CN214971497U

CN214971497U - Intelligent chest developer for body building

Info

Publication number: CN214971497U
Application number: CN202120518519.4U
Authority: CN
Inventors: 吴彪
Original assignee: Shenzhen Osmartlink Technology Co Ltd
Current assignee: Shenzhen Osmartlink Technology Co Ltd
Priority date: 2021-03-11
Filing date: 2021-03-11
Publication date: 2021-12-03
Anticipated expiration: 2031-03-11

Abstract

The utility model discloses an intelligence chest expander that body-building was used, intelligence chest expander that body-building was used include stretch cord, elastic protection cover, sensor module, fixed pulley assembly and regulator. Elastic protection sleeve wraps up in the periphery of stretch cord, and elastic protection sleeve is along with the deformation of stretch cord and deformation, and the regulator includes casing and wrapping post, and the wrapping post is located the casing, and the other end of stretch cord penetrates in the casing, and after locating the wrapping post, wear out from the casing, the other end of stretch cord walk around fixed pulley assembly after with casing fixed connection. According to the utility model discloses an intelligence chest expander that body-building was used, when the both ends of stretch cord all received the pulling force, under the effect of pulling force, the stretch cord was around establishing on the wrapping post, and the pulling force is big more, and elastic protection cover can increase the frictional force between stretch cord and the wrapping post to can make the stretch cord fixed for the wrapping post, thereby can promote the length adjustment's of regulator stability, and then can promote the stability of chest expander.

Description

Intelligent chest developer for body building

Technical Field

The utility model relates to a body-building apparatus technical field especially relates to an intelligent chest expander that body-building was used.

Background

The body-building chest expander can help people to exercise muscles, help to shape body curves and effectively improve physical quality, so that the chest expander is deeply loved by vast body-building enthusiasts, and a general chest expander consists of two handles and a rope body rich in elasticity. The body-building chest expander has the characteristics of small occupied area, portability and portability, so that the chest expander can help sporters to perform whole-body exercises such as strength, flexibility, stretching and the like at any time and any place, and is an indoor body-building apparatus with very high degree of freedom. However, the existing fitness chest expander cannot perform data statistics on the exercise process of the sporter when the sporter exercises, and the intelligent degree is not high. When the length of the elastic rope is adjusted, the adjusting buckle has a shearing force effect on the elastic rope, and the elastic rope is easy to break after long-time use.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an intelligence chest expander that body-building was used, the intelligence chest expander that body-building was used has simple structure, long service life's advantage.

According to the utility model discloses intelligence chest expander that body-building was used, include: a bungee cord having elasticity; the elastic protective sleeve wraps the periphery of the elastic rope and deforms along with the deformation of the elastic rope; the sensor assembly is arranged at one end of the elastic rope, a battery, a circuit board and a tension sensor are arranged in the sensor assembly, and the battery and the tension sensor are electrically connected with the circuit board; a fixed pulley assembly; the regulator, the regulator includes casing and wrapping post, the wrapping post is located in the casing, the other end of stretch cord penetrates in the casing, and the duplex winding is located behind the wrapping post, follow the casing is worn out, the other end of stretch cord walk around behind the fixed pulley assembly with casing fixed connection.

According to the utility model discloses intelligence chest expander that body-building was used establishes elastic protective sleeve through the periphery cover at the stretch cord, when the both ends of stretch cord all received the pulling force, under the effect of pulling force, the stretch cord is around establishing on the wrapping post, and the pulling force is big more, the winding force of stretch cord on the wrapping post is big more, elastic protective sleeve can increase the frictional force between stretch cord and the wrapping post, thereby can make the stretch cord fixed for the wrapping post, thereby can promote the stability of the length adjustment of regulator, and then can promote the stability of chest expander.

In some embodiments, the intelligent chest expander for exercise further comprises a first socket for fixing one end of the elastic protection sleeve with one end of the elastic cord and a second socket for fixing the other end of the elastic protection sleeve with the other end of the elastic cord.

