BE1027980B1 - Elevator system - Google Patents

Abstract

Elevator installation (1), comprising at least one elevator shaft (20), at least one car (5) which is movably received in the elevator shaft (20), at least one first guide rail (22V) for guiding the elevator car (5) in the elevator shaft (20) ) along a first lane (2V), which is in particular aligned vertically, at least one second guide rail (22H) for guiding the car (5) in the elevator shaft (20) along a second lane (2H), which in particular is not aligned vertically, a transfer unit (30) comprising a rotatable frame (31) with a rotatable guide rail (22B) for transferring the car (5) from the first guide rail to the second guide rail, the transfer unit (30) having two rotatable frames (31o, 31u arranged one above the other) ) each comprising a rotatable rail (22B).

Description

Elevator installation Technical field The invention relates to an elevator installation.

TECHNICAL BACKGROUND DE 10 2014 220 966 A1 discloses an elevator installation in which several cars are operated cyclically in a circulating operation, similar to a paternoster.

In contrast to the classic paternoster, each car is driven independently of the other cars and can therefore stop at any stop independently of the other cars.

Transfer units are provided in order to transfer the cars from a vertical lane to a horizontal lane in order to ultimately transfer the cars between different vertical lanes.

The drive takes place using a linear drive.

The transfer units comprise rotatable rails.

WO 2017/174464 A1 discloses a drive unit for the transfer unit in such an elevator unit.

A bearing unit and an electric motor unit for driving the rotary movement are accommodated in a common assembly.

The drive unit has a total diameter of 800 m.

In a prototype implementation in the test tower in Rottweil, which was published in 2017, the diameter of the rolling element track in the bearing unit is around 0.5 m.

The not yet published DE 10 2019 210 529 suggests as a further development of the 0.g.

Elevator systems propose to significantly enlarge the storage unit of the conversion unit, in particular in order to be able to better absorb the forces and moments that occur during peak loads.

The as yet unpublished DE 10 2019 205 898 describes the relationship between the maximum drive power and the diameter of the bearing unit of the transfer arrangement in an aforementioned elevator system.

Accordingly, the number of stators on the car is basically maximized by the diameter of the rotating platform.

EP 3 409 631 A1 discloses an elevator installation which does not require guide rollers.

Instead, a magnet guide for the cabins is provided.

For this purpose, the elevator system has a plurality of stator beam parts arranged parallel to one another, in which the rotor parts (movers) are guided.

The linear drive thus formed also takes on the guiding function in addition to the pure drive function.

A plurality of parallel magnetic rails are provided for safe and comfortable guidance of the cabin using the magnetic guide. It is the object of the present invention to improve the aforementioned elevator systems. DISCLOSURE OF THE INVENTION The object on which the invention is based is achieved by an elevator system according to the main claim; Refinements are the subject of the subclaims and the description. Instead of providing the bearing with a significantly larger diameter (as suggested in DE 10 2019 210 529), the invention now achieves that the extension of the transfer unit is increased in the vertical direction, but no increase is required in the lateral direction.

It is thus possible that the greatest possible vertical length is available to accommodate stators, which - at least when using similar stators and rotors - is causal for a high drive power (see DE 10 2019 205 898). In order to achieve this, however, no widening of the elevator shaft is necessary, or this is not limited by the shaft width.

In one embodiment, the two rotatable frames can each be rotated about a first and second axis of rotation, which are not identical, but are arranged parallel to one another and spaced apart from one another.

In particular, the invention can be used if the car is mounted on a backpack. In the case of backpack storage, all guide rollers are in particular on one side of the car. The car is in particular supported in a cantilevered manner.

Furthermore, the costs of a bearing would increase disproportionately with its diameter. The use of two small bearings can therefore have a cost advantage. The invention can be used in particular in elevator systems with a shaft height in the first, in particular vertical, direction of at least 100 m, in particular at least 200 m. The invention can be used in particular in elevator systems with a maximum car speed of the car in the first, in particular vertical, direction of at least 6 m / s, in particular at least 8 m / s or 10 m / s.

z BE2019 / 5945 Brief description of the drawing The invention is explained in more detail below with reference to the figures.

