Patent ID: 12226883

DETAILED DESCRIPTION

Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals or terminal portions of reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics.

It should be noted herein that for clarity of description, spatially relative terms such as “top,” “bottom,” “upper,” “lower,” “on,” “above,” “over,” “downwardly,” “upwardly” and the like may be used throughout the disclosure while making reference to the features as illustrated in the drawings. The features may be oriented differently (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein may be interpreted accordingly.

Referring toFIGS.1,2and3, a first embodiment of an electrically-driven tool according to this disclosure is a pneumatic electric nail gun that includes a nail gun body device1, an actuator device2, a kinetic device3and an electrically-controlled device4.

The nail gun body device1includes a nail gun body11, a nail gun seat12that is mounted to the nail gun body11and that is adapted to load a nail (not shown), a trigger13that is mounted to the nail gun body11and that is configured to be pulled to move, a safety unit14that is partly disposed between the nail gun seat12and the actuator device2and that is operable to move along an X-axis direction, and a nail container15that is connected to the nail gun seat12and that is adapted to accommodate a plurality of nails (not shown). The safety unit14is adapted to move when a tip of the nail gun is firmly pressed against an object (not shown).

The actuator device2is configured to output kinetic energy during a predetermined stroke (e.g., a nailing stroke), and includes a gas storage cylinder21that is mounted to the nail gun body11and that is configured for storing gas under a predetermined air pressure (namely, pressurized gas), a striking cylinder22that is connected to the nail gun seat12and that is configured for receiving the pressurized gas from the gas storage cylinder21, a piston assembly23that is movably disposed in the striking cylinder22, and a lifting gear24that is rotatably mounted to the nail gun seat12.

The piston assembly23includes a piston231that is in airtight contact with an inner surface of the striking cylinder22, a lifting rod232that is connected to the piston231and that is detachably engaged with the lifting gear24, and a driving pin233that is connected to the piston231and that is disposed in the nail gun seat12. The driving pin233is adapted to strike a nail.

In this embodiment, the lifting gear24is configured to have a teeth-missing portion, so that the lifting gear24will detach from the lifting rod23in a short period of time during a revolution of the lifting gear24. When the lifting gear24detaches from the lifting rod23, the piston assembly23will be driven by the predetermined air pressure of the gas that enters the striking cylinder22to move from a preparation position (e.g., a position where the piston assembly23that is drawn by solid lines is located inFIG.2) to a completion position (e.g., a position where the piston231that is drawn by chain lines is located inFIG.2) along the X-axis direction. The piston231of the piston assembly23is distal from the lifting gear24when the piston assembly23is at the preparation position, and is adjacent to the lifting gear24when the piston assembly23is at the completion position.

Since the structure of the pneumatic electric nail gun and the actions of nail-striking and restoring the piston assembly23back to the preparation position are known in the art, the descriptions above should be sufficient to enable persons skilled in the art to derive and expand more details thereon, and thus more relevant explanations will be omitted herein for the sake of brevity.

The kinetic device3is mounted to the nail gun body device1, and is configured to generate mechanical energy for the actuator device2to output as the kinetic energy during the predetermined stroke. The kinetic device3includes a motor31to be activated to convert electric energy into the mechanical energy during the predetermined stroke, and a movable component32disposed to perform a pre-arranged movement during the predetermined stroke.

The motor31rotates the lifting gear24when activated. In this embodiment, the movable component32may be a magnetic component. In one example, the movable component32is a magnet that is mounted to the lifting gear24, so the movable component32can perform the pre-arranged movement with the rotation of the lifting gear24(e.g., performing a cycle of revolution around an axle of the lifting gear24with a cycle of rotation of the lifting gear24).

The electrically-controlled device4is mounted to the nail gun body11, and includes a battery40, a power circuit41, a driving module42, a trigger switch43, a safety switch44, a detector switch45, an alarm component46, a battery voltage sensing circuit47, a motor current sensing circuit48and a controller49.

The battery40is configured to supply electric power required by the electrically-driven tool.

The power circuit41is electrically connected to the battery40, the controller49and the driving module42, and is configured to provide the electric power received from the battery40(e.g., at a direct-current (DC) voltage of 18 volts) after voltage stabilization and voltage regulation. The power circuit41may include, for example, two low-dropout regulators (LDOs) configured to provide two different voltages that are respectively provided to the controller49and the driving module42.

