A misoperation-proof limit switch with double-contact triggering
Patent Information
- Application Number
- CN202522559393.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-12-02
Smart Images
Figure CN224907804U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of limit switch technology, specifically a limit switch with dual-contact triggering to prevent accidental operation. Background Technology
[0002] Limit switches, as core components in industrial automation control systems, are widely used in many fields such as machinery manufacturing, automobile assembly, logistics transportation, elevator control, and new energy equipment. They achieve precise detection and control of the movement position of equipment through physical contact, which is directly related to the operating efficiency and safety level of the whole system. In high-precision scenarios such as new energy vehicle battery module assembly lines, CNC machine tools, and intelligent conveying, a single production line often needs to be equipped with hundreds of limit switches, and stringent requirements are placed on their anti-interference ability, triggering accuracy, and mechanical life. Currently, most mainstream contact-type limit switches on the market adopt a single-contact mechanical trigger structure. They directly contact the actuator through external moving parts to drive the internal contacts to open and close to output control signals. However, this type of structure has significant drawbacks in practical applications: First, the risk of false triggering is high. Mechanical vibration, equipment start-up and shutdown impacts, or dust accumulation in industrial sites can easily cause unexpected displacement of the actuator, leading to false contact of the contacts. This can result in abnormal equipment shutdown, positioning deviation, or even collision accidents. For example, in a PLC automatic door control system, false triggering caused by vibration interference may cause the door to start and stop suddenly, affecting both operational accuracy and safety hazards. In CNC machine tool hard limit protection, false triggering may also lead to processing interruption and workpiece scrapping. As the manufacturing industry transforms towards high-end and intelligent manufacturing, fields such as new energy and semiconductors are placing higher demands on the anti-maloperation performance of limit switches. The market urgently needs a limit switch that can achieve anti-maloperation and high reliability through multiple trigger verifications to address the technical pain points of traditional products in complex industrial environments and meet the safe operation requirements of high-precision control scenarios. Utility Model Content
[0003] The purpose of this invention is to provide a limit switch with dual-contact triggering to prevent accidental activation, thereby solving the problem of poor accidental activation prevention mentioned in the background art.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a limit switch with dual-contact triggering for preventing accidental operation, comprising a first contact mounted on one side surface of a switch housing, and a rotating contact frame mounted on the outer surface of the side of the switch housing on which the first contact is mounted, wherein a contact frame is fixedly connected to one end of the contact frame, and a rotating contact wheel is mounted on one end of the contact frame. A mounting plate is fixedly connected to the side surface of the switch box facing the contact wheel, and an electric motor is fixedly installed on the outer surface of the mounting plate. A turntable is fixedly connected to one end of the output shaft of the electric motor, and a rotating rod is fixedly connected to the outer surface of the turntable. A second contact point is installed inside the rotating rod, and a sliding contact rod is installed at one end of the rotating rod. A rotating contact wheel is installed at one end of the contact rod. A contact block is fixedly provided on the side surface of the contact frame facing the mounting plate. An adjusting rod is installed on the outer surface of the contact frame, and a sliding insertion rod is also installed on the outer surface of the contact frame.
[0005] Preferably, a spring is connected between the end of the contact frame that is connected to the switch box and the switch box, and the contact frame is positioned directly opposite the first contact point.
[0006] Using the above technical solution, the reset spring can release elastic potential energy to drive the contact frame to rotate in the opposite direction and reset after the external triggering force disappears, so that the contact frame is completely separated from the first contact and the switch is restored to its initial standby state. The direct alignment of the contact frame and the first contact ensures that when the contact frame is driven to rotate by the contact frame, it can accurately reach the first contact, avoiding the initial triggering failure caused by positional deviation, and laying a reliable preliminary testing foundation for subsequent dual-contact verification.
[0007] Preferably, the rotating rod is set at an equal angle on the outer surface of the turntable, and a spring connects the rotating rod and the contact rod.
