IMPROVEMENTS IN DYNAMOMETERS, STEAM PRESSURE GAUGES, SPRING BALANCES, OR OTHER SIMILAR TESTING, GAUGING, OR WEIGHING APPARATUS ACTUATED BY MEANS OF A SPRING
Year: 1874

page_text: LETTERS PATENT to Jean Antoine Victor Burg, of Paris, France,
Doctor of Medicine, for the Invention of "IMPROVEMENTS IN
DYNAMOMETERS, STEAM PRESSURE GAUGES, SPRING BALANCES, OR OTHER
SIMILAR TESTING, GAUGING, OR WEIGHING APPARATUS ACTUATED BY MEANS
OF A SPRING."
Sealed the 18th June 1875, and dated the 21st December 1874.
"
.
PROVISIONAL SPECIFICATION left by the said Jean Antoine Victor
Burg at the Office of the Commissioners of Patents, with his
Petition, on the 21st December 1874.
I, JEAN ANTOINE VICTOR BURG, of Paris, France, Doctor of Medicine,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
DYNAMOMETERS, STEAM PRESSURE GAUGES, SPRING BALANCES, OR OTHER SIMILAR
TESTING, GAUGING, OR WEIGHING APPARATUS ACTUATED BY MEANS OF A SPRING,"
to be as follows:-
:-
The Invention relates to improvements in dynamometers, steam
pressure gauges, spring balances, or other similar instruments acting

page_text: the amount of it is shown on a dial plate or index Z by means of a
hand B provided with a pinion C which is driven by a rack O connected
to the arm A' and working in a corresponding slot provided in a guide D
fixed to the opposite arm A. The arms A & A' are respectively
inserted between the cheeks f & f¹ of two curved jaws F & F¹,
whilst props G & G are applied against the inner surface of these
arms, the props and jaws being respectively held together by pins
g & g', on which are respectively fixed the guide D and rack C.
For regulating the working length of the arms A & A³, and con-
sequently the power of the spring, its straight ends a & a¹ are inserted
into corresponding apertures provided in a small cross bar H, in which
apertures also fit tongues 7 & m and 1 & m³, those 1 & 1 forming
the sides of a stay J, which latter and the tongues are fixed together by
the screws ; & j', whilst an adjusting screw I passing through the
stay J serves for pushing the cross bar H forward or backward over the
tongues l, m, and l, m, screws K & K serving for fixing the bar H
in position. If wished another cross bar H² may be applied over the
semicircular part A² of the spring, and by means of a screw Is and nut I³
this part A at pleasure be put into or out of work. The force or power
to be measured is exerted on the handles N & N¹ screwed on the
jaws F&F, or by any other suitable means.
The spring balance represented in Fig. 3 is provided with a helical
spring O inserted in a tube P. Q is a hanger and Q₁a hook, to which
latter the body to be weighed is suspended, and which hook is connected
to the spring O by means of a rod Q³, the upper end q of which forms
a runner or part of a screw, and is inserted between the helixes of the
spring so as to allow of being moved forward or backward in these
helixes and thus put out of work the portion of the spring in contact
with the runner 9 and that situated between this latter and the hook Q'.
A rack R fixed to a boss U fitting on the rod Q² and provided with a set
screw U¹ drives the pinions of the hand S, which latter moves over an
index T for showing the amount of traction exerted on the spring O by
the body suspended at the hook Q¹.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jean Antoine Victor Burg in the Great Seal
Patent Office on the 21st June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JEAN
ANTOINE VICTOR BURG, of Paris, France, Doctor of Medicine, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of December, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Jean Antoine Victor Burg,
Her special licence that I, the said Jean Antoine Victor Burg, my
executors, administrators, and assigns, or such others as I, the said Jean
Antoine Victor Burg, 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 DYNAMOMETERS, STEAM PRESSURE GAUGES,
SPRING BALANCES, OR OTHER SIMILAR TESTING, GAUGING, OR WEIGHING APPARATUS
ACTUATED BY MEANS OF A SPRING," upon the condition (amongst others)
that I, the said Jean Antoine Victor Burg, my executors or adminis-
trators, 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 Jean Antoine Victor Burg, 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 :-
The Invention relates to improvements in dynamometers, steam
pressure gauges, spring balances, or other similar instruments acting by
means of a spring and intended for testing, measuring, or indicating
either muscular or mechanical force, steam pressure, or the weight of

