Electric drive riding mower

• US 7,610,975 B1
• Filed: 01/10/2000
• Issued: 11/03/2009
• Est. Priority Date: 02/09/1996
• Status: Expired due to Term

• Current Assignee: Toro Company (Toro)
• Original Assignee: Toro Company (Toro)
• Inventors: Gust, Jackie R., Metheny, Eric A., Pavlik, Dennis J., Anderson, Mark S., Tetzlaff, Heinrich F., Lonn, Dana R.
• Primary Examiner(s): VANAMAN, FRANK BENNETT
• Application Number:
  US09/480,044
• Time in Patent Office: 3,585 Days
• Field of Search: 180/65.4, 180/65.8, 180/65.2, 56/133, 56/119, 56/106, 903/930
• US Class Current: 180/65.245
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/44 with two or more cutters
• CPC Class Codes: A01D 34/66 with two or more cutters
• CPC Class Codes: A01D 34/662 to the front of the vehicle
• CPC Class Codes: A01D 34/81 Casings; Housings A01D34/71 takes precedence
• CPC Class Codes: A01D 69/02 electric
• CPC Class Codes: A01D 75/30 Arrangements for trailing two or more mowers
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

An electric drive mower includes an electric traction drive as well as electric drive to the cutting units carried on the mower. A hybrid electric drive system supplies electric power to these motors. The electric drive system includes a genset (an internal combustion engine driving an electrical power generating device such as an alternator) and a battery pack which supply the electric power to the electric motors either individually or jointly. A switch may be provided to permit all battery operation of the mower. A steering system having a non-powered pump is used to effect steering of the steerable wheel(s) of the mower to avoid having a heated oil damage the turf in the event of a leak. A crankshaft driven by a single electric drive motor is linked to all the cutting units through various crankarm and connecting rod linkages to lift and lower the cutting units in a timed manner.

Claims

1. An electrically driven turf maintenance machine, which comprises:

(a) a frame;

(b) a plurality of ground engaging wheels attached to the frame for supporting the frame for movement over the ground;

(c) at least one electric motor operatively connected to at least one of the ground engaging wheels for propelling the wheel to provide traction for the frame;

(d) a plurality of reel cutting units carried on the frame for mowing grass, wherein each reel cutting unit comprises a rotatable cutting reel that sweeps grass against a sharpened bedknife for cutting the grass;

(e) a plurality of electric motors for driving the plurality of reel cutting units with at least one electric motor being carried on each reel cutting unit for powering the rotatable cutting reel of each reel cutting unit; and

(f) an electric drive system carried on the frame for providing electric power to the electric motors, the electric drive system comprising;

(i) an internal combustion engine;

(ii) an electric power generating device mechanically driven by the engine for supplying electric power;

(iii) a battery power source for supplying electric power, wherein the electric power generating device is connected to the battery power source to recharge the battery power source during operation of the internal combustion engine;

(iv) an electric power supply circuit connected to the electric motors to supply electric power to the electric motors at least from either the electric power generating device or from both the electric power generating device and battery power source;

(v) a switch for shutting off the internal combustion engine to thereby disable the electric power generating device, thereby making the battery power source the sole source of electric power for the electric motors, wherein the switch is selectively operable only under the manual control of a user of the machine to allow only the user to select when the battery power source shall serve as the sole source of electric power for the electric motors;

(vi) a display for indicating to a user of the machine different states of charge of the battery power source, wherein the display has a warning indicator that warns the user when the battery has been discharged to a state of charge that is between a substantially fully charged state of charge and a predetermined minimum state of charge to alert the user to a need to recharge the battery by restarting the internal combustion engine if the user so desires; and

(vii) automatically operable lock-out means for preventing operation of the electric motors from only the battery power source when the user operates with the battery power source serving as the sole source of electric power and the state of charge of the battery power source reaches the predetermined minimum level, wherein the lock-out means only prevents operation of the electric motors without the lock-out means automatically restarting the engine such that restarting the engine remains solely under the manual control of the user with the user being required to selectively restart the internal combustion engine at a time solely of the user'"'"'s choosing to permit continued operation of the electric motors.

2. A machine as recited in claim 1, wherein the electric power generating device comprises an alternator.

3. A machine as recited in claim 2, further including a controller for controlling the application of electric power to the electric motors, and wherein the controller is further connected to the magnetic field windings of the alternator to control the operation of the alternator.

4. A machine as recited in claim 1, wherein two of the wheels on the frame are individually driven by separate electric motors each of which are connected to the electric drive system.

5. A machine as recited in claim 4, wherein the machine has a steering wheel to allow the machine to be turned, and further including a controller for controlling the supply of electric power from the electric drive system to the electric motors, wherein the controller has means responsive to a turn effected by movement of the steering wheel to vary the power supplied to the individual electric motors to effect a differential action during the turn.

6. A turf maintenance machine, which comprises:

(a) a movable frame;

(b) at least one electrically powered cutting unit carried on the frame for cutting grass;

(c) an electrically powered traction system for propelling the frame; and

(d) a drive system carried on the frame for powering the cutting unit and the traction system, the drive system including;

(i) an internal combustion engine that powers an electric power generating device that at least at various times partially supplies electrical energy to the cutting unit and the traction system during a hybrid mode of operation;

(ii) a battery power source that also at least at various times partially supplies electrical energy to the cutting unit and the traction system during the hybrid mode of operation and that entirely supplies electrical energy to the cutting unit and the traction system during an all battery mode of operation; and

(iii) a selectively actuable switch having two positions for selecting between the hybrid and all battery modes of operation with the switch in one position thereof deactivating the engine to enter the all battery mode of operation and the switch in the other position activating the engine to enter the hybrid mode of operation, wherein the switch is selectively actuable only by manual control by a user of the machine such that only the user is able to switch back and forth between the hybrid and all battery modes of operation by the user manually moving the switch back and forth between the two positions thereof.

7. A machine as recited in claim 6, wherein the placement of the switch into the position that selects the all battery mode of operation shuts off the internal combustion engine to prevent the internal combustion engine from powering the electric power generating device.

8. An electrically driven turf maintenance machine, which comprises:

(a) a frame;

(b) a plurality of ground engaging wheels attached to the frame for supporting the frame for movement over the ground;

(c) at least one electric motor operatively connected to at least one of the ground engaging wheels for propelling the wheel to provide traction for the frame;

(d) a plurality of reel cutting units carried on the frame for mowing grass, wherein each reel cutting unit comprises a rotatable cutting reel that sweeps grass against a sharpened bedknife for cutting the grass, wherein the reel cutting units are disposed in a predetermined side-to-side distribution and front-to-back distribution of cutting units in a ganged configuration relative to the frame;

(e) a plurality of electric motors for driving the plurality of reel cutting units with at least one electric motor being carried on each reel cutting unit for powering the rotatable cutting reel of each reel cutting unit; and

(f) an electric drive system carried on the frame for providing electric power to the electric motors, the electric drive system comprising;

(i) an internal combustion engine;

(ii) an electric power generating device mechanically driven by the engine for supplying the electric power;

(iii) a battery power source for supplying the electric power; and

(iv) a display having a plurality of current draw indicators for the motors powering the reel cutting units so that the current draw from each reel cutting unit is displayed to an operator of the mower, wherein the display includes a plurality of pictorial symbols with each symbol representing one of the reel cutting units carried on the frame and with the symbols being collectively arranged on the display in a pictorial symbol arrangement that mimics the ganged configuration of the reel cutting units on the frame with some symbols being ahead of other symbols to mimic the front to back distribution of cutting units in the ganged configuration and with some symbols being displaced to the side of other symbols to mimic the side to side distribution on cutting units in the ganged configuration, and wherein the current draw indicator for the motor of a particular cutting unit is arranged adjacent the symbol that represents the particular cutting unit in the pictorial arrangement of cutting units on the display.

9. The machine of claim 8, wherein the current draw indicators each comprise a variable length band whose length is related to the current draw with the band being longer when the current draw is higher and shorter when the current draw is lower.

10. An electrically driven turf maintenance machine, which comprises:

(a) a frame;

(b) a plurality of ground engaging wheels attached to the frame for supporting the frame for movement over the ground;

(c) at least one electric motor operatively connected to at least one of the ground engaging wheels for propelling the wheel to provide traction for the frame;

(d) a plurality of reel cutting units carried on the frame for mowing grass, wherein each reel cutting unit comprises a rotatable cutting reel that sweeps grass against a sharpened bedknife for cutting the grass;

(e) a plurality of electric motors for driving the plurality of reel cutting units with at least one electric motor being carried on each reel cutting unit for powering the rotatable cutting reel of each reel cutting unit; and

(f) an electric drive system carried on the frame for providing electric power to the electric motors, the electric drive system comprising;

(i) an internal combustion engine;

(ii) an electric power generating device mechanically driven by the engine for supplying electric power;

(iii) a battery power source for supplying electric power;

(iv) an electric power supply circuit connected to the electric motors to supply electric power to the electric motors at least from either the electric power generating device or from both the electric power generating device and battery power source; and

(v) a switch for shutting off the internal combustion engine to thereby disable the electric power generating device, thereby making the battery power source the sole source of electric power for the electric motors, wherein the switch is selectively operable under the control of a user of the machine to allow the user to select when the battery power source shall serve as the sole source of electric power for the electric motors; and

(vi) an automatic reel to bedknife adjustment system that is activated to loosen the reel to bedknife adjustments on the reel cutting units whenever the shut off switch is operated by the user enter into an all battery mode of operation.