IMPROVEMENTS IN MEANS OR APPARATUS FOR AIDING HUMAN LOCOMOTION IN THE WATER
Year: 1875

page_text: LETTERS PATENT to Robert Henry Wallace Dunlop, of 12, Kent
Gardens, Ealing, in the County of Middlesex, C.B., for the Inven-
tion of "IMPROVEMENTS IN MEANS OR APPARATUS FOR AIDING HUMAN
LOCOMOTION IN THE WATER."
Sealed the 8th December 1875, and dated the 16th September 1875.
PROVISIONAL SPECIFICATION left by the said Robert Henry Wallace
Dunlop at the Office of the Commissioners of Patents, with his
Petition, on the 16th September 1875.
I, ROBERT HENRY WALLACE DUNLOP, of 12, Kent Gardens, Ealing,
in the County of Middlesex, C.B., do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MEANS OR APPARATUS FOR AIDING
HUMAN LOCOMOTION IN THE WATER," to be as follows:-
According to this Invention I attach plates to the hands or feet or
both, all as hereafter described.

page_text: By means of a strap, clastic, or otherwise, I attach to each hand a flat
plate made of wood, vulcanite, metal, or other suitable stiff or only
slightly elastic substance or conformation. I prefer to make such plates
of a shape more or less tapering towards the point or end of the fingers
with a suitable hollow for the wrist, and with the corners rounded and
edges bevelled; I have found that a cordate or heart shape is as suitable
a shape as any.
"
I also make similar plates for the feet and attach them thereto by
straps, as aforesaid, or by means of a laced or other " upper or slipper,
or pocket in such a manner as to leave the heel free and giving_to_the_]
inner edge of said plate a slight upward tilt to enable the swimmer in
the recovery of his stroke to present the plate edgeways to the water.
For this purpose I form the plate with a suitable slight depression for
the ball of the foot to rest in; this formation is with the view of
facilitating or perfecting the "paddle stroke"; but if it be desired 1
merely to "scull" the said depression in the plate and tilting of the
same is unnecessary, and the plate may for that purpose be reversed or
left plain on both sides.
For the paddle stroke I also prefer to give an extra bevel to the
upper edge of the point or toe part, and the lower edge of the opposite 2
part which is towards the heel.
The cordate shape is designed to give balance of pressure around the
ball of the foot which is the centre from which the greatest amount of
power and play of foot action is possible.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of September, in the
year of our Lord One thousand eight hundred and seventy-five, in

page_text: the thirty-ninth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, the said Robert Henry
Wallace Dunlop, Her special licence that I, the said Robert Henry
Wallace Dunlop, my executors, administrators, and assigns, or
such others as I, the said Robert Henry Wallace Dunlop, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MEANS OR APPARATUS FOR AIDING HUMAN LOCOMOTION
IN THE WATER," upon the condition (amongst others) that I, the said
Robert Henry Wallace Dunlop, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Henry Wallace Dunlop,
do hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings, and to the letters of reference marked thereon, that
is to say:-
-
According to this Invention I attach plates to the hands or feet or
both, all as herein-after described.
By means of a strap, elastic, or otherwise, I attach to each hand a
plate made of wood, vulcanite, metal, or other suitable stiff or only
slightly elastic substance or conformation. I prefer to make such plates.
of a shape more or less rounded or tapering towards the point or end of
the fingers with a suitable hollow for the wrist, and with the corners
rounded and edges bevelled I have found that a cordate or heart shape
is as suitable a shape as any.
I also make similar plates for the feet and attach them thereto by
straps, as aforesaid, or by means of a laced or other "upper" or slipper.
or pocket in such a manner as to leave the heel free and giving to the

page_text: inner edge of said plate a slight upward tilt to enable the swimmer in
the recovery of his stroke to present the plate edgeways to the water.
For this purpose I form the plate with a suitable depression for the ball
of the foot to rest in.
I also prefer to give an extra level to the upper edge of the front or
toe part, and the lower edge of the opposite part which is towards the
heel.
The cordate shape is designed to give balance of pressure around the
ball or fore part of the foot which is the part from which the greatest
amount of power and play of foot action is possible.
And in order that this my Invention may be more fully understood,
I will now proceed to describe the same with reference to the accom-
panying Sheet of Drawings which shew some modes of carring my
Invention into effect.
I will here premise that where the hand or foot appliances are so
placed or mounted that the pressure of the hand or the foot is central
I call the appliance a hand or foot plate, but where the pressure of the
hand or foot is to one side of the centre I call the appliance a
hand or foot flipper, the action being somewhat similar to that of the
flipper of a turtle or sea lion.
The Drawings represent in reduced scale two typical forms, viz., the
cordate shape and the "beaver tail" shape, both of which I have found
in practice to be very suitable, but I do not restrict myself to them or
merely to intermediate or similar forms.
I may also here add that having experimented in the subject of :
apparatus and appliances for swimming and diving for some years, I
have so far found that owing to the complexity of human action in
swimming, hinged, webbed, jointed, and umbrella-shaped fins or webs, in
short, all collapsing appliances are unmanageable and comparatively
worthless, and- my-present-Invention does not comprise any such
appliances.

