ELEVATOR SYSTEMS WITH IMPROVED MONITORING

Abstract

An elevator system (201) includes an elevator car (203) arranged to move within an elevator shaft, an elevator drive (211) including a brake (208), an elevator controller (230) configured to control the elevator drive so as to control the movement of the elevator car between a plurality of landings in the elevator shaft, a position reference system (240) configured to measure a position of the elevator car within the elevator shaft, and a safety controller (232) connected to the position reference system (240) to receive car position information and configured to selectively apply the brake of the elevator drive so as to stop the elevator car. The safety controller is configured to monitor the received car position information at least when the elevator car is moving in a designated unlocking zone of a given landing with an elevator car door open and to apply the brake.

Claims

1. An elevator system (201) comprising: an elevator car (203) arranged to move within an elevator shaft (117); an elevator drive (211) including a brake (208); an elevator controller (230) configured to control the elevator drive (211) so as to control the movement of the elevator car (203) between a plurality of landings (125) in the elevator shaft (117); a position reference system (240) configured to measure a position of the elevator car (203) within the elevator shaft (117); a safety controller (232) connected to the position reference system (240) to receive car position information and configured to selectively apply the brake (208) of the elevator drive (211) so as to stop the elevator car (203), wherein the safety controller (232) is configured to monitor the received car position information at least when the elevator car (203) is moving in a designated unlocking zone (260) of a given landing (125) with an elevator car door open and to apply the brake (208) of the elevator drive (211) upon determining from the received car position information that the position of the elevator car (203) is outside a designated movement zone (250) of the given landing (125), and wherein the safety controller (232) is further configured to monitor the received car position information after the brake (208) has been applied to stop the elevator car (203) with an elevator car door open and to compare the position of the stopped elevator car to the designated unlocking zone (260) of the given landing (125).

2. The elevator system of claim 1, wherein the safety controller (232) is further configured to make one or more decisions relating to a safety status after the elevator car (203) has left the designated movement zone (250).

3. The elevator system of claim 1, wherein, when the safety controller (232) determines that the position of the stopped elevator car is within the designated unlocking zone (260) of the given landing, the brake (208) is allowed to be released by the safety controller (232).

4. The elevator system of claim 1, wherein, when the safety controller (232) determines that the position of the stopped elevator car is outside the designated unlocking zone (260) of the given landing, the brake (208) can only be released by an external intervention to reset the safety controller (232).

5. The elevator system of claim 1, wherein the designated movement zone (250) of the given landing (125) is smaller than the designated unlocking zone (260) of the given landing.

6. The elevator system of claim 1, wherein the safety controller (232) is configured to monitor the received car position information during an elevator car re-levelling operation.

7. The elevator system of claim 1, wherein the position reference system (240) is configured to measure a relative position of the elevator car (203) from the given landing.

8. The elevator system of claim 1, wherein the position reference system (240) is configured to continuously measure an absolute position of the elevator car within the elevator shaft.

9. The elevator system of claim 1, wherein the safety controller (232) is connected to a plurality of safety devices (234) in a safety chain.

10. A method of monitoring an elevator car (203) moving with an elevator car door open in an elevator system (201) comprising an elevator car arranged to move between a plurality of landings (125) in an elevator shaft (117), the method comprising: measuring a position of the elevator car (203) within the elevator shaft; monitoring the position of the elevator car (203) at least when the elevator car is moving in a designated unlocking zone (260) of a given landing (125) with an elevator car door open and applying a brake (208) to the elevator car (203) upon determining that the position of the elevator car moving with an elevator car door open is outside a designated movement zone (250) of the given landing; and further monitoring the position of the elevator car (203) after the brake (208) has been applied to stop the elevator car with an elevator car door open and comparing the position of the stopped elevator car to the designated unlocking zone (260) of the given landing.

11. The method of claim 10, further comprising: making one or more decisions relating to a safety status after the elevator car (203) has left the designated movement zone (250).

12. The elevator system of claim 10, further comprising: allowing the brake (208) to be released upon determining that the position of the stopped elevator car is within the designated unlocking zone (260) of the given landing.

13. The elevator system of claim 10, further comprising: preventing the brake (208) from being released, without an external intervention, upon determining that the position of the stopped elevator car is outside the designated unlocking zone (260) of the given landing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Certain examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

[0035] FIG. 1 is a schematic illustration of a typical elevator system that may employ examples of the present disclosure;

[0036] FIG. 2 is a schematic illustration of an elevator system according to an example of the present disclosure;

[0037] FIG. 3 is a schematic illustration of an elevator car position relative to a given landing for an elevator car moving with an elevator car door open in an example wherein: (a) the brake can be released; and (b) a blockage is required;

[0038] FIG. 4 is a flow chart illustrating a method of monitoring an elevator car moving with an elevator car door open according to an example of the present disclosure.

