CN113713323A

CN113713323A - Weight-adjustable dumbbell

Info

Publication number: CN113713323A
Application number: CN202110883244.9A
Authority: CN
Inventors: 罗谢同; 何展飞
Original assignee: Jiangxi Eqi Industrial Co ltd
Current assignee: Jiangxi Eqi Industrial Co ltd
Priority date: 2021-08-02
Filing date: 2021-08-02
Publication date: 2021-11-30

Abstract

A weight-adjustable dumbbell comprises a handle, a first weight portion and a second weight portion, wherein the first weight portion and the second weight portion are respectively arranged at two ends of the handle, the first weight portion and the second weight portion respectively comprise a plurality of dumbbell pieces, each dumbbell piece comprises a mounting hole in the middle and an open slot which extends outwards from the mounting hole and penetrates to the outside, and the width of the open slot is smaller than the diameter of the mounting hole; the dumbbell with the adjustable weight further comprises an adjusting mechanism, the adjusting mechanism comprises a rotating mechanism, a transmission shaft, a first transmission shaft sleeve and a second transmission shaft sleeve, the rotating mechanism is arranged on the outer side of the first counterweight portion, the first transmission shaft sleeve and the second transmission shaft sleeve axially move under the driving of the transmission shaft, and the first transmission shaft sleeve and the second transmission shaft sleeve are inserted into or separated from part or all of the installation holes of the dumbbell pieces towards two ends, so that the dumbbell pieces are left or separated from the first counterweight portion and the second counterweight portion, and the weight of the dumbbell is adjusted. The weight-adjustable dumbbell provided by the invention is more convenient to adjust and operate.

Description

Weight-adjustable dumbbell

Technical Field

The invention relates to the technical field of fitness products, in particular to a weight-adjustable dumbbell.

Background

The existing dumbbell with adjustable weight on the market can solve the problem that the existing dumbbell with integrally formed weight cannot adjust the weight, but the existing dumbbell with adjustable weight has complex operation when the weight is adjusted, cannot satisfy users, and is not good in use experience.

The foregoing description is provided for general background information and is not admitted to be prior art.

Disclosure of Invention

The invention aims to provide a weight-adjustable dumbbell convenient to operate.

The invention provides a weight-adjustable dumbbell, which comprises a handle part, wherein the handle part comprises a handle, a first counterweight part and a second counterweight part, the first counterweight part and the second counterweight part are respectively arranged at two ends of the handle, the first counterweight part and the second counterweight part respectively comprise a plurality of dumbbell pieces, each dumbbell piece comprises a mounting hole positioned in the middle and an open slot which extends outwards from the mounting hole and penetrates to the outside, and the width of the open slot is smaller than the diameter of the mounting hole; the weight-adjustable dumbbell further comprises an adjusting mechanism, the adjusting mechanism comprises a rotating mechanism, a transmission shaft, a first transmission shaft sleeve and a second transmission shaft sleeve, the rotating mechanism is arranged on the outer side of the first counterweight part, and the rotating mechanism is fixedly connected with the transmission shaft and used for driving the transmission shaft to rotate; the first transmission shaft sleeve and the second transmission shaft sleeve are sleeved on the transmission shaft, and the transmission shaft is meshed with the first transmission shaft sleeve and the second transmission shaft sleeve to enable the transmission shaft to drive the first transmission shaft sleeve and the second transmission shaft sleeve to move; the outer diameters of the first transmission shaft sleeve and the second transmission shaft sleeve are larger than the width of the opening groove and smaller than the diameter of the mounting hole, and the first transmission shaft sleeve and the second transmission shaft sleeve are also provided with rotation stopping structures, so that the first transmission shaft sleeve and the second transmission shaft sleeve axially move under the driving of the transmission shaft due to the limitation of the rotation stopping structures, and are inserted into or separated from part or all of the mounting holes of the dumbbell pieces towards two ends, and the dumbbell pieces are left or separated from the first counterweight part and the second counterweight part, so that the weight of the dumbbell is adjusted.

Further, the transmission shaft is a screw rod, the first transmission shaft sleeve and the second transmission shaft sleeve are respectively a first nut and a second nut, external threads are arranged at two ends of the screw rod, and internal threads matched with the external threads are arranged inside the first nut and the second nut.

