JP2005144591A - Heat knife - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat knife for properly controlling the heating temperature, even if a battery is used without using an external power source, in a small type suitable for processing an object having small heat capacity. <P>SOLUTION: This heat knife 1 is composed of a blade 3 internally provided with a film heater 2, and a grip part 4 for holding this blade 3. The film heater 2 is properly selected in a range of resistance of 1 Ω to 10 Ω, and the thickness of 0.3 mm to 1.0 mm in response to the maximum ultimate temperature of an edge 3a. The grip part 4 is formed by threadably attaching a connector part 8 to a rear part by arranging a switch 7 on a surface of a cylindrical body 6 for storing a dry battery 5. An electric circuit in the grip part 4 is set so that an electric current flows to the heater only for a predetermined time, after pushing the switch 7 by interposing a timer circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat knife that includes a cutting edge that is connected to a heat generating portion to be in a heated state, and easily cuts and shapes low-temperature solidified products such as foamed polystyrene, resin products, ice, and butter.

  Conventionally, a wire-type saw is generally used when cutting expanded polystyrene and the like, and a knife with a heater called a heat knife has been used to shape details.

  A butter knife is a knife used to apply butter that is solid to bread, etc. However, butter that has been consolidated at a low temperature does not easily become liquid even if the bread is baked. In such a case, the butter can be applied smoothly by warming the knife edge. When cutting a cake with a cake knife or the like, fresh cream or sponge is brought into close contact with the cutting edge of the cake knife, resulting in a crushed shape. Therefore, in order to cut the cake well, by sticking the cutting edge of the cake knife, the close contact with the fresh cream can be avoided and the cake can be cut well.

Accordingly, there has been a demand for a so-called heat knife having a heated cutting edge even in a butter knife or a cake knife. Such a heat knife is provided with a mechanism for heating the knife part at the tip, and examples of conventional techniques are described in the following documents.
JP 2002-166395 A Japanese Patent Laid-Open No. 10-201597

  Here, the heat knife described in Patent Document 1 is a cutting jig mainly used for cutting a rubber insulating connecting material that is a connecting member of a power cable, and a mechanism for generating heat (for example, Ni-Cr). An electric wire is passed through the alloy wire to create a heating element), a mechanism for transmitting the generated heat to the blade (metal member such as iron), and a temperature sensor for controlling the heat in the grip They were installed inside and connected to a temperature control mechanism with a cord, and these were connected to an external power source. In this conventional heat knife, the switch in the temperature control mechanism is turned on, and the temperature setting dial is set to 80 ° C., for example. Moreover, the heat knife described in Patent Document 2 is a butter knife provided with so-called heating means, and has a configuration including a heater means in a spatula portion and a switch and a battery in a handle portion.

  However, the conventional heat knife described in Patent Document 1 is inconvenient to handle because it uses an external power source, and the entire apparatus is large in size. Therefore, it is suitable particularly when processing a small heat capacity. There wasn't. On the other hand, in the case of the butter knife described in Patent Document 2, the blade edge temperature is generally considered to be an appropriate temperature of 50 ° C. to 80 ° C. However, in this document, the heater means housed in the spatula portion and the battery installed in the handle portion are used. Since there is no specific description of the configuration or the like, it is unclear what kind of member is actually used for heating and controlling to a predetermined temperature.

  The present invention has been made to solve the above-mentioned problems of conventional heat knives, and its purpose is to provide a small heat knife suitable for processing a small heat capacity. Yes. It is another object of the present invention to provide a heat knife capable of appropriately controlling the heating temperature even if a battery is used without using an external power source.

  In order to solve the above problems, a heat knife according to the present invention includes a blade connected to the heat generating portion and a gripping portion that holds the blade, and the blade includes a film heater that forms a part of the heat generating portion. The grip portion includes an electric circuit for supplying electricity to the film heater.

  The shape of the blade has a sharp edge in the cutting direction, and it is desirable to use a metal having good toughness and heat conductivity, such as stainless steel or titanium alloy, or iron or iron alloy, nickel or nickel alloy, etc. . In addition, the material and shape are set so that the blade tip will not bend due to the temperature rise by the heater.

