EP1888826B1

EP1888826B1 - Terry loom and backrest arrangement for a weaving machine

Info

Publication number: EP1888826B1
Application number: EP06754175A
Authority: EP
Inventors: Jürgen WARMER; Filip Deconinck; Veerle Vanwassenhove
Original assignee: Picanol NV
Current assignee: Picanol NV
Priority date: 2005-06-10
Filing date: 2006-06-07
Publication date: 2010-12-29
Anticipated expiration: 2026-06-07
Also published as: CN101194057B; WO2006131325A3; CN101194057A; DE102005028127A1; ATE493528T1; DE602006019237D1; EP1888826A2; WO2006131325A2

Abstract

In the case of a terry loom, provision is made for the cloth (20) to be displaceable relative to a device for beating up weft yarns through to-and-fro motion of backrest and breast beam, wherein only the backrest for the ground warp and the breast beam may be moved to and fro by means of a drive, while the backrest (16) for the pile warp (13) is held so as to be resiliently compliant substantially in the weaving direction.

Description

The invention relates to a terry loom with devices for supplying a ground warp and a pile warp, with a backrest for the ground warp and a backrest for the pile warp which backrest is held resiliently substantially in weaving direction, with a shedding device, with a device for inserting weft yarns, with a device for beating up the weft yarns and with a device for drawing off cloth, which comprises a breast beam, and a backrest arrangement
Terry looms of the above-mentioned type have long been known, for example from US 607 377 or from US 15 95 289 . Displacement of the cloth relative to the device for beating up a weft yam causes variation of the distance between the always constant beat-up line and the fell. If, after a plurality of picks and beat-ups effected at a distance from the fell, the cloth is displaced in such a way that the fell is moved closer to the reed, the previously inserted weft yarns are carried along towards the fell. In the process, they move relative to the more tightly tensioned warp yarns of the ground warp, while carrying with them the only loosely tensioned warp yarns of the pile warp. In the process, the warp yarns of the pile warp form loops. In order to displace the cloth relative to the beating-up device, the backrests for the ground warp and pile warp are moved to and fro by means of a drive means jointly with and in the same direction as the breast beam.
Terry looms having a backrest arrangement with a backrest which is resiliently held in weaving direction are known by US-A-3 910 317 , US-A-4 403 630 , DE-A 196 26 417 . The backrest, which is also called tensioning beam, is a roller which is rotatably held at both ends by means of pivotable arms. The pivotable arms are loaded by springs. Backrest arrangement including leaf springs are known from EP 0487126A and EP 0409811A .
The object of the invention is to simplify a loom of the above-mentioned type by an improved backrest and to provide an improved backrest arrangement.
This object is achieved for a terry loom by the features of claim 1 and for a backrest arrangement the features of claim 10.
The resilient mounting of the pile warp backrest insures that, on movement of the warp yarns for shed levelling or on movements of the cloth, no pile yarns are pulled back out of the cloth, so undoing the loop formation. The brackets pointing with their narrow side in weaving direction hinder the pile warp yam running only slightly. The brackets allow the spring elements to be arranged under the warp yarns, so as make them readily accessible for an operator. The leaf spring assemblies allow uniform adjustment of the necessary spring forces, wherein an at least approximately linear spring characteristic is provided. The preferably pre-tensioned spring elements are deflected in accordance with changes in tension. The spring forces may be adjusted by means of the number of leaf springs in the leaf spring assemblies.
Further features and advantages of the invention are revealed by the following description of the embodiment illustrated in the drawings.

Fig. 1: shows a schematic representation of a terry loom according to the invention,
Fig. 2: is a perspective view of a mounting arrangement for the pile warp yarn backrest,
Fig. 3: shows a detail of Fig. 2 on an enlarged scale and viewed in the direction of arrow III in Fig. 2,
Fig. 4: is a side view of the pile warp backrest and its mounting arrangement,
Fig. 5: is a perspective view, on a somewhat smaller scale, of the pile warp backrest with a device for measuring warp tension and

