Adjustable Dumbbell

Description

TECHNICAL FIELD

The present disclosure relates to the technical field of fitness equipment, particularly to an adjustable dumbbell.

BACKGROUND

A dumbbell is a common strength training equipment, typically consisting of a short bar and weight blocks at both ends, mainly used for muscle strength training, shaping, and functional exercises. Its characteristics include compact size, flexible use, and suitability for single or double-handed gripping.

To allow users to flexibly adjust the weight of the dumbbell, many adjustable dumbbells have appeared on the market, such as a rotary dumbbell disclosed in application number CN2020214260128, which includes a handle portion, weight portions located at both ends of the handle portion, and a transmission self-locking mechanism and a driven mechanism arranged at both ends of the handle portion and respectively abutting against the two weight portions; the transmission self-locking mechanism includes a transmission assembly; the transmission assembly comprises a star-shaped gear transmission mechanism, a first output screw, a long nut fitted with the first output screw, and a first screw spline splined to the first output screw; the long nut is rotationally connected to the star-shaped gear transmission mechanism, enabling the long nut to rotate under the drive of the star-shaped gear transmission mechanism, causing the first output screw to move axially through the first screw spline.

The above technical solution, through the design of a star-shaped gear adjustment mechanism, achieves the function of rotary automatic addition and subtraction of dumbbell plates. Compared with traditional dumbbells, while it significantly improves the convenience of dumbbell use, the planetary gear adjustment mechanism is relatively complex, not only resulting in higher production costs but also making it difficult to repair or replace in case of wear, leaving room for improvement.

SUMMARY

The present disclosure provides an adjustable dumbbell to solve the problems raised in the background art.

To achieve the above object, the present disclosure adopts the following technical solutions:

An adjustable dumbbell comprises a dumbbell bar internally provided with an axially extending guide rail; connection seats arranged at both ends of the dumbbell bar, each provided with a mounting hole at a center thereof; a weight assembly comprising a plurality of stacked weight units, wherein each weight unit is provided with a through hole, and a detachable lateral interlocking structure is arranged between adjacent weight units to restrict a horizontal relative displacement between the adjacent weight units; a spindle laterally slidably arranged inside the dumbbell bar and extending into the mounting holes of the connection seats, wherein an outer surface of the spindle is provided with a helical groove and an axially extending guide groove; and a spline arranged inside the connection seat, wherein the spline is provided with a boss extending into the helical groove, and the boss presents a helical shape matching the helical groove. The guide rail inside the dumbbell bar is slidably fitted with the guide groove of the spindle to directly transmit a rotational motion of the dumbbell bar to the spindle, thereby achieving synchronous rotation of the dumbbell bar and the spindle. When the spindle is rotated, the boss slides along the helical groove, converting a rotational motion of the spindle into an axial movement. When the spindle is extended axially, a tail end thereof penetrates the connection seats and the through hole of at least one weight unit, forming a longitudinal constraint on the weight unit, allowing the weight assembly to be fixedly connected to the connection seats. When the spindle is retracted axially, the tail end thereof withdraws from the through hole, releasing the longitudinal constraint, allowing the weight assembly to be separated from the connection seats.

Another technical solution provided by the present disclosure: an adjustable dumbbell comprises a dumbbell bar; connection seats arranged at both ends of the dumbbell bar, each provided with a mounting hole at a center thereof; a weight assembly comprising a plurality of stacked weight units, wherein each weight unit is provided with a through hole, and a detachable lateral interlocking structure is arranged between adjacent weight units to restrict a horizontal relative displacement between the adjacent weight units; a spindle laterally slidably arranged inside the dumbbell bar and extending into the mounting holes of the connection seats, wherein an outer surface of the spindle is provided with a helical groove; a spline arranged inside the connection seat, wherein the spline is provided with a boss extending into the helical groove, and the boss presents a helical shape matching the helical groove; and a rotational transmission assembly that is arranged between the dumbbell bar and the spindle and is configured to transmit a rotational motion of the dumbbell bar to the spindle, achieving synchronous rotation of the dumbbell bar and the spindle while allowing the spindle to slide axially relative to the dumbbell bar. When the spindle is rotated, the boss slides along the helical groove, converting the rotational motion of the spindle into axial movement. When the spindle is extended axially, a tail end thereof penetrates the connection seats and the through hole of at least one weight unit, forming a longitudinal constraint on the weight unit, allowing the weight assembly to be fixedly connected to the connection seats. When the spindle is retracted axially, the tail end thereof withdraws from the through hole, releasing the longitudinal constraint, allowing the weight assembly to be separated from the connection seats.

