This invention relates to retractable coverings for architectural openings, and more particularly, an operating system for controlling retractable coverings for architectural openings using a single operating element for manual actuation. The present invention provides for a retractable coverings for architectural openings utilizing a control system having a single operating element allowing a user to move a retractable covering for architectural openings between extended and retracted positions by imparting a repetitive motion to the operating element. When the retractable covering is disposed vertically, a user can raise or lower the retractable covering by imparting a repetitive up and down motion to the pull cord.

Examples of such coverings are known from e.g. EP 1455049, EP 1728963, and WO 2008/094720 where an operating cord can be pulled from an operating cord spool and a spring motor in the spool retracts the cord such that a repetitive pull cord motion is possible. The operating spool drives an input assembly. The direction and position in which the pull cord is manipulated will engage a shift arm which acts on the input assembly and together with additional means dictates the direction of rotation of an output means relative to the direction of rotation of the input assembly.

As described in EP 1455049 the input assembly includes a planetary gear transmission with a sun gear integrally connected to the operating pull cord spool, a planet carrier with planet gears, a spider and a ring gear. When a user pulls the cord from the operating spool, which represents a first motion transfer element, the spool rotates in counter clockwise direction. Because the sun gear is integral with the operating spool it also rotates in counter clockwise direction. When a user pulls the operating cord in a first angularly deflected direction (i.e. at an angle with respect to the vertical direction) to lift the shade, a shift arm pivots and a pawl tooth engages ratchet teeth on an outer circumference of the planet carrier, which prevents the planet carrier from rotating. The counter clockwise rotation of the sun gear now causes clockwise rotation of the planet gears, which in turn engage the ring gear - acting as a second motion transfer element - to turn in a clockwise direction. When the user pulls the operating cord in a second angular direction the shift arm does not pivot and the planet carrier is allowed to rotate, which it does in counter clockwise direction. By rotating in counter clockwise direction the planet carrier engaged the spider to turn in counter clockwise direction and the spider acts as a one-way clutch and engages the ring gear in counter clockwise rotation.

Thus the transmission is operative to translate rotation of the input sun gear into either the same direction or the opposite direction of rotation of the output ring gear by a combination of the shift arm and the spider, which together dictate the direction of rotation of the ring gear relative to the direction of rotation of the sun gear. A drawback of this system is that for the spider to be able to engage the ring gear the ring gear requires a special shape because the spider will engage an inner toothed rim of the ring gear with one or more of its legs. The ring gear thus needs to surround at least that part of the planet carrier which carries the spider. This results in a relatively large outer diameter of the transmission and thus of the input/output assemblies. For window coverings other than roller blinds the space, such as space provided in a head rail, is generally very limited and constrained.

It is therefore an object of the invention to provide a control system having a single operating element allowing a user to move a retractable covering for architectural openings between extended and retracted positions by imparting a repetitive motion to the operating element that allows a convenient small outer diameter such that it can also fit within head rails, or other confined spaces of window coverings other than roller blinds. Accordingly it is an object of the present invention to propose an improved control unit and system for the operation of coverings for architectural openings. In a more general sense it is thus an object of the invention to overcome or ameliorate at least one of the disadvantages of the prior art. It is also an object of the present invention to provide alternative structures which are less cumbersome in assembly and operation and which moreover can be made relatively inexpensively.

Alternatively it is also an object of the invention to at least provide the public with a useful choice.

To this end the invention provides a control unit for rotationally driving, in a selected one of rotationally opposite directions, a mechanism for moving a covering for an architectural opening between extended and retracted positions, the control unit including:

a housing having a generally cylindrical cavity therein;

a single operating element enabling operation by manually imparting a repetitive linear motion thereto;

a rotational input member for engagement by the single operating element and journalled with respect to the cylindrical cavity for rotation movement between first and second rotational positions;

a return mechanism for returning the rotational input member from the second rotational position back to the first rotational position;

a sun gear driven by the first rotational element and positioned substantially concentrically with respect to the cylindrical cavity;

a planet carrier and a plurality of planet gears engaged by the sun wheel; a ring gear engaged by the planet gears, the planet gears being each rotationally supported on the planet carrier and the planet carrier and ring gear being each rotationally supported with respect to the cylindrical cavity; a rotational output member, adapted to be driven by the ring gear; and control means operative to translate rotation of the sun gear in rotation of the ring gear in one of rotation in the same direction and rotation in an opposite direction with respect to rotation of the sun gear, wherein the direction of rotation is dictated by selective operating the single operating element in one of a first position of angular deflection and in a second position of angular deflection.