The terry loom illustrated schematically in Fig. 1 has a warp beam 10 with a ground warp 11 and a warp beam 12 with a pile warp 13. The ground warp 11 is deflected over a backrest 14 into the weaving plane. The pile warp 13 runs over a deflector 15 to its own backrest 16 and thence likewise into the weaving plane. As is clear from Fig. 1, the deflector 15 is arranged in such a way that the pile warp 13 is wrapped round the backrest 16 over an angle of approximately 150°, wherein the pile warp 13 runs approximately parallel to the weaving plane from the deflector 15 to the backrest 16 and from the backrest 16 to the device 17 means. Upstream of the backrest 14 of the ground warp 11 there is arranged a stationary deflection roll 44, which is rotatable about a shaft 40. In this way, the warp yarns 11A run from a full warp beam 10 and the warp yarns 11B from an almost empty warp beam 10 substantially in the same way to the backrest 14. For the same reason, a stationary deflection roll 45 is arranged upstream of the deflector 15, such that the warp yarns 13A of the pile warp 13 and the warp yarns 13B, which come from a full or almost empty warp beam 12, run in substantially the same way to the deflector 15.
Weft yarns are inserted into the successively formed sheds. The device provided for inserting weft yarns is for example a device as is conventionally used for air-jet looms. This has two main blowing nozzles arranged one behind the other and next to the shed and a row of relay nozzles, which are arranged on a sley 18 and whose blowing direction is directed towards a weft insertion channel of a reed 19. The reed 19, which is fitted on the sley 18 and swivels therewith, brings the inserted weft yarns up to a beat-up line. At this beat-up line, the inserted weft yarns are tied up by means of the warp yarns when the shed is changed, i.e. a number of warp yarns change from the upper position into the lower position and a number of warp yarns change from the lower position into the upper position.
The cloth 20 formed in this way is drawn off by means of a draw-off roller 21, for example a sand roller or needle beam, and wound onto a cloth beam 22. A breast beam 23 and two deflectors 24, 25 are arranged upstream of the draw-off roller 21 in the draw-off direction.
In this embodiment, the backrest 14 for the ground warp 11 may be swivelled about a shaft 40 parallel thereto by means of levers 26 holding its two ends. The breast beam 23 is held by means of two levers 27 acting on its end, said levers being swivellable about the axis of the deflector 24. The levers 26, 27 are acted upon by transmission bars 28, 29, whose respective other ends are coupled to a swivel arm 30. On either side of the cloth width, such swivel arms 30 are arranged non-rotatably on a shaft which may be swivelled to and fro by means of a geared motor 31, preferably a stepping motor. By means of this drive system consisting of the levers 26, 27, the transmission bars 28, 29, the swivel arms 30 and the drive motor 31, the backrest 14 for the ground warp 11 and the breast beam 23 may be moved to and fro in the same direction. During this to-and-fro motion, the cloth 20 is displaced relative to the reed 19, which may be swivelled between a rear position and a front position. In the process, the distance from the fell of the cloth 20 to the beat-up line of the reed 19 is varied. The lever 26, which is rotatable about the shaft 40 and bears the backrest 14, comprises an arm 46, which is held by a spring element 47 which is supported on the frame of the loom.
The backrest 16, the design of which will be explained in greater detail with reference to Figs. 2 and 3, is not provided with a drive. However, it is held resiliently substantially in the weaving direction, such that it can follow satisfactorily the movement of the cloth 20. If, for example, provision is made for the cloth 20 to be moved away from the reed 19, to the left in Fig. 1, after beat-up of a weft yarn to the fell, the next weft yarns are not beaten up to the fell, but rather remain at a distance therefrom. If, for example, the cloth 20 with its fell is then moved back closer to the reed 19 after two to four or more picks, by moving backrest 14 and breast beam 23 accordingly (to the right in Fig. 1), the reed 19 moves the last inserted weft yarns up to the fell on the next beat-up. In the process, these weft yarns slide along the warp yarns of the ground warp 11, which is relatively tightly tensioned. The warp yarns of the pile warp 13 are less tightly tensioned, such that the weft yarns carry these warp yarns of the pile warp 13 with them during the beat-up movement. In this way, the warp yarns of the pile warp 13 are formed into loops. If the backrest 14 and breast beam 23 are then swivelled again by means of the drive motor 31 in such a way that the fell of the cloth 20 moves away from the reed 19, the warp yarns of the pile warp 13 are tightened. They then draw the backrest 16 in the direction of the reed 19, wherein the resilient mounting of the backrest 16 yields in such a way that the previously formed loops are not pulled back out of the cloth 20 as the cloth 20 is displaced. The deflector 15 assists in this resilient function, said deflector being to this end of elastic, for example rubber-elastic, construction. The deflector 15 preferably takes the form of a so-called oscillating sheet shaft, i.e. a cylindrically curved spring steel sheet whose overlapping edges are attached to a bar. In a modified embodiment, the deflector 15 is mounted rotatably and/or provided with a rotary drive. This type of deflector 15 is advantageous as an addition to the backrest 16, allowing shed levelling and more reliably ensuring a terry weave.
