Patent ID: 12208500

DETAILED DESCRIPTION OF THE INVENTION

A power tool100having a control device1according to an embodiment of the present invention is illustrated inFIG.1, wherein the power tool100could be an electric screwdriver, an electric wrench, an electric drill, or other tools capable of driving and rotating workpieces. The control device1is disposed on the power tool100and is adapted to activate a motor M of the power tool100and set a rotating direction of the motor M. Referring toFIG.2toFIG.8, the control device1of the current embodiment includes a trigger mounting bracket10, a control circuit board20, a control trigger30, and a direction-switching button40.

The power tool100includes a case110and the motor M. The case110has a transmission portion112and a holding portion114extending downward from the transmission portion112, wherein the motor M is disposed in the transmission portion112, and the holding portion114is adapted to be held by a user. An inner space is formed between the transmission portion112and the holding portion114, wherein an end of the inner space facing the holding portion114has a first through-hole114a, and a second through-hole112ais formed at a position of the transmission portion112close to the first through-hole114a. The second through-hole112ais arranged vertically relative to the first through-hole114a. The control trigger30passes through the first through-hole114ato be located at the holding portion114and is located below the transmission portion112. The direction-switching button40passes through the second through-hole112ato be located at the transmission portion112. In order to illustrate easily, a first axis A1, a second axis A2, and a third axis A3that are perpendicular to one another are defined.

The trigger mounting bracket10is disposed on the holding portion114of the case110and includes a first body12and a second body14, wherein the first body12matches with the second body14along the second axis A2to form a receiving space S therebetween. The trigger mounting bracket10includes a top plate122and a front plate124connected to the top plate122and facing a front of the case110of the power tool100. The top plate122has a first positioning structure. In the current embodiment, the first positioning structure includes a plurality of bulges122aarranged along the second axis A2, wherein a number of the bulges122ais three as an example. However, the number of the bulges122acould be two or more than two in other embodiments. A top portion of the top plate122has at least one restricting block protruding upward. In the current embodiment, the at least one restricting block includes two restricting blocks that are respectively a first restricting block12aand a second restricting block14aand are respectively located on the first body12and the second body14. In other words, the first restricting block12aand the second restricting block14aare located on two opposite sides of the trigger mounting bracket10in the second axis A2.

In the current embodiment, at least one first guiding portion and a protruding member128are disposed on the front plate124, wherein the at least one first guiding portion includes two first guiding portions that are respectively a guiding rail126. The two guiding rails126are spaced by a distance in the third axis A3and extend along the first axis A1. Each of the guiding rails126includes a horizontal plate126aand a vertical plate126b, wherein a surface of the horizontal plate126aof one of the two guiding rails126faces a surface of the horizontal plate126aof the other guiding rail126, and the vertical plates126bof the two guiding rails126are respectively and erectly disposed on another surface of the two horizontal plates126a. The protruding member128is disposed between the two horizontal plates126aand extends along the first axis A1. The vertical plate126bof each of the guiding rails126extends in a direction away from the protruding member128along the third axis A3.

The control circuit board20is fixed on the trigger mounting bracket10. In the current embodiment, a part of the control circuit board20is disposed in the receiving space S of the trigger mounting bracket10, and another part of the control circuit board20is located out of the trigger mounting bracket10. The control circuit board20has a three-dimensional Hall sensor (hereafter called 3D Hall sensor H) and a controller C. In the current embodiment, the 3D Hall sensor H is located close to a junction between the top plate122and the front plate124and is close to one of the guiding rails126. The 3D Hall sensor H is adapted to detect a variation of a magnetic field in the first axis A1and the second axis A2and to respectively output a first signal and a second signal, wherein the first signal and the second signal could be an analog signal or a digital signal. The controller C receives the first signal and the second signal outputted by the 3D Hall sensor H and controls the motor M to operate based on the first signal and the second signal.

