GB1586730A

GB1586730A - Support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor

Info

Publication number: GB1586730A
Application number: GB11246/78A
Authority: GB
Original assignee: Maskinfabriken Taarup AS
Current assignee: Maskinfabriken Taarup AS
Priority date: 1977-03-24
Filing date: 1978-03-21
Publication date: 1981-03-25
Also published as: IT7821531A0; DK143531C; DK143531B; IT1093603B; DK130077A; FR2384431A1; NL7803121A; ES468176A1; FR2384431B1; DE2811768A1

Description

(54) SUPPORT STRUCTURE FOR SECURING A MOWING BEAM OR OTHER AGRICULTURAL IMPLEMENT TO THE THREE-POINT LINKAGE OF A TRACTOR (71) We, MASKINFABRIKEN TAARUP A/S, a Danish company, of DK-5300 Kerteminde, Denmark, 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 statement:- This invention relates to a support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor.

According to the present invention there is provided a support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor, which support structure comprises a suspension means, the upper part of which is attached to the top link of the tractor, while the suspension means at the lower part thereof is attached to each of the two lower linkages of the tractor, the agricultural implement being swingably mounted in a vertical plane at one end of a transverse swing beam located, seen in the direction of travel, behind the.suspension means, which swing beam at the other end is mounted on a horizontal shaft at the side of the suspension means facing away from the agricultural implement, a balance spring being connected between the suspension means and an arm extending upwardly from the agricultural implement, the point of connection of the balance spring on the upwardly extending arm being disposed eccentrically in relation to the axis of swing of the agricultural implement on the swing beam, and said horizontal shaft being attached to the suspension means and mounted swingably in a horizontal plane around an axis which, seen in the intended direction of operative travel of the tractor, is located behind the swing beam.

By providing that the horizdntal shaft just mentioned is mounted swingably in a horizontal plane around an axis which is located behind the swing beam, there is obtained a support structure in which the agricultural implement automatically swings into its position again.once an obstacle has been passed. This is in contradistinction to previous proposals in which the swing beam mentioned above is attached at either side of the suspension means, this attachment being on the shaft at the side of the suspension means facing away from the agricultural implement, and by means of a security device on the other side of the suspension means. In this arrangement if the agricultural implement hits a stone or other dangerous obstacle, the security device, which comprises angle bent flat-irons kept in mutual engagement by the force of a spring, is released, permitting the swing beam with the implement to swing backwards around a vertical axis through said shaft immediately behind the suspension means. This usually prevents damage to the agricultural implement, but after the passage of the obstacle the security device must be reconnected, which is done by stopping and backing the tractor. In the event that such obstacles too often cause the security means to be released, the spring of the security device may be tightened. Such tightening entails, however, a greater risk of damage to the agricultural implement. It may also occur that the tractor . operator is tempted to weld the security device together so that it does not have the intended effect at all.

In the structure defined above in which the horizontal shaft is mounted swingably in a horizontal plane around an axis which is located behind the swing beam it is made possible to omit completely the security device since the balance spring serves to maintain the agricultural implement in the normal operating position. When the-agricultural implement hits an obstacle it swings backwards revolving together with the swing beam and the shaft of the swing beam around the bearing pin for said shaft behind the swing beam. This result in a further tightening of the balance spring because the swing point, that is to say the bearing pin of the axle pin is located behind the swing beam, while the balance spring is secured to the suspension means in front of the swing beam. As a consequence of the additional tightening of the balance spring, said spring is capable of lifting the implement over the obstacle. When the obstacle has been passed the balance spring will automalically draw the implement into the correct operating position again, and it will, once it has resumed its less tightened state, permit the implement to be relowered so as to contact the ground. The fast swing of the implement when it hits even a small obstacle and the automatic backswing once the obstacle has been passed entail that the implement is subjected to considerably smaller impacts than previously, resulting in smaller strength requirements of the implement and its support structure, and the weight thereof can therefore be reduced.

This again is of great importance because the tractor can be used with a longer agricultural implement giving a greater effect.

