Workpiece clamping device and automatic clamp replacing system and method

Abstract

The invention discloses a workpiece clamping device and an automatic clamp replacing system and method.The workpiece clamping device is characterized in that a position sensor, a limiting piece and a limiting piece controller are fixedly mounted on a clamp mounting base, the clamp mounting base is provided with a mounting groove matched with the circumferential side of a clamp in shape, and the mounting groove is provided with a first limiting groove; the circumferential side of the clamp is provided with an induction piece corresponding to the position sensor, a second limiting groove corresponding to the limiting piece and a limiting protrusion matched with the first limiting groove, and the inner circumferential side of the clamp is provided with a clamping groove used for clamping a workpiece. The clamp mounting seat and the driving device thereof are fixedly and reliably mounted, the clamp and the clamp mounting seat are detachably mounted, the sensing part triggers the position sensor to enable the limiting part controller to drive the limiting part to lock the clamp, pipe fitting machining clamps of different specifications are fully automatically replaced in the machining process, and the working efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of clamps, in particular to a workpiece clamping device, a clamp automatic replacement system and method. BACKGROUND

[0002] Referring to the Chinese patent document with publication number "CN116079082B", a chamfering method and device for aerospace ducts are disclosed. During chamfering, one end of the duct is sleeved on an inner support, two clamping plates are moved axially from the outside of the duct to clamp the conical head pull rod, the inner support is opened to support the duct from the inside, the cutter head is rotated to drive the cutter blade and the inner support to rotate, the cutter head is axially moved to drive the cutter blade and the inner support to move axially, the cutter blade is axially moved to cut the end of the duct, until the duct is chamfered; wherein part of the inner support is located between the two clamping plates; the cutter blade rotates around the axis of the duct, and then the cutter blade moves axially to cut the end of the duct supported by the inner support, until the duct is chamfered; the duct is removed. Although the application can replace the clamp according to different pipe specifications, it still needs to manually replace the clamp. If the pipe specifications are changed, the production line needs to be paused for manual clamp replacement, which greatly reduces the production efficiency. Moreover, if the pipe specifications are multiple and frequently changed, it affects the processing rhythm and pace of the entire production line, as well as the positioning accuracy. For large pipe diameter specifications, the involved clamp is heavy, which further affects the clamp replacement time. SUMMARY

[0003] To solve the above technical problems, the purpose of the present application is to provide a workpiece clamping device, a clamp automatic replacement system and method, which can automatically replace workpiece machining clamps of different specifications during machining process, and improve work efficiency.

[0004] To achieve the above purpose, the present application adopts the following technical solutions:

[0005] A workpiece clamping device, comprising two clamp mounting seats and two clamps.

[0006] The position sensor, the limiting piece and the limiting piece controller are fixedly installed on the clamp mounting seat, the clamp is a semi-cylindrical shape, the clamp mounting seat has a semi-cylindrical mounting groove matched with the circumferential side of the clamp, the mounting groove is provided with a first limiting groove and a limiting structure, the clamp is provided with a sensing piece corresponding to the position sensor, a second limiting groove corresponding to the limiting piece, a limiting protrusion matched with the first limiting groove in shape and a stop portion matched with the outer peripheral contour of the limiting structure on the circumferential side, the limiting protrusion extends along the circumferential side of the clamp to form an arc-shaped flange, the clamp is provided with a clamping groove for clamping a workpiece on the inner circumferential side, and at least two circular holes are formed between the two end portions of the clamp, when the clamp is in the target position, the limiting protrusion is in the first limiting groove, the limiting piece enters or is located above the second limiting groove, the sensing piece is positionally corresponding to the position sensor, and the stop portion is stopped by the limiting structure.

[0007] The mounting grooves on the two clamps are oppositely arranged, when the workpiece needs to be clamped, the two clamp mounting seats are driven to approach each other, so that the workpiece is clamped by the clamping grooves of the two clamps; when the workpiece needs to be unloaded or the clamp needs to be replaced, the two clamp mounting seats are driven to move away from each other.

[0008] In some embodiments, when the clamp is in the target position, the stop portion is located at the lower end of the circumferential side of the clamp, the second limiting groove is located at the upper end of the circumferential side of the clamp, the stop portion is stopped by the limiting structure, and the limiting structure is closer to the inner circumferential side than the stop portion.

[0009] In some embodiments, the limiting protrusion has a notch at the lower end of the clamp, the stop portion is the end portion of the notch, the limiting structure is a limiting pin arranged at the lower end of the mounting groove corresponding to the notch, and when the clamp is in the target position, the limiting pin can abut against the end portion of the notch.

[0010] In some embodiments, the clamp is fixedly installed with a mounting seat on the circumferential side, the sensing piece is installed in the mounting seat, and a give-way groove is arranged on the inner side of the first limiting groove, so that the mounting seat and the sensing piece can pass through when the clamp rotates.

