GB2223710A - Apparatus and a method for manufacturing a perforate synthetic resin floor mat - Google Patents

Description

1 - 2223710 EQUIRMENT AND A MIETHOD FOR WANUFACTURING A FLOOP MAT The

present invention relates to equipment and ' a mothod for. manufacturing a floor. mat, or, more, particularly to equipment and a method to obt,---ijri a perforated thick mat, made of soft synthetic resin usef ul in removing dirt., moisture, arid other materials adheting to the sole of a shoe.

A floor. mat which is laid at all entrance or a doorway floor of a building and is intended to provide an appropriate surface against which a person entering the building brushes the soles of Iiis shoes thereby removing the dust or molsture froni the soles, is often either made of a fiber having a fibrous surface like a carpet, or made of a metal or a hard synthetic resin having a plate-like surface with numerous penetrating perforations.

Of these two kinds, the mats having fibrous surfaces exhibit superior brushing effect on the shoe soles, and are thus more effective in removing dirt and water from the soles; however, they retain 1-1he dirt and water in themselves and the accumulated dirt iiijpaji-1!5 the resiliency of the surface fibers and 'thus weaken dus,t removal efficiency of the mats. On the other hand, the made, of hard synthetic resin having penetrating perrorations the m a 1, S are capable of' easily getting rid of the dust and water they remove arid receive fron, the soles of stioes -so that the surface, resiliency is not affected. But since the inherent resilienc;, hard synthetic resins in response to being trodden on is so low that walking on the mat, made of a hard synthetic resin is uncomfortable compared with the fibrous and is wore, the degradation in brus.hing effect. which -2occurs with time is more rapid than fibrous mats.

Under the circumstances, there- have been proposed composite floor mats which have the advantages of both a mat having fibrous surface and those of a mat made of hard synthetic resin with penetrating perforation.

Since such a composite floor mat is constructed such that brush-like hard hairs are densely provided in the vicinity of the perforations made in the mat of a metal or a hard synthetial resin, the mat becomes so bulky and heavy that it is not convenient to store or transport it, and since the brush-like hard hairs stand vertically to the mat surface, on. A backing plate is necessary to brushlike hard hairs which however renders it impossible to prevent accumulation of dust and dirt in the mat.

It is, therefore, an object of the invention to provide equipment and a method for manufacturing a synthetic resin floor mat with penetrating perforations in which the floor mat is a simply constructed thick floor mat made of soft synthetic resin with penetrating perforations.

it is not comfortable to walk support the thickly provided According to the present invention, the object stated above was attained through a method for making a perforated:F]Or:r mal. from a thermoplastic soft synthetic resin molded in the form of strings fused together side by side which are extruded from a plurality of nozzle units. This method adopts a first process means whereby the nozzle units closely arranged in a row on a T-die swing with the same periodicity and through a predeterniined swing angle in a predetermined manner; a second process m- eans whereby a conveyor conveys the extruded resin in the direction of -3the extrusion at a selected velocity; arid a third process means whereby selected nozzle cartridges are provided in the respective nozzle units. The said predetermined manner in which the nozzle units swing is such that every alternate nozzle unit in the row is controlled to swing in the same direction at qr time while every other riozzle unit is controlled to swing in the opposite direction at the same time, so that the soft resin strings extruded from the nozzle units and carried on the running conveyor look as if they were meandering and fuse with the neighboring strings at regular intervals whereby a net pattern is created. The conveyor is provided at a location immediately downstream of the T- die. More par'Licularly, this method comprises the steps of: (i) feeding thermally softened thermoplastic soft synthetic resin to the extruders; (B) extruding the resin from the nozzle cartridges of the nozzle units at a predetermined advancing velocity while the nozzle units are forced to swing in the said predetermined manner such that the extruded resin strings touch and fuse with the neighboring strings at regular intervals; (iji) conveying the extruded resin strings by the conveyor at a selective velocity; (iv) cooling the resin; and (v) applying desired treatment to 'the resin. According to the method of the invention, the nel, pattern created can be altered depending on the velocity of the conveyor relative to the advancing velocity of the extruded resin strings.

