Automotive glass lifter wire winding apparatus
By integrating automated equipment for oiling, wire winding, and screw installation, the problems of incomplete assembly and low efficiency in the wire winding operation during the production of automotive window regulators have been solved, achieving efficient automated production and ensuring product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHU MOTIONTEC AUTOMOTIVE
- Filing Date
- 2023-08-29
- Publication Date
- 2026-05-26
AI Technical Summary
The existing wire winding operation in the production of automotive window regulators suffers from problems such as improper assembly, low production efficiency, high labor intensity, and the inability to monitor the screw installation torque and quantity, which affects product quality.
An automated device integrating oiling, wire winding, and screw installation was designed, including an oiling device, a wire winding fixture, and a screw installation device. Automated production is achieved through pneumatic actuators and a synchronous belt conveyor mechanism, and the assembly status of the steel wire is detected by a power on/off mechanism to ensure quality.
It improved production efficiency, reduced labor intensity, ensured product quality, and achieved automated monitoring of screw installation and accuracy of wire assembly.
Smart Images

Figure CN117142246B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of glass regulator production equipment. Specifically, this invention relates to a wire winding device for automotive glass regulators. Background Technology
[0002] A window regulator is a device for raising and lowering car door windows. The window regulator has a screw wheel cover and a screw wheel needs to be installed. The screw wheel is driven to rotate by a motor and has steel wire wound on it.
[0003] During the production of automotive window regulators, steel wire needs to be wound onto the lead wheel on the regulator motor. Before winding, the lead wheel on the regulator motor needs to be oiled, and after oiling, the lead wheel cover is placed on top. In the current production process, the winding is done manually by operators. Manual winding can lead to problems such as improper assembly, resulting in wire twisting. Moreover, it has low production efficiency and high labor intensity.
[0004] After the wire winding is completed, screws need to be installed to fix the wire wheel cover to the lifting motor. However, the screw installation torque, the number of screws, and the bolt installation depth cannot be monitored in real time, which affects product quality. Summary of the Invention
[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a wire winding device for automotive window regulators, with the purpose of improving production efficiency.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a wire winding device for automotive window regulators, comprising a frame, an oiling device disposed on the frame for oiling the tooth surface of the regulator motor and the wire wheel at an oiling station, a wire winding fixture for placing the regulator motor, and a screw mounting device disposed on the frame for screw mounting at a screw assembly station. The wire winding fixture is configured to move between the oiling station and the screw assembly station. After oiling the tooth surface of the regulator motor and the wire wheel is completed, the wire winding fixture drives the regulator motor and the wire wheel and wire wheel cover mounted on the regulator motor to move to the screw assembly station.
[0007] The oiling device includes an oiling bracket mounted on the frame, a first telescopic component mounted on the oiling bracket, a second telescopic component vertically mounted on the first telescopic component, a first oiling actuator, and a second oiling actuator mounted on the second telescopic component.
[0008] The first telescopic assembly includes a first telescopic actuator and a first telescopic arm body disposed on the first telescopic actuator. The second telescopic assembly includes a second telescopic actuator and a second telescopic arm body disposed on the second telescopic actuator. The second telescopic actuator and the first oiling actuator are disposed on the first telescopic arm body, and the second oiling actuator is disposed on the second telescopic arm body.
[0009] The first oiling actuator includes a first oiling actuator that is retractable in the vertical direction, a first oiling arm disposed on the first oiling actuator, and a first oiling head disposed on the first oiling arm for oiling the tooth surface of the lifting motor.
[0010] The second oiling actuator includes a second oiling actuator, a second oiling arm disposed on the second oiling actuator, and a second oiling head disposed on the second oiling arm for oiling the lead wheel mounted on the lifting motor. The second oiling actuator is used to control the rotation of the second oiling arm.
[0011] The frame is equipped with a first conveying device and a second conveying device. Two wire winding fixtures are provided. The second conveying device is equipped with a lifting device for controlling the lifting and lowering of one of the wire winding fixtures. The first and second conveying devices extend from the oiling station to the screw assembly station. The first conveying device is located above the second conveying device. The first conveying device is used to control the other wire winding fixture to move between the oiling station and the screw assembly station.
