Dumbbell with balance weight convenient to adjust
By designing handles, dumbbell racks, support rods, counterweight blocks and adjustment mechanisms in dumbbells, the existing dumbbell adjustment counterweight operation problem is solved, and a simple and easy-to-operate counterweight adjustment method is realized, which improves the convenience of use.
Patent Information
- Application Number
- CN202421316636.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-11
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-06-11
AI Technical Summary
Existing dumbbells are troublesome to operate when adjusting the counterweight and are inconvenient to use.
A dumbbell including a handle, a dumbbell rack, a support rod, a counterweight and an adjustment mechanism are designed. By providing a support rod on the dumbbell rack and an opening slot and a hook groove on the counterweight block, the support rod is slid to slide into or out of the hook groove of the counterweight block by using the adjustment mechanism, thereby achieving simple and easy-to-operate counterweight adjustment.
The fast, simple and easy-to-operate adjustment method of dumbbell counterweight is realized, and the tedious process of manual assembly and tightening of bolts in the prior art is avoided, and the convenience of use is improved.
Smart Images
Figure CN222942871U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of fitness equipment, and in particular relates to a dumbbell with easy-to-adjust counterweight. Background Art
[0002] Dumbbells are an auxiliary equipment for weightlifting and fitness exercises, which can be used to enhance muscle strength training. At present, dumbbells are often equipped in gyms or in the homes of fitness enthusiasts. Existing dumbbells generally include a dumbbell bar and a plurality of weight blocks. When adjusting the weight, the weight blocks need to be manually assembled to the two ends of the dumbbell bar one by one to adjust the weight, and then the ends of the dumbbell bar need to be tightened by bolts. This adjustment method is very inconvenient. Utility Model Content
[0003] The utility model provides a dumbbell with easy-to-adjust counterweight, aiming to solve the problem that the dumbbell in the prior art is troublesome and inconvenient to operate when adjusting the counterweight.
[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is:
[0005] A dumbbell with easy-to-adjust weight comprises a handle and at least one dumbbell assembly connected to the handle; the dumbbell assembly comprises:
[0006] A dumbbell rack with a weight base;
[0007] A support rod is slidably disposed on the dumbbell rack and the sliding direction is perpendicular to the axis of the dumbbell rack;
[0008] A plurality of counterweight blocks are arranged in parallel along the axial direction of the dumbbell rack, each of the counterweight blocks is provided with an opening groove which is opened upward and is used for splicing on the outer side of the counterweight block base, and a hanging groove is provided in the opening groove for hanging the counterweight block on the support rod; and,
[0009] The adjusting mechanism is arranged on the dumbbell rack, and the adjusting mechanism drives the supporting rod to slide back and forth along the dumbbell rack so that the supporting rod slides into or out of the hanging groove of the counterweight block.
[0010] A further solution: the adjustment mechanism includes a rotating shaft rotatably arranged on the dumbbell rack and connected to the handle, an eccentric wheel sleeved on the rotating shaft, and a reset member, a plurality of tooth grooves cooperating with the support rod are arranged around the eccentric wheel, when the rotating shaft is driven to rotate by the handle and the rotating shaft drives the eccentric wheel to rotate, the support rod abuts against different tooth grooves under the rotation of the eccentric wheel, so that the support rod slides into or out of the hanging grooves of different counterweight blocks;
[0011] The reset member is arranged between the support rod and the dumbbell rack and is used to make the support rod abut against the tooth groove.
[0012] Based on the above technical solution: by setting a rotating shaft, an eccentric wheel and a reset member, and setting a plurality of tooth grooves around the eccentric wheel, when the user adjusts the weight of the dumbbell, the handle can be turned to drive the rotating shaft to rotate and then drive the eccentric wheel to rotate. When the eccentric wheel rotates, different tooth grooves abut against the support rod, so that the support rod slides into or out of the hanging grooves on different counterweight blocks, so that the counterweight blocks can be assembled on the dumbbell rack or removed, and the adjustment method is simple and easy to operate. The reset member is used to keep the support rod against the tooth groove, so that the support rod and the tooth groove always keep abutting against each other, which is safer.
