GB1562695A

GB1562695A - Link mechanism for connecting an agricultural attachment apparatus to a tractor

Info

Publication number: GB1562695A
Application number: GB4833776A
Authority: GB
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 1976-02-10
Filing date: 1976-11-19
Publication date: 1980-03-12
Also published as: FR2340674B1; DE2658244C3; FR2340674A1; DE2658244B2; CA1098758A; DE2658244A1

Description

(54) IMPROVEMENTS IN OR RELATING TO A LINK MECHANISM FOR CONNECTING AN AGRICULTURAL ATTACHMENT APPARATUS TO A TRACTOR (71) We, KUBOTA, LTD., of 22-banchi, 2-chome, Funade-cho, Naniwa-ku, Osakashi, 556 Japan; a joint stock company existing under the laws of Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment: - The present invention relates to a link mechanism for attaching an agricultural apparatus, such as a vertically displaceable rotary plough assembly attached to a tractor or like towing vehicle. An arrangement is incorporated wherein power transmission is effected from an output shaft on the tractor frame to an input shaft on the plough assembly by way of a rotary transmission shaft with universal joints disposed at both ends thereof.

For moving the rotary plough assembly up and down relative to the tractor frame by means of the link mechanism, a known link mechanism has been in a substantially parallel quadrilateral form effective to move the plough assembly substantially parallel to the tractor frame.

This known arrangement is intended for maintaining the output shaft on the tractor frame and the input shaft on the plough assembly which are operatively interlocked with two universal joints substantially parallel at all times irrespective of the position of the plough assembly. That is, in connecting the shafts by means of two universal joints, the rotating rate of the output shaft can be transferred unchangedly to the input shaft, and vibrations and noise can be kept down by substantially uniformalizing the crossing angles between each of the output and input shafts and the transmission shaft to render the output and input shafts substantially parallel. It is with this functional advantage in view that the plough assembly has been raised and lowered with the substantially parallel quadrilateral link mechanism.

However, as illustrated in Fig. 4 of the accompanying drawings, it is impossible to raise plough assembly 1 very high above the ground to bring it to an idle position with parallel quadrilateral link mechanism 7'. This is inconvenient in turning the tractor to reverse the ploughing directions near ridges or driving it over ridges.

It is an object of the invention to provide a link mechanism for connecting a plough with a tractor whereby the plough assembly may be raised to a considerable height when the latter is idle, while exhibiting advantages in the associated action of the output and input shapes.

It is an object of this invention to provide a tractor-plough link mechanism capable of effecting smooth power transmission to the plough assembly and of raising the plough assembly high above the ground at the time of reversing and the like.

Another object of this invention is to provide a tractor-plough link mechanism enabling the plough assembly to be mounted at the rear end thereof in a reliable manner with a simple arrangement.

According to the present invention there is provided a link mechanism for pivotally connecting an agricultural attachment apparatus such as a plough assembly to the rear end of a tractor, comprising two lower links pivotally connectable at one end to the tractor, capable of being raised and lowered and being disposed generally horizontal during operation, an upper short link pivotally connected at one end to the free end of a bracket securable to the tractor with said bracket being longer than said upper link, and wherein further link means is pivotally connected at one end to the other free end of said upper link and is longer than the upper link and joinable to the attachment apparatus at its other free end, said further link means joined to the upper link is also attached, via connecting link means, to a pivot point at the other free end of the lower link and to the attachment apparatus, the other end of the connecting link being pivotally connected near the pivot point between the upper link and further link.

By so arranging that the upper and lower links of the link mechanism are substantially parallel and the output and input shafts are substantially parallel when the plough assembly is near the ground engaging position, the plough assembly is allowed to move up and down within the operative compass without substantial alterations to such parallel states.

