Rotary telescopic positioning connection structure

Abstract

The utility model discloses a rotary telescopic positioning connection structure convenient for telescopic storage of a ladder, which comprises a positioning pin with a positioning position for being inserted into a positioning hole and an unlocking position for being moved out of the positioning hole; the positioning base is provided with a positioning bulge; the lock catch knob is rotatably arranged on the positioning base; the lock catch knob is connected with the positioning pin; the lock catch knob is provided with a first positioning caulking groove and a second positioning caulking groove which are used for embedding the positioning bulge; the depth, which can be embedded by the positioning bulge, of the first positioning caulking groove is greater than the depth, which can be embedded by the second positioning caulking groove; the lock catch rotary knob is provided with a deep positioning position and a shallow positioning position which are switched through rotation, and drives the positioning pin to move in the axial direction in the rotation switching process. When the lock catch knob is located at the deep positioning position, the positioning bulge of the positioning base is embedded into the first positioning caulking groove; when the lock catch knob is located at the shallow positioning position, the positioning protrusion of the positioning base is embedded into the second positioning caulking groove.

Description

Technical Field

[0001] The present application relates to the field of connection structures, and particularly to a rotary telescopic positioning connection structure. Background Art

[0002] Ladders have different meanings, such as in steps, stairs, folding ladders of different sizes, ladders, extension ladders, etc. Ladders are used to reach many different heights, including changing light bulbs, reaching into tall cabinets, climbing onto the roof of a house, climbing onto a truck or a recreational vehicle, and so on.

[0003] Among them, the commonly seen ladders for load trucks on the market are generally welded by steel frames, occupying a large amount of space and not being convenient for folding and storage. Even when using common shrinkage structures, they usually adopt a folding structure. The operator needs to manually fold the ladder at the lower part to the upper part for fixation, which is time-consuming and laborious, and the operation is very inconvenient. There is also a certain operation risk in the case of a large weight. Summary of the Invention

[0004] In view of the above deficiencies, an object of the present application is to provide a rotary telescopic positioning connection structure to facilitate the telescoping of a ladder.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] A rotary telescopic positioning connection structure, the rotary telescopic positioning connection structure is applied to a telescopic ladder structure having an inner ladder and an outer ladder. A plurality of positioning holes are provided at different positions on the left and right side walls of the inner ladder in its length direction; the rotary telescopic positioning connection structure can be fixedly installed on the outer ladder and operably inserted into the positioning holes to operably position or slidably connect the outer ladder outside the inner ladder, so that the outer ladder is positioned and connected at different positions in the extending direction of the inner ladder;

[0007] Among them, the rotary telescopic positioning connection structure includes:

[0008] A positioning pin that can move axially, having a positioning position for inserting into the positioning hole and an unlocking position for moving out of the positioning hole;

[0009] A positioning base that can be fixedly installed on the outer ladder, which is provided with a positioning protrusion and an elastic member that applies an elastic force to the positioning pin to move towards the positioning position;

[0010] A latch knob rotatably arranged on the positioning base; the latch knob is connected to the positioning pin; the latch knob is provided with a first positioning groove and a second positioning groove for the positioning protrusion to be embedded; the depth that the first positioning groove can be embedded by the positioning protrusion is greater than the depth that the second positioning groove can be embedded; the latch knob has a deep positioning position and a shallow positioning position switched by rotation, and drives the positioning pin to move axially during the rotation switching process; when the latch knob is in the deep positioning position, the positioning protrusion of the positioning base is embedded in the first positioning groove; when the latch knob is in the shallow positioning position, the positioning protrusion of the positioning base is embedded in the second positioning groove.

[0011] As a preferred aspect, the depth difference between the positioning protrusion embedded in the first positioning groove and the second positioning groove is equal to the axial movement amount of the positioning pin at the positioning position and the unlocking position.

[0012] As a preferred aspect, the first positioning groove and the second positioning groove are arranged at the edge of the latch knob; the edge track of the latch knob smoothly extends from the bottom of the first positioning groove to the notch of the second positioning groove.

[0013] As a preferred aspect, a lifting transition curve is provided between the bottom of the first positioning groove and the notch of the second positioning groove, and the radius of curvature of the lifting transition curve gradually decreases from the first positioning groove to the second positioning groove.

[0014] As a preferred aspect, the width of the first positioning groove gradually increases in the direction from its bottom to its notch; the cross-sectional shape of the positioning protrusion matches the shape of the first positioning groove.

