CA2150964A1 - Elevator control systems - Google Patents
Elevator control systemsInfo
- Publication number
- CA2150964A1 CA2150964A1 CA 2150964 CA2150964A CA2150964A1 CA 2150964 A1 CA2150964 A1 CA 2150964A1 CA 2150964 CA2150964 CA 2150964 CA 2150964 A CA2150964 A CA 2150964A CA 2150964 A1 CA2150964 A1 CA 2150964A1
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- floor
- elevator
- latch
- latching
- car
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Abstract
An elevator control apparatus is intended for an elevator having a car and at least one intermediate floor between top and bottom floors thereof. The apparatus includes an upper proximity switch and a lower proximity switch mounted on the car and vertically spaced-apart from each other. There is a vane at each floor for activating the upper proximity switch and the lower proximity switch to produce first and second signals respectively as the proximity switches move adjacent said vanes. There are up latches for each said intermediate floor for changing a state when the first signal is produced and the elevator moves downwardly past each intermediate floor and when the first signal is produced and the elevator is moving upwardly towards each intermediate floor. There is a down latch for each intermediate floor for changing a state when the second signal is produced and the elevator moves upwardly past each intermediate floor and when the second signal is produced and the elevator moves downwardly towards each intermediate floor. Controls are connected to the latches for controlling the elevator movement according to which latches are latched and unlatched. Preferably the latches are operatively inter-connected so only one said latch is latched or unlatched as each signal is produced. The proximity switches may be connected to a car levelling system which levels the car at each floor. Alternatively, the proximity switches may be connected to a car slow down system.
Description
_ ELEVATOR CONTROL SYSTEMS
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to elevator control systems and, more particularly, to control systems for use with elevators in multi-story buildings.
Description of the Related Art Various control systems have, in the past, have been used for the stopping of elevator cars at any of a plurality of different floors in a multi-story building.
15 Prior art elevator control systems have normally employed a selector system for determining whether at any instant, the elevator car is located above, below or at any particular floor and, therefore, whether the elevator car is required to travel upwardly or downwardly, or to remain stationary, in order to answer a pending call.
20 Examples of conventional selector systems include the following:
1. A floor switch, at an intermediate floor, is operated by a two lane cam mounted on the elevator cab, from either an up-position or a down-position to a center-position, when the elevator reaches the floor, and to the opposite side, as the elevator passes the floor.
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to elevator control systems and, more particularly, to control systems for use with elevators in multi-story buildings.
Description of the Related Art Various control systems have, in the past, have been used for the stopping of elevator cars at any of a plurality of different floors in a multi-story building.
15 Prior art elevator control systems have normally employed a selector system for determining whether at any instant, the elevator car is located above, below or at any particular floor and, therefore, whether the elevator car is required to travel upwardly or downwardly, or to remain stationary, in order to answer a pending call.
20 Examples of conventional selector systems include the following:
1. A floor switch, at an intermediate floor, is operated by a two lane cam mounted on the elevator cab, from either an up-position or a down-position to a center-position, when the elevator reaches the floor, and to the opposite side, as the elevator passes the floor.
2. A selector, driven by a tape or cable or cable attached to a car and/or to a co~~ veight located in a m~rhine room contains a plurality of contacts for controlling the operation of the elevator to the floors and in the vicinities of the floors.
30 3. A relay-operated selector system is operated by intermittent floor switches mounted in proximity to the intermediate floors.
4. A relay-operated selector system is operated by intermediate floor switches mounted on the elevator car and actuated by vanes in different lanes at the intermediate floors.
s 5. A magnetic tape is employed to operate a microprocessor.
All of the above-described prior art systems require components of one type or another to be installed in the hoistway or in the machine room in order to register the location of the elevator 10 car in the hoistway, together with the required wiring, in addition to the hoistway limit switches, slowdown-, levelling- and door-zone contacts and switches, all of which are already employed on 2-landing elevators.
Slowdown- and levelling-contacts and switches are employed to slow the motion of the elevator 15 car as it reaches a selected floor, at which it stops, and also to keep the elevator car level with that selected floor until the elevator car moves away to a different floor.
It is, however, a disadvantage of the prior selector systems that, since they employ separate contacts or switches for regi~t~ring the movement of the elevator car past the building floors, on 20 one hand, and for levelling the elevator car relative to any floor at which the car is stopped, on the other hand, the costs of components, in~t~ tion and m~int~n:~nce are correspondingly high, and the reliability of the system, which is dependent on the number of components employed, is correspondingly degraded.
BRIEF SUMMARY OF THE INVENTION
It is, accordingly, an object of the present invention to provide a novel and improved elevator control system which employs a single set of switches for the dual purposes of registering the travel of the elevator car as it passes the floors of a multi-story building and for another purpose -such as levelling the elevator near any floors or slowing the elevator as it approaches a floor.
According to the invention there is provided an a~pald~us for controlling an elevator in a building having at least one intermediate floor between a top floor and a bottom floor thereof.
5 The apparatus includes first ~ign~lling means, for each said intermediate floor, for ~ign~lling a first signal when the elevator moves above said each intermediate floor. There is second si~;n~lling means, for said each intermediate floor, for sign~lling a second signal when the elevator moves below said each intermediate floor. Latching means for each said intermediate floor is operatively connected to the sign:~lling means for ch~ngin~ a latch state when the first 10 and second signals are received by the latch means. There is also means operatively connected to the latch means for controlling movement of the elevator depending upon the state of said each latch means.
The first ~i~n~lling means and the second ~i n~lling means may include vertically spaced-apart 15 first and second proximity switches on the elevator car and a stationary activating means at said each intermediate floor positioned for activating said each proximity switch as they move past said each activating means. For example, the proximity switches may be levelling switches or slow down switches for the elevator.
