Bathtub lift

1. A bathtub lift, comprising:

a floor plate,

a seat plate adjustable to vary the distance between the seat plate and the floor plate,

a back plate detachably arranged on the seat plate,

a driven adjustment device, and

a locking device for releasing the back plate,

wherein the back plate supports the driven adjustment device for adjusting a distance between the floor plate and the seat plate with a drive,

wherein the back plate is movable relative to the seat plate,

wherein the locking device is arranged in a different location than a surface of the seat plate facing away from the floor plate, and

wherein the back plate is only detachable while the seat plate is in an end position closest to the floor plate.

2. The bathtub lift according to claim 1 , wherein the locking device comprises at least two positively locking components configured to be positively locked and released via the adjustment device.

3. The bathtub lift according to claim 2 , wherein one of the positively locking components is a locking bolt arranged at the seat plate, and another one of the positively locking components is a passage opening arranged at the back plate for the locking bolt to be inserted, wherein the adjustment device varies a relative position of the at least two positively locking components to each other.

4. The bathtub lift according to claim 3 , wherein the locking bolt is formed linearly movable parallel to the surface of the seat plate against a force.

5. The bathtub lift according to claim 1 , wherein the seat plate and the back plate each have a respective curved sliding surface with a corresponding radius, wherein the sliding surface of the seat plate is longer than the sliding surface of the back plate.

6. The bathtub lift according to claim 1 , wherein the seat plate comprises at least one stop for the back plate.

7. The bathtub lift according to claim 3 , wherein the passage opening is arranged in an arm of the back plate.

8. The bathtub lift according to claim 7 , wherein the arm comprises an upward sliding surface for actuating the locking bolt.

9. The bathtub lift according to claim 1 , wherein the adjustment device comprises a pair of position-variable racks.

10. The bathtub lift according to claim 9 , wherein the position-variable racks are supported on the floor plate in a guided manner.

11. The bathtub lift according to claim 10 , wherein the back plate is adjustable relative to the seat plate at different angles between 90° and 150°.

12. A bathtub lift comprising:

a floor plate,

a seat plate having an adjustable distance to the floor plate,

a back plate detachably arranged on the seat plate,

a scissor system with scissor arms between the floor plate and the seat plate, and

a driven adjustment device

wherein the back plate supports the driven adjustment device for adjusting the distance between the floor plate and the seat plate,

wherein the adjustment device comprises an electromotive drive with exactly one electric motor,

wherein the adjustment device further comprises at least two position-variable racks,

wherein a transmission operatively arranged between the drive and the at least two position-variable racks includes a plurality of toothed gears as gear drives and is configured to simultaneously drive the at least two position-variable racks synchronously

wherein the scissor arms are movably guided in guides arranged on at least one of the floor plate and the seat plate, wherein the scissor arms include at least one pair of parallel scissor arms with identically orientated ends horizontally spaced apart from each other and connected to each other via a rotatably mounted shaft,

wherein the guides are toothed racks and the shaft has toothed gears meshing with the toothed racks, and

wherein the ends of the scissor arms are supported by the floor plate and are movably mounted on the floor plate while the toothed gears of the shaft are supported by the scissor arms and engage the toothed racks, but do not rest on the toothed racks.

13. The bathtub lift according to claim 12 , wherein the at least two position-variable racks are arranged parallel to one another and equidistant to lateral edges of the back plate.

14. The bathtub lift according to claim 12 , wherein the position-variable racks are supported on the floor plate.

15. The bathtub lift according to claim 14 , wherein the floor plate has a region, that supports the position-variable racks in a guided manner, wherein the region is a recess, a groove, a stop or an indentation.

16. A bathtub lift, comprising:

a floor plate,

a seat plate having an adjustable distance to the floor plate,

a back plate detachably arranged on the seat plate,

a scissor system with scissor arms between the floor plate and the seat plate, and

a driven adjustment device,

wherein the back plate supports the driven adjustment device for adjusting the distance between the floor plate and the seat plate,

wherein the adjustment device comprises an electromotive drive with exactly one electric motor,

wherein the adjustment device further comprises at least two position-variable racks,

wherein a transmission operatively arranged between the drive and the at least two position-variable racks includes a plurality of toothed gears as gear drives and is configured to simultaneously drive the at least two position-variable racks synchronously

wherein the scissor arms are movably guided in guides arranged on at least one of the floor plate and the seat plate, wherein the scissor arms include at least one pair of parallel scissor arms with identically orientated ends horizontally spaced apart from each other and connected to each other via a rotatably mounted shaft,

wherein the guides are toothed racks and the shaft has toothed gears meshing with the toothed racks, and

further comprising a respective scroll wheel for each of the toothed gears, wherein the respective scroll wheel is connected to the shaft in a torque-proof manner, wherein the respective scroll wheel is configured to roll directly on the floor plate or in a guide groove in the floor plate.