Inflatable Flexible Dumbbell and Its Manufacturing Method

Description

TECHNICAL FIELD

The present invention relates to the technical field of dumbbells, in particular to inflatable flexible dumbbell that prevents impact damage to the human body, indoor floor tiles, floors, and the like, while also providing excellent noise reduction effects.

BACKGROUND OF THE ART

As a kind of fitness equipment used to enhance muscle strength and endurance, dumbbells can be divided into two categories: fixed weight dumbbells and adjustable weight dumbbells. The weight of a fixed-weight dumbbell cannot be changed, and it is generally composed of a metal rod and one or two weight plates. The weight-adjustable dumbbell allows users to adjust the weight according to their own needs. The common way is to add or remove the weight plate. Dumbbells are usually made of cast iron, rubber or other durable materials to ensure their weight characteristics and durability.

In the early days, people tended to go to professional gyms for fitness. However, with the increasing popularity of fitness activities, many people begin to choose to carry out fitness exercises in their living rooms and balconies. However, as living rooms or balconies are mostly paved with tiles or hardwood floors, dumbbells may frequently cause impact damage to indoor flooring surfaces such as tiles and hardwood floors, as well as human bodies during use. Moreover, in multi-story building environments, structural-borne noise generated by dumbbell-to-floor impacts may propagate to disturb dwellers below.

Prior Art Reference: CN218740036U “Training Filler” discloses a dumbbell comprising: a main body, two partition plates, and filler material; wherein the main body is partitioned by left and right partition plates into: two end filler chambers that are mutually isolated, and a central sealed cavity section; the central sealed cavity section being separated from its two end filler portions by respective partition plates, with the central sealed cavity section serving as a grip handle, and filler portions containing at least particulate fillers constituting weighted blocks at both ends of the dumbbell.

Filler material at both ends of the dumbbell functions as counterweights, typically comprising sand, crushed rock, or steel balls; while the grip handle or filler compartments are constructed of plastic material. This dumbbell suffers from the following technical deficiencies: The mutually isolated end filler chambers necessitate separate filling procedures during manufacturing, requiring independent injection of particulate fillers into each chamber; Consequent weight imbalance between end chambers occurs with statistical significance, resulting in asymmetric mass distribution that adversely impacts user experience during dynamic exercises.

SUMMARY

In view of this, the technical problem to be solved by the present invention is to provide inflatable flexible dumbbell.

The technical solution adopted by the present invention to resolve the above technical problems is: Inflatable flexible dumbbell comprising first counterweight section, second counterweight section, and grip section;

First counterweight section includes first inflatable bladder having first air cavity and filler in first air cavity; Second counterweight section includes second inflatable bladder having second air cavity and filler in second air cavity, and grip section includes rigid tubular body having third air cavity and filler in third air cavity;

Rigid tubular body, first inflatable bladder and second inflatable bladder are made of plastic material; First end of rigid tubular body bordering inner end of first inflatable bladder and separating first air cavity from third air cavity by first separation bonding membrane having first through hole;

Second end of rigid tubular body bordering inner end of second inflatable bladder; And separating second air cavity from third air cavity by second separation bonding membrane having second through hole;

The three cavities of first air cavity, second air cavity and third air cavity are communicated through first through hole and second through hole; First through hole and second through hole have apertures for filler to pass through.

The technical solution adopted by the present invention to resolve the above technical problems is: rigid tubular body, first inflatable bladder and second inflatable bladder are one-piece rotationally molded parts;

Rigid tubular body compromises straight tubular small-diameter segment in the middle and first and second enlarged diameter segments on both sides;

First enlarged diameter segment wraps the inner edge of first inflatable bladder, and first enlarged diameter segment and first inflatable bladder are joined by first separation bonding membrane;

Second enlarged diameter segment wraps the inner edge of second inflatable bladder, and second enlarged diameter segment and second inflatable bladder are joined by second separation bonding membrane;

Intermediate transition membrane is interposed between rigid tubular body and inflatable bladder, and a portion of rigid tubular body adjacent to the intermediate transition membrane and a portion of inflatable bladder adjacent to the intermediate transition membrane are fusion-bonded to the intermediate transition membrane to form a separation bonding membrane.

