Title of Invention

A DRAWING FRAME FOR MEASURING THE THICKNESS OF A RUNNING FIBRE STRUCTURE MADE OUT OF FIBRE BANDS

Abstract

The invention relates to a device (2) in a drafting frame (1) for measuring the thickness of a running fibre structure made out of fibre bands (5a-5n) comprises a tape guide (6) guiding the side by side running fibre bands thereon on a single plane, a measuring member(9), and a plurality of feeler elements (30a-30n) movably secured to the measuring member (9) to be movale in a direction transverse to the plane. Each fibre band (5a) is contacted by a separate feeler element (30a) for causing excursions thereof by thickness fluctuations of the running fibre band. Each sensor element (43) is yieldingly pressed against a respective fibre band, and each feeler element (30a) cooperates with the tape guide (6) for pressing the running fibre bands (5a) against a counterface (36). A summation device (39) adds the excursions of the feeler elements (30a) and a converter means (26) converts the excursion values into electric pulses. Figures 1& 5.

Full Text

BACKGROUND OF THE INVENTION This invention relates to a device in a drafting frame for measuring the thickness of a running fibre structure made out of fibre bands. A tape guide is arranged at the inlet of the drafting unit of the drafting frame for the fibre structure which is composed of side- by-side inputted fibre bands. The fibre bands are guided in a single plane through a measuring member which includes movable feeler elements which, in cooperation with a counterface, forms a throat through which the fibre bands pass after being compressed thereby. The positional changes of the feeler element in response to thickness fluctuations of the running fibre structure formed of the fibre bands are converted into electric control pulses by a converter means. According to a known device which measures the thickness of a fibre structure and which includes a tape guide for guiding the fibre structure drafting at the drafting unit inlet, the walls of the device converge at least partially conically to gather the fibre bands inputted in one plane. Further, a roll pair is arranged downstream of the tape guide. The fibre bands again diverge downstream of the roll pair. The thickness measuring device has a, movable feeler element which forms a throat with a stationary counterface for the throughgoing fibre structure as outlined above. The thickness of the fibre bands is sensed as the compressed fibre bands are guided in the tape guide side-by-side, while the roll pair withdraws the sensed fibre bands. It has further been proposed to compress the side-by-side arranged fibre bands from above across the width of the fibre structure. For this purpose the feeler element, in addition to a sensing and compression movement in the direction of the fibre bands, also executes a pivotal motion about an axis which is parallel to the running direction of the fibre bands and thus the feeler element is able to detect that, for example, fibre bands of unlike thickness are arranged side-by-side. The movable feeler element has a slide face by means of which the fibre bands are, in their side-by-side relationship, compressed and pressed against the stationary counterface. Disadvantageously, in such an arrangement the thickest fibre band determines the distance between the feeler element and the counterface, and even a small thickened location in one of the fibre bands results in a greater distance. The fibre bands on either side of such a thickened location are thus pulled out of the thus-obtained clearance without having been submitted to thickness sensing. SUMMARY OF THE INVENTION It is an object of the invention to provide an improved device of the above-outlined type from which the discussed disadvantages are eliminated and which, in particular, ensures a significantly improved detection of the thickness fluctuations of the fibre bands and makes possible a more accurate guidance thereof. This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the device for measuring the thickness of a plurality of side-by-side running fibre bands includes a supporting surface guiding the side-by-side running fibre bands thereon in a single plane; a retaining element; and a plurality of feeler elements movably secured to the retaining element to be movable in a direction transverse to the plane. Each fibre band is contacted by a separate feeler element for causing excursions thereof by thickness fluctuations of the running fibre band. Each feeler element is yieldingly pressed against a respective fibre band, and each feeler element cooperates with the supporting surface for pressing the running fibre bands against the supporting surface. A summation device adds the excursions of the feeler elements, and a converter means converts the excursion values into electric pulses. By means of the invention according