Patent Publication Number: US-6663678-B2

Title: Method and apparatus for treating tubular knit goods

Description:
PRIORITY CLAIM 
     This application is based on and claims the priority under 35 U.S.C. §119 of German Patent Application 100 65 171.2, filed on Dec. 23, 2000, the entire disclosure of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a method and an apparatus for treating tubular textile goods, and especially tubular knit goods containing a first portion of natural fibers and a second portion of synthetic elastomeric fibers. The treatment may involve, for example, steam treating, heating, relaxing, expanding, and/or heat fixing/setting of the goods. 
     BACKGROUND INFORMATION 
     German Patent Laying Open Publication 198 19 051 A1, and corresponding U.S. Pat. No. 6,016,591 (Strudel et al. ) disclose a method and an apparatus for treating tubular knit goods comprising a first portion of natural fibers and a second portion of synthetic elastomeric fibers. The entire disclosure of U.S. Pat. No. 6,016,591 is incorporated herein by reference, for general information, because the method and apparatus of the present application have similarities with respect to, and represent a further development of, the method and apparatus disclosed in U.S. Pat. No. 6,016,591. 
     In the known treatment process and apparatus according to U.S. Pat. No. 6,016,591, the tubular knit goods are transported and guided in such a manner that the goods pass along the circular internal spreader or expander arranged in the heat fixing chamber in an upward vertical direction, namely from the bottom to the top of the circular spreader in the heat fixing chamber. While the known method and apparatus according to U.S. Pat. No. 6,016,591 achieve many benefits and advantages in the treatment of the tubular knit goods, a certain disadvantage has also been discovered. Namely, due to the transport of the goods in the vertical upward direction over the circular expander in the heat fixing chamber, this gives rise to a longitudinal tension in the tubular goods, which remains and causes negative influences in the finished product, i.e. the finished treated goods. Particularly, this longitudinal tension is caused by the weight of the tubular goods, the acceleration forces of lifting the tubular goods in the upward transport, the friction of the tubular goods relative to the circumferential surface areas of the circular spreader and the pre-tension force between the fixing rollers of the circular spreader. 
     German Patent Laying-Open Publication 41 31 636 A1 further discloses a method and an apparatus for carrying out the hot air drying of a spread-out textile web, especially a sensitive or delicate textile web of knit or knitted goods. In the known method and apparatus, before being transported into the hot air drying zone, the knit goods in the form of a flat web are supplied with a leading advance and laid (especially in the form of folds) onto the feed end of an air-permeable carrier belt. Then the goods are transported through the drying zone on this carrier belt. The goods being transported or supplied with a “leading advance” means that a quantity of the goods is supplied in excess of or ahead of the demand of the goods being transported away by the carrier belt. The textile web can also be in the form of flat laid-out tubular goods. In order to be able to treat the spread-out flat web of goods using dry air, with an especially low tension of the goods, the known method and apparatus use at least one brush roller extending across the entire width of the flat web to form and lay uniform folds of the flat web onto the feed end of the carrier belt. 
     In order to subject tubular knit goods made of a first portion of natural fibers and a second portion of synthetic elastomeric fibers to a thermal fixing or heat fixing process, for technological reasons, the knit goods must be supplied to the treatment process in a form or condition other than a flat laid out form and other than a form in which the knit goods are laid out in uniform folds. Namely, such flat or folded forms of the knit goods are not suitable for uniformly carrying out the heat fixing treatment process on knit goods having natural fibers and synthetic elastomeric fibers. While the delivery of a flat web in loose uniform folds on a carrier belt may be suitable for simply heat drying the flat web of material in a low tension manner, it is not suitable for carrying out a heat fixing process, either of tubular goods or of a flat web of goods. For example, the heat fixing process requires the goods to be held and expanded in a controlled configuration with controlled expansion or tension at varying stages of the process. 