[0012] The first conveying device and the second conveying device are synchronous belt conveying mechanisms.
[0013] The screw mounting device includes a fixed frame mounted on the frame, an electric screwdriver, a lifting mechanism connected to the electric screwdriver and used to control the electric screwdriver to move vertically, a first position control mechanism connected to the lifting mechanism and used to control the lifting mechanism to move linearly horizontally, and a second position control mechanism connected to the first position control mechanism and used to control the first position control mechanism to move linearly horizontally.
[0014] The frame is equipped with a power-on / off mechanism, which detects the winding status and whether the first and second steel wires on the wire wheel are properly assembled.
[0015] The power-on / off mechanism includes a first conductive plate, a second conductive plate, an alarm, and a power supply. The first and second conductive plates are respectively connected to the positive and negative terminals of the power supply. The first conductive plate is used to contact the first steel wire, and the second conductive plate is used to contact the second steel wire. The alarm is set in the circuit between the first conductive plate and the positive terminal of the power supply or between the second conductive plate and the negative terminal of the power supply.
[0016] The automotive window regulator winding device of the present invention integrates an oiling device, a winding fixture, and a screw installation device into one unit, realizing the effective connection and coordination of motor winding and screw installation work, improving production efficiency and product quality, and reducing labor intensity. Attached Figure Description
[0017] This manual includes the following figures, which illustrate the following:
[0018] Figure 1 This is a schematic diagram of the structure of the automotive window regulator winding device of the present invention;
[0019] Figure 2 This is a schematic diagram of the oiling device;
[0020] Figure 3 This is the front view of the oiling device;
[0021] Figure 4 This is a schematic diagram of the screw mounting device;
[0022] The components in the diagram are labeled as follows: 1. Frame; 2. Lifting device; 3. Wire winding fixture; 4. First telescopic actuator; 5. First telescopic arm body; 6. Second telescopic actuator; 7. Second telescopic arm body; 8. First oiling actuator; 9. First oiling arm; 10. First oiling head; 11. Second oiling actuator; 12. Second oiling arm; 13. Second oiling head; 14. Fixing frame; 15. Electric screwdriver; 16. Lifting mechanism; 17. First position control mechanism; 18. Second position control mechanism; 19. Oiling bracket; 20. Clamping block. Detailed Implementation
[0023] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.
[0024] It should be noted that in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution; they are merely for the convenience of description.
[0025] like Figures 1 to 4As shown, the present invention provides a wire winding device for an automotive window regulator, including a frame 1, an oiling device mounted on the frame 1 for oiling the tooth surface of the regulator motor and the wire wheel at an oiling station, a wire winding fixture 3 for placing the regulator motor, and a screw mounting device mounted on the frame 1 for installing screws at a screw assembly station. The wire winding fixture 3 is configured to move between the oiling station and the screw assembly station. After oiling the tooth surface of the regulator motor and the wire wheel, the wire winding fixture 3 drives the regulator motor and the wire wheel and wire wheel cover mounted on the regulator motor to move to the screw assembly station.
[0026] Specifically, such as Figures 1 to 3 As shown, the oiling device includes an oiling bracket 19 mounted on a frame 1, a first telescopic component mounted on the oiling bracket 19, a second telescopic component vertically mounted on the first telescopic component, a first oiling actuator, and a second oiling actuator mounted on the second telescopic component. The first oiling actuator is used to apply oil to the tooth surface of the drive gear of the lifting motor, which is mounted on the motor shaft of the lifting motor. The second oiling actuator is used to apply oil to the threaded wheel mounted on the drive gear of the lifting motor. After the threaded wheel is mounted on the drive gear, when the lifting motor is running, the drive gear drives the threaded wheel to rotate, performing oiling while winding the thread.
