# US 10,309,362 B2 · Starter device for an internal combustion engine and handheld work apparatus having an internal combustion engine and said starter device

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- Number: US 10,309,362 B2
- Document ID: US10309362B2
- Status: Granted
- Kind: B2
- Application number: 15/011,258
- Filed: 2016-01-29
- Published: 2016-08-04
- Granted: 2019-06-04
- Earliest claimed: 2015-01-29
- Assignees: Andreas Stihl AG & Co. KG
- Applicants: Andreas Stihl AG & Co. KG
- Inventors: Patrick Behringer; Sven Keller; Werner Vonderau
- Web page: https://patentgrep.com/patent/US10309362B2

## CPC

- F02N 3/02: having pull-cords
- F02B 63/02: for hand-held tools
- F02B 2075/025: {two}
- F02D 2400/06: Small engines with electronic control, e.g. for hand held tools
- F02N 5/02: of spring type
- F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

A starter device for an internal combustion engine has an entrainer for coupling to the engine. The entrainer and an actuator of the starter device are mounted rotatably about a rotational axis. A damper spring is arranged between and operatively connects the entrainer and the actuator to each other. The starter device has at least one stud, on whose outer periphery the damper spring is mounted. The damper spring is a hinge spring wound from a spring wire. The cross section of the spring wire is rounded on the inner side of the spring wire. At least a portion of the cross section runs linearly on the outer side of the spring wire.

## Claims

### Claim 1

A starter device for an internal combustion engine having a crankshaft and defining a rotational axis, the starter device comprising:
an actuator configured to permit rotation to be imparted thereto to start said engine;
an entrainer having at least one coupling unit for coupling to said crankshaft of said engine;
said entrainer and said actuator being rotatably mounted about said rotational axis;
a damper spring arranged between and operatively connecting said entrainer and said actuator to each other;
at least one stud having an outer periphery;
said damper spring being mounted on said outer periphery of said stud;
said damper spring being a hinge spring wound from spring wire and said spring wire being wound to include a plurality of turns;
said damper spring being tensioned when starting said internal combustion engine whereupon said damper spring becomes tight onto said stud;
said damper spring defining a section plane containing said rotational axis;
said spring wire having a cross section in said section plane;
in said cross section, said spring wire having an axially measured width (e) and a radially measured thickness (d, g, h);
in said cross section, said spring wire further having a radially inner-lying inner side and a radially outer-lying outer side;
in said cross section, said inner side of said spring wire being a rounded inner side with said rounded inner side being in contact engagement with said outer periphery of said stud;
at least a portion of said cross section running linearly at said outer side of said spring wire; and,
said outer side of said spring wire lying exposed over at least half of said turns so as not to be in contact engagement with adjacent components.

### Claim 2 (depends on 1)

The starter device of claim 1, wherein said inner side of said spring wire runs in a through radius (r).

### Claim 3 (depends on 2)

The starter device of claim 2, wherein said radius (r) of said inner side is greater than half of said width (e).

### Claim 4 (depends on 1)

The starter device of claim 1, wherein said at least a portion of said cross section extends over at least 30% of said width (e).

### Claim 5 (depends on 1)

The starter device of claim 1, wherein said spring wire has transverse sides running transversely to said rotational axis and said at least a portion of said cross section runs linearly at said transverse sides.

### Claim 6 (depends on 5)

The starter device of claim 5, wherein said spring wire has respective transitions whereat said outer side runs into corresponding ones of said transverse sides with a radius (s, t).

### Claim 7 (depends on 6)

The starter device of claim 6, wherein said radius (s, t) of said transitions is less than one quarter of said width (e) of said spring wire.

### Claim 8 (depends on 1)

The starter device of claim 1, wherein said thickness (d, g, h) is at least as large as said width (e) of said spring wire.

### Claim 9 (depends on 1)

The starter device of claim 1, wherein said stud is a first stud configured to be part of said actuator; and, said starter device further comprises a second stud configured to be part of said entrainer and said second stud has an outer periphery; and, said actuator and said entrainer are mounted so as to cause the respective outer peripheries thereof to conjointly accommodate said damper spring thereon.

### Claim 10 (depends on 1)

The starter device of claim 1, wherein said damper spring defines an essentially constant turns diameter (f).

### Claim 11 (depends on 1)

The starter device of claim 1, wherein said damper spring has first and second end segments bent over inwardly; and, said damper spring is held on said actuator with said first end segment and held on said entrainer with said second end segment.

### Claim 12 (depends on 1)

The starter device of claim 1, wherein said at least one of said studs has depressions formed in the outer periphery thereof.

### Claim 13 (depends on 1)

The starter device of claim 1, wherein said coupling unit includes at least one pawl pivotally mounted on said entrainer and a cam contour fixedly mounted on said crankshaft so as to rotate therewith; and, said pawl and said cam contour are configured to coact to couple said starter device to said crankshaft.

### Claim 14 (depends on 1)

The starter device of claim 1, wherein said actuator is a rope pulley which is configured so as to permit rotation to be manually imparted thereto with a pull rope.

### Claim 15

A handheld work apparatus comprising:
an internal combustion engine having a crankshaft and defining a rotational axis;
a starter device for said engine;
said starter device including: an actuator configured to permit rotation to be imparted thereto to start said engine; and, an entrainer having at least one coupling unit for coupling to said crankshaft of said engine;
said entrainer and said actuator being rotatably mounted about said rotational axis;
a damper spring arranged between and operatively connecting said entrainer and said actuator to each other;
said starter device further including at least one stud having an outer periphery;
said damper spring being mounted on said outer periphery of said stud;
said damper spring being a hinge spring wound from spring wire;
said damper spring defining a section plane containing said rotational axis;
said spring wire having a cross section in said section plane;
in said cross section, said spring wire having an axially measured width (e) and a radially measured thickness (d, g, h);
in said cross section, said spring wire further having a radially inner-lying inner side and a radially outer-lying outer side;
in said cross section, said inner side of said spring wire being a rounded inner side; and,
at least a portion of said cross section running linearly at said outer side of said spring wire.

### Claim 16

A starter device for an internal combustion engine having a crankshaft and defining a rotational axis, the starter device comprising:
an actuator configured to permit rotation to be imparted thereto to start said engine;
an entrainer having at least one coupling unit for coupling to said crankshaft of said engine;
said entrainer and said actuator being rotatably mounted about said rotational axis;
a damper spring arranged between and operatively connecting said entrainer and said actuator to each other;
at least one stud having an outer periphery;
said damper spring being mounted on said outer periphery of said stud;
said damper spring being a hinge spring wound from spring wire and said spring wire being wound to include a plurality of turns;
said damper spring defining a section plane containing said rotational axis;
said spring wire having a cross section in said section plane;
in said section plane, said spring wire having an axially measured width (e) and a radially measured thickness (d, g, h);
in said cross section, said spring wire further having a radially inner-lying inner side and a radially outer-lying outer side;
said damper spring being mounted between said entrainer and said actuator so as to cause the outer diameter of said damper spring to be reduced when said actuator is actuated by an operator with said outer-lying outer side of said spring wire being exposed over at least half of said turns and lying at a spacing away from adjacent components;
in said cross section, said inner side of said spring wire being a rounded inner side; and,
at least a portion of said cross section running linearly at said outer side of said spring wire.