Trundle device

Abstract

The caster device comprises a container with a downward opening, and the container comprises a top plate and a mounting bracket capable of vertically sliding in the container. In addition, one or more trundles are attached to one side of the mounting bracket and are in contact with the ground. And at least one elastic component is pressed on the lower side of the top plate of the container on the other side of the mounting bracket. When a predetermined weight is applied to an object supported by a container of the caster device, the elastic component is compressed, so that the bottom edge of the container is in contact with the ground. The friction between the trundle device and the ground is increased, so that the trundle device is not easy to move. The elastic assembly is a spring, for example. The caster device can provide better stability.

Description

Technical Field

[0001] The present invention is a caster device, and more particularly, a caster device designed to provide better stability when a predetermined weight is applied to a supported object. Background Art

[0002] Caster assemblies are widely used in various applications, such as office chairs, shopping carts, and mobile devices, to facilitate easy movement of the supported object. Traditionally, caster assemblies generally include a caster wheel mounted on a bracket, which is then mounted and fixed to the bottom of the object. Although these traditional caster assemblies allow for easy movement, they can also cause unexpected movement or instability when a user applies weight to the supported object, such as sitting on an office chair.

[0003] To address this problem, some caster device designs have incorporated locking mechanisms that require manual activation to lock the caster. However, these locking mechanisms can be inconvenient because they require the user to manually activate or unlock each time an object is moved or stabilized.

[0004] Another way to increase the stability of a caster assembly is to use larger or wider casters, which provide more contact area with the ground and therefore create more friction. However, larger or wider casters may not be suitable for all applications because they may increase the overall size and weight of the caster assembly, making it impractical for certain objects or environments.

[0005] Therefore, there is a need for an improved caster device that can provide better stability when a predetermined weight is applied to the supported object without the need for manual activation or unlocking, and without the need for using a larger or wider caster. Therefore, how to design such a caster device is a problem that is worth considering by those with ordinary knowledge in the art. Summary of the invention

[0006] An object of the present invention is to provide a caster device that can provide better stability when a predetermined weight is applied to a supported object.

[0007] Based on the above-mentioned and other purposes, the present invention provides a caster device, which includes a container that opens downward and includes a top plate, and a mounting bracket that can slide vertically inside the container. In addition, one or more casters are attached to one side of the mounting bracket and contact the ground. On the other side of the mounting bracket, at least one elastic component is pressed on the lower side of the top plate of the container. When a predetermined weight is applied to the object supported by the container of the caster device, the elastic component is compressed, so that the bottom edge of the container contacts the ground. This increases the friction between the caster device and the ground, making the caster device difficult to move. Among them, the elastic component is, for example, a spring.

[0008] In the above caster device, the container is composed of an upper container and a lower container. The side wall of the lower container and the side wall of the upper container each have an interlocking structure, and the lower container and the upper container are assembled through the interlocking structure. After assembly, the side wall of the upper container surrounds the side wall of the lower container.

[0009] The caster device described above further includes at least one rotation damper, which is located between the side wall of the lower container and the side wall of the upper container, and includes a gear, which passes through a through hole in the side wall of the lower container and matches with the rack on the mounting bracket.

[0010] In the caster device described above, both sides of the mounting bracket include slide rails that cooperate with corresponding guide grooves in the container.

[0011] The caster device described above also includes a fixing screw, which is arranged on the container and is used to fix the container to the bottom of the object.

[0012] The caster device described above further includes at least one buffer mechanism, wherein the buffer mechanism can be the above-mentioned rotary shock absorber.

[0013] In the caster device described above, the caster is a double-wheel swivel caster.

[0014] In the caster device described above, the caster includes a tread made of thermoplastic rubber or polyurethane.

[0015] In order to achieve the above and other purposes, the present invention adopts technical means, components and their effects, and a preferred embodiment is described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 and Figure 2 Shown are three-dimensional views of the caster device at different angles.

[0017] Figure 3 Shown is the internal structure of the caster device.

[0018] Figure 4 The diagram shows the changes of the caster device before and after being subjected to force.

[0019] Figure 5 A three-dimensional view of the upper container viewed from above is shown.

[0020] Figure 6 A perspective view of the lower container half is shown.

[0021] Figure 7 An embodiment of the rotary damper of the present invention is shown.

[0022] Figure 8 Illustrated is an embodiment of the double-wheel swivel caster of the present invention.

