A sequential tightening mechanism based on coordinate control

Abstract

The utility model discloses a kind of sequential tightening mechanism based on coordinate control, belong to mechanical assembly technical field.The mechanism includes frame and the guide rail assembly of three directions of X, Y, Z set on it, X direction displacement sensor, Y direction displacement sensor and Z direction displacement sensor are respectively equipped on the guide rail assembly.Z direction guide rail seat is equipped with electric torque gun by Z direction telescopic sleeve, and gravity balance is carried out by spring balancer.The core of the utility model is, three displacement sensors real-time feedback the space coordinates of tightening gun, and carry out linkage control with the preset sequential coordinate program in tightening controller, only when operator moves to the correct coordinate point of current only unlocking and completes qualified tightening, system only then unlocks next coordinate point.So fundamentally, it eliminates the repeated tightening and missing problem in multi-thread connection assembly, simple structure, low cost, and mistake-proofing reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of mechanical assembly technology, specifically to a tightening mechanism for assembling multiple threaded connection points, and in particular to a sequential tightening mechanism that can prevent repeated tightening and omissions. Background Technology

[0002] In the assembly and production of products such as automotive seats, there are often situations where multiple threaded connections need to be tightened sequentially. Existing technology typically employs a tightening system consisting of a tightening controller, an electric torque gun, a Manufacturing Execution System (MES), and a production line PLC interlock. Its error-proofing logic relies on the MES's barcode scanning selection program and line interlocking to ensure that the torque and quantity are within acceptable limits before release.

[0003] However, the above solution has a significant drawback: the system cannot effectively identify whether the operator has tightened the same threaded hole repeatedly. When two tightening points are close together, the operator may, due to negligence, tighten the first point to a passing condition and then tighten it a second time at the same point. The system will then record these as two passing tightening points, leading to a serious omission incident—that is, one threaded connection point is completely not tightened, which seriously affects product quality and safety. Utility Model Content

[0004] 1. Technical problem to be solved: The purpose of this invention is to overcome the shortcomings of the prior art and provide a sequential tightening mechanism based on coordinate control. By introducing a combination of mechanical coordinate positioning and electrical interlock control, it fundamentally eliminates the possibility of repeated tightening and missing parts.

[0005] 2. Technical Solution: To solve the above problems, the present invention adopts the following technical solution.

[0006] A coordinate-controlled sequential tightening mechanism includes a frame, on the top of which two parallel and symmetrically arranged X-axis guide rods are fixedly installed, and an X-axis displacement sensor for detecting the X-axis position is provided on the frame. A Y-guide rail seat is slidably connected to two X-guide rail rods via a linear sliding pair; two parallel and symmetrically arranged Y-guide rail rods are fixedly installed on the Y-guide rail seat; and a Y-direction displacement sensor for detecting the Y-direction position is provided on the Y-guide rail seat. A Z-guide rail seat is slidably connected to two Y-guide rail rods via a linear sliding pair; A Z-axis telescopic sleeve is fixedly installed in the middle of the Z-axis guide rail seat. The telescopic rod of the Z-axis telescopic sleeve extends vertically downward, and a connecting column is fixedly connected to the end of the telescopic rod. A mounting bracket is fixedly connected to the bottom of the connecting column, and an electric torque gun is rotatably mounted on the mounting bracket via a rolling bearing. A pair of lifting lugs are symmetrically fixed to the side wall of the connecting column; Both sides of the top of the Z-axis telescopic sleeve are equipped with spring balancers, and the ends of the cables of the spring balancers are provided with hooks, which are connected to the lifting lugs. The Z-axis telescopic sleeve is equipped with a Z-axis displacement sensor for detecting the Z-axis position.

[0007] Preferably, the X-axis displacement sensor, Y-axis displacement sensor and Z-axis displacement sensor are connected to a tightening controller, which is electrically connected to the electric torque gun.

[0008] Preferably, the rated balancing force of the spring balancer is 25N to 50N.

