Emergency bearing mechanism

1. A bearing unit of a pulley of a cable car wherein the pulley is mounted on a shaft, the bearing unit comprising:

bearings to be mounted in a bearing frame and supporting the shaft, said bearings including at least one first bearing and at least one second bearing;

said first bearing having an inner ring and an outer ring, said inner ring being connected to the shaft; and

said second bearing having an inner ring and an outer ring, said outer ring of said first bearing is connected to said inner ring of said second bearing and is mounted in the bearing frame via said second bearing, said inner ring and said outer ring of said second bearing which is configured for emergency operation being connected fixedly to one another so as to rotate together, a connection between said inner ring and said outer ring of said second bearing having a predetermined break point;

at least one supporting device; and

said second bearing being disposed radially outside said first bearing and optionally offset axially with respect to said first bearing, and in that, in a case of a defect of said first bearing, said inner ring of said second bearing or an intermediate ring connecting said first bearing to said second bearing being supported on the shaft via said at least one supporting device.

2. The bearing unit according to claim 1 , wherein said first bearing is a bearing which is configured for normal operation and said second bearing is a bearing which is configured for emergency operation.

3. The bearing unit according to claim 2 , wherein said inner ring and said outer ring of said second bearing which is configured for emergency operation are connected fixedly to the bearing frame so as to rotate with the bearing frame.

4. The bearing unit according to claim 3 , wherein said inner ring of said second bearing which is configured for emergency operation is connected via a predetermined break point fixedly to the bearing frame so as to rotate with the bearing frame.

5. The bearing unit according to claim 1 , wherein the predetermined break point is formed by at least one fastener selected from the group consisting of screws and shear pins.

6. The bearing unit according to claim 5 , wherein said fastener connects said supporting device and said outer ring of said second bearing to one another.

7. The bearing unit according to claim 5 ,

further comprising a centering bearing cap connected to the bearing frame; and

wherein said fastener connects said supporting device and said centering bearing cap to one another.

8. The bearing unit according to claim 7 , further comprising elastic bushes mounted in said supporting device, said fastener is mounted in said elastic bushes.

9. The bearing unit according to claim 1 , further comprising emergency running bearings, a hub of the pulley is mounted in the bearing frame via said emergency running bearings.

10. The bearing unit according to claim 9 , wherein said emergency running bearings each have an inner ring disposed with play on the hub.

11. The bearing unit according to claim 1 , wherein said first bearing, said second bearing and/or said emergency running bearings are plain bearings or anti-friction bearings.

12. A bearing unit of a pulley of a cable car wherein the pulley is mounted on a shaft, the bearing unit comprising:

bearings to be mounted in a bearing frame and supporting the shaft, said bearings including at least one first bearing and at least one second bearing;

said first bearing having an inner ring and an outer ring, said inner ring being connected to the shaft; and

said second bearing having an inner ring and an outer ring, said outer ring of said first bearing is connected to said inner ring of said second bearing and is mounted in the bearing frame via said second bearing;

at least one supporting device; and

said second bearing being disposed radially outside said first bearing and optionally offset axially with respect to said first bearing, and in that, in a case of a defect of said first bearing, said inner ring of said second bearing or an intermediate ring connecting said first bearing to said second bearing being supported on the shaft via said at least one supporting device.

13. The bearing unit according to claim 12 , wherein said supporting device is a bearing cap.

14. A drive configuration of a cable car, the drive configuration comprising:

a shaft;

a pulley mounted on said shaft;

a bearing frame; and

bearing units, each of said bearing units containing:

bearings mounted in said bearing frame and supporting said shaft, said bearings including at least one first bearing and at least one second bearing;

said first bearing having an inner ring and an outer ring, said inner ring being connected to the shaft; and

said second bearing having an inner ring and an outer ring, said outer ring of said first bearing is connected to said inner ring of said second bearing and is mounted in the bearing frame via said second bearing, said inner ring and said outer ring of said second bearing which is configured for emergency operation being connected fixedly to one another so as to rotate together, a connection between said inner ring and said outer ring of said second bearing having a predetermined break point;

at least one supporting device; and

said second bearing being disposed radially outside said first bearing and optionally offset axially with respect to said first bearing, and in that, in a case of a defect of said first bearing, said inner ring of said second bearing or an intermediate ring connecting said first bearing to said second bearing being supported on the shaft via said at least one supporting device.

15. The bearing unit according to claim 14 ,

further comprising emergency running bearings; and

wherein said pulley has a hub mounted in said bearing frame via said emergency running bearings.

16. The bearing unit according to claim 14 , wherein said emergency running bearings each have an inner ring disposed with play on said hub.