ES2258132T3 - METHOD AND APPARATUS FOR SANDING PROFILED FLAT ITEMS. - Google Patents

Abstract

A method for sanding flat wooden articles (10) having recessed or embossed shapes, comprising the following steps: a) sanding the article (10) with a first sanding unit (20) comprising first cylindrical sanding means ( 20.1, 20.2) superimposed on the article (10) to be sanded and that move horizontally in a certain direction of advance (16), rotating the first sanding means (20.1, 20.2) around its axes, which are horizontal, the first sanding means being movable horizontally in a direction perpendicular to the direction of advance (16); b) sanding the entire upper surface of the article (10), including the recessed interior surfaces (10.5) and the vertical parts (10.1 and 10.2), by means of a second sanding unit (32) comprising second means of

Description

Method and apparatus for sanding flat items profiled

The present invention relates to a method for sanding flat wooden articles that have reduced shapes or in relief, including framed items. The invention is also refers to a machine to perform the method.

Items of the type mentioned above include, for example, the door panels of units of wooden kitchen furniture, wooden window frames and Even doors in particular.

Known sanding machines include:

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         a horizontal conveyor belt on which the items to be sanded in the so-called address of Advance;

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         a sanding unit superimposed on the conveyor belt that it comprises at least one cylindrical sanding means of rotation axis horizontal that extends transversely to the direction of advance, each sanding means of said unit being adjustable in elevation; Y

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         another sanding unit superimposed on the conveyor belt and that comprises at least one cylindrical shaft sanding means horizontally extending substantially in the direction of advance, each sanding means of the second unit having a length equal to at least the width of the article to be sanded, being lift adjustable and movable horizontally in both senses in a direction substantially transverse to the direction forward. Said machine, for sanding flat wooden articles, which include embossed formations, described in the document U.S.-A-5733180.

As is known to a person skilled in the art, The cylindrical sanding means mentioned above consist of essentially in the so-called rotating cylindrical "brush" around its own axis, in which the filiform elements of the brush extend substantially radially from a coaxial tree and are grouped in two rows normally parallel to the axis of the tree and angularly equidistant. Be interpose sheets of abrasive fabric between rows of elements filiforms that have their far edge protruding beyond the free end of filiform elements, the proximal edge being of those sheets fixed to the tree of the cylindrical sanding element. With the exception of its innermost part, which allows them to be fixed to the relative tree, each sheet of abrasive fabric is cut in strips of equal width (for example, 5 mm) that extend towards outside, allowing this to be abrasive tissue, due to the presence of filiform elements, adapt to the forms of item to be sanded.

Improved means of this type have been described in Italian patent application MI96A 001313, of which the inventor of the present application is owner and inventor.

As is well known to an expert in technique, due precisely to the fact that flat items to be sanded have shapes, known sanding machines described above do not offer satisfactory results, mainly because the sanding means attack the corners of edge present in the article, and may be damaged by they.

Despite this serious inconvenience, these machines are widely used, with nothing better in the market, except, obviously, manual sanding which, however, for reasons of cost, cannot possibly be used now, except only for sanding the edges of the article (as in reality), since these are not sanded by said machine and in any case constitute a fairly small part of the total surface of the article
sanding

Before proceeding, for reasons of clarity, define with reference to Figure 1 the terminology related to a item to be sanded. This shows an isometric view of a generic rectangular wooden article 10 (for example a panel of door of a furniture unit or a real door). How can seen in this figure, article 10 comprises two pieces lateral vertical, parallel, 10.1 and 10.2 and two pieces end transverse 10.3 and 10.4. It is noteworthy that, if the article is quite long, one or more may also be present intermediate cross pieces (which, for simplicity, are not shown in the example of Figure 1).

The four elements 10.1, 10.2, 10.3 and 10.4 of the Article 10 essentially form a peripheral frame surrounding its inner part. This internal part comprises a recessed region 10.5, also in the form of a frame, adjacent to said frame exterior, and a raised central region, rectangular 10.6, which in this specific example has an equal elevation (but also could be different) than the outer frame 10.1, 10.2, 10.3 and 10.4 It should be noted that the longitudinal direction of the article 10 (in which the vertical pieces 10.1 and 10.2 extend) matches your direction of advance when moved by the conveyor of the sander machine, so that cross pieces 10.3 and 10.4 extend in one direction perpendicular to the direction of advance.

