Apparatus for automatically feeding and applying thin metallic film gilding leafs in a system for coating wooden strips for frames and other

Abstract

 For arranging and applying a sequence of gilding leafs on a strip, or strips, advancing in the machine, the apparatus comprises a pervious, aspirating conveyor belt (12) which is subjected to vacuum by means of pervious walls of suction boxes (20, 22) along the active branch for conveying the gilding leafs (D) to a free cylinder (18) after which the belt is made to skim the surface of the strip, or strips (L) on which glue was applied, to arrange and stick the so-called imitation gold leaf (D) with at least one contoured, elastic pressure roller (34); the gilding leafs (D) are fed onto the conveyor belt (12) by means of a mechanical hand (32) which picks the leafs from a reservoir (30).

Description

[0001] The invention relates to an apparatus to be combined to a system for coating strips for frames or other with gilding leafs formed by an extremely thin metallic film. The apparatus permits this operation avoiding the costly intervention of highly specialized manual operators, who until now performed this operation by arranging a number of leafs on a strip, or several strips, advancing for this purpose on a roller conveyor.

[0002] The apparatus herein - for automatically feeding and applying said gilding leafs along an advancement path of the strips, in a system of the type mentioned above - essentially comprises: a pervious conveyor belt subjected to vacuum - by means of pervious walls of suction boxes - along the active branch for transporting the leafs to a free cylinder, after which the belt skims the surface of the strip, or strips, on which glue is applied whereby laying the leaf; at least one contoured, elastic pressure roller to make the gilding leafs, fed in sequence by the conveyor belt (12), adhere to the strip, or strips, said conveyor belt being entrained around said pressure roller; and means for continuously arranging a sequence of leafs on said conveyor belt.

[0003] Advantageously, walls - which are also flexible - can be arranged along the path of the conveyor belt and the gilding leafs between said transmission cylinder and the pressure roller; a slight vacuum is created between the walls to accompany the gilding leafs until they are arranged on the transiting strip, or strips.

[0004] The apparatus may also comprise at least one second pressure roller, which acts in sequence on the surface of the strip or strips already covered with the gilding leafs.

[0005] The pressure roller, or rollers, are adjustable with respect to the strip guides, to adapt them to the shape of the strips.

[0006] The apparatus can advantageously comprise the following means for arranging the sequence of gilding leafs on the conveyor belt: a reservoir containing a stack of said leafs; a mechanical hand providing alternating movement and equipped with a transversal suction tube with a set of holes for picking and lifting the front edge of the gilding leaf on the top of the stack and transferring the leaf onto the active branch of said conveyor belt, at a relatively slow speed, and thanks to an intermitting suction effect. The transfer speed and the frequency of alternating movement of the mechanical hand are suitable for positioning the sequence of leafs which have just been staked on the conveyor belt.

[0007] In the cases in which a single reservoir and a single hand are used, the hand preferably transfers in the direction of movement of the active branch of the suction conveyor belt.

[0008] At least two mechanical hands with respective leaf reservoirs can be used to increase the production rate while limiting the transfer speed of the leafs from the reservoir to the conveyor belt. One first of said mechanical hands is suitable for arranging the sequence of leafs in distanced positions, with a gap which is essentially equal at least to the dimension of the leaf in the direction of advancement of the conveyor belt; at least one other mechanical hand is suitable for arranging the leafs in the gaps between the previously arranged leafs; the latter mechanical hand can make transfers which are orthogonal with respect to the movement of the conveyor belt.

[0009] Each leaf reservoir comprises a light presser acting on the stack of leafs, which is temporarily lifted to transfer the leaf on the top of the stack. Furthermore, each reservoir can comprise means for slowly lifting the reservoir containing the stack of leafs as said stack is used up.

[0010] Each mechanical hand will be advantageously equipped with means for adjusting the position of the suction tube so to ensure a limited gap with respect to the leaf to be picked up, thus avoiding direct contact with the stack of leafs.

