Numerical control machining center clamp quick change device

Abstract

The numerical control machining center clamp quick change device disclosed by the application comprises an off-machine pre-adjustment platform, a guide rail, a front and rear push-pull platform, an up and down lifting tray, a front and rear driving mechanism, a lifting driving mechanism, an anti-falling mechanism and an electric control box. The off-machine pre-adjustment platform is provided with a positioning mechanism. The front and rear push-pull platform is slidingly arranged on the guide rail. The up and down lifting tray is arranged on the front and rear push-pull platform. The front and rear driving mechanism is installed on the off-machine pre-adjustment platform and connected with the output end of the front and rear push-pull platform. The lifting driving mechanism is installed on the front and rear push-pull platform and connected with the output end of the up and down lifting tray. The anti-falling mechanism is installed on the front and rear push-pull platform. The device can improve the clamp replacement efficiency, eliminate safety hazards, ensure the installation precision and stability and support flexible production, and is especially suitable for the working condition that the utilization rate of the machine tool is seriously insufficient due to the heavy and large special clamp when large integrated die-casting front cabin and rear floor parts are machined on a high-speed double five-axis gantry machining center.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool tooling fixture technology, specifically relating to a quick-change device for CNC machining center fixtures, used for quickly changing heavy-duty fixtures of CNC machining centers, especially suitable for use with high-speed dual five-axis gantry machining centers when machining large integrated die-cast structural parts. Background Technology

[0002] With the rapid development of the new energy vehicle market, large-scale integrated die-cast parts such as the front cabin and rear floor have become the mainstream trend. These parts often have a projected area greater than 2 square meters, are huge in size, have complex structures, and have machining features distributed on multiple surfaces, placing extremely high demands on the clamping efficiency and precision of machining equipment. Conventional machine tools require multiple clamping operations to complete the precision machining of all features of such parts, making it difficult to balance clamping efficiency and machining accuracy.

[0003] High-speed dual five-axis gantry machining centers, with their high rigidity, high dynamic response, high rapid traverse speed, and ability to complete the machining of six-sided structures in a single setup, have become the preferred equipment for machining such parts. However, the special fixtures required for machining these parts are usually bulky, complex in structure, and can weigh over 1000 kg. Traditional fixture changeover methods primarily rely on overhead cranes or bridge cranes for hoisting. This method has numerous drawbacks: 1) Extremely low efficiency: Hoisting, rough alignment, fine leveling, and multi-part locking are cumbersome steps that consume all machine tool processing time, with a single changeover taking up to 4 hours; 2) High safety risks: Heavy fixtures are hoisted at heights and in blind spots within the confined space of the machine tool, posing a significant risk of collision with the machine tool spindle, tool magazine, and safety doors, potentially causing damage to equipment worth millions or even tens of millions of dollars; 3) Difficulty in guaranteeing positioning accuracy: Fixture positioning relies on repeated dial-up calibration based on operator experience, resulting in poor repeatability and difficulty in ensuring batch consistency, leading to a high scrap rate for the first piece; 4) Consumption of production space: Large hoisting equipment requires a spacious operating area; 5) Poor production flexibility: Heavy hoisting operations make rapid changeovers difficult, hindering production lines from responding to the flexible production demands of multi-variety, small-batch production. These factors severely restrict the capacity release and return on investment of high-end machine tools. While some existing technologies have attempted to improve fixture changing efficiency by using external supports and horizontal sliding, their support frames are one-piece structures, which suffer from insufficient support rigidity and limited drive stroke in heavy-duty, long-stroke scenarios. Furthermore, they lack complete safety redundancy and automated control systems. Therefore, there is an urgent need for a device that can safely, efficiently, and accurately achieve rapid changeover of heavy-duty fixtures. Summary of the Invention

[0004] To address the problems of low efficiency, safety hazards, poor positioning accuracy, and insufficient adaptability to multi-product co-production of traditional fixtures, this invention provides a quick-change fixture device for CNC machining centers. It is particularly suitable for situations where the machine tool utilization rate is severely insufficient due to the heavy and bulky special fixtures when machining large integrated die-casting front chambers, rear floors, and other parts on high-speed dual five-axis gantry machining centers.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a quick-change device for CNC machining center fixtures, comprising an external pre-adjustment platform, a guide rail, a front and rear push-pull platform, an upper and lower lifting tray, a front and rear drive mechanism, a lifting drive mechanism, an anti-fall-off mechanism, and an electrical control box. The external pre-adjustment platform is equipped with a positioning mechanism for docking with the CNC machining center. The guide rail includes an external guide rail and an internal guide rail. The external guide rail is installed on the external pre-adjustment platform, and the internal guide rail is installed inside the machine tool. The internal guide rail is located at a corresponding extension position of the external guide rail. The front and rear push-pull platform is slidably disposed on the guide rail. The upper and lower lifting tray is equipped with... The upper and lower lifting trays are placed on the front and rear push-pull platforms and are used to carry the clamps. The front and rear drive mechanisms are installed on the external pre-adjustment platform and the output end of the front and rear drive mechanisms is connected to the front and rear push-pull platforms. The front and rear drive mechanisms are used to drive the front and rear push-pull platforms to slide along the guide rail. The lifting drive mechanism is installed on the front and rear push-pull platforms and the output end of the lifting drive mechanism is connected to the upper and lower lifting trays. The anti-drop mechanism is installed on the front and rear push-pull platforms and is used to lock the upper and lower lifting trays when they are in the raised position. The electrical control box is used to control the actions of the front and rear drive mechanisms, the lifting drive mechanism, and the anti-drop mechanism.

