Patent Description:
More in detail, the invention relates to a sander machine for machining panels or similar pieces, in which a substantially flat surface and an opposite shaped surface, i.e. having a curvilinear profile, are defined.

Specifically, the sander machine at issue is intended for finishing, by sanding, the substantially flat surface of the panel or similar piece, in order to achieve a higher degree of planarity thereof.

The piece obtained by machining through means of the aforementioned sander machine can be used individually for subsequent machining, or coupled to another piece, also worked by the same sander machine, by overlapping and joining together the respective flat surfaces.

The pieces obtained by machining with the aforementioned sander machine can be used, for example, for making skis.

Documents <CIT> (on which the preamble of claim <NUM> is based), <CIT>, <CIT>, <CIT>, <CIT> and <CIT> are representative of the available art.

The object of the present invention is to provide a sander machine which is capable of effectively and precisely finishing the flat surface of a panel or similar piece in which a shaped surface opposite to said flat surface is defined.

Another object of the invention is to provide a sander machine that operates in such a way as to eliminate, or in any case reduce to a minimum, the risk of obtaining machined parts that do not conform to the desired characteristics.

A further object of the present invention is to provide a sander machine which is safe during its operation.

The present invention provides a sander machine in accordance with claim <NUM>. Advantageous features are provided in the dependent claims.

In the various figures the similar parts will be indicated with the same numerical references.

With reference to the attached <FIG> indicates as a whole a sander machine according to the present invention, for finishing, by sanding, a substantially flat surface of a panel P or other workpiece, in which a shaped surface is also defined (i.e., a surface with curvilinear profile) on the side opposite to said substantially flat surface.

Said sander machine <NUM> comprises a frame <NUM> and a cabin <NUM>, or a casing, mounted on said frame <NUM>.

An inlet <NUM> for the panels to be treated and an outlet <NUM> for the machined panels are defined in the cabin <NUM>.

Inside the cabin <NUM> there is an operating unit <NUM> for carrying out the required sanding operations on the panels.

In the sander machine <NUM> a first conveyor belt <NUM> is also provided for transporting the panel P to be treated from the inlet <NUM> to the operating unit <NUM>, along a direction of advancement A.

Above the first conveyor belt <NUM>, a first plurality of accompanying rollers <NUM> is provided, idle, to keep the panel P adhering to the same first conveyor belt <NUM> during its transport and accompany its movement from the inlet <NUM> to the operating unit <NUM>.

During the transportation by means of the first conveyor belt <NUM>, the panel P is arranged with its substantially flat lower surface L facing the underlying first conveyor belt <NUM>, and with its abutment upper surface U, shaped, facing the overlying first plurality of accompanying rollers <NUM>.

More specifically, each accompanying roller <NUM> is mounted on a respective pneumatic piston <NUM> oriented in such a way as to push the relative acceleration roller support <NUM> against the shaped upper surface U of the panel P, thus ensuring that the same panel P remains constantly adherent to the underlying first conveyor belt <NUM> during its way_towards the operating unit <NUM>.

The aforementioned operating unit <NUM>, arranged downstream of the first conveyor belt <NUM>, comprises instead a sanding roller <NUM>, with a horizontal axis, orthogonal to the advancing direction A, in which the upper end of the sanding roller <NUM> is substantially flush with, or coplanar with, the upper surface of the first conveyor belt <NUM>.

An abrasive surface is provided on the external surface of the sanding roller <NUM> to abrade or smooth the lower surface L of the panel P when the latter is passed over the sanding roller <NUM> itself.

In the sander machine <NUM> there are also motor means for setting the sanding roller <NUM> in rotation about its axis, for the execution of the planned sanding machining on the panel P.

The operating unit <NUM> also includes a abutment roller <NUM> arranged above the sanding roller <NUM> and idly rotatable around a respective axis of rotation, parallel to the axis of rotation of the sanding roller <NUM> itself.

