Cleaning device for traveling flats of a carding machine

A carding machine includes flat bars traveling in an endless path. First and second end rolls periodically reverse the travel direction of each flat bar. First and second drive shafts carry and rotate the respective first and second end rolls. An apparatus for cleaning the flat bars includes a throughgoing, eccentric aperture provided in a radial wall of the first end roll. At any time at least two mutually adjoining flat bars, situated on the first end roll, are aligned at least partially with the aperture. A suction inlet adjoins the radial wall of the first end roll for being periodically brought into alignment with the aperture as the first end roll rotates. A suction chamber is formed by a space bounded by the adjoining flat bars and a surface of the first drive shaft.

This application claims the priority of German Application No. 199 63 082.8
 filed Dec. 24, 1999, which is incorporated herein by reference.
 BACKGROUND OF THE INVENTION
 This invention relates to a device for cleaning traveling flat bars
 circulating in a carding machine. The flat bars are mounted on an endless
 carrier supported on end sprockets which periodically reverse the
 direction of travel of the flat bars. At least at one region of reversal a
 chamber-like suction device is arranged which is coupled to a suction
 source and has a suction opening.
 In a known apparatus, as described in European Patent No. 0 366 948, to
 which corresponds U.S. Pat. No. 4,945,609, at one location of reversal,
 coaxially with the center of curvature, an elongated suction pipe is
 provided which is situated between the two end sprockets and extends along
 the width of the carding machine, that is, along the length of the
 traveling flats. At one end face the suction pipe terminates in a flange
 to be coupled to a suction source. A suction slot is provided in the
 suction pipe along the entire length thereof.
 The above-outlined prior art construction has the following disadvantages:
 The sole suction slot has only a slight suction effect. Further, the
 suction pipe is an additional structural component which is difficult to
 install in the zone of reversal where the sprocket drive shaft is
 positioned, thus rendering the apparatus complex and expensive. To avoid
 undesired air flows and to reduce the air consumption, additional measures
 are required such as the provision of sealing lips mounted on the back of
 the flat bars for sliding on the suction pipe. Also, the coupling to the
 suction source must be guided around the traveling flats sprockets.
 SUMMARY OF THE INVENTION
 It is an object of the invention to provide an improved apparatus of the
 above-outlined type from which the discussed disadvantages are eliminated
 and which, in particular, is simple to construct and assemble and results
 in a better cleaning efficiency.
 This object and others to become apparent as the specification progresses,
 are accomplished by the invention, according to which, briefly stated, the
 carding machine includes a traveling flats assembly which has a plurality
 of flat bars traveling in an endless path. The flat bars are spaced from
 one another in a travel direction thereof. First and second end rolls
 periodically reverse the travel direction of each flat bar. At any time a
 plurality of flat bars are situated in a circular array on each end roll
 for being carried in a circular path thereby. First and second drive
 shafts carry and rotate the respective first and second end rolls. An
 apparatus for cleaning the flat bars is arranged in a region of at least
 the first end roll. The apparatus includes a throughgoing, eccentric
 aperture provided in a radial wall of the first end roll. At any time at
 least two mutually adjoining flat bars, situated on the first end roll,
 are aligned at least partially with the aperture. A suction inlet adjoins
 the radial wall of the first end roll for being periodically brought into
 alignment with the throughgoing aperture upon rotation of the first end
 roll. A suction chamber is formed by a space bounded by the adjoining flat
 bars and a peripheral surface of the first drive shaft.
 By providing a vacuum chamber formed by adjoining outer surfaces of the
 flat bars and the drive shaft, that is, already existing structural
 elements are being utilized, the structural and mounting outlay is
 significantly reduced as compared to prior art arrangements. A suction
 chamber provided in this manner has a small cross section whereby a higher
 flow velocity is achieved which, in turn, leads to an increased cleaning
 effect. The suction source may be arranged without spatial problems at the
 outer side of the end sprocket and may draw air in this manner through the
 suction openings. Further, advantageously, the tooth gaps of the end
 sprocket may be exposed to a suction stream and may thus be cleaned.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 FIG. 1 shows a carding machine CM which may be, for example, a DK 903
 high-performance carding machine manufactured by Trutzschler GmbH & Co.
