US3712345A - Yarn clamping mechanism - Google Patents

Yarn clamping mechanism Download PDF

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Publication number
US3712345A
US3712345A US00143530A US3712345DA US3712345A US 3712345 A US3712345 A US 3712345A US 00143530 A US00143530 A US 00143530A US 3712345D A US3712345D A US 3712345DA US 3712345 A US3712345 A US 3712345A
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US
United States
Prior art keywords
arms
clamp
clamping mechanism
yarn
stop
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Legal status (The legal status 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 status listed.)
Expired - Lifetime
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US00143530A
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English (en)
Inventor
E Pfarrwaller
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Sulzer AG
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Sulzer AG
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Filing date
Publication date
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Publication of US3712345A publication Critical patent/US3712345A/en
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    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03J—AUXILIARY WEAVING APPARATUS; WEAVERS' TOOLS; SHUTTLES
    • D03J5/00—Shuttles
    • D03J5/06—Dummy shuttles; Gripper shuttles

Definitions

  • the clamping mechanism is provided with a stop member against which the clamp arms abut upon closing of the jaws.
  • the stop member and arms are dimensioned so that a fraction of the spring force biasing the arms closed is absorbed by the stop member.
  • the stop member can be mounted on the bearer member carrying the'clamp or on the clamp arms. Also, the stop member can be of various geometric forms.
  • This invention relates to a yarn clamping mechanism and, more particularly, to a yarn clamping mechanism for a weaving machine.
  • Yarn clamping mechanism have been known to consist of a carrier member, a yarn clamp which is fitted into the carrier member, is closable under a spring force and carries a pair of clamp jaws, and an opener for temporarily opening the clamp jaws.
  • these yarn clamp mechanism have been used in widely varying textile machines in which a yarn or filament has to be engaged and brought into a specific position during operation of the machine, or when a specific movement has to be performed with such yarn or the like.
  • clamping mechanisms of this type have been used in the weft yarn feeder of picking mechanisms of gripper shuttle weaving machines (for example, in accordance with one of the US. Pat. Nos. 2,845,095 or 2,728,359).
  • These yarn feeders have served to feed to the gripper shuttle, the weft yarn end which is required to be inserted into the shed on the next picking operation, and to transfer the yarn end to a clamping mechanism operating on a similar principle and incorporated in the gripper shuttle (for example in accordance with one of U.S. Pat. Nos. 2,660,201 and 3,472,286).
  • the yarn feeder engages the picker-side end of the weft yarn which has just been drawn from the bobbin (which remains outside the shed during the picking operation) and which has just been introduced into the shed.
  • the length of yarn already introduced between the feeder and the edge yarn clamp is then cut off from the next yarn a few millimeters ahead of the weft edge yarn clamp.
  • the new weft yarn end held by the feeder is returned by the feeder in the direction towards the bobbin as far as the place at which this weft yarn end is taken over for the next picking operation by another shuttle clamp which has been prepared in the picking mechanism.
  • a yarn tensioner ensures that the weft yarn remains tensioned during this return movement.
  • the feeder has to introduce the yarn end very accurately into the open shuttle clamp.
  • the position of the clamp jaws when the feeder clamp is closed is determined in relation to the gripper shuttle clamp by a separate stop on which one of the two clamp arms of the feeder which is under somewhat stronger spring biasing than the other is operatively supported.
  • the other weaker clamp arm does not have such a stop or the like, so that the spring tension operative thereon acts fully as a clamping force between the clamping jaws and serves to hold the yarn.
  • the construction andarrangement of the feeder clamp are thus not symmetrical with respect to the path of the yarn.
  • the direct adjustment of a yarn clamp of this kind is relatively complex.
  • the clamping force by which the clamping jaws are pressed against one another is selected according to the nature of the weft yarn to be introduced and according to the picking speed in order, first, to ensure reliable retention of the yarn in the clamp (no yarn losses or minimum yarn losses), and, second, to prevent damage to the yarn clamped between the jaws.
  • the yarn tension I brakes and yarn tensioners during and between consecutive picking operations is also adjusted to different degrees according to the yarn quality and picking speed in order to avoid unnecessary stress on the yarn and yet keep the yarn uniformly taut during all stages of the weaving operation.