Advantageously the control means further includes a shift arm rotationally supported about an axis parallel to the axis of rotation of the rotational input member, the shift arm being adapted to be engaged by the single operating element in the first position of angular deflection, so as to cause engagement with the planet carrier to arrest the planet carrier in a stationary position and adapted to be disengaged by the single operating element in a second position of angular deflection, so as to allow rotation of the planet carrier. It is thereby further advantageous when the shift element can be engaged by the single operating element, upon manual actuation thereof, in a first angular direction to hold the planet carrier stationary and in a second angular direction to allow the planet carrier to rotate.

A particularly advantageous embodiment will be obtained when a switch ring is operatively engaged between the planet carrier and the ring gear to couple the planet carrier to the ring gear in one of opposite rotational directions, thereby the rotational output member rotates in the same direction as the rotational input member when the planet carrier is coupled to the ring gear and rotates in a direction opposite thereto, when the planet carrier is held stationary. Furthermore it will be advantageous in such an arrangement, when the switch ring is brought into and out of engagement with the ring gear by moving in an axial direction through rotation of the planet carrier. Such a control unit can advantageously also be arranged to have the planet carrier comprise a helical track on a perimeter thereof, and provide the switch ring with a protrusion engaging the helical track of the planet carrier. Thereby rotation of the planet carrier urges the switch ring into axial engagement with the ring gear, whereupon the planet carrier and the ring gear rotate together in the same rotational sense as the rotational input member. The control unit can be further improved when the shift arm has a pawl tooth adapted to engage with ratchet teeth on an outer circumference of the planet carrier.

In another advantageous arrangement the switch ring has a first set of ratchet teeth on an axial face thereof facing an axial end of the ring gear, and wherein the ring gear has a complementary set of ratchet teeth on its axial end facing the set of ratchet teeth on the switch ring.

The single operating element can advantageously be a flexible element and the rotational input member can be an operating cord spool for storable receipt of windings of the operating element. In this particular arrangement the sun gear may project from an axial end surface of the operating cord spool.

The control unit may be further improved by the return mechanism including a coil spring.

The control unit may also advantageously further include an automatic brake mechanism operatively engaged between the cylindrical cavity and each of the ring gear and the rotational driven member. In particular such an automatic brake mechanism may include a wrap spring. The control unit according to the invention may further benefit from the ring gear being shaped as a cylindrical body comprising a toothed inner

circumferential surface for cooperation with the planet gears.

The invention also includes a covering for an architectural opening including: at least one covering that is retractable and extendible by a mechanism for moving the at least one covering member between extended and retracted positions, and a control unit of the invention. Such a covering may be advantageously improved when the mechanism for moving comprises a system for winding and unwinding at least one lift cord onto and from a cord spool by driving the cord spool in a first direction or a second direction by the control unit. Further aspects and advantages of the invention will be apparent from the detailed description below of particular embodiments and drawings threof, in which:

Figure 1 is a schematic view of a window covering with a head rail depicted partially depicted open to show the control system according to the invention;

Figure 2 is a perspective view showing the control unit in isolation;

Figure 3 is an exploded view of the control system of the invention;