According to another aspect of the invention, the nozzle cartridges provided in the nozzle units are selected from various kinds of interchangeable cartridges having extrusion holes of diffelrent shapess and sizes. By employing at least two kinds of nozzle cartridges of different extrusion holes, it is poss-ible to obtain a floor inat. having i-rin urieven surface Cince the nozzle units ff irst proness means) closely -4provided on the T-die swing with the same periodicity but in the opposite direction to the neighboring nozzles units, the resin stVing extruded at the moment the swinging reaches extremity touches arie of the neighboring reshi string to fuse therewith. Arid since this takes place at regular intervals, a mat of scift resin of a net pattern having regiLlarly arranged perforations is obtained.

By controlling the conveying velocity of the extruded resin by means of the conveyor (second process ioeay--,g) in relation to the advancing velocity of the extruded resin, it is possible to modify the shape and the size of the perforations.

Furtberkijore, by arbitrarily selecting the nozzle cartridges (third process means), the cross section of the resin strings can be modified variously. Therefore, in various combinations of the second means and the. third means, a numerous number of arrangements are possible in the molding of the floor mat.

The Invention will be illustrated by reference to the Figures of which:

Fig. 1 is a block diagram of a preferred embodinient. of the -floor. mEI, manufacturing line to which the invention is applied; Fig. 2 is a plan view of a T-die employed in the line of Fig. 1; Fig. 3 is a longitudinal section of a nozzle unit employed in the line of Fig. 1; Fig. 4 shows an example of formation of mold extruded from the nozzle ef-, irt,ridges of nozzle units; Fig. 5 is a perspective view of a nozzle drive unit employedi in the line to which the invention is applied; Fig. 6 is a plan view of a fragment. or a floor rriat -5manufactured based on the. method of the invention; Fig. 7 is a perspective view Of a fragment of a floor mat of Fig. 6; Fig. 8 shows various examples of nozzle holes through which the mold is extruded according to the method of invention; and Fig. 9 shows various examples of the patterns of floor mats which are obtained according to the method of the invention.

Next, some of the preferred embodirtients of tile present invention will be explained with reference to the drawings described above.

Fig. 1 schematically shows a manufacturing line for a floor mat to which the method of the present invention is applied.

Thermally softened thermoplastic. soft resin, heated to a temperature between 150 and 200 IC, is fed in the extruder A. A generally f la t perf orated mold of thermoplastic sof 1. resin discharged front a T-dic B of the extruder A, which compresses the thermoplastic soft resin, is conveyed by a fence conveyor C whose conveying velocity is controllable, and carried thereby into a cooler. D corrprising a water tank. The perforated mold is cooled in the cooler D to solidify, and is driven, by means of rollers E provided immediately downstreani to the cooler D and rollers J pro-vided immediately upstream to a take-up reel K, to pass through a drier F, an applicator G for treatment with a plastisol, a drying furnace H, and a cooling room 1, whereby the perforated mold is cont;,niic)usl,, finished as the floor mat product and wound up on the 1.ak(.-up reel K.

Fig. 2 is a plan view of the T die B, wherein it!c, seen -6that nozzle units 1,, Ib... 11, - -. aligned to form a line normal to the. advance direction of the, mold are provided on the Main body of the T-die B. Preferably, 54 to qo nozzle url-tts are employed. These nozzle units are capable of swinging horizontally and shoultaneously in a manner that no two neighboring nozzle units are swinging in the same direction but, in the opposite directions such that the end of one nozzle comes in contact with the end of its right-hand neighboring nozzle when it swings to the right and its end comes in contact with the end of its left-hand neighbor when it swings to the Left. Fig. 3 is a longitudinal section of the nozzle urdt 1, and its peripheral parts in the T-die B. Reference numeral 2 designates a passage. for resin which leads to a expanded room 3. The resin passage I and the room 3 are made in a stationary main body 4 of the T-die B. The nozzle unit Ir, which is fixedly received in a nozzle port 6, and a fannel-shaped inlet port 7 are directly in communication with each other (Fig. 4). The nozzle unit I, is in a cylindrical shaft 8 which Is embedded in the main body 4 of the T-die B such that the cylindrical shaft 8 is freely rotatable on its axis, and the inlet port 7 is facing the expanded room 3. A narrow cylindrical portion 9b is integrally provided on one end of the shaft 8 to be received in a cylindrical hollow made. in a support plate 30b. On the other end of the shaft 8 is provided a narrow cylindrical shaft 93 which is received in a support plate 10a. The stipport plates 10a and 10b are fixed on the main body 4 by means of respective bolts 11a and 111). in the case of the nozzle 1,, as well as those nozzles which are located in every other positions from the nozzle 1,,, the narrow shift 9a penetrates the support plate 10a and carries on its end a f ixed gear 12. The gear 12 ineshes with a rack 13, pre-Cerably 60 to 9T hercinaf ter described.

