IMPROVEMENTS IN THE MANUFACTURE OF DOOR SPRINGS, PART OF WHICH SAID IMPROVEMENTS ARE APPLICABLE TO THE MANUFACTURE OF WEIGH- ING MACHINES, STEELYARDS, SCALE BEAMS, AND OTHER ARTICLES OF LIKE NATURE.
Year: 1863

page_text: LETTERS PATENT to George Apdail Thompson, the elder, George Apdail
Thompson, the younger, Upholsterers, and John Latham, Patent Lock
Maker, all of Birmingham, in the County of Warwick, for the Inven-
tion of IMPROVEMENTS IN THE MANUFACTURE OF DOOR SPRINGS, PART OF
WHICH SAID IMPROVEMENTS ARE APPLICABLE TO THE MANUFACTURE OF WEIGH-
ING MACHINES, STEELYARDS, SCALE BEAMS, AND OTHER ARTICLES OF LIKE
NATURE.
PROVISIONAL SPECIFICATION left by the said George Apdail Thompson,
the elder, George Apdail Thompson, the younger, and John Latham, at
the Office of the Commissioners of Patents, with their Petition, on the
30th November 1868.
We, GEORGE APDAIL THOMPSON, the elder, GEORGE APDAIL THOMPSON, the
younger, Upholsterers, and JOHN LATHAM, Patent Lock Maker, all of
Birmingham, in the County of Warwick, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF DOOR SPRINGS, PART
OF WHICH SAID IMPROVEMENTS ARE APPLICABLE TO THE MANUFACTURE OF WEIGHING
MACHINES, STEELYARDS, SCALE BEAMS, AND OTHER ARTICLES OF THE LIKE NATURE,"
to be as follows (that is to say):-
The first part of our Invention relates to certain improvements in the
manufacture of box-arm springs, which have been hitherto so constructed that
the farther a door is opened the greater is the opposition from the spring, so
that its is often found difficult to keep a door fully open, the spring being then
at its strongest point. It is found also that in closing a door the spring

page_text: frequently looses its leverage before the door is quite fastened, the strength of
the spring becoming exhausted before the bolt or latch of the lock takes into
the catch.
Now by our Invention the leverage of the spring is so arranged that upon
the first opening of a door the strength of the spring is at its greatest point,
decreasing according to the distance the door is opened, and the door being.
opened to its fullest extent, the spring retains only sufficient strength to move
or propel the door inwards to that point where more force will be attained by
the spring, and so always to close the door without chance of failure.
In constructing our improved single-action box-arm spring we proceed as
follows: We provide a hollow metal arm or cylindrical case (which is usually
made of brass or iron), and which is to contain the coiled or helical spring.
The arm has a friction roller provided at its extremity, which roller is to work
upon a plate attached to the door. This plate contains a groove, in which the
roller works, the said groove being deepest at the end nearest to the box or
knuckle joint, gradually decreasing in depth outwards until it is finally flush
with the plate. The hollow metal arm is attached to a box, into which is
projected the rod, which at its other end is secured to the spring, the rod
having a double loose joint, on which a friction roller works; a semicircular
plate is secured to the back plate, the said semicircular plate working upon its
axis inside the box. Up this semicircular incline (which now forms a camb
or eccentric) is caused to travel the friction roller of the loose joint, and it will
be evident that as the roller travels up this camb the opposing force will be
greatest at starting, decreasing according to the distance traversed.
The second part of our Invention relates to those kinds of double-action
door springs for swing doors which are employed for the purpose of rendering
them self-closing, and which are let into the floor, and act directly upon the
axis upon which the door turns. It is found that ordinarily such doors are
very liable to be blown open by the wind in consequence of the springs being
so constructed that they are at their weakest point when the doors are closed;
but in springs constructed according to our Invention the spring has the
greatest power when the door is closed, and the least when it is fully open.
We provide a square box, which contains the spring, and to which a rod is
attached, and to which also is secured two loose jointed claws, which work
upon friction rollers provided, the claws being extended by a flat spring.
A square pin protrudes throgh the box, on which pin the door is hung, and
the door being pushed to the right or left acts by means of the square pin
upon one or other of the jointed claws, pressing them inwards. The door
being closed, these claws assume their natural outward positions, thus keeping

