A stretchable folding table

Abstract

The application relates to a stretchable folding table, belonging to the technical field of furniture, which comprises a hollow table frame, table legs for supporting the table frame, and a first table panel and a second table panel arranged on the table frame, first and second sliding grooves arranged in an upper-lower interval are formed in the table frame, a channel for connecting the first and second sliding grooves is arranged between the first and second sliding grooves, one end of the side surface of the second table panel is provided with a sliding block for passing through the channel, a supporting groove is formed in the side edge of the second table panel, a supporting plate is arranged in the first sliding groove of the table frame, and a driving mechanism for driving the supporting plate to move towards the opening direction of the first sliding groove is arranged in the table frame, the driving mechanism is configured to drive the supporting plate to insert into the supporting groove when the sliding block enters the first sliding groove and the supporting groove is aligned with the supporting plate. The application can improve the bearing capacity of the stretchable folding table when unfolded.

Description

Technical Field

[0001] This application relates to the field of furniture, and in particular to a stretchable folding table. Background Technology

[0002] A table is a common piece of furniture, with a flat surface on top and supports underneath. It can be used to place objects, work, eat, write, etc.

[0003] Traditional desks and office tabletops have fixed sizes, which are sufficient for normal use. However, if there are many people and multiple people need to sit around the table at the same time, the original tabletop size will be insufficient, requiring a larger table. This not only causes waste but also occupies space due to the need to prepare extra tables. Therefore, to facilitate use by multiple people, extendable tables are now available on the market. These typically include a retractable tabletop that can be pulled out when needed.

[0004] As attached Figure 1 The illustrated extendable table includes a table frame 1, table legs 2, a first tabletop 3, and a second tabletop 4. The table legs 2 support the table frame 1. The table frame 1 has two sliding grooves 18, one above the other. In the normal state, the first tabletop 3 and the second tabletop 4 are located within the two sliding grooves 18, respectively. A channel 15 connecting the two sliding grooves 18 is also provided. In the extended state, the first tabletop 3 needs to slide to one side of the upper sliding groove first, and then the second tabletop 4 slides from the lower sliding groove into the upper sliding groove through the channel 15 and then slides to the other side of the upper sliding groove. A slider 41 is provided on the side of the second tabletop 4 to slide within the sliding groove 18.

[0005] Because the second desktop panel 4 needs to be able to move upward through the channel 15, and to ensure the proper separation of the upper and lower sliding grooves, the width of the channel 15 cannot be set too wide. This means that the slider 41 on the side of the second desktop panel 4 cannot be set too large, otherwise it will not be able to pass through the channel 15. Since the second desktop panel 4 is supported by the slider 41, this results in poor load-bearing capacity of the second desktop panel 4. Summary of the Invention

[0006] To improve the stability of the stretchable folding table during use, this application provides a stretchable folding table.

[0007] This application provides a stretchable folding table, which adopts the following technical solution:

[0008] The utility model provides a stretch folding table, including hollow table frame, the table leg for supporting the table frame and the first table panel and second table panel set up on the table frame, the first sliding groove and the second sliding groove are arranged in the upper and lower interval respectively on the table frame, the channel for the first sliding groove and the second sliding groove is arranged between the first sliding groove and the second sliding groove, one end of the second table panel side is provided with the sliding block for through the channel, the side of second table panel is provided with the support groove, the support plate and the drive mechanism for driving support plate to move to the first sliding groove opening direction are provided in the first sliding groove of the table frame, the drive mechanism is configured to drive the support plate inserts into the support groove when the sliding block enters the first sliding groove and the support groove is aligned with the support plate.

[0009] By adopting the above technical scheme, in the normal state, the first table panel and the second table panel are located in the first sliding groove and the second sliding groove respectively, at this time, the second table panel is hidden below the first table panel; in the unfolded state of the folding table unfolded from the normal state, first, the first table panel is slid to the side of the first sliding groove, then the second table panel is slid in the second sliding groove to the side opposite to the first table panel, and the sliding block is aligned with the channel, then the second table panel is controlled to enter the first sliding groove through the channel, the support plate is controlled to insert into the support groove of the second table panel by the drive mechanism, the second table panel can be supported by the support plate, so that the second table panel is not only supported by the sliding block as a support point in the unfolded state, and the load-bearing effect of the second table panel can be improved.