Furthermore, in the adjusting mechanism, the gear ring rotates for one circle, and the first transmission shaft sleeve and the second transmission shaft sleeve axially move for a distance which is multiple times of the center distance between two adjacent dumbbell pieces.

Further, rotary mechanism includes planet wheel drive mechanism, planet wheel drive mechanism includes intermeshing's ring gear, sun gear, planet wheel, the ring gear is as the operation end, sun gear fixed connection the transmission shaft makes the ring gear pass through the sun gear drives the transmission shaft is rotatory

Furthermore, the adjusting mechanism comprises an operating part, the operating part is fixedly connected with the gear ring, the gear ring can be driven to rotate when the operating part rotates, and the operating part is provided with a plurality of weight scales and used for displaying the weight of the dumbbell corresponding to the position of the operating part.

Furthermore, the rotation stopping structure comprises a rotation stopping pin arranged at the periphery of the first transmission shaft sleeve and the second transmission shaft sleeve, the handle is correspondingly provided with a rotation stopping groove, and the first transmission shaft sleeve and the second transmission shaft sleeve are limited to rotate along with the transmission shafts through the matching of the rotation stopping groove and the rotation stopping pin.

Further, the handle is of a hollow structure, and the transmission shaft is located in the handle and can rotate relatively but cannot move axially.

Furthermore, the weight-adjustable dumbbell is provided with a prompting mechanism outside the second counterweight part, the prompting mechanism comprises a fixing part, an elastic part, a ball and a rotating part, the rotating part is fixed on the transmission shaft and can rotate along with the transmission shaft, the rotating part is provided with a plurality of round holes, the circle center of a circle formed by the circle centers of the round holes is located on the axis of the transmission shaft, and the ball is movably fixed on the fixing part, is pressed by the elastic part and is located on the rotating path of the round holes, so that when the dumbbell is adjusted to a preset weight, the ball is pushed by the elastic part to fall into the round holes.

Further, dumbbell with adjustable weight still includes the base, is used for placing handle portion, it has the plectane of a plurality of tooth's sockets to rotate the piece for periphery evenly distributed, dumbbell with adjustable weight is in the second counter weight portion outside is equipped with self-locking mechanism, self-locking mechanism includes locking piece, resilience piece, the locking piece includes upper stop portion and support portion down, locking piece rotationally fixes the mounting, resilience piece is located between locking piece and the mounting, locking piece and resilience piece interconnect make resilience piece can drive upper stop portion is internal rotation towards, block in the tooth's socket, and work as handle portion place in behind the base, support portion down by the base is contradicted and is driven upper stop portion is toward outer rotatory, makes upper stop portion break away from the tooth's socket.

Furthermore, the first counterweight portion and the second counterweight portion respectively comprise a dumbbell piece mounting seat for placing dumbbell pieces, and the fixing piece is fixed on the dumbbell piece mounting seat.

According to the weight-adjustable dumbbell provided by the invention, the rotating mechanism is arranged on the outer side of the first counterweight part, the weight of the dumbbell is adjusted by matching the transmission shaft with the first transmission shaft sleeve and the second transmission shaft sleeve, the operation is very convenient, and excellent use experience can be brought to a user. In addition, the planetary gear transmission mechanism is adopted as the rotating mechanism, the weight adjusting operation is labor-saving, and the use experience of a user can be further improved.

Drawings

Fig. 1 is a perspective combination view of a weight-adjustable dumbbell according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of the weight-adjustable dumbbell shown in fig. 1.

FIG. 3 is another exploded perspective view of the weight adjustable dumbbell of FIG. 1 (without the dumbbell sheet and base shown).

Fig. 4 is an exploded perspective view of the prompting mechanism and the self-locking mechanism in the weight-adjustable dumbbell shown in fig. 1.

FIG. 5 is a perspective view of the locking tab of the self-locking mechanism of FIG. 4.

Fig. 6 is a sectional view of a part of elements of the weight-adjustable dumbbell shown in fig. 1.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

As shown in fig. 1, in the present embodiment, a weight-adjustable dumbbell includes a handle portion 1 and a base 3, and the base 3 is used for placing the handle portion 1.

