MOTORISED ROLLER BLINDS

Abstract: In a motorised roller blind the motor (9) is received within the hollow end of the blind, drive being effected via shaft (14) and roller (15) with radial protuberance (16) locating in a slot within the blind. The motor (9) is received in a housing (8) around which is a bearing (12) for the end of the blind. A limit switch (11) switches off the motor automatically when the blind has reached the height of its travel and the lath of the blind impinges upon the wire probe (20) to cause the switch to be actuated.

Description: Motorised Roller Blinds •This invention relates to electrically driven roller blinds of the kind in which the electric driving motor is housed substantially within the roller or a tubular extension thereof. A number of prior roller blinds of the kind mentioned have been proposed, but all have had various drawbacks or operating disadvantages. For example, in French specification No. 2 493 906 (Baldanello and Zottino) is described a roller blind in which a drive motor and associated gearing is fixedly housed within a tubular holder which supports one end of the hollow roller. The motor shaft is drivingly connected to a disc fixed within the roller. Settable limit switches are disposed in a lateral housing which are actuable by counting devices turned by a cogwheel itself driven by a planet gear and an annular ring fixed in the end of the roller. Whilst being simple to set and operate, the arrangement is extremely complicated and expensive to manufacture. There is little or no tolerance for accommodating misalignment of the roller. Furthermore the arrangement does not lend itself to being scaled down to be adapted for window blinds. French specification No. 2 412 484 (Societe Industrielle du Metal Usine) and German Offenlegungschrift No. 32 20 441 (Seitz) both disclose roller blinds of the kind described with provision for automatic stopping of rotation at presettable limits of movement; however the mechanism for achieving this consists of settable riders threadedly engaged with a rotating threaded rod and actuating respective ones of a pair of limit switches. This arrangement is cumbersome and expensive, and does not lend itself to being scaled down to be adapted for window blinds. German Offenlegungschrift No. 32 31 684 (Baumeister & Ostler) discloses a blind of the kind described which is suitable for a window, in particular a car window. In this case however the motor is fixed within the roller at one end, which creates problems of twisting of the electric wire which leads out of the other end of the roller. Furthermore, no limit switches are provided for automatic operation. It is an object of the present invention to provide ■ a roller blind of the kind described which is adapted for use as a window blind and which does not suffer from the disadvantages and drawbacks mentioned above. According to the invention there is provided a roller blind of the kind described in which the electric driving motor is fastened to an end support bracket and is freely received with a clearance in a tubular end of the roller the motor shaft being drivingly connected to the roller to rotate the roller around the motor. This arrangement has the following several advantages:- (i) The construction is relatively simple, leading to easier assembly and considerably reduced production costs. (ii) The motor is static so there is no difficulty with power supply connections or twisting of wires. (iii) Installation of the roller blind is relatively straightforward. The free reception of the motor in the roller enables ready connection of the roller to the bracket by the end user. (iv) The clearance enables misalignment of the motor with the roller to be tolerated. This is an important advantage where the blind is to be installed by an unskilled person who may not be able to align the parts perfectly. (v) Raising and lowering of the blind may be accomplished by a flick of a switch, mounted if desired close to the window or remote therefrom, for example next to the light switch by the door of a room. (vi) The use of a low voltage motor which is supplied through a transformer reducing high voltage mains supply to a low voltage of 12/18 volts and a low amperage eases installation and makes the invention safe to use in the home and ensures it conforms with the various National Electrical Appliance Safety regulations and criteria around the. world. (vii) Room installations where more than one blind is used can, with the necessary electrical wiring and relays be simultaneously operated from one point with a tumbler switch for each blind. (viii) Blinds in an inaccessible position, such as behind a kitchen sink, can be operated by persons of small stature who would otherwise be unable to reach a raised blind. Presently preferred features of the invention are as follows:- (i) There may also be mounted on said bracket a limit switch actuated by a probe which is impinged upon by the blind's lath. Thus when the blind has been rolled up by the required amount, the lath impinges on the probe which switches off the power to the motor. This direct means of limiting the blind's rotation is virtually foolproof and is far simpler and more effective than the complicated geared devices mentioned above. Furthermore the switch can be mounted adjacent to the motor for a compact arrangement and minimum wiring. (ii) The probe may comprise a length of wire one end of which is bent to an elongate U-shape through which an edge of the blind runs. (iii) The motor may be push-fitted in a tub.ular housing which may itself be welded or otherwise fixed to or integral wi'th the bracket. This method of attachment is considerably more economic in terms of materials and assembly time than the complicated fixtures referred to above. (iv) There may be provided around the tubular housing a bearing for the end of the roller. The bearing may be for example a plastics ring having antifrictional properties, or indeed a roller or needle bearing cage. Alternatively the bearing could be fixed inside the end of the roller, (v) The bracket, and the complementary bracket for the other end of the roller, may be a slide fit into wall-mounting brackets. The advantage of this is the ease of installation. Once the wall-mounting brackets are fixed in place, the other brackets are simply presented to and engaged with the ends of the roller and the assembly may be slid easily into engagement with the brackets fixed on the wall. The roller brackets are preferably in the form of rectangular plates, and the wall- mounting brackets may be generally similar but having inturned flanges to locate the roller brackets. (vi) The motor shaft may have a connected roller with a radial protruberance for reception in a slot in a ring inside the roller to effect the drive. The advantage of this is that again misalignment of the motor with the roller is tolerated since the drive will not be disconnected despite several degrees of misalignment or indeed some lateral displacement of the motor with respect to the roller. In order that the invention may be readily understood,, an embodiment thereof will now be described by way of example with reference to the accompanying drawings in which:- Fig. 1 is a perspective overall view from above of a blind according to the invention; Fig. 2 is a perspective view of the operative end; and Fig. 3 is a sectional view of the operative end. The roller 1 is in the form of a hollow tube rotatably borne between two roller brackets 2, 3. Around the tube is wound a blind 4 of plasticised textile material, holland blind fabric or the like weighted and kept plain by a bottom rail 5. The roller/bracket assembly is fixed to a wall or window surround by mounting brackets 6 which are screw-fixed as shown. The main webs of brackets 6 are of generally similar shape and size to brackets 2, 3 but have inturned flanges 7 within which brackets 2, 3 slide and are received as shown. Fixed to bracket 2 by screws, welds or the like is a tubular housing 8 in which is push-fitted an electric motor 9 whose power is supplied by wire 10 from limit switch 11 (shown with cover removed). A nylon ring 12 surrounding housing 8 serves as a bearing for the open end of the roller tube 13- As shown in Fig. 3 the ring 12 has a convex outer surface to prevent misalignment of roller tube with the motor housing 8 creating undue friction. The drive shaft 14 of the motor 9 has fixed to it a roller 15 formed with a radial protruberance 16 which engages in one of two slots 17" formed in a ring 18 fixed in the tube 13 by grub screw 19- This engagement -transmits drive from the motor 9 to the tube 13 causing the blind to wind or unwind as the case may be. The rotary bearing at the operative end is formed by ring 12 and the bearing at the other end (not shown) is a conventional stub spindle engaged in a registering aperture formed in the bracket. It will be seen that the motor is freely received with a clearance in the tubular end of the roller; this enables misalignment of the roller to be tolerated without fouling of the motor. Furthermore it enables ready assembly of the motor into the roller and it should be noted that the assembly is not held together by fasteners, but by the location and reception of brackets 2, 3 in brackets 7, fixed there by grub screws 20. It has been found that with a suitable low voltage motor the arrangement disclosed provides a surprisingly quiet and smooth operation of the blind, and an acceptable speed of rotation. Raising of the blind is automatically stopped when complete by the limit switch 11 cutting off the power supply to the motor 9- This is accomplished by a depending wire probe 20 the lower end of which is formed into an elongate U-shape embracing the blind 4. The upper end of the probe is slidingly received in a guide 21 in which it is biassed downwardly by means of a coil spring 22. The bent back end 23 of the probe impinges on the leaf of a conventional microswitch 24 when the lath 5 of the blind impinges on the probe 20 to li: it upwards thereby operating the switch. It should be noted that no lower limit switch is required to stop the motor when the blind reaches its bottom point. Should the motor inadvertently remain operating the roller on continued rotation in the same direction will merely cause the blind to be rolled up the other way and the lath 5 will eventually reach the probe 20 to shut off the motor 9. It will be appreciated that the roller blind herein disclosed represents a considerable advance in the art in terms of simplicity of manufacture and operation whilst retaining the operational features of the more complicated blinds discussed above.

