[0001] The present invention relates to an improved thread carrier for weaving looms.
[0002] As known, one of the problems which the designers of looms have to face is that of
an appropriate positioning of the thread carrier and of the torsion bar associated
thereto, in order to extend the signals produced by the variations of tension in the
threads to the full height of the loom.
[0003] The current trend to increase the width of weaving machines, to obtain wider fabrics,
causes the hollow metal cylinder forming the thread carrier in looms to be subjected
to increasingly higher stresses. It is hence necessary to increase the diameter of
said cylinder, the diameter of the torsion bar and the load to be opposed: this means
an increase of the overall volume of said unit, with serious inconveniences for the
planning of the loom.
[0004] The object of the present invention is to provide an improved arrangement of the
thread carrier-torsion bar unit and of the respective contrast means in a weaving
loom, reducing the overall dimensions of the thread carrier and of the torsion bar,
as well as the dimensions of the elastic contrast elements, without any transmissions
and allowing the thread carrier to rotate about its own axis.
[0005] This is obtained, according to the invention, by arranging the torsion bar inside
the thread carrier hollow cylinder, parallel to and in an eccentric position in respect
of said cylinder, two end supports connecting the cylinder to the bar by means of
a clamp provided between the support and the bar and a clamp and bearing provided
between the support and the cylinder.
[0006] The invention will be described hereinafter, by mere way of example, with reference
to the accompanying drawing, which shows a preferred embodiment thereof and in which:
Fig. 1 is a head view - with some parts in section and other parts removed - of the
arrangement according to the present invention; and
Fig. 2 is a scrap view, from the top and at one end, of the arrangement of figure
1.
[0007] With reference to the drawing, the thread carrier 1 of the invention consists of
a hollow metal cylinder 2, which is mounted at each end onto a support 3 by way of
a bearing 4. The cylinder 2 may thus rotate on the bearing 4 in respect of the support
3, which is besides provided with a clamp 5, normally loose and by tightening which
the cylinder 2 can be stopped from rotating.
[0008] The support 3 is made so as to support also the torsion bar 6, which is housed inside
the hollow cylinder 2 in an eccentric position, namely with its axis 6' parallel to
the axis 2' of the cylinder 2 but separate therefrom, as clearly evidenced in the
figures of the drawing. The bar 6 is locked to the support 3 by a second clamp 7 of
said support, normally tightened, and its end is mounted in a conventional way onto
the frame 8 of the loom.
[0009] Reference 9 indicates contrast spring means acting on the thread carrier-torsion
bar unit through a lever 10 provided with a toothing 11 for hooking the spring 9 into
a plurality of positions, to which correspond variable contrast actions of said spring
9.
[0010] With the illustrated arrangement, the size of the unit comprising the thread carrier
and the torsion bar therefor is notably reduced, the dimensions being - as clearly
evident from the above description and drawing - simply those of the thread carrier
(within whose cylinder the torsion bar is housed). Furthermore, in said arrangement,
the point in which the resultant of the warp tensions is applied is very close to
the axis of the torsion bar, which forms the fulcrum of application thereof; the torque
being generated by said resultant is thereby small (having an arm six or seven times
smaller than that of the conventional arrangements), with the considerable advantage
of allowing to use a contrast system being less stressed so reducing the dimensions
even further.
1) Thread carrier for weaving looms, characterized in that the torsion bar associated
thereto is positioned inside the hollow cylinder of the thread carrier itself, with
its own axis parallel to but separate from the axis of said cylinder, two end supports
connecting the cylinder to the torsion bar by means of a clamp provided between the
support and the bar and a clamp and bearing provided between the support and the cylinder.