  • vibration occurs at individual elements of the known yarn clamping mechanisms, more particularly the clamp arms, clamp jaws and springs, during operation and such vibration is caused partly by the rapid opening and closing of the clamps under the control of the clamp opener, and partly by the movements of the bearer member (the yarn feeder arm or shuttle member) and in some cases by other external influences operative during the picking operation (for example, the guidance of the shuttle as it passes through the shed).
  • Such vibration has an adverse effect on the operational reliability of the yarn clamp since it produces clamp jaw rebound and abrasion or at least favors the same.
  • the clamping force by which the jaws are pressed into contact is adjusted to a relatively considerable value, for example of the order of 2.2 kg and more for average yarns and picking speeds of about 15 to 20 meters per second. This is more than would be required to retain the yarn, if it were not necessary to allow for the clamp vibration.
  • the invention provides a yarn clamping mechanism which is constructed of a yarn clamp having a pair of spring-biased jaw-supporting clamp arms with at least one stop member having stop surfaces upon which the clamp arms bear with a fraction of the spring force when the clamp is closed.
  • the stop member may be made from a material which is not itself very resilient, for example wood or metal, but preferably at least partially is made from a material which is flexibly resilient with a damping action, for example rubber or plastics.
  • the spring force acting on the clamp jaws can be appreciably reduced as compared with the known clamping mechanisms, and by as much as one third in certain cases. Since the clamp jaws rebound on one another to a lesser extent and no longer rub on one another in the closed condition, the yarn end clamped therebetween is not treated as rigorously and the life of the clamping mechanism is increased accordingly.
  • the construction of the yarn clamping mechanism according to the invention offers the possibility of achieving greater operational reliability of the weft introduction than with the known constructions
  • the clamping mechanism can be used for weaving machines having greater weaving widths and/or for higher picking speeds or accelerations than without vibration-damping stops.
  • the invention can be embodied with various known forms of construction of clamp arms, stop members and springs.
  • the stop member can be used with a yarn feeder which is constructed with rigid spring-loaded clamp arms pivotally connected to a carrier member at their ends remote from clamp jaws at the free ends.
  • This form of yarn clamp has the advantage of a relatively strong stable construction in which the jaws are guided in exact parallel relationship to one another in every position and cannot twist relatively to one another, even if the yarn does not lie exactly in the axis of symmetry of the clamp jaws.
  • the stop member can be used in a gripper shuttle clamp wherein a pair of clamp arms are constructed as prestressed spring arms and are rigidly connected to a carrier member at their ends remote from the clamp jaws at the free ends.
  • the two clamp arms may then be made in one piece, i.e., the arms can be interconnected by a yoke in the form of a U at their ends remote from the clamp jaws, the yoke being secured, for example as by riveting, to the carrier member.
  • This type of clamp is very simple and light, and insensitive to impacts and vibrations due to external influences.
  • the stop member is secured to the carrier member of the yarn clamping mechanism.
  • the stop member is then able to provide a certain guidance and centering for the yarn clamp so that the spatial position of the clamp jaws in their closed condition is clearly defined in relation to the carrier member.
  • the clamp can be completely symmetrical thus greatly simplifying stock-keeping of component parts and allowing the finished clamp to be adjusted.
  • centering of the closed clamp ensures a perfect transfer of the yarn, for example from the feeder to the shuttle clamp.
  • the clamp simply requires securement by a single rivet instead of two rivets as previously required in the to the carrier member for structural reasons, the stop member can be secured to a clamp arm.
  • two stop members may be provided outside a pair of actuating levers for the clamp arms with the levers bearing against the stop members when the clamp is closed.
  • the resilience of the stop surfaces against which the clamp arms bear on the stop member when the clamp is closed is advantageously dimensioned according to the yarn quality to be picked and the proposed picking speed (or yarn acceleration). For example, on a changeover of a weaving machine to different operating conditions or to a different yarn quality, both the yarn feeder and the shuttles can be interchanged for those in which the yarn clamps and stop members are found to be particularly suitable for the conditions applying to the next weaving operation.
  • the distance between the stop surfaces on the stop member associated with, i.e., simultaneously operative on, the two clamp arms is adjustable.
  • the clamping mechanism may also be adapted to receive stop members which have different distances between the stop surfaces associated with the two clamp arms and which can be turned into different positions or be interchanged.
  • the distance between the stop member and clamp jaws as measured in the longitudinal direction of the clamp may be adjustable. It is thus possible to vary the length of the effective lever arm by which the clamp arms are pressed on to the supporting surfaces. In practice, this has the same effect as a variation in the resilience of a stop member mounted rigidly on the bearer member.
  • FIG. 1 illustrates an embodiment of a clamping mechanism according to the invention as used in a yarn feeder mechanism comprising two rigid clamp arms with the yarn clamp closed;
  • FIG. 2 illustrates a plan view of the yarn clamp according to FIG. 1 in partial section on the line II-II in FIG. 1;
  • FIG.v 3 illustrates an elevation of the yarn clamp shown in FIG. 1 with the clamp open
  • FIG. 4 illustrates a sectional view of the yarn clamp taken on line IVIV of FIGS;
  • FIG. 5 illustrates an elevational view of a gripper shuttle with a yarn clamp mechanism according to the invention wherein the clamp arms are constructed as spring arms;
  • FIG. 6 illustrates a plan view taken on line VI -VI of FIG. 5 of the shuttle
  • FIG. 7 illustrates an elevational view of the cylindrical stop member provided with damping stops as shown in FIG. 5;
  • FIG. 8 illustrates a partial sectional view through a gripper shuttle similar to FIG. 5 but with a different embodiment of the stop member secured to a clamp arm;
  • FIG. 9 illustrates a view taken along line IX-IX of FIG. 10 of a gripper shuttle similar to FIG. 6 but with a stop member having adjustable resilience;
  • FIG. illustrates a view taken on line X-X of FIG.
  • FIGS. 11 and 12 are'two similar views of FIGS. 3 and 4 but with an axially adjustable stop member, those parts which are the same as FIGS. 3 and 4 having been omitted;
  • FIGS. 13 and 14 are a section and elevation similar to FIGS. 9 and 10 but with a stop member of hexagonal cross-section;
  • FIG. illustrates a diagrammatic view of a stop member of oval cross-section.
  • the carrier member 1 for a weft yarn feeder is in the form of a profiled rail which is displaceable forward and back as a unit in the direction of the arrow 3 in manner known per se to engage and guide a weft yarn 2 or a weft yarn end.
  • the carrier member 1 mounts a clamp therein which is constituted by a pair of clamp jaws 4 situated at the free ends of a respective pair of rigid clamp arms 5 which, at their ends remote from the clamp jaws 4, are pivotally connected to the carrier member 1 by pivots 6.
  • the clamp arms 5 are extended, beyond the bores surrounding the pivots 6, in the form of actuating levers 7 into which a hard metal plate 8 is recessed at the place at which a fork-shaped opener 9 meets the actuating levers 7 to open the clamp when the opener 9 moves transversely of the plane of the carrier member 1 in the direction of the arrow 10.
  • Two spring arms 11, which at one end are rigidly secured to the carrier member 1 by rivets l2, exert an outwardly directed spring force on the actuating levers 7 at their free ends so that the levers 7 are formed apart and the jaws 4 are pressed towards one another as long as the opener 9 is in a rearward inoperative position out of engagement with the actuating levers 7.
  • a stop member 15 is secured, for example by a rivet, in the carrier member 1 between the clamp arms 5 and consists of a material which is itself solid, for example wood or metal, or preferably at least partly of a material which is resiliently flexible with a damping action, for example, rubber or a plastic such as Nylon, Teflon, or
  • the stop member 15 also has damping stop surfaces 16 on which the spring-biased clamp arms 5 bear by a fraction of the spring force operative thereon, when the clamp is closed, the remaining spring force serving to press the jaws 4 together, (i.e., to engage the yarn 2.
  • the contact pressure by which the jaws 4 are pressed against one another is freely selectable or adjustable within wide limits on the basis of empirical values and depends on the properties of the yarn 2 used, such as, the yarn diameter, weight, strength, elasticity, etc. In this embodiment, the contact pressure is determined by the shape and the adjustment (for example, by subsequent cold deformation) of the spring arms 11, and by the position, shape and resilience of the stop member 15.
  • the stop member 15 is compressed by an amount x at the stop surfaces 16 by the clamp arms 5 as a result of the inherent resilience thereof when the clamp is closed.
  • the stop member 15 resumes its original shape, for example, a cylindrical shape, owing to the elasticity thereof.
  • the clamp is open, there is no longer any contact between the arms 5 and the damping surface 16.
  • the shape and dimensions of the clamp arms 5, the actuating levers 7, 8 and the spring arms 11, and the biasing of the spring arms 11 influence the type of oscillations or vibrations which experience has shown would occur in operation without the stop member 15 at the individual elements when the clamp is actuated by the opener 9 or as a result of other external effects.
  • the dimensions, the shape and the mechanical properties of the stop member 15 and of the clamp arms 5 determine the efficiency, more particularly the damping properties, ofthe clamping mechanism according to the invention.
  • the stop member 15 can alternatively be replaced by a pair of stop members 15a each of which is provided on each of two cross-members 1a, 1b of the carrier member 1 with the respective one of the actuating levers 7 bearing there against when the clamp is closed.
