Method for controlling excessive pressure in oral care devices

Abstract

A method for controlling overpressure in an electric oral care device having a treatment head equipped with at least one functional element driven by a motor. The method comprises detecting a stimulus and energizing the motor, setting a baseline current, and executing a repeating overpressure detection control loop, which includes measuring the instantaneous current draw of the motor; adding an increment value to the baseline current or subtracting a decrement value from the baseline current to generate a dynamically adjusted baseline current; determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold to detect the occurrence of overpressure; and performing a corrective action in response to the detected occurrence of overpressure.

Description

Technical Field

[0001] The present disclosure relates to an electric oral care appliance, such as an electric toothbrush, having a pressure control system, and a method for controlling the pressure of such an appliance.

Background Art

[0002] Personal care and grooming have become an important part of many consumers' lifestyles today. For example, modern personal care products, such as oral care appliances, rely on electricity to provide the high-quality results expected by consumers. Such oral care electric appliances have technically advanced features, and the increasing use of electric toothbrushes reflects the growing awareness among consumers of the advantages provided by electric toothbrushes, such as convenience, effectiveness, and health benefits. Compared with conventional manual toothbrushes, electric toothbrushes can provide excellent brushing results.

[0003] Typically, an electric toothbrush includes a toothbrush handle having a battery and an electric motor housed therein, and a replaceable toothbrush head removably attached to the toothbrush handle. The toothbrush head includes a cleaning element, such as a tuft of bristles, located at the free end of the toothbrush head, and a movable functional element, such as a bristle holder. The motor in the toothbrush handle controls the movement of the functional element and moves the cleaning element. Such movements can include, for example, up-and-down movement, left-and-right movement, movement in a circular movement pattern, i.e., vibration, rotation, etc. In some electric toothbrushes, the bristle head is designed to vibrate.

[0004] While electric toothbrushes can offer excellent advantages, a common potential problem with them is excessive pressure, or overpressure. Overpressure generally occurs when the user operating the electric toothbrush applies a high level of pressure (typically applied by non-electric toothbrushes) during brushing. Since electric toothbrushes are not designed to be used with high pressure during brushing, such excessive pressure can lead to poor cleaning results. Furthermore, if the user applies excessive pressure for a considerable period of time, it can damage the user's gums. Therefore, it is necessary to monitor—and prevent—the user from applying excessive pressure to the toothbrush bristles so that the force applied by the user during brushing remains below undesirable and potentially harmful levels.

[0005] Various pressure sensing devices are known for use in electric (and manual) toothbrushes to determine and / or limit the pressure applied to the bristles during brushing. For example, as is commonly understood in the art, the current drawn from the electric motor in the toothbrush changes in proportion to the amount of pressure applied to the brush head. Below, several prior art attempts to address the problem of overpressure in electric toothbrushes are summarized herein.

[0006] U.S. Patent No. 5,784,742 relates to an electric toothbrush having an adaptive load sensor. The toothbrush includes a brush head that is vibrated by a drive assembly. The load sensor monitors the current drawn by the drive assembly to determine the mechanical load to which the toothbrush is subjected. The load sensor assembly generates an adaptive threshold signal representing the instantaneous maximum pressure load. If the detected load voltage exceeds the adaptive threshold signal, the load sensor assembly cuts off power to the drive assembly and generates an alarm signal to warn the user that the toothbrush is being overloaded.

[0007] U.S. Patent No. 9,687,329 relates to an electric toothbrush comprising a brush head, a motor, and a controller. The controller drives the motor via a power module and detects the motor current to drive the motor in pulse-start mode when the detected current exceeds a predetermined current threshold. Pulse-start mode causes a pulsating motion of the bristle tuft, prompting the person to release the brush pressure. If the brush pressure does not change, the controller disables the motor and warns the person.

[0008] U.S. Patent No. 10,561,480 (B2) relates to a toothbrush that includes a control assembly that monitors current draw by a DC motor and adjusts the current applied to the motor based on the current draw. The motor control unit may alert the user when the applied force exceeds a threshold and / or adjust the motor's operation accordingly. The threshold may be a change in current from a no-load or normal load current value (e.g., current delta). Thus, the toothbrush tracks the motor's operation or the delta change from no-load current draw. The initial current draw is assumed to represent no-load current draw. If the initial load is greater than an acceptable no-load condition, a default or historical no-load condition is applied to initialize the measurement. To track the current draw, the sensing module tracks the mechanical load experienced by the bristles by tracking the current applied to the motor. The current drawn by the motor is proportional to the load (e.g., the force required to move the bristles), and as the load increases, the current drawn by the motor also increases. If the pressure exceeds a threshold, the control assembly provides an output to the user, such as vibration of the brush handle, activation of one or more lights, stopping of the motor, generation of a buzzer or other audible sound, or generation of stutter motion by the brush tip.

