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Northrop, E. B.; Chittenden, H. A., Jr. (ed.) / The Wisconsin lumberman, devoted to the lumbering interests of the northwest
(July, 1874)

Yale Lock Manufacturing Company. Progress of the manufacture of locks and of bronze ornamental hardware--description of one of New England's leading manufactures,   pp. 377-386 PDF (3.1 MB)

Page 379

The Wucomsin Lumberman.
trated by the description of a Yale
mortise night latch, an escutcheon of
this kind being applicable to almost any
style of mortise or rim lock; flush locks
-for drawers, desks, etc.-differhig only
in having the body of the lock contain
the mechanism which is here enclosed
in a separate escutcheon.
Sectional views of the escutcheon of
a Yale night latch, showing the princi-
ple of construction embodied in all the
Yale locks:
The escutcheon consists, as will be
seen from an examination of the above
outs, of an exterior shell of cylinderi-
cal form, containing in its lower part a
small cylinder, from which rises a rib of
metal containing the "pin chambers,"
and within which is the " plug," attach-
ed to the inner end of which is the cam
that imparts motion to the bolt. This
plug also contains the key hole.
The escutcheon contains five holes, or
"pin chambers," each formed partly in
the shell and partly in the plug, there-
fore a pin which filled one of these holes
would prevent the rotation of the plug,
but, if the pin were cut in two, the joint
corresponding with that between the
plug and its hole, the plug could revolve
freely, carrying with it one half of the
pin, and leaving the other half in that
part of the pin-ch~mber contained in
the shell. Such is precisely the con-
struction of the lock and its great ele-
ment of security.
Each pin is in two parts-the upper
termed the "driver," the lower the
" pinm"-and above each driver is a light
spring, tending to press drivers and pins
downwards. In this position the drivers
intersect the joint between the shell and
the plug, completely preventing the ro-
tation of the latter. If, by the insertion
of a knife blade, or other instrument in
the key hole, the pins are all raised as
high as they will go, it will be found
that they bar the motion of the plug as
effectually as the drivers did, or if four
of the pins are elevated to their proper
position, the fifth will still prevent the
revolution of the plug.
To open the lock, therefore, all the
pins must be raised simultaneously to
just the proper height, which can be
done only with the right key, since the
variation of one-fiftieth of an inch in
the elevation of either of the pins will
prevent the opening of the lock. This
explains the immense variety of keys
and wide range of permutations of which
the Yale lock is susceptible, surpassing
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