Needle-based apparatus for individualizing fibers and other textile entities for testing purposes

Abstract: Disclosed are various needle-based devices for individualizing single fibers and other entities from a fibrous mass, particularly for testing purposes. In one embodiment, an accelerated pin drafting machine has a plurality of combing elements which sequentially pierce a fiber mat and move within a drafting zone with increasing distance between adjacent combing elements. The accelerated pin drafting machine in turn feeds a fiber individualizer. In another embodiment, a comb-like needle sampler is provided which moves past a perforated plate such that portions of fibrous material protruding through the perforations are loaded onto the needle sampler. An elastomer clamping feedroll moves against the needles to clamp the sample, and then rotates to gradually feed fibers from the sampler. As an alternative to the elastomer clamping feedroll, a clamping block presses against the needles, and the needles are slowly retracted to gradually release fibers. In a third embodiment, fibers protruding through a perforated plate are loaded onto a single needle, and the ends of the fibers are drawn into an airstream moving through a passage defined by a housing on either side of a fiber plate. The fiber plate subsequently engages the needle to clamp fibers in position and the housing retracts to expose the fiber plate for fiber preparation. Thereafter, a roll or apron feeds individual fibers from the fiber plate.

Description: FIELD OF THE INVENTION The present invention relates generally to the testing of fiber samples and, more particularly, to needle-based apparatus for individualizing single fibers and other entities in textile fiber samples for testing purposes with a minimum of damage to the fibers, such as breakage. BACKGROUND OF THE INVENTION Testing of fiber samples, such as, but not limited to, cotton, is important for determining the market value of a particular batch of material, as well as for determining a suitable usage and what processing may be required in gins or spinning mills. Today, nearly 100% of the cotton grown in the United States is classed employing testing instruments. Testing includes determining such characteristics as fiber length, as well as the content of undesired textile entities such as trash and neps. As a relatively early example, a comb-like device for preparing a sample of ginned cotton for measuring the fiber length thereof is disclosed in Hertel Pat. No. 2,404,708, which issued in 1946. That same inventor later developed what is now known as a Hertel needle sampler, disclosed in Hertel Pat. US-A-3,057,019 which represents the closest prior art. The Hertel needle sampler is a comb-like device arranged for movement past a perforated plate which has a fibrous mass pushed against the opposite side so that portions of the fibrous mass protrude through the perforations and are loaded onto the needles. A screw-thread based locking device then retains the fibers on the needle sampler, forming what is known in the art as a tapered beard because the fibers are of varying lengths. The tapered beard is prepared by combing and brushing to parallelize the fibers, as well as to remove loose fibers. An automated version of the Hertel needle sampler is contained within and is a major element of fiber testing apparatus, known as the Model 900A High Volume Instrument (HVI). This apparatus has been manufactured by Spinlab, Inc., and is now manufactured by Zellweger Uster, Inc. in Knoxville, Tennessee. The tapered beard is then subjected to analysis. For example, an instrument known as a Fibrograph, formerly manufactured by Spinlab, Inc., and now by Zellweger Uster, Inc. in Knoxville, Tennessee, is employed to optically determine various characteristics of the tapered beard, including the profile along its length. In addition, a separate test may be made of the strength of the tapered beard. In some respects, the sample as taken by a Hertel needle sampler and the measurement of length and strength therefrom, are worldwide standards. The approach just described involves collectively testing, essentially simultaneously, all of the fibers of a sample, assumed to be a representative sample. An alternative approach is to individualize and test single fibers and other textile entities, for example neps and trash. Testing single fiber entities can provide a better analysis. Thus, measuring directly, and at high speed, physical properties of single entities in a fiber sample results in basic measurements which provide more and better information which is needed in modern textile manufacturing. The measurements are more basic because single entities (single fibers, single neps, single trash particles, single microdust particles, etc.) are directly measured rather than indirectly by measuring bulk or bundle properties. Equally importantly, they are more basic because statistical distributions are easily formed with the aid of modern electronics technology. However, such an approach requires means for individualizing single entities and feeding them one at a time into suitable analysis means for testing. Unfortunately such Hertel device according to US 3,057,019 does not permit gradual release