[0009] One challenge in overpressure detection in electric toothbrushes is setting an appropriate threshold for the occurrence of overpressure. Current draw can naturally vary depending on the specific brush head and its mechanical properties, including the frictional force present between its mechanical elements and the degree of wear. Therefore, for each brushing event, it is necessary to dynamically set and adjust the overpressure threshold, taking into account the various environments described herein. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] U.S. Patent No. 5,784,742 [Patent Document 2] U.S. Patent No. 9,687,329 [Patent Document 3] U.S. Patent No. 10,561,480 (B2) [Overview of the project] [Problems that the invention aims to solve]

[0011] Accordingly, this disclosure addresses the problem of overpressure in electric oral care devices, such as electric toothbrushes. This disclosure relates to an electric oral care device having an overpressure detection system, which is configured to monitor motor current draw, detect overpressure events, automatically perform corrective actions, and at the same time avoid the shortcomings of prior art devices and systems. This disclosure also relates to a method for controlling overpressure in an electric oral care device. [Means for solving the problem]

[0012] This disclosure provides an oral care device comprising a pressure control system that does not consider the initial current draw of the motor to represent a no-load state. Instead, the pressure control system described herein calculates a dynamically adjusted baseline current. This disclosure further provides a method for controlling overpressure of an electric oral care device.

[0013] In one embodiment, this disclosure provides an oral care device, such as a toothbrush, comprising a handle that houses a battery electrically communicating with an electric motor having a motor shaft. The toothbrush has a motion transmission unit operably connected to the motor shaft. The toothbrush includes a treatment head that is operably in communication with the motion transmission unit and has at least one functional element driven by the motion transmission unit. As is known in the art, the treatment head can be constructed and configured to be attachable to and detachable from the handle.

[0014] The toothbrush further includes a pressure control system electrically connected to the motor. The pressure control system comprises a controller (e.g., a microcontroller) configured to detect a stimulus and energize the motor, set a baseline current, and repeatedly execute an overpressure detection control loop to detect the occurrence of overpressure. The microcontroller may be configured to measure the current draw of the motor and set the baseline current to the measured current draw in order to set the baseline current. Alternatively, the microcontroller may be configured to set the baseline current to a predetermined value. In one embodiment, the predetermined value may be about 100 mA to about 600 mA.

[0015] The overpressure detection control loop includes measuring the instantaneous current draw of the motor; adding an increment value to the baseline current or subtracting a decrement value from the baseline current to generate a dynamically adjusted (calculated) baseline current; determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold to detect the occurrence of overpressure; and causing the oral care device to perform corrective actions in response to the detected overpressure. In one embodiment, the microcontroller is configured to detect whether the overpressure has been resolved. The overpressure detection control loop for detecting the occurrence of overpressure can be executed repeatedly every 1 to 1000 milliseconds, more specifically every 5 to 100 milliseconds. In one exemplary embodiment, the overpressure detection control loop is executed once every 10 milliseconds.

[0016] It can be beneficial for a dynamically adjusted baseline current to be the lower limit of the motor current. Many electric brush users tend to apply continuous load during brushing. While users may reduce pressure during brushing, this typically only occurs for relatively short periods. Therefore, since low-load conditions are significantly shorter than high-load conditions, the decrease in baseline current needs to occur much faster than the increase in baseline current. On the other hand, as long as a load is applied, the dynamically adjusted baseline current increases gradually at a slower rate until the baseline current and motor current are approximately equal.

[0017] Tests have shown that if the decrease of the dynamically adjusted baseline current is too slow, it may be difficult to achieve high accuracy when managing overvoltage. The rate of decrease of the dynamically adjusted baseline current can range from approximately 0.66 mA / sec to approximately 6000 mA / sec. In one exemplary embodiment, a rate of decrease of the dynamically adjusted baseline current of approximately 200 mA / sec (or higher) was found to be particularly advantageous. Conversely, the rate of increase of the dynamically adjusted baseline current can range from approximately 0.03 mA / sec to approximately 600 mA / sec. In one exemplary embodiment, the rate of increase of the dynamically adjusted baseline current is approximately 10 mA / sec.

[0018] Similarly, it is considered beneficial for the overpressure detection control loop to set the increment and decrement values ​​so that the decrement value is significantly larger than the increment value. The decrement value can be at least 10, 20, and 30 times larger than the increment value. For example, the decrement value may be about 0.66 mA to about 6 mA. In one exemplary embodiment, the decrement value is about 2 mA. The increment value may be about 0.03 mA to about 0.6 mA. In one exemplary embodiment, the increment value is about 0.1 mA.

