A quick-change joint

Abstract

The present invention belongs to the technical field of pipe joint manufacturing, and specifically relates to a quick-change joint, which includes a male pipe and a female pipe that cooperate with each other. An axially elastic telescopic on-off switch is coaxially arranged inside the female pipe. A radial mechanical telescopic engaging device that cooperates with the male pipe is penetrated through the female pipe. An engaging portion that simultaneously cooperates with the axially elastic telescopic on-off switch and the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of one end of the male pipe. A limit switch for controlling the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of the female pipe. The present invention adopts the method of arranging an axially sliding limit switch on the outer surface of the female pipe to design a quick-change joint, which solves the problem that when the sliding sleeve is subjected to the frictional force of other surrounding objects, it is easy to squeeze the spring and cause the male pipe to fall off the female pipe.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipe joint manufacturing, and specifically relates to a quick-release joint. Background Art

[0002] Quick-release joints are devices widely used for connecting pipelines, with the performance of quick buckling and quick disassembly, and are closely related to some gas-related industries. There are two types of characteristics of quick-release joints on the current market. The first type is simple in structure, convenient to operate, with automatic buckling and ejection, but the airtight effect is not very ideal. Especially when the pressure is higher, the sealing effect is worse, and the action is inaccurate. The second type is complex in structure, slow to assemble, but has good airtightness, accurate action, and can be automatically buckled and ejected.

[0003] Chinese Patent CN201330906Y discloses a quick connector, which is composed of a fixed connector and a movable connector that are inserted and fitted together. The inner hole of the movable connector is an air inlet passage. The fixed connector includes a body and a sleeve threadedly assembled in the body. The inner hole of the fixed connector is composed of an insertion passage and an air inlet passage. A stop valve device is provided in the insertion passage. The valve seat of the stop valve device is mounted between the end of the sleeve extending into the body and the annular step on the inner wall of the body. The valve core of the one-way valve passes through the inner hole of the valve seat and is axially slidably assembled in the fixed connector. A sealing ring that is sealingly fitted with the inner hole of the valve seat is sleeved on the head of the valve core. When the movable connector is not inserted into the fixed connector, the compression spring mounted between the annular edge on the valve core and the valve seat positions the valve core, and the inner hole of the valve seat is closed by relying on the sealing ring. When the movable connector is inserted into the fixed connector, the movable connector overcomes the elastic force of the compression spring to push the valve core to move, so that the inner hole of the valve seat is opened. At the same time, the air hole on the valve core is communicated with the air inlet passage, so that the air outlet passage and the air inlet passage are conducted. A stepped annular groove is provided on the outer wall of the movable connector. Two tapered through holes extending in the radial direction are symmetrically provided on the outer wall of the sleeve. Steel balls are respectively assembled in the two tapered through holes. A sliding sleeve is slidably sleeved on the body. An annular groove is provided on the inner wall of the sliding sleeve. During the process of the movable connector being inserted into the fixed connector, when the steel balls respectively abut against the annular groove in the sliding sleeve and the annular groove in the movable connector, the movable connector and the fixed connector are locked. When unlocking, the sliding sleeve is pushed so that the steel balls are disengaged from the annular groove until they are opposite to the annular shoulder. At the same time, the movable connector moves outward under the action of the valve core spring, so that the steel balls abut against the annular shoulder of the sliding sleeve, and finally unlocking is achieved. The stop valve device of this quick connector can ensure the sealing effect of the entire quick connector. During the locking process, when the movable connector pushes the valve core to move inward, under the action of the spring mounted between an annular step on the inner wall of the sliding sleeve and the body, the conical surface at the annular shoulder of the sliding sleeve pushes the steel balls to move inward, and automatic locking can be achieved. However, during use, when the sliding sleeve is subjected to the frictional force of other surrounding objects, it is easy to squeeze the spring and cause the movable connector to fall off from the fixed connector. Therefore, it is necessary to design a quick connector that can prevent the sliding sleeve from sliding without being manually pushed. Summary of the Invention

[0004] Aiming at the shortcomings of the prior art, the object of the present invention is to design a quick-change connector by setting an axially sliding limit switch on the outer surface of the female head tube, which solves the problem that when the sliding sleeve is subjected to the frictional force of other surrounding objects, it is easy to squeeze the spring and cause the male head tube to fall off from the female head tube.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A quick-change joint, comprising a male head pipe and a female head pipe that cooperate with each other. An axially elastic telescopic on-off switch is coaxially arranged inside the female head pipe. A radial mechanical telescopic engaging device that cooperates with the male head pipe is penetrated and arranged on the female head pipe. An engaging portion that simultaneously cooperates with the axially elastic telescopic on-off switch and the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of one end of the male head pipe. A limit switch for controlling the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of the female head pipe.

