Thread screw-drawing three-point closing-in tool based on thread adjustment and spherical three-jaw structure

Abstract

The invention relates to a thread screw-drawing three-point closing-in tool based on thread adjustment and a spherical three-jaw structure, which comprises a positioning sleeve, a connecting rod is movably arranged in the positioning sleeve in the axial direction in a penetrating manner, a screw rod is arranged at the bottom of the connecting rod, and the bottom end of the screw rod is fixed on an external workbench; a spring sleeves the screw rod, a gasket sleeves one end, close to the positioning sleeve, of the spring, the top surface of the gasket is attached to the bottom end surface of the positioning sleeve, the bottom surface of the gasket abuts against the top end of the spring, a positioning hole is formed in the top end of the connecting rod, a positioning column is arranged on the connecting rod, and a plurality of spherical three-jaws are uniformly distributed on the peripheral side of the positioning column in the circumferential direction; one end of each spherical three-jaw is fixedly connected with a driving mechanism of an external closing-in machine, the other end of each spherical three-jaw is a spherical working end, and the spherical working ends face the thread drawing nail closing-in part at the top end of the positioning column, so that three-point synchronous extrusion closing-in is realized; the invention aims to solve the problems that a traditional tool is poor in positioning precision, low in efficiency, insufficient in applicability and difficult to adapt to different specifications of pulling nails.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing tooling, and relates to a threaded nail extraction three-point closing tooling based on thread adjustment and a spherical three-claw structure. Background Art

[0002] As a fastener that combines high locking reliability with the convenience of single-sided installation, threaded pull-out nails are widely used in fields with strict requirements on connection performance, such as aerospace, rail transportation, and high-end equipment manufacturing. Its core function is to use the "three-point closing" process on the end to extrude and deform the edge of the top cap inward, so that the threaded thin-walled parts and the screw fit tightly together, thereby achieving the effect of anti-loosening, anti-vibration, and stable clamping, while improving the tensile strength and fatigue life of the overall structure. In the aviation field, titanium alloy threaded pull-out nails are particularly critical. They not only have shear strength comparable to traditional bolts, but can also be installed on one side like ordinary blind rivets. They are suitable for scenarios with poor process access and insufficient installation space. They are core components to ensure connection stability in high shear load areas and improve assembly efficiency. The quality of the "three-point closing" process directly determines whether the locking torque of the threaded pull-out nail meets the standard, which in turn affects the safety of the entire connection structure.

[0003] In the large-scale production and actual application of threaded nails, the existing three-point closing process and supporting tooling have exposed many problems that restrict production efficiency and product quality stability. The first is the lack of versatility. Most tooling is only designed for threaded nails of a specific diameter or a specific interlayer length. When the processing specifications are switched, the main parts of the tooling need to be replaced as a whole. This not only prolongs the production preparation time, but also requires the storage of multiple sets of tooling of different specifications, resulting in a waste of equipment costs and storage space. The second is the poor positioning accuracy and parameter controllability. Traditional tooling lacks precise adjustment mechanisms. Key parameters such as closing position and extrusion depth mostly rely on manual experience and judgment, which makes it difficult to achieve quantitative control. As a result, problems such as closing offset and uneven depth are prone to occur in mass production. The locking torque of some products exceeds the standard range and needs to be reworked or even scrapped. Another issue is the imbalance between operational complexity and durability. Some high-precision tooling uses complex structures, which makes processing difficult and costly. Components are prone to wear and tear after long-term use, leading to high maintenance costs. Low-cost tooling, on the other hand, generally suffers from insufficient strength and easy damage, making it difficult to adapt to long-term continuous production needs. Furthermore, the operating procedures are cumbersome and require lengthy debugging by professionals, making them unable to meet the efficient processing requirements of modern production lines.