20 The latching means may include an up latch for each intermediate floor operatively connected to said each first ~i~n:~lling means and a down latch for each intermediate floor operatively connected to each said second ~ign~llin~ means. There is up direction indicating means for indicating when the elevator is moving up and down direction indicating means for indicating when the elevator is moving down. The up latch and the down direction ~ign~lling means are 25 operatively connected so each up latch is latched as the elevator moves down past said each intermediate floor. The down latch and the up direction indicating means are operatively connected so each down latch is latched as the elevator moves up past said each intermediate floor.
The l~tçhinE means may include up lml~t(~hing means for lml~tçhing each said up latch and down unlatching means for llnl~trhinE each said down latch. The up nnl~tçhing means is operatively connected to the up direction indicating means, whereby each said up latch is unlatched when the elevator moves up and approaches said each intermediate floor. The down unlatching means 5 is operatively connected to the down direction indicating means, whereby each said down latch is unlatched when the elevator moves down and approaches each said intermediate floor.
The up latch for each said floor and the means for unlatching thereof are preferably each connected to a contact opened by the unlatching means of a floor immediately below said each 10 floor. The down latch of each said floor and the means for unlatching thereof are preferably each connected to a contact opened by the unlatching means of a floor immediately above said each floor. Thus the ~i~n~llinE means latches or unlatches only one said l:~t~hing means with each said signal.
15 Another aspect of the invention provides a method for controlling movement of an elevator as required by a call system towards a selected floor. The elevator has a car with a pair of vertically spaced-apart, upper and lower proximity switches and means at each floor for actuating each said proximity switch. The method includes connecting each proximity switch to a digital processor.
The processor is programmed with software including up l~tçhinE means for each of a plurality 20 of floors, for latching when the upper proximity switch is actuated and the elevator is moving downwardly away from or past each said floor and for llnl~tchinE when the first proximity switch is actuated and the elevator is moving upwardly towards said each floor. The software also includes down latching means for said each floor for l~t~hinE when the second signal is produced and the elevator is moving upwardly away from or past said each floor and for unlatching when 25 the down proximity switch is actuated and the elevator is moving downwardly towards said each floor. The processor is connected to the call system so the latching means and unlatching means direct the elevator towards the floor required by the call system.
Thus, with the present elevator control system, a single set of proximity switches, mounted on the car, can be utilized both for the registration of the passage of the elevator car past the building floors, and also for levelling the elevator car at the building floors or a similar function such as slowing down of the elevator near floors.
5 Consequently, the number of components of the system is reduced, and the reliability of the operation of the system is correspondingly increased, as compared with the above-discussed prior art systems. Also, the initial installation costs, the m~t~ri:~l costs and the m~inten:~nce costs are correspondingly reduced as compared with the prior art systems. Furthermore the need for a levelling adju~tm~nt to compensate for the settling of the building as it ages may be avoided.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects, features and advantages of the present invention will be more readily apparent to those skilled in the art from the following description of an elevator control system according 15 to the present invention, when taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a diagrammatic side elevation of an elevator and control system therefor according to an embodiment of the invention;
Fig. 2 is a block diagram of the control system thereof, Fig. 3a is a schematic ladder diagram of the contacts connected to the latching and unlatching relays of the control system;
Fig. 3b is a continll~tion of Fig. 3a; and Fig. 4 is a sçhem~tic diagram of the contacts, including contacts controlled by the l~tçhing relays, which are connected to the down direction and up direction relays for the elevator control system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, Fig. 1 illustrates a building shown generally at 15 which has four floors numbered 1, 2, 3, and 4 respectively. There is an elevator shown generally at 17 having 5 a car 19 capable of vertical movement between the floors. The elevator is equipped with five proximity switches in this example, proximity switch 12 being the up slow down switch which slows the car down when approaching a floor from below. Switch 16 is an up levelling switch which brings the elevator car up into position at the floor and will re-level it if it drops slightly below the floor when parked there, for example if a large load is added or due to hydraulic 10 sinking. Switch 20 is a door zone switch indicating that the elevator car is adjacent the door of a floor. Switch 18 is a down levelling switch which brings the elevator car down into position at the floor and re-levels it if the elevator moves slightly above the floor due to a change in the load. Switch 14 is a down slow down switch which slows the elevator car as it approaches a floor from above. Each of these switches is actuated by a vane for each floor, namely vanes 8, 9, 10 and 1 1 for floors 4, 3, 2 and 1 respectively. Each of the proximity switches provides a signal when the switch moves into position adjacent to one of the vanes. As described thus far, the arrangement is conventional for many elevators.
Conventional elevators include a different system for directing an elevator in the correct 20 direction towards a floor when a call button is pushed, either on the elevator or on the floor concerned. The present invention departs from such prior art elevators by lltili7ing the proximity switches described above in the floor selector system. All of the proximity switches are connected to a microprocessor 22 as shown schematically in Fig. 1. In this particular example the microprocessor is a Programmable Controller of a type commonly used in elevators. A
