JP3728001B2 - How to remove the operation restriction cap of the fuel regulating valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to an operation restriction device for restricting the rotation of a fuel adjustment valve in a fuel amount increasing direction in a carburetor of a small internal combustion engine mounted on a portable working machine such as a power saw or a brush cutter, and more particularly a fuel adjustment valve. The present invention relates to an extraction tool for an operation restriction cap that fits into a selection.
[0002]
[Prior art]
As the exhaust gas components are regulated even in small internal combustion engines, it is necessary to take measures so that the fuel adjustment valve of the carburetor cannot be adjusted in the direction exceeding the amount of fuel adjusted at the manufacturing plant of the internal combustion engine. is there.
[0003]
Therefore, the present applicant previously filed an application relating to the operation restriction device for the fuel regulating valve in the carburetor according to Japanese Patent Application No. 7-145677. In the fuel regulating valve operation restriction device according to the above application, the fuel regulating valve is completely built in the protruding wall portion of the carburetor body and is covered with a sealing plate that cannot be removed. It is not possible.
[0004]
However, it is necessary to readjust the carburetor when replacing parts due to an engine failure or the like at an engine manufacturer or a portable work machine dealer. In such a case, even if the structure is such that it cannot be removed by a general driver, the cap can be easily removed at the dealer, and after the carburetor is readjusted below the exhaust gas regulation value, the cap is removed. It is necessary to press-fit again and deliver it so that the driver cannot intentionally remove the cap.
[0005]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to provide a special extraction tool that can easily remove an operation restriction cap at an engine manufacturer or a store.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the configuration of the present invention is such that the fuel adjustment valve is screwed to the carburetor body so as to reduce the passage area as the tip needle portion projects into the fuel passage of the carburetor body. The axial ridge formed on the outer peripheral surface of the cap that is accommodated in the cylindrical portion having a diameter larger than that of the head of the vaporizer body and that is fitted with the head on the inside of the cylindrical portion. A fuel regulating valve that is engaged with a groove wider than the ridge on the peripheral surface and is closed by a sealing plate fixed to the carburetor body, except for the vicinity of one side wall that regulates the maximum amount of fuel in the groove. In the operation limiting device, the step of bringing the protrusion into contact with the one side wall of the groove when screwing the left screw shaft member of the extraction tool while cutting the screw groove into the center circular hole of the bottom wall of the cap; The tip of the extraction tool by screwing the extraction tool A step of abutting the head of the fuel adjusting valve, characterized in that comprising the step of retracting outward the further threadedly to the cap of the extraction tool from the cylindrical portion.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
To remove the cap, engage the extraction tool with the cap hole, and rotate the extraction tool counterclockwise (counterclockwise). The adjusting valve is rotated counterclockwise, and the cap protrusion hits the side wall of the groove of the protruding wall portion of the carburetor body, and cannot be rotated any further. This rotational position is a position where the cap is inserted through the opening of the sealing plate and the selection is fitted to the head of the fuel adjustment valve.
[0008]
When the extraction tool is further rotated counterclockwise, the screw shaft member is inserted into the circular hole while cutting the screw into the circular hole of the cap. When the tip of the screw shaft member hits the head of the fuel adjustment valve, the screw shaft member can no longer move forward, but as the screw shaft member further rotates counterclockwise, only the cap is moved backward or outward by left-handed screw action. The cap can be removed because it moves out of the head of the fuel adjustment valve head.
[0009]
【Example】
FIG. 1 is a left side sectional view showing an operation limiting device for a fuel regulating valve in a membrane type carburetor according to the present invention, and FIG. 2 is a front view thereof. As shown in FIG. 1, the carburetor main body 20 has an intake passage 21 extending in the center portion in a direction perpendicular to the paper surface, a fuel chamber 24 formed in the lower end wall, and a through hole connecting the fuel chamber 24 and the intake passage 21. A fuel nozzle 40 is attached to the fuel tank 22. The fuel nozzle 40 is provided with an annular groove 43 and a radial passage 42 on the peripheral wall of the cup-shaped main body, and a valve body 41 made of a known disk is disposed at the upper end of the main body, and is locked to the upper end of the main body. The valve element 41 is configured so as not to be pulled out upward by the retaining ring 40a provided with the plurality of leg pieces.
