EP2741990A1

EP2741990A1 - Low pit access detection and monitoring

Info

Publication number: EP2741990A1
Application number: EP11871060.7A
Authority: EP
Inventors: Gregor STRICKER; Gerard Sirigu; Ricardo CANO-TORRES
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 2011-08-12
Filing date: 2011-08-12
Publication date: 2014-06-18
Also published as: WO2013025185A1; EP2741990A4

Abstract

An elevator system includes a hoistway and an elevator car moveable along the hoistway. A drive system is located in the hoistway and is operably connected to the elevator car to urge movement of the elevator car along the hoistway. A safety system to establish a protected volume in the hoistway includes a prop installable in the hoistway to prevent downward movement of the elevator car and a plurality of relays configured to detect faults in the elevator control system to prevent movement of the elevator car prior to installation of the prop.

Description

LOW PIT ACCESS DETECTION AND MONITORING

BACKGROUND

[0001] The subject matter disclosed herein relates to elevator systems. More specifically, the subject disclosure relates to elevator systems having a shallow pit and/or a low overhead.

[0002] Elevator systems having a shallow pit and/or a low overhead, being part of so- called "machine room-less" elevator systems, have at least a portion of their drive systems such, as the motor and the brake, located inside of the hoistway of the elevator, where an elevator car travels. Such a construction typically provides construction cost savings and can be more compatible with severe architectural constraints than a traditional elevator system with a machine room and/or regular pits or overheads. Access to the systems located in the hoistway is required periodically for system maintenance and/or repair. As such, safety requires that the elevator car motion is stopped during this time, and that an amount of clearance is provided so that the maintenance and/or repairs can be accomplished.

[0003] Typically, the motor and brake are deactivated to stop motion of the elevator car in the hoistway.

SUMMARY

[0004] An embodiment of an elevator system includes a hoistway and an elevator car moveable along the hoistway. A drive system is located in the hoistway and is operably connected to the elevator car to urge movement of the elevator car along the hoistway. A safety system to establish a protected volume in the hoistway includes a prop installable in the hoistway to prevent downward movement of the elevator car and a plurality of relays configured to detect faults in the elevator control system to prevent movement of the elevator car prior to installation of the prop.

[0005] In another embodiment, the elevator system additionally or alternatively includes each relay of the plurality of relays being in electrical communication with one of a lower landing key switch or a lower landing door contact.

[0006] In another embodiment, the elevator system additionally or alternatively includes an incorrect position of one of the lower landing key switch or the lower landing door contact being indicative a fault in the elevator control system. [0007] In another embodiment, the elevator system additionally or alternatively includes the fault in the elevator control system tripping one or more of the plurality of relays, thereby deenergizing the drive system.

[0008] In another embodiment, the elevator system additionally or alternatively includes a remote station operably connected to the safety system and configured to detect additional elevator control system faults.

[0009] A method of preventing movement of an elevator car includes moving the elevator car to a selected position in an elevator system hoistway and opening a lower landing door to provide access to the hoistway beneath the elevator car. One or more faults in an elevator control system are detected via a plurality of relays. Unintended movement of the elevator car is prevented via detection of the one or more faults. A prop is erected in the hoistway to prevent movement of the elevator car.

[0010] In another embodiment, the method additionally or alternatively includes deenergizing a drive system of the elevator car upon detection of the one or more faults, thereby preventing the unintended movement of the elevator car.

[0011] In another embodiment, the method additionally or alternatively includes each relay of the plurality of relays being in electrical communication with one of a lower landing key switch or a lower landing door contact.

[0012] In another embodiment, the method additionally or alternatively includes an incorrect state of one of the lower landing key switch contacts or the lower landing door contacts being indicative of a fault in the elevator control system.

[0013] In another embodiment, the elevator system additionally or alternatively includes the fault in the elevator control system tripping one or more of the plurality of relays, thereby deenergizing the drive system of the elevator car.

[0014] In another embodiment, the elevator system additionally or alternatively includes detecting additional elevator control system faults via a remote station operably connected to the elevator control system.

[0015] These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

[0017] FIG. 1 is a schematic view of an embodiment of an elevator system; and

[0018] FIG. 2 is a schematic view of an embodiment of an electrical circuit for an elevator system.

[0019] The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION

[0020] Shown in FIG. 1 is an embodiment of an elevator system 10. The elevator system 10 includes an elevator car 12 moveably vertically in a hoistway 14 along, for example, one or more hoistway rails 16. The elevator car 12 is driven through the hoistway 14 by a machine 18. The machine 18 is connected to the elevator car 12 via one or more drive elements 20, which are cable, belts or the like. The elevator system 10 of FIG. 1 is a machine room-less elevator system 10. In such systems, the elevator car 12 moves essentially along an entire length of the hoistway 14, from a pit 22 located at a bottom of the hoistway 14 to an upper end 24 of the hoistway.

