CA1124629A - Process and apparatus for sheet overlaying fabrication - Google Patents
Process and apparatus for sheet overlaying fabricationInfo
- Publication number
- CA1124629A CA1124629A CA287,678A CA287678A CA1124629A CA 1124629 A CA1124629 A CA 1124629A CA 287678 A CA287678 A CA 287678A CA 1124629 A CA1124629 A CA 1124629A
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- CA
- Canada
- Prior art keywords
- adhesive
- workpiece
- sheet
- water
- conveyer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a process for sheet overlaying fabrication wllich comprises the steps of: spray coating a workpiece which is caused to travel automatically with a water-soluble adhesive containing an additive reducing the viscosity thereof; semidrying the adhesive thus applied onto the workpiece; and bonding a thermoplastic sheet onto the workpiece by placing the sheet on the adhesive thus semidried on the workpiece and heating and pressing the sheet against the workpiece. By reducing the viscosity of the water-soluble adhesive, it may be applied with a spray gun. The disadvantages of solvent based adhesives are thereby avoided.
The present invention provides a process for sheet overlaying fabrication wllich comprises the steps of: spray coating a workpiece which is caused to travel automatically with a water-soluble adhesive containing an additive reducing the viscosity thereof; semidrying the adhesive thus applied onto the workpiece; and bonding a thermoplastic sheet onto the workpiece by placing the sheet on the adhesive thus semidried on the workpiece and heating and pressing the sheet against the workpiece. By reducing the viscosity of the water-soluble adhesive, it may be applied with a spray gun. The disadvantages of solvent based adhesives are thereby avoided.
Description
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1 This invention relates generally -to pr~cesses and apparatuses for sheet overlaying fabri~tion and more particularly to a process which comprises automatically applying as a coating an adhesive onto a material to be fabricated such as board or panel materials, drying this adhesive coating to a state referred to by expressions such as "set to touch" or ; "semidry" (hereinafter referred to as semidry, the correspond-ing process being referred to as semidrying), and then bonding a sheet thereonto by heating, spreading, and applying pressure thereby to accomplish overlaying fabrication. The invention relates also to a fabricating apparatus capable of practicing this fabrication process.
In general, a board or panel material (hereinafter referred to collectively as "board" or "board material") such as, for example, those of the cabinets of television receivers are covered by overlaying with decorative sheets on which wood grain patterns and the like are printed in order to obtain a beautiful external finish. In this sheet overlaying fabrica-tion, a process step of applying as a coating layer on the board an adhesive for bonding a sheet onto the board is necessaryO In the coating step, it is necessary that the àdhesive be applied uniformly over the board surface, even onto the concavities and convexities of the surface, so that ~e sheet will adhere evenly to the board without peeling off therefrom.
For this adhesive, in general, there are solvent-type adhesives such as, for example, synthetic-rubber-base adhesives, and water-soluble adhesives such as, for example5 emulsion-type adhesives of vinyl acetate resin.
When a solvent-type adhesive is used, spray coating ~0 ,' I
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1 by means ~f a spray gun is possible. However, since the adhesive is of solvent type, it is almost impossible to remove by automatîcally washing off the adhesive which has been sprayed onto parts other than the board material which do not ~ require coating as, for example, a conveyer conveying the board material. When the adhesive is thus adhering to the conveyer and cannot be removed, it will contaminate the back face of new boards which are successively loaded onto the conveyerO
~ Furthermore, the unremovable adhesive gives rise to difficulty in the unloading of the boards from the conveyer. For these ; reasons, a solvent-type adhesive cannot be employed in an automatic, continuous adhesive coating apparatus for production o~ this character. Solvent-type adhesives, furthermore, have had the drawback of being undesirable for use for reasons of erosion of the sheets to be bonded because of volatile solvents and work environmental hygiene because of emission of harmful gases.
On the other hand, when a water-soluble adhesive is used, it is possible to remove the adhesive adhering to un-~0 necessary parts by washing with waterO However, a water-soluble adhesive, in general, has a high viscosity of the order of, for example, 8,000 to 50,000 centipoises (cps) and cannot be applied by means of a spray gun.
For ~his reason, it has been the practice heretofore ; to apply water-soluble adhesives manually by means of a brush.
By this method, however, the work efficiency is poor. Moreover, the adhesive cannot be applied uniformly, whereby there arise defects such as sheets with!adhering brush marks.
In another known method of applying a water-soluble adhesive, a glue spreader roll is rotated to apply the adhesive ~ _ 3 _ 1 ` as a coatingO In this method, automatic, continuous coating is possible, but it is limited to the coating of objects of flat plate form, it being impossible to apply -the adhesive uniformly on board materials having a curved or bent surface or a shape having concavities and convexities. For this reason, it has been unavoidably necessary to resort to the above mentioned manual coating proqedure for applying water-soluble adhesives as coating on board materials having complicated curved or bent surfaces and concave and convex features.
Still another difficulty accompanying the water-soluble adhesives is that, when they are used to bond a sheet and thereafter dried, the drying step requires a long time in the case of natural drying and, in the case of forced drying by using a hot press or a hot air stream, there arises the risk of damaging and deforming the sheet and the board material because of the heat. In another known semidry method, the adhesive applied onto the board material is dried to a semidry state. For drying in this case, a hot air stream or an ~ infrared lamp has been used, and for this reason, a long drying .~0 time has been required. When an attempt is made to shorten this time, the temperature within the drying oven must unavoidably be raised, thereby giving rise to the risk of thermal deforma-~ tion of the board.
`; A further problem encountered heretofore has been ` the difficulty of automatically carrying out the work of bond-ing a decorative sheet uniformly onto a board material having a curved surface shape and concavi-ties and convexities. The uniform bonding particularly of a very thin thermoplastic sheet without producing wrinkles has been very difficult.
Accordingly, it is a general object of -the present .
1 This invention relates generally -to pr~cesses and apparatuses for sheet overlaying fabri~tion and more particularly to a process which comprises automatically applying as a coating an adhesive onto a material to be fabricated such as board or panel materials, drying this adhesive coating to a state referred to by expressions such as "set to touch" or ; "semidry" (hereinafter referred to as semidry, the correspond-ing process being referred to as semidrying), and then bonding a sheet thereonto by heating, spreading, and applying pressure thereby to accomplish overlaying fabrication. The invention relates also to a fabricating apparatus capable of practicing this fabrication process.
In general, a board or panel material (hereinafter referred to collectively as "board" or "board material") such as, for example, those of the cabinets of television receivers are covered by overlaying with decorative sheets on which wood grain patterns and the like are printed in order to obtain a beautiful external finish. In this sheet overlaying fabrica-tion, a process step of applying as a coating layer on the board an adhesive for bonding a sheet onto the board is necessaryO In the coating step, it is necessary that the àdhesive be applied uniformly over the board surface, even onto the concavities and convexities of the surface, so that ~e sheet will adhere evenly to the board without peeling off therefrom.
For this adhesive, in general, there are solvent-type adhesives such as, for example, synthetic-rubber-base adhesives, and water-soluble adhesives such as, for example5 emulsion-type adhesives of vinyl acetate resin.
When a solvent-type adhesive is used, spray coating ~0 ,' I
I
l~ Z~Z~
1 by means ~f a spray gun is possible. However, since the adhesive is of solvent type, it is almost impossible to remove by automatîcally washing off the adhesive which has been sprayed onto parts other than the board material which do not ~ require coating as, for example, a conveyer conveying the board material. When the adhesive is thus adhering to the conveyer and cannot be removed, it will contaminate the back face of new boards which are successively loaded onto the conveyerO
~ Furthermore, the unremovable adhesive gives rise to difficulty in the unloading of the boards from the conveyer. For these ; reasons, a solvent-type adhesive cannot be employed in an automatic, continuous adhesive coating apparatus for production o~ this character. Solvent-type adhesives, furthermore, have had the drawback of being undesirable for use for reasons of erosion of the sheets to be bonded because of volatile solvents and work environmental hygiene because of emission of harmful gases.
On the other hand, when a water-soluble adhesive is used, it is possible to remove the adhesive adhering to un-~0 necessary parts by washing with waterO However, a water-soluble adhesive, in general, has a high viscosity of the order of, for example, 8,000 to 50,000 centipoises (cps) and cannot be applied by means of a spray gun.
For ~his reason, it has been the practice heretofore ; to apply water-soluble adhesives manually by means of a brush.
By this method, however, the work efficiency is poor. Moreover, the adhesive cannot be applied uniformly, whereby there arise defects such as sheets with!adhering brush marks.
In another known method of applying a water-soluble adhesive, a glue spreader roll is rotated to apply the adhesive ~ _ 3 _ 1 ` as a coatingO In this method, automatic, continuous coating is possible, but it is limited to the coating of objects of flat plate form, it being impossible to apply -the adhesive uniformly on board materials having a curved or bent surface or a shape having concavities and convexities. For this reason, it has been unavoidably necessary to resort to the above mentioned manual coating proqedure for applying water-soluble adhesives as coating on board materials having complicated curved or bent surfaces and concave and convex features.
Still another difficulty accompanying the water-soluble adhesives is that, when they are used to bond a sheet and thereafter dried, the drying step requires a long time in the case of natural drying and, in the case of forced drying by using a hot press or a hot air stream, there arises the risk of damaging and deforming the sheet and the board material because of the heat. In another known semidry method, the adhesive applied onto the board material is dried to a semidry state. For drying in this case, a hot air stream or an ~ infrared lamp has been used, and for this reason, a long drying .~0 time has been required. When an attempt is made to shorten this time, the temperature within the drying oven must unavoidably be raised, thereby giving rise to the risk of thermal deforma-~ tion of the board.
