Information
-
Patent Grant
-
6662850
-
Patent Number
6,662,850
-
Date Filed
Tuesday, May 14, 200222 years ago
-
Date Issued
Tuesday, December 16, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 160 171 R
- 160 170 R
- 160 173 R
- 160 8405
- 160 1681 R
-
International Classifications
-
Abstract
A lift cord concealable Venetian blind lift control mechanism is constructed to include a base having two hollow screw rods axially aligned at two sides and selectively mounted in the top or bottom rail of a Venetian blind, a revolving rod inserted through the hollow screw rods, a spring member, which provides a torsional force to the revolving rod, two bobbins respectively threaded onto the screw rods for synchronous rotation with the revolving rod. The left and right lift cords of the Venetian blind each have one end connected to the bottom or top rail and the other end fastened to the bobbin such that when the bottom rail of the Venetian blind lifted or lowered by an external force, the bobbins are synchronously rotated to wind up or let off the lift cords; when the external force disappeared, the bobbins are immovable, keeping the bottom rail in position.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to Venetian blinds and, more specifically, to a lift cord concealable Venetian blind lift control mechanism for use in a Venetian blind for lifting control that keeps the lift cords from sight and from reach of children.
2. Description of the Related Art
A regular Venetian blind is generally comprised of a top rail, a bottom rail, a plurality of slats arranged in parallel between the top rail and the bottom rail, a lift control mechanism for controlling lifting and positioning of the bottom rail to adjust the extending area of the Venetian blind, and a tilting control mechanism for controlling the tiling angle of the slats to regulate the light. The lift control mechanism comprises a lift cord suspended from the top rail at one side for operation by hand to control the elevation of the bottom rail. Because the lift cord is exposed to the outside, it destroys the sense of beauty of the Venetian blind. Further, because a child can easily reach the exposed lift cord, an accident may occur when a child pulling the lift cord for fun.
U.S. Pat. No. 6,024,154 discloses a Venetian blind lift control mechanism, which keeps the lift cords from sight. It is to be noted that the marked numbers described hereunder are quoted directly from U.S. Pat. No. 6,024,154. According to this design, the Venetian blind lift control mechanism comprises a T-shaped retaining member
51
mounted inside the bottom rail
22
on the middle, two lift cord take-up members
32
respectively pivoted to the T-shaped retaining member
51
at two sides and adapted to wind up the lift cords
41
of the Venetian blind, and two spring means
33
adapted to provide a torsional force to the lift cord take-up members
32
respectively. The T-shaped retaining member
51
has a rack
512
, which is forced by springs
513
into engagement with engagement means
322
of the lift cord take-up members
32
to stop the lift cord take-up members
32
from rotary motion, keeping the bottom rail
22
at the desired height. When the user pressed the T-shaped retaining member
51
, the lift cord take-up members
32
are released for free rotation. At this time, the user can lift the bottom rail
22
for enabling the torsional force of the spring means
33
to force the lift cord take-up members
32
to wind up the lift cords
41
, or pull the bottom rail
22
downward against the torsional force of the spring means
33
, so as to adjust the bottom rail
22
to the desired height. This Venetian blind lift control mechanism is complicated, resulting in high manufacturing cost and complicated installation procedure. Further, when adjusting the elevation of the bottom rail, the user has to press the T-shaped retaining member with one hand and move the bottom rail with the other hand.
SUMMARY OF THE INVENTION
The present invention has been accomplished to provide a lift cord concealable Venetian blind lift control mechanism, which eliminates the aforesaid drawbacks. It is the main object of the present invention to provide a lift cord concealable Venetian blind lift control mechanism, which keeps the lift cords of the Venetian blind from sight and out of reach of children. It is another object of the present invention to provide a lift cord concealable Venetian blind lift control mechanism, which is easy to operation. It is still another object of the present invention to provide a lift cord concealable Venetian blind lift control mechanism, which is simple and inexpensive to manufacture. To achieve these objects of the present invention, the lift cord concealable Venetian blind lift control mechanism is installed in a Venetian blind, which comprises a top rail, a bottom rail, a plurality of slats arranged in parallel between the top rail and the bottom rail, and two lift cords vertically inserted through the slats and arranged in parallel. The lift cord concealable Venetian blind lift control mechanism comprises a base installed in one of the top and bottom rails of the Venetian blind, the base comprising two screw rods axially horizontally aligned in a line between the lift cords, an axle hole axially extended through the screw rods; a revolving rod inserted through the axle hole of the base for free rotation relative to the base, the revolving rod having two distal ends respectively extended out of the screw rods; a spring member mounted in the base and adapted to impart a torsional force to the revolving rod; and two bobbins respectively threaded onto the screw rods and coupled to the ends of the revolving rod for synchronous rotation with said revolving rod and for axial movement relative to the screw rods to wind up/let off the lift cords upon forward/backward rotation of the revolving rod.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is an elevational assembly view of a lift cord concealable Venetian blind lift control mechanism according to the preferred embodiment of the present invention.