DETAILED DESCRIPTION

[0039] FIG. 1 is a perspective view of an elevator system 101 including an elevator car 103, a counterweight 105, a tension member 107, a guide rail 109, an elevator drive 111, an encoder 113, and a controller 115. The elevator car 103 and counterweight 105 are connected to each other by the tension member 107. The tension member 107 may include or be configured as, for example, ropes, steel cables, and/or coated-steel belts. The counterweight 105 is configured to balance a load of the elevator car 103 and is configured to facilitate movement of the elevator car 103 concurrently and in an opposite direction with respect to the counterweight 105 within an elevator shaft 117 and along the guide rail 109.

[0040] The tension member 107 engages the elevator drive 111, which is part of an overhead structure of the elevator system 101. The elevator drive 111 is configured to control movement between the elevator car 103 and the counterweight 105, and thus control the position of the elevator car 103 within the elevator shaft 117. The encoder 113 may be mounted on a fixed part at the top of the elevator shaft 117, such as on a support or guide rail, and may be configured to provide position signals related to a relative position of the elevator car 103 within the elevator shaft 117. The encoder 113 is typically connected to the controller 115 so that the controller 115 can monitor the speed and motion profile of the elevator car 103 as it is driven to move between one or more landings 125 in the elevator shaft 117.

[0041] The controller 115 is shown as located in a controller room 121 of the elevator shaft 117 and is configured to control the operation of the elevator car 103. For example, the controller 115 may provide drive signals to the elevator drive 111 to control the acceleration, deceleration, levelling, stopping, re-levelling, etc. of the elevator car 103. The controller 115 may also be configured to receive position signals from the encoder 113 or any other desired position reference system. When moving up or down within the elevator shaft 117 along the guide rail 109, the elevator car 103 may stop at the one or more landings 125 as controlled by the controller 115. Although shown in a controller room 121, those of skill in the art will appreciate that the controller 115 can be located and/or configured in other locations or positions within the elevator system 101. For example, the controller may be located remotely or in the cloud.

[0042] The elevator drive 111 may include a motor or similar driving mechanism, and a brake. The elevator drive 111 may be configured to include an electrically driven motor and an electrically released brake. The power supply for the motor and/or brake may be any power source, including a power grid, which, in combination with other components, is supplied to the elevator drive 111. The elevator drive 111 may include a traction sheave, moved by the motor, that imparts force to tension member 107 to move the elevator car 103 within elevator shaft 117.

[0043] Although shown and described with a roping system including a tension member 107, elevator systems that employ other methods and mechanisms of moving an elevator car within an elevator shaft may employ examples of the present disclosure, with the tension member 107 being omitted. For example, ropeless elevator systems may use a linear motor or a hydraulic device to directly drive movement of the elevator car 103. FIG. 1 is merely a non-limiting example presented for illustrative and explanatory purposes. Features of the elevator system 101 may be applied to the elevator system described in more detail below.

[0044] FIG. 2 is a schematic illustration of an elevator system 201 in accordance with an example of the present disclosure. As shown, the elevator system 201 comprises an elevator car 203 which is movable in an elevator shaft between a plurality of landings. The elevator car 203 is suspended by a tension member 207 which is driven by an elevator drive 211. The elevator drive 211 is thus configured to move the elevator car 203, via the tension member 207, in the elevator shaft.

[0045] The elevator drive 211 includes a motor 206 and a brake 208, e.g. in the form of a machine brake arranged to act directly on the motor 206 (or its associated traction sheave) such that when the brake 208 is applied movement of the motor 206 is stopped, and consequently the elevator car 203 is stopped from moving within the elevator shaft.

[0046] The elevator system 201 comprises an elevator controller 230 and a safety controller 232. The elevator controller 230 is operatively connected to the elevator drive 211 to control movement of the elevator car 203 within the elevator shaft. The safety controller 232 is operatively connected to the elevator drive 211, independently of the elevator controller 230, so as to control the brake 208. There is also shown an exemplary safety device 234 operatively coupled to the safety controller 232. The safety device 234 may monitor a part of the elevator system, for example a sensor to detect the opening of the door(s) of the elevator car 203. Whilst the safety device 234 is illustrated as a single safety device 234, it may comprise a plurality of safety devices in a safety chain, for example limit switches, landing door sensors, load sensors, speed sensors, emergency stop buttons, etc.