That is to say, while in the operative compass, the plough assembly can move up and down without affecting the interlocking function of the universal joints. And, by making the upper link shorter than the lower links, with this interlocking function at full play, the plough assembly can be raised to a very high inoperative position for the extent of link oscillation. Thus, during ploughing work, the input shaft is driven at the same rate as the output shaft to produce very little vibrations and noise, and yet, to the great advantage of the tractor, the plough assembly can be raised high at the time of reversing the tractor or driving it over ridges.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view of the rear portion of a tractor together with link mechanism and plough; Figs. 2 and 3 are views illustrating a plough assembly at lowered and raised posidons, re spectively;' Fig. 4 is a view corresponding to Fig. 3 and illustrating the conventional plough assembly at a raised position; Fig. 5 is a part view in vertical section showing the portion of the tractor mounting the plough assembly; Fig. 6 is a partly broken away perspective view showing the same portion as in Fig. 5; Fig. 7 is a rear view in cross section showing another embodiment of the invention; and Fig. 8 is a side view in vertical section showing the known plough assembly mounting portion.

In Fig. 1, a rotary plough assembly 1 is shown attached to the rear end of a tractor frame 2. An interlocking mechanism 5 includes a transmission shaft 9 which forms the connection between output shaft 4 protruding from a transmission case 3, and an input shaft 6 of plough assembly 1.

Transmission shaft 9 is joined to a tubular cover 10 and universal joints 11, which are supported by the ends of tubular cover 10.

Link mechanism 7 consists of two lower long links 12 pivotally connected at P3 to a lower portion of transmission case 3 and at P4 to the frame of the plough assembly 1 and also of an upper link 14 which is pivotally connected at P1 to the rear free end of a bracket 13 which is secured to the rear end of a tractor. Lift arms 8 are pivotally connected to lower links 12. Lower links 12 are considerably longer than upper link 14. A further link 14' is pivotally connected to the free end P2 of the upper link 14,this is longer than upper link 14 and is joined to the frame of the plough assembly 1 at its free end.

Furthermore, link 14', which is attached to upper link 14, is joined to pivot point P4 of the free end of the lower link 12 and to the plough assembly 1 via a connection link 14", the other end of which link 14" is pivotally connected near to pivot point P2 of the two above mentioned links 14 and 14'. As the angle between the link 14' and link 14" does not alter, production can be simplified by replacing these with any equivalent means containing openings for the pivot points. With regard to a specific ratio between the distances between upper link 14 and lower links 12, the experiments conducted have produced the following desired effect: the length of upper link 14, i.e.

the distance between pivots P1 and P2 125 mm the length of each lower link 12 i.e. the distance between pivots P3 and P4 550 mm the distance between pivots P1 and P3 353 mm the distance between pivots P2 and P4 342 mm In Fig. 2, links 12 and 14 are arranged substantially parallel to each other when the plough assembly is in the middle of its ground engaging compass (ploughing compass). Output shaft 4 and input shaft 6 are also arranged substantially parallel to each other at this position. The plough assembly is therefore movable substantially parallel to itself within the ground engaging compass.

As is illustrated in Fig. 3, when the plough assembly is raised from the ground engaging position to the transport position, lift arm 8 lifts lower links 12 and causes them to turn on pivot P3 on the tractor frame 2, which in turn raises plough assembly 1 and causes it to turn on pivot 4 at the same time. Output shaft 4, transmission shaft 9 and input shaft 6 are positioned in such a way that, when the plough assembly 1 is at its highest position, substantially the same angle M is set between the output shaft 4 and the transmission shaft 9, and between the transmission shaft 9 and input shaft 6.

In this position plough assembly 1 can still be actuated so that ploughing can be resumed immediately the tractor has been turned round and the plough assembly re-lowered.

How plough assembly 1 is attached to tractor frame 2 will now be described. As seen from Figs. 5 and 6, a channel-shaped mounting member 16 is attached to the rear end of trator frame 2, and bracket 13 is removably mounted on mounting member 16, bracket 13 pivotally supporting one end of short link 14 to allow the latter to oscillate on pivot P1.

Mounting member 16 has four perforations 17, and bracket 13 also has four perforations 18, perforations 17 and 18 having a larger diameter than a connecting rod 19 to receive connecting rod 19 therethrough. Numeral 20 indicates a hand lever having a perforation 21 slightly larger in diameter than rod 19, and a wedge member 22 connected thereto by pivot P.