page_text: buckled strap through it, as shewn, and I pass the four fingers and their
knuckles through this strap, and thus obtain perfect command of the
plate, see Figures 6 and 7.
Figure 2 is a plan, and Figure 2" a side view of a beaver tail hand
plate. When the strap shewn in dotted lines is used in this one, that is,
for the right hand, the appliance becomes a "flipper," the pressure being.
out of the centre line.
Figure 3 is a plan, and Figure 3ª a cross section through line A, B,
of a hand flipper of a heart shape and tapering off to one side in
thickness, as is seen in Figure 3*.
Figure 4 is a plan, and Figure 4ª a central section through C, D, of
a cordate hand plate of sheet brass or other suitable material "shelled,"
that is, following in front and rear the convex curve of a thick plate.
Figure 5 is a plan, and Figure 5* a section through E, F, of a large
beaver tail hand plate for racing, or where extra speed is desired slots
may be made at e, e, for a subsidiary strap which also serves for carrying
the plate by when the hand is released.
Figures 6 and 7 shew side view and plan, that is, shewing maximum
and minimum resistance of beaver tail hand plates attached to the
hand.
Figures 8 and 9 are also side view and plan or minimum and
maximum resistance views of foot plates attached to the foot.
Figure 10 is a plan, and Figure 10° a cross section through line G, H,
of a heart shaped foot plate for the right foot fitted with instep strap,
toc pieces, and double porpoise lace for the heel. I prefer this shape for
foot plates. The ventrical on the right or outer wing or side is
preferably larger than that on the left or inner side, as shewn. The
bevels owing to the extra thickness become varied into curves leading
the plate on the lines it should follow in the turnings from "stroke" to
"recovery" and from "recovery" to "stroke," and are suited alike for
breast or back action. The double porpoise lace shewn at the heel gap
(also shewn at Figure 12) is used to prevent the plate from slipping off
the foot. This lace passes round the tendon achilles which is protected
by the tail of an anklet on which are two lace hooks, as shewn in
Figures 8, 9, and 13; this leaves the heel free to move the lace running

page_text: '
that several solutions of nitro-cellulose are even superior to wood for
swimming plates, while metal, gutta percha, and vulcanite, or vulcanized
rubber or canvas rubber stiffened by a core of wood or celluloid, in fact
any stiff or only slightly elastic substance is suitable for the complete
plate or the core of a plate, the harder material with sharp edges being
suited for open water or sea work, and rounded edges with some covering
for crowded swimming baths. For the attachments (anklets, instep
straps, and toe pieces), leather, vegetable leather, or vulcanized or canvas
rubber may suitably be applied.
To ensure that the plate when the toes are pointed shall lie in the
line of the leg or that of the' swimmers progression in diving or gliding
after a stroke and so prevent drag, it may be accommodated to its
position by tilting the inner wing of the plate as already described, or
by deepening the foot bed or heel gap until the correct relativo angle for
the foot and plate is attained.
The circumferential outline of the plates of course admits of endless
modifications. As to size the plates must be made of a size suitable to
the user.
I have for my own use employed a pressure area of from 60
to 121 square inches for a hand plate, and 80 to 140 square inches for a
foot plate.
. In addition to many advantages which will be apparent to persons
making use of the appliances herein-before described, I may mention
that the use of the hand plates or flippers much facilitates the operation
of diving and affords perfect command of direction under water, for
which purposes when the person swimming desires to dive or move
under water it is only necessary for him to point his hand plates or
flippers downwards, and the momentum causes the rest of his body to
follow at once.
It is evident that the above described propellers or appliances may be
used in combination with or as a part of any inflated or floating dress or
buoyant appliance, being especially useful where the amount of buoyancy
is not such as to exceed the diving power which the plates afford.
This Invention is also useful for saving life, a person wearing only an
ordinary life belt, or any inflated dress has comparatively little power of
locomotion even on the surface; whereas with the addition of these

page_text: propellers or appliances he has a considerable power of moving both on
and beneath the surface of the water.
The hand plates are put on and off instantaneously, the foot plates as
casily as a shoe.
•
And having thus fully described and ascertained the nature of this
my Invention, and the manner in which the same is or may be carried
into effect, I declare that I claim, the construction and application of
stiff or but slightly elastic hand and foot swimming plates and flippers,
substantially as herein-before described and as represented in the
Drawings hereunto annexed.
In witness whereof, I, the said Robert Henry Wallace Dunlop,
have hereunto set my hand and seal, this Third day of March,
in the year of our Lord One thousand eight hundred and
seventy-six.