[0015] As a preferred aspect, a shaft tube for the positioning pin to pass through is further provided on the positioning base; a top abutment step is provided at one end of the shaft tube close to the latch knob; a limit step is provided at the insertion end of the positioning pin; the elastic member includes a spring sleeved outside the positioning pin in the shaft tube; the spring is compressed between the top abutment step and the limit step.

[0016] As a preferred aspect, the rotation angle for the latch knob to switch between the deep positioning position and the shallow positioning position is 90 degrees.

[0017] As a preferred aspect, first positioning grooves are respectively provided at both ends of the latch knob along its length direction, and two opposite knob side plates are provided between the two first positioning grooves; the second positioning groove is located at the middle position of the edge of the knob side plate; a knob part for receiving force application is further provided at the top end of the latch knob on the knob side plate.

[0018] As a preferred aspect, the central position of the knob part is fixedly connected to the positioning pin and the locking knob by a connecting pin rod passing through the connecting end of the positioning pin.

[0019] As a preferred aspect, the locking knob has an embedded cavity between the two knob side plates; the locking knob is further provided with a slot inside the embedded cavity; when the locking knob is in the deep positioning position, one end of the shaft tube is inserted into the slot.

[0020] The present application has the following beneficial effects:

[0021] The rotary telescopic positioning connection structure provided by the present application can be applied to the sliding positioning connection of the inner ladder and the outer ladder to form a telescopic ladder structure. This rotary telescopic positioning connection structure can position the outer ladder step by step along the inner ladder, facilitating the user to form a ladder of the desired length as expected. And when storing, it is very convenient to shorten the ladder to the shortest by rotating the rotary telescopic positioning connection structure.

[0022] Moreover, through the design of the first positioning groove and the second positioning groove with different depths in cooperation with the positioning protrusion, the rotary telescopic positioning connection structure fits and embeds the grooves with different depths and the positioning protrusion by rotating the knob, thereby driving the axial telescopic movement of the positioning pin to realize the limitation or release of the outer ladder. And the design of the positioning grooves with different depths can stably limit the outer ladder during positioning, while when releasing it, the locking knob can be weakly positioned at the shallow positioning position, and in this state, the locking knob can be rotated with a little force, which is very convenient.

[0023] Referring to the following description and the drawings, specific embodiments of the present invention are disclosed in detail, indicating the ways in which the principles of the present invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0024] Features described and / or illustrated for one embodiment can be used in the same or similar way in one or more other embodiments, combined with the features in other embodiments, or replace the features in other embodiments.

[0025] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, whole things, steps or components, but does not exclude the presence or addition of one or more other features, whole things, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 is a schematic three-dimensional structure diagram of a rotary telescopic positioning connection structure in an embodiment of the present application;

[0028] Figure 2 is Figure 1 another view of

[0029] Figure 3 is Figure 1 a schematic diagram of the state in the shallow positioning position;

[0030] Figure 4 is Figure 1 an exploded view of

[0031] Figure 5 is Figure 1 a sectional view in the state of the shallow positioning position;

[0032] Figure 6 is Figure 1 a sectional view in the state of the deep positioning position;

[0033] Figure 7 is applied with Figure 1 a three-dimensional structure diagram of a truck ladder;

[0034] Figure 8 is Figure 7 a schematic diagram of the installation position of the rotary telescopic positioning connection structure of

[0035] Figure 9 is Figure 7 a schematic diagram of the positioning hole of

[0036] Explanation of reference numerals:

[0037] 10. Platform part; 20. Step ladder part; 21. Inner ladder; 22. Outer ladder; 24. Handrail; 30. Locking plate; 40. Rotary telescopic positioning connection structure;

[0038] 210. Inner ladder rod; 211. First step; 215. Positioning hole; 217. Right side wall of the inner ladder rod;

[0039] 221. Outer ladder rod; 225. Second step; 227. Right side wall of the outer ladder rod;

[0040] 41. Positioning base; 411. Positioning protrusion; 412. Shaft tube; 413. Upper end of the shaft tube; 418. Abutting step; 419. Limiting step;

[0041] 42. Locking knob; 420. Embedded cavity; 421. First positioning groove; 422. Second positioning groove; 423. Lifting transition curve; 429. Connecting pin rod;

[0042] 45. Insertion end; 46. Positioning pin; 47. Connecting screw; 49. Spring. Specific embodiments

[0043] In order to enable those skilled in the art of the present technology to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0044] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be another intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be another intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation manner.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0046] As Figures 1 to 9 shown, an embodiment of the present application provides a rotary telescopic positioning connection structure 40, and the rotary telescopic positioning connection structure 40 is applied to a telescopic ladder structure having an inner ladder 21 and an outer ladder 22. The left and right side walls (right side wall 217 of the inner ladder rod) of the inner ladder 21 are provided with a plurality of positioning holes 215 at different positions in its length direction; the rotary telescopic positioning connection structure 40 can be fixedly installed on the outer ladder 22 and operably inserted into the positioning holes 215 to operably position or slidably connect the outer ladder 22 outside the inner ladder 21, so that the outer ladder 22 is positioned and connected at different positions in the extending direction of the inner ladder 21.

