Smoothing machine for wooden articles

Abstract

 The machine (12) enables flat surfaces (10S) of wooden articles (10), which are rough or to the surface of which one or more layers of coatings have been previously applied, to be smoothed and gauged. It comprises at least one smoothing-gauging unit (29), each smoothing-gauging unit (29) comprising at least one smoothing-gauging device (29.2, 29.2) and first means (34, 36, 18) for making each smoothing-gauging unit (29) approach and withdraw from that flat surface (10S) of the article (10) to be treated, together with second means (38) for moving each smoothing-gauging unit (29) relative to the article (10), parallel to that flat surface (10S) thereof (10) to be treated. Each smoothing-gauging device (29.1, 29.2) comprises a motorized smoothing-gauging element (28.1, 28.2) rotatable about an axis (30.1, 30.2) perpendicular to that flat surface (10S) of the article (10) to be treated. Each smoothing-gauging element (28.1, 28.2) presents a flat abrasive surface (43) facing the article (10) and parallel to that surface (10S) thereof (10) to be treated.

Description

[0001] The present invention relates to a machine per smoothing-gauging flat surfaces of rough wooden articles, or wooden articles to the surface of which one or more layers of various coatings have been previously applied (for example transparent varnish or paint). Articles of this type include for example wooden doors or wooden door panels for furniture, including in the form of a frame, which present flat surfaces, a face of an article also being able to present several flat surfaces lying in the same plane or in parallel planes, such surfaces being separated or bounded by recessed and/or relief profiles.

[0002] Smoothing-gauging machines are known for treating flat articles (such as doors or door panels), however these must not present said profiles, otherwise such machines cannot be used.

[0003] These machines comprise: a horizontal conveyor device (in particular a conveyor belt) for moving the articles to be smoothed-gauged, and a smoothing-gauging device or several smoothing-gauging devices disposed in succession above the conveyor device, each smoothing-gauging device being movable vertically in the two directions relative to the conveyor device. Each smoothing-gauging device comprises an externally abrasive flexible annular band mounted about at least three parallel horizontal rollers, of which at least one is motorized to slide the abrasive band along them. These rollers disposed perpendicular to the advancement direction of the conveyor device, and between two of these rollers (those of lower elevation) a means is provided which, from the interior of and through the abrasive band, exerts on the article transiting along the conveyor device local thrusts in restricted consecutive regions aligned parallel to the rollers, in order to obtain the same abrasive effect in all those article surface regions to be treated, independently of any planarity defects which the surface to be treated may present. Said pressing means consists essentially of a large number of electronically operated aligned vertical pistons (for example 48 or 60 in number) which thrust the relative abrasive band portion against the article surface.

[0004] Although these machines achieve good results, it will be apparent that they are very complicated and costly, and require constant and committed maintenance.

[0005] Another drawback is that, because of the way they are made, the aforedescribed smoothing-gauging machines are not able to treat articles presenting on one and the same face several flat surfaces which are coplanar but separated or bordered by relief profiles, and even more so if these surfaces are in parallel planes.

[0006] An object of the present invention is therefore to provide a smoothing-gauging machine which does not present these drawbacks, is decidedly simpler and less costly than the aforedescribed known machines, and enables all the flat surfaces present on a face of a wooden article to be treated, even if these surfaces lie in offset parallel planes and are separated or bordered by relief profiles.

[0007] This object is attained according to the present invention by a smoothing-gauging machine comprising at least one smoothing-gauging unit, each smoothing-gauging unit comprising at least one smoothing-gauging device and first means for making each unit approach and withdraw from the flat surface of the article to be treated, together with second means for moving each smoothing-gauging unit relative to the article, parallel to that flat surface to be treated;
characterised in that each smoothing-gauging device comprises a motorized smoothing-gauging element rotatable about an axis perpendicular to that flat surface of the article to be treated, each smoothing-gauging element presenting a flat abrasive surface facing the article and parallel to that surface thereof to be treated.

[0008] Specifically, the smoothing-gauging machine can be provided with means for maintaining the article fixed and means for moving each smoothing-gauging unit in the two directions perpendicular to the flat surface to be treated; or means for maintaining the smoothing-gauging unit fixed and for moving the article in the two directions perpendicular to the surface to be treated.