of fibres. A device for such isolation is generally termed a "fiber individualizer", and is generally so termed herein, although a more precise term is "entity individualizer" since, for purposes of testing, it is necessary to accurately determine the amount of neps and trash in a particular sample, in addition to characteristics of the fibers themselves. An example of such single entity testing apparatus is disclosed in Shofner Pat. No. 4,512,060, which discloses what is termed in that' patent a microdust and trash machine (MTM), and what has since become known as an advanced fiber information system (AFIS), currently manufactured by Zellweger Uster, Inc. in Knoxville, Tennessee. In one form, the AFIS machine separates fibers and neps into one airstream, and trash into another air stream. Optical-based sensors then measure the individual entities. Individual entities can be analyzed at rates as high as 1000 per second. An AFIS more particularly includes an aeromechanical separator or fiber individualizer; high speed single entity sensors; and a high information rate computer for data collection and analysis. Improvements to the AFIS, particularly improved sensors where a single sensor analyzes neps, trash and fibers individualized all in one air stream are disclosed in Shofner et al Application WO91/14169 entitled "Electro-Optical Methods and Apparatus for High Speed, Multivariant Measurement of Individual Entities in Fiber or Other Samples", and in Shofner et al US Patent No. 5,321,496 entitled "Apparatus for Monitoring Trash in a Fiber Sample", and Application No. WO94/09355, entitled "Apparatus and Method for Testing Multiple Characteristics of Single Textile Sample with Automatic Feed." Individualized fibers may be however tested in a number of other ways, and the fiber individualizers of the present invention are not limited to any particular testing technique. For example, individualized fibers may simply be spread out on a horizontal surface which comprises a contrasting background, and optically imaged. The fiber individualizer portion of an AFIS, such as is disclosed in Pat. US-A-4,512,060, includes a cylindrical rotating beater wheel having projections which engage fibers of fibrous material fed to the beater wheel for testing. The beater wheels rotates at typically 7,500 rpm, with a circumferential velocity of 5,000 FPM, and is similar to the licker-in of a conventional carding machine, or the beater stage of an open-end spinning head, with the exception that the AFIS beater wheel includes perforations which allow radially inward airflow. One disadvantage of the fiber individualizer disclosed in Pat. No. 4,512,060 is that fibers are subject to breakage as they are fed from a fibrous mass and abruptly engaged by the pins of the rotating beater wheel. In particular, fiber damage is caused by the interaction of fiber held between a feed plate/feed roll arrangement and the pinned cylinder rotating at high speed. The resultant action does liberate single fibers from the sample fiber mass but it also causes fiber breakage, and breaks up some foreign matter in the fiber (i.e. cotton trash). This action of restraining a portion of the fiber while quickly accelerating another portion of the fiber is well represented in mill processes (especially in opening, cleaning and carding), and leads to similar problems. Further damage results as fibers, in relatively random orientations, are carried past card flats. The damage is, in general, more pronounced in a sample containing randomly oriented, highly entangled fibers (bale stock or card mat) than it is in a sample containing disentangled, parallel oriented fibers (sliver). Thus, it has been observed that, when parallelized fibers, such as sliver, are fed to the rotating beater wheel of an AFIS, far less fiber breakage occurs. However, bulk fiber for testing is generally not available in parallelized form. Another disadvantage of the AFIS Fiber Individualizer is that it requires an elongated, sliver-like sample. For testing fibrous masses, wherein the fibers are randomly oriented, this elongated sample must be currently hand-formed. It follows that alternative means for collecting representative samples and introducing them into AFIS is needed. This need is rapidly increasing now, as automation requirements increase. Several processes are known for parallelizing fibers, and an important one of such process is known as drafting or drawing, which particularly is employed in production environments, not in testing environments and not for randomly oriented fibrous masses. Other forms of drafting are known, such as apron drafting or Casablanca drafting wherein a web of fibers, already parallelized and partially drafted, is transported between a pair of belt-like moving aprons and then through a pair of rollers turning at a higher speed. In some situations, such as is disclosed in U.K. Pat. No. 1,242,171, fibers are released from the roller pair essentially one at a time into an airstream. SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provide improved apparatus for individualizing fibers and other entities, such as trash and neps, from a sample of bulk fiber material, for testing purposes. It is another object of the invention to provide an