page_text: bodies, and in which the power exerted on the said spring is transmitted
to an index hand or a runner, and thereby indicated on a graduated
limb or scale.
The Invention consists in improved arrangements of the said instru-
ments and especially in the use of an elliptic spring of a particular shapo
and construction, or of other suitable kind of spring, such for instance
as a helical spring provided, as will be explained hereafter, with an
improved quick and easy means for regulating or rectifying the action
of the said springs by suitably lengthening or shortening its working
parts, thereby allowing, lly, of employing in most cases a limb, the
scales or indices of which have been graduated beforehand; and 2ly, of
rectifying the working of the instrument at any moment the same
should fail in giving true indications.
The arrangement of my improved elliptic spring and the mode of
regulating or rectifying its working forming an essential part of the
Invention, I will more particularly describe the arrangement of this
spring and its application to a dynamometer, a spring balance, and a
steam pressure gauge, and finally the arrangement of a spring balance
working by means of a helical spring, and the mode of regulating this
latter; and in order to make this description more easily to be understood
I will refer myself to the here annexed Drawing, in which the Figs. 1
and 2 respectively represent a front and a side view of my improved
dynamometer; Fig. 3, a back view of a spring balance; Fig. 4, a front
view of a steam pressure gauge; these various instruments provided
with my improved elliptic spring; whereas Fig. 5 represents a front
view of a spring balance working by means of a helical spring. In all
these Figures the same letters refer to corresponding parts, and in those
4 & 5, the graduated limb is represented as partly removed in order
better to show the arrangement of the parts situated behind this limb.
In the dynamometer represented in the Figs. 1 & 2 the principal part
is formed by a spring S of an elliptic shape fixed between the cheeks ƒ,f,
&ff, of two handles or braces F & F¹ in such manner that if a
strain either by pressure or by traction be exerted on these handles,
motion will be imparted to a hand or pointer B, and the amount of the
strain, weight, or power exerted be indicated by this latter on a
graduated limb Z movcable on its axis in order to allow of carrying the
hand opposite the zero of the scale. The arrangement and mode of

page_text: working of the spring of the instruments represented in the Figs. 3
& 4 is based on the same principle. The shape of the spring S
resembles partly an ellipsis; the same is formed of a steel blade bend
into two equal elliptic arms A & A' united together by a semicircular
part A, whereas the ends a & a¹ of these arms are made straight and
are fixed on a stay J and pass through corresponding mortice holes
provided in a small cross bar H, which latter may be fixed on these
parts a & a at any required distance from the stay J by means of the
adjusting screws K & K¹, in order either to shorten or to increase the
working length of the arms A, a, & A¹, a¹, impart more or less stiffness
to the spring S, and consequently allow of regulating or rectifying at
once the working of the said spring by causing the same to offer more
or less resistance to the strain exerted on its arms by the medium of
the handles F & F¹ fixed in the middle of the length of the elliptical
parts A & A¹. Two screw nuts I & I', which may be set more or
less far apart on a screw I fixed in the stay J, serve as limiting guides
for the cross bar H. The parts A & A' are respectively held between
the checks f, f, and those f¹, f¹, of the handles F & F¹, whilst
& G fixed on pins g & g¹ passing respectively through the cheeks f,f,
and those ff, are applied against the inner surface of the parts
A'& A'. The handles F & F have at c and c' an angular protruding
part, and opposite thereto two small wedges e & e' are inserted
between the handles and the parts A & A', which wedges may be
caused to advance or receede by means of the set screws E & E¹
working in ears d & d', by which means the said wedges by pressing
on the arms A & A' will in conjunction with the cross bar 1 perfectly
regulate the stiffness or tension of these arms.
props
G
A modification in the arrangement of the handles F & F is
represented in the Figs. 3 & 4; they are much shorter so as to form
small braces, which instead of by the angular projections c & c' and
& wedges e & e¹ are pressed against the arms A & A' by the set
screws & i¹. To the pin of the handles F' is fixed a rack C working
in a corresponding slot provided in a guide D fixed to the pin g of the
handle F, which guide carries the limb Z provided with suitable scales
or indices for indicating the amount of pressure or of traction exerted
on the instrument. m is the arbor of a pinion b driven by the rack C
and carrying the hand B, and if wished also a cursor or dead needle;
the limb Z is moveable on the arbor m so as to allow of setting the zero

