The present invention concerns a web take-off apparatus at the doffer of a card with a pair of delivery rolls forming a nip line for the web, arranged after the doffer roll, which at each delivery roll is provided with a stationary grazing blade, set closely to the cylindrical surface, for seed particles and siπtilar impurities.

Using-web take-off devices of the above mentioned type, as known e.g. from German Patent Application DT-AS 1.292.550 or Russian Patent SU-PS 212.107, impurities stemming from the fibre material, such as e.g. seed particles or similar impurities, which upon delivery of the web from the nip line of the delivery rolls adhere to the delivery rolls, can be eliminated by the scraping or grazing blade from the cylin- drical surface of the delivery rolls. However, it is not prevented that the web emerging sticks to the one or to the other delivery roll and is carried on thereon, in such manner that the web can be torn.

it thus is the object of the present invention to create a web take-off apparatus at the doffer of a card, using which disadvantages of the devices of such type known thus far can be eliminated and using which tearing of the web is to be avoided and impurities sticking to the delivery rolls are to

be eliminated.

For achieving this object the web take-off apparatus of th type mentioned initially is characterised in that a web deflector is set to at least one delivery roll between the nip line and the grazing blade and outside of, but in the vicinity of, the normal, predetermined free web exit path a distance of at least 0.1 mm.

In the web take-off apparatus according to the invention b the combination of web deflector and grazing blade Separ¬ ation is achieved of the web if for any reason it adheres the delivery roll upon leaving the nip line and adheres to the impurities sticking to the cylinder surface, in which process the impurities remaining on the delivery roll are eliminated mechanically subsequently only by the closely s grazing blade. Thus, cleaning of the delivery roll is effected, the deflection or Separation of the web and sub¬ sequently the grazing of impurities being effected in seq- uence, i.e. the cleaning Operation is effected in two sub- sequent but separated cleaning Steps.

By suitable arrangement of the web deflecting device the w possibly carried on can be brought back in an advantageous manner already in the vicinity of the normal, free web exi path, e.g. to a condensβr with subsequent take-off rolls, onto the normal path. If the web deflecting device is pro vided e.g. on both delivery rolls, Separation of a web carried on by either the delivery roll located above the n line or by the one located below the nip line from the rol and from the impurities on the rolls is ensured.

The web take-off apparatus according to the invention func- tions in particularly advantageous manner, if one of the delivery rolls is designed as a crush roll which can be pressed against the other delivery roll, as in this case the web can be separated from the crushed, sticky seed particles adhering to the roll surfaces due to the crushing pressure, particularly if a fibre material of high trash content is processed into a web, in which case web breakages due to uncontrolled tearing of web portions thus can be avoided. Advantageously, e.g. the web deflecting device thus extends in the direction of the longitudinal axis of the delivery roll over a working zone, in which manner uniform deflection and Separation back to the normal path can be effected on the deflecting blade. The clearance between the web de- flecting device and the delivery roll is chosen such, that reliable and uniform deflection and Separation of the web from the deliver roll can be ensured, and is chosen accord¬ ing, e.g. the thickness of the web and/or according to the size of the impurities or particles, and can be chosen in the ränge of 0.1 to 0.4 mm preferably or larger.

The web deflector can be a rotatably supported deflecting roll, which is driven in the same direction as the delivery roll, and which e.g. made of steel, is provided with a surface providing a better grip on the web, e.g. by a coat ensuring the desired grip or by a suitably knurled or fluted surface. Also, however, a web deflecting blade extending in the direction of the longitudinal axis of the delivery roll can be provided, which is arranged inclined against the direction of rotation of the delivery roll.

The invention is described in more detail in the following with reference to illustrated design examples. It is shown in:

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Fig. 1 a schematic section of a part of a card with a web take-off apparatus,

Fig. 2 a view of a part of Fig. 1 as seen in the direc- tion of arrow II,

Fig. 3 a design example of a part of the web take-off apparatus according to Fig. 1, show schematical in a section,

Fig. 4 another design example of a part of the web take off apparatus according to Fig. 1, shown schemat cally in a section,

Fig. 5 a web deflecting roll shown in a cross-section,

Fig. 6 a view of another web deflecting roll,

Fig. 7 a further design example of a part of the web take-off apparatus according to Fig. 1, shown schematically in a cross-section,

Fig. 8 a view of a part of Fig. 7 as seen in the direct of arrow VIII, and

Fig. 9 another embodiment of a part of Fig. 1, shown schematically in a cross-section.

