Inner and outer bushing structure of telescopic table legs

Abstract

An inner and outer bushing structure for a telescopic table leg includes: an outer tube; an inner tube rotatably disposed inside the outer tube; an outer bushing fitted onto one end of the outer tube, with an outer guide pattern formed on its inner surface abutting against the outer wall of the inner tube; and an inner bushing fitted onto one end of the inner tube, with an inner guide pattern formed on its outer surface abutting against the inner wall of the outer tube.

Description

Inner and outer bushing structure of telescopic table legs Technical Field

[0001] This work relates to height-adjustable desks, specifically referring to an inner and outer bushing structure for telescopic desk legs that improves the smoothness of the desk legs' rotation. Prior Technology

[0002] Note that most furniture products on the market, such as height-adjustable desks, adjustable workbenches, and extendable coffee tables, are designed with height-adjustable or extendable legs to allow users to adjust the height according to their needs. To achieve stability and ease of operation, some traditional height-adjustable desk legs use an inner and outer tube telescopic structure, where the inner tube slides up and down relative to the outer tube and is positioned by a rotating or locking mechanism. While this type of rotating locking height-adjustable desk leg offers a degree of adjustment freedom, it still has its shortcomings, especially in that it is prone to jamming, uneven operation, or abnormal noise during actual rotation.

[0003] Further analysis reveals that most commonly used inner and outer tube structures are simply straight cylinders of metal or plastic, lacking a proper guiding and friction adjustment mechanism. When users rotate or adjust the inner tube, the contact surfaces of the inner and outer tubes may experience jamming, uneven rotation, or poor positioning due to dimensional errors, inconsistent surface roughness, or lack of lubrication. Furthermore, the absence of stable guiding elements between the inner and outer tubes can easily lead to eccentricity or wobbling, affecting not only the overall structural lifespan but also reducing the smoothness and accuracy of user adjustments. Moreover, without a buffer or guiding structure during rotation, repeated use can easily cause wear, deformation, or loosening of the positioning mechanism, severely impacting the durability and safety of the table leg structure. Therefore, providing a height-adjustable table leg that effectively solves the problem of uneven rotation is a pressing issue for manufacturers and researchers in this field. Summary of the Invention

[0004] The main purpose of this invention is to provide an inner and outer bushing structure for telescopic table legs, which can effectively improve the smoothness of table leg rotation.

[0005] To achieve the aforementioned creative purpose, this creation discloses an inner and outer bushing structure for a telescopic table leg, comprising: an outer tube; an inner tube rotatably disposed within the outer tube; an outer bushing fitted onto one end of the outer tube, with an outer guide pattern formed on its inner surface abutting against the outer wall of the inner tube; and an inner bushing fitted onto one end of the inner tube, with an inner guide pattern formed on its outer surface abutting against the inner wall of the outer tube.

[0006] In one embodiment, the outer liner is disposed at the top end of the outer tube, and the inner liner is disposed at the bottom end of the inner tube.

[0007] In one embodiment, the outer guide pattern is spirally wrapped around the inner surface of the outer bushing and forms an angle of less than 90 degrees with the axial direction of the outer bushing.

[0008] In one embodiment, the inner guide pattern is spirally arranged around the outer surface of the inner bushing and forms an angle of less than 90 degrees with the axial direction of the inner bushing.

[0009] In one embodiment, the outer tube has two oppositely arranged through holes on both sides; the outer bushing is provided with two oppositely arranged lugs corresponding to the two through holes, so that when the outer bushing is fitted onto one end of the outer tube, the two lugs extend into the two through holes.

[0010] In one embodiment, the top of the outer bushing has a stop portion, and the outer diameter of the stop portion is larger than the inner diameter of the outer tube, so that the stop portion abuts against the top of the outer tube.

[0011] In one embodiment, the bottom end of the inner tube has two opposing guide grooves extending along the axial direction of the inner tube; the inner bushing has two opposing ribs formed on the inner surface of the inner bushing, so that when the inner bushing is combined with the inner tube, the two ribs are respectively engaged with the two guide grooves.

[0012] In one embodiment, a fixing plate is provided axially inside the inner tube, and a cylindrical portion is provided in the center of the fixing plate extending axially along the inner tube; the bottom surface of the inner bushing has a through hole corresponding to the cylindrical portion of the fixing plate, for a locking fastener to pass through the through hole and extend into the cylindrical portion.

[0013] In one embodiment, the outer tube has a generally square cross-section, and the inner tube has a generally circular cross-section; the outer surface of the outer bushing is generally square and corresponds to the shape of the cross-section of the outer tube, and the inner surface of the outer bushing is generally circular and corresponds to the shape of the cross-section of the inner tube.

[0014] In one embodiment, the top of the outer bushing has a square-shaped abutment portion, and the side length of the abutment portion is greater than the side length of the inner wall of the outer tube, so that the abutment portion abuts against the top of the outer tube.