[0010] Optionally, the drive mechanism comprises a driving block arranged in the first sliding groove and a linkage assembly connected between the driving block and the support plate, the linkage assembly is configured to drive the support plate to move to the opening direction of the first sliding groove when the sliding block abuts against the driving block and drives the driving block to move away from the support plate.

[0011] By adopting the above technical scheme, by the arrangement of the driving block, after the second table panel enters the first sliding groove through the channel, the second table panel slides to the side close to the first table panel, at this time, the sliding block can abut against the driving block and push the driving block to move away from the support plate, then under the driving of the linkage assembly, the support plate can extend from the first sliding groove and enter the support groove of the second table panel.

[0012] Optionally, the linkage assembly comprises a linkage block arranged on the side of the support plate away from the opening of the first sliding groove, the linkage block and the driving block are connected through a traction rope, the support plate is provided with a guide block on the side away from the support plate, the guide block has an inclined guide surface and is used for converting the transverse pushing force of the linkage block into the driving force of the support plate moving to the opening direction of the first sliding groove.

[0013] By adopting the technical scheme, the linkage block moves synchronously with the driving block under the action of the traction rope, so that the linkage block and the guide block are lowered, and the linkage block can drive the support plate to move to the direction of the notch of the first sliding groove and enter the support groove of the second tabletop plate under the action of the inclined surface of the guide block.

[0014] Optionally, the linkage block has an inclined surface for abutting against the inclined surface.

[0015] By adopting the technical scheme, the contact area between the linkage block and the guide block can be increased, and the stability of the linkage block when driving the guide block to move can be improved.

[0016] Optionally, the linkage assembly is further provided with a reset tension spring, one end of the reset tension spring is connected to the groove bottom of the first sliding groove, and the other end of the reset tension spring is connected to the support plate.

[0017] By adopting the technical scheme, under the action of the reset tension spring, when the driving block is not pushed by the sliding block, the reset tension spring can drive the support plate to reset, so that the support plate is retracted into the first sliding groove, thereby not affecting the normal sliding of the first tabletop plate.

[0018] Optionally, the linkage assembly further comprises a reset spring, the reset spring is arranged outside the traction rope, one end of the reset spring abuts against the linkage block, and the first sliding groove is provided with an abutting plate for the other end of the reset spring to abut between the linkage block and the driving block, and the abutting plate has a through hole for the traction rope to pass through.

[0019] By adopting the technical scheme, when the driving block is not pushed by the sliding block, the reset spring drives the linkage block to reset, and the traction rope drives the driving block to reset, thereby not affecting the normal sliding of the first tabletop plate.

[0020] Optionally, the bottom of the second tabletop plate is provided with a foldable support plate, the table leg is provided with an abutting plate for the support plate to abut, and in the unfolded state, the support plate abuts against the abutting plate to limit the sliding of the second tabletop plate.

[0021] By adopting the technical scheme, in the unfolded state, the support plate abuts against the abutting plate, thereby improving the stability of the second tabletop plate when in use.

[0022] Optionally, the abutting plate is rotationally arranged on the table leg, and the rotation connection point between the abutting plate and the table leg is located at the upper end of the abutting plate.

[0023] By adopting the technical scheme, the support plate is first rotated out, and then the abutting plate is rotated out for the support plate to abut, thereby avoiding the interference of the abutting plate on the rotation of the support plate.

[0024] Optionally, the first sliding groove is further provided with a positioning block, the positioning block is located on the side of the first sliding groove away from the support plate, and the first tabletop panel is provided with a positioning groove through which the positioning block passes and slides.

[0025] By adopting the above technical scheme, the positioning block and the positioning groove can cooperate to improve the supporting force of the first tabletop panel, and the positioning block can cooperate with the positioning groove without affecting the normal sliding of the first tabletop panel in use.

[0026] Optionally, the sliding block is a cylindrical block, the middle part of the side surface of the second tabletop panel is provided with a turning column, a diagonal channel communicating the first sliding groove and the second sliding groove is arranged between the first sliding groove and the second sliding groove, the diagonal channel is arranged in a spaced manner with the channel, the turning column can enter the first sliding groove from the second sliding groove through the diagonal channel, and when the turning column abuts against the end part of the first sliding groove, the sliding block is aligned with the channel and can enter the first sliding groove through the channel along with the rotation of the second tabletop panel.

[0027] By adopting the above technical scheme, the turning column on the second tabletop panel can first enter the first sliding groove through the diagonal channel, and the sliding block can enter the first sliding groove by rotating, thereby avoiding the process of vertically moving the second tabletop panel, so as to facilitate the second tabletop panel to enter the first sliding groove.

[0028] In summary, the present application has at least one of the following beneficial technical effects:

[0029] 1. In the unfolded state, the support block is inserted into the support groove of the second tabletop panel, thereby improving the load-bearing capacity of the second tabletop panel;

[0030] 2. The turning column cooperates with the diagonal channel, and in the process of unfolding the second tabletop panel, the second tabletop panel can be directly slid transversely, after the turning column enters the first sliding groove through the diagonal channel, the turning column abuts against one side of the first sliding groove, and the second tabletop panel can be directly rotated to make the sliding block enter the first sliding groove through the channel. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic view of the stretchable folding table in normal use.

[0032] Figure 2 is an exploded view of the existing stretchable folding table when unfolded.

[0033] Figure 3 is a schematic view of the stretchable folding table in normal use in the embodiment of the present application.

[0034] Figure 4 is a structural schematic view of the table frame and the table leg in the embodiment of the present application.

[0035] Figure 5 This is a schematic diagram of the structure of the second tabletop in the embodiments of this application.

[0036] Figure 6 This is a schematic diagram of the unfolded folding table in an embodiment of this application.

[0037] Figure 7 yes Figure 6 Sectional view at point AA.

[0038] Figure 8 yes Figure 7 Enlarged view of point A in the middle.

[0039] Explanation of reference numerals in the attached drawings: 1. Table frame; 11. Main side plate; 12. Secondary connecting rod; 13. First slide groove; 131. Positioning block; 14. Second slide groove; 15. Channel; 16. Angled channel; 17. Support plate; 171. Guide block; 172. Angled guide surface; 173. Return spring; 2. Table leg; 3. First tabletop; 31. Positioning groove; 4. Second tabletop; 41. Slider; 42. Steering column; 43. Support groove; 44. Support plate; 5. Drive mechanism; 51. Drive block; 52. Linkage assembly; 521. Linkage block; 522. Traction rope; 523. Return spring; 524. Abutment plate. Detailed Implementation

[0040] The following is in conjunction with the appendix Figures 3-8 This application will be described in further detail.

[0041] This application discloses a stretchable folding table.

[0042] Reference Figure 3 A stretchable folding table includes a table frame 1, table legs 2 supporting the table frame 1, and a first tabletop 3 and a second tabletop 4 mounted on the table frame 1. In normal use, the first tabletop 3 is positioned above the second tabletop 4, concealing the second tabletop 4 and reducing space occupancy. When unfolded, the first tabletop 3 and the second tabletop 4 are symmetrically distributed on both sides of the table frame 1, increasing the usable area and accommodating more users.

[0043] Specifically, refer to Figure 4 The table frame 1 is a hollow frame structure with two opposing main side panels 11 and three secondary connecting rods 12. The horizontal height of the main side panels 11 is higher than the height of the secondary connecting rods 12. The first tabletop 3 and the second tabletop 4 are both connected between the two main side panels 11. The three secondary connecting rods 12 connect the two main side panels 11 together and are located at both ends and the middle of the main side panels 11, respectively. The table legs 2 are four in number and are located at the four corners of the frame structure.

[0044] Reference Figure 3 and Figure 4The two main side panels 11 have a first sliding groove 13 and a second sliding groove 14 spaced vertically apart on their opposite sides. During normal use, the first tabletop 3 and the second tabletop 4 are located in the first sliding groove 13 and the second sliding groove 14, respectively, and the second tabletop 4 is hidden at this time.

[0045] Reference Figure 4 and Figure 5 A channel 15 is provided between the first slide 13 and the second slide 14 to connect the two. A slider 41 is provided at one end of the side of the second desktop plate 4, which can pass through the channel 15. The second desktop plate 4 passes through the channel 15 via the slider 41 and then enters the first slide 13.