[0008] With the above technical solution, the rotating rods are evenly distributed on the surface of the turntable, and can form a continuous and uniform circular motion trajectory with the rotation of the turntable. This ensures that when the contact block on the contact frame is in a stable trigger position, there is always a contact wheel that can contact the contact block in time, avoiding triggering delay or missed triggering caused by uneven distribution of the rotating rods. At the same time, the spring between the rotating rod and the contact rod can push the contact rod to slide and reset to the outside of the rotating rod after the contact wheel disengages from the contact block, so that the contact rod separates from the second contact point, preparing for the next contact verification and ensuring the cyclic reliability of the second contact point triggering.
[0009] Preferably, one end of the contact rod located inside the rotating rod is positioned directly opposite the second contact point, the contact wheel is positioned directly opposite the contact block, and both the upper and lower ends of the contact block are provided with arc-shaped chamfers.
[0010] By adopting the above technical solution, the direct alignment of the contact rod and the second contact point ensures that when the contact rod slides inward under the pressure transmitted by the contact wheel, the second contact point can be accurately triggered, ensuring the effective output of the verification signal. The direct alignment of the contact wheel and the contact block is the core prerequisite for their physical contact. The arc-shaped chamfer design at the upper and lower ends of the contact block can prevent mechanical jamming at the moment of contact between the contact wheel and the contact block, while reducing frictional loss during contact, extending the service life of the contact wheel and the contact block, and reducing the frequency of component maintenance.
[0011] Preferably, the adjusting rod and the contact frame are threaded together, and one end of the adjusting rod is positioned directly opposite the first contact point. A spring is connected between the plug rod and the contact frame. Holes are equidistantly opened on the surface of the adjusting rod, and one end of the plug rod is engaged with the adjusting rod through the holes on the surface of the adjusting rod.
[0012] Using the above technical solution, the threaded connection structure between the adjusting rod and the contact frame is adjustable. By rotating the adjusting rod in the forward or reverse direction, the operator can flexibly change the initial distance between the adjusting rod and the first contact point. The smaller the distance, the more the contact frame needs to rotate slightly to trigger the first contact point, resulting in higher sensitivity. The larger the distance, the greater the rotation angle required for triggering, resulting in lower sensitivity. This meets the differentiated requirements of different industrial equipment for limit trigger sensitivity. In addition, the spring between the plug rod and the contact frame provides a continuous engaging driving force for the plug rod. Combined with the equidistant holes on the surface of the adjusting rod, it can be firmly locked after the position of the adjusting rod is determined, effectively preventing the adjusting rod from rotating on its own due to industrial vibration and equipment start-up and shutdown impacts. This ensures long-term stability of sensitivity parameters and reduces the maintenance costs of subsequent re-inspection and adjustment.
[0013] Compared with the prior art, the beneficial effects of this utility model are: the anti-misoperation limit switch with dual-contact triggering is: 1. By driving the turntable to rotate via an electric motor, the rotating rod and its contact rod and contact wheel achieve continuous circular motion, thus constructing a dual triggering mechanism of "first contact trigger + second contact verification". Only when an external component contacts the contact wheel and continuously applies pressure to make the contact wheel drive the contact frame and contact frame to rotate synchronously, and the contact frame maintains a stable state after rotation, will the contact block make precise contact with the rotating contact wheel, pushing the contact rod to slide into the rotating rod and triggering the second contact. At this time, the electrical signal output by the second contact and the electrical signal of the first contact triggered by the rotation of the contact frame form a double contact signal superposition, which can finally output an effective control signal. This mechanism completely eliminates the single contact false triggering caused by unexpected factors such as industrial site vibration and equipment start-up and shutdown impact, avoiding abnormal equipment shutdown, positioning deviation or collision accidents. It is especially suitable for scenarios with extremely high triggering accuracy requirements, such as PLC automatic doors and CNC machine tools, and can reduce the risk of workpiece scrapping and processing interruption. 2. The threaded connection between the adjusting rod and the contact frame enables flexible adjustment of the first contact trigger sensitivity. Operators can rotate the adjusting rod to change the initial distance between the adjusting rod and the first contact, thereby adjusting the required rotation angle threshold of the contact frame. This meets the diverse needs of different industrial equipment for limit trigger accuracy. Simultaneously, the slidingly mounted plug-in rod on the contact frame can lock the adjusting rod firmly in its current position after adjustment by engaging with equidistant holes on the surface of the adjusting rod. This locking structure effectively prevents the adjusting rod from rotating on its own due to industrial vibrations, mechanical shocks, etc., ensuring long-term stability of the sensitivity parameters and eliminating the need for frequent re-inspection and adjustment, thus reducing equipment maintenance costs. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a three-dimensional structural diagram of the connection between the mounting plate and the electric motor of this utility model; Figure 3 This is a three-dimensional structural diagram of the connection between the contact frame and the contact block of this utility model; Figure 4 This is a three-dimensional structural diagram of the connection between the mounting plate, turntable, and rotating rod of this utility model; Figure 5 This is a three-dimensional structural diagram of the connection between the mounting plate, electric motor, and turntable of this utility model; Figure 6 This is a three-dimensional structural diagram of the connection between the contact frame, adjusting rod, and plug-in rod of this utility model.