     SUMMARY OF THE INVENTION 
     In view of the above, it is an object of the invention to provide a method and an apparatus for treating tubular textile goods, and especially knit goods with a first proportion of natural fibers and a second proportion of synthetic elastomeric fibers, wherein the transport and guidance of the tubular goods over at least one circular expander or spreader is improved in such a manner so as to reduce the tension forces exerted on and in the goods. The invention further aims to avoid or overcome the disadvantages of the prior art, and to achieve additional advantages, as apparent from the present specification. 
     The above objects have been achieved according to the invention in a method for treating tubular textile goods, and especially knit goods with a proportion of natural fibers and a proportion of synthetic elastomeric fibers, in which the textile goods are subjected to a steam treatment process and thereafter a heat fixing process while the goods are in a circular expanded condition and being transported in a vertical direction, i.e. along a vertical axis. According to the invention, the goods are first accumulated to form a goods buffer of a loose excess quantity of the goods upstream of or before the heat fixing treatment, and the transport of the goods during the heat fixing treatment is in a vertically downward direction. 
     More particularly, a main treatment section of the circular spreader is arranged in the heat fixing chamber of a treatment apparatus while an inlet or feed section of the circular spreader is arranged vertically above the heat fixing chamber. The feed section has a substantially conical configuration, while the main section has a substantially cylindrical configuration which preferably has an adjustable diameter. In this context, the term “substantially” means that the configurations of the spreader sections are not truly conical or cylindrical with a truly circular cross-section, but rather the cross-sectional perimeter shape is made up, for example, of a plurality of straight segments, which may be rollers or the like. Thus, the perimeter may be an octagon, decagon, or other polygon rather than a true circle. 
     In the inventive method, the tubular goods are continuously fed or supplied at a first predetermined transport velocity to the feed section of the circular spreader above the heat fixing chamber whereby the tubular goods temporarily form a goods buffer or excess material reserve on the feed section. The tubular goods are then continuously transported out of the goods buffer on the feed section of the circular spreader at a predetermined second transport velocity, and transported further over the main body section of the circular spreader to be subjected to the heat fixing process in the heat fixing chamber. 
     The invention may especially include the following features. The tubular goods are first subjected to a steam treatment in a heating chamber, which itself may be per se conventional. The goods are deflected back and forth at least once in the heating chamber and are then delivered continuously at the first transport velocity to the cone-shaped feed section of the circular spreader. The supplied tubular goods form a tubular goods buffer or excess reserve of the tubular goods on the feed section of the circular spreader while temporarily relaxing and possibly shrinking. Next, the tubular goods are continuously transported out of the goods buffer or reserve on the feed section at a second transport velocity that is for example, less than the first transport velocity. Thereby, the tubular goods are transported in a circular expanded condition in a downward vertical direction from the top toward the bottom over the circular spreader while undergoing the heat fixing process. During this downward vertical transport of the tubular goods, the weight of the goods contributes to the downward transport and allows the tension in the goods to be reduced. 
     As an alternative, the first and second transport velocities can be equal to each other, as long as the first drive and therewith the supply of the tubular goods to the feed section of the circular spreader is operated with a leading advance relative to the second drive that further transports the tubular goods at the second transport velocity from the feed section over the rest of the circular spreader. This leading advance supply of the tubular goods to the feed section of the circular spreader means that an advance reserve quantity of the tubular goods is supplied ahead of or before the transport demand at which the goods are transported away at the second transport velocity. As a simple example, the supply of the goods to the feed section is started a short delay time before starting the transport of the goods away from the feed section, whereby the goods buffer is built up during that short delay time. 
     The inventive apparatus for carrying out the above method includes a preheating chamber with a steamer device, and downstream thereof a heat or thermal fixing chamber with a circular internal expander or spreader arranged therein. An inlet or feed section of the circular spreader including a spreader head is arranged at the top of or actually above the heat fixing chamber. Various feed rollers and deflection rollers are arranged to transport the goods in a downward vertical direction onto the inlet or feed section and then downwardly over the remainder of the circular spreader through the heat fixing chamber. In this specification, the terms “upstream” and “downstream” define relative positions with respect to the normal flow or travel direction of the goods along a goods travel path from the beginning to the end of the treatment process through the treatment apparatus. 
     The inventive method and apparatus achieve the following advantages. The vertically downward transport of the tubular goods, in the circular expanded condition over the circular spreader, from the top to the bottom thereof, beneficially uses the weight and gravitational acceleration of the tubular goods to contribute to the transport. Therefore, the amount of required transport power is reduced, and as a result, the electric motors driving the various drive rollers and the like have a reduced power requirement. Also, as a result of the beneficial gravitational influence, the longitudinal tension of the tubular goods is minimized, which in turn has a positive effect on achieving the desired fixed structure of the knit tubular goods. The formation of a goods buffer in the inlet feed section of the circular spreader gives the goods an opportunity to relax and possibly to shrink in length and width, at least during the time the goods are temporarily stored in this goods buffer or reserve, until the goods are transported out of the buffer at the second transport velocity into the heat fixing chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the invention may be clearly understood, it will now be described in connection with an example embodiment, with reference to the accompanying drawings, wherein: 
     FIG. 1 is a schematic sectioned or broken-open view of the internal arrangement of a treating apparatus, including a preheating chamber and a heat fixing chamber, for treating tubular knit goods according to the invention; and 
     FIG. 2 is a schematic view of the treating apparatus of FIG. 1, as seen along the plane II—II in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS AND OF THE BEST MODE OF THE INVENTION 
     Many aspects of the present inventive method and apparatus for treating tubular knit goods are the same or similar to such aspects described in U.S. Pat. No. 6,016,591 (Strudel et al.), the disclosure of which is incorporated herein by reference. Familiarity with that disclosure is assumed, and many of the detailed features that are common to the present invention and the prior patent will not be described again herein. 
     As shown in present FIG. 1, the tubular knit goods  1  are initially supplied in a supply stack  2  of the raw tubular knit goods in a flattened and folded configuration. The goods  1  are removed from this supply stack  2  in a generally known manner using at least one drawing-off roller  4  that is rotationally driven by at least one electric motor drive  3 . In the present illustrated example, the drawing-off roller  4  is located within a preheating chamber  5  of the treatment apparatus  6 , but various different locations are also possible. Before the goods  1  are transported into the preheating chamber  5 , the goods  1  are pulled in a flattened condition over two deflection rollers  7  and  8  located vertically above the goods supply stack  2 , and from there are transported to a generally known flat spreader device  9  which is arranged approximately below a goods inlet roller  11  of the preheating chamber  5 . From the flat spreader device  9 , the knit goods  1  are transported in the flat spread-out condition over at least one deflection roller  10  located downstream or after the flat spreader device  9 , and from the deflection roller  10  to the above mentioned goods inlet roller  11 , from which the goods  1  are pulled by the drawing-off roller  4  into the preheating chamber  5 . 
     A goods steamer  12  is arranged in the preheating chamber  5 . The goods  1  are transported from the drawing-off roller  4  over a deflection roller  13  arranged with its axis parallel to the drawing-off roller  4 , and from there vertically through the steamer arrangement  12 , vertically downward from its inlet to its outlet, in the pre-heating chamber  5 . After leaving the steamer arrangement  12 , the goods  1  are transported, in a generally known manner, over at least one floating compensating roller  14  and then over plural first deflection rollers  15  and plural second deflection rollers  16  that are all arranged with their axes parallel to each other, whereby the first deflection rollers  15  and the second deflection rollers  16  are vertically spaced apart from each other. Thereby, the goods  1  are transported in a zig-zag fashion back and forth successively between deflection rollers  15  and deflection rollers  16  through the preheating chamber  5 . 