As the Y-aek 33 reciprocates, the gear 12 if-, caused to turn one. way and then the other through a predetermiTied angle, whereby the cylindrical shaft 8 turns similarly. The expanded room 3 and the inlet port 7 are designed such that they are always in communication with each other regardless of the swinging movement of the shaft. 8. Hence the resin charged through the passage, 2 finds its way into the expanded rooni 3 and then pushed out from the nozzle unit 1,, like a snalte slithering, as shown in Fig. 4. The snaky mold 14 describes a locus within a predetermined width. Referring to Fig.

4, if the wold 14 thus discharged from the nozzle units and In 4 had a 'veloclty of advancing equal to the conveying velocity of the fence COTiveyor C, the mold 14 would have. formed a pair of symmetrical sine waves. However, if the conveying velocity of the fence conveyor C is increased a little, the mold 14 form a pattern shown in Fig. 4.

Since the. neighboring nozzle units swing in the opposite directions, they get in contact with each other at the end of every swing or at least, get in close proximity with each other such that the hot mold 14 discharged from the nozzle unit 1,, touches thc- hot mold 14 discharged from the nozzle unit],,, I wherel)y fusion takes place between them. This fusion makes it easier to form a pattern shown in Fig. 4 or more collectively in Fig. 6.

Fig. 5 shows the consLruction of an example. of a drive unit for controlling the swing movemerit of the nozzle units 1,]b... 3,... An electric motor 15 is equipped with a speed reducer 17 with a adjustment wheel 16 whereby the rotation of the shaft of the motor 15 is conveyed to the drive shaft, 18 at a reduced rate.

The drive shaft 18 is equipped with a bevel gear 19 at its end, which meshes with a bevel gear 20 locked on the middle part of a shaft 21. The shaft 21 carries two driving wheels 22a and 22b on its ends which drive respective crank levers 24, one lever held by a cylindrical shaft 23 provided on the outer face of the driving wheel 22b in the vicinity of the periphery thereof and the other crank held similarly at a position such that the phase difference from the crank lever 24 on the wheel 22b becomes 180". The crank levers 24 can freely rotate around the shafts 23.

Reference numeral 25 designates a pair of parallel slide frames each having a guide groove 26 therein. A slider 27 is received in each slide frame 25 so as to slide freely along the guide groove 26. Each slider 27 is connected with an end of the respective rack 13, and the same end of the rack 13 is provided with a cylindrical shaft holding one end of the respective crank lever 24 such that the crank lever 24 can freely rotate about the cylindrical shaft.

Although in Fig. 5 the whole arrangement is placed such that the pair of racks 13 lie horizontally, they are actually placed such that the racks lie in a vertical plane. One rack 13 meshes with one group of gears 12, and the other rack 13 with the other groups of gears 12. One of the gears 12 was explained with reference to Fig. 3. Now, in order for every alternate nozzle unit to swing -in the same direction, and every other nozzle unit to swing simultaneously in the opposite direction, the gear 12 of every alternate nozzle unit is provided on the. end of the narrow shaft 9a, for example, and the gear 12 of every other nozzle unit is provided on the end of the narrow shaft of 9b, which is extended beyond the plate 10b unlike the short one in Fig. 3.

