MANUALLY GUIDED IMPLEMENT

• US 20080006240A1
• Filed: 07/09/2007
• Published: 01/10/2008
• Est. Priority Date: 07/08/2006
• Status: Active Grant

• Current Assignee: Andreas STIHL AG & Company KG (Stihl Holding AG & Company KG)
• Original Assignee: Andreas STIHL AG & Company KG (Stihl Holding AG & Company KG)
• Inventors: Bergmann, Lars, Anspann, Stefan, Uhl, Klaus-Martin, Geyer, Klaus
• Granted Patent: US 7,373,921 B2
• Time in Patent Office: Days
• US Class Current: 123/319
• CPC Class Codes: F02B 63/02 for hand-held tools
• CPC Class Codes: F02D 11/02 characterised by hand, foot, or like operator controlled initiation means
• CPC Class Codes: F02D 11/04 characterised by mechanical control linkages F02D11/06 takes precedence

Abstract

A manually guided implement having a motor unit and a tool unit driven by the motor unit. The motor unit includes an internal combustion engine having a carburetor, and a butterfly valve. A throttle acts upon the butterfly valve via a transfer mechanism. A speed regulator is provided for the internal combustion engine. The transfer mechanism is divided into two transfer portions. The speed regulator is a mechanical speed regulator and is disposed between two transfer portions such that the throttle, via the first transfer portion associated therewith, as well as the speed regulator together act upon the second transfer portion, which is associated with the butterfly valve, whereby as its speed increases, the speed regulator effects a closing of the butterfly valve.

Claims

1. A manually guided implement having a motor unit (1) that includes an internal combustion engine having a carburetor (3), wherein a butterfly valve (4) is disposed in said carburetor for controlling the power of the internal combustion engine, comprising:

a tool unit that is adapted to be driven by said motor unit (1);

a transfer mechanism (5) divided into a first transfer to portion (8) and a second transfer portion (9) wherein said second transfer portion is associated with said butterfly valve (4);

a throttle (6) that is associated with said first transfer portion (8) and is adapted to act upon said butterfly valve (4) via said transfer mechanism (5); and

a mechanical speed regulator (7) for the internal combustion engine, wherein said speed regulator (7) is disposed between said first transfer portion (8) and said second transfer portion (9) such that said throttle (6), via said first transfer portion (8) as well as said speed regulator (7) together act upon said second transfer portion (9), and wherein said speed regulator (7), as its speed increases, is adapted to effect a closing of said butterfly valve (4).

2. An implement according to claim 1, wherein said speed regulator (7) is a speed limiter that above a prescribed threshold speed is adapted to effect a closing of said butterfly valve (4).

3. An implement according to claim 1 wherein said speed regulator (7), at least relative to a closing direction (10) of said butterfly valve (4), is connected essentially rigidly with said butterfly valve (4) via said second transfer portion (9), wherein an in particular biased elastic spring device (12) is provided, and wherein said throttle (6), together with said associated first transfer portion (8), are coupled to said to second transfer portion (9) via said spring device (12).

4. An implement according to claim 3, wherein said second transfer portion (9) engages a pivotable coupling shaft (14) on which said speed regulator (7) engages, wherein said first transfer portion (8) includes a coupling lever (15) that is pivotably mounted on said coupling shaft (14), and wherein said coupling shaft (14) and said coupling lever (15) are connected to one another in a pivot direction by means of said spring device (12), which is in particular embodied as a torsion spring.

5. An implement according to claim 3, wherein said throttle (6) is provided with a return spring (42), and wherein said return spring is stiffer than is said spring device (12).

6. An implement according to claim 1, wherein said spring regulator (7) includes a regulating shaft (16) that is driven by said internal combustion engine, wherein said regulating shaft (16) is provided with at least one, and in particular two, oppositely disposed centrifugal weights (17), wherein means are provided for producing an axial regulation movement, and wherein said at least one centrifugal weight (17) is mounted so as to be pivotable in a radial direction and to act upon said means for producing an axial regulation movement.