[0047] The elevator system 201 further comprises a dedicated position reference system 240. The position reference system 240 may be mounted to the elevator car 203, as shown, or mounted elsewhere in the elevator shaft. The position reference system 240 may be any suitable system that is capable of determining a relative or absolute position of the elevator car 203 within the elevator shaft. The position reference system 240 is in direct communication with the safety controller 232 in this example. Although not shown, the position reference system 240 may optionally be in communication with the elevator controller 230 as well.

[0048] Operation of the elevator system 201 will now be described with reference to FIGS. 2 and 3, and the flow diagram of FIG. 4.

[0049] When the elevator car 203 is moving in the vicinity of a landing 125 with an elevator car door open, e.g. during a re-levelling operation of the elevator car 203 to bring the floor of the elevator car 203 into alignment with the floor of a given landing, the safety controller 232 is configured to monitor the car position information received from the position reference system 240. FIG. 3 shows the motion profile of an elevator car 203 as an overlaid plot of speed (s) versus time (t) when the elevator car 203 is moving in the vicinity of a landing 125 with an elevator car door open. As understood with reference to FIG. 3, the safety controller 232 monitors the received car position information to evaluate whether the elevator car 203 leaves the designated movement (e.g. re-levelling) zone 250 and the brake 208 needs to be applied. After the brake 208 has been applied in an “estop”, the safety controller 232 continues to monitor the received car position information to evaluate whether the elevator car 203 remains within the designated unlocking zone 260. The safety controller 232 compares the position of the stopped elevator car (denoted by a square) to the designated unlocking zone 260.

[0050] Based on this evaluation, the safety controller 232 can make a decision about whether the stopped elevator car has an unsafe status requiring a blockage (e.g. outside the designated unlocking zone 260 with an elevator car door open), as seen in FIG. 3(b), or a safe status (e.g. inside the designated unlocking zone 260 with an elevator car door open), as seen in FIG. 3(a). When a safe status is determined, the safety controller 232 can allow the brake 208 to be released for the elevator controller 230 to move the elevator car 203 again, e.g. to attempt another re-levelling operation (as shown by the dotted line). In the example seen in FIG. 3(a), this allows the re-levelling operation to recover without requiring a callout for external intervention.

[0051] This further monitoring of the position of the stopped elevator car and comparison to the designated unlocking zone 260 can prevent unnecessary (i.e. “nuisance”) blockages from occurring. This approach is also helpful for elevator systems having an increased blockage sensitivity, e.g. due to a relatively small designated movement zone 250, such as only ±40 mm from the landing 125. For example, if a glitch in the safety chain causes the safety controller 232 to apply the brake 208 (i.e. an “estop” when the elevator car 203 is just 2 mm inside the designated movement zone 250 and the subsequent relevel run has a 3 mm roll-back, then a blockage would be triggered without the further monitoring seen in FIG. 3a. The monitoring system and method described herein therefore allows movement of the elevator car to be recovered without an external intervention.

[0052] Some steps of this exemplary method are illustrated in FIG. 4. At step 350, the safety controller 232 uses car position information received from the position reference system 240 to monitor the position of the elevator car 203 throughout a car re-levelling operation. At step 352, the safety controller 232 evaluates whether the position of the elevator car 203 is outside the designated re-levelling zone 250. The car re-levelling operation can continue as long as the elevator car 203 remains within the designated re-levelling zone 250, as shown at step 354. When the elevator car 203 is outside the designated re-levelling zone 250, the safety controller 232 applies the brake 208 to stop the elevator car 203 at step 356.

[0053] Unlike conventional systems, the safety controller 232 continues to monitor the position of the elevator car 203 even after the brake 208 has been applied and the elevator car is coming to a standstill. At step 358, the safety controller 232 evaluates whether the position of the stopped elevator car falls outside the designated unlocking zone 260. If the stopped position of the elevator car 203 is outside the designated unlocking zone 260 then the safety controller 232 registers a blockage, as shown at step 360. This corresponds to FIG. 3(b). However, if the stopped position of the elevator car 203 is within the designated unlocking zone 260 then the safety controller 232 can allow the brake 208 to be released, as shown at step 362. This corresponds to FIG. 3(a), wherein a nuisance blockage is avoided.