GB2279995A

GB2279995A - Engine body cover

Info

Publication number: GB2279995A
Application number: GB9413639A
Authority: GB
Inventors: Tadayuki Yoneyama; Toshifumi Kouchi; Masahiro Anzai; Tsutomu Arai; Shuhei Imai
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1993-07-06
Filing date: 1994-07-06
Publication date: 1995-01-18
Anticipated expiration: 2014-07-06
Also published as: GB2279995B; GB9413639D0

Abstract

The two-stroke engine E has a cover 1 in two separable parts (45, 46, Fig. 3) one on each side of the axis of the cylinder barrel 16. Cooling air inlet ports (69, Fig. 4) are defined between the rear ends of the cover parts and the support post 31 for the steering handles (4, Fig. 2) and exhaust ports 71 are provided at the front of each cover part. An air filter housing (86, Fig. 7) is formed in one of the synthetic resin cover parts and a cover (88) retains a filter element (87). A synthetic resin fuel tank 68 is located at the rear of the engine E and includes a peripheral groove (682, Fig. 11) receiving edges (452, 462) of the cover parts. <IMAGE>

Description

WORKING MACHINE This invention relates to a working machine, particularly although not exclusively a soil working machine, including a power take-off shaft connected to working section and projecting downwardly from an engine body.

Japanese Patent Publications Nos. 29771/93 and 26263/88 disclose working machines in which a periphery of an engine for the working machine is covered with an engine cover.

In the working machine described in Japanese Patent Publication No. 29771/93, the engine cover for covering the engine body is composed of three components, i.e. two cylindrical central portions integrally coupled to each other at a central dividing face, an end face-side portion for closing an opening at one end of the central portion, and a lid portion for closing an opening at the other end of the central portion.

In the working machine described in Japanese Patent Publication No. 26263/88, the engine cover includes three components: a cylindrical central portion for covering the engine body, an end face-side portion and a lid portion for openings in opposite ends of the central portion, respectively.

Because the engine cover includes four or three components in the known working machines mentioned above, these machines suffer not only from the problem that an increased number of parts is required, but also from the problem that, even if the end face-side portion or the lid portion is removed from the central portion, the engine body is still some distance from the opening, resulting in difficult maintenance.

According to the present invention, there is provided a working machine comprising an engine body provided with a downwardly directed power take-off shaft connected to a working section, wherein the engine body includes a cylinder barrel disposed with its axis extending longitudinally with respect to the intended direction of operative travel of the working machine, the engine body and intake and exhaust auxiliaries provided on the engine body being covered by an engine cover which is laterally divided into a left cover portion and a right cover portion and which is provided with a cooling-air intake port and a cooling-air discharge port.

With a working machine constructed in accordance with the present invention, since the engine cover which covers the engine body and the intake and exhaust auxiliaries is divided laterally into the two portions, mud cannot be deposited onto the engine, and dust cannot be drawn into the intake system. Also, the noise of the engine can be shielded by the engine cover, leading to a reduced noise volume. Moreover, the number of parts making up the engine cover can be minimized, to improve the ease of assembly and maintenance. In addition, since the axis of the cylinder barrel is disposed in the longitudinal direction within the engine cover, the engine cover can have a small width to provide a smart appearance and moreover to improve the handling property in a cultivation area which is narrow at engine height.

Further, the provision of the cooling-air intake and discharge ports in the engine cover allows for a cooling of the engine without hindrance.

The engine body may further include a crank case, and the machine may also have a fuel tank and a muffler. The cylinder barrel, the crank case and the fuel tank may be disposed longitudinally in sequence from the front to the rear in the intended direction of operative travel of the working machine. An air cleaner may be disposed below the fuel tank. With such a construction, the engine body and the auxiliaries can be arranged longitudinally to possibly reduce the lateral width of the working machine. Thus, it is possible to perform an efficient working in a narrow area, for example between crop rows as in a tea plantation, while avoiding the contact of a portion, near the engine body, of the working machine having substantially the same height as the crop, such as a tea bush with tea leaves.

