Electro-mechanical interlock and module system for lawn mower or other electrical device

• US 5,085,043 A
• Filed: 06/01/1990
• Issued: 02/04/1992
• Est. Priority Date: 06/01/1990
• Status: Expired

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Shaver, David M., Dyke, Colin, Hess, Kristoffer A.
• Primary Examiner(s): Britts, Ramon S.
• Assistant Examiner(s): MELIUS, TERRY L
• Application Number:
  US07/532,038
• Time in Patent Office: 613 Days
• Field of Search: 56/10.5, 56/10.8, 56/16.7, 56/17.5, 56/320.1, 56/DIG. 24
• US Class Current: 56/10.5
• CPC Class Codes: A01D 34/828 Safety devices
• CPC Class Codes: A01D 69/02 electric
• CPC Class Codes: H01H 27/00 Switches operated by a removable member, e.g. key, plug or plate; Switches operated by setting members according to a single predetermined combination out of several possible settings combined with plug-and-socket connectors H01R13/70; with current-carrying plug H01R31/08
• 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

Abstract

An electro-mechanical interlock and module system for an electrically powered device such as a cordless, electric lawn mower that includes a normally open interlock switch for controlling the enabling of the power circuit for the lawn mower. A key member is adapted for insertion into a specially configured opening in the mower housing to actuate and close the interlock switch. With the interlock switch closed, energization of the motor is controlled by a separate handle-mounted ON/OFF switch in a conventional manner. In addition, a modular assembly technique is disclosed which facilitates ease of manufacturing while assuring proper alignment between the various components of the interlock system.

Claims

1. An electrically powered lawn mower comprising a mower deck, an electric motor mounted to the mower deck for rotatably driving a cutting blade located beneath the mower deck, a handle connected to the mower deck, a shroud covering the motor, a power circuit including a rechargeable battery for providing electrical power to the motor and an electrical connector adapted for connection to an external source of electrical current for charging said battery, a manually operable electric switch mounted to the handle and connected in said power circuit and having ON and OFF positions for controlling the application of electrical power to the motor, and an interlock system for controlling the enabling of said power circuit, including

an interlock switch connected in said power circuit and having an actuator for controlling the state of said interlock switch;

said interlock switch having a first normal state for disabling said power circuit and a second state for enabling said power circuit, such that when said interlock switch is in said first state the electric motor cannot be energized by said power circuit regardless of the position of said handle mounted switch, and when said interlock switch is in said second state the electric motor is energizable by said power circuit in accordance with the position of said handle mounted switch;

means for mounting said interlock switch within said shroud adjacent a specially configured first opening in said shroud such that the actuator of said interlock switch is accessible through said first opening; and

a key member configured for insertion into said first opening in said shroud and including actuating means for engaging said actuator of said interlock switch and causing said interlock switch to switch from said first state to said second state to thereby enable said power circuit when said key member is fully inserted into said first opening in said shroud and further including means for blocking access to said electrical connector when said key member is fully inserted into said first opening in said shroud to thereby prevent said battery from being charged when said interlock switch is in said second state.

2. The lawn mower of claim 1 wherein said interlock switch is mounted to a bracket member that is joined to said shroud by alignment means for aligning the actuator of said interlock switch with said first opening in said shroud.

3. The lawn mower of claim 2 wherein said power circuit is contained on a printed circuit board that is also mounted to said bracket member.

4. The lawn mower of claim 2 wherein said key member actuating means comprises a stem portion having a cam surface thereon for engaging the actuator of said interlock switch.

5. The lawn mower of claim 4 wherein said bracket member has a second opening formed therein that is aligned with said first opening in said shroud and configured to conform to the shape of said stem portion for receiving said stem portion, said second opening being located adjacent said actuator when said interlock switch is mounted on said bracket member for aligning said cam surface with said actuator when said stem portion is inserted into said second opening.

6. The lawn mower of claim 5 wherein said stem portion has a distal end and said cam surface is positioned on said stem portion such that the distal end of said stem portion enters said second opening in said bracket member before said cam surface engages said actuator.

7. The lawn mower of claim 1 wherein said key member is further configured to be flush with the surface of said shroud when fully inserted into said first opening in said shroud.

8. The lawn mower of claim 1 further including means for retaining said key member in said fully inserted position.

9. The lawn mower of claim 1 wherein said bracket member is located between said battery and said shroud and further includes coupling means for loosely connecting said bracket member to said battery.

10. An electrically powered device having an electric motor, a housing for said electric motor, a power circuit including a rechargeable battery for providing electrical power to the motor and an electrical connector adapted for connection to an external source of electrical current for charging the battery, and an interlock system comprising:

an interlock switch connected in said power circuit and having an actuator for controlling the state of said interlock switch, said interlock switch having a first normal state for disabling said power circuit and a second state for enabling said power circuit;

support and alignment means for positioning said interlock switch within said housing adjacent a specially configured first opening in such housing such that the actuator of said interlock switch is aligned with said first opening, including a support bracket having mounting means for mounting said interlock switch in a predetermined position on said support bracket and alignment means for fixing the position of said support bracket relative to said housing; and

a key member configured for insertion into said first opening in said housing and including actuating for engaging said actuator of said interlock switch and causing said interlock switch to switch from said first state to said second state to thereby enable said power circuit when said key member is fully inserted into said first opening in said housing and further including means for blocking access to said electrical connector when said key member is fully inserted into said first opening in said housing to thereby prevent said battery from being charged when said interlock switch is in said second state.