The resilient mounting arrangement of the backrest 16 for the pile warp 13 is illustrated in detail in Figs. 2 and 3. The backrest 16 is a tubular bar, which is held by means of narrow brackets 32 each comprising a semicircular recess. The brackets 32 are attached with T-shaped holders 33 to the upper ends of leaf spring assemblies 34 by means of screws 41. The lower ends of the leaf spring assemblies are fixed by means of screws 42 to a holding block 35, which is in turn attached by means of screws 43 to a holding rail 36. The holding rail 36 is fixed to a crossbar 37, which takes the form of a square tube. The holding rail 36 is provided with an undercut groove 38, in which nuts are guided, into which screws 43 are screwed, which hold the holding blocks 35 in displaceable manner. The holding rail 36 is attached to the crossbar 37 by means of screws 48. The holders 33 and the brackets 32 are connected together by means of screws 49.
As is clear from Fig. 2, there is provided a plurality of leaf spring assemblies 34 distributed evenly over the cloth width, these holding the backrest 16 in such a way that it yields in the warp direction, wherein the leaf spring assemblies 34 bend accordingly.
As is further illustrated in Fig. 2, a warp stop motion 39 is arranged downstream of the backrest 16 of the pile warp 13, such that the warp yarns of the pile warp 13 are monitored for warp breakage separately from the warp yarns of the ground warp 11. The warp yarns of the ground warp 11 have their own warp stop motion assigned to them.
The leaf spring assemblies 34 extend substantially vertically, i.e. substantially perpendicularly to the weaving plane or warp direction, such that the backrest 16 is held so as to be resilient parallel to the weaving plane or warp direction. The leaf spring assemblies 34 are arranged under the pile warp 13 and ground warp 11, the brackets 32 projecting therethrough.
As is clear in particular from Fig. 4, the brackets 32 are provided with borders 50. A somewhat more than semicylindrical receptacle 60 serves in mounting the backrest 16, which may be clipped into this receptacle 60. The receptacle 60 is made of a vibration-reducing, wear-resistant material. In this way, it is ensured on the one hand that the brackets 32 are protected against wear and on the other hand that vibrations of the backrest 16 are not fully transmitted to the brackets 32, so suppressing noise. The brackets 32 themselves are arranged with their flat sides parallel to the warp yarns of the ground warp 11 and the pile warp 13, such that they hinder warp yam running only slightly. The edges of the narrow sides are protected by the border 50.
Fig. 5 shows an embodiment in which the crossbar may be rotated together with the spring assemblies 34, the brackets 32 and the backrest 16 about an axis extending parallel to the axis of the backrest 16. To this end, the crossbar 37 is provided at both ends with journals 51, which are mounted in the machine frame by means of bearings 52. The crossbar 37 is provided with a holder 55, to which a bar 56 is attached by means of a screw 58. The bar 56 is attached to a holder 54 by means of a screw. The holder 54 comprises a force transducer, with which the forces exerted by the warp yarns of the pile warp 13 on the backrest 16 may be detected. In the exemplary embodiment illustrated, the force transducer 53 is adjustable by means of a drive 59, for example a linear motor, such that the crossbar 37 may be swivelled and thus the force may be adjusted with which the warp yarns of the pile warp are tensioned. Pretensioning of the leaf spring assemblies 34 is also adjusted thereby.
The number of brackets 32 and thus of spring assemblies may be selected as a function of the width, as may their spacing over the width. The spring stiffness of the leaf spring assemblies 34 is set to a lower value, for example half the value, at the two ends of the backrest. This may be achieved simply by reducing the number of leaf springs in the leaf spring assemblies 34 accordingly. In the event of a change in cloth width, the number of brackets 32 and/or the number of leaf springs in the leaf spring assemblies 34 may be suitably adjusted.
In a further development of the invention, a lubricant is appropriately provided between the leaf springs of the leaf spring assemblies 34.
In a further embodiment the crossbar 37 is provided with a stopper elements The stopper element of this embodiment is a leaf spring plate which faces by a bent end the leaf spring assembly 34. The plate is mounted on the crossbar 37 by means of bolts and seal rings . The bolts which are arranged in a row extending in longitudinal direction of the crossbar 37 extend through slits of the plate. The slits are directed perpendicular to the longitudinal direction of the crossbar 37 and the plate so that the plate is adjustable in a direction with respect to the leaf spring assembly 34.
When the leaf spring assembly 34 comes into contact with the stopper element the movement of the leaf spring assembly 34 is limited. Also the spring characteristic or the stiffness of the leaf spring is increased. Such a stopper element is of advantage if the tension in the warp yarns 13 is substantially increased.
The backrest 16 according to the invention of the pile warp 13, which is held so as to be resilient substantially in the weaving direction, may be used in any type of terry loom. For example, said backrest may also be used in a terry loom in which the terry cloth is produced by means of sley adjustment. Such a terry loom with sley adjustment is described in detail for example in EP 1 201 804 A1 . It comprises a stationarily arranged breast beam.
It goes without saying that the invention is not restricted to a terry loom in which the weft yarns are inserted by means of air jets. It may also readily be applied to rapier looms, projectile looms, shuttle looms, gripper shuttle looms, water jet looms or any other type of loom. The backrest according to the invention, which is resilient in the weaving direction, may also be retrofitted to any type of loom, such that said loom may be accordingly upgraded. The backrest arrangement of the present invention is especially useful for pile warp yarns of a loom because it is suitable for loosely or less tightly tensioned warp yarns of a loom.
The invention is not restricted to the exemplary embodiment illustrated. Other drives may also be readily provided for moving backrest 14 and breast beam 23 to and fro. In particular, cam drives may be provided, which derive their movement from a main shaft of the loom.

