JPH0411812A - Grass-cutter - Google Patents

Abstract

PURPOSE:To enable sure engagement and disengagement of a clutch by positioning a clutch-operation member at a side opposite to an engine cylinder with respect to a crank shaft. CONSTITUTION:A crank shaft of an engine 5 is placed in vertical direction and a cylinder 8 is placed in horizontal direction. An arm member 37 of an operation member of the clutch device, a hooking piece 45, a brake spring 47, a clutch spring 48, etc., are positioned in front of the engine above a cutter housing 3, i.e., at a side opposite to the cylinder 8 with respect to the crank shaft. The swinging angle of the arm member can be increased by this structure.

Description

[Detailed Description of the Invention] Skin! TECHNICAL FIELD The present invention relates to a lawn mower in which a cutting section consisting of a cutter blade or the like is housed in a housing, and an engine for driving the cutting section is mounted on the upper part of the housing.

Such a lawn mower is shown, for example, in U.S. Pat. No. 3,696,595. This lawnmower includes a cutter blade directly connected to the output shaft of an engine, and a paddle wheel rotatably supported by the output shaft and drivingly connected to the output shaft via a speed reduction device consisting of a belt and a pulley. ing. In this lawn mower, the cutter blade and paddle wheel are always drivingly connected to the engine output shaft.

Therefore, when the cutter blade and paddle are temporarily stopped during work, the engine must be stopped each time, and when the rotation of the blade and paddle is restarted, the engine must be started each time, which improves work efficiency. Good (no)

U.S. Pat. No. 2,960,810 discloses a clutch mechanism for disconnecting power transmission from a motor shaft to a cutter blade in a lawn mower. In this clutch mechanism, one ■-shaped pulley is formed by a flange fixed to the motor shaft and a flange that is coaxially fixed to the cutter blade and rotatably attached to the motor shaft and faces the fixed flange. , a V-belt is passed between this pulley and another movable pulley,
By displacing the displaceable pulley and tensioning the V-belt between both pulleys, power is transmitted from the flange fixed to the motor shaft via the V-belt to the rotatable flange and hence the cutter blade, and the V-belt Power transmission is interrupted by relaxing the . For this purpose, an operating lever is provided for displacing the displaceable pulley to operate the clutch, and the operating lever is disposed at the rear side of the aircraft by passing through the side wall of the hood covering the engine. ing.

Since the lawn mower of U.S. Pat. No. 2,960,810 is operated by an operator seated on the lawn mower, the operating lever is provided at the rear of the machine body near the seat. However, this position is not necessarily suitable for all types of lawn mowers; for example, in walk-behind lawn mowers, the front end of the mechanical action handle that extends rearward is attached to this position, so it is difficult to operate the operating lever. It is difficult to provide the lever at this position without interfering with other members and with sufficient space for movement of the lever.

The present invention has been made in view of these circumstances.
In the present invention, in a grass lawn mower in which a cutting part for cutting grass is housed in a housing, and an engine for driving the cutting part is mounted on the upper part of the housing, the crankshaft of the engine is moved vertically and the cylinder is moved horizontally. Place it towards the
A power transmission device for transmitting engine power from the crankshaft to the mowing section and a clutch device for disconnecting the power transmission are provided in the housing, and the operation member of the clutch device is inserted through the upper wall of the housing. and on the opposite side of the cylinder with respect to the crankshaft.

In this lawn mower, the crankshaft of the engine is installed in the upper part of the housing with the cylinder oriented vertically and the cylinder oriented horizontally, so that an extra space is created in the upper part of the housing on the side opposite to the cylinder.

Therefore, by locating the operating member of the clutch device in this part, the extra space can be used effectively, and the operating member can be arranged without interference with other members.
In addition, by making a large movement of the operating member, reliable latching/disconnecting operation can be expected.

In a walk-behind lawn mower having an operating handle extending rearward from the mower body, by arranging the cylinder toward the handle, the vibration of the handle caused by the reciprocating movement of the piston is reduced. The steering operation of the aircraft body using the handle becomes easy.

FIG. 1 is a side view of a walk-behind lawn mower according to an embodiment of the present invention, and FIG. 2 is a partial top view thereof. Reference numeral 1 denotes the main body of the lawn mower, which is supported so as to be movable by four wheels 2 on the front, rear, left and right sides. The main body 1 is covered with a cutter housing 3 at the bottom and an engine cover 4 at the top. An engine 5 and its attached devices are housed within the engine cover 4.

