CN209880452U - Reversing brake device of direct current electric tool switch and direct current electric tool switch - Google Patents

Abstract

The utility model provides a switching-over brake equipment and direct current electric tool switch of direct current electric tool switch belongs to electric switch technical field, and wherein direct current electric tool switch's switching-over brake equipment includes: the reversing device is connected between the motor and the direct-current power supply and changes the direction of current entering the motor through switching; the brake device is used for directly and electrically connecting two electric connection ends with two ends of the motor respectively in a closed state so as to form a closed loop with the motor; the utility model discloses a switching-over brake equipment when the switching-over device switches over, and brake equipment is in the closure state, and the closed circuit that brake equipment and motor formed can in time consume the great instantaneous armature current that the motor rotated the production to avoid the switching-over device to appear drawing the arc when switching over, avoid drawing the spark that produces behind the arc and damage the switch, thereby improve the life of switch.

Description

Reversing brake device of direct current electric tool switch and direct current electric tool switch

Technical Field

The utility model relates to an electric switch technical field, concretely relates to switching-over brake equipment and direct current electric tool switch of direct current electric tool switch.

Background

A dc power tool switch, such as a switch of an electric drill, generally has a reversing device, and the direction of the dc power tool switch can be changed by switching the reversing device.

For example, chinese patent document CN208368375 discloses a dc electric tool switch, which includes a button and a housing, and a push rod, a moving contact and a static contact are disposed in the housing. The button is connected with the moving contact through the push rod, and then the contact or disconnection between the moving contact and the fixed contact is controlled by pressing the button. The reversing shifting handle assembly with the function of forward and reverse rotation is arranged on the shell, and the reversing elastic sheet with the upper station and the lower station in the shell is driven to rotate to contact with the corresponding static contact piece on the shell, so that forward and reverse rotation reversing is realized.

In the switch of the prior art dc electric tool, as shown in fig. 2, a switch circuit controls a normally closed contact through a switch button, and the normally closed contact and the motor form a closed loop through a reversing device. When the button is pressed down, the normally closed contact is disconnected, and the motor can be driven to rotate after the current of the power supply is led to the motor; when the button is released, the normally closed contact is driven by the spring to close, and before the reversing device is switched, the motor is short-circuited by a loop formed by the normally closed contact at the moment, so that instantaneous armature current generated by the rotation of the motor can be consumed. When the motor needs to perform reversing rotation, the reversing elastic sheet moves by driving the reversing shifting handle, and the direction of current of the power supply entering the motor can be switched, so that the motor is reversed.

In the practical use of a switch for a dc power tool, after the switch button is released, the motor continues to rotate for a short period of time due to inertia. In this period, because the rotation of motor will produce instantaneous armature current, and adopt above-mentioned switching circuit, if the operation of operating personnel is more urgent, before the motor stall, just carry out the switching-over operation, at this moment, because great instantaneous armature current in the motor, at the switching-over shell fragment and the contact moment of static contact piece separation, the arc phenomenon all can appear drawing, and then produce the spark. This can cause damage to the switch and affect the life of the switch.

SUMMERY OF THE UTILITY MODEL

Therefore, the to-be-solved technical problem of the utility model lies in overcoming the direct current electric tool switch among the prior art, when commuting, the motor can be because the instantaneous armature current that inertia rotation produced can be through the switching-over device, consequently probably can make the switching-over shell fragment of switching-over device produce the defect of arc spark to when providing the armature current that can make the motor produce and release, can not be through the switching-over brake equipment of switching-over device.

In order to solve the technical problem, the utility model provides a switching-over brake equipment, include:

the reversing device is connected between the motor and the direct-current power supply and changes the direction of current entering the motor through switching;

and the brake device is directly connected to two ends of the motor and forms a closed loop with the motor in a closed state.

Preferably, the brake device includes:

the switch button is fixedly connected with the top end of the movable rod;

the movable rod is connected in the switch shell in a sliding way;

the brake moving contact is arranged in the switch shell and is linked with the movable rod;

the contact spring is connected between the switch shell and the brake moving contact and has a biasing force for keeping the contact on the brake moving contact to deviate towards the direction of a connection state;

the first switch-on point is electrically connected with one end of the motor and is electrically connected with a contact on the brake moving contact when the brake device is in a closed state;

and the second connecting point is electrically connected with the other end of the motor and is electrically connected with the other contact on the brake moving contact in a contact manner when the brake device is in a closed state.

