GB1564215A - Egg cooking indicators - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO EGG COOKING INDICATORS (71) I DUANE GEORGE CHAD WICK, of 555 East 3rd North, Logan, Utah 84321, United States of America, a citizen of the United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which is it to be performed, to be particularly described in and by the following statement: This invention relates to egg cooking indicators, that is devices for indicating the progress of a process of cooking of eggs and, in particular, for providing control of the preparation of boiled eggs.

Various devices have been proposed in the past as a means for governing the length of time for which an egg should be boiled.

Most of these known devices comprise timers which merely indicate when an egg has been immersed in boiling water for a period of time and it is merely assumed that when a pre-set time has expired the egg is cooked to the desired consistency. For this purpose, spring-wound clock timers, various hourglass type structures and many other devices have been developed. While these previously known timer-devices have been somewhat satisfactory, since based on prior experience, they frequently warn the user that the egg is cooked at least approximately to the extent desired, they do not allow the size of the egg, the temperature of the egg at the start of the cooking operation, the cooking temperature of the water, the altitude at which the water is being boiled, or other factors which affect the cooking time, to be considered.U S Patent Specification No 2 430 290 shows an instrument which, in use, is placed in the water in which an egg is to be boiled and which responds to temperature increases of the water so as to indicate, on a scale, the degree of cooking of an egg placed in the water for cooking purposes.

This instrument comprises a mercury thermometer firmly set into a transparent casing, the temperature-responsive end of the thermometer being surrounded by a suitable insulating material which fills the end of the casing. The insulating material keeps the mercury in the themometer from being heated too rapidly.

The present invention provides an improved form of egg cooking indicator which, in use, reacts to temperature increases of the water in which an egg is cooked, such that the degree of cooking of the egg can be determined by reading a scale incorporated in the instrument, and which also can be more easily constructed and more easily and reliably calibrated than is the case with instruments which have previously been made or proposed for this purpose.

According to one aspect of this invention an egg cooking indicator comprises a trans- parent tubular housing closed at both ends, an elongate thermometer located within the housing and having a temperatureresponsive part adjacent an end of the housing, a thermal insulating material surrounding such part of the thermometer and serving to reduce its rate of response to temperature change and an air space within the housing substantially surrounding the insulated part of the thermometer.

The invention also consists in a method of producing an egg cooking indicator, which comprises attaching a thermometer to a backing member, providing thermal insulation around a temperature-responsive part of the thermometer and affixing the thermometer to the backing member in a calibrated position, locating the backing member and the thermometer in a transparent tubular housing so that an air space substantially surrounds the insulated temperatureresponsive part of the thermometer, silvering the inside of the housing around the temperature-responsive part of the thermometer and closing the housing.

In accordance with preferred features of the indicator of the invention, the transparent tubular housing having both ends closed preferably is cylindrical and has a liquid (preferably a mercury) thermometer mounted therein. The reservoir end of the mercury thermometer, i.e. its temperatureresponsive part, desirably is mounted within an epoxy insulating material, preferably a resin material, which serves as a thermal mass heat sink. The thermometer and the epoxy or other insulating material are located within the housing so that the aforementioned air space is provided around the insulating material and thus also around the temperature-responsive part of the thermometer. A calibrated backing member is employed, preferably, which both provides the thermometer scale and also serves to position the thermometer as the epoxy is set therearound.By this arrangment, the thermometer and the epoxy resin are positioned within the housing. A portion of the housing adjacent the epoxy resin and thus adjacent the reservoir end, i.e. the temperature-responsive end, of the thermometer desirably is silvered on the inside, so as to prevent the thermometer from reacting in response to radiated heat energy. The calibrated backing member is provided with indicia thereon to cooperate with the liquid of the thermometer in indicating when desired degrees of cooking have been achieved for eggs of different sizes.

In order that the invention may be fully understood, a preferred embodiment of it is described below. by way of illustration, in conjunction with the accompanying drawings, in which: Figure 1 shows a perspective view of an egg cooking indicator of the invention, as positioned in a pan of water in which eggs are being cooked; Figure 2 shows a front elevational view of the egg cooking indicator of the invention; Figure 3 shows a vertical section taken on the line 3-3 of Figure 2; and Figure 4 shows a transverse section taken on the line 4-4 of Figure 2.

In the preferred embodiment shown, the egg cooking indicator of the invention is indicated generally at 10. As shown best in Figure 1, it can be positioned in a pan 11 containing water 12 in which one or more eggs are to be boiled. The indicator 10 includes a tubular housing 13. which is preferably made of glass and is cylindrical, having both of its ends closed. The housing 13 may be formed by closing the open end of a tube in which the other components of the indicator 10 have been positioned.

