Patent Description:
Specifically, the present disclosure relates to an invention of the generic type as defined in the generic part of the independent claim attached.

Document <CIT> discloses a grass trimmer of the generic type as defined above. Specifically, this document discloses a trimmer head including a spool formed with a winding portion for winding a trimmer line and a head housing formed with an accommodating space for accommodating at least a portion of the spool. The trimmer head further includes an intermediate element for transmitting a torque between the spool and the head housing such that one of the spool and the head housing rotates with the other. The spool drives the intermediate element to rotate, and the intermediate element is slidably connected to the spool in a direction along a rotation axis or parallel to the rotation axis.

As a garden tool, a grass trimmer may generally be used for trimming lawns or trimming weeds around corners and shrubs.

The grass trimmer includes a grass trimmer head, and a grass trimmer rope is disposed on the grass trimmer head. When rotating at a high speed, the grass trimmer head can drive the grass trimmer rope to rotate together, and the grass trimmer rope rotating at a high speed trims grass. When the grass trimmer rope is too worn out to trim grass, a user needs to install a new grass trimmer rope on the grass trimmer head. The grass trimmer head generally includes a head housing and a spool disposed in the head housing, and the grass trimmer rope may be wound around the spool.

In the related art, the user generally needs to open the head housing, take out the spool, wind the grass trimmer rope around the spool, and then re-install the spool into the head housing. In this manner, the user winds the grass trimmer rope, which is time-consuming and labor-intensive, and the operation efficiency is low. Moreover, the user's hands need to touch the grass trimmer head, which is easy to soil the user's hands.

Further grass trimmers are e.g. known from <CIT> and <CIT>.

To solve the defects in the existing art, the object of the present disclosure is to provide a grass trimmer so that a user can install a grass trimmer rope quickly and easily.

To achieve the preceding object, the present disclosure provides the invention as claimed in the independent claim attached. Preferred embodiments of the invention are defined in dependent claims attached.

The beneficial effects of the present disclosure are that the user can quickly and easily install the grass trimmer rope to the grass trimmer head, and the user does not need to directly touch the grass trimmer head, so as to prevent the user's hands from being soiled.

A grass trimmer <NUM> in a first example shown in <FIG> is used for trimming lawns. Specifically, a user may operate the grass trimmer <NUM> to cut grass on the lawn or trim grass around shrubs or buildings. The grass trimmer <NUM> is installed with a grass trimmer rope <NUM>, and the grass trimmer rope <NUM> rotates at a high speed so that the grass is cut.

The grass trimmer <NUM> includes a front end device 400a, a connecting rod assembly <NUM>, and a rear end device 400b. The front end device 400a is disposed at a front end of the connecting rod assembly <NUM>, and the rear end device 400b is disposed at a rear end of the connecting rod assembly <NUM>. The connecting rod assembly <NUM> includes a connecting rod <NUM> and an auxiliary handle <NUM>. The connecting rod <NUM> is configured to connect the front end device 400a, the rear end device 400b, and the auxiliary handle <NUM>, and the connecting rod <NUM> basically extends along a direction of a first straight line <NUM>. In other examples, the connecting rod <NUM> may also extend along a curve. The auxiliary handle <NUM> is used for the user to hold in an auxiliary manner, and a position of the auxiliary handle <NUM> on the connecting rod <NUM> may be adjusted along the direction of the first straight line <NUM>. A direction along the first straight line <NUM> toward the front end device 400a is defined as the front, and a direction along the first straight line <NUM> toward the rear end device 400b is defined as the rear.

The rear end device 400b includes a main handle <NUM>, a rear housing <NUM>, and a circuit board assembly disposed in the rear housing <NUM>. The main handle <NUM> is for the user to hold. When the user operates the grass trimmer <NUM>, the main handle <NUM> and the auxiliary handle <NUM> may be respectively held by two hands so that the grass trimmer <NUM> is operated more stably. The main handle <NUM> is further provided with an operation switch 491a for activating and powering on the grass trimmer <NUM>. After powered on, the grass trimmer <NUM> can drive the grass trimmer rope <NUM> to rotate at a high speed so as to cut the grass. The rear housing <NUM> is integrally formed with the main handle <NUM>. In other examples, the rear housing <NUM> may also be provided separately from the main handle <NUM>. The rear housing <NUM> is further formed with a joint portion 492a, the joint portion 492a is configured to be connected to an energy device, the energy device is a battery pack, and the battery pack is configured to supply a power source to the grass trimmer <NUM>. In other examples, the joint portion 492a may also be connected to a cable, and the cable may be connected to a mains electricity grid. In other examples, the joint portion 492a may also be connected to other energy devices. For example, the joint portion 492a may be provided with a fuel tank, and the fuel in the fuel tank may supply power to the grass trimmer <NUM>.

As shown in <FIG> and <FIG>, the front end device 400a includes a grass trimmer head <NUM> and a drive device <NUM>, and the grass trimmer head <NUM> is used for installing the grass trimmer rope <NUM> so as to drive the grass trimmer rope <NUM> to rotate at a high speed. The drive device <NUM> is configured to drive the grass trimmer head <NUM> to rotate.

The front end device 400a further includes a shield <NUM> surrounding at least part of the drive device <NUM> or the grass trimmer head <NUM>. The shield <NUM> is configured to prevent grass clippings from being splashed on the user. The grass trimmer head <NUM> is used for installing the grass trimmer rope <NUM>. As shown in <FIG>, the grass trimmer head <NUM> includes a head housing <NUM> and a spool <NUM>, the spool <NUM> is used for the grass trimmer rope <NUM> to be wound around, and the head housing <NUM> is used for accommodating at least part of the spool <NUM>. A winding portion <NUM> is formed on the spool <NUM>, two threading elements <NUM> are connected to the head housing <NUM>, and two ends of the grass trimmer rope <NUM> pass through threading holes <NUM> on the threading elements <NUM>, respectively. A part of the grass trimmer rope <NUM> located in the head housing <NUM> is wound around the winding portion <NUM>. When the grass trimmer head <NUM> rotates at a high speed, the spool <NUM> and the head housing <NUM> drive the grass trimmer rope <NUM> to rotate at a high speed, and the rotating grass trimmer rope <NUM> can cut the grass.

