Lifting column and electric standing desk

Abstract

A lifting column and an electric height-adjustable desk are disclosed, which relate to the fields of linear actuators and solve the problem of noise caused by excessive oscillation amplitude of the helical cable within the lifting column. The solution includes an actuator driving a telescoping tube assembly to telescope via a transmission assembly; a helical cable disposed on one side of and parallel with the transmission assembly; a first mounting base secured to one end of a middle tube; a second mounting base secured to one end of the inner tube; the transmission assembly includes a first telescopic part, a second telescopic part drivingly coupled to the first telescopic part and connected to the first mounting base, and a third telescopic part drivingly coupled to the second telescopic part and connected to the second mounting base; at least one of the first mounting base and the second mounting base defines a limiting hole for radially constraining the helical cable; the helical cable being routed through the limiting hole. The disclosure reduces noise.

Description

FIELD

[0001] The present disclosure relates to the field of linear actuators, and more particularly relates to a lifting column and an electric height-adjustable desk.BACKGROUND

[0002] A lifting column, as a component commonly used in linear actuator systems, is widely applied in equipment such as electric height-adjustable desks and electric height-adjustable beds. By way of example, an electric height-adjustable desk comprises a desktop, a support beam positioned beneath the desktop, and two lifting columns; a controller is mounted on the support beam and electrically connected to respective electric motors configured on both lifting columns to activate and control motor operation. Typically, a power interface is provided on the supporting beam for connection to the mains power supply. During vertical movement of the desktop, the cable connected to the power interface moves synchronously, resulting in cable entanglement around the height-adjustable desk.

[0003] To address the aforementioned issue, existing electric height-adjustable desks conceal the cables within the lifting columns. The cables extend and retract synchronously with the columns to continuously supply power to the powered device. For example, Chinese Patent Application No. CN108272227A discloses a height-adjustable desk featuring a concealed wiring configuration, comprising: a desktop; at least one desk leg connected to the desktop and incorporating a telescoping tube assembly; at least one drive module comprising an electric motor, a first lead screw, and a coupling sleeve, wherein the first lead screw and the coupling sleeve are housed within the telescoping tube assembly, the first lead screw is threadedly engaged with one end of the coupling sleeve and driven by the electric motor to screw in or out, thereby varying the length of the coupling sleeve; a control module comprising at least one electrical cable and a control interface, wherein the electrical cable is disposed within the telescoping tube assembly and helically wound around an outer circumferential surface of the coupling sleeve to deliver power to the at least one drive module; and a communication unit through which the control interface sends a control signal to the electric motor to activate the at least one drive module. In this conventional technology, since the electrical cable is helically wound around the outer circumferential surface of the coupling sleeve, as the telescoping tube assembly extends or retracts, the electrical cable is stretched or compressed along the outer circumferential surface of the coupling sleeve; particularly, when the helically wound cable is stretched, its diameter decreases, increasing friction against the telescoping tube assembly, accelerating insulation layer wear over time, potentially exposing the conductive core, causing electrical leakage, and posing significant safety hazards. Additionally, the requirement to manually wind the electrical cable around the coupling sleeve complicates assembly, maintenance, and replacement procedures.

[0004] Furthermore, Chinese Patent Application No. CN219069691U discloses a lifting column, in which the electrical cable is positioned along one inner side of the telescoping tube assembly and enclosed within a cable conduit, such that the electrical cable and the telescopic tube assembly are arranged side by side. However, in practice, the electrical cable's extendable length and inherent flexibility cause uncontrolled lateral vibration during a telescoping motion, resulting in collision with the telescoping tube assembly, with audible noise generated that degrades user experience.SUMMARY

[0005] A lifting column is provided to solve the problem of noise caused by excessive oscillation amplitude of the helical cable within the lifting column, thereby reducing noise.

[0006] The present disclosure adopts a technical solution below: a lifting column comprising: an actuator; a telescoping tube assembly including an inner tube having a second mounting base secured to one end thereof, a middle tube slidably and telescopically received over the inner tube and having a first mounting base secured to one end thereof, and an outer tube slidably and telescopically received over the middle tube; a transmission assembly coupled to the actuator and to the telescoping tube assembly, configured to drive extension and retraction of the telescoping tube assembly, and including a first telescopic part, a second telescopic part connected to the first mounting base and drivingly coupled to the first telescopic part, and a third telescopic part connected to the second mounting base and drivingly coupled to the second telescopic part; and a helical cable axially routed within the telescoping tube assembly and disposed on one side of and parallel with the transmission assembly, wherein at least one of the first mounting base and the second mounting base defines a limiting hole through which the helical cable is routed to effect radial constraint thereof.

[0007] With the technical solution, the present disclosure achieves the following benefits: at least one of the first mounting base and the second mounting base defines a limiting hole configured to radially constrain the helical cable. The radial displacement of the helical cable within the limiting hole is restricted by the inner wall of the limiting hole. Two ends of the helical cable are secured to opposing ends of the lifting column. By radially limiting an intermediate portion of the helical cable, the limiting hole effectively segments the helical cable into at least two longitudinal sections. This segmentation shortens the effective span of each section of the helical cable, thereby enhancing its structural rigidity with reduced deflection. During extension and retraction of the transmission assembly, the first mounting base and the second mounting base undergo relative axial displacement. Consequently, the limiting hole and the helical cable passing through the limiting hole move axially in synchronization. This dynamic configuration maintains the segmented state of the helical cable throughout the telescoping motion, confining lateral oscillation of the helical cable to a minimized range. As a result, collisions between the helical cable and the telescoping tube assembly are prevented, operational noise is significantly suppressed, and the lifting column delivers quieter, more reliable performance, thereby enhancing overall user experience. Additionally, since the helical cable merely passes through the limiting hole without being secured to the first mounting base or the second mounting base, no additional fastening or guiding components are required. The helical cable retains full freedom of telescoping motion. Consequently, the extension / retraction rate of the helical cable need not synchronize with the axial displacement speed of the limiting hole. This prevents inconsistent elongation and retraction across cable sections, ensuring uniform distribution of telescopic displacement along the entire cable length. Uniform tension variation across segments, such as gradual resistance increase during extension, avoids abrupt load fluctuations on the actuator, thereby enhancing the service life of both the helical cable and the actuator.

[0008] Furthermore, the radial constraint exerted by the limiting hole on the helical cable dynamically responds to the telescoping motion of the lifting column. Relative axial displacement occurs between the limiting hole and the helical cable. Even if unconfined portions of the helical cable exhibit lateral oscillation exceeding the constraint range of the limiting hole and momentarily contact the surrounding surface of the first mounting base or the second mounting base, the inherent flexibility of the helical cable ensures that the helical cable is forcibly constrained by the limiting hole with a reduced oscillation amplitude during passage through the limiting hole, thereby suppressing the overall lateral oscillation of the helical cable.

[0009] Furthermore, the first mounting base comprises a first mounting portion and a first limiting portion arranged horizontally side by side, the second telescopic part being secured to the first mounting portion, and the limiting hole being defined in the first limiting portion. With this technical solution, the limiting hole defined in the first limiting portion ensures the helical cable traversing therethrough remains side by side with the transmission assembly, preventing mutual interference between the helical cable and the transmission assembly during the axial telescoping motion of the lifting column, thereby facilitating smooth operation and assembly of the helical cable and enhancing assembly efficiency of the lifting column.

