Abstract:
A safety system for entering and exiting garage doors and entrances comprises a warning sign adapted to be placed by an attachment cable at a primary line of sight of a driver of a truck during lowering and raising movement of the door. A delay circuit is provided to facilitate a movement of the sign in such a manner that the sign will always appear first in the primary line of sight of the driver to eliminate a possibility of collision between the truck and the door. A moving mechanism is adapted to lower the sign into an operational position and provided to keep the sign in non-operational retracted position when the door is completely open to ensure clearance for moving truck. The warning sign is activated by a warning sign activating device such as a motor-driven assembly. The door is activated by a door detector adapted to transmit signal to a door control panel operating the movement of the door by a door motor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is claim the benefit of a Provisional Application No. 60/280,853 filed on Apr. 3, 2001. 
    
    
     The present invention is related to a safety system and more particularly to a warning sign safety systems for entering and exiting garage doors and entrances. 
     There is known Canadian Patent 2,015,205 related to a safety system to exiting garage doors having a door operator with a main control circuit, electrical motor and a reversible drive train, wherein the main control circuit provides one of four modes of operation of door opening, door stopped open, door closing and door stopped closed. 
     There is also known Canadian patent 2,312,311 related to a garage door status indicator kit comprising a sensor for emitting an output signal if the garage door is open, an indicator means mountable on the wall in the garage interior for receiving the output signal and power source connecting means to connect the sensor and indicator. 
     There is also known U.S. Pat. No. 5,529,274 related to a remote control motor-driven drum to wind and unwind a cord which holds a self-balancing sign suspension system, wherein the motor, which is reverable, is remotely controlled either by wires leading between the motor and a switch, or by radio control. 
     BACKGROUND AND OBJECT OF THE INVENTION 
     There is a continuous problem in small and large warehouses with one or many garage doors: the doors are frequently damaged by big vehicles such as trucks, lift trucks, fire trucks or buses as the vehicles go through the doors. According to unpublished statistics, annual repair bills for this damage may run from $250,000 to over $1 million per warehouse. These doors can be located in such places as municipal warehouses or distribution points of multi-national soft-drink and breweries all over North America. Besides, the damage is not only done to the doors, but to the trucks as well; each accident could cost around $2,000.00 per truck. Considering the fact that, on average, 30 to 100 accidents are registered per year for each large warehouse, this cost must be multiplied accordingly. 
     In addition, if the warehouse is located in a cold climate where, during the winter, the temperature could easily fall below −20° C. (12° F.) it is necessary to use standby heating systems to maintain the proper ambient indoor temperature (at least at 15° C.) to prevent cold air from spoiling the stored goods until the damaged door is repaired. In general, it may take 2-3 days to fix the damaged door, and the owner of the warehouse is forced to spend substantial funds for the additional heating of this area of warehouse. 
     The reason the vehicles cause damage to the doors is due to the fact that when crossing the door entrance, whether going inside or outside, the driver&#39;s primary line of sight is usually in front of him to make sure that he does not hit a pedestrian. Commonly in the industry, there are red/green warning lights controlled by different types of vehicle detectors connected to a control panel. Detectors, such as photocells, magnetic activators or other types, are provided to see the vehicle to activate the door to open. While the door is still not completely open, the red light is “on” to keep the driver from moving. The light turns green only when the door is completely open, indicating that the driver is free to pass without any restriction. 
     However, very often the driver does not pay attention to these red/green lights because they are placed not in his primary line of sight in front of him because the warning lights are usually installed on one or both sides of the garage door. This is a secondary line of sight of the driver. Another reason for such accidents is due to daylight: when the driver is exiting the garage during the day, it is darker inside than outside; the daylight blinds the driver, and he has difficulty seeing any warning signals. At many locations, vehicles are sensed when they are less than 10 feet from the door. At 5 km/hour, the driver does not have enough reaction time to stop before crashing into the door. Also, if the driver is in the middle of a 25-foot wide door and it starts to close, he will hardly see the warning lights on the side of the entrance. Some light systems are activated by a switch that needs a 6″ travelling distance from the door before the light turns red. 
     The object of the present invention is to eliminate this problem and to substantially reduce expenses caused by those accidents. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention uses an innovative system provided to hold a warning sign that will be lowered down to be suspended in front of the truck at the driver&#39;s eye level. Such advantageous positioning of the warning sign in the primary line of sight will be definitely seen by the driver and will warn him that the door is not completely open. The warning sign may be activated by any kind of detectors. The same detector may be used for the activation of the garage door as well. The warning sign is lowered when the door starts to close, and stays there while the door is opening. When the door is completely open, the warning sign will be raised, thus allowing the driver to exit. Neither the warning sign nor the door will be lowered as long as the vehicle is in the vicinity of the door to eliminate accidental damage to the door. Once the door entrance is free, the warning sign will go down, and only when it is completely down will the door start to close. Optionally, it is possible to install a special relay to provide an additional delay right after the sign is down to increase the reaction time for the driver before the door will start to close. As a result, the warning sign will be suspended in the primary line of sight of the driver in case the door will start to close or is not completely open, thus giving the driver more time to react. 