In this example, the head housing <NUM> includes an upper housing <NUM> and a lower housing <NUM>, and the spool <NUM> is disposed between the upper housing <NUM> and the lower housing <NUM>. The upper housing <NUM> is further provided with a fan <NUM>. When the grass trimmer head <NUM> rotates, the head housing <NUM> drives the fan <NUM> to rotate, and the rotating fan <NUM> can generate a flowing airflow. The airflow can not only dissipate heat from the drive device <NUM>, but also flow in a direction away from the grass trimmer head <NUM> so as to prevent the front end device 400a from being entangled with grass clippings.

The drive device <NUM> is disposed on an upper side of the grass trimmer head <NUM> and configured to drive the grass trimmer head <NUM> to rotate. In this example, the drive device <NUM> is connected to the spool <NUM>, the drive device <NUM> drives the spool <NUM> to rotate about a first axis <NUM>, and a transmission mechanism is disposed between the spool <NUM> and the head housing <NUM>. In this example, the transmission mechanism includes a first driving portion <NUM> disposed on the spool <NUM> and a first mating portion <NUM> disposed on the head housing <NUM>. When the drive device <NUM> drives the spool <NUM> to rotate about the first axis <NUM>, the first driving portion <NUM> mates with the first mating portion <NUM> to drive the head housing <NUM> to rotate together with the spool <NUM> around the first axis <NUM> so that the grass trimmer <NUM> is in a grass trimming mode. In other examples, the drive device <NUM> may also be connected to the head housing <NUM>, the drive device <NUM> drives the head housing <NUM> to rotate, and through the first mating portion <NUM>, the head housing <NUM> drives the spool <NUM> to rotate together. In this example, when the grass trimmer <NUM> is in the grass trimming mode, the drive device <NUM> drives the grass trimmer head <NUM> to rotate about the first axis <NUM> in a first rotation direction <NUM>. As shown in <FIG>, the first rotation direction <NUM> may be a clockwise direction when viewed from top to bottom. It is to be understood that in other examples, the first rotation direction may also be a counterclockwise direction when viewed from top to bottom.

The front end device 400a further includes an operating device <NUM>, the operating device <NUM> is connected to the drive device <NUM>, and the operating device <NUM> includes an operating member <NUM> for the user to operate.

The grass trimmer <NUM> further has a winding mode. When the grass trimmer <NUM> is in the winding mode, the user operates the operating member <NUM> to make the operating member <NUM> move. At this time, movement of the operating member <NUM> is transmitted to the spool <NUM> or the head housing <NUM> through the drive device <NUM> so as to generate relative movement that is between the spool <NUM> and the head housing <NUM> and through which the grass trimmer rope <NUM> is wound around the spool <NUM>. Specifically, when the grass trimmer rope <NUM> is used up, the user needs to install a new grass trimmer rope <NUM> on the grass trimmer head <NUM>. At this time, the user may pass the grass trimmer rope <NUM> through the threading holes <NUM> to make a part of the grass trimmer rope <NUM> located in the head housing <NUM>, and then the user operates the operating member <NUM>. The movement of the operating member <NUM> is transmitted to the spool <NUM> through the drive device <NUM> so as to drive the spool <NUM> to rotate about the first axis <NUM> in a second rotation direction <NUM>, the spool <NUM> rotates relative to the head housing <NUM>, and the rotating spool <NUM> winds the grass trimmer rope <NUM> around the winding portion <NUM>. The second rotation direction <NUM> is opposite to the first rotation direction <NUM>. For example, the first rotation direction <NUM> is a clockwise direction, and the second rotation direction <NUM> is a counterclockwise direction. In this example, the operating member <NUM> moves to drive the spool <NUM> to rotate relative to the head housing <NUM> so that the user can wind the grass trimmer rope <NUM> around the spool <NUM> with less effort. On one hand, when winding the grass trimmer rope <NUM>, the user does not need to disassemble the spool <NUM> from the head housing <NUM> so that a winding effect is higher. On the other hand, the operation switch 491a installed on the main handle <NUM> does not need to be activated, that is, when the grass trimmer <NUM> is in the winding mode, the grass trimmer <NUM> does not need to consume the power of the energy device, and the battery pack does not need to output power at this time, thereby saving energy. Furthermore, the grass trimmer <NUM> is configured not to be activated, and only through mechanical movement of the operating device <NUM>, the movement may be mechanically transmitted to the spool <NUM> through the drive device <NUM>, so as to ensure the reliability of the winding, and no winding failure occurs. In addition, the movement of the operating member <NUM> is transmitted to the spool <NUM> through the drive device <NUM> without additionally disposing a transmission device for power transmission, which can further reduce a dimension of the grass trimmer <NUM> and reduce the manufacturing cost of the grass trimmer <NUM>.

As shown in <FIG>, the first driving portion <NUM> includes a driving surface 522a and an inclined surface 522b. When the spool <NUM> rotates along the first rotation direction <NUM>, the driving surface 522a is in contact with the first mating portion <NUM> so as to drive the head housing <NUM> to rotate with the spool <NUM>, and the grass trimmer <NUM> is in the grass trimming mode. When the spool <NUM> rotates along the second rotation direction <NUM>, the inclined surface 522b of the spool <NUM> is in contact with the first mating portion <NUM>, the inclined surface 522b cannot drive the head housing <NUM> to rotate with the spool <NUM>, and the inclined surface 522b passes over the first mating portion <NUM> so that the spool <NUM> can rotate relative to the head housing <NUM> along the second rotation direction <NUM>, and the grass trimmer <NUM> is in the winding mode at this time.

