WO2010130691A1

WO2010130691A1 - Panel cutting machine

Info

Publication number: WO2010130691A1
Application number: PCT/EP2010/056375
Authority: WO
Inventors: Renzo Giunti
Original assignee: Erregi Di Giunti Renzo
Priority date: 2009-05-15
Filing date: 2010-05-10
Publication date: 2010-11-18
Also published as: ITMC20090112A1

Abstract

The present industrial invention relates to a machine for cutting panels or sheets of any material, which allows for making both square and curvilinear cuts, according to any type of trajectory; said machine comprises means (5) to grab and move the panel along the longitudinal axis (X) of the machine and a cutting tool, consisting in a milling cutter (8) with vertical axis, supported on a trolley (9) that makes alternate travels according to the transversal axis (Y) of the machine.

Description

Panel cutting machine.

The present patent application for industrial invention relates to a machine for cutting panels or sheets of any material, which allows for making square and curvilinear cuts according to any type of trajectory.

The machine has been devised in order to be primarily used in the furniture industry, therefore from now on reference will be always made to wooden panels, although the same machine can be used with the same efficacy and advantages in other industrial applications, such as to cut marble slabs or sheet metal. Two different types of wooden panel cutting machines are currently available on the market.

The first type of machines comprises a worktable where the individual panels or the stack of panels to be cut lays and slides either forwards or backwards. The panels are moved by means of mechanical clamps that push them forward against a stop situated beyond the cutting line, where a cutting tool operates, consisting in a disk blade mounted on board a trolley situated under said worktable and making alternate rectilinear travels along a direction perpendicular to the forward direction of the panels on said worktable. Such a type of machine is disclosed in patent application DE 103 55 972. This first type of machine only allows for making square cuts, it being evident that, after making the first cut, the panel must be rotated every time by 90° before making the next cut. In spite of this operating limit, said machines are characterized by high production rate.

A second type of machines is characterized in that they are provided, on said worktable, with a cutting tool, consisting of a milling cutter mounted on board a trolley that makes alternate travels according to two orthogonal axes of a Cartesian plane (X-Y). In this type of machines the panel remains still for the entire work cycle, it being evident that any type of trajectory of the cutting line can be obtained by suitably combining the movements of the trolley according to the Cartesian axes (X and Y).

This second type of machines allows for making both square and curvilinear cuts. Against such higher versatility of use, these machines are impaired by the fact that they require the use of the so-called "martyr panel", that is to say a non-reusable panel used to hold the panel to be machined and subjected to surface cutting by the cutting tool during the cutting cycle of the panel to be machined. In fact, the "martyr panel" is a means to hold the panel to be cut, by means of vacuum generated by a suction system that takes advantage of the porosity of the martyr panel. The holding of the panel to cut on the martyr panel is necessary to oppose the stress in longitudinal (X) and transversal direction (Y) generated by the cutter during cutting operations. Therefore, if you want to cut a panel that is held in close contact with another panel by means of vacuum, in order to detach the upper panel, it is necessary to cut the lower panel (hence the name "martyr panel") in each passage of the cutter in longitudinal (X) and transversal (Y) direction. Evidently, after several passages of the cutter, the martyr panel is full of cuts and unable to ensure holding and must be replaced with a new panel.

Patent US 4,895,483 discloses a machine used to make undercut edges in panels. Said machine comprises a milling cutter that can translate along a rectilinear slot. Neither handling means of the panel nor handling means of the cutter are provided. In fact, the panel is moved manually to the cutting position and held in such a position. Only the outline cut of the panel is provided for, and no partial cuts are provided to obtain multiple small panels with different size from the panel. The cutter is moved manually to make the cut that forms the undercut edge of the panel. Evidently, such a machine cannot make curvilinear cuts and the panel must be rotated every time by 90° to make the cut on all its borders.

FR 1 126 846 discloses a panel cutting machine provided with stop bars to hold the panel in position during cutting with a cutter. A second cutter is necessary to make the cut on three borders of the panel.

The purpose of the present invention is to devise a machine for cutting wooden panels that is characterized by the advantages of both types of aforementioned machines without their drawbacks or limits. In other words, the purpose of the present invention is to disclose a machine used to obtain multiple panels of different size from a large panel, which is characterized by high productivity rate and allows for making both square and curvilinear cuts without the use of a "martyr panel".

