CN210890723U - Liftable supporting seat - Google Patents

Abstract

The utility model provides a liftable supporting seat sets up on a base to be used for bearing a display device, mainly include a stand, an at least slider, an at least meshing mechanism and a the control unit always. When the control unit is in the unlocking state, the engagement mechanism is separated, so that the sliding piece can move between the highest position and the lowest position.

Description

Liftable support base

technical field

The utility model relates to a liftable support base, in particular to a liftable support base for carrying a display panel.

Background technique

The existing point of service system includes a support device and a display device, and the support device usually has a brake block, so that the display device can be stably stopped at any specific height. However, it is usually necessary to touch the display device with hands to operate, so additional force is applied to the support device from time to time, which may cause the brake pads in the support device to become less effective, and cannot provide a stable support force to support during use. Therefore, the function of stopping the display device at a certain height is lost.

Therefore, the present invention provides a liftable support base with a meshing mechanism, which utilizes the first teeth and the second teeth to be selectively separated or engaged, which can provide a more stable support force and have a longer service life.

Utility model content

A main purpose of the present invention is to provide a liftable support base that can be used to carry a display device, which mainly includes an upright column, including at least one rail; at least one sliding piece, the sliding piece correspondingly slides on the rail; a meshing mechanism, disposed on the upright column and the sliding member, and comprising a plurality of first teeth and a plurality of second teeth; and a control unit linked to one of the first teeth and the second teeth , and switch between a locked state and an unlocked state; wherein, when the control unit is in the locked state, the first teeth and the second teeth are engaged with each other and remain relatively stationary, and the sliding member stops at a highest Any position between the position and a lowest position, when the control unit is in the unlocked state, the second tooth is separated from the first tooth, so that the slider can be in the highest position and the lowest position action in between.

In a preferred embodiment, the track extends along a first axis, the sliding member reciprocates along the first axis, and the first teeth and the second teeth can be relatively separated along a first direction.

In a preferred embodiment, the control unit includes a button, the button is linked with one of the first teeth and the second teeth, the button tends to remain in an original position, and can be pushed away by an external force. In the original position, when the control unit is in the locked state, when the button is pressed by an external force and leaves the original position, the control unit is in the unlocked state.

In a preferred embodiment, the external force presses the button along a second direction.

In a preferred embodiment, the first direction is parallel to the first axis, and the second direction is perpendicular to the first axis.

In a preferred embodiment, the control unit further includes at least one return spring, the return spring connects the upright post and the button, so that the button tends to remain in the original position.

In a preferred embodiment, the control unit further includes at least one guide post, the guide post protrudes from the button perpendicular to the first axis, and the return spring is sleeved thereon.

In a preferred embodiment, the liftable support base further includes at least a constant force spring, the constant force spring includes a winding section and a stretching section, and the winding section is arranged on the rail and the sliding member One of them, the stretching section is arranged on the other of the track and the sliding member

In a preferred embodiment, the meshing mechanism further includes a plurality of third teeth, a first locking plate, a first gear and a first rack, and the first locking plate is movably arranged on the upright column. The first gear is arranged on the upright column, the first rack is arranged on the sliding member, the first tooth is formed on the first gear, and the second tooth is formed on the first locking plate , the third tooth is formed on the first rack; the first tooth is always engaged with the third tooth, when the control unit is in the unlocked state, the first locking plate is away from the first gear, Therefore, the second tooth is separated from the first tooth; when the control unit is in the locked state, the first locking plate is close to the first gear, so the second tooth is separated from the first tooth bite.

In a preferred embodiment, when the control unit is in the unlocked state, the first gear and the first rack are driven, so that the sliding member can be at the highest position and the lowest position on the first shaft relative to the upright column. Swipe back and forth between positions.

In a preferred embodiment, the meshing mechanism further includes a return spring, the return spring connects the upright post and the first locking plate, and tends to keep the first locking plate away from the first gear, the button has an abutting surface obliquely intersecting with the first axis, the first locking plate has a contacting surface obliquely intersecting with the first axis; when the control unit is in the locked state, the abutting surface pushes against the The abutting surface makes the first locking plate adjacent to the first gear, so that the first teeth and the second teeth are engaged with each other; when the control unit is in the unlocked state, the abutting surface and the abutting surface The detent surfaces slide in displacement with each other, and the return spring keeps the first locking plate away from the first gear, so that the first teeth and the second teeth are separated from each other.

