TECHNICAL FIELD

The present invention relates to the technical field of overhead door systems. More specifically, the present invention relates to a monitoring arrangement for an overhead door system.

BACKGROUND

Overhead doors systems are often utilized to selectively provide access for large objects, such as vehicles, to a building due to such door systems being able to seal off relatively large entrances at a comparatively low cost.

Overhead door systems generally comprises a door element which may be foldable by means of comprising a plurality of interconnected panels or a single panel in the form of a solid element. Such overhead door systems may be manually operated or automated by means of a motor and a cable arrangement for forcing the movement of the door element.

To allow for the vertical movement of the door element the door system is provided with tracks for receiving wheels of a carrier attached to the door element. The tracks has both vertical and horizontal sections connected by a connecting section for guiding the movement of the door element from a vertical position, i.e. a closed position, and a horizontal position, i.e. an opened position.

For safety reasons, it is important to monitor the cables of the cable arrangement in order to determine if the cable is slacking. If it is determined that the cable is slacking and possibly is about to break, the motor is stopped. The present inventors have identified problems and shortcomings of such prior art systems. Accordingly, an object of the present invention is to overcome or at least mitigate one or more of these problems.

SUMMARY

An object of the present invention is, therefore, to provide a more reliable monitoring device that reduces the risk of false signals causing the motor to stop, as well as proving a monitoring device that allows a faster speed during the start of the downward movement of the door.

In a first aspect a monitoring device for an overhead door system, wherein the overhead door system comprises door blade, comprising a plurality of door panels, being movable between a vertical closed position and a horizontal, opened or overhead position within a side frame, wherein the movement is caused by an operating system comprising at least one motor and at least one cable connected to at least one of the door panels is provided. The monitoring device comprises an arm arrangement comprising an arm and a spring, wherein the spring is connected to the at least one cable, an electrical switch being in operative communication with the at least one motor, wherein the spring of the arm arrangement is configured to detect break or tension drop in the at least one cable, causing the arm to move towards the electrical switch. The monitoring device further comprises a device for damping the movement of the arm in its movement towards the electrical switch.

By having a monitoring device with a means for damping the movement of the arm, it is possible for the system to allow a short slack of the cable before the switch is activated. The device for damping the movement allows for an additional extra seconds in which the cable could become properly tensioned, and thus avoiding a possible false signal.

The device for damping the movement of the spring biased arm may comprise a damping unit.

In one embodiment, the damping unit comprises a damper that is filled with a fluid medium and a piston rod being reciprocable in the damper. The free end of the piston rod may be connected to the arm.

In one embodiment, the arm itself acts as a damping unit.

In one embodiment, the monitoring device is arranged at the lowermost panel section. The at least one cable may be connected to the lowermost panel section. The at least one motor may be arranged in a position above the monitoring device.

In one embodiment, if the cable breaks or slacks, the tension on the spring will decrease and the spring will force the arm towards an activation button on the switch, wherein the movement of the arm arrangement will cause a pressure on the activation button of the switch so as to activate the switch. The activation of the switch stops the at least one motor.

In a second aspect, an overhead door system is provided. The overhead door system comprises a door blade, comprising a plurality of door panels, a side frame and operating system comprising at least one motor and at least one cable connected to at least one of the door panels, wherein the plurality of door panels are movable between a vertical closed position and a horizontal, opened or overhead position within the side frame, and wherein the movement is caused by said operating system, wherein the overhead door system further comprises at least one monitoring device according to the first aspect. In one embodiment, the system comprises a first and a second cable and a first and a second monitoring device, wherein the first cable is connected to the first monitoring device and the second cable is connected to the second monitoring device.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of the example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the example embodiments.

Fig. 1 illustrates an exemplary overhead door system according to one embodiment.

Fig. 2a illustrates an side view of an overhead door system according to one embodiment.

Fig. 2b illustrates a part of an overhead door system comprising a monitoring device according to one embodiment.

Fig. 3a illustrates a monitoring device for an overhead door system according to one embodiment.

Fig. 3b illustrates a monitoring device for an overhead door system according to one embodiment.

Fig. 4a illustrates a block diagram of a damping unit of a monitoring device according to one embodiment.

Fig. 4b illustrates a side view of a damping unit of a monitoring device according to one embodiment.

Fig. 5a illustrates a block diagram of a monitoring device for an overhead door system according to one embodiment.

Fig. 5b illustrates a side view of a monitoring device for an overhead door system according to one embodiment.

Fig. 5c illustrates a side view of a monitoring device for an overhead door system according to one embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the invention will now be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

The present invention relates to a monitoring arrangement and an overhead door system comprising such a monitoring arrangement. Fig. 1 shows a schematic front view of a first embodiment of an overhead door 10 with the features of the invention in a closed state. The overhead door 10 has a door blade 11 for covering a door opening in a wall 12, running in a side frame. In the shown example, the door blade 11 covers a door opening surrounded double sided by the side frame 21, the wall 12 and by a ceiling above. The side frame 21 has double sided a vertical track 13, provided as a guiding element on the left and on the right side of the door blade 11, respectively. Further, the side frame has double-sided a horizontal track 14. The horizontal track 14 runs transversely, in this execution example perpendicular to the vertical track 13, extending rearward to the door blade 11. A connecting portion 15 with a curved shape connects the vertical track 13 and the horizontal track 14, providing a guideway. The horizontal tracks 14 of the side frame are fixed at a rear side under the ceiling. At a front side the horizontal tracks 14 are fixed at the vertical tracks 13 of the side frames, respectively. Accordingly, the overhead door system comprises a pair of vertical tracks 13 and a pair of horizontal tracks 14 connected by a pair of connecting track portions 15. Guiding arrangements 70 are attached to the door blade 11 for interfacing with the tracks.

The door blade 11 is movable between a vertical closed position and a horizontal, opened or overhead position within the side frame. The door panel sections 17a-d are arranged to be moved a distance in an upward or downward direction with respect to the ground level G (illustrated in Fig. 2a). The door panel sections 17a-d are preferably connected to each other by hinges.

The overhead sectional door comprises a plurality of door panel sections 17a-f (illustrated in Fig. 2a). Fig. 1 illustrates an embodiment where four door panels in total 17a-d have been arranged to the doorframe, and Fig. 2a illustrates an embodiment where six door panels 17a-f are used. However, as understood by a person skilled in the art the number of door panels may vary.

The panels 17 are preferably consisting of a rigid material. The height of the panels 17 may be between 150 and 1000 millimeters. The height of the panel may for example vary from 400 millimeters from 675 millimeters, making it possible to suit the door’s style to that of the building. As the skilled person recognizes, the panels may be of any size and material suitable for the application of the overhead door system.

In one embodiment, as shown in Fig. 1, at least one of the panels 17 are connected to a lifting arm 8 connected to a motor 25 for operating the door blade 11 along the tracks. In one embodiment, one of the topmost panels 17 may be connected to the motor 25 by means of a lifting arm 8. Said lifting arm 8 is arranged to transfer the torque from the motor 25 to one of the panels 17 to pull and push the door blade along the tracks. With reference to Fig. 1, the lifting arm 8 is connected to the topmost panel 17.

Fig. 2a shows a side view of an illustrative embodiment of an overhead door system according to one embodiment. The sectional door panels 17a-f are operated by an operating system 20. The operating system 20, also referred to as a driving member, comprises at least one a cable C. The cable C is preferably made in steel.

The operating system 20 at least comprises a motor 25 and at least one cable C. The operating system 20 may comprise a D-hoist, T-hoist or U-hoist system. The operating system 20 is preferably arranged on the top or the end of the tracks 13, 14.

Moreover, the operating system may comprise two torsion springs installed on a shaft above the door opening. The shaft has a cable drum on each end from which door cables C run to the bottom corners of the door leaf 17a. When the shaft is turned, the door moves up or down.

The cable C connects to at least one of the panels 17. Thereby the cable works as a lifting device. Further, one cable may connect end pieces of the panels 17 on both sides of the panels 17, respectively. The cable may run in vertical direction in a slot on both sides of the vertical track 13 of the side frame, respectively.

In one embodiment, the motor 25 is connected to a cable drum for operating the cable. The motor 25 may be connected to a gear box for transferring torque from the motor 25 to the cable drum.

In one embodiment the cable is only connected to the bottommost panel 17a of the door blade 11. Hence the door blade is lifted by means of the cable working as a lifting device for lifting the bottommost panel of the door blade 11 and consequently lifting the entire door blade by means of the lifting force applied to said bottommost panel.

Fig. 2b, shows an illustrative embodiment of two cables C connected to the bottommost panel 17a for the door blade 11. The bottommost panel 17a may be arranged with an end portion 18. The end portion 18 may be in a substantially rigid material, such as plastic, aluminum or steel and serves to protect the end phase of the panel from moisture or mechanical stress.

In the exemplary embodiment shown in Fig. 2b, the end portion 18 is arranged with at least two slits 19. The two slits 19 are preferably arranged at the lower part of the end portion 18, in opposite ends. The two cables C are preferably arranged in a respective U-attachment and through the respective slits 19. The cables are thus arranged at the front side of the bottommost panel 17a.

The cable C is attached to a cable monitoring device 100 configured to detect break or tension drop in the at least one cable C. The cable monitoring device 100 is preferably arranged to detect when a cable gets too loose, slacks or breaks. When it is determined that the cable is too slack, the movement of the door panels will be stopped. The movement of the door panels are stopped by stopping the at least one motor 28.

Fig. 3a and b illustrates embodiments of a cable monitoring device 100. Starting in Fig. 3a, the cable monitoring device 100 comprises a switch 120. The switch 120 is in operative communication with the motor 28. The communication may be a direct communication, or a communication via a controller. The switch 120 is connected to a stop circuit. Once the switch 120 is switched into an open state (activated), the motor 28 is stopped and thus the movement of the door panels 17 are stopped. The switch 120 is preferably an electrical switch 120. Moreover, it preferably has an activation button 128 (as shown in Fig. 3b). The activation button 128 activates the switch, i.e. changes the mode of the switch.

The cable monitoring device 100 further comprises an arm arrangement comprising an arm 130 and a spring 124. The arm 130 is spring forced by the spring 124. The arm 130 is arranged in conjunction with the cable C. If the cable C breaks or slacks, the tension on the spring 124 will decrease and the spring will force the arm 130 towards the switch 120. The movement of the arm arrangement will cause a pressure on the activation button 128 on the switch, and thus activate the switch 120 (i.e. activate the stop circuit). The movement of the arm is indicated by the arrow referenced M. The movement M is in the direction of the extension of the spring 124.

The arm 130 may have different shapes and dimensions, as long as it has a surface that could push the activation button 128 on the switch. The arm is in a shape that allows it to push the activation button 128. In one embodiment shown in Fig. 3b, the arm 130 could be T-shaped. The arm 130 may comprise a main body 132 extending in a vertical direction, as well as a top portion 134 that extends in the horizontal direction. The top portion 134 is arranged on top of the mains body 132. The main body 132 and the top portion 134 thus creates a T-shaped arm. The top portion 134 has a first surface 134a and a second surface 134b. The first surface 134a is configured to touch the activation button 128 on the switch 120. The second surface 134a is facing the main body 132 and the spring 124. The cable C is preferably connected to the main body 132 of the arm 130.

It is beneficial if the cable monitoring device 100 only stops the motor 25 if the cable C is sufficiently slack in order to avoid unintentional stop of the motor. The present inventors have thus realized that this could be achieved by introducing delay in activating the switch. By adding a devices that damps the movement of the arm that activates the switch such a delay is introduced.

The cable monitoring device 100 thus further comprises a device 110 for damping the movement of the arm arrangement as the arm 130 is moved towards the electrical switch 120. The device could also be referred to as a device for securing a soft movement of the arm 130, or a device for causing a delay in activating the switch 120.

The device 110 for damping the movement may be or comprising a damping unit 110. The damping unit 110 is configured to damp the movement of the arm 130 of the arm arrangement. The damping unit 110 slows down the movement of the elements of the arm arrangement so as to delay the activation of the switch 120.

The damping unit 110 shown in Fig. 3a-b may be constructed in different ways. In one embodiment, as shown in Fig. 4a, the damper unit 110 comprises a damper 112. The damper is filled with a fluid medium 116. The fluid medium may be air, gas, oil, water or other types of liquids. The damper unit 110 may further comprises a piston with a piston rod 114 being reciprocable in the damper. The free end of the piston rod 114 is connected to the arm arrangement.

Parts of the damping unit 110 may be constructed by a plastic material. Such material may for example be polyamide or polyoxymethylene.

The damper 112 may be a pneumatic cylinder or a hydraulic cylinder. Fig. 4b shows another embodiment of a damper where a coil spring 118 is attached on the piston rod 114. In yet one embodiment, a coil spring is mounted within the damper. If the coil spring is within the damper, the coil spring is arranged between the piston and the bottom piece in the damper.

Fig. 5a shows another embodiment of a cable monitoring device 100. In this embodiment, the device 135 for damping the movement of the arm arrangement of the arm 130 is part of the arm 130 itself. The arm arrangement thus has a damping arrangement inside itself so as to reduce the speed of its movement towards the switch 120. This may be achieved in many ways. Fig. 5b and c are illustrative embodiments of a cable monitoring device 100. In this embodiment the arm 130 acts as a piston. The arm 130 is arranged in an enclosed space 144 comprising the switch 120 and the spring 124. The enclosed space 144 creates two areas, a first area 146a and a second area 146b. The first and second area 146a, 146b are separated from each other by the arm 130.

In one embodiment, as shown in Fig. 5b, the arm 130 is arranged with a small distance from the walls of the enclosure so as to create an air passage 142 between the two areas 146a, 146b. The pressure that have been built up in the first area 146a slows down the movement of the arm 130. In yet one embodiment, as shown in Fig. 5c, the arm 130 extends along the whole width of the enclosure so that no air passage is created at the ends. Instead, the arm 130 is arranged with at least one air duct 147 that creates an air passage between the two areas 146a, 146b. In the embodiment shown in Fig. 5c, two air ducts 147 are arranged on the arm 130. The air ducts 147 are preferably arranged on both sides of the main body 132. The invention has been described above in detail with reference to embodiments thereof.

However, as is readily understood by those skilled in the art, other embodiments are equally possible within the scope of the present invention, as defined by the appended claims.