Starting device for starting a combustion engine and handheld work apparatus having said starting device

Patent metadata

Field	Value
Publication number	US-10954910-B2
Application number	US-201916356861-A
Country	US
Kind code	B2
Filing date	Mar 18, 2019
Priority date	Mar 16, 2018
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A starting device for a combustion engine includes a housing relative to which a rope pulley, a spring housing and an entrainer can rotate about a rotation axis. A coupling unit produces a rotationally-fixed connection between the rope pulley and the spring housing in response to a rotational movement of the rope pulley in a starting direction. The spring housing has a spring receiving space for a tension spring and is connected to an entrainer by the spring. The coupling unit has a first coupling element and a second coupling element, which interact at a contact location which is at a spacing (d) to the rotation axis and is at least as large as the maximum spacing (c) of the tension spring to the rotation axis.

First claim

What is claimed is:

1. A starting device for starting a combustion engine, the starting device comprising:
a starter housing defining a rotation axis;
a rope pulley, a spring housing and an entrainer each being rotatably mounted so as to rotate about said rotation axis relative to said starter housing;
said rope pulley being rotatable in a starting direction about said rotation axis;
a return spring mounted between said starter housing and said rope pulley so as to cause said return spring to become tensioned about said rotation axis in response to a rotational movement of said rope pulley in said starting direction;
a first coupling unit configured to establish a rotation-fixed connection between said rope pulley and said spring housing in response to a rotational movement of said rope pulley in said starting direction;
said first coupling unit being further configured to act as a freewheel between said rope pulley and said spring housing in response to rotational movement of said rope pulley in a second direction opposite to said starting direction;
a tension spring;
said spring housing having an outer periphery and defining a spring receptacle for accommodating said tension spring therein;
said spring housing being connected to said entrainer via said tension spring;
a second coupling unit arranged on said outer periphery of said spring housing;
said second coupling unit being configured to act as a freewheel between said spring housing and said starter housing in response to a rotational movement of said rope pulley in said starting direction and to prevent a rotational movement of said spring housing relative to said starter housing in said second direction;
said entrainer being provided for coupling said starting device to a motor shaft of said combustion engine;
said first coupling unit including at least one first coupling element and at least one second coupling element;
said at least one first coupling element and said at least one second coupling element coacting at least at one first contact location when establishing said rotation-fixed connection; and,
said at least one first contact location being at a distance (e) to said rotation axis which is at least as large as a maximum distance (c) of said tension spring to said rotation axis.

2. The starting device of claim 1 , wherein said first coupling unit and said tension spring mutually overlap in axial direction of said rotation axis.

3. The starting device of claim 1 , wherein said rope pulley has a concave inner peripheral surface; one of two coacting coupling elements of said first coupling unit is arranged on said spring housing; and, the other one of the two coacting coupling elements of said first coupling unit is arranged on said concave inner peripheral surface of said rope pulley.

4. The starting device of claim 1 , wherein said second coupling unit includes at least one first coupling element and at least one second coupling element; and, said at least one first coupling element of said second coupling unit and said at least one second coupling element of said second coupling unit coact at least at one second contact location when preventing a rotational movement of said spring housing in the second direction opposite to said starting direction.

5. The starting device of claim 4 , wherein said at least one second contact location is at a distance (d) to said rotation axis; and, said distance (d) is at least as large as said maximum distance (c) of said tension spring to said rotation axis.

6. The starting device of claim 4 , wherein said at least one second contact location is at a distance (d) to said rotation axis; said entrainer has a largest distance (g) to said rotation axis; and, said largest distance (g) is less than said distance (e) of said at least one first contact location to said rotation axis and less than said distance (d) of said at least one second contact location to said rotation axis.

7. The starting device of claim 4 , wherein said at least one first coupling element of said first coupling unit and said at least one coupling element of said second coupling unit are respective detents; said at least one second coupling element of said first coupling unit and said at least one second coupling element of said second coupling unit are respective catch cams; and, said at least one detent of said one coupling unit and said at least one catch cam of said other coupling unit are arranged on said spring housing.

8. The starting device of claim 4 , wherein said first contact location of said first coupling unit is arranged in a first axial section of said starting device and said second contact location of said second coupling unit is in a second section of said starting device; and, said first axial section and said second axial section are non-overlapping in the direction of said rotation axis.

9. The starting device of claim 1 , wherein at least one coupling element mounted on said spring housing is a detent and the mounting location of said at least one detent mounted on said spring housing is arranged radially outside of said spring receptacle referred to the rotation axis.

10. The starting device of claim 1 , wherein said first coupling unit and said second coupling unit mutually overlap in a radial direction of said rotation axis.

11. The starting device of claim 1 , wherein said spring housing and said rope pulley mutually overlap in the axial direction of said rotation axis.

12. The starting device of claim 1 , wherein said spring housing has a width (b) measured in the direction of said rotation axis; said rope pulley has a recess into which said spring housing projects; and, said rope pulley and said spring housing conjointly define a mutual overlapment which amounts to at least 25% of said width (b) of said spring housing.

13. The starting device of claim 1 , wherein said spring housing has a bearing dome for journaling said spring housing on a bearing lug of said starter housing; and, said bearing dome projects into said spring receptacle of said spring housing.

14. The starting device of claim 13 , wherein said entrainer overlaps the bearing dome of said spring housing in axial direction of the rotation axis.

15. The starting device of claim 1 , wherein at least one of said first and second coupling units has a single spring and has at least two first coupling elements charged by said single spring.

16. The starting device of claim 15 , wherein said single spring has a form of a ring segment; and, said single spring is arranged so as to charge said at least two first coupling elements in a radial direction toward said rotation axis.

17. A work apparatus comprising:
a combustion engine having a crankshaft;
a starting device for starting said combustion engine; and, said starting device including:
a starter housing defining a rotation axis;
a rope pulley, a spring housing and an entrainer each being rotatably mounted so as to rotate about said rotation axis relative to said starter housing;
said rope pulley being rotatable in a starting direction about said rotation axis;
a return spring mounted between said starter housing and said rope pulley so as to cause said return spring to become tensioned about said rotation axis in response to a rotational movement of said rope pulley in said starting direction;
a first coupling unit configured to establish a rotation-fixed connection between said rope pulley and said spring housing in response to a rotational movement of said rope pulley in said starting direction;
said first coupling unit being further configured to act

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Densborn Gerd
• Schliemann Harald

Classifications

• F02N15/027

  of the pawl type · CPC title

• F16D41/12

  with hinged pawl co-operating with teeth, cogs, or the like (F16D41/02, F16D41/24 take precedence) · CPC title

• F02N15/006

  Assembling or mounting of starting devices · CPC title

• A01G20/47

  Vacuum or blower devices · CPC title

• F02N3/02 Primary

  having pull-cords · CPC title