EP2899329A1

EP2899329A1 - Automatic tensioning system for roll-type awnings

Info

Publication number: EP2899329A1
Application number: EP14199998.7A
Authority: EP
Inventors: Renato De Pazzi; Paolo De Pazzi; Damiano Guzzo
Original assignee: Master SpA
Current assignee: Master SpA
Priority date: 2014-01-28
Filing date: 2014-12-23
Publication date: 2015-07-29

Abstract

The present invention relates to an automatic tensioning system (100) adapted to cooperate with an awning sheet of a motor-driven roll-type awning comprising a first electric motor (11) comprising a rotating shaft integral with a winding roll-bar (1) and a motor head (11A), a second electric motor (12) associated with a tensioning roll-bar (2), said awning sheet (3) being secured with a first edge portion to said winding roll-bar (1) and operatively associable with the edge portion opposite to said tensioning roll-bar (2), said awning sheet (3) being movable between a retracted position wherein it is completely wound about said winding roll-bar (1) and an extended position, wherein it is at least partially unrolled from said winding roll-bar (1), control means (20) connected to said first and said second electric motor (11, 12) to control the movement of the sheet (3). In particular, said system (100) comprises a support bracket (7) whereon said motor head (11A) of said first electric motor (11) is rotatably mountable, elastic means (9) secured to said support bracket (7) and operatively connectable to said motor head (11 A) for biasing its rotation, position detecting means (25), comprising at least a detecting element, adapted to be integrally associated with said motor head (11A), and reference means (50) arranged integral with said support bracket (7) and operatively connectable to said control means (20). Said reference means (50) are adapted to cooperate with said position detecting means (25) for generating a signal when, due to a change of the tensioning condition of the awning sheet (3) with respect to a pre-set tensioning condition, the couple applied on said motor head (11 A) causes its oscillation, said control means (20) being adapted to receive the generated signal and modify or block the movement of the rotating shaft of said first electric motor (11) or said second electric motor (12) in response to the received signal so that the pre-set tensioning condition of the awning sheet (3) is restored. Moreover, the present invention is related to a method for maintaining or restoring a pre-set tensioning condition of an awning sheet of a roll-type awning.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an automatic tensioning system or mechanism for roll-type awnings, in particular driven by a couple of electric motors. Moreover, the present invention relates to a method for maintaining or restoring a pre-set tensioning condition of an awning sheet.
Motor driven awnings have been known for a long time and widely appreciated for their practicality and their convenience; as schematically shown in the appended figures 1 and 2, they generally comprise a pair of parallel roll-bars, rotatably mountable on a fixed support structure, such as a frame or a wall, each one driven by a corresponding electric motor 11, 12, advantageously of the tubular type so as to be, at least partially, inside the respective roll-bar.
Further, the awning comprises a fabric or plastic sheet 3 secured with an edge portion to a first one of said roll-bars, named "winding roll-bar" 1, whereon the sheet 3 is wound up and from where it is unrolled when operating the awning, whereas the opposite edge portion of the sheet is operatively associable to the other roll-bar, named "tensioning roll-bar" 2, having the function of accompanying the unrolling and winding up of the sheet while operating the same awning and whereon the sheet is not wound up; the sheet 3 is movable between a retracted position, wherein it is completely wound about said winding roll-bar 1 and a completely extended position, wherein it is completely unrolled from said winding roll-bar 1. Of course, the sheet 3 can also permanently take and keep a plurality of intermediate positions between said retracted position and said extended position, wherein it is at least partially unrolled from said winding roll-bar 1.
The tensioning roll-bar 2 can be mounted on the fixed structure in correspondence with the completely extended position of the awning, and in this case the sheet will be secured to said roll-bar 2 by means of dragging belts, as schematically shown in figure 1. While operating the awning, the electric motors associated with the two roll-bars are set in motion at the same time and the sheet, initially wound about the winding roll-bar, is progressively unrolled from it until it reaches the desired unrolled position.
