JPH0639331U - Control circuit of automatic screw tightener - Google Patents

Abstract

(57) [Summary] [Purpose] To make sure that the automatic screw tightener will tighten the screws. [Structure] An external controller for driving and controlling the automatic screw tightener is provided with functions of a start signal, a reset signal, and a signal for setting the number of times screw tightening is repeated, and the cylinder is controlled by a command signal (start, reset) from this external controller. An OR circuit 12 and a flip-flop 13, an OR circuit 14 and 15 for controlling the driver, a flip-flop 16 and a timer 17, an AND circuit 11 for inputting a torque-up signal and a screw floating sensor signal and outputting a screw tightening completion signal, Further, it is composed of a timer 1, a counter 2, a comparator 3 and a data set 4 for controlling the repeated driving of the driver.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control circuit for controlling the drive of an automatic screw tightener that is widely used as a part of FA for industrial machinery.

[0002]

[Prior art]

 A conventional automatic screw tightener is driven and controlled by a command signal from an external controller, but a series of sequence operations are performed by a program provided in its control circuit. Due to, the work to tighten the screw was only once.

FIG. 3 is a block diagram showing a configuration of a control circuit of a conventional automatic screw tightening machine, and FIG. 4 is a flowchart of a screw tightening process. The Q output of the flip-flop 13 becomes "H" by a command signal (start) from an external controller (not shown) attached to the automatic screw tightener, and the cylinder starts driving. Further, since the Q output of the flip-flop 16 also becomes "H", the driver starts rotating and the timer 17 also starts operating. Next, when stopping the automatic screw tightener, the Q output of the flip-flop 13 becomes "L" through the OR circuit 12 by the command signal (reset) of the external controller, so that the cylinder stops, Since the Q output of the flip-flop 16 also becomes "L", the rotation of the driver also stops, and the timer 17 also stops measuring. When the screw tightening torque reaches the specified value and the screw floating sensor is inoperative, the output of the AND circuit 11 becomes "H" and the screw tightening completion signal is output. When the driver continues to drive beyond the time set in the timer 17, a screwing error signal is output, and the driver and the cylinder are connected via the OR circuit 12, the flip-flop 16 and the flip-flop 13. Stop.

FIG. 4 is a flow chart showing a screw tightening process of the above-described automatic screw tightener, in which screw tightening (timer start) (S21) is performed by a command signal from an external controller, and time up (S22) is NO. If the torque up (S23) is YES and the screw float (S25) is NO, the screw tightening is completed (S27) and the screw tightening operation is completed. When the torque up (S23) is NO and the screw float (S25) is YES, the process returns to the step of time up (S22) and the above steps are repeated until the time up (S22) If YES, then stop via a tightening error (S26).

[0005]

[Problems to be solved by the device]

 If the member to be screwed has good machinability like steel, there weren't many problems, but if it is made of plastic or casting, the machinability is not so good that there is variation in the prepared hole. As a result, tightening the screw with the specified torque once may not be sufficient, which may cause the screw float sensor to operate, resulting in frequent screw tightening errors. The present invention has been made to eliminate the above-mentioned defects of the conventional automatic screw tightening machine, and provides a control circuit of the automatic screw tightening machine having a highly reliable external controller capable of performing proper screw tightening. The purpose is to do.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the control circuit of the automatic screw tightener according to the present invention sends a command signal (the number of repetitions of start, reset and screw tightening operation) from an external controller attached to the automatic screw tightener. The automatic screw tightener is driven and controlled via the control circuit provided in the automatic screw tightener, the screw tightening operation is repeated until the screw tightening is completed, and when the screw tightening is completed, the screw tightening completion signal is output. It is displayed on the external controller.

[0007]

[Action]

 The number of repetitions that is suitable for the material of the screw tightening member is set in the control circuit of the automatic screw tightening machine by the switch that sets the number of repetitions of the screw tightening operation provided in the external controller. The automatic screw tightener starts the screw tightening operation according to the command signal (start) from the external controller, and repeats the screw tightening operation within the preset number of repetitions until the screw tightening is completed.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a control circuit of an automatic screw tightener according to the present invention, and FIG. 2 is a flowchart of a screw tightening process according to the present invention.

