JPH026B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a power lawn mower equipped with an engine having a vertical crankshaft.

2. Description of the Related Art Power lawn mowers are in practical use, which are equipped with an engine and use the engine as a power source to rotate a cutter blade in a horizontal plane, and are driven by the power or by hand.

As for the engine of the above-mentioned power lawn mower, when the crankshaft is placed horizontally, the direction of rotation is different between the cutter blade and the cutter blade, which rotates in the horizontal plane. Requires a conversion transmission mechanism, complicating the structure,
This is undesirable because it increases the number of parts and increases the size.

Therefore, if a vertical engine with a vertical crankshaft is used, since the crankshaft is vertical, the cutter blade can be directly connected to the lower end of the crankshaft, and there is no need for a direction change or transmission mechanism. The above-mentioned inconvenience can be solved.

By the way, conventional lawn mowers of this type are equipped with wheels.
Since the engine is rigidly mounted and connected to the cutter blade housing, which is equipped with a grass storage bag and has an operating handle, engine vibrations are transmitted to the handle via the housing, resulting in an unfavorable operating feel. In particular, in vertical engines, the cylinders are installed horizontally, facing front and rear or left and right, and the rotation of the crankshaft in the horizontal plane generates primary inertia of the engine in the front and rear or left and right directions, which is transmitted as vibration through the housing. This was transmitted to the steering wheel, impairing the sense of operation, and improvements were desired.

The present invention has been made to improve the above-mentioned problems, and its purpose is to isolate engine vibrations from the housing as much as possible, suppress transmission of vibrations to the housing and the handle as much as possible, Excellent operating feel,
Further, it is an object of the present invention to provide a power lawn mower which is advantageous in terms of noise prevention and which can accomplish the above with a simple structure.

In order to achieve the above object, the present invention connects a cutter blade rotating in a horizontal plane directly to the lower end of a vertical engine in which the cylinder is horizontal and the crankshaft is vertical. , the engine is mounted and supported on the housing via an elastic body disposed outward in the circumferential direction of the crankshaft, with the engine facing onto the housing that includes a handle, etc., and the housing and engine are aligned with respect to the crankshaft axis. The gist is that the shafts are connected to each other so as to be relatively rotatable around the shafts, which are disposed orthogonally to each other.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a side view of a power lawn mower 1, where 2 indicates a housing which also serves as the machine body, and the four corners of this housing are equipped with wheels 3, which can be driven by engine power or manually operated. It may be configured with wheels so that it can be moved by operation. A handle 4 extending rearward and upward is provided on the rear of the housing 2, and in the embodiment, a grass storage bag 5 is disposed on one side of the handle 4, and the bag has an upper rear end attached to the upper part of one side of the handle. The front end is connected to a cut grass discharge portion 201 that projects above the peripheral portion of the housing 2.

A power unit 6 is disposed on the housing 2, the outside of which is covered with a cover 601 in the figure, and a fuel tank 602 is provided at the rear of the power unit.

FIG. 2 is a longitudinal cross-sectional view showing the main parts of the engine 7 and the housing 2, which form the main body of the power unit 6. 7
01 is arranged horizontally, and a crankcase 702 is connected to the base of the cylinder part 701 so as to face downward.The figure shows a cantilevered crankshaft type, so the upper end of the crankcase 702 is a cover with a diagonal joint. 703, crankcase 70
2 is a hanging extended case portion 704 that protrudes downward.
A large-diameter mounting flange portion 705 is formed at the lower end of the case portion 704. The case portion 704 faces above the central portion of the housing 2, a through hole 202 is provided vertically in the central portion of the housing 2, and a skirt portion 204 is provided in the peripheral portion of the upper wall 203.
is suspended, and inside this there is a double partition wall 205,
206 is provided, and a guide duct 207 is provided to discharge the cut grass to the discharge section 201.

As is known, a piston (not shown) is fitted in the cylinder portion 701 so as to be slidable in the horizontal direction.
Crankshaft 706 is crankcase 70
2. The crankshaft 706 is housed vertically in the case 704, and the crankshaft 706 is of a cantilever type and is connected to the piston via a connecting rod 708 through a pin portion provided near the outer end in the radial direction of the upper web 707. A crankshaft shaft portion 709 that is connected and vertically suspended from the web 707 is supported by bearings 710, 710 that are vertically spaced apart from each other.

