HK1017071B - Process for producing a protective cap for an infrared radiation thermometer that can be introduced into a body cavity - Google Patents

Description

Method for manufacturing protective cap of infrared radiation thermometer capable of being inserted into human body cavity

Technical Field

The invention relates to a method for producing a funnel-shaped protective cap which is suitable for fitting on a probe of an infrared radiation thermometer which can be inserted into a human body cavity for measuring the temperature of the auditory canal and which has a tubular body made of plastic, which is open at one end and closed at the other end by a window film which is transparent to infrared radiation.

Background

Body temperature may be measured with an electronic radiation thermometer, among other methods. Generally, such radiation thermometers comprise a housing with a window transparent to the radiation, an internal optical system, and an infrared sensor cooperating with a setting device. The radiation transparent window is used to enclose the interior of the radiation thermometer housing to protect the optical system and sensors from contamination and damage. To determine the body temperature of a person, the front end of the thermometer is inserted into the ear. Infrared radiation emitted from the tympanic membrane and ear canal enters the thermometer through the window and impinges on the infrared sensor through the optical system or an optical waveguide and an interference filter. As a result of the temperature increase in the sensor, a voltage is output, from which the temperature of the radiation can be determined by means of a setting device.

As mentioned above, a protective cap for the thermometer tip is additionally provided for covering the ear canal probe of an infrared radiation-sensitive ear drum thermometer, which protective cap is known, for example, from EP-B-0201790. The protective cap not only serves to protect the infrared window but also to prevent diseases from being transmitted to the user, and this is done by attaching a new protective cap before each temperature measurement if the body temperature of different persons is measured.

The protective cap of the type described in EP-B-0201790 has a film made of polypropylene or polyethylene which is transparent to infrared radiation. The part with the film is an injection moulded part.

Since such protective caps are generally disposable items that are removed and discarded after use in order to attach a new protective cap for the next temperature measurement, it is desirable that such protective caps be inexpensive items. The cost factor for manufacturing such a protective cap is not the material cost but the cost of the manufacturing process. Conventionally, such a cap is formed by injection molding a plastic material into a tubular body and then closing an open end of the body with a window film which is transparent to infrared radiation. US-5293862 is a reference to such a protective cap made by an injection moulding process.

EP-A-0589212 and EP-A-0637430 disclose flat protective caps comprising two or three films laminated together. There is a hole in the center of the first film. The second film is transparent to infrared radiation and has its corners welded to the first film. The flat protective cap can be shaped as a funnel to match the outer shape of the ear canal probe only when the user places the flat protective cap on the ear canal probe of the infrared radiation thermometer and presses the second film layer, which is transparent to infrared radiation, through the hole in the first film layer with the end of the ear canal probe. When the protective cap is removed from the ear canal probe after the measurement, the protective cap is not funnel-shaped.

Disclosure of Invention

Starting from the above-mentioned prior art and the known methods of manufacturing such protective caps, it is an object of the present invention to provide a manufacturing method which makes the manufacture of funnel-shaped protective caps more economical and which is suitable for use with a variety of different materials.

To achieve the above object of the present invention, there is provided a method for manufacturing a funnel-shaped protective cap adapted to be mounted on an ear canal thermometer of an infrared radiation thermometer, the protective cap having a body made of plastic, one end of which is open, and the other end of which is closed with a window film that is transparent to infrared radiation, comprising the steps of: punching a hole in a sheet-like or film-like or belt-like or plate-like body material for forming the body; covering at least the area of the hole in the body material in which the hole is punched with a window film made of a plastic material which is transparent to infrared radiation, and joining the window film to the body material in an immovable manner; forming the composite into a protective cap; and an applicable protective cap, which is machined to the required size.

There is also provided a method for manufacturing a funnel-shaped protective cap adapted to be mounted on an ear canal thermometer of an infrared radiation thermometer, the protective cap comprising a tubular body made of plastic and open at one end and closed at the other end by a window membrane permeable to infrared radiation, the method comprising the steps of: a sheet-like or film-like or belt-like or plate-like body material for forming the body is thinned by pressing it in a region intended to form a cooperative work with the window film; forming the main body material into a protective cap by a deep drawing or stamping process; and a protective cap which can be used, and machining the protective cap to a required size.

According to the method of the invention, the body is made of a film, a rolled tape or a sheet of body material, and is provided with a window film. This material can be continuously fed into a production line where the punching, forming and cutting processes are performed sequentially. This double layer structure provides a thermal insulation layer on the outer layer while forming the window. By using the method, a plurality of protective caps can be quickly and continuously produced on a production line. It does not require the known type of cooling time to be allowed during injection molding of the part. Alternatively, the body material may be covered completely with a layer of foamed plastic film, or some plastic film with entrapped air, and then thinned by hot stamping or pressing to improve its transmission of infrared radiation.