Having stated this, the object of the invention present is to obviate the above mentioned inconveniences of the machines known sanders, providing a method for sanding items of wood of the aforementioned type, and a machine for its Sanding with this method.

The above mentioned objective is achieved with a sanding method according to claim 1 attached.

To get a better finish of the article after step c) of the claims, the Next step, consisting of:

d)

finish sanding done by a fourth sanding unit comprising middle sanding rooms analogous to the third sanding means used in step c), but softer (that is, with more flexible filiform elements and with an abrasive or finer grain fabric).

The sanding method mentioned above allows sanding quality to be obtained than sander machines acquaintances are totally unable to provide.

It should be noted that it is not essential that the step a) precede step b), since the temporal order of the two Steps is not critical. To prevent sanding by hand the longitudinal edge of the article, the method of the invention comprises conveniently an additional step of:

and)

sand those edges of the article parallel to the direction of advance by means of a fifth sanding unit comprising at least one pair of fifth cylindrical sanding media, placing every fifth Sanding means of each pair on one side of the article that moves in the forward direction to interfere with a longitudinal edge of the latter, having the two sanding means of each pair their rotation axes contained in a vertical plane perpendicular to the direction of advance and forming symmetrically with the vertical a angle that can be varied between 0 and 30 degrees.

Preferably, in addition to the turning speed of the third sanding means, the turning speed of all Other sanding means can also be varied within limits determined, but (in contrast to said third media) kept constant during the machining of one and the same article, so that the speed of rotation can be adjusted according to the particular typology and / or the type of wood of the article to be sanding

The invention also relates to a machine of sand to perform the method described above. This machine It has the features described in claim 5.

To get an even better finish than article, the machine described above in terms of its essential features can comprise a fourth unit sander comprising fourth cylindrical sanding means analogous to the third means of sanding, but softer.

The machine may also be provided with a fifth sander unit comprising at least a couple of fifths cylindrical sanding means, placing every fifth means of sanding each pair on one side of the article in transit to interfere with a longitudinal edge of the latter, having the two sanding means of each pair its axes of rotation contained in a vertical plane perpendicular to the direction of advance and forming symmetrically with the vertical an angle that can be varied between 0 and 30 degrees.

As previously stated with reference to the method of the invention, in addition to providing means for varying the speed of rotation of the third means of sanding the machine, it they can conveniently provide means to vary also, within certain limits, the turning speed of all other means sanding, to allow their turning speeds to be adjusted according to the particular typology and / or type of wood of the item to be sanded.

The invention will be better understood by following description of an embodiment of a sander machine according to the invention, which performs the method of the invention. In this description refers to the accompanying figures, from 2 to 6, in which:

Figure 2 is a schematic view in perspective of a machine according to the present invention;

Figure 3 is a schematic view in perspective showing how the fifth sanding means operate;

Figure 4 is a schematic view in perspective showing how the first sanding means operate;

Figure 5 is a schematic view in perspective showing how the second sanding means operate;

Figure 6 is a vertical longitudinal section through along line 6-6 of Figure 5;

Figure 7 is a schematic view in perspective showing how the third and fourth means of sanding

