TWI870894B - Caster assembly - Google Patents

Abstract

A caster assembly is provided, comprising a container with a downward-facing opening and a top plate, and a mounting bracket that can vertically slide within the container. In addition, one or more wheels are attached to one side of the mounting bracket and make contact with the ground surface. On the other side of the mounting bracket, there is at least one elastic element that presses against the underside of the container's top plate. When a predetermined weight is applied to the object supported by the container, the elastic element is compressed, causing the bottom rim of the container to come into contact with the ground surface. This increases the friction between the caster assembly and the ground surface, making the caster less prone to movement. The elastic element may be, for example, a spring.

Description

Caster device

The present invention is a caster device, in particular a caster device designed to provide better stability when a predetermined weight is applied to the supported object.

Caster assemblies are widely used in various applications, such as office chairs, shopping carts, and mobile equipment, to facilitate easy movement of the objects they support. Traditionally, caster assemblies typically include a caster mounted on a bracket that is mounted and secured to the bottom of the object. Although these traditional caster assemblies allow for easy movement, they can also cause unintended movement or instability when a user applies weight to the supported object, such as when sitting in an office chair.

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

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.

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, or the use of larger or wider casters. Therefore, how to design such a caster device is a question worth considering by those with ordinary knowledge in the field.

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

Based on the above and other purposes, the present invention provides a caster device, which includes a container with a downward opening and the container 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 element 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 element 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 element is, for example, a spring.

In the caster device described above, 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.

In the caster device described above, at least one rotary shock absorber is further included. The rotary shock absorber is located between the side wall of the lower container and the side wall of the upper container. The rotary shock absorber includes a gear that passes through a through hole located on the side wall of the lower container and cooperates with the gear on the mounting bracket.

In the caster device described above, the two sides of the mounting bracket include slide rails that cooperate with corresponding multiple guide grooves in the container.

The caster device described above further includes a fixing screw, which is disposed on the container and is used to fix the container to the bottom of the object.

The caster device described above further includes at least one buffer mechanism, wherein the buffer mechanism may be the above-mentioned rotation shock absorber.

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

In the caster assembly described above, the caster comprises a tread made of thermoplastic rubber or polyurethane.

In order to make the above features and advantages of the present invention more clearly understood, the following is a detailed description of the preferred embodiment with the accompanying drawings.

10: Ground

20: Table

100: Caster device

110:Container

112: Upper container

112a: Top plate

112b, 114b: Side wall

112c: First interlocking structure

114: Lower container

114a: Open downwards

114c: Second interlocking structure

114d: bottom edge

114e: Guide groove

114f: Groove

114g:Through hole

116:Fixing screw

120: Mounting bracket

122: Tooth

124: Slide rail

126: Spring groove

130: Casters

140: Elastic element

150: Rotational shock absorber

152: Gear

Figures 1A and 1B show three-dimensional images of the caster device at different angles.

Figure 2 shows the internal structure of the caster device.

Figure 3 shows the changes of the caster device before and after force is applied.

Figure 4A shows a three-dimensional image of the upper container from the bottom.

Figure 4B shows a three-dimensional view of the lower half of the container.

FIG5 shows an embodiment of the rotational shock absorber of the present invention.

FIG6 shows an embodiment of the double-wheel swivel caster of the present invention.

FIG. 7 shows another application of the caster device of the present invention.

Please refer to FIG. 1A, FIG. 1B, FIG. 2, and FIG. 3 simultaneously, which show an embodiment of a caster device for supporting an object and suitable for being placed on the ground. Among them, FIG. 1A and FIG. 1B respectively show three-dimensional views of the caster device at different angles, FIG. 2 shows the internal structure of the caster device, and FIG. 3 shows the changes of the caster device before and after being subjected to force. 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 may be an office chair, an office desk, or a living room sofa, etc. By installing a plurality of caster devices 100 on the object, the object can be easily moved.

Please refer to FIG. 2 in particular. 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 suitable for vertical sliding in the container 110. In addition, the caster 130 is mounted on one side of the mounting bracket 120 and contacts the ground 10. In addition, in this embodiment, compared to the caster 130, the elastic element 140 is located on the other side of the mounting bracket 120 and is in contact with the ground 10. The upper part of the elastic element 140 is pressed against the lower side of the container top plate 112a. In addition, the mounting bracket 120 also includes two spring slots 126 for mounting springs (i.e., the elastic element 140).

