Patent Description:
Hooks adapted to automatically accommodate, and to automatically keep locked, the ball joint of an agricultural tool are known in the art.

For example, hooks comprising a main hook-shaped body and provided with a seat for hooking a ball joint, a plug operating within said main body and movable between a first locking position for locking said joint on said seat and a second releasing position for releasing said ball joint from said seat, and outer means to drive the displacement of said plug between said first position and said second position, are known.

For example, the patent <CIT>, describes a hook of this type.

Moreover, also the document <CIT>, describes a hook for agricultural machine. Such coupling hook comprises a housing defining a recess within which a ball for supporting a pin of the tool is accommodated. The hook further comprises a spring-like locking catch. The catch is pivoted around a support pin with clearance in the direction of a first direction connecting the center of the recess to a point of contact between the locking catch and the ball in the recess. The coupling hook further comprises a locking catch which engages the locking catch within a recess thereof such as to define the locking position.

Although extremely efficient in allowing a secure connection of the hook to the ball joint to which it is combined, the solutions of the known art are not devoid of drawbacks.

In fact, whenever the plug of the hook is subjected to a sudden and unexpected force on its front portion, the one in the proximity of the ball joint on which the plug acts, preventing it from coming out of the seat of the main body, the plug could suffer a sudden backward movement. This could cause not only the breaking of the components that are in the hook and, with it, the pins, elastic elements and other components that are in the body of the hook to come out of the body, but also and especially the joint to come out of the seat and, consequently, the tool to be lost. Thus, object of the present invention is to make a hook that is both simple from a structural point of view and that also ensures a greater level of safety compared to the one ensured by the hooks of known art.

Further object of the present invention is to make a hook consisting of the same number of components currently used for the hooks of known agricultural machines, although ensuring a greater degree of safety.

Finally, object of the present invention is to make a hook that is anyhow simple to manufacture and assemble.

These and further objects are achieved by means of a hook for agricultural machine according to claim <NUM>, comprising a main hook-shaped body provided with a seat for hooking a ball joint, and a plug operating within said main body and movable between a first locking position for locking said joint on said seat and a second releasing position for releasing said ball joint from said seat, said hook further comprising safety means adapted to prevent the untimely moving back of said plug from said first locking position to said second releasing position in the presence of forces acting on the front end of said plug, said safety means comprising a blind recess obtained inside said main body and a pin directly or indirectly combined with said plug and adapted to come into contact with the inner surface of said blind recess at least when said plug is subjected to said forces acting on its front end such as to assume a third intervention position of said safety means between said first position and said second position, wherein said ball joint is further locked on said seat.

Thanks to the presence of the safety means, it is possible to stop the moving back of the plug which, whenever in the first position and whenever subjected to a sudden force, would be forced to be displaced from the first position such as to reach the second position. Thanks to the solution claimed, not only the breaking of the hook is prevented, but especially the ball joint is prevented from coming out of the seat of the main body and, thus, the tool to which the ball joint is integrally constrained from being lost. In fact, the plug, even if subjected to a sudden force, cannot reach the second position but reaches the aforesaid third position at the limit. However, in such position, the plug still prevents the ball joint from coming out of the hooking seat.

Moreover, the operation of the hook is also ensured whenever some components present inside the hook itself, such as elastic dowels and/or springs, should break. Also in a situation of this type, the ball joint would still be prevented from coming out of its seat.

Still, said hook further comprises outer means to drive the displacement of said plug between said first position and said second position.

Moreover, according to the invention, said drive means comprise a lever pivoted to the back part of said plug around a first axis; the same lever is advantageously operable from the outside of the main body and is pivoted to said main body around a second axis distinct from said first axis.

The first and second axes are advantageously horizontal and, thus, parallel to each other.

It should be noted that the mutual rotation between the lever and the plug occurs around the first, preferably horizontal, axis, whereas the rotation of the lever with respect to the main body occurs around the second, preferably horizontal, axis.