`; A further problem encountered heretofore has been ` the difficulty of automatically carrying out the work of bond-ing a decorative sheet uniformly onto a board material having a curved surface shape and concavi-ties and convexities. The uniform bonding particularly of a very thin thermoplastic sheet without producing wrinkles has been very difficult.
Accordingly, it is a general object of -the present .
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invention to provide a novel and useful sheet overlaying fabrication process in which the above described difficulties have been overcome and an apparatus for practicing this process.
Another and specific object of the invention is to provide a process and apparatus for sheet overlaying fabrication in which a water-soluble adhesive ~s spray coated onto an article to be fabricated, and a sheet is bonded to the article by the adhesive thus coated. According to thè present invention, n a~r~é s-~cf~
~ ~a diluent and a surfactant are added to the water-soluble l adhesive, and the viscosity thereof is lowered, whereby automatic, continuous spray coating by means of a spray gun is possible.
Since the process is spray coating, uni~orm adhesive coating can be carried out even when the article being fabricated ~ has curved or bent surfaces, concavities and convexities, and the like. Furthermore, since the adhesive is water soluble, any adheslve adhering to the conveyer and the like can be readily removed by washing with water.
Still another object of the invention is to provide a process and apparatus for sheet overlaying fabrication in ~0 which the adhesive coated as described above is semidried in a relatively short time and, moreover, without causing thermal deformation of the article being fabricated.
A further object of the invention is to provide a process and apparatus for sheet overlaying fabrication in which, irrespective of the surface shape of the article to be fabricated, a thin thermoplastic sheet is bonded onto the surface of the article uniformly coated with an adhesive without producing shrinkage 7 wrinkles, and the like.
` Further objects and features of the invention will be apparent from the following detailed description when ,.
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1 read in conjunction with the accompanying drawings, in which FIG.l is a plan view showing the general arrangement of one embodiment of an apparatus for carrying out a process step of spray COatillg an adhesive of one embodiment of the sheet overlaying fabrication process according to the invention and for carrying out semidrying of the adhesive thus coated;
FIG.2 is a side elevation orthogonal to FIG~l of the . same apparatus;
I FIGo3 is a partial perspective view of a part of the apparatus shown in FIGS~l and 2 at which a spray gun reverses its reciprocating motion;
FIG~4 is a partial perspective view of a part of the apparatus shown in FIGSol a~d 2 in which excess adhesive ~ flows off;
FIG~5 is a partial perspective view of a part of the apparatus shown in FIGS.l and 2 in which a conveyer bar washing device is provided;
FIG~6 is a perspective view of one example of a workpiece;
~0 FIGo7 is an elevation, with parts in vertical section, of one embodiment of a device for carrying out the step of bonding a sheet onto a workpiece coated with the adhesive of the embodiment of the sheet overlaying fabrication process according to the invention;
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FIGSo 8A through 8I are elevations, in vertical section~ respectively showing the operational states in operation sequence of the device illustrated in FIG~7;
FIG~ 9A and 9B are perspective views respectively . showing examples of spacers suitable for use in the device shown in FIGo7;
~ - 6 -1 FIG.10 is a perspective view of a pallet and its loading platform part of the device shown in FIG.7; and FIG.ll is a diagram for a description of the deform-ing actions of springs in a shock absorbing mechanism of the device illustrated in FIG~7.
An automatic adhesive applying device of one embodiment of a fabrication apparatus for carrying out the sheet overlaying fabrication process of the present invention will first be described with reference to FIGS.l through 5.
This automatic adhesive applying device 10 comprises a process section Pl for automatically applying an adhesive and washing of excess adhesive and a process section P2 for ; semidrying the adhesive. These process sections Pl and P2 are provided with first and second conveyers 12 and 13, respectively, which are contiguously disposed and driven by I a motor 14.
As will be apparent from FIGS.3, 4, and 5, the conveyer 12 is disposed between a pair of support rollers 16a and 16b.
The conveyer has a plurality of transverse conveyer bars 15 o supported at their ends in rotatable state at equal spacing intervals.
I As shown in FIG.4, each workpiece 17 is loaded with its surface to be processed on the upper side onto the conveyer 12 from the supply side ~ and is conveyed in the .~5 ~ arrow direction A. The workpiece 17 may be an aricle of complicat ed shape having, for example, a planar part 17a, a recessed park 17b9 side face parts 17c, and curved parts 17d, as shown in FIG.6. The material of the workpiece 17 is not limited `l to wood and wood products but may be any of other materials such as synthetic resins and metals. The workpiece 17 thus .j conveyed is spray coated with an adhesive by a spray gun 18 as described hereinafter.
Referring to FIGS. l and 2, compressed air at a primary air pressure of the order to 5 kg./cm2., which has been supplied from a source such as an air compressor (not shown) through an air hose 19, is passed throuyh an air filter 20 and a mist separa-tor 21, thereby being cleaned, and then, after being pressure regulated by a primary pressure reducing valve 22, is distributed and supplied to a pressure tank 23 and the air spray gun 18.
Within the pressure tank 23 is stored a water-soluble adhesive of a synthetic resin (e.g., vinyl acetate resin) emulsion type in a suitably agitated state, being pressurized under a pressure of approximately 0.5 to 1.5 kg./cm . and, moreover, being continually agitated. In general, a water-soluble adhesive has a high viscos-ity above lO,OOOcps. and cannot be used for spray coating. In the present invention, however, the viscosity is adjusted to a value of the order of 1,000 to 5,000 cps. at which spray coating is possible by lowerin~ it to a degree which will not impair the adhesive strength by adding a diluent, a surfactant, and the like ~0 to the adhesive. An aqueous solution of an acrylic substance having a low molecular weight wherein the viscosity of the aqueous solution is equal to or less than about 200 to 500 cps., for e~ample, is suitable for the diluent. A silicone surfac-tant is added to the adhesive thereby to prevent aggregation of the adhe-sive resin component on the surface of the wor]spiece to form particles after application of the adhesive and to reduce the sur-face tension of the adhesive surface to a value of the order of 20 to 40 dyne/cm. in order to improve the "wetting" pheno~enon.
A spreader is also added to the adhesive for the purpose of pre-venting "spattering" of the adhesive on the surface of the work-piece. The diluted water-soluble adhesive is ejected as a mist through the spray gun 18 by the pressure within thepressure tank 23 1 and the air spray pressure of the compressed air reaching the spray gun 18.
The spray gun 18 undergoes a traversing reciprocation ' in the transverse direction perpendicular to the traveling direction of the ~onveyer 12, being driven by a motor 25 through a crank 26 and guided by a guide 24 supported to extend transversely across and above the conveyer 12. Through the spray gun 18 thus undergoing this traversing reciprocating movement, the adhesive is ejected as a mist and is automatically spray coated on the upper face of each workpiece 17 being conveyed by the conveyer 12 and passing by the spray coating station as shown in FIG~4. Since the adhesi~e is applied by spray coating in this case, even when the workpiece 17 has a complicated shape, the adhesive is uniformly applied into all corners without skipped spots.
The speed of traversing reciprocation of the spray gun 18 is determined by setting the rotational speed of the motor 25 to an appropriate value in conformance with the traveling speed of the conveyer 12 so that the adhesive will '?0 be evenly applied. Furthermore, the traveling stroke of the spray gun 18 is set at a suitable value in relation to the width W of the workpiece 17 so that the spray gun will not reverse its traversing direction above the workpiece and -thus apply a double coating.
,~5 Any adhesive in mist form which has spread out and away from the workpieces 17 as a result of the spraying action of the spray gun 18 is discharged outside of the apparatus by `I a dust collector 27 provided with an exhaust fan (not shown).
Drainage devices 30a and 30b are disposed above the conveyer 12 and in the vicinities of the lateral edges thereof . _ 9 _ ,1 at respective positions in symmetrical opposition where the spray gun 18 reverses its traverse direction as indicated by the broken-line arrowO These drainage devices 30a and 30b are adjustably secured to a structural part of the apparatus by bolts 31 passed through slots 32 in parts of these drainage devices. Thus, the distance between these drainage devices can be adjusted to conform to the traversing stroke of the spray gun 18. The construction and disposition of the drainage device 30a is shown in FIG.3~ Since the drainage device 30b is of similar construction, its description will be omitted. The drainage device 30a has a draining inner surface 33 disposed with an inclination at the point of reversal of traversing move-ment of the spray gun 18 and a plate 34 for preventing scattering of adhesive. The height and the angle of inclination of the plate 34 are appropriately adjusted by means of wing nuts 35 in accordance with the degree of spattering of the adhesive due to the spray pressure, the ejection flow rate, and other factors.
The drainage device 3~a is supported at its one end by a bracket 36 and is provided with a water supply hose 37 for supplying a continuous supply of water, which is caused by the inclination ; of the draining inner surface 33 to flow therealong in the slight arrow direction.
The adhesive, which is being ejected from the spray gun 18 also when the spray gun reverses its traversing direction, is spxayed directly into the draining inner surface 33 and, at the same time, is sprayed onto the surface of the scattering prevention plate 34 to assume the form of drops which reach the draining inner surfaceO The excess adhesive which has thus reached the draining inner surface 33 is dissolved by the water supplied through the water supply hose 37 and is drained off via l i 1 ~ a drainage 38 and a drain pipe 3~ to the outside. The portions of the adhesive or the water which have spattered from the ; draining inner surface 33 at the time of the above described spraying of the adhesive are received by the scattering prevention plate 34 and thereby prevented from splashing onto the conveyer 12 and the workpieces 17. In this connection, the above mentioned spattering can be suppressed even more effectively by lining the draining inner surface 33 with a cushioning material such an urethane resin foam.