As shown in fig. 1 to 3, in this embodiment, the handle portion 1 includes a handle 11, a first weight portion 12 and a second weight portion 13 respectively disposed at two ends of the handle 11, an adjusting mechanism 14, a prompting mechanism, and a self-locking mechanism. In the present embodiment, the first weight 12 is a weight located on the right side, and the second weight 13 is a weight located on the left side. Of course, the first weight 12 may be a weight on the left side, and the second weight 13 may be a weight on the right side, which may be adjusted according to design requirements.

The handle 11 includes a handle main body 110, and a first side plate 114 and a second side plate 115 fixed to both ends of the main body 110 by welding or screwing. The main body 110 is a hollow tubular structure, and a plurality of axially extending rotation-stopping grooves 111 are correspondingly formed in the main body and penetrate through the handle 11 (including a first side plate 114 and a second side plate 115), so that the handle 11 forms a hollow structure.

The first weight portion 12 includes a first dumbbell sheet receptacle 121 and a plurality of dumbbell sheets 122 that can be seated in the first dumbbell sheet receptacle 121. The first dumbbell plate holder 121 includes a first outer baffle 1212 and first and

second spacers

1213, 1214 secured to the inside of the first outer baffle 1212. The first side plate 114 of the handle 11 is fixed to the inside of the first separator 1213 and the second separator 1214. First spacing element 1213 and second spacing element 1214 each have a plurality (4 in this embodiment) of notches 1215 for spacing each dumbbell sheet 122. The second weight portion 13 includes a second dumbbell sheet mount 131 and a plurality of dumbbell sheets 132 that can be seated in the second dumbbell sheet mount 131. Second dumbbell plate mount 131 includes a second outer baffle 1312 and third and

fourth spacers

1313 and 1314 fixed to the inside of second outer baffle 1312. The second side plate 115 of the handle 11 is fixed to the inner sides of the third and

fourth spacers

1313 and 1314. The third and

fourth spacers

1313, 1314 are provided with a plurality (4 in this embodiment) of grooves 1315 to separate and retain the dumbbell plates 122.

As shown in fig. 2, each dumbbell piece 122 is a circular piece, and has a mounting hole 1221 in the middle, two sides of the mounting hole 1221 extend outward, one side of the mounting hole forms an open slot 1222 penetrating to the outside, and the other side forms a U-shaped slot 1223 not penetrating to the outside. The

open slots

1222 and 1223 correspond to the first or

third spacers

1213, 1313 and the second or

fourth spacers

1214, 1314, respectively, to limit the separation and rotation of the dumbbell plates 122. The widths of the open slot 1222 and the U-shaped slot 1223 are both smaller than the diameter of the mounting hole 1221.

As shown in fig. 3, the adjusting mechanism 14 includes a planetary gear mechanism 141, a transmission shaft 142, a first transmission shaft sleeve 143, a second transmission shaft sleeve 144, a planetary gear carrier 145, a ring gear carrier 146, and a first cover 147.

The planetary gear transmission mechanism 141 is provided outside the first weight portion 12, and includes a ring gear 1411, a sun gear 1412, and planetary gears 1413 that are meshed with each other. The ring gear 1411 serves as the operating end, and the planet wheels 1413 are fixed to the first dumbbell sheet holder 121 by a planet wheel carrier 145. The sun gear 1412 is connected with the transmission shaft 142, and when the gear ring 1411 is rotated, the gear ring 1411 can drive the transmission shaft 142 to rotate through the sun gear 1412. The ring gear 1411 is fixed to the ring gear bracket 146 by screws. In this embodiment, the planetary gear transmission mechanism 141 is used as a rotation mechanism to drive the transmission shaft 142 to rotate, which saves more labor and is smoother to operate compared with a method of directly driving a rotation shaft to rotate. Of course, in other embodiments, the rotating shaft can be directly driven to rotate, and other rotating mechanisms, such as a common gear train, can also be adopted.

