JPH02268967A - Electric soldering iron - Google Patents

Abstract

PURPOSE:To reduce the thermal resistance between a heater and a soldering iron tip and to control a temperature of the iron tip near a desired value by inserting and holding a rod-like electric heater strongly in the axial direction by both ends of the root part and the tip, and allowing the electric heater and an iron tip member to abut strongly on each other. CONSTITUTION:An iron tip member 10 has a cylindrical part for fitting a rod- like electric heater 1 to a heater built-in part. A hole 11 having the bottom for pressing the tip face of the electric heater in the axial direction is pieced, and a iron tip 12 is provide on its tip, and also, a taper 14 is formed on the outside periphery of the cylindrical part. A fixed pipe 15 having a holding part 16 for abutting on the taper of this iron tip member, and a flange-like detaining part 17 extended to the root side from said cylindrical part is provided. This electric soldering iron is provided with a first flange 5 provided integrally with the root part of said electric heater and handle 7 for supporting it, and a joining means for drawing a part between the flange 5 and the flange- like detaining part 17. In such a way, only compressive force works on the rod-like electric heater and torsion and bending do not work thereon, and it does not occur that the electric heater is damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electric iron that can be applied to a soldering iron, a hair iron, and the like.

<Prior art> The present inventor has disclosed the patent application No. 163294/1986 (Japanese Patent Application No.
-42481 Publication), the temperature difference between the heater temperature and the iron tip temperature is reduced by reducing the thermal resistance between the heater and the iron tip and increasing the thermal resistance between the heater or the iron tip and the outside world. Therefore, we are proposing an electric iron that can control the tip temperature close to the target value, and that also suppresses the heat transmitted to the handle to improve efficiency.

Furthermore, recently, ceramic heaters in which the heater is embedded within ceramic have become popular in order to prevent oxidation of the heater and extend its life. However, the dimensions of this ceramic heater shrink due to the firing process, and since it is ultra-hard, it cannot be cut or cut.
It is not easy to polish and therefore has extremely poor dimensional accuracy. Currently, there are many soldering irons that use ceramic heaters on the market, but in all of them, the adhesion between the iron tip member and the ceramic heater is poor. However, there was a drawback that the iron tip temperature decreased. On the other hand, if the heat capacity of the iron tip member is increased by increasing the size of the iron tip member, the above disadvantages can be alleviated to some extent, but the heater temperature must be set higher than the iron tip temperature, and the ceramic The temperature of the handle rose due to insufficient insulation between the heater and the handle, making it too hot for the operator to hold the handle with bare hands.

<Problem to be solved by the invention> The above-mentioned prior invention has the advantage that the temperature difference between the heater temperature and the iron tip temperature is small, and the heat transmitted to the handle is small. Since the electric heater is held only by the frictional force generated by the electric heater, there is a problem that the fastening force changes depending on the temperature change.Also, since the electric heater is held by its lead wire, the holding force is insufficient, and the fastening driver There is a problem in that the electric heater tends to be twisted when tightened.

The object of the present invention is to realize an improved electric iron that solves these problems and also solves the above-mentioned drawbacks of products currently on the market.

<Means for Solving the Problems> The electric iron of the present invention includes a rod-shaped electric heater, a cylindrical portion that fits into at least a built-in portion of the electric heater, and a bottom that presses the tip end surface of the electric heater in the axial direction. An iron tip member having a hole bored therein, a tip provided at the tip thereof, and a taper formed on the outer periphery of the cylindrical portion, and a suppressor that comes into contact with the taper of the iron tip member. a fixed pipe having a flange-like locking portion extending toward the base side of the cylindrical portion; and an axial groove provided in a portion of the iron tip member that corresponds to the suppressing portion and further toward the base side; A first flange provided integrally with the base of the electric heater, a handle for supporting the first flange, and a fastening means for pulling between the first flange and the flange-like locking part. Characterized by. Further, the fastening means of the present invention includes a flange member having a second flange that jointly holds the first flange with the handle, and a fastening member that tightens the tip of the flange member and the flange-like locking part. It can be configured as follows.