In each case, FIG. 1 schematically shows a detail of an elevator installation according to the invention according to the prior art in a perspective illustration; FIG. 2 shows a cross-sectional representation of the linear drive 8 of the elevator installation according to FIG. 1 according to the section line II-II; FIG. 3-5 the transfer unit of an elevator installation according to the invention in a front view in a different situation; FIG. 6 shows the transfer unit of the elevator installation according to the invention in a side view with a cabin with vertically aligned movable rails; 7-8 holding arrangements for holding the rotating frame of the elevator installation according to the invention in different representations; FIG. 9 a holding frame of the elevator installation according to the invention in an individual illustration; FIG. 10 shows a rear view of the car of the elevator installation according to the invention.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows parts of an elevator installation 1, which is the starting point of the present invention.

The elevator installation 1 comprises a plurality of lanes 2H, 2VL, 2VR along which a plurality of cages 5 are guided.

There are several, here by way of example two, vertical lanes 2VL, 2VR aligned in a first direction z, along which the cages 5 can be moved between different floors.

Between the two vertical lanes 2VL, 2VR, horizontal lanes 2H are arranged in a second direction y, along which the cages 5 can each be moved within a floor.

Furthermore, the horizontal lane 2H connects the two vertical lanes 2VL, 2VR with one another.

Thus, the horizontal lane 2H also serves to transfer the cages 5 between the two vertical lanes 2VL, 2VR,

e.g. to run a modern paternoster operation. Further such horizontal lanes 2H are provided in the elevator installation 1, which connect the two vertical lanes with one another. Further vertical lanes, which are not shown, can also be provided.

Guide rails 22V, 22H, 22B for guiding the cages are provided along the lanes. Each lane comprises at least two separate guide rails 22 running parallel to one another. The cars 5 have guide rollers (not shown) for guidance on the rails.

The transfer arrangement 3 comprises, for example, two transfer units 30. Via the transfer units 30, the elevator car 5 can be transferred between the first vertical fixed guide rails and the second horizontal fixed guide rail. A transfer unit has a movable guide rail 22B, which in the present case is rotatable. In the present exemplary embodiment, the vertical direction and the horizontal direction are only an example of a first and second direction, respectively, as stated in the claims. All guide rails are installed at least indirectly on a shaft wall of the shaft 20. The cars are driven by a linear drive 8. The linear drive 8 comprises stators 81 which are fixedly arranged in the shaft along the travel lanes. The linear drive 8 comprises runners 82 which are arranged on the respective elevator cars 5. The stators 81 of a lane, viewed in the x direction, are arranged centrally between the guide rails 22 of this lane. Up to this point, the elevator system basically corresponds to what is described in WO 2015/144781 A1 and in DE10 2016 211 997A1 and DE 10 2015 218 025 A1. FIG. 2 shows details of the linear drive 8 in a cross-sectional representation corresponding to the section line II-I in FIG. 1. A rotor carrier 83 is provided on the elevator car 5, which surrounds the stator 81 in a U-shape, that is, from three sides. The rotor 82 is arranged here in the form of two rotor magnets 82M on two opposite legs 835. FIGS. 3 to 6 show an embodiment of a relocating unit 30 of an elevator installation according to the invention in a front view. This can be used in the elevator system according to FIG. 1 instead of the conversion unit 30 shown there, which results in an elevator system according to the invention.

The transfer unit 30 has two rotatable frames 31, namely an upper rotatable frame 310 and a lower frame 31u, which each include the movable rails 22B.

Each of the rotatable frames 310, 31u is selectively movable between an orientation in a first position (FIG. 3) or a second position (FIG. 5). The car 5 5 can move from the vertical first rail 22V (as the first rail) to the horizontal one

Rail 22H (as a second rail) can be implemented.

The specialty lies in the use of two rotatable frames 310, 31u, which are arranged adjacent to one another in the vertical direction z.

This enables the effective length L83, along which the rotor magnets are arranged on the rotor carrier 83, to correspond approximately to twice the diameter D31 of the rotatable frame 31.

The two rotatable frames 310, 31u are horizontally aligned with one another.

FIG. 6 shows details of the car 5 of the elevator installation according to the invention.

Deviating from the basic shape, which is described for example in WO 2015/144781 A1, the present car 5 comprises two slides, namely an upper slide 520 and a lower slide 52u, which are arranged vertically adjacent to one another.

The upper slide 520 carries the upper rotor support 830, the lower slide 52u supports the lower rotor support 83u.

