Patent GB-353484-A (GB)
Title: Control mechanism for concrete paving machines
IPC: B28C7/02
Filed: 1930-02-25
Abstract: 353,484. Mixing-machines. WITHERS, J. S., 51, Chancery Lane, London.-(Kochring Co. ; 31st Street, Milwaukee, Wisconsin, U.S.A.) Feb. 25, 1930, No. 6302. [Class 86.] In a concrete mixing machine of the kind described in Specification 308,007, [Class 86, Mixing &c.], which is provided with automatic means for controlling the charging skip and discharge shoot, and with a timing device for controlling the period of mixing, a ingle driving unit is employed to operate the discharge and loading skip, and manually-operated devices are provided whereby the power operation of the discharge and loading devices are rendered non-automatic. The discharge shoot is of the tilting kind and is moved into and out of its discharging position by intermittent half rotations of a shaft 17, Fig. 3, through connections comprising crank-mechanism and a tilting lever. The shaft 17 is rotated through gearing 15, 16, from a shaft 14 which is operated from a constantlydriven shaft 13 through a clutch 12 put into operation by means comprising a lever 8 fitted with rollers 10 engaging a disc 11 co-operating with the clutch. The lever 8 is provided with an arm 8b engaged by a compression spring 9 tending to move the lever clockwise to throw the clutch into gear, which movement is prevented by a spring-influenced detent 7 held, in turn, by a bell crank 5. The latter is actuated in the normal, automatic operation of the machine bv a latch 3 carried on an arm 42 integral with a lever 1 operated from the timing mechanism. By these means, on the completion of a mixing operation, the actuation of the lever 1 releases the detent 7 and permits the arm 8 to throw the clutch 12 into gear thus rotating the shaft 14 which, in turn, drives the shaft 17 to operate the discharge shoot. The shaft 17 is stopped after each half rotation by means of a spring catch 21 which engages notches in a collar on the shaft, the catch being initially released by a rod 24 engaged by the arm 8b. The disc 11, which is loose on the shaft 14, is driven from the shaft 17 by gears 18, 19 and has oppositely-disposed depressions 20 in which the rollers 10 can rest without pressure while the lever 8 is retained by the detent 7. On the release of this lever, the rollers 10 press on the disc 11 and drive the clutch 12. As the disc 11 is rotated, the rollers 10 ride up the sides of the depressions 20 and move the lever 8 backwards till it can be engaged by the detent 7 and retained. The bell crank 5 is operated to effect the return of the discharge shoot to non-discharging position by a second latch 3a carried on a shaft 39, and operated by a linkage from the charging skip, the hoisting gear for which is normally operated by the movement of a push rod 27 actuated by a cam 26 on the side of the gear 16. The automatic control of the discharge shoot can be thrown out of actionby turning a shaft 46, Fig. 7, by means of a handlever 45, the shaft being provided with a cam 47 which displaces the latch 3 so as to render it inoperative ; the discharge shoot can then be thrown into operation by means of a third manuallyoperated latch 3b the latch 3 however preventing this operation till the end of the mixing period by a projection 44 on its lower end lying in the path of the bell crank 5. To prevent the discharge shoot from being operated from the loading skip if the discharge shoot is already in its non-discharging position, the cam 26 on the gear 16 is adapted to engage a bent lever 28 which operates a forked member 29 to move the latch 3a laterally and render it idle. The push rod 27 effects the operation of the loading skip through a manually disconnectable coupling. For this purpose, the rod 27, Fig. 9, operates a rocker 50 freely mounted on a shaft 50a on which is also mounted a rocker 51a to which a hand-lever controlling the skip hoist is directly connected. The rocker 51a carries a spring-influenced pin 53 the operation of which, by means of a hand-actuated cam 54, effects the locking of the two rockers so that they move integrally. The rod 27 operates the rocker 50 through a compression spring 49 permitting lost motion whereby the operator can hold the hand-lever still while the rod 27 is operated, to prevent the actuation of the skip hoist. The pin forming the connection between the rockers can be operated by a pedal bearing on its end.