    
    
     DESCRIPTION OF DRAWINGS 
     FIG. 1 shows a schematic block-diagram of the warning sign system according to the present invention. 
     FIG. 2 shows a warning sign suspension system according to the first embodiment of the present invention. 
     FIG. 3 shows a warning sign suspension system according to the second embodiment of the present invention. 
     FIG. 4 shows a warning sign suspension system according to the third embodiment of the present invention. 
     FIG. 5 shows a warning sign suspension system according to the fourth embodiment of the present invention. 
     FIG. 5A shows another modification of the embodiment of FIG.  5 . 
     FIG. 6 shows a warning sign system according to the fifth embodiment of the present invention. 
     FIG. 7 shows a warning sign system according to the sixth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, FIG. 1 shows a schematic block-diagram of the warning sign system of the present invention comprising various vehicle actuators, such as detectors and activators provided for both functions: to detect vehicles to send a command to activate garage door  13  and then to activate a warning sign system of the present invention. It must be emphasized that it is possible to use any of known detectors or activators for the purpose of the present invention, such as a push button ( 1   a ), photocell or reflective beam ( 1   b ), remote control ( 1   c ) installed on a vehicle or truck  1  or a magnetic floor detector ( 1   d ) facilitating the same function. The detectors  1   b  or  1   d  and activators  1   a  or  1   c  are connected by any means to a door control panel  4  to activate a door motor  5 . In this case, door control panel  4  may be relay logic, PLC electronic circuit board, automatic system or any other means used for the same function. Detectors  1   b  or  1   d  and activators  1   a  or  1   c  are also connected a control panel  2  of the warning sign system, which could also be relay logic, electronic circuit board, automatic system or any other means. Control panel  2  of warning sign system is connected to a warning sign motor  3  activating lowering or rising of a warning signal  14  attached to the motor  3  by different means, such as system of cables  12 . Door entrance is provided with a detector  6  provided to completely close an opened door  13  and sensor or photocell  8 . There may also be installed additional alarm means in the vicinity of the door, such as warning lights  10 , alarm siren  9  and stroboscopic lights  11 . Elements  8 ,  9 ,  10  and  11  are optional and can be installed inside or outside the garage entrance. 
     In operation, when detectors  1   b  or  1   d  or activators  1   a  or  1   c  detect vehicle  1  approaching the door entrance, they send a signal to door control  4  to open the door  13 . This signal will be intercepted by control board  2  of warning sign system to activate the motor  3  of the warning sign system. The motor  3  will activate sign  14  to be lowered down. As soon as the sign  14  will go down, the signal from door control  4  delayed by a predetermined time by a signal from control board  2  activating the motor  3 , will activate the door motor  5  to close the door  13 . Optionally, the sign  14  may already be down even before the detectors  1   b  or  1   d  or activators  1   a  or  1   c  are activated. As soon as door  13  is completely up, the sign  14  will be raised up and warning light  10  will turn “green”. When there is no vehicles in the vicinity of the door  13 , activators  1   a  or  1   c  will send a signal to the door control board  4  to close the door  13 . This signal will be intercepted by the control board  2  of the warning sign system to activate the sign  14  to start lowering by means of the motor  3  of the warning sign system. The warning light will turn “red”. As soon as the sign  14  starts lowering down, the signal from door control  4 , delayed by a delay means will activate the door motor  5  to close the door  13 . In this case the delay means could be a relay or any other similar electric delay system which may be incorporated into the door control panel  2  or the warning sign control panel  2  will facilitate a delay on a predetermined period of time necessary for the warning sign to be lowered down completely before the door will start to close. If vehicle  1  arrives at the entrance when the door  13  is still up and the sign  14  is already down, the door  13  will stay up and sign  14  will also go up. In case the door  13  starts to close and sign  14  is already down, door  13  will again go up, and as soon it is up, the sign  14  will also go up. In case vehicle  1  is very close to the door and neither warning sign system nor door control system are able to warn the driver, another safety feature, such as sensor or photocells  1   b  or  8 , may be activated together with stroboscopic lights  11  and alarm siren  9  to additionally warn the driver. When door  13  is completely closed, the sign  14  may stay down or go back up until the next vehicle comes to the door. Warning light  10  is always “red” until door  13  is open and sign  14  is up. In case vehicle  1  is backing up towards the entrance and the driver is not able to see the warning sign  14 , detectors  1   b  or  1   d  or sensor  8  will activate the sound alarm  9  to prevent accident. It must be emphasized that the warning sign  14  of the present system is always lowered when the door  13  is in movement, or a few second before the door starts to close. 