[0010] Furthermore, the second telescopic part comprises a second lead screw and a first transmission nut, the second lead screw being mounted to the first mounting portion via a fixed bearing and engaging with the third telescopic part, and the first transmission nut being secured to the first mounting portion and engaging with the first telescopic part. With this technical solution, due to engagement between the fixed bearing and the second lead screw, the second lead screw remains firmly fixed to the first mounting portion while rotating synchronously with the first lead screw, minimizing friction and ensuring transmission stability and efficiency, thereby enhancing smooth operation and stability of the lifting column. The engagement between the second lead screw and the third telescopic part ensures that the third telescopic part telescopes linearly along the second lead screw.

[0011] The first lead screw rotates to induce relative displacement between the first transmission nut and the first telescopic part; since the first transmission nut is secured to the first mounting base, rotation of the first telescopic part drives linear motion of the first mounting base; here, the relative displacement of the first mounting base relative to the first telescopic part is denoted as L 1 . Concurrently, rotation of the first telescopic part drives the second lead screw to rotate synchronously therewith; rotation of the second lead screw induces relative displacement between the second transmission nut and the second lead screw; since the second transmission nut is connected to the second mounting base, the second lead screw is displaced relative to the second mounting base; here, the relative displacement of the second lead screw relative to the second mounting base is denoted as L 2 . The second lead screw and the first transmission nut are rotatably coupled in an axially constrained configuration, permitting relative rotation while preventing axial movement between the second lead screw and the first transmission nut. Consequently, the second lead screw maintains a fixed axial position relative to the first mounting base. Therefore, the cumulative relative displacement between the second mounting base and the first lead screw during rotation of the first lead screw equals L 1 + L 2 . This structural configuration yields a significantly greater displacement of the second mounting base and thus the inner tube per revolution of the first lead screw compared to conventional single-nut configurations. As a result, the inner tube achieves faster axial travel within a given time interval, enhancing the overall telescoping speed of the lifting column. Additionally, since the helical cable is routed merely through the limiting hole without being secured to either the first mounting base or the second mounting base, the helical cable remains free from tensile stress or strain during motion while ensuring smooth, uninterrupted operation of the lifting column during rapid telescoping cycles.

[0012] Furthermore, the first mounting base is assembled from a first portion and a second portion, the first portion and the second portion being configured to clamp and retain the fixed bearing and the first transmission nut, and complementary recesses being formed in the first portion and the second portion to define the limiting hole upon assembly. With this technical solution, the modular configuration of the first mounting base facilitates mounting of the fixed bearing and the first transmission nut onto the first mounting base, thereby simplifying manufacturing, assembly, disassembly, and maintenance while offering higher flexibility. The clamping arrangement between the first portion and the second portion ensures stable retention of the fixed bearing and the first transmission nut within the first mounting base, enabling the first transmission nut to reliably drive telescoping motion of the first mounting base and the second lead screw secured therein during its linear telescoping motion along the first lead screw, thereby ensuring telescoping stability of the lifting column and effectively preventing any looseness or vibration of the fixed bearing and the first transmission nut from affecting the telescoping motion of the lifting column. Both the first portion and the second portion are configured with complementary recesses so that they can be formed identically, allowing them to be fabricated with a single mold. During assembly, one portion is simply inverted and aligned with the other portion, eliminating the need for differentiation. This configuration reduces manufacturing costs and enhances assembly efficiency.

[0013] Furthermore, the respective outer peripheries of the first mounting portion and the first limiting portion conform to and interface with the inner wall of the middle tube. This configuration secures a reliable connection of the first mounting portion and the first limiting portion to the middle tube, preventing any positional looseness of the first mounting base relative to the middle tube and ensuring that the first mounting base can reliably drive the middle tube to telescope during the axial telescoping motion of the lifting column.

[0014] Furthermore, the second mounting base comprises a second mounting portion and a second limiting portion arranged side by side, the third telescopic part being secured to the second mounting portion, and the limiting hole being defined in the second limiting portion. This arrangement maintains the helical cable routed through the second limiting portion and the transmission assembly in side-by-side arrangement, preventing mutual interference between the helical cable and the transmission assembly during axial telescoping motion, simplifying installation of the helical cable, and enhancing assembly efficiency of the lifting column. Additionally, the limiting hole constrains oscillation of the helical cable to minimize noise caused by collision with the telescoping tube assembly. Since the third telescopic part is secured to the second mounting portion, axial telescoping motion of the second mounting portion drives synchronous telescoping motion of the third telescopic part, thereby improving telescoping efficiency.

[0015] Furthermore, the second mounting base is integrally formed, with the limiting hole extending longitudinally through the second limiting portion, the outer periphery of the second mounting base conforming to and interfacing with the inner wall of the inner tube. This integral formation of the second mounting base simplifies the manufacturing process, reduces component count, facilitates rapid assembly, enhances production efficiency, and reduces time-related production costs. The conformingly interfacing between the outer periphery of the second mounting base and the inner wall of the inner tube secures a reliable connection between the second mounting base and the inner tube, preventing any positional looseness of the second mounting base relative to the inner tube and ensuring that the second mounting base can reliably drive the inner tube to telescope during the axial telescoping motion of the lifting column.

[0016] The first mounting base and the second mounting base each define a limiting hole for radially constraining the helical cable, the limiting hole in the first mounting base and the limiting hole in the second mounting base being configured to radially constrain the helical cable at two axially spaced positions during upward extension of the lifting column, with the axial distance between the two positions progressively increasing. In this technical solution, the limiting holes formed in both mounting bases are configured to partition the helical cable into three shorter segments, implementing segmented radial constraint. This reduces the lengths of the cable segments spanning: from the upper end of the helical cable to the first mounting base, between the first and second mounting bases, and from the second mounting base to the lower end of the helical cable. Consequently, oscillation of the helical cable is more effectively suppressed, enhancing the amplitude-damping effect of the limiting holes, and further minimizing operational noise.

[0017] During upward extension of the lifting column, the first mounting base translates along the first lead screw, elevating the middle tube. Concurrently, the second lead screw rotates synchronously with the first lead screw and engages the second transmission nut housed within the second mounting base, driving the second mounting base to translate along the second lead screw and thereby elevating the inner tube. As the spacing between the limiting hole in the first mounting base and the limiting hole in the second mounting base gradually increases, the helical cable extends synchronously with the telescoping tube assembly maintaining three constrained segments throughout the telescoping motion, thereby reducing oscillation amplitude.

[0018] Furthermore, an upper end of the helical cable is connected to the actuator, a lower end of the helical cable is connected to a junction box mounted at the bottom of the lifting column, and in the extended state of the lifting column, the limiting hole in the first mounting base is positioned closer to the upper end of the helical cable and the limiting hole in the second mounting base is positioned closer to the lower end of the helical cable. According to this technical solution, the junction box incorporates a first power interface electrically connected to the lower end of the helical cable. The junction box conceals the electrical connection joint within its interior, isolating the terminals of both the helical cable and the first power interface from the transmission assembly and the telescoping tube assembly. This prevents contact between these terminals and the transmission assembly or telescoping tube assembly, eliminating risks of electrical leakage, arcing, or sparking, thereby enhancing operational safety. The limiting hole in the first mounting base is positioned closer to the upper end of the helical cable, and the limiting hole of the second mounting base is positioned closer to its lower end. The upper and lower connection points of the helical cable serve as inherent constraint points of the helical cable. Together with the limiting hole in the first mounting base and the limiting hole in the second mounting base, four sequential radial constraint points are established from top to bottom: (1) the connection interface between the helical cable and the actuator; (2) the limiting hole on the first mounting base; (3) the limiting hole on the second mounting base; and (4) the connection interface between the helical cable and the junction box. This configuration partitions the entire helical cable into three segments of more balanced lengths, ensuring uniform radial constraint distribution.