In assembling bracket 13 and mounting member 16, lever 20 is first placed in bracket 13, and the two are then fitted into mounting member 16 placing perforations 17, 18, and 21 of the three elements in alignment, and finally connecting rod 19 is fitted to extend loosely therethrough. Next, lever 20 is turned in the direction indicated by the arrow to cause wedge member 22 to move into space between back wall 23 of mounting member 16 and a plate 24 on bracket 13, whereby bracket 13 is pushed toward plough 1 relative to mounting member 16 so as to prevent clattering of connecting rod 19 in perforations 17, 18.

Advantages of the above mounting arrangement will now be discussed in detail in comparison with the known arrangement. Generally, in connecting bracket 13 and plough assembly 1 to the rear end of tractor frame 2 using connecting rod 19, perforations 17, 18 are formed diametrically larger than rod 19 to easily receive the latter, and a wedge member is used to prevent clattering of rod 19 in perforations 17, 18. As shown in Fig. 8, according to the known art, a pair of wedge members 22' are urged toward each other with a spring 25 to interpose between back wall 23 of channel-shaped mounting member 16 and plate 24 of bracket 13. However, in such arrangement, two wedge members 22' have to be pulled apart against expansion spring 25 at the time of fitting rod 19 in order to bring perforations 17, 18 substantially into alignment. If this is done manually, spring 25 must be resilient enough to manage with human power, which reduces its effect of preventing clattering of rod 19 in perforations 17, 18.

It may be conceived to use a gearing device to pull apart wedge members 22' for easy manual operation in spite of a big drawing force of the spring, but this will require complicated construction and operation.

According to the arrangement of this in vendon, hand lever 20 is provided pivotably on connecting rod 19 extending through channel-shaped mounting member 16 and bracket 13 on frame 2, and in association with this lever 20 by such as a pin is provided wedge member 22 to wedge between mounting member 16 and bracket 13. Connecting rod 19, which is a necessary constituent member, is used to support wedge member 22, hence little chance of losing wedge member 22. Since pivotal movement of lever 20 about the axis of rod 19 causes wedge member 22 to wedge between mounting member 16 and bracket 13, a strong wedging can be obtained with a relatively weak actuating force using a lever of suitable length.

Accordingly, the use of a necessary constituent element, namely rod 19, for sustaining wedge member 22 is an advantage in that the construction is simple, there is little chance of losing wedge member 22, and that wedge member 22 can be driven in powerfully and yet easily.

Instead of pivotally mounting hand lever 20 direct on connecting rod 19, bracket 13 may carry a pipe 26 secured thereto to receive rod 19, and lever 20 be mounted on pipe 26, as shown in Fig. 7. Such arrangement provides for even easier mounting of connecting rod 19 and renders a less chance of losing wedge member 22.

WHAT WE CLAIM IS: 1. A link mechanism for pivotally connecting an agricultural attachment apparatus such as a plough assembly to the rear end of a tractor, comprising two lower links pivotally connectable at one end to the tractor, capable of being raised and lowered and being disposed generally horizontally during operation, an upper short link pivotally connected at one end to the free end of a bracket securable to the tractor with said bracket being longer than said upper link, and wherein further link means is pivotally connected at one end to the other free end of said upper link and is longer than the upper link and joinable to the attachment apparatus at its other free end, said further link means joined to the upper link is also attached, via connecting link means, to a pivot point at the other free end of the lower link and to the attachment apparatus, the other end of the connecting link means being pivotally connected near the pivot point between the upper link and further link.

2. A link mechanism as claimed in claim 1 further comprising; a channel-shaped mounting member adapted to be secured to the rear end of the tractor frame, a bracket removably mounted on the mounting member to pivotally engage one end of the short link, a connecting rod adapted to extend through perforations defined on the mounting member and the bracket and being slightly smaller in diameter than perforation, a hand lever pivotable on the connecting rod, and a wedge member operatively connected