Alternatively, as schematically shown in figure 2, said tensioning roll-bar 2 is mounted in the proximity of the winding roll-bar 1; in this case, the sheet is secured with a first edge portion to the winding roll-bar 1, while the opposite edge portion is associated with a sliding traverse 4, slidable in the awning winding/unrolling direction thanks to a pair of sliding elements mounted on its ends; said sliding elements are associated to a pair of transmission belts 5 activated by the motor of the tensioning roll-bar 5 and ring closed between said tensioning roll-bar 2 and an idler countershaft 6 placed in correspondence of the awning complete extended position.
Also in this case, when operating the awning both motors are set in motion at the same time: the tensioning roll-bar 2 causes the transmission belts 5 to move, which in turn drag the sliding traverse 4 whereto the sheet 3 is secured; at first, this one is wound about the winding roll-bar 1, then it is progressively unrolled thanks to the combined action of the sliding traverse 4 and of the rotating movement of the winding roll-bar 1 by means of the respective electric motor.
An inconvenience which typically occurs in the above described motor-driven roll-type awnings derives from the fact that, during its operation, the sheet is not under a constant tension, but at times it has an excessive tensioning, when the dragging speed imposed by the traverse is higher than the unrolling/winding speed given by the winding roll-bar, and at times the tensioning is insufficient because the unrolling/winding speed is higher than the dragging speed. Besides being particularly unattractive, this is above all detrimental for the sheet which would be prematurely worn out.
Such inconvenience is caused by the fact that, the rotation frequency imposed to the rolls by the corresponding electric motors being the same, while the dragging speed V2 given by the movement of the movement belts to the traverse is basically constant during all the moving phases of the awning, the unrolling/winding speed V1 of the sheet from the winding roll-bar varies depending on the overall diameter defined by the winding roll-bar diameter to which it is added a variable quantity formed by the sheet temporarily wound about it.
Clearly, the overall diameter varies between a maximum value in the retracted position, that is when the sheet is completely wound about the winding roll-bar, and a minimum value reached when the sheet is completely unrolled from the winding roll-bar and consequently the overall diameter basically coincides with the diameter of the same winding roll-bar.
In conclusion, because of this variable difference of the speeds V1 and V2 the tensioning condition of the sheet 3 is not constant during the unrolling/winding phases.
The systems on the market at the moment try to solve the above said problem by means of a merely electronic management of the two motors: in particular, while unrolling the sheet, the motor, which controls the winding roll-bar, works as an engine braking, while when winding the sheet up, it is the tensioning roll-bar to work as an engine braking.
In this way, while being unrolled, the sheet is dragged from the side of the traverse thanks to the tensioning roll-bar motor and at the same time braked by the winding roll-bar motor, thus being tensioned.
When the awning ends its movement, for example because the sheet has been completely extended or the user wants it at an intermediate position, the feed of the motor connected to tensioning roll-bar is stopped, while the motor associated with the tensioning roll-bar reverses the rotating direction kept till then so that the sheet will be tensioned.
However, the braking value and the time during which the motor of the winding roll-bar reverses its direction are two pre-set parameters set when installing the awning; hence at that moment it is necessary to identify a balanced functioning which can ensure an acceptable tensioning of the sheet in the various conditions occurring during the winding/unrolling travel of the sheet, very often an operation which is far from banal and not always accurate.
Further, such system operates "rigidly" and therefore it is not capable of compensating automatically and autonomously sudden changes of the sheet tensioning due to external causes, such as a gust of wind or thermal expansion to which the sheet is subject. Moreover, it is worthwhile to underline that such operation is not optimal for the electric motors because in order to be able to work as engine braking, both the coils have to be fed simultaneously; for this reason, in the long run, motors risk damaging.
In conclusion, the systems on the market at the moment solve the problem of the sheet tensioning only partially.