In a preferred embodiment, the first locking plate has at least one elongated through hole and at least one fixing column, the fixing column passes through the elongated through hole and is disposed on the upright column, the first locking plate It can reciprocate along the first axis relative to the upright post.

In a preferred embodiment, the button further has a protruding portion, the protruding portion extends along the first axis, and the abutting surface is formed on the protruding portion.

In a preferred embodiment, the meshing mechanism further includes a plurality of third teeth, a first locking plate, a first gear, and a first rack, and the first locking plate is movably disposed on the slide. The first gear is arranged on the sliding piece, the first rack is arranged on the upright column, the first tooth is formed on the first gear, and the second tooth is formed on the first locking plate, the third teeth are formed on the first rack; the first teeth are constantly engaged with the third teeth, when the control unit is in the unlocked state, the first locking plate is away from the first gear , so that the first tooth and the second tooth are separated; when the control unit is in the locked state, the first locking plate is close to the first gear, so the first tooth and the second tooth are separated. Teeth bite.

In a preferred embodiment, when the control unit is in the unlocked state, the first gear and the first rack are driven, so that the sliding member can be at the highest position and the lowest position on the first shaft relative to the upright column. Slide back and forth between.

In a preferred embodiment, the meshing mechanism further includes a return spring, the return spring connects the slider and the first locking plate, and tends to keep the first locking plate away from the first gear, the button has an abutting surface obliquely intersecting with the first axis, the first locking plate has a contacting surface obliquely intersecting with the first axis; when the control unit is in the locked state, the abutting surface pushes against the The abutting surface makes the first locking plate adjacent to the first gear, so that the first teeth and the second teeth are engaged with each other; when the control unit is in the unlocked state, the abutting surface and the abutting surface The detent surfaces slide in displacement with each other, and the return spring keeps the first locking plate away from the first gear, so that the first teeth and the second teeth are separated from each other.

In a preferred embodiment, the first locking plate has at least one elongated through hole and at least one fixing column, the fixing column passes through the elongated through hole and is disposed on the sliding member, the first locking plate The stop plate can reciprocate relative to the sliding member along the first axis.

In a preferred embodiment, the button further has a protruding portion, the protruding portion extends along the first axis, and the abutting surface is formed on the protruding portion.

In a preferred embodiment, the meshing mechanism further includes a first rack and a second rack, the first rack is disposed on the sliding member, the first teeth are formed on the first rack, the The second rack is disposed on the upright column, and the second teeth are formed on the second rack.

In a preferred embodiment, the engagement mechanism further includes a return spring, the return spring connects the slider and the first rack and tends to keep the first rack away from the second rack.

Description of drawings

Fig. 1 is the use state diagram of the first embodiment of the liftable support seat of the present invention;

Fig. 2 is the three-dimensional schematic diagram of the first embodiment of the liftable support seat of the present invention;

3 is a perspective exploded view of the first embodiment of the liftable support seat of the present invention;

4 is a cross-sectional view of the first embodiment of the liftable support base of the present invention;

5 is an action sectional view of the first embodiment of the liftable support seat of the present invention;

6 is a perspective view of the first embodiment of the liftable support base of the present invention at the highest position;

7 is a cross-sectional view of the second embodiment of the liftable support base of the present invention;

8 is an action sectional view of the second embodiment of the liftable support seat of the present invention;

FIG. 9 is a partial cross-sectional view of the third embodiment of the elevating support base of the present invention; and

FIG. 10 is a partial action sectional view of the third embodiment of the elevating support of the present invention.

【Symbol Description】

1000, 3000, 4000 liftable support base

2000 Display Unit

1 upright post

11 opening

12 accommodating space

13 tracks

2 Sliders

21 Board body

211 Joint

22 wraps

3 meshing mechanism

31 First tooth

32 Second tooth

33 Third tooth

34 The first locking plate

341 Long Perforation

342 Arrival

343 Fixed post

344 Gasket

35 First gear

36 First rack

37 Return spring

38 Second rack

4 Control unit

41 keys

411 Protrusion

412 Abutment surface

42 return spring

43 shell

44 Guide post

5 constant force spring

51 winding section

52 stretch section

53 Mounts

D1 first direction

D2 second direction

X first axis

Detailed ways

Please refer to FIG. 1 and FIG. 2 , respectively showing the use state of the liftable support base 1000 according to the first embodiment of the present invention and the three-dimensional schematic diagram of FIG. 2 . Two engaging mechanisms 3 , a control unit 4 , and two constant force springs 5 . The liftable support base 1000 is used to carry a display device 2000 . In the present invention, the display device 2000 is a display panel, and in other embodiments of the present invention, the display device 2000 is not limited to a display panel, and can be adjusted and replaced with other display devices according to requirements.