     After leaving the last deflection roller  15  in the preheating chamber  5 , the goods  1  are transported further to at least one roller arrangement  18 ,  19  that is located vertically above the preheating chamber  5  and a heat fixing chamber  17  of the apparatus  6 . From the roller arrangement  18 ,  19 , the goods  1  are further supplied from the last roller of the arrangement  19  vertically downwardly via a spreader head  22  onto the conically configured inlet or feed section  20  of a circular internal expander or spreader  21 , of which the main body section  21 A is arranged within the heat fixing chamber  17 , and the feed section  20  is preferably arranged above the heat fixing chamber  17  in a buffer zone  30  of the apparatus  6 . The spreader head  22  includes an electric motor drive  22 B (see FIG. 2) which rotatingly drives the fixing roller  22 A of the spreader head  22 , so as to transport the goods  1  onto the inlet or feed section  20 . The drive speed of the electric motor drive  22 B is controllable via an electronic controller  35 , so as to control the transport velocity of the goods  1  onto the feed section  20  of the circular spreader  21 . 
     According to a particular embodiment of the inventive method, the goods  1  are transported by means of the drive  22 B onto the feed section  20  of the circular spreader  21  at a predetermined first transport velocity, which is greater than the second transport velocity that is necessary for fixing the goods as the goods are transported over the main body section  21 A of the circular spreader  21  in the heat fixing chamber  17 . Thereby, it is possible to form or build-up a goods buffer  1 A or excess reserve  1 A on the feed section  20  of the circular spreader  21 . This goods buffer  1 A comprises an excess slack amount of the goods  1 , which are loosely folded or slumped onto the conical feed section  20 , as represented by the wavy or undulating line of the goods  1  forming the goods buffer  1 A as shown in FIGS. 1 and 2. This loose excess amount of the goods  1  forming the goods buffer  1 A allows the goods in the buffer  1 A temporarily to relax and possibly also to shrink in width and length. 
     From there, the goods  1  are further transported by a second electric motor drive  23  which drives at take-off roller arrangement  23 A at the bottom of the circular spreader  21 , by means of which the goods  1  are pulled in a vertically downward direction  24  from the goods buffer  1 A on the feed section  20 , over the remaining body section  21 A of the circular spreader  21 , downwardly through the heat fixing chamber  17 , at a second transport velocity that is less than or slower than the first transport velocity. The second transport velocity established by the second drive  23  is also controllable by the electronic controller  35 , based on operator inputs of desired transport velocities or selection of pre-programmed operating modes or combinations of the first and second transport velocities and operating sequences. The controller  35  is connected for control signal transmission, e.g. via electrical conductors, to any drive which is to be controlled thereby. 
     The above mentioned difference between the first and second transport velocities would result in an ever-increasing excess quantity of the goods  1  accumulating in the goods buffer  1 A during the operation of the method. If such an effect is to be avoided, it is alternatively possible to control the electric motor drives  22 B and/or  23  via the controller  35  so that the first transport velocity is equal to the second transport velocity, either from the time of initially starting the process, or only after a sufficient goods buffer  1 A has been built up. If the two transport velocities of the drives  22 B and  23  are to be equal right from the beginning of the process, it will be necessary to operate the first drive  22 B for a short time before starting the second drive  23 , so as to supply the goods  1  with a leading advance relative to the take-off of the goods by the second drive  23 , so as to thereby build-up the required goods buffer  1 A before starting the second drive  23 . 
     While being transported over the circular spreader  21  through the heat fixing chamber  17 , the goods  1  will be thermally fixed in diameter and fiber structure. This is achieved by holding the goods  1  in a particular expanded condition while subjecting the goods to an appropriate temperature for heat-setting the existing expanded condition of the fibers of the goods. For this purpose, the heat fixing chamber is tempered as needed, e.g. insulated and/or temperature/controlled. Then, after leaving the circular spreader  21 , the fixed goods  1  will be flattened from the circular expanded condition to a flattened condition, which is then transported over suitable deflection rollers to a roller  26  that is rotationally driven by an electric motor drive  25  and integrated into a folder device  28 , which folds the flattened fixed goods  1  back and forth to form an output or delivery stack  27  of the treated goods. 
     Although the invention has been described with reference to specific example embodiments, it will be appreciated that it is intended to cover all modifications and equivalents within the scope of the appended claims. It should also be understood that the present disclosure includes all possible combinations of any individual features recited in any of the appended claims.