[0013] A further solution: the reset member is an elastic reset member, the dumbbell rack is provided with a guide groove, the support rod is provided with a pin inserted in the guide groove, and the elastic reset member is located between the bottom wall of the guide groove and the pin.
[0014] Based on the above technical solution: the pin is inserted into the guide groove to prevent the support rod from deviating when the support rod slides along the dumbbell rack. The elastic reset member is arranged between the bottom wall of the guide groove and the pin, which facilitates a more reasonable installation structure layout.
[0015] A further solution: there are two latches, which are respectively located at two ends of the support rod, and there are two guide grooves and two elastic reset members, which correspond to the two latches one by one.
[0016] Based on the above technical solution: the above arrangement enables the forces at both ends of the support rod to be balanced, so that the support rod can smoothly slide into or out of the hanging groove during adjustment.
[0017] A further solution is that there are two eccentric wheels, which are respectively against two ends close to the support rod.
[0018] Based on the above technical solution: two eccentric wheels are provided and are respectively located at the two ends of the support rod, so that when the support rod is driven to slide, the forces at both ends of the support rod are balanced, thereby enabling the support rod to slide smoothly into or out of the hanging groove.
[0019] A further solution: the tooth groove is an arc-shaped groove, and abutment ends are provided near the two ends of the support rod, and the two abutment ends respectively abut against the arc-shaped grooves on the two eccentric wheels.
[0020] A further solution is that a stopper is provided on the outer side of each abutting end, and the two eccentric wheels are located between the two stoppers.
[0021] Based on the above technical solution: by arranging two eccentric wheels between the two blocks, it is possible to avoid the support rod from deviating in a direction parallel to the axis of the dumbbell rack when sliding, so that the support rod can stably cooperate with the two eccentric wheels.
[0022] A further solution: the dumbbell rack is provided with a locking mechanism for locking the rotating shaft and the dumbbell rack.
[0023] Based on the above technical solution: after the user lifts the dumbbell rack upwards by the handle, the locking mechanism locks the rotating shaft and the dumbbell rack to prevent the rotating shaft from rotating relative to the dumbbell rack and causing the counterweight to fall, which is safer during use.
[0024] A further solution is that the dumbbell components have two groups and are symmetrically arranged on the left and right sides of the handle.
[0025] Based on the above technical solution: two sets of dumbbell assemblies are symmetrically arranged on the left and right sides of the handle, so that when adjusting, the counterweight blocks at corresponding positions on the left and right sides are simultaneously assembled on the dumbbells or removed at the same time, so that the weight on the left and right sides is balanced.
[0026] A further solution: the hanging grooves of all the counterweight blocks are located on the same side of the rotating shaft.
[0027] A further solution: the opening groove is a U-shaped groove, the hanging groove is located on a side wall of the U-shaped groove, and in the U-shaped grooves of at least two counterweight blocks, a side wall with hanging grooves is distributed in a stepped manner from the first block to the last block.
[0028] Based on the above technical solution: the hanging groove is set on one side wall of the U-shaped groove, and the one side wall with the hanging groove is distributed in a stepped manner from the first block to the tail block. When adjusting the counterweight, it is convenient for the support rod to slide into or out of different hanging grooves, and more weight gears can be selected.
[0029] A further solution: in the U-shaped grooves of all the counterweight blocks, the distance between one side wall provided with the hanging groove and the other side wall gradually increases in a step-like manner from the side close to the handle to the side far from the handle, and the diameter of the counterweight block base gradually increases in a step-like manner from the side close to the handle to the side far from the handle;
[0030] Alternatively, in the U-shaped grooves of all the counterweight blocks, the distance between one side wall with the hanging groove and the other side wall gradually approaches in a step-like manner from the side close to the handle to the side far from the handle, and the diameter of the counterweight block base gradually decreases in a step-like manner from the side close to the handle to the side far from the handle.
[0031] Based on the above technical solution: when assembling the counterweight, the counterweight can be assembled in sequence from the side close to the handle to the side far from the handle, which is more convenient during adjustment.
