WO1979000659A1 - Spinning rotor made from steel for open end spinning machines - Google Patents

Spinning rotor made from steel for open end spinning machines Download PDF

Info

Publication number
WO1979000659A1
WO1979000659A1 PCT/EP1979/000005 EP7900005W WO7900659A1 WO 1979000659 A1 WO1979000659 A1 WO 1979000659A1 EP 7900005 W EP7900005 W EP 7900005W WO 7900659 A1 WO7900659 A1 WO 7900659A1
Authority
WO
WIPO (PCT)
Prior art keywords
spinning
zone
rotor
hardened
spinning rotor
Prior art date
Application number
PCT/EP1979/000005
Other languages
German (de)
French (fr)
Inventor
G Stahli
F Goebe
H Stalder
Original Assignee
Rieter Ag Maschf
G Stahli
F Goebe
H Stalder
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rieter Ag Maschf, G Stahli, F Goebe, H Stalder filed Critical Rieter Ag Maschf
Priority to BR7906846A priority Critical patent/BR7906846A/en
Priority to DE792936565A priority patent/DE2936565A1/en
Publication of WO1979000659A1 publication Critical patent/WO1979000659A1/en

Links

Classifications

    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01H—SPINNING OR TWISTING
    • D01H4/00—Open-end spinning machines or arrangements for imparting twist to independently moving fibres separated from slivers; Piecing arrangements therefor; Covering endless core threads with fibres by open-end spinning techniques
    • D01H4/04—Open-end spinning machines or arrangements for imparting twist to independently moving fibres separated from slivers; Piecing arrangements therefor; Covering endless core threads with fibres by open-end spinning techniques imparting twist by contact of fibres with a running surface
    • D01H4/08—Rotor spinning, i.e. the running surface being provided by a rotor
    • D01H4/10—Rotors