[0011] In some embodiments, two circular holes are formed between the two end portions of the clamp, and the two circular holes are symmetrically distributed with respect to the clamping groove.

[0012] In some embodiments, a base is further included, the base is fixedly installed with a fixture assembly mounting plate at the front end, two fixture mounting seats are slidingly installed on the fixture assembly mounting plate, a first driving mechanism is fixedly installed on the fixture assembly mounting plate, the first driving mechanism is used for driving the two fixture mounting seats to move close to or away from each other in a direction perpendicular to the extension direction of the machine table, the base is slidingly connected with the machine table and can slide along the extension direction of the machine table, a machining mechanism for machining the workpiece is further arranged on the base, the machining mechanism is slidingly installed above the base, a second driving mechanism is further fixedly installed above the base, the second driving mechanism is used for driving the machining mechanism to slide relative to the base in the extension direction of the machine table, a stop mechanism is further arranged beside the machining mechanism, when the workpiece is installed into the fixture, the stop arm of the stop mechanism can be rotated to be between the machining mechanism and the fixture, the stop arm can stop the front end of the workpiece to determine the machining position of the workpiece, after the fixture clamps the workpiece, the stop arm is rotated to be away from the machining mechanism and the fixture, and the distance between the stop arm and the fixture can be adjusted by a third driving mechanism.

[0013] The application further provides a fixture automatic replacement system, which comprises a mechanical arm for clamping a fitting part, a tool magazine for placing a to-be-installed fixture, and the workpiece clamping device.

[0014] In some embodiments, the end gripper of the mechanical arm is a two-finger gripper, the two fingers are provided with protrusions protruding laterally, the two protrusions are arranged in opposite directions, when the gripper is opened to clamp the fixture, the two fingers extend into the two round holes of the fixture from the same direction, and the two protrusions extend to the other side of the round holes.

[0015] In some embodiments, the two-finger gripper is eccentrically arranged on the end rotating part of the mechanical arm, and when the two-finger gripper clamps the fixture, the two-finger gripper can rotate around the rotating shaft of the fixture.

[0016] The application further provides a fixture automatic replacement method, which comprises the following steps:

[0017] S1: the two fixture mounting seats are driven to move away from each other, and the limiting piece controller drives the limiting piece to exit from the second limiting groove;

[0018] S2: the end rotating part of the mechanical arm is aligned with the center of the fixture;

[0019] S3: the gripper moves forward and clamps the fixture, after clamping, the end rotating part of the mechanical arm rotates around the rotating shaft of the fixture, the fixture is translated to remove the mechanical arm after the limiting is released, the fixture is taken off from the fixture mounting seat, and the fixture is placed in the corresponding position of the tool magazine;

[0020] S4: the mechanical arm clamps the to-be-replaced fixture from the tool magazine;

[0021] S5: The robotic arm moves the fixture to the mounting groove, and the robotic arm is translated so that the limiting protrusion enters the first limiting groove. The end rotating part of the robotic arm rotates around the rotation axis of the fixture, so that the fixture rotates to the target position. After it is in place, the stop part on the fixture is stopped by the limiting structure.

[0022] S6: The sensing element triggers the position sensor, causing the limit element controller to drive the limit element to be inserted into the second limit groove.

[0023] The present invention has the following beneficial effects:

[0024] The present invention discloses a workpiece clamping device and an automatic fixture changing system. By separating the fixture from the fixture mounting base, and fixing the fixture mounting base and its driving device securely, the fixture and the fixture mounting base can be detached, thus separating their functions and enabling more convenient replacement of different specifications of pipe fitting processing fixtures. Furthermore, the circumferential side of the fixture has a large area of ​​direct contact with the fixture mounting base, which can improve the clamping stability of the fixture. The automatic fixture changing method uses a sensor to trigger a position sensor, which in turn drives a limiter controller to lock the fixture. This enables fully automatic replacement of different specifications of pipe fitting processing fixtures during the processing, significantly improving work efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the workpiece clamping device.

[0026] Figure 2 This is a cross-sectional view of the workpiece clamping device (the limiting member is inserted in the second limiting groove).

[0027] Figure 3 This is a cross-sectional view of the workpiece clamping device (the limiting member is not inserted into the second limiting groove).

[0028] Figure 4 This is one of the structural schematic diagrams of the clamp mounting base.

[0029] Figure 5 This is the second structural schematic diagram of the fixture mounting base.

[0030] Figure 6 This is one of the structural schematic diagrams of the fixture.

[0031] Figure 7 This is the second schematic diagram of the fixture.

[0032] Figure 8 This is a schematic diagram of an automatic fixture changing system.

[0033] Figure 9 This is a partial structural diagram of an automatic fixture changing system.

[0034] Figure 10 This is a schematic diagram of the robotic arm gripper.

[0035] Figure 11 This is a schematic diagram of the structure when the robotic arm grips the tool.

