Method for sizing a motor for a power tool

• US 20050218186A1
• 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: Forster, Michael
• Granted Patent: US 7,322,506 B2
• Time in Patent Office: Days
• US Class Current: 227/133
• CPC Class Codes: B25C 1/06 operated by electric power

Abstract

A tool with a motor assembly and a driver. The motor assembly can include a flywheel that is driven by an electric motor. The driver can be selectively engaged by an edge of the flywheel to transmit energy therebetween to cause the driver to translate along an axis. The electric motor has a ke value that is between about 0.85 to about 0.55. A method for sizing a motor for a power tool is also provided.

Claims

1. A tool comprising:

a motor assembly with a flywheel that is driven by an electric motor; and

a driver that is selectively engagable with an edge of the flywheel to transmit energy therebetween to cause the driver to translate along an axis;

wherein the electric motor has a ke value that is between about 0.85 to about 0.55.

2. The tool of claim 1, wherein the ke value is between about 0.80 to about 0.65.

3. The tool of claim 2, wherein the ke value is between about 0.75 to about 0.70.

4. The tool of claim 1, wherein the motor assembly includes a roller that is movable between an unactuated position and an actuated position, wherein positioning of the roller in the actuated position drives the driver into the edge of the flywheel.

5. The tool of claim 1, further comprising a nosepiece and a magazine assembly, the magazine assembly being configured to hold a plurality of fasteners and dispense a first one of the fasteners into the nosepiece in-line with the axis along which the driver translates.

6. The tool of claim 1, wherein rotary power is transmitted from the electric motor to the flywheel via a belt drive.

7. The tool of claim 1, further comprising a battery, the battery providing a source of power for operating the electric motor.

8. The tool of claim 7, wherein the battery is coupled to a switching power supply and the electric motor is coupled to the switching power supply.

9. A method for sizing an electric motor for use in a hand-held tool having a power source with a motor and a flywheel, the electric motor being operable for driving the flywheel, the method comprising:

determining an inertia of the power source at a given rotational speed; and

sizing the electric motor so that the electric motor has a ke value of about 0.85 to about 0.55 when the inertia of the power source is driven at the given rotational speed.

10. The method of claim 9, wherein the ke value of the electric motor is between about 0.80 to about 0.65 when the inertia of the power source is driven at the given rotational speed.

11. The method of claim 10, wherein the ke value of the electric motor is between about 0.75 to about 0.70 when the inertia of the power source is driven at the given rotational speed.

12. A tool comprising:

a housing defining an internal cavity;

a backbone attached to the housing and at least partially disposed in the internal cavity; and

a drive motor assembly having a driver and a power source, the driver having an engagement surface, the power source being mounted on the backbone and including an electric motor, a flywheel driven by the electric motor and a roller, the roller being movable between an unactuated position and an actuated position, wherein placement of the roller in the actuated position forces the engagement surface of the driver into contact with a rotating edge of the flywheel to thereby transfer energy to the driver to cause the driver to translate along an axis;

wherein the electric motor has a ke value that is between about 0.85 to about 0.55.

13. The tool of claim 12, wherein the ke value is between about 0.80 to about 0.65.

14. The tool of claim 13, wherein the ke value is between about 0.75 to about 0.70.

15. The tool of claim 12, further comprising a nosepiece and a magazine assembly, the magazine assembly being configured to hold a plurality of fasteners and dispense a first one of the fasteners into the nosepiece in-line with the axis along which the driver translates.

16. The tool of claim 12, wherein rotary power is transmitted from the electric motor to the flywheel via a belt drive.

17. The tool of claim 12, further comprising a battery, the battery providing a source of power for operating the electric motor.

18. The tool of claim 17, wherein the battery is coupled to a switching power supply and the electric motor is coupled to the switching power supply.