JP2013119778A - Engine working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the workability of fuel recovery work from a fuel tank of an engine working machine.SOLUTION: A fuel tank 24 for storing fuel supplied to an engine is provided in a working machine body 12 of an engine working machine such as an engine cutter. The working machine body 12 is provided with: a carburetor 25 that evaporates fuel in the fuel tank 24 supplied from a fuel supply tube 31; and a fuel recovery pump 33 that is provided between a discharging tube 36 for discharging fuel from the carburetor 25 and a recovery tube 42 in order to discharge fuel in the fuel tank 24 from the recovery tube 42 to the outside.

Description

  The present invention relates to an engine work machine configured to drive a work tool such as a rotary tool using an engine as a drive source.

  As a working machine using an engine as a driving source, there are a cutter, a brush cutter, a chain saw, a trimming machine, a blower, and the like. The cutter is an engine working machine for cutting stones and concrete with a disk-shaped rotary tool, and the brush cutter is an engine working machine used to cut grass and small diameter trees using a cutting blade as a work tool. There is also a mower. A chain saw is an engine working machine used to cut wood or the like using a saw chain, that is, a chain saw. A trimming machine is an engine working machine used for planting and pruning trees such as hedges using a pair of blades that reciprocate linearly as a work tool, and is also called a hedge trimmer. Further, as an engine working machine, there is a blower or the like that discharges air by rotationally driving a blower as a working tool.

  The engine working machine is provided with a carburetor, that is, a carburetor, in order to generate an air-fuel mixture supplied to the combustion chamber of the engine. The carburetor has an intake passage through which air purified by an air filter flows. The fuel supplied from the fuel tank is discharged into the intake passage, and the fuel vaporized in the intake passage enters the engine. Supplied. Patent Document 1 describes an engine cutter in which a rotary tool as a work tool is driven by an engine, and the engine and the carburetor are incorporated in the housing.

JP 2010-285974 A

  The carburetor is supplied with fuel stored in a fuel tank disposed on the lower side of the engine, and the carburetor includes a fuel supply tube for supplying the fuel in the fuel tank to the carburetor. An overflow tube for returning surplus fuel in the carburetor to the fuel tank is connected. A priming pump is connected to the other end of the overflow tube. When the priming pump is operated, the fuel in the fuel tank is sucked into the carburetor through the fuel supply tube. The surplus fuel in the carburetor is returned to the fuel tank by a return pipe connected to the priming pump.

  When the engine work machine is not used for a long period of time, the fuel in the fuel tank is prevented from deteriorating and the fuel tank is returned to the fuel recovery container in order to prevent fuel clogging from occurring in the carburetor. It is preferable to make it empty. However, the fuel filler port for supplying the fuel into the fuel tank is arranged on the side surface or the upper surface of the engine working machine. When recovering fuel from the fuel tank, the engine working machine is lifted to It is necessary to incline the fuel to discharge the fuel from the fuel filler port and transfer it to the fuel recovery container.

  For this reason, especially in a large engine working machine such as an engine cutter, the heavy engine working machine must be lifted or tilted. Therefore, it is ensured that the fuel is not leaked from the fuel collecting container during fuel recovery. It is necessary to collect the fuel, and there is a problem that a heavy burden is imposed on the worker when collecting the fuel.

  An object of the present invention is to improve workability of a fuel recovery work from a fuel tank of an engine working machine.

  An engine work machine according to the present invention is an engine work machine that drives a work tool using an engine as a drive source, the work machine main body provided with the engine and a fuel tank that stores fuel supplied to the engine, And a fuel recovery pump for discharging the fuel in the fuel tank to the outside. The engine working machine of the present invention is provided with a carburetor for vaporizing fuel in the fuel tank supplied by a fuel supply tube in the working machine main body, an exhaust tube for discharging fuel from the carburetor, and an external to the working machine main body. The fuel recovery pump is provided between a recovery tube and a recovery tube, and the fuel in the fuel tank is discharged from the recovery tube to the outside through the vaporizer.

  In the engine working machine of the present invention, the fuel recovery pump includes an elastically deformable pump member having an inflatable / shrinkable pump chamber communicating with the discharge tube and the flow path of the recovery tube, and the elastic deformation of the pump member. The discharge tube has a return valve for discharging the fuel flowing out from the vaporizer to the recovery tube. The engine working machine according to the present invention has an inflow flow path switching that switches between a state in which the flow path of the discharge tube communicates with the pump chamber and a state in which the flow path of the discharge tube communicates with the recovery tube via a bypass flow path. It has a valve, The fuel filled in the said discharge tube and the said collection tube is discharged outside from the said collection tube via the said bypass flow path with dead weight.

