WO2012140687A1 - Structure d'étrangleur pour outil de travail à main - Google Patents

Structure d'étrangleur pour outil de travail à main Download PDF

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Publication number
WO2012140687A1
WO2012140687A1 PCT/JP2011/002128 JP2011002128W WO2012140687A1 WO 2012140687 A1 WO2012140687 A1 WO 2012140687A1 JP 2011002128 W JP2011002128 W JP 2011002128W WO 2012140687 A1 WO2012140687 A1 WO 2012140687A1
Authority
WO
WIPO (PCT)
Prior art keywords
cleaner
pull knob
choke
carburetor
attached
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2011/002128
Other languages
English (en)
Inventor
Ryou Ono
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Husqvarna AB
Original Assignee
Husqvarna AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Husqvarna AB filed Critical Husqvarna AB
Priority to PCT/JP2011/002128 priority Critical patent/WO2012140687A1/fr
Publication of WO2012140687A1 publication Critical patent/WO2012140687A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/02—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling being chokes for enriching fuel-air mixture
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D11/00—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated
    • F02D11/02—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by hand, foot, or like operator controlled initiation means

Definitions

  • the present invention relates to a choke structure of a handheld work tool that is usable, for instance, in a brushcutter, a chain saw or the like.
  • Patent Literature 1 JP-A-60-56154
  • a pull knob is coupled to a choke valve inside a carburetor via a plurality of linking members or the like, which makes the structure complicated (the arrangement of such a linking portion is similar to that of Patent Literature 1).
  • these linking members also need to be detached. Time-consuming attachment and detachment of the linking members prevents facilitation of the maintenance.
  • An object of the invention is to provide a choke structure of a handheld work tool that is simplified to facilitate maintenance. Further, such a simple structure contributes to reduction in the number of parts, the weight and the cost.
  • a choke structure of a handheld work tool includes: an engine; a carburetor attached to the engine; an air cleaner attached to the carburetor; a choke valve rotatably provided in the carburetor; a rotary piece provided to a rotary shaft of the choke valve; and a pull knob for choke control provided on the air cleaner in such a manner as to be pulled and pushed, in which the rotary piece is provided with a first converter and the pull knob is provided with a second converter, when the pull knob is pushed or pulled, a linear movement of the pull knob is converted into a rotary movement of the choke valve through the first and second converters, and the first and second converters directly contact with each other.
  • the rotary piece of the choke valve and the pull knob are directly coupled to each other via the first and second converters without any linking member or the like therebetween as in a typical arrangement, resulting in a simplified structure.
  • the rotary piece of the choke valve and the pull knob are directly coupled to each other via the first and second converters without any linking member or the like therebetween as in a typical arrangement, resulting in a simplified structure.
  • one of the first and second converters is an engagement pin provided to one of the rotary piece and the pull knob
  • the other of the first and second converters is an engagement portion provided to the other of the rotary piece and the pull knob and engaged with the engagement pin.
  • the first and second converters are provided by simple components, i.e., the engagement pin and the engagement portion, which only need to be engaged with each other to allow choke control.
  • the arrangement does not require a high accuracy in dimensions such as the projecting length of the engagement pin and the dimension of the engagement portion, so that production and assembly can be facilitated.
  • an engagement/disengagement direction of the engagement pin and the engagement portion coincides with an attachment/detachment direction of the air cleaner relative to the carburetor.
  • the engagement pin and the engagement portion can be engaged or disengaged at the same time as the air cleaner is attached or detached relative to the carburetor, so that assembly and disassembly can be further facilitated.
  • the air cleaner includes: a cleaner case attached to the carburetor to accommodate an element; and a cleaner cover removably attached to the cleaner case to cover the cleaner case, and the pull knob is attached to the cleaner case.