  • These stop members 15a are also of a material and a construction to be resiliently flexible with a damping action.
  • the yarn feeder or the yarn clamping mechanism shown in FIGS. 1 to 4 is of completely symmetrical construction with respect to the yarn path.
  • the jaws 4 in the closed condition i.e., with the yarn end held therein, should be in an accurately determined position immediately adjacent the open shuttle clamp at the moment of transfer. This is achieved with a substantially play-free accurate guidance of the carrier member 1 in the weaving machine picking mechanism (not shown), by the fact that the spring-biased clamp arms 5 pivot freely about their pivots 6 close around the stop member 15 and bear against the stop surfaces 16 on both sides.
  • the stop member 15 thus centers the closed clamp and holds the clamp, together with the yarn end held thereby, exactly in the required position with respect to the carrier member 1 and hence to the gripper shuttle clamp.
  • the yarn clamping is incorporated into a weaving machine gripper shuttle which cooperates with a weft yarn supply bobbin remaining outside the shed during picking.
  • the carrier member is in the form of a sleeve 21 of a one-piece or multi-part shuttle member of conventional construction.
  • the shuttle member sleeve 21 comprises a solid head 22 and, at the rear, an opening 23 through which the yarn clamp 24, 25, 31 is introduced and installed in the shuttle.
  • a slot-shaped opening 27 is also formed in the rear end of the sleeve 21 with the jaws 24 disposed in the region of the opening so that the jaws 24 are accessible but are protected from external influences.
  • the clamp arms 25 are in the form of prestressed spring arms and are reinforced by thickened portions or hard metal plates 28 which are aligned with bores 26 in the side walls of the sleeve 21.
  • the bores 26 permit passage of a clamp opener 29 which presses against the thickened portions 28 via a wedge-shaped edge 33 during movement forward and back in the direction of the arrow 30, to open the arms 25 and hence the jaws 24, i.e., the clamp.
  • the two spring arms 25 are interconnected by a yoke 31 and is made in one piece.
  • the yoke 31, in turn, is secured to the carrier member (sleeve 21) for example, by means of a rivet 32.
  • a substantially cylindrical stop member 35 (FIG.
  • the stop member is secured to the carrier member in any desired manner, for example riveted, screwed, pressed in or glued. If a seperable connection is required, the damping properties can be adjustable to a certain degree to adaptto the requirements of different types of filaments or yarns, for example, by providing in terchangeable stop members 15, 35 which has different distances widths over flats between their opposite stop surfaces 16.
  • the stop member may also be cube shaped 37 and may be secured to one of the clamp arms 25 so as to have one stop surface 38 (FIG. 8).
  • the stop member can be in the form of a hexagon 35b (FIGS. 13 and 14), octagon, etc. and can be provided with a spacer bush 41b so as to be non-compressi ble in the longitudinal direction.
  • These members as shown, can be secured to the sleeve 21 by a counter sunk screw 42b.
  • members are then used which have widths over flats?
  • a resilient stop member 35a is of cylindrical construction in comparison with 35b in FIG. 13 and can be compressed in its longitudinal direction transversely of the sleeve 21 by a pressure plate 41 and a countersunk screw 42 so that the diameter 39 and resilience thereof are adjustable with respect to the clamp arms 25 within certain limits according to the required purpose.
  • the stop member consists of a rigid metal block 43 and, if required, is provided with stop buffers 44 which are flexibly resilient with a damping action. These buffers 44 have flat stop surfaces which are spaced apart by a distance 39 as above described.
  • the block 43 is guided in a longitudinal slot 45 of the carrier member 1 by appropriately constructed guide edges and is clamped adjustably in the longitudinal direction by means of a screw 42a with a washer. In this way, the distance 40 between the jaws 4 and the stop member 43, 44, i.e., the length of the clamp arm lever operative for the stop, can be adjusted as required.
  • a yarn clamping mechanism comprising a carrier member
  • a yarn clamp mounted in said carrier member and having a pair of spring biased arms therein and a jaw on each said arm;
  • At least one resilient and damping stop member having stop surfaces thereon for temporarily engaging each of said arms with a fraction of the spring force with said jaws closed on each other and being spaced from said arms with said jaws opened with respect to each other;
  • an opener for temporarily opening said jaws.
  • each said arm is rigidly constructed and pivotally connected to saidcarrier member at an end remote from said jaws thereon.
  • each said arm is a prestressed spring arm rigidly connected to said carrier member at an end remote from said jaw thereon.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
  • Spinning Or Twisting Of Yarns (AREA)
US00143530A 1970-05-29 1971-05-14 Yarn clamping mechanism Expired - Lifetime US3712345A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH805570A CH502462A (de) 1970-05-29 1970-05-29 Fadenklemmvorrichtung

