WIRE THROTTLE ADJUSTMENT DEVICE

Abstract

The need for maintenance regarding wire stretching and position displacement between a throttle valve and an operation member is eliminated. A wire throttle adjustment device 1 is for performing open-close adjustment of a throttle valve by pull operation of a wire 2. The wire throttle adjustment device 1 includes an operation member 10 connected to an end part 2A of the wire 2 and configured to perform the pull operation of the wire 2. The operation member 10 includes an action part 11 that is elastically deformable by the pull operation of the wire 2 in a fully-opened state of the throttle valve. The action part 11 includes an elastically-deformable elastic arm part 12 configured to swing together with the operation part 15 and extending from the pivotally-supported part 14, and the end part of the wire 14 is connected to a tip part of the elastic arm part 12.

Claims

1. A wire throttle adjustment device for performing open-close adjustment of a throttle valve by pull operation of a wire, comprising: an operation member connected to an end part of the wire and configured to perform the pull operation of the wire, wherein the operation member includes an action part that is elastically deformable by the pull operation of the wire in a fully-opened state of the throttle valve.

2. The wire throttle adjustment device according to claim 1, wherein the operation member includes a pivotally-supported part pivotally supported on a handle frame, and an operation part swingably operable about a shaft supporting the pivotally-supported part, the action part includes an elastically-deformable elastic arm part configured to swing together with the operation part and extending from the pivotally-supported part, and the end part of the wire is connected to a tip part of the elastic arm part.

3. The wire throttle adjustment device according to claim 2, wherein at the tip part of the elastic arm part, a wire guide configured to guide the end part of the wire to the tip part of the elastic arm part is provided so as to extend around the pivotally-supported part.

4. The wire throttle adjustment device according to claim 2, wherein the operation member is configured such that the action part, the pivotally-supported part, and the operation part are integrally molded.

5. An engine-driven handheld or backpack machine comprising: the wire throttle adjustment device according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 is a view for describing an entire configuration of a wire throttle adjustment device of an embodiment of the present invention.

[0014] FIG. 2 is a view for describing an adjustment member of the wire throttle adjustment device of the embodiment of the present invention.

[0015] FIG. 3 is a view for describing an example (a chain saw) of an engine-driven handheld machine including the wire throttle adjustment device of the embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

[0016] An embodiment of the present invention will be described below with reference to drawings. FIG. 1 illustrates an entire configuration of a wire throttle adjustment device of an embodiment of the present invention. A wire throttle adjustment device 1 is configured to perform open-close adjustment of a throttle valve (not shown) of a carburetor 3 by pull operation of a wire 2. Wire throttle adjustment device 1 includes wire 2 and an operation member (a throttle lever) 10. In a basic configuration of wire throttle adjustment device 1, the throttle valve is biased in a closing direction by a not-shown spring, and is operated to open by pulling of wire 2 against elastic force of the spring.

[0017] Operation member 10 includes a pivotally-supported part 14 pivotally supported on a frame (a handle frame) 20 forming a handle of, e.g., an engine-driven handheld or backpack machine equipped with wire throttle adjustment device 1. As indicated by an arrow in the figure, operation member 10 is swingably supported about a shaft 14A supporting pivotally-supported part 14. Operation member 10 includes an operation part 15. Fingers holding the handle operate operation part 15 to swingably operate the entirety of operation member 10 about shaft 14A supporting pivotally-supported part 14.

[0018] Moreover, operation member 10 includes a locking part 16. In the state in which locking part 16 is locked by a lock lever 21 provided at handle frame 20, the swing of operation member 10 is locked. The locked lock lever 21 is released by grasping of the handle by an operator, and then, is disengaged from locking part 16. In the state in which the operator does not grasp the handle, the throttle valve cannot be operated to open by operation of operation member 10.

[0019] Such an operation member 10 includes an action part 11, and an end part 2A of wire 2 is connected to action part 11. Wire 2 is disposed through a wire cover 2B, and extends from an arrangement position of carburetor 3 to a handle position. End part 2A of wire 2 is connected to a tip part 11A of action part 11.

[0020] Action part 11 includes an elastically-deformable elastic arm part 12 configured to swing together with operation part 15 and extending from pivotally-supported part 14. End part 2A of wire 2 is connected to a tip part of elastic arm part 12. Moreover, at the tip part of elastic arm part 12, a wire guide 13 configured to guide end part 2A of wire 2 to the tip part of elastic arm part 12 is provided so as to extend around pivotally-supported part 14.