[0011] The invention will now better understood, with reference to description and the accompanying drawing, which shows a practical non-limiting embodiment of the invention. In the drawing:

Figs. 1 and 2 show a lateral general view and a plan view according to II-II in Fig. 1, illustrating a general view of the system comprising the apparatus according to the invention,

Fig. 3 shows a detail of the zone indicated by the arrow III in Fig.1,

Fig. 4 shows a plan view according to the line IV-IV in Fig. 3,

Fig. 5 shows a blown-up detail of the zone indicated by arrow V in Fig. 1,

Fig. 6 is a plan view according to the line VI-VI in Fig. 5,

Fig. 7 shows a local cross-section according to VII-VII in Fig. 5 illustrating the leaf reservoir,

Fig. 8 is a cross-section on a much larger scale of a detail according to the line VIII-VIII in Fig. 3,

Fig. 9 shows a different embodiment with respect to Fig. 8, illustrating the operation on two strips instead of one,

Fig. 10 shows a blown-on local view according to X-X in Fig. 3,

Fig. 11 shows a blown-up detail indicated by arrow fXI in Fig. 3, and

Fig. 12 shows an outlined plan view of a different embodiment equivalent to that of Fig. 6.

[0012] A system of the known type for the application of gilding leafs on strips L is outlined in Figs. 1 and 2, as well as in Figs. 3 and 4. The system comprises a set of supporting and advancing rollers, indicated by reference numeral 1, on which the strips, such as L, are arranged. The strip, or strips, are advanced according to the arrow f to receive the so-called "imitation gold" leafs D which are extremely thin. Until now, these leafs were applied manually by very specialized operators, who would take the single leafs from containers, in the form of reservoirs of staked leafs, arrange them and make them adhere to the surface of the strip, or the strips, L, advancing according to the arrow f, on which glue was applied on the surface to be gilded and on which the coating, formed by extremely thin leafs of imitation gold, is distributed so that the leafs were thus glued onto the surface of the strips. Any overlapping between the various leafs applied in sequence to the strip was eliminated simply by rubbing. This operation would remove the film in excess of the overlapping leaf, thanks to the extreme fragility of the leafs. Any leaf in excess with respect to the zones where glue is applied on the surface to be gilded was eliminated manually, again by exploiting the extreme fragility and weakness of the imitation gold leafs which were used.

[0013] Reference numerals 3 and 4 indicate some of the lateral and vertical guide means for guiding the strips. These strips are fed to receive the gilding after applying a special specific glue, such as the so-called "mission" on the strips.

[0014] The manual operation of applying the leafs is costly and difficult, due to the high specialization of labor required for these manual operations.

[0015] The invention relates to an apparatus for mechanically and automatically applying gilding leafs without needing the particular intervention of specialized labor.

[0016] As illustrated in the accompanying drawing, the apparatus firstly comprises a continuous conveyor belt 12, which turns on free cylinders 14, 16, 18 and others; advancement is controlled by an encoder 14A, associated to the cylinder 14; the belt 12 is pervious to the air because its active section, specifically the upper part, must be aspirating to withhold the leafs (which are arranged on said conveyor belt after being transferred by feeding and depositing means) until they reach the strip, or strips, L, which are fed according to the arrow f under the free cylinder 18. In order to obtain this suction effect through the conveyor belt 12, which is pervious to air, a set of boxes, such as 20, 22, subject to vacuum via a suction conduit 24, is provided. The upper wall 20X, 22X in contact with the belt 12, which runs thereon according to the arrows f12, is in the form of a grill or perforated, for which the conveyor belt is aspirating along the path between the free cylinder 14, the free cylinder 16 and at least to the free cylinder 18. The latter is also perforated so to determine a suction effect also along the rotating surface of said free cylinder 18 (also see Fig. 11). Means, generally indicated by reference numerals 30 and 32 and described below, are provided to arrange a sequence of imitation gold leafs, indicated by reference letter D, which are arranged so that they slightly overlap one on the other as outlined by D1 in Fig. 11, however ensuring a continuity of surface of the gilding leafs on the conveyor belt 12, which advances in the direction of the arrow fA. The conveyor belt 12 continues beyond the free cylinder 18, which is pervious, distancing the free cylinder 18 until it reaches a pressure roller indicated by reference numeral 34. This roller 34 - which is replaceable - is contoured according to the profile of the fed strip, or strips, L and the edge is elastic so to press on the surface of the strip, or strips, L as shown in the drawing (see the different embodiment in Figs 8 and 9, specifically). The pervious conveyor belt 12 is consequently also transmitted by the pressure roller 34 and guided to reach the initial free cylinder 14 of the active section of the conveyor belt 12. The gilding leafs D are transferred, as shown above, until they are between the strip, or strips, L and the pressure roller 34, which presses the gilding leaf D against the surface of the strip, or strips, which must be gilded and on which "mission" glue (known in the prior art for this purpose) was applied. The glue is distributed on the surface to be gilded of the strips L immediately before the strips are fed onto the rollers 1 and, consequently, under the pressure roller 34, which thus compresses the leafs D which are progressively fed by the conveyor belt and makes them stick so to coat the strips conveyed according to the arrow f. As appears particularly in Figs 8 and 9, the strip L in Fig. 8, or the two strips in Fig. 9, are coated by the leafs D, which stick to the surface to be gilded. The excess D1 of the gilding leafs D which is not applied is easily eliminated manually or mechanically, i.e. by means of brushes, or other, which operate on the excess D1, either by destroying it, removing it, or recovering it, if required. The conveyor belt 12, which is deformed between the pressure roller 34 and the drive roller 1, is flattened as it is distanced from the pressure roller 34 to return, so flattened, to the free cylinder 14.

[0017] Advantageously, a second pressure roller 38 can be provided after the pressure roller 34. The second pressure roller is also contoured and provided with an elastic edge to complete the application of gilding leafs on the conveyed strips, to assist the operation previously carried out by the pressure roller 34.

[0018] The pressure roller 34 and the additional pressure roller 38, if provided, can be advantageously carried by a structure 40, which can be vertically adjustable, in relation to the morphology of the strips L, and particularly in relation to their thickness, so to adapt the distance between the drive rollers 1 and the pressure roller, or rollers, 34 - and 38 if provided - to the morphology of the strip, or strips, to be gilded. Also the guide rollers 4 and 3, if provided, can be adjusted to be adapted to the various types of strips to be gilded.

[0019] The strips L will reach the end of the system coated by the gilding D, as indicated by reference L1 in the Figs. 3 and 4.

[0020] Two walls 50, which can be flexible if required, are advantageously provided in the zone between the switch from the free cylinder 18 to the strips L and from the strips L to the pressure roller 34 to ensure maximum regularity of application of the gilding leafs D by the belt 12. The walls 50 are arranged along the conveyor belt 12 and the cylinder 18 and define a zone comprised between the two walls 50, the box 22, the cylinder 18 and the pressure roller 34, so to create a slight vacuum also in this zone between the two walls 50 and between the free cylinder 18, the box 22 and the pressure roller 34, so that the leafs D are securely held in contact with the section of the conveyor belt 12 between the free cylinder 18 and the roller 34 until they are arranged on the surface to be gilded of the strips L, as clearly appears in Fig. 11, and as indicated by the way of an example also in Fig. 8, in the top of which the belt 12 is isolated and shown as it advances to reach the contact with the strip L and the pressure roller 34, in cross-section and blown-up, with gilding leaf D in the zone underneath, with adhesion by suction effect through the cylinder 18 and the belt 12, between the two flexible walls 50 defining the restricted vacuum zone, which is exerted through the perforation in the free cylinder 18 which is in communication with the suction box 22.