[0019] Furthermore, a limiting sleeve is disposed within the inner tube and surrounds the helical cable, the limiting sleeve isolating the portion of the helical cable positioned within the inner tube from the transmission assembly. Given the relatively small cross-sectional area of the inner tube, the limiting sleeve radially constrains the helical cable, thereby directly preventing oscillation-induced contact between the helical cable and the inner tube during telescoping motion. Any potential contact between the limiting sleeve and the helical cable results in minimal impact due to the short radial clearance therebetween, reducing the likelihood of significant noise generation. Additionally, the inner tube, positioned radially outside the limiting sleeve, blocks noise generated by such contact. Under the radial constraint provided by the limiting sleeve, the oscillation amplitude of the helical cable is further reduced, contributing to overall noise reduction.

[0020] Furthermore, the first mounting base and the second mounting base each define a limiting hole, and in the retracted state of the lifting column, the passage formed by the limiting sleeve, the limiting hole in the first mounting base, and the limiting hole in the second mounting base align and interconnect to form a continuous passage enclosing at least the spiral portion of the helical cable. According to this technical solution, in the retracted state of the lifting column, the passage formed by the limiting sleeve, the limiting hole in the first mounting base, and the limiting hole in the second mounting base align and interconnect to form a continuous passage. This arrangement effectively receives and shields the helical cable from potential collisions or contact with the telescoping tube assembly during handling.

[0021] Furthermore, a grease reservoir is disposed within the inner tube, positioned below the transmission assembly, and fixedly connected to the limiting sleeve or the inner tube. With this technical solution, during high-speed or prolonged operation of the lifting column, elevated temperatures increase the fluidity of the grease on the transmission assembly, causing the grease to drip downward. The grease reservoir collects the dripping grease and prevents its leakage to the exterior of the lifting column.

[0022] Furthermore, the outer tube, the middle tube, and the inner tube are arranged sequentially from top to bottom, the actuator is mounted on top of the outer tube, and the first telescopic part is drivingly coupled to the output shaft of the actuator. According to this technical solution, in the extended state of the lifting column, the middle tube resides between the outer tube and the inner tube; in the retracted state of the lifting column, the middle tube is received within the outer tube and the inner tube within the middle tube, yielding a compact configuration that facilitates transportation and installation while enhancing structural stability, strength, and load-bearing capability. The actuator is embodied as a housing with an electric motor and a reducer disposed therein, the electric motor and the reducer being configured to deliver the torque required for telescoping motion of the transmission assembly. The torque flows from the actuator to the first telescopic part, then to the second telescopic part, and finally to the third telescopic part, ensuring efficient torque transmission to drive extension and retraction of the telescoping tube assembly. Unlike the conventional upright mounting architecture of the telescoping tube assembly which uses a transmission sleeve for outward torque transmission, as disclosed in Chinese Patent Application No. CN108272227A, the inverted mounting architecture of the present disclosure simplifies the structure of the transmission assembly and meets the spatial constraints for the side-by-side arrangement of the helical cable and the transmission assembly.

[0023] Furthermore, the first telescopic part comprises a first lead screw, the second telescopic part comprises a second lead screw and a first transmission nut, the third telescopic part comprises a second transmission nut, the first lead screw passes through the first transmission nut and extends into the second lead screw, the first lead screw engages the first transmission nut for torque transmission, the second lead screw is non-rotationally coupled to the first lead screw for synchronous rotation therewith and passes through the second transmission nut for torque transmission, the first transmission nut is secured to the first mounting base, and the second transmission nut is secured to the second mounting base. According to this technical solution, with the outer tube fixed as a reference frame, the actuator drives rotation of the first lead screw. The first transmission nut, engaged with the first lead screw, converts the rotational motion of the first lead screw into linear telescoping motion of the first transmission nut along the first lead screw, thereby driving the middle tube (to which the first mounting base is mounted) to extend and retract. That is, cooperative engagement between the first lead screw and the first transmission nut actuates telescoping motion of the middle tube. While the first lead screw is rotating, the second lead screw, which is non-rotationally coupled to the first lead screw, rotates synchronously therewith, inducing linear telescoping motion of the second transmission nut along the second lead screw. The second transmission nut, in turn, drives the inner tube (to which the second mounting base is mounted) to extend and retract. Thus, upon actuation of the actuator, the middle tube and inner tube extend and retract simultaneously, achieving axial telescoping motion of the lifting column. This configuration accelerates the axial telescoping motion, minimizes user waiting time, and enhances user experience. With the inner tube fixed as a reference frame, the actuator drives rotation of the first lead screw. The second lead screw, non-rotationally coupled to the first lead screw, rotates synchronously therewith and undergoes linear telescoping motion within the second transmission nut. Being secured to the first mounting base, the second lead screw thereby drives telescoping motion of the middle tube to which the first mounting base is mounted. Concurrently, the first lead screw, cooperating with the first transmission nut, undergoes linear telescoping motion within the first transmission nut and drives the outer tube to extend and retract. Thus, upon actuation of the actuator, the middle tube and the outer tube extend and retract simultaneously, achieving axial telescoping motion of the lifting column.

[0024] The present disclosure further provides an electric height-adjustable desk, comprising a desktop, a controller, and a lifting column, the desktop being fixed to the top of the lifting column, wherein the lifting column is defined in any of the embodiments described supra, and the controller is electrically connected to the helical cable of the lifting column. Electrical devices may be placed on the desktop. Since the helical cable is fully concealed within the lifting column, there is no risk of entanglement between the helical cable and power cords of the electrical devices placed on the desktop during height adjustment. This eliminates pulling forces on both the device power cords and the helical cable. The electric height-adjustable desk produces negligible noise within the lifting column during operation, thereby enhancing user experience.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Hereinafter, the present disclosure will be further described with reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram of a lifting column in a retracted state according to the present disclosure. Fig. 2 is a schematic diagram of the lifting column in an extended state. Fig. 3 is a cross-sectional view of the lifting column in its retracted state. Fig. 4 is a cross-sectional view of the lifting column in its extended state. Fig. 5 is a first schematic diagram of an internal structure of the lifting column. Fig. 6 is a cross-sectional view of the internal structure of the lifting column. Fig. 7 is a second schematic diagram of the internal structure of the lifting column. Fig. 8 is an enlarged view of part A in Fig. 7. Fig. 9 is a structural diagram of a first mounting base. Fig. 10 is a structural diagram of a second portion of the first mounting base. Fig. 11 is a top view of the first mounting base. Fig. 12 is a schematic diagram of fitting between the first mounting base and the transmission assembly. Fig. 13 is a structural diagram of a second mounting base. Fig. 14 is a cross-sectional view of the second mounting base. Fig. 15 is a schematic diagram of a junction box. Fig. 16 is a structural diagram of a limiting sleeve. DETAILED DESCRIPTION OF EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the disclosure more apparent, the technical solutions in the embodiments of the disclosure will be described in a clear and comprehensive manner with reference to the accompanying drawings; it is apparent that the example embodiments described herein are only part of the embodiments of the disclosure, not all of them.

