JPH023667B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field> The present invention relates to an electric iron that can be used as a soldering iron, an electric iron, a branding iron, and the like.

<Prior Art> FIG. 9 shows an exploded perspective view of a conventional example. A soldering iron tip 34 having a hole 32 through which the heater penetrates and a vertical groove 33 is inserted into a rod-shaped heater 31, and the vertical groove 33 is tightened by sliding a spring 35 backward. There is. However, according to this conventional example, the area where the soldering iron tip comes into contact with the outside air is large, which results in a large amount of heat dissipation. In addition, the spring 35 loses its elasticity due to heating, making it impossible to obtain stable pressure, and there is a risk that the iron tip may fall off from the heater. Furthermore, poor heat conduction from the heater to the iron tip and large heat radiation from the iron tip to the outside air for the reasons described above require an increase in the temperature of the heater, which causes the handle 36
There are various drawbacks such as increased heat loss.

FIG. 10 shows an exploded perspective view of another conventional example. A plate-shaped heater 37 is sandwiched between a soldering iron tip 38 and a plate spring 39 from both sides, and inserted into a fixed pipe 41 provided on a handle 40, and a terminal 43 of the heater 37 is connected to a connector 42 provided on the front surface of the handle. A groove 44 is carved in the fixed pipe 41 in the axial direction, and the protrusion of the plate spring 39 fits into this groove 44. The plate spring 39 is configured to compress the heater 37 and the soldering iron tip 38 in a two-dimensional manner by screwing in the female thread of the root portion 47 of the shaped case 46.

However, according to this conventional example, the leaf spring 39 is in direct contact with the heater 37 over a wide area, and as a result, the spring 39 is naturally heated to a high temperature, resulting in a decrease in elasticity similar to the above-mentioned conventional example. It is difficult to maintain the strong pressing force between the heater and the tip of the iron. Furthermore, external forces such as twisting and bending that act on the tip of the soldering iron directly act on the heater and the connector of the heater, so there is a risk that these may be damaged. Furthermore, since the tip member 38 has a structure in which the tip end portion 48 protrudes through the hole 49 at the tip of the case 46, there are various drawbacks such as restrictions on the shape and dimensions of the tip tip portion 48.

<Purpose of the Invention> The present invention has been made in order to eliminate the above-mentioned drawbacks all at once, and has a structure in which the thermal resistance between the heater and the soldering iron tip is small, and the heat resistance between the heater or the soldering iron tip and the outside world is reduced. The purpose is to provide an electric iron with high resistance.

<Structure of the Invention> The electric iron of the present invention includes a rod-shaped electric heater, a hole through which the electric heater penetrates, a tapered insertion portion, and a tip having a cutting groove that vertically divides the insertion portion. an inner cylinder having an inner circumferential taper and an outer circumferential taper that is held concentrically with the electric heater and that fits around the outer periphery of the soldering iron tip insertion part, a male screw fixed to the handle, and a female screw that engages with the male screw. and an outer cylinder that is displaced in the axial direction and has a taper that suppresses the outer periphery of the inner cylinder.

<Description of Embodiment> FIG. 1 shows an exploded perspective view of an embodiment of the present invention, and FIG. 2 shows a longitudinal section in an assembled state.

A fixture 2 and an inner cylinder 3 are fixed to the front surface of the handle 1 with screws 4...4. The fixture 2 consists of a flange portion 21 and a cylindrical portion 22, and a male thread 23 is carved on the outer periphery of the cylindrical portion 22. The tip of the cylinder 3 widens into a cone shape, and has two axially symmetrical cut grooves 5, 5 formed therein, and a flange portion for being clamped by the fixture 2 at the base. A coiled spring 6 is fitted into the outer periphery of the central portion of the inner cylinder 3 to prevent the tip from expanding excessively.

The ceramic heater 7 has an elongated cylindrical shape, and is supported with some play against the inner cylinder 3 by a retaining ring 8 fitted near its rear end, and a lead wire 9 led out to the rear is provided in the handle 1. connected to a power supply control circuit (not shown). The retaining ring 8 has a generally circular flange shape and has a third
As shown in the figure, it has four claws 20, 20 on its outer periphery, and these claws 20 are fitted into holes bored in the inner cylinder 3.

