The invention relates to a device carried on an agricultural
tractor for the secure keeping of implement coupling balls, of various categories,
provided with a through-hole.
Agricultural tractors are equipped at the rear with attachment
gear for mounted and towed agricultural implements. The known attachment gear consists
of two lower links and an upper link which together form a 3-point linkage. The
links at their free ends each possess a coupling device for engagement by suitably
formed attachment pins on the implement. In order to avoid tensions in the 3-point
linkage and wear to the tractor and implement coupling parts, axially secured coupling
balls, which are held by the link coupling devices, are provided which are pushed
onto the implement attachment pins during the attachment of the implement.
The coupling ball to be held by the coupling device of
the upper link in this case is somewhat smaller in diameter than the coupling balls
to be held by the lower links. In addition, different variants of coupling balls
exist. Thus, coupling balls with or without cylindrical shoulders on one or both
orifices of the through-holes and also coupling balls with one-sided deflector profiles
Agricultural tractors have the capacity to hold implements
of different categories or sizes. Depending upon the category of the equipment the
implement attachment pins have different diameters. Accordingly, the associated
coupling balls have through-holes of different diameters. The outside diameter of
the balls, however, remains constant, since the link coupling devices cannot be
exchanged. Each agricultural tractor, therefore, carries at least 3 coupling balls
and frequently more coupling balls when implements of different categories are to
be used. Up to now the coupling balls have been kept in a toolbox, which is generally
in the step area of the driver's cab and therefore remote from the rear region with
the implement attachment gear.
In principle, every effort is made to fit and remove an
implement without using tools, thus without accessing the contents of the toolbox.
This requirement however cannot be met if implements of different categories are
to be used in succession.
It is an object of the invention to provide a device for
the secure keeping of implement coupling balls which permits access at all times
to the required coupling balls regardless of their category.
Thus according to the present invention there is provided
a holder carried on an agricultural tractor for holding implement coupling balls,
the holder being characterised by comprising a rear wall, two side walls and an
open upper end, the side walls retaining the balls within the holder with the inside
surfaces of the side wall in contact with portions of the spherical surfaces of
the balls which face away from the rear wall, and bias means for biasing the balls
into contact with the inside surfaces of the side walls.
Thus, a holder is created which can be mounted in direct
proximity to the attachment gear at the rear of the vehicle, for example inside
a wheel cover. The coupling balls are, therefore, always in proximity to the place
where they are needed.
The holder may be provided with an adaptor element for
partially enclosing a ball of a smaller category than the holder was designed to
hold, the adaptor element being positioned between the smaller category ball and
the side walls so that the smaller ball and adaptor element together occupy a similar
volume to the volume occupied by a ball of the category which the holder was designed
For reasons of space, the rear wall may extend over a length
of three coupling balls.
A locking member is preferably provided which extends between
side walls to prevent the balls falling inadvertently from the holder.
An arrangement of the holder such that the coupling balls
are held without shaking is created due to the fact that, the bias means forces
the balls into contact with the inside surfaces of the side walls.
Conveniently, the bias means is provided by an arched spring
arranged between the rear wall and the balls.
An exemplary embodiment of the invention is described below,
by way of example only, with reference to the accompanying drawings in which:-
- Fig. 1
- is a view of an implement coupling ball holder from bottom right;
- Fig. 2
- is a view of the holder filled with three coupling balls of the same category
from top left;
- Fig. 3
- is a cutaway view of the holder on a level with the upper coupling ball in Fig.
- Fig. 4
- is a cutaway view of the holder on a level with the middle coupling ball in
- Fig. 5
- is a cutaway view of the holder on a level with the lower coupling ball in Fig.
- Fig. 6
- is a view of a holder for coupling balls of category 3 after insertion of an
adapter element, in which a coupling ball of category 2 is held,
- Fig. 7
- is a cutaway view of the holder and the adapter element in accordance with Fig.
6 on a level with the lower coupling ball,
- Fig. 8
- is a perspective view of the adapter element,
- Fig. 9
- is a view of the holder in accordance with Fig. 6 additionally filled with two
coupling balls of category 3 and
- Fig. 10
- is a view of the holder in accordance with Fig. 9 with coupling ball removed
from the adapter element.
