Starter device, pulley assembly for a starter device, and connecting spring for a pulley assembly

Patent metadata

Field	Value
Publication number	US-11359591-B2
Application number	US-202016813871-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Mar 12, 2019
Publication date	Jun 14, 2022
Grant date	Jun 14, 2022

Abstract

A pulley assembly for a starter device for starting an internal combustion engine of a hand-guided power tool has a pulley with an axis of rotation extending in axial direction. A circumferential side of the pulley is positioned outwardly in radial direction relative to the axis of rotation. A circumferential recess is arranged at the circumferential side and accommodates a starter rope. The pulley is provided with a spring receptacle. A connecting spring is disposed in the spring receptacle and has a first end fixedly connected to the pulley. The spring receptacle and the recess overlap each other, viewed in the axial direction and viewed in the radial direction. A starter device is provided with the pulley assembly and a second end of the connecting spring is fixedly connected to a coupling device of the starter device that couples the pulley to the crankshaft of the combustion engine.

First claim

What is claimed is:

1. A pulley assembly for a starter device for starting an internal combustion engine of a hand-guided power tool, the pulley assembly comprising:
a pulley comprising an axis of rotation extending in an axial direction and further comprising a circumferential side, the circumferential side positioned outwardly in a radial direction relative to the axis of rotation;
the pulley comprising a circumferential recess arranged at the circumferential side and configured to accommodate a starter rope, wherein the circumferential recess extends precisely only once about the axis of rotation;
the pulley comprising a spring receptacle;
a connecting spring disposed in the spring receptacle and comprising a first end fixedly connected to the pulley;
the spring receptacle and the circumferential recess overlapping each other, viewed in the axial direction and viewed in the radial direction.

2. A pulley assembly for a starter device for starting an internal combustion engine of a hand-guided power tool, the pulley assembly comprising:
a pulley comprising an axis of rotation extending in an axial direction and further comprising a circumferential side, the circumferential side positioned outwardly in a radial direction relative to the axis of rotation;
the pulley comprising a circumferential recess arranged at the circumferential side and configured to accommodate a starter rope;
the pulley comprising a spring receptacle;
a connecting spring disposed in the spring receptacle and comprising a first end fixedly connected to the pulley;
the spring receptacle and the circumferential recess overlapping each other, viewed in the axial direction and viewed in the radial direction;
wherein the spring receptacle comprises a spring chamber and a hooking region configured to connect the connecting spring to the pulley, wherein the hooking region and the circumferential recess are arranged at least partially adjacent to each other in the axial direction;
wherein, viewed in the axial direction, the spring receptacle overlaps the circumferential recess exclusively with the hooking region.

3. The pulley assembly according to claim 2 , wherein the hooking region has a width measured in the axial direction, wherein the spring chamber has a width measured in the axial direction, wherein the width of the hooking region amounts to less than 100% of the width of the spring chamber.

4. The pulley assembly according to claim 3 , wherein the pulley comprises a maximum width measured in the axial direction and wherein the circumferential recess has a width, measured at the circumferential side of the pulley in the axial direction, that amounts to at least 15% of the maximum width of the pulley.

5. The pulley assembly according to claim 2 , wherein the first end of the connecting spring is hooked in the hooking region to the pulley, wherein the connecting spring comprises a maximum width measured in the axial direction and wherein the first end of the connecting spring comprises a width measured in the axial direction that amounts to less than 100% of the maximum width of the connecting spring.

6. The pulley assembly according to claim 5 , wherein the first end of the connecting spring is narrower than the maximum width of the connecting spring in an angle range of at least 5° in a circumferential direction about the axis of rotation.

7. The pulley assembly according to claim 1 , wherein the pulley comprises an air guiding contour at the circumferential side.

8. The pulley assembly according to claim 7 , wherein the air guiding contour is concave in a section view along the axis of rotation.

9. The pulley assembly according to claim 1 , wherein the connecting spring is a spiral spring.

10. The pulley assembly according to claim 1 , wherein the spring receptacle comprises a spring chamber, wherein the spring chamber comprises a rear wall, and wherein the connecting spring comprises a spacing relative to the rear wall that is measured in the axial direction and amounts to less than 25% of a maximum width of the connecting spring.

11. A pulley assembly for a starter device for starting an internal combustion engine of a hand-guided power tool, the pulley assembly comprising:
a pulley comprising an axis of rotation extending in an axial direction and further comprising a circumferential side, the circumferential side positioned outwardly in a radial direction relative to the axis of rotation;
the pulley comprising a circumferential recess arranged at the circumferential side and configured to accommodate a starter rope;
the pulley comprising a spring receptacle;
a connecting spring disposed in the spring receptacle and comprising a first end fixedly connected to the pulley;
the spring receptacle and the circumferential recess overlapping each other, viewed in the axial direction and viewed in the radial direction;
wherein the spring receptacle comprises a spring chamber, wherein the spring chamber comprises a rear wall, wherein the rear wall of the spring chamber comprises an outer side facing away from the connecting spring, wherein the spring chamber comprises an opening configured to enable insertion of the connecting spring into the spring chamber, wherein the pulley comprises a base body comprising a base body width measured in the axial direction from the outer side of the rear wall all the way to the opening, and wherein a maximum width of the connecting spring amounts to at least 80% of the base body width.

12. A starter device comprising a pulley assembly according to claim 1 , wherein the starter device comprises a coupling device configured to connect the pulley of the pulley assembly with a crankshaft of the internal combustion engine, wherein the connecting spring of the pulley assembly comprises a second end fixedly connected to the coupling device.

13. The starter device according to claim 12 , wherein the coupling device is a follower.

14. The starter device according to claim 13 , wherein the spring receptacle of the pulley of the pulley assembly comprises a spring chamber and wherein the follower completely covers the spring chamber in the axial direction of the pulley.

15. The starter device according to claim 12 , wherein the coupling device comprises coupling elements configured to couple the starter device with the crankshaft of the internal combustion engine, wherein the coupling device comprises an air guiding collar, wherein the air guiding collar is arranged on a side of the coupling device facing away from the connecting spring, and wherein the air guiding collar is arranged radially outwardly relative to the coupling elements.

16. The starter device according to claim 15 , wherein the air guiding collar, in a section view along the axis of rotation of the pulley, comprises at least one conical section.

17. The pulley assembly according to claim 1 , wherein the pulley assembly is configured to accommodate in the circumferential recess a plurality of windings of the starter rope.

18. The pulley assembly according to claim 1 , wherein the circumferential recess has closed annular shape extending about the axis of rotation.

Assignees

• Stihl Ag & Co Kg Andreas

Inventors

• Nefzger Markus
• Karrar Carel

Classifications

• F02N5/02 Primary

  of spring type · CPC title

• F16H55/36

  Pulleys (with features essential for adjustment F16H55/52) · CPC title

• F02N3/02 Primary

  having pull-cords · CPC title