Hybrid Electric Lawnmower Having Dual Power Supply

• US 20080089674A1
• Filed: 10/18/2006
• Published: 04/17/2008
• Est. Priority Date: 10/17/2006
• Status: Active Grant

• Current Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: DESA IP, LLC
• Inventors: Lucas, Delbert E., Lucas, Justin, Lucas, Ryan Jay
• Granted Patent: US 7,482,768 B2
• Time in Patent Office: Days
• US Class Current: 388/809
• CPC Class Codes: A01D 34/78 electric
• CPC Class Codes: A01D 69/025 Electric hybrid systems

Abstract

A hybrid electric lawnmower having dual power supply is described which includes an electric motor operating the blade and the ability to drive the motor 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 in order to run the motor on either line voltage or based upon the charge of the battery pack.

Claims

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

a mower deck with a rotating blade affixed to an electric DC motor, said motor positioned on an upper surface of said mower deck, said blade rotating below a lower surface of said mower deck;

a power control module affixed to said mower deck and in electrical control of said motor, said power control module in electrical connection with an AC power input line and a DC battery pack, said power control module electrically connected to a user operable power source switch selectively connecting said AC power input line and said battery pack to said DC motor;

a voltage inverter on said power control module converting voltage from said AC power line to DC voltage and driving said DC motor.

2. The hybrid mower of claim 1 wherein said voltage inverter is positioned between said AC power input line and said DC motor.

4. The hybrid mower of claim 1 wherein said voltage 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 battery pack provides greater than about 50 volts DC.

7. The hybrid mower of claim 6 wherein said battery pack is a plurality of batteries connected in series.

8. The hybrid mower of claim 1 further comprising a boost conserve switch which is operative to engage a secondary battery in series with an output voltage of said power control module.

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

9. An electric lawn mower having a dual power supply source, comprising:

a mower housing having a DC motor attached to a rotating grass cutting blade;

a step down controller modifying AC power line voltage to a DC output voltage;

a power selection switch operative to connect said DC motor to said DC output voltage of said step down controller or to a DC output voltage of a battery pack;

an interlock handle switch operably connected to said DC motor to allow said motor to operate when closed and preventing rotation of said blade when open;

said DC motor mechanically turning a blade on a mower housing in response to said power selection switch.

10. The hybrid mower of claim 9 wherein said step down controller includes a voltage inverter.

11. The hybrid mower of claim 10 wherein said voltage inverter is a full bridge rectifier.

12. The hybrid mower of claim 11 wherein said step down controller includes a rectifier in combination with a pulse width modulation circuit.

13. An electric lawnmower in combination with a dual power supply, comprising:

a mower deck with a DC motor electrically connected to a mower handle safety switch, a power selection switch in electrical connection with said mower handle safety switch and to both a battery pack and a power supply controller, said power selection switch operable to electrically connect either said battery pack or said power supply controller to said DC motor, an AC line connected to said power supply controller, said power controller having an inverter for conversion of said voltage from said AC line to DC voltage, and a step down controller for modifying the output voltage of said inverter to generate a modified DC output voltage for said power controller;

wherein said DC mower on said mower deck is user selectable using said power selection switch between said DC output voltage of said power controller and said battery pack;

a plurality of wheels rotatably attached to said mower deck allowing said mower to roll over vegetation to be cut by a blade connected to said DC motor;

said mower deck having an outwardly extending handle, said handle having an affixed interlock safety handle in electrical connectivity with said DC motor to engage and disengage said motor upon release of said handle.

14. The lawnmower of claim 13 wherein said interlock safety handle connected to a safety switch, said safety switch electrically connected to said motor by first connection through a circuit limiter, and connected to said motor by a second connection through a resistive load braking connection which causes said motor to reduce turning at a high rate of speed upon opening of said safety switch.