Thus, the adhesive ejected from the spray gun at the time of its reversal of traversing direction is effectively prevented from adhering directly to the conveyer 12.
In addition, as shown in FIG.4, a drainage pan 40 is installed between the upper and lower spans of the conveyer 12 at a position below-the spray gun 18. The interior of this drainage pan 40 is continually supplied with water from a water supplying hose ~1. Oversprayed adhesive is dissolved in the water flowing in the arrow direction in the drainage pan 40 and is discharged through a drain pipe 42 to the outside. Thus, adhesive which has been overspxayed to parts other than the workpieces 17 is prevented from adhering to the lower span of the conveyer 12 which is the return path thereof a~d, moreover, is discharged out of the apparatus.
A water vessel 45 is installed below the lower span of the conveyer 12 forming the return path thereof and is divided ~ into three separate vessels 46, 47, and 48 successively :` I
disposed in the travel direction of the lower span of the conveyer 12. These vessels 46, 47, and 48 are respectively provided with water supply hoses 52, 53, and 54 having at intermediate parts thereof water supply valves 49, 50, and 51 . ~
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1 and with water drain pipes 55, 56, and 57, whereby water is being contin~ally supplied into and drained from the interior of each vessel. That is, water is being continuously circulated ~. through all three vessels 46, 47, and 48.
The vessel 46 is provided thereabove with a fabric mop 58. This mop 58, which is continually sup~lied with water through the water supply hose 52, always contains an ample quantity of water, and excess water is dripping from its lower partO The vessel 47 is provided therewithin with a block of urethane resin foam 59 projecting upward to a height level where it contacts the conveyer bars 15 in the lower span of the conveyer 12 and containing an ample quantity of water. Further-more, the vessel 48 is provided similarly therewithin with a block of urethane resin foam 60. The water supply hose 54, which has a large number of flne perforations 61 formed therein, is laid over the upper surface of this urethane resin foam 60.
The conveyer bars 15 in the lower span of the conveyer 12 first contact the mop 58 as they travel past the vessel 46, and any adhesive adhering to the conveyer bars 15 is thus ~ dissolved and washed away. Next~ the conveyer bars 15 contact the upper surface of the urethane foam block 59 and rotate about their axes as they travel past the vessel 47, and any adhesive still adhering in dissolved state on the conveyer ~ars 15 is wiped off The conveyer bars 15 further contact the urethane foam block 60 and rotate as they travel past the last vessel 48, being subjected to a finishing water wash with water ejected from the fine perforations 61 of the water supply hose 54, and . any remaining adhesive still adhering to the conveyer bars 15 is completely removed. Finally, the conveyer bars 15 are wiped by a suspended sheet of dry cloth 62,whereupon the clea~ing ~ - 12 -., I
1 step is completed.
In this manner, all conveyer bars 15 o~ the conveyer 12 which have passed through the conveyer lower span are ' completely rid of ~he adhesive. Therefore, when the workpieces 17 are successively loaded onto the conveyer at the posi~ion X~
undesirable occurrences such as adhering of adhesive to the reverse side of the workpieces 17 to contaminate the same and sticking of the workpieces 17 to the conveyer bars 15 are prevented.
~ The workpieces which have been coated with adhesive in the above described manner are conveyed to the drying section of the apparatus, where the adhesive is semidried as described belowO Referring again to FIGS.l, 2, and 4, each workpiece 70 thus coated on its upper and side surfaces with the adhesive is automatically transferred at the downstream end of the conveyer 12 onto the conveyer 13, by which the workpiece 70 is thereafter convey~d in a similar manner in the arrow A direction~
Each coated workpiece 70 is thus conveyed first through a setting oven 71 and then through a lateral face drying oven 73 in which ~o far-infrared-ra~ heaters 72a and 72b are installed on respective opposite sides of the travel path of the workpieces 70. In this lateral face drying oven 73, the adhesive film applied on the lateral faces of each workpiece 71 is semidried. The workpiece 70 is then conveyed through an upper face drying oven 75 provided at the ceiling part thereof with far-infrared-ray heaters 74a through 74d, where the adhesive`film on the upper ~i face of the workpiece 70 is semidriedO Thus, the coating film on the late~al surfaces and the upper surface of each workpiece ~ 70 is semidriedO Finally each workpiece 70 is passed through and cooled by a cooling chamber 76 and is then conveyed to the ,1 " ~
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I succeedin~ sheet overlaying process section.
The above mentioned far-infrared-ray heaters 72a, 7~b, and 74a through 74d emit far-infrared ra~s which are in the invisible light ray region. The molecules and atoms of the adhesive coating film undergo torsional vibration and stretching vibration as a result of irradiation by the far-inf-rared rays.
; As a result of the exothermic hardening energy thus generated, heating and drying take place instantaneously in a ve~y short time even to deep layer parts, and uniform semidrying is achieved over the entire coated surface and throughout the entire film thickness.
Accordingly, by using these far-infrared-ray heaters, the adhesive of low viscosity in its coated stated is promptly dried before it can flow into the concavities and the side of `low sloped surface of each workpiece 70, and the coated adhesive film is semidried in a condition wherein it is main-tained at a uniform thickness. Furthermore, since the drying time is short, and the temperature rise during this drying step is not very great, there is no risk whatsoever of warp-~0 ing of the workpiece 70 itself or deterioration of the its material~
The setting oven 71 and the cooling chamber 76 are respectively disposed in front of and after the drying ovens 73 and 75 and function to prevent heat emission from these dry-ing ovens. Thus, the adhesive coating film is efficiently dried with a small quantity of heat. Furthermore, the inher surfaces of the ovens 71, 73, and 75 and the cooling chamber 76 are lined with a material such as steel plates with mirror surface finish so as to minimize heat loss. In the middle of this ~ group of contiguously alined ovens and cooling chamber, an , exhaust duct 77 is provided to discharge vaporized substances I I
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1 ~ within the ovens out of the apparatus.
The temperatures of the far-infrared-ray heaters 72a and 74b are detected by heat detecting devices 78a and 78b re~spectively attached thereto and connected to a temperature regulator mounted on a control panel 79, the temperature regulator thus operating to control the temperatures within the drying ovens 73 and 75. The temperatures of ~he far-infrared-ray heaters 72a and 72b and 74a through 74d may be controlled ` separately.
Each workpiece 70 coated with the adhesive and semi-dried as described above is conveyed off the conveyer 13 and then, as shown in FIG.8A, is fixed to a pallet 101 over a jig 102. Over this, a thin decorative sheet 103 made of a thermo-plastic resin is placed in a covering manner, and this assembly is conveyed by a pallet conveying device 104 into a sheet bonding device 100.
This sheet bonding device 100 comprises essentially a base 105, a lower vessel 106 fixed to the base 105, an inverted upper vessel 107 which is movable up and down, the upper and lower vessels 107 and 106 being disposed in opposed positions with their concavities facing each other, and a holding frame 108 disposed between the upper and lower vessels 107 and 106 and adapted to be movable in the up and down direction, as shown in FIG.7. Across the holding frame 108 is stretched a rubber sheet 109 of a thickness of the order of 1 mm. made of natural rubber base material which has been so treated that it has flexibility, heat resistance, and stretchability.
The holding frame 108 is pressed in contact against the lower vessel 106 over packings llla and lllb interposed therebetween by the elastic force of springs llOo The upper , ~ .
,1 ~J2 ~
1 ~ vessel 107 is pressed in contact with the holding frame 108 over packings lllc and llld interposed therebetween by the elastic force o~ springs 112. Thus, a sealed space 113 is ~ormed between the rubber sheet 109 and the upper vessel 107, and a sealed space 114 is formed between the rubber sheet 109 and the lower vessel 106.
A heater 115 comprising essentially a thin plate o~
silicon rubber and electric heating elements of metal foil embedded in the silicon rubber plate is installed at the ceiling of the upper vessel 107 and operates to generate heat uniformly over its entire surface. On one hand, as shown in FIGSo 8 and 10, stops 116 for pallet positioning, which are adapted to be moved up and down by means such as an air cylinder, and a ~ pair of carriers 117a and 117b for raising and lowering pallets are installed within the lower vessel 106.
An air pipe line 118 is connected to the upper vessel 107 and communicates with the space 113 therewithin. This pipe line 118 is provided at an intermediate part thereof with an electromagnetic changeover valve 119, which can be operated 'o to communicate the pipe line 118 to one end of either of two branch pipe lines 120a and 120b. The pi~e line 120a is connected at its o~her end to an air ~ompressor 121, while the pipe line 120b is connected at its other end to a vaccum tank 123 connected to a vacuum pump 122. Similarly, a pipe line 124 ?5 is connected to the lower vessel 106 to communicate with thespace 114 therewithin. The pipe line 124 is connected also to an electromagnetic changeover valve 125 by which it can be interchangeably commlmicated to one end of either of two branch lines 126a and 126b respectively connected at their other ends to the compressor 121 and the vacuum tank 123.
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Il - 16 -Next, the sheet bonding operation of the above described sheet bonding device 100 will be described with re~erence to FIGS ~ 8A through 8I
I To start the device 100, a motor (not shown) is started, whereupon a chain 127 for raising and lowering is driven by the motor through a speed reducing mechanism (not shown) comprising a worm and worm g~ar and raises the upper vessel 107, which is guided in vertical movement by guide posts 128 at four corners thereof, to a height position Hl as shown in FIG~ 8A.
lQ The above mentioned motor continues to operate to drive a chain ; 129 for raising and lowering via another speed reducing mechanism~ The chain 129 thus raises the holding frame 108, which is guided by guide posts 130 in the upward direction Yl.