The grass trimmer <NUM> further includes a limiter <NUM> configured to restrict rotation of the head housing <NUM> along the second rotation direction <NUM>, the limiter <NUM> is a one-way bearing connected to the upper housing <NUM>, and the one-way bearing allows the head housing <NUM> to rotate along the first rotation direction <NUM>, but the one-way bearing does not allow the head housing <NUM> to rotate along the second rotation direction <NUM>. In this manner, when the spool <NUM> rotates along the first rotation direction <NUM>, the one-way bearing does not restrict the rotation of the head housing <NUM>, and the head housing <NUM> can rotate together with the spool <NUM>. When the spool <NUM> rotates along the second rotation direction <NUM>, the one-way bearing restricts the rotation of the head housing <NUM> along the second rotation direction <NUM>, and the spool <NUM> cannot drive the head housing <NUM> to rotate together. At this time, the spool <NUM> moves relative to the head housing <NUM>, and thus the grass trimmer rope <NUM> is wound around the spool <NUM>. In other examples, the limiter <NUM> may also be another limiting device with two states. In one state, the limiter <NUM> allows the head housing <NUM> to rotate, and in the other state, the limiter <NUM> restricts the rotation of the head housing <NUM>.

In this example, the drive device <NUM> includes a housing <NUM> and a motor disposed in the housing <NUM>, and the motor is specifically an electric motor <NUM>. The battery pack can supply power to the electric motor <NUM>, and the circuit board assembly is electrically connected to the electric motor <NUM> so as to control the electric motor <NUM>. The operation switch 491a is configured to activate the electric motor <NUM>. When the grass needs to be cut, the user presses the operation switch 491a, the operation switch 491a powers on the electric motor <NUM>, and the electric motor <NUM> drives the spool <NUM> to rotate about the first axis <NUM> along the first rotation direction <NUM>. At this time, the grass trimmer head <NUM> rotates about the first axis <NUM> at a high speed, and the grass trimmer <NUM> is in the grass trimming mode. When the grass trimmer rope <NUM> needs to be wound, the user operates the operating member <NUM>, and the movement of the operating member <NUM> is mechanically transmitted to the spool <NUM> through the electric motor <NUM> so as to drive the spool <NUM> to rotate about the first axis <NUM> along the second rotation direction <NUM> so that the spool <NUM> moves relative to the head housing <NUM>, and the grass trimmer <NUM> is in the winding mode. When the grass trimmer <NUM> is in the winding mode, the operation switch 491a is not operated, the electric motor <NUM> is not powered on, and only the electric motor <NUM> mechanically transmits the movement of the operating member <NUM> to the spool <NUM>, thereby reducing the failure possibility of the winding mode and reducing the power consumed by the electric motor <NUM>.

The electric motor <NUM> includes a motor shaft <NUM>, the motor shaft <NUM> extends along the first axis <NUM>, the motor shaft <NUM> can rotate about the first axis <NUM>, and the motor shaft <NUM> is connected to the spool <NUM>. In other examples, the motor shaft <NUM> may also be connected to the head housing <NUM>. In other examples, the motor shaft <NUM> may also be configured to rotate about an axis parallel to the first axis <NUM>. In other examples, the motor shaft <NUM> may also be configured to rotate about an axis inclined relative to the first axis <NUM>.

The housing <NUM> accommodates at least part of the electric motor <NUM>, the grass trimmer head <NUM> is disposed outside the housing <NUM>, and the motor shaft <NUM> extends from an inside of the housing <NUM> to an outside of the housing <NUM> and into the grass trimmer head <NUM>. The housing <NUM> is further formed with a connecting hole <NUM> into which the connecting rod <NUM> is inserted to be connected to the housing <NUM> so that the front end device 400a is connected to a front end of the connecting rod <NUM>. The other end of the connecting rod <NUM> is inserted into the main handle <NUM> and connected to the rear end device 400b.

The operating device <NUM> is connected to the housing <NUM>, and the operating member <NUM> is connected to an outer wall of the housing <NUM> so that the operating member <NUM> is located on the upper side of the grass trimmer head <NUM>, which is convenient for the user to operate. The operating member <NUM> specifically includes an operating portion <NUM> for the user to operate, and the operating portion <NUM> is disposed on the upper side of the grass trimmer head <NUM>. In this manner, when the user operates the operating member <NUM>, the user's hands can be kept away from the grass trimmer head <NUM> and not touch the grass trimmer head <NUM> so that the hands are not soiled and the subsequent grass trimming operation is not affected. In addition, the operating member <NUM> is disposed on the upper side of the grass trimmer head <NUM> so that the operating member <NUM> can be prevented from being entangled with grass clippings and the operating member <NUM> can be prevented from being stained with soil.

The front end device 400a further includes a clutch device <NUM> disposed between the operating device <NUM> and the drive device <NUM>. In this example, the clutch device <NUM> may connect the operating member <NUM> to the motor shaft <NUM>. The clutch device <NUM> is disposed at an end of the motor <NUM> away from the grass trimmer head <NUM>. As shown in <FIG> and <FIG>, the clutch device <NUM> has a first state and a second state. In the case where the clutch device <NUM> is in the first state, the movement of the operating member <NUM> is transmitted to the drive device <NUM> through the clutch device <NUM>, and the grass trimmer <NUM> enters the winding mode. In the case where the clutch device <NUM> is in the second state, the clutch device <NUM> disconnects power transmission between the operating member <NUM> and the drive device <NUM>, and the grass trimmer <NUM> exits the winding mode and enters the grass trimming mode.

When the clutch device <NUM> is in the first state, the clutch device <NUM> connects the operating device <NUM> to the motor shaft <NUM>, and the movement of the operating member <NUM> may be transmitted to the spool <NUM> through the motor shaft <NUM> at this time. When the clutch device <NUM> is in the second state, the clutch device <NUM> disconnects power transmission between the operating device <NUM> and the motor shaft <NUM>, and the movement of the operating member <NUM> cannot be transmitted to the motor shaft <NUM> through the clutch device <NUM> at this time.

