Patent GB-674921-A (GB)
Title: Improvements in or relating to a silo unloader
IPC: B65G65/38
Filed: 1947-06-18
Abstract: 674,921. Pneumatic conveyers; loading and unloading. LEACH CO. June 18, 1947. [Nov. 26, 1946] No.16079/47. Addition to 636,734. Classes 78 (i) and 78 (iv). [Also in Group I] The silo unloader of the parent Specification is modified by including a vertically movable frame 17 which is provided with (1) a radially disposed rotor arm 30 rotatably connected at its inner end to the centre of the frame, which is centred in the silo, the arm having means for cutting silage loose from the upper surface of the silo and moving it towards the centre of the frame upon rotation of the arm, (2) a rotary agitator 41 for further loosening the silage upon its arrival adjacent the centre of the frame, (3) a pick-up tube 45 at the centre of the frame having a lower open end into which the loosened silage is sucked by a current of air moving upwardly within the tube, (4) a collecting blade 70 on the arm which extends about the agitator and the lower end of the tube to direct the silage to a point below the end of the tube, and, (5) means for rotating the arms and the agitator and for creating an upward current of air in the tube. The rotor arm 30 comprises an inner portion 31 of metal and an outer portion which may be of wood and is provided with curved blades 39 mounted on the arm by means of brackets 40 and arranged so that the outer cutting circle of one overlaps the inner cutting circle of the next outer one. The outermost blade 63 is pivoted by means of its front portion 61 to its bracket 40 and is provided with a roller 64 mounted on a flange 65 adapted to be pressed against the side wall 13 of the silo by means of a spring 66. The collecting blade 70 is set somewhat lower than the other blades, Fig. 4, its purpose being to collect the silage into the path of fingers 44 of the agitator 41 which delivers the silage to the tube 45. All the blades except the collecting blade are provided with plain and serrated cutting edges 74, 75 respectively, either of which may be used by reversing the blade and the front edge in either position has a backward slope 76. The teeth forming the serrated edge 75 have sloping edges and substantially vertical trailing edges. Tube 45 leads upwardly to a fan 46 driven by an electric motor 53 which also drives the rotor arm 30 at about 3 r.p.m. through small sprocket 55, chain 56 and large sprocket 57 attached to the arm 30. Spindle 42 of the agitator 41 is driven in the reverse direction at higher speed by means of a small sprocket 60, a chain 59 passed around it and a large sprocket 58 fixed to frame 17. Slight rotation of frame 17 under the torque produced by the rotor arm is allowed for smooth operation, allowing the blades to rise over sticky patches. A tube 49 is mounted tangentially to the fan 46 so that the silage is thrown upwards by the fan blades 48 along an inverted trough formed by a cut-away portion 50 of tube 49 and a slidable extension 51 the remote end of which, not shown, projects outside the silo wall 13, and is fixed to one of a series of cross bars in a vertical gap in the wall. As the silage is cut, frame 17 sinks but owing to the slidable connection between the tube 49 and extension 51 the position of the remote end of the latter need only be changed at infrequent intervals. As frame 17 descends an electric cable 78 for the motor is pulled out of a can 79 attached to the frame having a funnel top 81.