Elevator systems

Abstract

An elevator system 2 is provided which comprises: a hoistway 6 accessible by at least one hoistway door 10a, 10b, 10c; at least one elevator car 4 located in the hoistway 6; a hoistway door switch 12a, 12b, 12c associated with the at least one hoistway door 10a, 10b, 10c; at least one inspection switch 16; at least one emergency stop switch 18; and an elevator controller 24. The elevator controller 24 is configured to monitor the hoistway door switch 12a, 12b, 12c, the inspection switch 16 and the emergency stop switch 18 and to prevent inspection mode operation of the elevator car 4 until at least one change of state is detected of each of the hoistway door switch 12a, 12b, 12c, the inspection switch 16 and the emergency stop switch 18.

Claims

1. An elevator system comprising: a hoistway accessible by at least one hoistway door; at least one elevator car located in the hoistway; a hoistway door switch associated with the at least one hoistway door; at least one inspection switch; at least one emergency stop switch; and an elevator controller; wherein the elevator controller is configured: to monitor the hoistway door switch, the inspection switch and the emergency stop switch; and to prevent inspection mode operation of the elevator car until at least one change of state is detected of each of the hoistway door switch, the inspection switch and the emergency stop switch.

2. The elevator system as claimed in claim 1, wherein the inspection switch is located within the hoistway.

3. The elevator system as claimed in claim 2, wherein the inspection switch is located on top of the elevator car or in a hoistway pit area.

4. The elevator system as claimed in claim 1, further comprising a set of elevator inspection controls.

5. The elevator system as claimed in claim 1, wherein the emergency stop switch is located within the hoistway.

6. The elevator system as claimed in claim 5, wherein the emergency stop switch is located on top of the elevator car or in a hoistway pit area.

7. The elevator system as claimed in claim 1, further comprising one or more additional switches and wherein the elevator controller is further configured to prevent inspection mode operation of the elevator car until at least one change of state is detected of each of the one or more additional switches.

8. The elevator system as claimed in claim 1, wherein the elevator controller is arranged to indicate the switches of which at least one change of state has been detected.

9. The elevator system as claimed in claim 1, wherein the elevator controller is configured to prevent all operation of the elevator system if a change of state is detected of at least one, but not all of the switches.

10. A method of operating an elevator system comprising at least one elevator car located in a hoistway, said hoistway being accessible by at least one hoistway door, the method comprising: monitoring a hoistway door switch associated with the at least one hoistway door, an inspection switch and an emergency stop switch; and preventing inspection mode operation of the elevator car until at least one change of state is detected of each of the hoistway door switch, the inspection switch and the emergency stop switch.

11. The method as claimed in claim 10, further comprising subsequently returning the elevator system to a normal mode if, whilst the elevator system is operating in the inspection mode, the inspection switch is placed into a normal operation position.

12. The method as claimed in claim 11 wherein, once normal operation has been resumed from the inspection mode, further comprising preventing subsequent operation of the elevator system in the inspection mode until another change of state is detected of each of the hoistway door switch, the inspection switch and the emergency stop switch.

Description

DRAWING DESCRIPTION

(1) Certain examples of the present disclosure will now be described with reference to the accompanying drawings in which:

(2) FIG. 1 shows an elevator system according to an example of the present disclosure;

(3) FIG. 2 is a flow chart illustrating a conventional (prior art) method of activating an inspection mode of an elevator system; and

(4) FIG. 3 is a flow chart illustrating a method of operating an elevator system according to an example of the present disclosure.

DETAILED DESCRIPTION

(5) FIG. 1 shows an elevator system 2 for transporting passengers within a building. The elevator system 2 comprises an elevator car 4 that is arranged to move within a hoistway 6 to carry passengers between floors 8a, 8b, 8c of the building. Each floor 8a, 8b, 8c has a hoistway door 10a, 10b, 10c used by passengers to access the elevator car 4.

(6) In normal operation, the elevator car 4 moves in the hoistway 6 to transport passengers between the floors 8a, 8b, 8c, for example in response to hall calls or destination calls entered by the passengers. In normal operation, the hoistway doors 10a, 10b, 10c open only to allow access to the elevator car 4 and are arranged not to open unless the elevator car 4 is aligned therewith.