In a card frame 1 with a cover 2 a main drum 5 provided wi a clothing 4 and drivable in the direction of rotation A, doffer roll 7 provided with a clothing 6 and drivable in t direction of rotation B and a pair of delivery rollers 8, drivable in opposite directions of rotation C and C. respe ively, are rotatably supported in frame walls 3 arranged o both sides of the machine (one wall only being shown) . Th

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drive mechanisms for the rolls of a card, known as such, are not shown for better clarity also in the illustrations of the further design examples of the inventive apparatus. The delivery roll 8a is set so closely to the clothing points 6 of the doffer roll 1 , that a web 9 is taken over correctly. The delivery roll 8 is provided with a s ooth surface and with the delivery roll 8a also provided with a smooth sur¬ face forms a nip line K for the web 9 penetrating between the rolls 8 and 8a. Above the delivery roll 8a arranged below the nip line K a grooved roll 10, with grooves 11 extending e.g. helically, which can be driven in the direction of arrow D, is rotatably supported that it forms a nip line with the delivery roll 8a, with which it cooperates. To both delivery rolls 8 and 8a a grazing or scraping blade 12 and 12a respectively, is coordinated for grazing and eliminating impurities, each blade extending in the direction of the longitudinal axis of the corresponding delivery rolls 8 and 8a respectively, and contacting the cylindrical surface of the roll. The grazing blades 12 and 12a respectively, are arranged inclined against the direction of rotation C and C, respectively of the delivery rolls 8 and 8a respectively, and are ounted stationary and adjustably (not shown) on a frame part 14 and 14a respectively, in a support device 13 and 13a respectively.

On the web delivery side of the pair of delivery rolls 8,8a a web deflecting roll 15 is arranged, as seen in the direc¬ tion of rotation C of the delivery roll 8, between the nip line K and the grazing blade 12, in close vicinity, but at a distance of at least 0.1 mm from the delivery roll 8, which web deflecting roll 15, as shown further in Fig. 2, is rotatable about its longitudinal axis E and which can be driven in the direction of arrow F, i.e. in the sa e direc¬ tion as the delivery roll 8, and which extends in the dir- ection of the longitudinal axis G of the delivery roll 8.

_O ver a working width H, facing the delivery roll 8, which corresponds e.g. to the width of the web processed, the w deflecting roll 15 is provided with a coat 15a of syntheti material e.g. made from polyurethane, for increased grippi power, which coat, however, shows as little tendency of fibre adhesion as possible.

The web take-off apparatus now functions as follows:

The web 9 is transferred from the main drum 5 via the doff roll 7 to the pair of delivery rolls- 8, 8a and from there passes along a normal predetermined path 9a into a condens funnel 16 and subsequently is taken in by a pair of rolls 18, 18a, which are arranged in a frame part 17 and are driven in the direction of arrows L, L. and is given off a a sliver.Jf the web 9 upon leaving the nip line K between the delivery rolls 8 and 8a, e.g. sticks to the delivery roll 8, the web carried on over the path 9b indicated with broken lines in Fig. 1 into the zone of the web deflecting roll 15 located closely outside the web path 9a, is caught by the deflecting roll 15 and owing to the rotation of rol 15 is brought back to predetermined normal path 9a of the web 9 to the pair of rolls 18, 18a. The circu ferential speed of the web deflecting roll 15in this arrangement can be equal to, or exceed by, e.g. 5% to 10% the circumfer¬ ential speed of the delivery roll 8. Any impurities, such as seed particles, trash particles or similar particles, penetrate through the small gap corresponding to the dis- tance a between the cylindrical surface of the delivery ro 8 and the periphery of the web deflecting roll 15, thus ar not caught by the web deflecting roll 15 and reach the grazing blade 12, by which the impurities are scraped off from the cylindrical surface and are eliminated in the direction of arrow M by an air stream generated by a sucti device 25. In this manner the web not only is prevented

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from deviating too far from its desired normal path 9a between the pair of delivery rolls 8, 8a and the pair of rolls 18, 18a and thus is not exposed to the danger of a web breakage, but furthermore also is separated from the impurities remaining on the delivery roll 8. The grazing blade 12a in this arrange ent functions in analogous manner as the grazing blade 12, in such manner that the web 9 on the entry side of the pair of delivery rolls 8, 8a always contacts cleaned cylinder surfaces of said pair of rolls. Between the web deflecting roll 15 and the grazing blade 12, arranged subsequently, a distance preferably is chosen which precludes that impurities from the grazing blade 12 are carried on by the web deflecting roll 15.

