the following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the scope of the invention hereinafter claimed , its application , or uses . referring to figs . land 2 ; a grass trimmer 100 includes a front housing 10 , a rear housing 20 , a motor 30 , a battery pack 40 , a trimmer head 50 , a connecting means 60 and a shield 70 . the front housing 10 is disposed at the front of the grass trimmer 100 and the rear housing 20 is disposed at the rear of the grass trimmer 100 . the front and rear herein referenced are used only to indicate a relative positional relationship not an absolute positional relationship . the motor 30 is received in the front housing 10 . the trimmer head 50 is driven by the motor 30 and connected to a cutting member 51 which is used to cut grass . the cutting member 51 may be a trimmer line or a cutting blade . it should be noted that the trimmer head 50 can be replaced by other tool heads of others gardening tools . the battery pack 40 provides the power to the motor 30 and is capable of detachably connecting with the rear housing 20 . the connecting means 60 connects the front housing 10 and the rear housing 20 as a whole . the shield 70 is fixed to the front housing 10 for protecting users . as shown in fig2 and fig3 , the connecting means 60 includes a connecting tube assembly 61 that extends along a first direction 101 . the connecting tube assembly 61 includes a first connecting tube 61 a and a second connecting tube 61 b . the connecting means 60 also includes a connecting base 62 . the connecting base 62 interconnects the first connecting tube 61 a and the second connecting tube 61 b . the first connecting tube 61 a is connected to the front housing 10 . the second connecting tube 61 b is connected to the rear housing 20 . the connecting means 60 forms an air channel 60 a for allowing an airflow to pass there through . as shown in fig2 - 4 , the front housing 10 includes a receiving portion 11 which forms a receiving chamber 11 a for receiving the motor 30 and a coupling portion 12 for coupling with the first connecting tube 61 . the coupling portion 12 is used to connect the receiving chamber 11 a and the air channel 60 a . particularly , the receiving portion 11 and the coupling portion 12 are manufactured as one - piece . as shown in fig3 , the shield 70 is installed to the connecting housing 12 of the front housing 10 . the connecting housing 12 extends along a direction away from the side wall of the motor housing 11 and the extension direction oblique to and intersects with a rotating axis of the motor 30 . the connecting housing 12 defines a connecting chamber interconnecting with the battery chamber . the first connecting tube 61 a is installed through into the connecting chamber . the connecting housing provides a first mounting aperture for fixing the shield 70 . in the illustrated embodiment , the first mounting aperture is a threaded hole . the shield 70 is fixed to the connecting housing 12 by a bolt fastened to a threaded hole . this has the advantage of providing a low cost construction without additional parts as well as providing convenient installation and disassembly . generally , the cutting member 51 is a trimmer line . the trimmer line may abrade after use for a long time period of time which may affect the cutting quality . as shown in fig5 , a blade 71 is fixed at the inside of the shield 70 for cutting the trimmer line . as shown in fig5 , the blade 71 is constructed as an l shape . the blade 71 has a cutting edge 711 and an installing section 712 for fixing it . the cutting edge 711 is substantially perpendicular to the installing section 712 . the shield 70 provides a second mounting aperture . particularly , the second mounting aperture is a threaded hole . the blade 71 is fixed to the shield 70 by a bolt fastened to a threaded hole . the cutting edge 711 extends along a direction away from the shield 70 when the blade 71 is fixed to the shield 70 . as shown in fig2 - 3 and fig6 - 10 , the grass trimmer 100 further includes a trigger switch 81 , a speed - control switch 82 , a first connecting wire 83 , a speed - control button 84 , a trigger 85 , a second connecting wire 86 and a circuit board 87 while the rear housing 20 includes a handle portion 21 , a connecting portion 22 and an accommodating portion 23 . the trigger switch 81 is capable of activating the motor 30 and the trigger 85 is used to control the trigger switch 81 . the speed - control switch 82 is capable of controlling the rotational - speed of the motor 30 and the speed - control button 84 is used to control the speed - control switch 82 . the circuit board 87 is used to electrically connect the motor the battery pack . the first connecting wire 83 is used to electrically connect the circuit board 87 to the speed - control switch 82 . the second connecting wire 86 is used to electrically connect the circuit board 87 to the motor 30 . the circuit board 87 is disposed inside the connecting portion 22 . the handle portion 21 is intended to be gripped by the user when the user uses the grass trimmer 100 . the handle portion 21 extends substantially along a first direction 101 . as shown in fig8 , the rear housing 20 forms a clip structure 24 for clipping the first connecting wire 83 at the inside of the handle portion 21 . the clip structure 24 may include two claws 24 a , 24 b for contact the first connecting wire 83 at opposite sides of the first connecting wire 83 . the claws 24 a and 24 b project inwardly . as shown in fig9 , the inserting part of the second connecting tube 61 b in the rear housing 20 forms a wire slot 611 for allowing the first connecting wire 83 and the clip structure 24 to pass there through . the wire slot 611 allows the size of handle portion 21 to be smaller . the connecting portion 22 is used to detachably connect with the battery pack . the handle portion 21 is located between the motor 30 and the connecting portion 22 . as shown in fig1 , when the battery pack 40 is connected to the rear housing 20 , at least one part of the battery pack 40 is exposed outside of the rear housing 20 for better heat dissipation . as shown in fig7 , the rear housing 20 forms a support surface 223 to support the arm of the user when the user uses the ipsilateral hand to grip the handle portion 21 . the direction 102 in which the support surface 223 substantially extends along and the length direction ( first direction 101 ) of the handle portion 21 intersect at an obtuse angle β . the obtuse angle β may range from 100 ° to 170 °. particularly , the angle β may range from 120 ° to 160 °. the support surface 223 will decrease weariness of users when they use the grass trimmer 100 for a long time . the battery pack 40 has battery pack terminals , and the grass trimmer 100 has a connecting terminal 222 for electrically connecting with the battery pack terminals at the connecting portion 22 . the battery pack 40 is capable of coupling to the connecting portion 22 along the directions which are parallel to the first direction 101 . the accommodating portion 23 is located between the motor 30 and the handle portion 21 and forms an accommodating chamber 23 a which is used to accommodate the trigger switch 81 and the speed - control switch 82 . as shown in fig1 , the speed - control button 84 is slidably connected with the rear housing at the accommodating portion 23 . when a user operates the speed - control button 84 to slide to different positions , the motor 30 outputs different rotatational - speed . as shown in fig2 , fig3 , and fig6 - 10 , the rear housing 20 forms a housing chamber 20 a which includes the accommodating chamber 23 a , and the housing chamber 20 a is formed from the connecting portion 22 to the accommodating portion 23 . the trigger switch 81 and the circuit board 87 are all accommodated in the housing chamber 20 a . the grass trimmer 100 further includes a fan 31 inside the front housing 10 and the fan 31 is driven by the motor 30 . when the fan 31 rotates , it generates an airflow which flows air from the rear housing 20 to the front housing 10 by passing the air through the air channel 60 a . for cooling the electrical components inside the rear housing 20 , the rear housing 20 forms a plurality of air inlets to allow the air to flow into the rear housing 20 . specifically , the rear housing 20 forms a first air inlet 221 at the connecting portion 22 and a second air inlet 231 at the accommodating portion 23 so as to cause the air flow to pass through the circuit board 87 and the trigger switch 81 . the above illustrates and describes basic principles , main features and advantages of the present invention . those skilled in the art should appreciate that the above embodiments do not limit the present invention in any form , technical solutions obtained by equivalent substitution or equivalent variations all fall within the scope of the present invention .
a gardening tool such as a grass trimmer is provided with a tool head , a motor for driving the tool head , a front housing for accommodating the motor , a trigger switch for activating the motor , a trigger operable to control the trigger switch , a battery pack for providing electric energy to the motor , a circuit board for electrically connecting the motor to the battery pack , and a rear housing for accommodating the circuit board . the rear housing forms a housing chamber for accommodating the trigger switch , the circuit board , and wires between the circuit board and the trigger switch .