25 Series One or a Series One Plus Programmable Logic Controller (PLC) is used in this example.
In this preferred example of the invention all of the modifications to the equipment are carried out by way of software modifications to the PLC which can be carried out by someone skilled in the art with the aid of the disclosure herein. The invention can be best understood by explaining the functions of the components in terms of hardware such as relays, contacts and electrical connections as set forth below. However, these can be readily converted into appropliate software and such PLC's conventionally provide printouts of the programmed software in terms of combinations of relays and contacts. In fact, Fig.3 and 4 represent printouts from such a programmed PLC. The nurnbers shown in these figures refer to software functions 5 equivalent to relays as identified below:
PLC FUNCTIONS:
RELAY FUNCTION
160 First Floor Hall Call 161 2nd Floor Hall Call 162 3rd Floor Hall Call 163 Top Floor Hall Call 164 First Floor Car Call 165 2nd Floor Car Call 166 3rd Floor Car Call 167 Top Floor Call 170 Up Levelling Relay 171 DoorZoneRelay 172 Down Levelling Relay 173 Inspection Toggle SW
174 Run Relay Input 175 Insp. Up Toggle SW
176 Insp. Down Toggle SW
177 Key Switch 1. Main Control 200 Down Valve Output (or Down Pilot Relay) 201 Up Pilot Relay 202 Running Relay 203 Key Switch 2. Special Function _ 204 Down Direction Relay 205 Up Direction Relay 210 Upper Selector Protection Relay 211 Lower Selector Protection Relay 340 First Floor Down Selector Relay 341 2nd Floor Up Selector Relay 342 2nd Floor Down Selector Relay 343 3rd Floor Up Selector Relay 344 3rd Floor Down Selector Relay 345 Top Floor Up Selector Relay Referring to Fig. 3, this shows the contacts connected in series which must be closed in order to latch or unlatch (also referred to "set" or "reset") the floor selector relays 340,341, 342, 343,344 and 345. Each of these relays is a latching relay with two coils, one for l~t~ hing the latching the 15 relay and one for l-nl~tchin~ it. In Fig.3, the contact must be closed to latch a relay followed by "(SET)" and the contacts which must be closed to unlatch the relay are followed by "(RST)".
The contacts marked "]["are open when unenergized, while contacts "]/[" are closed when unenergized.
20 The top floor 4 and the bottom floor 1 are special cases as described below. The intermediate floors 3 and 2 operate in the same manner. Each has two relays, the up relays l~tching as the elevator car leaves the floor in the down direction and unlatching when the car approaches the floor in the up direction. There is also a down relay for each floor which latches when the elevator leaves the floor in the up direction and unlatches when the elevator car approaches the 25 floor from above. The a~aldlus and method are described further in relation to a specific case where the elevator car leaves, for example, the third floor in the down direction. In this particular example the up relays and down relays are latched and unlatched by signals from up levelling switch 16 and down levelling switch 18 respectively. In other examples these relays could be actuated by signals from the up slow down switch 12 and down slow down switch 14, such as on multi-or variable speed applications. In this example the up levelling switch 16 is connected to up levelling relay 170, while down levelling switch 18 is connected to down levelling relay 172. These relays close the contacts 170 and 172 respectively shown in Fig. 3 when the switches approach the vanes 8, 9, 10 and 11. Likewise the door zone switch 20 is S connected to a door zone relay 171 to close the contacts 171 when switch 20 is adjacent the vane.
In some 2 speed installations the door zone relay is omitted because the switching must be done some distance, 3.5 feet in one example, before the elevator reaches the floor to have a long enough slow down speed zone. There are two sets of contacts 200 and 201 in this case. The contacts 200 are connected to a down valve output which indicates that the elevator car is moving downwards, while relay 201 is an up running pilot which indicates that the elevator car is moving up. Thus contacts 200 are closed when the elevator car moves down and contacts 201 are closed when the elevator moves up. (In other applications relay 200 and its contacts may be used as a down pilot relay in the same manner as relay 201 is used as an up pilot relay.) The contacts 340, 341, 342, 343, 344 and 345 are closed by the correspondingly numbered latching relays. In this example a 2 second timer Tl is connected in series with relay 200 as shown in Fig. 3b and a similar timer T2 in series with relay 201. These extend the up or down running signal for a slightly longer time than it takes the elevator to come to a sliding stop when operated on inspection. This could allow an up or down slow down switch to slide through a vane without the presence of the running signal, thus giving an incorrect floor count. The timed relays are de~i~n~ted 200T and 201T in Fig. 3a and the top of Fig. 3b.
Supposing the elevator car, for example, leaves the third floor in the down direction, this causes up levelling switch 16 to pass by vane 9 as the elevator leaves the floor. Thus a signal is provided to up levelling relay 170 which closes the corresponding contact 170 on the coil ofthird floor up selector relay 343. The down running relay 200 is closed since the elevator car is moving down and relay 171 is closed because the elevator car is still at the door zone. Contact 342 is closed because the second floor down selector 342 is still latched because the elevator car is above the floor and would move down to the second floor if called thereto. Contact 344 is a normally closed contact which is closed, indicating that third floor down selector relay 344 was -reset as proximity switch 18 passed by vane 9 as the elevator approaches the third floor the last time from above. Thus third floor up selector relay 343 is latched and will route all calls to this floor to the up direction relay 205 as shown in Fig. 4. Thus either the third floor hall call 162 or the third floor car call 166 are routed to up direction relay 205 via contacts of the third floor selector relay 343, down direction relay 204 and the rem~ining closed contacts which are not pertinent to this discussion.
A second contact from relay 343 in the reset coil circuit of second floor down selector relay 342 is closed when the relay 343 is latched. When the proximity switch 18 approaches vane 10 down 10 levelling relay 172 is closed along with its corresponding contact on the reset coil of relay 342.
Also the down running relay 200 is closed together with the normally closed contact 341 of the second floor up selector relay and the contact of the third floor up selector relay described above.
Thus second floor down selector relay 342 is unlatched in the moment when the door zone relay 171 is pulled in by its corresponding ploxi~ y switch 20 when it approaches vane 10 and closes 15 its contact 171 in the re-set circuit of relay 342. This means that second floor hall call 161 and second floor car call 165 no longer route calls to the down direction relay 204 as shown in Fig.
