WO2005100221A1

WO2005100221A1 - Yarn feeder

Info

Publication number: WO2005100221A1
Application number: PCT/EP2005/003955
Authority: WO
Inventors: Gerardo Salton
Original assignee: Iro Ab
Priority date: 2004-04-15
Filing date: 2005-04-14
Publication date: 2005-10-27
Also published as: EP1735227A1; EP1735227B1; CN1950282A; CN100567116C; SE0400993D0

Abstract

A yarn feeder (W) comprising a variable diameter stationary storage body (13) consisting of separated segments (S, SA) received in radial guidances (7) of a support structure (B), each segment comprising at least one finger (F) and a rod (R) unitarily formed with the finger (F), the rod (R) being connected to the lower side of the finger in a junction region, the rod carrying engagement elements (3) at a front side (8) and defining longitudinal guiding surfaces (G) at other sides of the rod, the junction region (1) having at least a gusset (5a) at the transition between the front side (8) and the lower side of the finger, the junction region (1), furthermore, comprising an additional gusset (5b) at a transition from the rear side of the rod into the lower side of the finger. The guiding surfaces (G)- in a crosssection of the rod (R)- being arranged pairwise and with a V-shape.

Description

YARN FEEDER

The invention relates to a yarn feeder according to the preamble part of claim 1.

Among yarn feeders used at weaving machines so-called measuring yarn feeders particularly designed for use at jet weaving machines like air jet weaving machines and water jet weaving machines exist. The insertion device of a jet weaving machine is unable to measure the correct yarn length for a pick. For that reason the measuring yarn feeder is equipped with a stopping device for releasing a certain full number of yarn windings only during each pick. The weaving width of an air jet machine can vary. The diameter of the storage body is variable in order to match the length of the yarn released by the stopping device during each pick with the weaving width (variable diameter storage body ). The storage body of measuring yarn feeders conventionally comprises several separate segments which are held by rods in radial guidances of a support body of the yarn feeder. Each segment may comprise several essentially axially extending, circumferentially separated fingers and a common rod. In case that the yarn feeding is operating with yarn separation (the yarn windings on the fingers, constituting yarn storage surfaces, are separated from each other) a separating segment is loosely integrated into each stationary segment of the storage body. The separating segment is held by a rod in a separating support body of the yarn feeder. The separating support body wobbles during operation of the yarn feeder such that the fingers of the separating segments convey the yarn windings on the stationary segments in withdrawal direction and separate the windings from each other. Each segment is locked in an adjusted position by an integrated clamping device of the yarn feeder pressing the rod of the segment into the guidance of the support body. For changing the adjustment position the clamping device is temporarily untightened such that the rods can be radially displaced by an adjustment drive engaging at the engagement elements provided at the front side of the rod. Due to unavoidable vibrations during the operation of the yarn feeder the junction region in each segment is prone to damage and the free end portion of the segment tends to vibrate considerably when a diameter of the storage body is adjusted which is bigger than the minimum diameter, because then a significant part of the length of the rod is no longer supported by the guidance in the support body. Those drawbacks result from the design of conventional segments, particularly in the junction region and of the guiding surfaces of the rod and in the guidance. Figs 6-9 illustrate a conventional segment design. The segment consists of several fingers F' each defining a yarn storage surface 2'. A rod R' of essentially rectangular cross-section is unitarily connected to the finger F' in a junction region 1 '. The junction region 1 ' is stiffened by a gusset 5' at the junction between a front side 8' of the rod R' and the lower side of the finger F'. The front side 8' carries engagement elements 3', while the rear side of the rod R has longitudinally extending grooves 6'. Side surfaces 14' and the surfaces in the grooves 6' constitute longitudinal guiding surfaces G' of the rod R' which guiding surfaces G' co-act with longitudinal guiding surfaces 7' of a support body B' of the yarn feeder. As soon as the segment S' is locked in a selected adjustment position, a symbolically shown clamping device K generates a clamping force which is oriented essentially perpendicular to the front side 8' of the rod R'.