improved apparatus which, at least, receives a mass of entangled, disoriented fibers and produces, at an output, a flow of substantially disentangled, parallel oriented and undamaged fibers, particularly for delivering to an AFIS. In accordance with the invention, the needle-based apparatus for individualizing single fibers and other entities from a loose mass is based on the Hertel needle sampler referred to hereinabove, but includes means for feeding fibers and other entities from the needle sampler for individual analysis, in contrast to analyzing a tapered beard. In particular, such apparatus includes a sample holder with a plate having perforations and a sample side against which a loose mass of fibrous material is pressed such that portions of the fibrous material project through the perforations, and a comb-like needle sampler having a plurality of needle elements in a row and arranged for generally parallel movement relative to the plate on the other side of the plate so as to load fibers from the projecting portions onto the needle sampler. The apparatus is characterized by an element arranged to selectively engage the needle elements along at least a portion of their lengths for clamping loaded fibers on the needle sampler and for permitting subsequent gradual release of fibers from the needle sampler. In one form, this element takes the form of an elastomer clamping feedroll which moves against the needle elements for clamping loaded fibers, and subsequently rotates to gradually feed fibers from the needle elements. Alternatively, a clamping block may be provided which moves relative to a needle element against the needle elements for clamping loaded fibers, and the needle elements subsequently retract to gradually release fibers. In one embodiment based on the Hertel needle sampler, the apparatus includes a cylindrical rotating beater wheel, such as the input stage of an AFIS, having projections for engaging fibers as they are released from the needle sampler. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 depicts the loading of a needle sampler in accordance with a second embodiment of the invention; FIG. 2 is a front view of the needle sampler of FIG. 1; FIG. 3A is an enlarged front view of a needle holder; FIG. 3B is an enlarged side view of the needle holder; FIG. 4 is an enlarged view of the elastomer clamping feedroll of FIG. 1 ; FIG. 5 depicts an alternative to the elastomer clamping feedroll in the form of a retracting pin; FIG. 6 depicts the needle sampler of FIG. 1 feeding an AFIS machine; FIG. 7 is an enlarged view depicting the feeding of material into an AFIS; FIGS. 8 and 9 are alternative forms of the needle sampler based on a modified "bucket" sampler; Referring now to FIGS. 1-9, depicted is another embodiment of needle-based apparatus in accordance with the invention. The apparatus of FIGS. 1-9 is based on a Hertel needle sampler, such as is disclosed in the above-identified US-A-3,057,019. An important aspect of the Hertel sampler is passing a comb-like needle sampler past perforations in a metal plate through which the fibrous mass is pressed such that fibers of varying lengths are loaded onto the pins, and subsequently locked. In the traditional use of the Hertel sampler, the resultant tapered beard is combed, brushed and measured, all as described hereinabove. In accordance with the present invention, the fibrous material is sampled in the same way, and it has been shown that this particular sampling technique generally produces a representative sample. The present invention differs from the traditional Hertel sampler in that fibers are individually fed from the sampler for subsequent analysis. FIG. 1 illustrates a sample holder 150, including a plate 152 having perforations 154, and a sample side 156 against which a loose mass 158 of fibrous material is pressed by a pressure plate 160. Portions 162 of the sample 158 thus project through the perforations 154. The perforations 154 are in the order of 16 mm (0.63 inch) in diameter, with a spacing of 22 mm (0.88 inch). As may be seen in FIG. 1, the edges of the perforations 154 are rounded and smooth so as to minimize cutting and breakage of fibers as fibers are pulled through the perforations 154. The apparatus additionally includes a comb-like needle sampler 164, shown also in FIG. 2 in front view. The needle sampler 164 includes a plurality of individual pins or needle elements 165. Traditionally, the needle elements 165 are spaced by 2 mm (1/13 inch), and are about 0,5 mm (0.02 inches) in diameter. Their projected length above their mount is approximately 0.5 mm (0.2 inches), and the overall width of the sampler in the FIG. 2 orientation is in the order of three inches. FIGS. 3A and 3B are enlarged views of the needle holder portion of the needle sampler 164. The needle sampler 164 is arranged for generally parallel movement relative to the plate 152 so as to load fibers from the projecting portions 162 onto the individual needle elements or pins 165, to produce the results shown in FIG. 2. The protruding fibers are however first engaged by a guide plate 157 which facilitates control of the amount of sample collected. FIG. 2 in particular illustrates what is known in the art as a tapered beard 166 which, after