Abstract:
A fiber tuft feeder includes a reserve chute; a feed roll supported in the reserve chute at an outlet thereof; a countersupport cooperating with the feed roll for defining therewith a nip through which the feed roll draws fiber tufts from the reserve chute; an opening roll supported immediately downstream of the nip for receiving fiber tufts from the nip; and a feed chute having an inlet connected to the outlet of the reserve chute. A relative motion of the feed roll and the countersupport toward and away from one another is permitted for varying the distance between the feed roll and the countersupport by the fiber tufts passing therebetween. Further, a spring is provided which resiliently urges the feed roll and the countersupport towards one another.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of Federal Republic of Germany Application No. P 40 01 817.2 filed Jan. 23, 1990, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus for feeding fiber tufts such as cotton or chemical fiber tufts to a fiber processing machine such as a card, a roller card unit, a cleaner or the like. 
     The apparatus has a reserve chute chargeable with fiber tufts, a take-in mechanism such as a slowly rotating feed roll, a countersupport cooperating with the feed roll for forming a nip to advance the fiber material therebetween, an opening device, such as a rapidly rotating opening roll arranged immediately downstream of the feed roll and a feed chute which receives the fiber material from the feed roll and the opening roll. 
     In a known device where the gap defined by the feed roll and the countersupport is constant (for example, 5 mm), only a predetermined fiber flow rate, for example, 360 kg/h per m width may be achieved. Further, upon changes in the type of the fiber material and the behavior of the fiber, problems are often encountered concerning the clamping in the nip defined by the feed roll and the countersupport, since the clamping behavior differs dependent upon the hardness or softness of the fiber material. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved apparatus of the above-outlined type from which the discussed disadvantages are eliminated and which, in particular, achieves an alteration of the fiber material quantity passing through the nip defined by the feed roll and the countersupport and, at the same time ensures a secure clamping of the fiber material. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the fiber tuft feeder includes a reserve chute; a feed roll supported in the reserve chute at an outlet thereof; a countersupport cooperating with the feed roll for defining therewith a nip through which the feed roll draws fiber tufts from the reserve chute; an opening roll supported immediately downstream of the nip for receiving fiber tufts from the nip; and a feed chute having an inlet connected to the outlet of the reserve chute. A relative motion of the feed roll and the countersupport toward and away from one another is permitted for varying the distance between the feed roll and the countersupport by the fiber tufts passing therebetween. Further, a spring is provided which resiliently urges the feed roll and the countersupport towards one another. 
     By virtue of the invention which thus provides for a spring-biased relative displacement of the feed roll and the countersupport towards or away from one another, there is achieved an automatic alteration of the intake gap (nip), making possible, for example, a larger throughput, such as, for example, 500 kg/h per m width or more. It is a further advantage of the invention that for each type of material the feed roll securely clamps the fiber material against the countersupport, that is, a more uniform throughput of material is effected. A manual adjustment or re-adjustment of the feed roll may thus be dispensed with. It is a further advantage of the invention that the displacements of, for example, the feed roll may be utilized as a measuring magnitude for a regulated setting member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1a is a schematic side elevational view of a tuft feeder incorporating a preferred embodiment of the invention. 
     FIG. 1b is a top plan view of a component of the construction shown in FIG. 1a. 
     FIGS. 2-6 are schematic side elevational views of five additional preferred embodiments of the invention. 
     FIG. 7 is a schematic side elevational view of a tuft feeder different from that shown in FIG. 1a and incorporating the preferred embodiment of FIGS. 1a and 1b. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning to FIG. 1a, there is illustrated therein a tuft feeder adapted for use to advance a fiber lap to a carding machine. The tuft feeder which may be of a general construction corresponding to an EXACTAFEED FBK model, manufactured by Trutzschler GmbH &amp; Co. KG, Monchengladbach, Germany, has a vertically oriented reserve chute 1 which is charged with fiber tuft from above, for example, from an overhead distributor duct 1a after the material has passed through a condenser (not shown). In an upper zone of the reserve chute 1 air outlet openings 1b are provided through which the conveying air stream passes after separation of the fiber tufts and enters a suction device 1c as indicated by the arrow A. 
     The lower end of the reserve chute 1 is obturated by a feed roll 2 which rotates counterclockwise as indicated by the arrow 2a and which cooperates with a fixed feed lip 13. The feed roll 2 and the feed lip 13 together define a nip (fiber guiding channel) 12a. Immediately downstream of the fiber guiding channel 12a--as viewed in the direction of fiber advance--there is arranged an opening roll 3 which rotates clockwise as indicated by the arrow 3a and which may have pins or a sawtooth clothing on its surface. One part of the circumferential surface of the opening roll 3 bounds an upper, intake end of a feed chute 4. The opening roll 3 advances the fiber material into the feed chute 4. The feed lip 13 has a terminal edge 13a oriented in the direction of rotation of the adjacent portions of the feed roll 3. 
     The feed chute 4 has at its lower end two cooperating delivery rolls 5 which rotate as designated by the respective arrow and which withdraw the fiber material from the feed chute 4 and advance the same as a fiber lap on a feed tray 5a to the non-illustrated carding machine. 
