CN116518257A - Lifting and rotating bracket and multimedia equipment - Google Patents

Abstract

The application relates to the field of multimedia equipment and discloses a lifting rotating bracket which comprises a lifting-rotating adjusting mechanism, wherein the lifting-rotating adjusting mechanism comprises a driving bevel gear which is horizontally arranged; the first driven bevel gear and the second driven bevel gear can synchronously lift, and the first driven bevel gear and the second driven bevel gear are alternately meshed with the driving bevel gear in the lifting process; an external telescopic tube fixed with the first driven bevel gear, wherein the first driven bevel gear rotates to realize telescopic adjustment of the external telescopic tube; the built-in telescopic tube is fixed with the second driven bevel gear, synchronously rotates along with the second driven bevel gear, and is arranged in the external telescopic tube in a penetrating way and is connected with the external telescopic tube through a bearing; the top end of the built-in telescopic tube is provided with a fixed bracket. A multimedia device is also disclosed, comprising a lifting rotary support and a multimedia device main body arranged on the lifting rotary support. The height and the angle of the main body of the multimedia equipment can be quickly adjusted, and the multimedia equipment is convenient and practical.

Description

Lifting and rotating bracket and multimedia equipment

technical field

The present application relates to the technical field of multimedia equipment, in particular to a lifting and rotating support and multimedia equipment.

Background technique

Multimedia equipment integrates multiple technologies such as infrared touch technology, intelligent office teaching software, multimedia network communication technology, and high-definition flat panel display technology. It integrates projectors, projection screens, electronic whiteboards, computers (optional), TVs, A multi-functional interactive multimedia device that integrates multiple devices such as a touch screen, upgrades the traditional display terminal to a full-featured human-computer interaction device. Through this product, users can realize writing, annotation, painting, multimedia entertainment and computer operation, and can easily perform wonderful interactive classrooms by directly turning on the device.

As is known, at present, most multimedia equipments are erected with liftable brackets. However, during the installation and use of multimedia equipments, it is found that the angle of multimedia equipments needs to be adjusted so that students can see the picture clearly from different angles. There are few rotatable adjustment functions, so it is very troublesome to lift the entire multimedia device together with the bracket to rotate and adjust the angle every time.

Contents of the invention

The main purpose of the present application is to provide a lifting and rotating bracket and multimedia equipment, aiming to solve the problem in the prior art that traditional multimedia equipment and its brackets do not have a rotation function and it is not convenient to adjust the placement angle of the multimedia equipment.

The technical scheme that this application adopts is as follows:

first:

The present application provides a lifting and rotating bracket, including a fixed bracket and a lifting-rotation adjustment mechanism, and the lifting-rotation adjustment mechanism is used to realize the lifting and rotation of the fixed bracket;

Wherein, the lift-rotation adjustment mechanism includes:

Drive bevel gear arranged horizontally;

The first driven bevel gear and the second driven bevel gear that can move synchronously up and down, and the first driven bevel gear and the second driven bevel gear alternately mesh with the driving bevel gear during the lifting process;

An external telescopic sleeve fixed to the first driven bevel gear, and the first driven bevel gear rotates to realize telescopic adjustment of the external telescopic sleeve;

A built-in telescopic sleeve fixed to the second driven bevel gear, the built-in telescopic sleeve rotates synchronously with the second driven bevel gear, and the built-in telescopic sleeve runs through the external telescopic sleeve , the built-in telescopic sleeve is rotationally connected to the external telescopic sleeve through a bearing;

The fixing bracket is arranged on the top end of the built-in telescopic sleeve.

Further, the lifting and rotating support further includes a mobile base, a support column is arranged on the mobile base, a cavity is provided in the support column, and the lifting-rotation adjustment mechanism is arranged in the cavity.

