GB1568566A - Draw gear for farm tractors - Google Patents

Description

(54) DRAW GEAR FOR FARM TRACTORS (71) We, DAIMLER-BENZ AKTIEN- GESELLSCHAFT, a company organised under the laws of the Federal Republic of Germany, of Stuttgart-Unterturkheim, Federal Republic of Germany, 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 invention relates to draw gear for farm tractors which can be modified according to the purpose for which it is to be used, with an adjustable draw bar pivoting round a vertical axis for trailer implements and with a lower semi-trailer draw hook for heavy trailers.

The semi-trailer draw hook, which is required to take heavy supported loads of up to 1.8 t, is in many cases fixed rigidly to the drawbar. However, it may also be detachable. The normal adjustable drawbar, on the other hand, is used only for implements to be trailed. For example it may draw a plough and the latter may be disposed offset to one side of the tractor, to which end the drawbar is swung sideways round said vertical axis and secured in this position by pintles.

For trailer work, when two-wheel trailers in particular may represent the said heavy supported load, the semi-trailer draw hook is used which is mounted lower down. Assembly dimensions for this are standardised and consequently if it is required to use both systems on the same vehicle there are problems of space. A further cause of such difficulties is the fact that allowance has to be made for a drive shaft running above the drawbar for the connection of mechanisms which have to be driven on the trailer. The possibility of combining both connection systems with one draw gear had also been rendered difficult previously through the fact that with the previously known standardised semi-trailer draw hook a safety device was pivoted round a horizontal transverse axis and hence required space upwardly.

The object if the invention is to propose a space-saving arrangement by means of which it is possible to accommodate in the available space a combination of the two trailer systems and, with a high-speed changing operation, to bring into use the semi-trailer draw hook or the adjustable drawbar.

According to the present invention there is provided draw gear for farm tractors including a first adjustable drawbar pivotable about a vertical axis, for trailer implements, the drawbar being selectively replaceable by a shorter drawbar, and a semitrailer draw hook, located in use therebeneath, for heavy trailers, the shorter drawbar carrying a guiding member and a holding-down part and being displaceable to a lateral position, clear of the draw hook, in which the guiding member facilitates the insertion of a trailer eye in the draw hook, the holding-down part when the shorter drawbar is in a mid position serving as a locking mechanism to prevent a trailer eye which has been inserted in the semitrailer draw hook from being released.

From the purely constructional point of view this draw gear may include laterally spaced angular fixing elements adapted to be secured to the tractor, between which elements upper and lower guide plates for the first adjustable drawbar, the lower of which is welded to the semi-trailer draw hook, are secured in such a way that they are separated by a distance corresponding at least to the thickness of the first adjustable drawbar. The shorter adjustable bar can then be introduced between these guide plates for the adjustable drawbar and then retained there by a pintle and by means of further pintles can be secured in the mid position or in a side position.

In a further development of the invention, however, the draw gear may be constructed without a fixed semi-trailer draw hook if the latter, together with a shorter adjustable bar, can be introduced between the guide plates for the adjustable draw bar and fixed there, the shorter bar carrying the guiding member and the holding-down part. In such a case, in the region of the adjustable drawbar guide plates the semitrailer draw hook and the shorter adjustable bar are together only of such a thickness that they can both be pushed into the intermediate space between the two adjustable drawbar guide plates. Consequently the semi-trailer draw hook can be designed so as to project downwardly to a lesser extent, thus providing greater ground clear ante. The space between the two adjustable drawbar guide plates, previously occupied by the adjustable drawbar, is now divided between a carrier for the semitrailer draw hook and the adjustable bar which can be pushed in between the plate, the carrier for the semi-trailer draw hook being conveniently thicker than the section of the adjustable bar which has to be pushed in between the adjustable drawbar guide plates. Here, too, three pintles are provided; one for fixing the parts between the adjustable drawbar guide plates and two for securing the adjustable bar in the side or the middle position depending on whether a trailer eye is to be inserted easily in the semi-trailer draw hook by means of the guiding member, or whether the eye of a trailer inserted in the semi-trailer draw hook has to be secured by the holding-down part.

Then by drawing out the fixing pin, the complete unit according to the invention, which serves to connect up a trailer and to secure it in the coupled position, can be changed for an adjustable drawbar with which only trailer implements can be pulled.