[0006] The working process of the quick-change device of the present invention is as follows: First, move the external pre-adjustment platform to the vicinity of the CNC machining center. The positioning mechanism on the external pre-adjustment platform docks and locks the entire device with the CNC machining center. At this point, the CNC machining center can operate normally without affecting its production efficiency. After the machine tool completes the machining of the last workpiece, the operator initiates the mold-changing program through the electrical control box, and the machine door opens. At this time, the upper and lower lifting pallets are in the lowered position. The electrical control box controls the front and rear drive mechanisms according to the set control logic. The output of the front and rear drive mechanisms drives the front and rear push-pull platforms to slide along the guide rail from the external pre-adjustment platform towards the inside of the machine tool, transporting the upper and lower lifting pallets and the old fixture they carry on the external pre-adjustment platform to the predetermined position inside the machine tool. After reaching the predetermined position, the front and rear drive mechanisms stop, the automatic fixture locking mechanism inside the machine tool releases the old fixture, and the electrical control box controls the lifting drive mechanism to operate. The output of the lifting drive mechanism drives the upper and lower lifting pallets to rise, lifting the old fixture upwards to disengage it from the positioning pin on the machine tool's worktable, and continuing to rise to the preset safe height, thus completely detaching the old fixture from the machine tool. The anti-drop mechanism then activates to lock the upper and lower lifting trays in the raised position, preventing the trays from falling due to accidental loss of air supply. Subsequently, the electrical control box controls the front and rear drive mechanisms to move in the opposite direction, driving the front and rear push-pull platforms back along the guide rails to the initial position on the external pre-adjustment platform. At this time, the old fixture is transported to the outside of the machine tool along with the upper and lower lifting trays.

[0007] On the external pre-adjustment platform, the operator removes the old fixture from the upper and lower lifting trays and places the new fixture to be installed on them. The positioning structure on the upper and lower lifting trays initially aligns the new fixture. After the new fixture is placed, the anti-drop mechanism releases the locking mechanism on the upper and lower lifting trays. The control box then controls the front and rear drive mechanisms to operate again, driving the front and rear push-pull platforms along the guide rails to transport the upper and lower lifting trays and the new fixture they carry to the predetermined position inside the machine tool. Once the predetermined position is reached, the control box controls the lifting drive mechanism to reverse, driving the upper and lower lifting trays to descend, allowing the new fixture to gradually land on the machine tool's worktable and achieve precise docking through the positioning pins on the worktable. After the new fixture is fully in place, the machine tool's internal automatic fixture locking mechanism locks and secures the new fixture. The control box then controls the front and rear drive mechanisms to reverse again, driving the front and rear push-pull platforms along the guide rails back to the initial position on the external pre-adjustment platform, completely disengaging the upper and lower lifting trays from the new fixture. The fixture replacement process is now complete. The machine tool door is closed, and the operator can begin a trial cut to verify the new fixture's installation accuracy. Once the accuracy of the new fixture is confirmed to be satisfactory, batch processing can begin. Throughout the entire mold change process, the front and rear push-pull platforms slide along the guide rails to ensure the accuracy of the heavy-duty fixture's reciprocating movement between the machine and the external machine tool, as well as its smooth operation.

[0008] This invention's quick-change device achieves rapid and precise docking between the entire device and the CNC machining center through a positioning mechanism on an external pre-adjustment platform, eliminating the need for repeated dial gauge calibration inside the machine tool. The front and rear push-pull platforms slide along guide rails to ensure smooth transport of the fixture between the machine tool and the external environment. The upper and lower lifting pallets, via a lifting drive mechanism, detach and dock the fixture from the machine tool's worktable. The front and rear drive mechanisms provide long-stroke, heavy-duty propulsion power. An anti-drop mechanism locks the lifting pallets in the rising position to prevent accidental descent and damage. The electrical control box controls the timing of each actuator according to a predetermined program, thereby transferring the heavy fixture replacement operation from inside the machine tool to outside, significantly reducing machine tool downtime, eliminating safety hazards associated with high-altitude hoisting, and ensuring consistent installation accuracy after each fixture replacement through the pre-adjustment positioning structure.