The upper rotatable frame 310 is held rotatably on the shaft 20 by means of an upper frame pivot bearing 330 - at least indirectly; the lower rotatable rack 31u is held rotatably on the shaft 20 by means of a lower frame pivot bearing 33u - at least indirectly.

The frame pivot bearings 330, 33u define the alignment of the frame axis of rotation Ao, Au of the rotatable frames 310, 31u.

The distances DA of the frame axes of rotation Ao, Au of the rotatable frames 31 are identical to the distances DB of the carriage rotation axes Bo, Bu of the carriage 520, 52u.

For one

In the transfer process, the car is to be positioned on the transfer unit in such a way that both frame axes of rotation Ao, Au are arranged coaxially to the corresponding carriage rotation axes Bo, Bu.

The car 51 and the carriage 52 are part of the car 5. The car can have a car carrier which establishes the connection to the carriage, as in DE 10

2017 202 845 A1 shown.

During a relocation process, the upper carriage rotation axis Bo of the upper carriage rotation bearing 530 is coaxial with the upper frame rotation axis Bo of the upper rotatable one

To align frame 310 and the lower carriage axis of rotation Bu of the lower carriage pivot joint 53u is to be aligned coaxially to the frame axis of rotation Au of the lower rotatable frame 31u. Guide rollers 54 are attached to the carriage 520, 52u for guiding the respective carriage on the guide rails 22.

The division into two also results in a favorable lower support for the cabin. To explain the corresponding problem, reference is made to DE 10 2017 210 308 A1, which is achieved by providing a horizontal support in the lower area. In the present invention, the lower carriage takes over the function of such a lower horizontal support. In this way, the loads caused by the backpack storage can be better absorbed and diverted.

The rotary movement of the rotatable frames 310, 31u is driven by a common drive 60 (only shown in FIG. 3). This drive 60 has a motor 61 and a synchronization gear 62. With this, the rotatable frames 310, 31u are driven synchronously. For possible details of such transmissions, reference is made to DE 10 2019 201 511 A1 and DE 10 2019 213 622 A1 (both subsequently published), with the proviso that the transmission shown therein can drive both rotatable frames of the present description.

FIGS. 7 to 8 show parts of configurations of the elevator installation according to the invention in a front view. The frame pivot bearings 330, 33u for mounting the rotatable frames 31 can be seen. The rotatable frames themselves and all rails and the elevator car are not shown for better visibility. First, the different configurations are described together; This is followed by a description of the design-specific features.

The frame pivot bearings 33 are each fastened to the shaft 20 via a holding arrangement 7.

Each holding arrangement 7 comprises an adjustment arrangement 74 with, for example, a plurality of adjustment points 72 which are used to adjust the alignment of the respective frame pivot bearing 33. Basically, such an adjustment arrangement is already described in WO 20187149554 A1.

The frame pivot bearing is 33 is held by means of a holding frame 71. The holding frame 71 is held on the manhole via one or more manhole fastenings 72. The alignment of the holding frame 71 with respect to the shaft fastening can be changed via the adjustment arrangement 74. The holding frame 71 has high-precision manufactured contact surfaces 75 in which such a frame pivot bearing 33 is positioned in a defined manner. The possible shape of the

Contact surfaces 75, which define the position of the rotary bearing 33 in all three directions x, y and z, are shown schematically in FIG. 9 (without illustration of the frame rotary bearing) for the configuration of FIG. 7a. Analogously, the shape of the contact surfaces 75 can also be used in the configurations of the other figures.

In the embodiment according to FIG. 7 a, the upper frame swivel joint 330 is held by a first holding frame 710. The alignment of the upper holding frame 710 can be adjusted using an upper adjustment arrangement 740 with upper adjustment points 730. The lower frame swivel joint 33u is held by a separate lower holding frame 71u. The alignment of the lower holding frame 71u can be adjusted with the aid of a lower adjustment arrangement 74u with lower adjustment positions 73u. The attachment of the two frame pivot bearings 330, 33u to the shaft attachment and the setting of the two frame pivot bearings 330, 33u thus take place independently of one another.

In the embodiment according to FIG. 7 b, the upper frame swivel joint 330 is held by an upper holding frame 710. The alignment of the upper holding frame 710 can be adjusted using an upper adjustment arrangement 740 with upper adjustment points 730. The upper holding frame is connected to the manhole mountings as in FIG. 7a. The lower frame swivel joint 33u is held by a separate lower holding frame 71u, which, however, is fastened to the upper holding frame 710. The alignment of the lower holding frame 7u is consequently adjusted relative to the upper holding frame 710 with the aid of the lower setting arrangement 74u with the lower 9 setting points 73u.

In the embodiment according to FIG. 8 a, the upper frame swivel joint 330 and the lower frame swivel joint are held by a common holding frame 71. The alignment of the holding frame 71 is set via a common setting arrangement 74 with setting points 73. The holding frame 71 is connected to the manhole mountings 72. A relative adjustment of the upper frame pivot bearing 550 to the lower frame pivot bearing 55u is not provided. In order to ensure, however, upper contact surfaces 750 for contact of the upper frame pivot bearing 330 on the holding frame 71, and lower contact surfaces 750 for contact of the lower frame pivot bearing 33u on the holding frame 71 are manufactured with high precision with respect to one another. The required accuracy in the alignment of the upper and lower frame axes of rotation Ao, zo Au is consequently ensured by the accuracy in the holding frame 71 itself. The embodiment according to FIG. 8b is based entirely on the embodiment according to FIG. 8a. In contrast, the holding frame 71 is constructed in two parts and comprises an upper partial holding frame 710 and a lower partial holding frame 71u, which can be separated from one another at a separation point 76. The separation points 76 are also manufactured with high precision and allow a precise connection of the two sub-frames 710, 71u to one another. Fasteners 77 (e.g. screws, rivets, etc.) are provided in order to firmly connect the two sub-frames 710, 71u to one another. The divisibility, if necessary, has advantages during transport and during installation of the holding frame 71 in the shaft. Here, too, due to the small manufacturing tolerances, the upper contact surfaces 750 for contacting the upper frame pivot bearing 330 and lower contact surfaces 75u for contacting the lower frame pivot bearing 33u with one another within the specified small tolerances. FIG. 10 shows parts of an embodiment of the elevator installation according to the invention in a rear view.

This configuration can be combined with all configurations of the previous figures. The rear of the car 51 can be seen with the carriage pivot bearings 530, 53u, which are arranged between the respective carriage 520, 52u (not shown) and the car 51. The upper carriage pivot bearing 530 is designed as a fixed bearing. Thus, the position of the upper carriage rotation axis Bo of the upper carriage rotation bearing 530 is fixed with respect to the car 51. The lower carriage rotation bearing 53u is designed as a floating bearing. The position of the lower carriage rotation axis Bu of the lower carriage rotation bearing 53u is thus variable within predetermined limits, which is shown in FIG. 10 by the dashed circle around the lower carriage rotation axis Bu. This embodiment according to FIG. 10 can in particular be combined with that of the embodiment according to FIGS. 8a and 8b, which, due to the structure, require greater tolerances in the relative alignment of the frame axes of rotation Ao, Au. The larger tolerances are now supported on the cabin side, since the relative arrangement of the carriage axes of rotation Bo, Bu is variable within the aforementioned tolerances. When the car 5 moves into the transfer unit 30, it is first ensured that the upper carriage axis of rotation Bo is exactly aligned with the upper frame axis of rotation Ao. The lower carriage rotation axis Bu does not have to be precisely aligned with the lower frame rotation axis Au. The lower carriage rotation axis Bu can automatically align with the lower frame rotation axis Au due to the floating bearing 55u of the lower carriage rotation bearing 53u and thus compensate for the larger tolerances on the holding arrangement 7.

So that the car is held firmly in the shaft during the rotation of the rotatable rail despite the floating bearing (and does not wobble around), the car can be held firmly in relation to the shaft by means of a locking device (not shown).

Such a locking device and the associated method are described, for example, in WO 2018/091471 A1 (see there the second locking device 62, which is closed from FIG. 4). So that the linear output on the lower car can transmit the drive force to the car during the movement along the vertical and / or horizontal rail despite the floating bearing, the lower carriage can be fixed opposite the car if necessary.

In this way, the mobility shown with reference to FIG. 10 can be prevented.

Such a locking is described, for example, in WO 2018/091471 A1 (see there the first locking device 61, which is closed in FIG. 2). In the exemplary embodiment, the “upper” and “lower” components were used; The claims leave open at this point whether the upper lower component has a particular property and therefore speak of the first or second

Component.

This is because the particular properties of the respective upper or lower component mentioned in the exemplary embodiments can also be present on the respective other component (ie the lower or upper).

LIST OF REFERENCE SYMBOLS “© BE2019 / 5945 1 elevator system 2H horizontal lane 2VL, 2VR vertical lane 20 elevator shaft

22V first fixed guide rail vertical 22H second fixed guide rail horizontal 22B movable guide rail

30 Transfer unit 310 movable frame 310 movable frame above $ lu movable frame below 330 lower frame pivot bearing between rotatable frame above and shaft

33u upper frame pivot bearing between rotatable frame below and shaft 5 car 51 cabin 520 slide above 52u slide below

530 Upper carriage pivot bearing between upper carriage and cabin 53u lower carriage pivot bearing between lower carriage and cabin 54 guide rollers 550 fixed bearing 55u floating bearing

60 Drive 61 Motor 62 Synchronization gear

7 Holding arrangement 710 upper holding frame 71u lower holding frame 72 manhole fastening 73 adjustment points

2730 upper adjustment positions

73u lower adjustment positions 74 adjustment arrangement 740 upper adjustment arrangement 74u lower adjustment arrangement 75 contact surface

76 Cutting point 77 Connector

8 linear drive 81 stators 82 sliders 83 rotor carriers

A frame rotation axis of the rotatable frame B carriage rotation axis of the carriage 53C radially outer end of the movable rail D31 diameter rotating frame

L83 length of runner

Claims (18)

