That a safety nut so simple and so obviously efficient as the one shown
in the annexed engraving should be among the recent inventions in this
line instead of being among the first, is a curious example of the
manner in which inventors often overlook the simplest means of
accomplishing an end. The principle on which this nut operates will be
understood by reference to the engraving. Two nuts are represented on
each bolt, simply for the purpose of showing the difference between the
nut when loose and when screwed down. In practice only one nut is
required to each bolt.
The square nut shown in Fig. 1 is concaved on its under side, so that it
touches its bearings only at the corners and in the outer face of the
nut there are two slots at right angles to each other. When this nut is
screwed home the outer portion is contracted so as to clamp the bolt
tightly.
The hexagonal nut shown in Fig. 2 has but a single transverse slot, and
the nut is made concave on the under surface, so that when the nut is
screwed home it will contract the outer portion and so clamp the bolt.
This nut may be removed and replaced by means of the wrench, but it will
not become accidentally loosened, and the bolt to which it is applied
will always remain tight, as the nut possesses a certain amount of
elasticity. The action of this nut is such as to prevent stripping the
threads of either bolt or nut.
As only one nut is used with each bolt, and as no washer or other extra
appliance is required, it is obvious that a great saving is effected by
this invention.
We are informed that several of the leading railroads have adopted this
nut, and use it on the tracks, engines, cars, and machinery. The Atwood
Safety Nut Company manufacture this article in a variety of forms.
[Illustration: THE ATWOOD SAFETY NUT.]
Further information may be obtained by addressing J. W. Labaree,
Secretary and Treasurer, Room 2, Agawam Bank Building, Springfield,
Mass.
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