[0004] After searching and checking relevant information, the patent number is CN213575028U, and the patent name is a closing device for "three-point pressing" of threaded blind rivets. The device consists of a spring collet combination, a chuck and a limit rod, wherein the spring collet combination includes a spring collet, a perforated bushing and a pressing pin. The perforated bushing has circumferentially evenly spaced through holes to embed the pressing pins. The clamping force when the collet is closed is adjusted by the threaded cooperation between the spring collet and the chuck, and the relative position of the parts to be closed is controlled by the threaded cooperation between the limit rod and the spring collet. At the same time, different specifications of perforated bushings and pressing pins can be replaced to adapt to products of different diameters. Its advantages lie in the use of common components such as 5C standard spring collets, vertical or lathe-type chucks, etc., which simplify the structural design and greatly reduce processing and procurement costs. The basic control of clamping force and closing position is achieved through thread adjustment, and the operation is relatively convenient. However, the disadvantages are also quite obvious. The versatility is limited by the specifications of the spring collet, and the adaptability range for products with different interlayer lengths is narrow. In addition, there is a lack of parameter quantitative control methods, and the closing quality depends on manual experience. After long-term use, the fitting clearance between the hole bushing and the pressing pin is likely to lead to a decrease in accuracy, making it difficult to meet the diverse and high-precision production needs. Summary of the Invention

[0005] The present invention provides a three-point closing tool for threaded nail extraction based on thread adjustment and a spherical three-claw structure, which solves the problems of poor positioning accuracy, low efficiency, insufficient applicability, and difficulty in adapting to threaded nails of different specifications in the traditional three-point closing process for threaded nail extraction.

[0006] In order to solve the above problems, the technical solution adopted by the invention is: A three-point closing tool for threaded nail extraction based on thread adjustment and spherical three-claw structure, including a positioning column, a spherical three-claw, a connecting rod, a gasket, a positioning sleeve, a screw and a spring; the screw is the bottom bearing component of the tool, which is vertically fixed to an external workbench to support the spring, the gasket and the connecting rod, and the external thread at the top of the screw cooperates with the internal thread of the connecting rod, the spring is coaxially sleeved on the outside of the screw, the gasket fits horizontally on the top of the spring, and the inner hole of the gasket and the outer wall of the screw are gap-matched; the bottom of the connecting rod is provided with an internal threaded hole, which is connected to the thread at the top of the screw through the internal thread, and the end face of the bottom of the connecting rod is in contact with the upper surface of the gasket Abutment; the positioning sleeve is coaxially sleeved on the outside of the connecting rod, the inner wall of the positioning sleeve is clearance-matched with the outer wall of the connecting rod, and the bottom of the positioning sleeve is in contact with the external work table; the bottom of the positioning column is provided with an external threaded section, which is connected with the threaded hole at the top of the connecting rod through the external thread, and the upper end of the positioning column is adapted to the diameter of the through hole set on the rod part of the threaded nail to be closed, which is used for positioning and placing the threaded nail to be closed; the spherical three claws are multiple settings, which are evenly distributed in a circle with the axis of the positioning column as the center, one end of the spherical three claws is connected to the external closing machine drive mechanism, and the other end is a spherical working end, and the spherical working end faces the threaded nail at the top of the positioning column.

[0007] A three-point closing method for threaded nail extraction based on a three-point closing tool for threaded nail extraction based on thread adjustment and a spherical three-claw structure as described in any one of claims 1-8, characterized in that it includes the following steps: S1: Assembling the tool, fixing the screw rod vertically on an external workbench, inserting the spring coaxially into the screw rod, and placing a gasket on the top of the spring; screwing the internal threaded hole at the bottom of the connecting rod into the top of the screw rod until the bottom end face of the connecting rod fits with the upper surface of the gasket; inserting the positioning sleeve from the top of the connecting rod so that the bottom of the positioning sleeve fits with the workbench surface; selecting a spherical three-claw with a matching spherical radius according to the diameter of the threaded nail to be closed, and installing it on the external closing machine drive mechanism to ensure that the three spherical three-claws are evenly distributed around the circumference and the spherical working end faces the axis of the positioning column; S2: Positioning the parts, rotating the positioning column according to the length of the interlayer of the threaded nail to be closed. Adjust the depth of thread engagement with the connecting rod, read the adjustment depth through the scale line of the connecting rod, and make the distance between the top of the positioning column positioning hole and the spherical three-claw working end adapt to the interlayer length; put the threaded nail rod to be closed into the positioning column positioning hole, and ensure that the threaded nail top cap is above the top of the positioning column; S3: Closing operation, enter the preset closing value on the closing machine control panel, the closing value is determined according to the threaded nail locking torque standard, start the closing machine, the motor drives the three spherical three-claws to move synchronously centripetally, and the spherical working end applies uniform extrusion force to the edge of the threaded nail top cap to complete the three-point synchronous closing; S4: Reset and take out, after the closing is completed, the motor drives the spherical three-claw to move centrifugally to reset, and take out the threaded nail after closing; if processing parts of the same specification, repeat S2-S3; if changing specifications, repeat S1-S3.

