A quick-changing tool for a pipe bending machine core rod and a changing method thereof

Abstract

The present invention discloses a quick-change tooling and replacement method for a mandrel of a pipe bending machine, and belongs to the field of mechanical processing. The tooling includes a mandrel, a core rod, a mandrel connecting rod and a core rod connecting rod; one end of the mandrel connecting rod is threadedly connected to the mandrel, and the other end is provided with a convex block or a groove; one end of the mandrel connecting rod is threadedly connected to the mandrel, and the other end is provided with a groove that matches the convex block of the mandrel connecting rod or a convex block that matches the groove of the mandrel connecting rod; the other end of the mandrel connecting rod and the other end of the mandrel connecting rod are positioned by the convex block and the groove, and the mandrel connecting rod and the mandrel connecting rod are fixedly connected. It can enable a mandrel and a core rod of extremely heavy weight to be quickly aligned, greatly improve the efficiency of replacing the mandrel, and save time and effort. The method adopts the above-mentioned mandrel quick-change tooling, which can quickly replace a mandrel of extremely heavy weight, save replacement time, and improve work efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and more specifically, relates to a quick-changing tool and a method for replacing a core rod of a pipe bending machine. Background Art

[0002] Mechanical processing refers to the process of changing the external dimensions or performance of a workpiece through a mechanical device, among which pipe bending is a type of mechanical processing. The pipe bender is the most commonly used bending equipment for pipe bending. When using a pipe bender to bend pipes, in order to prevent the inner wall of the pipe from deforming and the inner diameter of the pipe from changing, it is usually necessary to add a mandrel to the bent pipe to support the inner wall of the pipe bending radius and prevent it from deforming.

[0003] Since pipes come in different lengths, when the bend is far from the end of the pipe, the mandrel needs to extend a long distance into the pipe. Therefore, the mandrel is usually threaded with a core rod, and the position of the mandrel in the pipe is controlled by controlling the length of the core rod that extends into the pipe. However, when processing large pipes, the required mandrel is extremely large, and the length and diameter of the core rod are also large. In order to prevent the two from deforming when the pipe is bent, the two are usually made of metal with higher quality and hardness, which results in a very large weight. When pipes with different inner diameters need to be processed, the replacement of the mandrel is extremely troublesome.

[0004] In the prior art, when replacing such a heavy mandrel, the mandrel is usually fixed in a certain position, and then the mandrel is moved by a trolley. Then the worker holds the mandrel by hand to align the threaded connection part of the mandrel with the threaded hole of the mandrel, and then the threaded connection is performed after the alignment is accurate. However, due to the heavy weight of the mandrel, it is extremely difficult for the worker to align the mandrel. Once the mandrel and the mandrel deviate when they are pre-aligned, the threaded connection part of the mandrel cannot be screwed into the threaded hole of the mandrel, and a large number of attempts are required. In actual operation, it often takes more than two workers more than half a day to complete the replacement of the mandrel, which is extremely time-consuming and labor-intensive.

[0005] For example, a patent document with Chinese patent application number: CN201320419871.8 and publication date: December 21, 2013 discloses a mandrel assembly for a pipe bending machine, including a bead core and a mandrel, the bead core is in the shape of a spherical table, the mandrel includes a bead core mounting rod and a connecting rod, the front end of the bead core mounting rod is provided with an axial first center hole, the rear end is provided with a second center hole connected to the first center hole, the aperture of the first center hole is smaller than the aperture of the second center hole; a threaded center hole is provided on the rotation center of the bead core, a connecting bolt is installed in the first center hole in a clearance fit, the connecting bolt is connected to the threaded center hole of the bead core, there is a gap between the bead core and the end of the bead core mounting rod to facilitate the axial movement of the connecting bolt, the second center hole is connected to the front end of the connecting rod, the rear end of the connecting rod is provided with a connecting hole, and the central axes of the bead core mounting rod, the connecting rod, the first center hole, and the second center hole are coaxial. The mandrel assembly supports the bending part of the pipe fitting when bending the pipe, so that it is not easy to be flattened and deformed, and the mandrel assembly is easy to replace, reducing the cost.

