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(11) | EP 2 990 171 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | METHOD AND DEVICE FOR LOCALISED THERMAL-MELTING |
| (57) Method for localised thermal-melting, particularly for thermo-activating the adhesive
face of the edging strips in automatic edging strip processing devices for the industrial
production of furniture, comprises positioning the heat radiation means (4) substantially
at one of the two focuses (F1) of an elliptical-shaped semi-cylindrical mirror (3)
and localisation substantially at the other focus (F2) of the sliding pitch (8) of
the edging strip (9) passing guided thereon and constrained to supply the edging device
(11) with continuous adhesive confluence of the edging strip (9) to the edge (12)
of panels (13) made of wood or wood surrogate.
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DETAILED DESCRIPTION
State of the art
[0001] The edging technique, i.e. the perimeter application - on the thicknesses of wooden or, more often, surrogate wooden panels - of strips made of coating material for the quality enhancement and/or only covering/decorative purposes, made of various materials, is known in the furnishing industry.
[0002] In the usual embodiments, these strips of coating material are made of synthetic material webs, continuously applied by automatic machines, the so-called edginmg machines, which unwind the strip from reels, cut it into suitable segments to suit the panel perimeter, apply bonding material thereon on a face or activate the bonding material already pre-existent and make it adhere on the perimeter with respect to the panel, precisely at the thickness of the relative edge, unless in case of subsequent filing.
[0003] In the most modem implementation, these strips of edging material are made of polymeric strip material, usually polypropylene, made of one component but obtained in two co-extruded layers differentiated by the melting point: the layer intended to be exposed to view in the finished product has a higher melting point, while the inner layer has a lower melting point, so as to be more suitable to be thermo welded, in solidification, to the edge of the panels without need for further resins and/or bonding agents.
[0004] The thermo activation of the meltable face of polymeric edging webs thus made requires considerable heat, which, according to the prior art, is attained through laser beams, spread on the inner face of the strip through vibrating mirrors, or through optical cylinders.
Description of the specific technical drawback
[0005] These known thermo activation systems of polymeric edging webs thus made reveal considerable drawbacks and limits in terms of high costs of purchase and management of the laser beam generators, as well as in terms of risks to the physical safety of the operators, also considering the well known risks that may arise from high power laser beams.
Objects of the invention
[0006] In such context, the main object of the present invention is that of providing an innovative system for the thermo-activation of the bonding face of the edging strips in the furnishing industry, especially the meltable face of the one-component polymeric strips coextruded in two layers with differentiated melting point, so as to be efficient and feasible in the functions as well as easily applicable to the existent ptoduction lines, without revealing drawbacks, contraindications or inconveniences in terms of costs and safety.
[0007] Another object of the present invention is to attain the preceding object through a polyvalent system in terms of the dimension of the strip, adjustable according to the dispensable heat, low in terms of consumption and energy dispersion, modular in terms of application alternatives, simple in terms of maintenance and interchangeability, which can also be adapted to pre-existing systems and not explicitly conceived or designed to receive it.
[0008] A further object of the present invention is to attain the preceding objects through a simple and efficient system, that is safe in the operation and relatively low costs considering the results practically obtained therewith.
Summary of the solution concept
[0009] These and other objects are attained through the method and device for localised thermo-melting, particularly for the thermo-activation of the adhesive face of the edging strips in the automatic edging machines for the industrial production of furniture, according to the present invention, comprising positioning of heat radiation means (4) substantially at one of the two focuses (F1) of an elliptical-shaped semi-cylindrical mirror (3) and localisation substantially at the other focus (F2) of the sliding pitch (8) of the edging strip (9) passing guided thereon and constrained to supply the edging device (11) with continuous adhesive confluence of the edging strip (9) to the edge (12) of panels (13) made of wood or wood surrogate, as claimed hereinafter.
Description of the attached drawings
[0010] Further characteristics and advantages of the method and device for localised thermo-melting according to the present invention, shall be more apparent from the following detailed description of a preferred but non-exclusive embodiment thereof, represented solely by way of non-limiting example in the attached drawings, wherein:
Figures 1 and 2 respectively show a perspective and a plan view of an embodiment of a device according to the present invention;
Figure 3 shows a perspective view of an alternative embodiment of a device according to the present invention;
Figures 4 and 5 show two perspective views from substantially opposite angles of an embodiment of a device according to the present invention as applied to an edging group of panels on straight edges as schematically illustrated;
Figures 6 and 7 respectively show a perspective view and a lateral view of an embodiment of a device according to the present invention as applied to an edging group of panels on shaped edges as schematically illustrated.
