DE2311074A1 - DEVICE AND METHOD OF APPLYING A SEAM - Google Patents

Description

Apparatus and method for applying a suture.

The invention relates to an apparatus and a method for continuous joining of layers by means of a hot melt adhesive sheet-like material along a seam as it moves forward this material in the direction of the seam. The invention is particularly for joining suitable of fabrics.

Usually fabrics are joined together along a seam, which is made by piercing with thread, the composition of the thread is similar to that of the fabric being sewn. With heavy fabric structures for the Industry is the appearance of the seam in terms of strength normally only of secondary importance, so that a stronger sewing thread can be used, regardless of the fabric to be sewn. For clothing fabric structures and other textile applications is both appearance and strength the seam of great importance so that the thread selection is essential is more limited. The use of a sewing thread made from a natural fiber together with Fabrics made from synthetic fibers or the use of a synthetic sewing fiber along with fabrics made from natural fibers often has an ugly effect The result is a corrugated seam that is slightly pulled apart even in locally stressed seam zones can be.

Various methods have been proposed to fabricate fabric material to be provided with a seam or hem using adhesive. For example, proposed a tape or strip between the layers to be connected to insert a hardened hot melt adhesive, which is then fed by melted by heat or by passing it through a high-frequency electric field whereupon the layers are pressed together. In a different procedure the layers are covered by threads or threads coated with a hot melt plastic Cords connected; in doing so, these threads or cords are placed between the layers of material arranged and heated, causing the coating to melt and bond the layers together.

In the known methods, difficulties arise in that the alignment of a separate tape or strip is not readily ensured is. Furthermore, if a separate tape or strip is required, the hot melt adhesive are initially squeezed in tape or strip form, whereupon it is then during the Gluing process is melted again and then cooled.

The present invention aims to provide a method and an apparatus to indicate continuously a seam or hem on a (woven or not woven) piece of fabric when it is moved in the direction of the seam. Included the seam is supposed to be formed when the arcuate piece is on itself is turned over with the raw edge of the material completely closed will. Another object of the invention is to make the seam in superimposed layers under Use of a hot melt adhesive to produce the adhesive strand is flattened and partially penetrates the pieces of material, making an extremely thin layer of adhesive separates the bonded layers and the material along it Holds edges together. Another object of the invention is to make seams on sequentially to form fed sheet material or the seams + are in continuous supplied webs of unlimited length, being either continuous or interrupted seams + are created.

In addition, the invention also aims to provide a method and a Specify device for the production of seams, which for different types of material required settings can be made without further ado, and where Differences in the porosity of the sheet material or in viscosity of the adhesive can easily be taken into account through different machine settings are. (Hems) In order to achieve the stated objectives in particular, according to the invention the combination of features mentioned in claim 1 or claim 5 is provided.

Furthermore, according to the invention to achieve the above and other objectives that provide a sequential sequence of operations is when one or more sheets of material run through the machine. The first will be over a layer for bonding or gluing in an aligned position put another layer. The layers are then moved past a nozzle where a strand of molten hot melt adhesive applied to a sheet at a point where the seam should be. If separate material pieces (material sheets) are to be provided with a seam, the nozzle is with equipped with a quick-acting valve, which the seam at predetermined points begins and ends with precision by noting the front and back rear edges of the piece of material. Then the seam quickly becomes a pair of Squeeze rollers - which can be heated if necessary - transported further, to the Adhesive strand on an extremely thin layer in between to spread the layers and to allow partial penetration of the adhesive into the Effect bow. In this position the adhesive hardens quickly to to avoid unwanted slippage or misalignment of the layers.

Further preferred embodiments of the invention emerge in particular also from the subclaims.

Further advantages, objects and details of the invention result from the description of an embodiment with reference to the drawing; in the drawing 1 shows a schematic perspective partial view of a preferred exemplary embodiment the device according to the invention; Fig. 2 is an enlarged perspective view part of the device shown in Figure 1; 3 is an enlarged side view the device shown in Figure 2; 4, 5, 6 and 7 sections along the lines 4-4, 5-5, 6-6 and 7-7 in Figure 3; Fig. 8 is a section through the nozzle and the valve for the hot-melt adhesive, with the valve piston in its open position is located; 9 shows a section of the nozzle and the valve, with the valve piston is in its closed position.