[0046] Reference Figure 3 , Figure 4 and Figure 5 In other embodiments of this application, a steering column 42 is provided in the middle of the side of the second desktop panel 4, and an inclined channel 16 connecting the first slide groove 13 and the second slide groove 14 is also provided between them. The inclined channel 16 is spaced apart from the channel 15. Both the steering column 42 and the slider 41 are cylindrical. After the first desktop panel 3 slides to the end of the first slide groove 13 away from the inclined channel 16, the steering column 42 slides into the first slide groove 13 through the inclined channel 16. At this time, the second desktop panel 4 will tilt as the steering column 42 slides. After the steering column 42 enters the first slide groove 13 through the inclined channel 16, the steering column 42 is moved to the end of the first slide groove 13 in the original direction of movement. At this time, the slider 41 is aligned with the channel 15, and the slider 41 is slightly smaller than the width of the channel 15 so that when the second tabletop 4 is pressed, the slider 41 enters the first slide groove 13 through the channel 15. Then, the second tabletop 4 is controlled to slide towards the side closer to the first tabletop 3 and abut against the first tabletop 3. At this time, the slider 41 and the steering column 42 are not aligned with the channel 15 and the inclined channel 16, but fall into the first slide groove 13 and abut against the bottom of the first slide groove 13 to support the second tabletop 4.

[0047] To enhance support for the second desktop board 4, in some other embodiments of this application, see Figure 6. Figure 7 and Figure 8 The second desktop panel 4 has a support groove 43 on its side. The table frame 1 has a support plate 17 installed in the first slide groove 13, and a drive mechanism 5 for moving the support plate 17 toward the opening of the first slide groove 13. The drive mechanism 5 is configured to drive the support plate 17 to insert into the support groove 43 after the second desktop panel 4 enters the first slide groove 13 and the support groove 43 is aligned with the support plate 17. By inserting the support plate 17 into the support groove 43, part of the support plate 17 is located in the first slide groove 13 and part is located in the support groove 43, thereby supporting the second desktop panel 4 and increasing the support area of ​​the second desktop panel 4.

[0048] Reference Figure 4 and Figure 8 The drive mechanism 5 specifically includes a drive block 51 disposed in the first slide groove 13 and a linkage component 52 connected between the drive block 51 and the support plate 17. The drive block 51 is disposed on the side of the channel 15 and is located on the side of the channel 15 away from the inclined channel 16. After the slider 41 enters the first slide groove 13, the second desktop plate 4 moves towards the first desktop plate 3, and the slider 41 can abut against the drive block 51. The linkage component 52 can convert the lateral movement force of the drive block 51 into the driving force of the support plate 17 moving towards the opening of the first slide groove 13, thereby extending out of the opening of the first slide groove 13 and entering the support groove 43.

[0049] Reference Figure 8 The linkage component 52 includes a linkage block 521 disposed on the side of the support plate 17 facing away from the opening of the first slide groove 13. The linkage block 521 is connected to the drive block 51 by a traction rope 522. Therefore, when the drive block 51 is controlled by the slider 41 to move, it will drive the linkage block 521 to move synchronously. A guide block 171 is disposed on the side of the support plate 17 facing away from the support plate 17. The guide block 171 has an inclined guide surface 172. When the drive block 51 drives the linkage block 521 to move synchronously, the linkage block 521 will abut against the inclined guide surface 172, thereby driving the support plate 17 to move towards the groove opening of the first slide groove 13. Furthermore, in order to improve the stability when the linkage block 521 and the guide block 171 are engaged, the linkage block 521 also has an inclined surface. During the process of the linkage block 521 abutting against the guide block 171, the inclined surface can cooperate with the inclined guide surface 172 to improve the stability when the linkage block 521 and the guide block 171 are in contact and driven.

[0050] It should be noted that since the support plate 17 needs a process to slide out from the opening of the first slide groove 13, and the second desktop plate 4 also needs to slide within the first slide groove 13 during this process, the length of the support groove 43 is greater than the length of the support plate 17 in order for the support plate 17 to cooperate with the support groove 43. After the support plate 17 extends out of the first slide groove 13, it can fall directly into the support groove 43, and the continued sliding of the second desktop plate 4 will not affect the cooperation between the support plate 17 and the support groove 43. At the same time, in order to ensure that the sliding of the support plate 17, the drive block 51, and the linkage block 521 does not deflect, corresponding guide rails are provided at the upper and lower ends of the first slide groove 13 to ensure normal sliding. The upper and lower guide rails are not shown in the figure.

