Patent Publication Number: US-2023157206-A1

Title: Trimmer head and trimmer thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application relies on and claims priority to the following applications: Chinese Patent Application No. CN2021229092651, filed on Nov. 19, 2021 (published as CN217116927U), and Chinese Patent Application No. CN2021228569659, filed on Nov. 19, 2021 (published as CN217509420U), the entire contents of both of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The embodiments of the disclosure refer generally to garden tools, and more specifically to a trimmer head and a trimmer thereof. 
     BACKGROUND 
     There are not many kinds of trimmer heads on the market with interchangeable string and blades. One of the main reasons is that the prior art needs to make a big change in the structure when designing two different kinds of trimming assembly of string and blades to one trimmer head. Especially for the string trimmer, the connection position of the trimming line is raised from the middle of the lower cover to the upper edge of the lower cover. In this way the distance between the trimming line and the lawn ground increases, which reduces the trimming efficiency and makes it more difficult to control the flatness of the lawn. 
     On the other hand, in prior arts for the blade trimmer, the blade is mounted on the lower housing through the plug-in connector. In the actual trimming operation, when the blade encounters a hard object, the force on the blade is directly transferred to the lower housing. It is difficult to separately strengthen the stressed position of the lower housing as molded in one piece and easy to damage. Therefore, the whole lower housing needs to be replaced when damaged. 
     SUMMARY 
     As will be disclosed in detail in the description, the inventors have realized that the traditional trimmer head brings about at least two problems. It is therefore an object of the teachings of this application to overcome or at least reduce those problems. 
     According to one aspect there is provided a trimmer head which enables for a high-efficient trimming comprising an upper cover assembly being connected to and driven by a motor, wherein the upper cover assembly is configured to be removably connected to a first trimming assembly or a second trimming assembly selectively, and is provided with at least one connection hole in its side wall; the first trimming assembly is configured to include a first lower cover, a first cutting member and a first base; the second trimming assembly is configured to include a second lower cover, a second cutting member and a second base; wherein the first base is at least partially inserted into the connection hole when the first trimming assembly is mounted, and the second lower cover is at least partially inserted into the connection hole when the second trimming assembly is mounted. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The embodiments of the disclosure will be described in further detail under reference to the accompanying drawings in which: 
         FIG.  1    is a perspective view of the trimmer head of an embodiment of the disclosure with the first trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  2    is a perspective view of the trimmer head of an embodiment of the disclosure with the second trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  3    is a exploded perspective view of the trimmer head of an embodiment of the disclosure with the first trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  4    is a exploded perspective view of the trimmer head of an embodiment of the disclosure with the second trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  5    is a cross-sectional view of the trimmer head of an embodiment of the disclosure with the first trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  6    is a cross-sectional view of the trimmer head of an embodiment of the disclosure with the second trimming assembly mounted, with the side facing upward in the figure facing downward during operation. 
         FIG.  7    is a perspective view of the upper cover of an embodiment of the disclosure when it is assembled with the first base. 
         FIG.  8    is a perspective view of the mounting status of the holder into the upper cover and the first base of an embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following description is made for the purpose of illustrating the general principles of the present trimmer head and trimmer, and is not meant to limit the inventive concepts claimed in this document. Further, particular features described in this document can be used in combination with other described features in each of the various possible combinations and permutations. 
     Unless otherwise specifically defined in this document, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc. 
     It must also be noted that, as used in the specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents unless otherwise specified. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. All publications mentioned in this document are incorporated by reference. Nothing in this document is to be construed as an admission that the embodiments described in this document are not entitled to antedate such disclosure by virtue of prior invention. As used herein, the term “comprising” means “including, but not limited to”. Additionally, use the term “couple”, “coupled”, or “coupled to” may imply that two or more elements may be directly connected or may be indirectly coupled through one or more intervening elements. 
     In this document, position-identifying terms such as “vertical”, “horizontal”, “front”, “rear”, “top”, and “bottom” are not intended to limit the invention to a particular direction or orientation, but instead are only intended to denote relative positions, or positions corresponding to directions shown when a structure or product is oriented as shown in the Figures. 
     Referring to  FIGS.  1 ,  3 ,  5 ,  7  and  8   , an embodiment shows a trimmer head comprising an upper cover assembly  001  being connected to and driven by a motor, wherein the upper cover assembly  001  is configured to be removably connected to a first trimming assembly  100  or a second trimming assembly  200  selectively, and is provided with at least one connection hole  003  in its side wall. In this embodiment, a connection hole  003  is symmetrically provided on both walls of the upper cover assembly  001  along the bottom center line. 
     The first trimming assembly  100  is configured to include a first lower cover  01 , a first cutting member and a first base  111 . In this embodiment, the first base  111  is fixedly connected to the upper cover assembly  001  when the first trimming assembly  100  is mounted. The first base  111  is configured to include a first fixing part  12  that is at least partially inserted into the connection hole  003  when the first trimming assembly  100  is mounted. 
