Cripples may project from either side of the ladder, and are usually hung on the rungs. An advantage is gained if, in addition to this, clips are provided to clutch the sides of the ladder.
Buckets and Skips.—Besides the ordinary pail, which needs no description, larger buckets are commonly used for carrying concrete, mortar, earth, or any other moist or friable material.
[Fig. 68] shows the tipping bucket, or skip, which balances on its hinges at A. The hinges are so placed that they are above the centre of gravity of the bucket when empty, and below the centre of gravity when full. This position allows the bucket to remain upright when empty, but it will make half a revolution and empty its contents when full. To prevent this action occurring before it is required, a catch on hinges is fixed on the rim of the bucket at B.
Fig. 68
While the catch is in the position shown, the bucket cannot tilt, but if it is turned back the bucket makes the half revolution required, and after emptying its contents, swings upright of its own accord.
Buckets are constructed of steel, and the standard sizes vary in capacity from 1⁄4 to 1 cubic yard.
For a similar purpose a steel box is used. In this case the bottom of the box is hinged, and on the catch being released, drops out, allowing the material to fall over any desired spot. The catch can be released from above or below by means of a chain connected thereto, and the bottom of the box regains its position when lowered to the ground for refilling.
Each box is fitted with a bow for chain hook, or lugs for chain slings; has a capacity of about 3 cubic feet, is made of steel plates, and may be round or square on plan.
Baskets.—Baskets (as shown in figs. [69]-[73]) have a capacity of about 1 cubic foot.