Method for operating a hand-guided processing device, and hand-guided processing device

Patent metadata

Field	Value
Publication number	US-12337498-B2
Application number	US-202117154753-A
Country	US
Kind code	B2
Filing date	Jan 21, 2021
Priority date	Jan 22, 2020
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

A method is provided for operating a hand-guided processing device that has a rotating and/or circulating cutting tool, an electric motor drive system wherein the electric motor drive system is configured for generating a torque for driving the cutting tool, and a user-operable control element. The method automatically monitors whether a blocking criterion is fulfilled, wherein the blocking criterion is characteristic of a blocking of the cutting tool, and if the blocking criterion is fulfilled and the control element operated, automatically lowers the torque generated by the electric motor drive system, and temporally thereafter, automatically increases the torque generated by the electric motor drive system.

First claim

What is claimed is:

1. A method for operation of a hand-guided processing device, wherein the processing device comprises:
a rotating or circulating cutting tool;
an electric motor drive system, wherein:
the electric motor drive system is configured for generating a torque for driving the cutting tool;

a monitoring and control device; and
a user-operable control element configured to be user-adjustable,
wherein the method comprises the steps of:
a) using the monitoring and control device to automatically monitor whether a blocking criterion is fulfilled, wherein:
the blocking criterion is characteristic of a processing piece to be cut by the cutting tool causing movement of the cutting tool to be at least one of blocked or seized;

b) in response to the blocking criterion being fulfilled and the control element being operated, using the monitoring and control device to automatically lower the torque generated by the electric motor drive system that drives the cutting tool while the blocking criterion is fulfilled, and subsequently, automatically increase the torque generated by the electric motor drive system that drives the cutting tool; and
c) in response to the blocking criterion not being fulfilled and the control element is operated, automatically controlling or regulating the torque generated by the electric motor drive system for reaching a nominal rotational speed of at least one of the electric motor drive system or the cutting tool, where the nominal rotational speed is based on a setting associated with the user-operable control element set by a user, wherein:
a non-blocking rotational speed lower limit value for the nominal rotational speed is at least twice as great as greater than a blocking rotational speed lower limit value;

wherein the processing device is at least one of a gardening, forestry, or construction processing device, and
wherein the blocking criterion is that while the control element is operated, the generated torque driving the cutting tool is greater than zero, and current effecting the torque is greater than zero, at least one of a rotational speed of the electric motor drive system is less than or equal to the blocking rotational speed lower limit value or a rotational speed of the cutting tool is less than or equal to the blocking rotational speed lower limit value.

2. The method according to claim 1 , wherein at least one of:
the processing device is a chain saw; or
the cutting tool comprises a saw chain.

3. The method according to claim 1 , wherein:
the electric motor drive system and the cutting tool are coupled together without a clutch.

4. The method according to claim 1 ,
wherein step b) is repeated automatically until a repetition number limit value is reached.

5. The method according to claim 4 , wherein at least one of:
the automatic lowering is performed with a lowering duration of at least 1 ms and/or at most 2 s, or
the automatic increasing is performed with an increase duration of at least 1 ms and/or at most 2 s, or
the automatic increasing is performed after a pause duration of at least 1 ms and/or at most 2 s after the automatic lowering, or
on repetition of step b), the automatic lowering is carried out after a holding duration of at least 0 ms and/or at most 2 s after the automatic increasing.

6. The method according to claim 4 , wherein the method further comprises the steps of:
detecting a temperature of the electric motor drive system and/or of an accumulator electrically connected to the processing device, wherein
the repetition number limit value, the non-blocking upper limit value and/or the blocking upper limit value is/are adjusted dependent on the detected temperature.

7. The method according to claim 1 , further comprising the step of:
c) in response to the blocking criterion not being fulfilled and the control element is operated, automatically controlling or regulating the torque generated by the electric motor drive system for reaching a nominal rotational speed of the electric motor drive system and/or the cutting tool.

8. The method according to claim 7 ,
wherein step b) further comprises: in response to the control element being set at least in a starting position to at least 10%, automatically lowering the torque generated by the electric motor drive system, and subsequently, automatically increasing the torque generated by the electric motor drive system independently of the setting of the control element in at least the starting position.

9. The method according to claim 7 , wherein at least one of:
in step c), an automatic increasing of the generated torque or a current effecting the torque is limited to a non-blocking upper limit value, and wherein
in step b), the torque or the current is lowered from the non-blocking upper limit value, or
in step b), the automatic increasing of the generated torque or current is limited to a blocking upper limit value, or
in step b), the automatic lowering of the generated torque or current is limited to a blocking lower limit value greater than zero, wherein
the blocking lower limit value is at least 0.1 times and/or at most 0.25 times the blocking upper limit value.

10. The method according to claim 9 , wherein
step b) is repeated automatically until a repetition number limit value is reached, wherein
the blocking upper limit value is reduced dependent on a number of repetitions of step b).

11. The method according to any of claim 9 ,
wherein the processing device is configured for electrical connection to various types of accumulators, wherein the various types of accumulators have different maximum current values, wherein the processing device is electrically connected to one of the various types of accumulators,
wherein the method further comprises the step of:
detecting the type of the electrically connected accumulator and determining the maximum current value based on the detected type, and/or detecting the maximum current value of the electrically connected accumulator, and
wherein the non-blocking upper limit value and/or the blocking upper limit value is/are adjusted dependent on the maximum current value.

12. The method according to claim 1 ,
wherein step b) further comprises: outputting a user-perceptible blocking signal.

13. The method of claim 1 , wherein the blocking rotational speed lower limit value is zero.

14. A hand-guided processing device, comprising;
a rotating or circulating cutting tool;
an electric motor drive system, wherein the electric motor drive system is configured for generating a torque for driving the cutting tool;
a user-operable control element configured to be user-adjustable; and
a monitoring and control device, wherein the monitoring and control device is operatively configured to:
automatically monitor whether a blocking criterion is fulfilled, wherein the blocking criterion is characteristic of a processing piece to be cut by the cutting tool causing movement of the cutting tool to be at least one of blocked or seized, and
in response to the blocking criterion being fulfilled and the control element being operated, automatically lower the torque generated by the electric motor drive system that drives the cutting tool while the blocking criterion is fulfilled, and subsequently, automatically increase the torque generated by the electric motor drive system that drives the cutting tool,
in response to the blocking criterion not being fulfilled and the control element is operated, automatically control or regulate the torque generated by the electric motor drive system for reaching a nominal rotational speed of at least

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Haas Alexander
• Mueller Edgar
• Nemec Christian

Classifications

• H02P6/12

  Monitoring commutation; Providing indication of commutation failure · CPC title

• H02P6/08

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title

• B25F5/001

  Gearings, speed selectors, clutches or the like specially adapted for rotary tools · CPC title

• H02P29/68

  based on the temperature of a drive component or a semiconductor component · CPC title

• B28D7/005

  Devices for the automatic drive or the program control of the machines · CPC title