Muscle relaxant device with increased pressure resistance

Abstract

A muscle relaxant device comprises a main body unit (3) and an air inflation unit (4). The main body unit (3) has an axis (X), a predetermined length (L) along the axis (X), and a predetermined width (D) perpendicular to the axis (X). The main body unit (3) includes an inflatable element (32) defining an inflation chamber (31) and a structural reinforcement layer (33) covering an outer surface of the inflatable element (32) and made of a different material than the inflatable element (32). The inflatable element (32) is variable between an inflated state, in which the air pressure in the inflation chamber (31) is between 2 psi and 35 psi, and a deflated state, in which the air pressure in the inflation chamber (31) is less than 2 psi. The air inflation unit (4) is connected to the main body unit (3) to direct air into and out of the inflation chamber (31).

Description

[0001] The present disclosure relates to a muscle relaxation device, in particular to a muscle relaxation device with increased compressive strength.

[0002] With reference to Fig. 1, a commercially available foam roller 1 is typically formed using a single layer of material 11 to create multiple massage areas 111 for contact with a user's body. This allows various massage effects to be achieved by pressing or rolling the foam roller 1 on the user's body.

[0003] However, since the foam roller 1 is composed of a single layer of material 11, the massage effect produced when the foam roller 1 touches the user's body is monotonous and cannot be changed, so that the use of the foam roller 1 cannot meet the massage needs of different users or different body parts thereof.

[0004] Since the foam roller 1 is cylindrical, has a considerable volume and cannot be folded, it can take up a lot of space when stored.

[0005] Therefore, an object of the present invention is to provide a muscle relaxation device that can produce different pressure effects on the muscles of different body parts of a user, has good pressure resistance, and can be folded to reduce the occupied space, thereby improving space efficiency, portability, and safety in use. Another object of the present invention is to provide a muscle relaxation device that can overcome at least one of the disadvantages of the prior art.

[0006] These objects are achieved by the invention through the features of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] According to one aspect of the invention, the muscle relaxation device comprises a main body unit and an air inflation unit. The main body unit has an axis, a predetermined length along the axis, and a predetermined width perpendicular to the axis. The main body unit includes an inflatable member defining an inflation space, and a structural reinforcement layer covering an outer surface of the inflatable member and made of a different material from a material of the inflatable member. The inflatable member is variable between an inflated state, in which the air pressure in the inflation space is between 2 psi and 35 psi, and a deflated state, in which the air pressure in the inflation space is less than 2 psi. The air inflation unit is connected to the main body unit to direct air into and out of the inflation space.

[0008] According to another aspect of this disclosure, the muscle relaxation device comprises a main body unit and an air inflation unit. The main body unit is cylindrical with an axis and has a predetermined length along the axis and a predetermined width perpendicular to the axis. The main body unit includes an inflatable member made of rubber or synthetic rubber that defines an inflation space, a structural reinforcement layer covering an outer surface of the inflatable member and made of a material different from a material of the inflatable member, and a contact layer covering an outer surface of the structural reinforcement layer. The inflatable member is variable between an inflated state in which the air pressure in the inflation space is between 2 psi and 35 psi, and a deflated state in which the air pressure in the inflation space is less than 2 psi.The air inflation unit is connected to the main body unit to direct air into and out of the inflation chamber.

[0009] Further features and advantages of the invention will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings. It should be noted that various features may not be drawn to scale. Fig. 1 is a perspective view of a conventional foam roller. Fig. 2 is a fragmentary sectional view of a muscle relaxation device according to the first embodiment of the present disclosure with an inflatable member thereof in an inflated state. Fig. 3 is an enlarged fragmentary sectional view of a portion of Fig. 2, with one air inflation unit removed for clarity. Fig. 4 is a sectional view along the line IV-IV of Fig. 2. Fig. 5 is an enlarged fragmentary sectional view of a portion of Fig. 2, which shows an inflation needle inserted into an elastic valve body of an inflation valve of the air inflation unit of the first embodiment to bring the elastic valve body into an open state. Fig. 6 is a similar view to Fig. 2, but with the inflatable element in a deflated state. Fig. 7 is a partially cutaway perspective view of the muscle relaxant device of the first embodiment, showing an outer surface of a structural reinforcement layer covered with a contact layer. Fig. 8 is a fragmentary sectional view of a muscle relaxation device according to the second embodiment of the present disclosure with an inflatable member in an inflated state. Fig. 9 is an enlarged fragmentary sectional view of a portion of Fig. 8, which shows an inflator and a valve assembly of an air inflation unit of the second embodiment. Fig. 10 is a similar view to Fig. 8, but with the inflatable element in a deflated state. Fig. 11 is a fragmentary sectional view of a muscle relaxation device according to the third embodiment of the present disclosure. Fig. 12 is an enlarged fragmentary sectional view of a portion of Fig. 11, which shows a handle part of an inflator of an air inflation unit of the third embodiment engaged with a socket. Fig. 13 is a view similar to Fig. 12, but with the handle part of the inflator detached from the socket for inflating air. Fig. 14 is a view similar to Fig. 12, but with an air cylinder remote from an outer threaded portion of a carrier for venting air.

[0010] Before describing the invention in detail, it should be noted that, where deemed appropriate, reference numerals or suffixes of reference numerals have been repeated in the figures to indicate corresponding or analogous elements which may optionally have similar characteristics.

[0011] According to the Fig. 2 to 4, a muscle relaxation device according to the first embodiment of the present disclosure includes a main body unit 3 and an air inflation unit 4.

[0012] The main body unit 3 is cylindrical with an axis (X) extending in a longitudinal direction, and has a predetermined length (L) along the axis (X) and a predetermined width (D) perpendicular to the axis (X). The predetermined length (L) ranges from 5 inches to 50 inches, preferably 36 inches. The predetermined width (D) ranges from 2 inches to 15 inches, preferably 6 inches. The main body unit 3 includes an inflatable member 32 defining an inflation space 31 and having two ends 321 opposite each other along the axis (X), a structural reinforcement layer 33 covering an outer surface of the inflatable member 32, and a mounting seat 34 disposed at and connected to one of the ends 321 of the inflatable member 32.

[0013] The inflatable member 32 is made of rubber or synthetic rubber and is manufactured using a rubber or synthetic rubber sheet and a mold. The rubber or synthetic rubber sheet is first folded multiple times and then pressed and molded directly in the mold. By the above-mentioned method, the inflatable member 32 is formed with two annular projections 322 extending from an inner surface thereof, respectively near the ends 321 thereof, and surrounding the axis (X). Since the method for manufacturing the inflatable member 32 is known in the art and does not constitute a technical feature of the present invention, details are omitted here. Furthermore, the annular projections 322 may be formed at various positions due to differences in compression molding methods and should not be limited to the disclosed embodiment.

[0014] The inflatable element 32 is adjustable between an inflated state (see Fig. 2 and Fig. 4) and an empty state (see Fig. 6) Variable. When inflated, the air pressure in the inflation chamber 31 is between 2 psi and 35 psi, preferably 10 psi. When deflated, the air pressure in the inflation chamber 31 is less than 2 psi.

[0015] The structural reinforcement layer 33 can be made of at least one of the following materials: yarn, woven fabric, PVC mesh, mesh fabric (made by a weaving or textile process), chemical fabric, and nylon. In this embodiment, the structural reinforcement layer 33 is formed by winding a yarn around the outer surface of the inflatable member 32 until it completely covers the outer surface of the inflatable member 32. This can increase the compressive strength of the inflatable member 32, so that the overall appearance of the inflatable member 32 can be maintained and the inflatable member 32 is not easily damaged when the inflatable member 32 is pressed and the air pressure inside is high. The structural reinforcement layer 33 has two ends 331 opposite each other along the axis (X) and is provided with a through hole 330 in one of the ends 331.

