Patent Description:
This application relates to a grass cutting head.

As a lawn trimming tool among garden tools, grass trimmers have received widespread attention. Typically, the grass trimmer includes a grass cutting head, which is provided therein with a spool around which a grass cutting line is wound. In the related art, to wind the grass cutting line up around the spool, the user usually needs to remove the spool to manually wind the grass cutting line, which is time-consuming and laborious, reducing the work efficiency. Accordingly, a grass cutting head is also available on the market that can wind the grass cutting line around the spool without the need to remove the spool. However, the user still needs to manually align the outer threading hole of the grass cutting head with the inner threading hole of the spool in order to achieve winding. Due to factors such as professionalism and operation environment, the user needs to spend a lot of effort to align the inner threading hole of the spool with the outer threading hole of the grass cutting head during threading. Furthermore, because the grass cutting line is relatively soft, it is impossible to quickly pass the grass cutting line through one outer threading hole and out of another outer threading hole during threading, thus making it time-consuming and laborious and reducing the user experience. As a result, the user still needs to remove the spool regularly to achieve the winding purpose, which reduces the work efficiency.

The objective technical problem is solved by means of a grass cutting head having the features of claim <NUM>.

<FIG> is a schematic view of a grass trimmer <NUM> according to an embodiment. In this embodiment, the grass trimmer <NUM> includes a grass cutting head <NUM>, a driving apparatus <NUM>, and an operating apparatus <NUM>.

As illustrated in <FIG> and <FIG>, the driving apparatus <NUM> drives the grass cutting head <NUM> to rotate around a first axis <NUM> and then drives a grass cutting line <NUM> to rotate and cut vegetation. The user operates the operating apparatus <NUM> to control the grass trimmer <NUM>.

The driving apparatus <NUM> includes a motor and a driving shaft. The driving shaft is connected to the grass cutting head <NUM> to drive the grass cutting head <NUM> to rotate around the first axis <NUM>.

As illustrated in <FIG> and <FIG>, the grass cutting head <NUM> includes a spool <NUM> and a head housing <NUM>. The grass cutting line <NUM> is wound around the spool <NUM>. The spool <NUM> is accommodated in the head housing <NUM>. The spool <NUM> is provided with a winding groove <NUM> (see <FIG>). As illustrated in <FIG> and <FIG>, the head housing <NUM> is provided with an outer threading hole <NUM> through which the grass cutting line <NUM> passes. The outer threading hole <NUM> is further provided with an eyelet member <NUM>. In an embodiment, the head housing <NUM> includes a first housing <NUM> and a second housing <NUM>, which facilitates assembly of the head housing <NUM> with the spool <NUM> and also facilitates the user to open the head housing <NUM> to detect a condition inside the head housing <NUM>.

As illustrated in <FIG>, from top to bottom in the direction of the first axis <NUM>, the grass cutting head <NUM> includes the head housing <NUM>, the spool <NUM>, and an operating member <NUM>. The head housing <NUM> is provided with one accommodation space. The spool <NUM> is installed in this accommodation space. The operating member <NUM> is connected to the head housing <NUM> through an intermediate member <NUM>. The driving shaft connected to the spool <NUM> to drive the spool <NUM> to rotate is disposed on the motor, and the driving shaft drives the grass cutting head <NUM> to rotate with the first axis <NUM> as an axis. That is, the spool <NUM> is connected to the driving apparatus <NUM> to introduce the power output by the driving apparatus <NUM> into the grass cutting head <NUM>. The operating member <NUM> is connected to the spool <NUM> and at least part of the operating member <NUM> protrudes to the outside of the head housing <NUM> for the user to operate. The grass cutting head <NUM> has a winding mode and a cutting mode. This winding mode is a manual winding mode. In the case where the grass cutting head <NUM> is in the manual winding mode, the user can rotate the operating member <NUM> so that the spool <NUM> rotates in a first rotation direction relative to the head housing <NUM> with the first axis <NUM> as the axis. In this case, the grass cutting line <NUM> can be wound to the spool <NUM>. In the case where the user activates the motor by operating the main switch, the motor drives the spool <NUM> to rotate in a second rotation direction with the first axis <NUM> as the axis so that the grass trimmer <NUM> is in the trimmer mode. In this embodiment, when viewed from the motor to the grass cutting 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 of course, it is not limited thereto. In other embodiments, the driving shaft on the motor may also be connected to the head housing <NUM>, and the operating member <NUM> may also rotate together with the head housing <NUM>. In this manner, the user rotates the operating member <NUM> to drive the head housing <NUM> to rotate so that there is a relative rotation between the spool <NUM> and the head housing <NUM>, and thus the grass cutting line <NUM> is wound around the spool <NUM>.

