A star-wheel rake including a frame, at least one front rake wheel and a rear drive wheel, coupled with each other so that the rotation of the rear drive wheel causes the rotation of the front rake wheel and connected to the frame so that the front rake wheel is lifted from the ground when the rear drive wheel is in contact with the ground.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to Italian Patent Application No. 102015000021005 filed on Jun. 5, 2015, the disclosure of which is incorporated by reference.

TECHNICAL FIELD

The present invention relates to a star-wheel rake.

BACKGROUND OF THE INVENTION

As is known, rakes are used in farming for turning over forage after cutting and accumulating the processed material in rows, normally referred to as windrows.

One of the commonly used rakes is the star-wheel type.

A star-wheel rake comprises a plurality of rakes or star wheels, which are idly mounted on a frame about respective parallel axes and, in practice, form rotating rakes. The rake wheels, with the same diameter, are oblique with respect to a direction of travel in the working configuration and are set in rotation by contact with the ground during the forward travel of the rake. Each rake wheel is equipped with an outer ring of coplanar teeth, shaped to collect the forage and move it sideways due to the combine effect of the rake advancing in the direction of travel and the rotation of the rake wheel about the respective axis. Furthermore, the rake wheels are placed side by side so that the forage moved from the more forward wheels with respect to the direction of travel is collected by the more rearward adjacent wheels. In this way, the rake wheels define a working front and move the forage collected on the working front during forward movement towards a discharge side of the rake, where a windrow is formed. The upstream (more forward) wheels along the working front can partially overlap the immediately adjacent more downstream (more rearward) wheels, to avoid losing the material being processed.

Star-wheel rakes have the advantage of a very simple structure, which does not require specially provided drives for the rake wheels. As already mentioned, the rake wheels are actually idle and rotate due the effect of contact of the teeth with the ground during forward movement. Star-wheel rakes are therefore inexpensive and relatively immune to malfunctioning, and this makes their use fairly widespread.

However, the same mechanism that drives the rake wheels, also causes soil and dust to be raised, which mixes with the collected forage and accumulates in the windrows. Dirt in the forage is obviously unwelcome, because it may interfere with the aeration and drying process and, in general, degrades the quality of the product. Thus, on one hand, star-wheel rakes are inexpensive and good value for money, but on the other, the results they provide are often unsatisfactory.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide a star-wheel rake that enables overcoming or at least mitigating the described limitations and, in particular, allows significantly reducing the accumulation of dirt in the windrows.

According to the present invention, a star-wheel rake is provided as defined in1.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 1 to 3, a star-wheel rake according to one embodiment of the present invention is indicated by reference numeral1and comprises a frame2and a plurality of raking units3mounted side by side on the frame2.

In the example shown, the frame2comprises a support bar5and a drawbar6. The support bar5extends transversely in a travel direction D of the rake1in the working configuration and supports the raking units3in a rotational manner.

The drawbar6has a first end fastened to the support bar5and a second end fitted with a three-point hitch7for connection to a means of transport, for example a tractor8(partly and schematically shown only inFIG. 1). Furthermore, the drawbar6has an arc-like shape and extends above the raking units3.

In the embodiment shown here, the rake3is adapted to be carried by the tractor8and therefore it has no support wheels. Nevertheless, it is understood that the rake could still be towed, in which case the frame could be provided with one or more support wheels.

Each raking unit3comprises a front rake wheel10and a rear drive wheel11. It is understood that hereinafter the terms “front” and “rear” and their derivatives are with reference to the travel direction D in the working configuration. For example, the front end of the drawbar6carries the three-point hitch7, while the rear end is fastened to the support bar5.

The front rake wheels10may be conventional rake wheels (also known as star wheels). In particular, the front rake wheels10are substantially planar and are provided with respective outer rings of teeth10a, shaped so as to collect the forage and move it sideways during forward movement of the rake1.

