Friction drive lift

1. A stair lift for transporting a load, comprising:

a longitudinal guide comprising a longitudinal length having a first end and a second opposed end defining a longitudinal axis therein between and further comprising opposed first and second side surfaces, the first opposed side surface comprising a first side running surface and the second opposed side surface comprising a second side running surface; and

a carriage which is transportable along the guide comprising:

a first roller comprising a first roller peripheral friction surface which is in frictional engagement with the first side running surface for guiding the carriage along the guide; and

a second roller comprising a second roller peripheral friction surface which is in frictional engagement with the second side running surface for guiding the carriage along the guide,

wherein the first roller peripheral friction surface of the first roller comprises a plurality of first roller members that peripherally extend in a plane perpendicular to a rotational axis of the first roller and the first side running surface of the first opposed side surface of the guide comprises a plurality of longitudinal first side running surface members that longitudinally extend along the longitudinal axis of the longitudinal guide and that fit complementary and make contact with the plurality of the first roller members for supporting the plurality of the first roller members of the first roller on the plurality of the longitudinal first side running surface members of the first side running surface to carry at least part of the weight of the load,

wherein, each of the first roller members is a first roller flange and each of the first side running surface members is a first side running surface recess which receives one of the first roller flanges, or each of the first roller members is a first roller groove and each of the first side running surface members is a first side running surface ridge which is received by one of the first roller grooves,

wherein each of the first roller members comprises an upper member side surface and a lower member side surface, which both are in contact with one of the first side running surface members, and

wherein the carriage comprises a first drive that is in a driveable connection with the first roller to rotate the first roller about the rotational axis of the first roller to drive the first roller along the first side running surface of the longitudinal guide such that the carriage is transportable along the guide by means of friction between the plurality of the first roller members of the first roller peripheral friction surface and the plurality of the longitudinal first side running surface members of the first side running surface.

2. A stair lift for transporting a load, comprising:

a longitudinal guide comprising a longitudinal length having a first end and a second opposed end defining a longitudinal axis therein between and further comprising opposed first and second side surfaces, the first opposed side surface comprising a first side running surface and the second opposed side surface comprising a second side running surface; and

a carriage which is transportable along the guide comprising:

a first roller comprising a first roller peripheral friction surface which is in frictional engagement with the first side running surface for guiding the carriage along the guide; and

a second roller comprising a second roller peripheral friction surface which is in frictional engagement with the second side running surface for guiding the carriage along the guide,

wherein the first roller peripheral friction surface of the first roller comprises a plurality of first roller members that peripherally extend in a plane perpendicular to a rotational axis of the first roller and the first side running surface of the first opposed side surface of the guide comprises a plurality of longitudinal first side running surface members that longitudinally extend along the longitudinal axis of the longitudinal guide and that fit complementary and make contact with the plurality of the first roller members for supporting the plurality of the first roller members of the first roller on the plurality of the longitudinal first side running surface members of the first side running surface to carry at least part of the weight of the load,

wherein each of the first roller members comprises an upper member side surface and a lower member side surface, which both are in contact with one of the first side running surface members, and

wherein the carriage comprises a first drive that is in a driveable connection with the first roller to rotate the first roller about the rotational axis of the first roller to drive the first roller along the first side running surface of the longitudinal guide such that the carriage is transportable along the guide by means of friction between the plurality of the first roller members of the first roller peripheral friction surface and the plurality of the longitudinal first side running surface members of the first side running surface.

3. The stair lift according to claim 2 , wherein the stair lift further comprises a load carrier, wherein a centre of gravity of the load carrier lies outwards from the second side running surface and thus at a distance from the guide and away from the first side running surface when seen in a direction perpendicular to the second side surface, and wherein the first roller member and the complementary first side running surface member are arranged higher than the second roller and the second side running surface.

4. The stair lift according to claim 2 , wherein the second roller friction surface is provided with a second roller member which peripherally extends in a plane perpendicular to a rotational axis of the second roller and the second side running surface of the guide is provided with a longitudinal second side running surface member which fits complementary with the second roller member for supporting the second roller member of the second roller on the second side running surface member of the second side running surface to carry at least part of the weight of the load.

5. The stair lift according to claim 4 ,

wherein the plurality of longitudinal first side running surface members comprise at least three first side running surface members;

wherein the longitudinal second side running surface member comprises at least three second side running surface members;

wherein the first roller comprises at least three first roller members; and

wherein the second roller comprises at least three second roller members.

6. The stair lift according to claim 2 , wherein the carriage is provided with a second drive that is in a driveable connection with the second roller such that the carriage is transportable along the rail by means of friction between the second roller member of the second roller and the second roller member of the second side running surface.

7. The stair lift according to claim 2 , wherein the carriage is provided with a third roller, wherein the third roller comprises a third roller peripheral friction surface which is in frictional engagement with the second side running surface for guiding the carriage along the guide.

8. The stair lift according to claim 7 , wherein the first roller is arranged between the second roller and the third roller, when seen in a direction along the guide.

9. The stair lift according to claim 7 , wherein the carriage is provided with a fourth roller, and wherein the fourth roller comprises a fourth roller peripheral friction surface which is in frictional engagement with the first side running surface for guiding the carriage along the guide.

10. The stair lift according to claim 7 , wherein the stair lift further comprises a load carrier, wherein a centre of gravity of the load carrier lies outwards from the second side running surface and thus at a distance from the guide and away from the first side running surface when seen in a direction perpendicular to the second side surface and wherein the first roller is arranged opposite to the third roller or the second roller.

11. The stair lift according to claim 2 , wherein the carriage is free from active pressure means configured to increase the friction between the first roller and the first side running surface via a spring.

12. The stair lift according to claim 2 , wherein the first roller member is a first roller flange and the first side running surface member is a first side running surface recess which receives the first roller flange.

13. The stair lift according to claim 12 , wherein the first roller flange has a point shape outer end and the first side running surface recess has a complementary V-shape inner end.

14. The stair lift according to claim 2 , wherein the first roller member is a first roller groove and the first side running surface member is a first side running surface ridge which is received by the first roller groove.

15. The stair lift according to claim 14 , wherein the first roller groove has a point shape inner end and the first side running surface ridge has a complementary V-shape outer end.

16. The stair lift according to claim 2 , wherein the first roller member comprises an upper member side surface and a lower member side surface, and wherein an upper member side surface angle defined between the upper member side surface and an auxiliary plane perpendicular to the rotational axis of the first roller is larger than a lower member side surface angle defined between the lower member side surface and the auxiliary plane.

17. The stair lift according to claim 2 , wherein the guide comprises a topside and a downside and the carriage is free from rollers engaging on the topside and the downside.

18. The stair lift according to claim 2 , wherein the guide is an aluminium extruded rail.

19. The stair lift according to claim 2 ,

wherein the plurality of longitudinal first side running surface members comprise at least three first side running surface members; and

wherein the plurality of first roller members comprises at least three first roller members.

20. A method for transporting a load over a staircase by means of a stair lift, comprising:

providing the stair lift according claim 2 ; and

transporting the carriage along the guide from a start point to an end point.