The invention will now be described by way of example with refrence to the accompanying drawings in which: Figure 1 a side elevation of draw gear for a farm tractor with a normal adjustable drawbar for farm implements and beneath it, a semi-trailer draw hook for heavy supported loads, Figure 2 a corresponding side elevation wherein, according to the invention, the adjustable drawbar is replaced by a short adjustable bar with a guiding member and a holding-down part, Figure 3 a plan view of the draw gear according to the invention wherein the short adjustable bar with the guiding member is set in such a way that a trailer eye can easily be inserted in the semi-trailer draw hook, Figure 4 a plan view of the same draw gear wherein only the adjustable bar with the holding-down part is brought into, and secured by a pintle in the position in which the attached eye of the trailer is secured by the holding-down part, Figure 5 a side elevation of a further embodiment of the invention with a semitrailer draw hook giving considerable ground clearance.

In the draw gear represented in Figure I a normal adjustable draw bar 4 of known type is pushed between upper and lower guide plates 2, 3, on, or secured to a farm tractor the draw bar being adapted to have agricutural implements, for example a plough, secured thereto. The adjustable drawbar 4 is held by a pintle 5 so as to be capable of pivotal movement about a vertical axis. It can be locked in a middle position by further pintles 6 and 7 or held in a lateral position that is, at an angle to the longitudinal centre line of the tractor (in plan view) by one of these two pintles 6 or 7.

Figure 2 shows a short adjustable bar 8 inserted in place of the adjustable drawbar 4. This, too, is secured by a pintle 5 and, as shown in Figure 3, retained in a selected position by the pintle 7, in which position a guiding member 9 facilitates the introduction of the eye of a trailer into a semitrailer draw hook 11.

Another feature of the construction of the draw gear is the angular fixing elements 12 which are secured to the tractor 13 by, for example, welding. The two guide plates for the ajustable drawbar 2 and 3 are secured by for example being welded, between the angular fixing elements 12 at a distance from one another such that the normal adjustable drawbar 4 or the short adjustable bar 8 can be inserted easily. The semi-trailer draw hook 11 is welded on the lower guide plate 3.

Now, when the eye of a trailer has been placed in the semi-trailer draw hook 11 the pintle 7 is released and the short adjustable bar 8 brought into the middle position as shown in Figure 4. Consequently a hold irlg-down part 14 which is welded on the short adjustable bar 8 comes over the eye of the hitched up tractor, thereby preventing its accidental disconnection. The middle position of the short adjustable bar 8 is secured by insertion of the pintles 6 and 7.

Figure 5 shows a further embodiment of the draw gear according to the invention wherein the semi-trailer draw hook is no longer welded fast to the lower guide plate of the adjustable drawbar. Instead, a short adjustable bar 15 with its carrier part 16 and the carrier 17 of the semi-trailer draw hook 18 are inserted in the space between the guide plates 2 and 3 for the adujstable drawbar. The carrier part 16 and the carrier 17 together are of a width which is permitted by the interspace between the two adjustable drawbar guide plates 2 and 3.

The semi-trailer draw hook 18 projects downwardly to a much lesser degree so that greater ground clearance becomes possible through this construction.

Here, again, the short adjustable arm 15 is provided with a guiding member 19 and a holding-down part 20, of which the guiding member, again, serves to facilitate the insertion of a trailer eye and the holdingdown part 20 to secure it.

In a modification of this embodiment the carrier 17 of the semi-trailer draw hook 18 is of a special construction. It has lateral projections 21 which extend forward as far as the angular fixing elements 12 thereby preventing any sideways shifting of the semi-trailer draw hook. The outlines of the projections 21 are represented in Figure 4 - which essentially shows the outline of the short adjustable arm 8 -- by means of dash-dot lines.

WHAT WE CLAIM IS: 1. Draw gear for farm tractors including a first adjustable drawbar, pivotable about a vertical axis, for trailer implements the drawbar being selectively replaceable by a shorter drawbar, and a semi-trailer draw hook, located in use therebeneath, for heavy trailers, the shorter drawbar carrying a guiding member and a holding-down part and being displaceable to a lateral position, clear of the draw hook, in which the guiding member facilitates the insertion of a trailer eye in the draw hook, the holding down part when the shorter drawbar is in a mid position serving as a locking mecha nism to prevent a trailer eye which has been inserted in the semi-trailer draw hook from being released.