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tractor frame 2 will now be described. As seen from Figs. 5 and 6, a channel-shaped mounting member 16 is attached to the rear end of trator frame 2, and bracket 13 is removably mounted on mounting member 16, bracket 13 pivotally supporting one end of short link 14 to allow the latter to oscillate on pivot P1. Mounting member 16 has four perforations 17, and bracket 13 also has four perforations 18, perforations 17 and 18 having a larger diameter than a connecting rod 19 to receive connecting rod 19 therethrough. Numeral 20 indicates a hand lever having a perforation 21 slightly larger in diameter than rod 19, and a wedge member 22 connected thereto by pivot P. In assembling bracket 13 and mounting member 16, lever 20 is first placed in bracket 13, and the two are then fitted into mounting member 16 placing perforations 17, 18, and 21 of the three elements in alignment, and finally connecting rod 19 is fitted to extend loosely therethrough. Next, lever 20 is turned in the direction indicated by the arrow to cause wedge member 22 to move into space between back wall 23 of mounting member 16 and a plate 24 on bracket 13, whereby bracket 13 is pushed toward plough 1 relative to mounting member 16 so as to prevent clattering of connecting rod 19 in perforations 17, 18. Advantages of the above mounting arrangement will now be discussed in detail in comparison with the known arrangement. Generally, in connecting bracket 13 and plough assembly 1 to the rear end of tractor frame 2 using connecting rod 19, perforations 17, 18 are formed diametrically larger than rod 19 to easily receive the latter, and a wedge member is used to prevent clattering of rod 19 in perforations 17, 18. As shown in Fig. 8, according to the known art, a pair of wedge members 22' are urged toward each other with a spring 25 to interpose between back wall 23 of channel-shaped mounting member 16 and plate 24 of bracket 13. However, in such arrangement, two wedge members 22' have to be pulled apart against expansion spring 25 at the time of fitting rod 19 in order to bring perforations 17, 18 substantially into alignment. If this is done manually, spring 25 must be resilient enough to manage with human power, which reduces its effect of preventing clattering of rod 19 in perforations 17, 18. It may be conceived to use a gearing device to pull apart wedge members 22' for easy manual operation in spite of a big drawing force of the spring, but this will require complicated construction and operation. According to the arrangement of this in vendon, hand lever 20 is provided pivotably on connecting rod 19 extending through channel-shaped mounting member 16 and bracket 13 on frame 2, and in association with this lever 20 by such as a pin is provided wedge member 22 to wedge between mounting member 16 and bracket 13. Connecting rod 19, which is a necessary constituent member, is used to support wedge member 22, hence little chance of losing wedge member 22. Since pivotal movement of lever 20 about the axis of rod 19 causes wedge member 22 to wedge between mounting member 16 and bracket 13, a strong wedging can be obtained with a relatively weak actuating force using a lever of suitable length. Accordingly, the use of a necessary constituent element, namely rod 19, for sustaining wedge member 22 is an advantage in that the construction is simple, there is little chance of losing wedge member 22, and that wedge member 22 can be driven in powerfully and yet easily. Instead of pivotally mounting hand lever 20 direct on connecting rod 19, bracket 13 may carry a pipe 26 secured thereto to receive rod 19, and lever 20 be mounted on pipe 26, as shown in Fig. 7. Such arrangement provides for even easier mounting of connecting rod 19 and renders a less chance of losing wedge member 22. WHAT WE CLAIM IS:

1. A link mechanism for pivotally connecting an agricultural attachment apparatus such as a plough assembly to the rear end of a tractor, comprising two lower links pivotally connectable at one end to the tractor, capable of being raised and lowered and being disposed generally horizontally during operation, an upper short link pivotally connected at one end to the free end of a bracket securable to the tractor with said bracket being longer than said upper link, and wherein further link means is pivotally connected at one end to the other free end of said upper link and is longer than the upper link and joinable to the attachment apparatus at its other free end, said further link means joined to the upper link is also attached, via connecting link means, to a pivot point at the other free end of the lower link and to the attachment apparatus, the other end of the connecting link means being pivotally connected near the pivot point between the upper link and further link.

to the hand lever and adapted to advance between a back wall of the mounting member and a plate provided on the bracket with pivotal movement of the hand lever to thereby fix the bracket securely to the mounting member.

3. A link mechanism as claimed in claim 2 further comprising a pipe member secured to the bracket to receive the connecting rod therethrough and to carry the hand lever pivotably fitted thereon.

4. A link mechanism as claimed in any of claims 1 to 3, whenever in combination with an agricultural attachment apparatus.

5. A link mechanism substantially as herein described with reference to and as illustrated in Figs. 1 to 3 and Figs. 1 to 3 and Figs. 5 and 6 or 7 of the accompanying drawings.