Interrelatedly with the rising movement of the holding i5 frame 108, the carriers 117a and 117b within the lower vessel 106 are raised by the operation of an air cylinder 131 as shown in FIGo 10 ~ whereby the pallet conveying device 104 for convey-ing in and a pallet conveying device 132 for co-nveying out are held at the same height position. Also interrelatedly with the rising movement of the holding frame 108, the stops 116 similarly rise to their operational position.
When the holding frame 108 risès to its highest rise ; position, it presses against the lower surface of the upper ; vessel 107, which has already risen as shown in FIG.8B, and the air-tight, sealed space 113 is formed. Simultaneously, ` the vacuum pump 122 starts, whereby the air within the sealed i space 113, passing through the large number of through holes in the heater 115, is evacuated through the pipe lines 118 and 120b. As a result, the rub~er sheet 109 is drawn into intimate contact with the lower surface of the heater 115 as shown in , .
;' - 17 -,"
.: .
1 FIGo 8C and is uniformly heated by the heater 1150 It is to be noted that the rubber sheet 109 is drawn against the heater 115 along a spacer 134 of triangular cross section as shown in FIG.9A without developing any locally stretched parts, whereby deterioration of the rubber sheet material due to local stretching does not occur.
At this time, the pallet 101 is conveyed ~ogether with the workpiece 70 by the conveying device 104 and, passi~g over stationary carriers 135 on the lateral sides of the bond-ing device, is conveyed into the lower vessel 106. The pallet 101 is arrested by the stops 116 and is positioned at a specific position on the raising and lowering carriers 117a and 117b.
As shown in FIG.10, the pallet 101 carrying and holding the workpiece 70 is guided by tapered entrance grooves 137a and 137b formed at the leading part thereof and fits onto the pair of carriers 117a and 117b. Guide grooves 136a and 136b formed contiguously with the entranGe grooves 137a and 137b in the pallet 101 are thus guided, whereby lateral movement of the pallet in the transverse direction perpendicular to the direction of travel is limited, and the pallet is thus smoothly conveyed on a plurality of rollers 138a and 138b provided on the carriers. Furthermore, a large number of through holes 139 are formed in the pallet 101. At the bottom part of the lower vessel 106, there is provided a lattice-like support frame 140 comprising an assembly of transverse spanning members in grating formO
When it is confirmed that the pallet 101 sent into j the lower vessel 106 has stopped at a specific position, the upper vessel 107 and the holding frame 108, which are iIl a unitary state in ~ their raised positions as indicated in FIG.8~, i , .~ , , , ;; . , descend as they are in the arrow direction Y2. Similarly, the ascending and descending carriers 117a ~nd 117b supporting and holding the pallet lOl together with the workpiece 70 and the I stops 116 descend, and the pallet 101 is pla~ed on the lattice-like support fr~ne 140. At this time, the rubber sheet 109 is still drawn against and adhering to the heater 115 and is heated thereby.
The upper vessel 107 and the holding frame 198 ~I descend in the unitary state until, as shown in FIG.8E, the l lower surface of the holding frame 108 is pressed against the upper surface of the peripheral lip of the lower vessel 106, and the sealed space 11~ is ~ormed by and between the lower vessel 106 and the rubber sheet 109 adhering to the inner wall surfàce of the upper vessel 107. Simultaneously with the ` formation of this sealed space 114, the air within the space 114 is evacuated through the pipe lines 124 and 126b, whereby this sealed space 114 is subjected to reduced pressure and placed in a substantially vacuum state. At this time, suction ; through the pipe line 118 is still being continuedO~
When the interior of the sealed space 114 thus assumes a substantially evacuated state, and the space be-tween `~ the uneven part with concavities and convexities of the work~
piece 70 and the decorative sheet 103 assumes an amply evacuated state, the first electromagnetic changeover valve 119 is changed .~5 1 over, and the pipe line 118 is communicated with the pipe line 120a. As a consequence, high-pressure air from the compressor 121 is supplied through the pipe line 118 to enter forcibly between the inner wall surface of the upper vessel 107 and the Il rubber sheet 109, whereby the rubber sheet, which has been heated ` by the heater 115, is subjected to this pressure and, separating ., .
,1 1 'I .
~2~
.` ~
., I
from the inner wall surface of the upper vessel 107, descends at a high speed. As a result, the rubber sheet 109 presses against the upper and side surfaces of the workpiece in intimate ~ conformance with the contour thereof, and the deco-rative sheet 103, being pressed by the rubber sheet 109, is caused to cover the adhesive covered surface of the workpiece 70 in intimate contact and conformance with this surface as shown in FIG.8F.
At this time, the sealed space 114 is still being held in a vacuum state through the pip~ line 124. In the above case, the s~ne result may be obtained by merely opening the pipe line 118 `
to the atmosphere.
Since the above described rubber sheet 109 still retains heat at this time, the decorative sheet 103 is heated ; uniformly by this heat and softened. As a consequence of this ~ softening effect operating together with the pxessing action of the rubber sheet 109, the decorative sheet 103 is easily deformed and, accurately conforming to the concavities and convexities in the contour of the workpiece 70, adheres closely to the workpiece at every nook of its contour. Furthermore, 'n the heat from the rubber sheet 109 is transmitted through the overlaid sheet 103 to the adhesive, whereupon the adhesive in semidried stabe softens, and it adhesion is restored. The decorative sheet 103 is thereby caused to adhere closely to ` the surface of the workpiece 70.
i When the first sealed space 113 has been pressurized for a specific time required for carrying out the above described intimate adhering operation, only the upper vessel 107 is moved upwards in the arrow direction Y1 as shown in FIG.8G, and the ~ rubber sheet 109 is exposed. At this time, the evacuation through the pipe line 124 is still being continued, and the '! ' : ~, ` . .
.
1 ~ flexible rubber sheet 109 is pressing the decora-tive sheet 103 against the surface of the workpiece 70.
Then, with these operational parts in this state, a cooling and static electricity removing device 141 additionally provided in the bonding device is operated to cause the flow a stream of cool ionized air against the rubber sheet 109. By this action, the rubber sheet 109 and the decorative sheet 103 are cooled, and, at the same timeS the adhesive sets. Thus, the decorative sheet 103 is bonded to the workpiece surface.
l When the decorative sheet 103 is thus cooled, ittends to shrink, but its free shrinkage is restricted because it is being pressed against the workpiece 70 by the rubber sheet 1~9. Accordingly, the decorative sheet 103 is bonded in a uniformly stretched ~ state onto the surface of the workpiece 70 without the occur-rence of any shrinking or crimping as in the past- Furthermore, since the cool air in the above mentioned stream is ionized7 any static electricity generated between the rubber sheet 109 and the decorative sheet 103 is removed, and the rubber sheet 109 is easily separated froM the decorative sheet 103 :in the >o succeeding process step.
The cooling and static electricity removing device 141 comprises a hollow cylindrical structure 142 made of an electro-conductive material and having a large number of small holes formed therein in the longitudinal direction and a central conductor 143 disposed at the center of this cylindrical structure. With a high voltage applied between the central conductor 143 and the cylindrical structure 142, high~pressure air is supplied into the cylindrical structure 142, whereupon ionized cool air is blown out at a relatively high flow rate through the small holes as indicated by the arrow ma-rks.
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1 ~ After the above described cooling has been carried out for a specific time,the electromagnetic changeover valve 125 is changed over, and high-pressure air from the compressor 121 is supplied through the pipe line 124 as indicated by the arrow in FIG.8H into the sealed space 114. As a consequence, the rubber sheet 109, which is free oE attractive force due to static electricity, separates easily from the decorative sheet 103.
Then, as indicated in FIG.8I, the holding frarne 108 ~ moves upward. Simultaneously, the carriers 117a and 117b move upward, and the pallet 101 ascends to the height of the pallet conveying device 132. Thereafter, the pallet 101 bearing the sheet overlaid article 144 with the decorative sheet 103 bo~ded thereto passes over stationary carriers 145 and is conveyed out 15 ~ of the bonding device.
With the above described fabrication procedure, one cycle of the sheet overlaying process steps is completed. The operation is continued by repeating the above described process steps respectively with respect to the workpieces successively conveyed into the above described sections of the apparatus.
In the above described sheet bonding device 100, a spacer 146 as shown in FIGo 9B may be pro~ided arolmd the periphery of the lower vessel 106O By the use of this spacer 146, local , I
stretching of the rubber sheet 109 at the time it is forced into ` close contact with the workpiece 70 is effectively prevented, i similarly as in the case of the aforedescribed spacer 134 Next, the structural organization and operation of spring mechanisms provided for the upper vessel 107 and the holding frame`108 will be described, but since the mechanism li 1 respectively on the two sides are identical, only that on the ,. I
left-hand side as shown in FIG.7 will be described.
The aforementioned coil spring 112 is accommodated ' within a guide stand 152 of hollow cylindrical shape fitted around a vertical guide rod 151, which is loosely fitted in a hole in a flange part of the upper vessel 107, the guide stand 152 being ixed to the upper part of the flange part, The coil spring 112 is thus interposed between the flange part and a ring or collar 153 on the guide rod 151. The upper and lower ends of the guide rod 151 are connected to the aforementioned chain 127.
~ Relative to the holding frame lO~, the first coil I spring llO is accommodated within a guide stand 156 of hollow . cylindrical shape fitted around a guide rod 155, which is loosely fitted in a hole in a flange part of the holding frame 108, the guide stand 156 being fixed to the upper part of the flange part~ The coil spring 110 is thus interposed between -the flange part and a ring or collar 157 on the guide rod 155. A second ` coi.l spring 158 is disposed around the guide rod 155 below '10 the holding frame 108 and interposed between the flange part and a ring or collar 159. The upper and lower ends of the guide rod 155 are connected to the aforementioned chain 129.