FIG. 2
is an exploded view of the lift cord concealable Venetian blind lift control mechanism according to the preferred embodiment of the present invention.
FIG. 3
is a sectional view taken along line
3
—
3
of FIG.
1
.
FIG. 4
is similar to
FIG. 3
but showing the bobbins respectively moved from the right side position to the left side position.
FIG. 5
is an applied view of the present invention, showing he lift cord concealable Venetian blind lift control mechanism installed in a Venetian blind.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. from
1
through
3
, a lift cord concealable Venetian blind lift control mechanism
20
is shown comprised of a base
30
, a revolving rod
40
, a spring member
50
, and two bobbins
60
.
The base
30
comprises a casing
31
defining a receiving chamber
32
, two screw rods
33
of same diameter and same thread design respectively horizontally extended from the left and right sides of the casing
31
and aligned in a line, an axle hole
34
of circular cross-section axially extended through the screw rods
33
and the casing
31
, two arm rods
35
respectively horizontally extended from the left and right sides of the casing
31
in parallel to the screw rods
33
at a lower elevation, and two pulleys
36
respectively provided to the free ends of the arm rods
35
. The arm rods
35
have a length approximately equal to the screw rods
33
. The pulleys
36
are disposed in such a direction that the central axis of the pulleys
36
extends perpendicular to the central axis of the arm rods
35
.
The revolving rod
40
is a round rod inserted through the axle hole
34
of the base
30
for free rotation in the axle hole
34
, having two plug portions
41
of non-circular cross-section respectively axially disposed at the ends.
The spring member
50
is, for example, a torsional spring mounted in the receiving chamber
32
of the base
30
, having one end fixedly fastened to the base
30
and the other end fixedly fastened to the revolving rod
40
for imparting a torsional force to the revolving rod
40
in one direction (at the view angle shown in
FIGS. 1 and 2
, the spring member
50
imparts a torsional force to the revolving rod
40
in counter-clockwise direction).
The bobbins
60
are cylindrical members, each comprising a threaded receiving hole
61
axially extended to one end and respectively threaded onto the screw rods
33
respectively, and a plug hole
62
of non-circular cross-section axially extended to the other end in communication with the threaded receiving hole
61
and respectively forced into engagement with the plug portions
41
of the revolving rod
40
. After installation of the bobbins
60
in the revolving rod
40
, the bobbins
60
can be synchronously rotated with the revolving rod
40
. Because the bobbins
60
are respectively threaded onto the screw rods
33
, the bobbins
60
can be rotated forwards/backwards relative to the screw rods
33
. According to the present preferred embodiment, the threads of the screw rods
33
have same pitch, and are extended in same direction. Therefore, the bobbins
60
can be moved in same direction as same speed.
According to the aforesaid arrangement of the screw rods
33
and the bobbins
60
, the left bobbin
60
moves gradually outwards (leftwards) relative to the corresponding screw rod
33
when rotated in counter-clockwise direction, and at the same time the right bobbin
60
moves inwards (leftwards) relative to the corresponding screw rod
33
, i.e. the bobbins
60
are respectively moved from the positions shown in
FIG. 3
to the positions shown in
FIG. 4
during counter-clockwise rotation. On the contrary, the left bobbin
60
moves gradually inwards (rightwards) relative to the corresponding screw rod
33
when rotated in clockwise direction, and at the same time the right bobbin
60
moves outwards (rightwards) relative to the corresponding screw rod
33
, i.e. the bobbins
60
are respectively moved from the positions shown in
FIG. 4
to the positions shown in
FIG. 3
during clockwise rotation.
