GB740322A - Improvements in or relating to hammer mills - Google Patents

Abstract

740,322. Hammer mills. SPROUT WALDRON & CO., Inc. March 17, 1954 [March 24, 1953], No. 7747/54. Class 59. In a hammer mill comprising a housing 10 having rotating hammers 18 and a semi-cylindrical screen 20, the outer wall 36 of the housing is provided with an arcuate opening 40 which is wider than the thickness of the screen so that the latter may be readily inserted and removed without interrupting the operation of the mill, the screen being mounted in a cradle having a flange 25 which forms a closure for the opening 40 when the screen is fully inserted. The screen cradle comprises a pair of main bars 22 having grooves adapted to engage angles 35 mounted within the housing 10, and the flange 25 has a bar 30 welded thereto to serve as a handle. A plurality of separate screens 20a, 20b and 20c of different mesh are supported in angularlyspaced relationship by a rotatable cage 44 on a stand 45. The cage comprises a pair of axiallyspaced spiders 50 each including three radiallyprojecting portions 51 connected in pairs by members 52 provided with side flanges 65 adapted to fit within the grooves in the bars 22. For indexing the cage to bring a screen into alignment with the opening 40 in the housing 10, the spider 50 nearest the stand 45 has mounted thereon a ring 55 which carries three grooved latch plates 57 co-operating with a roller carried by a spring- influenced lever 61 pivoted on the stand 45. This spider also has three radially-projecting flanges 53 provided with slots 54. The screens are releasably locked on the cage by means of spring- pressed plungers mounted on blocks carried by the projections 51, the plungers each engaging a recess in the upper surface of a screen cradle bar 22. A screen is withdrawn from the housing and, after indexing the cage, another screen inserted into the housing by means of a lead screw, 75, Fig. 2, supported by the stand 45 and by a bracket 76 and driven by a reversible drive 77. The inner end of the lead screw carries a hook 80 adapted to engage the handle 30 on the . screen cradle. The lead screw passes through the slot 54 in the lowermost flange 53 on the cage thus locking the cage against rotation until the screen has been withdrawn from the housing.