Power head assembly for electric grass cutting device

• US 5,819,513 A
• Filed: 08/29/1995
• Issued: 10/13/1998
• Est. Priority Date: 09/22/1993
• Status: Expired due to Fees

• Current Assignee: Briggs & Stratton Corporation
• Original Assignee: Briggs & Stratton Corporation
• Inventors: Braun, Michael, Johnson, Gary S., Bruener, Patrick
• Primary Examiner(s): MELIUS, TERRY L
• Application Number:
  US08/521,295
• Time in Patent Office: 1,141 Days
• Field of Search: 56/11.9, 56/10.8, 56/12.1, 56/1, 56/DIG. 9
• US Class Current: 56/11.9
• CPC Class Codes: A01D 2034/6843 Control levers on the handle of the mower
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/6806 Driving mechanisms for the cutters A01D34/76
• CPC Class Codes: A01D 34/74 Cutting-height adjustment
• CPC Class Codes: A01D 34/78 electric
• CPC Class Codes: A01D 34/81 Casings; Housings A01D34/71 takes precedence
• CPC Class Codes: A01D 34/82 Other details
• CPC Class Codes: A01D 34/828 Safety devices
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: Y10S 56/09 Detachable implement

Abstract

The power head assembly for a cordless electric lawnmower has a removable upper housing that includes two spaced batteries, and a lower housing that is mounted to the deck of the grass cutting device. The upper housing has a handle, and at least one quick disconnect terminal that engages a mating quick disconnect terminal affixed to the lower housing. The lower housing includes an electric motor that is disposed between the two batteries when the upper housing is in place. A portion of the electric motor is located below the deck to further reduce the overall height of the device. The lower housing is mounted to the deck by several bolts which are placed in the same mounting pattern used to mount gasoline engines to a deck, so that the same decks may be used for both the cordless electric and gasoline-powered lawnmowers.

Claims

1. A power head assembly for a cordless electric grass cutting device, comprising:

a first housing and a second housing;

an electric motor substantially enclosed by said first housing, said motor having a rotatable output shaft and a shaft centerline;

a first battery substantially enclosed by said second housing, said first battery being disposed on a first side of said motor when said second housing is adjacent to said first housing;

a second battery substantially enclosed by said second housing, said second battery being disposed on a second side of said motor when said second housing is adjacent to said first housing; and

quick disconnect terminal means for electrically connecting said first and second batteries in said second housing to said motor in said first housing without the use of a tool, and for electrically disconnecting said first and second batteries from said motor without the use of a tool.

2. The power head assembly of claim 1, wherein said quick disconnect terminal means includes:

a first quick disconnect terminal interconnected with said upper housing; and

a second quick disconnect terminal interconnected with said first housing.

3. The power head assembly of claim 2, further comprising:

first and second tongues or grooves disposed on opposite sides of said first terminal; and

the other of first and second grooves or tongues disposed on opposite sides of said second terminal, said first and second grooves engaging said first and second tongues respectively.

4. The power head assembly of claim 1, further comprising:

a handle affixed to an upper end of said second housing.

5. The power head assembly of claim 1, further comprising:

a control circuit, disposed within a cavity in said first housing, that controls the power to said motor; and

a plurality of apertures in said lower housing that are used to mount said first housing to a lawnmower deck, wherein none of said apertures is disposed beneath said cavity.

6. The power head assembly of claim 1, further comprising:

a charger connector, interconnected with said second housing, that interconnects said first and second batteries with a battery charger;

a control circuit, disposed within said first housing, that controls the power to said motor; and

a key that is removably connectable to said control circuit, said key being disposed such that said key blocks said charger connector when said key is connected to said control circuit.

7. The power head assembly of claim 6, further comprising:

an aperture disposed in said first battery that receives said key.

8. The power head assembly of claim 6, wherein said key is positioned such that said key is removed when said second housing is removed.

9. The power head assembly of claim 1, further comprising:

mounting means for mounting said first housing to a deck of said grass cutting device; and

first, second and third apertures disposed in said mounting means, said apertures being disposed such that each of said apertures is about 4 inches from said shaft centerline in a radial direction, said first aperture being disposed at about 127 degrees in a counterclockwise direction with respect to a zero position when viewed from an end of said motor shaft, said second aperture being disposed at about 229 degrees in a counterclockwise direction with respect to said zero position when viewed from said shaft end, and said third aperture being disposed at about 337 degrees in a counterclockwise direction with respect to said zero position when viewed from said shaft end.

10. The power head assembly of claim 1, wherein said first housing is mounted to a deck of said grass cutting device, and wherein a portion of said motor is disposed below said deck.

11. The power head assembly of claim 1, further comprising:

a metal plate, disposed at a lower end of said first housing, that supports said motor.

12. The power head assembly of claim 11, wherein said metal plate includes a raised portion that tilts said motor.

13. The power head assembly of claim 1, further comprising:

means for tilting said motor shaft.

14. The power head assembly of claim 13, wherein said tilting means includes a metal plate having at least one raised portion that tilts one side of said motor.

