Electric heating – Heating devices – With power supply and voltage or current regulation or...
Reexamination Certificate
2000-02-09
2001-12-11
Hoang, Tu Ba (Department: 3742)
Electric heating
Heating devices
With power supply and voltage or current regulation or...
Reexamination Certificate
active
06329641
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device and a method for controlling a temperature of a soldering iron tip, and in particular, a device and a method for controlling a temperature, which achieve excellent temperature controlling characteristics with only simplified circuits.
2. Description of the Related Art
For example, a U.S. Pat. No. 5,043,560 has already been known as a method for controlling the temperature of a soldering iron tip, that is, a soldering tip. The invention varies a period of current flow of a soldering iron in a range from 0% to 100% in half the cycle of alternate current voltage, wherein a technology called a pulse width controlling system has been employed. As a rule, it is considered that the invention is excellent in its following ability since the temperature is controlled once every half cycle (H≈8.3 mS).
However, the present inventor examined and confirmed that even though the temperature is controlled once every several milliseconds, there is almost no difference in capacity between in the above case and in a case where the temperature is controlled once every tens of milliseconds, and control adaptive to a thermal response property of a soldering iron tip is sufficient.
Further, where a pulse control system is employed as in the above invention, since waves are generated in such a shape as shown in
FIG. 6
in response to the temperature of a soldering iron tip, voltage supplied to a heater is instantaneously switched from an OFF state to an ON state, and high frequency noise is generated. The nearer the current supply term (H−T) is to H/2, the more remarkably the high frequency noise becomes. Provisionally, even though a direct current voltage is supplied to the heater, the high frequency noise cannot be improved as far as a pulse width controlling system is employed.
Still further, the U.S. Pat. No. 5,043,560 has a complicated circuit configuration to achieve the invention, and, moreover, only simple performance can be displayed. Therefore, there remains an unsatisfactory point in the controlling capacity with respect to commencement and pause of operations.
The present invention was developed in view of the above shortcomings and problems, and it is therefore an object of the invention to provide a device and method for controlling a temperature of a soldering iron, which achieves excellent controlling capacity, with only simplified circuit configuration.
SUMMARY OF THE INVENTION
In order to solve the above object, a temperature controlling device according to the invention comprises a heating pulse generating portion which generates heating pulses having a zero voltage period exceeding an appointed width; a reference pulse generating portion for generating reference pulses on the basis of the heating pulses; a controlling portion for commencing a temperature controlling action in synchronization of the reference pulses; a heating portion for heating the soldering iron tip upon receiving the heating pulses and for outputting sensor signals corresponding to the temperature of the soldering iron tip; a switching portion, disposed between the heating pulse generating portion and the heating portion, which performs ON and OFF actions on the basis of control signals from the controlling portion; and an amplifying portion for transmitting the sensor signals to the controlling portion upon qualitatively receiving sensor signals from the heating portion; wherein the controlling portion makes “M” times the cycle of the reference pulses into a temperature controlling cycle T and controls the temperature of a soldering iron tip by providing heating pulses of a variable number N to the heating portion in the temperature controlling cycle T, and the controlling portion picks up sensor signals from the amplifying portion in the zero voltage period, determines a value of the variable number N on the basis of the sensor signals, and determines an ON-action time of the switching portion corresponding to the determined number N.
Since the heating pulse generating portion according to the invention generates heating pulses having a zero voltage period exceeding an appointed width, the controlling portion can pick up sensor signals from the amplifying portion by utilizing the zero bolt period. Therefore, as in prior art devices, it is not necessary to interrupt the heating pulses when picking up the sensor signals, and the amplifying portion can qualitatively receive sensor signals from the heating portion, whereby the circuit configuration and control can be simplified.
Also, since the controlling portion according to the invention makes “M” times the cycle of the reference pulses into a temperature controlling cycle T and controls the temperature of a soldering iron tip by providing heating pulses of a variable number N to the heating portion in the temperature controlling cycle T, it becomes possible to control the temperature in compliance with optimal frequencies responsive to the thermal response performance of a soldering iron tip. Further, since the controlling portion determines the value of the variable number N on the basis of sensor signals, and determines an ON operation time of the switching portion in response to the determined number N, there exists no heating voltage which is instantaneously raised from an OFF state to an ON state, whereby no high frequency pulse is generated.
In addition, the present invention is a temperature controlling device provided with a controlling portion which commences in a temperature controlling action in synchronization with reference pulses. The controlling portion makes a natural number M times the cycle of the reference pulses into a temperature controlling cycle T, the natural number M is selected corresponding to the different thermal properties for different soldering iron tips, and controls the temperature of a soldering iron tip by providing heating pulses of a variable number N corresponding to the temperature of the soldering iron tip in the temperature controlling cycle T. On the other hand, the controlling portion judges, in a case where said variable number N is continuously an appointed value or less, that the soldering iron is in a non-linear status, changes its operation mode from an action mode to a pause mode, and forcibly sets the value of the variable number N to zero.
With the invention, since a pause state of soldering work can be securely detected, and the temperature of the soldering iron is lowered in the pause state, useless power consumption can be decreased, causing the service life of soldering iron tips to be elongated. Further, in the invention, since the temperature of as soldering iron is lowered to around room temperature while in pause. Accordingly, should a user touch a part of the soldering iron tip, there is no fear that the user will receive a burn by mistake.
REFERENCES:
patent: 4243875 (1981-01-01), Chang
patent: 5043560 (1991-08-01), Masreliez
Miyazaki Mitsuhiko
Nagase Takashi
Abel David B.
Hakko Corporation
Hoang Tu Ba
Squire Sanders & Dempsey LLP
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