Clearance limiter for elevator car

Abstract

 The present invention relates to an elevator installation comprising an elevator car (2) having at least one clearance limiter (30) permanently projecting outwards from the car (2). The clearance limiter (30) partially bridges a gap (G) between the car (2) and a shaft wall (12) and therefore decreases the likelihood of service personnel falling through the gap into the shaft (10).

Description

[0001] The invention relates to an elevator installation and in particular to an elevator installation having an elevator car with a clearance limiter projecting therefrom to ensure the safety of service personnel working from the car roof.

[0002] It is common practice within the elevator field for service personnel to use the roof of an elevator car as a working platform during installation, commission, maintenance and inspection procedures. The frequency of this practice has increased significantly in recent years due primarily to the higher prevalence of machine-room-less installations whereby elevator components which where traditionally housed in a dedicated, separate machine room are now fully incorporated within the elevator hoistway.

[0003] As shown in Fig. 1, a balustrade 20 is normally installed on the car roof 4 to surround the car roof 4 and thereby ensure the safety of the service personnel and specifically to prevent them from falling through a gap G between the car 2 and the shaft walls 12 into the elevator shaft 10. The balustrade 20 can be permanently erected on top of the car roof 4 or can be collapsible as described in EP-A1-1422185. In either case, the balustrade 20 and its arrangement on the car roof 4 must comply with local regulations such as the ASME A17.1-2000 safety code for the United Stated of America or the EN 81-1:1998 standard throughout Europe. For example, the former of these two regulations requires that:

• the balustrade 20 must have a minimum height B of at least 1070 mm;
• with the car 4 in its uppermost position, as shown, there must be a 150 mm vertical clearance C between the upper rail of the balustrade 20 and the lowest part of the ceiling 14 (including any beam 16 or any other fixed component located under the ceiling 14); and
• a refuge space R having an unobstructed horizontal area of not less than 0.5 m² and an unobstructed vertical height of 1100 mm must be provided within the balustrade 20.

[0004] In order to satisfy all of these conditions, the overall clearance between the car roof 4 and the ceiling 14 of the shaft 10 is relatively large.

[0005] Furthermore, although the service personnel can work relatively freely within the area defined by the balustrade 20, a large proportion of the elevator components requiring maintenance such as the drive and the control are commonly located outside of the area defined by balustrade 20 and as such the balustrade 20 can severely hamper the service personnel when working on those components. Not only does this lead to an increase in the time and thereby the cost of maintenance and servicing operations but also frustrates the service personnel carrying out these tasks.

[0006] The collapsible balustrade 20 as described in EP-A1-1422185 is folded inwardly on top of the car roof 4 when not is use. This folding structure is complicated and therefore relatively expensive. Furthermore, it takes time for the service personnel to erect the balustrade 20 before they can commence their maintenance tasks.

[0007] When in its folded or stored position, the railings of the balustrade 20 crisscross the roof 4 making it at least difficult, if not impossible, to provide an effective emergency trap door in the car roof 4 to permit the rescue and evacuation of passengers.

[0008] The objective of the present is to overcome the problems associated with the prior art by providing an elevator installation comprising an elevator car having at least one clearance limiter permanently projecting outwards from the car.

[0009] Accordingly, the clearance limiter partially bridges a gap between the car and a shaft wall and therefore decreases the likelihood of service personnel falling through the gap into the shaft. Additionally, since the clearance limiter does not project upwards from the car, the overall vertical clearance between the car roof and the shaft ceiling can be reduced. As there is no physical vertical barrier, service personnel can work relatively freely from the top of the car with easier access to components mounted on the shaft walls. Furthermore, the clearance limiter effectively increases the size of the work area on top of the car. As the clearance limiter does not obstruct the exposed surface of the car roof, it is possible to provide an emergency trap door therein to permit the rescue and evacuation of passengers.

[0010] Preferably, the clearance limiter is fastened to a top of the car roof. Since there are no space restrictions on the car roof, the clearance limiter can be secured in place relatively easily during initial installation of the elevator.

[0011] The invention also provides a method for installing an elevator car in an elevator shaft comprising the steps of determining that a gap between the car and at least one of the shaft walls is or will be greater than a predetermined limit and providing a clearance limiter on the car to partially bridge the gap. This method is particularly useful in the modernization of an existing elevator installation wherein a standard car is installed in an existing shaft.

[0012] Preferably, a gap between the clearance limiter and a neighbouring shaft wall is less than 300 mm.

