JPS6321362Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a portable chain saw.

The present invention solves the problems associated with the horizontally opposed two-cylinder engine described in Japanese Utility Model Application Publication No. 54-35495. In other words, the vibrations generated in the direction of reciprocating motion by a horizontally opposed two-cylinder engine can be offset by opposing them on the same straight line, but the horizontal dimension is extremely large compared to that of a conventional single-cylinder engine. As a portable chain saw, it placed a heavy burden on workers. In particular, since the rotating part of the engine is located at the center of two cylinders, one cylinder is located at the front of the conventional chain saw, and the saw chain guide plate on which the saw chain is rotated has to be lengthened. In addition, when this type of opposed two-cylinder engine is used in a vertically opposed manner, there is no need to lengthen the saw chain guide plate, but the operator can use both hands to hold the front handle and rear handle provided in the longitudinal direction of the chain saw body. In order to carry out sawing work by holding the cylinder, the cylinder located at the top faces the worker's face, which not only obstructs the view but also makes it difficult to see the rotating saw chain and the object to be sawed. There were problems with workability, such as the protruding cylinder rebounding in the direction of the face due to the reaction caused by contact with the machine.

The present invention uses a 2-stroke horizontally opposed 2-cylinder simultaneous ignition control engine to solve the problems of conventional portable chain saws, which have many problems associated with horizontally opposed 2-cylinder engines. It is characterized by having the front section facing upward in the longitudinal direction of the aircraft.

The configuration of the present invention will be explained below according to the embodiments shown in the drawings.

This embodiment uses a two-stroke horizontally opposed two-cylinder simultaneous ignition control engine E having a total cylinder exhaust volume similar to that of a single-cylinder engine with the same output. This is because the inertial force of the reciprocating parts of the engine can be offset and the source vibration of the engine can be greatly damped.

As can be seen from Figure 1, the cylinder rows of the engine, which are horizontally opposed to each other, are arranged so that the axis of the cylinder rows is inclined at an angle α with the front section facing upward in the longitudinal direction of the aircraft. The length is reduced. Furthermore, the spark plug P of the front cylinder is tilted further upward with respect to the upwardly tilted cylinder axis to further reduce the length of the fuselage and prevent it from becoming too large. This inclination of the cylinder row axis further helps to form a space at the rear of the upper part and at the front of the lower part of the machine frame 29, and the intake system chamber 41 that accommodates the carburetor 43 etc. is provided in the upper rear space, and the lower front space is can accommodate a muffler M with the exhaust port 42 directed toward the front of the machine so that the source of exhaust noise is farther away from the operator.

That is, the engine E is a two-stroke engine, with the crankcase 1 formed in the center, two cylinders 2 and 3 facing each other horizontally, and a slight offset Q (see Fig. 2) provided along the crankshaft 4. The cylinders 2 and 3 are arranged to enable simultaneous ignition control. An intake port 5 is formed in the upper wall of the crankcase 1 and communicates with a carburetor 43 in the intake system chamber 41 via a reed valve 6, so that the fuel mixture is precompressed and scavenged in the crank chamber. The crankcase 1 is split into two parts in the middle of the crankshaft 4 in a direction perpendicular to the shaft. Ear housing portions 7 and 8 for attaching auxiliary equipment are extended on both outer sides of the crankcase 1. A centrifugal clutch device 9 is attached to the extended shaft portion of the crankshaft 4 in the one-side ear housing portion 7, and a clutch drum 11 integrated with a chain sprocket 10, a safety braking device, etc. are accommodated, and a saw chain guide is installed. A mounting seat 14 for the plate 12, a safety braking lever device 13, etc. are provided. Also, adjacent to this, the oil tank housing part 1
5 is integrated at the rear. Then, lids 16 and 17 are provided on each of them to form an exterior or a container. A flywheel magnet rotor 19 integrally equipped with a blower fan 18 is pivotally attached to the other end extension of the crankshaft 4 in the outer ear housing section 8 on the other side, and an electromotive coil is attached around this flywheel magnet rotor 19. 20, an ignition electronic unit 21, etc., and the outside is covered with a removable lid 22. The lid body 22 is formed with an air intake 23 for blowing air, a recoil starter 24 is integrally attached to the center of the inside, and a transmission pawl 25 provided on the flywheel magnet rotor 19 is connected to the recoil starter 24 .
The crankshaft 4 is made rotatable by engaging and disengaging the starting pawl 26 of the recoil starter 24, thereby making it possible to start the engine E. . These double-sided housing parts 7 and 8 surround both sides of the engine cylinder part, form part of a passage for the blast air, and cool the cylinders 2 and 3. In addition, the engine E section including these binaural housing parts 7 and 8 etc. is connected to the front and rear handles 27.
and a frame body 29 having elastic members 30, 3
1, 32 and 33 in a vibration absorbing manner.
FIG. 3 explains the position of the elastic member, which can effectively prevent vibrations from being transmitted to the handle. That is, an elastic member is provided on the inner surface surrounding the binaural housing portions 7 and 8, and the frame body 29, which is divided into upper and lower halves, faces the elastic member and is inserted and coupled from the upper and lower directions to elastically connect to the engine E section. be combined. A fuel tank 34 is provided at the upper front part of this frame 29, and the intake system chamber 41 is formed at the rear adjacent to this, and a ventilation hole (not shown) is provided around the intake system chamber 41. ing. A rectangular deep dish bottom 35 is formed at the lower front of the frame 29 at a position where the muffler M is accommodated, and a large number of through holes are provided for ventilation and weight reduction.