[0009] Preferably, the external guide rails include an external left guide rail and an external right guide rail, and the internal guide rails include an internal left guide rail and an internal right guide rail. The external left guide rail corresponds to the internal left guide rail, and the external right guide rail corresponds to the internal right guide rail. External limit stops are provided on the external left and external right guide rails, and internal limit stops are provided on the internal left and internal right guide rails. By setting the external and internal guide rails as symmetrical double-rail structures, double-sided support and guidance are provided for the front and rear push-pull platforms, ensuring balanced force and smooth operation of the heavy-duty fixture during long-stroke advancement. Limit stops are provided on the external and internal guide rails to limit the sliding limit positions of the front and rear push-pull platforms, preventing the push-pull platforms from exceeding the safe stroke range and colliding with the internal structure of the machine tool, thus ensuring the positional accuracy and operational safety of the push-pull mechanism's reciprocating motion.

[0010] Preferably, the guide rails are equipped with a plurality of precision cam bearings, which are respectively installed in the horizontal and vertical directions of the outer left and outer right guide rails. By installing precision cam bearings in the horizontal and vertical directions of the outer left and outer right guide rails, multi-directional rolling contact is formed between the front and rear push-pull platforms and the guide rails, converting sliding friction into rolling friction, reducing the movement resistance of the push-pull platforms, ensuring the smooth movement and directional parallelism of the heavy-duty fixture during long-stroke propulsion, and avoiding skewing and jamming caused by heavy loads. In the initial state, the contact surfaces of the precision cam bearings and the front and rear push-pull platforms maintain a predetermined distance. During propulsion, the precision cam bearings automatically adjust to a close-fitting state according to the force applied, ensuring the parallelism and smooth operation of the front and rear push-pull platforms during long-stroke heavy-load propulsion.

[0011] Preferably, the front and rear drive mechanism includes a primary rod cylinder and a secondary rodless cylinder, which are connected by a hinge structure. The output end of the secondary rodless cylinder is connected to the front and rear push-pull platforms. This two-stage drive mechanism, consisting of a primary rod cylinder and a secondary rodless cylinder connected by a hinge structure, enables large-stroke push-pull movements within a limited installation space. The primary rod cylinder provides the initial driving force, while the secondary rodless cylinder provides the long-stroke output. The output end of the secondary rodless cylinder is directly connected to the front and rear push-pull platforms to drive their reciprocating sliding. The overall structure is compact, reducing the footprint and manufacturing cost of the quick-change fixture device.

[0012] Preferably, the lifting drive mechanism includes four lifting cylinders, which are respectively installed at the four corners of the front and rear push-pull platforms. The piston rod of each lifting cylinder is connected to the upper and lower lifting trays. Guide rods are provided at the four corners of the front and rear push-pull platforms, and guide sleeves are correspondingly provided on the upper and lower lifting trays. The guide rods and guide sleeves are slidably engaged. By installing four lifting cylinders at the four corners of the front and rear push-pull platforms, the piston rods of each lifting cylinder simultaneously drive the upper and lower lifting trays to rise and fall, ensuring that the trays are evenly stressed and move smoothly during the lifting process, avoiding jamming due to uneven load. The guide rods at the four corners of the front and rear push-pull platforms and the guide sleeves at corresponding positions on the upper and lower lifting trays, with the guide rods and guide sleeves slidably engaged, precisely guide the lifting movement, ensuring that the upper and lower lifting trays always maintain a horizontal posture during the lifting process, thereby achieving precise docking between the fixture and the positioning pins on the machine tool worktable.

[0013] Preferably, the anti-falling mechanism includes a left pin, a right pin, and a left cylinder and a right cylinder respectively driving the left pin and the right pin. The left pin and the right pin are installed on the front and rear push-pull platform. When the upper and lower lifting trays rise to their highest position, the left pin and the right pin extend and are positioned below the upper and lower lifting trays. By installing the left pin and the right pin on the front and rear push-pull platform, and driving them to extend and retract by the left cylinder and the right cylinder respectively, when the upper and lower lifting trays rise to their highest position, the left and right pins extend simultaneously and are positioned below the upper and lower lifting trays, forming a mechanical blockage on the trays from both sides. Even if the air supply to the lifting cylinders is accidentally lost, the upper and lower lifting trays will not suddenly fall, providing a reliable safety guarantee for off-machine replacement operations of heavy-duty clamps.