As can be seen in Figure 2, the machine for sanding items of the type initially reviewed (for example, the Article 10 of Figure 1) is indicated in conjunction with 12. The machine 12 comprises conveyor means, which consist of the specific example illustrated on a conveyor belt (but it could also be another type of conveyor means, for example a roller table). The two branches 14 of the media Conveyors are shown only partially in Figure 2 to simplify. The items to be sanded (not shown in Figure 2 for simplify) rest in succession on the upper branch and move forward in conjunction with the upper branch in the direction of arrow 16, which here indicates the sense of progress of articles 10. Consequently, in the specific example illustrated in Figure 2, the article, which advances in the direction of arrow 16, finds firstly what has been previously defined as fifth sanding unit 18, which in this case comprises a single pair of fifth cylindrical sanding means, indicated in Figure 2 with 18.1 and 18.2 (see also Figure 3). As already mentioned previously, the latter have their axes of rotation 24.1 and 24.2 contained in a vertical plane perpendicular to the direction of feed 16 and are tiltable with respect to the vertical of this plane in An angle between 0 and 30 degrees (as indicated by arrows 26.1 and 26.2 of Figure 3). This can be useful to get the best sanding result if the longitudinal edges of the article do not They are vertical or profiled. The article passes between the pair of fifth sanding means 18.1 and 18.2, each interfering with one of the two longitudinal sides of article 10. The distance between the two fifth fifths of sanding 18.1 and 18.2 is adjusted previously in such a way that once they turn, they rub the edges longitudinal sections of Article 10. Regarding this In particular, it can be seen in Figure 3 that the machine 12 comprises reference guides 28.1 and 28.2 that allow the pair of fifths Sanding means 18.1 and 18.2 be located exactly in accordance with the width of article 10. The speed of rotation of the fifths Sanding means 18.1 and 18.2 can be varied by an inverter and corresponding potentiometer provided on a control panel (no shown to simplify) of the machine 12.

It is important, however, to keep in mind that the fifth fifth sanding means 18.1 and 18.2 could be dispensed with (in in which case the longitudinal edges of the article must be sanded manually, as with transverse edges). The fifth means may also be located inside the machine 12 in a position different from that shown in Figure 2.

Continuing on its advance along the machine 12, article 10 finds the one previously defined as the first sander unit 20, which in this specific example it comprises two first cylindrical sanding means, indicated with 20.1 and 20.2 (Figures 2 and 4), whose axes of rotation are horizontal and are inclined with respect to the direction of travel 16 at an angle It can vary between 0 and 30 degrees. The purpose of this is to obtain, according to the specific article to be sanded, a softer impact on any relief or internal shape of the article, which however should only stand out slightly (no more 5 mm). As can be seen, the sanding means 20.1 are arranged more downstream than sanding means 20.2, so that there is no interference between the two as a result of their alternative movement in the horizontal direction, transverse to the feed direction 16 (as indicated by double arrow 22). From again, in this case the speed of rotation of the first two means sanding 20.1 and 20.2 (which rotate in the opposite direction, as indicated with the respective arrows 30.1 and 30.2) it can be varied by a inverter with a potentiometer located on the control panel of the machine 12.

As already mentioned, the movement alternative of the first two sanding media 20.1 and 20.2 of according to the double arrow 22, it has a travel range of work that is determined by the position of said guides position 28.1 and 28.2, so that the sanding means 20.1 and 20.2 they include in practice only the transverse pieces 10.3 and 10.4 and the inner flat surface 10.6 of article 10 (Figure one). The route can also be adjusted by regulators (not shown to simplify) located in the fifth sanding media 18.1 and 18.2 so that the first sanding means 20.1 and 20.2 do not even interfere with the inner corners of the pieces vertical 10.1 and 10.2.

Article 10 finds below the second sander unit 32, comprising in the illustrated example specific two second cylindrical sanding means, located in sequence and indicated with 32.1 and 32.2 (Figures 2, 5 and 6). They turn around their axes in opposite directions (as indicated by the arrows 36.1 and 36.2) and are movable in both directions in the direction vertical (as indicated by double arrows 34.1 and 34.2). This allows the inner surface 10.5 to be sanded, with frame shape (Figure 1) of article 10 to be sanded. From according to this, as shown in Figure 6, upon arrival of Article 10, each of the second sanding means 32.1 and 32.2 it is raised so as not to interfere with the upper front corner 10.8 of Article 10, being downloaded below to allow it to be sanded the surface 10.5.

The devices (not shown due to being conventional type) to raise and lower the second sanding means 32.1 and 32.2, include pneumatic cylinders controlled by solenoid valves operated electronically by a sensor located at the entrance of the machine 12, to transmit to a unit central (not shown to simplify, but with which the machine 12 is provided) the distance between the beginning and the end of article and the width of the cross pieces of article 10. Again in this case, the speed of rotation of the sanding means seconds 32.1 and 32.2 can be varied by an inverter and potentiometer located on the machine control panel 12.