The rear drive wheels11may be of the same type as the front rake wheels10, of a different size in the embodiment described and illustrated herein. In this case, in use, the teeth11aare in contact with the ground to set the rear drive wheels11in rotation when the rake proceeds in the travel direction D.

The front rake wheels10and the rear drive wheels11of the rake1are mounted on the frame2with respective parallel rotation axes.

The front rake wheel10and the rear drive wheel11of each raking unit3are coupled to each other such that the rotation of the rear drive wheel11, due to the effect of contact with the ground during forward movement, causes rotation of the front rake wheel10. Furthermore, the two wheels are arranged such that the front rake wheel10is raised when the rear drive wheel11is in contact with the ground.

In one embodiment, the front rake wheel10and the rear drive wheel11of each raking unit3(except for a raking unit3aplaced at a discharge side of the rake1) are coaxial and angularly fixed with respect to each other, even though idly mounted as a whole on the frame2. For example, the front rake wheel10and the rear drive wheel11are mounted on a same hub14, which is in turn fitted on a respective shaft15fastened to the frame2. Furthermore, the front rake wheel10has a smaller diameter D1than the diameter D2of the rear drive wheel11.

In the raking unit3aon the discharge side of the rake1, the front rake wheel10and the rear drive wheel11have respective parallel and separate rotation axes. In particular, the rotation axis of the rear drive wheel11of the raking unit3ais offset with respect to the rotation axis of the front rake wheel10and displaced towards the adjacent raking unit3. In practice, with respect to a direction of flow of the processed forage, the rotation axis of the rear drive wheel11of the raking unit3ais displaced upstream with respect to the rotation axis of the front rake wheel10. In one embodiment, the connection between the front rake wheel10and the rear drive wheel11of the raking unit3ais obtained by a double cardan joint12. Alternatively, it is possible to use other transmission means, such as a crown and pinion coupling or a belt coupling. Furthermore, the rear drive wheel11of the raking unit3ais arranged at the rear of the support bar5of the frame2, while all the other wheels10,11are arranged at the front. In a different embodiment, not shown, the rear drive wheels11of all the raking unit3aare arranged at the rear of the support bar5of the frame2.

The rotation axes of the front rake wheels10and of the rear drive wheels11are parallel to each other and oblique with respect to the travel direction D of the rake1in the working configuration. The front rake wheels10are arranged side by side and partially overall each other and define a working front, between the discharge side (where raking unit3ais positioned) and an upstream side opposite to the discharge side, and a flow direction F along the working front from the upstream side towards the discharge side. The rake wheels10that are more upstream with respect to the flow direction F are arranged in front of rake wheels10immediately downstream, so as to facilitate collection of the forage.

In one embodiment in particular, the front rake wheel10of each raking unit3has a respective portion interposed between the front rake wheel10and the rear drive wheel11of the respective adjacent upstream raking unit3. Similarly, the rear drive wheel11of each raking unit3has a respective portion interposed between the front rake wheel10and the rear drive wheel11of the respective adjacent downstream raking unit3.

In use, the rake1is connected to the tractor8via a three-point hitch7and is carried at a height such that the rear drive wheels11of the raking units3are in contact with the ground. The rear drive wheels11rotate due to the combined effect of moving forward in the travel direction D and of contact with the ground, causing the respective front rake wheels10to be driven in rotation. The forage is collected by the front rake wheels10along the working front and moved along the flow direction F to the discharge side, where a windrow is formed. The front rake wheels10, having a smaller diameter with respect to the rear drive wheels11, are raised above the ground and do not raise dirt when working. Obviously, the contact of the rear drive wheels11with the ground raises dirt and soil, which however cannot mix with the forage transferred by the front rake wheels10due to the forward movement of the rake1in the direction of travel. Furthermore, the rear drive wheel11of the raking unit3ais offset towards the inside of the working front with respect to the corresponding front rake wheel10and can discharge the dirt at a certain distance from the windrow without mixing it with the forage.