[0015] In the diagram: 1. Switch box; 2. First contact; 3. Contact frame; 4. Abutment frame; 5. Abutment wheel; 6. Mounting plate; 7. Electric motor; 8. Turntable; 9. Rotating rod; 10. Second contact; 11. Contact rod; 12. Contact wheel; 13. Contact block; 14. Adjusting rod; 15. Plug-in rod. Detailed Implementation
[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0017] Please see Figures 1-6 This utility model provides a technical solution: a limit switch with dual-contact triggering to prevent accidental operation.
[0018] Example 1: In this example, a first contact 2 is installed on one side surface of the switch box 1, and a rotating contact frame 3 is installed on the outer surface of the side of the switch box 1 where the first contact 2 is installed. A contact frame 4 is fixedly connected to one end of the contact frame 3, and a rotating contact wheel 5 is installed on one end of the contact frame 4. A spring is connected between the end of the contact frame 3 and the switch box 1, and the contact frame 3 is positioned directly opposite the first contact 2. The switch box 1 serves as the supporting base of the overall structure, providing a stable mounting reference for the first contact 2 and the contact frame 3. The first contact 2 is fixed to one side surface of the switch box 1 and is directly opposite the contact frame 3. This direct alignment ensures that the contact frame 3 can accurately reach the first contact 2 when it rotates. The contact frame 3 is mounted on the outer surface of the switch box 1 through a rotating structure. A return spring is connected between one end of the contact frame 4 and the switch box 1. A freely rotating contact wheel 5 is installed at the end of the contact frame 4. The contact wheel 5 reduces frictional wear with external moving parts through its rotational characteristics, thus extending the mechanical life. When the moving parts of the external device reach the limit position, they will first make physical contact with the abutment wheel 5 and apply continuous pressure. After being pressed, the abutment wheel 5 rotates around its own axis, which in turn drives the abutment frame 4 fixed to it to rotate synchronously. The abutment frame 4 further transmits power to the contact frame 3, causing the contact frame 3 to rotate around its connection point with the switch box 1 and compress the return spring. As the contact frame 3 rotates, it gradually moves closer to the side of the first contact 2 until it triggers the first contact 2 to output an initial signal, completing the preliminary detection of the device "reaching the limit". When the external moving part leaves the limit position and stops applying pressure to the abutment wheel 5, the reset spring between the contact frame 3 and the switch box 1 releases its elastic potential energy, pulling the contact frame 3 to rotate in the opposite direction and return to the center. The contact frame 3 drives the abutment frame 4 and the abutment wheel 5 to reset synchronously. The contact frame 3 is completely separated from the first contact 2, the first contact 2 stops outputting signals, and the entire structure returns to its initial state, waiting for the next trigger.