The technical solution adopted by the present invention to resolve the above technical problems is: rigid tubular body, first inflatable bladder, second inflatable bladder, first separation bonding membrane and second separation bonding membrane are fabricated exclusively from PVC (polyvinyl chloride) material; Filler material comprises at least one of sand particles, iron shot, or steel balls.

The technical solution adopted by the present invention to resolve the above technical problems is: first enlarged diameter segment is first flared segment; Second enlarged diameter segment is second flared segment;

First inflatable bladder constitutes first spherical body, and second inflatable bladder constitutes second spherical body.

The outer peripheral surface of first flared segment smoothly transitions with the outer peripheral surface of first spherical body, the outer peripheral surface of second flared segment smoothly transitions with the outer peripheral surface of second spherical body smoothly transition;

The depth of first flared segment or second flared segment is H, and the radius of first spherical body or second spherical body is R; The depth H and the radius R satisfy: 0.2 R<H<0.8 R.

The technical scheme adopted by the invention to solve the above technical problems is: Inflatable flexible dumbbell, which comprises first counterweight section, second counterweight section and a hard grip section;

First counterweight section includes first inflatable bladder having first air cavity; Second counterweight section includes second inflatable bladder having second air cavity; The grip comprises a plastic-textured rigid tubular body having third air cavity;

Rigid tubular body, first inflatable bladder and second inflatable bladder are all made of plastic material, and the materials bordering first flared segment with first spherical body and second flared segment with second spherical body are fused with each other; First air cavity, second air cavity and third air cavity are provided with fillers.

The technical solution adopted by the present invention to resolve the above technical problems is: rigid tubular body comprises a middle straight tubular small-diameter segment, first flared segment and second flared segment; First inflatable bladder is first spherical body, and second inflatable bladder is second spherical body; First flared segment borders first spherical body and second flared segment borders second spherical body;

First air cavity is in communication with third air cavity, second air cavity is in communication with third air cavity, and at least one of second inflatable bladders of first inflatable bladders is provided with an inflation valve core; First air cavity, second air cavity and third air cavity are provided with fillers and gas.

The technical scheme adopted by the invention to solve the above technical problems is: a manufacturing method of inflatable flexible dumbbell, which comprises the following steps:

Step S1: Adding first plastic raw material into first mold cavity of a rotational molding die, and sealing the interface between first mold cavity and second mold cavity with a intermediate transition membrane.

Step S2: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats first mold cavity, first plastic raw material of first mold cavity is gradually and uniformly coated, melted and adhered to the inner wall of first mold cavity and first surface of first intermediate transition membrane under the action of gravity and heat energy, and first plastic raw material is melted into first intermediate transition membrane;

Step S3: Cooling and setting to form first inflatable bladder;

Step S4: Adding second plastic material into second mold cavity of a rotational molding die having first inflatable bladder and closing a boundary between second mold cavity and the third mold cavity with second intermediate transition membrane;

Step S5: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats second mold cavity, second plastic raw material of second mold cavity is gradually uniformly coated, melted and adhered to the inner wall of second mold cavity and second surface of first intermediate transition membrane and first surface of second intermediate transition membrane under the action of gravity and heat energy, and second plastic raw material is melted into first intermediate transition membrane and second intermediate transition membrane;

Step S6: Cooling and setting to form rigid tubular body, two sides of first intermediate transition membrane are respectively fusion-bonded to with first plastic raw material and second plastic raw material to form first separation bonding membrane, and first inflatable bladder and rigid tubular body are integrally connected with first separation bonding membrane;

Step S7: Adding first plastic material into a third mold cavity of a rotational molding die having first inflatable bladder and rigid tubular body;

Step S8: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats the third mold cavity, first plastic raw material of the third mold cavity is gradually and uniformly coated, melted and adhered to the inner wall of the third mold cavity and second surface of second intermediate transition membrane under the action of gravity and heat energy, and first plastic raw material is melted into second intermediate transition membrane;

Step S9: Cooling and setting to form second inflatable bladder, two sides of second intermediate transition membrane are respectively fusion-bonded to first plastic raw material and second plastic raw material to form second separation bonding membrane, and second inflatable bladder and rigid tubular body are integrally connected with second separation bonding membrane;

Step S10: The mold is opened and the molded article including rigid tubular body, and first inflatable bladder, and second inflatable bladder is taken out from the mold.