SUMMARY OF THE INVENTION

The main object of the present invention is that of overcoming the inconveniences of the known technique devising an automatic tensioning system for a motor-driven roll-type awning capable of automatically maintaining or restoring the sheet tensioning during the winding/unrolling phases of the awning.
In the field of the above said object, an important aim is that of devising a tensioning system for a motor-driven roll-type awning capable of automatically balancing out possible tensioning changes of the awning sheet due to external causes.
Further aim of the present invention is that of obtaining a tensioning system which can be applied to any kind of motor-driven roll-type awnings, without any need for modifying its structure or the working of its motors.
Further purpose of the present invention is that of obtaining a tensioning system formed with simple components, easy to realize and to install on an awning.
Not the last aim of the present invention is that of providing a tensioning system for a roll-type awning achievable using the usual and known plants, machineries and equipment.
The above-mentioned object, aims and advantages as well as others which will become more apparent in the following description, are achieved by means of a tensioning system of the sheet of a roll-type awning as defined in claim 1 and of a method as defined in claim 10.

BRIEF DESCRIPTION OF FIGURES

Advantages and advantageous characteristics of an automatic tensioning system of a sheet for a roll-type awning according to the present invention will be better described in the description of particular, but not excluding, embodiments shown for exemplification only but not limited to, in the appended drawings wherein:

figures 1 and 2 are perspective views schematically showing two kinds of motor-driven roll-type awnings according to the known art;
figure 3 shows a plan view of a roll-type awning to which it is associated an automatic tensioning system according to the present invention;
figures 4A and 4B show, schematically and according to side and top views, an automatic tensioning system according to the present invention;
figure 5 shows how a tensioning system according to the present invention operates when the sheet is in a stationary phase;
figures 6 and 7 show how a tensioning system according to the present invention operates when the sheet unrolling speed is higher than the dragging one;
figure 8 shows how a tensioning system according to the present invention operates when the sheet is in a stationary position in case of excessive load.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

