JPS6135719Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an idle adjustment device that prevents unauthorized adjustment of the idle adjustment screw of a carburetor by anyone other than a specific person.

The slow system of the carburetor will be explained with reference to FIG.

1 is the intake cylinder of the carburetor, 2 is the throttle valve,
3 is the slow system mixture passage, 4 is the slow port,
5 is an idle port, 6 is an idle adjusting screw, and 7 is a spring for preventing loosening of the screw 6. In a conventional carburetor, as shown in FIGS. 2 and 3, a cylindrical screw head 6a with a flathead screwdriver groove 8 on its top surface has a groove width of the screwdriver groove 8 on the top plate and a side length approximately equal to the width of the screwdriver groove 8 on the top plate. The cap 9, which has two equal square holes 9a in its diametrical direction, is fitted over the cap 9, and its edge 9b is bent inward and squeezed to rotatably lock on the bottom of the screw head 6a. As shown in FIG. 4, using a special tool 10 with two protruding pins of rectangular cross section, insert the tips of the two pins of this tool into the slotted screwdriver groove 8 through the square hole 9a, together with the cap 9. The screw 6 is rotated and adjusted, and is a mechanism that can only be adjusted using this special tool 10.

However, with the above mechanism, if the threaded part of the idle adjuster screw 6 is long, the idle adjuster screw 6 can be rotated by grasping the spring 7 part with pliers and turning it, and appropriate adjustments can be made by general users. This caused problems such as an increase in exhaust gas and engine malfunctions.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional device, and to provide a simple assembly.Moreover, assembly and idle adjustment are extremely easy if special tools are used, but adjustment is difficult without such tools. Therefore, it is an object of the present invention to provide an idle adjustment device that eliminates problems such as an increase in polluting exhaust gas and engine malfunction caused by a general user adjusting the idle adjustment screw as appropriate.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Here, the same or equivalent components as those of the conventional device will be described using the same reference numerals.

In a gasoline engine, at low speeds and low loads, the opening degree of the throttle valve is small, so the amount of air is small and the negative pressure in the ventilator (not shown) is small, making the supply of gasoline from the main nozzle uncertain.
Therefore, as shown in Fig. 5, if an idle port 5 is provided on the wall facing the edge of the throttle valve 2, a large negative pressure will be generated downstream of the valve when the throttle valve 2 is closed. Gasoline can be easily sucked out using the However, when the opening degree of the throttle valve 2 increases, the negative pressure in the intake pipe decreases, so that the injection of gasoline from the idle port 5 stops. The carburetor passage that operates only when the throttle valve 2 is close to fully closed is called a slow system. The fuel in this slow system supplies the engine with a mixture of a concentration necessary for low-speed operation, and this mixture ratio can be further finely adjusted by an idle adjust screw 6. This screw 6 is provided so that the engine can run smoothly even when idling, and this screw allows the tapered needle valve 6b at the tip of the idle adjustment screw 6 to be moved in and out.
The amount of fuel coming out of the idle port 5 can be finely adjusted.

Note that while the throttle valve 2 is further opened from the idling state and fuel is not yet sucked out from the main nozzle, fuel is mainly supplied from the slow port 4 to the air-fuel mixture. The slow port 4 is constructed so that the effective area of the port 4 increases as the throttle valve 2 opens, thereby smoothly switching the supply of air-fuel mixture from the slow system to the main system.

In the first embodiment of this invention, as shown in FIGS. 5 and 6, a hole with an oval cross section is formed on the top surface of the cylindrical screw head 11 of the idle adjustment screw 6 so that the dealer does not disturb the idle adjustment. 12, and the idle adjustment screw 6 can be adjusted only by a rod-shaped special tool 13 as shown in FIG. 7 that engages with the hole 12. Furthermore, on the outside of the idle adjustment screw 6, as shown in FIG. A cylindrical cap 16 having a diameter of 15 is fitted. Furthermore, the annular protrusion 15 has an inner diameter smaller than the outer diameter of the washer 17 and the screw head 11
It has a thickness that allows it to be loosely fitted between the bottom surface of the washer 17 and the washer 17. To assemble the idle mixture adjustment device of the present invention, insert the cylindrical cap 16 from the nozzle 6b side of the idle adjusting screw 6, and then insert it into the screw hole of the entire carburetor via the washer 17 and locking spring 7. It is only necessary to screw in the screw 6 using the special tool 13 and adjust the idling, and assembly can be completed extremely easily.

