GB2040664A

GB2040664A - Coupling implements to tractors

Info

Publication number: GB2040664A
Application number: GB7903855A
Authority: GB
Original assignee: Ferranti PLC
Current assignee: Ferranti International PLC
Priority date: 1979-02-03
Filing date: 1979-02-03
Publication date: 1980-09-03
Also published as: GB2040664B

Abstract

Apparatus for coupling an agricultural implement to a tractor includes a first coupling member for attachment to the implement and in the form of an inverted-Vee (10) of channel-shaped cross-section. A second coupling member (16) of similar shape is attached to the tractor, and carries hook-shaped latching means 21 for engagement with a part 14 of the first coupling member (10). The second coupling member (16) also carries locking means arranged to prevent the operation of the latching means and comprising a spring-loaded bolt 26 having two operating positions in one of which the bolts 26 enters a hole in the hook-shaped latching means 21 to prevent its operation. <IMAGE>

Description

SPECIFICATION Coupling apparatus for agricultural implements This invention relates to coupling apparatus for agricultural implements, and in particular to apparatus for detachably coupling an agricultural implement to a tractor.

Many forms of apparatus exist for coupling an agricultural implement to a tractor, and a system which is becoming increasingly popular uses what is referred to as a "three-point hitch". This provides for three points of attachment between the tractor and the implement, with the two lower points being on a horizontal line perpendicular to the direction of movement of the tractor. By this means it is possible to raise or lower the implement by hydraulic rams attached to the tractor.

The implement may be secured to the three-point hitch by pins, bolts and the like, but a quick-release mechanism is more convenient. One form of quick release mechanism involves attaching to the threepoint hitch on the tractor a substantial triangular frame with the apex of the triangle at the top. The implement carries a similarly-shaped frame of channel-shaped cross-section, but with the horizontal member of the triangle omitted to form an inverted Vee. The dimensions and shape of the two frames are such that the triangle carried by the tractor may be inserted into the frame on the implement from beneath, and the implement may then be lifted by movement of the three-point hitch. Frequently the horizontal member of the "triangle" carried by the tractor is omitted to save weight, particularly if the three-point hitch gives the necessary rigidity.

Coupling apparatus of this type requires some form of latch to prevent accidental displacement of the implement, for example when in contact with the ground. Again several types of latch exist, these usually being manually operated and spring-loaded into the latching position.

A further requirement is for a safety device to prevent loss of the implement when travelling on the public highway, and it is an object of the invention to provide coupling apparatus fitted with such a device.

According to the present invention there is provided coupling apparatus for coupling an agricultural implement to a tractor, which includes a first coupling member arranged to be secured to the implement and in the form of an inverted-Vee with each arm of channel-shaped cross-section, a second coupling member arranged to be secured to the tractor and of such shape and dimensions as to be locatable inside the first coupling member, disengagable latching means carried by the second coupling member and engagable with the first coupling member to prevent their disengagement, and locking means operable to prevent the disen gagementofthe latching means.

An embodiment of the invention will now be describd with reference to the accompanying drawings, in which: Figure 1 is a front view of a frist coupling member; Figure 2 is a similar view of a second coupling member; Figure 3 is a sectional side view of the engaged coupling members showing the latching and locking means, and Figure 4 is a front view of the latching and locking means.

Referring now to Figure 1, this shows the first coupling member which is arranged to be carried on the implement. Basically the member consists of two pieces of metal channel 10 welded together to form an inverted Vee, with the open sides of the channel facing one another. The lower end of each channel carries a mounting lug 11 by which it is secured to the implement, and a similar lug (not shown) is fixed to the top of the member. The apex of the member is strengthened by a plate 12, which contains an aperture 13 to receive the latching means to be describd later. Across the bottom of the aperture 13 is secured a striking plate 14.

The second coupling member is shown in Figure 2. This consists of two metal member 16 secured together to form a second inverted-Vee of the same dimensions as the first coupling member. The lower end of each member 16 carries a mounting lug 17 for attachment to the three-point linkage on the tractor, whilst a third mounting point provided by a pair of plates 18 secured near to the apex of the coupling member. The coupling member is strengthened by a plate 19 near its apex and a pair of fillets 20. The plate 19 carries the latching means on the form of a spring-loaded hook 21 which may be disengaged by means of a handle 22. Plate 19 also carries the locking means which will be described in detail later.

A roller 23 is secured to the apex of the frame to assist with the engagement of the two coupling members.

Figure 3 and 4 illustrate the construction and operation of the latching means and the locking means. The drawing shows the plate 19 carried by the second coupling member and also parts of the plate 12 carried by the first coupling member. The striking plate 14 secured to plate 12, is shown engaged by the hook 21. A projection 24 from the base of the hook limits movement of the hook when being disengaged by coming into contact with the plate 19.

Plate 19 also carries the locking means. A housing 25 fastened to plate 19 contains a bolt 26 and a compression spring 27 operable to urge the bolt upwards. The lower end of the housing 25 is provided with two slots 28 and 29 of different length into which a bent-over handle 30 on the end of the bolt 26 may be engaged. When the handle 30 is engaged in the longer slot 28, the bolt is able to rise and enter a hole drilled in the underside of the hook 21. This prevents rotation of the hook. When the handle 30 of the bolt is engaged in the shorter slot 29 the bolts 26 is kept disengaged from the hook 21.

In normal use the hook 21 is relied upon to prevent disengagement of the two coupling members. When disengagement is required the hook may be operated by a wire or cord secured to the handle 22 and operated by the tractor driver from the cab of the tractor. The locking bolt is kept disengaged.

If the locking bolt is to be used the driver must dismount and engage the bolt in the hook. It is not possible to release the bolt from the cab of the tractor, and this prevents its accidental release, say when the tractor is moving along a road. The bolt may only be released by the positive action of the driver, requiring him to leave his cab.

Although the locking device is very simple, it is nevertheless effective in preventing accidental release of the hook 21 and loss of a carried implement.

The above description has describd the second coupling member as being carried on a three-point linkage. Other means of mounting the coupling member are possible. For example it may be secured to the fore-loader arms of a tractor so equipped.

Similarly, the first coupling member may be secured to the implement in any suitable manner, such as by welding.

The invention is equally applicable to implements carried on the front or the rear of a tractor.

Claims

1. Coupling apparatus for coupling an agricultural implement to a tractor, which includes a first coupling member arranged to be secured to the implement and in the form of an inverted-Vee with each arm of channel-shaped cross-section, a second coupling member arranged to be secured to the tractor and of such shape and dimensions as to be locatable inside the first coupling member, disengagable latching means carried by the second coupling member and engagable with the first coupling member to prevent their disengagement, and locking means operable to prevent the disen gagementofthe latching means.

2. Apparatus as claimed in Claim 1 in which the latching means comprise a spring-loaded hookshaped member rotatable about an axis so as to engage part of the first coupling member.

3. Apparatus as claimed in Claim 2 in which the locking means comprises a spring-loaded bolt operable to enter a hole in the hook-shaped latching member to prevent the rotation thereof.

4. Apparatus as claimed in Claim 3 in which the spring-loaded bolt may be maintained in either of two positions in one of which it is in engagement with the latching means.

5. Coupling apparatus for coupling an agricultural implement to a tractor substantially as herein described with reference to the accompanying drawings.