Abstract:
A coiler can for accommodating sliver includes a vertical wall defining an inner can space and a can top through which sliver may be deposited into and withdrawn from the can space; a vertically shiftable bottom disposed in the inner can space; and a tension device connected to the shiftable bottom and exerting a pulling force thereto toward the can top.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of German Application No. 100 40 066.3 filed Aug. 16, 2000, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a coiler can having a vertically shiftable bottom provided with an internal bottom lifting device. 
     In a known device of the above-outlined type, as disclosed, for example, in European Patent No. 0 452 687, the lifting device is composed of two compression springs and a pantograph-type balancing system which press against the shiftable bottom from below. During filling of the coiler can the sliver entering the coiler can presses the bottom downward. When the coiler can is filled, the two compression springs and the balancing system are compressed to a certain height. It is a disadvantage of this arrangement that the bottom is not capable of being lowered all the way to the lower end of the coiler can since the bottom lifting system is accommodated within the coiler can underneath the bottom. This results in a loss of coiler can volume for the sliver. It is a further drawback that the known arrangement is of expensive construction. 
     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, allows a capacity increase of the coiler can in a structurally simple manner. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the coiler can for accommodating sliver includes a vertical wall defining an inner can space and a can top through which sliver may be deposited into and withdrawn from the can space; a vertically shiftable bottom disposed in the inner can space; and a tension device connected to the shiftable bottom and exerting a pulling force thereto toward the can top. 
     By spring loading the shiftable bottom of the coiler can from above, the bottom can be lowered all the way to the lower end of the coiler can so that the coiler can may receive significantly greater sliver quantities than conventional coiler cans. A simple construction is feasible by arranging the tension element at least partially above the shiftable bottom. Also, the invention allows an economical manufacture of the coiler cans having a shiftable, spring-loaded bottom. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic side elevational view of a draw frame in the process of charging a flat coiler can with sliver. 
     FIG. 2 is a perspective view of a flat coiler can having a vertically shiftable internal bottom. 
     FIG. 3 a  is a schematic side elevational view of a flat coiler can incorporating a preferred embodiment according to the invention. 
     FIG. 3 b  is a sectional view taken along line IIIb—IIIb of FIG. 3 a.    
     FIG. 3 c  is an enlarged detail illustrating the securement of a rubber band to a stationary support. 
     FIG. 4 is a schematic front elevational view of another preferred embodiment, illustrating pressing and pulling forces affecting the shiftable bottom as the coiler can is being filled. 
     FIG. 5 is a schematic side elevational view of a further preferred embodiment including two tension springs and external projections affixed to the shiftable bottom. 
     FIG. 6 is a fragmentary front elevational view of yet another preferred embodiment showing a two-part tension element composed of an elastic and an inelastic part. 
     FIG. 7 is a schematic front elevational view of a further preferred embodiment of the invention including a one-piece elastic tension element. 
     FIG. 8 is a schematic front elevational view of a coiler can of yet another preferred embodiment having an endless, two-part elastic tension element. 
     FIG. 9 is a fragmentary front elevational view of a coiler can showing a tension element wound on a spring-loaded winch. 
     FIG. 9 a  illustrates a terminal region, on an enlarged scale, of the embodiment shown in FIG. 9 having a rotary spring. 
     FIG. 10 is a fragmentary front elevational view of a coiler can, illustrating an opening therein through which a tension element passes. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning to FIG. 1, coiler cans  1  of circular horizontal outline are positioned underneath a creel  2  of a draw frame which may be, for example, a high-performance HS model, manufactured by Trützschler GmbH &amp; Co. KG, Mönchengladbach, Germany. From each coiler can  1  a sliver  3  is withdrawn and introduced into a draw unit  4  in the direction A. After passing the draw unit  4  the processed sliver  5  is deposited in coils by a rotary head  6  of a sliver coiler in a coiler can  7  of flat, generally rectangular, horizontal outline. The coiler can  7  is positioned on a non-illustrated, driven sled for reciprocation in the direction of arrows B and C. The horizontal length dimension of the coiler can  7  extends parallel to the reciprocating direction B. C and its horizontal width generally corresponds to the deposited sliver coils. 
     Turning to FIG. 2, the flat coiler can  7  has a circumferential vertical wall composed of two identical panels which are made, for example, of a hard plastic material and which are joined along vertical seams  8   a  and  8   b . The vertical coiler can wall has opposite wide sides  7   a  and  7   b  and opposite narrow sides  7   c  and  7   d . The opposite narrow sides  7   c  and  7   d  are semicircular as viewed horizontally, to conform to the circular shape of the deposited sliver coils that adjoin the narrow sides  7   c  and  7   d . At the lower end of the coiler can  7  the vertical wall is closed by a fixed bottom  7   e . At the upper circumferential edge the vertical can wall is provided with a bead  9  which may be of metal and which secures the panels to one another. A similar bead may be provided along the lower circumferential edge of the vertical can wall. The coiler can  7  is open at the top. 