The technical scheme adopted by the invention to solve the above technical problems is: It also comprises the following steps:

Step S11: Positioning the molded article on a jig, forming individual injection ports in first or second inflatable bladder via a piercing apparatus, inflating the article within the jig to prescribed dimensions, and thereby forming air cavities within rigid tubular body, first inflatable bladder, and second inflatable bladder respectively.

Step S12: Using a piercing apparatus to continuously pass through the inner cavities of rigid tubular body, first inflatable bladder, and second inflatable bladder through the injection hole to perforate first separation bonding membrane and second separation bonding membrane to form first through hole and second through hole;

Step S13: Injecting fillers into three cavities of first air cavity, second air cavity and third air cavity at high pressure through one side of the injection hole, and then inserting an inflation valve core at the injection hole to close the injection hole, wherein first air cavity, second air cavity and third air cavity have air gaps so that filler materials in the three cavities can flow with each other.

The technical scheme adopted by the invention to solve the above technical problems is:

It also comprises the following steps:

Step S11: Positioning the molded article on the jig, using the injection holes formed in first inflatable bladder and second inflatable bladder respectively by the piercing apparatus, the two injection holes are positioned on a straight line, and further inflating the molded article to prescribed dimensions in the jig, respectively, in rigid tubular body; An air cavity is formed within first inflatable bladder and second inflatable bladder;

Step S12: Using a piercing apparatus to continuously pass through the inner cavities of rigid tubular body, first inflatable bladder, and second inflatable bladder through the injection hole to perforate first separation bonding membrane and second separation bonding membrane to form first through hole and second through hole;

Step S13: Injecting filler material into three cavities of first air cavity, second air cavity and third air cavity at high pressure through the injection holes on both sides, and then inserting the inflation valve core at the injection hole to close the injection hole.

The technical solution adopted by the present invention to resolve the above technical problems is: Filler material comprises at least one of sand particles, iron shot, or steel balls;

First plastic raw material is a low-density PVC material, and second plastic raw material is a high density PVC material.

Compared with the prior art, the invention has the advantages that inflatable bladder and the gas contained therein make the two counterweight sections of the dumbbell have excellent elasticity while maintaining sufficient weight. This design not only avoids the risk of dumbbell injuring people due to accidental drop during use, but also effectively prevents the dumbbell from bruising the surface of hard objects such as floor, and improves the safety of use and environmental protection.

Further, air cavity of the weight section and air cavity of grip section are both filled with fillers, and the weights of the two counterweight sections will be relatively uniform. Because there is filler in air cavity of grip section, under the premise of equal weight, the volume of the dumbbell is smaller and the packaging and transportation cost is lower.

In addition, the three cavities are connected, and filler can be poured from only one opening or double-headed, which improves the convenience and efficiency of production and reduces the manufacturing cost. Moreover, as few opening holes as possible also keep the integrity and air tightness of the peripheral wall to the maximum extent, ensuring its stability and durability in long-term use.

DESCRIPTION OF THE DRAWINGS

The following detailed description of the invention will be provided in conjunction with the accompanying drawings and preferred embodiments. Persons skilled in the art will appreciate, however, that these drawings are drawn solely for the purpose of illustrating the preferred embodiments and should therefore not be construed as limiting the scope of the invention. Furthermore, unless otherwise indicated, the drawings are merely schematically to conceptually represent the composition or construction of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

FIG. 1 is a perspective view of inflatable flexible dumbbell;

FIG. 2 is a front view of inflatable flexible dumbbell;

FIG. 3 is a cross-sectional view of inflatable flexible dumbbell;

FIG. 4 is a cross-sectional view of a plastic part of inflatable flexible dumbbell.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. A person skilled in the art will appreciate that the descriptions are merely descriptive and illustrative, and shall not be construed as limiting the protection scope of the present invention.