[0009] Likewise the smoothing-gauging machine can be provided with means for moving each smoothing-gauging unit parallel to the surface to be treated while maintaining the article fixed; or with means for maintaining the smoothing-gauging unit fixed while moving the article parallel to its surface to be treated.

[0010] From the aforegoing it will be apparent that the smoothing-gauging machine of the invention is decidedly simpler than known smoothing-gauging machines for wooden articles and can be produced at considerably lower cost than these.

[0011] In the simplest and convenient embodiment, each rotary smoothing-gauging element has a circular shape when viewed in plan, and in particular can be in the form of a disc, the abrasive surface of which, also preferably circular, being that facing the article to be treated. This does not mean that the smoothing-gauging element or the abrasive surface cannot have other than circular shapes, for example hexagonal or square, or even star shaped with a determined number of points, these points being rounded (as apparent hereinafter).

[0012] The smoothing-gauging element is preferably motorized by keying the element (for example in the form of a disc) onto the end of a motorized shaft perpendicular to its abrasive surface, the shaft extending from the face opposite that on which the abrasive surface is provided. The connection between the drive shaft and rotary smoothing-gauging element need not be rigid, hence allowing slight rocking, which in some cases can lead to better results.

[0013] The abrasive surface of the rotary smoothing-gauging element can be conveniently obtained by using an abrasive paper, of the type already used in the form of an abrasive band in known smoothing-gauging machines. If the rotary smoothing-gauging element is in the form of a disc, the shape of the sheet of abrasive paper will also be circular and of the same diameter as the disc. Instead of abrasive paper a layer or blanket of a suitable abrasive material can be used, for the material known by the brand name SCOTCH BRITE.

[0014] Conveniently, a rotary smoothing-gauging element comprises a rigid part provided with a flat face facing the surface to be treated, to this flat face there being fixed a layer of elastic material the outer face of which is made abrasive, for example by applying abrasive paper or a layer of said abrasive material thereto. The operation of applying the abrasive paper or layer of abrasive material, or their removal when they are to be replaced, is much facilitated if using for their application so-called hook and eye means such as those known by the brand name VELCRO.

[0015] The invention will be more apparent from the ensuing description of one embodiment thereof given by way of example. In this description reference is made to the accompanying drawings, in which:

Figure 1 is an elevational view of a smoothing-gauging machine of the invention, which is also provided with a conventional conveyor device (however not shown for simplicity), and having only one smoothing-gauging unit comprising a pair of devices with relative smoothing-gauging elements in disc form;

Figure 2 is a plan view thereof from above;

Figure 3 is an elevational view thereof in the direction of the arrow 3 of Figure 2;

Figure 4 is a perspective view of a disc-shaped rotary smoothing-gauging element provided with means for its quick connection to the relative operating shaft.

Figure 5 is a plan view of the abrasive surfaces of two smoothing-gauging elements of the same smoothing-gauging unit, the two smoothing-gauging elements being in the form of a five-point star with rounded points.

[0016] With reference to Figure 1, it has already been stated that the smoothing-gauging machine shown therein and indicated by 12 also comprises a conventional conveyor belt which is not shown in the figures, but which extends horizontally with its advancement direction perpendicular to the plane of the drawing, and serves mainly to bring into position an article, indicated by 10 (for example a wooden door panel of the type without relief profiles, shown schematically in the figure), the upper flat surface 10S of which is to be smoothed.

[0017] For simplicity reasons, Figure 1 does not shown the bed of the machine 12.

[0018] With regard to the articles to be smoothed it should be noted that although the article 10 has two preponderant dimensions compared with the third (that in the vertical direction), the present invention enables a smoothing-gauging machine to be provided able to treat a flat surface of a wooden article which is of any shape and of any ratio between its three dimensions.

[0019] It should also be noted that, although the flat article 10 appears horizontally disposed in Figures 1 and 3, the present invention enables a smoothing-gauging machine to be provided in which the article 10 is maintained vertical, or in any inclination, during machining.