When the motor 15 is switched on, the drive shaft 18 turns -9the bevel gear 19, which turns the Wheels 22a and 22b via thebevel gear 20. As the wheels 22a and 22b turn, the erank levers 24, 24 are pulled and pushed alternatively. When the crank lever 24 is pushed, the slider 25 is urged to slide in the guide 26 away from the wheel, and when the crank lever 24 is pulled, the slider 25 is urged to approach the wheel, whereby the rotational force of the. wheels 22a and 22b is transmitted to the racks 13 to cause them reciprocate such that while one rack is pushed away, the other rack is pulled in. Consequently, every alternate gear 12 turns in one. direction while every other gear 12 turn-, in the opposite direction during a stroke of the racks. 13, and in the next stroke of the racks 13 the rotational directions of the gears 12 are reversed. This kind of movement of the gears 12 causes the nozzle uriit--. 1,, lb... 1,.. - to move in a manner that no two neigIbboring nozzle un-its are swinging in the same direction but in the opposite directions such that the end of one nozzle cartridge comes in contact\ with the end of its right-band neighboring nozzle cartridge when it swings to the right and its end comes in contact with the end of its left-hand neighbor when it swings to the left.

Fig. 6 shows how the mold 14 continuously issued from the nozzle units 1,, 11,... 1,... shape when viewed from above. Fig. 7 shows a perspective view of the same, mold -14. The shape of the cross section of the mold 14 cari be. modified by changing the nozzle cartridges having different e> ftrusjon holes. The cross section of' the mole, 14 shown in Fig. 7 is a preferable example. Other examples of the nozzle, holes are shown in Fig. 8. Each nozzle cartridge can be interchangeably fitted in the nozzle port 6. It. is possible-to i. Lse one kind of nozzle cartridoe in every alternate nozzle Lu-iii. and a different kind of nozzle in every other JLOZZle tulit, or any other arrangement of the nozzle. cartrid,5ges is -10possible. The nozzle. cartridges are preferably made of stainless steel.

By modifying the conveying velocity of the fence conveyor C, it is possible to modify the pattern formed by the mold 14. Fig. 9 shows some of the patterns possible, of which pattern (PO) is the same as the one shown in Fig. 6, and is obtained wheri the conveying velocity of the. fence conveyor C is made slightly higher than the resin advancing (or progressing) velonity. When the conveying velocity is further increased over the. resin progressing velocity, the pattern becomes like that of (P1) in Fig. 9. When the difference between the conveying velocity and the resin progressing velocity approaches zero, the pattern becomes like that of (P2), which is a collection of sine and cosine curves W1hen the conveying velocity of the fence conveyor is made sufficiently lower than the resin progressing velocity, the pattern becomes like that of (P3).

Embodiment. I The raw material f or the floor mat is prepared by compounding 100 parts of polyvinyl chloride with 50 parts of a plasticizer, 2 parts of a stabilizer (antioxidant), and 0.1 part of a coloring agent.

Fifty-four pieces of nozzle uni'Ls were aligned on the T-die, the distance between the centers of the neighboring nozzles being 20mm.

The swing angle of each nozzle urjil, was 600. The die temperature was 180 - 185 OC; the die pressure was 60 kg/cirf; the extrusion pressure was 160 kg/cnI2; and the conveyor velocity was 70 cm/miri.

The mold was caught on a running horizontal mesh _11conveyor or a belt conveyor lest the shape Of the mold should change, since the mold extruded from the T-die is as hot as 170 - 185 OC. Then the mold was carried in-to a cooler.

The cooler D is preferably a water tank with sprayers wherein the mold is cooled with the water. sprayed from above as well as below till the temperature of the mold becomes room temperature.

The cooler D arid the subsequent process units are all equipped with roller conveyors. To maintain a constant conveying speed, it is effective to control the speed by means- of the drive rollers E and J.

The mold cooled by water spray is wet so that it is dried with the cool air or A thermoplastic polyvinyl chloride, is used In the case of polyvinyl chemically stable, and non-inflammable, hard to dielectric. The hardness of modifying the composition.

normal air blown f rom a drier F.

Sof t synthetic resin, preferably as the basic material for the. mat.

chloride (PVC), the mat is odorless, water-resistive. The PVC 111at is dissolve in an organio solvent and the mat can be controlled atwill by The resiliency is also obtained.

ill order to give gloss to the molded mat as we.]) as to improve the quality and durability of the mat, plastisol treatment is applied to the mat.

