JP7477164B2 - thermometer - Google Patents

Description

Article 30, paragraph 2 of the Patent Act is applicable. Published in the flyer for the BC series of food core temperature sensors issued on March 26, 2020.

The present invention relates to a thermometer, and more specifically to a thermometer that detects the internal temperature of an object by inserting a probe into the object.

A thermometer has been proposed that detects the internal temperature of an object by inserting a probe into the object (see, for example, Patent Document 1). The thermometer described in Patent Document 1 has a locking member that is inserted into a through hole formed in the handle, and a locking body that is nested in the handle is fixed to the handle, making it possible to assemble the thermometer with the sensor body protruding from the tip of the handle without using screws. This is advantageous in making the holes and grooves formed in the outer surface of the handle smaller, and has the advantage that dirt does not accumulate on the handle itself, keeping it constantly clean.

JP 2018-205049 A

The thermometer described in Patent Document 1 above has a complex structure for the anti-removal body, so in order to simplify the manufacturing process, it was necessary to make the anti-removal body out of resin. However, if the anti-removal body is made of resin, it is not possible to improve durability such as chemical resistance and heat resistance. On the other hand, if the anti-removal body is made of metal in order to improve its chemical resistance, it is not possible to improve productivity.

The object of the present invention is to provide a thermometer that has a structure that allows it to be kept clean, and that achieves both improved productivity and improved durability.

The thermometer of the present invention, which achieves the above object, is equipped with a probe that can be inserted into and removed from a measurement object, a cylindrical handle, and a temperature detection element with a temperature measuring part disposed at the tip of the probe, and the probe protrudes from the tip of the handle and the signal line of the temperature detection element is led out from the end of the handle. The handle is made of a metal with a tip cap, a cylinder, and an end cap arranged in order from the tip to the end, the tip cap is fixed to the middle of the probe and a screw thread is formed on the outer cylindrical surface of the end, both ends of the cylinder are open and a screw thread is formed on the inner cylindrical surface of the tip and the inner cylindrical surface of the end, the end cap is fixed to the middle of the signal line and a screw thread is formed on the outer cylindrical surface of the tip, the tip cap is screwed to the tip of the cylinder to seal the tip opening of the cylinder, and the end cap is screwed to the end of the cylinder to seal the end opening of the cylinder.

According to the present invention, the handle, which has a structure that allows it to be kept clean, is made of metal, which is more durable than resin, and can be assembled in a simple manner by screwing the lid onto both ends of the cylinder, simplifying the structure of each component and reducing the number of parts. Therefore, even if the thermometer has a structure that allows it to be kept clean, it is possible to achieve both improved productivity and improved durability.

FIG. 1 is a perspective view illustrating an embodiment of a thermometer. 2 is a combination of a cross-sectional view illustrating a cross section of the probe and the temperature detection element in FIG. 1 and a side view illustrating a side surface of a tip cap of a handle. FIG. 2 is a side view illustrating an example of a side surface of an end cap of the handle and a signal line of a temperature detection element in FIG. 1 . 2 is a side view illustrating a side surface of the cylindrical body of the handle of FIG. 1 . FIG.

The following describes an embodiment of the thermometer with reference to the drawings. In the drawings, the X direction is the direction from the tip to the end of the thermometer 1, the extension direction of the probe 10 and the cylinder axis direction of the handle 20, the YZ plane is a plane perpendicular to the X direction, and the Y and Z directions are mutually perpendicular directions. In addition, the tip in this disclosure refers to the side of the thermometer 1 from which the probe 10 protrudes, and the end refers to the side of the thermometer 1 from which the signal line 34 of the temperature detection element 30 is led out. In addition, in this disclosure, the outside refers to the outside of the cylinder axis of the handle 20, and the inside refers to the inside of the cylinder axis of the handle 20. Note that the dimensions of the drawings have been changed to make the configuration easier to understand, and the ratios of the plate thickness, width, length, etc. of each member and each part do not necessarily match the ratios of the actual manufactured items.

As shown in FIG. 1, the thermometer 1 of the embodiment includes a probe 10, a handle 20, and a temperature detection element 30, with the probe 10 protruding from the tip of the handle 20 and the signal line 34 of the temperature detection element 30 leading out from the end of the handle 20. The thermometer 1 is a device in which the protruding probe 10 is inserted into an object to be measured, the temperature inside the object is detected by the temperature detection element 30, and a measuring device (not shown) to which the signal line 34 is connected displays the temperature detected by the temperature detection element 30.