6 is a crankshaft, 7 is a piston, and 8 is a cylinder.

As can be seen from the figure, the engine 5 is mounted with the cylinder 8 horizontally oriented substantially in the longitudinal direction and the crankshaft 6 oriented vertically. Inside the cutter housing 3, a cutter blade 9 and a fan 10, which are driven and rotated by a crankshaft 6 which is a power extraction shaft of an engine 5, are disposed vertically on the same axis as the power extraction shaft.
The grass cut by the rotation of the fan 10 is conveyed through the conveyance path 11 formed along the inner peripheral surface of the cutter housing 3 to the discharge port 12 opened at the rear of the main body 1 by the conveyance wind generated by the rotation of the fan 10. It is transported and stored in a glass bag 13 connected to the outlet 12.

The above-mentioned "on the same axis as the power take-off shaft J" also includes cases where the blades or the fan are pivotally supported on a fixed member such as a housing or an engine case via a bearing.

14 on both sides of the rear upper part of the main body 1.
is fixed at its front end and extends upward and backward,
A handle portion 14c is provided at the rear end to connect the left and right handle members 14a, 14b. The operator uses this handle part 14.
Steer the main body 1 by placing your hand on c.

The upper part of the glass bag 13 is attached to a handle 14.

Since the cylinder 8 of the engine 5 is oriented in the longitudinal direction, that is, in substantially the same direction as the extension direction of the handle 14, the vibration of the handle 14 (7) caused by the reciprocating movement of the piston 7 is small, and the handle 14 Steering operation of the main body 1 is easy.

Next, a power transmission mechanism between the crankshaft 6, cutter blade 9, and fan 10 will be explained with reference to FIG. As mentioned above, the crankshaft 6 arranged in the vertical direction penetrates the crankcase 15 of the engine via the main bearing 16 and projects downward, and passes through the opening 17 provided in the cutter housing 3 into the housing 3. It extends to form a power take-off shaft 18. A first pulley 19 which also serves as a clutch is provided in the housing 3 above the power take-off shaft. This pulley is divided into upper and lower pulley halves 19a and 19b, and the upper pulley half 19a is fixed to the power take-off shaft 18, while the lower pulley half 19b is connected to the power take-off shaft via a bearing 20. 18 so as to be rotatable. The boss portion 21 of the pulley half body 19b is connected to the power take-off shaft 1 in the axial direction.
A cutter blade 9 is fastened to the lower surface of the boss portion 21 by a screw 22. An annular projection 23 is provided in the middle of the inner hole of the boss portion 21, and the projection 23 is held between the upper and lower bearings 20, 20. Since the upper bearing 20 is in contact with the lower end surface of the pulley half body 19a, the bearing 20 and the protrusion 23 are integrally attached to the pulley half body 19a by a bolt 24 that is screwed onto the power take-off shaft 18 from the lower end surface. By tightening,
The pulley halves 19a and 19b are held at a predetermined interval,
One pulley having a v-shaped annular groove on its circumferential surface is formed.

A pulley support shaft 25 is provided in front of the power take-off shaft 18 and parallel to the shaft.
(see FIG. 4) is suspended from the upper wall of the cutter housing 3, and a second pulley 26 is pivotally supported on this pulley support shaft 25 via a bearing.
A V-belt 28 is wound between the first boot 1J19 and the first boot 1J19. The V-belt 28 can be tensioned and relaxed by a tension pulley as will be described in more detail later, and when relaxed, the V-belt 28 is
Since the pulley 19 is placed on the engagement slope of the lower pulley half 19b and separated from the engagement slope of the upper pulley half 19a, the power of the power take-off shaft 18 is transferred to the pulley half 19b and thus to the cutter blade 9. is not transmitted, but when tension is applied, the V-belt 28 is uniformly pressed against the engaging slopes of the upper and lower pulley halves 19a and 19b, so the power of the power take-off shaft 18 is transferred from the pulley half 19a to the pulley via the V-belt 28. half body 1
The power is transmitted to the first pulley 9b to drive the cutter blade 9, and at the same time, the power is transmitted from the first pulley 9 to the second pulley 26.

