Forming method of blank plate with dovetail groove and forming method of rectangular pyramid tubular lamp pole

Abstract

The invention discloses a method for forming a blank plate with a dovetail groove, which is suitable for forming the dovetail groove after a rectangular groove is formed on a straight steel plate through rolling, and comprises the following steps of: firstly forming the left groove wall of the dovetail groove by utilizing at least one left groove wall forming roller group which is obliquely arranged leftwards relative to the central vertical plane of the rectangular groove, and then forming the dovetail groove by utilizing a right groove wall forming roller group which is obliquely arranged leftwards relative to the central vertical plane of the rectangular groove; forming the right side groove wall of the dovetail groove by using at least one group of right groove wall forming roller group which is obliquely arranged rightwards relative to the central vertical plane of the rectangular groove, and leveling and straightening the groove bottom and two wings of the dovetail groove by using a group of leveling and straightening roller group between any two adjacent rolling passes for forming the left side groove wall or the right side groove wall; the leveling and straightening roller sets are power roller sets, and then the plane part of the blank plate with the dovetail groove is leveled and straightened through at least one shape correcting roller set. The forming efficiency of the dovetail groove can be improved, and the forming quality of the dovetail groove is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of lamp post processing, and particularly relates to a forming method for a quadrangular pyramid-shaped lamp post with a dovetail groove. Background Art

[0002] Existing lamp posts are basically hollow tubes with a substantially uniform wall thickness. Lamp posts include those with exactly the same cross-sectional shape and size, as well as tapered lamp posts with the same cross-sectional shape but whose size varies uniformly from one end to the other. There are also combined lamp posts composed of multiple sections of lamp posts. Such combined lamp posts are formed by combining at least two sections of lamp posts. Each section of the lamp post has a cross-section with the same shape, but the cross-sectional shapes of the different sections of the lamp post are not the same or the cross-sectional sizes are not gradually changing.

[0003] To increase the strength of the lamp post or form decorative lines, sometimes grooves are machined along the axial direction of the lamp post. For example, V-shaped grooves or rectangular grooves can be directly formed by stamping or bending. To reliably install other functional components on the lamp post, some lamp posts are designed with dovetail grooves generally arranged along their axial direction. Moreover, for lamp posts at intersections, when it is necessary to indicate road information in the four directions of east, west, south, and north, a quadrangular lamp post with dovetail grooves on all four sides is required to install road signs or other loads on the four sides of the lamp post. Due to the limitation of its shape, the dovetail groove cannot be directly formed by stamping or bending. If a dovetail groove is machined on a lamp post with exactly the same cross-sectional shape and size, it can be processed by drawing, that is, heating a round tube or a square tube and then drawing it to form an installation groove in the shape of a dovetail groove. However, when this processing method is used for processing thicker pipes, cracks are likely to appear inside the dovetail groove, and since the end of the pipe needs to be clamped and pulled during drawing, the end of the drawn pipe will be severely deformed. In the further processing of the pipe, the severely deformed part needs to be cut off, reducing the material utilization rate. Summary of the Invention

[0004] The present invention provides a forming method for a blank plate with a dovetail groove, which can ensure the forming quality of the dovetail groove on the blank plate; on this basis, the present invention also provides a forming method for a quadrangular pyramid-shaped lamp post with a dovetail groove, which jointly solves the technical problem of forming a dovetail groove on a tapered lamp post.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] The forming method of the blank plate with dovetail grooves is applicable to roll a rectangular groove on a flat steel plate and then form the dovetail grooves. The forming method of the blank plate is as follows: at least one set of left groove wall forming roll sets which are inclined leftward relative to the central vertical plane of the rectangular groove are used to form the left groove wall of the dovetail groove first, and then at least one set of right groove wall forming roll sets which are inclined rightward relative to the central vertical plane of the rectangular groove are used to form the right groove wall of the dovetail groove. Between any two adjacent rolling passes for forming the left or right groove wall, there is a set of leveling and straightening roll sets to level and straighten the bottom and two wings of the dovetail groove. All the leveling and straightening roll sets are power roll sets, and then at least one set of shaping roll sets is used to level and straighten the flat part of the blank plate with dovetail grooves.