[0020] Returning to the description of the smoothing-gauging machine 12, from Figures 1-3 it can be seen that it comprises a frame indicated overall by 14, carried by a bed not shown. The frame 14 comprises two lateral columns 16 along which two parallel horizontal connecting cross-members 18 rigidly move vertically, one for each side of the plane in which the two columns 16 lie. The two cross-members 18 also act as runways for a carriage 22 carrying a smoothing-gauging unit indicated overall by 29 and comprising, in the specific example, a pair of smoothing-gauging devices indicated by 29.11 and 29.2 and provided with relative rotary smoothing-gauging elements 28.1 and 28.2, of disc form in the specific example. However, depending on the articles to be treated and their specific requirements, a smoothing-gauging machine of the invention can be provided comprising a smoothing-gauging unit having a single smoothing-gauging device or more than two smoothing-gauging devices; and can also present more than one smoothing-gauging unit.

[0021] In case the surface to be treated is bounded by relief profiles having a plant shape with rounded edges, the diameter of at least one of the rotary smoothing-gauging elements 28.1 and 28.2 is conveniently selected such that its radius is the same as the curvature radius of the rounded edge. In the case of sharp edges there can be employed a smoothing-gauging element 28.1, 28.2 with the smallest diameter usable, whilst hand refining the non-treated parts of the edge surface at a later stage.
Also in this latter case the machine according to the invention offers an advantage in that by the soothing-gauging machines known in the art it was not possible to treat articles with relief profiles.

[0022] Returning to the machine 12, the rotary smoothing-gauging elements 28.1 and 28.2 are keyed onto the lower end of a relative vertical shaft driven by a corresponding gearmotor 32.1 and 32.2 respectively, the latter also supported by the carriage 22. Vertical movement of the pair of cross-members 18 and hence of the carriage 22, and consequently of the smoothing-gauging unit 29, is achieved by a conventional mechanism comprising a gearmotor 34 driving a horizontal shaft 36 which operates two vertical screws (not shown in the figs for simplicity), one at each of the two columns 16 and cooperating with respective lead nuts (also not shown) each fixed to a corresponding connection element 20 of the relative end of the pair of cross-members 18. Consequently, by operating the gearmotor 34 the pair of cross-members 18 can be raised or lowered while maintaining them perfectly horizontal. The connection element 20 on the right of Figure 1 also carries a second gearmotor 38 operating a conventional male-female screw combination (not shown) enabling the carriage 22 to be moved transversely in the two directions along the pair of cross-members 18.

[0023] The disc-shaped smoothing-gauging elements 28.1 and 28.2 comprise in this specific example (best seen by observing the discoidal smoothing-gauging element 28 shown enlarged in Figure 4) a rigid support disc (for example of steel) and a disc-shaped layer of elastic material 42 (for example a spongy rubber), applied (for example glued) thereto on the lower face of the rigid disc 40. As already stated, there can be applied to the lower face of the elastic layer 42 a circular sheet of abrasive paper of substantially the same shape as this latter, or a circular blanket of abrasive material, both (as already stated) being conveniently applied using means which allow its quick application and removal (in particular the means known by the brand name VELCRO).

[0024] The discoidal smoothing-gauging element 28 of Figure 4 is conveniently fixable coaxially to the lower end of the operating shaft 30 by self-centering quick connection means, comprising in the specific example three male elements 44 fixed to the shaft 30, parallel thereto, by a round plate 47. As can be seen from Figure 4, the male elements 44 are positioned at the vertices of an equilateral triangle centered about the shaft 30. Each male element 44 engages a corresponding female element 46 fixed in corresponding positions on the upper face of the rigid disc 40. The female elements 46 are provided with a flared mouth for self-centering and with means for snap-retention (not visible, but of conventional type) of the relative male element 44 when this latter is forced into the female element 46. For its release, a force in the opposite direction has to be applied. These quick connection means are evidently similar to those used in compressed air hoses.

[0025] For certain machining operations it can be useful to provide between the drive shaft 30 and the smoothing-gauging element 28 a joint (for example a universal joint) enabling the element 28 to rotate slightly about a plane perpendicular to the shaft 30. With reference to Figure 4, said joint is provided just above the round plate 47.

