JPH0338416Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a small portable two-stroke engine equipped with a diaphragm carburetor.

(Prior Art) A small portable two-stroke engine equipped with a diaphragm carburetor has been widely used as a drive source for portable working machines such as brush cutters.

This small portable 2-stroke engine is
A common structure is that the fuel tank is disposed in the lower part, and when starting the engine, a priming pump is operated to suck up fuel from the fuel tank to the carburetor.

That is, to explain based on FIG. 9, the priming pump 91 forces fuel from the fuel tank 92 located below to the pulse pump 93, and the taker lever 94 is operated to control the fuel control valve 95 and the overflow. aisle 9
6 is opened, and at the same time as the fuel that has filled up in the metering chamber 97 begins to be supplied to the nozzle part 98, after confirming that the fuel has reached the overflow pipe 99, the recoil starter is activated,
The engine was starting.

(Problems to be Solved by the Invention) As described above, in the conventional two-stroke engine equipped with a priming pump, it is necessary to operate the takera lever together with the priming operation at the time of starting. The structure must be designed to prevent overflow and at the same time allow the fuel supply to be confirmed from the outside, resulting in a complicated structure and the inconvenience of increasing the overall cost of the engine due to the installation of an expensive priming pump. Was.

In addition, for users who do not like the complicated operation of operating the Teikura lever at the same time as the priming operation, there is also a method that sucks up fuel only by the suction effect of a pulse pump that utilizes pressure changes in the crankcase permanently installed in the diaphragm carburetor. However, in this case, there is the inconvenience of having to significantly increase the number of times the recoil is pulled, especially at the initial start-up after being left unused for a long time.

Alternatively, it is possible to arrange the fuel tank above the diaphragm carburetor so that fuel always flows down from the fuel tank to the diaphragm carburetor. The advantages of placing the fuel tank in the diaphragm carburetor are that it lowers the center of gravity of the engine, improving stability and workability, and that the fuel tank is located below the diaphragm carburetor, which prevents fuel from flowing to the carburetor when placed naturally. Since there is no fuel pot, there is no need for a fuel pot, and the advantages such as being able to prevent fuel overflow from the carburetor due to the user forgetting to tighten the fuel pot are lost.

This invention was created in consideration of these points,
The engine can be installed in a position where the fuel tank is normally located at the bottom, lowering the engine's center of gravity, and eliminating the need for a fuel tank. Diaphragm carburetor type small portable 2 that can be installed in a position where fuel flows down from the fuel tank to the carburetor during startup, making it easy to start the engine without a priming pump.
The purpose is to provide cycle engines.

(Means for solving the problem) In order to achieve the above object, the solution of the present invention is a small portable two-stroke engine equipped with a diaphragm carburetor and a fuel tank located at the lower part of the engine. The premise is that there is a standard support means for stably installing the engine in a standard position in which the fuel tank is located at the lower part of the engine, and in a non-standard position in which fuel flows from the fuel tank to the diaphragm carburetor. The engine shall be equipped with auxiliary support means to stabilize and install the engine.

(Function) With the above configuration, the engine is stably installed in the standard position with the fuel tank located at the bottom during normal operation (normal operation, stoppage, etc.), thereby lowering the center of gravity of the engine and improving stability and workability. Improvement is ensured and fuel consumption becomes unnecessary. On the other hand, at the time of starting, the engine can be started easily by stably installing the engine in a non-standard position where fuel flows down from the fuel tank to the diaphragm carburetor.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 1 shows the diaphragm carburetor type 2 of this invention.
A front view showing the first embodiment of the cycle engine, FIG. 2 is a right side view of the same embodiment, FIG. 3 is a sectional view of the diaphragm carburetor of the same embodiment, and FIG. 4 is an auxiliary support means of the same embodiment. FIG. 5 is a partially cutaway front view showing the recoil starter of the same embodiment, FIG. 6 is a view taken in the direction shown in FIG. 5, and FIG. 7 is an engine equipped with the same embodiment. FIG. 1 is a perspective view showing an example of a portable working machine.

