JPS6325295Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a muffler mounting structure for chainsaws, brush cutters, etc., and more specifically, to a mounting structure for a combination type muffler consisting of a base muffler, a cover muffler, etc.

In Fig. 1, which shows a muffler for a conventional engine such as a chain saw, the structure in which a combination muffler consisting of a base muffler 2, a cover muffler 3, and a shielding plate 4 is attached to the exhaust port of a cylinder is as shown in Fig. 1. Two bolts 5, which are held in contact with the cover muffler 3 via the bolt seats 3b, are passed through the muffler housing 1 and screwed into the exhaust port 6. At this time, the engaging portion 2a of the base muffler 2 is engaged and press-contacted with the engaged portion 3a of the cover muffler 3 via the shielding plate 4. 7 is a reinforcing pipe tube.

Therefore, rotate the engine and open the muffler housing 1.
When exposed to high temperatures for a long time, the muffler housing 1 expands more than the bolts 5, and the portion of the cover muffler 3 that is held in contact with the bolt seats 3b tightened by the bolts 5 is suppressed from expanding. .
Then, when the rotation of the engine is stopped and the temperature of the muffler housing 1 returns to normal temperature, the muffler housing 1 should return to its original shape, but the cover muffler 3
is apparently compressed by a dimension corresponding to the dimension in which the expansion was previously suppressed, and the bolt 5 becomes loosened. Therefore, the muffler flops, gas leaks, and the engine gets dirty. This, in turn, has the disadvantage of damaging the internal threads of the cylinder and necessitating replacement of the cylinder. Therefore, in order to solve this problem, in another conventional technique, as shown in Fig. 2, both ends of an elongated thick plate are bent vertically to form a U-shape.
Of this bent part, the cover muffler 13 mounting side 1
5a and 15'a are threaded, and the base muffler 12
Two muffler mounting members 15, 15' with holes were prepared on the mounting sides 15b, 15'b. Note that the bent portions 15a and 15a at both ends of the mounting members 15 and 15', respectively,
15b, and the distance between the outer surfaces of 15'a and 15'b is the distance between the inner surfaces of the muffler housing 11 that brings the engaging portion 12a of the base muffler 12 into engagement and pressure contact with the engaged portion 13a of the cover muffler 13. It corresponds to

Therefore, the muffler mounting members 15, 15' are screwed to the exhaust port 6 through the base muffler 12 with bolts 16, and the screws 17 are used to connect the engaged portion 13a of the cover muffler 13 to the engaging portion 12a of the base muffler 12.
The cover muffler 13 was screwed on by engaging and press-fitting the cover muffler 13. However, since the threaded part of the screw 17 is exposed inside the muffler, carbon tends to adhere to it, and when disassembling the muffler to remove carbon, the threaded part inside the muffler may have carbon attached to it and the screws may not be removed. It had the disadvantage of being difficult.

The present invention was devised to solve the above-mentioned drawbacks, and its purpose is to provide a muffler mounting structure in which the muffler mounting bolts do not loosen and the threaded portions of the bolts are not exposed inside the muffler.

In order to achieve the above object, the present invention brings the engaging part of the base muffler into engagement and pressure contact with the engaged part of the cover muffler to form a muffler housing, and attaches the muffler housing to the exhaust port part. for,
The present invention is characterized by a muffler mounting structure including a bolt that has one end screwed onto the exhaust port portion, passes through the muffler casing, and has the other end screwed onto the threaded member.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, the same reference numerals as in FIG. 1 represent the same parts, and detailed explanations will be omitted.

As shown in FIGS. 3 and 4, the bolt 25 is
Between the inner surfaces of the muffler casing formed by the base muffler 2 and cover muffler 3, the positional relationship is such that the engaging part 2a of the base muffler 2 is brought into engagement and pressure contact with the engaged part 3a of the cover muffler 3 via the shielding plate 4. A threaded portion 25b having a rod 25a with a length equal to the interval and having a step at one end and screwed into the exhaust port portion 6.
The other end is stepped and has a threaded portion 25c screwed onto the nut 26. Furthermore, rod 2
When the seat plate 28 is used, the length of the seat plate 5a is reduced by the thickness thereof.

Therefore, in order to assemble the muffler and attach it to the exhaust port 6, first insert the bolt 25 into the hole drilled in the base muffler 2 through the seat plate 28, and screw the threaded portion 25b onto the exhaust port 6. By doing so, the base muffler 2 is attached to the exhaust port 6. Next, the engaged portion 3a of the cover muffler 3 is engaged with the engaging portion 2a of the base muffler 2 via the shielding plate 4,
Engage the cover muffler 3 with the base muffler 2. At this time, the threaded portion 25c of the bolt 25 projects outward from the hole drilled in the cover muffler 3. The nut 26 is screwed onto this threaded portion 25c to complete the installation of the muffler to the exhaust port portion 6.

In this case, the total length of the rod 25a of the bolt 25 and the thickness of the seat plate 28 regulates the engagement portion 2a of the base muffler 2 to be brought into engagement and pressure contact with the engaged portion 3a of the cover muffler 3. Therefore, the cover muffler 3 will not be lifted off the base muffler 2, and the various parts of the muffler mounting structure will not become loose. Also, the threaded portions 25b and 25c of the bolt 25
Since it is located outside the muffler housing 1, carbon will not adhere to it, so disassembling the muffler is easy.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that changes can be made at any time without departing from the scope of the invention, such as the fact that the mounting threads of the cover muffler may be either male or female.

As is clear from the above explanation, according to the present invention,
In the combined muffler, the mounting structure does not loosen even after long-term use, and the muffler can be easily disassembled, which is an excellent practical effect.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an example of a conventional muffler mounting structure, Fig. 2 is a sectional view of another conventional example, Fig. 3 is a sectional view of an embodiment of the present invention, and Fig. 4 is a sectional view of an example of the conventional muffler mounting structure. −
FIG. 1, 11...Muffler housing, 2, 12...Base muffler, 2a, 12a...Engaging portion, 3, 13
...Cover muffler, 3a, 13a...Engaged part, 5, 25...Bolt, 6...Exhaust port part, 25
a...rod, 25b, 25c...screw part, 26...
Natsuto.

Claims (1)

[Scope of utility model registration request] a muffler housing in which an engaging part of a base muffler is brought into engagement and pressure contact with an engaged part of a cover muffler;
A chain saw comprising: a bolt that has one end screwed onto an exhaust port of a cylinder to pass through the muffler housing, and the other end screwed onto a threaded member to hold the muffler housing. etc. muffler mounting structure.