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(11) | EP 0 035 977 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
A drawing frame for webs of textile fibres provided with a rotary comb head Strecke mit einem rotierenden Kammstreckwerk für Textilfaservliese Etireuse pour nappes de fibres textiles, pourvue d'une tête peigneuse rotative |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a drawing frame for webs of textile fibres provided with a rotary comb head, including a base and a pair of counter-rotating shafts with horizontal axes supported by the base in a superimposed arrangement, each of the said two shafts rotatably driving a pair of axially-spaced comb-carrier discs provided with substantially radial slots in which are slidably engaged a circumferential series of needle-carrier bars or axial combs the ends of which engage in corresponding shaped guide tracks rigidly connected to the base, the combs associated with the two shafts defining two sets of needles intersecting in the treatment region for the web of textile fibres, the head further being provided with a cleaner device for cleaning the combs of the two sets of needles.
[0002] Drawing frames of the type indicated above have recently come into widespread use due to the fact that, compared with conventional machines provided with comb heads with intersecting needles controlled by worm screws or "augers", such as that disclosed in DE-t-920717, they have the advantage of a greater working speed, of reduced mechanical wear and of facilitating and limiting maintenance, while achieving the same quality of work typical of the conventional machines. In order to obtain these results it is absolutely necessary to ensure that the zone of operation of the rotary head of the machine and the mechanical members of the head itself, particularly the combs, are completely clean. Indeed, while in conventional machines with auger heads, cleaning of the combs is achieved directly due to the movement of the combs themselves, in machines with rotary comb heads, it is necessary to provide a cleaning device which is able to remove waste material which is deposited between the needles of the combs during working.
[0003] In machines having rotary comb heads at present in use, mechanical cleaning devices have been provided which consist, for example, of rotary brushes entrained with the combs, of rotary brushes controlled mechanically, or of rotary brushes controlled mechanically and cleaned by mechanical cleaners and suction nozzles. The devices have a series of disadvantages among which may be cited:
-difficulty of adjustment and of maintaining the adjustment over a period of time,
- wear and tear on the brushes and their respective control members,
- difficulty of access to the working zone of the rotary comb head to allow normal intervention by the operator during working,
- geometric impossibility of cleaning the combs completely due to the prevalence of a tangential effect in the relative movement between the cleaning brushes and the needles of the combs, which results in the impossibility of achieving complete removal of the waste material from the combs and compaction of material at the roots attaching the needles to the combs,
- constant removal, during working, of textile fibres which are held by the combs in the return phase and which should, instead, be returned to the web or mat of material during the working phase of the combs.
[0005] In order to achieve this object, the present invention provides a drawing frame for webs of textile fibres, characterised in that the cleaner device for the rotary comb head comprises a source of compressed air, means for supplying the compressed air into the volume defined by each set of needles, and means for directing the compressed air between the combs of each set of needles in the form of an elongate jet directed outwardly in a substantially radial, predetermined direction so that, during the rotation of the shaft, the said jet of compressed air flows successively over the surfaces of the combs of the respective set of needles in the longitudinal direction of the needles.
[0006] Thanks to the characteristic the following important advantages are obtained:
-greater simplicity of manufacture, assembly and maintenance of the machine,
- long working life of the cleaning device due to the absence of moving mechanical parts,
- smaller bulk of the machine head and easier access to the working zone due to the fact that the active part of the cleaning device is disposed within the set of needles,
-greater functional efficiency due to the fact that the comb-cleaning phase is carried out in short time intervals, thus avoiding the removal of textile fibres taken up by the combs themselves during the working phase.
[0007] According to a preferred embodiment of the invention each jet of compressed air is directed substantially parallel to the direction of displacement of the web of textile fibres to be treated and faces towards the output zone of the web. As a result of this characteristic, the web of textile fibres at the inlet to the rotary comb head is not disturbed by the jet of compressed air of the cleaning device.
