JPS632455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a probe for an electronic thermometer, more specifically, a probe that incorporates a heat-sensitive element such as a thermistor and is inserted into the armpit or under the tongue to detect body temperature using the heat-sensitive element. The present invention relates to a probe of an electronic thermometer that is connected to a thermometer body that measures the element constant of a heat-sensitive element that changes in response to temperature changes to display body temperature.

As shown in FIG. 1, the conventional probe of this type of electronic thermometer has a heat-sensitive element 2 such as a thermistor attached to one end of a protective tube 4 made of a soft heat insulating material such as polyethylene. The heat-sensitive element 2 was surrounded by a cap 6 made of epoxy resin or alumina, and the lead wire 1 of the heat-sensitive element 2 was a single wire. That is, by making the lead wire 1 a single wire, the amount of heat entering and exiting through the lead wire 1 is reduced to reduce measurement errors, and the heat capacity near the heat sensitive element 2 is reduced to increase response speed. On the other hand, the protective tube 4 has flexibility so that it can be easily inserted under the tongue or under the armpit, but due to this flexibility, the lead wire 1 of the heat-sensitive element 2 is also bent. Since the lead wire 1 is a single wire, the lead wire 1 is easily broken when bent.

The present invention has been made in view of the above-mentioned drawbacks, and its main purpose is to provide a protective tube that is flexible and easy to use;
Moreover, the purpose is to provide a probe whose lead wires will not break, and other purposes include:
The object of the present invention is to provide a probe with little measurement error and high response speed.

