Battery pack-operated hand-guided power tool with throttle lever

• US 8,353,362 B2
• Filed: 02/22/2010
• Issued: 01/15/2013
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Andreas STIHL AG & Company KG (Stihl Holding AG & Company KG)
• Original Assignee: Andreas STIHL AG & Company KG (Stihl Holding AG & Company KG)
• Inventors: Liebhard, Gernot, Hamersmit, Ante
• Primary Examiner(s): Nash, Brian D
• Application Number:
  US12/709,658
• Publication Number:
  US 20100218966A1
• Time in Patent Office: 1,058 Days
• Field of Search: 173/170, 173/217, 173/2
• US Class Current: 173/170
• CPC Class Codes: A01G 3/053 motor-driven
• CPC Class Codes: B25F 5/001 Gearings, speed selectors, clutches or the like specially adapted for rotary tools
• CPC Class Codes: H01H 2300/026 Application dead man switch: power must be interrupted on release of operating member

Abstract

A hand-held power tool has a device housing and at least one grip disposed on the device housing. An electric drive motor is arranged in the device housing for operating a working tool. A battery pack provides electric energy for operating the electric drive motor. An electronic control unit is connected to the electric drive motor and the battery pack. An operating element disposed on the grip controls the electric drive motor. An electric actuator is acted upon by the operating element and the output signal of the electric actuator is supplied to the electronic control unit. Electric energy is applied to the electric drive motor by the electronic control unit as a function of a position of the operating element, wherein in a first dead travel range of the operating element that adjoins an inoperative position of the operating element the supplied electric energy is zero.

Claims

1. A hand-held power tool comprising:

a device housing;

at least one grip disposed on said device housing;

an electric drive motor arranged in said device housing;

an output connected to said electric motor for operating a working tool;

a battery pack providing direct current as electric energy for operating said electric drive motor an electronic control unit that is connected through a power circuit to said electric drive motor and is further connected to said battery pack;

an operating element disposed on said at least one grip for controlling said electric drive motor;

an electric actuator acted upon by said operating element, wherein said electric actuator generates an output signal that is dependent on a position of said electric actuator, the position of said electric actuator dependent on a position of said operating element, wherein the output signal is supplied through a control line to said electronic control unit;

wherein said electronic control unit supplies to said electric drive motor the direct current of said battery pack as a pulse width-modulated signal sequence based on the position of said electric actuator;

wherein a period duration of the pulse-width modulated signal sequence is composed of a voltage signal with a signal duration and of a signal pause with a pause duration, wherein, with the period duration remaining the same, the signal duration is varied by said electronic control unit as a function of the position of said electric actuator so that the electric energy that is applied to said electric drive motor by said electronic control unit is applied as a function of the position of said operating element, wherein in a first dead travel range of said operating element that adjoins an inoperative position of said operating element the supplied electric energy is zero;

wherein upon passing from said first dead travel range to an adjoining second travel range, the pulse width of the signal sequence jumps from zero to a predetermined start value.

2. The power tool according to claim 1, wherein said first dead travel range of said operating element is approximately 30% to 60% of a total travel range.

3. The power tool according to claim 2, wherein said first dead travel range of said operating element is approximately 40% to 45% of said total travel range.

4. The power tool according to claim 1, wherein said operating element is pivotable about an axis of rotation and wherein said first dead travel range corresponds to a rotary angle of 0 to 10°

.

5. The power tool according to claim 4, wherein said first dead travel range corresponds to a rotary angle of up to 7°

.

6. The power tool according to claim 1, wherein the predetermined electric energy value is approximately 30% of a nominal power of said electric drive motor.

7. The power tool according to claim 1, wherein said electric drive motor is an electronically commutated motor.

8. The power tool according to claim 7, wherein control electronics of said electronically commutated motor are integrated into said electronic control unit.

9. The power tool according to claim 1, comprising a switch arranged on said at least one grip, wherein said switch is a component of a two-hand safety device.

10. The power tool according to claim 1, wherein said power circuit that supplies operating power comprises at least one mechanical switch.

11. The power tool according to claim 10, wherein said electronic control unit and a switching position of said at least one mechanical switch are matched to one another such that said at least one mechanical switch opens and/or closes when currentless.