Power tool reverse torque suppression device
Patent Information
- Application Number
- TW114114034
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2026-10-16
- Estimated Expiration
- 2045-04-13
AI Technical Summary
Traditional power tools without a clutch mechanism cause user discomfort and fatigue due to high reaction forces during workpiece locking, as the spindle's rotational inertia requires additional hand force to stop the tool.
A reverse torque suppression device with a transmission unit, magnetic force generating unit, and driven unit that uses magnetic forces to restrict spindle rotation when a set torque is reached, reducing user discomfort by engaging a positioning part to stop the spindle.
The device effectively reduces user hand strain by stopping spindle rotation at high torque levels, alleviating discomfort and fatigue through magnetic engagement and disengagement mechanisms.
Smart Images
Figure TWG2TA001080372_001 
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Figure TWG2TA001080372_003
Abstract
Description
[Technical Field]
[0001] This invention relates to power tool technology; in particular, it refers to a reverse torque suppression device for power tools. [Previous Technology]
[0002] Traditional power tools, such as electric torque screwdrivers or electric torque wrenches without a clutch mechanism, allow the user to set the torque and tighten screws, nuts, and other workpieces according to the user-set torque. When the tightening torque reaches the user-set torque, the motor of the power tool immediately stops rotating. In this way, the workpiece can be tightened to the user-set torque.
[0003] However, during the process of locking the workpiece, the user's hand must exert force to resist the rotational force generated by the power tool in order to maintain the stability of holding the power tool. However, the higher the torque of locking the workpiece, the greater the reaction force on the user's hand. When the power tool locks the workpiece, the motor of the power tool stops transmission. Since there is no clutch mechanism between the motor and the spindle, the motor cannot drive the spindle of the power tool to stop rotating, so that the spindle has a certain rotational inertia. As a result, the power tool cannot absorb the rotational force in time when locking the workpiece, which requires the user to exert additional force to control the power tool. Prolonged use can easily cause wrist discomfort or fatigue for the user.
[0004] Therefore, the design of traditional power tools is still not perfect and there are still areas for improvement. [Summary of the Invention]
[0005] In view of this, the object of the present invention is to provide a reverse torque suppression device for power tools, which can reduce the discomfort experienced by the user when using power tools to lock workpieces.
[0006] In order to achieve the above objectives, the electric tool reverse torque suppression device provided by the present invention includes a transmission unit, a magnetic force generating unit and a driven unit. The transmission unit has a main shaft with a slide rail section. A magnetic force generating unit passes through the main shaft, and the main shaft rotates relative to the magnetic force generating unit. The magnetic force generating unit has a stop surface with a first positioning part. A driven unit is sleeved on the slide rail section of the main shaft and faces the stop surface of the magnetic force generating unit. The driven unit can be driven to rotate by the main shaft. The driven unit moves relative to the magnetic force generating unit along the direction of the main shaft between a first position and a second position. The driven unit has a second positioning part that engages with the first positioning part. When the driven unit is in the first position, the second positioning part disengages from the first positioning part. When the magnetic force generating unit generates an attractive magnetic force, the magnetic force generating unit drives the driven unit to move towards the stop surface and be in the second position. The second positioning part engages with the first positioning part, thereby restricting the rotation of the main shaft.
[0007] The effect of the present invention is that when the power tool is locking or disassembling a workpiece, the driven unit is located in the first position and can be driven to rotate by the spindle. When the power tool encounters a torque increase that reaches the set torque, the transmission unit stops transmission. At this time, the magnetic force generating unit can generate an attractive magnetic force to drive the driven unit. The driven unit moves from the first position to the second position, so that the second positioning part engages with the first positioning part. The driven unit restricts the rotation of the spindle and stops the rotation of the spindle, which can effectively reduce the discomfort caused by the reaction force to the user's hand in the high torque stage.