The outer cylinder 10 is a member that covers the outside of the inner cylinder 3, and
The tip part expands into a cone shape with the same taper as the tip part of the inner cylinder, and a flange part 11 is formed at the base part. The fastening driver 12 has a cylindrical shape as a whole, and the flange portion 11 is attached to the inner periphery of the tip end thereof.
A circumferential groove is cut into which the groove is held, and a female thread 13 is cut on the inner surface extending from the groove to the rear end, and this female thread 13 fits into the male thread 23 of the fixture 2.

The soldering iron tip 14 has a hole 15 drilled in the center of the rear end through which the ceramic heater 7 penetrates, and an outer periphery 16 of the insertion portion.
is formed into a tapered shape with the same taper as the cylinder 3, cut grooves 17, 17 passing through the axis are carved, and a stepped portion 18 is formed at the end of the insertion portion. This soldering iron tip 14 is inserted between the ceramic heater 7 and the inner cylinder 3. FIG. 4 shows a cross-sectional view of this inserted portion. When inserting, there is no direction for the iron tip, but the fourth
As shown in the figure, the cut grooves 5, 5 of the inner cylinder 3
It is preferable that the grooves 17 and 17 of the soldering iron tip 14 are perpendicular to each other.

Next, a method for attaching the soldering iron tip 14 will be explained.

First, as shown in FIG. 5, the driver 12 with the outer cylinder 10 is screwed into the male screw 23 of the fixture 2 as far as it will go. In this state, the outer cylinder 10 is not pressing the inner cylinder 3, and the tip of the outer cylinder 10 is sufficiently expanded. Next, the soldering iron tip 14 is inserted. Next, rotate the driver 12 in the direction to return it to its original position, and
Displace it forward. When the driver 12 is tightened, the tapered part of the soldering iron tip 14, the tapered part of the inner cylinder 3, and the tapered part of the outer cylinder 10 are tightly and closely fitted together without any gaps.

The front half of the soldering iron tip used in the present invention may be formed into any shape depending on the purpose. An example is shown in FIG.

In addition, the shape of the insertion part of the soldering iron tip is chamfered orthogonally to the cut grooves 17, 17, as shown in the cross-sectional view in FIG. By doing so, when the inner cylinder 3 is tightened by the outer cylinder 10, the inner cylinder 3 escapes into the gap and is distorted from its perfect circular shape, thereby also serving as a spring action.

<Function> FIG. 8 shows a thermal equivalent circuit diagram representing the thermal phenomenon of the present invention as an electric circuit. Turn the heat source into a current source,
The heat transfer path is expressed as electrical resistance, and the heat capacity is expressed as capacitance. The meanings of the symbols attached to the figures are listed below.

T _H : Temperature of the heater Tt: Temperature of the iron tip Ta: Environmental temperature T _G : Temperature of the handle Ph: Power loss of the heater Ro: Thermal resistance between the heater and the iron tip Ra: Thermal resistance between the iron tip and the outside air R _L : Thermal resistance between the object to be heated and the outside air Rog: Thermal resistance between the heater and the handle Rag: Thermal resistance between the handle and the outside air Ca: Thermal capacity of the iron tip C _L : Thermal capacity of the object to be heated Sw: The iron Switch to indicate whether the tip is in contact with the heated object or not must be controlled as such.

Considering the path through which the heat generated by the heater is conducted to the iron tip using the circuit diagram above, in a thermal steady state, T _H = Ph・Ro+Ph・Ra+Ta…(1) However, since Rog》Ro, The heat escaping from the tip through the handle to the outside air is ignored.

Tt=Ph・Ra+Ta…(2) Therefore, from both equations (1) and (2) Tt−Ta/T _H −Ta=Ph・Ra/Ph・Ro+Ph・Ra =Ra/Ro+Ra…(3) From this equation As is clear, the iron tip temperature Tt is
Lower than heater temperature T _H. Furthermore, when the iron tip touches the object to be heated, the switch SW is turned on and heat is transferred to the heat capacity C _L transiently, but after that, when the steady state is reached, the circuit with the thermal resistance Ra is replaced by the circuit with the thermal resistance R _L. Since they are in parallel contact, heat radiation to the outside air increases and the soldering iron tip temperature Tt further decreases.

Regardless of whether the switch SW is on or off,
Thermal resistance is
It is important to keep Ro small. Looking at this from another perspective, if the thermal resistance Ro is small,
It is possible to bring the heater temperature T _H closer to the iron tip temperature Tt, and lowering the heater temperature T _H
Less heat is radiated to the outside air through the thermal resistances Rog and Rag, which also lowers the handle temperature _T.

