Improved Means or Mechanism for Facilitating the Raising and Retention of Roller Blinds or Shutters and the like.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improved Means or Mechanism for Facilitating the Raising and
Retention of Roller Blinds or Shutters and the like.
A communication by the firm of BAYER & LEIBFRIED, of Esslingen, in the
Empire of Germany, Woodware Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster and 323, High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
This invention has for its object to facilitate the drawing up or raising of Venetian
blinds, roller shutters and the like, by storing up the mechanical power developed
when such are being let down. The end of the drawing up cord is attached to one
end of a powerful spiral spring and when the blind is being let down the spring
is put in a state of tension so that when the blind has to be raised again by
employing the stored up power in the spring the exertion of raising the blind is
diminished. The spiral spring is thus in its greatest state of tension when the blind
is entirely let down or when its full weight is exerted on the drawing up cord.
When the blind is fully rolled up the spring is in a state. of correspondingly
reduced tension. The spiral spring may be so arranged that its tension may be
regulated to correspond with the weight of the blind and it then becomes possible
to approximately poise the blind in any position by the resistance of the corre-
spondingly extended spring without any clamping or fixing device being needed
when the cord is released. By this arrangement the advantage is provided that
roller blinds, Venetian blinds, roller shutters and the like may be as easily drawn up
as let down, as only the frictional resistance is to be overcome, this latter however
will suffice to equalise the small difference between the weight of the shutter and
the tension of the spring and thereby to allow of the automatic fixing of the blind
in any position.
C
Now
On the accompanying drawing, the combination of a roller shutter with a spiral
spring is shown in Figures 1 and 2, whilst Figures 3, 4 and 5 drawn to a larger
scale, show the connection of the drawing up cord with the roller and the spiral
spring. The roller shutter A, is wound on the roller a to which the pulley a' is fixed.
One end of the drawing up cord is attached to this pulley a', whilst the other
end of the same is fixed to the winding up roller b. The latter is made hollow
and the cord is wound round the outside of the hollow roller, whilst inside the
same the spiral spring has one end firmly attached to the spindle b, whilst the
other end of this spring is attached to a pin d which rests in the arm of a frame B.
The spindle b revolves freely on the fixed pivot d and according to the direction
in which it revolves, winds or unwinds the spring attached thereto.
supposing for instance that the roller shutter be drawn up, the spindle 6 may be
adjusted to the pull exercised by the weight of the shutter on the cord when the
shutter is in a certain position, so that the spring wound up to a corresponding
extent, pretty nearly equalises the pull on the cord. If the roll shutter be let down
further the pull on the cord is increased by the greater weight developed, the
spring is however simultaneously placed in a greater state of tension and reaches
its maximum tension when the shutter is completely lowered, that is, when its
entire weight has to be supported by the drawing up cord the essential advantage
of this new arrangement is that the falling down of heavy roller blinds, venetians,
roller shutters and the like is absolutely prevented, and that the drawing up of the

page_text: same requires no particular strength, as merely frictional resistance has to be over-
come and in no case however has the weigbt itself to be lifted as this is effected by
the energy accumulated in the winding up of the spiral spring. Further any par-
ticular fixing device for the drawing up cord is done without and thus the rapid
wearing out of the latter by the same is avoided.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
The improvements in means or mechanism for facilitating the raising and retention
of roller blinds or shutters and the like, consisting in the employment, in such a
means or mechanism, of a spiral spring suitably applied so that the mechanical
force developed in the suspension cord on the letting down of the blind or the like
is transferred to and accumulated in such spring to again, when the blind or the
like is being raised, come into play in a reverse direction so as to assist in the
raising (when frictional resistance only has to be overcome) and retention of
the blind or the like, all substantially as hereinbefore described and shown.
Dated this 18th day of December 1891.
WM. P. THOMPSON & Co.,
Per John Hayes,
Agents for the Applicant.