In fact, the operating member <NUM> may move to a first position and a second position relative to the housing <NUM>. When the operating member <NUM> is at the first position, the operating member <NUM> drives the clutch device <NUM> to switch to the first state. When the operating member <NUM> moves to the second position, the operating member <NUM> drives the clutch device <NUM> to switch to the second state. That is, the first position of the operating member <NUM> corresponds to the first state of the clutch device <NUM>, and the second position of the operating member <NUM> corresponds to the second state of the clutch device <NUM>.

As shown in <FIG> and <FIG>, when the user needs to wind the rope, the operating member <NUM> may move from the second position to the first position. At this time, the operating member <NUM> drives the clutch device <NUM> to switch from the second state to the first state. The clutch device <NUM> connects the operating member <NUM> to the motor shaft <NUM> and can achieve power transmission between the operating member <NUM> and the motor shaft <NUM>, and the operating member <NUM> may mechanically drive the motor shaft <NUM> to rotate. At this time, the user holds the operating member <NUM> and rotates the operating member <NUM> about the first axis <NUM>, the clutch device <NUM> also rotates about the first axis <NUM> along with the operating member <NUM>, and then the clutch device <NUM> drives the motor shaft <NUM> to rotate about the first axis <NUM>, and the rotating motor shaft <NUM> drives the spool <NUM> to rotate relative to the head housing <NUM> along the second rotation direction <NUM>, thereby winding the grass trimmer rope <NUM> around the spool <NUM>.

After the grass trimmer rope <NUM> is wound, the user needs to use the grass trimmer <NUM> to trim the grass. At this time, the user releases the operating member <NUM> or drives the operating member <NUM> to be reset to the second position, the clutch device <NUM> is also reset to the second state, and the clutch device <NUM> disconnects the power transmission between the operating member <NUM> and the motor shaft <NUM>. At this time, the user turns on the operation switch 491a, the electric motor <NUM> is powered on and starts to operate, the motor shaft <NUM> rotates, and the rotating motor shaft <NUM> drives the grass trimmer head <NUM> to rotate at a high speed so as to trim the grass. At this time, the grass trimmer <NUM> is in the grass trimming mode. When the clutch device <NUM> is at the second position and the motor shaft <NUM> rotates, the clutch device <NUM> does not transmit movement of the motor shaft <NUM> to the operating member <NUM>, so the operating member <NUM> remains stationary at this time.

The clutch device <NUM> is provided so that the grass trimmer head <NUM> can be switched between the grass trimming mode and the winding mode. When the grass trimmer <NUM> trims the grass, the operating member <NUM> does not move; and when the rope in the grass trimmer <NUM> is wound, the electric motor <NUM> is not powered on. Therefore, the grass trimming mode and the winding mode of the grass trimmer <NUM> do not interfere with each other.

As shown in <FIG>, the operating member <NUM> may rotate relative to the housing <NUM> around a second axis <NUM>. When rotating relative to the housing <NUM> around the second axis <NUM>, the operating member <NUM> may rotate to the second position shown in <FIG>, and the operating member <NUM> may also rotate relative to the housing <NUM> around the second axis <NUM> to the first position shown in <FIG>. As shown in <FIG> and <FIG>, when the operating member <NUM> rotates to the second position, the clutch device <NUM> is reset to the second state, and the clutch device <NUM> disconnects power transmission between the operating member <NUM> and the electric motor <NUM>. As shown in <FIG> and <FIG>, when the operating member <NUM> rotates to the first position, the operating member <NUM> drives the clutch device <NUM> to switch to the first state, and the clutch device <NUM> connects the operating member <NUM> to the electric motor <NUM>. At this time, the clutch device <NUM> may achieve power transmission between the operating member <NUM> and the motor shaft <NUM>.

The second axis <NUM> is perpendicular to the first axis <NUM>. The housing <NUM> is provided with a mount <NUM>, and the operating member <NUM> is installed to the mount <NUM> and may rotate relative to the mount <NUM> around the second axis <NUM>.

The housing <NUM> includes a surrounding portion <NUM> and a top portion <NUM>, the surrounding portion <NUM> surrounds the electric motor <NUM>, the top portion <NUM> is disposed on an upper side of the electric motor <NUM>, and the top portion <NUM> is connected to an upper side of the surrounding portion <NUM>. The mount <NUM> for installing the operating member <NUM> is disposed on the top portion <NUM> so that the operating member <NUM> is connected to the top portion <NUM>. The operating member <NUM> may rotate relative to the top portion <NUM> around the second axis <NUM> to move to the first position and the second position. The operating member <NUM> may also drive the mount <NUM> to rotate relative to the surrounding portion <NUM> about the first axis <NUM>. In this example, the mount <NUM> is fixedly connected to the top portion <NUM>, the mount <NUM> rotates in sync with the top portion <NUM>, and a whole formed by the operating member <NUM>, the mount <NUM>, and the top portion <NUM> may rotate relative to the surrounding portion <NUM> about the first axis <NUM>. In other examples, the mount may also be rotatably connected to the top portion. When the operating member <NUM> moves to the first position, the user operates the operating member <NUM> to rotate the operating member <NUM> about the first axis <NUM>, and at this time, the operating member <NUM> drives the mount <NUM> and the top portion <NUM> to rotate relative to the surrounding portion <NUM> around the first axis <NUM>. The clutch device <NUM> rotates in sync with the mount <NUM>. When the operating member <NUM> is at the first position, the clutch device <NUM> is connected to the motor shaft <NUM>, the operating member <NUM> drives the mount <NUM> to rotate about the first axis <NUM>, and the clutch device <NUM> also rotates about the first axis <NUM> along with the mount <NUM> so that the clutch device <NUM> drives the motor shaft <NUM> to rotate about the first axis <NUM>. At this time, the clutch device <NUM> transmits rotation of the operating member <NUM> to the motor shaft <NUM> so that the spool <NUM> may rotate relative to the head housing <NUM>, thereby achieving winding.

