Abstract:
An opening roller for removing tufts from fiber bales includes a cylindrical core adapted to be supported for rapid rotation and annular toothed discs affixed peripherally to the cylindrical core. The toothed discs which have teeth adapted to penetrate into the fiber bales upon rotation of the cylindrical core are arranged to have a helical course.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an opening roller for removing material from fiber bales such as cotton bales or chemical fiber bales and is the type which is provided with toothed discs mounted on a cylindrical roller core which is rotated during operation. The teeth project between bars of a hold-down grate and extend into the fiber material. 
     German Pat. No. 1,131,567 to which corresponds U.S. Pat. No. 3,101,513, discloses an opening roller whose toothed discs are of planar configuration and are arranged at an oblique angle relative to the roller axis whereby, during rotation, each disc wobbles relative to a fixed point externally of the opening roller. By virtue of the oblique positioning of the toothed discs disadvantageous transverse forces are generated between the toothed discs on the one hand and the fiber bale on the other hand. It is also a disadvantage that mounting and securing the obliquely arranged toothed discs on the opening roller involve significant manufacturing expenses. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved opening roller of the above-outlined type which is so structured that transverse forces acting on the teeth are, for all practical purposes, eliminated and further, the manufacture of the opening roller is significantly simplified. 
     These objects and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the toothed discs have a helical course. 
     By virtue of the helical configuration of each toothed disc transverse forces on the teeth during the removal of fiber material from the bales will not be generated. The teeth of the toothed disc sink in succession into the surface of the bale thus working within a certain band zone as viewed in the width of the bale (that is, as viewed parallel to the roller axis). By virtue of the helical configuration the pressure exerted by the fiber bale on the opening roller is reduced so that the feed of the opening roller towards the surface of the fiber bale may be less, resulting in finer removed tufts. Furthermore, the use of the opening roller according to the invention results in an equalization of the manufacturing process. It is a particular advantage of the invention that the helical toothed discs may be manufactured in a simple manner and may be mounted on the roller core simply and rapidly; this represents a significant manufacturing advantage. Also, by practicing the invention, the overall number of the toothed discs may be reduced. 
     According to a further feature of the invention the opening roller has toothed discs of left-hand and right-hand helical course. By virtue of this feature an axial pressure or an imbalance may be reduced or eliminated altogether, in case the teeth are not aligned mechanically. 
     According to a further preferred feature of the invention, the toothed disc has between three to eight teeth. Preferably, the toothed disc has at least one opening slot (discontinuity). The toothed discs may be made in a simple manner by punching from a sheet metal blank, providing an opening slot and then bending into a helical configuration. Preferably, the toothed disc has a free circumferential length portion between two consecutive teeth. In this manner, the weight of the toothed disc is reduced, whereby a significant weight reduction is achieved if a great number of toothed discs are used on the opening roller. Preferably, the toothed disc is made of at least two parts. This makes possible to manufacture and mount the toothed discs on the roller core in segments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a schematic side elevational view of a fiber bale opening device incorporating the invention. 
     FIG. 2 is a schematic perspective view of a preferred embodiment of the invention. 
     FIG. 3 is an end view of a structure similar to that illustrated in FIG. 2. 
     FIG. 4 is a perspective view of a component of the construction shown in FIG. 2. 
     FIG. 5a is a schematic side elevational view of another bale opening device incorporating the invention. 
     FIG. 5b is a schematic top plan view of the construction shown in FIG. 5a with cover removed. 
     FIG. 5c is a schematic, partially diagrammatic view of a second preferred embodiment of the invention incorporated in the construction shown in FIGS. 5a and 5b. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning to FIG. 1, there are shown a plurality of stationary fiber bales 1 serially arranged along rails (not shown) on which a carriage (also not shown) of a fiber bale opening device may travel back and forth. On the carriage there is mounted a vertically displaceable opening device which includes a housing 2, a grate 3 formed of a plurality of grate bars 3a (only one shown in FIG. 1) secured to the housing at 3b for pivotal motion in a vertical plane, an opening roller 4 and a suction duct 5 to withdraw fiber tufts from the housing 2 after they are thrown thereinto from the fiber bales by the opening roller 4. Such a bale opener may be, for example, a &#34;BLENDOMAT BDT&#34; model, manufactured by Trutzschler GmbH &amp; Co. KG, Monchengladbach, Federal Republic of Germany. As shown in FIG. 1, the opening device, during fiber removal from the bales, moves in the direction of the arrow A. The grate 3 is oriented in such a manner that its grate bars 3a project between circumferential gaps defined between teeth 9 of the rapidly rotating opening roller 4. The teeth 9 project into the upper surface of the fiber bales 1. The grate 3 serves as a hold-down device with those portions of the grate bars 3a which engage the fiber bale. Upstream and downstream of the opening roller 4 there are arranged two axially parallel pressing rollers 6 and 7 which press on the upper face of the fiber bales 1 to ensure that the latter remain stationary and are thus secured against shifting or tipping over. 
