A device for quickly replacing the mandrel of a pipe fitting

Abstract

The present invention discloses a quick replacement device for a pipe fitting mandrel, which includes a pull rod joint, a mandrel pull rod, and a plurality of positioning inserts slidably mounted on the mandrel. The pull rod joint includes a pulling member and a quick-release member. The pulling member includes a limiting portion and a connecting portion slidably connected to the limiting portion. The connecting portion is fixedly connected to the mandrel pull rod, and the outer diameter of the connecting portion is not less than the outer diameter of the limiting portion. When the mandrel needs to be withdrawn from the conduit, the limiting portion is pushed through the plurality of positioning inserts so that the positioning inserts block the return path of the limiting portion. Then, the limiting portion is pulled back in the opposite direction to withdraw the mandrel from the conduit. When it is necessary to separate the pull rod joint from the mandrel, the quick-release member is pushed through the plurality of positioning inserts, and the mandrel pull rod is pulled back in the opposite direction, so that the positioning inserts move outward along the tapered surface of the quick-release member to separate the pull rod joint from the mandrel. In this way, the quick installation and disassembly of the mandrel and the pull rod can be realized quickly.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and particularly to a device for quickly replacing a mandrel of a pipe fitting. Background Art

[0002] There are many metal hollow pipe components on airplanes and rockets, commonly known as "ducts". Ducts are mainly used to transport various liquids and gases, support the fuel, power, etc. required for the flight of airplanes and rockets, and complete various work tasks. They are very important parts on airplanes and rockets. There are a very large number of types of ducts used in airplanes and rockets, and the quantity of each type of pipe fitting used is very small. Therefore, the mold needs to be frequently replaced during the bending process. Since the ducts in airplanes and rockets undertake important tasks such as fuel input, mechanism opening, pressure control, and environment regulation during preparation, any failure or damage in any part may lead to major tragedies such as "plane crash and death of passengers" and "rocket explosion and destruction of satellites", and is directly related to the safety of officers, soldiers, and passengers. The existing mandrel is usually installed by a threaded connection method. When there are many wall thickness specifications of the ducts that need to be bent, it is necessary to frequently replace them. Especially for large-diameter mandrels, when the single-piece weight cannot be lifted and disassembled by one person, the work of disassembling and installing the mandrel will hold back the entire production and processing process and cause a certain impact. Summary of the Invention

[0003] In order to solve the problem in the prior art that when manufacturing small batches of bent ducts, the mandrel of the formed duct needs to be frequently replaced, resulting in low production efficiency, the purpose of the present invention is to provide a device for quickly replacing a mandrel of a pipe fitting, which can quickly complete the connection and disassembly with the mandrel and quickly extract the mandrel from the duct to improve the efficiency when manufacturing small batches of bent ducts.

[0004] To achieve the above object, the present invention adopts the following technical solutions: It includes a tie rod joint and a mandrel tie rod, and the tie rod joint is installed at the end of the mandrel tie rod; one end of the mandrel is a forming end inserted into the catheter, and the other end of the mandrel is a connection end connected to the replacement device. A plurality of positioning plugs are installed on the connection end, and the plurality of positioning plugs are arranged around the axis of the mandrel. The positioning plugs are installed on the mandrel and can slide radially along the mandrel; the tie rod joint includes a pulling member and a quick-release member. The pulling member includes a limiting portion and a connecting portion. One end of the connecting portion is fixedly connected to the limiting portion, and the other end of the connecting portion is fixedly connected to the mandrel tie rod. The quick-release member is sleeved on the connecting portion, and the quick-release member is located between the limiting portion and the mandrel tie rod; the outer surface of the limiting portion includes a first conical surface, a first transition surface parallel to the axis, and a first limiting surface perpendicular to the axis; the outer surface of the quick-release member includes a second conical surface, a second transition surface parallel to the axis, and a second limiting surface perpendicular to the axis. The second conical surface and the second limiting surface are connected by the second transition surface; a first spring is sleeved on the connecting portion, and both ends of the first spring are connected to the limiting portion and the quick-release member respectively. The first spring can push the limiting portion and the quick-release member apart; a quick-connection groove is formed on the connection end of the mandrel, and a plurality of radially extending limiting holes are formed on the mandrel. The plurality of limiting holes are all communicated with the quick-connection groove; the positioning plug is inserted into the limiting hole, and a second spring is sleeved on the positioning plug. One end of the second spring abuts against the positioning plug, and the other end of the second spring abuts against the mandrel. The second spring can drive the positioning plug to extend into the quick-connection groove; the positioning plug further includes an inclined surface, a third limiting surface, and a third transition surface parallel to the axis. The third limiting surface and the inclined surface are connected by the third transition surface. When the positioning plug is inserted between the limiting portion and the quick-release member, the third limiting surface abuts against the first limiting surface.