2. Draw gear according to claim 1, further including laterally spaced angular fixing elements adapted to be secured to the tractor, between which elements upper and lower guide plates for the first adjustable drawbar, the lower of which is welded to the semi-trailer draw hook, are secured in such a way that they are separated by a distance corresponding at least to the thickness of the first adjustable drawbar.

3. Draw gear according to claim 2, wherein the shorter adjustable bar is adapted to be located between the adjustable drawbar guide plates and secured there by a pintle and is securable in the mid position or in a lateral position by means of further pintles.

4. Draw gear according to the claim 2 or 3 wherein the semi-trailer draw hook, together with the shorter adjustable bar can be positioned between the guide plates and fixed there.

5. Draw gear according to claim 1 further including laterally spaced angular fixing elements adapted to be secured to the tractor between which elements upper and lower guide plates are secured and spaced by such a distance that the semi-trailer draw hook and the shorter adjustable bar can be positioned therebetween.

6. Draw gear according to claim 5, wherein the semi-trailer draw hook is guided by lateral projections which extend forward as far as the angular fixing elements.

7. Draw gear for a farm tractor substantially as described herein with refrence to and as illustrated in, Figures 1 to 4 or Figs 1 to 4 as modified by Figure 5 of the accompanying drawings.

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

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. drawbar. The carrier part 16 and the carrier 17 together are of a width which is permitted by the interspace between the two adjustable drawbar guide plates 2 and 3. The semi-trailer draw hook 18 projects downwardly to a much lesser degree so that greater ground clearance becomes possible through this construction. Here, again, the short adjustable arm 15 is provided with a guiding member 19 and a holding-down part 20, of which the guiding member, again, serves to facilitate the insertion of a trailer eye and the holdingdown part 20 to secure it. In a modification of this embodiment the carrier 17 of the semi-trailer draw hook 18 is of a special construction. It has lateral projections 21 which extend forward as far as the angular fixing elements 12 thereby preventing any sideways shifting of the semi-trailer draw hook. The outlines of the projections 21 are represented in Figure 4 - which essentially shows the outline of the short adjustable arm 8 -- by means of dash-dot lines. WHAT WE CLAIM IS:

1. Draw gear for farm tractors including a first adjustable drawbar, pivotable about a vertical axis, for trailer implements the drawbar being selectively replaceable by a shorter drawbar, and a semi-trailer draw hook, located in use therebeneath, for heavy trailers, the shorter drawbar carrying a guiding member and a holding-down part and being displaceable to a lateral position, clear of the draw hook, in which the guiding member facilitates the insertion of a trailer eye in the draw hook, the holding down part when the shorter drawbar is in a mid position serving as a locking mecha nism to prevent a trailer eye which has been inserted in the semi-trailer draw hook from being released.

2. Draw gear according to claim 1, further including laterally spaced angular fixing elements adapted to be secured to the tractor, between which elements upper and lower guide plates for the first adjustable drawbar, the lower of which is welded to the semi-trailer draw hook, are secured in such a way that they are separated by a distance corresponding at least to the thickness of the first adjustable drawbar.

3. Draw gear according to claim 2, wherein the shorter adjustable bar is adapted to be located between the adjustable drawbar guide plates and secured there by a pintle and is securable in the mid position or in a lateral position by means of further pintles.

4. Draw gear according to the claim 2 or 3 wherein the semi-trailer draw hook, together with the shorter adjustable bar can be positioned between the guide plates and fixed there.

5. Draw gear according to claim 1 further including laterally spaced angular fixing elements adapted to be secured to the tractor between which elements upper and lower guide plates are secured and spaced by such a distance that the semi-trailer draw hook and the shorter adjustable bar can be positioned therebetween.

6. Draw gear according to claim 5, wherein the semi-trailer draw hook is guided by lateral projections which extend forward as far as the angular fixing elements.

7. Draw gear for a farm tractor substantially as described herein with refrence to and as illustrated in, Figures 1 to 4 or Figs 1 to 4 as modified by Figure 5 of the accompanying drawings.