EP2550421B1 - Cord winder of a window shade - Google Patents

Description

The invention relates to a cord winder for a window covering device.

A cord retractor is equipped with sun protection, concealment or decoration devices arranged in front of bay windows and designated as "window covering devices". These devices are venetian blind type, boat blind, pleated blind, bubble blind or "Roman Shade". In a typical configuration of such a device, several corded reels are arranged in a box and can be driven simultaneously by a common drive shaft, using a manual winch or an electric motor. The cords are attached at one end to a load bar while the occultation, decoration or sun protection product is deployed in the space between the load bar and the box. The visible surface of the product is proportional to the course of the cord.

The prior art describes very many embodiments of cord reels, intended for this type of device. A real breakthrough in this field is the introduction of cord reels having functionally a winding zone of the cord, a means of thrusting the turns wound to a wound coil storage area, zone in which the tension of the turns of the cord has become substantially zero.

By physical effect called "capstan effect", the tension of the cord on a drum tends to decrease between a newly wound turn and a coil formerly wound. However, this effect is insufficient to allow a regular thrust of many turns on a purely cylindrical winding drum. The originally wound coils tend to hang on the drum, and new turns can not be inserted by pushing them. There is overlap of the turns. To prevent such an overlap from occurring, it has been invented to accentuate the capstan effect by further causing a gradual or abrupt variation in the diameter of the winding drum.

The patent US5,328,113 describes such a device, providing for a variation in diameter between a winding zone and a storage zone.

The patent US5,725,040 describes a means for thrusting the turns by a finger outside a winding drum.

Cord reels are, for the most part, equipped with a conical profile winding drum in the winding area.

However, there remains a problem mainly related to the meeting of an obstacle by the load bar, during a phase of unfolding the cord. Indeed, in this case the cord is no longer tensioned by the weight of the load bar. If the rotational movement of the drum continues in the direction of unwinding, the cord tends to give rise to loose turns whose diameter is increasing. These turns can then overlap and become entangled. The situation does not improve if the obstacle disappears suddenly: some reels of the device can resume a normal configuration while others will remain in a situation of wedging turns, resulting in a leaning of the load bar, which can not be compensated by a reverse movement of the winding. There is also a risk of wear and breakage of the cord.

The case of an obstacle is relatively rare, but the same phenomenon can occur during a "hard point" in a slide, by example when the window covering device is guided by lateral slides.

Several documents of the prior art attempt to remedy this kind of situation by adding a lid above the drum, so as to leave a limited space between the drum and the lid. Thus, it is intended to prevent the increase in diameter of the turns of the cord during unwinding, when the load applied to the cord is no longer sufficient. The patent US 7,137,430 and the patent US 7,159,635 describe such solutions.

Moreover, the patent 7159635 also discloses a means for movably securing the cord along the winding drum, as also described in the patent US7,370,683 .

These solutions improve the unwinding conditions of the cord but can not be enough to force the cord to leave the cord winder when no more tension is exerted on it by the load bar. There then remains the problem mentioned above, in a more or less serious form.

The problem also occurs occasionally during a winding phase if it happens that a false movement of an occupant of the room comes relieve the weight of the load bar: the devices of the prior art can not roll up a cord when it is not live. This constraint often pushes to increase the load bar and then results in unnecessary energy consumption and the need to oversize a drive motor.

Finally, such a false movement on the load bar can also occur in the absence of a winding or unwinding maneuver, and cause a rise of the cord in the reel and, for example, an overlap of turns. Such false movements can occur during cleaning periods of the premises or glazing.

There is however a need for cord reels with absolutely complete reliability. This is particularly the case for window covering devices arranged between two sealed windows, for which the slightest failure of the cord winder is prohibited. In this case, the false movements are not to be feared, but the problems mentioned above can simply come from hard points appearing over time in the guideways of the device.

The object of the invention is to provide a cord winder overcoming the above disadvantages and improving the cord reels known from the prior art. In particular, the invention improves the winding and unwinding of a blind suspension cord, avoiding any risk of entanglement thereof.