[0007] In an embodiment of the present invention, both the left groove wall forming roll sets and the right groove wall forming roll sets include a first forming roll and a second forming roll. The cross section of the first forming roll has an angle α with the vertical plane, and the angle between the cross section of the second forming roll and the vertical plane is the same as that between the cross section of the first forming roll and the vertical plane.

[0008] In an embodiment of the present invention, when there are at least two sets of left groove wall forming roll sets, along the advancing direction of the blank plate, the angles α of all the left groove wall forming roll sets are arranged at intervals from small to large. When there are at least two sets of right groove wall forming roll sets, along the advancing direction of the blank plate, the angles α of all the right groove wall forming roll sets are arranged at intervals from small to large.

[0009] In an embodiment of the present invention, the rectangular groove is processed and formed by at least one set of rectangular groove forming roll sets. The rectangular groove forming roll sets include a left side forming roll set and a right side forming roll set. Both the left side forming roll set and the right side forming roll set include a third forming roll and a fourth forming roll. The third forming roll is provided with an annular convex ring, and the fourth forming roll has an annular groove adapted to the rectangular groove. Let the width of the annular convex ring be d1, the groove width of the annular groove be d2, and the thickness of the blank plate be d3, then (d2 - 2d3) / 2 < d1 < d2 - 2d3.

[0010] In an embodiment of the present invention, before and after processing the rectangular groove on the blank plate, a leveling roll set is used to level and straighten the flat part of the blank plate.

[0011] In an embodiment of the present invention, after the blank plate with dovetail grooves is processed, a cutting machine is used to cut the blank plate with dovetail grooves according to a predetermined length.

[0012] The processing method of a four-sided pyramid-shaped lamp pole with dovetail grooves. The four sides of the four-sided pyramid-shaped lamp pole are all provided with dovetail grooves. The processing method is as follows: first, the trapezoidal blank plates of each side are formed by using the aforementioned forming method of the blank plate with dovetail grooves, then the trapezoidal blank plates are spot-welded and assembled into a four-sided pyramid shape, and finally, full welding is performed along the corner ridges to form.

[0013] In an embodiment of the present invention, chamfered transition portions are provided at the corners of the quadrangular pyramid-shaped lamp post. After forming the trapezoidal blank plates for each side, the edges of some trapezoidal blank plates are bent according to the size of the rounded corners first, and then all the trapezoidal blank plates are spot-welded and assembled into a quadrangular pyramid shape, and finally full welding is performed along the corner ridges to form the shape.

[0014] In an embodiment of the present invention, each side of the quadrangular pyramid-shaped lamp post has a dovetail groove. When forming the trapezoidal blank plate, two parallel dovetail grooves are machined on the blank plate first, and then symmetric cutting is performed obliquely between the two dovetail grooves to form two trapezoidal blank plates each having a dovetail groove.

[0015] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0016] The present invention uses a roll forming method to process the dovetail groove. First, a rectangular groove is roll formed on a flat steel plate, and then the left groove wall forming roll group and the right groove wall forming roll group are used to roll the left groove wall and the right groove wall of the rectangular groove respectively to form a semi-finished product with a dovetail groove. Then the semi-finished products are surrounded and spliced into a lamp post, and finally full welding is performed along the corner ridges to form the shape. Selecting to weld and form here can conveniently grind the weld seam and improve the appearance quality. Compared with the prior art that uses a drawing forming method to process the dovetail groove on the lamp post, the processing method of the present invention can avoid cracks in the dovetail groove during the processing process, ensure the forming quality of the dovetail groove, and improve the material utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 Schematic diagram of the device corresponding to the forming method of the blank plate with a dovetail groove in the present invention;

[0019] Figure 2 Schematic diagram of the flattening roll group in the present invention;

[0020] Figure 3 Schematic diagram of the left forming roll group in the rectangular groove forming roll group in the present invention;

[0021] Figure 4 Schematic diagram of the right forming roll group in the rectangular groove forming roll group in the present invention;

[0022] Figure 5 Schematic diagram of the left groove wall forming roll group in the present invention;

