JP4936462B2 - Tightening tool - Google Patents

Description

  The present invention relates to a tightening tool used for tightening work such as screws and bolts.

  Conventionally, as a tightening tool used for tightening fasteners such as screws and bolts, the above-mentioned tightening operation is performed using the rotational force of a built-in motor, and when the fastener is seated, it is automatically Some have an automatic stop function to stop the rotation of the motor. For example, Patent Document 1 includes, as the automatic stop function, a torque detection unit that estimates the tightening torque of the fastener based on the rotation angle of the anvil for each impact, and the tightening torque obtained here exceeds a threshold value. It is described that when it is determined that the user has been seated under a predetermined stop condition, the motor is automatically stopped at that time.

  By the way, these conventional tightening tools are assumed to be used at home or in general work sites. Therefore, it is usual to provide a setting switch on the tool body side so that the operator can freely set the stop condition.

However, when the tightening tool is used in a factory line or the like, a problem in torque management occurs in the configuration in which the setting switch is provided on the tool body side as described above. In other words, in the factory line, etc., it is required that the process conditions are set all at once by the process manager, and it is not preferable for each operator to set it freely. In the configuration provided with the setting switch, there is a risk of changing to an unintended stop condition on the administrator side, which becomes a problem in torque management.
JP 2005-118911 A

  The present invention has been invented in view of the above problems, and it is an object of the present invention to provide a tightening tool that can set a stop condition for stopping a tightening operation only by an administrator, not by an operator. It is what.

In order to solve the above problems, the present invention includes a torque detection means 15 that detects a tightening torque, a control means 31 that stops tightening when the tightening torque reaches a predetermined stop condition, and a condition setting means that sets a stop condition. When the tool body A is in the reception-only mode, the condition setting means can set the stop condition only based on a command transmitted wirelessly from the outside of the tool body A. To do. The mode switching means for switching the tool main body A to the reception-only mode is provided only on the tool main body A side, and the tool main body A is changed only after a predetermined time has elapsed since the last use of the tool main body A. Switch to reception-only mode.

  By doing so, it becomes impossible for the operator to freely set the stop condition in a factory line or the like, and the stop condition can be set only by radio from the process manager side. In addition, since the stop condition cannot be set unless the tool body A is confirmed to be set and the tool body A is shifted to the reception-only mode, the tool body A that is not the target is erroneously stopped. Setting conditions is prevented.

Further, the mode switching means is provided only on the tool body A side, and mode switching is performed directly on the tool body A side instead of wirelessly. Switching to the mode is prevented. Furthermore, since the mode switching means enables the tool body A to be switched to the reception-only mode only after a predetermined time has elapsed since the last use of the tool body A, the mode switching means is once separated from the on-site tightening operation. The transition to the reception-only mode is performed.

  In the invention according to claim 1, when the tool body is in the reception-only mode, the stop condition can be set only based on a command transmitted wirelessly from the outside of the tool body. There is an effect that it can be made only by the manager, not the operator. In addition, there is an effect that it is possible to prevent erroneous setting of stop conditions for other tool bodies that are not the target.

In addition, the invention according to claim 1 is effective to prevent other tool bodies that are not the object from being erroneously switched to the reception-only mode, and to the reception-only mode only in a situation once separated from the on-site tightening operation. Therefore, it is possible to more reliably prevent a situation where the mode is switched to the reception-only mode due to an erroneous operation such as during work.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings. FIG. 1 shows a tool main body A of an example tightening tool according to an embodiment of the present invention, and a remote controller B separate from the tool main body A.

  The tool body A of this example is configured as schematically shown in FIG. 2, and when the tightening torque is increased, the hammer 4 repeatedly strikes the anvil 5, and the strong tightening torque generated by this striking causes the screws and It is an impact tool that can reliably perform a tightening operation of a fastener (not shown) such as a bolt.

  In the main body housing 50 that forms the outer shell of the tool main body A, there are provided a motor 1 that is a drive source and a power transmission means 10 that transmits the rotational force of the motor 1 and performs a fastening operation of the fastener. Specifically, the power transmission means 10 includes a speed reducer 2 that transmits the rotation of the motor 1, a drive shaft 3 that is rotationally driven by the motor 1 via the speed reducer 2, and a cam mechanism (not shown). A hammer 4 which is slidably fitted in the axial direction through the shaft 4 and rotates together with the hammer 4, an anvil 5 which rotates by engagement with the hammer 4, and a spring which urges the hammer 4 toward the anvil 5 side. And a bit 7 connected to the anvil 5 and transmitting the rotational force to the fastener. And the impact engagement of the rotation direction of the hammer 4 and the anvil 5 is repeatedly performed as a hit | damage by the said cam mechanism.

