Technical Field The invention concerns the method for controlling and checking of the mechanical warning for level crossing warning light equipment through the barrier beam's electromechanical drive and the invention also concerns the equipment for executing this method.

Background of the Invention

Two alternative principles for barrier beam drivers with an electromechanical transfer of energy are used on railway crossings until now : a) a drive by an electric motor only for opening the barrier - otherwise known as a drive with passive lowering, i.e. using gravity or a spring. b) a drive by an electric motor with reverse operation - otherwise known as a drive with forced lowering.

The actual choice of the principle depends on the concept of the safe operations of level crossing warning light equipment with barriers that was adopted by the relevant railway administration. Here are further details on both principles.

Drives with passive lowering :

Drives using electric motors are used only for opening barriers in the Czech Republic. In the basic, i.e. lifted position the unbalanced barrier beam is positioned vertically and it is stabilised by one electro-magnetically-controlled latch which is electrically excited in this position. By issuing the command to lower the barrier beam the latches exciting current is interrupted, thereby releasing the driving shaft holding the barrier beam. The barrier beam subsequently lowers due to its unbalanced weight.

The advantage to this solution is the lowering of the barrier beam independently of the delivery of electricity and the functioning of the motor. Disadvantages include the risk of the premature lowering of the barrier beam in the event of a malfunction in the latch or its electrical circuits, which means the barrier beam is lowered without a command for the lowering being issued, and also the risk winding of the motor armature is connected to the batteries' full voltage. When moving downwards, the resistance bypass is connected in parallel to the motor armature's winding, and shortly before the end positions are reached the armature's winding is disconnected from the battery. The brake magnet is excited with a delay so that it only turns on the brake during the run out of the motor.

The drive contains a spring or counterweight so that, during an electrical failure, the barrier beam will bend so far from the upper end position (from the position of the centre of gravity) that the beam will fall to the closed position with its own weight. The bypass (shunt connection), made up of a serially-connected resistance and blocking rectifier, is connected in parallel to the motor armature's winding. It, together with the motor armature's winding, makes an attenuator when lowering and acts as a braking current circuit after the battery is disconnected. The excitation motor winding is disconnected with a delay when reaching the barrier beam's lower end position and after the brake is switched on the standing blocking equipment, e.g. a latch, is put into motion in the gear box through the relay and against the effect of the spring, turning off the braking magnets.

Both of the two aforementioned inventions are concerned with the regulation of engine speed rotations, with no connection to arranging the lowering of the barrier in the prescribed time. It also does not resolve the complex functions of the mechanical warning, which also means the locking of the barrier beam in the upper end position and the scanning of the barrier's position. While file DE 1 105 453 deals with a combination of gravitational and motor-driven lowering, gravitational lowering is described as for emergencies and only works during a power failure.

Summary of the Invention

The method of the control and check of the mechanical warning for level crossing warning light equipment through the electromechanical barrier beam drive and the equipment for executing this method according to the invention eliminate the disadvantages of the solutions used until now. The essence of the invention is that the lowering of the barrier beam is always executed simultaneously, in a regulable interval, by two independent lowering principles, gravitational and forced, while the gravitational lowering is secured by the weight of the beam and the forced lowering by an electric motor; which ensures that the barrier beam is lowered in the required short that the barrier beam does not lower at all or lowers late in the case of extremely adverse weather conditions, however.

Drives with an electric motor and reverse operation: In the basic, i.e. lifted position, the balanced barrier beam is stabilised mechanically. After the command to lower the barrier beam is issued, the mechanical stabilisation is cancelled with the use of motor-driven power. The barrier beam subsequently lowers by force, i.e. by use of the motor.

The advantage of such a solution is the elimination of the risk of the premature lowering of the beam due to a malfunction. The fact that the barrier beam may not lower, or may lower late in the case of an interruption of the power supply to the motor or in the event of a motor malfunction is a disadvantage.

