Patent Description:
In a lifting column of a lift mechanism such as a lift table or a lift chair available in current markets, an actuating device is always disposed at an upper end of a transmission assembly and directly fixed to the bottom surface of a lifted platform to thereby implement coupling between the lifting column and the lifted platform. However, an electric motor in the actuating device easily causes vibration during operating, while the vibration is easily transmitted to the lifted platform, causing the lifted platform to vibrate, which affects use experience.

<CIT> discloses a linear actuator for height adjustment of a table. The linear actuator comprises a telescopic housing and a spindle system arranged in the telescopic housing, which are driven by a drive arranged in a drive housing. The drive housing is arranged on a telescopic part of the telescopic housing. SUMMARY Embodiments of the present disclosure provide a lifting column transmission assembly that enables a smooth transmission, and a lifting column.

In an aspect of the present disclosure, there is provided a transmission assembly for a lifting column that includes an inner tube, comprising: an exteriorly threaded hollow spindle, a transmission screw disposed in the hollow spindle, a sleeve fitted over the hollow spindle, a guide tube limited in the sleeve, and an actuating device actuating the guide tube to rotate, the guide tube and the hollow spindle being synchronously rotatable and being axially expandable and contractable relative to each other; the transmission screw and the hollow spindle being synchronously rotatable and being axially expandable and contractable relative to each other; wherein the actuating device is disposed in the inner tube and securely mounted to an upper end of the sleeve; and a lower end of the sleeve is securely connected with a first transmission nut that is thread-fitted with the hollow spindle, and the first transmission nut is securely coupled to the inner tube, the upper end of the sleeve being movably disposed.

In an embodiment, a top plate is disposed at an upper end of the inner tube, with a gap provided between the actuating device and the top plate; or, a flexible top plate is provided at the upper end of the inner tube, without a gap provided between the actuating device and the flexible top plate.

In an embodiment, a gap is provided between the actuating device and the inner tube.

In an embodiment, the transmission assembly further comprises a positioning block, a positioning slot is provided on a sidewall of the first transmission nut, and a positioning hole is provided at a lower end of the inner tube; wherein the positioning block sequentially passes through the positioning hole and the positioning slot such that positions of the first transmission nut and the inner tube are fixed in the axial direction.

In an embodiment, the actuating device comprises a motor, a gearbox casing, and a deceleration mechanism disposed in the gearbox casing, wherein the deceleration mechanism comprises a sun gear coupled to an output shaft of the motor, a bevel gear planet carrier transmission-fitted with the sun gear, and a spur gear planet carrier fitted with an output end of the bevel gear planet carrier.

In an embodiment, the upper end of the sleeve and the actuating device are coupled via a bolt; or, the upper end of the sleeve and the actuating device are coupled via a bayonet connection.

In an embodiment, the lower end of the sleeve and the first transmission nut are coupled via a bolt; or, the lower end of the sleeve and the first transmission nut are coupled via a bayonet connection.

In another aspect of the present disclosure, there is further provided a lifting column, comprising: a transmission assembly, and an inner tube and an outer tube which are sequentially fitted from inside to outside, wherein the transmission assembly refers to the transmission assembly for a lifting column recited in any of the technical solutions above.

In an embodiment, a lower end of a hollow spindle is provided with a second transmission nut thread-fitted with the transmission screw, and a locking structure limiting the second transmission nut from rotation is provided outside the second transmission nut, the locking structure being disposed in the outer tube and movably fitted with the outer tube.

In an embodiment, the transmission assembly further comprises an intermediate tube disposed between the inner tube and the outer tube, the lower end of the hollow spindle is provided with a second transmission nut thread-fitted with the transmission screw, a locking structure limiting the second transmission nut from rotation is provided outside the second transmission nut, the locking structure being securely coupled to a lower end of the intermediate tube.

Herein, "the upper end of the sleeve is movably disposed" means that the upper end of the sleeve is unfixed, floating in the inner tube.

With the above technical solutions, the present disclosure offers the following advantages:.

Hereinafter, the present disclosure will be further illustrated with reference to the accompanying drawings:.

Reference Numerals:
<NUM>. transmission screw; <NUM>. second transmission part; <NUM>. hollow spindle; <NUM>. first transmission part; <NUM>. guide tube; <NUM>. sleeve; <NUM>. actuating device; <NUM>. motor; <NUM>. gearbox casing; <NUM>. gearbox outer case; <NUM>. gearbox cap; <NUM>. sun gear; <NUM>. bevel gear planet carrier; <NUM>. spur gear planet carrier; <NUM>. spline bushing; <NUM>. second transmission nut; <NUM>. locking structure; <NUM>. first locking block; <NUM>. second locking block; <NUM>. first transmission nut; <NUM>. positioning slot; <NUM>. inner tube; <NUM>. top plate; <NUM>. positioning block; <NUM>. outer tube; <NUM>. base plate; <NUM>. intermediate tube.