As can be seen in Fig. 1, sheets (pieces) 10, 10 'are made of flexible Material transported by means of a conveyor belt 12 from right to left. the end the drawings show that the sheet edge is simultaneously advancing a hem (seam) is formed will. The pieces 10, 10 'can expediently a fabric, for example a cotton fabric, used to make shirts will. Conveniently, the conveyor belt 12 is carried by one of the with a (not shown) Power source connected support roller 13 or 14 driven. Further are means provided which the pieces 10, 10 'in contact during their transport movement hold with the tape 12. These means can, for example, be in the form of a vacuum box Have 16; in this case the belt 12 is porous, i.e. the belt allows the vacuum be transmitted through. The vacuum box 16 is provided with a vacuum source (not shown) tied together. The use of any means to hold the pieces 10, 10 'in place on the conveyor belt 12 is therefore particularly useful in order to avoid misalignment of the pieces is avoided if this is done at the workstations described below be moved past. The gripping action exerted on the pieces is shortly before the Edge part of the pieces interrupted because this is used to form the hem. The hem edge portion is thus opposed over a width of at least 1 inch (2.54 cm) the edge free. Usually, however, it is convenient to have the grasping action as close as practically possible to the edge, with enough free edge part left to form the hem; this reduces the possibility that the Material loses its smoothness or becomes misaligned at the workstations. The pieces 10, 10 'are placed on the conveyor belt either by hand or by conventional means automatic sheet conveyors (not shown) laid. The conveyor belt 12 extends into the machine and passes to the folding station 20 and the Adhesive application station 22 and transports the pieces 10, 10 'into the Contact zone of the pressure and transport rollers, which ensure the movement of the sheets.

Although the invention here with particular emphasis on the hemming of individual, is described by the machine with small amounts of running pieces but it should be noted that the seaming of continuous pieces according to the invention possible is. In the drawing, the piece 10 is running straight through various work stations, while the piece 10 'follows closely behind. The pieces pass through first as they move forward from right to left an edge folder 23 sometimes referred to as a "trumpet". the Folding device 23 is attached to a carrier and is located in such a carrier Position that they are the edge part of the piece in the position shown in the drawing Way captured. When the edge of piece 10 passes through the folding device 23, will they are continuously folded by 3600, so that three layers of material on top of each other on the hem part available. A device can also be used to hold the material only folds around 1800; however, it is often expedient that there is no "raw" edge on the hem of the material is exposed. These folding devices are common in the art devices used.

The folding process described above brings a layer, namely the one the position indicated by reference numeral 30, in a position above and in alignment with a different position, namely with the flat part of the piece of fabric 10 at the edge. Although the layers 10 and 30 are in alignment at the exit of the folder 22 (compare Fig. 4) ', they are not connected and can do something about each other to apply the strand of adhesive from tube 40. The pipe 40 can expediently be a capillary tube or the like. And is with a fast-acting "Anti-drip" valve assembly 210 associated with an accurate start and an accurate Termination of the adhesive strand generated. The valve 210 is described in detail below described. When the sheets of material are hemmed in the manner described here or if for some reason a discontinuous seam is formed an electric eye or photocell 43 can be used to monitor the To determine a point for the piece of fabric being advanced to open valve 210 and close. It was found that when using sheet or sheet material is most conveniently used a photocell to the front and rear edge of the piece 10, 10 'to determine and around on this way Valve 210 to open and close. The photocell can be close or slightly offset be arranged opposite the tube 40.

If necessary, a suitable time delay device can be used in conjunction with this can be used to determine the exact switch-on and switch-off time of the valve 210 to ensure.

In the support plate 21 is for the passage of light to the photocell 43 a cutout 25 (see FIG. 2) is provided.