The first cover 147 is fixed to the ring gear 1411 by screws, the first cover 147 serves as an operating member of the adjustment mechanism 14, the ring gear 1411 is rotated by rotating the first cover 147, and the first cover 147 and the ring gear support 146 form an accommodating space for accommodating the planetary gear mechanism 141 therein.

The first cover 147 is provided with weight scales around for displaying the weight of the dumbbell corresponding to the position of the first cover. In this embodiment, there are five scale values, 5 (pounds), 10 (pounds), 15 (pounds), 20 (pounds), 25 (pounds), which represent the weight of no dumbbell pieces, plus two dumbbell pieces, plus four dumbbell pieces, plus six dumbbell pieces, plus eight dumbbell pieces, respectively, when the scale is uppermost. Of course, the scale may represent other units of weight (e.g., kilograms) and different numbers (e.g., 10, 20, etc.) may be provided. The number of scale values is also not limited to five, but generally corresponds to the number of dumbbell pieces, which is equal to the number of dumbbell pieces on one side plus 1 (since the initial value is the weight of no dumbbell pieces).

Of course, in other embodiments, other configurations may be used as the operating member of the adjustment mechanism 14, such as a lever fixed to the gear ring (which of course extends from the cover), and a scale provided on the cover (which is stationary), and the weight of the dumbbell displayed by the lever being pulled to the scale position. In the present embodiment, the first cover 147 is used as an operation member of the adjustment mechanism 14, which can save parts, simplify the operation, and make the scale display more clear.

The center of the gear ring support 146 is provided with a through hole which is sleeved on the outer edge of the circular planet wheel support 145, so that the gear ring support 146 can rotate around the planet wheel support 145.

As shown in fig. 3 and 6, the transmission shaft 142 is an elongated shaft, which penetrates through the first weight portion 12 and the second weight portion 14, and has an outer diameter smaller than the diameter of the dumbbell sheet open slot 1222 at the corresponding position of the dumbbell sheet 122. The first driving sleeve 143 and the second driving sleeve 144 are sleeved at two ends of the driving shaft 142, and the driving shaft 142 is engaged with the first driving sleeve 143 and the second driving sleeve 144 so that the driving shaft 142 can drive the first driving sleeve 143 and the second driving sleeve 144 to move. In this embodiment, the transmission shaft 142 is a screw, the first transmission shaft sleeve 143 and the second transmission shaft sleeve 144 are nuts respectively, the two ends of the screw are provided with external threads 1421, the nuts are internally provided with internal threads 1431 (the two internal threads have opposite directions), which are matched with the external threads 1421, and the transmission shaft 142 drives the first transmission shaft sleeve 143 and the second transmission shaft sleeve 144 to move through the matching of the internal threads 1431 and the external threads 1421. In other embodiments, other structures are also possible, so that the transmission shaft drives the first driving sleeve and the second driving sleeve to move, for example, the spiral groove is matched with the convex pin, but the thread matching rotation of the embodiment is smoother.

The outer diameters of the first driving sleeve 143 and the second driving sleeve 144 are larger than the width of the opening groove 1222 and smaller than the diameter of the mounting hole 1221, and the first driving sleeve 143 and the second driving sleeve 144 can axially move (move in opposite directions or move in opposite directions due to opposite directions of the two internal threads) under the driving of the driving shaft 142, so that the first driving sleeve 143 and the second driving sleeve 144 can be inserted into (move in opposite directions) or separated from (move in opposite directions) the mounting holes 1221 of part or all of the dumbbell plates 122 towards both ends, and the number of the dumbbell plates 122 fixed on the first driving sleeve 143 and the second driving sleeve 144 is adjusted, so that the dumbbell plates 122 are left or separated from the first weight portion 12 and the second weight portion 13, thereby adjusting the weight of the dumbbell (a specific adjustment mode will be described later). In this embodiment, the transmission ratios between the gear ring 1411 and the sun gear 1412, and between the transmission shaft 142 and the first and second driving

sleeves

143, 144 are calculated, so that when the gear ring 1411 rotates for one turn, the first and second driving

sleeves

143, 144 axially move by five times the center distance between two adjacent dumbbell plates (which may be other multiples, which corresponds to the number of dumbbell plates, where the multiple is equal to the number of dumbbell plates on one side plus 1 in this embodiment). In other embodiments, not limited to one turn corresponding to the number of dumbbell pieces, other correspondences may be provided, such as half a turn or 2/3 turns, and the first and

second sleeves

143, 144 may be axially displaced by five times the center distance between two adjacent dumbbell pieces. The setting mode of one circle corresponding to the number of the dumbbell pieces is easy to grasp (the intervals between five scales are equal) and convenient (the rotation amplitude is large).

