Patent Application
20080029348
Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention given as non-restrictive examples only and represented in the accompanying drawings, in which:
In
The brakes F1 and F1′, the hydraulic pipes 11 and 11′, and the hydraulic circuits 12 and 12′ constitute a first braking means 16 and a second braking means 16′ respectively. The braking means 16,16′, the control unit 14 which will be described in detail further on, and the speed sensor 13, constitute a braking unit of an aerial ropeway installation which is housed in a drive terminal in which the driving-pulley Po is located.
Only the hydraulic circuit 12 actuating the brake F1 is described in the following with reference to
An accumulator 26 is connected to a point 27 of the main circuit 18, intermediate between the check valve 19 and the pressure control switch 20. The accumulator 26 is also connected to the tank 25 by a first secondary circuit 28 comprising a drain valve 29 of the accumulator 26.
The outlet 17 is further connected to the tank 25 by a second secondary circuit 30 comprising in series a pressure gauge 31, a check valve 32, a three-channel manual distributor 33 and a hand pump 34. The distributor 33 is able to occupy three selective-control switching positions. In one of these positions, the distributor 33 establishes communication of the tank 25 with a point 35 of the first secondary circuit 28 intermediate between the drain valve 29 and the accumulator 26 by means of a pipe 36 comprising a check valve 37. The other two switching positions establish or do not establish feed of fluid under pressure from the hand pump 34 to the outlet 17.
A third, fourth, and fifth secondary circuits, bearing the respective reference numbers 38, 39, 40, connect the tank 25 and respective points of the main circuit 18 situated between the manual isolation distributor 23 and the solenoid feed valve 22. These points bear the respective reference numbers 41, 42, 43 for the secondary circuits 38, 39, 40 and are respectively arranged along the main circuit 18 going from the solenoid feed valve 22 to the manual isolation distributor 23. The third and fourth secondary circuits 38, 39 both comprise a solenoid safety valve, bearing the respective reference numbers 44 and 45. Moreover, the fifth secondary circuit 40 comprises in series a pressure sensor 46 and a solenoid discharge valve 47.
As illustrated in
In like manner for the second braking means 16′, the acquisition signal S1 is also transmitted, in the control unit 14, to a second comparator 51 generating a second differential signal S7 representative of the difference between the acquisition signal S1 and a second setpoint signal S8 representative of the instantaneous value of a second predetermined deceleration setpoint curve C2 (
The parameters of the correctors 49 and 52 are chosen such as to obtain a suitable response of the method and of the regulation, the objective being to be robust, fast and precise, and to limit overshoots, which enables the influence of external conditions such as temperature being able to be ignored.
Moreover, the acquisition signal S1 is transmitted to a third comparator 54 generating a third differential signal S12 representative of the difference between the acquisition signal S1 and a command signal S13 representative of the instantaneous value of a predetermined deceleration control curve C3 (
The first differential signal S2 output from the first comparator 48 is further transmitted to a third input of the third management unit 57. The acquisition signal S1 is also transmitted to a fourth input of the third management unit 57. According to the differential signals S1, S2, S12 and to the signal from the timer T, the third management unit 57 is able to generate a first closing command signal S14 of the solenoid safety valves 44′ and 45′ of the hydraulic circuit 12′ of the second braking means 16′. The first closing command signal S14 is also transmitted to the second management unit 53. The third comparator 54, the third management unit 57, the timer T, and the electrical connections conveying the signals S1, S2 and S12 to S14 constitute a first emergency stop circuit 58, operation whereof will be dealt with in detail further on.
In the control unit 14, the acquisition signal S1 is also transmitted to an input of a fourth management unit 59, the other input whereof is connected to the output of the timer T. Depending on the signals received, the fourth management unit 59 is able to generate a second closing command signal S15 of the solenoid safety valves 44 and 45 of the hydraulic circuit 12 of the first braking means 16. The second opening command signal S15 is also transmitted to the first management unit 50. The fourth management unit 59, the timer T, and the electrical connections conveying the signals S1 and S15 constitute a second emergency stop circuit 60 the operation whereof will be dealt with in detail further on.
In addition, the management units 57, 59 deliver the closing command signals S14 and S15 when the acquisition signal S1 is representative of a running speed of the rope that is lower than or equal to a preset value K.