4. The second floor up selector 341 is not set until the elevator moves below the second floor.
Two normally closed contacts from the unlatched relays 341 and 342 indicate that the elevator is within the second floor zone and, if a call to the floor is registered, the elevator car will go into 20 low speed if so equipped, or when reaching the second floor vane 10 with the door zone switch 20, activates the door zone relay 171. The elevator car goes into ~lltom~tic levelling and will then stop at the level of the second floor.
As relay 342 is lml~t~lled, a 342 contact in the reset coil of the third floor up selector relay 343 25 is opened, thus disabling relay 343 from resetting when the up levelling relay 170 is activated as proximity switch 18 moves by vane 10 as the elevator car moves down to the first floor. In this manner, only one of the floor selector relays is set to be latched each time the proximity switch moves by one of the vanes.
If the elevator car continues to move down to the first floor, then second floor up selector relay 341 is latched in the same way as relay 343 wæ latched when the elevator car left the third floor in the down direction as described above. This locks out the reset circuit of the second floor down selector relay 342 and routes all calls to the second floor to the up direction relay 205 shown in Fig. 4. If the elevator car instead moves up, the second floor down selector relay 342 is set by the down levelling relay 172 connected to proximity switch 18 as it passes the second floor vane 10. A call to the second floor is now routed to the down direction relay 204 and the 342 contact in the 343 reset circuit closes so the relay 343 is unlatched when the up levelling switch and relay 170 are activated by the vane on the third floor.
The description of the above is typical for any intermediate floor on a multi floor building.
However the top floor and bottom floor are special cases. The first floor down selector relay 340 and the fourth up selector relay 345 are reverse operating, setting as the elevator reaches the first or fourth floor to allow for a possible self resetting of the appaldlus by running the elevator to either the highest or lowest floors in the case of a memory loss of the PLC. In some 2 speed installations the first floor down selector relay also sets and resets all the intermediate floor selector relays. It had been found that in the case of memory loss or initial set up of the system or during inspection runs this makes it easier to set up the system in applications with four or more floors.
The concept of the invention is that all the floor setting relays are interlocked with the relays above and below in such a way that the same signals from the up levelling switch 16 and down levelling switch 18 will only affect the next relay in the chain ready for setting or resetting.
Furthermore, the signals alternate to set and reset relays. For example, in the down direction, up levelling relay 170 plus down running relay 200, then down levelling relay 172 plus down running relay 200, then up levelling relay 170 plus down running relay 200 again. This effectively forces the control system to count the floors up and down without an input from any other source but the already existing levelling proximity switches is 16 and 18 in this embodiment with the existing vanes or, alternatively, the up slow down switch 12 and down slow down switch 14 in other embodiments.
The example discussed above is a single low speed elevator, with only four floors, however, this system can also be used on multi-speed, variable voltage and variable frequency installations and 5 for hydraulic as well as for cable, chain or any other drive system and for as many floors as the PLC has the capacity to provide sufficient relays. The system is adaptable for passenger and freight elevators, for dumbw~ , handicap lifts, residential lifts and possibly mining elevators and sky trams with multiple stops and for the speed control steps of elevator door operators. The system can also be operated in the set-reset mode as well as in the reset-set mode with the relays 10 either setting or resetting as the elevator leaves the floor, with self-holding circuits on single coil relays and possibly any other kind of stepper switch, electronic, possibly even built into some PLC's, or even mechanical latching relays could be substituted, as long as the signals from the levelling or the slow down switches and door zone contacts and from the running relays are arranged in the correct way.
It will be understood by someone skilled the art that many of the details provided above can be altered or deleted without departing from the scope of the invention which is to be in~el~r~led with reference to the following claims.
30 3. A relay-operated selector system is operated by intermittent floor switches mounted in proximity to the intermediate floors.
4. A relay-operated selector system is operated by intermediate floor switches mounted on the elevator car and actuated by vanes in different lanes at the intermediate floors.
s 5. A magnetic tape is employed to operate a microprocessor.
All of the above-described prior art systems require components of one type or another to be installed in the hoistway or in the machine room in order to register the location of the elevator 10 car in the hoistway, together with the required wiring, in addition to the hoistway limit switches, slowdown-, levelling- and door-zone contacts and switches, all of which are already employed on 2-landing elevators.
Slowdown- and levelling-contacts and switches are employed to slow the motion of the elevator 15 car as it reaches a selected floor, at which it stops, and also to keep the elevator car level with that selected floor until the elevator car moves away to a different floor.
It is, however, a disadvantage of the prior selector systems that, since they employ separate contacts or switches for regi~t~ring the movement of the elevator car past the building floors, on 20 one hand, and for levelling the elevator car relative to any floor at which the car is stopped, on the other hand, the costs of components, in~t~ tion and m~int~n:~nce are correspondingly high, and the reliability of the system, which is dependent on the number of components employed, is correspondingly degraded.
BRIEF SUMMARY OF THE INVENTION
It is, accordingly, an object of the present invention to provide a novel and improved elevator control system which employs a single set of switches for the dual purposes of registering the travel of the elevator car as it passes the floors of a multi-story building and for another purpose -such as levelling the elevator near any floors or slowing the elevator as it approaches a floor.
According to the invention there is provided an a~pald~us for controlling an elevator in a building having at least one intermediate floor between a top floor and a bottom floor thereof.
5 The apparatus includes first ~ign~lling means, for each said intermediate floor, for ~ign~lling a first signal when the elevator moves above said each intermediate floor. There is second si~;n~lling means, for said each intermediate floor, for sign~lling a second signal when the elevator moves below said each intermediate floor. Latching means for each said intermediate floor is operatively connected to the sign:~lling means for ch~ngin~ a latch state when the first 10 and second signals are received by the latch means. There is also means operatively connected to the latch means for controlling movement of the elevator depending upon the state of said each latch means.
