Device for gripping a stalk of a plant cut off by a harvesting machine, for further processing

The invention relates to a device for gripping a stalk of a plant cut off by a harvesting machine, for further processing, which harvesting machine comprises a cutting element for cutting off said stalk just above the ground. More particularly, the invention relates to a device for feeding a stalk of a Brussels sprout plant which has been cut off by the cutting element of the harvesting machine into a picking head.

Machines for harvesting Brussels sprouts are known, the stalk of the Brussels sprout plant being cut off close to the ground, after which said stalk is gripped by an operative and fed horizontally, cut end first, into the picking head. Said picking head, which is of a known type, comprises a number of rotating cutters, which bound a feed aperture and cut off the Brussels sprouts present along the stalk. A number of defoliation rollers are usually also disposed at some distance in front of the picking head, which rollers bound a throughput aperture which is clearly larger than the feed aperture of the picking head. Said rollers, which rotate in the opposite direction to the direction of feed of the stalk, serve to remove the leaves from the stalk.

It will be clear that feeding in the stalks by hand is hard and unpleasant work, which also has to be carried out at a cold time of year. The actions to be performed are complicated, since the cut-off stalk has to be lifted up, turned to the horizontal position and then guided with the cut-off end accurately along the defoliation rollers into the picking head. This, combined with the irregular shape of the stalks, is probably the reason why no devices by means of which the cut-off stalks can be fed automatically into the picking head have been known until now.

The object of the invention then is to provide a device by means of which a cut-off stalk can be gripped efficiently and reliably for further processing.

This object is achieved according to the invention by means of a device which has the features specified in Claim 1. After being cut off by the cutting element of the harvesting machine, the stalk of the Brussels sprout plant is seized by the two grippers of the arm, one gripper gripping the stalk close to the cut-off end, and the stalk can be moved for further processing by moving the arm.

If the harvesting machine is provided with a processing element which has a feed aperture, the device according to the invention preferably has the features specified in Claim 2. The stalk is accurately guided in line with the axis of the feed aperture by grippers on the arm, is taken over by the feed element, and is then guided into the feed aperture of the processing element. During the infeed, the arm moves back again to the initial position, in order to pick up the next stalk. In this way the infeed of the stalk occurs in two successive steps, slightly overlapping each other, so that the speed of the cycle is increased.

According to the invention, the grippers which grip the stalk close to its cut-off end have sharp cutting edges on the sides of the jaws facing each other. This means that these jaws cut slightly into the softer parts of the stalk, in which case any side stems or leaves are severed, so that the grippers centre themselves around the harder core of the stalk, and correct positioning of the stalk in the gripper is always ensured. This is very important for the cut-off end of the stalk, in order to guide it accurately into the feed aperture of the processing element.

Other functional details and further developments of the invention emerge from Claims 5-9.

The invention is explained in greater detail with reference to the appended drawing, which illustrates a preferred embodiment of the device according to the invention, in which:

Figure 1

is a diagrammatic side view of the device according to the invention, which is fitted on a partially illustrated harvesting machine for Brussels sprouts;

Figure 2

is a section along the line II-II in Figure 1;

Figure 3

a is a section along the line III-III in Figure 1, with the gripper in the closed position for feeding in the stalk; and

Figure 3b

is a section along the line III-III in Figure 1, with the gripper in the open, returning position.

Figure 1 shows the device according to the invention for use in the case of a harvesting machine for Brussels sprouts, which harvesting machine is only partially shown. The harvesting machine for Brussels sprouts comprises a picking head 1, which is known per se and has a number of rotating cutters which bound a feed aperture having a horizontal central axis 2. A number of defoliation rollers 3 are fitted around the above mentioned axis 2 at some distance in front of the picking head, which rollers bound a throughput aperture for the stalk which is significantly larger than the feed aperture of the picking head. A conveyor belt 4, which removes the Brussels sprouts cut off by the picking head, is provided below the picking head. Throughput means 5 are also present behind the picking head, which throughput means pull the stalk fed into the picking head further through the latter. Another visible part of the harvesting machine for Brussels sprouts is a cutting element 6, formed by a shoe 7 which is situated near the ground and in which a circular saw 8 is present for cutting off the stalk. The harvesting machine described so far is conventional and moves to the left in the drawing, in the direction of travel indicated by the arrow P.

The device according to the invention is added to this conventional harvesting machine, in order to feed the cut-off Brussels sprout stalks into the feed aperture of the picking head, an activity which until now was carried out manually by an operative.

The device according to the invention is composed substantially of two parts, each carrying out one step of the two-step operation. The first step consists of gripping the stalk cut off by the cutting element 6 of the harvesting machine, and the alignment of said stalk with the axis of the feed aperture of the picking head. The second step consists of accurately guiding the stalk into the feed aperture.

The part of the device according to the invention for carrying out the first step is composed of a two-legged arm 10, which has a long leg 10a and a short leg 10b situated perpendicular thereto. The short leg 10b is immovably connected to a shaft 11, which runs parallel to the long leg 10a and is rotatably mounted in a housing 12. By means of the shaft 11, the arm 10 is thus rotatably attached to the housing 12. The housing 12 itself is mounted in such a way that it can tilt about a fixed shaft 13, which is situated perpendicular to the rotary shaft 11 and in Figure 1 perpendicular to the plane of drawing. A bevel gear transmission (not shown in any further detail) is provided between the fixed shaft 13 and the rotary shaft 11, said gear transmission having such a transmission ratio, that when the housing is tilted through 90° relative to the fixed shaft 13, the shaft 11, and thus the arm 10, is rotated through 180°. The tilting of the housing 12 about the fixed shaft 13 is achieved by means of a rod 14, which on one side is hinged to the housing 12 and on the other side is hinged to a crank mechanism 15. The entire construction is made in such a way that when the crank mechanism 15 is rotated anticlockwise through 180°, the housing 12 tilts through 90° in the plane of drawing and takes the arm 10 with it. At the same time, the shaft 11, and consequently the entire arm 10, is rotated through 180° by way of the bevel gear transmission. The arm 10 then assumes the position indicated by dashed lines in Figure 1.