In FIG. 1, the data set 4 has a repeat count B set by a switch provided in an external controller (not shown) for setting the repeat count of the screw tightening operation. When driving the automatic screw tightener, the Q output of the flip-flop 13 becomes "H" in response to a command signal (start) from the external controller, a cylinder drive signal is output, and the OR circuit 14 is used. The CLK terminal input of the flip-flop 16 is set to "H". On the other hand, the output signal of the data set 4 is input to the comparator 3, but since A = 0 in the initial setting, A <B, and the D terminal input of the flip-flop 16 is also "H". Therefore, the Q signal of the flip-flop 16 becomes "H" by the command signal (start), the driver drive signal is output, and the timer 17 also starts operating.

When the automatic screw tightener is stopped, the Q output of the flip-flop 13 becomes “L” via the OR circuit 12 by the command signal (reset) of the external controller, and the cylinder is stopped. Further, the Q output of the flip-flop 16 becomes "L" via the OR circuit 15, and the driver and the timer 17 are stopped.

When the screw tightening torque reaches the specified value and the screw floating sensor does not detect the screw floating, the output of the AND circuit 11 becomes “H” and the screw tightening completion signal is output to the external controller. At the same time, the cylinder is stopped via the OR circuit 12 and the flip flop 13, and the driver is stopped via the OR circuit 12, the OR circuit 15 and the flip flop 16. Also, the timer 17, the counter 2, and the timer 1 are reset.

When the automatic screw tightener completes the screw tightening operation, the torque up signal causes the F / F 16 to be reset once via the OR circuit 15. At the same time, the timer 17 is also reset, and the timer 1 outputs a one-shot pulse by the same signal, increments the count number A of the counter 2 by one, and inputs the CLK terminal of the flip-flop 16 via the OR circuit 14. Is "H". At this time, if B> A, the D terminal input of the flip-flop 16 also becomes “H” and the Q output also becomes “H” via the comparator 3, so that the driver drive signal is transmitted and the timer 17 starts measuring. Let Thereafter, the automatic screw tightener is driven within the range of the repeatedly set number of times B until the screw is not lifted by the same repeated operation.

The flowchart of the screw tightening process of FIG. 2 is a detailed description of the above-described screw tightening operation for each step. If the selection of A ≧ B (S2) is NO, the screw tightening (S3) is performed. When the start is started, the selection of time-up (S5) is NO, the selection of torque-up (S6) is YES, and the selection of screw floating (S7) is NO, the screw tightening is completed (S10). If the selection of the screw float (S7) is YES, the number of counts is set to A = A + 1 (S11) and the process returns to the step (S2) to repeat the screw tightening operation. When the screw tightening frequency A becomes A ≧ B, a screw float error signal is output from the comparator 3, and when the timer 17 operates for more than the specified time, a screw idle error signal is output and the above-mentioned 2 Two error signals are displayed on the external controller.

[0014]

[Effect of device]

 As described above, in the control circuit of the automatic screw tightener according to the present invention, the number of times of screw tightening is set in advance by the external controller, and the screw tightening operation is repeated until the screw reaches the proper tightening torque. The screw tightening process is displayed by displaying a screw floating error signal and a screw idling error signal together with the screw tightening completion signal on the external controller. Therefore, even if there is a problem with the material of the member to be screwed, the screw can be tightened properly, and the reliability of screw tightening can be secured.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit of an automatic screw tightener according to the present invention.

FIG. 2 is a flowchart of a screw tightening process of the present invention.

FIG. 3 is a block diagram showing a configuration of a control circuit of a conventional automatic screw tightening machine.

FIG. 4 is a flowchart of a conventional screw tightening process.

[Explanation of symbols]

 1, 17 timer 2 counter 3 comparator 4 data set 11 AND circuit 12, 14, 15 OR circuit 16, 17 flip-flop

Claims (1)

[Scope of utility model registration request] 1. A control circuit for an automatic screw tightener that drives and controls an automatic screw tightener according to a command signal from an external controller, wherein the number of repetitions of screw tightening operation is set via the external controller to ensure that the screw is appropriate. The screw tightening operation is repeated within the preset number of repetitions until the tightening torque is reached, and when the screw tightening is completed, the screw tightening completion signal is displayed on the external controller and the screw tightening error signal is also displayed. A control circuit for an automatic screw tightener.