IMPROVEMENTS IN THE FASTENING OF ARMOUR PLATES
Year: 1883

page_text: LETTERS PATENT to Lewis Wells Broadwell of Rue Herschell, Paris, in the
French Republic, temporarily residing at the Charing Cross Hotel, Strand,
in the County of Middlesex for an Invention of IMPROVEMENTS IN THE
FASTENING OF ARMOUR PLATES
PROVISIONAL SPECIFICATION left by the said Lewis Wells Broadwell at the
Office of the Commissioners of Patents on the 12th February 1883.
LEWIS WELLS BROADWELL of Rue Herschell, Paris, in the French Republic,
temporarily residing at the Charing Cross Hotel, Strand, in the County of
Middlesex, "IMPROVEMENTS IN THE FASTENING OF ARMOUR PLATES'
"
According to my invention to secure an armour plate to vessels forts &c, I form
in that side of the plate that is to be next the backing holes or recesses of a form
increasing in diameter or width as it increases in depth and extending out partly
through the plate. A suitable form of hole resembles a truncated cone with a
short cylindrical extension at the smaller end or mouth. Each fastening bolt is
made with a head at one end and a central hole (the wall of which may be cut or
slit radially) or a recess at the other end.
These bolts are passed from within the vessel or from behind the backing
through it so that the hollow or recessed end of each enters one of the holes or
recesses in the armour plate wherein as the bolt is forced forward its said end is
expanded or opened out by an expanding device of a conical or like shape such as
pyramidal or wedge like. One form of expanding device resembles a frustum of a
cone the smaller end of which gradually merges into a cylindrical extension that
will fit freely within a concentric hole of circular or other cross section extending
some distance into the end of the bolt.
The expanding device extends to the mouth of the hole or recess in the armour
plate; its external form may correspond to the internal configuration of that hole
or recess so that the annular space between the exterior of the expanding device
and the interior surface of the recess may be of equal width in any plane at right
angles to the common axis of the expanding device and hole or recess.

page_text: In some cases however it may be desirable to so form the expanding device that
the width of the said annular space gradually grows less towards the inner end of
the hole or recess in the armour plate. The expanding device may be a separate
piece the smaller end of which can be inserted in the hole in the bolt before the
latter is pushed through the vessel's side or backing and into the hole in the 5
armour plate; or the said device may be formed in one with the armour plate, or
be fixed thereto concentrically within the hole or recess.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lewis Wells Broadwell in the Great Seal Patent Office on the
10th August 1883.
LEWIS WELLS BROADWELL of Rue Herschell, Paris, in the French Republic late
temporarily residing at the Charing Cross Hotel, Strand, in the County-of
Middlesex "IMPROVEMENTS IN THE FASTENING OF ARMOUR PLATES
"
According to my invention to secure an armour plate to a vessel, fort, or the like,
I form in that side of the plate that is to be next the backing, holes or recesses of a
form increasing in diameter or width as it increases in depth and extending out
partly through the plate. A suitable form of hole resembles a truncated cone with
a short cylindrical extension at the smaller end or mouth. Each fastening bolt is
made with a head at one end and a central hole (the wall of which may be cut or
Blit radially) or a recess at the other end.
These bolts are passed from within the vessel or from behind the backing
through it so that the hollow or recessed end of each enters one of the holes or
recesses in the armour plate wherein as the bolt is forced forward its said end is
expanded or opened out by an expanding device of a conical or like shape, such as
pyramidal or wedge like. One form of expanding device resembles a frustum of a
cone the smaller end of which gradually merges into a cylindrical extension that
will fit freely within a concentric hole of circular or other cross section extending
some distance into the end of the bolt.
The expanding device extends to the mouth of the hole or recess in the armour
plate; its external form may correspond to the internal configuration of that hole
or recess. The width of the said annular space gradually grows less towards the
inner or larger end of the hole or recess in the armour plate sufficiently to
compensate for the thinning of the end of the bolt by the process of expansion
when it is being forced into position. The expanding device may be a separate
piece the smaller end of which can be inserted in the hole in the bolt before the
latter is pushed through the vessels side or backing and into the hole in the armour
plate; or the said device may be formed in one with the armour plate or be fixed
thereto concentrically within the hole or recess.