Further, the lifting rotating bracket also includes a moving base, and also includes a driving mechanism for driving the first driven bevel gear and the second driven bevel gear to lift, and the driving mechanism includes:

The first horizontal drive motor;

a driving gear, the driving gear is arranged at the output end of the first driving motor;

a vertical drive rack, the drive rack meshes with the drive gear;

a first link and a second link arranged at both ends of the drive rack and moving with the drive rack;

The first shaft sleeve rotatably connected with the inner telescopic sleeve and the second shaft sleeve rotatably connected with the external telescopic sleeve, the first shaft sleeve and the second shaft sleeve are respectively connected with the first shaft sleeve on the corresponding side The first connecting rod is fixedly connected with the second connecting rod.

Further, the inner wall of the cavity is longitudinally arranged along the first chute and the second chute, the first connecting rod is slidably arranged in the first chute, and the second connecting rod is slidably arranged in the second chute groove.

Further, the external telescopic sleeve includes a first sleeve and a second sleeve, the first sleeve is fixedly connected to the first driven bevel gear, and the second sleeve is sleeved on the a first sleeve, and the first sleeve is threadedly connected to the second sleeve, and the outer wall of the second sleeve is provided with an anti-rotation restriction to prevent it from rotating.

Further, the built-in telescopic sleeve includes a third sleeve and a fourth sleeve, the fourth sleeve is arranged in the third sleeve, and expands and contracts along the axial direction of the third sleeve, the The fourth sleeve is connected with the second sleeve through a bearing.

Further, the inner wall of the third sleeve is provided with at least one set of guide grooves symmetrically along the longitudinal direction, and the fourth sleeve is provided with guide blocks slidably connected in the guide grooves.

Further, the driving bevel gear, the first driven bevel gear and the second driven bevel gear are provided with the same U-shaped gear frame, and the gear frame is provided with the built-in telescopic sleeve and the external telescopic sleeve Avoidance holes for pipes to pass through.

Further, the driving bevel gear is connected with a second drive motor.

Second aspect:

The present application provides a multimedia device, including the lifting and rotating support and a multimedia device main body, and the multimedia device main body is fixedly installed on the fixed support.

Compared with prior art, the beneficial effect of the present application is:

first:

An elevating and rotating support proposed by the present application is provided with a driving bevel gear and two first driven bevel gears and a second driven bevel gear that can be respectively engaged with it through lifting, and the first driven bevel gear is set The external telescopic sleeve is provided with a built-in telescopic sleeve on the second driven bevel gear, and the built-in telescopic sleeve is installed through the external telescopic sleeve, and the internal telescopic sleeve and the external telescopic sleeve are rotated and matched, thereby utilizing The first driven bevel gear and the second driven bevel gear go up and down alternately to mesh with the driving bevel gear, and the driving bevel gear drives the first driven bevel gear and the second driven bevel gear to rotate respectively to realize the expansion and contraction of the external telescopic sleeve And the rotation of the built-in telescopic sleeve realizes the lifting and rotating operation of the bracket. The control is simple and convenient, and there is no need to manually twist the stretching bracket to realize the rapid adjustment of the bracket, which is practical and convenient.

Second aspect:

This application proposes a multimedia device, which fixes the main body of the multimedia device through a bracket that can be automatically lifted and rotated, so that the height and angle of the main body of the multimedia device can be flexibly and quickly adjusted according to the needs of use, and the adjustment efficiency is improved. It is convenient and practical .

Description of drawings

Fig. 1 is a structural schematic diagram of the lifting and rotating support provided by the embodiment of the present application at a viewing angle;

Figure 2 is an enlarged view of A in Figure 1;

Figure 3 is an enlarged view of B in Figure 2;

FIG. 4 is a schematic structural diagram of a multimedia device provided by an embodiment of the present application at a viewing angle.