A third boolean 1J29 is integrally formed at the lower part of the second pulley 26. On the other hand, on the power take-off shaft 18 side, a fourth pulley 31 is rotatably provided on the outside of the boss portion 21 of the pulley half body 19b via a bearing 30. A belt 32 is wound between them. This belt 32 is always maintained in a power transmitting state (tensioned state). A disc-shaped fan boss 33 is fixed to the lower end surface of the 41st-ri 31 with screws 34, and the fans 10 are fixed with screws 35 at appropriate intervals on the outer circumference of the fan boss 33 and radially outward. It extends to

Thus, in the cutter housing 3, there is a power transmission path from the power extraction shaft 18 to the cutter blade 9 via the pulley half 19a, the V belt 28, and the pulley half 19b, and the first boot 9, the second pulley 26, and the second pulley 26. A power transmission path is formed that passes through the third pulley 29 and the fourth pulley 31 and reaches the fan 10, and both transmission paths are simultaneously interrupted or disconnected by loosening or tensioning the V-belt 28. Furthermore, each pulley 19.26.29.3
The diameter of the first pulley 19 is selected so that the rotation of the first pulley 19 is decelerated and transmitted to the fourth pulley 731, so that even if the cutter blade 9 is rotated at a high enough speed to cut grass, Since the fan 10 rotates at a slower speed than this, fan noise is significantly reduced.

FIG. 4 is a top view showing a clutch device that loosens and tensions the V-belt 28 to connect and disconnect power transmission. This clutch device includes the aforementioned eleventh pulley 19, second pulley 26 and V-belt 28 as some of its components,
By tensioning or relaxing the V-belt 28 by the swinging tension pulley 36, the clutch action is obtained as described above. In FIG. 4, the state when the V-belt 28 is relaxed is shown by a solid line, and the state when the V-belt 28 is under tension is shown by a chain line. Note that the third pulley 29, fourth pulley 31, and belt 32 located below the clutch device are shown by dotted lines.

The tension pulley 36 is rotatably attached to the tip of one arm piece 37a of an arm member 37, which is L-shaped when viewed from above, via a shaft piece 38 and a bearing 39 (see FIG. 6). . The arm piece 37a is pivotally supported by the cutter housing 3 via a pivot 40 at a position near its base.
The entire arm member 37 rotates around this pivot 40. As can be seen from FIGS. 4 to 6, the arm piece 37a extends in the circumferential direction below the cutter housing 3 at the same height as the blades 9 and 26; The piece 37b extends generally radially outward above the cutter housing 3, so that the connecting portion 37d of the arm pieces 37a, 37b is connected to the hole 4 provided in the cutter housing 3.
1 from bottom to top.

A brake shoe 42 is attached to a screw 4 on the bottom surface of the connecting portion 37c.
3 and protrudes toward the pulley 19.31 side.

The brake shoe 42 is located at a height between the lower surface of the pulley half 19b on the lower side of the first pulley 19 and the upper surface of the fourth pulley 31. A braking surface 44 that is frictionally engaged via the friction piece 42a is formed. When the tension pulley 36 retreats to relax the V-belt 28, the brake shoe 42 moves forward and touches the braking surface 44, as shown by the solid line in FIG.
, and brakes the pulley half 19b and the fourth boolean 1731, that is, the cutter blade 9 and the fan 10, thereby preventing the cutter blade 9 and the fan 10 from rotating when the clutch is released.

A locking piece 45 is provided to protrude upward from the tip of the arm piece 37b. The locking piece 45 has two locking holes 46a, 4.
6b is provided. One end of a brake spring 47 is locked in one of the locking holes 46a, and the arm member 37 is rotated counterclockwise in FIG.
is biased in the direction of engagement with the pulley half 19b and the fourth pulley 31. One end of a clutch spring 48 is locked in the other locking hole 46b and extends to the opposite side of the brake spring 47.
The other end is connected to a clutch cable 49. 50
is a cable holding piece that holds and guides the clutch cable 49, and is attached to the front upper surface of the canter housing 3.

As shown in FIG. 2, the clutch cable 49 slidably inserted into the cable holding piece 50 extends rearward within a sheath pipe 51 disposed around the engine part on the cutter housing 3, and then passes through the handle member 14b. It reaches the rear end along the line and is connected to an operating lever 52 (FIG. 1) provided at the rear end. When the operating lever 52 is operated, the arm member 37 rotates clockwise around the pivot shaft 40 via the clutch cable 49 and clutch spring 48 as shown by the chain line in FIG. Push from the side to tension the belt and bring the clutch device into the connected state. At the same time, the brake shoe 42 separates from the pulley half 19b and the fourth pulley 31 to release the brake, so that the cutter blade 9 and the fan 1o immediately start rotating in response to the operation of the operating lever 52.