A steering handle bar may be mounted to the rear of the engine peripherally covered with the engine cover, and the cooling-air discharge port may be defined in a front portion of the engine cover. With such a construction, cooling air having an increased temperature cannot blow against an operator using the steering handle bar behind the cooling-air discharge port, or against crops growing to the side of the working section. Moreover, since the engine is covered by the engine cover, mud cannot be deposited on the engine, but also the noise of the engine can be shielded, leading to a reduced noise volume.

With a construction wherein the engine is attachable to and detachable from the working section and the steering handle bar, and a carrying handle is provided above the engine, it is possible to remove the engine from the working machine for use in another application. Also, the handle makes it easy to carry either the engine alone or the entire working machine by an operator grasping the carrying handle. Moreover, if the carrying handle projects above the engine, it provides a useful sighting aid, so that operative travel of the working machine can be determined using the carrying handle as a guide, whereby the operator can easily maintain a straight travel path and can easily correct deviations from the desired direction.

The engine body and an area in the vicinity of an intake bore defined in the air cleaner case may be covered with the engine cover, and an air intake port may be defined in such a portion of the engine cover which is located on the opposite side of the air cleaner case from the intake bore. With such a construction, air drawn into the engine cover through the air intake port is forced to flow through a bypass path around the air cleaner, and is introduced into the air cleaner case through the intake bore defined opposite from the air intake port. Therefore, dust entrained in the air is dropped during flowing of the air, so that clean air can be introduced into the air cleaner.

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Fig. 1 is a side view of a cultivator; Fig. 2 is a view taken along the arrow 2 in Fig.

1; Fig. 3 is a view taken along the line 3-3 in Fig.

1; Fig. 4 is an enlarged view taken in a direction indicated by an arrow 4 in Fig. 1; Fig. 5 is an enlarged view of a portion of the cultivator as shown in Fig. 2; Fig. 6 is an enlarged sectional view taken on the line 6-6 in Fig. 2; Fig. 7 is a sectional view taken along the line 7-7 in Fig. 6; Fig 8 is a sectional view taken along the line 8-8 in Fig. 6; Fig. 9 is a sectional view taken along the line 9-9 in Fig. 6; Fig. 10 is a sectional view taken along the line 10-10 in Fig. 6; Fig. 11 is a sectional view taken along the line 11-11 in Fig. 6; Fig. 12 is a sectional view taken along the line 12-12 in Fig. 6; Fig. 13 is a sectional view taken along the line 13-13 in Fig. 6; and Fig. 14 is a view showing the cultivator carried by an operator.

Referring to Figs. 1 to 4, a walking type cultivator T as a working machine includes an engine cover 1 made of synthetic resin for covering an outer periphery of an engine. A cultivator section R constituting a working section is mounted below the engine cover 1 by means of a steering handle bar mounting member 2 and a transmission case 3. A steering handle bar 4 is mounted on an upper end of the steering handle bar mounting member 2 and extends rearwardly and upwardly. The cultivating section R incudes a cultivating shaft 5 extending laterally, and a pair of left and right inner rotors 6 and a pair of left and right outer rotors 7, both of which are mounted on the cultivating shaft 5. Each of the inner rotors 6 has four cultivating blades 61 and 62. Two of these cultivating blades 61 are directed laterally inwardly, and the other two cultivating blades 62 are directed laterally outwardly. Each of the outer rotors 7 has four cultivating blades 71 which are directed laterally inwardly. The steering handle bar 4 is Ushaped and is provided at its lower end with a joint 8 which is releasably fixed to an upper end of the steering handle bar mounting member 2. Handle grips 11 are mounted at an upper end of the steering handle bar 4, and a throttle lever 13 is mounted on one of the handle grips 11 and connected to a carburettor throttle of the engine through a throttle cable 12. The throttle cable 12 is connected to the carburettor throttle through cooling-air intake ports 69 provided between a handle post 31 and engine cover portions 45 and 46, which will be described later.

As shown in Fig. 6, the engine E is a singlecylinder 2-stroke engine and includes an engine body 17 which includes a crank case 15 and a cylinder barrel 16. The engine body 17 is disposed longitudinally with the cylinder barrel 16 located to the front and the crank case 16 located to the rear. A carburettor 18 is mounted on a rear surface of the crank case 15, and recoil starter 20 is mounted on an upper surface of the crank case 15 and includes a knob 19 (see Fig. 5) which is exposed to the outside of the engine. An air duct 21 is integrally formed at a lower portion of the engine body 17 and includes an inlet opening 211 at the rear portion of the crank case 15 on the left and right sides, an intermediate opening 212 located at the lower portion of the cylinder barrel 16, and an outlet opening 213 located at an upper portion of the cylinder barrel 16.