With reference to the previous figures, in particular to figure 3, there is shown a particularly advantageous embodiment of a motor-driven roll-type awning to which an automatic tensioning system of the sheet 100 is associated according to the present invention.
In the description which follows there can be used terms such as "on", "under", "upper", "lower", "high", "low" or the like; the skilled in the field will not have any difficulties in understanding that such terms are referred to a tensioning system in its usual working condition, that is operating, as shown in the appended figures.
A motor-driven roll-type awning preferably comprises a first roll-bar 1 or winding roll-bar, and a second roll-bar 2, or tensioning roll-bar, rotatably mountable parallel one to the other on a support structure 10, such as a frame or a wall, each of said roll- bars 1, 2 preferably being formed of a hollow cylindrical body extending along an axis X.
A first and second electric motor 11, 12 are operatively connected respectively with said winding roll-bar 1 and with said tensioning roll-bar 2; advantageously, said motors 11 12 are of the tubular type and each comprises a rotating shaft adapted to be housed inside the corresponding roll-bar in order to give it the rotating movement, and a head 11 A, 12A advantageously arranged outside the respective roll-bar.
The roll-type awning further comprises a sheet 3, preferably made of fabric or plastic material, securable with a first edge portion to said winding roll-bar 1, whereon the sheet 3 is wound and from where it is unrolled while operating the awning, and with a second edge portion, opposite to said first edge portion, operatively associable to said tensioning roll-bar 2, having the function of accompanying the winding and unrolling of the sheet while operating it and whereon the sheet 3 is not wound .
For example, as shown in figure 3, said second edge portion of the sheet 3 can be secured to a traverse 4, slidably movable along side guides by means of a pair of movement belts 5 to which the ends of the traverse 4 are associated, ring closed between a countershaft 6 and said tensioning roll-bar 2, said movement belt 5 being operated by said second electric motor 12.
Said sheet 3 can be moved through the combined action of said first and said second electric motor 11, 12 between a winding position, wherein it is basically completely wound about said winding roll-bar 1, and a position of maximum extension, wherein it is completely unrolled from said winding roll-bar 1. Of course, the sheet 3 can permanently take and keep a plurality of intermediate positions between said retracted position and said extended position, wherein it is at least partially unrolled from said winding roll-bar 1.
Control means 20, such as a suitably programmed electronic board, are connected to said first and said second electric motor 11, 12 to activate the corresponding rotating shafts in response to a command sent, for example, by the user via a remote control.
Even if the rotation frequency imposed to said winding roll-bar 1 and to said tensioning roll-bar 2 by the corresponding electric motors 11, 12 is the same, the winding/unrolling speed V1 of the sheet from the winding roll-bar 1 is not always the same as the dragging speed V2 with which the traverse 4 translates.
In fact, while the dragging speed V2 imposed to the traverse 4 by the movement of the movement belts 5 is basically constant during all the movement phases of the awning, the unrolling/winding speed V1 of the sheet 3 from the winding roll-bar 1 varies as it basically depends on (in particular directly proportional) the overall diameter defined by the diameter of the winding roll-bar 1 to which it is added the diameter of the sheet wound about it.
Clearly, the overall diameter varies between a maximum value in the retracted position when the sheet 3 is completely wound about the winding roll-bar 1, and a minimum value when the sheet 3 is completely unrolled from the winding roll-bar 1 and consequently the overall diameter basically coincides with the diameter of the same winding roll-bar 1. Thus, because of this variable difference of the above described speeds V1 and V2, the tensioning condition of the sheet 3 is not constant during the unrolling/winding phases.
A tensioning system 100 according to the present invention is advantageously associable to a motor-driven roll-type awning according to the foregoing in order to detect, at any time, the tensioning condition of the sheet 3 based on the difference between the two speeds V1 and V2, and modulate, in response to the detected information, the operation of the first motor 11 connected to the winding roll-bar 1 or of the second motor 12 connected to the traverse 4, so as to maintain or restore a pre-set tensioning condition of the sheet 3. In other words, thanks to the action of said automatic tensioning system 100, the operation of the roll-type awning is based on the tensioning condition of the sheet 3.
