Cam and clutch configuration for a power tool

• US 20050218185A1
• Filed: 03/31/2005
• Published: 10/06/2005
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Schell, Craig A., Gross, Paul, Berry, Alan, Kenney, James J.
• Granted Patent: US 8,123,099 B2
• Time in Patent Office: Days
• US Class Current: 227/133
• CPC Class Codes: B25C 1/06 operated by electric power

Abstract

A power tool with a flywheel, an activation arm, a driver, a cam and a clutch. The activation arm can have a first arm, a second arm, which can be pivotally mounted to the first arm, and a roller that can be coupled to the second arm. The driver can be disposed between the roller and the flywheel. The cam can be moveable in a predetermined direction for causing the activation arm to rotate about a pivot to drive the roller against the driver so that the driver frictionally engages the flywheel. The clutch can cooperate with the cam to inhibit the cam from moving in a direction opposite the predetermined direction in response to a reaction force that is applied by the driver onto the activation arm.

Claims

1. A power tool comprising:

a flywheel;

an activation arm having a first arm, a second arm pivotally mounted to the first arm, and a roller that is coupled to the second arm;

a driver disposed between the roller and the flywheel;

a cam that is movable in a predetermined direction for causing the activation arm to rotate about a pivot to drive the roller against the driver so that the driver frictionally engages the flywheel; and

a clutch that cooperates with the cam to inhibit the cam from moving in a direction opposite the predetermined direction in response to a reaction force that is applied by the driver onto the activation arm.

2. The power tool of claim 1, wherein the clutch includes a ground plate with a pair of inwardly tapered engagement surfaces that matingly engage a pair of engagement surfaces that are formed on the cam.

3. The power tool of claim 2, further comprising a structural backbone to which the ground plate is coupled.

4. The power tool of claim 3, wherein the structural backbone includes a clutch mount into which the ground plate is received.

5. The power tool of claim 4, wherein the ground plate includes a pair of outwardly projecting end walls and wherein fasteners that are threadably engaged to the structural backbone are employed to both drive the ground plate in a predetermined direction relative to the structural backbone and fixedly but removably couple the ground plate to the structural backbone.

6. The power tool of claim 1, wherein one of the clutch and the cam includes a set of ways and the other one of the clutch and the cam includes a way slot into which the set of ways is received, the ways and the way slot cooperating to guide the cam in the predetermined direction.

7. The power tool of claim 1, wherein the cam is moved in the predetermined direction by a linear actuator.

8. The power tool of claim 7, wherein the linear actuator is a solenoid.

9. The power tool of claim 1, wherein the cam includes a tapered cam surface and wherein the first arm carries a follower that is contacted by the tapered cam surface.

10. The power tool of claim 9, wherein the cam includes a member that is disposed on a side of the follower opposite the tapered cam surface and wherein contact between the member and the follower maintains the clutch in a disengaged condition so that the cam may be moved in the direction opposite the predetermined direction.

11. The power tool of claim 1, further comprising a nosepiece and a magazine assembly, the magazine assembly being operable for holding a plurality of fasteners and sequentially feeding the fasteners into the nosepiece where the driver may be reciprocated along the axis to drive a first one of the fasteners into a workpiece.

12. The power tool of claim 1, wherein the roller is mounted to a third arm that is pivotally mounted to the second arm.

13. The power tool of claim 12, wherein a spring biases the second arm about the first arm in a rotational direction that brings the roller relatively closer to the driver.

14. The power tool of claim 1, wherein the driver includes a cam profile with a ramped section that increases a force with which the driver is engaged to the flywheel.

15. A power tool comprising:

a structural backbone;

a flywheel mounted on the structural backbone;

an activation arm having a first arm, a second arm and a roller, the first arm being coupled to a follower, the second arm being pivotally mounted to the first arm, the roller being coupled to the second arm;

a pivot pivotally coupling the first arm to the structural backbone;

a driver disposed between the roller and the flywheel and movable along a translation axis between a retracted position and an extended position;

a cam having a cam surface that is engagable to the follower;

an actuator with a body and a member that is movable relative to the body along an actuation axis, the body being coupled to the structural backbone, the member being coupled to the cam such that the cam is movable along the actuation axis in a first direction and a second direction that is opposite the first direction; and

a ground plate coupled to the structural backbone;

wherein actuation of the power tool is at least partially accomplished through movement of the member in the first direction such that the cam surface contacts the follower and pivots the first arm about the pivot pin and the roller engages the driver against the flywheel to thereby transfer energy from the flywheel to the driver, and wherein a reaction force applied to the activation arm drives the cam into locking frictional engagement with the cam to the ground plate to thereby resist movement of the cam in the second direction.

16. The power tool of claim 15, wherein the ground plate includes a pair of tapered engagement surfaces and the cam includes a pair of mating engagement surfaces that engage the tapered engagement surfaces when the cam is in locking frictional engagement with the ground plate.

17. The power tool of claim 15, wherein the ground plate includes a pair of outwardly projecting end walls and wherein fasteners that are threadably engaged to the structural backbone are employed to both drive the ground plate in a predetermined direction relative to the structural backbone and fixedly but removably couple the ground plate to the structural backbone.

18. The power tool of claim 15, wherein one of the ground plate and the cam includes a set of ways and the other one of the ground plate and the cam includes a way slot into which the set of ways is received, the ways and the way slot cooperating to guide the cam along the actuation axis.

19. The power tool of claim 15, wherein the actuator is a solenoid.

20. The power tool of claim 15, wherein the cam includes a member that is disposed on a side of the follower opposite the tapered cam surface and wherein contact between the member and the follower maintains the cam and the ground plate in a disengaged condition so that the cam may be moved in the direction opposite the predetermined direction.

21. The power tool of claim 15, further comprising a nosepiece and a magazine assembly, the magazine assembly being operable for holding a plurality of fasteners and sequentially feeding the fasteners into the nosepiece where the driver may be reciprocated along the axis to drive a first one of the fasteners into a workpiece.

22. The power tool of claim 15, wherein the roller is mounted to a third arm that is pivotally mounted to the second arm.

23. The power tool of claim 15, wherein a spring biases the second arm about the first arm in a rotational direction that brings the roller relatively closer to the driver.

24. The power tool of claim 15, wherein the driver includes a cam profile with a ramped section that increases a force with which the driver is engaged to the flywheel.