The implement coupling ball holder shown in Figs. 1 and
2 is intended to hold coupling balls of categories 3 and 3-2. More particularly,
it is designed for the external dimensions of the coupling balls of the lower links,
since these have a larger outside diameter than the coupling ball of the upper link.
Category 3-2 represents an intermediate size, the coupling balls having the same
outside diameter as coupling balls of category 3, however possessing a smaller through-hole
similar to the coupling balls of category 2.
The holder is manufactured by bending a metal sheet and
has a very simple structure. It comprises a rear wall 3, two side walls 4 and a
base 5 attached to the lower part of the rear wall 3. A space 4a is defined between
the side walls 4. Two lugs 6 are provided with holes for bolting the holder onto
a tractor, in particular onto a wheel cover or fender, not illustrated. The length
of the holder is sufficient to hold three coupling balls 1, 2.
As shown particularly in Figs. 3 to 5, the side walls 4
are formed to act as a roof of the holder. Their shape and distance from each other
are designed in such a way that the coupling balls 1, 2 can only be slid into the
space 4a shown from the open upper end lying opposite the base 5. In this normal
orientation their through-holes 1a, 2a run perpendicularly to the rear wall 3. The
side walls 4 embrace the inserted coupling balls 1, 2 so that these cannot fall
out of the holder on the open front side, but also allow coupling balls 2 with a
deflector profile 2b (Fig. 5) to be stored. The spherical surfaces of the balls
which face away from the rear wall 3 contact the inside of wall regions 4b under
action of a force pushing the coupling balls 1, 2 away from the rear wall 3. Here
a gap 7, whose width in the case of coupling balls of category 3-2 (Fig. 3) is greater
than in the case of coupling balls of category 3, remains between the rear wall
3 and the adjacent face of the balls (Fig. 4 and 5). An arched steel spring 8, which
extends over the entire length of the holder, is fixed to the rear wall 3 and supplies
the necessary force to press the coupling balls 1, 2, as they are being inserted
into the holder, against the inside of the wall regions 4b. The spring 8 is accommodated
in this gap 7. Since the steel spring 8 and the coupling balls 1, 2 are made from
the same metal, the coupling balls 1, 2 slide very easily on the steel spring 8,
so that, although held without shaking, they can be very easily taken in and out
of the holder. So that the coupling balls 1, 2 cannot fall out of the holder by
strong impacts, a locking pin 9 is provided, which is pushed in above the uppermost
coupling ball 1 and held in openings 4c in the side walls 4.
The holder described in Figs. 6 to 10 is supplemented by
an adapter element 10, which renders the possibility of also holding coupling balls
of a category smaller than those, for which the holder is designed, in a secure
and rattle-free way. In the present exemplary embodiment although only one adapter
element is used, it goes without saying that the adapter elements are formed so
that, arranged one above the other, they require no more space than the coupling
balls, which they replace.
The adapter element 10 has two side walls 10a, which are
connected to one another in the lower final region so as to form a U-shape. As particularly
evident from Fig. 7, the walls 10a are bent in such a manner that they form inner
and outer wall remote regions 10b, 10c, between which a coupling ball of category
2 is stored with only slight play. Ribs 10d, which lie against the side walls 4
of the holder are provided on the side walls 10a so that the adapter element 10
can be easily pushed into the latter, until a rib 10e rests on the base 5. The upper
end of the side walls 10a has angled surfaces 10f, on which the coupling ball 2
of category 3, located above these, rests. With the corresponding length of the
side walls 10a this coupling ball 2 is on exactly the same level as it would be
if, in place of the adapter element 10, a coupling ball of category 3 were inserted
into the holder. In addition, the side walls 10a are provided with recesses 10g,
which the adapter element 10 and the coupling ball 11 to be secured by the locking
pin 9. The distance of the adapter element 10, and thus of the stored coupling ball
11, from the rear wall 3 is coordinated in such a way that the steel spring 8 presses
the coupling ball 11 onto the wall regions 10c, just as the coupling balls 2 press
against the wall regions 4b.