EP4282729A1

EP4282729A1 - Shoe assembly for supporting at least a supporting cable of an aerial cable transportation system, aerial cable transportation system comprising such a shoe assembly and method for operating such an aerial cable transportation system

Info

Publication number: EP4282729A1
Application number: EP23174450.9A
Authority: EP
Inventors: Alexander Pechlaner; Michael WURZER; Nikolaus Erharter
Original assignee: Leitner AG
Current assignee: Leitner AG
Priority date: 2022-05-23
Filing date: 2023-05-22
Publication date: 2023-11-29
Also published as: IT202200010649A1

Abstract

A shoe assembly (4) for an aerial cable transportation system (1) comprising at least one supporting cable (2) and at least one transport unit (3) moved on the supporting cable (2); wherein the shoe assembly (4) comprises: an inlet (5); an outlet (6); at least one seat (7) extending from the inlet (5) to the outlet (6) to support the at least one supporting cable (2); at least one safety device (8) to hold the at least one supporting cable (2) at the corresponding at least one seat (7); wherein each safety device (8) comprises: a supporting arm (9) pivotable about a substantially vertical axis (A1) and passing at one end thereof at the side of the at least one seat (7); and at least one blocking head (10) coupled to the supporting arm (9); wherein in a first configuration the supporting arm (9) is orthogonal to and above the at least one seat (7) and the at least one blocking head (10) is at the at least one seat (7) to hold the at least one supporting cable (2); in a second configuration the supporting arm (9) is parallel to and at the side of the at least one seat (7) so that the supporting arm (9) and the at least one blocking head (10) do not represent an obstacle to the transit of the at least one transport unit (3) along the shoe assembly (4).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102022000010649 filed on May 23, 2022 , the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The technical field of reference of the present invention refers to the sector of aerial cable transportation systems. Such specific technological application provides for the presence of at least one transport unit in which passengers and/or goods are transported. In these aerial cable systems, the transport units are moved in an aerial mode along a predefined route by at least one supporting cable. The driving of the units can be generated by a hauling cable or by a special motorization provided in each unit. Along the route, structures are present for supporting portions of the supporting cables known in the sector as "shoes". Such shoes are in particular present both in the end stations and along possible intermediate pylon structures. In such context, the present invention will deal with the problem of how to stably maintain the supporting cable in the corresponding shoe also in the presence of adverse weather events, such as for example strong lateral wind.