to which all fibre bands are individually measured for thickness at the inlet of the drawing frame, a differentiated summation result may be obtained in which the thickness of each individual fibre band is taken into account. In this manner the evening of thickness fluctuations of all fibre bands is significantly improved, eventually resulting in a more uniform drawn fibre band, and thus an improved yam may be manufactured. The invention includes the following additional advantageous features: AH feeler elements are connected with a retaining element which is biased by a force- exerting member and to which the sum of the displacements of the individual feeler elements is applied. The feeler element is biased by a spring or the like. The feeler elements are constituted by leaf springs. The leaf springs are cantilevered. The counterface is the circumferential surface of a rotating roll. The measuring member is arranged upstream of the tape guide. The measuring member is integrated in the tape guide. The feeler elements are connected with a rotatably or shiftably supported retaining element which is biased by a force-exerting member and to which the sum of the displacements of the individual feeler elements is applied and wherein the end of the feeler elements includes a securing region fixedly connected with the retaining element and further wherein the feeler elements form a moving means for the rotary of shifting motion of the biased retaining element and the sensing region is formed by the other end of the feeler elements. The feeler elements are leaf springs. The feeler elements lie against the end face of a feed table. A clearance is provided between the free ends of the feeler elements and the free end of the feed table. The feed table or the feed roll are supported in a movable, spring-biased manner; the biasing springs are harder than the springs constituting the feeler elements. The feed table is stationarily held relative to the direction of excursion of the feeler elements. One end of the feeler elements may lift off the retaining element. An abutment is provided for limiting the excursion of the feeler elements. The leaf springs are arranged parallel to one another. The leaf springs are soft in the direction of the displacement of the feed table. The leaf springs are stiff in the direction oriented from the feed table to the retaining element. The retaining element is a longitudinal beam. The retaining element extends parallel to the feed roll. The retaining element is resistant to torsion forces. At the end face of the retaining element at least one torsion bar is disposed in an axial direction. The retaining element is supported in a rotary bearing at least at one end thereof. A measuring element detects the rotary motion of the retaining element. The measuring element is an inductive path sensor. The measuring element includes expansion strips. In a device in which the thickness variations are mechanically sensed over the width of the fibre structure by the individual feeler elements, the thickness deviations are summarized by the common retaining element by means of forming an average value. The inputted fiber quantity for the drawing frame is altered as a function of the deviation of the actual value (average value) from a desired value. The feeler elements are situated above the rotary roll forming a counter surface. The leaf springs extend into the bight between two cooperating rolls between which the fibre bands pass. The feed roll is stationarily supported. The retaining element is a hollow extruded member. The extruded retaining element is of aluminum or an aluminum alloy. The retaining element is provided at its end faces with a radially extending axle such as a bar or a pin. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a schematic side elevational view, with block diagram, of a regulated drawing frame incorporating the invention. FIG. 2a is a schematic sectional front elevational view of a preferred embodiment of the invention comprising a plurality of feeler elements and a stationary counterface. FIG. 2b is a schematic side elevational view of the construction shown in FIG. 2a. FIG. 3a is a schematic perspective view of another preferred embodiment comprising a plurality of feeler elements and a rotary counterface. FIG. 3b is a schematic side elevational view of the structure shown in FIG. 3a. FIG. 4 is a schematic side elevational view of a variant of the construction shown in FIGS. 3a and 3b. FIG. 5 is a schematic perspective view of yet another preferred embodiment of the invention comprising two cooperating transporting rolls. FIG. 6a is a schematic top plan view of a preferred embodiment comprising a tape guide with an integrated measuring device. FIG. 6b is a sectional front elevational view of the embodiment of FIG. 6a. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a drawing frame 1 which may be an HSR model manufactured by Trutzschler GmbH & Co. KG. The drawing frame 1 has a drafting unit 2 flanked upstream and downstream by a drafting unit inlet 3 and a drafting unit outlet 4, respectively. The fibre bands 5 are withdrawn from coiler cans and enter a tape guide 6 and are thereafter pulled therethrough by cooperating withdrawing rolls 7, 8 to cause the fibre bands 5 to run past the measuring member 9. The drafting unit 2 is a four-over-three drafting unit, that is, it has a lower output roll I, a lower mid roll II and a lower input roll III as well as four upper rolls 11, 12, 13 and 14. In the drafting unit 2 a drawing (stretching or drafting) of the fibre structure formed of a plurality of fibre bands 5 takes place. The drafting unit has preliminary and principal drawing fields. The roll pairs 14/111 and 13/11 constitute the preliminary drawing field while the roll pair 13/11 and the roll unit 11,12/1 form the principal drawing field. At the drafting unit outlet 4 the drawn fibre bands 5 reach a tape guide 10 and are pulled through a sliver funnel 17 by means of withdrawing rolls 15, 16 and are combined by the sliver funnel 17 into a fibre band 18 which is subsequently deposited into coiler cans. The withdrawing rolls 7, 8, the lower intake roll III and the lower mid roll II which are coupled to one another mechanically, for example, by a toothed belt, are driven by a variable speed motor 19 with a pre-inputted desired value. The upper rolls 14 and 13 are driven by friction from the respective lower rolls III and II. The lower output roll I and the withdrawing rolls 15, 16 are driven by a main motor 20. The variable speed motor 19 and the main motor 20 are provided with a respective regulator 21 and 22. The rpm regulation is effected by means of a closed regulating circuit in which a tachometer 23 is coupled with the variable speed motor 19 and a tachometer 24 is coupled with the main motor 20. At the drafting unit inlet 3 a magnitude of the fibre band which is proportional to the fibre band mass, such as its cross section, is measured by the inlet measuring member 9. At the drafting unit outlet 4 the cross section of the exiting fibre band 18 is determined by a fibre band outlet measuring organ 25 associated with the funnel trumpet 17. A central computer unit 26 (control-and-regulating device), such as a microcomputer or a microprocessor transmits to the regulator 21a setting of the desired magnitude for the variable speed motor 19. The measuring magnitudes of the two measuring members 9 and 25 are applied to the central computer unit 26 during the fibre band drawing process. The central computer unit 26 determines the desired value for the variable speed motor 19 from the measuring values of the inlet measuring member 9 and from the desired value for the cross section of the exiting fibre band 18. The measuring values of the outlet measuring member 25 serve for monitoring the exiting fibre band 18. With the aid of such a regulating system fluctuations in the cross section of the inputted fibre bands 5 may be compensated for by a suitable regulation of the drawing process and thus an evening of the outputted fibre band 18 may be achieved. According to FIGS. 2a and 2b, a plurality of side-by-side arranged feeler elements 30 are provided which are displaceable in the direction of the arrows B and C perpendicularly to the plane in which the fibre bands 5 lie. With one end of each feeler element 30 a respective spring 31 is associated which, at its other end, is secured to a throughgoing stationary retaining element 32. With each feeler element a converter means, such as an inductive path sensor is associated which converts the excursions of the feeler elements 30 into electric signals which are applied to a common electric adding device 34. The summation signal 35 is used for regulation as shown in FIGS. 1 and 3b. A throughgoing stationary slide element (supporting surface) such as a slide strip faces the other end of the feeler elements 30. The fibre bands 5 pass between the feeler elements 30 and the slide element (counterface) 36. Downstream of the measuring device 9 two cooperating driven rotary transport rolls 37 and 38 are arranged. In this manner, the thickness of all fibre bands 5 is individually measured at the inlet of the drawing frame, and a summation signal 35 is formed from the individual measuring signals. According to FIGS. 3a and 3b, the feeler elements 30 are formed by a plurality of side- by-side arranged leaf springs (measuring plates) which are affixed at one end to a common summation retaining element 39 such as a summation beam, a measuring lever or the like. The other, free end of the leaf springs 30 is pressed against the respective fibre bands 5. The mechanical summation retaining element 39 is at both ends rotatably supported in bearings 40, 41 and is biased by a spring 42 in a clockwise