JP3125335B2 - Cumulative time measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cumulative time measuring device used for measuring a loss time in a factory manufacturing process.

[0002]

2. Description of the Related Art A conventional cumulative time measuring apparatus will be described below. FIG. 5 is a perspective view of a conventional cumulative time measuring device used in a manufacturing process of a factory.

[0005] In FIG. 5, reference numeral 1 denotes a conveyor belt on a production line, on which a pallet 3 on which an assembly 2 is mounted is placed at an appropriate interval. The assembly 3 undergoes various assemblings and inspections in each process, and flows in the R direction each time the assembling and inspections are completed.

Here, a predetermined unit time required for assembly and inspection in each process is called a tact time.
For efficient production, the tact time is set substantially equal in each step. If a trouble occurs in any of the processes and a long tact time is required, the transport belt 1 stops during that time, causing a loss in the entire production.

[0005] Reference numeral 4 denotes a cumulative time measuring device for measuring the cumulative loss time. Reference numeral 5 denotes a detection unit which, when detecting the assembly 2 on the pallet 3, transmits a detection signal to the cumulative time measuring device 4. In the cumulative time measuring device 4, the signal is analyzed by an arithmetic unit constituted by a microcomputer or the like, and the result is displayed on the digital display unit 6. About the display contents,
For example, target, schedule, actual, difference, achievement rate, total, remaining number,
There are operating rates and the like, and what is displayed on the display section is switched by the changeover switch 7 and displayed.

As described above, in the actual production process, the loss time is calculated from the difference between the tact time and the operation time, and analysis is performed to find out where the cause of the loss is, and to find a clue for solving the problem.

[0007]

However, in such a conventional configuration, the type of information to be known is first selected and set by the changeover switch 7, and then the digital display must be carefully read. was there.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a cumulative time measuring device which allows the total loss time of a manufacturing process to be known at a glance.

[0009]

In order to achieve the above object, an accumulative time measuring apparatus according to the present invention comprises a detecting section for detecting passage of an object, and a time measuring section for starting a measurement every time an output from the detecting section is performed. And a drive signal output to the analog time display section when the value of the time measurement section exceeds a predetermined time.

[0010]

According to this structure, when the time required for the assembly to accumulate in front of the detection section exceeds a predetermined time, a drive signal is output to the analog time display section and displayed only for the time exceeding the predetermined time. The total loss time of the process can be known at a glance.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view of the cumulative time measuring device of the present invention used in the manufacturing process of a factory.

In FIG. 4, reference numeral 1 denotes a conveyor belt on a production line, on which a pallet 3 on which an assembly 2 is mounted is placed at an appropriate interval. The assembly 3 undergoes various assemblings and inspections in each process, and flows in the R direction each time the assembling and inspections are completed.

Reference numeral 11 denotes a detection unit attached to the side of the process, and detects the presence or absence of the assembly 2. Then, the signal is connected to the time measuring unit 12 to measure the loss time, and the loss time is displayed on the analog time display unit 13.

FIG. 1 is a block diagram of a cumulative time measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a timing chart thereof. In FIG. 1, reference numeral 11 denotes a detection unit for detecting an assembly 2, and an output A of the detection unit 11 is a delay circuit 1
4 and is delayed for a fixed time. The output B of the delay circuit 14 is a monostable multivibrator circuit 1.
5 and to one input of an AND circuit 16. The output A of the detection unit 11 is connected to the reset terminal R of the monostable multivibrator circuit 15. The negative output Q2 of the monostable multivibrator circuit 15 is output to the other input of the AND circuit 16. The output of the AND circuit 16 is supplied as drive power to the analog clock display unit 13 via the drive circuit 17.

The operation of the thus-configured cumulative time measuring device will be described below with reference to FIGS. 1 and 2.

FIG. 2A shows an output waveform of the detection unit 11.
A high level indicates that the assembly 2 is in front of the detection unit 11. When the output signal A of the detection unit 11 passes through the delay circuit 14, the output waveform B is delayed by a minute time TD as compared with the waveform A. This surely resets the monostable multivibrator circuit 15 with the signal A (Q1 in FIG. 2).
A) This is for setting later with the B signal (Q1B in FIG. 2). Q1 is a positive output of the monostable multivibrator circuit 15. Here, the monostable multivibrator circuit 15
Is set slightly longer than the tact time. Therefore, normally, when the assembly 2 is flowing normally, the reset is performed before the monostable pulse width TW of the monostable multivibrator circuit 15 is turned off. However, if some abnormality occurs and the assembly 2 stays for TW + A1 time before the detection unit 11, the monostable multivibrator circuit 15 is not reset by the falling edge of the A signal, so that a preset monostable multivibrator circuit 15 is set. It becomes low level (Q1C) after the pulse width TW time.

The Q2 signal waveform is a negative output of the Q1 signal waveform. Therefore, the output of the AND circuit 16 of the Q2 waveform signal and the B signal waveform (after that, the output passed through the drive circuit 17) is as shown in the waveform D. That is, the driving circuit 1
7 outputs an AND signal waveform D of the Q2 signal waveform and the B signal waveform. As a result, the A1 time, which is the AND output, is supplied to the analog clock display unit 13 and accumulated as a loss time.