In some embodiments, a flocking layer is arranged on one side of the elastic protection sleeve facing the elastic rope; or the peripheral wall of the winding post is a rough surface.

In some embodiments, a flocking layer is arranged on one side of the elastic protection sleeve, which faces away from the elastic rope.

In some embodiments, the housing includes an upper case and a lower case, the upper case and the lower case are connected to define a mounting cavity, one end of the winding post is connected to the lower case, the upper case has a positioning groove therein, and the other end of the winding post is located in the positioning groove.

In some embodiments, the lower case has a screw post extending toward the upper case, the upper case and the lower case are coupled by a screw coupled with the screw post; or, the epitheca has first joint portion, the inferior valve has second joint portion, first joint portion with second joint portion joint, one in first joint portion and the second joint portion is the draw-in groove, and another is the trip.

In some embodiments, the sensor assembly includes a connection shell and a protective shell, the connection shell is connected with the protective shell, the connection shell is connected with one end of the elastic rope, and the circuit board, the battery and the tension sensor are arranged in the protective shell.

In some embodiments, the protective shell has a first cavity and a second cavity, the battery and the circuit board are located in the first cavity, the tension sensor is located in the second cavity, and a support rib is arranged in the second cavity and used for supporting the tension sensor.

In some embodiments, the connection shell has a protrusion toward an end of the protection shell, the protection shell has a groove toward an end of the connection shell, and when the connection shell is connected with the protection shell in a rotating and buckling manner, the protrusion is buckled into the groove along with the rotation of the connection shell.

In some embodiments, the free end of the protrusion has a limiting groove, and the inner bottom wall of the groove body has a limiting convex strip, and the limiting convex strip is embedded in the limiting groove.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural view of a chest expander according to an embodiment of the present invention;

fig. 2 is a partial schematic view of the chest expander of fig. 1;

fig. 3 is a schematic structural view of a lower case of the chest expander according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of an upper case of a chest expander according to an embodiment of the present invention

Figure 5 is a cross-sectional view of a housing of a chest expander according to an embodiment of the invention;

fig. 6 is a schematic structural view of a sensor assembly of a chest expander according to an embodiment of the present invention;

fig. 7 is a schematic structural view of a protective case of the chest expander according to an embodiment of the present invention;

fig. 8 is a schematic structural view of another perspective of the protective case of the chest expander according to the embodiment of the present invention;

fig. 9 is a schematic structural view of a connection case of the chest expander according to an embodiment of the present invention;

fig. 10 is a schematic view of a sensor assembly of a chest expander according to an embodiment of the present invention.

Reference numerals:

the chest-expander 100 is provided with a spring,

the bungee cord 110, the elastic protective sleeve 150, the first sleeve 151,

a sensor assembly 120, a battery 121, a circuit board 123, a tension sensor 124,

a coupling case 125, a protrusion 1251, a stopper groove 1252,

a protective shell 126, a first cavity 1261, a second cavity 1262, a support rib 1263, a groove 1264, a limit convex strip 1265,

the number of steps in fixed sheave assembly 130, adjuster 140,

a shell 141, a hard skeleton 1411, reinforcing ribs 1412, a wire passage 1413, straight line segments 1414, a widened segment 1415, a soft glue layer 1416,

the winding post 142, the upper case 143, the positioning groove 1431, the first catching portion 1432,

the lower shell 144, a second clamping part 1441, a screw post 1442 and a mounting cavity 1443.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

An intelligent chest expander 100 for exercise according to an embodiment of the present invention is described below with reference to fig. 1 to 10.

As shown in fig. 1 and 2, the intelligent chest expander 100 for exercise according to the embodiment of the present invention includes a bungee cord 110, a sensor assembly 120, a fixed pulley assembly 130, an adjuster 140 and an elastic protection sleeve 150.

Specifically, the elastic cord 110 has elasticity, and the elastic protection sleeve 150 wraps the outer periphery of the elastic cord 110, and the elastic protection sleeve 150 deforms along with the deformation of the elastic cord 110. It will be appreciated that when the bungee cord 110 is in a stretched condition, the elastic protection sleeve 150 is stretched as the bungee cord 110 is stretched, i.e., the elastic protection sleeve 150 is also in a stretched condition. The elastic protection sleeve 150 may be a cloth having elasticity.

