GB2060743A

GB2060743A - A control mechanism for vertical slat blinds

Info

Publication number: GB2060743A
Application number: GB7935331A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-10-11
Filing date: 1979-10-11
Publication date: 1981-05-07
Also published as: GB2060743B

Abstract

A control mechanism (9) for a vertical slat blind includes a handle (11) which is dependant from a sliding-head (10) and drivingly connected to an operating shaft (3) by a Bowden cable (14) and spur gears (15, 16) mounted on the sliding-head (10). The drive connection transmits rotation from the handle (11) to the shaft (3) which, through respective worm gears (7, 8) carried by wagons (4) slidable on the shaft, alters the pitch of blind slats (6) suspended from the wagons (4). The blind is drawn and-opened by using the handle (11) to slide the sliding head (10) and wagons (4) along the shaft (3), the sliding-head and wagons being interconnected by couplings (17) which ensure the wagons (4) are drawn in succession to regularly spaced-apart positions. <IMAGE>

Description

SPECIFICATION Control mechanism for vertical slat blinds The present invention relates to control mechanism for vertical blinds.

More particularly, the invention is concerned with a control mechanism for a vertical slat blind of the type including: an an elongate head-rail; --- an operating shaft extending parallel to the head-rail and supported by the latter for rotation by the control mechanism; a a plurality of wagons each captive on and slidable along the operating shaft, and carrying a respective blind slat suspender for rotation about a substantially vertical axis, the wagons being guided by the head-rail when the blind is being opened or drawn;; drive transmission means carried by each wagon for transmitting rotation from the shaft to the slat suspender, and - couplings which interconnect adjacent wagons, the couplings being extendable by a predetermined amount in one direction of wagon sliding so as to ensure that the wagons are pulled to regularly spaced-apart positions along the shaft when the blind is drawn.

The control mechanism of a typical vertical slat blind of the aforesaid type is mounted at one end of the head-rail, effecting rotation of the operating shaft directly through a chain-operated pulley, and sliding of the wagons by means of an endless cord which passes around pulleys at each end of the head-rail. The cord runs through each wagon and is anchored within the leading wagon so that, when the cord is pulled in the blind drawing direction, the leading wagon is pulled directly whilst the trailing wagons are pulled successively by the couplings.

Such a construction is quite satisfactory for blinds which are factory made to specific lengths, but is not particularly suited to the "do-it-yourself" market where there is a demand for a blind which can easily be shortened to meet a user's own requirements and which is cheaper than a "tailormade" blind.

The object of the present invention is to provide a simplified control mechanism for a vertical slat blind of the aforesaid type which renders the blind suitable for the "do-it-yourself" market and is cheaper to produce than known blinds of this type.

According to the present invention there is provided a control mechanism for a vertical slat blind of the above specified type, in which the control mechanism is carried by a sliding-head which is coupled to the leading wagon, so as to lead the wagons when the blind is being drawn, and has a dependant handle by which a user effects sliding of the wagons, the handle being drivingly connected to the operating shaft to effect rotation of the latter.

The transmission means may comprise any suitable form of gearing such as, for example, bevel gears or crossed-axis helical gears, and the operating shaft may have any cross-sectional profile for example, a square section which is suitable for drive engagement with one gear wheel of the transmission. In a preferred embodiment the shaft is splined and these splines may comprise one member of the transmission means. In the preferred embodiment, however, the transmission means comprise worm gears, the worm wheels being splined onto the operating shaft and the worms being carried by the slat suspenders.

The sliding-head may be formed by a modified wagon and may be provided with a slatsuspender, but in a preferred embodiment the sliding-head is not provided with a slat suspender and is closely connected with the adjacent, leading, wagon.

The driving connection between the handle and the operating shaft may comprise bevel gearing, with respective wheels at adjacent ends of the handle and shaft, or a direct connection through a Bowden cable. In the preferred embodiment, in order to obtain the required torque, the handle is attached to a Bowden cable which is drivingly connected to the shaft through spur gears. These spur gears may have externally meshing wheels or, when space is limited, internally meshing wheels, the shaft having the externally-toothed wheel.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a vertical slat blind including a control mechanism according to the present invention, and Figure 2 is view similar to Figure 1 showing the control mechanism on an enlarged scale.

Referring now to the drawings, there is shown a vertical slat blind having an elongate, channelsection head-rail 1 which is closed at each end by a respective bearing block 2 moulded from a plastics such as, for example, nylon. The bearing blocks rotably support a splined operating shaft 3 which extends parallel to, and within, the head-rail 1. A number of wagons 4, only one of which is shown, are captive upon and slidable along the operating shaft 3, being guided during sliding by the head-rail 1. Each wagon 4 has respective drive transmission means which transmit the rotation of the operating shaft 3 through 900 about a substantially vertical axis, such that rotation of the operating shaft 3 changes the pitch of a blind slat 6 carried by the suspender 5.The transmission means comprise a worm 7, which is carried by the slat suspender 5, and a meshing worm wheel 8 which has internal splines 8A for drive engagement with the operating shaft 3.

The rotation of the operating shaft 3 and the sliding of the wagons 4 is effected by a manuallyoperated control mechanism, generally indicated 9. The control mechanism 9 is carried by a slidinghead 10 which is captive on the operating shaft 3 and coupled to the wagons 4 in such a way that the sliding-head 10 leads when the blind is being drawn.

The control mechanism 9 comprises a rotatable handle 1 1 which is dependant from a resiliently flexible lug 12 extending longitudinally from the side of the sliding-head 10 opposite the wagons 4.