11. The device of claim 10 wherein said support bracket further includes a second opening aligned with said first opening in said housing and configured to conform to the shape of said key member actuating means for receiving said actuating means, said second opening being located adjacent said actuator when said interlock switch is mounted on said support bracket for aligning said actuating means with said actuator.

12. The device of claim 10 wherein said power circuit includes a manually operable electric switch having ON and OFF positions for controlling the application of electrical power to the motor when said interlock switch is in said second state.

13. The device of claim 12 wherein said power circuit is contained on a printed circuit board that is also mounted to said support bracket.

14. The device of claim 11 wherein said key member actuating means comprises a stem portion having a cam surface formed thereon for engaging the actuator of said interlock switch.

15. The device of claim 14 wherein said stem portion has a distal end and said cam surface is positioned on said stem portion such that the distal end of said stem portion enters said second opening in said support bracket before said cam surface engages said actuator.

16. The device of claim 10 wherein said key member is further configured to be flush with the surface of said housing when fully inserted into said first opening in said housing.

17. The device of claim 10 further including means for retaining said key member in said fully inserted position.

18. An interlock system for an electrically powered device having an electric motor, a housing for said electric motor, a power circuit including a rechargeable battery for providing electrical power to the motor and an electrical connector adapted for connection to an external source of electrical current for charging the battery, and a first manually operable electric switch connected in said power circuit and having ON and OFF positions for controlling the application of electrical power to the motor, comprising:

an interlock switch connected in said power circuit and having an actuator for controlling the state of said interlock switch;

said interlock switch having a first normal state for disabling said power circuit and a second state for enabling said power circuit, such that when said interlock switch is in said first state the electric motor cannot be energized by said power circuit regardless of the position of said first electric switch, and when said interlock switch is in said second state the electric motor is energizable by said power circuit in accordance with the position of said first electric switch;

means for mounting said interlock switch within said housing adjacent a specially configured opening in such housing such that the actuator of said interlock switch is accessible through said opening; and

a key member configured for insertion into said opening in said housing and including actuating means for engaging said actuating of said interlock switch and causing said interlock switch to switch from said first state to said second state to thereby enable said power circuit and further including means for blocking access to said electrical connector when said key member is fully inserted into said opening in said housing to thereby prevent said battery from being charged when said interlock switch is in said second state.

19. A cordless, electric lawn mower comprising a mower deck, an electric motor mounted to the mower deck for rotatably driving a cutting blade located beneath the mower deck, a rechargeable battery for providing electrical power to the motor, a handle connected to the mower deck, a shroud covering the motor and battery, a power circuit for providing electrical power to the motor, a manually operable electric switch mounted to the handle and connected in said power circuit and having ON and OFF positions for controlling the application of electrical power to the motor, an electrical connector adapted for connection to an external source of electrical current for charging the battery, and an interlock system for controlling the enabling of said power circuit, including

an interlock switch connected in said power circuit and having an actuator for controlling the state of said interlock switch;

said interlock switch having a first normal state for disabling said power circuit and a second state for enabling said power circuit, such that when said interlock switch is in said first state the electric motor cannot be energized by said power circuit regardless of the position of said handle mounted switch, and when said interlock switch is in said second state the electric motor is energizable by said power circuit in accordance with the position of said handle mounted switch;

means for mounting said interlock switch within said shroud adjacent a specially configured first opening in said shroud such that the actuator of said interlock switch is accessible through said first opening, including a bracket member having mounting means for mounting said interlock switch in a predetermined position thereon and alignment means for coupling said bracket member to said shroud to fix the position of said bracket member relative to said shroud; and

a key member having a stem portion configured for insertion into said first opening in said shroud and including actuating means on said stem portion for engaging said actuator of said interlock switch and causing said interlock switch to switch from said first state to said second state to thereby enable said power circuit when said key member is fully inserted into said first opening in said shroud, and further including means for blocking access to said electrical connector when said key member is fully inserted into said first opening in said shroud to thereby prevent the battery from being charged when said power circuit is enabled.

20. The cordless lawn mower of claim 19 wherein said key member is further configured to be flush with the surface of said shroud when fully inserted into said first opening in said shroud.

21. The cordless lawn mower of claim 19 wherein said actuating means comprises a cam surface on said stem portion.

22. The cordless lawn mower of claim 21 wherein said bracket member has a second opening formed therein that is aligned with said first opening in said shroud and configured to conform to the shape of said stem portion for receiving said stem portion, said second opening being located adjacent said actuator when said interlock switch is mounted on said bracket member for aligning said cam surface with said actuator when said stem portion is inserted into said second opening.

23. The cordless lawn mower of claim 19 wherein said stem portion has a distal end and said cam surface is positioned on said stem portion such that the distal end of said stem portion enters said second opening in said bracket member before said cam surface engages said actuator.

24. The cordless lawn mower of claim 19 wherein said power circuit is contained on a printed circuit board that is also

25. The cordless lawn mower of claim 19 wherein said bracket member further includes coupling means for loosely fastening said bracket member to said battery.

26. The cordless lawn mower of claim 25 wherein said battery is secured to said mower deck by a strap that extends over the battery and further wherein said coupling means comprises a resilient tab member that is adapted to fit under said strap and loosely fasten said bracket member to said battery.