GB340545A - Automatic concrete mixing machine - Google Patents

Abstract

340,545. Rotary mixers. WITHERS, J. S., 51, Chancery Lane, London.-(Koehring Co. ; 31st Street, Milwaukee, Wisconsin, U.S.A.) July 29, 1929, No. 23313. [Class 86.] In a concrete mixing machine, control devices operate the discharge shoot and include means comprising a latch cam device for locking the charging means during mixing, and for operating them at the end of the mixing period to effect recharging of the drum ; the water supply is also automatically controlled by the operation of the skip, and adjustable means are provided for controlling the timing of the charging and discharging operations. The charging means comprises a loading-skip which is raised by a winch I, Fig. 1, controlled by a lever J. The lever J is fitted with a cam 61 and latch 62, both adapted to be engaged by a catch 60 operated by a rod 59 from the control mechanism. As the skip is raised a rod J<11> is moved thereby to the left, and moves the lever J to the position shown, with the parts 60, 62 in engagement. At the end of the mixing operation the rod 59 is raised and the catch 60 engages the cam 61 to move the lever J to throw the winch into gear, the lever J being carried past its dead centre position in both directions by a spring 1a. There is sufficient free play between the parts 60, 62 to permit partial manual operation of the lever J to throw the brake L off to allow the skip to be lowered. The skip pivots about an axis 2 and is fitted with a crank disc 26<1> having a connection 31 with a disc 29. The latter is mounted on a shaft 27, Fig. 2, which carries a disc 30 fitted with adjustable pins which engage an arm El on a co-axial shaft 28 for controlling the three-way valve E of the water supply ; this valve effects connection of the measuring tank D with the main, and drum, respectively. The disc 29 has two connections 34, 35, the former with a member that starts the timing device G, and the latter with an arm 351 on a control device M. This comprises a pair of concentric shafts 37, 38, Figs. 6 and 7, fitted with arms 47, 48 having spring-influenced pawls 49, 50 engaging notches in the boss of an arm 39 mounted freely on the shafts 37, 38. The arm 39 operates a spring- controlled sliding rod 44 controlling the operation of the discharge shoot, which may be of the kind described in Specification 307,869. The arm 39 is rocked to operate the discharge shoot at the end and beginning of the mixing operation by the actuation of the shafts 37, 38 from the timing device, and skip, respectively. The arms 47, 48 have cam surfaces 52 engaging a broad lever 53 connected by a link 55 with a lever 56 connected in turn to the rod 59 which controls the catch 60. The pawls 49, 50 are thrown out of operation by engaging stops 51 the adjustment of which enables a variable amount of overlap in the charging and discharging operations to ensure that the drum does not rotate idly.