[0021] The system 10 is configured with a plurality of landings 26 along the hoistway 14. In the system 10 of FIG. 1, the machine 18 and other drive components are located at the pit 22 or in the overhead 24. They or other elevator components are accessible for maintenance and or repair via a lower landing 28, the lowest such landing 26 in the hoistway 14. To access the pit 22, and provide a suitable workplace for a mechanic to have access to elevator components, the elevator car 12 is moved to a maintenance limit 30 in the hoistway 14 or higher. Moving the elevator car 12 to the maintenance limit 30 or to a higher maintenance position is accomplished by entering an upwards call and then activating a lower key switch 32 located at the lower landing 28. Opening of the lower key switch 32 stops the elevator car 12 immediately and prevents further car 12 movement. The mechanic then opens a set of landing doors 34 at the lower landing 28 which opens landing door contacts 36. When the mechanic enters the pit 22 via the open lower landing doors 34, the mechanic erects a prop 38 or similar mechanical stop in the pit 22 to establish a protection volume 40 to protect the mechanic while in the pit 22. In the embodiment shown, the prop 38 is inserted into a receptacle in a floor 42 of the pit 22, and physically prevents further downward movement of the elevator car 12. [0022] Between the time the mechanic enters the pit 22 and the time the prop 36 is erected, however, a secondary safety measure is needed to prevent unwanted movement of the elevator car 12 before the prop 38 is erected. Such a safety measure is provided in the circuit of FIG. 2. The circuit of FIG. 2 is an addition to a safety chain 44, previously known in the art. The safety chain 44 can include bi- stable landing door key switches 32 for each landing 26, and it includes landing door contacts 36 for each set of landing doors 34. The key switches 32 and landing door contacts 36 are connected in such a way that an elevator operation control 46 cannot determine at which landing 26 the landing door contacts 36 are opened.

[0023] A sub-safety chain 46 is connected to the safety chain 44. The sub-safety chain 46 includes two pairs of relays 48 with positively driven contacts, the relay pairs 48 monitoring the key switch 32 contacts and landing door contacts 36 at the lower landing 28. In the event that a fault in one or more of the key switch contacts 32 and/or landing door contacts 36, such as a "stuck closed" fault, is indicated in a first relay 48, a second relay 48 is deenergized thereby deenergizing the machine 18 and other drive components of the elevator system 10 to prevent movement of the elevator car 12.

[0024] Further, the sub-safety chain 46 is connected to a remote station 50. The remote station 50 is configured to detect additional fault states, such as a fault state where the key switch 32 is indicated as "closed", but the lower landing door contacts 36 are indicated as "open". Such a state is an impossibility since the key switch 32 must be opened before the landing door contacts 36 may be opened. As above, detection of such a fault results in stopping operation of the machine 18 and other drive components of the elevator system 10 to prevent movement of the elevator car 12 and thereby protect a mechanic entering the hoistway 14 from injury.

[0025] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

CLAIMS:

1. An elevator system comprising:

a hoistway;

an elevator car moveable along the hoistway;

a drive system disposed in the hoistway and operably connected to the elevator car configured to urge movement of the elevator car along the hoistway;

a safety system to establish a protected volume in the hoistway including: a prop installable in the hoistway to prevent downward movement of the elevator car; and

a plurality of relays configured to detect faults in the elevator control system to prevent movement of the elevator car prior to installation of the prop.

2. The elevator system of Claim 1, wherein each relay of the plurality of relays is in electrical communication with one of a lower landing key switch contacts or a lower landing door contact.

3. The elevator system of Claim 2, wherein an incorrect state of one of the lower landing key switch or the lower landing door contact indicates a fault in the elevator control system.

4. The elevator system of Claim 3, wherein the fault in the elevator control system trips one or more of the plurality of relays, thereby deenergizing the drive system.

5. The system of Claim 1, further comprising a remote station operably connected to the safety system and configured to detect additional elevator control system faults.

6. A method of preventing movement of an elevator car comprising:

moving the elevator car to a selected position in an elevator system hoistway other than a lower landing position;

opening a lower landing door to provide access to the hoistway beneath the elevator car;

detecting one or more faults in an elevator control system via a plurality of relays;

preventing unintended movement of the elevator car via detection of the one or more faults; and

erecting a prop in the hoistway to prevent movement of the elevator car.

7. The method of Claim 6, further comprising deenergizing a drive system of the elevator car upon detection of the one or more faults, thereby preventing the unintended movement of the elevator car.

8. The method of Claim 6, wherein each relay of the plurality of relays is in electrical communication with one of a lower landing key switch or a lower landing door contact.

9. The method of Claim 8, wherein an incorrect state of one of the lower landing key switch contacts or the lower landing door contacts indicates a fault in the elevator control system.

10. The method of Claim 9, wherein the fault in the elevator control system trips on or more of the plurality of relays, thereby deenergizing the drive system of the elevator car.

11. The method of Claim 6, further comprising detecting additional elevator control system faults via a remote station operably connected to the elevator control system.