[0019] The microcontroller can be configured to add a threshold to the dynamically adjusted baseline current in order to determine whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds the threshold. The threshold may include a high-load threshold indicating the motor's load state and a low-load threshold indicating the motor's low-load state.

[0020] If the difference between the instantaneous current draw and the dynamically adjusted baseline current is greater than or equal to a high load threshold, the corrective action may include configuring the motor to move at least one functional element at a second intensity different from the first intensity. The corrective action can be selected from the group consisting of decelerating the motor, generating an optical signal, generating a tactile signal, generating an acoustic signal, and any combination thereof.

[0021] Reducing the motor speed can cause the brush head, which has cleaning elements on it, to move (e.g., rotate or vibrate) at a reduced frequency or amplitude. In a vibrating toothbrush, the intensity of the vibration can be reduced. The microcontroller may be further configured to increase the motor speed back to its initial speed in response to detecting that the overpressure has been resolved. If no overpressure is detected, the microcontroller configures the motor to move at least one functional element at a first (i.e., "normal") intensity and to perform no corrective action.

[0022] The microcontroller can be configured to determine whether the difference between the instantaneous current draw and the dynamically adjusted baseline current is below a low-load threshold in order to detect whether the overpressure has been resolved. If the difference between the instantaneous current draw and the dynamically adjusted baseline current is below the low-load threshold, the microcontroller configures the motor to move at least one functional element at a first intensity.

[0023] In one embodiment, the microcontroller is configured to energize the motor by performing a stabilization phase (or step) in response to the detection of a stimulus. The stabilization phase allows the motor to reach its performance equilibrium. During the stabilization phase, the microcontroller delays the measurement of the current draw and the setting of the baseline current. The stabilization phase can last from about 500 milliseconds to about 5000 milliseconds, more specifically, from about 1000 milliseconds to about 3000 milliseconds. In one exemplary embodiment, the stabilization phase lasts for about 2000 milliseconds. The stabilization phase also allows the user to have sufficient time to apply pressure to the toothbrush cleaning element before the cleaning element begins to move while the toothbrush is applied to the user's teeth.

[0024] The current draw when no pressure is applied to the cleaning element (in a "no-load" state) can be measured and the overpressure threshold can be set to a predetermined value that exceeds the no-load current. However, most users of an electric toothbrush, of course, prefer that the toothbrush be operational when it is already in the user's mouth and pressure is applied to the cleaning element. If the user makes the electric toothbrush operational outside the user's mouth, the rapid movement of the cleaning element of the toothbrush (whether rotational vibration or vibration) will almost inevitably cause water and toothpaste to splash around it, which is a very undesirable event for the toothbrush user. Therefore, conventional techniques that rely on measurements in the no-load state are considered unreliable as they provide unsatisfactory results when implemented by an electric toothbrush.

[0025] For at least these reasons, the pressure control system of the oral care appliance disclosed herein does not consider the initial current draw of the motor to represent a no-load state. Instead, the algorithm implemented in the pressure control system of the present disclosure calculates a dynamically adjusted baseline current and determines whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a high-load threshold, thereby detecting the occurrence of overpressure.

[0026] According to the present disclosure, since the microcontroller does not measure current draw during the stabilization phase, if the user applies pressure to the cleaning element during the stabilization phase, the baseline is not set based on the no-load state. Instead, the microcontroller sets the baseline under a loaded state after the stabilization phase has elapsed and while the user is already applying pressure to the cleaning element of the toothbrush.

[0027] In another aspect, the present disclosure provides a method for controlling overpressure of an electric oral care appliance having a handle, a motor, and a treatment head having at least one functional element driven by the motor. The method includes detecting a stimulus, energizing the motor, setting a baseline current, and repeatedly executing an overpressure detection control loop. The step of setting the baseline current can be achieved by measuring the current draw of the motor and setting the baseline current to the measured current draw. Alternatively, setting the baseline current can be achieved by setting the baseline current to a predetermined value, for example, a value from about 100 mA to about 600 mA.

[0028] In one embodiment, the step of repeatedly executing the overpressure detection control loop is performed every 1 to 1000 milliseconds, more specifically, every 5 to 100 milliseconds. In one exemplary embodiment, the step of repeatedly executing the overpressure detection control loop is performed every 10 milliseconds. Optionally, the waiting period can be performed between the end of one loop and the start of the next loop according to the desired frequency and its period.

