Screw fastening counting system

Abstract

To provide a screw fastening counting system capable of preventing counting errors of screw fastening and contributing to improvement in productivity.SOLUTION: A screw fastening counting system has a screw feeder 2, an electric driver 3, and a count display device 4 displaying a screw fastening number. In the screw feeder 2, a guide member 2a of a screw to be taken out is formed by a conductive member. The count display device 4 has: a conductivity determination circuit 44a for generating a pickup signal when the guide member 2a and a bit 3a of the electric driver 3 are brought into an electrically conductive state; a torque-up signal input part 44b for inputting a torque-up signal outputted by the electric driver 3; and a display part 41 for displaying the number whose screw fastening is determined to be completed. A count display device CPU 45 determines screw fastening completion on the basis of both a pickup signal and a torque-up signal and, when the torque-up signal is detected in the state that the conductivity determination circuit 44a generates the pickup signal, determines screw fastening is completed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a screw tightening counting system for preventing failure to tighten a screw when a power screwdriver is used to tighten a circuit board or the like. [Background technology]

[0002] Conventionally, there have been systems that prevent screws from being left unfastened. For example, Patent Document 1 has an electric screwdriver that outputs a torque-up signal when a set torque value is reached, and a work result display device that displays the number of screws that have been fastened. The work result display device determines whether screws have been fastened and displays the number of screws that have been fastened based on the torque-up signal output from the electric screwdriver and the motor rotation signal. This display allows the user to see at a glance how many screws have been fastened, making it possible to check for missed screws. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-189837 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 above determines completion of screw tightening from both the screw tightening time and the torque-up signal, so that even if the same screw is tightened twice for confirmation, it is possible to prevent the system from determining that two screws are complete. This was because if the torque-up signal was output within the reference time, it was determined that the screw had not been tightened correctly, but it was not possible to eliminate the problem of determining that the screw had been tightened multiple times when the same screw was tightened multiple times due to a defect in the screw hole or the screw being inserted at an angle, etc. As a result, even if a screw was left untightened, the displayed screw tightening count number would reach the required number, and the problem of productivity decreasing because the missed tightening could not be recognized continued.

[0005] In view of the above problems, the present invention aims to provide a screw tightening counting system that can prevent mistakes in counting screw tightening and contribute to improving productivity. [Means for solving the problem]

[0006] In order to solve the above problems, the screw tightening count system of the present invention comprises a screw providing means, an electric screwdriver, and a count display device that displays the number of screws tightened, the screw providing means having a storage portion for the screw to be taken out formed of a conductive material, the count display device having a pickup detection portion that generates a pickup signal when the storage portion and the bit of the electric screwdriver become electrically conductive, a torque up signal input portion that inputs a torque up signal output by the electric screwdriver, a screw tightening judgment portion that judges that the screws have been tightened completely, and a display portion that displays the number of screws that have been tightened completely, and the screw tightening judgment portion judges that the screws have been tightened completely when it detects the torque up signal while the pickup detection portion has generated the pickup signal. According to this configuration, if it is not detected that the screw providing means and the bit of the electric screwdriver are in a conductive state through the screw, i.e., if the screw is not removed by the electric screwdriver, it is not determined that the screw has been tightened even if a torque-up signal is detected. Therefore, even if the same screw is tightened multiple times, the screw tightening count does not increase, and even if the pickup signal is detected multiple times, the screw tightening is not counted unless a torque-up signal is generated. This prevents mistakes in counting the screw tightening, which contributes to improving productivity.

[0007] Another aspect of the present invention is a screw supplying device having the above configuration, wherein the screw providing means has a mechanism for sequentially sending screws to the storage section each time a screw is taken out by the electric screwdriver, and the pick-up detection section generates a pick-up signal when a guide member forming part of the storage section and the bit of the electric screwdriver become electrically conductive. According to this configuration, even if a screw feeder is used, the pickup signal is generated when the guide member of the screw feeder and the bit are brought into a conductive state, so that the pickup signal can be generated with a simple configuration. Effect of the Invention

[0008] According to the present invention, if it is not detected that the screw providing means and the bit of the electric screwdriver are in a conductive state through the screw, i.e., if the electric screwdriver does not take out the screw, it is not determined that the screw has been tightened completely even if a torque-up signal is detected. Therefore, even if the same screw is tightened multiple times, the screw tightening count does not increase, and even if the pickup signal is detected multiple times, the screw tightening is not counted unless a torque-up signal is generated. This prevents mistakes in counting screw tightening, which contributes to improving productivity. [Brief description of the drawings]

[0009] [Figure 1] 1 is a configuration diagram showing an example of a screw tightening counting system according to the present invention. [Diagram 2] FIG. 2 is a block diagram of a count display device. [Diagram 3] FIG. 11 is a configuration diagram showing another example of a screw tightening counting system. [Figure 4] 10A and 10B show another embodiment of the count display device, where (a) is a front view and (b) is an explanatory diagram of a unit corresponding to this count display device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a block diagram showing an example of a screw tightening counting system according to the present invention. The screw tightening count system 1 is composed of a screw supplier (screw providing means) 2, an electric screwdriver 3, and a count display device 4. The screw feeder 2 is a device equipped with a mechanism for feeding out screws picked up by the electric screwdriver 3, and a commercially available screw feeder can be used. For example, the Entrust FK-505 can be used. The electric screwdriver 3 is one that outputs a torque-up signal to determine whether the screw has been tightened, and for example, the Nitto Kohki DLV8030 can be used.

