Improvements in Window Blind Apparatus.
Year: 1892

page_text: Date of Application, 13th Oct., 1892-Accepted, 26th Nov., 1892
COMPLETE SPECIFICATION.
Improvements in Window Blind Apparatus.
We, WILLIAM HOLMES NISBET of 46 Blenheim Gardens Willesden Green
in the County of Middlesex, Engineer, and WILLIAM MCLAREN of 70 Caufield
Gardens West Hampstead in the County of Middlesex, Manufacturer, 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:-
Our invention relates to spring rollers for window blinds in which frictional
contact between two or more surfaces is employed for the purpose of retaining the
blind in any desired position and it consists mainly in making provision for
adjusting the said frictional contact adjusting or regulating the tension or com-
pression of the main or spiral spring within the body of the roller for the purpose
of rotating said roller more efficiently.
In the accompanying drawings which illustrate the invention
Figure 1 is a section of the roller and carrying brackets.
Figures 2 to 7 are details to be hereinafter described.
Figures 8 and 9 are longitudinal and cross sections of a modified form of the
roller and Figure 10 shows a further modification.
In Figure 1 the blind roller or tube 30 which is carried by brackets 1 and 2
to be secured to a carriage window or other window has a hollow cylinder 4
fixed in one end and the said cylinder has one or more grooves 4¹ cut parallel
to its axis as indicated in Figure 7 which is an end view of the cylinder 4. A
hollow disc 5 shown at Figures 1 and 6 formed with projections 5¹ is fitted to
engage the grooves 4'. Within the roller 30 is contained a smaller tube 14
having a short spindle 13 fixed in its one end and which passes through a bearing
cap 3 in the end of the roller, a square or round end being formed on the spindle 13
to engage with the bracket 2 by which the tube 14 and short spindle 13 are
held stationary while the roller is fitted with the bearing cap 3 to enable it to
revolve or rotate upon the spindle 13. In the other end of the tube 14 another
short spindle 12 is inserted the end of which 12' is free to rotate within the
tube 14. This short spindle 12 is carried through the hollow cylinder 4 and
the bracket 1 and has fixed upon its end a cog or ratchet wheel 9 the teeth of
which are engaged by a pawl 15. Encircling the tube 14 is a spiral spring 14¹
one end of which is attached to the cap 3 in the end of the roller the other
end of the spring being attached to the loose short spindle 12 which again is
prevented from rotating by the engagement of the pawl 15 with the cog or ratchet
wheel 9.
Within the hollow cylinder 4 passing through the disc 5 and free to rotate about
the spindle 12 is a loose sleeve or cylinder 6 having ratchet teeth 6¹ formed upon its
end, said ratchet teeth being engaged by a pawl 11 which in turn is secured to
the bracket 1. One end of the sleeve or cylinder 6 is screwed upon its outer
surface and carries two nuts 7 and 8 by means of which any desired amount of
compression may be put upon the spring 7¹ which encircles the sleeve or cylinder 6
and exerts pressure upon a friction washer 31 of fibrous or other suitable material
bearing upon the inner surface of the disc 5, the outer surface of which bears
upon the washer 32 of fibrous or other suitable material. This washer 32 in
turn bears upon the inner surface of the enlarged ratchet end of the sleeve or
cylinder 6.
When the blind is pulled down the roller rotates in the direction of the arrow
upon the spindles 13 and 12.
The spindle 13 being prevented from rotating by the square or keyed round