Explanation of the numbers in the accompanying drawings:

1-mobile base, 2-bracket column, 3-cavity, 4-driving bevel gear, 5-first driven bevel gear, 6-second driven bevel gear, 7-U-shaped gear rack, 8-first Drive motor, 9-drive gear, 10-drive rack, 11-first connecting rod, 12-second connecting rod, 13-first bushing, 14-second bushing, 15-first chute, 16 -Second chute, 17-Second drive motor, 18-External telescopic sleeve, 1801-First sleeve, 1802-Second sleeve, 19-Guide post, 20-Ear plate, 21-Internal telescopic sleeve Tube, 2101-third casing, 2102-fourth casing, 22-fixing bracket, 23-guiding groove, 24-guiding slider, 25-main body of multimedia equipment, 26-bearing.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relationship between the components in a certain posture (as shown in the drawings). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

In this application, unless otherwise clearly specified and limited, the terms "connection" and "fixation" should be understood broadly, for example, "fixation" can be a fixed connection, a detachable connection, or an integral body; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be an internal communication between two elements or an interaction relationship between two elements, unless otherwise clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes, and cannot be interpreted as indications or hints Its relative importance or implicitly indicates the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In addition, the meaning of "and/or" appearing in the whole text includes three parallel schemes, taking "A and/or B" as an example, including scheme A, scheme B, or schemes that both A and B satisfy. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist , nor within the scope of protection required by the present application.

Referring to the accompanying drawings 1 to 3, the embodiment of the present application provides a lifting and rotating support, including a mobile base 1, a support column 2, a fixed support 22 and a lifting-rotation adjustment mechanism, and the support column 2 is fixed on the mobile base 1 , the lift-rotation adjustment mechanism is arranged in the support column 2, the fixed support 22 is connected with the lift-rotation adjustment mechanism, and the lift-rotation adjustment mechanism is used to realize the lifting and rotation of the fixed support 22.

Specifically:

Referring to Figure 1, the bottom of the mobile base 1 is equipped with universal rollers, which can be used to move the lifting and rotating bracket conveniently. Fixed-point placement of rotating brackets. The support column 2 is welded to the center position of the upper surface of the mobile base 1, the support column 2 is provided with a cavity 3, the cavity opening of the cavity 3 is located at the center of the top of the support column 2, and the lifting-rotation adjustment mechanism is arranged in the cavity 3, And the lift-rotation adjustment mechanism extends from the mouth of the cavity to the outside of the cavity 3 and is connected with the fixed bracket 22 .

In this embodiment, referring to Fig. 1 to Fig. 3, the lift-rotation adjustment mechanism includes a driving bevel gear 4, a first driven bevel gear 5, a second driven bevel gear 6, a built-in telescopic sleeve 21, an external Telescopic sleeve 18, driving mechanism and U-shaped gear frame 7. Wherein, the U-shaped gear frame 7 is fixed on the inner wall of the cavity 3 of the support column 2 through the side plate, and the U-shaped opening side of the U-shaped gear frame 7 is horizontal to the left, and the three wheel frame sides of the U-shaped gear frame 7 are all centered. There is an avoidance through hole, and the driving bevel gear 4 is arranged on the right wheel frame side of the U-shaped gear frame 7, and the driving bevel gear 4 is located inside the U-shaped gear frame 7, and is installed on the right wheel frame side through the wheel shaft rotation. In the hole, the wheel shaft is connected with the U-shaped gear frame 7 bearings, and meanwhile, the end of the wheel shaft is connected with a second drive motor 17 through a coupling transmission, and the second drive motor 17 is used to drive the driving bevel gear 4 to rotate.

Meanwhile, referring to Fig. 1 and shown in Fig. 2, the first driven bevel gear 5 and the second driven bevel gear 6 are also arranged on the inner side of the U-shaped gear carrier 7, and the first driven bevel gear 5 and the second driven bevel gear The bevel gears 6 are set up and down at intervals, and the first driven bevel gear 5 and the second driven bevel gear 6 move up and down synchronously on the drive of the driving mechanism. When the first driven bevel gear 5 and the second driven bevel gear When the bevel gear 6 moves upwards, the second driven bevel gear 6 located below meshes with the driving bevel gear 4, and when the first driven bevel gear 5 and the second driven bevel gear 6 move downwards, the second driven bevel gear located above A driven bevel gear 5 meshes with the driving bevel gear 4 .