Hereinafter, the present disclosure will be described in further detail through preferred embodiments with reference to the accompanying drawings. It is understood that the oriental or positional relationships indicated by the terms "upper," "lower," "left," "right," "longitudinal," "transverse," "inner," "outer," "vertical," "horizontal," "top" and "bottom," etc. are oriental and positional relationships only based on the drawings, which are intended only for facilitating or simplifying description of the present disclosure, not for indicating or implying that the devices/elements have to possess those specific orientations or have to be configured and operated with those specific orientations; therefore, they should not be understood as limitations to the present disclosure.

As shown in <FIG>, a transmission assembly for a lifting column is provided, the lifting column includes an inner tube <NUM>, the transmission assembly comprising: an exteriorly threaded hollow spindle <NUM>, a transmission screw <NUM> disposed in the hollow spindle <NUM>, a sleeve <NUM> fitted over the hollow spindle <NUM>, a guide tube <NUM> rotatably limited in the sleeve <NUM>, and an actuating device <NUM> actuating the guide tube <NUM> to rotate, wherein the guide tube <NUM> and the hollow spindle <NUM> are synchronously rotatable and are axially expandable and contractable relative to each other; the transmission screw <NUM> and the hollow spindle <NUM> are synchronously rotatable and are axially expandable and contractable relative to each other; the actuating device <NUM> is disposed in the inner tube <NUM> and securely mounted to an upper end of the sleeve <NUM>; and a lower end of the sleeve <NUM> is securely connected with a first transmission nut <NUM> that is thread-fitted with the hollow spindle <NUM>, the first transmission nut <NUM> being securely coupled to the inner tube <NUM>, the upper end of the sleeve <NUM> being movably disposed, i.e., the upper end of the sleeve <NUM> is unfixed, but floating in the inner tube. The vibration generated by the actuating device <NUM> is first transmitted to the first transmission nut <NUM> via the sleeve <NUM> and then transmitted to the lower end of the inner tube <NUM>, instead of being directly transmitted to the lifted platform on top of the inner tube <NUM>, rendering a lighter vibration during the lifting process of the lifted platform, smoother transmission of the transmission assembly, and better user experience; furthermore, as the vibration is directly transmitted to the lower end of the inner tube, the portion upstream of the lower end of the inner tube is substantially not stressed, which significantly reduces the inner stress against the inner tube and thereby improves service life of the inner tube.

In this embodiment, a top plate <NUM> is disposed at the upper end of the inner tube <NUM>, and a gap is present between the actuating device <NUM> and the inner tube <NUM> and between the actuating device <NUM> and the top plate <NUM>, respectively, such that it is less likely for the actuating device <NUM> to contact with the inner tube <NUM> and the top plate <NUM> during operating, and the vibration is not transmitted to the lifted platform via the top plate <NUM> or the inner tube <NUM>, which further improves shock-absorbing effect.

The actuating device <NUM> comprises a motor <NUM>, a gearbox casing <NUM>, and a deceleration mechanism in the gearbox casing <NUM>, wherein the deceleration mechanism comprises a sun gear <NUM> coupled to an output shaft of the motor <NUM>, a bevel gear planet carrier <NUM> transmission-fitted with the sun gear <NUM>, and a spur gear planet carrier <NUM> fitted with an output end of the bevel gear planet carrier <NUM>. The gearbox casing <NUM> includes a gearbox outer case <NUM> and a gearbox cap <NUM>, wherein the deceleration mechanism is disposed in an inner cavity formed by the gearbox outer case <NUM> and the gearbox cap <NUM>; by providing the bevel gear planet carrier <NUM> and the spur gear planet carrier <NUM> which are fitted, power transmission of the actuating device <NUM> becomes smoother and virtually inaudible, which further improves shock-absorbing effect of the transmission assembly. The output end of the spur gear planetary carrier <NUM> is provided with a spline bushing <NUM>, and an inner spline is provided on the guide tube <NUM>, wherein the spline bushing <NUM> and the inner spline are fit to enable the guide tube <NUM> and the spur gear planetary carrier <NUM> to rotate synchronously.

In an embodiment, the guide tube <NUM> is in transmission connection with the hollow spindle <NUM> via the first transmission part <NUM>, wherein the first transmission part <NUM> is securely mounted to the upper end of the hollow spindle <NUM>, the cross-section shape of the first transmission part <NUM> fits with the cross-section shape of the guide tube <NUM>, such that the first transmission part <NUM> can only move axially relative to the guide tube <NUM>, but cannot perform a peripheral rotation.