Figure 4 is a cross- sectional view of the control system of the invention; and

Figure 5 is a partial detail view of the operating cord, operating spool, and shift arm. Figure 1 shows a roman shade 1 with head rail 3 in which on a driven shaft 5 a pair of left and right lift cord spools are mounted 7, 9. The shade further includes shade material 11, a bottom bar 13 and a pair of left and right lift cords 15, 17. Each lift cord is connected with a first end 15A, 17A to the respective left or right lift cord spools 7, 9 and with another end 15B, 17B to the bottom bar 13. When the lift cord spools 7, 9 are driven to rotate in a first direction to lift the bottom bar 13 and retract the shade material 11, the left and right cords 15, 17 are wound about the respective left and right spools 7, 9 and the shade is lifted or retracted. When the lift cord spools 7, 9 are driven to rotate in a second, opposite direction the lift cords 15, 17 will be unwound from the spools 7, 9 and the bottom rail 13 will be lowered and the shade material 11 extended. In order to drive the lift cord spools 7, 9 a control unit 19 is mounted in the head rail and drivingly connected to one end of the driven shaft 5. The control system includes a housing 21 and an opening 23 through which an operating cord 25 extends. The operating cord includes an operating length 25A and a manipulating length 25B separated by a stopper 27. The stopper prevents the manipulating length 25B of the operating cord being retracted into the housing 21 and onto the operating cord spool (not shown in this Figure). The manipulating length 25B of the operating cord 25 is provided at its free end with a tassel 29.

In Figure 2 the control unit 19 is shown separate from the head rail and roman shade of Figure 1. The control unit 19 has a substantial cylindrical housing 21. The operating cord 25 extends with its operating end 25A from the opening 23 of a cord guide 33 attached to the housing 21. Left and right hand end caps 24, 26 close off the axial ends of housing 21 and a rotational output member 30 for driving the driven shaft 5, protrudes axially from the left hand end cap 24. The left hand end cap 24 has arms 28 extending axially over the outer

circumference of cylindrical housing 21 and are adapted to fit snugly inside of the head rail 3. The control unit 19 is shown further in an exploded view in Figure 3. The control unit 19 includes housing 21 which is a generally cylindrical hollow body having a left 21 A and a right end 2 IB to which the left and right end caps 24, 26 can be mounted. The left end cap has axially extending arms 28 which snap onto protrusions 29 on the outer circumference of the housing and thus secure the end cap to the housing. In the housing adjacent its right end 2 IB a cut-out 31 is provided for receiving the cord guide 33 therein. The cord guide 33 thereby is mounted adjacent to the operating cord spool 35. The operating cord spool 35 is a cylindrical body having an outer circumference 37 about which the operating cord 25 can be wound. In further reference to Figure 3 and starting from the right hand end, it is seen that the right end cap 26 houses a clock spring 39. The clock spring is effective in biasing the operating cord spool 35 to a first end position in which the operating cord 25 is would with its operating length 25A onto the outer circumference 37 of the cord spool 35. Between the operating cord spool 35 and the cord guide 33 the operating length 25A of the operating cord 25 is guided over a shift arm 41. The shift arm 41 is pivotaUy mounted on a shaft 43. A sun gear 45 extends axially of the operating cord spool 25 and may be guided by an optional bearing plate 47 before extending centrally through a planet carrier 49.

The planet carrier 49 has a plurality of shafts 51 for rotatively receiving an equal number of planet gears 53. The shafts 51 are separated by posts 55. The shafts 51 and posts 55 have their free ends engaged by an annular cage 57. The planet carrier has radial ratchet teeth 59 on axial right hand end thereof. Immediately to the axial left of the ratchet teeth 59 the planet carrier cylindrical boss 61 on which perimeter surface helical tracks in the form of helix grooves 63 are formed. A switch ring 65 is rotatively received about the cylindrical boss 61. The switch ring 65 has inwardly projecting fingers 67 (three of which are visible in Figure 3), for engaging the helix grooves 63. On an axial left hand face thereof the switch ring 65 is provided with axial ratchet teeth 69. The axial ratchet teeth 69 of the switch ring 65 can engage complementary ratchet teeth 71 on a right hand axial end of a ring gear 73. The ring gear 73 has internal gear teeth (not visible in Figure 3, but conventional for planetary gear arrangements) that mesh with the planet gears 53 when the planet carrier 49 is inserted in its interior. The radial ratchet teeth 59 on the planet carrier 49 cooperate with a detent 75 on the shift arm 41. The planet carrier 73 on a left hand axial end thereof has opposite wrap spring contractor abutment surfaces 77, 79 to extend inwardly of a wrap spring 81. The rotational output member 30 has a wrap spring expanding finger 83 extending axially from a left hand axial end of the rotational output member 30. The wrap spring 81 in its relaxed state engages an inner circumferential surface of the housing 21. The entire assembly of Figure 3 in assembled condition is held together by the right hand and left hand end caps 24, 26. To this end the axially extending arms 28 of the left hand end cap 24 engage with the protrusions 29. Similarly the right hand end cap 26 has axially extending arms 85 engaging protrusions 87 on the outer surface of housing 21.