Specifically, the respective axes of rotation of the abutment roller <NUM> and of the sanding roller <NUM> lie on a plane substantially orthogonal to the advancing direction A.

The abutment roller <NUM> is movable along a Z-axis, which is substantially orthogonal to the plane on which the panel P is made advance.

The sander machine <NUM> also comprises a control unit, capable of receiving and storing data and information relating to the shape, in particular the profile, of each panel P to be sanded.

For the movement of the abutment roller <NUM> along the Z-axis, on the other hand, movement means are provided, which are operatively connected to this control unit in such a way as to move the abutment roller <NUM> along said Z-axis according to the profile of the panel P, existing at any instant between the contact area between the sanding roller <NUM> and the panel P and the contact area between the latter and the abutment roller <NUM>, during the advancement of the panel P along the advancing direction A.

Therefore, the control unit commands, by means of the aforementioned moving means, the movement of the abutment roller <NUM> along the Z-axis as a function of the data stored therein, inherent to the shape or rather to the profile of the panel P being machined, and to the advancement speed of this panel P along the advancing direction A and/or to the position of the panel P along the advancing direction A.

The data relating to the advancement speed and the position of the panel P along the advancing direction A depend on the machining program to be carried out and can be directly stored in the control unit or detected by using suitable sensors configured to transmit the detected data to the control unit itself.

Between the first conveyor belt <NUM> and the sanding roller <NUM> there is a first lower support <NUM> adjustable in height and having a flat top surface which, during the operation of the sander machine <NUM>, is arranged at a slightly lower level than the top level of the sanding roller <NUM> and of the first conveyor belt <NUM>, to make it possible to remove material from the lower surface L of the panel P by the same sanding roller <NUM>.

Above the first lower support <NUM> there is a first pair of idle rollers <NUM>, individually movable along the Z-axis and associated, each, with a respective pneumatic system capable of keeping them constantly thrust towards the upper surface U of the panel P, so that the portion of the panel passing under said first pair of rollers <NUM> is kept pressed by the latter against the underlying first lower support <NUM> during the advancement of the panel P along the advancing direction A.

Downstream of the sanding roller <NUM> there is a second conveyor belt <NUM> to transport the machined panel P from the operating unit <NUM> to the outlet <NUM>; the top surfaces of the first conveyor belt <NUM> and of the second conveyor belt <NUM> being substantially at the same height according to said Z-axis.

Above the second conveyor belt <NUM> there is a second plurality of accompanying rollers <NUM>, idle, to keep the panel P adhering to the same second conveyor belt <NUM> during its transport and accompany its movement from the operating unit <NUM> towards the outlet <NUM>.

During the transport by means of the second conveyor belt <NUM>, the panel P is arranged with its lower surface L, machined, facing the underlying second conveyor belt <NUM>, and with the relative upper surface U facing the overlying second plurality of accompanying rollers <NUM>.

Furthermore, similarly to what has been described above, each roller of the second plurality of accompanying rollers <NUM> is mounted on a respective pneumatic piston <NUM>, oriented in such a way as to push the relative roller d the accompaniment <NUM> against the shaped upper surface U of the panel P, ensuring that the same panel P remains constantly adhering to the underlying second conveyor belt <NUM> during its journey towards the outlet <NUM>.

Between the sanding roller <NUM> and the second conveyor belt <NUM> there is a second lower support <NUM>, adjustable in height and having a flat top surface, which during the operation of the sander machine <NUM> is arranged at a slightly higher level than the top level of the first lower support <NUM>, to make it possible to remove material from the lower surface L of the panel P by the sanding roller <NUM>.

Above the second lower support <NUM> there is a second pair of idle rollers <NUM>, individually movable along the Z axis and associated each with a respective pneumatic system capable of maintaining them constantly pushing downwards, that is towards the upper surface U of the panel P at the outlet from the operating unit <NUM>, so that the portion of the panel passing under said second pair of rollers <NUM> is kept pressed by the latter against the underlying second lower support <NUM> during the advancement of the panel P along the advancing direction A.