Since the annular projection 15 of the cylindrical cap 16 is loosely fitted between the bottom surface of the screw head 11 and the washer 17, even when the cylindrical cap 16 is rotated, it does not rotate idly relative to the idle adjustment screw 6. Since the screw head 11 and threaded portion are covered with a cylindrical cap 16, general users who do not use this tool cannot make appropriate adjustments as in conventional devices.

What is shown in FIGS. 8 to 10 is the second embodiment of the present invention.
In the first embodiment, a hole 12 with an elliptical cross section was provided on the top surface of the screw head 11 of the idle adjuster screw 6, whereas a projection 12a with an elliptical cross section was provided.
A special tool 13a used for this is provided.
The only difference is that the shape of the engaging portion is changed from an elliptical pin to an elliptical hole, and its operation and effect are exactly the same as in the first embodiment. The elliptical holes and elliptical protrusions on the upper surfaces of the screw heads 12, 12 are not limited to having an elliptical cross section, and may have any shape as long as they cannot be rotated without a special tool.

As described above, according to the idle adjustment device for a carburetor according to the present invention, an engaging portion for a special tool is provided on the upper surface of the idle adjusting screw head,
A cylindrical cap having an inner diameter slightly larger than the outer diameter of the screw head and having an annular protrusion projecting inward at the center of the inner peripheral surface is applied to the biasing force of the loosening prevention spring by the idle adjusting screw. When tightening against resistance, the annular projection is configured to fit loosely between the bottom surface of the screw head and the washer, so assembly is extremely easy, and the cylindrical cap can be rotated. Since the screw just rotates idly relative to the screw and does not fall out, and the screw head and threaded portion are completely covered, idle adjustment is extremely easy using a special tool. This idle adjustment device has an excellent effect in that it can completely prevent adjustment by the user and eliminate the increase in polluting exhaust gas and engine malfunction caused by the user adjusting the idle adjustment screw appropriately. are doing.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional explanatory diagram of the slow system and idle adjuster screw part of the carburetor, Figure 2 is a vertical cross-sectional view of a conventional idle adjustment device, Figure 3 is a front view of the same as above, and Figure 4 is a special tool of the same as above. front view, 5th
7 to 7 show a first embodiment of the carburetor idle adjustment device according to the present invention, FIG. 5 is a vertical sectional view of the carburetor slow system and the idle adjustment device, and FIG. 6 is the idle adjustment device. A front view of the device, Figure 7 is a front view of the same special tool as above, a side view of B, and Figure 8 is a front view of the device.
The figure is a longitudinal cross-sectional view of the second embodiment, FIG. 9 is a front view of the same, and FIG. 10 is a front view and a side view of the special tool. 6...Idol Asiast Screw, 11...
...screw head, 12, 12a...engaging part,
13, 13a... Special tool, 14... Cylindrical body, 15
... Annular projection, 16 ... Cylindrical cap.

Claims (1)

[Scope of utility model registration request] An idle adjusting screw, which has an engagement part for a special tool formed on the upper surface of the screw head and rotates together with the rotation of this special tool; a washer disposed to be spaced from the bottom; a locking spring interposed between the washer and the carburetor body into which the idle adjusting screw is screwed together; and a locking spring interposed between the washer and the idle adjusting screw. A cylindrical body formed with an inner diameter slightly larger than the outer diameter of the head and covering the screw head and the spring part, and a cylindrical body formed at the center of the inner circumferential surface of the cylindrical body and formed between the washer and the screw head. An idle adjusting device comprising: a cylindrical cap having an annular protrusion that fits loosely between the washer and has an inner diameter smaller than the outer diameter of the washer.