  • the pull knob is attached to the cleaner case, which is the closest to the carburetor in the air cleaner.
  • the pull knob includes an operating portion, and when the pull knob is pushed in, the operating portion is fitted in a cutout provided to the cleaner cover such that a surface of the operating portion and a surface of the cleaner cover are flushed to be continuous as a whole.
  • the surface of the cleaner cover and the surface of the operating portion of the pull knob are flushed to be continuous.
  • the cleaner cover is attached to the cleaner case with a screw, and one of the cleaner case and the cleaner cover is provided with a projection that projects toward the other of the cleaner case and the cleaner cover, and the other of the cleaner case and the cleaner cover is provided with an insertion hole in which the projection is inserted.
  • the position of the cleaner cover is deviated in a rotation direction of the screw due to friction between the screw head and the cleaner cover.
  • the through hole and the projection are engaged with each other to prevent a deviation in the relative positions of the cleaner case and the cleaner cover in the rotation direction.
  • a clearance between the cleaner cover and the operating portion is kept enough for the cleaner cover not to contact and interfere with the operating portion of the pull knob fitted in the cutout of the cleaner cover.
  • the operating portion can be reliably operated to push and pull the pull knob.
  • the pull knob includes a slidable portion configured to be attachable or detachable relative to an inside of an accommodating portion provided in the cleaner case, the slidable portion accommodated inside the accommodating portion in a slidable manner along a direction of the linear movement, and the slidable portion includes a contact piece elastically deformed in attachment or detachment relative to the accommodating portion, the contact piece coming into contact with a predetermined position in the accommodating portion to define a sliding amount of the slidable portion.
  • the elastic deformation of the contact piece of the pull knob allows the attachment or detachment of the slidable portion of the pull knob relative to the accommodating portion of the cleaner case. Further, the contact piece comes into contact with the predetermined position in the accommodating portion, thereby preventing the pull knob from accidentally coming out of the accommodating portion as well as defining the sliding amount of the slidable portion.
  • Fig. 1 is an exploded perspective view showing a main body of a brushcutter according to an exemplary embodiment of the invention.
  • Fig. 2 is an exploded perspective view showing a primary part of the exemplary embodiment.
  • Fig. 3 is a perspective view showing a primary part of a cleaner case according to the exemplary embodiment.
  • Fig. 4 is a perspective view showing a state where a pull knob is pushed in according to the exemplary embodiment.
  • Fig. 5 is a perspective view showing a state where the pull knob is pulled out according to the exemplary embodiment.
  • a brushcutter 1 (handheld work tool) includes a main body 2 that includes a single-cylinder two-stroke engine 4 as a primary element, an operating rod 3 that is coupled to the main body 2 at a base end thereof, an attachment such as a tip saw or a nylon cutter that is attached to a distal end of the operating rod 3, and a handle that is attached in the middle of the operating rod 3.
  • the engine 4 may be provided by a four-stroke engine.
  • a carburetor 5 is attached to the engine 4 via an insulator 5A made of synthetic resin, and an air cleaner 6 is attached to the carburetor 5.
  • An exhaust muffler 7 is attached to the engine 4 on the side opposite to the carburetor 5.
  • a fuel tank 8 is attached to the lower side of the engine 4. A fuel in the fuel tank 8 is sucked up into the carburetor 5.
  • a recoil starter 9 having an operating knob 91 with a pull string.
  • a cooling fan 10 having a plurality of vanes 11 and a clutch-shoe assembly of a centrifugal clutch 20.
  • the centrifugal clutch 20 is attached to the outer side of the cooling fan 10.
  • the centrifugal clutch 20 includes, in addition to the clutch-shoe assembly including a clutch shoe, a clutch drum 21 that is frictionally engaged with the clutch shoe centrifugally rotated outward in a radial direction.
  • a coupling shaft 22 is attached to the clutch drum 21.
  • a drive shaft 31 rotatably housed in the operating rod 3 is splined to the coupling shaft 22.
  • a clutch housing 23 made of synthetic resin covers the cooling fan 10 and the centrifugal clutch 20.
  • the clutch housing 23 is screwed onto a fan housing 41 integrally formed with a crankcase of the engine 4.
  • the clutch housing 23 is shaped as a trumpet opened wider at a position closer to the main body 2.
  • a driving force of the engine 4 is transferred from the crankshaft to the drive shaft 31 via the centrifugal clutch 20, and is transferred to the attachment from the drive shaft 31 via an appropriate gear provided to a distal end of the drive shaft 31.
  • a cooling air is sucked through an opening 43, which is provided to an opposed surface 42 of the fan housing 41, with the assistance of the cooling fan 10 rotated along with the crankshaft. The sucked air is then directed toward a cylinder 4A of the engine 4 (see arrow A1).
  • the insulator 5A is attached with three screws 5B.
  • the insulator 5A corresponds to an intake port provided to the cylinder 4A of the engine 4.
  • the carburetor 5 is attached to the insulator 5A via a gasket 5C with a pair of screws 5D.
  • the screws 5D are also used to attach the air cleaner 6 to the carburetor 5.
  • the air cleaner 6 includes a cleaner case 61 that is screwed onto the carburetor 5 with the screws 5D, a sponge element 62 that is housed in the cleaner case 61, and a cleaner cover 64 that is attached to the cleaner case 61 with an operating screw 63.
  • a gasket (not shown) is also interposed between the cleaner case 61 and the carburetor 5.
  • the carburetor 5 includes a bore 51 through which intake air passes, a choke valve 52 rotatably housed in the bore 51 at an upstream position, and a throttle valve (not shown) housed in the bore 51 at a downstream side.
  • a butterfly valve is employed as each of the choke valve 52 and the throttle valve, but, instead of that, a rotary valve or the like may alternatively be employed.
  • the rotary shaft of the choke valve 52 and the rotary shaft of the throttle valve extend from the external surface of the carburetor 5.
  • Rotary pieces 53 and 54 are attached to these rotary shafts in an externally-operable manner, respectively.
  • the respective positions of the choke valve 52 and the rotary piece 53 shown in Fig. 2 are related to a state where the engine is in a normal-drive mode and choke is not applied. In this state, while the rotary piece 53 and the rotary piece 54 are not in contact with each other, the rotary piece 54 and the throttle valve are biased to an idling position.
  • a biasing unit for the rotary piece 54 or the like (not shown in Fig. 2) is attached to the rotary shaft of the throttle valve at the end opposite to the rotary piece 54.
  • Such a rotary operation of the choke valve 52 is effected by an engagement pin 55 that projects from the rotary piece 53 and an engagement portion of a pull knob 80 for choke control that is engaged with the engagement pin 55.
  • the pull knob 80 includes an operating portion 82 having a recess 81 in which a finger of a user or the like can be inserted, and a slidable portion 83 with a predetermined length that is integrally formed with the operating portion 82.
  • a choke mark 84 is provided on a surface of the operating portion 82.
  • An engagement portion 85 that is shaped as a cutout and is opened toward the engagement portion 55 is formed in a lengthwise middle of the slidable portion 83.
  • a contact piece 86 laterally projects from the slidable portion 83 on a base-end side relative to the engagement portion 85.
  • the slidable portion 83 of the pull knob 80 is housed in an accommodating portion 65 with a predetermined length provided to one side (right side in Fig. 2, in this exemplary embodiment) of the cleaner case 61.
  • the accommodating portion 65 is formed as a groove having a U-shaped cross section that is opened at a lengthwise end and at a side near the engagement pin 55.
  • the accommodating portion 65 includes an opposed wall 66 opposed to the engagement portion 55, and lateral walls 67 and 68 provided on both sides of the opposed wall 66.
  • the lateral wall 67 on the inner side has a cut portion 67A formed by cutting the lateral wall 67 in the lengthwise direction over a predetermined length.
  • the cut portion 67A is continuous with a groove-like portion 69 provided to the inner portion of the cleaner case 61.
  • the lateral wall 68 on the outer side has an opening 68A opened along the lengthwise direction over a predetermined length.
  • the contact piece 86 of the slidable portion 83 is set in the opening 68A.
  • the length of the opening 68A is larger than the length of the contact piece 86 by a dimension S.
  • the dimension S corresponds to a stroke amount of the pull knob 80.
  • the lower side of the contact piece 86 is in contact with a bottom 68B of the opening 68A.
  • the pull knob 80 is upwardly pulled out, the upper side of the contact piece 86 is slid by the dimension S to come into contact with a top 68C of the opening 68A.
  • the pull knob 80 is slidable in the lengthwise direction of the slidable portion 83 by a stroke corresponding to the dimension S.