[0016] It should be noted that the yarn is not limited to being wrapped around the outer surface of the inflatable member 32. In other variations of this embodiment, the yarn may be interwoven in a braided manner around the outer surface of the inflatable member 32. It is worth noting that when the material of the structural reinforcing layer 33 is a woven fabric, a PVC mesh, or a mesh fabric, the material is bonded to the outer surface of the inflatable member 32 in an adhesive manner; or the material consisting of a yarn wrapped around and bonded to a composite material of the PVC mesh is bonded to the outer surface of the inflatable member 32. Since the above method is known in the art, a detailed description is omitted here.

[0017] The mounting seat 34 defines a mounting hole 341 extending along the axis (X) and aligned with and communicating with the through hole 330, and has an annular groove 342 surrounding the axis (X) and formed in a wall defining the mounting hole 341.

[0018] In this embodiment, the air inflation unit 4 includes an inflation valve 41 connected to the main body unit 3. The inflation valve 41 has an elastic valve body 411 inserted into the mounting hole 341 through the through hole 330 and defining an inflation hole 410, and an annular flange 412 formed on an outer surface of the elastic valve body 411 and received in the annular groove 342.

[0019] With reference to the Fig. 5 and Fig. 6 in combination with the Fig. 2 and Fig. 3, the elastic valve body 411 is between a closed state (see Fig. 2) and an open state (see Fig. 5) changeable.

[0020] Since the through-hole 330 of the structural reinforcement layer 33 and the mounting hole 341 of the mounting seat 34 are slightly smaller than the shape of the elastic valve body 411, the elastic valve body 411 can be pressed into and positioned in the through-hole 330 and the mounting hole 341 when the elastic valve body 411 is inserted into the mounting hole 341. When the elastic valve body 411 is in the closed state, the inflation hole 410 is closed by the elastic body 411 to block the communication between the inflation space 31 and the outside. As shown in Fig. As shown in Figure 5, an inflation needle 42 is inserted through the inflation port 410 to open the elastic valve body 411. After the inflation needle 42 is connected to an inflation device (not shown), air can be supplied into the inflation chamber 31 through the inflation needle 42, or air in the inflation chamber 31 can be discharged through the inflation needle 42.

[0021] By simply passing air into and out of the inflation chamber 31 through the inflation valve 41, the inflatable element 32 can be switched between the inflated and deflated states. In the inflated state, the amount of air filled into the inflation chamber 31 can be controlled to adjust the air pressure inside the main body unit 3.

[0022] When the inflatable element 32 is in the inflated state and the air pressure in the inflation chamber 31 is closer to 35 psi, the inflatable element 32 will expand more and its overall hardness will be high (see Fig. 2 and Fig. 4).

[0023] When the inflatable member 32 is inflated and the air pressure in the inflation chamber 31 is closer to or less than 10 psi, although the overall hardness thereof is lower than when the air pressure is closer to 35 psi, the main body unit 3 of the muscle relaxation device of this invention can allow a user to perform rolling and pressing actions on the device through any part of their body and more closely conform to the curves of various parts of their body. Since the structural reinforcement layer 33 has good external and internal pressure resistance, the entire device can maintain the required structural strength and generate sufficient internal pressure to massage muscles or stimulate irregularly arranged myofascia.Furthermore, due to the structural reinforcement layer 33, if the main body unit 3 is accidentally damaged by an external force, there will be no immediate explosion due to the high air pressure inside the inflatable element 32, but only a gradual release of air from it. Therefore, the safety of using the device of this disclosure can be greatly increased.