Publications (1)

Publication Number Publication Date
US3712345A true US3712345A (en) 1973-01-23

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Application Number Title Priority Date Filing Date
US00143530A Expired - Lifetime US3712345A (en) 1970-05-29 1971-05-14 Yarn clamping mechanism

Country Status (9)

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US (1) US3712345A (ro)
AT (1) AT304394B (ro)
CH (1) CH502462A (ro)
CS (1) CS159278B2 (ro)
FR (1) FR2093860A5 (ro)
GB (1) GB1354023A (ro)
HU (1) HU169132B (ro)
PL (1) PL70915B1 (ro)
RO (1) RO67834B (ro)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3854506A (en) * 1972-05-26 1974-12-17 Sulzer Ag Gripper shuttle
JPS51100783A (en) * 1975-02-28 1976-09-06 Yamada Yuki Seizo Co Ltd Hoirubaransani okeru enzankairono kiseihoho
US5441086A (en) * 1993-02-18 1995-08-15 Sulzer Ruti Ag Gripper shuttle for a loom
US10709317B2 (en) * 2018-10-04 2020-07-14 PraesidioDyne, LLC Clamp assembly for disposable endoscopic sheaths

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE68906663T2 (de) * 1988-12-16 1993-08-26 Werner Sollberger Greiferprojektil fuer webmaschinen.
DE102015119971A1 (de) * 2015-11-18 2017-05-18 Gianfranco Di Natale Webmaschinenprojektil und Verfahren zur Herstellung eines Webmaschinenprojektils

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2660201A (en) * 1951-01-08 1953-11-24 Warner Swasey Co Jaw holder for gripper shuttle looms
US2728359A (en) * 1954-07-19 1955-12-27 Sulzer Ag Thread clamp for looms for weaving
FR1216556A (fr) * 1958-12-01 1960-04-26 Dispositif pour l'insertion du fil de trame dans les métiers à tisser à navette, et métier muni de ce dispositif
US3472286A (en) * 1967-03-08 1969-10-14 Sulzer Ag Gripper shuttle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2660201A (en) * 1951-01-08 1953-11-24 Warner Swasey Co Jaw holder for gripper shuttle looms
US2728359A (en) * 1954-07-19 1955-12-27 Sulzer Ag Thread clamp for looms for weaving
FR1216556A (fr) * 1958-12-01 1960-04-26 Dispositif pour l'insertion du fil de trame dans les métiers à tisser à navette, et métier muni de ce dispositif
US3472286A (en) * 1967-03-08 1969-10-14 Sulzer Ag Gripper shuttle

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3854506A (en) * 1972-05-26 1974-12-17 Sulzer Ag Gripper shuttle
JPS51100783A (en) * 1975-02-28 1976-09-06 Yamada Yuki Seizo Co Ltd Hoirubaransani okeru enzankairono kiseihoho
US5441086A (en) * 1993-02-18 1995-08-15 Sulzer Ruti Ag Gripper shuttle for a loom
US10709317B2 (en) * 2018-10-04 2020-07-14 PraesidioDyne, LLC Clamp assembly for disposable endoscopic sheaths

Also Published As

Publication number Publication date
PL70915B1 (ro) 1974-04-30
GB1354023A (en) 1974-06-05
RO67834B (ro) 1983-04-30
CS159278B2 (ro) 1974-12-27
RO67834A (ro) 1983-04-29
CH502462A (de) 1971-01-31
AT304394B (de) 1973-01-10
DE2057383A1 (de) 1972-01-27
HU169132B (ro) 1976-09-28
FR2093860A5 (ro) 1972-01-28

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