When a flexible strip of material is used, the strip may be unwound from a supply roll, typically a continuous strip wound around a supply roll. However, there is also the possibility of feeding the material from a stack of materials (at least for the body) and then feeding it continuously to the subsequent processing stations.

According to a first method of manufacturing the protective cap, the first step comprises punching a hole in the material of the body with a punch. The holes are then formed into the open end of the body and the body is then used to form a protective cap.

As described initially with respect to the prior art, such protective caps have a film window and are desirably as thin as possible and transparent to radiation within the relevant measurement range. After the holes have been punched in the body material, the windows are shaped in a second step which comprises feeding a window film, typically of thickness 20-50 μm, and then joining the punched body material to the window film by welding and/or by adhesive bonding.

It is not necessary to have a large surface area for the body material and the membrane material to be joined together, but it is sufficient to join them in the edge area of the hole. It is important that the thickness of the film is the same for all protective caps; any difference in thickness affects the measurement results of the radiation thermometer equipped with the protective cap using the window film. Particularly when a strip-like film material is fed, it is possible to lay the film uniformly, smoothly and surely on the body material because two materials having a relatively large surface area are stacked and joined on a plane.

It is clear that not only one row of holes may be punched in the body material, but several rows of holes are punched, usually in a direction perpendicular to the production line. The thickness of the film as the host material is in the range of 0.4 to 0.8 mm. Typically, the host material is a plastic, particularly polyethylene or polystyrene.

After the body material and the window film are joined together in the second process step, the pre-processed fed blank is fed to a third processing station, a protective cap is formed by deep drawing, and each punched hole is deep drawn within a range capable of simultaneously performing all punching holes. Finally, the piece of material, which also carries the deep-drawn body, is taken to a fourth step, where each individual protective cap is dimensioned and cut off.

Experience has shown that providing an inspection step after the incoming blank is formed, but before it is machined to the desired dimensions, can speed up the production process, particularly when only one continuous row of punched holes is present in the strip or sheet material on the production line. Considering that the forming of the fed blank after the body and the film are joined together is a critical step, and the effect of this step on the quality cannot be disregarded, an inspection step should be arranged before the fed blank is worked to the desired dimensions, in which the penetration of the film material is inspected on an inspection bench and those film materials which do not meet the penetration requirements within the measurement accuracy range which has to be met are marked. In the subsequent production process, those blanks which do not meet the quality requirements are no longer machined to the required dimensions, but rather are removed from the final machining step.

The method described above is not only suitable for processing materials in the form of films or sheets, but is also suitable for thermally insulating materials, such as foams. Experience has shown that a protective cap made of a material with good thermal insulation properties, including foam, is very advantageous in avoiding measurement errors due to the influence of external heat when measuring body temperature. It will be appreciated that insulating the portion of the body in close proximity to the window, and thus in close contact with the body cavity (e.g. ear canal), in this manner reduces the amount of heat transferred to the infrared optical system or keeps the amount of heat transferred to a negligible extent affecting the temperature measurement. Since such a protective cap reduces the heat input, cooling of the auditory canal or the like is also simultaneously eliminated. This further reduces the discomfort for the user, since the thermometer with such a protective cap does not cool the user's ear, but rather warms him. Furthermore, the heat-insulating means may be a flexible member which is more comfortable for the ear than a rigid, non-elastic material or a protective cap wrapped with such a material. Another particular advantage of such a protective cap is that it can be used in combination with a medical thermometer having a small temperature measuring probe. If the protective cap has at least two sizes, the medical thermometer with the small temperature measuring head can measure the body temperature for both adults and children. However, it is also possible to make the protective cap particularly flexible and resilient with a heat-insulating material, so that it is suitable for use in the auditory canal of both adults and children, despite differences in the dimensions of the auditory canals.

The foam-like insulating material has the advantage that the insulating properties can be adjusted beforehand, in particular by suitably selecting foams with different cell sizes and thus different air percentages, or foams with open or closed cells (preferably foams with closed cells). Furthermore, it is also possible to deform the foam by stamping, in particular with irreversible hot stamping, so that certain edge regions of the body can be thinned (for example in the region of the hole in which the film is applied) or thickened by gasketing (for example on the lower flange on the side opposite the window opening of the disposable protective cap).

Although the above description specifically describes a method of manufacturing a protective cap starting from a body material and a film material joined together, there is another continuous manufacturing method of manufacturing a protective cap with a film-like window from only a single material. The stamping procedure mentioned in the first method in the above description is a manufacturing step which can be used for this purpose, starting from a well-worked body material, through which infrared radiation can better penetrate after a suitable thinning, and can be stamped in such a way that the body and the window film are formed by the whole body.