Figure 4 shows a longitudinal cross section of the control unit 19 in its assembled condition. It is easily seen that the operating cord spool 35, the planet carrier 49, ring gear 73 and output member 30 all fit snugly within the interior of the housing 21. As shown in Figure 4 the switch ring 65 is in axial engagement with the ring gear 73, through the complementary ratchet teeth 69, 71. In this position the switch ring 65 has its inwardly projecting fingers 67 (visible only in Figure 3) abutted against axially extending end surfaces of the relevant helix grooves 63. When the rotation of the planet carrier 49 that has caused engagement between the switch ring 65 and the ring gear 73 is continued in the same direction, then the planet gear will rotate together with the ring gear 73. This will be the rotational direction when the operating cord 25 is pulled and the operating cord spool 35 rotated by its unwinding there from. This rotational direction will also be used for lowering the bottom bar 13 and extend the shade material 11 to the position shown in Figure 1. The operating cord 25 is pulled in repetitive strokes and thereby only

incrementally rotates the ring gear 63 in the lowering direction. Rotation of the ring gear 73 in the lowering direction also causes the abutment surface 77 to engage an inwardly bend spring tang 81A (see Figure 3) of the wrap spring 81. Engagement of the spring tang 81 by the abutment surface 77 in the direction of lowering contracts the wrap spring 81 and disengages it from the inner surface of the housing 21. Further rotation of the abutment surface 77 also causes it to engage the finger 83 and thereby rotate the output member 30 in the same sense. Once the operating cord spool 35 has reached its second end position in which the operating length 25A of the operating cord has been fully unwound from its outer circumference 37, the operating cord 25 is relaxed and allowed to rewind itself under the action of the clock spring 39. During this movement the wrap spring 81 reengages the inner circumference of the housing 21. This will hold the shade material and bottom bar in the adjusted position. Should the weight of the adjusted shade and bottom rail be urging on the output member 30, this will only engage one of the inwardly bend spring tangs 81A, 81B of wrap spring 81 and thereby reinforce its grip on the inner surface of the housing 21 by further expanding the wrap spring 81. The wrap spring 81 thus functions as an automatic brake means to retain the shade in its adjusted position. While the output member 30 is kept stationary the operating cord spool 35 is returned to its first position by the clock spring 39 and the operating length 25A of the operating cord is rewound on the outer circumference 37 of the cord spool 35. During this reverse motion of the operating cord 25 and cord spool 35, the switch ring 65 is moved out of engagement with the ring gear 73 as it is being moved to the right by the helical grooves 63 acting on the inwardly directed fingers 67. In the first end position of the operating cord spool 35, the operating cord 25 can be

manipulated in two different ways.

Pulling the operating cord 25 in a first position of angular deflection will keep the shift arm 41 and its detent 75 disengaged from the radial ratchet teeth 59 of the planet carrier 49. This first position of the operating cord 25 is shown in dotted lines in Figure 3. Pulling in that first direction of angular deflection will effectively continue the lowering operation of the shade. As will be understood from Figures 3 and 5 in particular the operating cord 25 will engage a depending arm 89 on the shift arm 41 and thereby keep the detent 75 disengaged from the radial ratchet teeth 59 of the planet carrier 49.

Because the ratchet teeth 59 are not engaged by the detent 75 the planet carrier 49 is free to rotate and will move the switch ring 65 back into

engagement with the ring gear 73 and the above described lowering of the shade by further unwinding of the lift cords 15, 17 will continue.

