Note: Descriptions are shown in the official language in which they were submitted.
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CONCEALED TYPE VENETIAN BLIND LIFTING CONTROL
MECHANISM
FIELD OF THE INVENTION
The present invention relates to Venetian blinds and, more
specifically, to a concealed type Venetian blind lifting control mechanism,
which keeps the ends of the lift cords of the Venetian blind from sight.
BACKGROUND OF THE INVENTION
A window may be provided with a Venetian blind that can be
opened or closed to regulate the light, air, etc. A regular Venetian blind
comprises headrail, a blind formed of a set of slats and a bottom rail and
suspended from the headrail, a lifting control mechanism adapted for
controlling the lifting of the blind, and a tilt control mechanism adapted
for tilting the slats to regulate the light.
The lifting control mechanism comprises an external lift cord, a
slat lift cord, and a lift lock. The external lift card is suspended from the
headrail of the Venetian blind at one lateral side of the slats for pulling by
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hand. The slat lift cord is inserted through the slats and connected
between the bottom rail of the blind and one end of the external lift cord.
The user can pull the external lift cord to move the slat lift cord, and to
further control the elevation of the blind. Pulling the external lift cord can
simultaneously move the lift lock between the locking position and the
unlocking position. Therefore, the user can adjust the blind to the desired
elevation by means of operating the external lift cord. Because the
external lift cord is suspended from the headrail of the blind at one side of
the slats, it is conveniently accessible. However, because the external lift
cord is not kept out of reach of children, children may pull the external
lift cord for fun. In case the external lift cord is hung on a child's head, a
fetal accident may occur: Furthermore, the external lift cord tends to be
tangled with the tilt cord of the tilt control mechanism or the slats of the
blind.
Taiwan Patent No. 149396 (application no. 8722193) discloses a
Venetian blind lifting control mechanism, which uses a winding spring to
automatically take up the external lift cord after each operation. When
stopped at a particular elevation, the return force of the spring, the weight
of the blind, and the friction force between thf; Lift cord and the related
elements are maintained in balance, keeping the blind positioned in the
desired elevation. However, because the friction force and the spring
force vary with the wear extent of the related elements after a long use of
the Venetian blind, the ends of the slats cannot be maintained in balance
during elevation adjustment of the blind. Taiwan Patent no. 149920
(application no. 87218795) discloses a synchronizing lift cord lifting
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control mechanism, which enables the lift cords to be synchronously
moved. However, this design is complicated, and the complicated parts of
this design must be respectively installed in the headrail and bottom rail
of the Venetian blind.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide a. concealed type
Venetian blind lifting control mechanism, which has a simple structure.
It is another object of the present invention to provide a concealed
type Venetian blind lifting control mechanism, which is easy to install
and safe in use.
It is still another object of the present invention to provide a
concealed type Venetian blind lifting control mechanism; which keeps the
blind in balance during elevation adjustment.
To achieve these objects of the present invention, the concealed
type Venetian blind lifting control mechanism comprises a lift cord roll-
up unit and a lift cord lock. The lift cord roll-up unit has a lift cord roll-
up
assembly and a spring release device, said lift cord roll-up assembly
having a transmission shaft and at least one first stop member fixedly
mounted on said transmission shaft, said transmission shaft having two
ends respectively fastened to the lift cords of the Venetian blind and
adapted for roiling up/letting ofd the lift cords, said spring release device
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being coupled to said transmission shaft to impart a spring release force
to said transmission shaft and to drive said transmission shaft to roll up
the lift cords. The lift cord lock has a second stop member which is
provided with at lease one second stopping portion, said second stop
member being moved between an engagement position where the at least
one stopping portion is respectively forced into engagement with the at
least one first member of said lift cord roll-up assembly to stop said
transmission shaft from rotation, and a release position where the at least
one second stopping portion of said lift cord lock is disengaged from the
at least one stop member of said lift cord roll=up assembly for enabling
said spring release device to rotate said transmission shaft to further roll
up the lift cords.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a preferred embodiment of the
present invention showing the lifting control mechanism installed in a
Venetian blind.
FIG. 2 is an exploded view of the lifting control mechanism
according to the preferred embodiment of the present invention.
FIG. 3 is an assembly view of the lifting control mechanism
according to the preferred embodiment of the present invention.
FIG. 4 is a schematic drawing showing the engagement status of
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the lifting control mechanism according to the preferred embodiment of
the present invention.
FIG. 5 is a schematic drawing showing the release status of the
lifting control mechanism according to the preferred embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. from 1 through 3, a concealed type lifting
control mechanism 10 is installed in a Venetian blind 20 for lifting
control.
The Venetian blind 20 comprises a headrail 21, a blind 22, a lift
cord unit 23, and a tilt rod unit 24. The headrail 21 is adapted for
fastening to the topside of a window, having a mounting portion 21a,21b
at each of the two distal ends thereof. The blind 22 comprises a number
of slats 221 and a bottom rail 222. Each slat 221 has through holes 223
corresponding to each of the mounting portions 21a and 21b of the
headrail 21. The bottom rail 222 comprises a bottom plate 224 and a
cover plate 225. The cover plate 225 cover, the bottom plate 224,
defining with a bottom plate 224 a receiving chamber (not shown).
The lift cord unit 23 comprises two lift cords 23a,23b each having
a first end respectively fixedly connected to the mounting portions
21a,21b of the headrail 2I and a second end respectively inserted in
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proper order through the through holes 223 of the slats 22.
The tilt rod unit 24 couples the blind 22 to the headrail 21 and is
adapted to control the tilting angle of the blind 22, determining the
amount of light passing through the gaps between the slats 221.