[0006] Another example is a Chinese patent application number: CN201220592562.6, and a patent document published on June 19, 2013, which discloses a combined pipe bending machine ball pin assembly, including a bead core and a core rod. The bead core is connected to the core rod through a combined connecting piece. The combined connecting piece includes a spherical rod, a connecting rod and a working rod. The working rod is connected to the front end of the core rod through a base hole clearance fit and a threaded connection. The connecting rod is fitted in the middle hole of the working rod, and its rear end is connected and locked with the core rod through a locking bolt. The front end of the connecting rod is locked with the spherical rod through an inner spherical surface, and the spherical rod is assembled and connected to the bead core; the central axes of the spherical rod, the connecting rod, the working rod, the locking bolt and the core rod are located on the same center line. The ball pin assembly of the combined pipe bending machine adopts a combined structure. When the ball pin assembly enters the wear period and needs to be replaced, only the working rod with low processing technology content needs to be replaced, retaining the core rod with high processing cost and not easy to wear, avoiding the entire ball pin assembly from being discarded, which not only saves costs, but also reduces the processing burden of accessories, shortens the overall processing and replacement time, and improves production efficiency.

[0007] The mandrels of the above two types of pipe bending machines are both easy to install. However, the mandrels and core rods of the two are connected by threads. When processing large pipe fittings and extremely large and heavy pipe fittings must be used, the aforementioned difficulties of transportation by crane and manual centering still exist, which is time-consuming and labor-intensive, and cannot solve the aforementioned problem of time-consuming and labor-intensive mandrel replacement. Summary of the invention

[0008] 1. Problems to be solved

[0009] In view of the problem that existing pipe bending machines need to use extremely large mandrels and core rods when processing large pipe fittings, which makes it difficult to align and install the mandrels and the core rods, and the replacement of the mandrels is time-consuming and labor-intensive, the present invention provides a pipe bending machine mandrel quick-change tool, which can quickly align the extremely heavy mandrel and core rod, greatly improve the efficiency of mandrel replacement, and save time and labor.

[0010] The present invention also provides a method for replacing a mandrel of a pipe bending machine. By using the mandrel quick-change tooling, a mandrel with a very heavy weight can be quickly replaced, thus saving replacement time and improving work efficiency.

[0011] 2. Technical solution

[0012] To solve the above problems, the present invention adopts the following technical solutions.

[0013] A quick-change tool for a mandrel of a pipe bending machine comprises a mandrel, a mandrel, a mandrel connecting rod and a mandrel connecting rod; one end of the mandrel connecting rod is threadedly connected to the mandrel, and the other end is provided with a protrusion or a groove; one end of the mandrel connecting rod is threadedly connected to the mandrel, and the other end is provided with a groove that matches the protrusion of the mandrel connecting rod or a protrusion that matches the groove of the mandrel connecting rod; the other end of the mandrel connecting rod and the other end of the mandrel connecting rod are positioned by the protrusion and the groove, and the mandrel connecting rod and the mandrel connecting rod are fixedly connected.

[0014] As a further improvement of the technical solution, it also includes a connecting sleeve; the connecting sleeve includes a connecting rod sleeve and a locking sleeve; the connecting rod sleeve is spliced ​​by two identical semi-cylindrical connecting rod sleeve assemblies, and a cavity is provided in the connecting rod sleeve, and the cavity matches the connection part of the core rod connecting rod and the core rod connecting rod; a thread is provided on the outer wall of the connecting rod sleeve, and a threaded hole matching the thread of the connecting rod sleeve is provided on the locking sleeve along the axial direction.

[0015] As a further improvement of the technical solution, the diameter of the connecting portion between the mandrel connecting rod and the core rod connecting rod is larger than the diameter of the mandrel connecting rod and the core rod connecting rod connected to the connecting portion.

[0016] As a further improvement of the technical solution, at least one pair of mandrel adjusting screw holes are symmetrically provided on the side surface of the mandrel near the mandrel connecting rod along the axis of the mandrel, and the mandrel adjusting screw holes are perpendicular to the axis of the mandrel.

[0017] As a further improvement of the technical solution, at least one pair of core rod adjusting screw holes are symmetrically provided on the side surface of the core rod connecting rod near the core rod along the axis of the core rod connecting rod, and the core rod adjusting screw holes are perpendicular to the axis of the core rod connecting rod.