[0010]
The fuel adjustment valve 2 is screwed and supported in a screw hole 25 extending in a direction perpendicular to the through hole 22, and the needle portion 3 at the tip protrudes into the passage 23 a and passes from the fuel chamber 24 to the passages 23 and 23 a, the annular groove 43, and the passage 42. After that, the amount of fuel supplied to the intake passage 21 is adjusted. A plurality of positioning pins 26 are integrally formed on the lower wall surface of the vaporizer body 20 and are fitted into positioning holes on a lower wall plate (not shown). The fuel chamber 24 is partitioned by a film sandwiched between the vaporizer body 20 and the lower wall plate. However, such a configuration is well known and is not directly related to the gist of the present invention, so it will not be described further.
[0011]
Preferably, the carburetor body 20 is provided with a protruding wall portion 20a protruding forward (rightward in FIG. 1), and a stepped cylindrical portion 29 formed on the protruding wall portion 20a is connected to the head portion 7 of the fuel adjustment valve 2. An operation limiting cap 10 that limits the adjusting action of the fuel adjusting valve 2 is accommodated.
[0012]
The stepped cylindrical portion 29 includes a cylindrical portion 27 having a diameter larger than that of the screw hole 25, and a rotation retaining ring 9 described later is brought into contact with the stepped portion 28. A flange 6 and a selection 7 b are formed on the head 7 of the fuel adjustment valve 2, and a radial groove 7 a for engaging the extraction tool is formed on the end surface of the head 7 and a V-groove connected to the radial groove 7 a.
[0013]
The cap 10 for operation restriction includes a cylindrical portion 12 for fitting the flange 6 and a selection hole 13 for fitting the selection 7b. A circular hole 15 and a radial groove 16 for inserting the extraction tool in the right end wall. Formed. The inner circumferential wall of the stepped cylindrical portion 29 is formed with a wide axial groove 30 corresponding to a quarter circumference that is partitioned by the side wall 30 a and the side wall 30 b (FIG. 2). The sealing plate 19 is fixed by a method described later made of metal.
[0014]
As shown in FIG. 2, the fuel adjustment valve 2 is composed of a high-speed fuel adjustment valve and a low-speed fuel adjustment valve arranged in parallel with each other, and a stepped cylindrical portion that accommodates a cap 10 attached to each fuel adjustment valve 2. 29 is communicated with each other through the peripheral wall portion. Therefore, the rotation stop ring 9 made of a soft synthetic resin into which both the fuel adjustment valves are screwed is integrated, and is provided with two through holes 9a. The through hole 9a is not threaded. The sealing plate 19 having an approximately oval shape includes two circular openings 19a through which the cap 10 can be inserted, as shown in FIG. A cutout 19b is provided at the edge. The width (circumferential dimension) of the notch 19b is substantially equal to the protrusion 14 of the cap 10, and the sealing plate 19 partially covers the end of the groove 30 provided in the stepped cylindrical portion 29 of the vaporizer body 20. It is summer. In order to prevent the sealing plate 19 from protruding from the protruding wall portion 20a, a recess 31 is formed at the opening edge of the stepped cylindrical portion 29, the outer shape of which is the same as the sealing plate 19, and the depth is substantially equal to the thickness of the sealing plate 19. The Further, a plurality of columns or pins 50 projecting outward are integrally formed on the end wall surface of the projecting wall portion 20 a adjacent to the recess 31. After the sealing plate 19 is fitted into the recess 31, if the end of the pin 50 is crimped, the sealing plate 19 is fixed to the protruding wall portion 20a and cannot be removed.
