Patents Assigned to Solid State Chargers Research and Development Limited
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Patent number: 5266881Abstract: A high current battery charger of the driven blocking oscillator type includes a three-winding transformer. The primary winding is connected in series with the collector-emitter path of a switching power transistor. The secondary winding is connected in series with the collector-emitter path of a sense transistor which responds to the current flowing through the switching power transistor. The tertiary winding is connected in series with the battery, series-connected batteries or series-connected battery packs sought to be recharged, via a diode, which may be connected in parallel with a capacitor. The battery or batteries are charged by current pulses and discharge through the tertiary winding to repolarize the diode (and capacitor if present). The secondary winding is poled, with respect to the tertiary winding so that the blocking oscillator is driven by energy from the battery or batteries.Type: GrantFiled: April 29, 1991Date of Patent: November 30, 1993Assignee: Solid State Chargers Research and Development LimitedInventors: Philip K. Hoffman, Douglas Frey
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Patent number: 4739242Abstract: A multistation charging system is provided for charging batteries within a plurality of cordless tools, appliances or the like, each of which has at least one rechargeable battery therein. A plurality of modules, which act as charging stations, are arranged substantially adjacent to one another. Normally closed pairs of conductive contacts are provided in each of the modules. The electrical pairs of contacts in the modules are connected in a series circuit arrangement with each other. On one of the modules, electrical connection is provided to a single current regulated solid-state charging device which produces charging current pulses. The device may alternatively be in the one module. Each of the modules removably supports a respective tool or appliance and each tool or appliance has means for electrically connecting the respective battery therein within the series circuit arrangement and in series therewith only one wall outlet or a.c. power connection is required.Type: GrantFiled: May 8, 1986Date of Patent: April 19, 1988Assignee: Solid State Chargers Research and Development Limited PartnershipInventors: George W. McCarty, Somers H. Smith, III
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Patent number: 4612491Abstract: A charger for batteries includes a a charging station, which includes a housing. A casing end having an open portion through which batteries to be charged are to be inserted is provided. A constant tension spring within the casing urges the batteries outwardly of the casing. A lid is provided adjacent to the open end of the casing, the lid being movably, pivotably supported on the casing. A stop member is provided on the housing, the stop preventing the lid from being moved to its completely open position when the casing is supported on the housing. A latch arrangement retains the lid in a closed orientation. The batteries in the casing are retained therein by a portion of the lid whenever the lid is pivoted away from its completely open position. Contact means are provided between the housing and casing to provide a path for charging current. A multiple of charging stations can be provided, the multiple stations being electrically and mechanically connected.Type: GrantFiled: July 1, 1985Date of Patent: September 16, 1986Assignee: Solid State Chargers Research & Development Limited PartnershipInventors: George W. McCarty, Somers H. Smith, III
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Patent number: 4531083Abstract: A battery charger which includes terminals for connection to an electric power source, an electrical charging circuit and an operative arrangement for connecting at least one rechargeable battery cell in series with the charging circuit across the terminals. The battery charger has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.Type: GrantFiled: August 18, 1983Date of Patent: July 23, 1985Assignee: Solid State Chargers Research and Development Limited PartnershipInventor: Philip A. Hoffman
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Patent number: 4531084Abstract: A power supply which includes terminals for connection to an electric power source, a storage capacitance, an electrical charging circuit and an operative arrangement for connecting storage capacitance in series with the charging circuit across the terminals. The power supply has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.Type: GrantFiled: August 18, 1983Date of Patent: July 23, 1985Assignee: Solid State Chargers Research and Development Limited PartnershipInventor: Philip A. Hoffman
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Patent number: 4516067Abstract: A power supply which includes terminals for connection to an electric power source, a storage capacitance, an electrical charging circuit and an operative arrangement for connecting the storage capacitance in series with the charging circuit across the terminals. The power supply has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A control stage includes a first transistor, which has a collector-emitter path and a base-emitter path. The transistor is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.Type: GrantFiled: February 29, 1984Date of Patent: May 7, 1985Assignee: Solid State Chargers Research and Development Limited PartnershipInventor: Philip A. Hoffman
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Patent number: 4504774Abstract: A battery charger which includes terminals for connection to an electric power source, an electrical charging circuit and an operative arrangement for connecting at least one rechargeable battery cell in series with the charging circuit across the terminals. The battery charger has a charging circuit which includes a first resistor, a second resistor, a third resistor and a rectifier, constituted by at least one diode, in series. A first transistor, which has a collector-emitter path and a base-emitter path, is operatively connected so that the base-emitter path is connected in parallel with the first resistor. A fourth resistor is provided, the fourth resistor being connected in series with the collector-emitter path of the transistor and the third resistor.Type: GrantFiled: March 7, 1983Date of Patent: March 12, 1985Assignee: Solid State Chargers Research and Development Limited PartnershipInventor: Philip A. Hoffman