Another technical solution provided by the present disclosure: an adjustable dumbbell comprises a dumbbell bar; connection seats arranged at both ends of the dumbbell bar, each provided with a mounting hole at a center thereof; a weight assembly comprising a plurality of stacked weight units, wherein each weight unit is provided with a through hole, and a detachable lateral interlocking structure is arranged between adjacent weight units to restrict a horizontal relative displacement between the adjacent weight units; a spindle laterally slidably arranged inside the dumbbell bar and extending into the mounting holes of the connection seats; a rotational transmission assembly that is arranged between the dumbbell bar and the spindle and is configured to transmit a rotational motion of the dumbbell bar to the spindle, achieving synchronous rotation of the dumbbell bar and the spindle while allowing the spindle to slide axially relative to the dumbbell bar; and an axial conversion assembly that is arranged between the spindle and the connection seat and converts a rotational motion of the spindle into an axial movement of the spindle when the spindle is rotated. When the spindle is extended axially, a tail end thereof penetrates the connection seats and the through hole of at least one weight unit, forming a longitudinal constraint on the weight unit, allowing the weight assembly to be fixedly connected to the connection seats. When the spindle is retracted axially, the tail end thereof withdraws from the through hole, releasing the longitudinal constraint, allowing the weight assembly to be separated from the connection seats.

The beneficial effects of the present disclosure over the prior art are: by providing the helical groove and guide groove on the spindle, the guide rail in the dumbbell bar that match the guide groove, and the boss on the spline that extends into the helical grooves, the spindle is rotated synchronously with the dumbbell bar when turned, allowing the boss to slide within the helical groove and extend into or retract from one or more through holes to add or remove weight plates. The structure is relatively simple, with fewer components and easier processing, helping to reduce production and maintenance costs.

BRIEF DESCRIPTION OF DRAWINGS

The drawings, which form part of this application, are included to provide a further understanding of the present disclosure. The illustrative embodiments and the descriptions thereof are intended to explain the present disclosure and do not constitute undue limitations. In the drawings:

FIG. 1 is a perspective view of an embodiment provided by the present disclosure;

FIG. 2 is a schematic structural diagram of the dumbbell bar and connection seat in the embodiment shown in FIG. 1;

FIG. 3 is an exploded view of a single connection seat and dumbbell bar in the embodiment shown in FIG. 2;

FIG. 4 is a schematic structural diagram of the dumbbell bar in the embodiment shown in FIG. 2;

FIG. 5 is a schematic structural diagram of the connection seat in the embodiment shown in FIG. 2;

FIG. 6 is a schematic diagram of the connection between the side plate and washer in the embodiment shown in FIG. 5;

FIG. 7 is an internal cross-sectional view of the side plate and spline connection in the embodiment shown in FIG. 5;

FIG. 8 is a schematic structural diagram of the washer in the embodiment shown in FIG. 6;

FIG. 9 is a schematic structural diagram of the spline in the embodiment shown in FIG. 7;

FIG. 10 is a schematic structural diagram of the cover in the embodiment shown in FIG. 5;

FIG. 11 is a schematic diagram of the connection between the cover, spline, and spindle in the embodiment shown in FIG. 5;