A mercury-in-glass bulb-tvpe thermometer 14 is located within the housing 13 by being affixed to a backing member. shown generally at 15. Upper side tabs lSa and lSb of the backing member 15 are bent forwardly from the backing member 15 so as to engage with and extend beyond opposite sides of the stem of the thermometer 14 into engagement with the inside surface of the wall of the housing 13. The narrow part of the backing member 15 between the side tabs 15a and 15b is bent forwardly as shown in Figure 3 over the top end of the thermometer 14. At a suitable place along the length of the thermometer 14, a pair of lower side tabs 15c and 15d are bent forwardly from the backing member 15 similarly so as to engage with opposite sides of the stem of the thermometer 14 and project past it into engagement with the wall of the housing 13.A long narrow central portion 15f of the backing member 15 extending down from between the lower side tabs 15e and 15d is bent to the rear away from the thermometer 14 and extends beyond the bulb end of the thermometer 14 into a sleeve 16, which is filled with an epoxy resin 17, as shown in Figure 3. The upper part of the backing member 15 between the upper and the lower side tabs is made just wide enough to fit within the housing 13, so that the respective edges of this upper part of the backing member 15 engage with the wall of the housing 13 on either side of the thermometer 14, whilst the projecting ends of the tabs 15a, 15b, 15c and 15d extend forwardly past the thermometer 14 so as to engage with the housing wall in front of the thermometer 14.So arranged, the assembly formed by the backing member 15 and the thermometer 14 fits snugly within the housing 13, although some vertical adjustment of the position of this assembly relative to the housing 13 can be made and the lower end of the thermometer 14, i.e. the bulb end of the thermometer, and the adjacent lower part of the narrow central portion 15f of the backing member 15 are potted in the epoxy resin 17, so that the sleeve 16, the epoxy resin 17 and the members bedded therein are held at a distance away from the wall of the housing 13. An air space 16a is thus formed between the sleeve 16 and the surrounding part of the housing 13. this air space 16a thus surrounding the part of the thermometer 14 which is insulated by the epoxy resin 17.

In order to ensure proper positioning of the thermometer 14 with regard to the cooking level indicia (shown best in Figure 2) on the backing member 15, the thermometer 14 is positioned on the latter between the tabs lSa-15d and is moved longitudinally to the proper position. The narrow portion forming the central upper tab 15e is then bent over the end of the thermometer 14, so as to prevent further longitudinal movement of it in the upward direction. The thermometer bulb and the long tab 15f are positioned in the sleeve 16. The epoxy resin 17 is then poured into the sleeve 16 whilst the thermometer 14 is held firmly against the tab 15e.The epoxy resin 17 is formed so as to have a dependent nipple 17a, so that if any bottom portion of the suspended backing should contact the housing 13 it will make only point contact with the insulating material 17 and no significant heat transfer will occur thereby. The indicator is made, however, so that the air space 16a is provided between the insulated temperature-responsive end of the thermometer 14 and the wall of the housing 13.

The indicia on the backing member 15 form a temperature-responsive gauge applicable to the cooking of eggs, as shown in Figure 2. As such, no conversion is required by the user from scales normally found on thermometers, i.e. Farenheit, centigrade, inches, mm, cm and so on.

Because the epoxy resin insulating material 17 is at one end of the thermometer 14 and consequently is positioned below the centre of the housing 13, the centre of gravity of the indicator device 10 is therefore below the centre of the housing 13.

Therefore because the housing 13 has a rounded bottom, the device 10 will always be self-righting in use. so that the indicia scale can be readily observed.

In addition to providing a scale and acting as a suspension member, the rigid backing member 15 also strengthens the thermometer stem so as to reduce the possibility of breakage if the unit is shaken, bumped or dropped.

The lower portion of the inside of the housing 13 is provided with a coating 18 of metallic silver. It has been found that the silver coating 18 allows conductive heating of the air space 16a surrounding the bulb end of the thermometer 14 to occur and will allow controlled heating of the epoxy resin 17, while at the same time preventing radiant heat from affecting the thermometer 14.

The backing member 15, on the side against which the thermometer rests, has indicia thereon equivalent to soft, medium and hard cooked levels for boiled eggs and each cooking level is further graduated according to egg size. Thus, a small, medium, large of extra large egg can be cooked to a soft condition by removing the egg when the liquid of the thermometer of the indicator device 10 reaches a level corresponding to that cooking level and to the size of the egg.

Similarly, it can be determined when eggs of other sizes reach medium or hard levels of cooking.

For best results, the indicator 10 should preferably be subjected to the same conditions as the egg to be cooked for some period prior to the actual cooking. For example, if the egg or eggs are kept in a refrigerator prior to cooking the indicator should preferably also be placed in the refrigerator to allow the thermometer temperature to be the same as the inside temperature of the egg. This will ensure a more uniform temperature rise between the inside of the egg and the thermometer inside the housing 13.

WHAT I CLAIM IS: 1. An egg cooking indicator, which comprises a transparent tubular housing closed at both ends, an elongate thermometer located within the housing and having a temperature-responsive part adjacent an end of the housing, a thermal insulating material surrounding such part of the thermometer and serving to reduce its rate of response to temperature change and an air space within the housing substantially surrounding the insulated part of the thermometer.

2. An egg cooking indicator according to claim 1, wherein the thermometer is affixed to a backing member.

3. An egg cooking indicator according to claim 2, wherein the thermometer is located in the housing by the edges of the backing member contacting the wall of the housing and by tabs bent from the backing member which engage the sides of the thermometer and to extend into engagement with the wall of the housing.

4. An egg cooking indicator according to claim 2 or 3. wherein the thermometer is fixed to the backing member by means of the insulating material.

5. An egg cooking indicator according to any preceding claim, wherein the inside of the housing surrounding the temperatureresponsive part of the thermometer is coated with silver.

6. An egg cooking indicator according to claim 1, substantially as described with reference to the accompanying drawing.

7. A method of producing an egg cooking indicator, - which comprises attaching a thermometer to a backing member, providing thermal insulation around a temperature-responsive part of the thermometer and affixing the thermometer to the backing member in a calibrated position, locating the backing member and the thermometer in a transparent tubular housing so that an air space substantially surrounds the insulated temperature-responsive part of the thermometer, silvering the inside of the housing around the temperature-responsive part of the thermometer and closing the housing.

8. A method according to claim 7, substantially as described with reference to the accompanying drawing.

9. An egg cooking indicator when made by a method according to claim 7 or 8.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. then poured into the sleeve 16 whilst the thermometer 14 is held firmly against the tab 15e. The epoxy resin 17 is formed so as to have a dependent nipple 17a, so that if any bottom portion of the suspended backing should contact the housing 13 it will make only point contact with the insulating material 17 and no significant heat transfer will occur thereby. The indicator is made, however, so that the air space 16a is provided between the insulated temperature-responsive end of the thermometer 14 and the wall of the housing 13. The indicia on the backing member 15 form a temperature-responsive gauge applicable to the cooking of eggs, as shown in Figure 2. As such, no conversion is required by the user from scales normally found on thermometers, i.e. Farenheit, centigrade, inches, mm, cm and so on. Because the epoxy resin insulating material 17 is at one end of the thermometer 14 and consequently is positioned below the centre of the housing 13, the centre of gravity of the indicator device 10 is therefore below the centre of the housing 13. Therefore because the housing 13 has a rounded bottom, the device 10 will always be self-righting in use. so that the indicia scale can be readily observed. In addition to providing a scale and acting as a suspension member, the rigid backing member 15 also strengthens the thermometer stem so as to reduce the possibility of breakage if the unit is shaken, bumped or dropped. The lower portion of the inside of the housing 13 is provided with a coating 18 of metallic silver. It has been found that the silver coating 18 allows conductive heating of the air space 16a surrounding the bulb end of the thermometer 14 to occur and will allow controlled heating of the epoxy resin 17, while at the same time preventing radiant heat from affecting the thermometer 14. The backing member 15, on the side against which the thermometer rests, has indicia thereon equivalent to soft, medium and hard cooked levels for boiled eggs and each cooking level is further graduated according to egg size. Thus, a small, medium, large of extra large egg can be cooked to a soft condition by removing the egg when the liquid of the thermometer of the indicator device 10 reaches a level corresponding to that cooking level and to the size of the egg. Similarly, it can be determined when eggs of other sizes reach medium or hard levels of cooking. For best results, the indicator 10 should preferably be subjected to the same conditions as the egg to be cooked for some period prior to the actual cooking. For example, if the egg or eggs are kept in a refrigerator prior to cooking the indicator should preferably also be placed in the refrigerator to allow the thermometer temperature to be the same as the inside temperature of the egg. This will ensure a more uniform temperature rise between the inside of the egg and the thermometer inside the housing 13. WHAT I CLAIM IS:

1. An egg cooking indicator, which comprises a transparent tubular housing closed at both ends, an elongate thermometer located within the housing and having a temperature-responsive part adjacent an end of the housing, a thermal insulating material surrounding such part of the thermometer and serving to reduce its rate of response to temperature change and an air space within the housing substantially surrounding the insulated part of the thermometer.

2. An egg cooking indicator according to claim 1, wherein the thermometer is affixed to a backing member.

3. An egg cooking indicator according to claim 2, wherein the thermometer is located in the housing by the edges of the backing member contacting the wall of the housing and by tabs bent from the backing member which engage the sides of the thermometer and to extend into engagement with the wall of the housing.

4. An egg cooking indicator according to claim 2 or 3. wherein the thermometer is fixed to the backing member by means of the insulating material.

5. An egg cooking indicator according to any preceding claim, wherein the inside of the housing surrounding the temperatureresponsive part of the thermometer is coated with silver.

6. An egg cooking indicator according to claim 1, substantially as described with reference to the accompanying drawing.

7. A method of producing an egg cooking indicator, - which comprises attaching a thermometer to a backing member, providing thermal insulation around a temperature-responsive part of the thermometer and affixing the thermometer to the backing member in a calibrated position, locating the backing member and the thermometer in a transparent tubular housing so that an air space substantially surrounds the insulated temperature-responsive part of the thermometer, silvering the inside of the housing around the temperature-responsive part of the thermometer and closing the housing.

8. A method according to claim 7, substantially as described with reference to the accompanying drawing.

9. An egg cooking indicator when made by a method according to claim 7 or 8.