When the front edge of a bend is detected, the valve opens 210 and allows pressurized molten adhesive to flow through tube 40. The end of the tube 40 is round in shape and can either lightly touch the fabric or may be a small distance therefrom, as shown in FIGS. 3 and 5 is. When piece 10 is moved past tube 40, a strand of adhesive or Bead 53 evenly deposited thereon. To make sure the strand is right is placed, tube 40 actually extends at an angle in one piece fold in and separate layers 10 and 30 for a moment. Next the seam is moved into the contact zone of the rollers 50 and 52 which form the strand 53 Flatten and expand while the strand is still in its melted state is. The contact zone also causes the melted adhesive to be partially in the thickness of the layers 10 and 30 penetrates so as to ensure a good connection. The pressure rollers 50 and 52 can be heated by conventional heating means (not shown) to prevent the strand from hardening before it flattens and spreads. In some cases it is also useful to have the pressure rollers 50 and 52 12 synchronous with the conveyor belt / drive to move the pieces through the machine support.

The correct formation of a glue seam or a glue seam is by the properties of the hot-melt adhesive, such as viscosity, Melting temperature, curing time, etc., determined. It also makes good connections also determined by the properties of the material to be processed; Examples for these material properties are: openness of the fabric, v Art and binding the fabric, etc. It has been recognized that a large number of difficulties can be eliminated by reducing the distance between the application site of the adhesive strand 53 and the pressure rollers 50 and 52 precisely. In some In some cases it can also be useful to adjust the working temperature and pressure at the To control contact zone, which can be achieved by the usual controls. the The position of the pressure rollers 50 and 52 is with respect to the adhesive application device adjustable. The position can expediently by the provision of slots 54 and 56 can be changed, with the latter fastening bolts 55 and 57 extend. Furthermore, a suitable idle roller 58 can also be provided in order to take up the slack in the drive belt 59 as the rollers get closer to the glue applicator are arranged.

The fast-acting valve for controlling the adhesive strand can be of the type described in U.S. Patent 3,315,899. Such a valve is shown in Figs.

Arrangement 210 has a bore 211 for receiving a connector, which from a source of liquid, pressurized plastic adhesive comes. This connection can be made by thread 212. In body 210 is a second one Bore 213 is provided, which continues in a bore 214.

The bore 213 is at its outer opening by suitable means, sealed by a plug 216 screwed into the thread 217, for example. Finally, a third bore 218 is formed in the body 210, which the Bores 211 and 213 cuts and connects. Another hole 219 in the body 210 is shown running parallel to the bore 218 and stands with the bore extension 214 in connection. The bore 219 is at its upper end - as shown in FIG - Equipped with a counter bore 221. This counterbore 221 preferably has a much larger diameter than the bore 219. From the end face 223 the counterbore 221 from a blind bore 222 extends downward. The opening 224 connects the blind bore 222 to the outside of the body 210.

Means 225 can be connected to the opening 224, which means are optional Pressurized gas can bring in connection with opening 224.

A plug 226 is at 227 for sealing the bore 218 therein can be screwed in from the outside. The plug 226 has a hollow end 228 and a blind bore 229 extending longitudinally upward. Also in the stopper 226 transverse openings 231 are provided. There are preferably at least two vertical transverse openings 231 are provided, which connect the blind hole 229 to the outside of the plug 226, to allow adequate flow.

Filter means are expediently located between the bores 218 and 213 provided, which filter impurities from the hot melt. A special one suitable filter media is a cylindrical screen 232 inserted into bore 218 and at the top with the hollow plug 228 and at the bottom with the bottom the bore 218 is engaged.

A piston unit 233 is movable to and fro in the bore 219 arranged. The piston unit 233 consists of a lower part or a first in the bore 219 reciprocable piston 234 and an upper part or second piston 236 which engages with the counterbore 221. Between the Counterbore 221 and the upper piston part 236 a seal must be provided. A suitable sealing means is the O-ring 237, which is located in the upper part of the piston 236 provided annular groove 238 is seated. One that opens upwards, lengthways running blind bore 239 is provided in the piston 233. The upper end of the blind hole 239 must be sealed off, for example by means of a blind hole 239 screwed, threaded plug 241.