However, from the first end position of the operating cord spool 35 it is also possible to pull the operating cord 25 in a second position of angular deflection. The second position of angular deflection of the operating cord 25 is shown in firm lines in Figures 3 and 5. In the second position of angular deflection the operating cord 25 is effective to bring the shift arm 41 and its detent 75 into engagement with the radial ratchet teeth 59 of the planet carrier 49. As seen in Figures 3 and 5, the operating cord 25 with its operating length 25A is routed behind a cylindrical portion of shaft arm 41, with which it is jounalled on its shaft 43. Frictional engagement of this cylindrical portion by the cord 25 will rotate the detent 75 in engagement with the ratchet teeth 59. This friction between the cylindrical portion and the cord will keep the planet carrier 49 stationary and the sun wheel 45 will now be allowed to rotate the planet gears 53 into opposite rotation. The stationary planet carrier 49 will also retain the switch gear 65 out of engagement from the ring gear 73. The ring gear 73 by rotation of the planet gear 53 on the stationary planet carrier 49 will now cause the ring gear 73 to rotate in an opposite direction with respect to the operating cord spool 35. Opposite rotation of the ring gear will bring abutment surface 79 thereof in engagement with inwardly bend spring tang 81B of the wrap spring 81. The wrap spring 81 will thereby be contracted and disengaged from the inner surface of housing 21. Rotation of the ring gear 73 in this direction will engage the finger 83 of the output member 30 and also rotate it in an opposite direction with the effect that the shade is raised by rewinding of the lift cords 15, 17 (see Figure 1). After a full pull of the operating cord 25 return of the operating cord spool 35 to its first end position, after relaxing of the operating cord 25 is similar for both modes of operation.

The mechanism just described is very effective in offering two modes of operation— i.e. lowering and raising— by a single operating element. It also offers an ergonomically optimal length of manual pull, that is independent of the size of the window covering. Furthermore the single depending cord element for operating the window covering offers child safety over the conventional looped operating cords.

Thus the invention discloses a control system having a single operating element allowing a user to move a retractable covering for architectural openings between extended and retracted positions by imparting a repetitive motion to the operating element including:

- an operating cord spool 35 associated with an operating element 25,

- the spool having an outer circumference 37 about which the operating element can be wound and an axial surface from which a first or sun gear 45 projects,

- the sun gear being part of a planetary gear transmission,

- the transmission further including a plurality of planet gears 53 on a planet carrier 49 and a ring gear 73,

- the ring gear having the shape of a cylindrical body comprising an inner circumferentially toothed ring-like surface acting as the ring gear for cooperation with the planet gears,

- an output assembly 30, 81 opera tively connected to said ring gear, and

- means for dictating the direction of rotation of the ring gear relative to the direction of rotation of the sun gear,

wherein said means comprise - a shift arm 41 pivotally supported on an axis parallel to the axis of rotation of the cord spool and adjacent the cord spool such that in operational friction between the operating element and the shift arm causes the shift arm to pivot and engage the planet carrier thus arresting the planet carrier against rotating,

- a switch ring 65 rotatably mounted on a helical track 63 formed on the outer circumference 61 of the planet carrier such that when the planet carrier rotates this rotation pushes the switch ring in axial direction towards the ring gear until the switch ring engages an axial end of the ring gear and thus couples the planet carrier to rotate as one with the ring gear body.

It is thus believed that the operation and construction of the present invention will be apparent from the foregoing description. The invention is not limited to any embodiment herein described and, within the purview of the skilled person; modifications are possible which should be considered within the scope of the appended claims. Equally all kinematic inversions are considered inherently disclosed and to be within the scope of the present invention. In the claims, any reference signs shall not be construed as limiting the claim. The term 'comprising' when used in this description or the appended claims should not be construed in an exclusive or exhaustive sense but rather in an inclusive sense. Thus the expression 'comprising' as used herein does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to Only one', but instead are used to mean 'at least one', and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. Expressions such as: "means for ..." should be read as: "component configured for ..." or "member constructed to ..." and should be construed to include equivalents for the structures disclosed. The use of expressions like: "critical", "preferred", "especially preferred" etc. is not intended to limit the invention. Features which are not specifically or explicitly described or claimed may be additionally included in the structure according to the present invention without deviating from its scope.