It is an object of the invention to provide a yarn feeder as mentioned above in which the segments of the storage body are not prone to failures and do not vibrate significantly even in adjustment positions for a larger storage body diameter than the minimum diameter.

Said object can be achieved by the features of claim 1.

Since the junction region not only is stiffened towards the front end portion of the segment but also towards the rear end portion of the segment, the junction region is very rigid. Vibrations occurring during operation of the yarn feeder as well as the forces of the yarn windings carried by the segments hardly can cause oscillating motions of the fingers even when a bigger diameter is adjusted than the minimum diameter of the storage body, and provided that the rod is well guided and supported in the guidance of the support body. The guiding quality of the rod in the guidance of the support body is enhanced by the V- arrangement of the guiding surfaces and the co-action of the guiding surfaces with mating guiding surfaces in the guidance. The V-arrangement results in an intensified securement of the rod by the clamping force of the clamping device, because oblique surfaces are firmly pressed against each other, and because the V-arrangement of the guiding surfaces leads to larger contact areas. Moreover, the guiding surfaces in the V-arrangement, seen in a cross-section of the rod, may be designed relatively long resulting in a material concentration at the rear side of the rod which increases the moment of inertia and the bending stiffness of the rod such that the not supported longitudinal section of the rod (in the case of a large diameter adjustment) is unable to flex. Both measures in combination improve the resistance of the segment against breakages in the junction region and suppress any tendency of the fingers to vibrate, practically in all directions in relation to the stationary part of the yarn feeder. The operation performance of the yarn feeder is improved significantly. The modifications needed at the segment and for the guidances are simple. A large adjustment range can be achieved despite the increased stiffness in the junction region.

Large contact areas for guiding and clamping the rod can be achieved by guiding surfaces defined by the side surfaces of the rod, which guiding surfaces converge in a direction from the front side towards the rear side of the rod. The tapering cross-section improves the guiding performance and results in a safe locking function. Moreover, by the tapering cross-section a mass concentration in the rear side of the rods easily can be achieved resulting in an increased bending stiffness of the rod.

in a preferred embodiment at least one pair of guiding surfaces is provided in the rear side of the rod which guiding surfaces converge in a direction from the rear side towards the front side. By the additional guiding surfaces the total contact area for guiding and locking purposes is increased already by the cross-section design of the rod.

In another preferred embodiment even two pairs of V-shaped guiding surfaces are defined in the rear side of the rod with a longitudinal rib in-between. The structure multiplies the guiding surfaces such that a large contact area is achieved. The longitudinal rib improves the bending stiffness of the rod and may even be continued into the additional gusset at the rear side. Preferably, the longitudinal central rib even is higher for stiffness purposes than the ribs created at both sides of the rod.

Expediently, the strengthened segment is a segment of the stationary storage body and is clamped by the clamping device in the guidance of the stationary support body. The clamping force is acting essentially perpendicular to the front side of the rod such that the converging guiding surfaces are brought into firm contact with the guidance.

In the case of a yarn feeder operating with yarn separation, alternatively or additively, respectively, the segment may be a separating segment which can be driven for a wobbling motion in relation to the stationary storage body segments. Embodiments of the invention as well as a prior art design are shown in the drawings. In the drawings is:

Fig.1 a side view of a front part of a yam feeder,

Fig.2 a perspective view of a segment of the storage body of the yarn feeder of Fig. 1,

Fig.3 a sectional side view in the section plane Ill-Ill in Fig. 2,

Fig. 4 a sectional view in the direction of an arrow IV in Fig. 3,

Fig. 5 a section in the section plane V-V in Fig. 4,

Fig. 5a a sectional view similar to Fig. 5 of another embodiment,

Fig. 6 a perspective view of a segment of a storage drum according to prior art,

Fig. 7 a sectional view of the conventional segment of Fig. 6,

Fig. 8 a rear view of the conventional segment in the direction of an arrow VIII in Fig. 7, and

Fig. 9 a sectional view in the section plane IX-IX in Fig. 8.