[0023] Figure 6 Schematic diagram of the right groove wall forming roller set in the present invention;

[0024] Figure 7 Schematic diagram of the straightening roller set in the present invention;

[0025] Figure 8 Schematic diagram of the processing method of the square pyramid tubular lamp post with dovetail grooves in the present invention;

[0026] Figure 9 Schematic diagram of the square pyramid tubular lamp post with chamfered transition parts at the corners in the present invention;

[0027] Figure 10 Schematic diagram of forming two dovetail grooves on the same blank plate and processing the square pyramid tubular lamp post using this blank plate in the present invention;

[0028] Figure 11 Schematic diagram of the dovetail groove in the present invention.

[0029] Icon: 1 - leveling machine, 11 - leveling roller set, 2 - rectangular groove cold bending forming machine, 21 - left forming roller set, 22 - right forming roller set, 23 - annular convex ring, 24 - annular groove, 3 - dovetail groove forming roller set, 31 - left groove wall forming roller set, 32 - right groove wall forming roller set, 311 - first forming roller, 312 - second forming roller, 4 - leveling and straightening roller set, 5 - straightening roller set, 61 - first cutting machine, 62 - second cutting machine, 7 - unwinding rack, 8 - dovetail groove, 81 - groove bottom flat plate, 82 - S-shaped groove wall, 83 - flank flat plate. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0032] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0033] In the description of the present invention, it should be noted that if terms such as "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use, 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.

[0034] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, if terms such as "set", "installed", "configured", "connected" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. 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.

[0035] A method for forming a blank plate with a dovetail groove is applicable to roll-forming a rectangular groove on a flat steel plate and then forming the dovetail groove 8. The method for forming a blank plate with a dovetail groove of the present invention is as follows: Roll-form a rectangular groove on the flat steel plate, and use at least one set of left groove wall forming roller sets 31 that are inclined to the left with respect to the central vertical plane of the rectangular groove to first form the left groove wall of the dovetail groove 8, and then use at least one set of right groove wall forming roller sets 32 that are inclined to the right with respect to the central vertical plane of the rectangular groove to form the right groove wall of the dovetail groove 8. Between two adjacent rolling passes for forming the left or right groove wall, there is a set of leveling and straightening roller sets 4 to level and straighten the bottom and two wings of the dovetail groove 8, and the leveling and straightening roller sets are all power roller sets, that is, use the leveling and straightening roller sets 4 to provide power for the continuous advancement of the blank plate, and then use at least one set of shaping roller sets to level and straighten the flat part of the blank plate with the dovetail groove 8.

[0036] Among them, the step of roll-forming a rectangular groove on the flat steel plate is prior art, usually: First, unroll the steel coil to form a blank plate, then use the leveling roller set 11 to level and straighten the blank plate, and then according to the depth of the rectangular groove, use at least one set of rectangular groove forming roller sets to form a blank plate with a rectangular groove. The upper and lower rollers of the rectangular groove forming roller sets can move relative to each other, and a first cutting machine is arranged between the feeding rack and the leveling roller set.

[0037] The following embodiment solutions are elaborated in detail based on the above solutions.

[0038] Embodiment

[0039] Please refer to Figures 1 - 11, this embodiment provides a method for forming a blank plate with a dovetail groove, which is applicable to roll-forming a rectangular groove on a flat steel plate and then forming the dovetail groove 8. The method for forming the blank plate is as follows:

[0040] S1. Level and straighten the blank plate. The blank plate can be a steel coil of appropriate size. After uncoiling the end of the steel coil on the coil rack 7, it is fed into the leveling machine 1. The multi-group leveling roller sets 11 included in the leveling machine 1 as shown in Figure 2 are used to level and straighten the steel plate. In this embodiment, the steel coil is a Q235 steel coil with a yield strength of 235 MPa and a thickness of 4 mm. It should be noted that a first cutting machine 61 is arranged between the coil rack and the leveling roller set to cut the steel plate. Since the strip steel released from the steel coil is continuous, when the number and / or size parameters of the dovetail grooves are adjusted, the steel plate needs to be cut, then the equipment is adjusted, and finally production starts again.