In order to do so, the head 11 A of the first motor 11 connected to the winding roll-bar 1 is advantageously mounted idle with respect to the support structure 10, allowing a further degree of freedom, thanks to which it is possible to detect the oscillations of the head 11 A of the motor 11 caused by the difference between speeds V1 and V2 and therefore by the change of the tensioning condition of the sheet 3.
As shown in figures 4A and 4B, a tensioning system 100 according to the present invention comprises a support bracket 7 rigidly associable to the support structure 10 of the awning and adapted to rotatably support the head 11 A of said first motor 11, preferably through a flange 8.
The tensioning system 100 further comprises elastic means 9, associable to said support bracket 7 and operatively connectable to said head 11 A for biasing its rotation, position detecting means 25 integrally mountable to said head 11 A and reference means 50 arranged on said support bracket 7 so as to cooperate with said position detecting means 25 in order to detect the oscillations of the head 11 A.
Further, said reference means 50 are advantageously connectable with the electronic board 20 of said roll-type awning so as to suitably modify the operation of said electric motors 11, 12, as later explained with greater detail.
Said flange 8 is preferably constituted of a coupling portion 8A through which it is rigidly connectable the head 11 A, a transmission hub 8B extending along the same rotation axis X of the winding roll-bar and rotatably mounted on said support bracket 7, and a transfer portion 8C, preferably round shaped, having the rotation centre C basically coinciding with the passage point of the axis X and integrally rotatable with said head 11 A.
The rotation of the flange 8, and hence of the head 11 A, on the support bracket 7 is idle and it occurs in contrast with said elastic means 9, such as at least a spring, having a first end 9A secured to said support bracket 7 and the opposite end 9B connected to said transfer portion 8C of the flange 8, advantageously in correspondence with a portion of a perimeter edge of the same.
Said position detecting means 25 advantageously comprise at least one position detecting element arranged on the transfer portion 8C of the flange 8 in correspondence with an edge portion of the same basically arranged diametrically opposed with respect to the portion to which the second end 9B of the spring 9 is secured.
Said position detecting element 25 is adapted to cooperate with said reference means 50 arranged on the bracket 7 to generate electric signals to be transmitted to the electronic board 20 in the occurrence of situations when the tensioning condition of the sheet 3 is modified of a certain extent with respect to the pre-set one; afterwards, the electronic board 20 suitably modifies the operation of the two electric motors 11, 12 in order to restore the tensioning condition of the sheet 3 to the desired level.
The cooperation between said position detecting element 25 and said reference means 50 can be of mechanical type, and therefore said position detecting element 25 is formed by, for example, a pin protruding with respect to the circumference edge of said transfer portion 8C of the flange 8, and said reference means 50 comprise corresponding elements against which the pin comes into contact, in order to signal the oscillation of the head 11 A.
Alternatively, as shown in the appended figures, the cooperation between the position detecting element 25 and the reference means 50 is of the magnetic kind; in this case, advantageously, said position detecting element 25 is formed of a magnet and said reference means 50 comprise sensors, such as micro-switches, responsive to the close passage of said magnet 25, to signal the oscillation of the head 11 A.
Said reference means 50 comprise at least a first sensor 27, arranged on the bracket 7 so as to define the desired tensioning level of the sheet 3, which will then coincide with the pre-set tensioning condition.
The operating principle of the tensioning system 100 according to the present invention is based on the equilibrium of torques acting on the flange 8: on one side there is the couple due to the force acting on the sheet 3, whose change is caused by the difference of the speeds V1 and V2, which causes oscillations of the head 11 A of the first motor 11, on the other side there will be a couple due to the elastic means 9 biasing the force changes acting on the sheet 3. The pre-set tensioning condition of the sheet 3 is then set by choosing an elastic means 9 having a suitable elastic constant.
As for the couple acting on the flange 8, it tends to rotate in order to reach a condition of equilibrium, dragging into rotation the position detecting element 25, which distances itself from or gets near to said first reference sensor 27 depending on the tensioning condition acting on the sheet 3.
In particular, during the unrolling of the sheet 3 from the winding roll-bar 1 both motors 11, 12 are activated simultaneously and jointly, for example, thanks to a signal sent by the user who wants to unroll the awning.
Therefore there can occur four possible conditions:

