Patent Publication Number: US-2021193413-A1

Title: Electric drill

Description:
CROSS-REFERENCE TO RELATED INVENTIONS 
     This invention claims the priority of CN application Serial No. 201911317292.0, filed on Dec. 19, 2019, the disclosures of which are hereby incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a power tool, and particularly to an electric drill. 
     BACKGROUND ART 
     Ground drills are widely used in seedling landscaping projects on sandy and hard soil for digging holes. The conventional drills use a two-stroke or four-stroke gasoline engine as the power source, which is easy to access and makes the drill work long hours. However, the vibration and noise of gasoline engine usually makes the operators unbearable, and professional workers are more likely to get occupational diseases after long-term use. Moreover, two-stroke or four-stroke gasoline engines have low energy efficiency, and burning fuels will inevitably generate pollutants. In general, the use of gasoline engines is unfriendly to humans and the environment. 
     Considering the mobility and the working efficiency, DC electric drill with electric motor powered by batteries becomes more popular in the market. Unlike the gasoline engine ground drill with operation by pulling the engine control member, the DC electric drill can be activated or deactivated by pressing the switch button, which makes the operation more convenient. However, the normal switch button structure may bring the safety issue of inadvertent actuation of the drill. 
     In view of the above, there is a need to provide an improved electric drill to solve the problems. 
     SUMMARY OF INVENTION 
     The objective of the present invention is to provide an electric drill which is provided with a self-locking button so that the electric drill can be started only when the switch and the self-locking button are triggered at the same time, thereby improving the safety performance of the electric drill. 
     In order to achieve the object, the present invention provides an electric drill, comprising: a bracket having a handle; a drill rod; a motor assembly mounted on the bracket for driving the drill rod to rotate; and a switch assembly mounted on the handle; wherein, the switch assembly comprises: a first micro switch configured to activate or deactivate the motor assembly; a switch pivotably mounted on the handle through a pivot, and cooperating with the first micro switch; and a self-locking button engaged with the switch and configured as: when the self-locking button is in a first state, the self-locking button abuts against the switch to prevent the switch from rotating around the pivot; when the self-locking button is in a second state, the self-locking button is disengaged with the switch, and the switch can rotate around the pivot. 
     As a further improvement of the invention, an abutting arm is arranged on a side of the self-locking button facing the switch, and a receiving groove is arranged on a side of the switch facing the self-locking button; wherein when the self-locking button is in the first state, the abutting arm and the receiving groove are misaligned, and the abutting arm abuts against the switch; and wherein when the self-locking button is in the second state, the abutting arm and the receiving groove are in alignment. 
     As a further improvement of the invention, a moving direction of the self-locking button from the first state to the second state is parallel to or perpendicular to an axial direction of the pivot. 
     As a further improvement of the invention, a through hole is arranged on a side of the handle facing the motor assembly, and wherein the self-locking button is partially protruded from the through hole. 
     As a further improvement of the invention, the switch assembly comprises a switch reset elastic element for resetting the switch, and wherein one end of the switch reset elastic element abuts against the handle and the other end thereof abuts against the switch. 
     As a further improvement of the invention, the switch assembly comprises a self-locking button reset elastic element for resetting the self-locking button, and wherein one end of the self-locking button reset elastic element abuts against the self-locking button, and the other end thereof abuts against the handle. 
     As a further improvement of the invention, the switch assembly further comprises a self-locking button reset elastic element for resetting the self-locking button under the action of the self-locking button reset elastic element. 
     As a further improvement of the invention, the electric drill further comprises a reversing assembly, wherein the reversing assembly comprises a second micro switch and a reversing button cooperating with the second micro switch; and wherein the second micro switch is configured as: the motor assembly reverses only when the first micro switch and the second micro switch are both triggered simultaneously. 
     As a further improvement of the invention, the handle comprises a first handle and a second handle disposed opposite to each other; and wherein the switch assembly is arranged on the first handle and the reversing assembly is arranged on the second handle. 
     As a further improvement of the invention, the second handle comprises a groove for accommodating the reversing button; and wherein the reversing button partially protrudes from the groove in a direction facing the motor assembly. 
     As a further improvement of the invention, the bracket includes a mounting portion for mounting the motor assembly, an operating portion located at the periphery of the mounting portion, and a connecting portion connecting the mounting portion and the operating portion. 
     As a further improvement of the invention, at least one illumination lamp is positioned on a side of the operation portion facing the drill rod. 
