WO2008120052A1

WO2008120052A1 - Cutting apparatus

Info

Publication number: WO2008120052A1
Application number: PCT/IB2008/000541
Authority: WO
Inventors: Roberto Marcante; Monica Bianchin
Original assignee: Costruzioni Meccaniche Isola-S.R.L.
Priority date: 2007-04-03
Filing date: 2008-03-07
Publication date: 2008-10-09
Also published as: EP2152483A1; ITMO20070119A1

Abstract

A cutting apparatus comprises cutting means (2) for cutting portions (3) from an extruded product (4) made of clay material, advancing means (5) for advancing said extruded product (4) along an advancing direction (A), and further comprises driving means (20, 30, 41) arranged for driving said advancing means (5) along said advancing direction (A) and further driving means (62, 64) arranged for driving said cutting means (2) along a direction that is transverse to said advancing direction (A), said driving means (20, 30, 41) being distinct from said further driving means (62, 64).

Description

Cutting apparatus

The invention relates to a cutting apparatus for cutting an extruded product, in particular made of clay material, for manufacturing fired products . Cutting apparatuses are known for cutting fired products, comprising advancing means arranged for moving along an advancing direction an extruded product, consisting of a continuous element made of clay material coming from an extruder, and cutting means, provided with a cutting wire such as to interact with the extruded product to divide the extruded product into portions .

The cutting means is movable with alternating movement between a raised position in which the cutting wire is above the extruded product and a lowered position in which, the cutting wire is below the extruded product . By moving from the raised position to the lowered position the cutting wire traverses the extruded product, separating a portion therefrom that is arranged downstream of the still continuous extruded product. The advancing means comprises a carriage that is movable with alternating movement that guides the front of the extruded product during the cutting operation along the advancing direction and returns along a direction opposite the advancing direction, sliding below the cut extruded product, to a front of extruded product generated by the action of the cutting means . The advancing means further comprises, upstream of the carriage, an inlet conveyor on which the extruded product entering the cutting apparatus rests, downstream of the carriage, an outlet conveyor that supports the cut portions of extruded product exiting the cutting apparatus.

As the extruded product, advanced by the carriage, moves during cutting along the advancing direction, to obtain a cutting profile that is substantially orthogonal to the advancing direction, the cutting means has to move not only in a direction that is perpendicular to the advancing direction but also along the advancing direction, at the same speed as the carriage. This is obtained by connecting the carriage and the cutting means by mechanical members, for example a cam or mechanical transmission, the latter being driving by a common engine . A drawback of the cutting apparatuses disclosed above is that the mechanical members that connect the carriage and the cutting means need to be adjusted on the basis of the dimensions of the extruded product to be cut. This means that the cutting apparatus has to be stopped, in order that adjusting can occur, with considerable loss of time and increased production costs.

Further, such mechanical members become worn with use and cause rather imprecise operation of the cutting apparatus . In order to compensate for wear to such mechanical members it is thus necessary to add further downtime. This further downtime entails production loss.