It should be noted that similar reference numerals designate corresponding items throughout the drawings, and thus once an item is defined in one drawing, it need not be further defined or explained in subsequent drawings.

In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms, “upper”, “lower”, “front”, “back”, “left”, “right”, “inner”, “outer”, etc. is based on the orientation or positional relationship shown in the drawings, and is merely for convenience and simplification of the description of the present application, and does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be construed as a limitation of the present application. However, the terms “first” and “second” are described only for convenience of understanding, and have no other directional meaning, and are not intended to limit the present invention.

As shown in FIG. 1, this embodiment provides inflatable flexible dumbbell, which include s a rigid grip section 1 in the middle and first counterweight section 2 and second counterweight section 3 on both sides.

As shown in FIGS. 1-4, first counterweight section 2 includes first inflatable bladder 20 having first air cavity Q1 and filler in first air cavity Q1. Second counterweight section 3 includes second inflatable bladder 30 having second air cavity Q2 and filler in second air cavity Q2.

Further, as shown in FIGS. 1 to 4, grip section 1 includes rigid tubular body 10 having third air cavity Q3 and filler in third air cavity Q3. Rigid tubular body 10, first inflatable bladder 20, and second inflatable bladder 30 are made of plastic.

Wherein first end of rigid tubular body 10 borders inner end of first inflatable bladder 20 and second end of rigid tubular body 10 borders inner end of second inflatable bladder 30.

The three cavities of first air cavity Q1, second air cavity Q2, and third air cavity Q3 are communicated with each other, and filler material can flow with each other within the three cavities.

Although the peripheral walls of these cavities are made of lightweight plastic, it is difficult to achieve the counterweight effect required by traditional dumbbells with the simple plastic weight. Therefore, the present embodiment not only realizes the perfect combination of soft and hard materials, but also ensures the reasonable counterweight of the dumbbell through the plastic shell and filler with higher internal density, so that users can feel moderate resistance during exercise, and effectively improves the training effect. Preferably, filler is at least one of sand particles, iron sand, and steel balls.

In this embodiment, the three air cavities communicate with each other, which means that only one opening hole can be made in the surface of the dumbbell, and filler can be poured from only one opening hole. This design not only maximizes the integrity and airtightness of the outer peripheral wall, but also further enhances the structural strength of the dumbbell, ensuring its stability and durability in long-term use. At the same time, this integrated filling method also greatly improves the convenience and efficiency of production, reduces manufacturing costs, and enables more users to enjoy the fitness fun brought by this innovative product at a more affordable price.

The grip section 1 also adopts a design comprising a plastic shell with an air cavity filled with filler material. This configuration avoids bending deformation caused by a light middle section and heavy ends, thereby extending the service life of the dumbbell.

More importantly, the gas contained in inflatable bladder and air cavity makes the two counterweight sections of the dumbbell have excellent elasticity while maintaining sufficient weight. This design not only avoids the risk of dumbbells injuring people due to accidental falling during use, but also effectively prevents dumbbells from bruising hard surfaces such as floors, thus improving the safety of use and environmental protection.

Further, as shown in FIGS. 3-4, first separation bonding membrane 4 having first through hole K1 is provided between rigid tubular body 10 and first inflatable bladder 20, and first separation bonding membrane 4 separates first air cavity Q1 and third air cavity Q3. Second separation bonding membrane 5 having second through hole K2 is provided between rigid tubular body 10 and second inflatable bladder 30, and second separation bonding membrane 5 separates second air cavity Q2 and third air cavity Q3. The apertures of first through hole K1 and second through hole K2 are allowed to pass through filler.

In the present embodiment, rigid tubular body 10, first inflatable bladder 20, and second inflatable bladder 30 are one-piece rotationally molded parts. Intermediate transition membrane is provided between rigid tubular body 10 and inflatable bladder, and a portion of rigid tubular body 10 adjacent to the intermediate transition membrane and a portion of inflatable bladder adjacent to the intermediate transition membrane are melted and integrated with the intermediate transition membrane to form a partition membrane.