[0029] The overpressure detection control loop includes measuring the instantaneous current draw of the motor; adding an increment value to the baseline current or subtracting a decrement value from the baseline current to generate a dynamically adjusted baseline current; determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold to detect the occurrence of overpressure; and performing corrective actions in response to the detected overpressure.

[0030] The step of adding an increment value to the baseline current or subtracting a decrement value from the baseline current includes adding an increment value to the baseline current if the instantaneous current is greater than or equal to the baseline current, or subtracting a decrement value from the baseline current if the instantaneous current is less than the baseline current. In one embodiment, the decrement value is greater than the increment value. The decrement value can be at least 10, 20, and 30 times greater than the increment value. In one exemplary embodiment, the decrement value is about 2 mA. In one exemplary embodiment, the increment value is about 0.1 mA.

[0031] The step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold includes adding the threshold to the dynamically adjusted baseline current. The method may further include the step of determining whether the overvoltage has been resolved.

[0032] The method may further include a stabilization step, which is performed to energize the motor in response to the detection of a stimulus. The stabilization step may be delayed, during which the current draw of the motor is measured to set a baseline current, and may last for about 500 milliseconds to about 5000 milliseconds, more specifically, about 500 milliseconds to about 5000 milliseconds. In one exemplary embodiment, the stabilization step lasts for about 2000 milliseconds.

[0033] The step of causing an oral care device to perform a corrective action in response to the detection of overpressure includes causing the oral care device to perform a corrective action selected from the group consisting of slowing down the motor, generating an optical signal, generating a tactile signal, generating an acoustic signal, and any combination thereof. In one embodiment, the step of causing an oral care device to perform a corrective action in response to the detection of overpressure includes configuring the motor to move at least one functional element at a second intensity different from a first intensity. Moving at least one functional element at a second intensity may include slowing down the rotational speed of the motor. The method may further include the step of increasing the motor speed back to its initial speed in response to detecting that the overpressure has been resolved.

[0034] The step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold may include determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a high load threshold indicating a motor load state. Detecting whether the overpressure has been resolved may include determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current is less than a low load threshold indicating a motor low load state, in which case the motor is configured to move at least one functional element at a first intensity. [Brief explanation of the drawing]

[0035] The present invention will be described in more detail below with reference to various non-limiting embodiments and illustrative drawings. [Figure 1] This is a schematic side view of one embodiment of an oral care device equipped with an electric toothbrush. [Figure 2] Figure 1 is a schematic cross-sectional view of an electric toothbrush. [Figure 3] This is a flowchart of an algorithm implemented in one embodiment of a pressure control system used in oral care devices. [Modes for carrying out the invention]

[0036] In the context of this specification, the terms “treatment force” or “treatment pressure” (or simply “force” or “pressure” may be used interchangeably herein and mean the force applied to the treatment head in the treatment direction. In electric toothbrushes, the treatment direction is most typically the direction substantially perpendicular to the longitudinal axis of the toothbrush head. The total applied treatment force (i.e., forces applied in two or more directions) may be higher than the treatment force applied primarily in the treatment direction, but such treatment forces acting in directions other than the treatment direction are not considered because they are absorbed essentially in the bearings or by the elastic deformation of the oral care device.

[0037] Figure 1 illustrates an embodiment of an oral care device comprising an electric toothbrush 10 according to the present disclosure. The toothbrush 10 comprises a toothbrush handle 110 and a toothbrush head 120 that can be attached to and detached from the toothbrush handle 110. The toothbrush handle 110 has a first end 111, a second end 112 opposite to the first end 111, and a longitudinal axis 113 extending between the first end 111 and the second end 112 of the toothbrush handle 110. Similarly, the toothbrush head 120 has a first end 121, a second end 122 opposite to the first end 121, and a longitudinal axis 123 extending between the first end 121 and the second end 122 of the toothbrush head 120. When the toothbrush head 120 is attached to the toothbrush handle 110, the first end 111 of the toothbrush handle 110 and the first end 121 of the toothbrush head 120 come into contact with each other.

[0038] In some embodiments, when the toothbrush head 120 is attached to the toothbrush handle 110, the longitudinal axis 123 of the toothbrush head 120 may be substantially parallel to, or even coincide with, the longitudinal axis 113 of the toothbrush handle 110 (Figure 1). In other embodiments, when the toothbrush head 120 is attached to the toothbrush handle 110, the longitudinal axis 123 of the toothbrush head 120 and the longitudinal axis 113 of the toothbrush handle 110 may not be parallel to each other, and instead, an acute angle may be formed between them.