     As a further improvement of the invention, the operation portion is rectangular, and wherein the at least one illumination lamp is located at a corner of the operation portion. 
     As a further improvement of the invention, the electric drill further comprises an illumination lamp, wherein the illumination lamp is turned on when the first micro switch is triggered. 
     As a further improvement of the invention, the electric drill further comprises a transmission mechanism, wherein the transmission mechanism engages with the drill rod and the motor assembly, wherein the transmission mechanism comprises a gear assembly and a gear box for accommodating the gear assembly; wherein the gear box includes a first rotation stopper, and wherein the bracket comprises a second rotation stopper that cooperates with the first rotation stopper to transmit the force received by the gear box to the bracket. 
     As a further improvement of the invention, the gear box comprises a box body and a cover matched with the box body, and wherein the box body and the box cover are respectively located on opposite sides of the bracket. 
     As a further improvement of the invention, the first rotation stopper comprises a first positioning member disposed on an end of the box body close to the bracket; and the second rotation stopper comprises a second positioning member arranged on a side of the bracket facing the box body; and wherein the second positioning member engages with the first positioning member. 
     As a further improvement of the invention, the first rotation stopper comprises a first fixing member disposed on a side of the box cover facing the bracket; and the second rotation stopper comprises a second fixing member arranged on a side of the bracket facing the box cover; and wherein the second fixing member engages with the first fixing member. 
     The beneficial effect of the present invention is that: the electric drill of the present invention is provided with a self-locking button so that the electric drill can be started only when the switch and the self-locking button are triggered at the same time, thereby improving the safety performance of the electric drill. 
     The above general description and the following detailed description are intended to be illustrative and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an electric drill of the present invention. 
         FIG. 2  is a schematic view showing the engagement between a bracket, a motor assembly and a transmission mechanism. 
         FIG. 3  is an exploded, perspective view of the transmission mechanism. 
         FIG. 4  is an exploded, perspective view of the transmission mechanism taken from another aspect. 
         FIG. 5  is an exploded, perspective view of a primary gear assembly. 
         FIG. 6  is a perspective view of a secondary gear assembly. 
         FIG. 7  is a partial enlarged, exploded perspective view of a box cover and the bracket. 
         FIG. 8  is a perspective view of the bracket. 
         FIG. 9  is a perspective view of the bracket taken from another aspect. 
         FIG. 10  is a schematic view showing the engagement between the bracket, the transmission mechanism and a shell without top wall. 
         FIG. 11  is a structural schematic view of a switching assembly. 
         FIG. 12  is a schematic view showing an engagement between a switch and a self-locking button. 
         FIG. 13  is a structural schematic view of a reverse assembly. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     The exemplary embodiment will be described in detail herein, and the embodiment is illustrated in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements. The embodiment described in the following exemplary embodiment does not represent all embodiments consistent with present invention. On the contrary, they are only examples of devices, systems, machines, and methods consistent with some aspects of the invention as detailed in the appended claims. 
     Reference will now be made to the drawing figures to describe the embodiments of the present disclosure in detail. In the following description, the same drawing reference numerals are used for the same elements in different drawings. 
     Referring to  FIG. 1  and  FIG. 2 , the present invention discloses an electric drill  100 , including a drill rod  50 , a motor assembly  60 , a battery pack  70  that provides power to the motor assembly  60 , a transmission mechanism  10 , a bracket  20 , a switch assembly  30 , and a reversing assembly  40  (as shown in  FIG. 9 ). The drill rod  50  is an operating mechanism for performing the functions of the electric drill  100 . The motor assembly  60  drives the drill rod  50  to rotate through the transmission mechanism  10 . 
     Referring to  FIG. 3 ,  FIG. 4  and  FIG. 2 , the transmission mechanism  10  cooperates with the drill rod  50  and the motor assembly  60  so as to transmit the power output by the motor assembly  60  to the drill rod  50 . The transmission mechanism  10  includes a gear assembly and a gear box  15  accommodating the gear assembly. The gear assembly includes a primary planet carrier  11 , a primary gear assembly  12 , a secondary planet carrier  13  and a secondary gear assembly  14 . One end of the primary planet carrier  11  comprises a plurality of primary planetary shafts  111  engaged with the primary gear assembly  12 , and the other end comprises a sun gear  112  engaged with the secondary gear assembly  14 . 