[0027] like Figure 2 and Figure 3 As shown, the first telescopic assembly includes a first telescopic actuator 4 and a first telescopic arm body 5 disposed on the first telescopic actuator 4. The second telescopic assembly includes a second telescopic actuator 6 and a second telescopic arm body 7 disposed on the second telescopic actuator 6. The second telescopic actuator 6 and the first oiling actuator are disposed on the first telescopic arm body 5, and the second oiling actuator is disposed on the second telescopic arm body 7. The first telescopic actuator 4 is a horizontally telescopic component. The first telescopic actuator 4 is fixedly disposed on the upper end of the oiling bracket 19, and the lower end of the oiling bracket 19 is fixedly connected to the frame 1. The first telescopic actuator 4 is used to control the first telescopic arm body 5 and the second telescopic actuator 6 and the first oiling actuator on it to move linearly in a first direction, so that the first oiling actuator can move above the lifting motor and move away from above the lifting motor. The first direction is the horizontal direction. The second telescopic actuator 6 is a vertically telescopic component. The upper end of the second telescopic actuator 6 is fixedly connected to the end of the first telescopic arm body 5, and the lower end of the second telescopic arm body 7 is fixedly connected to the second telescopic actuator 6. The second telescopic actuator 6 is used to control the second telescopic arm body 7 and the second oiling actuator on it to move linearly in the vertical direction, so that the second oiling actuator can approach the lower thread wheel and move away from the thread wheel.
[0028] In this embodiment, both the first telescopic actuator 4 and the second telescopic actuator 6 are cylinders. After the first telescopic actuator 4 extends, it can move the first oiling actuator above the lifting motor. After the second telescopic actuator 6 extends, it can move the second oiling actuator downward, approaching the lower lead wheel. The pneumatic drive and control method can avoid grease fires caused by electronic control, thus ensuring higher safety.
[0029] like Figure 2 and Figure 3 As shown, the first oiling actuator includes a vertically extendable first oiling actuator 8, a first oiling arm 9 mounted on the first oiling actuator 8, and a first oiling head 10 mounted on the first oiling arm 9 for oiling the tooth surface of the lifting motor. The first oiling actuator 8 is a vertically extendable component. The upper end of the first oiling actuator 8 is fixedly connected to the end of the first telescopic arm body 5, and the first oiling arm 9 is fixedly connected to the lower end of the first oiling actuator 8. The first oiling actuator 8 is used to control the first oiling arm 9 and the first oiling head 10 on it to move linearly in the vertical direction, so that the first oiling head 10 can approach the lifting motor below and move away from the lifting motor. After the lifting motor is fixed on the wire winding fixture 3 located at the oiling station, the oiling device automatically starts to work. The first telescopic actuator 4 and the first oiling actuator 8 extend, and the first oiling head 10 approaches the drive gear of the lifting motor. The lifting motor is powered on and the drive gear rotates. Then the first oiling head 10 can apply grease to the surface of the drive gear, so that the entire circumference of the drive gear is coated with grease.
[0030] like Figure 2 and Figure 3 As shown, the second oiling actuator includes a second oiling actuator 11, a second oiling arm 12 mounted on the second oiling actuator 11, and a second oiling head 13 mounted on the second oiling arm 12 for oiling the lead wheel mounted on the lifting motor. The second oiling actuator 11 controls the rotation of the second oiling arm 12. The second oiling actuator 11 is fixedly connected to the lower end of the second telescopic arm body 7. One end of the second oiling arm 12 is fixedly connected to the output end of the second oiling actuator 11. The second oiling head 13 is fixedly mounted on the other end of the second oiling arm 12. The second oiling actuator 11 controls the rotation of the second oiling arm 12 and the second oiling head 13, enabling the second oiling head 13 to rotate above and away from the lead wheel. The rotation center line of the second oiling arm 12 is a vertical line.
[0031] After applying oil to the drive gear teeth of the lifting motor, the operator installs the threaded wheel onto the drive gear, connecting one end of the first steel wire. The oiling device then resumes operation. The second oiling actuator 11 rotates the second oiling arm 12, positioning it above the threaded wheel. The second telescopic actuator 6 then extends, bringing the second oiling head 13 closer to the threaded wheel below. The lifting motor is then powered on, and the drive gear rotates the threaded wheel. As the threaded wheel winds the first steel wire, the second oiling head 13 applies grease to the surfaces of both the threaded wheel and the first steel wire, ensuring the entire circumference of the threaded wheel is coated. After the oiling device resets, the second oiling head 13 moves away from the threaded wheel, allowing the second steel wire to be wound onto it.
