Patent Description:
Due to the advantages of usage flexibility and convenience, an electric screwdriver is very popular on the market and widely used in the industry, household, and other occasions where screws need to be assembled and disassembled. However, a switch assembly is generally disposed in the current electric screwdriver on the market, and a user can drive an output shaft to rotate by operating the switch assembly; and when operating the electric screwdriver for long time nailing, the user needs to keep operating the switch assembly, which is not convenient for the user to operate, reducing the working efficiency.

<CIT> discloses a power tool according to the preamble of claim <NUM> that includes an output shaft configured to rotate about a longitudinal axis, a motor drivably connected to the output shaft to impart rotary motions thereto, and a rotational motion sensor spatially separated from the output shaft and operable to determine the user-imparted rotational motion of the power tool with respect to the longitudinal axis.

<CIT> discloses a screwdriver that includes a sliding switch for activating reversing operation of the drive motor is arranged on a housing, wherein a first activating unit is provided for activating the drive motor as a result of axial contact of the tool holder against a workpiece which is to be machined, and a second activating unit is provided for activating the drive motor as a result of activation of the operating element.

<CIT> discloses a drywall screwing machine comprising a drive unit, a control and/or regulating unit for controlling and/or regulating the drive unit, an input unit for inputting at least one characteristic variable and a drive unit rotation sensor unit which has at least one rotation sensor element for outputting a pulse as a function of a rotation characteristic variable of the drive unit.

The present invention provides an electric screwdriver that is easy to operate and has low power consumption.

The present invention adopts the technical solutions described below. An electric screwdriver includes a housing; an electric motor at least partially disposed in the housing and including a motor shaft rotatable about a motor axis; and an output assembly configured to output power and including an output shaft movable forward and backward along a direction of a first axis. The electric screwdriver further includes a startup circuit configured to start the electric motor. The startup circuit includes a switch assembly controlling the on state of the startup circuit; and an activation assembly including a detection element connected to the electric motor electrically or through a signal, and an activation element configured to activate the detection element. The output shaft is capable of driving the detection element, and the detection element includes at least one activated state during movement. When the detection element is in one of the at least one activated state and the switch assembly is on, the electric motor starts. The output shaft is capable of driving the detection element to rotate about a first axis of rotation, and the detection element is capable of being activated by the activation element during rotation.

In some examples, the activation element is fixedly disposed in the housing.

In some examples, the switch assembly includes a switch configured to control the on state of at least one of the detection element and the activation element.

In some examples, the activation element is disposed on a moving path of the detection element.

In some examples, the output shaft includes an input end and an output end disposed opposite to each other along the first axis, where the input end is disposed away from the electric motor relative to the output end; and when the input end is subjected to a force to move along the first axis in a direction toward the motor shaft, the output end is capable of driving the detection element to rotate toward the activation element.

In some examples, the electric screwdriver further includes a gearbox fixedly disposed in the housing, where the output shaft is at least partially disposed in the gearbox; and in a direction perpendicular to the first axis, the activation element is located above the output shaft and fixedly disposed on the gearbox.

In some examples, the activation assembly further includes a biasing member capable of providing a biasing force that keeps the detection element at an initial position when the detection element is not driven by an external force.

In some examples, the activation assembly further includes a rotary member to which the detection element is mounted, where the output end drives the rotary member to overcome the biasing force so that the detection element approaches the activation element.

In some examples, the activation element is a permanent magnet.

In some examples, the detection element is a Hall sensor.

An electric screwdriver not covered by the claims includes a housing; an electric motor at least partially disposed in the housing and including a motor shaft rotatable about a motor axis; and an output assembly configured to output power and including an output shaft movable forward and backward along a direction of a first axis. The electric screwdriver further includes a startup circuit configured to start the electric motor. The startup circuit includes a switch assembly controlling the on state of the startup circuit; and an activation assembly including at least one activated state. When the activation assembly is in one of the at least one activated state and the switch assembly is on, the electric motor starts; and in a direction perpendicular to the first axis, the activation assembly is located above the output shaft.

In some examples not covered by the claims, the activation assembly includes a detection element electrically connected to the electric motor or connected to the electric motor through a signal and an activation element configured to activate the detection element; and the output shaft is capable of driving the detection element, and the detection element includes at least one activated state during movement; where when the detection element is in one of the at least one activated state and the switch assembly is on, the electric motor starts.

