EP1033427A1

EP1033427A1 - Adjustable fabric support for weaving looms

Info

Publication number: EP1033427A1
Application number: EP00103814A
Authority: EP
Inventors: Giuseppe Casarotto
Original assignee: NUOVA VAMATEX SpA; Promatech SpA; Vamatex Nuova SpA
Current assignee: Promatech SpA
Priority date: 1999-02-24
Filing date: 2000-02-23
Publication date: 2000-09-06
Anticipated expiration: 2020-02-23
Also published as: DE60030609T2; ATE339536T1; DE60030609D1; ITMI990372A1; EP1033427B1; ES2267424T3; IT1308631B1

Abstract

The present invention relates to a fabric support for weaving looms, of the type comprising a main body (2) and a lip (1a) for supporting the fabric (T) and apt to co-operate with a template (4) for tensioning the fabric, which is mounted in an adjustable manner on a base element (30) by means of a rotoidal guide (6) which allows adjustment thereof according to a rotational displacement.

Description

The present invention relates to a fabric support for weaving looms. In particular, it relates to an improved fabric support which allows easy adjustment of the geometrical form of the warp shed.
It is known that, in weaving looms, after arranging in position the warp yarns, it is necessary to ensure the correct geometrical form or configuration of the warp shed, by arranging the various components in a suitable relationship with each other, so as to obtain the desired working equilibrium between the weaving machine and the said warp yarns depending on the fabric which is to be produced.
More specifically, it is fairly crucial - both during set-up of the loom and during subsequent loom start-up operations - to achieve the correct relative arrangement of the fabric support and the yarn carrier, the templates, the cutters, the insertion device, etc. Normally, the operation involving adjustment of these components requires time, patience and a certain degree of skill since, owing to the functional relationship between the positions of the various components, it is difficult to achieve convergence towards the desired machine set-up, said convergence being achieved only by means of subsequent corrective operations.
In fact, adjustment of the warp shed - which is determined also depending on the transverse dimension of the weft-carrying gripper - may be achieved by adjusting the positions of the fabric support and the yarn carriers which, in turn, affect a series of subsequent adjustments (position of the templates, the cutters, the insertion device, the guide hooks of the grippers, etc.): therefore, the convergence towards the optimum operating parameters is somewhat laborious.
In particular, in the following description certain specific interactive relationships which are particularly relevant for the purposes of the present invention will be highlighted.
As can be seen in Fig. 1 - which shows a side elevation view of the fabric support zone in a loom according to the prior art - the fabric support comprises a so-called bracket plate 1, which is located underneath templates 4, and a base portion 2, which is fixed by means of rectilinear guides to the fixed frame 3 of the weaving loom.
In view of its specific geometrical form, whenever the fabric support is displaced along its rectilinear guides, its distance with respect to the templates, the reed and the guide hooks of the weft-carrying grippers is modified significantly. It is therefore necessary to adjust also the position of all these components in order to re-establish the correct working relationship. As is known, the correct tensioning of the fabric is determined, among other things, by the relative distance of the fabric support and the templates. In fact, each template 4 exerts a certain pressure on the fabric, against the support action of a lip 1a of the bracket plate 1 and a fabric deviating device 5: it is therefore obvious that the distance between the template 4 and the bracket plate 1 determines the degree of pressure exerted on the fabric and therefore defines one of the operating parameters.
Similarly, the variation in the distance between the reed and the lip of the fabric support, in most cases, is undesirable and therefore it is necessary to perform other adjustments in order to restore also the correct distance between these two components.
The same applies to the distance between the fabric support and the guide hooks of the weft-carrying grippers (where provided), which must not fall below a certain threshold value, in order to avoid interference.
These corrective operations, as can be understood, are anything but simple and require delicate adjustments, both of the position of the fabric support and of the other abovementioned components, which result in deviations of a not insignificant nature (of the order of a few millimetres). Also, in the case where the rectilinear guide define a translation of the fabric support such that the distance thereof from the reed remains unvaried (substantially vertical translation), the difficulties associated with relative positioning of the fabric support, templates and, in certain cases, guide hooks remain.
The object of the present invention is to solve the problems associated with adjustment of these components by providing a fabric support which, on the one hand, allows simplification of the operation involving adjustment of the geometrical form of the warp shed and, on the other hand, may be displaced without affecting significantly the relationship between its own working position and that of the templates, the reed and the guide hooks.
These objects are achieved by means of a fabric support device for weaving looms - of the type comprising a fabric supporting lip designed to co-operate with a template for tensioning the fabric - which is mounted in an adjustable manner on a base element by means of a "rotoidal" guide which allows adjustment thereof according to a rotational displacement.
Other aspects of the invention are illustrated in the accompanying claims.
Further characteristic features and advantages of the device according to the invention will emerge, however, more clearly from the detailed description which follows of a preferred embodiment thereof, provided by way of an example and illustrated in the accompanying drawings, in which:
Fig. 1, as already mentioned, shows a side elevation view, with parts removed, of the zone for forming the fabric in a loom using a fabric support of the prior art;
Fig. 2 is a perspective sectional view of a fabric support according to the invention;
Fig. 3A is a schematic perspective view of the zone of the fabric support in a weaving loom according to the invention;
Figs. 3B and 3C are schematic side elevation views which illustrate the interaction between the fabric support according to the invention, a template, the reed and one of the guide hooks; and
Figs. 4A-4C are side elevation views, with parts removed, which illustrate the interaction between the reed, one of the guide hooks and the fabric support according to the invention, for different positions assumed by the latter.
As can be seen in Fig. 2, the fabric support is composed, in a manner known per se, of a bracket plate 1 and a root portion 2 joined, in an adjustable manner, to the weaving loom (not shown).
The bracket plate 1, together with the root portion 2, preferably consist of a profiled section which is slightly curved in the transverse direction and extends over the whole width of the loom and which has a longitudinal lip 1a, gently filleted, intended to support the fabric T supplied from the weaving zone.
Each end of the loom is provided with templates 4 - not described in detail here since they are widely known to persons skilled in the art - which are arranged with their longitudinal axis according to the width of the loom and which are designed to keep the fabric extended along its width by exerting a certain pressure thereon.
According to the invention, the fabric support is mounted on a support base 30 by means of a rotoidal adjusting guide 6. In this context, the definition "rotoidal guide" is intended to indicate a guide which is apt to allow a rotational movement of the fabric support about a suitably located axis of rotation.
In particular, in the embodiment shown in the accompanying figures, the root portion 2 of the fabric support has a surface of revolution which is engaged with a corresponding surface of revolution of the support base 30. The root portion 2 and the support base 30 are then joined and locked together by means of fixing means, for example by means of bolts 7 which are inserted into eyelets 8 correspondingly formed on the root portion 2 or on the support base 30, preferably in the support base 30.
According to a preferred embodiment of the invention, the axis of rotation defined by the rotoidal guide 6 coincides with the eccentric axis of rotation 4a of the template 4.
Sliding in the rotoidal guide 6 may be accomplished according to separate and well-defined positions or may be allowed with continuity. Preferably, reference notches (not shown) are provided on one or both the surfaces of revolution of the rotoidal guide 6, apt to allow easy visual adjustment by the operator.
The fabric deviating device 5 may be formed integral with the fabric support or may be fixed to the latter by means of suitable joining means which may be adjustable. Preferably the fabric deviating device 5 is fixed, in an adjustable manner, to the support base 30, as can be seen in Figs. 3A-3C.
In order to perform adjustment of the fabric support, it is sufficient to slacken the fixing means 7, determine the desired relative position of the fabric support and the support base 30, if necessary determine a new position also for the fabric deviating device 5 and then tighten again the fixing means.
Owing to the rotoidal guide 6, the displacement of the fabric support does not modify substantially the relative position of the bracket plate 1 with respect to the template 4 and the guide hooks 10, advantageously being inserted between these two components and the reed 9. Therefore, in most of the adjustments, no modification of the position of the template 4 is required.
Furthermore, advantageously, the distance between the lip 1a and the reed 9 of the loom, which is indicated by X₁ and X₂ in Figs. 3B and 3C, respectively, varies in an absolutely negligible manner for small angular displacements of the fabric support (as occurs with most of the adjustments).
It is therefore obvious that the invention fully achieves the objects mentioned in the introduction. In fact, the adjustment of geometrical form of the warp shed may be achieved very simply by acting only on the means for fixing the fabric support.
Moreover, the rotoidal guide allows adjustment of the fabric support to be performed independently of that of the templates 4 and the guide hooks 10, making it much simpler to achieve convergence towards the desired geometry.
Finally, in the case of small angles of rotation, the rotoidal guide allows the desired adjustment of the fabric support to be performed without significant changes occurring in the distance from the lip of the breast-plate with respect to the reed of the loom.
It is understood, however, that the invention is not limited to the particular configuration illustrated above, which represents only a non-limiting example of the scope of the invention, and that numerous variations are possible within the reach of skilled of the art.
In particular, fixing means may vary widely, but are all within the technical competence of persons skilled in the art.
Moreover, the rotoidal guide has been shown in a basic and simple configuration, but could assume different forms (for example a helical connection between the root element and a translatable actuating member) and could be provided with other means which make it easier to be operated (for example, guide ribs, sliding or rolling bearings, other reference and locating members), without thereby departing from the scope of protection of the invention.

