Dual-mode non-isolated corded system for transportable cordless power tools

• US 6,675,912 B2
• Filed: 08/23/2002
• Issued: 01/13/2004
• Est. Priority Date: 12/30/1998
• Status: Expired due to Fees

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Carrier, David A.
• Primary Examiner(s): Smith, Scott A.
• Application Number:
  US10/226,453
• Publication Number:
  US 20020189831A1
• Time in Patent Office: 508 Days
• Field of Search: 173/217, 173/216, 173/164, 310/47, 310/50
• US Class Current: 173/217
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence
• CPC Class Codes: H01H 2009/065 Battery operated hand tools in which the battery and the switch are directly connected
• CPC Class Codes: H01H 9/06 Casing of switch constituted by a handle serving a purpose other than the actuation of the switch, e.g. by the handle of a vacuum cleaner
• CPC Class Codes: H01H 9/52 Cooling of switch parts cooling of contacts H01H1/62
• CPC Class Codes: H02H 7/0852 directly responsive to abnormal temperature by using a temperature sensor in a control circuit H02H7/0833
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

A dual-mode system for inexpensively operating electrically powered double-insulated devices (12), such as hand-held power tools and appliances. The system includes a cordless battery pack (14) that supplies the power and current demands of the device (12) in a cordless mode or a non-isolated corded voltage converter (16) that supplies the necessary power and current demands in a physical envelope commensurate in size and interchangeable with that of the battery pack (14). The corded voltage converter (16) is provided with a non-isolated high efficiency power supply that allows the converter (16) to generate the power and current required by the driven device (12). The double insulation of the driven device (12) negates the need for a transformer-isolated voltage converter. Eliminating the power transformer from the converter significantly reduces the cost of the module (16). Additionally, the need for multiple battery packs and fast rechargers is minimized by the availability of a low-cost converter. The voltage converter (16) includes an inrush current limiter (103) and power conditioner for filtering AC or DC input power. The filtered voltage is chopped by a transformerless buck-derived converter. The chopped voltage is rectified and filtered to provide low-voltage DC power to the drive motor of the powered double-insulated device (12).

Claims

1. A corded/cordless power tool having an exterior and an interior, comprising:

a case for enclosing the power tool;

a motor operable in a preselected voltage range for converting electrical energy to mechanical energy; and

a power interface coupled to the motor, being adapted to interface with either of a first power module and a second power module, each of said power modules for supplying an output having a voltage suitable for powering the power tool, the power interface including;

a power tool terminal block coupled to the power tool for interfacing with the power modules, including;

male terminals for electrically coupling the power tool to the output of the first power module, the male terminals including a positive male terminal and a negative male terminal; and

a first female terminal coupled to one of the male terminals for alternatively connecting the power tool to the output of the second power module;

wherein, the first power module includes female terminals adapted to be received by the corresponding male terminals of the power tool for electrically mating the first power module to the power tool;

wherein, the second power module includes a first male terminal adapted to be received by the first female terminal for electrically mating the second power module to the power tool.

2. The corded/cordless power tool of claim 1 wherein the power tool terminal block further comprises a second female terminal coupled to the other of the male terminals;

wherein, the second power module includes male terminals adapted to be received by the first female terminal and the second female terminal for electrically mating the second power module to the power tool.

3. The corded/cordless power tool of claim 2 wherein the case is double-insulated to prevent the conduction of electrical charge from the interior to the exterior of the power tool.

4. The corded/cordless power tool of claim 2 wherein the first power module is a line power module and the second power module is a battery power module;

said battery power module for supplying a DC voltage from a battery assembly suitable for powering the power tool; and

said line power module for converting line power to a DC voltage suitable for powering the power tool.

5. The corded/cordless power tool of claim 4 wherein the line power module includes a housing in which the female terminals are recessed such that safety requirements for voltage standoff are met.

6. The corded/cordless power tool of claim 4 wherein the line power module includes a housing in which the female terminals are recessed at least 8 mm such that safety requirements are met.

7. The tool of claim 1 comprising:

a cordless battery power supply module for selectively connecting to the electrical interface of the tool to energize the electrical system; and

a corded non-isolated converter power supply for selectively connecting to the electrical interface of the tool to energize the electrical system.