[0032] In this embodiment, the first oiling actuator 8 is a cylinder, and the second oiling actuator 11 is a rotary cylinder. The pneumatic drive and control methods can avoid grease fires caused by electronic control, resulting in higher safety.
[0033] The oiling device with the above structure can easily control the grease application time and amount. The motor oiling mechanism and the wire wheel oiling mechanism are integrated together and executed separately by PLC control. It has a high degree of integration, small overall size, and reduces space waste.
[0034] like Figure 1 As shown, a first conveying device and a second conveying device are provided on the frame 1. Two wire winding fixtures 3 are provided. The second conveying device is provided with a lifting device 2 for controlling the lifting and lowering of one of the wire winding fixtures 3. The first conveying device and the second conveying device extend from the oiling station to the screw assembly station. The first conveying device is located above the second conveying device. The first conveying device is used to control the other wire winding fixture 3 to move between the oiling station and the screw assembly station. The oiling station and the screw assembly station are on the same straight line parallel to the second direction. The second direction is horizontal and perpendicular to the first direction.
[0035] In this embodiment, the first conveying device and the second conveying device are synchronous belt conveying mechanisms. The lifting device 2 mainly consists of a cylinder and a bracket set on the upper end of the cylinder. The wire winding fixture 3 is installed on the bracket. The lifting and lowering of the bracket and the wire winding fixture 3 on it are realized by the extension and retraction of the cylinder.
[0036] After the wire winding wheel on the wire winding fixture 3 at the oiling station is oiled and wound, two steel wires are wound around the wire winding wheel. Then, the oiled wire winding wheel cover is installed on the lifting motor. Then, the lifting device 2 operates to lower the wire winding fixture 3 (which does not have a lifting motor installed) located at the screw assembly station. Then, the first conveying device transports the wire winding fixture 3 at the oiling station to the screw assembly station. At the same time, the second conveying device transports the lifting device 2 and the wire winding fixture 3 on it to the oiling station. Then, the lifting device 2 controls the wire winding fixture 3 to rise. Then, the lifting motor that needs to be oiled can be installed on the wire winding fixture 3 located at the oiling station. The lifting motor and the wire winding wheel cover can be assembled on the wire winding fixture 3 that has been moved to the screw assembly station.
[0037] The above structure enables the two wire winding fixtures to move alternately, achieving automatic product handling. It reduces the need for operators, has a high degree of automation, and effectively connects the wire winding oiling and screw installation steps, resulting in high production efficiency.
[0038] like Figure 1 and Figure 4 As shown, the screw mounting device includes a fixed frame 14 mounted on a frame 1, an electric screwdriver 15, a lifting mechanism 16 connected to the electric screwdriver 15 and used to control the vertical movement of the electric screwdriver 15, a first position control mechanism 17 connected to the lifting mechanism 16 and used to control the horizontal linear movement of the lifting mechanism 16, and a second position control mechanism 18 connected to the first position control mechanism 17 and used to control the horizontal linear movement of the first position control mechanism 17. The second position control mechanism 18 is mounted on the fixed frame 14. When the first position control mechanism 17 moves the lifting mechanism 16, the direction of movement is parallel to a second direction. When the second position control mechanism 18 moves the first position control mechanism 17, the direction of movement is parallel to the first direction. The power output end of the first position control mechanism 17 is connected to the lifting mechanism 16, the power output end of the lifting mechanism 16 is connected to a washer, and the power output end of the second position control mechanism 18 is connected to the first position control mechanism 17.
[0039] In this embodiment, the lifting mechanism 16 mainly includes a cylinder, and the first position control mechanism 17 and the second position control mechanism 18 are linear modules.
[0040] The electric screwdriver 15 is connected to the screw feed tube, which is used to feed screws into the electric screwdriver 15. The outlet of the electric screwdriver 15 is equipped with a sensor, which is used to detect the number of screws during installation. It can achieve 100% screw quantity detection. The screw installation torque can be detected by the electric screwdriver 15, and the screw installation depth can be detected by the displacement sensor.
