Abstract:
A travelling flat bar includes a head, an opening in the head, a coupling element received in the opening and arranged for attaching the flat bar to a flat-moving chain and a securing (locking) arrangement for readily releasably retaining the coupling element in the opening. The locking arrangement cooperates with the coupling element for form-lockingly retaining the coupling element in the opening.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of Federal Republic of Germany application No. P38 14 412.3 filed Apr. 28th, 1988, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a travelling flat (flat bar) for a card, wherein the flat chains are releasably secured to the outer ends of the flat heads by means of a coupling element and further, in each head terminus an opening is provided for receiving the coupling element. 
     In a flat of known construction the attachment of the flat chain to the flat head is effected by a flat screw which passes through a bushing at the articulation of the chain and extends into a bore which is provided in the flat head and which has an inner thread. It is a disadvantage of this arrangement that providing the inner thread is technologically complex and further, in practice, the inner thread may tend to lead to breakages of the material in the thread zone. It is also a disadvantage of the prior art flat that the flat screw must be tightened with a predetermined torque which renders, for example, a reassembling operation after replacement of clothing, very time consuming since the torque limits have to be strictly observed. In case the screw is tightened excessively, the inner thread may break out which renders the flat useless and has to be replaced 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved flat of the above-outlined type from which the discussed disadvantages are eliminated and which permits in particular a simple manufacture, a rapid assembly (installation) and a reliable locking of the coupling element in the flat head. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the travelling flat bar includes a head, an opening in the head, a coupling element received in the opening and arranged for attaching the flat bar to a flat-moving chain and a securing (locking) arrangement for readily releasably retaining the coupling element in the opening. The locking arrangement cooperates with the coupling element for form-lockingly retaining the coupling element in the opening. 
     The form fitting (form locking) immobilization of the coupling element ensures a reliable locking thereof without the need of an inner thread in the flat head for the coupling element; a smooth bore, or aperture provided by milling suffices. The invention thus dispenses with a flat screw, and therefore time-consuming setting of the required torque is no longer necessary. Also, breakouts of the inner thread are no longer a problem. The immobilization of the coupling element for the flat chain has the particular advantage that assembly work on the flat chain can have a significantly shorter duration. Thus, the invention permits a simple preparation of the flat head and the coupling element as well as a rapid assembly of the flats, the coupling element and the chains. The coupling element is so constructed that an unintended outward movement thereof from the opening in the flat head is prevented while the flat chain pulls the flats along the carding cylinder during operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a schematic side elevational view of a carding machine incorporating the invention. 
     FIG. 2a is a fragmentary sectional elevational view of a flat head forming a component of a first preferred embodiment of the invention. 
     FIG. 2b is an elevational view of a coupling element forming another component of the first preferred embodiment of the invention. 
     FIG. 2c is a plan view of still another component of the first preferred embodiment of the invention. 
     FIG. 3a is a perspective exploded view of the components of the first preferred embodiment of the invention. 
     FIG. 3b is a perspective view of the components of the first preferred embodiment in an assembled state. 
     FIG. 4 is a front elevational view, partially in section, of a second preferred embodiment of the invention. 
     FIG. 5 is a sectional end view of a third preferred embodiment of the invention. 
     FIG. 6a is a front elevational view of a fourth preferred embodiment of the invention. 
     FIG. 6b is a perspective view of a component shown in FIG. 6a. 
     FIG. 7a is an elevational view of a component of a fifth preferred embodiment. 
     FIG. 7b is a sectional view of an enlarged detail of FIG. 7a. 
     FIG. 7c is a schematic side elevational view of a component of the fifth preferred embodiment cooperating with the component shown in FIGS. 7a and 7b. 
     FIG. 7d is a fragmentary front elevational view of the component of FIG. 7c. 
     FIG. 7e is a fragmentary top plan view of the component shown in FIGS. 7c and 7d. 
     FIG. 8 is a top plan view of a sixth preferred embodiment of the invention. 
     FIG. 9 is a front elevational view of a seventh preferred embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning to FIG. 1, there is illustrated a carding machine which may be, for example, an EXACTACARD DK 740 model, manufactured by Trutzschler GmbH &amp; Co. KG, Monchengladbach, Federal Republic of Germany. The carding machine has a feed roller 1, a feed table 2 cooperating therewith, a licker-in 3, a main carding cylinder 4, a doffer 5, stripping rollers 6, crushing rollers 7, 8, a web guiding element 9, a sliver trunpet 10, calender rollers 11, 12 as well as travelling flats 13 supported by end rollers 13a, 13b which are rotated in a direction opposite to that of the main carding cylinder 4. The flats (flat bars) 14&#39;, 14&#34;, 14&#39;&#34; are pulled by the flat chain 15 in the direction of the arrow A. As shown in FIG. 3b, the flat chain 15 is releasably secured by a coupling pin 16 to an end of the flat head 14a. According to the invention and as described in greater detail below, the coupling pin is retained in the flat head 14a in a form-locking manner and is thus prevented from unintentional removal from the flat head. 