     A vertically shiftable bottom  12  which conforms to the horizontal outline of the coiler can  7  is positioned in the inner can space  10  and is vertically displaceable as indicated by the arrows D and E. 
     Turning to FIGS. 3 a ,  3   b  and  3   c , four flat rubber bands  13 , constituting tension elements, have one end secured to the bottom  12 , then extend upward within the coiler can  7  and are trained about a deflecting element constituted, for example, by the rounded and smooth top bead  9 . It is to be understood that the deflecting element may also consist of a roller. From the bead  9  the bands extend downward along the sides  7   a ,  7   b  and are trained about respective rounded deflecting surfaces  15 , and then extend upward and are, at their other end, attached to respective posts  14  secured to the outside of the can wall. A downward pressure on the bottom element  12  caused by the weight of the sliver is opposed by the upwardly pulling tension force of the elastic bands  13 . The resiliency of the elastic bands  13  is so designed that when the can is empty the bottom element  12  rises to the top of the can. By an appropriate coordination between the elasticity (spring characteristic) of the bands  13  and the weight of the sliver, a well-packed charging of the coiler can with sliver may be achieved. The fixed can bottom  7   e  has a very small distance (for example, 10 mm) from the floor on which the coiler can stands. Since the tension elements are not present in any way underneath the bottom  12 , the latter may sink all the way into contact with the fixed can bottom  7   e . The bottom  12  may be made, for example, of pressed synthetic material and may have a thickness of 10 mm. 
     In FIG. 4 the bottom  12  is depicted at about half-height of the coiler can  7 , indicating that the can is about half filled with sliver (not shown for clarity). The pressing force P 3  is the increasing weight of the sliver during the filling operation as well as the filling force exerted by the coiler head  6  as it presses down on the sliver. Such a filling force is greater than the force derived from the sliver weight. The composite pressing force P 3  is opposed by the tension force of the elastic elements  13 ; such a tension force is, on both sides of the can, composed of partial tension forces P 1  and P 2 . The elastic elements  13  are secured to the outside of the vertical can wall at respective posts  27 . 
     FIGS. 5-9 illustrate additional advantageous embodiments of the invention. 
     According to FIG. 5, the bottom  12  has, at its longitudinal ends, two extensions  16  which project in opposite directions through vertical slots provided in the two end walls  7   c  and  7   d  of the coiler can. Two tension springs  17  positioned at either end of the coiler can are secured to the respective projections  16  and a respective post  18  at the top of the coiler can. The tension springs  17  (which, as an alternative, may be elastic bands) exert an upwardly oriented tension force on the shiftable bottom  12 . 
     In FIG. 6 a tension element is shown which is a two-part component. One part, which is non-elastic, consists of a wear-resistant and tension-resistant smooth strap  20  made, for example, of textile, metal or a fiber-reinforced material. The strap  20  has one end which is secured to the bottom  12  and is trained about the top bead  9  to slide thereon. The other end of the strap  20  is secured to the second component of the tension element, consisting of a resilient member such as a tension spring  19  or a rubber band whose free end is secured to a post  19   a  affixed to the outside of the can wall at the lower end thereof. 
     According to FIG. 7, a one-piece tension element  21  is provided which may be an elastic band and which crosses the bottom  12  along its underside. For equilibrium and stability reasons, expediently two tension elements  21  are provided along the long side walls  7   a ,  7   b  of the can  7 . If desired, that portion of the tension elements  21  which engage and carry the bottom  12  may be non-elastic. 
     According to FIG. 8, an endless, two-part elastic tension element is provided whose one part is a non-elastic, wear-resistant belt  22  which passes underneath the bottom element  12  and externally along opposite vertical can walls and whose opposite ends are attached to an elastic tension element such as a spring  23 , a rubber band or the like, extending underneath the fixed can bottom  7   e.    
     According to FIG. 9 to the bottom  12  one end of a non-elastic band  24  is secured, whose other end is mounted on a winch  25  rotatable in the direction of the arrows F and G. The winch  25  is, as shown in FIG. 9 a , provided with a rotary spring device  26  exerting an elastic torque on the winch  25  in the direction G to cause the band  24  to exert a tension force P 1  in an upward direction on the bottom  12  against a pressing force P 3 . FIG. 9 only shows a single elastic, loaded tension element; for equilibrium and stability reasons expediently at least two tension elements are provided which can be rolled and unrolled by a respective winch  25 . 
     In FIG. 10, in the side wall  7   a  (as well as in the non-illustrated side wall  7   b ) a throughgoing opening  28  is provided through which the tension element may pass and may thus be deflected. The edge surface of the opening  28  is expediently rounded and smooth. 
     The tension and pressing forces shown in FIG. 4 apply equally to a sliver charging process, for example, at the outlet of a draw frame as shown in FIG. 1 or a sliver withdrawing process from the coiler can, for example, in an open-end spinning machine. 
     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.