Textiles: spinning – twisting – and twining – Apparatus and processes – Elements
Reexamination Certificate
2001-01-05
2002-03-26
Worrell, Danny (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Elements
Reexamination Certificate
active
06360520
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a spinning ring for textile yarn spinning and more specifically relates to a spinning ring having a low friction, high durability bearing surface for supporting a traveler.
BACKGROUND OF THE INVENTION
In conventional spinning and twisting operations, spinning or twisting rings are used to support a traveler that moves rapidly around the circumference of the spinning ring. The traveler engages and guides a loose yarn as it is being twisted and wound onto a twisting spindle.
An increase in spinning speed increases the rate at which the traveler rotates around the surface of the spinning ring thereby also increasing the centrifugal force applied between the traveler and the ring. In turn, the greater centrifugal force increases frictional heating of the traveler and the spinning ring while also increasing the abrasive force applied to the traveler and to the spinning ring. Accordingly, spinning speed increases can cause burn-off and/or shortening of the lifetime of the traveler, and also typically decrease the lifetime of the spinning ring because the bearing surface of the ring can spall, chip, or otherwise become roughened.
As spinning speeds are increased the resulting increase in frictional or abrasive forces between the traveler and spinning ring can cause breaks in the yarn being spun or twisted. Yam breaks are particularly undesirable because they lead to downtime in the spinning operation and, thus, a lower manufacturing efficiency. In general, for a given spinning ring and traveler combination, there exists a practical spinning speed limit that cannot be exceeded without frequent breakage of yams. For this reason, the choice of traveler and spinning rings (i.e. the construction of the traveler and spinning rings) can have a substantial impact on manufacturing efficiency.
Spinning ring durability also impacts substantially on manufacturing efficiencies and/or costs. In particular, degradation of the bearing surface of the spinning ring by spalling, chipping or the like, is normally a gradual process. As the bearing surface of the spinning ring degrades, the frictional characteristics of the bearing surface increase. Although in some cases the initial degradation of the spinning ring surface can be addressed by decreasing spinning speeds and/or by selecting travelers of different weight or construction, the manufacturing non-uniformities and potential disruptions associated with changes in the frictional characteristics of the ring surface are costly in many cases and undesirable in any event. Accordingly, the bearing surface of the spinning ring should preferably exhibit uniform frictional characteristics over a substantial period of time, even when the spinning operation is conducted at extremely high speeds.
Attempts to simultaneously address spinning ring surface durability characteristics while also achieving sufficiently low frictional characteristics to allow high spinning speeds have met with only limited success until recent times, due, at least in part, to the contradictory objectives associated with high durability surfaces, and those associated with low friction surfaces. Specifically, high durability surfaces that are resistant to abrasive force typically possess an inherent hardness sufficient to apply significant abrasive forces to a traveler. However, if surface hardness of the ring is decreased in order to decrease the abrasive characteristics of the surface, the durability of the ring surface generally also suffers.
In this regard the textile industry has recently developed spinning rings having ceramic coatings and co-deposited metal/abrasion resistant materials on the bearing surface thereof, to impart superior hardness and superior durability. However, in practice, these spinning rings generally require a substantial break-in period. During the break-in period, the spinning equipment is operated at a relatively low spinning speed because the surface of the spinning ring is initially too rough to allow operation at high speed. The low speed spinning operation allows the initially rough surface of the spinning ring to be conditioned by contact with a moving traveler. Such break-in periods can last for time periods of one month or longer, thus substantially decreasing manufacturing efficiencies.
More recently, spinning rings have been provided that are capable of high-speed operations over a period of several years. These rings have a bearing surface comprising an electrodeposited coating of hard, nodular chromium, and are described in U.S. Pat. No. 5,829,240, entitled “Spinning Ring Having Improved Traveler Bearing Surface” issued Nov. 3, 1998, in the name of inventors Rio H. Benson and Gereon E. Poquette and assigned to A. B. Carter, Incorporated, the assignee of the present invention. In most cases, when these rings are treated in a polishing operation prior to use, only a relatively shortly break-in period is required prior to use of these rings in extremely high speed spinning operations. Nevertheless, in the case of fine yarns, break-in times of 1-2 weeks can be required in order to sufficiently condition the surface of the ring for use in high speed operations due to the relatively low weight travelers used in spinning fine yarns. The lighter travelers apply less conditioning force to the surface of the spinning rings and the lighter travelers are also more susceptible to damage with the result that the break-in period is longer and more travelers are used during the break-in period.
Although various conventional spinning rings can minimize or even eliminate break-in time for fine yarn spinning operations, these rings typically suffer from the undesirably low durability properties associated with spinning rings of conventional construction. For example, spinning rings described in U.S. Pat. No. 5,086,615, entitled “Coated Spinning Rings and Travelers”, issued in the name of inventor Bodnar, on Feb. 11, 1992, that have a surface coating with a particulate polymeric fluorocarbon dispersed in a metallic matrix, can have a very short break-in time requirement, but also typically have a useful life of less than about one year.
As detailed above, the textile industry desires a spinning ring that can impart increased durability and spinning speed over prolonged use periods without increasing the inefficient break-in period required to operate the device at standard productivity spinning speeds. To date, the successful modifications that have been used in conjunction with the spinning ring to improve durability and useful spinning speed have been hampered by typically requiring costly and sophisticated coating processes, modifications to the travelers used with the spinning rings and/or increased periods of break-in.
SUMMARY OF THE INVENTION
The present invention provides spinning rings having a traveler bearing surface that can be used at high productivity spinning speeds without spalling or cracking of the bearing surface of the spinning ring. The spinning rings of the present invention can be used in the as-manufactured state for high speed spinning of fine yarns; that is, no break-in period is required in order to achieve high speed spinning of fine yarns. Nevertheless, the spinning rings of the present invention have a hard and durable traveler bearing surface such that the rings can be used for high speed spinning without substantial degradation of the frictional characteristics of the traveler bearing surface of the spinning rings for periods of greater than about one year, typically longer.
The spinning rings of the present invention comprise an electroplated, hard amorphous chromium coating having a thickness of between about 0.05 mil (0.00005 in.) and about 1.5 mil (0.0015 in.), preferably between about 0.2 mil (0.0002 in.) and about 0.4 (0.0004 in.). The chromium plating can be applied to spinning rings formed from conventional base metals such as carbon steels and steel alloys. The frictional characteristics of the traveler bearing surface of the spinning ring are such that the ring can b
Faris Joe D.
Floder Jason P.
Poquette Gereon E.
AB Carter, Inc.
Alston & Bird LLP
Worrell Danny
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