Implementation Method
[0008] To more clearly illustrate the present invention, preferred embodiments are described in detail below with reference to the accompanying drawings. Please refer to Figures 1, 2 and 5, which show a power tool reverse torque suppression device 100 provided in the first preferred embodiment of the present invention, for installation inside a tool housing 1. The power tool reverse torque suppression device 100 includes a transmission unit 10, a magnetic force generating unit 20 and a driven unit 30.
[0009] The transmission unit 10 has a motor 11 and a spindle 12. The motor 11 is fixed to the tool housing 1 and drives the spindle 12 to rotate, as shown in Figures 2 and 5. The motor 11 has a gearbox 111 connected to the spindle 12. The spindle 12 has a slide rail section 121, a first smooth section 122, and a second smooth section 123. A plurality of sliders 1211 are surrounded on the slide rail section 121. The sliders 1211 move along the slide rail section 121. The main shaft 12 is oriented in the direction of the slide rail section 121. The first smooth section 122 and the second smooth section 123 are located on both sides of the slide rail section 121. The first smooth section 122 and the second smooth section 123 are the flat surfaces of the main shaft 12. The gearbox 111 is pivotally connected to the first smooth section 122. The motor 11 drives the main shaft 12 to rotate through the gearbox 111. The main shaft 12 is provided with a retaining ring 13, which is fixed to the second smooth section 123 and close to the slide rail section 121.
[0010] The magnetic force generating unit 20 passes through the main shaft 12 of the transmission unit 10. In the first embodiment, the magnetic force generating unit 20 passes through the first smooth section 122 of the main shaft 12, and the magnetic force generating unit 20 is fixed to the tool housing 1, so that the main shaft 12 rotates relative to the magnetic force generating unit 20. As shown in Figures 2 and 5, the magnetic force generating unit 20 includes an electromagnetic coil module 21, a cover plate 22, and a first positioning part 23. The electromagnetic coil module 21 is connected to a controller (not shown in the figure), which can control the electromagnetic coil module. Group 21 generates an attractive magnetic force and a repulsive magnetic force. The electromagnetic coil module 21 has a plurality of slots 211 and a plurality of electromagnetic coils 212. The slots 211 are arranged around the main shaft 12, with their openings facing the slide rail section 121 of the main shaft 12. The electromagnetic coils 212 are arranged along the direction of the main shaft 12 and are arranged around the main shaft 12. The two ends of each electromagnetic coil 212 are exposed on both sides of the electromagnetic coil module 21. The electromagnetic coils 212 can be connected in series or in parallel. 2. The attractive and repulsive magnetic forces can be controlled to be generated. The cover plate 22 is attached to one side of the electromagnetic coil module 21. The cover plate 22 has a stop surface 221 facing the slide rail section 121 of the main shaft 12, as shown in Figures 3 and 5. The stop surface 221 has a plurality of through holes 222 and a plurality of electromagnetic openings 223. The through holes 222 correspond to the positions of the equal-accommodation grooves 211, and the electromagnetic openings 223 correspond to the positions of the equal electromagnetic coils 212, so that one end of the equal electromagnetic coils 212 is exposed on the stop surface 221. The magnetic opening 223 is not blocked by the cover plate 22. The first positioning part 23 is disposed between the electromagnetic coil module 21 and the cover plate 22. In the first embodiment, the first positioning part 23 includes a plurality of protrusions 231 and a plurality of springs 232. The protrusions 231 and the springs 232 are respectively accommodated in the receiving grooves 211. The protrusions 231 are pushed out of the through holes 222 by the springs 232, so that the protrusions 231 normally protrude from the stop surface 221 of the cover plate 22, and the protrusions 231 can elastically retract into the stop surface 221 when pressed.
[0011] In other embodiments, the structure of the magnetic force generating unit 20 can be adjusted as needed. For example, the cover plate 22 can be omitted from the magnetic force generating unit 20, and the springs 232 can be omitted from the first positioning part 23. That is to say, the magnetic force generating unit 20 only needs to have the stop surface 221, and the protrusions 231 of the first positioning part 23 can be fixedly disposed on the stop surface 221.