The first ~i~n~lling means and the second ~i n~lling means may include vertically spaced-apart 15 first and second proximity switches on the elevator car and a stationary activating means at said each intermediate floor positioned for activating said each proximity switch as they move past said each activating means. For example, the proximity switches may be levelling switches or slow down switches for the elevator.
20 The latching means may include an up latch for each intermediate floor operatively connected to said each first ~i~n:~lling means and a down latch for each intermediate floor operatively connected to each said second ~ign~llin~ means. There is up direction indicating means for indicating when the elevator is moving up and down direction indicating means for indicating when the elevator is moving down. The up latch and the down direction ~ign~lling means are 25 operatively connected so each up latch is latched as the elevator moves down past said each intermediate floor. The down latch and the up direction indicating means are operatively connected so each down latch is latched as the elevator moves up past said each intermediate floor.
The l~tçhinE means may include up lml~t(~hing means for lml~tçhing each said up latch and down unlatching means for llnl~trhinE each said down latch. The up nnl~tçhing means is operatively connected to the up direction indicating means, whereby each said up latch is unlatched when the elevator moves up and approaches said each intermediate floor. The down unlatching means 5 is operatively connected to the down direction indicating means, whereby each said down latch is unlatched when the elevator moves down and approaches each said intermediate floor.
The up latch for each said floor and the means for unlatching thereof are preferably each connected to a contact opened by the unlatching means of a floor immediately below said each 10 floor. The down latch of each said floor and the means for unlatching thereof are preferably each connected to a contact opened by the unlatching means of a floor immediately above said each floor. Thus the ~i~n~llinE means latches or unlatches only one said l:~t~hing means with each said signal.
15 Another aspect of the invention provides a method for controlling movement of an elevator as required by a call system towards a selected floor. The elevator has a car with a pair of vertically spaced-apart, upper and lower proximity switches and means at each floor for actuating each said proximity switch. The method includes connecting each proximity switch to a digital processor.
The processor is programmed with software including up l~tçhinE means for each of a plurality 20 of floors, for latching when the upper proximity switch is actuated and the elevator is moving downwardly away from or past each said floor and for llnl~tchinE when the first proximity switch is actuated and the elevator is moving upwardly towards said each floor. The software also includes down latching means for said each floor for l~t~hinE when the second signal is produced and the elevator is moving upwardly away from or past said each floor and for unlatching when 25 the down proximity switch is actuated and the elevator is moving downwardly towards said each floor. The processor is connected to the call system so the latching means and unlatching means direct the elevator towards the floor required by the call system.
Thus, with the present elevator control system, a single set of proximity switches, mounted on the car, can be utilized both for the registration of the passage of the elevator car past the building floors, and also for levelling the elevator car at the building floors or a similar function such as slowing down of the elevator near floors.
5 Consequently, the number of components of the system is reduced, and the reliability of the operation of the system is correspondingly increased, as compared with the above-discussed prior art systems. Also, the initial installation costs, the m~t~ri:~l costs and the m~inten:~nce costs are correspondingly reduced as compared with the prior art systems. Furthermore the need for a levelling adju~tm~nt to compensate for the settling of the building as it ages may be avoided.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects, features and advantages of the present invention will be more readily apparent to those skilled in the art from the following description of an elevator control system according 15 to the present invention, when taken in conjunction with the accompanying drawings, in which:
Fig. 1 is a diagrammatic side elevation of an elevator and control system therefor according to an embodiment of the invention;
Fig. 2 is a block diagram of the control system thereof, Fig. 3a is a schematic ladder diagram of the contacts connected to the latching and unlatching relays of the control system;
Fig. 3b is a continll~tion of Fig. 3a; and Fig. 4 is a sçhem~tic diagram of the contacts, including contacts controlled by the l~tçhing relays, which are connected to the down direction and up direction relays for the elevator control system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, Fig. 1 illustrates a building shown generally at 15 which has four floors numbered 1, 2, 3, and 4 respectively. There is an elevator shown generally at 17 having 5 a car 19 capable of vertical movement between the floors. The elevator is equipped with five proximity switches in this example, proximity switch 12 being the up slow down switch which slows the car down when approaching a floor from below. Switch 16 is an up levelling switch which brings the elevator car up into position at the floor and will re-level it if it drops slightly below the floor when parked there, for example if a large load is added or due to hydraulic 10 sinking. Switch 20 is a door zone switch indicating that the elevator car is adjacent the door of a floor. Switch 18 is a down levelling switch which brings the elevator car down into position at the floor and re-levels it if the elevator moves slightly above the floor due to a change in the load. Switch 14 is a down slow down switch which slows the elevator car as it approaches a floor from above. Each of these switches is actuated by a vane for each floor, namely vanes 8, 9, 10 and 1 1 for floors 4, 3, 2 and 1 respectively. Each of the proximity switches provides a signal when the switch moves into position adjacent to one of the vanes. As described thus far, the arrangement is conventional for many elevators.