Plastisol treatment is primarily for quality improvement, and is not an essential treatment for manufacturing a f loor mat. There are various kinds of plastisols, but when the mat is made of polyvinyl chloride, vinyl plastisol is the most ef f ec;ti ve.

A vinyl plastisol of the f ol lowing composition is specially recommended:

1 1 polyvinyl chloride polyvinyl chloride paste resin plasticizer f iller stabilizer chiller pigment parts 50 parts 42.5 parts 5 parts 2 parts 0.5 parts 0.1 parts Preferably, the vinyl pJastisol is applied to the entire surface of the mold un1formly by means of sprayer units provided in the applicator G. A film of the vinyl plastisol is formed on the whole surface of the mold.

The mold coated with the plastisol in the applicator G is carried in the drying furnace H. The drying furnace H is a screen conveyor or a roller conveyor equipped with an internal heat source and is capable of curing the mold at temperatui7es between 150 and 160 "C - If the fusion takes place satisfactorily, the mold has glossy finish and the strength of the mat is reinforced.

The mat heated in the drying f urnace H was soft, and therefore it was brought horizontally into the cooling room 1, where the mat was cooled with cool air to normal temperature (20 to 25 OC). The cooled mat was cut to a predetermined length suitable f or a floor mat, as it was would up in the reel K.

The mat thereby produced looked as shown in Figs 6 and 7. The perforation became roughly a square. The cross section (hatched in Fig. 7) had a width of 2 min and a height of 15 mm. The space was 10 mrif. The mat width was 900 mm. The weight was 5.350 kg per square meter.

t Z Embodiment 11 The same raw material er-ind the same treattrient. pressure were used as in the case of Embodiment I. Only the conveyor velocity (pulling velocity) was set to 85 eni/min. Also, the extrusion pressure was set to 180 kg lei?i The resulting pattern looked like (P1) in Fig. 9. The perforation was roughly a rhombus, the ratio of the shorter diagonal to the longer diagonal being 1: 1.5. The weight was 4.900 kg per square meter.

Embodiment Ill The same raw material, equipment arid molding processes were used as in the case of Embodiment 1. Only the nozzle cartridge having a rectangular hole, 2 mm(w) X 15 mrii(h), was used. Since the upper surface of each belt is flat, the molded mat has a f lat surface on one side thereof. If the floor mat is laid with its f lat side up, a person walking on the floor mat feels flatness with the soles of his feet, and feels comfortable and his body does not receives shocks.

Embodiment IV Tilie same raw material, equipment and molding processes were used as in the case of Embodiment I. Only the nozzle. cartridge. used was a one having a circular hole of a diameter 5 mm. The distance between the centers of any neighboring nozzles was 20 mjij, and the width of the mat was 900 mm. The conveyor velocity was 80 cm/min. The weight of the resulting floo.- mat was 3.500 kg per square meter.

According to the invention, the riozzle units are aligned on the T-die widthviise and a first process means is adopted to force the nozzle wiits to swing simultaneously in such a manner -14thal. every alternate nozzle unit swings in the same direction while every other nozzle unit swings in the opposite d-irection, so that the molded resin extruded from each nozzle unit shapes like a snake slithering. It is possible to form a perforated mat from the thus extruded mold by letting the mold fuse with each other at the contacting points. By virtue of the fusion, the molded mat is reinforced.

Furthermore, since a second process means for controlling the conveyor's conveying velocity is adopted, it is possible to modify the-- pattern of the perforation (if the mat at will. Also, a third process means is adopted whereby the shape of the nozzle hole is changed, so that a wider variation is obtained in th--;pattern of the finished mat.

According to the invention, since the mold extruded is swung by means of the swinging motion of the nozzle units, it is possible to manufacture a thick mat of soft synthetic resin, which gives elastic and comfortable feeling to the person stepping on the mat. Due to the elasticity of the mat, the brus-Ifing effect of the mat is improved, and the dirt and moisture sticking to the sole of a shoe are easily removed from the shoe. Furthermore, the, removed dirt arid moisture fall to the floor through the perforation of the mat, so that little dirt remains kept in the mat and the performance of the mat is maintained for a long time without cleaning the mat. The mat of the invention is so simply constructed that it can be easily cleaned with water.