[0012] The driven unit 30 is sleeved on the slide rail section 121 of the main shaft 12, and the driven unit 30 faces the stop surface 221 of the cover plate 22. The magnetic force generating unit 20 is located between the motor 11 and the driven unit 30. The driven unit 30 can be driven to rotate by the main shaft 12. The driven unit 30 moves relative to the magnetic force generating unit 20 along the direction of the main shaft 12 between a first position P1 and a second position P2. The driven unit 30 is blocked by the magnetic force generating unit 20 and the retaining ring 13 and will not disengage from the slide rail section 121 of the main shaft 12. In the first embodiment, as shown in Figures 2, 4 and 5, the driven unit 30 includes a metal plate 31, a magnet 32 and a second positioning part 33. The metal plate 31 is sleeved on the slide rail section 121 of the main shaft 12, and the metal plate 31 can be driven by the magnetic attraction force of the magnetic force generating unit 20 to move towards it. The stop surface 221 of the cover plate 22 has a metal plate 31 with a shaft hole 311. The inner edge of the shaft hole 311 is provided with a plurality of grooves 312 that correspond to the sliders 1211 of the slide rail section 121. The magnet 32 and the second positioning part 33 are respectively disposed on the metal plate 31. The magnet 32 can be attracted and repelled by the electromagnetic coil module 21, so that the metal plate 31 can be displaced between the first position P1 and the second position P2. The second positioning part 33 is engaged with the first positioning part 23. The second positioning part 33 is a plurality of limiting grooves 331. The limiting grooves 331 surround the shaft hole 311. The positions of the limiting grooves 331 correspond to the protrusions 231, but are not limited thereto. In other embodiments, the forms of the first positioning part 23 and the second positioning part 33 can be interchanged, as long as the first positioning part 23 and the second positioning part 33 can engage with each other.
[0013] As shown in Figure 5, during the actual locking or disassembly operation of the power tool reverse torque suppression device 100, the driven unit 30 is initially located at the first position P1. There is a gap between the metal plate 31 of the driven unit 30 and the cover plate 22 of the magnetic force generating unit 20, and the second positioning part 33 of the driven unit 30 is disengaged from the first positioning part 23 of the magnetic force generating unit 20. The motor 11 of the transmission unit 10 can drive the spindle 12 to rotate relative to the magnetic force generating unit 20, and the metal plate 31 of the driven unit 30 rotates with the spindle 12.
[0014] As shown in Figure 6, when the reverse torque suppression device 100 of the power tool encounters an increase in torque reaching the set torque, the electromagnetic coils 212 of the electromagnetic coil module 21 are controlled to generate the attracting magnetic force. The metal plate 31 and the magnet 32 of the driven unit 30 are attracted by the electromagnetic coil module 21, causing the metal plate 31 to be driven upward by the electromagnetic coil module 21 and move towards the stop surface 221 of the cover plate 22. The driven unit 30 moves from the first position P1 to the second position P2. At least one protrusion 231 of the first positioning part 23 can be inserted into one of the limiting grooves 331 of the second positioning part 33, so that the second positioning part 33 and the first positioning part 23 are engaged. The second positioning part 33 of the driven unit 30 is limited by the first positioning part 23 of the magnetic force generating unit 20 and stops rotating. The driven unit 30 correspondingly restricts the rotation of the main shaft 12, thereby counteracting the rotational force of the main shaft 12. This can effectively reduce the discomfort caused by the reaction force to the user's hand during the high torque stage.
[0015] In addition, when the reverse torque suppression device 100 of the power tool needs to resume the operation of the transmission unit 10, the electromagnetic coil module 21 can switch from the attractive magnetic force to the repulsive magnetic force. The magnet 32 of the driven unit 30 is pushed back by the repulsive magnetic force of the electromagnetic coil module 21, so that the magnet 32 moves the metal plate 31 away from the cover plate 22. The driven unit 30 is reset from the second position P2 to the first position P1, releasing the restriction relationship between the first positioning part 23 and the second positioning part 33, thereby restoring the transmission operation of the transmission unit 10.