[0036] Explanation of reference numerals in the attached drawings: 1. Workpiece clamping device; 12. Fixture; 121. Circumferential side; 1211. Stop; 122. Sensing element; 123. Second limiting groove; 124. Limiting protrusion; 125. Inner circumferential side; 1251. Clamping groove; 126. Circular hole; 13. Fixture mounting base; 131. Position sensor; 132. Limiting element; 133. Limiting element controller; 134. Mounting groove; 1341. 1. First limiting groove; 1342. Limiting structure; 1343. Clearance groove; 2. Robotic arm; 21. Finger gripper; 211. Protrusion; 22. Gripping block; 23. Finger cylinder; 24. End-effector rotation; 3. Tool magazine; 4. Base; 41. Fixture assembly mounting plate; 411. First drive mechanism; 42. Machining mechanism; 43. Second drive mechanism; 44. Stop mechanism; 441. Stop arm; 45. Third drive mechanism. Detailed Implementation

[0037] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0038] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0039] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] refer to Figures 1-3 The workpiece clamping device of this embodiment includes two clamp mounting bases 13 and two clamps 12;

[0042] A position sensor 131, a limiting member 132, and a limiting member controller 133 are fixedly mounted on the fixture mounting base 13. The fixture 12 is semi-cylindrical. The fixture mounting base 13 has a semi-cylindrical mounting groove 134 that matches the shape of the circumferential side 121 of the fixture 12. The mounting groove 134 is provided with a first limiting groove 1341 and a limiting structure 1342. The fixture 12 has a sensing element 122 corresponding to the position sensor 131, a second limiting groove 123 corresponding to the limiting member 132, a limiting protrusion 124 that matches the shape of the first limiting groove 1341, and a limiting structure 1342 on its circumferential side 121. The stop portion 1211 is matched with the outer peripheral contour of 342. The limiting protrusion 124 extends along the circumferential side of the clamp 12 to form an arc-shaped flange. The clamp 12 is provided with a clamping groove 1251 for clamping the workpiece on the inner peripheral side 125. At least two through circular holes 126 are provided between the two ends of the clamp 12. When the clamp 12 is in the target position, the limiting protrusion 124 is in the first limiting groove 1341, the limiting member 132 enters the second limiting groove 123 or is located above the second limiting groove 123, the sensing member 122 corresponds to the position sensor 131, and the stop portion 1211 is stopped by the limiting structure 1342.

[0043] The mounting grooves 134 on the two clamps 12 are arranged opposite each other. When a workpiece needs to be clamped, the two clamp mounting seats 13 are driven to move closer to each other, so that the two clamps 12 move closer to each other, and the workpiece is surrounded and clamped by the clamping grooves 1251 of the two clamps 12. When the workpiece needs to be unloaded or the clamps 12 need to be replaced, the two clamp mounting seats 13 are driven to move away from each other.

[0044] The workpiece clamping device of this embodiment can be used to clamp various types of workpieces, especially to stably clamp tubular or cylindrical workpieces with an arc-shaped outer periphery. In this embodiment, when installing the clamp 12, the robotic arm 2 clamps the clamp 12 and places the clamp 12 into the mounting groove 134 at a predetermined angle, so that the circumferential side 121 of the clamp 12 fits against the mounting groove 134 and the limiting protrusion 124 cooperates with the first limiting groove 1341, and then rotates the clamp 12 in a predetermined direction until... When the target position is reached, the stop 1211 is stopped by the limiting structure 1342. The sensing element 122 triggers the position sensor 131, and the limiting element controller 133 drives the limiting element 132 to insert into the second limiting groove 123, thereby fixing the clamp 12 onto the clamp mounting base 13. When it is necessary to remove the clamp 12, the limiting element controller 133 drives the limiting element 132 to move out of the second limiting groove 123, and the robotic arm 2 clamps the clamp 12 and removes it from the clamp mounting base 13. The predetermined direction is the rotation direction in which the stop 1211 moves towards the limiting structure 1342. If the stop 1211 is limited by the limiting structure 1342 when the robotic arm 2 clamps the clamp 12 and removes it directly from the clamp mounting base 13, the clamp 12 needs to be rotated in the opposite direction of the predetermined direction until it can be removed.

[0045] Regarding the switching of clamp 12 types for different workpieces, referring to Chinese patent document with publication number "CN116079082B", the time-consuming replacement of clamp 12 in the prior art is often due to the use of many fasteners such as screws when fixing clamp 12, which are difficult to disassemble and assemble. Referring to Chinese patent document with publication number "CN223466164U", although this application can disassemble and assemble clamp 12 more simply, the efficiency of manual replacement is still relatively low. Replacing clamp 12 still requires three steps: 1. Pressing down the two limit plates to remove clamp 12, 2. Replacing clamp 12, 3. Pressing down the two limit plates to install the new clamp 12. If a robotic arm 2 is used for replacement, one robotic arm 2 is difficult to complete such complex steps. Using two or more robotic arms 2 will increase the cost of robotic arms 2 and space costs. The curved plate is also difficult to be stably clamped by the robotic arm 2. In this embodiment, the clamp 12 and the clamp mounting base 13 are separated into independent modules. The clamp mounting base 13 can be fixedly connected to the drive mechanism using fasteners or other fixing methods to ensure the overall stability. The clamp 12 and the clamp mounting base 13 are fixedly connected by the limiting member 132 and the limiting protrusion 124. The limiting protrusion 124 entering the first limiting groove 1341 means that the limiting protrusion 124 can enter the first limiting groove 1341 when the clamp 12 is moved, without the need for control like the limiting member 132 to achieve the limiting function.