[0024] It's worth noting that the predetermined length (L) of the main body unit 3 ranges from 5 inches to 50 inches to allow the main body unit 3 to sufficiently span the user's entire back. Therefore, the main body unit 3 can be positioned parallel or perpendicular to the user's spine, making it suitable for massaging the user's back. Furthermore, the main body unit 3 is more stable when rolled along the user's thighs. The predetermined width (D) of the main body unit 3 ranges from 2 inches to 15 inches, allowing the main body unit 3 to provide stretching, compression, and other functions according to the user's different positions or needs. The main body unit 3 weighs from 100 grams to 6000 grams, with the most ideal weight being 1100 grams.Therefore, the main body unit 3 can be picked up and held by the user not only for muscle relaxation but also for muscle endurance training.

[0025] When the inflatable element 32 is in the deflated state, the air in the inflation space 31 can be discharged through the inflation needle 42, so that the main body unit 3 can be compressed and folded to facilitate its storage and transportation (see Fig. 5 and Fig. 6).

[0026] It should be noted that the main body unit 3 is not limited to having only the structural reinforcement layer 33 wrapped around the outer surface of the inflatable element 32. In other variants of this embodiment, a contact layer 30 may be covered on an outer surface of the structural reinforcement layer 33, as shown in Fig. 7. The contact layer 30 is made of a polymer material (e.g., TPE material, EVA foam, rubber, synthetic adhesive material, etc.) and has a plurality of protrusion structures 301 and a plurality of groove structures 302 formed and arranged on its outer surface to enhance the massage effect. In actual implementation, the contact layer 30 may not include the protrusion and groove structures 301, 302, but may include a layer of woven or mesh fabric attached to an outer surface of the polymer material to form the contact layer 30, or a woven or mesh fabric may be directly laid on the outer surface of the structural reinforcement layer 33 to form the contact layer 30. Therefore, the formation of the contact layer 30 on the outer surface of the structural reinforcement layer 33 is not limited to the described embodiment.

[0027] The second embodiment of the muscle relaxation device of the present invention similarly comprises the main body unit 3 and the air inflation unit 4, and differs from the first embodiment in that the main body unit 3 of the second embodiment includes two mounting seats 34, 34', a contact layer 30, and a support 35. The mounting seats 34, 34' are respectively connected to the two ends 321 of the inflatable element 32 of the main body unit 3. The mounting seat 34 has a similar structure to that described in the first embodiment.The mounting seat 34' has the mounting hole 341 defined by a cylindrical wall 3411 and an end wall 3412 connected to an inner end of the cylindrical wall 3411, and further has a first through-hole 3413 formed in the end wall 3412 and communicating with the mounting hole 341 along the axis (X), and a second through-hole 3414 formed in the end wall 3412, radially spaced from the first through-hole 3413 and communicating with the mounting hole 341. The two ends 331 of the structural reinforcement layer 33 are each provided with a through-hole 330. The contact layer 30 covers an outer surface of the structural reinforcement layer 33 and has two ends 300 opposite each other along the axis (X) and each provided with a through hole 303.The through-hole 303 in each end 300 of the contact layer 30 is aligned with and communicates with the through-hole 330 in one of the ends 331 of the structural reinforcement layer 33 and the mounting hole 341 of a corresponding one of the mounting seats 34, 34'. The carrier 35 has a carrier body 351 that is inserted through the corresponding through-holes 303 and 330 into the mounting hole 341 of the mounting seat 34', and an annular flange 352 formed on an outer surface of the carrier body 351 and received in the annular groove 342 of the mounting seat 34'. The carrier body 351 has an L-shaped cross-section with a long body portion 3511 extending along the axis (X) and a short body portion 3513 extending transversely to the long body portion 3511.The long body portion 3511 extends partially through the first through-hole 3413 into the inflation chamber 31 and defines a first insertion hole 3512 extending along the axis (X) and communicating with the inflation chamber 31 and the outside. The short body portion 3513 defines a second insertion hole 3514 extending parallel to the first insertion hole 3512 and communicating with the inflation chamber 31 through the second through-hole 3414 and the outside.

[0028] The air inflation unit 4 of this embodiment further includes an inflator 43 inserted into the first insertion hole 3512 and a valve assembly 44 inserted into the second insertion hole 3514.