[0023] Fig. 9 Another application of the caster device of the present invention is shown. DETAILED DESCRIPTION

[0024] Please also refer to Figure 1 , Figure 2 , Figure 3 ,and Figure 4 , shows an embodiment of a caster device for supporting an object and suitable for being placed on the ground. Figure 1 and Figure 2 The drawings are three-dimensional images of the caster device at different angles. Figure 3 The internal structure of the caster device is shown. Figure 4 The diagram shows the changes of the caster device before and after the force is applied. In this embodiment, the caster device 100 includes a container 110, and the container 110 has a downward opening 114a and a top plate 112a. In addition, the caster device 100 also includes a fixing screw 116 for fixing the container 110 to the bottom of an object. In this embodiment, the object can be an office chair, an office desk, or a living room sofa, etc. By installing multiple caster devices 100 on the object, the object can be easily moved.

[0025] Please refer to Figure 3 The caster device 100 further includes a mounting bracket 120 and at least one caster 130 (two in this embodiment), wherein the mounting bracket 120 is disposed in the container 110 and is adapted to slide vertically in the container 110. In addition, the caster 130 is mounted on one side of the mounting bracket 120 and is in contact with the ground 10. In addition, in this embodiment, compared to the caster 130, the elastic component 140 is located on the other side of the mounting bracket 120 and is in two pieces, and the upper portion of the elastic component 140 is pressed against the lower side of the container top plate 112a. In addition, the mounting bracket 120 further includes two spring slots 126 for mounting springs (i.e., the elastic component 140).

[0026] In the present embodiment, the elastic component 140 is a spring, but a person having ordinary knowledge in the art may also select other elastic components. For example, the elastic component includes an elastic block or gasket made of an elastic material, such as rubber, silicone or polyurethane, which provides elastic support due to its inherent properties. In addition, the elastic component may also be provided with a soft and elastic support by a gel pad made of a deformable gel material, which helps to reduce vibration and impact. The elastic component may also be a stack of flat, curved metal strips that are clamped together to form a leaf spring, which has a soft and strong support structure. Alternatively, the elastic component may also be a torsion bar, which is a long, cylindrical metal bar that twists when subjected to force and provides elastic support through the torsional resistance of the torsion bar. The selection of the elastic component depends on the requirements of the specific application, such as load capacity, shock absorption characteristics and environmental conditions.

[0027] Please refer to Figure 4 And refer to Figure 3 When a predetermined weight is applied to the object supported by the container 110, such as when a user sits on a chair, the force acting on the elastic component 140 causes it to be compressed. When the elastic component 140 is compressed, the container 110 is pushed downward because the caster 130 is against the ground 10 and does not move in the vertical direction, resulting in a vertical displacement of the container 110 relative to the caster 130. This vertical displacement causes the bottom edge 114d of the container 110 to approach the ground 10. When the weight of the supported object increases, the compression of the elastic component 140 continues until the bottom edge 114d of the container 110 eventually comes into direct contact with the ground 10. When this happens, the contact between the bottom edge 114d and the ground 10 increases the friction between the caster device 100 and the ground 10. This increased friction makes the caster device 100 less likely to move or slide, providing stable and safe support for the supported object.

[0028] Next, please also refer to Figure 3 , Figure 5 ,and Figure 6 , Figure 5 A three-dimensional view of the upper container is shown. Figure 6 1, a perspective view of the lower container is depicted. In this embodiment, the container 110 includes an upper container 112 and a lower container 114. The side wall 114b of the lower container 114 and the side wall 112b of the upper container 112 each have an interlocking structure, respectively referred to herein as the second interlocking structure 114c and the first interlocking structure 112c. The first interlocking structure 112c and the second interlocking structure 114c allow the upper container 112 and the lower container 114 to be assembled together. Once assembled, a portion of the side wall 112b of the upper container 112 surrounds a portion of the side wall 114b of the lower container 114.

[0029] In this embodiment, the mounting bracket 120 is provided with a plurality of rails 124 (four in this embodiment) on both sides thereof, which cooperate with a corresponding plurality of guide grooves 114e in the container 110. This cooperation ensures smooth vertical sliding movement of the mounting bracket in the container. The rails 124 and the guide grooves 114e provide enhanced stability and prevent unnecessary lateral movement or rotation of the elastic component 140 during compression and rebound. In addition to the rails 124 and the guide grooves 114e, there are various optional mechanisms to achieve enhanced stability and prevent unnecessary movement or rotation of the elastic component 140 during compression and rebound, including but not limited to: ball bearing slides, telescopic slides or linear slides, and linear guides. Among them, the ball bearing slides use a set of ball bearings to perform smooth vertical movement between the mounting bracket 120 and the container 110, and the telescopic slides or linear slides have locking sections that extend and retract to maintain stability at the same time. In addition, linear guides are precision-engineered systems with guide rails and rolling elements to achieve stable motion along a single axis. In summary, a person skilled in the art can select a suitable vertical linear motion mechanism based on factors such as manufacturing cost, space constraints, and desired performance.