[0015]
The fuel regulating valve operation limiting device described above operates as follows. Although the sealing plate 19 is fixed in advance to the recess 31 at the opening edge of the stepped cylindrical portion 29 as described above, it may be fixed after the fuel adjustment valve 2 is mounted. First, the extraction tool is engaged with the groove 7a of the head 7 of the fuel adjustment valve 2, the screw portion 4 of the fuel adjustment valve 2 is screwed into the screw hole 25 of the vaporizer body 20, and the large-diameter screw portion 5 is engaged. Is screwed into (cut into) the through hole 9a of the rotation stop ring 9 pressed against the stepped portion 28. In this way, while measuring the fuel amount, the needle portion 3 is protruded into the passage 23a, the area of the gap between the passage 23a and the needle portion 3 is adjusted, and then the fuel adjustment valve 2 is loosened (rotated in the fuel amount increasing direction). The cap 10 is externally fitted to the selection 7b of the head 7 of the fuel regulating valve 2 so that it cannot move.
[0016]
When the cap 10 for limiting operation is pushed into the stepped cylindrical portion 29 from the opening 19 a of the sealing plate 19, the protrusion 14 of the cap 10 is engaged with the groove 30 of the stepped cylindrical portion 29 through the notch 19 b of the sealing plate 19. Match. When the cap 10 is mounted, the fuel adjustment valve 2 is not rotated by the engagement friction between the through hole 9a of the stop ring 9 and the large-diameter screw portion 5 of the fuel adjustment valve 2. Since the cap 10 is inserted into the stepped cylindrical portion 29 and does not protrude outward from the protruding wall portion 20a, it is difficult to remove the cap 10 forcibly.
[0017]
When the driver adjusts the amount of fuel in the carburetor, a driver or other tool is engaged with the groove 16 of the cap 10. In FIG. 2, the protrusion 14 of the cap 10 is engaged with the side wall 30 a of the groove 30 in advance, so that the fuel adjustment valve 2 can be rotated in the clockwise direction (the fuel amount decreasing direction). It cannot be turned counterclockwise (fuel increase direction). As a result, the driver cannot adjust the fuel amount of the carburetor to a value that exceeds the maximum allowable fuel amount set in advance at the time of shipment from the factory, and therefore the operation that violates the exhaust gas regulations of the engine. Can be prevented.
[0018]
As shown in FIG. 1, according to the present invention, when an engine manufacturer or a portable work machine dealer replaces parts due to an engine failure or the like, the operation limiting cap 10 can be easily removed by the extraction tool A. It is what I did. The extraction tool A is a manual operation grip portion 56 provided on a left-handed screw shaft member 55 having a diameter larger than that of the circular hole 15 provided in the cap 10 that is selectively fitted to the fuel adjustment valve 2.
[0019]
When the operation restriction cap 10 is to be removed, when the extraction tool A is engaged with the central circular hole 15 in the bottom wall of the cap 10 and the extraction tool A is rotated counterclockwise (counterclockwise), the screw shaft member 55 is moved. The fuel adjustment valve 2 is rotated counterclockwise together with the cap 10 with the circular hole 15 of the cap 10, and the protrusion 14 of the cap 10 hits the side wall 30 a of the groove 30 of the protruding wall portion 20 a of the carburetor body, Can no longer rotate. This rotational position is a position in which the cap 10 is inserted through the opening 19 a and the notch 19 b of the sealing plate 19 and is seletably fitted to the head 7 of the fuel adjustment valve 2.