In an alternative embodiment of the invention, the braking unit comprises two distinct speed sensors 13. One of the sensors 13 is then connected to the first modulation circuit 55 and the other of the sensors 13 is connected to the second modulation circuit 56. Such a structure guarantees that each braking means 16, 16′ has its own electrical power supply. Thus, in the event of an electrical failure, only the mechanical brake F1, F1′ of the braking means 16, 16′ whose electrical power supply has failed is commanded to its maximum braking position to prevent too sharp braking of the rope which would be liable to cause derailment of the rope from its guiding means, in particular at the level of the rollers of guide pulley array. The management units 50, 53, 57, 59 can nevertheless be grouped in a unitary management unit such as a programmable controller.
As illustrated in
The second deceleration setpoint curve C2 is made up of a first section of horizontal line passing through a point noted A2 with abscissa t0 and ordinate greater than Vn. More precisely, the difference between the ordinate of the point A2 and Vn is noted V2f. The end point of the horizontal section is noted D2. The abscissa of the point D2 is greater than t0 and its ordinate is equal to that of the point A2. The difference between the abscissa of the point D2 and t0 is noted t2f. The horizontal section is extended by a descending straight line section cutting the x-axis at a point B2 intercalated between the points B1 and B5. The difference of abscissa between the points B2 and B1 is noted Δt.
Consequently, the instantaneous value of the second deceleration setpoint curve C2 is greater than the instantaneous value of the first deceleration setpoint curve C1 at each time of reading. On a first part of the second deceleration setpoint curve C2 on the other hand, its value is greater than the instantaneous value of the curve C5 at each time of reading. But on the remaining part of the curve C2, its instantaneous value is lower than the instantaneous value of the curve C5 at each time of reading. Consequently, the second setpoint curve C2 is determined to correspond to a stopping time required for the installation that is lower than the regulatory maximum limit value.
The control curve C3 is for its part made up of a first section of horizontal line passing through a point noted A3 of abscissa t0 and ordinate greater than Vn. More precisely, the difference between the ordinate of the point A3 and Vn is noted Vtag. The end point of the horizontal section is noted D3. The abscissa of the point D3 is greater than t0 and its ordinate is equal to that of the point A3. The difference between the abscissa of the point D3 and t0 is noted ttag. The value of ttag is greater than t2f. The horizontal section is extended by a descending straight line section cutting the x-axis at the point B5.
The instantaneous value of the second control curve C3 is consequently greater than the instantaneous value of the second deceleration setpoint curve C2 at each time of reading.
The values of Vtag, V2f, t2f, ttag, Δt are parameters internal to the control unit and can be modified by means of a man-machine interface that is not represented. Any correction made to the value of these parameters modifies the profile of the curves C1, C2 and C3 concerned by said correction accordingly. The modifications made to the curves are automatically recorded in the control unit memory.
The braking unit operates in the following manner:
In normal operation of the installation, the first management unit 50 transmits the first opening command signal S5 to the solenoid feed valve 22. Likewise, the second management unit 53 transmits the third opening command signal S10 to the solenoid feed valve 22′. As the solenoid feed valves 22, 22′ are of the “open-fed” type, they are then open. The solenoid discharge valves 47, 47′ are on the other hand closed. The third management unit 57 transmits the first closing command signal S14 to the solenoid safety valves 44′, 45′ and to the second management unit 53. The fourth management unit 59 transmits the second closing command signal S15 to the solenoid safety valves 44, 45 and to the first management unit 50. The solenoid safety valves 44, 45, 44′, 45′ are therefore closed. The hydraulic circuits 12, 12′ are under pressure. The oil under pressure comes from the accumulators 26, 26′. The manual isolation distributors 23, 23′ are open and the pipes 11, 11′ are under pressure. The mechanical brakes F1, F1′ are therefore released. The check valves 32, 32′ are closed. The running speed of the rope is equal to the nominal speed Vn.
According to an independent functioning of the actions which will be described further on in the present, the oil pressure in the accumulators 26, 26′ is continually maintained to be comprised between a high threshold and a low threshold, whether it be in stabilized operating conditions of the installation or during braking. When the pressure in a circuit 12, 12′ reaches the low threshold (for example 102 bars), the corresponding pressure control switch 20, 20′ triggers start-up of the associated pump P, P′. By suction from the tank 25, the pump P, P′ in operation discharges the oil under pressure to the associated accumulator 26, 26′ and to the associated solenoid feed valve 22, 22′, regardless of the state of said solenoid feed valve 22, 22′. When the pressure in the circuit 12, 12′ reaches the high threshold (for example 110 bars) on the other hand, the corresponding pressure control switch 20, 20′ commands shutdown of the associated pump P, P′. In case of malfunctioning of the pressure control switch 20, 20′ at the moment the high threshold is detected, the associated pressure relief valve 61, 61′, which is calibrated to a preset value (for example 116 bars), opens and the excess oil returns directly to the tank 25. After a pre-programmed time, the control unit 14 automatically performs stopping of the pump P, P′ which is running. Furthermore, in case of malfunctioning of a pump P, P′, it is possible to actuate the associated hand pump 34, 34′. The three-channel manual distributor 33, 33′ is then commanded to the position selecting communication between the hand pump 34, 34′ and the pipe 36. By suction from the tank 25, the oil thus pumped tops up the oil level in the accumulator 26, 26′ and in the associated hydraulic circuit 12, 12′.
A braking order OF transmitted by the control means and/or the detectors 15 to the control unit 14 causes the traction of the electric motor M to be interrupted and activates the management units 50, 53, 57, 59. The first management unit 50 sends back the second opening command signal S6 to the solenoid discharge valve 47. As the latter is of the “open-fed” type, the solenoid discharge valve 47 opens and the oil under pressure is removed to the tank 25 via the fifth secondary circuit 40. At the same time, the first management unit 50 stops transmitting the first opening command signal S5 and the solenoid feed valve 22 closes. The oil pressure in the main circuit 18 and in the pipe 11 decreases. The mechanical brake F1 closes progressively under the action of the spring and the jaws come into contact with the driving-pulley Po. Furthermore, activation of the second management unit 53 by the braking order OF in return causes transmission of the fourth opening command signal S11 to the solenoid discharge valve 47′. As the latter is of the “open-fed” type, the solenoid discharge valve 47′ opens and the oil under pressure is removed to the tank 25 via the fifth secondary circuit 40′. At the same time, the second management unit 53 stops transmitting the third opening command signal S10 to the solenoid feed valve 22′. The oil pressure in the main circuit 18′ and in the pipe 11′ decreases. The mechanical brake F1′ closes progressively under the action of the spring and the jaws come into contact with the driving-pulley Po.
The value of the contact pressure of the jaws of the mechanical brakes F1, F1′ is adjusted by the hydraulic pressure indicated by the pressure sensors 46, 46′. The brakes therefore move towards the driving-pulley Po with maximum celerity. The approach time is extremely small (considered as negligible in the explanations of
Receipt of the braking order OF also activates the timer T which in return triggers the preset time delay during which the timer T does not transmit any signal to the third and fourth management units 57 and 59.
At the moment the oil pressure in the fifth secondary circuits 40, 40′ reaches the pressure value indicated by the pressure sensors 46, 46′, the management units 50, 53 and 57 trigger activation and simultaneous reading of the deceleration setpoint curves C1 and C2 and of the control curve C3 which are stored in the memory of the control unit 14. During the remaining part of the braking operation, the instantaneous value of the curves C1 to C3 determined at each moment by reading of the memory is translated, in real time, into a representative signal. The first and second setpoint signals S3 and S8 are thus, at all times, representative respectively of the instantaneous values of the deceleration setpoint curves C1 and C2. In like manner, the command signal S13 is, at all times, representative of the control curve C3.
In parallel with the operations of the previous paragraph, the first comparator 48 establishes in real time the difference between the acquisition signal S1 coming from the speed sensor 13 and the first setpoint signal S3. The first corrected signal S4 on output from the corrector 49 is at all times directly representative of the first differential signal S2. According to the signal S4, the first management unit 50 commands opening of the solenoid discharge valve 47 and of the solenoid feed valve 22. In parallel, the second comparator 51 establishes in real time the difference between the acquisition signal S1 and the second setpoint signal S8. The second corrected signal S9 on output from the corrector 52 is at all times directly representative of the second differential signal S7. According to the signal S9, the second management unit 53 commands opening of the solenoid discharge valve 47′ and of the solenoid feed valve 22′.