[0041] S2. Use the rectangular groove cold bending forming machine 2 to process a rectangular groove on the steel plate. The rectangular groove cold bending forming machine 2 includes multiple groups of rectangular groove forming roller sets, as shown in Figure 3 and Figure 4 . Through multiple passes of rolling, a rectangular groove with designed dimensions is processed on the blank plate. It should be noted that the rectangular groove is formed by multiple passes of rolling. Each pass includes a left-side forming roller set 21 and a right-side forming roller set 22. Both the left-side forming roller set 21 and the right-side forming roller set 22 include a third forming roller and a fourth forming roller. The third forming roller is provided with an annular convex ring 23, and the fourth forming roller has an annular groove 24 adapted to the rectangular groove. Let the width of the annular convex ring be d1, the groove width of the annular groove be d2, and the thickness of the blank plate be d3. Then (d2 - 2d3) / 2 < d1 < d2 - 2d3. The roller structures of the left-side forming roller set 21 and the right-side forming roller set 22 are the same, only the position of the annular convex ring 23 is different. The annular convex ring 23 of the left-side forming roller set 21 is located on the left side of the annular groove 24, as shown in Figure 3 , and the annular convex ring 23 of the right groove wall forming roller set 22 is located on the right side of the annular groove 24, as shown in Figure 4 .

[0042] For example, in a rolling pass, the steel plate after leveling and straightening in step S1 first passes through the left forming roll group 21 for rolling to form the left side of the rectangular groove, then passes through the left forming roll group 22 for rolling to form a rectangular groove with a set groove width. Subsequently, after a set number of rolling passes, the groove depth increases with the increase in the number of passes, and finally a rectangular groove with a set groove depth and groove width is formed. Since the groove depth of the rectangular groove targeted by this forming method reaches 40 mm and the groove depth is relatively large, therefore, in each pass of forming the rectangular groove, the left half of the groove is first rolled to deepen the left half of the groove, and then the right half of the groove is rolled to deepen the right half of the groove, rather than using a forming method of directly rolling the bottom of the groove and stretching and forming the two side walls of the groove at the same time. Because the groove depth of the rectangular groove is relatively large, if the bottom of the groove is directly rolled and the two side walls of the groove are stretched and formed at the same time, during the rolling process, the plastic deformation of the two side walls of the groove will cause the metal at the bottom of the groove to flow to both sides respectively, forming a left - right pulling force on the bottom of the groove, resulting in tearing of the bottom of the rectangular groove. Therefore, this forming method adopts a single - side rolling forming method. For example, when rolling the left side wall of the groove, the bottom of the groove, the right side wall and the right wing plate serve as a whole to provide sufficient metal compensation for the deformation of the left side wall of the groove. The same is true for the forming of the right side wall, so as to ensure the forming quality of the rectangular groove.

[0043] S3. On the basis of the rectangular groove, the left groove - wall forming roll group 31 and the right groove - wall forming roll group 32 are used to process the two side walls of the groove respectively, so that the rectangular groove becomes a dovetail groove 8. Specifically, taking the central vertical plane of the rectangular groove as the reference plane, at least one group of left groove - wall forming roll groups 31 inclined to the left relative to the reference plane, as Figure 5 shown, first roll - press and process the left side wall of the rectangular groove, and then use at least one group of right groove - wall forming roll groups 32 inclined to the right relative to the central vertical plane of the rectangular groove, as Figure 6 shown, to process the right side wall of the rectangular groove to form the left and right side walls of the dovetail groove 8. It should be noted that when changing from a rectangular groove to a dovetail groove 8, the left and right side walls of the groove need to be inclined inward at a certain angle. Therefore, the blank plate with a rectangular groove can be rolled one pass or multiple passes according to actual needs, and finally the dovetail groove 8 is formed. When multiple passes are required, in each pass, one group of left groove - wall forming roll group 31 and one group of right groove - wall forming roll group 32 are used to roll - press the left and right side walls of the groove respectively. In each pass of rolling, the left and right side walls of the groove are inclined inward at a preset angle.