[0018] As a further improvement of the technical solution, the core rod connecting rod, the core rod connecting rod and the core rod are respectively provided with through holes penetrating their upper and lower end surfaces along their respective axes.

[0019] A method for replacing a core rod of a pipe bending machine, using the above-mentioned core rod quick-changing tooling for a pipe bending machine, comprises the following steps:

[0020] 1. Fix the mandrel, then thread the mandrel connecting rod and the mandrel connecting rod to the mandrel and the mandrel respectively and then lock them;

[0021] Second, move the core rod connecting rod to make the protrusions and grooves of the core rod connecting rod and the core rod connecting rod fit together, and then fix and connect the core rod connecting rod and the core rod connecting rod.

[0022] As a further improvement of the technical solution, in step two, the specific steps for fixedly connecting the core rod connecting rod and the core rod connecting rod are as follows: after the protrusions of the core rod connecting rod and the core rod connecting rod are inserted into the grooves, the two connecting rod sleeve assemblies are controlled to cover the connecting parts of the core rod connecting rod and the core rod connecting rod to form a connecting rod sleeve, and then, the locking sleeve is controlled to be threadedly connected to the connecting rod sleeve along the axial direction of the connecting rod sleeve.

[0023] As a further improvement of the technical solution, the following steps are also included: after the core rod and the core rod connecting rod are threadedly connected, a long rod is first inserted into the axial through holes of the core rod, the core rod connecting rod and the core rod connecting rod in sequence, and then the three are connected.

[0024] As a further improvement of the technical solution, when the core rod and the core rod connecting rod are connected, and the core rod and the core rod connecting rod are connected, screws are screwed into the core rod adjusting screw holes and the core rod adjusting screw holes respectively to tighten the core rod connecting rod and the core rod.

[0025] 3. Beneficial effects

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The invention provides a mandrel quick-change tool for a pipe bending machine. By providing a mandrel connecting rod and a mandrel connecting rod with a protrusion or a groove, the connection between the mandrel and the mandrel is cleverly changed from a threaded connection with high centering requirements to a method of first positioning with a clamping block and then fixing the connection. This allows the connection of a mandrel and a mandrel with a very large weight to be achieved without the need for high-precision pre-centering, thereby greatly improving the efficiency of replacing the mandrel.

[0028] (2) The present invention provides a quick-change tool for a mandrel of a pipe bending machine, wherein the diameter of the connecting portion of the mandrel connecting rod and the core rod connecting rod is larger than the diameter of the mandrel connecting rod and the core rod connecting rod on both sides connected thereto, i.e., a protruding circular step ladder-like structure is formed at the connecting portion, and in combination with a connecting rod sleeve assembly covering the connecting portion and a locking sleeve for locking the connecting rod sleeve assembly into a connecting rod sleeve, the connection between the mandrel connecting rod and the core rod connecting rod is extremely convenient and the connection is stable. In addition, the outer thread of the connecting rod sleeve and the locking sleeve with a threaded hole can correct the coaxiality of the mandrel connecting rod and the core rod connecting rod while being threadedly connected, thereby improving the coaxiality of the two, and thereby indirectly improving the coaxiality of the mandrel and the core rod;

[0029] (3) The invention provides a quick-change tool for a mandrel of a pipe bending machine. When a mandrel and a mandrel connecting rod, or a mandrel and a mandrel connecting rod are threadedly connected, a screw can be screwed into the side of the mandrel and the mandrel connecting rod to support the screw in the threaded hole in the connection. On the one hand, the position of the screw in the threaded hole in the mandrel or the mandrel connecting rod in the radial direction can be adjusted by controlling the length of the screw screwed in, so that the two connected parts are accurately aligned. On the other hand, it plays a role in strengthening the connection.