Claims

Fabric support for weaving looms of the type comprising a main body (2) and a lip (1a) supporting the fabric (T) and apt to co-operate with a template (4) for tensioning the fabric, characterized in that it is mounted in an adjustable manner on a base element (30) by means of a rotoidal guide (6) which allows adjustment thereof according to a rotational displacement.
Fabric support according to Claim 1, in which said rotational displacement occurs about an axis of rotation which is located in a position corresponding to the axis of rotation (4a) of said template (4).
Fabric support according to Claim 1 or Claim 2, in which said rotoidal guide comprises two engaged surfaces of revolution, one being located on the fabric support and the other on said base element (30).
Fabric support according to Claim 3, in which said rotoidal guide is lockeable by means of adjustable fixing means (7, 8).
Fabric support according to Claim 4, in which said adjustable fixing means are bolts (7) which are inserted into eyelets (8) formed on the fabric support or on the base element (30).
Fabric support according to Claim 5, in which one locking end of said bolts is engaged in an undercut surface in said main body (2) of said fabric support.
Fabric support according to any one of the preceding claims, in which reference notches are provided on the fabric support or on the base element which are apt to show relative positioning thereof.
Fabric support according to any one of the preceding claims, in which said base element (30) is rigidly joined to the frame of the weaving loom.
Weaving loom incorporating a fabric support according to any one of the preceding claims.