Cutting device
The invention relates to a cutting device for cutting objects, for instance agricultural crops such as carrots, courgettes, rettich, leeks or the like.
Known are cutting devices for for instance carrots, with which the ends of carrots are cut off, and the carrots are subsequently cut into pieces or chunks of approximately equal length.
A known problem with such devices is to cut the ends uniformly and straight. A solution used is to guide the carrots past cutting means by means of a conveyor belt provided with walls transverse to the conveyor belt. The carrots are brought to the side/edge? of the conveyor belt against a stop at a certain distance from the side of the conveyor belt, and are subsequently cut off between the belt and the stop. To for instance move carrots over the latitudinal direction of the conveyor belt against the stop it is known to position the conveyor belt inclined and to make the entire conveyor belt vibrate.
A drawback of said known device is that almost the entire cutting device is made to vibrate, and that the conveyor belt has to be positioned in an inclined manner which leads to a complex and vulnerable arrangement.
In US-A- 4.831 .925 a cutting device is described, provided with a conveying device having compartments. In two zones the compartments are
inclined. In said zones the compartments are shaken at one side whereas the centre is attached in a tiltable manner. A drawback of this cutting device is that a large load arises of the tilting points. Additionally the inclined transport of the compartments leads to a complex and vulnerable arrangement.
In FR-A-2.579.922 a cutting device is shown having an inclined conveying device, provided with a vibration device which makes the conveying device vibrate in the plane of the conveyance direction. Here as well the draw- backs mentioned arise.
It is an object of the invention to at least partially overcome the drawbacks mentioned. Additionally it is an object of the invention to effect a processing speed that is as high as possible.
To that end the invention provides a cutting device for cutting objects for instance agricultural crops, such as carrots, comprising a supply device, a conveying device, for conveying the objects to be cut in a con- veyance direction, the conveying device being provided with compartments provided with a bottom, which are almost open to the sides, and which are connected one to the other, the compartments having a longitudinal axis, almost perpendicular to the conveyance direction, which longitudinal axis is almost horizontal, - first cutting means positioned with a cutting plane along the side of the conveyor device, a first stop next to the compartments along the cutting plane and substantially parallel thereto, the cutting plane being situated between the side of the conveyor device and the stop, and - shaking means arranged before the cutting means, and adapted for locally, over a first shaking track, causing a shaking movement of the conveyor device with an accelerated movement oblique to the
bottom of the compartments, out of the plane of the bottom of the compartments and out of the plane described by the conveyance direction and the normal of the bottom of the compartments.
By choosing a conveyor device having compartments with a longitudinal axis that is almost horizontal and shaking means that locally make the conveyor device shake, a device is obtained that is simple and cheap to make and maintain, and which appears to be very operationally reliable. Because of the oblique accelerated movement a nett movement of the objects to be cut is created towards the side of the compartments against the stop.
Shaking as meant according to the inventions regards a short, quick shaking or vibrating movement.
It should of course be clear that the longitudinal axis of the compartments may be indeed inclined a little. As a result of the shaking means this is not necessary however, and it is preferred, particularly in connection with wear and tear and speed, that the longitudinal axis is practically horizontal.
The conveyor belt is locally, particularly over a certain, limited length of the conveyor belt, a shaking track, made to shake. As a result it has appeared possible to use a simple commercially available conveyor belt with compartments. In an embodiment the conveyor means comprise a conveyor belt, preferably a continuous conveyor belt, having separating means regularly spaced apart and transverse to the conveyor belt such that as a result continuous elongated compartments are formed widthwise, preferably almost as wide as the conveyor belt, the first stop being arranged outside of next to the conveyor belt along the cutting plane and substantially parallel thereto, the cutting plane being situated between the side of the conveyor belt and the stop.
The cutting device appears to be particularly suitable for removing the ends from agricultural products such as for instance carrots.
When operative, an embodiment of the conveyor device is adapted to let either the bottoms of the compartments or the conveyor belt at the location where either the conveyor belt or the compartments are/is shaken travel an almost horizontal track. Because the conveyor belt travels an almost horizontal track, hardly any disadvantageous effects arise on the belt.
Preferably the shaking means are adapted for causing a movement of the side of the conveyor belt substantially upwards or downwards, starting from a position of equilibrium of the conveyor belt.
It has appeared advantageous here that the shaking means are adapted to carry out the either upward or downward movement in an accelerated manner. As a result the objects that have to be moved are efficiently brought into motion.
It is preferred that the shaking means are adapted for moving a side of the conveyor belt substantially upwards or downwards with respect to the position of equilibrium of the conveyor belt.
A possible realisation is one in which the shaking means are adapted for moving the conveyor belt either upwards or downwards from the position of equilibrium and subsequently bringing it back into the position of equilibrium.
The best results, that means quick and reliable movement of the products, are nonetheless obtained by means of shaking means adapted for locally shaking the conveyor belt, as a result of which the conveyor belt carries out an elliptic movement almost perpendicular to the conveyance direction.
Very suitable as well is a periodical movement along a line out of the plane of the conveyor belt and which line is at an angle to the conveyance direction.
The movement is fast, preferably having a frequency of 500-2000 vibrations a minute, specifically approximately 1 100-1 500 vibrations a minute. In order not to burden the conveyor belt too heavily the amplitude of the movements is very small, hardly visible to the eye. Preferably the amplitude is approximately 1 cm at a maximum, more preferably 0.01 -0.2 cm at a maximum.
More particularly a possible realisation is one in which the shaking means are adapted for exerting a shaking movement as a result of which the conveyor belt, considered in conveyance direction, describes an elliptic course to the main axis in an angle smaller than 90 degrees to the surface of the conveyor belt. In practice the angle will approximately be 30-60 degrees.
A possibility for realising the shaking movement described above and which is preferred, is to provide the shaking means with a shaking frame underneath the conveyor belt and to provide the shaking frame with at least one imbalance motor. In this way shaking means, of which the shaking movements are accurately adjustable, can be realised in a cheap and simple and operationally reliable manner. Preferably the shaking frame is provided with two imbalance motors, one on each side. Preferably the imbalance motors rotate oppositely, and preferably 1 80 degrees out of phase in order to eliminate undesired shaking. The imbalance motors are positioned such that the rotation axis is at an angle to the normal of the conveyor belt and at an angle to the plane defined by the normal of the conveyor belt and the conveyance direction. As a result it is possible to realise a shaking movement with a displacing component. Imbalance motors are known per se, and are built up from electro motors provided with eccentric weights on the axis of rotation. Another possibility to realise
the shaking means is using the means and drive that are also used in a so- called eccentric sieve, or means that drive a vibrating sieve moving products to one side. In such sieves products are moved in a conveyance direction by the shaking movement.
For the sake of firmness it is preferred that the shaking means comprise a box underneath the conveyor belt, which box is provided with imbalance motors.
In order to transfer the shaking movement well and efficiently to the conveyor belt, it is preferred that the cutting device is further provided with connection means for retaining the conveyor belt on the shaking means. Preferably the connection means are adjustable and can be switched on and off.
A simple realisation for the connection means is this one, in which the connection means comprise vacuum elements for causing a vacuum underneath the conveyor belt. An alternative is for instance providing the conveyor belt with iron strips or parts, and to mount electro magnets on the shaking means as a result of which the conveyor belt is secured to the shaking means because of the magnetic force.
In order to realise a good contact between the conveyor belt and the shaking means, in an embodiment the connection means comprise a chamber underneath the conveyor belt at the location of the shaking means, of which chamber the side facing the conveyor belt is air permeable. In an embodiment the chamber is integrated in the shaking frame or is a part of it. The shaking frame can for instance be designed like a box which in its entirety forms the vacuum chamber. The top side, i.e. the side over which the conveyor belt runs, may be provided with holes. By now realising an under pressure or a vacuum by means of known means, such as a pump, or even simpler, a common household or industrial vacuum
cleaner, the conveyor belt is pulled against the shaking frame and the movement of the shaking frame is transferred to the conveyor belt. It additionally is a solution that is simple to realise when the chamber is connected to an apparatus for ensuring a vacuum, preferably a pump, by means of a flexible hose. To make the action of the vacuum run efficiently it is preferred that the conveyor belt is substantially closed. A closed PVC conveyor belt provided with partitions transverse to the belt is very suitable. Preferably the conveyor belt is, in short, a belt made of synthetic material, in an embodiment provided with upright walls perpendicular to the longitudinal direction of the conveyor belt.
In order to move the products on the conveyor belt to the other side of the conveyor belt, use can be made of second shaking means spaced apart from the first shaking means. After the second shaking means the cutting device can be provided with second cutting means beyond the second shaking means. As a result both ends of the products are cut off.
It has appeared possible to build a compact device and having a large processing capacity by providing the cutting device according to the invention with a second conveyor device, such as a conveyor belt, substantially parallel to the first conveyor device, in which the shaking frame or shaking frames extend underneath both conveyor devices. As a result two shaking means will suffice. The drive of the shaking means, the imbalance motors, in an embodiment are then arranged between the conveyor devices.
In an embodiment, cutting takes place by means of a water jet knife or water jet knives. To that end very thin water jets under high pressure are being used. An advantage is that the products are cut off straight. In the already mentioned FR-A-2.579.922 water jet knives are mentioned in general, it being noted however that they give rise to problems. In the cutting device according to the invention they can however be deployed to
great advantage in connection with the further simple arrangement. In US- A-5.927.320 suitable water jet knives are for instance discussed. It may also be possible to use disk-shaped rotating knives or saw blades that move up and down.
Additionally the application relates to a device for moving objects by means of a conveyor belt in a conveyance direction in a conveyance plane wherein the objects are also moved to the side of the conveyor belt, in which the conveyor belt is provided with shaking means adapted for locally shaking the conveyor belt with a shaking movement out of the plane of the conveyor belt, the entire conveyor belt being locally moved out of the conveyance plane.
As a result it appeared possible to relatively easily move objects on a conveyor belt, transversally with respect to the conveyance direction, without having to make the entire device vibrate or positioning the belt inclined.
Additionally the invention also relates to a method for cutting agricultural products, particularly carrots, in which the agricultural products are brought onto a conveyor belt having compartments that are open on the side, the conveyor belt is guided along a horizontal area where the conveyor belt is brought into a shaking movement in which one side of the conveyor belt is either periodically brought upwards or one side is periodically brought downwards or that the conveyor belt, substantially perpendicular to the conveyance direction, describes an elliptic course with the main axis at an angle to the plane of the conveyor belt, so that the agricultural products are moved to one side of the conveyor belt against a stop situated at the one side adjacent to the conveyor belt and subse- quently a portion of the agricultural products that protrudes beyond the conveyor belt is cut off.
Because of the shaking of the belt in a specific manner it has appeared possible to cut off for instance the ends of agricultural products, in a simple manner. Said agricultural products may for instance be carrots, but also leeks, rettich, oyster plants, asparagus, or other agricultural products that may or may not be elongated.
Additionally the invention relates to a cutting device for for instance agricultural crops such as carrots, comprising a supply device, - a conveying device, provided with a conveyor belt having separating means, regularly spaced apart and transverse to the conveyor belt, such that as a result continuous elongated compartments are formed widthwise, first cutting means positioned with a cutting plane along the side of the conveyor belt, a first stop outside of the conveyor belt along the cutting plane and substantially parallel thereto, the cutting plane being situated between the side of the conveyor belt and the stop, and shaking means for shaking the conveyor belt, arranged before the cutting means, and adapted for locally causing a shaking movement of the conveyor belt, in which the shaking means comprise vibration means positioned at an angle to the normal of the conveyor belt, the conveyor belt at the location of the shaking movements running in a horizontal plane.
Additionally the invention relates to a cutting device for for instance agricultural crops such as carrots, comprising a supply device, a conveying device, provided with a conveyor belt having separating means, regularly spaced apart and transverse to the conveyor belt, such that as a result continuous elongated compartments are formed widthwise,
first cutting means positioned with a cutting plane along the side of the conveyor belt, a first stop outside of the conveyor belt along the cutting plane and substantially parallel thereto, the cutting plane being situated be- tween the side of the conveyor belt and the stop, and shaking means for shaking the conveyor belt, arranged before the cutting means, and adapted for locally causing a vibration of the conveyor belt, obliquely to the plane of the conveyor belt and substantially perpendicular to the conveyance direction, the con- veyor belt at the location of the vibration running in a horizontal plane.
The invention is further elucidated on the basis of an exemplary embodiment of a device according to the invention, in which:
Figure 1 shows a top view of an exemplary embodiment of a cutting device according to the invention;
Figure 2 shows a side view of the cutting device of figure 1 ;
Figure 3 shows a side view of the shaking means partially in cross-section;
Figure 3A shows the shaking direction of the shaking means of figure 3;
Figure 4 shows a side view of the second shaking means, partially in cross-section;
Figure 4A shows the shaking direction of the second shaking means of figure 4 and
Figure 5 is a rear view of the cutting device of figure 1
Figure 1 shows a top view of a cutting device 1 according to the invention for the cutting of, in this case, carrots 2. The device is provided with two conveyor belts 3, 3' that are parallel one to the other and provided with upright walls 4 transverse to the conveyor belt as a result of which com- partments 5 are formed that are open at the sides. Such a conveyor belt is also called pocket conveyor. The conveyor belt is confined at the sides and is positioned substantially horizontally and flat.
By means of a supply device 6 carrots 2 are brought onto the conveyor belt 3, 3' in the compartments 5. The cutting device 1 is further provided with a shaking frame 8 or box provided with first shaking means 7 which frame or box runs underneath the two belts and also a shaking frame 8 or box comprising second shaking means 7' which frame or. box runs underneath the two belts a little further in conveyance direction of the conveyor belts. Both shaking frames 8 are each on both sides and between the conveyor belts provided with imbalance motors 9, 9', 9", 9'". Such imbalance motors are known to the expert. The imbalance motors are provided with adjustable weights with which the amplitude of the shaking is adjustable.
Both shaking frames are internally provided with vacuum chambers (not shown in this figure, see figure 2), at the upper side underneath the conveyor belts. The vacuum chambers are provided with holes 10 in the vacuum chamber at the side of the conveyor belts (so not in the conveyor belts!).
Furthermore two first water jet knives 1 1 , 1 1 ' and two second water jet knives 21 , 21 ' are shown in the figure, after each shaking frame at different sides of the conveyor belt. Before each water jet knife a stop 1 2, 12', 12", 12'" has been arranged adjacent to the conveyor belt.
Additionally the cutting device 1 of figure 1 has been provided with disk-
shaped knives 13 for cutting the carrots into pieces or chunks.
The cutting device can be divided into a first area I, a second area II where shaking means are provided (first shaking track) and the products to be cut are moved to a first side, a third area III, a fourth area IV where the products are moved to the other side (second shaking area), and a fifth area V, where in this example the products are cut into pieces or chunks.
The operation of the cutting device 1 is as follows. The carrots 2 are supplied via the supply device 6 (only the lowermost conveyor belt 31 is shown in the figure) and end up in the compartments 5. The conveyor belts 3, 3' run in conveyance direction B over the shaking means 7, 7'.
The carrots 2 are moved to the one side of the conveyor belt 3, 3' by the shaking means 7, where they run into stops 12, 12". The carrots are now are positioned with their ends adjacent to and beyond the conveyor belts
3, 3'. By means of the two first water jet knives 1 1 and 1 1 ' the ends are cut off on one side of the carrots.