[0014] Preferably, the positioning mechanism is located at the bottom of the external pre-adjustment platform. The positioning mechanism includes liftable rollers, a coarse positioning guide mechanism, a connecting bracket, a positioning bracket, and a locking bracket. The coarse positioning guide mechanism cooperates with the coarse positioning guide rod on the machine tool. The connecting bracket and the positioning bracket contact the limiting surface of the machine tool to achieve positioning. The locking bracket locks the external pre-adjustment platform to the machine tool. By providing liftable rollers at the bottom of the external pre-adjustment platform, the entire device can be flexibly moved to the vicinity of the machine tool and adjusted to a suitable height. The coarse positioning guide mechanism cooperates with the coarse positioning guide rod on the machine tool to achieve initial alignment between the device and the machine tool. Precise positioning is then achieved by the connecting bracket and the positioning bracket contacting the limiting surface of the machine tool. The locking bracket locks the external pre-adjustment platform to the machine tool to prevent displacement during operation, thereby ensuring the repeatability of the quick-change fixture's position and the rigidity of its installation each time it docks with the machine tool.

[0015] Preferably, the quick-change device of the present invention further includes a detection system, which includes a rear limit switch, a front limit switch, a lower limit switch, an upper limit switch, a proximity switch, and a clamp positioning limit switch. The rear limit switch is used to detect the return positioning signal of the front and rear push-pull platforms; the front limit switch is used to detect the advance positioning signal of the front and rear push-pull platforms; the lower limit switch is used to detect the descent positioning signal of the upper and lower lifting trays; the upper limit switch is used to detect the descent positioning signal of the upper and lower lifting trays; the proximity switch is used to detect the extension and retraction status of the anti-drop mechanism; and the clamp positioning limit switch is used to detect whether the clamp is in position. These switches constitute a complete closed-loop detection network, feeding back the real-time position and status signals of each actuator to the control box, ensuring that each mechanism operates according to the predetermined sequence, and avoiding equipment collisions and personnel injuries caused by incorrect position or status.

[0016] Preferably, the upper and lower lifting pallets are provided with a conical guide structure, the diameter of which is smaller than the diameter of the positioning hole at the bottom of the clamp; the front and rear push-pull platforms are provided with a coarse guide device, which is used for initial guidance when the clamp is placed on the upper and lower lifting pallets. By providing a conical guide structure on the upper and lower lifting pallets, and making the diameter of the positioning pin smaller than the diameter of the positioning hole at the bottom of the clamp, the clamp is first coarsely guided by the gap between the positioning pin and the positioning hole during the placement process, and then the conical surface gradually guides the clamp to the precise position. This avoids jamming or damage to the positioning pin caused by directly pressing in an excessively heavy clamp. At the same time, the coarse guide device on the front and rear push-pull platforms, used for initial guidance when the clamp is placed on the upper and lower lifting pallets, forms a two-stage guidance system from coarse to fine with the conical guide structure, ensuring the smooth placement and precise positioning of the heavy clamp on the upper and lower lifting pallets.

[0017] Preferably, the electrical control box communicates with the electrical cabinet of the CNC machining center via quick-connect connectors for point-to-point I / O communication.

[0018] Compared with the prior art, the present invention has the following advantages: 1. Improve fixture change efficiency: Fixture change operations can be carried out in parallel with machine tool processing through an external pre-adjustment platform. The front and rear drive mechanisms, together with the guide rails, transport the new fixture that has been clamped to the machine tool as a whole. There is no need to lift, rough alignment, fine adjustment and leveling and locking of multiple parts inside the machine tool. The changeover time is reduced from several hours to less than twenty minutes, shortening the machine tool downtime and greatly improving the capacity utilization rate (OEE) of the high-speed machining center, thus greatly increasing the return on investment.

[0019] 2. Eliminate safety hazards: The loading, unloading and transfer of fixtures are all completed on the pre-adjusted platform outside the machine. The front and rear drive mechanisms automatically feed the fixtures into and out of the machine tool according to the control program of the electrical control box. Operators can work outside the machine tool without having to enter the machine tool for high-altitude or blind-spot operations, realizing automated operation with separation of man and machine. This meets the safety standards of intelligent manufacturing and can prevent heavy fixtures from colliding with the machine tool spindle, tool magazine, protective door and other components during hoisting.

[0020] 3. Ensure the installation accuracy and stability of the fixture: The positioning mechanism on the external pre-adjustment platform enables the device to be repeatedly positioned with the machine tool. The front and rear push-pull platforms slide along the guide rail to maintain the straightness of the conveying direction. The lifting drive mechanism drives the upper and lower lifting trays to place the fixture on the machine tool worktable. Compared with the clamping method of manual calibration, the installation positioning accuracy of this device is guaranteed by mechanical guidance and positioning structure, and is not affected by the difference in operator experience. The repeatability positioning accuracy is consistent.