[0032] The beneficial effects of the utility model are:
[0033] The utility model provides a support rod on the dumbbell rack, and the sliding direction of the support rod is perpendicular to the axis of the dumbbell rack, and an opening groove with an opening facing upward is provided on each counterweight block, and a hanging groove is provided in the opening groove, so that when installing or removing the counterweight block, the dumbbell rack can be moved from top to bottom to allow the counterweight block base to enter the opening groove, and the adjustment mechanism can drive the support rod to slide along the dumbbell rack, thereby sliding into or out of the hanging groove of the counterweight block. When the support rod slides into the hanging groove of a counterweight block, the counterweight block can be lifted up and assembled on the dumbbell rack, and when the support rod slides out of the hanging groove of a counterweight block, the dumbbell rack can be lifted up to remove the counterweight block, so that the adjustment method of adding or reducing the counterweight block is simple and easy to operate.
[0034] By arranging a counterweight base on the dumbbell rack and splicing the opening groove on the counterweight to the outside of the counterweight base, the gap between the counterweight and the counterweight base is made smaller, which can prevent the counterweight from shaking on the dumbbell rack.
[0035] The hanging groove is arranged in the opening groove, so that after the support rod slides out of the hanging groove, it can pass upward through the opening groove and detach from the counterweight block. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0037] Figure 1 The utility model is a structural schematic diagram of a dumbbell with convenient weight adjustment.
[0038] Figure 2 The utility model is an exploded structural schematic diagram of a counterweight block base and a dumbbell rack.
[0039] Figure 3 The utility model is a schematic diagram of the cross-sectional structure of a dumbbell which is convenient for adjusting the counterweight.
[0040] Figure 4 The utility model is a schematic diagram of the structure of the elastic reset member, the latch and the guide groove matching each other.
[0041] Figure 5 It is a schematic structural diagram of the matching support rod and the hanging groove of the utility model.
[0042] Figure 6 It is a structural schematic diagram of the tooth groove and the support rod abutting against each other in the utility model.
[0043] Figure 7 It is a structural schematic diagram of all the U-shaped grooves of the utility model, in which one side wall provided with the hanging grooves is distributed in a stepped manner.
[0044] Description of the numbers in the figure:
[0045] 1-dumbbell rack; 11-weight block base; 111-bit; 12-slide slot; 13-guide slot; 131-elastic reset member; 14-rotating shaft; 2-handle; 3-weight block; 31-opening slot; 32-hanging slot; 4-eccentric wheel; 41-tooth slot; 5-support rod; 51-rest end; 52-stop block; 53-latch pin; 6-dial. DETAILED DESCRIPTION
[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the utility model.
[0047] like Figures 1 to 7 As shown, this embodiment provides a dumbbell that is easy to adjust the weight, including a handle 2 and at least one group of dumbbell components connected to the handle 2; the dumbbell components include:
[0048] The dumbbell rack 1 is provided with a weight block base 11;
[0049] The support rod 5 is slidably arranged on the dumbbell rack 1 and the sliding direction is perpendicular to the axis of the dumbbell rack 1; the dumbbell rack 1 is provided with a slide groove 12 matched with the support rod 5, and the support rod 5 is arranged in the slide groove 12;
[0050] A plurality of counterweight blocks 3 are arranged in parallel along the axial direction of the dumbbell rack 1, each of the counterweight blocks 3 is provided with an opening groove 31 which is opened upward and is used for splicing on the outside of the counterweight block base 11, and a hanging groove 32 is provided in the opening groove 31 for hanging the counterweight block 3 on the support rod 5; and,
[0051] The adjusting mechanism is arranged on the dumbbell rack 1 , and the adjusting mechanism drives the supporting rod 5 to slide back and forth along the dumbbell rack 1 so that the supporting rod 5 slides into or out of the hanging groove 32 of the counterweight 3 .
[0052] In this embodiment, in order to make the dumbbell more balanced, two groups of dumbbell components are provided, and they are symmetrically arranged on the left and right sides of the handle 2. When adjusting, the counterweights 3 at corresponding positions on the left and right sides will be assembled on the dumbbell or removed at the same time, so that the weight on the left and right sides is balanced.