[0008] The principles and benefits of this solution are: Through the synergy of modular structural design and thread adjustment mechanism, efficient and precise control of the three-point closing of threaded nail extraction is achieved. The screw serves as the bottom load-bearing foundation. After being fixed vertically to the workbench, the coaxially sleeved spring and the fitted gasket provide stable support for the upper connecting rod. At the same time, the elastic buffer of the spring can offset the local impact force generated during the closing process, avoiding damage caused by rigid collision of components. The connecting rod forms an adjustable vertical support structure through the cooperation of the bottom internal thread and the top thread of the screw, and the positioning sleeve is coaxially sleeved on the outside of the connecting rod, which not only limits the vertical movement trajectory of the connecting rod and prevents it from deflecting during the force application process, but also further improves the stability of the overall tooling by fitting with the workbench surface. The positioning column serves as the core of part positioning. The bottom external thread of the positioning column cooperates with the threaded hole at the top of the connecting rod. The depth of the thread engagement can be adjusted by rotation, and the distance between the top of the positioning column and the spherical three-claw working end can be accurately controlled to adapt to threaded nails with different interlayer lengths. At the same time, the through hole at the upper end of the positioning column is adapted to the diameter of the threaded nail rod, which can ensure that the axis of the part to be processed always remains centered during the closing process, avoiding uneven closing due to positioning offset. The spherical three-claw is evenly distributed in a circle with the axis of the positioning column as the center. One end is connected to the external closing machine drive mechanism, and the spherical working end at the other end is facing the nail top cap. When the closing machine is started, the motor drives the three spherical three-claws to move synchronously and centripetally. The spherical working end can apply uniform and symmetrical extrusion force to the edge of the top cap, so that the edge of the top cap is uniformly deformed inward along the circumferential direction, and finally achieves a three-point closing effect that meets the locking torque standard. During the whole process, the preset closing value can be input through the closing machine control panel, and combined with the thread adjustment scale of the positioning column, quantitative control of the closing parameters can be achieved to ensure the consistency of the closing quality of each part.

[0009] Compared with the existing technology, the existing technology mostly relies on manual experience to adjust the closing position and force, which is prone to problems such as closing offset and uneven depth. The present solution uses the threaded matching of the positioning column and the connecting rod with scale lines, which can intuitively read the adjustment depth and accurately adapt to different interlayer lengths. For example, when processing interlayer lengths of 5mm and 8mm with the same diameter, there is no need to change the tooling. Positioning can be achieved by simply rotating the positioning column to adjust the thread engagement depth. The positioning error can be controlled within ±0.1mm, which is much lower than the error range of ±0.5mm of traditional tooling; the preset closing value is input through the closing machine, and the spherical three claws are driven to extrude synchronously and centripetally, avoiding the uneven force caused by manual operation, so that the locking torque qualification rate is improved compared with the existing technology, and completely solves the problem that the locking torque in traditional processes is difficult to meet the standards. In terms of versatility, existing technologies often design tooling for a single specification of nail pullers. When changing specifications, the tooling components need to be replaced as a whole, which is time-consuming and costly. This solution, however, achieves multi-specification adaptation through modular design. Spherical three-claws with different spherical radii can be replaced according to the diameter of the nail puller. The replacement process only requires disassembly of the connection with the closing machine drive mechanism, which improves the replacement efficiency compared to traditional tooling. Different interlayer lengths can be adapted through thread adjustment, eliminating the need to stock multiple sets of positioning components, reducing tooling inventory costs and making it particularly suitable for multi-variety, small-batch production scenarios. When processing parts of the same specification, only the positioning and closing operations need to be repeated without re-debugging. Even when changing specifications, only the steps of replacing the spherical three-claws and adjusting the thread depth need to be supplemented, significantly reducing production preparation time. In terms of stability and durability, existing technologies either suffer from insufficient strength due to their simple structure, which makes it easy for components to deform after long-term use, or from high maintenance costs due to their complex structure. This solution uses high-strength metal components such as screws and positioning sleeves, combined with a spring buffer design, which can withstand the extrusion force during the closing process and reduce component wear.

