WO2021196844A1

WO2021196844A1 - Lower folding mechanism of child game bed

Info

Publication number: WO2021196844A1
Application number: PCT/CN2021/073967
Authority: WO
Inventors: 茅鸿勇
Original assignee: 安徽酷豆丁科技发展股份有限公司
Priority date: 2020-03-31
Filing date: 2021-01-27
Publication date: 2021-10-07
Also published as: CN111419038B; CN111419038A

Abstract

Disclosed is a lower folding mechanism of a child game bed. The lower folding mechanism comprises a base, a connecting rod and a swinging block, wherein the swinging block is arranged in an inner cavity of the lower portion of the base in a swingable manner; the connecting rod is composed of an upper connecting rod and a lower connecting rod; one end of the upper connecting rod and one end of the lower connecting rod are respectively rotationally connected to corresponding positions of a frame body; the other end of the upper connecting rod is rotatably connected to the base; the other end of the lower connecting rod is rotationally connected to the base; the end of the lower connecting rod that extends into the inner cavity of the lower portion of the base is linked with the swinging block; the swinging block is provided with a transmission roller capable of abutting against the end of the lower connecting rod and pushing the swinging block to swing to the left, and a connection shaft capable of connecting to a pull rope; a swinging shaft is arranged at the lower portion of the swinging block on the lower left portion of a lower shaft pin; and the connection shaft, which is connected to the pull rope, is fixed on the left side of the swinging shaft. The lower folding mechanism of the present invention has the advantages of having a clever and firm structure, being flexible and convenient to use and a low production cost.

Description

Lower folding mechanism of children's play bed

Technical field

The invention relates to the technical field of making children's beds, in particular to a lower folding mechanism for children's play beds.

Background technique

The applicant’s original Chinese invention patent application with the application number CN201810225905.7 titled "Lower Folding Device for Children's Play Bed" discloses a lower folding device for children's play bed, including the legs of the bed and one end corresponding to the central controller. The upper link and the lower link are movably connected in position. The other ends of the upper link and the lower link are respectively movably connected to the corresponding positions at the bottom of the bed leg. The structure of the lower link and the bed leg movably connected is: The lower link extends into the cavity of the bed leg and is connected to the middle of the transverse shaft pin. The upper connecting rod is symmetrically arranged on both sides of the concave cavity of the bed leg, and the upper connecting rod is movably connected with the lower connecting rod close to the transverse shaft pin through the connecting rod. Its advantages are: the central controller can be deployed in position when the support bar is in a high position, the bed body is easy to expand, the end of the lower link is guided by the geometric shape of the curved chute, and the bottom of the bed leg is in turn affected by the transverse shaft pin. With a limit function, the curved chute restricts the position change trajectory of the bottom of the bed leg and the deflection angle of the top of the bed leg relative to the central controller. However, the disadvantage is that the lower folding device is more complicated. In order to realize the process of tilting the legs outward and returning to the vertical state, a curved chute needs to be opened, which is inconvenient to produce and the production cost is high, so its structure is still Needs to be improved.

Summary of the invention

The technical problem to be solved by the present invention is to provide a lower folding mechanism of a children's play bed with ingenious structure, firm structure, flexible and convenient use, and low production cost in view of the above-mentioned current state of the art.

The technical solution adopted by the present invention to solve the above technical problems is: the lower folding mechanism of the children's play bed includes a base connected to the bottom of each bed leg, one end can be movably connected with the base, and the other end can be folded and unfolded with the middle of the bed bottom. The connecting rod movably connected to the folding driving device of the body is characterized in that: the lower folding mechanism further comprises a swing block arranged in the inner cavity of the base that can pull the rope, and the swing block is swingably arranged on the base through a swing shaft. In the lower cavity of the foldable drive device, the connecting rod movably connected to each base is composed of an upper connecting rod and a lower connecting rod arranged up and down. Position rotation connection, the other end of the upper link extends into the upper cavity of the base and is rotatably connected with the base by an upper shaft pin, and the other end of the lower link extends into the lower part of the base The cavity is rotationally connected with the base by a lower shaft pin, and the end of the lower link extending into the lower cavity of the base is linked with the swing block, and the lower shaft pin is arranged in the inner cavity of the base at the upper right position of the swing block , The swing block is provided with a drive roller that can be in contact with the end of the lower link and can push the swing block to swing to the left, and a connecting shaft that can be connected with the pull rope, and the swing shaft is arranged on the lower shaft pin In the lower left position of the swing block, the connecting shaft connected with the draw rope is fixed on the left side of the swing shaft.

As an improvement, the swing block is an integral structure formed by symmetrically connecting two fan-shaped swinging pieces. The middle part between the two swinging pieces is fixed together by a swinging piece connecting column. The cavity formed between two swinging pieces.

In a further improvement, the transmission roller and the connecting shaft are respectively located in the cavity of the swing block, and the end of the lower link in the inner cavity of the base extends into the cavity of the swing block, and extends into the lower part of the cavity of the swing block. The end of the connecting rod is an arc-shaped end. When the children’s play cot is fully deployed and the other end of the lower connecting rod is moved down to the lowest end, the bottom end of the arc-shaped end of the lower connecting rod is supported together with the drive roller. When the children’s play bed is gradually retracted and folded, the arc-shaped end of the lower link moves around the drive roller away from the shaft of the drive roller until the frame moves up to the highest end. The drive rollers are supported together.

In a further improvement, the transmission roller is composed of a positioning shaft pin pierced and connected to two swinging pieces and a transmission wheel rotatably sleeved on the positioning shaft pin in the inner cavity of the swing block. The side wall of the transmission wheel can be It is in contact with the arc end; the two ends of the connecting shaft are respectively inserted and fixed on two swinging pieces arranged in parallel on the left and the right, the pull rope is connected with the loop, and the loop is sleeved on the connecting shaft superior.

As an improvement, the bottom of the base is provided with rollers that facilitate the movement of the legs of the bed back and forth.

As an improvement, the folding driving device includes a frame that can move up and down relative to the legs of the bed, a guide rod that is vertically fixed in the middle of the frame and extends downward from the middle of the bottom surface of the frame, and a guide rod that can move up and down along the guide rod. The sliding seat, the other end of the upper connecting rod and the lower connecting rod movably connected with each bed leg are respectively connected to the corresponding position of the frame body through the upper rotating shaft pin and the lower rotating shaft pin. Corresponding to the movable connection of the lower connecting rod, the lower end of the transmission rod is connected to the corresponding side of the sliding seat by the lower transmission pin, and the upper end of the transmission rod is connected to the lower connecting rod by the upper transmission shaft pin. When the children’s play cot is fully unfolded, the upper drive shaft pin is located on the connecting line between the upper turning shaft pin and the lower drive pin, or the upper drive shaft pin is located above or above the connecting line between the upper turning shaft pin and the lower drive pin. Below.