[0027] The terms such as "first," "second," "third," and "fourth" (if present) referred to in the specification and claims of the disclosure are used for distinguishing like objects, not necessarily used for describing a specific sequence or priority. Even if a technical feature is referred to with "second," it does not necessary indicate that there surely exists a "first" such feature. It would be understood that the terms "comprise" and "have," as well as any of their variants, intend for a non-exclusive inclusion. It would be understood that in the disclosure, the term "plurality" refers to two or more. The term "and / or" only describes an association relationship of associated objects, which indicates that there may exist three relationships, e.g., X and / or Y may indicate three circumstances: X individually, or both X and Y together, or Y individually. The character " / " generally indicates a relationship of "or" between the former and latter associated objects. The term "comprising X, Y, and Z" or "comprising X, Y, Z" refers to comprising all of X, Y, and Z; the term "comprising X, Y, or Z" refers to comprising one of X, Y, and Z; the term "comprising X, Y and / or Z" refers to comply any one, or any two, or three of X, Y, and Z.

[0028] Hereinafter, the technical solution of the disclosure will be described in detail through specific embodiments. The specific embodiments described infra may be combined or replaced with each other dependent on actual circumstances, and same or similar concepts or processes may be omitted in some embodiments.First Embodiment

[0029] As illustrated in Figs. 1 to 16, the present disclosure provides a lifting column, comprising an actuator 1, a transmission assembly, a telescoping tube assembly and a helical cable 4 axially routed through the telescoping tube assembly. The actuator 1 actuates extension and retraction of the telescoping tube assembly via the transmission assembly. The helical cable 4 is disposed on one side of and parallel with the transmission assembly. The telescoping tube assembly comprises an inner tube 31, a middle tube 32 slidably and telescopically received over the inner tube 31, and an outer tube 33 slidably and telescopically received over the middle tube 32. A first mounting base 34 is secured to one end of the middle tube 32, and a second mounting base 35 is secured to one end of the inner tube 31. The transmission assembly comprises a first telescopic part 21, a second telescopic part 22 connected to the first mounting base 34, and a third telescopic part 23 connected to the second mounting base 35, wherein the second telescopic part 22 is drivingly coupled to the first telescopic part 21, and the third telescopic part 23 is drivingly coupled to the second telescopic part 22. A limiting hole 36 is defined in the first mounting base 34, or the second mounting base 35, or both, and is configured to radially constrain the helical cable 4, the helical cable 4 being routed through the limiting hole 36.

[0030] In this embodiment, the helical cable 4 is disposed on one side of and parallel with the transmission assembly. The helical cable 4 may deliver power to the transmission assembly. The helical cable 4 is formed with multiple helical windings. When the transmission assembly extends, a pitch of the helical cable 4 increases, causing the helical cable 4 to elongate axially. Conversely, when the transmission assembly retracts, the pitch decreases, causing the electric cable 4 to shorten. Therefore, the helical cable 4 extends and retracts synchronously with the transmission assembly. This configuration allows the helical cable 4 to be housed internally within the telescoping tube assembly, enabling internal routing of the helical cable 4 and eliminating external exposure that could cause clutter or pose tripping hazards for users passing by.

[0031] At least one of the first mounting base 34 and the second mounting base 35 defines a limiting hole 36 configured to radially constrain the helical cable 4. The limiting hole 36 may be formed in either the first mounting base 34 or the second mounting base 35. The radial displacement of the helical cable 4 within the limiting hole 36 is constrained by the inner wall of the limiting hole 36. Two ends of the helical cable 4 are secured to opposing ends of the lifting column. By radially constrain the intermediate portion of the helical cable 4, the limiting hole 36 effectively segments the helical cable 4 into at least two longitudinal sections. This segmentation shortens the effective span of each section of the helical cable 4, thereby enhancing its structural rigidity with reduced deflection. During extension and retraction of the transmission assembly, the first mounting base 34 and the second mounting base 35 undergo relative axial displacement. Consequently, the limiting hole 36 and the helical cable 4 routed through the limiting hole 36 move axially in synchronization. This dynamic configuration maintains the segmented state of the helical cable 4 throughout the telescoping motion, confining lateral oscillation of the helical cable 4 to a minimized range. As a result, collisions between the helical cable 4 and the telescoping tube assembly are prevented, operational noise is significantly suppressed, and the lifting column delivers quieter, more reliable performance, thereby enhancing overall user experience.

[0032] Additionally, since the helical cable 4 is merely routed through the limiting hole 36 without being secured to the first mounting base 34 or the second mounting base 35, no additional fastening or guiding components are required. The helical cable 4 retains full freedom of telescoping motion. Consequently, the extension / retraction rate of the helical cable 4 need not synchronize with the axial displacement speed of the limiting hole 36. This prevents inconsistent elongation and retraction across cable segments, ensuring uniform distribution of telescopic displacement along the entire cable length. Uniform tension variation across segments, such as gradual resistance increase during extension, avoids abrupt load fluctuations on the actuator 1, thereby enhancing the service life of both the helical cable 4 and the actuator 1.

[0033] Furthermore, the radial constraint exerted by the limiting hole 36 on the helical cable 4 dynamically responds to the telescoping motion of the lifting column. Relative axial displacement occurs between the limiting hole 36 and the helical cable 4. Even if unconfined portions of the helical cable 4 exhibit lateral oscillation exceeding the constraint range of the limiting hole 36 and momentarily contact the surrounding surface of the first mounting base 34 or the second mounting base 35, the inherent flexibility of the helical cable 4 ensures that the helical cable 4 is forcibly constrained by the limiting hole 36 with a reduced oscillation amplitude during passage through the limiting hole 36, thereby suppressing the overall lateral oscillation of the helical cable 4.

[0034] In one embodiment, the inner wall of the limiting hole 36 tapers inwardly from both open ends toward the central region. The wall surface may be configured as a curved surface or an inclined surface, providing guidance for the helical cable 4. The enlarged openings of the limiting hole 36 facilitate entry of the helical cable 4, while the converging profile forcibly constrains the helical cable 4 toward the narrowest section of the limiting hole 36, further minimizing the lateral oscillation amplitude of the helical cable 4.

[0035] In conventional technologies, the cable is typically helically wound around the periphery of the transmission assembly and directly connected between two fixed points at the upper and lower ends of the lifting column. In contrast, the present application positions the helical cable 4 on one side of and parallel with the transmission assembly and subjects it to radial constraint via the limiting hole 36. This arrangement decouples axial telescoping motion between the helical cable 4 and the transmission assembly. Moreover, compared to the conventionally unconstrained cable configuration, the helical cable 4 is radially constrained at its intermediate portion, which significantly reduces the lateral oscillation amplitude during telescoping motion. This minimizes collision risk with the telescoping tube assembly and associated noise generation. Even if incidental contact occurs, only negligible noise is produced due to the restrained oscillation amplitude.

[0036] In the present disclosure, a single continuous helical cable 4 is routed through the limiting hole 36 to impose radial constraint. Without altering the overall telescopic length of the helical cable 4, this configuration reduces the lateral oscillation of the helical cable 4 within a confined spatial region, effectively reducing its oscillation amplitude. While exemplified in a three-section lifting column, the solution is equally applicable to multi-section configurations comprising three or more telescoping sections.

