230

CONSTRUCTION OF MACHINES.

[Chap. 11.

that the meal may run easily down, and not cause a dust;fix it so that the meal will spread thinly over its bottomin its descent, and it will cool the better. Cover the topof the spout half-way down, and hang a thin, light cloth,at the end of this cover, to check all the dust that mayrise, by the fall of the meal from the buckets. Remem-ber to take a large cipher off the inside of the board,where it fits to the undermost side of the shaft of the up-per pulley: the meal will otherwise work out along theshaft. Make all tight, as directed, and it will effectuallyprevent waste.

In letting meal into an elevator, it must be let in somedistance above the centre of the pulley, that it may fallclear from the spout that conveys it in; otherwise, it willclog and choke. Fig. 4, Plate VI., is the double socketgudgeon of the lower pulley, to which the conveyer joins.Fig. 3, a b c d, is a top view of the case that the pulleyruns in, which is constructed thus; a b is a strong plank,14 by 3 inches, stepped in the sill, dove-tailed and keyedin the meal-beam, and is called the main bearer. Inthis, at the determined height, are framed the gudgeonbearers a c b d, which are planks 15 by 1^ inches, set 7Jinches apart, the pulley running between, and resting onthem. The end piece c d, 7 inches wide and 2 thick,is set in the direction of the strap-case, and extends 5inches above the top of the pulley; to this the bearersare nailed. On the top of the bearers, above the gud-geons, are set two other planks, 13 by \\ inches, rab-betted into the main bearer, and screwed fast to the endpiece cd: these are 4 inches above the pulley. The bot-tom piece of this case slides in between the bearers, rest-ing on two cleets, so that it can be drawn out to emptythe case, if it should ever, by any means, be overchargedwith meal; this completes the case. In the gudgeonbearer, under the gudgeons, are mortises, made about12 by 2 inches, for the meal to pass from the conveyerinto the elevator; the bottom board of the conveyertrough rests on the bearer in these mortises. The strap-case, joins to the top of the pulley-case, but is not madefast, but the back board of the descending case is stepped