[0020]
When the extraction tool A is further rotated counterclockwise, the screw shaft member 55 is inserted into the circular hole 15 while cutting the screw into the circular hole 15 of the cap 10. When the tip of the screw shaft member 55 comes into contact with the head 7 of the fuel adjustment valve 2, the screw shaft member 55 cannot advance any further, but only the cap 10 is left as the screw shaft member 55 further rotates counterclockwise. The cap 10 can be removed because it moves outward (to the right in FIG. 1) by the screw action and escapes from the selection 7b of the head 7 of the fuel regulating valve 2. In this way, after repairing the failure of the carburetor and performing readjustment of the fuel adjustment valve 2 below the emission control value, the cap 10 is pressed again and delivered so that the driver cannot intentionally remove the cap 10. be able to.
[0021]
【The invention's effect】
As described above, according to the present invention , the fuel adjustment valve is screwed to the carburetor body so as to reduce the passage area as the tip needle portion projects into the fuel passage of the carburetor body, and the head of the fuel adjustment valve is vaporized. An axial protrusion formed on the outer peripheral surface of a cap that is accommodated in a cylindrical portion having a diameter larger than the head portion of the vessel body and that is selectively fitted to the head portion is formed by the protrusion on the inner peripheral surface of the cylindrical portion. In an operation limiting device for a fuel regulating valve, which is engaged with a groove wider than the strip, and a portion other than the vicinity of one side wall regulating the maximum fuel amount of the groove is closed by a sealing plate fixed to the carburetor body, A step of bringing the protrusion into contact with the one side wall of the groove when screwing the left screw shaft member of the extraction tool while cutting a screw groove into the center circular hole of the bottom wall of the cap; and screwing the extraction tool The tip of the extraction tool is moved to move the fuel adjustment valve A step of abutting the head, from the withdrawn further threadedly to the cap the tool is made of a step of retracting outward from the cylindrical portion, operating restrictions on the normal driver (user) While the cap can be removed and fuel adjustment exceeding the maximum fuel amount can be prevented, the engine manufacturer and the dealer can easily remove the operation restriction cap for engine maintenance.
[Brief description of the drawings]
FIG. 1 is a left side cross-sectional view showing a removal tool for an operation restriction cap of a fuel regulating valve in a carburetor equipped with an operation restriction device according to the present invention.
FIG. 2 is a front view showing a main part of a vaporizer equipped with the same operation limiting device.
[Explanation of symbols]
A: Extraction tool 2: Fuel adjustment valve 3: Needle part 4: Screw part 5: Large-diameter screw part 6: Flange 7: Head 7a: Groove 7b: Selection 9: Stop ring 9a: Through hole 10: Cap 12 : Cylindrical part 13: Selection hole 14: Projection 15: Circular hole 16: Groove 19: Sealing plate 19a: Opening 19b: Notch 20: Vaporizer body 20a: Projection wall part 21: Intake passage 22: Through hole 24: Fuel chamber 25: Screw hole 26: Positioning pin 27: Large-diameter cylindrical portion 28: Step portion 29: Stepped cylindrical portion 30: Axial groove 31: Recess 55: Left-hand screw shaft member 56: Grip portion for manual operation

Claims (1)

The fuel adjustment valve is screwed to the carburetor body so as to reduce the passage area as the tip needle portion protrudes into the fuel passage of the carburetor body, and the head of the fuel adjustment valve is more than the head of the carburetor body. The axial ridge formed on the outer peripheral surface of the cap that is accommodated in the large-diameter cylindrical portion and that is selet-fitted to the head is a groove that is wider than the ridge on the inner peripheral surface of the cylindrical portion. In a device for restricting the operation of a fuel regulating valve that is engaged and closed by a sealing plate fixed to the carburetor body, except for the portion near one side wall that regulates the maximum amount of fuel in the groove, the center circle of the bottom wall of the cap A step of bringing the protrusion into contact with the one side wall of the groove when the left screw shaft member of the extraction tool is screwed while cutting the screw groove in the hole; and a tip of the extraction tool by screwing the extraction tool Contacting the head of the fuel regulating valve with The withdrawn further characterized by comprising the step of retracting outward the cap from the cylindrical portion and threadedly tool, removal of the operation restricting cap of the fuel adjusting valve method.

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