  As a means for installing the film heater in the blade, for example, a film heater is inserted into a single plate material, the film heater is inserted, and then the cut is completely sealed using plastic or acrylic resin to package the insertion port. Alternatively, there is a method in which the periphery is welded after being sandwiched between two metal plates, or a recess is provided in the plate material and the film heater is accommodated, and then a lid is covered with another plate material. By sealing the film heater in this way, it is possible to cope with water washing.

  The film heater is a thin-film planar heater in which a heating resistor made of a nickel alloy or the like is sandwiched between insulating materials made of a polyimide sheet or the like, and can be processed into an arbitrary shape. The lead wire is connected to the electric circuit of the grip part to generate power and receive heat.

  The blade of the heat knife according to claim 2 sandwiches a film heater having a thickness of 0.3 mm to 1.0 mm and a resistance of 1 Ω to 10 Ω in a metal plate, and the electric circuit includes a heating part. It is characterized by interposing a dry battery, a switch, and a timer circuit constituting a part.

  The grip is a cylindrical body that houses a dry battery, and a switch is provided on the surface. The positive electrode of the dry battery is electrically connected to the heater via a lead wire, and the other electrode of the heater is connected to a switch. The cathode of the dry battery is connected to a connector portion screwed into the grip portion, and further connected to a switch via a timer circuit.

  After pressing the switch due to the presence of the timer circuit, a current is allowed to flow through the heater for a predetermined time, for example, about 10 seconds. For example, a dry battery having a power source of 1.5V to 9V is used.

  The heat generating portion of the heat knife according to claim 3 is characterized in that a film heater and a dry battery having a heat output such that the blade temperature is 50 ° C. to 100 ° C. are selected. Select the heater resistance and voltage according to the size of the blade and the target temperature, and adjust the maximum temperature.

  Since the heat knife of this invention has a film heater in the blade, it is possible to provide a small heat knife suitable for processing one having a small heat capacity. Since the heat knife according to claim 2 is provided with a dry battery, a switch, and a timer circuit in the grip portion, the blade edge can be heated for a predetermined time after the switch is pressed. For this reason, even if it uses a battery, without using an external power supply, appropriate heating temperature management is attained.

  The heat knife according to claim 3 selects a film heater and dry battery having a heat output such that the blade temperature is 50 ° C. to 100 ° C. Therefore, safety is ensured and it can be used as a butter knife or cake knife.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a heat knife. The heat knife 1 includes a blade 3 in which a film heater 2 is provided, and a grip portion 4 that holds the blade 3. The shape of the blade 3 has a sharp blade edge 3a in the cutting direction. For example, a 0.5 mm cut is made in a stainless steel plate having a length of 105 mm, a width of 15 mm, and a thickness of 1.5 mm, and a film heater is formed in this gap. 2 is inserted. As the film heater 2, for example, a 5.2 Ω sheet-like resistor having a thickness of 0.3 mm and coated with polyimide is inserted. The film heater 2 is appropriately selected within the range of resistance of 1Ω to 10Ω and thickness of 0.3 mm to 1.0 mm in accordance with the maximum temperature reached by the cutting edge 3a. Create a matching cut.

  The film heater 2 connects the lead wires 2a and 2b to an electric circuit provided in the grip portion 4, and generates heat when supplied with electric power. The grip portion 4 is provided with a switch 7 on the surface of a cylindrical body 6 that houses the dry battery 5, and a connector portion 8 is screwed to the rear portion. The switch 7 is water-resistant so as not to cause a problem even if it is splashed with water, and an O-ring (not shown) is installed in the connector portion 8 so that water or the like cannot enter. The positive electrode of the dry battery 5 is electrically connected to the film heater 2 via the lead wire 2 a, and the other lead wire 2 b of the heater 2 is connected to the switch 7.

  This electric circuit is set so that a current flows through the heater for a predetermined time, for example, about 10 seconds after the switch 7 is pressed via a timer circuit. Here, details of the electric circuit will be described with reference to FIGS. 2 is a heat knife circuit block diagram, FIG. 3 is a heat knife circuit diagram, and FIG. 4 is a circuit timing diagram.