[0039] The toothbrush head 120 has at least one cleaning element 125 disposed at the second end 122 of the toothbrush head 120. In Figures 1 and 2, the head 120 has a plurality of tufts 125, each of which comprises a plurality of cleaning elements 126, such as bristles, fixed to a tuft carrier 124 mounted to drive the movement at the second 122 of the toothbrush head 120. During brushing, the tuft carrier 124 moves in a desired motion pattern, based on the design of the toothbrush 10, for example, a pattern including rotational vibration, a pattern including linear vibration, a pattern including pivotal vibration, or any combination thereof. Toothbrushes constructed for various vibrational (non-rotational) motions are also known in the art. For example, a power switch, such as an ON / OFF push button 160, can be conveniently positioned on the front surface 114 of the toothbrush handle 110.

[0040] As is known in the art, the toothbrush 10 may have a number of operating modes, each of which is characterized by the frequency and / or amplitude of movement (e.g., vibration, oscillating, rotating) of its functional elements, such as at least one cleaning element 125. Each mode may be designed to perform a specific function, such as daily cleaning brushing, light brushing, strong brushing, tongue cleaning, etc. The frequency of movement of at least one cleaning element 125 may be in the range of, for example, about 50 Hz to about 300 Hz.

[0041] Figure 2 shows a cross-sectional view of one embodiment of the toothbrush 10, in which the handle 120 houses, internally, an electrical energy source such as a battery 130 and an electric motor such as a direct-current (DC) motor 140 electrically connected to the battery 130. The motion transmission unit 150 is provided on both the toothbrush handle 110 and the toothbrush head 120 and includes an output shaft 151, which converts the continuous rotational motion of the motor into brushing motion of the tuft support 124 and cleaning element 125 and transmits it. For example, a controller such as a microcontroller 170 is operationally in communication with the motor 140.

[0042] The microcontroller 170 may include a processor such as one or more microprocessors, controllers, field programmable gate arrays (FPGAs), and application-specific integrated circuits (ASICs), and / or any preferred type of processor. The microcontroller 170 may also include memory (e.g., volatile memory, non-volatile memory) which stores machine-readable instructions corresponding to operations described, for example, with respect to a pressure control system, including performing functions described with respect to a stabilization stage and an overpressure detection control loop.

[0043] As previously described, the brushing motion may be selected based on the specific design of the oral care device, including the design of the motion transmission unit 150. In the exemplary embodiment of the electric toothbrush 10 illustrated in Figure 2, the motion transmission unit 150 comprises a mechanism including, for example, a bevel (or miter) gear 152, which provides the oscillating rotational motion of the tuft 125 comprising the cleaning element 126. However, other mechanisms and configurations known in the art can be used to produce the desired motion of the functional element 124 of the device. Similarly, the brush 10 can be driven using a known electric motor other than a DC motor.

[0044] As shown in diagram 300 of Figure 3, one embodiment of the pressure control system operates according to an algorithm that begins with the motor 140 being energized (at 310 in Figure 3). The microcontroller 170 first detects that the motor 140 is energized, for example, by the user activating an on / off switch (e.g., a push button) 160. In the exemplary embodiment illustrated in Figure 3, the microcontroller 170 is configured to perform a stabilization phase or step immediately after detecting that the motor 140 is energized (at 304). During the stabilization phase, no current draw measurements are taken to set the baseline current, for reasons at least described below.

[0045] Most users of electric toothbrushes typically prefer to enable the toothbrush when the functional element 124, equipped with a cleaning element 126 (on which toothpaste is applied), is already in the user's mouth. Doing so avoids the undesirable splashing of water and toothpaste that almost certainly occurs when the brush is turned on and the functional element (on which toothpaste is applied) begins to move outside the user's mouth. Users may begin brushing with low pressure and gradually increase the pressure to their normal (habitual) brushing pressure during the brushing process. Alternatively, users may begin brushing with normal brushing pressure from the moment they start brushing. These types of brushing behavior are difficult to specify and define definitively.

[0046] Simultaneously, immediately after the motor 140 is switched on, the initial current draw may be relatively high. Mechanical systems, as well as electronic equipment, may require a short period to warm up and reach a stable state. Therefore, it may be advantageous to delay taking measurements over the duration of the stabilization phase to avoid erroneous indications of excessive pressure based on the relatively high initial current draw. Accordingly, the microcontroller 170 may be configured not to measure the current draw and set the baseline current during the stabilization phase. The stabilization phase may last from about 500 milliseconds to about 5000 milliseconds, more specifically from about 1000 milliseconds to about 3000 milliseconds. In one exemplary embodiment, the duration of the stabilization phase is about 2000 milliseconds.

[0047] Therefore, the stabilization phase is intended to allow sufficient time for the motor 140 to reach its full voltage, enabling the user to place the toothbrush 10 in their mouth, position the toothbrush cleaning element 126 against their teeth, and begin applying pressure to the cleaning element 126. This avoids setting the baseline current under no-load conditions. As previously explained, measuring the motor current under no-load (or "unloaded") conditions is unreliable for the purpose of calculating the overpressure threshold. Conversely, measuring the motor current while the user is applying pressure to the toothbrush 10 in their mouth provides a realistic setting and a reliable basis for calculating the baseline current.

[0048] The microcontroller 170 measures the current draw of the motor 140 (at 306 in Figure 3) after the delay that occurred during the stabilization phase has elapsed, and (at 308) sets the baseline current to the initial current measurement. Alternatively, the microcontroller 170 can be configured to set the baseline current to a predetermined value, for example, in the range of approximately 100mA to approximately 600mA.

[0049] The microcontroller 170 initializes the overpressure detection control loop after the baseline current has been set. If the user has already applied pressure to the toothbrush head 120 (most commonly to avoid toothpaste splatter), the initial current / baseline may be relatively high. As the user moves the brush 10 from tooth to tooth, the force on the brush head 120 may periodically decrease. As a result, the measured current may also periodically decrease, and each time the current falls below a previous value, the baseline current is adjusted. Such adjustments to lower values ​​of the baseline current, as well as adjustments to higher values ​​of the baseline current, contribute to what is defined herein as the “dynamically adjusted baseline current”.

[0050] During the overpressure detection control loop, the microcontroller 170 first measures the instantaneous current draw of the motor 140 (at 310 in Figure 3) and compares the measured instantaneous current draw to the baseline current. If the instantaneous current is greater than or equal to the baseline current (high load condition of the motor), the microcontroller 170 adds an increment value to the baseline current (at 316). On the other hand, if the instantaneous current is less than the baseline current (low load condition of the motor), the microcontroller 170 subtracts a decrement value from the baseline current (at 316). By adding an increment value to the baseline current or subtracting a decrement value from the baseline current, the microcontroller 170 generates a dynamically adjusted baseline current that is used by the microcontroller 170 to detect the occurrence (or absence) of overpressure.

[0051] As explained earlier, since the low-load state is shorter than the high-load state, the decrease in baseline current must occur faster than the increase in baseline current; therefore, the decrement value can generally be set to be greater than the increment value. The decrement value can be at least 10, 20, and 30 times greater than the increment value. In one exemplary embodiment, the increment value may be 0.1 mA. In one exemplary embodiment, the decrement value may be 2 mA.

[0052] Next, the microcontroller (at 318 in Figure 3) adds the overpressure threshold to the dynamically adjusted baseline current to determine if the difference between the instantaneous current pull and the dynamically adjusted baseline current exceeds the overpressure threshold, and compares the instantaneous current pull to the sum of the dynamically adjusted baseline current and the overpressure threshold. If the instantaneous current pull is higher than the sum of the dynamically adjusted baseline current and the overpressure threshold (at 322, 324), the microcontroller 170 sets an overpressure detection flag indicating that the motor 140 is operating under overpressure, and in response to the detected overpressure, causes the toothbrush 10 to perform a corrective action. In other words, the pressure control system determines that the motor 140 is under overpressure by detecting that the instantaneous current exceeds the dynamically adjusted baseline current by at least the overpressure threshold. The corrective action can be selected from a group consisting of decelerating the motor, generating an optical signal, generating a tactile signal, generating an acoustic signal, and any combination thereof.

[0053] If the instantaneous current pull is less than the sum of the dynamically adjusted baseline current and the overvoltage threshold, no overvoltage is detected, and the microcontroller either (a) waits for the next control loop to begin without taking any additional action, or (b) cancels any corrective action in response to detecting that the overvoltage has been resolved (for example, by increasing the speed of motor 140 back to its initial speed).

[0054] The frequency at which the overpressure detection control loop is executed can be set to one overpressure detection control loop every 1 to 1000 milliseconds, more specifically, one overpressure detection control loop every 5 to 100 milliseconds, and even more specifically, one overpressure detection control loop every 0 milliseconds. The microcontroller 170 can be configured to implement a waiting period between two consecutive overpressure detection control loops (as shown in 326 in Figure 3) depending on the desired frequency and duration of the overpressure detection control loop.

[0055] The overpressure threshold includes a high-load (relatively high) threshold and a low-load (relatively low) threshold. The high-load threshold indicates a high-load condition of the motor 140, i.e., when the motor 140 is in an overpressure condition. Depending on the selected operating mode of the brush 10, the high-load threshold may be in the range of about 100mA to about 500mA, more specifically, in the range of about 150mA to about 300mA. In one exemplary embodiment, the high-load threshold may be about 200mA.