Claims

A terry loom with devices for supplying a ground warp (11) and a pile warp (13), with a backrest (14) for the ground warp and a backrest (16) for the pile warp (13), which backrest (16) is held resiliently substantially in weaving direction, with a shedding device (17), with a device for inserting weft yarns, with a device (18, 19) for beating up the weft yarns and with a device (21, 23, 24, 25) for drawing off cloth (20), which comprises a breast beam (23), characterised in that
the backrest (16), which has the form of a bar, is mounted on spring elements by means of brackets (32) pointing with their narrow side in weaving direction, which spring elements are in the form of a plurality of leaf spring assemblies (34), which are distributed over the cloth width and oriented substantially perpendicularly to the weaving direction.
A terry loom according to claim 1, characterised in that a deflecting element (15) is arranged upstream of the backrest (16).
A terry loom according to claim 1 or 2, characterised in that the backrest (16) for the pile warp (13) and the deflecting element (15) are arranged in such a way that the pile warp yarns run to and from the backrest (16) approximately parallel to the weaving direction.
A terry loom according to any one of claims 1 to 3, characterised in that the pile warp yarns have their own warp stop motion (39) assigned to them downstream of their backrest (16).
A terry loom according to claim 1, characterised in that the backrest (16) for the pile warp (13) is mounted rotatably in the brackets (32).
A terry loom according to one of claims 1 to 5, characterised in that the backrest (14) for the ground warp (11) and the breast beam (23) may be moved to and fro in the warp direction by means of drives (26, 27, 28).
A terry loom according to one of claims 1 to 6, characterised in that the spring elements (34) holding the brackets (32) are arranged under the warp yarns of the pile warp (13).
A terry loom according to any one of claims 1 to 7, characterised in that the backrest (16) for the pile warp (13) is held by means of a holding device (51 to 59), which comprises devices for detecting the tension of the warp yarns of the pile warp (13).
A terry loom according to claim 8, characterised in that the backrest (16) for the pile warp (13) is adjustable by means of a drive (59).
Backrest arrangement for a weaving machine, characterised by a backrest (16) in the form of a bar which is mounted on spring elements by means of brackets (32) pointing with their narrow sides in weaving direction, which spring elements are in the form of leaf spring assemblies (34) which are distributed over the cloth width and oriented substantially perpendicularly to the weaving direction.
Backrest arrangement according to claim 10, characterised in that the backrest (16) is rotatably mounted in the brackets (32).
Backrest arrangement according to claim 10 or 11, characterised by a device (59) for adjusting the position of the backrest (16).
Backrest arrangement according to on of claims 10 to 12, characterised by a stopper element (61) for limiting the movement of the spring assembly (34).