Conventional elevators include a different system for directing an elevator in the correct 20 direction towards a floor when a call button is pushed, either on the elevator or on the floor concerned. The present invention departs from such prior art elevators by lltili7ing the proximity switches described above in the floor selector system. All of the proximity switches are connected to a microprocessor 22 as shown schematically in Fig. 1. In this particular example the microprocessor is a Programmable Controller of a type commonly used in elevators. A
25 Series One or a Series One Plus Programmable Logic Controller (PLC) is used in this example.
In this preferred example of the invention all of the modifications to the equipment are carried out by way of software modifications to the PLC which can be carried out by someone skilled in the art with the aid of the disclosure herein. The invention can be best understood by explaining the functions of the components in terms of hardware such as relays, contacts and electrical connections as set forth below. However, these can be readily converted into appropliate software and such PLC's conventionally provide printouts of the programmed software in terms of combinations of relays and contacts. In fact, Fig.3 and 4 represent printouts from such a programmed PLC. The nurnbers shown in these figures refer to software functions 5 equivalent to relays as identified below:
PLC FUNCTIONS:
RELAY FUNCTION
160 First Floor Hall Call 161 2nd Floor Hall Call 162 3rd Floor Hall Call 163 Top Floor Hall Call 164 First Floor Car Call 165 2nd Floor Car Call 166 3rd Floor Car Call 167 Top Floor Call 170 Up Levelling Relay 171 DoorZoneRelay 172 Down Levelling Relay 173 Inspection Toggle SW
174 Run Relay Input 175 Insp. Up Toggle SW
176 Insp. Down Toggle SW
177 Key Switch 1. Main Control 200 Down Valve Output (or Down Pilot Relay) 201 Up Pilot Relay 202 Running Relay 203 Key Switch 2. Special Function _ 204 Down Direction Relay 205 Up Direction Relay 210 Upper Selector Protection Relay 211 Lower Selector Protection Relay 340 First Floor Down Selector Relay 341 2nd Floor Up Selector Relay 342 2nd Floor Down Selector Relay 343 3rd Floor Up Selector Relay 344 3rd Floor Down Selector Relay 345 Top Floor Up Selector Relay Referring to Fig. 3, this shows the contacts connected in series which must be closed in order to latch or unlatch (also referred to "set" or "reset") the floor selector relays 340,341, 342, 343,344 and 345. Each of these relays is a latching relay with two coils, one for l~t~ hing the latching the 15 relay and one for l-nl~tchin~ it. In Fig.3, the contact must be closed to latch a relay followed by "(SET)" and the contacts which must be closed to unlatch the relay are followed by "(RST)".
The contacts marked "]["are open when unenergized, while contacts "]/[" are closed when unenergized.
20 The top floor 4 and the bottom floor 1 are special cases as described below. The intermediate floors 3 and 2 operate in the same manner. Each has two relays, the up relays l~tching as the elevator car leaves the floor in the down direction and unlatching when the car approaches the floor in the up direction. There is also a down relay for each floor which latches when the elevator leaves the floor in the up direction and unlatches when the elevator car approaches the 25 floor from above. The a~aldlus and method are described further in relation to a specific case where the elevator car leaves, for example, the third floor in the down direction. In this particular example the up relays and down relays are latched and unlatched by signals from up levelling switch 16 and down levelling switch 18 respectively. In other examples these relays could be actuated by signals from the up slow down switch 12 and down slow down switch 14, such as on multi-or variable speed applications. In this example the up levelling switch 16 is connected to up levelling relay 170, while down levelling switch 18 is connected to down levelling relay 172. These relays close the contacts 170 and 172 respectively shown in Fig. 3 when the switches approach the vanes 8, 9, 10 and 11. Likewise the door zone switch 20 is S connected to a door zone relay 171 to close the contacts 171 when switch 20 is adjacent the vane.
In some 2 speed installations the door zone relay is omitted because the switching must be done some distance, 3.5 feet in one example, before the elevator reaches the floor to have a long enough slow down speed zone. There are two sets of contacts 200 and 201 in this case. The contacts 200 are connected to a down valve output which indicates that the elevator car is moving downwards, while relay 201 is an up running pilot which indicates that the elevator car is moving up. Thus contacts 200 are closed when the elevator car moves down and contacts 201 are closed when the elevator moves up. (In other applications relay 200 and its contacts may be used as a down pilot relay in the same manner as relay 201 is used as an up pilot relay.) The contacts 340, 341, 342, 343, 344 and 345 are closed by the correspondingly numbered latching relays. In this example a 2 second timer Tl is connected in series with relay 200 as shown in Fig. 3b and a similar timer T2 in series with relay 201. These extend the up or down running signal for a slightly longer time than it takes the elevator to come to a sliding stop when operated on inspection. This could allow an up or down slow down switch to slide through a vane without the presence of the running signal, thus giving an incorrect floor count. The timed relays are de~i~n~ted 200T and 201T in Fig. 3a and the top of Fig. 3b.
Supposing the elevator car, for example, leaves the third floor in the down direction, this causes up levelling switch 16 to pass by vane 9 as the elevator leaves the floor. Thus a signal is provided to up levelling relay 170 which closes the corresponding contact 170 on the coil ofthird floor up selector relay 343. The down running relay 200 is closed since the elevator car is moving down and relay 171 is closed because the elevator car is still at the door zone. Contact 342 is closed because the second floor down selector 342 is still latched because the elevator car is above the floor and would move down to the second floor if called thereto. Contact 344 is a normally closed contact which is closed, indicating that third floor down selector relay 344 was -reset as proximity switch 18 passed by vane 9 as the elevator approaches the third floor the last time from above. Thus third floor up selector relay 343 is latched and will route all calls to this floor to the up direction relay 205 as shown in Fig. 4. Thus either the third floor hall call 162 or the third floor car call 166 are routed to up direction relay 205 via contacts of the third floor selector relay 343, down direction relay 204 and the rem~ining closed contacts which are not pertinent to this discussion.
A second contact from relay 343 in the reset coil circuit of second floor down selector relay 342 is closed when the relay 343 is latched. When the proximity switch 18 approaches vane 10 down 10 levelling relay 172 is closed along with its corresponding contact on the reset coil of relay 342.
Also the down running relay 200 is closed together with the normally closed contact 341 of the second floor up selector relay and the contact of the third floor up selector relay described above.