More precisely, as the first deceleration setpoint curve C1 is a descending straight line, the first corrected signal S4 tends to increase because the contact pressure of the jaws of the brake F1 does not then enable a sufficient braking force to be provided. Consequently, the first management unit 50 continues transmitting the second opening command signal S6 to the solenoid discharge valve 47, which therefore continues to be open. The oil pressure in the main circuit 18 and in the pipe 11 is still decreasing and the mechanical brake F1 closes progressively. The braking force continues to increase and the running speed of the rope decreases.
If the deceleration is or becomes too great, the first management unit 50 transmits the first opening command signal S5 to the solenoid feed valve 22 and stops transmitting the second opening command signal S6 to the solenoid discharge valve 47. The liquid of the accumulator 26 feeds the hydraulic circuit 12 tending to increase the pressure in the circuit and to open the brake F1. Slowing-down of the rope decreases and as soon as the deceleration reverts to the normal value on the corresponding curve, the first management unit 50 commands closing of the solenoid feed valve 22 and opening of the solenoid discharge valve 47. By suitable management of transmission of the signals S5 and S6 by the first management unit 50, the first modulation circuit 55 thereby performs automatic regulation of the braking action generated by F1, and consequently of the running speed of the rope, according to the first deceleration setpoint curve C1.
As far as the second braking means 16′ are concerned, at the moment the oil pressure in the fifth secondary circuit 40′ reaches the pressure value indicated by the pressure sensors 46′, the management unit 53 stops transmitting the signals S10 and S11 so as to close the solenoid feed valve 22′ and the solenoid discharge valve 47′. The contact pressure of the jaws of the brake F1′ stabilizes. As the instantaneous value of the second setpoint curve C2 is at all times greater than the value of the first setpoint curve C1, the second differential signal S7 remains very high (in absolute value), because the running speed of the rope changes according to the automatic regulation described in the previous paragraph. As the second modulation circuit 56 performs an automatic regulation of the braking action generated by F1′, and consequently of the running speed of the rope, according to the second deceleration setpoint curve C2, the second braking means 16′ and the second modulation circuit 56 are kept in the contact configuration generating a negligible braking force.
At the same time, at the moment when receipt of the first emergency stop signal S14 by the second management unit 53 is interrupted, the management unit 53 commands opening of the solenoid discharge valve 47′ to intensify the pressure drop. For the same purpose, at the moment when receipt of the second closing command signal S15 by the first management unit 50 is interrupted, the management unit 50 commands opening of the solenoid discharge valve 47 and closing of the solenoid feed valve 22. These operations performed by the emergency stop circuits 58 and 60 enable direct braking to be applied by the braking means 16, 16′, by stopping the modulations performed up to then by the modulation circuits 55 and 56, so as to guarantee that the rope is kept well in the stopped state and in particular to prevent the rope being driven by the gravity of the vehicles coupled thereon. The direct braking time can be ignored on account of the low value of K. Moreover, this direct braking is only optional for it is possible to provide for the modulation performed by the first modulation circuit 55 to be really performed until the rope is completely stopped.
In an embodiment of the modulation and the regulation performed by the second modulation circuit 56, when the second differential signal S7 reaches a first preset positive value internal to the second management unit 53, which corresponds in this example to the time when the difference between the running speed of the rope and the setpoint curve C2 becomes greater than a preset positive value, the second management unit 53 transmits the fourth opening command signal S11 to the solenoid discharge valve 47′ which opens. The oil pressure in the main circuit 18′ and in the pipe 11′ decreases and the mechanical brake F1′ closes progressively. The braking force increases and the running speed of the rope decreases more strongly.
