GB2142512A

GB2142512A - Cultivators

Info

Publication number: GB2142512A
Application number: GB08412130A
Authority: GB
Inventors: Gunji Saito; Shoichi Kojima; Tomoichiro Takasaki; Hiroshi Takahashi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1983-05-13
Filing date: 1984-05-11
Publication date: 1985-01-23
Also published as: GB8412130D0; GB2142512B; FR2545678B1; FR2545678A1

Abstract

A versatile cultivator is provided wherein a transmission mechanism (T) for transmitting the power of an engine (E) to a cultivating mechanism (11) is operatively connected a power take-off shaft (13) which projects from a lower front portion of a transmission housing (4) accommodating the transmission mechanism (T). A running wheel unit (U) can be removably attached to the lower front portion of the transmission housing, the wheel unit having running wheels (25) rotatably mounted on lateral sides of the front end thereof, and being provided with an interlocking mechanism 21 for linking the running wheels to the power take-off shaft. The cultivator can be used with or without the running wheel unit. <IMAGE>

Description

SPECIFICATION Cultivators This invention relates to cultivators. Herein references such as "front" and "rear" will be made with respect to the intended direction of forward running of the cultivator being referred to.

In general, a cultivator is known as an agricultural machine powered by an engine, which breaks up and plows lands and fields, and prepares the soil for planting. It is desirable that such a cultivator has high versatility and can be used for several purposes so that, for instance, its mode of use can be easily shifted, such as between rough plowing and fine plowing, according to the conditions of the ground being tilled, purpose of use, etc.

According to the present invention there is provided a cultivator comprising a body portion, an engine mounted in the body portion, a transmission housing extending downward from the engine, a cultivator shaft which extends substantially horizontally and laterally through a lower portion of the transmission housing and on which is mounted a cultivting mechanism including tiller tines, and a transmission mechanism housed in the transmission housing and linking the outut end of the engine to the cultivator shaft so that the cultivating mechanism is driven by the engine, wherein a power take-off shaft linked to the transmission mechanism projects from a lower front portion of the transmission housing.Such a cultivator, which has a simple structure, is a Rototiller but by the provision of the power take-off shaft which is linked to the transmission mechanism, the cultivator can further comprise a running wheel unit having a pair of running wheels rotatably mounted on lateral sides of a front end thereof, which unit can be removably secured to the lower front portion of the transmission housing, the running wheel unit being provided therein with an interlocking mechanism which interlocks the power take-off shaft with the running wheels, when the unit is secured to the transmission housing. With the running wheel unit so secured to the transmission housing the cultivator can be used as a rotary cultivator that is self-propelled, without modifying the essential plowing mechanism of the cultivator as a Rototiller.

The present invention also proposes a cultivator as defined above in which, in order to increase the stability of the cultivator for facilitating plowing and to simplify the operation of changing its running direction, the running wheels when fitted are so designed that their ground-contact point is positioned forward of an extension of the line connecting the center of gravity of the cultivator body portion to handle grips.

The present invention further proposes a cultivator as defined above in which the axle of the running wheels when fitted is located forward of a frontguard provided on the front of the cultivator body portion to protect the body portion against any obstacles lying in front thereof, so as to enable forward tilting of the cultivator to a larger extent when its running direction is being changed so that when, for inst ance, the cultivator is turned at a point facing a mound of earth or a furrow, an easy and smooth turn can be made without the cultivator being hindered by or damaging such an obstacle.

The invention also proposes use of a reinforcing bar for connecting between the front end of the wheel unit and an upper part of the cultivator body portion to augment its wheel-supporting strength.

These and other objects, features and advantages of the present invention will become apparent from the following detailed description of an embodiment thereof, in conjunction with the accompanying draw ings.

The drawings illustrate an embodiment of the present invention, in which: Figure 1 is a persepctive view of a Rototiller as an embodiment of the present invention.

Figure 2 is an enlarged, partially-sectioned view of the cultivator of Figure 1.

Figure 3 is a perspective view of a rotary cultivator as embodied by the invention.

Figure 4 is an enlarged, partially-sectioned view of the cultivator of Figure 3.

Figure 5 is a side view of a modified form of the rotary cultivator of Figures 3 and 4.

Figure 6 is a side view of another modified form of the rotary cultivator of Figures 3 and 4.

Figure 7 is a side view of the cultivator of Figure 6 shown tilted forward.

The present invention will now be described in detail with reference to an embodiment as well as some modifications thereof illustrated in the drawings where identical or corresponding parts are assigned identical reference characters throughout.

In the drawings, Figures 1 and 2 show a Rototiller according to an embodiment of this invention while Figures 3 and 4 show a rotary cultivator obtained by the embodiment.