FIG. 12 is a cross-sectional view of the internal structure of the embodiment shown in FIG. 11;

FIG. 13 is a schematic structural diagram of the slider in the embodiment shown in FIG. 11;

FIG. 14 is a schematic structural diagram of the base in the embodiment shown in FIG. 1;

FIG. 15 is a schematic structural diagram of the weight holder in the embodiment shown in FIG. 14;

FIG. 16 is an exploded schematic diagram of a plurality of weight plates in the embodiment shown in FIG. 1;

FIG. 17 is a schematic structural diagram of a single weight plate in the embodiment shown in FIG. 16;

FIG. 18 is another schematic structural diagram of the embodiment shown in FIG. 6.

Reference signs: Base (100); Mounting seat (110); Connecting rod (120); Weight holder (130); Engagement groove (131); Accommodating groove (132); Lug (133); Weight assembly (200); Weight plate (210); Inner plate (211); Intermediate plate (212); Outer plate (213); First embedding groove (214); First embedded block (215); Through hole (220); Dumbbell bar (300); First spindle (310); Helical groove (311); Guide groove (312); Guide rail (320); Outer sleeve (330); Positioning notch (331); Inner sleeve (340); Positioning block (341); Calibration dial (350); Connection seat (400); Mounting hole (410); Spline (420); Boss (421); Positioning groove (422); Side plate (430); First penetrating hole (431); Clamping plate (432); Washer (433); Flange (434); Cover (440); Second penetrating hole (441); Opening (442); Limiting block (443); Accommodating cavity (450); Disc body (460); Arc segment (461); Slider (470); Passage slot (471); Elongated hole (472); Recess (480); Viewing window (481); Second embedding groove (500); Second embedded block (600); Third embedded block (700); Top notch (a); Side notch (b); Inner wall (c).

DESCRIPTION OF EMBODIMENTS

The technical solution in the embodiment of the present disclosure will be clearly and completely described below with reference to the drawings. Obviously, the described embodiment is part of, rather than all of the embodiments of the present disclosure. The following description of at least one exemplary embodiment is illustrative in nature and is in no way intended to limit the present disclosure, its application or uses. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present disclosure.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is also intended to include the plural form unless the context clearly indicates otherwise. Furthermore, it should be appreciated that when the terms “comprising” and/or “including” are used in this specification, they specify the presence of features, steps, operations, devices, components and/or combinations thereof.

Unless otherwise specified, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure. At the same time, it should be appreciated that for the convenience of description, the dimensions of various parts shown in the drawings are not drawn according to the actual scale relationship. Techniques, methods and equipment known to those skilled in the art may not be discussed in detail, but in appropriate cases, they should be regarded as part of the authorization specification. In all the examples shown and discussed herein, any specific values should be interpreted as illustrative, and not as limiting. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters indicate similar items in the following drawings, therefore once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

An adjustable dumbbell includes a base 100, two weight assemblies 200, and a dumbbell bar 300 (refer to FIG. 1).

In this embodiment, referring to FIGS. 14 and 15, the base 100 includes two opposing mounting seats 110. Two symmetrically arranged connecting rods 120 are inserted between the two mounting seats 110, and a weight holder 130 is disposed between the two connecting rods 120. The two weight assemblies 200 are symmetrically placed between the weight holder 130 and the mounting seats 110.

In other embodiments, referring to FIG. 15, the weight holder 130 is provided with engagement grooves 131 on the side facing the two connecting rods 120, and both connecting rods 120 are engaged in the engagement grooves 131.

In other embodiments (not shown), the weight holder 130 may be fixedly installed between the two connecting rods 120.

In other embodiments (not shown), anti-slip pads are fixedly installed at the bottoms of the weight holder 130 and the two mounting seats 110. The anti-slip pads (typically made of rubber, silicone, or other high-friction materials) significantly increase the friction between the base and the contact surface (such as a table or floor). When the weight assembly 200 is placed on the base 100, the anti-slip pads effectively prevent accidental sliding, displacement, or tipping of the base 100.