[0026] As already stated, the rotary smoothing-gauging elements can have a plan shape other than circular (for example in the form of a regular polygon), although for certain embodiments it could be convenient to use particular shapes. For example, two rotary smoothing-gauging elements 28A.1 and 28A.2, shown flat in Figure 5, are star shaped with rounded points. This specific shape enables just one of the two to be rotated using a single gearmotor, the rotation of the other element, which is idle, being a consequence of the rotation of the first. The smoothing-gauging machine 12 is conveniently provided with a control unit of the conventional type, preferably of microprocessor type, for controlling and programming machine operation on the basis of the articles to be treated, so as to optimise its use.

[0027] With reference to Figures 1-3, the operation of the smoothing-gauging machine shown therein is described hereinafter, although this operation should already be apparent from the aforegoing.

[0028] The machine 12 also comprises (as already stated) a horizontal conveyor belt extending in a direction perpendicular to the plane of the sheet containing Figure 1, and enabling the article 10 to be located in the position for treating its upper surface 10S. During this stage the smoothing-gauging unit 29 is located at a height (greater than that shown in Figures 1 and 3) such as not to constitute an obstacle to the positioning of the article 10 by driving the conveyor belt. By suitably operating the gearmotors 34 and 38 the carriage 22 can be positioned such that the smoothing-gauging unit 29 is firstly positioned vertically above the machining commencement position, after which it is lowered to bring the abrasive surface of the rotary smoothing-gauging elements 28.1 and 28.2 in contact with that surface 10S of the article 10 to be treated. At this point or, better, just previously, the gearmotors 32.1 and 32.2 are operated so that the rotary smoothing-gauging elements 28.2 and 28.2 enter into action. By suitably combining (for which said control unit is very useful) the movement of the conveyor belt and the movement of the carriage 22 along the pair of cross-members 18, the entire upper surface 10S of the article 10 can be swept, or just a part thereof, this being useful if a face of the article presents several surfaces disposed in parallel planes or separated and/or bordered by relief profiles.

[0029] During the smoothing-gauging operation, by suitably choosing the speed of movement of the conveyor belt and carriage 22 and the speed of rotation (for example by potentiometer) of the rotary smoothing-gauging elements 28.1 and 28.2, and by choosing the most suitable abrasive material (in particular the grain size of the abrasive paper or the type of abrasive blanket), smoothing-gauging results can be obtained (after some experience) which are not only comparable to those of the best known smoothing-gauging machines, but are decidedly better and at low cost.

[0030] The smoothing-gauging machine can be conveniently provided with sensors connected to control unit to sense the entry and exit of an article, and if required even its geometrical characteristics, this enabling the smoothing-gauging operation on an article to be automated to the maximum extent by suitably programming the control unit.

[0031] Although within the smoothing-gauging machine 12 the carriage 22 carrying the smoothing-gauging unit 29 can move only transversely (along the pair of cross-members 18), so that movement of the article 10 in a direction perpendicular to the preceding is achieved by the conveyor belt (not shown), a smoothing-gauging machine could evidently be provided in which the article, once brought to the machine, is maintained fixed and conventional means are provided to also move the carriage horizontally in the direction perpendicular to that of the cross-members 18.

[0032] It is also evidently possible to provide a smoothing-gauging machine according to the invention in which the smoothing-gauging unit is maintained fixed and conventional means be provided to move the article both vertically and horizontally in two perpendicular directions, so effecting the smoothing-gauging operation over the entire surface of the article which is to be treated.

[0033] The smoothing-gauging machine of the invention can also be provided with additional sanding devices in the form of a rotary cylindrical brush rotatable about its axis, of the type described in Italian patent 1284081 and used in the sanding machine described in EP-A-1332833. As known to the expert of the art, these brush sanding means present filiform flexible elements extending substantially radially from a coaxial shaft and are grouped in angularly equidistant rows normally parallel to the shaft axis, there being interposed between the rows of filiform elements flexible abrasive sheets the far edge of which projects beyond the free end of the filiform elements, whereas the near edge of these sheets is fixed to the shaft, each abrasive sheet being cut into outwardly extending strips.

[0034] These additional sanding means of cylindrical brush form can be useful for better preparation for smoothing-gauging and/or a more precise finish after this operation.