In one embodiment, in order to realize the synchronous lifting of the first driven bevel gear 5 and the second driven bevel gear 6, as shown in Figure 2, the drive mechanism includes a first drive motor 8, a drive rack 10, a drive gear 9. The first connecting rod 11, the second connecting rod 12, the first bushing 13 and the second bushing 14, wherein the first drive motor 8 is mounted horizontally inside the cavity 3 and is located on the side of the U-shaped gear frame 7 In the middle position on the left side, the driving gear 9 is fixedly sleeved on the output end of the first driving motor 8 , and the driving rack 10 is arranged longitudinally on the left side of the U-shaped gear frame 7 , and the driving rack 10 and the driving gear 9 are meshed with each other. The upper end of the driving rack 10 is fixedly welded with a first connecting rod 11, and the lower end of the driving rack 10 is fixedly welded with a second connecting rod 12. The first connecting rod 11 and the second connecting rod 12 are arranged in parallel and transversely. The left end of 11 and the left end of the second connecting rod 12 are slidably connected with the first chute 15 and the second chute 16 on the inner wall of the support column 2, the right end of the first connecting rod 11 is fixedly welded with the first bushing 13, and the second connecting rod The right end of 12 is fixedly welded with second axle sleeve 14. Since the external telescopic sleeve 18 is fixedly connected to the first driven bevel gear 5, the built-in telescopic sleeve 21 is fixedly connected to the second driven bevel gear 6, and the first shaft sleeve 13 and the external telescopic sleeve 18 rotate through bearings connected, the second shaft sleeve 14 is rotationally connected with the built-in telescopic sleeve 21 through the bearing 26, so it is conceivable that when the first drive motor 8 rotates in the forward direction, the drive gear 9 meshes with the drive rack 10 to drive the drive rack 10 Move down, so that the first driven bevel gear 5 and the second driven bevel gear 6 move downward through the linkage of the first connecting rod 11, the first bushing 13, the second connecting rod 12 and the second bushing 14, so that The first driven bevel gear 5 meshes with the driving bevel gear 4. Conversely, when the first driving motor 8 rotates in the opposite direction, the driving gear 9 meshes with the driving rack 10, driving the driving rack 10 to move upwards, thereby passing through the first A connecting rod 11, the first bushing 13, the second connecting rod 12 and the second bushing 14 move upward in conjunction with the first driven bevel gear 5 and the second driven bevel gear 6, so that the second driven bevel gear 6 Engaging with the driving bevel gear 4, the first driven bevel gear 5 and the second driven bevel gear 6 move up and down to complete alternate meshing with the driving bevel gear 4.

Furthermore, referring to Fig. 1 to Fig. 3, the external telescopic sleeve 18 is fixed to the first driven bevel gear 5, wherein the external telescopic sleeve 18 includes a first sleeve 1801 and a second sleeve 1802, the second sleeve 1802 The lower end of the casing 1801 avoids passing through the side of the upper wheel frame and is fixedly connected with the first driven bevel gear 5. The rotation of the first driven bevel gear 5 drives the first casing 1801 to rotate, and the first casing 1801 The upper part of the upper part is provided with an external thread, the bottom end of the thread of the second sleeve 1802 is externally connected to the first sleeve 1801, and the top of the second sleeve 1802 can freely protrude from the top cavity of the cavity 3, and the second The outer diameter of the sleeve 1802 is slightly smaller than the opening at the top of the cavity 3, forming a clearance fit to ensure that the second sleeve 1802 protrudes from the opening.

At the same time, the second sleeve 1802 is provided with an anti-rotation limiter. As an embodiment, the anti-rotation limiter includes a pair of guide posts 19 symmetrically arranged on both sides of the second sleeve 1802. The guide posts 19 and the second outer sleeve Parallel, the bottom end of the guide post 19 is fixedly connected to the end surface of the first bushing 13 , the two sides of the second sleeve 1802 are integrally formed with ear plates 20 , and the guide posts 19 respectively pass through the ear plates 20 on the side where they are located. Therefore, it is conceivable that when the first driving bevel gear meshes with the driving bevel gear 4, and the second drive motor 17 drives the driving bevel gear 4 to rotate positively and negatively, the first driving bevel gear rotates synchronously, driving the first casing 1801 to rotate, The relationship between the first sleeve 1801 and the second sleeve 1802 is threaded, and the second sleeve 1802 is restricted by the anti-rotation limiter so that it cannot rotate, so that the second sleeve 1802 can only follow the first sleeve 1801 Do lifts. Of course, in order to prevent the second sleeve 1802 from falling off from the first sleeve 1801 during the ascent process, it is possible to set a mutual limiter on the outside of the top end of the first sleeve 1801 and the inside of the bottom end of the second sleeve 1802. The position of the ring block is used to control the rising stroke of the second bushing 1802.

In addition, the built-in telescopic sleeve 21 includes a third sleeve 2101 and a fourth sleeve 2102, the first sleeve 1801, the second sleeve 1802 and the first driven bevel gear 5 are centrally provided with a through hole along the longitudinal direction, the third The lower end of the sleeve 2101 passes through the inside of the first sleeve 1801 and the inside of the first driven bevel gear 5, and passes down through the avoidance hole on the side of the lower wheel frame of the U-shaped gear frame 7, and the second shaft sleeve 14 is sleeved on the lower end of the third sleeve 2101 through a bearing, the top of the third sleeve 2101 is provided with a sliding cavity, and the fourth sleeve 2102 is slidably arranged in the sliding cavity. At the same time, on both sides of the inner wall of the third sleeve 2101 At least one set of guide grooves 23 are symmetrically provided, and the outer wall of the fourth sleeve 2102 is provided with a guide block that is slidably connected in the guide groove 23. The fourth sleeve 2102 protrudes upward from the top opening of the second sleeve 1802, and It is fixedly welded with the fixed bracket 22, and the fourth sleeve 2102 and the second sleeve 1802 form a rotational connection through the bearing 26 at the top, so it is conceivable that when the second sleeve 1802 stretches, due to the second sleeve 1802 and the second sleeve 1802 The four sleeves 2102 are connected by bearings 26, so the fourth sleeve 2102 will expand and contract synchronously with the second sleeve 1802, thereby realizing the lifting of the fixed bracket 22. At the same time, when the second transmission bevel gear meshes with the driving bevel gear 4, When the second driving motor 17 drives the driving bevel gear 4 to rotate positively and negatively, the driving bevel gear 4 drives the second driven bevel gear 6 to rotate, so that the driven bevel gear drives the third casing 2101 to rotate together with the fourth casing 2102, thereby Realize the rotation of fixed support 22.

To sum up, the working principle of the lifting and rotating support provided in the embodiment of the present application is:

Ascent process:

Through the positive rotation of the first driving motor 8, the driving gear 9 is driven to rotate, and the driving gear 9 drives the engaged driving rack 10 to move downward. During the downward movement of the driving rack 10, the second connecting rod 12 and the second The shaft sleeve 14 drives the second driven bevel gear 6 to move downward, so that the second driven bevel gear 6 is disengaged from the driving bevel gear 4. At the same time, the first connecting rod 11 and the first shaft sleeve 13 drive the first driven bevel gear The driving bevel gear 5 moves downward, so that the first driven bevel gear 5 and the driving bevel gear 4 are engaged;

Then by the forward rotation of the second driving motor 17, the driving bevel gear 4 is driven to rotate, and the driving bevel gear 4 rotates to drive the first driven bevel gear 5 meshed with it to rotate, and the first driven bevel gear 5 rotates to drive and fix it The first bushing 1801 rotates in the forward direction, because the first bushing 1801 and the second bushing 1802 are screwed together, and the second bushing 1802 is restricted by the anti-rotation limiter so that it cannot rotate, so the second bushing 1802 is along the The first bushing 1801 goes up, and because the fourth bushing 2102 is slidably installed in the third bushing 2101, the fourth bushing 2102 is connected with the second bushing 1802 through the bearing 26, so the second bushing 2102 During the upward movement of 1802 , the fourth casing 2102 will rise synchronously with the second casing 1802 , so that the fixing bracket 22 fixed on the top of the fourth casing 2102 will complete the rising.