page_text: end which is fixed in the bracket 2 and the spindle 12 being prevented from
rotating by the cog or ratchet wheel 9 upon its end engaged by the pawl 15,
the spring 14 of which one end is attached to the cap 3 fixed in the end of
the tube or roller 30, the other end being attached to the short spindle 12 is
coiled about the tube 14 and when the weight in the end of the blind is relieved
or raised by the hand of the operator the reaction of the spring 14' causes the
tube or roller 30 to rotate in the reverse direction to that indicated by the arrow
by which means the blind is wound upon the roller 30. The object of the loose
spindle 12 now becomes apparent. Should the tension on the spring 14' be
insufficient to wind the blind fully up, by removing the cap 10 which is screwed
upon the outer face of the bracket 1 a key with prongs to engage the holes 9¹
in the cog or ratchet wheel 9 may be inserted and the spring wound to any
desired degree of tension. When the key is removed the pawl 15 engaging the
cog or ratchet wheel 9 retains the desired tension on the spring. The flange of
the cap 10 when screwed in position coming between the outer or upper surface
of the pawl 15 and the inner surface of the bracket 1 at 15¹ prevents the pawl
becoming disengaged from the cog or ratchet wheel 9 and the spring 14' thereby
losing its tension.
Other means than a key with prongs on it may be adopted for winding the
spring, for example the square upon the end of the spindle 12 may be made to
project so far through the cog or ratchet wheel 9 that a key similar to an ordinary
box spanner or clock key may be put upon it and the spindle 12 turned in the
manner already described.
Figure 5 is a modification in which the cog or ratchet wheel 9 has holes 17 in its
periphery a pawl 16 being so placed as to engage the cog or ratchet wheel from the
under side so that a needle or pricker or other pointed instrument may be inserted
in the holes 17 and the spring wound by pulling the spindle round capstanwise a
portion of the bracket being cut away to facilitate the operation. The pawl may
be placed on the top and the bracket cut away on the bottom side if preferred.
In pulling down the blind as aforesaid the grooves 4¹ in the hollow cylinder 4
engaging the projections 51 on the disc 5 cause it to rotate upon the loose sleeve or
cylinder which in turn is prevented from rotating by the pawl 11 engaging the
ratchet teeth 6' formed upon its large end. Sufficient force has therefore to be
exerted in pulling down the blind to overcome the friction between the washers 31
and 32 and the inner and outer faces of the disc 5.
When the hand of the operator is removed the blind remains in the position to
which it has been drawn the weight in the bottom end of the blind being insufficient
to overcome the aforesaid friction and at the same time sufficient to prevent the
reactive energy of the spring 14' winding the blind up until the weight is relieved
or raised by hand.
Figures 8 and 9 represent a modification showing the same method of winding
the spring 14 adapted to blind rollers in which the frictional contact or brake
device acts upon the inner circumference of the hollow cylinder 20 which corre-
sponds to the hollow cylinder 4 in Figure 1.
Figure 10 is a modification in which instead of a spindle composed of a tube and
one or more parts a plain straight rod or spindle is used. In the arrangement
shown the winding of the spring is effected from the opposite end of the roller to
that in which the frictional brake apparatus is contained.
The brackets 25 and 27 which correspond to 1 and 2 in Figure 1 have round
holes in their centres through which the spindle 24 is passed. The bracket 27 has
a cap screwed into it similar to that at 10 Figures 1 and 4. The spindle 24 after
passing through the bracket 27 has a square formed upon it on which is fixed the
cog or ratchet wheel 27' corresponding to 9 in Figures 1 and 3.
The winding of the spring is performed in the manner described with reference
to Figure 1 and it will be seen that by substituting for the brackets 25 and 27
others similar to 1 and 2 Figure 1 with the exception that the holes through which
the spindle passes must be round in both brackets and by fixing the cog or ratchet

page_text: wheel 271 on the end of the spindle that projects on the outer face of the bracket
substituted for 25 the winding of the spring can be performed from the end of the
roller in which the friction apparatus is contained.
A straight rod or spindle may be substituted for the one shown in Figure 9.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. Window blind apparatus the parts of which are constructed combined and
arranged to operate substantially as described under several modifications with
reference to the annexed drawings.
•
2. In window blind apparatus the provision of means for winding or regulating
the power of the spring in the roller from the outside of either of the carrying
brackets substantially as described.
3. In window blind apparatus the construction of a spring roller having a central
spindle with a part carried through the supporting bracket a ratchet secured on
the end thereof having a pawl engaging it and adapted to retain the spring at any
desired tension applied by winding it substantially as described.
4. In window blind apparatus a roller having a hollow cylinder provided in its
ends in which are cut one or more grooves to engage corresponding projection upon
a disc which is free to rotate or revolve about a sleeve or cylinder one end of which
is screwed to receive one or more nuts the other end being enlarged and having
ratchet teeth cut upon its periphery said sleeve being free to rotate or revolve upon
the central or main spindle substantially as described.
Dated this Twelfth day of October 1892.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.