Referring first to Figures 1 and 2, a cultivator body portion B has an engine unit E installed therein, and is also provided with operating handles 2 each having a handle grip 2a at their rear ends. The body portion B is also provided with a frontguard 26 for protecting the engine unit E against any obstacles lying in front of the unit E in such a manner that the frontguard 26 extends forward and upward so as to cover the front side of the engine unit E.

As shown in Figure 2, a transmission housing 4 is formed integrally with and extends downward vertically from a crank case 3 of the engine E, and a substantially vertical transmission shaft 5 is rotatably supported in the transmission housing 4. The crank case 3 and the transmission housing 4 constitute a transmission case 6 in which a conventional type of transmission gear is housed, and a crank shaft 7 of the engine E is connected to the transmission shaft 5 via the transmission gear. The lower end of the transmission shaft 5 terminates as an integral small driving bevel gear 8 which engages with a large driven bevel gear 10 secured to a cultivator shaft 9 passing horizontally and rotatably through a lower portion of the transmission housing 4. Tiller tines 11 provided with side discs 12 are fixed at both ends of the shaft 9, outside the transmission housing 4.The transmission shaft 5 is driven by the engine E through the transmission gear, and the rotation of the transmission shaft 5 is transmitted to the cultivator shaft 9 by way of the small driving bevel gear 8 and the large driven bevel gear 10, to drive the tiller tines 11. Thus, the transmission shaft 5, the small driving bevel gear 8 and the large driven bevel gear 10 constitute a transmission mechanism T.

Apowertake-offshaft 13which is arranged transversely to the cultivator shaft 9 is borne rotatably through afrontwall 4a ata lower portion ofthe transmission housing 4. The inner end of the power take-off shaft 13 terminates as an integral small driven bevel gear 14 engaging with the large driven bevel gear 10. The outer end of the power take-off shaft 13 projects from the transmission housing 4, and this projecting portion of the shaft 13 is splined.

A cover 15 is removably attached by bolts 16 to the lower front side of the transmission housing 4 so as to enclose the outer end of the power take-off shaft 13.

In the cultivator shown in Figures 1 and 2, when the engine E is operated, the rotation of its crank shaft 7 is transmitted to the cultivator shaft 9 via the transmission mechanism T, making the tiller tines 11 turn with the corresponding side discs 12, to effect rototilling as the cultivator moves. This tilling mechanism is suitable for relatively rough plowing.

In Figures 3 and 4, the cover 15 of the cultivator shown in Figures 1 and 2 is removed and the base end of a running wheel unit U is removably secured in a cantilever fashion by a bolt 17 to the front wall 4a of the lower portion of the transmission housing 4 in which a way as to enclose the projecting end of the power take-off shaft 13. A casing 18 of the wheel unit U consists of a hollow cylindrical portion 18a and a gear case 1 8b formed integrally with the cylindrical portion 18a, at its foremost end. Top opening of the gear case 18b is closed by a cover 19. Within and along the full length of the hollow cylindrical portion 18a, a rotatable interlocking shaft 20 extends with its one end splined around its periphery and located facingly to the corresponding end of the power take-off shaft 13.The adjacent ends of the power take-off shaft 13 and the interlocking shaft 20 are spline-connected together by a hollow connector 21.

At the other end of the interlocking shaft 20, an integral small driving bevel gear 22 is provided for engagement with a large driven bevel gear 23 secured to a wheel axle 24 which is rotatably borne by the gear case 18b and extends therethrough laterally. A pair of running wheels 25 are mounted at both ends of the axle 24. The rotation of the power take-off shaft 13 is transmitted through the connector 21, the interlocking shaft 20, the small driving bevel gear 22, and the large driven bevel gear 23 to the axle 24 so that the axle 24 rotates at a reduced speed, making the pair of running wheels 25 turn accordingly. The connector 21, interlocking shaft 20 and gears 22, 23 constitute an interlocking mechanism I.

In the structure shown in Figures 3 and 4, when the engine E is operated, the pair of tiller tines 11, 11 are driven to turn together with the side discs 12, and at the same time the pair of running wheels 25 are also rotated. Thus, this structure can convert the cultivator as shown in Figures 1 and 2 into a rotary cultivator which is self-propelled by the running wheels 25. This rotary cultivator is suitable for fine plowing since its running speed is regulated by the running wheels 25.

As described above, the cultivator according to this invention has high versatility in that it can easily be converted from a Rototiller into a rotary cultivator, or vice versa, without changing its cultivating mechanism as including the shaft 9 and tines 11, by merely mounting or dismounting a running wheel unit.