As shown in FIGS. 1 to 3, the diaphragm carburetor type small portable two-stroke engine 1 of this embodiment has a diaphragm carburetor 2 installed in the upper part of the engine, and a fuel tank 3 in the lower part of the engine. is installed.

The diaphragm carburetor 2 is disposed between the air cleaner 4 and the engine cylinder 5, and has a pulse pump 23 that supplies fuel in the fuel tank 3 to the nozzle section 22 through a conduit 21, and a spring 27 to control the amount of fuel to be supplied. Control unit 2 to control
4, a bench lily portion 25 that atomizes fuel from the nozzle portion 22, and a throttle valve 26.
The throttle valve 26 includes an engine speed control lever 1.
1 is connected to the control cable 12. 3
0 is a correction mechanism when the valve of the control unit 24 is stuck.

A pair of shoe clutches 9 connected to a crankshaft (not shown) are disposed on the front output side of the engine 1, and are connected to a portable working machine 10 (such as a brush cutter) together with a support 7 via a flange 6. (see Figure 7) is fitted into the input end clutch case.

As shown in FIGS. 1 and 4, the flange 6 has a diaphragm carburetor 2 in an upright state, that is, when it is installed in a portable working machine 10.
A standard support means 71 consisting of a stand for stably installing the engine 1 in a standard engine position in which the fuel tank 3 is located at the top and the fuel tank 3 is located at the bottom, and a 90° sideways position (non-standard position) where the air cleaner 4 is located at the bottom. A support body 7 is provided which is integrally welded with an auxiliary support means 72 consisting of a stand for stably installing the engine 1, and the support body 7 is fastened to the clutch portion of the portable working machine 10 together with the flange 6. be done. Both stands 71 and 72 are
It is made from a steel rod bent into a trapezoidal shape with an expanded ground contact area. In addition to steel rods, the stands 71 and 72 may be plate-shaped as long as they have appropriate rigidity, or may be made of plastic or the like. Furthermore, in this embodiment, the support body 7 is fastened together with the engine 1 to the working machine 10, but the standard support means 71 and the auxiliary support means 72 are separately attached to the engine 1 by, for example, bolting. Alternatively, it may be provided on the working machine 10 side as long as it performs the same function.

In this embodiment, on the rear side of the engine 1, there is a recoil starter 8 connected to the crankshaft.
It is assembled with the pull handle 84 protruding upward. As shown in FIGS. 5 and 6, the pull-out portion 83 of the rope 82 provided on the casing 81 of the recoil starter 8 has a smooth curvature so that the engine 1 can be easily started even in the sideways position. A guide means 85 consisting of a groove is formed. Note that the guide means 85 is not necessarily required as long as the drawer portion 83 has a structure that allows the rope 82 to be pulled smoothly even when the engine is in a sideways position.

Next, the diaphragm carburetor type 2 of this example
The starting operation of the cycle engine 1 will be outlined.

When installed in the portable working machine 10, the engine 1 is installed by the auxiliary support means 72 in a 90° horizontal position with the air cleaner 4 facing downward. In this sideways state, fuel flows down and is supplied by gravity from the fuel tank 3 to the pulse pump 23 of the diaphragm carburetor 2.
Therefore, the conventional priming pump P shown in phantom lines in FIGS. 1 and 2 can be omitted. The pulse pump 23 is connected to the recoil starter 8
By operating the nozzle section 22, a pressure pulse within the crankcase (not shown) is received and fuel is supplied to the nozzle section 22. Therefore, unlike in the past, the priming pump does not supply more fuel than necessary, and the conventional series of structures for overflow prevention and fuel supply confirmation are also no longer necessary.

In this embodiment, the rope 82 of the recoil starter 8 is
The guide means 85, which is a curved groove formed in the drawer part 83, has low sliding resistance, so that the user can easily pull the pull handle 84. Therefore, even when the engine 1 is in the sideways position, the user can easily start the engine 1 after turning on the electrical system switch S.
Once engine 1 is started, the next engine 1
The restart is performed in the standard position within a time period in which the fuel that has reached the pump 23 does not return to the tank 3. Engine 1 is stopped by turning switch S to OFF.