The sensor assembly 120 is disposed at one end of the elastic cord 110, a battery 121, a circuit board 123 and a tension sensor 124 are disposed in the sensor assembly 120, and the battery 121 and the tension sensor 124 are electrically connected to the circuit board 123. It should be noted that the tension sensor 124 may be configured to detect the tension borne by the elastic cord 110, the tension sensor 124 transmits the detected data to the electrical components on the circuit board 123, and the corresponding electrical components convert the information detected by the tension sensor 124 into an information form readable by the user through data conversion, so that the user can know the tension applied to the chest expander 100. In addition, the battery 121 may supply power to the tension sensor 124 and the electrical components on the circuit board 123.

As shown in fig. 3-5, the adjuster 140 includes a housing 141 and a winding post 142, the winding post 142 being located within the housing 141. The other end of the elastic cord 110 penetrates into the housing 141, winds around the winding post 142, and then penetrates out of the housing 141, the other end of the elastic cord 110 winds around the fixed pulley assembly 130 and then is fixedly connected with the housing 141, and the winding path of the elastic cord 110 is shown by an arrow in fig. 3. It should be noted that, after the other end of the elastic cord 110 passes through the housing 141, it passes through the fixed pulley assembly 130, and then is connected to the housing 141, and the length of the elastic cord 110 can be automatically adjusted by the arrangement of the fixed pulley assembly 130, so as to balance the lengths of the elastic cords 110 on both sides of the fixed pulley assembly 130.

By arranging the winding post 142 in the casing 141 and winding the elastic cord 110 on the winding post 142, when a user feeds a part of the elastic cord 110 into the casing 141 of the adjuster 140, the elastic cord 110 can move relative to the winding post 142, and because the space in the casing 141 is limited, another part of the elastic cord 110 is extruded out of the casing 141 under the driving of the elastic cord 110, so that the distance between the adjuster and one end of the elastic cord 110 can be adjusted, and the length of the tensioner 100 can be adjusted; when the chest expander 100 is used, the two parts of the elastic cord 110 are respectively subjected to tension, and the greater the tension, the greater the winding force of the elastic cord on the winding post, so that the elastic cord 110 can be positioned. In addition, the tension sensor 124 is arranged at one end of the elastic rope 110, so that the tension borne by the elastic rope 110 can be detected, the training condition of a user can be monitored and recorded, and the user can conveniently perform fine planning on the training.

It is understood that the adjuster 140 may divide the elastic cord 110 into two parts, one part is from one end of the elastic cord 110 to the adjuster 140, and the sensor assembly 120 is disposed on the part, so that the user can apply a pulling force to the elastic cord 110 by pulling the sensor assembly 120 during training, and the sensor assembly 120 can detect the magnitude of the pulling force; another portion of bungee cord 110 is from the other end of bungee cord 110 to adjuster 140 where bungee cord 110 passes around fixed pulley assembly 130 and a user may apply tension to bungee cord 110 by pulling fixed pulley assembly 130 during training.

When the chest expander 100 is used, two parts of the elastic cord 110 are respectively subjected to tension, under the action of the tension, the elastic cord 110 is wound on the winding post 142, and the greater the tension is, the greater the winding force of the elastic cord 110 on the winding post 142 is, so that the relative position between the elastic cord 110 and the winding post 142 is difficult to change, and at the moment, the winding post 142 has a positioning effect on the elastic cord 110. It should be noted here that, because the elastic protection sleeve 150 wraps the periphery of the elastic cord 110, the elastic protection sleeve 150 is located between the elastic cord 110 and the wrapping post 142, at this time, the elastic protection sleeve 150 can increase the friction force between the elastic cord 110 and the wrapping post 142, so that the elastic cord 110 is fixed relative to the wrapping post 142, the stability of the length adjustment of the adjuster 140 can be improved, and the stability of the chest expander 100 can be improved.