[0030] (5) The invention provides a quick-change tool for a mandrel of a pipe bending machine, wherein the mandrel connecting rod, the core rod connecting rod and the core rod are respectively provided with through holes penetrating the upper and lower end surfaces thereof along their respective axes. Before installation, a long rod can be inserted into the through hole of the axis, thereby realizing pre-positioning of the mandrel connecting rod, the core rod connecting rod and the core rod, thereby improving installation efficiency and installation accuracy, and saving time for replacing the mandrel;

[0031] (6) A method for replacing a core rod of a tube bending machine according to the present invention adopts the above-mentioned quick-changing tooling for the core rod of a tube bending machine, which can effectively improve the replacement efficiency of heavy core rods and save replacement time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the quick-change tooling;

[0033] Figure 2 This is a partial enlarged view of the front end of the quick-change tooling;

[0034] Figure 3 for Figure 2 A cross-sectional view along the axial direction of the core rod;

[0035] Figure 4 Bit Figure 3 A partial enlarged view of the connection between the center core rod connecting rod and the core rod connecting rod;

[0036] Figure 5 This is a partial enlarged view of the front end of the quick-change tooling without the connecting sleeve;

[0037] Figure 6 It is a structural schematic diagram of a connecting rod sleeve;

[0038] Figure 7 It is a structural schematic diagram of a connecting rod sleeve assembly;

[0039] Figure 8 It is a structural schematic diagram of the mandrel connecting rod;

[0040] Fig. 9 It is a structural schematic diagram of the core rod connecting rod;

[0041] In the figure: 1, core rod; 11, core rod adjusting screw hole; 2, core rod; 3, core rod connecting rod; 4, core rod connecting rod; 41, core rod adjusting screw hole; 5, connecting sleeve; 51, connecting rod sleeve; 511, connecting rod sleeve assembly; 52, locking sleeve; 53, connecting part; 6, center axis hole. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments and drawings.

[0043] Example 1

[0044] A quick-change tool for a tube bending machine core rod is mainly used for replacing a very heavy tube bending machine core rod, solving the problem that when replacing a very heavy tube bending machine core rod, a crane is needed to transport the same heavy core rod, and then the core rod is manually held to pre-center the connection, which is extremely difficult, time-consuming and labor-intensive to operate. Figure 1 and Figure 5 As shown, the quick-change tool mainly includes a mandrel 1, a mandrel 2, a mandrel connecting rod 3, a mandrel connecting rod 4 and a connecting sleeve 5, wherein the mandrel 1 and the mandrel 2 are the main working parts of the mandrel of the pipe bending machine, and the mandrel connecting rod 3, the mandrel connecting rod 4 and the connecting sleeve 5 are important parts for realizing the quick connection and installation of the extremely heavy mandrel 1 and the mandrel 2. The specific structure, connection method and working principle of each component are described in detail below.

[0045] like Figures 2 to 5 As shown, the structure of the mandrel 1 is basically the same as that of the common mandrels for pipe bending machines on the market. Its overall structure is cylindrical, and the front end is the part that extends into the pipe to be bent and contacts the bending part, and a threaded hole extending along the axial direction of the mandrel 1 is provided at the center of the rear end face. The mandrel 2 is a cylindrical long rod structure, and an external thread is provided on the outer side of one end of the mandrel 2. In coordination, an external thread matching the threaded hole of the mandrel 1 is provided on the outer side of one end of the mandrel connecting rod 3, and a threaded hole matching the external thread of the mandrel 2 is provided at the center of the end face of one end of the mandrel connecting rod 4. When the mandrel needs to be replaced, the mandrel connecting rod 3 is first threadedly connected to the mandrel 1 and then locked by a nut, and the mandrel connecting rod 4 is threadedly connected to the mandrel 2 and then locked by a nut, and then the mandrel connecting rod 3 and the mandrel connecting rod 4 are fixedly connected to realize the fixed connection of the mandrel 1 and the mandrel 2.

[0046] However, if the mandrel connecting rod 3 and the mandrel connecting rod 4 are connected by conventional threaded connection, the mandrel 2 will also be very heavy and thus pre-alignment will be difficult. If the mandrel connecting rod 3 and the mandrel connecting rod 4 are not connected by threaded connection, it will be difficult to ensure the coaxiality of the mandrel connecting rod 3 and the mandrel connecting rod 4, thereby affecting the coaxiality of the mandrel 1 and the mandrel 2. In view of this, the present embodiment has specially designed the structures of the other ends of the mandrel connecting rod 3 and the mandrel connecting rod 4 relative to the mandrel 1 and the mandrel 2, respectively, and combined with the locking and fixing of the connecting rod sleeve 5, the two can be connected together ingeniously without high-precision thread pre-alignment, and the coaxiality of the two is also guaranteed.

