AN APPARATUS FOR STOPPING, AND DETAINING, OR RELEASING AND SETTING FREE CORDS, TAPES. CHAINS. ROPES. OR OTHER FLEXIBLE LINES OR STRINGS
Year: 1852

page_text: LETTERS PATENT to Andrew Edmund Brac, of Leeds, in the
County of York, for the Invention of "AN APPARATUS FOR
STOPPING, AND DETAINING, OR RELEASING AND SETTING FREE CORDS,
TAPES. CHAINS. ROPES. OR OTHER FLEXIBLE LINES OR STRINGS."
COMPLETE SPECIFICATION filed by the said Andrew Edmund
Brae at the Office of the Commissioners of Patents, with
his Petition and Declaration, on the 30th November 1852,
pursuant to the 9th Section of the Patent Law Amendment
Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
ANDREW EDMUND BRAE, of Leeds, in the County of York, send
greeting.
Whereas I am about to petition Her most Excellent Majesty Queen
Victoria, for Herself, Her heirs, and successors, to give and grant
unto me, the said Andrew Edmund Brae, Her special licence that I,
the said Andrew Edmund Brac, my executors, administrators, and
assigns, or such others as I, the said Andrew Edmund Brae, my

page_text: executors, administrators, and assigns, shall at any time agree with,
and no others, from time to time and at all times hereafter during
the term therein expressed, shall and lawfully may inake, use,
exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"STOPPING AND DETAINING, OR RELEASING AND SETTING FREE, CORDS, TAPES,
CHAINS, ROPES, OR OTHER FLEXIBLE LINES OR STRINGS," upon the condition
(amongst others) that I, the said Andrew Edmund Brae, by an
instrument in writing under my hand and scal, shall particularly
describe and ascertain the nature of the said Invention, and in what
manner the same is to be performed, and cause the same to be filed
with my Petition and accompanying Declaration.
NOW KNOW YE, that I, the said Andrew Edmund Brac, do here-
by 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 (that is to say):
My Invention consists of an apparatus through which cords, tapes,
chains, ropes, or other flexible lines or strings, are free to pass in
one direction, but in the contrary direction are held fast and
retained until set at liberty by an easily produced counteraction.
I declare my said Invention to be applicable to any purpose wherein
facility in the detention or release of cords, tapes, chains, ropes, or
other strings is desirable; but the more immediate purpose to which
I apply it is to the detention and release of the cords or other
strings whereby Venetian or other blinds, curtains, maps, pictures,
or articles of a similar nature, are raised rolled, or gathered up, to
the end that the same may be more readily arrested and maintained
at any desired altitude. I declare my said apparatus to consist of
two equal and similar segments of excentric sheaves or rollers, tho
circumferential surfaces or edges of which are of sufficient breadth
to receive between them the cords or other strings intended to be
acted upon. These excentric segments, the broad circumferential
edges of which may be either plane or corrugated, or covered with
some substance or fabric to increase their frictional or holding
power, are free to revolve upon pivots fixed in appropriate cheeks

page_text: or back plates, and so adjusted that their circumferential edges arc
opposed to each other at such distance that when their longer radii
coincide (or form one straight line), the said circumferential edges
are in contact, or nearly so, but when the shorter radii of the said
excentric segments coincide (or form one straight line), an opening
subsists between their circumferential edges more than sufficient
to admit of the free passage between them of the cords or other
strings for which the apparatus may be designed. Intermediate
between these two extreme positions some situation of the segments
must necessarily occur wherein any interposed cord or string of
suitable size shall be jammed or held fast; now, if the pull or strain
upon such cord or string be in a direction to favour the mutual
approach of the longer radii of the segments, the holding and
jamming power of the said segments will be thereby increased; but
if, on the contrary, the pull or strain be in the opposite direction,
so as to favour the approach of the shorter radii, the effect will be
that the segments will open, the interstice between their circum-
ferential edges will be widened, and the interposed cords or other
strings set free. But, inasmuch as it is sometimes necessary to set
free the interposed cords or strings, while the strain upon them
continues in the first named direction, I affix to one or both of the
before described excentric segments a counteracting or releasing
back pull or action, independant of, and separate from, the interposed
cords or strings; the effect of which back pull, when acted is
to open the segments by causing their shorter radii to approach,
and consequently to set free the cord or cords, or other strings,
which they held in detention. I further declare, that it is necessary
to the due action of the apparatus, that the said excentric segments
should move or revolve with mutual, corresponding, and simul-
taneous action; such that similar radii in each segment may always
be opposed. To secure such mutual action, I connect the two
segments together, either by sliding parallel bars, or by affixing to
cach segment cogged teeth truly centered, so that the teeth of onc
segment shall work between and within those of the other segment,
thereby constraining the said segments to mutual, similar, and
upon,

page_text: simultaneous motion and action. I further declare, that it is
desirable to give to the said segments a constant tendency to
maintain that position wherein the interstice between them is least;
for this purpose, I apply to one or both segments one or more
springs or weights, by the pressure of which the said segments are
impelled to that position in which their longer radii coincide; by
this means they are always maintained in close contact with what-
ever cord or cords, or other strings, may be interposed between
them, so as to be ready at any time to close upon and retain the
said cords or strings. Now, in order to apply my said Invention
to the particular purposes herein-before declared, that is to say, to
the detention and release of the cords or others strings whereby
Venetian or other blinds, curtains, maps, pictures, or articles of a
similar nature are raised, rolled, or gathered up, to the end that the
same may be more readily arrested and maintained at any desired
altitude, I place the said excentric segments within a box or casing
of brass, or other suitable material, with springs and releasing back
pulls arranged as already described. I fasten the said box or
casing in any convenient situation, as for example, inserted into the
substance, or affixed upon the surface, of the top rail, from which the
blind or other object depends. I then convey the cords or strings
by which such objects are raised, rolled, or gathered up, over
suitable leading pullies, to and through the interstice between the
curved excentric surfaces of the said segments, the situation of the
segments being so arranged, with regard to their longer and shorter
radii, that the pull or strain upon the cords or other strings used for
raising or gathering up the said blinds, or other objects, shall be in
the direction favourable to the opening or widening of the said
interstice; while, on the other hand, the reaction caused by the
weight of the said blinds, or other objects, shall be in the contrary
direction, that is, in the direction favourable to the closing or
narrowing of the said interstice; therefore, so soon as the power
by which the blind, or other object, is raised ceases to act, the
segments immediately close upon and retain the supporting cords
or strings, and thereby prevent their regress, until set free by the

page_text: counteracting back pull before described. Lastly, I declare that,
although I use and greatly prefer pairs of segments moving simul-
taneously, yet I do not confine myself to them; but I claim as my
Invention the narrowing or widening of interstices by the revolution
of curved excentric surfaces, whether the same be opposed to and
act against similar curved revolving excentric surfaces, or against
abutments or supports of any other shape or description, for the
purpose of holding or retaining within the said interstices, or of
releasing and permitting the passage through and from the same, of
cords, tapes, chains, ropes, or other flexible lines or strings.
In witness whereof, I, the said Andrew Edmund Brac, have
heretofore set my hand and seal, this Twenty-sixth day of
November 1852.
ANDREW EDMP. BRAE. (L.S.)
Signed and scaled by the said Andrew
Edmund Brae, in the presence of
J. B. CHANTRELL.