[0021] 4. Supports Flexible Production: The upper and lower lifting pallets are used to support the fixtures. Specialized fixtures for different parts can be placed on the same upper and lower lifting pallets. During production changeovers, only the fixture itself needs to be replaced, allowing for rapid switching of fixtures for different parts. Combined with MES system scheduling, this enables large-scale customized flexible production. This invention is particularly suitable for situations where the machine tool utilization rate is severely insufficient due to the heavy and bulky specialized fixtures when machining large integrated die-casting parts such as front compartments and rear floors on high-speed dual five-axis gantry machining centers. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing the usage state of the quick-change fixture device in the embodiment; Figure 2 This is a bottom view of the external pre-adjustment platform in the embodiment; Figure 3 This is a schematic diagram of the moving part in the embodiment; Figure 4 This is a schematic diagram of the installation of the detection system in the embodiment. Figure 1 ; Figure 5 This is a schematic diagram of the installation of the detection system in the embodiment. Figure 2 ; The specific reference numerals in the figure are as follows: 1-Base, 2-Liftable rollers, 3-Coarse positioning guide mechanism, 4-External left guide rail, 5-External right guide rail, 6-Front and rear push-pull platform, 7-Up and down lifting tray, 8-Internal left guide rail, 9-Internal right guide rail, 10-First-stage rod-mounted cylinder, 11-Second-stage rodless cylinder, 12-Lifting cylinder, 13-Left side pin, 14-Right side pin, 15-Left side cylinder, 16-Right side cylinder, 17-Coarse positioning guide rod, 18, 19-Connecting bracket, 20-Positioning 21-Locking bracket, 22-Guide rod, 23, 24-Rough guide device, 25-Conical guide structure, 26, 27-External limit stop, 28, 29-Internal limit stop, 30-Electrical control box, 31-Machine tool, 32-Clamp, 33-Workpiece, A1, A2-Rear limit switch, B1, B2-Front limit switch, C1, C2-Lower limit switch, D1, D2-Upper limit switch, E1, E2, F1, F2-Proximity switch, H1, H2-Clamping position limit switch. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Components or structures not limited in this invention are all constructed using conventional techniques in the art.

[0024] like Figure 1 As shown, the quick-change fixture device for CNC machining centers includes an external pre-adjustment platform, guide rails, front and rear push-pull platforms 6, upper and lower lifting trays 7, front and rear drive mechanisms, lifting drive mechanisms, anti-fall-off mechanisms, an electrical control box 30, and a detection system. The external pre-adjustment platform is equipped with a positioning mechanism for docking with the CNC machining center.

[0025] The external pre-adjustment platform is a movable structure, with liftable casters 2 installed at the bottom of its base 1, allowing the entire device to be moved to the machine tool 31. Figure 1 The machine tool 31 is a simplified schematic diagram of the machine tool, 32 is the fixture, and 33 is the workpiece. The workpiece is positioned near the machine tool 31 and adjusted to a suitable height. A coarse positioning guide mechanism 3 is installed under the base 1. External left guide rail 4 and external right guide rail 5 are installed on the worktable of the base 1. Internal left guide rail 8 and internal right guide rail 9 are installed at corresponding positions inside the machine tool 31. Internal left guide rail 8 is located at the corresponding extension position of external left guide rail 4, and internal right guide rail 9 is located at the corresponding extension position of external right guide rail 5. The external guide rails and internal guide rails together constitute the guide rails.

[0026] The front and rear push-pull platforms 6 are slidably mounted on guide rails. Several precision cam bearings are installed on the guide rails, positioned horizontally and vertically on the outer left guide rail 4 and outer right guide rail 5, respectively. Initially, they maintain a 1mm gap on each side of the contact surface with the front and rear push-pull platforms 6. During the pushing process, the cam bearings automatically adjust to a close contact state based on the applied force. The front and rear end faces of the front and rear push-pull platforms 6 have chamfers in the horizontal and vertical directions to ensure parallelism and smooth movement during the pushing process. An external limit stop 26 is installed on the outer left guide rail 4, an external limit stop 27 is installed on the outer right guide rail 5, an internal limit stop 28 is installed on the inner left guide rail 8, and an internal limit stop 29 is installed on the inner right guide rail 9, all used to limit the sliding limit positions of the front and rear push-pull platforms 6.

[0027] A lifting tray 7 is installed on the front and rear push-pull platform 6. Guide rods 22 are installed at the four corners of the front and rear push-pull platform 6, and self-lubricating guide sleeves are installed at the corresponding positions of the lifting tray 7. The guide rods 22 and the guide sleeves slide together to ensure the parallelism and smooth operation of the lifting tray 7 during the lifting process.