  The engine working machine according to the present invention includes a return tube that returns the fuel discharged from the pump chamber to the fuel tank, a state in which the pump chamber communicates with a flow path in the return tube, and the pump chamber that is connected to the recovery tube. It has a recovery flow path switching valve that switches to a state of communicating with the flow path, and the fuel recovery pump is also used as a priming pump that supplies fuel to the carburetor when the engine is started. In the engine work machine according to the present invention, the work tool is a disk-shaped rotary tool for performing a cutting work of stone or concrete.

  According to the present invention, since the fuel in the fuel tank can be discharged to the recovery tube via the fuel supply tube, the carburetor, and the discharge tube by the pump operation of the fuel recovery pump, the fuel can be recovered. The fuel can be easily transferred without being inclined or lifted, and the workability of the fuel recovery operation can be improved.

  If the fuel recovery pump is provided with a bypass flow path, the fuel recovery operation can be automatically performed under its own weight under a state where the fuel is filled in the fuel supply tube, the carburetor, and the discharge tube. If the fuel recovery pump is provided with a return tube for returning the excess fuel discharged from the vaporizer to the fuel tank, the fuel recovery pump can also be used as a priming pump.

It is a front view which shows the engine cutter which is an example of an engine working machine. FIG. 3 is a partially cutaway perspective view schematically showing a fuel recovery mechanism provided in the engine cutter. (A)-(C) are sectional drawings of the fuel collection | recovery pump shown by FIG. 2, respectively. FIG. 4 is a partially cutaway perspective view showing a state in which fuel in a fuel tank is being collected in a fuel collection container. FIG. 5 is a front view of FIG. 4. It is a perspective view which shows roughly the working machine main body of the conventional engine cutter. It is sectional drawing of the working machine main body which shows the state which is transferring the fuel from the fuel tank shown in FIG. 6 to the fuel collection container. It is sectional drawing of the priming pump shown by FIG. 6 and FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. An engine cutter 10 shown in FIG. 1 has a work machine main body 12 on which an engine 11 is provided, and an arm 13 attached to the front side of the work machine main body 12 has a work for cutting stone or concrete. A rotating tool as a tool, that is, a disc cutter 14 is mounted. The disk cutter 14 is attached to a driven shaft 15 that is rotatably mounted on the distal end portion of the arm 13, and is provided on a driven pulley 17 provided on the drive shaft 16 that protrudes on the proximal end portion of the arm 13 and the driven shaft 15. A belt 19 is stretched around the driven pulley 18. The drive shaft 16 is connected to the crankshaft of the engine 11 via a centrifugal clutch (not shown), and the disk cutter 14 is rotationally driven by the crankshaft via a power transmission mechanism including a belt 19 and the like.

  A rear handle 21 is attached to the rear side portion of the work machine body 12 so as to protrude rearward, and a front handle 22 is attached to the front side portion so as to cross the work machine body 12. When an operator performs cutting work on the work material with the engine cutter 10, the rear handle 21 is gripped with one hand and the front handle 22 is gripped with the other hand to lift the engine cutter 10. The rear handle 21 is provided with a throttle lever 23 for adjusting the engine speed.

  A fuel tank 24 is incorporated in the lower part of the work machine body 12. In order to vaporize the fuel stored in the fuel tank 24 and supply it to the engine 11, the work machine body 12 is provided with a diaphragm type vaporizer 25. When fresh air purified by the air filter is supplied to the carburetor 25, fuel is injected into the fresh air to generate an air-fuel mixture, and the generated air-fuel mixture is supplied to the engine 11. A fuel tank cap 26 is detachably provided at a fuel filler opening provided in the work machine body 12 for injecting fuel into the fuel tank 24.

  As shown in FIG. 2, the work machine body 12 is provided with a fuel recovery mechanism 30, and FIG. 2 schematically shows the positional relationship among the fuel tank 24, the carburetor 25, and the fuel recovery mechanism 30. . The fuel tank 24 is provided with a fuel supply port 27 for injecting fuel from the outside, and a fuel tank cap 26 is detachably attached to the fuel supply port 27. An intake passage 28 is formed in the carburetor 25, and fuel is injected into the outside air that has been purified by a filter (not shown) and supplied to the intake passage 28. In order to supply the fuel in the fuel tank 24 to the carburetor 25, an oil supply tube 31 in which an oil supply passage is formed passes through the top wall of the fuel tank 24 and is connected to the carburetor 25. A filter 32 is provided at the tip of 31.

