JPH04121107A - Rotating type lawn mower - Google Patents

Abstract

PURPOSE:To obtain the subject lawn mower capable of readily changing over a method for treating cut lawn without requiring exchange or rearrangement of parts by providing fan blades having a relatively small diameter producing a downward air stream in a specific state. CONSTITUTION:Fan blades 15 are provided so as to be rotatable in the direction opposite to that of cutting blades 12 about the same axial line as that of the cutter blades 12. A dog clutch 23 is subjected to spline engagement with a driving shaft 11 so as to rotate by engagement thereof with a driving bevel gear 19 and rest in releasing thereof.

Description

[Detailed Description of the Invention] Lord! Retired Emperor U-minute! The present invention relates to a rotary lawn mower that cuts lawns with a rotating cutter blade.

The rotary lawn mower has a cutter housing that opens downward, and inside the cutter housing, it rotates approximately horizontally around a nearly vertical axis, and has a cutting blade for mowing the lawn at the front edge in the direction of rotation. A cutter blade is provided. And usually,
The rear part of the cutting blade of the cutter blade has a shape that rises diagonally upward, and the grass clippings cut by the cutting blade are diverted and conveyed into the upper cutter housing by this rising part. It looks like this.

There are various types of rotary lawn mowers depending on how the cut grass is processed. For example, the cut grass inside the cutter housing is passed through a discharge passage provided at the rear of the upper part of the housing to a grass collection bag attached to the rear of the lawn mower. Things to store (rear bag method),
One that discharges grass clippings to the side through a discharge port installed in the side wall of the cutter housing (side discharge method), or one that further shreds the grass clippings and drops it into pieces between the mowed lawns (mulch). There are methods to do this (mulching method), etc.

By the way, if you want to select and adopt the various grass cutting methods mentioned above depending on the type of work and purpose, it is necessary to prepare a dedicated lawn mower for each method, which is economical. It's a heavy burden.

Therefore, a rotary lawn mower that can handle various types of cut grass treatment methods has been proposed. For example, such a rotary lawn mower is shown in U.S. Pat. No. 4,189,903. ing.

This lawn mower is equipped with a normal cutter housing for the rear bag method or side discharge method. When converting this to the mulching method, a second cutter housing for mulching is installed inside the cutter housing along the inner surface of the cutter housing. The cutter housing (liner) is attached to the cutter housing (liner).

The second cutter housing is not provided with a cut grass discharge path or outlet, but instead has a guide that directs the cut grass, which is cut by the cutter blade and flies upward, downward to the center of the housing. A vane is provided, and the cut grass that is guided by the guide vane and falls down the radially inner part of the housing is cut again by the cutting blade of the inner part of the cutter blade and becomes fine, and then the cut grass is cut into fine pieces. It seems to fall between the ground and the grass.

In the conventional lawn mower mentioned above, for example, in order to switch from the rear bag or side discharge method to the mulching method, the cutter blade is removed and the second force/interhousing is inserted into the cutter housing from below. The cutter blade must be fitted and installed, then the cutter blade must be reinstalled, and the second cutter housing must be removed in the reverse order to switch from the mulching method to the bag or side discharge method. Cumbersome work is required when switching the processing method.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a lawn mower that allows easy switching of the grass cutting method without such troublesome parts replacement or reassembly work.

For this purpose, the present invention includes a cutter housing that opens downward, and a cutter housing that rotates approximately horizontally around a substantially vertical axis within the cutter housing, and has a mowing cutter provided at the front edge in the direction of rotation. A rotary lawn mower comprising a cutter blade having a blade and a cutter blade having a tip having a cross-sectional shape that deflects the cut grass cut by the cutting blade upward with respect to the horizontal rotating surface. , a comparative member rotating about the same axis as the cutter blade in a direction opposite to the direction of rotation of the cutter blade to generate a downward air flow between the upper wall of the cutter housing and the rotating surface of the cutter blade. A small-diameter fan blade is provided, and a drive system for rotationally driving the cutter blade and the fan blade is provided with a switching mechanism capable of stopping only the fan blade.

When this lawn mower is used as a mulching lawn mower, both the cutter blade and the fan blade are simultaneously driven to rotate by the drive means with the cutter housing filter bag and side discharge outlet closed.

As the cutter blade rotates, an upward airflow is generated in the cutter housing at its outer periphery caused by the cross-sectional shape of the tip of the cutter blade, and a swirling airflow is generated overall in the direction of rotation of the cutter blade. On the other hand, as the fan blade rotates, a downward airflow is generated inside the outer peripheral portion within the cutter housing, and a swirling airflow is also generated by the fan blade in the direction of rotation thereof. Here, since the cutter blade and the fan blade rotate in opposite directions, the directions of the respective swirling flows caused by them also become opposite to each other. As a result, the two swirling flows cancel each other out, and the horizontal swirling flow within the housing is greatly reduced or eliminated, resulting in a series of vertical convection caused by the upward flow caused by the cutter blade and the downward flow caused by the fan blade. is the main flow inside the housing.

The lawn mower passes through mowing marks while mowing the lawn with the cutting edge at the tip of the cutter blade. The grass cut by the cutting blade rides on the upward flow and rises along the outer periphery of the housing, then descends on the inner side of the housing due to the downward flow, and is blown onto the mowed grass surface. At this time, the finely shredded grass clippings are pushed into the grass grain, and the long pieces that have not been shredded rest on the grass, so they ride the airflow below the cutter blade generated by the convection and return to the cutting edge at the tip of the cutter blade. The material is conveyed to the housing, is shredded by the cutting blade, and ascends within the housing.

When using this lawn mower as a rear bag type or side discharge type lawn mower, open the cut grass discharge port on the cutter housing, install the grass collection bag if necessary, and then turn the switching mechanism to stop the fan blade. to rotate only the cutter blade.

In this case, since the fan blade is stationary, the only air flow within the cutter housing is the upward flow and swirling flow generated by the cutter blade. This flow is exactly the same as that of conventional lawn mowers that are exclusively used for bag-type or side-discharge types. The grass clippings move along the side wall of the housing and are stored in the grass collection bag or discharged to the side through the outlet.

As described above, according to the present invention, not only can one rotary lawn mower be made compatible with various grass cutting methods, but also the method can be changed by operating the switching mechanism to change the cutter blade and fan blade. This is done by changing the driving mode, and there is no need for any troublesome work such as replacing or rearranging parts when switching.

! Twisting The present invention will now be described with reference to an illustrated embodiment. 1st
3 to 3 are perspective views of the rotary lawn mower 1 according to the present invention, in which FIG. 1 shows the rotary lawn mower 1 during mulching work, FIG. 2 shows the lawnmower when storing a lawn mower, and FIG. 3 shows the rotary lawn mower 1 during side discharge work. This lawn mower 1 consists of a lawn mower 3 supported by running wheels 2, an engine 4 mounted on the lawn mower 3, and a handle 5 extending rearward from the lawn mower 3. By operating the latch lever 6, the running wheels 2 are driven by the engine 4, and the lawn mower l
runs. The handle 5 is also provided with levers for controlling the engine 4.

As shown schematically in FIGS. 9 and 10, the lawn mowing section 3 is provided with a cut grass discharge lower for rear bag storage work and a cut grass discharge port 8 for side discharge work. During mulching work (FIG. 1), both of these discharge lowers 8 are closed. When storing the rear bag (
In FIG. 2), a grass collection bag 9 is connected to the discharge lower and supported by the handle 5, and the discharge port 8 is kept closed.

Therefore, the cut grass in the lawn mower 3 is stored in the grass collecting bag 9 via the discharge lower. During side discharge work (Fig. 3), the discharge lower is closed and the discharge port 8 is opened. Therefore, the cut grass in the mowing section 3 is discharged to the side through the discharge port 8.

FIG. 4 is a longitudinal sectional view of the lawn mower 3. The lawn mower 3 has an upper wall 10. and a side wall IO8, and includes a bottomed cylindrical cutter housing IO that is open toward the bottom, and a drive shaft 11 connected to the crankshaft of the engine 4 passes through the central opening of the upper wall 101 from above. It extends vertically into the cutter housing 10 .

A cutter blade 12 is fixed to the lower end of this drive shaft 11 via a bolt 13 and extends in the diametrical direction of the cutter housing 10. Both outer portions 12 of the cutter blade 12. , 12. is the side wall 1 of the cutter housing 10
0. located at almost the same height as the bottom edge of the
Close to 0g. As shown in FIG. 5, the outer portion 12+ is provided with a cutting edge 14 along the front edge in the direction of rotation, and the rear edge is provided with a rising portion 12g that rises diagonally upward.
It becomes. Therefore, the outer portion 12. has a cross-sectional shape as shown in FIG. 6, and has a rising portion 12. when rotated. Since an upward air current is generated by the cutting blade 14, the grass cut by the cutting blade 14 is caused by this upward air current and the rising portion 12. The cutter blade 12 is guided directly by the cutter blade 12 and deflected upward with respect to the rotational surface of the cutter blade 12 .