page_text: the door on its centre. In this application of our Invention it is the claws
which move, the friction rollers only working upon a pin or axis provided.
In constructing weighing machines, steelyards, scale beams, and other
articles of the like nature, we propose to apply the principle set forth in the
construction of our single-action box-arm springs, but in this case the action
would be reversed, as the semicircular plate or camb would be exactly reversed
in position. The effect of this will be that the leverage or opposing power of
the spring will increase in intensity the farther the spring is moved from its
natural position.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Apdail Thompson, the elder, George Apdail Thompson,
the younger, and John Latham in the Great Seal Patent Office on the
30th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
APDAIL THOMPSON, the elder, GEORGE APDAIL THOMPSON, the younger,
Upholsterers, and JOHN LATHAM, Patent Lock Maker, all of Birmingham, in
the County of Warwick, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of November, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto us, the said George Apdail Thompson, the elder, George Apdail Thomp-
son, the younger, and John Latham, Her special licence that we, the said
George Apdail Thompson, the elder, George Apdail Thompson, the younger,
and John Latham, our executors, administrators, and assigns, or such others
as we, the said George Apdail Thompson, the elder, George Apdail Thompson,
the younger, and John Latham, our 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 "IM-
PROVEMENTS IN THE MANUFACTURE OF DOOR SPRINGS, PART OF WHICH SAID IMPROVE-
MENTS ARE APPLICABLE TO THE MANUFACTURE OF WEIGHING MACHINES, STEELYARDS,
SCALE BEAMS, AND OTHER ARTICLES OF LIKE NATURE," upon the condition (amongst
others) that we, the said George Apdail Thompson, the elder, George Apdail
Thompson, the younger, and John Latham, our executors or administrators,
by an instrument in writing under our, or their, or one of their hands

page_text: 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 we, the said George Apdail Thompson, the elder,
George Apdail Thompson, the younger, and John Latham, do hereby declare
the nature of our said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say):-
The first part of our Invention relates to certain improvements in the
manufacture of box-arm springs, which have been hitherto so constructed that
the farther a door is opened the greater is the opposition from the spring, so
that it is often found difficult to keep a door fully open, the spring being then
at its strongest point. It is found also that in closing a door the spring
frequently loses its leverage before the door is quite fastened, the strength of
the spring becoming exhausted before the bolt or latch of the lock takes into
the catch.
Now by our Invention the leverage of the spring is so arranged that upon
the first opening of a door the strength of the spring is at its greatest point,
decreasing according to the distance the door is opened, and the door being
opened to its fullest extent, the spring retains only sufficient strength to move
or propel the door inwards to that point where more force will be attained by
the spring, and so always to close the door without chance of failure.
In constructing our improved single-action box-arm spring we proceed as
follows: We provide a hollow metal arm or cylindrical case (which is usually
made of brass or iron), and which is to contain the coiled or helical spring.
The arm has a friction roller provided at its extremity, which roller is to work
upon a plate attached to the door. This plate contains a groove, in which the
roller works, the said groove being deepest at the end nearest to the box or
knuckle joint, gradually decreasing in depth outwards, until it is finally flush
with the plate. Or, if preferred, this plate may be dispensed with. The
hollow metal arm is attached to a box, into which is projected the rod, which
at its other end is secured to the spring, the rod having a double loose joint,
on which a friction roller works. A semicircular plate is secured to the back
plate, the said semicircular plate working upon its axis inside the box. Up
this semicircular incline (which now forms a cam or eccentric) is caused to
travel the friction roller of the loose joint, and it will be evident that as the
roller travels up this cam the opposing force will be greatest at starting,
decreasing according to the distance traversed.