[0019] Example 2: This example discloses the following based on Example 1: A mounting plate 6 is fixedly connected to the side surface of the switch box 1 facing the contact wheel 5, and an electric motor 7 is fixedly installed on the outer surface of the mounting plate 6. A turntable 8 is fixedly connected to one end of the output shaft of the electric motor 7, and a rotating rod 9 is fixedly connected to the outer surface of the turntable 8. A second contact point 10 is installed inside the rotating rod 9, and a sliding contact rod 11 is installed at one end of the rotating rod 9. A rotating contact wheel 12 is installed at one end of the contact rod 11. A contact block 13 is fixedly provided on the side surface of the contact frame 4 facing the mounting plate 6. The rotating rod 9 is set at equal angles on the outer surface of the turntable 8, and a spring connects the rotating rod 9 and the contact rod 11; The contact rod 11 is located inside the rotating rod 9 with one end facing the second contact point 10, the contact wheel 12 is facing the contact block 13, and both the upper and lower ends of the contact block 13 are rounded and chamfered. A mounting plate 6 is fixedly connected to the side surface of the switch box 1 facing the contact wheel 5. The mounting plate 6 provides rigid support for the electric motor 7. The electric motor 7 is fixed to the outer surface of the mounting plate 6, and its output shaft is fixedly connected to the turntable 8. After being powered on, it can drive the turntable 8 to rotate continuously at a constant speed. Multiple rotating rods 9 are fixed at equal angles on the outer surface of the turntable 8. When the turntable 8 rotates, it drives all the rotating rods 9 to perform synchronous circular motion. A second contact 10 is installed inside each rotating rod 9, and a contact rod 11 is slidably installed at the end of the rotating rod 9. The contact rod 11 is connected to the contact point 10. A return spring is connected between the rotating rods 9. One end of the contact rod 11 located inside the rotating rod 9 is directly opposite the second contact point 10 to ensure accurate triggering during sliding. A rotatable contact wheel 12 is installed on the outer end of the contact rod 11 to reduce friction with other components. At the same time, a contact block 13 is fixedly installed on the side of the contact frame 4 facing the mounting plate 6. The upper and lower ends of the contact block 13 are rounded and chamfered to avoid jamming with the contact wheel 12. Its position is directly opposite to the circumferential motion trajectory of the contact wheel 12 to ensure accurate contact when the rotating rod 9 drives the contact wheel 12 to rotate. When an external component contacts the contact wheel 5, the contact frame 3 is rotated via the contact frame 4, triggering the first contact 2 to output an initial signal. If the trigger is due to unexpected factors such as vibration or impact, the contact frame 3 will quickly return to its original position due to spring reset and will not be able to maintain a stable state, thus interrupting subsequent verification and preventing false triggering. If external components continue to apply pressure, the contact frame 3 will maintain stable rotation, causing the contact block 13 on the contact frame 4 to be in a fixed position. At this time, the electric motor 7 drives the turntable 8 to rotate, and the turntable 8 drives the rotating rod 9, contact rod 11, and contact wheel 12 to make circular motion. When the contact wheel 12 rotates to the position of the contact block 13, the contact block 13 applies radial pressure to the contact wheel 12, pushing the contact rod 11 to slide into the rotating rod 9, compressing the reset spring. The contact rod 11 slides to contact the second contact 10, triggering the second contact 10 to output a verification signal.
[0020] The limit switch outputs a "valid limit signal" to the equipment control system only when the initial signal of the first contact 2 and the verification signal of the second contact 10 are present and superimposed. This controls the equipment to stop, change direction, and perform other actions. If either contact is not triggered, no valid signal is output, thus completely eliminating the risk of malfunction. After the external components leave, the contact frame 3 resets under the action of the spring, the contact block 13 moves away from the movement trajectory of the contact wheel 12 along with the contact frame 4, the contact rod 11 resets under the action of its own spring and separates from the second contact point 10, and the electric motor 7 continues to drive the turntable 8 to rotate, waiting for the next triggering of the contact block 13.
