Description

MANUFACTURE AND APPARATUS FOR SAFETY GARMENTS

USING ULTRASOUND FUSION

Technical Field

[1] The present invention relates to a method and an apparatus of manufacturing airtight safety garments via ultrasonic welding, and more particularly, to a method and an apparatus of manufacturing safety garments by heating and melting synthetic fiber sheets at a melting point or higher via ultrasonic welding and then pressing the fiber sheets against each other to bond them together. Background Art

[2] In general, the safety garments are used to protect wearers from harmful environments caused by operations in specific work places or from the work places themselves. The safety garments block dusts or minute chemical toxic materials, which are liquid or gas suspending in air, from directly contact the bodies of the wearers while allowing sweat and heat, which are created from the human bodies during the operations, to emit out of the garments, thereby improving amenity and enhancing operation efficiency.

[3] That is, the safety garments serve to protect workers from the harmful environments and improve the amenity of the operations thereby improving working efficiency. Accordingly, demands for the safety garments are expected to increase from now on due to increasing safety consciousness of labor unions or employers.

[4] Recently, workers evading from the harmful environments together with public relations and safety standards enhanced by the government have been increasing work places where the safety garments should be worn as well as improving the quality of the safety garments. In addition to a simple function of blocking the infiltration of external materials, water repellency has been reinforced to actively emit sweat and energy, created by the workers, out of the safety garments. Fiber sheets of the safety garments can block the infiltration of external materials and have fine pores capable of emitting sweat and heat.

[5] A typical manufacturing process of the safety garments includes steps of examining fiber sheets, designing a pattern via CAD, printing the pattern, marking the pattern on the fiber sheets, cutting the fiber sheets according to amounts to be manufactured, sewing the cut fiber sheets using pattern pieces and raw materials, and thermally bonding sewing portions with a seam sealing tape to achieve safety garment products.

[6] In the case of manufacturing the safety garments by a common sewing method, the fiber sheets are sewn with sewing threads. However, if the pressure of a presser foot,

the tension of the sewing threads and the type of the fiber sheets are not properly combined, undesirable small wrinkles, which are also referred to as puckering, are formed around a seam of a sewing line.

[7] Since dust or chemical material may infiltrate via seams into the safety garments, a seam sealing process is carried out to thermally bond the seams. However, it is very difficult to perform the seam sealing to those portions having puckering. Accordingly, final products should be discarded as inferior goods even with a simple error. This is the majority of loss expense and at least 70% of labor costs. Therefore, there are urgent demands for a noble method of manufacturing the safety garments, which can overcome such problems to improve productivity. Disclosure of Invention Technical Problem

[8] The present invention is devised to provide to a method and an apparatus of manufacturing safety garments, by which a problem of defective sewing due to seam puckering caused by the pressure of a presser foot and characteristics of fiber sheets can be overcome.

[9] The present invention is also devised to provide a method and an apparatus of manufacturing safety garments, by which defects caused in a seam sealing process which thermally bonds seams with a seam tape can be overcome.

[10] The present invention is also devised to provide a method and an apparatus of manufacturing safety garments, by which productivity can be economically improved and labor costs can be saved through a process much simpler than common sewing processes.

[11] The present invention is also devised to provide a method and an apparatus of manufacturing safety garments, which are endurable against repeated bending of welded portions and usable even after being washed repeatedly. Technical Solution

[12] According to an aspect of the present invention, there is provided a method of manufacturing safety garments via ultrasonic welding. The method of the present invention includes:

[13] (a) feeding two fiber sheets;

[14] (b) automatically aligning edges of the fiber sheets so that the fiber sheets overlap partially with each other;

[15] (c) adjusting a height of a pattern roller according to a thickness of overlaps of the fiber sheets; and

[16] (d) transmitting energy to the pattern roller, by an ultrasonic generator, to weld and bond the overlaps of the fiber sheets.

[17] In addition, the method of the present invention may further include, after the step

(b), trimming a portion of the fiber sheets, if the edges of the fiber sheets are not correctly aligned, in order to align edge ends of the fiber sheets.