[0053] As a preferred method, a plurality of counterweights 3 are placed on the counterweight 3 placement seat and the openings of the opening slots 31 are uniformly facing upwards. When adjusting the addition and subtraction of the counterweights 3, when the support rod 5 slides into the hanging slot 32 of a counterweight 3, the counterweight 3 is assembled on the dumbbell rack 1, and its opening slot 31 is spliced on the outside of the counterweight base 11. Since the support rod 5 is located in the hanging slot 32 of the counterweight 3, the counterweight 3 can be lifted by lifting the dumbbell rack 1 upwards. When the support rod 5 slides out of the hanging slot 32 of a counterweight 3, the counterweight 3 is separated from the dumbbell rack 1, and the dumbbell rack 1 is lifted upwards, and the counterweight 3 will remain on the counterweight 3 placement seat.
[0054] Among them, Figure 2 As shown, a plurality of latching positions 111 are provided on the counterweight base 11 , and stoppers are provided between adjacent latching positions 111 , so that the counterweight 3 can be prevented from moving left and right after being assembled on the corresponding latching positions 111 .
[0055] In this embodiment, Figures 2 to 5 As shown, as a specific implementation of the adjustment structure, the adjustment mechanism includes a rotating shaft 14 rotatably arranged on the dumbbell rack 1 and connected to the handle 2, an eccentric wheel 4 sleeved on the rotating shaft 14, and a reset member, and a plurality of tooth grooves 41 cooperating with the support rod 5 are arranged around the eccentric wheel 4. When the rotating shaft 14 is driven to rotate by the handle 2 and the rotating shaft 14 drives the eccentric wheel 4 to rotate, the support rod 5 is abutted against different tooth grooves 41 under the rotation of the eccentric wheel 4, so that the support rod 5 slides into or out of the hanging grooves 32 of different counterweight blocks 3;
[0056] The reset member is arranged between the support rod 5 and the dumbbell rack 1 and is used to make the support rod 5 abut against the tooth groove 41. Specifically, the rotating shaft 14 can be arranged to be a flat square with a non-circular longitudinal section, and a through hole adapted thereto is arranged in the handle 2 so that when the handle 2 is turned, the rotation can be synchronously rotated. The eccentric wheel 4 is sleeved on the rotating shaft 14 and rotates synchronously with the rotating shaft 14, and the rotating shaft 14 is arranged to rotate relative to the dumbbell rack 1. Due to the different distances between the support rod 5 and the hanging groove 32, when the rotating shaft 14 is rotated to make the eccentric wheel 4 rotate, different tooth grooves 41 cooperate with the support rod 5, pushing the support rod 5 to slide into the hanging groove 32 of one or some counterweights 3. When the eccentric wheel 4 continues to rotate until the support rod 5 loses the pushing effect of the tooth groove 41, the reset member pushes the support rod 5 outward, so that it is separated from the hanging groove 32 of one or some counterweights 3, and the support rod 5 is always kept against the tooth groove 41.
[0057] The reset member may be an elastic reset member 131, specifically a spring, the dumbbell rack 1 is provided with a guide slot 13, the support rod 5 is provided with a latch 53 inserted into the guide slot 13, and the elastic reset member 131 is located between the bottom wall of the guide slot 13 and the latch 53. When the elastic reset member 131 is a spring, one end thereof close to the latch 53 may be configured to be sleeved on the latch 53.
[0058] In order to balance the forces at both ends of the support rod 5 and make it more stable, the present embodiment provides two latches 53 respectively located at both ends of the support rod 5 , and both the guide grooves 13 and the elastic reset members 131 are two and correspond one to one with the two latches 53 .
[0059] In this embodiment, in order to balance the forces at both ends of the support rod 5 when sliding, and to make it more stable, two eccentric wheels 4 are provided and respectively abut against the two ends close to the support rod 5. Specifically, the two eccentric wheels 4 are respectively located on the left and right sides of the dumbbell rack 1.
