GB1563457A - Means for connecting implements to tractors - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO MEANS FOR CONNECTING IMPLEMENTS TO TRACTORS (71) We, OY FISKARS AB., of Man nerheimintie 14 A, 00100 Helsinki 10, Finland, a Finnish joint stock Company, 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 : The present invention relates to a coupling means for connecting an implement to a tractor.

It is known to provide quick connection coupling means for connecting an implement to a tractor in which the body member of the coupling means has a groove for the reception of a draw pin mounted on the implement and in which a locking latch is used to prevent the draw pin falling out of the groove during use. For example, it is known to provide such a coupling means in which the draw pins are fitted to push guide latches in such a way that the guide latches release a locking latch during pivotal movement, whereby a spring pushes the interlocking latch into a locking position above the draw pin in the groove of the coupling means.

There are unfortunately several disadvantages with such an arrangement. To disconnect the implement, the locking latches have to be pulled out of the locking position and unfortunately will not remain automatically in this unlocked position but require that the operator continue to physically keep the locking latches disengaged.

Further, the draw pins during the disconnection operation still impinge against the guide latches. Additionally, the actual connection operation is not entirely satisfactory since it is not sufficient that the draw pins engage the groove in the coupling means but the draw pins must also press sufficiently hard against the guide latches to release the locking latches into the locking position.

It is also proposed that a simple locking latch be provided for the grooves of such coupling means, which locking latch comprises a triangular-shaped plate which is biased to lie across the draw pin when in the groove. However, during the disconnection operation the locking latch must be manually pulled into the unlocked position, and this, while being a relatively simple form of coupling means, is cumbersome and difficult to operate in practice.

To overcome this, there have been used arrangements whereby the locking latches can be maintained in the unlocked position.

In this case, after the implement has been disconnected, the locking latches must be manually moved into the locking position after an implement has been connected.

The objection to this latter form of coupling is that, if due to operator error, this is not done then there is a possibility of an accident since an implement may be disconnected during use or transportation.

According to the invention there is provided a coupling means for connecting an implement to a tractor comprising: a body member. having an open-mouthed groove for reception of a draw pin, mounted on the implement; a locking latch pivotally mounted above the groove for movement into and out of a forward locking position across the draw pin when in the groove, spring means on the body member for urging the locking latch forwards into the locking position; an operating means for withdrawing the locking latch from the locking position, said means including a transverse pin slidable against an edge of a cut-out portion of the locking latch; and a guide latch pivotally mounted above the groove and arranged to engage the draw pin on entering the groove and to pivot rearwardly of the groove to lie against the draw pin when in the groove, the guide latch having a bearing surface for engagement with the transverse pin, whereby, on insertion of a draw pin, the said surface and the edge of the cut-out portion in the locking latch form a guide slot for the pin, the guide slot having a pocket adjacent its upper end, whereby for withdrawal of the locking latch the pin engages the pocket and is retained in it by the draw pin forcing the guide latch rearwardly of the groove and the spring urging the locking latch in the other direction and whereby removal of the draw pin from the groove allows the guide latch to pivot forward to release the pin out of the pocket and hence allow the locking latch to move forward into the locking position.

A preferred coupling or connection means is structurally simple and can be connected quickly. Disconnection can be carried out simply but at the same time ensuring that after disconnection, the locking latch returns automatically to a position such that, when a further implement has to be connected, the locking latch would automatically move into the locking position.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a vertical section of a preferred coupling means before connection of an implement; Figure 2 is a view similar to Figure 1 showing the coupling means with a draw pin connected in the locked position; Figure 3 is a view similar to Figure 2 showing the coupling means with the draw pin in the unlocked position ready for disconnection; and Figure 4 is a partial rear view of the coupling means.

Referring to the drawings, the coupling means include a body member indicated generally by the reference numeral 1. The body member 1 comprises a transverse arm 2 manufactured from a mild steel box section on which is mounted two pairs of plates 3 spaced apart (note only one pair is illustrated in Figure 4). Each plate 3 is provided with an open-mouthed groove 4 for reception of a draw pin 5 of an implement (not shown). The plates 3 are connected together by further support plates 6 and 7. A locking latch 8 is pivotally mounted by a pin 9, defining a pivot axis between the plates 3. Two cranked bars 10 project from the rear of the locking latch 8 to form a cut-out portion 11 which engages a pin 12 mounted transversely on one end of a handle 13. The pin 12 and handle 13 together form an operating means for withdrawing the locking latch 8 as will be described below.