  The motor 1 is controlled to rotate and stop by a motor control circuit 8, and the motor control circuit 8 receives a rotation or stop command via the motor control unit 30 in accordance with the amount of pulling in the trigger 9. It is output. Further, the tool body A of this example includes a hit detection means 11 for detecting the hammer 4 hitting the anvil 5, a rotation angle detection means 12 for detecting the rotation angle of the anvil 5, and the means 11 and 12. An anvil rotation angle calculation unit 13 that calculates the rotation angle Δr of the anvil 5 for each impact based on the output of the above, and a torque estimation unit that estimates the tightening torque based on the rotation angle Δr obtained from the anvil rotation angle calculation unit 13 14 and the torque detecting means 15 is formed by the above-described components.

  Specifically, a microphone 16 that detects a striking sound generated when the hammer 4 collides with the anvil 5 as a voltage is installed as the striking detection means 11. Further, as the rotation angle detecting means 12, specifically, a rotary encoder 19 comprising a slit disc 17 that rotates integrally with the anvil 5 and a transmissive photo interrupter 18 that detects the rotation angle of the disc 17 is provided. The rotation angle of the anvil 5 is detected as a pulse signal.

  Both the microphone 16 and the rotary encoder 19 are connected to the anvil rotation angle calculation unit 13 via a waveform shaping circuit 20 composed of a bandpass filter and a comparator, and the impact signal detected by the microphone 16 and the rotary encoder 19 are The detected rotation angle signal is subjected to noise processing by the waveform shaping circuit 20 and sent to the anvil rotation angle calculation unit 13.

The anvil rotation angle calculation unit 13 sequentially calculates the rotation angle Δr of the anvil 5 for each impact as described above, and the torque estimation unit 14 sequentially calculates the tightening torque based on the calculation result. The calculation of the tightening torque in the torque estimating unit 14 is an equation obtained from the relationship that the energy given by the hit and the energy consumed by the tightening are approximately equal, T = (J × ω ² ) / (2 × Δr) It is done by using.

  Here, J is the moment of inertia of the anvil 5, and ω is the rotation speed of the anvil 5 at the time of occurrence of the impact. Since the rotational speed ω is obtained from the pulse width of the rotational angle signal detected by the rotary encoder 19, the estimated torque is calculated by inputting the rotational angle Δr of the anvil 5 for each impact in the above formula.

  Note that the impact detection means 11 and the rotation angle detection means 12 constituting the torque detection means 15 may have different forms. Further, as the torque detection means 15, a means for estimating the tightening torque by another procedure may be used, or a means for detecting the actual tightening torque may be used.

  Next, the tightening determination of this example will be described. The tightening determination unit 21 shown in FIG. 2 determines the seating of the fastener using the tightening torque estimated by the torque estimation unit 14, and outputs a stop command for the motor 1 to the motor control circuit 8 when the seating is determined. It is something to be made.

  The specific seating determination method here is as shown in FIG. 3 and is the same as the method described in Patent Document 1. That is, first, based on the tightening torque calculated for each impact by the torque estimation unit 14, a torque fluctuation amount ΔT, which is a rate of change of the tightening torque with respect to the rotation angle (or time change) of the motor 1, is calculated. A torque fluctuation rate ΔΔT, which is a rate of change of the torque fluctuation amount ΔT with respect to the rotation angle (or time change) of the motor 1, is calculated. When the calculated tightening torque exceeds a predetermined threshold value set in advance and the torque fluctuation rate ΔΔT changes from positive to negative, it is determined as seating and the motor control circuit 8 A stop command is output.

  As described above, the predetermined stop condition using the tightening torque is set in the tool body A, and the motor 1 is stopped when the stop condition is satisfied. It is not necessarily limited, and tightening may be stopped by determining seating according to other stop conditions.

  Next, condition setting means for setting the above-mentioned threshold value of the tightening torque (that is, setting a stop condition for stopping the tightening) will be described. As shown in FIG. 2, the control means 31 incorporated in the tightening tool of this example includes the anvil rotation angle calculation unit 13, the torque estimation unit 14, the tightening determination unit 21, the motor control unit 30, and the like described above, and is estimated. When the tightening torque to be reached reaches a predetermined stop condition, the tightening is stopped.

  The control means 31 includes a display unit 22 that displays the current threshold level (in other words, the current tightening strength level) as a number, a wireless reception unit 23 that receives an infrared signal, and a tool body A that will be described later. A changeover switch 24 serving as a mode switching means for switching to the reception-only mode is connected. As the threshold value, those of a plurality of levels are set in advance, and the setting is changed to a higher threshold value as the display level increases, for example, 1, 2, 3,. An operation panel 25 is provided at the lower part of the grip portion of the tool main body A, and the display unit 22, the wireless reception unit 23, and the changeover switch 24 are arranged in the operation panel 25.

  The remote controller B, which is separate from the tool body A, is held by the process manager, and includes an upper button 41 that changes the threshold value to a threshold value that is one level higher, and a tightening torque threshold value that is one level lower. A lower button 42 for changing to a level threshold value, a determination button 43 for finally determining the changed threshold value, a torque setting button 44, a clear button 45, and a wireless transmission unit 46 for transmitting an infrared signal are provided.