The engine E is supported on an engine bed 22 having an open upper surface. A crank shaft 24 projects downwardly from the crank case 15 of the engine E and is supported on a ball bearing 23, and a flywheel 25 and an automatic centrifugal clutch 26 are supported on the crank shaft 24, so that they are located within the engine bed 22. An annular cooling fan 27 is mounted on an upper surface of the flywheel 25, opposite the inlet opening 211 and the intermediate opening 212 in the air duct 21.

The steering handle bar mounting member 2 includes a mounting plate 29 fixed to a lower surface of the engine bed 22 by bolts 28, a tubular transmitting/connecting member 30 mounted on a lower surface of the mounting plate 29 to project downwardly, a tubular handle post 31 extending rearwardly and upwardly from a rear portion of the mounting plate 29, and a connecting/reinforcing plate 32. The plate 32 integrally couples the lower surface of the mounting plate 29, a rear surface of the transmitting/connecting member 30 and a front surface of a lower end of the handle post 31 at its lower end.

As can be seen from Fig. 4, the connecting/reinforcing plate 32 functions to reinforce the steering handle bar mounting member 2 to provide for a firm supporting of the steering handle 4. Since the connecting/reinforcing plate 32 is located between the opposed blades 61 of the left and right inner rotors, the plate 32 also functions to dislodge small stones S and clods which are jammed between such opposed left and right blades. Thus, it is possible to effectively prevent a sticking of the inner rotors during cultivation, but also to prevent the transmission case 3 and the transmitting/connecting member 30 from being damaged by the impact of small stones S.

Returning to Fig. 6, the transmission case 3 is mounted on the lower end of the transmitting/connecting member 30 of the steering handle bar mounting member 2 through a coupling member 33, and a cylindrical worm 35 is supported within the transmission case 3 with a pair of upper and lower ball bearings 34 interposed therebetween. The cylindrical worm 35 is connected through a transmission shaft 38 to a power take-off shaft 37 of the automatic centrifugal clutch 26 supported by a ball bearing 36, and is meshed with a worm wheel 39 which is provided on the cultivating shaft 5 carrying the inner rotors and the outer rotors 7. Thus, driving power from the engine E is transmitted through the crank shaft 24, the automatic centrifugal clutch 26, the transmitting shaft 38, the cylindrical worm 35 and the worm wheel 39 to the cultivating shaft 5 to drive the inner rotors 6 and the outer rotors 7 provided on the cultivating shaft 5.

The cylindrical worm 35 and the worm wheel 39 constitute a worm gear.

As can be seen from both of Figs. 6 and 13, a resisting bar mounting member 40 having a U-shaped section is welded to a rear surface of the handle post 31 and has an L-shaped resisting bar 41 supported on the resisting bar mounting member 40. The resisting bar 41 includes a mounting portion 411 slidably fitted in the resisting bar mounting member 40, and a resisting portion 412 extending rearwardly and downwardly from the mounting portion 411. The resisting bar 41 is fixed so that its vertical position can be adjusted, by inserting a pin 42 through a pin hole 401 in the resisting bar mounting member 40 and through any one of a plurality of pin holes 413 defined in the mounting portion 411. With the resisting bar 41 fixed to the resisting bar mounting member 40, a front surface of the mounting portion 411 is in close contact with a rear surface of the handle post 31 (see Figs. 1 and 6). This permits a load received by the resisting portion 412 of the resisting bar 41 to be transmitted directly to the handle post 31, and hence, the resisting bar 41 can be supported firmly in a simple structure comprising a smaller number of parts.

The structure of the engine cover 1 covering the engine E will be described below.

The engine cover 1 made of synthetic resin is composed of a left cover portion 45 and a right cover portion 46 which are divided along a centre line extending longitudinally in the intended direction of operative travel of the machine. The left cover portion 45 and the right cover portion 45 are socketfitted to each other at mating faces on their outer peripheries and integrally coupled to each other by five bolts 47 to 51 (see Fig. 6). A carrying handle 52 is integrally formed on the upper portion of the engine cover 1 so that an operator can carry the cultivator T by hand.