Thus second floor down selector relay 342 is unlatched in the moment when the door zone relay 171 is pulled in by its corresponding ploxi~ y switch 20 when it approaches vane 10 and closes 15 its contact 171 in the re-set circuit of relay 342. This means that second floor hall call 161 and second floor car call 165 no longer route calls to the down direction relay 204 as shown in Fig.
4. The second floor up selector 341 is not set until the elevator moves below the second floor.
Two normally closed contacts from the unlatched relays 341 and 342 indicate that the elevator is within the second floor zone and, if a call to the floor is registered, the elevator car will go into 20 low speed if so equipped, or when reaching the second floor vane 10 with the door zone switch 20, activates the door zone relay 171. The elevator car goes into ~lltom~tic levelling and will then stop at the level of the second floor.
As relay 342 is lml~t~lled, a 342 contact in the reset coil of the third floor up selector relay 343 25 is opened, thus disabling relay 343 from resetting when the up levelling relay 170 is activated as proximity switch 18 moves by vane 10 as the elevator car moves down to the first floor. In this manner, only one of the floor selector relays is set to be latched each time the proximity switch moves by one of the vanes.
If the elevator car continues to move down to the first floor, then second floor up selector relay 341 is latched in the same way as relay 343 wæ latched when the elevator car left the third floor in the down direction as described above. This locks out the reset circuit of the second floor down selector relay 342 and routes all calls to the second floor to the up direction relay 205 shown in Fig. 4. If the elevator car instead moves up, the second floor down selector relay 342 is set by the down levelling relay 172 connected to proximity switch 18 as it passes the second floor vane 10. A call to the second floor is now routed to the down direction relay 204 and the 342 contact in the 343 reset circuit closes so the relay 343 is unlatched when the up levelling switch and relay 170 are activated by the vane on the third floor.
The description of the above is typical for any intermediate floor on a multi floor building.
However the top floor and bottom floor are special cases. The first floor down selector relay 340 and the fourth up selector relay 345 are reverse operating, setting as the elevator reaches the first or fourth floor to allow for a possible self resetting of the appaldlus by running the elevator to either the highest or lowest floors in the case of a memory loss of the PLC. In some 2 speed installations the first floor down selector relay also sets and resets all the intermediate floor selector relays. It had been found that in the case of memory loss or initial set up of the system or during inspection runs this makes it easier to set up the system in applications with four or more floors.
The concept of the invention is that all the floor setting relays are interlocked with the relays above and below in such a way that the same signals from the up levelling switch 16 and down levelling switch 18 will only affect the next relay in the chain ready for setting or resetting.
Furthermore, the signals alternate to set and reset relays. For example, in the down direction, up levelling relay 170 plus down running relay 200, then down levelling relay 172 plus down running relay 200, then up levelling relay 170 plus down running relay 200 again. This effectively forces the control system to count the floors up and down without an input from any other source but the already existing levelling proximity switches is 16 and 18 in this embodiment with the existing vanes or, alternatively, the up slow down switch 12 and down slow down switch 14 in other embodiments.
The example discussed above is a single low speed elevator, with only four floors, however, this system can also be used on multi-speed, variable voltage and variable frequency installations and 5 for hydraulic as well as for cable, chain or any other drive system and for as many floors as the PLC has the capacity to provide sufficient relays. The system is adaptable for passenger and freight elevators, for dumbw~ , handicap lifts, residential lifts and possibly mining elevators and sky trams with multiple stops and for the speed control steps of elevator door operators. The system can also be operated in the set-reset mode as well as in the reset-set mode with the relays 10 either setting or resetting as the elevator leaves the floor, with self-holding circuits on single coil relays and possibly any other kind of stepper switch, electronic, possibly even built into some PLC's, or even mechanical latching relays could be substituted, as long as the signals from the levelling or the slow down switches and door zone contacts and from the running relays are arranged in the correct way.
It will be understood by someone skilled the art that many of the details provided above can be altered or deleted without departing from the scope of the invention which is to be in~el~r~led with reference to the following claims.
Claims (18)
1. An apparatus for controlling an elevator in a building having at least one intermediate floor between a top floor and a bottom floor thereof, the apparatus comprising:
first signalling means, for each said intermediate floor, for signalling a first signal when the elevator moves above said each intermediate floor;
second signalling means for said each intermediate floor for signalling a second signal when the elevator moves below said each intermediate floor;
latching means, for each said intermediate floor and operatively connected to the signalling means, for changing a latch state when the first and second signals are received by the latching means; and means operatively connected to the latching means for controlling movement of the elevator depending upon the state of said each latching means.
first signalling means, for each said intermediate floor, for signalling a first signal when the elevator moves above said each intermediate floor;
second signalling means for said each intermediate floor for signalling a second signal when the elevator moves below said each intermediate floor;
latching means, for each said intermediate floor and operatively connected to the signalling means, for changing a latch state when the first and second signals are received by the latching means; and means operatively connected to the latching means for controlling movement of the elevator depending upon the state of said each latching means.
2. An apparatus as claimed in claim 1, wherein the first and second signalling means respectively comprise vertically spaced-apart first and second proximity switches on the elevator and a stationary activating means at each said floor for activating said each proximity switch as said each proximity switch moves past the activating means.
3. An apparatus as claimed in claim 2, wherein the proximity switches are levelling switches for the elevator.
4. An apparatus as claimed in claim 2, wherein the proximity switches are slow down switches for the elevator.
5. An apparatus as claimed in claim 1, wherein the latching means includes an up latch for said each intermediate floor operatively connected to each said first signalling means, a down latch for said each intermediate floor operatively connected to each said second signalling means, up direction indicating means for indicating when the elevator is moving up and down direction indicating means for indicating when the elevator is moving down, the up latch and the down direction indicating means being operatively interconnected so each said up latch is latched as the elevator moves down and the down latch and the up direction indicating means being operatively interconnected so each said down latch is latched as the elevator moves up.