A manufacturing method of the inflatable flexible dumbbell provided by the present embodiment comprises the following steps:

Step S1: adding first plastic raw material into first mold cavity of a rotational molding die, and sealing the interface between first mold cavity and second mold cavity with a intermediate transition membrane.

Step S2: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats first mold cavity, first plastic raw material of first mold cavity is gradually and uniformly coated, melted and adhered to the inner wall of first mold cavity and first surface of first intermediate transition membrane under the action of gravity and heat energy, and first plastic raw material is melted into first intermediate transition membrane.

Step S3: Cooling and setting to form first inflatable bladder 20.

Step S4: Adding second plastic material into second mold cavity of a rotational molding die having first inflatable bladder 20 and closing a boundary between second mold cavity and the third mold cavity with second intermediate transition membrane;

Step S5: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats second mold cavity, second plastic raw material of second mold cavity is gradually uniformly coated, melted and adhered to the inner wall of second mold cavity and second surface of first intermediate transition membrane and first surface of second intermediate transition membrane under the action of gravity and heat energy, and second plastic raw material is melted into first intermediate transition membrane and second intermediate transition membrane.

Step S6: Cooling and setting to form rigid tubular body 10, two sides of first intermediate transition membrane are respectively fusion-bonded to with first plastic raw material and second plastic raw material to form first partition membrane 4, and first inflatable bladder 20 and rigid tubular body 10 are integrally connected with first separation bonding membrane 4.

Step S7: Adding first plastic material into a third mold cavity of a rotational molding die having first inflatable bladder 20 and rigid tubular body 10.

Step S8: Turning on the rotational molding equipment, the rotational molding die continuously rotates and heats the third mold cavity, first plastic raw material of the third mold cavity is gradually and uniformly coated, melted and adhered to the inner wall of the third mold cavity and second surface of second intermediate transition membrane under the action of gravity and heat energy, and first plastic raw material is melted into second intermediate transition membrane;

Step S9: Cooling and setting to form second inflatable bladder 30, two sides of second intermediate transition membrane are respectively fusion-bonded to first plastic raw material and second plastic raw material to form second separation bonding membrane 5, and second inflatable bladder 30 and rigid tubular body 10 are integrally connected with second separation bonding membrane 5.

Step S10: The mold is opened and the molded article 10 including rigid tubular body 20, and first inflatable bladder 20, and second inflatable bladder 30 is taken out from the mold.

Step S11: Positioning the molded article on a jig, forming individual injection ports in first inflatable bladder 20 or second inflatable bladder 30 via a piercing apparatus, inflating the article within the jig to prescribed dimensions, and thereby forming gas cavity within rigid tubular body 10, first inflatable bladder 20, and second inflatable bladder 30 respectively.

Step S12: Using a piercing apparatus to continuously pass through the inner cavities of rigid tubular body 10, first inflatable bladder 20, and second inflatable bladder 30 through the injection hole to perforate first separation bonding membrane 4 and second separation bonding membrane 5 to form first through hole K1 and second through hole K2;

Step S13: Injecting Fillers into three cavities of first air cavity Q1, second air cavity Q2 and third air cavity Q3 through one side of the injection hole, and then inserting an inflation valve core G at the injection hole to close the injection hole, wherein first air cavity Q1, second air cavity Q2 and third air cavity Q3 have air gaps so that filler materials in the three cavities can flow with each other.

In this embodiment, the piercing apparatus forms injection holes on a straight line on first inflatable bladder 20 and second inflatable bladder 30, respectively, so as to realize double-head perfusion and improve production efficiency. Furthermore, an inflation valve core G is formed at both ends of the dumbbell.

Preferably, rigid tubular body 10, first inflatable bladder 20, second inflatable bladder 30, first partition membrane 4 and second partition membrane 5 are fabricated exclusively from PV C (polyvinyl chloride) material. Both first plastic raw material and second plastic raw material are paste resins. First plastic raw material is a low density PVC material, and second plastic raw material is a high density PVC material.

All components are made of PVC material, which means that during the rotomolding process, the individual components are able to achieve the desired molten state at almost the same temperature conditions, thus ensuring excellent fusion effect between the parts.