The driving module42includes a driving circuit421and a switching circuit422. The driving circuit421receives a pulse width modulation (PWM) signal outputted by the controller49, and controls the switching circuit422to drive the motor31to rotate at a target rotational speed based on a duty ratio of the PWM signal. In some embodiments, the switching circuit422may be realized using a metal-oxide-semiconductor field-effect transistor (MOSFET).

The trigger switch43is disposed to be triggered by the trigger13when the trigger13is being pulled, so as to output a trigger signal S1.

The safety switch44is disposed to be triggered by the safety unit14when the safety unit14is being moved by pressing, so as to output a safety signal S2.

In this embodiment, the detector switch45is a magnetic sensor, such as a Hall sensor, and is installed at a position that corresponds to a specific location where the movable component32is located when the lifting gear24is in a standby position before starting the predetermined stroke. When the movable component32is located at the specific location, the detector switch45will sense a magnetic field created by the movable component32, and thus generate a detection signal S3.

The alarm component46is mounted to the nail gun body11, and is configured to generate an alarm message. The alarm component46can be a light emitting component (e.g., a light emitting diode), a buzzer, a display, other suitable components, or any combination thereof, and the alarm message may be presented in a form of light, sound, text, or any combination thereof.

The battery voltage sensing circuit47is connected between the battery40and the controller49for sensing a voltage of the battery40, and for the controller49to adjust the duty ratio of the PWM signal that is outputted to the driving circuit421based on the voltage of the battery40, thereby maintaining operation of the motor31at the target rotational speed.

The motor current sensing circuit48is configured to sense a current of the motor31for the controller49to monitor the current of the motor31. In one example, overcurrent protection may be performed by the controller49controlling the driving circuit421to terminate operation of the motor31when the current of the motor31is excessively large.

The controller49is configured to receive the trigger signal S1, the safety signal S2and the detection signal S3, to control the motor31based on the trigger signal S1, the safety signal S2and the detection signal S3, and to output a battery abnormality signal S4upon determining that the battery40is in an abnormal state, so as to control the alarm component46to generate the alarm message.

For ease of explanation hereinafter, all directions to be used is based upon the face ofFIG.2. For example, a direction pointing from the piston231toward the nail gun seat12is to be referred to as a downward direction, and a direction pointing from the piston231away from the nail gun seat12is to be referred to as an upward direction.

Normally (namely, when the pneumatic electric nail gun is not performing the predetermined stroke), the piston231is disposed in an upper portion of the striking cylinder22and distal from the nail gun seat12, namely, the piston assembly23is at the preparation position, and the gas storage cylinder21is sealed and stores the pressurized gas therein.

When the battery40supplies the required electric power through the power circuit41and the lifting gear24is correctly at the standby position, the detector switch45would sense presence of the movable component32and output the detection signal S3. If a user intends to operate the pneumatic electric nail gun to strike a nail into an object (not shown), he/she may firmly press the safety unit14against the object to make the safety unit14move upwardly along the X-axis direction, so as to trigger the safety switch44to output the safety signal S2. While maintaining the safety unit14in this state, the user can pull the trigger13, such that the trigger13moves to trigger the trigger switch43to output the trigger signal S1. Upon receipt of the trigger signal S1under this circumstance (namely, the controller49receives the detection signal S3, the safety signal S2and the trigger signal S1all together at that moment), the controller49activates the motor31to perform the predetermined stroke of the actuator device2. During the predetermined stroke, the motor31rotates the lifting gear24in a counterclockwise direction. When the lifting gear24rotates to be disengaged from the lifting rod232for a brief moment, the lifting rod232is no longer resisted by the lifting gear24and the piston231is thus driven by the air pressure of the pressurized gas to move downwardly to the completion position. The movement of the piston231drives the driving pin233to slide in the nail gun seat12along the X-axis direction, so as to output the kinetic energy and strike the nail.

After completion of the nail striking, the lifting gear24is still driven by the motor31to continuously rotate in the counterclockwise direction to be engaged with the lifting rod232again, and to make the lifting rod232move upwardly through the engagement, so as to push the piston231and the driving pin233back to the preparation position. The upward movement of the piston231pushes the gas in the striking cylinder22to enter the gas storage cylinder21, and the gas is thus pressurized and stored in the gas storage cylinder21.

Briefly speaking, during a complete cycle of rotation of the lifting gear24, the piston assembly23is driven by the air pressure to move downwardly to perform nail striking, and then the motor31is driven by the electric power to move the piston assembly23upwardly to have the gas pressurized at the predetermined air pressure, so the pneumatic electric nail gun returns back to the standby state.

