摘要 |
A plastic heel is attached by inserting through an insole of a shoe a fastener, and vibrating the fastener at ultrasonic frequency to cause its shank to melt the plastic and become embedded in the heel. The fastener may be a staple with wide legs having holes therein. The shank of the shoe may be bridged by the staple for added attachment strength. Since less work penetration is needed than in nail-attaching of heels, advantage is gained especially in securing sharply tapering or so-called "stiletto" heels. |