Advantageous Effects

[18] The apparatus of manufacturing airtight safety garments via ultrasonic waves of the present invention can adopt ultrasonic welding to omit one step from a two step process which includes sewing and seam sealing to manufacture the safety garments, thereby eliminating reasons of defects that otherwise have occurred in the seam sealing step.

[19] The apparatus of manufacturing airtight safety garments via ultrasonic waves of the present invention can save labor expenses and material costs by bonding fiber sheets of the safety garments via ultrasonic welding and thus decrease the unit cost of products as well as enhance yield per unit time, unlike the prior art where at least 70% of labor costs are consumed in the seam sealing step and material costs increase due to high seam sealing costs.

[20] Furthermore, the apparatus of manufacturing airtight safety garments via ultrasonic waves of the present invention can be also used to manufacture elbow and knee portions which are repeatedly bent. The safety garments manufactured by the apparatus of the present invention have excellent washproof properties and can protect cross-linkage so as not to be broken by water, thereby preventing the filtration of liquid or gaseous foreign materials. Brief Description of the Drawings

[21] FIG. 1 is a flowchart illustrating a method of manufacturing safety garments of the invention;

[22] FIG. 2 is a flow diagram illustrating method of manufacturing safety garments of the invention;

[23] FIG. 3 is a perspective view illustrating an exemplary embodiment of the automatic alignment device shown in FIG. 2;

[24] FIG. 4 is a perspective view illustrating another exemplary embodiment of the automatic alignment device shown in FIG. 2;

[25] FIG. 5 is a perspective view illustrating the ultrasonic welder shown in FIG. 2; and

[26] FIG. 6 is a perspective view illustrating welded fiber sheets.

[27] <Major Reference Signs of the Drawings>

[28] 11: feed roller

[29] 13: separator

[30] 15: automatic alignment device

[31] 17: automatic trimming device

[32] 21: ultrasonic generator

[33] 31 : pattern roller

Best Mode for Carrying Out the Invention

[34] Hereinafter, a method and an apparatus of manufacturing airtight safety garments via ultrasonic welding will be described in detail in a stepwise fashion.

[35]

[36] (a) Feeding two fiber sheets

[37] Step (a) is carried out to steadily feed fiber sheets. The fiber sheet is raw materials to be fabricated into safety garments, and mainly composed of a synthetic fiber. The fiber sheet may also be implemented with a multilayer structure of different materials. However, corresponding portions of the fiber sheets to be welded together should be composed of synthetic fiber so as not to be properly welded.

[38] In general, available examples of the fiber sheets include polyolefin, polyester, nylon, PVC and so on, and have a thickness ranging from 0.5mm to 20mm so that both thin and thick fibers can be used. However, this is not intended to limit the resent invention.

[39] Generally, two fiber sheets are fed and then connected together to produce safety garments. The fiber sheets can be fed with end portions in the same direction partially overlapping so that edges overlap with each other as shown in FIG. 3. Alternatively, the fiber sheets can be overlapped completed as shown in FIG. 4 so that edges thereof can be welded together.

[40] The fiber sheets can be fed automatically by feed rollers 11 as shown in FIG. 2.

The feed rollers 11 can be provided in a plural pairs so as to feed the two fiber sheets respectively. The feed rollers 11 hold a fiber sheet to feed the fiber sheets at a predetermined speed.

[41]

[42] (b) Automatically aligning edges of the fiber sheets so that the fiber sheets are overlapped partially.

[43] Step (b) is carried out to feed the fiber sheets, which are held by the feed rollers, and automatically aligning the edges of the fiber sheets to partially overlap with each other. In the case of automatically feeding two fiber sheets, it is rare that edges of the fiber sheets are properly aligned. Therefore, an automatic alignment device causes the fiber sheets to engage with each other a preset degree so as to be manufacturable.

[44] An exemplary automatic alignment device 15 is shown in FIG. 3. The automatic alignment device 15 shown in FIG. 3 includes a first feed plate 151, which is configured planar to support one of the fiber sheets on a plane and has one folded edge, and a second feed plate 152, which is configured planar to support the other one of the

fiber sheets on a plane and has one folded edge.