[0046] The limiting element 132 and the limiting protrusion 124 work together to achieve two functions: firstly, to achieve stable positioning of the fixture 12 on the fixture mounting base 13 with six degrees of freedom. (Refer to...) Figure X When the clamp 12 enters the clamp mounting base 13, its freedom is restricted to a certain extent by the mounting groove 134. The limiting member 132 and the limiting protrusion 124 cooperate to fix the clamp 12 stably and completely on the clamp mounting base 13. The limiting member 132 and the limiting protrusion 124 at different positions on the periphery can provide support for the clamp 12 on the clamp mounting base 13 at different positions, making the support stability and reliability higher.

[0047] The limiting component 132 is controlled by the limiting component controller 133. After reaching the target position, the position sensor 131 is triggered, causing the limiting component controller 133 to drive the limiting component 132 to insert into the second limiting groove 123. In this embodiment, the setting of the limiting component controller 133 and the position sensor 131 ensures that the clamp 12 can be stably locked at the target position after it is in place, and the position is reached as the trigger to prevent the limiting component 132 from locking in the wrong position and damaging the clamp 12. The aforementioned target position refers to the installation position of the clamp 12 on the clamp mounting base 13 when performing clamping work. In this embodiment, the above process is implemented by PLC control. Both the limiting component controller 133 and the position sensor 131 are connected to the PLC. In other embodiments, a robot controller integrated system can also be used. The signal of the position sensor 131 is connected to the general digital input of the robot control cabinet, and the output signal is sent out through the I / O board of the robot control cabinet to drive the limiting component controller 133. In this embodiment, the limiting member 132 is preferably a cylindrical limiting block, one end of which is inserted into the second limiting groove 123 and has a rounded chamfer. The other end of the rod is connected to the limiting member controller 133. In this embodiment, the limiting member controller 133 is a cylinder, and the cylindrical limiting block is fixedly connected to the moving end of the cylinder piston rod. In this embodiment, the sensing member 122 can be a metal object, and the corresponding position sensor 131 can be an inductive proximity switch. In some embodiments, the sensing member 122 can be a reflective surface, and the corresponding position sensor 131 can be a photoelectric sensor. The sensing member 122 can be directly installed on the circumferential side 121, or it can be installed on the circumferential side 121 through a mounting base. In addition, compared with the prior art using a rod-shaped connector to connect the arc plate and the moving plate, in this embodiment, the circumferential side 121 of the clamp 12 matches the shape of the mounting groove 134. The mounting groove 134 can directly provide positioning and certain support for the clamp 12, with a short torque, which makes the clamp 12 more stable and more accurate.

[0048] In this embodiment, the first limiting groove 1341 and the limiting protrusion 124 extending along the circumferential side 121 of the clamp 12 cooperate to bear the main load, and the limiting member 132 provides the holding force, making the clamp 12 more stable on the clamp mounting base 13 and ensuring the durability of the limiting member 132.

[0049] In this embodiment, the clamp 12 is designed as a semi-cylindrical shape, which is more adaptable than triangular, square, or other polygonal shapes. The robotic arm 2 can roughly position the clamp 12 on the clamp mounting base 13, as long as the circumferential side 121 of the clamp 12 fits against the mounting groove 134 and the limiting protrusion 124 engages with the first limiting groove 1341. Then, it is rotated in a predetermined direction and accurately positioned by the stop part 1211 being stopped by the limiting structure 1342, so that the angle of the clamp 12 is fixed. The sensor 122 triggers the position sensor 131, causing the limiter controller 133 to drive the limiter 132 to insert into the second limiter groove 123. This arrangement avoids the phenomenon that the actions of the sensor 122 triggering the position sensor 131 and the limiter controller 133 driving the limiter 132 cannot be completed due to a time difference. It allows the limiter 132 to be accurately and quickly inserted into the second limiter groove 123. It is known that during rotation, the limiter protrusion 124 moves simultaneously within the first limiter groove 1341. To ensure machining accuracy, the installation accuracy between the fixture 12 and the fixture 12 mounting plate needs to be very high, and the gap between them is small. If a rectangular or polygonal fixture 12 is used, it needs to be precisely positioned in one go, requiring high positioning accuracy. This would require an expensive robotic arm 2 to achieve this. In this embodiment, the semi-cylindrical fixture 12 allows the robotic arm 2 to achieve coarse positioning followed by fine positioning, which can be achieved without high configuration, reducing the purchase cost of the robotic arm 2. In addition, the arc-shaped circumferential side 121 can also avoid stress concentration when clamping pipe fittings, and extend the service life of the clamp 12 and the clamp mounting base 13.