Preferably, when the brake device is in a disconnected state, one contact of the brake moving contact is electrically connected with one end of the motor.

As a preferred scheme, the brake moving contact comprises:

the support end is positioned in the middle of the brake moving contact, is connected in the switch shell in a supporting way and is electrically connected with the second connecting point;

the tilting tail end is positioned at one end part of the brake moving contact and tilts towards one side;

and the first contact is positioned at the other end of the brake moving contact opposite to the warping tail end and is electrically connected with the first contact point when the brake device is in a closed state.

Preferably, the bottom of the movable rod is provided with a bump, and when the movable rod is pressed downwards, the bump can abut against the raised tail end, so that the first contact is raised, and then the first contact is separated from the first connection point.

Preferably, the brake moving contact is slidably disposed in the switch housing.

As a preferred scheme, the brake moving contact comprises:

the first contact is positioned at the top of the brake moving contact and is electrically connected with the first contact point when the brake device is in a closed state;

and the second contact is positioned at the bottom of the brake moving contact and is electrically connected with the second contact point when the brake device is in a closed state.

As preferred scheme, the brake moving contact still includes:

the connecting ring is connected to the upper end of the brake moving contact, the bottom of the movable rod is provided with a connecting block inserted in the connecting ring, and when the movable rod is pressed downwards, the connecting block can abut against the brake moving contact to enable the brake moving contact to slide downwards, so that the first contact and the second contact are separated from the first connection point and the second connection point respectively.

As preferred scheme, the brake moving contact still includes:

the connecting piece is connected to the upper end of the brake moving contact, the bottom of the movable rod is provided with an abutting surface used for abutting against the connecting piece, when the movable rod is pressed downwards, the abutting surface can abut against the brake moving contact to enable the brake moving contact to slide downwards, and therefore the first contact and the second contact are separated from the first connection point and the second connection point respectively.

The utility model also provides a direct current electric tool switch, have any one of the above-mentioned scheme switching-over brake equipment.

The utility model discloses technical scheme has following advantage:

1. the utility model provides a switching-over brake equipment when the switching-over device switches over, and brake equipment is in the closure state, and the closed circuit that brake equipment and motor formed can in time consume the great instantaneous armature current that the motor rotated the production to avoid the switching-over device to appear drawing the arc when switching over, avoid drawing the spark that produces behind the arc and damage the switch, thereby improve the life of switch.

2. The utility model provides a switching-over brake equipment, brake equipment are the normally closed contact, when not pressing down the operation, can form closed circuit with the motor automatically to be convenient for consume the great instantaneous armature current that the motor rotated the production in time, when guaranteeing to commutate and switching, the switching-over device can not appear drawing the arc phenomenon.

3. The reversing brake device provided by the utility model drives the brake moving contact through the contact spring to ensure that the first connection point and the second connection point are communicated, thereby realizing the brake device as a normally closed contact; the brake moving contact is moved by overcoming the biasing force of the contact spring through the pressing of the movable rod, so that the communication between the first connection point and the second connection point is disconnected, and the brake device is changed into a disconnection state; namely, when the movable rod is pressed, the short circuit of the brake device to the motor is released, so that the motor can rotate.

4. The utility model provides a switching-over brake equipment, a contact of brake moving contact can remain throughout with the one end of motor to be connected, and at this moment, the movable rod can adopt the sliding mode contact with the brake moving contact, when pressing the movable rod downwards, the contact end perk of movable rod drive brake contact to the electricity of the first switch-on point of disconnection and second switch-on point is connected.

5. The utility model provides a switching-over brake equipment, brake moving contact slidable sets up in the switch casing, and at this moment, the movable rod need adopt relatively fixed to be connected with the brake moving contact, and when pushing down the movable rod, the movable rod can drive the brake moving contact and slide to the electricity of the first switch-on point of disconnection and second switch-on point is connected.

6. The utility model provides a direct current electric tool switch can be used to control direct current electric tool, like electric drill, electric hammer, electric screwdriver etc. owing to have any one in the above-mentioned scheme switching-over brake equipment, consequently have the aforesaid arbitrary advantage.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic circuit diagram of the commutation brake device of the present application.