The conventional segment S' shown in Figs 6-9 has been designated reference numbers with primes. The same reference numbers appear in Figs 1-5a of embodiments of the invention without the notation prime.

The yarn feeder W, as partly shown in Fig. 1 , is a so-called measuring yarn feeder as conventionally applied at jet weaving machines. The yam feeder W has a housing 10 stationarily supporting a storage body 13. A stopper housing 11 , fixed to the housing 10, is structurally associated to the outer circumference of the storage body 13 at a circumferential location of one segment S of totally e.g. four at least substantially identical segments S regularly distributed in circumferential direction of the storage body 13. Each segment S consists of several essentially parallel fingers F, each of which is constituting a yarn storage surface 2, and of a rod R extending essentially perpendicular to the lower side of the central finger F. Each rod R serves for the fixation and radial adjustment of one segment S in relation to a support body B which is stationarily supported in relation to the housing 10. A winding element 12 is provided between the storage body 13 and the housing 10 and can be driven in order lay down yarn windings on the storage body 13.

In a not shown alternative the yarn feeder W could be equipped with a storage body 13 only consisting of the stationary segments S. In the shown embodiment, however, the yarn feeder operates with yarn separation. For this purpose additional segments SA are provided which are positioned with axial fingers FA in the interspaces between the fingers F of the stationary segments S. The segments SA are so-called separating segments and can be driven for a wobbling motion in relation to the stationary segments S. Each segment SA is fixed by a rod RA which is unitarily connected to one of the fingers FA at the lower side and extends into a support body BA which wobbles when the yarn feeder is operating (conventional technique).

The storage body 13 contains an adjusting device (not shown) and a clamping device (not shown), both for either adjusting the radial position of each rod R, RA in relation to the axis of the storage body 13 or to lock the respective rods R, RA as soon as a selected radial adjustment position has been set. The stopper housing 11 as well may be adjustable in radial direction.

Figs 2-5a illustrate embodiments of a segment S for the yarn feeder W of Fig. 1. The segment S has design features according to the invention. Figs 2-5a represent one of the stationary segments S of Fig. 1 , e.g. the lowermost segment in Fig. 1. The design features according to the invention, however, could also be implemented into the segments SA, which by their wobbling motion co-act with the stationary segments S in order to convey the yarn windings in Fig. 1 from the right side in axial direction to the left and in order to, furthermore, produce a yarn separation of a selectable extent between the yarn windings. The segment S in Fig. 2 consists of five essentially parallel fingers F with axial interspaces between adjacent fingers F. The fingers F are interconnected at their front and rear end portions. The central finger F is somewhat broader than the other fingers F. Each finger F constitutes a yarn storage surface 2 by its upper periphery.

The rod R of the segment S is unitarily connected to the central finger F in a junction region 1. The rod R is essentially as broad as the finger F. In the junction region 1 gussets 5a and 5b are provided at the transition between the front surface 8 of the rod R and the lower side of the central finger F and at the transition between the rear side (not visible in Fig. 2) of the rod R and the lower side of the central finger F in order to increase the bending stiffness and the torsional stiffness in the junction region 1. The front surface 8 carries engagement elements 3 which co-act in the yarn feeder with the not shown adjustment drive for longitudinally, i.e. radially, moving the rods R in relation e.g. to the axis of the storage body 13.

As indicated in Figs 3 and 4, the rear side may be flat, or at least one longitudinal groove 6 may be formed in the rear side of the rod R. In Fig. 5 a single longitudinal groove 6 is formed in the rear side. The groove 6 has side flanks constituting longitudinal guiding surfaces G which converge in a direction from the rear side to the front side 8. The side surfaces 14 of the rod R (in a cross-section as in Fig. 5) are planar and converge in a direction from the front side 8 towards the rear side. A guidance 7 of trapezoidal cross- section in the support body B, even may have, in case that the groove 6 is provided, a rib co-acting with the guiding surfaces G in the groove 6.

