Overheat indicating circuit for a paper shredder and paper shredder

Abstract

The utility model discloses an overheat indicating circuit and paper shredder of paper shredder belongs to paper shredder technical field. Overheat indicating circuit includes mutual inductor, first rectifier unit, second rectifier unit, control unit and indicating unit, the input of first rectifier unit and the primary side coil of mutual inductor are connected in series between first power end and second power end, and the output of first rectifier unit is connected with the power end of motor, second rectifier unit is used for forming detection signal according to the current of mutual inductor and exports detection signal to control unit, control unit is used for forming first control signal when the value of detection signal is located in first preset range, indicating unit is used for the display of first mode according to first control signal. The utility model can promote the safety and reliability of paper shredder.

Description

Technical Field

[0001] This utility model relates to the field of paper shredder technology, and in particular to an overheating indicator circuit for a paper shredder and a paper shredder. Background Technology

[0002] Most DC motor paper shredders on the market do not have an overheat indicator function. The motor temperature controller is directly connected in series with the motor circuit. When the temperature controller is disconnected, there is no overheat signal connected to the microcontroller, and the machine cannot indicate overheating, resulting in low reliability and safety of the paper shredder. Utility Model Content

[0003] This invention provides an overheating indicator circuit for a paper shredder and a paper shredder in order to improve the safety and reliability of the paper shredder.

[0004] According to one aspect of the present invention, an overheating indicator circuit for a paper shredder is provided, comprising:

[0005] A current transformer and a first rectifier unit, wherein the input terminal of the first rectifier unit and the primary coil of the current transformer are connected in series between the first power supply terminal and the second power supply terminal, and the output terminal of the first rectifier unit is connected to the power supply terminal of the motor.

[0006] The second rectifier unit has a first terminal connected to the first terminal of the secondary winding of the current transformer, and a second terminal connected to the control unit. The second terminal of the secondary winding of the current transformer is grounded. The second rectifier unit is used to generate a detection signal based on the current provided by the current transformer and output the detection signal to the control unit.

[0007] The control unit is used to generate a first control signal when the value of the detection signal is within a first preset range;

[0008] An indicator unit, connected to the control unit, is used to display a first mode according to the first control signal.

[0009] Optionally, the second rectifier unit includes a first diode; the anode of the first diode is connected to the first end of the secondary winding of the current transformer, and the cathode of the first diode is connected to the control unit.

[0010] Optionally, the first rectifier unit includes a rectifier bridge, which includes a second diode, a third diode, a fourth diode, and a fifth diode;

[0011] The anode of the second diode is connected to the first power supply terminal, the cathode of the second diode is connected to the cathode of the third diode, the cathode of the second diode is connected to the first power supply terminal of the motor, the anode of the third diode is connected to the cathode of the fourth diode, the anode of the third diode is connected to the first terminal of the primary winding of the current transformer, the anode of the fourth diode is connected to the anode of the fifth diode, the anode of the fourth diode is connected to the second power supply terminal of the motor, and the cathode of the fifth diode is connected to the first power supply terminal.

[0012] Optionally, the indicating unit includes a light-emitting diode (LED), with the first terminal of the LED connected to the control unit and the second terminal of the LED grounded.

[0013] Optionally, the overheating indicator circuit of the shredder further includes a first resistor;

[0014] The first end of the first resistor is connected to the second end of the second rectifier unit, and the second end of the first resistor is connected to the control unit.

[0015] Optionally, the overheating indicator circuit of the shredder further includes a second resistor;

[0016] The first end of the second resistor is connected to the first end of the secondary coil of the current transformer, and the second end of the second resistor is connected to the second end of the secondary coil of the current transformer.

[0017] Optionally, the overheating indicator circuit of the shredder also includes a voltage regulator diode;

[0018] The cathode of the Zener diode is connected to the control unit, and the anode of the Zener diode is connected to the second end of the secondary coil of the current transformer.

[0019] Optionally, the overheating indicator circuit of the shredder further includes a first capacitor, a second capacitor, and a third resistor;

[0020] The first terminal of the first capacitor is connected to the first terminal of the second capacitor, the first terminal of the second capacitor is connected to the control unit, the second terminal of the first capacitor is connected to the second terminal of the second capacitor, and the second terminal of the second capacitor is connected to the second terminal of the secondary winding of the current transformer.

[0021] The first end of the third resistor is connected to the first end of the second capacitor, and the second end of the third resistor is connected to the second end of the second capacitor.