Please also refer to the three-dimensional exploded view of the liftable support base 1000 shown in FIG. 3 , the upright column 1 is a hollow cylinder, and has an opening 11 and an accommodating space 12 that communicate with each other, and two rails 13 . The rails 13 are respectively located on two sides of the accommodating space 12 and extend along a first axis X for the sliding members 2 to be respectively disposed thereon.

In this embodiment, the sliding member 2 is slidably disposed on the rail 13 and reciprocatingly slides along the first axis X between a highest position and a lowest position (ie, the up and down direction in FIG. 2 ). Each of the sliding members 2 has a plate body 21 , two covering sleeves 22 , and a fixing seat 23 . The covering sleeves 22 are engaged, so when the sliding member 2 is slid on the corresponding rails 13 , the covering sleeves 22 are in contact with the rails 13 . In addition, the fixing seat 23 is connected below the plate body 21 .

In this embodiment, each of the meshing mechanisms 3 includes a plurality of first teeth 31, a plurality of second teeth 32, a plurality of third teeth 33, a first locking plate 34, a first gear 35, a The first rack 36, and a return spring 37. The first tooth 31 is formed on the first gear 35 ; the second tooth 32 is formed on the first locking plate 34 ; and the third tooth 33 is formed on the first rack 36 .

In each of the engaging mechanisms 3 , the first locking plate 34 has two elongated through holes 341 , an inclined resisting surface 342 (as shown in FIG. 4 ), two fixing posts 343 , and two spacers 344, and a locking plate body 345, the elongated through hole 341 is formed in the locking plate body 345 extending along the first axis X, and the fixing column 343 passes through the upright column 1, the elongated through hole 341, and the washer 344, the locking plate 345 is arranged on the inner surface of the upright column 1, but the fixing column 343 does not lock the locking plate 345, therefore, the locking plate The body 345 can reciprocate relative to the upright post 1 along the first axis X in a small range through the elongated hole 341 , so that the second teeth 32 can be engaged with or separated from the first teeth 31 .

In each of the meshing mechanisms 3 , the first gear 35 is disposed on the inner surface of the upright post 1 and is adjacent to the opening 11 of the upright post 1 . The first rack 36 is disposed on the slider 2 , and the third teeth 33 formed on the first rack 36 and the first teeth 31 formed on the first gear 35 engage with each other, Therefore, when the first rack 36 slides with the sliding member 2 , it drives with the first gear 35 .

Referring to FIG. 2 , one end of each of the restoring springs 37 is fixed on the first locking plate 34 , and the other end is fixed on the upright column 1 , and has a pre-tensioned contraction in the direction of the first axis X The force (that is, the return spring 37 is a tension spring) tends to move the first locking plate 34 away from the first gear 35 .

Referring to FIG. 4 , in each of the meshing mechanisms 3 , when the second teeth 32 are engaged with the first teeth 31 , the first gear 35 cannot rotate, and therefore cannot interact with the first rack 36 . transmission, thereby restricting the sliding of the sliding member 2, so that it is fixed in a certain position. However, please refer to FIG. 5 , when the second tooth 32 and the first tooth 31 are separated along a first direction D1 (roughly parallel to the first axis X), the first gear 35 can be separated from the first tooth The bar 36 is driven to rotate, so that the sliding member 2 can slide back and forth along the first axis X relative to the upright column 1 .