STATE OF THE ART

Aerial cable transportation systems are currently greatly widespread, and thus well known to a person skilled in the art operating in this particular technical field. In these systems, passengers and/or goods are transported along a route in special transport units, for example cabins, chairs or the like. The route is delimited at the opposite ends by two embarkation and disembarkation end stations, also known as upstream and downstream stations. In particular, according to the present invention, the term "aerial" refers to cable systems in which the transport units are moved along at least one supporting cable in a raised position with respect to the ground below (precisely aerial mode). The present invention refers to the aerial transportation systems with one or with two supporting cables per branch. Therefore, for the sake of simplicity in the continuation of the description, unless the contrary is explicitly stated, the words "supporting cable" will also refer to the case where the supporting cables are actually two. For the purposes of the present invention, the movement of the units can be generated by a hauling cable to which all the units are coupled or clamped, or by single motorizations present in the units, for example providing for motorized trolleys that slide on the supporting cables. As is known, the hauling cable, if present, is loop-sent between the end stations which are housed, for such purpose, on special pulleys (of which at least one is motorized) and runs along the entire route. On the contrary, the supporting cable is substantially fixed, i.e. is not moved between the stations except for periodic maintenance phases. As already mentioned in the foregoing, in an aerial cable transportation system of the type object of the present invention, each transport unit comprises at least one trolley with rollers which roll on the supporting cable.
An aerial cable transportation system as just described is very useful when the configuration of the ground below, or other contour factors, does not make the classic land drive practicable. For example, such aerial cable systems are used in the case where the route to be travelled provides for significant altimetric jumps, also with considerable slopes. Such route is typical of the zones of ski/mountain places and in such context these systems are also called ski lifts. However, the present invention and the aerial cable systems in general are also advantageously applied to urban contexts where the ground transportation is congested.
As is known, it is often necessary to also provide, along the route, for intermediate fixed structures between the end stations configured to support portions of the supporting cable. A reason for requiring such intermediate fixed structures can be the excessive distance between the end stations such not to enable arranging the cable in a single span. Another reason can be the altimetric profile of the path in the case where there are significant slope changes. Each intermediate fixed structure for supporting the cable usually comprises a vertical supporting structure, such as a pylon or a tower, on top of which devices for supporting the supporting cable are provided known as "shoes". In particular, the shoe comprises a substantially U-shaped seat open at the top for supporting the supporting cable. In systems with two supporting cables, the seats are obviously two and parallel to each other. Along the shoe, the hauling cable, if present, is instead supported by a series of rollers arranged below the seat of the supporting cable.
With regard to what just described, the portion of supporting cable housed in the seat of the shoe is less constrained because the trolley does not weigh on it and it is thus freer to move. Vertical or longitudinal displacements are absorbed by the system without any danger. On the contrary, a transversal displacement of the supporting cable is very dangerous because it can bring the cable to come out of the relative seat with consequent deviation of the cable from its theoretical line. There are adverse weather conditions, such as strong transversal wind and/or mantle of ice on the cables which, when detaching, can create a whiplash on the cable, whereby the supporting cable can thus come out of its seat and derail. Although for such purpose the shoes are laterally equipped with cable-catching devices, preventing such event is an object pursued by all manufacturers in order to increase the safety of the system.
A first solution currently known for such purpose provides for installing along the edges of the seat of the shoe fixed containment structures which effectively increase the volume of the seat for offering greater shelter from the wind. However, this solution is not optimal. Since the passage over the seat must in any case be free and without obstacles for enabling the transit of the carriages, such fixed structures necessarily have very reduced dimensions.
Based on the assumption that the problem of the supporting cable coming out of the seat occurs most frequently during the stop of the system, when in fact there are no circulating units which weigh on the cable anyway blocking it in some manner, there currently exists a second solution configured to act only during such stop phases of the system. This second solution provides for the presence of a movable arm pivotable about an axis parallel to the axial direction of the supporting cable, which, like a kind of level crossing, passes from a first position, in which it is substantially transversal to the cable in contact with the seat closing the open upper end thereof, to a second position in which it is substantially vertical and spaced apart from the seat.
Also this second solution, although preferable with respect to the first one because it does not obstruct the passage of the units during the operation of the system, has some drawbacks. In fact, especially in systems with two supporting cables, such arm must have a significant transversal length for closing both seats and such transversal length translates into a considerable weight to raise (and maintain raised) rotating about an axis parallel to that of the cables. From an engineering point of view, therefore, such solution has constructive drawbacks which do not recommend its use.
Finally, it is specified that everything described thus far with regard to the shoes present at the top of the pylons is also replicable at the disembarkation/embarkation stations where there are exactly similar shoe structures for supporting the supporting cables and where the same problems can thus occur. Furthermore, in the stations the free space above the seats in which to rotate the aforementioned arms about an axis parallel to that of the cables is often physically absent. Therefore, in many stations the second solution described is not installable.

DESCRIPTION OF THE INVENTION

Based on such prior art, an object of the present invention is to manufacture an innovative shoe assembly for supporting at least one supporting cable of an aerial cable transportation system, wherein the shoe assembly is capable of solving the problems of the prior art.
In particular, the object of the present invention is to provide a shoe assembly for supporting at least one supporting cable of an aerial cable transportation system, wherein the shoe assembly comprises an innovative safety device configured to hold the supporting cable, in particular inhibit the transversal movements thereof, at the relative seat during the stop phases of the system and which does not obstruct the passage of the trolleys during the operation of the system.
In view of such objects, a shoe assembly that can be improved by the present invention comprises:

an inlet;
an outlet;
at least one seat extending from the inlet to the outlet for supporting the at least one supporting cable;
at least one safety device for holding or supporting the at least one supporting cable at the corresponding at least one seat.

