IMPROVEMENTS IN SHEET METAL ELBOWS AND CURVED PIPES, AND IN PROCESSES AND APPARATUS FOR MAKING THE SAME
Year: 1876

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills, of the Firm of Harris
and Mills, of 23, Southampton Buildings, in the County of Middlesex, Patent
Agent, for the Invention of "IMPROVEMENTS IN SHEET METAL ELBOWS AND
CURVED PIPES, AND IN PROCESSES AND APPARATUS FOR MAKING THE SAME."
A communication from abroad by Frederick Hoeltge, Tinsmith and Sheet
Metal Worker, and Augustus Hoeltge, Physician, both of the City of Cincinnati,
in the County of Hamilton, in the State of Ohio, and United States of America.
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph Barnard
Mills at the Office of the Commissioners of Patents on the 7th November 1876.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent. "IMPROVE-
MENTS IN SHEET METAL ELBOWS AND CURVED PIPES, AND IN PROCESSES AND
APPARATUS FOR MAKING THE SAME." A communication from abroad by Frederick
Hoeltge, Tinsmith and Sheet Metal Worker, and Augustus Hoeltge, Physician,
both of the City of Cincinnati, in the County of Hamilton, in the State of Ohio,
and United States of America.
The first part of the Invention consists in constructing an elbow or curved pipe
of sheet metal slightly stretched on its convex side, and with a single joint or seam
on the inner side of the bend. This is effected by the use of a blank having two.
convex sides or edges which are to form the ends of the curved pipe or elbow, and
two concave sides or edges, which after the blank is stamped in suitable dies are
brought together on the inner side of the bend.
The second part of the Invention consists in the construction of sheet metal
blanks for the formation of elbows or curves, said blanks having two opposite
convex sides or edges, and two opposite concave sides or edges.
The third part of the Invention consists in a process for forming elbows or curves
from suitably constructed blanks of sheet metal. In carrying out this part of the
Invention the blank is stamped in successive dies so as to form a deep elliptical
concavity in its central part, and a convexity at each side of the said central
concavity, separated therefrom by straight or nearly straight lines, so that by
bending the sides of the blank forward on these dividing lines until their edges
meet the curved sides will become concentric, or nearly so, with the middle of the
[Price 6d.]

page_text: blank, the latter forming the outer curve of the elbow while the meeting sides form
the inner curve.
The Invention further consists in the construction of a series or succession of dies
for the preliminary forming of elbows or curves, the final die having a central
longitudinal concavity, and two transverse ridges at right angles thereto flanked by
diagonal depressions.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjamin Joseph Barnard Mills in the Great Seal Patent Office on
the 7th May 1877.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent. "IMPROVE-
MENTS IN SHEET METAL ELBOWS AND CURVED PIPES, AND IN PROCESSES AND
APPARATUS FOR MAKING THE SAME." A communication from abroad by Frederick
Hoeltge, Tinsmith and Sheet Metal Worker, and Augustus Hoeltge, Physician, both
of the City of Cincinnati, in the County of Hamilton, in the State of Ohio, and
United States of America.
The Invention relates to improvements in sheet metal elbows and curved pipes,
and in processes and apparatus for making the same, and is fully illustrated in the
accompanying Drawings, in which,―
Figure 1 represents the blank to form the sheet metal elbow; Figure 2, a plan
of the first die B to operate on the said blank; Figure 3, a plan of the die B with
the blank therein; Figure 4, a cross section on the line 4, 4, of Figure 3 of the
die B with the blank therein; Figure 5, a cross section on the line 5, 5, of Figure 3
of the die B with the blank therein.
Figure 6, a plan of the die C for further operating on the blank; Figure 7, a
cross section on the line 7, 7, of Figure 6 of the die C with the blank therein;
Figure 8, a longitudinal section on the line 8, 8, of Figure 6 of the die C and
blank; Figure 9, a view of the blank after it has been stamped in the die C; and
Figure 10, a view of the elbow after the parts a* of tho blank have been turned
over on the lines 2, 2, showing the sheet metal completely formed into a curved
pipe or elbow in readiness for the seam to be closed in any suitable manner.
The first part of the Invention consists in constructing an elbow or curved pipe
of sheet metal slightly stretched on its convex side, and with a single joint or seam
on the inner side of the bend. This is effected by the use of a blank A of the form
shown at Figure 1, having two convex sides or edges a which are to form the ends
of the curved pipe or elbow, and two concave sides or edges a¹, which after the
blank is stamped in suitable dies B, C, are brought together on the inner side of the
bend in the manner shown at Figure 10.
The second part of the Invention consists in the construction of sheet metal
blanks, of the form shown at Figure 1, for the formation of elbows or curves, said
blanks having two opposite convex sides or edges a, and two opposite concave sides
or edges a¹.
The third part of the Invention consists in a process for forming elbows or curves
from suitably constructed blanks of sheet metal. In carrying out this part of the
Invention the blank A is stamped in successive dies B, C, so as to form a deep
elliptical concavity A¹, A³, in its central part, and a convexity at each side of the said
central concavity, separated therefrom by straight or nearly straight lines, so that
by bending the sides of the blank forward on these dividing lines until their edges
meet the curved sides will become concentric, or nearly so, with the middle of the
blank, the latter forming the outer curve of the elbow, while the meeting sides a¹
form the inner curve.
The Invention further consists in the construction of a series or succession of
dies B, C, for the preliminary forming of elbows or curves, the final die C having a

page_text: central longitudinal concavity, and two transverse ridges at right angles thereto,
flanked by diagonal depressions, as shown at Figures 6, 7, 8. By the mode of
operation herein shown and described the corners of the blank A are bent outward
from the male die, while the seam edges a¹, a¹, between the corners are bent in so
as to approach the form of the under or concave side of the finished elbow. This
mode of manipulating the blank facilitates the final folding of the sides, and to
some extent prevents the rupture of the metal.
Having thus described the nature of the said Invention, and the mode in which
the same is carried into effect, I would have it understood that what I claim is,—
First. The process, herein described, of forming sheet metal elbows by stamping
in a suitably formed blank A, a central concavity A2, and two lateral ridges, and
bending the sides forward and toward each other so that the bends a¹, a², therein
will form the inner curve of the elbow, and the central concavity A² will form the
outer curve.
Secondly. The blank A formed with two convex sides a, a, and two concave
sides a¹, a¹, to adapt it to be stamped and bent into the shape of an elbow, as set
forth.
Thirdly. The successive dies B, C, the former having an oblong or elliptic
cavity A, and the other a similar or deeper cavity A², contracted at the sides by
transverse ridges.
Fourthly. The final die C, constructed as shown, with a central longitudinal
cavity A and transverse ridges flanked by diagonal depressions, adapted to stamp
a sheet metal blank A into the required shape to be bent into elbow form in the
manner explained.
In witness whereof, I, the said Benjamin Joseph Barnard Mills, have hereunto
set my hand and seal, this Fifth day of May, in the year of our Lord One
thousand eight hundred and seventy-seven.
B. J. B. MILLS. (L.S.)