The Mechanical Handling and Storing of Material

592 THE MECHANICAL HANDLING OE MATERIAL contains thiee compartments for three tubs which run in one cage, the rotation being caused by the weight of the loaded tub a. The -modus operandi then is as follows The loaded tub from the weighing machine is run into the tippler with sufficient velocity to eject the empty tub at the other end by the impact. When at rest the tippler is held in position by two powerful brakes which pass round the two end rings. These brakes are actuated by a lever arrangement under the control of the attendant. On the movement of a lever the brakes are released, and the tippler rotates one- third of a revolution, and is again brought to rest in that position. This brings tub c into the position just vacated by tub a. c is then removed and replaced by a new and full tub as before. The tub a takes up the position shown at b, in which position the side of the tippler stands at an angle of 30°, an oblique plate at the side of the tub forming a temporary hopper into which the coal is discharged, the coal being held in this position until the succeeding tub is tipped, when the tub previously emptied takes the position at c. This is of great importance, as the stop at point b gives the tub time to gently empty itself. This tippler can be made with a cage which will automatically arrest Figs. 836 and 837. Diagrams showing Action of Rigg’s Power-driven Colliery Tippler. itself in three different positions, but it is generally found more convenient to allow it to be manipulated by an attendant. The same airangenient for automatically holding the tubs in position while tipping is used with this appliance, as has been described in the case of the “Fowler” tippler. 1 ha.t is to saj, four claws are made to automatically seizs ths spindles of the tub until it reaches a horizontal position, when they automatically release themselves. These tipplers are made in sizes running from 6 to 10 ft. in diameter. They consist of two mild steel rings built up of channel steel and joined to the esntre boss by channel steel arms of the same section, which arg held together by gusset plates, as shown in the illustration. The encl rings are joined together by side plates of^-in. metal and also by angle irons which form the rails for the tub. The whole apparatus is suspended on a mild steel shaft of 4 in. diameter which revolves in two substantial cast- iron bearings. s Power-driven Colliery Tippler.— I he tip on this system describes a rotary oscillation only, and not a complete revolution, as is generally the case. 1 his power-driven tippler combines all the advantages of the gravity tippler, with the increased speed necessary to enable a large output to be fed on to ths picking belt.