In order to prevent the first driving sleeve 143 and the second driving sleeve 144 from rotating together with the driving shaft 142, the first driving sleeve 143 and the second driving sleeve 144 are further provided with a rotation stopping structure, so that the first driving sleeve 143 and the second driving sleeve 144 axially move under the driving of the driving shaft 142 due to the limitation of the rotation stopping structure. In this embodiment, the rotation stopping structure includes

rotation stopping pins

1432 and 1442 provided on the outer peripheries of the first driving sleeve 143 and the second driving sleeve 143. The rotation of the first and

second bosses

143, 144 with the shaft 142 is restricted by the engagement of the rotation-stopping grooves 111 on the handle 11 with the rotation-stopping

pins

1432, 1442. The transmission shaft 142 is further provided with an annular groove 1422 at a middle position, the handle 11 is provided with a semicircular limiting member 113 at a corresponding position, the semicircular limiting member 113 is fixed to the main body of the handle through the handle screw 112, and the transmission shaft 142 is arranged in the semicircular limiting member 113 through the annular groove 1422, so that the transmission shaft 142 can rotate relative to the handle 11 but cannot move axially.

As shown in fig. 3 and 4, the prompting mechanism includes a fixing member (in this embodiment, the second outer blocking plate 1312 of the second dumbbell plate holder 131 is used as the fixing member), an elastic member 151 (in this embodiment, a spring), a ball 152, and a rotating member 153. The rotating member 153 is fixed to the transmission shaft 142 and can rotate along with the transmission shaft 142. The rotating member 153 is a circular plate having a plurality of teeth slots 1532 uniformly distributed around the circumference thereof. The rotating member 153 has a plurality of circular holes 1531 (five in this embodiment), and the center of the circle formed by the circular holes 1531 is located at the axis of the transmission shaft 142. The sleeve 154 is fixed on the fixing member 1312 corresponding to the circular hole 1531, and the ball 152 is mounted on the outer end of the sleeve 154, so that the ball 152 can be movably fixed on the fixing member 1312. The elastic element 151 is located between the ball 152 and the fixing element 1312, and presses the ball 152 to the end of the sleeve 154, pushing the ball 152 to move outward. The sleeve 154 corresponds to the rotation path of the circular hole 1531, and the balls 152 are located on a circle formed by the center of the circular hole 1531 (i.e., on the rotation path of the circular hole 1531). The ball 152 and the circular hole 1531 are properly positioned, so that when the dumbbell is adjusted to a predetermined weight, the ball 152 is just in one of the circular holes 1531, and is pushed by the elastic element 151 to fall into the circular hole 1531, and collides with the rotating element 153 to generate sound, so as to prompt a user.

The self-locking mechanism further includes a locking member 161, a resilient member 162 (in this embodiment, a torsion spring), and a mounting member 163. The locking member 161 includes an upper blocking portion 1611 and a lower blocking portion 1612 (as shown in fig. 5). The locking member 161 is rotatably fixed to the fixing member 1312 by a mounting member 163 (in this embodiment, a pin and a locking ring, although other fixing structures may be adopted), the resilient member 162 is located between the locking member 161 and the fixing member 1312, and the locking member 161 and the resilient member 162 are connected to each other, so that the resilient member 162 can drive the upper stopping portion 1611 to rotate inwards and (in a free state) be locked into the tooth socket 1532. At this time, the rotating member 153 is locked and cannot rotate, and the transmission shaft 142 and the first cover 147 cannot rotate, so that it is ensured that the first cover 147 cannot rotate due to misoperation in the using process of the dumbbell, and the operation safety is ensured. When the handle 11 is placed on the base 3, the lower abutting portion 1612 is abutted by the base 3 (via the protruding piece 33 provided on the base 3, as shown in fig. 2) and drives the upper blocking portion 1611 to rotate outwards, so that the upper blocking portion 1611 is separated from the tooth space 1532, and then the rotating member 153 is released to rotate, and the transmission shaft 142 and the first cover 147 can also rotate, thereby performing the weight adjustment operation.