page_text: Fig. 1 of the drawings is a sectional plan of a portion of the side of a vessel
with armour plate secured thereto according to my invention.
a is the armour plate secured to the woodwork or backing b by bolts c c passing
through the inner skin a' through the woodwork or backing b and into the armour
plate. d d are holes or recesses formed in the side of the plate contiguous to the
backing b.
It will be seen these recesses d are as already mentioned constructed of a shape
somewhat similar to the frustum of a cone having the narrowest or mouth end
next to the backing b and extending only a certain distance into the plate a. Each
bolt c is made with a solid head e at one end and has a central hole or recess fat
the other end extending some distance into the bolt. The wall of this hole in the
bolt may be cut or slit radially as indicated in Fig. 2, which is an elevation and
end view of a bolt according to my invention.
Each bolt is passed from within the vessel, through the backing until the
recessed end of the bolt has entered the mouth of one of the holes or recesses d d
in the armour plate and so that (in the case of the arrangement shewn in Fig. 1)
the base of the expanding device bears against the bottom of the hole or recess
in the armour plate.
Then as the bolt is forced forward (by hydraulic pressure or otherwise) its said
end is expanded or opened out by the expanding device g which in the examples
illustrated is of a conical shape, the smaller end of the cone gradually merging into
a cylindrical extension g' reaching to the mouth of the hole or recess d.
It is to be noted that the conical part of the expanding device is of a length
equal to the depth of the conical portion of the hole or recess in the armour plate,
and that the cylindrical extension of the expanding device is such as will enter
freely the hole or recess f in the end of the bolt.
The cylindrical extension of the expanding device may in some cases be
dispensed with, but it is useful as means for attachment of the device to the bolt
as shewn.
In Fig 1 the expanding device is a separate piece as shewn, the smaller end g¹ of
which can be inserted in the hole f of the bolt before the latter is pushed through
the vessel's side or backing b into the hole or recess d in the armour plate a.
this figure one bolt and expanding device is shown about to enter the hole or
recess d and the other bolt is shewn forced forward and fixed therein.
In
Fig. 3 represents a modification wherein the solid head e at the inner end of the
bolt c is dispensed with, and instead of it the bolt is formed with a screw thread
and a nut h is employed whose outer side is flat as shewn. The hydraulic or other
power by which the expanding device is caused to enter the recess d and by which
the hollow end of the bolt c is made to expand is received by the nut h which is
first screwed on to the bolt so that the end of the bolt bears against the inner end of
the recess in the nut.
The head of the nut being flat it is not liable to be deformed by the pressure as
would be the case with the curved solid head e.
Instead of making the conical part of the expanding device g exactly the same
length as the depth of the conical part of the recess d in the armour plate a which
causes the end of the bolt to expand enough to completely fill that recess, it is made
a little shorter so that as shown the bolt e will not completely fill the recess d, the
result is that when the nut h is removed and an ordinary nut e' is applied and the
bolt tightened up, the inner end of the bolt c will leave its contact with the bottom
of the recess d in the armour plate taking the conical expanding device g with it
and thus will leave a space between the end of the bolt and the bottom of the
recess & in the plate as shewn at k. The expanding device in this case may as
shewn be formed without the cylindrical extension.
It is evident that the effect of the blow of a projectile upon the plate will be
absorbed by the backing and will not disturb or affect the bolt.
After a bolt has been forced to its place by a nut h that nut is taken off and
employed for adjusting other bolts in succession, nuts of ordinary construction

page_text: being applied (as above stated) to each bolt after such bolt has been properly
forced in.
Fig. 4 shews a modification in which the expanding device g is formed in one
with the armour plate a and concentric with the mouth of the recess d. In this
case also the expanding device is formed without the cylindrical extension.
In Fig 5 the expanding device g is shewn screwed or otherwise fixed into the
armour plate a concentrically within the hole or recess d.
I would remark that (as indicated above) the forms of the holes or recesses in
the armour plate as also the forms of the expanding devices, may be variously
modified without departure from the essential characteristics of my invention.
Having described the nature of the said invention and explained the manner of
carrying the same into practical effect, what I consider to be novel and original
and therefore claim as the invention secured to me under the herein before in part
recited Letters Patent is; Securing armour plates to ships forts or backings by the
use of recessed bolts in conjunction with expanding devices whereby the ends
of the said bolts are expanded within holes or recesses in the armour plates
substantially as hereinabove described with reference to the drawings.
In Witness whereof I the said Lewis Wells Broadwell have hereunto set my
hand and seal, this ninth day of August in the year of Our Lord one thousand
eight hundred and eighty three