According to the invention, the cord winder of a window cover device comprises a winding drum of a cord adapted to be rotated about a first axis of revolution, a means of guiding the cord towards the winding drum, the winding drum being rotatably mounted in a support., The winder comprises a rotary roller mounted on the support according to a second axis of revolution and comprises a friction zone in which at least one turn the cord, wound on the winding drum, is in contact with the rotary roller.

The rotation of the rotary roller can be slaved to the rotation of the winding drum by a servo means.

The servo means may comprise a first pinion integral in rotation with the winding drum, and engaged with a second pinion integral in rotation with the rotary roller.

In the friction zone, the rotary roller may apply pressure to at least a first turn of the cord wound on the winding drum, for example the first turn and another turn or the first turn and two other turns.

The cord winder may comprise a means of orientation of the cord, secured to the support and disposed in the vicinity of the friction zone away from the guide means and less than two turns of cord a last turn in contact with the rotary roller.

The number of turns of the friction zone may be independent of the state of winding or unwinding of the bead.

A thrust means may act at least on the turns in contact with the rotary roller, away from the guide means.

The thrust means may be a helical wall.

The helical wall may be formed in a cylindrical bore of the support, said cylindrical bore containing at least the friction zone and the helical wall may be at least partially interrupted by a housing of the rotary roller.

The rotary roller may comprise two shaft ends, belonging for example to a secondary shaft, guided in the support, in particular by two straight grooves formed in the support.

Pressure means can push the rotating roller towards the drum.

The pressure means may comprise an elastic member of the support in contact with a shaft end of the rotary roller.

The rotary roller may comprise an elastomeric coating and / or a friction coating.

At most five consecutive turns of the bead may be in tangential contact with the rotary roller.

The cord can be guided towards the winding drum by a central face of a finger, engaged in the support or belonging to the support.

• La figure 1 représente un mode de réalisation d'un enrouleur de cordon selon l'invention, en vue isométrique.
• La figure 2 représente une vue éclatée partielle et isométrique de ce mode de réalisation d'enrouleur à cordon.
• La figure 3 représente une vue assemblée des éléments de la figure 2.
• La figure 4 représente une vue de profil des éléments de la figure 2, avec assemblage partiel des éléments.
• La figure 5 représente une vue isométrique d'un palier du mode de réalisation d'enrouleur à cordon.
• La figure 6 représente une vue intérieure d'un palier.
• La figure 7 représente une variante de réalisation d'un moyen de guidage d'entrée du cordon utilisé dans le mode de réalisation d'enrouleur de cordon selon l'invention.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings in which:

• The figure 1 represents an embodiment of a cord winder according to the invention, in isometric view.
• The figure 2 is an exploded partial and isometric view of this cord winder embodiment.
• The figure 3 represents an assembled view of the elements of the figure 2 .
• The figure 4 represents a profile view of the elements of the figure 2 , with partial assembly of the elements.
• The figure 5 is an isometric view of a bearing of the cord winder embodiment.
• The figure 6 represents an interior view of a landing.
• The figure 7 represents an alternative embodiment of a cord input guiding means used in the cord winder embodiment of the invention.

The invention significantly improves the prior art window cover cord reels by the use of a rotary roller disposed in direct contact with the first winding turns of the cord.

The figure 1 represents a cord winder 1 according to the invention, in isometric view. As described in the prior art, the cord winder is intended to wind a cord 40 and to be arranged in a box of a cover device of a window, not shown.

It comprises a support 2, forming a first bearing, and a second bearing 3 connected to the support by a cradle 4. The support is fixed on a base 5. A frame 6 is mounted on the support to allow the assembly of several parts on the support. A winding drum 7 is supported by the support and the second bearing and is rotatable about a first axis of rotation AA '. Alternatively, the support also forms the base.

The figure 2 represents a partial exploded view and isometric view of the corded winder, and the figure 3 represents an assembled view of the elements of the figure 2 .

The winding drum comprises a first ring 8 and a second ring 9, coaxial with the first axis of rotation and engaged respectively in the first bearing and in the second bearing. These rings are smooth externally so as to rotate in the bearings, and are recessed in a polygonal bore 10 adapted to allow the engagement of a drive shaft 20 to transmit a rotational movement to the winding drum. The drive shaft has for example a hexagonal profile.