The transmission screw <NUM> is in transmission connection with the hollow spindle <NUM> via the second transmission part <NUM>, wherein the second transmission part <NUM> is securely mounted to the upper end of the transmission screw <NUM>, the cross-section shape of the second transmission part <NUM> fits with the cross-section shape of the hollow spindle <NUM>, such that the second transmission part <NUM> can only move axially relative to the hollow spindle <NUM>, but cannot perform a peripheral rotation.

The transmission assembly further comprises a positioning block <NUM>, a positioning slot <NUM> is provided on a sidewall of the first transmission nut <NUM>, and a positioning hole is provided at a lower end of the inner tube <NUM>, wherein the positioning block <NUM> sequentially passes through the positioning hole and the positioning slot <NUM> such that the first transmission nut <NUM> and the inner tube <NUM> are easily and conveniently secured at positions in the axial direction.

The upper end of the sleeve <NUM> and the gearbox cap <NUM> of the actuating device <NUM> are coupled via a bolt. The self-lock property of threads renders a simple, reliable coupling between the actuating device <NUM> and the sleeve <NUM>. In an embodiment, the cross section of the sleeve <NUM> has a square shape and four bolts are provided on four corners of the sleeve <NUM>, respectively, such that the coupling between the sleeve <NUM> and the actuating device <NUM> is more secure and reliable.

The lower end of the sleeve <NUM> and the first transmission nut <NUM> are coupled via a bolt, wherein the bolt passes through the first transmission nut <NUM> to fit with the sleeve <NUM> so as to securely fix the sleeve <NUM> to the first transmission nut <NUM>. The self-lock property of threads renders a simple, reliable coupling between the actuating device <NUM> and the sleeve <NUM>. In an embodiment, four bolts are provided on four corners of the sleeve <NUM>, respectively, such that the coupling between the sleeve <NUM> and the actuating device <NUM> is more secure and reliable.

As illustrated in <FIG>, embodiments of the present disclosure further provide a lifting column, comprising a transmission assembly, and an inner tube <NUM> and an outer tube <NUM> which are sequentially fitted from inside to outside, wherein the transmission assembly refers to the transmission assembly for a lifting column recited any of the above technical solutions. Owing to smooth and virtually inaudible operation of the transmission assembly, the lifting process of the lifting column is also stable with less vibration. A lower end of the outer tube <NUM> is provided with a base plate <NUM>, and a lower end of the transmission screw <NUM> is fixed on the base plate <NUM>, and the lifting column is fixed on a mounting plane.

A lower end of the hollow spindle <NUM> is provided with a second transmission nut <NUM> whose position in fixed in the peripheral direction, the second transmission nut <NUM> being thread-fitted with the transmission screw <NUM>. The hollow spindle <NUM> is rotatably positioned in the axial direction with respect to the second transmission nut <NUM>, a locking structure <NUM> limiting the second transmission nut <NUM> from rotation is provided outside the second transmission nut <NUM>, the locking structure <NUM> being disposed in the outer tube <NUM> and movably fit with the outer tube <NUM>; movable fitting between the locking structure <NUM> and the outer tube <NUM> enables the locking structure <NUM> and the outer tube <NUM> to move freely in the axial direction, such that the locking structure <NUM> may ascend and descend in the inner tube <NUM> along with the second transmission nut <NUM>.

In an embodiment, the locking structure <NUM> comprises a first locking block <NUM> and a second locking block <NUM>, wherein the first locking block <NUM> and the second locking block <NUM>, after being folded, form an accommodation slot, wherein the second transmission nut <NUM> is disposed in the accommodation slot; a limiting hole is provided in the accommodation slot, and a limiting protrusion is provided on the second transmission nut <NUM>, wherein fitting between the limiting hole and the limiting protrusion causes the locking structure <NUM> to be fixed at a peripheral position opposite to the second transmission nut <NUM>, which limits rotation of the second transmission nut <NUM>; meanwhile, the cross-section shape of the locking structure <NUM> fits with the cross-section shape of the outer case, such that the locking structure <NUM> can only move axially in the outer case, but cannot rotate peripherally.

An operating process of the lifting column in this embodiment is described as such: the motor <NUM> in the actuating device <NUM> actuates the sun gear <NUM> to rotate, the sun gear <NUM> brings the bevel gear planetary carrier <NUM> to rotate, the bevel gear planetary carrier moves the spur gear planetary carrier <NUM> to rotate, the spur gear planetary carrier <NUM> brings the spline bushing <NUM> to rotate, the spline bushing <NUM> moves the guide tube <NUM> to rotate, the guide tube <NUM> brings the hollow spindle <NUM> via the first transmission part <NUM> to rotate synchronously, and the hollow spindle <NUM> moves the transmission screw <NUM> via the second transmission part <NUM> to rotate; as the transmission screw <NUM> and the base plate <NUM> are axially limited, the second transmission nut <NUM> ascends and descends along the transmission screw <NUM>, the hollow spindle <NUM>, while rotating, ascends and descends along with the second transmission nut <NUM>, the first transmission nut <NUM> ascends and descends axially along the hollow spindle <NUM>, and the first transmission nut <NUM> brings the inner tube <NUM> to ascend and descend, thereby realizing lifting of the lifting column.

It is understood that in an alternative embodiment, no gap is provided between the actuating device and the inner tube.

It is understood that in an alternative embodiment, the upper end of the sleeve and the gearbox cap are coupled via a bayonet connection.

It is understood that in an alternative embodiment, the lower end of the sleeve and the first transmission nut are coupled via a bayonet connection.

It is understood that in an alternative embodiment, a limiting protrusion is provided in the accommodation slot, and a limiting hole is provided on the second transmission nut.

As shown in <FIG>, the second embodiment differs from the first embodiment mainly in that the top plate <NUM> is a flexible top plate made of a flexible material; in this case, no gap is provided between the actuating device and the flexible top plate, because the flexible top plate may buffer vibration from actuating device.

As shown in <FIG>, the third embodiment differs from the first embodiment mainly in that the transmission assembly further comprises an intermediate tube <NUM> disposed between the inner tube <NUM> and the outer tube <NUM>. This setting offers a beneficial effect that the three-stage tube setting enables synchronous expansion and contraction, rendering a reduced distance for the lifting column.

In this embodiment, the lower end of the hollow spindle <NUM> is provided with a second transmission nut <NUM> whose peripheral position is fixed, the second transmission nut <NUM> being thread-fitted with the transmission screw <NUM>; the hollow spindle <NUM> is rotatably positioned in the axial direction with respect to the second transmission nut <NUM>, a locking structure <NUM> limiting the second transmission nut <NUM> from rotation is provided outside the second transmission nut <NUM>, and the locking structure <NUM> is securely coupled to the lower end of the intermediate tube <NUM>, such that axial movement of the second transmission nut <NUM> can bring the intermediate tube <NUM> to ascend and descend relative to the outer tube, rendering a smoother transmission.

An operating process of the lifting column in this embodiment is described as such: the motor in the actuating device <NUM> actuates the sun gear to rotate, the sun gear brings the bevel gear planetary carrier to rotate, the bevel gear planetary carrier moves the spur gear planetary carrier to rotate, the spur gear planetary carrier brings the spline bushing <NUM> to rotate, the spline bushing <NUM> moves the guide tube <NUM> to rotate, the guide tube <NUM> brings the hollow spindle <NUM> to rotate synchronously via the first transmission part <NUM>, and the hollow spindle <NUM> moves the transmission screw <NUM> to rotate via the second transmission part <NUM>; as the transmission screw <NUM> and the base plate <NUM> are axially limited, the second transmission nut <NUM> ascends and descends axially along the transmission screw <NUM>, the second transmission nut <NUM> brings the intermediate tube <NUM> to ascend and descend via the locking structure <NUM>, the hollow spindle 2ascends and descends along with the second transmission nut <NUM> while rotating, the first transmission nut <NUM> ascends and descends axially along the hollow spindle <NUM>, and the first transmission nut <NUM> brings the inner tube <NUM> to ascend and descend, thereby realizing lifting of the lifting column.

Claim 1:
Transmission assembly for a lifting column that includes an inner tube (<NUM>), comprising: an exteriorly threaded hollow spindle (<NUM>), a transmission screw (<NUM>) disposed in the hollow spindle (<NUM>), a sleeve (<NUM>) fitted over the hollow spindle (<NUM>), a guide tube (<NUM>) limited in the sleeve (<NUM>), and an actuating device(<NUM>) actuating the guide tube (<NUM>) to rotate, the guide tube (<NUM>) and the hollow spindle (<NUM>) being synchronously rotatable and axially expandable and contractable relative to each other, the transmission screw (<NUM>) and the hollow spindle (<NUM>) being synchronously rotatable and axially expandable and contractable relative to each other; wherein the actuating device (<NUM>) is disposed in the inner tube (<NUM>) and a lower end of the sleeve (<NUM>) is securely connected with a first transmission nut (<NUM>), characterized in that:
the actuating device (<NUM>) is securely mounted to an upper end of the sleeve (<NUM>); and the first transmission nut (<NUM>) is thread-fitted with the hollow spindle (<NUM>) and securely coupled to the inner tube (<NUM>), and the upper end of the sleeve (<NUM>) is movably disposed.