Embodiments of the present invention will be described below based on the drawings. The electronic thermometer probe according to the present invention basically has a heat sensitive element 2 such as a thermistor with a single lead wire 1 protruding from its rear end, and is electrically connected to the tip of the lead wire 1 of the heat sensitive element 2. A stranded connecting wire 3, a protective tube 4 which is a tube made of a soft heat insulating material and which wraps around the lead wire 1 and the connecting wire 3, and a protective tube 4 inserted into the front end of the protective tube 4 and connected to the lead wire 1. A holding tube 5 made of a hard thermally insulating material that covers approximately the entire length of the lead wire 1 including the connection part with the wire 3; The cap 6 is made of a heat conductive material. This embodiment shows an example in which the thermal element 2 is a thermistor. As shown in FIGS. 2 and 3, a heat sensitive section 7 with a built-in thermistor 2 is provided at the tip, and the thermistor 2 is provided behind the heat sensitive section 7.
The protective tube 4 that covers the lead wire 1 is continuous, and the rear end of the protective tube 4 is continuous to the protector part 8.
The heat sensitive part 7, the protection tube 4, and the protector part 8 are arranged in a straight line. A cord 9 having a plug 10 at one end extends from the rear end of the protector portion 8.
This plug 10 is connected to a thermometer main body (not shown), and the change in resistance value of the thermistor 2 housed in the heat sensitive part 7 is measured by the thermometer main body, and the corresponding temperature is displayed. Thermistor 2 lead wire 1
are a pair of single wires with a diameter of about 0.2 mm that protrude from the rear end of the thermistor 2. A cap 6 made of a metal with good heat conductivity such as copper or aluminum is placed around the thermistor 2. The cap 6 has a closed front end with a rounded convex surface and an open rear end. A lead wire 1 protruding from the thermistor 2 passes through a holding cylinder 5 made of a hard heat insulating material such as polyacetal. Holding tube 5
As shown in FIG. 4, a pair of half bodies 11a,
11b are combined so that the outer periphery of the cross section is approximately circular. That is, both halves 11a and 11b constituting the holding cylinder 5 are each approximately semi-cylindrical, and the fitting protrusion 12 extends from the abutting surface of one of the halves 11a to approximately the entire length of the holding cylinder 5 in the axial direction. A fitting protrusion 12 provided on the other half body 11a is provided on the abutting surface of the other half body 11b.
A fitting groove 13 that fits into the holding cylinder 5 is formed over substantially the entire length of the holding cylinder 5 in the axial direction. Both halves 11a, 11b
A pair of through holes 1 are formed on both sides of the fitting protrusion 12 in the assembled state, and the through holes 1 extend through the holding cylinder 5 in the axial direction.
4 is formed. Each lead wire 1 of the thermistor 2 is inserted into each of the through holes 14, and both lead wires 1 are insulated by the fitting protrusion 12. Through hole 14
As shown in FIG. 3, the diameter is thinner at the front end and thicker at the rear end. The lead wire 1 is electrically connected to the connecting wire 3 made of twisted wire at the large diameter portion of the through hole 14. The lead wire 1 and the connection wire 3 may be connected by welding or soldering, or may be fixed using a tube-shaped female terminal 15, as shown in FIG. The connecting wire 3 is wrapped in a sheath 16 of a flexible heat insulating material such as soft vinyl chloride. The rear end of the holding cylinder 5 also covers the front end of the sheath 16, and the surface that comes into contact with the sheath 16 has a claw 17 that bites into the sheath 16.
is provided in a protruding manner to prevent the covering 16 from shifting. Thereby, even if an external force is applied to the connecting wire 3, the connecting wire 3 will not move, and as a result, no unreasonable force will be applied to the thermistor 2. An outer flange 18 is formed at the front end of the holding cylinder 5 . The protective tube 4 is made of a flexible, soft heat insulating material such as polyethylene, and has its front end abutted against the outer flange 18 and covers approximately the entire length of the retaining tube 5 and the covering 16 of the connecting wire 3. It continues to the protector part 8. Outer flange 18 on the outer peripheral surface of the holding cylinder 5
A plurality of locking ribs 19 are provided protrudingly spaced apart along the axial direction of the holding cylinder 5 at the rear of the holding cylinder 5 . The tip of the locking rib 19 is sharp and bites into the protective tube 4 to prevent the protective tube 4 from shifting in the axial direction. In order to enhance the effect of preventing displacement of the protective tube 4, the rear end of the cap 6 is squeezed at a position facing the locking rib 19 via the protective tube 4, and the protective tube 4 is pressed against the locking rib 19. There is. By tightening the cap 6 in this way,
The cap 6 is engaged with the outer flange 18 of the holding cylinder 5, thereby preventing the cap 6 from coming off. A projection 20 with a tapered tip projects from the front end of the fitting projection 12 of the holding cylinder 5. The tip of this protrusion 20 contacts the rear end of the thermistor 2 to lift the thermistor 2 from the holding cylinder 5, thereby reducing the heat capacity around the thermistor 2, and also pushes the thermistor 2 forward so that the thermistor 2 is inside the cap 6. Position it so that it is located at the front end. As a result, the distance between the thermistor 2 and the cap 6 becomes smaller, and heat transfer from the cap 6 to the thermistor 2 can be carried out quickly. A space 21 is formed in a portion surrounded by the inner circumferential surface of the cap 6, the outer circumferential surface of the thermistor 2, and the front end surface of the holding cylinder 5, and is designed to speed up heat transfer between the cap 6 and thermistor 2 and increase response speed. This space 21 is filled with a sealing material 22 made of a material with good heat conductivity such as epoxy resin or silicone resin. This encapsulant 22 is hardened after the cap 6 is attached. By the way, the front end of the cap 6 is provided with a small hole 23 that passes through the inside and outside of the cap 6. When the cap 6 is placed over the thermistor 2, air inside the cap 6 and excess encapsulant 2 are removed.
2 is discharged from the cap 6 through this small hole 23. As a result, the encapsulant 22 can be filled into the cap 6 without any gaps, and the pressure inside the cap 6 does not increase when the cap 6 is attached, improving workability. The encapsulant 22 that protrudes to the outside may be removed as appropriate.
As mentioned above, the protective tube 4 and the holding cylinder 5 are formed of a heat insulating material, and the cap 6 and the encapsulant 2 are made of a heat insulating material.
2 is formed of a heat conductive material, and the thermistor 2
Since the thermistor 2 is suspended from the holding cylinder 5 by a protrusion 20 protruding from the holding cylinder 5, the thermistor 2 is surrounded entirely by a heat conductive material, thereby increasing the response speed to external thermal changes. The one shown in FIG. 5 is another embodiment in which instead of providing a small hole 23 in the cap 6, a relief groove 2 is provided on the outer periphery of the outer flange 18 of the holding cylinder 5 along the axial direction of the holding cylinder 5.
4 was formed. A plurality of escape grooves 24 are provided along the circumferential direction of the outer flange 18, and
Air inside the cap 6 and excess mounting medium 22 during installation.
is discharged into this relief groove 24. After installing the cap 6 in this way, the rear end of the cap 6 is squeezed and pressed against the protective tube 4, so that the rear end of the relief groove 24 is closed after the cap 6 is installed, so that even if the probe is immersed in alcohol, the probe will remain inside the cap 6. It is something that it cannot infiltrate. Note that it is a matter of course that other elements than the thermistor may be used as the heat-sensitive element 2.