[0037] As illustrated in Figs. 1 to 8, in one embodiment, the outer tube 33, the middle tube 32, and the inner tube 31 are arranged sequentially from top to bottom. The actuator 1 is mounted on top of the outer tube 33, with the first telescopic part 21 coupled to the output shaft of the actuator 1. In the extended state, the middle tube 32 resides between the outer tube 33 and inner tube 31; in the retracted state, the middle tube 32 is received within the outer tube 33 and the inner tube 31 within the middle tube 32, yielding a compact configuration that facilitates transportation and installation while enhancing structural stability, strength, and load-bearing capability. The actuator 1 is embodied as a housing with an electric motor and a reducer disposed therein, the electric motor and the reducer being configured to deliver the torque required for telescoping motion of the transmission assembly. The torque flows from the actuator 1 to the first telescopic part 21, then to the second telescopic part 22, and finally to the third telescopic part 23, ensuring efficient torque transmission to drive extension / retraction of the telescoping tube assembly. Unlike the conventional upright mounting architecture of the telescoping tube assembly which uses a transmission sleeve for outward torque transmission, as disclosed in Chinese Patent Application No. CN108272227A, the inverted mounting architecture of the present disclosure simplifies the structure of the transmission assembly and meets the spatial constraints for the side-by-side arrangement of the helical cable 4 and the transmission assembly.

[0038] Specifically, the first telescopic part 21 comprises a first lead screw 211; the second telescopic part 22 comprises a second lead screw 221 and a first transmission nut 222; the third telescopic part 23 comprises a second transmission nut 231. The first lead screw 211 is routed through the first transmission nut 222 and extends into the second lead screw 221. The first lead screw 211 engages the first transmission nut 222 for torque transmission. The second lead screw 221 is non-rotationally coupled to the first lead screw 211 to rotate synchronously therewith and passes through the second transmission nut 231 for torque transmission. The first transmission nut 222 is secured to the first mounting base 34, and the second transmission nut 231 is secured to the second mounting base 35.

[0039] With the outer tube fixed as a reference frame, the actuator 1 drives rotation of the first lead screw 211. The first transmission nut 222, engaged with the first lead screw 211, converts the rotational motion of the first lead screw 211 into linear telescoping motion of the first transmission nut 222 along the first lead screw 211, thereby driving the middle tube 32 (to which the first mounting base 34 is mounted) to extend and retract. That is, cooperative engagement between the first lead screw 211 and the first transmission nut 222 actuates telescoping motion of the middle tube 32. While the first lead screw 211 is rotating, the second lead screw 221, which is non-rotationally coupled to the first lead screw 211, rotates synchronously therewith, inducing linear telescoping motion of the second transmission nut 231 along the second lead screw 221. The second transmission nut 231, in turn, drives the inner tube 31 (to which the second mounting base 35 is mounted) to extend and retract. Thus, upon actuation of the actuator 1, the middle tube 32 and inner tube 31 extend and retract simultaneously, achieving axial telescoping motion of the lifting column. This configuration accelerates the axial telescoping motion, minimizes user waiting time, and enhances user experience.

[0040] With the inner tube fixed as a reference frame, the actuator 1 drives rotation of the first lead screw 211. The second lead screw 221, non-rotationally coupled to the first lead screw 211, rotates synchronously therewith and undergoes linear telescoping motion within the second transmission nut 231. Being secured to the first mounting base 34, the second lead screw 221 thereby drives telescoping motion of the middle tube 32 to which the first mounting base 34 is mounted. Concurrently, the first lead screw 211, cooperating with the first transmission nut 222, undergoes linear telescoping motion within the first transmission nut 222 and drives the outer tube 33 to extend and retract. Thus, upon actuation of the actuator 1, the middle tube 32 and the outer tube 33 extend and retract simultaneously, achieving axial telescoping motion of the lifting column.

[0041] The first lead screw 211 rotates to induce relative displacement between the first transmission nut 222 and the first lead screw 211; since the first transmission nut 222 is secured to the first mounting base 34, rotation of the first lead screw 211 drives linear motion of the first mounting base 34; here, the relative displacement of the first mounting base 34 relative to the first lead screw 211 is denoted as L 1 . Concurrently, rotation of the first lead screw 211 drives the second lead screw 221 to rotate synchronously therewith; rotation of the second lead screw 221 induces relative displacement between the second transmission nut 231 and the second lead screw 221; since the second transmission nut 231 is connected to the second mounting base 35, the second lead screw 221 is displaced relative to the second mounting base 35; here, the relative displacement of the second lead screw 221 relative to the second mounting base 35 is denoted as L 2 . The second lead screw 221 and the first transmission nut 222 are rotatably coupled in an axially constrained configuration, permitting relative rotation while preventing axial movement between the second lead screw 221 and the first transmission nut 222. Consequently, the second lead screw 221 maintains a fixed axial position relative to the first mounting base 34. Therefore, the cumulative relative displacement between the second mounting base 35 and the first lead screw 211 during rotation of the first lead screw 211 equals L 1 + L 2 . This structural configuration yields a significantly greater displacement of the second mounting base 35 and thus the inner tube 31 per revolution of the first lead screw 211 compared to conventional single-nut configurations. As a result, the inner tube 31 achieves faster axial travel within a given time interval, enhancing the overall telescoping speed of the lifting column. Additionally, since the helical cable 4 is routed merely through the limiting hole 36 without being secured to either the first mounting base 34 or the second mounting base 35, the helical cable 4 remains free from tensile stress or strain during motion while ensuring smooth, uninterrupted operation of the lifting column during rapid telescoping cycles.

[0042] As illustrated in Figs. 8 to 12, when the limiting hole 36 is formed in the first mounting base 34, to facilitate assembly of the helical cable 4, in one embodiment, the first mounting base 34 comprises a first mounting portion 341 and a first limiting portion 342 arranged side by side. The second telescopic part 22 is secured to the first mounting portion 341, while the limiting hole 36 is defined in the first limiting portion 342. The limiting hole 36 defined in the first limiting portion 342 ensures the helical cable 4 traversing therethrough remains side by side with the transmission assembly, preventing mutual interference between the helical cable 4 and the transmission assembly during the axial telescoping motion of the lifting column, thereby facilitating smooth operation and assembly of the helical cable 4 and enhancing assembly efficiency of the lifting column.

[0043] The second telescopic part 22 is secured to the first mounting base 34 via the first mounting portion 341; consequently, the second telescopic part 22 moves axially with the first mounting base 34. The first mounting base 34 is mounted on the middle tube 32; consequently, the second telescopic part 22 extends and retracts synchronously with the middle tube 32.

[0044] Specifically, as illustrated in Fig. 8, the second lead screw 221 is mounted on the first mounting portion 341 via a fixed bearing 223 and engages the third telescopic part 23. The first transmission nut 222 is secured to the first mounting portion 341 and engages the first telescopic part 21. The fixed bearing 223 engages the second lead screw 221 such that the second lead screw 221 remains firmly fixed to the first mounting portion 341 while rotating synchronously with the first lead screw 211, minimizing friction and ensuring transmission stability and efficiency, thereby enhancing smooth operation and stability of the lifting column. The engagement between the second lead screw 221 and the third telescopic part 23 ensures that the third telescopic part 23 telescopes linearly along the second lead screw 221.