[0015] Based on the purpose and effect of this invention, the following are preferred embodiments, and detailed descriptions are provided with reference to the accompanying drawings. Simple Explanation of the Diagram

[0016] Figure 1 is an exploded view of a first preferred embodiment of the present invention. Figure 2 is a perspective view of the outer bushing of the first preferred embodiment of the present invention. Figure 3 is a perspective view of the inner bushing of the first preferred embodiment of the present invention. Figure 4 is a cross-sectional view of the first preferred embodiment of the present invention. Figure 5 is a partial cross-sectional view of the first preferred embodiment of the present invention, showing the outer bushing abutting against the outer wall of the inner tube. Figure 6 is a partial cross-sectional view of the first preferred embodiment of the present invention, showing the inner bushing abutting against the inner wall of the outer tube. Figure 7 is an exploded view of a second preferred embodiment of the present invention. Figure 8 is a perspective view of the outer bushing of the second preferred embodiment of the present invention. Figure 9 is a cross-sectional view of the second preferred embodiment of the present invention. Implementation

[0017] The following descriptions with reference to the various drawings are preferred embodiments of this invention. It should be understood that these drawings and descriptions are for illustrative purposes only and are not intended to limit this invention. Furthermore, the terms "upper" and "lower," "left" and "right," "front" and "back," "first" and "second," etc., used in the specification are used to clearly explain the relative positions between elements or mechanisms and are not intended to be limiting.

[0018] Please refer to Figures 1 to 6. The telescopic table leg provided in the first preferred embodiment of this invention mainly comprises: an outer tube 10, an inner tube 20, an outer bushing 30, and an inner bushing 40. Wherein:

[0019] In this embodiment, the outer tube 10 is a hollow circular tube with a generally circular cross-section. The top end of the outer tube 10 is an open end, and the bottom end is used to contact the ground. The outer tube 10 has two oppositely arranged through holes 11 on both sides adjacent to the top end.

[0020] In this embodiment, the inner tube 20 is a hollow circular tube with a generally circular cross-section, and its outer diameter is smaller than that of the outer tube 10. One end of the inner tube 20 is connected to the tabletop, and the other end is rotatably inserted into the outer tube 10. Specifically, the inner tube 20 is rotated to switch between unlocked and locked positions, and when switched to the unlocked position, the inner tube 20 can extend and retract relative to the outer tube 10, thereby adjusting the height of the table leg. The aforementioned rotation locking structure and lifting structure of the outer tube 10 and the inner tube 20 can be referenced from conventional lifting table legs, and are not the main technical features of this invention, so their details will not be elaborated here. The creative features of this invention are as follows:

[0021] The outer bushing 30 is detachably fitted onto one end of the outer tube 10. Its inner surface has at least one external guide groove 31 that abuts against the outer wall of the inner tube 20, providing guidance to improve the smoothness of rotation when the inner tube 20 rotates relative to the outer tube 10. Specifically, the outer bushing 30 is a hollow cylindrical component located at the top of the outer tube 10. The outer tube 10 has two opposing through holes 11 on both sides. The outer bushing 30 has two opposing lugs 32 extending radially outward, corresponding to the two through holes 11, so that when the outer bushing 30 is fitted onto one end of the outer tube 10, the two lugs 32 extend into the two through holes 11. Furthermore, the top of the outer bushing 30 has a stop portion 33, the outer diameter of which is larger than the inner diameter of the outer tube 10, so that the stop portion 33 abuts against the top of the outer tube 10.

[0022] In this embodiment, the outer guide pattern 31 of the outer bushing 30 is spirally wrapped around the inner surface of the outer bushing 30 and forms an angle of less than 90 degrees with the axial direction of the outer bushing 30. Thus, the outer guide pattern 31 is inclined relative to the axial direction of the inner tube 20, which helps the inner tube 20 to rotate along the outer guide pattern 31 of the outer bushing 30 during rotation.

[0023] The inner sleeve 40 is detachably fitted onto one end of the inner tube 20. Its outer surface has at least one inner guide groove 41 that abuts against the inner wall of the outer tube 10, providing guidance to improve the smoothness of rotation when the inner tube 20 rotates relative to the outer tube 10. Specifically, the inner sleeve 40 is a hollow cover located at the bottom end of the inner tube 20. The bottom end of the inner tube 20 has two opposing guide grooves 21 extending axially along the inner tube 20. The inner sleeve 40 has two opposing ribs 42 formed on its inner surface, so that when the inner sleeve 40 is engaged with the inner tube 20, the two ribs 42 respectively engage with the two guide grooves 21. The inner tube 20 has two semi-circular fixing pieces 22 axially inside, each with a hollow cylindrical portion 23 extending axially along the inner tube 20. The bottom surface of the inner bushing 40 has two through holes 43, which correspond to the two cylindrical portions 23 of the two fixing pieces 22, respectively, so that the two locking fasteners 50 can pass through the two through holes 43 and extend into the two cylindrical portions 23 to form axial fixation.

[0024] In this embodiment, the inner guide pattern 41 of the inner bushing 40 is spirally wrapped around the outer surface of the inner bushing 40 and forms an angle of less than 90 degrees with the axial direction of the inner bushing 40. Thus, the inner guide pattern 41 is inclined relative to the axial direction of the inner tube 20, which helps to allow the inner tube 20 to rotate along the inner guide pattern 41 of the inner bushing 40 during rotation.