This also makes it easier to secure the suspension means to the tractor, because the suspension means at the lower end of the side facing away from said horizontal shaft can at a slight impact be moved forwards and downwards to be connected to the lift and draw bar of the tractor, while the swing beam and the agricultural impleinent still contact on the ground.

In a preferred embodiment the swing beam at the side thereof facing the suspension means is provided with an engagement member which when the swing beam is in its front, normal operating position, is projecting between two stop means attached to the suspension means, which stop means are adapted to limit the swinging movement of the swing beam around the horizontal shaft.

Hereby it is achieved that under normal dperation the agricultural implement follows the ground without unnecessarily large swings in the vertical plane. When, on the other hand, the implement hits an obstacle the engagement member is disengaged from the two stop means, and the implement can swing freely over the obstacle.

The invention will be described in more detail below by way of example with reference to the accompanying drawing showing in perspective a support structure.

The support structure shown on the drawing comprises a suspension means 1 in the form of a downwardly facing U. At the upper part the suspension means 1 is secured to a toplink 2 attached to a tractor not shown, while the suspension means at the lower part thereof is secured to each of the two linkages of the tractor 3 and 4 respectively. The suspension means 1 is thus secured behind the tractor transversely to the direction of travel.

A backwardly extending bracket arm 5, which is attached to the suspension means 1 in the same side as the linkage 3, constitutes the support of a horizontal shaft 6 mounted swingably in a horizontal plane around a vertical pin 7 fitted in the rearmost end of the bracket arm 5. The front end of the bracket arm 5 constitutes the journal of one end of a swing beam 8 in whose other end an agricultural implement 9, for example a mowing beam, is mounted swingably in a vertical plane. An upwardly extending arm 10 is swingably mounted on the agricultural implement 9 adjacent the bearing 13 for said implement in the swing beam 8. By means of a pull spring 11, which serves as a balance spring, the arm 10 is connected to a support 12 of the upper part of the suspension means 1.

The arm 10 can rotate freely clockwise when the implement 9 is swung around its bearing 13 in the swing beam 8 to a vertical position as is necessary during driving on a road. On the implement 9, on the other hand, the bearing 13 serves as a stop which limits the counter-clockwise rotation of the arm 10 from the position shown on the drawing.

At normal operation of the tractor the implement follows the ground with an insignificant contact pressure, the greater part of the weight of the implement 9 and the swing beam 8 being counterbalaced by the pulling force of the balance spring 11.

When the agricultural implement 9 hits a stone or another obstacle it swings together with the swing beam 8 and the horizontal shaft 6 backwards around the pin 7, resulting in a tensioning of the balance spring 11 so that the pressure of the implement 9 against the ground and the obstacle is reduced, and its passage over the obstacle is facilitated. This is the position which is shown on the drawing.

Once the obstacle has been passed the implement 9, the swing beam 8 and the shaft 6 swing into their positions. Two bars 14 serve to limit the elongation of the spring 11 when an obstacle is encountered.

An engagement member 15 is attached to the side of the swing beam facing the suspension means, which member when the swing beam 8 is in its front, normal operating position, is in projecting between two stop means 16 and 17 secured to the suspension means 1.

WHAT WE CLAIM IS: 1. A support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor, which support structure comprises a suspension means, the upper part of which is attached to the toplink of the tractor, while the suspension means at the lower part thereof is attached to each of the two lower linkages of the tractor, the agricultural