As shown furthermore in Fig. 2, two helically extending de¬ flecting or cleaning grooves 19, 19a are provided in the delivery roll 8, which carry impurities accumulated on the grazing blade 12, as seen in the rotational direction C of the delivery roll 8, to the back of the grazing blade 12, from where they are eliminated, e.g. by a central suction (not shown) active there and provided as such on the card, in such manner that the grazing blade also is freed of jammed impurities. The cleaning grooves of the above men- tioned type also can be provided on the lower delivery roll 8a for the same reasons.

The web deflecting roll 15 (Fig. 3) is supported in a bear- ing plate 20 provided on each side, which is adjustably guided on a support rail 22, which is screw-mounted to the frame wall 3 using screws 21, in such manner that the web deflecting roll 15 can be moved towardsthe delivery roll 8. For fixing the bearing plate 20 on the frame wall 3, screws 23 are provided which for setting the distance a protrude via long bores 24 extending in the bearing plate 20 parallel

to the support rail 22.

In Fig. 4, in which the parts identical with the ones show in Fig. 1 also are designated with the sa e signs, also th web deflecting device in form of the web deflecting roll 1 is coordinated to the delivery roll 8a also, seen in its direction of rotation C, of the delivery roll 8a, between the nip line K and the grazing blade 12a, the clearance a also being at least 0.1 mm between the rolls 8a and 15, ro 15 however, being driven in the direction of arrow F^ in th same direction as the delivery roll 8a.

A web possibly clinging to the lower delivery roll 8a is caught in the same manner as described for the arrangement according to Fig. 1, by the web deflecting roll 15 and by the action of which the web is brought back up to the desired web path, whereas the impurities can reach the grazing blade 12a.

According to Fig. 5 also application of a web deflecting roll 26 provided with a fluted surface 26a and according t

Fig. 6 also a web deflecting roll 27 can be provided which over a working width H, is provided with a knurled surface

27a.

As shown furthermore in Fig. 7, wherein again parts identi cal to the ones shown in Fig. 1 are designated with the sa signs, a delivery roll 28 of a pair of delivery rolls 28, 28a is designed as a crush roll supported in slots 29 in t frame wall 3 extending towards the centre of the delivery roll 28a. Onto the bearing sleeve 30 of the delivery roll which is movable in the slots 29 a pression spring 31 acts generating the corresponding pressure acting onto the web passing the nip line between the delivery rolls 28 and 28a

In the design example according to Fig. 7, e.g. the web deflecting roll 15 advantageously is provided with a coat 15^ of synthetic material, as also if the surface of the syn- thetic coat 15ιvis smooth, the web is gripped more reliably, i.e. is carried on and brought back, as if the web deflec¬ ting roll 26 or 27 is used, such that a larger clearance a can be chosen than if rolls 26 or 27 are used, in which arrangement undesirable reduction of the clearance a and particularly any contact between the web deflecting roll 15 and the delivery roll 28 during the passage of a thick place in the web through the nip line K and the resulting dis- placement of the delivery roll 28 can be avoided. Also the application of the grooves 19, 19a (Fig. 2) is advantageous if crush rolls are used, as the strongly adhering impurities thus are more easily eliminated.

For taking care of the possible uεe of a delivery roll 28 with its longitudinal axis N arranged in a crossed or in a non-crossed position with respect to the delivery roll 28a, in an alternative embodiment (Fig. 8) the web deflecting roll 15 with its longitudinal axis E is arranged crossed with respect to the longitudinal roll axis N in such manner that in a crossed position as well as in the non-crossed position illustrated of the delivery roll 28 the same clear- ance a is maintained over the working width of the delivery roll 28. The crossed position of the web deflecting roll 15 preferably is a edium position between the non-crossed position of the delivery roll 28 according to Fig. 8 and a crossed position (not shown) of the roll 28 with respect to the delivery roll 28a.

In Fig. 9, in which also parts -identical with parts shown in Fig. 1 are designated with the same signs, as web deflecting devices a web deflecting blade 32 each are arranged at the

delivery rolls 8 and 8a, the blade edge each being set at distance b, which is at least 0.1 mm to the delivery roll and 8a respectively, the blade 32 being inclined against t direction of rotation C and C-. respectively, of the delive rolls 8 and 8a. A web possibly clinging to the delivery roll 8, or 8a respectively, is taken off by the deflecting blades 32 and the particles clinging to the delivery rolls and 8a can reach the grazing blades 12 and 12a owing to th clearance b, where they are eliminated as described with reference to the aforementioned design examples.

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