[0008] Preferably the jets of compressed air extend parallel to the axes of the respective shafts of the head over a length substantially equal to the length of the parts of combs lying between the said comb-carrier discs. Thus the jets of compressed air act uniformly along the entire active part of each comb.
[0009] According to a further characteristic of the invention, the means for supplying compressed air to the interior of each set of needles include valve means and programmable timer means for controlling the said valve means.
[0010] This characteristic makes it possible to regulate the operation of the cleaning device in dependence on the type of material treated by the machine.
[0011] According to a preferred embodiment of the invention, each of the rotary shafts of the head is hollow and has an axial passage at one end adapted to put its hollow interior into communication with the said means for supplying compressed air; the portion of each shaft between the respective comb-carrier discs supports a freely-rotatable, cylindrical, tubular casing interposed between the shaft and the combs and provided with a pair of annular, end heads provided with plain bearings in hermetically-sealed contact with the surface of the shaft; the said casing has an axial slit formed along its lateral wall and communicating with the hollow interior of the shaft through apertures formed in the wall of the said shaft; positioning means are provided for maintaining the said tubular casing, during the rotation of the shaft, in a fixed angular position in which the said axial slit is disposed in a substantially horizontal plane passing through the axis of the shaft. The said positioning means are, to advantage, constituted by a ballast weight carried by the tubular casing.
[0012] Further advantages and characteristics of the invention will become clear during the course of the detailed description which follows, with reference to the appended drawings, provided purely by way of non-limiting example, in which:
Figure 1 is a partially-sectioned, front elevational view of one part of the drawing frame according to the invention, in which the pneumatic circuit for feeding the cleaning device is also illustrated schematically,
Figure 2 is a cross-sectional view, on an enlarged scale, taken on line II-II of Figure 1, and
Figure 3 illustrates a detail of Figure 1 on an enlarged scale.
[0013] With reference to the drawings, by 10 is indicated in its entirety a rotary comb head of a drawing frame for the treatment of webs of textile fibres. The head 10 comprises essentially a pair of vertical support pillars 12 which serve to support a pair of superimposed shafts 14 for rotation about horizontal axes. The shafts 14 are rotated in opposite senses by means of a motor and a conventional transmission not shown in the drawings.
[0014] Each of the shafts 14 supports, adjacent the pillars 12, a pair of comb-carrier discs 16 provided with corresponding, circumferential sets of substantially radial slots 18. In the slots 18 of the discs 16 associated with each shaft 14 are slidably engaged a plurality of needle-carrier bars, or combs, 20 disposed parallel to the axis of the shaft 14. As shown in detail in Figure 2, each comb 20 is constituted by a support bar 22 carrying, at its outer edge, a plurality of needles 24 which are slightly inclined to the plane of the bar 22. The ends of the bar 22 of each comb 20 project outwardly of the comb-carrier discs 16 and engage slidably in corresponding shaped guide tracks 26 formed in the support pillars 12. In this manner, during rotation of the shafts 14, the combs 20 are entrained for rotation with the discs 16 and, as a result of the shaped tracks 26, are guided along partially eccentric paths with respect to the axes of the respective shafts 14. These paths, which are clearly visible in Figure 2, effect mutual approaching of the combs 20 entrained by the two shafts 14 in the zone of treatment of the web, indicated by F, and a sharp displacement of these combs away from each other on leaving the treatment zone of the web. The combs 20 carried by the two shafts 14 thus define two sets of needles which intersect in the zone of working of the head 10.
[0015] Each shaft is hollow and has an axial passage 28 at one end, shaped as a convergent-divergent venturi opening externally of the head 10. On that portion of each shaft 14 lying between the respective comb-carrier discs 16 is mounted, for free rotation, a tubular, cylindrical casing 30 interposed between the shaft 14 and the support bar 22 of the combs 20. Each casing 30 has a pair of annular heads 32 at its ends, each head bearing an annulus of thermoplastics material 34 in contact with the surface of the shaft 14. The annuli 34 constitute plain bearings for supporting the casing 30 and are, moreover, adapted to achieve hermetic sealing of the hollow interior of the casing 30 with respect to the surface of the shaft 14.