When the second differential signal S7 reaches a preset second negative value internal to the second management unit 53, which corresponds in this example to the time when the difference between the running speed of the rope and the setpoint curve C2 becomes lower than a preset negative value, the second management unit 53 transmits the third opening command signal S10 to the solenoid discharge valve 22′ and stops transmitting the fourth opening command signal S11 to the solenoid discharge valve 47′. The liquid of the accumulator 26′ feeds the hydraulic circuit 12′ tending to increase the pressure in the circuit and to open the brake F1′. Slowing-down of the rope decreases and as soon as the deceleration reverts to the normal value on the corresponding deceleration curve, the second management unit 53 again commands closing of the solenoid feed valve 22′ and opening of the solenoid discharge valve 47′. The curve of the change in time of the running speed of the rope oscillates around the second deceleration setpoint curve C2 during the second part of braking until the preset value K is reached. At this stage, as before, the management units 57 and 59 stop transmitting the closing command signals S14 and S15 to the solenoid safety valves 44, 45, 44′, 45′ and to the management units 50 and 53.
It is possible to provide other embodiments of the modulation and the regulation performed by the second modulation circuit 56, in which the control unit 14 commands opening of the solenoid discharge valve 47′ before the speed of the rope exceeds the second deceleration setpoint curve C2. In this case, the second management unit 53 can perform modulation of the opening command signals S10 and S11 enabling simultaneous transmission of the two signals S10 and S11. This possible operating mode enables the pressure drop in the hydraulic pipe 11′ to be modulated.
This step is illustrated in
An external releasing order of the brakes F1, F1′ received by the control unit 14 after the installation has been stopped causes start-up of the pumps P, P′ and recharging of the hydraulic circuits 12, 12′, the pipes 11, 11′ and the accumulators 26, 26′. In case of maintenance, closing the manual isolation distributor 23, 23′ enables the pipe 11, 11′ to be isolated and the brake F1, F1′ to be kept in the open position. In this case, the pressure in the pipe 11, 11′ can be established by the hand pump 34, 34′ by means of the second secondary circuit 30, 30′. Moreover, the drain valve 29, 29′, in the open position, enables the liquid contained in the corresponding accumulator to be removed to the tank 25.
In all the previously described braking cases, the management units 57 and 59 stop transmitting the closing command signals S14 and S15 if the acquisition signal S1 is representative of a rope running speed greater than zero after the preset time delay triggered by automatic activation of the timer T caused by receipt of the braking order OF.
Absence of transmission of the first closing command signal S14 by the third management unit 57 can be assimilated to delivery of a first emergency stop signal by the first emergency stop circuit 58. On the contrary, transmission of the first closing command signal S14 can be assimilated to the absence of generation of the first emergency stop signal by the first emergency stop circuit 58. In similar manner, absence of transmission of the second closing command signal S15 by the fourth management unit 59 can be assimilated to delivery of a second emergency stop signal by the second emergency stop circuit 60. On the contrary, transmission of the second closing command signal S15 can be assimilated to the absence of generation of the second emergency stop signal by the second emergency stop circuit 60. More precisely, it can be considered that the first and second emergency stop signals are generated by the third and fourth management units 57, 59 respectively. In other alternative embodiments of a braking unit where the solenoid safety valves 44, 45, 44′, 45′ are of the “open-fed” type, the first and second closing command signals S14 and S15 directly constitute the first and second emergency stop signals respectively.
By suitable management of transmission of the signals S5, S6, S10, S11 by the management units 50 and 53, the modulation circuits 55, 56 each perform a regulation of the braking action generated by the associated mechanical brake F1, F1′, and consequently of the running speed of the rope, according to the corresponding deceleration setpoint curve C1, C2. The basic principle for each of these two regulations is to measure the difference between the actual speed of the rope and the value sought for (setpoint curves C1 or C2), and to operate the mechanical brakes F1, F1′ acting on the actual speed to reduce this difference by a suitable modulation of the setpoint signals S5, S6, S10, S11 which command the hydraulic circuits 12, 12′ actuating the brakes F1, F1′.
One or the other of the first and second braking means 16, 16′ can consist of an electromagnetic brake provided on the high-speed output shaft GV and controlled by the control unit 14, without this alternative embodiment departing from the scope of the invention. Moreover, the invention can be applied to any rope transport installation implementing a braking unit provided with two distinct braking means each having a mechanical brake for slowing down running of the rope and an actuating circuit of the brake, with a speed sensor delivering an acquisition signal representative of the running speed of the rope, and with a control unit able to transmit command signals to the actuating circuits of the braking means, such as for example a chairlift or gondola car/cabin installation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06 07174 | Aug 2006 | FR | national |