As can be seen from Figs. 6 and 8, a stay 55 is fixed to a wall surface of a front portion of the crank case 15 through three bolts 53 and a connecting member 54. The stay 55 has a locking portion 551 formed at an upper end thereof to engage a pair of boss portions 56 and 57 projectingly provided in an inner surface of the engine cover 1. The left and right cover portions 45 and 46 are supported on the stay 55 by the bolt 47 passing through one of the boss portions 56. As can be seen from Figs. 6 and 7, a stay 58 is mounted on an upper wall surface of a rear portion of the crank case 15 from which it extends upwardly, and the left and right cover portions 45 and 46 are supported on the stay 58 by the bolt 48 passing through the stay 58 and the boss portion 59 projectingly provided on the inner surface of the engine cover 1. Thus, the upper portion of the engine cover 1 is supported on the engine body 17 through the two bolts 47 and 48 and the two stays 55 and 58.

As can be seen from Figs. 6 and 10, upper ends of rear portions of the left and right cover portions 45 and 46 are integrally coupled by the bolt 49 passing through boss portions 60 projectingly provided on inner surfaces of the cover portions 45 and 46. Further, as can be seen from Figs. 6 and 9, a bracket 221 having a downwardly opened groove is projectingly mounted at a front end of the engine bed 22, and the left and right cover portions 45 and 46 are integrally coupled by the bolt 50 with ribs 61 fitted into the groove in the bracket 221. Likewise, ribs 62 of the left and right cover portions 45 and 46 are fitted into grooves in a bracket 222 projectingly mounted at a rear end of the engine bed 22. Thus, the rear portions of the left and right cover portions 45 and 46 are integrally coupled by the single bolt 49, and further, lower portions of the left and right cover portions 45 and 46 are supported on the engine bed 22 by the two bolts 50 and 51.

By completely covering the engine E with the engine cover 1 which is laterally divided into the two portions, as described above, the number of parts can be reduced, as compared with the case where the engine E and auxiliaries thereof are covered with separate covers. Moreover, a sealing of the mating faces can easily be performed. Further, it is possible to reduce the level of noise of the engine E reaching the outside and to prevent mud and dust from being deposited onto the engine E, and moreover, it is possible to provide an improved appearance.

As can be seen from Fig. 1, the centre of gravity CG of the cultivator T is located behind and below the carrying handle 52. Therefore, when the operator carries the cultivator T by grasping the carrying handle 52, as shown in Fig 14, the laterally wide cultivating section R is located in front of an operator's body, so that contact of the operator's body with the cultivating section R is avoided, making it easier for the operator to carry the cultivator T. In addition, the engine E covered with the engine cover 1 can be removed from the steering handle bar mounting member 2, the transmission case 3, the cultivating section R, the steering handle 4 and the resisting bar 41 by releasing the nuts 281 threadedly fitted over the bolts 28 to separate the steering handle bar mounting member 2 from the engine bed 22, as can be seen from Fig. 6. This allows the same engine E to be used not only in the cultivator T, but also in a lawn mower, a sweeper, a grass mower, a chain saw and the like. Even when the engine E has been removed, the carrying of the engine E can easily be performed by utilizing the carrying handle 52. In addition, since the flat engine bed 22 is located on the lower surface of the engine cover 1, the engine E can be stably placed on a ground surface or a floor surface without tipping or turning upside-down.

The structure for cooling the engine E mounted within the cover 1 will be described below.

As shown in Figs. 5 and 6, a muffler 65 with an exhaust port 651 directed forwardly, an exhaust pipe 66, the cylinder barrel 16, the crank case 15, the carburettor 18 and an air cleaner 67 are disposed in sequence from the front to the rear within the engine cover 1 which is composed of the left and right cover portions 45 and 46. A fuel tank 68 is disposed above the carburettor 18 and the air cleaner 67, so that an upper half thereof is exposed from the engine cover 1.