Also within the cutter housing 10 is a top wall 10 . A fan blade 15 is provided between the cutter blade 12 and the cutter blade 12 . The fan blade 15 is fixed to a cylindrical outer drive shaft 17 that is rotatably mounted on the outside of the drive shaft 11 concentrically and rotatably via a ball bearing 16, and parallel to the rotational surface of the cutter blade 12. Rotate in the horizontal plane. A driven bevel gear 18 is fixed to the upper end of the outer drive shaft 17 so as to rotate together with the driven bevel gear 18. Above the driven bevel gear 18, a driving bevel gear 19 is rotatably connected to the drive shaft 11 via, for example, a needle bearing 20. is installed on. An intermediate bevel gear 21 meshes with the driven bevel gear 18 and the driving bevel gear 19. The intermediate bevel gear 21 is rotatably supported by a gear case (not shown) connected to the engine 4 via a bearing 22.

A dog clutch (switching mechanism) 23 is provided adjacent to the upper surface of the drive bevel gear 19. The dog clutch 23 is spline-fitted to the drive shaft 11, and slides in the axial direction to engage with or disengage from the drive bevel gear 19. In Figure 4, dog clutch 2 is on the left.
3 shows the state when the dog clutch 23 is engaged with the drive bevel gear 19, and the right side shows the state when the dog clutch 23 is disengaged from the drive bevel gear 19. The dog clutch 23 is the driving bevel gear 1
9, the rotation of the drive shaft 11 is controlled by the dog clutch 23.
The driving bevel gear 19 rotates integrally with the drive shaft 11. This rotation is caused by the intermediate bevel gear 21, the driven bevel gear 18, and the outer drive shaft 1.
7 to the fan blade 15, and the fan blade 15 rotates together with the cutter blade 12. However, as can be seen from the above gear combination, the fan blade 15 rotates in the opposite direction to the direction of rotation of the cutter blade 12. When the dog clutch 23 disengages from the drive bevel gear 19, the drive connection between the drive shaft 11 and the drive bevel gear 19 is cut off, so the fan blade 15 remains stationary and only the cutter blade 12 is rotationally driven by the drive shaft 11. Ru.

The fan blade 15 is provided with vanes 151,
The fan blade 15 is connected to the cutter blade 12 as described above.
When rotating in the opposite direction, this blade 15. A downward airflow is generated. Note that since the diameter of the fan blade 15 is made smaller than the diameter of the cutter blade 12, the cutter blade 12 is provided on the outer periphery inside the cutter housing 10.
Outer portion 12. An upward air current is generated due to this, and a downward air current is generated inwardly due to the blades 151 of the fan blade 15.

FIG. 7 shows the state of the lawn mower 3 during mulching work. When the lawn mower 1 is used as a mulching lawn mower, the cut grass discharge lower, 8 (
9 and 10) with a suitable lid member, and the dog clutch 23 is set to the engagement position with the drive bevel gear 19. When the drive shaft 11 is driven by the engine 4 in this state, both the cutter blade 12 and the fan blade 15 rotate. The lawn mower 1 has an outer portion 12. of the canter blade 12. Since the cutter housing 10 moves forward while mowing the lawn 24 with the cutter U14, the lower part of the cutter housing 10 is the part where the lawn has been mowed (mowing marks).
It becomes 25.

As mentioned above, inside the cutter housing 10, there is an upward airflow a caused by the cutter blade 12 and a downward airflow a caused by the fan blade 15! However, the cutter blade 12
As the fan blades 15 rotate, horizontal swirling air currents tend to occur in the corresponding rotational directions. However, since the cutter blade 12 and the fan blade 15 rotate in opposite directions, the directions of the swirling airflows caused by them also become opposite to each other, and the swirling airflows cancel each other out, causing the horizontal direction inside the cutter housing 10 to be The swirling airflow is greatly reduced or eliminated. Therefore, the upward airflow a at the outer circumferential portion and the downward airflow a2 at the inner portion become the main airflow inside the cutter housing 10, and along with this, the airflow flows downward from the inside to the outside in the radial direction of the cutter blade 12, and then to the outside. Part 12. An air flow a is generated which enters the cutter housing 10 through the cutter housing 10.

The cut grass 26 cut by the cutting blade 14 rides on the upward air current a and rises along the side wall 10t of the cutter housing 10, and then reaches the upper wall 10. It then moves down the inner part of the cutter housing 10 by the downdraft a2 and is blown onto the grass surface of the mowing marks 25. At this time, the finely shredded grass 26 is the grass 24 of the mowing trace 25.
It is pushed between the grass and becomes mulch, but long pieces that are not shredded are grass 24. Since it rides on top of the blade, it is carried again by the downward airflow a3 to the cutting blade 14 of the outer portion 121, and is cut by the cutting blade, following the same path as above.

By repeating such actions, all the grass clippings are shredded and dropped between the grass in the mowing marks 25 as mulch.