Definitions

  • the present invention concerns a spinning rotor made from steel for open end spinning machines for spinning staple fibers with a thinwalled rotor wall provided with a fiber collecting groove at a largest inside diameter of the spinning rotor.
  • the unhardened steel processed into the shape of the rotor body does not show the properties re ⁇ quired for preventing wear of the fiber collecting groove. Due to the high centrifugal forces the steel is worn out in the fiber collecting groove by eg foreign matter present in the fiber aterial, such as eg quartz particles in natural fiber material, or abrasive substances in man-made fibers, such as egtitan oxides. Thus the rotor wall can be weakened pre aturely which can result in bursting of the rotor wall and thus can cause damage to the machine. Progressive wear caus mainly a change of the geometry of the fiber collecting gro predetermined for spinning desired yarn type, over the life of the rotor, and thus impairs the yarn quality.
  • Spinning rotors made from unhardened steel thus have not been used in practical production of open end yarns thus far. Rather spinning rotors made from aluminum are in use, the useful life span of which is about 5,000 hours of operation, or spinning rotors provided with wear-reducing coat the life span of which, however is increased to erely abou 10 ' 000 hours of operation.
  • Application of the known spinnin rotors thus necessitates exchange of the rotors on the bearings which are not yet worn out, as their life span exceeds the one of the spinning rotors.
  • the object is achieved in that the rotor wall made from un-hardened steel is hardened in a locally limited zone maintaining the fiber collecting groove.
  • a wear resistance of the fiber collecting groove is achieved, which excludes function-impairing wear of the groove over a period correspönding to about the rotor bearing life span, which in rotors as operated practically at eg 45,000 rpm presently can cover 40,000 operating hours.
  • the predefined geometrical form required for spinning a desired yarn is aintained over this ti e span.
  • the inventive spinning rotor which with respect to the specific weight of steel is designed with a thin rotor wall, thus not only presents the advantages of the strength of the steel as such, but also presents at its largest inside diameter, ie in the zone, which in the spinning process is subject to maximum wear, a wear resistance, which in other spinning rotors cannot be achieved eg by expensive and complicated coating of the wall; if such coats are worn off at one ' place, the whole rotor becomes unusable immediately due to pitting wear and is to be replaced prematurely with respect to the rotor bearing.
  • the inventive spinning rotor provides a live span correspönding to the useful ife span of the rotor bearings as applied today, and which thus is about 5 to 10 times longer than in the spinning rotors used thus far.
  • the bearing and the rotor rather can be ordered as a balanced unit from the manufacturer and can be mounted as replacement of anjunit with worn out bearings, without necessity of sending it back to the manufacturer for replacing a worn rotor and re-balancing the completed unit.
  • Anunit with the inventive spinning rotor can be discarded by the spinner if the bearing is wor out, as the differe tial in the further life-span of the rot and the bearing is too small to justify an exchange of one of these elements economically.
  • the spinning rotor thus can be manufactured from the unhardened steel to its desired shape for use on t open end spinning machine and, after possibly correcting it for roundness, i.e. balancing, in its final geometric shape then can be hardened in the rotor wall zone containing the fiber collecting surface at the largest inside diameter, in which process the finished shape is maintained ow / ing to th partial hardening.
  • the hardened metal structure presenting the wear-resistance desired but not influencing the geometrical shape of the ro
  • the hardened zone e.g. located in the rotor wall, manufactured from one piece, between unhardened zones and / or the rotor wall zones adjacent to it can be of uniform wall thickness in such manner that uniform heat transport during the hardening process and thus uniform har ing without rotor deformation can be achieved.
  • the hardened zone or the spinning rotor can be coated inside and / or outside by rust-proofing medium, which does not i pair the fiber mater during the spinning process, e.g. can be zine-coated.
  • Fig. 2 a part of the spinning rotor according to the portion A of Fig. 1 shown enlarged, and in
  • FIG. 3 another spinning rotor made from steel for an open end spinning machine shown schematically in a section.
  • a spinning rotor 1 made from an unhardened steel la for an. open end spinning machine comprises a base body 2 and a rotor wall 3, which inside the spinning rot ⁇ r 1 is provided with a V-shaped fiber collecting groove 4 with an aperture angle ⁇ C of about 30 to 130 degrees, formed by two legs 5 and 5a intersecting at a largest inside diameter B of the spinning rotor 1 under the angle ⁇ .
  • the leg 5a With the leg 5a the rotor wall 3 on one hand side for sa botto wall together with the base body 2 and on the other hand side with the free end of the leg 5 forms a ri 7 of the spinning rotor, which is open on one side.
  • the spinning rotor 1 is coaxially mounted onto a shaft 8, by which it is set into rotation.
  • the rotor wall 3 is designed for the rotational speeds of the spinning rotor, which as a rule exceed 40,000 rpm, thin walled and with a uniform and constant wall thickness a in both legs 5 and 5a, according to the strength required and to the steel type used eg in the
  • ⁇ '"" YT r ength of 1 to 2 mm, preferentially 1.5 mm.
  • the spinning rot can be manufactured by machining from a solid piece on a lathe, or by transforming, such as eg compressing, flow-pressing. stamping or similar processes.
  • a rotor body, known as such formed from steel sheet metal, of constant w thickness of the rotor bottom wall and the rotor wall can ba applied, which is mounted onto / base body rigidly connected the shaft 8.
  • t rotor wall 3 is hardened over the whole circumference arid o the whole cross-section a, in such manner that a hardened metal structure ring with a V-shaped rotation surface C containing the fiber collecting groove 4 is formed.
  • the zone 11 bet ween the zones 12 and 12a consisting of unhardened steel extends over the groove bottom 4binto both legs 5 and 5a ov a length of the rotor wall 3 indicated by D, ie with a ri width, which is s aller than the total length of the rotor wall 3 from the rotor rim 7 to the base body 2, in such man that the fiber collecting groove 4 covered by the fiber rin is located within the hardened zone 11 (Fig. 2).
  • the width the ring preferentially is chosen such, that it exceeds zon of wall surfaces 4a immediately adjacent to the groove botto and covered by the fiber material, ie that it exceeds at ness E of the fiber ring 9.
  • the thicknes and the groove radius R are related. Between the zone 11, pr ferentially containing a hardened metal structure 11a, and zones 12 and 12a each containing an unhardened metal structure la, a confined metal structure transition zone 13 is present, depending on the temperature curve in the steel material during the hardening process.
  • the zone ll'extending over the whole circumference as a harde be ned metal structure ring can / produced by inductive hardening; owing to the steep * temperature gradient in the zones outside a sharply limited electrical field well defined transition zones 13 are produced, which eg in a ground cross-section are clearly visible, as well known, by the naked eye.
  • Inductive hardening can be effected using ajcompletely closed, but not overlapping, induction coil, which is placed around the portion of the rotor 1 to be hardened, eg around the outer circumference of the rotor 1, in such manner that the zone 11 is treated seamlessly, ie without interruptionbr overlapping.
  • the partial hardening of the rotor wall 3 in the zone 11 can be effected eg depending on the type of steel, the wall thickness a, the desired width D of the zone 11, using corre ⁇ spöndingly adapted intensities eg of the high frequency (HF ) or medium frequency (MF) induction hardening within short ti e.
  • HF high frequency
  • MF medium frequency
  • hardened zones can be produced in which the hardened metal structure extends in each leg 5 and 5a from the inside diameter B over a length F of up to 3 mm, whereas using a MF-hardening process eachleg 5 and 5a can be hardened over a length F in the rlinde of 3 to 10 mm from the inside diamond B.
  • Hardening of the metal structure also can be effected by electron beam, laser bea, or flame hardening processes.
  • the hardening over a desired length F, and thus a desired ring width D thus can be achieved from the outside or from the inside of the rotor, in which later case the hardening also can be effected over a part of the rotor wall thickness.
  • steel type preferably a flame hardening steel is used.
  • steel types are suitable which are specified by the ISO standard 683 / XII-1972, such as e.g. a Cf45 or a Cf53 steel, or a steel type as specified by the DIN standard No. 17,212, such as e.g. a Cf70 or a 49CrMo4-steel.
  • a spinning rotor 14 from unharden steel 14a for an open end spinning machine with a base body 15 is carri on, and rotated by a shaft 16.
  • Its rotor wall 17 is of constant v / all thickness, ie of constant cross-section b, whi in a horizontal bottom wall portion 18 is adjacent to the ba body 15, and which is provided with a short leg 19 angled of from there to the outside, and which meets leg 19a angled in the direction of the spinning rotor 14 towards the inside.
  • a the meeting point of the legs 19 and 19a again a largest ins diameter G of the spinning rotor 14 is present, at which a fiber collecting groove 20 with an acute aperture angle $ is provided.
  • the rotor wall is partially hardened in the zone where the legs 19 and 19a meet, in such 'manner that aga a locall limited, hardened zone 21 is provided, adjacent to which wall portions of the rotor wall 17 made from unhardene steel 14aare provided. If required, the hardened zone 21 can extend over the v / hole length of the short leg 19 and e.g. al

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Spinning Or Twisting Of Yarns (AREA)

Abstract

A spinning rotor (1) made from steel (1a) for an open end spinning machine is provided with a thinwalled rotor wall (3) with a fibre collecting groove (4) and a locally limited, hardened zone (11) comprising the fibre collecting groove (4) at the largest inside diameter (B). Owing to the partial hardening of the rotor wall (3) high wear resistance is achieved for the fibre collecting groove (4) and the finished shape and roundness of the spinning rotor (1) made from unhardened steel (1a) for application on the open end spinning machine is maintained.

