Fig. 27.
Fig. 28.
Exercise 27: Design for Pillow Block.—Make the necessary working drawings for a pillow block for a shaft 5 inches in diameter, and having a journal 7 inches long.
Brackets.—When a pillow block has to be fixed to a wall or column a bracket such as that shown in figs. 27 and 28 may be used. The pillow block rests between the joggles A A, and is bolted down to the bracket and secured in addition with keys at the ends of the base of the block, in the same manner as is shown, for the attachment of the bracket to the column.
Exercise 28: Pillar Bracket.—Fig. 27 shows a side elevation and part horizontal section, and fig. 28 shows an end elevation of a pillar bracket for carrying a pillow block for a 3-inch shaft. Draw these views properly projected from one another, showing the pillow block, which is to be proportioned by the rules given on page 32. Draw also a plan of the whole. Scale 4 inches to a foot.
Hangers.—When a shaft is suspended from a ceiling it is carried by hangers, one form of which is shown in fig. 29, and which will be readily understood. The cap of the bearing, it will be noticed, is secured by means of a bolt, and also by a square key.
Exercise 29: Shaft Hanger.—Draw the two elevations shown in fig. 29, and also a sectional plan. The section to be taken at a point 5 inches above the centre of the shaft. Scale 6 inches to a foot.
Wall Boxes.—In passing from one part of a building to another a shaft may have to pass through a wall. In that case a neat appearance is given to the opening and a suitable support obtained for a pillow block by building into the wall a wall box, one form of which is shown in fig. 30.