[0022] According to another aspect of the present invention, a paper shredder is provided, including an overheating indicator circuit for the paper shredder provided in any embodiment of the present invention.

[0023] Optionally, the shredder further includes: an overload detection circuit; the overheat indicator circuit is reused as the overload detection circuit;

[0024] The control unit is further configured to generate a second control signal when the value of the detection signal is within a second preset range; the indicator unit is further configured to display a second mode according to the second control signal.

[0025] The technical solution of this utility model embodiment includes an overheating indicator circuit in the paper shredder. This overheating indicator circuit comprises a current transformer, a first rectifier unit, a second rectifier unit, a control unit, and an indicator unit. When shredding is performed and the motor cannot start normally, the control unit receives a detection signal transmitted by the second rectifier unit. If the detection signal is within a first preset range, the control unit controls the indicator unit to display a first mode, indicating that the motor is in an overheated state. When shredding is performed and the motor can start normally, the control unit receives a detection signal transmitted by the second rectifier unit. If the detection signal is not within the first preset range, the control unit controls the indicator unit to display a different mode than the first mode, indicating that the motor is not in an overheated state. Therefore, the motor status can be determined through the indicator unit's display, improving the safety and reliability of the paper shredder.

[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the overheating indicator circuit of a paper shredder provided for an embodiment of this utility model;

[0029] Figure 2 A schematic diagram of the overheating indicator circuit of another paper shredder provided for an embodiment of this utility model;

[0030] Figure 3 A schematic diagram of the overheating indicator circuit of another paper shredder provided for an embodiment of this utility model;

[0031] Figure 4 This is a structural schematic diagram of a paper shredder provided for an embodiment of the present utility model. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention 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 invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and their variations, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] This utility model embodiment provides an overheating indicator circuit for a paper shredder. Figure 1 A schematic diagram of an overheat indicator circuit for a paper shredder, provided as an embodiment of this utility model, is shown below. Figure 1 The overheating indication circuit of the paper shredder includes a current transformer L1, a first rectifier unit 10, a second rectifier unit 20, a control unit 30, and an indication unit 40.

[0035] The input terminal of the first rectifier unit 10 and the primary winding of the current transformer L1 are connected in series between the first power supply terminal AC_L and the second power supply terminal AC_N. The output terminal of the first rectifier unit 10 is connected to the power supply terminal of the motor 100. The first terminal of the second rectifier unit 20 is connected to the first terminal of the secondary winding of the current transformer L1, and the second terminal of the second rectifier unit 20 is connected to the control unit 30. The second terminal of the secondary winding of the current transformer L1 is grounded. The second rectifier unit 20 is used to generate a detection signal based on the current provided by the current transformer L1 and output the detection signal to the control unit 30. The control unit 30 is used to generate a first control signal when the value of the detection signal is within a first preset range. The indicator unit 40 is connected to the control unit 30 and is used to display a first mode based on the first control signal.

[0036] The current transformer L1 is an electrical device operating on the principle of electromagnetic induction. Its core function is to convert high voltage and large current into low voltage and small current at a fixed ratio to facilitate measurement, protection, and control of the power system. The first power supply terminal AC_L and the second power supply terminal AC_N are used to input AC voltage, such as 220V AC voltage. The motor 100 can be a DC motor. The first rectifier unit 10 is used to convert the AC voltage into DC voltage to ensure the normal operation of the motor 100. The second rectifier unit 20 is used to convert the AC voltage output from the secondary coil of the current transformer L1 into a unidirectional DC voltage, providing a positive pulse DC current for subsequent circuits (such as the control unit 30). The first preset range is the voltage range characterizing overheating of the motor 100. The first mode display can be a flashing display.

[0037] The overheat indicator circuit of this shredder is suitable for shredders equipped with a temperature controller, which is connected in series in the power supply circuit of the motor 100, and the control terminal of the temperature controller is connected to the control unit 30. Figure 1 The connection relationship of the thermostat is not shown in detail.

[0038] Specifically, the overheating indicator circuit of the paper shredder works as follows: During the shredding operation, the first rectifier unit 10 converts the AC voltage transmitted from the first power supply terminal and the second power supply terminal into DC voltage to power the motor 100. If the motor 100 can start normally, it indicates that the temperature controller is in the conducting state. At this time, the primary coil of the current transformer L1 generates a load current. According to the principle of electromagnetic induction, the secondary coil will induce an AC current proportional to that of the primary coil. Therefore, when the current of the motor 100 increases abnormally, the induced current in the primary coil will also increase synchronously. The second rectifier unit 20 further converts the AC current in the secondary coil into DC current, forming a detection signal that is transmitted to the control unit 30. At this time, the control unit 30 can control the indicator unit 40 to display a different state from the first mode display when the voltage change of the detection signal is not within the first preset range, so as to indicate that the motor 100 is not overheating.