[0044] In step S3, both the left groove - wall forming roll group 31 and the right groove - wall forming roll group 32 include a first forming roll 311 and a second forming roll 312. The cross - section of the first forming roll 311 has an included angle α with the reference plane, and the included angle between the cross - section of the second forming roll 312 and the reference plane is the same as the included angle between the cross - section of the first forming roll 311 and the reference plane, as Figure 5 and Figure 6As shown in the figure. When multiple rolling passes are required, the value of the angle α for each rolling pass is set according to the requirements of each rolling pass, and along the advancing direction of the blank plate, the angles α of all the left groove wall forming roller groups 31 and all the right groove wall forming roller groups 32 are arranged at intervals from small to large. It should be noted that the angle α between the left groove wall forming roller group 31 and the right groove wall forming roller group 32 corresponding to the last rolling pass is the angle between the left and right side walls of the dovetail groove 8 relative to the vertical plane. The upper forming rollers in the left groove wall forming roller group 31 and the right groove wall forming roller group 32 should not contact the upper arc of the dovetail groove 8 on the opposite side to avoid the forming rollers from wearing the workpiece.

[0045] In a production example of the present invention, after the rectangular groove wall is rolled 3 times by the left groove wall forming roller group 31 and the right groove wall forming roller group 32, the angles of the groove wall after each rolling are 7°, 14°, and 20° respectively. After the rectangular groove undergoes 3 changes in the groove wall angle, it finally becomes a dovetail groove, and the final angle of the dovetail groove side wall is 20°.

[0046] In step S3, since the bottom and the two wings of the dovetail groove 8 will be deformed to a certain extent after the blank plate passes through each rolling pass, in order to ensure the accuracy of the final forming size of the dovetail groove 8, between any two adjacent rolling passes for processing the left or right groove wall, there is a set of leveling and straightening roller group 4 to level and straighten the bottom and the two wings of the dovetail groove 8 to ensure the forming quality. At the same time, the leveling and straightening roller group 4 is used to provide power for the continuous advancement of the blank plate, that is, the leveling and straightening roller groups are all power roller groups, as Figure 1 shown. The forming roller structure of the leveling and straightening roller group 4 is similar to that of the forming roller of the rectangular groove cold bending forming machine 2. The difference between the two is that for leveling and straightening the bottom of the dovetail groove 8, the forming roller of the leveling and straightening roller group 4 only rolls the bottom plane and does not roll the left and right side groove walls. The leveling and straightening roller group 4 is the same as the shaping roller group 5, as Figure 7 shown. During the rolling process of the rectangular groove becoming the dovetail groove 8, because between any two adjacent rolling passes for processing the groove wall, there is a set of leveling and straightening roller group 4 to level and straighten the bottom and the two wings of the dovetail groove 8, the processing method of the present invention can process relatively thick blank parts, and the lamp post formed by using this blank part can have higher strength and load-bearing capacity.

[0047] In step S3 of this embodiment, assuming that the dovetail groove 8 is formed after 3 angle changes, there are 3 sets of left groove wall forming roller groups 31 and right groove wall forming roller groups 32 respectively, and 5 sets of leveling and straightening roller groups 4, as Figure 1As shown in the figure, the working process of the blank plate forming device with a dovetail groove 8 in this embodiment is as follows: The raw material steel plate first enters the leveling machine 1, and the leveling roller set 11 is used to level and straighten the steel plate. Then the steel plate enters the rectangular groove cold bending forming machine 2, and after being rolled through at least one pass, a rectangular groove is formed on the steel plate to form a blank plate with a rectangular groove. Then, under the push of the rectangular groove cold bending forming machine 2, the two side walls of the rectangular groove pass through the left groove wall forming roller set 31 of the first pass, the first leveling and straightening roller set 4, and the right groove wall forming roller set 32 of the first pass in sequence, and then enter the second set of leveling and straightening roller set 4. After that, it passes through the left groove wall forming roller set 31 of the second pass, the third leveling and straightening roller set 4, and the right groove wall forming roller set 32 of the second pass, and then enters the fourth set of leveling and straightening roller set 4. After that, it passes through the left groove wall forming roller set 31 of the third pass, the fifth leveling and straightening roller set 4, and the right groove wall forming roller set 32 of the third pass, and finally enters the shaping roller set, and the shaping roller set also adopts a power roller set. Since both the left groove wall forming roller set 31 and the right groove wall forming roller set 32 are non-powered rollers, the rectangular groove cold bending forming machine 2, the leveling and straightening roller set 4, and the shaping roller set before and after the left groove wall forming roller set 31 and the right groove wall forming roller set 32 provide sufficient power for the blank plate, pulling forward and pushing backward, so that the blank plate has enough power to pass through the left groove wall forming roller set 31 and the right groove wall forming roller set 32 and is rolled into shape.