In some examples not covered by the claims, the output shaft is capable of driving the detection element to rotate about a first axis of rotation, and the detection element is capable of being activated by the activation element during rotation.

In some examples, during movement, the detection element includes the at least one activated state in which the detection element is activated by the activation element to generate an activation signal and a sleep state in which the detection element is not activated by the activation element.

In some examples, when the detection element is in the sleep state, the distance between the detection element and the activation element is greater than or equal to <NUM> along the direction of the first axis.

An electric screwdriver not covered by the claims includes a housing; an electric motor at least partially disposed in the housing and including a motor shaft rotatable about a motor axis; and an output assembly configured to output power and including an output shaft movable forward and backward along a direction of a first axis. The electric screwdriver further includes a startup circuit configured to start the electric motor. The startup circuit includes a switch assembly controlling the on state of the startup circuit; and an activation assembly including a detection element electrically connected to the electric motor or connected to the electric motor through a signal and an activation element configured to activate the detection element. The detection element is drivable by the output shaft. During movement, the detection element includes an activated state in which the detection element is activated by the activation element to generate an activation signal and a sleep state in which the detection element is not activated by the activation element. When the activation assembly is in the activated state and the switch assembly is on, the electric motor starts; and when the detection element is in the sleep state, the distance between the detection element and the activation element is greater than or equal to <NUM> along the direction of the first axis.

An electric screwdriver <NUM> shown in <FIG> and <FIG> can be used to drive a fastener such as a screw into concrete or wood.

As shown in <FIG> and <FIG>, the electric screwdriver <NUM> includes a housing <NUM>, an electric motor <NUM>, a transmission assembly <NUM>, an output assembly <NUM>, a switch assembly <NUM>, an activation assembly <NUM>, and an energy source. The output assembly <NUM> includes an output shaft <NUM>, and the output shaft <NUM> can rotate about a first axis <NUM> to output power. The output shaft <NUM> can move along the first axis <NUM> when a force is applied, and the output shaft <NUM> can be restored to an original position when the external force is withdrawn. For the electric screwdriver, the electric screwdriver <NUM> may further include a functional element (not shown in the figure) connected to the output shaft <NUM> to drive the fastener such as the screw into the cement or wood. The functional element may be a bit.

To facilitate the description of the technical solutions of the present invention, up, down, front, rear, left, and right as shown in <FIG> are further defined.

The housing <NUM> includes an accommodation portion <NUM> and a handle portion <NUM>. The accommodation portion <NUM> is formed with an accommodation chamber <NUM>. The electric motor <NUM>, the transmission assembly <NUM>, and the activation assembly <NUM> are all disposed in the accommodation chamber <NUM>. The handle portion <NUM> is used for a user to hold. The handle portion <NUM> is connected to the accommodation portion <NUM>, and the handle portion <NUM> extends obliquely downward from the accommodation portion <NUM>.

The electric motor <NUM> is disposed in the accommodation chamber <NUM> formed by the accommodation portion <NUM>. The electric motor <NUM> includes a motor shaft <NUM> for outputting power. The motor shaft <NUM> can rotate about a motor axis <NUM> relative to the housing <NUM>. The motor axis <NUM> about which the motor shaft <NUM> rotates is basically parallel to the first axis <NUM> about which the output shaft <NUM> rotates. In this example, the motor axis <NUM> about which the motor shaft <NUM> rotates is parallel to and does not coincide with the first axis <NUM> about which the output shaft <NUM> rotates, and it is also to be understood that the output shaft <NUM> is disposed substantially on the upper side of the electric motor <NUM>.

The transmission assembly <NUM> is used for transmitting power outputted by the motor shaft <NUM> to the output shaft <NUM>. The transmission assembly <NUM> includes a first transmission member <NUM> and a second transmission member <NUM>, where the first transmission member <NUM> is fixedly connected to or integrally formed with the motor shaft <NUM>, the second transmission member <NUM> rotates synchronously with the output shaft <NUM>, and the first transmission member <NUM> is always engaged with the second transmission member <NUM>. The second transmission member <NUM> is always at least partially in contact with the output shaft <NUM> during the movement along the first axis <NUM> when a force is applied. The second transmission member <NUM> is formed with a sliding groove for the reciprocating movement of the output shaft <NUM>. The output shaft <NUM> is fixedly connected to or integrally formed with an engagement portion. The engagement portion always mates with the sliding groove, thereby ensuring the synchronous rotation of the second transmission member <NUM> and the output shaft <NUM>.