[0039] If the motor 100 cannot start normally, it means that the temperature controller is in the off state. At this time, there is no current in the primary and secondary coils of the current transformer L1. Therefore, after the detection signal is generated by the second rectifier unit 20 and transmitted to the control unit 30, the control unit 30 detects that the voltage change of the detection signal is within the first preset range, and then outputs the first control signal to the indicator unit 40. The indicator unit 40 responds to the first control signal to display the first mode to indicate that the motor 100 is currently overheating.

[0040] It is understood that the display mode of the indicator unit 40 when the motor 100 is overheating is different from the display mode of the indicator unit 40 when the motor 100 is not overheating. For example, the display mode of the indicator unit 40 when the motor 100 is overheating can be a flashing mode, and the display mode of the indicator unit 40 when the motor 100 is not overheating can be a constant-on mode.

[0041] In other words, according to the technical solution of this utility model embodiment, when the user performs a shredding operation, if the motor 100 can start normally, the control unit 30 will receive an overheating signal and can determine that the motor 100 is not overheating by observing the voltage change; if the motor 100 cannot start normally (i.e., the motor is overheating and the thermostat is disconnected), the control unit 30 can determine that the motor is overheating and thus indicate the overheating status through the indicator unit 40. In other words, the display status of the indicator unit 40 allows for a direct visual assessment of whether the motor 100 is overheating.

[0042] The technical solution of this utility model embodiment includes an overheating indicator circuit in the paper shredder. This overheating indicator circuit comprises a current transformer L1, a first rectifier unit 10, a second rectifier unit 20, a control unit 30, and an indicator unit 40. When shredding is performed and the motor 100 cannot start normally, the control unit 30 receives a detection signal transmitted by the second rectifier unit 20. If the detection signal is within a first preset range, the control unit 30 controls the indicator unit 40 to display a first mode, indicating that the motor 100 is in an overheated state. When shredding is performed and the motor 100 can start normally, the control unit 30 receives a detection signal transmitted by the second rectifier unit 20. If the detection signal is not within the first preset range, the control unit 30 controls the indicator unit 40 to display a different mode than the first mode, indicating that the motor 100 is not in an overheated state. Therefore, the state of the motor 100 can be determined through the display of the indicator unit 40, improving the safety and reliability of the paper shredder.

[0043] Figure 2 A schematic diagram of the overheat indicator circuit for another paper shredder provided in this embodiment of the present invention is shown below. Figure 2 Based on the above embodiments, optionally, the second rectifier unit 20 includes a first diode D1; the anode of the first diode D1 is connected to the first end of the secondary side coil of the current transformer L1, and the cathode of the first diode D1 is connected to the control unit 30.

[0044] The control unit 30 can be a microcontroller. The first diode D1 is specifically used to rectify the AC current of the secondary coil of the current transformer L1 into unidirectional DC current, providing a positive pulse DC current for the microcontroller.

[0045] See also Figure 2Optionally, the first rectifier unit 10 includes a rectifier bridge, which includes a second diode D2, a third diode D3, a fourth diode D4, and a fifth diode D5.

[0046] In this configuration, the anode of the second diode D2 is connected to the first power supply terminal AC_L, the cathode of the second diode D2 is connected to the cathode of the third diode D3, and the cathode of the second diode D2 is connected to the first power supply terminal of the motor 100. The anode of the third diode D3 is connected to the cathode of the fourth diode D4, and the anode of the third diode D3 is connected to the first terminal of the primary winding of the current transformer L1. The anode of the fourth diode D4 is connected to the anode of the fifth diode D5, and the anode of the fourth diode D4 is connected to the second power supply terminal of the motor 100. The cathode of the fifth diode D5 is connected to the first power supply terminal AC_L. By setting up a rectifier bridge, the rectifier bridge simultaneously rectifies the positive and negative half-cycles of the AC current through four diodes, thus achieving high energy utilization. Furthermore, due to full-wave rectification, the output voltage waveform is smoother, the ripple voltage is smaller, and therefore the voltage stability is high.