The temperature detection element 30 has a temperature measuring part 33, which is a junction where the tips of two types of metal wires 31, 32 are in contact with each other, and a signal wire 34 formed by covering the metal wires 31, 32 together with a coating material, and transmits the thermoelectromotive force generated in the temperature measuring part 33 to the measurement device via the signal wire 34. Examples of the temperature detection element 30 include thermocouples of various types, such as type K, which uses chromel for the positive electrode and alumel for the negative electrode, type E, which uses chromel for the positive electrode and constantan for the negative electrode, and type B, which uses a platinum-rhodium alloy (rhodium content 30%) for the positive electrode and a platinum-rhodium alloy (rhodium content 6%) for the negative electrode, but it may also be composed of a resistance temperature detector that utilizes the property that the electrical resistance value changes according to the temperature change of metals such as platinum.

The probe 10 is made of a metal tube that is closed with a needle-like pointed tip, and has a needle-like tip 11 and a cylindrical tube 12 that is open at the end. An example of the metal tube is a stainless steel circular tube. The temperature measuring part 33 of the temperature detection element 30 is disposed at the tip 11 of the probe 10, and the metal wires 31, 32 of the temperature detection element 30 are inserted inside the tube 12 while being covered with a coating material, and these metal wires 31, 32 are led out from the end of the tube 12. The tip of the metal tube of the probe 10 is closed by welding, and the closed tip is polished to form the needle-like tip 11.

Although the tip 11 may be constructed separately from the temperature measuring part 33 of the temperature detection element 30, it is preferable that the tip 11 is constructed integrally with the temperature measuring part 33. Specifically, the tip 11 is formed by simultaneously welding the metal wires 31 and 32 of the temperature detection element 30 when the tip of the metal tube constituting the probe 10 is closed by welding. In this way, the tip 11 and the temperature measuring part 33 of the temperature detection element 30 are constructed integrally, so that the process of forming the tip 11, the process of forming the temperature measuring part 33 of the temperature detection element 30, and the process of fixing the temperature measuring part 33 to the tip 11 can be performed in a single process, which is advantageous for improving productivity. It is also advantageous for avoiding a situation in which the tip 11 and the temperature measuring part 33 peel off from each other, making it impossible to accurately detect the temperature of the measurement object.

The handle 20 is made of metal, with the tip cap 40, the cylindrical body 50, and the end cap 60 arranged in this order from the tip to the end, and the tip cap 40 and the end cap 60 are screwed to both ends of the cylindrical body 50 to form a sealed structure. In this disclosure, "sealed" refers to a state in which the second characteristic number of the IP code defined in "IEC 60529: Degression of protection provided by enclosures (IP Code)," a standard of the International Electrotechnical Commission (IEC), is "5" or more. The first characteristic number of the IP code is not particularly limited. An example of the metal that constitutes the handle 20 is stainless steel.

As shown in FIG. 2, the tip cap 40 is sealed and fixed midway through the probe 10, which is located in the center when viewed in the X direction, forming a mushroom shape. The tip cap 40 has a tip head 41, a tip shaft 42, a probe hole 43, and a tip closure 44, with the tip head 41, tip closure 44, and tip shaft 42 arranged from the tip to the end, and the probe hole 43 penetrating them.

The tip head 41 has a truncated cone shape or a cone shape whose outer diameter decreases toward the tip, and the maximum outer periphery on the terminal side projects outward beyond the tip shaft 42. The outer periphery diameter of the maximum outer periphery of the tip head 41 is equal to the outer periphery diameter of the tip of the cylindrical body 50, and when the tip cap 40 is screwed onto the tip of the cylindrical body 50, the terminal end of the tip head 41 and the tip end of the cylindrical body 50 form a continuous outer cylindrical surface except for the boundary portion.
The distal shaft portion 42 has a cylindrical shape and has a screw thread formed on an outer cylindrical surface of at least the distal end portion. The screw thread of the distal shaft portion 42 may be formed over the entire distal shaft portion 42.

The probe 10 is inserted into the probe hole 43. The tip of the probe hole 43 protrudes from the tip of the tip head 41, and its end protrudes from the end of the tip shaft 42. The tip and end of the probe hole 43 do not have to protrude. The end of the probe hole 43 is welded around the entire inner circumference to the entire outer circumference of the probe 10 and sealed. The part where the entire circumference is welded is called the tip weld 45. The tip weld 45 makes it possible to seal the space between the probe 10 and the probe hole 43. In addition, by forming the tip weld 45 at the end of the probe hole 43, the tip weld 45 is covered by the handle 20 without being exposed to the outside of the handle 20, which is advantageous in improving the durability of the welded area.