[0021] Example 3: This example discloses, based on Example 1 and Example 2, that an adjusting rod 14 is installed on the outer surface of the contact frame 3, and a sliding plug rod 15 is installed on the outer surface of the contact frame 3. The adjusting rod 14 is threadedly connected to the contact frame 3, and one end of the adjusting rod 14 is positioned directly opposite the first contact point 2. A spring is connected between the plug rod 15 and the contact frame 3. Holes are equidistantly opened on the surface of the adjusting rod 14, and one end of the plug rod 15 is engaged with the adjusting rod 14 through the holes on the surface of the adjusting rod 14. An adjusting rod 14 and a plug-in rod 15 are installed on the outer surface of the contact frame 3. The adjusting rod 14 is threadedly connected to the contact frame 3. One end of the adjusting rod 14 is directly opposite the first contact point 2, and the other end extends to the outside of the contact frame 3, which is convenient for the operator to rotate and adjust. The plug-in rod 15 is installed on the contact frame 3 through a sliding structure and is connected to the contact frame 3 by a return spring. It can slide along the radial direction of the contact frame 3. Holes are equally spaced on the surface of the adjusting rod 14. One end of the plug-in rod 15 can be engaged with the adjusting rod 14 through the holes to lock the position of the adjusting rod 14. The operator pulls the plug rod 15 away from the adjusting rod 14. The plug rod 15 stretches the return spring, and its locking end disengages from the hole of the adjusting rod 14, releasing the lock on the adjusting rod 14. If it is necessary to increase the sensitivity, rotate the adjusting rod 14 to move it closer to the first contact point 2, reducing the angle threshold that the contact frame 3 needs to rotate—the contact frame 3 only needs to rotate slightly for the adjusting rod 14 to reach the first contact point 2. If it is necessary to decrease the sensitivity, rotate the adjusting rod 14 in the opposite direction to move it away from the first contact point 2, increasing the rotation angle threshold of the contact frame 3—the contact frame 3 needs to rotate significantly for the adjusting rod 14 to reach the first contact point 2. After adjustment, release the plug rod 15. The plug rod 15 slides in the opposite direction under the action of its own spring, and its locking end is re-inserted into the hole at the corresponding position of the adjusting rod 14, which firmly locks the adjusting rod 14 in the current position, preventing the adjusting rod 14 from rotating on its own due to industrial vibration and mechanical impact, ensuring that the sensitivity parameters are stable for a long time and that frequent re-inspection is not required.
[0022] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A limit switch with dual-contact triggering for preventing accidental operation, comprising a first contact (2) mounted on one side surface of a switch housing (1), and a rotating contact frame (3) mounted on the outer surface of the side of the switch housing (1) where the first contact (2) is mounted, characterized in that: One end of the contact frame (3) is fixedly connected to the abutment frame (4), and one end of the abutment frame (4) is equipped with a rotating abutment wheel (5).
2. The anti-misoperation limit switch with dual-contact triggering according to claim 1, characterized in that: The switch box (1) is fixedly connected to a mounting plate (6) on one side surface facing the abutment wheel (5), and an electric motor (7) is fixedly installed on the outer side surface of the mounting plate (6). One end of the output shaft of the electric motor (7) is fixedly connected to a turntable (8), and a rotating rod (9) is fixedly connected to the outer side surface of the turntable (8). A second contact point (10) is installed inside the rotating rod (9), and a sliding contact rod (11) is installed at one end of the rotating rod (9), and a rotating contact wheel (12) is installed at one end of the contact rod (11). A contact block (13) is fixedly provided on one side surface facing the mounting plate (6) of the abutment frame (4).
3. A limit switch with dual-contact triggering for preventing accidental operation as described in claim 1, characterized in that: An adjusting rod (14) is installed on the outer surface of the contact frame (3), and a sliding plug rod (15) is installed on the outer surface of the contact frame (3).
4. A limit switch with dual-contact triggering for preventing accidental operation as described in claim 1, characterized in that: One end of the contact frame (3) connected to the switch box (1) is connected to the switch box (1) by a spring, and the contact frame (3) is positioned directly opposite the first contact point (2).
5. A limit switch with dual-contact triggering for preventing accidental operation according to claim 2, characterized in that: The rotating rod (9) is set at equal angles on the outer surface of the turntable (8), and a spring is connected between the rotating rod (9) and the contact rod (11).
6. A limit switch with dual-contact triggering for preventing accidental operation according to claim 2, characterized in that: The contact rod (11) is located inside the rotating rod (9) with one end facing the second contact point (10), and the contact wheel (12) is located facing the contact block (13), with both the upper and lower ends of the contact block (13) having arc-shaped chamfers.
7. A limit switch with dual-contact triggering for preventing accidental operation according to claim 3, characterized in that: The adjusting rod (14) is threadedly connected to the contact frame (3), and one end of the adjusting rod (14) is positioned directly opposite the first contact point (2). A spring is connected between the plug rod (15) and the contact frame (3). Holes are equidistantly opened on the surface of the adjusting rod (14), and one end of the plug rod (15) is engaged with the adjusting rod (14) through the holes on the surface of the adjusting rod (14).