a) the unrolling speed V1 of the sheet 3 is higher than the dragging speed V2 and hence the tensioning condition of the sheet decreases with respect to the pre-set tensioning condition;
b) the unrolling speed V1 of the sheet 3 is basically the same as the dragging speed V2 (this ideal condition occurs for only a few seconds, and the system 100 is not activated);
c) the unrolling speed V1 of the sheet 3 is lower than the dragging speed V2 and therefore the tensioning condition of the sheet increases with respect to the pre-set tensioning condition;
d) the sheet 3 is in a stationary position, for example it has reached the position of maximum expansion or the user has sent a stop signal at an intermediate unrolling position of the sheet 3.

In the stationary condition (condition d), the sheet 3 has the pre-set tensioning level; in this condition, in fact, the position detecting element 25 is arranged in correspondence of said first sensor 27, while the elastic element 9 keeps the value of the sheet tensioning at the pre-set optimal level.
In condition a), the tensioning condition of the sheet 3 starts decreasing with respect to the pre-set condition. In this condition, to have the equilibrium of torques resting on the flange 8, this one rotates in the reverse direction with respect to the rotating direction of the winding roll-bar 1 under the action of the force from the elastic means 9, then rotatably moving from the position of the starting equilibrium. The position detecting element 25, integral to the head 8C of the flange 8, follows the rotation of this one, distancing itself with respect to said first reference sensor 27 arranged on the support bracket 7.
The moving away of the position detecting element 25 from the first reference sensor 27 causes their cooperation to stop and the resulting generation of a signal which is sent to the electronic board 20. As the position of said first reference sensor 27 is such as to define the pre-set tensioning level of the sheet 3, the signal sent to the electronic board 20 is understood as a decrease of the tensioning of the sheet 3.
After a certain time interval from the signal transmission, suitably pre-set so as the tensioning of the sheet does not go over a minimum level, the electronic board 20 temporarily stops the feed of said first electric motor 11, so that the sheet is subject only to the traction of the traverse 4, progressively increasing its tensioning condition.
In fact, because of the stop of said first motor 11, the flange 8 is caused to rotate in the unrolling direction of the sheet 3, consequently dragging the position detecting element 25 into rotation until it positions itself again in the proximity of said first sensor 27, generating a new signal to be sent to the electronic board 20 in response to which the first electric motor 11 resumes its normal operation.
Advantageously, as an alternative to the timed management of the operation of the first motor 11, it is possible to provide a second reference sensor 26, arranged on the bracket 7 so as to precisely define the minimum tensioning level of the sheet 3 and generate a signal at the close passage of said position detecting element 25.
Therefore, in the previously described situation, in response to the slackening of the tensioning condition of the sheet 3, the position detecting element 25 rotatably distances itself from the first sensor 27, coming in the proximity of the second sensor 26; hence it is generated a signal soon sent to the electronic board 20 which interrupts the feed of the first motor 11.
Vice versa, when the dragging speed V2 of the sheet 3 is higher than the unrolling speed V1 of the sheet 3 from the winding roll-bar (condition c), the electronic board 20, depending on the signals sent by the sensors 26, 27, will stop the second motor 12 which moves the traverse 4, maintaining the first motor 11 operational until the pre-set tensioning is resumed.
Of course, said first and said second reference sensors 26, 27 are arranged so that the tensioning changes of the sheet with respect to the pre-set condition, are minimal, that is, the minimum tensioning level of the sheet is not a tensioning level which causes creases in the same sheet, and the maximum tensioning level does not cause any stress to the material the sheet is made of.
Therefore, during all the unrolling/winding phases of the sheet 3, wherein the above said conditions occur, the tensioning system 100 suitably activates and stops the two electric motors 11, 12, imposing an "accordion-like" operation, but wherein the changes of the tensioning condition of the sheet 3 are very limited, basically imperceptible.
When the sheet 3 stops, for example because it has been reached the end of its travel or because the user blocks it at an intermediate position, the electronic board 20 suitably acts on the motors, stopping one of them and reversing the rotation direction of the other so that the sheet is brought to the pre-set tensioning condition. The rotation ends when the position detecting element 25 cooperates again with said first sensor 27.
Possibly, the tensioning system 100 can be further implemented providing a third reference sensor 28, arranged on said support bracket 7 so that said first sensor 27 is placed between said second sensor 26 and said third sensor 28, to detect possible changes of load insisting on the sheet 3 (for ex: snow or gusts of wind) when it is in stationary conditions, increasing the tensioning condition with respect to the pre-set one, and to generate a signal at the close passage of said position detecting element 25.
The electric signal sent by this third sensor 28 will be used in a suitable way by the electronic board 20 to preserve the awning integrity. In figure 8 it is shown how the tensioning system 100 works in case of excessive load when the sheet is stationary: at first, the position detecting element 25 engages the first sensor 27. As the load on the sheet 3 increases, for example because of the snow, the flange 8 rotates in the unrolling direction of the sheet 3 and the position detecting element 25 overcomes said first sensor 27, getting close to said third sensor 28. Depending on the electric signal received, the electronic board 20 will act, for example, imposing the winding of the sheet 3 on the winding roll-bar 1 and the consequent closing of the awning.
A tensioning system 100 according to the present invention can be applied without any difficulties to any type of motor-driven roll-type awning, different from the one described and shown as well, as long as it is provided with a sheet and a pair of electric motors.
Moreover, the present invention allows to provide an innovative method for maintaining or restoring a pre-set tensioning condition of an awning sheet of a roll-type awning provided with a pair of roll-bars operated by corresponding electric motors, said method comprising the steps of:

