Automatic knot-tying device

A mechanism for tying a flexible filament into a discrete knot around a workpiece, having a longitudinal axis, comprising:

• a housing, said housing defining a reference plane generally orthogonal to the longitudinal axis of the workpiece,
• a plurality of wrapping elements-mounted to the housing, each element being capable of circumscribing the workpiece in a plane generally coplanar with the reference plane by rotating around the workpiece, at least one of said wrapping elements defining a shuttle receptacle, and
• a plurality of hooks mounted to the housing, said hooks extending into the proximity of the workpiece and being capable of being spaced away from the workpiece generally in a plane generally coplanar with the reference plane, and
• at least one shuttle slidably mounted within the shuttle receptacle of at least one of the wrapping elements, said shuttle also including a clamp for clamping the lead end of the filament.

A method for automatically tying a flexible filament into a discrete knot by pulling the filament and thereby defining a filament path about a generally cylindrical workpiece having a longitudinal axis, using a device comprising a plurality of generally arcurate wrapping rings capable of circumscribing the workpiece, one such ring having a filament guide attached thereon for channeling the filament into the proximity of the workpiece, a shuttle slidably mounted to at least one of the wrapping rings, said shuttle comprising a cutting blade and a filament clamp, and a plurality of hooks, capable of extending into and out of said path of the filament in the proximity of the workpiece, such method comprising the steps of:

• positioning the wrapping rings around the workpiece,
• pulling the flexible filament through the filament guide and clamping it to the filament clamp of the shuttle,
• pulling the flexible filament generally transversely around the workpiece, while
• contemporaneously circumscribing the workpiece with the wrapping rings while the shuttle travels between the rings carrying the filament,
• contemporaneously extending the hooks into and out of the path of the pulled filament so as to interlace the flexible filament to form a knot, and
• subsequently cinching and securing the knot about the workpiece.