)

Cite This Page — Counsel Stack

Bluebook (online)
331 F. Supp. 395, 169 U.S.P.Q. (BNA) 202, 1970 U.S. Dist. LEXIS 10069, Counsel Stack Legal Research, https://law.counselstack.com/opinion/leviton-manufacturing-co-v-slater-electric-inc-nyed-1970.