At the time of the above described operation of the sheet bonding device lO0, the coil spring 122 ~mdergoes a variation in its length as represented by Lo~ Ll> L2 . The ,, first coil spring llO undergoes a variation in its length as I represe-nted by lo~ ll> 12 ? while the second coil spring 158 undergoes a variation in its length as represented by ,. l'o~ 1 l> 1 2-~ First, the state of the sheet bonding device 100 as .
, - 23 -Il , ., 1 shown in FIG.8~ wherein ~he upper vessel 107 has been raised with the collar 153 arrested by the guide stand 152, and the holding frame 108 has been raised with the collar 157 arrested by the guide stand 156 will be consldered. In this state of the device 100, the lengths of the coil springs 112, 110, and 158 are Lo, lo, andl'o, respectively, as indicated at stage in FIG~
The holding frame 108 r~ses further and strikes against the lower surface of the upper vessel 107 as shown in FIG.8B and stops, but the motor and the speed reducing mechanism operate further and then stop. At this time, the springs 112 and 158 are compressed, -thereby cushioning the load due to abrupt stopping which acts on the speed reducing mechanism. At this time, the lengths of these springs 112 and 158 respectively become Ll and 1'2 as indicated at stage ~ in FIG~ and this sta~e is su;stained until the state indicated in FIGo 8D is reached. At ~is time, moreover, the upper vessel 107 and the holding frame 108 are being pressed togè~her over a packing interposed therebetween by the resilient forces of these springs 112 and 158, whereby the space 113 is positively maintained in an air-tight state.
The upper vessel 107 and the holding frame 108 are lowe~ed unitarily and, striking the lower vessel 106 and assuming the states indicated in FIGS.8E and 8F, come to a stop, but the motor runs further and then stops. At this time the ` springs 112 and 110 are compressed, thereby cushioning the suddenly applied load due to stopping which is applied to the speed reducing mechanism. Furthermore~ as the springs 112 and 110 are compressed, the separate second spring 158 becomes effective, and the lengths of these springs 112, 110, and 158 '- 2~ -1 becomes L2, 12, and l'o, respectively, as indicated at stage 1.
~ in FIG.ll. The resilient forces of the springs 112 and 110 at this time press the upper vessel 107 and the holding frame 108 down~ard, and the spaces 113 and 114 are respectively maintained in air-tight state.
When the upper vessel 107 rises from the state indicat-ed in FIG.8F, the elastic force of the spring 112 acts in the direction for lightening the rotational load imposed on the ~ motor and the speed reducing mechanism at the time of start-~ ing thereof~ and, after the spring 112 has fully returned to its free state, the weight of the upper vessel 107 acts for ~ the first time on the speed reducing mechanism. In the state : wherein the upper vessel 107 has moved to its raised position indicated in FIGS.8G and 8H, the springs 112, 110, and 158 respectively assume their states indicated at stage ~ in FIG.ll.
Then, when the holding frame 108 is raised, the speed redud*ng mechanism starts with the accompaniment of only a ~ light impact as a result of the elastic cushioning action of >o the spring 110, which progressively returns towarcl its free state, its length becoming 11 as indicated at stage ~ in FIG.ll.
When the spring 110 returns to its free state at ; r~hich its length is lo, the spring 158, on the contrary, is .~5 ~ then compressed to assume the length 1'2 as indicated at stage ~ in FIG.ll. At this time, the interior of the space 114 is i released from its residual reduced pxessure state by the elastic force stored in the spring 158, whereby the holding ; frame 108 separates smoothly from the lower vessel 106, and, ~ at the same time, the load imposed on the worm gear of the ., ,~, ,1, 1 speed reducing mechanism is reduced. When the holding frame 108 is raised, all of the springs are restored to their original states as indicated at stage ~ in FIG.11.
Further, this invention is not limited to these embodiments but various variations and modifications may be made without departing from the scope and spirit of the invention.
1~
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invention to provide a novel and useful sheet overlaying fabrication process in which the above described difficulties have been overcome and an apparatus for practicing this process.
Another and specific object of the invention is to provide a process and apparatus for sheet overlaying fabrication in which a water-soluble adhesive ~s spray coated onto an article to be fabricated, and a sheet is bonded to the article by the adhesive thus coated. According to thè present invention, n a~r~é s-~cf~
~ ~a diluent and a surfactant are added to the water-soluble l adhesive, and the viscosity thereof is lowered, whereby automatic, continuous spray coating by means of a spray gun is possible.
Since the process is spray coating, uni~orm adhesive coating can be carried out even when the article being fabricated ~ has curved or bent surfaces, concavities and convexities, and the like. Furthermore, since the adhesive is water soluble, any adheslve adhering to the conveyer and the like can be readily removed by washing with water.
Still another object of the invention is to provide a process and apparatus for sheet overlaying fabrication in ~0 which the adhesive coated as described above is semidried in a relatively short time and, moreover, without causing thermal deformation of the article being fabricated.
A further object of the invention is to provide a process and apparatus for sheet overlaying fabrication in which, irrespective of the surface shape of the article to be fabricated, a thin thermoplastic sheet is bonded onto the surface of the article uniformly coated with an adhesive without producing shrinkage 7 wrinkles, and the like.
` Further objects and features of the invention will be apparent from the following detailed description when ,.
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li I
1 read in conjunction with the accompanying drawings, in which FIG.l is a plan view showing the general arrangement of one embodiment of an apparatus for carrying out a process step of spray COatillg an adhesive of one embodiment of the sheet overlaying fabrication process according to the invention and for carrying out semidrying of the adhesive thus coated;
FIG.2 is a side elevation orthogonal to FIG~l of the . same apparatus;
I FIGo3 is a partial perspective view of a part of the apparatus shown in FIGS~l and 2 at which a spray gun reverses its reciprocating motion;
FIG~4 is a partial perspective view of a part of the apparatus shown in FIGSol a~d 2 in which excess adhesive ~ flows off;
FIG~5 is a partial perspective view of a part of the apparatus shown in FIGS.l and 2 in which a conveyer bar washing device is provided;
FIG~6 is a perspective view of one example of a workpiece;
~0 FIGo7 is an elevation, with parts in vertical section, of one embodiment of a device for carrying out the step of bonding a sheet onto a workpiece coated with the adhesive of the embodiment of the sheet overlaying fabrication process according to the invention;
. I
FIGSo 8A through 8I are elevations, in vertical section~ respectively showing the operational states in operation sequence of the device illustrated in FIG~7;
FIG~ 9A and 9B are perspective views respectively . showing examples of spacers suitable for use in the device shown in FIGo7;
~ - 6 -1 FIG.10 is a perspective view of a pallet and its loading platform part of the device shown in FIG.7; and FIG.ll is a diagram for a description of the deform-ing actions of springs in a shock absorbing mechanism of the device illustrated in FIG~7.
An automatic adhesive applying device of one embodiment of a fabrication apparatus for carrying out the sheet overlaying fabrication process of the present invention will first be described with reference to FIGS.l through 5.
This automatic adhesive applying device 10 comprises a process section Pl for automatically applying an adhesive and washing of excess adhesive and a process section P2 for ; semidrying the adhesive. These process sections Pl and P2 are provided with first and second conveyers 12 and 13, respectively, which are contiguously disposed and driven by I a motor 14.
As will be apparent from FIGS.3, 4, and 5, the conveyer 12 is disposed between a pair of support rollers 16a and 16b.
The conveyer has a plurality of transverse conveyer bars 15 o supported at their ends in rotatable state at equal spacing intervals.
I As shown in FIG.4, each workpiece 17 is loaded with its surface to be processed on the upper side onto the conveyer 12 from the supply side ~ and is conveyed in the .~5 ~ arrow direction A. The workpiece 17 may be an aricle of complicat ed shape having, for example, a planar part 17a, a recessed park 17b9 side face parts 17c, and curved parts 17d, as shown in FIG.6. The material of the workpiece 17 is not limited `l to wood and wood products but may be any of other materials such as synthetic resins and metals. The workpiece 17 thus .j conveyed is spray coated with an adhesive by a spray gun 18 as described hereinafter.
Referring to FIGS. l and 2, compressed air at a primary air pressure of the order to 5 kg./cm2., which has been supplied from a source such as an air compressor (not shown) through an air hose 19, is passed throuyh an air filter 20 and a mist separa-tor 21, thereby being cleaned, and then, after being pressure regulated by a primary pressure reducing valve 22, is distributed and supplied to a pressure tank 23 and the air spray gun 18.
Within the pressure tank 23 is stored a water-soluble adhesive of a synthetic resin (e.g., vinyl acetate resin) emulsion type in a suitably agitated state, being pressurized under a pressure of approximately 0.5 to 1.5 kg./cm . and, moreover, being continually agitated. In general, a water-soluble adhesive has a high viscos-ity above lO,OOOcps. and cannot be used for spray coating. In the present invention, however, the viscosity is adjusted to a value of the order of 1,000 to 5,000 cps. at which spray coating is possible by lowerin~ it to a degree which will not impair the adhesive strength by adding a diluent, a surfactant, and the like ~0 to the adhesive. An aqueous solution of an acrylic substance having a low molecular weight wherein the viscosity of the aqueous solution is equal to or less than about 200 to 500 cps., for e~ample, is suitable for the diluent. A silicone surfac-tant is added to the adhesive thereby to prevent aggregation of the adhe-sive resin component on the surface of the wor]spiece to form particles after application of the adhesive and to reduce the sur-face tension of the adhesive surface to a value of the order of 20 to 40 dyne/cm. in order to improve the "wetting" pheno~enon.