[0016] As is clearly seen in Figure 2, each casing 30 has a semi-cylindrical upper portion 36 provided along its axial edges with edge flanges 38, 39 bent outwardly and substantially aligned in a horizontal plane. The flange 38 which faces inwardly of the machine is coupled to one of the axial edges of a semi-cylindrical, lower portion 40 which completes the tubular casing 30. The lower portion 40 is considerably thicker and, hence, considerably heavier than the upper portion 36. The other axial edge of the lower portion 40 ends a short distance from the flange 39 of the upper portion 36 so as to define an axial slit 42 which extends for the entire length of the casing 30. As a result of the conformation of the casing 30 described above, the axial slit 42 is maintained constantly in a fixed angular position, in which it is disposed in a substantially horizontal plane passing through the axis of the shaft 14, by gravity, even during rotation of the shaft 14. The axial slit 42, on the basis of what has been said above, faces outwardly of the textile machine.
[0017] The hollow interior of each casing 30 communicates with the interior of the respective shaft 14 through a series of holes 44 formed in the lateral wall of the shaft 14.
[0018] As illustrated in Figure 1, the venturi-shaped outer portion 28 of the axial passage of each shaft 14 is associated with a nozzle 46 disposed so as to form an injector 48 with the passage 28. The nozzles 46 are connected to a compressed-air supply circuit indicated in its entirety by 50. The circuit 50 includes a source 52 of compressed air connected, through a monitoring valve 53, to a filter and regulator device 54 associated with a manometer 56. The filter-regulator device 54 is connected, through a non-return valve 58, to an air accumulator 60. The accumulator 60 is connected to the two nozzles 46 with the interposition of a-solenoid valve 62 controllable by means of a programmable timer 64.
[0019] Adjacent the working zone of the head 10, on the input side for the textile fibre web F, is an entrainment assembly 68. The entrainment assembly 68 includes a pair of rotary cylinders 70 associated with a pressure roller 72, and has the function of improving the control of the web of fibres F in the feed.
[0020] During operation of the head 10, the web of fibres F is fed in a substantially horizontal direction in the direction of arrow A, through the zone between the shafts 14 and the respective combs 20. The shafts 14 are rotated in the senses indicated by the arrows B and drive the combs 20 which thus move along the paths defined by the shapes of the guide tracks 26. The rotary combs 20 thus define two sets of needles which intersect in the zone of passage of the web of textile fibres F and penetrate the web F successively, effecting, in combination with a drawing assembly 100 at the outlet, a drawing action.
[0021] Simultaneously, the pneumatic circuit 50 supplies compressed air to the two nozzles 46 through the solenoid valve 62. According to the type of material to be treated, the solenoid valve 62 may be maintained constantly in an open position or may be controlled to open and close in a predetermined cycle by means of the programmable timer 64. The compressed air leaving each nozzle 46 passes through the axial passage 28 into the hollow interior of the respective shaft 14. Thanks to the conformation of the axial passages 28 and the disposition of the nozzles 46, the compressed air leaving each nozzle draws a current of air from the external environment into the interior of the respective shaft 14. The air then passes through the holes 44 in the wall of the shaft 14 and into the tubular casing 30. The air then leaves the casing 30 through the axial slit 42, thus creating an elongate, laminar jet directed radially outwardly. During the rotation of the shaft 14, the casing 30, and hence the axial slit 42, are maintained in a fixed angular position due to the presence of the ballast constituted by the lower cylindrical portion 40 of the casing. Thus the jet of air flows tangentially over the combs 20 which are located successively in correspondence with the slit 42 and detaches and separates waste material which accumulates at the base of the needles 24. An integral suction system, known per se and not illustrated in the drawings, collects this material and discharges it outside the machine.