     Referring to  FIG. 5 , the primary gear assembly  12  includes a primary ring gear  121 , a primary gear set  122  located in the primary ring gear  121 , and a fixing plate  123 . A side wall of the primary gear  121  facing away from the primary gear set  122  comprises flat walls  1211  and a fixing portion  1212  located between the adjacent flat walls  1211 . The fixing portion  1212  extends throughout the thickness of the primary ring gear  121  along the axial direction of the primary ring gear  121 . The fixing portion  1212  comprises a slot on a side facing a side wall of the gear box  15 , and the fixing portion  1212  is configured as a semi-circular portion. An end of the primary ring gear  121  away from the secondary gear assembly  14  comprises a retaining groove  1213 . The primary gear set  122  includes at least two groups of primary planetary gear set  1221 . The at least two primary planetary gear sets  1221  are overlapped in the axial direction of the primary ring gear  121 , and are pivotably mounted on the primary planetary gear shaft  111 , and the outer side of the primary planetary gear set  1221  engages with the primary ring gear  121  and the inner side thereof engages with a central gear (not shown) arranged on the output shaft of the motor assembly  60 . Each group of the primary planetary gear set  1221  includes four planetary gears, and the four planetary gears are evenly distributed on the peripheral edge of the primary ring gear  121  along the axial direction. In this embodiment, the number of the primary planetary gear set  1221  is two, and each set of the primary planetary gear set  1221  includes four gears, but in other embodiments, the number of the primary planetary gear set  1221  (=2) and the number of gears contained in each group of the primary planetary gear set  1221  can be arranged as required. Since the primary gear set  122  comprises at least two primary planetary gear sets  1221 , the load carried by the primary gear set  122  is relatively uniform, so that the primary planet carrier  11  can withstand a larger load, and can output a stable force. Moreover, the service life of the transmission mechanism  10  can be extended due to the uniform load carried by the primary gear set  122 . The fixing plate  123  is located at an end of the primary gear assembly  12  away from the secondary gear assembly  14  to limit the primary planetary gear set  1221  within the primary ring gear  121 . The fixing plate  123  includes a main body  1231 , an elastic resisting portion  1232  extending from the main body  1231 , and a connecting portion  1233  connecting the main body  1231  and the elastic resisting portion  1232 . The main body  1231  has an annular shape. The connecting portion  1233  is accommodated in the retaining groove  1213 , and the elastic resisting portion  1232  is bend and substantially V-shaped. One end of the elastic resisting portion  1232  facing away from the connecting portion  1233  elastically resists the side wall of the gear box  15 , so as to secure the fixing plate  123  in the primary gear assembly  12 . 
     Referring to  FIGS. 3 and 4 , one end of the secondary planetary carrier  13  is provided with a plurality of secondary planetary gear shafts  131  engaged with the secondary gear assembly  14 , and the other end is provided with an output shaft  132  engaged with the drill rod  50 . Referring to  FIG. 6 , the secondary gear assembly  14  includes a secondary gear ring  141  and a secondary planetary gear set  142  located in the secondary gear ring  141 . A side wall of the secondary ring gear  141  facing away from the secondary planetary gear set  142  comprises a flat wall  1411  and a fixing portion  1412  located between the adjacent flat walls  1411 . The fixing portion  1412  extends throughout the thickness of the secondary gear  141  along the axial direction of the secondary gear  141 . The fixing portion  1412  comprises a slot on a side facing the side wall of the gear box  15 , and the fixing portion  1412  is a configured as a semi-circular slot. The secondary planet gear set  142  is pivotably arranged on the secondary planet gear shaft  131 , and the outer side of the secondary planet gear set  142  engages with the secondary ring gear  141  and the inner side thereof engages with the sun gear  112 . In this embodiment, the secondary planet gear set  142  includes five gears, but in other embodiments, the number of the gears of the secondary planet gear set  142  can be configurable according to the requirements without limitation. Referring together to  FIGS. 3, 4 and 7 , the gear box  15  accommodates the primary planet carrier  11 , the primary gear assembly  12 , the secondary planet carrier  13  and the secondary gear assembly  14 , and includes a box body  151  and a box cover  152  matched with the box body  151 . The box body  151  and the box cover  152  are respectively located on opposite sides of the bracket  20 . The gear box  15  includes a first rotation stopper comprising a first positioning member  1511  disposed on an end of the box body  151  close to the bracket  20  and a first fixing member  1521  disposed on a side of the box cover  152  facing the bracket  20 . The box body  151  includes a first resist member  1512  on a sidewall thereof facing away from the gear assembly. A side wall of the box body  151  facing the gear assembly also includes positioning ribs  1513  being in cooperating with the flat wall  1211  and the flat wall  1411 . Since the contact surfaces of the flat walls  1211 ,  1411  and the positioning rib  1513  are flat, the contact area between the box body  151  and the primary gear ring  121  and the secondary gear ring  141  can be effectively increased, and this also makes it easy to assemble the gear box  15 , the primary gear ring  121 , and the secondary gear ring  141 . In the present embodiment, the number of the positioning rib  1513  is four, and they are evenly arranged on the side wall of the box body  151 . The numbers of the flat walls  1211 ,  1411  are both four, and they are evenly arranged on side walls of the primary gear ring  121 , the secondary gear ring  141 , respectively. In other embodiments, the numbers of the positioning rib  1513 , the flat walls  1211 ,  1411  can be determined according to the requirements without limitation. The box body  151  also includes a box assembling hole  1514  engaging with the fixing portion  1212  and the fixing portion  1412 . The box cover  152  has a cover assembling hole  1522 . The cover assembling hole  1522 , the box assembling hole  1514 , the fixing portion  1212  and the fixing portion  1412  engage with each other through a screw, thereby fixing the box body  151 , the gear assembly, the box cover  152  together. 