[0021] The two units 30 and 32 are provided to feed the gilding leafs D onto the surface of the active section of the conveyor belt 12 between the free cylinders 14 and 16 to be withheld by suction through the pervious belt 12 and the perforated wall 22X of the box 22 in which the belt 12 runs.

[0022] The unit 30 consists of a reservoir of gilding leafs which are loaded in the form of a stack P (see Fig. 5), whereby forming a reservoir of leafs. The bottom 52 of the stack reservoir is susceptible of being very slowly moved upwards by means of a geared motor system 54 providing an extremely high reduction, to ensure that the level of the leaf on the top of the stack being used is essentially constant as the single leafs are taken. The stack P is very slightly pressed by an extremely light presser 56 (nearly as light as a duster), which is regularly lifted from the stack P being used up whenever a top leaf D is taken from the top of the stack; this duster 56 can be lifted or lowered by a timely fashion by an actuator 57 which is specially synchronized with the conveyor system 30 described herein.

[0023] The unit 32 is a mechanical hand for picking up the top leaf from the stack P being used - in the moment in which the light presser 56 is lifted - to transfer said leaf to the active upper section of the pervious conveyor belt 12, immediately after the free cylinder 14 of the belt. This mechanical hand (also see Fig. 7) comprises a slide 58 susceptible of moving on a supporting and guiding body 60 according to the direction of advancement of the conveyor belt 12. A suction tube 64, whose lower side presents a set of suction holes, which aspirates the top leaf on the stack P and picks up said leaf, is fitted on the slide. The body 60 can be raised and lowered by an actuator 65. The tube 64 is approached nearly to skim the leaf without compressing the remaining stack P and recalling it by effect of suction through the holes in the suction tube 64. After picking up the leaf D on the top of the stack, the suction tube 64 is raised by the body 60 and the slide 58 is moved in the direction of the arrow fA to slowly transfer the gilding leaf D taken by the suction tube 64. The gilding leaf D is lowered nearly onto the active section of the pervious conveyor belt 12, so to delicately arrange it and subject it to suction by vacuum by the suction box 20. The suction effect of the suction tube 64 is ceased at this point; the leaf D is abandoned and transferred by the conveyor belt 12. Aspiration by the suction tube 64 is resumed again when said tube 64 is taken back to nearly skim the next top leaf in the stack P being used up in the reservoir by the unit 30.

[0024] The operation of transferring the gilding leaf from the reservoir to the conveyor belt must be extremely delicate and, consequently, very slow. To ensure a higher production rate and considering the slowness of the transfer of the various gilding leafs D on the conveyor belt, in certain cases a dual feeding system of gilding leafs from two different reservoirs with respective mechanical hands, such as that described above, may be envisaged. A layout of this kind is illustrated in Fig. 12 where - in addition to the presence of the reservoir of the unit 30 - a second reservoir is provided in a second unit 130 containing a second stack P1 of gilding leafs D, which is located on a side of the initial active section of the conveyor belt 12, between the free cylinders 14 and 16. An additional mechanical hand unit, similar to the one designated 32 and described above, can be combined to the unit 130 to pick gilding leafs from the stack P1 and arrange them on the conveyor belt 12 in the gaps in correspondence to unit 130, such as that comprised between the two gilding leafs D3 and D4 which were distributed at a distance one from the other, as indicated with references in D3, D4, DX, since the transfer by unit 30 to the conveyor belt 12 is slower than the speed of the conveyor belt 12. In the case, a second set of gilding leafs will be transferred, as those in positions D5, D6, etc., from reservoir P1 in unit 130, in a direction with is orthogonal to the direction of advancement of the conveyor belt. The transfer will be suitably timed with respect to the lowering of the mechanical hand, which transfers the gilding leafs from the stack P1 to the conveyor belt, in the gaps comprised between the leafs D3 and D4 previously arranged on the conveyor belt.

[0025] These operations are practically all automated and, consequently, the presence of operators is exclusively dedicated to overlooking the various operations without the need for particular interventions.