In a further improvement, the frame is also provided with a locking mechanism that can maintain the unfolded state when the bed body is fully expanded. The locking mechanism includes an unlocking rod and a locking piece. The unlocking rod can be moved up and down on the guide rod In the inner cavity, the center of the frame body is provided with a vertical through hole penetrating up and down, the guide rod is inserted and fixed in the vertical through hole of the frame body, and the top surface of the guide rod is flush with the top surface of the frame body , And the lower end of the guide rod extends downward from the bottom surface of the frame body, an unlocking structure of the unlocking rod is provided on the top surface of the frame body, and the locking piece is located in the inner cavity of the unlocking rod. When the device is moved down to the lowest position to fully unfold the bed, the locking piece can be locked by supporting the bottom surface of the sliding seat through the unlocking rod and the corresponding side of the guide rod. When the bed needs to be folded and unlocked, it passes through The unlocking structure drives the locking piece to retract into the inner cavity of the unlocking rod to be separated from the sliding seat, so that the sliding seat can be moved downward to be unlocked.

As an improvement, the locking piece is located in the lower cavity of the unlocking lever, and the locking piece is composed of at least two positioning pieces. The lower part of each positioning piece is provided with a connecting hole for inserting the horizontal pin, and the positioning piece above the connecting hole It is provided with oblique strip-shaped holes, the positioning piece is folded together like a folding fan, and the lower part of the positioning piece is inserted through the connecting hole through a horizontal shaft pin so that the positioning piece can be unfolded and folded left and right like a folding fan. The left and right ends of the pin are respectively fixed on the left and right corresponding sides of the lower part of the guide rod. A folding pull shaft that can move up and down in the oblique strip hole to unfold and fold the positioning piece is inserted in the oblique strip hole. The folding pull The left and right ends of the shaft are radially fixed on the left and right sides corresponding to the unlocking rod. The unlocking rod is provided with a notch that extends out of the side of the unlocking rod when the positioning piece is expanded left and right, and the left and right sides of the guide rod corresponding to the notch are provided. The side faces are also respectively provided with through cavities through which the positioning piece passes through the gap when it is unfolded and then extends out of the side of the guide rod. The top surface of the positioning piece that extends through the cavity can be supported together with the bottom surface of the sliding seat. Vertical waist-shaped holes are respectively opened on the left and right sides, and a fixed shaft pin is inserted radially in the waist-shaped hole. The left end of the fixed shaft pin passes through the left side of the unlocking lever and is fixed to the corresponding left side of the guide rod. , The right end of the fixed shaft pin passes through the right side of the unlocking rod and is fixed together with the corresponding right side of the guide rod. The inner cavity of the unlocking rod above the notch is provided with a return spring, and the bottom of the return spring is above the notch The support part in the inner cavity of the unlocking lever is supported, and the upper end of the return spring can be in contact with the fixed shaft pin and supported together. The upper and lower hole distance of the waist-shaped hole is larger than that of the folding shaft The maximum distance after the positioning sheet is completely folded.

In a further improvement, the unlocking structure includes a pull ring and a pull rope body. When the pull ring is selected, the two ends of the pull ring are connected with a rotatably pulling shaft connected to the top surface of the unlocking rod.

In a further improvement, the top of the frame body is connected with a pull portion capable of pulling the frame body upward, and the unlocking structure is the pressing extension end of the unlocking rod extending out of the vertical through hole or the top surface of the unlocking rod being opposite to the top surface of the vertical through hole. Press the flush end flush, the locking piece is located in the lower cavity of the unlocking rod, the locking piece is composed of at least two positioning pieces, and the upper part of each positioning piece is provided with a connecting hole for inserting a horizontal pin, which is connected The positioning piece below the hole is provided with an oblique strip hole, the positioning piece is folded together like a folding fan, the upper part of the positioning piece is inserted together through the connecting hole through a horizontal pin, so that the positioning piece can be unfolded and folded left and right like a folding fan , The left and right ends of the horizontal shaft pin are respectively fixed on the left and right corresponding sides of the upper part of the guide rod, and a folding pull shaft that can move up and down in the diagonal hole to expand and fold the positioning piece is inserted in the diagonal strip hole , The left and right ends of the folding pull shaft are radially fixed on the left and right sides corresponding to the unlocking rod, and the unlocking rod is provided with a notch that can extend out of the side of the unlocking rod when the positioning piece is unfolded left and right, and guides corresponding to the position of the notch The left and right sides of the rod are also respectively provided with a through cavity through which the positioning piece passes through the gap when it is unfolded and then extends out of the side of the guide rod. The buckle surface of the positioning piece that extends out of the through cavity can be buckled together with the bottom surface of the sliding seat and is located in the middle of the unlocking lever. The left and right sides of the unlocking rod at the upper part of the inner cavity are respectively provided with vertical waist-shaped holes, the horizontal shaft pin is radially penetrated in the waist-shaped holes, and a return spring is provided in the inner cavity of the guide rod below the through cavity, The upper end of the return spring is in contact with the unlocking rod, and the lower end of the return spring is supported by the support rod located in the inner cavity of the guide rod, and the upper and lower hole distance of the waist-shaped hole is larger than the upper and lower holes of the folding pull shaft Move to the maximum distance after the positioning piece is fully folded. After pressing the top of the unlocking lever, the locking piece is retracted into the inner cavity of the unlocking lever and separated from the sliding seat. The upward pulling part can move the sliding seat downward to unlock.