Description

Spinning rotor made from steel for open end spinning machinesSpinning rotor made from steel for open end spinning machines
The present invention concerns a spinning rotor made from steel for open end spinning machines for spinning staple fibres with a thinwalled rotor wall provided with a fibre collecting groove at a largest inside diameter of the spinning rotor.The present invention concerns a spinning rotor made from steel for open end spinning machines for spinning staple fibers with a thinwalled rotor wall provided with a fiber collecting groove at a largest inside diameter of the spinning rotor.
In the open end spinning process , as known , opened fibres fed into the spinning rotor are deposited in the fibre collecting groove in the form of a fibre ring , the spinning rotor s rotat- ing at very high rotation speeds for achieving economic pro- duction , in such manner that the spinning rotor s are subject to very high centrifugal forces . In the known spinning rotors of the type described initially (comp . e . g . DE-OS 2 ' 504 ' 401) after manufacturing from steel and adjust ent to the round- ness required a finished rotor body for use on the open end spinning machine is achieved , which is of the required stab- ility against deformation under the influence of high centri¬ fugal forces . The unhardened steel processed into the shape of the rotor body, however, does not show the properties re¬ quired for preventing wear of the fibre collecting groove. Due to the high centrifugal forces the steel is worn out in the fibre collect¬ ing groove by e.g. foreign matter present in the fibre aterial, such as e.g. quartz particles in natural fibre material, or abrasive substances in man-made fibres, such as e.g.titan oxyde. Thus the rotor wall can be weakened pre aturely which can result in bursting of the rotor wall and thus can cause damage to the machine. Progressive wear caus mainly a change of the geometry of the fibre collecting gro predetermined for spinning desired yarn type, over the life of the rotor, and thus impairs the yarn quality.In the open end spinning process, as known, opened fibers fed into the spinning rotor are deposited in the fiber collecting groove in the form of a fiber ring, the spinning rotor s rotating at very high rotation speeds for achieving economic production , in such manner that the spinning rotor s are subject to very high centrifugal forces. In the known spinning rotors of the type described initially (comp. E. G. DE-OS 2 '504' 401) after manufacturing from steel and adjust ent to the round- ness required a finished rotor body for use on the open end spinning machine is achieved, which is of the required stab- ility against deformation under the influence of high centrifuge forces. The unhardened steel processed into the shape of the rotor body, however, does not show the properties re¬ quired for preventing wear of the fiber collecting groove. Due to the high centrifugal forces the steel is worn out in the fiber collecting groove by eg foreign matter present in the fiber aterial, such as eg quartz particles in natural fiber material, or abrasive substances in man-made fibers, such as egtitan oxides. Thus the rotor wall can be weakened pre aturely which can result in bursting of the rotor wall and thus can cause damage to the machine. Progressive wear caus mainly a change of the geometry of the fiber collecting gro predetermined for spinning desired yarn type, over the life of the rotor, and thus impairs the yarn quality.
Spinning rotors made from unhardened steel thus have not been used in practical production of open end yarns thus far. Rather spinning rotors made from aluminium are in use, the useful life span of which is about 5'000 hours of ope- ration, or spinning rotors provided with wear-reducing coat the life span of which, however is increased to erely abou 10' 000 hours of Operation. Application of the known spinnin rotors thus necessitates exchange of the rotors on the bearings which are not yet worn out, as their life span exceeds the one of the spinning rotors.Spinning rotors made from unhardened steel thus have not been used in practical production of open end yarns thus far. Rather spinning rotors made from aluminum are in use, the useful life span of which is about 5,000 hours of operation, or spinning rotors provided with wear-reducing coat the life span of which, however is increased to erely abou 10 ' 000 hours of operation. Application of the known spinnin rotors thus necessitates exchange of the rotors on the bearings which are not yet worn out, as their life span exceeds the one of the spinning rotors.
As.indicated in the DE-OS 2 '551'045, application of a harde steel insert in a base body of the spinning rotor for preve ting wear shows the disadvantage that the insert, made firs from unhardened, steel, after hardening of the steel body cannot be mounted in the base body without further machinin which is due, as well known, to a deformation of the steel, i.e. of the geometrical form of the insert under the tempe- rature stress during the hardening process.As.indicated in the DE-OS 2 '551'045, application of a harde steel insert in a base body of the spinning rotor for preve ting wear shows the disadvantage that the insert, made firs from unhardened, steel, after hardening of the steel body cannot be mounted in the base body without further machinin which is due, as well known, to a deformation of the steel, ie of the geometrical form of the insert under the temperature stress during the hardening process.
It thus is the object of the present invention to create a spinning rotor made from steel for an open end spinning machine of the type mentioned initially, which eli inates the disadvantage of the spinning rotors known thus far, and in which, notwithstanding the manufacture from unhardened steel, a fibre collecting groove resisting wear in spinning of fibres is provided, and in which the geometrical form of the fibre collecting surface is to be maintained independent of the duration of Operation, the life span thus being in- creased. The object is achieved in that the rotor wall made from un¬ hardened steel is hardened in a locally limited zone con- taining the fibre collecting groove.It thus is the object of the present invention to create a spinning rotor made from steel for an open end spinning machine of the type mentioned initially, which eli inates the disadvantage of the spinning rotors known thus far, and in which, notwithstanding the manufacture from unhardened steel, a fiber collecting groove resisting wear in spinning of fibers is provided, and in which the geometrical form of the fiber collecting surface is to be maintained independent of the duration of Operation, the life span thus being in- creased. The object is achieved in that the rotor wall made from un-hardened steel is hardened in a locally limited zone maintaining the fiber collecting groove.
Using the inventive spinning rotor, owning to the locally limited, partial hardening of the thin rotor wall, a wear resistance of the fibre collecting groove is achieved, which excludes function-impairing wear of the groove over a period correspönding to about the rotor bearing life span, which in rotors as operated practically at e.g. 45 '000 r.p.m presently can cover 40 '000 operating hours. Thus the prede- termined geometrical form required for spinning a desired yarn is aintained over this ti e span. The inventive spinning rotor, which with respect to the specific weight of steel is designed with a thin rotor wall, thus not only presents the advantages of the strength of the steel as such, but also presents at its largest inside diameter, i.e. in the zone, which in the spinning process is subject to maximum wear, a wear resistance, which in other spinning rotors cannot be achieved e.g. by expensive and complicated coating of the wall; if such coats are worn off at one' place, the whole rotor becomes unusable immediately due to pitting wear and is to be replaced prematurely with respect to the rotor bearing. The inventive spinning rotor on the other hand, provides a live span correspönding to the useful ife span of the rotor bearings as applied today, and which thus is about 5 to 10 times longer than in the spinning rotors used thus far. Thus the necβssity of re-equipping still operable bearings with a new rotor and of re-balancing the unit con- sisting of rotor and bearing is eliminated. The bearing and the rotor rather can be ordered as a balanced unit from the manufacturer and can be mounted as replacement of anjunit with worn out bearings, without necessity of sending it back to the manufacturer for replacing a worn rotor and re-balan- cing the completed unit. Anunit with the inventive spinning rotor can be discarded by the spinner if the bearing is wor out, as the differe tial in the further life-span of the rot and the bearing is too small to justify an exchange of one of these elements economically.Using the inventive spinning rotor, owning to the locally limited, partial hardening of the thin rotor wall, a wear resistance of the fiber collecting groove is achieved, which excludes function-impairing wear of the groove over a period correspönding to about the rotor bearing life span, which in rotors as operated practically at eg 45,000 rpm presently can cover 40,000 operating hours. Thus the predefined geometrical form required for spinning a desired yarn is aintained over this ti e span. The inventive spinning rotor, which with respect to the specific weight of steel is designed with a thin rotor wall, thus not only presents the advantages of the strength of the steel as such, but also presents at its largest inside diameter, ie in the zone, which in the spinning process is subject to maximum wear, a wear resistance, which in other spinning rotors cannot be achieved eg by expensive and complicated coating of the wall; if such coats are worn off at one ' place, the whole rotor becomes unusable immediately due to pitting wear and is to be replaced prematurely with respect to the rotor bearing. The inventive spinning rotor on the other hand, provides a live span correspönding to the useful ife span of the rotor bearings as applied today, and which thus is about 5 to 10 times longer than in the spinning rotors used thus far. Thus the nec β ssity of re-equipping still operable bearings with a new rotor and of re-balancing the unit consisting of rotor and bearing is eliminated. The bearing and the rotor rather can be ordered as a balanced unit from the manufacturer and can be mounted as replacement of anjunit with worn out bearings, without necessity of sending it back to the manufacturer for replacing a worn rotor and re-balancing the completed unit. Anunit with the inventive spinning rotor can be discarded by the spinner if the bearing is wor out, as the differe tial in the further life-span of the rot and the bearing is too small to justify an exchange of one of these elements economically.
As the local hardening is limited to the zone of the fibre collecting groove, deformations' f the spinning rotor; parti cularly of the thin rotorwall, during the hardening process are avoided, which necessarily would occur, if the whole spinning rotor is hardened.As the local hardening is limited to the zone of the fiber collecting groove, deformations' f the spinning rotor; parti cularly of the thin rotorwall, during the hardening process are avoided, which necessarily would occur, if the whole spinning rotor is hardened.
The spinning rotor thus advantageously can be manufactured from the unhardened steel to its desired shape for use on t open end spinning machine and, after possibly correcting it for roundness, i.e. balancing, in its final geometric shape then can be hardened in the rotor wall zone containing the fibre collecting surface at the largest inside diameter, in which process the finished shape is maintained ow/ing to th partial hardening. In the locally limited zone merely a met structure is present which differs from the one in the zone of the spinning rotor not subject to the hardening process, the hardened metal structure presenting the wear-resistance desired but not influencing the geometrical shape of the roThe spinning rotor thus can be manufactured from the unhardened steel to its desired shape for use on t open end spinning machine and, after possibly correcting it for roundness, i.e. balancing, in its final geometric shape then can be hardened in the rotor wall zone containing the fiber collecting surface at the largest inside diameter, in which process the finished shape is maintained ow / ing to th partial hardening. In the locally limited zone merely a met structure is present which differs from the one in the zone of the spinning rotor not subject to the hardening process, the hardened metal structure presenting the wear-resistance desired but not influencing the geometrical shape of the ro
In one design example the hardened zone e.g. located in the rotor wall, manufactured from one piece, between unhardened zones and/or the rotor wall zones adjacent to it can be of uniform wall thickness in such manner that uniform heat transport during the hardening process and thus uniform har ing without rotor deformation can be achieved.In one design example the hardened zone e.g. located in the rotor wall, manufactured from one piece, between unhardened zones and / or the rotor wall zones adjacent to it can be of uniform wall thickness in such manner that uniform heat transport during the hardening process and thus uniform har ing without rotor deformation can be achieved.
In various embodiments of the invention the hardened zone or the spinning rotor can be coated inside and/or outside by rust-proofing medium, which does not i pair the fibre mater during the spinning process, e.g. can be zine-coated.In various embodiments of the invention the hardened zone or the spinning rotor can be coated inside and / or outside by rust-proofing medium, which does not i pair the fiber mater during the spinning process, e.g. can be zine-coated.
/^& / ^ &
_ - Jf-!. The present invention is described in more detail. in the following with reference to illustrated design examples. It is shown in:_ - Jf - !. The present invention is described in more detail. in the following with reference to illustrated design examples. It is shown in:
Fig. 1 a spinning rotor made from steel for an open end spinning machine shown schematically in a section,1 a spinning rotor made from steel for an open end spinning machine shown schematically in a section,
Fig. 2 a part of the spinning rotor according to the portion A of Fig. 1 shown enlarged, and inFig. 2 a part of the spinning rotor according to the portion A of Fig. 1 shown enlarged, and in