[0048] It should be noted that since the depth of the rectangular groove targeted by this forming method reaches 40 mm and the groove depth is relatively large, in each pass of dovetail groove forming in this forming method, a processing method of first rolling one side groove wall and then rolling the other side groove wall is adopted, rather than a forming method of simultaneously rolling the two side walls of the dovetail groove 8. Because in the method of simultaneously rolling the two side walls to form the dovetail groove 8, during the rolling process, the two side walls bend and deform, causing the metal at the bottom of the groove to flow to both sides respectively, forming a left-right pulling force on the bottom of the groove, resulting in tearing of the bottom of the dovetail groove 8. Therefore, this forming method adopts a single-sided rolling forming method. For example, when rolling the left side groove wall, the bottom of the groove, the right side groove wall, and the right side wing plate serve as a whole to provide sufficient metal compensation for the deformation of the left side groove wall. The same is true for the formation of the right side groove wall, so as to ensure the forming quality of the dovetail groove 8.

[0049] S4. After the dovetail groove 8 is formed, at least one set of shaping roller sets 5 is used to level and straighten the flat part of the blank plate with the dovetail groove 8, and further level and straighten the bottom and two wings of the dovetail groove 8 to obtain a blank plate with a dovetail groove 8. The shaping roller set 5 is the same as the leveling and straightening roller set 4.

[0050] S5. After the blank plate with a dovetail groove 8 is processed, the second cutting machine 62 is used to cut the blank plate with a dovetail groove 8 to a predetermined length. Moreover, the second cutting machine 62 can also be used to cut off workpieces during the trial production process for measurement, so as to finely adjust the positions of the respective forming rollers.

[0051] It should be noted that the principle of forming the dovetail groove 8 side walls by the left side wall forming roller set 31 and the right side wall forming roller set 32 in step S3 is as follows: As Figure 9 shown, assume that the dovetail groove 8 includes a groove bottom flat plate 81, two S-shaped side walls 82, and two flank flat plates 83. The two S-shaped side walls 82 are respectively located on both sides of the groove bottom flat plate 81. One S-shaped side wall 82 matches one flank flat plate 83. The bottom arc part of the S-shaped side wall 82 is connected to the groove bottom flat plate 81, and the top arc part of the S-shaped side wall 82 is connected to the flank flat plate 83. Regarding the specific structures of the first forming roller 311 and the second forming roller 312, as Figure 4 and Figure 5 shown, the working surface of the first forming roller 311 is an S-shaped curved surface adapted to the shape of the S-shaped side wall 82, and the working surface of the second forming roller 312 is a convex curved surface adapted to the shape of the top arc part of the S-shaped side wall 82. When the rectangular groove passes through the left side wall forming roller set 31 or the right side wall forming roller set 32, the first forming roller 311 is inside the groove and acts on the inner wall of the S-shaped side wall 82, and the second forming roller 312 is outside the groove and acts on the outer wall of the top arc part of the S-shaped side wall 82. The first forming roller 311 and the second forming roller 312 are used to forcibly change the vertical side wall into an inclined one. Moreover, both the first forming roller 311 and the second forming roller 312 are non-powered rollers to reduce the resistance when rolling the blank plate. It should be noted that the positions of the first forming roller 311 and the second forming roller 312 can be interchanged, that is, the first forming roller 311 is outside the groove and acts on the outer wall of the S-shaped side wall 82, and the second forming roller 312 is inside the groove and acts on the inner wall of the top arc part of the S-shaped side wall 82.