Compared with the prior art, the present invention has the advantage that the folding and unfolding of the lower part of the children’s play bed is realized by the folding driving device and the swinging block, and the folding driving device and the swinging block are linked by a connecting rod, and the connecting rod and the swinging block are both Rigid structure with simple motion trajectory, and the linkage method is rolling friction, so the transmission efficiency is high and not easy to be damaged; the linkage between the swing block and the lower link converts the complex movement of the link pulling the rope into the lower link end drive swing block Swing; when the children’s folding bed is fully unfolded, the top of the drive roller touches the lower arc surface of the arc-shaped end of the lower link, and the drive roller locks the lower link to prevent the frame from arching and the entire bottom frame Flat; the four-link mechanism is formed by cleverly designing the connection position of the upper link and the lower link, so that when the children's play bed is unfolded, the legs of the bed can first tilt outward and then return to the vertical movement track, which can be divided into details It is a two-stage unfolding process. When the bed body is just unfolded, the unfolding amplitude of the upper end of the bed leg is greater than the unfolding amplitude of the lower end of the bed leg. When the bed body continues to expand, the lower end of the bed leg continues to expand to the upper end of the bed leg, and the bed leg returns to the vertical normal state of use, realizing the complete expansion of the bed body. The design of the mechanism is helpful for the deployment of the guard bar, and then realizes the opening and closing of the play crib by a single person; because of the ingenious design of the connecting rod connection structure, the children’s play crib has the above two different legs when unfolding. During the unfolding process, the various parts of the bed are locked in order and can be split step by step. After positioning the upper fence of the bed first, just continue to push the folding drive device down to fully open the bed; when the bed is folded , Pull the folding drive device so that the lower link can drive the transmission mechanism and then link with the pull rope to realize the folding operation of the guard bar, and realize the automatic operation of fully unlocking one place with force; during operation, the folding drive device controls the bed body Open and fold, it can be operated with one hand, which makes the operation safer, more convenient and stable, and the middle of the guard bar is provided with elasticity that can pull the rope in reverse to reset the transmission mechanism at the bottom of the bed leg when the guard bar needs to be folded. The positioning body makes the bed body fold more smoothly.

Description of the drawings

Figure 1 is a perspective view of an embodiment of the present invention applied to a folding bed;

Figure 2 is a perspective view of a base in Figure 1 with half of the shell removed;

3 is a schematic diagram of the structure of FIG. 2 after half of the swing block is cut away from the base where half of the shell is removed;

Figure 4 is a perspective view of Figure 2 after being folded;

Figure 5 is a perspective view of Figure 4 after continuing to fold to the completion of the folding;

Fig. 6 is a structural schematic diagram showing the positional relationship between the driving roller and the arc-shaped end in Fig. 4;

Fig. 7 is a schematic structural diagram showing the positional relationship between the driving roller and the arc-shaped end in Fig. 5;

Figure 8 is a top view of Figure 1 after removing the connecting structure of the legs and the upper part of the legs;

Fig. 9 is a top view of the second locking mechanism in Fig. 8;

Figure 10 is a cross-sectional view along line A-A in Figure 8;

Figure 11 is a cross-sectional view of the pulling part in Figure 10 after being pulled up to unlock;

Figure 12 is a cross-sectional view along line B-B in Figure 9;

13 is a cross-sectional view of the pulling part when the pulling part is pulled after pressing the unlocking lever in FIG. 12;

Figure 14 is a schematic structural diagram of the connecting rod in Figure 2 connected with the corresponding leg, base (partial), and folding drive device;

Figure 15 is a front projection view of Figure 14 with one set of connecting rods retained and the side of the set of connecting rods as the front;

Fig. 16 is a structural schematic diagram of the connecting rod and the folding driving device, the base, and the leg of the bed in Fig. 15 moving to different positions;

Fig. 17 is a perspective view of the middle part of a guard bar in Fig. 2 with half of the shell removed;

Fig. 18 is a perspective view showing the specific structure of the guard bar when the guard bar in Fig. 17 is taken out separately;

Figure 19 is a front projection view of Figure 18;

20 is a schematic diagram of the structure of the elastic positioning body unlocking the rotating part when the transmission mechanism in FIG. 19 relaxes the rope;

Figure 21 is an exploded view of the structure of Figure 18;

Fig. 22 is an exploded view of the structure of Fig. 11.

Preferred embodiment of the present invention

The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

As shown in Figures 1-22, the lower folding mechanism of the children’s play bed includes a base 2 connected to the bottom of each leg 1 and one end can be movably connected to the base 2 and the other end can be foldable and unfolded with the middle of the bottom of the bed. The folding drive device is movably connected to the connecting rod, the lower folding mechanism further includes a swing block 3 arranged in the inner cavity of the base that can pull the rope 4, and the swing block 3 is swingably arranged in the lower cavity of the base 2 through the swing shaft 37 In 23, the connecting rod movably connected to each base 2 is composed of an upper connecting rod 21 and a lower connecting rod 31 arranged up and down. The corresponding position is connected by rotation, the other end of the upper link 21 extends into the upper cavity 22 of the base 2 and is rotatably connected with the base 2 by the upper shaft pin 221, and the other end of the lower link 31 extends into the base The lower inner cavity 23 of the base 2 is rotationally connected with the base 2 by the lower shaft pin 231, and the end of the lower link that extends into the lower inner cavity 23 of the base 2 is linked with the swing block 3, and the lower axle pin 231 is set in the swing In the inner cavity of the base at the upper right position of the block 3, the swing block 3 is provided with a drive roller 34 that can contact with the end of the lower link and can push the swing block 3 to swing to the left, and a drive roller 34 that can be connected with the draw rope 4 The connecting shaft 36 and the swing shaft 37 are arranged at the lower position of the swing block 3 at the lower left of the lower shaft pin 231, and the connecting shaft 36 connected with the drawstring 4 is fixed on the left side of the swing shaft 37.

The swinging block 3 is an integral structure formed by symmetrically connecting two fan-shaped swinging pieces. The middle part between the two swinging pieces is fixed together by the swinging piece connecting column 35. The inner cavity of the swinging block 3 is composed of two swinging pieces. The cavity formed between. When the bed is folded, the drive roller 34 is located on the right side of the swing shaft 37, the drive roller 34 and the connecting shaft 36 are respectively located in the cavity of the swing block 3, and the end of the lower link in the inner cavity of the base extends into the swing block In the cavity of 3, the end of the lower link that extends into the cavity of the swing block 3 is an arc-shaped end 32. When the children's play bed is fully expanded and the other end of the lower link 31 moves down to the lowest end , The bottom end of the arc-shaped end 32 of the lower link 31 is supported together with the drive roller 34. When the children’s play bed is gradually folded and folded, the end surface of the arc-shaped end 32 of the lower link 31 moves away from the drive roller 34 The shaft center of the driving roller moves until the frame body 6 moves up to the highest end, and one side of the arc-shaped end 32 and the driving roller 34 are supported together. The transmission roller 34 is composed of a positioning shaft pin 33 pierced and connected on two swinging pieces and a transmission wheel 341 rotatably sleeved on the positioning shaft pin 33 in the cavity of the swing block. The side wall of the transmission wheel 341 can be connected to the arc The face ends 32 are in contact with each other; the two ends of the connecting shaft 36 are respectively inserted and fixed on two swinging pieces arranged in parallel on the left and right, the drawstring 4 is connected with the loop, and the loop is sleeved on the connecting shaft 36. The bottom of the base 2 is provided with a roller 25 that facilitates the movement of the bed leg 1 back and forth. The distance between the upper shaft pin 221 and the upper pivot pin 222 on the upper link 21 is smaller than the distance between the lower pivot pin 231 and the lower pivot pin 232 on the lower link 31. The bottom of the base 2 is provided with a roller 25 that facilitates the movement of the bed leg 1 back and forth. The bottom of the lower cavity 23 is provided with a third cavity 24, and the roller 25 is located in the third cavity 24.