In order to reduce the thermal resistance Ro, it is necessary to bring the iron tip and the heater into contact with as wide a contact area as possible, and to press them together strongly so that there are no gaps or other poor thermal conductors between them. is necessary.

According to the present invention, since the cutting grooves 17, 17 are provided in the soldering iron tip 14 inserted into the ceramic heater 7, even if there is an error in the outer diameter dimension of the ceramic heater 7 and the inner diameter dimension of the hole 15, both Since they are in direct contact with each other, the thermal resistance Ro becomes extremely small. Further, the outer diameter of the driver 12 can be increased, and since the driver 12 is displaced in the axial direction by the screw, the axial force becomes very large.
Since the inner circumferential surface of the outer tube 10, the inner and outer circumferential surfaces of the inner tube 3, and the outer circumferential surface of the insertion portion of the soldering iron tip 14 are tapered at the same rate, the force magnified by the wedge principle is applied to the insertion portion of the soldering iron tip. As a result, the ceramic heater 7 and the soldering iron tip 14 are strongly tightened. Therefore, the thermal resistance Ro becomes a very small value.

Further, according to the present invention, since the heat generating part and the root part of the ceramic heater 7 are spatially partitioned by the retaining ring 8, the heated high temperature air does not convect toward the handle, thereby increasing the thermal resistance Ro. moreover,
Since the retaining ring 8 is supported by the inner cylinder 3 with some play, the distortion that occurs in the ceramic heater when an external force such as twisting or bending is applied to the soldering iron tip 14 is reduced.

In general, the elasticity of spring materials deteriorates at high temperatures, but in the present invention, the inner cylinder and the soldering iron tip are sandwiched by the cone portion of the outer cylinder, which is insulated from the iron tip by the inner cylinder 3, so that the elasticity of the spring material deteriorates. Sexual deterioration is not a problem.

<Effects of the Invention> As described above, according to the present invention, the contact area between the heater and the soldering iron tip is wide, the two are strongly pressed and held, and the outer periphery of the contact portion between the two is formed by the inner cylinder, Since it is isolated from the outside world by the outer cylinder, retaining ring, etc., the temperature difference between the heater temperature and the iron tip temperature is small. It is possible to maintain the temperature close to the target value, and furthermore, it is possible to suppress the heat transmitted to the handle.

Further, the soldering iron tip can be easily removed by simply retracting the outer cylinder by rotating the driver, and various shapes of soldering iron tips can be used interchangeably.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing an embodiment of the present invention;
The figure is a longitudinal sectional view, FIG. 3 is a sectional view taken along line A-A in FIG. 2, FIG. 4 is a sectional view taken along line B-B in FIG. 2, and FIG. . FIG. 6 is an external perspective view showing another embodiment of the present invention, and FIG. 7 is a B-B showing a modified embodiment of the soldering iron tip insertion portion 16 of the present invention.
B sectional view and FIG. 8 are thermal equivalent circuit diagrams for explaining the action of the present invention. FIG. 9 and FIG. 10 are exploded perspective views showing separate conventional examples. 1...Handle, 2...Fixing tool, 3...Inner cylinder,
5... Cut groove of inner cylinder, 7... Ceramic heater,
8...Retaining ring, 9...Heater lead wire, 1
0... Outer tube, 12... Driver, 13... Female thread, 14... Solder tip, 15... Solder tip hole, 16
...Taper of the insertion part of the soldering iron tip, 17... Cutting groove of the soldering iron tip, 23... Male thread of the fixing tool.

Claims (1)

[Claims] 1. A rod-shaped electric heater, a soldering iron tip having a hole through which the electric heater penetrates, a tapered insertion portion, and a cutting groove that vertically divides the insertion portion; An inner cylinder with an inner circumferential taper and an outer circumferential taper that is held concentrically and fits on the outer periphery of the soldering tip insertion part, a male screw fixed to the handle, and a female screw that fits into the male screw and is displaced in the axial direction. and an outer cylinder having a taper that suppresses the outer periphery of the inner cylinder. 2. The electric iron according to claim 1, wherein the inner cylinder is formed of a plate material and has a longitudinal cut groove cut therein. 3. The electric heater is made of a ceramic heater, and a retaining ring is fixed to the base of the ceramic heater to close the gap between it and the inner cylinder, and a claw formed on the outer circumference of the retaining ring is attached to the inner cylinder. Claim 1, which fits into the drilled hole.
Electric iron as described in section.