As described above, the frame body 29 has a rear handle 28 projecting from the rear thereof, and a throttle lever 36, a start/stop switch 37, a throttle safety device 38, etc. are provided on the grip portion of the rear handle 28. The front part of the frame body 29 is in an open state, but is closed with a front lid 39. In addition, the partition plate 40 is designed to prevent the cylinders 2 and 3 from being heated by the muffler M.
It prevents overheating and forms a cooling air passage.

According to the configuration of the present invention, two-cycle horizontally opposed two
By using a cylinder simultaneous ignition control engine, the axis of this cylinder row is directed in the longitudinal direction of the aircraft, and the front part is tilted upward, making it possible to reduce the longitudinal length of the aircraft. The length can be further reduced by tilting the spark plug of the second cylinder upward with respect to the cylinder axis. In addition, since the spark plug at the rear end of the cylinder is slanted along with the cylinder axis, it does not interfere with the operation part of the rear handle, and the length of the saw chain guide plate is considerably longer than that of a conventional two-cylinder model, which is horizontal. Since it can be used by protruding forward for a long time, the length that is shortened in the longitudinal direction of the machine body due to the inclination of the two cylinders can be effectively used to lengthen the exposed part of the saw chain guide plate in front of the saw chain. In addition to improving the ignition capacity of the front cylinder, the ignition plug of the front cylinder is covered with a front cover, which prevents it from being damaged during work. The fuel tank can be cooled, the muffler can have sufficient volume at the bottom, and the exhaust port can be directed forward to prevent workers from being uncomfortable due to exhaust noise and from inhaling exhaust gas that is harmful to their health. Moreover, the muffler can also be cooled while cooling the surroundings of the cylinder with cylinder cooling air, allowing safe exhaust treatment without exposing the muffler.

[Brief explanation of the drawing]

The drawings show one embodiment of the chain saw according to the present invention, and FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken from FIG. 1, and FIG. 3 is an explanatory diagram showing the arrangement of the elastic members. be. E...2-cycle horizontally opposed two-cylinder simultaneous ignition control engine, P...Ignition plug, M...Muffler, 2,
3...Cylinder, 5...Intake port, 6...Reed valve.

Claims (1)

[Scope of utility model registration request] A two-cycle horizontally opposed two-cylinder simultaneous ignition control engine mounted in a frame including front and rear handles, a fuel tank, etc. via a vibration absorbing member, a saw chain rotated by the engine, and a saw chain guide plate that guides the saw chain. The cylinder row axis of the engine is oriented in the longitudinal direction of the aircraft, and the front part is arranged upwardly and the rear part is inclined downwardly, and the spark plug of the front cylinder is inclined upwardly with respect to the axis of the cylinder. and covered by the front cover of the frame, the saw chain guide plate is provided in the longitudinal direction of the fuselage, and a space is formed in the frame at the upper rear of the cylinder row due to the inclination of the axis of the cylinder row. The intake system chamber accommodates intake system members including a carburetor, communicates the carburetor with the crankcase of the engine via a reed valve, and accommodates a muffler in a space formed at the lower front of the cylinder row. A portable chainsaw characterized by its exhaust port facing the front of the machine.