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the additional tightening of the balance spring, said spring is capable of lifting the implement over the obstacle. When the obstacle has been passed the balance spring will automalically draw the implement into the correct operating position again, and it will, once it has resumed its less tightened state, permit the implement to be relowered so as to contact the ground. The fast swing of the implement when it hits even a small obstacle and the automatic backswing once the obstacle has been passed entail that the implement is subjected to considerably smaller impacts than previously, resulting in smaller strength requirements of the implement and its support structure, and the weight thereof can therefore be reduced. This again is of great importance because the tractor can be used with a longer agricultural implement giving a greater effect. This also makes it easier to secure the suspension means to the tractor, because the suspension means at the lower end of the side facing away from said horizontal shaft can at a slight impact be moved forwards and downwards to be connected to the lift and draw bar of the tractor, while the swing beam and the agricultural impleinent still contact on the ground. In a preferred embodiment the swing beam at the side thereof facing the suspension means is provided with an engagement member which when the swing beam is in its front, normal operating position, is projecting between two stop means attached to the suspension means, which stop means are adapted to limit the swinging movement of the swing beam around the horizontal shaft. Hereby it is achieved that under normal dperation the agricultural implement follows the ground without unnecessarily large swings in the vertical plane. When, on the other hand, the implement hits an obstacle the engagement member is disengaged from the two stop means, and the implement can swing freely over the obstacle. The invention will be described in more detail below by way of example with reference to the accompanying drawing showing in perspective a support structure. The support structure shown on the drawing comprises a suspension means 1 in the form of a downwardly facing U. At the upper part the suspension means 1 is secured to a toplink 2 attached to a tractor not shown, while the suspension means at the lower part thereof is secured to each of the two linkages of the tractor 3 and 4 respectively. The suspension means 1 is thus secured behind the tractor transversely to the direction of travel. A backwardly extending bracket arm 5, which is attached to the suspension means 1 in the same side as the linkage 3, constitutes the support of a horizontal shaft 6 mounted swingably in a horizontal plane around a vertical pin 7 fitted in the rearmost end of the bracket arm 5. The front end of the bracket arm 5 constitutes the journal of one end of a swing beam 8 in whose other end an agricultural implement 9, for example a mowing beam, is mounted swingably in a vertical plane. An upwardly extending arm 10 is swingably mounted on the agricultural implement 9 adjacent the bearing 13 for said implement in the swing beam 8. By means of a pull spring 11, which serves as a balance spring, the arm 10 is connected to a support 12 of the upper part of the suspension means 1. The arm 10 can rotate freely clockwise when the implement 9 is swung around its bearing 13 in the swing beam 8 to a vertical position as is necessary during driving on a road. On the implement 9, on the other hand, the bearing 13 serves as a stop which limits the counter-clockwise rotation of the arm 10 from the position shown on the drawing. At normal operation of the tractor the implement follows the ground with an insignificant contact pressure, the greater part of the weight of the implement 9 and the swing beam 8 being counterbalaced by the pulling force of the balance spring 11. When the agricultural implement 9 hits a stone or another obstacle it swings together with the swing beam 8 and the horizontal shaft 6 backwards around the pin 7, resulting in a tensioning of the balance spring 11 so that the pressure of the implement 9 against the ground and the obstacle is reduced, and its passage over the obstacle is facilitated. This is the position which is shown on the drawing. Once the obstacle has been passed the implement 9, the swing beam 8 and the shaft 6 swing into their positions. Two bars 14 serve to limit the elongation of the spring 11 when an obstacle is encountered. An engagement member 15 is attached to the side of the swing beam facing the suspension means, which member when the swing beam 8 is in its front, normal operating position, is in projecting between two stop means 16 and 17 secured to the suspension means 1. WHAT WE CLAIM IS:

1. A support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor, which support structure comprises a suspension means, the upper part of which is attached to the toplink of the tractor, while the suspension means at the lower part thereof is attached to each of the two lower linkages of the tractor, the agricultural

implement being swingably mounted in a vertical plane at one end of a transverse swing beam located, seen in the direction of travel, behind the suspension means, which swing beam at the other end is mounted on a horizontal shaft at the side of the suspension means facing away from the agricultural implement, a balance spring being connected between the suspension means and an arm extending upwardly from the agricultural implement, the point of connection of the balance spring on the upwardly extending arm being disposed eccentrically in relation to the axis of swing of the agricultural implement on the swing beam, and said horizontal shaft being attached to the suspension means and mounted swingably in a horizontal plane around an axis which, seen in the intended direction of operative travel, of the tractor is located behind the swing beam.

2. A support structure according to claim 1, wherein the swing beam at the side thereof facing the suspension means is provided with an engagement member which when the swing beam is in its front, normal operating position, projects between two stop means attached to the suspension means, which stop means are adapted to limit the swinging movement of the swing beam around the horizontal shaft.

3. A support structure for securing a mowing beam or other agricultural implement to the three-point linkage of a tractor, substantially as hereinbefore described with reference to the accompanying drawing.