[45] As shown in FIG. 3 (a), the first feed plate 151 has a generally planar configuration except for a U-shaped edge. That is, the U-shaped edge forms a folded first guide 153, which comes into contact with an edge of a fiber sheet to act as a guide so that the fiber sheet can be discharged correctly. Likewise, the second feed plate 151 also has a second guide 154 defined by a folded edge.

[46] As shown in FIG. 3(b), the first guide 153 of the first feed plate and the second guide 154 of the second feed plate overlap with each other at the output sides so that a fiber sheet A is fed to the first feed plate 151 and a fiber sheet B is fed to the second feed plate 151. In this fashion, the fiber sheets are outputted, overlapped with each other at a predetermined overlap width.

[47] In addition, the feed plates 151 and 152 of the automatic alignment device are configured to overlap with each other at the output sides as shown in FIG. 3 (a) but separated from each other to a predetermined distance at the input sides (i.e., portions where the fiber sheets are fed) so that the fiber sheets can be fed in a completely separated state. This, as a result, defines paths for the fiber sheets to converge together at the output sides. Although the fiber sheets can be fed as separated to the right and left as shown in FIG. 3 (a), it is not intended to limit the present invention. The fiber sheets can also be fed as separated vertically as shown in FIG. 3(b).

[48] In order for the fiber sheets to converge at the output sides but be conveyed in the separated state at the input sides as mentioned above, the fiber sheets can be fed respectively along the separate paths as in step (a) or a separator 13 as shown in FIG. 2 can be used.

[49] The separator 13 is configured to separate the fiber sheets from each other when the fiber sheets are fed at the same time along the same path. The separator 13 is wedge shaped to separate the fiber sheets into upper and lower ones. Then, the fiber sheets are separated vertically to move along upper and lower paths, and then inputted respectively to input sides of the automatic alignment device as shown in FIG. 3.

[50] Another embodiment of the automatic alignment device is shown in FIG. 4. The automatic alignment device 16 shown in FIG. 4 is configured similar to that shown in FIG. 3. That is, the automatic alignment device 16 includes a first feed plate 161, which is configured planar to support one of the fiber sheets on a plane and has one folded edge, and a second feed plate 162, which is configured planar to support the other one of the fiber sheets on a plane and has one folded edge, a first guide 163 and a second guide 164.

[51] In the automatic alignment device 16 shown in FIG. 4, the same edges of the fiber sheets in an overlapped state can be welded together. For this purpose, the first and second guides 163 and 164 are arranged in the same direction.

[52] FIG. 4(a) shows the guides with the output sides overlapped with each other and the input sides diverged to the right and the left so that the fiber sheets can be fed along different paths. Referring to FIG. 4(b), the output sides are overlapped with each other but the input sides are diverged vertically.

[53]

[54] (bl) Trimming predetermined portions of fiber sheets to correctly align edge ends of fiber sheets

[55] In step (bl), the edge ends of the fiber sheets are cut clearly in order to facilitate next step. In a state where the two fiber sheets automatically are aligned in step (b), the edges of the fiber sheets are ultrasonically welded. However, in the case of feeding the respective fiber sheets in an overlapping position, edge ends of the fiber sheets may not be aligned properly. If the fiber sheets are thin, the edge ends may be outputted in a folded state. Accordingly, this step can be performed to trim the edge ends with the automatic trimming device 17.

[56] The automatic trimming device 17 serves to automatically cut or trim the edge ends of the fiber sheets which are not ultrasonically welded. If the edge ends of the fiber sheets which are not ultrasonically welded are caught, they may act as a reason that tears the fiber sheets. In addition, repeated bending can readily weaken the edge ends, thereby allowing the infiltration of foreign materials. A cutter automatically cuts or trims unnecessary portions from the fiber sheets while the fiber sheets are passing through the cutter.

[57]

[58] Cc) Adjusting height of pattern roller according to thickness of overlaps of fiber sheets

[59] Step (c) is carried out to adjust pressing pressure according to the thickness of the fiber sheets. Since the degree of welding is varied according to the thickness of the fiber sheets, the pressing pressure is adjusted to ensure optimal welding regardless of the thickness of the fiber sheets. For this purpose, the fiber sheets pass through a height adjustment device 19.