A method for detecting battery decline according to this disclosure is described hereinafter using the first embodiment of the electrically-driven tool as an example, and is implemented by the controller49. The method includes three primary steps (A), (B) and (C).

In step (A), a dataset of power provision time is pre-stored in the controller49. The dataset of energy provision time is related to a period of time required by the battery40to provide a predetermined amount of electric energy, and includes at least one data piece of energy provision time that signifies a predetermined time length T0presumed to be required by the battery40to provide the predetermined amount of electric energy. In this embodiment, the dataset of energy provision time includes a plurality of data pieces of energy provision time, each of which corresponds to a respective one of different battery specifications of a battery, wherein each battery specification relates to a specific type or connection method of multiple battery cells of the battery. The data piece of energy provision time that signifies the predetermined time length T0corresponds to the battery specification of the battery40of the electrically-driven tool.

In this embodiment, the controller49detects the battery specification of the battery40, and acquires one of the data pieces of energy provision time that corresponds to the battery40based on the battery specification thus detected. The battery specification determines the discharging capability of the battery40, and is related to the type (e.g., 18650-type, 21700-type, etc.) or connection method (e.g., 5S1P configuration, 5S2P configuration, etc., where “S” stands for series connection, and “P” stands for parallel connection) of multiple battery cells of the battery40.

In electrically-driven tools, different types and/or different connection methods of battery cells of batteries may lead to different electric resistances, so the controller49may detect an electric resistance of the battery40, and use a pre-stored lookup table that records relationships between electric resistances and battery specifications to obtain the battery specification of the battery40. In one example, batteries of different battery specifications may be configured to include different identification resistors of different resistances, and the electrically-driven tool may be configured to include a voltage divider resistor, such that the identification resistor and the voltage divider resistor are connected in series when the battery40is installed in the electrically-driven tool, and the controller49can identify the battery specification of the battery40based on a division voltage resulting from the voltage divider resistor.

In step (B), the controller49controls the driving module42to provide the predetermined amount of electric energy to the kinetic device3to have the kinetic device3perform the predetermined stroke with a predetermined load, and times a stroke time period T taken by the predetermined stroke.

In this embodiment, the predetermined stroke corresponds to a pre-arranged movement of the movable component32(e.g., the movable component32revolves around an axle of the lifting gear24with the rotation of the lifting gear24in the embodiment, and the pre-arranged movement refers to a complete cycle of the revolution of the movable component32).

In step (C), the controller49determines whether the stroke time period T is greater than the predetermined time length T0, and outputs the battery abnormality signal S4upon determining that the stroke time period T is greater than the predetermined time length T0.

The determination is made based on an equation of
W=P×t=U×I×t(1)
where W represents electric energy consumed by the electrically-driven tool in a single predetermined stroke, presented in a unit of joules (J); P represents power, which is related to work done in a single predetermined stroke; t represents a period of time taken by a single predetermined stroke, presented in a unit of seconds; U represents voltage provided by the battery presented in a unit of volts (V); and I represents current outputted by the battery40, presented in a unit of amperes (A).

It can be derived from equation (1) that, when the kinetic device3performs the predetermined stroke with a predetermined load, since the predetermined stroke and the predetermined load are known factors that have fixed values, the electric energy consumed by the electrically-driven tool would be a fixed value that is known. Therefore, by measuring the voltage of the battery40(i.e., the parameter “U” in equation (1)) and the stroke time period T (i.e., the parameter “t” in equation (1)), the current outputted by the battery40(i.e., the parameter “I” in equation (1)) can be acquired, and the controller49can thus determine whether the battery40is able to output the current normally. When the battery40has declined in terms of its discharging capability (i.e., the parameter “I” becomes smaller) because of prolonged use, time required to provide the predetermined amount of electric energy (i.e., the stroke time period T) would increase. Accordingly, the controller49can determine whether the capacity of the battery40has declined to an abnormal state by determining whether the stroke time period T is greater than the predetermined time length T0. For example, assuming that the battery40that operates normally is able output a current of 2.5 A at a low voltage of 16 V to provide the predetermined amount of electric energy in 0.4 seconds or less, the predetermined time length T0can be set as 0.4 seconds. When the stroke time period T measured by the controller49is greater than 0.4 seconds, the controller49may determine that the capacity of the battery40has declined to an abnormal state.

In detail, the method for detecting battery decline according to this disclosure may include steps S01to S09, as shown inFIG.4.

In step S01, the battery40supplies the electric power, and the electrically-driven tool enters a standby mode.