[0025] Please refer to Figures 7 to 9. The lifting table legs provided in the second preferred embodiment of this invention have a structure similar to that of the first preferred embodiment. However, in this embodiment, the outer tube 10 is a square hollow tube with a generally square cross-section; while the inner tube 20 is still a hollow round tube. To match the shape of the outer tube 10, the outer bushing 30 disclosed in this embodiment has a generally square outer surface that corresponds to the shape of the cross-section of the outer tube 10. The top of the outer bushing 30 has a square abutment portion 33, and the side length of the abutment portion 33 is greater than the side length of the inner wall of the outer tube 10, so that the abutment portion 33 abuts against the top of the outer tube 10. Furthermore, the inner surface of the outer bushing 30 is generally circular and corresponds to the cross-sectional shape of the inner tube 20. Therefore, when the inner tube 20 is fitted inside the outer bushing 30, it can still rotate relative to the outer tube 10, and the outer guide lines 31 of the outer bushing 30 can still provide guidance for the inner tube 20. In other words, the shapes of the outer bushing 30 and the inner bushing 40 provided in this invention are not limited to the two shapes provided in this embodiment. Users can change the outer bushing 30 and the inner bushing 40 to corresponding shapes according to the shape, size, and diameter of the outer tube 10 and the inner tube 20. Thus, regardless of the shape of the inner bushing 40 and the structure of the outer bushing 30, they should not deviate from the application scope of this invention.

[0026] In summary, the inner and outer bushing structure of the telescopic table legs provided in this invention, through the internal structure of the outer bushing and inner bushing with guiding function, can effectively improve its rotation smoothness and positioning stability, thereby solving the problems of jamming, irregularity or abnormal noise that are easy to occur in conventional height-adjustable table legs during actual rotation operation.

[0027] The above are preferred embodiments and design drawings of this invention. However, the preferred embodiments and design drawings are merely illustrative examples and are not intended to limit the scope of the invention. Any implementation using equivalent technical means or within the scope of the claims covered by the "Plaintiff's Claims" below does not depart from the scope of this invention and is within the scope of the applicant's rights.

[0028] 10: External pipe 11: Through hole 20: Inner tube 21: Guide groove 22: Fixing plate 23: Cylindrical section 30: Outer bushing 31: External guide pattern 32: Earplate 33: Stopping part 40: Inner Liner 41 Internal Guide Pattern 42: Convex Rib 43: Through-hole 50: Locking fasteners

Claims

1. An inner and outer bushing structure for a telescopic table leg, comprising: an outer tube; an inner tube rotatably disposed within the outer tube; an outer bushing fitted onto one end of the outer tube, the inner surface of which has an outer guide pattern abutting against the outer wall of the inner tube; and an inner bushing fitted onto one end of the inner tube, the outer surface of which has an inner guide pattern abutting against the inner wall of the outer tube.

2. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the outer bushing is located at the top of the outer tube and the inner bushing is located at the bottom of the inner tube.

3. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the outer guide pattern is spirally wrapped around the inner surface of the outer bushing and forms an angle of less than 90 degrees with the axial direction of the outer bushing.

4. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the inner guide pattern is spirally wrapped around the outer surface of the inner bushing and forms an angle of less than 90 degrees with the axial direction of the inner bushing.

5. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the outer tube has two oppositely arranged through holes on both sides; the outer bushing is provided with two oppositely arranged lugs corresponding to the two through holes, such that when the outer bushing is fitted onto one end of the outer tube, the two lugs extend into the two through holes.

6. The inner and outer bushing structure of the telescopic table leg as described in claim 2, wherein the top of the outer bushing has a stop portion, and the outer diameter of the stop portion is larger than the inner diameter of the outer tube, so that the stop portion abuts against the top of the outer tube.

7. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the bottom end of the inner tube has two oppositely arranged guide grooves extending along the axial direction of the inner tube; the inner bushing has two oppositely arranged protruding ribs formed on the inner surface of the inner bushing, such that when the inner bushing is engaged with the inner tube, the two protruding ribs respectively engage with the two guide grooves.

8. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein a fixing piece is provided axially inside the inner tube, and a cylindrical portion extends axially along the inner tube from its center; the bottom surface of the inner bushing has a through hole corresponding to the cylindrical portion of the fixing piece, for a locking fastener to pass through the through hole and extend into the cylindrical portion.

9. The inner and outer bushing structure of the telescopic table leg as described in claim 1, wherein the cross-section of the outer tube is generally square and the cross-section of the inner tube is generally circular; the outer surface of the outer bushing is generally square and corresponds to the shape of the cross-section of the outer tube, and the inner surface of the outer bushing is generally circular and corresponds to the shape of the cross-section of the inner tube.

10. The inner and outer bushing structure of the telescopic table leg as described in claim 9, wherein the top of the outer bushing has a square abutment portion, and the side length of the abutment portion is greater than the side length of the inner wall of the outer tube, so that the abutment portion abuts against the top of the outer tube.

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