[0016] It is worth noting that the action of the driven unit 30 resetting from the second position P2 to the first position P1 is not limited to being achieved by generating the repulsive magnetic force by the electromagnetic coil module 21. For example, please refer to FIG7, which is a power tool reverse torque suppression device 100' provided in the second preferred embodiment of the present invention, including the aforementioned transmission unit 10, the aforementioned magnetic force generating unit 20 and the aforementioned driven unit 30. The structural description of the transmission unit 10, the magnetic force generating unit 20 and the driven unit 30 in the second embodiment is substantially the same as that in the first embodiment. In the second embodiment, the driven unit 30 replaces the magnet. An elastic element 34, which is a tension spring, is provided. The two ends of the elastic element 34 are connected to the metal plate 31 and the retaining ring 13. The metal plate 31 of the driven unit 30 is held in the first position P1 by the tension of the elastic element 34. When the driven unit 30 is in the second position P2, the elastic element 34 continues to pull the metal plate 31. When the electromagnetic coil module 21 closes the attraction magnetic force, the metal plate 31 is pulled away from the stop surface 221 of the cover plate 22 by the tension of the elastic element 34, thus completing the action of the driven unit 30 resetting from the second position P2 to the first position P1.
[0017] In addition, please refer to Figures 8 to 11, which are the electric tool reverse torque suppression device 200 provided in the third preferred embodiment of the present invention, including a transmission unit 40, a magnetic force generating unit 50 and a driven unit 60.
[0018] The transmission unit 40 has a motor 41 and a main shaft 42. The motor 41 is used to drive the main shaft 42 to rotate. As shown in FIG9, the motor 41 has a gearbox 411 connected to the main shaft 42. The main shaft 42 has a slide rail section 421, a first smooth section 422 and a second smooth section 423. The slide rail section 421 has a plurality of sliders 4211 surrounding the main shaft 42. The first smooth section 422 and the second smooth section 423 are located on both sides of the slide rail section 421. The gearbox 411 is pivotally connected to the first smooth section 422. The main shaft 42 is provided with a retaining ring 43. The retaining ring 43 is fixed to the first smooth section 422 and close to the motor 41.
[0019] The magnetic force generating unit 50 passes through the main shaft 42 of the transmission unit 40. The structure of the magnetic force generating unit 50 in the third embodiment is substantially the same as that of the magnetic force generating unit 20 in the first embodiment. In the third embodiment, the magnetic force generating unit 50 passes through the second smooth section 423 of the main shaft 42, and the magnetic force generating unit 50 is fixed to a machine tool housing (not shown in the figure). The main shaft 42 rotates relative to the magnetic force generating unit 50, as shown in Figures 9 and 10. The magnetic force generating unit 50 includes an electromagnetic coil module 51, a cover plate 52, and a first positioning part 53. The electromagnetic coil module 51 has a plurality of electromagnetic coils 511. The electromagnetic coils 511 can generate an attractive magnetic force. The cover plate 52 is attached to one side of the electromagnetic coil module 51. The cover plate 52 has a stop surface 521 facing the motor 41. A plurality of electromagnetic openings 522 are passed through the stop surface 521. The electromagnetic openings 522 correspond to the positions of the electromagnetic coils 511, so that one end of the electromagnetic coils 511 is exposed in the electromagnetic openings 522 of the stop surface 521 and is not blocked by the cover plate 52. The first positioning part 53 is disposed between the electromagnetic coil module 51 and the cover plate 52. The first positioning part 53 includes a plurality of protrusions 531, which protrude from the stop surface 521 of the cover plate 52.