Fig. 2 is a schematic circuit diagram of a prior art reversing brake device.

FIG. 3 is a front view, partially in section, of the internal structure of one embodiment of the subject reverse brake assembly.

Fig. 4 is a front view of the brake movable contact in fig. 3.

Fig. 5 is a schematic perspective view of the movable rod connected to the bottom of the switch button in fig. 3.

Fig. 6 is a schematic front view of the brake moving contact in fig. 3 in cooperation with the first contact point and the second contact point.

Fig. 7 is a schematic view of the switch button of fig. 3 after being pressed.

Fig. 8 is a front view, partially in section, showing the internal structure of a second embodiment of the reverse brake apparatus of the present application.

Fig. 9 is a front view of the brake movable contact of fig. 8.

Fig. 10 is a front view of the movable rod connected to the bottom of the switch button in fig. 8 engaged with the brake movable contact.

Fig. 11 is a front view of the brake movable contact of fig. 8 mated with a first contact and a second contact.

Fig. 12 is a schematic view of the switch button of fig. 8 after being pressed.

FIG. 13 is a right side view of the reverse brake apparatus of the present application.

Fig. 14 is a perspective view of the reversing lever.

Fig. 15 is a front view, partially in section, showing the internal structure of a third embodiment of the reverse brake apparatus of the present application.

Fig. 16 is a front view of the brake movable contact of fig. 15.

Fig. 17 is a schematic perspective view of the movable rod connected to the bottom of the switch button in fig. 15 and the brake movable contact in cooperation.

Fig. 18 is a front view of the brake movable contact of fig. 15 mated with a first contact and a second contact.

Fig. 19 is a front view of the brake movable contact of fig. 18 after actuation.

Fig. 20 is a front view, partially in section, of the internal structure of the reversing brake device after the brake moving contact is actuated.

Description of reference numerals:

1. a reversing brake device; 2. a housing; 3. a switch button; 4. a reversing device; 5. a brake moving contact; 6. a reversing lever; 7. a motor; 8. a brake device; 9. a return spring; 10. a first turn-on point; 11. a second turn-on point; 12. a contact spring; 13. a first contact; 14. a support end; 15. raising the tail end; 16. a bump; 17. a groove; 18. a slider; 19. connecting columns; 20. a contact piece; 21. a second contact; 22. a connecting ring; 23. connecting blocks; 24. a movable rod; 25. connecting sheets; 26. a contact surface.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

The embodiment provides a reversing brake device 1, as shown in fig. 3, which includes a housing 2, a switch button 3, a movable rod 24, a reversing device 4 and a brake moving contact 5. The reversing device 4 can be the same as the structure in the prior art, namely, the reversing rod 6 is rotated to switch the direction of current entering the motor 7, so that the forward and reverse rotation reversing of the motor 7 is carried out.

As shown in fig. 1, in the circuit schematic diagram of the commutation brake device, the commutation device 4 is connected between the motor 7 and the dc power supply, and changes the direction of current entering the motor 7 by switching. Two electric connection ends of the brake device 8 are respectively and directly electrically connected with two ends of the motor 7, and the brake device 8 and the motor 7 form a closed loop in a closed state.

As shown in fig. 2, which is a schematic circuit diagram of a reversing brake device in the prior art, a brake device 8 in the prior art forms a loop with a motor 7 through a reversing device 4; compared with the prior art, the two electrical connection ends of the braking device 8 of the embodiment are respectively and directly electrically connected with the two ends of the motor 7, and do not pass through the reversing device 4. When the brake device 8 is closed, the larger instantaneous armature current generated by the rotation of the motor 7 can be consumed in time without passing through the reversing device 4, so that the phenomenon that the reversing device 4 draws an arc when reversing switching is carried out is avoided, the phenomenon that the switch is damaged by sparks generated after the arc is drawn is avoided, and the service life of the switch is prolonged.

As shown in fig. 3, a movable rod 24 is slidably connected to the inside of the switch housing 2, the switch knob 3 is connected to the top end of the movable rod 24, and the reversing lever 6 is rotatably disposed on one side of the switch housing 2 and is in contact fit with the switch knob 3.