  The fuel recovery mechanism 30 includes a fuel recovery pump 33. The fuel recovery pump 33 is formed by a port block 34 as a pump base and a pump member 35 provided on the port block 34. In order to discharge the fuel supplied to the carburetor 25 from the carburetor 25, a discharge tube 36 having a discharge channel formed therein is connected to the carburetor 25. This discharge tube 36 is shown in FIG. In this way, it is connected to an inflow port 37 provided in the port block 34.

  A return port 39 provided with a return channel is connected to a return port 38 provided in the port block 34. The return tube 39 is used to return the fuel discharged to the discharge tube 36 after being supplied to the vaporizer 25 to the fuel tank 24. The oil supply tube 31, the discharge tube 36, and the return tube 39 are formed of hollow tubes such as metal and resin.

  As shown in FIG. 3, a recovery port 41 provided in the port block 34 has a recovery tube 42 with a recovery channel formed therein for discharging and recovering the fuel in the fuel tank 24 to the outside. Is connected. The recovery tube 42 is formed of a flexible material such as soft resin or rubber. As shown in FIG. 2, when the fuel recovery operation is not performed, a holder attached to the work machine main body 12 is used. 43 is held in a folded state.

  As shown in FIG. 3, the pump member 35 has a cylindrical mounting portion 35a fixed to the port block 34 and a tip portion 35b having an arcuate cross section integrated with the cylindrical mounting portion 35a. It is made of a flexible material. A pump chamber 44 is formed inside the pump member 35 by the pump member 35 and the port block 34. The pump chamber 44 contracts when the operator pushes the tip 35b of the pump member 35 by hand, and the tip 35b. When the hand is released, the pump chamber 44 expands due to the elasticity of the tip 35b.

  A discharge chamber 45 communicating with the pump chamber 44 is formed in the port block 34, and a return valve 46 is disposed between the pump chamber 44 and the discharge chamber 45. The return valve 46 is a composite valve having a first check valve 46a and a second check valve 46b. The first check valve 46a discharges fuel in the pump chamber 44 to the discharge chamber 45 when the pump chamber 44 contracts, and prevents back flow of fuel into the pump chamber 44 when the pump chamber 44 expands. On the other hand, the second check valve 46b sucks the discharge flow path of the discharge tube 36 to a negative pressure state when the pump chamber 44 expands, and if fuel exists in the discharge tube 36, the fuel is pumped into the pump chamber. Aspirate to 44. On the other hand, when the pump chamber 44 contracts, the reverse flow of the fuel into the discharge tube 36 is prevented.

  The port block 34 is formed with a bypass channel 47 that allows the inflow port 37 and the recovery port 41 to communicate with each other. As shown in FIG. 3 (B), the bypass passage 47 is blocked and the discharge passage in the discharge tube 36 communicates with the pump chamber 44 as shown in FIGS. 3 (A) and 3 (C). An inflow channel switching valve 51 is provided in the port block 34 in order to switch the discharge channel in the discharge tube 36 to a state of communicating with the recovery channel of the recovery tube 42 via the bypass channel 47. The inflow channel switching valve 51 is a manually operated three-way valve, and is switched to one of the two positions described above by manually operating the operation unit 51a shown in FIG.

  As shown in FIGS. 3A and 3B, the port block 34 has a state in which the pump chamber 44 communicates with the return flow path of the return tube 39 via the discharge chamber 45 as shown in FIG. In addition, a recovery flow path switching valve 52 is provided to switch the pump chamber 44 to a state where the pump chamber 44 communicates with the recovery flow path of the recovery tube 42 via the discharge chamber 45. The recovery flow path switching valve 52 is also a manually operated three-way valve, and can be switched to one of the two positions described above by manually operating the operation portion 52a shown in FIG.

  As described above, the fuel recovery mechanism 30 includes the fuel recovery pump 33, the return tube 39, and the recovery tube 42. The fuel recovery pump 33 supplies the fuel in the fuel tank 24 to the carburetor 25 when the engine is started. It has a function as a priming pump.