[0011] Fig. 2 is a block diagram of the count display device 4. As shown in Fig. 2, the count display device 4 includes a display unit 41 that displays the number of screws fastened, a setting unit (setting switch) 42 that sets the number of completed screws fastening in accordance with the number of screws used for the unit to be fastened, an operation unit 43 (an add button 43a, a subtract button 43b, a reset button 43c) for changing the display, a signal input unit 44, a count display device CPU 45, etc. The display section 41 is configured with three display sections: a total count display section 41a that displays the total number of screws tightened, a unit count display section 41b that displays the number of units that have been screwed tightened, and a shot count display section 41c that displays the current number of screws tightened in the unit. The count display device CPU 45 has a function as a screw tightening determination unit that determines whether a screw has been tightened.

[0012] Three electric wires, a first electric wire L1 to a third electric wire L3, are connected to the signal input unit 44. The first electric wire L1 is connected to a housing M of the screw feeder 2. A guide member 2a constituting a screw storage portion of the screw feeder 2 is made of metal and is screwed into the housing M. As a result, the guide member 2a and the housing M are in an electrically conductive state, and the first electric wire L1 is electrically connected to the guide member 2a. The second electric wire L2 is connected to a metallic holding member N that holds a bit 3a inserted into the tip of the electric screwdriver 3. The bit 3a and the holding member N are in an electrically conductive state, and the second electric wire L2 is electrically connected to the bit 3a. One end of the third electric wire L3 is connected to a torque-up signal output portion (not shown) of the electric screwdriver 3, and the other end is connected to a torque-up signal input portion 44b of the signal input portion 44. The second electric wire L2 is connected to the holding member N by utilizing the magnetic force of a neodymium magnet, for example.

[0013] The signal input unit 44 is equipped with a continuity determination circuit (pickup detection unit) 44a which monitors the electrical resistance between the first electric wire L1 and the second electric wire L2 and determines whether the resistance value between the two has dropped to 0 ohms or close to 0 ohms, resulting in a conductive state. When it is determined that continuity has occurred, a pickup signal is output to the count display device CPU 45.

[0014] The screw tightening counting system configured as above operates as follows. First, the display setting is made according to the unit to be screwed. Here, a case will be described in which four screws are used to attach one unit. Therefore, the setting switch 42 is set to "4." After the setting, the screw tightening operation is started, and when the electric screwdriver 3 is operated to pick up a screw (not shown) from the screw feeder 2, the bit 3a of the electric screwdriver 3 momentarily becomes electrically conductive with the guide member 2a via the screw. The continuity determination circuit 44a recognizes this momentary action and outputs a pickup signal to the count display device CPU 45.

[0015] The count display device CPU 45 receives the pickup signal, sets a flag, and waits for the input of a torque-up signal. In this state, when a torque-up signal is output by the screw tightening operation of the electric screwdriver 3, this signal is input to the count display device 4. When the torque-up signal is input, the count display device CPU 45 determines that screw tightening is complete and resets the flag. Incidentally, if the flag is not set, it is not determined that the screw tightening is complete even if a torque-up signal is received.

[0016] When it is determined that the screw tightening is completed, the count display device CPU 45 updates the display on the display unit 41 by incrementing the display by 1. This display update will be specifically described with reference to FIG. The number displayed in the shot count display section 41c is currently "3", and if it is increased by 1 it will become 4. However, since the set number is 4, the shot count display section 41c is reset to "0". In addition, the unit count display section 41b changes its display from the current "27" to "28" after the shot count display section 41c is reset. Furthermore, the total count display section 41a increments by 1 each time a screw is tightened, changing from the current "111" to "112."

[0017] If the flag is not set even when a torque-up signal is received, it is not determined that screw tightening is complete, and the individual values ​​do not change.

[0018] In this way, if it is not detected that the screw feeder 2 and the bit 3a of the electric screwdriver 3 are in a conductive state via the screw, i.e., if the electric screwdriver 3 does not take out the screw, it is not determined that the screw has been tightened completely even if a torque-up signal is detected. Therefore, even if the same screw is tightened multiple times, the screw tightening count does not increase, and even if the pickup signal is detected multiple times, the screw tightening is not counted unless a torque-up signal is generated. This prevents mistakes in counting screw tightening, which contributes to improving productivity. Furthermore, even if the screw supplier 2 is used, the pickup signal is generated when the guide member 2a and the bit 3a of the screw supplier 2 are brought into a conductive state, so that the pickup signal can be generated with a simple configuration.

