Abstract:
A locking device includes an operating lever, a base and a repulsion generating member, wherein the operating lever has a releasing position and a locking position relative to the base, and the repulsion generating member is arranged between the base and the operating lever and generates a repulsion force for application to the operating lever during movement from the releasing position to the locking position. When the operating lever does not completely reach the locking position due to abnormal operation, the repulsion generating member will cause the operating lever to return to the releasing position thereby provide an indication. The locking device can thus provide an indication when the locking operation does not reach the correct position, thereby avoiding user confusion and abnormal operation.

Description:
RELATED APPLICATION INFORMATION 
     This application claims the benefit of CN 201310502603.7, filed on Oct. 23, 2013, the disclosure of which is incorporated herein by reference in its entirety. 
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to the field of garden tools, and more particularly to a locking device, and a telescopic rod and a mower including the locking device. 
     BACKGROUND OF THE DISCLOSURE 
     For electric tools having a pushing rod or an operating rod, in order to reduce volume during transportation and storage, the pushing rod or the operating rod is generally designed as two or more retractable sections. Therefore, a locking mechanism is needed to lock the relative position between the two sections of the pushing rod when stretching the pushing rod. Current locking mechanisms are located between a locking position and a releasing position, and cannot completely reach the locking position when the two sections of the pushing rod are retracted to the desired position. At that moment, the fastening force for the relative position between the two sections of the pushing rod is relatively small, therefore the pushing rod may be retracted during operation, which can affect the normal operation of the user. 
     SUMMARY 
     The objective of the present disclosure is to provide a locking device, and a telescopic rod and a mower including the locking device, which can provide an indication when the locking operation of the user does not reach the correct position, and thereby avoiding user confusion and abnormal operation. 
     To obtain the above objective, the present disclosure provides a locking device, including an operating lever, a base and a repulsion generating member, wherein the operating lever has a releasing position and a locking position relative to the base, and the repulsion generating member is arranged between the base and the operating lever and generates a repulsion force for application to the operating lever during the movement of the operating lever from the releasing position to the locking position. 
     The present disclosure further provides a telescopic rod, including an inner tube, an outer tube and a locking device, wherein the inner tube is slidably connected to the outer tube, the locking device locking the relative position between the inner tube and the outer tube, wherein the locking device includes a pivoting shaft, an operating lever, a base and a repulsion generating member, the base being sleeved on the outer tube and the pivoting shaft being arranged on the base, one end of the operating lever being provided with a locking member for rotating around the pivoting shaft relative to the base, the repulsion generating member being arranged between the base and the operating lever and generating a repulsion force for applying to the operating lever during the movement of the operating lever from the releasing position to the locking position. 
     The present disclosure also provides a mower including a main body, four wheels supporting the main body and a pushing handle connected to the main body. The pushing handle includes a telescopic rod, wherein the telescopic rod includes an inner tube, an outer tube and a locking device, wherein the inner tube is slidably connected to the outer tube, the locking device locking the relative position between the inner tube and the outer tube, wherein the locking device comprises a pivoting shaft, an operating lever, a base and a repulsion generating member, the base being sleeved on the outer tube and the pivoting shaft being arranged on the base, one end of the operating lever being provided with a locking member for rotating around the pivoting shaft relative to the base, the repulsion generating member being arranged between the base and the operating lever and generating a repulsion force for applying to the operating lever during the movement of the operating lever from the releasing position to the locking position. 
     The beneficial effect of the described devices lies in that, owing to the repulsion generating member being arranged between the base and the operating lever, the repulsion force is applied to the operating lever during the movement from the releasing position to the locking position, therefore, when the operating lever does not completely reach the locking position due to abnormal operation, the operating lever will return to the releasing position because of the repulsion force, and thereby provide an indication to the user. The described devices can also prevent the relative sliding between the inner tube and the outer tube of the telescopic rod of the mower when the inner tube and the outer tube do not extend to the position during the operating process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an exemplary locking device according to the description which follows. 
         FIG. 2  is a schematic view of the locking device of  FIG. 1  used in a telescopic rod. 
         FIG. 3  is an exploded view of the telescopic rod of  FIG. 2 . 
         FIG. 4  is a sectional schematic view of the locking device of the telescopic rod of  FIG. 2  in a releasing position. 
         FIG. 5  is a sectional schematic view of the locking device of the telescopic rod of  FIG. 2  in a locking position. 
         FIG. 6  is a sectional schematic view of the locking device of  FIG. 2  between the releasing position and the locking position. 
         FIG. 7  is also a sectional schematic view of an exemplary locking device between the releasing position and the locking position according to the description which follows. 
         FIG. 8  is also a sectional schematic view of an exemplary locking device between the releasing position and the locking position according to the description which follows. 
         FIG. 9  is a schematic view of a mower including the telescopic rod of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Exemplary locking devices will now be described in detail with reference to the drawings and specific embodiments. 
     As shown in  FIG. 1 , a locking device  100  includes a base  10 , a pivoting shaft  11 , an operating lever  12  and a repulsion generating member  13 . The pivoting shaft  11  is arranged on the base  10 , and one end of the operating lever  12  is provided with a locking member  12   a  for rotating around the pivoting shaft  11  relative to the base  10 , and the repulsion generating member  13  is arranged between the base  10  and the operating lever  12 . 
     In the illustrated device, the repulsion generating member  13  is a torsion spring with one end  13   a  connected to the base  10  and the other end  13   b  connected to the operating lever  12 . When the operating lever  12  is in a releasing position, the torsion spring is in a natural condition, and when the operating lever  12  is in a locking position, the torsion spring is in a compressed condition. When the operating lever  12  is in the releasing position, a relatively small pretension force may be applied to the torsion spring. 
       FIG. 2  is a schematic view of the locking device of  FIG. 1  used in a telescopic rod. As shown in  FIG. 2 , a telescopic rod  20  includes an inner tube  21 , an outer tube  22  and the locking device  100 . The inner tube  21  is slidably connected to the outer tube  22 , and the locking device  100  locks the relative position between the inner tube  21  and the outer tube  22 . The base  10  of the locking device  100  is sleeved on the outer tube  21 . 
     As shown in  FIGS. 1-6 , the outer tube  22  is provided with a through hole  22   a  and a compression member  22   b  which moves radially along the tube  22   b . When the operating lever  12  is rotated to the locking position, the locking member  12   a  passes through the through hole  22   a  to compress the inner tube  21 . The locking member  12   a  may also directly apply a force to the inner tube  21 , and the compression member  22   b  is used to enable the locking member  12   a  to fix the inner tube more firmly. 
     Furthermore, the inner tube  21  has a hole  21   a  and the outer tube  22  has a hole  22   c , and the operating lever  12  further includes a locking reinforcement member  12   b  which can be engaged with the hole  21   a  and the hole  22   c  simultaneously. In the illustrated example, the locking reinforcement member  12   b  is a post. 
     Additionally, the other end of the operating lever  12  opposite to the locking member  12   a  is provided with a friction portion  12   c , and when the operating lever  12  is rotated to the locking position, the friction portion  12   c  is tightly engaged with the outer wall  10   a  of the base  10 . 
     The illustrated, exemplary locking device may be operated as follows: when the locking device  100  is in the released state, the operating lever  12  is in the releasing position, and then the torsion spring is in a natural condition or maybe applying a relatively small pretension force. When the inner tube  12  and the outer tube  22  need to be locked, the operating lever is rotated towards the locking position by the user. At that moment, the operating lever  12  needs to overcome the torsion F1 of the torsion spring, and the arm of the force relative to the pivoting shaft  11  is L1, therefore the moment of torque is L1*F1. When the operating lever  12  is rotated to the locking position, the friction portion  12   c  is tightly engaged with the outer wall  10   a  of the base  10 . The friction force of the friction portion  12   c  applied by the outer wall  10   a  is F2, and the arm of the force relative to the pivoting shaft  11  is L2, therefore the moment of torque is L2*F2. As long as L2*F2 is larger than L1*F1, the operating lever  12  will be maintained in the locking position. 
     When the user rotates the operating lever  12  from the releasing position towards the locking position, the operating lever will stay in a middle position between the releasing position and the locking position due to the abnormal operation of the user. For example, in this embodiment, since the relative position between the inner tube  21  and the outer tube  22  is not stretched to a preset position, the hole  21   a  is not aligned with the hole  22   c , and the locking reinforcement member  12   b  can only be inserted into the hole  22   c , as in the situation shown in  FIG. 5 . Because the locking device  100  in the illustrated example further includes the repulsion generating member  13 , the operating lever  12  needs to overcome a torsion F1′ of the torsion spring, and the arm of the force relative to the pivoting shaft  11  is L1′, therefore the moment of torque is L1′*F1′. In that case, the operating lever will return to the releasing position under the action of the torsion F1′, which provide an indication to the user that the operating lever  12  is not locked in position, thereby reminding the user to check whether the relative position between the inner tube  21  and the outer tube  22  are stretched in position. 
     In the illustrated example the repulsion generating member  13  is a torsion spring, but the present disclosure is not limited to this. In other embodiments, the repulsion generating member  13  may also be a tower-shaped spring  13 ′ or two magnets  13 ″ a  and  13 ″ b  arranged opposite to each other, as shown in  FIGS. 7 and 8  respectively. 
     The example shown in  FIG. 7  has similar structures and operating process to that shown in  FIG. 1  and the difference only lies in that the repulsion generating member is a tower-shaped spring  13 ′. One end  13 ′ a  of the tower-shaped spring  13 ′ is connected to the base  10  and the other end  13 ′ b  is connected to the operating lever  12 . When the operating lever  12  is in the releasing position, the tower-shaped spring  13 ′ is in a natural condition or applies a relatively small pretension force. When the operating lever  12  is in the locking position, the tower-shaped spring  13 ′ is in a compressed condition. When the operating lever  12  is positioned between the releasing position and the locking position, the operating lever  12  will return to the releasing position under the action of the elastic force of the tower-shaped spring  13 ′ so as to provide an indication to the user. 
     The example shown in  FIG. 8  has similar structures and operating process to the example shown in  FIG. 1  and the difference only lies in that the repulsion generating member includes two magnets  13 ″ a  and  13 ″ b  arranged opposite to each other. One magnet  13 ″ a  is arranged on the base  10  and the other magnet  13 ″ b  is arranged on the operating lever  12 . The two ends of the two magnets  13 ″ a  and  13 ″ b  opposite to each other have the same polarity, for example, both are N pole. When the operating lever  12  is in the releasing position, the distance between the two magnets  13 ″ a  and  13 ″ b  is relatively large, therefore the repulsion force caused by the two magnets  13 ″ a  and  13 ″ b  is relatively small. When the operating lever  12  is in the locking position, the distance between the two magnets  13 ″ a  and  13 ″ b  is relatively small, therefore the repulsion force caused by the two magnets  13 ″ a  and  13 ″ b  is increased. When the operating lever  12  is positioned between the releasing position and the locking position, the operating lever  12  will return to the releasing position under the action of the repulsion force between the two magnets  13 ″ a  and  13 ″ b  so as to provide an indication to the user. 
     Additionally, in the above examples the operating lever has a rotating movement relative to the base, but the present disclosure is not limited to this. In other embodiments, the operating lever may also have a linear movement relative to the base, as long as the operating lever has a releasing position and a locking position relative to the base. 
     The present disclosure further provides a mower including the above telescopic rod.  FIG. 9  is a schematic view of the telescopic rod used in the mower. The operating principle of the mower  200  will not be described in detail herein. 
     Certainly, the telescopic rod may also be used in other garden tools having a pushing rod (e.g. a handle) or an operating rod, such as a trimmer or a pole saw. A telescopic rod  20  of the mower may be locked by the locking device  100 . Due to the abnormal operation of the user, the operating lever  12  will automatically return to the releasing position when it is positioned in a middle position between the releasing position and the locking position, thereby providing an indication to the user that the inner tube and the outer tube are not locked in position. As such, the exemplary devices can prevent the relative sliding between the inner tube and the outer tube when the inner tube and the outer tube are not in the locking position during the operating process, and thereby prevent the risk of damaging the user. 
     The present disclosure describes a repulsion generating member arranged between the base and the operating lever, therefore when the operating lever is positioned between the releasing position and the locking position due to abnormal operation, the operating lever will return to the releasing position because of the repulsion force, and thereby provide an indication to the user. As such, the exemplary devices can prevent the relative sliding between the inner tube and the outer tube of the telescopic rod when the inner tube and the outer tube do not extend to the position during the operating process, and thereby prevent the risk of damaging the user. 
     The above illustrates and describes basic principles, main features and advantages of the present disclosure. Those skilled in the art should appreciate that the above embodiments do not limit the present disclosure in any form. Technical solutions obtained by equivalent substitution or equivalent variations are intended to fall within the scope of the appended claims.