US 11,937,537 B2
Grass trimmer and control method for grass trimmer
Sanglong Wang, Nanjing (CN); and Jianpeng Guo, Nanjing (CN)
Assigned to Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed by Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed on Apr. 10, 2020, as Appl. No. 16/845,465.
Application 16/845,465 is a continuation of application No. PCT/CN2018/110927, filed on Oct. 19, 2018.
Claims priority of application No. 201710985907.1 (CN), filed on Oct. 20, 2017; and application No. 201711439441.1 (CN), filed on Dec. 27, 2017.
Prior Publication US 2020/0236845 A1, Jul. 30, 2020
Int. Cl. A01D 34/00 (2006.01); A01D 34/416 (2006.01); A01D 75/28 (2006.01)
CPC A01D 34/006 (2013.01) [A01D 34/416 (2013.01); A01D 75/285 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A grass trimmer, comprising:
an operating device configured for a user to operate; and
a grass trimmer head; and
a motor configured to drive the grass trimmer head,
wherein the grass trimmer head comprises:
a spool, configured for a grass trimmer line to wind around, capable of rotating around a first axis; and
a housing formed with an accommodating cavity configured to accommodate at least a part of the spool and formed with an aperture configured for the grass trimmer line to pass through,
wherein when the grass trimmer is mounted with the grass trimmer line, a part of the grass trimmer line protruding outside the housing is defined as an effective part of the grass trimmer line,
wherein the grass trimmer further comprises:
a controller configured to control the grass trimmer head to release the grass trimmer line when the grass trimmer head is mounted with the grass trimmer line and a length of the effective part is detected to be less than or equal to a preset value; and
a line feeding device configured to have a first working mode for preventing the grass trimmer head from releasing the grass trimmer line and a second working mode for allowing the grass trimmer head to release the grass trimmer line,
wherein the controller is connected to the motor, and the controller is capable of controlling the motor to accelerate from a first rotational speed at which the grass trimmer is in a normal trimming state to a second rotational speed so as to switch the grass trimmer head from the first working mode to the second working mode, and
wherein the line feeder comprises a movable block capable of rotating with rotation of the spool and sliding along a direction of a first straight line relative to the spool, the movable block is formed with an engagement portion, the housing is formed with a reception portion capable of cooperating with the engagement portion to cause the housing and the spool relatively stationary, when the line feeder is in the first working mode, the movable block slides to a position where the engagement portion and the reception portion cooperate with each other, when the line feeder is in the second working mode, the movable block slides to a position where the engagement portion and the reception portion are separated from each other.