When the chest expander 100 is in a natural state, the elastic cord 110 is not affected by external force, the elastic cord 110 is wound on the winding posts 142 in a natural state, no force is applied between the winding posts 142 by the elastic cord 110, when a user feeds a part of the elastic cord 110 into the shell 141 of the adjuster 140, the elastic cord 110 can move relative to the winding posts 142, and due to the limited space in the shell 141, the other part of the elastic cord 110 is extruded out of the shell 141 under the driving of the elastic cord 110, so that the distance between the adjuster and one end of the elastic cord 110 can be adjusted, and further the length of the chest expander 100 can be adjusted.

According to the utility model discloses intelligence chest expander 100 that body-building was used, establish elastic protection sleeve 150 through the outer periphery cover at stretch cord 110, when stretch cord 110's both ends all received the pulling force, under the effect of pulling force, stretch cord 110 is around establishing on wrapping post 142, and the pulling force is big more, stretch cord 110 is big more in the winding power on wrapping post 142, elastic protection sleeve 150 can increase the frictional force between stretch cord 110 and the wrapping post 142, thereby can make stretch cord 110 fixed for wrapping post 142, thereby can promote regulator 140's length adjustment's stability, and then can promote chest expander 100's stability.

According to some embodiments of the present invention, as shown in fig. 1 and 2, the intelligent chest expander for exercise further comprises a first pipe sleeve 151 and a second pipe sleeve, the first pipe sleeve 151 is used for fixing one end of the elastic protection sleeve 150 with one end of the elastic rope 110, and the second pipe sleeve is used for fixing the other end of the elastic protection sleeve 150 with the other end of the elastic rope 110. That is, the first sleeve 151 and the second sleeve may be used to maintain a fixed relative position of the bungee cord 110 and the elastic protection sleeve 150 such that when the bungee cord 110 is stretched, the elastic protection sleeve 150 is also stretched; when the bungee cord 110 is repositioned, the elastic sleeve 150 is repositioned accordingly.

To increase the friction between the elastic protective sheath 150 and the elastic cord 110, in some embodiments, the elastic protective sheath 150 is provided with a flocking layer on the side facing the elastic cord 110. In some embodiments, the outer peripheral wall of the winding post 142 is rough, so that the friction between the elastic sheath 150 and the winding post 142 can be increased. Further, the elastic protection sleeve 150 may also be provided with a flocking layer on a side away from the elastic cord 110, so as to enhance the touch feeling, facilitate the use of the user, and avoid discomfort after the elastic cord 110 contacts the skin of the user.

As shown in fig. 4, the housing 141 may be a two-shot injection molded part and includes a hard skeleton 1411 and a soft glue layer 1416 coated on the hard skeleton 1411. It should be noted that the double-shot molding is an injection molding method in the secondary injection molding, and in the process of the two-shot molding process, the injection molding material can be selected from different colors, so that the molding structure can be observed conveniently, and the product quality can be improved conveniently. The molding process of the two-color injection molding is simple, and the hard skeleton 1411 can provide a strong supporting force for the housing 141, so that the overall structural strength of the housing 141 can be improved. In addition, as shown in fig. 3 and 4, the hard skeleton 1411 extends out of a reinforcing rib 1412 towards the inside of the housing 141, the reinforcing rib 1412 defines a thread passing channel 1413, and the part of the elastic cord 110 located in the housing 141 is located in the thread passing channel 1413. On one hand, the rigid structure defining the wire passage 1413 can effectively limit the running direction of the elastic cord 110 in the housing 141, thereby facilitating the position of the adjuster 140; on the other hand, the reinforcing ribs 1412 also have a supporting function, and can effectively reinforce the overall strength of the housing 141.