The tip closure 44 is located between the tip head 41 and the tip shaft 42, and consists of a tip annular surface 46 and a tip outer cylindrical surface 47 that are perpendicular to each other. The tip annular surface 46 is a ring-shaped surface that abuts against the tip of the cylindrical body 50 when the tip cap 40 is screwed onto the cylindrical body 50, and closes the tip opening of the cylindrical body 50 except for the probe hole 43. The outer diameter of the tip annular surface 46 is equal to the outer diameter of the tip of the cylindrical body 50. The tip outer cylindrical surface 47 protrudes from the tip annular surface 46 toward the distal end and abuts against the entire tip inner cylindrical surface 55 of the cylindrical body 50 when the tip cap 40 is screwed onto the cylindrical body 50. The outer diameter of the tip outer cylindrical surface 47 is equal to the outer diameter of the thread formed on the tip shaft 42. If the tip cap 40 and the cylindrical body 50 can be screwed together to maintain a sealed state, the tip closure 44 may not be necessary. In this embodiment, the provision of the tip closure 44 makes it possible to seal the tip side of the screwed portion except for the probe hole 43, which is advantageous for maintaining a sealed state.

As shown in FIG. 3, the end cap 60 is fixed to the middle of the signal line 34, which is located in the center when viewed in the X direction, forming a mushroom shape. The end cap 60 has an end head 61, an end shaft 62, a signal line hole 63, and an end blocking portion 64, and the end head 61, end blocking portion 64, and end shaft 62 are arranged from the end to the tip, and the signal line hole 63 passes through them.

The terminal head 61 has a cylindrical shape, and its outer periphery protrudes outward beyond the terminal shaft portion 62. The outer diameter of the outer periphery of the terminal head 61 is equal to the outer diameter of the terminal end of the cylindrical body 50, and when the terminal cap 60 is screwed onto the terminal end of the cylindrical body 50, the outer periphery of the terminal head 61 and the tip end of the cylindrical body 50 form a continuous outer cylindrical surface except for the boundary portion. It is preferable that the terminal end of the terminal head 61 is tapered, and similar to the terminal head 41, it may be a truncated cone shape or a cone shape with the outer diameter decreasing toward the terminal.
The distal shaft portion 62 has a cylindrical shape and is threaded on at least the outer cylindrical surface of the tip portion. The threads of the distal shaft portion 62 may be formed over the entire length of the distal shaft portion 62.

The signal line hole 63 has the signal line 34 inserted therein. The tip of the signal line hole 63 is located at the tip of the terminal shaft 62, and its end is located at the end of the terminal head 61. The tip and end of the signal line hole 63 may protrude. The end of the signal line hole 63 is sealed and fixed by bonding the entire inner circumference of the end of the coating material 35 that covers the signal line 34. This bonded portion is called the terminal bonding portion 65. The terminal bonding portion 65 makes it possible to seal the gap between the signal line 34 and the signal line hole 63. In addition, by forming the terminal bonding portion 65 at the tip of the signal line hole 63, the terminal bonding portion 65 is covered by the handle 20 without being exposed to the outside of the handle 20, which is advantageous for improving the durability of the bonded portion. It is desirable for the end of the signal line hole 63 to have a tapered shape in order to improve the durability of the signal line 34.

The coating material 35 is a member that maintains the sealing between the outer circumference of the signal line 34 and the inner circumference of the signal line hole 63, and specifically, maintains the outer diameter of the signal line 34 unchanged when coated with the coating material 35. The coating material 35 is preferably harder than the coating material that constitutes the signal line 34, while being in close contact with the signal line 34 and shrinking the signal line 34. By sealing and fixing the signal line hole 63 and the signal line 34 via the coating material 35, it is advantageous to prevent peeling of the adhesive portion. In addition, it is preferable to form a knot 36 on the signal line 34 on the tip side of the coating material 35. By forming the knot 36, it is possible to prevent the signal line 34 from slipping out of the signal line hole 63.