<Operation> FIG. 3 shows a thermal equivalent circuit diagram representing the thermal phenomenon of the present invention as an electric circuit. The heat source is expressed as a current source, the heat transfer path as electrical resistance, and the heat capacity as capacitance. The meanings of the symbols attached to the figures are listed below.

TH: Temperature of the heater T5: Temperature of the tip T,: Environmental temperature TG: Temperature of the handle Ph: Power loss of the heater Ro: Thermal resistance between the heater and the tip R1: Heat between the tip and the outside air Resistance RL: Thermal resistance between the object to be heated and the outside air R09: Thermal resistance between the heater and the handle Ra1l: Thermal resistance between the handle and the outside air C,: Heat capacity of the tip CL: Heat capacity of the object to be heated So: A switch that indicates contact or non-contact between the tip and the object to be heated.Generally, in a heater that heats the tip using an electric heater, when controlling the energization of the heater, the tip temperature Tt
must be controlled so that the deviation between the value and the target value is as small as possible.

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, TH=Ph-RO+Ph-Rm+T,...
(1) However, since Ro e > Ro, the heat escaping from the iron tip to the outside air through the handle is ignored.

T t −P h・R, +T, ・・・
・Since (2) is (11 (21 2 and 2, 'r, -'r, Ph-R.

Tll TM PH・Ro+ Ph・Ra
R1 (3) Ro + Rs As is clear from this equation, the iron light temperature T is lower than the heater temperature TH. Furthermore, when the tip touches the object to be heated, the switch SW is turned on and heat is transferred to the heat capacity CL transiently, but after that, in a steady state, the thermal resistance R8
Since the circuit of thermal resistance RL is connected in parallel to the circuit of , heat radiation to the outside air increases and the iron light temperature T further decreases.

Regardless of whether the switch SW is on or off, it is important to keep the thermal resistance Ro small in order to keep the variation in Tt low. If you look at this differently,
When the thermal resistance R0 is small, it is possible to bring the heater temperature TH close to the iron light temperature T, which lowers the heater temperature T□ (which means that less heat is radiated to the outside air through the thermal resistance R691R119, and the handle temperature decreases. This also results in a decrease in TG.In order to reduce the thermal resistance RO, it is necessary to strongly press the tip and heater together.

Now, in the configuration of the present invention, by tightening the fastening means, the first
The flange of the flange and the flange-shaped locking part of the fixed pipe are pulled strongly, and as a result, the holding part of the fixed pipe presses the taper of the tip member in a diagonal direction with respect to the axial direction, and a component of force directed toward the axial center is generated. The root portion of the tip member is tightened to reduce the groove width of the split groove, and the axial component force strongly presses the electric heater and the tip member. In addition, most of the heat transmitted from the electric heater to the handle side is released to the outside air through the first flange, and the thermal resistance between the first flange and the handle is extremely large. Since the passage is blocked by the first flange, the temperature rise in the handle is kept very low.

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

A temperature sensor 2 is buried in the tip of the round bar-shaped ceramic heater 1, followed by a heating element 3, and each lead wire is led out from the rear end and connected to a terminal plate 4. A first flange 5 is integrally joined to the base of this ceramic heater by brazing. The flange 5 is made of a material with good thermal conductivity and relatively low bending stress, such as nickel or an alloy thereof. For example, three through holes ε...6 are bored on the outer periphery of the flange 5.

The handle 7 is made of a thermally poor conductor such as plastic or wood, and has a flange portion 8 formed at its tip, and three seat portions 9 on the end surface of the flange portion 8 that correspond to the through holes described above.
9 is integrally formed, and a female thread is carved into the seat. The center of the handle 7 is hollow and accommodates the terminal plate 4 and the like.

The iron tip member 10 is provided with a hole 11 having a cylindrical portion that fits into at least the built-in portion of the electric heater 3 of the ceramic heater 1 and a bottom that abuts the tip surface 1a of the ceramic heater 1.
A soldering tip 12 is provided at the tip, an axial groove 13 is carved in the portion where the hole 11 is formed, and a taper 14 with a tapered tip is formed on the outer periphery of the cylindrical portion.

The fixed pipe 15 fits onto the outer periphery of the cylindrical portion of the soldering tip member 10 and wraps it, and
and the rear end 10a of the tip member 10.
A flange-like locking portion 17 is formed that extends further toward the root side.