Adjusting operations are thus rather complicated and require expert operators who have been appropriately informed about the features of the cutting apparatus . In known cutting apparatuses, the extruded product may be ruined during motion of the cutting means, this entailing the production of defective portions of extruded material that have to be discarded. Another drawback of known cutting apparatuses is that the carriage is distanced alternatively from the inlet conveyor. When the carriage is further from the inlet conveyor, a part of the extruded product, not being supported by either the carriage or the inlet conveyor, may flex by gravity and thus be spoilt. Further, when the carriage delivers the cut portions to the outlet conveyor, the cut portions may knock against the outlet conveyor, and consequently become dented. An object of the invention is to improve cutting apparatuses of known type. A further object is to produce a cutting apparatus that enables a wide range of extruded products to be processed without adjusting of mechanical members being necessary. Still a further object is to obtain an efficient and precise cutting apparatus, in which the production of defective portions of extruded product is limited or even eliminated. Another object is to obtain a cutting apparatus in which the interventions of expert operators are limited. Still another object is to obtain a cutting apparatus that substantially enables each part of the extruded product to be supported, preventing the extruded product from being able to flex or knock against elements of the cutting apparatus . In a first aspect of the invention there is provided a cutting apparatus comprising cutting means for cutting portions from an extruded product made of clay material and advancing means for advancing said extruded product along an advancing direction, characterised in that it further comprises driving means arranged for driving said advancing means along said advancing direction and further driving means arranged for driving said cutting means along a direction that is transverse to said advancing direction, said driving means being distinct from said further driving means . Owing to the invention it is not necessary to connect the cutting means and the advancing means by mechanical members driven by a common motor, as occurs in prior-art cutting apparatuses . This enables the downtime to be avoided that in known apparatuses was necessary to adjust the mechanical members on the basis of the dimensions of the extruded product or due to wear.

As the driving means is distinct from the further driving means it is possible to drive the cutting means independently of the advancing means . This gives the cutting apparatus very precise operation, reducing, or even eliminating, the number of defective portions obtained during cutting.

In an embodiment, the driving means and the further driving means are operated by a control unit, for example a controller of the motion control type.

Owing to this embodiment, it is possible to modify the cutting profile in a substantially automated manner, avoiding expert operators intervening to adjust the mechanical members of the cutting apparatus .

Further, it is possible to process a wide range of extruded products in rather a simple and efficient manner, limiting downtime, and thus the costs linked to the production change . In a second aspect of the invention there is provided a cutting apparatus for cutting portions from an extruded product made of clay material comprising carriage means movable between a retracted position, in which said carriage means is nearer an inlet zone of said cutting apparatus, and an advanced position, in which said carriage means is nearer an outlet zone of said cutting apparatus, and conveying means arranged for conveying said extruded product along an advancing direction, characterised in that said conveying means comprises an end mounted on said carriage means . Owing to this aspect of the invention, the carriage means and the conveying means continuously support the extruded product without parts of the extruded product being able to flex and be inserted between gaps provided between the carriage means and the conveying means . The invention can be better understood and implemented with reference to the attached drawings that illustrate an embodiment thereof by way of non-limiting example, in which: Figure 1 is a side view of a cutting apparatus for cutting an extruded product made of clay material; Figure 2 is a plan view of the cutting apparatus in Figure 1; Figure 3 is a section taken along the plane III-III inFigure l_;

Figure 4 is a section taken along the plane IV-IV in Figure

1; Figures 5 to 9 are schematic side views of a part of the cutting apparatus in Figure 1 during subsequent operating instants .

Figures 1 and 2 show a cutting apparatus 1 comprising a base structure 6 on which advancing means 5 is mounted, arranged for advancing an extruded product 4 (Figures 5-9) made of clay material along an advancing direction A from an inlet zone 7 to an outlet zone 8.

The cutting apparatus 1 further comprises, in a cutting zone 18 , cutting means 2 intended for separating portions 3 (Figures 5-9) from the extruded product 4, for example for the production of fired products, such as bricks, roof tiles, bent tiles, blocks or hollow tiles for floors. The advancing means 5 comprises a conveyor, in particular an extendible or telescopic conveyor 11. The extendible conveyor 11 is provided with a belt 12 wound sequentially around a driving roller 13, a first driven roller 14, a first end roller 15, a second end roller 16 and a second driven roller 17. The driving roller 13, the first driven roller 14 and the first end roller 15 are supported on the base structure 6. The second end roller 16 and the second driven roller 17 are movable alternately along a direction parallel to the advancing direction A so that the distance between the first end roller 15 and the second end roller 16 can vary between a minimum value, corresponding to a retracted configuration of the extendible belt 11 - shown in Figure 1 - and a maximum value corresponding to an extended configuration of the extendible belt 11. The belt 12 rotates around the rollers 13, 14, 15, 16 and 17 dragged by the driving roller 13. The driving roller 13 is driven by a motor 20, mounted on the base structure 6. The rotation of the driving roller 13 is such that the portion of belt 12 comprised between the first end roller 25 and the second end roller 26 is substantially flat and moves according to the advancing direction A.

The advancing means 5 further comprises a carriage 19, arranged in the cutting zone 18 and movable with alternating movement between a retracted position B, shown in Figures 1, 5 and 9, in which the carriage 19 is nearer the inlet zone 7, and an advanced position C, shown in Figure 8, in which the carriage 19 is nearer the outlet zone 8. As will be disclosed better below, a movable part of the extendible conveyor 11 is mounted on the carriage 19. As shown in Figure 3, the carriage 19 comprises a base 31 below which pads 32 are fixed that are slidable on guides 33 mounted on opposite sides of the base structure 6. The base 31 supports a plurality of resting elements 34, arranged transversely to the advancing direction A. The resting elements 34 are placed alongside one another and are intended for supportingly receiving the extruded product 4 and the portions 3 that are cut therefrorα. Each resting element 34 comprises a plate 35 mounted on a rod 36 at the ends of which supporting feet 37 are provided so as to distance the rod 36 from the base 31. As shown in Figures 5 to 9, between a resting element 34 and the adjacent resting element a space 38 is interposed. Each plate 35 projects from the respective rod 36 parallel to the advancing direction A. Between each plate 35 and an adjacent plate 35 there is a gap 37-

As shown in Figure 2, the carriage 19 is driven by driving means 41. The driving means 41 comprises motor means 42 that rotates a screw 43, for example a worm screw, along which a nut screw 44 travels. The nut screw 44 is fixed to a connecting member 45 (Figure 3) mounted below the base 31. When the motor means 42 drives the screw 43 in a first rotation direction, the nut screw 44 moves from a first end 46 to a second end 47 of the screw 43. When the motor means 42 drives the screw 43 in a second rotation direction, opposite the first rotation direction, the nut screw 44 moves from the second end 47 to the first end 46 of the screw 43. The stroke of the nut screw 44 on the screw 43 thus corresponds to the stroke of the carriage 19. Thus, when the nut screw 44 is at the first end 46, the carriage 19 is in the retracted position B and when the nut screw 44 is at the second end 47, the carriage 19 is in the advanced position C. The advancing means 5 further comprises a further conveyor, in particular a further extendible or telescopic conveyor 21.

A movable part of the further extendible conveyor 21 is mounted on the carriage 19. The further extendible conveyor 21 is functionally configured as the extendible conveyor 11 and is therefore provided with a further belt 22 wound in sequence on a further driving roller 23, a further first driven roller 24, a further first end roller 25, a further second end roller 26 and a further second driven roller 27. The further driving roller 23, the further first driven roller 24 and the further first end roller 25 are supported on the base structure 6. The further second end roller 26 and the further second driven roller 27 are movable with alternating motion along a direction parallel to the advancing direction A so that the distance between the further first end roller

25 and the further second end roller 26 can vary between a further maximum value, corresponding to an extended configuration of the further extendible belt 21 - shown in Figure 1 - and a further minimum value, corresponding to a retracted configuration of the further extendible belt 21. The further belt 22 rotates around the rollers 23, 24, 25,

26 and 27 dragged by the further driving roller 23. The further driving roller 23 is driven by a further motor 30, mounted on the base structure 6. Rotation of the further driving roller 23 is such that the portion of belt 22 comprised between the further second end roller 26 and the further first end roller 25 is substantially flat and moves according to the advancing direction A.

The extendible conveyor 11 and the further extendible conveyor 20 are connected to the carriage 19, so as to extend or respectively retract when the carriage 19 moves between the retracted position B and the advanced position C. Figures 5-9 show that the second end roller 16 is connected to an end 28 of the carriage 19 and the further second end roller 26 is connected to a further end 29 of the carriage 19, this further end being opposite the end 28. As shown in Figure 4, through supports 40 the further second end roller 26 transmits alternating movement to the further second driven roller 27. Similarly, through supports, which are not shown, the second end roller 16 transmits alternating motion to the second driven roller 17.

When the carriage 19 is in the retracted position B the extendible conveyor 11 is in the retracted configuration whilst the further extendible conveyor 21 is in the extended configuration (Figure 1} . When the carriage 19 moves from the retracted position B to the advanced position C, the extendible conveyor 11 moves from the retracted configuration to the extended configuration, whilst the further extendible conveyor 21 moves from the extended configuration to the retracted configuration. On the other hand, when the carriage 19 moves from the advanced position C to the retracted position B, the extendible conveyor 11 moves from the extended configuration to the retracted configuration, whilst the further extendible conveyor 21 moves from the retracted configuration to the extended configuration. The difference between the maximum value and the minimum value of the distance between the first end roller 15 and the second end roller 16 is thus the same as the stroke of the carriage 19. Similarly, the difference between the further maximum value and the further minimum value of the distance between the further first end roller 25 and the further second end roller 26 is thus the same as the stroke of the carriage 19. The motor 20, the further motor 30 and the motor means 42 can, for example, be brushless motors. Owing to the extendible conveyor 11 and the further extendible conveyor 21 it is possible to maintain the extruded product 4 supported on a substantially continuous surface . This enables to prevent that the extruded product 4 may become spoilt when it is transferred from the extendible conveyor 11 to the carriage 19 and, once the extruded product, has been cut, when it is transferred from the carriage 19 to the further extendible conveyor 21. In fact, compared with prior-art cutting apparatuses, empty gaps are not formed in the cutting apparatus 1 between the extendible conveyor 11 and the carriage 19 and between the latter and the further extendible conveyor 21 during motion of the carriage 19. Each part of the extruded product 4 is thus properly supported. Further, the portions 3 are transferred to the further extendible conveyor 21 without the portions 3 encountering obstacles against which they can knock and be spoilt .

With reference to Figures 1 and 3, the cutting means 2 comprises a plurality of cutting wires 48, for example two cutting wires (Figures 5-9), or three cutting wires, each cutting wire 48 having an end portion 49 fixed to a fixing plate 51 and a further end portion 50 fixed to a tensioning device 52. The cutting wire 48 is tensioned between the fixing plate 51 and a further fixing plate 55. The cutting wire 48 may have a tilted configuration, similar to the profile of a guillotine blade, or a substantially horizontal configuration .

The fixing plate 51 and the further fixing plate 55 are mounted on opposite sides of a portal structure 56 arranged in the cutting zone 18 above the carriage 19. The portal structure 56 comprises four uprights 57 fixed near four vertices of the base 31 of the carriage 19. The uprights 57 are connected by crosspieces 58. The fixing plate 51 and the further fixing plate 55 are arranged parallel to the advancing direction A and have ends fixed to guiding elements 59 that are slidable along guiding rods 60. The guiding rods 60 are fixed to the uprights 57.

The fixing plate 51 is driven to slide along the respective guiding rods 60 by a first bar 61, an end of which is hinged on a central zone of the fixing plate 51 and a further end is connected to a first actuator 62. The further fixing plate 56 is driven to slide along the respective guiding rods 60 by a second bar 63, an end of which is hinged on a central zone of the further fixing plate 55 and a further end is connected to a second actuator 64. The first actuator 62 and the second actuator 64 comprise, for example, brushless motors connected to respective transmitting elements. The first actuator 62 and the second actuator 64 are operated to drive the respective fixing plates 51, 55 synchronously . The cutting means 2 is thus movable with alternating movement in a direction that is substantially orthogonal to the advancing direction A, between a first position D, shown in Figures 1, 3, 5, 8 and 9, in which the cutting wire 48 is above the extruded product 4 and a second position E, shown in Figures 6 and 7, in which the cutting wire 48 is below the extruded product 4. By moving from the first position D to the second position E, the cutting wire 48 traverses the extruded product 4 separating a portion 3 therefrom arranged downstream of the still continuous extruded product 4. If the cutting wires 48 are for example 2, the cutting means 2, separates two portions 3 from the continuous extruded product 4.

In the second position E, the cutting wires 48 are housed in the spaces 38, below the plates 35 of the carriage 19. In order to reach the second position E, the cutting wires 48 move into the gaps 39 provided between two adjacent plates 35. As the portal structure 56 is mounted on the carriage 19, during cutting, i.e. during the descent of the cutting wires 48 from the first position D to the second position E, the cutting means 2 is driven to move also along the advancing direction A at the same speed as the carriage 19. This enables a cutting profile to be obtained that is substantially orthogonal to the advancing direction A. With reference to Figures 5 to 9 , in the retracted position B of the carriage 19, shown in Figure 5, the extruded product 4 comprises a front 65 that is supported by the further extendible conveyor 21. The extruded product 4 is thus supported in the cutting zone 18 by the extendible conveyor 11, by the carriage 19 and by the further extendible conveyor 21. From the retracted position B the carriage 19 moves parallel to the advancing direction A to the advanced position C at a movement speed Fl that is the same as the rotation speed Rl of the extendible conveyor 11 (Figure 6) . In the meantime, the cutting means 2, of which in Figures 5-9 the positions of the cutting wires 48, in particular of two cutting wires 48, are shown by asterisks, moves from the first position D to second position E, below the plates 35 of the carriage 19 through the gaps 39. From the extruded product 4 two portions 3 are thus cut and a new front 65' of the extruded product 4 is determined. A first portion 3a is situated at least partially on the further conveyor 21 and a second portion 3b is situated entirely on the carriage 19. Subsequently, the carriage 19 still proceeds to the advanced position C at a movement speed F2 that is greater than the rotation speed Rl of the extendible conveyor 11. The movement speed F2 is nevertheless less than the rotation speed Tl of the further conveyor 21. The first portion 3a is thus moved away from the second portion 3b because it is dragged by the further conveyor 21, which is faster than the carriage 19. Further, the second portion 3b is moved away from the new front 65' as it is conveyed by the carriage 19, which is here faster than the extendible conveyor 11. In other words, between the first portion 3a and the second portion 3b and between the second portion 3b and the new front 65' slits are formed through which the cutting wires 48 can rise, moving from the second position E to the first position D (Figure 8) . The carriage 19 has in the meantime reached the advanced position C. From the advanced position C the carriage 19 returns to the retracted position B at a movement speed F3 in a direction opposite the advancing direction A, sliding below the extruded product 4, to the new front 56' until the new front 56' is in a preset position on the further extendible conveyor 21. The portions 3a and 3b are thus transferred to the further extendible conveyor 21, which conveys the portions 3a and 3b to the outlet zone 8. The cutting means 2 is above a part of the extruded product 4 that is still to be cut. The cutting cycle can thus be repeated, as disclosed above. With respect to prior-art cutting apparatuses, the cutting means 2 and the advancing means 5 are moved by distinct drives, in particular the cutting means is driven by the first actuator 62 and by the second actuator 64, whilst the carriage 19 is driven by the motor means 42, the extendible conveyor 11 is rotated by the motor 20 and the further extendible conveyor 21 is rotated by the further motor 30. The cutting apparatus 1 does not therefore require the mechanical adjustments provided in known apparatuses.

The motor 20, the further motor 30, the motor means 42 and the actuators 62 and 64 are operated by a control unit, which is not shown, for example a controller of the motion control type. The movement of the cutting means 2 and of the advancing means 5 is adjusted by the control unit. In particular, the control unit adjusts the operation of the single movable parts of the cutting apparatus 1 on the basis of the type of extruded product 4 to be processed. For each type of extruded product 4, it is thus possible to select the corresponding operating mode for the cutting means 2 and for the advancing means 5. The selection can occur through a display connected to the control unit.

This gives the cutting apparatus 1 significant precision and efficiency. Further, with the cutting apparatus 1 it is possible to process a wide range of extruded products in rather a simple manner and without loss of time.

In fact, it is sufficient to select, through the display, the operating mode corresponding to the extruded product that it is desired to process. The control unit adjusts the operation - i.e. speed and accelerations - of the advancing means 5 and of the cutting means 2 so that operation takes account of the features of the selected extruded product.

^' Owing to the cutting apparatus 1, it is thus possible to obtain a substantially orthogonal cut and portions 3 having dimensions that are constant over time.

The cutting apparatus 1 further comprises an inlet belt 9, arranged in the inlet zone 7 and intended for receiving the extruded product 4 coming from an extruder, which is not shown.

The cutting apparatus 1 further comprises, downstream of the inlet belt 9 and upstream of the extendible conveyor 11, a control belt 10 provided with detecting means, which is not shown, for detecting the presence and the speed of the extruded product 4.

The detecting means is connected to the control unit. In this way, the detecting means measures the speed of the extruded product 4 in the inlet zone 7 and sends a signal to the control unit. The latter adjusts the operation of the cutting apparatus 1 on the basis of the detected speed, and modifies, if necessary, the parameters of the cutting process, i.e. the rotation speed Rl of the extendible conveyor 11, the movement speeds Pl, F2 and F3 of the carriage 19, the rotation speed Tl of the further conveyor 21 and the descent and reascent speed of the cutting means 2. Owing to the cutting apparatus 1, it is possible to prevent the cut portions being spoilt during the reascent . of the cutting wires 48. In fact, the control of the rotation speed Rl of the extendable conveyor 11, of the movement speeds Fl, F2 and F3 of the carriage 19 and of the rotation speed Tl of the further conveyor 21 enables slits to be formed between the cut portions through which the cutting wires 48 can pass without interacting with the cut portions or with the extruded product. .

Claims

1. Cutting apparatus comprising cutting means (2) for cutting portions (3) from an extruded product (4) made of clay material and advancing means (5) for advancing said extruded product (4) along an advancing direction

(A) , characterised in that it further comprises driving means (20, 30, 41) arranged for driving said advancing means (5) along said advancing direction (A) and further driving means (62, 64) arranged for driving said cutting means (2) along a direction that is transverse to said advancing direction (A) , said driving means (20, 30, 41) being distinct from said further driving means (62, 64) .

2. Cutting apparatus according to claim 1, wherein said advancing means (5) comprises carriage means (19) movable between a retracted position (B) , wherein said carriage means (19) is nearer an inlet zone (7) of said cutting apparatus (1) , and an advanced position (C) , wherein said carriage means (19) is nearer an outlet zone (8) of said cutting apparatus (1) .

3. Cutting apparatus according to claim 2, wherein said driving means (20, 30, 41) comprises motor means (41) associated with said carriage means (19) .

4. Cutting apparatus according to any preceding claim, wherein said advancing means (5) further comprises conveying means (9, 10, 11, 21) .

5. Cutting apparatus according to claim 4, wherein said conveying means (9, 10, 11, 21) comprises extendible conveying means (11, 21) , said extendible conveying means (11, 21) being extendible from a minimum length to a maximum length.

6. Cutting apparatus according to claim 5 as claim 4 is appended to claim 2 or 3 , wherein said extendible conveying means (11, 21) comprises an end (16, 26) fixed to said carriage means (19) .

7. Cutting apparatus according to claim 6, wherein the difference between said maximum length and said minimum length is the same as a stroke of said carriage means (19) .