[0047] See also Figure 2 Optionally, the indicator unit 40 includes a light-emitting diode LD1, the first terminal of which is connected to the control unit 30, and the second terminal of which is grounded.

[0048] It is understandable that LED LD1 can be connected to control unit 30 through a current-limiting resistor. LED LD1 can respond to different control signals output by control unit 30 to display in different modes, and the display status is different in different modes.

[0049] Figure 3 A schematic diagram of the overheat indicator circuit for another paper shredder provided in this embodiment of the present invention is shown below. Figure 3 Based on the above embodiments, optionally, the overheating indicator circuit further includes a first resistor R1; the first end of the first resistor R1 is connected to the second end of the second rectifier unit 20, and the second end of the first resistor R1 is connected to the control unit 30. The first resistor R1 is used for current limiting to prevent damage to subsequent components.

[0050] See also Figure 3 Optionally, the overheat indication circuit further includes a second resistor R2; the first end of the second resistor R2 is connected to the first end of the secondary winding of the current transformer L1, and the second end of the second resistor R2 is connected to the second end of the secondary winding of the current transformer L1. That is, the second resistor R2 is connected in parallel across the two ends of the secondary winding of the current transformer L1 to protect the secondary winding of the current transformer L1 when the secondary winding of the current transformer L1 is open-circuited.

[0051] See also Figure 3Optionally, the overheat indication circuit also includes a Zener diode ZD1; the cathode of the Zener diode ZD1 is connected to the control unit 30, and the anode of the Zener diode ZD1 is connected to the second terminal of the secondary winding of the current transformer L1. The Zener diode ZD1 is used to clamp the voltage to prevent excessive voltage from damaging the control unit 30 (microcontroller).

[0052] See also Figure 3 Optionally, the overheat indicator circuit also includes a first capacitor C1, a second capacitor C2, and a third resistor R3.

[0053] Specifically, the first terminal of the first capacitor C1 is connected to the first terminal of the second capacitor C2, the first terminal of the second capacitor C2 is connected to the control unit 30, the second terminal of the first capacitor C1 is connected to the second terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to the second terminal of the secondary winding of the current transformer L1. The first capacitor C1 and the second capacitor C2 are used for filtering, converting the pulse current into a stable DC current. The first terminal of the third resistor R3 is connected to the first terminal of the second capacitor C2, and the second terminal of the third resistor R3 is connected to the second terminal of the second capacitor C2. The third resistor R3 is used for discharging to prevent the first capacitor C1 and the second capacitor C2 from continuously charging.

[0054] This utility model embodiment also provides a paper shredder, including the overheat indicator circuit of the paper shredder provided in any of the above embodiments. Therefore, this paper shredder has the same beneficial effects.

[0055] Figure 4 A schematic diagram of a paper shredder structure provided for an embodiment of this utility model is shown below. Figure 4 The shredder 200 also includes an overload detection circuit; the overheat indicator circuit 300 is reused as an overload detection circuit.

[0056] Specifically, the control unit 30 is further configured to generate a second control signal when the value of the detected signal is within a second preset range; the indication unit 40 is further configured to display a second mode according to the second control signal. The second mode display can be a constantly lit mode, the shredder 200 can be a DC shredder, and the second preset range is a voltage range indicating that the motor 100 has not overheated. For example, the minimum voltage value in the second preset range is greater than the maximum voltage value in the first preset range.

[0057] Specifically, the working principle of the paper shredder is as follows: When the user performs a shredding operation, if the motor 100 fails to start normally, the control unit 30 receives the detection signal transmitted by the second rectifier unit 20, and when the detection signal is within a first preset range, outputs a first control signal to the indicator unit 40. The indicator unit 40 responds to the first control signal and displays a first mode to indicate that the motor 100 is overheating / overloaded. That is, here, the overheating signal is multiplexed as an overload signal.

[0058] If the motor 100 can start normally, the control unit 30 receives the detection signal transmitted by the second rectifier unit 20, and when the detection signal is within the second preset range, it outputs the second control signal to the indicator unit 40. The indicator unit 40 responds to the second control signal to display the second mode to indicate that the motor 100 is not overheated / overloaded.

[0059] In other words, when a user performs a shredding operation, if the motor 100 can start normally, the control unit 30 will receive an overload signal, and the change in voltage will indicate that the motor is not overheating. If the motor 100 cannot start normally, the control unit 30 will not receive an overload signal, and therefore the lack of voltage change will indicate that the motor is overheating.