Alternatively, the bearings are not necessary. For example the second bearing is not necessary because the centering of the winding drum on the first axis of rotation can be provided by the drive shaft.

In the same way, the support may not form a first bearing when the centering of the winding drum on the first axis of rotation is ensured by the drive shaft, provided that the support is positioned accurately with respect to the drum winding.

The winding drum comprises a means 11 for attaching a bead to the winding drum, for example in the form of a hole enabling the locking of a knot formed on the bead once it has engaged in the hole . Alternatively, the bead attachment means is axially movable along the winding drum, while being locked in rotation relative thereto.

A guiding means 12 for entering the cord into the reel, for example an arrival hole of the cord guiding the cord towards the winding drum, is arranged on the base 5, in the vicinity of a finger 13. The finger 13 may comprise a first thrust means 13a of the cord, as described below. Alternatively, the first thrust means may comprise a shoulder, made on one end of the winding drum.

The guiding means may comprise a small pulley or alternatively two rollers of moving and substantially perpendicular axes, to guide the entry of the cord into the cord winder while limiting friction.

A rotary roller 14, rotatable about a second axis of rotation BB 'substantially parallel to the first axis of rotation, is disposed in the support in the vicinity of the winding drum, the guide means, and the first thrust means, as specified later.

This rotary roller is mounted by fitting on a secondary shaft 15, having a first shaft end 15a and a second shaft end 15b of the secondary shaft. Alternatively, the rotary roller may be extended by axial pins forming the first shaft end and the second shaft end. The role of the rotary roller is to apply friction on the cord. A pressure means 16, preferably of elastic type, is such that the rotary roller applies pressure to one or more turns of the cord wound on the winding drum.

By this is meant that one or more bead turns are both in circumferential contact with the winding drum and in tangential contact with the rotary roller, the tangential contact being of pressing type and causing friction on the bead.

For example, the pressure means exerts a thrust on the rotary roller so that it is returned to the winding drum in contact with the coiled turns of the cord. Thus, a first elastic element 16a (such as a steel strip) and a second elastic element 16b respectively bear elastically on the first end and the second end of the secondary shaft. The two elastic elements constitute the elastic pressure means 16 allowing the rotary roller to frictionally drive turns wound on the winding drum.

A first pinion 17 is integral in rotation with the secondary shaft, while a second pinion 18 is integral in rotation with the drum. winding. The second pinion is for example mounted on a drum surface provided with a flat 19, preferably engaged in force on the scope of the drum provided with the flat 19. The first pinion meshes with the second pinion. The role of the gears is described below.

An orientation means 21 of the cord is for example constituted by a cylindrical pin whose axis of the cylinder is oriented in a direction at least substantially radial to the winding drum. The orientation means is fixed on the support. The radial distance between the orienting means and the winding drum is much smaller than the diameter of the bead. This orientation means can be rotatably mounted around the radial direction. The role of the orientation means is described below.

The figure 4 represents a profile view of the elements of the figure 2 , with partial assembly of the elements and schematic representation of the cord 40 wound on several turns and a reference 22 diagrammatically dotted line a path in the winder.

The term "first turn" means a first bead turn in contact with the winding drum when moving on the bead from the guide means 12 to enter the cord into the winder.

• une première zone, dite zone d'enroulement 7a, située au voisinage du support, comprenant au moins la première spire et comprenant une zone de friction 23 dans laquelle plusieurs spires du cordon sont en contact à la fois avec le tambour d'enroulement et avec le galet rotatif. Puis, en s'éloignant du support :
• une deuxième zone, dite zone intermédiaire 7b et/ou 7b', dans laquelle a lieu une diminution du diamètre du tambour d'enroulement. Puis, en s'éloignant du support :
• une troisième zone, dite zone de stockage 7c, présentant un diamètre inférieur à celui de la zone d'enroulement, au moins au niveau de son raccordement avec la zone intermédiaire.

