| 摘要 |
906,244. Yarn tensioning device. ONDERZOEKINGSINSTITUUT RESEARCH N.V. May 24, 1960 [May 25, 1959], No. 18315/60. Class 120 (2). In a thread or yarn brake which is suitable for a yarn doubling device and in which a braking roller 24 has fast on it a magnetic hysteresis disc 47 for co-operation with a crown magnet 41 coaxially arranged with its poles near to and facing the disc and a pressure roller 25 co-operating with the braking roller, the pressure roller is rotatably mounted on the free end of an arm 26 pivotally mounted on the magnet support or housing 21, the axis of rotation of the pressure roller being within the compass of the magnet. Yarn enters the device through the eyelet 8 and passes via a tubular guide 38 and a guiding funnel 36 to the braking roller 24 on which it is nipped by the pressure roller 25. The yarn then passes about the braking roller 24 through an angle which is preferably greater than 270 degrees before leaving the roller and passing via the guide pulley 39, out of the device. Provision is made for the adjustment of the distance between the hysteresis disc and the magnet poles and also for the adjustment of the spring force urging the arm 26 carrying the pressure roller 25 toward the braking roller. The pressure roller and/or the braking roller may be formed with a cylindrical centre portion and frusto-conical outwardly tapering outer portions, the apex angle of which is about 1 degree and the covers for the rollers may be made from a rubber-like modification of polyurethane. The space between the poles of the magnet is filled with a synthetic resin to prevent accumulation of dust. |