In step S02, the controller49determines whether the detection signal S3is received. The flow goes to step S03when the determination is affirmative, and goes back to step S01when otherwise, which means that the detector switch45is unable to detect the movable component32, and the lifting gear24may be at an abnormal position.

In step S03, the controller49determines whether the safety signal S2is received. The flow goes to step S04when the determination is affirmative, and goes back to step S01when otherwise, which means that the safety unit14is not pressed against an object (not shown) to be nailed.

In step S04, the controller49determines whether the trigger signal S1is received. The flow goes to step S05when the determination is affirmative, and goes back to step S01when otherwise, which means that the trigger13is not being pulled.

In step505, the controller49activates the motor31to perform the predetermined stroke with the predetermined load, and starts to time the stroke time period T. In other words, the controller49starts the predetermined stroke based on the trigger signal. The predetermined load is a known load that is predetermined. In the pneumatic electric nail gun, the motor31rotates to compress the gas, and the load results from the air pressure of the gas, which is a fixed value. The predetermined stroke is a fixed stroke that is predetermined. In the pneumatic electric nail gun, the motor31rotates for a fixed angle to drive rotation of the lifting gear24in a complete cycle during a single predetermined stroke, thereby making the movable component32perform the pre-arranged movement.

In step S06, the controller49determines whether the detection signal S3is received again. The flow goes to step S07when the determination is affirmative, and the controller49continuously repeats step S06and controls the motor31to maintain the operation when otherwise.

In step S07, the controller49terminates the operation of the motor31, and the flow ends. In other words, the controller49ends the predetermined stroke based on the detection signal.

In other words, the stroke time period T is a period of time during which the motor31is activated. According to the description concerning the procedure of the nail striking, it is known that, in a single predetermined stroke, the lifting gear24turns exactly one full circle (which corresponds to the fixed angle the motor31rotates for), and the piston assembly23is driven by the air pressure to complete the nail striking and is driven by the force from the rotation of the lifting gear24to complete the compression of the gas. Therefore, an initial position of the movable component32, which is magnetic in this embodiment, is set to correspond to the position of the detector switch45(i.e., the Hall sensor in this embodiment), so that when the detector switch45detects the movable component32again after the movable component32starts to revolve with the rotation of the lifting gear24, the movable component32has turned exactly one full circle, and the controller49will receive the detection signal S3again to terminate the operation of the motor31.

In step S08, the controller49determines whether the stroke time period T is greater than the predetermine time length T0. The flow goes to step S09when the determination is affirmative, and goes back to step S01when otherwise.

In step S09, the controller49outputs the battery abnormality signal S4to the alarm component46, and controls the alarm component46to generate the alarm message. Then, the flow goes back to step S01.

The alarm message is used to notify the user that the capability of the battery40in storing electric energy and discharging has seriously declined, and the battery40needs to be replaced.

It is noted that the electrically-driven tool according to this disclosure is not limited to the pneumatic electric nail gun as exemplified inFIGS.1and2. In a second embodiment, the electrically-driven tool can be a spring-loaded electric nail gun as exemplarily illustrated inFIG.5. The spring-loaded electric nail gun also includes a nail gun body device1, an actuator device2, a kinetic device3that includes a motor31, and an electrically-controlled device4. The second embodiment differs from the first embodiment in the following respects.

The actuator device2of the second embodiment includes a resilient component25(e.g., a spring), a nail-striking assembly26to be driven by the resilient component25for striking a nail, and a lifting gear assembly27to be rotated by the motor31and detachably engaged with the nail-striking assembly26.

The nail-striking assembly26is disposed at a side of the lifting gear assembly27, and includes a striker mechanism261that is movable in the X-axis direction, a connecting component262that is connected to and moves together with the striker mechanism261, and a movable component32that is connected to and moves together with the striker mechanism261.

The lifting gear assembly27has two protrusions271that are configured to drive movement of the movable component32and the connecting component262when the lifting gear assembly27rotates, so as to move the striker mechanism261from a preparation position to a top dead center (TDC) position to compress the resilient component25for storing elastic potential energy. During the movement of the striker mechanism261from the preparation position to the top dead center position, the movable component32continuously presses the detector switch45and the detection signal S3is thus continuously outputted. When the lifting gear assembly27releases the nail-striking assembly26, the nail-striking assembly26is driven by the elastic potential energy stored in the resilient component25to move from the top dead center position to a bottom dead center (BDC) position to generate the kinetic energy.

It is noted that, when the controller49receives the detection signal S3, the motor31may keep rotating for a predetermined period of time to move the nail-striking assembly26to the preparation position, which is between the top dead center position and the bottom dead center position.