[0028] The front and rear drive mechanism is mounted on an external pre-adjustment platform and is used to drive the front and rear push-pull platforms 6 to slide along the guide rail. The front and rear drive mechanism includes a primary rod cylinder 10 and a secondary rodless cylinder 11. The primary rod cylinder 10 and the secondary rodless cylinder 11 are connected by a hinge structure, which realizes the series transmission of the two-stage driving force. The output end of the secondary rodless cylinder 11 is connected to the front and rear push-pull platforms 6. The primary rod cylinder 10 is mounted on the base 1, and the secondary rodless cylinder 11 is connected to the front and rear push-pull platforms 6 to form the front and rear push-pull mechanism.

[0029] The lifting drive mechanism is installed on the front and rear push-pull platforms 6. The output end of the lifting drive mechanism is connected to the upper and lower lifting trays 7, and is used to drive the upper and lower lifting trays 7 to rise or fall. The lifting drive mechanism includes four lifting cylinders 12, which are respectively installed at the four corners of the front and rear push-pull platforms 6. The piston rod of each lifting cylinder 12 is connected to the upper and lower lifting trays 7.

[0030] An anti-drop mechanism is installed on the front and rear push-pull platforms 6 to lock the upper and lower lifting tray 7 in the raised position. The anti-drop mechanism includes a left pin 13, a right pin 14, and a left cylinder 15 and a right cylinder 16 that drive the left pin 13 and right pin 14 respectively. The left pin 13 and right pin 14 are installed on the front and rear push-pull platforms 6. When the upper and lower lifting tray 7 rises to its highest position, the left pin 13 and right pin 14 extend and are positioned below the upper and lower lifting tray 7 to prevent accidental descent and damage to the tray.

[0031] The aforementioned front and rear push-pull platforms 6, upper and lower lifting trays 7, front and rear drive mechanisms, lifting drive mechanisms, and anti-fall-off mechanisms together constitute the moving part, and its structural diagram is shown below. Figure 3 The moving part can slide along the guide rail as a whole, driven by a front and rear drive mechanism, and the upper and lower lifting tray 7 can be raised and lowered relative to the front and rear push-pull platform 6 by a lifting drive mechanism.

[0032] The lifting tray 7 is equipped with a conical guide structure 25. The diameter of the locating pin of the conical guide structure 25 is smaller than the diameter of the locating hole at the bottom of the fixture. Specifically, the diameter of the pin on the conical guide structure 25 is 2mm smaller than the opening on the fixture, leaving this margin for coarse guidance adjustment when the tray rises to align with the old fixture, the new fixture is lowered, and the machine tool 31 is positioned. The axial height of the conical guide structure 25 is configured such that before the fixture and the locating pin on the machine tool worktable complete the fine positioning, the conical guide structure 25 maintains a clearance fit with the locating hole at the bottom of the fixture. It only works together with the machine tool locating pin in the final stage of fixture descent, avoiding interference and jamming of multiple guide mechanisms before fine positioning. The front and rear push-pull platforms 6 are equipped with coarse guide devices 23 and 24, which are installed on the left and right sides of the front and rear push-pull platforms 6 respectively. The coarse guide devices 23 and 24 are equipped with large inclined surface structures, which are used for the initial guidance when the clamp is placed on the upper and lower lifting trays 7. After the new clamp is placed on it, it is gradually guided by the large inclined surface structure, and then it is placed on the tray by the conical guide structures 25 at the four corners of the upper and lower lifting trays 7.

[0033] The electrical control box 30 is installed on the side of the quick-change fixture device, integrating control signals and electro-pneumatic valves to control the operation of the front and rear drive mechanisms, lifting drive mechanism, and anti-drop mechanism. The electrical control box 30 communicates point-to-point with the electrical cabinet of the CNC machining center via quick-connect connectors, enabling the installation and removal of the quick-change fixture device without power interruption. The electrical control box 30 integrates an emergency stop button, an enable button, and an automatic run button to ensure the safety of quick-change operations. A secondary development interface for the quick-change fixture is provided on the CNC system interface, allowing for single-step operation and debugging of quick-change fixtures via the system's touchscreen.

[0034] The detection system includes rear limit switches A1 and A2, front limit switches B1 and B2, lower limit switches C1 and C2, upper limit switches D1 and D2, proximity switches E1, E2, F1 and F2, and fixture positioning limit switches H1 and H2. Rear limit switches A1 and A2 are installed on the rear side of the external pre-adjustment platform to detect the return signal of the front and rear push-pull platforms; front limit switches B1 and B2 are installed on the front side of the external pre-adjustment platform to detect the advance signal of the front and rear push-pull platforms; lower limit switches C1 and C2 are installed between the front and rear push-pull platforms and the upper and lower lifting trays to detect the signal of the upper and lower lifting trays descending to the lowest position; upper limit switches D1 and D2 are installed between the front and rear push-pull platforms and the upper and lower lifting trays to detect the signal of the upper and lower lifting trays rising to the highest position; proximity switches E1, E2, F1, and F2 are installed on the left and right sides of the front and rear push-pull platforms to detect the extension and retraction status of the anti-drop mechanism; clamp positioning limit switches H1 and H2 are installed on the upper and lower lifting trays to detect whether the clamp is in position.