Conversely, the descent process:

After the first driving bevel gear and the driving bevel gear 4 mesh, the reverse rotation of the second driving motor 17 drives the driving bevel gear 4 to rotate, and the driving bevel gear 4 rotates to drive the first driven bevel gear 5 meshed with it to rotate , the rotation of the first driven bevel gear 5 drives the first bushing 1801 fixed thereto to rotate in reverse, because the first bushing 1801 and the second bushing 1802 are screwed together, and the second bushing 1802 is restricted by the anti-rotation limiter Therefore, the second sleeve 1802 descends along the first sleeve 1801, and because the fourth sleeve 2102 is slidably installed in the third sleeve 2101, the fourth sleeve 2102 is in contact with the second sleeve again. 1802 is connected by the bearing 26, so when the second sleeve 1802 moves downward, the fourth sleeve 2102 will descend synchronously with the second sleeve 1802, so that the fixed bracket 22 fixed on the top of the fourth sleeve 2102 Complete the descent.

Rotation process:

Through the reverse rotation of the first driving motor 8, the driving gear 9 is driven to rotate, and the driving gear 9 drives the engaged driving rack 10 to move upward. During the upward movement of the driving rack 10, the second connecting rod 12 and the second The shaft sleeve 14 drives the second driven bevel gear 6 to move upwards, so that the second driven bevel gear 6 and the driving bevel gear 4 complete meshing. At the same time, the first connecting rod 11 and the first shaft sleeve 13 drive the first driven bevel gear The moving bevel gear 5 moves upward, so that the first driven bevel gear 5 and the driving bevel gear 4 are out of engagement;

Then by starting the second driving motor 17 to rotate, the second driving motor 17 drives the second driven bevel gear 6 to rotate, and the second driven bevel gear 6 rotates to drive the third sleeve pipe 2101 to rotate, because the fourth sleeve pipe 2102 passes through the guide block The sliding embedded in the guide groove 23 of the inner wall of the third sleeve 2101, so the fourth sleeve 2102 will rotate with the rotation of the third sleeve 2101, so that the fixed bracket 22 fixed on the top of the fourth sleeve 2102 rotates synchronously.

Of course, in order to avoid operating the first drive motor 8 and the second drive motor 17, a control panel can be rotated on the front of the support column 2 to control the first drive motor 8 and the second drive motor 17.

It should be noted that: in this embodiment, since the second bushing 1802 and the opening of the cavity 3 of the support column 2 are clearance fit, the first driven bevel gear 5 and the second driven bevel gear 5 are driven by the driving mechanism. The movable bevel gear 6 can realize free lifting movement. In addition, since the fourth bushing 2102 and the second bushing 1802 are rotationally connected by the bearing 26, when the fourth bushing 2102 rotates, the second bushing 1802 will not Rotate accordingly, so as to ensure that the second sleeve 1802 will not move up and down during the rotation of the fourth sleeve 2102 .

Also in this embodiment, the embodiment of the application provides a multimedia device, including the aforementioned lifting and rotating bracket and the multimedia device main body 25, the multimedia device main body 25 is fixedly installed on the fixed bracket 22, between the fixed bracket 22 and the multimedia device main body 25 The wall-mounted form can be used for fixed installation, so that the height and angle of the multimedia device main body 25 can be quickly adjusted by lifting and rotating the bracket, which is convenient and practical.

The above descriptions are only preferred embodiments of the application, and are not intended to limit the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the application shall be included in the protection of the application. within range.