[0013] The present invention is hereinafter described by way of specific examples with reference to the accompanying drawings in which:

Figure 1 is a sectional view of an prior art elevator installation incorporating a conventional balustrade mounted on top of an elevator car;

Figure 2 corresponds to Fig. 1 but shows an elevator car incorporating a clearance limiter according to the present invention;

Figure 3 is a cross-section showing the clearance limiter or Fig. 2 in more detail;

Figure 4 is a cross-section of a clearance limiter according to a second embodiment of the invention;

Figure 5 is a cross-section of a clearance limiter according to a third embodiment of the invention;

Figure 6 is a cross-section of a clearance limiter according to a fourth embodiment of the invention; and

Figure 7 is a plan view of an elevator car incorporating a clearance limiter according to any preceding embodiment.

[0014] In the following description, for the avoidance of unnecessary repetition, features of the invention which are common to more than one embodiment have been assigned a common reference numeral and where appropriate share a common description.

[0015] As previously discussed, Fig. 1 is a sectional view of an upper portion of an elevator shaft 10 accommodating an elevator car 2 with a conventional safety balustrade 20 to prevent service personnel working on the car roof 4 from falling through a gap G between a car wall 6 and its neighbouring shaft wall 12. The overall clearance between the car roof 4 and the ceiling 14 of the shaft 10 is relatively large because the balustrade 20, in order to fulfil the conditions of legal regulations, must have a certain minimum height B and there must also be a specific vertical clearance C between an upper rail of the balustrade 20 and the lowest part of the ceiling 14 (including any beam 16 or any other fixed component located under the ceiling 14).

[0016] A first embodiment of the present invention is clearly shown in Fig. 2 where the balustrade 20 of the prior art is replaced by a clearance limiter in the form of a roof extension 30 which projects horizontally from the car roof 4. The reduced gap G' between the roof extension 30 and the shaft wall 12 is much smaller than the gap G between the car wall 6 and the neighbouring shaft wall 12. Therefore, the risk to service personnel of falling into the shaft 10 through the reduced gap G' is significantly decreased.

[0017] In addition to providing the same requisite refuge space R, the only other pertinent regulatory requirement with which the elevator installation must comply is to provide a minimum vertical overhead clearance T between car roof 4 and the lowest part of the ceiling 14 (including any beam 16 or any other fixed component located under the ceiling 14). Since this minimum clearance T is generally much smaller than the minimum balustrade height B there can be a significant reduction S in the overall height of the shaft 10. In the ASME safety code, for example, the value for T is quoted as 600 mm.

[0018] Applying the ASME safety code requirements to the arrangements shown in Figs. 1 and 2 for illustrative purposes and assuming the beam 16 has a height of 500 mm, then the actual vertical distance between the car roof 4 and the ceiling 14 for the arrangement of Fig. 1 is 1720 mm (the sum of B, C and 500 mm) whereas the actual vertical distance between the car roof 4 and the ceiling 14 for the arrangement of Fig. 2 is 1100 mm (the greater of the vertical dimension of the refuge space R or the sum of T+500). Accordingly, the invention provides a shaft height reduction R of 620 mm.

[0019] Even in a scenario in which no beam 16 or any other fixed component is located under the ceiling 14, the prior art still requires a clearance of 1220 mm (B + C), whereas the invention requires 1100 mm (vertical dimension of the refuge space R).

[0020] Hence, the invention reduces the overall clearance between the car roof 4 and the shaft ceiling 14 and thereby improves the space utilization of the elevator installation enabling the building owner to make commercial use of the space saved.

[0021] Fig. 3 shows the roof extension 30 of Fig. 2 in greater detail. The car roof 4 is prefabricated with a cavity 34 to accommodate the roof extension 30. On installation, the roof extension 30 is withdrawn from the cavity 34 to give the required gap or clearance G' between it and the neighbouring shaft wall 12 and is permanently secured in this position by any suitable fastening means such as screws 32. Preferably, a toe guard 44 is mounted along a side of the roof extension 30 that is remote from the car roof 4.

[0022] Fig. 4 shows a second embodiment of the present invention where the clearance limiter is a roof overhang 36. The overhang 36 is permanently fastened to the car roof 4 by suitable means such as screws 32. The overhang 36 comprises an upper sheet 36' which partially overlaps and is secured to the car roof 4 and a main body portion 36" suspended from the upper plate 36'. The main body portion 36" and upper sheet 36' conform to the corner of the car roof 4 and thereby help to resist any bending moment when a load is placed on the overhang 36. Alternatively, the overhang may consist of a simple metal sheet secured to the car roof 4 and projecting towards the shaft wall 12.

[0023] An important advantage of the clearance limiters of Figs. 3 and 4 is that on installation of the elevator they can be secured in place relatively easily from the car roof 4.

[0024] Fig. 5 illustrates a further embodiment wherein the clearance limiter is a bracket structure 38 secured to the car roof 4. The structure 38 comprises a plurality of vertical brackets 38" connected to a horizontal upper surface 38'. The brackets 38" are secured to the car roof 4 by any suitable means such as screws 32. Alternatively, the brackets 38" can be secured to the side wall 6 of the car 2.

[0025] Fig. 6 depicts a fourth embodiment of the invention where the car roof 4 is prefabricated to have a horizontal area greater than that defined by the car walls 6 where the section 40 that projects beyond the car wall 6 acts as the clearance limiter.

[0026] Figure 7 is a plan view of an elevator car incorporating a clearance limiter 30, 36, 38, 40 according to any of the previously described embodiments. Preferably, the clearance limiter 30, 36, 38, 40 has a meshed horizontally projecting surface 42 to reduce the material cost, weight and dynamic drag. Furthermore, the toe guard 44 may extend along the entire combined outer perimeter of the roof 4 and the clearance limiter 30, 36, 38, 40 to define the working platform and to prevent any loose items of equipment resting on the roof or on the clearance limiter from accidentally falling into the shaft 10 while the service personnel are working on the platform.

[0027] The invention is particularly, through not exclusively, useful in the modernization of an old elevator installation wherein a standard car 2 is installed in an existing shaft 10. The equipment used in older elevator installations tended to be much more bulky than those currently used today and accordingly, the existing shaft 10 will generally have a much greater cross-sectional area than is actually required to for the new elevator car 2. In such a case, rather than installing a balustrade 20 according to the prior art, the designer would determine whether the gap G between the car 2 and at least one of the shaft walls 12 is (if the car 2 has already been installed in the shaft 10) or will be (prior to the installation) greater than a predetermined limit and, if so, provide a clearance limiter 30,36,37,40 on the car 2 to partially bridge the gap G.

[0028] For convenience the invention has been described and depicted in each embodiment with a single clearance limiter, but it will be readily understood that clearance limiters can be mounted at other sides of the car to partially bridge the gap G between the car and the neighbouring walls.

Claims

1. An elevator installation comprising an elevator car (2) CHARACTERISED BY at least one clearance limiter (30,36,37,40) permanently projecting outwards from the car (2).

2. An elevator installation according to claim 1, wherein the clearance limiter (30,36) is fastened to a top of a car roof (4).

3. An elevator installation according to claim 1 or claim 2, wherein the clearance limiter (30) telescopes from a cavity (34) in a car roof (4) for fixation in its permanent position.

4. An elevator installation according to claim 2, wherein the clearance limiter is an overhang (36) comprising an upper sheet (36') overlapping the car roof (4) and a main body portion (36") suspended from the sheet (36') wherein the main body portion (36") and the upper sheet (36') conform to a corner of the car roof (4).

5. An elevator installation according to claim 1, wherein the clearance limiter (40) is integral with a car roof (4) which is prefabricated to extend beyond an area defined by the car walls (6).

6. An elevator installation according to claim 1, wherein the clearance limiter is a bracket structure (38) comprising a plurality of vertical brackets (38") secured to the car (2) and connected to a horizontal upper surface (38').

7. An elevator installation according to any preceding claim further comprising a toe guard (44) extending along an entire combined periphery of a car roof (4) and the clearance limiter (30,36,37,40).

8. An elevator installation according to any preceding claim wherein the clearance limiter (30,36,38,40) has a meshed horizontally projecting surface (42).

9. A method for installing an elevator car (2) in an elevator shaft (10) comprising the steps of determining that a gap (G) between the car (2) and at least one of the shaft walls (12) is or will be greater than a predetermined limit and CHARACTERISED BY providing a clearance limiter (30,36,37,40) on the car (2) to partially bridge the gap (G).

10. A method according to claim 9 further comprising the step of dimensioning the clearance limiter (30,36,37,40) so that a gap (G') between it and the neighbouring shaft wall (12) is less than 300 mm.

Drawing