Door locking handle assembly

A bilateral-type door locking handle assembly comprising:

• a front casing (2) fixedly mounted on a front side of a door (1);
• a rear casing (3) fixedly mounted on a rear side of said door (1);
• a front handle (6) having its base shaft portion (5) rotatably mounted in a bearing portion (4) of said front casing (2);
• a rear handle (9) having its base shaft portion (8) rotatably mounted in a bearing portion (7) of said rear casing (3);
• a base plate (10) which is received in said rear casing (3) and fixedly mounted on said door (1);
• a driving sleeve (12) which is rotatably mounted in a bearing portion (16) of said base plate (10), provided with an axial receiving groove (19) in its side wall portion and provided with an interlocking projection (29) in its rear-end portion;
• a thumb turn (15) having its base-end shaft portion (14) mounted rotatably in a bearing portion (13) of said rear casing (3);
• a lock casing (17) which is connected with said base-end shaft portion (14) of said thumb turn (15) so as to be rotatably driven together with said thumb turn (15), is disposed between said rear casing (3) and said base plate (10), provided with a pair of diametrically opposed locking blades (18), (48) in its outer surface, and provided with a receiving hole (49) in its front side;
• a locking core (20) which is received in said receiving hole (49) of said lock casing (17) behind said interlocking projection (29) of said driving sleeve (12), provided with a locking hole (50) in its front surface, having a locking pin (51) projected from an inner surface of said locking hole (50), and provided with a locking projection (53) in a central portion of an inner bottom surface of said locking hole (50), said locking hole (50) assuming a regular hexagonal shape in cross-section, provided that one of its six corners of said regular hexagonal shape is formed into a curved surface (50a);
• wherein said assembly is adapted for use with a spring (21) disposed between said rear casing (3) and a rectangular trunk surface (52) of said lock casing (17) so as to hold said thumb turn (15) in its locking and unlocking position;
• a left-side latch plate (25) which has its intermediate portion rotatably mounted on a fixed pivot (22) of said rear casing (3), its upper-end hook portion (23) projected from a left-side opening (24) of said rear casing (3), and has a locking projection (30) formed in its upper-end shoulder portion, said locking projection (30) abutting against said locking blade (18);
• a right-side latch plate (28) which has its intermediate portion rotatably mounted on a fixed pivot (54) of said rear casing (3), its upper-end hook portion (26) projected from a left-side opening (27) of said rear casing (3), and a locking projection (31) formed in its upper-end shoulder portion, said locking projection (31) abutting against said locking blade (48);
• a spring (32) disposed between said rear casing (3) and said left-side latch plate (25) so as to bias said left-side latch plate (25) into its locking position;
• a spring (55) disposed between said rear casing (3) and said right-side latch plate (28) so as to bias said right-side latch plate (28) into its locking position;
• an interlocking shaft (35) which is rotatably mounted between said rear casing (3) and said base plate (10), and provided with an axial hole (34) in which an axial shaft (33) of said rear handle (9) is inserted, said axial shaft (33) being inserted also into an axial hole (36) of said front handle (6);
• a driving plate (40) which is provided in said interlocking shaft (35), and provided with a driving projection (39) formed integrally with its upper-end portion, said driving projection (39) abutting against each of a follower arm portion (37) of said left-side latch plate (25) and a follower arm portion (38) of said right-side latch plate (28);
• a key (60) which is provided with a key rod (42) inserted into a key hole (41) of said front casing (2), has a front-end portion (56) of said key rod (42) formed into a predetermined shape corresponding in cross-section to that of said locking hole (50) of said locking core (20) so as to have said front-end portion (56) fitted in said locking hole (50), is provided with an axially-extending locking groove (57) in a side surface of said front-end portion (56) so as to receive said locking projection (53) of said locking core (20) in said locking groove (57), is provided with a locking concave portion (58) in a central portion of its end surface so as to receive said locking projection (53) of said locking core (20) in said locking concave portion (58), and, is provided with a locking pin (59) in a side surface of said key rod (42), said locking pin (59) being inserted into said receiving groove (19) of said driving sleeve (12), said predetermined shape of said front-end portion (56) of said key rod (42) being a regular hexagonal shape, provided that one of its six corners of said regular hexagonal shape is formed into a curved surface (56a);
• a socket piece (45) provided in a left-side post wall (44) of a doorway (43) so as to be engaged with and disengaged from said front-end hook portion (23) of said left-side latch plate (25);
• and
• a socket piece (47) provided in a right-side post wall (46) of said doorway (43) so as to be engaged with and disengaged from said front-end hook portion (26) of said right-side latch plate (28).