     The walls of the feed chute 4 are, along a length portion in the lower part thereof, provided with air outlet openings 6. The upper end of the feed chute 4 communicates with a duct 7 whose upper end adjoins the pressure side of a blower 8. The rotating feed roll 2, in cooperation with the feed lip 13, and the opening roll 3 continuously deliver, at a determined flow rate, fiber material into the feed chute 4 and, at a similar flow rate, fiber quantities are withdrawn by the delivery rolls 5 from the feed chute 4 and deposited on the feed tray 5a. 
     To uniformly densify and to maintain constant the fiber quantities, the blower 8 generates a compressing air stream B which is directed downwardly into the feed chute 4. The blower 8 draws air from a suction channel 9 whose lower end communicates the air outlet openings 6 provided in the feed chute 4 and drives compressed air down through the duct 7 through the fiber column in the feed chute 4 and out of the air outlet openings 6 as indicated by the arrows C. 
     The opening roll 3 is surrounded by a housing 10 formed of two arcuate wall portions 10a and 10b while the feed roll 2 is surrounded by a wall 11, as shown in FIG. 2. The wall 11 as well as the wall portions 10a, 10b conform to the curvature of the feed roll 2a and the opening roll 3, respectively. The housing portions 10a and 10b are separated from one another by a clearance 12b which forms the upper, intake end of the feed chute 4 and through which thus the fiber material is advanced into the feed chute 4 by the opening roll 3. The densifying air flow B proceeds codirectionally with the rotation of the adjoining circumferential portion of the opening roll 3. 
     As shown in FIG. 1b, the opposite stub shafts 2c of the feed roll 2 are supported in respective rotary bearings 16 supported with the intermediary of respective compression springs 14 at two fixed surfaces 15 which form part of the walls of the reserve chute 1. 
     Reverting once again to FIG. 2, each rotary bearing 16 is held on the respective support 15 by means of a bar 29 which is surrounded by a compression spring 14 and which passes through an opening 30 provided in the support 15. At the end of the bar 29, remote from the rotary bearing 16, there is a plunger armature 17a which cooperates with a solenoid 17b. The assembly 17a, 17b forms an inductive path sensor 17 which is connected with a regulatable drive motor 19 for the feed roll 2 with the intermediary of a regulator 18. If, for example, the fiber quantity passing through the nip 12a increases, the feed roll 2 is radially displaced in the direction of the arrow D whereupon the compression spring 14 exerts a counterforce in the direction of the arrow E. The counterforce is thus applied to the feed roll 2 which then firmly clamps the fiber material against the feed lip 13 thus preventing the opening roll 3 from tearing an entire batch of fibers from the outlet side of the nip 12a. In this arrangement both the feed roll 2 and the opening roll 3 rotate in the same sense in a counter-clockwise direction. 
     Turning to FIG. 3, in the embodiment shown therein there is provided a lever arm 20a, one end of which is held in a stationary pivotal support 31. The lever arm 20a is thus able to execute swinging motions thereabout towards or away from the feed lip 13 as indicated by the arrows F, G. The other end of the lever arm 20a is connected by means of a tension spring 21a with a stationary support 22. The lever arm 20a supports a bearing bracket 20b which holds the stub shaft 2b of the feed roll 2. Further, the mid zone of the lever arm 20a engages a stationary abutment 24, thereby ensuring a minimum clearance for the fiber guiding channel (nip) 12a. Advantageously, the feed lip 13 is provided, on its surface oriented towards the feed roll 2, with a low-friction coating 13b, such as a Teflon layer. 
     Turning to the embodiment illustrated in FIG. 4, there is provided a lever arm 23a which is at one end articulated to a stationary pivot 35. At the opposite end the lever arm 23a carries the rotary bearing 16a of the feed roll 2. The lever arm 23a is, by means of a compression spring 25a, held on a stationary support 26, biased against a stationary abutment 24. The lever arm 23a is pivotal in the direction of the arrows I, H. 
     Turning to the embodiment illustrated in FIG. 5, there are provided two feed rolls 2&#39; and 2&#34;. The feed roll 2&#34; is stationarily supported and constitutes a countersupport for the feed roll 2&#39; to define a nip 12c therewith. The rotary bearing 16 of the feed roll 2&#39; is movably supported by means of the compression spring 14 on a stationary support 15 for excursions radially towards or away from the feed roll 2&#34;. 
     Turning now to the embodiment illustrated in FIG. 6, the feed roll 2 is stationarily supported and cooperates with a feed lip 13&#39; which is pivotally secured at one end at 32. A compression spring 27 is, with one end, in engagement with a stationary support 28 and presses, with its other end, the feed lip 13&#39; towards the feed roll 2. 
     FIG. 7 shows a fiber feeder in which the fiber tufts fall from the opening roll 3 onto a conveyor belt 34 to form a deposited layer thereon. The feed roll 2 is movably supported similarly to the embodiment described in connection with FIG. 1a. Between the opening roll 3 and the conveyor belt 30 the fiber tufts are in a free fall through a feed chute, such as a space 33 without pneumatic densification as it was the case in the construction described in connection with FIG. 1a. 
     It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.