The outside of the prompting mechanism is also provided with a second cover 158 which covers the periphery of the prompting mechanism and the above parts of the self-locking mechanism to protect the parts.

As shown in fig. 2, one end of the base 3 corresponding to the planetary gear transmission mechanism 141 is provided with a first abdicating groove 31 for accommodating the planetary gear transmission mechanism 141, so as to abdicate and facilitate operation; the other end is provided with a second abdicating groove 32 corresponding to the prompting mechanism for accommodating the prompting mechanism and used for abdicating.

How to adjust the weight is explained below. When the first driving sleeve 143 and the second driving sleeve 144 are located at the innermost positions, the handle portion 1 is lifted, the dumbbell piece 122 is completely left on the base 2, the weight of the dumbbell is 5 pounds, and the 5-pound scale on the first cover 147 is located at the uppermost end. When 10 pounds are required to be added, the first cover body 147 is rotated to a 10-pound position (that is, the 10-pound scale is located at the uppermost end), at this time, the first cover body 147 drives the gear ring 1411 to rotate, the gear ring 1411 drives the transmission shaft 142 to rotate, the transmission shaft 142 drives the first transmission shaft sleeve 143 and the second transmission shaft sleeve 144 to move in opposite directions, and the first transmission shaft sleeve 143 and the second transmission shaft sleeve 144 respectively move outwards by a preset distance (the preset distance is the distance between the centers of two adjacent dumbbell pieces), and at this time, the first transmission shaft sleeve 143 and the second transmission shaft sleeve 144 are located at the centers of the two innermost dumbbell pieces 122. When the rotation is in place, at least one of the balls 152 in the reminder mechanism just falls into the hole 1531 to produce a sound. When the handle portion 1 is lifted, the innermost two dumbbell plates 122 are fixed to the handle portion 1, while the other dumbbell plates 122 remain on the base 3. Other weight adjustments are the same and will not be described in detail. The above-described weight-increasing steps are performed by rotating the first cover 147 in a reverse direction if weight reduction is desired, and moving the first and

second sleeves

143, 144 toward each other, thereby moving the first and

second sleeves

143, 144 inwardly, respectively, away from the center of the dumbbell sheet 122, allowing the dumbbell sheet 122 to remain in the base 3 when the handle portion 1 is lifted.

Compared with the prior art, the dumbbell with adjustable weight of this embodiment locates the first counter weight portion outside through rotary mechanism, utilizes the transmission shaft and the cooperation of first driving sleeve, second driving sleeve to realize the weight of dumbbell and adjusts, and it is very convenient to operate, can bring splendid use for the user and experience. In addition, the planetary gear transmission mechanism is adopted as the rotating mechanism, the weight adjusting operation is labor-saving, and the use experience of a user can be further improved.

In this document, the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for the purpose of clarity and convenience of description of the technical solutions, and thus, should not be construed as limiting the present invention.

As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. The weight-adjustable dumbbell is characterized by comprising a handle part, wherein the handle part comprises a handle, and a first weight portion and a second weight portion which are respectively arranged at two ends of the handle, the first weight portion and the second weight portion respectively comprise a plurality of dumbbell pieces, each dumbbell piece comprises a mounting hole in the middle and an open slot which extends outwards from the mounting hole and penetrates to the outside, and the width of the open slot is smaller than the diameter of the mounting hole; the weight-adjustable dumbbell further comprises an adjusting mechanism, the adjusting mechanism comprises a rotating mechanism, a transmission shaft, a first transmission shaft sleeve and a second transmission shaft sleeve, the rotating mechanism is arranged on the outer side of the first counterweight part, and the rotating mechanism is fixedly connected with the transmission shaft and used for driving the transmission shaft to rotate; the first transmission shaft sleeve and the second transmission shaft sleeve are sleeved on the transmission shaft, and the transmission shaft is meshed with the first transmission shaft sleeve and the second transmission shaft sleeve to enable the transmission shaft to drive the first transmission shaft sleeve and the second transmission shaft sleeve to move; the outer diameters of the first transmission shaft sleeve and the second transmission shaft sleeve are larger than the width of the opening groove and smaller than the diameter of the mounting hole, and the first transmission shaft sleeve and the second transmission shaft sleeve are also provided with rotation stopping structures, so that the first transmission shaft sleeve and the second transmission shaft sleeve axially move under the driving of the transmission shaft due to the limitation of the rotation stopping structures, and are inserted into or separated from part or all of the mounting holes of the dumbbell pieces towards two ends, and the dumbbell pieces are left or separated from the first counterweight part and the second counterweight part, so that the weight of the dumbbell is adjusted.