[0019] 3 shows another embodiment of the screw tightening counting system 1, which differs from the above embodiment in that it does not use the screw feeder 2. Here, a metal screw aligning plate 5 is used instead of the screw feeder 2, and the first electric wire L1 is connected to the screw aligning plate 5. The screw aligning plate 5, which has a large number of accommodating portions 5a that accommodate the screws 6 arranged in an aligned manner, can be made from a metal member and used in place of the screw feeder 2. When the bit 3a of the electric screwdriver 3 comes into contact with a screw in the screw aligning plate 5, electrical continuity is established between the screw aligning plate 5 and the electric screwdriver 3, and a pickup signal can be generated by detecting this state. Note that the screw aligning plate 5 does not have to be made of metal as long as it is conductive, and a pickup signal can still be generated.

[0020] FIG. 4 shows another embodiment of the count display device 4, where (a) is a front view and (b) is an explanatory diagram of a unit corresponding to this count display device 4. As shown in FIG. 4(a), the count display device 4 has a setting section 42 that is composed of a first setting section 42a, a second setting section 42b, and a third setting section 42c, allowing three numbers to be set. As shown in FIG. 4(b), one unit 7 is capable of counting a configuration including three types of workpieces W (first workpiece W1 to third workpiece W3) each of which uses a different number of screws 6. Incidentally, if the count numbers in the second setting section 42b and the third setting section 42c are set to 0, the count display device 4 will have the same effect as the above embodiment.

[0021] 4, the shot count display section 41c indicates that two screws of the third workpiece W3 have been tightened, the unit count display section 41b indicates that 10 sets of the first workpiece W1 to the third workpiece W3 have been tightened, and the total count display section 41a indicates that a total of 97 screws have been tightened. In this way, by providing multiple setting sections 42 and using them according to the number of workpieces W of the unit 7 to be screwed, the number of screws fastened by the unit 7 equipped with multiple types of workpieces W can be counted effectively.

[0022] In the above embodiment, the count display device 4 is formed as a single box with the display unit 41, setting unit 42, operation unit 43, etc., provided on the front, but it may be formed as a personal computer. In this case, the display unit 41, setting unit 42, and operation unit 43 may be displayed on the display of the personal computer, and the signal input unit 44 may be prepared separately. Display on the display unit 41, etc. may be implemented by creating dedicated software. Also, the signal input unit 44 may be prepared by assembling the electric wire connection unit, the continuity determination circuit 44a, etc., in a dedicated housing, and the connection to the personal computer may be configured to output a signal corresponding to the keyboard, so that the keyboard connection unit of the personal computer can be used. Furthermore, if a personal computer is used, connection to a general-purpose network is easy, making it easy to manage a plurality of count display devices 4 and enabling centralized management of log data such as the number of screws fastened. [Explanation of symbols]

[0023] 1··Screw tightening count system, 2··Screw supplier (screw providing means), 2a··Guide member (accommodating section), 3··Electric screwdriver, 4··Count display device, 5··Screw alignment plate (screw providing means), 6··Screw, 7··Unit, 41··Display section, 41a··Total count display section, 41b··Unit count display section, 41c··Shot count display section, 42··Setting switch (setting section), 43··Operation section, 44··Signal input section, 44a··Continuity judgment circuit (pickup detection section), 44b··Torque-up signal input section, 45··Count display device CPU (screw tightening judgment section), W··Work.

Claims

1. A screw tightening counting system having a screw providing means, an electric screwdriver, and a count display device that displays the number of screws tightened, The screw providing means has a receiving portion for receiving the screw to be taken out, the receiving portion being formed of a conductive material, The count display device includes a pickup detection unit that generates a pickup signal when the storage unit and the bit of the electric screwdriver are electrically connected to each other; a torque-boost signal input unit for inputting a torque-boost signal output by the electric screwdriver; a screw tightening determination unit that determines whether or not the screw has been tightened; A display unit that displays the number of screws that have been determined to be completed, The screw tightening counting system is characterized in that the screw tightening determination unit determines that the screw tightening is completed when the torque-up signal is detected while the pickup detection unit is generating a pickup signal.

2. the screw supplying means is a screw supplying device having a mechanism for sequentially sending the screws to the storage part each time the screw is taken out by the electric screwdriver, 2. The screw tightening counting system according to claim 1, wherein the pickup detection unit generates a pickup signal when a guide member forming a part of the storage unit and a bit of the electric screwdriver are electrically connected to each other.

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