Claims 12 BE2019 / 5945 1. Elevator system (1), comprising at least one elevator shaft (20), at least one car (5) which is movably received in the elevator shaft (20), at least one first guide rail (22V) for guiding the car (5) in the elevator shaft (20) along a first lane (2V), which is in particular vertically aligned, at least one second guide rail (22H) for guiding the car (5) in the elevator shaft (20) along a second lane (2H), which in particular is not aligned vertically is, a transfer unit (30) comprising a rotatable frame (31) with a rotatable guide rail (22B) for transferring the car (5) from the first guide rail to the second guide rail, characterized in that the transfer unit (30) has two rotatable ones arranged one above the other Frame (310, 31u), in particular a first frame (310) and a separate second frame (31u), each with at least one rotatable rail (22B). 2. Elevator system according to the preceding claim, characterized in that guide rollers (54) are provided which are attached to the car (54) in such a way that the car (54) is guided on the guide rails (22) by the guide rollers (54). 3. Elevator installation according to one of the preceding claims, characterized in that a linear drive is provided for driving the elevator car. 4. Elevator system according to one of the preceding claims, characterized in that the linear drive has stators (81) fixedly arranged in the shaft and runners (82) arranged on the car, in particular wherein all stators of a lane (2VL, 2VR, 2H) along a single line are aligned, which is arranged centrally between the guide rails (22). 5. Elevator installation according to the preceding claim, characterized in that individual runners are arranged on the rotatable frame (31) and can be transferred together with the rotatable guide rails (22B) between an alignment in the first lane and an alignment in the second lane. 6. Elevator system according to one of the preceding claims, characterized in that the elevator system is set up so that the rotatable frames can be transferred together between a first position and a second position, the rotatable rails being aligned with the first lane in the first position, wherein in the second position the rotatable rails are aligned with the second lane. 7. Elevator system according to one of the preceding claims, characterized in that the elevator system is set up to transfer the first movable frame and the second movable frame synchronously between the first and the second position. 8. Elevator system according to one of the preceding claims, characterized in that the movement of the two rotatable frames (310, 31u) are coupled to one another by a synchronization gear (62). 9. Elevator installation according to one of the preceding claims, characterized in that the rotatable frames (310, 31u) each have at least two rotatable rails (22B) which are held parallel to one another on the rotatable frame. 10. Elevator installation according to one of the preceding claims, characterized in that the relocating unit (30) has exactly two rotatable frames (310, 32u) which are arranged one above the other and centered horizontally to one another and are set up, jointly transfer the car between the alignment in the first lane and the alignment in the second lane. 11. Elevator installation according to one of the preceding claims, characterized by a holding arrangement (7) for holding the rotatable frame (310, 31u), wherein the holding arrangement (7) has at least one adjustment arrangement (74, 740, 74u) for adjusting the orientation of the rotatable Frame and / or for adjusting the alignment of frame axes of rotation (Ao, Au) about which the rotatable frames are each rotatable, comprises. 12. Elevator installation according to claim 11, characterized in that the holding arrangement (7) comprises: a first setting arrangement (740) set up for setting the alignment of a first rotatable frame (310) and / or a first frame axis of rotation (Ao) about which the first rotatable frame (310) is rotatable, and a second adjustment arrangement (74u) for adjusting the orientation of a second rotatable frame (31u) and / or a second frame axis of rotation (Au) about which the second rotatable frame (31u) is rotatable (Figure 7 ); in particular that the first setting arrangement (740) and the second setting arrangement (74u) are set up so that the alignment of the first rotatable frame (310) or the first frame axis of rotation (Ao) and of the second rotatable frame (31u) or the second frame axis of rotation ( Au) can take place independently of one another with respect to the shaft (20) (FIG. 7a); or that the first setting arrangement (740) is set up so that the alignment of the first rotatable frame (310) or the first frame axis of rotation (Ao) can take place with respect to the shaft (20), and that the second setting arrangement (74u) is set up so that the alignment of the second rotatable frame (31u) or the second frame axis of rotation (Au) with respect to the alignment of the first rotatable frame (310) or the first frame axis of rotation (Ao) can take place (FIG. 7b). 13. Elevator system according to claim 11 or 12, characterized in that that the holding arrangement (7) comprises: a common setting arrangement (74) set up for synchronous setting - the alignment of a first rotatable frame (310) and / or a first frame axis of rotation (Ao) about which the first rotatable frame (310) is rotatable, and - the alignment of a second rotatable frame (31u) and / or a second frame axis of rotation (Au) about which the second rotatable frame (310) can be rotated (FIG. 8). 14. Elevator system according to one of claims 11 to 13, characterized in that the holding arrangement (7) comprises at least one holding frame (71) for holding at least one rotatable frame (31) with respect to the shaft, the orientation of the holding frame (71) via the Adjustment arrangement (74) is adjustable. 15. Elevator system according to one of claims 11 to 14, characterized in that the holding arrangement (7) comprises a first holding frame (710) and a second holding frame (71u) separate therefrom, the first holding frame (710) for holding the first rotatable frame (310) is set up, wherein the second holding frame (71u) is set up for holding the second rotatable frame (31u). 16. Elevator installation according to one of claims 11 to 15, characterized in that the holding arrangement (7) comprises a first common holding frame (71) for holding both rotatable frames (310); in particular that the common holding frame (71) is designed in several parts and comprises a first partial holding frame (710) and a second partial holding frame (71u) separate therefrom, the first partial holding frame (710) being set up to hold the first rotatable frame (310), the second Part holding frame (71u) is set up to hold the second rotatable frame (31u), the two part holding frames being firmly connected to one another by a releasable connection (76, 77). 17. Elevator system according to one of the preceding claims, characterized in that the car (51) comprises a car (51) and a first carriage (520) and a second carriage (52u) for guiding the car (51) along the guide rails, wherein the car (5) is set up, - that during a relocation process the first carriage (520) rotates around a first carriage rotation axis (Bo) which is coaxially aligned with a first frame rotation axis (Ao) around which the first movable frame (310 ) - that during a relocating process, the second carriage (52u) rotates around a second carriage rotation axis (Bu) which is coaxially aligned with a second frame rotation axis (Au) around which the second movable frame (31u) rotates. 18. Elevator system according to the preceding claim, characterized in that at least one of the carriage rotation axes (Bu) are mounted on the car (51) in a self-aligning manner; in particular that one of the carriage (52u), in particular the second carriage (52u), is supported by means of a floating bearing (55u) opposite the car (51), the floating bearing being set up to allow mobility of the carriage rotation axis (Bu) in relation to the car (51) ) to allow a predetermined first extent, in particular that the other carriage (520), in particular the first carriage (520), is mounted as a fixed bearing (550) opposite the cabin (51), the fixed bearing (550) being set up not to allow mobility of the carriage rotation axis (Bu) with respect to the cabin (51) or at least to allow it to a predetermined second extent, the second extent being smaller than the first extent.