[0051] In addition, in order to achieve the reset of the support plate 17 and ensure its use under normal conditions, a reset spring 173 is also connected to one side of the support plate 17 where the guide block 171 is provided. Two reset springs 173 are provided and are respectively provided at both ends of the support plate 17. One end of the reset spring 173 is connected to the guide block 171, and the other end is connected to the bottom of the first slide groove 13.

[0052] A return spring 523 is also provided between the linkage block 521 and the drive block 51. The return spring 523 is wrapped around the outside of the traction rope 522 to avoid interference with the traction rope 522. One end of the return spring 523 abuts against the linkage block 521. An abutment plate 524 is also provided between the drive block 51 and the linkage block 521 for the other end of the return spring 523 to abut against. The abutment plate 524 has a through hole for the traction rope 522 to pass through, so as not to affect the connection between the traction rope 522 and the linkage block 521 and the drive block 51.

[0053] Furthermore, due to the presence of the return spring 523 and the return tension spring 173, the drive block 51 applies a reverse force to the slider 41, thereby affecting the stability of the fit between the support plate 17 and the support groove 43. Therefore, a positioning component is also provided on the second desktop plate 4, which can position the second desktop in the unfolded state.

[0054] Looking back Figure 4 and Figure 6 Specifically, the positioning component includes a support plate 44 rotatably connected to the bottom of the second desktop panel 4. A damping sleeve is fitted on the pivot between the support plate 44 and the bottom of the second desktop panel 4 to increase friction during rotation, so that the support plate 44 will not rotate naturally without external force. The table leg 2 is provided with an abutment plate 524 for the support plate 44 to abut against. In the unfolded state, the support plate 44 abuts against the abutment plate 524, thereby restricting the second desktop panel 4 from moving back under the action of the return spring 523 and the return tension spring 173.

[0055] Furthermore, table legs 2 are located at both ends of the secondary connecting rod 12. Table legs 2 are provided with mounting grooves 21 for the abutment plate 524 to rotate. The abutment plate 524 is rotatably connected to the upper end of the mounting groove 21. A tension spring 22 is connected to the other end of the abutment plate 524, and the tension spring 22 is connected to the upper end of the mounting groove 21. When the abutment plate 524 is in a vertical position, both the tension spring 22 and the abutment plate 524 are vertical, without affecting the placement of the abutment plate 524. When the abutment plate 524 is flipped out to a horizontal position, the tension spring 22 provides tension to the abutment plate 524, thereby preventing the abutment plate 524 from falling. Based on the above scheme, when the second tabletop 4 slides to the unfolded state, the support plate 44 is first flipped out, and then the abutment plate 524 is flipped upwards so that the support plate 44 and the abutment plate 524 abut against each other to form support.

[0056] Finally, refer to Figure 4and Figure 6 To improve the supporting capacity of the first desktop panel 3 without affecting its interference with the drive block 51 during sliding, positioning grooves 31 are provided on both sides of the first desktop panel 3. A positioning block 131 is also provided within the first sliding groove 13. The positioning grooves 31 are arranged along the length of the first desktop panel 3, and the positioning block 131 can slide within the positioning grooves 31. In the unfolded state, the first desktop panel 3 slides to one side of the table frame 1, and the positioning block 131 is located within the positioning groove 31 and abuts against the side wall of the positioning groove 31.

[0057] The implementation principle of a stretchable folding table according to an embodiment of this application is as follows:

[0058] During normal use, the first desktop panel 3 and the second desktop panel 4 are distributed vertically on the table frame 1, and the second desktop panel 4 is hidden. At this time, the sides of the first desktop panel 3 and the second desktop panel 4 are provided with fasteners that connect the first desktop panel 3 and the second desktop panel 4 vertically. The fasteners are not shown in the figure. Since the first desktop panel 3 and the second desktop panel 4 can only slide in opposite directions, the first desktop panel 3 and the second desktop panel 4 can be kept in place.

[0059] When unfolding is required, the first desktop panel 3 is first slid to the side of the table frame 1. Due to the constraints of the positioning block 131 and the positioning groove 31, it can only slide to one side. Then, the second desktop panel 4 is controlled to slide to the other side. The rotating column first enters the first slide groove 13 through the inclined channel 16. The slider 41 rotates upwards into the first slide groove 13. When the slider 41 enters the first slide groove 13, there is still a gap between the second desktop panel 4 and the first desktop panel 3. At this time, the second desktop panel 4 is controlled to move towards the first desktop panel 3. The slider 41 abuts against the drive block 51 and drives the drive block 51 to move. The support plate 17 can extend from the first slide groove 13 and enter the support groove 43 of the second desktop panel 4 to improve the stability of the second desktop panel 4. The support plate 44 at the bottom of the second desktop panel 4 flips downwards, and at the same time, the abutment plate 524 on the table leg 2 flips out to support the support plate 44, completing the unfolding of the stretch folding table.