These and other purposes, which will become evident throughout this description, have been achieved by the machine of the invention, the main characteristics of which are described in the first claim. The machine of the invention comprises a worktable on which the panel to cut is laid or moved, it being grabbed and moved by means of mechanical clamps that push it forwards by a predefined travel beyond the cutting line, in which the cutting tool operates, consisting in a milling cutter mounted on board a trolley, situated on said worktable and adapted to make alternate rectilinear travels along a direction perpendicular to the forward travelling direction of the panels on said worktable.

Therefore, in the machine of the invention, the milling cutter only translates along the cutting line.

To that end the machine is provided with first automatic motorized means to move the clamps that grab the panel in longitudinal direction, and second automatic motorized means to move the milling cutter in transversal direction. This allows making:

- a longitudinal cut of the panel by moving only the clamps along the longitudinal axis,

- a transversal cut of the panel by moving only the milling cutter along the transversal axis, and

- a curvilinear cut of the panel by simultaneously moving the clamps along the longitudinal axis and the milling cutter along the transversal axis.

The separation of the two movements: the movement of the panel that translates along a longitudinal axis, and - the movement of the milling cutter that translates along a transversal axis, eliminates the need to use a martyr panel that must be repeatedly replaced. In fact, the movement of the cutter is only in transversal direction (Y). Therefore, it is possible to use always the same martyr panel that is cut only the first time and maintains its only transversal slot for the entire work cycle. The clamps mechanically hold the panel to be cut against the stress caused by the cutter.

The use of a milling cutter, instead of a disk blade, allows for cutting the panel along two orthogonal directions, without rotating the panel by 90°. Advantageously the worktable is provided with a transversal interruption that originates a slot in which the milling cutter penetrates and translates during the cutting phase. Such a slot is optional and is an improvement to increase the efficacious fall of wood chips by gravity or lower suction. A further purpose of the invention is to devise a machine for cutting wooden panels that collects the panels to be cut from an area situated in the space occupied by the machine, in such a way to ensure the best use of the space available in the shop floor where the machine is installed.

To that end the machine of the invention has been provided with a worktable that translates according to the forward travelling direction of the panels to be cut and an elevator device with suction cups above the worktable and provided with up-down movement, in such a way that the space under the worktable can be used to store the stack of panels to be cut. The operating cycle comprises the following phases:

- forward travel of the worktable - under the cutter - by a distance sufficient to free a passage area for said elevator device with suction cups;

- downward travel of said elevator device and grabbing of first panel on the stack of panels to be cut, which have been previously stored under said translating worktable;

- upward travel of said elevator device with simultaneous elevation of the panel grabbed by it;

- backward movement of the translating worktable until it resumes the initial idle position above the stack of panels to be cut;

- downward travel of said elevator device until the panel to be cut is laid and unloaded on the worktable; - actuation of the clamps designed to move the panel to be cut, which is grabbed and pushed forward by a predefined travel beyond the cutting line;

- start of cutting phase, which involves the transversal movement of the milling cutter only along the cutting line or the longitudinal movement only of the panel to be cut perpendicularly to the cutting line or the simultaneous movement of the milling cutter and panel, respectively along the transversal and longitudinal axis.

For major clarity, the description of the machine of the invention continues with reference to the enclosed drawings, which are only for illustrative, not limitative purposes, wherein:

- fig. 1 is a view of a longitudinal side of the machine of the invention according to the direction indicated by the arrow (F2) of fig. 1 ;

- fig. 2 is a plan view of the machine of fig. 1 ;

- fig. 3 is the same plan view of the machine as fig. 2, except for it does not show said elevator device and relevant support structure in order to provide a better view of the parts of the machine under said device;

- fig. 4 is a view of the rear side of the machine of the invention, according to the direction indicated by the arrow (F3) of fig. 3, meaning by rear side the side from which the cut-to-size panel comes out; in order not to complicate the technical drawing, said elevator device with suction cups and relevant support structure has been omitted, it being illustrated separately in fig. 4;

- fig. 5 is the view of the elevator device with suction cups from the rear side of the machine; in this figure the remaining parts of the machine are not shown; - figs. 6 to 14 show the different positions of the mobile parts of the machine during a work cycle.