[0060] The technical solution provided by this embodiment of the utility model reuses the overheat indicator circuit 300 as an overload detection circuit, or in other words, reuses the overload detection circuit as an overheat indicator circuit 300. This allows the DC shredder to detect overload (excessive shredding in a single operation) voltage signals. Voltage fluctuations indicate that the motor 100 can operate normally and is not overheated; conversely, no voltage fluctuations indicate that the motor 100 is overheated. In summary, the shredder provided by this embodiment of the utility model, by reusing the overheat indicator circuit 300 and the overload detection circuit, avoids the problem of most shredders lacking overheat indication functionality, requiring an additional connector to the temperature controller and a separate overheating component on the printed circuit board (PCBA), along with the need for a microcontroller to determine overheating and provide an overheat indication function. This avoids the increased complexity and cost associated with adding a heat indicator circuit to the shredder. In other words, the paper shredder provided in this embodiment of the invention can provide an overheat indication, simplify the paper shredder's circuitry, and reduce costs.

[0061] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0062] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An overheating indicator circuit for a paper shredder, characterized in that, include: A current transformer and a first rectifier unit, wherein the input terminal of the first rectifier unit and the primary coil of the current transformer are connected in series between the first power supply terminal and the second power supply terminal, and the output terminal of the first rectifier unit is connected to the power supply terminal of the motor. The second rectifier unit has a first terminal connected to the first terminal of the secondary winding of the current transformer, and a second terminal connected to the control unit. The second terminal of the secondary winding of the current transformer is grounded. The second rectifier unit is used to generate a detection signal based on the current provided by the current transformer and output the detection signal to the control unit. The control unit is used to generate a first control signal when the value of the detection signal is within a first preset range; An indicator unit, connected to the control unit, is used to display a first mode according to the first control signal.

2. The overheating indicator circuit for the paper shredder according to claim 1, characterized in that, The second rectifier unit includes a first diode; the anode of the first diode is connected to the first end of the secondary winding of the current transformer, and the cathode of the first diode is connected to the control unit.

3. The paper shredder overheating indication circuit of claim 1, wherein, The first rectifier unit includes a rectifier bridge, which includes a second diode, a third diode, a fourth diode, and a fifth diode; The anode of the second diode is connected to the first power supply terminal, the cathode of the second diode is connected to the cathode of the third diode, the cathode of the second diode is connected to the first power supply terminal of the motor, the anode of the third diode is connected to the cathode of the fourth diode, the anode of the third diode is connected to the first terminal of the primary winding of the current transformer, the anode of the fourth diode is connected to the anode of the fifth diode, the anode of the fourth diode is connected to the second power supply terminal of the motor, and the cathode of the fifth diode is connected to the first power supply terminal.

4. The paper shredder overheating indication circuit of claim 1, wherein, The indicator unit includes a light-emitting diode (LED), with the first terminal of the LED connected to the control unit and the second terminal of the LED grounded.

5. The paper shredder overheating indication circuit of claim 1, wherein, It also includes the first resistor; The first end of the first resistor is connected to the second end of the second rectifier unit, and the second end of the first resistor is connected to the control unit.

6. The paper shredder overheating indication circuit of claim 1, wherein, It also includes a second resistor; The first end of the second resistor is connected to the first end of the secondary coil of the current transformer, and the second end of the second resistor is connected to the second end of the secondary coil of the current transformer.

7. The overheating indicator circuit for the paper shredder according to claim 1, characterized in that, It also includes Zener diodes; The cathode of the Zener diode is connected to the control unit, and the anode of the Zener diode is connected to the second end of the secondary coil of the current transformer.

8. The paper shredder overheating indication circuit of claim 1, wherein, It also includes a first capacitor, a second capacitor, and a third resistor; The first terminal of the first capacitor is connected to the first terminal of the second capacitor, the first terminal of the second capacitor is connected to the control unit, the second terminal of the first capacitor is connected to the second terminal of the second capacitor, and the second terminal of the second capacitor is connected to the second terminal of the secondary winding of the current transformer. The first end of the third resistor is connected to the first end of the second capacitor, and the second end of the third resistor is connected to the second end of the second capacitor.

9. A paper shredder characterized by The shredder includes an overheating indicator circuit as described in any one of claims 1-8.

10. The paper shredder of claim 9, wherein, Also includes: Overload detection circuit; the overheat indicator circuit is reused as the overload detection circuit; The control unit is further configured to generate a second control signal when the value of the detection signal is within a second preset range; the indicator unit is further configured to display a second mode according to the second control signal.

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