[0020] The driven unit 60 is sleeved on the slide rail section 421 of the main shaft 42. The driven unit 60 faces the stop surface 521 of the cover plate 52 and is located between the motor 41 and the magnetic force generating unit 50. The driven unit 60 can be driven to rotate by the main shaft 42. The driven unit 60 moves relative to the magnetic force generating unit 50 along the direction of the main shaft 42 between a first position P1' and a second position P2'. The structure of the driven unit 60 in the third embodiment is substantially the same as that of the driven unit 30 in the second embodiment. In the third embodiment, as shown in Figures 9 and 10, the driven unit 60 includes a metal plate 61, a second positioning part 63, and an elastic member 64. The metal plate 61 is sleeved on the main shaft. On the slide rail section 421 of 42, the second positioning part 63 is disposed on the metal plate 61. The second positioning part 63 is engaged with the first positioning part 53. The second positioning part 63 is a plurality of limiting grooves 631, and the positions of the limiting grooves 631 correspond to the protrusions 531. The two ends of the elastic member 64 are connected to the metal plate 61 and the retaining ring 43. The metal plate 61 is held at the first position P1' by the tension of the elastic member 64. At this time, there is a gap between the metal plate 61 of the driven unit 60 and the cover plate 52 of the magnetic force generating unit 50, and the second positioning part 63 of the driven unit 60 is disengaged from the first positioning part 53 of the magnetic force generating unit 50, so that the motor 41 of the transmission unit 40 can drive the main shaft 42 to rotate.
[0021] As shown in Figures 9 and 11, when the reverse torque suppression device 200 of the power tool encounters a torque increase that reaches the set torque, the electromagnetic coil module 51 is controlled to generate the attraction magnetic force. The metal plate 61 can be driven by the electromagnetic coil module 51 to move downward toward the stop surface 521 of the cover plate 52, and the driven unit 60 moves from the first position P1' to the second position P2'. The protrusion 531 of the first positioning part 53 can be inserted into the limiting groove 631 of the second positioning part 63, so that the second positioning part 63 and the first positioning part 53 are engaged. In this way, the driven unit 60 restricts the rotation of the spindle 42, and also reduces the discomfort caused to the user's hand by the reaction force.
[0022] Furthermore, when the power tool reverse torque suppression device 200 needs to restore the operation of the transmission unit 40, it is only necessary to turn off the attractive magnetic force of the electromagnetic coil module 51. The metal plate 61 is pulled away from the stop surface 521 of the cover plate 52 by the elastic member 64, and the driven unit 60 is reset from the second position P2' to the first position P1', releasing the restrictive relationship between the first positioning part 53 and the second positioning part 63, thereby restoring the transmission operation of the transmission unit 40. In this embodiment, the driven unit 60 omits the elastic element 64 and replaces it with a magnet. The magnet is disposed on the metal plate 61. The electromagnetic coil module 51 can generate a repulsive magnetic force. When the electromagnetic coil module 51 switches from the attractive magnetic force to the repulsive magnetic force, the magnet of the driven unit 60 is pushed back by the repulsive magnetic force of the electromagnetic coil module 51. The magnet moves the metal plate 61 away from the cover plate 52, thus completing the action of the driven unit 60 returning to the first position P1'.
[0023] As described above, when a power tool encounters a torque increase reaching the set torque during the process of locking or disassembling a workpiece, the reverse torque suppression device 100, 200 drives the driven unit 30, 60 from the first position P1, P1' to the second position P2, P2' via the magnetic force generating unit 20, 50. The second positioning part 33, 63 engages with the first positioning part 23, 53, stopping the rotation of the spindle 12, 42, which can effectively reduce the user's hand strain at high torque levels. The discomfort caused by the reaction force can be relieved when the reverse torque suppression device 100, 200 of the power tool needs to restore the operation of the transmission unit 10, 40. The driven unit 30, 60 can be controlled to move away from the magnetic force generating unit 20, 50, thereby releasing the restriction relationship between the first positioning part 23, 53 and the second positioning part 33, 63. In other words, the driven unit 30, 60 can be reset from the second position P2, P2' to the first position P1, P1', and the transmission operation of the transmission unit 10, 40 can be restored.