  As shown in FIG. 4, the tool body A has a drive mode and a reception-only mode. The drive mode is a mode for the operator to perform a normal tightening operation. The motor 1 is driven by pulling the trigger 9 and the tightening operation is performed according to the procedure shown in FIG. When the trigger 9 is released, the tool body A enters a driving standby state, and when a predetermined time (for example, 5 minutes) elapses in this driving standby state, the power is automatically turned off (see arrow a).

  The shift to the reception-only mode is performed only when the changeover switch 24 is pushed in and the trigger 9 is pulled in while the tool body A is turned off (see arrow b). Thus, the threshold level can be changed only when the tool body A is shifted to the reception-only mode.

  When the administrator presses the torque setting button 44 of the remote controller B after the target tool body A whose threshold value is to be changed is shifted to the reception-only mode, the radio transmitter 46 of the remote controller B transmits the call. The tool body A that has received the infrared signal received by the wireless receiving unit 23 enters a setting standby state and blinks the number displayed on the display unit 22. Note that the command signals from the remote controller B to the tool body A are all transmitted wirelessly by infrared signals, but the description of the infrared signals will be omitted below.

  Next, when the administrator depresses the upper button 41 or the lower button 42 of the remote controller B, the threshold level is changed on the tool main body A side, and the changed content is flashed and displayed on the display unit 22. . By checking the display content of the display unit 22 and confirming that the threshold value is set to a desired level, when the determination button 43 is pressed, the changed threshold value is determined on the tool body A side. If the clear button 45 is pressed before the enter button 43 is pressed, the threshold can be returned to the original level.

  When the setting change is completed, the tool body A is switched to the drive mode by pulling in the trigger 9 while in the reception-only mode (see arrow c). The tool body A also switches to the drive mode when a predetermined time has elapsed since the last setting operation. After switching to the drive mode, the tightening operation can be performed according to a new stop condition using the changed threshold value. At this time, the current threshold level is displayed on the display unit 22 of the tool body A, and the operator can perform work while confirming the changed new threshold level (tightening strength level).

  That is, in the tightening tool of this example, when the tool body A is in the reception-only mode provided separately from the drive mode, and the command from the remote controller B outside the tool body A is transmitted wirelessly. Only the tightening stop condition is changed. Therefore, an operator who does not hold the remote controller B cannot independently change the threshold value, and the setting change operation can be performed only by the administrator side.

  Moreover, since the tool body A whose threshold value is to be changed must first be shifted to the reception-only mode, the setting cannot be changed. Therefore, the tool body A other than the target to be changed receives the infrared ray in error, and the threshold value is changed unexpectedly. This situation is prevented. Therefore, for example, in a factory line, only the tool body A used in a specific line can be shifted to the reception-only mode, and the setting can be changed one by one or all at once, and the tool body A used in another line can be changed. Even if infrared rays are accidentally emitted, erroneous setting due to this is surely prevented.

  Further, the mode switching means for switching the tool body A to the reception-only mode is installed only in the tool body A side in the form of a combination of the changeover switch 24 and the trigger 9, so that the threshold change target is changed. Only the tool body A can be reliably shifted to the reception-only mode. That is, if the mode switching means is provided on the remote controller B side and switched wirelessly, if the tool body A other than the target erroneously receives a wireless signal, it shifts to the reception-only mode. According to the mode switching means, there is no erroneous reception, and this situation is surely prevented.

  Furthermore, the selector switch 24 and the trigger 9 that are simultaneously operated here are installed on different surfaces in the tool body A so that they cannot be operated simultaneously with one hand, and the operation directions of each other are also set. It is different. Therefore, unless both the switches 24 and 9 are intentionally operated with both hands, the mode cannot be switched to the reception-only mode, and it is prevented that the mode switching is performed excessively.

  Further, in order to more reliably prevent the mode switching from being performed, the power is turned off after a predetermined time has elapsed since the last operation of the trigger 9 of the tool body A, as described above. It is set so that the drive mode can be switched to the reception-only mode only in the state where As a result, the mode can be switched only under conditions where it is once away from the on-site tightening work on the factory line, etc., and the situation where the mode is switched to the reception-only mode due to an erroneous operation during the work is further prevented. ing.

It is explanatory drawing which shows the tool main body and remote control device of an example tightening tool in embodiment of this invention. It is a block diagram of a tool main body same as the above. It is a flowchart which shows the motor stop process of a tool main body same as the above. It is explanatory drawing which shows each mode transition of a tool main body same as the above.

Explanation of symbols

15 Torque detection means 31 Control means A Tool body

Claims (1)

In the tightening tool comprising torque detecting means for detecting the tightening torque, control means for stopping the tightening when the tightening torque reaches a predetermined stop condition, and a condition setting means for setting the stop condition, the condition setting means includes: When the tool body is in the receive-only mode, the stop condition can be set only based on a command transmitted wirelessly from the outside of the tool body, and mode switching means for switching the tool body to the receive-only mode The clamping tool is provided only on the tool body side, and the tool body can be switched to the reception-only mode only after a predetermined time has elapsed since the last use of the tool body .

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