The control trigger30is disposed on the trigger mounting bracket10and is located in the first through-hole114aof the case110, and could be moved back and forth along the first axis A1. A first magnet S1is disposed on the control trigger30and correspondingly approaches or moves away from the 3D Hall sensor H along the first axis A1as the control trigger30moves, so that the 3D Hall sensor H could detect a position of the first magnet S1to correspondingly generate the first signal. The first signal has a corresponding parameter variation based on a variation of the position of the first magnet S1. For instance, the parameter variation of an analog signal could be a voltage variation, while the parameter variation of a digital signal could be a digital value variation.

In the current embodiment, the control trigger30has a trigger case32, at least one second guiding portion, a restricting protrusion36, and an extending arm38, wherein the trigger case32has two side plates32aspaced by a distance, and a space is formed between the two side plates32a. In the current embodiment, the at least one second guiding portion includes two second guiding portions that are respectively a guiding slot34extending along the first axis A1, wherein each of the guiding slots34includes a horizontal section34aand a longitudinal section34b, and an end of the longitudinal section34bcommunicates with the horizontal section34a. The longitudinal sections34bof the two guiding slots34face opposite directions, so that the two guiding slots34form an upper and lower symmetrical structure.

More specifically, each of the guiding slots34has a partition plate342and two bent plates344, wherein the partition plate342is located in the space, and two lateral sides of the partition plate342are respectively connected to the two side plates32a; the two bent plates344are located in the space and is adjacent to the partition plate342; each of the bent plates344has a horizontal plate section344aand a longitudinal plate section344b; the two horizontal plate sections344aare respectively connected to the two side plates32a; the two horizontal plate section344aand the partition plate342are spaced to form the horizontal section34a; the two longitudinal plate section344bface each other and are spaced to form the longitudinal section34b.

The restricting protrusion36is located between the two partition plates342and extends along the first axis A1, wherein the restricting protrusion36and the protruding member128of the trigger mounting bracket10are located on the same axis.

An end of the extending arm38is connected to the trigger case32and is located above the upper one of the guiding slots34. The extending arm38extends out of the trigger case32along the first axis A1and has a first receiving groove38aadapted to receive the first magnet S1and located on a side of the extending arm38in the second axis A2.

The two guiding rails126on the front plate124of the trigger mounting bracket10enter the two guiding slot34respectively from an open end of the two guiding slot34of the control trigger30, wherein the cooperative relationship between the guiding slot34and the guiding rails126mentioned above allows the control trigger30to move back and forth along the first axis A1. The horizontal plate126ais located in the horizontal section34a, and the vertical plate126bis located in the longitudinal section34b, thereby achieving stable positioning. In this way, the control trigger30could move between a first position P1shown inFIG.8and a second position P2shown inFIG.9on the guiding rails126of the trigger mounting bracket10along the first axis, thereby driving the first magnet S1to approach or move away from the 3D Hall sensor H along the first axis A1.

A spring50is disposed between the control trigger30and the trigger mounting bracket10and fits around the restricting protrusion36and the protruding member128, wherein two ends of the spring50respectively abut against a periphery of the restricting protrusion36of the control trigger30and a periphery of the protruding member128of the front plate124. Referring toFIG.8, when the control trigger30is at the first position P1without external force, the first magnet S1is kept away from the 3D Hall sensor H. Referring toFIG.9, when an external force is exerted to move the control trigger30to the second position P2, the first magnet S1approaches the 3D Hall sensor H, and the spring50is compressed to push the front plate124of the trigger mounting bracket10, wherein the restricting protrusion36is adjacent to the protruding member128for avoiding a body of the spring50bent and offset, and the trigger case32abuts against the front plate124of the trigger mounting bracket10. In practice, the restricting protrusion36could abut against the protruding member128when the control trigger30is moved to the second position P2. After the external force is released, the spring50rebounds and pushes the control trigger30back to the first position P1. In this way, the 3D Hall sensor H could detect the position of the first magnet S1to correspondingly generate the first signal when the control trigger30is moved between the first position P1and the second position P2.

The controller C determines the position of the first magnet S1based on a parameter of the first signal generated by the 3D Hall sensor H. For instance, if the first signal is an analog signal, the parameter could be a voltage, and the controller C could determine the position of the first magnet S1based on a magnitude of the voltage of the first signal, wherein when the control trigger30is at the first position P1, the first magnet S1is away from the 3D Hall sensor H, so the voltage of the first signal generated by the 3D Hall sensor H is minimum or zero, and the controller C controls the motor M stop running; as the control trigger30gets closer to the second position P2, the first magnet S1gets closer to the 3D Hall sensor H, the magnetic field sensed by the 3D Hall sensor H becomes stronger gradually, and the voltage of the first signal generated by the 3D Hall sensor H also gradually increases, thereby the controller C could control the motor M to perform corresponding actions according to the voltage of the first signal (e.g. make the rotation speed of the motor M be proportional to the voltage of the first signal). Similarly, if the first signal is a digital signal, the parameter could be a digital value, and the controller C could determine the position of the first magnet S1based on a magnitude of the digital value to correspondingly control the motor M.

In the current embodiment, the first guiding portions of the trigger mounting bracket10are the guiding rails126, and the second guiding portions of the control trigger30are the guiding slots34. However, these are not a limitation of the present invention; in other embodiments, the first guiding portion and the second guiding portion could be any complementary shapes, and the number of the first guiding portion and the second guiding portion could also be one. The advantage of the two first guiding portions and the two second guiding portions is that the force could be evenly distributed, so that the movement of the control trigger30could be smoother.

The direction-switching button40is located above the top plate122of the trigger mounting bracket10and is located in the second through-hole112aof the case110. In the current embodiment, a position of the direction-switching button40in the first axis A1and the third axis A3could be restricted by the second through-hole112aof the case110, so the direction-switching button40could only move along the second axis A2. In practice, the second through-hole112acould be disposed on the trigger mounting bracket10, for instance, an extending portion with a through-hole could extend from a top of the trigger mounting bracket10, wherein the through-hole is formed along the second axis A2to receive the direction-switching button40and restrict the position of the direction-switching button40in the first axis A1and the third axis A3.

The direction-switching button40has a button body42and a protruding arm44, wherein the button body42is located in the second through-hole112a, and a bottom of the button body42has a second receiving groove42aand at least one restricting groove422. A second magnet S2is disposed in the second receiving groove42a. In the current embodiment, the at least one restricting groove422includes two restricting grooves422respectively disposed on two sides of the second receiving groove42a, wherein a width of each of the restricting grooves422in the second axis A2is greater than a width of each of the restricting blocks (i.e., the first restricting block12aand the second restricting block14a) in the second axis A2. The two restricting grooves422are adapted to respectively receive the first restricting block12aand the second restricting block14aof the trigger mounting bracket10. In this way, the cooperative relationship between the two restricting grooves422and both the first restricting block12aand the second restricting block14acould restrict a moving distance of the direction-switching button40in the second axis A2, preventing the button body42of the direction-switching button40from being pushed out of the second through-hole112aof the case110along the second axis A2. An end of the protruding arm44is connected to the button body42and extends out of the button body42along the first axis A1. A positioning structure is disposed on a bottom of the protruding arm44and is adapted to match with the first positioning structure on the trigger mounting bracket10for positioning, thereby positioning the direction-switching button40at one of a plurality of positioning positions in the second axis A2, wherein the positioning positions are a first positioning position P1a, a second positioning position P2a, and a third positioning position P3a.

More specifically, the positioning structure includes a recess442, so that the direction-switching button40could be positioned by engaging the recess442of the protruding arm44with one of the bulges122a. Additionally, the positioning structure could further include at least one side notch444. In the current embodiment, the at least one side notch444includes two side notches444located on two lateral sides of the recess442in the second axis A2and formed at an edge of two lateral sides of the protruding arm44. When the recess442is engaged with one of the bulges122a, a part of another one of the bulges122athat is adjacent to the bulge122aengaged with the recess442is received in at least one of the side notches444. By receiving a part of another one of the bulges122athat is adjacent to the bulge122aengaged with the recess442through the side notches444, a width of the protruding arm44in the second axis A2could increase to enhance the strength of the structure, and a distance between any two of the bulges122athat are adjacent could be reduced, thereby reducing the distance that the direction-switching button40moves between the adjacent positioning positions.

The direction-switching button40located at the third positioning position P3ais illustrated inFIG.7,FIG.10, andFIG.11, at this time, the recess442of the positioning structure is engaged with the middle one of the bulges122a, and the two side notches444respectively receive a part of the bulges122alocated on two lateral sides of the bulge122ain the middle; the first restricting block12aand the second restricting block14aare respectively received in the two restricting grooves422; the second magnet S2is located directly above the 3D Hall sensor H, wherein the 3D Hall sensor H detects a position of the second magnet S2and correspondingly generates the second signal; if the second signal is an analog signal, a parameter of the second signal is a voltage; if the second signal is a digital signal, a parameter of the second signal is a digital value. In this way, the controller C could determine the position of the second magnet S2based on the parameter of the second signal.

The direction-switching button40located at the first positioning position P1ais illustrated inFIGS.12-14, at this time, the recess442of the positioning structure is engaged with the left one of the bulges122a, the side notch444on the right receives a part of the bulge122ain the middle, and the second restricting block14aabuts against a side wall of the restricting groove422on the right, thereby restricting the direction-switching button40from moving leftward; the second magnet S2is located on the upper left side of the 3D Hall sensor H; the 3D Hall sensor H could detect the position of the second magnet S2and correspondingly generates the second signal, and the controller C could determine the position of the second magnet S2based on the parameter of the second signal.

The direction-switching button40located at the second positioning position P2ais illustrated inFIGS.15-17, at this time, the recess442of the positioning structure is engaged with the right one of the bulges122a, the side notch444on the left receives a part of the bulge122ain the middle, and the first restricting block12aabuts against a side wall of the restricting groove422on the left, thereby restricting the direction-switching button40from moving rightward; the second magnet S2is located on the upper right side of the 3D Hall sensor H; the 3D Hall sensor H could detect the position of the second magnet S2and correspondingly generates the second signal, and the controller C could determine the position of the second magnet S2based on the parameter of the second signal.

By positioning the direction-switching button40at the first positioning position P1a, the second positioning position P2a, or the third positioning position P3a, the second signal could be correspondingly generated based on the different positions of the second magnet S2. In other words, the parameter of the second signal on the three positioning positions would be different, so the controller C could determine that the direction-switching button40is located at the first positioning position P1a, the second positioning position P2a, or the third positioning position P3abased on the parameter of the second signal. When designing a program code of the controller C, it is possible to predefine that the direction-switching button40performs three different functions respectively when it is located at the three positioning positions; for example, a first function: when the direction-switching button40is located at the first positioning position P1a, a rotating direction of the motor M could be set as a forward rotation direction, and the controller C controls the motor M to rotate forward when the control trigger30is pressed; a second function: when the direction-switching button40is located at the second positioning position P2a, a rotating direction of the motor M could be set as a reverse direction, and the controller C controls the motor M to reverse when the control trigger30is pressed; and a third function: when the direction-switching button40is located at the third positioning position P3a, it could be set as a locking function, and the controller C does not control the rotation of the motor M when the control trigger30is pressed.

In practice, when the number of the bulges122ais two, the controller C could provide said first function and said second function to set the rotating direction of the motor M as forward or reverse.

With the aforementioned design, the operations of the control trigger30and the direction-switching button40could be detected by only one 3D Hall sensor H of the control circuit board20, which could not only solve the problem of poor contact of the conventional mechanical switches, but also reduce the use of electronic components to simplify the circuit.

It must be pointed out that the embodiments described above are only some preferred embodiments of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.