[0022] The conformation of the axial slits 42 and their positioning with respect to the rotary combs 20 allows an efficient cleaning action to be achieved with the minimum consumption of compressed air. The consumption of air is further reduced by the presence of the injectors 48 constituted by the axial passages 28 and the respective nozzles 46. Moreover, the jets of air which, as indicated previously, are directed parallel to the direction of displacement A of the web of textile fibres F and face towards the output zone of the web, do not disturb the web of fibres F at the inlet to and at the exit from the head 10 to any extent.
1. A drawing frame for webs of textile fibres provided with a rotary comb head (10)
including a base (12) and a pair of counter-rotating shafts (14) with horizontal axes
supported by the base in a superimposed arrangement, each of the said two shafts rotatably
driving a pair of axially spaced comb carrier discs (16) provided with substantially
radial slots (18) into which are engaged, in a slidable manner, a circumferential
series of needle carrier bars or axial combs (20) the ends of which engage in corresponding
shaped guide tracks (26) rigidly connected to the base, the combs associated with
the two shafts defining two sets of needles intersecting in the treatment region for
the web of textile fibres; the head (10) being moreover provided with a cleaner device
for cleaning the combs (20) of the two sets of needles, characterised by the fact
that the cleaner device comprises a source of compressed air (52), means (46, 50)
supplying the compressed air into the volume defined by each set of needles (24),
and means (14, 30) for directing the compressed air between the combs (20) of each
set of needles (24) in the form of an elongate jet directed outwardly in a substantially
radial predetermined direction (A) so that during the rotation of the shaft (14) the
said jet of compressed air brushes successively the surfaces of the combs (20) of
the respective set of needles (24) in the longitudinal direction of the needles (24).
2. A drawing frame according to Claim 1, characterised by the fact that the jets of
compressed air are directed substantially parallel to the direction of displacement
(A) of the web (F) of textile fibres to be treated, and faces towards the output zone
of the web (F).
3. A drawing frame according to Claim 1, characterised by the fact that the jets of
compressed air extend parallel to the axes of the shafts (14) of the head (10) for
a length substantially equal to the length of the parts of the combs (20) lying between
the said comb-carrier discs (16).
4. A drawing frame according to Claim 1, characterised by the fact that the means
(46, 50) for supplying compressed air to the interior of each set of needles (24)
comprises valve means (62) and programmable timer means (64) for the control of the
said valve means (62).
5. A drawing frame according to Claims 1 to 3, characterised by the fact that each
of the rotating shafts (14) of the head (10) is hollow and has at one end an axial
passage (28) able to put into communication the hollow interior of the shaft with
the said means (46, 50) for supplying compressed air; a portion of each shaft (14)
lying between the respective comb-carrier discs (16) supporting a freely rotatable
cylindrical tubular casing (30) interposed between the shaft (14) and the combs (20)
and provided with a pair of annular end heads (32) provided with plain bearings (34)
hermetically sealed in contact with the surface of the shaft (14); the said casing
(30) having an axial slit (42) formed along its lateral wall and communicating with
the hollow interior of the shaft (14) through aperture (44) formed in the wall of
the said shaft (14); positioning means (40) being provided for maintaining, during
the rotation of the shaft (14), the said tubular casing (30) in a fixed angular position
in which the said axial slit (42) is disposed in a substantially horizontal plane
passing through the axis of the shaft (14).
6. A draw frame according to Claim 5, characterised by the fact that the said positioning
means are constituted by a ballast weight (40) carried by the tubular casing (30).
7. A drawing frame according to Claim 6, characterised by the fact that the lateral
wall of the tubular casing (30) has a substantially semi-cylindrical lower portion
(40) which extends substantially from the said axial slit (42) up to a position in
correspondence with the region of the casing (30) diametrically opposite the slit
(42), and has a weight significantly greater than that of the remaining portion (36)
of the casing (30).
8. A drawing frame according to Claim 4, characterised by the fact that the said axial
end passage (28) of each shaft (14) is shaped in the form of a convergent-divergent
venturi, and by the fact that the said means (46, 50) for supplying compressed air
includes a pair of nozzles (46) connected to the said source of supply (52) with the
interposition of a solenoid valve (62) controllable by means of a programmable timer
(64) and each associated with the axial end passage (28) of one of the shafts (14)
in such a way as to form an air injector (48).
