The present invention relates generally to open-end rotor spinning devices and more particularly to open-end spinning devices comprising a rotor housing having a forward opening, a spinning rotor defining a spinning cup supported for high speed rotation in the rotor housing, and a cover element for closing the forward opening of the housing.
Such open-end rotor spinning devices are known from various publications. By way of example, German Patent Publication DE 36 36 182 C2 describes rotor spinning devices which are fixed by their spinning box frames to the machine frame of an OE spinning machine. Each spinning box frame has a rotor housing which can be loaded by suction and in which rotates the rotor cup of a spinning rotor supported on support disks. The rotor housing, which is open to the front, is closed by a cover element during the spinning process.
In this known rotor spinning device the pivotably supported cover element also has a sliver opening device which comprises, as is customary, a sliver drawing-in cylinder, an opening roller or cylinder rotating in an opening-roller housing as well as a one-piece yarn guide conduit extending between the opening roller and the spinning rotor.
The spinning box can be opened in order to carry out maintenance work or other servicing. In this instance, the cover element is unlocked and folded down about a swivel pin located in the area of the rear of the spinning box. During the swiveling of the cover element both the drive whorl of the opening roller as well as the worm gear arranged on the end of the sliver drawing-in cylinder come out of engagement with the associated drive means, whereby the rotatable elements of the sliver opening device slow to a standstill. At the same time the braking of the spinning rotor is initiated via a lever linkage.
The position of the swivel pin of the cover element is particularly disadvantageous in this type of spinning box. The swivel pin, which is arranged relatively far behind the rotor cup, results in unfavorable geometric conditions and thereby in certain problems especially during the pivoting in of the conduit plate extension which supports the sliver guide conduit for opening into the rotor cup.
The above-described disadvantage is avoided in open-end rotor spinning devices like those known, e.g., from German Patent Publications DE 43 23 213 A1 or DE 43 04 088 A1.
German Patent Publication DE 43 23 213 A1 describes by way of example a rotor spinning device whose cover element is mounted so that it can swivel about a swivel pin aligned orthogonally to the rotor axis at a location vertically below the rotor opening. The swivel pin about which the cover element can be pivoted is preferably formed by short bolts which are arranged in arms or brackets forwardly projecting from the wall of the spinning box frame and over which extend fastening lugs with slot-like recesses facing rearwardly from the cover element. The bolts are fixed in these recesses by securing means which can be unscrewed.
Thus, the pivotable cover element can be removed as an entire unit after loosening of the securing means. The arrangement of the swivel pin approximately vertically below the rotor opening results in a very small vertical offset to be taken into account during the pivoting in of the conduit plate extension and enables the mouth area of the sliver guide conduit to be placed very close to the sliver sliding wall of the rotor, which has a very positive effect on the spinning result. However, this known device has the disadvantage that the securing means arranged in the area of the swivel pin of the cover element can hardly be accessed or accessed only with very great difficulty in the case of spinning devices built into the textile machine.
The rotor spinning device according to German Patent Publication DE 43 04 088 A1 describes a rotor spinning device with a removable cover element which is detachably held via a fork-like holding fixture on a correspondingly formed support fixed to the wall of the spinning box frame. The cover element rests in the area of the drive shaft for the sliver drawing-in cylinder which extends the length of the machine and, thus, the cover element can be taken off transversely to its swivel pin without any securing elements or the like having to be loosened beforehand. However, the danger in such an embodiment that the folded-up cover element may come loose inadvertently from its support can not be entirely excluded.
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