| 摘要 |
A method for forming a strong and flexible bond between two plastic fabric layers requires the controlled use of an ultrasonic welding apparatus. Control of the time ultrasonic energy is delivered to the two overlapped plastic fabric layers, and of the pressure placed upon those layers during that time, is exercised to ensure that no melting of the yarns from which the two fabric layers are woven occurs. Rather, the yarns are softened by the application of ultrasonic energy, and are compressed together between the horn and an anvil to force them to adhere to one another. After the ultrasonic energy is turned off, compression is maintained while the overlapped plastic fabric layers cool and harden. A strong, flexible bond, suitable for operation as a seam for an endless belt, is obtained. Because the yarns do not melt during the application of the ultrasonic energy, the bond obtained by the practice of the invention is not brittle, and consequently is not susceptible to the cracking and breakage observed in the bonds produced by ultrasonic welding in the prior art.
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