     Turning to FIG. 2a, in the flat head 14a there is provided a blind bore 14c which extends parallel to the length dimension of the elongate flat (which, in turn, is oriented transversely to the direction of its travel). A slot 14d is provided in the flat head 14a in a direction transversely to the bore 14c and intersecting the same. FIG. 2b shows a coupling pin 16 adapted to be fitted into the bore 14c. The coupling pin 16 has a shank 16a and a head 16b. The shank 16a has a circumferential groove 16c. FIG. 2c illustrates a locking element formed of an elastic circlip 17 having a discontinuity at 17a and adapted to surround the groove 16c as will be discussed below. 
     FIG. 3a shows, in an exploded view, the relative position of the flat head 14a, the flat chain 15, the coupling pin 16 and the circlip 17, while FIG. 3b shows these components in an actual assembled state. The elastic circlip 17 is received in the slot 14d and, within the groove 14c, projects into the groove 16c of the pin shank 16a and closely surrounds the groove bottom after it has been snapped-in. 
     FIG. 4 illustrates a spring-biased locking arrangement, including a leaf spring 18 mounted at one of its ends on the flat head 14a by a screw 19. At its other end the leaf spring 18 carries a pin 20 which projects through a bore 14b in the flat head 14a and extends, with its free end, into the groove 16c of the coupling pin 16. 
     FIG. 5 illustrates an embodiment in which a bent spring 21 is secured at one end 21a to the flat head 14a. Adjacent its other end 21d, the spring 21 has an arcuate portion 21c which lies in the pin groove 16c, thus immobilizing (locking) the pin 16. 
     In the embodiment according to FIGS. 6a and 6b, the pin locking arrangement comprises a yoke 22 which has a leg portion 22a provided with a bore hole 22b, an oppositely located leg portion 22c having a throughgoing bore hole 22d provided with a lateral opening 22e. The yoke 22 is inserted into slots 14d and 14d&#39; of the flat head 14 and a pin 23 is pushed into the bore 22b. The coupling pin 16 is pushed through the opening 22d and the leg portion 22c resiliently snaps into the groove 16c of the pin 16 to thus immobilize the latter in the bore 14c of the flat head 14a. 
     Turning to FIG. 7a, in the embodiment illustrated therein, the shank 16a of a coupling pin 16&#39; is provided with a radial bore 16d having an inner thread into which there is threaded a screw 23. As shown in FIG. 7b, the screw 23 is provided with a blind bore 23a in which there is held an arresting pin 231, which, with its rounded end, projects beyond the radial end face of the screw 23. The other, flat opposite end of the arresting pin 23b is, with the intermediary of a spring 23c, supported on a bottom face of the bore 23a. As illustrated in FIGS. 7c, 7d and 7e, the flat head 14a has a radial bore 14e which communicates with and is transverse to, the flat head bore 14c. When the coupling pin 16&#39; is to be removed from the flat head 14a, first the arresting pin 23 is pushed in by a simple tool, for example, by a small bar or nail introduced through the bore 14e, to be in a withdrawn position relative to the bore 14e, so that the securing bolt 16 may be pulled out of the bore 14c. 
     Turning to FIG. 8, in the embodiment illustrated therein, a coupling pin 16&#34; which has at its free end a slot 16e defining an enlarged forked construction formed of tines 16f and 16g, having an outwardly projecting enlargement 16h and 16i, respectively. The tines 16f and 16g are elastic so that they can expand (latch) into the slot 14d provided in the flat head 14a. 
     FIG. 9 illustrates a modification of the embodiment of FIG. 8, wherein the tines 16f&#39; and 16g&#39; of a coupling pin 16&#39;&#34; are pressable outwardly by means of a screw 24 which is positioned along an axial inner bore 16k having an inner thread 16m. The tines 16f&#39; and 16g&#39; are thus pressed against the inner wall of the bore 14c, so that the coupling pin 16&#39;&#34; is firmly anchored. The inner bore 14c is cylindrical and an anchoring of the coupling pin 16&#39;&#34; is effected by friction. To ensure a form-fitting relationship between tines and bore wall, the bore 14c may conically slightly widen from the end face of the flat head 14a inwardly. 
     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.