As described above, the present invention uses a single wire as the lead wire of the heat-sensitive element as an electric wire used to connect the heat-sensitive element to the thermometer body, and connects a twisted wire connection wire to this lead wire, and connects the lead wire and the connection wire. is wrapped in a protective tube made of a soft material, and approximately the entire length of the lead wire, including the connection part between the lead wire and the connecting wire, is wrapped in a holding tube made of a hard material. It is easy to insert under the tongue or under the tongue, and even if the protective tube is bent, the connecting wire is a stranded wire and the lead wire is wrapped in a hard holding tube.
It has the advantage of requiring less insulation. Further, since the lead wire is a single wire, there is an advantage that there is little heat entering or exiting through the lead wire, and a probe with small measurement error and fast response speed can be provided. Furthermore, since the heat-sensitive element is surrounded by a hard material, it has the advantage of being resistant to external impacts. Furthermore, a protrusion is provided at the front end of the holding cylinder, and the rear end of the heat-sensitive element is brought into contact with the tip of the protrusion to position the heat-sensitive element at the front end inside the cap, and a thermally conductive material is provided in the space between the cap and the heat-sensitive element. If the heat-sensitive element is filled with a mounting medium such as a good silicone resin, the heat-sensitive element will float from the holding cylinder or protective tube made of a thermally insulating material, and the entire periphery of the heat-sensitive element will be surrounded by the cap and the heat-conductive material of the mounting medium. This has the advantage that heat transfer to the heat-sensitive element is performed smoothly, and as a result, response characteristics to changes in body temperature are improved. Also, if the cap has a small hole that penetrates inside and outside the cap,
When the cap is installed, air inside the cap and excess mounting medium filled in the cap are discharged to the outside of the cap through the small holes, filling the cap with the mounting medium without any gaps and improving heat transfer from the cap to the heat-sensitive element. This has the advantage that performance is improved, and since the pressure inside the cap does not increase when the cap is installed, the cap is easy to install and workability is good. A plurality of locking ribs with pointed tips are provided on the outer circumferential surface of the front end of the holding cylinder, spaced apart along the axial direction, and protrudingly provided, and the rear end of the cap is placed over the outer circumference of the locking ribs via a protective tube. In the case where the rear end is squeezed along the outer circumference of the protective tube, the protective tube is pressed against the locking rib by the cap, the locking rib bites into the protective tube, and the protective tube is positioned in the holding tube. This has the advantage of not only preventing the protective tube from coming off, but also ensuring reliable insulation between the cap and the lead wire.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a conventional example, FIG. 2 is a side view showing an embodiment of the present invention, FIG. 3 is a partial sectional view of the same, and FIGS. 4 a and b are A in FIG. -A sectional view, a BB line sectional view, FIGS. 5a and 5b are a partial sectional view showing another embodiment of the present invention, and a CC line sectional view in FIG. 1 is a lead wire, 2 is a heat sensitive element, 3 is a connection wire, 4
is a protection tube, 5 is a holding tube, 6 is a cap, 1
9 is a locking rib, 20 is a protrusion, 21 is a space, 22 is an encapsulant, and 23 is a small hole.

Claims (1)

[Claims] 1. A heat-sensitive element such as a thermistor having a single lead wire protruding from its rear end, a stranded connecting wire electrically connected to the tip of the lead wire of the heat-sensitive element, and a soft thermal insulating material. A protective tube that is formed by a tube that wraps around the lead wire and the connecting wire, and a hard thermally insulating tube that is inserted into the front end of the protective tube and that wraps approximately the entire length of the lead wire, including the connection part between the lead wire and the connecting wire. An electronic thermometer comprising a holding tube made of a material and a cap made of a hard heat conductive material that covers a heat-sensitive element and whose rear end is connected to the front end of a protective tube. probe. 2 A protrusion is provided at the front end of the holding cylinder, and the rear end of the heat-sensitive element is brought into contact with the tip of the protrusion to position the heat-sensitive element at the front end of the cap, and a thermally conductive material is provided in the space between the cap and the heat-sensitive element. The electronic thermometer probe according to claim 1, characterized in that the probe is filled with an encapsulant such as a silicone resin. 3. A probe for an electronic thermometer according to claim 2, characterized in that a small hole passing through the inside and outside of the cap is formed at a position facing the space on the inner circumferential surface of the cap. 4. A plurality of locking ribs with pointed tips are provided on the outer circumferential surface of the front end of the holding cylinder at a distance along the axial direction, and the rear end of the cap is placed over the outer circumference of the locking ribs via a protective tube, and the cap is 4. The electronic thermometer probe according to claim 1, wherein the rear end portion is narrowed along the outer periphery of the protective tube.