Patent GB-934181-A (GB)
Title: Automatic brake for a prime mover
IPC: H02K7/12
Filed: 1959-11-05
Abstract: 934,181. Friction brakes. ADAM BAUMULLER G.m.b.H. Nov. 5, 1959 [Nov. 8, 1958; April 25, 1959; June 24, 1959], No. 37500/59. Class 103 (1). [Also in Groups XIII, XXIV and XXXV] A brake for a prime mover (for example an electric motor) is applied when the driving force ceases and is automatically disengaged when the driving force becomes effective, the drive shaft of the prime mover being connected to a driven shaft by a clutch coupling including two clutch members having interengaging projections co-operating with inclined cam surfaces, one clutch member being secured to the drive shaft and rotatable about an angle relative to a second clutch member mounted on the driven shaft against the action of an opposing force acting upon the second clutch member such that this relative movement effects disengagement of the brake. In the embodiment disclosed in Fig. 1, a three-phase squirrel-cage induction motor 1 is provided with a rotor 6 connected to a hollow driving shaft 7 to which is connected a flange 15 provided with a cam ring 18 which is adapted to co-operate with another cam ring 18 formed on another flange 21 which is welded to a socket 23 which is axially slidable but non-rotatable on a driven shaft 12. A brake member 26 is positioned on the outer surface of the socket 23 and a lining 27 secured to the member 26 co-operates with an inclined raising surface 28 of the motor bearing plate 3 under the influence of spring members 33 and 36 when the motor is deenergized. As soon as the motor is energized, the rotor 6 will start to rotate and attempt to take along flange 15 which is rigidly secured to the hollow shaft 7 and cam ring 18 thereon. However, since at the time when the motor is energized the brake is still active, the cam ring 18 which is rigidly secured to flange 21 cannot be taken along immediately and will therefore at first be turned. Both cam rings 18 have inclined cam surfaces 38 and 39 which interact to produce an axial displacement of the cam ring 18 on flange 21 against the action of springs 33 and 36 and thus an axial displacement of brake member 26 with brake lining 27 thereon to effect disengagement of the brake. If the current is disconnected, there would be no longer any driving force and coil spring 33 will then immediately press bushing 23 and brake member 26 with brake lining 27 thereon against the brake surface 28 so that the driven shaft 12 will be stopped. A nut 29 is screwed on to the end of the bushing 23 in order to adjust the brake member 26 when the friction lining 27 becomes worn. The interacting cam rings 18 may be replaced by ball and ramp mechanisms which effect axial movement of the socket 23 against the force of spring 33 and 36 to disengage the brake. In an alternative embodiment shown in Fig. 15, a hollow drive shaft 91 provided with a flange 97 is rotated when the electric motor is switched on, whereby rollers 101 move upon and along inclined surfaces 102 provided on segments 103 which embedded within a resilient ring 104 provided in the movable brake member 108 in order to exert an axial force against springs 113 and 122 to disengage the friction linings 110 on brake member 108 to release the brake. The movable brake member 108 is provided with ribs 126 for ventilating the motor. In the embodiment shown in Fig. 22 an electric motor is provided with a driving connection through the spinning drum 144 of a spin drier, not shown, the single phase motor 153 is provided with a starting condenser 161 which will deliver to the motor 153 the amount of electricity stored up therein in the form of a counter-current impulse whereby a counter-torque will be produced in the motor when the motor is switched off. When the motor is energized the driving shaft 157 rotates to urge three driving studs 172 integral with a ring 170 which is secured to the driving shaft 157 such that the studs 172 interact with cam surfaces 173 on a braking flange plate 148 connected to the spin drier drum 144 to lift the movable brake member 148 and hollow shaft 147 as well as the spinning drum 144 to disengage the brake 149. As soon as the motor 153 is switched off the brake is applied.