The rake1thus has the advantages of star-wheel rakes (in particular the simple structure and low costs) and, in addition, enables drastically reducing contamination of the forage with dust, soil and other dirt.

The fact of having separate wheels for driving force and for forage collection also allows greater freedom in the design of the rake. For example, the rear drive wheels could have different characteristics with respect to the front rake wheels and be specifically designed to improve rolling and reduce dust cloud formation. The front rake wheels could instead be optimized for the collection and transfer of forage.

FIG. 3shows a raking unit103of a star-wheel rake according to a different embodiment of the invention. The raking unit103comprises a front rake wheel110and a rear drive wheel111, which are coaxial and are coupled to each other so that the rotation of the rear drive wheel111, due to the effect of contact with the ground during forward movement, causes rotation of the front rake wheel110. In this case, the front rake wheel110and the rear drive wheel111are connected to each other by a coaxial speed reducer112(only shown schematically) and can therefore rotate at different speeds.

FIG. 4shows a raking unit203of a star-wheel rake according to a further embodiment of the invention. The raking unit203comprises a front rake wheel210and a rear drive wheel211having respective parallel and separate rotation axes A1and A2. In particular, in the working configuration, the rotation axis A1of the front rake wheel210is higher off the ground with respect to the rotation axis A2of the rear drive wheel211. The front rake wheel210and the rear drive wheel211are also coupled by cogwheels212and213fixed to respective hubs. In an alternative embodiment, not shown, the connection may be implemented by drive belts. The front rake wheel210is set in rotation by the rotation of the rear drive wheel211, in turn caused by movement along the direction of travel and from contact with the ground. In this case, the front rake wheel210can have the same diameter as the rear drive wheel211or one even slightly larger.

According to the embodiment shown inFIG. 5, a star-wheel rake300comprises a frame302and a single raking unit303that includes a plurality of front rake wheels310coupled to a same rear drive wheel311. The front rake wheels310and the rear drive wheel311are mounted on the frame302with respective parallel rotation axes. The front rake wheels310and the rear drive wheel311are arranged such that the front rake wheels310are raised when the rear drive wheel311is in contact with the ground.

Furthermore, the front rake wheels310are coupled to the rear drive wheel311such that the rotation of the rear drive wheel311, due to the effect of contact with the ground during forward movement, causes rotation of all the front rake wheels310of the raking unit303. In one embodiment in particular, the rear drive wheel311is rigidly coupled to one of the front rake wheels310and the front rake wheels310are coupled to each other, for example by drive belts312. Advantageously, the front rake wheel310rigidly coupled to the rear drive wheel311is not the one positioned on the discharge side of the rake300, to avoid contamination of the forage collected in the windrow. However, in an embodiment not shown, the rear drive wheel can transmit drive to the front rake wheel on the discharge side by drive members that allow offsetting the rotation axes, so that the rear drive wheel can be distanced from the discharge side, as in the raking unit3ainFIG. 1. Also in this case, the connection between the rear drive wheel and the front rake wheel may be obtained, for example, by a double cardan joint, crown and pinion coupling or a belt coupling.

In an embodiment that is not shown, a star-wheel rake may comprise a plurality of raking units arranged side by side to form a working front and each having a plurality of front rake wheels (for example, two or three) coupled to a same rear drive wheel.

FIG. 6shows a multiple rake400that comprises a plurality of star-wheel rakes401, substantially of the type already described, which are connected to each other. In particular, each rake401comprises a frame402and raking units403mounted on the frame402. The raking units403each comprise a front rake wheel410and a rear drive wheel411. The frames402are rigidly connected to each other and supported by wheels406. A common three-point hitch407(or, in alternative, a tow hitch, not shown) enables connection to a tractor408.

Finally, it is clear that modifications and variants can be made to the described rake, without departing from the scope of the present invention, as defined in the appended claims.