6. An apparatus as claimed in claim 5, wherein the latching means includes up unlatching means for unlatching each said up latch and down unlatching means for unlatching each said down latch, the up unlatching means being operatively interconnected with the up direction indicating means, whereby each said up latch is unlatched as the elevator moves up and approaches said each intermediate floor and the down unlatching means being operatively interconnected with the down direction indicating means, whereby each said down latch is unlatched as the elevator moves down and approaches said each intermediate floor.
7. An apparatus as claimed in claim 6, wherein the up latch for each said floor and the means for unlatching thereof are each connected to a contact opened by said unlatching means of a floor immediately below said each floor and said down latch for each said floor and the means for unlatching thereof are each connected to a contact opened by said unlatching means of a floor immediately above said each floor, whereby said signalling means latch or unlatch only one said latching means with each said signal.
8. An apparatus as claimed in claim 1, wherein the apparatus includes control means for directing the elevator to a selected said floor, said control means being connected to the means for controlling movement of the elevator, whereby the state of said latching means directs the elevator towards said selected floor.
9. An elevator control apparatus for an elevator having a car for a building having at least one intermediate floor between top and bottom floors thereof, the apparatus comprising:
an upper proximity switch and a lower proximity switch mounted on the car and vertically spaced-apart from each other;
means at each said intermediate floor for activating the upper proximity switch and the lower proximity switch to produce first and second signals respectively as the proximity switches move adjacent said means;
up latching means for each said intermediate floor for latching when the first signal is produced and the elevator moves downwardly past said each intermediate floor and for unlatching when the first signal is produced and the elevator is moving upwardly towards said each intermediate floor;
down latching means for each said intermediate floor for latching when the second signal is produced and the elevator moves upwardly past said each intermediate floor and for unlatching when the second signal is produced and the elevator is moving downwardly toward said each intermediate floor; and controlling means connected to said latching means for controlling elevator movement according to which said latching means are latched and unlatched.
an upper proximity switch and a lower proximity switch mounted on the car and vertically spaced-apart from each other;
means at each said intermediate floor for activating the upper proximity switch and the lower proximity switch to produce first and second signals respectively as the proximity switches move adjacent said means;
up latching means for each said intermediate floor for latching when the first signal is produced and the elevator moves downwardly past said each intermediate floor and for unlatching when the first signal is produced and the elevator is moving upwardly towards said each intermediate floor;
down latching means for each said intermediate floor for latching when the second signal is produced and the elevator moves upwardly past said each intermediate floor and for unlatching when the second signal is produced and the elevator is moving downwardly toward said each intermediate floor; and controlling means connected to said latching means for controlling elevator movement according to which said latching means are latched and unlatched.
10. An apparatus as claimed in claim 9, having one said up latching means and one said down latching means for each of a plurality of floors, the latching means being operatively interconnected so only one said latching means is latched or unlatched as each said signal is produced.
11. An apparatus as claimed in claim 10, wherein the latching means are operatively interconnected by means of a contact in series with each said latching means which is closed by another said latching means.
12. An apparatus as claimed in claim 10, wherein the proximity switches are connected to a car levelling system for levelling the car at each said floor.
13. An apparatus as claimed in claim 12, wherein the proximity switches are connected to a car slow down system for each said floor.
14. An apparatus as claimed in claim 9, including a floor selector system including selector means for selecting a particular floor to which the elevator is to move, the selector means, the controlling means and the latching means being operatively inter-connected to move the elevator in an appropriate direction towards said particular floor.
15. An apparatus as claimed in claim 9, wherein the top floor has an up latching means and the bottom floor has a down latching means.
16. An apparatus as claimed in claim 9, wherein the latching means and the controlling means comprise a digital processor and associated software.
17. An elevator control apparatus, comprising a car levelling system and a floor selector system, the floor selector system including means for monitoring information from the car levelling system and for determining the position of the elevator from said information.
18. A method for controlling movement of an elevator as required by a call system towards a selected floor, said elevator having a car with a pair of vertically spaced-apart, upper and lower proximity switches and means at each floor for actuating each said proximity switch, the method comprising:
connecting each said proximity switch to a digital processor;
programming said processor with software including up latching means for changing a state when the upper proximity switch is actuated at said each floor and the elevator is moving downwardly and when the upper proximity switch is actuated at said each floor and the elevator is moving upwardly, down latching means for changing a state when the lower proximity switch is actuated at each floor and the elevator is moving upwardly and when the lower proximity switch is actuated at said each floor and the elevator is moving downwardly; and connecting said processor to the call system so the latching means and to direct the elevator toward the floor required according to the call system.
connecting each said proximity switch to a digital processor;
programming said processor with software including up latching means for changing a state when the upper proximity switch is actuated at said each floor and the elevator is moving downwardly and when the upper proximity switch is actuated at said each floor and the elevator is moving upwardly, down latching means for changing a state when the lower proximity switch is actuated at each floor and the elevator is moving upwardly and when the lower proximity switch is actuated at said each floor and the elevator is moving downwardly; and connecting said processor to the call system so the latching means and to direct the elevator toward the floor required according to the call system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25592594A | 1994-06-07 | 1994-06-07 | |
| US08/255,925 | 1994-06-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2150964A1 true CA2150964A1 (en) | 1995-12-08 |
Family
ID=22970419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2150964 Abandoned CA2150964A1 (en) | 1994-06-07 | 1995-06-05 | Elevator control systems |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2150964A1 (en) |
-
1995
- 1995-06-05 CA CA 2150964 patent/CA2150964A1/en not_active Abandoned
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