[0029] The inflator 43 includes an air cylinder 431 communicating with the inflation chamber 31 and the outside, and a piston rod 432 movably inserted into the air cylinder 431 along the axis (X). The piston rod 432 has a rod body 433, a grip portion 434 disposed at one end of the rod body 433, a plug portion 435 disposed at the other, opposite end of the rod body 433, and two stopper portions 436 formed on the rod body 433 near the grip portion 434 and opposite each other in a direction transverse to the axis (X). The air cylinder 431 has two restricting portions 437 extending inwardly and radially from one end thereof to respectively block the stopper portions 436, and an air outlet 438 located at the other, opposite end thereof.As the piston rod 432 moves relative to the air cylinder 431, air is supplied from the outside into the inflation chamber 31. Since the principle of air inflation is well known in the art, a detailed description is omitted here for the sake of brevity. In this embodiment, the air cylinder 431 is attached to the long body portion 3511 of the support body 351 by adhesive bonding.

[0030] In this embodiment, the valve assembly 44 is a pressure relief valve and includes a valve seat 441 defining a flow channel 440, a valve stem 442 movably inserted into the flow channel 440, and an elastic member 443 disposed between the valve stem 442 and the valve seat 441 to bias the valve stem 442 to close the flow channel 440. In this embodiment, the valve seat 441 is attached to the short body portion 3513 of the support body 351 by adhesive bonding.

[0031] To inflate the main body unit 3 of this embodiment, it is only necessary to rotate the handle portion 434 to move the stopper portions 436 away from the restricting portions 437, after which the piston rod 432 can be pulled and pushed back and forth along the axis (X) to drive air into the inflation space 31. To discharge the air from the main body 3, it is only necessary to press the valve stem 442 to open the flow channel 440, and the air in the inflation space 31 can be discharged to the outside through the flow channel 440. With this configuration, it is not only possible to inflate or deflate the main body unit 3 anytime and anywhere, but also to control the amount of air filled into the inflation space 31 to adjust the air pressure in the inflation space 31.It should be further noted that in the second embodiment, the inflation valve 41 can also be used to deflate the air as described in the first embodiment, depending on the actual usage requirements of the user, and is not limited to that described here.

[0032] The third embodiment of the muscle relaxation device of the present disclosure similarly includes the main body unit 3 and the air inflation unit 4 and is substantially identical to the second embodiment, but differs from the second embodiment in that the main body unit 3 further includes a bushing 36, and the support body 351 of the support 35 engages the mounting seat 34'. The support body 351 has an annular base wall 350 that engages the annular groove 342, and a cylindrical wall 354 that extends from the base wall 350 into the inflation space 31 along the axis (X) and defines a receiving hole 355. The support body 351 further has an externally threaded portion 356 provided at an end of the cylindrical wall 354 opposite the base wall 350, forming a through hole 357.The bushing 36 is inserted into the mounting hole 341 of the mounting seat 34' through one of the through-holes 303 in the contact layer 30 and the corresponding one of the through-holes 330 in the structural reinforcement layer 33, and has a surrounding wall 361 surrounding the axis (X) and defining a receiving space 362, an abutment portion 363 abutting the base wall 350 of the support body 351, an outer end portion 364 opposite the abutment portion 363 along the axis (X), a movement space 365 recessed by an inner annular surface of the abutment portion 363, and two engagement grooves 366 recessed by the outer end portion 364 and radially spaced from each other. In this embodiment, the abutment portion 363 is bonded to the base wall 350 of the support body 351.

