Safety mechanism for power tool and power tool incorporating such mechanism

• US 20050284647A1
• Filed: 08/09/2004
• Published: 12/29/2005
• Est. Priority Date: 08/09/2003
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Stones, Kevin
• Granted Patent: US 7,407,015 B2
• Time in Patent Office: Days
• US Class Current: 173/170
• CPC Class Codes: A01G 3/053 motor-driven
• CPC Class Codes: H01H 3/36 using belt, chain, or cord
• 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

A safety mechanism for a hedge trimmer is disclosed. Thumb catches 1032, 1048, together with corresponding locking members are initially biased downwardly relative to corresponding actuator levers 1010, 1014, as a result of which actuation of a motor of the hedge trimmer is prevented. This prevents inadvertent one-handed actuation of the hedge trimmer. In order to actuate the hedge trimmer, the user holds one of the actuator levers 1010, 1014 the corresponding thumb catch 1032 or 1048 upwardly, which causes movement of the other thumb catch towards its release position to allow pivotable movement of the actuator levers 1010, 1014 relative to a handle of the hedge trimmer. Movement of one of the actuator levers 1010, 1014 relative to the handle brings the lever 1018 into engagement with the electrical switch assembly 1008 to actuate the motor of the hedge trimmer. When the actuator levers 1010, 1014 are released, torsion springs urge the actuator levers 1010, 1014 and locking members outwardly relative to the handle housing 1004, as a result of which the locking members are urged into a locking position to prevent further actuation of actuator levers 1010, 1014 until the thumb catches 1032, 1048 have again been slid out of their locking position.

Claims

1. An actuator assembly for a power tool having at least one handle, a tool housing containing a motor, and a working member adapted to be actuated by means of the motor, the assembly comprising:

—

at least one actuator member adapted to be moved relative to a handle of the tool between a respective first position to actuate electrical switch means to actuate the motor, and a respective second position in which the electrical switch means is not actuated; and

at least one respective locking member mounted to the or each said actuator member, wherein the or each said locking member is movable relative to the corresponding said actuator member between a respective first position in which actuation of said actuator member is permitted and a respective second position in which actuation of the or each said actuator member is prevented.

2. An assembly according to claim 1, wherein at least one said locking member is adapted to abut at least one respective abutment on the corresponding said handle when in the second position thereof to prevent movement of the corresponding said actuator member relative to the handle to the respective first position of said actuator member.

3. An assembly according to claim 1, wherein at least one said locking member is slidable relative to the corresponding said actuator member between the respective first and second positions of said locking member.

4. An assembly according to claim 1, comprising a plurality of said actuator members.

5. An assembly according to claim 1, further comprising first biasing means for urging at least one said locking member towards the second position thereof.

6. An assembly according to claim 5, wherein said first biasing means comprises at least one spring.

7. An assembly according to claim 5, wherein the first biasing means comprises first interconnecting means for interconnecting a plurality of said locking members.

8. An assembly according to claim 7, wherein the first interconnecting means comprises at least one tension cable.

9. An assembly according to claim 1, further comprising second interconnection means for preventing at least one said actuator member from being in the first position thereof when a further said actuator member is in the first position thereof.

10. An assembly according to claim 9, wherein the second interconnection means comprises at least one interconnecting member pivotally attached adjacent end portions of a pair of adjacent said actuator members.

11. An assembly according to claim 10, wherein at least one said interconnection member is adapted to actuate said electrical switch means as a result of at least one corresponding actuator member moving to the first position thereof.

12. An assembly according to claim 1, further comprising second biasing means for urging at least one said actuator member towards a second position thereof.

13. An assembly according to claim 12, wherein said second biasing means comprises at least one torsion spring.

14. An actuator assembly for a power tool having at least one handle, a tool housing containing a motor, and a working member adapted to be actuated by means of the motor.

15. A handle assembly for a power tool, the handle assembly comprising a handle housing, electrical switch means for actuating an electric motor of the tool, and an actuator assembly, for actuating said electrical switch means.

16. A power tool comprising a handle assembly according to claim 15, a tool housing, a motor within the tool housing, and a working member adapted to be actuated by said motor.