Next, a second embodiment of the present invention will be described based on the front view shown in FIG.

In this embodiment, the right side surface of the air cleaner cover 15 and the upper surface of the inlet cap 3a of the fuel tank 3 are flush with each other in the vertical direction to constitute the auxiliary support means 72a. The effects obtained are the same as in the first embodiment. The right side surface of the air cleaner cover 15 and the top surface of the cap 3a do not necessarily have to be flat as long as the engine can be installed with sufficient stability even in a horizontal position.

Above, we have described the case where the engine is started with the engine tilted sideways at 90 degrees, but this invention proposes that if fuel flows down from the fuel tank to the carburetor, the engine can be started in a position other than tilted sideways, for example, turned 180 degrees. It is also possible to construct the starter with auxiliary support means and rope guide means for the recoil starter to enable starting even after installation.

The reason why the engine is not configured to operate in the non-standard position even after starting is that the heavy fuel tank is placed horizontally, resulting in an unstable position, and the center of gravity changes due to fluctuations in the amount of fuel. This is because the balance of the engine as a whole becomes very poor, so by adopting the standard position, the center of gravity of the engine can be lowered and stability and workability can be improved.

Also, when the engine is stopped and left for a long time, the reason why the engine is not placed in a non-standard position is to avoid the need to install a new means to prevent fuel from flowing down to the carburetor, such as a fuel tank. It is.

As described above, in the diaphragm carburetor type two-stroke engine of the present invention, the fuel tank is located below the engine as before during normal work and when the work equipment is stopped and left unattended.
The engine assumes the most stable position. Also, even in a non-standard position where fuel flows down to the carburetor only during startup, especially during initial startup after a long stop,
This makes it easier to start the engine.

(Effects of the invention) As described above, according to the diaphragm carburetor type two-stroke engine of the invention, the engine can be normally installed in the standard position with the fuel tank located at the bottom, thereby lowering the center of gravity of the engine and stabilizing it. This ensures good performance and workability, and eliminates the need for a fuel tank. At the time of starting, the engine can be stabilized in a position where fuel flows from the fuel tank to the diaphragm carburetor, and the engine can be installed in a position with good fuel supply conditions, making it easy to install. The engine can be started.

In addition, it is possible to eliminate the expensive priming pump and structure for preventing carburetor overflow and checking fuel supply that were conventionally used when starting the engine in an upright position, making it easier to start the engine. structure, it is possible to reduce costs.

[Brief explanation of the drawing]

Figure 1 shows the diaphragm carburetor type 2 of this invention.
Plan view showing an example of a cycle engine, 2nd
3 is a sectional view of the diaphragm carburetor of the same embodiment, FIG. 4 is a perspective view showing the auxiliary support means of the same embodiment, and FIG. 5 is a recoil coil of the same embodiment. FIG. 6 is a partially cutaway front view showing the starter, FIG. 6 is a view taken in the direction shown in FIG. 5, FIG. 7 is a perspective view showing a portable working machine equipped with an engine according to the same embodiment, and FIG. FIG. 7 is a front view showing another embodiment with different means. FIG. 9 is a sectional view showing a conventional example of a diaphragm carburetor type two-stroke engine. 1...Diaphragm carburetor type 2-stroke engine, 2...Diaphragm carburetor, 3...
Fuel tank, 7... Support, 71... Standard support means, 72... Auxiliary support means, 72a... Auxiliary support means, 8... Recoil starter, 82... Rope, 83... Drawer part, 85... Guidance means.

Claims (1)

[Scope of Claim for Utility Model Registration] In a small portable two-stroke engine equipped with a diaphragm carburetor and with a fuel tank located at the lower part of the engine, the engine is in a standard position with the fuel tank located at the lower part of the engine. The engine is characterized by comprising standard support means for stably installing the engine, and auxiliary support means for stably installing the engine in a non-standard position in which fuel flows down from the fuel tank to the diaphragm carburetor. A diaphragm carburetor type 2-stroke engine.