[0056] The low-load threshold indicates a low-load state of the motor, i.e., a state in which a low load is applied to the motor 140 (for example, when the motor 140 is no longer overloaded). The microcontroller 170 can be configured to determine whether the difference between the instantaneous current draw and the dynamically adjusted baseline current is less than the low-load threshold indicating a low-load state of the motor, in order to detect whether the overpressure has been resolved. The low-load threshold is less than the high-load threshold. The low-load threshold can be about 20% to about 90% of the high-load threshold. For example, the low-load threshold can be about 50mA to about 400mA. In one exemplary embodiment, the low-load threshold is about 50% lower than the high-load threshold.

[0057] In one embodiment, the microcontroller 170 configures the motor 140 to move at least one functional element (i.e., cleaning element 126) at a first (low-load) intensity when the difference between the instantaneous current draw and the dynamically adjusted baseline current is less than a low-load threshold. Then, if an overpressure is detected, the corrective action may include configuring the motor 140 to move at least one functional element 126 at a second (high-load) intensity different from the first intensity. The second intensity may be less than the first intensity. For example, the first intensity may include the normal speed of the motor 140, while the second intensity may include a reduced speed of the motor 140 compared to the normal speed. Naturally, a functional element 126 driven by a motor 140 at a reduced speed will move slower than one driven by a motor 140 at its normal / normal speed.

[0058] The pressure control system adapts the overpressure threshold over time by increasing or decreasing the baseline current value (i.e., by generating a dynamically adjusted baseline current) in each control loop, taking into account the changes in current draw introduced by the difference in brush head 120 and / or wear, and in a manner independent of the measurement of no-load current draw.

[0059] Furthermore, as previously explained, the pressure control system dynamically adjusts the baseline current during each overpressure detection control loop (312, 314, and 316 in Figure 3) before the comparison with the overpressure threshold is performed. Therefore, even when the electric toothbrush 10 is usable under no-load conditions for the motor 140, the dynamically adjusted baseline current value used for comparison is not the measured no-load current draw, but rather a modified version of the current that is increased by an increment value or decreased by a decrement value based on the result of the comparison between the instantaneous current and the baseline current.

[0060] In one embodiment, the microcontroller 170 determines the presence or absence of overpressure by performing two comparisons: a low-load comparison to detect the presence of an overpressure condition, and a high-load comparison to detect that the overpressure condition has been resolved. In the high-load comparison (322 in Figure 3), the microcontroller 170 compares the instantaneous current to the sum of the dynamically adjusted baseline current and the high-load threshold (indicating a high-load condition for the motor 140). If the instantaneous current exceeds the sum of the dynamically adjusted baseline current and the high-load threshold, the microcontroller 170 sets an overpressure indicator flag to indicate that the motor 140 is operating under overpressure and to reduce the speed of the motor 140.

[0061] In other words, the pressure control system determines that the motor 140 is overpressurized by detecting that the instantaneous current exceeds the dynamically adjusted baseline current by at least the high load threshold. Conversely, if the microcontroller 170 is less than the sum of the dynamically adjusted baseline current and the high load threshold, it takes no additional action and waits to start the next overpressure detection control loop.

[0062] In the low-load comparison (318 in Figure 3), the microcontroller 170 compares the instantaneous current to the sum of the dynamically adjusted baseline current and the low-load threshold. If the instantaneous current is less than the sum of the dynamically adjusted baseline current and the low-load threshold, the microcontroller 170 sets the overpressure indicator flag to "false" to indicate that the motor 140 is no longer operating under overpressure and to reset the motor 140's speed to its original speed. Conversely, if the instantaneous current is greater than or equal to the sum of the dynamically adjusted baseline current and the low-load threshold, the microcontroller 170 takes no further action and waits for the next overpressure detection control loop to begin.

[0063] The dimensions and values ​​disclosed herein should not be understood as strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified herein, each such dimension is intended to mean both the listed value and a functionally equivalent range encompassing that value. For example, a dimension disclosed as "40 mm" is intended to mean "approximately 40 mm" or "about 40 mm." Furthermore, approximate terms such as "approximately" and "about" may actually be used to refer to numerical values ​​that may actually embody values ​​that differ slightly from the exact values ​​listed. Thus, in the context of this disclosure, these terms may indicate the degree to which a quantitative value, measurement, or other relevant expression may vary slightly from the explicitly stated exact value without altering the fundamental functionality of the subject matter in question.