When a panel P with a substantially flat lower surface L facing downwards and a shaped upper surface U facing upwards is inserted in the entrance <NUM> of the cabin <NUM>, the same panel P is transported towards the operating unit <NUM> from the first conveyor belt <NUM> with the aid of the first plurality of accompanying rollers <NUM>.

As the panel P advances in the advancing direction A passing through the operating unit <NUM> in the space between the sanding roller <NUM> and the abutment <NUM>, the latter is controlled by the aforementioned control unit to continuously raise and lower along the Z-axis according to the profile of the panel P present at any moment in the aforementioned space.

In this way it is obtained that the rotating sanding roller <NUM> can operate on the lower surface L of the panel P by removing from this only the protruding portions of material, thus allowing to obtain a surface with a higher degree of flatness.

The panel P, after being subjected to sanding in the operating unit <NUM>, passes over the second conveyor belt <NUM>, which carries it to the outlet <NUM> with the aid of the second plurality of accompanying rollers <NUM>.

The use of a spring or a fixed weight in place of the abutment roller <NUM>, and the relative movement system managed by the aforementioned control unit, would not have allowed the desired technical result to be obtained.

In fact, if a spring or a fixed weight were applied to the abutment roller <NUM> in such a way as to push it downwards, the latter would act by imparting to the panel P a force having an intensity proportional to the height of the profile of the panel P present at each instant in the space between the sanding roller <NUM> and the abutment roller <NUM>.

In this way, when between the sanding roller <NUM> and the abutment roller <NUM> there is a portion of panel P with a significant profile, the corresponding roller <NUM> should exert an excessive thrust force on the underlying panel P, which would produce, as an undesirable effect, an excessive removal of material by the sanding roller <NUM> with the consequent formation of depressions on the lower surface L of the panel P.

As can be seen from the above description, the sander machine according to the present invention allows to efficiently work a panel having a substantially larger surface and an opposite surface shaped in such a way as to be able to achieve a greater degree of planarity of this substantially flat surface and also the absence of defects in the same machined surface.

Claim 1:
Sander machine (<NUM>) for machining at least one panel (P) or workpiece, said panel (P) or workpiece comprising a first surface (L) which is substantially flat and a second surface (U), which is shaped, opposite said first surface (L), said sander machine (<NUM>) comprising:
first moving means (<NUM>) for moving, in use, said at least one panel (P) or workpiece to an operative zone according to an advancing direction (A);
sanding means (<NUM>) placed at said operative zone and configured to sand, in use, said first surface (L) of said at least one panel (P) or workpiece;
an abutment member (<NUM>) which is movable according to an axis (Z) being transversal to said advancing direction (A) and placed above said sanding means (<NUM>) such that when said at least one panel (P) or workpiece advance according to said advancing direction (A), said at least one panel (P) or workpiece pass through the space comprised between said sanding means (<NUM>) and said abutment member (<NUM>) with said first surface (L) facing said sanding means (<NUM>) and with said second surface (U) facing said abutment member (<NUM>); and
actuating means for moving said abutment member (<NUM>) along said axis (Z);
wherein the sander machine (<NUM>) is characterised in that it comprises:
a control unit which is configured to know advancing speed and/or position of said at least one panel (P) or workpiece along said advancing direction (A) and the profile of said at least one panel (P) or workpiece according to said axis (Z), which at any moments is between said sanding means (<NUM>) and said abutment member (<NUM>) when said at least one panel (P) or workpiece advance along said advancing direction (A); said control unit being operatively connected with said actuating means such that said control unit controls, by said actuating means, the movement of said abutment member (<NUM>) along said axis (Z) based on the advancing speed and/or the position of said at least one panel (P) or workpiece along said advancing direction (A), the value of said profile, such as to allow said sanding means (<NUM>) to sand, in use, said first surface (L) in such a way as to achieve a higher planarity level of the first surface (L).