  The electric circuit includes a dry battery 5, a switch 7, a multivibrator IC 9 constituting a timer circuit, and a magnet relay 10. Select a multi-vibrator IC that is driven by DC voltage (e.g., NE555 equivalent), and a magnet relay that does not have any problem even if a current of up to 3A flows.

  An example of a specific circuit is shown in FIG. When the switch 7 is closed, a signal is input to the multivibrator IC 9 and a driving current of about 10 mA flows through the magnet relay 10 through 1 kΩ for a predetermined time. When the magnet relay 10 operates, the circuit surrounding the battery 5 and the heater 2 is closed, and a current flows through the heater 2 for a certain period of time. The unknown resistance R and the unknown capacitor C in FIG. 3 are changed according to the set time.

  In the timing diagram of FIG. 4, when the switch is turned on for a certain time, the time for the current to flow through the magnet relay is 1.1 RC. For this reason, for example, when it is desired that the current flow for 10 seconds, selecting R = 1 MΩ and C = 10 μF in FIG. Since C is practically about 100 pF to 10 μF and R is practically 10 MΩ or less, a material satisfying the requirements is selected between C = 1 to 10 μF and R = 1 to 10 MΩ.

  Here, when considering consumer applications, if the cutting edge 3a is 100 ° C. or higher, it is very dangerous and the range of use is limited. For example, the optimum temperature as the temperature of the blade edge 3a of the butter knife and the cake knife is 50 to 80 ° C., and about 60 ° C. is one standard. If the heat output of the heater is about 30 W or more, the temperature of the blade tip exceeds 60 ° C. within 10 seconds when the room temperature is 25 ° C. When the film heater 2 having a heat output of 30 W, a heating time of 10 seconds, and 3.6Ω is used, 9V type dry batteries such as alkali, manganese, and nickel are suitable.

  The electric capacity of the 9V type dry battery is about 10 kJ, and when it is driven at 30 W for 10 seconds, it can be used about 33 times with one battery. Currently, dry batteries suitable for various applications are commercially available, and there is also a method of extending the life by selecting an optimal dry battery in consideration of the size of the grip 4.

  The size of the cutting edge of a cake knife that is generally used at present is about 150 mm long, 20 mm wide, and 2 mm thick. Compared to the heat knife for testing, the heat capacity is about 2.5 times, but the actual temperature needs to be raised because the point where the cake and knife touch is at the tip of the sheet. Can be used without greatly changing the heat output.

  The same concept applies to butter knives, and the size of the knives may be slightly reduced to make the shape easier to use. For processing plastics and polystyrene foam, change the resistance value of the sheet resistance to be inserted according to the usage conditions, or change the temperature to match the purpose by using a circuit that allows continuous current to flow through the switch. Can be done.

  In addition, a thermocouple, etc. can be introduced at the blade tip at the same time to monitor the temperature, so that a circuit that generates a certain temperature can be built, and an LED is added to confirm that the heat is generated. A circuit is also conceivable.

  This heat knife can be applied not only to a primary battery which has been called a dry battery, but also to the use of a secondary battery if the problem of charging is solved.

It is a whole block diagram of a heat knife. It is a circuit block diagram for heat knives. It is a circuit diagram for heat knives. It is a timing diagram of the circuit for heat knives.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat knife 2 Film heater 3 Blade 4 Grip part 5 Dry cell 6 Cylindrical body 7 Switch 8 Connector part

Claims (3)

  In a heat knife having a blade connected to the heat generating part and a grip part for holding the blade, the blade includes a film heater constituting a part of the heat generating part, and the grip part supplies electricity to the film heater. A heat knife comprising an electric circuit for supplying.   The blade sandwiches a film heater having a thickness of 0.3 mm to 1.0 mm and a resistance of 1 Ω to 10 Ω in a metal plate, and the electric circuit includes a dry battery that constitutes a part of the heat generating portion. 2. The heat knife according to claim 1, further comprising a switch and a timer circuit.   The heat knife according to claim 2, wherein the heat generating unit selects a film heater and a dry battery having a heat output such that a blade edge temperature is 50 ° C. to 100 ° C.

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