page_text: The second part of our Invention relates to those kinds of double-action
door springs for swing doors which are employed for the purpose of rendering
them self-closing, and which are let into the floor, and act directly upon the
axis upon which the door turns. It is found that ordinarily such doors are
very liable to be blown open by the wind, in consequence of the springs being
so constructed that they are at their weakest point when the doors are closed;
but in springs constructed according to our Invention the spring has the
greatest power when the door is closed, and the least when it is fully open.
We provide a rectangular box, into the bottom of which is a pin; upon the
pin works two curved arms or cams, which are kept in an outward position by
means of two pairs of links with friction rollers, acted upon by two rods,
carrying coiled or helical springs, the exact outward position being determined
by two stops fixed to the box. Upon the same pin aforesaid, and above the
curved arms, works a flat plate, having its edge turned down so as to catch
two projecting pins, one upon each of the curved arms or cams aforesaid.
The plate also carries a strong square pin, working through a curved slot in
the top plate of the box, which pin takes into the under side of the door.
When the door is opened in either direction the edge of the moveable plate
carries with it one or other of the curved arms or cams, and thus encounters
the opposing force of one of the coiled springs, the force diminishing as the
door is opened, just in the same way as in the box-arm spring.
That our Invention may be better understood, we have annexed Drawings
thereof, to which we now refer.
Figs. 1 and 2 are a section and plan of the box-arm spring; Figs. 3 and 4,
a section and plan of the double-action spring for swing doors.
In Figs. 1 and 2 A is a hollow metal arm or case containing the spring B,
and carrying at its extremity a friction roller C; D is a box, into which the
metal arm is screwed, and into which also projects the rod E, having the
double loose joint F and friction roller G; the other end of the rod is screwed
to receive an adjustable nut H, by which the strength of the spring can be
varied when the hollow arm A has been removed. The back plate J has a
curved arm K, and works upon the pin L, passing through the box D. The
plate J is attached to the jamb of the door, and as the door is opened the
friction roller G travels up the incline of the arm K, and thus causes the
gradual decrease in the power of the spring.
In Figs. 3 and 4 A is a rectangular box carrying the pin B, upon which
are the curved arms or cams C; D, D, are the pairs of links with friction
rollers E, and rods F, and nuts G, acted upon by springs H; I is the
abutment for the springs; K, K, are the two stops, against which the curved

page_text: arms press when the door is shut; L is a flat plate, with the edge turned
down as at M, and working upon the pin B; N is the square pin to take into
the under side of the door; O, O, are two pins, fixed to the curved arms C,
and one or other of which is acted upon by the edge of the plate L, according
as the door is opened to the right or left. The friction roller E travels up the
curved arm which is being acted upon by the door, and the force of the spring
is thus diminished the farther the door is opened. The curved arm and springs
which are not in action remain bearing against one of the pins O, O.
In constructing weighing machines, steelyards, scale beams, and other articles
of the like nature, we propose to apply the principle set forth in the constrution
of our single-action box-arm springs; but in this case the action would be
reversed, as the semicircular plate or cam would be exactly reversed in
position. The effect of this will be that the leverage or opposing power of the
spring will increase in intensity the farther the spring is moved from its
normal position.
Having now described the nature of our said Invention, and the manner
in which the same is or may be carried into effect, we desire it to be under-
stood that we do not limit ourselves to the precise details herein-before
described, as these may be varied or modified without departing from the
nature of our said Invention; but what we claim, as the Invention to be
protected by the herein-before in part recited Letters Patent, is, substantially
the "Improvements in the Manufacture of Door Springs, Part of which said
Improvements are applicable to the Manufacture of Weighing Machines,
Steelyards, Scale Beams, and other Articles of like Nature," as herein-before
set forth and described, reference being had to the accompanying Drawings.
In witness whereof, we, the said George Apdail Thompson, the elder,
and George Apdail Thompson, the younger, for and on behalf of our-
selves and the said John Latham, have hereunto set our hands and
seals, this Twenty-eighth day of May, in the year of our Lord One
thousand eight hundred and sixty-four.
Witness,
G. R. HOLLAND,
Patent Office;
Birmingham.
G. A. THOMPSON, SEN³. (L.S.)
G. A. THOMPSON, JUN³. (L.S.)