1302733 Positive clutches MINNESOTA MINING & MFG CO 9 March 1970 [10 March 1969] 11233/70 Headings F2C and F2E A uni- or bi-directional clutch or brake 20 comprises a pair of spaced discs 10, 12 carrying short stiff straight fibres 14 which extend at an angle less than 45 degrees from the surfaces of the disc and at right angles to the radial line passing through their points of attachment, the discs being moved axially for engagement of the interdigitating fibres. The fibres are preferably 50 denier nylon; 0À150 inches long; extend at an angle between 15-95 degrees; and are distributed at a density of 8,000 fibres /sq. inch. For unidirections clutches or brakes the fibres on each disc extend in the same circumferential direction around the discs. For bi-directional clutches or brakes, the fibres are arranged in circular strips about the common rotational axis, with the fibres in adjacent strips extending in opposite circumferential directions. The fibres are bonded to a flexible fabric backing 16, e.g. open web cotton, secured to the discs. Again, Fig. 5 (not shown), a brake (26) is fast with the rotor shaft (38) of an electric motor (30) in which the rotor (36) is vertical and not centred lengthwise via the stator (34). With the motor de-energized, the rotor, and its shaft rest vertically on the motor casing (32), and the brake is engaged. On energizing the motor the rotor is centred in its stator and the upper brake discs is moved out of engagement with the lower.