The folding driving device includes a frame body 6 that can move up and down relative to the bed leg 1, a guide rod 61 that is vertically fixed in the middle of the frame body 6 and extends downward from the middle of the bottom surface of the frame body, and a guide rod 61 that can move up and down along the guide rod 61 The sliding seat 7, the other end of the upper connecting rod 21 and the lower connecting rod 31 movably connected to each bed leg 1 are respectively connected to the corresponding position of the frame body 6 through the upper rotating shaft pin 222 and the lower rotating shaft pin 232, and sliding The base 7 is movably connected to the corresponding lower connecting rod 31 through a transmission rod 38. The lower end of the transmission rod 38 is rotationally connected to the corresponding side surface of the sliding base 7 through a lower transmission pin 224, and the upper end of the transmission rod 38 is connected through an upper transmission shaft pin 223. Connected to the lower link 31 for rotation.

The frame body 6 is also provided with a locking mechanism that can maintain the unfolded state when the bed body is fully unfolded. The locking mechanism includes an unlocking rod 64 and a locking piece. The unlocking rod 64 can be moved up and down in the inner cavity of the guide rod 61, and the frame The center of the body 6 is provided with a vertical through hole 62 penetrating up and down. The guide rod 61 is inserted and fixed in the vertical through hole 62 of the frame body 6. The top surface of the guide rod 61 is flush with the top surface of the frame body, and the guide rod 61 The lower end of the frame body 6 extends downward from the bottom surface of the frame body 6, an unlocking structure of the unlocking rod 64 is provided on the top surface of the frame body 6, the locking piece is located in the inner cavity of the unlocking rod 64, when the folding driving device moves down to the lowest When the bed body is fully unfolded, the lock piece can be locked by supporting the bottom surface of the sliding seat 7 through the corresponding side surfaces of the unlocking rod 64 and the guide rod 61. When the bed body needs to be folded and unlocked, the lock piece is driven by the unlocking structure Retracting into the inner cavity of the unlocking lever 64 to disengage from the sliding seat 7, the sliding seat 7 can be moved downward to unlock.

The locking piece is located in the lower cavity of the unlocking lever 64. The locking piece is composed of at least two positioning pieces 63. The lower part of each positioning piece 63 is provided with a connecting hole for inserting the horizontal pin 66, and a positioning piece 63 above the connecting hole There is an oblique strip hole 631 on the upper part. The positioning piece 63 is folded together like a folding fan. The left and right ends of the shaft pin 66 are respectively fixed on the left and right corresponding side surfaces of the lower part of the guide rod 61, and a foldable pull that can move up and down in the oblique strip hole 631 to unfold and fold the positioning piece 63 is inserted in the oblique strip hole 631. The left and right ends of the folding shaft 65 are radially fixed on the left and right sides corresponding to the unlocking rod 64. The unlocking rod 64 is provided with a notch 641 that can extend out of the side of the unlocking rod when it is unfolded left and right. The left and right sides of the guide rod 61 at the corresponding position of 641 are also respectively provided with a through cavity 611 on the side of the guide rod after passing through the gap 641 when the positioning piece 63 is unfolded. 7 The bottom surfaces are supported together. The left and right sides of the unlocking lever 64 located in the upper part of the inner cavity of the unlocking lever are respectively provided with vertical waist-shaped holes 642. A fixed shaft pin 68 is inserted radially in the waist-shaped hole 642 to fix the shaft pin. The left end of 68 passes through the left side of the unlocking rod and is fixed together with the corresponding left side of the guide rod 61, and the right end of the fixed shaft pin 68 passes through the right side of the unlocking rod and is fixed together with the corresponding right side of the guide rod 61, which is located above the gap 641. The inner cavity of the unlocking lever is provided with a return spring 71, the bottom of the return spring 71 is supported by the support part in the inner cavity of the unlocking lever above the notch 641, and the upper end of the return spring 71 can be in contact with the fixed shaft pin 68 While supported together, the upper and lower hole distance L of the waist-shaped hole 642 is greater than the maximum distance K after the folding pull shaft 65 moves up and down to make the positioning piece 63 completely folded. The unlocking structure includes a pull ring 67 and a pull rope body. When the pull ring is selected, the two ends of the pull ring are connected with a rotatably pulling shaft connected to the top surface of the unlocking rod 64.

Alternatively, the top of the frame body 6 is connected with a pull portion 671 capable of pulling the frame body 6 upward, and the unlocking structure is that the unlocking rod 64 protrudes from the pressing and extending end of the vertical through hole 62 or the top surface of the unlocking rod is connected to the vertical through hole 62. Press the flush end with flush faces, the locking piece is located in the lower cavity of the unlocking rod 64, the locking piece is composed of at least two positioning pieces 63, and the upper part of each positioning piece 63 is provided with a connecting hole for inserting the horizontal shaft pin 66 The positioning piece 63 below the connecting hole is provided with a diagonal strip hole 632. The positioning piece 63 is folded together like a folding fan. The folding fan expands and folds left and right like the folding fan. The left and right ends of the horizontal axis pin 66 are respectively fixed on the corresponding left and right sides of the upper part of the guide rod 61. Unfold and fold the folding pull shaft 65 of the positioning piece 63. The left and right ends of the folding pull shaft 65 are radially fixed on the left and right sides corresponding to the unlocking rod 64. The unlocking rod 64 is provided with a positioning piece 63 that can be extended to unlock when unfolded left and right. The notch 641 on the side of the tie rod, and the left and right sides of the guide rod 61 corresponding to the notch 641 are respectively provided with a through cavity 611 on the side of the guide rod after the notch 641 is extended when the positioning piece 63 is unfolded. The buckling surface of the positioning piece 63 can be buckled together with the bottom surface of the sliding seat 7. The left and right sides of the unlocking lever located in the upper part of the inner cavity of the unlocking lever are respectively provided with vertical waist-shaped holes 642, and the horizontal axis pin 66 penetrates radially. In the waist-shaped hole 642, a return spring 71 is provided in the inner cavity of the guide rod below the through cavity 611. The support rod 69 in the inner cavity is supported. The upper and lower hole distance L of the waist-shaped hole 642 is greater than the maximum distance K after the folding pull shaft 65 moves up and down to fully fold the positioning piece 63. After pressing the top of the unlocking rod 64, the locking piece shrinks. Returning to the inner cavity of the unlocking lever 64 to disengage from the sliding seat 7, the pulling portion 671 that is pulled upward can move the sliding seat 7 downward to unlock.