In the present embodiment, the elastic element 140 is a spring, but a person skilled in the art may also select other elastic elements. For example, the elastic element includes an elastic block or pad made of an elastic material, such as rubber, silicone or polyurethane, which provides elastic support due to its inherent properties. In addition, the elastic element may also be a gel pad made of a deformable gel material to provide soft and elastic support, which helps to reduce vibration and impact. The elastic element may also be a flat, curved metal strip stacked and clamped together to form a leaf spring, which has a soft and strong support structure. Alternatively, the elastic element can also be a torsion bar, which is a long, cylindrical metal rod that twists when subjected to force, providing elastic support through the torsional resistance of the torsion bar. The choice of elastic element depends on the requirements of the specific application, such as load capacity, shock absorption characteristics and environmental conditions.

With particular reference to FIG. 3 and in conjunction with FIG. 2 , 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 element 140 causes it to be compressed. When the elastic element 140 is compressed, the container 110 is pushed downward because the casters 130 are against the ground 10 and do not move in the vertical direction, resulting in a vertical displacement of the container 110 relative to the casters 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 element 140 continues until the bottom edge 114d of the container 110 is finally in direct contact with the ground 10. When this occurs, the contact between the bottom edge 114d and the ground 10 increases the friction between the caster assembly 100 and the ground 10. This increased friction makes the caster assembly 100 less likely to move or slide, providing stable and secure support for the supported object.

Next, please refer to FIG. 2, FIG. 4A, and FIG. 4B simultaneously. FIG. 4A shows a perspective view of the upper container in the upward direction, and FIG. 4B shows a perspective view of the lower container. 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, which are respectively referred to 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 the assembly is completed, 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.

In this embodiment, the mounting bracket 120 is provided with a plurality of slide 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 a smooth vertical sliding movement of the mounting bracket in the container. The slide rails 124 and the guide grooves 114e provide enhanced stability, preventing unnecessary lateral movement or rotation of the elastic element 140 during compression and rebound. In addition to the slide 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 element 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 with ordinary knowledge in this field can select a suitable vertical linear motion mechanism based on factors such as manufacturing cost, space constraints, and desired performance.

Next, please refer to FIG. 2, FIG. 4A, FIG. 4B, and FIG. 5 simultaneously. FIG. 5 shows an embodiment of the rotary shock absorber of the present invention. In this embodiment, the caster device 100 further includes at least one rotary shock absorber 150 (two in this embodiment), and the rotary shock absorber 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. As shown in FIG. 2, the mounting bracket 120 is also equipped with at least one gear 122 (two in this embodiment). In addition, as shown in FIG. 5, the rotary shock absorber 150 includes a gear 152. This gear 152 passes through the through hole 114g located on the side wall 114b of the lower half container 114 (as shown in FIG. 4B ) and cooperates with the gear 122 on the mounting bracket 120.

In the present embodiment, the main function of the rotational shock absorber 150 is to provide a cushioning and shock absorbing effect. For example, it helps to prevent the following situations: the chair suddenly drops when people sit down, and suddenly bounces back when people leave the seat. This cushioning and shock absorbing effect is achieved by the rotational shock absorber 150 cooperating with the gear 122 on the mounting bracket. In the present embodiment, the rotational 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 force is applied to the object supported by the container 110 (for example, when a person sits on a 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 cushioning effect, which helps to control the movement of the object and prevent sudden drops or rebounds.

In this embodiment, the rotational shock absorber 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 main body 154 of the rotational shock absorber 150. After the rotational shock absorber 150 is placed in the groove 114f and the upper container 112 is combined with the lower container 114, the rotational shock absorber 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, so as to effectively reduce the number of parts required and make the appearance more neat.