Static description of the invention
[0011] With reference to such figures, and in particular to figure 1, an embodiment of the device for localised thermo-melting according to the present invention, comprises a body for example metallic 2, substantially parallelepiped-shaped in the illustrated embodiment, within which there is obtained a cavity 3, describing an elliptical-shaped semi-cylinder with mirror surface, hereinafter also referred to as elliptical mirror 3, cut parallel to the generatrices for planar cutting on a face of the parallelepiped-shaped body 2, substantially adjacent in the axis of one of its two geometric focuses F2 (also see figure 2), thus obtaining said focus F2 slightly external with respect to the elliptical mirror 3 is indicated in its entirety with 1.
[0012] The surface of the elliptical mirror 3 is preferably obtained with polished coating, in turn covered by a material capable of guaranteeing maximum reflection with respect to thermal radiation, for example gold.
[0013] In the elliptical mirror 3, substantially at the axis at the other of its two geometric focuses F1 (also see figure 2), there is arranged a plug 4 for generating suitably supplied infrared rays, whose fixed emission active segment preferably extends over the entire height of the elliptical mirror 3; it is fixed to a basement bracket 5, to which there is also fixed the parallelepiped-shaped body 2, for example by means of two pins 6 preferably ceramic pins.
[0014] In the alternative illustrated in figure 3 there is shown a variable emiossion plug 4, whose active segment is defined by an elastic gripper element 4A carried by a mobile electrode 4B
[0015] The parallelepiped-shaped body 2 preferably has a plurality of external cooling fins 7 and thus it may be exposed to a forced air flow which, through channels (not illustrated), may also be driven to carry, in slight positive pressurisation, the internal compartment of the parallelepiped-shaped body 2, i.e. elliptical mirror 3; the cooling may also be of the liquid type, thus hereinafter for the alternative embodiments.
[0016] At the axis of the geometric focus F2 of the elliptical mirror 3, externally with respect thereto, there is arranged the sliding passage 8 of an edging strip 9, for example and preferably of the one-component polymeric type obtained in two co-extruded layers differentiated by the melting point, called pitch 8 preferably being defined on the other side by two retro flex edges 10.
[0017] The edging strip 9 is advanced and driven, like in the prior art, by batteries of driven and idle rollers 11, which, downstream of the device for localised thermo-melting 1 according to the present invention, lead it to converge and thus press it on the edges 12 of wood or wood surrogate panels 13 carried to transit in succession by a conveyor 14, for continuous joining therewith according to the prior art, for the functions to be specified hereinafter.
Dynamic description of the embodiment
[0018] Thus, having completed the static description of a preferred embodiment of the device for localised thermo-melting according to the present invention, following is a dynamic description of the same:
The edging strip 9 is preferably of the one-component polymeric type, usually polypropylene, obtained in two co-extruded layers differentiated by melting point: the layer intended to be exposed to view in the finished product has a higher melting point, while the inner layer has a lower melting point, so as to be more suitable to be thermo welded, in solidification, to the edge of the panels 13 without need for further resins and/or bonding agents.
[0019] Like in the edging machines of the prior art, the edging strip 9 should be unwound from a supply reel, not illustrated, and advanced on a path by rollers 11 of the known type.
[0020] According to the present invention, when the edging strip 9 reaches before the device for localised thermo-melting 1, its pitch 8 occurs substantially at the second focus F2 of the elliptical mirror 3, externally but immediately adjacent to the elliptical mirror 3.
[0021] In this position, the heat radiation emitted by the plug 4, or any other source of 360° infrared radiation suitably shaped for the purpose arranged on the axis of the first focus F1, impacts the meltable face of the strip 9 with direct radiation on an angle α determined by the interspace between the edges of the planar cutting on the open face of the parallelepiped-shaped body 2 (particularly see figures 1 and 2).