[0060] In this embodiment, Figure 5 and Figure 6 As shown, in order to facilitate the rotation of the eccentric wheel 4 so that the tooth grooves 41 at different positions on the eccentric wheel 4 cooperate with the support rod 5, the tooth grooves 41 are set as arc grooves, and the two ends close to the support rod 5 are provided with abutment ends 51, and the two abutment ends 51 respectively abut in the arc grooves on the two eccentric wheels 4. A stopper 52 is provided on the outer side of each abutment end 51, and the two eccentric wheels 4 are located between the two stoppers 52. The two stoppers 52 can further prevent the support rod 5 from deviating left and right.
[0061] Among them, since the handle 2 is synchronously rotated with the rotating shaft 14, in order to prevent the user from accidentally rotating the handle 2 when using the dumbbell, this embodiment is provided with a locking mechanism on the dumbbell rack 1 for locking the rotating shaft 14 and the dumbbell rack 1. The function of the locking mechanism is to prevent the rotating shaft 14 from rotating relative to the dumbbell rack 1 when the user uses the dumbbell. It can adopt the structure in the prior art, for example, the locking mechanism is set between the handle 2 and the dumbbell rack 1, and it can be a structure using a plug-in positioning pin. When adjustment is required, the locking mechanism is unlocked.
[0062] In this embodiment, Figure 2 and Figure 7As shown, in order to facilitate the adjustment of the addition and subtraction of the counterweight blocks 3, the hanging grooves 32 of all the counterweight blocks 3 are located on the same side of the rotating shaft 14. The opening groove 31 is set as a U-shaped groove, and the hanging groove 32 is located on a side wall of the U-shaped groove, and in the U-shaped grooves of at least two counterweight blocks 3, the side wall with the hanging groove 32 is distributed in a stepped manner from the first block to the tail block. Specifically, the positions of the openings of the hanging grooves 32 are different. For example, when the support rod 5 slides into the hanging groove 32 of the head block configuration block, it is still outside the hanging groove 32 of the tail block counterweight block 3. This setting structure ensures that at least two counterweight blocks 3 will not be selected at the same time, thereby making more weight levels adjustable.
[0063] In this embodiment, as a specific implementation method, Figure 2 and Figure 7 As shown, in the U-shaped grooves of all the counterweight blocks 3, the distance between one side wall provided with the hanging groove 32 and the other side wall gradually increases from the side close to the handle 2 to the side away from the handle 2 in a step-like manner, and the diameter of the counterweight block base 11 gradually increases from the side close to the handle 2 to the side away from the handle 2 in a step-like manner;
[0064] Alternatively, in the U-shaped grooves of all the counterweights 3, the distance between one side wall provided with the hanging groove 32 and the other side wall gradually approaches from the side close to the handle 2 to the side far from the handle 2 in a step-like manner, and the diameter of the counterweight base 11 gradually decreases from the side close to the handle 2 to the side far from the handle 2 in a step-like manner. This arrangement enables the counterweights 3 to be assembled in sequence from the side close to the handle 2 to the side far from the handle 2 when assembling the counterweights 3.
[0065] In this embodiment, in order to facilitate the user to select and adjust the weight level, a dial 6 may be provided on the dumbbell rack 1 and rotate synchronously with the handle 2 , and a pointer may be provided on the dumbbell rack 1 at the same time.
[0066] Working principle description:
[0067] When it is necessary to increase or decrease the counterweight 3, the eccentric wheel 4 is rotated by rotating the handle 2. When the eccentric wheel 4 rotates, different tooth grooves 41 cooperate with the support rod 5, so that the support rod 5 slides along the dumbbell rack 1 under the action of the eccentric wheel 4 and the reset member. When the support rod 5 slides into the hanging groove 32 of a counterweight 3, the counterweight 3 is assembled on the dumbbell rack 1, and its opening groove 31 is spliced on the outside of the counterweight base 11. Since the support rod 5 is located in the hanging groove 32 of the counterweight 3, the dumbbell rack 1 can be lifted by lifting it upward. When the support rod 5 slides out of the hanging groove 32 of a counterweight 3, the counterweight 3 is separated from the dumbbell rack 1, and the dumbbell rack 1 is lifted upward, and the counterweight 3 will remain on the counterweight 3 placement seat.
