Abstract:
A thermometer having a temperature sensing element connected to a processor and a display. The processor can receive signals from the temperature sensing element related to the temperature of a patient. The processor and temperature sensing element are enclosed within in the thermometer. The temperature sensing element is adjacent a highly conductive cover defining a temperature probe. The temperature probe includes gold or gold alloy on an outer surface thereof. The outer surface contacts the user and the gold covered probe acts as a hypoallergenic heat transfer element between the user and the temperature sensing element. The gold tip can be used with a glass-tube thermometer or an electronic thermometer.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a thermometer for detecting and displaying a user&#39;s body temperature. More particularly, the present invention pertains to a clinical thermometer with a temperature probe having an outer surface of gold or gold alloy.  
         [0003]     2. Discussion of the Related Art  
         [0004]     There are multiple types of thermometers, including hand held electronic thermometers and glass-tube mercury thermometers. The glass-tube mercury thermometers have gradated scales colored or etched into the glass tube and once the mercury rises and settles in the glass tube due to the temperature of the patient, a user can read the temperature from the scale, calibrated for Fahrenheit or Centigrade. Conventional glass-tube thermometers have long response times and can take several minutes to acquire an accurate reading.  
         [0005]     As an improvement, hand held electronic thermometers were introduced. In the basic electronic thermometer design, a temperature sensing element is connected to a combined, battery-powered computing and display element. The temperature sensing element is placed in a temperature sensing region of the thermometer and has a protective cover enclosing the temperature sensing element inside the thermometer. The cover of the temperature sensing element defines a temperature probe for reading the temperature of a patient. In a conventional electronic oral thermometer, the probe is formed of a metal and is placed towards a distal tip of the thermometer. In use, the temperature probe absorbs heat from the user via the temperature sensing element and an electronic circuit determines and displays the temperature of the probe. Most current electronic thermometers have a response time that is well under one minute. The thermometer&#39;s response time is largely dependant on the thermal conductivity of the probe and the type of sensing element. The temperature probe of most electronic thermometers is formed of nickel because of its high thermal conductivity and relatively low cost compared to other highly conductive metals (e.g., platinum).  
         [0006]     Conventional electronic thermometers, though quick and accurate, have a major drawback. Nickel is a highly allergenic metal. Nickel allergies can cause dermatitis and considerable discomfort. In many cases, only brief contact is needed for the sufferer to experience a reaction. Thus, a significant percentage of the population is allergic to the temperature probe of conventional electronic thermometers.  
         [0007]     As an alternative, some thermometers have stainless steel covered probes. Stainless steel is hypoallergenic and poses no threat to those with metal allergies. However, stainless steel has a very low thermal conductivity compared to other metals and its use in thermometers increases the time needed for an accurate measurement.  
         [0008]     Other available options for those with a nickel allergy are also not desirable. For example, most conventional glass-tube thermometers have also adopted the practice of covering the probe tip with nickel and/or stainless steel, which may be used by those with nickel allergies. Additionally, glass-tube thermometers contain mercury, a known poison. If a glass-tube thermometer is broken during use, the user risks harm from the broken glass and the mercury. Further, glass-tube thermometers are slow and the temperature taking process is cumbersome. Both the glass itself and the stainless steel probe cover have low thermal conductivity.  
         [0009]     Another option for users with nickel allergies is to use a plastic guard placed over the temperature probe. However, plastic guards make the temperature taking process more difficult, as the thermometer may slip out of the guard and fall out of the user&#39;s mouth. In addition, the guards may be displaced or their supply exhausted requiring the user to purchase more guards.  
         [0010]     Thus, there is a need in the art for a low cost, hypoallergenic, thermometer with a highly conductive probe.  
       SUMMARY OF INVENTION  
       [0011]     A hand held electronic thermometer for use with a living being in accordance with the present invention is illustrated. The thermometer is formed of a plastic case having a probe section and a body section. A display is disposed on the body section to display temperatures. The temperature sensing element is mounted in the end of the probe section and covered with a thermally conductive cap which defines a temperature probe of the thermometer. The body section may also include a power/activation button.  
         [0012]     The temperature probe of the claimed thermometer includes gold. Specifically, an outer surface of the temperature probe can be formed of pure gold or a high purity gold alloy. The purity of the gold can be such that it may be considered hypoallergenic. In use, the thermometer poses no threat to those with metal allergies because of the hypoallergenic outer probe surface. Further, the gold outer surface can extend to a proximal section adjacent to the plastic case to ensure the patient only contacts the plastic or the gold probe.  