page_text: of the indice opposite the hand B. If consequently either a pressure or
a traction be exerted by means of the handles F & F on the arms A
& A' of the spring S, the hand B will be caused thereby to move over
the limb Z and show the amount of the strain on the scale of this limb,
this latter being provided with two concentric indices or scales, viz., one
for indicating the pressure and the other the traction. The pressure is
exerted directly and simultaneously on the two handles F & F',
whereas if traction is to be applied, this is done by preference by pulling
or drawing on two auxiliary handles L & L', to be fixed by means of two
screw tenons M & M on the handles F & F. If wished an auxiliary
limb may be applied in a similar manner, as in gas or water meters, for
indicating fractional divisions.
As the working length of the spring S may be regulated with the
utmost nicety by means of the cross bar H, particularly if performed in
the
conjunction with the wedges e & e¹ or the set screws i & i,
working of the spring S may be regulated in such manner that the pro-
gress of the hand over the limb be in an arithmetical ratio to the strain
or efforts exerted simultaneously on the arms A & A¹, that is to say,
that if the effort is doubled, tripled, quadrupled, or so on, the progress of
the hand will also become doubled, tripled, quadrupled, and so on; this
arrangement allows therefore of making use of limbs with equidistant
graduations or indices, which consequently may be made beforehand by
punching, impressing, or other simple means, thus doing away with the
necessity of graduating them in accordance with the variations of the
spring made use of, and moreover allows of, by suitably altering the
position of the cross bar H, make the same limb appropriate for
registering various kinds of units of weight, such for instanco as pounds,
kilogrammes, or others.
It will be readily understood that any other kind of spring, if pre-
senting the same conditions as the one above described, may be employed,
and that by the application of suitable lever arms the same scale may be
made use of for registering either multiples or fractions of the original
indications.
The spring balance represented in Fig. 3 is constructed on the same
principles as those here above described in respect to the dynamometer
of Figs. 1 & 2, and only presents some differences with this latter in
the arrangement of the parts which serve for transmitting to the spring