As described above, the engine body 17 is vertically placed, so that the cylinder barrel 16 and the crank case 15 are located longitudinally. The muffler 65 and the fuel tank 68 are disposed in front of and to the rear of the cylinder barrel 16, respectively, and the carburettor 18 and the air cleaner 67 are disposed below the fuel tank 68.

therefore, it is possible to reduce the lateral width of the engine E including auxiliaries, i.e. the lateral width of the engine cover 1. As a result, when working is to be conducted in a narrow space such as in a tea plantation, efficient working can be achieved while avoiding the contact of the machine with the crop.

A vertically extending opening is provided between the mating faces of the left and right cover portions 45 and 46 at the rear end of the engine cover 1, and a lower half of the handle post 31 is fitted in this opening. A pair of left and right cooling-air intake ports 69 are defineS between the handle post 31 and the end edges of this opening (see Figs. 5 and 10), respectively. Ribs 70 are provided to protrude inwardly from a lower portion of the opening into proximity to an outer periphery of the handle post 31, so that the flow of air is inhibited. Thus, the air intake ports 69 are opened at a relatively high location (between the resisting bar mounting member 40 and the bolt 49 fastening the engine cover 1) at the rear end of the engine cover 1. Thus, in drawing cooling-air into the engine cover through the air intake ports 69, clean air containing little dust can be drawn into an area upwardly spaced apart from the cultivating section R. On the other hand, louvre-like cooling-air discharge posts 71 are defined at a front end of the engine cover 1, and the exhaust port 651 in the muffler 65 is situated opposite a hole defined below the discharge ports 71.

Since the cooling-air intake ports 69 are defined between the rear ends of the left and right cover portions 45 and 46, as described above, when the left and right cover portions 45 and 46 are molded from a resin in a mold, the cooling-air intake ports 69 can be formed by a mold of a simple structure without any machining after the molding.

As can be seen from Figs. 6 to 8, vertically extending partition walls 72 and 73 are integrally formed on inner surfaces of the left and right cover portions 45 and 46, respectively. The partition wall 72 formed on the left cover portion 45 has a shape conforming at its upper portion to a contour of the stay 55 and extends downwardly at a substantially constant distance spaced apart therefrom. On the other hand, the partition wall 73 formed on the right cover portion 46 has a shape conforming at its upper portion to a contour of the stay 55 and extends downwardly along a boundary between the crank case 15 of the engine body 17 and the cylinder barrel 16. The inside of the engine cover 1 is divided by the partition walls 72 and 73 into a rear chamber 74 adjacent the coolingair intake ports 69 and a front chamber 75 adjacent the cooling-air discharge ports 71 (see Fig. 6). The inlet opening 211 in the air duct 21 is opened into the rear chamber 74, and the outlet opening 213 in the air duct 21 is opened into the front chamber 75.

Thus, when the cooling fan 27 integral with the flywheel 25 mounted on the crank shaft 24 of the engine E is rotated, air drawn through the cooling-air inlet ports 69 by the resulting reduced pressure is passed into the rear chamber 74 to cool the fuel tank 68, the carburettor 18 and the crank case 15 and then passed into the air duct 21 through the inlet opening 211 to cool the automatic centrifugal clutch 26.

Subsequently, the cooling-air is passed through the intermediate opening 212 in the air duct 21 to cool the cylinder barrel 16; passed into the front chamber 75 through the outlet opening 213 to cool the exhaust pipe 66 and the muffler 65, and discharged through the cooling-air exhaust ports 71 to the outside of the engine cover 1.

As described above, the fuel tank 68 and the carburettor 18 at a low temperature are disposed adjacent the cooling-air intake ports 69. The crank case 15 and the automatic centrifugal clutch 26 at a middle temperature are disposed more downstream, and the cylinder barrel 16, the exhaust pipe 66 and the muffler 65 at a high temperature are disposed further downstream. Therefore, heat from the cylinder barrel 16, the exhaust pipe 66 and the muffler 65 is kept away from the fuel tank 68 and the carburettor 18. Also, even though the temperature of the cooling air gradually rises along its flow path, a difference in temperature between the portions to be cooled and the cooling air can be always ensured to effectively cool all of the portions to be cooled. Moreover, the cooling air is drawn through the rear portion of the machine at which an operator stands, and the exhaust gas and the cooling air at increased temperature are discharged forwardly through the front portion of the machine opposite from the operator. This avoids the danger of the exhaust gas and the cooling air at a high temperature blowing against the operator to degrade the working environment or blowing against crops to damage them.