combing and brushing described hereinbelow, comprises a plurality of fibers of varying lengths loaded onto the pins or needle elements 165 at various intermediate points along the length of the individual fibers. In the traditional Hertel sampler, the tapered beard 166 remains locked in position for the remainder of the operation. Instead of the threaded locking and unlocking device of the Hertel sampler, the present invention employs an element, shown in FIG. 1 as an elastomer clamping feedroll 170, which is arranged to move forward or close and thereby to selectively engage the needle elements along at least a portion of their lengths for locking loaded fibers on the needle sampler 164. The feedroll 170 is seen in the open or sampling position in FIG. 1 and in the closed position in FIG. 4. Guide 157 can move together with feedroll 170 but this is not essential. FIG. 4 is an enlarged view of the elastomer clamping feedroll, while in closed position to engage the needle elements 165, to clamp the fibers 166 in place. As indicated at 172, the elastomer clamping feedroll 170 is deformed to hold fibers against the needles along a portion of the length of the needles, rather than at a single pinch point. As indicated by the respective arrows 174 and 176, the elastomer clamping feedroll 170 is capable of both a translation motion (arrow 174) to permit clamping, and a rotation motion (arrow 176) for subsequent gentle rolling off of the fibers from the needle sampler. A suitable mounting and drive arrangement (not shown) is provided to accomplish these two motions. As an alternative to the row needle sampler 164 with elastomer feedroll 170, depicted in FIG. 5 is a retractable pin embodiment 171. In FIG. 5, a row of pins 180 is arranged like the needle sampler 164 (FIG. 2) and may, for example, also be made of stainless steel. A mounting block 182 is provided in which the needle elements 180 move downwardly, after loading, for feeding into further processing stages. The downward (and upward) movement is enabled by drive means 186. After loading but prior to moving to further processing steps, the fibers 166 are clamped against the needle elements 180 by internal elastomer bar 187. Clamping bar 187 is driven by actuator rod 189 and in machined guide-ways 191. For subsequently slowly feeding individual fibers one at a time from the needle elements 180, after loading and clamping, the needle elements 180 may be retracted through movement of the needle holder 186 and needle element 180 in a downward direction, as viewed in the FIG. 5 orientation, whereby fibers are individually released. The arrangement of FIG. 5 thus provides for two different types of movement, one for clamping, and one for feeding. FIGS. 6 and 7 illustrate the needle sampler of FIGS. 1-4, including the elastomer clamping feedroll 170, employed to feed fibers into an AFIS. FIG. 7 will be recognized as another form of the AFIS Fiber Individualizer. In this case the individualized coarse 195 and fine 196 trash separations are recombined with the individualized fibers, neps, etc. The objectives of feeding AFIS Fiber Individualizers and with the row needle sampler 164 or 171 are to reduce fiber damage and/or to facilitate automation. Methods and apparatus enabling the latter objective are disclosed in EP-A-0 606 626 entitled "Acquisition, Measurement and Control of Thin Webs of In-Process Textile Materials". FIG. 8 depicts a modification of a Hertel needle sampler, as embodied in a Model 900A High Volume Instrument (HVI), manufactured by Zellweger Uster, Inc., Knoxville, Tennessee. More particularly, the sampling drum 200 and operational steps are modified in accordance with the invention to achieve fiber individualization and automation. The apparatus of FIG. 8 includes a known apparatus 200 in the general form of a cylindrical drum which is rotatable about its axis, and which is at least partially hollow for receiving a sample. The drum is approximately 0,3 m (twelve inches) in diameter and 0,14 m (5.5 inches) in width and rotates within a housing 213. The drum 200 includes a sample holder portion 202 including a circumferential cylindrical wall segment 204 with perforations 206 against which a loose mass of fibrous material 208 to be sampled is pressed from the inside, such that portions of the fibrous material 208 project through the perforations 206. A plate 210 pivotally mounted at 212 provides pressure on the sample 208. The drum 200 additionally includes a card doffer wire portion 215 including a circumferential segment having doffer wire 216 projecting radially outwardly. Also provided is a comb-like needle sampler 164, substantially like the needle sampler 164 of FIG. 1, positioned adjacent to the drum 200 such that fibers projecting through the perforations 206 are loaded onto the needle sampler 164 as the cylindrical wall segment of the sample holder rotates in a first clockwise direction past the needle sampler. In the operation of the drum 200 as thus far described, the drum is initially rotationally oriented with the sample opening 231 adjacent reference mark 230A. That is, points 230A and 230B are in juxtaposition. The cover 233 is hinged at 237 and is opened in the direction of the arrow 235 and a sample 208 is placed within the sample holder. The cover 233 is then closed and the drum 200 is rotated in a clockwise direction such that the perforations 206 move past the needle sampler, loading fiber onto the needles, in the same manner as depicted hereinabove with reference to FIG. 1. After loading, the elastomer clamping feedroll 270 is then moved against the needles, in the position illustrated, to clamp the sample. At this stage, point 232 on the bucket 200 is positioned near the needle sampler 220 or reference mark 230. The remaining operation differs substantially from the conventional Hertel sampler as embodied, for example, in the model 900A drum. In particular, in the model 900A drum as conventionally employed, as the drum continues to rotate, the card doffer wire 216 combs the tapered beard which is locked onto the needle sampler. This combing action has the effect of removing loose fibers and trash from the tapered beard such that a tapered beard of initially 0.5 gram, for example, is reduced to about 0.1 to 0.2 gram. In the conventional device, the tapered beard is then removed for further Fibrograph testing as described hereinabove in the "Background" section. In accordance with the present invention, rather than holding the tapered beard for combing, as the bucket 200 continues to rotate clockwise, carrying the doffer wire past the needle sampler, the elastomer clamping feedroll 270 rotates in a clockwise direction as indicated to slowly feed all of the fiber from the needle sampler onto the doffer wire. Ideally, 100% of the collected fiber sample is deposited uniformly on the doffer wire 216, and preferably this is a heavier sample, for example, 1.0 gram. At this point, the needle sampler 164 is retracted and drum 202 is rotated in the counterclockwise direction, and fiber on the doffer wire is fed to the cylindrical rotating beater wheel of an AFIS machine 240, for individualizing and testing as already described hereinabove. The needle sampler 164 and 171 can thus advantageously feed textile entity samples to an AFIS system in FIGS. 6 or 7 or can feed the HVI 900A drum of FIG. 8 which in turn feeds and AFIS system. It will be appreciated that the needle sampler 164, in combination with the uniform loading into and combing and individualization action by the doffer wire 216 can also directly feed an AFIS sensor as depicted in FIG. 17. In FIG. 9, a rotary brush 250 individually removes the entities from doffer wire 216. The entities are collected by an air flow and then transported to AFIS sensor for measurement. Brush 250 has backward inclined bristles 252 which are about 19 mm (0.75 inches) long and made preferably of nylon. Brush 250 diameter is about 6 inches and rotational speed is about 3000 RPM. Brush 251 moves within housing 254. The 900A drum 200 and brush 250 are sealed except at 260, where the airflow 262 enters in response to the AFIS sensor airflow.

Claims: Needle-based apparatus for individualizing single fibres (166) and other entities from a loose mass, comprising a sample holder (150) including a plate (152) having perforations (154) and a sample side (156) against which a loose mass (158) of fibrous material is pressed such that portions of the fibrous material project through said perforations, a comb-like needle sampler (164) having a plurality of needle elements (165, 180) in a row and arranged for generally parallel movement relative to said plate on the other side of said plate so as to load fibres from the projecting portions onto said needle sampler, characterized by an element (170, 178) arranged to selectively engage said needle elements (165, 180) along at least a portion of their length for clamping loaded fibres (166) onto said needle sampler and for permitting subsequent gradual release of fibres from said needle sampler. Apparatus according to claim 1, characterized by said element comprising an elastomer clamping feedroll (170) which moves against said needle elements (165) and subsequently rotates to gradually feed fibres (166) from said needle elements. Apparatus according to claim 1, characterized by said element comprising a clamping block (187) which moves relative to said needle elements (180) against said needle elements for damping loaded fibres (166), and wherein said needle elements subsequently retract to gradually release fibres. Apparatus according to claim 3, characterised by flexible needle elements. Apparatus according to claim 1, characterised by a cylindrical rotating beater wheel having projections for engaging fibres as they are released from said needle sampler. Apparatus according to claim 5, characterised by an elastomer clamping feedroll (170) which moves against said needle elements for clamping loaded fibres and subsequently rotates to feed fibres from said needle elements onto said rotating beater wheel. Apparatus according to claim 5, characterised by said cylindrical rotating beater wheel comprising an input element of an instrument for measuring entity characteristics.

Inventors: SHOFNER FREDERICK M, TOWNES MARK G, WILLIAMS GORDON F, SHOFNER, FREDERICK M., TOWNES, MARK G., WILLIAMS, GORDON F.
Applicants: ZELLWEGER USTER INC, ZELLWEGER USTER, INC.
Application year: 1993
Main classification: G01N33
IPC codes: G01N1, D01H5, G01N33, D01G99