9. A drawing frame according to Claim 4, characterised by the fact that the hermetically
sealed plain bearings (34) carried by the end heads (32) of the tubular casing (30)
are constituted by rings of thermoplastics material.
1. Etireuse pour nappes de fibres textiles qui est pourvue d'une tête peigneuse rotative
(10) comportant une base (12) et deux arbres contre-rotatifs (14) ayant des axes horizontaux
supportés par la base suivant une disposition superposée, chacun de ces deux arbres
entraînant en rotation deux disques porte-peignes axialement espacés (16) présentant
des fentes (18) pratiquement radiales dans lesquelles est engagée, de manière à pouvoir
glisser, une série circonférentielle de barres à aiguilles ou de peignes axiaux (20)
dont les extrémités s'engagent dans des pistes de guidage (26) de forme correspondante
reliées invariablement à la base, les peignes associés aux deux arbres définissant
deux ensembles ou groupes d'aiguilles qui se croisent dans la région de traitement
de la nappe de fibres textiles; la tête (10) étant, en outre, pourvue d'un dispositif
pour nettoyer les peignes (20) des deux séries d'aiguilles, caractérisée en ce que
le dispositif de nettoyage comprend une source d'air comprimé (52), des moyens (46,
50) pour diriger l'air comprimé dans le volume défini par chaque groupe d'aiguilles
(24), et des moyens (14, 30) pour diriger l'air comprimé entre les peignes (20) de
chaque groupe d'aiguilles (24) sous la forme d'un jet allongé arienté vers l'extérieur
suivant une direction prédéterminée pratiquement radiale (A), de sorte, que pendant
la rotation de l'arbre (14), ledit jet d'air comprimé brosse successivement les surfaces
des peignes (20) des groupes respectifs d'aiguilles (24), dans la direction de l'axe
longitudinal desdites aiguilles (24).
2. Etireuse selon la revendication 1, caractérisée en ce que les jets d'air comprimé
sont dirigés suivant une direction pratiquement parallèle la direction (A) du mouvement
de la nappe F de fibres textiles devant être traitées et sont orientés vers la zone
de sortie de la nappe (F).
3. Etireuse selon la revendication 1, caractérisée en ce que les jets d'air comprimé
s'étendent parallèlement aux axes des arbres (14) de la tête (10) sur une longueur
sensiblement égale à la longueur des parties des peignes (20) s'étendant entre lesdits
disques porte-peignes (16).
4. Etireuse selon la revendication 1, caractérisée en ce que les moyens (46, 50) sont
alimentés avec de l'air comprimé, l'intérieur de chaque groupe d'aiguilles (24) comprend
une valve (62) et un minuteur programmable (64) pour commander ladite valve (62).
5. Etireuse selon l'une quelconque des revendications 1 à 3, caractérisée en ce que
chacun des arbres rotatifs (14) de la tête (10) est creux et présente, à l'une de
ses extrémités, un canal axial (28) adapté à mettre en communication l'intérieur creux
dudit arbre avec lesdits moyens (46, 50) fournissant l'air comprimé; une partie de
chaque arbre (14) s'étendant entre les disques porte-peignes respectifs (16) supportant
une enveloppe tubulaire cylindrique libre en rotation (30) interposée entre l'arbre
(14) et les peignes (20) et pourvue de deux têtes d'extrémité annulaires (32) pourvues
de paliers lisses (34) formant un joint hermétique au contact_d_e la surface de l'arbre
(14), ladite enveloppe (30) présentant une fente axiale (42) formée le long de sa
paroi latérale et qui communique avec l'intérieur de l'arbre creux (14) par une ouverture
(44) formée dans la paroi dudit arbre (14); des moyens de positionnement (40) étant
prévus pour maintenir, durant la rotation de l'arbre (14), ladite enveloppe tubulaire
(30) dans une position angulaire fixe dans laquelle ladite fente axiale (42) est disposée
dans un plan pratiquement horizontal passant par l'axe de l'arbre (14).
