JP3002655U - Fuel Return Mechanism of Circulating Vaporizer for Portable Engine - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents the fuel in the fuel tank from flowing back to the circulating carburetor when the mobile engine is tilted and stored.
Prevent the fuel from flowing out of the carburetor. A recoil starter 3 is attached to one end of a drive shaft 2 of an engine, a centrifugal clutch 4 is attached to the other end of the engine, and a fuel tank 7 is attached to the lower side of the engine. In a portable engine to which the carburetor 6 is attached, the return pipe 28 of the circulatory carburetor is used when the centrifugal clutch is in an upright position and when the engine is in an upright position, and the circulatory carburetor is on the lower side around the drive shaft. Connect to a position above the liquid level in the tank in both postures.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel return mechanism for a circulation type carburetor used in portable engines such as brush cutters, chain saws, and power sprayers.

[0002]

[Prior art]

 The circulating carburetor sucks fuel from the fuel tank by the fuel pump and supplies it to the fuel chamber, and when the oil level in the chamber reaches a predetermined height, the fuel overflows to form a constant oil level. The fuel that overflows from the tank is returned to the fuel tank through the return passage.

[0003]

[Problems to be solved by the device]

 The return passage is connected to the fuel tank by a return pipe, and the return passage and the return pipe are generally arranged in a substantially straight line to enhance the dischargeability as disclosed in Japanese Utility Model Laid-Open No. 62-97256. Has been done.

However, in the circulation type vaporizer in which the return pipe is arranged in this way, it is used in a working machine such as a brush cutter, which hooks the teeth at the tip or hooks the teeth upward and leans against the wall. If the fuel tank is almost full and the circulation type carburetor is below the liquid level in the tank, the fuel in the tank will return to the return pipe. After that, there is a problem that it flows back to the carburetor and then flows out from the air vent passage of the carburetor.

Further, even when the engine is tilted around the drive shaft so that the circulation type carburetor is on the lower side, the fuel tank is almost full and the circulation type carburetor is located above the liquid level in the tank. If it is on the lower side, the fuel in the tank will flow back to the carburetor through the return pipe, and will flow out from the air vent passage of the carburetor to the outside.

The present invention aims to prevent the fuel in the fuel tank from flowing back to the circulating carburetor when the portable engine is tilted and stored, and to prevent the fuel from flowing out of the carburetor. .

[0007]

[Technical means for solving problems]

 According to the present invention, a recoil starter is attached to one end of a drive shaft of an engine, a centrifugal clutch is attached to the other end thereof, a fuel tank is attached to the lower side of the engine, and a circulation type carburetor is attached in a direction substantially orthogonal to the drive shaft. In a portable engine, the return pipe of the circulatory carburetor is installed both when the engine is upright with the centrifugal clutch above and when the engine is horizontal with the circulatory carburetor below the drive shaft. It is characterized in that it is connected to a position above the liquid level in the tank in the posture.

[0008]

[Action]

 According to the above configuration, when the centrifugal clutch side is on the upper side, the connection part of the return pipe to the fuel tank is located on the liquid level in the tank, and the reverse flow of fuel from the return pipe to the carburetor occurs. To be prevented.

Even when the engine is tilted toward the circulation carburetor side about the drive shaft, the connection part of the return pipe to the fuel tank is located on the liquid level in the tank, and the return pipe is connected to the carburetor. Backflow of fuel into the chamber is prevented.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 is an explanatory view of the return mechanism of the present invention seen from the upper side of the engine, FIG. 2 is an explanatory view of the return mechanism of the present invention seen from the centrifugal clutch side, FIG. In the present invention, an explanatory view showing a state in which the engine drive shaft is inclined toward the circulation type carburetor side, and FIG. 5 is an explanatory view showing a state in which the centrifugal clutch side is inclined upward in the present invention.

Reference numeral 1 denotes an engine body, which is provided with a crankshaft (hereinafter, referred to as a drive shaft) 2 which is connected to a piston (not shown) and rotates. A recoil starter 3 is attached to one end of the drive shaft 2 and a centrifugal clutch 4 is attached to the other end. On the other hand, an intake port (not shown) is provided on one side of the engine in a direction substantially orthogonal to the drive shaft 2, and a circulation type carburetor 6 is attached to the intake port. A fuel tank 7 is attached to the bottom of the engine 1.

An intake passage 12 is provided in the body 11 of the circulation type carburetor 6, the upstream side of the intake passage 12 is connected to an air cleaner (not shown), and the downstream side is connected to the intake port. A throttle valve 13 is provided in the intake passage 12 so as to be capable of advancing and retracting in a substantially orthogonal direction, and the effective diameter of the intake passage 12 is controlled.

A fuel chamber 16 is formed below the intake passage 12 by the carburetor body 11 and the chamber case 15, and a main nozzle boss 17 is projected from the body 11 into the fuel chamber 16. . The main nozzle boss 17 is provided with a main nozzle accommodating hole 19, and the main nozzle 20 is accommodated in the accommodating hole 19 and is fixed by a main jet 21 screwed to the lower end of the boss 17. The upper end opening of the main nozzle 20 faces the intake passage 12, and the lower end opening communicates with the lower surface of the fuel chamber 16 via the main jet 21. A jet needle 23 is suspended from the throttle valve 13, and the tip side of the jet needle 23 is inserted into the main nozzle 20 to control the opening area of the main nozzle 20 as the throttle valve 13 advances and retracts. ing.

