JPH0316558B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention utilizes shaft output generated from a prime mover such as an engine supported on a backpack frame to carry out desired work, such as mowing and pruning by rotating a rotary blade, or felling with a chain saw. The present invention relates to a working machine configured to perform

[Conventional technology]

One of the important factors in determining whether or not this type of work machine is of practical use is whether the transmission of vibrations from the prime mover to the backpack frame is sufficiently damped. If the damping of this vibration is insufficient, the strong vibrations generated by the prime mover rotating at 3,000 to 10,000 revolutions per minute will be transmitted from the backpack frame to the shoulders and back of the worker, and the worker will quickly feel pain from this vibration, resulting in an extremely long life. Unable to withstand hours of continuous work. In a reciprocating internal combustion engine (hereinafter referred to as an engine), which is an example of a prime mover, vertical vibrations occur due to alternating changes in the acceleration of a piston that reciprocates up and down in the cylinder, and a balance weight fixed to the crankshaft. Extremely complex and intense vibrations are generated, which are a combination of vertical and lateral vibrations caused by the rotation of the engine, and lateral vibrations caused by the side thrust during the explosion stroke. In particular, as a power source for backpack-type work equipment, a single-cylinder two-stroke engine, which has the simplest structure and is inexpensive, is generally used. The vibrations generated are intense because the vibrations cannot be sufficiently removed just by being fixed. In this way, the engine can be said to be a source for generating power for work, and at the same time a vibrating body that generates intense vibrations.

[Problem to be solved by the invention]

Various anti-vibration support structures have been proposed for backpack-type work machines to reduce as much as possible the amount of engine vibration propagated to the backpack frame. The upper part of the engine is suspended from the upper part of the backpack frame by a spring, and the lower part of the engine is connected to the lower part of the backpack frame via a universal joint. however,
Although this structure allows the engine to tilt with respect to the backpack frame to some extent, the vibration-proofing effect at the connecting portion between the lower support portion of the engine and the lower portion of the backpack frame remains unsatisfactory. This is because, although there is a universal joint between the lower part of the engine and the backpack frame, there is no elastic material that can provide a vibration damping function.
Furthermore, as shown in Japanese Utility Model Application Publication No. 54-16848, simple coil springs are interposed between the upper part of the engine and the upper part of the backpack frame, and between the lower part of the engine and the lower part of the backpack frame. Although other methods have been proposed, they cannot ensure the support stability of the engine and are completely impractical. The present invention was conceived under the above circumstances, and its purpose is to reduce both horizontal and vertical vibrations of the engine while maintaining a high level of engine support stability. It is an object of the present invention to provide a backpack-type working machine that can effectively damp the vibration.

[Means to solve the problem]

In order to solve the above problems, this invention takes the following technical measures. That is, the present invention provides a backpack-type working machine configured to support an engine on a backpack frame and to transmit power from the engine to a work body via a flexible transmission shaft. In both parts located at the upper and lower sides, an engine support part is provided in which a branch provided integrally with the engine and a branch provided integrally with the backpack frame are vertically opposed to each other. At the section, a shaft extending in a vertical direction passing approximately through the center of gravity of the engine is fixed to one of the opposing branches, and a hole larger than the diameter of the shaft is installed in each other branch. The pair of branch pieces are positioned so that each shaft passes through each hole, and the wire diameter is relatively thick and the winding diameter is relatively thick, so that the displacement of both ends in the direction perpendicular to the axis is The present invention is characterized in that a coil spring formed to have a strong elastic restoring force against each other is interposed between each pair of branch pieces so as to surround each axis.