The problem of the motor-controlled drive is covered by U.S. patent 6,307,339, which concerns the regulation of the barrier motor driver's revolutions on the basis of information from the sensor monitoring the charge of the motor armature with the use of the dynamic braking of the DC motor, where the motor behaves as a generator, by connecting the impedance (speed limiter) in parallel to the motor armature. The invention, however, only focuses on the motor itself and the various technical solutions for the scanning and regulation of the motor revolutions. The US Patent does not deal with the principle of the submitted invention; it does not resolve the method of securing the barrier beam in the upper end position and the evaluation of the beam's end positions. In this US file the regulation of the motor is performed on the basis of the scanning of the motor parameters. File DE 1105453, which is the closest status of the technology to the submitted invention, resolves the electric motor drive of the beam, especially for railway crossings. The patent deals with the control of the driver motor so that the lowering period is different from the period for raising the barrier beam. The batteries that give the operational voltage is divided into several identical parts, preferably two halves, which are connected in serial (one after another) when the beam is moving up, and connected in parallel (next to each other) when moving down. When using a shunt motor, an excitation winding remains connected to the full voltage of the battery, while the voltage on the motor armature's winding is altered. When moving upwards, the period of time after the vital command for the lowering has been issued. Furthermore the barrier beam cannot lower without a vital command to lower being issued, which assures the locking of the barrier beam in the upper end position, simultaneously, by two independently-operating brake circuits, each of which independently exert braking torque sufficient to securing the barrier beam in the upper end position, with the regular and automatic testing of their functions and the evaluation of their functionality. And, ultimately, reliable information on the actual end positions of the barrier beam must be obtained. This is obtained, simultaneously, from two independently-acting barrier beam position angle sensors with a comparison of their functions. The barrier beams are lowered and raised at a regulable interval by the electronic regulation of the electric motor's revolutions.

It is an advantage to proceed so that a command to lower the barrier beam is issued on the basis of a command signal. This leads to a cancellation of the securing(locking) locking of the barrier beam in the upper end position and the control unit turns on the electric motor, which lowers the beam until it reaches a previously chosen angle with the horizontal level. At this point the control unit issues a command to turn off the electric motor. The main driveshaft position sensor constantly scans the angle direction of the main shaft bearing the barrier beam and the control unit performs an evaluation of the beam's end position. It is advantageous when more than one sensor scans the position of the barrier beam and when the sensors compare the information, while the upper and lower end positions of the barrier beam are not evaluated when the data obtained does not agree.

The essence for the equipment that executes the described method pursuant to the invention is that the driving elements of the barrier beam driver are grouped into separate branches, independent of the locking elements and that the barrier beam is secured in the upper end position by two functionally-independent braking circuits with the testing of their functions and the evaluation of their functionality.

The essence for the equipment that executes the described method pursuant to the invention is that the driving elements of the barrier beam driver are grouped into separate branches, independent of the locking elements, and that the barrier beam is secured in the upper end position by two functionally-independent braking circuits with the testing of their functions and the evaluation of their functionality. The electric motor's shaft is connected to the main driveshaft through the friction coupling and second gear. The second gear is also connected to the brake shaft simultaneously through two free engine clutches. Two of the brake circuit's independent electrically- classified friction brakes, functioning as locking elements, are attached to the brake shaft. The sensor and measurement shaft is connected to the main drive shaft with the assistance of the third gear. Two angle sensors attached to the sensor and measurement shaft are connected electronically to the control unit. The control unit controls the bidirectional driving motor and processes information about the angle direction of the main drive shaft from the sensors. The third gear is comprised of cogwheels with direct gearing. The sensors could be rotational angle sensors, for example. The main advantage of this invention is that it ensures the safe operation and functioning of the mechanical warning for level crossing warning light equipment. The solution according to the invention combines the drive with passive and forced lowering and thereby concentrates the advantages and eliminates the disadvantages of the principles specified in the background of the invention. The advantageous arrangement of the functional elements leads to the interaction of both methods, during which a new and higher effect is reached than for the originally-used solutions. This new arrangement of the functional elements consists partially in the doubling of the crucial elements and their functions.