Still, said main body comprises an inner hollow within which said pin of said safety means runs at the switching of said plug from said first position to said second position and vice-versa; said blind recess is arranged at the end of said inner hollow, in the proximity of the position reached by said pin when said plug reaches said first locking position.

Still, said inner hollow is in the shape of an arc of circumference having its center in a point of said second hinge axis for said lever.

Moreover, said blind recess is formed along a direction substantially transversal to said hollow. Particularly, said inner surface of said recess has curvilinear shape whose concavity is opposite that of said inner hollow.

Advantageously, said lever is pivoted to said plug by means of said pin of said safety means.

Such solution allows to reduce the components of the hook according to the solution claimed to the minimum. In fact, the pin of the safety means would be used not only as a catch to prevent the moving back of the plug in the event of sudden forces to which it could be subjected, but also as a pin around which the lever rotates with respect to the plug when switching from the first position to the second position and vice-versa. In practice, the first horizontal axis coincides with the longitudinal axis of such pin.

Always according to the embodiment described herein, the hook comprises elastic means arranged within the main body and adapted to cooperate with the plug and/or with the lever to keep said plug in said first position.

Finally, said drive means comprise an outer handle combined with said lever.

These and further aspects of the present invention will become clearer in the following detailed description of a preferred embodiment provided herein by way of example only and without limitations, with reference to the accompanying figures, in which:.

With particular reference to such <FIG> denotes the hook according to the invention.

As shown in <FIG>, <FIG>, <FIG>, the hook <NUM> for agricultural machine comprises a main hook-shaped body <NUM> preferably made by hot pressing (forging) and then machined by means of a numerical control machine, provided with a seat <NUM> for hooking a ball joint <NUM>, and a plug <NUM> operating within the main body <NUM> and movable between a first locking position P1 for locking the joint <NUM> on the seat <NUM> (see <FIG>) and a second releasing position for releasing the ball joint <NUM> from the seat <NUM> (see <FIG>). The hook <NUM> according to the invention described herein further comprises outer means <NUM> to drive the displacement of the plug <NUM> between the first position P1 and the second position P2.

The hook <NUM> further comprises safety means adapted to prevent the untimely moving back of the plug <NUM> from the first locking position P1 to the second releasing position P2 in the presence of forces F acting on the front end 5a of the plug <NUM>. Such safety means comprise a blind recess <NUM> (see <FIG>) formed inside the main body <NUM>, for example by machining with a numerical control machine, and a pin <NUM> integral with the plug <NUM> and adapted to come into contact with the inner surface 10a of the blind recess <NUM> at least when the plug <NUM> is subjected to the aforesaid forces F acting on its front end 5a such as to make said safety means assume a third intervention position P3, between the first position P1 and the second position P2 (see <FIG>). In such third position P3 the plug <NUM> anyhow further prevents the ball joint <NUM> from coming out of the seat <NUM>.

The outer drive means <NUM> comprise a lever <NUM> pivoted to the upper part 5b of the plug <NUM> around a first horizontal axis A. Such lever <NUM> is operable by a user from the outside of the main body <NUM> and is in turn pivoted to said main body <NUM> around a second horizontal axis B. The first horizontal axis A is distinct from and parallel to the second horizontal axis B. In practice, the lever <NUM> is thus rotatably constrained to the plug <NUM> around the first axis A and is also rotatably constrained to the main body <NUM> around the second axis B parallel to and distinct from the first axis A.

According to the embodiment described herein, the main body <NUM> comprises an inner hollow <NUM> within which the pin <NUM> of the safety means runs as the plug <NUM> switches from the first position P1 to the second position P2 and vice-versa. The blind recess <NUM> is arranged at the end 30a of the inner hollow <NUM>, at the position reached by the pin <NUM> when the plug <NUM> reaches the first locking position P1.