Thinning the starting material of the window area is typically done in several separate hot or cold stamping forming steps. The thinning of the material in the region of the window film has the effect of avoiding potential natural radiation by reducing the thickness of the film, which would otherwise adversely affect the error of the radiating elements on the detecting means of the radiation thermometer, and also contributes to the thermal radiation emitted by the human body.

In the latter method, the step of reducing the area of the starting material corresponding to the window film to the desired size is usually carried out in a deep drawing step, so that it is possible to verify that the desired thickness has been reached, otherwise the final deep drawing affects its thickness if it had been drawn to the desired size in the previous step.

It is obvious to a person skilled in the art that the second method can also be performed in a variety of different procedures within the scope of the first method described above with reference to the above.

Drawings

Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic cross-sectional view of a protective cap with a window membrane;

FIGS. 2A and 2B are schematic process sequence diagrams for fabricating the same protective cap as shown in FIG. 1; and

figure 3 is a schematic view of a part of a production line for manufacturing protective caps by means of stamping starting materials.

Detailed Description

Due to hygienic requirements, the protective cap 1 is mounted on the front end of a medical infrared radiation thermometer, and serves as a thermal insulation in addition to protecting the access window of the radiation thermometer from contamination. In order to measure the temperature of the human body, the protective cap 1 is mounted on a radiation thermometer (not shown in the figure) and its front end 2 is then inserted into the ear canal (not shown in the figure) in order to measure the emitted infrared radiation.

The cap has a tubular body 3, the lower end 4 of the body 3 being open. At the upper or front end 2 there is an aperture 5 forming a radiation receiving window and suitably surrounded by a rigid ring 20.

As is clear from the cross-sectional view of fig. 1, the protective cap 1 is of a double-layer structure comprising a layer of host material 6 and a layer of film material 7. In the representative fig. 1, the body material 6 forms a relatively dimensionally stable body 3, while the film material 7 is attached to the entire inner surface of the body 3 and held in tension over the aperture 5, thereby forming a window through which radiation can enter.

In order to enable the economical continuous manufacture of the above-described protective caps 1 on a production line, a suitable strip 22 of the body material 6 is taken from a supply roll 8 and fed to the punching station 9, as shown in fig. 2A. The host material fed is typically a polyethylene or polystyrene film having a thickness in the range of 0.4-0.8 mm. Holes 5 are continuously punched in the strip-like body material at a punching station 9, which holes 5 provide windows for the radiation to enter in the finished protective cap 1.

Although the holes 5 in the body material 6 are relatively far from each other in fig. 2A, it should be clear that the holes may also be very close, preferably by punching several holes simultaneously in one punching operation, or by punching several rows of holes 5 in a direction perpendicular to the production line (indicated by arrow 10). As schematically shown in fig. 2A and 2B, a number of drive rollers 11 are arranged along the production line, of which a portion at the end of the production line is in contact with the edge of the material 6 only.

After the holes have been punched in the first manufacturing step, a second station follows in which a strip 23 of window film 7, released from the second feed roll 12, is applied to the upper surface 21 of the body material 6. Generally, a polyethylene or polypropylene film having a thickness of 20 to 50 μm is used as the window film. The film material 7 is pressed against the body material by a pressing roller 13 and the two are welded or bonded together by heating. The composite comprising the host and film materials 6, 7 is then fed to a deep drawing station 24, schematically shown in figure 2B, where the area around each hole 5 is deep drawn into a protective cap as shown in figure 1.

After deep drawing, in a fourth step following the third step, the strip 22 is inspected at a fourth station. For this purpose, an infrared radiation source 15 is provided at the fourth station 14, which emits radiation in the wavelength range relevant for the measurement of the temperature onto the individual openings 5 covered by the film material 7. A sensor 16 is provided below the web 22 for detecting the amount of penetrating radiation, and if the penetration of the window film 7 does not meet the quality requirements, a mark is made on the protective cap 1 and no further processing is performed at the last processing station 17, at which the protective cap 1 is cut from the web and processed to the required size.

Although in the process sequence of fig. 2A to 2B the film material 7 is laid on the side of the body material 6 forming the inside of the protective cap 1 shown in fig. 1, it will be appreciated that the film material 7 forming the window 7 may also be laid on the opposite side, i.e. on the lower surface of the body material 6 in fig. 2A and 2B, which forms the outside of the protective cap 1 at a later stage, as a result of which a smooth outer surface is obtained.