In this profile view, it clearly appears that the winding drum comprises at least:

• a first zone, referred to as the winding zone 7a, situated in the vicinity of the support, comprising at least the first turn and comprising a friction zone 23 in which several turns of the bead are in contact with both the winding drum and with the rotary roller. Then, moving away from the support:
• a second zone, called intermediate zone 7b and / or 7b ', in which there is a decrease in the diameter of the winding drum. Then, moving away from the support:
• a third zone, called storage zone 7c, having a diameter smaller than that of the winding zone, at least at its connection with the intermediate zone.

The winding zone 7a is therefore a winding drum portion comprising a first turn of the bead and including the friction zone 23 in which at least one turn of the bead is both in circumferential contact with the winding drum and in tangential contact with the rotary roller. The winding zone may have an axial length greater than the axial extension of the friction zone, as on the figure 4 .

The winding zone preferably has a constant diameter. In this case, the secondary shaft and the rotary roller have a second axis of rotation B-B 'parallel to the first axis of rotation A-A'. Alternatively, the winding zone may have a regular and weak decrease in diameter (a few hundredths of a millimeter per millimeter) when approaching the intermediate zone. This slightly conical geometry may be favorable for a demolding operation. It can also help to promote the capstan effect.

The winding drum may not include discontinuity of shape, for example be formed of a piece of conical revolution, whose diameter decreases regularly when moving away from the guide means. In this case, the winding zone extends over the entire axial length of the winding drum.

In the case of a conical profile of the winding area, the second axis of rotation is taken parallel to the side of the cone. The second axis of rotation therefore remains substantially parallel to a generatrix of the winding zone, this generatrix being able to be parallel to the first axis of rotation (cylindrical winding zone) or to be slightly inclined with respect to this axis (zone of rotation). conical winding).

Preferably, the winding drum is smooth, so as to have a coefficient of friction as low as possible, especially in the axial direction.

The friction of the rotary roller on the bead results from the action of the pressure means. The resilient blades exert a force on the secondary shaft so as to push the rotary roller toward the winding drum and to rub on the turns in the friction zone. Alternatively, the secondary shaft is fixed, and the pressure roller comprises an elastically deformable coating capable of exerting elastic pressure on the cord and then constituting the elastic pressure means.

Preferably, there is a combination of the elastic blades and the elastically deformable coating, for example elastomer, to form the pressure means.

According to an alternative embodiment, the friction of the rotary roller on the bead results from the action of gravity, the rotary roller then being made of a material of high density. A friction coating, or a surface treatment, can also make sufficient friction of the roller on the cord, without the need to use an elastic-type pressure means. The radial elasticity of the cord can also be used to avoid the need for an elastic-type pressure means.

The orientation means 21 is arranged on the support, at the exit of the winding zone. It ensures a good exit of the cord to the storage area in the case of a winding, and conversely it ensures a good entry of the cord into the winding area in the case of unwinding.

Upon entering the cord winder, the cord is thrust axially towards the storage area by a side surface of the finger 13 constituting the first thrust means 13a. Thus, if the turns are contiguous, a new turn tends to push the coils already wound in the direction of the storage area.

Conversely, during unwinding, the friction of the rotary roller on the cord makes it possible to push the last coil wound towards the guide means 12, thus to push the cord out of the cord winder, which solves the problem. of the prior art.

However, the operation is greatly improved by the introduction of a means for controlling the rotation of the rotary roller to that of the winding drum. This servo means comprises the first and second gears already described. If the gear ratio is substantially equal to the ratio of the respective diameters of the winding drum and the rotary roller, then these two elements have substantially the same tangential speed, which speed is communicated to the cord to remove it from the cord winder , or get it into the cord winder, even in the absence of tension on the cord.

In the case of a winding zone where the diameter of the drum is changing (conical zone), the roller may also be conical so that the speeds tangential of the drum and the roller are the same in any cross section of the winding zone where the roller is located. The second axis of rotation is then more inclined than the generatrix of the winding zone, with respect to the first axis of rotation.

The winding drum is capable of taking many forms, provided that it comprises a friction zone as defined above.

For example, the storage area 7c may have a conical profile of slightly increasing diameter as one moves away from the guide means. Indeed, if the attachment means of the cord is fixed, then the turns see their diameter increase when they are pushed towards the attachment means.