Arm piece 37b and locking piece 4 which are operating members of the clutch device
5. Brake spring 47, clutch spring 48
are arranged in the upper part of the cutter housing 3 in front of the engine, that is, on the side opposite to the cylinder 8 with respect to the crankshaft 6, making effective use of the space formed in this part.

Since there is no other member in this part that would obstruct the swinging movement of the operating member, the swinging angle of the arm member 37 is set large and the V-belt 2 is attached to the tension pulley 36.
The tension state and the relaxed state of the brake shoe 8, and the braking state and the released state of the brake shoe 42 are clearly distinguished, and a reliable latching operation can be obtained.

Although a preferred embodiment of the present invention has been described above, the present invention is not limited to this embodiment (it goes without saying that many other modifications are possible within the scope of the present invention. For example, In the above embodiment, the cutter blade 9 and the fan 10 are arranged coaxially with the crankshaft 6, but it is also possible to arrange these on the pulley support shaft 25 side coaxially with the shaft. It is also possible to apply the present invention to a lawn mower having only a canter blade.

As mentioned above, the present invention provides a grass lawn mower in which a cutting section for cutting grass is housed in a housing, and an engine for driving the cutting section is mounted on the upper part of the housing.6. 7. A power transmission device for transmitting engine power from the crankshaft to the cutting section and a clutch device for intermittent power transmission are provided in the housing, the shaft being installed with the shaft in the vertical direction and the cylinder in the horizontal direction, and the clutch device Since the operating member is passed through the upper wall of the housing and is located at the upper part of the housing and on the opposite side of the cylinder with respect to the crankshaft, the extra space in the upper part of the housing can be used effectively, and the operating member can be easily connected to other members. It is possible to arrange the clutch operating member without causing interference, and the movement of the operating member can be set to a large extent to ensure reliable latch/disconnection operation.

In addition, when the lawn mower main body is provided with an operating handle that extends rearward from the main body, by arranging the cylinder toward the handle, vibrations of the handle caused by the reciprocating movement of the piston can be avoided. By making the handle smaller, it is possible to easily steer the aircraft using the handle.

[Brief explanation of drawings]

Fig. 1 is a side view of a walk-behind lawn mower according to an embodiment of the present invention, Fig. 2 is a partial top view thereof, and Fig. 3 is a cross-section of the power transmission device taken along the line ■-■ in Fig. 2. 4 is a top view of the clutch device, FIG. 5 is an elevational view of the arm member of the clutch device viewed from the circumferential side, and FIG. 6 is a radially outward view of the arm member of the clutch device. This is an elevation view seen from the front. l...Body, 2...Wheel, 3...Cutter housing, 4...Engine cover, 5...Engine, 6...
... Crankshaft, 7... Piston, 8... Cylinder, 9... Canter blade, 10... Fan, 11...
...Conveyance path, 12...Discharge port, 13...Glass bag, 14...Handle, 15...Crank case,
16... Main bearing, 17... Opening, 18... Power take-off shaft, 19... First pulley, 20... Bearing, 21...
・・Boss part, 22・・Screw, 23・Protrusion, 24・
...Bolt, 25...Pulley support shaft, 26...Second
Pulley, 28...V belt, 29...Third pulley,
30... Bearing, 31... Fourth pulley, 32... Belt, 33... Fan boss, 34.35... Screw,
36... Tension pulley, 37... Arm member,
38... Shaft piece, 39... Bearing, 40... Pivot,
41...hole, 42...brake shoe, 43...
Screw, 44...braking surface, 45...locking piece, 46...
・Latching hole, 47... Brake spring, 48...
Clutch spring, 49... Franch cable, 5
0... Cable holding piece, 51... Sheath tube, 52...
・Operation lever

Claims (2)

[Claims] (1) In a grass lawn mower in which a cutting part for cutting grass is housed in a housing and an engine for driving the cutting part is mounted on the upper part of the housing, the crankshaft of the engine is oriented vertically and the cylinder is oriented horizontally. and a power transmission device for transmitting engine power from the crankshaft to the mowing section and a clutch device for disconnecting power transmission are provided in the housing, and an operating member of the clutch device is inserted through the upper wall of the housing. The lawn mower is located at the upper part of the housing and on the opposite side of the cylinder with respect to the crankshaft. (2) The lawn mower according to claim 1, wherein the lawn mower body is provided with an operation handle extending rearward from the body, and the cylinder is disposed toward the handle.