In other embodiments (not shown), there may be two weight holders 130, with a rotating structure placed between the two weight holders 130, allowing the two weight holders 130 to rotate relative to each other. This facilitates the storage of the base 100. Additionally, when the two weight holders 130 are rotated to an appropriate angle, the two mounting seats 110 form an inverted V-shape, making it convenient to place kettlebells. Thus, the base 100 can accommodate both dumbbells and kettlebells.

In this embodiment, referring to FIGS. 1 and 16, the weight assembly 200 consists of a plurality of weight plates 210. Adjacent weight plates 210 are longitudinally slidably fitted, and a through hole 220 is provided at the center of each weight plate 210.

In other embodiments, referring to FIG. 16, the plurality of weight plates 210 include an inner plate 211, several intermediate plates 212, and an outer plate 213. Both side of the inner plate 211, both side of the intermediate plates 212, and the side of the outer plate 213 facing the intermediate plates 212 are all equipped with first embedding grooves 214 and first embedded blocks 215. Two adjacent weight plates 210 are interconnected through a complementary structure of the first embedding grooves 214 and the first embedded blocks 215.

Here, referring to FIGS. 16 and 17, the diameters of the first embedding groove 214 and the first embedded block 215 at the top of the weight plate 210 is much larger than that those of the first embedding groove 214 and the first embedded block 215 at the bottom. The larger top structure of the weight plate 210 acts like a funnel or guide. When a user inserts a new weight plate 210 onto an existing one, even if the initial alignment is slightly off, the larger top first embedding groove 214 can more easily “capture” and accommodate the larger top first embedded block 215 of another weight plate 210. This significantly increases the fault tolerance during initial contact, allowing the insertion process to begin without requiring extremely precise alignment. This greatly simplifies the assembly (stacking) operation, especially when a plurality of weight plates 210 need to be added quickly, thus enhancing the user experience.

In other embodiments, referring to FIGS. 16 and 17, when a weight plate 210 is placed vertically, the inner wall diameter of the first embedding groove 214 is made larger than the diameter of a side notch, while the shape of the first embedded block 215 matches the first embedding groove 214. When the first embedded block 215 on one weight plate 210 is inserted into the first embedding groove 214 of another weight plate 210 along a top notch, the main body of the first embedded block 215 is confined within the spacious interior of the first embedding groove 214 since the inner wall diameter is larger than the side notch diameter. Since the diameter of the first embedded block 215's main body exceeds that of the side notch, the first embedded block 215 is unlikely to disengage from the side notch, preventing the first embedded block 215 from being disengaged from the first embedding groove 214 along the direction of the side notch. When a plurality of weight plates 210 are stacked horizontally, workers can take up them without worrying about separation of the weight plates due to minor collisions or tilting, reducing the risk of injury or equipment damage. The mechanical interlock between a plurality of weight plates 210 is achieved solely through geometric shapes, eliminating the need for additional parts like bolts or clips, thereby simplifying structure and assembly.

In other embodiments, the weight assembly 200 is not limited to weight plates 210 but may also include one or more weight blocks or weight balls.

In other embodiments, referring to FIG. 14, the side surface of the mounting seat 110 facing the weight holder 130 is fixed with a third embedded block 700. By slidable fitting of the third embedded block 700 with the first embedding groove 214 on the outer plate 213, the weight assembly 200 is more securely placed between the weight holder 130 and the mounting seat 110 without lateral sliding.

In this embodiment, referring to FIGS. 2, 3, and 4, both ends of the dumbbell bar 300 are equipped with connection seats 400 for longitudinal slidable fitting the weight assembly 200. The connection seats 400 have mounting holes 410 coaxial with the through holes 220. The two ends of the dumbbell bar 300 and the two connection seats 400 are in one-to-one correspondence and are rotatably fitted with each other. Inside the dumbbell bar 300, two spindles 310 are arranged laterally and are slidably horizontally fitted with the dumbbell bar 300, and the spindle 310 extends into the mounting hole 410 on the same side.