The upper pole of the children’s play bed is surrounded by four guard bars 12. The guard bars 12 include a left rod body 12a and a right rod body 12b that can be movably connected to the top of the corresponding bed leg 1, and are located between the left rod body 12a and the right rod body 12b. The folding part of the left rod body 12a and the right rod body 12b can be folded. The folding part includes a housing 8, an elastic positioning body 9 located in the middle of the inner cavity of the housing 8, a left turning part located on the left side of the elastic positioning body 9 and an elastic positioning body 9 The right turning part on the right side, the right part of the left rod body 12a extends into the left cavity of the housing 8 and is rotatably connected with the housing 8, and the right end of the left rod body 12a is drivingly connected to the left turning part , The left turning part is connected with the drawstring 4 extending from the base of the left leg, the left part of the right rod body 12b extends into the inner cavity of the right part of the housing and is rotatably connected with the housing 8, the right rod body 12b The left end is connected with the right turning part, and the right turning part is connected with the pull cord 4 extending from the right leg base. When the bed is unfolded, the left rod body 12a and the right rod body 12b are unfolded through the folding part, The corresponding drawstring 4 simultaneously tightens the corresponding rotating parts, so that the corresponding supporting parts of the two rotating parts respectively support the corresponding positions on the elastic positioning body 9 so that the folding parts are locked together. When the bed body is folded, the corresponding The pull rope 4 is relaxed, the elastic positioning body 9 pushes the corresponding rotating part to rotate in the opposite direction to unlock the folding part, and the guard bar 12 is folded to drive the bed to fold.

Each rotating part includes a rotating block 81 and a positioning block 82. The middle part of the rotating block 81 is rotatably connected to the inner cavity of the corresponding housing through a rotating block shaft pin 812. One end of the rotating block 81 is movably connected with one end of the positioning block 82 for positioning. The other end of the block 82 is rotatably connected with the corresponding end of the left rod body 12a or the right rod body 12b, and the positioning block 82 is provided with a positioning protrusion 821 capable of contacting the elastic positioning body 9.

The positioning block 82 is composed of two positioning sheets with the same shape. The two positioning sheets are symmetrically arranged, and one end of the two positioning sheets sandwiches one end of the corresponding rotating block 81 and can be relatively movably connected by a rotating shaft 84 Together, the other ends of the two positioning pieces sandwich the ends of the corresponding left rod body 12a or the right rod body 12b and are connected to each other by rotation of the piece shaft pin 813, and one end of the corresponding drawstring 4 bypasses the corresponding rotation. The arc-shaped side wall of the block 81 is connected with the rotating shaft 84 together.

The elastic positioning body 9 includes an extrusion spring 91 and an extrusion rod 92 that can be in contact with the positioning protrusion 821. Two spring cavities 93 for placing the corresponding extrusion spring 91 are provided on the elastic positioning body 9 and placed in the spring cavity. One end of the compression spring 91 in 93 respectively touches the bottom surface of the corresponding spring cavity 93, and the other end of the compression spring 91 respectively touches the corresponding compression rod 92, and is in contact with the corresponding position of the compression spring 91. The side walls of the housing are respectively provided with limited waist-shaped through holes 83, and the squeezing rod 92 is inserted into the corresponding limiting waist-shaped through holes 83. When the guard rod 12 is unfolded, the squeezing rod 92 can interact with the positioning block 82. The positioning protrusions 821 are supported together. At this time, the three-point connection line of the corresponding group of the plate shaft pin 813, the rotating shaft 84, and the rotating block shaft pin 812 is located on a straight line from top to bottom. When the guard bar 12 is folded, The squeezing rod 92 pushes the positioning protrusion 821 to unlock the rotating shaft 84, and the positioning block 82 rotates to separate the squeezing rod 92 from the positioning protrusion 821. The side wall of the elastic positioning body 9 corresponding to the spring cavity 93 is provided with a side wall notch 94 capable of accommodating the corresponding extrusion rod 92. The arc-shaped side wall of the rotating block 81 is provided with hook-shaped protrusions 811 that can be inserted into the corresponding drawstring 4 at intervals. A limit slot 814 that can be inserted into the corresponding draw rope 4 is provided on the arc-shaped side surface of the rotating block 81, and the rope body corresponding to the draw rope 4 is located in the limit slot 814.

A left rope spring 41 is connected to the rope 4 under the left rod body 12a. One end of the left rope spring 41 is connected to the outer end of the rope 4 on the left rotating block, and the other end of the left rope spring 41 is pulled through The rope passes downward through the inner cavity of the left leg 1 and is connected to the transmission mechanism in the corresponding base 2. A right rope spring is connected to the rope 4 under the right rod body 12b, and one end of the right rope spring is connected to the right The outer end of the drawstring 4 on the rotating block is connected, and the other end of the right drawstring spring passes through the inner cavity of the right leg 1 through the drawstring and is connected to the corresponding transmission mechanism in the base 2. The lowest end B of the drawstring 4 connected with the folding part is lower than the point C where the drawstring 4 extends into the inner cavity of the corresponding bed leg. The inclined installation of the wire rope makes the pull rope 4 have an upward lifting effect on the folding part, so that the folding part located in the middle of the guard bar is easier to open, and the pull rope 4 has an upward force on the folding part, which has a lifting effect.

The bed leg 1 has a hollow structure, and the drawstring 4 extends into the bed leg 1 and extends from the opening of the upper side wall of the bed leg 1 to be connected to the middle of the guard bar 12. When the children's play bed is fully deployed, the included angle between the upper link 21 and the lower link 31 is 1.5-4°. The frame body 6 is provided with an auxiliary support rod 601 that can rotate relative to the frame body 6. The auxiliary support rod 601 is L-shaped. When the bed leg 1 is fully opened, the end of the L-shaped auxiliary support rod 601 touches the ground . The other end of the drawstring 4 passes through the inner cavity of the bed leg and passes through the inner cavity of the upper portion of the bed leg to be connected with the folding part. The transmission mechanism can be connected with the folding part of the middle part of the guard bar 12 on the top of the folding bed through the pull rope 4, and the arc-shaped end 32 is an elliptical end.

The connecting rod movably connected to each base 2 is composed of an upper connecting rod 21 and a lower connecting rod 31 arranged up and down. It is rotatably connected with the base 2. The other end of the upper link 21 is rotatably connected with the frame 6 in the folding drive device by the upper pivot pin 222, and one end of the lower link 31 extends into the lower cavity 23 of the base 2 The lower shaft pin 231 is rotatably connected with the base 2 and the end of the lower link that extends into the lower cavity 23 of the base 2 is linked with the transmission mechanism. The lower shaft pin 231 is located below the upper shaft pin 221 and the base 2 Rotational connection, the other end of the lower link 31 is rotatably connected with the frame body 6 by the lower rotation shaft pin 232, and the positioning point of the lower rotation shaft pin 232 on the frame body 6 is located diagonally above and to the right of the virtual point A The position of the height of the upper pivot pin 222, the virtual point A is the fourth point position of the parallelogram formed by connecting the three points of the upper pivot pin 221, the upper pivot pin 222, and the lower pivot pin 231. The angle a between the line connecting the positioning point of the lower pivot pin 232 and the virtual point A and the horizontal line is 45°.

Industrial applicability

Working principle: When the children's play bed is in the folded state, press the folding driving device to move downwards. The four-link mechanism composed of upper and lower links drives the legs of the bed to move outwards. The top of the leg expands quickly and the bottom of the leg expands slowly. The arc-shaped end 32 of the lower link pushes the drive roller 34 to make the swing block 3 swing in a counterclockwise direction, and drives the connecting shaft 36 to move downward in an arc. Pull the rope 4 downwards to drive the guard bar to lock. When the top is fully unfolded, the folding drive device continues to move downwards so that the connecting rod continues to push the bottom of the bed leg outwards until the bottom of the bed leg is fully unfolded to the normal state of use. When the folding driving device is pulled up to fold the bed, the above steps are restored.

The entire unfolding and folding process will be described in detail below in conjunction with the accompanying drawings:

The unfolding process of the present invention is shown in Figure 5→Figure 4→Figure 1.

Unfolding process: When the children's play bed is in the folded state, the folding driving device is at the highest position of the position it passes during the displacement process, the upper link 21 rotates upward to the vertical position, and the left and right rods of all guard bars rotate downward to make the guard The rod is folded, as shown in Figure 5. Press down the folding driving device, the folding driving device drives the upper link 21 and the lower link 31 to rotate. When the upper link 21 and the lower link 31 rotate, they drive the base 2 and the bed leg 1 to move outward (away from the center) while gradually moving Tilt to the outside, and synchronously drive the left and right rods to rotate (as shown in the H1 position in Figure 16); until the upper link 21 and the lower link 31 are approximately parallel, the bed leg 1 is at the maximum inclination angle (as shown in Figure 16).的 H2 position); continue to press down the folding drive device, when the upper link 21 and the lower link 31 rotate, the base 2 and the bed leg 1 move outward while gradually tilting to the inner side. At this time, the bed leg 1 pulls outward to correspond The connecting seat 5 on the top of the bed leg 1 keeps the connecting seat 5 away from each other, and the driving guard bar 12 expands to a nearly horizontal state, as shown in FIG. The lower link 31 rotates, and the arc-shaped end 32 of the lower link 31 pushes the drive roller 34 to swing the swing block 3 in a counterclockwise direction, and drives the connecting shaft 36 to move downward in an arc shape to pull the rope 4 downward to drive The corresponding guard bar 12 is expanded to a horizontal use state, and the folding part is locked; continue to press down the folding drive device until the children’s play bed is fully opened, and when the upper link 21 and the lower link 31 rotate, the base 2 and the bed leg 1 move outwards. At the same time, it gradually tilts to the inside to a vertical state, as shown in Figure 1. During this process, the connecting shaft 36 continues to move downward in an arc to pull the rope 4 downwards, so that the tension spring 41 is in a stressed state. , To ensure that the folding part is always in a constant state. The tension spring 41 plays a tensioning role. If the tension spring 41 is not used here, high requirements are placed on the manufacturing and processing of the drawstring 4, and it is difficult to guarantee the processing accuracy of the length of the drawstring 4 in general production technology. The length of the rope 4 between the connecting shaft 36 and the rotating shaft 84 is slightly longer, so that the rotating part of the folding part cannot be pulled in time, so that the folding part is not in the locked state; the length of the rope 4 between the connecting shaft 36 and the rotating shaft 84 is slightly shorter. 2 The transmission mechanism in the inner cavity that can pull the rope 4 causes the rope to be stressed, which will exceed the maximum load force of the rope and break. And the elastic force of the tension spring 41 is much greater than the elastic force of the compression spring 91 on the elastic positioning body 9. When the transmission mechanism in the inner cavity of the base 2 that can pull the rope 4 drives the folding part to lock, first Overcoming the gravity of the guard bar to expand the guard bar, and at the same time overcoming the elastic resistance of the compression spring 91, the pull rope 4 tightens the corresponding rotating part, and drives the rotating part to make the corresponding set of the plate shaft pin 813, the rotating shaft 84, and the rotating block shaft. The three-point line of the pin 812 is located on a straight line from top to bottom to lock the folded part. After that, the transmission mechanism continues to drive the pull rope 4 to make the tension spring 41 in a tension state. The locking piece protrudes from the corresponding side surfaces of the unlocking rod 64 and the guide rod 61 and is supported by the bottom surface of the sliding seat 7 to be locked. So far, the folding bed is in a fully opened and locked state.

The folding process of the present invention is shown in Figure 1→Figure 4→Figure 5.

Folding process: when the children’s play bed is in the unfolded state, as shown in Figure 1; the pull ring 67 on the folding driving device can be lifted up with only one hand, and the folding driving device is unlocked by the unlocking mechanism to allow the folding driving device to continue in Move in the upward direction; continue to lift the pull ring 67, the folding drive device drives the upper link 21 and the lower link 31 to rotate, when the upper link 21 and the lower link 31 rotate, the base 2 and the bed leg 1 move inwardly While gradually tilting to the outside; the end surface of the arc-shaped end 32 of the lower link 31 moves away from the transmission roller axis around the transmission roller 34, so that the pull rope 4 gradually loses its pulling force, and the elastic positioning body 9 in the folding part pushes the corresponding The rotating part rotates to unlock the folding part and fold the guard bar, as shown in Figure 4; continue to lift the pull ring 67, the guard bar drives the corresponding bed leg 1 to continue to move closer to the folding drive device, and the left and right rods of the guard bar 12 face Rotate down to the vertical position, so far the children's play bed is in a folded state, as shown in Figure 5.

By cleverly designing the connecting position of the upper link 21 and the lower link 31 to form a four-link mechanism, when the children's play bed is unfolded, the leg 1 can firstly tilt outward and then return to the vertical movement track. It is divided into two stages of unfolding process. When the bed body is just unfolded, the unfolding amplitude of the upper end of the bed leg is greater than the unfolding amplitude of the lower end of the bed leg. The body guard bar is convenient for single-person operation; while the bed body continues to unfold, the lower end of the bed leg gradually unfolds to catch up with the unfolding range of the upper end of the bed leg, and the bed leg returns to the vertical state to realize the complete deployment of the bed body It is a firm and durable unfolding bed that is not easy to fall down, suitable for children to jump and run.

Obviously, the present invention has a significant advantageous feature, that is, one-step operation, which pushes down or lowers the folding drive device to open the bed body, and pulls up or lifts the folding drive device to fold the bed body. When the bed is opened and folded, the movement of the folding drive device in any direction can simultaneously cause the movement of all other components and structures of the bed.