[0005] Preferably, a receiving groove is formed on the first limiting surface, and a limiting protrusion matching the receiving groove is protruded on the second limiting surface.

[0006] Preferably, the positioning plug further includes an arc surface, and the arc surface and the third transition surface are connected by the inclined surface. When the positioning plug is inserted between the limiting portion and the quick-release member, the arc surface can abut against the connection portion of the second transition surface and the second limiting surface of the quick-release member.

[0007] Preferably, the axial lengths of the first transition surface, the third transition surface, and the second transition surface decrease in sequence.

[0008] Preferably, the radius of the first transition surface is the same as the radius of the second transition surface.

[0009] Preferably, the positioning plug further includes a third limiting surface and an inclined surface. The third limiting surface is perpendicular to the axis, and the third limiting surface and the inclined surface are connected by the third transition surface.

[0010] Preferably, a positioning piece is sleeved on the positioning plug-in, the positioning piece is fixedly connected to the mandrel, a retaining ring is fixed on the positioning plug-in, the retaining ring is located outside the positioning piece, and two ends of the second spring respectively abut against the positioning plug-in and the positioning piece.

[0011] The beneficial effect of the technical solution of the present invention is that the connection and disassembly of the pull rod joint and the mandrel can be quickly completed by a pushing and pulling method, and the mandrel can be quickly withdrawn from the catheter during the pushing and pulling process. Moreover, the above structure is applicable to mandrels of various specifications, that is to say, when forming catheters of different specifications, the connection between the mandrel and the pull rod can be completed by one pull rod joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the connection structure of the replacement device and the mandrel;

[0013] Figure 2 Schematic diagram of the structure of the replacement device and the mandrel in the unconnected state;

[0014] Figure 3 Schematic diagram of the connection structure of the replacement device and the mandrel when the replacement device is inserted into the mandrel;

[0015] Figure 4 Schematic diagram of the connection structure of the replacement device and the mandrel when the mandrel is withdrawn from the catheter;

[0016] Figure 5 Schematic diagram of the connection structure of the replacement device and the mandrel when the replacement device is removed from the mandrel;

[0017] Figure 6 Schematic diagram of the structure of the pull rod structure Figure 1 ;

[0018] Figure 7 Schematic diagram of the structure of the pull rod structure Figure 2 ;

[0019] Figure 8 Schematic diagram of the connection structure of the positioning plug-in and the second spring;

[0020] Figure 9 Schematic diagram of the structure of the positioning plug-in;

[0021] Figure 10 Schematic diagram of the structure of the limiting member Figure 1 ;

[0022] Figure 11 Schematic diagram of the structure of the limiting member Figure 2 ;

[0023] Figure 12 Schematic diagram of the structure of the quick-release member Figure 1 ;

[0024] Figure 13 Structural schematic of the quick-release part Figure 2 ;

[0025] Figure 14 Structural schematic diagram of the mandrel'

[0026] Figure 15 Structural schematic diagram of the connection between the replacement device and the mandrel in Embodiment 2;

[0027] Figure 16 For Figure 15 Enlarged view at A in

[0028] Reference numerals: 1, mandrel; 11, quick-connect groove; 12, connection hole; 13, limit hole; 2, mandrel pull rod; 3, pull-out part; 31, second connection part; 32, first connection part; 33, limit part; 331, first conical surface; 332, first transition surface; 333, first limit surface; 334, accommodation groove; 4, quick-release part; 41, inner hole; 43, second conical surface; 44, second transition surface; 45, second limit surface; 46, limit protrusion; 5, positioning plug-in; 51, insertion part; 511, third transition surface; 512, inclined surface; 513, third limit surface; 52, positioning part; 521, clamping groove; 53, retaining ring; 54, positioning piece; 55, second spring; 6, first spring. Detailed implementation manners

[0029] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more, unless otherwise clearly defined.