page_text: the effort of traction or the amount of weight to be ascertained. A
hook N for suspending the balance is connected to the arm A of the
spring S, whereas the hook N', to which is attached the body, the weight
of which is to be ascertained, is connected to the opposite arm A'. The
mode of regulating the power of the spring is the same as has been
described in respect to the Figs. 1 & 2, with this difference only, that
the cross bar H is caused to advance or receede, and is fixed by means of
a set screw H working in this cross bar and pressing against the
stay J.
Fig. 4 represents my improved elliptic spring S applied to a steam
pressure gauge. This latter consists as usual for such instruments of a
brass box or casing P, provided with a lid and containing the spring S
and graduated limb Z, with the hand or pointer B for registering the
amount of steam pressure. On the brace F of the arm A of the
spring S, is fixed a screw p, on which works an adjusting nut q, turning
freely in a boss r, forming part of the casing P, by means of which nut the
spring S situated behind the limb Z may be caused to rise or to fall for
carrying the pointer B opposite the zero point of this limb Z, which
latter is fixed to the bottom of the casing P by bridges 8, 8. To the
brace F¹ of the arm A¹ of the spring S is fixed another screw p¹, on
which works a nut q', which presses against the conical head of a
piston T, gliding freely in a corresponding tubular shoulder R, fixed to
the lower part of the casing P, the lower end of which piston is flat and
lays on an india-rubber washer or diaphragm y, securely fixed between
the collars & u¹ of the shoulder R and the tube U, by which latter
the gauge is fixed on a steam pipe. Behind the limb Z is fixed the
guide D, in the slot of which glides the rack C, which drives the pinion b
fixed on the axis or pivot of the hand B. His the screw by which the
cross bar H may be caused to advance or receede for regulating the power
of the spring S, and instead of the set screws i & ", knife edges x, x,
and x, x¹, are provided in the mortice holes of the cross bar H, which
edges press against both surfaces of the straight flat parts a and a¹ of the
spring. In the piston T is provided a slot t, in which is inserted a
lever V, which may be either set free or be fixed by means of a set
screw to a rest v¹; this lover on being set free does not interfere with
the working of the piston T, and is only made use of for testing the truc
working of the gauge. For that purpose the lever V having been fixed
by means of the screw to the rest v¹, and a weight o² corresponding

page_text: with a given pressure, say for instance one-half of an atmosphere, having
been applied to the end of the lever V, the hand B, if the instrument
registers true, must receede at once on the limb Z for the distance corre-
sponding with the said pressure of one-half of an atmosphere, but should
the hand fail to do so the working of the spring is to be regulated or
rectified accordingly by means of the screw H¹ till the registering
becomes perfectly true, after which the lever V is set free and the.
weight ² fixed on the top of the screw p or put aside anywhere else. In
the lower part of the slot t is a knife edge.t', fitting into-a corresponding
notch w of the lever V.
•
The spring balance represented in Fig. 5 is provided with a helical
spring O inserted in a tube O¹. Q is a hanger and Q a hook, to which
latter the body to be weighed is suspended, and which hook is connected
to the spring O by means of a rod Q², the upper end Q³ of which is
made into a screw or part of a screw, so as to form a runner inserted
between the helixes of the spring O and allow of being moved upwards
or downwards in these helixes, and thereby put out of work the portion
of the spring in contact with the runner Q³ and that situated underneath.
A rack C, fixed to a boss C¹ fitting on the rod Q and provided with a
set screw C³, drives the pinion of the hand B, which latter moves over
the limb Z for registering the amount of traction exerted on the spring S
by the body suspended to the hook Q. In this arrangement the regu-
lating or rectifying of its working is obtained by causing the rack O
either to rise or to fall for the required distance, so as to carry the hand
opposite the zero of the scale of the limb Z.
Having thus described and particularly ascertained the nature of my
Invention, and the manner of putting the same into effect, I wish it to
be understood that I do not intend to confine myself to the precise
details of the various apparatus here above described, as many variations
may be made therein without deviating from the main principles of the
Invention, but what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
11y. The general arrangement and combination of parts of the here
above described instruments.
21y. The particular shape and arrangement of the elliptic spring S
and the modes described for regulating or rectifying the working of the

page_text: same, and allowing of appropriating the same limb for registering
various units of weight.
3ly. The mode of regulating (or rectifying the working of the helical
spring O of Fig. 5.
4ly. The modes described for carrying the hand B back to the zero
or other suitable point of the limb Z.
In witness whereof, I, the said Jean
hereunto set my hand and seal, this
Antoine Victor Burg, have
Eighteenth day of June, in
the year of our Lord One thousand eight hundred and seventy-
five.
JEAN ANTOINE VICTOR BURG. (L.S.)
Witness,
JOHN DAVID HAYWOOD,
Merchants' Clerk,
18, Boulevard Montmartre,
Paris.