[0007] Preferably, the limit switch includes a sleeve and a first spring. The sleeve is sleeved on the outer peripheral surface of the female head pipe. A first circular ring protrusion is coaxially arranged on the inner surface of the sleeve. A trigger is arranged on the end surface of the first circular ring protrusion facing one end of the female head pipe that cooperates with the male head pipe. A second circular ring protrusion is arranged on the outer circumferential surface of the female head pipe. The outer diameter of the second circular ring protrusion is smaller than the inner diameter of the sleeve. The first circular ring protrusion is between the second circular ring protrusion and one end of the female head pipe that cooperates with the male head pipe. A first spring is sleeved on the female head pipe between the first circular ring protrusion and the second circular ring protrusion. Two ends of the first spring are respectively abutted against the first circular ring protrusion and the second circular ring protrusion. A convex rib is axially arranged on the outer circumferential surface of the female head pipe. The convex rib is located on the side of the second circular ring protrusion facing away from the first circular ring protrusion. A chute that cooperates with the convex rib is arranged on the inner circumferential surface of one end of the sleeve facing away from the male head pipe. A limit ring is arranged on the outer circumferential surface of the female head pipe on the side of the first circular ring protrusion facing away from the second circular ring protrusion; when the first spring is in its natural length, the trigger triggers the radial mechanical telescopic engaging device, and the sleeve facing one end of the female head pipe that cooperates with the male head pipe abuts against the limit ring; a chute is axially arranged on the inner circumferential surface of the sleeve on the side of the first circular ring protrusion facing the second circular ring protrusion. One end of the chute facing away from the first circular ring protrusion extends outside the sleeve. A convex rib that cooperates with the chute is axially arranged on the outer circumferential surface of the female head pipe on the side of the second circular ring protrusion facing away from the first circular ring protrusion. The distance between the convex rib and the limit ring is equal to the length of the sleeve.

[0008] Preferably, the radial mechanical telescopic engaging device includes a first through hole and an engaging ball. The first through hole is radially arranged on the side wall of the female head pipe. The inner diameter of the middle section in the first through hole is larger than the inner diameter between the two ends. The engaging ball is located in the first through hole. The inner diameter between the two ends of the first through hole is smaller than the outer diameter of the engaging ball. The length of the first through hole is smaller than the outer diameter of the engaging ball.

[0009] Preferably, the axially sliding trigger is an inclined plane.

[0010] Preferably, the outer cross-section of the part of the female head tube where the convex ribs are provided is a regular polygon, the cross-section of the convex ribs is formed by two adjacent sides of the regular polygon, the inner diameter of the sleeve is greater than the distance from the center of the regular polygon to the side length, and the inner diameter of the sleeve is less than the distance from the center of the regular polygon to the vertex.

[0011] Preferably, rounded corners are provided at the vertices of the regular polygon.

[0012] Preferably, the axial elastic telescopic on-off switch includes an annular flange and a plug cylinder with one end open. The annular flange is coaxially arranged inside the female head tube. One side of the annular flange is connected to the plug cylinder through a second spring. A second through hole communicating with the inside of the plug cylinder is radially provided on the peripheral wall of the plug cylinder. A preset gap is provided between the second through hole and the opening of the plug cylinder. A sealing ring that is hermetically fitted with the inner surface of the annular flange is provided on the plug cylinder between the closed end of the plug cylinder and the second through hole.

[0013] Preferably, the engaging portion includes a limiting convex ring and an extrusion tube. The extrusion tube is arranged at one end of the male head tube. The inner diameter of the extrusion tube is smaller than the outer diameter of the plug cylinder. The outer diameter of the extrusion tube is smaller than the inner diameter of the female head tube. The limiting convex ring is arranged between the two ends of the extrusion tube. The outer diameter of the male head tube is equal to the inner diameter of the female head tube. The outer diameter of the limiting convex ring is smaller than or equal to the inner diameter of the female head tube. The distance between the limiting convex ring and the end of the male head tube facing the extrusion tube is smaller than or equal to the diameter of the engaging ball.

[0014] Preferably, the female head tube includes a tube body and a connecting tube. The right end of the tube body is matched with the male head tube. A first thread is provided on the outer surface of the left end of the tube body. A second thread that is matched with the first thread is provided on the inner surface of the right end of the connecting tube. The convex ribs are located on the connecting tube. The outer cross-section of the connecting tube is a regular polygon. The part between the right end of the connecting tube and the left end of the convex ribs forms the second circular ring protrusion. The first through hole is provided on the tube body.

[0015] Preferably, a spring rotation friction reducer is further included. A spring rotation friction reducer is arranged between the first spring and the first circular ring protrusion and between the first spring and the second circular ring protrusion respectively.

[0016] Preferably, a connector is provided on the first spring. The first spring is fixedly connected to the spring rotation friction reducer through the connector.

[0017] Preferably, the connector is a third through hole. At least one third through hole is provided at the end of the first spring. The axis of the third through hole is parallel to the axis of the first spring.

[0018] Preferably, the spring rotation friction reducer includes rolling balls, a mounting ball seat, a mounting plate, and screws. The mounting ball seat is provided with a spherical mounting cavity. The bottom surface of the mounting ball seat is provided with an opening communicating with the spherical mounting cavity. The rolling balls are located in the spherical mounting cavity. The distance between the side of the spherical mounting cavity facing away from the opening and the bottom surface of the mounting ball seat is less than the diameter of the rolling balls. The radius of the opening of the spherical mounting cavity is less than the radius of the rolling balls. The side of the mounting ball seat facing away from the opening of the spherical mounting cavity is fixedly connected to the mounting plate. The mounting plate is provided with threaded holes matching the screws. The axis of the threaded holes is coaxial with the axis of the opening of the spherical mounting cavity. The outer diameter of the screws is less than the inner diameter of the third through holes.

[0019] Preferably, it further includes a connecting seat. The connecting seat is provided with two first rotating shafts and two second rotating shafts. The axis of the first rotating shaft is parallel to the axis of the opening of the spherical mounting cavity. The axis of the second rotating shaft is perpendicular to the axis of the first rotating shaft and perpendicular to the lower surface of the mounting plate. The connecting seat is respectively rotatably connected to a connecting block through the two first rotating shafts. Each connecting block is connected to one of the second rotating shafts at a position far from the connecting seat. A number of the third through holes are provided along the outer ring of the spiral wire forming the first spring. Each third through hole is fixedly connected to a mounting plate through the screw. The connecting seat is arranged between the two mounting plates on two adjacent third through holes. The connecting seat is rotatably connected to the two mounting plates on two adjacent third through holes through the two second rotating shafts respectively.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The present invention designs a quick-change joint by setting an axial sliding limit switch on the outer surface of the female head tube, solving the problem that when the sliding sleeve is subject to the friction of other surrounding objects, it is easy to squeeze the spring and cause the male head tube to fall off the female head tube.

[0022] 2. In the present invention, after the sleeve moves to the right, the inclined surface squeezes the engaging ball, causing the engaging ball to protrude toward the inside of the female head tube, thereby clamping the engaging portion on the male head tube; when the sleeve moves to the left, the inclined surface disengages from the engaging ball, enabling the user to easily pull out the male head tube from the female head tube.

[0023] 3. The present invention uses the rib edge on the female head tube as the convex rib, which is more solid than the method of setting convex ribs on the outer surface of the female head tube. At the same time, it reduces the manufacturing process difficulty, reduces the manufacturing cost, and is convenient for popularization. Preferably, the regular polygon is a regular hexagon or a regular octagon, which can make the root of the convex rib thicker than the top, thus avoiding damage to the convex rib during collision.

[0024] 4. A spring rotation friction reducer is provided between the first spring and the first ring protrusion and between the first spring and the second ring protrusion, so that during the axial rotation of the sleeve, the friction between the first ring protrusion and the second ring protrusion and the end of the first spring is reduced, making the sleeve rotate more smoothly during axial rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of the present invention

[0026] Figure 2 is this Figure 1 schematic structural diagram of the front side;

[0027] Figure 3 is Figure 2 sectional view taken along line A-A in

[0028] Figure 4 is a schematic structural diagram of an embodiment of the female head tube in the present invention;

[0029] Figure 5 is a schematic structural diagram of an embodiment of the sleeve in the present invention;

[0030] Figure 6 is a schematic structural diagram of an embodiment of the plug cylinder in the present invention;

[0031] Figure 7 is a schematic structural diagram of an embodiment of the spring rotation friction reducer in the present invention;

[0032] Figure 8 is a schematic structural diagram of the bottom of the spring rotation friction reducer in an embodiment of the present invention;

[0033] Figure 9 is a connection relationship diagram of the spring rotation friction reducer and the first spring in an embodiment of the present invention.

[0034] Wherein: 1, male head tube; 2, female head tube; 3, sleeve; 4, first spring; 5, first ring protrusion; 6, second ring protrusion; 7, convex rib; 8, chute; 9, limit ring; 10, first through hole; 11, engaging ball; 12, inclined surface; 13, annular flange; 14, plug cylinder; 15, second spring; 16, second through hole; 17, sealing ring; 18, limit convex ring; 19, extrusion tube; 20, tube body; 21, connecting tube; 22, third through hole; 23, rolling ball; 24, mounting ball seat; 25, mounting plate; 26, screw; 27, spherical mounting cavity; 28, threaded hole; 29, connecting seat; 30, first rotating shaft; 31, second rotating shaft; 32, connecting block. DETAILED DESCRIPTION OF THE INVENTION

[0035] See Figures 1-9 , a quick-change joint, including a male head tube 1 and a female head tube 2 that cooperate with each other. An axially elastic telescopic on-off switch is coaxially provided inside the female head tube 2. A radial mechanical telescopic coupler that cooperates with the male head tube is provided through the female head tube. A coupling portion that cooperates with both the axially elastic telescopic on-off switch and the radial mechanical telescopic coupler is provided on the outer peripheral surface of one end of the male head tube 1. A limit switch for controlling the radial mechanical telescopic coupler is provided on the outer peripheral surface of the female head tube 2.

[0036] In this embodiment, when in use, the end of the male head tube 1 provided with the coupling portion is inserted into the female head tube 2. The coupling portion on the male head tube 1 simultaneously triggers the axially elastic telescopic on-off switch and the radial mechanical telescopic coupler provided on the female head tube 2, so that the inside of the female head tube 2 is communicated with the inside of the male head tube 1 while locking the male head tube 1 and the female head tube 2 together. Then the user switches to the limit mode by axially sliding the limit switch to limit the radial mechanical telescopic coupler, so that the radial mechanical telescopic coupler is in a state of clamping the coupling portion on the male head tube 1 with the female head tube 2, thereby preventing the male head tube 1 from falling off the female head tube 2; when it is necessary to separate the male head tube 1 and the female head tube 2, the user axially slides the limit switch again to release the restriction on the radial mechanical telescopic coupler, so that the male head tube 1 falls off the female head tube 2.

[0037] As a preferred manner, the limit switch includes a sleeve 3 and a first spring 4. The sleeve 3 is sleeved on the outer peripheral surface of the female head tube 2. A first circular ring protrusion 5 is coaxially provided on the inner surface of the sleeve 3. A sliding trigger is arranged on the end surface of the first circular ring protrusion 5 facing the end of the female head tube 2 that cooperates with the male head tube 1. A second circular ring protrusion 6 is provided on the outer circumferential surface of the female head tube 2, and the outer diameter of the second circular ring protrusion 6 is smaller than the inner diameter of the sleeve 3. The first circular ring protrusion 5 is between the second circular ring protrusion 6 and the end of the female head tube 2 that cooperates with the male head tube 1. A first spring 4 is sleeved on the female head tube 2 between the first circular ring protrusion 5 and the second circular ring protrusion 6. The two ends of the first spring 4 are respectively abutted against the first circular ring protrusion 5 and the second circular ring protrusion 6. A convex rib 7 is axially provided on the outer circumferential surface of the female head tube 2, and the convex rib 7 is located on the side of the second circular ring protrusion 6 facing away from the first circular ring protrusion 5. A chute 8 that cooperates with the convex rib 7 is provided on the inner circumferential surface of the end of the sleeve 3 facing away from the male head tube 1. A limit ring 9 is provided on the outer circumferential surface of the female head tube 2 on the side of the first circular ring protrusion 5 facing away from the second circular ring protrusion 6; when the first spring 4 is in its natural length, the trigger triggers the radial mechanical expansion and contraction coupler, and the end of the sleeve 3 facing the end of the female head tube that cooperates with the male head tube abuts against the limit ring 9; a chute 8 is axially provided on the inner circumferential surface of the sleeve 3 on the side of the first circular ring protrusion 5 facing the second circular ring protrusion 6, and the end of the chute 8 facing away from the first circular ring protrusion 5 extends outside the sleeve 3. A convex rib 7 that cooperates with the chute 8 is axially provided on the outer circumferential surface of the female head tube 2 on the side of the second circular ring protrusion 6 facing away from the first circular ring protrusion 5. The distance between the convex rib 7 and the limit ring 9 is equal to the length of the sleeve 3.

[0038] After such a setting, when the first spring 4 elongates and the sleeve 3 moves to the first ring protrusion 5, when the trigger triggers the radial mechanical expansion and contraction coupler, the radial mechanical expansion and contraction coupler locks the male head tube 1 and the female head tube 2 together. At the same time, since the engaging portion on the male head tube 1 triggers the axial elastic expansion and contraction on-off switch, the inside of the male head tube 1 communicates with the inside of the female head tube 2, and at this time, the convex rib 7 is outside the sliding groove 8; then, the user manually rotates the sleeve 3 by a certain angle around the central axis of the sleeve 3, so that the sliding groove 8 and the convex rib 7 are not collinear. In this state, the sleeve 3 is blocked by the end of the convex rib 7 and the limiting ring 9, so that the sleeve 3 cannot move axially. Therefore, the trigger will not leave the radial mechanical expansion and contraction coupler, making the radial mechanical expansion and contraction coupler always hold the engaging portion of the male head tube 1, and further preventing the male head tube 1 from falling off the female head tube 2; when it is necessary to disconnect the male head tube 1 and the female head tube 2, the user only needs to rotate the sleeve 3 by a certain angle around the central axis of the sleeve 3 so that the convex rib 7 and the sliding groove 8 are collinear. In this state, the sleeve 3 can move along the axis of the sleeve 3, and the trigger can be made to leave the radial mechanical expansion and contraction coupler (without triggering the radial mechanical expansion and contraction coupler) by moving the sleeve 3, so that the radial mechanical expansion and contraction coupler no longer engages the engaging portion on the male head tube 1, thus enabling the male head tube 1 and the female head tube 2 to be detached from each other.

[0039] As a preferred method, the radial mechanical expansion and contraction coupler includes a first through hole 10 and a clamping ball 11. The first through hole 10 is radially provided on the side wall of the female head tube 2. The inner diameter of the middle section of the first through hole 10 is larger than the inner diameter between the two ends. The clamping ball 11 is located in the first through hole 10. The inner diameter between the two ends of the first through hole 10 is smaller than the outer diameter of the clamping ball 11. The length of the first through hole 10 is smaller than the outer diameter of the clamping ball 11. The axial sliding trigger is an inclined surface 12. After such a setting, as Figure 3 shown, after the sleeve 1 moves to the right, the inclined surface 12 squeezes the clamping ball 11, making the side of the clamping ball 11 protruding toward the inside of the female head tube 2, so as to clamp the engaging portion on the male head tube 1; when the sleeve 1 moves to the left, the inclined surface 12 disengages from the clamping ball 11, enabling the user to easily pull out the male head tube 1 from the female head tube 2.

[0040] As a preferred embodiment, the outer cross-section of the part of the female head tube 2 where the convex ribs 7 are provided is a regular polygon. The cross-section of the convex rib 7 is formed by two adjacent sides of the regular polygon. The inner diameter of the sleeve 3 is greater than the distance from the center of the regular polygon to the side length, and the inner diameter of the sleeve 3 is less than the distance from the center of the regular polygon to the vertex. In this way, using the rib edges on the female head tube 2 as convex ribs is stronger compared to the method of setting convex ribs 7 on the outer surface of the female head tube 2. At the same time, it reduces the processing difficulty during manufacturing, lowers the manufacturing cost, and is convenient for popularization. Preferably, the regular polygon is a regular hexagon or a regular octagon, which can make the root of the convex rib 7 thicker than the top, thus avoiding damage to the convex rib 7 during collisions.

[0041] Preferably, the above regular polygon is a regular hexagon or a regular octagon. After such a setting, since the included angle between two adjacent sides of a regular hexagon or a regular octagon is much larger than that of a regular quadrilateral or a regular pentagon, it is an obtuse angle, and the two adjacent sides form the two side edges of the cross-section of the convex rib 7. This setting can prevent the convex rib 7 from being damaged during use, thus affecting the fit between the convex rib 7 and the chute 8 on the sleeve 3. If the included angle between the two sides of the above regular polygon is small, when encountering an impact, it is even possible for the convex rib 7 to fall off from the female head tube 2.

[0042] As a preferred embodiment, a fillet is provided at the vertex of the regular polygon.

[0043] As a preferred embodiment, the axially elastically telescopic on-off switch includes an annular flange 13 and a plug cylinder 14 with one end open. The annular flange 13 is coaxially arranged inside the female head tube 2. One side of the annular flange 13 is connected to the plug cylinder 14 through a second spring 15. A second through hole 16 communicating with the inside of the plug cylinder 14 is radially provided on the peripheral wall of the plug cylinder 14. A preset gap is provided between the second through hole 16 and the opening of the plug cylinder 14. A sealing ring 17 that is hermetically fitted with the inner surface of the annular flange 13 is provided on the plug cylinder 14 between the closed end of the plug cylinder 14 and the second through hole 16. After such a setting, as Figure 2 shown, after the male head tube 1 is inserted into the female head tube 2, the male head tube 1 presses against the plug cylinder 14, causing the plug cylinder 14 to move to the left ( Figure 3 left in ), so that the second through hole 16 connects the spaces on both sides of the annular flange 13 inside the female head tube 2, facilitating the flow of fluid (gas or liquid).

[0044] As a preferred embodiment, the engaging portion includes a limiting convex ring 18 and an extrusion tube 19. The extrusion tube 19 is provided at one end of the male head tube 1. The inner diameter of the extrusion tube 19 is smaller than the outer diameter of the plug cylinder 14, and the outer diameter of the extrusion tube 19 is smaller than the inner diameter of the female head tube 2. The limiting convex ring 18 is provided between the two ends of the extrusion tube 19. The outer diameter of the male head tube 1 is equal to the inner diameter of the female head tube 2, and the outer diameter of the limiting convex ring 18 is smaller than or equal to the inner diameter of the female head tube 2. The distance between the limiting convex ring 18 and the end of the male head tube 1 facing the extrusion tube 19 is smaller than or equal to the diameter of the engaging ball 11. After such a setting, as Figure 2 shown, after the sleeve 4 moves to the right ( Figure 3 the right in

[0045] ), the engaging ball 11 is extruded, so that the part of the engaging ball 11 facing the inside of the female head tube 2 is located in the area between the limiting convex ring 18 and the male head tube 1, thereby locking the male head tube 1 and the female head tube 2 together.

[0046] As a preferred embodiment, as Figures 7 to 9 shown, since there is friction between the first ring protrusion 5 and the second ring protrusion 5 and the ends of the first spring 4 during the axial rotation of the sleeve 3, which may affect the rotation of the sleeve 3. Therefore, the present invention further includes a spring rotation friction reducer, and a spring rotation friction reducer is provided between the first spring 4 and the first ring protrusion 5 and between the first spring 4 and the second ring protrusion 6 respectively.

[0047] As a preferred embodiment, a connector is provided on the first spring. The first spring 4 is fixedly connected to the spring rotation friction reducer through the connector. In this way, the spring rotation friction reducer is connected to the first spring 4 through the connector.

[0048] As a preferred embodiment, the connector is a third through hole 22. At least one third through hole 22 is provided at the end of the first spring 4, and the axis of the third through hole 22 is parallel to the axis of the first spring 4.

[0049] As a preferred embodiment, the spring rotational friction reducer includes a rolling ball 23, a mounting ball seat 24, a mounting plate 25, and a screw 26. The mounting ball seat 24 is provided with a spherical mounting cavity 27. The bottom surface of the mounting ball seat 24 is provided with an opening communicating with the spherical mounting cavity 27. The rolling ball 23 is located in the spherical mounting cavity 27. The distance between the side of the spherical mounting cavity 27 facing away from the opening and the bottom surface of the mounting ball seat 24 is less than the diameter of the rolling ball 23. The radius of the opening of the spherical mounting cavity 27 is less than the radius of the rolling ball 23. The side of the mounting ball seat 24 facing away from the opening of the spherical mounting cavity 27 is fixedly connected to the mounting plate 25. The mounting plate 25 is provided with a threaded hole 28 that cooperates with the screw 26. The axis of the threaded hole 28 is coaxial with the axis of the opening of the spherical mounting cavity 27. The outer diameter of the screw 26 is less than the inner diameter of the third through hole 22. After such a setting, the side of the rolling ball 23 facing away from the mounting ball seat 24 contacts the first annular protrusion 5 or the second annular protrusion 6, thereby reducing the friction.

[0050] As a preferred embodiment, it further includes a connecting seat 29. The connecting seat 29 is provided with two first rotating shafts 30 and two second rotating shafts 31. The axis of the first rotating shaft 30 is parallel to the axis of the opening of the spherical mounting cavity 27. The axis of the second rotating shaft 31 is perpendicular to the axis of the first rotating shaft 30 and perpendicular to the lower surface of the mounting plate 25. The connecting seat 29 is respectively rotatably connected to a connecting block 32 through the two first rotating shafts 30. Each connecting block 32 is connected to one of the second rotating shafts 31 at a position away from the connecting seat 29. A number of the third through holes 22 are provided along the outer ring of the helical wire forming the first spring 4 on the first spring 4. Each third through hole 22 is fixedly connected to a mounting plate 25 through the screw 26. The connecting seat 29 is arranged between the two mounting plates 25 on two adjacent third through holes 22. The connecting seat is rotatably connected to the two mounting plates 25 on two adjacent third through holes 22 through the two second rotating shafts 31 respectively. In this way, a number of spring rotational friction reducers are connected by the connecting seat 29, so that when the first spring 4 is compressed, both ends of the first spring 4 are covered with rolling balls 23, thereby further reducing the frictional force. When the first spring 4 is not completely compressed, if the rolling ball 23 at the end of the wire forming the first spring 4 and the mounting ball seat 24 are damaged, the purpose of reducing friction can still be achieved by replacing the rolling ball 23 at other positions on the first spring 4, thus facilitating the troubleshooting when a failure occurs.

Claims

1. A quick-change joint, comprising a male head tube (1) and a female head tube (2) that cooperate with each other, characterized in that, An axially elastic telescopic on-off switch is coaxially arranged inside the female head tube (2). A radial mechanical telescopic engaging device that cooperates with the male head tube (1) is arranged through the female head tube (2). An engaging portion that simultaneously cooperates with the axially elastic telescopic on-off switch and the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of one end of the male head tube (1). A limit switch for controlling the radial mechanical telescopic engaging device is arranged on the outer peripheral surface of the female head tube (2); The limit switch includes a sleeve (3) and a first spring (4). The sleeve (3) is sleeved on the outer peripheral surface of the female head tube (2). A first circular ring protrusion (5) is coaxially arranged on the inner surface of the sleeve (3). A trigger is arranged on the end surface of the first circular ring protrusion (5) facing one end of the female head tube (2) that cooperates with the male head tube (1). A second circular ring protrusion (6) is arranged on the outer circumferential surface of the female head tube (2). The outer diameter of the second circular ring protrusion (6) is smaller than the inner diameter of the sleeve (3). The first circular ring protrusion (5) is between the second circular ring protrusion (6) and one end of the female head tube (2) that cooperates with the male head tube (1). A first spring (4) is sleeved on the female head tube (2) between the first circular ring protrusion (5) and the second circular ring protrusion (6). Two ends of the first spring (4) are respectively abutted against the first circular ring protrusion (5) and the second circular ring protrusion (6). A convex rib (7) is axially arranged on the outer circumferential surface of the female head tube (2). The convex rib (7) is located on the side of the second circular ring protrusion (6) opposite to the first circular ring protrusion (5). A chute (8) that cooperates with the convex rib (7) is arranged on the inner circumferential surface of one end of the sleeve (3) opposite to the male head tube (1). A limit ring (9) is arranged on the outer circumferential surface of the female head tube (2) on the side of the first circular ring protrusion (5) opposite to the second circular ring protrusion (6); when the first spring (4) is in its natural length, the trigger triggers the radial mechanical telescopic engaging device, and the end of the sleeve (3) facing one end of the female head tube (2) that cooperates with the male head tube (1) abuts against the limit ring (9); a chute (8) is axially arranged on the inner circumferential surface of the sleeve (3) on the side of the first circular ring protrusion (5) facing the second circular ring protrusion (6). The end of the chute (8) opposite to the first circular ring protrusion (5) extends outside the sleeve (3). A convex rib (7) that cooperates with the chute (8) is axially arranged on the outer circumferential surface of the female head tube (2) on the side of the second circular ring protrusion (6) opposite to the first circular ring protrusion (5). The distance between the convex rib (7) and the limit ring (9) is equal to the length of the sleeve (3); The radial mechanical expansion and engagement coupler includes a first through hole (10) and engagement balls (11). The first through hole (10) is radially provided on the side wall of the female head tube (2). The inner diameter of the middle section in the first through hole (10) is larger than the inner diameter between both ends. The engagement balls (11) are located in the first through hole (10). The inner diameter between both ends of the first through hole (10) is smaller than the outer diameter of the engagement balls (11). The length of the first through hole (10) is smaller than the outer diameter of the engagement balls (11). The trigger is an inclined surface (12). It further includes a spring rotation friction reducer, and a spring rotation friction reducer is provided between the first spring (4) and the first ring protrusion (5) and between the first spring (4) and the second ring protrusion (6) respectively.

2. The quick-change joint according to claim 1, characterized in that, The outer cross-section of the part of the female head tube (2) where the convex ribs (7) are provided is a regular polygon. The cross-section of the convex ribs (7) is composed of two adjacent sides of the regular polygon. The inner diameter of the sleeve (3) is larger than the distance from the center of the regular polygon to the side length, and the inner diameter of the sleeve (3) is smaller than the distance from the center of the regular polygon to the vertex.

3. The quick-change joint according to claim 2, wherein, Round corners are provided at the vertices of the regular polygon.

4. The quick-change connector according to claim 1, characterized in that, The axial elastic expansion and disconnection switch includes an annular flange (13) and a plug cylinder (14) with one end open. The annular flange (13) is coaxially provided inside the female head tube (2). One side of the annular flange (13) is connected to the plug cylinder (14) through a second spring (15). A second through hole (16) communicating with the inside of the plug cylinder (14) is radially provided on the peripheral wall of the plug cylinder (14). A preset gap is provided between the second through hole (16) and the opening of the plug cylinder (14). A sealing ring (17) in airtight fit with the inner surface of the annular flange (13) is provided on the plug cylinder (14) between the closed end of the plug cylinder (14) and the second through hole (16).

5. The quick-change joint according to claim 4, characterized in that, The engagement part includes a limit convex ring (18) and an extrusion tube (19). The extrusion tube (19) is provided at one end of the male head tube (1). The inner diameter of the extrusion tube (19) is smaller than the outer diameter of the plug cylinder (14). The outer diameter of the extrusion tube (19) is smaller than the inner diameter of the female head tube (2). The limit convex ring (18) is provided between both ends of the extrusion tube (19). The outer diameter of the male head tube (1) is equal to the inner diameter of the female head tube (2). The outer diameter of the limit convex ring (18) is smaller than or equal to the inner diameter of the female head tube (2). The distance between the limit convex ring (18) and the end of the male head tube (1) facing the extrusion tube (19) is smaller than or equal to the diameter of the engagement balls (11).

6. The quick-change joint according to claim 2, wherein, The female head tube includes a tube body (20) and a connecting tube (21). The right end of the tube body (20) is fitted with the male head tube (1). A first thread is provided on the outer surface of the left end of the tube body (20). A second thread that mates with the first thread is provided on the inner surface of the right end of the connecting tube (21). The convex rib (7) is located on the connecting tube (21). The outer cross-section of the connecting tube (21) is a regular polygon. A part between the right end of the connecting tube (21) and the left end of the convex rib (7) forms the second circular ring protrusion (6). The first through hole (10) is provided on the tube body (20).

7. The quick-change joint according to claim 6, characterized in that, A connector is provided on the first spring. The first spring (4) is fixedly connected to the spring rotation friction reducer through the connector.

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