         [0013]     One embodiment of the temperature probe includes the outer gold surface surrounding an inner support of a different material than that of the gold outer surface. The inner support serves multiple purposes. The inner support may be harder than gold, providing structural support for the temperature probe. In use, the probe may be placed in the user&#39;s mouth and should be adequately constructed to sustain any biting by the user. The inner support should be formed to withstand all appropriate forces that may be incurred by a thermometer. Further, the inner support, like the gold outer surface, may have a high thermal conductivity allowing fast readings to be made by the thermometer. Also, the material of the inner support may be substantially cheaper than gold and using a gold outer surface around the inner support may reduce the cost of the temperature probe.  
         [0014]     Alternatively, the entire temperature probe may be formed of gold or a gold alloy. In this embodiment the gold should be of a composition such that it is hypoallergenic, but also has adequate structural properties for use in the temperature probe of the thermometer.  
         [0015]     The types of gold used for the temperature probe can be pure gold, or a gold alloy. Pure gold is very soft and must be thick to have enough hardness to sustain a theoretical maximum biting force of the patient. A thick temperature probe can be used but can increase the size of the temperature probe and cost more to manufacture.  
         [0016]     Gold is mixed with other metals to make gold alloy which has a higher hardness relative to pure gold. The most common metals to alloy with gold are copper and silver, but nickel, palladium, zinc, and other metals are used.  
         [0017]     In the present invention, an embodiment uses copper, silver or zinc as the alloy metal with gold and not nickel. Typical allergies to gold stem from low karat gold with a nickel alloy. High karat gold, e.g. 18 and 22 karats, contains a high percentage of gold in the alloy to minimize the effects of the additional metal. Further, gold alloy is harder than pure gold.  
         [0018]     As an example, typical 18 karat gold alloy has a hardness which is two to three times harder than (almost) pure gold. The higher the hardness, the better the gold probe withstands biting forces.  
         [0019]     The hypoallergenic gold covered temperature probe is not limited to use in oral thermometers. Those with metal allergies have a reaction when allergenic metals contact any exposed surface of their bodies. Thus, a temperature probe with an outer surface of gold is also advantageous for use in rectal and axillary thermometers. An embodiment of the invention can be used for a gold covered temperature probe of a glass-tube thermometer.  
     
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0020]     The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of a specific embodiment thereof, especially when taken in conjunction with the accompanying drawings wherein like reference numerals in the various figures are utilized to designate like components, and wherein:  
         [0021]      FIG. 1  is a perspective view of an embodiment of the gold tip thermometer of the present invention;  
         [0022]      FIG. 2  is a top view of the embodiment illustrated in  FIG. 1 ;  
         [0023]      FIG. 3  is a right side view of the embodiment illustrated in  FIG. 1 ; and  
         [0024]      FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 2  of the temperature probe tip. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]     Referring to  FIGS. 1, 2  and  3 , an embodiment of a hand held electronic thermometer  100  for use with a living being and in accordance with the present invention is illustrated. The thermometer  100  is formed of a plastic case  108  having a probe section  110  and a body section  112 . A display  106  is disposed on the body section  112  to display temperatures. A battery (not shown), processor  104  and temperature sensing element  102  (as in  FIG. 4 ) are housed within plastic case  108 . The temperature sensing element  102  is mounted in the end of probe section  110  and covered with a thermally conductive cap which defines a temperature probe  116  of thermometer  100 . Body section  112  may also include a power/activation button  117 .  
         [0026]     The temperature probe  116  of the thermometer  100  includes gold. Specifically, an outer surface  120  of temperature probe  116  can be formed of pure gold or a high purity gold alloy. The purity of the gold can be such that it may be considered hypoallergenic. In use, the thermometer poses no threat to those with metal allergies because of its hypoallergenic outer probe surface  120 .  
         [0027]     Temperature probe  116  includes a proximal face  122  adjacent a distal end  128  of plastic case  108 . The gold outer surface  120  extends to proximal face  122  of temperature probe  116 , such that no allergenic metals within thermometer  100 , and specifically within temperature probe  116 , contact the user. Thus, the thermometer provides a safe alternative to conventional electronic thermometers for those allergic to metals, specifically nickel.  
         [0028]     As shown in  FIG. 4 , one embodiment of temperature probe  116  includes an inner support  130  of a different material than that of gold outer surface  120 . Inner support  130  serves multiple purposes. The inner support  130  may be harder than gold, providing structural support for temperature probe  116 . In use, probe  116  may be placed in the user&#39;s mouth and should be adequately constructed to sustain any biting by the user. Inner support  130  should be formed to withstand all appropriate forces that may be experienced by a thermometer. Further, inner support  130 , like gold outer surface  120 , may have a high thermal conductivity allowing fast readings to be made by thermometer  100 . Also, the material of inner support  130  may be substantially cheaper than gold and using a gold outer surface  120  around inner support  130  may achieve the advantages of the present invention but reduce the cost of temperature probe  116 . In a preferred embodiment, nickel is used for inner support  130  because of its advantageous properties, e.g., hardness, and the gold outer surface  120  is plated on the nickel inner support  130 .  