That is, the analog clock display unit 13 is a normal analog battery clock, and supplies a D signal as a drive signal instead of the battery of the battery clock. Therefore, this battery timepiece functions as a kind of nonvolatile memory when the D signal is turned off, and the time is accumulated every time the D signal is turned on.

Next, a specific circuit of this embodiment will be described with reference to FIG. In FIG. 3, 21 is a switch,
Reed switches, micro switches, etc. can be used. The switch 21 detects the presence or absence of the assembly 2 in the manufacturing process, and is provided near the conveyor belt 1. This switch 21 is connected to the resistor 22 and the LE of the photocoupler 23.
It is connected between the power supply and the ground in series with D24. LE
The optical signal of D24 is transmitted to the phototransistor 26 connected in series with the resistor 25. Then, this signal becomes the output signal A of the detection unit 11 through the NAND gate 27.

Here, since the signal of the switch 21 is once converted into an optical signal by the photocoupler 23, it is resistant to external noise. In addition, it has a feature that the insulation of both circuits is high.

A low-pass filter is formed by the resistor 28 and the capacitor 29 to delay the signal for a very short time, and then the NAND gates 30 and 31 are connected in series to form a delay circuit 14.
Is obtained. This delay time is about 100 microseconds.

Reference numeral 32 denotes a monostable multivibrator IC. An external capacitor 40, a fixed resistor 33 connected in series with the capacitor 40, and a variable resistor 34 generate a monostable pulse width TW corresponding to a tact time. You have set. The pulse width TW is set to be continuously variable by the variable resistor 34 for 3 to 30 seconds. Therefore, the tact time can be easily set by the variable resistor 34, and even if the process is changed, it can be easily handled.

Next, reference numeral 35 denotes a NAND gate whose output C
Is supplied to the base of the transistor 36 constituting the drive circuit 17. The emitter of the transistor 36 is connected to the power supply, and the collector is divided by the resistors 37 and 38 and supplied from the division point D to the power supply of the analog clock display unit 13. The analog clock display unit 13 uses a generally available battery clock.

Reference numeral 39 denotes a capacitor inserted between the D signal and the ground, which stabilizes the power supplied to the analog timepiece display unit 13 and ANDs the output B of the delay circuit and the negative output Q2 of the monostable multivibrator. Is used to eliminate spike noise DN due to the delay time.

As described above, according to this embodiment, since the analog clock is used for the display unit, the accumulated loss time can be known at a glance.

Further, since the analog timepiece is directly driven by the output from the drive circuit 17, it is sufficient to supply power only when necessary, which contributes to power saving.

Further, the time measuring unit 12 is formed by a simple logic circuit.
Therefore, the number of parts is small and the number of failures is small.
In addition, it can be realized at low cost and can be downsized.

[0029]

As described above, according to the present invention, a detecting section for detecting the passage of an object, a time measuring section for starting measurement each time an output from the detecting section is performed, and the value of the time measuring section is Since it is configured to output a drive signal to the analog time display section when it exceeds a predetermined time,
If the time during which the assembly accumulates in front of the detection unit exceeds a predetermined time, a drive signal is output to the analog time display unit and displayed only for the time exceeding the predetermined time, so that the accumulated loss time of the manufacturing process is calculated. You can know at a glance.

Therefore, there is an effect that the operation management can be easily performed without wasting time in the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a block diagram of a cumulative time measuring device according to an embodiment of the present invention.

FIG. 2 is a time chart of a cumulative time measuring device according to an embodiment of the present invention.

FIG. 3 is a circuit diagram of a cumulative time measuring device according to an embodiment of the present invention;

FIG. 4 is a perspective view showing a use state in a manufacturing process of the cumulative time measuring device according to one embodiment of the present invention.

FIG. 5 is a perspective view showing a state of use of a conventional accumulated time measuring device in a manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Detecting part 12 Time measuring part 13 Analog time display part 14 Delay circuit 15 Monostable multivibrator circuit 16 AND circuit 17 Drive circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G04F 10/00

Claims (5)

(57) [Claims] 1. A detecting section for detecting passage of an object, a time measuring section for starting measurement each time an output from the detecting section is provided, and an analog time when a value of the time measuring section exceeds a predetermined time. A cumulative time measuring device that outputs a drive signal toward a display unit. 2. The cumulative time measuring device according to claim 1, wherein the analog time display section is directly driven by an output signal from the time measuring section. 3. The time measuring section resets with an output signal from the detecting section, and delays the output signal of the detecting section (B).
A monostable multivibrator circuit, a negative output of the monostable multivibrator circuit, an AND circuit for inputting the delayed signal (B), and a drive circuit for driving an analog clock display unit with the output of the AND circuit 3. The cumulative time measuring device according to claim 2, comprising: 4. The cumulative time measuring device according to claim 3, wherein the set time of the monostable multivibrator circuit can be changed. 5. The cumulative time measuring device according to claim 1, wherein the detecting section comprises a contact and a photocoupler mounted at a position distant from the contact and driven by a contact on / off signal of the contact.