The flange member 18 has a second flange 19 for clamping the first flange 5 together with the seats 9...9 of the handle 7, and a male thread 20 integral therewith, and A through hole 21 is bored with a sufficient gap therebetween. The thread diameter of this male thread 20 is approximately equal to the outer diameter of the flange-like locking portion 17 described above. The fastening member 22 is a member for connecting the flange-like locking portion 17 and the male thread 20 and pulling them together.

When assembling this, after connecting the terminal plate 4 etc. of the ceramic heater 1, the first flange part 5 is brought into contact with the seat part 9...9 of the handle 7, and the flange member 18 is placed on top of it. Then, fix it to the handle with screws 23...23. Next, the iron tip member 10 is inserted into the tip of the ceramic heater 1, and then the fixing pipe 15 is inserted onto the iron tip member 10, and the fastening member 22 is tightened to complete the assembly work.

In this state, the taper 14 of the tip member 10 is strongly pressed by the holding part 16 of the fixed pipe 15, and the axial component of the force acting on the pressing surface causes the tip member 10 and the ceramic heater 1 to axially move. The soldering iron tip member 10 tightens the outer periphery of the ceramic heater 1 and brings it into strong contact with the outer periphery of the ceramic heater 1 by pressing strongly in the direction, and the radial component force acts on the axis. In addition, the roundness or axial straightness of the ceramic heater 1, or the first
Even if the fixing angle of the flange 5 is deviated from the ideal value, since the first flange 5 has deformability, these manufacturing errors can be absorbed and the ceramic heater 1 and tip member 10 can be fixed. Since the first flange 5 is deformed so that the contact between the ceramic heater 1 and the ceramic heater 1 is the closest, the bending stress and torsional stress applied to the ceramic heater 1 are alleviated. Furthermore, seats 9...9 are provided on the tip end surface of the handle 7, and as a result, a poor thermal conductor is formed by outside air between the first flange 5 fixed to the ceramic heater 1 and the handle 7.

The electric heater of the present invention is not limited to the ceramic heater described above. For example, an electric resistor and a temperature sensor are housed in a stainless steel pipe, and the space is filled with, for example, magnesia (MgO) or alumina powder dissolved with water glass. It can also be implemented by filling it with a heat-resistant insulating material.

<Effects of the Invention> According to the present invention, the electric heater and the iron tip member are brought into strong contact with each other by strongly clamping the rod-shaped electric heater in the axial direction at both ends of the base and tip. The thermal resistance R6 during this period becomes extremely small, and the iron light temperature is always controlled close to the target value.

In addition, only compressive force acts on a rod-shaped electric heater,
Since there is no tearing or bending during attachment/detachment or use, the electric heater will not be damaged even when using a highly brittle material such as ceramic. Further, since the structure is simple and the number of parts is small, assembly work is easy and it can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention, FIG. 2 is a vertical sectional view of the assembled state, and FIG. 3 is a thermal equivalent circuit diagram explaining the present invention in detail.・Ceramic heater (electric heater) ・First flange, handle, iron tip member, hole, iron tip, split groove, taper, fixed pipe, holding part, flange-like locking part 18...flange member 1 day ... Second flange 20 ... Fastening member

Claims (2)

[Claims] (1) A rod-shaped electric heater, a cylindrical portion that fits into at least the built-in portion of the electric heater, and a hole with a bottom that presses the tip end surface of the electric heater in the axial direction are bored, and the iron tip is attached to the tip of the hole. an iron tip member that is provided and has a taper formed on the outer periphery of the cylindrical portion; a restraining portion that abuts the taper of the iron tip member; and a flange-shaped lock that extends toward the base side of the cylindrical portion. a fixed pipe having a part, an axial groove provided in a part of the tip member that corresponds to the holding part and on the base side thereof, and a first pipe provided integrally with the base part of the electric heater. An electric iron having a flange, a handle supporting the first flange, and fastening means for tensioning between the first flange and the flange-like locking part. (2) The fastening means includes a flange member having a second flange that jointly holds the first flange with the handle, and a fastening member that tightens the tip of the flange member and the flange-like locking part. The electric iron according to paragraph 1, comprising: