Improvements in and relating to Metallic Washers for Use with Bolts and Nuts.
Year: 1888

page_text: [Communicated from abroad by DAVID DODD, of Orange, New Jersey, United States
of America, Mechanical Engineer.]
Improvements in and relating to Metallic Washers for Use with
Bolts and Nuts.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co. Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This improvement relates to a lock washer of the type in which a rib is provided
upon the side which is intended for impact against the nut, in order that when the
nut is screwed home the apex of the rib, by embedding itself into the face of the
nut, will displace and force a portion of the metal of the nut convergently against
the bolt. There have been heretofore known two kinds of such washers, one is the
comparatively thin, flat washer, provided with a projecting rib around its inner edge,
shown and described in Letters Patent of the United States No. 258,422, dated
May 23rd, 1882, and the other is the spiral washer provided with a rib around its
concavo edge, shown and described in Letters Patent of the United States No. 340,308,
dated April 20th, 1886. The latter is necessarily made of a comparatively thick bar of
steel, and thus resists compression with such energy that the rib begins its work of
displacing the metal of the nut soon after the nut acquires contact with it, and
continues in the performance of its work during the period while the nut is being
turned the requisite number of revolutions to effect the compression of all the parts
of the spiral washer into the same plane. On the contrary, in the case of the thin,
flat washer, contact is not made with the apex of the rib until the nut has been
screwed nearly home, and the result is that the nut jams upon the washer before
the desired extent of convergent displacement of the metal of the nut has been
effected.
The object of the present invention is to give to the comparatively thin ribbed
washer an increased capacity of effecting the progressive convergent displacement of
the metal of the nut.

page_text: The first part of the invention consists in giving to the thin ribbed washer a
conoidal or dished form, so that when its outer edge is bearing upon the surface of
the object through which the bolt is inserted, the rib around its inner edge will acquire
contact with the face of the nut, and will begin its work of convergently compressing
the metal of the nut toward the bolt at an earlier stage in the operation of screwing
the bolt home, and will continue its work during the period while the nut is being
turned to the extent required to compress the inner portion of the washer into the
same plane as the outer portion.
The second part of the invention consists in notching the rib with which the inner
edge of the washer is provided, and thus forming one or more projections, a portion
or portions of the apex or apices of which are spirally inclined in the opposite
direction from that of the pitch of the bolt and nut screw threads.
When thus constructed, the projections, which for convenience may be called teeth,
perform their displacing function upon the metal of the nut progressively, in a
circular path, and with a less pressure of the washer upon the surface of the object
through which the bolt is inserted. This increases the adaptability of the device for
employment with bolts and nuts used in wooden structures, by diminishing the extent
to which the outer edge of the washer tends to embed itself into the wood during the
performance of the said displacing operation.
The accompanying drawings, showing dished washers embodying the present inven-
tion, and illustrating the use thereof, are as follows :—viz.
Figure 1 is a top view of a dished washer provided around its inner edge with a
continuous outwardly-projecting rib.
Figure 2 is a transverse section taken through the plane indicated by the dotted
line on Figure 1.
Figure 3 is a top view of a dished washer provided around its inner edge with two
lateral projections or teeth.
Figure 4 is a transverse section through the line y, y on Figure 3.
Figure 5 is a sectional view of a bolt, an object through which the bolt is inserted,
a nut applied to the bolt, and a dished washer interposed between the nut and the
object through which the bolt is inserted.
Figure 6 is a sectional view, similar to Figure 3, except that it shows the nut
screwed home, and exhibits in an exaggerated way the displacement of the metal of
the nut caused by the impingement upon its face of the teeth with which the washer
is provided.
Figures 7 and 8 are top views of dished washers provided respectively with three
and four equidistant teeth.
Figure 9 is a top view of a dished washer provided around its inner edge with but
one tooth.
The washer A, is a dished ring of comparatively thin flat steel, provided around its
inner edge either with a continuous outwardly-projecting rib a, as illustrated in
Figures 1 and 2, or with a serrated or notched rib, whereby there are formed one,
two, three or more outwardly-projecting teeth, each of which has a portion a', of its
apex spirally inclined in a direction opposite to that of the pitch of the thread of the
nut B.
In Figure 5 the dished washer is represented as being interposed between the
nut B, and the object C, through which the bolt D is inserted. The face of the
nut adjacent to the object through which the bolt is inserted is represented as
having just acquired contact with the apices, a¹, a², of the two teeth with which
the washer is represented as provided.
In Figure 6 the nut is represented as screwed home, whereby the teeth have been
caused to embed themselves into the face of the nut, and to displace and convergently
compress upon the bolt a portion of the metal of the nut, while the central portion of
the washer has been compressed into the same plane as the outer portion.
The washer A is made of suitable hardened steel, and hence bears with elastic
pressure on one side against the face of the object through which the bolt is inserted,
and on the other side against the nut. Owing to the resistance which the dished

page_text: washer opposes to compression, the teeth begin their work of displacing the metal of
the nut and effecting its convergent motion toward the bolt, when the parts have
acquired the position in which they are represented in Figure 5; and such convergent
movement continues to be progressively effected, in a circular path, while the washer
is gradually yielding to the compression due to the screwing home of the nut,
and until the parts acquire the relative positions in which they are represented in
Figure 6.
It is to be understood that the dishing of the washer may be varied in shape, and
may be either more or less shallow than that represented in the drawings without
departure from the invention, so long as the inner edge of the washer is provided with
the spirally-inclined teeth, as described.
In practice, the dished washers will be given a rather low spring temper, in order
that they may yield to compression without breaking.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent I declare that what I claim is :-
First. The new article of manufacture herein shown and described, the same con-
sisting of a dished metallic washer, provided with a rib, tooth or teeth projecting
outwardly from the inner edge of that one of its sides which is intended for impact
against the face of the nut, substantially as and for the purpose set forth.
Second. The combination, as herein set forth, of a bolt and nut of ordinary con-
struction with a dished metallic washer, provided upon that one of its sides which
bears against the nut with an outwardly-projecting rib, tooth or teeth, whereby during
the screwing home of the nut a portion of the inetal thereof is displaced and forced
convergently toward the axis of the bolt while the central portion of the washer is
being forced toward and against the surface of the object upon which the outer
portion of the washer bears.
13
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.