         [0029]     Alternatively, the entire temperature probe  116  may be formed of gold or a gold alloy (not shown). In this embodiment, the gold should be of a composition such that it is hypoallergenic, but also has adequate structural properties for use in temperature probe  116  of thermometer  100 .  
         [0030]     The types of gold used for the temperature probe  116  can be pure gold, or a gold alloy. Pure gold is very soft and must be thick to have enough hardness to sustain a theoretical maximum biting force of the patient. A thick temperature probe  116  can be used but can increase the size of the temperature probe  116  and cost more to manufacture.  
         [0031]     Gold is mixed with other metals to make gold alloy which has a higher hardness than pure gold. Gold alloy is typically identified by a “karat” purity, e.g. 9, 14, 18, and 22 karat. A karat denotes 1/24th, i.e., one part in 24 or 41.66 parts per 1000. Thus, 9 karat gold must be at least 9 parts gold out of 24, which is equivalent to 37.5%, and other metals make up the remaining 62.5%. Similarly, 18 karat gold contains 75% gold ( 18/24) and 24 karat gold is pure gold. The most common metals to alloy with gold are copper and silver, but nickel, palladium, zinc, and other metals are used. Several formulations for gold alloys are set out in Table 1.  
                                                                           TABLE 1                           Percentages by Weight            Alloy   Gold   Silver   Copper   Zinc   Nickel   Palladium                    9 Yellow   37.5   10.0   45.0   7.5   0.0   0.0       9 White   37.8   0.0   40   10.4   11.8   0.0       14 Yellow   58.5   43   1.2   6.3   0.0   0.0       14 White   58.5   0.5   27.0   7.0   7.0   0.0       18 Yellow   75.0   16.0   9.0   0.0   0.0   0.0       18 White   75.0   4.0   4.0   0.0   0.0   17.0       22 Yellow   91.7   5.5   2.8   0.0   0.0   0.0       24   100.0   0.0   0.0   0.0   0.0   0.0                  
 
         [0032]     In the present invention, an embodiment uses copper, silver or zinc as the alloy metal with gold, and not nickel. Typical allergies to gold stem from low karat gold with a nickel alloy. High karat gold, e.g., 18 and 22 karats, contains a high percentage of gold in the alloy to minimize the effects of the additional metal. Further, alloys using copper and silver bind better with higher percentages of gold and typically cause few to no allergic reactions. One embodiment of the invention uses gold with less than 0.05% nickel by mass, meeting the European requirement of being nickel-free.  
         [0033]     Further, alloy gold is harder than pure gold. Table 2 below outlines the Vickers Hardness for various gold alloys identified by the karat of the gold;  
                                     TABLE 2                       Alloy   Hardness as Cast   Maximum Annealed Hardness                                9   70 to 105   160 to 170       14   125 to 165    150 to 180       18   85 to 125   170 to 230       22   70   60 to 90       23.75   40   70                  
 
         [0034]     As shown in Table 2, typical 18 karat gold alloy has a Vickers Hardness, once annealed, which is two to three times harder than (almost) pure gold. The higher the hardness, the better the gold tip withstands biting forces.  
         [0035]     In an embodiment, due to its high gold content, lack of nickel as an alloy metal and high hardness, 18 karat yellow gold can be used for the gold outer surface  120 . 18 karat gold provides a high gold ratio, but not as high as 22 karat so it is less expensive. Further, 18 karat gold has a lower cast hardness than 14 karat gold, thus improving its workability in manufacturing the temperature probe  116 .  
         [0036]     The temperature sensing element  102  is disposed within the thermometer  100  adjacent to a surface of temperature probe  116 . Temperature probe  116  may contain an indent or bore  150  extending in from proximal face  122  and temperature sensing element  102  may be placed within the indent or bore  150 , as shown in  FIG. 4 .  
         [0037]     The hypoallergenic gold covered temperature probe is not limited to use in oral thermometers. Those with metal allergies have a reaction when allergenic metals contact any exposed surface of their bodies. Thus, a temperature probe with an outer surface of gold is also advantageous for use in rectal and axillary thermometers.  
         [0038]     An embodiment of the invention can be used for a gold covered temperature probe of a glass-tube thermometer. A temperature sensing end of a glass-tube thermometer may include a gold cap placed over the glass. The use of a gold cover over the glass helps decrease the thermal resistance between the user and the mercury while retaining the hypoallergenic properties of conventional glass-tube thermometers.  
         [0039]     While there have been shown, described, and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. For example, it is expressly intended that all combinations of those elements and/or steps which perform substantially the same function, in substantially the same way, to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.