[0032] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0034] In the following embodiments, the orientation described is Figure 1 subject to Figure 1 wherein, taking the position of the mandrel as the left, the position of the pull rod as the right, and the axis of the mandrel as the inside. Embodiment 1

[0035] As Figures 1-5 shown, a quick replacement device for a pipe fitting mandrel includes a pull rod joint and a mandrel pull rod 2, and the pull rod joint is mounted at the end of the mandrel pull rod 2; as Figure 14 shown, one end of the mandrel 1 is a forming end inserted into a conduit, and the other end of the mandrel 1 is a connection end for connecting the replacement device. As Figures 2-5 shown, a plurality of positioning inserts are mounted on the connection end, and the plurality of positioning inserts are arranged around the axis of the connection end. The positioning inserts are mounted on the mandrel 1, and the positioning insert 5 can slide radially along the mandrel 1; as Figures 2-6As shown, the drawbar joint includes a draw member 3 and a quick-release member 4. The draw member 3 includes a limiting portion 33 and a connecting portion. One end of the connecting portion is fixedly connected to the limiting portion 33, and the other end of the connecting portion is fixedly connected to the mandrel drawbar 2. The quick-release member 4 is sleeved on the connecting portion, and the quick-release member 4 is located between the limiting portion 33 and the mandrel drawbar 2;

[0036] As Figure 6 , Figure 7 , Figure 10 , Figure 11 , Figure 12 and Figure 13 As shown, the outer surface of the limiting portion 33 includes a first conical surface 331 and a first limiting surface 333 arranged radially; the outer surface of the quick-release member 4 includes a second conical surface 43 and a second limiting surface 45 arranged radially. The perpendicular distance from the second conical surface 43 to the axis of the mandrel 1 is not less than the perpendicular distance from the first conical surface 331 to the axis of the mandrel 1;

[0037] When the mandrel 1 is connected to the mandrel: Push the mandrel drawbar 2 to make the limiting portion 33 simultaneously push against a plurality of positioning inserts 5, so that the plurality of positioning inserts 5 slide outward along the first conical surface 331 of the limiting portion 33. When the limiting portion 33 passes through between the plurality of positioning inserts 5, the plurality of positioning inserts 5 move toward the axis of the mandrel 1, so that the plurality of positioning inserts 5 are inserted between the limiting portion 33 and the quick-release portion; then pull the mandrel drawbar 2 in the reverse direction to make the first limiting surface 333 of the limiting portion 33 abut against the positioning insert 5, and continue to pull the mandrel drawbar 2 to extract the mandrel 1 from the catheter through the limiting portion 33 and the plurality of positioning inserts 5;

[0038] When it is necessary to separate the drawbar joint from the mandrel 1: Push the mandrel drawbar 2 to make the second conical surface 43 of the quick-release portion of the drawbar joint abut against the positioning insert 5, and continue to push the mandrel drawbar 2 to make the positioning insert 5 slide outward from the mandrel 1. When the quick-release portion of the drawbar joint passes through the plurality of positioning inserts 5, the plurality of positioning inserts 5 move toward the axis of the mandrel 1, so that the plurality of positioning inserts 5 are inserted between the quick-release portion and the mandrel drawbar 2; then pull the mandrel drawbar 2 in the reverse direction to make the positioning insert 5 abut against the second conical surface 43 of the quick-release portion, and continue to pull the mandrel drawbar 2 to make the quick-release portion approach the limiting portion 33. When the first limiting surface 333 of the limiting portion 33 abuts against the second limiting surface 45 of the quick-release member 4, the positioning insert 5 moves outward along the second conical surface 43 of the quick-release member 4. When the quick-release portion moves out of the plurality of positioning inserts 5, the limiting portion 33 also moves into the plurality of positioning inserts 5. When the quick-release portion moves out of the plurality of positioning inserts 5, the limiting portion 33 has already moved into the plurality of positioning inserts 5. Continue to pull the mandrel drawbar 2 to extract the limiting portion 33 of the drawbar joint from the plurality of positioning inserts 5.