[0045] To facilitate secure mounting of the fixed bearing 223 and the first transmission nut 222 on the first mounting base 34, in one embodiment, the first mounting base 34 is assembled from a first portion 343 and a second portion 344. The first portion 343 and the second portion 344 are configured to clamp and retain the fixed bearing 223 and the first transmission nut 222. Complementary recesses are formed in both the first and second portions 343, 344 to define the limiting hole 36 upon assembly. This modular configuration of the first mounting base 34 facilitates mounting of the fixed bearing 223 and the first transmission nut 222 onto the first mounting base 34, thereby simplifying manufacturing, assembly, disassembly, and maintenance while offering a higher flexibility. The clamping arrangement between the first portion 343 and the second portion 344 ensures stable retention of the fixed bearing 223 and the first transmission nut 222 within the first mounting base 34, enabling the first transmission nut 222 to reliably drive telescoping motion of the first mounting base 34 and the second lead screw 221 secured therein during its linear telescoping motion along the first lead screw 211, thereby ensuring telescoping stability of the lifting column and effectively preventing any looseness or vibration of the fixed bearing 223 and the first transmission nut 222 from affecting the telescoping motion of the lifting column.

[0046] As illustrated in Figs. 9 to 11, both the first portion 343 and the second portion 344 are configured with complementary recesses so that they can be formed identically, allowing them to be fabricated with a single mold. During assembly, one portion is simply inverted and aligned with the other portion, eliminating the need for differentiation. This configuration reduces manufacturing costs and enhances assembly efficiency.

[0047] To securely mount the first mounting base 34 to the middle tube 32, in one embodiment, respective outer peripheries of the first mounting portion 341 and the first limiting portion 342 conform to and interface with the inner wall of the middle tube 32. This configuration secures a reliable connection of the first mounting portion 341 and the first limiting portion 342 to the middle tube 32, preventing any positional looseness of the first mounting base 34 relative to the middle tube and ensuring that the first mounting base 34 can reliably drive the middle tube to telescope during the axial telescoping motion of the lifting column.

[0048] As illustrated in Figs. 13 to 14, when the limiting hole 36 is formed in the second mounting base 35, in one embodiment, the second mounting base 35 comprises a second mounting portion 351 and a second limiting portion 352 arranged horizontally side by side. The third telescopic part 23 is secured to the second mounting portion 351, and the limiting hole 36 is defined in the second limiting portion 352. This arrangement maintains the helical cable 4 routed through the second limiting portion 352 and the transmission assembly in side-by-side arrangement, preventing mutual interference between the helical cable 4 and the transmission assembly during axial telescoping motion, simplifying installation of the helical cable 4, and enhancing assembly efficiency of the lifting column. Additionally, the limiting hole 36 constrains oscillation of the helical cable 4 to minimize noise caused by collision with the telescoping tube assembly. Since the third telescopic part 23 is secured to the second mounting portion 351, axial telescoping motion of the second mounting portion 351 drives synchronous telescoping motion of the third telescopic part 23, thereby improving telescoping efficiency.

[0049] In one embodiment, to secure the second mounting base 35 to the inner tube 31, the second mounting base 35 is integrally formed, with the limiting hole 36 extending longitudinally through the second limiting portion 352; the outer periphery of the second mounting base 35 conforms to and interfaces with the inner wall of the inner tube 31. During the axial telescoping motion of the lifting column, the second mounting base 35 translates linearly with the second transmission nut 231 along the second lead screw 221; this configuration ensures a reliable connection between the second mounting base 35 and the inner tube 31, enabling the second mounting base 35 to drive the inner tube 31 to telescope stably in synchronization.

[0050] Specifically, the integral formation of the second mounting base 35 simplifies the manufacturing process, reduces component count, facilitates rapid assembly, enhances production efficiency, and reduces time-related production costs. Alternatively, the second mounting base 35 may also be provided in a modular configuration. Its specific structure is adjustable according to actual requirements.

[0051] Specifically, the first mounting base 34 and the second mounting base 35 may be configured as rectangular blocks, where the first mounting portion 341 and the first limiting portion 342 are arranged along the longitudinal direction of the rectangular block (i.e., the first mounting base 34), while the second mounting portion 351 and the second limiting portion 352 are arranged along the longitudinal direction of the rectangular block (i.e., the second mounting base 35). The first mounting portion 341, the first limiting portion 342, the second mounting portion 351, and the second limiting portion 352 may be configured as circular holes. A notch defined in the longitudinal edge of the first mounting base 34 is configured to secure mounting of the first mounting base 34 within the telescoping tube assembly, and a protruding grid structure formed on a lateral side of the first mounting base 34 is configured for snap-fit engagement with the inner wall of the middle tube 32. Connection holes and mating posts are provided on the interfacing surfaces of both the first portion 343 and the second portion 344, wherein the connection holes are configured to mate with the mating posts to enable plug-in assembly of the first portion and the second portion.

[0052] The second transmission nut 231 is secured within the second mounting portion 351, snap-fit interfaces are provided on the lateral corners of the second mounting base 35 for snap-fit engagement with the inner tube 31, thereby securing the second mounting base 35 to the inner tube 31.Second Embodiment

[0053] As illustrated in Figs. 2 to 16, in this embodiment, both the first mounting base 34 and the second mounting base 35 are formed with a respective limiting hole 36 for radially limiting the helical cable 4. During upward extension of the lifting column, the limiting hole 36 in the first mounting base 34 and the limiting hole 36 in the second mounting base 35 radially constrain the helical cable 4 at two axially spaced positions, with the axial distance between the two positions progressively increasing. The limiting holes 36 formed in both mounting bases 34, 35 are configured to partition the helical cable 4 into three shorter segments, implementing segmented radial constraint. This reduces the lengths of the cable segments spanning: from the upper end of the helical cable 4 to the first mounting base 34, between the first and second mounting bases 34 and 35, and from the second mounting base 35 to the lower end of the helical cable 4. Consequently, oscillation of the helical cable 4 is more effectively suppressed, enhancing the amplitude-damping effect of the limiting holes 36, and further minimizing operational noise.

[0054] During upward extension of the lifting column, the first mounting base 34 translates along the first lead screw 211, elevating the middle tube 32. Concurrently, the second lead screw 221 rotates synchronously with the first lead screw 211 and engages the second transmission nut 231 housed within the second mounting base 35, driving the second mounting base 35 to translate along the second lead screw 221 and thereby elevating the inner tube 31. As the spacing between the limiting hole 36 in the first mounting base 34 and the limiting hole 36 in the second mounting base 35 gradually increases, the helical cable 4 extends synchronously with the telescoping tube assembly maintaining three constrained segments throughout the telescoping motion, thereby reducing oscillation amplitude.

[0055] As illustrated in Figs. 4 to 6 and Fig. 15, to further suppress cable oscillation, in one embodiment, the upper end of the helical cable 4 connects to the actuator 1, while the lower end thereof connects to a junction box 41 mounted at the bottom of the lifting column. In the extended state of the lifting column, the limiting hole 36 in the first mounting base 34 is positioned closer to the upper end of the helical cable 4, and the limiting hole 36 of the second mounting base 35 is positioned closer to its lower end. The upper and lower connection points of the helical cable 4 serve as inherent constraint points of the helical cable 4. Together with the limiting hole 36 in the first mounting base 34 and the limiting hole 36 in the second mounting base 35, four sequential radial constraint points are established from top to bottom: (1) the connection interface between the helical cable 4 and the actuator 1; (2) the limiting hole 36 on the first mounting base 34; (3) the limiting hole 36 on the second mounting base 35; and (4) the connection interface between the helical cable 4 and the junction box 41. This configuration partitions the entire helical cable 4 into three segments of more balanced lengths, ensuring uniform radial constraint distribution.