[0047] Specifically, the end surfaces of the mandrel connecting rod 3 and the mandrel connecting rod 4 at the other ends relative to the mandrel 1 and the mandrel 2 are provided with mating protrusions and grooves. The protrusions or grooves can be provided on any one of the mandrel connecting rod 3 and the mandrel connecting rod 4. It is only necessary to ensure that one of the other end surfaces of the two is provided with a protrusion and the other is provided with a groove to achieve the mating effect. Figure 8 and Fig. 9 As shown, in this embodiment, a projection is provided on the other end surface of the mandrel connecting rod 3, and a groove is provided on the other end surface of the mandrel connecting rod 4, and the projection and the groove match each other in shape and size. When the mandrel connecting rod 3 and the mandrel connecting rod 4 need to be connected, the connection position of the mandrel connecting rod 3 and the mandrel connecting rod 4 can be positioned by simply inserting the projection into the groove, without the need for pre-centering of the threaded connection, which is convenient and quick. Then, the mandrel connecting rod 3 and the mandrel connecting rod 4 can be locked and connected through the connecting sleeve 5.

[0048] like Figure 4 As shown, the connecting sleeve 5 includes a connecting rod sleeve 51 and a locking sleeve 52. The connecting rod sleeve 51 is formed by splicing two identical semi-cylindrical connecting rod sleeve assemblies 511. There is no direct connection between the two connecting rod sleeve assemblies 511, but the two are fixed by the locking sleeve 52 to form the connecting rod sleeve 51. Specifically, a cavity is provided in the connecting rod sleeve 51, which can just accommodate the connecting portion 53 of the core rod connecting rod 3 and the core rod connecting rod 4, and the front and rear ends of the cavity are through holes for accommodating the core rod connecting rod 3 and the core rod connecting rod 4 on both sides of the connecting portion 53.

[0049] It should be noted that in order to allow the connection portion 53 to be placed exactly in the cavity without causing axial movement to cause the core rod connecting rod 3 and the core rod connecting rod 4 to separate, the diameter of the connection portion 53 needs to be larger than the diameter of the core rod connecting rod 3 and the core rod connecting rod 4 connected thereto, and the diameter of the through hole at the front and rear ends of the cavity and the diameter of this part of the core rod connecting rod 3 and the core rod connecting rod 4 connected to the connection portion 53 remain basically the same. This structure can be achieved in a variety of ways, such as slotting the core rod connecting rod 3 and the core rod connecting rod 4 on both sides of the connection portion 53, or keeping the diameter of the core rod connecting rod 3 and the core rod connecting rod 4 on both sides of the connection portion 53 unchanged, so that the diameter of the connection portion 53 is larger than the diameters on both sides. This embodiment adopts the former method, such as Figure 8 and Fig. 9 As shown, the core rod connecting rod 3 and the core rod connecting rod 4 on both sides of the connecting portion 53 are provided with a circle of grooves along the circumferential direction. After the protrusions and grooves of the core rod connecting rod 3 and the core rod connecting rod 4 are matched, a protruding circular step structure is formed at the connecting portion 53. Figure 7 As shown, it is a semi-cylindrical structure, with a semi-cylindrical groove in the middle and a semi-cylindrical groove with a slightly smaller diameter on both sides. When the two connecting rod sleeve assemblies 511 are spliced ​​together, a semi-cylindrical groove is formed. Figure 7 The connecting rod sleeve 51 shown in the figure has a central cavity that matches the connecting part 53. When the two connecting rod sleeve assemblies 511 cover the connecting part 53, the cavity just accommodates the connecting part 53. The step avoidance between the cavity and the front and rear through holes can limit the axial displacement of the connecting part 53 and prevent the core rod connecting rod 3 and the core rod connecting rod 4.

[0050] In addition, the present embodiment further arranges the protrusions and grooves of the mandrel connecting rod 3 and the mandrel connecting rod 4 into a polygonal structure which can limit the rotation of the mandrel connecting rod 3 relative to the mandrel connecting rod 4. In the present embodiment, the protrusions and grooves are in a quadrilateral, thereby preventing the mandrel connecting rod 3 and the mandrel connecting rod 4 from rotating in relative position when the mandrel is working, causing the mandrel 1 and the mandrel 4 to rotate in relative position, thereby affecting the working effect of the mandrel 1.