[Action and effect]

In the present invention, a vibration-proof structure is constructed in which a coil spring is interposed between a support piece that is integrated with the engine and a support piece that is integrated with the backpack frame in two support parts provided at the top and bottom of the engine. Therefore, the vertical vibration of the engine is transmitted to the backpack frame at both the top and bottom of the engine.
effectively reduced. In addition, the above-mentioned coil spring has a strong elastic restoring force at both ends against displacement in the direction perpendicular to the axis, so the transmission of horizontal vibrations from the engine to the backpack frame is effectively alleviated. In addition to the fact that both parts are supported by an equivalent vibration-proof structure, the support stability for the engine backpack frame is also excellent. Moreover, the shafts provided on each branch of the upper and lower support sections are both aligned with the vertical axis passing through the center of gravity of the engine, so that the workpiece connected via the flexible transmission shaft can be swung. Smooth rotation of the engine around the axis during operation is also ensured. Furthermore, the large hole in one branch passes through the shaft in the other branch, so even if a large horizontal load is applied to the engine, the shaft will not come into contact with the inner wall of the hole. This prevents the engine from moving excessively in the horizontal direction with respect to the shoulder frame, which also contributes to supporting stability of the engine. In this manner, the backpack-type working machine of the present invention has a pair of support pieces facing each other, and a shaft provided in one support piece is inserted into a large hole provided in the other support piece.
In addition, a pair of anti-vibration support structures in which coil springs with a predetermined high elasticity are fitted between both support pieces in a shaft-like manner are applied to two locations above and below the engine, and each of the anti-vibration support structures is Since the shaft is aligned with the vertical axis that passes through the center of gravity of the engine, the two anti-vibration support structures have the role of both supporting the engine's load and providing effective anti-vibration. can be done. Although the structure is relatively simple, it can effectively reduce the propagation of vertical and horizontal vibrations generated from the engine to the backpack frame, and the support stability of the engine is not compromised. This has the remarkable effect of ensuring smooth rotation of the engine around the vertical axis when the working body connected via the transmission shaft is swung.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an overall view of the invention applied to a backpack-type power brush cutter. In this brush cutter, an engine 3 serving as a power source is supported on a backpack frame 2 equipped with a shoulder strap 1, and the rotational output from the engine 3 is transmitted to a transmission shaft passed through a flexible transmission pipe 4 or an operating pipe 5. (not shown), it is transmitted to the rotary blade 6 as a working body attached to the tip of the operating tube 5. The backpack frame 2 is formed, for example, by bending and welding a lightweight metal pipe, and includes a horizontal part 2a for supporting the lower part of the engine 3, and a back pad 7 for supporting the upper part of the engine 3. It has a vertical backrest part 2b to which the backrest 2b is attached. The shoulder band 1 is composed of a pair of left and right flexible belts having one end attached to the upper part of the back rest part 2b and the other end attached to the lower part, and a back rest pad 8 is attached to the middle part thereof. The worker carries this backpack frame 2 on his back via the shoulder strap 1,
an operating grip 9 attached to an appropriate portion of the operating tube 5;
9 and swinging the operating tube 5 to perform brush cutting work. Details of the support structure for the backpack frame 2 on the upper part of the engine 3 are shown in FIG. A first branch piece 10 whose base portion is integrally fixed to the engine 3 and a second branch piece 11 whose base portion is integrally fixed to the upper part of the backpack frame 2 are parallel to each other. It extends horizontally. One end of a shaft 12 extending in a vertical direction passing approximately through the center of gravity of the engine 3 is fixed to the first branch 10, and is inserted into a hole 13 made in the second branch 11. In this example, the long bolt 14 under the neck is passed through the hole 13 of the second branch 11 from above, and the tip screw shaft part 16 is passed through the bolt insertion hole 15 made in the first branch 10.
In addition, the first branch 11 is secured to the first branch 11 with two nuts 17 and 18 screwed to a portion located above and a portion located below the first branch 10 of the helical shaft portion 16, respectively.
It is constructed by squeezing the The hole 13 to be drilled in the second branch 11 is made considerably larger than the outer diameter of the shaft 12, that is, the bolt 14, so that the bolt 14 and the hole 13 do not interfere at all under normal conditions. Further, a coil spring 19 is interposed between the first branch piece 10 and the second branch piece 11. As shown in the figure, this coil spring 19 has a relatively large wire diameter and winding diameter, and both ends 19a,