Moreover, the operation is greatly improved by the use of a second thrust means, described below.

The figure 5 represents an isometric view of the support 2.

On the upper part of the support, a housing 24 makes it possible to house the rotary roller. A first straight groove 25a and a second straight groove 25b serve as respective guides for the first shaft end 15a and the second shaft end 15b of the secondary shaft. An upper plate 26 receives the frame 6 allowing the final assembly of the secondary shaft and the elastic blades in the support.

A circular hole 27 is intended to receive the first ring 8 of the rotary drum, so as to perform the bearing function. A recess 28 accommodates the first and second gears. A radial hole is provided to accommodate the pin serving as an orientation means 21.

The support also comprises a cylindrical bore 33 comprising a helical groove 31, interrupted at the housing 24.

The figure 6 represents an interior view of the support. The cylindrical bore 33 has a diameter greater than the diameter of the winding zone. Thus, the winding zone penetrates inside the support.

In addition, a machining of the support or other technical means allows the realization of the helical groove, in which circulates the cord. This helical groove is delimited by a helical wall 30. Four sections 30a-30d of the helical wall appear at the housing 24, which interrupts the helical wall.

Also appear in figure 5 several sections 30a, 30b of the helical wall, resulting from this interruption of the helical wall by the housing 24.

Unlike the prior art, the turns of the cord are no longer joined in this case. The helical wall thus serves as a second means of thrusting the turns towards the storage area in the case of a winding.

Conversely, the helical wall also serves as a means of thrusting the turns towards the guide means during unwinding.

The helical groove has a depth greater than the radius of the cord. The interruption of the helical wall at the housing 24 can be only partial, the wall being continuous in its smallest diameter and only interrupted in its larger diameter so as to allow the pressing action of the rotary roller on the cord.

The helical wall is preferably formed around the drum only at the level of the friction zone.

Preferably, the helical wall is only partially interrupted at the housing, and forms an integral piece integral inserted in the bore 33, for example by screwing. The zone 34 partially represents a tapping formed in the bore 33 of the support. The tapping may have the same pitch as the helical wall, and the latter (which comprises much fewer turns than the thread of the bearing and whose shape of the section is different from that of the thread of the tapping) is implemented by screwing in the thread.

A helical wall termination is identified by reference 32. This termination is located beyond the friction zone. According to the invention, the helical wall may extend axially over the entire length of the winding zone, but it is preferable that it acts on at most one turn outside the friction zone. The termination is located, heading towards the storage area, within one turn of the last turn of the friction zone: for example three quarters of a turn on the figure 6 .

From this termination, the orientation means is itself located less than half a turn of the termination, so as to allow the cord orientation actions described above.

This orientation means is therefore disposed within two turns of the last turn of the friction zone, preferably less than 1.5 turns.

On the figure 6 a notch 35 is formed allowing the first thrust means 13 to pass, as well as a hole 36 placed opposite the guiding means 12 and leaving the passage to the bead.

The figure 7 represents in a partial view similar to that of the figure 4 an alternative embodiment of the cord input guiding means.

In this preferred embodiment, the finger 13 completes the guide means 12 formed by the arrival hole of the cord in the base 5. The cord is guided by a central face 13b of the finger. The profile of this central face 13b is such that it provides a space between the winding drum and the central face 13b of width slightly greater than the diameter of the cord. Thus, the rounded profile of the central face of the finger facilitates the insertion movement of the cord on the winding drum and minimizes friction in the vicinity of the arrival hole of the cord. Advantageously, the central face of the finger can be shaped as a gutter. Alternatively, the central face 13b can be integrated into the support so that it understands itself this function of guiding the cord.

The cord thus enters the reel in a plane perpendicular to the axis of rotation of the drum until reaching an upper end 13c of the finger 13. At this point, the cord penetrates into the helical groove, as indicated by a reference 22b .

When this variant is used, the cord winder comprises only one thrust means, namely the second thrust means. Whatever the means of thrust used, the behavior of the cord is such that it does not slip angularly on the winding drum in the winding zone, while it slides axially.