Because the Venetian blind 20 is of the known art, no further
detailed description is necessary.
Referring to FIGS. 2 and 3 again, the lifting control mechanism 10
is mounted in the receiving chamber defined by the bottom plate 224 and
cover plate 225 of the bottom rail 222 of the blind 22, comprising lift
cord roll-up unit 11 and a lift cord lock 12. The lift cord roll-up unit 11
comprises a. lift cord roll-up assembly 111 and a spring release device
112. The lift cord roll-up assembly 111 comprises a casing 113, a
transmission shaft 114, two first stop members 115, two lift cord roll-up
members 116, a barrel 117, and a limiter 118. The limiter 118 is fixedly
mounted in the bottom rail 222 of the blind 22, comprising an upright
block 118a disposed at one side, two guide rods 118b perpendicularly
extended from one side of the upright block 118a and arranged in parallel,
and two stop plates 118c perpendicularly extended from the upright block
118a and arranged in parallel between the guide rods 118b. The stop
plates 118c define a receiving space 118d therebetween. The casing 113 is
mounted in the receiving space 118d; having a receiving chamber 113a of
a predetermined profile and a support 113b in the receiving chamber 113a.
The spring release device 112 can be a spring of constant torque, spiral
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spring, or the like. According to the present preferred embodiment, the
spring release device 112 is a spring of constant torque mounted in the
receiving chamber 113a of the casing 113 and fixedly connected with its
one end to the support 113b to provide a predetermined spring release
force. The transmission shaft 114 is inserted through the casing 113. The
barrel 117 is coupled to the transmission shaft 1I4 and mounted in the
receiving chamber 113a of the casing 113 and fixedly connected to the
other end of the spring release device 112. Further, a cover plate 13 is
fastened to the casing 113 to close the receiving; chamber 113a. The first
stop members 115 are ratchet stop members respectively fixedly mounted
on the transmission shaft lI4 at two sides of the casing 113 for
synchronous rotation with the transmission shaft 114. The lift cord roll-up
members 116 are respectively fixedly fastened to the ends of the
transmission shaft 114 for synchronous rotation with the transmission
shaft I I4, each having a spiral wire groove 119 around the periphery for
rolling up the lift cords 23a,23b. The bottom ends of the lift cords
23a,23b are respectively fixedly fastened to the lift cord roll-up members
116. By means of the spring release force of the spring release device 112,
the lift cord roll-up members 116 are rotated with the transmission shaft
114 to roll up the lift cords 23a,23b.
The lift cord lock 12 is mounted in the bottom rail 222 and moved
relative to the limiter 118, comprising a second stop member 121, the
second stop member 121 having an opening 122 greater than the area of
the receiving space 118d and two recessed holes 125 respectively coupled
to the guide rods 118b of the limiter 118, two springs 123 respectively
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mounted in the recessed holes 125 and sleeved onto the guide rods 118b
of the limner 118 to force the second stop member 121 outwards from the
limiter 118, and two second stopping portions 124 disposed on the second
stop member 121 at two sides in the opening 122 corresponding to the
first stop member 115 of the lift cord roll-up assembly 111. After
installation of the lifting control mechanism 10 in the bottom rail 222 of
the blind 22, the second stop member 121 of the lift cord lock 12 is
partially extended to the outside of the cover plate 225 for operation by
hand (see FIG. 1 ).
The operation of the present invention is outlined hereinafter with
reference to FIGS. 4 and 5.
As shown in FIG. 4, when the second stop member 1'21 of the
lifting mechanism 10 receives no pressure (from the user's hand), the
springs 123 force the second stop member 121 outwards to the
engagement position to lock lift cords 23a,23b, and therefore the blind of
the Venetian blind is stopped at the desired elevation, i.e., the second
stopping portions 124 are moved with the second stop member 121
outwards from the limiter 118 by the spring force of the springs 123 to
the circular path of the first stop member 115 to offset the spring release
force of the spring release device112, and therefore the transmission shaft
114 is stopped from rotation, and the blind is stopped at the desired
elevation.
Referring to FIG. 5, when the user pressed the second stop member
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121 against the springs 123, the second stopping portions 124 are moved
with the second stop member 121 away from the ftrst stop members 115
toward the limiter 118 to the release position. ,At this time, the user can
move the bottom rail 222 up and down to adjust the elevation of the blind
22. In other words, the release position is to move the second stopping
portions 124 away from the circular path of the first stop members 115 of
the lift cord roll-up assembly 111, for enabling the spring release device
112 to rotate the barrel 117 and the transmission shaft 141 so that the lift
cord roll-up members 119 can be rotated with the transmission shaft 141
to roll up or let off the lift cords 23a,23b and to further adjust the
elevation of the blind 22.
When adjusting the elevation of the blind 22, the lift cord roll-up
members 116 are synchronously rotated with tlhe transmission shaft 114
to roll up/let off the lift cords 23a,23b. Therefore, the blind 22 is
constantly maintained in balance when lifted or lowered.
As indicated above, the present invention provides a
concealed type Venetian blind lifting control mechanism,
which has a simple structure, and is safe and smooth in use.
Because the lift cords are disposed in the blind and have no
protruding part extended to the outside of the blind, the
invention keeps the lift cords out of reach of children,
preventing occurrence of accident. Because the lift cord roll-up
members are synchronously rotated to roll up/let off the lift
cords, the blind is constantly maintained in balance during
adjustment. Further, the compact design of the concealed type
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Venetian blind lifting control mechanism can easily be
installed in the bottom rail of the blind (alternatively, the
concealed type Venetian blind lifting control mechanism can be
installed in the headrail of the blind)
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