Small-size Multi-axis Ankle Prosthesis

A small-size multi-axis ankle prosthesis, comprising a lower part (A), a joint axis (B), an upper part (C), a first spring (1), a second spring (2), a third spring (3) and a fourth spring (4),

• wherein the lower part (A) comprises a base plate (5), a first ball cover group (6), a first ball rod group (7), a first spring seat group (8) and a first arc plate assembly (9);
• the base plate (5) is disc-shaped, and an outer periphery of the base plate is uniformly provided with four flanges of a first flange group (10);
• the first arc plate assembly (9) comprises a first arc plate (15) and a transverse plate (14), and the first arc plate (15) is fixed on an upper surface of the transverse plate (14);
• two arc holes of a second arc hole pair (e) are provided on the first arc plate (15) adjacent to a front end thereof;
• two arc holes of a third arc hole pair (f) are provided on the first arc plate (15) adjacent to a rear end thereof;
• the joint axis (B) comprises a subtalar joint axis (16), a left connecting block (17a), a right connecting block (17b), an ankle axis (18), a front connecting block (19a), a rear connecting block (19b), a bolt (20), and an oil-free bushing group (21);
• wherein the left connecting block (17a) comprises a first cylindrical cap (24a) and a first perforated block (25a) which is fixed at a center portion on a front end of the first cylindrical cap (24a);
• the right connecting block (17b) comprises a second cylindrical cap (24b) and a second perforated block (25b) which is fixed at a center portion on a rear end of the second cylindrical cap (24b);
• the front connecting block (19a) comprises a third cylindrical cap (28a) and a third perforated block (29a) which is fixed at a center portion on a left end of the third cylindrical cap (28a);
• the rear connecting block (19b) comprises a fourth cylindrical cap (28b) and a fourth perforated block (29b) which is fixed at a center portion on a right end of the fourth cylindrical cap (28b);
• the upper part (C) comprises a second arc plate assembly (30), a second spring seat group (31), a second ball rod group (32), a second ball cover group (33) and a top plate (34), the top plate (34) is disc-shaped and an outer periphery of the top plate is uniformly provided with four flanges of a second flange group (37);
• the second arc plate assembly (30) comprises a second arc plate (35) and a transverse plate (36);
• the second arc plate (35) is fixedly connected to a bottom of the transverse plate (36), a fifth arc hole pair (g) is provided on the second arc plate (35) adjacent to a left lower end thereof, and a sixth arc hole pair (h) is provided on the second arc plate (35) adjacent to a right lower end thereof;
• the four flanges of the second flange group (37) of the top plate (34) in the upper part (C) are symmetrical with the four flanges of the first flange group (10) of the base plate (5) in the lower part (A) in an up-down direction;
• upper ends of the first spring (1), the second spring (2), the third spring (3) and the fourth spring (4) are respectively fixed with four spring seats of the second spring seat group (31) in the upper part (C);
• lower ends of the first spring (1), the second spring (2), the third spring (3) and the fourth spring (4) are respectively fixedly connected with four spring seats of the first spring seat group (8) in the lower part (A);
• the joint axis (B) is located in a space surrounded by the lower part (A), the first spring (1), the second spring (2), the third spring (3), the fourth spring (4) and the upper part (C);
• the third perforated block (29a) of the front connecting block (19a) in the joint axis (B) is connected with the fifth arc hole pair (g) of the second arc plate (35) in the upper part (C) through a bolt;
• the fourth perforated block (29b) of the rear connecting block (19b) in the joint axis (B) is connected with the sixth arc hole pair (h) of the second arc plate (35) in the upper part (C) through a bolt;
• the first perforated block (25a) of the left connecting block (17a) in the joint axis (B) is connected with the second arc hole pair (e) of the first arc plate (15) in the lower part (A) through a bolt;
• the second perforated block (25b) of the right connecting block (17b) in the joint axis (B) is connected with the third arc hole pair (f) of the first arc plate (15) in the lower part (A) through a bolt.