The structure for supporting the fuel tank 68 will be described below.

As shown in Fig. 6, the fuel tank 68 is integrally formed from a synthetic resin, and has a fuel supply port 681 defined in an upper surface thereof. A lower portion of the fuel tank 68 and the carburettor 18 are interconnected through a fuel tube 81, and a fuel cock 82 is provided in the middle of the fuel tube 81. As shown in Figs. 10 and 11, a recessed groove 682 having a U-shaped section is defined around an outer periphery of the fuel tank 68. A portion of the fuel tank 68 below the recessed groove 682 is covered with the engine cover 1, and a portion above the groove 682 is exposed upwardly from the engine cover 1. It should be noted that a rear portion of the recessed groove 682 is not U-shaped in section and opened at an underside thereof (see a right-hand sectional portion in Fig.

11).

As can be seen from Fig. 10, a grommet 83 is fitted over a support pin 461 projecting from the right cover portion 46 and retained in a support hole made in the left cover portion 45. The grommet 83 is fitted into a front end of the recessed groove 682. A pair of left and right grommets 84 are retained on an outer periphery of the boss portions 60 projectingly mounted on the inner surface of the engine cover 1 and are fitted into a recess 683 defined in a rear and lower portion of the fuel tank 68. Further, a pair of projections 684 are provided on left and right opposite sides of the fuel tank 68 and fitted into a pair of rubber bushes 85 retained on the inner surfaces of the left and right cover portions 45 and 46, respectively (see Fig. 12). The fuel tank 68 is located longitudinally by the three grommets 83 and 84 and laterally by the two rubber bushes 85, and is supported in a floating manner on the engine cover 1 by the grommets 83, 84 and the rubber bushes 85. Thus, it is possible to effectively prevent the transmission of vibration from the engine E to the fuel tank 68, while stably supporting the fuel tank 68 by a smaller number of parts.

As can be seen from Fig. 11, portions near the end edges 452 and 462 of the left and right cover portions 45 and 46 which surround the opening defined therein in order to permit the upper half of the fuel tank 68 to protrude upwardly from the engine cover, are bent inwardly and upwardly, and fit loosely in the recesses groove 682 of the fuel tank 68. A water-drip rib 685 is projectingly provided in a downwardly directed manner on a lower surface of an upper wall of the recessed groove 682 over the entire length of the recessed groove 682. The water-drip rib 685 is located outside the end edges 452 and 462 of the left and right cover portions 45 and 46 of the left and right cover portions 45 and 46, so that waterdrops flowing down along a sidewall of the fuel tank 68 and any fuel leaking through the fuel supply port 681 in the fuel tank 68 are blocked and dropped down by the water-drip rib 685 and prevented from flowing past the end edges and and 462 into the engine cover 1 (see arrows A in Fig. 11).

The structure of the air cleaner 67 will be described below.

As shown in Figs. 6 and 7, the air cleaner 67 includes an air cleaner case 86, an air cleaner element 87 and an air cleaner cover 88. The air cleaner case 86 has a cup-like shape with a circular section and is integrally provided on a side of the rear portion of the left cover portion 45 to project inwardly therefrom. The air cleaner case 86 has an opening covered with the air cleaner cover 88 which is detachable from the outside of the left cover portion 45. A dirty chamber 89 is defined outside the air cleaner element 87 accommodated within the air cleaner case 86, while a clean chamber 90 is defined inside the air cleaner element 87.

A boss 91 is projectingly provided on the inner side of the left cover portion 45 for supporting the fuel cock 82. An upper partition rib 92 is formed between the air cleaner case 86 and the inner surface of the upper portion of the left cover 45, and a lower partition rib 93 is formed between the air cleaner case 86 and the boss 91. A pair of intake passages 861 are defined in the air cleaner case 86 to communicate with the dirty chamber 89, so that it is located in front of the upper and lower partition ribs 92 and 93. The clean chamber 90 is connected to the carburettor 18.