The control unit 4 is disposed in the accommodating space 12 of the upright column 1, and is partially exposed by the opening 11. The control unit 4 includes a button 41, two return springs 42, a housing 43, and two guides The post 44, the button 41 has two protrusions 411 extending upward along the first axis X, and two abutting surfaces 412 obliquely inclined with the first axis X, the abutting surfaces 412 are formed on the On the protruding portion 411 , the abutting surface 412 abuts the abutting surface 342 of the first locking plate 34 , and the return spring 42 is sleeved on the guide protruding from the button 41 toward a second direction D2 . on the post 44 and abut against the button 41 and the (inner surface of the upright post 1 ), so that the key 41 tends to remain in an original position, the shell 43 covers the key 41 and exposes the opening 11 of the upright post 1 and the user can exert force on it. At this time, the control unit 4 is in a locked state. When an external force presses the button 41 in the second direction D2 (slightly perpendicular to the first axis X), the button 41 is separated from the original position, and the return spring 42 is compressed (as shown in FIG. 5 ). The first locking plate 34 and the protruding portion 411 will be displaced along the abutting surface 412 and the abutting surface 342. At this time, the control unit 4 is in an unlocked state; and when the external force is removed, all the The return spring 42 releases the elastic force and makes the button 41 spring back to the original position (as shown in FIG. 4 ), and the control unit 4 is converted into the locked state.

Each of the constant-force springs 5 includes a winding section 251 and a stretching section 52 . The winding section 51 is disposed on the fixing seat 23 , and the stretching section 52 is disposed on the upright column 1 . When the sliding member 2 drives the winding section 51 of the constant force spring 5 to move upward along the first axis X together, the length of each of the constant force springs 5 allocated to the stretching section 52 decreases gradually. As the length of the winding section 51 increases gradually, on the contrary, when the sliding member 2 drives the constant force spring 5 to move downward along the first axis X, each of the constant force springs 5 is assigned to the pulling force. The length of the extension section 52 is gradually increased, and the length allocated to the winding section 51 is gradually decreased. The constant force spring 5 constantly provides an elastic force. In other embodiments, the number of constant force springs is not limited, and can be adjusted according to the required supporting elastic force.

In detail, the control unit 4 can be changed between a locked state and an unlocked state. Please refer to the cross-sectional view shown in FIG. 4 again. When there is no external force (ie, under normal conditions), the control unit 4 is in the In this locked state, the second teeth 32 and the first teeth 31 are engaged with each other. Therefore, the first rack 36 , the first gear 35 , and the first locking plate 34 are connected to each other. There is no transmission between them, so that the position of the sliding member 2 is locked and cannot be slid.

As shown in FIG. 5 , when an external force presses the button 41 of the control unit 4 in the second direction D2, the button 41 is displaced toward the second direction D2, compressing the return spring 42, and the button 41 is displaced toward the second direction D2. The abutting surface 412 and the abutting surface 342 which abut against each other with the first locking plate 34 are misaligned, so the first locking plate 34 will be reset due to the pre-stretched The contraction force provided by the spring 42 moves downward along the first direction D1. The moved second teeth 32 are separated from the first teeth 31. At this time, the control unit 4 is released from its original position and is in the unlocked state, and the first rack 36 can be connected to the first Gear 35 transmission. Therefore, the user can apply an external force to make the slider 2 in the outer rail 13 along the first axis X at the highest position (as shown in FIG. 6 ) and the lowest position (as shown in FIGS. 2 and 4 ) Reciprocating sliding between the shown), and at this time, because the constant force spring 5 constantly provides the elastic force to support the sliding member 2, the carrier plate (not shown) carrying the display device 2000, and the display device 2000, The user can easily move the slider 2 to adjust its height.

Next, as shown in FIG. 6 , when the slider 2 is adjusted to the desired position (the highest position is shown in FIG. 6 ), the external force pressing the control unit 4 is removed, and the button 41 is caused by the return spring 42 The released elastic force moves in the opposite direction to the second direction D2 to return to the original position, and at the same time, the abutting surface 412 of the button 41 pushes the abutting surface 342 of the first locking plate 34 , so that the first locking plate 34 moves in a direction opposite to the first direction D1, so that the second teeth 32 and the first teeth 31 are engaged, and then the first gear 35 and the first teeth are fixed. Article 36.

According to another embodiment of the first embodiment, the first locking plate 34 and the control unit 4 are directly fixed or integrally formed. It is possible to press the control unit 4 with an external force to make it out of the original position and reach the unlocked state, and when the external force is removed, the control unit 4 springs back to the original position and returns to the locked state, which will not be repeated here.