a) detecting any change in the tensioning condition of the awning sheet with respect to a pre-set tensioning condition;
b) generating a signal for a change in the tensioning condition with respect to the pre-set condition greater than a pre-defined entity;
c) modifying or blocking the winding/unrolling speed of the awning sheet to restore the pre-set tensioning condition.

In conclusion, from the foregoing, it is apparent how an automatic tensioning system 100 of a sheet of a motor-driven roll-type awning according to the present invention achieves the objects and advantages stated at the beginning.
In fact, it has been devised an automatic tensioning system 100 adapted to cooperate with a sheet 3 of a motor-driven roll-type awning comprising:

a first electric motor 11 comprising a rotating shaft integral with a winding roll-bar 1 and a motor head 11 A,
a second electric motor 12 associated with a tensioning roll-bar 2,
said awning sheet 3 being secured with a first edge portion to said winding roll-bar 1 and operatively associable with the edge portion opposite to said tensioning roll-bar 2, said sheet 3 being movable about a retracted position, wherein it is completely wound about said winding roll-bar 1, and an extended position, wherein it is at least partially unrolled from said winding roll-bar 1,
control means 20 connected to said first and said second electric motors 11, 12 to control the movement of the sheet 3.

In particular, said system 100 advantageously comprises a support bracket 7 whereon the head 11 A of said first electric motor 11 is rotatably mounted, elastic means 9 secured to said support bracket 7 and operatively connectable to said head 11 A for biasing its rotation, position detecting means 25 comprising at least a detecting element, adapted to be associated integrally with said head 11 A, reference means 50 arranged integral with said support bracket 7 and operatively connectable to said control means 20.
Said reference means 50 are adapted to cooperate with said position detecting means 25 for generating a signal when, due to a change of the tensioning condition of the awning 3 with respect to a pre-set tensioning condition, the couples applied on said motor head 11 A cause its oscillation, said control means 20 being adapted to receive the generated signal and modify or block the movement of the rotating shaft of said first electric motor 11 or said second electric motor 12 in response to the received signal so that the pre-set tensioning condition of the awning sheet 3 is restored.
Practically, a tensioning system of the sheet of a roll-type awning according to the present invention is therefore capable of maintaining or restoring automatically a pre-set tensioning condition while moving and stopping an awning suitably modifying or blocking the movement of the electric motors 11, 12 of the roll-type awning.
The tensioning system according to the present invention works depending on the tensioning resting on the awning sheet to which it is associated, automatically compensating for also tensioning variations due to external causes, without the need for the user's intervention; while moving the awning, therefore the sheet is constantly tensioned in an optimal way.
Hence, thanks to said tensioning system 100, the tensioning resting on the sheet can vary between a desired value and a minimum pre-set value (whose difference is slight), therefore preventing the awning from wearing out.
A tensioning system 100 is easy to install on a motor-driven roll-type awning, in case, also an awning already in use as it is available in a separate kit, and it is immediate to adjust; in fact, it is sufficient to choose an elastic means depending on the tensioning required on the sheet and suitably arrange the reference means 50 on the bracket 7.
Advantageously, as it is not necessary any particular modification on the motors of the roll-type awning, it is possible to use normal motors with mechanical limit switches on the market. Moreover, none of the two motors is employed as engine braking, which would be virtually detrimental for the same motors.
Of course the invention can be modified or varied in a number of ways without exiting the protection field of the present invention as defined by any one of the appended claims. Further, the materials used to realize the present invention, as well as the forms and dimensions of the single components, can be the most suitable depending on the specific requirements.

Claims

Automatic tensioning system (100) adapted to cooperate with an awning sheet of a motor-driven roll-type awning comprising
- a first electric motor (11) comprising a rotating shaft integral with a winding roll-bar (1) and a motor head (11 A);

- a second electric motor (12) provided with a rotating shaft associated with a tensioning roll-bar (2);

- said awning sheet (3) being secured with a first edge portion to said winding roll-bar (1) and operatively associable with a second edge portion opposite with respect to said first edge portion to said tensioning roll-bar (2), said awning sheet (3) being movable between a retracted position, wherein said sheet (3) is completely wound up about said winding roll-bar (1), and an extended position, wherein said sheet (3) is at least partially unrolled from said winding-roll bar (1);

- control means (20) connected to said first and second electric motors (11, 12) to control the movement of said sheet (3),
said system (100) being characterized in that it comprises
- a support bracket (7) whereon said motor head (11 A) is rotatably mountable,

- elastic means (9) secured to said support bracket (7) and operatively connectable to said motor head (11 A) for biasing the rotation of said motor head (11 A);

- position detecting means (25) comprising at least one position detecting element, adapted to be associated with said motor head (11 A),

- reference means (50) arranged integral with said support bracket (7) and operatively connectable to said control means (20),
said reference means (50) being adapted to cooperate with said position detecting means (25) for generating a signal when, due to a change of the tensioning condition of said awning sheet (3) with respect to a pre-set tensioning condition, the couple applied on said motor head (11 A) causes the motor head (11 A) to rotate, said control means (20) being adapted to receive said signal and to modify or block the movement of the rotating shafts of said first electric motor (11) or of said second electric motor (12) in response to the received signal so that the pre-set tensioning condition of the awning sheet (3) is restored.
System (100) according to claim 1, wherein said reference means (50) comprises at least a first sensor (27) arranged on said support bracket (7) so as to define the pre-set tensioning condition of said awning sheet (3).
System (100) according to claim 2, wherein said first sensor (27) is adapted to generate a signal when said position detecting element (25) moves away from said first sensor (27) for a pre-set period of time.
System (100) according to claim 2, wherein said reference means (50) further comprises a second sensor (16) arranged on said support bracket (7) so as to define a minimum pre-set tensioning condition of said awning sheet (3), said second sensor (26) being adapted to generate a signal when said position detecting element (25) moves close towards said second sensor (26).
System (100) according to claim 3 or 4, wherein said reference means (50) further comprises a third sensor (28) arranged on said support bracket (7) so as to define a maximum pre-set tensioning condition of said awning sheet (3), said third sensor (28) being adapted to generate a signal when said position detecting element (25) moves close towards said third sensor (28).
System (100) according to any of the preceding claims, further comprising a flange (8) provided with a coupling portion (8A) rigidly connectable to said motor head (11 A), a transmission hub (8B) rotatably mounted on said support bracket (7) and a transfer portion (8C) rotatably movable with said motor head (11 A), said position detecting element (25) being mountable on said transfer portion (8C).
System (100) according to claim 6, wherein said elastic means (9) comprises at least a spring having a first end (9A) secured to said support bracket (7) and an opposite end (9B) connected to said transfer portion (8C).
System (100) according to any of the preceding claims, wherein said position detecting element (25) comprises a magnet, and said reference means (50) comprises at least one micro-switch.
Roll-type awning comprising a system (100) according to any of claims 1 to 8.
Method for maintaining or restoring a pre-set tensioning condition of an awning sheet of a roll-type awning provided with a pair of roll-bars operated by corresponding electric motors, characterized in that it comprises the following steps:
a) detecting any change in the tensioning condition of the awning sheet with respect to a pre-set tensioning condition;

b) generating a signal for a change in the tensioning condition with respect to said pre-set condition when said change is greater than a pre-defined amplitude;

c) modifying or blocking the winding / unwinding speed of the awning sheet in response of said signal to restore said pre-set tensioning condition.