[0010] Furthermore, the positioning hole at the top of the connecting rod is a stepped structure, which includes a first guide hole and a second guide hole arranged in sequence from top to bottom, and the diameter of the first guide hole is larger than the diameter of the second guide hole; the inner wall of the second guide hole is provided with an internal thread for cooperating with the external thread of the positioning column. Before the positioning column is threadedly connected to the second guide hole, the first guide hole can quickly limit the radial position of the positioning column to avoid the positioning column from being difficult to align the threads due to installation deviation, greatly reducing the assembly difficulty and improving the operating efficiency, while preventing the tooth profile damage caused by offset during thread matching, and extending the service life of the positioning column and the connecting rod; by rotating the positioning column to adjust the thread engagement depth with the second guide hole, the height of the top of the positioning column can be accurately controlled, thereby adapting to threaded nails of different interlayer lengths; and the thread matching is self-locking, which can stably maintain the position of the positioning column during the closing process, avoiding the axial force generated by the spherical three-claw extrusion causing the positioning column to be offset, and ensuring the closing consistency during three-point synchronous extrusion.

[0011] Furthermore, a U-shaped groove is provided at the bottom of the positioning sleeve, which is provided on the axis of the positioning sleeve and the connecting rod, and the axis of the vertical positioning sleeve passes through the bottom of the positioning sleeve. The through-type structure facilitates direct observation of the matching status of the boss and the groove body, timely detection of wear or offset problems, and reduced maintenance difficulty. The U-shaped groove is provided along the axis, which can ensure its coaxiality with the connecting rod and the screw, and avoid radial shaking of the connecting rod during movement due to the offset of the groove body, thereby ensuring the center positioning accuracy of the threaded pin at the top of the positioning column, and providing a stable reference for the spherical three-claw three-point synchronous extrusion; at the same time, the through-type U-shaped groove can form a natural chip removal and heat dissipation channel. During the threaded pin closing process, the iron chips or impurities generated can be discharged in time to prevent them from accumulating at the bottom of the positioning sleeve and affecting the normal operation of the spring and gasket. It can also assist in dissipating the heat generated by the friction of the components, thereby extending the service life of vulnerable parts such as springs and gaskets, and avoiding the defects of traditional closed grooves that are easy to accumulate chips and difficult to dissipate heat.

[0012] Furthermore, a boss is provided at the bottom of the connecting rod, and the diameter of the boss is larger than the diameter of the connecting rod, and the boss is matched with the clearance of the side wall of the U-shaped groove. The design of the boss diameter being larger than the connecting rod cooperates with the side wall of the U-shaped groove to form a two-way radial limit, and the outer peripheral surface of the boss fits with the side wall of the U-shaped groove, which can strictly limit the radial deviation of the connecting rod during axial movement, and avoid the lateral force generated when the spherical three-claw squeezes and pulls out the nail causing the connecting rod to tilt, thereby ensuring that the center reference of the nail pulling at the top of the positioning column is not offset, providing a key guarantee for the accuracy of the three-point synchronous closing; at the same time, compared with the design without boss, this structure can disperse the contact stress between the connecting rod and the positioning sleeve, prevent the increase of the fitting clearance due to local wear after the connecting rod is subjected to long-term force, and extend the service life of the overall structure.

[0013] Furthermore, the gasket is a circular structure made of No. 45 steel, with a thickness of 2 to 3 mm and an inner diameter 0.1 to 0.2 mm larger than the outer diameter of the screw. The symmetrical characteristics of the circular structure can ensure that the contact area between the gasket and the bottom of the positioning sleeve and the top of the spring is uniform, avoiding the positioning sleeve from being sunken or the spring from being deformed due to local force concentration. No. 45 steel, as a medium-carbon steel, has high hardness and deformation resistance, can withstand the axial force generated by long-term extrusion of the spring, prevent the gasket from being plastically deformed due to the material being too soft, or from being broken due to the material being too brittle, thereby extending the service life of the gasket. The thickness can avoid the lack of structural rigidity caused by too thin thickness, and prevent the thickness from increasing the overall volume of the tooling and affecting the matching accuracy between components. The inner diameter is larger than the outer diameter of the screw. The gap can not only avoid the gasket and the screw from getting stuck due to dimensional interference or processing error, but also ensure that the gasket can move flexibly along the screw axis with the connecting rod to meet the adjustment requirements of different closing depths. It can also compensate for the slight radial deviation during the operation of the tooling through the gap, prevent the gasket from getting stuck due to component assembly deviation, and avoid radial shaking of the gasket caused by excessive gap, thereby ensuring the stability of the spring force transmission.