[0039] With the above-mentioned device and method, the connection and disconnection of the pull rod joint and the mandrel 1 can be quickly completed by a pushing and pulling method, and the mandrel 1 can be quickly withdrawn from the catheter during the pushing and pulling process. Moreover, the above structure is applicable to mandrels 1 of various specifications. That is to say, when forming catheters of different specifications, the connection between the mandrel 1 and the pull rod can be completed through a single pull rod joint.

[0040] To enable the pull rod joint to be smoothly withdrawn from the mandrel 1, as Figure 6 , Figure 7 , Figure 10 , Figure 11 , Figure 12 and Figure 13 shown, in this embodiment, a receiving groove 334 is formed on the first limiting surface 333, and a limiting protrusion 46 matching the receiving groove 334 protrudes from the second limiting surface 45. With this arrangement, when the limiting portion 33 abuts against the quick-release member 4, the limiting protrusion 46 can be inserted into the receiving groove 334, and the first tapered surface 331 of the limiting portion 33 and the second tapered surface 43 of the quick-release member 4 are quickly coaxially aligned, thereby facilitating the removal of the pull rod joint from the mandrel 1. The quick-release member 4 is provided with an inner hole 41, and the quick-release member 4 is sleeved on the connecting portion of the pulling member 3 through the inner hole 41.

[0041] To further improve the connection efficiency between the pull rod joint and the mandrel 1, as Figures 2-7 shown, in this embodiment, the replacement device further includes a separating member for driving the limiting portion 33 and the quick-release member 4 to automatically separate. In this way, at the beginning of the connection between the pull rod joint and the mandrel 1, the limiting portion 33 and the quick-release member 4 are in a separated state. When the pull rod joint is connected to the mandrel 1, the positioning plug 5 on the mandrel 1 can be directly inserted between the limiting portion 33 and the quick-release member 4, without using an extra structure to separate the limiting portion 33 and the quick-release member 4. This not only simplifies the structure of the replacement device but also ensures the stability of the connection between the pull rod joint and the mandrel 1. Further preferably, the separating member includes a first spring 6, the first spring 6 is sleeved on the connecting portion, and the two legs of the first spring 6 are respectively connected to the limiting portion 33 and the quick-release member 4; in other embodiments, the first spring 6 can also be arranged between the quick-release member 4 and the mandrel pull rod 2, one leg of the first spring 6 is connected to the quick-release member 4, and the other leg of the first spring 6 is connected to the connecting portion of the pulling member 3; in other embodiments, other elastic connecting members can also be used to drive the limiting portion 33 and the quick-release member 4 to separate.

[0042] To make the structure of the replacement device more compact, in this embodiment, as Figure 6 , Figure 7 , Figure 10 , Figure 11 , Figure 12 and Figure 13As shown, an avoidance groove is formed in the accommodating groove 334. One end of the first spring 6 is inserted into the avoidance groove, and the other leg of the spring is connected to the limit protrusion 46 of the quick-release member 4. In this way, the first spring 6 can be arranged between the limiting part 33 and the quick-release member 4, making the structure of the replacement device more compact.

[0043] In this embodiment, for the convenience of assembling the pull rod joint, in this embodiment, as Figures 1-5 shown, a first threaded hole is formed in the avoidance groove of the limiting part 33. The connecting part of the pulling member 3 includes a first connecting part 32 and a second connecting part 31 which are fixedly connected. One end of the first connecting part 32 is fixedly connected to one end of the second connecting part 31, and the other end of the first connecting part 32 is provided with a thread and can be threadedly connected to the threaded hole of the limiting part 33. Further preferably, a second threaded hole is formed at one end of the mandrel pull rod 2. The second connecting part 31 is provided with a thread, and the second connecting part 31 can be inserted into the second threaded hole of the mandrel pull rod 2 and threadedly connected; and the outer diameter of the mandrel pull rod 2 is larger than the outer diameters of both the first connecting part 32 and the second connecting part 31. Such a setting not only facilitates the connection between the mandrel pull rod 2 and the pull rod joint, but also can limit the stroke of the quick-release member 4 through the mandrel pull rod 2.