According to some embodiments of the present invention, as shown in fig. 3 and 4, the wire passage 1413 may include a straight line segment 1414 and a widened segment 1415, the straight line segment 1414 extends along a straight line, the straight line segment 1414 is communicated with the widened segment 1415, the minimum width of the widened segment 1415 is wider than the maximum width of the straight line segment 1414, and the winding post 142 is disposed in the widened segment 1415. It should be noted that the straight section 1414 can define the direction of the bungee cord 110 inside the housing 141; when the elastic cord 110 is wound on the winding post 142, the widened section 1415 needs to occupy a larger space for the elastic cord 110, and the widened section 1415 can be used for accommodating the elastic cord 110 wound on the winding post 142, so as to facilitate the adjustment of the relative position of the housing 141 and the elastic cord 110. Further, for convenience of adjustment, when the elastic cord 110 is wound around the winding post 142, the elastic cord 110 may be wound by one turn.

As shown in FIG. 5, to facilitate installation of bungee cord 110 inside housing 141, in some embodiments, housing 141 may include an upper shell 143 and a lower shell 144. Wherein, the upper shell 143 and the lower shell 144 are connected to define a mounting cavity 1443, one end of the winding post 142 is connected to the lower shell 144, the upper shell 143 has a positioning groove 1431 therein, and the other end of the winding post 142 is located in the positioning groove 1431. It should be noted that, by providing the positioning groove 1431 and disposing the free end of the winding post 142 in the positioning groove 1431, on one hand, the positioning groove 1431 can be used to limit the winding post 142, and on the other hand, the groove wall of the positioning groove 1431 can be used to support the winding post 142, thereby preventing the winding post 142 from being inclined or bent when being pulled by the elastic cord 110.

To facilitate securing the upper and

lower housings

143, 144 together, in some embodiments, as shown in fig. 5, the lower housing 144 has screw posts 1442, the screw posts 1442 extend toward the upper housing 143, and screws are threaded through the upper housing 143 and then engage the screw posts 1442, so that the upper and

lower housings

143, 144 can be assembled together. Whereby the upper case 143 and the lower case 144 can be fixed using screws. To facilitate fixing the screw, a screw post 1442 may be provided on the lower case 144, so that the screw may be fixed using the screw post 1442.

It should be noted that the fixing manner of the upper shell 143 and the lower shell 144 is not limited thereto, as long as it can fixedly connect the upper shell 143 and the lower shell 144 together, for example, as shown in fig. 3 and fig. 4, the upper shell 143 has a first clamping portion 1432, the lower shell 144 has a second clamping portion 1441, the first clamping portion 1432 is clamped with the second clamping portion 1441, one of the first clamping portion 1432 and the second clamping portion 1441 is a clamping slot, and the other is a clamping hook. Further, the first clamping portion 1432 and the second clamping portion 1441 may be multiple, and the multiple first clamping portions 1432 and the multiple second clamping portions 1441 are clamped in a one-to-one correspondence manner. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

According to some embodiments of the present invention, as shown in fig. 6, the sensor assembly 120 may include a connection shell 125 and a protection shell 126, the connection shell 125 is connected to the protection shell 126, the connection shell 125 is connected to one end of the elastic cord 110, and the circuit board 123, the battery 121 and the tension sensor 124 are disposed in the protection shell 126. Therefore, interference between the components in the connection shell 125 and the inside of the protection shell 126 is avoided, and meanwhile, when the components in the protection shell 126 are detached and maintained, the components in the connection shell 125 are not affected, so that the whole service life of the chest expander 100 can be prolonged.

As shown in fig. 10, in some examples, the protective shell 126 has a first cavity 1261 and a second cavity 1262 therein, the battery 121 and the circuit board 123 are located in the first cavity 1261, the tension sensor 124 is located in the second cavity 1262, a support rib 1263 is provided in the second cavity 1262, and the support rib 1263 is used for supporting the tension sensor 124. Therefore, the assembly stability of the tension sensor 124 can be improved, and the detection accuracy of the tension sensor 124 can be improved.