7. An implement according to claim 6, wherein said at least to one centrifugal weight (17) is mounted so as to be pivotable about a pivot axis (49) disposed in particular tangential relative to an axis of rotation (21) of said regulating shaft (16), and wherein said centrifugal weight (17) has a mass center (54) that is disposed within a regulation range radially inwardly of said pivot axis.

8. An implement according to claim 6, wherein said means for producing an axial regulation movement is formed by an axially displaceable regulating sleeve (18) that is disposed on said regulating shaft (16).

9. An implement according to claim 6, wherein a pivot lever (19) is provided, wherein said means for producing an axial regulation movement acts upon said pivot lever (19), and wherein a pivot axis (20) of said pivot lever (19) is disposed essentially perpendicular to an axis of rotation (21) of said regulating shaft (16).

10. An implement according to claim 9, wherein said arrangement comprised of said at least one centrifugal weight (17) and said means for producing an axial regulation movement is disposed in an enclosed regulation chamber (22) that is in particular provided with a lubricant, and wherein said pivot lever (19) is guided out of said regulation chamber (22) in the vicinity of said pivot axis (20) of said pivot lever (19) and on the outside acts upon second transfer portion to (9).

11. An implement according to claim 1, wherein said speed regulator (7) is disposed in said tool unit (2).

12. An implement according to claim 11, wherein a point of connection is provided in said tool unit (2) between said first and second transfer portions (8,9).

13. An implement according to claim 11, wherein at least one of said motor unit (1) and said tool unit (2) is provided for a modular exchange.

14. An implement according to claim 11, wherein said tool unit (2) is provided with a tool gear mechanism (26), and wherein said speed regulator (7) is disposed in said tool gear mechanism (26).

15. An implement according to claim 11, wherein said tool unit (2) is provided with a supporting housing (25) and a tool gear mechanism (26), wherein a guide tube (23) having a transfer shaft (24) extending therein is disposed between said motor unit (1) and said tool unit (2), wherein said transfer shaft (24) is guided through said supporting housing (25) of said tool unit (2) to said tool gear mechanism (26), and wherein said speed regulator (7) is driven by said transfer shaft (24) and is disposed in said supporting housing (25) of said tool unit (2).

16. An implement according to claim 1, wherein said speed regulator (7) is disposed within a crankcase (27) on a crankshaft (28) of said internal combustion engine, which is embodied in particular as a loss-lubricated and preferably two-cycle engine.

17. An implement according to claim 16, wherein said speed regulator (7), in an axial direction of said crankshaft (28), is disposed between a crank web (29), in particular between a crankshaft bearing (30) disposed beyond said crank web (29), and a centrifugal clutch that is adapted to be disposed on said crankshaft (28).

18. An implement according to claim 16, wherein said speed regulator (7) is adapted to be lubricated by a fuel/air mixture disposed in said crankcase (27), in particular through a crankshaft bearing (30).

19. An implement according to claim 16, wherein a pivot lever (19) is provided having a lever arm (31) disposed outwardly of said crankcase (27), and wherein said lever arm (31) is guided essentially parallel to said crankshaft (28) and inwardly in a direction toward a center of said crankshaft (28) and below said carburetor (3).

20. An implement according to claim 19, wherein said pivot lever (19) is connected with an actuating lever (13) of a coupling shaft (14) via a connecting rod (33), and wherein said pivot lever (19) is suspended in a slot (34) of said actuating lever (13).

21. An implement according to claim 20, wherein said coupling shaft (14) is formed by a shaft (40) that supports said butterfly valve (4).

22. An implement according to claim 21, wherein said first transfer portion (8) includes a coupling shaft (15), and wherein said coupling shaft (15), for engagement of said first transfer portion (8), and said actuating lever (13), for engagement of said speed regulator (7), are disposed on opposite sides of said carburetor (3) relative to an axial direction of said shaft (40) of said butterfly valve (4).