[0024] The above description is only a preferred embodiment of the present invention. Any equivalent changes made by applying the present invention specification and the claims should be included within the patent scope of the present invention. [Simplified Explanation of the Diagram]
[0025] Figure 1 is a perspective view of the reverse torque suppression device for an electric tool according to a first preferred embodiment of the present invention. Figure 2 is an exploded structural view of the reverse torque suppression device for an electric tool according to a first preferred embodiment of the present invention. Figure 3 is a plan view of the cover plate of the magnetic force generating unit according to a first preferred embodiment of the present invention. Figure 4 is a plan view of the metal plate of the driven unit according to a first preferred embodiment of the present invention. Figure 5 is a schematic diagram of the driven unit in the first position according to a first preferred embodiment of the present invention. Figure 6 is an operational diagram of the driven unit in the second position according to a first preferred embodiment of the present invention. Figure 7 is a structural diagram of the reverse torque suppression device for an electric tool according to a second preferred embodiment of the present invention. Figure 8 is a perspective view of the reverse torque suppression device for an electric tool according to a third preferred embodiment of the present invention. Figure 9 is an exploded structural view of the reverse torque suppression device for an electric tool according to a third preferred embodiment of the present invention. Figure 10 is a side view of the driven unit in the first position according to a third preferred embodiment of the present invention. Figure 11 is a side view of the driven unit in the second position according to a third preferred embodiment of the present invention.
Claims
1. A reverse torque suppression device for power tools, comprising: A transmission unit has a main shaft with a slide rail section on the main shaft; A magnetic force generating unit is inserted through the main shaft, the main shaft rotates relative to the magnetic force generating unit, the magnetic force generating unit has a stop surface, and the stop surface is provided with a first positioning part; A driven unit is sleeved on the slide rail section of the main shaft and faces the stop surface of the magnetic force generating unit. The driven unit can be driven to rotate by the main shaft. The driven unit moves relative to the magnetic force generating unit along the direction of the main shaft between a first position and a second position. The driven unit includes a second positioning part. When the driven unit is in the first position, the second positioning part is disengaged from the first positioning part. When the magnetic force generating unit generates an attractive magnetic force, the magnetic force generating unit drives the driven unit to move towards the stop surface and be in the second position. The second positioning part engages with the first positioning part, and the driven unit restricts the rotation of the main shaft. The magnetic force generating unit can switch to a repulsive magnetic force. The driven unit includes a metal plate and a magnet. The metal plate is sleeved on the slide rail section and can be driven by the attractive magnetic force of the magnetic force generating unit to move towards the stop surface. The magnet and the second positioning part are disposed on the metal plate. When the magnetic force generating unit switches from the attractive magnetic force to the repulsive magnetic force, the magnet of the driven unit is pushed by the repulsive magnetic force of the magnetic force generating unit, and the driven unit is reset from the second position to the first position.
2. A reverse torque suppression device for power tools, comprising: A transmission unit has a main shaft with a slide rail section on the main shaft; A magnetic force generating unit is inserted through the main shaft, the main shaft rotates relative to the magnetic force generating unit, the magnetic force generating unit has a stop surface, and the stop surface is provided with a first positioning part; The system includes a driven unit fitted onto the slide rail section of the main shaft and facing the stop surface of the magnetic force generating unit. The driven unit can be driven to rotate by the main shaft. The driven unit moves relative to the magnetic force generating unit along the direction of the main shaft between a first position and a second position. The driven unit includes a second positioning part. When the driven unit is in the first position, the second positioning part disengages from the first positioning part. When the magnetic force generating unit generates an attractive magnetic force, the magnetic force generating unit drives the driven unit to move towards the stop surface and be in the second position. The second positioning part engages with the first positioning part, thereby restricting the rotation of the main shaft. The transmission unit includes a motor that drives the main shaft to rotate. The main shaft has a first smooth section and a second smooth section, which are located on both sides of the slide rail section. The motor is pivotally connected to the first smooth section, and the magnetic force generating unit passes through the first smooth section and is located between the motor and the driven unit.