FIG. 8 shows the state of the lawn mower 3 during rear bag storage work and side discharge work. When the rear bag storage method is used, as shown in FIG. 9, the grass collection bag 9 is connected to the cut grass discharge lower of the cutter housing 10, and the discharge port 8 is closed with a lid 8I. As shown in FIG. 10, the discharge lower is connected to the lid member 7. The discharge port 8 is closed and the discharge port 8 is opened. In either case, the dog clutch 23 is set to the disengaged state.

In this state, the rotation of the drive shaft 11 is not transmitted to the fan blades 15, so the fan blades 15 stand still and only the canter blades 12 rotate. Therefore, due to the rotation of the cutter blade 12, an almost horizontal swirling air current is generated in the housing 10, which circulates along the side wall 10□ in the direction of rotation of the cutter blade 12, as well as an upward air flow similar to that described above. 26 rides on this swirling air flow and moves the side wall 10
Turn along □.

When storing the rear bag, the grass passes through the discharge lower into the grass collection bag 9 and is stored there, and during side discharge work, it is discharged to the side through the discharge port 8.

In this way, the rotary lawn mower 1 of this embodiment can be used with various grass cutting methods with just one unit, and furthermore,
When switching the method, it is sufficient to open and close the cutter housing 10's grass cut discharge lower 8 as appropriate, and then simply set the switching mechanism, that is, the dog clutch 23, to either the engaged or disengaged state, and there is no need to replace parts when switching. , does not require any troublesome work such as rearrangement.

As described above, the present invention has a cutter housing that opens downward, rotates approximately horizontally around an approximately vertical axis within the cutter housing, and has a mowing blade on the front edge in the direction of rotation. A rotary lawn mower comprising a cutter blade having a cutting blade and a cutter blade having a tip having a cross-sectional shape that deflects the cut grass cut by the cutting blade upward with respect to the horizontal rotating surface. between the upper wall of the cutter housing and the rotating surface of the cutter blade;
A drive for rotationally driving the cutter blade and the fan blade, wherein a relatively small diameter fan blade is provided around the same axis as the cutter blade and rotates in a direction opposite to the direction of rotation of the cutter blade to generate a downward airflow. Since the system is provided with a switching mechanism that can stop only the fan blade, one rotary lawn mower can be adapted to various grass cutting methods. Furthermore, the switching mechanism changes the driving mode of the cutter blade and fan blade to I! which rotationally drives both the cutter blade and the fan blade. Since the keyaki and fan blades are stopped and only the cutter blade is driven to rotate, the changeover does not require any troublesome work such as replacing or rearranging parts.

[Brief explanation of the drawing]

1 to 3 are overall perspective views showing a rotary lawn mower according to an embodiment of the present invention during mulching work, rear bag storage work, and side discharge work, respectively, and FIG. 4 shows the same lawn mower Fig. 5 is a perspective view of the cutter blade, Fig. 6 is a vertical cross-sectional view of the mowing section of Fig.
7 is a cross-sectional view showing the state of the lawn mower during mulching work, Figure 8 is a cross-sectional view showing the state of the lawn mower during field bag storage work and side discharge work, and Figure 9 is a cross-sectional view taken along line l. FIG. 10 is a schematic diagram for explaining the state of the cut grass outlet during the side discharge operation. FIG. 10 is a schematic diagram for explaining the state of the cut grass outlet during the side discharge operation. 1... Lawn mower, 2... Running wheel, 3... Lawn mowing section, 4
... Engine, 5 ... Handle, 6 ... Latch lever for running 7.8 ... Discharge port, 9 ... Grass collection bag, 10
...Cutter housing, 11...Drive shaft, 12...
・Cutter blade, 13... Bolt, 14... Cutting blade, 15... Fan blade, 16... Ball bearing, 17
... Outer drive shaft, 18... Driven bevel gear, 19...
Drive bevel gear, 20... Needle bearing, 21... Intermediate bevel gear, 22... Bearing, 23... Dog clutch,
24...grass, 25...mowing marks, 26...mowed grass.

Claims (1)

[Claims] A cutter housing that opens downward, rotates approximately horizontally around an approximately vertical axis within the cutter housing, has a cutting blade for mowing the lawn at the front edge in the direction of rotation, and uses the cutting blade to cut the tip. In the rotary lawn mower, the rotary lawn mower includes a cutter blade formed in a cross-sectional shape that deflects the cut grass upward with respect to the horizontal rotating surface. A relatively small-diameter fan blade that rotates around the same axis as the cutter blade in a direction opposite to the direction of rotation of the cutter blade to generate a downward airflow is provided between the cutter blade and the rotating surface, A rotary lawn mower characterized in that a drive system for rotationally driving fan blades is provided with a switching mechanism capable of stopping only the fan blades.