Briefly speaking, during a single predetermined stroke, the lifting gear assembly27moves the nail-striking assembly26from the preparation position to the top dead center position, and then the nail-striking assembly26is driven by the elastic force from the resilient component25to complete the nail striking and driven by the force from the rotation of the lifting gear assembly27to complete the compression of the resilient component25that stores the elastic potential energy. The movement of the nail-striking assembly26during the predetermined stroke brings the movable component32into the pre-arranged movement.

In the spring-loaded electric nail gun, the load comes from the elastic force to be stored in the resilient component25when compressed by the motor31rotating to move the nail-striking assembly26, so the load has a predetermined fixed value which is known. In cooperation with the predetermined stroke that is known as well, the electric energy consumed by the spring-loaded electric nail gun would be a fixed value that is known. Therefore, the method of this disclosure can determine the capability of the battery40of the spring-loaded electric nail gun in storing the electric energy and discharging based on the stroke time period T.

It is noted that the structure for the spring-loaded electric nail gun to perform nail striking is not the focus of this disclosure, and reference thereof may be made to, for example, US Patent Publication Application No. 20210276171, Japanese Patent Publication No. 2007090473A, Japanese Patent Publication No. 2022068526, etc., so details of the structure for the spring-loaded electric nail gun to perform nail striking are omitted herein for the sake of brevity.

It is noted that the electrically-driven tool of this disclosure is not limited to the pneumatic electric nail gun as illustrated inFIGS.1and2or the spring-loaded electric nail gun as illustrated inFIG.5. In a third embodiment of this disclosure, the electrically-driven tool is a rebar tying machine as illustrated inFIG.6. The rebar tying machine includes a machine body device (not shown), an actuator device2, a kinetic device3that includes a motor31and a movable component32, and an electrically-controlled device4(as depicted inFIG.3). The third embodiment differs from the first embodiment in the following respects.

The actuator device2of the third embodiment includes two driving wheels28that are rotatable, and a transmission gear set29that is configured to be driven by the motor31to transmit the mechanical energy from the motor31to the driving wheels28that are configured to generate the kinetic energy to move a wire5. In this embodiment, the transmission gear set29includes an intermediate gear291that is disposed to bring the driving wheels28into rotation.

In the third embodiment, the movable component32is mounted to the intermediate gear291of the transmission gear set29.

During a single predetermined stroke, the intermediate gear291turns exactly one full circle (which corresponds to the fixed angle the motor31rotates for), and the driving wheels28are driven by the force from the rotation of the intermediate gear291to move the wire5.

In the rebar tying machine, the load comes from the weight of the wire5, so the load has a predetermined fixed value which is known. In cooperation of the predetermined stroke that is known as well, the electric energy consumed by the rebar tying machine would be a fixed value that is known. Therefore, the method of this disclosure can determine the capability of the battery40of the rebar tying machine in storing the electric energy and discharging based on the stroke time period T.

It is noted that the structure for the rebar tying machine to tie rebars is not the focus of this disclosure, and reference thereof may be made to, for example, European Patent Publication No. 1415917131, etc., so details of the structure for the rebar tying machine to tie rebars are omitted herein for the sake of brevity.

In summary, the method for detecting battery decline is adapted for use in an electrically-driven tool that has a fixed predetermined stroke. In a case where the load is known and thus the electric energy to be consumed in the predetermined stroke is known, the controller49that implements the method can determine the capability of the battery40in storing the electric energy and discharging based on the stroke time period T, thereby enabling the user to replace the battery40at the appropriate time.

In the description above, for the purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiment(s). It will be apparent, however, to one skilled in the art, that one or more other embodiments may be practiced without some of these specific details. It should also be appreciated that reference throughout this specification to “one embodiment,” “an embodiment,” an embodiment with an indication of an ordinal number and so forth means that a particular feature, structure, or characteristic may be included in the practice of the disclosure. It should be further appreciated that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects; such does not mean that every one of these features needs to be practiced with the presence of all the other features. In other words, in any described embodiment, when implementation of one or more features or specific details does not affect implementation of another one or more features or specific details, said one or more features may be singled out and practiced alone without said another one or more features or specific details. It should be further noted that one or more features or specific details from one embodiment may be practiced together with one or more features or specific details from another embodiment, where appropriate, in the practice of the disclosure.

While the disclosure has been described in connection with what is(are) considered the exemplary embodiment(s), it is understood that this disclosure is not limited to the disclosed embodiment(s) but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.