Referring to the above figures, the machine of the invention comprises a bearing frame composed of a spaced series of four identical portal structures (T 1 , T2, T3 and T4) transversally arranged and connected, either completely or partially, by longitudinal cross-pieces (L).

The distance between the intermediate portal structures (T2 and T3) is sufficiently large to contain a stack (PL) of panels (P) to be cut. Said frame acts as support for a horizontal worktable (1 ) and for an opposite pair of longitudinal beams (2), on the internal side of which an opposite pair of tracks (B1 ) is fixed to support and guide an opposite pair of identical motorized trolleys (3) connected by a transversal bar (4), on which mechanical clamps (5) of known type are mounted to grab a transversal border (P1 ) of the panel (P).

The simultaneous handling of said identical opposite pair of trolleys (3) is carried out by means of a transversal drive shaft (6) driven into rotation by a motor reducer (7) mounted in the centre of said transversal bar (4). Said shaft (6) is provided at the two ends with two identical toothed wheels (6a) that engage with corresponding racks fixed to the tracks (B1). In order not to complicate fig. 1 , the components designed to actuate the clamps (5) are not shown in fig. 1. The machine of the invention comprises a milling cutter (8), the actuation motor of which (8a) is mounted on a slide adapted to make alternate vertical travels along corresponding vertical tracks of a support trolley (9), consisting in a vertical plate, on which a worm screw (9a) with vertical axis is mounted and driven into rotation by means of a chain-belt drive (9b), a motor (9c) mounted on board said trolley (9), which slides along tracks with horizontal axes (10) fixed to bars (1 1 ) that extend transversally above said longitudinal beams (2).

Also the movement of the trolley (9) along said tracks (10) is obtained with mother-screw and worm-screw coupling, where the worm screw (12) is driven into rotation by a motor (13). Referring to fig. 3, the tablework (1 ) is formed of a fixed half-table (1 a) and a mobile half-table (1 b) separated by a transversal slot (15) that lays on the vertical plane passing through the axis of vertical rotation of the milling cutter (8), with diameter lower than the width of said slot (15), since the milling cutter (8) must penetrate and slide inside said slot (15) during the cutting operation. The trajectory of the cut made on the panel (P), which is grabbed and moved by the clamps (5), depends on the translation speed along the longitudinal axis (X) of the machine given to the clamps (5) and on the translation speed along the transversal axis (Y) of the machine given to the cutter-holding trolley (9).

The cut of the panel (P) along a longitudinal axis (X) is made by holding the milling cutter (8) still and making only the panel (P) translate, whereas the square cut of the panel (P) along a transversal axis (Y) is made by holding the panel (P) still and making only the milling cutter (8) translate.

In order to make curvilinear cuts on the panel (P) it is simply necessary to move both the milling cutter (8) and the panel (P) simultaneously along their axes (X and Y), it being evident that the curvilinear profile of the cut can be made along any trajectory by imposing suitable translation speed values to the cutter-holding trolley (9) on one side and to the panel-holding clamps (5) on the other side.

As mentioned above, the worktable (1 ) is divided into two half-tables, a fixed

(1 a) and a mobile (1 b) half-table. The fixed half-table (1 a) extends astride the first pair of portal structures (T 1 and T2), whereas the mobile half-table (1 b) is situated between the pair of intermediate portal structures (T2 and T3).

The length along direction (X) of the mobile half-table (1 b) is higher than the length of the panels (P) to be cut. The mobile half-table (1 b) can make two movements: the first movement consists in alternate vertical travels, whereas the second movement consists in alternate horizontal travels along direction

(X).

Referring to Figs. 3 and 4, the mobile half-plane (1 b) is hung at the four corners to the stems (20) of four jacks (21 ) with vertical axis, arranged in two opposite pairs.

Each jack (21 ) is mounted on board a bracket (22) that belongs to a trolley

(23) sliding on guide tracks (B2) fixed to the external side of said opposite pair of longitudinal beams (2).

Each pair of trolleys (23) that slides on the same track (B2) is joined by means of a longitudinal connection bar (23a), whereas each opposite pair of tracks (23) that does not slide on the same track (B2) is joined by means of a transversal connection bar (23b). The movement of each pair of trolleys (23) along the corresponding guide track (B2) is determined by a transmission belt (24) actuated by a motor reducer (24a) that drives into rotation a shaft (25) that extends transversally astride the pair of tracks (B2) and supports at the two ends two identical gears (26), each of them cooperating with a toothed transmission belt (24) to which a pair of trolleys (23) is fixed.

In idle condition the mobile half-table (1 b) is coplanar to the fixed half-table (1 a) that according to the preferred embodiment coincides with a conveyor belt (N) that supports the portion of panel (P) situated beyond the cutting line that coincides with said slot (15).

This means that when cutting of a portion of panel has been completed, said portion can be removed from the cutting line by means of the conveyor belt (N) that unloads it from the rear side of the machine (M). When the stems (20) of the jacks (21 ) are extended, the mobile half-table (1 b) is lowered at a lower height than the fixed half-table (1 a). When the shaft (25) is actuated, the two pairs of trolleys (23) move forward along corresponding guide tracks (B2) driving the mobile half-table (1 b) under the fixed half-table (1 a), thus having access from above to the stack of panels (PL) situated in the space between the intermediate pair of portal structures (T2 and T3). The machine of the invention also comprises an elevator device (30) situated between the intermediate pair of portal structures (T2 and T3) and adapted to collect from above the first panel (P) of said stack of panels (PL). Referring to Figs. 1 , 2 and 5, said elevator device (30) comprises an identical pair of vertical arms (31 ), each of them supporting at the base a transversal bar (32) provided with a series of suction cups (33).

Each arm (31 ) can make alternate vertical travels because of sprocket-rack type coupling, wherein the rack is fixed to the arm (31 ) and the sprocket is keyed to a drive shaft (34) with horizontal development according to the longitudinal axis (X) of the machine. A motor reducer (35) actuates said horizontal shaft (34) that supports at the two ends two identical sprockets (36), each of them engaging with a corresponding rack (37). Said elevator (30) is supported by a pair of transversal beams (40) fixed to said longitudinal cross-pieces (L) and situated between the intermediate pair of portal structures (T2 and T3).

When the arms (31 ) are in idle position, the suction cups (33) lay at higher height than the clamps (5). The maximum downward travel of the arms (31 ) has a suitable value to allow said suction cups (33) to take the lowest panel (P) of the stack (PL) of panels (P), as shown in fig. 5. The two arms (31 ) are guided in their alternate up-down travels by corresponding fixed guide structures anchored to said transversal beams (40). Evidently, the machine comprises an electrical installation and a hydraulic installation for actuation of all actuators according to machining data loaded in an electronic control unit to program, manage and control the entire operating cycle that comprises the following sequence of operating phases, as shown in figs. 6 to 14: - downward travel (see fig. 7) of the mobile half-table (1 b) starting from idle position (see fig. 6), wherein it is aligned and coplanar with the fixed half-table

(1 a);

- forward movement of the mobile half-table (1 b) under the fixed half-table (1 a), as shown in fig. 8; - downward travel of said arms (31 ) and grabbing by suction cups (33) of the highest panel of the stack (PL) of panels (P) to be machined, as shown in fig. 9;

- rising of said arms (31 ) with simultaneous rising of the grabbed panel (P) as shown in fig. 10; - complete backward travel of the mobile half-table (1 b) as shown in fig. 1 1 ;

- rising of the mobile half-table (1 b) until it resumes its initial idle position in coplanar position to the fixed table (1 a), as shown in fig. 12;

- downward travel of the arms (31 ) until the panel (P) to be cut is laid and unloaded on the mobile half-table (1 b), as shown in fig. 13; - rising of the arms (31) and actuation of the clamps (5) used to move the panel to be cut, which is grabbed and pushed forward by a predefined travel beyond the slot (15), as shown in fig. 14; - start of the cutting phase, which involves the transversal movement only of the milling cutter (8) along the cutting line or the longitudinal movement only of the panel (P) to be cut perpendicularly to the cutting line or the simultaneous movement of the milling cutter (8) and the panel (P), respectively along the transversal (Y) and longitudinal (X) axis of the machine.