6. Etireuse selon la revendication 5, caractérisée en ce que lesdits moyens de positionnement
sont constitués par un contrepoids (40) porté par l'enveloppe tubulaire (30).
7. Etireuse selon la revendication 6, caractérisée en ce que la paroi latérale de
l'enveloppe tubulaire (30) a une partie inférieure sensiblement semi-cylindrique (40)
qui s'étend pratiquement de ladite fente axiale (42) jusqu'à une position correspondant
avec la région de l'enveloppe (30) diamétralement opposée à la fente (42) et a un
poids sensiblement plus grand qui celui de la partie restante (36) de l'enveloppe
(30).
8. Etireuse selon la revendication 4, caractérisée en ce que ledit canal d'extrémité
axial (28) de chaque arbre (14) présente la forme d'un venturi convergent-divergent
et en ce que lesdits moyens (46, 50) qui fournissent l'air comprimé comprennent deux
buses (46) reliées à ladite source d'alimentation (52), avec interposition d'une valve
électromagnétique (62) pouvant être commandée au moyen d'un minuteur programmable
(64) et dont chacune est associée au canal d'extrémité axial (28) de l'un des arbres
(14), de façon à former un injecteur d'air (48).
9. Etireuse selon la revendication 4, caractérisée en ce que les paliers lisses hermétiquement
scellés (34) portés par les têtes d'extrémité (32) de l'enveloppe tubulaire (30) sont
constitués par des bagues de matière thermoplastique.
1. Strecke mit einem rotierenden Kammstreckwerk (10) für Textilfaservliese, welches
Kammstreckwerk eine Basis (12) und ein Paar von gegeneinanderdrehenden Wellen (14)
mit horizontalen Achsen, die durch die Basis in einer überlagerten Anordnung gehalten
werden, aufweist, wobei jede der beiden Wellen ein Paar von axial einen Abstand voneinander
aufweisenden Kammträgerscheiben (16) drehend antreibt, die mit im wesentlichen radialen
Schlitzen (18) versehen sind, in die in gleitender Weise umfangsmäßig angeordnete
Reihen von Nadelträgerstangen oder axialen Kämmen (20) eingreifen, deren Enden in
korrespondierend geformte Führungsspuren (26) eingreifen, die starr mit der Basis
verbunden sind, wobei die Kämme, die den beiden Wellen zugeordnet sind, zwei Sätze
von Nadeln definieren, die sich in der Bearbeitungszone des Textilvlieses überschneiden,
und wobei das Kammstreckwerk (10) desweiteren mit einer Reinigungseinrichtung zu Reinigen
der Kämme (20) der beiden Sätze von Nadeln versehen ist, dadurch gekennzeichnet, daß
die Reinigungseinrichtung ein Quelle für komprimierte Luft (52), Mittel (46, 50),
die die komprimierte Luft in den Raum, der durch die beiden Sätze von Nadeln (24)
definiert ist, liefern, und Mittel (14, 30) zum Leiten der komprimierten Luft zwischen
die Kämme (20) jedes der Sätze von Nadeln (24) in Form eines länglichen Strahls, der
nach außen in einer im wesentlichen radialen, vorbestimmten Richtung (A) gerichtet
ist, so daß während der Drehung der Wellen (14) der Strahl komprimierter Luft aufeinanderfolgend
die Oberflächen der Kämme (20) des jeweiligen Satzes von Nadeln (24) in Längsrichtung
der Nadeln (24) überstreicht, enthält.
2. Strecke nach Anspruch 1, dadurch gekennzeichnet, daß die Strahlen komprimierter
Luft im wesentlichen parallel zu der Richtung der Bewegung (A) des Textilvlieses (F),
das zu bearbeiten ist, gerichtet sind und jeweils in Richtung auf die Ausgabezone
des Textilvlieses (F) weisen.