A material having a relatively strong elastic restoring force against displacement in the direction perpendicular to the axis of 19b is used. Also,
The upper end 19a and the lower end 19b are fitted into boss parts 20 and 21 formed on the second branch piece 11 and the first branch piece 10, respectively, and are inserted in the lateral direction with respect to the first branch piece 10 and the second branch piece 11. I try to keep it from moving. In addition, in this engine upper support structure, a collar 23 having a boss portion 22 extending downward is fitted onto the shaft portion of the bolt 14 that penetrates upward from the hole 13 of the second branch 11, and the bolt 14 is fitted with a collar 23 having a boss portion 22 extending downward. The collar 23 is received by the head of the collar 23 to prevent it from slipping out upward, and another coil spring 24 is interposed between the collar 23 and the second branch 11. This coil spring 2
4 plays a role of supporting a part of the weight of the engine 3 on the second support piece 11 while having a buffering effect. As is clear from FIG. 2, the first branch 10 or the bolt 14 can not only move relative to the second branch 11 in the vertical direction, but also move the bolt inside the hole 13 of the second branch 11. 14 can move relative to each other in all horizontal directions. Since rotation of the bolt 14 is also allowed, the first branch 1
The engine 3, which is integral with the engine 1, can rotate around the axis of the bolt 14. Therefore, the first branch 10 or the bolt 14
can move a certain distance relative to the second branch 11 and thus the backpack frame 2 in all three-dimensional directions. Due to this and the fact that the coil spring 19, which is an elastic material, is interposed between the first branch 10 and the second branch 11, vibrations of the engine 3 in all directions are directly transmitted to the second branch 11 or the second branch 11. It is not transmitted to the backpack frame 2,
The anti-vibration effect resulting from this is outstanding. Moreover, since the coil spring 19 has strong elasticity against displacement in the direction perpendicular to the axis at both ends thereof, the first branch 10 and the second branch 11 always try to return to the equilibrium state shown in FIG. The support stability of 2 is maintained at a high level. Details of the support structure for the backpack frame 2 at the bottom of the engine 3 are shown in FIG. This support structure is the engine 3 shown in FIG.
is basically similar to the upper support structure of
2 is provided as a fourth branch 25 that is integral with the backpack frame 2, and a third branch 2 that is integral with the engine 3.
6 is provided with a hole 13 through which the shaft 12 is inserted;
The difference is that there is no spring corresponding to the coil spring 24 described above. Other configurations are the second
Since the configuration is almost the same as that shown in the figure, detailed explanation will be omitted. The function and effect of this part are also the same as the structure shown in FIG. In addition, as shown in FIG. 1, when both the upper and lower sides of the engine are supported by the backpack frame, the axes 12 of both sides are aligned so as to extend in the vertical direction passing through the center of gravity of the engine. The scope of the present invention is not limited to the embodiments shown in the drawings. That is, in the illustrated example, both the upper and lower sides of the engine are supported by the backpack frame, but only the upper part or only the lower part may be supported by the backpack frame. Further, although a bolt is used as the shaft 12 in the illustrated example, it may be constructed by welding a rod to a branch. Furthermore, although the illustrated example is a backpack-type brush cutter, the present invention can be applied to any backpack-type working machine that is supported on a backpack frame and utilizes engine power, such as a pruning machine or a sprayer.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing details of the support structure for the upper part of the engine, and FIG. 3 is a cross-sectional view showing details of the support structure for the lower part of the engine. 2... Back frame, 3... Engine, 10, 26...
...branches integral with the engine (first branch, third branch), 11, 25...branches integral with the backpack frame (second branch, fourth branch), 12...shaft, 13...hole,
19...Coil spring.

Claims (1)

[Scope of Claims] 1. In a backpack-type working machine configured to support an engine on a backpack frame and transmit power from the engine to a work body via a flexible transmission shaft, In both the upper and lower parts, an engine support part is provided in which a branch provided integrally with the engine and a branch provided integrally with the backpack frame are vertically opposed to each other. In the support part, a shaft extending in a vertical direction passing approximately through the center of gravity of the engine is fixed to one of the mutually opposing branches, and a hole larger in diameter than the shaft is provided in each other branch. By positioning each pair of branch pieces so that each shaft passes through each hole, and by forming a relatively thick wire diameter and a relatively thick winding diameter, the direction perpendicular to the axis at both ends is A backpack-type working machine, characterized in that a coil spring formed to have a strong elastic restoring force against displacement is interposed between each pair of support pieces so as to surround each axis.