The end plug 64 is located between the end head 61 and the end shaft 62, and consists of an end annular surface 66 and an end outer cylindrical surface 67 that are perpendicular to each other. The end annular surface 66 is an annular surface that abuts against the end of the cylinder 50 when the end cap 60 is screwed onto the cylinder 50, and closes the end opening of the cylinder 50 except for the signal line hole 63. The outer diameter of the end annular surface 66 is equal to the outer diameter of the end of the cylinder 50. The end outer cylindrical surface 67 is a surface that protrudes from the end annular surface 66 toward the tip side and abuts against the entire end inner cylindrical surface of the cylinder 50 when the end cap 60 is screwed onto the cylinder 50. The outer diameter of the end outer cylindrical surface 67 is equal to the outer diameter of the thread formed on the end shaft 62. If the end cap 60 and the cylinder 50 can be screwed together to maintain a sealed state, the end plug 64 may not be necessary. In this embodiment, the provision of the end blocking portion 64 makes it possible to seal the area distal to the screwed portion except for the signal line hole portion 63, which is advantageous for maintaining a sealed state.

As shown in FIG. 4, the cylinder 50 has a cylindrical shape with its axis oriented in the X direction and both ends open. The cylinder 50 has a tip opening 51, a terminal opening 52, and a central portion 53 disposed therebetween, and the cross section of each portion in the YZ plane forms a circular ring shape.

The tip opening 51 has a cylindrical shape, and its outer diameter is longer than the outer diameter of the central portion 53. The tip opening 51 has a tip female thread portion 54 and a tip inner cylindrical surface 55. The tip female thread portion 54 is a thread formed on the inner cylindrical surface of the tip opening 51. The tip inner cylindrical surface 55 is located on the tip side of the tip female thread portion 54, and is an inner cylindrical surface that is expanded in diameter at least to the root of the thread formed on the tip female thread portion 54.

Distal opening 52 has a cylindrical shape and an outer diameter thereof is greater than the outer diameter of central portion 53. Distal opening 52 has a terminal female thread 56 and a terminal inner cylindrical surface 57. Terminal female thread 56 is a thread formed on the inner cylindrical surface of terminal opening 52. Distal inner cylindrical surface 57 is disposed distally of terminal female thread 56 and is an inner cylindrical surface that expands in diameter to at least the root of the thread formed on terminal female thread 56.
The inner diameter of the central portion 53 is equal to the inner diameter of the thread formed on the tip female thread portion 54 .

The manufacturing method of the thermometer 1 will now be described. The tip of the elongated metal tube is welded together with the metal wires 31 and 32 of the temperature detection element 30 to seal it, and the sealed tip portion is then polished. This process forms both the tip portion 11 of the probe 10 and the temperature measuring portion 33 of the temperature detection element 30, and also fixes the temperature measuring portion 33 to the tip portion 11. This completes the manufacturing process of the probe 10.

Then, the outer surface of the cylindrical metal block is cut to form a mushroom shape with a cap and a handle, and the outer cylindrical surface of the handle is threaded. The cap of this mushroom shape becomes the tip head 41, the handle becomes the tip shaft 42, and the boundary between the cap and the handle becomes the tip closure 44. Next, a through hole is formed that penetrates from the tip of the cap to the end of the handle. This through hole becomes the probe hole 43. This completes the manufacturing process for the tip cap 40. Note that the manufacturing process for the end cap 60 is the same as that for the tip cap 40, so a description thereof will be omitted.

Next, the outer surface of the thick metal tube in the center of the tube axis direction is cut, and the inner cylindrical surfaces of both ends of the metal tube are threaded. This completes the manufacturing process for the tube 50.

Next, the probe 10 is inserted into the probe hole 43 of the tip cap 40, and the end of the probe hole 43 and the probe 10 are sealed and fixed by welding. Next, the signal line 34 of the temperature detection element 30 is inserted into the inside of the cylindrical body 50 and into the signal line hole 63 of the end cap 60, and the signal line hole 63 and the part of the signal line 34 covered with the coating material 35 are sealed and fixed by adhesive. Next, the tip cap 40 is screwed onto the tip of the cylindrical body 50, and the end cap 60 is screwed onto the end of the cylindrical body 50. Next, the boundary between the tip cap 40 and the cylindrical body 50 and the boundary between the end cap 60 and the cylindrical body 50 are fixed by spot welding. The spot welded parts are called the tip spot weld 48 and the end spot weld 68. This completes the assembly process for the thermometer 1.

On the outer surface of the handle 20 of the thermometer 1 of this embodiment, there is only a gap between the probe 10 and the probe hole 43, a gap at the boundary between the tip cap 40 and the cylindrical body 50, a gap at the boundary between the end cap 60 and the cylindrical body 50, and a gap between the signal line 34 and the signal line hole 63. Therefore, dirt is less likely to accumulate on the outer surface of the handle 20.

The gap between the probe 10 and the probe hole 43 is sealed by the tip weld 45, and the gap at the boundary between the tip cap 40 and the cylinder 50 is sealed by the tight fit of the tip blocking part 44 and the cylinder 50 and the fitting of the tip cap 40 and the cylinder 50 by the screw action. Similarly, the gap at the boundary between the end cap 60 and the cylinder 50 is sealed by the tight fit of the end blocking part 64 and the cylinder 50 and the fitting of the end cap 60 and the cylinder 50 by the screw action, and the gap between the signal line 34 and the signal line hole 63 is sealed by the end adhesive part 65. This sealed structure makes it possible to clean the handle 20 and the probe 10 even if they become dirty.

As described above, the thermometer 1 of this embodiment can be kept clean. In addition to being able to keep the thermometer 1 clean at all times, it is assembled without using fasteners such as screws or bolts, and there is no risk of these fasteners falling off during use. Therefore, it is suitable for measuring the internal temperature of food, etc.

Furthermore, according to the thermometer 1 of this embodiment, the handle 20, which has a structure that allows it to be kept clean, can be made of metal, which is more durable than resin, thereby improving durability. Also, the handle 20 can be assembled by the simple method of screwing the lid onto both ends of the tube, simplifying the structure of each component and reducing the number of parts. Therefore, even though the thermometer 1 has a structure that allows it to be kept clean, it is possible to achieve both improved productivity and improved durability.

Reference Signs List 1: Thermometer 10: Probe 20: Handle 30: Temperature detection element 34: Signal line 40: Tip cap 50: Cylindrical body 60: End cap

Claims (4)

A thermometer comprising a probe that can be inserted into and removed from a measurement object, a cylindrical handle, and a temperature detection element having a temperature measuring portion disposed at the tip of the probe, the probe protruding from the tip of the handle, and a signal line of the temperature detection element being led out from the end of the handle,
the handle comprises a tip cap, a cylinder, and an end cap arranged in this order from the tip to the end, and are made of metal; the tip cap is hermetically fixed to a position midway on the probe and a screw thread is formed on the outer cylindrical surface of the end portion; the cylinder is open at both the tip and end and a screw thread is formed on each of the inner cylindrical surfaces of the tip and end portion; the end cap is hermetically fixed to a position midway on the signal line and a screw thread is formed on the outer cylindrical surface of the tip portion; the tip cap is screwed onto the tip of the cylinder to seal the tip opening of the cylinder, and the end cap is screwed onto the end portion of the cylinder to seal the end opening of the cylinder, forming a sealed structure. the tip cap comprises a tip shaft portion having an outer cylindrical surface on which a screw thread is formed, a tip head portion which projects outward on the tip side from the tip shaft portion, and a probe hole portion through which the probe is inserted by penetrating the tip shaft portion and the tip head portion, the end of the probe hole portion being fixed to the probe in a hermetically sealed manner,
2. The thermometer according to claim 1, wherein the end cap comprises a terminal shaft portion having an outer cylindrical surface on which a screw thread is formed, a terminal head portion protruding outward on the terminal side from the terminal shaft portion, and a signal line hole portion through which the signal line is inserted, passing through the terminal shaft portion and the terminal head portion, and a tip of the signal line hole portion is hermetically fixed to the signal line. The cylindrical body has a tip inner cylindrical surface that expands to the root of the thread at a portion distal to the thread formed at the tip portion, and a terminal inner cylindrical surface that expands to the root of the thread at a portion distal to the thread formed at the end portion,
said tip cap has a tip closing portion formed with a tip annular surface which closes the tip opening of said cylindrical body except for the probe hole portion when said tip cap is screwed onto said cylindrical body, and a tip outer cylindrical surface which projects from said tip annular surface to the distal end side and abuts against the entire tip inner cylindrical surface,
3. The thermometer according to claim 2, wherein the end cap has an end blocking portion formed with an end annular surface that closes the end opening of the cylinder except for the portion of the signal line hole when the end cap is screwed onto the cylinder, and an end outer cylindrical surface that extends from the end annular surface toward the tip and abuts against the entire area of the end inner cylindrical surface. The thermometer according to any one of claims 1 to 3, wherein the tip cap and the end cap are welded while being screwed to the cylindrical body.

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