AU617020B2

AU617020B2 - Drive mechanism for venetian blind

Info

Publication number: AU617020B2
Application number: AU45920/89A
Authority: AU
Inventors: Herman Oskam
Original assignee: Hunter Douglas International NV
Current assignee: Hunter Douglas International NV
Priority date: 1988-12-06
Filing date: 1989-12-05
Publication date: 1991-11-14
Anticipated expiration: 2009-12-05
Also published as: EP0372803B1; ES2032112T3; DE68901764T2; MY104287A; AU4592089A; GB2225803A; GB2225803B; GB8828403D0; SG15693G; ATE77126T1; NZ231620A; DE68901764D1; EP0372803A1

Abstract

A venetian blind and drive mechanism (52) therefore, in which the drive shaft (68) passes through the headrail (20) of a blind, is rotated by an epicyclic gear train (50) which may be mounted on the front of the venetian blind headrail.

Description

Ab COMMONWEALTH OF AUSTRALIA FORM 617020 PATENTS ACT 1952 COMPLETE S P E C I F ICAT IO N FOR OFFICE USE: Class Application Number: Lodged: Int.Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: SHELSTON WATERS, HUNTER DOUGLAS INTERNATIONAL

N.V.

Kaya Flamboyan 11, Willemstad, Cvsacao, Netherlands Antilles Herman Oskam 55 Clarence Street, Sydney 4ag 4 4I Complete Specification for the Invention entitled: "DRIVE MECHANISM FOR VENETIAN BLIND" The following statement is a full description of this invention, including the best method of performing it known to us:- 1 A f 1 -la- The present invention relates to venetian blinds and drive mechanisms therefor.

Traditionally venetian blinds are formed with a headrail, usually of channel cross-section, in which is mounted an operating mechanism controlled by a longitudinally extending drive shaft. This drive shaft may be used to raise and lower the slats of the blind and/or may be used to tilt the slats. The drive shaft is itself driven usually via a gear box which may be controlled, for example, by a bead chain or by a rotatable wand.

In relatively narrow venetian blinds using reduced dimensioned headrails, gear boxes to reduce the effort in raising and lowering the blind are not readily available, so it has been customary with such small headrail systems to o'0o 15 revert to a crank rod to operate the winding mechanism. One 0000 0 problem with such a crank drive is that it looks 0 00 0o 0 inappropriate on a blind having such slender dimensions and 09 ;0 it would be very desirable to be able to use a ball cord or 0000oo a ball chain as an operating element.

It is now proposed, according to the present invention, to provide a venetian blind including a head 00 I 000 0 rail, a drive shaft for raising and lowering the slats of 9 a 0 the blind, a drive gear mechanism for rotating said drive o"o shaft, said drive gear mechanism comprising a housing, means 25 to mount the housing on the exterior of a venetian blind o head rail, the rea:. face of the housing being engageable

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1 2 with said head rail, a manually operable drive member mounted for rotation in said housing, a driven shaft extending rearwardly outwardly of said housing and an epicyclic gear train operatively connecting said drive member and said driven shaft and a direction changing gear train, such as a bevel gear train, connecting the driven shaft of the drive mechanism to the drive shaft of the venetian blind.

The epicyclic gear train can be made very compact and can give a substantial gear reduction to make operation of the blind easy.

In a preferred construction the housing has formed 0o o: internally thereof, the ring gear of an epicyclic gear train. A further improvement in the efficiency can be 0 15 achieved by the planet carrier of the epicyclic gear train including a bearing for the drive member which may be in the form of a bead chain pulley. With this arrangement, the bead chain pulley and the driven shaft both rotate in the 004same rotational sense, while the difference in rotational 20 speed is less than it would have been if the chain wheel had o"4 been journalled on a fixed shaft. In this way certain friction losses are thus reduced.

0 00 4,0 If desired, the direction changing gear train, °o such as the bevel gear train, can include a braking means for holding the blind in a raised position.

The invention also provides a drive mechanism for rotating the drive shaft of a venetian blind, which dr'.ve shaft is used for raising and lowering the slats of the blind, said drive gear mechanism comprising a housing, means to mount housing on the exterior of the venetian blind headrail, the rear face of the housing being engageable with said headrail, and manually operable drive member mounted for rotation in said housing, a driven shaft extending rearwardly outwardly of the housing and an anti-cycle gear chain operatively connecting said drive member and said RA 0> 2a 2a driven shaft and a direction changing gear, such as a bevel gear chain, adapted to connect the driven shaft of the drive mechanism to the drive shaft of the venetian blind.

In order that the prese .t invention may more readily be understood, the following description is given, merely by A

OT

-3way of example, reference being made to the accompanying drawings in which:- Figure 1 is a perspective view of one embodiment of Venetian blind according to the present invention; Figure 2 is an enlarged cross-section to the headrail of the blind showing the drive gear mechanism; and Figure 3 is a schematic exploded view of the drive gear mechanism of Figure 2.