direction as viewed in FIGS. 3a and 3b. Further, with the summation retaining element 39 a sensor 43 is associated which, according to FIG. 3b, applies an electric summation signal to a regulator 44 connected to a drive motor 45 which rotates a roll 46. The roll 46 which rotates in the direction F forms a movable counterface (supporting surface) for all the leaf springs 30. Between the retaining element 39 and the roll 46 a throughgoing feed table 47 is disposed for pivotal motion about a support 48 biased clockwise by a spring 49. The fibre bands 5 are pulled in between the nip defined by the roll 46 and the feed table 47. At the output side of the nip the fibre bands 5 are sensed for thickness by the leaf springs 30 which are movable in a direction indicated by the arrows E and D. This embodiment needs only a single sensor 43 sensing the rotary displacement of the summation element 39. According to FIG. 4, the roll 46 is associated with a guide roll 50 which rotates in the direction G and which serves for guiding and advancing the fibre bands 5. Turning to FIG. 5, the roll 46 is associated with a transporting roll 37. The rolls 37, 46 rotate in the direction of the respective arrows H and I and define a bight, terminating in a nip through which the fibre bands 5 pass. The leaf springs (sensors) 30 extend into the bight and press on the fibre bands 5 from above, while the rotating upper face of the roll 46 serves as a counterface (supporting surface). FIGS. 6a and 6b show an embodiment where the measuring device 9 is integrated in the tape guide 6 having lateral walls 6a and 6b and a bottom wall 6c. The leaf springs 30 cantilevered to the summation retaining element 39 press down on a respective fibre band 5 with their other, free end. This arrangement makes possible to sense a varying number of fibre bands, for example, instead of the shown eight fibre bands, only six fibre bands may be sensed. The lateral walls 6a, 6b cause the fibre bands to laterally converge, that is, the fibre structure is laterally compressed independently from the number of the fibre bands 5. With each fibre band 5 a respective feeler element 30 may be associated so that an individual measuring of the fibre bands 5 is achieved. It is, however, also feasible to associate a plurality of feeler elements 30 with a single fibre band 5 or to assign a single feeler element 30 with more than one fibre band 5. The summation retaining element 39 serves in each instance for adding the excursions of the feeler elements 30. In this manner, a differentiated summation is achieved. It will be understood that the above description of the present invention is susceptible to various modification, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. We Claim: 1, A drawing frame (1) comprising; (a) apiurality of fibre band drawing roll pairs (I, II, III, 11, 12,13,14) (b) means (6) for simultaneously advancing a plurality of side-by-side running fibre bands (S) through said roll pairs; (c) means for combining(17) the fibre bands(5) to form an output fibre band (18); (d) means for discharging the output fibre band; and (e) a drafting unit (2) for detecting thickness variations of the side-by- side running fibre bands; said drafting unit (2) comprising; (1) a supporting surface (36) guiding the side-by-side running fibre bands(5) thereon in a single plane; (2) a retaining element(39); (3) a plurality of feeler elements (30) movably secured to said retaining element (39) to be movable in a direction transverse to said plane; each fibre band (5) being contacted by a separate said feeler element (30) for causing excursions thereof by thickness fluctuations of the running fibre band (5); (4) pressing means(31) for yieldingly pressing each said feeler element (30) against a respective said fibre band (5); each feeler element (30) cooperating with said supporting surface (36) for pressing the running fibre bands (5) against said supporting surface (36); (5) summation means (35) for adding the excursions of said feeler eiements(30); and (6) converter means (34) for converting excursion values into electric pulses representing the thickness variations of the running fibre bands (5) 2. The drawing frame as claimed in claim 1, comprising : (a) means (40, 41) for rotatably supporting said retaining element (39), said feeler elements (30) being secured to said retaining element (39) such that said feeler elements (30) exert a first torque on said retaining element (39); said first torque representing a sum of excursions of said feeler elements (30); and (b) resilient means(43) continuously exerting a second torque to said retaining element (39); said second torque opposing said first torque. 3. The drawing frame as claimed in claim 1, wherein said pressing means comprises a separate spring (31) engaging respective said feeler etements(30) 4 The drawing frame as claimed in claim 1, comprising an abutment (32) for limiting excursions of said feeler elements (30). 