Footrest driving apparatus and lift chair therewith

1. A footrest driving apparatus used in a lift chair, comprising:

a seat frame ( 2 ), having two mounting boards ( 21 ) disposed at two lateral sides thereof, wherein the two mounting boards ( 21 ) are fixed to each other, and each of the two mounting boards ( 21 ) has a curved guide slot ( 22 ) formed thereon;

a footrest member ( 4 ), disposed at a front side of the seat frame ( 2 ) and configured to move between a stowed position and a reclined position relative to the seat frame ( 2 );

a driving mechanism ( 3 ), comprising a driving bar ( 31 ), and two driving arms ( 32 ) disposed at two lateral sides of the driving bar ( 31 ) and one-to-one corresponding to the two mounting boards ( 21 ), wherein each of the driving arms ( 32 ) has a guide rod ( 33 ) and a pin ( 34 ), the guide rod ( 33 ) matches with the curved guide slot ( 22 ) of a corresponding one of the two mounting boards ( 21 ), and the pin ( 34 ) is rotatably connected with the corresponding one of the two mounting boards ( 21 ); and

a footrest linkage mechanism ( 5 ), connected to the seat frame ( 2 ), the driving mechanism ( 3 ) and the footrest member ( 4 );

wherein the driving bar ( 31 ) is configured to drive the guide rod ( 33 ) of each of the two driving arms ( 32 ) to correspondingly move between a first position and a second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ); and

wherein when the guide rod ( 33 ) of each of the two driving arms ( 32 ) moves to the first position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ), the driving mechanism ( 3 ) drives the footrest linkage mechanism ( 5 ) to move the footrest member ( 4 ) to the stowed position, and when the guide rod ( 33 ) of each of the two driving arms ( 32 ) moves to the second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting hoards ( 21 ), the driving mechanism ( 3 ) drives the footrest linkage mechanism ( 5 ) to move the footrest member ( 4 ) to the reclined position.

2. The footrest driving apparatus according to claim 1 , wherein the footrest linkage mechanism ( 5 ) comprises:

a first linkage member ( 51 ) fixed to the two driving arms ( 32 ), wherein the first linkage member ( 51 ) has a first end fixed to the guide rods ( 33 ) of the two driving arms ( 32 ), a second end, and a middle portion located therebetween and fixed to the pins ( 34 ) of the two driving arms ( 32 );

a second linkage member ( 52 ) having a first end rotatably connected to the second end of the first linkage member ( 51 ), a second end, and a middle portion located therebetween;

a third linkage member ( 53 ) having a first end rotatably connected to the second end of the second linkage member ( 52 ), and a second end rotatably connected to the seat frame ( 2 ); and a fourth linkage member ( 54 ) having a first end rotatably connected to the footrest member ( 4 ), and a second end rotatably connected to the middle portion of the second linkage member ( 52 ).

3. The footrest driving apparatus according to claim 1 , wherein the seat frame ( 2 ) further comprises a first reinforcing member ( 23 ) disposed between the two mounting boards ( 21 ) to connect and fix the two mounting boards ( 21 ).

4. The footrest driving apparatus according to claim 3 , wherein the lift chair has a base frame ( 1 ) having two linkage seats ( 7 ) disposed at two lateral sides thereof and one-to-one corresponding to the two mounting boards ( 21 ), each of the two linkage seats ( 7 ) is connected to a corresponding one of the two mounting boards ( 21 ) by two linkage members, allowing the seat frame ( 2 ) to move vertically between an upper position and a bottom position relative to the base frame ( 1 ) through rotation of the two linkage members.

5. The footrest driving apparatus according to claim 4 , wherein the seat frame ( 2 ) further comprises a second reinforcing member ( 24 ) located behind and in parallel to the first reinforcing member ( 23 ), and when the seat frame ( 2 ) is located at the bottom position, the second reinforcing member ( 24 ) is in contact with the two linkage seats ( 7 ).

6. The footrest driving apparatus according to claim 1 , wherein the footrest member ( 4 ) has a footrest extension member ( 81 ) located at a front side thereof to support ankles of a user.

7. A lift chair, comprising:

a base frame ( 1 ) having two linkage seats ( 7 ) disposed at two lateral sides thereof; and

a footrest driving apparatus, comprising:

a seat frame ( 2 ), disposed above the base frame ( 1 ), having two mounting boards ( 21 ) disposed at two lateral sides thereof and one-to-one corresponding to the two linkage seats ( 7 ), wherein the seat frame ( 2 ) is configured to move vertically between an upper position and a bottom position relative to the base frame ( 1 ), the two mounting boards ( 21 ) are fixed to each other, and each of the two mounting boards ( 21 ) has a curved guide slot ( 22 ) formed thereon;

a footrest member ( 4 ), disposed at a front side of the seat frame ( 2 ) and configured to move between a stowed position and a reclined position relative to the seat frame ( 2 );

