GB926690A - Improvements in or relating to concrete mixers - Google Patents

Abstract

926,690. Concrete mixers. E. WOLFF. July 12, 1961, No. 25273/61. Class 86. [Also in Group XXX] A concrete mixer has a rotating pan 26, Figs. 2 and 3, having a central discharge aperture 27 surrounded by a tubular member 28 which rotates with the pan. Into the annular mixing space thus formed depend from the framework of the machine to the bottom of the pan two stationary mixing members 73, and two baffles 63, 67 pivotable about vertical axes 62, 66, respectively. Depression of the handle 56 discharges the mixer by means of a linkage which simultaneously raises the chamber 28 to put the mixing space into communication with the discharge aperture and pivots the baffles 63, 67 from mixing to discharge positions, as shown, from the baffle 67 by the continuous and chain-dotted line positions of Fig. 2, whereby the mix is directed to the discharge aperture. Cement is fed by an endless band conveyer 99, Fig. 2, from a feed hopper 109 through a flexible tube 97 to a weigh hopper 88; aggregate by a scraper (not shown) attached to cable 121, a guide 127, and an endless band conveyer 113 to a weigh hopper 110; and water through pipes 83, 84. The conveyers 99, 113 are stopped automatically when predetermined quantities of material are present in the hoppers 88, 110 and the water is metered by a flowmeter 86 which controls the shut-off valve 85. There may be more than one conveyer as 113 for different grades of aggregate, operating in succession automatically. The discharge doors 128, 129, Fig. 3, of the aggregate hopper 110 are opened by the manually-operated lever 143, Fig. 2, and the discharge valve 92 of the cement hopper 88 by the lever 147. The cement and water are discharged into the pan on intersecting axes behind the baffle 63 to form a slurry which is covered immediately by material passing through a horizontal slot 64, Fig. 5, in the baffle 63, whereby the slurry is entrained at once in the mix and the presence of cement dust is avoided. The mixing members 73 extend along a chord of the pan and have additional blade parts 74 directed more radially, see Figs. 2 and 4. The angle of the mixing members to the wall of the pan may be adjusted by screws 78, Fig. 2. There may be more than two mixing members. The baffles and mixing members have rubber edge protectors 80, 81, 82, see Figs. 4, 5 and 6. In operation the pan is rotated at 50 r.p.m. and the mix is moved by centrifugal force to the outer wall where it is repeatedly re-directed inwards by the blades 73 and mixed by the blade portions 74. The mixing pan is carried in guides 9 on a frame 1 having transport wheels 2, 2<SP>1</SP>, 3, 31; as shown in Fig. 1, the mixing pan is in the operative position from which it may be lowered, together with the conveyers, into the travelling position by the crank handle 22. The mixer may be towed or self-propelled by an internalcombustion engine, which may also be used to supply power to the mixer and conveyers instead of the electric motors shown.