Fig. 3 another spinning rotor made from steel for an open end spinning machine shown schematically in a section.Fig. 3 another spinning rotor made from steel for an open end spinning machine shown schematically in a section.
A spinning rotor 1 made from an unhardened steel la for an . open end spinning machine comprises a base body 2 and a rotor wall 3, which inside the spinning rotόr 1 is provided with a V-shaped fibre collecting groove 4 with an aperture angle σC of about 30 to 130 degrees, formed by two legs 5 and 5a intersecting at a largest inside diameter B of the spinning rotor 1 under the angle β . With the leg 5a the rotor wall 3 on one hand side for s a botto wall together with the base body 2 and on the other hand side with the free end of the leg 5 forms a ri 7 of the spinning rotor, which is open on one side. The spinning rotor 1 is coaxially mounted onto a shaft 8, by which it is set into rotation. Into the fibre collecting groove 4 , the groove bottom 4b of which is provided with a groove radius, ranging from 0.1 to 2 mm, fibres previously opened in the spinning process are deposited a in the form of fibre ring 9 , which fibres subsequently are taken off in the form of a twisted yarn 10 (Fig. 2) . Ow/ing to the high specifdc weight of steel the rotor wall 3 is designed for the rotational speeds of the spinning rotor, which as a rule exceed 40 '000 r.p.m,thin walled and with a uniform and constant wall thickness a in both legs 5 and 5a , according to the strength required and to the steel type used e.g. in theA spinning rotor 1 made from an unhardened steel la for an. open end spinning machine comprises a base body 2 and a rotor wall 3, which inside the spinning rotόr 1 is provided with a V-shaped fiber collecting groove 4 with an aperture angle σC of about 30 to 130 degrees, formed by two legs 5 and 5a intersecting at a largest inside diameter B of the spinning rotor 1 under the angle β. With the leg 5a the rotor wall 3 on one hand side for sa botto wall together with the base body 2 and on the other hand side with the free end of the leg 5 forms a ri 7 of the spinning rotor, which is open on one side. The spinning rotor 1 is coaxially mounted onto a shaft 8, by which it is set into rotation. Into the fiber collecting groove 4, the groove bottom 4b of which is provided with a groove radius, ranging from 0.1 to 2 mm, fibers previously opened in the spinning process are deposited a in the form of fiber ring 9, which fibers subsequently are taken off in the form of a twisted yarn 10 (Fig. 2). Ow / ing to the high specifdc weight of steel the rotor wall 3 is designed for the rotational speeds of the spinning rotor, which as a rule exceed 40,000 rpm, thin walled and with a uniform and constant wall thickness a in both legs 5 and 5a, according to the strength required and to the steel type used eg in the
f CiYPlf CiYPl
\ ' "": Y-T ränge of 1 to 2 mm, preferentially 1,5 mm. The spinning rot can be manufactured by machining from a solid piece on a lathe, or by transforming, such as e.g. compressing, flow- pressing. stamping or similar processes. Also, a rotor body, known as such, formed from steel sheet metal, of constant w thickness of the rotor bottom wall and the rotor wall can b a applied, which is mounted onto/base body rigidly connected the shaft 8.\ '"" : YT r ength of 1 to 2 mm, preferentially 1.5 mm. The spinning rot can be manufactured by machining from a solid piece on a lathe, or by transforming, such as eg compressing, flow-pressing. stamping or similar processes. Also, a rotor body, known as such, formed from steel sheet metal, of constant w thickness of the rotor bottom wall and the rotor wall can ba applied, which is mounted onto / base body rigidly connected the shaft 8.
In a locally limited zone 11, in which the largest inside dia eter B w'ith the fibre collecting groove 4 is located, t rotor wall 3 is hardened over the whole circumference arid o the whole cross-section a, in such manner that a hardened metal structure ring with a V-shaped rotation surface C containing the fibre collecting groove 4 is formed. In the rotor wall 3, which is made from one piece, the zone 11 bet ween the zones 12 and 12a consisting of unhardened steel extends over the groove bottom 4binto both legs 5 and 5a ov a length of the rotor wall 3 indicated by D, i.e. with a ri width, which is s aller than the total length of the rotor wall 3 from the rotor rim 7 to the base body 2, in such man that the fibre collecting groove 4 covered by the fibre rin is located within the hardened zone 11 (Fig. 2) . The width the ring preferentially is chosen such, that it exceeds zon of wall surfaces 4a immediately adjacent to the groove botto and covered by the fibre material, i.e. that it exceeds a t ness E of the fibre ring 9. In this arrangemant the thicknes and the groove radius R are related. Between the zone 11, pr ferentially containing a hardened metal structure 11a , and zones 12 and 12a each containing an unhardened metal struc¬ ture la, a confined metal structure transition zone 13 is present, depending on the temperature curve in the steel material during the hardening process.In a locally limited zone 11, in which the largest inside dia eter B w ' ith the fiber collecting groove 4 is located, t rotor wall 3 is hardened over the whole circumference arid o the whole cross-section a, in such manner that a hardened metal structure ring with a V-shaped rotation surface C containing the fiber collecting groove 4 is formed. In the rotor wall 3, which is made from one piece, the zone 11 bet ween the zones 12 and 12a consisting of unhardened steel extends over the groove bottom 4binto both legs 5 and 5a ov a length of the rotor wall 3 indicated by D, ie with a ri width, which is s aller than the total length of the rotor wall 3 from the rotor rim 7 to the base body 2, in such man that the fiber collecting groove 4 covered by the fiber rin is located within the hardened zone 11 (Fig. 2). The width the ring preferentially is chosen such, that it exceeds zon of wall surfaces 4a immediately adjacent to the groove botto and covered by the fiber material, ie that it exceeds at ness E of the fiber ring 9. In this arrangemant the thicknes and the groove radius R are related. Between the zone 11, pr ferentially containing a hardened metal structure 11a, and zones 12 and 12a each containing an unhardened metal structure la, a confined metal structure transition zone 13 is present, depending on the temperature curve in the steel material during the hardening process.