Claims

1. A machine (12) per smoothing-gauging flat surfaces (10S) of wooden articles (10) which are rough or to the surface of which one or more layers of coatings have been previously applied, comprising at least one smoothing-gauging unit (29), each smoothing-gauging unit (29) comprising at least one smoothing-gauging device (29.1, 29.2) and first means (34, 36, 18) for making each smoothing-gauging unit (29) approach and withdraw from that flat surface (10S) of the article (10) to be treated, together with second means (38) for moving each smoothing-gauging unit (29) relative to the article (10), parallel to that flat surface (10S) thereof (10) to be treated;
characterised in that each smoothing-gauging device (29.1, 29.2) comprises a motorized smoothing-gauging element (28.1, 28.2) rotatable about an axis (30.1, 30.2) perpendicular to that flat surface (10S) of the article (10) to be treated, each smoothing-gauging element (28.1, 28.2) presenting a flat abrasive surface (43) facing the article (10) and parallel to that surface (10S) thereof (10) to be treated.

2. A smoothing-gauging machine (12) as claimed in claim 1, wherein the second means (38) enable each smoothing-gauging unit (29) to be moved parallel to that surface (10S) of the article (10) to be treated, this latter (10) being maintained fixed.

3. A smoothing-gauging machine (12) as claimed in claim 1, wherein the first means (34, 36, 18) for maintaining the article (10) fixed and means (38) enable each smoothing-gauging unit (29) to be moved perpendicular to that surface (10S) of the article (10) to be treated, this latter (10) being maintained fixed.

4. A smoothing-gauging machine (12) as claimed in claim 1, wherein each rotary smoothing-gauging element (28.1, 28.2) is of circular plan shape.

5. A smoothing-gauging machine (12) as claimed in claim 1, wherein each rotary smoothing-gauging element (28.1, 28.2) is keyed onto the lower end of an operating shaft (30.1, 30.2) which extends, perpendicular to the abrasive surface (43) of the smoothing-gauging element (28.1, 28.2), from that side opposite the abrasive surface (43).

6. A smoothing-gauging machine (12) as claimed in claim 1, wherein a rotary smoothing-gauging element (28) comprises a rigid part (40) provided with a flat face facing that article surface (10) to be treated, to said flat face there being fixed a layer of elastic material (42), the outer face (43) of which presents an abrasive surface.

7. A smoothing-gauging machine (12) as claimed in claim 1, wherein the abrasive surface of a rotary smoothing-gauging element (28) is obtained by applying an abrasive paper (43) or a layer or blanket of abrasive material.

8. A smoothing-gauging machine (12) as claimed in claim 7, wherein the abrasive paper (43) or the layer or blanket of abrasive material are applied to the relevant part of the rotary smoothing-gauging element (28) using hook and eye means.

9. A smoothing-gauging machine (12) as claimed in claim 5, wherein the rotary smoothing-gauging element (28) is fixable to the relative end of the operating shaft (30) by self-centering quick connection means (44, 46).

10. A smoothing-gauging machine (12) as claimed in claim 9, wherein the quick connection means comprise three male elements (44) fixed to the shaft 30 and parallel thereto (30), and positioned at the vertices of an equilateral triangle centered about the shaft (30), the male elements (44) engaging corresponding female elements (46) fixed in corresponding positions on that face of the smoothing-gauging element (28) facing the shaft (30), and provided with a flared mouth for self-centering and with means for snap-retention of the relative male element (44) when this latter is forced into the female element (46), an opposite force enabling its release.

11. A smoothing-gauging machine (12) as claimed in claim 5, wherein a joint is provided between an operating shaft (30) and the relative rotary smoothing-gauging element (28) to enable this latter to be slightly inclined to a plane perpendicular to the shaft (30), in order to better follow the surface (10S) to be treated.

12. A smoothing-gauging machine (12) as claimed in claim 1, provided with a smoothing-gauging unit (29) having a motorized rotary smoothing-gauging element (28A.1) with a plan shape in the form of a star with rounded points, the smoothing-gauging element (28A.1) engaging laterally with one (28A.2) or more idle smoothing-gauging elements which are hence operated by the first smoothing-gauging element (28A.1).

Drawing