| 摘要 |
1,258,020. Electromagnets. NATIONAL CASH REGISTER CO. 23 Sept., 1970 [6 Oct., 1969], No. 45246/70. Heading H1P. In a high speed printer, (Fig. 1) an impact hammer 28 is mounted on flexure springs 31 against cantilever stops 33 and a hammer penetration stop 44 and is actuated by an arm 17 of flat profile, with an impact face member 22 pivoted at 43 to the yoke 11 of double wound solenoid 13, 91 operating a massive armature 86. A positional backstop 24 and spring 19 control the arm movement and a return spring 29 of the hammer engages the underside of member 22. To reduce inertia and oscillatory stresses tending to fracture arm 17 and to reduce weight to enable high speed operation, the armature 86 is coupled to arm 17 by resilient material 88 (Fig. 2) interposed in a slot of the armature; the arm 17 being interposed between surrounding layers of the material (Fig. 2A not shown) through which operating forces are transmissible by shear. In fabrication, the opposed metal surfaces are roughened, degreased, and coated with a suitable cement after which the material 88 (which may be acrylonitrile butadiene rubber) is moulded to the metal members under heat and pressure, and heat cured. The windings are arranged to apply alternate N and S polarities to the armature to reduce flux in the yoke extension carrying the pivot, and in arm 17; and the reluctance of the flux path through arm 17 to armature 86 is reduced by conferring magnetic properties on the resilient material 88 by introducing particulate Fe 3 O 4 , Fe 2 O 3 , Fe dust or ferrite powder for dispersal by viscous rolling with a wetting agent. The resilient magnetic coupling is stated to be applicable to relays, E/M clutches and brakes, and magnetic transducers. |