15. The power head assembly of claim 13, wherein said tilting means includes means for making said shaft centerline non-perpendicular to a surface to which said motor is mounted.

16. The power head assembly of claim 1, wherein each of said batteries has a centerline that passes through said motor, and wherein said battery centerlines do not intersect said motor shaft centerline.

17. The power head assembly of claim 16, wherein said battery centerlines are collinear.

18. The power housing assembly of claim 1, wherein said first housing further comprises:

a first support that supports said first battery; and

a second support that supports said second battery.

19. A power head assembly for a cordless electric grass cutting device, comprising:

an electric motor having a rotatable shaft that includes a centerline;

a first housing, including

a motor receptacle that receives said electric motor;

means for mounting said first housing to a deck of said grass cutting device;

a first quick disconnect electrical terminal in circuit connection with said motor;

a second housing positionable adjacent said first housing, including

a first battery receptacle, disposed on a first side of said motor receptacle when said second housing is adjacent to said first housing, that receives a first battery;

a second battery receptacle, disposed on an opposite second side of said motor receptacle when said second housing is adjacent to said first housing, that receives a second battery; and

a second quick disconnect electrical terminal, in circuit connection with said first and second batteries, that engages said first electrical terminal.

20. The power head assembly of claim 19, further comprising:

mounting means for mounting said first housing to a deck of said grass cutting device; and

first, second and third apertures disposed such that each of said apertures is about 4 inches from said centerline of said shaft, and said apertures being disposed about said shaft centerline such that said first aperture is at about 127 degrees in a counterclockwise direction with respect to a zero position when viewed from an end of said motor shaft, said second aperture is at about 229 degrees in a counterclockwise direction with respect to said zero position when viewed from said shaft end, and said third aperture is at about 337 degrees in a clockwise direction with respect to said zero position when viewed from said shaft end.

21. The power head assembly of claim 19, wherein said first housing further comprises:

a first support that supports said first battery receptacle; and

a second support that supports said second battery receptacle.

22. The power head assembly of claim 19, wherein at least a portion of said motor is disposed below said deck.

23. The power head assembly of claim 19, wherein said second housing includes:

a handle near an upper end.

24. The power head assembly of claim 19, further comprising:

a control circuit, disposed in said first housing, that controls the power to said motor;

a charger connector, interconnected with said second housing, that interconnects said first and second batteries with a battery charger; and

a key that is removably connectable to said control circuit, said key being disposed such that said key blocks said charger connector when said key is connected to said control circuit.

25. The power head assembly of claim 24, wherein said key is disposed in an aperture in said first battery.

26. The power head assembly of claim 25, wherein said key is disposed such that said key is removed when said second housing is moved away from said first housing.

27. The power head assembly of claim 19, further comprising:

a bottom wall that supports said motor.

28. The power head assembly of claim 19, wherein each of said battery receptacles has a centerline that passes through said motor, and wherein said battery centerlines do not intersect said motor shaft centerline.

29. The power head assembly of claim 28, wherein said receptacle centerlines are collinear.

30. The power head assembly of claim 19, further comprising:

means for tilting said motor.

31. The power head assembly of claim 30, wherein said tilting means includes:

a metal plate having at least one standoff.

32. The power head assembly of claim 30, wherein said tilting means includes providing an end of said first housing with a greater height than an opposite end of said first housing.

33. A power head assembly for a cordless electric grass cutting device, comprising:

a battery that is removable from said device without the use of a tool;

a first housing having a battery receptacle that encloses at least a portion of said battery, said first housing having a first aperture therein;

a motor;

a second housing, disposed adjacent said first housing, that encloses at least a portion of said motor, said second housing having a second aperture therein that is aligned with said first aperture; and

a key having a prong that is removably disposed in said first aperture and in said second aperture.

34. The power head assembly of claim 33, wherein said key prong is disposed such that said prong is removed from said second aperture when said battery is removed from said device.

35. The power head assembly of claim 33, wherein said first housing and said battery are removable as a unit from the device without the use of a tool, said first housing having a first quick disconnect terminal, and wherein said second housing has a second quick disconnect terminal that engages said first quick disconnect terminal.

36. A power head assembly for a cordless electric grass cutting device, comprising:

a battery that is removable from said device without the use of a tool;

a first housing having a battery receptacle that encloses at least a portion of said battery, said first housing having a first aperture therein;

a motor;

a second housing, disposed adjacent said first housing, that encloses at least a portion of said motor, said second housing having a second aperture therein that is aligned with said first aperture; and

a removable key having a prong that first passes through said first aperture and then through said second aperture before said motor is operable.

37. The power head assembly of claim 36, wherein said key prong is disposed such that said prong is removed from said second aperture when said battery is removed from said device.

38. The power head assembly of claim 36, wherein said first housing and said battery are removable as a unit from the device without the use of a tool, said first housing having a first quick disconnect terminal, and wherein said second housing has a second quick disconnect terminal that engages said first quick disconnect terminal.