The clamping device K is indicated by an arrow illustrating the direction of the clamping force generated for locking the rod R in a selected adjustment position. The force is essentially perpendicular to the front surface 8 of the rod R and presses the guide surfaces G into firm contact with the guide surfaces of the guidance 7. When the clamping device K is untightened the rod R can be displaced perpendicular to the drawing plane in Fig. 5 by co-action between the not shown adjustment drive and the engagement elements 3.

As shown in Figs 3 and 4, the junction region 1 is characterised by a massive material concentration in the front and rear gussets 5a, 5b and the relatively thick rod R (measured in the drawing plane in Fig. 3). Moreover, as indicated in dotted lines in Fig. 4, even reinforcing rib sections 16 might be provided which form the side surfaces 17 of the finger F, and additionally stiffen the junction region 1. The groove 6 in the rear side of the rod R is starting with a distance from the junction region 1 such that the full cross-section of rod R will be provided in the junction region 1.

Fig. 5a illustrates another embodiment of the cross-sectional design of the rod R according to the invention. Both side surfaces 14 of the rod R define longitudinal and relatively broad guiding surfaces G. The guiding surfaces G, which are provided pairwise and symmetrically with respect to the central axis of the rod R, converge in a direction from the front surface 8 towards the rear surface of the rod R. In the rear surface two pairs of longitudinally extending guiding surfaces G are formed by grooves such that in each pair the two guiding surfaces G converge in a direction from the rear side towards the front side 8. In-between both grooves 6 a central longitudinal rib 18 is provided which e.g. is higher than the ribs forming the side surfaces 14. Of course, the guidance (not shown in Fig. 5a) has mating guiding surfaces for the co-action with the guiding surfaces G of the rod R. The guidance and the locking function, both mainly occur between the oblique guiding surfaces of the rod R and mating guiding surfaces of the guidance.

The segments S preferably are metallic die cast parts with a special wear resistant coating at least on the yarn storage surfaces 2 of the fingers F.

Claims

1. Yam feeder (W), comprising a variable diameter stationary storage body (13) consisting of separated segments (S, SA) which are adjustably received in radial guidances (7) of a support structure (B), each segment comprising at least one finger (F, FA) and a rod (R) unitarily formed with the finger (F) which rod is connected with the lower side of the finger in a junction region and extends essentially perpendicular to the lower side of the finger, carries engagement elements (3) at a front side (8) and has longitudinally extending guiding surfaces (G) at other rod sides, the junction region (1) comprising at least at a transition portion between the front side (8) and the lower side of the finger an integrated gusset (5a), characterised in that the junction region (1) is provided in a transition from the rear side of the rod (R) into the lower side of the finger (F, FA) with an additional gusset (5b), and that the guiding surfaces (G) - in a cross-section of the rod (R) - are provided in a pairwise V- arrangement.

2. Yarn feeder as in claim 1 , characterised in that the side surfaces (14) of the rod (R) define a pair of guiding surfaces (G) converging in a direction from the front side (8) towards the rear side.

3. Yam feeder as in claim 1 , characterised in that at least one pair of guiding surfaces (G) converging in a direction from the rear side of the rod towards the front side (8), are provided in the rear side of the rod.

4. Yarn feeder as in claim 1 , characterised in that the additional gusset (5b) comprises rib portions (16) forming side walls (17) of the finger (F), the height of the rib section (16) increasing in a direction towards the rod.

5. Yarn feeder as in claim 3, characterised in that a longitudinal rib (18) is provided in the rear side of the rod (R) between two pairs of V-shaped guiding surfaces (G).

6. Yarn feeder as in claim 1 , characterised in that the segment (S) is fixed in each of different adjustment positions in stationary guidances (7) of the yarn feeder (W) by means of a clamping device (K) generating a clamping force which is oriented substantially perpendicular to the front side (8).

7. Yarn feeder as in claim 1 , characterised in that the segment (SA) is fixed in each of different adjustment positions in guidances of a wobbling support body (BA) by a clamping device generating a clamping force which is essentially perpendicular to the front side of the rod (RA).