As illustrated in <FIG>, to facilitate the user to quickly insert the grass cutting line <NUM> into the grass cutting head <NUM> and be wound around the spool <NUM> without removing the grass cutting head <NUM>, this application provides a guiding component to guide the grass cutting line <NUM> to be wound around the spool <NUM>. The guiding component includes a first guiding structure <NUM> and a second guiding structure <NUM>. The first guiding structure <NUM> facilitates the user to quickly pass the grass cutting line <NUM> through the inside of the grass cutting head <NUM>, and guide the grass cutting line <NUM> to be wound around the spool <NUM> through the second guiding structure <NUM>.

In an embodiment, the first guiding structure <NUM> is a threading channel disposed on the head housing <NUM>, the second guiding structure <NUM> is disposed on the spool <NUM>, and the threading channel is located outside the spool <NUM>. In this manner, in the case where the spool <NUM> is installed inside grass cutting head <NUM>, the user may directly pass the grass cutting line <NUM> in the threading channel on the head housing <NUM> through one outer threading hole <NUM> on the head housing <NUM>, and pass it out of another outer threading hole <NUM>. In this case, guided by the threading channel, the grass cutting line <NUM> passes through the grass cutting head <NUM>, and then the spool <NUM> is rotated, the grass cutting line <NUM> is guided into the winding groove <NUM> of the spool <NUM> through the second guiding structure <NUM> on the spool <NUM>, and then the spool <NUM> is rotated until the entire grass cutting line <NUM> is wound around the spool <NUM> so that the storage of the grass cutting line <NUM> can be achieved.

As illustrated in <FIG>, the first housing <NUM> is provided with an opening 131c for threading, the second housing <NUM> is connected to the first housing <NUM>, and the second housing <NUM> rotates synchronously with the first housing <NUM>. After the first housing <NUM> and the second housing <NUM> are connected, the first housing <NUM> and the second housing <NUM> jointly form the preceding accommodation space around the first axis <NUM>. In this embodiment, the first housing <NUM> and the second housing <NUM> are connected by a snap so that a detachable connection is formed between the first housing <NUM> and the second housing <NUM>. As shown in <FIG> and <FIG>, the first housing <NUM> includes a first surface 131a and a second surface 131b. The first surface 131a is provided with or connected to a first airflow member 131d. The first airflow member 131d generates an airflow away from the grass cutting head <NUM> in the case where the first airflow member 131d rotates with the grass cutting head <NUM>. The first airflow member 131d is a fan blade formed on the first surface 131a of the first housing <NUM>. In the case where the fan blade rotates at a high speed, on the one hand, the fan blade can prevent grass clippings from being wound on the driving shaft of the motor, and on the other hand, the fan blade can perform heat dissipation. In an embodiment, the fan blade is also fixedly connected to or integrally formed with an anti-wrapping cover <NUM>. The anti-wrapping cover <NUM> can prevent grass clippings from entering the grass cutting head <NUM> and prevent the grass cutting head <NUM> from failing.

As illustrated in <FIG>, the second surface 131b of the first housing <NUM> is provided with or connected to the first guiding structure <NUM>. In this embodiment, the first guiding structure <NUM> and the first housing <NUM> are formed separately and fixedly connected by screws. In other embodiments, the connection manner of the first guiding structure <NUM> and the first housing <NUM> is not limited to the preceding connection manners, and other fixed connection or detachable connection manners such as snap connection or bonding may be used as long as the first guiding structure <NUM> is connected to the first housing <NUM> without relative displacement. Alternatively, the first guiding member <NUM> and the first housing <NUM> are integrally formed. In this embodiment, the front side, the rear side, the left side, and the right side are defined in <FIG>. As shown in <FIG>, in the case where the first guiding structure <NUM> and the first housing <NUM> are fixedly connected to form an entirety, a channel through which the grass cutting line <NUM> passes is formed in the front-and-rear direction. In the left-and-right direction, the first housing <NUM> is provided with a connecting portion configured to be connected to the second housing <NUM>. The first guiding structure <NUM> is provided with a notch <NUM>. The first housing <NUM> is provided with the opening 131c (refer to <FIG>). The notch <NUM> and the opening 131c correspond to each other and communicate with the outer threading hole <NUM> configured for allowing the grass cutting line <NUM> to pass in or out. The integral structure formed by the first housing <NUM> and the first guiding structure <NUM> forms a first through hole around the first axis <NUM>. The driving shaft is capable of passing through the first through hole. The first guiding structure <NUM> forms a threading channel around the first through hole.