[0068] The present utility model is not limited to the above optional implementation modes. Under the premise of not conflicting with each other, the various schemes can be combined arbitrarily. Anyone can derive other forms of products under the inspiration of the present utility model. However, no matter what changes are made in their shapes or structures, all technical schemes that fall within the scope defined by the claims of the present utility model fall within the protection scope of the present utility model.
Claims
1. A dumbbell with easy-to-adjust weight, characterized in that: The dumbbell assembly comprises a handle and at least one group of dumbbell assemblies connected to the handle; the dumbbell assembly comprises: A dumbbell rack with a weight base; A support rod is slidably disposed on the dumbbell rack and the sliding direction is perpendicular to the axis of the dumbbell rack; A plurality of counterweight blocks are arranged in parallel along the axial direction of the dumbbell rack, each of the counterweight blocks is provided with an opening groove which is opened upward and is used for splicing on the outer side of the counterweight block base, and a hanging groove is provided in the opening groove for hanging the counterweight block on the support rod; and, The adjusting mechanism is arranged on the dumbbell rack, and the adjusting mechanism drives the supporting rod to slide back and forth along the dumbbell rack so that the supporting rod slides into or out of the hanging groove of the counterweight block.
2. A dumbbell with easily adjustable weight according to claim 1, characterized in that: The adjustment mechanism includes a rotating shaft rotatably arranged on the dumbbell rack and connected to the handle, an eccentric wheel sleeved on the rotating shaft, and a reset member. A plurality of tooth grooves cooperating with the support rod are arranged around the eccentric wheel. When the rotating shaft is driven to rotate by the handle and the rotating shaft drives the eccentric wheel to rotate, the support rod abuts against different tooth grooves under the rotation of the eccentric wheel, so that the support rod slides into or out of the hanging grooves of different counterweight blocks; The reset member is arranged between the support rod and the dumbbell rack and is used to make the support rod abut against the tooth groove.
3. A dumbbell with easily adjustable weight according to claim 2, characterized in that: The reset member is an elastic reset member, the dumbbell rack is provided with a guide groove, the support rod is provided with a latch inserted in the guide groove, and the elastic reset member is located between the bottom wall of the guide groove and the latch.
4. A dumbbell with easily adjustable weight according to claim 3, characterized in that: There are two latches, which are respectively located at two ends of the support rod; there are two guide grooves and two elastic reset members, which respectively correspond to the two latches one by one.
5. A dumbbell with easily adjustable weight according to claim 2, characterized in that: There are two eccentric wheels, which are respectively against two ends close to the support rod.
6. A dumbbell with easily adjustable weight according to claim 5, characterized in that: The tooth groove is an arc-shaped groove, and abutment ends are provided near the two ends of the support rod, and the two abutment ends abut against the arc-shaped grooves on the two eccentric wheels respectively; A stopper is provided on the outer side of each abutting end, and the two eccentric wheels are located between the two stoppers.
7. A dumbbell with easily adjustable weight according to claim 2, characterized in that: The dumbbell rack is provided with a locking mechanism for locking the rotating shaft and the dumbbell rack.
8. The dumbbell with easily adjustable weight according to claim 1, characterized in that: The dumbbell components are in two groups and are symmetrically arranged on the left and right sides of the handle.
9. A dumbbell with easily adjustable weight according to claim 2, characterized in that: The mounting grooves of all the counterweight blocks are located on the same side of the rotating shaft; The opening groove is a U-shaped groove, the hanging groove is located on a side wall of the U-shaped groove, and in the U-shaped grooves of at least two counterweight blocks, a side wall with the hanging groove is distributed in a stepped manner from the first block to the last block.
10. A dumbbell with easily adjustable weight according to claim 9, characterized in that: In the U-shaped grooves of all the counterweight blocks, the distance between one side wall provided with the hanging groove and the other side wall gradually increases in a step-like manner from the side close to the handle to the side far from the handle, and the diameter of the counterweight block base gradually increases in a step-like manner from the side close to the handle to the side far from the handle; Alternatively, in the U-shaped grooves of all the counterweight blocks, the distance between one side wall with the hanging groove and the other side wall gradually approaches in a step-like manner from the side close to the handle to the side far from the handle, and the diameter of the counterweight block base gradually decreases in a step-like manner from the side close to the handle to the side far from the handle.