[0014] Furthermore, the second positioning hole is threadedly connected to the connecting part on the positioning column. The detachability and adjustability of the threaded connection allow the tooling to easily adapt to threaded puller nails of different interlayer lengths. By rotating the positioning column, the depth of thread engagement with the second positioning hole can be accurately adjusted, thereby changing the height of the top end of the positioning column. The closing requirements of parts of different sizes can be met without replacing the entire set of positioning components, avoiding the cost waste of traditional tooling and the efficiency loss of frequent part replacement; at the same time, the detachability of the threaded connection also facilitates the separate maintenance or replacement of the positioning column, reducing the overall maintenance cost of the tooling. At the same time, the self-locking characteristics of the threaded connection can provide a stable positioning reference for the closing process. When the spherical three-claw applies circumferential extrusion to the threaded puller nail, the friction force of the threaded engagement surface can effectively prevent the positioning column from shifting axially or radially, ensuring that the puller nail at the top end of the positioning column is always in the preset closing position, avoiding problems such as asymmetric closing and substandard locking torque caused by loose positioning.

[0015] Furthermore, an annular placement platform is integrally formed in the middle of the positioning column, the diameter of the placement platform is adapted to the diameter of the first guide hole of the connecting rod, and the bottom surface of the placement platform is in contact with the step surface of the first guide hole. The precise adaptation of the placement platform diameter to the diameter of the first guide hole can form a radial rigid constraint, and the outer peripheral surface of the annular placement platform is in contact with the inner wall of the first guide hole, which can strictly limit the radial shaking of the positioning column during assembly and closing, ensuring that the axis of the positioning column, the connecting rod and the positioning sleeve are completely aligned, providing a concentric reference for the synchronous extrusion of the spherical three-claw three-point, avoiding the problems of asymmetric nail withdrawal and dimensional deviation caused by the offset of the positioning column; compared with the design without a placement platform, this radial constraint It can disperse the lateral force on the positioning column, prevent the positioning column from bending and deforming due to long-term stress, and extend its service life; the fit between the bottom surface of the placement table and the step surface of the first guide hole can achieve reliable axial limitation. When the positioning column is adjusted in height through the threaded connection of the second guide hole, the fit between the bottom surface of the placement table and the step surface can accurately control the maximum insertion depth of the positioning column, and avoid the top of the positioning column exceeding the preset position due to excessive thread adjustment. At the same time, during the closing process, the fitting surface can withstand the axial reaction force transmitted by the spherical three-claw, and prevent the positioning column from sinking due to force and affecting the closing accuracy; and the one-piece structural design eliminates assembly gaps, and avoids loosening or displacement that may occur in the split placement table.

[0016] Furthermore, a waist-shaped hole is provided at the connection end between the spherical three-claw and the external closing machine driving mechanism, and the waist-shaped hole is arranged along the length direction of the spherical three-claw. By adjusting the position of the bolt in the waist-shaped hole, the distance between the spherical three-claw and the positioning column can be fine-tuned. The length direction adjustment feature of the waist-shaped hole allows the tooling to adapt to threaded pull-out nails of different diameters without replacing the spherical three-claw. When faced with pull-out nails with smaller diameter differences, there is no need to disassemble the driving mechanism and replace the three-claws of the corresponding specifications. The distance between the spherical working end of the three-claw and the positioning column can be adjusted by loosening the bolts and moving the spherical three-claw along the waist-shaped hole, so that the three-claw can always form a uniform three-point extrusion of the circumference of the circle on the pull-out nail, avoiding efficiency loss and cost waste caused by frequent replacement of parts, and greatly improving the compatibility of the tooling with parts of multiple specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural schematic diagram of the present invention; Figure 3 It is a structural schematic diagram of the present invention; DETAILED DESCRIPTION The reference numerals in the drawings of the specification include: positioning sleeve 1, connecting hole 2, U-shaped groove 3, connecting rod 4, gasket 5, screw 6, spring 7, boss 8, spherical three-claw 9, spherical working end 10, screw with closed end 11, first guide hole 12, second guide hole 13, positioning column 14, connecting part 15, positioning section 16 Example 1, as Figure 1-3 As shown, a threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw 9 structure includes a screw rod 6, with the screw rod 6 as the bottom core load-bearing component, and its axis is perpendicular to the table surface of the external workbench. The bottom of the screw rod 6 is fixedly connected to the external workbench 19 by welding, or can be detachably fixed by bolts to facilitate later maintenance and replacement. The external thread specification of the top of the screw rod 6 is M20×2, which is used to cooperate with the internal thread hole at the bottom of the connecting rod 4.