[0051] like Figure 3 and Figure 6As shown, the locking sleeve 52 is a cylindrical structure, and a threaded hole connecting the two end faces is opened axially on its end face, and the outer side of the connecting rod sleeve 51 is provided with an external thread that matches the threaded hole, and one end of the connecting rod sleeve 51 is provided with a protruding circle of stepped truncated cone. After the two connecting rod sleeve assemblies 511 cover the connecting part 53 and splice to form the connecting rod sleeve 51, the locking sleeve 52 is axially screwed into the connecting rod sleeve 51 from the end without the truncated cone, and locked after hitting the truncated cone, and the two connecting rod sleeve assemblies 511 are fixed together, so that the core rod connecting rod 3 and the core rod connecting rod 4 are fixedly connected. It is worth mentioning that the coaxiality of the core rod connecting rod 3 and the core rod connecting rod 4 is not easy to ensure when they are spliced ​​together. When this locking sleeve 52 is screwed into the connecting rod sleeve 51, it can correct the coaxiality of the core rod connecting rod 3 and the core rod connecting rod 4 while screwing in, thereby indirectly improving the coaxiality of the core rod 1 and the core rod 2.

[0052] When the mandrel 1 is replaced by the quick-change tool, it is only necessary to first thread the mandrel connecting rod 3 and the mandrel connecting rod 4 with the mandrel 1 and the mandrel 2, respectively, and then position the mandrel connecting rod 3 and the mandrel connecting rod 4 through the protrusion and the groove, and then lock them through the connecting sleeve 5. The mandrel connecting rod 3 and the mandrel connecting rod 4 are relatively light in weight and can be manually installed on the mandrel 1 and the mandrel 2, and the centering is relatively simple. When the combination of the extremely heavy mandrel connecting rod 4 and the mandrel 2 is installed together with the combination of the mandrel 1 and the mandrel connecting rod 3, the positioning through the protrusion and the groove is much simpler than the pre-centering of the thread, so a lot of mandrel replacement time can be saved and manpower and material resources can be reduced.

[0053] In order to further improve the accuracy of the installation of the core rod 2, the core rod connecting rod 4 and the core rod connecting rod 3, especially the fitting accuracy of the protrusion and the groove when the core rod connecting rod 4 and the core rod connecting rod 3 are positioned, in this embodiment, the end faces of the core rod connecting rod 3, the core rod connecting rod 4 and the core rod 2 are respectively provided with through holes penetrating the upper and lower end faces along their respective axes. After installation, the through holes of the three are formed as follows Figure 3 The central axis hole 6 shown. Before installation, insert a long rod from the rear end of the core rod 2 into the through holes of the three in turn to achieve pre-positioning among the three, so that the core rod connecting rod 4 can be more accurately threaded with the core rod 2, and the protrusions and grooves of the core rod connecting rod 3 and the core rod connecting rod 4 can also fit more accurately, without excessive position slippage, so that the connecting sleeve 5 can lock the two together, improving installation efficiency and installation accuracy. It should be noted that the diameters of the central axial through holes of the core rod connecting rod 3, the core rod connecting rod 4 and the core rod 2 should be consistent, so that the long rod can pre-position the three accurately enough.

[0054] In addition, if Figure 2 and Figure 3As shown, in this embodiment, at least one pair of core rod adjusting screw holes 41 are symmetrically provided on the side of the core rod connecting rod 4 near the core rod 2 along the axis of the core rod connecting rod 4, and the core rod adjusting screw holes 41 are perpendicular to the axis of the core rod connecting rod 4. Similarly, at least one pair of core rod adjusting screw holes 41 are symmetrically provided on the side of the core rod connecting rod 4 near the core rod 2 along the axis of the core rod connecting rod 4, and the core rod adjusting screw holes 41 are perpendicular to the axis of the core rod connecting rod 4. When the core rod 1 and the core rod connecting rod 3, and the core rod 2 and the core rod connecting rod 4 are threadedly connected, screws can be screwed into the sides of the core rod 1 and the core rod connecting rod 3 and supported against the screws in the threaded holes in the connection. On the one hand, the position of the screws in the threaded holes in the core rod 1 or the core rod connecting rod 3 in the radial direction can be adjusted by controlling the length of the screws screwed in, so that the two connected are accurately aligned, and on the other hand, the connection is strengthened.