The lower end 711 of the shaft 709 of the crankshaft 706 is suspended below the flange 705 of the case 705, and the lower end is inserted into the lower part of the housing 2 through a joint shaft 712 that extends vertically through the vertical through hole 202 of the housing. The cutter blade 8 is connected to the holder 801 of the cutter blade 8 housed in the holder 801, so that the blade 8 is rotated by the engine power in a horizontal plane.
Lawn mowing work will be carried out.

In the above, an elastic body, specifically a mount rubber 9, is interposed between the center part of the upper wall 203 of the housing 2 and the flange part 705, and the engine faces onto the upper wall 203 of the housing via the rubber 9. 7
The flange portion 705 forming the mounting base is connected to the flange portion 705. The rubber 9 is, for example, the flange portion 7 of the engine 7.
The upper end can be attached to the lower surface near the periphery of 05 by baking or the like, and the seat plate provided at the lower end can be attached to the upper wall of the housing 2, or vice versa. are provided and coupled to the flange portion 705 and the housing upper wall 203, respectively, and the engine 7 is mounted and supported on the housing 2 via the elastic body 9. A plurality of the above rubbers 9 may be provided radially around the crankshaft shaft 709, or
It is also possible to use a concentric ring shape with 9 at the center.

At symmetrical positions on the circumference of the flange portion 705, mounting bracket portions 713 are provided to hang down and protrude, while on the corresponding portions of the upper wall 203 of the housing 2, there are bracket portions 205 that wrap inwardly and outwardly with the bracket portions 713. The pin 10 is passed between the bracket parts 713 and 205, and both are pivotally supported. The pin 10 is provided horizontally so as to be perpendicular to the axis of the crankshaft shaft portion 709.

Next, its effects will be explained in detail.

The engine 7 configured as shown in FIG. 2 is pivotally supported in the housing 2 by a pin 10 provided in a direction perpendicular to the crankshaft axis.

Therefore, by generating the primary inertia force generated from the engine so as to act around the pin 10, and setting the pin 10 to be at or near the instantaneous center of the engine 7, vibration isolation can be effectively achieved. It can be demonstrated.

The rubber 9 is intended to prevent the engine 7 from vibrating more than necessary, and must be prevented from causing resonance phenomena as a vibration system with respect to the vibration frequency generated by the engine 7.

The position B of pin 10 is the center of gravity G of the engine system, the moment of inertia I _G around the center of gravity, the mass M of the engine system,
It can be determined from the relationship with the distance A from the center of gravity G to the conrod 708, which is the source of vibration, as follows: B=I _G /M×A.

As detailed above, according to the present invention, in a power lawn mower equipped with a vertical engine, transmission of engine vibration to the housing can be prevented as much as possible, and this type of lawn mower has excellent operational feel and low noise. The above can be contemplated with a simple structure in which the engine and the housing are connected by an elastic body, and the crankshaft is connected to a pin orthogonal to the crankshaft.

[Brief explanation of drawings]

Figure 1 is a side view showing an example of a lawnmower, Figure 2 is a longitudinal cross-sectional view of the main parts of the engine and housing, and Figure 3 is a side view showing an example of a lawn mower.
The figure is a perspective view of a pin joint. In the drawings, 1 is a lawn mower, 2 is a housing, 7 is an engine, 706 is a crankshaft, 8 is a cutter blade, 9 is an elastic body, and 10 is a support shaft.

Claims (1)

[Scope of Claims] 1 a. A cutter blade that is housed in a housing and rotates in a horizontal plane is rotationally driven by a substantially vertical crankshaft of a vertical engine disposed on the housing; b. A cutter blade that is disposed on the housing and on the housing; The housing and the engine are connected to each other via an elastic body disposed outwardly around the crankshaft, c. The housing and the engine are connected to each other by a support shaft provided in a direction orthogonal to the substantially vertical crankshaft. A power lawn mower having the above configuration, which is coupled to be relatively rotatable around the support shaft.