The winding angle of the cord on the drum between the point of application of the rotary roller on the first turn of the cord and the first point of contact of the first turn to the drum is less than 180 ° in the case of the figure 4 , and preferably less than 60 °, typically 45 °, in the case of the figure 7 .

The construction of the cord winder according to the invention therefore deviates from the devices of the prior art to have the considerable advantage of allowing the thrust of the cord outside the winder even in the absence of load on the cord, during an unwinding maneuver. While the reels of the prior art generally have at most one turn wound on the winding drum, in a fully unwound position of the cord, the winder according to the invention is such that the number of turns of the zone of friction is independent of the winding or unwinding state of the bead, which implies that in fully unrolled position there remains at least this minimum number of turns wound on the winding drum. The figure 4 22a represents the position of the cord in the storage zone, in a fully unwound position: the configuration of the cord between the guide means and the orientation means is, on the other hand, identical, that the winding drum is totally curled or fully unwound.

In addition, the cord winder according to the invention also has the advantage of allowing a regular winding of the cord in the winder even in the absence of load on the cord. This feature is particularly useful in the case of window having a very low mass, or in the case where an involuntary movement of the user would relieve the load bar during a winding phase. It also makes it possible to reduce the mass of the load bar.

Claims (15)

1. A cord winder (1) for a window covering device, comprising a drum (7) for winding a cord (40) adapted to be driven in rotation about a first revolution axis (A-A'), an element (12, 13b) for guiding the cord toward the winding drum, the winding drum being mounted to be mobile in rotation in a support (2), characterized in that it comprises a rotary roller (14) mounted on the support to rotate about a second revolution axis (B-B') and in that it comprises a friction area (23) in which at least one turn of the cord wound on the winding drum is in contact with the rotary roller.
2. The cord winder claimed in claim 1, characterized in that the rotation of the rotary roller is slaved to the rotation of the winding drum by a slaving element (17, 18).
3. A cord winder as claimed in either one of the preceding claims, characterized in that the slaving element comprise a first pinion (18) constrained to rotate with the winding drum and meshing with a second pinion (17) constrained to rotate with the rotary roller.
4. A cord winder as claimed in any one of the preceding claims, characterized in that, in the friction area (23), the rotary roller applies pressure to at least a first turn of the cord wound onto the winding drum, for example the first turn and another turn or the first turn and two other turns.
5. A cord winder as claimed in claim 4, characterized in that it comprises an element (21) for orienting the cord fastened to the support and disposed in the vicinity of the friction area in the direction away from the guide element and at least two turns of cord of a final turn in contact with the rotary roller.
6. A cord winder as claimed in either one of claims 4 or 5, characterized in that the number of turns in the friction area is independent of the state of winding or of unwinding of the cord.
7. A cord winder as claimed in any one of the preceding claims, characterized in that a pushing element (13a, 30) act at least on the turns in contact with the rotary roller to move them away from the guide element.
8. A cord winder as claimed in claim 7, characterized in that the pushing element comprise a helical wall (30).
9. A cord winder as claimed in claim 8, characterized in that the helical wall (30) is formed in a cylindrical bore (33) of the support, said cylindrical bore containing at least the friction area, and in that the helical wall is at least partially interrupted by a housing (24) of the rotary roller.
10. A cord winder as claimed in any one of the preceding claims, characterized in that the rotary roller comprises two shaft ends (15a, 15b) belonging for example to a secondary shaft (15) and guided in the support, notably by two straight grooves (25a, 25b) provided in the support.
11. A cord winder as claimed in any one of the preceding claims, characterized in that a pressing element (16) push the rotary roller toward the drum.
12. A cord winder as claimed in claim 11, characterized in that the pressing element comprise an elastic element (16a, 16b) of the support in contact with a shaft end of the rotary roller.
13. A cord winder according to any one of the preceding claims, characterized in that the rotary roller comprises an elastomer coating and/or a friction coating.
14. A cord winder as claimed in any one of the preceding claims, characterized in that at most five consecutive turns of the cord are in tangential contact with the rotary roller.
15. A cord winder as claimed in any one of the preceding claims, characterized in that the cord is guided toward the winding drum by a central face (13b) of a finger (13) engaged in the support or belonging to the support.

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