Article 10 finds below said third sanding unit 38, which comprises in the specific example third cylindrical sanding means 38 (Figure 7) that can rotate around its horizontal axis at a speed that can be varied (as in the preceding cases), this perpendicular being shaft to the direction of travel 16. Sanding means 38 allow sanding of surfaces of article 10 that have not been sanded still, while at the same time also refine those others article surfaces that have substantially the same elevation (10.1, 10.2, 10.3 10.4 and 10.6). Like those surfaces may present small reliefs (although not shown, for simplify, in the case of article 10), it prevents them from being damaged (so as not to compromise the sanding result) through the provision of conventional devices that allow the speed of rotation of sanding means 38 is reduced (even 30%) when interferes with these reliefs.

In the case of machine 12, to obtain a sanding of superior quality, a fourth unit of sanding 40, comprising in this specific example means of 40 single cylindrical sanding. The latter differ from third parties sanding means 38 just for being "softer" (in the sense mentioned above), but otherwise they operate from it way.

As already mentioned, machine 12 is conveniently provided with a conventional control unit (not shown to simplify), preferably of the type of microprocessor, which allows its operation to be controlled, aided by the presence of sensors provided, for example, to measure the distance between the vertical pieces of the article to automatically determine the path of the first means of sanding 20.1 and 20.2, to detect the presence of corners transverse and raise and lower the second sanding means 32.1 and 32.2 to prevent these corners from being damaged, to vary the speed of the various sanding means and in particular for decrease the speed of third media 38 and when correspond to possible projections, and to tilt the axes of rotation of the sanding means according to the type of article That has to be sanded.

Claims (10)

1. A method for sanding wooden items planes (10) that have reduced or raised shapes, which They comprise the following steps:

to)

     sand the article (10) with a first sanding unit (20) that comprises first cylindrical sanding means (20.1, 20.2) superimposed on article (10) to be sanded and move horizontally in a certain direction of advance (16), rotating the first sanding means (20.1, 20.2) around of its axes, which are horizontal, the first being movable sanding means horizontally in a direction perpendicular to the forward direction (16);

b)

     sand the entire upper surface of the article (10), including recessed interior surfaces (10.5) and vertical parts (10.1 and 10.2), by means of a second sanding unit (32) that comprises second cylindrical sanding means (32.1, 32.2) superimposed on the article (10) that moves in the direction of feed (16), the second sanding means (32.1, 32.2) having a length at least equal to the width of the article (10) and rotating around its own axis that is horizontal and perpendicular to the forward direction (16);

characterized because

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         the axis of the first cylindrical sanding means (20.1, 20.2) forms an angle less than or equal to 30 degrees with the direction of advance (16), being chosen the route of the first means of cylindrical sanding (20.1, 20.2) to sand only the parts cross sections (10.3, 10.4) and internal surfaces (10.6) of the article (10) that have an elevation equal or only slightly different from that of the cross pieces (10.3, 10.4);

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         the second sanding means being movable vertically (32.1, 32.2) in both directions to be elevated and prevent interfere with the cross corners (10.8) of the article (10);

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         one more step is planned consisting of

C)

     sand the entire upper surface of the article (10), including any relief that has a slightly greater elevation than cross pieces (10.3, 10.4) and vertical pieces (10.1, 10.2), with a third sanding unit (38) comprising third parties cylindrical sanding means (38) superimposed on the article (10), the third sanding means (38) having a length at least equal to the width of the article (10) and rotating at a speed selectively variable around its own axis so that the speed of rotation of these sanding means (38) can be reduced when the reliefs of the article (10) are in correspondence with they, to prevent damage to the reliefs, being horizontal the axes of the third sanding means (38) and forming an angle 90-70 degrees with forward direction (16).

2. A method as claimed in the claim 1, wherein after step c) a Additional step consisting of:

d)

finish sanding done by a fourth sanding unit comprising middle sanding rooms (40) analogous to the third sanding means (38) used in step c), but softer.