In terms of structure, because all components are made of the same material, their thermal expansion coefficients and thermal shrinkage are similar, so that a product with strong integrity and stable structure can be formed after cooling and solidification. In particular, first separation bonding membrane 4 and second separation bonding membrane 5 are the key parts connecting rigid tubular body 10 and inflatable bladder, and they melt the materials of both sides of the components on the same intermediate transition membrane, so that the three are integrated into a whole to achieve perfect welding, effectively avoid forming defects caused by material differences ensure good welding, and further improve the strength of the junction between rigid tubular body 10 and inflatable bladder. Consequently, during prolonged use, these junction areas are less prone to molding defects such as cracking or delamination, thus significantly extending the product's service life.

Structurally, as shown in FIGS. 1-4, rigid tubular body 10 compromises straight tubular small-diameter segment 11 in the middle and First enlarged diameter segment 12 and second enlarged diameter segment 13 on both sides. First enlarged diameter segment 12 wraps the inner edge of first inflatable bladder 20, and first enlarged diameter segment 12 and first inflatable bladder 20 are joined by first partition membrane 4. Second enlarged diameter segment 13 wraps the inner edge of second inflatable bladder 30, and second enlarged diameter segment 13 and second inflatable bladder 30 are joined by second partition membrane 5; First diameter-enlarged section 12 and second diameter-enlarged section 13 support inflatable bladder and improve the connection strength between the two.

Further, first enlarged diameter segment 12 is first flared segment. Second enlarged diameter segment 13 is second flared segment. First inflatable bladder 20 constitutes first spherical body, and second inflatable bladder 30 constitutes second spherical body. The outer peripheral surface of first flared segment smoothly transitions with the outer peripheral surface of first spherical body, the outer peripheral surface of second flared segment smoothly transitions with the outer peripheral surface of second spherical body smoothly transition.

First diameter-enlarged section 12 and second diameter-enlarged section 13 are skillfully designed as flared segments, and the shapes of first diameter-enlarged section 12 and second diameter-enlarged section 13 are gradually expanded and then fittingly connected with the spherical inflatable bladder, which not only realizes a smooth transition of the pipe diameter, but also makes the outer peripheral surfaces of different components realize a seamless and smooth transition. This design optimizes the stress distribution functionally, reduces the potential stress concentration points caused by sudden shape changes, and also brings structural beauty and cleanliness from an aesthetic point of view. Smooth and continuous curved lines give the entire device a streamlined and elegant appearance and enhance the visual beauty. The smoothly contoured design provides refined tactile feedback at all junctions without noticeable protrusions or depressions. This prevents potential scratches or abrasions to users or objects during operation, while also significantly facilitating daily cleaning and maintenance due to minimized accumulation of dust grime, or residues.

Further, in the design details of first flared segment and second flared segment, this embodiment preferably also introduces key dimensional parameters-depth H and radius R, and the ingenious proportional relationship between these two parameters is not only related to the beauty and smoothness of the structure, but also directly reflects the optimization of use strength and performance.

Specifically, the depth of first flared segment or second flared segment is accurately set to H, and the radius of first or second spherical body connected thereto is R. Ideal ratio range between depth H and radius R: 0.2 R<H<0.8 R. The setting of this ratio range aims to balance structural strength and aesthetics, and ensure the best visual effect and user experience while meeting the intensity of use.

When the depth H is within this ratio range, the junction of the flared segment and the spherical body can form a transition surface that is neither too steep nor too gentle. Such design not only effectively distributes stress to reduce stress concentration induced by geometric discontinuities, thereby enhancing the fatigue resistance and service life of the entire structure, but also ensures unimpeded fluid flow within the piping system, reducing energy consumption and noise generation.

Inflatable flexible dumbbell according to the present invention has been described herein. Specific exemplary embodiments are employed to illustrate the principles and implementations of the invention. The foregoing description of embodiments is provided solely to aid in comprehending the core inventive concepts of the present invention. It should be pointed out that several improvement and modifications can be made to the present invention without departing from the principles of the present invention, and these improvement and modifications also fall within the scope of the claims of the present invention.