[0064] All disclosures of documents referenced herein, including any patents or patent applications that are cross-referenced or related, and any patent applications or patents for which this application claims priority or interest, are incorporated herein by reference in their entirety unless expressly excluded or otherwise limited. No citation of any document shall be deemed prior art to any invention disclosed or claimed herein, nor shall it be deemed to teach, suggest or disclose any such invention, either alone or in combination with any other reference(s). Furthermore, in the event of any conflict between any meaning or definition of a term in this document and any meaning or definition of the same term in any document incorporated herein by reference, the meaning or definition assigned to the term in this document shall prevail.

[0065] While specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. For example, the various drawings provided herein to illustrate exemplary embodiments should not be construed as limiting the invention as described in the claims herein. Accordingly, it is intended that all such changes and modifications within the scope of the invention be covered in the appended claims.

Claims

1. A method for controlling overpressure of an electric oral care device having a treatment head equipped with at least one functional element driven by a motor, wherein the method is - The step of detecting a stimulus and energizing the motor, - Steps to set the baseline current, - A step of repeatedly executing an overpressure detection control loop, ○ A step of measuring the instantaneous current draw of the motor, ○ A step of adding an increment value to the baseline current or subtracting a decrement value from the baseline current to generate a dynamically adjusted baseline current, ○ A step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold, thereby detecting the occurrence of overvoltage, A method comprising the step of repeatedly executing an overpressure detection control loop, which includes the step of performing a corrective action in response to the occurrence of the detected overpressure.

2. The step of setting the baseline current, - Measure the current draw of the motor and set the baseline current to the measured current draw, and / or The method according to claim 1, further comprising setting the baseline current to a predetermined value.

3. The step of adding an increment value to the baseline current or subtracting a decrement value from the baseline current is If the instantaneous current is greater than or equal to the baseline current, the increment value is added to the baseline current, or - The method according to claim 1 or 2, comprising subtracting the decrement value from the baseline current when the instantaneous current is less than the baseline current.

4. The method according to any one of claims 1 to 3, wherein the step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds the threshold includes adding the threshold to the dynamically adjusted baseline current.

5. The method according to any one of claims 1 to 4, wherein the step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds the threshold includes comparing the instantaneous current draw with the sum of the dynamically adjusted baseline current and the threshold.

6. The method according to any one of claims 1 to 5, further comprising the step of detecting whether the overpressure has been resolved.

7. The method according to any one of claims 1 to 6, wherein in the step of adding an increment value to the baseline current or subtracting a decrement value from the baseline current, the decrement value is greater than the increment value.

8. The method according to claim 7, wherein the decrement value is at least 10 times greater than the increment value, specifically, the decrement value is at least 20 times greater than the increment value.

9. The method according to any one of claims 1 to 8, wherein the method includes a stabilization step of energizing the motor in response to the detection of the stimulus, during which the measurement of the current draw and setting the baseline current is delayed, specifically the stabilization step lasting about 500 milliseconds to about 5000 milliseconds, and more specifically, the stabilization step lasting about 2000 milliseconds.

10. The method according to any one of claims 1 to 9, wherein the overpressure detection control loop is executed repeatedly once every 1 to 500 milliseconds, more specifically, the overpressure detection control loop is executed repeatedly once every 5 to 20 milliseconds, and more specifically, the overpressure detection control loop is executed repeatedly once every 10 milliseconds.

11. The method according to any one of claims 1 to 10, wherein the step of performing a corrective action is selected from the group consisting of slowing down the motor, generating an optical signal, generating a tactile signal, generating an acoustic signal, and any combination thereof, and specifically, in response to detecting that the overpressure has been resolved, the speed of the motor is increased again to its initial speed.

12. The method according to any one of claims 1 to 11, wherein the step of determining whether the difference between the instantaneous current draw and the dynamically adjusted baseline current exceeds a threshold, the threshold includes a high-load threshold indicating a high-load state of the motor and a low-load threshold indicating a low-load state of the motor.

13. The method according to claim 11 or 12, comprising the step of detecting whether the occurrence of the overpressure has been resolved, the step of determining that the difference between the instantaneous current draw and the dynamically adjusted baseline current is less than the low load threshold, more specifically, the step of configuring the motor to move the at least one functional element at a first intensity in response to determining that the difference between the instantaneous current draw and the dynamically adjusted baseline current is less than the low load threshold, and more specifically, the corrective action comprising configuring the motor to move the at least one functional element at a second intensity different from the first intensity.

14. The method according to claim 12 or 13, wherein the high load threshold is approximately 100 mA to approximately 500 mA.

15. The method according to any one of claims 12 to 14, wherein the low load threshold is approximately 20% to approximately 90% of the high load threshold.

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