The upper end 1 1A of the handle 1 1 is rotatably housed within a socket 13 of the lug 12 and is drivingly connected to the operating shaft 3 by means of a Bowden cable 14. The Bowden cable 14 transmits the rotation of the handle 11 to the operating shaft 3 by means of a pair of externallytoothed spur gears 15, 16 housed within the sliding-head 10 and splined to respective ends of the cable 14 and shaft 3. The gears 15, 16 transmit the torque required to effect the amount of operating shaft rotation necessary to change the angular pitch of the blind slats 6 in response to only one or two revolutions of the handle 1 1.

Alternatively a direct drive connection may be made between the handle 11 and the shaft 3 through the Bowden cable 14, but this would require a number of turns of the handle 1 1 to effect the necessary rotation of the shaft.

The blind is drawn simply by using the handle 1 1 to slide the sliding-head 10 and the wagons 4 along the operating shaft 3. The sliding-head 10 and the wagons 4 are interconnected by couplings 11 which are extendable by a predetermined amount in one direction of sliding, so as to ensure the sliding-head and the wagons are pulled, in succession, to regularly spaced-apart positions along the shaft 3 as the blind is drawn. As shown in Figure 1 , the couplings 17 are formed by hooked strips which are arranged so that, after sliding the distance determined by the length of the strip, the sliding-head 10 engages the hook of the strip attached to the succeeding wagon 4, causing the latter to be pulled into engagement with the next hook, and so on until all the wagons 4 are evenly spaced along the shaft 3.

In some embodiments the sliding-head may be provided with a slat suspender, but it is envisaged that, in most cases, the sliding-head will not carry a slat 6 and will be closely connected to the adjacent, leading, wagon 4. In a simple embodiment (not shown) the couplings 17 may be formed by cords.

The lug 12 on the sliding-head 10 is provided with a downwardly facing notched projection 18 which, when the blind is drawn, snap-engages in a co-operating aperture 19 in the adjacent bearing block 2 to retain the blind in this drawn position.

To release the sliding-head prior to opening the blind the handle 1 1 is simply lifted to disengage the projection 18 from the aperture 1 9 by flexure of the lug 12.

A control mechanism according to the present invention is simpler than known mechanisms, and more suited to the "do-it-yourself" market, since the whole mechanism is self-contained and slides with the blind, thereby obviating the need for a cord-and-pulley system for drawing the blind.

Production costs can be kept at a minimum by using existing components: for example, the sliding-head 10 may be modified from a wagon 4 and the spur gears 15, 16 may employ worm wheels 8 of the type used for the wagon transmission means.

Claims

1. A control mechanism for a vertical slat blind of the type comprising: - an elongate head-rail; - an operating shaft extending parallel to the head-rail and supported by the latter for rotation by the control mechanism; - aplurality of wagons each captive on and slidable along the operating shaft, and carrying a respective blind slat suspender for rotation about a substantially vertical axis, the wagons being guided by the head-rail when the blind is being opened or drawn;; - a drive transmission means carried by each wagon for transmitting rotation from the shaft to the slat suspender, and - couplings which interconnect adjacent wagons, the couplings being extendable by a predetermined amount in one direction of wagon sliding so as to ensure that the wagons are pulled to regularly spaced-apart positions along the shaft when the blind is drawn, wherein the control mechanism is carried by a sliding-head which is coupled to the leading wagon, so as to lead the wagons when the blind is being drawn, and has a dependant handle by which a user effects sliding of the wagons, the handle being drivingly connected to the operating shaft to effect rotation of the latter

2.A control mechanism as claimed in Claim 1, in which the drive transmission means carried by the wagons comprise worm gears, the worms of which are carried by the slat suspenders.

3. A control mechanism as claimed in Claim 2, in which the operating shaft is splined, the splines meshing with the worms to act as worm wheels.

4. A control mechanism as claimed in Claim 2, in which the operating shaft is splined and the worm wheels of said worm gears are splined to the shaft.

5. A control mechanism as claimed in Claim 1, in which the drive connection between the handle and the operating shaft is effected by a Bowden cable which is attached to the handle and acts on the shaft through spur gears mounted in the sliding-head.

6. A control mechanism as claimed in Claim 5, in which the spur gears have externally meshing wheels, one wheel being attached to the operating shaft.

7. A control mechanism as claimed in Claim 1, in which the sliding-head is closely connected with adjacent, leading, wagon and slides on the operating shaft.

8. A control mechanism as claimed in any preceding claim, in which the handle depends from a resiliently flexible lug extending longitudinally from the end of the sliding-head opposite the wagons, the lug being adapted for snap-engagement with fixed detent means to retain the blind in its drawn position, disengagement of the lug from said detent means for opening the blind being effected by flexure of the lug upon lifting of the handle.

9. A control mechanism as claimed in Claim 8, in which the fixed detent means for engaging the lug comprise an aperture formed in a respective bearing block of a pair of bearing blocks mounted at the ends of the head-rail to support the operating shaft.

10. A control mechanism as claimed in Claim 1, in which the couplings comprise respective hooked strips which are arranged so that, when the sliding head is drawn in said one direction it engages the hook of the strip on the immediately succeeding wagon, and the following wagons are entrained in succession.

11. A control mechanism for a vertical slat blind, substantially as herein described with reference to, and as shown in, the accompanying drawings.

12. A vertical slat blind incorporating a control mechanism as claimed in any preceding claim.