The advantage of the submitted invention is the solution of the lowering of the barrier beam in the prescribed time interval, which is in most cases within 12 seconds from when the lowering command is issued, as is specified in Czech standard CSN 342650 (within 10 seconds) and in other national railway specifications, e.g. 412 UPUTSTVO - the Serbian Railway Standard (within 12 seconds). It thus achieves the high reliability of the accumulation of motor-driven and concurrently gravitational lowering, particularly in the case where the motor fails, or conversely when adverse weather conditions, strong winds, gales, etc. act against the gravitational lowering of the beam.

From the perspective of the barrier beam drive function according to this invention it concerns: - the method of ensuring the lowering function of the barrier beam;

- the method of ensuring the securing function of the barrier beam in the upper end position;

- the method of ensuring the evaluation function of the barrier beam's end positions. The functional elements are arranged into three parallel branches the drive branch, the branch locking the barrier beam in the upper end position and the scanning and measuring branch. These branches are connected with the main shaft, to which the barrier beam is attached, through a mechanical gear. - The drive branch is comprised of the shaft of a DC motor - a driveshaft, which is connected to a mechanical gear through a coupling.

- The branch locking the barrier beam in the upper end position - it can also be called the braking branch - is comprised of two independent braking circuits. Each braking circuit is made up by an electrically set friction brake and a mechanical free engine clutch.

- The scanning and measurement branch is made up of a pair of non-contact electronic position sensors that are attached to the sensor and measurement shaft.

The doubling of the crucial functions and elements concerns - the lowering function,

- the function of securing the barrier beam in the upper position, and

- the function of evaluating the upper and lower end positions.

Lowering function: Gravitational lowering is supplemented with forced lowering - using a motor. It is important that the barrier beam's gravitational lowering ability is not affected and the drive remains a gravitational drive in the sense of the description above. The beam lowering ability cannot be negatively influenced even by extreme weather conditions. The high reliability of the lowering function is thereby achieved.

Function of securing the barrier beam in the upper end position: Each of the brake circuits is able to independently secure the barrier beam in the upper end position with its braking torque. The activity of the braking circuits is tested for functionality. After each lifting of the barrier beam to the upper end position one of the brake circuits is always interrupted for a short time and the function of the uninterrupted circuit is tested, which means it controls whether the braking torque is sufficient for securing the barrier beam in the upper end position. The functionality of the brake circuits is evaluated and indicated, which means that a failure in the brake circuit is indicated and reported to the operator. This ensures the fast repair of the malfunctioning brake circuit in time, when the second brake circuit is functional and so it leads to the vital function of the locking of the barrier beam in the upper end position.

Function of evaluating the barrier beam's upper and lower end positions: Two sensors constantly scan the direction angle of the main shaft bearing the barrier beam. To evaluate the end position (upper or lower) it is necessary for both sensors to report the relevant position at the same time. A state of disagreement is evaluated as a malfunction through the drive control circuits. This leads to the safe functionality of the evaluation of the barrier beam's end positions.

Description of the Figures

The mechanical relations between the functional parts of the barrier drive are drawn schematically in Fig.l. Block diagram of the control of the barrier drive is in Fig. 2.

Examples of Implementing the Invention

The shaft of the bidirectionally-rotating driving motor K), specifically a shunt motor, is connected to the first gear J_2 of the gear mechanism through a friction coupling U_. From here its movement leads through the second gear H of the second gear mechanism to the main driveshaft I. At the same time, the second gear B. is connected to the braking shaft J_6 through two free engine clutches 9, 9\ Two independent electric friction brakes 7, 8 functioning as locking elements are arranged on the braking shaft 16. Each brake circuit is comprised of electrically set friction brakes 7, 8. The first brake circuit contains the first brake 7 and the second brake circuit contains the second brake 8. The revolving movement of the main driveshaft I is transferred to the sensor and measurement shaft J_5, through the third scanning gear H, comprised of gear wheels with direct gearing. Two angle sensors 2, 3 of an optoelectronic construction are attached to the sensor and measurement shaft J_5. The first angle sensor 2 of the main driveshaft's position and the second angle sensor 3 of the main driveshaft's position are electronically connected to the control unit 6. Command signals 4 are transmitted to the control unit 6, which also ensures the control of the driving motor K) and there are simultaneously command signals 4 transmitted to the first brake 7 of the first brake circuit and to the second brake 8 of the second brake circuit. Both brakes 7, 8 are mechanically connected with the free engine clutch connections 9 and 9'.