     Present system uses a reversible motor provided to lower the warning sign  14 . There are numerous possibilities of designing the warning sign arrangement to provide the same result which will cover the broadest scope of the present invention. The invention utilises an innovative system provided to support the sign  14 . In some of the embodiments of the present invention, such system comprises a motor-driven drum as a winder to wind and unwind a cord or a number of cords or straps supporting the sign  14 . The sheaves or the attachment to the sign  14  are not important, as they receive the cord and lead it from the motor-driven drum to the warning sign, wherein the motion of the drum serves to raise and lower the warning sign. The user may fix the motor-driven system of the present invention indoors or outdoors. The speed, delay and duration are programmable or manufactured parameters, and can vary. The motor  3 , which is reversible, is remotely controlled either by wires leading between the motor and a switch, or by radio automated system, electronic circuit or electrical (relay logic) systems provided to always raise the warning sign  14  once garage door  13  is completely open and to lower it before the garage door  13  starts to close or open. A shelter (not shown) can be provided to protect the system from the elements. 
     FIGS. 2-7 shows different modifications of the motor-driven portion of the warning sign system of the present invention. FIG. 2 shows a first embodiment comprising a motor  3  connected to a rotatable shaft  18 . Warning sign  14  is suspended on shaft  18  by means of pair of cables  12 . Motor-driven drums  20  are adapted to raise or lower sign  14  into an operative position. All system is fixed to the support by means of bearings and bracket (not shown) or any equivalent means. 
     FIG. 3 shows a second embodiment of the present invention comprising a tubular motor  28  connected to a drum  32  of a larger diameter placed over and connected to the motor  28  by means of a pin  34 . Rotation of the motor  28  transferred to the drum  32  is provided to wind or unwind cables  12  to which warning sign  14  is attached. 
     FIG. 4 shows a third embodiment of the present invention comprising a motor-driven assembly mounted to an upper edge of the door entrance and including the motor  3  connected to the shaft  18  supporting a drum  20  by means of bearings (not shown). Warning sign  14  is suspended by means of cable  12  and a metal lazy-tongs system  42 . All sign system is attached to the support by means of bracket (not shown) or any other means. 
     FIG. 5 shows a fourth embodiment of the present invention comprising a motor  3  connected to a shaft  18  supporting a warning sign  14  by means of a rigid plate  44  pivotally connected to shaft  18 . A joint  26  mounted on the rigid plate  44  is provided to prevent rigid board  44  from being damaged if hit by vehicle  1 . The motor  3  is adapted to pivot the rigid plate  44  between an operable and non-operable positions, wherein said rigid plate  44  is completely retracted to clear the door entrance. 
     FIG. 5A is another modification shown of FIG. 5, wherein all motor-driven system supporting the warning sign  14  is mounted on a side of the door entrance. In this embodiment the dimensions of the sign  14  can be larger that the width of the garage entrance to facilitate a better visibility of the sign  14  in case the vehicle  1  is backing up towards the entrance. 
     It must be emphasized that embodiments of FIGS. 5 and 5A may be installed inside or outside of the door entrance or exit without departing from the scope of the present invention. 
     FIG. 6 shows a fifth embodiment of the present invention comprising a mechanical version of the warning sign system to be fixed to the bottom of the door  13  and comprising a sign  14  attached to a pivoting arm  40  adapted to be pivoted by means of pivot  36  mounted on bracket  46  connected to the lower edge of the door  13 . Pivotal movements of the arm  40  are restricted by a first stopper  50  provided to maintain the angle of the arm  40  when the door  13  is between opened and closed position and a second stopper  52  mounted on the upper frame of the door entrance to facilitate the pivoting upward movement of the arm  40  when the door  13  is open. Sign  14  is also provided with a set of wheels  54  mounted around a lower portion of said sign  14 , to facilitate rolling movement of the sign  14  in contact with the ground while the door  13  is about to be closed and the sign  14  is pivoted into retracting position. A joint  26  located on the pivoting arm  26  is provided to prevent the sign  14  from being broken in case of an accidental hit by the vehicle  1 . 
     FIG. 7 shows a sixth embodiment of the present invention comprising a solenoid  56  or any locking device connected to mechanical drums  58  provided with cables or chains  60  to open the door  13  manually. The solenoid  56  is provided to prevent the door  13  from being opened or closed in case sign  14  is not down. A warning sign control  2  is interconnected with the solenoid  56 . Once the sign  14  is down by means of a motor  3 , the operator will be free to open or close the door  13 . In this embodiment, to open or close the door, the sign  14  has to be lowered down before the solenoid or locking device  56  will automatically allow any movements of the door  13 . 
     Thus, it can be seen that the objects of the present invention have been satisfied by the structure presented hereinabove. While in accordance with the Patent Statutes, only the best mode and preferred embodiments of the present invention have been presented and described in detail, it is to be understood that the invention is not limited thereto or thereby. Accordingly, for an appreciation of the true scope and breadth of the invention, references should be made to the following claims.