Retractable massage roller

1. A retractable massage roller comprising: two end caps and a plurality of ring-shaped unit bodies arranged along an axial direction, the two end caps being respectively connected to outermost two unit bodies of the plurality of unit bodies;

wherein every three adjacent unit bodies of the plurality of unit bodies are connected through a plurality of connecting rods, the plurality of connecting rods are independent of the three adjacent unit bodies, each of the plurality of connecting rods is movably disposed on and passes through the three adjacent unit bodies and thereby the three adjacent unit bodies are capable of sliding on each of the plurality of connecting rods;

wherein outermost two unit bodies of the three adjacent unit bodies are respectively positionally-limited at two ends of each of the plurality of connecting rods through first limiting mechanisms, in a situation of the retractable massage roller being in a stretched state; and

wherein every two adjacent unit bodies of the plurality of unit bodies are positionally-limited through second limiting mechanisms, in a situation of the retractable massage roller being in a contracted state;

wherein each of the first limiting mechanisms comprises a rigid limiter and a flexible limiter;

wherein each of the second limiting mechanisms is a metal elastic sheet or an elastic hook.

2. The retractable massage roller according to claim 1 , wherein the first limiting mechanisms are respectively disposed on the two ends of each of the plurality of connecting rods, the rigid limiter is located at an outer side of each of the plurality of connecting rods, and the flexible limiter is located at an inner side of each of the plurality of connecting rods; and the first limiting mechanisms are capable of being engaged with the outermost two unit bodies of the three adjacent unit bodies to achieve position limiting, under a cooperative action of the rigid limiter and the flexible limiter.

3. The retractable massage roller according to claim 2 , wherein the rigid limiter is integrally formed on each of the plurality of connecting rods or fixed on each of the plurality of connecting rods through a fastener, and is further configured for preventing the outermost two unit bodies of the three adjacent unit bodies from separating from each of the plurality of connecting rods.

4. The retractable massage roller according to claim 2 , wherein the flexible limiter is a damping member integrally formed on each of the plurality of connecting rods or fixed on each of the plurality of connecting rods, the damping member is configured for creating a damping effect onto one of the outermost two unit bodies in a situation of the unit body sliding on the connecting rod, and the one of the outermost two unit bodies is capable of sliding back and forth on the damping member under an action of an external force, wherein the damping member comprises an elastic hook, a metal elastic sheet or a rubber member.

5. The retractable massage roller according to claim 1 , wherein each of the plurality of unit bodies is provided with the second limiting mechanisms-, and each of the second limiting mechanisms is capable of realizing position limiting by means of clamping, bonding or sucking.

6. The retractable massage roller according to claim 1 , wherein an outer circumference of each of the plurality of unit bodies is provided with a plurality of soft massage portions.

7. The retractable massage roller according to claim 1 , wherein a middle portion of each of the plurality of connecting rods is provided with a convex portion-, and the unit body located in a middle of the three adjacent unit bodies is tightened through the convex portion in the situation of the retractable massage roller is in the stretched state.