The output assembly <NUM> includes the output shaft <NUM>, where the output shaft <NUM> can move along the direction of the first axis <NUM> when a force is applied. In this example, the output shaft <NUM> includes an input end <NUM> and an output end <NUM> disposed opposite to each other along the direction of the first axis <NUM>, where the input end <NUM> is disposed away from the electric motor <NUM> relative to the output end <NUM>, and the functional element is mounted at the input end <NUM> of the output shaft <NUM>. The engagement portion is disposed near the output end <NUM> relative to the input end <NUM>.

The energy source is used for providing a source of energy to the electric screwdriver <NUM>. The energy source may be an alternating current or a direct current. In this example, the energy source is the direct current, that is, the energy source may be a battery pack. The battery pack may be inserted into the housing <NUM>, or the battery pack may be separated from the housing <NUM>, that is, the battery pack is not directly mounted on the surface of the housing <NUM>. As long as a power source can be supplied, a specific mounting manner is not limited herein.

Referring to <FIG>, the switch assembly <NUM>, the activation assembly <NUM>, and the electric motor <NUM> are defined herein as a startup circuit for ease of description of this solution. The startup circuit is used for controlling the stopping and operation of the electric motor <NUM>.

The startup circuit includes the switch assembly <NUM> and the activation assembly <NUM>, that is to say, the signals between the activation assembly <NUM> and the activation assembly <NUM> are connected in series. The switch assembly <NUM> is used for controlling the on state of the startup circuit and is at least partially disposed in the handle portion <NUM>. In this manner, it is convenient for the user to operate the switch assembly <NUM> when the user holds the handle portion <NUM>. The switch assembly <NUM> includes a trigger <NUM> for the user to operate and a switch <NUM> drivable by the trigger <NUM>, where the switch <NUM> is coupled to the electric motor <NUM>. It is to be noted that the coupling connection in the present application includes a signal connection, an electrical connection, and a mechanical connection. The trigger <NUM> is movable relative to the housing <NUM>, and the trigger <NUM> can drive the switch <NUM> to change the state during movement, that is, it is to be understood that the trigger <NUM> includes an open state and a closed state during movement. When the trigger <NUM> is in the open state, the startup circuit is turned on, that is to say, at this time, the trigger <NUM> allows the motor shaft <NUM> to provide power to the output shaft <NUM>. When the trigger <NUM> is in the closed state, the startup circuit is turned off, that is to say, the trigger <NUM> prohibits the motor shaft <NUM> from providing power to the output shaft <NUM>.

The activation assembly <NUM> is disposed in the accommodation chamber <NUM> and includes a detection element <NUM> and an activation element <NUM>. The detection element <NUM> is electrically connected to the electric motor <NUM> or connected to the electric motor <NUM> through a signal, and the activation element <NUM> is used for activating the detection element <NUM>. The detection element <NUM> is driven by the output shaft <NUM> to move, and the activation element <NUM> is disposed on a moving path of the detection element <NUM>. During movement, the detection element <NUM> includes an activated state in which the detection element <NUM> is activated by the activation element <NUM> to generate an activation signal and a sleep state in which the detection element <NUM> is not activated by the activation element <NUM>.

In this example, when the detection element <NUM> is in the activated state and the switch assembly <NUM> is on, the electric motor <NUM> starts. That is, the electric motor <NUM> cannot start when either the detection element <NUM> is in the sleep state or the trigger <NUM> is in the closed state. In this manner, the noise of the electric motor <NUM> when the electric screwdriver <NUM> is not loaded can be reduced, thereby extending the working duration of the battery pack. It is to be noted here that the output shaft <NUM> drives the detection element <NUM> to move, which may be understood that the output shaft <NUM> directly drives the detection element <NUM> to translate, rotate, slide, or the like, or the output shaft <NUM> indirectly drives the detection element <NUM> to translate, rotate, slide, or the like. In this example, the output shaft <NUM> drives the detection element <NUM> to rotate about a first axis of rotation <NUM>, and when rotating, the detection element <NUM> can be activated by the activation element <NUM> so that the detection element <NUM> is in the activated state.

As an example, while the switch <NUM> sends a signal to the electric motor <NUM>, the switch <NUM> can also control the on state of the detection element <NUM>. That is, it is to be understood that when the user operates the trigger <NUM> and drives the switch <NUM> to the open state, the switch <NUM> enables the detection element <NUM> to be powered on through an electrical connection or a signal connection, and in the same time unit, the user drives the shaft to move the detection element <NUM> so that the activation element <NUM> activates the detection element <NUM> and the electric motor <NUM> starts. That is, the user cannot start the electric motor <NUM> by either driving only the trigger <NUM> or driving only the output shaft <NUM> in the same time unit. That is to say, in this example, only after the trigger <NUM> is driven, the detection element <NUM> can be powered on and activated by the activation element <NUM>. For example, the detection element <NUM> may be a Hall sensor and the activation element <NUM> may be a permanent magnet. Of course, the detection element <NUM> may also be other sensors, which is not limited, as long as the preceding conditions can be satisfied.

As another example, while the switch <NUM> sends a signal to the electric motor <NUM>, the switch <NUM> can also enable the activation element <NUM> to be powered on so that the activation element <NUM> is turned on, and the detection element <NUM> is powered in other manners. That is, it is to be understood that when the user operates the trigger <NUM> and drives the switch <NUM> to the open state, the switch <NUM> enables the detection element <NUM> to be powered on through an electrical connection or a signal connection, and in the same time unit, the user drives the shaft to move the detection element <NUM> so that the activation element <NUM> activates the detection element <NUM> and the electric motor <NUM> starts. That is, it is to be understood that only after the trigger <NUM> is driven, the activation element <NUM> can be powered on and can activate the detection element <NUM>. For example, the detection element <NUM> may be a light sensor and the activation element <NUM> may be a light-emitting element. Of course, the detection element <NUM> may be the Hall sensor and the activation element <NUM> may be an electromagnet. Of course, the detection element <NUM> may also be other types of sensors, which is not limited, as long as the preceding conditions can be satisfied.

As some other examples, while the switch <NUM> sends a signal to the electric motor <NUM>, the switch <NUM> can also enable the activation element <NUM> and the detection element <NUM> to be powered on so that the activation element <NUM> and the detection element <NUM> are turned on. That is, it is to be understood that when the user operates the trigger <NUM> and drives the switch <NUM> to the open state, the switch <NUM> enables the detection element <NUM> and the activation element <NUM> to be powered on through an electrical connection or a signal connection, and in the same time unit, the user drives the shaft to move the detection element <NUM> so that the activation element <NUM> activates the detection element <NUM> and the electric motor <NUM> starts. That is, it is to be understood that only after the trigger <NUM> is driven, the activation element <NUM> and the detection element <NUM> can be powered on, and the activation element <NUM> can activate the detection element <NUM>. For example, the detection element <NUM> may be the light sensor and the activation element <NUM> may be the light-emitting element. Of course, the detection element <NUM> may also be other types of sensors, which is not limited, as long as the preceding conditions can be satisfied.

As other examples, the activation assembly <NUM> may also be powered in other manners, that is, the activation assembly <NUM> is not affected by the switch <NUM>, and the switch <NUM> is allowed to enable only the electric motor <NUM> to be powered. However, it is still satisfied that when the trigger <NUM> is in the open state and the detection element <NUM> is in the activated state, the electric motor <NUM> is started. It is to be understood that the open state of the trigger <NUM> does not refer to a single position, but may correspond to multiple positions, as long as the switch <NUM> can send the signal to the electric motor <NUM> when the trigger <NUM> is at a certain position. The same is true for the closed state of the trigger <NUM>.

The activated state of the detection element <NUM> does not refer to a single position, but may correspond to multiple positions, as long as the detection element <NUM> can send the signal to the electric motor <NUM> when the detection element <NUM> is at a certain position. The same is true for the sleep state of the detection element <NUM>. Meanwhile, it is to be noted that, considering the case where the switch <NUM> enables the detection element <NUM> or/and the activation element <NUM> to be powered on and the detection element <NUM> is not in the activated state no matter which position the detection element <NUM> is forced to move, to facilitate a clear description of the content of this solution, the position at which the detection element <NUM> not driven by an external force is located is defined as an initial position (as shown in <FIG>), and when the detection element <NUM> is at the initial position, the detection element <NUM> is in the sleep state.

As shown in <FIG>, the electric screwdriver <NUM> further includes a gearbox <NUM> at least partially disposed in the accommodation chamber <NUM> and an elastic member <NUM> disposed in the gearbox <NUM>, where the gearbox <NUM> is fixedly connected to the housing <NUM>. In this example, the output shaft <NUM> can penetrate through the gearbox <NUM> and drive the detection element <NUM> to rotate. For example, the input end <NUM> is subjected to a force to move along the direction of the first axis <NUM> so that when moving backward along the direction of the first axis <NUM>, the output end <NUM> can drive the detection element <NUM> to rotate about the first axis of rotation <NUM>. The elastic member <NUM> is used for restoring the elastic member <NUM> to an original position, the elastic member <NUM> is sleeved on the output shaft <NUM>, an end of the elastic member <NUM> abuts against a protrusion formed by the output shaft <NUM>, and the other end of the elastic member <NUM> abuts against the second transmission member <NUM>. The output shaft <NUM> is subjected to a force to move backward so that the elastic member <NUM> has elastic deformation and generates a deformation force. When the external force is withdrawn, the output shaft <NUM> is restored to the original position due to the deformation force. In fact, it is easily found that the original position of the output shaft <NUM> is often not fixed due to installation or operation, which we do not care about, as long as the position at which the output shaft <NUM> not affected by any external force is located may be understood as the original position.

When the detection element <NUM> is in the sleep state, the distance D between the detection element <NUM> and the activation element <NUM> is greater than or equal to <NUM> along the direction of the first axis <NUM>. In the present application, the detection element <NUM> is driven by the output shaft <NUM> to move to the activation element <NUM>, that is to say, a certain distance exists between the detection element <NUM> and the activation element <NUM>. The detection element <NUM> is configured to rotate about the first axis of rotation <NUM>, the detection element <NUM> does not need to move a long distance to be activated by the activation element <NUM>, and too much space due to the moving path of the detection element <NUM> does not need to be provided in the housing <NUM> so that the structure is optimized, too large a length of the electric screwdriver <NUM> along the direction of the first axis <NUM> can be avoided, and the miniaturization of the electric screwdriver <NUM> is achieved.

In the direction perpendicular to the first axis <NUM>, the activation assembly <NUM> is disposed on the upper side of the motor shaft <NUM>, where the activation element <NUM> is disposed on the upper side of the first axis <NUM>, thereby facilitating the setting of other parts. Further, the first axis of rotation <NUM> is basically perpendicular to the first axis <NUM>.

The activation element <NUM> is fixedly disposed in the housing <NUM>, where the activation element <NUM> may be located on the moving path of the detection element <NUM> or in the vicinity of the moving path of the detection element <NUM>, as long as when the detection element <NUM> moves to a certain position, the activation element <NUM> can activate the detection element <NUM> so that the activation element <NUM> transmits the activation signal to the electric motor <NUM>. That is to say, the activation method between the detection element <NUM> and the activation element <NUM> does not necessarily mean that the detection element <NUM> is in contact with the activation element <NUM>, but may also mean that a distance exists between the detection element <NUM> and the activation element <NUM>. In this example, the activation element <NUM> is fixedly connected to the gearbox <NUM>. For example, a groove is disposed on a side of the gearbox <NUM> adjacent to the electric motor <NUM>, and the detection assembly <NUM> is disposed in the groove. On the premise that the trigger <NUM> is always in the open state, the output shaft <NUM> drives the detection element <NUM> to approach the gearbox <NUM> so that when the detection element <NUM> rotates from the sleep state to the activated state, the activation element <NUM> is at least partially in contact with the detection element <NUM>.

Claim 1:
An electric screwdriver (<NUM>), comprising:
a housing (<NUM>);
an electric motor (<NUM>) at least partially disposed in the housing and comprising a motor shaft (<NUM>) rotatable about a motor axis (<NUM>); and
an output assembly (<NUM>) configured to output power and comprising an output shaft (<NUM>) movable forward and backward along a direction of a first axis (<NUM>);
wherein the electric screwdriver further comprises:
a startup circuit configured to start the electric motor;
wherein the startup circuit comprises:
a switch assembly (<NUM>) controlling an on state of the startup circuit; and
an activation assembly (<NUM>) comprising a detection element (<NUM>) connected to the electric motor electrically or through a signal, and an activation element (<NUM>) configured to activate the detection element;
wherein the output shaft is capable of driving the detection element, and the detection element comprises at least one activated state during movement; and
when the detection element is in one of the at least one activated state and the switch assembly is on, the electric motor starts,
characterized in that,
the output shaft is capable of driving the detection element to rotate about a first axis of rotation (<NUM>), and the detection element is capable of being activated by the activation element during rotation.