TECHNICAL FIELD

The present invention relates to a cable transportation system with at least one haul cable.

More specifically, the present invention relates to a cable transportation system comprising a supporting structure defining an axis of rotation; a pulley extending about the axis of rotation, and having a groove designed to be engaged by the haul pulley; and a bearing assembly connected to the pulley and the supporting structure to allow the pulley to rotate about the axis of rotation with respect to the supporting structure .

BACKGROUND ART

The bearing assembly requires constant maintenance for the pulley to rotate smoothly, and lubrication to prevent the bearing assembly from seizing. Even with thorough care and maintenance, however, the bearing assembly may accidentally seize, thus resulting in stoppage of the entire cable transportation system. Particularly when used for passenger transport, stoppage of the system calls for emergency rescue procedures to disembark the passengers, which in some cases is extremely slow, painstaking work requiring the use of special equipment. DISCLOSURE OF INVENTION

It is an object of the present invention to provide a cable transportation system designed to eliminate the drawbacks of known systems.

Another object of the present invention is to provide a cable transportation system designed to enable easy, low-cost passenger rescue.

According to the present invention, there is provided a cable transportation system with at least one haul cable, the cable transportation system comprising a supporting structure with a tubular portion defining an axis of rotation; a pulley extending about the axis of rotation; and a bearing assembly, which is connected to the pulley and the supporting structure to allow the pulley to rotate about the axis of rotation with respect to the supporting structure, and comprises at least a first and at least a second bearing arranged concentrically and in series, so as to ensure rotation of the pulley about the axis of rotation and with respect to the supporting structure by means of at least the first or second bearing.

A first bearing may thus be used for normal operation of the system, and a second bearing for operating the system in emergency passenger rescue situations .

In a preferred embodiment of the cable transportation system, the bearing assembly comprises a sleeve located between the first and second bearing, and fixable selectively to the supporting structure and the pulley.

The pulley can thus be selected to rotate about the tubular portion of the supporting structure by means of the first or second bearing. To select which of the first and second bearings is to be used, the sleeve is fixable selectively to the pulley or the supporting structure .

Fixing the sleeve to the supporting structure by means of at least one dynamometer pin is particularly advantageous, by enabling constant monitoring of the first bearing, preferably used for normal operation of the cable transportation system. Moreover, the dynamometer pin is designed to break when subjected to a load exceeding a given break load.

In a preferred embodiment, the sleeve is fixable to the pulley by means of at least one lock pin, by which to simply lock the damaged bearing quickly and easily in an emergency situation, and so prevent the damage to the bearing from getting any worse.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which : Figure 1 shows a schematic, partly sectioned side view, with parts removed for clarity, of a cable transportation system in accordance with the present invention;

Figure 2 shows a larger-scale section, with parts removed for clarity, of a detail of the Figure 1 cable transportation system in a first operating configuration;

Figure 3 shows a larger-scale section, with parts removed for clarity, of a detail of the Figure 1 cable transportation system in a second operating configuration;

Figure 4 shows a larger-scale section, with parts removed for clarity, of a variation of Figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Number 1 in Figure 1 indicates as a whole a cable transportation system comprising a haul cable 2.

In the example described, specific reference is made to a cable transportation system with one haul and support cable 2; it being understood, however, that the present invention also applies to transportation systems with more than one cable.

Cable transportation system 1 and haul cable 2 extend between two arrival/departure stations 3, only one of which is shown in the drawings. Arrival/departure station 3 comprises a supporting structure 4; a pulley 5, which rotates about an axis A with respect to supporting structure 4; and an electric drive member 6 connected to the pulley by a transmission 7. Supporting structure 4 comprises a frame, in turn comprising a beam 8, and a tubular portion 9 (Figure 2) integral with beam 8. Because drive member 6 is located over beam 8, and pulley 5 is located beneath beam 8, transmission 7 extends at least partly through tubular portion 9 (Figure 2) and, in the example shown, comprises a reduction gear 10 over beam 8; a shaft 11 (Figure 2) housed for rotation inside tubular portion 9 (Figure 2) ; and a joint 12 fitted to shaft 11 (Figure 2) and pulley 5.

In a variation not shown, drive member 6 and/or reduction gear 10 are/is located beneath beam 8.

Pulley 5 comprises an outer-edge groove 13 for housing haul cable 2, and is connected to supporting structure 4 to rotate about axis A by means of a bearing assembly 14 (Figure 2) .

In other words, as shown in Figure 2, shaft 11 transmitting rotation to pulley 5 extends along and rotates about axis A; tubular portion 9 extends concentrically with and about shaft 11; pulley 5 extends and rotates about axis A; and bearing assembly 14 is located between the inner edge of pulley 5 and the tubular portion 9 of supporting structure 4. In the example shown, pulley 5 comprises an inner-edge sleeve 15 for mounting bearing assembly 14. Bearing assembly 14 comprises a sleeve 16 designed to selectively connect integrally to pulley 5 or supporting structure 4 - in the example shown, to beam 8; two bearings 17; and a bearing 18. The two bearings 17 are located side by side and concentrically between pulley 5 and sleeve 16, and bearing 18 extends from sleeve 16 to tubular portion 9 of supporting structure 4. In other words, each bearing 17 is a rolling bearing mounted between pulley 5 and sleeve 16, and bearing 18 is a sliding bearing mounted between sleeve 16 and tubular portion 9. Though specific reference is made in this description to two bearings 17, this is in no way limiting : the number of bearings 17 depends on the characteristics of the forces exchanged, and of the cable transportation system, and is purely a design issue. Likewise, though specific reference is made in this description to one sliding bearing, this is in no way limiting, the number of sliding bearings being selected according to the characteristics of the cable transportation system.

Sleeve 15 is fitted along the inner edge of pulley 5, and has a shoulder 19 for assembling bearings 17. Sleeve 16 has a shoulder 20 for assembling bearings 17, is fitted loosely about tubular portion 9, has a shoulder 21 engaging a shoulder 22 of tubular portion 9, and is locked axially by an annular flange 23 integral with tubular portion 9. And bearing 18 comprises sliding elements 24, normally made of Teflon or similar.

In the example shown, the two rolling bearings 17 are separated by a spacer 25.

Rolling bearings 17 and sliding bearing 18 are arranged concentrically - in the example shown, with sliding bearing 18 inwards of rolling bearings 17 - and permit rotation of pulley 5 about supporting structure 4 - in the example shown, about axis A. In other words, the two rolling bearings 17 are arranged "parallel", and sliding bearing 18 is located "in series" with rolling bearings 17. In actual use, sliding bearing 18 is used as an emergency bearing, and is normally locked. More specifically, sleeve 16 is connected integrally to supporting structure 4 by means of at least one dynamometer pin 26. The example shown employs two dynamometer pins 26 (only one shown in Figures 2 and 3) , each of which engages two holes 27 and 28 parallel to axis A and formed respectively in beam 8 and in the thickness of sleeve 16, comprises two sensors (not shown) for detecting the stress exerted on it, and is designed to break when the load exerted on it exceeds a given break load.

In an emergency situation (breakdown of bearings 17), sleeve 16 can be connected integrally to pulley 5 as shown more clearly in Figure 3. With reference to Figure 3, sleeve 15 is integral with a ring 29 having one face facing and very close to sleeve 16. Ring 29 has at least one radial hole 30, and sleeve 16 has at least one dead radial hole 31 at the same height as and selectively alignable with hole 30. In the example shown, ring 29 and sleeve 16 have two holes 30 and two holes 31 respectively; and each pair of holes 30 and 31 is selectively alignable and engageable by a pin 32 for integrally connecting pulley 5 and sleeve 16 and so locking rolling bearings 17.

With reference to Figures 2 and 3, joint 12 is defined by a number of assembled parts for connecting shaft 11 to pulley 5, and also forms a hermetic seal between shaft 11 and pulley 5, to permit oil-bath lubrication of bearings 17 and 18.

In actual use, during normal operation of cable transportation system 1, sliding bearing 18 is maintained in the locked position shown in Figure 2. Conversely, when rolling bearings 17 show signs of malfunctioning, they are locked by inserting pins 30, and dynamometer pins 26 are removed to permit operation of sliding bearing 18, as shown in Figure 3.

Cable transportation system 1 can thus be kept running to rescue the passengers, without causing any further damage to rolling bearings 17. Dynamometer pins 26 also provide for constantly monitoring the efficiency, and so preventing critical operation, of rolling bearings 17.

In the Figure 4 variation, a connecting pin 33 underneath pulley 5 is substituted for connecting pin 32, and fits inside two aligned holes 34 and 35 formed in joint 12, integral with pulley 5, and in sleeve 16 respectively .

In the example shown, connecting pin 33 and hole 34 define two opposite shoulders, between which is located a spring 36 for preventing accidental insertion of connecting pin 33 inside hole 35.

Due to its location, dynamometer pin 26 is not visible in Figure 4.

The Figure 4 variation operates in the same way as described above, but has the advantage of enabling easier access to pin 33 and therefore faster intervention in the event of a malfunction of bearings 17.

The present invention obviously also applies to embodiments not covered in the above detailed description, and to equivalent embodiments within the protective scope of the accompanying Claims.