[0035] The installation process of the above-mentioned quick-change fixture is as follows: Before changing the mold on the machine tool 31, the entire device is moved outside the machine tool 31. It is then pushed towards the machine tool 31 along the coarse positioning guide rod 17 installed on the machine tool 31 via the coarse positioning guide mechanism 3 under the base 1, until it reaches the bottom and contacts the limiting surfaces of the machine tool connecting brackets 18 and 19. Precise positioning is achieved through the positioning surface on the right side of the base 1 and the positioning bracket 20. The height is adjusted using the liftable rollers 2 and the connecting brackets 18 and 19, and the mounting screws are tightened. Finally, the locking bracket 21 is used to lock the quick-change device onto the machine tool 31, completing the precise docking with the machine tool 31.

[0036] The working process of the above-mentioned quick-change fixture is as follows: Before changing the mold for production, the entire quick change device is moved outside the machine tool 31 via the liftable roller 2 and precisely docked with the machine tool 31. At this time, the machine tool 31 can still process normally.

[0037] When machine tool 31 completes its final machining program and the fixture is changed, the machine tool door opens. The electrical control box 30 controls the front and rear drive mechanisms: the primary rod-driven cylinder 10 and the secondary rodless cylinder 11 drive the front and rear push-pull platforms 6 and the upper and lower lifting trays 7 into the machine tool 31. Once in position, the machine tool 31's built-in fixture automatic locking mechanism releases, and the electrical control box 30 controls the lifting drive mechanism: four lifting cylinders 12 drive the upper and lower lifting trays 7 upwards, disengaging the old fixture from the machine tool 31 and raising it above the fixture positioning pins of the machine tool 31. At this time, the detection system sends a signal confirming that the upper and lower lifting trays 7 have reached their highest position. The electrical control box 30 then controls the anti-fall mechanism: the left cylinder 15 and the right cylinder 16 respectively drive the left pin 13 and the right pin 14 to extend and position themselves below the upper and lower lifting trays 7, preventing accidental descent and damage to the trays.

[0038] After confirming the anti-drop mechanism is locked, the electrical control box 30 controls the front and rear drive mechanisms: the first-stage rod cylinder 10 and the second-stage rodless cylinder 11 drive the front and rear push-pull platforms 6 and the upper and lower lifting trays 7, and the old fixture returns to the outside of the machine tool 31. While keeping the upper and lower lifting trays 7 raised, the operator uses a crane to safely remove the old fixture. When the new fixture is placed on the upper and lower lifting trays 7, it is initially guided by the coarse guide devices 23 and 24 on both sides of the front and rear push-pull platforms 6. The large inclined surface structure on the coarse guide devices 23 and 24 gradually guides the fixture to the top of the upper and lower lifting trays 7. Then, the conical guide structures 25 at the four corners of the upper and lower lifting trays 7 complete the fine positioning. After the positioning pins of the conical guide structures 25 enter the positioning holes at the bottom of the fixture, a 2mm clearance is used to guide the fixture to the precise position.

[0039] After the new fixture is placed, the anti-drop mechanism is unlocked: the left cylinder 15 and the right cylinder 16 drive the left pin 13 and the right pin 14 to retract, respectively. The electrical control box 30 controls the front and rear drive mechanism: the first-stage rod cylinder 10 and the second-stage rodless cylinder 11 drive the front and rear push-pull platform 6 and the upper and lower lifting tray 7, and the new fixture enters the machine tool 31. After it is in place, the electrical control box 30 controls the lifting drive mechanism: the four lifting cylinders 12 drive the upper and lower lifting tray 7 to descend, precisely docking the new fixture with the machine tool 31. The diameter of the positioning pin of the conical guide structure 25 is smaller than the diameter of the positioning hole at the bottom of the fixture (the pin diameter is 2mm smaller than the opening on the fixture), providing a coarse guide adjustment margin for the fixture to fall. After it is in place, the automatic locking mechanism of the fixture in the machine tool 31 locks it. The electrical control box 30 controls the front and rear drive mechanism: the first-stage rod cylinder 10 and the second-stage rodless cylinder 11 drive the front and rear push-pull platform 6 and the upper and lower lifting tray 7 to return to the outside of the machine tool 31. Once the process is complete, machine tool 31 can begin the first piece trial cut verification.