8. Cutting apparatus according to claim 6, or 7, wherein said extendible conveying means (11, 21) comprises a first extendible conveyor (11) and a second extendible conveyor (21) , said carriage means (19) being interposed between said first extendible conveyor (11) and said second extendible conveyor (21) .

9. Cutting apparatus according to any one of claims 4 to 8, wherein said driving means (20, 30, 41) comprises further motor means (20, 30) associated with said conveying means (9, 10, 11, 21) . 10. Cutting apparatus according to claim 9, wherein said conveying means (9,

10, 11, 21) comprises support surface means (12, 22) intended for supporting said extruded product (4) and drivable along a closed path by said further motor means (20, 30) .

11. Cutting apparatus according to claim 9 or 10 as claim 9 is appended to claim 8, wherein said further motor means (20, 30) comprises a first motor (20) associated with said first extendible conveyor (11) and a second motor (30) associated with said second extendible conveyor (21) .

12. Cutting apparatus according to any one of claims 2 to 11, wherein said advancing means (5) further comprises belt conveying means (9, 10) arranged in said inlet zone (7) of said cutting apparatus (1) .

13. Cutting apparatus according to claim 12, wherein said belt conveying means (9, 10) comprises a first belt conveyor (9) intended for receiving said extruded product (4) coming from extruding means and a second belt conveyor (10) downstream of said first belt conveyor (9) .

14. Cutting apparatus according to claim 13, wherein said second belt conveyor (10) comprises detecting means for detecting the speed of said extruded product (4) .

15. Cutting apparatus according to any preceding claim, wherein said cutting means (2) is movable between a first position (D) wherein said cutting means (2) is at a higher level than said advancing means (5) , and a second position (E) wherein said cutting means (2) is at a lower level than said advancing means (5) .

16. Cutting apparatus according to claim 15, wherein said further driving means comprises actuating means (62, 64) associated with said cutting means (2) .

17. Cutting apparatus according to claim 15, or 16, wherein said cutting means (2) is further movable along a direction substantially parallel to said advancing direction (A) .

18. Cutting apparatus according to claim 17 as claim 15 is appended to claim 2, or 3 , or to any one of claims 4 to 14 as claim 4 is appended to claim 2 or 3 , wherein said cutting means (2) is supported by supporting means (56) mounted on said carriage means (19) .

19. Cutting apparatus according to any preceding claim wherein said cutting means (2) comprises a cutting wire

(48) .

20. Cutting apparatus according to any preceding claim, and further comprising a control unit connected to said driving means (20, 30, 41) and to said further driving means (62, 64) for controlling and modifying the operation of said driving means (20, 30, 41) and of said further driving means (62, 64) .

21. Cutting apparatus (1) for cutting portions (3) from an extruded product (4) made of clay material comprising carriage means (19) movable between a retracted position (B) , in which said carriage means (19) is nearer an inlet zone (7) of said cutting apparatus (1) , and an advanced position (C) , in which said carriage means (19) is nearer an outlet zone (8) of said cutting apparatus (1) , and conveying means (11, 21) arranged for conveying said extruded product (4) along an advancing direction (A) , characterised in that said conveying means (11, 21) comprises an end (16, 26) mounted on said carriage means (19) .

22. Cutting apparatus according to claim 21, wherein said end is movable.

23. Cutting apparatus according to claim 22, wherein said conveying means comprises extendible conveying means

(11, 21) , said extendible conveying means being extendible from a minimum length to a maximum length.

24. Cutting apparatus according to claim 23, wherein the difference between said maximum length and said minimum length is substantially equal to a stroke of said carriage means (11) .

25. Cutting apparatus according to claim 23, or 24, wherein said extendible conveying means (11, 21) comprises a first extendible conveyor (11) and a second extendible conveyor (21) , said carriage means (19) being interposed between said first extendible conveyor (11) and said second extendible conveyor (21) .