[0050] In summary, this embodiment achieves fully automatic replacement of the clamp 12 through the cooperation of multiple parts of the clamp 12 and the clamp mounting base 13, improving work efficiency and still ensuring stable clamping of pipe fittings. Replacement can be completed with just one robotic arm 2, resulting in low automation upgrade costs.

[0051] refer to Figures 4-5In this embodiment, the fixture mounting base 13 is block-shaped. The lower half is a rectangular block with multiple mounting holes for fixed installation on the drive mechanism and sliding holding mechanism, such as on the slider, which is slidably connected to the slide rail on the mounting plate. The upper half is a trapezoidal block. The position sensor 131 is parallel to the upper plane of the trapezoid, i.e., parallel to the machine tool, and mounted on the side of the trapezoid. The corresponding sensing element 122 is located at the middle position of the circumferential side 121 of the fixture 12. The cylinder is mounted on the upper plane of the fixture mounting base 13 near the end of the fixture 12. The fixture mounting base 13 has a through hole that can communicate with the second limiting groove 123. The limiting element 132 is disposed in this through hole to allow the limiting element 132 to be inserted into or moved away from the second limiting groove 123. The above-mentioned reasonable position and shape settings make the position sensor 131 easy to install and also avoid the reduction of the load-bearing capacity of the fixture mounting base 13 due to the concentration of holes.

[0052] refer to Figure 3 In this embodiment and some other embodiments, when the clamp 12 rotates to the target position, the stop portion 1211 is located at the lower end of the circumferential side 121 of the clamp 12, and the second limiting groove 123 is located at the upper end of the circumferential side 121 of the clamp 12. The stop portion 1211 is stopped by the limiting structure 1342, which is closer to the inner circumferential side 125 than the stop portion 1211. This structure not only makes it convenient for the limiting member 132 to be accurately inserted into the second limiting groove 123, but also provides a stop on the lower side of the clamp 12, thus limiting both the upper and lower sides of the clamp 12, making it more stable.

[0053] refer to Figure 6 In this embodiment and some other embodiments, chamfers are provided at the connection points between the two sides of the limiting protrusion 124 and the circumferential side. The chamfers at the connection points between the two sides of the limiting protrusion 124 and the circumferential side allow the limiting protrusion 124 to slide into the first limiting groove 1341 even with a small offset. At this time, the robotic arm 2 can use a compliant mode. Alternatively, a passive compliant device can be added between the end flange and the gripper of the robotic arm 2, allowing for a slight offset of the end effector, so that the limiting protrusion 124 can successfully slide into the first limiting groove 1341. This further reduces the precision requirements of the robotic arm 2, and the basic robotic arm 2 can also have the aforementioned compliant mode and passive compliant device, meaning the purchase cost of the robotic arm 2 can be further reduced.

[0054] refer to Figure 7In this embodiment and some other embodiments, the limiting protrusion 124 has a notch at the lower end of the clamp 12, the stop portion 1211 is the end of the notch, and the limiting structure 1342 is a limiting pin corresponding to the notch and disposed at the lower end of the mounting groove 134. When the clamp 12 is in the target position, the limiting pin can abut against the end of the notch. The notch end serving as the stop portion 1211 can effectively utilize the space of the first limiting groove 1341 without interfering with other parts, making the entire device structure compact. In this embodiment, the upper end of the limiting protrusion 124 extends to the upper edge of the circumferential side 121, and the upper end of the limiting protrusion 124 is a plane. The second limiting groove 123 is disposed on the aforementioned plane. The plane setting facilitates the processing of the second limiting groove 123 and is beneficial to the visual recognition of the robotic arm to determine the installation direction of the clamp 12.

[0055] refer to Figure 4 In this embodiment and some other embodiments, a mounting base is fixedly installed on the circumferential side 121 of the clamp 12, and the sensor 122 is installed in the mounting base. A clearance groove 1343 is provided inside the first limiting groove 1341. When the clamp 12 rotates, the outer diameter and width of the clearance groove 1343 allow the mounting base and the sensor 122 to pass through. Specifically, the outer diameter of the clearance groove 1343 is larger than the maximum outer diameter of the clamp 12 on which the sensor 122 is mounted, but smaller than the outer diameter of the first limiting groove 1341. This ensures that the sensor 122 has sufficient travel space when the clamp 12 rotates.

[0056] refer to Figure 6 In this embodiment and some other embodiments, the clamp 12 has two through circular holes 126. The two circular holes 126 are symmetrically distributed with respect to the clamping groove 1251, so that the clamp 12 is subjected to uniform force when clamping the pipe, avoiding stress concentration, and at the same time, it can balance the cutting torque and suppress vibration. On the other hand, when the robotic arm 2 clamps a hole, the position of the jaw in the hole is not fixed, which causes the angle between the clamp 12 and the jaw of the robotic arm 2 to be inconsistent, making installation difficult. The two holes can fix the angle between the clamp 12 and the jaw of the robotic arm 2 when the robotic arm 2 clamps the clamp 12, which facilitates installation.