[0009] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this utility model has the following advantages: (1) A spatial coordinate error prevention system was established: Through displacement sensors in the X, Y, and Z directions, the system can obtain the precise coordinates of the electric torque gun in space in real time. The MES system can pre-program the coordinates of multiple tightening points for each product. The operator must move the torque gun to the first coordinate point specified by the system, and the system will only unlock the next coordinate point after the torque at that point is qualified. This process forces the operator to operate in the preset order and position, which logically and physically avoids the possibility of repeating work at the same coordinate point.

[0010] (2) Simple and reliable structure, low cost: The core motion mechanism (X, Y, Z axes) of this utility model adopts a manual sliding method without power drive, and only uses sensors for position feedback. Compared with the fully automatic robot tightening system, it greatly reduces manufacturing costs and maintenance complexity, while achieving similar error prevention functions, making it very suitable for modification and upgrading on existing production lines.

[0011] (3) Effortless and flexible operation: The spring balancer effectively offsets most of the weight of the electric torque gun, making it very easy and effortless for the operator to move up and down (Z-axis) and to position precisely. At the same time, the electric torque gun is mounted on the mounting bracket through rolling bearings and can rotate 180 degrees in the horizontal plane, which is convenient to meet the tightening requirements of different angles, improving the flexibility of operation and ergonomics.

[0012] (4) Forming a closed-loop control: The system will only record the completion of the step and proceed to the next step when both conditions of "correct spatial coordinates" and "qualified tightening torque" are met at the same time, thus forming a complete quality closed-loop control and ensuring that the assembly process is foolproof.

[0013] It should be noted that structures not described in this utility model, such as specific models of guide rail components, can be implemented using existing technologies and will not be elaborated further. Attached Figure Description

[0014] Figure 1 This is a front view of the overall structure of this utility model; Figure 2 This is a partially enlarged structural diagram of the electric torque gun, connecting column, and mounting part in this utility model; Figure 3 This is a front view of the overall structure of this utility model; Figure 4 This is a side view of the overall structure of this utility model.

[0015] Explanation of the labels in the diagram: 1. Frame; 2. X-axis guide rail rod; 21. X-axis displacement sensor; 3. Y-axis guide rail seat; 31. Y-axis displacement sensor; 4. Y-axis guide rail rod; 5. Z-axis guide rail seat; 6. Z-axis telescopic sleeve; 61. Z-axis displacement sensor; 62. Connecting column; 63. Lifting lug; 64. Mounting bracket; 7. Electric torque gun; 8. Spring balancer. Detailed Implementation

[0016] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the utility model will be more thorough and complete.

[0017] like Figures 1 to 4 As shown, the mechanical body of the sequential tightening mechanism based on coordinate control described in this utility model is connected and fixed above the automotive seat assembly line by a sturdy frame 1.

[0018] X-axis movement system: Two parallel X-axis guide rods 2 are fixed to the top of the frame 1 by bolts or welding. A Y-axis guide seat 3 is mounted on the X-axis guide rods 2 via a linear sliding pair (e.g., a linear bearing or slider) integrated at its bottom, allowing the entire Y-axis guide seat 3 to move smoothly and without power in the X-axis direction by manual operation. The X-axis displacement sensor 21 is preferably a linear potentiometer or magnetic scale, its body fixed to the frame 1, and its sensing end connected to the Y-axis guide seat 3 for real-time measurement of the absolute position of the Y-axis guide seat 3 in the X-axis direction.

[0019] Y-axis movement system: Two parallel Y-axis guide rods 4 are fixedly mounted on the Y-axis guide rail seat 3. The Z-axis guide rail seat 5 is also slidably connected to the Y-axis guide rods 4 via a linear sliding pair (e.g., a linear bearing or slider), allowing the operator to manually push it to move in the Y-axis direction. A Y-axis displacement sensor 31 is mounted on the Y-axis guide rail seat 3 in a similar manner to accurately detect the Y-axis position of the Z-axis guide rail seat 5.