[0056] The junction box 41 incorporates a first power interface electrically connected to the lower end of the helical cable 4. The junction box 41 conceals the electrical connection joint within its interior, isolating the terminals of both the helical cable 4 and the first power interface from the transmission assembly and the telescoping tube assembly. This prevents contact between these terminals and the transmission assembly or telescoping tube assembly, eliminating risks of electrical leakage, arcing, or sparking, thereby enhancing operational safety. For a lifting column vertically installed, by arranging the limiting hole 36 in the first mounting base 34 closer to the upper end of the helical cable and the limiting hole 36 in the second mounting base 35 closer to the lower end of the helical cable, the inner tube 31 remains secured to the ground during extension of the lifting column, the middle tube 32 extends upward relative to the inner tube 31, and the outer tube 33 extends upward relative to the middle tube 32, which facilitates direct mechanical coupling between the transmission assembly and telescoping tube assembly, simplifying the structure of the transmission assembly.

[0057] Notably, the position of the first power interface remains stationary relative to the ground regardless of telescoping motion, preventing displacement of the mains power cord connected thereto.

[0058] As illustrated in Fig. 15, the junction box 41 comprises a housing 412 and a terminal chamber 413 formed therein. The electrical connection joint between the helical cable 4 and the first power interface is fully concealed within the terminal chamber 413, wherein the helical cable 4 and the first power interface are electrically connected inside the terminal chamber 413 to ensure concealment of the electrical connection joint.

[0059] To prevent detachment of the helical cable 4 from the actuator 1 or the junction box 41 during telescoping motion of the lifting column, a first cable clip is secured to the upper end of the helical cable 4, and a second cable clip 43 is secured to the lower end. Both cable clips share an identical fundamental structure; for clarity, the second cable clip 43 is described herein. The second cable clip 43 defines an opening 431 through which the lower end of the helical cable 4 is snap-fitted and secured. Similarly, the upper end is snap-fitted into the first cable clip. This configuration fixes both ends of the helical cable 4, with the helical structure of the cable enabling axial extension and retraction to maintain continuous electrical connection.

[0060] Specifically, the helical cable 4 features a positioning protrusion 44 projecting radially outward. The second cable clip 43 is correspondingly provided with a retention groove 432. During snap-fitting of the helical cable 4 into the second cable clip 43, the positioning protrusion 44 engages the retention groove 432 to axially position the cable along the telescoping direction of the transmission assembly, with the opposing sidewalls of the retention groove 432 abutting the positioning protrusion 44 in the axial direction to maintain engagement throughout the telescoping motion and ensure uninterrupted power supply to the powered device.

[0061] Alternatively, the positioning protrusion 44 may also be provided on the cable clip, while the retention groove 432 is provided on the helical cable 4.

[0062] The second cable clip 43 further defines a retention hole 433 communicating with the opening 431. The helical cable 4 is radially snap-fitted through the opening 431 into the retention hole 433, minimizing mechanical stress on the cable and facilitating disassembly. The inner wall of the opening 431 incorporates a stop protrusion configured to radially abut and retain the helical cable 4 within the retention hole 433, thereby preventing radial displacement of the helical cable 4 during telescoping motion of the transmission assembly and avoiding separation from the second cable clip 43.

[0063] In one embodiment, the second cable clip 43 is mounted on the junction box 41. The housing 412 of the junction box 41 incorporates a first mounting hole 414 for mounting the second cable clip 43, the first mounting hole 414 communicating with the terminal chamber 413. After snap-fitting to the second cable clip 43, the helical cable 4 can extend into the terminal chamber 413 through the first mounting hole 414, facilitating connection between the helical cable 4 and the junction box 41. Alternatively, the cable clip may be integrally formed with the housing 412.

[0064] Additionally, the housing 412 further features a second mounting hole 415 for mounting the first power interface, which also communicates with the terminal chamber 413. One side of the first power interface extending into the terminal chamber 413 is provided with a terminal post for electrical connection with the helical cable 4, while the other side thereof is provided with a socket 416. The first power interface is mounted at the second mounting hole 415 so that the terminal post may extend into the terminal chamber 413 through the second mounting hole 415. When the first power interface is securely mounted on the junction box, the terminal post is retained within the terminal chamber 413, preventing the electrical connection joint of the helical cable 4 with the terminal post from contacting the transmission assembly or the telescoping tube assembly.

[0065] The junction box 41 is disposed at the bottom of the inner tube 31. The lifting column further comprises a mounting plate 5, which is fixedly connected to the junction box 41, the transmission assembly, and the telescoping tube assembly. This mounting plate 5 connects parts of the transmission assembly and the telescoping tube assembly, allowing the transmission assembly to drive telescoping motion of the telescoping tube assembly. It also secures the junction box 41 to the telescoping tube assembly, reducing the number of components required for assembling the junction box 41 and thereby simplifying the assembly process.

[0066] As illustrated in Figs. 3 to 6 and Fig. 16, during telescoping motion of the telescoping tube assembly, the inner tube 31 and the middle tube 32 telescope relative to the outer tube 33. Due to the smaller inner diameter of the inner tube 31 compared to that of the outer tube 33, the helical cable 4 is more prone to contact the inner wall of the inner tube 31. To further minimize noise generated by such contact, a limiting sleeve 311 is disposed within the inner tube 31 and surrounds the helical cable 4. The limiting sleeve 311 isolates the helical cable 4 positioned within the inner tube 31 from the transmission assembly. Given the relatively small cross-sectional area of the inner tube 31, the limiting sleeve 311 radially constrains the helical cable 4, thereby directly preventing oscillation-induced contact between the helical cable 4 and the inner tube 31 during telescoping motion. Any potential contact between the limiting sleeve 311 and the helical cable 4 results in minimal impact due to the short radial clearance therebetween, reducing the likelihood of significant noise generation. Additionally, the inner tube 31 positioned radially outside the limiting sleeve 311 blocks noise generated by such contact. Under the radial constraint provided by the limiting sleeve 311, the oscillation amplitude of the helical cable 4 is further reduced, contributing to overall noise reduction.

[0067] The limiting sleeve 311 is positioned on one side of and parallel with the transmission assembly, preventing entanglement between the helical cable 4 and the transmission assembly that could otherwise compromise operational stability of the lifting column. This arrangement facilitates assembly of the helical cable 4 and simplifies overall assembly of the lifting column. By partially limiting the helical cable 4, the limiting sleeve 311 further reduces contact between the helical cable 4 and the inner wall of the inner tube 31, thereby preventing the helical cable 4 from oscillating and directly contacting the inner wall of the inner tube 31 during telescoping motion. The limiting sleeve 311 contributes to noise reduction by minimizing noise generated from contact between the helical cable 4 and the sleeve. Furthermore, under the radial constraint provided by the limiting sleeve 311, the oscillation amplitude of the helical cable 4 is reduced, not only within the constrained section but also in portions of the helical cable 4 extending axially beyond the limiting sleeve 311, thereby further reducing noise.

[0068] The limiting sleeve 311 may be fabricated from a material exhibiting vibration-damping and noise-reducing properties, such as rubber. Additionally, the limiting sleeve 311 may be configured as a telescopic sleeve that extends and retracts synchronously with the telescoping motion of the transmission assembly. Upon extension of the transmission assembly, the limiting sleeve 311, which is telescopic, correspondingly extends, thereby enhancing radial constraint coverage on the helical cable 4 and preventing contact between the helical cable 4 and the transmission assembly even as the helical cable 4 elongates.