[0030] Next, please also refer to Figure 3 , Figure 5 , Figure 6 ,and Figure 7 , Figure 7 The embodiment of the rotary damper of the present invention is shown. In this embodiment, the caster device 100 further includes at least one rotary damper 150 (two in this embodiment), and the rotary damper 150 is mainly located between the side wall 114b of the lower half container 114 and the side wall 112b of the upper half container 112. Figure 3 As shown, the mounting bracket 120 is also equipped with at least one rack 122 (two in this embodiment). Figure 7 As shown, the rotation damper 150 includes a gear 152. The gear 152 is connected to the lower container 114 by a through hole 114g (eg, Figure 6 As shown), and cooperates with the rack 122 on the mounting bracket 120.

[0031] In this embodiment, the main function of the rotary shock absorber 150 is to provide a buffering and shock absorbing effect. For example, it helps prevent the following situations: the chair suddenly drops when people sit down, and suddenly rebounds when people leave the seat. This buffering and shock absorbing effect is achieved by the rotary shock absorber 150 cooperating with the rack 122 on the mounting bracket. In this embodiment, the rotary shock absorber 150 includes a main body 154, an input shaft 156 equipped with a gear 152, an output shaft (not shown) and a viscous fluid (not shown), wherein the output shaft and the viscous fluid are located inside the main body 154. When a force is applied to the object supported by the container 110 (for example: when a person sits on the chair), the input shaft 156 of the rotary shock absorber 150 rotates, and the input shaft 156 drives the output shaft to rotate, and the viscous fluid will produce resistance to the output shaft. This resistance produces a shock absorbing and buffering effect, which helps to control the movement of the object and prevent sudden drops or rebounds.

[0032] In this embodiment, the rotation damper 150 is placed in the groove 114f in the lower container 114, and the shape of the groove 114f conforms to the shape of the body 154 of the rotation damper 150. After the rotation damper 150 is placed in the groove 114f and the upper container 112 is combined with the lower container 114, the rotation damper 150 can be fixed between the side wall 114b of the lower container 114 and the side wall 112b of the upper container 112 without the need for additional screws or other fixings, thereby effectively reducing the number of required parts and making the appearance neater.

[0033] In addition to the rotary shock absorber 150 described above, other types of buffer mechanisms can be used to achieve similar effects. For example, gas springs or gas struts can be used as shock absorbing mechanisms. Gas springs use compressed gas (usually nitrogen) in a closed cylinder and a piston that moves according to the applied force. They provide controlled buffering, achieve smooth movement and prevent sudden drops or rebounds of the caster device 100. Another possible buffering mechanism is to use a friction buffer, which relies on the friction between two surfaces (in this embodiment, the side wall 114b of the lower half container 114 and the side wall of the mounting bracket 120) to produce a shock absorbing effect. Friction shock absorbers are generally composed of friction discs or plates in contact with a stationary surface. As the mounting bracket 120 moves, the friction between the surfaces dissipates energy, resulting in smooth and controlled movement. Each of these buffer mechanisms can be adapted and integrated into the caster device 100 of the present case to achieve the desired level of control and stability, ensuring smooth and safe operation while preventing sudden movement.

[0034] In this embodiment, a double-wheel swivel caster is used as an embodiment of the caster 130. Figure 8 , Figure 8The double wheel swivel caster of the present invention is shown in the following embodiment. The double wheel swivel caster comprises two wheels 132 mounted on a shared transverse axis ( Figure 8 The mounting bracket 120 is provided with a swivel caster 132 mounted on a vertical axis 136, and the lateral axis 136 is mounted on a mounting bracket 134, which is mounted below the mounting bracket 120 via a mounting axis 136. Compared with a single-wheel caster, a dual-wheel swivel caster provides better stability and load distribution. The dual-wheel swivel caster is mounted below the mounting bracket 120, allowing the wheel 132 to rotate freely about the vertical axis, allowing the wheel 132 to move smoothly and easily in any direction. The dual-wheel swivel caster design has several advantages, including increasing the ground contact area, improving stability, and reducing the risk of the caster 130 tipping over. In addition, the dual-wheel design improves load distribution and reduces pressure on each wheel 132 and the ground, thereby reducing wear on the wheel 132 and the floor surface. This design also enables the caster 130 to better traverse uneven surfaces or small obstacles, such as cracks or bumps in the ground, to ensure smooth and uninterrupted movement.

[0035] In addition, in this embodiment, the tread of the wheel 132 is also made of materials such as thermoplastic rubber or polyurethane. These materials have several advantages that can improve the overall performance of the wheel 132. First, the use of thermoplastic rubber or polyurethane to make the tire ensures that the wheel 132 produces very little noise when rolling. This feature is particularly important in environments where quiet operation is required, such as offices, hospitals, or libraries. Reducing noise can improve the ease of use of the caster device 100 while reducing interference with others. In addition, the wheel 132 made of thermoplastic rubber and polyurethane can provide better grip on different ground surfaces, including hardwood, tile, and carpet. This enhanced grip ensures that the caster device 100 remains stable and controlled during movement, reducing the possibility of slipping. Moreover, using thermoplastic rubber or polyurethane treads can also improve its durability and wear resistance, because these materials are known for their elasticity and will not degrade or lose performance characteristics under long-term use and heavy loads.

[0036] In addition, please also refer to Figure 1 , Figure 3 ,and Fig. 9 , Fig. 9Another application of the caster device of the present invention is shown. A person with ordinary knowledge in the art can install the caster device 100 at the four corners of a table 20 by fixing the screws 116, so that the table 20 can adapt to the uneven ground. This is because when the weight of the table 20 is concentrated on a certain caster device 100 due to the uneven ground, the elastic component 140 in the caster device 100 will be compressed, and this compression can allow the device to adapt to the uneven ground. For example, if there is a bulge on the ground 10, the elastic component 140 can be compressed to keep the surface of the table 20 flat. Of course, not only on the table, the caster device 100 can be installed on different objects (such as: chairs, mobile bookcases), and the same automatic balancing effect can be obtained.

[0037] In summary, the present invention proposes an innovative caster device having two upper and lower half containers, and equipped with an elastic component and a mounting bracket. Thereby, when a predetermined weight is applied to the supported object, better stability can be provided without manual activation or unlocking, and without using a larger or wider caster. In addition, the combination of the slide rail and the guide groove, and the use of the rotary shock absorber, further improve the stability of the caster device and the controllability during the compression and rebound of the elastic component. In addition, other embodiments of the present invention can also use various buffer mechanisms to achieve the same effect as the rotary shock absorber. In addition, in the above-mentioned embodiments, the design of the caster device does not require screws (but the present invention does not limit the use of screws or additional fixings), which is convenient for the assembler to easily assemble and disassemble. The material selection of the tread of the caster, such as thermoplastic rubber or polyurethane, ensures that the caster generates minimal noise when rolling on the ground. This is particularly important for environments that require quiet operation, such as offices, hospitals or libraries. In summary, the present invention presents an innovative and versatile caster device that is suitable for various applications, such as office desks and chairs, medical equipment, etc., which improves the comfort and satisfaction of users while ensuring optimal performance and reliability.

[0038] The invention is described above, but it is not intended to limit the scope of the patent rights claimed by the invention. Any changes or modifications made by those skilled in the art without departing from the spirit or scope of this patent shall be considered as equivalent changes or designs completed under the spirit disclosed by the invention and shall be included in the claims of the invention.

Claims

1. A caster device for supporting an object and suitable for being placed on a ground, the caster device being characterized in that: include: a container having a downward opening and a top plate; a mounting bracket disposed in the container and adapted to slide vertically in the container; at least one caster wheel fixed to one side of the mounting bracket and in contact with the ground; At least one elastic component is located on the other side of the mounting bracket and pressed against a bottom surface of the top plate of the container; When a predetermined weight is applied to the object supported by the container, the elastic component is compressed, and the bottom edge of the container contacts the ground, thereby increasing the friction between the caster device and the ground, making it difficult for the caster device to move.

2. The caster device according to claim 1, characterized in that: The elastic component is a spring.

3. The caster device according to claim 1, characterized in that: The container comprises an upper half container and a lower half container, a side wall of the lower half container and a side wall of the upper half container respectively have an interlocking structure, and the lower half container and the upper half container are assembled via the interlocking structure.

4. The caster device according to claim 3, characterized in that: It also includes at least one rotational shock absorber, which is located between the side wall of the lower half container and the side wall of the upper half container. The rotational shock absorber includes a gear that passes through a through hole located on the side wall of the lower half container and cooperates with a rack on the mounting bracket.

5. The caster device according to claim 1, characterized in that: The side wall of the mounting bracket includes a plurality of slide rails, and cooperates with a corresponding plurality of guide grooves in the container.

6. The caster device according to claim 1, characterized in that: The utility model also comprises a fixing screw, which is arranged on the container and is used for fixing the container to the bottom of the object.

7. The caster device according to claim 1, characterized in that: Also included is at least one buffer mechanism.

8. The caster device according to claim 7, characterized in that: The buffer mechanism is a rotary shock absorber.

9. The caster device according to claim 1, characterized in that: The caster is a double wheel swivel caster.

10. A castor assembly as claimed in claim 1 or claim 9, wherein the castor comprises a tread made of thermoplastic rubber or polyurethane.

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