The zone ll'extending over the whole circumference as a harde be ned metal structure ring can/produced by inductive hardening; owing to the steep*temperature gradient in the zones outside a sharply limited electrical field well defined transition zones 13 are produced, which e.g. in a ground cross-section are clearly visible, as well known, by the naked eye. Inductive hardening can be effected using ajcompletely closed, but not overlapping, induction coil, which is placed around the portion of the rotor 1 to be hardened, e.g. around the outer circumfe¬ rence of the rotor 1, in such manner that the zone 11 is treated seamlessly, i.e. without interruptionbr overlapping. The partial hardening of the rotor wall 3 in the zone 11 can be effected e.g. depending on the type of steel, the wall thickness a, the desired width D of the zone 11, using corre¬ spöndingly adapted intensities e.g. of the high frequency (HF) or medium frequency (MF) induction hardening within short ti e. Using HF-hard'ening, e.g. for a wall thickness a ranging from 1 to 2 mm, hardened zones can be produced in which the hardened metal structure extends in each leg 5 and 5a from the inside diameter B over a length F of up to 3 mm, whereas using a MF-hardening process eachleg 5 and 5a can be hardened over a length F in the ränge of 3 to 10 mm from the inside diame¬ ter B. Hardening of the metal structure, however, also can be effected by electron beam, laser bea , or flame hardening processes. Depending on the shape of the rotor and depending on the hardening process chosen, the hardening over a desired length F, and thus a desired ring width D, thus can be achieved from the outside or from the inside of the rotor, in which later case the hardening also can be effected over a part of the rotor wall thickness.The zone ll'extending over the whole circumference as a harde be ned metal structure ring can / produced by inductive hardening; owing to the steep * temperature gradient in the zones outside a sharply limited electrical field well defined transition zones 13 are produced, which eg in a ground cross-section are clearly visible, as well known, by the naked eye. Inductive hardening can be effected using ajcompletely closed, but not overlapping, induction coil, which is placed around the portion of the rotor 1 to be hardened, eg around the outer circumference of the rotor 1, in such manner that the zone 11 is treated seamlessly, ie without interruptionbr overlapping. The partial hardening of the rotor wall 3 in the zone 11 can be effected eg depending on the type of steel, the wall thickness a, the desired width D of the zone 11, using corre¬ spöndingly adapted intensities eg of the high frequency (HF ) or medium frequency (MF) induction hardening within short ti e. Using HF-hard ' ening, eg for a wall thickness a ranging from 1 to 2 mm, hardened zones can be produced in which the hardened metal structure extends in each leg 5 and 5a from the inside diameter B over a length F of up to 3 mm, whereas using a MF-hardening process eachleg 5 and 5a can be hardened over a length F in the ränge of 3 to 10 mm from the inside diamond B. Hardening of the metal structure, however, also can be effected by electron beam, laser bea, or flame hardening processes. Depending on the shape of the rotor and depending on the hardening process chosen, the hardening over a desired length F, and thus a desired ring width D, thus can be achieved from the outside or from the inside of the rotor, in which later case the hardening also can be effected over a part of the rotor wall thickness.
As to the steel type, preferably a flame hardening steel is used. For examples, steel types are suitable which are speci- fied by the ISO-standard 683/XII-1972, such as e.g. a Cf45 or a Cf53 steel, or a steel type as specified by the DIN-standard No. 17.212, such as e.g. a Cf70 or a 49CrMo4-steel.As to the steel type, preferably a flame hardening steel is used. For examples, steel types are suitable which are specified by the ISO standard 683 / XII-1972, such as e.g. a Cf45 or a Cf53 steel, or a steel type as specified by the DIN standard No. 17,212, such as e.g. a Cf70 or a 49CrMo4-steel.
"F1 Owing to the locally limited, hardened zone 11 a wear resis tance for the fibre collecting groove 4 is achieved in the otherwise unhardened rotor wall 3, which withstands the wea by fibre materials and by abrasive particles carried on by t fibre material, without requiring additional adaption of th spinning rotor 1, such as e.g. by further machining, to a desired shape or roundness."F1 Owing to the locally limited, hardened zone 11 a wear resis tance for the fiber collecting groove 4 is achieved in the otherwise unhardened rotor wall 3, which withstands the wea by fiber materials and by abrasive particles carried on by t fiber material, without requiring additional adaptation of the spinning rotor 1, such as eg by further machining, to a desired shape or roundness.
Owing to the partial hardening of the rotor wall 3/ its geo- metric shape is maintained, and merely in the zone 11 a har ned metal structure is present. Owing to the high wear resi¬ stance of the zone 11 also eventual re-processing of the ro g-roove after a certain running time can be dispensed with. Seen in a whole, the useful life of the spinning rotor is considerably prolonged by the zone 11, i.e. is prolonged to about the expected life span of the bearing at the rotationa speeds considered.Owing to the partial hardening of the rotor wall 3 / its geometric shape is maintained, and merely in the zone 11 a har ned metal structure is present. Owing to the high wear resistance of the zone 11 also eventual re-processing of the ro g-roove after a certain running time can be dispensed with. Seen in a whole, the useful life of the spinning rotor is considerably prolonged by the zone 11, ie is prolonged to about the expected life span of the bearing at the rotationa speeds considered.
In the embodi ent according to Fig. 3 a spinning rotor 14 from unharden steel 14a for an open end spinning machine with a base body 15 is carri on, and rotated by a shaft 16. Its rotor wall 17 is of con¬ stant v/all thickness, i.e. of constant cross-section b, whi in a horizontal bottom wall portion 18 is adjacent to the ba body 15, and which is provided with a short leg 19 angled of from there to the outside, and which meets leg 19a angled in the direction of the spinning rotor 14 towards the inside. A the meeting point of the legs 19 and 19a again a largest ins diameter G of the spinning rotor 14 is present, at which a fibre collecting groove 20 with an acute aperture angle $ is provided. The rotor wall is partially hardened in the zone where the legs 19 and 19a meet, in such 'manner that aga a locall limited, hardened zone 21 is provided, adjacent to which wall portions of the rotor wall 17 made from unhardene steel 14aare provided. If required, the hardened zone 21 can extend over the v/hole length of the short leg 19 and e.g. alIn the embodi ent according to Fig. 3 a spinning rotor 14 from unharden steel 14a for an open end spinning machine with a base body 15 is carri on, and rotated by a shaft 16. Its rotor wall 17 is of constant v / all thickness, ie of constant cross-section b, whi in a horizontal bottom wall portion 18 is adjacent to the ba body 15, and which is provided with a short leg 19 angled of from there to the outside, and which meets leg 19a angled in the direction of the spinning rotor 14 towards the inside. A the meeting point of the legs 19 and 19a again a largest ins diameter G of the spinning rotor 14 is present, at which a fiber collecting groove 20 with an acute aperture angle $ is provided. The rotor wall is partially hardened in the zone where the legs 19 and 19a meet, in such 'manner that aga a locall limited, hardened zone 21 is provided, adjacent to which wall portions of the rotor wall 17 made from unhardene steel 14aare provided. If required, the hardened zone 21 can extend over the v / hole length of the short leg 19 and e.g. al
• : - over a part of the bottom wall portion 18 adjacent to it. •: - over a part of the bottom wall portion 18 adjacent to it.