In an embodiment, the plane where the threading channel is located is defined as a first plane, and the first plane is basically coplanar with the second surface 131b of the first housing <NUM>. As illustrated in <FIG>, on the first plane, the first guiding structure <NUM> is provided with multiple protrusions distributed around the first through hole. The multiple protrusions divide the first plane into three areas, which are a threading guiding area <NUM> through which the grass cutting line <NUM> passes, a temporary storage area <NUM> for the grass cutting line <NUM>, and a rotation area <NUM> in which the second guiding structure <NUM> rotates, respectively. The multiple protrusions include a first protrusion <NUM>, a second protrusion <NUM>, a third protrusion <NUM>, and a fourth protrusion <NUM>. The circumferential radius from the position of the first protrusion <NUM> to the position of the fourth protrusion <NUM> gradually increases, and the first protrusion <NUM>, the second protrusion <NUM>, the third protrusion <NUM>, and the fourth protrusion <NUM> are all ridges protruding from the first plane. The first protrusion <NUM> and the second protrusion <NUM> form the temporary storage area <NUM> for the grass cutting line <NUM>. The second protrusion <NUM> and the third protrusion <NUM> form the threading guiding area <NUM>. The third protrusion <NUM> and the fourth protrusion <NUM> form the r otation area <NUM>.

The first protrusion <NUM> is a continuous and smooth circle formed around the first through hole. The second protrusion <NUM> is a continuous and irregular circular arc or line segment formed around the first through hole. The second protrusion <NUM> includes one or more circular arcs or line segments, and a guiding portion <NUM> that guides the insertion of the grass cutting line <NUM> is formed at the notch <NUM>. The projection of the guiding portion <NUM> on the first plane is basically triangular. The guiding portion <NUM> protrudes from the circumference where the second protrusion <NUM> is located and is symmetrical with respect to the front-and-rear direction as shown in the figure. The guiding portion <NUM> and the second protrusion <NUM> are integrally formed. The guiding portion <NUM> is continuous and smooth, which facilitates the insertion of the grass cutting line <NUM>. In this embodiment, two guiding portions <NUM> are disposed symmetrically with respect to the left-and-right direction. Two guiding portions <NUM> divide the threading guiding area <NUM> into two sections, and the grass cutting line <NUM> is capable of passing through both sections. Alternatively, in other embodiments, one of the guiding sections may be closed and only one guiding section is opened for the grass cutting line <NUM> to pass through. The third protrusion <NUM> is a continuous but irregular circular arc formed around the first through hole and is broken at the notch <NUM> so that two arc segments symmetrical with respect to the front-and-rear direction are formed. The fourth protrusion <NUM> is a continuous circular arc formed around the first through hole and is broken at the notch <NUM> so that an opening for the grass cutting line <NUM> to pass out of or in is formed.

As illustrated in <FIG>, the spool <NUM> includes a main body <NUM> and a stopper formed around the main body <NUM>. The stopper includes a first stopping portion <NUM> and a second stopping portion <NUM>. The winding groove <NUM> is formed between the first stopping portion <NUM> and the second stopping portion <NUM>. The stopper is configured to prevent the grass cutting line <NUM> from detaching from the winding groove <NUM> in the direction of the first axis <NUM>. In a plane perpendicular to the direction of the first axis <NUM>, the projections of the first stopping portion <NUM> and the second stopping portion <NUM> basically overlap and form a ring around the main body <NUM>. The main body <NUM> includes a first section 121a and a second section 121b. The first section 121a is a hollow cylinder formed around the first axis <NUM>. The second section 121b is also a hollow cylinder formed around the first axis <NUM>. The outer diameter of the cylinder of the first section 121a is less than the outer diameter of the cylinder of the second section 121b. The first section 121a and the second section 121b are connected at a position close to the first stopping portion <NUM> and deviate from the position of the first stopping portion <NUM>. In an embodiment, the first stopping portion <NUM> is further provided with an accommodation groove <NUM> around the first section 121a of the main body <NUM>. The accommodation groove <NUM> is configured to accommodate the grass cutting line <NUM>. This accommodation groove <NUM> is a circular notch formed by the first section 121a of the main body <NUM> and the first stopping portion <NUM>. The projections of this accommodation groove <NUM> and the temporary storage area <NUM> in the direction perpendicular to the first axis <NUM> at least partially overlap. In this embodiment, the accommodation groove <NUM> and the temporary storage area <NUM> basically overlap, and the accommodation groove <NUM> and the temporary storage area <NUM> form an accommodation portion that accommodates at least part of the grass cutting line <NUM>. The first stopping portion <NUM> is further provided with the second guiding structure <NUM> that guides the grass cutting line <NUM> to be wound around the winding groove <NUM>. In an embodiment, the first stopping portion <NUM> is provided with two openings 122a symmetrical with respect to the first axis <NUM>. These openings 122a are basically polygonal and communicate with the accommodation groove <NUM>. A fulcrum portion that guides the grass cutting line <NUM> to be wound around the winding groove <NUM> is formed at the junction of the accommodation groove <NUM> and the openings 122a. The fulcrum portion is configured to apply a reverse force to the grass cutting line <NUM> to prevent the following situation: in the case where the user performs winding, the direction of the force is basically the same as the direction of the grass cutting line <NUM> so that winding fails. The second guiding structure <NUM> is disposed on the first stopping portion <NUM> and located at the openings 122a. The structure that is formed at the openings 122a, protrudes from the plane of the first stopping portion <NUM> and is farther from the first stopping portion <NUM> is the second guiding structure <NUM>. As shown in <FIG>, the second guiding structure <NUM> is a protrusion upward tilted from the stopper and is provided with a guiding surface 125a. This guiding surface 125a is smooth and continuous and integrally formed with the first stopping portion <NUM>. Alternatively, in the case where the strength of the spool <NUM> is insufficient, the second guiding structure <NUM> may also be an independent element that satisfies the strength requirement and is fixedly connected to the first stopping portion <NUM>. Moreover, to prevent the grass cutting line <NUM> from slipping out from the upper end of the second guiding structure <NUM>, the notch between the second guiding structure <NUM> and the head housing <NUM> is configured to be less than the diameter of the grass cutting line <NUM>. In this manner, the grass cutting line <NUM> may only slide into the accommodation groove <NUM> from the openings 122a. In an embodiment, two second guiding structures <NUM> are disposed, and the two second guiding structures <NUM> are respectively located at the two openings 122a of the first stopping portion <NUM>.

To match with the grass cutting line <NUM> to be smoothly inserted into the threading channel of the first guiding structure <NUM>, the eyelet member <NUM> as shown in <FIG> is further provided. This eyelet member <NUM> includes a third surface and a fourth surface. The third surface of the eyelet member <NUM> includes a threading hole <NUM>. The threading hole <NUM> is specifically waist-shaped and extends in a straight line parallel to the first axis <NUM>. As shown in <FIG>, the fourth surface of the eyelet member <NUM> is provided with a guiding surface <NUM>. The opening of the guiding surface <NUM> gradually expands and the sidewall of the guiding surface <NUM> is continuous and smooth. The third surface is communicated with the fourth surface through the threading hole <NUM>. Two eyelet members <NUM> are provided. The two eyelet members <NUM> are respectively installed on the outer threading hole <NUM> of the head housing <NUM>. The grass cutting line <NUM> is inserted into one of the eyelet members <NUM> and out of the other one of the eyelet members <NUM>. The guiding surface <NUM> on the threading hole <NUM> of the eyelet members <NUM> can facilitate the passing-out of the grass cutting line <NUM>. In an embodiment, in the threading mode, the threading hole <NUM> of these eyelet members19 can achieve the passing-in of the grass cutting line <NUM> and the passing-out of the grass cutting line <NUM>.

As illustrated in <FIG> and <FIG>, the operating member <NUM> rotates synchronously with the spool <NUM>. The spool <NUM> is fixed in a position in the direction of the first axis <NUM> relative to the first housing <NUM>. The operating member <NUM> is slidably connected to the spool <NUM> in the direction of the first axis <NUM> or a direction parallel to the first axis <NUM>. The operating member <NUM> is at least partially located outside of the head housing <NUM>. The head housing <NUM> is further provided with a second through hole that allows the operating member <NUM> to partially extend into the accommodation space in the direction of the first axis <NUM> from the outside of the accommodation space. The second through hole may be formed by the second housing <NUM>. The operating member <NUM> may also close at least part of the second through hole. As shown in <FIG>, the portion of the operating member <NUM> located outside of the head housing <NUM> is provided with an operating portion <NUM> for the user to operate. In the case where the user rotates the operating portion <NUM>, the operating member <NUM> drives the spool <NUM> to rotate together with the operating member <NUM>. The operating portion <NUM> rotates around the second housing <NUM> with the first axis <NUM> as the axis. A notch is further formed between the operating portion <NUM> and the second housing <NUM> to communicate the interior and exterior of the accommodation space. In this manner, abrasion between the operating portion <NUM> and the second housing <NUM> can be avoided, and a movement stroke of the operating portion <NUM> sliding in the direction of the first axis <NUM> can be provided. In an embodiment, to prevent dust from entering the notch, a dust-proof structure may also be disposed at this notch.

In this embodiment, the operating portion <NUM> surrounds at least part of the head housing <NUM> in the circumference around the first axis <NUM> so that the head housing <NUM> is at least partially located in the space surrounded by the operating portion <NUM>. In this manner, the diameter of the operating portion <NUM> is relatively large, and thus the user can rotate the operating member <NUM> more comfortably. To enable the motor to drive the grass cutting head <NUM> to rotate in the second rotation direction with the first axis <NUM> as the axis to achieve the trimming function, as shown in <FIG> and <FIG>, the grass cutting head <NUM> further includes an intermediate member <NUM> for achieving dynamic torque transmission between the spool <NUM> and the head housing <NUM>. The intermediate member <NUM> rotates synchronously with the spool <NUM>, and the intermediate member <NUM> is slidably connected to the spool <NUM> in the direction of the first axis <NUM>. In this embodiment, the intermediate member <NUM> is fixedly connected to the operating member <NUM> by screws. The entirety formed by the intermediate member <NUM> and the operating member <NUM> rotates synchronously with the spool <NUM>, and this entirety slides relative to the spool <NUM> in the direction of the first axis <NUM>. In other embodiments, the intermediate member <NUM> may also be integrally formed with the operating member <NUM>. In an embodiment, the number of parts for achieving torque transmission between the spool <NUM> and the head housing <NUM> is not limited to one, but may be more than one. In this case, the intermediate member <NUM> may be understood as one of the parts.

As illustrated in <FIG>, the intermediate member <NUM> is provided with a driving portion <NUM>, and the head housing <NUM> is provided with a matching portion 132a that matches with the driving portion <NUM>. In an embodiment, the matching portion 132a is provided with a driving surface 132b and a spanning surface 132c. In the case where the driving portion <NUM> is located in a position in contact with the driving surface 132b of the matching portion 132a, the driving surface 132b prevents the spool <NUM> from rotating in the second rotation direction relative to the head housing <NUM> to receive the driving force of the driving portion <NUM>. In this case, in the condition where the motor drives the spool <NUM> to rotate in the second rotation direction with the first axis <NUM> as the axis, the driving portion <NUM> matches with the driving surface 132b so that the head housing <NUM> rotates along with the spool <NUM> in the second rotation direction with the first axis <NUM> as the axis, and thus the trimming function can be achieved. In the case where the user rotates the operating member <NUM> in the first rotation direction with the first axis <NUM> as the axis, the spanning surface 132c of the matching portion 132a allows the driving portion <NUM> to slide along the spanning surface 132c. In this case, the entirety formed by the intermediate member <NUM>, the operating member <NUM>, and the spool <NUM> rotates in the first rotation direction relative to the head housing <NUM> with the first axis <NUM> as the axis so that the grass cutting line <NUM> is wound around the spool <NUM>, and thus the winding function can be achieved. In this embodiment, in the case where the winding is needed, the user needs to hold the head housing <NUM> with one hand and rotate the operating member <NUM> in the first rotation direction with the first axis <NUM> as the axis with the other hand. In this case, the spanning surface 132c allows the spool <NUM> to rotate relative to the head housing <NUM> with the first axis <NUM> as the axis. In other embodiments, the grass cutting head <NUM> may further be provided with a restricting apparatus that restricts the rotation of the head housing <NUM> so that the user does not need to hold the head housing <NUM> with one hand and rotate the operating member <NUM> with the other hand to perform the winding function. In this manner, as long as the user fixes the position of the grass trimmer <NUM> and rotates the operating member <NUM> with one hand, the grass cutting line <NUM> is wound around the spool <NUM>. Therefore, the following problem can be avoided: the grass cutting line <NUM> is wound around the arm. In other embodiments, in the case where the head housing <NUM> is connected to the motor and the driving force output by the motor may be introduced into the grass cutting head <NUM>, the operating member <NUM> and the intermediate member <NUM> may both rotate together with the head housing <NUM>, and the intermediate member <NUM> is further slidably connected to the head housing <NUM>. Through the power transmission performed by the intermediate member <NUM>, the spool <NUM> rotates with the head housing <NUM> so that the trimming function can be achieved.

The operating member <NUM> may also slide to a first position and a second position when sliding in the direction of the first axis <NUM> relative to the spool <NUM>. In the case where the operating member <NUM> slides to the first position, the intermediate member <NUM> also slides in the direction of the first axis <NUM> to a driving position along with the operating member <NUM>. In this case, the driving portion <NUM> matches with the matching portion 132a. In this case, in the condition where the motor drives the spool <NUM> to rotate in the second rotation direction with the first axis <NUM> as the axis, and driven by the driving portion <NUM>, the head housing <NUM> rotates with the spool <NUM> so that the grass cutting head <NUM> is in the cutting mode in this case. In the case where the grass trimmer <NUM> is in the process of trimming, in the condition where the user makes the grass cutting head <NUM> hit the ground in this case, the ground applies a reverse force to the operating member <NUM> so that the operating member <NUM> slides to the second position in the direction of the first axis <NUM>, and the intermediate member <NUM> also slides along the first axis <NUM> to a non-driving position along with the operating member <NUM>. In this case, the driving portion <NUM> is disengaged from the matching portion 132a so that the spool <NUM> rotates in the second rotation direction relative to the head housing <NUM>, and thus the grass cutting head <NUM> is in a pay-off mode, and the length of the grass cutting line <NUM> extending from the head housing <NUM> increases.

As illustrated in <FIG> and <FIG>, the grass cutting head <NUM> further includes a biasing element <NUM> that is arranged in a biased manner between the spool <NUM> and the operating member <NUM> to bias the operating member <NUM> to move toward the first position. The biasing element <NUM> may be a coil spring. The spanning surface 132c of the matching portion 132a slidably matches with the driving portion <NUM> so that the spanning surface 132c allows the entirety formed by the intermediate member <NUM> and the operating member <NUM> to slide along the spanning surface 132c relative to the matching portion 132a.

The operating element <NUM> is further connected to a contact <NUM>, and the contact <NUM> is connected to the operating portion <NUM> of the operating element <NUM>. The contact <NUM> is located outside of the accommodation space, and the contact <NUM> includes a contact surface in contact with the ground in the case where the grass cutting head <NUM> is trimming. The contact <NUM> is rotatably connected to the operating member <NUM> with the first axis <NUM> as the axis. In this manner, in the case where the grass cutting head <NUM> is trimming, the grass cutting head <NUM> rotates at a high speed with the first axis <NUM> as the axis. The grass cutting head <NUM> rotates at a relatively high speed. The contact <NUM> is in contact with the ground so that the abrasion of the grass cutting head <NUM> can be effectively prevented and the service life of the grass cutting head <NUM> can be improved. The contact <NUM> is rotatably connected to the operating member <NUM> through a connecting member. In this embodiment, this connecting member is a one-way bearing <NUM>. The one-way bearing <NUM> enables the contact <NUM> to rotate in the first rotation direction relative to the operating member <NUM> with the first axis <NUM> as the axis and prevents the contact <NUM> from rotating in the second rotation direction relative to the operating member <NUM> with the first axis <NUM> as the axis. The entirety formed by the operating member <NUM> and the contact <NUM> is capable of closing the second through hole formed by the second housing <NUM>.

In the case where the user needs to perform the winding, the user passes the grass cutting line <NUM> in the upper side of the threading hole <NUM> of one eyelet member <NUM> and out of another eyelet member <NUM> guided by the first guiding structure <NUM> and places the grass cutting line <NUM> in the upper position of the threading hole <NUM>. During this period, the spool <NUM> is at an arbitrary position relative to the head housing <NUM>. The user does not need to perform any alignment operations between the head housing <NUM> and the spool <NUM>, which greatly improves the operating convenience of the user. In this case, the user operates the operating portion <NUM> of the grass cutting head <NUM> to rotate in the first direction, the operating member <NUM> drives the spool <NUM> to rotate together with the operating member <NUM> in the direction of the first axis <NUM>, and the second guiding structure <NUM> on the spool <NUM> is located in the rotation area <NUM> of the first guiding structure <NUM> in this case. In the case where the second guiding structure <NUM> rotates to the notch <NUM> of the first guiding structure <NUM>, the grass cutting line <NUM> is pushed by the guiding surface 125a of the second guiding structure <NUM>, enters the temporary storage area <NUM> from the guiding area <NUM> of the first guiding structure <NUM>, at least partially slides along the guiding surface 125a of the second guiding structure <NUM> into the accommodation groove <NUM> of the spool <NUM>, and enters the winding groove <NUM> at the same time. In this case, the part where the grass cutting line <NUM> passes through the threading hole <NUM> moves downward along the hole wall of the threading hole <NUM>. In an embodiment, the position of the grass cutting line <NUM> in the eyelet member <NUM> slides from the upper position of the threading hole <NUM> to the lower position of the threading hole <NUM>. The grass cutting line <NUM> is at least partially restricted in the accommodation groove <NUM> of the spool <NUM>. Moreover, under the action of the fulcrum portion, in the case where the spool <NUM> rotates in the first rotation direction, a force facing away from the first rotation direction is applied to the grass cutting line <NUM> so that the grass cutting line <NUM> is wound around the winding groove <NUM>, and then the operating member <NUM> is rotated in the first rotation direction, thereby driving the spool <NUM> to continue winding until the winding is completed. During the winding process, due to fatigue or the operation, the user operates discontinuously when operating the operating member <NUM> to rotate. Since the driving portion <NUM> matches with the driving surface 132b, the spool <NUM> and the head housing <NUM> are prevented from rotating in the second rotation direction. Therefore, while the grass cutting line <NUM> has rigidity, the grass cutting line <NUM> does not automatically rotate and leave in the second rotation direction.

After completing the winding, the user may operate the operating apparatus <NUM> to control the grass trimmer <NUM> to start trimming. Moreover, in the case where the grass cutting line <NUM> is worn to a preset condition, the contact <NUM> is hit. In this case, the operating member <NUM> and the spool <NUM> may slide from the first position to the second position in the direction of the first axis <NUM>. The spool <NUM> achieves the pay-off under the action of a centrifugal force. In the case where the grass cutting line <NUM> is released to a preset length, trimming may be continued.

The first guiding structure <NUM> is provided to guide the grass cutting line <NUM> through the head housing <NUM>, and the second guiding structure <NUM> is provided to guide the grass cutting line <NUM> into the spool <NUM> to be wound. In this manner, the user does not need to align the relative positions of the spool <NUM> and the head housing <NUM> to perform the threading and winding, and thus the work efficiency and operating experience of the user can be improved.

In an embodiment, the first guiding structure may also be connected to other positions of the head housing. <FIG> and <FIG> show the structure of the grass cutting head in second embodiment. In this embodiment, the grass cutting head has the same driving apparatus and operating apparatus as in first embodiment, and only the structures in this embodiment different from first embodiment will be described below.

The upper side and the lower side are defined in <FIG>. In this embodiment, the third guiding member <NUM> is connected to the second housing <NUM> by a fixing member and is located between the spool <NUM> and the intermediate member <NUM>. The structure of the third guiding member <NUM> is the same as the structure of the first guiding structure <NUM> in first embodiment, except that the positions and orientations are different. The fourth guiding member <NUM> is located on the second stopping portion of the spool <NUM>. The structure of the fourth guiding member <NUM> is the same as the structure of the second guiding structure <NUM> in first embodiment, except that the positions are different. To match with the passing-through of the grass cutting line, as shown in <FIG>, the head housing is further provided with two head housing eyelet members <NUM>. The head housing eyelet member <NUM> is provided with a first threading hole <NUM> and a second threading hole <NUM>. The first threading hole <NUM> is located at the lower position of the head housing eyelet member <NUM> shown in the figure, and the second threading hole <NUM> is located at the upper position of the head housing eyelet member <NUM> shown in the figure. The grass cutting line passes in the threading channel of the third guiding member <NUM> from the first threading hole <NUM> on the lower side of the figure and out of the first threading hole <NUM> of another head housing eyelet member <NUM> so that the operating member rotates in the first rotation direction, the grass cutting line at least partially rotates into the accommodation groove <NUM> of the spool <NUM> under the action of the fourth guiding member <NUM>, and then the operating member is rotated, thereby achieving the winding by the same principle as in first embodiment until the winding is completed.

In an embodiment, the grass trimmer has the same driving apparatus and operating apparatus as in first embodiment, and only the structures in this embodiment different from first embodiment will be described below. <FIG> show the grass cutting head <NUM> of the grass trimmer in third embodiment. In this embodiment, the head housing includes a first housing portion <NUM> and a second housing portion <NUM>. The first guiding structure <NUM> is disposed on the second housing portion <NUM>, and the second housing portion <NUM> is specifically an end farther from the driving apparatus. The second guiding structure <NUM> is disposed on the spool <NUM> and is disposed on a side closer to the first guiding structure <NUM>. The first guiding structure <NUM> is fixedly connected to or integrally formed with the second housing portion <NUM>. The first guiding structure <NUM> is provided with the same guiding area 521a through which the grass cutting line passes, the same temporary storage area 521b for the grass cutting line, and the same rotation area 521c in which the second guiding structure <NUM> rotates as in first embodiment. In this embodiment, the guiding area 521a is actually an arc-shaped area distributed around the first axis <NUM>. As an optional embodiment, the guiding area 521a may also be a linear area intersecting with the first axis <NUM> or close to the first axis <NUM>.

As illustrated in <FIG>, the second housing portion <NUM> further includes an eyelet member <NUM> configured for allowing the grass cutting line to pass in or out. The eyelet member <NUM> includes one outer threading hole 522a extending around the circumference of the first axis <NUM>. The eyelet member <NUM> is specifically a waist-shaped hole. The eyelet member <NUM> includes a first surface and a second surface. The first surface and the second surface communicate with each other and form the outer threading hole 522a. The first surface is provided with a first guiding surface 522b for the grass cutting line to pass in or out, and the first guiding surface 522b is smooth and continuous. The second surface is provided with a second guiding surface 522c for the grass cutting line to pass in or out, and the second guiding surface 522c is smooth and continuous. In the case where the outermost edge of the first guiding surface 522b is connected to the innermost edge of the second guiding surface 522c farther from the first guiding surface 522b, connecting lines L1 and L2 are provided around the circumference of the first axis <NUM>, and a preset included angle A is formed between L1 and L2. In this embodiment, the length of the outer threading hole 522a on the eyelet member <NUM> in a direction perpendicular to the first axis <NUM> is greater than the length of the outer threading hole 522a in the direction of the first axis <NUM>. Therefore, when threading the grass cutting line, the grass cutting line is allowed to have a relatively large range of movement around the circumference of the first axis <NUM> so that the grass cutting line adapts to the first guiding structure <NUM>. The height of the outer threading hole 522a of the eyelet member <NUM> in the direction of the first axis <NUM> is basically the same as the height of the guiding area 521a of the first guiding structure <NUM> in the direction of the first axis <NUM>. That is, there is basically no height difference between the height of the outer threading hole 522a of the eyelet member <NUM> in the direction of the first axis <NUM> and the height of the guiding area 521a of the first guiding structure <NUM> in the direction of the first axis <NUM>. Therefore, the following problem can be avoided: the grass cutting line is misaligned when passing through one of the eyelet members <NUM> into the guiding area 521a and out of another eyelet member <NUM>, and thus the grass cutting line cannot quickly pass out. In fact, the length of the outer threading hole 522a distributed in a direction perpendicular to the first axis <NUM> is relatively large. Therefore, in the case where the grass cutting line passes in the eyelet member <NUM>, the grass cutting line may have a relatively large range to adapt to the bending of the guiding area 521a. In this manner, the bending amount of the grass cutting line is reduced, and the following problem can be avoided: in the case where the grass cutting line passes out of another eyelet member <NUM>, due to the large deformation amount, the grass cutting line deviates from the outer threading hole 522a of the eyelet member <NUM> and thus fails to pass through. On the other hand, in the case where the grass cutting line passes out of the eyelet member <NUM> from the other end, due to the relatively large circumferential space, the probability of the grass cutting line deviating from the outer threading hole 522a can be reduced. In fact, under the action of the guiding area 521a of the first guiding structure <NUM>, the range for the grass cutting line to pass in or out is limited to the included angle A formed by the two connecting lines L1 and L2 of the outer threading hole 522a. Moreover, the two guiding surfaces of the outer threading hole 522a also effectively guide the grass cutting line to pass in the guiding area 521a of the first guiding structure <NUM> and prevent the grass cutting line from deviating from the guiding area 521a and entering the rotation area 521c.

In this embodiment, a damping apparatus is further provided for the relative rotation between the head housing and the spool <NUM>. At the same time, a control switch is further provided for controlling the activation of the damping apparatus. The damping apparatus may specifically be a stop pin (not shown in the figure) that produces a damping effect on the head housing. The damping apparatus may also be a one-way bearing <NUM> and a rotation support <NUM> that matches with the one-way bearing <NUM>. The one-way bearing <NUM> makes two parts or parts connected to the one-way bearing <NUM> rotate relative to one another in one rotation direction and not rotate relative to one other in another rotation direction. The rotation support <NUM> is rotatably connected to a part of the grass cutting head <NUM> and supports the rotation of the grass cutting head <NUM>. The rotation support <NUM> may be the first housing that accommodates the motor in the grass trimmer, or may be other parts fixedly connected to the first housing such as a grass trimmer guard.

More specifically, the one-way bearing <NUM> is disposed between the rotation support <NUM> and the first housing portion <NUM> so that the rotation support <NUM> and the first housing portion <NUM> form a one-way rotation connection. That is, in the case where the rotation support <NUM> is used as a reference, the first housing portion <NUM> can rotate in one rotation direction but cannot rotate in another rotation direction.

The driving shaft is connected to the spool <NUM> in a non-rotational manner so that the spool <NUM> rotates in both directions relative to the rotation support <NUM>. In the case where the rotation support <NUM> is used as a reference, the spool <NUM> can rotate forward or backward.

Similar to the foregoing, the spool <NUM> is provided with a first circumferential transmission structure, and the first housing portion <NUM> is provided with a second circumferential transmission structure that matches with the first circumferential transmission structure. The difference is that at least one of the transmission surfaces of the first circumferential transmission structure and the second circumferential transmission structure that can achieve transmission is parallel to the axis, which makes the first circumferential transmission structure unable to disengage from the second circumferential transmission structure in the case where the first circumferential transmission structure and the second circumferential transmission structure rotate in a certain rotation direction.

Based on the preceding hardware, in the case where the motor (not shown in the figure) rotates forward, the driving shaft drives the spool <NUM> to rotate forward. In this case, the first circumferential transmission structure and the second circumferential transmission structure achieve torque transmission through the transmission surface parallel to the axis. At the same time, the one-way bearing <NUM> is provided so that the first housing portion <NUM> can rotate forward relative to the rotation support <NUM> (that is, relative to the entire grass trimmer). Therefore, in this case, the spool <NUM> and the first housing portion <NUM> rotate synchronously, and the grass trimmer may execute the cutting mode. In the case where the motor rotates backward, the driving shaft drives the spool <NUM> to rotate backward. Since the one-way bearing <NUM> prevents the first housing portion <NUM> from rotating backward, the first housing portion <NUM> makes the spool <NUM> rotates relative to the first housing portion <NUM>. In this case, since the contact surface between the first circumferential transmission structure and the second circumferential transmission structure is a ramp, the first circumferential transmission structure is disengaged from the second circumferential transmission structure. The first circumferential transmission structure and the second circumferential transmission structure cannot completely hinder the relative movement between the spool <NUM> and the first housing portion <NUM>. Therefore, in this case, the spool <NUM> rotates relative to the first housing portion <NUM> continuously so that the grass trimmer may execute an automatic winding mode.

Claim 1:
A grass cutting head (<NUM>, <NUM>), comprising:
a spool (<NUM>, <NUM>, <NUM>) configured for winding a grass cutting line (<NUM>);
a head housing (<NUM>) configured to accommodate at least part of the spool; the grass cutting head characterized by comprising:
a first guiding structure (<NUM>, <NUM>) configured to guide the grass cutting line through an inside of the grass cutting head when threading the grass cutting line without removing the grass cutting head; and
a second guiding structure (<NUM>, <NUM>), formed on the spool or connected to the spool, the second guiding structure being configured to guide the grass cutting line to move and be wound around the spool when a relative rotation occurs between the spool and the head housing.