The mat of the invention is placed with one side on the floor, so that when water falls through the perforation, the draining water flows through the narrow space made between the mat and the floor. However, if the surface of the floor is very fiat, Z 1 -15it is dif f icuit -for the water to drain promptly. In order to facilitate the flow of the draining water, it is effective to provide a wider space between the mat and the floor, which is attained by an arrangement such that two or more kinds of nozzle cartridges are employed, of which one kind of the nozzle cartridges have holes that are shorter than others in their vertical length. The mold extruded from these nozzle cartridges of vertically shorter hole do not touch the floor thereby providing a drainage passage between the floor and the molded mat.

Claims (12)

Claims.

1. Equipment f or manufacturing a f loor mat from a I thermoplastic sof t synthetic resin having a resin extruder for formation of the floor mat comprising: (a) a plurality of nozzle units closely provided in a row across a T-die of the extruder unit and capable of- swinging with the same periodicity and through a predetermined swing angle in a manner such that every alternate nozzle unit in the row swings in the same direction at a time while every other nozzle unit swings in the opposite direction at the same time; (b) a conveyor to convey resin strings extruded from said nozzle units in the direction of the extrusion at a predetermined velocity; and (c) a plurality of interchangeable nozzle cartridges provided in the respective nozzle units.

2. Equipment for manufacturing a floor mat as claimed in claim 1 wherein said interchangeable nozzle cartridges consist of at least two kinds of nozzle cartridges having different extrusion holes.

3. A method for manufacturing a floor mat from a thermoplastic soft synthetic resin molded in the form of strings laid side by side which are extruded from a plurality of nozzle units comprising adopting a first process means whereby the nozzle units closely arranged in a row across a T-die swing with the same periodicity and through a predetermined swing angle in a manner such that every alternate nozzle unit in the row swings in the same direction at a time while every other nozzle unit swings in the opposite direction at the same time; and a second process means whereby a conveyor provided immediately downstream to the T-die conveys the extruded resin in the direction of the extrusion Z it -17at a predetermined velocity selected from various velocities.

4. A method for manufacturing a floor mat as claimed in claim 3 characterized by further adopting a third process means whereby selected nozzle cartridges are provided in the respective nozzle units.

5. A method for manufacturing a floor mat as claimed in claim 4 characterized by comprising the steps of: (1) feed-ing thermally sof tened thermoplastic sof t synthetic resin to the nozzle units; (ii) extruding the resin from the nozzle cartridges of the nozzle units at a predetermined advancing velocity while the nozzle units are f oreed to swing in the said predetermined manner such that the extruded resin strings touch and f use with the neighboring strings at regular intervals; (M) conveying the extruded resin strings by the conveyor at a predetermined velocity; (M cooling the resin, and (v) applying desired treatment to the resin.

6. A method for manufacturing a floor mat as claimed in wherein said predetermined velocity of conveying the resin is slightly greater than said predetermined velocity of the extruded resin.

A method for manufacturing a floor mat as claimed in claim 5 wherein said predetermined velocity of conveying the extruded resin is equal to said predetermined advancing velocity of the extruded resin.

8. A method for manufacturing a floor mat as claimed in clairri 5 wherein said predetermined velocity of conveying the extruded resin is slightly smaller than said predetermined advancing velocity of the extruded resin.

9. any one claim 5 extruded advancing 7 A method for manufacturing a floor mat as claimed in of claims 3, 4, and 5 wherein said thermoplastic soft v.

synthetic resin is polyvinyl chloride.

10. A method of making a mat substantially as described herein.

11. Equipment for making a mat substantially as described herein.

12. A mat whenever made by a method as claimed in any one of claims 3 to 10.

PublIshef I P90 atThe Patent Office. State House. 6671 High Holborr,, LondonWCIR4TP. Further copies maybe obtained from The Patent Office Sales Branch. St Mary Cray. Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187