The cutout portion 11 provides a bearing surface 14 for the pin 12. A spring 15 is connected between the locking latch 8 and the plate 6.

A pair of guide latches 20 are mounted between the plates 3 and the locking latch 8 bv a pivot pin 21 defining a pivot axis.

Each guide latch 20 is formed from a flat plate and is of substantially triangular shape having a relatively short base line with its apex depending from its pivot axis which is adjacent one of the base angles.

The guide latch 20 forms a bearing surface 22 for engagement with the pin 12 and has a pocket 23 adjacent its upper end.

In use, the bearing surfaces 22 and the edge 14 of the cut out portion 11 form a guide slot for the pin 12. The guide latch 20 is provided with a cutout portion 24 to accommodate the pin 9.

Each plate 3 is provided with three holes 25 which are substantially vertically aligned for the attachment to the three point linkage of a tractor. It will be noted that the lowermost hole 25 is substantially aligned with the draw pin 5.

Two spaced apart plates 30 are mounted on the transverse arm 2 and support a hook 31. The plates 30 are provided with holes 32 for attachment to the push arm of a tractor. It will be noted that the holes 32 are substantially vertically aligned.

In use, to connect an implement to a tractor to which the coupling means has been fitted the push arm of the tractor is used to offer up the hook 31 to the upper draw pin of the implement. It will be noted that the hook 31 is of relatively wide configuration and accordingly the draw pin is not rigidly secured within the hook 31 but can move relative to it. The coupling means is then offered up to the draw pin 5 and is initially in the position illustrated in Figure 1. The insertion of the draw pin 5 is carried out by raising the coupling means. The draw pin 5 impinges against the guide latch 20 and locking latch 8 as the coupling means is lifted. It will be appreciated that the spring 15 is operating against the movement of the draw pin 5 and accordingly, immediately the draw pin 5 falls below the locking latch 8, the locking latch 8 pivots to the position shown in Figure 2 while simultaneously the guide latch 20 is being pushed rearwardly. When the draw pin 5 is fully connected the guide latch 20 is held by it in the position shown in Figure 2 which is thus the working position.

When it is desired to disconnect the coupling means the handle 13 of the operating means is used, that is to say the handle 13 is pulled and the locking latch 8 is pivoted rearwardly against the spring 15. The pin 12 bears against the bearing surface 22 and will enter the pocket 23. If the handle 13 is now released the spring 15 will maintain the pin 12 in the pocket 23. The locking latch 8 is now disengaged.

The implement is then lowered onto the ground. The draw pin 5 disengages from the open mouthed groove 4 as the coupling means is lowered further. As the draw pin $ moves out of the groove 4 the locking latches 20 pivot. under gravitv until the pocket 23 disengages from the pin 12 when the locking latch can then pivot back into the position illustrated in Figure 1. When the draw pin is completely out of the groove 4 the guide latch 20 takes up its original position. The coupling means is now ready for re-engagement with an implement.

WHAT WE CLAIM IS:- 1. A coupling means for connecting an implement to a tractor comprising: a body member, having an open-mouthed groove for reception of a draw pin, mounted on the implement; a locking latch pivotally mounted above the groove for movement into and out of a forward locking position across the draw pin when in the groove; spring means on the body member for urging the locking latch forwards into the locking position; and operating means for withdrawing the locking latch from the locking position, said means including a transverse pin slidable against an edge of a cutout portion of the locking latch; and a guide latch pivotally mounted above the groove and arranged to engage the draw pin on entering the groove and to pivot rearwardly of the groove to lie against the draw pin when in the groove, the guide latch having a bearing surface for engagement with the transverse pin, whereby, on insertion of a draw pin, the said surface and the edge of the cut-out portion in the locking latch form a guide slot for the pin, the guide slot having a pocket adjacent its upper end, whereby for withdrawal of the locking latch the pin engages the pocket and is retained in it by the draw pin forcing the guiide latch rearwardly of the groove and the spring urging the locking latch in the other direction and whereby removal of the draw pin from the groove allows the guide latch to pivot forward to release the pin out of the pocket and hence allow the locking latch to move forward into the locking position.