[0021] The functions of operation member 10 will be described in more detail with reference to FIG. 2. When the fingers operate, in a direction indicated by an arrow a, operation member 10 pivotally supported by shaft 14A, the entirety of operation member 10 including operation part 15 and action part 11 is swingably operated about shaft 14A. In such a state, action part 11 swings together with operation part 15 to pull wire 2, and brings the throttle valve to a fully-opened state. When operation member 10 is further swingably operated in the fully-opened state of the throttle valve, tension of wire 2 elastically deforms action part 11 (elastic arm part 12) in a direction indicated by an arrow b.

[0022] With the above-described operation member 10, action part 11 (elastic arm part 12) elastically deforms to relieve the tension of wire 2 before excessive tension is applied to wire 2. Thus, wire 2 can be pulled with constant force regardless of the magnitude of force for operating operation part 15 with the fingers, and therefore, application of the excessive tension to wire 2 can be reduced. Moreover, when engine vibration is transmitted to wire 2 via the throttle valve, such vibration is absorbed by elastic deformation of action part 11 (elastic arm part 12). Thus, action part 11 functions as a damper, and transmission of the engine vibration to the fingers operating operation member 10 can be reduced.

[0023] With wire throttle adjustment device 1 including the above-described operation member 10, even when, e.g., stretching of wire 2 or position displacement between the throttle valve and operation member 10 is caused due to repeated use, stretching of wire 2, etc. can be absorbed by elastic deformation of action part 11 (elastic arm part 12) within a range of elastic deformation of action part 11 (elastic arm part 12). Thus, an operation state in which the throttle valve is fully opened can be constantly brought without maintenance such as adjustment of a connection position of the end part of wire 2 and adjustment of the length of wire 2. Note that in this case, an initial operation state needs to be set such that the fully-opened state of the throttle valve is brought before an operation limit of operation member 10. With this configuration, when stretching of wire 2 is caused, the fully-opened state is brought in such a manner that operation member 10 is further operated deeper to the vicinity of the operation limit with respect to an operation position at which an original fully-opened state is brought.

[0024] Elastic deformation of operation member 10 effectively functions not only for temporal stretching of wire 2 but also for an individual difference in wire 2 in assembly. That is, even with a certain degree of individual difference in the length of wire 2 in assembly, such an individual difference can be absorbed by elastic deformation of action part 11 (elastic arm part 12). Thus, elaborate initial adjustment for bringing the fully-opened state in an appropriate operation state can be omitted. This allows shortening of an assembly time, and productivity of a machine with which the wire throttle adjustment device 1 is to be assembled can be enhanced.

[0025] Wire guide 13 extending from the tip part of elastic arm part 12 is formed such that a groove part configured to guide wire 2 is curved around pivotally-supported part 14. With this configuration, when operation member 10 is swingably operated about shaft 14A, a point at which wire 2 is separated from wire guide 13 is substantially maintained constant. Since such a wire guide 13 extends from the tip part of elastic arm part 12, tension can constantly act on wire 2 in a stable state even when elastic deformation of action part 11 (elastic arm part 12) is caused.

[0026] Operation member 10 can be formed of an integrally-molded resin member including action part 11, pivotally-supported part 14, operation part 15, and locking part 16. In this case, the degree of elastic deformation of action part 11 can be optionally set by, e.g., a resin material or shape.

[0027] FIG. 3 illustrates a chain saw as an example of the engine-driven handheld machine including the wire throttle adjustment device 1. A chain saw 30 includes a handle 31, and operation member (throttle lever) 10 and lock lever 21 of wire throttle adjustment device 1 as described above are attached to a handle frame of handle 31. The illustrated chain saw 30 includes, for example, a main body 32 having an engine (a carburetor), a front bar 33, a brake lever 34, a guide bar 35, and a saw chain 36. Wire throttle adjustment device 1 of the embodiment of the present invention can be employed not only for the illustrated chain saw 30 but also for various engine-driven handheld or backpack machines such as a hedge trimmer, a brush cutter, a blower/vacuum blower, and a sprayer/duster, and can provide the above-described functions.

REFERENCE SIGNS LIST

[0028] 1 Wire throttle adjustment device [0029] 2 Wire [0030] 2A End part [0031] 2B Wire cover [0032] 3 Carburetor [0033] 10 Operation member (throttle lever) [0034] 11 Action part [0035] 11A Tip part [0036] 12 Elastic arm part [0037] 13 Wire guide [0038] 14 Pivotally-supported part [0039] 14A Shaft [0040] 15 Operation part [0041] 16 Locking part [0042] 20 Handle frame [0043] 21 Lock lever [0044] 30 Chain saw (handheld machine) [0045] 31 Handle [0046] 32 Main body [0047] 33 Front bar [0048] 34 Brake lever [0049] 35 Guide bar [0050] 36 Saw chain