When it is necessary to raise the barrier, the control unit 6 issues a command to the motor JO, which starts to revolve, on the basis of the vital command signal 4 from the level crossing signalling equipment (not depicted) and on the basis of information on the barrier beam's position, received simultaneously from both angle sensors 2, 3. The motor's 10 revolutions are electronically regulated so that the lifting of the barrier beam takes place in a set interval and simultaneously so that the starting torque when the barrier beam starts to rise is as high as possible and the running down to the upper end position is fluent, without any impact to the drive's mechanical parts.

From the perspective of regulation the lifting is thus divided into multiple selectable regulatory areas. To limit the current impulse during the motor's K) starting torque the control unit 6 makes it possible to set the start of the lifting so that the individual barrier drives at the railway crossing begin lifting with a short time interval. The command to raise the barrier beam also leads to a locking of the brakes 7, 8 in both brake circuits. Each brake circuit is able to independently lock the barrier beam in the upper end position.

The movement of the barrier beam during lifting is enabled by the rotation of the free engine clutches 9, 9'. The movement of the motor shaft JjO is transferred to the main driveshaft I through the coupling JJ_ and gears 12 and 13. Both sensors 2, 3 evaluate the driving main shaft's J _. movement and as soon as it reaches the end position, where the barrier beam is in the upper end position, the control unit 6 issues a command to stop the motor JO. Vital information 5 on the upper end position of the barrier beam is only given to the level crossing signalling equipment in the event, that both of the angle sensors 2, 3 evaluated this position at the same moment in time. The level crossing signalling equipment issues a vital command to test the functionality of the brake circuit on the basis of the vital information 5 on the upper end position of the barrier beam. This alternates after each lifting, i.e. regularly and automatically, so that after one lifting of the barrier beam, the circuit of the second brake 8 is interrupted for a period of 3 - 5 seconds, and the ability to lock the barrier beam in the upper end position by the first brake 7 is monitored. After the next lifting the circuit of the first brake 7 is interrupted for the same period of time, and the ability to lock the barrier beam in the upper end position by the second brake 8 is monitored. The insufficient ability of either of the brakes 7, 8 is detected by a loss of vital information 5 on the upper end position. A lifting command (the barrier beam is drawn up by the motor H)) is reissued on the basis of this information 5 and the test is also immediately interrupted. A negative test result is reported to the operator and equipment maintenance, which repairs the brake circuit. Until the repairs are carried out the barrier beam is locked by the functional brake circuit. This achieves the safe locking functionality of the barrier beam in the upper end position.

In the event that it is necessary to lower the barrier beam, the brake circuits 7, 8 are interrupted on the basis of a vital command from the level crossing signalling equipment. This initiates the gravitational lowering. At the same moment the control unit 6 issues a command to the motor K) for the opposite, reverse movement on the basis of this command and on the basis of information on the position of the barrier beam from the angle sensors 2, 3, which results in the initiation of the forced lowering by the motor. The movement of the shaft of the motor JjO is transferred in the aforementioned method to the main shaft L At the same time both sensors 2, 3 evaluate the movement of the main shaft 1. The motor's revolutions are electronically regulated so that the lowering of the barrier beam takes place in a set interval of 5 - 10 seconds.

From the perspective of regulation the lowering is divided into multiple selectable regulatory areas. After achieving the previously-set selectable angle of the barrier beam the power supply for the motor armature circuit is switched off, and the armature circuit is bridged by a dynamically-changing load, which enables the lower end position to be reached fluidly. Information 5 on the barrier beam's lower end position is only given to the level crossing signalling equipment in the event that both of the angle sensors 2, 3 evaluated this position at the same moment in time.

The barrier's drive is equipped with diagnostics and the archival of recorded diagnostics data. As soon as there is a malfunction in any phase of the barrier beam's movement, e.g. to a power failure, the control unit does not receive an identical signal from both sensors 2, 3. A warning signal is sent to the equipment operator.

Industrial Applicability

The invention is suitable for the control of mechanical warnings on railroad crossings.