TILTING POLISHING MACHINE FOR MACHINING AN EDGE OF A PLATE.

The present patent application for industrial invention relates to a tilting polishing machine suitable for polishing the edges of plates of hard material, such as for example marble, granite, stone, glass, synthetic materials, and the like.

Two types of polishing machines are known for machining a perimeter edge of a plate. A first type of polishing machine provides for machining the edges of the plate by positioning said plate vertically. A second type of polishing machine provides for machining the edges of the plate by positioning said plate horizontally.

The polishing machines of the first type comprise a conveyor belt disposed in such a way as to have a vertical support surface. The conveyor belt is suitable for supporting and transporting the plate in vertical position from a loading area to an unloading area.

The polishing machines of the first type comprise a plurality of tool assemblies suitable for machining the edges of the plate. Each tool assembly comprises a mandrel provided with a polishing head, and an electrical motor directly connected to the mandrel in order to drive the mandrel into rotation. Advantageously, the mandrel is disposed under the plate, in such a way as to machine a lower edge of the plate.

In order to hold the plate in suspended vertical position above the mandrel against the support surface of the conveyor belt, the machines of the prior art comprise rollers provided with a head made of soft material, such as rubber or polyurethane, which are suitable for pushing the plate against the conveyor belt, opposing the thrust of the tool assemblies.

Such polishing machines of the first type are not versatile and can only be used with small-sized plates. In fact, such machines cannot be used to machine the edges of large-sized plates. As a matter of fact, because of its weight and volume, a large-sized plate could not be transported or machined in vertical position by a machine of the first type.

Large-sized plates are machined with the machines of the second type, which comprise a conveyor belt with a horizontal support surface and mandrels disposed on one side of the conveyor belt, in order to machine an edge of the plate supported by the conveyor belt.

In the machines of the second type, the rollers are disposed above the conveyor belt in order to push the plate against the conveyor belt and towards the mandrels.

However, the machines of the second type are impaired by a very large volume and high energy consumption. Therefore, said machines are only used for very large plates.

So, in order to machine both small-sized plates and large-sized plates, both a machine of the first type and a machine of the second type must be provided. Consequently, a large working area must be provided to install both the machine of the first type and the machine of the second type.

The purpose of the present invention is to overcome the drawbacks of the prior art by providing a versatile machine that is suitable for machining the edge of a plate with large or small size.

An additional purpose is to provide a machine that is comfortable, practical, easy to use and with reduced volume.

These purposes are achieved according to the invention with the characteristics of the appended independent claim 1 .

Advantageous embodiments appear from the dependent claims.

The machine for machining an edge of a plate according to the present invention comprises a fixed frame with a base and a conveyor belt that revolves around two idler rolls in such a way as to define a support surface intended to support and transport the plate.

The machine of the invention comprises a plurality of pressers suitable for pushing the plate against the support surface of the conveyor belt and at least one tool assembly comprising a mandrel provided with a rotating head disposed near one side of the conveyor belt in order to machine the edge of the plate, and an actuator to drive the mandrel into rotation.

The peculiarity of the machine according to the invention consists in the fact that the machine comprises a mobile frame hinged to the fixed frame. The conveyor belt, the pressers and said at least one tool assembly are mounted on the mobile frame. The mobile frame is hinged to the fixed frame in such a way that the mobile frame can rotate around a horizontal hinging axis to go from a first position, wherein the support surface of the conveyor belt is horizontal, to a second position, wherein the support surface of the conveyor belt is vertical.

For the sake of clarity, the description of the machine of the invention continues with reference to the attached drawings, which have a merely illustrative, not limiting value, wherein:

Fig. 1 is an axonometric view of a machine according to the invention, wherein the support surface of the conveyor belt is in horizontal position;

Fig. 2 is a sectional view taken along the sectional plane ll-ll of Fig.

1 ;

Fig. 3 is a sectional view taken along the sectional plane Ill-Ill of Fig.

1 , which shows a plate disposed on the support surface of the conveyor belt;

Fig. 4 is the same as Fig. 3, except for it shows the support surface of the conveyor belt in vertical position.

With reference to Figs. 1 to 4, a machine according to the invention is disclosed, which is generally indicated with reference numeral (100).

The machine (100) is suitable for polishing a lateral edge of a plate (L). The machine (100) comprises a fixed frame (1 ) and a mobile frame (5) hinged to the fixed frame (1 ) by means of hinging means (M), in such a way as to rotate around a horizontal hinging axis (Y).

Said hinging means (M) may provide for any type of rotary system between the fixed frame (1 ) and the mobile frame (5). For example, the hinging means (M) may consist in a rotating bearing comprising an external ring and an internal ring that are revolvingly mounted. For example, the external ring may be connected to the fixed frame (1 ) and the internal ring may be connected to the mobile frame (5).

Alternatively, the hinging means (M) may comprise thrust blocks or the like.

Alternatively, the hinging means (M) may comprise a pin that is revolvingly mounted in a housing. More precisely, with reference to Fig. 2, the fixed frame (1 ) comprises a base (1 1 ) that rests on the ground and two ending walls provided with a housing (51 ) obtained on the ending walls above the base (1 1 ).

The mobile frame (5) comprises two ending walls (50) from which two horizontal pins (10) protrude, being disposed along the horizontal hinging axis (Y). Each pin (10) is inserted in the housing (51 ) obtained on one of the two ending walls of the fixed frame (1 ). The pins (10) are faced one towards the other along the horizontal hinging axis (Y).

Alternatively, the pins can be connected to the fixed frame (1 ) and the housings can be obtained on the mobile frame.

Alternatively, the hinging means (M) may comprise only one pin disposed inside both housings.

The parts of the machine are mounted on the mobile frame (5). The assembly formed by the mobile frame and by the parts mounted thereon has a center of gravity. Preferably, the horizontal pins (10) are disposed in the center of gravity formed by the mobile frame and by the components mounted thereon.

The machine (100) comprises a conveyor belt (2) that revolves around two idler rolls connected to the mobile frame (5). The conveyor belt (2) defines a support surface (20) suitable for supporting and transporting the plate (T) from a loading area to an unloading area.

The conveyor belt (2) is connected to the mobile frame (5), and therefore a movement of the mobile frame (5) changes the position of the conveyor belt (2). More precisely, the mobile frame (5) can rotate around the horizontal hinging axis (Y) to go from a first position, wherein the support surface (20) of the conveyor belt (2) is horizontal in such a way as to support and transport the plate (L) in horizontal position, as shown in Fig. 3, to a second position, wherein the support surface (20) of the conveyor belt (2) is vertical, in such a way as to support and transport the plate (L) in vertical position, as shown in Fig. 4.

Advantageously, the machine (100) comprises actuation means (not shown in the figures) suitable for actuating the mobile frame (5) with respect to the fixed frame (1 ).

The actuation means may comprise a linear actuator. The linear actuator comprises a cylinder-piston assembly connected to the ending wall (50) of the mobile frame by means of a connecting rod-crank system, in such a way as to convert the rectilinear motion of the cylinder-piston assembly into a rotary motion of the ending wall (50) of the mobile frame (5).

The cylinder of the cylinder-piston assembly is connected to the base (1 1 ) of the fixed frame (1 ), and the connecting rod-crank system is connected to the mobile frame (5). In view of the above, the linear actuator moves the mobile frame (5) from the first position, which is shown in Fig. 3, to the second position, which is shown in Fig. 4.

Obviously, the actuation means may provide for a rotary motor that is connected to the mobile frame (5) either directly or by means of a transmission.

Advantageously, the machine (100) comprises locking means (not shown in the figures) that lock the mobile frame (5) in the first position and in the second position, preventing said mobile frame (5) from making any further movements.

The actuation means may provide for two stops that correspond to the first position and to the second position of the mobile frame. In such a case, the locking means may coincide with the stops of the actuation means. If the actuation means comprise a linear actuator with cylinder- piston assembly, by sliding in the cylinder, the piston goes from a first end- of-travel position, wherein the stem is almost completely retracted and the mobile frame (5) is in the first position, to a second end-of-travel position, wherein the stem is almost completely extracted and the mobile frame (5) is in the second position.

With reference to Figs. 2 to 4, the machine (100) comprises a bar (40) connected to the mobile frame (5) and having a longitudinal axis that is parallel to the horizontal hinging axis (Y). The bar (40) is disposed on the base (1 1 ) of the fixed frame (1 ) and is suitable for supporting a plurality of pressers (4). Each presser (4) comprises a roller (41 ) suitable for pushing the plate (L) against the support surface (20) of the conveyor belt (2). The rollers (41 ) are spaced from the support surface (20) of the conveyor belt (2), in such a way that a space is formed between the support surface (20) of the conveyor belt (2) and the rollers for the passing of the plate (L). The rollers are advantageously made of a soft material, such as rubber or polyurethane.

