a conveying machine for the periodic movement of piece cargo in a straight line, used in assembly plants, foundries, and other industrial enterprises. It simultaneously transports from four to 70 loads with a total weight from 3 to 400 tons and with a step from 0.4 to 6 m. The length of a walking conveyor assembled from identical sections may reach 150 m; the conveying speed is from 1 to 20 m/min, and the duration of one cycle ranges from 0.2 to 10 min. The walking conveyor was introduced in the USSR in the 1960’s. It has since been used in other countries as well because of its simplicity, low cost, and low weight.
A walking conveyor (Figure 1) has a stationary frame with guide rollers, a mobile frame resting on lift wheels, and a drive. Mechanical, pneumatic, or hydraulic devices are used for the drive and lift. In the starting position the mobile frame is lowered, and the loads are set on the stationary frame. At the start of each cycle, the mobile frame lifts the loads above the stationary frame (position I) by means of hydraulic cylinders and moves them forward by one step with the advance of the drive piston (position II). The hydraulic cylinders then lower the mobile frame and place the loads onto the stationary frame with a displacement of one step (position III). In the lowered position, the mobile frame, which is now without loads, returns to the starting position (position IV). The loads are placed and removed at the beginning and end of the conveyor. The conveyor may be automatically controlled. The period between movement cycles is determined by the nature of the production process. The principal disadvantage of walking conveyors is the need to overcome the inertia of the weight of the load and the frame in starting and stopping the drive.
REFERENCESSpivakovskii, A. O., and V. K. D’iachkov. Transportiruiushchie mashiny, 2nd ed. Moscow, 1968.
Veisman, V. F. Shagaiushchie konveiery, 2nd ed. Moscow, 1976.
L. N. KOLOBOV