The above-mentioned elements are known per se to the person skilled in the art and no further details are required for their understanding. Just for the sake of clarity, it is noted that the terms "inlet" and "outlet" refer to the upstream and downstream portions of the shoe, i.e. the portions at which the transport units enter and exit the shoe. The seat supporting the supporting cable can per se have various different shapes. However, usually and preferably the seat is substantially U-shaped with more or less high side branches for making a groove which accommodates the supporting cable and which is open at the top. The above list mentions "at least one seat" because the present invention relates both to systems with one supporting cable as well as to systems with two supporting cables. In the latter case, the seats are two and are parallel to each other. Each seat obviously has a longitudinal development substantially coinciding with the axis of the corresponding supporting cable. The features of the safety device will be listed in the following. For the moment, it is emphasized that "at least one safety device" means that a shoe can have one or more safety devices. In case only one safety device is present, it is preferably located in the inlet zone of the shoe. If two safety devices are present, these are preferably arranged in the inlet zone and in the outlet zone of the shoe, respectively.
In such context, the main aspect of the present invention is to provide at least one innovative safety device for holding the at least one supporting cable, i.e. substantially inhibit the lateral or transversal movements thereof, at the corresponding at least one seat, wherein each safety device (one or more if present) comprises:

a supporting arm, preferably cylindrical, pivotable about a substantially vertical axis A1 (or orthogonal to the axis of the supporting cable) passing at one end thereof at the side of the at least one seat; and
at least one blocking head coupled to the arm and configured to block (in the sense of inhibiting at least the transversal movements) the at least one supporting cable housed in the corresponding seat.

Therefore, according to the present invention, the safety device comprises a movable arm (like a currently known prior art described in the foregoing) which, however, in an innovative manner, is not pivotable about an axis parallel to the seat or to the supporting cable but about an axis orthogonal to the seat or to the supporting cable. In this manner, the movement of the arm is no longer of the level crossing barrier type, but is of the door type in which the lifting of the arm is not provided. Since it is not necessary to lift and keep elements raised (elements which could also fall creating problems), no manoeuvring space for the arm above the seat is required.
Preferably, the supporting arm movable about the axis vertical to the supporting cable is cyclically and selectively switchable between two different configurations, in which:

in the first configuration, the supporting arm is orthogonal to the axis of the cable (or to the seat) and above the seat so that the at least one blocking head is located at the at least one seat for blocking (inhibiting at least the transversal movements) the at least one supporting cable; and
a second configuration in which the supporting arm is parallel to and at the side of the seat (rotation by 90° about the vertical axis) so that the at least one blocking head (and the arm) does not represent an obstacle to the transit of the transport units along the shoe assembly.

If the system comprises two supporting cables (and the shoe thus has two seats), in a corresponding manner each safety device comprises a supporting arm provided with two blocking heads which in the first configuration are located at the two seats.
If the arm supports only one blocking head, the latter is preferably movable along the corresponding supporting arm for reaching in an adjustable manner the corresponding seat and for compensating in an optimal manner transversal forces transmitted to the head by the cable (in case of transversal wind for example).
If the arm supports two blocking heads, the latter are preferably independently movable along the corresponding supporting arm for reaching in an adjustable manner the two seats and for compensating in an optimal manner the different transversal forces transmitted to the heads by the corresponding cables.
Preferably, the supporting arm is a cylindrical body so that the movement along the arm of the blocking head(s) is a motion along the axis of said arm.
Preferably, the blocking head (or heads) is pivotable about the axis of the corresponding (preferably cylindrical) supporting arm. This movement is useful because before rotating the arm it is thus possible to lift the heads from the seats so that in the subsequent rotation of the arm there is no danger of collision between heads and supporting cables.
Preferably, the blocking head (or heads) is substantially a U-shaped body so that in the first configuration it forms an inverted U-shaped seat above the seat of the cable capable of laterally blocking (holding) (inhibiting transversal movements) the supporting cable as well as superiorly restricting the displacement thereof to a maximum possible height. In fact, it is necessary to leave a vertical range of movement to the cable so that it adapts to the different vertical loads that can be present.
Preferably, the blocking head (or heads) comprises a pair of facing idle rollers which in the first configuration of the safety device are on opposite sides of the supporting cable with vertical axes (orthogonal to the axis of the cable) for enabling axial movements. An axial blocking of the cable would in fact be counterproductive and would generate stresses and forces in the system.
Preferably, each blocking head can be provided with portions which in the first configuration extend beyond the supporting cable and are in contact with (or face in proximity) the structure of the shoe below the seat. Such contact portions advantageously create the discharge points on the structure of possible transversal forces generated by the cable (for example, by effect of crosswind). In fact, in this case the cable acts on the rollers of the head and the latter discharges the strains onto the shoe only at the contact portions preventing the propagation of strains in all of the mechanism. Since each head is independently movable along the axis of the arm, such characteristic is independent for each head so as to discharge in a different manner different forces acting on the two supporting cables.
Preferably, the aforementioned contact portions can also be provided with heating devices for melting or preventing the formation of ice on the heads in the contact zone with the structure of the shoe.
Preferably, each blocking head comprises guiding portions configured to guide the supporting cable into the seat also if partially not aligned with the theoretical position. Such guiding portions are preferably lipped portions which in the first configuration are on opposite sides of the seat which extend axially (parallel to the axis of the cable) for a short section.
The present invention also extends to each aerial cable transportation system comprising at least one shoe assembly as described in the foregoing and claimed. In general, such a system comprises:

at least one transport unit;
at least one supporting cable for supporting the transport units;
a driving device for driving the transport unit(s) on the at least one supporting cable (for example a hauling cable or motorized carriages);
at least one fixed structure of the station type for passenger embarkation and disembarkation and/or of the pylon type.

In this context, the shoe assembly of the present invention can be provided in the fixed structure in the form both of a station and/or of pylons.
Finally, the present invention also refers to the method for operating the aforementioned aerial cable transportation system, wherein the method comprises the steps of:

a) providing such a system;
b) during the hours of operation of the system, switching the at least one safety device into the second configuration (arm parallel to the cable and at the side of the seats);
c) during the stop of the system, switching the at least one safety device into the first configuration (orthogonal arm above the seats).

LIST OF THE FIGURES

Further features and advantages of the present invention will become apparent from the following description of a non-limiting example embodiment thereof, with reference to the figures of the accompanying drawings, wherein:

Figure 1 schematically shows a portion of an aerial cable transportation system that can be improved with the present invention;
Figure 2 shows the enlargement of the portion indicated by reference numeral II in Figure 1;
Figure 3 shows a portion of the system of Figure 2 in which a safety device is provided according to an embodiment of the present invention;

Figures 4-6 show the safety device of Figure 3 in different configurations of use;
Figure 7 shows an enlargement of the safety device in the configuration of Figure 3;
Figures 8-10 show different views and details of the safety device of Figure 3.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the attached figures, Figure 1 schematically discloses a portion of an aerial cable transportation system indicated as a whole by reference numeral 1 and which can be improved thanks to the present invention. In such non-limiting example, the aerial cable system 1 comprises cables (indicated in Figure 1 in general by reference numeral 2) and a passenger embarkation and disembarkation station 14 is visible. This example comprises two parallel branches characterizing an ascending branch and a descending branch of the system. The arrows A and B in Figure 1 indicate precisely the driving directions of the ascending and descending branches. Figure 1 illustrates one of the many transport units 3 present in the system, which are arranged one after the other along both the ascending and descending branches. In the illustration of Figure 1, a first transport unit 3 is at the station 14 inside which the transport units 3 are usually disengaged from the cables 2. The second transport unit 3 shown in Figure 1 is travelling on the ascending branch and is arranged between the station 14 and a first intermediate supporting fixed structure 15 in the form of a pylon 16. The function of the pylons 16 arranged between the stations is to divide the cables into distinct spans. Already in Figure 1 it is possible to note that the transport unit 3 of the shown example comprises a cabin 17 at the bottom and a supporting arm 18 (or suspension arm) at the top which connects it to the cable 2. Reference numeral 19 in Figure 1 schematically shows the device that connects the supporting arm 18 to the cable 2, in Figure 2 it will be described in greater detail in the form of a trolley. In Figure 1, it is finally possible to note that a shoe assembly 4 for supporting the cable 2 is present at the top of the pylon 16. Although Figure 1 shows a system with several transport units, the present invention also extends to systems with a single transport unit and/or systems in which the cabin or cabins travel in both directions on the same branch of the system.
Figure 2 shows the enlargement of the portion indicated by reference numeral II in Figure 1. In this figure, it is visible how the system 1 comprises two supporting cables 2 and one hauling cable 13. However, for the purposes of the present invention, the system can also comprise only one supporting cable, and the hauling cable can also be replaced by similar means adapted to control the driving of the transport unit. Figure 2 shows how the arm 18 is connected to the supporting cables 2 by means of a carriage 19 provided with rollers 20 for rolling on the supporting cables 2. Reference numeral 25 indicates the vice for the selective vicing to the pulling cable 13. The shoe 4 is only partly visible in Figure 2 (in Figure 1, the inlet portion 5 and the outlet portion 6 are visible very schematically). As is visible in Figure 2, along the shoe 4, the supporting cables 2 are housed at suitable U-shaped seats on the upper end of the shoe 4 while the hauling cable 13 is housed along a series of rollers 21 placed at a lower height. Therefore locally, the cable 2 can perform axial, vertical and transversal movements in which the latter are to be restricted for safety reasons and for preventing the cable 2 from coming out of the seat.
Figure 3 shows a portion of the system of Figure 2 in which a safety device is visible according to an embodiment of the present invention, i.e. an innovative device configured to hold (when required) the supporting cable in the seat of the shoe. In this example, the seats (indicated by reference numeral 7) are two and parallel for housing the two supporting cables 2. The development of the seats 7 or the axis of the supporting cables 2 defines a longitudinal direction. Reference numeral 8 in Figure 3 indicates an example of an innovative safety device according to the present invention. As is visible in this figure, the safety device 8 comprises a substantially cylindrical arm 9 having an axis A2 which supports two blocking heads 10. In the configuration shown in Figure 3, the arm is arranged orthogonal to and above the seats 7 and the heads 10 are at the seats 7 for holding the cables 2 in the seats 7. Such configuration is the one which is imposed on the device 8 during the downtime phases of the system 1. In the phases of use of the system, the passage over the seats must obviously be free so as not to create obstacles to the transit of the transport units.
Figures 4-6 show subsequent steps in which the safety device of figure 3 is in different configurations for passing from the position of Figure 3 to a position in which it frees the seats. In Figure 4 it is visible that the first controlled movement is the rotation by 90° of the heads 10 about the axis A2 of the arm 9 so that the heads 10 no longer act on the cables 2. In Figure 5 it is visible that the second controlled movement is the rotation of the arm 9 about the vertical axis A1 at one end thereof placed at the side of the seats 7. In Figure 6 it is visible that the last controlled movement is the rotation by 90° (in a direction opposite to that of Figure 4) of the heads 10 about the axis A2 of the arm. The final outcome of these three rotations brings the arm 8 and the heads 10 to be arranged at the side of the seats 7 parallel to the cables 2 so as to reduce to the minimum the required bulk and so as not to obstruct the passage of the carriages. Reference numeral 22 in these figures indicates the motorization that controls these rotations.
Figure 7 shows an enlargement of the safety device in the configuration of Figure 3 and allows appreciating how the heads 10 are made. Each head comprises a base coupled to the arm 9 and a free end shaped so that in the first configuration it forms an inverted U-shaped seat over the seat 7 of the shoe 4. Reference numeral 23 indicates a stop for blocking the rotation of the heads 10 in the correct position and reference numeral 11 indicates idle rollers which in such configuration have vertical axes for allowing axial movements of the cable 2.
Figure 8, and the enlarged detail of Figure 9, show a front view of the assembly and allows seeing how the heads 10 do not allow the transversal coming out of the cables 2. The arrows F1 and F2 in Figure 8 indicate that each head 10 is independently movable along the arm 9 (along the axis A2) while reference numeral 12 in Figure 9 schematizes portions of the heads close to or at the structure of the shoe which are heating devices (for example of the electric resistance type) suitable for preventing the formation of ice on the heads 10 in the contact zone with the structure of the shoe 4. These elements 12, which can also not be of heated type, also act as discharge points for discharging the transversal forces coming from the supporting cable 2 onto the shoe 4, thus preventing the forces from passing through the entire mechanism. In fact, in case of transversal forces, the supporting cable 2 acts against the rollers 11 of the heads 10, which discharges these strains onto the shoe 4 only at the contact elements 12. Such capability is offered by both heads in an independent manner since they are independently movable in the direction of the axis A2 of the arm (a movement which also enables absorbing geometric tolerances).
Finally, Figure 10 allows seeing the presence of lipped portions 24 which protrude from the heads 10. In the first configuration, such portions 24 have an axial development parallel to the cable 2 and act as guiding elements for directing the cable 2 into the heads 10.
It is evident that modifications and variations can be made to the invention described herein with respect to the example shown in the figures. In fact, the main aspect of the present invention lies in the innovative safety device with movable arm as claimed.

Claims

A shoe assembly for an aerial cable transportation system (1) comprising at least one supporting cable (2) and at least one transport unit (3) moved on the supporting cable (2); wherein the shoe assembly (4) comprises:
- an inlet (5);

- an outlet (6);

- at least one seat (7) extending from the inlet (5) to the outlet (6) to support the at least one supporting cable (2);

- at least one safety device (8) to hold the at least one supporting cable (2) at the corresponding at least one seat (7);
characterized in that
each safety device (8) comprises:
- a supporting arm (9) pivotable about a substantially vertical axis (A1) and passing at one end thereof at the side of the at least one seat (7); and

- at least one blocking head (10) coupled to the supporting arm (9); in which

- in a first configuration, the supporting arm (9) is orthogonal to and above the at least one seat (7) and the at least one blocking head (10) is at the at least one seat (7) to hold the at least one supporting cable (2);

- in a second configuration the supporting arm (9) is parallel to and at the side of the at least one seat (7) so that the supporting arm (9) and the at least one blocking head (10) do not represent an obstacle to the transit of the at least one transport unit (3) along the shoe assembly (4).
Shoe assembly as claimed in claim 1, wherein the shoe assembly (4) comprises a first and second safety device (8) at the inlet (5) and outlet (6), respectively.
Shoe assembly as claimed in a claim 1 or 2, wherein the at least one blocking head (10) is movable along the corresponding supporting arm (9).
Shoe assembly as claimed in any one of the preceding claims, wherein the at least one blocking head (10) is pivotable about the axis of the corresponding supporting arm (9).
Shoe assembly as claimed in any one of the preceding claims, wherein the at least one blocking head (10) is substantially U-shaped such that at the at least one seat (7) in the first configuration it laterally blocks the at least one supporting cable (2) and superiorly restricts its movement to a maximum possible excursion.
Shoe assembly as claimed in claim 5, wherein the at least one blocking head (10) comprises a pair of facing rollers (11) which in the first configuration are on opposite sides of the at least one supporting cable (2) to allow axial movements.
Shoe assembly as claimed in any one of the preceding claims, wherein the at least one blocking head (10) comprises contact or facing portions (12) proximate to a structure of the shoe assembly (4) inferior to the seat such that lateral forces transmitted by the cable (2) to the head (10) are discharged to the shoe assembly (4) only at the contact portions (12).
Shoe assembly as claimed in claim 7, wherein contact portions (12) comprise heating devices.
Shoe assembly as claimed in any one of the preceding claims, wherein the at least one blocking head (10) comprises guiding portions (24) for the at least one supporting cable (2) that in the first configuration are on opposite sides of the at least one supporting cable (2) and extend axially.
Shoe assembly as claimed in any one of the preceding claims, wherein the shoe assembly (4) comprises two parallel seats (7) to support two supporting cables (2) of an aerial cable transportation system comprising two supporting cables; the supporting arm (9) supporting two blocking heads (10) configured to block both supporting cables (2) in the seats (7).
Shoe assembly as claimed in claim 10, wherein the two blocking heads (10) are independently movable along the supporting arm (9).
Aerial cable transportation system; wherein the system (1) comprises:
- at least one transport unit (3);

- at least one supporting cable (2) to support the transport units (3);

- a driving device (13) for driving the transport units (3) on the at least one supporting cable (2);

- at least one station (14) for passenger embarkation and disembarkation; and/or

- at least one structure (15) outside at least one station (14) ;
characterized in that
the at least one station (14) and/or the at least one structure (15) comprise a shoe assembly (4) as claimed in any one of the preceding claims.
Method for operating an aerial cable transportation system for transporting passengers, the method comprising the steps of:
a) providing a system (1) as claimed in claim 11;

b) during the hours of operation of the system (1) switching the at least one safety device (4) to the second configuration;

c) during the stop of the system (1) switching the at least one safety device (4) to the first configuration.