     Referring to  FIGS. 8, 9  and  FIG. 7 , the bracket  20  includes a mounting portion  21 , an operating portion  22  located at the periphery of the mounting portion  21 , and a connecting portion  23  connecting the mounting portion  21  and the operating portion  22 . The motor assembly  60  and the transmission mechanism  10  are mounted on the mounting portion  21 . The mounting portion  21  includes a second rotation stopper that cooperates with the first rotation stopper to transmit the force received by the gear box  15  to the bracket  20 . The second rotation stopper includes a second positioning member  211  arranged on a side of the mounting portion  21  facing the box body  151 , and a second fixing member  212  arranged on the side of the mounting portion  21  facing the box cover  152 . The second positioning member  211  engages with the first positioning member  1511 , and the second fixing member  212  engages with the first fixing member  1521 , so that the force received by the gear box  15  can be transmitted to the bracket  20  through the first positioning member  1511 , the second positioning member  211 , the first fixing member  1521 , and the second fixing member  212 , thereby effectively preventing connection between the gear box  15  and the bracket  20  from loosening. In the present embodiment, the first positioning member  1511  is a positioning recess, and the second positioning member  211  is a positioning protrusion, while in other embodiments, the first positioning member  1511  may also be a positioning protrusion, and the second positioning member  211  can also be a positioning recess matching with the positioning protrusion. In the present embodiment, the first fixing member  1521  is a protrusion extending downwards from the box cover  152 , and the second fixing member  212  is a recess matching with the protrusion. The cover assembling hole  1522  is located on the first fixing member  1521 . 
     Referring to  FIG. 10  and  FIG. 1 , the electric drill  100  also includes a shell  80  securely assembled on the bracket  20 . The motor assembly  60  and the transmission mechanism  10  are received in the shell  80 . A inner side wall of the shell  80  has a second resist member  81  matched with the first resist member  1512 . This arrangement makes that the force applied to the gear box  15  can be transmitted to the shell  80  through the first resist member  1512  and the second resist member  81 , and indirectly transmitted to the bracket  20 , thereby a loosening phenomenon between the gear box  15  and the bracket  20  can be effectively prevented, thus the user experience is effectively improved. In the present embodiment, the first resist member  1512  is a protrusion, and the second resist member  81  is a recess engaging with the protrusion, while in other embodiments, the first resist member  1512  may also be a recess and the second resist member  81  may be a protrusion. The operating portion  22  is substantially rectangular, and an illumination lamp  221  is positioned on a side of the operating portion  22  facing the drill rod  50 . In this embodiment, the number of the illumination lamps  221  is two, and they are located at one end of the operating portion  22  close to the battery pack  70 . Preferably, the number of the illumination lamps  221  is four, and they are located at four corners of the operating portion  22  respectively. By such an arrangement, a wide range of illumination area can be obtained, and the light emitted by the illumination lamp towards the working area can not be blocked by the drill rod  50 , thereby effectively improving the user experience. The operating portion  22  is also provided with a pair of handles, including a first handle  222  and a second handle  223  disposed opposite to each other. 
     Referring to  FIG. 11 ,  FIG. 12  and  FIG. 1 , the switch assembly  30  is assembled on the first handle  222 , and includes a first micro switch  31 , a switch  32 , a switch reset elastic element  33 , a self-locking button  34 , and a self-locking button reset elastic element  35 . The first micro switch  31  is configured to activate or deactivate the motor assembly  60 . The switch  32  is pivotably mounted on the handle  222  through a pivot  321 , and an end of the switch  32  facing away from the pivot  321  is provided with an abutting block  322  that cooperates with the first micro switch  31 . A receiving groove  323  is arranged on a side of the switch  32  facing the self-locking button  34 . One end of the switch reset elastic element  33  abuts against the first handle  222  and the other end abuts against the switch  32 . The self-locking button  34  includes a base  341  and an abutting arm  342  located on a side of the base  341  facing the switch  32 , and the abutting arm  342  is cooperating with the receiving groove  323 . One end of the self-locking button reset elastic element  35  abuts against the self-locking button  34 , and the other end abuts against the first handle  222 . Referring to  FIG. 8 , a through hole  2221  is arranged on a side of the first handle  222  facing the motor assembly  60 , and the self-locking button  34  partially protrudes from the through hole  2221  so as to be pressed by the operator. 
     The button  34  is configured in such a way that: when the self-locking button  34  is in the first state, the self-locking button  34  abuts against the switch  32  to prevent the switch  32  from rotating around the pivot  321 ; when the self-locking button  34  is in the second state, the self-locking button  34  is out of contact with the switch  32 , and the switch  32  can rotate around the pivot  321 . Specifically, when the self-locking button  34  is pressed (i.e., in the second state), the self-locking button reset elastic element  35  is elastically deformed, and the self-locking button  34  moves into the first handle  222  so that the abutting arm  342  and the receiving groove  323  are in alignment. At this time, pressing the switch  32  causes the switch  32  to rotate around the pivot  321 . The switch reset elastic element  33  is elastically deformed, and the abutting arm  342  enters into the receiving groove  323 , and the abutting block  322  abuts against the first micro switch  31 , so that the first micro switch  31  is activated. When the switch  32  is released, the switch  32  is reset under the action of the switch reset elastic element  33 ; when the self-locking button  34  is released, the self-locking button  34  is reset under the action of the elastic element  35  (i.e., in the first state). At this time, the abutting arm  342  and the receiving groove  323  are misaligned, and the abutting arm  342  abuts against the switch  32 , so that the switch  32  cannot rotate around the pivot  321 . Therefore, the electric drill  100  of the present invention will not be activated by accidentally touching the switch  32 , and a safety operation of the electric drill  100  is achieved. In the present embodiment, the moving direction of the self-locking button  34  from the first state to the second state is parallel to the axial direction of the pivot  321 , while in other embodiments, the moving direction from the first state to the second state of the self-locking button  34  may also be configured to be perpendicular to the axial direction of the pivot  321 . 
     Referring to  FIG. 13  and  FIG. 9 , the reversing assembly  40  is disposed on the second handle  223 , and includes a second micro switch  41 , a reversing button  42  engaged with the second micro switch  41 , and a reversing button reset elastic element  43 . The second handle  223  is provided with a groove  2231  for accommodating the reversing button  42 . The reversing button  42  partially protrudes from the groove  2231 , and the protruding portion thereof is located on a side of the second handle  223  facing the motor assembly  60 . When the reversing button  42  is pressed, the reversing button  42  retracts into the groove  2231 , the reversing button reset elastic element  43  is elastically deformed, and the reversing button  42  abuts against the second micro switch  41  so that the second micro switch  41  is triggered. When the reversing button  42  is released, the reversing button  42  is reset under the action of the reversing button reset elastic element  43 . In this embodiment, the second micro switch  41  is configured in such a way that: the motor assembly  60  reverses when and only when the first micro switch  31  and the second micro switch  41  are both triggered at the same time. With this arrangement, it is possible to prevent the electric drill  100  from reversing due to accidentally touching the reversing button  42 , thereby effectively improving the safety factor. In this embodiment, after any one of the first micro switch  31  and the second micro switch  41  is triggered, the illumination lamp  221  is turned on. 
     Compared with the prior art, the electric drill  100  of the present invention comprising the self-locking button  34  enables the electric drill  100  to be activated only when the switch  32  and the self-locking button  34  are triggered simultaneously, thereby improving the safety factor of the electric drill  100 . 
     The above embodiment is only used to illustrate present invention and not to limits the technical solutions described in present invention. The understanding of this specification should be based on those skilled in the art, although present invention has been described in detail with reference to the above embodiment. However, those skilled in the art should understand that those skilled in the art can still modify or equivalently replace present invention, and all technical solutions and improvements that do not depart from the spirit and scope of present invention should be within the scope of the claims of the invention.