In order to facilitate the connection of the protective shell 126 and the connection shell 125, in the example shown in fig. 7, the connection shell 125 has a protrusion 1251 toward the end of the protective shell 126, the protective shell 126 has a groove 1264 toward the end of the connection shell 125, and when the connection shell 125 is rotatably snap-coupled with the protective shell 126, the protrusion 1251 is rotatably snap-coupled into the groove 1264 following the connection shell 125. It will be appreciated that the projection 1251 may extend in a direction of rotational snap-fit of the protective shell 126, and that upon mounting the connection shell 125 to the protective shell 126, the projection 1251 rotates into the slot 1264 while the connection shell 125 rotates relative to the protective shell 126. When the protrusion 1251 is mated with the groove 1264, the connecting shell 125 is completely assembled with the protective shell 126.

Further, in order to prevent the projection 1251 from coming off the groove body 1264, as shown in fig. 8 and 9, the free end of the projection 1251 has a stopper groove 1252, the inner bottom wall of the groove body 1264 has a stopper protrusion 1265, and the stopper protrusion 1265 is fitted into the stopper groove 1252. From this, through with spacing sand grip 1265 joint in spacing groove 1252, can inject protruding 1251 in cell body 1264 steadily to can promote the assembly stability of connecting shell 125 and protective housing 126, prevent to connect shell 125 and protective housing 126 because of unexpected the breaking away from.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An intelligent chest expander for fitness, comprising:

a bungee cord having elasticity;

the elastic protective sleeve wraps the periphery of the elastic rope and deforms along with the deformation of the elastic rope;

the sensor assembly is arranged at one end of the elastic rope, a battery, a circuit board and a tension sensor are arranged in the sensor assembly, and the battery and the tension sensor are electrically connected with the circuit board;

a fixed pulley assembly;

the regulator, the regulator includes casing and wrapping post, the wrapping post is located in the casing, the other end of stretch cord penetrates in the casing, and the duplex winding is located behind the wrapping post, follow the casing is worn out, the other end of stretch cord walk around behind the fixed pulley assembly with casing fixed connection.

2. The intelligent chest expander for exercise according to claim 1, further comprising a first socket for securing one end of said elastic protection sleeve to one end of said elastic cord and a second socket for securing the other end of said elastic protection sleeve to the other end of said elastic cord.

3. The intelligent chest expander for fitness according to claim 1, wherein a flocking layer is arranged on one side of the elastic protection sleeve facing the elastic rope;

or the peripheral wall of the winding post is a rough surface.

4. An intelligent chest expander for exercise according to claim 3 and wherein said elastic protective sleeve is provided with a flocked layer on the side facing away from said elastic cord.

5. The intelligent chest expander for fitness according to claim 1, wherein said housing comprises an upper shell and a lower shell, said upper shell and said lower shell being connected to define a mounting chamber,

one end of the wrapping post is connected with the lower shell, a positioning groove is formed in the upper shell, and the other end of the wrapping post is located in the positioning groove.

6. The intelligent chest expander for exercise according to claim 5, wherein said lower casing has screw posts extending toward said upper casing, said upper casing and said lower casing being connected by screws, said screws being connected with said screw posts;

or, the epitheca has first joint portion, the inferior valve has second joint portion, first joint portion with second joint portion joint, one in first joint portion and the second joint portion is the draw-in groove, and another is the trip.

7. The intelligent chest expander for fitness according to claim 1, wherein the sensor assembly comprises a connecting shell and a protective shell, the connecting shell is connected with the protective shell, the connecting shell is connected with one end of the elastic rope, and the circuit board, the battery and the tension sensor are arranged in the protective shell.

8. An intelligent chest expander for exercise according to claim 7 and wherein said protective casing has a first cavity and a second cavity, said battery and said circuit board being located in said first cavity, said tension sensor being located in said second cavity, said second cavity having a support rib therein, said support rib being adapted to support said tension sensor.

9. An intelligent chest expander for fitness according to claim 7, wherein the end of the connection shell facing the protective shell has a protrusion, the end of the protective shell facing the connection shell has a groove, and when the connection shell is in rotary snap-fit connection with the protective shell, the protrusion is rotationally snap-fit into the groove along with the connection shell.

10. An intelligent chest expander for body building according to claim 9, wherein the free end of the protrusion has a limiting groove, the inner bottom wall of the groove body has a limiting convex strip, and the limiting convex strip is embedded in the limiting groove.