[60] The height adjustment device 19 measures a pressure that the air compressor applies to the pattern roller against the fiber sheets regardless of the thickness and type of the fiber sheets, and then automatically adjusts the thickness of the fiber sheets so that the fiber sheets can be better welded by energy transmitted by an ultrasonic oscillator.

[61] The pressure of the air compressor applied is 3 to 4.5 bars in the case of thin fiber sheets, and 5 to 6.5 bars in the case of thick fiber sheets. The thickness of the fiber sheets to be used is generally about 0.5 to 20mm. The height that is optimal for ultrasonic welding can be varied according to welding rate, the type of material of the

fiber sheets and the quantity of energy created from the ultrasonic oscillator. In general, the height is preferably 0.5 to 10mm. However, it is not intended to limit the present invention.

[62] The height adjustment device 19 has a spring 199 mounted on a support of the pattern roller as shown in FIG. 5 so that the pattern roller can press the fiber sheets under a predetermined pressure. With the spring 199, the pattern roller can elastically rise or descend according to the thickness of the fiber sheets thereby adjusting its height.

[63]

[64] (d) Transmitting energy to pattern roller via ultrasonic generator to weld and bond overlaps of fiber sheets

[65] In step (d), energy generated by the ultrasonic generator 21 is transmitted to the pattern roller to weld and bond the fiber sheets. The ultrasonic generator 21 includes an ultrasonic oscillator 211, a booster 212 and a tool horn 213 as shown in FIG. 5.

[66] When the ultrasonic generator is supplied with electric power of AC 220V (50 to

60Hz), the ultrasonic generator transforms it into electric energy of 15 to 50KHz and transmits the transformed electric energy to the ultrasonic oscillator 211. Then, the ultrasonic oscillator 211 converts the electric energy into vibration energy and transmits the converted vibration energy to the booster 212 and the tool horn 213. At this time, ultrasonic energy instantaneously generates friction heat to a thermoplastic material with amplitude increase adjusted and pressing conducted, thereby enabling strong molecular bonding. The tool horn is shaped as a circular dish, and rotates at a predetermined speed to prevent the thermoplastic material from sticking to a disk part thereof. The rotating speed is proportional to the speed of an ultrasonic sewing machine.

[67] In the meantime, vibration frequency (vibration energy) transmitted as above migrates to the pattern roller 31 arranged above the horn 213. Since the ultrasonic generator 21 including the horn and the pattern roller 31 have different transmission ranges of vibration frequency due to respective material properties and mechanical characteristics, high vibration-induced friction heat takes place in contact areas of the ultrasonic generator and the pattern roller because of different moving ranges of vibration frequency. The vibration-induced friction heat, as a result, welds the fiber sheets placed between the ultrasonic generator and the pattern roller.

[68] The overlaps of the fiber sheets are welded as above and then, as shown in FIG. 5, bonded and formed by the pattern roller 31. The pattern roller 31 also has a protruding pattern 33, which can be formed in various shapes so that the fiber sheets can be designed into various patterns.

[69] The pattern C of the pattern roller 31 formed as shown in FIG. 6(a) allows upper

and lower portions of the welded portions are completely bonded without interruptions. The safety garments should provide continuously welded portions to ensure complete sealing so that chemical materials do not infiltrate through connecting portions of the fiber sheets. Those portions welded by the pattern roller maintain a sufficient degree of tensile strength while serving to prevent any infiltration of liquid or gaseous toxic materials.

[70] Accordingly, the pattern roller 31 may be carved with various designs of patterns according to usages. The pattern roller 31 moves on and presses the welded portions of the fiber sheets to bond the welded portions of the fiber sheets, thereby enhancing tensile strength. This can also achieve airtightness separately for the upper and lower portions of the welded portions, thereby blocking the infiltration of liquid or gaseous toxic materials.

[71] If the pattern D is interrupted as shown in FIG. 6(b), chemical materials may pass through interruptions of welded portions and thus an enough sealing function cannot be achieved.

[72] While the present invention has been described with reference to the particular illustrative embodiments and the accompanying drawings, it is not to be limited thereto but will be defined by the appended claims. It is to be appreciated that those skilled in the art can substitute, change or modify the embodiments into various forms without departing from the scope and spirit of the present invention.