[0044] In order to make the pull rod joint more compact to adapt to more specifications of conduits, in this embodiment, as Figures 10-13As shown, the outer surface of the limiting portion 33 further includes a first transition surface 332. The first conical surface 331 and the first limiting surface 333 are connected by the first transition surface 332, and the section line of the first transition surface 332 extends axially; the outer surface of the quick-release member 4 includes a second transition surface 44. The second conical surface 43 and the second limiting surface 45 are connected by the second transition surface 44, and the section line of the second transition surface 44 extends axially; the surface of the positioning plug-in 5 close to the axis of the mandrel 1 is a third transition surface 511, and the section line of the third transition surface 511 extends axially; in this way, the positioning plug-in 5 can slide along the first transition surface 332 and the second transition surface 44 during the axial movement, making the movement process of the positioning plug-in 5 more stable. Further preferably, the radius of the first transition surface 332 is the same as the radius of the second transition surface 44, making the structure of the tie rod joint more compact. Further preferably, the axial lengths of the first transition surface 332, the third transition surface 511, and the second transition surface 44 decrease in sequence. In this way, during the process of the positioning plug-in 5 moving from the second conical surface 43 of the quick-release member 4 to the third transition surface 511, the first spring 6 is in a compressed state. During the process of the positioning plug-in 5 moving from the second transition surface 44 of the quick-release member 4 to the first transition surface 332 of the pulling member 3, since the axial length of the second transition surface 44 of the quick-release member 4 is smaller than the axial length of the third transition surface 511, the third transition surface 511 of the positioning plug-in 5 can press against both the second transition surface 44 and the first transition surface 332 at the same time, further enabling the positioning plug-in 5 to stably disengage from the tie rod joint and further increasing the stability of disassembly. Further preferably, as Figure 8 and Figure 9 shown, the positioning plug-in 5 further includes a third limiting surface 513 and an inclined surface 512. The third limiting surface 513 is arranged radially, and the third limiting surface 513 and the inclined surface 512 are connected by the third transition surface 511; after the positioning plug-in 5 is inserted between the limiting portion 33 and the quick-release member 4, the third limiting surface 513 and the first limiting surface 333 are arranged face to face. During the process of pulling out the mandrel 1 from the catheter, the first limiting surface 333 and the third limiting surface 513 are abutted against each other. In this way, the two radially arranged planes can be firmly abutted against each other, preventing the positioning plug-in 5 from disengaging from the joint of the mandrel 1 and ensuring the stability of the process of pulling out the mandrel 1; during the process of removing the tie rod joint from the mandrel 1, the second limiting surface 45 of the quick-release member 4 and the inclined surface 512 of the positioning plug-in 5 are abutted against each other, enabling the positioning plug-in 5 to smoothly move between the quick-release member 4 and the core rod tie rod 2, further improving the stability of removing the tie rod joint from the mandrel 1.

[0045] Further preferably, the positioning plug 5 further includes an arc surface 514, and the arc surface 514 and the third transition surface 511 are connected by the inclined surface 512. When the positioning plug 5 is inserted between the limiting portion 33 and the quick-release member 4, the arc surface 514 can abut against the connection portion between the second transition surface 44 and the second limiting surface 45 of the quick-release member 4. In this way, the arc surface has a large deformation curve. In this way, when the tie rod joint needs to be removed from the mandrel, it is necessary to push the tie rod joint forcefully so that the connection portion between the second transition surface 44 and the second limiting surface 45 can push the positioning plug outward, and then the connection portion between the second transition surface 44 and the second limiting surface 45 can push the inclined surface to move the positioning plug out from between the quick-release member and the limiting portion, so as to ensure the stability of the connection between the tie rod joint and the mandrel.

[0046] In order to make the structure of the mandrel 1 more compact, in this embodiment, a plurality of radially extending limiting holes 13 are provided on the mandrel 1, the positioning plug 5 is inserted into the limiting holes 13 and is slidably connected, and a quick-connection groove 11 is provided on the connection end of the mandrel 1, and the plurality of limiting holes 13 are all communicated with the quick-connection groove 11. With such a setting, the tie rod joint can extend into the mandrel 1 and complete the connection inside the mandrel 1, making the connection tighter. Further, as Figures 1-9 shown, the positioning plug 5 includes a plugging portion 51 and a positioning portion 52. The third limiting surface 513, the third transition surface 511, the inclined surface 512 and the arc surface 514 are all provided on the plugging portion 51. One end of the positioning portion 52 is connected to the side of the plugging portion 51 opposite to the third limiting surface 513. A clamping groove 521 is provided on the positioning portion 52. A positioning piece 54 is sleeved on the positioning portion 52. The retaining ring 53 is installed in the clamping groove 521 of the positioning portion 52. The positioning piece 54 is located between the retaining ring 53 and the plugging portion. A second spring 55 is sleeved on the positioning portion 52. The two ends of the second spring 55 respectively abut against the positioning piece 54 and the plugging portion 51. A plurality of connection holes 12 are also provided on the mandrel 1. The plurality of connection holes 12 and the plurality of limiting holes 13 correspond to each other one by one and are communicated. The positioning piece 54 is fixed in the connection holes 12. Embodiment 2

[0047] As Figure 15 and 16 shown, the difference between this embodiment and Embodiment 1 is that the plugging portion 51 further includes a fourth limiting surface 515, the fourth limiting surface 515 and the inclined surface 512 are connected by the arc surface 514, and the fourth limiting surface 515 is parallel to the second limiting surface 45; when the positioning plug 5 is inserted between the limiting portion 33 and the quick-release member 4, the fourth limiting surface 515 of the plugging portion 51 abuts against the second limiting surface 45 of the quick-release member 4. In this way, through two perpendicular planes, the accidental detachment of the mandrel and the tie rod joint can be effectively avoided, and the stability of the connection between the mandrel and the tie rod joint is further improved.

[0048] In this embodiment, a third spring is further sleeved on the connecting portion 32, and two ends of the third spring respectively abut against the quick-release member and the end face of the mandrel pull rod; thus, when the positioning plug 5 is inserted between the limiting portion 33 and the quick-release member 4, the third spring can push the quick-release member 4, so that the fourth limiting surface 515 of the plugging portion 51 remains in contact with the second limiting surface 45 of the quick-release member 4, and at the same time, the mandrel pull rod can be prevented from moving relative to the mandrel. Further preferably, the force of the third spring is greater than that of the first spring.

[0049] To facilitate the removal of the mandrel pull rod from the mandrel, as Figure 15 and 16 shown, in this embodiment, a sleeve is sleeved on the connecting portion 32, the quick-release member is sleeved on the sleeve, a first retaining ring and a second retaining ring are provided on the sleeve, the first retaining ring is located on the left side of the second retaining ring, the quick-release member is located between the first retaining ring and the second retaining ring, and the quick-release member can slide between the first retaining ring and the second retaining ring; when the positioning plug 5 is inserted between the limiting portion 33 and the quick-release member 4, the end face of the sleeve abuts against the inclined surface 512 of the positioning plug, and two ends of the first spring 6 respectively abut against the sleeve and the connecting portion of the pulling member 3; when the pull rod joint is removed from the mandrel, the mandrel pull rod is pushed to compress the third spring and stretch the first spring. When the end face of the mandrel pull rod abuts against the right end of the sleeve, the mandrel pull rod drives the sleeve to move synchronously. The sleeve pushes the inclined surface 512 of the positioning plug 5, so that the positioning plug 5 moves outward relative to the mandrel. When the sleeve disengages from the inclined surface of the positioning plug, the arc surface of the positioning plug abuts against the connection portion of the second transition surface 44 and the second limiting surface 45 of the quick-release member, thereby completing the sequential unlocking of the pull rod joint and the mandrel. Then, the mandrel pull rod is continuously pushed. Since the arc surface of the positioning plug abuts against the connection portion of the second transition surface 44 and the second limiting surface 45 of the quick-release member, the quick-release member slides on the sleeve. When the quick-release member abuts against the second retaining ring, the mandrel pull rod can drive the quick-release member to move synchronously through the sleeve and the second retaining ring. The quick-release member pushes the positioning plug upward along the arc surface of the positioning plug. When the quick-release member disengages from the arc surface of the positioning plug, the secondary unlocking of the mandrel pull rod and the mandrel is completed. Then, the mandrel pull rod is continuously pushed, so that the connection portion of the second transition surface 44 and the second limiting surface 45 of the quick-release member pushes the positioning plug 5 to move outward relative to the mandrel along the inclined surface 512 of the positioning plug 5 until the positioning plug moves out from between the limiting portion and the quick-release member. With such a setting, the mandrel joint and the mandrel need to be unlocked on both sides before they can be separated, and the pull rod joint is more stably connected to the mandrel and is not easily separated.

