Saw-tooth clothings are used in different areas of processing textile fibers. In most cases, the saw-tooth clothings are mounted in the form of wires onto rollers. In a typical fiber-preparing process, the fibers are treated on so-called carders or carding machines as a preparation for the production of yarn or nonwoven fabrics. The fibers are fed via a feeding device to a drum, which is typically a roller provided with a hook- or saw-tooth clothing on its surface shell. The drum clothing together with the carding elements distributed over the circumference effects an alignment and a cleaning of the fed fibers. Depending on the product and the application, different elements arranged around the drum are used. The elements are configured as flats, cleaning elements, or rollers and can also be provided with a saw-tooth clothing. Subsequent to this treatment, the fibers are taken over by a doffer roller and removed from the drum clothing. In doing so, the clothing of the doffer roller engages in the fibers held by the clothing of the drum and detaches them from the drum. From the doffer roller, in turn, the fibers are transferred to a further roller and fed to a nonwoven fabric- or sliver-forming unit. Such takeover and transfer processes from one roller to another one can also be found at worker rollers of a carding machine.
From the prior art, different embodiments of saw-tooth clothings are known. For example, DE 100 12 561 discloses a saw-tooth clothing with a wave-shaped tooth back. This shaping of the tooth back is intended to prevent a premature detachment of the fibers from the saw-tooth clothing. The provided convex projection on the tooth back is intended to prevent the fibers from sliding off. A disadvantage of the disclosed clothing is that the shape of the tooth back prevents an early detachment only during a fiber takeover, but during the transfer of the fibers by the clothing, it does not provide any protection to prevent the fibers from sliding off. Based on this problem, DE 100 12 561 discloses an extremely pointed tip of the tooth in a further embodiment. However, in the course of use of the clothing, such a tooth tip gets lost due to wear.
Furthermore, EP 1 153 162 discloses a saw-tooth clothing, the teeth of which have an undercut edge on the tooth front. Said undercut edge is formed by a recess which points from the tooth front toward the back of the tooth. The disclosed tooth form is intended to increase the fiber retention during carding. The disadvantage of the disclosed clothing is that the form of the teeth represents a one-sided structure which is designed for firmly holding the fibers.
USPTO Backgrounds
USPTO Backgrounds