Improvements in and relating to machines for screening or grading stones, sand, gravel, grain, potatoes and such like

摘要

512,698. Sifting apparatus. HENDERSON, G. March 17, 1938, No. 8244. [Class 117] Sifting apparatus comprises two horizontal screens at different levels pivotally connected to a frame by links and vibrated by connecting rods driven from a shaft having a series of eccentrics in such a manner that one screen is raised and moved forward while the other is lowered and moved backwards, the screens also being supported by pairs of upper and lower cushioning springs which are compressed alternately as the screens vibrate. In the form shown, the screens 2, 3 are supported in framework 1 by links 20 and have lugs 15 secured to springs 16, 17 secured to the frame. The screens are vibrated by a shaft 6 through connecting rods 10, the eccentric part of shaft 6 to which one pair of rods 10 is connected being 180 degrees in advance of the eccentric parts to which the rods of the other screen are connected. Rubber sleeves surround the pivot pins of links 20 and the connections of the connecting rods 10 to the screens.