[0057] refer to Figures 8-9In this embodiment and some other embodiments, a base 4 is also included. A fixture assembly mounting plate 41 is fixedly installed at the front end of the base 4. The workpiece clamping device 1 is slidably installed on the fixture assembly mounting plate 41. A first driving mechanism 411 is fixedly installed on the fixture assembly mounting plate 41. The first driving mechanism 411 is used to drive two fixture mounting seats 13 to move closer or further away from each other perpendicular to the extension direction of the machine tool. The base 4 is slidably connected to the machine tool and can slide along the extension direction of the machine tool. A processing mechanism 42 for processing workpieces is also provided on the base 4. The processing mechanism 42 is slidably installed above the base 4. A second driving mechanism 43 is also fixed above the base 4. The second driving mechanism 43 is used to drive the processing mechanism 42 to slide relative to the base 4 along the extension direction of the machine tool. A stop mechanism 44 is also provided next to the processing mechanism 42. When the workpiece is installed into the workpiece clamping device 1, the stop arm 441 of the stop mechanism 44 can rotate to the space between the processing mechanism 42 and the workpiece clamping device 1. The distance between the stop arm 441 and the workpiece clamping device 1 can be adjusted by the third driving mechanism 45. The stop arm 441 determines the processing position of the workpiece by stopping the front end of the workpiece, controlling the front end of the pipe to be in the processing position. After the workpiece clamping device 1 clamps the workpiece, it retracts and rotates away from the processing mechanism 42 and the workpiece clamping device 1. The processing mechanism 42 moves closer to the workpiece clamping device 1 under the drive of the second drive mechanism 43 to realize the processing of the pipe. After processing, the processing mechanism 42 moves away from the workpiece clamping device 1 under the drive of the second drive mechanism 43. In this embodiment, the second drive mechanism 43 is a servo motor-lead screw mechanism. The front end of the lead screw is fixedly connected to the processing mechanism 42. The processing mechanism 42 is slidably connected to the base 4 through a slide rail. The servo motor-lead screw mechanism drives the processing mechanism 42 to slide relative to the base 4 along the extension direction of the machine table.

[0058] In this embodiment, the stop mechanism 44 has two parallel rods. One rod is hinged to the base 4 via a mounting seat. The two rods are connected by a connecting arm. The lower part of the connecting arm is hinged to the piston rod of a cylinder. The front ends of the two rods are fixed to a stop arm 441. The stop arm 441 is shaped to allow the stop mechanism 44 to rotate to the position in front of the workpiece without interference. When the piston rod of the cylinder moves upward, the rod hinged to the mounting seat rotates and its position is fixed. The connecting arm rotates upward, causing the stop arm 441 to rotate upward away from the position in front of the workpiece. When the piston rod of the cylinder moves downward, the rod hinged to the mounting seat rotates and its position is fixed. The connecting arm rotates downward, causing the stop arm 441 to rotate upward and move to the position in front of the workpiece. A third drive mechanism is also fixedly connected to the connecting arm. In this embodiment, the third drive mechanism is a cylinder. The cylinder is fixedly connected to the connecting arm, and the piston rod is fixedly connected to the stop arm 441, allowing the stop arm 441 to move back and forth to adjust the distance between it and the workpiece clamping device 1. In this embodiment, the first drive mechanism 411 is a motor-bidirectional lead screw mechanism. The bidirectional lead screw has two threaded segments with different helical directions. The two clamp mounting seats 13 are respectively threaded to the two threaded segments with different helical directions through clamping nut seats, so that the two can move closer to each other or further away from each other perpendicular to the extension direction of the machine tool. The clamp assembly mounting plate 41 also has two slide rails, which are respectively set on the upper and lower sides of the bidirectional lead screw. The two clamp mounting seats 13 are respectively fixedly mounted with upper and lower sliders, and the upper and lower sliders are slidably connected to the two slide rails, so that the movement of the clamp mounting seats 13 is more stable. The clamp mounting seats 13 have mounting holes for mounting fasteners that are fixedly connected to the sliders and clamping nut seats.

[0059] This embodiment also provides an automatic fixture changing system, including a robotic arm 2 for clamping mating parts, a tool magazine 3 for placing the fixture to be installed, and the workpiece clamping device described above.