[0020] Z-axis and actuator system: A Z-axis telescopic sleeve 6 is fixedly installed in the middle of the Z-axis guide rail seat 5. The sleeve has a linear bearing inside, forming a linear sliding pair in the Z-direction, which can be manually extended and retracted. The Z-axis displacement sensor 61 detects the extension length of the telescopic rod (i.e., the Z coordinate).

[0021] The end of the telescopic rod is fixed to the connecting column 62 by bolts. The bottom of the connecting column 62 is mounted with an electric torque gun 7 via a mounting bracket 64. Specifically, a rolling bearing is mounted on the mounting bracket 64, and the gun body of the electric torque gun 7 is fixed to the inner or outer ring of the rolling bearing. This allows the operator to easily rotate the electric torque gun 7 ±90° in the horizontal plane (a total range of 180°) to accommodate bolts at different angles.

[0022] To balance the weight of the electric torque gun 7 and its accessories, a spring balancer 8 is installed on each side of the top of the Z-axis telescopic sleeve 6. The hook at the end of the cable of the spring balancer 8 is directly hooked onto the lifting lugs 63 symmetrically arranged on both sides of the connecting column 62. Calculations show that the rated balancing force of the spring balancer 8 is preferably 30N (approximately corresponding to the weight of 3kg). This value falls within the range of 25N to 50N, effectively allowing the operator to experience a "weightless" operating feel, greatly reducing labor intensity. The tightening controller (not shown in the figure) is electrically connected to the displacement sensor and the electric torque gun, and is integrated into the MES system.

[0023] The core of the electrical control system is a tightening controller (not shown in the diagram, typically located in an electrical cabinet next to the production line). The X-axis displacement sensor 21, Y-axis displacement sensor 31, and Z-axis displacement sensor 61 are all connected to this tightening controller via signal lines. Simultaneously, the tightening controller and the electric torque gun 7 are powered, controlled, and communicate with each other via a dedicated cable. The tightening controller itself is connected to the factory network and can interact with the MES (Manufacturing Execution System).

[0024] In actual tightening operations, the vibration generated by the electric torque gun 7 is transmitted to the entire mechanism through the mounting bracket 64. Thanks to the rigid structure formed between the frame 1 and each guide rail seat and guide rail rod, this vibration is effectively suppressed. Testing showed that the maximum spatial deviation (i.e., amplitude) of the electric torque gun 7 caused by this vibration was controlled within ±15mm. This value is within the coordinate tolerance design considerations of the control system, therefore it will not trigger false alarms, nor will it affect the error-proofing logic of sequential tightening. This characteristic ensures the reliability of the mechanism under continuous vibration conditions, and eliminates the need for complex vibration damping devices, reducing costs and maintenance complexity.

[0025] Its detailed workflow is as follows: Step 1: Program Invocation and Initialization. When the tray with the seat frame is transferred to the workstation, the operator scans the barcode on the tray using the MES barcode scanner. Based on the barcode information, the MES system sends the corresponding "tightening program" to the tightening controller. This program includes the number of bolts to be tightened (e.g., 4), as well as the three-dimensional coordinates (X, Y, Z) and target torque value of each bolt. At this time, the tightening controller only unlocks the first coordinate point in the program (e.g., P1) and waits for a signal.

[0026] Step Two: Spatial Positioning and Coordinate Verification. The operator manually holds the electric torque gun 7 and aligns the sleeve of the gun head with the first bolt by freely moving the X, Y, and Z axes. During this process, the three displacement sensors continuously feed coordinate data back to the tightening controller. The controller compares the real-time coordinates with the target coordinates P1. Only when the real-time coordinates enter a preset tolerance range (e.g., ±10mm) centered at point P1 is the system considered to have "successfully matched coordinates".