A spreader is also added to the adhesive for the purpose of pre-venting "spattering" of the adhesive on the surface of the work-piece. The diluted water-soluble adhesive is ejected as a mist through the spray gun 18 by the pressure within thepressure tank 23 1 and the air spray pressure of the compressed air reaching the spray gun 18.
The spray gun 18 undergoes a traversing reciprocation ' in the transverse direction perpendicular to the traveling direction of the ~onveyer 12, being driven by a motor 25 through a crank 26 and guided by a guide 24 supported to extend transversely across and above the conveyer 12. Through the spray gun 18 thus undergoing this traversing reciprocating movement, the adhesive is ejected as a mist and is automatically spray coated on the upper face of each workpiece 17 being conveyed by the conveyer 12 and passing by the spray coating station as shown in FIG~4. Since the adhesi~e is applied by spray coating in this case, even when the workpiece 17 has a complicated shape, the adhesive is uniformly applied into all corners without skipped spots.
The speed of traversing reciprocation of the spray gun 18 is determined by setting the rotational speed of the motor 25 to an appropriate value in conformance with the traveling speed of the conveyer 12 so that the adhesive will '?0 be evenly applied. Furthermore, the traveling stroke of the spray gun 18 is set at a suitable value in relation to the width W of the workpiece 17 so that the spray gun will not reverse its traversing direction above the workpiece and -thus apply a double coating.
,~5 Any adhesive in mist form which has spread out and away from the workpieces 17 as a result of the spraying action of the spray gun 18 is discharged outside of the apparatus by `I a dust collector 27 provided with an exhaust fan (not shown).
Drainage devices 30a and 30b are disposed above the conveyer 12 and in the vicinities of the lateral edges thereof . _ 9 _ ,1 at respective positions in symmetrical opposition where the spray gun 18 reverses its traverse direction as indicated by the broken-line arrowO These drainage devices 30a and 30b are adjustably secured to a structural part of the apparatus by bolts 31 passed through slots 32 in parts of these drainage devices. Thus, the distance between these drainage devices can be adjusted to conform to the traversing stroke of the spray gun 18. The construction and disposition of the drainage device 30a is shown in FIG.3~ Since the drainage device 30b is of similar construction, its description will be omitted. The drainage device 30a has a draining inner surface 33 disposed with an inclination at the point of reversal of traversing move-ment of the spray gun 18 and a plate 34 for preventing scattering of adhesive. The height and the angle of inclination of the plate 34 are appropriately adjusted by means of wing nuts 35 in accordance with the degree of spattering of the adhesive due to the spray pressure, the ejection flow rate, and other factors.
The drainage device 3~a is supported at its one end by a bracket 36 and is provided with a water supply hose 37 for supplying a continuous supply of water, which is caused by the inclination ; of the draining inner surface 33 to flow therealong in the slight arrow direction.
The adhesive, which is being ejected from the spray gun 18 also when the spray gun reverses its traversing direction, is spxayed directly into the draining inner surface 33 and, at the same time, is sprayed onto the surface of the scattering prevention plate 34 to assume the form of drops which reach the draining inner surfaceO The excess adhesive which has thus reached the draining inner surface 33 is dissolved by the water supplied through the water supply hose 37 and is drained off via l i 1 ~ a drainage 38 and a drain pipe 3~ to the outside. The portions of the adhesive or the water which have spattered from the ; draining inner surface 33 at the time of the above described spraying of the adhesive are received by the scattering prevention plate 34 and thereby prevented from splashing onto the conveyer 12 and the workpieces 17. In this connection, the above mentioned spattering can be suppressed even more effectively by lining the draining inner surface 33 with a cushioning material such an urethane resin foam.
Thus, the adhesive ejected from the spray gun at the time of its reversal of traversing direction is effectively prevented from adhering directly to the conveyer 12.
In addition, as shown in FIG.4, a drainage pan 40 is installed between the upper and lower spans of the conveyer 12 at a position below-the spray gun 18. The interior of this drainage pan 40 is continually supplied with water from a water supplying hose ~1. Oversprayed adhesive is dissolved in the water flowing in the arrow direction in the drainage pan 40 and is discharged through a drain pipe 42 to the outside. Thus, adhesive which has been overspxayed to parts other than the workpieces 17 is prevented from adhering to the lower span of the conveyer 12 which is the return path thereof a~d, moreover, is discharged out of the apparatus.
A water vessel 45 is installed below the lower span of the conveyer 12 forming the return path thereof and is divided ~ into three separate vessels 46, 47, and 48 successively :` I
disposed in the travel direction of the lower span of the conveyer 12. These vessels 46, 47, and 48 are respectively provided with water supply hoses 52, 53, and 54 having at intermediate parts thereof water supply valves 49, 50, and 51 . ~
. I , ll l 1 , . . .. .
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1 and with water drain pipes 55, 56, and 57, whereby water is being contin~ally supplied into and drained from the interior of each vessel. That is, water is being continuously circulated ~. through all three vessels 46, 47, and 48.
The vessel 46 is provided thereabove with a fabric mop 58. This mop 58, which is continually sup~lied with water through the water supply hose 52, always contains an ample quantity of water, and excess water is dripping from its lower partO The vessel 47 is provided therewithin with a block of urethane resin foam 59 projecting upward to a height level where it contacts the conveyer bars 15 in the lower span of the conveyer 12 and containing an ample quantity of water. Further-more, the vessel 48 is provided similarly therewithin with a block of urethane resin foam 60. The water supply hose 54, which has a large number of flne perforations 61 formed therein, is laid over the upper surface of this urethane resin foam 60.
The conveyer bars 15 in the lower span of the conveyer 12 first contact the mop 58 as they travel past the vessel 46, and any adhesive adhering to the conveyer bars 15 is thus ~ dissolved and washed away. Next~ the conveyer bars 15 contact the upper surface of the urethane foam block 59 and rotate about their axes as they travel past the vessel 47, and any adhesive still adhering in dissolved state on the conveyer ~ars 15 is wiped off The conveyer bars 15 further contact the urethane foam block 60 and rotate as they travel past the last vessel 48, being subjected to a finishing water wash with water ejected from the fine perforations 61 of the water supply hose 54, and . any remaining adhesive still adhering to the conveyer bars 15 is completely removed. Finally, the conveyer bars 15 are wiped by a suspended sheet of dry cloth 62,whereupon the clea~ing ~ - 12 -., I
1 step is completed.
In this manner, all conveyer bars 15 o~ the conveyer 12 which have passed through the conveyer lower span are ' completely rid of ~he adhesive. Therefore, when the workpieces 17 are successively loaded onto the conveyer at the posi~ion X~
undesirable occurrences such as adhering of adhesive to the reverse side of the workpieces 17 to contaminate the same and sticking of the workpieces 17 to the conveyer bars 15 are prevented.
~ The workpieces which have been coated with adhesive in the above described manner are conveyed to the drying section of the apparatus, where the adhesive is semidried as described belowO Referring again to FIGS.l, 2, and 4, each workpiece 70 thus coated on its upper and side surfaces with the adhesive is automatically transferred at the downstream end of the conveyer 12 onto the conveyer 13, by which the workpiece 70 is thereafter convey~d in a similar manner in the arrow A direction~
Each coated workpiece 70 is thus conveyed first through a setting oven 71 and then through a lateral face drying oven 73 in which ~o far-infrared-ra~ heaters 72a and 72b are installed on respective opposite sides of the travel path of the workpieces 70. In this lateral face drying oven 73, the adhesive film applied on the lateral faces of each workpiece 71 is semidried. The workpiece 70 is then conveyed through an upper face drying oven 75 provided at the ceiling part thereof with far-infrared-ray heaters 74a through 74d, where the adhesive`film on the upper ~i face of the workpiece 70 is semidriedO Thus, the coating film on the late~al surfaces and the upper surface of each workpiece ~ 70 is semidriedO Finally each workpiece 70 is passed through and cooled by a cooling chamber 76 and is then conveyed to the ,1 " ~
~2~
I succeedin~ sheet overlaying process section.
The above mentioned far-infrared-ray heaters 72a, 7~b, and 74a through 74d emit far-infrared ra~s which are in the invisible light ray region. The molecules and atoms of the adhesive coating film undergo torsional vibration and stretching vibration as a result of irradiation by the far-inf-rared rays.
; As a result of the exothermic hardening energy thus generated, heating and drying take place instantaneously in a ve~y short time even to deep layer parts, and uniform semidrying is achieved over the entire coated surface and throughout the entire film thickness.
Accordingly, by using these far-infrared-ray heaters, the adhesive of low viscosity in its coated stated is promptly dried before it can flow into the concavities and the side of `low sloped surface of each workpiece 70, and the coated adhesive film is semidried in a condition wherein it is main-tained at a uniform thickness. Furthermore, since the drying time is short, and the temperature rise during this drying step is not very great, there is no risk whatsoever of warp-~0 ing of the workpiece 70 itself or deterioration of the its material~
The setting oven 71 and the cooling chamber 76 are respectively disposed in front of and after the drying ovens 73 and 75 and function to prevent heat emission from these dry-ing ovens. Thus, the adhesive coating film is efficiently dried with a small quantity of heat. Furthermore, the inher surfaces of the ovens 71, 73, and 75 and the cooling chamber 76 are lined with a material such as steel plates with mirror surface finish so as to minimize heat loss. In the middle of this ~ group of contiguously alined ovens and cooling chamber, an , exhaust duct 77 is provided to discharge vaporized substances I I
l - 14 -,, ~
1 ~ within the ovens out of the apparatus.