FIG. 5
shows the lift cord concealable Venetian blind lift control mechanism installed in a Venetian blind
10
. The Venetian blind
10
comprises a top rail
12
fixedly fastened to the top side of the window, a bottom rail
14
disposed at a lower side in parallel to the top rail
12
, a plurality of slats
16
arranged in parallel between the top rail
12
and the bottom rail
14
, and two lift cords
18
vertically inserted through the slats
16
near the left and right sides (the slat tilting control arrangement of the Venetian blind is of the known art and not within the scope of the claims of the present invention, no further detailed description is needed in this regard).
The lift control mechanism
20
is installed in the middle of the top rail
12
, i.e., the base
30
is fixedly fastened to the inside of the top rail
12
on the middle, keeping the screw rods
33
respectively aimed at the left and right sides of the Venetian blind
10
. Further, the lift cords
18
each have a bottom end respectively fixedly fastened to the bottom rail
14
, and a top end inserted into the inside of the top rail
12
and turned toward the center of the top tail
12
and then extended over the bottom side of the corresponding pulley
36
and then turned upwards and fixedly fastened to the left end of the periphery of the corresponding bobbin
60
(i.e., the left-sided lift cord
18
is fixedly fastened to the outer end of the left-sided bobbin
60
; the right-sided lift cord
18
is fixedly fastened to the inner end of the right-sided bobbin
60
), keeping the cord body of each lift cord
18
wound round the periphery of the corresponding bobbin
60
.
When the Venetian blind
10
extended out (i.e., the bottom rail
14
is lowered to the bottom side) as shown in
FIGS. 3 and 5
, the bobbins
60
are respectively disposed at the right side of the respective movable range, and the lift cords
18
each have only a small part respectively wound round the bobbins
60
. When moving the bobbins
60
toward the left side (counter-clockwise rotation under the view angle of FIG.
1
), the bobbins
60
are rotated to wind up the lift cords
18
(see FIGS.
3
and
4
). On the contrary, when moving the bobbins
60
toward the right side (clockwise rotation under the view angle of FIG.
1
), the bobbins
60
are rotated to let off the lift cords
18
.
As stated above, the spring member
50
imparts a torsional force to the revolving rod
40
in counter-clockwise direction, thereby causing the bobbins
60
to be rotated toward the left side (to wind up the lift cords
18
). Because the top ends and bottom ends of the lift cords
18
are respectively fastened to the bobbins
60
and the bottom rail
14
, the gravity weight of the slats
16
and the bottom rail
14
impart a torsional force to the bobbins
60
in clockwise direction, thereby causing the bobbins
60
to be rotated toward the right side (to let off the lift cords
18
). Because the aforesaid two reversed torsional forces are approximately equal (by means of controlling the spring power of the spring member
50
or the weight of the bottom rail
14
, the two reversed torsional forces can easily be balanced) and the bobbins
60
are respectively supported on the screw rods
33
, the stretching force of the lift cords
18
biases the axis of the bobbins
60
slightly away from the axis of the screw rods
33
, thereby causing a friction resistance to be produced between the bobbins
60
and the screw rods
33
to stop the bobbins
60
from free rotation relative to the screw rods
33
, i.e., the current length of the lift cords
18
wound round the bobbins
60
as well as the current vertical distance between the top rail
12
and the bottom rail
14
are maintained unchanged, i.e., the lift cords
18
are capable of lifting the bottom rail
12
to a predetermined height.
If the user holds the bottom rail
14
of the Venetian blind
10
and pulls it downwards, the downward pulling force of the lift cords
18
surpasses the torsional force of the spring member
50
(the difference between the aforesaid two reversed torsional forces surpasses the friction resistance between the bobbins
60
and the screw rods
33
), and therefore the bobbins
60
are synchronously rotated rightwards to release the lift cords
18
at same speed, enabling the bottom rail
14
to be lowered and keeping the bottom rail
14
in horizontal when lowered. If the user releases the hand from the bottom rail
14
, the two reversed torsional forces are returned to the balanced status immediately, thereby causing the bottom rail
14
to be held at the current height. On the contrary, if the user lifts the bottom rail
14
with the hand, the downward pulling force of the lift cords
18
is reduced, and the torsional force of the spring member
50
immediately rotates the bobbins
60
toward the left side, thereby causing the bobbins
60
to wind up the lift cords
18
and to lift the bottom rail
14
until the user has released the hand from the bottom rail
14
.