[0060] refer to Figure 10In this embodiment and some other embodiments, the end gripper of the robotic arm 2 is a two-finger gripper, with each of the two gripping fingers 21 having a laterally protruding protrusion 211 at its end, and the two protrusions 211 being arranged in opposite directions. The two-finger gripper includes a finger cylinder 23 and two gripping blocks 22 mounted on the finger cylinder 23. Each gripping block 22 has a gripping finger 21 fixedly mounted or integrally formed on it. When the finger cylinder 23 drives the two gripping blocks 22 to move in opposite directions, the gripper opens to grip the clamp 12. When the two gripping blocks 22 move towards each other, the gripper releases the clamp 12, allowing it to exit from the hole. When the gripper grips the clamp 12, the two gripping fingers 21 extend into the two circular holes of the clamp 12 from the same direction, and both protrusions 211 extend to the other side of the circular holes. When the robotic arm 2 clamps the fixture 12 from the tool magazine 3, a large clamping force is required to prevent the fixture 12 from falling off. Laterally protruding protrusions 211 are provided at the ends of the two grippers so that when the robotic arm 2 clamps the fixture 12 from the tool magazine 3, the clamping force applied by the grippers to the fixture 12 can be reduced without causing the fixture 12 to fall off the robotic arm 2.

[0061] refer to Figure 11 In this embodiment and some other embodiments, the two-finger gripper is eccentrically arranged on the end rotating part 24 of the robotic arm 2. When the two-finger gripper clamps the clamp 12, it can rotate around the rotation axis of the clamp 12.

[0062] This embodiment also provides an automatic fixture changing method, including the following steps:

[0063] S1: The two clamp mounting seats 13 are driven to move away from each other, and the limit component controller 133 drives the limit component 132 to exit from the second limit groove 123; in this embodiment, the PLC sends a signal to control the limit component controller 133 to drive the limit component 132.

[0064] S2: The end-rotating part 24 of the robotic arm 2 is aligned with the center of the gripper 12;

[0065] S3: The gripper moves forward and clamps the clamp 12. After clamping, the end rotating part 24 of the robotic arm 2 rotates around the rotation axis of the clamp 12. After the clamp 12 is released from the limit, the robotic arm 2 is translated so that the robotic arm 2 removes the clamp 12 from the clamp mounting base 13 and places the clamp 12 into the corresponding position of the tool magazine 3.

[0066] The tool magazine can be disc type, hat type, linear type or synchronous type, etc. Each fixture has a unique address in the tool magazine. The tool magazine is equipped with a tool position sensor to ensure that the robotic arm accurately identifies the placement position of the fixture. In some embodiments, the robotic arm can also identify the fixture through visual recognition. In this embodiment, the robotic arm is controlled by PLC and CNC to complete the fixture replacement process.

[0067] S4: The robotic arm 2 picks up the fixture 12 to be replaced from the tool magazine 3;

[0068] S5: The robotic arm 2 moves the clamp 12 into the mounting groove 134. The robotic arm 2 moves the clamp 12 to the mounting groove 134. The robotic arm 2 translates so that the limiting protrusion 124 enters the first limiting groove 1341. The end rotating part 24 of the robotic arm 2 rotates around the rotation axis of the clamp 12, so that the clamp 12 rotates to the target position. After it is in place, the stop part 1211 on the clamp 12 is stopped by the limiting structure 1342.

[0069] S6: The sensing element 122 triggers the position sensor 131, causing the limit element controller 133 to drive the limit element 132 to be inserted into the second limit groove 123.

[0070] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A workpiece clamping device, characterized in that, Includes two clamp mounting bases (13) and two clamps (12); A position sensor (131), a limiting member (132), and a limiting member controller (133) are fixedly mounted on the fixture mounting base (13). The fixture (12) is semi-cylindrical. The fixture mounting base (13) has a semi-cylindrical mounting groove (134) that matches the shape of the circumferential side (121) of the fixture (12). The mounting groove (134) is provided with a first limiting groove (1341) and a limiting structure (1342). The fixture (12) is provided with a sensing element (122) corresponding to the position sensor (131), a second limiting groove (123) corresponding to the limiting member (132) on the circumferential side (121), a limiting protrusion (124) that matches the shape of the first limiting groove (1341), and a limiting structure. (1342) A stop portion (1211) that matches the outer peripheral contour, a limiting protrusion (124) extending along the circumferential side of the clamp (12) to form an arc-shaped flange, the clamp (12) is provided with a clamping groove (1251) for clamping the workpiece on the inner peripheral side (125), and at least two through circular holes (126) are provided between the two ends of the clamp (12). When the clamp (12) is in the target position, the limiting protrusion (124) is in the first limiting groove (1341), the limiting member (132) enters the second limiting groove (123) or is located above the second limiting groove (123), the sensing member (122) corresponds to the position sensor (131), and the stop portion (1211) is stopped by the limiting structure (1342); The mounting grooves (134) on the two clamps (12) are set opposite to each other. When a workpiece needs to be clamped, the two clamp mounting seats (13) are driven to move closer to each other, so that the two clamps (12) move closer to each other, and the workpiece is surrounded and clamped by the clamping grooves (1251) of the two clamps (12). When it is necessary to unload the workpiece or replace the clamps (12), the two clamp mounting seats (13) are driven to move away from each other.

2. The workpiece clamping device as described in claim 1, characterized in that, When the clamp (12) is in the target position, the stop (1211) is located at the lower end of the circumferential side (121) of the clamp (12), and the second limiting groove (123) is located at the upper end of the circumferential side (121) of the clamp (12). The stop (1211) is stopped by the limiting structure (1342), which is closer to the inner circumferential side (125) than the stop (1211).

3. The workpiece clamping device as described in claim 2, characterized in that, The limiting protrusion (124) has a notch at the lower end of the clamp (12), the stop part (1211) is the end of the notch, and the limiting structure (1342) is a limiting pin corresponding to the notch and disposed at the lower end of the mounting groove (134). When the clamp (12) is in the target position, the limiting pin can abut against the end of the notch.

4. The workpiece clamping device as described in claim 1, characterized in that, The clamp (12) has a mounting base fixedly installed on the circumferential side (121), and the sensor (122) is installed in the mounting base. The first limiting groove (1341) has a clearance groove (1343) inside. When the clamp (12) rotates, the outer diameter and width of the clearance groove (1343) allow the mounting base and the sensor (122) to pass through.

5. The workpiece clamping device as described in claim 1, characterized in that, The clamp (12) has two through circular holes (126) between its two ends, and the two circular holes (126) are symmetrically distributed relative to the clamping groove (1251).

6. The workpiece clamping device as described in claim 1, characterized in that, It also includes a base (4), on which a fixture assembly mounting plate (41) is fixedly mounted. Two fixture mounting seats (13) are slidably mounted on the fixture assembly mounting plate (41). A first drive mechanism (411) is fixedly mounted on the fixture assembly mounting plate (41). The first drive mechanism (411) is used to drive the two fixture mounting seats (13) to move closer to or further away from each other perpendicular to the extension direction of the machine tool. The base (4) is slidably connected to the machine tool and can slide along the extension direction of the machine tool. A processing mechanism (42) for processing workpieces is also provided on the base (4). The processing mechanism (42) is slidably mounted above the base (4). A fixture is also fixed above the base (4). The second drive mechanism (43) is used to drive the processing mechanism (42) to slide relative to the base (4) along the extension direction of the machine tool. A stop mechanism (44) is also provided next to the processing mechanism (42). When the workpiece is installed in the fixture (12), the stop arm (441) of the stop mechanism (44) can rotate between the processing mechanism (42) and the fixture (12) to determine the processing position of the workpiece by stopping the front end of the workpiece. After the fixture (12) clamps the workpiece, it rotates away from the processing mechanism (42) and the fixture (12). The stop arm (441) can adjust the distance between itself and the fixture (12) through the third drive mechanism (45).

7. An automatic fixture changing system, comprising a robotic arm (2) for clamping mating parts, a tool magazine (3) for placing fixtures to be installed, and a workpiece clamping device as claimed in any one of claims 1-6.

8. The automatic clamp changing system as described in claim 7, characterized in that, The end gripper of the robotic arm (2) is a two-finger gripper. The ends of the two grippers (21) each have a laterally protruding protrusion (211). The two protrusions (211) are arranged in opposite directions. When the gripper opens to hold the clamp (12), the two grippers (21) extend into the two round holes of the clamp (12) from the same direction, and the two protrusions (211) extend to the other side of the round hole.

9. The automatic clamp changing system as described in claim 8, characterized in that, The two-finger gripper is eccentrically positioned on the end rotating part (24) of the robotic arm (2). When the two-finger gripper clamps the clamp (12), it can rotate around the rotation axis of the clamp (12).

10. An automatic fixture changing method, applied to an automatic fixture changing system as described in any one of claims 7-9, characterized in that, Includes the following steps: S1: The two clamp mounting seats (13) are driven to move away from each other, and the limit component controller (133) drives the limit component (132) to exit from the second limit groove (123); S2: The end-rotating part (24) of the robotic arm (2) is aligned with the center of the clamp (12); S3: The gripper moves forward and clamps the fixture (12). After clamping, the end rotating part (24) of the robotic arm (2) rotates around the rotation axis of the fixture (12). After the fixture (12) is released from its limit, the robotic arm (2) is translated so that the robotic arm (2) removes the fixture (12) from the fixture mounting base (13) and places the fixture (12) into the corresponding position of the tool magazine (3). S4: The robotic arm (2) picks up the fixture (12) to be replaced from the tool magazine (3); S5: The robotic arm (2) moves the clamp (12) to the mounting groove (134), and the robotic arm (2) is translated so that the limiting protrusion (124) enters the first limiting groove (1341). The end rotating part (24) of the robotic arm (2) rotates around the rotation axis of the clamp (12) so that the clamp (12) rotates to the target position. After it is in place, the stop part (1211) on the clamp (12) is stopped by the limiting structure (1342). S6: The sensing element (122) triggers the position sensor (131), causing the limiter controller (133) to drive the limiter (132) to be inserted into the second limiter groove (123).

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