In particular, the inner hollow <NUM> is in the shape of an arc of circumference having its center in a point of the second hinge axis B for the lever <NUM>.

Moreover, the blind recess <NUM> is formed along a direction substantially transversal to the main direction of the inner hollow <NUM>. Still, the inner surface 10a of the recess <NUM> has curvilinear shape whose concavity is opposite that of the inner hollow <NUM>. Advantageously, the lever <NUM> is pivoted to the plug <NUM> by means of the pin <NUM> of the safety means. In practice, the pin <NUM> allows the mutual rotation between the plug <NUM> and the lever <NUM>.

This allows to considerably reduce the number of components needed to make the hook <NUM>. In fact, the pin <NUM> is used both as a hinge pin between the plug <NUM> and the lever <NUM> and as an element which is used to prevent the backward movement of the plug <NUM> from its first position P1, whenever unexpected forces F are applied at the front portion 5a of the plug <NUM>.

Still, the hook comprises elastic means arranged within the main body <NUM> and adapted to cooperate with the plug <NUM> and, consequently, with the lever <NUM> to constantly keep the plug <NUM> in its first locking position P1. Such elastic means comprise a first spring <NUM>, some elastic pins and a second spring <NUM> which cooperate to prevent the plug <NUM> from being able to switch from its first locking position P1 to its second releasing position P2. In practice, such elastic means oppose a certain force to the switching from the first position P1 to the second position P2, such as the plug <NUM>, in its initial condition, is always kept in its first position P1.

The user will act on the outer drive means <NUM>, i.e. mainly on the handle <NUM> of the lever <NUM>, to insert the ball joint <NUM> at the seat <NUM>, by displacing the plug <NUM> from its first position P1 to its second position P2. During such displacement, the pin <NUM> runs within the hollow <NUM> without interruptions. Once the joint <NUM> has been inserted into the seat <NUM>, the user releases the handle <NUM>. At this point, the elastic means <NUM> push the plug <NUM> in abutment against the ball joint <NUM>. The elastic means are also the ones that prevent the joint <NUM> from coming out of the seat <NUM> during the operation of the hook <NUM>.

Finally, the drive means <NUM> comprise an outer handle <NUM> combined with the lever <NUM> to be operated from the outside.

Claim 1:
Hook (<NUM>) for agricultural machine, comprising a main hook-shaped body (<NUM>) provided with a seat (<NUM>) for hooking a ball joint (<NUM>), and a plug (<NUM>) operating within said main body (<NUM>) and movable between a first locking position (P1) for locking said joint (<NUM>) on said seat (<NUM>) and a second releasing position for releasing said ball joint (<NUM>) from said seat (<NUM>), said hook (<NUM>) further comprising safety means adapted to prevent the untimely moving back of said plug (<NUM>) from said first locking position (P1) to said second releasing position (P2) in the presence of forces (F) acting on the front end (5a) of said plug (<NUM>), said safety means comprising a blind recess (<NUM>) obtained inside said main body (<NUM>) and a pin (<NUM>) directly or indirectly combined with said plug (<NUM>) and adapted to come into contact with the inner surface (10a) of said blind recess (<NUM>) at least when said plug is subjected to said forces (F) acting on its front end (5a) such as to assume a third intervention position (P3) of said safety means between said first position (P1) and said second position (P2), wherein said ball joint (<NUM>) is further locked on said seat (<NUM>), wherein outer means (<NUM>) drive the displacement of said plug (<NUM>) between said first position (P1) and said second position (P2), and vice-versa, wherein said outer drive means (<NUM>) comprise a lever (<NUM>) pivoted to the back part (5b) of said plug (<NUM>) around a first axis (A), said lever (<NUM>) being operable from the outside of said main body and further being pivoted to said main body (<NUM>) around a second axis (B), said first axis (A) being distinct from said second axis (B), wherein said lever (<NUM>) is pivoted to said plug (<NUM>) by means of said pin (<NUM>) of said safety means.