     The opening roller 4 is formed of a cylindrical core 10 to which there are secured, for example, by welding, toothed annular discs 8 whose teeth 9 project between adjoining grate bars 3a into the upper face of the fiber bales. The diameter of the cylindrical core 10 may be, for example, 50 to 600 mm. Each toothed annular disc 8 may have, for example, six teeth 9. The opening roller 4 rotates clockwise as indicated by the arrow B. Each toothed annular disc 8 has open ends defining a gap or discontinuity 11. The teeth 9 are oriented in the direction of rotation B. 
     Turning now to FIG. 2, there is illustrated therein a length portion of the opening roller 4, including a plurality of toothed annular discs 8 mounted on the core 10. Each toothed disc 8 has a helical course and thus the teeth 9 of each toothed disc 8 describe a helical path about the core 10. Adjoining helical toothed discs 8 are at an axial distance a from one another to accommodate respective grate bars 3a. The gap 11 defined by the open ends of each toothed disc 8 has an axially measured dimension b. Preferably, b=x(z-1)-c, wherein x is the axial distance between two adjoining teeth, for example, 4 to 20 mm, including the thickness of one toothed disc, z is the number of teeth and c is the thickness of the tooth in millimeter. The distance b may be approximately 10 to 80 mm. The distance a between two adjoining toothed discs preferably corresponds to the relationship a=(b+c)/(z-1)-c, and equals about 4 to 50 mm. 
     Turning now to FIG. 3, there is shown in end view an opening roller wherein each toothed disc 8 has five teeth 9. The angle α between circumferentially consecutive teeth 9 (belonging to axially adjoining consecutive toothed discs 8) corresponds preferably to the relationship α=282/ r  0.5, wherein r is the radius of the toothed disc center to the tooth tip and may be 75 to 350 mm. 
     Each toothed disc 8 has, between two consecutive teeth 9, 9&#39; a gap 11 whose circumferentially measured dimension is designated at d. Preferably, the teeth of the toothed discs are arranged on the cylindrical roller core in a screw-thread like fashion. This ensures that adjacent teeth extend into the bale surface in succession. 
     FIG. 4 illustrates helical toothed disc 8 having four teeth 9. The thickness of the disc 8 is designated at c. The axial offset between the open ends 8&#39;, 8&#34; of the toothed disc 8 is designated at b. 
     FIG. 5a illustrates schematically a bale opening device which has two opening rollers 4 and 4&#39;. The arrows C, C&#39; indicate the direction of rotation of the opening rollers 4, 4&#39;. The tips of the teeth 9 are oriented in the direction of rotation. The grate 3 extends underneath the opening rollers 4 and 4&#39; and may pivot about supports 3b. 
     The arrows D and D&#39; indicate successive operating directions in the two directions of motion. 
     FIG. 5b schematically shows the two opening rollers 4 and 4&#39; in top view indicating the course of the toothed discs 8 of the opening roller 4 and the toothed discs 8&#39; of the opening roller 4&#39;. The helical course of each toothed disc is effected by bending the discs in an S or Z form. About each toothed disc visible in FIG. 5b there is circumscribed a rectangle indicated in dash-dot lines to designate the zone within which the respective discs 8 and 8&#39; engage into the upper surface of the bale upon rotation of the opening rollers 4, 4&#39;. In the zone between two adjoining grate bars 3a each opening roller has two toothed discs arranged in opposite orientation, that is, they have a left-hand and, respectively, a right-hand helical course. 
     Turning to FIG. 5c, there is illustrated the cylinder core 10 of the opening roller 4 and there are diagrammatically shown the peripheral course lines 8a of each toothed disc (not shown). As viewed axially, the toothed discs have alternatingly a left-hand and a right-hand helical course. 
     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.