 KG, Monchengladbach, Germany. The carding machine CM has a feed roll 1, a
 feed table 2 cooperating with the feed roll 1, licker-ins 3a, 3b, 3c, a
 main carding cylinder 4, a doffer 5, a stripping roll 6, crushing rolls 7,
 8, a web guiding element 9, a sliver trumpet 10, calender rolls 11, 12 and
 a traveling flats assembly 13 having slowly circulating flat bars 14 which
 move approximately at between 0.05 and 0.4 m/min. The flat bars 14 are at
 opposite longitudinal ends thereof coupled to respective, non-illustrated,
 parallel-arranged endless circulating belts trained about end rollers,
 such as end rolls (end sprockets) 13a, 13b. Also referring to FIG. 2, the
 flat bars 14 are pulled by the belts in the working direction A over
 non-illustrated bends and they reverse direction by means of the end
 sprocket 13a rotating in the direction D and continue their travel in the
 idling direction B. Then the end sprocket 13b, rotating in the direction C
 once again advances the flat bars 14 in the working direction A. The
 direction of rotation of the rolls of the carding machine are shown by
 curved arrows drawn therein. At the outlet of the carding machine CM a
 sliver coiler 16 is positioned for depositing sliver into the coiler can
 16'. On the return travel side the flat bars 14, as they move in the
 idling direction B, are exposed to slowly rotating flat bar brushes 17 for
 cleaning the flat bar clothings 14'. The flat bar brush 17 cooperates with
 a rapidly rotating cleaning roll 18. A suction device 19 draws debris,
 dust, short fibers and the like from the inner space underneath the cover
 20 of the card.
 According to FIG. 2 the frontal sprocket 13b (as well as the
 non-illustrated other frontal sprocket supporting the other belt connected
 with the respective opposite longitudinal ends of the flat bars 14) has
 five circumferentially distributed throughgoing elongated openings 21. On
 the outer circumferential surface of the drive shaft 22 a yielding
 cylindrical jacket 23 (made, for example, of foam material) is arranged.
 The outer surface of the jacket 23 is in airtight engagement with the back
 face 14" of those flat bars 14 which, during the course of their travel,
 are situated on the sprocket 13b. By virtue of this arrangement, the
 suction chamber between two adjoining flat bars 14 has narrow limits and
 has a small volume.
 FIG. 3 shows the same arrangement for the rear belt sprocket 13a and is
 duplicated for the other, non-illustrated rear belt sprocket at the
 opposite end of the flat bars. As also shown in FIG. 4, the inlet opening
 of a suction pipe 25 is located close to the outer face (radial wall) of
 the sprocket and is aligned with the elongated openings 21 as they pass
 by. The inlet opening of the suction pipe 25 is situated in the region
 where the direction of travel of the flats is reversed and draws air
 through the sprocket 13a of the traveling flats drive. Thus, as it may
 also be observed in FIG. 2, the suction chamber 15.sub.1 is composed by
 two adjoining flats bars 14.sub.1 which at least partially extend within
 the outline of the inlet opening of the suction pipe 25 and the jacket 23
 surrounding the sprocket drive shaft 22. Since the locations of suction
 have a small cross section, a high flow velocity is obtained. As the end
 sprocket rotates, the location of suction is closed in the intermediate
 traveling bar space and thus the soiled sprocket tooth gaps are exposed to
 suction. A suction nipple 25 is coupled to a non-illustrated suction
 source. An adjustable setting flange 26 is affixed to the suction nipple
 25 and is mounted on the frame of the carding machine.
 Particularly referring to FIGS. 2, 3 and 4, the suction nipple 25 of the
 suction source immediately adjoins the outer side of the end sprocket 13a.
 The suction chambers 15.sub.1, 15.sub.2 are formed essentially by the
 drive shaft 22 and the space between the outer faces of any two adjoining
 flat bars 14.sub.1 which are simultaneously at least partially within the
 outline of an opening 21 and, at the same time, are located within the
 outline of the suction nipple 25.
 Thus, as the end sprocket 13a and/or 13b associated with a suction
 arrangement according to the invention rotate, consecutively different
 suction chambers 15.sub.1 arrive into the region of the suction nipple 25
 whereby the dust laden air (arrow E in FIG. 4) is drawn from the suction
 chamber 15.sub.1 (see FIG. 3) through the elongated end sprocket opening
 21 into the suction nipple 25. FIG. 3 furthermore shows that the tooth
 gaps 24 between the teeth of the end sprocket are also exposed to suction
 and are thus cleaned.
 By virtue of the non-continuous mode of operation, a vacuum fluctuation is
 obtained. This prevents, among others, an adherence or winding of the
 fibers on the structural components such as the sprockets 13a and/or 13b,
 the flat bars 14 and the flat bar drive belts.
 FIG. 5 shows in perspective view one end sprocket 13b according to the
 invention to more clearly illustrate the tooth gaps 24 between adjoining
 sprocket teeth and the five elongated suction apertures 21. The drive
 shaft not shown in FIG. 5 is adapted to pass through the central sprocket
 opening 27.
 The suction may take place bilaterally on the right and left-hand side of
 the machine or may be effected only at a single machine side. Preferably
 such a suction is effected from the left-hand machine side since there the
 drive need not be circumvented. In case of a bilateral suction structure,
 in the middle of the suction chamber normally a dead spot would be formed
 which, however, is eliminated due to the fluctuating suction according to
 the invention. In case of unilateral suction on the other side, the
 suction stream may advantageously be enhanced by air pressure pulses in
 which case the component 25 is, at such other side, functioning as a
 pneumatic pressure outlet.
 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.