[0055] In summary, the quick-change tooling for the mandrel of a pipe bending machine of the present embodiment can quickly align the mandrel and core rod of extremely heavy weight, greatly improve the efficiency of mandrel replacement, and save time and effort.

[0056] Example 2

[0057] A method for replacing a mandrel of a pipe bender, using a mandrel connecting tool of a pipe bender in Example 1, comprises the following steps:

[0058] 1. After fixing the mandrel 1 to be replaced horizontally in a position, screw the threaded end of the mandrel connecting rod 3 into the threaded hole of the mandrel 1 and lock it with a nut. Next, fix the mandrel 2 in a position, insert a long rod into the through hole of the mandrel 2, and then put one end of the mandrel connecting rod 4 to be threaded on the long rod, so that the long rod is inserted into the through hole of the mandrel connecting rod 4, and then control the mandrel connecting rod 4 to be threadedly connected with the mandrel 2 and lock it with a nut. In this step, since the mandrel connecting rod 3 and the mandrel connecting rod 4 are only components used as intermediate transition connections, they are small in size and light in weight, and the mandrel connecting rod 3 and the mandrel connecting rod 4 can be successfully threadedly connected to the mandrel 1 and the mandrel 2 respectively by hand or with simple tools. At the same time, when the core rod 1 and the core rod connecting rod 3 are connected, and the core rod 2 and the core rod connecting rod 4 are connected, screws are screwed into the core rod adjusting screw hole 11 and the core rod adjusting screw hole 41 respectively to tighten the core rod connecting rod 3 and the core rod 2. By controlling the length of the screw screwed in, the position of the screw in the threaded hole in the radial direction of the core rod 1 or the core rod connecting rod 3 can be adjusted, so that the threaded connection is smoother, and it can also play a role in strengthening the connection after tightening.

[0059] Second, after the locking sleeve 52 is put on the core rod connecting rod 4, the core rod 1 and the core rod connecting rod 3 are transferred by the crane, or the core rod 2 and the core rod connecting rod 4 are hoisted, so that the long rod extending from one end of the through hole of the core rod connecting rod 4 is inserted into the through hole of the core rod connecting rod 3, and then the protrusion of the core rod connecting rod 3 is inserted into the groove of the core rod connecting rod 4 along the long rod. Next, the two connecting rod sleeve assemblies 511 cover the connecting part 53 of the core rod connecting rod 3 and the core rod connecting rod 4 to form the connecting rod sleeve 51, and then the locking sleeve 52 is controlled to be screwed into the connecting rod sleeve 51 from the end of the connecting rod sleeve 51 without the circular step along the axial direction of the connecting rod sleeve 51, and the connecting rod sleeve 51 is locked after it abuts against the circular step, so that the core rod connecting rod 3 and the core rod connecting rod 4 are fixedly connected together. In this way, the core rod 1 and the core rod 2 are changed from a threaded connection that requires high pre-alignment accuracy to a snap-in positioning of the bump and the groove. The positioning is convenient and quick, which effectively improves the replacement efficiency of the heavy core rod and saves replacement time. At the same time, screwing the locking sleeve 52 into the connecting rod sleeve 51 can also well ensure the coaxiality of the core rod 1 and the core rod 2, thereby ensuring the working effect of the replaced core rod.

[0060] In summary, a method for replacing a mandrel of a pipe bending machine in this embodiment adopts a mandrel quick-change tool of embodiment 1, which can quickly replace a mandrel with a very heavy weight, save replacement time, and improve work efficiency.

