GB351946A - Improvements relating to electromagnetically operated apparatus for imparting vibratory motion to a screen or the like - Google Patents

Abstract

351,946. Sifting-apparatus. REYNOLDS, M. P., 3121, Fairmount Boulevard, Cleveland Heights, Ohio, U.S.A. Dec. 28, 1929, No. 39667. [Class 117.] An electromagnetic vibratory device for operating a screen or like apparatus comprises an electromagnet, an armature which is urged away from the electromagnet by a spring, and a buffer plate in the path of the armature provided with a cushioning spring supported independently of the armature spring. The armature may be attached to a resilient guide strip and spring means may be provided to take up the weight of the screen and its load of material. In the form shown, the electromagnet 12 is contained in a box-like portion 11 of a frame 10 which is mounted on the casing 1 in which the screen 2 is housed, and the armature 13 is attached to the screen by a rod 15. A spring 18 between the underside of the armature and the bottom plate 16 takes the weight of the screen and load. Two extensions 14 of the armature straddle the magnet and are united by a cross-bar 19 on which bears a spring 20. By means of a handoperated screw 22 this spring may be adjusted to hold the armature away from the magnet, when de-energized, for any difference in the load of material on the screen. The armature buffer plates 31 are threaded on pairs of rods 24 between springs 29, 33 and sliding collars 30, 32, adjustable shims 26, 35 being provided for regulating the pressure of the springs. Normally, the armature lies below the level at which the buffer plates are supported by the springs 29, and when the magnet is energized it rises smartly against the buffer plates so as to give to the screen a jar which is cushioned by the springs 33. These springs are so adjusted as to stop the armature just before its striking-plates 3'7 meet the adjustable weaving- plates fixed in the casing when the current reverses, the buffer plates move downwards with the armature until they are arrested by the springs 29. The armature may carry on its lower surface a resilient guide strip 40, the edges of which are seated in recessed blocks 42 of resilient material which are bolted to the casing. The wire screen 2 has reinforced edges 3 which take over brackets or angles 4 adjustable in the frame for tensioning the screen. The bracket 7 for attaching the screen to the armature is mounted on metal plates 5 bolted to the screen.