[0041] After a portion of both the first and second steel wires are wound onto the winding wheel, the first and second steel wires should not be in contact under normal conditions. If the first and second steel wires come into contact, it indicates that the wires are not properly assembled, there is twisting, and the winding is unqualified. Therefore, the winding device for the automotive window regulator of this invention also includes a power-on / off mechanism installed on the frame 1. The power-on / off mechanism detects the winding status and whether the first and second steel wires are properly assembled. The power-on / off mechanism mainly includes a first conductive plate, a second conductive plate, an alarm, and a power supply. The first and second conductive plates are respectively connected to the positive and negative terminals of the power supply. The first conductive plate is used to contact the first steel wire, and the second conductive plate is used to contact the second steel wire. The alarm is installed between the first conductive plate and the positive terminal of the power supply or between the second conductive plate and the negative terminal of the power supply. If the first and second steel wires come into contact and there is twisting, the power-on / off mechanism forms a circuit and generates current. The alarm is then activated, alerting the operator that the steel wires are not properly assembled. If the alarm does not sound during the assembly process, it means that the steel wire is assembled in place and there is no problem of cross-twisting.
[0042] The specific process of winding automotive window regulator wire using the above-described automotive window regulator wire winding equipment is as follows:
[0043] S1. Fix the lifting motor to the wire winding fixture 3 located at the oiling station;
[0044] S2. The oiling device applies oil to the tooth surface of the lifting motor;
[0045] S3. Install the lead wheel on the lifting motor;
[0046] S4. The oiling device applies oil to the wire wheel, while the wire wheel winds the first steel wire.
[0047] S5. Wind the second steel wire onto the wire wheel;
[0048] S6. The winding status is detected by the power-on / off mechanism;
[0049] S7. Install the screw wheel cover onto the lifting motor;
[0050] S8. Move the wire winding fixture 3 located at the oiling station to the screw assembly station;
[0051] S9. Assemble the lifting motor and the lead wheel cover.
[0052] In step S2 above, after the lifting motor is installed, the oiling device automatically starts working. The first telescopic actuator 4 and the first oiling actuator 8 extend, and the first oiling head 10 approaches the drive gear of the lifting motor. The lifting motor is powered on and the drive gear rotates. Then the first oiling head 10 can apply grease to the surface of the drive gear, so that the entire circumference of the drive gear is coated with grease.
[0053] In step S3 above, after the oiling of the drive gear teeth of the lifting motor is completed, the operator installs the lead wheel on the drive gear, and the lead wheel is connected to one end of the first steel wire.
[0054] In step S4 above, the oiling device starts working again. The second oiling actuator 11 drives the second oiling arm 12 to rotate, so that the second oiling arm 12 rotates to the top of the wire wheel. Then the second telescopic actuator 6 extends, and the second oiling head 13 approaches the wire wheel below. Then the lifting motor is powered on and runs, driving the gear to drive the wire wheel to rotate. While the wire wheel is winding the first steel wire, the second oiling head 13 can apply grease to the surface of the wire wheel and the first steel wire, so that the entire circumference of the wire wheel is coated with grease.
[0055] In step S5 above, after the oiling device is reset, the second oiling head 13 moves away from the wire wheel, and then the operator can wind the second steel wire onto the wire wheel.
[0056] In step S6 above, the power-on / off mechanism detects the winding state, checking whether the first and second steel wires are properly assembled. If the first and second steel wires are in contact, indicating cross-twisting, the power-on / off mechanism creates a circuit and generates current. The alarm is then activated, alerting the operator that the steel wires are not properly assembled, indicating a defective product assembly. If the alarm does not sound during assembly, it indicates that the steel wires are properly assembled and there is no cross-twisting issue, allowing the next step to proceed.
[0057] In step S7 above, after the wire wheel on the wire winding fixture 3 located at the oiling station is oiled and wound, two steel wires are wound on the wire wheel. Then, the wire wheel cover after oiling is installed on the lifting motor, and the wire wheel cover covers the wire wheel below.