[0018] The spring 7 is coaxially sleeved on the outside of the screw 6. The material of the spring 7 is 65Mn steel, the wire diameter is 5mm, and the free length is 80mm. The bottom end of the spring 7 fits tightly against the table surface of the external workbench, and the top end abuts against the lower surface of the gasket 5; the gasket 5 is a circular structure, made of 45 steel, 2.5mm thick, and the inner diameter is 0.15mm larger than the outer diameter of the screw 6. The upper surface of the gasket 5 is completely fitted with the bottom end face of the positioning sleeve 1, and the outer diameter of the gasket 5 is adapted to the inner diameter of the screw 6, ensuring that the gasket 5 can only move vertically along the axis of the screw 6 without radial offset.

[0019] A connecting rod 4 is provided on the positioning sleeve 1. The connecting rod 4 is cylindrical as a whole, with a diameter of 40mm and a length of 120mm. An internal threaded hole is provided in the center of its bottom, which is engaged with the external thread at the top of the screw 6 through the internal thread to realize the detachable fixation of the connecting rod 4 and the screw 6. A boss 8 is integrally formed on the outer side of the bottom of the connecting rod 4. The boss 8 has a diameter of 48mm and a thickness of 10mm. The outer peripheral surface of the boss 8 is clearance-matched with the side wall of the U-shaped groove 3 on the inner wall of the positioning sleeve 1 to limit the radial shaking of the connecting rod 4. A stepped positioning hole is provided in the center of the top of the connecting rod 4. The positioning hole includes a first guide hole 12 and a second guide hole 13 arranged in sequence from top to bottom, wherein the diameter of the first guide hole 12 is 30mm and the depth is 20mm, the diameter of the second guide hole 1312 is 25mm and the depth is 30mm, and the inner wall of the second guide hole 1312 is provided with an internal thread. The specification of the internal thread is M24×1.5, which is used to cooperate with the connecting part 15 at the bottom of the positioning column 14.

[0020] The positioning sleeve 1 is a cylindrical hollow structure made of 40Cr steel, with an outer diameter of 60mm, an inner diameter of 50mm and a length of 150mm; the positioning sleeve 1 is coaxially sleeved on the outside of the connecting rod 4, and its bottom fits tightly with the surface of the external workbench, and can be fixed to the workbench by bolts passing through the connecting hole 2 on the side wall of the positioning sleeve 1; a U-shaped groove 3 is opened at the bottom of the positioning sleeve 1 along the axial direction, and the U-shaped groove 3 has a width of 48.2mm and a depth of 50mm, and passes through the bottom of the positioning sleeve 1 perpendicular to the axis.

[0021] The positioning column 14 is cylindrical as a whole, made of cemented carbide, with a diameter of 25mm and a total length of 80mm; a connecting part 15 is provided at the bottom of the positioning column 14, with an external thread specification of M24×1.5, which is engaged with the internal thread of the second guide hole 13 at the top of the connecting rod 4 through the external thread to realize the detachable fixation of the positioning column 14 and the connecting rod 4; an annular placing platform is integrally formed in the middle part of the positioning column 14, with a diameter of 30mm and a thickness of 10mm. The diameter of the placing platform is completely adapted to the diameter of the first guide hole 12, and the bottom surface of the annular placing platform is tightly fitted with the step surface of the first guide hole 12 to form an axial limit; the upper end of the positioning column 14 is a positioning section 16 with a diameter of 12mm, which is adapted to the diameter of the through hole of the rod of the threaded nail to be closed, and is used to insert the through hole of the rod of the threaded nail to be closed to realize the positioning and placement of the nail.

[0022] There are three spherical three-claws 9 in total, made of Cr12MoV steel. The length of each spherical three-claw 9 is 150 mm. One end is connected to the external closing machine drive mechanism through an adjusting bolt. A waist-shaped hole is provided at the connecting end. The waist-shaped hole is arranged along the length direction of the spherical three-claw 9, with a length of 20 mm and a width of 10 mm. The other end is processed into a spherical working end 10; the three spherical three-claws 9 are evenly distributed in a circle with the axis of the positioning column 14 as the center, and the angle between the spherical three-claws 9 is 120°. The spherical working end 10 is facing the threaded nail to be closed at the top of the positioning column 14, and the distance between the spherical working end 10 and the nail top cap can be adjusted through the waist-shaped hole.