A return passage 25 is provided at a side portion of the fuel chamber 16, and a weir 26 having a prescribed oil surface height is provided between them. A wire 27 is disposed between the fuel chamber 16 and the return passage 25. The wire 27 constantly discharges a small amount of fuel from the fuel chamber 16 to the return passage 25, and automatically after the engine is stopped. Empty the fuel chamber 16.

The return passage 25 is connected to the fuel tank 7 via a return pipe 28, and an air vent passage 30 for introducing atmospheric pressure is opened in an upper air layer of the return passage 25. The return pipe 28 is located above the liquid level in the tank when the engine is upright with the centrifugal clutch 4 on the upper side and when the engine is tilted toward the circulation carburetor 6 side around the drive shaft 2 in both postures. It is connected to the fuel tank 7 in the upper position. As an example, if the return pipe 28 is connected to the drive shaft 2 on the opposite side of the circulation type carburetor 6 and to the corner portion 7a of the fuel tank on the centrifugal clutch 4 side or in the vicinity thereof, the return pipe 28 will be in an upright position. Even when the engine is tilted to the carburetor side around the drive shaft 2 and the drive shaft 2, the connection portion between the return pipe 28 and the fuel tank 7 is always above the liquid level in the tank, and the carburetor in this posture is Backflow of fuel is prevented.

The circulation type carburetor 6 is provided with a fuel pump 35 driven by the operating pressure of the engine. The fuel pump 35 is a conventionally well-known diaphragm pump composed of a pump diaphragm 36 and a pair of check valves 37 and 38. The fuel pump 35 applies an operating pressure of the engine to a pressure chamber 39 formed on one side of the pump diaphragm 36. By virtue of this, the pump diaphragm 36 is vibrated, and fuel is sucked from the fuel tank 7 through one check valve 37 into the pump chamber 40 formed on the other side of the pump diaphragm 36, and the other check valve 38. Is sent to the fuel chamber 16 via the fuel passage 41. When the oil level in the fuel chamber 16 reaches the height of the weir 26, the fuel in the fuel chamber 16 overflows into the return passage 25 to form a constant oil level H.

A priming pump 43 that can be manually pressed is provided on the outer surface of the carburetor 6, and a pump chamber 44 of the pump is connected to a pump chamber 40 of a fuel pump 35. Therefore, when the priming pump 43 is repeatedly pressed, the fuel in the fuel tank 7 is supplied to the fuel chamber 16 in cooperation with the check valves 37 and 38 of the fuel pump 35.

The operation of the above embodiment will be described below. According to the above structure, when the centrifugal clutch 4 side is in the upper position, the connecting portion 7a of the return pipe 28 to the fuel tank 7 is located on the liquid level in the tank, and the return pipe 28 to the carburetor 6 is connected. Backflow of fuel into the chamber is prevented.

Even when the engine is tilted toward the circulation carburetor side about the drive shaft 2, the connecting portion 7a of the return pipe 28 to the fuel tank 7 is located on the liquid level in the tank, and the return Backflow of fuel from the pipe 28 to the carburetor is prevented.

[0020]

[Effect of device]

 As described above in detail, according to the present invention, the fuel in the conventional fuel tank can be prevented when the engine is upright with the centrifugal clutch above and when the engine is tilted toward the circulation carburetor side around the drive shaft. The fuel tank connection part of the return pipe of the circulation type vaporizer is located above the liquid level in the tank in the inclined direction in which it flows backward to the vaporizer and easily leaks to the outside, so that the fuel is prevented from flowing into the pipe. Fuel does not flow out of the vaporizer.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a return mechanism of the present invention.

FIG. 2 is an explanatory view of the return mechanism of the present invention seen from the centrifugal clutch side.

FIG. 3 is a vertical cross-sectional view of the circulation type vaporizer of the present invention. .

FIG. 4 is an explanatory view showing a state in which the engine drive shaft is inclined toward the circulation type carburetor side in the present invention.

FIG. 5 is an explanatory view showing a state in which the centrifugal clutch side is inclined upward in the present invention.

[Explanation of symbols]

 1 Engine 3 Recoil Starter 4 Centrifugal Clutch 6 Circulating Vaporizer 7 Fuel Tank 16 Fuel Chamber 25 Return Passage 28 Return Pipe

Claims (2)

[Scope of utility model registration request] 1. A recoil starter is attached to one end of a drive shaft of an engine, a centrifugal clutch is attached to the other end of the engine, and a fuel tank is attached to the lower side of the engine, and a circulation type carburetor is provided in a direction substantially orthogonal to the drive shaft. In a portable engine to be mounted, the return pipe of the circulation type carburetor is placed in both postures when the engine is upright with the centrifugal clutch above and when the engine is overturned with the circulation type carburetor below with the drive shaft as a center. A fuel return mechanism for a circulation carburetor for a portable engine, which is connected to a position which is sometimes higher than the liquid level in the tank. 2. The return pipe is connected to a corner portion of a fuel tank on the side opposite to the circulating carburetor with respect to the drive shaft and on the centrifugal clutch side. Fuel return mechanism of circulating carburetor for portable engine.