The present invention relates to an elevator being provided with a safety device arrangement, more specifically an ar- rangement as defined in the preamble of claim 1 for prevent ing an elevator car from trapping or crushing a serviceper- son or fitter who is working in a shaft pit.

The service and maintenance work in the shaft pit may con- tain for example service or maintenance work for machinery, which term machinery later in this application text covers, in addition to the hoisting motor, also drives, traction members, such as ropes or belts, and brakes of the elevator. Also, other service and maintenance work than service and maintenance work for machinery, e.g. service and maintenance work for devices in an elevator car bottom, counter or bal ancing weight and overspeed governor or its related devices, are made in the shaft pit. Elevator fitters, who install, maintain or service elevators in the elevator shaft pit are subject to high risk of being trapped or, in a worst-case scenario, being crushed by an elevator car. If the elevator loses a control in a downward direction, and if no proper safety mechanisms are in place to provide a safe working space in the elevator shaft pit, the fitter entering or working in the pit could be subjected to serious and a potentially fatal injury or even death.

Usually the elevator shaft is provided with mechanical safe- ty devices that can be set up relating to the service work carried out in the elevator shaft to ensure a sufficient safety space in the elevator shaft pit. Some elevators pro vide pipe stands or rubber or spring buffers in the shaft pit below the elevator car to prevent the elevator car from falling to the bottom of the pit. These buffers may be e.g. turnable or movable or fixed buffers. The difficulties with using pipe stands or rubber or spring buffers are that they are often stored away from the elevator, and in the case of a heavy elevator car, they can weigh tens of kilograms in order to provide sufficient protection to the fitter. These factors can make it difficult or impossible for a fitter to service an elevator. In addition, there is a period of time when a pipe stand is being assembled in the elevator pit where the worker is unprotected against elevator cars that lose control in the down direction. Besides, the new Europe an regulation EN 81-20 also sets the prerequisite, that an elevator has to comprise a fixed mechanical device which provides at least 2 meters high free open space between the elevator car and the bottom of the shaft pit.

The protecting space in the shaft pit can also be implement ed by technical safety devices instead of a fixed or turna ble or movable buffers. From EP1118574 is known that a safe ty brake device, also known as a safety gear device, is de liberately actuated/triggered providing adequate safety space to the fitter, before he/she enters to the elevator shaft pit. Also, when the lower landing door of the elevator is opened manually to the shaft, the safety gear device is automatically released, blocking the elevator movement. The problem in the solution presented above is, that the safety gear device needs to be actuated/triggered every time the service is going to be made in the shaft pit. The safety gear unreleasing requires additional working efforts and sometimes triggering the safety gear may damage the guide rails. In addition, known maintenance solutions are inflexi ble, since solutions keep always the elevator car within the predefined minimum safety distance from the pit bottom and the fitter cannot e.g. deliberately drive the car for ser vice purposes below the predefined safety limits.

The object of the present invention is to eliminate the drawbacks described above and to achieve an elevator provid ed with a reliable and inexpensive safety device arrange ment. The present invention is also targeted to achieve an improvement for elevator arrangement with safety space in the shaft pit for maintenance operations. And yet another objective of the present invention is to achieve a safety arrangement that is operationally extremely reliable, easy and fast to use, and that immediately prevents the movement of the elevator car if the elevator loses control in the down direction. In the present invention, the safety space in the elevator shaft pit is achieved by utilizing other ex isting elevator safety components, like a safety circuit, an overspeed governor (OSG) and a safety gear and an actuator connected to the OSG. In the invention these are operated using the elevator control system and additional safety lim it detector arrangement, such as pit inspection mode limit switches. The elevator provided with the safety device ar rangement according to the invention is characterized by what is presented in the characterization part of claim 1. Other embodiments of the invention are characterized by what is presented in the other claims. Some inventive embodiments are also discussed in the descriptive section of the present application .

The inventive content of the application can also be defined differently than in the claims presented below. The in ventive content may also consist of several separate inven tions, especially if the invention is considered in the light of expressions or implicit sub-tasks or from the point of view of advantages or categories of advantages achieved. In this case, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts. Likewise, the different details present ed in connection with each embodiment can also be applied in other embodiments. In addition, it can be stated that at least some of the sub claims can, in at least some situa tions, be deemed to be inventive in their own right.

In order to achieve the objectives mentioned above, the pre sent invention provides an elevator provided with a safety device arrangement, which elevator comprises at least an el evator car traveling along guide rails in a shaft having a shaft pit, a machinery, a safety gear for stopping the ele vator car, as well as an overspeed governor, for activating the safety gear, an actuator device of the overspeed gover nor, an elevator control system, a safety circuit, a safety limit detector arrangement and a pit inspection mode. Advan tageously the safety device arrangement according to the in vention comprises different pit inspection sub-modes.

Preferably the safety device arrangement according to the invention comprises three different pit inspection sub-modes that can be selected with a pit inspection mode selector situated in the elevator car below the floor of the elevator car or on the roof of the elevator car.