In other embodiments (not shown), the dumbbell bar 300 is rotationally connected to the connection seat 400 through bearings.

In other embodiments, referring to FIG. 4, the outer surface of the spindle 310 is provided with a helical groove 311, and both the top and bottom are equipped with axially extending guide grooves 312. The dumbbell bar 300 contains guide rails 320 that are slidably fitted with the two guide grooves 312. Referring to FIGS. 3 and 9, the connection seat 400 houses a spline 420 sleeved outside the spindle 310. The center of the spline 420 is provided with a central hole, into which the spindle 310 extends. The inner wall of the central hole is fixedly provided with a boss 421 that extends into the helical groove 311, where the boss 421 adopts a helical shape matching the helical groove 311.

When the dumbbell bar 300 rotates, the boss 421 slides within the helical groove 311, making the spindle 310 extend into one or more through holes 220 or be disengaged from the through holes 220.

Here, the slidable fitting between the guide rails 320 and the guide grooves 312 prevents the spindle 310 from deviating during translation, enhancing stability. Simultaneously, the mutual constraint between the guide rails 320 and the guide grooves 312 ensures that when the dumbbell bar 300 rotates, it drives the spindle 310 to rotate synchronously through the guide rails 320 and guide grooves 312.

In this embodiment, referring to FIG. 4, the dumbbell bar 300 includes an outer sleeve 330 and two inner sleeves 340 within the outer sleeve 330. The two inner sleeves 340 are arranged left and right, each corresponding to one of the two spindles 310 and sleeved over the outer surfaces of the corresponding spindles 310. Both guide rails 320 are fixed to either the top wall or bottom wall of the inner sleeves 340.

In other embodiments, referring to FIG. 4, both ends of the outer sleeve 330 are equipped with positioning notches 331, while the inner sleeves 340 are fixedly provided with positioning blocks 341 fitted with the corresponding positioning notches 331. By providing the positioning notches 331 and positioning blocks 341, after the inner sleeves 340 are inserted into the outer sleeve 330 and the positioning blocks 341 are engaged and fitted with the positioning notches 331, the user can rotate the outer sleeve 330 to synchronously rotate the inner sleeves 340, making assembly more convenient.

In this embodiment, referring to FIGS. 3, 5, 6, and 10, the connection seat 400 includes a side plate 430 with a first penetrating hole 431 and a cover 440 with a second penetrating hole 441. One side of the side plate 430 is slidably connected to the weight assembly 200, while the cover 440 is placed on the other side of the side plate 430 and is fitted with the side plate 430 to form an accommodating cavity 450. The mounting hole 410 is formed by the fitting of the first penetrating hole 431 and the second penetrating hole 441. Referring to FIGS. 7 and 11, the end of the dumbbell bar 300 passes through the second penetrating hole 441 and extends into the accommodating cavity 450, with the spline 420 positioned at the first penetrating hole 431.

When the spindle 310 moves, the entire motion occurs within the accommodating cavity 450, preventing accidental collisions with external objects and ensuring continuous, stable operation.

In other embodiments, referring to FIGS. 6 and 7, the side plate 430 is fixed with two clamping plates 432 symmetrically arranged around the first penetrating hole 431 on the side facing the spline 420. A clamping groove matching the spline 420 is formed between the two clamping plates 432 and the first penetrating hole 431, allowing the spline 420 to be engaged and fitted with the clamping groove.

Here, the cross-section of the clamping groove is non-circular, matching the outer profile of the spline 420. The spline 420 can be assembled by snapping the spline 420 into the clamping groove without relative rotation of the spline 420.