Subsequently the conveyor belts 3, 3' run further over the second shaking means 7' where the carrots are moved to the other side of the conveyor belts 3, 3' where they run into the stops 12', 12'" and where by means of the second water jet knives 21 , 21 ' the other ends of the carrots are cut off. The conveyor belts 3, 3' subsequently run further past the parallel (disk-shaped) knives 13 where the carrots are cut into pieces or chunks.
Figure 2 shows a side view of the device of figure 1 according to the invention. It can be seen that the supply device 6 is formed by a trough through which the carrots 2 slide in an oblique position and end up in the compartments 5. The conveyor belt 3 runs further via a conveyance plane T. The conveyor belt 3 is endless.
It can be seen in the figure that the shaking means 7, 7' comprise box-
shaped shaking frames 8. The shaking frames 8 are shown in cross- section. The imbalance motors are not shown in this figure. At their upper side, the box-shaped shaking frames 8 are provided with vacuum chambers 1 5 that are provided with holes 10 at the upper side over which the conveyor belt 3 runs. By creating a vacuum in said vacuum chambers 1 5 the conveyor belt 3 is sucked onto the box-shaped shaking frames 8 as a result of which the shaking of the shaking frames 8 is transferred to the conveyor belt 3. As a result there is sufficient contact between the conveyor belt 3 and the shaking means 7, 7' to move the carrots to the one and the other side of the conveyor belt. In practice the necessary amplitude of the shaking is so little that it is hardly visible to the eye. A hand though, can feel that the conveyor belt is shaking. The frequency with which the conveyor belt is shaking in the embodiment is adjusted to approximately 1400 cycles or revolutions a minute. The conveyor belt is enclosed in between upright edges.
It can further be seen in the figure that the knives for cutting the carrots into chunks consist of disk-shaped knives 13.
Figure 3 shows a cross-section of the box-shaped shaking frame 8 of the shaking means 7. The box-shaped shaking frame 8 is arranged on shock absorbers 90, formed by rubber blocks, and on both sides provided with imbalance motors 30, 31 (cannot be seen behind imbalance motor 30). Said imbalance motors 30, 31 are known to the expert and either on one side or two sides provided with adjustable eccentric weights 32 on the rotation axis 33 as a result of which the amplitude of the shaking is adjustable. Because of the number of revolutions of the imbalance motors the frequency is adjustable. The imbalance motors 30, 31 (imbalance motor 31 behind imbalance motor 30 at the opposite side of the shaking frame 8) are positioned at an angle a, approximately 25-45 degrees. The conveyor belts
3, 3' run over the box-shaped shaking frame 8 and contact it. Said shaking means therefore move the carrots to the right.
In the box-shaped shaking frame 8 a vacuum chamber 15 is arranged which is provided with outlet openings or holes 10 towards the conveyor belts 3, 3'. At the bottom side the vacuum chambers 15 are provided with connections 16 to which an air pump or even a vacuum cleaner can be connected by means of a flexible hose (not shown).
In figure 3a the shaking direction 40 of the shaking means of figure 3 is shown. In practice the shaking means will carry out an elliptic movement in which the shaking direction indicated in figure 3a is the long axis of the ellipse. To prevent movement of the shaking means in the conveyance direction of the conveyor belts, imbalance motors with opposite rotation direction are attached on both sides of the shaking means. The imbalance motors will rotate almost 180 degrees out of phase. As a result all movements, except a resulting periodical movement oblique to the con- veyor belt and almost perpendicular to the conveyance direction, are compensated.
In figure 4 the shaking means 7' are shown for moving the carrots to the other side of the conveyor belts 3, 3' (figure 1 ). It can be seen that the imbalance motors are at an opposite angle, β, to the one in figure 3a. Said shaking means therefore move the carrots to the left.
In figure 4a the shaking direction 41 of the shaking means 7' of figure 4 is shown.
In figure 5 the cutting device of figure 1 is shown again, now in rear view and partially in cross-section. The imbalance motors 9 (and 9' that cannot be seen in the same angle) and 9'" (and 9" that cannot be seen either) of both shaking means are shown through each other.