[0022] In addition, on the angle with vertices on the axis of the plug 4 with respect to angle α, all heat radiations are reflected by the elliptical mirror 3 on the axis of its second focus F2, i.e. on the meltable surface of the strip 9 passing therethrough 8, affecting the latter obtaining an angle β (particularly see figures 1 and 2) concentrated on the focal axis F2.
[0023] This combined direct and indirect flow of infrared rays transfers from the first focus F1, i.e. from the source of heat 4, to the second focus F2, i.e. to the surface of the strip 8, about 90% of the heat energy generated by said source 4, which, if of suitable power, easily obtains the thermo-melting of the meltable face of the edging strip 2, i.e. the activation of the bonding face, without any contacts or adverse effects whatsoever in terms of safety and energy costs which are absolutely acceptable, even in terms of reducing dispersion.
[0024] The edging strip 2 with internal surface thus may thus continue its movement, according to the prior art, to be driven adjacent to the edges 12 of the panels 13 and pressed thereon by the special rollers 11 to adhere - by interstitial penetration of the polymeric resin after the cooling and solidification of the molten face.
[0025] The heat absorbed by the metal body 2, where the elliptical mirror 3 is provided, may be dissipated through fins 7, possibly with the help with a source of airflow of the known type.
[0026] This flow may be advantageously channelled into the elliptical mirror 3 to maintain the relative environment with slight positive pressure, so as to evacuate the stagnation of possible fumes.
[0027] Also advantageously, the localised thermo-melting device may be provided with a hinging element and which can be diverged through operative positioning, possibly with the part of the rollers adjacent thereto, or removable from the seat thereof for easy cleaning interventions against sedimentation of fumes and replacement of the entire device and its components.
Alternative embodiments
[0028] It is obvious that in further alternative embodiments still falling within the solution concept underlying the embodiment illustrated above and claimed below, the device for localised thermo-melting according to the present invention may be alternatively implemented through equivalent technical and mechanical elements, by means of devices possibly complemented by further integrative solutions, still falling within the solution concept illustrated above and claimed below.
[0029] In particular:
the heat generator may alternatively be made of any type of known device, or unknown to the state of the art, suitable for the purpose;
the body in which the elliptical mirror is obtained may alternatively be made of other materials other than metal, for example ceramic material, as well as alternatively shaped in any manner suitable for the purpose and it may alternatively be cooled with a liquid through suitable interspaces, ducts and heat exchangers;
the elliptical mirror may be variously shaped with variation of the interfocal distance;
the axial segment of the fulcrums, and also the height of the elliptical mirror, may be of any size capable of housing the height of the edging strips to be applied; in order to save energy, the axial sources of heat radiation may be designed to be activated even only as regards their portions, as illustrated in the alternative embodiment of figure 3, when applying edging strips with low height.
Advantages of the invention
[0030] As observable from the detailed description of a preferred embodiment outlined above and from the variations outlined above, the method and device for localised thermo-melting according to the present invention offers advantages corresponding to the attainment of these and other preset objects: as a matter of fact it integrates a functional, modular, polyvalent and safe method and device (with reference to the safety standards of the machines of the industry) suitable for the thermo-activation of the bonding surfaces of the edging strips especially in the furniture industry, which can also be adapted to pre-existing and operating systems even not explicitly designed to receive them.
KEY TO THE REFERENCE NUMBERS
[0031]
- 1 )
- device for localised thermo-melting in its entirety
- 2 )
- parallelepiped-shaped metal body defining the elliptical mirror
- 3 )
- elliptical mirror
- 4 )
- plug
- 4A)
- elastic gripper element in figure 3
- 4B)
- a mobile electrode in figure 3
- 5 )
- basement bracket
- 6 )
- ceramic pins
- 7 )
- cooling fins
- 8 )
- sliding passage of the edging strip
- 9 )
- edging strip
- 10 )
- retroflex edges
- 11 )
- driving, return and pressure rollers
- 12 )
- sides of the panels
- 13 )
- panels
- 14 )
- panel conveyor
- F1 )
- first focus of the elliptical mirror
- F2 )
- second focus of the elliptical mirror
- α )
- direct radiation angle
- β )
- indirect radiation incidence angle
1. Method for localised thermal-melting, for thermo-activating the adhesive face of the
edging strips in automatic edging strip processing devices for the industrial production
of furniture, characterised in that it comprises positioning heat radiation generator means (4) substantially at one
of the two focuses (F1) of an elliptical-shaped semi-cylindrical mirror (3) and localisation
substantially at the other focus (F2) of the sliding pitch (8) of the edging strip
(9) passing guided thereon and constrained to supply the edging device (11) with continuous
adhesive confluence of the edging strip (9) to the edge (12) of panels (13) made of
wood or wood surrogate.