Please refer to FIG. 7 , which is a cross-sectional view of a liftable support base 3000 according to a second embodiment of the present invention. In the liftable support base 3000 of this embodiment, the upright column 1 , the sliding member 2 , and the The structure and connection relationship of the constant force spring 5 are the same as those of the above-mentioned embodiment, and therefore are not repeated here. The difference between this embodiment and the first embodiment is that the control unit 4 is disposed on the sliding member 2 and slides back and forth with the sliding member 2 , while the first locking plate 34 and the The first gear 35 is disposed on the sliding member 2 together with the control unit 4 , and the first rack 36 is fixed on the upright column 1 .

In detail, the first locking plate 34 and the first gear 35 are substantially the same as the first embodiment, and in each of the meshing mechanisms 3 , the first teeth 31 are formed on the first gear 35, the second teeth 32 are formed on the first locking plate 34, the third teeth 33 are formed on the first rack 36, and the first locking plate 34 has two elongated holes ( The first locking plate 34 is disposed on the sliding member 2 through two fixing posts 343 correspondingly penetrated through the elongated hole (not shown) and an inclined resisting surface 342. , and can reciprocate relative to the sliding member 2 along the first axis X in a small range, so that the second teeth 32 can be separated from the first teeth 31 in a first direction D1 or opposite to the first direction The direction of D1 is engaged, and when the second teeth 32 and the first teeth 31 are separated in a first direction D1, the first teeth 31 and the third teeth 33 are engaged with each other, and the first teeth 31 are engaged with the first teeth 31. When the bars 36 are driven to each other, the first gear 35 can slide relative to the upright column 1 along with the sliding member 2 .

In each of the engaging mechanisms 3, one end of the return spring (not shown) is fixed on the first locking plate 34, and the other end is fixed on the sliding member 2, and is connected to the first shaft. There is a pre-stretching force in the X direction, which tends to keep the first locking plate 34 away from the first gear 35 .

The control unit 4 is located in the accommodating space 12 of the upright column 1 and is connected to the sliding member 2. The control unit 4 is substantially the same as that of the first embodiment, but the return spring 42 included therein is provided Between the button 41 and the sliding member 2 , and abutting the button 41 and the sliding member 2 , the button 41 tends to remain in an original position. Therefore, as shown in FIG. 8 , when an external force presses the button 41 in a second direction D2 (slightly perpendicular to the first axis X) to make it leave the original position, the return spring 42 is compressed; and When the external force is removed, the return spring 42 releases the elastic force and makes the button 41 spring back to the original position (as shown in FIG. 7 ).

The control unit 4 can be changed between a locked state (as shown in FIG. 7 ) and an unlocked state (as shown in FIG. 8 ). Please refer to the cross-sectional view shown in FIG. 7 . down), the control unit 4 is in the locked state, at this time, the second teeth 32 and the first teeth 31 are engaged with each other, so the first rack 36, the first gear 35, and the The first locking plates 34 cannot transmit each other, thereby locking the position of the sliding member 2 so that it cannot slide.

When an external force presses the button 41 of the control unit 4 in the second direction D2 , the button 41 compresses the return spring 42 , and the button 41 and the first locking plate 34 resist each other. The abutting surface 412 and the abutting surface 342 are misaligned, so the first locking plate 34 will move along the first locking plate 34 due to the contraction force provided by the pre-stretched return spring (not shown). One direction D1 is separated, so that the control unit 4 is released from its original position and is in the unlocked state. At this time, the first gear 35 and the first rack 36 can be driven, and the user can apply an external force, so that all the The slider 2 reciprocates along the first axis X in the outer rail 13 between the highest position (as shown in FIG. 8 ) and the lowest position (as shown in FIG. 7 ), and the first gear 35. The first locking plate 34 and the control unit 4 slide back and forth along the first axis X together with the sliding member 2 . Because the constant force spring 5 constantly provides an elastic force to support the slider 2 , the first gear 35 , the first locking plate 34 , the control unit 4 , and the bearing plate that carries the display device 2000 (not shown in the figure) shown), and the display device 2000, the user can easily move the slider 2 to adjust its height position.