As indicated above, the present invention provides a lift cord concealable Venetian blind lift control mechanism that stably controls closing, opening, and elevational positioning actions of the Venetian blind, and keeps the lift cords from sight. Because the lift cords are kept from sight, the Venetian blind causes a sense of beauty and, keeps the lift cords from reach of children. The structure of the lift cord concealable Venetian blind lift control mechanism is simple, resulting in low manufacturing cost and convenient installation. When adjusting the extending area (elevation) of the Venetian blind, the user needs only to pull or lift the bottom rail of the Venetian blind with the hand to the desired height.
The lift cord concealable Venetian blind lift control mechanism of the present invention can also be selectively installed in the bottom rail of the Venetian blind. In this case, the top ends of the lift cords are respectively fixedly fastened to the top rail, and the bottom ends of the lift cords are respectively wound round the bobbins.
As another alternate form of the present invention, the screw rods have threads extended in reversed directions, and the bobbins are moved axially in reversed directions when rotated in one direction, i.e., the bobbins are respectively moved toward the base when rotated in one direction, or moved away from the base in reversed directions when rotated in the other direction.
Furthermore, a friction member may be installed in the receiving chamber
32
of the base
30
and disposed in contact with a friction portion of the revolving rod
40
so that a friction force is produced between the revolving rod
40
and the base
30
to stop the revolving rod
40
from rotary motion relative to the base
30
when the bottom rail of the Venetian blind receives no pressure from the user.
Claims
- 1. A lift cord concealable Venetian blind lift control mechanism installed in a Venetian blind, which comprises a top rail, a bottom rail, a plurality of slats arranged in parallel between said top rail and said bottom rail, and two lift cords vertically inserted through said slats and arranged in parallel, the lift cord concealable Venetian blind lift control mechanism comprising:a base installed in one of the top and bottom rails of said Venetian blind, said base comprising two screw rods axially horizontally aligned in a line between said lift cords, an axle hole axially extended through said screw rods; a revolving rod inserted through said axle hole of said base for free rotation relative to said base, said revolving rod having two distal ends respectively extended out of said screw rods; a spring member mounted in said base and adapted to impart a torsional force to said revolving rod; and two bobbins respectively threaded onto said screw rods and coupled to the ends of said revolving rod for synchronous rotation with said revolving rod and for axial movement relative to said screw rods to wind up/let off said lift cords upon forward/backward rotation of said revolving rod.
- 2. The lift cord concealable Venetian blind lift control mechanism as claimed in claim 1, wherein said bobbins each have a plug hole of non-circular cross-section axially disposed at an outer side; said revolving rod is a round rod, having the two distal ends respectively terminating in a respective plug portion of non-circular cross-section respectively engaged into the plug holes of said bobbins.
- 3. The lift cord concealable Venetian blind lift control mechanism as claimed in claim 1, wherein said screw rods have a respective thread extended in same direction for enabling said bobbins to be moved axially in same direction when synchronously rotated with said revolving rod.
- 4. The lift cord concealable Venetian blind lift control mechanism as claimed in claim 1, wherein said base further comprises two arm rods axially aligned at two sides and disposed in parallel to said revolving rod, and two pulleys respectively pivoted to an outer end of each of said arm rods.
- 5. The lift cord concealable Venetian blind lift control mechanism as claimed in claim 1, wherein said base comprises a receiving chamber; said axle hole extends across said receiving hole; said spring member is a torsional spring mounted in said receiving chamber, having one end fixedly fastened to said base and an opposite end fixedly fastened to said revolving rod.
- 6. The lift cord concealable Venetian blind control mechanism as claimed in claim 5, wherein said base further comprises a friction member fixedly provided inside said receiving chamber, and said revolving rod has a peripheral friction portion disposed in contact with said friction member.
Priority Claims (1)
Number |
Date |
Country |
Kind |
91202676 U |
Mar 2002 |
TW |
|
US Referenced Citations (10)