Claims (10)

1. A lifting and rotating bracket, characterized by comprising a fixed bracket (22) and a lifting and rotating adjusting mechanism, wherein the lifting and rotating adjusting mechanism is used for realizing lifting and rotating of the fixed bracket (22);

wherein the lift-rotation adjustment mechanism includes:

a drive bevel gear (4) horizontally arranged;

a first driven bevel gear (5) and a second driven bevel gear (6) which can synchronously move up and down, and the first driven bevel gear (5) and the second driven bevel gear (6) are alternately meshed with the driving bevel gear (4) in the process of lifting;

an external telescopic tube (18) fixed with the first driven bevel gear (5), wherein the first driven bevel gear (5) rotates to realize telescopic adjustment of the external telescopic tube (18);

an internal telescopic tube (21) fixed with the second driven bevel gear (6), wherein the internal telescopic tube (21) synchronously rotates along with the second driven bevel gear (6), the internal telescopic tube (21) is arranged in the external telescopic tube (18) in a penetrating way, and the internal telescopic tube (21) is rotationally connected with the external telescopic tube (18) through a bearing (26);

the fixed support (22) is arranged at the top end of the built-in telescopic tube (21).

2. The lifting rotating bracket according to claim 1, further comprising a movable base (1), wherein a bracket upright (2) is arranged on the movable base (1), a cavity (3) is arranged in the bracket upright (2), and the lifting-rotating adjusting mechanism is arranged in the cavity (3).

3. Lifting swivel bracket according to claim 2, further comprising a drive mechanism for driving the first driven bevel gear (5) and the second driven bevel gear (6) to lift, the drive mechanism comprising:

a first drive motor (8) arranged horizontally;

the driving gear (9), the said driving gear (9) is set up in the output end of the said first driving motor (8);

a drive rack (10) arranged longitudinally, the drive rack (10) being meshed with the drive gear (9);

the first connecting rod (11) and the second connecting rod (12) are arranged at two ends of the driving rack (10) and move along with the driving rack (10);

the telescopic device comprises a first shaft sleeve (13) and a second shaft sleeve (14), wherein the first shaft sleeve (13) is rotationally connected with the built-in telescopic sleeve (21), the second shaft sleeve (14) is rotationally connected with the external telescopic sleeve (18), and the first shaft sleeve (13) and the second shaft sleeve (14) are respectively fixedly connected with the first connecting rod (11) and the second connecting rod (12) on the corresponding sides.

4. A lifting and rotating bracket according to claim 3, characterized in that the inner wall of the cavity (3) is provided with a first sliding groove (15) and a second sliding groove (16) along the longitudinal direction, the first connecting rod (11) is arranged on the first sliding groove (15) in a sliding way, and the second connecting rod (12) is arranged on the second sliding groove (16) in a sliding way.

5. The lifting rotating bracket according to claim 1, wherein the external telescopic sleeve (18) comprises a first sleeve (1801) and a second sleeve (1802), the first sleeve (1801) is fixedly connected with the first driven bevel gear (5), the second sleeve (1802) is sleeved on the first sleeve (1801), the first sleeve (1801) is in threaded connection with the second sleeve (1802), and an anti-rotation limiting piece for preventing rotation of the second sleeve (1802) is arranged on the outer wall of the second sleeve (1802).

6. The lifting and rotating bracket according to claim 5, characterized in that the built-in telescopic sleeve (21) comprises a third sleeve (2101) and a fourth sleeve (2102), the fourth sleeve (2102) is arranged in the third sleeve (2101) and stretches along the axial direction of the third sleeve (2101), and the fourth sleeve (2102) and the second sleeve (1802) are connected through a bearing.

7. The lifting and rotating bracket according to claim 6, characterized in that the inner wall of the third sleeve (2101) is provided with at least one set of guide grooves (23) symmetrically along the longitudinal direction, and the fourth sleeve (2102) is provided with guide blocks which are connected in a sliding manner in the guide grooves (23).

8. Lifting and rotating support according to claim 1, characterized in that the drive bevel gear (4), the first driven bevel gear (5) and the second driven bevel gear (6) are provided with the same U-shaped gear frame (7), which is provided with a relief through hole for the inner telescopic tube (21) and the outer telescopic tube (18) to pass through.

9. Lifting and rotating support according to claim 1, characterized in that the drive bevel gear (4) is connected with a second drive motor (17) in a driving manner.

10. A multimedia device comprising the lifting/lowering swivel stand according to any one of claims 1 to 9 and a multimedia device body (25), the multimedia device body (25) being fixedly mounted to the fixed stand (22).