In the bore 219 is in the position of the bore extension 214 an annular groove 242 is formed. A second annular groove 243 is near the top of the Bore 219 provided to allow leakage through to communicate with the outside to expose standing opening 249. The piston 234 also has an annular groove 244 and transverse openings 247, which the bore 239 with the annular groove 244 and Consequently also connect to the outer surface of the piston 234. Connect transverse openings 248 the blind bore 239 running in the longitudinal direction with the one on the circumference of the piston 234 provided annular groove 246 and thus also with the outer surface of the cob 234.

A counterbore plug 250 is attached to the end of the counterbore 221 and seals it; the plug 250 is inserted by any suitable means, held in place by screws 252, for example. Means for optional admission of pressurized gas are passed through threaded opening 251 in the plug 250 shown.

A nozzle or distribution tube 40 is rigidly attached to the body 210 and has a chamber 254 that is larger in diameter than bore 219 owns and is aligned with it. A nozzle outlet 255 connects the chamber 254 with the outside of the tube 40.

Operation to Fig. 8 it should be noted that the bore 211 with a Source of pressurized hot melt adhesive. The hot melt runs through the openings 231 and enters the bore 229. Thus, the bore 218 will be filled with the hot melt that then flows through pressing the screen 232 to remove particles that do not flow through the nozzle. The hot melt then passes through the bore 213 and through the bore extension 214 to fill the annular groove 242. When the piston unit 233 is in its lowest Position is, then the annular groove 244 is in connection with the annular groove 242 and takes from there pressurized hot melt. That of the ring groove 244 supplied hot melt runs through the transverse openings 247 and thus into the Bore 239 in and leaves it through openings 248. From openings 248 from the hot melt fills the annular groove 246 and the chamber 254, whereby finally the hot melt is forced out through the nozzle outlet 255.

When the nozzle is to be turned off, it will be pressurized Gas admitted into the counterbore 221 via bore 222 and openings 224, whereby the piston unit 233 is raised into the position shown in FIG. It it should be noted that the bottom edge 256 engages the bottom of the bore 219 and seals the bore before the piston unit 233 reaches its uppermost position Has. In this way, the hot melt that is under pressure is now no longer available more in connection with chamber 254. When the piston unit 233 is further raised there is a pressure drop in the chamber. This pressure drop in chamber 254 endeavors to bring the hot melt back into the chamber at the nozzle outlet 255 254, which results in a sharply defined clipping. If the Piston unit 233 reaches the position shown in FIG. 9, the annular groove is stationary 246 is no longer in communication with the chamber 254, and neither is the annular groove 244 more connected to the bore extension 214. The operation of the piston unit 233 can be controlled by an electric eye 43. Other means of control the operation of the piston are fluidic devices, microswitches, etc .; the Operation can also be controlled manually. These controls regulate the flow of the pressurized gas to connections 225 and 251.

Molten adhesive is passed through inlet 212 of valve 210 a system such as is shown in FIG. 1, for example. Pellets out thermoplastic adhesive are added to the hopper 60, from where they a conventional melting device, such as an extruder 62, entered will. These melters are commercially available. The melted glue is fed through a pipe 64 to a pump 66, which is preferably of the positive displacement type and is, for example, a gear pump. The pump 66 is driven by a drive shaft 67 driven by a power source (not shown). From the outlet of the pump is the molten adhesive is fed via line 68 to the valve nozzle assembly. Furthermore, heating coils (not shown) in suitable places be arranged between extruder 62 and valve-nozzle arrangement; in most cases it is advisable that you at least on the adhesive lines between the extruder and nozzle provides insulation. A pressure relief valve can also be installed in the line be placed between the pump and the nozzle in order to avoid excessive pressure increases, which would occur when the valve 210 is closed.

Although the method according to the invention and the device according to the invention can be used with different types of hot melt adhesives, be a particularly useful one, suitable for use with fabrics Adhesive described below. (See US Pat. 3669921) These preferably suitable hot melt adhesive composition comprises a copolyester, of the following components (1), (2), (3) and (4) or ester-forming derivatives it is composed of: (1) terephthalic acid (2) adipic acid (3) ethylene glycol (4) 1,4-butanediol, with the acid components and the diol components in a molar ratio of 1: 1 are present, and wherein the copolyester has a molar ratio of terephthalic acid: Adipic acid in the range of about 60:40 to about 80:20, a molar ratio of ethylene glycol: 1,4-butanediol in the range of about 60:40 to about 80:20, a softening point in the range of about 600F to 3200F and an inherent one Has a viscosity of at least 0.5, measured at 250C using of 0.25 g of copolyester per 100 ml of a solvent that is 60% by weight Phenol and 40 percent by weight tetrachloroethane.

It is provided according to a preferred embodiment, that a hot melt adhesive composition of the copolyester defined above except that the molar ratio of terephthalic acid: adipic acid is about 75:25 and that the molar ratio of ethylene glycol: 1,4-butanediol is about 75:25 with the softening point being within the range of about 900C - 1500C and the inherent viscosity at least 0.7, preferably about 0.85 is.

In a particular aspect, the hot melt adhesive composition comprises from the four ingredients mentioned above 0.10 - 2.0 percent by weight (based on the weight of the copolyester) of an additive, which is either titanium dioxide or Is sodium stearate. Adding titanium dioxide or sodium stearate to the copolyesters considerably reduces the deterioration in joint strength due to aging.

The copolyesters mentioned can be produced by customary production processes be generated. See, for example, British Patent 1,047,072. For example, these polyesters by using such amounts of terephthalic acid, Adipic acid, ethylene glycol and 1,4-butanediol and under such polymerization conditions be prepared to result in a copolyester in which the molar ratio of terephthalic acid: adipic acid in the range of 60:40 - 80:20 and the molar ratio of ethylene glycol: 1,4-butanediol is in the range of 60:40 -80:20 while the inherent Viscosity (I.V.) is greater than 0.5 and preferably 0.7. The following was found: The higher the I.V. of the copolyester material, the greater the resulting Bond strength when laminating (joining) fabrics and other supports. In general, copolyesters are characterized by the following molar ratios: Terephthalic acid: adipic acid in the range of 60:40 - 80:20; Ethylene glycol: 1,4-butanediol in the range of 60:40 to 80:20, by softening points in the range of approximately 1750F up to about 3200F.

For some typical compositions the following table gives that Molar ratio of terephthalic acid: adipic acid, of ethylene glycol: 1,4-butanediol, the softening temperature and the inherent viscosity.

Mole percent of acid and glycol components copolyester terephthalic acid / Ethylene Softening I.V.

Adipic acid glycol / point 1,4-butane-C diol 1 60:40 60:40 80-85 1.27 2 70:30 70:30 130-135 1.09 3 80:20 80:20 153-158 1.16 So far, terephthalic acid has been used and adipic acid referred to; if desired, however, derivatives of such can also be used Acids are used. Examples of such derivatives are the acid - anhydrides, Esters and acid chlorides of such acids.

For example, dimethyl terephthalate can be used in place of terephthalic acid and dimethyl adipate can be used in place of adipic acid. In the same way For example, derivatives of ethylene glycol and 1,4-butanediol can be used to advantage.

Another method consists in making a diester of adipic acid and the 1,4-butenediol and then the diesters with polyethylene terephthalate mixes. This mixture is then melted and reduced at 485 ° F to 535 ° F Pressure polymerizes until the inherent viscosity of the polymer product is at least 0.5 is what is measured at 250C in a solution containing about 0.25 g of the polymer in 100 ml of a solvent that consists of 60% phenol and 40% tetrachloroethane consists. The polymerization is carried out under such conditions that the resulting copolyesters a range of Molar ratios of terephthalic acid: adipic acid from 60:40 to 80:20, a range of ethylene glycol: 1,4-butanediol molar ratios from 60:40 to 80:20 and an I.V. value greater than 0.5. It can also Titanium dioxide are introduced, namely by copolymerization of adipic acid and 1,4-butanediol with waste polyethylene terephthalate containing such an additive; alternatively, sodium stearate or titanium dioxide can be introduced into the polymerization mixture in which the copolyester is produced.

If desired, dyes or dye-accepting agents, Color stabilizers and various other additives to copolyester adhesives can be added to meet certain specific application requirements. These additives are usually added as such to the polymerization mixture, in which the copolyester is produced.