2. Device for localised thermal-melting, for thermo-activating the adhesive face of the
edging strips in automatic edging strip processing devices for the industrial production
of furniture, implementing the method of claim one, characterised in that it comprises heat radiation generator means (4) positioned substantially at one of
the two focuses (F1) of an elliptical-shaped semi-cylindrical mirror (3) and sliding
passage (8) of the edging strip (9) located substantially at the other focus (F2),
passing guided thereon and constrained to supply the edging device (11) with continuous
adhesive confluence of the edging strip (9) to the edge (12) of panels (13) made of
wood or wood surrogate.
3. Method according to claim one, characterised in that said edging strip (9) is of the one-component copolymer type comprising two co-extruded
layers differentiated by the melting point with a layer having a higher melting point
with exposed surface in the finished product and layer having a lower melting point
with inner meltable face suitable to be thermal-molten for solidification adhesion
to the edge of the panels (13) without the help of further resins and/or bonding agents.
4. Device according to claim two implementing the method of claim one and three, characterised in that said edging strip (9) is of the one-component copolymer type comprising two co-extruded
layers differentiated by the melting point with a layer having a higher melting point
with exposed surface in the finished product and layer having a lower melting point
with inner meltable face suitable to be thermal-molten for solidification adhesion
to the edge of the panels (13) without the help of further resins and/or bonding agents.
5. Device according to any one of claims two and four, characterised in that it comprises:
- a structure (2) defining a cavity (3) forming an elliptical-shaped semi-cylindrical element with mirror surface (3) cut parallel to the planar cutting generatrices of the constituting structure (2) substantially internally adjacent to the axis of one of its two geometric focuses (F2) thus leading to said focus (F2) outside the elliptical mirror (3);
- segment-shaped means (4) for generating heat radiation housed in said elliptical mirror (3) substantially at the axis of one of the two geometric focuses (F1) of said elliptical mirror (3) whose active segment extends over part or the entire height of the elliptical mirror (3);
- sliding pitch (8) of an edging strip (9) located substantially at the axis of the other geometric focus (F2) of said elliptical mirror (3) externally and orthogonally with respect to the latter.
6. Device according to claim five, characterised in that said segment-shaped means (4) for generating heat radiation housed in said elliptical
mirror (3) substantially at the axis of one of the two geometric focuses (F1) are
constituted by a glow plug (4) for generating infrared rays whose active segment preferably
extends over the entire height of the elliptical mirror (3).
7. Device according to any one of claims five and six , characterised in that said segment-shaped means (4) for generating heat radiation housed in said elliptical
mirror (3) substantially at the axis of one of the two geometric focuses (F1) are
constituted by any kind of 360° segment-shaped infrared rays source suitable for the
purpose located on the axis of said focus (F1).
8. Device according to any one of claims from five to seven, characterised in that said structure (2) defining a cavity (3) describing an elliptical-shaped semi-cylindrical
element with mirror surface (3) is constituted by a metal body (2) preferably parallelepiped-shaped
provided with external cooling fins (7).
9. Device according to any one of claims from five to eight, characterised in that said structure (2) defining a cavity (3) describing an elliptical-shaped semi-cylindrical
element with mirror surface (3) is constituted by a metal body (2) preferably parallelepiped-shaped
provided with interfaces for the circulation of the coolant fluid.
10. Device according to any one of claims from five to nine, characterised in that said structure (2) defining a cavity (3) describing an elliptical-shaped semi-cylindrical
element with mirror surface (3) is constituted by a metal body (2) preferably parallelepiped-shaped
provided with channelling means for conveying airflow adapted to bring the compartment
forming said elliptical mirror (3) to positive pressure levels.