[0061] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A quick-change tool for a mandrel of a pipe bending machine, comprising a mandrel (1) and a core rod (2), characterized in that: It also includes a mandrel connecting rod (3) and a mandrel connecting rod (4); one end of the mandrel connecting rod (3) is threadedly connected to the mandrel (1), and the other end is provided with a protrusion or a groove; one end of the mandrel connecting rod (4) is threadedly connected to the mandrel (2), and the other end is provided with a groove that matches the protrusion of the mandrel connecting rod (3) or a protrusion that matches the groove of the mandrel connecting rod (3); the other end of the mandrel connecting rod (3) and the other end of the mandrel connecting rod (4) are positioned by the protrusion and the groove, and the mandrel connecting rod (3) and the mandrel connecting rod (4) are fixedly connected; the mandrel connecting rod (3), the mandrel connecting rod (4) and the mandrel connecting rod (2) are respectively provided with through holes that penetrate their upper and lower end faces along their respective axes; after the mandrel (1) and the mandrel connecting rod (3) are threadedly connected, a long rod is first inserted into the through holes of the mandrel (2), the mandrel connecting rod (4) and the mandrel connecting rod (3) in sequence, and then the three are connected; It also comprises a connecting sleeve (5); the connecting sleeve (5) comprises a connecting rod sleeve (51) and a locking sleeve (52); the connecting rod sleeve (51) is formed by splicing two identical semi-cylindrical connecting rod sleeve assemblies (511); a cavity is provided in the connecting rod sleeve (51), and the cavity matches the connecting portion (53) of the core rod connecting rod (3) and the core rod connecting rod (4); a thread is provided on the outer wall of the connecting rod sleeve (51); and a threaded hole matching the thread of the connecting rod sleeve (51) is provided on the locking sleeve (52) along the axial direction; The diameter of the connecting portion (53) between the mandrel connecting rod (3) and the core rod connecting rod (4) is larger than the diameter of the mandrel connecting rod (3) and the core rod connecting rod (4) connected to the connecting portion (53); At least one pair of mandrel adjusting screw holes (11) are symmetrically provided on the side surface of the mandrel (1) near the mandrel connecting rod (3) along the axis of the mandrel (1), and the mandrel adjusting screw holes (11) are perpendicular to the axis of the mandrel (1); At least one pair of core rod adjustment screw holes (41) are symmetrically provided on the side surface of the core rod connecting rod (4) near the core rod (2) along the axis of the core rod connecting rod (4), and the core rod adjustment screw holes (41) are perpendicular to the axis of the core rod connecting rod (4).

2. A method for replacing a mandrel of a tube bending machine, using a quick-changing tool for a mandrel of a tube bending machine according to claim 1, comprising the following steps: First, fix the mandrel (1), then threadably connect the mandrel connecting rod (3) and the mandrel connecting rod (4) to the mandrel (1) and the mandrel (2) respectively, and then tighten them; Second, the core rod connecting rod (4) is moved to make the protrusions and grooves of the core rod connecting rod (4) and the core rod connecting rod (3) fit together, and then the core rod connecting rod (4) and the core rod connecting rod (3) are fixedly connected.

3. A method for replacing a mandrel of a pipe bender according to claim 2, characterized in that: In the second step, the specific steps of fixedly connecting the core rod connecting rod (4) and the core rod connecting rod (3) are as follows: after the protrusions of the core rod connecting rod (4) and the core rod connecting rod (3) are inserted into the grooves, the two connecting rod sleeve assemblies (511) are controlled to cover the connecting portion (53) of the core rod connecting rod (4) and the core rod connecting rod (3) to form a connecting rod sleeve (51), and then the locking sleeve (52) is controlled to be threadedly connected to the connecting rod sleeve (51) along the axial direction of the connecting rod sleeve (51).

4. A method for replacing a mandrel of a pipe bender according to claim 2 or 3, characterized in that: The step one also includes the following steps: after the core rod (1) and the core rod connecting rod (3) are threadedly connected, a long rod is first inserted into the through holes of the core rod (2), the core rod connecting rod (4) and the core rod connecting rod (3) in sequence, and then the three are connected.

5. A method for replacing a mandrel of a pipe bender according to claim 2 or 3, characterized in that: In the step 1, when the core rod (1) and the core rod connecting rod (3) are connected, and the core rod (2) and the core rod connecting rod (4) are connected, screws are screwed into the core rod adjusting screw hole (11) and the core rod adjusting screw hole (41) respectively to tighten the core rod connecting rod (3) and the core rod (2).

Images