In other embodiments, referring to FIGS. 7, 8, and 9, one side of the spline 420 features a positioning groove 422. A washer 433 is installed inside the first penetrating hole 431, with one side of the washer 433 extending into the clamping groove and extending radially outward to form a flange 434. The flange 434 abuts against the groove bottom of the positioning groove 422, while the inner diameter of the washer 433 matches that of the spline 420.

Here, the flange 434 is clamped between the side plate 430 and the spline 420, serving as a stopper to ensure the spline 420 remains firmly fixed in its designed axial position without displacement due to vibration, load, or operation.

In this embodiment, referring to FIGS. 11 and 12, the outer side of the dumbbell bar 300 is fixed with a disc body 460 that is rotatably fitted with the accommodating cavity 450. One side of the disc body 460 is fixed with a plurality of arc segments 461 distributed circumferentially, with gaps between adjacent arc segments 461.

In other embodiments, referring to FIG. 10, the lower side of the cover 440 has an opening 442. Referring to FIG. 11, a slider 470 capable of sliding vertically is arranged inside the accommodating cavity 450. Referring to FIGS. 11 and 13, the side of the slider 470 facing the disc body 460 is provided with a passage slot 471, which runs through the front and rear sides of the slider 470.

In other embodiments, referring to FIG. 15, the weight holder 130 is provided with accommodating grooves 132 on both sides facing the two mounting seats 110. The diameter of the accommodating grooves 132 is the same as that of the connection seat 400, allowing the connection seat 400 to be placed inside the accommodating grooves 132. The bottom wall of each accommodating groove 132 is equipped with two lugs 133, which correspond one-to-one with the two openings 442.

When the connection seat 400 is placed on the weight holder 130, the lugs 133 pass through the corresponding openings 442 and push the slider 470, aligning the passage slot 471 with the arc segment 461 on the same curve. At this point, there is no interference between the disc body 460 and the slider 470, meaning the disc body 460 is unlocked, allowing the dumbbell bar 300 to be rotated to adjust the position of the spindle 310. When the connection seat 400 is separated from the weight holder 130, the slider 470 slides downward, causing the passage slot 471 to misalign with the arc segment 461. The side of the slider 470 then lies along the extension direction of the arc segment 461, creating interference between the disc body 460 and the slider 470. The disc body 460 is locked by the slider 470, and the dumbbell bar 300 cannot be rotated to adjust the spindle 310's position. Through this structural design, when the dumbbell is placed on the base 100, the dumbbell bar 300 can be rotated to adjust the spindle 310's position for adding or removing weight plates 210. When the dumbbell is removed from the base 100, the disc body 460 is locked by the slider 470, preventing the dumbbell bar 300 from rotating autonomously and avoiding accidental detachment of the weight plates 210 during training, ensuring safe and worry-free use.

In other embodiments, referring to FIGS. 11 and 13, the slider 470 is equipped with an elongated hole 472, while the cover 440 features a sliding groove and a limiting block 443 within the sliding groove. The slider 470 is slidably fitted with the sliding groove, and the limiting block 443 extends into the elongated hole 472, thereby restricting the slider 470 to linear movement along the sliding groove's direction.

In this embodiment, please refer to FIGS. 11 and 18. The side plate 430 is provided with two hollow cylinders symmetrically arranged around the first penetrating hole 431 on the side facing the cover 440. Each cylinder contains a spring-loaded ball and an elastic component connected to it. The disc body 460 has a plurality of positioning holes on its corresponding circumferential surface, with diameters smaller than that of the spring-loaded ball. When the disc body 460 is rotated, the positioning holes misalign with the cylinders, causing the disc body 460 to press the spring-loaded balls, retracting them into the cylinders. During this process, the elastic component is compressed to store energy. Once the disc body 460 rotates to the next position, the spring-loaded balls quickly snap into the new positioning holes under the spring force, producing a distinct “click” sound. This sound provides clear feedback to the user for weight position switching.