Claims

A lower folding mechanism for children's play bed, comprising a base (2) connected to the bottom of each bed leg (1), one end can be movably connected with the base (2), and the other end can be foldable and unfolded with the middle of the bed bottom The connecting rod movably connected to the folding driving device is characterized in that: the lower folding mechanism further comprises a swing block (3) arranged in the inner cavity of the base and capable of pulling the rope (4), and the swing block (3) swings The shaft (37) is swingably arranged in the lower cavity (23) of the base (2), and the connecting rod movably connected with each base (2) consists of an upper connecting rod (21) and a lower connecting rod ( 31) composition, one end of the upper link (21) and the lower link (31) are respectively connected to the corresponding position of the frame (6) in the folding driving device, and the other end of the upper link (21) It extends into the upper cavity (22) of the base (2) and is rotatably connected with the base (2) by the upper shaft pin (221). The other end of the lower link (31) extends into the base ( 2) The lower inner cavity (23) is connected by a lower shaft pin (231) and the base (2) in rotation, and extends into the lower connecting rod end and swing block in the lower inner cavity (23) of the base (2) (3) The lower shaft pin (231) is arranged in the inner cavity of the base at the upper right position of the swing block (3), and the swing block (3) is provided with the end of the lower connecting rod. The drive roller (34) that can push the swing block (3) to swing to the left and the connecting shaft (36) that can be connected with the pull rope (4), the swing shaft (37) is arranged on the lower shaft pin (231) In the lower left position of the swing block (3), the connecting shaft (36) connected with the drawstring (4) is fixed on the left side of the swing shaft (37).
The lower folding mechanism according to claim 1, characterized in that: the swing block (3) is an integral structure formed by symmetrically connecting two fan-shaped swinging pieces, and the middle part between the two swinging pieces is connected by the swinging piece The columns (35) are fixed together, and the inner cavity in the swing block (3) is a cavity formed between two swing pieces.
The lower folding mechanism according to claim 2, characterized in that: the transmission roller (34) and the connecting shaft (36) are respectively located in the cavity of the swing block (3) at the end of the lower link in the inner cavity of the base The end of the lower connecting rod that extends into the cavity of the swing block (3) is an arc-shaped end (32). When the children’s play cot is fully unfolded, the lower connecting rod When the other end of the rod (31) moves down to the lowest end, the bottom end of the arc-shaped end (32) of the lower link (31) is supported together with the driving roller (34). When the children’s play bed is gradually retracted, When folded, the arc-shaped end (32) of the lower link (31) moves around the drive roller (34) away from the axis of the drive roller until the frame (6) moves up to the highest end, the arc-shaped end ( One side of 32) is supported with the driving roller (34).
The lower folding mechanism according to claim 3, characterized in that: the transmission roller (34) is rotatably sleeved in the inner cavity of the swing block by a positioning shaft pin (33) inserted and connected to the two swing pieces The driving wheel (341) on the positioning shaft pin (33) is composed of the transmission wheel (341), the side wall of the transmission wheel (341) can be in contact with the arc end (32); the two ends of the connecting shaft (36) are respectively The utility model is inserted and fixed on two swing pieces arranged in parallel on the left and the right, the drawstring (4) is connected with the collar, and the collar is sleeved on the connecting shaft (36).
The lower folding mechanism according to any one of claims 1 to 4, characterized in that: the bottom of the base (2) is provided with a roller (25) that facilitates the movement of the bed leg (1) back and forth.
The lower folding mechanism according to any one of claims 1 to 4, characterized in that: the folding driving device comprises a frame body (6) that can move up and down relative to the bed leg (1), and is vertically fixed on the frame body ( 6) A guide rod (61) extending downwards from the middle of the bottom surface of the frame body and a sliding seat (7) that can move up and down along the guide rod (61) are movably connected to each bed leg (1) The other ends of the upper connecting rod (21) and the lower connecting rod (31) are respectively connected to the corresponding positions of the frame body (6) by the upper rotating shaft pin (222) and the lower rotating shaft pin (232), and the sliding seat ( 7) The transmission rod (38) is movably connected with the corresponding lower connecting rod (31), and the lower end of the transmission rod (38) is rotationally connected with the corresponding side surface of the sliding seat (7) through the lower transmission pin (224), The upper end of the transmission rod (38) is rotatably connected with the lower connecting rod (31) through the upper transmission shaft pin (223).
The lower folding mechanism according to claim 6, characterized in that: the frame body (6) is also provided with a locking mechanism that can maintain the unfolded state when the bed body is fully unfolded, and the locking mechanism includes an unlocking lever (64 ) And a locking piece, the unlocking rod (64) can be moved up and down in the inner cavity of the guide rod (61), the center of the frame (6) is provided with a vertical through hole (62) penetrating up and down, so The guide rod (61) is inserted and fixed in the vertical through hole (62) of the frame (6), the top surface of the guide rod (61) is flush with the top surface of the frame, and the guide rod (61) The lower end extends downward from the bottom surface of the frame body (6), an unlocking structure of the unlocking rod (64) is provided on the top surface of the frame body (6), and the locking piece is located in the inner cavity of the unlocking rod (64) When the folding driving device is moved down to the lowest position to fully unfold the bed, the locking piece can extend through the corresponding side surfaces of the unlocking rod (64) and the guide rod (61) to interact with the sliding seat (7). ) The bottom surface is supported and locked. When the bed needs to be folded and unlocked, the unlocking structure drives the locking piece to retract into the inner cavity of the unlocking lever (64) to disengage from the sliding seat (7), enabling the sliding seat (7) to move toward Move down to unlock.
The lower folding mechanism according to claim 7, characterized in that: the locking piece is located in the lower cavity of the unlocking rod (64), and the locking piece is composed of at least two positioning pieces (63), each positioning piece (63) The lower part of the) is provided with a connecting hole for inserting the horizontal pin (66), and an oblique strip hole (631) is provided on the positioning piece (63) above the connecting hole, and the positioning piece (63) is folded like a folding fan Together, the lower part of the positioning piece is inserted through the connecting hole through the horizontal axis pin (66) so that the positioning piece (63) can be unfolded and folded left and right like a folding fan. The left and right ends of the horizontal axis pin (66) are respectively fixed On the left and right corresponding sides of the lower part of the guide rod (61), a folding pull shaft that can move up and down in the oblique strip hole (631) to unfold and fold the positioning piece (63) is inserted in the oblique strip hole (631) (65), the left and right ends of the folding pull shaft (65) are radially fixed on the left and right sides corresponding to the unlocking pull rod (64), and the unlocking pull rod (64) is provided with a positioning piece (63) that expands left and right The notch (641) on the side of the unlocking rod can be extended at the same time, and the left and right sides of the guide rod (61) corresponding to the notch (641) are respectively provided with positioning pieces (63) through the notch (641) when unfolded and then extended The through cavity (611) on the side of the guide rod, the top surface of the positioning piece (63) protruding from the through cavity (611) can be supported together with the bottom surface of the sliding seat (7), and the unlocking rod (64) is located in the upper part of the inner cavity of the middle of the unlocking rod Vertical waist-shaped holes (642) are respectively opened on the left and right sides. A fixed shaft pin (68) is inserted radially in the waist-shaped hole (642), and the left end of the fixed shaft pin (68) passes through the left end of the unlocking lever. The side surface and the corresponding left side of the guide rod (61) are fixed together, and the right end of the fixed shaft pin (68) passes through the right side of the unlocking rod and is fixed together with the corresponding right side of the guide rod (61), which is located in the gap (641). ) Is provided with a return spring (71) in the inner cavity of the upper unlocking rod, and the bottom of the return spring (71) is supported by the support part in the inner cavity of the unlocking rod above the notch (641), and the return spring (71) The upper end of the spring (71) can be in contact with the fixed shaft pin (68) and be supported together. The upper and lower hole distance (L) of the waist-shaped hole (642) is greater than the vertical movement of the folding pull shaft (65) for positioning The maximum distance (K) after the sheet (63) is fully folded.
The lower folding mechanism according to claim 8, characterized in that: the unlocking structure comprises a pull ring (67) and a rope body. When the pull ring is selected, both ends of the pull ring are connected to the unlocking rod (64). Rotatable pulling shafts on the top surface are connected together.
The lower folding mechanism according to claim 7, characterized in that: the top of the frame (6) is connected with a pull portion (671) capable of pulling the frame (6) upward, and the unlocking structure is an unlocking rod extending The pressing and extending end of the vertical through hole (62) or the pressing and flushing end where the top surface of the unlocking rod is flush with the top surface of the vertical through hole (62), the locking piece is located in the lower cavity of the unlocking rod, and the locking piece It is composed of at least two positioning pieces (63). The upper part of each positioning piece (63) is provided with a connecting hole for inserting the horizontal pin (66), and the positioning piece (63) below the connecting hole is provided with a diagonal strip Hole (632), the positioning piece (63) is folded together like a folding fan, the upper part of the positioning piece is inserted together through the connecting hole through the horizontal axis pin (66) so that the positioning piece (63) can be unfolded left and right like a folding fan With folding, the left and right ends of the horizontal shaft pin (66) are respectively fixed on the left and right corresponding sides of the upper part of the guide rod (61), and the oblique strip hole (632) is pierced with an oblique strip hole (632). ) Moves up and down to unfold and fold the folding pull shaft (65) of the positioning piece (63). The left and right ends of the folding pull shaft (65) are radially fixed on the corresponding left and right sides of the unlocking rod (64). The unlocking rod (64) is provided with a notch (641) that can extend out the side of the unlocking rod when the positioning piece (63) is expanded left and right, and the left and right sides of the guide rod (61) corresponding to the notch (641) are also respectively provided When the positioning piece (63) is unfolded, it passes through the gap (641) and then extends out of the through cavity (611) on the side of the guide rod. Snap together, the left and right sides of the unlocking lever located in the upper part of the inner cavity of the unlocking lever are respectively provided with vertical waist-shaped holes (642), and the horizontal shaft pin (66) is radially inserted through the waist-shaped holes (642) In the inner cavity of the guide rod located below the through cavity (611), a return spring (71) is arranged, and the upper end of the return spring (71) is in contact with the unlocking rod (64), and the return spring The lower end of (71) is supported by the support rod (69) located in the inner cavity of the guide rod, and the upper and lower hole distance (L) of the waist-shaped hole (642) is greater than the vertical movement of the folding pull shaft (65) to make the positioning piece (63) The maximum distance after fully folded (K), after pressing the top of the unlocking lever (64), the locking piece is retracted into the inner cavity of the unlocking lever (64) and disengaged from the sliding seat (7), and the pulling part is pulled upwards (671) The sliding seat (7) can be moved down to unlock.