Since the arrangement according to the invention utilizes existing elevator safety devices and components in a smart and novel way, it has the advantage among other things that it provides simple and cost-effective construction that saves a lot of time in an installation phase. It also cre ates reliable, safe and flexible working space in the eleva tor shaft pit for the fitter, which fulfills all necessary regulations. Thanks to reliable safety devices combined with a bulletproof safety process, the arrangement according to the invention improves working safety of maintenance persons in the shaft pit. In the following, the invention will be described in detail by the aid of an example by referring to the attached sim plified and diagrammatic drawings, wherein

Fig . 1 presents a flow chart of an elevator safety process of the maintenance work in an elevator shaft pit,

Fig . 2 presents in a simplified and diagrammatic side view an elevator shaft where an elevator car is in the second lowest floor level and a fitter is selecting a pit inspection sub-mode with a pit inspection mode selector according to the invention,

Fig . 3 presents in a simplified and diagrammatic top view the pit inspection mode selector according to the invention,

Fig . 4 presents in a simplified and diagrammatic side view an elevator shaft in a process step S4 of the in vention where a fitter is working with a machinery and with other components in the shaft pit under the elevator car,

Fig. 5 presents in a simplified and diagrammatic side view an elevator shaft in the situation where a safety gear has been activated, blocking the elevator car to guide rails during the service or maintenance work according to Figure 4, and Fig. 6 presents in a simplified and diagrammatic side view an elevator shaft in a process step S4 where a fit ter is working with other components than the ma chinery of the elevator.

The main focus of the invention is to present an elevator provided with a safety device arrangement, which arrangement utilizes existing elevator safety devices and components for easier, safer and more reliable safety solution for elevator maintenance work in the elevator shaft pit 19. The basic need is to ensure a safe working environment to elevator service persons, such as fitters 17, which environment ful fills all necessary safety regulations. On the other hand, the need is also to achieve a flexible environment enabling different kind of elevator service tasks.

Figure 1 presents a flow chart of the elevator safety pro cess of the maintenance work according to the invention in an elevator shaft pit 19. Figure 2 presents in a simplified and diagrammatic side view an elevator shaft 4 where an ele vator car 1 is in the second lowest floor and a fitter 17 is selecting a pit inspection sub-mode with a pit inspection mode selector 9.

The flow chart presents six-step safety process S1-S6 for serving or maintaining the elevator in the elevator shaft pit 19. When carrying out the elevator maintenance work, the elevator is set to the maintenance mode, also called inspec tion mode, which prevents the normal use of the elevator and, for instance, calling the elevator car 1 from landing levels. Also landing doors cannot be open and an access to the elevator shaft 4 is prevented. However, in that case the landing doors can be opened by a special key, for instance with a so-called triangle key. There are other more specific maintenance modes as well, like the pit inspection mode. Hatched boxes in the flow chart process steps indicate, that the elevator mode changes.

In process step SI, before elevator maintenance actions, the fitter 17 drives the elevator car 1 preferably to the second lowest level, so the elevator car 1 is not blocking the en trance to the shaft pit from the lowest floor level 15. The second level limit switch 13b indicates when the elevator reaches the second floor level and the elevator control sys tem parks the elevator car 1 in the correct position to the second floor level.

In process step S2, the fitter 17 opens the maintenance ac cess panel (MAP) 16, which usually locates in the lowest level 15 and switches the elevator to the inspection mode from the main access panel 16.

In process step S3, the fitter uses his/her special key to open the landing door 14 of the lowest level 15. When the fitter opens the lowest landing door 14 manually and so ena bles the access to the elevator shaft 4, the elevator system sets the elevator automatically to a pit inspection mode. The pit inspection mode restricts elevator car 1 from moving and driving so, that the elevator car 1 can be moved only from the pit inspection station 18, which is located in the elevator shaft pit 19. Once the lowest level landing door 14 has been opened, the fitter 17 can see the elevator car 1 in the elevator shaft staying at the second lowest level. The fitter also reaches to the pit inspection mode selector 9, which is located in the elevator car 1, fastened in an ap propriate place below the elevator car 1. Preferably the pit inspection mode selector 9 is fastened, for instance, at the lower end of a toe guard 3 between the elevator car 1 and the threshold of the landing doors of the elevator. Addi tionally, another pit inspection mode selector 9 is located on the elevator car 1 roof or near the roof of the elevator car 1.

Figure 3 presents in a simplified and diagrammatic front view one advantageous pit inspection mode selector 9 accord ing to the invention. The pit inspection mode selector 9 comprises a selector switch 9a with three switch positions: mO for a normal mode, ml for a blocking device mode and m2 for a normal pit inspection mode.