[0033] The inflation unit 4 of this embodiment further includes a hollow knob 45 connected to the inflator 43 and received in the receiving space 362 of the socket 36. The air cylinder 431 of the inflator 43 is inserted into the receiving hole 355 of the support body 351 and screwed to the externally threaded portion 356. Its piston rod 432 is retractably inserted into the air cylinder 431, and its handle portion 434 is attached to one end of the piston rod 432, which extends into the hollow knob 45 and detachably abuts the socket 36. The inflator 43 further includes an elastic member 439 fitted onto the piston rod 432 and having two opposite ends, each of which abuts the handle portion 434 and the air cylinder 431. The air cylinder 431 has a threaded bore 4311 which is screwed into the external threaded portion 356.The grip portion 434 has two projections 4341 formed on two sides thereof, respectively, which are opposite to each other in the direction transverse to the axis (X) and are each slidably movable in the engaging grooves 366. The configurations of the engaging grooves 366 and the projections 4341 are also known in the art, so a detailed description thereof will be omitted here.

[0034] In this embodiment, the rotary knob 45 is a stepped hollow cylinder and has a gripping portion 451, an engaging portion 452 opposite to the gripping portion 451 and adhering to the air cylinder 431, and an annular projection 453 projecting outwardly and radially from the engaging portion 452 and received in the moving space 365.

[0035] The inflator 43 is movable relative to the external threaded portion 356 of the support body 351 between an inflation position (see Fig. 13) and an emptying position (see Fig. 14). In the inflation position, the threaded hole 4311 of the inflator 43 is hermetically screwed to the externally threaded portion 356 to block the passage of air. In the deflation position, the threaded hole 4311 of the inflator 43 is loosely engaged with the externally threaded portion 356 to form a gap therebetween for the passage of air, so that the through hole 357 in the externally threaded portion 356 can communicate with the receiving hole 355.

[0036] To inflate the main body unit 3 of this embodiment, it is only necessary to rotate the handle portion 434 of the inflator 43 to disengage its projections 4341 from the respective engagement grooves 366 and thereby separate the handle portion 434 from the socket 36, as shown in Fig. 13, after which the piston rod 432 is moved back and forth along the axis (X) to blow air into the inflation chamber 31. To deflate the main body 3, a user's finger is sufficient to rotate the handle portion 451 of the rotary knob 45 and move and release the air cylinder 431 of the inflator 43 from the external thread portion 356 of the support body 351, thereby bringing the inflator 43 into the deflation position, as shown in Fig. 14. This allows the air in the inflation chamber 31 to flow through the gap between the external threaded portion 356 and the threaded hole 4341 into the receiving hole 355 and exit from the main body unit 3 after passing through the receiving space 362 of the bushing 36 (see arrows in Fig.). Since the external thread portion 356 has a slightly conical shape, the gap is formed between the external thread portion 356 and the threaded hole 4311 due to the size match between them when the air cylinder 431 is rotated to move outward away from the external thread portion 356. Since the internal structure of the air cylinder 431 is well known in the art, a detailed description will be omitted here. It should also be noted that in the third embodiment, the inflation valve 41 can be used for deflation as described in the first embodiment, depending on the actual usage requirement of the user, and is not limited to what is described here.

[0037] From the above description, the advantages of the aforementioned embodiments can be summarized as follows: 1. By providing the structural reinforcement layer 33, which is made of a different material than the inflatable element 32 and completely covers the inflatable element 32, thus having a laminated structure and a composite material design, the internal and external pressure resistance of the inflatable element 32 can be increased, so that the device of this disclosure is not easily damaged. Furthermore, not only can the softness and hardness be adjusted during massage, so that the device of the present invention can better adapt to different parts of the user's body, but also sufficient pressure can be generated to produce different pressure effects on the muscles of different parts of the user's body. Furthermore, the effects of muscle relaxation, rehabilitation, massage, stretching, and Pilates can be integrated into one to reduce costs. 2. When the inflatable member 32 is in the deflated state, the air in the inflation space 31 can be released, so that the main body unit 3 can be compressed and folded for convenient storage and transportation. 3. Since the structural reinforcement layer 33 covers the outer surface of the inflatable member 32, the inflatable member 32 is provided with an additional protective layer during use, so that accidental damage to the inflatable member 32 due to an external force can be avoided and the inflation effect of the inflatable member 32 is not impaired. Moreover, due to the presence of the structural reinforcement layer 33, when the inflatable member 32 is accidentally damaged by an external force, there is no instantaneous explosion due to the high-pressure air inside the inflatable member 32, but only gradual air leakage from the inflation space 31, so the safety of using this invention can be greatly increased. 4. The weight of the device of this invention ranges from 100 grams to 6000 grams, and the most ideal weight thereof is 1100 grams. Therefore, the device of this invention can be used not only for muscle relaxation but also for muscle endurance training.

[0038] In the above description, for purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that one or more other embodiments may be practiced without some of these specific details. It should also be understood that reference throughout this description to "an embodiment," "one embodiment," an embodiment with an ordinal number, etc., means that a particular feature, structure, or characteristic may be included in the practice of the invention. In the description, various features are sometimes grouped into a single embodiment, figure, or description in order to streamline the disclosure and facilitate understanding of various inventive aspects; this does not imply that each of these features must be practiced with the presence of all other features.In other words, if the implementation of one or more features or specific details does not interfere with the implementation of one or more other features or specific details, then that one or more features may be singled out and implemented alone without the other or other features or specific details. It should further be noted that one or more features or specific details from one embodiment may be implemented together with one or more features or specific details from another embodiment where appropriate in the practice of the invention.

Claims

[1] A muscle relaxation device comprising: a main body unit (3) having an axis (X), a predetermined length (L) along the axis (X) and a predetermined width (D) perpendicular to the axis (X); characterized by that the main body unit (3) includes an inflatable element (32) defining an inflation space (31), and a structural reinforcement layer (33) covering an outer surface of the inflatable element (32) and made of a material different from a material of the inflatable element (32), wherein the inflatable element (32) is variable between an inflated state in which the air pressure in the inflation space (31) is in the range of 2 psi to 35 psi, and a deflated state in which the air pressure in the inflation space (31) is less than 2 psi; and an air inflation unit (4) connected to the main body unit (3) for directing air into and out of the inflation space (31). [2] Muscle relaxation device according to claim 1, characterized by that the predetermined length (L) is in the range of 5 inches to 50 inches and the predetermined width (D) is in the range of 2 inches to 15 inches. [3] The muscle relaxation device of claim 2, further comprising a contact layer (30) covering an outer surface of the structural reinforcement layer (33). [4] Muscle relaxation device according to claim 3, characterized by that the contact layer (30) is made of a polymer material. [5] Muscle relaxation device according to claim 1, characterized bythat the main body unit (3) further comprises at least one mounting seat (34, 34') connected to the inflatable element (32), wherein the structural reinforcement layer (33) has two ends (331) opposite each other along the axis (X) and formed with a through hole (330) in at least one of the two ends (331), wherein the at least one mounting seat (34, 34') defines a mounting hole (341) extending along the axis (X) and communicating with the through hole (330), and has an annular groove (342) surrounding the axis (X) and formed in a wall defining the mounting hole (341), wherein the air inflation unit (4) is inserted into the mounting hole (341) through the through hole (330) and has at least one annular flange (412) formed on an outer surface thereof and in the annular groove (342) is included. [6] Muscle relaxation device according to claim 5, characterized by in that the air inflation unit (4) includes an inflation valve (41) connected to the main body unit (3) and having an elastic valve body (411) inserted into the mounting hole through the through hole (330) and defining an inflation hole (410), wherein the at least one annular flange (412) is formed on an outer surface of the elastic valve body (411), the elastic valve body (411) is changeable between a closed state in which the inflation hole (410) is closed by the elastic valve body (411) to block communication between the inflation space (31) and the outside, and an open state in which the inflation hole (410) is opened to allow air into and out of the inflation space (31). [7] Muscle relaxation device according to claim 6, characterized bythat the air inflation unit (4) further comprises an inflation device (43) arranged on the main body unit (3) for supplying air from the outside into the inflation space (31). [8] Muscle relaxation device according to claim 5, characterized bythat the main body unit (3) further comprises a carrier (35) which is inserted into the mounting hole (341) of the at least one mounting seat (34, 34') through the through hole (330) and which has at least one annular flange (352) formed on an outer surface of the carrier (35) and received in the annular groove (342), as well as two insertion holes (3512, 3514) communicating with the inflation space (31) and the outside, wherein the air inflation unit (4) comprises an inflator (43) inserted into one of the insertion holes (3512, 3514) of the carrier (35) for introducing air from the outside into the inflation space (31), and a valve assembly (44) inserted into the other of the insertion holes (3512, 3514) for introducing air into the inflation space (31) to direct and distribute to the outside world. [9] Muscle relaxation device according to claim 5, characterized byin that the at least one mounting seat (34, 34') comprises two mounting seats (34, 34'), wherein the inflatable element (32) has two ends (321) which are opposite one another along the axis (X), wherein the two mounting seats (34, 34') are respectively connected to the two ends (321) of the inflatable element (32), wherein the air inflation unit (4) comprises an inflator (43) which is inserted into the mounting hole (341) of one of the mounting seats (34, 34') in order to direct air from the outside into and out of the inflation space (31), and an inflation valve (41) which is inserted into the mounting hole (341) of the other of the mounting seats (34, 34'). [10] Muscle relaxation device according to claim 8, characterized byin that the inflation device (43) comprises an air cylinder (431) which is connected to the inflation chamber (31) and the outside, and a piston rod (432) which is movably inserted into the air cylinder (431) along the axis (X) and has a handle portion (434), wherein the valve arrangement (44) has a valve seat (441) which defines a flow channel (440), a valve stem (442) which is movably inserted into the flow channel (440), and an elastic element (443) which is arranged between the valve stem (442) and the valve seat (441) in order to bias the valve stem (442) to close the flow channel (440). [11] Muscle relaxation device according to claim 9, characterized bythat the main body unit (3) further comprises a support (35) inserted into the mounting hole (341) of one of the mounting seats (34, 34') and having a support body (351) engaged with the one of the mounting seats (34, 34'), wherein the support body (351) has a cylindrical wall (354) extending into the inflation space (31) along the axis (X) and defining a receiving hole (355), and an externally threaded portion (356) provided at an end of the cylindrical wall (354) opposite to the one of the mounting seats (34, 34') and defining a through hole (357), wherein the air inflation unit (4) comprises the inflator (43) rotatably arranged in the support body (351) and a rotary knob (45) connected to the inflator (43), wherein the inflator (43) relative to the external thread portion (356) between an inflation position,in which the inflator (43) is in airtight contact with the external threaded portion (356) to block the passage of air, and a deflation position in which the inflator (43) is detached from the external threaded portion (356) to form a gap therebetween for the passage of air, [12] Muscle relaxation device according to claim 1, characterized by that the structural reinforcement layer (33) is made of at least one of the following materials: yarn, fabric, PVC mesh, chemical fabric and nylon. [13] Muscle relaxation device according to claim 1, characterized by that the inflatable element (32) has at least one annular projection (322) extending from an inner surface thereof. [14] A muscle relaxation device comprising: a main body unit (3) which is cylindrical and has an axis (X), and which has a predetermined length (L) along the axis (X) and a predetermined width (D) perpendicular to the axis (X); characterized by , that: the main body unit (3) includes an inflatable element (32) made of rubber or synthetic rubber, which defines an inflation space (31), a structural reinforcement layer (33) covering an outer surface of the inflatable element (32) and made of a material different from a material of the inflatable element (32), and a contact layer (30) covering an outer surface of the structural reinforcement layer (33), wherein the inflatable element (32) is variable between an inflated state in which the air pressure in the inflation space (31) is in the range of 2 psi to 35 psi, and a deflated state in which the air pressure in the inflation space (31) is less than 2 psi; and an air inflation unit (4) connected to the main body unit (3) for directing air into and out of the inflation space (31).

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