Advantageously, spring means (not shown in the figures) are disposed between the bar (40) and each roller (41 ) in such a way as to adjust the distance between the rollers (41 ) and the support surface (20) of the conveyor belt (2).

The bar (40) that supports the pressers (4) is connected to the mobile frame (5), and moves integrally with the mobile frame (5). More precisely, when the mobile frame (5) is in the first position, the pressers (4) are disposed on the support surface (20) of the conveyor belt (2), which is disposed in horizontal position, and push the plate (L) downwards, as shown in Fig. 3.

On the contrary, when the mobile frame (5) is in the second position, the pressers (4) are disposed on one side of the conveyor belt (2) and push the plate (L) against the support surface (20) of the conveyor belt (2), as shown in Fig. 4. In such a case, the pressers (4) push the plate (L) in such a way that the plate (L) is suspended above the base (1 1 ) of the fixed frame (1 )-

With reference to Figs. 2 to 4, the machine (100) comprises tool assemblies (3) supported by the mobile frame (5) in order to machine the edge of the plate (L). Each tool assembly (3) comprises a mandrel (30) provided with a rotating head (31 ) disposed near one side of the conveyor belt (2) in order to machine the edge of the plate (L). The rotating head (31 ) is shaped like a disc-shaped plate, such as for example an abrasive plate. The mandrel (30) rotates around its axis and the rotating head (31 ) is integral with the mandrel (30).

Each tool assembly (3) comprises an actuator (32) connected to the mandrel (30) to drive the mandrel (30) into rotation around its axis. In particular, the actuator (32) is an electrical motor provided with a shaft (33) connected to the mandrel (30) by means of transmission means (34). The shaft (33) of the electrical motor is parallel to the axis of the mandrel (30).

The transmission means (34) comprise a first toothed wheel (not shown in the figures) splined on the shaft (33) of the electrical motor, a second toothed wheel (not shown in the figures) splined on the mandrel (30) and a belt connected to the first toothed wheel and to the second toothed wheel. In view of the above, a rotation of the shaft (33) of the electrical motor corresponds to a rotation of the mandrel (30).

Advantageously, the electrical motor of the tool assembly (4) is housed in a container (35), in such a way as to prevent water infiltration during the machining of the plate (L). The container (35) is integral with the mobile frame (5). The container (35) comprises at least one hole for the shaft (33) of the electrical motor.

All tool assemblies (3) are connected by means of a connection element that is integral with the mobile frame (5). For example, the connection element may be a horizontal rod with ends connected to the walls (50) of the mobile frame (5).

Therefore, the tool assemblies (3) are connected to the mobile frame (5) and move together with the mobile frame (5). More precisely, when the mobile frame (5) is in the first position, as shown in Fig. 3, the electrical motor is disposed under the conveyor belt (2), in intermediate position between the conveyor belt (2) and the base (1 1 ) of the fixed frame (1 ). The mandrel (30) is disposed above the electrical motor, the shaft (33) of the electrical motor and the axis of the mandrel (30) are horizontal.

When the mobile frame (5) is in the second position, as shown in Fig. 4, the electrical motor is disposed on one side of the conveyor belt (2). The conveyor belt (2) is disposed between the electrical motor and the pressers (4). The mandrel (30) is disposed under the conveyor belt (2) to machine a lower edge of the plate (L). The shaft (33) of the electrical motor and the axis of the mandrel (30) are vertical.

Because of the provision of the transmission means (34), the arrangement of the tool assemblies can be compacted in such a way as to ensure a minimum volume of the machine and an easy movement of the mobile frame (5).

Because of the provision of a mobile frame (5) connected to the conveyor belt (2), to the tool assemblies (3) and to the pressers (4), the machine (100) of the invention can be used to machine both large-sized plates, positioning the mobile frame (5) in the first position, wherein the support surface (20) of the conveyor belt (2) is horizontal, and medium and small-sized plates, positioning the mobile frame (5) in the second position, wherein the support surface (20) of the conveyor belt (2) is vertical. The passage from the first position to the second position, or vice versa, of the mobile frame (5) is performed simply and rapidly by operating the actuation means in such a way as to permit a rotation of the mobile frame (5) relative to the fixed frame (1 ).