  When the fuel recovery pump 33 functions as a priming pump, the inflow channel switching valve 51 and the recovery channel switching valve 52 are operated to the positions shown in FIG. By operating each flow path switching valve, the discharge flow path of the discharge tube 36 communicates with the pump chamber 44 via the return valve 46, and the return flow path of the return tube 39 passes through the discharge chamber 45 and the return valve 46. A state communicating with the pump chamber 44 is set. At this time, the respective operation units 51a and 52a are set by manual operation at the positions shown in FIG. Under this state, after the pump member 35 of the fuel recovery pump 33 is pressed by an operator's manual operation and the pump chamber 44 contracts, when the pump member 35 is released, the pump member 35 is elastically deformed. As a result, the pump chamber 44 expands. Thereby, the fuel in the fuel tank 24 is sucked and supplied to the vaporizer 25 by the fuel supply tube 31.

  When emptying the fuel tank 24, the fuel in the fuel tank 24 is transferred to the fuel recovery container 53 using the recovery tube 42 as shown in FIGS. 4 and 5. When the fuel is transferred, the collection tube 42 is removed from the holder 43 and the tip of the collection tube 42 is inserted into the fuel collection container 53. Furthermore, the inflow channel switching valve 51 and the recovery channel switching valve 52 are operated to the positions shown in FIG. By operating each switching valve, the discharge flow path of the discharge tube 36 communicates with the pump chamber 44 via the return valve 46, and the recovery flow path of the recovery tube 42 is connected to the pump chamber via the discharge chamber 45 and the return valve 46. 44 is communicated. At this time, the respective operation units 51a and 52a are set by manual operation at the positions shown in FIGS. Under this state, when the pump member 35 of the fuel recovery pump 33 is pressed by an operator's manual operation and the pump chamber 44 contracts, the fuel in the pump chamber 44 is discharged to the recovery flow path of the recovery tube 42. The fuel is transferred to the fuel recovery container 53. On the other hand, when the pressing of the pump member 35 is released, the pump member 35 is elastically deformed to expand the pump chamber 44, and the fuel in the fuel tank 24 is pumped through the fuel supply tube 31, the vaporizer 25 and the discharge tube 36. Sucked into the chamber 44. As described above, by repeating the pressing operation and the pressing releasing operation of the pump member 35, the fuel remaining in the fuel tank 24 is transferred into the fuel recovery container 53 by the pump operation.

  When the fuel recovery container 53 can be installed at a position lower than the bottom surface of the fuel tank 24, the fuel is filled from the oil supply passage of the fuel supply tube 31 to the recovery passage of the recovery tube 42. The fuel filled in these flow paths can be transferred into the fuel recovery container 53 by its own weight by the siphon principle. At that time, the inflow channel switching valve 51 is operated to the position shown in FIG. As a result, the discharge flow path of the discharge tube 36 communicates with the recovery flow path of the recovery tube 42 via the bypass flow path 47, and the fuel remaining in the fuel tank 24 without operating the pump member 35. Can be transferred to the fuel recovery container 53 by its own weight. Thus, if the bypass flow path 47 is provided, the fuel recovery operation can be easily performed.

  The fuel recovery pump 33 described above has a configuration in which the bypass block 47 is provided in the port block 34. However, in the configuration in which all the fuel in the fuel tank 24 is transferred to the fuel recovery container 53 by the pump operation, the bypass is provided. The flow path 47 and the inflow flow path switching valve 51 are not provided. Even in this configuration, the fuel recovery is performed by switching the discharge passage 45 to either the position where the discharge chamber 45 communicates with the return passage of the return tube 39 or the position where the discharge chamber 45 communicates with the collection tube 42. The pump 33 can also function as a priming pump and a fuel transfer pump.

  The fuel recovery pump 33 shown also functions as a priming pump as described above. On the other hand, in the form not having the function of the priming pump, the return tube 39 and the recovery flow path switching valve 52 are not provided. In that form, the recovery flow path of the recovery tube 42 is always in communication with the discharge chamber 45. Even in such a form, there are a form in which the bypass flow path 47 is provided and a form in which the bypass flow path 47 is not provided. In the form in which the fuel recovery pump 33 does not have the function of the priming pump, the priming pump is separated from the fuel recovery pump 33 and provided in the work machine main body 12, so that the installation space for both is increased. On the other hand, since the fuel recovery pump 33 described above has the function of a priming pump, both functions can be achieved in a small space.

