IP Library Granted Patent US 7,816,796
Granted Patent B2
US 7,816,796 · App. 11/836,162 · Granted Oct 19, 2010

Hand-held power tool and method for operating a heating device of a hand-held power tool

Assignee: Andreas Stihl AG & Co. KG
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Quick Facts
Patent No.
US 7,816,796
App. No.
11/836,162
Granted
Oct 19, 2010
Kind
B2
Abstract

A hand-held power tool has a drive motor driving a tool and a generator. One or more heating devices having one or more heating elements are provided. The generator supplies the one or more heating devices with energy. A control device controls a power supplied to the one or more heating elements as a function of at least one operating parameter of the drive motor.

Claims (34)

1. A hand-held power tool comprising:

a drive motor,

a tool driven by said drive motor;

a generator driven by said drive motor, wherein a power provided by said generator increases as an engine speed of said drive motor increases;

one or more heating devices comprising one or more heating elements, wherein said generator supplies said one or more heating devices with energy;

a control device controlling a power supplied to at least one of said one or more heating elements as a function of said engine speed of said drive motor;

wherein the power supplied to said at least one heating element is reduced as a function of said engine speed relative to the power provided by said generator.

2. The power tool according to claim 1 , wherein said one or more heating devices have a temperature sensor for a temperature-dependent control of said power.

3. The power tool according to claim 2 , wherein said temperature sensor is an NTC resistor.

4. The power tool according to claim 2 , wherein said temperature sensor is arranged at a spacing from said one or more heating elements.

5. The power tool according to claim 1 , wherein said drive motor is an internal combustion engine comprising a carburetor and wherein one of said one or more heating devices is a carburetor heater.

6. The power tool according to claim 5 , wherein said one or more heating devices have a temperature sensor for a temperature-dependent control of said power and wherein said temperature sensor is connected to said carburetor by a contact surface providing a thermally conducting connection.

7. The power tool according to claim 1 , comprising at least one handle for guiding the power tool, wherein one of said one or more heating devices is a handle heater.

8. The power tool according to claim 1 , wherein said power increases with increasing engine speed of said drive motor.

9. The power tool according to claim 1 , wherein the power supplied to said at least one heating element is reduced above a limit value of said engine speed.

10. A hand-held power tool comprising:

a drive motor;

a tool driven by said drive motor;

a generator driven by said drive motor;

one or more heating devices comprising one or more heating elements, wherein said generator supplies said one or more heating devices with energy;

a control device controlling a power supplied to at least one of said one or more heating elements as a function of at least one operating parameter of said drive motor;

wherein said drive motor is an internal combustion engine comprising a carburetor and wherein one of said one or more heating devices is a carburetor heater;

wherein said one or more heating devices have a temperature sensor for a temperature-dependent control of said power and wherein said temperature sensor is connected to said carburetor by a contact surface providing a thermally conducting connection;

wherein said temperature sensor has a cover that thermally shields said temperature sensor except said contact surface.

11. The power tool according to claim 10 , wherein said cover is a plastic cap.

12. The power tool according to claim 10 , comprising a support wherein said control device and said temperature sensor are arranged on said support and wherein said cover is connected to said support by a snap-on connection.

13. A method for operating a heating device of a hand-held power tool comprising a drive motor, a tool driven by the drive motor, a generator driven by the drive motor, one or more heating devices each comprising one or more heating elements, wherein the generator supplies energy to the one or more heating devices; said method comprising the step of:

controlling a power supplied by a generator to at least one of the heating elements as a function of an engine speed of the drive motor and reducing the power supplied to the at least one heating element as a function of the engine speed relative to the power provided by the generator.

14. The method according to claim 13 , wherein, in the step of controlling, the power is reduced above a limit value.

15. The method according to claim 13 , wherein the engine speed is derived from a voltage signal of the generator.

16. The method according to claim 13 , wherein the at least one operating parameter is a temperature measured by a temperature sensor.

17. A method for operating a heating device of a hand-held power tool comprising a drive motor, a tool driven by the drive motor, a generator driven by the drive motor, one or more heating devices each comprising one or more heating elements, wherein the generator supplies energy to the one or more heating devices; said method comprising the step of:

controlling a power supplied by a generator to at least one of the heating elements as a function of at least one operating parameter of the drive motor, wherein, in the step of controlling, every other half wave of a voltage signal generated by the generator is blocked from being supplied to the at least one heating element when a limit value of the at least one operating parameter is surpassed.

18. The method according to claim 17 , wherein, in the step of controlling, phase control is used on the voltage signal generated by the generator.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 9, 2007
From: LEUFEN, HEINRICH; WALTER, ROLF; BERKENKAMP, FRIED
To: ANDREAS STIHL AG & CO. KG
Reel/Frame 019670/0210 →
Priority Claims (1)
DE 10 2006 037 572 · Aug 11, 2006 · national
Continuity (1)
Related Publication 20080036429A1 · Feb 14, 2008