Thus, air drawn through the cooling-air intake ports 69 by a reduced pressure generated by the cooling fan 27 is blocked by the upper and lower partition ribs 92 and 93, so that it cannot flow directly into the intake bores 86; in the air cleaner case 86. Thus, the air is forced to flow along an extended path into the right cover portion 46, to the front of the upper and lower partition ribs 92 and 93 and then in a backward direction through the intake passages 861 into the dirty chamber 89. As the air flows to the air cleaner 67 along the extended path, dust entrained in the air is dropped out, so that relatively clean air is supplied into the air cleaner 67. This makes it possible to prevent premature clogging of the air cleaner element 87 so that it will remain serviceable for longer. The air flowing into the dirty chamber 89 is passed through the air cleaner element 87 where it is completely cleared of dust, and then supplied through the clean chamber 90 into the carburettor 18.

Even if water enters the engine cover 1 from the periphery of the fuel tank 68, the water is blocked by the upper and lower partition ribs 92 and 93 provided in the left cover 45, so that it cannot flow into the intake passages 861 in the air cleaner case 86. This makes it possible to prevent the water from being deposited onto the air cleaner element 87 to cause a clogging of the element 87.

Because the air cleaner is formed integrally with the left cover portion 45 as described above, the number

Claims

1. A working machine comprising an engine body provided with a downwardly directed power take-off shaft connected to a working section, wherein the engine body includes a cylinder barrel disposed with its axis extending longitudinally with respect to the intended direction of operative travel of the working machine, the engine body and intake and exhaust auxiliaries provided on the engine body being covered by an engine cover which is laterally divided into a left cover portion and a right cover portion and which is provided with a cooling-air intake port and a cooling-air discharge port.

2. A working machine according to claim 1, in which an air cleaner is mounted on one of the cover portions, the other cover portion being attachable to and detachable from that one cover portion.

3. A working machine according to claim 2, in which an air cleaner case is integrally formed on the engine cover.

4. A working machine according to any one of the preceding claims, in which a cooling-air intake port is defined between rear end portions of the cover portions.

5. A working machine according to any one of the preceding claims, further including a fuel tank and a muffler, the fuel tank, the engine body and the muffler being disposed in sequence from the rear to the front in the intended direction of operative travel of the working machine.

6. A working machine according to claim 5, in which the engine body includes a crank case, the muffler, the cylinder barrel, the crank case and the fuel tank being disposed longitudinally in sequence from the front to the rear in the intended direction of operative travel of the working machine, an air cleaner, or the air cleaner, being disposed below said fuel tank.

7. A working machine according to claim 5 or 6, in which the engine body, the muffler, the air cleaner and a portion of the fuel tank are covered by the engine cover.

8. A working machine according to any one of the preceding claims, in which a steering handle bar is provided behind the engine body peripherally covered with the engine cover, the cooling-air intake port being defined at a rear portion of the engine cover, and the cooling-air discharge port being defined in a front portion of the engine cover.

9. A working machine according to claim 8, in which the cooling-air intake port is formed between mating faces of rear ends of the cover portions, and a handle post is disposed in the cooling-air intake port for supporting the steering handle bar.

10. A working machine according to claim 9, in which the cooling-air intake port is defined between upper portions of the mating faces of the rear ends of the cover portions.

11. A working machine according to any one of the preceding claims, in which the engine body is detachably mounted to the working section and a steering handle bar, a carrying handle being provided above the engine body.

12. A working machine according to claim 11, in which the engine body and a clutch are supported on an engine bed, the engine body being releasably coupled to a steering handle bar mounting member which is fixed to an upper portion of the working section.

13. A working machine according to claim 11 or 12, wherein the engine cover is made of resin, the carrying handle being integrally formed on the engine cover.

14. A working machine according to any one of claims 11 to 13, in which the carrying handle is provided in front of and above the centre of gravity of the machine.

15. A working machine according to any one of the preceding claims, in which the air cleaner case, or an air cleaner case, has an intake passage defined therein, a region in the vicinity of the intake passage being covered by the engine cover, an air intake port being defined in a portion of the engine cover which is situated on an opposite side of the air cleaner case from the intake passage.

16. A working machine according to claim 15, in which a handle post is fitted into the air intake port for supporting a steering handle bar, said engine body is supported above the working section, and air is drawn through between the handle post and the engine cover.

17. A working machine substantially as described herein with reference to, and as shown in, the accompanying drawings.