A return spring 9 is provided at the bottom end of the movable lever 24, and the switch knob 3 can be kept in the sprung state by the return spring 9. In the switch housing 2, there are also provided a brake moving contact 5 and a first contact point 10 and a second contact point 11 for cooperating with the brake moving contact 5. A contact spring 12 is connected between the brake moving contact 5 and the switch shell 2, and the brake moving contact 5 can be kept connected with the first connection point 10 and the second connection point 11 through the contact spring 12, so that the first connection point 10 and the second connection point 11 are kept communicated.

As shown in fig. 4, the brake moving contact 5 of this embodiment sequentially includes, from top to bottom: a first contact 13, a support end 14 and a rake end 15. The support end 14 is positioned in the middle of the brake moving contact 5, is rotatably supported and connected in the switch shell 2 and is electrically connected with the second connecting point 11; the warped tail end 15 is located at one end of the brake moving contact 5 and is warped towards one side. When the brake device 8 is in the closed state, the first contact 13 is in contact with the first contact point 10 to maintain electrical connection.

As shown in fig. 5, a movable rod 24 connected below the switch button 3 of this embodiment is provided with a protrusion 16 at the bottom of the movable rod 24, and when the switch button 3 is pressed downward, the protrusion 16 can contact with the raised tail end 15 of the movable brake contact 5 and abut against the raised tail end 15, so that the first contact 13 of the movable brake contact 5 is raised, and thus is away from the first connection point 10, and the connection state between the first connection point 10 and the second connection point 11 is disconnected.

As shown in fig. 6, when the switch button 3 is kept in the lifted state, the top first contact 13 of the brake moving contact 5 is kept connected with the first connection point 10, and the middle support end 14 of the brake moving contact 5 is kept connected with the second connection point 11, so that the first connection point 10 is connected with the second connection point 11, and in the schematic circuit diagram, the brake device 8 is shown in the closed state.

As shown in fig. 7, when the switch button 3 is pressed downwards, the switch button 3 drives the movable rod 24 to move downwards against the elastic force of the return spring 9, the protrusion 16 at the bottom of the movable rod 24 contacts with the tilting tail end 15 of the brake moving contact 5, so as to drive the first contact point 13 end of the brake moving contact 5 to tilt upwards against the biasing force of the contact spring 12, thereby disconnecting the first connection point 10 from the second connection point 11. In the schematic circuit diagram, the brake device 8 is shown in an off state.

As shown in fig. 13, on the side of the switch knob 3 facing the reversing lever 6, there are two recesses 17 for engagement with the reversing lever 6, for the right side view of the reversing brake apparatus. When the switch knob 3 is pressed downward, it is necessary to first rotate the reversing lever 6 so that the reversing lever 6 slides in one of the two recesses 17, otherwise the switch knob 3 cannot be pressed downward due to the restriction of the reversing lever 6. That is, the schematic circuit diagram shows: the brake device 8 can be disconnected only after the reversing device 4 is switched; in a state where the brake device 8 is off, the switching device 4 cannot be switched.

As shown in fig. 14, on the side of the reversing lever 6 facing the switch knob 3, there is a slider 18 for insertion into the recess 17 of the switch knob 3; a connecting column 19 is arranged in the middle of the reversing rod 6 and is rotationally connected with the switch shell 2 through the connecting column 19; two contact pieces 20 for electrically connecting the commutator are provided at the bottom of the commutator bar 6. The top of the sliding block 18 is arc-shaped, two side edges are inclined surfaces which gradually narrow downwards, and after the reversing rod 6 is reversed and rotated, one side surface of the sliding block 18 is kept vertical so as to be matched with the groove 17 of the switch button 3, so that the sliding block 18 can slide in the groove 17.

Example 2

The embodiment provides a reversing brake device 1, as shown in fig. 8, which includes a housing 2, a switch button 3, a movable rod 24, a reversing device 4 and a brake moving contact 5. The structure is mostly the same as that of the brake apparatus of embodiment 1, and the circuit principle of the brake apparatus is also the same as that of embodiment 1. The difference is that the brake moving contact 5 of the present embodiment is slidably disposed in the switch housing 2.

As shown in fig. 9, the brake moving contact 5 of the present embodiment includes: a first contact 13, a second contact 21 and a connection ring 22. The first contact 13 is positioned at the top of the brake moving contact 5 and is used for being in contact and electrically connected with the first connecting point 10 when the brake device 8 is in a closed state; the second contact 21 is located at the bottom of the brake moving contact 5 and is used for being in contact and electrically connected with the second contact point 11 when the brake device 8 is in a closed state; the connecting ring 22 is connected to the brake moving contact 5 and is used for being connected with the switch button 3.

As shown in fig. 10 and 11, when the switch button 3 is kept in the lifted state, the top first contact 13 of the brake movable contact 5 is kept connected with the first connection point 10, and the bottom second contact 21 of the brake movable contact 5 is kept connected with the second connection point 11, so that the first connection point 10 is connected with the second connection point 11, and the brake device 8 is shown in the closed state in the schematic circuit diagram.

As shown in fig. 12, when the switch button 3 is pressed down, the switch button 3 drives the movable rod 24 to move downward against the elastic force of the return spring 9, the bottom of the movable rod 24 is provided with a connecting block 23, the connecting block 23 is inserted into the connecting ring 22 of the brake movable contact 5, so that when the movable rod 24 moves downward, the brake movable contact 5 can be driven to slide downward against the biasing force of the contact spring 12, so that the first contact 13 and the second contact 21 are separated from the first connection point 10 and the second connection point 11, respectively, and the connection between the first connection point 10 and the second connection point 11 is disconnected. In the schematic circuit diagram, the brake device 8 is shown in an off state.

As shown in fig. 13 and 14, the switch knob 3 and the reversing lever 6 of the present embodiment have the same structure as that of embodiment 1.

Example 3

The present embodiment provides a reverse brake device 1, as shown in fig. 15, including: the brake device comprises a shell 2, a switch button 3, a movable rod 24, a reversing device 4 and a brake moving contact 5. The structure is mostly the same as that of the brake apparatus of embodiments 1 and 2, and the circuit principle of the brake apparatus is also the same as that of embodiments 1 and 2. The brake moving contact 5 of the present embodiment is slidably disposed in the switch housing 2 as in embodiment 2, and the difference is that the shape of the brake moving contact 5 of the present embodiment and other structures matched with the brake moving contact 5 are improved.

As shown in fig. 16, the brake moving contact 5 of the present embodiment includes: a first contact 13, a second contact 21 and a connecting piece 25. The first contact 13 is positioned at the top of the brake moving contact 5 and is used for being in contact and electrically connected with the first connecting point 10 when the brake device 8 is in a closed state; the second contact 21 is located at the bottom of the brake moving contact 5 and is used for being in contact and electrically connected with the second contact point 11 when the brake device 8 is in a closed state; the connecting sheet 25 is bent and connected to the brake moving contact 5 for matching connection with the switch button 3.

As shown in fig. 17, an abutting surface 26 is provided at the bottom of the movable rod 24 connected to the bottom of the switch button 3, and when the switch button 3 is pressed downward, the abutting surface 26 can contact with the connecting piece 25 of the movable brake contact 5 and abut against the movable brake contact 5, so that the movable brake contact 5 slides downward, thereby disconnecting the connection between the first connection point 10 and the second connection point 11.

As shown in fig. 18, when the switch button 3 is kept in the raised state, the top first contact 13 of the brake moving contact 5 is kept connected with the first connection point 10, and the bottom second contact 21 of the brake moving contact 5 is kept connected with the second connection point 11, so that the first connection point 10 and the second connection point 11 are connected, and in the schematic circuit diagram, the brake device 8 is shown in the closed state.

As shown in fig. 19 and 20, when the switch button 3 is pressed downward, the switch button 3 drives the movable rod 24 to move downward against the elastic force of the return spring 9, and the abutting surface 26 at the bottom of the movable rod 24 contacts the connecting piece 25 of the movable brake contact 5, so that when the movable rod 24 moves downward, the movable brake contact 5 can be driven to slide downward against the biasing force of the contact spring 12, so that the first contact 13 and the second contact 21 are separated from the first connection point 10 and the second connection point 11, respectively, and the connection between the first connection point 10 and the second connection point 11 is disconnected. In the schematic circuit diagram, the brake device 8 is shown in an off state.

Example 4

The present embodiment provides a dc electric tool switch, which employs the reversing brake device 1 described in embodiment 1, embodiment 2, or embodiment 3, and the dc electric tool switch is used for an electric tool, specifically, an electric screwdriver, an electric drill, an electric hammer, or the like, and other structures may be the same as those in the prior art, and are not described herein again.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.

Claims (10)

1. The switching-over brake equipment of direct current electric tool switch, its characterized in that includes:

the reversing device (4) is connected between the motor (7) and the direct-current power supply and changes the direction of current entering the motor (7) through switching;

and the brake device (8) is directly connected to two ends of the motor (7) and forms a closed loop with the motor (7) in a closed state.

2. The commutating brake apparatus of claim 1, wherein the brake apparatus (8) comprises:

the switch button (3) is fixedly connected with the top end of the movable rod (24);

a movable rod (24) which is connected in the switch shell (2) in a sliding way;

the brake moving contact (5) is arranged in the switch shell (2) and is linked with the movable rod (24);

the contact spring (12) is connected between the switch shell (2) and the brake moving contact (5) and has a biasing force for keeping the contact point on the brake moving contact (5) to deviate towards the direction of a connection state;

the first connecting point (10) is electrically connected with one end of the motor (7) and is electrically connected with a contact on the brake moving contact (5) when the brake device (8) is in a closed state;

and the second connecting point (11) is electrically connected with the other end of the motor (7) and is electrically connected with the other contact on the brake moving contact (5) in a contact way when the brake device (8) is in a closed state.

3. A commutating brake device according to claim 2 characterized in that when the brake device (8) is in the off-state, a contact of the brake moving contact (5) is electrically connected with one end of the motor (7).

4. A reversing brake device according to claim 3, characterised in that the movable brake contact (5) comprises:

the support end (14) is positioned in the middle of the brake moving contact (5), is supported and connected in the switch shell (2), and is electrically connected with the second connecting point (11);

the tilting tail end (15) is positioned at one end part of the brake moving contact (5) and tilts towards one side;

and the first contact (13) is positioned at the other end of the brake moving contact (5) opposite to the warped tail end (15), and is in contact and electric connection with the first connecting point (10) when the brake device (8) is in a closed state.

5. The reversing brake device according to claim 4, characterized in that the bottom of the movable rod (24) is provided with a projection (16), and when the movable rod (24) is pressed downwards, the projection (16) can abut against the tilting tail end (15) to tilt the first contact (13) so as to leave the first connecting point (10).

6. The reversing brake device according to claim 2, characterized in that the brake movable contact (5) is slidably arranged in the switch housing (2).

7. The reversing brake device according to claim 6, characterized in that the brake movable contact (5) comprises:

the first contact (13) is positioned at the top of the brake moving contact (5) and is in contact and electric connection with the first connecting point (10) when the brake device (8) is in a closed state;

and the second contact (21) is positioned at the bottom of the brake moving contact (5) and is in contact and electric connection with the second connecting point (11) when the brake device (8) is in a closed state.

8. The reversing brake device according to claim 7, characterized in that the brake movable contact (5) further comprises:

the connecting ring (22) is connected to the upper end of the brake moving contact (5), a connecting block (23) inserted in the connecting ring (22) is arranged at the bottom of the movable rod (24), and when the movable rod (24) is pressed downwards, the connecting block (23) can abut against the brake moving contact (5) to enable the brake moving contact (5) to slide downwards, so that the first contact (13) and the second contact (21) are separated from the first connection point (10) and the second connection point (11) respectively.

9. The reversing brake device according to claim 7, characterized in that the brake movable contact (5) further comprises:

the connecting piece (25) is connected to the upper end of the brake moving contact (5), the bottom of the movable rod (24) is provided with an abutting surface used for abutting against the connecting piece (25), and when the movable rod (24) is pressed downwards, the abutting surface can abut against the brake moving contact (5) to enable the brake moving contact (5) to slide downwards, so that the first contact (13) and the second contact (21) leave the first connection point (10) and the second connection point (11) respectively.

10. A dc power tool switch comprising the commutating brake apparatus of any one of claims 1 to 9.