CA1065137A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Methods and apparatus for coating filaments
Assignee: Post Office
•
Filing: 1975-06-27
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Granted: 1979-10-30
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Expires: 1995-06-27
Abstract
Abstract ABSTRACT This invention relates to a method which facilitates the production of covered filament in that it enables a cover-ing to be applied to a filament at a speed compatible with the speed of filament production, and which permits substantial increases in the rate of production of covered filament. The method comprises the steps of pulling the filament from a melt of filament material, applying longitudinally at least one protective tape covering to the filament to envelope the latter, applying heat to the tape(s), and closing the envelope longitudinally. The, or each, tape has a backing strip of a high melting point plastics material and, on the side adjacent the filament, a coating of a low melting point plastics material. The backing strip provides the mechanical strength of the tape and the coating provides a bonding material for effecting closure of the said envelope around the filament, and the method is carried out in such a manner that, in the covered filament, the or each tape is bonded not more than partially to the filament. The invention also provides apparatus for carrying out such a method.
Inventors
- 👤 Clifford D. Smith
- 👤 John E. Midwinter
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-30 17:11
CPC Classifications
C; C03; C03C; C03C25/00; C03C25/10; C03C25/12; G; G02; G02B; G02B6/00; G02B6/44; G02B6/4479; G02B6/4486
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
165 words
A method of producing a covered filament, comprising the steps of supplying the filament from a melt of filament material, applying at least one tape to the filament to envelop the filament, the or each tape extending in the longitudinal direction of the filament, applying heat to the, or at least one of the, tapes, and closing the envelope in the said longitudinal direction, in which the or each tape comprises a backing strip of a plastics material with a high melting point which provides the mechanical stre-ngth of the tape and, on one side only of the strip, a coating of a plastics material with a low melting point, which provides a bonding material for effecting the said closure of the envelope, and in which the or each tape is applied to the filament with the coating in contact with the filament, the method being such that, in the covered fila-ment the or each tape is bonded not more than partially to the filament.
Claim 2
Independent Claim
165 words
A method of producing a covered filament, comprising the steps of supplying the filament from a melt of filament material, applying at least one tape to the filament to envelop the filament, the or each tape extending in the longitudinal direction of the filament, applying heat to the, or at least one of the, tapes, and closing the envelope in the said longitudinal direction, in which the or each tape comprises a backing strip of a plastics material with a high melting point which provides the mechanical stre-ngth of the tape and, on one side only of the strip, a coating of a plastics material with a low melting point, which provides a bonding material for effecting the said closure of the envelope, and in which the or each tape is applied to the filament with the coating in contact with the filament, the method being such that, in the covered fila-ment the or each tape is bonded not more than partially to the filament.
Claim 3
Dependent Claim
41 words
A method as claimed in claim 1, in which the filament is pulled from the melt and in which a part at least of the force required to effect the pulling is applied to the filament via the or each tape.
Claim 4
Dependent Claim
46 words
A method as claimed in claim 1, in which a single tape is employed and in which the single tape is formed into an open, longitudinal, trough-shaped configura-tion, the filament being then led into the trough after which the trough is closed to envelop the filament.
Claim 5
Dependent Claim
62 words
A method as claimed in claim 1, in which two tapes are used to envelop the filament, and in which the method comprises the steps of feeding the filament and the face of one of the tapes into contact with each other and then applying the second tape to that face of the one tape with which the filament is in contact.
Claim 6
Dependent Claim
59 words
A method as claimed in claim 4, in which the one tape is first formed into an open, longitudinal trough-shaped configuration prior to being fed into contact with the filament, the filament then being fed into the trough after which the one tape is caused to resume a transversely flat configuration prior to the application of the second tape.
Claim 7
Dependent Claim
62 words
A method as claimed in claim 1, in which two tapes are used to envelop the filament, and in which the method comprises the steps of engaging the filament between the surfaces of the two tapes and placing the surfaces together, to envelope the filament, and rotating the enveloped filament through 90° about its longitudinal axis after which the envelope is closed.
Claim 8
Dependent Claim
30 words
A method as claimed in claim 1, in which the tape coating is of a thermo-plastics material and in which the closing of the envelope is effected by heat sealing.
Claim 9
Dependent Claim
189 words
Apparatus for carrying out a method as claimed in claim 1, comprising means for producing a melt of filament material and means for supplying a filament from the melt; supplies of first and second tapes, each of the tapes comprising a backing strip of a plastics material with a high melting point, which provides the mecanical strength of the tape and which has, on one side only, a coating of a plastics material with a low melting point; means for applying heat to at least one of the tapes; a first mechanism for applying the first tape to the filament so that the first tape extends in the longitudinal direction of the filament with the coating in contact with the filament, and a second mechanism for feeding the second tape into face contact with the coating on the first tape so that the second tape also extends in the said longitudinal direction with the coating on the second tape contacting the coating on the first tape to envelop the filament, and means for bonding the tapes to one another and, but not more than partially, to said enveloped filament.
Claim 10
Dependent Claim
33 words
Apparatus as claimed in claim 8, in which the first mechanism includes means for forming the first tape into an open, longitudinal, trough-shaped configuration, and means for feeding the filament into the trough.
Claim 11
Dependent Claim
65 words
Apparatus as claimed in claim 9, in which the means for forming the first tape into a trough-shaped configuration comprises a wheel with a peripheral groove, and in which the second mechanism includes a roller for returning the first tape to a plan transverse configuration and means for feeding the second tape to the roller into contact with the first tape to envelop the filament.
Claim 12
Dependent Claim
103 words
Apparatus as claimed in claim 8, including a first pair of co-operating rollers rotatable about parallel axes, the first and second mechanisms being operable to feed the first and second tapes to the nip of the first roller pair, a second pair of co-operating rollers rotatable about parallel axes, and means for feeding the filament to the nip of the first pair of rollers so as to be enveloped by the first and second tapes, the tapes and the filament enveloped thereby then passing between the second pair of rollers to bond the tapes to one another to effect closure of the envelope.
Claim 13
Dependent Claim
49 words
Apparatus as claimed in claim 11, in which the axes of the second pair of rollers lie in planes parallel to the planes containing the axes of the first pair of rollers, the axes of the second pair being at right angles to the axes of the first pair.
Claim 14
Dependent Claim
27 words
Apparatus as claimed in claim 11 or claim 12 and further comprising driving means for driving at least one roller of at least one pair of rollers.
Claim 15
Dependent Claim
30 words
Apparatus as claimed in claim 8, in which the means for bonding the tapes to one another comprises pressure rollers for pressing the tapes together after envelopment of the filament.
Claim 16
Dependent Claim
46 words
Apparatus as claimed in claim 11, in which one of the first pair of rollers comprises a rotatably-mounted annulus whose outer curved surface is contoured to receive one of the tapes, and in which the heat applying means comprises an induction heater for heating the annulus.
Claim 17
Dependent Claim
154 words
Apparatus for carrying out a method as claimed in claim 1, comprising a wheel having a peripheral groove; a supply of a tape comprising a backing strip of a plastics material with a high melting point, which provides the mechanical strength of the tape and which has, on one side only, a coating of a plastics material with a low melting point, means for applying heat to the tape; a mechanism for feeding the tape to the groove whereby the tape is formed into an open, longitudinal, trough-shaped configuration; means for producing a melt of filament material and means for supplying a filament from the melt into said open trough-shaped tape, means for closing the trough by bringing into contact the opposed faces of said formed tape to envelop said filament, and means for bonding the opposed faces of the tape to one another and, but not more than partially to said enveloped filament.
References Cited (Backward Citations)
No citation records indexed.
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