  FIG. 6 is a perspective view showing a conventional work machine body 12a, and FIG. 7 is a side view showing a state where the fuel is transferred from the fuel tank 24 of the conventional work machine body 12a to the fuel recovery container 53. FIG. 8 is a sectional view showing the priming pump 54 shown in FIGS. 6 and 7. In these drawings, the same reference numerals are given to members having commonality with the above-described embodiment. In the conventional engine work machine, in order to transfer the fuel in the fuel tank 24 from the fuel supply port 27 to the fuel recovery container 53, the fuel supply port 27 is located on the side surface or the upper surface of the engine work machine. The machine will be lifted and tilted as shown in FIG. It is necessary to prevent the fuel from leaking from the fuel recovery container during fuel recovery, and the fuel recovery operation cannot be performed easily. On the other hand, by providing the fuel recovery mechanism 30 including the fuel recovery pump 33 in the engine operation, the workability of the fuel recovery operation from the fuel tank 24 of the engine working machine, that is, the fuel transfer operation is improved.

  As described above, when the fuel recovery pump 33 does not have the function of the priming pump, the priming pump 54 shown in FIG. 8 is separated from the fuel recovery pump 33 and attached to the work machine body 12. Although the illustrated fuel recovery pump 33 recovers the fuel in the fuel tank 24 via the carburetor 25, the fuel in the fuel tank 24 is directly discharged outside without passing through the carburetor 25. Anyway.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, FIG. 1 shows an engine cutter 10 as an engine working machine. However, not only the engine cutter but also an engine working machine that drives a work tool such as a rotary tool using the engine as a driving source, a brush cutter, The present invention can also be applied to a chain saw, a trimming machine, a blower, and the like.

  DESCRIPTION OF SYMBOLS 10 ... Engine cutter, 11 ... Engine, 12 ... Work machine main body, 13 ... Arm, 14 ... Disc cutter, 15 ... Drive shaft, 16 ... Drive shaft, 17, 18 ... Pulley, 19 ... Belt, 21 ... Rear handle, 22 DESCRIPTION OF SYMBOLS ... Front handle, 23 ... Throttle lever, 24 ... Fuel tank, 25 ... Vaporizer, 26 ... Fuel tank cap, 27 ... Refueling port, 28 ... Intake passage, 30 ... Fuel recovery mechanism, 31 ... Refueling tube, 32 ... Filter, 33 ... Fuel recovery pump, 34 ... Port block, 35 ... Pump member, 36 ... Discharge tube, 37 ... Inflow port, 38 ... Return port, 39 ... Return tube, 41 ... Recovery port, 42 ... Recovery tube, 43 ... Holder, 44 ... Pump chamber, 45 ... Discharge chamber, 46 ... Return valve, 47 ... Bypass flow path, 51 ... Inflow flow path switching valve, 51a ... Operating section, 5 ... recovery channel switching valve, 52a ... operation unit, 53 ... fuel collecting container, 54 ... priming pump.

Claims (6)

An engine working machine that drives a work tool using an engine as a drive source,
A working machine main body provided with the engine and a fuel tank for storing fuel supplied to the engine;
An engine working machine comprising a fuel recovery pump for discharging the fuel in the fuel tank to the outside.   A vaporizer for vaporizing the fuel in the fuel tank supplied by the fuel supply tube is provided in the working machine main body, a discharge tube for discharging the fuel from the vaporizer, and a recovery tube provided to protrude to the outside of the working machine main body The engine working machine according to claim 1, wherein the fuel recovery pump is provided between the fuel tank and the fuel in the fuel tank is discharged from the recovery tube to the outside through the carburetor.   The fuel recovery pump has an elastically deformable pump member having an expandable and contractible pump chamber communicating with the flow path of the discharge tube and the recovery tube, and flows out of the vaporizer into the discharge tube due to elastic deformation of the pump member. The engine working machine according to claim 2, further comprising a return valve that discharges the spent fuel to the recovery tube.   An inflow flow path switching valve for switching between a state in which the flow path of the discharge tube communicates with the pump chamber and a state in which the flow path of the discharge tube communicates with the recovery tube via a bypass flow path; The engine working machine according to claim 3, wherein the fuel filled in the recovery tube is discharged from the recovery tube to the outside through the bypass flow path by its own weight.   A return tube for returning the fuel discharged from the pump chamber to the fuel tank; a state in which the pump chamber communicates with a flow path in the return tube; and a state in which the pump chamber communicates with a flow path in the recovery tube. The engine working machine according to claim 3 or 4, further comprising a recovery flow path switching valve for switching, wherein the fuel recovery pump is also used as a priming pump for supplying fuel to the carburetor when the engine is started.   The engine work machine according to any one of claims 1 to 5, wherein the work tool is a disk-shaped rotary tool for performing a cutting work of stone or concrete.

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