Figure 1 shows the arm 10 in the initial position for carrying out the cycle of the first step, i.e. the long leg 10a is in a vertical position and ends near the shoe 7 of the cutting element 6. Two grippers are provided along the long leg, on the front side of said leg, viewed in the direction of travel P, namely a first, bottom gripper 16, which is situated near the free end of the long leg 10a directly above the circular saw 8, and a second gripper 17, which is situated some distance above the bottom gripper along the long leg. The two grippers are fixed to operating rods 18, 19, which are provided along the long leg 10a, and which are rotated by means of piston-cylinder units 20, 21, with the aid of which the grippers are operated in order to open and close said grippers.

Figure 2 shows the bottom gripper in its closed position. A stalk 22 is also clamped in this gripper, which stalk was cut off by the circular saw 8 a short time beforehand. As can be seen in this figure, the gripper 16 has cutter-like jaws, i.e. the sides 16' of the jaws which face each other are designed with sharp cutting edges. This has the advantage that said cutting edges penetrate into the relatively softer parts of the stalk during closure of the gripper, any side stems, leaves or other soft parts being severed. In this way the gripper centres itself around the relatively harder core of the stalk, so that clear positioning of the stalk in the gripper 16 is ensured, which positioning is of great importance during further processing of the above mentioned stalk.

The other gripper, situated some distance above the bottom gripper, is a different shape and clamps the stalk by, as it were, clasping it without penetrating into it.

As described above, the stalk cut off by the circular saw 8 is seized by the two grippers 16, 17, after which the arm 10 is tilted by means of the crank mechanism 15 and rotated into the position indicated by dashed lines, the long leg 10a running horizontally and the axis of the clamped stalk substantially coinciding with the axis 2 of the feed aperture of the picking head 1. In this position, the stalk is taken over by the second part of the device described below, in order to carry out the second step of the operation.

The second part of the device according to the invention for carrying out the second step is formed by a feed element, indicated in its entirety by the reference numeral 29, which comprises two grippers 30, 31, each fixed by means of a slide 32, 33 on a horizontal guide bar 34. Each slide is in turn connected to a piston-cylinder unit 35, 36, by means of which the slides, and thus the grippers, can be moved along the guide bar 34. The two piston-cylinder units 35 and 36 are connected to each other in series, so that the two grippers can move together from the initial position towards the feed aperture. In addition, each slide is further provided with a piston-cylinder unit 37, 38 for opening and closing the respective grippers.

In Figure 1 the two grippers 30, 31 are shown in the initial position, in which the stalk is taken over from the grippers 16, 17 of the arm 10. In this case the gripper 30 is situated immediately to the right of and next to the gripper 17 of the arm, while the gripper 31 is situated immediately to the right of and next to the gripper 16 of the arm. The grippers 30 and 17 are of the same type, i.e. they grip around the stalk. The grippers 16 and 31 are likewise of the same type, i.e. their jaws have sharp cutting edges, which penetrate into the relatively softer parts of the stalk, for correct positioning of the stalk in the gripper. As soon as the grippers 30 and 31 have taken over the stalk, the arm 10 returns to the initial position in order to pick up the next stalk by means of the grippers 16 and 17.

The way in which the stalk is fed into the picking head will now be described with reference to Figures 3a and 3b. Figure 3a shows the picking head 1 with the defoliation rollers 3 present in front of it. The gripper 31 in this case is in the closed position, in which a stalk 22 is clamped. Said gripper likewise has sharp cutting edges 31', in order to position the stalk accurately relative to it.

In this figure it can be seen clearly that an aperture for allowing through the closed gripper is left clear between the defoliation rollers. In other words, the top defoliation roller is left out here, in order to make it possible for the gripper 31 to go within a few millimetres of the picking head, so that the stalk can be guided reliably into the feed aperture. From the position shown in Figure 1, in which the stalk has been taken over from the grippers 16 and 17, the two grippers 30 and 31 move together to the right, in such a way that the gripper 31 passes the defoliation rollers 3, until the gripper 31 guides the cut-off end of the stalk into the feed aperture of the picking head. At this moment the gripper 31 lets go, while the gripper 30 presses the stalk further into the picking head until the stalk is pulled further through the picking head by the throughput means 5. When the gripper 31 lets go, it spreads out fully, so that the arms of the gripper are situated substantially in line with each other. This position is shown in Figure 3b. When the gripper 31 has fed the cut-off end of the stalk into the feed aperture, said gripper cannot move back along the same path, because the stalk which has not yet been fully put through impedes the return trip. By spreading the gripper 31 so far, it is ensured that said gripper can move back to the initial position over the defoliation rollers. The two grippers can consequently move back together to the initial position without having to wait until the stalk has been fed fully into the picking head by the throughput means 5. The cycle time of this second step is shortened in this way.

The device is also provided in the usual manner with the necessary hydraulic, pneumatic or electric operating and/or control devices, which need not be described any further here.

An important characteristic of the device according to the invention is that the stalk is gripped near the cut-off end immediately after it has been cut off and is positioned accurately relative to said gripper. This makes it possible to feed said cut-off end accurately and reliably into the feed aperture of the picking head, irrespective of the further shape or size of the stalk.

It will also be clear that the invention is not restricted to the device illustrated and described here, but that for the person skilled in the art a large number of variants and modifications are possible within the scope of the appended claims, depending on the nature of the stalks to be processed and the harvesting machine used.