Claims

Claims:Claims:
Spinning rotor made from steel for open end spinning machines for spinning staple fibres, with a thin-walled rotor wall containing at a largest inside diameter of t spinning rotor a fibre collecting groove, characterized in that the rotor wall (3;17) made from unhardened stee (1 ,1a;14a) in a' locally limited zone (11,11a;21) con¬ taining the fibre collecting groove (4,4b; 20) is hardenSpinning rotor made from steel for open end spinning machines for spinning staple fibers, with a thin-walled rotor wall containing at a largest inside diameter of t spinning rotor a fiber collecting groove, characterized in that the rotor wall (3; 17) made from unhardened stee (1, 1a; 14a) in a ' locally limited zone (11,11a; 21) con¬ taining the fiber collecting groove (4,4b; 20) is harden
Spinning rotor according to claim 1, characterized in t the hardened zone (11; 21) is located between unhardened zones (12,12a) of the rotor wall (3;17) .Spinning rotor according to claim 1, characterized in t the hardened zone (11; 21) is located between unhardened zones (12,12a) of the rotor wall (3; 17).
3. Spinning rotor according to claim 1, characterized in that the locally limited zone (11;21) is hardened throu the whole cross-section (a;b) of the rotor wall (3;17) .3. Spinning rotor according to claim 1, characterized in that the locally limited zone (11; 21) is hardened throu the whole cross-section (a; b) of the rotor wall (3; 17).
4. Spinning rotor according to claim 1, characterized in . that the zone (11;21) , in which two legs (5,5a;19,19a) the rotor wall (3;17) merge at the largest inside dia¬ meter (B;G) and form the fibre collecting groove (4,4b; is hardened.4. Spinning rotor according to claim 1, characterized in. that the zone (11; 21), in which two legs (5,5a; 19,19a) the rotor wall (3; 17) merge at the largest inside dia¬ meter (B; G) and form the fiber collecting groove ( 4,4b; is hardened.
5. Spinning rotor according to claim 1 or 2, characterized in that the rotor wall (3;17) adjacent to the hardened zone (ll;2l is of a- cross-section (a;b) which remains constant.5. Spinning rotor according to claim 1 or 2, characterized in that the rotor wall (3; 17) adjacent to the hardened zone (ll; 2l is of a- cross-section (a; b) which remains constant.
6. Spinning rotor according to claim 1 or 5, characterized in that the rotor wall (3;17) in the hardened zone (11; is of a wall thickness (a;b) ranging from 1 to 2 ira.6. Spinning rotor according to claim 1 or 5, characterized in that the rotor wall (3; 17) in the hardened zone (11; is of a wall thickness (a; b) ranging from 1 to 2 ira.
7. Spinning rotor according to claim 6, characterized in t the v/all thickness (a;b) in the hardened zone (11;21) is 1,5 u 8. Spinning rotor according to claim 1, characterized in that the locally limited zone (ll :21) is structure- hardened (11a) .7. Spinning rotor according to claim 6, characterized in t the v / all thickness (a; b) in the hardened zone (11; 21) is 1.5 u 8. Spinning rotor according to claim 1, characterized in that the locally limited zone (ll: 21) is structure-hardened (11a).
5 9. Spinning rotor according to claim 1 or 8, characterized in that between the hardened zone (11;21 and the unharde¬ ned zone (12,12a ,19, 19a) of the rotor wall (3) a well defined structure transition (13) is present.5 9. Spinning rotor according to claim 1 or 8, characterized in that between the hardened zone (11; 21 and the unharded zone (12,12a, 19, 19a) of the rotor wall (3) a well defined structure transition (13) is present.
10 10. Spinning rotor according to claim 1, characterized in that the steel (la) can be flame-hardened.10. 10. Spinning rotor according to claim 1, characterized in that the steel (la) can be flame-hardened.
11. Spinning rotor according to any of the Claims 8 through11. Spinning rotor according to any of the Claims 8 through
10, characterized in that in the locally limited zone 15 (11;21) the structure (11a) is inductively hardened.10, characterized in that in the locally limited zone 15 (11; 21) the structure (11a) is inductively hardened.
12. Spinning rotor according to any of the Claims 8 through12. Spinning rotor according to any of the Claims 8 through
11, characterized in that the steel (la;14a) e.g. is a Cf45-, Cf53-, Cf70- or a 49CrMo4-steel.11, characterized in that the steel (la; 14a) e.g. is a Cf45-, Cf53-, Cf70- or a 49CrMo4-steel.
2020th
13. Spinning rotor according to claim 2, characterized in that the rotor wall (3;17) in its unhardened zones and in the hardened zone (11;21) is of the same wall thickness.13. Spinning rotor according to claim 2, characterized in that the rotor wall (3; 17) in its unhardened zones and in the hardened zone (11; 21) is of the same wall thickness.
25 14. Spinning rotor according to any of the Claims 1 through25 14. Spinning rotor according to any of the Claims 1 through
13, characterized in that the steel (la;13a ;14a) is coated with an anticorrosion agent.13, characterized in that the steel (la; 13a; 14a) is coated with an anticorrosion agent.
15. Spinning rotor according to claim 1, characterized in 30 that the hardened zone (11;21) and the unhardened zones15. Spinning rotor according to claim 1, characterized in 30 that the hardened zone (11; 21) and the unhardened zones
(12,12a ;19, 19a) are located in the rotor wall (3;17) made from one piece.(12,12a; 19, 19a) are located in the rotor wall (3; 17) made from one piece.
16. Spinning rotor according to claim 1, characterized in 35 that the hardened zone (11; 21) with a length (D) excee- ding the groove bottom (4b) of the fibre collecting groove (4) extends to immediately adjacent zones of wall surfaces (4a).16. Spinning rotor according to claim 1, characterized in 35 that the hardened zone (11; 21) with a length (D) excee- ding the groove bottom (4b) of the fiber collecting groove (4) extends to immediately adjacent zones of wall surfaces (4a).
17. Spinning rotor according to claim 1, characterized in that the locally limited zone (11;21) is provided with a V-shaped rotation surface containing the fibre collecting groove (4,4b 20) .17. Spinning rotor according to claim 1, characterized in that the locally limited zone (11; 21) is provided with a V-shaped rotation surface containing the fiber collecting groove (4,4b 20).
/ - ό -ϊ r. / - ό -ϊ r.
PCT/EP1979/000005 1978-02-24 1979-02-01 Spinning rotor made from steel for open end spinning machines WO1979000659A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BR7906846A BR7906846A (en) 1978-02-24 1979-02-01 WIRING ROTOR MADE FROM STEEL FOR OPEN END WINDING MACHINES
DE792936565A DE2936565A1 (en) 1978-02-24 1979-02-01 Spinning rotor made from steel for open end spinning machines

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH2025/78 1978-02-24
CH202578 1978-02-24

Publications (1)

Publication Number Publication Date
WO1979000659A1 true WO1979000659A1 (en) 1979-09-06

Family

ID=4224154

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1979/000005 WO1979000659A1 (en) 1978-02-24 1979-02-01 Spinning rotor made from steel for open end spinning machines

Country Status (19)

Country Link
EP (1) EP0009497A1 (en)
JP (1) JPS55500140A (en)
AR (1) AR220742A1 (en)
AT (1) AT372119B (en)
AU (1) AU529171B2 (en)
BE (1) BE874424A (en)
BR (1) BR7906846A (en)
CA (1) CA1106246A (en)
CS (1) CS220323B2 (en)
DE (1) DE2936565A1 (en)
FI (1) FI64955C (en)
GB (1) GB2036098A (en)
IL (1) IL56641A (en)
IN (1) IN151789B (en)
IT (1) IT1111526B (en)
NL (1) NL7901186A (en)
PT (1) PT69263A (en)
WO (1) WO1979000659A1 (en)
ZA (1) ZA79747B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3431944A1 (en) * 1983-09-09 1985-03-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho, Kariya, Aichi Rotor for an open-end spinning machine
US6195976B1 (en) 1999-03-09 2001-03-06 W. Schlafhorst Ag & Co. Spinning rotor for open-end spinning machines
KR20030072092A (en) * 2002-03-05 2003-09-13 장동우 Rotor for spinning frame and manufacturing method thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4441087A1 (en) † 1994-11-18 1996-05-23 Rieter Ingolstadt Spinnerei Open-end spinning device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2358479A1 (en) * 1976-07-17 1978-02-10 Schubert & Salzer Maschinen Spinning rotor for open=end spinning machine - has strong outer support with hard wearing inner segments to form spinning surface
FR2381842A1 (en) * 1977-02-25 1978-09-22 Platt Saco Lowell Ltd PERFECTED ROTOR FOR FREE FIBER SPINNING MACHINE

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5824531A (en) * 1981-08-06 1983-02-14 Sumitomo Chem Co Ltd Novel dihydric phenol derivative and its preparation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2358479A1 (en) * 1976-07-17 1978-02-10 Schubert & Salzer Maschinen Spinning rotor for open=end spinning machine - has strong outer support with hard wearing inner segments to form spinning surface
FR2381842A1 (en) * 1977-02-25 1978-09-22 Platt Saco Lowell Ltd PERFECTED ROTOR FOR FREE FIBER SPINNING MACHINE

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3431944A1 (en) * 1983-09-09 1985-03-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho, Kariya, Aichi Rotor for an open-end spinning machine
US6195976B1 (en) 1999-03-09 2001-03-06 W. Schlafhorst Ag & Co. Spinning rotor for open-end spinning machines
USRE40759E1 (en) 1999-03-09 2009-06-23 Oerlikon Textile Gmbh & Co. Kg Spinning rotor for open-end spinning machines
KR20030072092A (en) * 2002-03-05 2003-09-13 장동우 Rotor for spinning frame and manufacturing method thereof

Also Published As

Publication number Publication date
EP0009497A1 (en) 1980-04-16
FI64955B (en) 1983-10-31
NL7901186A (en) 1979-08-28
AU4452179A (en) 1979-08-30
BE874424A (en) 1979-08-23
IL56641A (en) 1982-03-31
ATA105479A (en) 1983-01-15
AR220742A1 (en) 1980-11-28
IT1111526B (en) 1986-01-13
FI790617A (en) 1979-08-25
DE2936565A1 (en) 1980-11-27
JPS55500140A (en) 1980-03-13
GB2036098A (en) 1980-06-25
AU529171B2 (en) 1983-05-26
FI64955C (en) 1984-02-10
CS220323B2 (en) 1983-03-25
IT7920339A0 (en) 1979-02-19
BR7906846A (en) 1980-02-26
ZA79747B (en) 1980-05-28
IN151789B (en) 1983-07-30
PT69263A (en) 1979-03-01
CA1106246A (en) 1981-08-04
AT372119B (en) 1983-09-12

Similar Documents

Publication Publication Date Title
US4167846A (en) Steel rotor with hardened fibre collecting groove and method of manufacture thereof
US4193253A (en) Spinning pot
US4044427A (en) Comber roll
US4698958A (en) Ring for spinning and twisting machines
WO1979000659A1 (en) Spinning rotor made from steel for open end spinning machines
US7188463B2 (en) Opening device for spinning machines
US6339883B1 (en) Method of making a roll for paper-making machine
US4195470A (en) False twisting apparatus
JP2002510755A (en) Rings for ring spinning and ring twisting machines
CN108884602A (en) It is coated with wire loop or spinning ring, the method for coating wire loop or spinning ring and the system using the wire loop or spinning ring for being coated with metal sulfide of metal sulfide
US2987871A (en) Spinning ring and method of making same
EP0593084B1 (en) Cylinders made of high speed rollers for raising machines, and process for making such rollers
EP0804642B1 (en) Card-clothing wire
US5313773A (en) Coatings for spinning applications and rings and travelers coated therewith
EP0502856A1 (en) Improved roller
US4216644A (en) Open end spinning rotor
CN101358391A (en) Spinning device of a textile machine
CN217535013U (en) High-abrasion-resistance steel wire passing wheel
CN118202099A (en) Spinning or twisting ring and ring-bead system
CN109177366A (en) A kind of anti-corrosion of metal roller and its manufacturing method
US5842337A (en) Rotor for open-end spinning machine
US20040182065A1 (en) Coated textile machinery parts
CS231639B1 (en) Spinning rotor of non-spindle ring spinning machine
CN101440494A (en) Method for coating opening roller ring and ring used for opening roller
Gallant et al. The characterization of surfaces of technical ceramics used in the synthetic fibres industry by microscopy

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): BR DE GB JP SU US

AL Designated countries for regional patents

Designated state(s): FR

RET De translation (de og part 6b)

Ref country code: DE

Ref document number: 2936565

Date of ref document: 19801127

Format of ref document f/p: P