Claims

1. A quick-change device for a CNC machining center fixture, characterized in that, The machine tool includes an external pre-adjustment platform, guide rails, front and rear push-pull platforms, upper and lower lifting trays, front and rear drive mechanisms, lifting drive mechanisms, anti-fall-off mechanisms, and an electrical control box. The external pre-adjustment platform is equipped with a positioning mechanism for docking with a CNC machining center. The guide rails include an external guide rail and an internal guide rail. The external guide rail is installed on the external pre-adjustment platform, and the internal guide rail is installed inside the machine tool, located at a corresponding extension position of the external guide rail. The front and rear push-pull platforms are slidably mounted on the guide rails. The upper and lower lifting trays are mounted on the front and rear push-pull platforms. The pallet is used to support the clamp. The front and rear drive mechanisms are mounted on the external pre-adjustment platform. The output end of the front and rear drive mechanisms is connected to the front and rear push-pull platforms. The front and rear drive mechanisms are used to drive the front and rear push-pull platforms to slide along the guide rail. The lifting drive mechanism is mounted on the front and rear push-pull platforms. The output end of the lifting drive mechanism is connected to the upper and lower lifting pallets. The anti-drop mechanism is mounted on the front and rear push-pull platforms. The anti-drop mechanism is used to lock the upper and lower lifting pallets when they are in the raised position. The electrical control box is used to control the actions of the front and rear drive mechanisms, the lifting drive mechanism, and the anti-drop mechanism.

2. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The external guide rails include an external left guide rail and an external right guide rail, and the internal guide rails include an internal left guide rail and an internal right guide rail. The external left guide rail corresponds to the internal left guide rail, and the external right guide rail corresponds to the internal right guide rail. External limit blocks are provided on the external left guide rail and the external right guide rail, and internal limit blocks are provided on the internal left guide rail and the internal right guide rail.

3. The quick-change device for CNC machining center fixtures according to claim 2, characterized in that, The guide rail is provided with a number of precision cam bearings, which are respectively installed in the horizontal and vertical positions of the outer left guide rail and the outer right guide rail.

4. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The front and rear drive mechanism includes a primary rod cylinder and a secondary rodless cylinder. The primary rod cylinder and the secondary rodless cylinder are connected by a hinge structure, and the output end of the secondary rodless cylinder is connected to the front and rear push-pull platform.

5. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The lifting drive mechanism includes four lifting cylinders, which are respectively installed at the four corners of the front and rear push-pull platforms. The piston rod of each lifting cylinder is connected to the upper and lower lifting trays. Guide rods are provided at the four corners of the front and rear push-pull platforms, and guide sleeves are correspondingly provided on the upper and lower lifting trays. The guide rods and guide sleeves are slidably engaged.

6. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The anti-detachment mechanism includes a left pin, a right pin, and a left cylinder and a right cylinder that drive the left pin and the right pin respectively. The left pin and the right pin are installed on the front and rear push-pull platform. When the upper and lower lifting trays are raised to the highest position, the left pin and the right pin extend and are located below the upper and lower lifting trays.

7. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The positioning mechanism is located at the bottom of the external pre-adjustment platform. The positioning mechanism includes a liftable roller, a coarse positioning guide mechanism, a connecting bracket, a positioning bracket, and a locking bracket. The coarse positioning guide mechanism is used to cooperate with the coarse positioning guide rod on the machine tool. The connecting bracket and the positioning bracket are used to contact the limiting surface of the machine tool to achieve positioning. The locking bracket is used to lock the external pre-adjustment platform to the machine tool.

8. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, It also includes a detection system, which comprises a rear limit switch, a front limit switch, a lower limit switch, an upper limit switch, a proximity switch, and a clamp positioning limit switch. The rear limit switch is used to detect the return positioning signal of the front and rear push-pull platforms, the front limit switch is used to detect the advance positioning signal of the front and rear push-pull platforms, the lower limit switch is used to detect the positioning signal of the upper and lower lifting trays descending to the lowest position, the upper limit switch is used to detect the positioning signal of the upper and lower lifting trays rising to the highest position, the proximity switch is used to detect the extension and retraction states of the anti-drop mechanism, and the clamp positioning limit switch is used to detect whether the clamp is in position.

9. The quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The upper and lower lifting pallets are provided with a conical guide structure, and the diameter of the positioning pin of the conical guide structure is smaller than the diameter of the positioning hole at the bottom of the fixture; the front and rear push-pull platforms are provided with a coarse guide device, which is used for the initial guidance of the fixture when it is placed on the upper and lower lifting pallets.

10. A quick-change device for CNC machining center fixtures according to claim 1, characterized in that, The electrical control box communicates with the electrical cabinet of the CNC machining center via quick-connect connectors for point-to-point I / O communication.

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