[0023] Tooling assembly process Weld the screw 6 vertically to the preset position of the external workbench to ensure the vertical error between the axis of the screw 6 and the workbench surface. After welding, use an angle grinder to grind the weld to avoid protrusions affecting subsequent component assembly.

[0024] Insert the spring 7 coaxially into the screw 6, ensuring that the bottom of the spring 7 fits tightly against the work surface; insert the gasket 5 from the top of the screw 6, making the lower surface of the gasket 5 fit against the top of the spring 7, and check whether the gasket 5 can slide freely along the screw 6.

[0025] Hold the connecting rod 4, align the internal threaded hole at its bottom with the external thread at the top of the screw 6, and slowly rotate it until the bottom end surface of the connecting rod 4 fits into the upper surface of the gasket 5; during the rotation, observe whether the connecting rod 4 is vertical to ensure that there is no tilt.

[0026] Insert the positioning sleeve 1 from the top of the connecting rod 4 so that the inner wall of the sleeve fits with the outer wall of the connecting rod 4 until the bottom of the positioning sleeve 1 fits with the work surface; adjust the position of the positioning sleeve 1 so that the U-shaped groove 3 is aligned with the boss 8 of the connecting rod 4, and the gap between the outer peripheral surface of the boss 8 and the side wall of the U-shaped groove 3 is uniform.

[0027] According to the interlayer length of the M6 ​​threaded nail to be processed, such as the initial processing of 5mm interlayer nails, rotate the positioning column 14, screw its bottom external thread into the second guide hole 13 internal thread of the connecting rod 4, read the adjustment depth through the scale line of the connecting rod 4, and make the distance between the top positioning hole of the positioning column 14 and the working end of the spherical three-claw 9 be 5mm, until the bottom surface of the annular placement table of the positioning column 14 fits with the step surface of the first guide hole 12.

[0028] Select a spherical three-claw 9 with a spherical radius of 6mm, install it on the output end of the closing machine drive mechanism through an M8 bolt, adjust the position of the three spherical three-claws 9, ensure that they are evenly distributed in a 120° circle with the axis of the positioning column 14 as the center, and the distance between the spherical working end 10 and the axis of the positioning column 14 is 6mm; fine-tune the bolt position through the waist hole to make the coaxial error between the spherical working end 10 and the positioning hole at the top of the positioning column 14 .

[0029] Check the specifications of the M6 ​​threaded nail to be closed, the rod diameter is 6mm, the interlayer length is 5mm, the top cap diameter is 12mm, and confirm that the diameter of the positioning hole at the top of the positioning column 14 and the adjustment depth are both suitable.

[0030] Hold the threaded nail and slowly place its rod into the positioning part of the positioning column 14 until it reaches the position of the boss 8, ensuring that the nail rod fits the positioning part without looseness and the nail cap is located above the boss 8 on the positioning column 14.

[0031] Enter the preset closing value on the closing machine control panel and require the locking torque according to the M6 ​​thread screw tightening torque standard. , correspondingly set the output force of the closing machine , the closing stroke is 2mm. Through preliminary test calibration, this parameter can ensure that the edge of the top hat is evenly deformed to meet the torque requirements.

[0032] Press the start button of the closing machine, the motor drives the three spherical claws 9 to move synchronously towards the centripetal, and the moving speed The spherical working end 10 gradually contacts the edge of the nail cap and applies uniform extrusion force; during the process, the pressure value is monitored in real time by the pressure sensor provided by the sealing machine to ensure that the pressure is stable. If the pressure fluctuation exceeds the range, the equipment will automatically pause and alarm, and restart after troubleshooting.

[0033] When the spherical three-claw 9 moves to the preset stroke, the closing machine automatically stops driving, maintains the pressure for 3 seconds, and then releases the pressure to complete the three-point synchronous closing.

[0034] Press the reset button of the closing machine, and the motor drives the spherical three claws 9 to move centrifugally to the initial position. During the reset process, observe whether the three claws are synchronized.

[0035] Remove the closed threaded nail from the positioning column 14 and check the closed state of the threaded nail to see if the edge is evenly deformed inward without cracks or deflection.

[0036] If you continue to process the same specification of pull-out nails, there is no need to re-adjust the tooling; if you change the specification, such as processing 8mm sandwich M6 pull-out nails, rotate the positioning column 14 to adjust the depth, and use the scale line to make the distance between the positioning column 14 and the working end of the three-claw 8mm, without replacing other parts; if you change to M8 pull-out nails, you need to replace the spherical three-claw 9 with a spherical radius of 8mm, and fine-tune the position of the three-claw through the waist hole to ensure adaptation.