[0050] The regional structures of this embodiment are the same as those of Embodiment 1.

[0051] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0052] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A device for quickly replacing a mandrel of a pipe fitting, characterized in that: It includes a drawbar joint and a mandrel drawbar (2), and the drawbar joint is installed at the end of the mandrel drawbar (2); one end of the mandrel (1) is a forming end inserted into the catheter, and the other end of the mandrel (1) is a connection end connected to the replacement device. A plurality of positioning inserts (5) are installed on the connection end, and the plurality of positioning inserts (5) are arranged around the axis of the mandrel (1). The positioning inserts (5) are installed on the mandrel (1) and can slide radially along the mandrel (1); the drawbar joint includes a pulling member (3) and a quick-release member (4). The pulling member (3) includes a limiting portion (33) and a connecting portion. One end of the connecting portion is fixedly connected to the limiting portion (33), and the other end of the connecting portion is fixedly connected to the mandrel drawbar (2). The quick-release member (4) is sleeved on the connecting portion, and the quick-release member (4) is located between the limiting portion (33) and the mandrel drawbar (2). The outer surface of the limiting portion (33) includes a first conical surface (331), a first transition surface (332) parallel to the axis, and a first limiting surface (333) perpendicular to the axis; The outer surface of the quick-release member (4) includes a second conical surface (43), a second transition surface (44) parallel to the axis, and a second limiting surface (45) perpendicular to the axis. The second conical surface (43) and the second limiting surface (45) are connected by the second transition surface (44); A first spring (6) is sleeved on the connecting portion. The two ends of the first spring (6) are respectively connected to the limiting portion (33) and the quick-release member (4), and the first spring (6) can push the limiting portion (33) and the quick-release member (4) to separate; A quick-connection groove (11) is opened on the connection end of the mandrel (1), and a plurality of radially extending limiting holes (13) are opened on the mandrel (1). The plurality of limiting holes (13) are all communicated with the quick-connection groove (11); the positioning insert (5) is inserted into the limiting hole (13), and a second spring (55) is sleeved on the positioning insert (5). One end of the second spring (55) abuts against the positioning insert (5), and the other end of the second spring (55) abuts against the mandrel (1). The second spring (55) can drive the positioning insert (5) to extend into the quick-connection groove (11); The positioning insert (5) further includes an inclined surface (512), a third limiting surface (513), and a third transition surface (511) parallel to the axis. The third limiting surface (513) and the inclined surface (512) are connected by the third transition surface (511); when the positioning insert (5) is inserted between the limiting portion (33) and the quick-release member (4), the third limiting surface (513) abuts against the first limiting surface (333).

2. The quick replacement device for a pipe fitting mandrel according to claim 1, characterized in that: A receiving groove (334) is opened on the first limiting surface (333), and a limiting projection (46) matching the receiving groove (334) protrudes on the second limiting surface (45).

3. A rapid pipe fitting mandrel replacement device according to claim 1, characterized in that: The positioning plug (5) further includes an arc surface (514), and the arc surface (514) and the third transition surface (511) are connected by the inclined surface (512). When the positioning plug (5) is inserted between the limiting portion (33) and the quick-release member (4), the arc surface (514) can abut against the connection portion between the second transition surface (44) and the second limiting surface (45) of the quick-release member (4).

4. A rapid pipe fitting mandrel replacement device according to claim 1, characterized in that: The axial lengths of the first transition surface (332), the third transition surface (511), and the second transition surface (45) decrease in sequence.

5. A rapid replacement device for a pipe fitting mandrel according to claim 1, characterized in that: The radius of the first transition surface (332) is the same as the radius of the second transition surface (45).

6. The quick replacement device for a pipe fitting mandrel according to claim 1, characterized in that: The third limiting surface (513) is perpendicular to the axis.

7. A rapid pipe fitting mandrel replacement device according to claim 1, characterized in that: A positioning piece (54) is sleeved on the positioning plug (5), the positioning piece (54) is fixedly connected to the mandrel (1), a retaining ring (53) is fixed on the positioning plug (5), the retaining ring (53) is located outside the positioning piece (54), and two ends of a second spring (55) respectively abut against the positioning plug (5) and the positioning piece (54).

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