The attachment of a strand of cord, thread, wire or other material to one or more pieces of material presents challenges to today's high speed manufacturing processes. As an example, consider the tampon industry. The rate at which the product is consumed requires that a high speed manufacturing process be employed. Current tampon designs employ a withdrawal string, usually a cotton cord, to allow the user to remove the product after use. The cord must be firmly attached to the tampon pad, and must not shear the product or leave material behind upon withdrawal.
One current method for attaching a cord to a pad involves sewing the cord to the pad, although this technique has a variety of disadvantages. The piercing of a cord by the thread actually weakens the cord, thereby requiring a thicker cord to meet any strength specifications. The use of thread to attach a cord to a pad introduces the possibility of thread breakage or jamming of the sewing apparatus. Current high speed industrial sewing machines operate at rates that are typically insufficient to feed a subsequent high speed production line. As a result, multiple sewing stations are required and their respective outputs must be merged to feed a single production line. Such multiple stations operating near their maximum rated speed, as well as the merging mechanism, increase possibility and frequency of mechanical failures, jams, etc. Further, the reciprocating motion of traditional sewing machine movement, combined with the very thin and flexible handling qualities of thread, further increase the likelihood of jams, or mechanical failure.
Another method of attaching a cord to a pad involves punching of a cord once through the pad, and entanglement of the cord about the pad, i.e. with a knot or other restraining mechanism. Punching a cord once through a pad suffers from a lack of redundancy of attachment. Should the cord fail to puncture the pad, the needle fail to feed the cord properly, or the pad mis-aligned, the cord will not be attached to the pad. Also, the force on the cord during the use of the product assembly is undesirably concentrated at the single point where the cord is attached to the pad.
Cord entanglement does not offer the mechanical strength or integrity offered by a cord that is firmly attached to the pad since the cord can slip off. Simply tying a string to a pad in such a fashion creates a product which is prone to failure.
Accordingly, a need exists for a cord attachment mechanism that is fast enough to support a subsequent high speed production line and which meets the reliability requirements of its users.