Hybrid electric lawnmower

• US 7,728,534 B2
• Filed: 02/02/2007
• Issued: 06/01/2010
• Est. Priority Date: 10/17/2006
• Status: Active Grant

• Current Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Lucas, Justin, Lucas, Ryan Jay, Lucas, Delbert E.
• Primary Examiner(s): Duda; Rina I
• Application Number:
  US11/670,932
• Publication Number:
  US 20080098703A1
• Time in Patent Office: 1,215 Days
• Field of Search: 318/599, 318/811, 318/139, 318/432, 56/101, 56/106, 56/108, 56/111
• US Class Current: 318/139
• CPC Class Codes: A01D 69/025 Electric hybrid systems

Abstract

A hybrid electric lawnmower is described which includes a first and a second electric motor operating blades and the ability to drive the motors from either 120 VAC line voltage or from a battery pack. There is a user selectable power selection switch for switching between DC or AC power and also a boost and conserve feature which allows for increased speed of the blade as necessary. Running the mower at the conserve setting prolongs battery pack duration per charge. Power supply and control systems allow the user to select operation of the motors in either series or parallel configuration depending on the power source.

Claims

1. A hybrid mower with boost and conserve power feature comprising:

a mower deck with a first and a second rotating blade affixed to a first and a second DC motor;

a power control module in electrical control of said first and said second DC motors, said power control module in electrical connection with an AC power input line and a battery pack, said power control module having a power source switch selectively connecting said AC power input line and said battery pack with said first and said second DC motors, wherein said power control module controls the motor speed of said first and second DC motors by selecting a first power level output or a second power level output through a boost conserve switch;

a current inverter on said power control module converting AC current from said AC power input line to DC current;

said power source switch alternatively connecting said first and said second DC motors to said current inverter or said battery pack, wherein said power source switch has a first power selection setting and a second power selection setting, said first setting placing said first and said second DC motors in a series configuration and said second setting placing said first and said second DC motors in parallel configuration.

2. The hybrid mower of claim 1 wherein said current inverter is electrically positioned between said AC power input line and said DC power output of said power control module.

3. The hybrid mower of claim 2 wherein said current inverter is a rectifier and filter combination.

4. The hybrid mower of claim 1 wherein said current inverter includes a step down controller.

5. The hybrid mower of claim 4 wherein said step down controller includes a voltage rectifier and a pulse width modulator.

6. The hybrid mower of claim 1 wherein said first and said second DC motor speed for said second power output is above about 15,000 feet per minute blade speed and said DC motor speed for said first power output speed is below about 14,000 feet per minute blade speed.

7. The hybrid mower of claim 1 wherein said first and said second DC motor has a voltage input above 70 volts at said first power output of said power control module and about 60 volts at said second power output of said power control module.

8. The hybrid mower of claim 1 wherein said first and said second DC motor are in parallel configuration with said power control module.

9. The hybrid mower of claim 1 wherein said power selection switch is a three pole double throw switch, said switch connected to said battery pack, to said current inverter and to said first and said second DC motors.

10. A dual blade electric lawn mower, comprising:

a mower housing on which is mounted a first and a second DC motor, said first motor affixed to a blade turning below said housing, said second DC motor affixed to a blade turning below said housing;

a power supply connected to both said first and said second DC motor, said power supply including a battery pack and plug connector;

a power selection switch allowing electrical connection of said first and said second motor to either said plug connector or said battery pack;

wherein said power selection switch alternatively connects said first and said second motor in a parallel configuration when said first and said second motor are electrically connected to said battery pack and in a series configuration when said first and said second motor are electrically connected to said plug connector.

11. The dual blade electric mower of claim 10 further including a current rectifier electrically positioned between said plug connector and said power selection switch.

12. The dual blade electric mower of claim 11 wherein said current rectifier is a full bridge rectifier.

13. The dual blade electric mower of claim 11 wherein said power selection switch is a three pole double throw switch electrically connected to said battery pack, said current rectifier and said first and said second DC motor.

14. The dual blade electric mower of claim 10 further including a boost and conserve switch having a first and a second setting, said first setting reducing the voltage to said first and said second DC motor as compared to said second setting.

15. A hybrid electric lawn mower having a first and a second electric motor turning a first and a second cutting blade, comprising:

a mower housing partially surrounding said first and said second cutting blade, said first cutting blade connected to said first electric motor, said second cutting blade connected to said second electric motor, said first and said second electric motor mounted on said housing;

a user selectable power selection switch electrically connecting said first and said second motor to an AC line voltage source or to a DC voltage battery pack;

a current rectifier electrically positioned between said AC line voltage source and said user selectable power selection switch;

said first and said second electric motor placed in series when said power selection switch connects said first and said second motor to said AC line voltage source, said first and said second electric motor placed in parallel when said power selection switch connects said first and said second motor to said battery pack.

16. A two blade electric lawn mower, comprising:

a first and a second blade connected to a first and a second electric motor, said first and said second motor mounted on a lawn mower housing;

a hybrid AC to DC power controller on said electric lawn mower and electrically connected to a power selection switch, said power selection switch also electrically connected to a battery pack;

an interlock handle switch electrically connected to said first and said second motor to engage and disengage said motors;

wherein said first and said second motor are placed in parallel with each other and electrically connected to said power selection switch;

said hybrid AC to DC power controller having a 120 VAC input line connection and a 60 VDC output line connection connected to said power selection switch.

17. A dual motor electric lawn mower having a power selection switch, comprising:

a housing having a first and a second blade mounted to a first and a second DC motor;

a power control including a power selection switch, said power selection switch in electrical communication with an AC power source and a DC power source;

wherein said power selection switch is operable to electrically connect said first and said second motor to said AC power source in a first setting and is operable to electrically connect said first and said second motor to said DC power source in a second setting, said first setting placing said first and said second electrical motors in series connectivity, said second setting placing said first and said second electrical motors in parallel connectivity.