3. The reverse torque suppression device for power tools as described in claim 2, wherein the spindle is provided with a retaining ring, the retaining ring is fixed to the second smooth section, the driven unit includes a metal plate and an elastic member, the metal plate is sleeved on the slide rail section and can be driven by the attraction magnetic force of the magnetic force generating unit to move towards the stop surface, the second positioning part is provided on the metal plate, the two ends of the elastic member are connected to the metal plate and the retaining ring, when the magnetic force generating unit closes the attraction magnetic force, the metal plate is pulled away from the stop surface by the elastic member, and the driven unit is reset from the second position to the first position.
4. A reverse torque suppression device for power tools, comprising: A transmission unit has a main shaft with a slide rail section on the main shaft; A magnetic force generating unit is inserted through the main shaft, the main shaft rotates relative to the magnetic force generating unit, the magnetic force generating unit has a stop surface, and the stop surface is provided with a first positioning part; The system includes a driven unit fitted onto the slide rail section of the main shaft and facing the stop surface of the magnetic force generating unit. The driven unit can be driven to rotate by the main shaft. The driven unit moves relative to the magnetic force generating unit along the direction of the main shaft between a first position and a second position. The driven unit includes a second positioning part. When the driven unit is in the first position, the second positioning part disengages from the first positioning part. When the magnetic force generating unit generates an attractive magnetic force, the magnetic force generating unit drives the driven unit to approach the stop surface and be in the second position. The second positioning part engages with the first positioning part, thereby restricting the rotation of the main shaft. The transmission unit includes a motor that drives the main shaft to rotate. The main shaft has a first smooth section and a second smooth section, which are located on both sides of the slide rail section. The motor is pivotally connected to the first smooth section, the magnetic force generating unit passes through the second smooth section, and the driven unit is located between the motor and the magnetic force generating unit.
5. The reverse torque suppression device for power tools as described in claim 4, wherein the spindle is provided with a retaining ring, the retaining ring is fixed to the first smooth section, the driven unit includes a metal plate and an elastic member, the metal plate is sleeved on the slide rail section and can be driven by the attraction magnetic force of the magnetic force generating unit to move towards the stop surface, the second positioning part is provided on the metal plate, the two ends of the elastic member are connected to the metal plate and the retaining ring, when the magnetic force generating unit closes the attraction magnetic force, the metal plate is pulled away from the stop surface by the elastic member, and the driven unit is reset from the second position to the first position.
6. A reverse torque suppression device for power tools, comprising: A transmission unit has a main shaft with a slide rail section on the main shaft; A magnetic force generating unit is inserted through the main shaft, the main shaft rotates relative to the magnetic force generating unit, the magnetic force generating unit has a stop surface, and the stop surface is provided with a first positioning part; A driven unit is sleeved on the slide rail section of the main shaft and faces the stop surface of the magnetic force generating unit. The driven unit can be driven to rotate by the main shaft. The driven unit moves relative to the magnetic force generating unit along the direction of the main shaft between a first position and a second position. The driven unit includes a second positioning part. When the driven unit is in the first position, the second positioning part disengages from the first positioning part. When the magnetic force generating unit generates an attractive magnetic force, the magnetic force generating unit drives the driven unit to approach the stop surface and be in the second position. The second positioning part engages with the first positioning part, and the driven unit restricts the rotation of the main shaft. The first positioning part has a plurality of protrusions that protrude from the stop surface. The second positioning part has a plurality of limiting grooves. When the driven unit is in the second position, at least one protrusion is inserted into one of the limiting grooves.
7. The reverse torque suppression device for power tools as claimed in claim 6, wherein the magnetic force generating unit has an electromagnetic coil module and a cover plate, the electromagnetic coil module has a plurality of receiving slots, the first positioning part has a plurality of springs, the springs and the protrusions are respectively received in the receiving slots, the cover plate is coupled to one side of the electromagnetic coil module and closes the receiving slots, the cover plate has a stop surface, the stop surface is provided with a plurality of through holes corresponding to the positions of the receiving slots, and the protrusions are pushed out of the through holes by the springs.