[0069] As illustrated in Figs. 5 and 6, in one embodiment, both the first mounting base 34 and the second mounting base 35 define respective limiting holes 36. In the retracted state of the lifting column, the passage formed by the limiting sleeve 311, the limiting hole 36 in the first mounting base 34, and the limiting hole 36 in the second mounting base 35 align and interconnect to form a continuous passage, thereby enclosing at least the spiral portion of the helical cable 4. This arrangement effectively receives and shields the helical cable 4 from potential collisions or contact with the telescoping tube assembly during handling.

[0070] To prevent grease from dripping to the bottom of the lifting column and leaking to the exterior, in one embodiment, a grease reservoir 312 is disposed within the inner tube 31, positioned below the transmission assembly and fixedly connected to the limiting sleeve 311. Specifically, the grease reservoir 312 is arranged on a lateral side of and parallel with the limiting sleeve 311; the two components may be integrally formed or pre-assembled as a single unit. This side-by-side configuration enables simultaneous installation of both components, reducing assembly steps and facilitating disassembly for maintenance. During high-speed or prolonged operation of the lifting column, elevated temperatures increase the fluidity of the grease on the transmission assembly, causing the grease to drip downward. The grease reservoir 312 collects the dripping grease and prevents its leakage to the exterior of the lifting column.

[0071] It is understood that the grease reservoir 312 can also be independently installed and fixed within the inner tube 31, not limited to the above description.

[0072] Other details not described herein may refer to First Embodiment.Third Embodiment

[0073] The present disclosure further provides an electric height-adjustable desk, comprising a desktop, a controller, and a lifting column. The desktop is fixed to the top of the lifting column, wherein the lifting column is the lifting column described in the aforementioned embodiments, and the controller is electrically connected to the helical cable 4.

[0074] Electrical devices may be placed on the desktop. Since the helical cable 4 is fully concealed within the lifting column, there is no risk of entanglement between the helical cable 4 and power cords of the electrical devices placed on the desktop during height adjustment. This eliminates pulling forces on both the device power cords and the helical cable 4.

[0075] Protected by the junction box 41, the lifting column is free from electrical leakage, thereby preventing electric shock hazards to users. Additionally, insufficient voltage supply to the actuator 1 via the helical cable 4 caused by leakage is avoided, ensuring reliable power delivery and smooth, uninterrupted height adjustment of the desktop.

[0076] In one embodiment based on the foregoing embodiments, the actuator 1 is further provided with a second power interface. This second power interface may be electrically connected to the controller of the electric height-adjustable desk, to an external circuit, or to another lifting column.

[0077] The above-described embodiments are merely preferred embodiments of the present disclosure. All other obvious embodiments obtained by a person skilled in the art based on the embodiments disclosed herein shall fall within the scope of the appended claims

Claims

1. A lifting column comprising: an actuator; a telescoping tube assembly including an inner tube having a second mounting base secured to one end thereof, a middle tube slidably and telescopically received over the inner tube and having a first mounting base secured to one end thereof, and an outer tube slidably and telescopically received over the middle tube; a transmission assembly coupled to the actuator and to the telescoping tube assembly, configured to drive extension and retraction of the telescoping tube assembly, and including a first telescopic part, a second telescopic part connected to the first mounting base and drivingly coupled to the first telescopic part, and a third telescopic part connected to the second mounting base and drivingly coupled to the second telescopic part; and a helical cable axially routed within the telescoping tube assembly and disposed on one side of and parallel with the transmission assembly, wherein at least one of the first mounting base and the second mounting base defines a limiting hole through which the helical cable is routed to effect radial constraint thereof.

2. The lifting column of claim 1, wherein the first mounting base comprises a first mounting portion and a first limiting portion arranged horizontally side by side, the second telescopic part being secured to the first mounting portion, and the limiting hole being defined in the first limiting portion.

3. The lifting column of claim 2, wherein the second telescopic part comprises a second lead screw and a first transmission nut, the second lead screw being mounted to the first mounting portion via a fixed bearing and engaging with the third telescopic part, and the first transmission nut being secured to the first mounting portion and engaging with the first telescopic part.

4. The lifting column of claim 3, wherein the first mounting base is assembled from a first portion and a second portion, the first portion and the second portion being configured to clamp and retain the fixed bearing and the first transmission nut, and complementary recesses being formed in the first portion and the second portion to define the limiting hole upon assembly.

5. The lifting column of claim 2, wherein the respective outer peripheries of the first mounting portion and the first limiting portion conform to and interface with the inner wall of the middle tube.

6. The lifting column of claim 1, wherein the second mounting base comprises a second mounting portion and a second limiting portion arranged horizontally side by side, the third telescopic part being secured to the second mounting portion, and the limiting hole being defined in the second limiting portion.

7. The lifting column of claim 6, wherein the second mounting base is integrally formed, with the limiting hole extending longitudinally through the second limiting portion, the outer periphery of the second mounting base conforming to and interfacing with the inner wall of the inner tube.

8. The lifting column of claim 1, wherein the first mounting base and the second mounting base each define a limiting hole for radially constraining the helical cable, the limiting hole in the first mounting base and the limiting hole in the second mounting base being configured to radially constrain the helical cable at two axially spaced positions during upward extension of the lifting column, with the axial distance between the two positions progressively increasing.

9. The lifting column of claim 8, wherein an upper end of the helical cable is connected to the actuator, a lower end of the helical cable is connected to a junction box mounted at the bottom of the lifting column, and in the extended state of the lifting column, the limiting hole in the first mounting base is positioned closer to the upper end of the helical cable and the limiting hole in the second mounting base is positioned closer to the lower end of the helical cable.

10. The lifting column of claim 1, wherein a limiting sleeve is disposed within the inner tube and surrounds the helical cable, the limiting sleeve isolating the portion of the helical cable positioned within the inner tube from the transmission assembly.

11. The lifting column of claim 10, wherein the first mounting base and the second mounting base each define a limiting hole, and in the retracted state of the lifting column, the passage formed by the limiting sleeve, the limiting hole in the first mounting base, and the limiting hole in the second mounting base align and interconnect to form a continuous passage enclosing at least the spiral portion of the helical cable.

12. The lifting column of claim 10, wherein a grease reservoir is disposed within the inner tube, positioned below the transmission assembly, and fixedly connected to the limiting sleeve or the inner tube.

13. The lifting column of claim 1, wherein the outer tube, the middle tube, and the inner tube are arranged sequentially from top to bottom, the actuator is mounted on top of the outer tube, and the first telescopic part is drivingly coupled to the output shaft of the actuator.

14. The lifting column of claim 13, wherein the first telescopic part comprises a first lead screw, the second telescopic part comprises a second lead screw and a first transmission nut, the third telescopic part comprises a second transmission nut, the first lead screw passes through the first transmission nut and extends into the second lead screw, the first lead screw engages the first transmission nut for torque transmission, the second lead screw is non-rotationally coupled to the first lead screw for synchronous rotation therewith and passes through the second transmission nut for torque transmission, the first transmission nut is secured to the first mounting base, and the second transmission nut is secured to the second mounting base.

15. An electric height-adjustable desk, comprising a desktop, a controller, and a lifting column, the desktop being fixed to the top of the lifting column, wherein the lifting column is defined according to any one of claims 1 to 14, and the controller is electrically connected to the helical cable of the lifting column.

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