(7) However, access to the inside of the hoistway 6 may occasionally be required by a technician or engineer, e.g. to carry out inspection of or maintenance to the elevator system 2. On such occasions, the hoistway doors 10a, 10b, 10c may be used to access directly the hoistway 6. The technician may use an override switch (not shown) or simply manual force to open one of the hoistway doors 10a, 10b, 10c whilst the elevator car 4 is not aligned therewith, thus granting the technician access to the hoistway 6. In FIG. 1 the elevator car is shown adjacent to the first floor 8b of the building.

(8) Before a technician enters the hoistway 6, however, normal operation of the elevator system 2 must be prevented, to avoid unexpected motion of the elevator car 4 (e.g. in response to a passenger call on another floor) whilst the technician is within the hoistway 6.

(9) Each of the hoistway doors 10a, 10b, 10c, is therefore provided with a hoistway door switch 12a, 12b, 12c. The hoistway door switches 12a, 12b, 12c are arranged to change state when a hoistway door 10a, 10b, 10c is opened. The elevator system 2 is configured such that when one or more of the hoistway door switches 12a, 12b, 12c indicates that one or more hoistway doors 10a, 10b, 10c is open onto the hoistway 6, normal operation is prevented. This mitigates the likelihood of unexpected movement of the elevator car 4 whilst a technician is inspecting the hoistway 6.

(10) During an elevator inspection, a technician may perform an “inspection run”, in which the elevator car 4 is moved (normally at a slow speed) in the hoistway 6 under manual control of the technician. During an inspection run, movement of the elevator car 4 is controlled using inspection controls 14 located on top of the elevator car 4 (e.g. comprising up and down buttons). The elevator system 2 must be in an inspection mode for the inspection controls 14 to be used (i.e. they are not functional unless the system 2 is in the inspection mode). The elevator system 2 is put in the inspection mode by switching an inspection switch 16 to an INSPECTION position. The inspection switch 16 is located with the inspection controls 14 on top of the elevator car 4. Placing the elevator system 2 in the inspection mode prevents normal operation of the elevator system 2. Normal operation of the elevator system 2 may be resumed by switching the inspection switch 16 to a NORMAL position (subject to normal operation not being otherwise prevented).

(11) During an inspection run, the technician therefore operates the controls 14 from the top of the elevator car 4 within the hoistway 6. In order to mitigate the risks associated with moving the elevator car 4 whilst a technician is within the hoistway 6, an emergency stop switch 18 is also provided on top of the elevator car 4, which can be operated by the technician to stop all motion of the elevator car 4 in case of an emergency to prevent injury. A secondary emergency stop switch 20 is also provided in a pit 22 of the hoistway 6.

(12) The hoistway door switches 12a, 12b, 12c, the inspection controls 14, the inspection switch 16 and the emergency stop switch 18 are all connected to an elevator controller 24. The elevator controller 24 controls operation of the elevator car 4 (e.g. by receiving elevator calls and dispatching elevators to serve them).

(13) Before performing any inspection from within the hoistway 6, a technician must be confident that the hoistway door switches 12a, 12b, 12c, the inspection switch 16 and the emergency stop switch 18 are not faulty.

(14) A conventional method for operating the elevator system 2 which aims to ensure safe inspection hoistway access is shown in FIG. 2. The process of FIG. 2 will be discussed here in relation to a particular example with reference to FIG. 1, in which a technician is located on the second floor 8c of the building. In step 202, the hoistway door 10c of the second floor 8c is opened (e.g. using an override switch or through manual means) to grant access to the hoistway 6. The correct operation of the hoistway door switch 12c is then checked at step 204 by testing if the elevator system 2 operates normally (e.g. by placing an elevator call on a hall call input panel). If the elevator car 4 begins to move even whilst the hoistway door 10c is open, the technician knows that the hoistway door switch 12c (which should prevent normal operation whilst the hoistway door 10c is open) is faulty and can investigate accordingly in step 206. However, if normal operation is successfully prevented, the technician can be confident in the operation of the hoistway door switch 12c and can proceed to step 208.

(15) In step 208, the technician reaches into or enters the hoistway 6 (e.g. by stepping onto the top of the elevator car 4, which is aligned with the first floor 8b). The emergency stop switch 18 is placed into the STOP position (which should prevent all movement of the elevator car 4 no matter the setting of other switches). Then, in step 210, the technician fully exits the hoistway 6 and closes the hoistway door 10c (so that the emergency stop switch 18 is the only mechanism preventing movement of the elevator car 4 and is thus tested individually).

(16) In step 212, the operation of the elevator system 2 is again checked (as in step 204). If the elevator car 4 begins to move, the technician knows that the emergency stop switch 18 is faulty and can investigate accordingly in step 214. If, however, movement of the elevator car 4 is correctly prevented, the technician proceeds to step 216, in which the hoistway door 10c is opened, the emergency stop switch 18 placed in the GO position and the inspection switch 16 placed in the INSPECTION position (which should enable inspection mode and prevent normal operation of the elevator system 2).

(17) The technician then, in step 218, again fully exits the hoistway 6 and closes the hoistway door 10c (as in step 210). Normal operation of the elevator system 2 is then checked in step 220. If the elevator car 4 begins to move, the technician knows that the inspection switch 16 is faulty and can investigate accordingly in step 222. However, if movement of the elevator car 4 is correctly prevented, the technician can proceed to step 224, in which he enters the hoistway 6 and uses the inspection controls 14 to perform an inspection run.

(18) By following all these steps, the technician can be sure that each of the switches is operating correctly before he enters the hoistway 6 and performs the inspection run (i.e. before he is placed in any risk of injury if the elevator car 4 moves unexpectedly). However, this procedure is long and relies upon the diligence of the technician to correctly perform each of the steps. If the technician, for instance, neglects (e.g. through lack of training or forgetfulness) to test the emergency stop switch 18 before entering the elevator hoistway 6, the inspection run can still be performed (despite the functionality of the emergency stop switch 18 being not guaranteed). This can lead to unsafe inspection operation and may even lead to serious injury if a switch is indeed faulty and normal operation of the elevator system 2 is not prevented when it should be.

(19) However, FIG. 3 shows a method according to an example of the present disclosure which resolves many of these issues.

(20) As for the method described with reference to FIG. 2, a technician is assumed to be located on the second floor 8c of the building and wishes to access the top of the elevator car 4 to perform an inspection run.

(21) In step 302, the technician opens the hoistway door 10c of the second floor 8c. The correct operation of the hoistway door switch 12c is then checked in step 304 by testing if the elevator system 2 operates normally (e.g. by placing an elevator call on a hall call input panel). If the elevator car 4 begins to move even whilst the hoistway door 10c is open, the technician knows that the hoistway door switch 12c (which should prevent normal operation whilst the hoistway door 10c is open) is faulty and can investigate accordingly in step 306. However, if normal operation is successfully prevented, the technician can be confident in the operation of the hoistway door switch 12c and can proceed to step 308.

(22) In step 308, the technician enters (or reaches into) the hoistway 6, stepping (or reaching) onto the top of the elevator car 4, which is aligned with the first floor 8b. The technician toggles the emergency stop switch 18 (into a STOP position then into a GO position), and then operates the inspection switch 16 into the INSPECTION position.

(23) The elevator controller 22 continuously monitors the states of the hoistway door switches 12a, 12b, 12c, the inspection switch 16 and the emergency stop switch 18. Once the elevator controller 22 detects a change of state on all three of the switches involved, it will permit inspection mode operation. Thus with the inspection switch 16 in the INSPECTION position, it places the elevator system 2 into an inspection mode, in which the elevator inspection controls 14 may be used by the technician to control the elevator car 4.

(24) However, if the elevator controller 22 does not detect a change of state on all switches, it prevents inspection mode operation of the elevator car 4, even though the inspection switch 16 is in the INSPECTION position. Furthermore, if a change of state is detected on at least one but not all of the switches the elevator controller 22 may prevent all operation of the elevator car 4. Thus, all the relevant switches must be functioning correctly for the elevator system 2 to enter the inspection mode, and the technician can be confident that no unexpected elevator car 4 movement will occur. The method outlined with reference to FIG. 3 does not require the technician to exit and enter the hoistway or manually test the operation of the elevator system 2 several times. It is thus faster than conventional procedures (e.g. shown in FIG. 2) and cannot be bypassed by an untrained or forgetful technician.

(25) As discussed above, in some examples, the system may additionally check for changes of state in one or more of an up button, a down button and a command button of the elevator inspection controls which may be provided on top of the elevator car and may accordingly prevent inspection mode operation until such changes of state have been duly verified. Again this adds very little time to the process as a simple press or toggle of each switch is all that is required to verify that the buttons are operational.