Next, when the sliding member 2 is adjusted to the desired position, the external force pressing the control unit 4 is removed, and the button 41 is directed in the opposite direction to the second direction D2 due to the release elastic force of the return spring 42 move to return to the original position, and at the same time, the abutting surface 412 of the button 41 pushes the abutting surface 342 of the first locking plate 34, so that the first locking plate 34 is opposite to the first locking plate 34 along the Move in a direction D1 until the first teeth 31 and the second teeth 32 are engaged, so as to fix the first gear 35 and the first rack 36 , so that the control unit 4 returns to the locked state.

Please refer to FIG. 9 , which shows a partial cross-sectional view of a liftable support base 4000 according to the third embodiment of the present invention. In the liftable support base 4000 of this embodiment, the structures and connection relationships of the upright column 1 , the sliding member 2 , and the constant force spring 5 are the same as those in the above-mentioned embodiment, and are not repeated here. The difference between this embodiment and the above-mentioned embodiment is that each of the meshing mechanisms 3 includes a plurality of first teeth 31 , a plurality of second teeth 32 , a first rack 36 , a second rack 38 , and A return spring (not shown). The first teeth 31 are formed on the first rack 36 ; the second teeth 32 are formed on the second rack 38 . The first teeth 31 and the second teeth 32 can be selectively engaged with or separated from each other. One end of the return spring (not shown) is fixed on the first rack 36, and the other end is fixed on the upright column 1, and provides a return spring force in the direction perpendicular to the first axis X, which tends to The first rack 36 is brought close to the second rack 38 .

The control unit (not shown) in this embodiment is substantially the same as that in Embodiment 1. However, in this embodiment, when there is no external force (ie, under normal conditions), the control unit 4 is in the locked state, At this time, the first teeth 31 and the second teeth 32 are engaged with each other, thereby locking the position of the sliding member 2 so that it cannot slide. However, as shown in FIG. 10 , when an external force presses the button (not shown) of the control unit (not shown) to make it move away from the original position, the first rack 36 moves to the first gear along with the control unit 4 . The control unit 4 moves in the direction of the second direction D2 and is separated from the second rack 38. At this time, the control unit 4 is in the unlocked state, and the user can apply force to make the sliding member 2 face the outer rail (not shown in the figure). ) slide along the first axis X, and reciprocate between the highest position and the lowest position to adjust its position, and when the slider 2 is adjusted to the desired position, remove and press the button (not shown in the figure). shown), the return spring releases the elastic force so that the button (not shown) returns to the original position, and at the same time, the first rack 36 moves in the opposite direction to the second direction D2, so that the first When the teeth 31 and the second teeth 32 are engaged, the control unit 4 returns to the locked state.

The above-mentioned embodiments are only used to illustrate the embodiments of the present invention and to explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily accomplished by those skilled in the art fall within the scope of the present invention.

Claims (14)

1. The utility model provides a bear display device's liftable supporting seat which characterized in that includes:

a vertical column comprising at least one track;

the sliding piece is correspondingly arranged on the track in a sliding manner;

at least one engaging mechanism, which is arranged on the upright post and the sliding part and comprises a plurality of first teeth and a plurality of second teeth; and

a control unit which is linked with one of the first tooth and the second tooth and is switched between a locking state and an unlocking state;

when the control unit is in the unlocking state, the second tooth is separated from the first tooth, so that the sliding part can move between the highest position and the lowest position.

2. The liftable support base of claim 1, wherein the rail extends along a first axis, the slider reciprocates along the first axis, and the first and second teeth are separable from each other along a first direction.

3. The liftable support stand of claim 2, wherein the control unit comprises a button, the button is coupled to one of the first tooth and the second tooth, the button is inclined to be maintained at an original position and can be pressed by an external force to be separated from the original position, the control unit is in the locked state at the original position, and the control unit is in the unlocked state at the moment the button is pressed by an external force to be separated from the original position.

4. The liftable support stand of claim 3, wherein the external force presses the key in a second direction, the first direction is parallel to the first axis, and the second direction is perpendicular to the first axis.

5. The liftable support stand of claim 3, wherein the control unit further comprises at least one return spring connecting the upright post and the button, thereby biasing the button to remain in the original position.

6. The liftable support stand of claim 5, wherein the control unit further comprises at least one guide post protruding from the key perpendicularly to the first axis and allowing the return spring to be sleeved thereon.