Claims: CLAIMS : 1. An electrically driven roller blind of the kind in which the electric driving motor is housed substantially within the roller or a tubular extension thereof in which the motor is fastened to an end support bracket and is freely received with a clearance in a tubular end of the roller the motor shaft being drivingly connected to the roller to rotate the roller around the motor. 2. A roller blind according to claim 1 in which there is mounted on said bracket a limit switch actuated by a probe which is impringed upon by the blind's lath. 3 - roller blind according to claim 2 in which the probe comprises a length of wire one end of which is bent to an elongate U-shape through which an edge of the blind runs. 4. A roller blind according to claim 1 , 2 or 3 in which the motor is push-fitted in a tubular housing which is welded or otherwise fixed to or integral with the bracket. 5. A roller blind according to claim 4 in which a bearing for the end of the roller is provided around the tubular housing. i 6. A roller blind according to any of the preceding blinds in which the motor shaft has a connected roller with a radial protuberance for reception in a slot in a ring inside the roller to effect the drive. 7. A roller blind according to any of the preceding claims in which the bracket and the complementary bracket for the other end of the roller are slidably fitted into wall-mounting brackets.

Inventors: ELLIOTT MICHAEL HAMILTON, GLATZEL DONALD LAWRENCE, ELLIOTT, MICHAEL, HAMILTON, GLATZEL, DONALD, LAWRENCE
Applicants: ELLIOTT MICHAEL HAMILTON, GLATZEL DONALD LAWRENCE, ELLIOTT, MICHAEL, HAMILTON, GLATZEL, DONALD, LAWRENCE
Application year: 1985
Main classification: E06B9
IPC codes: E06B9