[0027] Step 3: Tightening Execution and Result Judgment. Once the "coordinate matching" condition is met, the tightening controller will issue a visual / audible prompt signal (such as a green light or a short beep), indicating that the electric torque gun 7 is enabled. At this point, the operator can press down on the electric torque gun 7 and activate the trigger to perform the tightening operation. The tightening controller monitors the torque value in real time and automatically stops once the preset target torque is reached.

[0028] Step Four: Sequential Unlocking and Logic Interlocking. After the first bolt is tightened to the correct tightness, the tightening controller will perform two key operations: Record successful: Marking coordinate point P1 in memory has been completed.

[0029] Sequential unlock: Immediately lock the startup permission of the current coordinate point P1, and at the same time unlock the startup permission of the next coordinate point P2.

[0030] This means that even if the operator moves the gun to point P1 again, they cannot activate the electric torque gun 7. They must move the gun to point P2, and only after the system re-identifies the coordinates and issues an enable signal can they perform a second tightening. This logical interlocking mechanism is the core of preventing repeated tightening.

[0031] Step 5: Cycle and Release. The operator repeats steps two through four until all bolts at all coordinate points within the program are tightened to the required tightness. Once the last bolt is tightened to the required tightness, the tightening controller sends a "Workstation Operation Complete" signal to the production line's PLC, allowing the production line to unlock and permit the workpiece to flow to the next station. If any tightening torque is incorrect, or if the operator attempts to start at the wrong coordinate point, the controller will immediately alarm (red light, continuous beep) and prevent the process from continuing, requiring personnel intervention and inspection.

[0032] This invention perfectly combines a simple mechanical structure with intelligent electronic control logic. Through coordinate uniqueness and sequential interlocking, it eliminates human errors such as repeated tightening and omissions at the source. Its manual sliding design, while ensuring accuracy and error prevention, offers significantly lower cost and maintenance compared to fully automated robots, making it ideal for large-scale deployment in low-to-medium speed production processes requiring high reliability and error prevention.

[0033] The above-described embodiments are merely illustrative of certain implementations of this utility model, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A sequential tightening mechanism based on coordinate control, comprising a frame (1), characterized in that: Two parallel and symmetrically arranged X-axis guide rods (2) are fixedly installed on the top of the frame (1), and an X-axis displacement sensor (21) for detecting the X-axis position is provided on the frame (1). A Y-guide rail seat (3) is slidably connected to two X-guide rail rods (2) through a linear sliding pair; two parallel and symmetrically arranged Y-guide rail rods (4) are fixedly installed on the Y-guide rail seat (3); a Y-direction displacement sensor (31) for detecting the Y-direction position is provided on the Y-guide rail seat (3). A Z-guide rail seat (5) is slidably connected to two Y-guide rail rods (4) via a linear sliding pair; A Z-direction telescopic sleeve (6) is fixedly installed in the middle of the Z-direction guide rail seat (5). The telescopic rod of the Z-direction telescopic sleeve (6) extends vertically downward, and a connecting column (62) is fixedly connected to the end of the telescopic rod. A mounting bracket (64) is fixedly connected to the bottom of the connecting column (62), and an electric torque gun (7) is rotatably mounted on the mounting bracket (64) via a rolling bearing. A pair of lugs (63) are symmetrically fixed to the side wall of the connecting column (62); Both sides of the top of the Z-direction telescopic sleeve (6) are equipped with spring balancers (8), and the ends of the cables of the spring balancers (8) are provided with hooks, which are connected to the lifting lugs (63). The Z-direction telescopic sleeve (6) is equipped with a Z-direction displacement sensor (61) for detecting the Z-direction position.

2. The sequential tightening mechanism based on coordinate control according to claim 1, characterized in that: The X-direction displacement sensor (21), Y-direction displacement sensor (31) and Z-direction displacement sensor (61) are all connected to a tightening controller, which is electrically connected to the electric torque gun (7).

3. The sequential tightening mechanism based on coordinate control according to claim 1, characterized in that: The rated balancing force of the spring balancer (8) is 25N to 50N.

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