The temperatures of the far-infrared-ray heaters 72a and 74b are detected by heat detecting devices 78a and 78b re~spectively attached thereto and connected to a temperature regulator mounted on a control panel 79, the temperature regulator thus operating to control the temperatures within the drying ovens 73 and 75. The temperatures of ~he far-infrared-ray heaters 72a and 72b and 74a through 74d may be controlled ` separately.
Each workpiece 70 coated with the adhesive and semi-dried as described above is conveyed off the conveyer 13 and then, as shown in FIG.8A, is fixed to a pallet 101 over a jig 102. Over this, a thin decorative sheet 103 made of a thermo-plastic resin is placed in a covering manner, and this assembly is conveyed by a pallet conveying device 104 into a sheet bonding device 100.
This sheet bonding device 100 comprises essentially a base 105, a lower vessel 106 fixed to the base 105, an inverted upper vessel 107 which is movable up and down, the upper and lower vessels 107 and 106 being disposed in opposed positions with their concavities facing each other, and a holding frame 108 disposed between the upper and lower vessels 107 and 106 and adapted to be movable in the up and down direction, as shown in FIG.7. Across the holding frame 108 is stretched a rubber sheet 109 of a thickness of the order of 1 mm. made of natural rubber base material which has been so treated that it has flexibility, heat resistance, and stretchability.
The holding frame 108 is pressed in contact against the lower vessel 106 over packings llla and lllb interposed therebetween by the elastic force of springs llOo The upper , ~ .
,1 ~J2 ~
1 ~ vessel 107 is pressed in contact with the holding frame 108 over packings lllc and llld interposed therebetween by the elastic force o~ springs 112. Thus, a sealed space 113 is ~ormed between the rubber sheet 109 and the upper vessel 107, and a sealed space 114 is formed between the rubber sheet 109 and the lower vessel 106.
A heater 115 comprising essentially a thin plate o~
silicon rubber and electric heating elements of metal foil embedded in the silicon rubber plate is installed at the ceiling of the upper vessel 107 and operates to generate heat uniformly over its entire surface. On one hand, as shown in FIGSo 8 and 10, stops 116 for pallet positioning, which are adapted to be moved up and down by means such as an air cylinder, and a ~ pair of carriers 117a and 117b for raising and lowering pallets are installed within the lower vessel 106.
An air pipe line 118 is connected to the upper vessel 107 and communicates with the space 113 therewithin. This pipe line 118 is provided at an intermediate part thereof with an electromagnetic changeover valve 119, which can be operated 'o to communicate the pipe line 118 to one end of either of two branch pipe lines 120a and 120b. The pi~e line 120a is connected at its o~her end to an air ~ompressor 121, while the pipe line 120b is connected at its other end to a vaccum tank 123 connected to a vacuum pump 122. Similarly, a pipe line 124 ?5 is connected to the lower vessel 106 to communicate with thespace 114 therewithin. The pipe line 124 is connected also to an electromagnetic changeover valve 125 by which it can be interchangeably commlmicated to one end of either of two branch lines 126a and 126b respectively connected at their other ends to the compressor 121 and the vacuum tank 123.
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Il - 16 -Next, the sheet bonding operation of the above described sheet bonding device 100 will be described with re~erence to FIGS ~ 8A through 8I
I To start the device 100, a motor (not shown) is started, whereupon a chain 127 for raising and lowering is driven by the motor through a speed reducing mechanism (not shown) comprising a worm and worm g~ar and raises the upper vessel 107, which is guided in vertical movement by guide posts 128 at four corners thereof, to a height position Hl as shown in FIG~ 8A.
lQ The above mentioned motor continues to operate to drive a chain ; 129 for raising and lowering via another speed reducing mechanism~ The chain 129 thus raises the holding frame 108, which is guided by guide posts 130 in the upward direction Yl.
Interrelatedly with the rising movement of the holding i5 frame 108, the carriers 117a and 117b within the lower vessel 106 are raised by the operation of an air cylinder 131 as shown in FIGo 10 ~ whereby the pallet conveying device 104 for convey-ing in and a pallet conveying device 132 for co-nveying out are held at the same height position. Also interrelatedly with the rising movement of the holding frame 108, the stops 116 similarly rise to their operational position.
When the holding frame 108 risès to its highest rise ; position, it presses against the lower surface of the upper ; vessel 107, which has already risen as shown in FIG.8B, and the air-tight, sealed space 113 is formed. Simultaneously, ` the vacuum pump 122 starts, whereby the air within the sealed i space 113, passing through the large number of through holes in the heater 115, is evacuated through the pipe lines 118 and 120b. As a result, the rub~er sheet 109 is drawn into intimate contact with the lower surface of the heater 115 as shown in , .
;' - 17 -,"
.: .
1 FIGo 8C and is uniformly heated by the heater 1150 It is to be noted that the rubber sheet 109 is drawn against the heater 115 along a spacer 134 of triangular cross section as shown in FIG.9A without developing any locally stretched parts, whereby deterioration of the rubber sheet material due to local stretching does not occur.
At this time, the pallet 101 is conveyed ~ogether with the workpiece 70 by the conveying device 104 and, passi~g over stationary carriers 135 on the lateral sides of the bond-ing device, is conveyed into the lower vessel 106. The pallet 101 is arrested by the stops 116 and is positioned at a specific position on the raising and lowering carriers 117a and 117b.
As shown in FIG.10, the pallet 101 carrying and holding the workpiece 70 is guided by tapered entrance grooves 137a and 137b formed at the leading part thereof and fits onto the pair of carriers 117a and 117b. Guide grooves 136a and 136b formed contiguously with the entranGe grooves 137a and 137b in the pallet 101 are thus guided, whereby lateral movement of the pallet in the transverse direction perpendicular to the direction of travel is limited, and the pallet is thus smoothly conveyed on a plurality of rollers 138a and 138b provided on the carriers. Furthermore, a large number of through holes 139 are formed in the pallet 101. At the bottom part of the lower vessel 106, there is provided a lattice-like support frame 140 comprising an assembly of transverse spanning members in grating formO
When it is confirmed that the pallet 101 sent into j the lower vessel 106 has stopped at a specific position, the upper vessel 107 and the holding frame 108, which are iIl a unitary state in ~ their raised positions as indicated in FIG.8~, i , .~ , , , ;; . , descend as they are in the arrow direction Y2. Similarly, the ascending and descending carriers 117a ~nd 117b supporting and holding the pallet lOl together with the workpiece 70 and the I stops 116 descend, and the pallet 101 is pla~ed on the lattice-like support fr~ne 140. At this time, the rubber sheet 109 is still drawn against and adhering to the heater 115 and is heated thereby.
The upper vessel 107 and the holding frame 198 ~I descend in the unitary state until, as shown in FIG.8E, the l lower surface of the holding frame 108 is pressed against the upper surface of the peripheral lip of the lower vessel 106, and the sealed space 11~ is ~ormed by and between the lower vessel 106 and the rubber sheet 109 adhering to the inner wall surfàce of the upper vessel 107. Simultaneously with the ` formation of this sealed space 114, the air within the space 114 is evacuated through the pipe lines 124 and 126b, whereby this sealed space 114 is subjected to reduced pressure and placed in a substantially vacuum state. At this time, suction ; through the pipe line 118 is still being continuedO~
When the interior of the sealed space 114 thus assumes a substantially evacuated state, and the space be-tween `~ the uneven part with concavities and convexities of the work~
piece 70 and the decorative sheet 103 assumes an amply evacuated state, the first electromagnetic changeover valve 119 is changed .~5 1 over, and the pipe line 118 is communicated with the pipe line 120a. As a consequence, high-pressure air from the compressor 121 is supplied through the pipe line 118 to enter forcibly between the inner wall surface of the upper vessel 107 and the Il rubber sheet 109, whereby the rubber sheet, which has been heated ` by the heater 115, is subjected to this pressure and, separating ., .
,1 1 'I .
~2~
.` ~
., I
from the inner wall surface of the upper vessel 107, descends at a high speed. As a result, the rubber sheet 109 presses against the upper and side surfaces of the workpiece in intimate ~ conformance with the contour thereof, and the deco-rative sheet 103, being pressed by the rubber sheet 109, is caused to cover the adhesive covered surface of the workpiece 70 in intimate contact and conformance with this surface as shown in FIG.8F.
At this time, the sealed space 114 is still being held in a vacuum state through the pip~ line 124. In the above case, the s~ne result may be obtained by merely opening the pipe line 118 `
to the atmosphere.
Since the above described rubber sheet 109 still retains heat at this time, the decorative sheet 103 is heated ; uniformly by this heat and softened. As a consequence of this ~ softening effect operating together with the pxessing action of the rubber sheet 109, the decorative sheet 103 is easily deformed and, accurately conforming to the concavities and convexities in the contour of the workpiece 70, adheres closely to the workpiece at every nook of its contour. Furthermore, 'n the heat from the rubber sheet 109 is transmitted through the overlaid sheet 103 to the adhesive, whereupon the adhesive in semidried stabe softens, and it adhesion is restored. The decorative sheet 103 is thereby caused to adhere closely to ` the surface of the workpiece 70.
i When the first sealed space 113 has been pressurized for a specific time required for carrying out the above described intimate adhering operation, only the upper vessel 107 is moved upwards in the arrow direction Y1 as shown in FIG.8G, and the ~ rubber sheet 109 is exposed. At this time, the evacuation through the pipe line 124 is still being continued, and the '! ' : ~, ` . .
.
1 ~ flexible rubber sheet 109 is pressing the decora-tive sheet 103 against the surface of the workpiece 70.