[0037] The above are only embodiments of the present invention. The common knowledge of the specific structures and characteristics known in the scheme is not described in detail here. Those of ordinary skill in the art are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Those of ordinary skill in the art can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical well-known structures or well-known methods should not become obstacles for those of ordinary skill in the art to implement this application. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the structure of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the records of the specific implementation methods in the specification can be used to interpret the content of the claims.

Claims

1. A three-point closing tool for threaded nail extraction based on thread adjustment and spherical three-claw structure, characterized in that: The top end of the spring is provided with a threaded hole, and the bottom end of the spring is provided with a threaded hole, and the bottom end of the spring is connected with a threaded hole.

2. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: The positioning hole at the top end of the connecting rod is a stepped structure, which includes a first guide hole and a second guide hole arranged in sequence from top to bottom. The diameter of the first guide hole is larger than the diameter of the second guide hole; the inner wall of the second guide hole is provided with an internal thread for cooperating with the external thread of the positioning column.

3. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: A U-shaped groove is provided at the bottom of the positioning sleeve. The U-shaped groove is provided on the axis of the positioning sleeve and the connecting rod and passes through the bottom of the positioning sleeve perpendicular to the axis of the positioning sleeve.

4. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: A boss is provided at the bottom of the connecting rod. The diameter of the boss is larger than the diameter of the connecting rod, and the boss is in clearance fit with the side wall of the U-shaped groove.

5. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: The gasket is a circular structure, made of 45# steel, has a thickness of 2-3mm, and an inner diameter 0.1-0.2mm larger than the outer diameter of the screw.

6. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: The second positioning hole is threadedly connected to a connecting portion provided at the lower end of the positioning column.

7. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: An annular placement platform is integrally formed in the middle of the positioning column. The diameter of the placement platform is adapted to the diameter of the first guide hole of the connecting rod, and the bottom surface of the placement platform is in contact with the step surface of the first guide hole.

8. The threaded nail extraction three-point closing tool based on thread adjustment and spherical three-claw structure according to claim 1 is characterized in that: A waist-shaped hole is provided at the connection end between the spherical three-claw and the external closing machine driving mechanism. The waist-shaped hole is arranged along the length direction of the spherical three-claw. By adjusting the position of the bolt in the waist-shaped hole, the distance between the spherical three-claw and the positioning column can be fine-tuned.

9. A method for threaded nail extraction and three-point closing of a threaded nail extraction and three-point closing tool based on thread adjustment and a spherical three-claw structure according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Tooling assembly: Fix the screw rod vertically to the external workbench, insert the spring coaxially into the screw rod, and place a gasket on the top of the spring; screw the internal threaded hole at the bottom of the connecting rod into the top of the screw rod until the bottom end face of the connecting rod is in contact with the upper surface of the gasket; insert the positioning sleeve from the top of the connecting rod until the bottom of the positioning sleeve is in contact with the workbench surface; select a spherical three-jaw with a suitable spherical radius according to the diameter of the threaded screw to be closed, and install it on the external closing machine drive mechanism, ensuring that the three spherical three-jaws are evenly distributed around the circumference and the spherical working end is facing the axis of the positioning column; S2: Position the parts. According to the length of the interlayer of the threaded screw to be closed, rotate the positioning column to adjust the depth of the thread engagement with the connecting rod. Read the adjustment depth from the scale line on the connecting rod to make the distance between the top of the positioning column positioning hole and the working end of the spherical three-claw adapt to the interlayer length; insert the rod of the threaded screw to be closed into the positioning column positioning hole, ensuring that the top cap of the threaded screw is above the top of the positioning column; S3: Closing operation: Enter the preset closing value on the closing machine control panel. The closing value is determined according to the thread extraction screw locking torque standard. The closing machine is started, and the motor drives the three spherical claws to move synchronously and centripetally. The spherical working end applies uniform extrusion pressure to the edge of the thread extraction screw cap to complete the three-point synchronous closing. S4: Reset and remove the part. After the closing is completed, the motor drives the spherical three claws to move centrifugally and reset, and the thread extraction screw is removed after closing. If processing parts of the same specification, repeat S2-S3. If you change the specifications, repeat S1-S3.

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