Claims

1 ) Panel cutting machine comprising:

- a worktable (1 ) that supports a panel (P) to be cut,

- a cutting tool (8) mounted on a vertical slide, said slide being provided with guide tracks mounted on a trolley (9) that makes horizontal alternate travels according to a transversal axis (Y) of the machine, in such a way to define a cutting line,

- mechanical clamps (5) to grab said panel (P),

- first automatic motorization means (6, 7) to move said clamps (5) in translation along a longitudinal axis (X) of the machine, in such a way to drive the panel into alternate travels along said longitudinal axis (X), until it is pushed beyond said cutting line, characterized in that said cutting tool consists in a milling cutter (8) with vertical axis and it being provided second automatic motorization means (9b, 9c) to move said milling cutter (8) in translation along the vertical axis (Y) of the machine, in such a way to obtain:

- a longitudinal cut of the panel (P) by moving only the clamps (5) along the longitudinal axis (X),

- a transversal cut of the panel (P) by moving only the milling cutter (8) along the transversal axis (Y), and

- a curvilinear cut of the panel (P) by simultaneously moving the clamps (5) along the longitudinal axis (X) and the milling cutter (8) along the transversal axis (Y).

2) Machine as claimed in the above claim, characterized in that it comprises a frame (T1 , T2, T3, T4) that supports said worktable (1 ) and an opposite pair of longitudinal beams (2), on the internal side of which an opposite pair of tracks (B1 ) is fixed to support and guide an opposite pair of identical motorized trolleys (3) connected by a transversal bar (4), on which said mechanical clamps (5) are mounted. 3) Machine as claimed in the above claim, characterized in that said first automatic motorization means (6, 7) comprise a motor reducer (7) mounted in the centre of said transversal bar (4) that drives into rotation a transversal drive shaft (6) that moves said identical opposite pairs of trolleys (3), said shaft (6) being provided at the two ends with two identical toothed wheels (6a) that engage with corresponding racks fixed to the tracks (B1 ).

4) Machine as claimed in any one of the above claims, characterized in that the worktable (1 ) is divided into two half-tables, a fixed (1 a) and a mobile (1 b) half-table, the fixed half-table (1 a) being mounted downstream said transversal slot (15), whereas the mobile half-table (1 b) can make two movements: the first movement consists in alternate vertical travels, whereas the second movement consists in alternate horizontal travels according to a direction parallel to the longitudinal axis (X).

5) Machine as claimed in the above claim, characterized in that said mobile half-table (1 b) is hung at the four corners to the stems (20) of four jacks (21 ) with vertical axis, arranged in opposite pairs, each of them being mounted on board a bracket (22) that belongs to a trolley (23) that slides on guide tracks (B2) fixed on the external side of said opposite pair of longitudinal beams (2).

6) Machine as claimed in the above claim, characterized in that each pair of trolleys (23) is moved along the corresponding guide track (B2) by a transmission belt (24) actuated by a motor reducer (24a) that drives into rotation a shaft (25) that extends transversally astride the pair of tracks (B2) and supports at the two ends two identical gears (26), each of them cooperating with a toothed transmission belt (24) to which a pair of trolleys (23) is fixed.

7) Machine as claimed in claim 4, characterized in that said fixed half-table (1 a) is a conveyor belt (N). 8) Machine as claimed in one or more of claims 4 to 7, characterized in that it comprises an elevator device (30) to take the highest panel (P) from a stack (PL) of panels situated under the mobile half-table (1 b) between the intermediate pair of portal structures (T2 and T3).

9) Machine as claimed in the above claim, characterized in that said elevator device (30) comprises a pair of identical vertical arms (31 ), each of them supporting at the base a transversal bar (32) provided with a series of suction cups (33) and characterized in that each arm (31 ) can make alternate vertical travels because of a sprocket-rack type coupling, wherein the rack (37) is fixed to the arm (31) and the sprocket (36) is keyed on a drive shaft (34) with horizontal development along the longitudinal axis (X) of the machine and supports at the two ends two identical sprockets (36), each of them engaging with a corresponding rack (37).

10) Machine as claimed in any one of the above claims, characterized in that said second automatic motorization means (9b, 9c) comprise a motor (9c) mounted on board said trolley (9) that drives into rotation a worm screw (9a) with vertical axis by means of a chain-belt drive (9b).

1 1 ) Machine as claimed in any one of the above claims, characterized in that said worktable (1 ) is provided with a transversal slot (15) that lays on the vertical plane passing through the axis of vertical rotation of the milling cutter (8), with diameter lower than the width of said slot (15).