  • the contact piece 86 and the opening 68A define the stroke amount and the contact piece 86 is retained within the stroke.
  • Such a linear movement of the pull knob 80 is converted into a rotary movement via the engagement portion 85 and the engagement pin 55, and the choke valve 52 is rotated by a resulting rotary amount, so that the choke valve 52 is opened or closed.
  • the engagement pin 55 and the engagement portion 85 serve as first and second converters according to the invention.
  • Fig. 3 shows a state where the pull knob 80 is pushed in.
  • the contact piece 86 is in contact with the bottom 68B and the choke valve 52 is opened, so that choke is not applied.
  • the choke valve is closed and, thus, choke is applied.
  • the contact piece 86 of the slidable portion 83 is formed as a cantilever with elasticity. Since the contact piece 86 is in an elastically deformable manner, it is possible to attach the slidable portion 83 to the accommodating portion 65 or detach from it by pushing the contact piece 86 for condensing the projecting amount when maintenances are required. When being housed in the opening 68A, the contact piece 86 is elastically recovered to contact the bottom 68B or the top 68C of the opening 68A.
  • the distal end of the slidable portion 83 is shaped like a wedge, so that the slidable portion 83 can be smoothly inserted into the accommodating portion 65.
  • the rotary piece 53 of the carburetor 5 can be rotated by linearly pushing and pulling the pull knob 80 engaged with the engagement pin 55.
  • the engagement portion 85 of the pull knob 80 is opened toward the engagement pin 55, and an attachment/detachment direction of the cleaner case 61 coincides with an engagement/disengagement direction of the engagement portion 85 and the engagement pin 55.
  • a cutout 64A is formed in the cleaner cover 64.
  • the cutout 64A corresponds to the operating portion 82 of the pull knob 80 attached to the cleaner case 61.
  • the operating portion 82 is fitted in the cutout 64.
  • Insertion holes 61B penetrating in the attachment/detachment direction are provided to the outer edges of the cleaner case 61 opposed to each other at a distance. In attachment of the cleaner cover 64 to the cleaner case 61, projections 64B projecting from the cleaner cover 64 are inserted in the insertion holes 61B.
  • Fig. 4 shows that the cleaner cover 64 is attached to the cleaner case 61, and the pull knob 80 is pushed in to set the normal-drive mode where choke is not applied. In this state, the surface of the operating portion 82 and the surface of the cleaner cover 64 are flushed to be continuous as a whole. In contrast, when choke is applied, the pull knob 80 is upwardly pulled out as shown in Fig. 5, so that a large step is defined between the surface of the operating portion 82 and the surface of the cleaner cover 64.
  • the scope of the invention is not limited to the above-described embodiment but includes the following modifications.
  • the rotary piece 53 of the choke valve 52 is provided with the engagement pin 55
  • the pull knob 80 is provided with the engagement portion 85 shaped as a cutout that is engaged with the engagement pin 55.
  • the choke valve 52 may alternatively be provided with a pinion gear and the pull knob 80 may alternatively be provided with a rack gear engageable with the pinion gear.
  • the accommodating portion 65 is provided on the right side of the cleaner case 61 in the above exemplary embodiment, the accommodating portion 65 may be provided on the left side, the upper side or the lower side. In other words, where the accommodating portion 62 should be provided may be determined in consideration of a direction of attaching the engagement pin 55 to the carburetor 5 or the like.
  • the accommodating portion 65 is provided to the cleaner case 61 in the above exemplary embodiment. Alternatively, such an accommodating portion 65 may be provided to the cleaner cover 64, which also falls within the scope of the invention.
  • the rotary piece 53 is provided with the engagement pin 55 and the pull knob 80 is provided with the engagement portion 85 in the above exemplary embodiment, the rotary piece 53 may be provided with an engagement portion and the pull knob 80 may be provided with an engagement pin.
  • the cleaner case 61 is provided with the insertion holes 61B and the cleaner cover 64 is provided with the projections 64B, the cleaner case 61 may be provided with a projection(s) and the cleaner cover 64 may be provided with an insertion hole(s).
  • the invention is usable not only in a brushcutter but also in an engine-driven handheld work tool such as a chain saw or an engine blower.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Means For Warming Up And Starting Carburetors (AREA)

