Dies for Upsetting Flanges in Rivets.
Year: 1890

page_text: Date of Application, 17th June, 1890-Accepted, 23rd Aug., 1890
COMPLETE SPECIFICATION.
Dies for Upsetting Flanges in Rivets.
I, CHARLES HAZEN BROWN, of the City of Boston, in the County of Suffolk, and
State of Massachusetts, United States of America, Gentleman, do hereby declare
the nature of my invention for DIES FOR UPSETTING FLANGES IN RIVETS, and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:
--
This invention relates to the operation of upsetting rivets which are provided
with solid shanks having cup-pointed outer ends, which are spread or turned outwardly
to form a second head or flange.
The invention has for its object to provide improved means whereby the spreading
or outward turning of the cup-pointed end of the rivet may be effected by successive
operations rapidly performed, and to these ends it consists in a flange-forming die
composed of a plurality of parts, preferably two, one of which comprises the central
portion and the other the marginal or outer portion of the flange-forming die, the
said central portion being supported by a stout spring above the acting face of the
marginal portion, the arrangement being such that when the rivet is pressed against
the central portion the supporting spring of the latter will hold said central portion
with sufficient firmness to enable it to spread the cup-pointed end of the rivet until
the bottom of the recess in the rivet bears upon the acting face of the central portion,
the latter then yielding until it is substantially flush with the marginal portion of the
die, so that the flange which is partially formed by the spreading of the cupped end
of the rivet on the central portion of the die is completed by a pressure against the
marginal portion of the die, the two operations following each other in rapid
succession and without changing the rivet from one die to another.
By thus forming the second flange of the rivet in two stages or operations,
liability of cracking or breaking said flange during the operation is avoided, and a
flange is produced which presents a continuous elge free from cracks or flaws.
Of the accompanying drawings forming a part of this specification,
Figure 1 represents the side elevation of my improved die, in conjunction with
means for supporting it and for pressing the rivet against it.
Figures 2. 3 and 4 represent sections on a larger scale, showing the operation of
the die in forming the second flange of the rivet.
Figure 5 represents a modification showing the die made in three parts.
The same letters of reference indicate the same parts in all of the figures.
In carrying out my invention. referring to Figures 1, 2, 3 and 4, I provide a die
for the formation of the flange or second head on a cup-pointed rivet d of substantially
the form shown in Figure 2, said die being composed of a body i, preferably of
cylindrical form, having at one end a concave acting face a and provided with a
longitudinal bore or socket extending from said face through said bo ly. the face a
being therefore of annular form, and a core or rod j fitted to move lengthwise in said
bore or socket and provided at its outer end with an acting face a of conical, or
approximately conical, form. The core or rod j is supported with its acting face a
above the acting face a, by means of a stout spring which is adapted to yield until
said acting face a¹ is at its marginal portion substantially flush with the inner edge
of the acting face a, as shown in Figure 4. The arrangement of the spring binay be
variously modified, but I do not limit myself to any particular arrangement. I have
here shown the spring supported between its ends by a bearing k attached to the
supporting frame m which holds the body i of the die, one end of said spring being

page_text: engaged with a groove in the lower end of the rod or corej, while the other end
bears upon a screw o which is adjustable in the. frame m and enables the tension of
the spring to be adjusted.
represents a plunger or force which is arranged to press the rivet d against the
core and die body. Said plunger may be reciprocate by any suitable mechanisin ;
but as the plunger and means for operating it form no part of the present invention
the operating mechanism is not shown.
The rivet d being inserted in the pieces of material rr to be united, and placed
between the plunger p and the die ij as shown in Figure 2, the cupped end of the
rivet resting on the elevated face a of the core j, the plunger is pressed downwardly
until the cupped end of the rivet is spread upon the conical face a', as shown in
Figure 3. The spring bis sufficiently stiff to support the coroj and prevent it from
yielding while the cupped end is being thus spread, but when the solid portion of the
shank of the rivet comes to a bearing on the fac a', the continued pressure exerte.i
by the plunger p through the rivet shank causes the corej to vield until the margin
of the face a' is substantially flush with the inner margin of the face a, as shown in
Figure 4, the partially turned flange on the cupped end of the rivet being thus
prossed against the concave face a and therefore spread and converted into a complete
second flange, as shown in Figure 4.
It is important that the yielding movement of the core be limited so that the
margin of the face a¹ will not fall below the inner margin of the face a, as otherwise
the said inner margin would form a shoulder projecting above the face a which
would deface or cut the outer surface of the completed flange formed by the described
operation. I, therefore, provide a stop s at the lower end of the core or rod j,
arranged to arrest the yielding movement of said core when its acting face a' reaches
the position shown in Figure 4. Said stop is preferably an adjustablo screw which
may be set to permit a greater or less displacement, as may be required.
It will be seen that the two operations, although successive, may be performed in
such quick succession that the flange-forming operation will be as rapid as if the
flange were formed entirely by a die or anvil composed of one piece. I have found
in practice that by spreading the cupped end of the rivet by two successive operations,
the liability of cracking the metal of the flange thus formed is entirely obviated, and
a flange is produced having a continuous or unbroken margin.
:
I do not limit myself to making the die in two sections or parts, as in some cases
it may be desirable to make the die in more than two sections. Figure 5 shows three
sections, viz. the rod or core j, the outer portion or body i, and an intermediate
tubular core, the latter being supported by a spring below the acting face of
the core and above the acting face of the body i, and arranged to partially spread
the end of the rivet after the initial spreading by the face a¹ and before the final
spreading by the face a.
Having now particularly described an ascertained the nature of my said inven-
tion, and in what manner the same is to he performed, I declare that what I
claim is:
1. A rivet flange-forming die composed of an enclosing part or body, and one or
more yielding cores or sections located within said body and normally projecting
above the acting face thereof, as set forth.
2. A rivet flange-forming die composed of an enclosing part or body having an
operating face at one end, and a movable core within said body having an operating face
which is normally held with a yielding pressure above the operating face of said body,
as set forth.
3. The combination of the die bo ly having an operating face, a core or plunger
movable in said body and having an operating face surrounded by the operating face
of said body, and a spring whereby the core is normally supported with its operating
face above the operating face of the die body, as set forth.
4. The combination of the die composed of the body i and the spring-supported

page_text: core j, a holder for said parts, and a plunger arranged to force the rivet against said
core and die body, as set forth.
5. The combination of the die composed of the body and the spring-supported
corej, a holder for said paris, a plunger arranged to force the rivet against said
core and die body, and a stop to limit the yielding movement of the core, as set
forth.
CHARLES HAZEN BROWN.