Structurally improved manual sofa stretching device
A structurally improved manual sofa stretching device includes a base. A functional frame is arranged on the base. The functional frame includes a leg structure, a seat structure and a back structure. The leg structure is connected to the seat structure, and the seat structure is connected to the back structure. The seat structure includes a mounting side plate, and the mounting side plate is arranged on the base. The leg structure includes a third foot rod, a fourth foot rod, a first extension link rod, a second extension link rod, a third extension link rod, a fourth extension link rod, a first Z-shaped linkage rod, a second Z-shaped linkage rod, a first footrest, a second footrest and a small footrest.
1. A structurally improved manual sofa stretching device, comprising
a base;
wherein a functional frame is arranged on the base;
the functional frame comprises a leg structure, a seat structure and a back structure;
the leg structure is connected to the seat structure, and the seat structure is connected to the back structure;
the seat structure comprises a mounting side plate, and the mounting side plate is arranged on the base;
the leg structure comprises a third foot rod, a fourth foot rod, a first extension link rod, a second extension link rod, a third extension link rod, a fourth extension link rod, a first Z-shaped linkage rod, a second Z-shaped linkage rod, a first footrest, a second footrest and a small footrest;
a first end of the first extension link rod is rotatably connected to a middle of the second footrest;
a second end of the first extension link rod is rotatably connected to a first end of the fourth foot rod;
a second end of the fourth foot rod is rotatably connected to a first end of the mounting side plate;
a first end of the second extension link rod is rotatably connected to a second end of the first footrest;
a second end of the second extension link rod is rotatably connected to a first end of the third foot rod;
a second end of the third foot rod is rotatably connected to the first end of the mounting side plate;
a first end of the third extension link rod is rotatably connected to a second end of the fourth extension link rod;
a second end of the third extension link rod is rotatably connected to a middle of the first extension link rod;
a first end of the fourth extension link rod is rotatably connected to a middle of the first footrest;
a first end of the first footrest is provided with a first mounting hole;
a first end of the first Z-shaped linkage rod is rotatably connected to one a first end of the second footrest;
a second end of the first Z-shaped linkage rod is rotatably connected to a middle of the third extension link rod;
a second end of the second footrest is provided with a second mounting hole;
a first end of the second Z-shaped linkage rod is rotatably connected to the middle of the third extension link rod;
a second end of the second Z-shaped linkage rod is rotatably connected to a first end of the small footrest;
a middle of the small footrest is rotatably connected to a middle of the second extension link rod;
a second end of the small footrest is provided with a third mounting hole;
the middle of the second extension link rod is further provided with a protruding limit part, and the protruding limit part abuts against a middle of the second Z-shaped linkage rod;
the back structure comprises a backrest member;
the backrest member is rotatably connected to a second end of the mounting side plate;
a limit assembly is arranged on the base, and
the limit assembly is configured to limit a position of the backrest member.
2. The structurally improved manual sofa stretching device according to claim 1 , wherein
the seat structure further comprises a front support member, a rear support member, a front linkage member, an intermediate linkage member, a rear linkage member, a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod;
a first end of the first connecting rod is rotatably connected to the backrest member;
a second end of the first connecting rod is rotatably connected to a first end of the intermediate linkage member;
a second end of the intermediate linkage member is rotatably connected to a first end of the rear support member;
a second end of the rear support member is rotatably connected to a second end of the base;
a middle of the intermediate linkage member is rotatably connected to a first end of the third connecting rod;
a second end of the third connecting rod is rotatably connected to a middle of the front linkage member;
a first end of the front linkage member is rotatably connected to a first end of the front support member;
a second end of the front support member is rotatably connected to a first end of the base;
a second end of the front linkage member is rotatably connected to a middle of the mounting side plate;
a middle of the rear linkage member is rotatably connected to the middle of the mounting side plate;
a first end of the rear linkage member is rotatably connected to a first end of the second connecting rod;
a second end of the second connecting rod is rotatably connected to a middle of the front support member;
a second end of the rear linkage member is rotatably connected to a first end of the fourth connecting rod; and
a second end of the fourth connecting rod is rotatably connected to a middle of the fourth foot rod.
3. The structurally improved manual sofa stretching device according to claim 1 , wherein
the limit assembly comprises a limit bushing;
the second end of the mounting side plate is provided with a guide slot;
the limit bushing is connected to the backrest member through a rotating shaft, and
the limit bushing abuts against a side of the guide slot.
4. The structurally improved manual sofa stretching device according to claim 2 , wherein
the front linkage member is crescent-shaped, and the middle of the front linkage member is provided with a riveting hole and a spare hole.
5. The structurally improved manual sofa stretching device according to claim 2 , wherein
a first spring is further connected between the third connecting rod and the base through a first mounting assembly, and the first spring is configured to assist in unfolding the leg structure;
the first mounting assembly comprises a first spring peg and a second spring peg;
a middle of the third connecting rod is provided with a first positioning hole;
the first end of the base is provided with a second positioning hole;
a first end of the first spring peg is inserted into the first positioning hole, and a second end of the first spring peg is connected to a first end of the first spring; and
a first end of the second spring peg is inserted into the second positioning hole, and a second end of the second spring peg is connected to a second end of the first spring.
6. The structurally improved manual sofa stretching device according to claim 2 , wherein
a second spring is further connected between the intermediate linkage member and the base through a second mounting assembly, and the second spring is configured to assist in retracting the back structure;
the second mounting assembly comprises a third spring peg;
the first end of the intermediate linkage member is provided with a third positioning hole;
the middle of the mounting side plate is provided with a fourth positioning hole, and the fourth positioning hole is strip-shaped;
a first end of the third spring peg is inserted into the third positioning hole;
a second end of the third spring peg is connected to a first end of the second spring; and
a second end of the second spring is hooked in the fourth positioning hole.
7. The structurally improved manual sofa stretching device according to claim 3 , wherein
an end of the guide slot is provided with an arc-shaped transition portion.
8. The structurally improved manual sofa stretching device according to claim 3 , wherein
the limit bushing is made of metal.
9. The structurally improved manual sofa stretching device according to claim 3 , wherein
the limit bushing is made of stainless steel.