3. A method as claimed in the claim 1, wherein an additional step is provided that consists in:

and)

sand those axes of the article parallel to the direction of advancement with a fifth sanding unit (18) comprising at least one pair of fifth cylindrical sanding media (18.1, 18.2), each fifth fifth sanding (18.1, 18.2) of each pair on one side of the article (10) moving in the forward direction (16) to interfere with a longitudinal edge of the latter (10), having the two sanding means (18.1, 18.2) of each pair their axes of rotation (24.1, 24.2) contained in a vertical plane perpendicular to the direction of advance (16) and forming symmetrically with the vertical An angle that can be varied between 0 and 30 degrees.

4. A method as claimed in the claim 1, wherein the speed of rotation of said means of sanding other than the third sanding means is varied between certain limits, but is kept constant during the mechanization of the same article (10). 5. A machine (12) for sanding articles of flat wood (10) with recessed or raised shapes, which understands:

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a transport device (14) to make the articles (10) to those who are sanding move horizontally, in succession, in a forward direction (16), in correspondence with a series of sanding units (20, 32, 38);

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a first sanding unit (20) comprising first means of cylindrical sanding (20.1, 20.2) superimposed on the articles (10) that move on the conveyor device (14), being able to turn the first sanding means (20.1, 20.2) around their axes that are arranged horizontally, the movable ones being first sanding means (20.1, 20.2) in one direction perpendicular to the direction of advance (16);

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a second sanding unit (32) comprising second means of cylindrical sanding (32.1, 32.2) superimposed on article (10) that it travels on the conveyor device (14), having the second sanding means (32.1, 32.2) a length at least equal to the width of the article (10) and that can rotate around its own axes that are horizontal and perpendicular to the direction forward (16);

which is characterized because:

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the shafts of the first cylindrical sanding means (20.1, 20.2) they form an angle less than or equal to 30 degrees with the direction of advance (16), means (28.1, 28.2) are provided to limit the path of the first sanding means (20.1, 20.2) for sanding only cross pieces (10.3, 10.4) and surfaces interiors (10.6) of article (10) having an equal elevation or only slightly different from the elevation of the pieces transversal (10.3, 10.4);

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there is intended means for moving the second sanding means (32.1, 32.2) vertically in both directions (34.1, 34.2) to raise them (32.1, 32.2) and prevent them from interfering with the corners cross sections (10.8) of article (10);

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is A third sander unit (38) is provided, comprising third parties cylindrical sanding means (38), superimposed on the article (10), the third sanding means (38) having a length at least equal to the width of the article (10) and being able to rotate to selectively variable speed around its own axis horizontal, which forms an angle of 90-70 degrees with the forward direction (16), to reduce the turning speed of the third sanding means (38) when in correspondence With the reliefs.

6. A machine (12) as claimed in the claim 5, wherein a fourth unit of sanding (40) comprising quarter cylindrical sanding means (40), analogous to the third sanding means (38), but softer. 7. A machine (12) as claimed in claim 5, wherein a fifth sanding unit (18) is provided comprising at least a pair of fifth cylindrical sanding means (18.1, 18.2), each fifth fifth being located of cylindrical sanding (18.1, 18.2) of each pair to one side of the article (10) to interfere with the longitudinal edge of the latter (10), the two sanding means (18.1, 18.2) of each pair having their axis of rotation (24.1, 24.2) contained in a vertical plane perpendicular to the direction of advance (16) and symmetrically forming an angle with the vertical that can be varied between 0 and 30
degrees. 8. A machine (12) as claimed in the claim 5, wherein, in addition to comprising means for varying the speed of rotation of the third sanding means (38) of the machine, means are provided to vary also, within limits determined, the turning speed of all other means of sanding 9. A machine (12) as claimed in the claim 7, wherein the fifth sanding unit (18) is arranged upstream of the other sanding units. 10. A machine (12) as claimed in the claim 9, wherein the first sanding unit (20) is arranged upstream of the second sanding unit (32), being the latter arranged upstream of the third and fourth units sanding (38, 40).