7. The liftable support base of claim 6, further comprising at least one constant force spring, wherein the constant force spring comprises a winding section and an extension section, the winding section is disposed on one of the rail and the sliding member, and the extension section is disposed on the other of the rail and the sliding member.

8. The liftable support base of any one of claims 4 to 7, wherein the engagement mechanism further comprises a plurality of third teeth, a first engaging plate, a first gear and a first rack, the first engaging plate is movably disposed on the upright column, the first gear is disposed on the upright column, the first rack is disposed on the slider, the first teeth are formed on the first gear, the second teeth are formed on the first engaging plate, and the third teeth are formed on the first rack; the first tooth is constantly engaged with the third tooth, and when the control unit is in the unlocking state, the first clamping plate is far away from the first gear, so that the second tooth is separated from the first tooth; when the control unit is in the locking state, the first stop plate is close to the first gear, so that the second teeth are meshed with the first teeth.

9. The liftable support base of claim 8, wherein when the control unit is in the unlocked state, the first gear is in transmission with the first rack such that the slider can slide reciprocally on the first axis between the highest position and the lowest position with respect to the upright post, the engagement mechanism further comprises a return spring connecting the upright post and the first locking plate and tending to move the first locking plate away from the first gear, the key has a top abutment surface inclined with respect to the first axis, and the first locking plate has an abutment surface inclined with respect to the first axis; when the control unit is in the locking state, the abutting surface pushes the abutting surface to enable the first clamping plate to be adjacent to the first gear, and therefore the first tooth and the second tooth are meshed with each other; when the control unit is in the unlocking state, the abutting surface and the abutting surface slide in a staggered mode, the return spring enables the first clamping plate to be far away from the first gear, and therefore the first tooth and the second tooth are separated from each other.

10. The liftable support base of claim 9, wherein the first locking plate has at least one elongated through hole and at least one fixing post passing through the elongated through hole and disposed on the upright post, the first locking plate is capable of reciprocating relative to the upright post along the first axis, the key further has a protrusion extending along the first axis, and the abutting surface is formed on the protrusion.

11. The liftable support base of any one of claims 4 to 7, wherein the engagement mechanism further comprises a plurality of third teeth, a first engaging plate, a first gear and a first rack, the first engaging plate is movably disposed on the sliding member, the first gear is disposed on the sliding member, the first rack is disposed on the upright post, the first teeth are formed on the first gear, the second teeth are formed on the first engaging plate, and the third teeth are formed on the first rack; the first tooth is constantly meshed with the third tooth, and when the control unit is in the unlocking state, the first clamping plate is far away from the first gear, so that the first tooth is separated from the second tooth; when the control unit is in the locking state, the first stop plate is close to the first gear, so that the first tooth is meshed with the second tooth.

12. The liftable support base of claim 11, wherein when the control unit is in the unlocked state, the first gear is in transmission with the first rack such that the slider can slide reciprocally on the first axis between the highest position and the lowest position with respect to the upright post, the engagement mechanism further comprises a return spring connecting the slider and the first locking plate and tending to move the first locking plate away from the first gear, the key has a top abutment surface inclined with respect to the first axis, and the first locking plate has a stop abutment surface inclined with respect to the first axis; when the control unit is in the locking state, the abutting surface pushes the abutting surface to enable the first clamping plate to be adjacent to the first gear, and therefore the first tooth and the second tooth are meshed with each other; when the control unit is in the unlocking state, the abutting surface and the abutting surface slide in a staggered mode, the return spring enables the first clamping plate to be far away from the first gear, and therefore the first tooth and the second tooth are separated from each other.

13. The liftable support base of claim 12, wherein the first locking plate has at least one elongated through hole and at least one fixing post, the fixing post is disposed on the sliding member through the elongated through hole, the first locking plate is capable of moving back and forth along the first axis relative to the sliding member, the key further has a protrusion extending along the first axis, and the abutting surface is formed on the protrusion.

14. The liftable support base of any one of claims 4 to 7, wherein the engaging mechanism further comprises a first rack and a second rack, the first rack being disposed on the sliding member, the first tooth being formed on the first rack, the second rack being disposed on the upright post, the second tooth being formed on the second rack, the engaging mechanism further comprising a return spring connecting the sliding member and the first rack and tending to move the first rack away from the second rack.

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