In the rotary cultivator of Figure 3 and 4, when the center of gravity of the cultivator body portion B including the engine E and the transmission case 6 is positioned above the line connecting the groundcontact point of each running wheel 25 and the corresponding handle grip 2a, the cultivator body portion B is liable to rock side-wise, disadvantageously increasing the working load on the handles 2 and also lowering the stability of the cultivator.

Figure 5 shows a modified form of the rotary cultivator of Figures 3 and 4, which is designed to overcome this problem. In Figure 5, A indicates the ground-contact point of the running wheels 25, and G the center of gravity of the cultivator body portion B. The wheels 25 are so arranged that their groundcontact point A is positioned forward of the extension a of a line connecting the handle grips 2a and the center of gravity G of the cultivator body portion B, that is to say, the center of gravity G is located below a line b connecting the handle grips 2a and the ground-contact point A of the wheels 25. This arrangement can reduce the sidewise rocking of the body portion B, resuiting in an increased cultivator stability as well as easy and expedited cultivating work.

In this modified form, each running wheel 25 is desinged of a relatively large diameter so as to provide a better running performance, and also the axle 24 of the wheels 25 is rotatably supported on the front end of the casing 18 of the running wheel unit U at a point offset upward so that a desired plowing depth e, for example about 10-15 cm, can be ensured.

Figures 6 and 7 show another modified form of the rotary cultivator of Figures 3 and 4. In this case, the running wheel unit U is specifically mounted on the cultivator body portion B in such a manner that the axle 24 of the running wheels 25 is positioned forward of the front end of the frontguard 26 provided in front of the engine E. A reinforcing bar 27 is also bridged for connection between the front end of the casing 18 of the wheel unit U and a part of the transmission case 6 which forms an upper section of the cultivator body portion B.

In this case, the frontguard 26 is preferably positioned so that it does not project outward from the tangent connecting the engine unit E of the wheels 25. In this modified form, as in the form shown in Figure 5, the axle 24 of the wheels 25 is rotatably supported on the front end of the casing 18 at a point offset upward.

Further, according to this modified form, when it is required to tilt the cultivator forward with the ground-contact point of each wheel 25 acting as fulcrum, for the purpose of changing the direction of travel of the cultivator, it is possible to incline the cultivator forward to a larger extent until the frontguard 26 reaches the vertical tangent extending from the foremost end of the wheels 25, since the axle 24 is positioned forward of the front end of the frontguard 26. Therefore, when for instance, an obstacle 0 such as a mound of earth lies just ahead of the cultivator, an operator can change the direction of travel of the cultivator easily and quickly without the frontguard 26 touching the obstacle 0, and hence with no fear of damaging the mound with the frontguard 26. Further, since the reinforcing bar 27 is provided between the front end of the casing 18 and the transmission case 6, the strength with which the running wheels 25 are supported is augmented by the truss structure constituted by the cultivator body portion B, the casing 18 and the reinforcing bar 27, so that even if the size of the casing 18 is elongated, sufficient support strength is provided.

Claims

1. A cultivator comprising a body portion, an engine mounted in the body portion, a transmission housing extending downward from the engine, a cultivator shaft which extends substantially horizontally and laterally through a lower portion of the transmission housing and on which is mounted a cultivating mechanism including tiller tines, and a transmission mechanism housed in the transmission housing and linking the outut end of the engine to the cultivator shaft so that the cultivating mechanism is driven by the engine, wherein a power take-off shaft linked to the transmission mechanism projects from a lower front portion of the transmission housing.

2. A cultivator as claimed in claim 1 and further comprising a running wheel unit having a pair of running wheels rotatably mounted on lateral sides of a front end thereof, which unit can be removably secured to the lower front portion of the transmission housing, the running wheel unit being provided therein with an interlocking mechanism which interlocks the power take-off shaft with the running wheels, when the unit is secured to the transmission housing.

3. A cultivator as claimed in claim 2, wherein on the cultivator body portion are provided handles extending upward and rearward; and wherein the running wheels when fitted are positioned so that their ground-contact point is located forward of an extension of a line connecting grips of the handles and the center of gravity of the cultivator body portion.

4. A cultivator as claimed in claim 2 or 3, wherein a front-guard is provided so as to cover the front of the engine; and wherein an axle of the running wheels when fitted is positioned forward of the front end of the frontguard.

5. A cultivator substantially as hereinbefore described with reference to Figures 1 and 2, or Figures 3 and 4, or Figures 5, or Figures 6 and 7 of the accompanying drawings.

5. A cultivator as claimed in claim 2,3 or 4, wherein a reinforcing bar is bridged for connection between the front end of a casing for housing the interlocking mechanism of the wheel unit and an upper part of the cultivator body portion.