2. The weight-adjustable dumbbell of claim 1, wherein the driving shaft is a screw, the first driving bushing and the second driving bushing are respectively a first nut and a second nut, external threads are provided at both ends of the screw, and internal threads matched with the external threads are provided inside the first nut and the second nut.

3. The weight adjustable dumbbell of claim 1, wherein the gear ring rotates one revolution in the adjustment mechanism and the first and second outdrives move axially a multiple of the center-to-center distance between two adjacent dumbbell pieces.

4. The weight-adjustable dumbbell of claim 1, wherein the rotation mechanism comprises a planetary gear transmission mechanism, the planetary gear transmission mechanism comprises a ring gear, a sun gear and a planetary gear, the ring gear is used as an operating end, the sun gear is fixedly connected with the transmission shaft, and the ring gear drives the transmission shaft to rotate through the sun gear.

5. The weight-adjustable dumbbell of claim 4, wherein the adjusting mechanism comprises an operating member fixedly connected with the gear ring, so that the operating member can rotate to drive the gear ring to rotate, and the operating member is provided with a plurality of weight scales for displaying the weight of the dumbbell corresponding to the position of the operating member.

6. The weight-adjustable dumbbell of claim 1, wherein the rotation stopping structure comprises rotation stopping pins disposed at the outer periphery of the first driving bushing and the second driving bushing, the handle is correspondingly provided with rotation stopping grooves, and the rotation of the first driving bushing and the second driving bushing along with the driving shaft is limited by the cooperation of the rotation stopping grooves and the rotation stopping pins.

7. The weight adjustable dumbbell of claim 6, wherein the handle is hollow and the drive shaft is located in the handle for relative rotation but not axial movement.

8. The weight-adjustable dumbbell of claim 1, wherein the weight-adjustable dumbbell is provided with a prompting mechanism outside the second weight portion, the prompting mechanism includes a fixing member, an elastic member, a ball, and a rotating member, the rotating member is fixed to the transmission shaft and can rotate along with the transmission shaft, the rotating member is provided with a plurality of circular holes, the center of a circle formed by the centers of the circular holes is located on the axis of the transmission shaft, the ball is movably fixed to the fixing member, is pressed by the elastic member, and is located on the rotation path of the circular holes, so that when the dumbbell is adjusted to a predetermined weight, the ball is pushed by the elastic member to fall into the circular holes.

9. The weight adjustable dumbbell of claim 8, further comprising a base for placement of the handle portion, the rotating piece is a circular plate with a plurality of tooth sockets uniformly distributed on the periphery, the weight-adjustable dumbbell is provided with a self-locking mechanism on the outer side of the second counterweight part, the self-locking mechanism comprises a locking piece and a rebound piece, the locking piece comprises an upper blocking part and a lower abutting part, the locking piece is rotatably fixed on the fixed piece, the rebound piece is positioned between the locking piece and the fixed piece, the locking piece is connected with the rebound piece, so that the rebound piece can drive the upper blocking part to rotate inwards and be clamped in the tooth socket, and when the handle part is placed on the base, the lower abutting part is abutted by the base and drives the upper blocking part to rotate outwards, so that the upper blocking part is separated from the tooth groove.

10. The weight adjustable dumbbell of claim 8, wherein the first weight portion and the second weight portion each include a dumbbell sheet mount for receiving a dumbbell sheet, the fixture being secured to the dumbbell sheet mount.