Then, with these operational parts in this state, a cooling and static electricity removing device 141 additionally provided in the bonding device is operated to cause the flow a stream of cool ionized air against the rubber sheet 109. By this action, the rubber sheet 109 and the decorative sheet 103 are cooled, and, at the same timeS the adhesive sets. Thus, the decorative sheet 103 is bonded to the workpiece surface.
l When the decorative sheet 103 is thus cooled, ittends to shrink, but its free shrinkage is restricted because it is being pressed against the workpiece 70 by the rubber sheet 1~9. Accordingly, the decorative sheet 103 is bonded in a uniformly stretched ~ state onto the surface of the workpiece 70 without the occur-rence of any shrinking or crimping as in the past- Furthermore, since the cool air in the above mentioned stream is ionized7 any static electricity generated between the rubber sheet 109 and the decorative sheet 103 is removed, and the rubber sheet 109 is easily separated froM the decorative sheet 103 :in the >o succeeding process step.
The cooling and static electricity removing device 141 comprises a hollow cylindrical structure 142 made of an electro-conductive material and having a large number of small holes formed therein in the longitudinal direction and a central conductor 143 disposed at the center of this cylindrical structure. With a high voltage applied between the central conductor 143 and the cylindrical structure 142, high~pressure air is supplied into the cylindrical structure 142, whereupon ionized cool air is blown out at a relatively high flow rate through the small holes as indicated by the arrow ma-rks.
. .
1 ~ After the above described cooling has been carried out for a specific time,the electromagnetic changeover valve 125 is changed over, and high-pressure air from the compressor 121 is supplied through the pipe line 124 as indicated by the arrow in FIG.8H into the sealed space 114. As a consequence, the rubber sheet 109, which is free oE attractive force due to static electricity, separates easily from the decorative sheet 103.
Then, as indicated in FIG.8I, the holding frarne 108 ~ moves upward. Simultaneously, the carriers 117a and 117b move upward, and the pallet 101 ascends to the height of the pallet conveying device 132. Thereafter, the pallet 101 bearing the sheet overlaid article 144 with the decorative sheet 103 bo~ded thereto passes over stationary carriers 145 and is conveyed out 15 ~ of the bonding device.
With the above described fabrication procedure, one cycle of the sheet overlaying process steps is completed. The operation is continued by repeating the above described process steps respectively with respect to the workpieces successively conveyed into the above described sections of the apparatus.
In the above described sheet bonding device 100, a spacer 146 as shown in FIGo 9B may be pro~ided arolmd the periphery of the lower vessel 106O By the use of this spacer 146, local , I
stretching of the rubber sheet 109 at the time it is forced into ` close contact with the workpiece 70 is effectively prevented, i similarly as in the case of the aforedescribed spacer 134 Next, the structural organization and operation of spring mechanisms provided for the upper vessel 107 and the holding frame`108 will be described, but since the mechanism li 1 respectively on the two sides are identical, only that on the ,. I
left-hand side as shown in FIG.7 will be described.
The aforementioned coil spring 112 is accommodated ' within a guide stand 152 of hollow cylindrical shape fitted around a vertical guide rod 151, which is loosely fitted in a hole in a flange part of the upper vessel 107, the guide stand 152 being ixed to the upper part of the flange part, The coil spring 112 is thus interposed between the flange part and a ring or collar 153 on the guide rod 151. The upper and lower ends of the guide rod 151 are connected to the aforementioned chain 127.
~ Relative to the holding frame lO~, the first coil I spring llO is accommodated within a guide stand 156 of hollow . cylindrical shape fitted around a guide rod 155, which is loosely fitted in a hole in a flange part of the holding frame 108, the guide stand 156 being fixed to the upper part of the flange part~ The coil spring 110 is thus interposed between -the flange part and a ring or collar 157 on the guide rod 155. A second ` coi.l spring 158 is disposed around the guide rod 155 below '10 the holding frame 108 and interposed between the flange part and a ring or collar 159. The upper and lower ends of the guide rod 155 are connected to the aforementioned chain 129.
At the time of the above described operation of the sheet bonding device lO0, the coil spring 122 ~mdergoes a variation in its length as represented by Lo~ Ll> L2 . The ,, first coil spring llO undergoes a variation in its length as I represe-nted by lo~ ll> 12 ? while the second coil spring 158 undergoes a variation in its length as represented by ,. l'o~ 1 l> 1 2-~ First, the state of the sheet bonding device 100 as .
, - 23 -Il , ., 1 shown in FIG.8~ wherein ~he upper vessel 107 has been raised with the collar 153 arrested by the guide stand 152, and the holding frame 108 has been raised with the collar 157 arrested by the guide stand 156 will be consldered. In this state of the device 100, the lengths of the coil springs 112, 110, and 158 are Lo, lo, andl'o, respectively, as indicated at stage in FIG~
The holding frame 108 r~ses further and strikes against the lower surface of the upper vessel 107 as shown in FIG.8B and stops, but the motor and the speed reducing mechanism operate further and then stop. At this time, the springs 112 and 158 are compressed, -thereby cushioning the load due to abrupt stopping which acts on the speed reducing mechanism. At this time, the lengths of these springs 112 and 158 respectively become Ll and 1'2 as indicated at stage ~ in FIG~ and this sta~e is su;stained until the state indicated in FIGo 8D is reached. At ~is time, moreover, the upper vessel 107 and the holding frame 108 are being pressed togè~her over a packing interposed therebetween by the resilient forces of these springs 112 and 158, whereby the space 113 is positively maintained in an air-tight state.
The upper vessel 107 and the holding frame 108 are lowe~ed unitarily and, striking the lower vessel 106 and assuming the states indicated in FIGS.8E and 8F, come to a stop, but the motor runs further and then stops. At this time the ` springs 112 and 110 are compressed, thereby cushioning the suddenly applied load due to stopping which is applied to the speed reducing mechanism. Furthermore~ as the springs 112 and 110 are compressed, the separate second spring 158 becomes effective, and the lengths of these springs 112, 110, and 158 '- 2~ -1 becomes L2, 12, and l'o, respectively, as indicated at stage 1.
~ in FIG.ll. The resilient forces of the springs 112 and 110 at this time press the upper vessel 107 and the holding frame 108 down~ard, and the spaces 113 and 114 are respectively maintained in air-tight state.
When the upper vessel 107 rises from the state indicat-ed in FIG.8F, the elastic force of the spring 112 acts in the direction for lightening the rotational load imposed on the ~ motor and the speed reducing mechanism at the time of start-~ ing thereof~ and, after the spring 112 has fully returned to its free state, the weight of the upper vessel 107 acts for ~ the first time on the speed reducing mechanism. In the state : wherein the upper vessel 107 has moved to its raised position indicated in FIGS.8G and 8H, the springs 112, 110, and 158 respectively assume their states indicated at stage ~ in FIG.ll.
Then, when the holding frame 108 is raised, the speed redud*ng mechanism starts with the accompaniment of only a ~ light impact as a result of the elastic cushioning action of >o the spring 110, which progressively returns towarcl its free state, its length becoming 11 as indicated at stage ~ in FIG.ll.
When the spring 110 returns to its free state at ; r~hich its length is lo, the spring 158, on the contrary, is .~5 ~ then compressed to assume the length 1'2 as indicated at stage ~ in FIG.ll. At this time, the interior of the space 114 is i released from its residual reduced pxessure state by the elastic force stored in the spring 158, whereby the holding ; frame 108 separates smoothly from the lower vessel 106, and, ~ at the same time, the load imposed on the worm gear of the ., ,~, ,1, 1 speed reducing mechanism is reduced. When the holding frame 108 is raised, all of the springs are restored to their original states as indicated at stage ~ in FIG.11.
Further, this invention is not limited to these embodiments but various variations and modifications may be made without departing from the scope and spirit of the invention.
1~
~)o >5 ' ' .
, ~0 "
.. . ... .. .
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for sheet overlaying fabrication which comprises the steps of: spray coating workpiece which is caused to travel automatically, with a water soluble adhesive which, with added diluent and surfactant, has a viscosity of the order of 1,000 to 5,000 centipoises and a surface tension of the order of 20 to 40 DYNE/CM, semidrying the adhesive thus applied to the workpiece by radiation of far-infrared rays, placing a thermo-plastic sheet on the adhesive thus semidried, and pressing the thermoplastic sheet against the workpiece by a flexible and heat-resistant sheet which has been heated so as to soften the thermo-plastic sheet and is drawn by a vacuum, thereby to adhere the thermoplastic sheet closely to the surface contour of the work-piece in intimate conformance therewith.
2. A process as claimed in claim 1 in which, in the spray coating step, the water-soluble adhesive is applied by spraying by a spray gun adapted to undergo automatically a re-ciprocating movement in the transverse direction perpendicular to the travelling direction of the workpiece.
3. A process as claimed in claim 1 in which, in the spray coating step, the workpiece is caused to travel automati-cally and continuously by a conveyer, and any excess adhesive sprayed onto and adhering to the conveyer is removed by washing with water.
4. A process as claimed in claim 1, further comprising the step of cooling the thermoplastic sheet by a stream of ionized cooling air.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11541476A JPS5855822B2 (en) | 1976-09-28 | 1976-09-28 | Adhesive automatic applicator |
| JP115414/1976 | 1976-09-28 | ||
| JP11835376A JPS5343772A (en) | 1976-10-01 | 1976-10-01 | Apparatus for production of article overrlayed with sheet |
| JP118353/1976 | 1976-10-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124629A true CA1124629A (en) | 1982-06-01 |
Family
ID=26453914
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA287,678A Expired CA1124629A (en) | 1976-09-28 | 1977-09-28 | Process and apparatus for sheet overlaying fabrication |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1124629A (en) |
-
1977
- 1977-09-28 CA CA287,678A patent/CA1124629A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |