Rotatable seat for preventing falling backwards

1. A rotatable seat for preventing falling backwards comprising:

a seat member having a saddle-shaped surface that is used for allowing users to sit thereon and including a pommel portion, a seat portion and a cantle portion arranged in turn from front to back, and

a spherical surface portion projecting from a bottom surface of the saddle-shaped surface;

a base member disposed under the seat member and having at least one support portion on a top surface thereof; and

a safety member for preventing users from falling backwards including at least one first magnet and at least one second magnet that are attracted to each other;

wherein the spherical surface portion of the seat member is moveably disposed on the support portion of the base member so that the seat member is able to be moved in different directions or at different angles relative to the base member; wherein the first magnet is set on a front part of the spherical surface portion of the seat member, close to the pommel portion while the second magnet is mounted in the support portion of the base member; wherein users can work out by keeping their bodies balanced or shaking their buttocks, like horseback riding while sitting on the saddle-shaped surface of the seat member; wherein the pommel portion of the seat member is inclined forwards, attached to and positioned on the support portion of the base member, unable to be moved freely due to attraction between the first magnet and the second magnet of the safety member for preventing users from falling backwards when the rotatable seat is not in use; the users' buttocks can cross over the pommel portion easily to sit on the seat member more safely while using the rotatable seat.

2. The device as claimed in claim 1 , wherein the spherical surface portion of the seat member is a hemisphere.

3. The device as claimed in claim 1 , wherein the support portion on the top surface of the base member is a flat surface.

4. The device as claimed in claim 3 , wherein the second magnet is arranged at a center of the flat surface.

5. The device as claimed in claim 1 , wherein the support portion of the base member includes three spherical bumps that are projecting from the top surface of the base member, having the same height and arranged at the top surface in a regular triangle manner; thus the spherical surface portion of the seat member is moveably supported by the three spherical bumps.

6. The device as claimed in claim 5 , wherein a bottom surface of the pommel portion of the seat member is leaning against one of the spherical bumps.

7. The device as claimed in claim 6 , wherein the second magnet is mounted in the spherical bump being leaned against by the bottom surface of the pommel portion.

8. The device as claimed in claim 1 , wherein the rotatable seat further includes a stopping member for preventing falling backwards; the stopping member for preventing falling backwards is mounted between a bottom surface of the cantle portion of the seat member and the top surface of the base member to stop and prevent the cantle portion from being inclined continuously after being moved to a certain angle.

9. The device as claimed in claim 8 , wherein the stopping member for preventing falling backwards further includes at least one projecting part with a certain height; the projecting part is arranged at a rear part of the spherical surface portion of the seat member, close to the cantle portion, the bottom surface of the cantle portion of the seat member, or a rear part of the top surface of the base member.