JPH0344647B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention provides a housing for a digital thermometer;
Regarding its manufacturing method.

<Prior art> The housing of a digital thermometer is a flat cylinder with one end open and the other end transformed into a thin cylinder to attach a temperature sensor, and one side of the flat cylinder is fixed by inserting it inside from the open end. It has a temperature display window that allows you to see through the digital temperature display section using a liquid crystal device.

<Problems to be solved by the invention> Conventionally, a housing having a temperature display window opening,
The see-through window panels that fit into the window openings are each molded separately from plastic, and the window panels can be directly fitted into the window openings from the outside, or an O-ring can be fitted around the outer periphery of the window panels and the window panels can be fitted from the outside into the window openings. Then, the outer periphery of the window board and the inner periphery of the window opening are fixed with adhesive. However, this is not only time-consuming, but when the product is immersed in alcohol for disinfection, the alcohol penetrates between the window plate and the window opening and damages the electronic circuit inside the thermometer. It becomes useless.

<Means for Solving the Problems> Therefore, the present invention includes an outer shell having a temperature display window opening as a housing of a thermometer, and a see-through window plate protruding from the surface that fits into the temperature display window opening of the outer shell from the inside of the outer shell. Consisting of a cylindrical partial inner shell,
The outer shell is characterized by fitting a transparent window plate into the temperature display window opening from the inside and molding it outside the partial inner shell. The partial inner shell is first molded, and this partial inner shell is placed in the mold of the thermometer housing, and the see-through window plate is fitted into the temperature display window opening forming part of the mold. An outer shell with a temperature display window opening is formed outside the inner shell by injecting plastic, and as the outer shell contracts as it cools, the inner shell is tightened from around the circumference to secure the two shells together. It is characterized by sealing by tightening the see-through window plate from around the inner periphery.

<Function> According to the present invention, an outer shell is formed outside the partial inner shell having a transparent window plate protruding from the surface thereof, and the transparent window plate is fitted from the inside of the outer shell into a temperature display window opening provided in the outer shell. There is.

<Example> In the drawings, 1 is a fully molded housing, which has an outer shell 2 and a transparent window plate 3 that fits into the temperature display window opening 2' of the outer shell 2 from inside the outer shell, and the window plate is visible from the outside. It consists of a partial inner shell 4 that can only be seen 3. The term "partial inner shell" refers to the fact that the inner shell, unlike the outer shell, does not cover the entire housing.

The partial inner shell 4 may be entirely cylindrical, or, as shown in FIG. 2, may have crotch-shaped notches on the opposed flat surfaces 4a and 4b, and the cylindrical portion 4' may be only partially formed. The transparent window plate 3 is often thickened and protrudes from one flat surface.

In the present invention, this partial inner shell 4 is primarily molded with, for example, butadiene-styrene resin, and this partial inner shell is fitted into a core 6 to be inserted into the cavity of a mold 5 for molding the housing 1, and then inserted into the cavity. The outer shell 2 is molded from a suitable resin that shrinks as it cools, such as polyphenylene oxide (PPO: shrinkage rate per unit length of about 0.5%). Figures 3 and 4 show the state in which the core 6 with the partial inner shell 4 fitted is inserted into the mold 5. Molten resin for molding the outer shell is injected from the gate 7, and the partial inner shell 4, core 6 and Filling the space 8 created between the inner surfaces of the mold 5 with molten resin,
The outer shell is molded after waiting for the resin to cool.

In this case, the surface of the transparent window plate 3 protruding from the surface of the partial inner shell is one size smaller than the transparent window plate protruding from the inner surface of the mold 5, leaving the peripheral edge 3' as shown in an enlarged view in FIG. The projecting part 5' is brought into close contact with the projecting part 5' to prevent the resin for molding the outer shell from entering between them, and when molded, the surface peripheral part 3' of the transparent window plate and the inner part are formed as shown in FIGS. 5 and 6. The area protruding from the shell 4 is covered and surrounded with a resin for molding the outer shell, and a temperature display window opening 2' of the outer shell is formed at the same time. As mentioned above, the resin for molding the outer shell contracts as it cools, so the shrinkage tightens the inner shell part from around it, fixing both shells tightly, and also tightens the part of the transparent window plate that protrudes from the surface of the inner shell part. Tighten to ensure a secure seal. In addition, when molding the outer shell, if a partial inner shell having an appropriate temperature, for example, around 100°C, is fitted into the core and inserted into the mold immediately after molding, the temperature in the space 8 of the mold 5 will be high. The flow of the outer shell molding resin improves, and at the same time it blends in with the surface of the partial inner shell, increasing the adhesion effect between the partial inner shell and the outer shell molded thereon.

<Effects> As is clear from the above, the housing of the present invention has a reliable seal between the temperature display window opening and the transparent window plate that closes it, so even if it is immersed in an alcohol solution, alcohol will not enter the inside of the thermometer. Intrusion can be completely prevented.

Furthermore, during manufacturing, the partial inner shell and outer shell are molded individually, but since the outer shell is molded on top of the partial inner shell, it requires a lot of work such as fitting and fixing a see-through window plate into the temperature display window opening of the outer shell afterwards. is not necessary, and products with a reliable seal between the temperature display window opening and the transparent window plate can be produced with high efficiency.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the housing of the digital thermometer according to the present invention, Fig. 2 is a perspective view of a partial inner shell, and Fig. 3 is a longitudinal cross-section of the core and the partial inner shell inserted into a mold for forming the outer shell. Figure 4 is a cross-sectional view of the same as above,
Fig. 5 is an enlarged longitudinal sectional side view of the main parts of the molded housing, and Fig. 6 is an enlarged longitudinal sectional front view.
1 is a housing, 2 is an outer shell, 2' is a temperature display window opening, 3 is a transparent window plate, 4 is a partial inner shell, 5 is a mold, 6
indicates the core.

Claims (1)

[Scope of Claims] 1. A digital thermometer housing equipped with a transparent temperature display window, comprising: an outer shell having a temperature display window opening; and a transparent window plate that fits into the temperature display window opening of the outer shell from inside the outer shell. The digital type is composed of a cylindrical partial inner shell that protrudes from the surface, and the outer shell is molded outside the partial inner shell by fitting a see-through window plate into the temperature display window opening from the inside. Thermometer housing. 2. A cylindrical partial inner shell having a transparent window plate protruding from the surface is primarily formed, and this partial inner shell is housed in a mold of the thermometer housing, and the transparent window plate is fitted into the temperature display window opening forming part of the mold. Then, plastic that shrinks as it cools is injected into the mold to form an outer shell having a temperature display window opening outside the inner shell, and the inner shell is tightened from around the inner shell as it shrinks as the outer shell cools. A method for manufacturing a housing for a digital thermometer, characterized by fixing both shells and tightening a see-through window plate around the inner periphery of a temperature display window opening for sealing.