JP2012125872A - Control device of automatic hammer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device that solves a problem that an unnecessary strike after the striking of a work is finished causes noise regardless of a type of an automatic hammer and even if the automatic hammer is an existing one.SOLUTION: The control device 10 of the automatic hammer includes: a microphone 11 that converts a hit sound of the hammer into an electric signal to output it; a determiner 12 that determines a change of the hit sound on the basis of the electric signal output from the microphone 11; and a stop controller 13 that stops a striking operation of the hammer according to a result determined by the determiner 12.

Description

  The present invention relates to operation control of a fluid-driven or electric automatic tool.

  For example, regarding an air hammer that is a fluid-driven automatic hammer, as disclosed in Patent Document 1, there is a problem of noise due to wasted driving until the operator recognizes the completion of driving of the workpiece and returns the operation switch. In the case of Patent Document 1, this problem is dealt with by devising the internal structure of the air hammer, and a technique is disclosed in which a mechanism that automatically stops when the workpiece has been driven is built into the air hammer.

Japanese Patent Laid-Open No. 10-118959

  The above-mentioned problem concerning noise is a problem that applies not only to the fluid drive type but also to all automatic hammers including other models. However, it seems that it is not possible for those skilled in the art to apply the technique of Patent Document 1 to other than the air hammer, and it is also possible to modify the existing automatic hammer and apply the technique of Patent Document 1. difficult. The present invention focuses on this point, and a control device that can solve the problem of noise caused by wasted driving after the workpiece has been driven, regardless of the type of automatic hammer, even with an existing automatic hammer. suggest.

  In order to solve the above problems, an automatic hammer control device proposes a microphone for converting hammering sound into an electrical signal and outputting the electrical signal, and determining a change in the impacting sound based on the electrical signal output from the microphone. And a stop controller that stops the hammering operation according to a determination result by the determiner.

  The control device according to the above proposal is a device that detects a change in the hammering sound of the automatic hammer that changes before and after the workpiece has been driven and stops the operation of the hammer, and can be applied to the automatic hammer by external attachment or retrofit. Therefore, the present invention can be applied to any type of automatic hammer, and even an existing automatic hammer.

The figure which showed embodiment of the control apparatus of an automatic hammer.

The embodiment shown in FIG. 1 is an example applied to an air hammer which is a fluid-driven automatic hammer.
The air hammer 1 receives a supply of high-pressure air from a high-pressure air supply source 2 (for example, a compressor) as a power source, and the hammer 1a at the tip reciprocates. The work 3 in this example is a bush and is driven as a bearing into an aluminum transmission case 5 (for a vehicle) placed on a work table 4. A jig 6 is used for driving the work 3. The jig 6 is pressed against the head of the work 3 and the head of the jig 6 is hit with the air hammer 1. The air hammer 1 is controlled to start / stop the hitting operation by operating a trigger switch on the grip 1b.

The control device 10 for the air hammer 1 is interposed in the middle of a microphone 11 and a determination device 12 placed on the side of the work table 4 and a hose that sends air from the high-pressure air supply source 2 to the air hammer 1. A stop controller 13 is included.
The microphone 11 picks up the hammering sound of the hammer 1a, converts it into an electrical signal, and outputs it. A sound level meter may be used as the microphone 11. The determiner 12 is a data logger, for example, and monitors the amplitude of the electric signal output from the microphone 11 to determine a change in the hit sound. In the case of this embodiment, the stop controller 13 is an electromagnetic valve interposed in the middle of a hose that sends high-pressure air to the air hammer 1. The supply is shut off and the hammering operation of the hammer 1a is stopped.

  As an example, an application example to the air hammer 1 will be described. In the case of an electric automatic hammer, a high-pressure air supply source 2 as a power source is a power source, and a stop control is performed in the middle of an electric cord extending from the power source to the automatic hammer. A switch is interposed as the device 13.

  The determiner 12 determines the change in the hit sound by comparing the amplitude of the electrical signal output from the microphone 11 with a threshold value. For example, as shown in FIG. 1B, the determiner 12 is an operational amplifier that compares the voltage of the electrical signal converted from the impact sound with the threshold voltage Vref, and when the voltage of the electrical signal exceeds the threshold voltage Vref. The output of the operational amplifier activates the stop controller 13.

  The amplitude (voltage) of the electric signal output from the microphone 11 changes according to the magnitude of the hammering sound of the hammer 1a. According to the experiment, the hitting sound while driving the work 3 is 70 to 80 dB. When the driving of the work 3 is finished and the jig 6 hits the transmission case 5, the hitting sound increases. It changes to 110 dB. Therefore, in this case, if the threshold voltage Vref is set to a voltage of an electric signal corresponding to 100 to 105 dB of the striking sound, the control signal is sent from the determiner 12 when the striking sound becomes loud when the work 3 is driven. The stop controller 13 cuts off the power source and stops the hammering operation of the hammer 1a.

  If a data logger is used as the determiner 12, not only the amplitude determination of the electrical signal but also the frequency (wavelength) of the electrical signal is monitored, so that the change in the hitting sound can be captured. That is, not only the loudness but also the timbre, that is, the frequency of the sound, is not only the loudness but also the striking sound in the middle of driving the work 3 and the striking sound when the work 3 has been driven and the transmission case 5 is started. Since it changes, the frequency change of the electrical signal accompanying this change can be caught by a data logger and a control signal can be output to the stop controller 13.

  After the shut-off operation, the stop controller 13 can automatically return to a power source supply enabled state after a lapse of about 30 seconds, or can be manually returned to a power source supply enabled state by a switch operation or the like.

  As described above, according to the control device 10 of the present embodiment, the automatic hammer can be applied to either a fluid drive type or an electric type, and can be externally attached and retrofitted. It can be applied to all existing automatic hammers, and can solve the problem of noise caused by wasted driving after the workpiece has been driven.

DESCRIPTION OF SYMBOLS 1 Air hammer 2 High pressure air supply source 3 Workpiece | work 10 Control apparatus 11 Microphone 12 Judgment device 13 Stop controller

Claims (3)

A microphone that converts the hammering sound into an electrical signal and outputs it,
A determiner for determining a change in the hitting sound based on an electric signal output from the microphone;
A stop controller for stopping the hammering operation according to a determination result by the determination unit;
Composed of an automatic hammer control device.   The control device according to claim 1, wherein the determination unit determines a change in the hit sound by comparing an amplitude of the electric signal with a threshold value.   The control device according to claim 1, wherein the stop controller cuts off the supply of the power source of the hammer according to a determination result by the determiner.

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