The clutch device <NUM> specifically includes a clutch element <NUM> and a reset element <NUM>. The clutch element <NUM> may move to a transmission position and a non-transmission position. The reset element <NUM> is a spring that biases the clutch element <NUM> to move toward the non-transmission position. When the operating member <NUM> is operated by the user to move from the second position to the first position, the operating member <NUM> drives the clutch element <NUM> to move from the non-transmission position to the transmission position, and the clutch device <NUM> switches from the second state to the first state. That is, when the clutch element <NUM> is at the transmission position, the clutch device <NUM> is in the first state; and when the clutch element <NUM> is in the non-transmission position, the clutch device <NUM> is in the second state. Specifically, the operating member <NUM> is formed with a driving portion <NUM> which is a cam portion. When the operating member <NUM> moves from the second position to the first position, the driving portion <NUM> drives the clutch element <NUM> to move along the first axis <NUM> toward the motor shaft <NUM> so that the clutch element <NUM> is finally connected to the motor shaft <NUM>, and the clutch device <NUM> switches to the first state at this time. When the clutch element <NUM> moves to the non-transmission position, the clutch element <NUM> is disengaged from the motor shaft <NUM>, and the clutch device <NUM> switches to the second state. A position of the mount <NUM> remains fixed along the first axis <NUM>. When the operating member <NUM> moves relative to the mount <NUM> around the second axis <NUM> from the second position to the first position, the driving portion <NUM> is to be in contact with the clutch element <NUM> and then drives the clutch element <NUM> to slide relative to the mount <NUM>. The mount <NUM> rotates in sync with the clutch element <NUM>, the mount <NUM> is formed with a mounting groove 612a, and the clutch element <NUM> includes an arm 651a which can be inserted into the mounting groove 612a. The mounting groove 612a mates with the arm 651a, the mounting groove 612a rotates in sync with the arm 651a about the first axis <NUM>, and the mounting groove 612a also allows the arm 651a to slide along a direction of the first axis <NUM>.

The reset element <NUM> generates a biasing press that drives the clutch element <NUM> to move toward the non-transmission position. When the operating member <NUM> is reset from the first position to the second position, the operating member <NUM> allows the clutch element <NUM> to be reset to the non-transmission position. At this time, the reset element <NUM> drives the clutch element <NUM> to be reset to the non-transmission position so that it can be ensured that when the user does not operate the operating member <NUM>, the clutch element <NUM> remains at the non-transmission position and does not affect the grass trimming of the grass trimmer <NUM>. Specifically, the reset element <NUM> is a spring, the spring abuts against the clutch element <NUM>, and the biasing press generated by the spring biases the clutch element <NUM> to move in a direction away from the motor shaft <NUM>.

The clutch element <NUM> is formed with a first transmission portion 651b, the motor shaft <NUM> is formed with or connected to a second transmission portion 621a, and the first transmission portion 651b and the second transmission portion 621a can mate with each other. Specifically, the clutch element <NUM> is formed with a transmission hole, a hole wall of the transmission hole is formed with the first transmission portion 651b, and the first transmission portion 651b is first meshing teeth. The motor shaft <NUM> is fixedly connected to a driving wheel, the driving wheel is formed with the second transmission portion 621a, and the second transmission portion 621a is second meshing teeth. When the clutch element <NUM> moves to the transmission position, the driving wheel extends into the transmission hole, the first transmission portion 651b is meshed with the second transmission portion 621a, and the clutch element <NUM> can drive the motor shaft <NUM> to rotate. When the clutch element <NUM> moves to the non-transmission position, the first transmission portion 651b is disengaged from the second transmission portion 621a.

In this example, the operating member <NUM> is at least partially disposed on an upper side of the drive device <NUM> so that the user operates more conveniently, and when the user winds the rope, the user's hands can be kept away from the grass trimmer head <NUM> and the arm 651a can be prevented from being soiled.

Specifically, the operating member <NUM> further includes a connecting portion <NUM> used for connecting the operating member <NUM> to the mount <NUM>. The operating member <NUM> is disposed at least partially on the upper side of the grass trimmer head <NUM>. Along the direction of the first axis <NUM>, a distance L1 between the operating member <NUM> and a lower end surface of the grass trimmer head <NUM> is greater than or equal to <NUM> and less than or equal to <NUM>. In this manner, when the user operates the operating portion <NUM>, a certain distance exists between the user's hands and the lower end surface of the grass trimmer head <NUM> so that the user's hands do not touch the ground or the lower end surface of the grass trimmer head <NUM>. When the grass trimmer <NUM> switches from the grass trimming mode to the winding mode, the position of the operating portion <NUM> changes.

A part other than the operating member <NUM> of the grass trimmer <NUM> is defined as a main body <NUM>. The main body <NUM> includes the rear end device 400b, the connecting rod assembly <NUM>, the auxiliary handle <NUM>, the drive device <NUM>, and the grass trimmer head <NUM>. In this example, the operating member <NUM> is fixedly installed to the main body <NUM>. Specifically, the operating member <NUM> is installed to the housing <NUM>. In this manner, even when the grass trimmer <NUM> is in the grass trimming mode, the operating member <NUM> is still installed to the main body <NUM>. Therefore, regardless of whether the grass trimmer <NUM> is in the winding mode or the grass trimming mode, the operating member <NUM> is installed on the housing <NUM>, and the operating member <NUM> will never be disengaged from the main body <NUM> so that the operating member <NUM> can be prevented from being lost.

In this example, the operating member <NUM> is fixedly installed to the mount <NUM>. Apparently, in other examples, the operating member may also be detachably installed to the mount. Alternatively, in other examples, the operating member may also be non-detachably installed to the mount.

In other examples, when the operating member <NUM> is detachably installed to the mount <NUM>, other parts of the main body <NUM> may further be provided with a receiving groove capable of receiving the operating member <NUM>. When the grass trimmer <NUM> is in the winding mode, the operating member <NUM> is installed to the mount <NUM>. When the grass trimmer <NUM> is in the grass trimming mode, the operating member <NUM> is installed to the receiving groove. In this manner, even when the grass trimmer <NUM> is in the grass trimming mode, the operating member <NUM> may still be installed to the main body <NUM> so that the operating member <NUM> can be prevented from being lost.

As shown in <FIG>, the housing <NUM> is further formed with an accommodation groove <NUM>, and when the operating member <NUM> is at the second position, the operating portion <NUM> is inserted into the accommodation groove <NUM>. When the user does not operate the operating member <NUM>, the accommodation groove <NUM> can restrict the operating member <NUM> from being disengaged from the accommodation groove <NUM> so that the operating member <NUM> can be prevented from being shaken.

As shown in <FIG> and <FIG>, the operating portion <NUM> further includes a roller 711a, and the roller 711a is rotatably connected to the connecting portion <NUM> so that the user may operate the operating member <NUM> by operating the roller 711a, thereby making the user's operation more labor-saving.

In this example, when the grass trimmer <NUM> is in the winding mode, the user rotates the operating member <NUM> about the first axis <NUM>, and a distance L2 between the operating portion <NUM> and the first axis <NUM> is greater than or equal to <NUM> and less than or equal to <NUM>. In this manner, the user can save efforts when rotating the operating member <NUM>, and at the same time, the operating member <NUM> can be prevented from being too large to affect a dimension of the front end device 400a.

As shown in <FIG>, the grass trimmer <NUM> in a second example includes a connecting rod <NUM>, a rear end device, and a front end device <NUM>. The front end device <NUM> includes a housing <NUM>, an electric motor <NUM>, a drive device <NUM>, and a grass trimmer head <NUM>. The housing <NUM> accommodates the drive device <NUM> and the electric motor <NUM>, the drive device <NUM> is disposed between the electric motor <NUM> and the grass trimmer head <NUM> to connect the electric motor <NUM> to the grass trimmer head <NUM>, and the drive device <NUM> transmits power outputted by the electric motor <NUM> to the grass trimmer head <NUM>. The grass trimmer head <NUM> includes a spool 734a and a head housing 734b, and the electric motor <NUM> drives the spool 734a or the head housing 734b through the drive device <NUM> so that the grass trimmer head <NUM> rotates about the first axis. The front end device <NUM> further includes an operating device <NUM> configured to be connected to the drive device <NUM>. The operating device <NUM> includes an operating member 735a connectable to the drive device <NUM>, and movement of the operating member 735a is transmitted to the spool 734a or the head housing 734b through the drive device <NUM> without the need to transmit power to the spool 734a or the head housing 734b through the electric motor <NUM>. When the grass trimmer <NUM> is in the winding mode, the operating member 735a rotates to drive the drive device <NUM> to rotate, and the drive device <NUM> drives the spool 734a or the head housing 734b to rotate so as to generate relative movement between the spool 734a and the head housing 734b. When the grass trimmer <NUM> is in the grass trimming mode, the operating member 735a is disengaged from the drive device <NUM>, the electric motor <NUM> drives the drive device <NUM> to rotate, and the drive device <NUM> drives the spool 734a or the head housing 734b to drive the grass trimmer head <NUM> to rotate.

<FIG> is a front end device 100a of a grass trimmer according to a third example. The grass trimmer in the third example has the same rear end device and connecting rod as the grass trimmer in the first example. The front end device 100a in the third example is the same as the front end device 400a in the first example. A function of a drive device <NUM> in the third example is basically the same as the drive device in the first example, and a difference lies in a specific structure of the drive device <NUM> being different from that in the first example. An operating device <NUM> in the third example may achieve basically the same function as the operating device <NUM> in the first example, and a difference is that a specific structure of the operating device <NUM> in the third example is different from a specific structure of the operating device <NUM> in the first example.

As shown in <FIG>, the front end device 100a includes a grass trimmer head <NUM> and the drive device <NUM>. The grass trimmer head <NUM> is configured to trim the grass, and the drive device <NUM> is configured to drive the grass trimmer head <NUM> to rotate about a rotation axis <NUM>.

As shown in <FIG>, the drive device <NUM> includes a motor <NUM>, a motor housing <NUM>, and a transmission assembly <NUM>. The motor <NUM> is configured to drive the grass trimmer head <NUM> to rotate, and the motor <NUM> may specifically include a motor shaft <NUM>. In this example, the motor <NUM> also rotates about the rotation axis <NUM>. Apparently, it is to be understood that in other examples, the motor shaft <NUM> may not rotate about the rotation axis <NUM>. For example, the motor shaft <NUM> may rotate about a straight line parallel to the rotation axis <NUM>, and the motor shaft <NUM> may also rotate about a straight line perpendicular to the rotation axis <NUM>. The motor housing <NUM> is used for accommodating the motor <NUM>. The motor housing <NUM> may be formed with an accommodation cavity in which the motor <NUM> is disposed. The transmission assembly <NUM> is configured to transmit power between the motor <NUM> and the grass trimmer head <NUM>.

The motor <NUM> is specifically a electric motor, which is further a brushless electric motor, and further, the electric motor is an outer rotor brushless electric motor. The electric motor includes a rotor assembly and a stator assembly, where the rotor assembly includes a rotor shaft, and the rotor shaft is the motor shaft <NUM>.

The grass trimmer head <NUM> is configured to drive the grass trimmer rope <NUM> to rotate at a high speed to cut vegetation, and the grass trimmer head <NUM> includes a head housing <NUM> and a spool <NUM>. The spool is used for the grass trimmer rope <NUM> to be wound around, and the head housing <NUM> is used for accommodating the spool <NUM>. The spool <NUM> is disposed in an accommodation space surrounded by the head housing <NUM>.

The front end device 100a further includes the user-operable operating device <NUM> disposed on the drive device <NUM>, and the operating device <NUM> may be operated to wind the rope.

Further, the operating device <NUM> includes a winding state and a non-winding state. When the operating device <NUM> is in the winding state, the operating device <NUM> is in a transmission connection with the motor <NUM> to drive the grass trimmer head <NUM> so that the spool <NUM> rotates relative to the head housing <NUM> about the rotation axis <NUM> as an axis, thereby winding the rope. When the operating device <NUM> is in the non-winding state, the operating device <NUM> is disengaged from the motor <NUM>.

Specifically, the grass trimmer has an automatic winding mode, a manual winding mode, and a grass trimming mode. Apparently, it can also be considered that the grass trimmer head <NUM> has an automatic winding mode, a manual winding mode, and a grass trimming mode. When the grass trimmer head <NUM> is in the automatic winding mode, the motor <NUM> may drive the spool <NUM> to rotate relative to the head housing <NUM> about the rotation axis <NUM> along the first rotation direction, thereby automatically winding the grass trimmer rope <NUM> around the spool <NUM>. When the grass trimmer head <NUM> is in the manual winding mode, the operating device <NUM> is in the winding state, the user may rotate the spool <NUM> relative to the head housing <NUM> about the rotation axis <NUM> along the first rotation direction through the operating device <NUM>, and the grass trimmer rope <NUM> may be wound around the spool <NUM>. When the user activates the motor <NUM> by operating the operation switch, the motor <NUM> can drive the spool <NUM> to rotate about the rotation axis <NUM> along the second rotation direction so that the grass trimmer is in the grass trimming mode. In this example, when viewed from the motor <NUM> to the grass trimmer head <NUM>, the first rotation direction may be regarded as a counterclockwise direction, and correspondingly, the second rotation direction may be regarded as a clockwise direction, but apparently it is not limited thereto. It is to be understood that in other examples, the motor shaft <NUM> may also be connected to the head housing <NUM> to drive the head housing <NUM> to rotate; in this manner, when the grass trimmer head <NUM> is in the automatic winding mode, the motor <NUM> drives the head housing <NUM> to rotate so that the spool <NUM> rotates relative to the head housing <NUM> along the first rotation direction, thereby automatically winding the grass trimmer rope <NUM> around the spool <NUM>. Similarly, the operating device <NUM> may be connected to the head housing <NUM>; when the grass trimmer head <NUM> is in the manual winding mode, the user operates the operating device <NUM> to drive the head housing <NUM> to rotate so that the spool <NUM> rotates relative to the head housing <NUM> along the first rotation direction, thereby winding the grass trimmer rope <NUM> around the spool <NUM>.

In this manner, the grass trimmer head <NUM> may not only transmit power from the motor <NUM> to the spool <NUM>, thereby automatically winding the grass trimmer rope <NUM>, but also transmit the power from the operating device <NUM> to the spool <NUM>, thereby winding the grass trimmer rope <NUM> around the spool <NUM> so that the user may either automatically wind the grass trimmer rope <NUM> by triggering the operation switch, or manually wind the grass trimmer rope <NUM> through the operating device <NUM>, and thus a manual and automatic integrated grass trimmer is truly provided. In this manner, on the one hand, when the user rotates the operating device <NUM> to wind the grass trimmer rope <NUM>, the user may feel fatigued. At this time, the user may operate the operation switch so as to automatically wind the grass trimmer rope <NUM> around the spool <NUM>, thereby facilitating the operation of the user and improving the operation efficiency. In addition, when the automatic winding mode of the grass trimmer fails, the user may also manually wind the grass trimmer rope <NUM> around the spool <NUM> through the operating device <NUM>, thereby improving the reliable performance of the grass trimmer; and the problem of the tangled rope and dirty hands caused by the hands in contact with the grass trimmer head when the rope is manually wound can be avoided, thereby improving the winding speed and the user experience and improving the operation efficiency.

The operating device <NUM> specifically includes a crank handle <NUM> and a rotary button <NUM>. The crank handle <NUM> is hinged on a top of the rotary button <NUM>, and the crank handle <NUM> is used for pressing the rotary button <NUM> downward when the operating device <NUM> is in the winding state so that the rotary button <NUM> is connected to the motor shaft <NUM> of the motor <NUM>, and the crank handle <NUM> is rotated by an external force, thereby winding the rope; when the operating device <NUM> is in the non-winding state, the rotary button <NUM> and the motor shaft <NUM> are in a separated state. Specifically, the crank handle <NUM> may rotate from a vertical position (a position parallel to the rotation axis <NUM>) to a horizontal position. When the crank handle <NUM> is at the vertical position, the crank handle <NUM> is pressed downward so as to drive the rotary button <NUM> downward to be connected to the motor shaft <NUM>. It is to be understood that when the crank handle <NUM> is at an inclined position, the crank handle <NUM> may also be pressed downward, but the operation efficiency is low.

Further, the operating device <NUM> further includes an elastic reset member <NUM>, two ends of which act on the rotary button <NUM> and the motor housing <NUM>, respectively. In the winding state, the elastic reset member <NUM> is in a compressed state; in the non-winding state, the rotary button <NUM> and the motor shaft <NUM> are in a separated state under the action of the elastic reset member <NUM>. The elastic reset member <NUM> is provided so that the operating device <NUM> can quickly switch between the winding state and the non-winding state, and the structure is simple, easy to implement, and low in cost.

The motor <NUM> further includes a shaft sleeve <NUM>. The shaft sleeve <NUM> is sleeved on a top of the motor shaft <NUM> and can drive the motor shaft <NUM> to rotate. In the winding state, the rotary button <NUM> is connected to the shaft sleeve <NUM> to achieve the transmission connection with the motor shaft <NUM>; in the non-winding state, the rotary button <NUM> and the shaft sleeve <NUM> are in a separated state. The shaft sleeve <NUM> is provided so that the motor shaft <NUM> can be avoided from being worn, and the service life of the motor shaft <NUM> can be prolonged.

The operating device <NUM> further includes an annular cover plate <NUM>, the annular cover plate <NUM> is connected to a top of the motor housing <NUM> and forms an accommodation cavity with the motor casing <NUM>, the rotary button <NUM> is located in the accommodation cavity, and the crank handle <NUM> is at least partially located outside the annular cover plate <NUM> so that the crank handle <NUM> is operable. When the operating device <NUM> is in the non-winding state, the rotary button <NUM> and the shaft sleeve <NUM> of the motor shaft <NUM> are in a separated state under the action of the elastic reset member <NUM>. When the operating device <NUM> is in the winding state, the user needs to turn the crank handle <NUM> to the vertical position, the rotary button <NUM> is pressed through the crank handle <NUM> until the rotary button <NUM> mates with the shaft sleeve <NUM> on the motor shaft <NUM>, and then the crank handle <NUM> is rotated, thereby winding the rope. After a winding operation is completed, the crank handle <NUM> is released and placed at the horizontal position.

Further, the annular cover plate <NUM> is provided with a positioning groove <NUM>, one end of the crank handle <NUM> is hinged to the rotary button <NUM>, and the other end of the crank handle <NUM> may be lifted to the vertical position or placed flat at the horizontal position to be clamped in the positioning groove <NUM>. The positioning groove <NUM> is provided so that it is convenient to store the crank handle <NUM>. Furthermore, a hand-locking groove <NUM> is disposed on a side of an outer circumference of the annular cover plate <NUM> away from a position where the crank handle <NUM> is hinged to the rotary button <NUM>, the hand-locking groove <NUM> communicates with the positioning groove <NUM>, and the hand-locking groove <NUM> is provided, which is convenient for the hands to lift the crank handle <NUM>.

Preferably, the rotary button <NUM> has a T-shaped cross section and includes a limiting portion <NUM> and a rotating portion <NUM> that are vertically connected. The crank handle <NUM> is hinged to a top surface of the limiting portion <NUM>. In the non-winding state, under the action of the elastic reset member <NUM>, an upper surface of the limiting portion <NUM> abuts against an inner top surface of the annular cover plate <NUM>, that is, the inner top surface of the annular cover plate <NUM> has a certain limiting effect on the rotary button <NUM>; in the winding state, under the pressing action of the crank handle <NUM>, a certain distance exists between the limiting portion <NUM> and the inner top surface of the annular cover plate <NUM>. The rotating portion <NUM> is connected to a lower surface of the limiting portion <NUM>, and the rotating portion <NUM> is configured to be connected to the shaft sleeve <NUM>. Specifically, the rotating portion <NUM> is clamped to the shaft sleeve <NUM>.

Further, a middle part of the rotating portion <NUM> is provided with a clamping hole, and the shaft sleeve <NUM> is clamped to the clamping hole. Preferably, the clamping hole is a special-shaped hole, and an outer peripheral shape of the shaft sleeve <NUM> is adapted to a shape of the special-shaped hole so that the shaft sleeve <NUM> may rotate with the rotating portion <NUM>. A special-shaped structure is provided so that a connector is not provided, the cost is saved, and the reliability is relatively high.

The elastic reset member <NUM> is sleeved on an outer circumference of the rotating portion <NUM>, a limiting groove is disposed on the motor housing <NUM>, an upper end of the elastic reset member <NUM> abuts between the limiting portion <NUM> and the rotating portion <NUM>, and a lower end of the elastic reset member <NUM> is located in the limiting groove. Preferably, the elastic reset member <NUM> is a pagoda-shaped spring. The pagoda-shaped spring has advantages of a small volume and a large load, is suitable for small spaces, and has a certain shock absorption effect so that a smooth winding process can be ensured.

The above illustrates and describes basic principles, main features, and advantages of the present disclosure. motor includes a rotor assembly and a stator assembly, where the rotor assembly includes a rotor shaft, and the rotor shaft is the motor shaft <NUM>.

Preferably, the rotary button <NUM> has a T-shaped cross section and includes a limiting portion <NUM> and a rotating portion <NUM> that are vertically connected. The crank handle <NUM> is hinged to a top surface of the limiting portion <NUM>. in the non-winding state, under the action of the elastic reset member <NUM>, an upper surface of the limiting portion <NUM> abuts against an inner top surface of the annular cover plate <NUM>, that is, the inner top surface of the annular cover plate <NUM> has a certain limiting effect on the rotary button <NUM>; in the winding state, under the pressing action of the crank handle <NUM>, a certain distance exists between the limiting portion <NUM> and the inner top surface of the annular cover plate <NUM>. The rotating portion <NUM> is connected to a lower surface of the limiting portion <NUM>, and the rotating portion <NUM> is configured to be connected to the shaft sleeve <NUM>. Specifically, the rotating portion <NUM> is clamped to the shaft sleeve <NUM>.

Claim 1:
A grass trimmer (<NUM>, <NUM>), comprising:
a grass trimmer head (<NUM>, <NUM>, <NUM>) comprising a spool (<NUM>, 734a, <NUM>) used for a grass trimmer rope (<NUM>, <NUM>) to be wound around, and a head housing (<NUM>, 734b, <NUM>) for accommodating at least part of the spool;
a drive device (<NUM>, <NUM>, <NUM>) configured to drive the grass trimmer head to rotate; and
an operating member (<NUM>, 735a) connected to the drive device and comprising an operating portion (<NUM>) for a user to operate;
wherein the grass trimmer has a winding mode, and when the grass trimmer is in the winding mode, movement of the operating member is transmitted to the spool or the head housing so as to generate relative movement that is between the spool and the head housing and through which the grass trimmer rope is wound around the spool, wherein
the drive device includes an electric motor (<NUM>, <NUM>, <NUM>) configured to drive the spool or the head housing, and the electric motor includes a motor shaft (<NUM>, <NUM>); in the case where the grass trimmer is in the winding mode, the electric motor is not powered on, and the operating member mechanically drives the motor shaft to rotate; and the grass trimmer further comprises a grass trimming mode, when the grass trimmer is in the grass trimming mode, the electric motor is powered on, starts to operate, and drives the grass trimmer head to rotate,
characterized in that
the movement of the operating member is transmitted to the spool or the head housing through the drive device.