In addition to the rotational shock absorber 150 described above, other types of shock absorber mechanisms can be used to achieve similar effects. For example, a gas spring or gas strut can be used as a shock absorbing mechanism. Gas springs utilize compressed gas (usually nitrogen) in a closed cylinder, and a piston that moves according to the applied force. They provide controlled shock absorption, achieve smooth movement and prevent sudden drops or rebounds of the caster device 100. Another possible shock absorber mechanism is to use a friction shock absorber, 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 typically composed of a friction disc or plate in contact with a stationary surface. As the mounting bracket 120 moves, the friction between the surfaces dissipates energy, resulting in smooth, controlled movement. Each of these cushioning mechanisms can be adapted and integrated into the caster assembly 100 of the present invention to achieve the desired level of control and stability, ensuring smooth and safe operation while preventing sudden movements.

In this embodiment, a double wheel swivel caster is used as an embodiment of the caster 130. Please refer to FIG6, which shows an embodiment of the double wheel swivel caster of the present invention. The double wheel swivel caster includes two wheels 132 mounted on a common cross shaft (not shown in FIG6), and the cross shaft is mounted on a mounting bracket 134, and the mounting bracket 134 is mounted below the mounting bracket 120 via a mounting shaft 136. Compared with a single wheel caster, the double 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 freely rotate about a 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, ensuring smooth and uninterrupted movement.

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 needs to be maintained, 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 assembly 100 maintains stability and control during movement, reducing the possibility of slipping. Furthermore, using a tread of thermoplastic rubber or polyurethane can also improve its durability and wear resistance, as these materials are known for their resilience and the fact that they will not degrade or lose performance characteristics under long-term use and heavy loads.

In addition, please refer to FIG. 1A, FIG. 2, and FIG. 7 simultaneously. FIG. 7 shows another application of the caster device of the present invention. A person skilled in the art can install the caster device 100 at the four corners of a table 20 by fixing 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 element 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 element 140 can be compressed, thereby keeping the surface of the table 20 flat. Of course, the caster device 100 can be installed not only on a table, but also on different objects (such as a chair, a mobile bookcase) to achieve the same automatic balancing effect.

In summary, the present invention provides an innovative caster device having two upper and lower half containers, and equipped with a resilient element 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 rotational shock absorber, further improve the stability of the caster device and the controllability during the compression and rebound process of the resilient element. In addition, other embodiments of the present invention can also use various buffer mechanisms to achieve the same effect as the rotational 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 produces minimal noise when rolling on the ground. This is especially important for environments that require quiet operation, such as offices, hospitals or libraries. In summary, the present invention demonstrates 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.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone with common knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of the patent application attached hereto.

100: Caster device

110:Container

114a: Open downwards

114d: bottom edge

114e: Guide groove

120: Mounting bracket

130: Casters

Claims (9)

A caster device is used to support an object and is suitable for being placed on a ground. The caster device comprises: a container having a downward opening and a top plate; a mounting bracket disposed in the container and suitable for vertically sliding in the container; at least one caster fixed to one side of the mounting bracket and in contact with the ground; at least one elastic element located on the other side of the mounting bracket and pressed against the mounting bracket; A bottom surface of the top plate of the container; and a fixing screw, which is arranged on the container and is used to fix the container to the bottom of the object; wherein, when a predetermined weight is applied to the object supported by the container, the elastic element is compressed, and the bottom edge of the container contacts the ground, thereby increasing the friction between the caster device and the ground, making the caster device difficult to move. A caster device as described in claim 1, wherein the elastic element is a spring. A caster device as described in claim 1, wherein the container includes an upper half container and a lower half container, and a side wall of the lower half container and a side wall of the upper half container each have an interlocking structure, and the lower half container and the upper half container are assembled through the interlocking structure. The caster device as described in claim 3 further includes at least one rotational shock absorber located between the side wall of the lower container and the side wall of the upper container, and the rotational shock absorber includes a gear that passes through a through hole located on the side wall of the lower container and cooperates with a gear on the mounting bracket. A caster device as described in claim 1, wherein the side wall of the mounting bracket includes a plurality of slide rails that cooperate with corresponding guide grooves in the container. The caster device as described in claim 1 further includes at least one buffer mechanism. A caster device as described in claim 6, wherein the buffer mechanism is a rotational shock absorber. A caster device as described in claim 1, wherein the caster is a double-wheel swivel caster. A caster device as described in claim 1 or claim 8, wherein the caster comprises a tread made of thermoplastic rubber or polyurethane.

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