5. The drawing frame as claimed in claim 4, wherein said feeler elements (30) are leaf springs; 6. The drawing frame as claimed in claim 1, comprising a feed table (47) cooperating with said supporting surface (36) to define therewith a nip through which said fibre bands (5) pass; means (48) for movably supporting said feed table (47) in a direction of motion; 7. The drawing frame as claimed in claim 6, wherein said leaf springs (30) are relatively soft in said direction of motion of said feed table (47) and said leaf springs (30) are relatively hard in a direction oriented from said feed table (47) to said retaining element (39). 8. The drawing frame as claimed in claim 1, wherein said retaining element (39) is a longitudinal beam. 9. The drawing frame as claimed in claim 1, comprising (a) means (40, 41) for rotatably supporting said retaining element (39); and (b) a measuring element (9) connected to said retaining element (39) for measuring rotary displacements of said retaining element (39) caused by excursions of said feeler elements (30). 10. The drawing frame as claimed in claim 9, wherein each leaf spring (30) has opposite first and second end portions (31, 32); said leaf springs (30) being attached to said retaining element (39) at said first end portion (31) and cooperating with said supporting surface (36) at said second end portion (32). 11. The drawing frame as claimed in claim 1, comprising a rotary roll (46) having a circumferential face constituting said supporting surface (48). 12. The drawing frame as claimed in claim 11, wherein said rotary roll (46) has a rotary axis (F), and wherein said retaining element (39) is a longitudinal beam oriented parallel to said rotary axis. 13. The drawing frame as claimed in claim 11, wherein said rotary roll is horizontally oriented, and wherein said feeler elements (30) are disposed above said rotary roll (46). 14. The drawing frame as claimed in claim 11, wherein said rotary roll (46) is a first rotary roll and said feeler elements are leaf springs (30); 15. The drawing frame as claimed in claim 11, comprising a second rotary roll (37) cooperating with said First rotary roll and defining a bight therewith; said leaf springs (30) having an end extending into said bight. 16. The drawing frame as claimed in claim 11, comprising a feed table (47) cooperating with said rotary roll (46) to define therewith a nip through which said fibre bands pass; said feed table (47) having an end face, and said feeler elements (30) lying against said end face. 17. The drawing frame as claimed in claim 16, wherein each said feeler element(30) has a free end arranged to engage a respective said running fibre band (5), said free end of said feeler elements(30) being spaced from said end face of said feed table(47). 18 The drawing frame as claimed in claim 17, comprising a spring (49) urging said rotary roll (46) and said feed table (47) to one another; said spring (49) being harder than said leaf springs (30). 19, The drawing frame as claimed in claim 17, comprising means (48) for movably supporting said feed table (47); said means for movably supporting said feed table comprising means for preventing displacements of said feed table in a direction parallel to excursions of said feeler elements. The invention relates to a device (2) in a drafting frame (1) for measuring the thickness of a running fibre structure made out of fibre bands (5a-5n) comprises a tape guide (6) guiding the side-by-side running fibre bands thereon on a single plane, a Measuring member (9), and a plurality of feeler elements (30a- 30n) movably secured to the measuring member (9) to be movable in a direction transverse to the plane. Each fibre band (5a) is contacted by a separate feeler element (30a) for causing excursions thereof by thickness fluctuations of the running fibre band. Each sensor element (43) is yieldingly pressed against a respective fibre band, and each feeler element (30a) cooperates with the tape guide (6) for pressing the running fibre bands (5a) against a counterface (36). A summation device (39) adds the excursions of the feeler elements (30a), and a converter means (26) converts the excursion values into electric pulses.

Documents:

1465-cal-1998-granted-abstract.pdf

1465-cal-1998-granted-claims.pdf

1465-cal-1998-granted-correspondence.pdf

1465-cal-1998-granted-description (complete).pdf

1465-cal-1998-granted-drawings.pdf

1465-cal-1998-granted-form 1.pdf

1465-cal-1998-granted-form 2.pdf

1465-cal-1998-granted-form 3.pdf

1465-cal-1998-granted-form 5.pdf

1465-cal-1998-granted-letter patent.pdf

1465-cal-1998-granted-pa.pdf

1465-cal-1998-granted-priority document.pdf

1465-cal-1998-granted-reply to examination report.pdf

1465-cal-1998-granted-specification.pdf

1465-cal-1998-granted-translated copy of priority document.pdf