[0026] It is noted that the drawing is provided by the way of an example only and that numerous changes can be implemented to the construction and embodiments of the invention herein envisaged without departing from the scope of the present invention. The presence of reference numerals in the annexed claims has the purpose of facilitating comprehension of the claims with reference to the description and the drawings and does not limit the scope of protection represented by the claims.

Claims

1. Apparatus for automatically feeding and applying thin "imitation gold" gilding leafs along a strip advancement path, in a machine for coating strips for frames or other with said leafs, said leafs being applied in sequence on the advancing strip, or strips, characterized in that it comprises: a pervious conveyor belt (12) with an active branch, said conveyor belt being subjected to vacuum - by means of pervious walls of suction boxes (20, 22) - along the active branch for transporting the leafs (D) to a free cylinder (18), after which the belt skims the surface of the strip, or strips, (L) on which glue has been applied, to apply the leaf thereon; at least one contoured, elastic pressure roller (34) to make the gilding leafs (D), fed in sequence by the conveyor belt (12), adhere to the strip or strips (L), said belt being entrained around said pressure roller (34); and means for continuously arranging a sequence of leafs on said conveyor belt.

2. Apparatus according to claim 1, characterized in that it comprises walls (50), which can be flexible, arranged along the conveyor belt (12) for gilding leafs (D) between the free cylinder (18) and the pressure roller (34), there being created a slight vacuum for accompanying the leafs (D) until they are arranged on the transiting leaf, or leafs, (L), between the walls (50).

3. Apparatus according to claim 2, characterized in that said free cylinder (18) of the pervious conveyor belt (12) is perforated to create said slight vacuum between the two walls (50).

4. Apparatus according to claim 1, characterized in that it comprises at least a second pressure roller (38) acting in sequence on the surface of the strip, or strips, already coated by the gilding leafs.

5. Apparatus according to claim. 1, characterized in that said means for arranging the sequence of gilding leafs (D) on the conveyor belt (12) comprise: a reservoir (30, 52) containing a stack (P) of said leafs; a mechanical hand (32) providing alternating movement and equipped with a transversal suction tube (34) with a set of holes for picking and lifting the front edge of the gilding leaf (D) on the top of the stack (P) and transferring the leaf onto said conveyor belt (12), at a relatively slow speed, and thanks to an intermitting suction effect.

6. Apparatus according to either claim 1 or claim 2, characterized in that the transfer speed and the frequency of alternating movement of the mechanical hand (32) are suitable for positioning the leafs slightly superposed one onto the other on the conveyor belt (12).

7. Apparatus according to claim 6, characterized in that the mechanical hand transfers in the direction of movement of the active branch of the suction conveyor belt.

8. Apparatus according to at least claims 1 and 5 or claims 1 and 6 or claims 1 and 7, characterized in that it comprises at least two reservoirs for leafs (30, 130), with respective mechanical hands, a first of which (32) being suitable for arranging the sequence of leafs (D3, D4) in distanced positions with a gap (X) which is essentially equal to the size of the leaf in the direction of advancement of the conveyor belt, and at least one other mechanical hand being suitable for arranging the leafs (D5, D6) in the gaps (X) between the previously arranged leafs.

9. Apparatus according to claim 5, characterized in that each reservoir of leafs comprises a light presser (55) acting on the stack (P) of leafs which is temporarily raised to transfer the leaf on the top of the stack.

10. Apparatus according at least to claim 5, characterized in that it comprises a means (54) for slowly raising the reservoir containing the stack of leafs progressively as the stack is used up.

11. Apparatus according at least to claim 5, characterized in that it comprises means for regulating the position of the suction tube (64) of the mechanical hand (32) so to ensure a limited gap with respect to the leaf to be picked up, whereby avoiding contact of the tube (64) on the stack of leafs.

12. Apparatus according at least to claims 1 and 4, characterized in that the pressure roller, or rollers, (34, 38) are adjustable and replaceable, according to the morphology of the strips to be gilded.

Drawing