Abstract

L'invention concerne une structure d'étrangleur d'un outil de travail à main, comprenant : un moteur ; un carburateur (5) attaché au moteur ; un filtre à air (6) attaché au carburateur (5) ; un étrangleur (52) mis en œuvre de manière rotative dans le carburateur (5) ; une pièce rotative (53) mise en œuvre sur un arbre rotatif de l'étrangleur (52) ; et une tirette (80) pour commande d'étrangleur mise en œuvre sur le filtre à air (6) de manière à être tirée et poussée, la pièce rotative (53) comportant un premier convertisseur (55) et la tirette (80) comportant un second convertisseur (85), quand la tirette (80) est poussée ou tirée, un mouvement linéaire de la tirette (80) étant converti en un mouvement de rotation de l'étrangleur (52) par le biais du premier et du second convertisseur (55, 85), et le premier et le second convertisseur (55, 85) étant directement en contact l'un par rapport à l'autre.
PCT/JP2011/002128 2011-04-11 2011-04-11 Structure d'étrangleur pour outil de travail à main Ceased WO2012140687A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2011/002128 WO2012140687A1 (fr) 2011-04-11 2011-04-11 Structure d'étrangleur pour outil de travail à main

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2011/002128 WO2012140687A1 (fr) 2011-04-11 2011-04-11 Structure d'étrangleur pour outil de travail à main

Publications (1)

Publication Number Publication Date
WO2012140687A1 true WO2012140687A1 (fr) 2012-10-18

Family

ID=44120700

Family Applications (1)

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PCT/JP2011/002128 Ceased WO2012140687A1 (fr) 2011-04-11 2011-04-11 Structure d'étrangleur pour outil de travail à main

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Country Link
WO (1) WO2012140687A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6056154A (ja) 1983-09-06 1985-04-01 Kawasaki Heavy Ind Ltd 汎用エンジンのスロツトルコントロ−ル装置
US5485814A (en) * 1995-03-01 1996-01-23 Wci Outdoor Products, Inc. Resetting ignition switch for a gasoline powered chain saw
EP1389678A1 (fr) * 2002-08-12 2004-02-18 Tecumseh Products Company Système de règlage pour machines à combustion interne
FR2880072A1 (fr) * 2004-12-29 2006-06-30 Stihl Ag & Co Kg Andreas Systeme de carburateur
EP1806212A1 (fr) * 2004-04-08 2007-07-11 Husqvarna Outdoor Products, Inc. Système d'allumage pour outils portatifs à moteur

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6056154A (ja) 1983-09-06 1985-04-01 Kawasaki Heavy Ind Ltd 汎用エンジンのスロツトルコントロ−ル装置
US4631153A (en) * 1983-09-06 1986-12-23 Kawasaki Jukogyo Kabushiki Kaisha Throttle control device for general purpose engine
US5485814A (en) * 1995-03-01 1996-01-23 Wci Outdoor Products, Inc. Resetting ignition switch for a gasoline powered chain saw
EP1389678A1 (fr) * 2002-08-12 2004-02-18 Tecumseh Products Company Système de règlage pour machines à combustion interne
EP1806212A1 (fr) * 2004-04-08 2007-07-11 Husqvarna Outdoor Products, Inc. Système d'allumage pour outils portatifs à moteur
FR2880072A1 (fr) * 2004-12-29 2006-06-30 Stihl Ag & Co Kg Andreas Systeme de carburateur

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