Patent GB-1293822-A (GB)
Title: Electromagnetic brake or clutch devices
IPC: F16D27/06
Filed: 1970-04-21
Abstract: 1293822 Electromagnetic clutches or brakes; wear-compensating MASCHINENFABRIK HANS LENZE KG 21 April 1970 [21 April 1969 (2)] 19133/70 Headings F2C and F2E In a spring-and-electromagnetically-operated clutch or brake mechanism having a rotary member 5, friction elements (some of the stack of laminµ 6) mounted on it, a component 4 axially displaceable towards and away from the friction elements for engagement and disengagement respectively of the mechanism, pressure means (bolts 9 and ring 10) and an adjustment device 12, 13, 15, to compensate for wear of the friction faces, an axially-stationary component 1 is disposed adjacent the component 4, and in the absence of wear all the bolts 9 are moved equal distances to left and right relative to component 1 on engagement and disengagement, but when wear has occurred they are moved a further small distance to the left to a new position. In the clutch of Fig. 1 a clutch housing 8 is secured at 7 to a magnetic core 1 which is keyed to a driving shaft (not illustrated), the housing carrying the outer laminµ of a lamina stack 6; the inner laminµ are keyed to a rotor 5 which is in turn keyed to the driven shaft (not illustrated). A solenoid 2 in the magnetic core 1 is fed through slip-rings 3 and co-operates with an armature 4 supported from the core 1 by bolts 17. Pressure bolts 9 (only one shown) are slidably mounted in the core 1 and each engages a pressure ring 10 which may thus be brought into or out of engagement with the end lamina of stack 6. Each bolt also has mounted on it two resilient locking elements 12 which may be Belleville-type washers and which engage the bolt 9 firmly in one direction only; these are disposed in a cavity 11 of armature 4; the bolt has a further locking element 13 of the same kind disposed in a cavity 14 in magnetic core 1. Cavity 14 is closed by a disc 15 and has a depth equal to the axial length of element 13 plus the normal length of the armature stroke. A return spring 16 surrounds each bolt 9. In operation, the clutch is engaged from the disengaged position shown by energizing solenoid 2, whereupon armature 4 is attracted and carries with it to the left, by locking elements 12, the bolt 9. The bolt 9 in turn conveys element 13 into contact with disc 15 and, through pressure-ring 10, compresses the laminµ. If wear has occurred, bolt 9 is forced by further movement of the armature to take up the slack, thereby created in stack 6, and thus is moved by this amount through element 13, which is retained by disc 15. On de-energization of the solenoid, the bolt assembly is moved to the right by expansion of stack 6 and by spring 16 until element 13 reaches the base of cavity 14, whereupon bolt 9 is arrested. Further movement of armature 4 to its original position by spring 16 causes elements 12 to move along bolt 9 to new positions. The arrangement thus provides frequent corrections for wear of small amount (e.g. 0À5 mm.). Fig. 2 (not shown) is a brake resembling the clutch of Fig. 1 but has the armature 4 located in a recess in the core 1. Core 1 is secured to a stationary part, e.g. a motor flange, and rotor 5 is keyed to the shaft to be braked. Fig. 3 shows a spring-applied, electromagnetically-released, brake where the armature 4 lies between the core 1 and pressure ring 10, and the wear-compensating provision is as before. By providing housing 8 with slip-rings the device may be used as a clutch.