CodalSearch this book — or all of Codal…⌘K
Projects
Sign inStart a book
nydus/How it WorksPublic

Archibald Williams explains the scientific principles behind common mechanisms and physical phenomena such as steam, electricity, light, and hydraulics. The text focuses on the fundamental operation of everyday devices rather than specific models or detailed technical specifications.

Page 393 of 446
Table of Contents

HOW IT WORKS.

an upper notch. The chances therefore were greatly against a wrong key turning the lock.

Fig. 215.
Fig. 215. —The bolt of a Barron lock.

THE CHUBB LOCK

is an amplification of this principle. It usually has several tumblers of the shape shown in Fig. 216. The lock stud in these locks projects from the bolt itself, and the openings, or "gates," through which the stud must pass as the lock moves, are cut in the tumblers. It will be noticed that the forward notch of the tumbler has square serrations in the edges. These engage with similar serrations in the bolt stud and make it impossible to raise the tumbler if the bolt begins to move too soon when a wrong key is inserted.

Fig. 216.
Fig. 216. —Tumbler of Chubb lock.

Fig. 217 is a Chubb key with eight steps. That nearest the head (8) operates a circular revolving curtain, which prevents the introduction of picking tools when a key is inserted and partly

393