[0052] It should be noted that this forming method can also produce lamp poles with high strength grades, such as Q355 or Q460, etc. It is basically impossible to process dovetail grooves by the existing cold drawing technology.

[0053] This embodiment also provides a processing method for a square pyramid tubular lamp pole with dovetail grooves 8. The four sides of the square pyramid tubular lamp pole are all provided with dovetail grooves 8. The processing method is as follows: First, use the aforementioned blank plate forming method with dovetail grooves to process the blank plates for each side of the lamp pole, then cut the blank plates into trapezoidal blank plates, and then spot-weld and assemble the trapezoidal blank plates into a square pyramid tube shape, and finally perform full welding along the corner convex ribs to form a square pyramid tubular lamp pole. The cross-sectional shape of the lamp pole is as Figure 7 shown. The square pyramid tubular lamp pole refers to a hollow lamp pole with an outer shape approximately like a square frustum and the pipe diameter gradually changing from small to large along the length direction of the lamp pole.

[0054] When the corner of the square pyramid-shaped lamp post has a chamfered transition part, the processing method of the square pyramid-shaped lamp post with a dovetail groove 8 is as follows: First, adopt the above-mentioned blank forming method with a dovetail groove 8 to process the blanks for each side of the lamp post. Then, bend the edges of some blanks according to the size of the rounded corners. Next, cut all the blanks into trapezoidal blanks. Then, spot-weld and assemble all the trapezoidal blanks into a square pyramid shape. Finally, perform full welding along the corner ridges to form the lamp post. The cross-sectional shape of the lamp post is as shown in Figure 8 shown. The bending process belongs to the prior art and will not be elaborated here.

[0055] When each side of the square pyramid-shaped lamp post has a dovetail groove 8, the processing method of the square pyramid-shaped lamp post with a dovetail groove 8 can also adopt the method of forming two dovetail grooves 8 on the same blank. The specific method is as follows: First, according to the number of dovetail grooves 8, add the left groove wall forming roller group 31 and the right groove wall forming roller group 32. In each rolling pass, one dovetail groove 8 is formed by a series of left groove wall forming roller group 31 and right groove wall forming roller group 32, and the other dovetail groove 8 is formed by another series of left groove wall forming roller group 31 and right groove wall forming roller group 32. At the same time, the rollers of the rectangular groove cold bending forming machine 2, the leveling and straightening roller group 4 and the straightening rollers are all synchronously replaced to adapt to the structure of two dovetail grooves 8. After the equipment is adjusted completely, adopt the above-mentioned blank forming method with a dovetail groove 8. First, process two parallel dovetail grooves 8 on the blank. Then, perform diagonal symmetric cutting between the two dovetail grooves 8 to form two trapezoidal blanks each with a dovetail groove 8. Then, spot-weld and assemble all the trapezoidal blanks into a square pyramid shape. Finally, perform full welding along the corner ridges to form the lamp post. The cross-sectional shape of the lamp post is as shown in Figure 10 shown. It should be noted that in each rolling pass for forming the two dovetail grooves 8, first roll and process one dovetail groove 8, and then roll and process the other dovetail groove 8. In this way, the processing efficiency can be improved.

[0056] The present invention adopts a roll forming method to process the blank with a dovetail groove 8. First, roll a rectangular groove on a flat steel plate, and then use the left groove wall forming roller group 31 and the right groove wall forming roller group 32 to roll the left groove wall and the right groove wall of the rectangular groove respectively to form a semi-finished product with a dovetail groove 8. Then, enclose and splice the semi-finished products into a lamp post. Finally, perform full welding along the corner ridges to form the lamp post. Compared with the prior art that uses a drawing forming method to process the dovetail groove 8 on the lamp post, the processing method of the present invention can avoid cracks in the dovetail groove 8 during the processing, improve the forming efficiency of the dovetail groove 8, and ensure the forming quality of the dovetail groove 8.

[0057] If the structure of three or more dovetail grooves is designed on a certain side of the square pyramid-shaped lamp post, it can be formed by splicing two or more blanks with dovetail grooves.