a driving mechanism ( 3 ), comprising a driving bar ( 31 ), and two driving arms ( 32 ) disposed at two lateral sides of the driving bar ( 31 ) and one-to-one corresponding to the two mounting boards ( 21 ), wherein each of the driving arms ( 32 ) has a guide rod ( 33 ) and a pin ( 34 ), the guide rod ( 33 ) matches with the curved guide slot ( 22 ) of a corresponding one of the two mounting boards ( 21 ), and the pin ( 34 ) is rotatably connected with the corresponding one of the two mounting boards ( 21 ); and

a footrest linkage mechanism ( 5 ), connected to the seat frame ( 2 ), the driving mechanism ( 3 ) and the footrest member ( 4 );

wherein the driving bar ( 31 ) is configured to drive the guide rod ( 33 ) of each of the two driving arms ( 32 ) to correspondingly move between a first position and a second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ); and

wherein when the guide rod ( 33 ) of each of the two driving arms ( 32 ) moves to the first position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ), the driving mechanism ( 3 ) drives the footrest linkage mechanism ( 5 ) to move the footrest member ( 4 ) to the stowed position, and when the guide rod ( 33 ) of each of the two driving arms ( 32 ) moves to the second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ), the driving mechanism ( 3 ) drives the footrest linkage mechanism ( 5 ) to move the footrest member ( 4 ) to the reclined position.

8. The lift chair according to claim 7 , wherein the footrest linkage mechanism ( 5 ) comprises:

a first linkage member ( 51 ) fixed to the two driving arms ( 32 ), wherein the first linkage member ( 51 ) has a first end fixed to the guide rods ( 33 ) of the two driving arms ( 32 ), a second end, and a middle portion located therebetween and fixed to the pins ( 34 ) of the two driving arms ( 32 );

a second linkage member ( 52 ) having a first end rotatably connected to the second end of the first linkage member ( 51 ), a second end, and a middle portion located therebetween;

a third linkage member ( 53 ) having a first end rotatably connected to the second end of the second linkage member ( 52 ), and a second end rotatably connected to the seat frame ( 2 ); and

a fourth linkage member ( 54 ) having a first end rotatably connected to the footrest member ( 4 ), and a second end rotatably connected to the middle portion of the second linkage member ( 52 ).

9. The lift chair according to claim 7 , wherein the seat frame ( 2 ) further comprises a first reinforcing member ( 23 ) disposed between the two mounting boards ( 21 ) to connect and fix the two mounting boards ( 21 ).

10. The lift chair according to claim 9 , wherein each of the two linkage seats ( 7 ) is connected to a corresponding one of the two mounting boards ( 21 ) by two linkage members, allowing the seat frame ( 2 ) to move vertically between the upper position and the bottom position relative to the base frame ( 1 ) through rotation of the two linkage members.

11. The lift chair according to claim 9 , wherein the seat frame ( 2 ) further comprises a second reinforcing member ( 24 ) located behind and in parallel to the first reinforcing member ( 23 ), and when the seat frame ( 2 ) is located at the bottom position, the second reinforcing member ( 24 ) is in contact with the two linkage seats ( 7 ).

12. The lift chair according to claim 7 , further comprising a backrest member ( 8 ), disposed at a back side of the seat frame ( 2 ) and configured to move between a backrest stowed position and a backrest reclined position relative to the seat frame ( 2 ).

13. The lift chair according to claim 12 , being switchable between a first stance, a second stance, a third stance and a fourth stance, wherein:

in the first stance, the seat frame ( 2 ) is in the bottom position, the footrest member ( 4 ) is in the stowed position, the backrest member ( 8 ) is in the backrest stowed position, and the guide rod ( 33 ) of each of the two driving arms ( 32 ) is in the first position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 );

in the second stance, the seat frame ( 2 ) is in the upper position, the footrest member ( 4 ) is in the stowed position, the backrest member ( 8 ) is in the backrest stowed position, and the guide rod ( 33 ) of each of the two driving arms ( 32 ) is in the first position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 );

in the third stance, the seat frame ( 2 ) is in the bottom position, the footrest member ( 4 ) is in the reclined position, the backrest member ( 8 ) is in the backrest stowed position, and the guide rod ( 33 ) of each of the two driving arms ( 32 ) is in the second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ); and

in the fourth stance, the seat frame ( 2 ) is in the bottom position, the footrest member ( 4 ) is in the reclined position, the backrest member ( 8 ) is in the backrest reclined position, and the guide rod ( 33 ) of each of the two driving arms ( 32 ) is in the second position in the curved guide slot ( 22 ) of the corresponding one of the two mounting boards ( 21 ).

14. The lift chair according to claim 7 , wherein the footrest member ( 4 ) has a footrest extension member ( 81 ) located at a front side thereof to support ankles of a user.