2. A coupling means as claimed in claim 1, in which the pivot axes of the locking latch and guide latch are substantially vertically aligned and spaced a short distance apart.

3. A coupling means as claimed in any preceding claim, in which the guide latch is biased by its own weight into a position forward of the groove.

4. A coupling means as claimed in any preceding claim, in which the guide latch is of substantially triangular shape in vertical section having a relatively short base line, its apex depending from its pivot axis which is adjacent one of its base angles.

5. A coupling means as claimed in any preceding claim, in which the body member includes a pair of parallel spaced apart plates, the locking latch being mounted between the plates, and in which two guide latches are provided, each guide latch being formed from a flat plate, pivotally mounted between the locking latch and one of the plates forming the body member.

6. A coupling means as claimed in any preceding claim, in which the body member has vertically aligned holes for attachment to the three point linkage of a tractor, the lowermost hole, in use, aligning horizontally with the draw pin.

7. A coupling means as claimed in any preceding claim, in which the body member incorporates a hook for reception of an upper draw pin on the implement and in which vertically aligned holes are provided in the body member for attachment to the push arm of the tractor.

8. A coupling means substantially as described herein with reference to and as illustrated in the accompanying drawings.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. the locking latch can then pivot back into the position illustrated in Figure 1. When the draw pin is completely out of the groove 4 the guide latch 20 takes up its original position. The coupling means is now ready for re-engagement with an implement. WHAT WE CLAIM IS:-

1. A coupling means for connecting an implement to a tractor comprising: a body member, having an open-mouthed groove for reception of a draw pin, mounted on the implement; a locking latch pivotally mounted above the groove for movement into and out of a forward locking position across the draw pin when in the groove; spring means on the body member for urging the locking latch forwards into the locking position; and operating means for withdrawing the locking latch from the locking position, said means including a transverse pin slidable against an edge of a cutout portion of the locking latch; and a guide latch pivotally mounted above the groove and arranged to engage the draw pin on entering the groove and to pivot rearwardly of the groove to lie against the draw pin when in the groove, the guide latch having a bearing surface for engagement with the transverse pin, whereby, on insertion of a draw pin, the said surface and the edge of the cut-out portion in the locking latch form a guide slot for the pin, the guide slot having a pocket adjacent its upper end, whereby for withdrawal of the locking latch the pin engages the pocket and is retained in it by the draw pin forcing the guiide latch rearwardly of the groove and the spring urging the locking latch in the other direction and whereby removal of the draw pin from the groove allows the guide latch to pivot forward to release the pin out of the pocket and hence allow the locking latch to move forward into the locking position.

2. A coupling means as claimed in claim 1, in which the pivot axes of the locking latch and guide latch are substantially vertically aligned and spaced a short distance apart.

3. A coupling means as claimed in any preceding claim, in which the guide latch is biased by its own weight into a position forward of the groove.

4. A coupling means as claimed in any preceding claim, in which the guide latch is of substantially triangular shape in vertical section having a relatively short base line, its apex depending from its pivot axis which is adjacent one of its base angles.

5. A coupling means as claimed in any preceding claim, in which the body member includes a pair of parallel spaced apart plates, the locking latch being mounted between the plates, and in which two guide latches are provided, each guide latch being formed from a flat plate, pivotally mounted between the locking latch and one of the plates forming the body member.

6. A coupling means as claimed in any preceding claim, in which the body member has vertically aligned holes for attachment to the three point linkage of a tractor, the lowermost hole, in use, aligning horizontally with the draw pin.

7. A coupling means as claimed in any preceding claim, in which the body member incorporates a hook for reception of an upper draw pin on the implement and in which vertically aligned holes are provided in the body member for attachment to the push arm of the tractor.

8. A coupling means substantially as described herein with reference to and as illustrated in the accompanying drawings.