In other embodiments, the elastic component may be a spring or an elastic pad.

In this implementation, please refer to FIG. 2. The connection seat 400 is provided with a recess 480 on the side facing the dumbbell bar 300, and the inner bottom wall of the recess 480 has a viewing window 481 connected to the accommodating cavity 450. Please refer to FIG. 12. A calibration dial 350 is fixed on the outer side of the dumbbell bar 300 within the accommodating cavity 450, with the outer sidewall of the calibration dial 350 positioned directly below the viewing window 481. The outer circumference of the calibration dial 350 is marked with a plurality of weight gradations, each displaying a different numerical value.

When the user adds or removes weight plates 210, the rotation of the dumbbell bar 300 drives the calibration dial 350 to rotate, causing the weight gradations displayed in the viewing window 481 to change. This allows the user to observe the variation in weight gradations through the viewing window 481, providing an intuitive confirmation of the current weight setting.

In this embodiment, please refer to FIG. 5. A second embedding groove 500 and a second embedded block 600 are arranged on the surface of the connection seat 400 on a side away from opposite the dumbbell bar 300. The first embedding groove 214 on the side of the inner plate 211 away from the intermediate plate 212 is used for fitting with the second embedded block 600, while the first embedded block 215 on the same side of the inner plate 211 is used for fitting with the second embedding groove 500.

It should be noted that a plurality of weight plates 210 are prevented from lateral movement between adjacent weight plates 210 through the fitting of embedding grooves and embedded blocks. Simultaneously, the spindle 310 passes through the through hole 220 to prevent longitudinal movement of the corresponding weight plate 210, thereby locking the weight plate 210. Additionally, by providing a second embedding groove 500 and a second embedded block 600 on the connection seat 400, a lock is formed between the connection seat 400 and the weight plate 210 when the spindle 310 passes through the through hole 220. When the spindle 310 is disengaged from the through hole 220, the user can lift the dumbbell bar 300 to separate the connection seat 400 from the weight plate 210.

In summary, as can be seen from the above description, the present disclosure achieves the following technical effects: by providing a helical groove 311 and a guide groove 312 on the spindle 310, a guide rail 320 matching the guide groove 312 inside the dumbbell bar 300, and a boss 421 on the spline 420 extending into the helical groove 311, the spindle 310 and the dumbbell bar 300 rotate synchronously when the dumbbell bar 300 is rotated; the boss 421 can slide within the helical groove 311, causing the spindle 310 to extend into one or more through holes 220 or disengage from the through hole 220, thereby adding or removing weight plates 210; the structure is relatively simple, with fewer components and ease of processing, which helps reduce production and maintenance costs.

In the description of the present disclosure, it should be appreciated that directional terms such as “front, rear, up, down, left, right”, “horizontal, vertical, perpendicular, horizontal” and “top, bottom” etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description. In the absence of a contrary explanation, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present disclosure; the directional terms “inside, outside” refer to the inside and outside relative to the contour of each component itself.

For the convenience of description, spatial relative terms such as “on . . . ”, “above . . . ”, “on the upper surface of . . . ”, “upper” etc. may be used here to describe the spatial positional relationship of a device or feature with other devices or features as shown in the drawings. It should be appreciated that spatial relative terms are intended to encompass different orientations of the device in use or operation other than the orientation described in the drawings. For example, if the device in the drawing is inverted, the device described as “above other devices or structures” or “on other devices or structures” will subsequently be positioned as “below other devices or structures” or “under other devices or structures”. Thus, the exemplary term “above” can include both “above” and “below” orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here should be interpreted accordingly.

In addition, it should be noted that the use of terms such as “first”, “second” etc. to define components is for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning, and therefore should not be understood as limiting the scope of protection of the present disclosure.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure can have various modifications and changes. Any modifications, equivalent replacements, improvements etc. made within the spirit and principles of the present disclosure should be included within the scope of protection of the present disclosure.