[0060] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. For example, the drive mechanism 5 can also be driven manually, and the linkage component 52 can be replaced by a gear and rack mechanism for transmission. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A stretchable folding table, characterized in that: The table includes a hollow table frame (1), table legs (2) for supporting the table frame (1), and a first tabletop (3) and a second tabletop (4) mounted on the table frame (1). The table frame (1) is provided with a first sliding groove (13) and a second sliding groove (14) arranged at intervals. A channel (15) is provided between the first sliding groove (13) and the second sliding groove (14) to connect the first sliding groove (13) and the second sliding groove (14). One end of the side of the second tabletop (4) is provided with a channel (15) for passage. The slider (41) of the slide (15) has a support groove (43) on the side of the second desktop plate (4). The table frame (1) has a support plate (17) and a drive mechanism (5) for driving the support plate (17) to move in the direction of the opening of the first slide (13) in the first slide (13). The drive mechanism (5) is configured to drive the support plate (17) to insert into the support groove (43) after the slider (41) enters the first slide (13) and the support groove (43) is aligned with the support plate (17). The driving mechanism (5) includes a driving block (51) disposed in the first slide groove (13) and a linkage component (52) connected between the driving block (51) and the support plate (17). The linkage component (52) is configured to drive the support plate (17) to move toward the opening direction of the first slide groove (13) when the slider (41) abuts against the driving block (51) and drives the driving block (51) to move away from the support plate (17). The linkage assembly (52) includes a linkage block (521) disposed on the side of the support plate (17) facing away from the opening of the first slide groove (13). The linkage block (521) is connected to the drive block (51) by a traction rope (522). The side of the support plate (17) facing away from the support plate (17) is provided with a guide block (171) for the linkage block (521) to abut against. The guide block (171) has an inclined guide surface (172) and is used to convert the lateral thrust of the linkage block (521) into a driving force for the support plate (17) to move towards the opening of the first slide groove (13). The linkage block (521) has an inclined surface for abutting against the inclined guide surface (172). The linkage assembly (52) also includes a return spring (173). One end of the return spring (173) is connected to the bottom of the first slide groove (13), and the other end is connected to the support plate (17). The linkage assembly (52) further includes a return spring (523), which is wound around the traction rope (522). One end of the return spring (523) abuts against the linkage block (521). An abutment plate (524) is provided in the first groove (13) between the linkage block (521) and the drive block (51) for the other end of the return spring (523) to abut against. The abutment plate (524) has a through hole for the traction rope (522) to pass through. The first slide (13) is also provided with a positioning block (131). The positioning block (131) is located on the side of the first slide (13) away from the support plate (17). The first desktop plate (3) is provided with a positioning groove (31) for the positioning block (131) to pass through and slide.

2. A stretchable folding table according to claim 1, characterized in that: The bottom of the second desktop panel (4) is provided with a foldable support plate (44), and the table leg (2) is provided with an abutment plate (524) for the support plate (44) to abut against. In the unfolded state, the support plate (44) abuts against the abutment plate (524) to restrict the sliding of the second desktop panel (4).

3. A stretchable folding table according to claim 2, characterized in that: The abutment plate (524) is rotatably mounted on the table leg (2), and the rotatable connection point between the abutment plate (524) and the table leg (2) is located at the upper end of the abutment plate (524).

4. A stretchable folding table according to claim 1, characterized in that: The slider (41) is a cylindrical block. A steering column (42) is provided in the middle of the side of the second desktop plate (4). An inclined channel (16) is provided between the first slide groove (13) and the second slide groove (14) to connect the first slide groove (13) and the second slide groove (14). The inclined channel (16) is spaced apart from the channel (15). The steering column (42) can enter the first slide groove (13) from the second slide groove (14) through the inclined channel (16). When the steering column (42) abuts against the end of the first slide groove (13), the slider (41) is aligned with the channel (15) and can enter the first slide groove (13) through the channel (15) as the second desktop plate (4) rotates.

Images