3. Strecke nach Anspruch 1, dadurch gekennzeichnet, daß sich die Strahlen komprimierter
Luft parallel zu den Achsen der Wellen (14) des Kammstreckwerkes (10) über eine Länge
erstrecken, die im wesentlichen gleich der Länge der Teile der Kämme (20) ist, die
zwischen den Kammträgerscheiben (16) liegen.
4. Strecke nach Anspruch 1, dadurch gekennzeichnet, daß die Mittel (46, 50) zum Zuführen
komprimierter Luft zu dem Inneren jedes Satzes von Nadeln (24) eine Ventileinrichtung
(62) und eine programmierbare Zeitsteuereinrichtung (64) zur Steuerung der Ventileinrichtung
(62) enthalten.
5. Strecke nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß jede der drehenden
Wellen (14) des Kammstreckwerkes (10) hohl ist und an ihrem einen Ende einen axialen
Durchlaß (28) hat, der in der Lage ist, das hohle Innere der Welle mit den Mitteln
(46, 50) zum Liefern komprimierter Luft zu verbinden, daß ein Abschnitt jeder Welle
(14), der zwischen den betreffenden Kammträgerscheiben (16) liegt, ein frei drehbares
zylindrisches rohrförmiges Gehäuse (30) trägt, das zwischen der Welle (14) und den
Kämmen (20) angeordnet ist und mit einem Paar von ringförmigen Endköpfen (32) versehen
ist, die mit flachen Lagern (34) ausgestattet sind, welche hermetisch unter Berührung
mit der Oberfläche der Welle (14) abgedichtet sind, daß das Gehäuse (30) einen axialen
Schlitz (42) hat, der längs seiner Seitenwand ausgebildet ist und mit dem hohlen Inneren
der Welle (14) durch eine Öffnung (44) in Verbindung steht, die in der Wandung der
Welle ausgebildet ist, und daß Positionierungsmittel (40) zum Halten des rohrförmigen
Gehäuses (30) in einer festen Winkelposition, in der der axiale Schlitz (42) in einer
im wesentlichen horizontalen Ebene, die durch die Achse der Welle (14) verläuft, während
der Drehung der Welle (14) vorgesehen sind.
6. Strecke nach Anspruch 5, dadurch gekennzeichnet, daß die Positionierungsmittel
durch ein Ballastgewicht (40) gebildet sind, das durch das rohrförmige Gehäuse (30)
getragen wird.
7. Strecke nach Anspruch 6, dadurch gekennzeichnet, daß die Seitenwand des rohrför- migen Gehäuses (30) einen im wesentlichen halbzylindrischen unteren Abschnitt
(40) hat, der sich im wesentlichen von dem axialen Schlitz (42) nach oben bis zu einer
Position in Übereinstimmung mit dem Bereich des Gehäuses (30) diametral gegenüber
dem Schlitz (42) erstreckt und ein Gewicht hat, das wesentlich größer als das des
verbleibenden Abschnitts (36) des Gehäuses (30) ist.
8. Strecke nach Anspruch 4, dadurch gekennzeichnet, daß der axiale Enddurchlaß (28)
jeder der Wellen (14) in Form eines konvergent-divergenten Venturi-Abschnitts ausgebildet
ist und daß die Mittel (46, 50) zum Liefern komprimierter Luft ein Paar von Düsen
(46) enthalten, die mit der Quelle für komprimierte Luft (52) über ein zwischengeschaltetes
Magnetventils (62) verbunden sind, das mittels der programmierbaren Zeitsteuereinrichtung
(64) steuerbar ist, wobei jede dem axialen Enddurchlaß (28) einer der Wellen (14)
in einer Weise zugeordnet ist, daß ein Luftinjektor (48) gebildet wird.
9. Strecke nach Anspruch 4, dadurch gekennzeichnet, daß die hermetisch abgedichteten
flachen Lager (34), die durch die Endköpfe (32) des rohrförmigen Gehäuses (30) getragen
werden, als Ringe aus einem thermoplastischen Material ausgebildet sind.