Referring first to Figure 1, there is illustrated therein one embodiment of venetian blind according to the present invention, including a headrail 10, a bottom rail 12 supported by lift cords 14 and a plurality of slats 16 supported by ladder means 18. Conventional raising and tilting mechanisms 20 are provided for raising and lowering the bottom rail 12 and for lifting the slats 16; these mechanisms are shown provided with a cover 22 and are 0000 00o themselves rotated by a drive shaft 24.

00 a 0'Rotation of the drive shaft 24 is effected by a 00 drive mechanism 26. The drive shaft includes a central 0 0.

oo° 20 screwthreaded spindle 28 carrying end stops 30 and 32 and a 0000 translating nut element 34, the elements 28 to 34 being utilized to control the amount of raising and lowering of o the blind in a manner with which the present invention is o o o not concerned.

If reference is now made to Figures 2 and 3, the 00 drive mechanism, indicated with the general reference numeral 26, includes a housing 36 having, adjacent its lower 0 0o i: -4rear edge, a rearwardly extending finger 38 and adjacent its upper rear edge a rearwardly extending hook 40. The hook can be engaged over the bead 42 of the front flange 44 of the headrail 10 and the finger 38 can be secured by a self tapping screw 46 engaged in a hole in the web portion 48 of the headrail 10 to hold the housing 36 on the front of the headrail 10. An inner surface of the housing 36 is formed with a ring gear 50 of an epicyclic gear train indicated by the general reference numeral 52. This gear train includes a planet carrier 54 mounted for rotation on a stub shaft 56.

The planet carrier has three rotatably mounted planet gears 58 thereon, which mesh with the ring gear 50 and also mesh with a sun gear 60. This sun gear itself is journalled on a driven shaft 62 integral with the planet carrier 54. The sun gear is formed integrally with a bead chain pulley 64 carrying a manually operable bead chain 66, (Figure 1).

As can be seen again in Figures 2 and 3, the driven 2 shaft 62 has a hexagonal end portion 68 engageable in a direction changing gear train 70 as seen in Figure 1.

It will be appreciated, therefore, that in use, operation of the bead chain will cause the pulley 64 to rotate, this rotating the sun gear 60. The planet gears 58 will be rotated thereby, because they mesh with the ring *gear 50, the planet carrier 54 and therefore the driven shaft 62, 68, will rotate, thereby rotating the drive shaft t 24 via the bevel gear train Such a structure is very compact and provides an 1 efficient gear reduction ratio, for example of 3 tc 1, so that the blind can be operated in an easy manner.

S. 4

Claims

1. A venetian blind including a head rail, a drive shaft for raising and lowering the slats of the blind, a drive gear mechanism for rotating said drive shaft, said drive gear mechanism comprising a housing, means to mount the housing on the exterior of a venetian blind head rail, the rear face of the housing being engageable v'th said head rail, a manually operable drive member mounted for rotation in said housing, a driven shaft extending rearwardly outwardly of said housing and an epicyclic gear train operatively connecting said drive member and said driven shaft and a direction changing gear train, O such as a bevel gear train, connecting the driven shaft of the drive mechanism to the drive shaft of the venetian blind.

2. A venetian blind according to claim 1, wherein said housing has formed internally thereof the ring gear of the epicyclic gear train. o 3. A venetian blind according to claim 1 or 2, wherein 00 0 a planet carrier of the epicyclic gear train includes a bearing for the drive member.

4. A venetian blind according to claim 1, 2 or 3, wherein the drive member comprises a bead chain pulley. A venetian blind according to any preceding claim, wherein the housing includes rearwardly extending hook-shaped elements adapted to hook onto the venetian blind head rail, so that the housing is located in front of the head rail. V

7- 6. A venetian blind according tr any preceding claim, wherein said drive shaft is a combined drive shaft for raising and lowering and for tilting the slats of the blind. 7. A venetian blind substantially as hereinbefore described, with reference to, and as illustrated in the accompanying drawings.

8. A drive mechanism for rotating the drive shaft of a venetian blind, which drive shaft is used for raising and lowering the slats of the blind, said drive gear 0 o °mechanism comprising a housing, means to mount housing on the exterior of the venetian blind head rail, the rear 0 face of the housing being engageable with said head rail, 00o and manually operable drive member mounted for rotation in said housing, a driven shaft extending rearwardly outwardly of the housing and an anti-cycle gear chain 10 operatively connecting said drive member and said driven shaft and a direction changing gear, sEuch as a bevel gear chain, adapted to connect the driven shaft of the drive °o mechanism to the drive shaft of the venetian blind.

9. A drive mechanism for a venetian blind, said drive mechanism being substantially as hereinbefore described, with reference to, and as illustrated in the accompanying drawings. DATED this 22nd day of August 1991 HUNTER DOUGLAS INTERNATIONAL N.V. Attorney: PETER HEATHCOTE Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS