Patent Application
20120073200
The invention relates to a door control system with obstacle detection.
1. Introduction
When a door is opened or closed, it happens that obstacles formed by objects or persons may accidently be situated on its travel. It is necessary to protect both the door and these obstacles by means of a control system equipped with a safety function aimed at managing the accidental presence of obstacles, in particular by stopping the door in its travel when it encounters one and moving it away from the obstacle in order to be able to remove it. Said safety device must react promptly and reliably since tardy reaction or an absence of reaction may cause firstly dangerous crushing or overturning of the obstacle and secondly damage to the door.
Moreover, such a door control system should be able to make it continue its initial movement, as quickly as possible and automatically, as soon as the obstacle has been removed. This requirement is dictated in particular by considerations such as energy savings, protection against external attacks such as wind, rain and theft, the maintenance of controlled atmospheres (for example in refrigerated storage, clean rooms, and so on) etc. In addition, said door control system must on this occasion protect both the door and the obstacle in order to avoid damaging them.
2. Background art
In the prior art such control systems with obstacle detection are known, which offer a certain degree of protection during operation of the doors, and in particular flexible fast-acting doors, through the detection of any obstacles that might be situated on the travel of the door.
Some obstacle detection systems are contactless, that is to say they enable an obstacle to be detected before impact. The patent U.S. Pat. No. 7,034,686 B2 for example discloses a proximity detector provided with an antenna, which triggers a command to stop and reverses the closure of the vertical door when the magnetic field created by the antenna is disturbed by a close object. Such as system lacks precision given that the magnetic field may radiate outside the closure plane and thus cause false alarms triggered by objects situated close to the door but not underneath it.
Obstacles may also be detected using a complex computer system such as the one disclosed in the patent U.S. Pat. No. 5,198,974 A1 in which the variation in the speed of a door pulley is recorded and compared with a reference speed curve stored in memory, in order to establish whether or not there is an obstacle.
Other detection systems may comprise contact detectors disclosed for example in US 2007/0261305 A1. Detection of a contact during the door closure phase generates a signal, generally electrical, which causes the stoppage of the door closure phase.
Each of documents U.S. Pat. No. 7,034,682 B2, U.S. Pat. No. 6,989,767 B2, U.S. Pat. No. 5,198,974 A and US 2007/0261305 A1 concerns safety systems for doors in which, as soon as the obstacle is detected, the motor stops, reverses its direction of rotation in order to open the door completely and stops definitively when the door is completely open. The door can be closed once again by manual intervention.
The document U.S. Pat. No. 4,452,292 concerns a door control system where, after detection of an obstacle during closure therefore, the motor stops and reverses its direction of rotation to enable the obstacle to be removed, and then resumes its rotation in the direction of closure. Different cycles are described in the case where the obstacle has not been removed in time. However, in the cycles described in this document, the door closes on each occasion at constant speed which, firstly, if the speed is high, does not particularly protect either the door or the obstacle and secondly, if the speed is low, gives rise to an excessively long closure time.
A need therefore remains with regard to a simple and reliable door closure system, able to make it continue its initial movement, after repeated impacts on an obstacle, as quickly as possible and automatically as soon as the obstacle is removed, while on this occasion protecting both the door and the obstacle.
The first aim of the invention is to procure a simple and reliable door control system, able to make it continue its initial movement after repeated impacts on the same obstacle as quickly as possible and automatically as soon as the obstacle is removed, while on this occasion preventing damage both to the door and to the obstacle.
The exemplary embodiments of the present invention comprises in particular a system for controlling a door intended for closing a structure opening or any type of opening, enabling driving from an initial control position, Pi, of its travel in a first direction at a speed v1 as far as a final control position, Pf, said control system comprising a safety function comprising means for performing the following steps in the event of impact with an obstacle obstructing the path of said door in the first direction:
(a) Detection of the impact, stoppage of the motor, and storage of the impact position, Pimpact, followed by
(b) Reversal of the travel of the door by driving it in a second direction, opposite to the first, at a speed v2 as far as a waiting position, Pwaiting, predetermined so as to leave sufficient space for removing the obstacle;
(c) After a waiting time, Δtwaiting, in the waiting position, Pwaiting, driving of the door in the first direction at the speed v1 as far as a predetermined position P3 situated upstream of the impact position Pimpact, at which point the speed of driving the first direction is reduced to the value v3, with 0<v3<v1;
(d) If the door driven in the first direction at the reduced speed v3 no longer detects an obstacle at the position Pimpact, increasing the speed of driving in the first direction to the value v1 until the door reaches its final control position Pf;
(e) If on the other hand the door driven in the first direction at reduced speed v3 once again detects the obstacle at the same position Pimpact, the cycle defined by steps (a) to (c) is repeated and step (d) is executed if the conditions defined therein are fulfilled;
(f) If after a predetermined number N of repetitions of said cycle the obstacle is still detected, driving of the door in the second direction at speed v2 and stopping of the door at a predetermined stop position Pstop, until manual reactivation of the control system.
The advantage of the invention is to keep a door in operation despite the presence of an obstacle at the position Pimpact on its travel and to enable it to continue its initial movement automatically as soon as said obstacle is removed, through a simple design reconciling both the operational requirements, that is to say a sufficiently high normal speed of movement v1 of the door, with the intention to prevent damage both to the obstacle and to the door by reducing this speed to v3<v1 close to the impact position Pimpact, in order to reduce the energy of a potential impact (energy ∝v2), should the obstacle not have been removed at the time of the second passage of the door through the position Pimpact. The number n of passages of the door through the position Pimpact defining n cycles is limited to a maximum value N in order to limit the number of impacts at reduced speed v3 in the case of prolonged maintenance of the obstacle on the path of the door, which helps to protect it. In the same way the energy costs are compressed. In the case of impact at a different height, the value of the number n of cycles is reinitialised to 1.
These aspects as well as other aspects of the invention will be clarified in the detailed description of particular embodiments of the invention, reference being made to the drawings in the figures, in which:
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The flow charts and graphs are also representative in nature, and actual embodiments of the invention may include further features or steps not shown in the drawings. The exemplification set out herein illustrates an embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
The present invention applies to any type of door, the definition of which is to be taken in the broad sense, comprising any structure for the reversible closure of an opening or doorway. The door according to the invention may be rigid or on the contrary flexible, and movement thereof enabling reversible closure of the opening may be linear or angular. The door may be mounted vertically, but may also be inclined, or even horizontal in the case of horizontal openings.
In the context of the present invention, the first direction defines the direction of movement of the door for passing from the initial control position P, to the final position Pf. The “normal” movement speed, that is to say unless provided for to the contrary in the context of a specific step of the safety function, has the value v1. If the command is to close the door, then the first direction defines the direction of closure and the speed v1 the closure speed. Conversely, if the command is to open, the first direction defines the direction of opening and the speed v1 the opening speed. In a similar manner, the second direction, being opposed to the first, defines the direction and speed v2 of opening and closing respectively.
According to a preferred embodiment, the value of Δtwaiting is constant for all the N cycles. Alternatively the value of Δtwaiting increases after each cycle. The advantage of the latter embodiment is that, if removing the obstacle from the path of the door proves to be difficult, extension of the period of time to the following cycle gives more time to the operators to remove the obstacle. According to another embodiment of the invention, the waiting position Pwaiting is fixed for all the N cycles and may be the initial control position Pi. However, said waiting position may change with the number of cycles n and therefore of course also differ from the initial position Pi.
Once the time Δtwaiting has elapsed, the door starts off again in the first direction at the speed v1, as far as a position P3 situated upstream of and close to the impact position Pimpact. At the position P3, the control system gives the instruction to reduce the speed from v1 to the value v3, with 0<v3<v1 (see
If the obstacle has been removed and the system no longer detects an impact when the door reaches the impact position Pimpact, the command is given to increase the speed of movement to the “normal” value v1, which is maintained until the door reaches its final control position Pf (see
If on the other hand the system detects a new impact at the position Pimpact, since it has not been possible to remove the obstacle in time, the system initiates a second cycle by stopping the motor, determining whether the maximum number N of cycles has not been reached, reversing the travel, etc. If the obstacle is not removed after a predetermined number N of impacts, the system leaves the loop, reverses the travel of the door in the second direction and drives the door at the speed v2 as far as the position Pstop, when the door is stopped until the control is manually reactivated. This case presents itself for example if the obstacle cannot be moved or if there is no person to move it. The stop position Pstop may correspond to the initial position Pi, or take any value upstream (with respect to the first direction) of the impact position Pimpact.
If during a cycle a new impact occurs at any position different from the position Pimpact of the first impact, the cycle counter is reinitialised to n=1 and the safety function is applied once again for this new impact. According to a variant of the invention, the case of a second impact erases the memory of the first impact. However, should the second impact have taken place upstream (with respect to the first direction) of the position of the first impact Pimpact, it may be dangerous to ignore the possible presence of the first obstacle once the second has been removed from the path of the door. To overcome this problem it is possible to keep in memory several impact positions during the application of a safety function, the system thus managing a “cascade” of impacts by defining the positions Pimpact,k, P3,k, Pwaiting,k distributed over the path lying between the initial and final control positions Pi and Pf, and a number of cycles nk where k refers to a particular impact (see
The control system according to an exemplary embodiment of the invention preferably controls a door that is a flexible shutter, either in the form of a flexible material (for example a textile fabric or a polymeric or metallic film) or consisting of rigid elements connected to each other in a movable fashion, such as a slatted shutter. In the case of flexible shutters, the path of the shutter is generally linear, such as for example a vertical shutter the opening of which is generated by the upward movement of the shutter. Alternatively, the door may be rigid, the path of which is either linear or angular, for example if the door is mounted on hinges or a rotation shaft.
One exemplary embodiment of the invention is shown in
Preferably the “normal” speed in the direction of closure of the door is less than the opening speed, in particular in the case of a flexible or rigid vertical door with linear path, the closure of which is generated by the descent of the door since, in this case, an impact can take place only in the case where the first direction is the closing direction. The energy of such a potential impact is thus reduced in order to prevent straightaway significant damage to the door and to the obstacle by lowering the door at a speed v1 less than the speed v2 of opening in the second direction, since the door should not normally encounter the obstacle when it is rising.
While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.
