Thread tension regulation in a thread brake device and method in a textile processing machine

#This application is based on and claims the priority under 35 U.S.C. §119 of German Patent Application 102 18 059.8, filed on Apr. 23, 2002, the entire disclosure of which is incorporated herein by reference.

#The invention relates to an apparatus and a method for regulating the thread tension in connection with selective braking of the thread in a textile processing machine, especially in a weaving loom.

#Such devices pertinent to the general background of the present invention, often known as thread brakes, are well known in many different conventional configurations and arrangements, and are typically used, for example, as weft thread brakes in weaving looms.

#In order that the invention may be clearly understood, it will now be described in detail in connection with example embodiments thereof, with reference to the accompanying drawings, wherein:

#FIG. 1 is a simplified schematic diagram of a first embodiment of a regulated thread brake arrangement according to the invention; and

#FIG. 2 is a simplified schematic diagram of a second embodiment of a regulated thread brake arrangement according to the invention.

#FIG. 1 schematically shows a thread brake arrangement 1 according to the invention, as it may be used for braking a weft thread in a weaving loom. The thread 2 is guided and extends in a threading running or feed direction 3 along a straight linear thread travel path through the thread brake arrangement 1. The thread brake arrangement 1 includes two lamellar brake elements 4 and 5, for example thin metal sheets or lamellae 4 and 5, which are elastically flexible and elastically pressed against one another, with the thread 2 received running therebetween. The thread brake arrangement 1 further includes two opposed actuators or operating elements 8 and 9 that selectively act on the two lamellar brake elements 4 and 5 in opposite directions as shown by the double-headed arrows, to apply a controllable actuating displacement and/or force to the brake elements 4 and 5, so as to exert a controllable braking force B via the brake elements 4 and 5 onto the thread 2.

#When the thread brake is open, i.e. when no braking force is to be exerted on the thread 2, and therefore the brake elements 4 and 5 are moved maximally away from each other by the actuators 8 and 9, the thread 2 runs unhindered and without contact between the brake elements 4 and 5 in the thread running or feed direction 3. In this condition, no braking force B is applied to the thread 2, and the thread 2 also does not undergo any deflection out of its linear thread path along the thread feed direction 3, through the thread brake arrangement 1.

#On the other hand, when a selected thread tension is required in the thread 2, the brake elements 4 and 5 are moved into contact with each other and pressed against each other by the controlled actuating of the actuators 8 and 9, so as to exert the braking force B onto the thread 2 between the brake elements 4 and 5, whereby a corresponding thread tension force F is caused in the thread 2. As a result, a counter-force or reaction force of F/2 is exerted by the thread 2 reactively back onto each one of the brake elements 4 and 5, respectively along or parallel to the thread running direction 3.