When copolyesters prepared in the manner described above as Hot melt adhesives are used for laminating various fabric systems, so As already indicated, excellent connections result. These connections are extremely resistant to the effects of cleaning agents Solvents such as perchlorethylene. Lined according to the invention Fabrics have good handling properties.

Typical operating conditions for the device described can For example, the following: Type of material: Woven cotton bedding Conveyor speed: 28 ft / minute pinch rollers: Made of metal and 1 inch (2.54 cm); spaced 4-6 inches (approximately 10-15 cm) from the Adhesive Applicator Nozzle Orifice Size: 0.027 in. (0.686 mm) in length of the nozzle tube: 1.5 in. (3.82 cm) Viscosity of the hot melt adhesive: 125,000 cps Temperature near the point of application: Approximately 400 ° -425 ° F Amount of Adhesive Dispensed: 20 Cubic Inches / Hour Hot Melt Adhesive: Copolyester of the type described above

Claims (12)

Patentenspcünhe 1. Device for the continuous formation of a Adhesive connection line between superimposed layers of sheet material, in which a path of movement for the material forming means and guide devices are provided, which are arranged in the trajectory and the arcuate Material in an overlaid and aligned position with another Bring position for the purpose of connection, characterized by a tube (40), whose one end extends between the aligned layers (10, 30) and substantially ends at the point of the desired line connection and relative to a position of the Material is arranged so that the flow of a viscous liquid of the opening is caused by the movement of the sheet material to be longitudinal the aforementioned position of forming a strand of hot melt adhesive a source of hot melt adhesive connected to the tube (40) a valve (210) positioned between the source and the tube (40) to control the flow of the hot melted adhesive through the pipe as a result of given signals to start and finish quickly and accurately, and by means (50.52) to after to press the layers (10, 30) firmly against each other before applying the adhesive strand. 2. Apparatus according to claim 1, characterized in that the guide means (23) at the edge of the web the edge portion 0 of the sheet material 360 to Fold over to form a three-ply hem, and that means for forwarding the sheet material are provided along the path. 3. Apparatus according to claim 1 or 2, characterized by devices (43) to determine the leading and trailing edges of the conveyed along the track sheet material, and opening and closing devices of Valve when detecting the front and rear edges. 4. Apparatus according to claim 1 or 2, characterized in that the means for firmly pressing the layers against one another are a pair of cooperating ones Have pressure rollers (50,52). 5. Device according to one or more of the preceding claims, characterized in that the end of the tube (40) lightly contacts the fabric. 6. Device according to one or more of the preceding claims, characterized in that the end of the tube (40) is a small distance opposite the substance (Fig. 3 and 5). 7. Device according to one or more of the preceding claims, characterized in that the tube is inclined at an angle into the fold extends into it. 8. Device according to one or more of the preceding claims, characterized in that the distance between the adhesive application station and the rollers (50,52) is adjustable (54,56; 55,57). 9. Method of forming an adhesive bond line between superimposed layers of sheet-like material, characterized by the following Steps: a) Feeding the sheet material forward along a predetermined one Web, b) superimposing the layers of sheet material and aligning them the layers for bonding, c) extruding a strand of molten hot melt Adhesive between two of the plies along the line of a desired seam while the sheet material is transported forward, J d) Forward transport of the sheet material into the contact zone of a pair of pressure rollers, and although before the adhesive hardens, whereby the adhesive strand at least is partially flattened between the layers. 10. The method according to claim 9, characterized in that the material is transported forward in individual, spaced apart pieces. 11. The method according to claim 9, characterized in that the arcuate Material is a fabric and that the strand is caused by the pressure rollers will partially penetrate the fabric. 12. method of forming a seam in sheet material; in particular according to one or more of claims 9-11, characterized by the following Steps: a) Feeding the sheet material forward along a predetermined one Train; b) folding over the edge portion of the sheet material by approximately 3600, in this way three layers of the material in a superimposed position and to bring in alignment for the connection; c) Injecting a strand melted hot melt adhesive between two of the layers along the desired length Connection line while the sheet material is advancing will; d) forward transport of the material into the contact zone of a pair of pressure rollers, and that before the hardening of the adhesive, whereby the adhesive strand at least is partially flattened between the layers.