Fig. 2A and 2B show a process sequence for forming a protective cap from two webs 22, 23, i.e., a body material 6 and a film material 7, while fig. 3 schematically shows a process sequence for continuously manufacturing a protective cap from a single web according to the second aspect of the present invention. According to fig. 3, a body material 18 having good stamping and/or forming properties is fed in. On the one hand, the block is of polyethylene material suitable for making a body which is dimensionally stable, and on the other hand, it is also transparent to infrared radiation in the temperature range of the body being measured. The piece of body material 18 is then fed to a stamping station 19, which shapes the material, typically after several successive stamping steps, to produce individual protective caps 1 shaped from the body material 18 at the output end of the stamping operation. In this protective cap 1, its front end 2 with the window 7 is directed downwards. In the above-mentioned stamping step 19, the protective cap 1 can be shaped so that the walls of the various parts have different thicknesses, depending on the particular requirements imposed on the protective cap 1. The starting material 18 is then shaped in the region of the window 7 as a very thin film, forming the window film 7.

It is obvious that in the stamping station 19 the starting material 18 can first be shaped by stamping comprising several process steps. In a subsequent deep-drawing step, the tubular or funnel-shaped protective cap shown in fig. 1 is then produced as described for fig. 2B. According to fig. 2B, the deep drawing is followed by an inspection step and a step of machining the individual protective caps to the finished dimensions.

Claims (23)

1. A method for manufacturing a funnel-shaped protective cap (1) suitable for mounting on an ear canal thermometer of an infrared radiation thermometer, which protective cap has a body (3) made of plastic, which is open at one end and closed at the other end by a window membrane (7) which is transparent to infrared radiation, comprising the following steps:

punching a hole (5) in a sheet-like or film-like or belt-like or plate-like body material (6) for forming the body (3);

covering at least the area of the holes (5) in the punched body material (6) with a window film (7) made of plastic material which is transparent to infrared radiation and is immovably connected to the body material (6);

forming the composite into a protective cap (1); and

for the applicable protective cap, the protective cap (1) is machined to its required dimensions.

2. A method according to claim 1, wherein said holes (5) are punched in said body material (6).

3. A method according to claim 1, wherein the punched body material (6) and the window film (7) are immovably joined by welding.

4. A method according to claim 1, wherein the punched body material (6) and the window film (7) are immovably bonded together by means of an adhesive.

5. A method according to claim 1, wherein the body material (6) is discharged from a first supply roll (8) and is subsequently punched in a first step.

6. A method according to claim 1 or 5, wherein the window film (7) is unwound from a second supply roll (12) and joined to the punched body material (6) in a second step.

7. A method according to claim 5, characterized in that the body material (6) is a continuously fed strip, the holes (5) being made in a first step, and the manufactured protective caps being cut from the strip in a subsequent step after the forming step.

8. A method according to claim 1, characterized in that the incoming host material (6) is a film (7) having a thickness in the range of 0.4-0.8 mm.

9. A method according to claim 1, characterized in that the thickness of the incoming window film (7) is in the range of 20-50 μm.

10. A method as claimed in claim 1 or 6, characterized in that the window film (7) is applied to the upper surface (21) of the body material (6) to form an inner coating on the protective cap following the forming process.

11. A method according to claim 1, characterized in that the above-mentioned body material (6) used is a film made of plastic, in particular polyethylene or polystyrene.

12. A method as claimed in claim 1, characterized in that the window film (7) used is made of a material selected from the group consisting of polyethylene and polypropylene.

13. Method according to claim 1, characterized in that said protective cap (1) is deep-drawn in a third step.

14. A method according to claim 1, characterized in that the above-mentioned body material (6) used is a heat-insulating material.

15. A method according to claim 14, wherein the insulating material used is a foam.

16. A method according to claim 1, 14 or 15, wherein said forming step is a stamping operation.

17. The method of claim 1, wherein an inspection step is performed prior to said machining to a desired dimension.

18. The method according to claim 17, wherein the inspection step is carried out to inspect the infrared radiation transmission properties of the window film (7) in the relevant temperature measurement range.

19. A method according to claim 1, characterized in that an annular reinforcement ring (20) is formed along the edge of the hole covered with the window film.

20. The method of claim 19, wherein said annular reinforcing ring (20) is formed during said forming step.

21. A method for manufacturing a funnel-shaped protective cap (1) adapted to be mounted on an ear canal thermometer of an infrared radiation thermometer, comprising a tubular body (3) made of plastic, open at one end and closed at the other end by a window membrane (7) transparent to infrared radiation, the method comprising the following steps: a thin plate-like or film-like or belt-like or plate-like body material (6) for forming the body (3) is thinned by pressing it in a region intended to be formed to cooperate with the window film (7); forming the main body material (6) into the protective cap (1) by a deep drawing or pressing process; and a usable protective cap, machining the protective cap (1) to a desired size.

22. The method of claim 21 wherein said predetermined area is thinned in a plurality of stamping steps.

23. A method as claimed in claim 22, characterized in that the thinning of the predetermined area to the final thickness of the window film (7) is performed as part of a deep drawing or punching process.