The fitter 17 selects/activates the desired pit inspection sub-mode ml, m2 with the pit inspection mode selector 9. By default, the normal mode mO is selected; this means that no inspection sub-mode ml, m2 is selected. Next the fitter 17 steps to the shaft pit 19, if necessary using ladders or fixed steps, and uses a pit control station 18 to drive the elevator car 1 to a desired position, normally to a pit in spection limit. The safety limit detector arrangement 11 in dicates when the elevator car 1 is at the pit inspection limit and stops the elevator car 1. Preferably the safety limit detector arrangement 11 comprises an elevator car 1 limit switch trigger 11a and a pit inspection limit switch lib. In other embodiments of the safety limit detector ar rangement 11 for example varying sensor and safety-buss so lutions may be applied. When the elevator car 1 is in the pit inspection limit the distance from the elevator car 1 to the floor of the shaft pit 19 is more than two meters and the gap between the bottom edge of the elevator and the low est level 15 floor is the minimum 700 millimeters to provide adequate access for the fitter 17 to the elevator shaft pit In process step S4, the fitter 17 begins working in the shaft pit 19. Earlier, the fitter 17 has selected with the pit inspection mode selector 9 the desired pit inspection sub-mode, either ml or m2.

Figure 4 presents in a simplified and diagrammatic side view an elevator shaft 4 in process step S4 where a fitter 17 is working with the machinery 5 of the elevator and the pit in spection sub-mode is set to a blocking device mode ml.

The blocking device mode ml is meant for service or mainte nance work for machinery 5 of the elevator. By selecting the blocking device mode ml with the pit inspection mode selec tor 9, the following additional safety functions happens: elevator safety circuit opens, which cuts the electricity from the elevator drive system which further disables the elevator car 1 from moving by using the car buttons or the landing buttons, the actuator device of the overspeed gover nor 7 activates, which activates the overspeed governor 7 to trigger the safety gear 8 immediately if unexpected movement of the elevator car 1 happens. The safety circuit function could be carried out also using other devices than a conven tional safety circuit. Triggering the safety gear 8 stops the elevator car 1 movement after the movement of 200 milli meters at maximum by locking the elevator car 1 to the guide rails 6 of the elevator. After the maintenance work is done, the fitter 17 leaves the shaft pit 19 and deactivates the blocking device mode ml back to normal mode mO with the pit inspection mode selector 9.

This embodiment of the elevator system comprises a bi directional overspeed governor 7 equipped with an actuator device. The overspeed governor 7 is fastened to the elevator car 1. A toothed belt 10, which is assembled vertically in the elevator shaft 4 from the roof to floor, goes through the overspeed governor 7 and rotates the wheel of the over speed governor 7 when the elevator car 1 is moving. If ele vator is over speeding, the wheel spins fast triggering au tomatically the bi-directional safety gear 8, which stops the elevator car 1 to the guide rails 6. The actuator device of the overspeed governor 7 can be activated and deactivated when needed. If the actuator device is activated, the over speed governor 7 triggers the safety gear 8 immediately if the wheel of the overspeed governor 7 is rotating regardless of the speed of rotation, i.e. if the elevator car 1 is mov ing even slightly. The elevator car 1 is blocked to the guide rails 6 after the movement of 200 millimeters at maxi mum .

Figure 5 presents in a simplified and diagrammatic side view an elevator shaft 4 in the situation when something went wrong in the maintenance situation and the elevator car 1 started to move downwards. The actuator device of the acti vated overspeed governor 7 has launched the overspeed gover nor 7 to trigger the safety gear 8, which blocked the eleva tor car 1 to guide rails 6 in service or maintenance work according to Figure 4. Figure 6 presents in a simplified and diagrammatic side view an elevator shaft 4 in process step S4 where a fitter 17 is working with other components than machinery 5 and the pit inspection sub-mode is set to m2.

A normal pit inspection mode m2 is meant for any other kind of work than a service or maintenance work for the machinery 5. By selecting the normal pit inspection mode m2 by the pit inspection mode selector 9, the following additional safety related functions happen: the elevator control bypasses the signal of the safety limit detector arrangement 11. In that case driving of the elevator car 1 using the pit control station 18 can be continued also below the height defined by the safety limit detector arrangement 11. This arrangement is necessary, since sometimes the service or maintenance work requires elevator car 1 to move below the pit inspec tion limit. In these cases, additional safety arrangements, like movable buffers, can be used to achieve required safety space for the fitter 17. The fitter 17 has driven the eleva tor car 1 to the lowest level limit switch 13a for the ser vice or maintenance work e.g. in the elevator car bottom. After the maintenance work is done, the fitter 17 leaves the shaft pit 19 and deactivates the normal pit inspection mode m2 back to normal mode mO with the pit inspection mode se lector 9.

In process step S5, when all the service/maintenance work in the shaft pit 19 is done, the fitter 17 closes the landing door 14 of the lowest level 15.

In process step S6, after all service/maintenance work for the whole elevator is done, the fitter 17 deactivates the inspection mode from the maintenance access panel 16 and the elevator is set to the normal operation mode.

It is obvious to the person skilled in the art that the in vention is not restricted to the example described above but that it may be varied within the scope of the claims pre sented below. Thus, for example, the elevator inspection modes may differ from what is explained above.

It is also obvious to the person skilled in the art that the shape and structure of the safety mechanism in the overspeed governor and safety gear can vary. For example, the over speed governor, safety gear triggering mechanism and safety gear mechanism can also vary. The safety switching with the circuit-breaker and trigger mechanism can be for example any kind of a suitable commercially available safety switch. And in addition, the overspeed governor and the safety gear do not need to be bi-directional. It is sufficient that they are set to stop the downward movement of the elevator car.