WO1996013180A1

WO1996013180A1 - Vegetable trimming machine

Info

Publication number: WO1996013180A1
Application number: PCT/GB1995/002522
Authority: WO
Inventors: Jonathan King
Original assignee: Vatina Services Limited
Priority date: 1994-10-26
Filing date: 1995-10-26
Publication date: 1996-05-09
Also published as: GB2309156A; GB2309156B; GB9708211D0; AU3705595A

Abstract

A vegetable trimming machine comprising a movable cutting head having a pair of curved blades (2, 60) having co-operable cutting edges, the blades (2, 60) being mounted one within the other so as to be rotatable about a common axis (3), and means (7) being provided to rotate the blades (2, 60) between a cutting position in which the cutting edges of the blades (2, 60) overlap and a rest position in which the cutting edges are substantially angularly spaced apart. Vegetable heads are carried in cups (9) mounted on conveyor belt (10), and the vegetable trimming head is mounted on a reciprocating frame (20) which is mounted above the conveyor (10) and which moves the vegetable trimming head between a vegetable trimming position and a waste disposal position.

Description

VEGETABLE TRIMMING MACHINE Field of the Invention

This invention relates to a vegetable trimming machine for trimming off unwanted parts of vegetables, for example the stalk from cauliflower and calabrese (broccoli).

Background to the Invention

Vegetables such as calabrese and cauliflower are typically harvested as a head containing a body of stalk which, for many applications, for example for sup¬ ply frozen, needs to be trimmed off. This can be done manually, but at a prohibi- tive cost. Various machines have therefore been developed to carry out the trimming operation on a production-line basis.

In one known machine, a pair of shaped knives are moved obliquely to¬ wards each other to scoop out the centre of the vegetable head and then retracted to permit the operation to be repeated. This machine has several disadvantages. Firstly, the relatively slow oblique scooping action of the knives necessitates stop¬ ping the movement of the conveyor carrying the vegetable heads in cups fixed thereto while the cutting action takes place. This limits the speed of the machine and, if the synchronisation of movement is not perfect, poor trimming or damage to the cups and/or the knives can result. Further, the trimmed stalk material has to be separated from the desired product, the cauliflower or calabrese florets, by hand. Since the knives can move in a straight line oblique to the surface of the conveyor, the trimming action is not symmetrical, making it difficult to achieve an optimum shape of cut to minimise wastage.

Another approach has been to reciprocate the cutting knives so as to follow the movement of the conveyor cups while the trimming action is taking place. This permits a lower angle of cut, which is preferred since it does not leave sharp edges on the florets. Sharp edges, when frozen, can cause damage to packaging materials, as well as looking less attractive, and are therefore undesirable. Since each knife needs to be driven by its own pneumatic ram, however, the air con¬ sumption of the machine is high. The machine cannot readily accommodate dif¬ ferent sizes of vegetable head, and the resultant trimming is therefore necessarily a compromise. Accurate trimming is critical to the commercial success of such a ma¬ chine, since a small variation in the amount trimmed off the vegetable heads can substantially affect the value of the resulting product. If too much is trimmed off, the weight of the product may be smaller than it need be, and since the producer is paid according to the weight, money can be lost. Additionally, a greater weight of waste material (the trimmed off stalks) has to be disposed of, which can incur a fur¬ ther cost penalty. On the other hand, if too little is trimmed off, the customer may value the product less highly or even reject it. Summary of the Invention

According to the invention there is provided a vegetable trimming machine comprising a movable cutting head having a pair of curved blades having co- operable cutting edges, the blades being mounted one within the other so as to be rotatable about a common axis, and means being provided to rotate the blades be¬ tween a cutting position in which the cutting edges of the blades overlap and a rest position in which the cutting edges are substantially angularly spaced apart. Preferably, each blade generally conforms with a segment of a spherical sur¬ face, although they may be elliptical. The blades are preferably smooth-edged, but may be ridged or otherwise profiled so as to give a decorative cut. Preferably, while the blades extend over 180° in a plane through which the common axis extends, they occupy only a relatively small angle in a plane perpendicular to the common axis. In an alternative embodiment, the blades each occupy approximately a third of the surface of a sphere.

The blades are preferably rotated by means of a single actuator, for example a pneumatic ram, via a pair of pivoted links connected to extension arms extend¬ ing from the blades on the sides opposite to the cutting edges and around the spherical surface. Where the blades occupy substantially a third of the surface of the sphere, separate levers may be driven by separate actuators to rotate the blades into and out of the cutting position.

The cutting head is preferably mounted on a reciprocable frame above a moving belt carrying cups for receiving the vegetable material to be trimmed. The frame is arranged to bring the head down on to a cup to enable the head to per¬ form the trimming action and then lift it clear to a position in which the trimmed off matter can be deposited for disposal. The reciprocable frame may be mounted on a parallelogram frame driven by a means to generate reciprocating motion, which means may comprise reciprocating arms drivingly connected to a crank which is driven by suitable drive means, the said drive means being adapted to synchronise the motion of the cutting heads mounted on the reciprocating frame with the position of the means to receive the vegetable material to be trimmed. Preferably the drive means is the conveyor drive.

The operation of the cutting action of the blades is synchronised with the reciprocation of the reciprocable frame and the position of the means to receive the vegetable material to be trimmed by suitable means, such as switches activated by a cam linked to the conveyor drive.

Preferably at least one counter balance is attached by suitable connection means to the reciprocable frame so as to reduce the load on the reciprocating drive. The or each at least one counter balance is attached by the suitable connection means to a point on the reciprocable frame which counter balances any imbalance in weight of the reciprocable frame caused by the mounting of components such as the cutting means thereon.

A means to smooth the reciprocation of the reciprocable frame may be provided and may be a ram, such as an air ram, which acts upon the parallelogram frame. The machine may comprise mounting means to permit each cutting head to slide vertically, and means for sliding the head vertically up and down. A resil¬ ient mounting may be provided for the means for sliding the head vertically up and down. The mounting means preferably comprise a guide rail and at least one guide roller engageable thereon.

In a preferred form of the machine, means are provided for detecting the size of the vegetable material, for example a head of calabrese or cauliflower, and for adjusting the movement of the cutting head in accordance with the detected size to vary the cut achieved. Alternatively, or additionally, the machine may be provided with two cutting heads of different sizes, operable alternatively according to the detected size of the vegetable material. For example, if the material falls within a smaller first range of sizes, the smaller of the two cutting heads is caused to operate and the larger head is not operated, but if the material falls within a larger second range of sizes, the larger head is operated and the smaller head re¬ mains inactive. Since it is convenient to mount the two heads one behind the other relative to the movement of the conveyor carrying the vegetable material, timing means may be provided to vary the delay between the detection of the size and the operation of the cutting head. The detecting means may comprise a detec- tor arm which travels over the surface of the vegetable heads on the conveyor, the movement of the arm being translated into a control signal by means of a rheostat or discrete position sensors, for example. Alternatively, optical, ultrasonic or any suitable electronic detection means may be employed. The detection means may be arrange to measure the height of the vegetable head above the cup in which it is held, and / or the width of the vegetable head.

Each cutting head is preferably mounted so as to be vertically slidable, and means are provided for sliding the head up and down to bring it into and out of the position in which cutting takes place. Such means suitably takes the form of a pneumatic ram. In a preferred embodiment, two rams are used, connected in se¬ ries, the main ram giving the overall movement and the second ram providing an adjusting increment to vary the operating height of the cutting head selectively, preferably as a function of the vegetable size detected by the size detecting means. In an especially preferred embodiment, the second ram is in the form of a double- ended ram operable in differing increments at the opposite ends, in order to achieve a wider range of steps of adjustment. For example, one end may provide an extension of 5mm and the other end may provide an extension of 10mm, giv- ing, in combination, adjustment steps of 5, 10 and 15 mm. Different increments may be used, and more than one incremental double-ended ram may be used to give a wider variation or smaller increments over the same range. Alternatively, the increments may be provided by a single ram the extension of which is con¬ trolled by magnetic sensors which are connected to a suitable control means. In an alternative arrangement, in place of the incremental rams, individually-slidable shims may be used to limit the travel of the main ram in an incremental manner, movement of the shims being controlled by means of individ¬ ual actuators, for example pneumatic rams.

Other actuators than pneumatic rams may be employed to control the movement of the components of the cutting head. For example, electrical sole¬ noids may be suitable. Brief Description of the Drawings

In the drawings, which illustrate diagrammatically examples of the machine according to the invention: Figure 1 is a front elevation of the lower part of a cutting head, with the cutting blades in their closed position;

Figure 2 is a side elevation corresponding to Figure 1 ; Figure 3 is a side elevation showing the cutting blades partially open;

Figure 4 is a part-sectioned view showing the action of the cutting head on a vegetable head in a holding cup of a conveyor belt on the machine;

Figure 5 is a side view showing the mounting of the cutting head in relation to the conveyor;

Figure 6 is a side view showing the remainder of the reciprocating mounting of the cutting head;

Figure 7 shows a side view of an alternative design of cutting head; and

Figures 8 and 9 show side and front elevations respectively of the cutting head and mounting assembly according to an alternative embodiment of the invention. Detailed Description of the Illustrated Embodiments

Referring first to Figures 1 to 3, the cutting head comprises a pair of parallel side support arms 1 having a pair of cutting blades 2 rotatably mounted between them so that one is a close sliding fit within the other. Each of the blades 2 is semicircular when viewed from the front (Figure 1) and is mounted on common pivot pins 3 substantially along the diameter. Each blade 2 has a fixed arm 4 ex¬ tending from its centre point around substantially a quarter circle when viewed from the side (Figures 2 and 3), the arms 4 being on opposite sides of the blades 2. each arm 4 is connected to a central rod 5 extending vertically between the side support arms by a respective pivotal link 6, so that pulling on the central rod 5 draws the blades outwardly and upwardly away from each other, through the posi¬ tion illustrated in Figure 3 until they reach a maximum opening with each extend¬ ing substantially at 90° to the side support arms. The central rod is connected to a pneumatic ram 7 to permit the blades to be opened and closed rapidly to perform a trimming action and then to release the trimmed off stalk at the desired position, as hereinafter described. Figure 4 shows a head of calabrese 8 carried in a cup 9 attached to a con¬ veyor 10 forming part of the machine. The cutting head has been lowered on to the calabrese 8 with the blades in the fully-open position until the desired cutting depth has been reached, and the ram 7 has then been activated to rotate the blades through approximately 90° so that they slice uniformly through the calabrese, coming to rest at a position in which they overlap and support the cut¬ off stalk portion. It will be seen that the resultant spherical cut can be arranged to ensure that all florets within the calabrese head are cut off with a nearly straight cut, leaving no sharp edges of stalk. Figures 5 and 8 illustrate the mounting of the cutting head above the con¬ veyor 10 which carries the cups 9 for holding the vegetable heads during the trim¬ ming operation. A main transverse beam 11, described in more detail hereinafter with reference to Figure 6, mounts a carriage 12 to which are attached two pairs of vertically spaced apart guide rollers 14, each roller of a pair being horizontally spaced apart sufficiently to slidingly hold a guide rail 13 therebetween. Guide rail 13 is attached to one side of a vertical member 18, the other side of which is at¬ tached to the cutting head. A pair of vertical pneumatic rams 15 and 16 in series are mounted on the carriage 12 and act on an arm 17 extending from the cutting head to lift or lower the head relative to the carriage. The first ram 15 provides the greater part of the movement of the cutting head relative to the carriage, as herein¬ before described, while the second ram 16 is a double-ended ram giving two differ¬ ent increments of extension providing in combination four incremental height adjustment steps. The first ram 15 is resiliently mounted on carriage 12 by means a spring member 19. The beam 11 is arranged to move in a reciprocating arc move- ment, as described with reference to Figure 6 and as indicated by the arrow A, so as to be movable down on to the vegetable head 8 held in the cup 9 and, after clo¬ sure of the blades to cut the stalk from the vegetable head, retractable upwardly and forwardly of the machine relative to the direction of movement of the con¬ veyor 10, so as to lift the cut stalk away from the cup 9 and deposit it on a separate chute or conveyor 19 for disposal. At this position, the cutting head has been lifted fully relative to the beam 11 , and the blades are at their fully-open position to release the stalk. The trimmed vegetable product is discharged from the cups 9 at the end of the conveyor 10 into a receiving container.

Figure 6 shows the support structure for the beam 11. A main carrying frame 20 is mounted beneath the conveyor 10 and has three pairs of vertically- extending posts 21, 22 and 23, the front pair 21 of which carry the beam 11 , while the middle pair 22 carry a similar beam 24 which mounts a second cutting head. The beams 11 and 24 are carried on jacks permitting minor overall cutting height adjustments to be made, the jacks being operated simultaneously by means of a chain drive running between them (not shown).

The main carrying frame 20 is in turn mounted on a parallelogram frame arrangement 25 driven by reciprocating arms 26 from cranks 27 driven by the con¬ veyor drive so as to ensure that the motion of the cutting heads mounted on the frame 20 via the beams 11 and 24 is synchronised with the position of the cups 9 on the conveyor 10. Synchronisation of the operation of the ram 15 may readily be achieved by means of switches activated by a cam linked to the conveyor drive or by means of magnetic switches triggered by components of the drive. Other triggering means will be apparent to those skilled in the art.

A counter balance 50 is attached by means of a cable and pulley wheels to a point A on the carrying frame. The counter balance is approximately half the weight of the carrying frame 20. The carrying frame 20 is front heavy, indicated by arrow E, due to the position of the cutting heads on the carrying frame. By attach¬ ing the counter balance 50 via the cable at point A the weight indicated by arrow E can be counter balanced and the effective balance point of the carrying frame 20 brought back to point F. This reduces the load on the reciprocating drive mechanism.

The counter balance 50 slides up and down in a guide means which is fixed with respect to the reciprocating carrying frame 20, and which may take the form of a collar or the like.

Two of the described counter balances may be provided, one on each side of the machine.

An air ram 40, supplied at a pressure of approximately 25 psi, to smooth the reciprocating motion of the reciprocable carrying frame 20 is provided, and is attached at one of its ends to the parallelogram frame and at the other end to a plate 41 which is fixed with respect to the reciprocating carrying frame 20.

The size of the vegetable heads in the cups is detected by means of a sprung arm 28 which rides over the heads and is lifted according to the size. The arm 28, which is mounted on a beam extending between the posts 23, is provided with a damping cylinder 29 to prevent false indications through bouncing, and provides control signals by means of magnetic switches, micros witches, a rheostat, optical limit switches or the like, the control signals then controlling operation of the incremental height adjustment rams of the cutting heads, and/or selecting which of two different cutting heads is to be operated when a cutting head with larger cutting blades is mounted on the middle beam 24. Since the two cutting heads are spaced apart along the conveyor, the control signal will need to be elec¬ tronically timed to ensure that the appropriate cutting head is operated to trim the vegetable head to which the control signal relates.

While the cutting head hereinbefore described produces excellent results, the opening of the blades is limited to approximately 180°, and for some shapes and sizes of vegetable head, a wider opening is desirable. The cutting head illus¬ trated in Figure 7 permits an opening, in side view, of up to 240° by using two cutting blades 70 each of which is approximately a third of a spherical surface, piv- otally mounted between side arms 71, one of the blades 70 being fixed to the pivot pin 72, which is freely rotatable in the arm 71 and has a control arm 73 fixed to the outer end thereof. The control arm 73 is pivotally connected to a link 74 which is in turn connected to a pneumatic ram (not shown). The other blade 70 is freely rotatably mounted on the pin 72 and has a control arm 75 fixed thereto, the control arm 75 being linked to a respective pneumatic ram by a link 76. Retrac¬ tion of the pneumatic rams causes the blades to rotate to a position in which one lies substantially within the other, giving the 240° opening. Although the pneumatic rams in the embodiment as described are arranged vertically, it will be appreciated that horizontal rams mounted near to the control arms 73 and 75 may be used instead.

It can be seen from Figures 8 and 9 that the cutting head is comprised of two blades 60 each of which is approximately a quarter of a spherical surface and has a cutting edge 61. The blades co-operate to hold the portion of the cut stalk which, as previously described, is deposited in a separate chute or conveyor 19.

It will be appreciated that the machine may comprise several sets of cutting heads mounted side-by-side on the beams 11 and 24, with corresponding size detec¬ tors for each, so that several conveyors can be side-by-side, or a single conveyor having several sets of cups side-by-side, in order to maximise throughput of the machine, since it is possible for the operator to load the vegetable heads into the cups faster than a single cutting head can be operated to trim them.

The machine of the invention offers accurately-shaped cutting with a high degree of control, ensuring that the resulting product conforms closely with the de- sired specification with the minimum of wastage. It is envisaged that a machine in accordance with the invention may alternatively be mounted in the mobile har¬ vester so that the cut heads are trimmed immediately after separation from the plants, the waste being returned straight on to the field, to be ploughed in, for ex¬ ample, thus reducing the waste disposal problems.

Claims

1. A vegetable trimming machine comprising a movable cutting head having a pair of curved blades having co-operable cutting edges, the blades being mounted one within the other so as to be rotatable about a common axis, and means being provided to rotate the blades between a cutting position in which the cutting edges of the blades overlap and a rest position in which the cutting edges are substantially angularly spaced apart.

2. A vegetable trimming machine according to claim 1, wherein each blade conforms substantially with a segment of a spherical surface.

3. A vegetable trimming machine according to claim 1, wherein each blade is essentially elliptical.

4. A vegetable trimming machine according to any preceding claim, wherein the blades are essentially smooth-edged.

5. A vegetable trimming machine according to any one of claims 1 to 3, wherein the blades are profiled so as to give a decorative cut.

6. A vegetable trimming machine according to claim 5, wherein the pro¬ file of the blades is essentially ridged.

7. A vegetable trimming machine according to any preceding claim, wherein the blades extend over 180° in a plane through which the common axis extends while only occupying a relatively small angle in a plane perpendicular to the common axis.

8. A vegetable trimming machine according to any of claims 1 to 6, wherein the blades each occupy approximately a third of the surface of a sphere.

9. A vegetable trimming machine according to any preceding claim, wherein the blades are preferably rotated by of a actuator means.

10. A vegetable trimming machine according to claim 9, wherein the ac¬ tuator means comprises a single actuator, connected via pivoted links to extension arms extending from the blades on the sides opposite to the cutting edges.

11. A vegetable trimming machine according to claim 9, wherein the ac¬ tuator means comprises separate levers driven by separate actuators to rotate the blades in and out of the cutting position.

12. A vegetable trimming machine according to any preceding claim, wherein the cutting head is mounted on a reciprocable frame above a conveyor provided with means for receiving the vegetable material to be trimmed.

13. A vegetable trimming machine according to claim 12, wherein the frame is arranged to bring the cutting head down on to a means for receiving the vegetable material to be trimmed to enable the cutting head to perform the trim¬ ming action and then lift it clear to a position in which the trimmed off matter can be deposited for disposal.

14. A vegetable trimming machine according to claim 12 or 13, wherein the reciprocable frame is mounted on a parallelogram frame driven by means to generate reciprocating motion.

15. A vegetable trimming machine according to one of claims 12 to 14, wherein the means to generate reciprocating motion comprises reciprocating arms drivingly connected to a crank which is driven by a suitable drive means, the said drive means being adapted to synchronise the motion of the cutting heads mounted on the reciprocating frame with the position of the means to receive the vegetable material to be trimmed.

16. A vegetable trimming machine according to claims 15, wherein the drive means is the conveyor drive.

17. A vegetable trimming machine according to any of claims 12 to 16, wherein the operation of the cutting action of the blades is synchronised with the reciprocation of the reciprocable frame and the position of the means to receive the vegetable material to be trimmed by suitable means, such as switches activated by a cam linked to the conveyor drive.

18. A vegetable trimming machine according to any of claims 12 to 17, wherein at least one counter balance is attached by suitable connection means to the reciprocable frame so as to reduce the load on the reciprocating drive.

19. A vegetable trimming machine according to claim 18, wherein the or each at least one counter balance is attached by the suitable connection means to a point on the reciprocable frame which counter balances any imbalance in weight of the reciprocable frame caused by the mounting of components such as the cut¬ ting means thereon.

20. A vegetable trimming machine according to any of claims 12 to 18, wherein a means to smooth the reciprocation of the reciprocable frame is provided.

21. A vegetable trimming machine according to claim 20, wherein the means to smooth the reciprocation of the reciprocable frame comprises a ram, such as an air ram, which acts upon the parallelogram frame.

22. A vegetable trimming machine according to any preceding claim, wherein means are provided for detecting the size of the vegetable material, for ex¬ ample a head of calabrese or cauliflower.

23. A vegetable trimming machine according to claim 22 wherein means are provided for adjusting the movement of the cutting head in accordance with the detected size to vary the cut achieved.

24. A vegetable trimming machine according to claim 22 or 23 , wherein at least two cutting heads of different sizes are provided, each operable according to the detected size of the vegetable material.

25. A vegetable trimming machine according to claim 24, wherein a tim- ing means is provided to vary the delay between the detection of the size of the vegetable material and the actuation of the appropriate cutting head, the delay be¬ ing dependent on the distance between the detection means and the position of the cutting head with respect thereto.

26. A vegetable trimming machine according to any preceding claim, fur¬ ther comprising mounting means to permit each cutting head to slide vertically, and means for sliding the head vertically up and down.

27. A vegetable trimming machine according to claim 26, further com¬ prising a resilient mounting for the means for sliding the head vertically up and down.

28. A vegetable trimming machine according to claim 26 or 27, wherein the mounting means comprise a guide rail and at least one guide roller engageable thereon.

29. A vegetable trimming machine according to at least one of claims 26 to 28, wherein the means for sliding the head vertically up and down comprises a ram means.

30. A vegetable trimming machine according to at least one of claims 26 to 29, wherein the ram means comprises a means for providing an adjustment in¬ crement to vary the operating height of the cutting head selectively.

31. A vegetable trimming machine according to claim 30, wherein the ad¬ justment increment is determined as a function of the vegetable size as detected by the size detecting means.

32. A vegetable trimming machine according to claim 29 or 30, wherein the means for sliding the head vertically up and down comprises two ram means connected in series, the first ram means providing overall movement and the sec¬ ond ram means providing an adjustment increment to vary the operating height of the cutting head selectively.

33. A vegetable trimming machine according to claim 32, wherein the second ram means is in the form of at least one double ended ram operable in dif¬ ferent increments at the opposite ends, in order to achieve a wider range of steps.

34. A vegetable trimming machine according to claim 32, wherein the sec¬ ond ram means is in the form of a single ram the extension of which is controlled by magnetic sensors to produce incremental steps.

35. A vegetable trimming machine according to claim 29 or 30, wherein the means for providing an adjustment increment to vary the operating height of the cutting head selectively comprises slidable shims to limit the travel of the ram means in an incremental manner.

36. A vegetable trimming machine according to at least one of claims 26 to 35, wherein the ram means are pneumatically operable.

37. A vegetable trimming machine according to any preceding claim, comprising a plurality of cutting heads mounted side-by-side, with corresponding size detectors and a set of cups for each.

38. A mobile harvester comprising a vegetable trimming machine accord¬ ing to any preceding claim.