[0058] It should be noted that the dovetail groove structures processed by the method of the present invention have the same cross-sectional dimensions on the blank plate, that is, except for inevitable manufacturing errors, there will be no dimensional changes in the dovetail grooves along the axial direction of the blank plate, so as to facilitate the cooperation with the mounting parts of unified dimensions, thereby using the mounting parts to apply additional loads on the lamp post.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for forming a blank plate with a dovetail groove, which is applicable to roll-forming a rectangular groove on a flat steel plate and then forming a dovetail groove, is characterized in that: Using at least one set of left groove wall forming roller sets inclined leftward with respect to the central vertical plane of the rectangular groove to first form the left groove wall of the dovetail groove, and then using at least one set of right groove wall forming roller sets inclined rightward with respect to the central vertical plane of the rectangular groove to form the right groove wall of the dovetail groove. Between any two adjacent rolling passes for forming the left or right groove wall, there is a set of leveling and straightening roller sets to level and straighten the bottom and two wings of the dovetail groove. All of the leveling and straightening roller sets are power roller sets. Then, using at least one set of shaping roller sets to level and straighten the planar part of the blank with the dovetail groove.

2. The method for forming a blank plate with a dovetail groove according to claim 1, characterized in that: Both the left groove wall forming roller set and the right groove wall forming roller set include a first forming roller and a second forming roller. The cross-section of the first forming roller has an angle α with the vertical plane, and the angle between the cross-section of the second forming roller and the vertical plane is the same as the angle between the cross-section of the first forming roller and the vertical plane.

3. The method for forming a blank plate with a dovetail groove according to claim 2, characterized in that: When there are at least two sets of left groove wall forming roller sets, along the advancing direction of the blank, the angles α of all the left groove wall forming roller sets are arranged at intervals from small to large; when there are at least two sets of right groove wall forming roller sets, along the advancing direction of the blank, the angles α of all the right groove wall forming roller sets are arranged at intervals from small to large.

4. The method for forming a blank plate with a dovetail groove according to claim 1, characterized in that: The rectangular groove is processed and formed using at least one set of rectangular groove forming roller sets. This rectangular groove forming roller set includes a left side forming roller set and a right side forming roller set. Both the left side forming roller set and the right side forming roller set include a third forming roller and a fourth forming roller. The third forming roller is provided with an annular convex ring, and the fourth forming roller has an annular groove adapted to the rectangular groove. Let the width of the annular convex ring be d1, the groove width of the annular groove be d2, and the thickness of the blank be d3. Then, (d2 - 2d3) / 2 < d1 < d2 - 2d3.

5. The method for forming a blank plate with a dovetail groove according to claim 1, characterized in that: Before and after processing the rectangular groove on the blank, a leveling roller set is used to level and straighten the planar part of the blank.

6. The method for forming a blank plate with a dovetail groove according to claim 1, characterized in that: After the blank with the dovetail groove is processed, a cutting machine is used to cut the blank with the dovetail groove to a predetermined length.

7. Processing method of a square pyramid-shaped lamp post with dovetail grooves, wherein the four sides of the square pyramid-shaped lamp post are all provided with dovetail grooves, and the characteristics are as follows: First, use the method for forming the blank with the dovetail groove described in claim 1 to form trapezoidal blanks on each side, then spot-weld the trapezoidal blanks to assemble them into a quadrangular pyramid tube shape, and finally, full-weld them along the corner convex ridges to form the shape.

8. The processing method of the square pyramid tube-shaped lamp post with a dovetail groove according to claim 7, characterized in that: The corner of the quadrangular pyramid tube-shaped lamp post has a chamfered transition part. After forming the trapezoidal blanks on each side, first bend the edges of some trapezoidal blanks according to the size of the rounded corner, then spot-weld all the trapezoidal blanks to assemble them into a quadrangular pyramid tube shape, and finally, full-weld them along the corner convex ridges to form the shape.

9. The processing method of the square pyramid-shaped lamp pole with a dovetail groove according to claim 7, characterized in that: Each side of the quadrangular pyramid tube-shaped lamp post has a dovetail groove. When forming the trapezoidal blank, first process two parallel dovetail grooves on the blank, and then symmetrically cut diagonally between the two dovetail grooves to form two trapezoidal blanks each with a dovetail groove.

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