[0047] The rotary telescopic positioning connection structure 40 is applied to extend and shorten a stepped structure or a rod structure such as a ladder. In this embodiment, the rotary telescopic positioning connection structure 40 is applied to a ladder such as a truck ladder to extend and shorten the tread part 20 of the ladder.

[0048] The following will describe this embodiment in detail in combination with the overall structure of the truck ladder to better understand the present invention.

[0049] As Figure 7 shown, the truck ladder includes a platform part 10 and a tread part 20. The tread part 20 is a telescopic ladder structure. One end of the platform part 10 is hinged to one end of the tread part. The platform part 10 is horizontally arranged, and the tread part 20 has a flat position horizontally placed with the platform part 10 and a use position at a predetermined angle with the platform part 10. When the tread part is in the use position, it is vertically placed below the platform part 10 as a whole and forms an angle of approximately 100 degrees - 150 degrees with the platform part 10.

[0050] The platform part 10 includes parallel platform frame rods and a tabletop located between the platform frame rods. The platform part 10 is generally horizontally fixed or rotatably positioned on the vehicle body. Of course, it can also be an overall mobile ladder, placed at the target position by the user and horizontally placed and positioned.

[0051] The tread part is rotatably connected to one end of the platform part 10 and can be flipped up and down at one end of the platform part 10 to switch between the flat position and the use position. Among them, the tread part includes an inner ladder 21 and an outer ladder 22; a handrail 24 is provided on the outer ladder 22. The outer ladder 22 is operably slid or positioned and connected outside the inner ladder 21 to extend or shorten the tread part. The outer ladder 22 and the inner ladder 21 are slidably connected through the rotary telescopic positioning connection structure 40. The upper end of the inner ladder 21 is rotatably connected to one end of the platform part 10. Specifically, the upper end of the inner ladder 21 is locked and positioned through a locking plate 30. When the tread part 20 is in the use position, the positions of the tread part and the platform part 10 are fixed to each other through the locking plate 30 to form a stable structure for use, facilitating the user to use.

[0052] A plurality of positioning holes 215 are provided at different positions on the left and right side walls of the inner ladder 21 in its length direction; the rotary telescopic positioning connection structure 40 can be fixedly installed on the outer ladder 22 and operably inserted into the positioning holes 215 to operably position or slidably connect the outer ladder 22 outside the inner ladder 21, so that the outer ladder 22 is positioned and connected at different positions in the extending direction of the inner ladder 21.

[0053] It should be noted that the "up, down, left, and right" of the present invention are defined with reference to the orientation of the ladder in the use state.

[0054] In this embodiment, the inner ladder 21 has parallel inner ladder rods 210 and a plurality of first treads 211 connecting the two inner ladder rods 210; the plurality of first treads 211 are parallel to each other and are perpendicularly connected between the two inner ladder rods 210. The outer ladder 22 has parallel outer ladder rods 221 and a plurality of second treads 225 connecting the two outer ladder rods 221. The plurality of second treads 225 are parallel to each other and are perpendicularly connected to one side of the two outer ladder rods 221. Among them, the first treads 211 and the second treads 225 are parallel. The distance between two adjacent first treads 211 is equal to the distance between two adjacent second treads 225. The tread can be a rod or a plate. In this embodiment, the first tread 211 is a pedal structure and the second tread 225 is a tread rod structure.

[0055] The two outer ladder rods 221 are provided with sliding grooves opposite to each other on the left and right. The two inner ladder rods 210 are respectively embedded in the sliding grooves of the two outer ladder rods 221. The outer ladder rods 221 rely on the sliding grooves and are sleeved outside the inner ladder rods 210, and slide along the inner ladder rods 210 under the guidance of the inner ladder rods 210. The second treads 225 are fixedly connected to the outside of the outer ladder rods 221. When the first treads 211 and the second treads 225 are aligned, the second treads 225 are located outside the first treads 211. Of course, the second treads 225 can also be slightly lower than the first treads 211 to facilitate the user to step on and climb.

[0056] The rotary telescopic positioning connection structure 40 is fixedly connected to the outer ladder 22. Specifically, the two rotary telescopic positioning connection structures 40 are respectively located on the left and right side walls (one left side wall and one right side wall 227) of the two outer ladder rods 221 of the outer ladder 22.

[0057] The rotary telescopic positioning connection structure 40 includes a positioning pin 46 that can be telescoped along the length direction of the second tread 225, a positioning base 41, and a locking knob 42 that is rotatably arranged on the positioning base 41. Specifically, the rotary telescopic positioning connection structure 40 includes: a positioning pin 46 that can move axially, having a positioning position inserted into the positioning hole 215 and an unlocking position removed from the positioning hole 215; a positioning base 41 that can be fixedly installed on the outer ladder 22, which is provided with a positioning protrusion 411 and an elastic member that applies an elastic force to the positioning pin 46 to move it toward the positioning position; and a locking knob 42 that is rotatably arranged on the positioning base 41.

[0058] The axial direction of the positioning pin 46 is the length direction of the second tread 225 and is perpendicular to the inner and outer ladder rods 221. One end of the positioning pin 46 is a connection end connected to the locking knob 42, and the other end is an insertion end 45. The positioning pin 46 can rotate following the locking knob 42. The locking knob 42 drives the positioning pin 46 to rotate around the rotation axis, and this rotation axis is parallel to the length direction of the second tread 225.

[0059] The latch knob 42 is connected to the positioning pin 46; the latch knob 42 is provided with a first positioning groove 421 and a second positioning groove 422 for the positioning protrusion 411 to be embedded; the depth that the first positioning groove 421 can be embedded by the positioning protrusion 411 is greater than the depth that the second positioning groove 422 can be embedded. The latch knob 42 has a deep positioning position and a shallow positioning position that are switched by rotation, and drives the positioning pin 46 to move axially during the rotation and switching process. When the latch knob 42 is in the deep positioning position, the positioning protrusion 411 of the positioning base 41 is embedded in the first positioning groove 421; when the latch knob 42 is in the shallow positioning position, the positioning protrusion 411 of the positioning base 41 is embedded in the second positioning groove 422.

[0060] The depth difference between the embedding depths of the positioning protrusion 411 in the first positioning groove 421 and the second positioning groove 422 is equal to the axial movement amount of the positioning pin 46 between the positioning position and the unlocking position. The first positioning groove 421 and the second positioning groove 422 are provided at the edge of the latch knob 42; the edge track of the latch knob 42 smoothly extends from the bottom of the first positioning groove 421 to the notch of the second positioning groove 422. The groove width (the distance between the two knob side plates) of the first positioning groove 421 gradually increases along the direction from its bottom to its notch.

[0061] In this embodiment, the positioning base 41 is fixedly connected to the outer ladder rod 221, as Figure 4 shown, the positioning base 41 is fixedly connected to the left side wall or the right side wall 227 of the outer ladder rod 221 by a connecting screw 47. Through holes for the positioning pin 46 to pass through are also provided on the side walls (one left side wall and one right side wall 227) of the two outer ladder rods 221.

[0062] The positioning base 41 has a positioning protrusion 411 protruding from the left and right side walls of the outer ladder rod 221, and the positioning base 41 extends along the length direction of the outer ladder rod 221. The cross-sectional shape of the positioning protrusion 411 is basically matched with the cross-sectional shape of the first positioning groove 421. The cross-sectional shape of the second positioning groove 422 is basically matched with the cross-sectional shape of the top part of the positioning protrusion 411. The edge track of the latch knob 42 smoothly extends from the bottom of the first positioning groove 421 to the notch of the second positioning groove 422. There is a lifting transition curve 423 between the bottom of the first positioning groove 421 and the notch of the second positioning groove 422, and the radius of curvature of this lifting transition curve 423 gradually decreases from the first positioning groove 421 to the second positioning groove 422.

[0063] The latch knob 42 has opposite knob side plates, and an embedded cavity 420 is formed between the two knob side plates. First positioning grooves 421 are respectively formed at both ends of the latch knob 42 in the embedded cavity 420. Second positioning grooves 422 are provided on the knob side plates. Among them, the groove depth of the first positioning groove 421 is greater than that of the second positioning groove 422. The difference between the groove depth of the first positioning groove 421 and the groove depth of the second positioning groove 422 is approximately the telescopic distance of the positioning pin 46.

[0064] Continuing the above description, the latch knob 42 has a deep positioning position and a shallow positioning position that can be switched by rotation. When the latch knob 42 is in the deep positioning position, the positioning protrusion 411 of the positioning base 41 is embedded in the first positioning groove 421. When the latch knob 42 is in the shallow positioning position, the top end of the positioning protrusion 411 of the positioning base 41 is embedded in the second positioning groove 422. The rotation angle of the latch knob 42 when switching between the deep positioning position and the shallow positioning position is 90 degrees. When the latch knob 42 is in the shallow positioning position, the force required to disengage from this position is small, and the user only needs to apply appropriate force to rotate the latch knob 42, which is convenient for the user to operate.

[0065] A plurality of positioning holes 215 are provided along the length direction of the inner ladder rod 210. The positioning holes 215 can be provided by the first tread 211, and the positioning holes 215 at different heights correspond to the first treads 211 at different heights. The first tread 211 has a tread support rod, and the rod end of the tread support rod passes through the inner ladder rod 210 and provides the positioning holes 215. The insertion end 45 of the positioning pin 46 can be inserted into the positioning holes 215, and the outer ladder 22 is positioned at the current position by the first tread 211 (inner ladder rod 210).

[0066] Of course, the positioning holes 215 can also be staggered from the first tread 211 and only opened on the inner ladder rod 210. At this time, the positioning pin 46 is inserted into the positioning holes 215, and the outer ladder 22 is supported and limited by the inner ladder rod 210. The present application is not limited to the illustrated embodiments.

[0067] The positioning base 41 is provided with a through hole for the positioning pin 46 to pass through. A shaft tube 412 is provided on the positioning base 41. The through hole is located inside the shaft tube 412. The shaft tube 412 and the positioning base 41 are of an integral structure. The outer end of the shaft tube 412 is provided with an abutting step 418. The elastic member includes a spring 49 located inside the through hole; the spring 49 is sleeved outside the positioning pin 46. A limiting step 419 is provided at the insertion end 45 of the positioning pin 46. The spring 49 is compressed between the abutting step 418 and the limiting step 419. One end of the spring 49 abuts against the abutting step 418, and the other end abuts against the limiting step 419, thereby applying an elastic force in the insertion direction to the positioning pin 46. Relying on the elastic force of the elastic member, the lock knob 42 can be closely attached to the positioning base 41 and stably limited at the deep positioning position and the shallow positioning position, and it is not easy to have an unexpected rotational dislocation. Furthermore, the positioning pin 46 can have a stable positioning position, which is convenient for positioning the inner ladder 21 and the outer ladder 22 at the desired telescopic position.

[0068] The upper end of the lock knob 42 is a knob part, which is located at the top of the two knob side plates. At the central position of the knob part, the connecting end of the positioning pin 46 is passed through by a connecting pin rod 429 to fixedly connect the positioning pin 46 and the lock knob 42. A slot is also provided inside the lock knob 42. The slot is located at the middle position of the embedded cavity 420 for the upper end 413 (outer end, the end close to the lock knob 42) of the shaft tube to be inserted and at the same time facilitate the positioning protrusion 411 to be embedded into the first positioning groove 421 to a sufficient depth, so as to firmly position the relative positions of the inner ladder 21 and the outer ladder 22.

[0069] A plurality of left - right aligned positioning holes 215 are respectively provided on the left and right side walls of the two inner ladder rods 210, and the positioning holes 215 are located on the left and right sides of the first step 211. There are corresponding positioning holes 215 on both sides of each first step 211. Furthermore, the outer ladder 22 can be gradually positioned and connected to the inner ladder 21 through the rotary telescopic positioning connection structure 40. The rotary telescopic positioning connection structure 40 is fixedly connected to the upper end of the outer ladder 22. The two left - right rotary telescopic positioning connection structures 40 are rotated and operated together so that they are simultaneously located at the deep positioning position or the shallow positioning position, realizing the positioning or sliding of the outer ladder 22 on the inner ladder 21.

[0070] During use, when the lock knob 42 rotates 90 degrees to enter the shallow positioning position (such as Figure 3 、 Figure 5 the state positions shown), after the outer frame is unlocked and limited, the outer ladder 22 can slide up and down along the inner ladder 21 to a suitable position, and then rotate 90 degrees again to re - enter the deep positioning position (such as Figure 1 、 Figure 6 the state positions shown). After the outer ladder 22 is locked, the structure of the ladder part 20 is fixed and can be used.

[0071] It should be understood that the above description is for illustrative purposes and not for limitation. Upon reading the above description, many embodiments and many applications other than the provided examples will be apparent to those skilled in the art. Therefore, the scope of this teaching should not be determined with reference to the above description, but rather should be determined with reference to the appended claims and the full scope of equivalents to which those claims are entitled. For the sake of completeness, all articles and references, including patent applications and published disclosures, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the foregoing claims is not intended to abandon such subject matter, nor should it be considered that the inventor did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A rotary telescopic positioning connection structure, characterized in that: The rotary telescopic positioning connection structure is applied to a telescopic ladder structure having an inner ladder and an outer ladder, and the left and right side walls of the inner ladder are provided with a plurality of positioning holes at different positions in the length direction thereof; the rotary telescopic positioning connection structure can be fixedly mounted on the outer ladder and operably inserted into the positioning holes, so that the outer ladder can be operably positioned or slidably connected to the outside of the inner ladder, so that the outer ladder is positioned and connected to different positions in the extension direction of the inner ladder; Wherein, the rotary telescopic positioning connection structure comprises: A positioning pin movable in the axial direction, having a positioning position for inserting into the positioning hole and an unlocking position for moving out of the positioning hole; A positioning base that can be fixedly mounted on the outer ladder, and is provided with a positioning protrusion and an elastic member that applies an elastic force to the positioning pin to move toward the positioning position; A locking knob rotatably arranged on the positioning base; the locking knob is connected to the positioning pin; the locking knob is provided with a first positioning groove and a second positioning groove for the positioning protrusion to be embedded; the depth to which the first positioning groove can be embedded by the positioning protrusion is greater than the depth to which the second positioning groove can be embedded; the locking knob has a deep positioning position and a shallow positioning position switched by rotation, and drives the positioning pin to move axially during the rotation switching process; when the locking knob is in the deep positioning position, the positioning protrusion of the positioning base is embedded in the first positioning groove; when the locking knob is in the shallow positioning position, the positioning protrusion of the positioning base is embedded in the second positioning groove.

2. The rotary telescopic positioning connection structure according to claim 1, characterized in that: The difference in depth between the first positioning groove and the second positioning groove into which the positioning protrusion is embedded is equal to the axial movement of the positioning pin between the positioning position and the unlocking position.

3. The rotary telescopic positioning connection structure according to claim 1, characterized in that: The first positioning groove and the second positioning groove are arranged at the edge of the locking knob; the edge track of the locking knob smoothly extends from the groove bottom of the first positioning groove to the groove opening of the second positioning groove.

4. The rotary telescopic positioning connection structure according to claim 3, characterized in that: A lifting transition curve is formed between the groove bottom of the first positioning embedding groove and the groove opening of the second positioning embedding groove, and the curvature radius of the lifting transition curve gradually decreases from the first positioning embedding groove to the second positioning embedding groove.

5. The rotary telescopic positioning connection structure according to claim 1, characterized in that: The width of the first positioning groove gradually increases from the groove bottom to the groove opening; the cross-sectional shape of the positioning protrusion matches the shape of the first positioning groove.

6. The rotary telescopic positioning connection structure according to any one of claims 1 to 5, characterized in that: The positioning base is also provided with an axis tube for the positioning pin to pass through; the end of the axis tube close to the locking knob is provided with a push step; the insertion end of the positioning pin is provided with a limit step; the elastic member includes a spring sleeved inside the axis tube and outside the positioning pin; the spring is compressed between the push step and the limit step.

7. The rotary telescopic positioning connection structure according to claim 1, characterized in that: The rotation angle of the locking knob for switching between the deep positioning position and the shallow positioning position is 90 degrees.

8. The rotary telescopic positioning connection structure according to claim 6, characterized in that: The locking knob is provided with a first positioning groove at both ends along its length direction and two opposite knob side plates are provided between the two first positioning grooves; the second positioning groove is located at the center of the edge of the knob side plate; the locking knob is also provided with a knob part for receiving force at the top end of the knob side plate.

9. The rotary telescopic positioning connection structure according to claim 8, characterized in that: The center position of the knob portion passes through the connecting end of the positioning pin via a connecting pin rod, thereby fixing the positioning pin and the locking knob.

10. The rotary telescopic positioning connection structure according to claim 9, characterized in that: The locking knob has an embedded cavity between the two knob side plates; the locking knob is also provided with a slot inside the embedded cavity; when the locking knob is in the deep positioning position, one end of the shaft tube is inserted into the slot.

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