[0058] In step S8 above, the lifting device 2 operates to lower the wire winding fixture 3 (which is not equipped with a lifting motor) located at the screw assembly station. Then, the first conveying device transports the wire winding fixture 3 located at the oiling station to the screw assembly station. At the same time, the second conveying device transports the lifting device 2 and the wire winding fixture 3 on it to the oiling station. Then, the lifting device 2 controls the wire winding fixture 3 to rise. Then, the lifting motor that needs to be oiled can be installed on the wire winding fixture 3 located at the oiling station.
[0059] In step S9 above, the lifting motor and the screw wheel cover are assembled on the wire winding fixture 3 that has been moved to the screw assembly station. The screws are installed on the lifting motor and the screw wheel cover by the screw installation device to achieve a fixed connection between the lifting motor and the screw wheel cover.
[0060] The above-mentioned wire winding method for automotive window regulators has the same distinguishing technical features and effects as existing technologies and automotive window regulator wire winding equipment, which will not be elaborated here.
[0061] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.
Claims
1. A wire winding device for automotive window regulators, comprising a frame, characterized in that: It also includes an oiling device mounted on the frame for oiling the tooth surface and thread wheel of the lifting motor at the oiling station, a wire winding fixture for placing the lifting motor, and a screw mounting device mounted on the frame for screw mounting at the screw assembly station. The wire winding fixture is configured to move between the oiling station and the screw assembly station. After the oiling of the tooth surface and thread wheel of the lifting motor is completed, the wire winding fixture drives the lifting motor and the thread wheel and thread wheel cover mounted on the lifting motor to move to the screw assembly station. The oiling device includes an oiling bracket mounted on the frame, a first telescopic component mounted on the oiling bracket, a second telescopic component vertically mounted on the first telescopic component, a first oiling actuator, and a second oiling actuator mounted on the second telescopic component. The first telescopic component includes a first telescopic actuator and a first telescopic arm body disposed on the first telescopic actuator; the second telescopic component includes a second telescopic actuator and a second telescopic arm body disposed on the second telescopic actuator; the second telescopic actuator and the first oiling actuator are disposed on the first telescopic arm body; the second oiling actuator is disposed on the second telescopic arm body. The first oiling actuator includes a first oiling actuator that is retractable in the vertical direction, a first oiling arm disposed on the first oiling actuator, and a first oiling head disposed on the first oiling arm for oiling the tooth surface of the lifting motor. The second oiling actuator includes a second oiling actuator, a second oiling arm disposed on the second oiling actuator, and a second oiling head disposed on the second oiling arm and used to oil the lead wheel mounted on the lifting motor. The second oiling actuator is used to control the second oiling arm to rotate. The frame is equipped with a first conveying device and a second conveying device. Two wire winding fixtures are provided. The second conveying device is equipped with a lifting device for controlling the lifting and lowering of one of the wire winding fixtures. The first and second conveying devices extend from the oiling station to the screw assembly station. The first conveying device is located above the second conveying device. The first conveying device is used to control the other wire winding fixture to move between the oiling station and the screw assembly station.
2. The automotive window regulator wire winding device according to claim 1, characterized in that: The first conveying device and the second conveying device are synchronous belt conveying mechanisms.
3. The automotive window regulator wire winding device according to claim 1, characterized in that: The screw mounting device includes a fixed frame mounted on the frame, an electric screwdriver, a lifting mechanism connected to the electric screwdriver and used to control the electric screwdriver to move vertically, a first position control mechanism connected to the lifting mechanism and used to control the lifting mechanism to move linearly horizontally, and a second position control mechanism connected to the first position control mechanism and used to control the first position control mechanism to move linearly horizontally.
4. The automotive window regulator wire winding device according to any one of claims 1 to 3, characterized in that: The frame is equipped with a power-on / off mechanism, which detects the winding status and whether the first and second steel wires on the wire wheel are properly assembled.
5. The automotive window regulator wire winding device according to claim 4, characterized in that: The power-on / off mechanism includes a first conductive plate, a second conductive plate, an alarm, and a power supply. The first and second conductive plates are respectively connected to the positive and negative terminals of the power supply. The first conductive plate is used to contact the first steel wire, and the second conductive plate is used to contact the second steel wire. The alarm is set in the circuit between the first conductive plate and the positive terminal of the power supply or between the second conductive plate and the negative terminal of the power supply.