     Referring to  FIGS.  3  and  5   , the first lower cover  01  is removably assembled with the upper cover assembly  001  by a fastener  005  when the first trimming assembly  100  is mounted in the upper cover assembly  001 . In this embodiment, the fastener  005  is configured as a bolt. The upper cover assembly  001  has a raised pillar  101  in the bottom center and the pillar  101  is provided with a threaded hole  102  in the center. The first base  111  is set on the outer surface of the pillar  101 , and the first lower cover  01  is mounted at the threaded hole  102  by the bolt. 
     Referring to  FIG.  3   , the first cutting member and the first base  111  are clamped to the first lower cover  01  by the upper cover assembly  001 . The first base  111  is configured to be made of a hard material with a certain elasticity and is further configured as an oblong plate with a round projection in the center, and the projection is provided with a first connection part  118  adapted to the outer surface of the pillar  101 . Each end of the first base  111  is provided with a first extension part  119  with the same cross-section as the connection hole  003  and facing the same side of the plate. In this embodiment, the extending direction of the first extension part  119  is generally perpendicular to the extending direction of the first base  111 . The plate surface opposite the round projection is provided with a second connection part  117  provided symmetrically about the first connection part  118 . In this embodiment, the first connection part  118  is configured as a hole adapted to the pillar  101 , and the second connection part  117  is configured to include at least one projection. Both of the first extension parts  119  corresponding to the connection holes  003  are extruded inward from the opening side of the upper cover assembly  001 . A first fixing part  12  is provided on the outer side of the end of the first extension part  119  to make it easy to mount at the initial stage. By extruding the first base  111 , the first fixing part  12  is conflict with the inner wall around the corresponding connection hole  003 . By continuing to apply the extrusion force, the first base  111  produces elastic deformation. Referring to  FIG.  7   , the conflict between the two disappears until the first base  111  is pushed into the connection hole  003 , then the first base  111  returns to the initial state. A clearance  115  used to mount the first cutting member is on the side of the connection hole  003  towards the second connection part  117  when mounted. 
     The first cutting member includes a holder  112  and a blade  114 . The holder  112  is configured to be removably connected to the first base  111 . In this embodiment, the blade  114  is configured to be movably connected to the holder  112  by a connector  113 . In other embodiments, the blade  114  may also be configured to be integrally formed with the holder  112 . One end of the holder  112  passes through the connection hole  003  into the upper cover assembly  001  and is connected to the first base, and the other end of the holder  112  is mounted with a blade  114 . The holder  112  is configured as an oblong plate with a width the same as or slightly smaller than the connection hole  003 . One end of the plate surface is provided with a third connection part  116  adapted to the second connection part  117 , and the other end of the plate surface is thickened and is provided with a fourth connection part  120  with the connector  113 . The end of the third connection part  116  of the holder  112  passes through the clearance  115  and the third connection part  116  is connected to the second connection part  117 . The other end of the holder  112  is exposed outside the upper cover assembly  001 . The bottom of the first lower cover  01  is pressed against the holder  112 , so that the upper and lower positions of the holder  112  are limited. At the same time, the position of the holder  112  on both sides has been limited by the connection hole  003  in the upper cover assembly  001 , so the position of the holder  112  is completely limited, so that the blade  114  on the holder  112  can be positioned by the connector  113 . In this embodiment, the first trimming assembly  100  includes two blades  114 . In other embodiments, the number of blades can also be one, three, four, etc., just by changing the number of the corresponding connection holes  003  and making corresponding adjustments to the number and the structure of the adapting parts in the holder assembly  110 . In this embodiment, the second connection part  117  is configured as a projection and the third connection part  116  is configured as a hole adapted to the projection. In other embodiments, the third connection part  116  is configured as a projection and the second connection part  117  is configured as a hole adapted to the projection. 
     Referring to  FIG.  7   , when mounting the first trimming assembly  100 , firstly to place the opening of the upper cover  001  upward, and then to place the first base  111  into the upper cover  001  with the first connection part  118  corresponding to the pillar  101 , and the first base  111  is pressed to touch the bottom of the upper cover  001 . At this time, the two first extension parts  119  are inserted into the corresponding connection holes  003 . Then the holder  112  passes through the clearance  115  from the outside and is inserted by the second connection part  117  referring to  FIG.  8   . The thickened end of the plate surface of the holder  112  is exposed to the outer wall of the upper cover  001 . The first lower cover  01  is connected to the upper cover  001  by the fastener  005 . After the connection, at least one rib of the first upper cover  01  presses against the holder  112 , and the first base  111  and the holder  112  are pressed together at the bottom of the upper cover assembly  001 . The holder  112  has been limited to both sides by a connection hole before, so the position of the holder  112  is completely limited by pressing. Finally, the blade  114  is mounted on the holder  112  through the connector  113 , and all connections are completed since then. In some embodiments, the blade  114  and the holder  112  may be pre-mounted together. In other embodiments, the holder  112 , the connector  113 , and the blade  114  may be sold and used as an assembly. 
     Referring to  FIGS.  2 ,  4  and  6   , a trimming head is disclosed and includes an upper cover assembly  001  and a second trimming assembly. The second trimming assembly  200  is configured to include a second lower cover  02 , a second cutting member, and a second base  210 . In this embodiment, the second base  210  is movably connected to the upper cover assembly  001  when the second trimming assembly  200  is mounted. The second lower cover  02  includes a second fixing part which is at least partially inserted into the connection hole  003  when the second trimming assembly  200  is mounted. The connection hole  003  provides space for the second fixing part  22  in the second lower cover  02  to engage when the second trimming assembly  200  is used. 
     Referring to  FIG.  4   , the second lower cover  02  is configured to include at least one second extension part  021  being configured to be generally perpendicular to the second lower cover  02 ; the second fixing part  22  is configured to be provided on the outside of the end of the second extension part  021  away from the second lower cover  02 . The second fixing part  22  is inserted into the connection hole  003  to engage when the second lower cover  02  is assembled with the upper cover assembly  001 . In this embodiment, two second extension parts  021  are provided on the second lower cover  02  symmetrically about the center axis of rotation. 
     The second trimming assembly  200  is provided with at least one trimming line  211 . In this embodiment, the trimming line is wound on a wire reel with at least one end extending from the wire reel and extending out of the upper cover assembly  001 . Further, in this embodiment, the both ends of the trimming line extend from the wire reel and extend out of the upper cover assembly  001 . The side wall of the upper cover assembly  001  is provided with an opening  002  for the trimming line  211  to pass through. The opening  002  is used to limit the position of the trimming line  211 . Referring to  FIG.  4   , the second base  210  is configured to include a wire reel, and the second lower cover  02  is covered outside the second base  210 , which surrounds the second base  210  as a whole. 
     Further, two longitudinal ribs  006  are provided along the inner side wall on both sides of the connection hole  003  to strengthen the connection hole  003 , and also to guide the first base  111  or the second lower cover  02  when mounting. 
     The first lower cover  01 , the first base  111 , the holder  112 , the connector  113  and the blade  114  involved in the first trimming assembly  100  are removed in the opposite order of mounting when replacing the first trimming assembly  100  with the second trimming assembly  200 ; in some embodiments, the holder  112 , the connector  113  and the blade  114  are used as an assembly which can be removed as a whole. Then, the second base  210  is mounted into the upper cover assembly  001 , and then the second fixing part  22  on the second lower cover  02  is pressed downward against the position of the connection hole  003 . The two longitudinal ribs provided on both sides of the connection hole  003  are used to guide the second fixing part  22 . The second lower cover  02  is provided with elastic material, which makes the second fixing part  22  have better elastic restoration ability. The second fixing part  22  is deformed by pressure and bends or shrinks inward when the second fixing part  22  enters the inner wall of the second lower cover  02 . The second fixing part  22  is inserted into the connection hole  003  and returns to its original statues, and then the mounting is completed. 
     An embodiment also discloses a trimmer including the above mentioned trimmer head. 
     The upper cover assembly  001  is designed to be used in two modes, so the connection hole  003  in the side wall of the upper cover assembly  001  plays different roles in different modes. The connection hole  003  provides the mounting area for the first trimming assembly  100  when using the blade trimming mode; the connection hole  003  provides space for the second fixing part  22  in the second lower cover  02  to engage when using the second trimming assembly  200 . On the one hand, with the above-mentioned embodiments of the trimming head, only need to replace the blade and string components and the corresponding lower cover accordingly when the type of the cutting member need to be changed, and the upper cover assembly as the largest volume part is shared. In this way, the components that need to be replaced in the two trimming modes are relatively independent and compact, so that the cost of manufacturing and maintenance replacement can be reduced accordingly. On the other hand, the trimming line of the second trimming assembly is provided in the middle position of the lower cover, thus solving the problem of low efficiency when cutting grass with the conventional trimmer head, and reducing the difficulty of controlling the flatness of the lawn. In addition, the overall structure shape of the upper cover is used to provide a connection hole in its side wall, and the first base and holder are mounted inside the upper cover. One end of the holder extends from the connection hole, and the first cutting member is mounted at the part of the holder extending from the connection hole, and the part is closely adapted to the width direction of the connection hole. The holder, the first base and the upper cover are in a fastened state after the lower cover is fixedly connected, that is, the holder and the first base are equivalent to a whole. When the blade is impacted during the cutting, the part where the blade is mounted is under a huge circumferential force, and the circumferential force is transferred to the holder and the first base and is absorbed by the connection part between the holder and the first base and the connection hole. And the holder and the first base clamped by the lower cover can also share the force of the connection part. So, the impact resistance can be greatly enhanced under the combination. 
     The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The terminology used herein was chosen to best explain the principles of the embodiment, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.