HOT AIR HAND TOOL

Description

[0001] The present invention relates to a hot air handheld device with a housing for accommodating at least one blower, a control device, actuating elements and a display and operating device, as well as a heating tube located on the housing with an integrated heating element and temperature sensor.

[0002] Such hot air hand tools are well known and are used in a variety of designs, for example for welding or shrinking plastics, drying objects, etc.

[0003] DE 10 2019 100 850 A1 relates to a hot air blower and a method for operating it. The document discloses a hot air blower comprising a blower unit for generating an airflow, a heating unit for heating the airflow, and a control unit connected to the blower unit and the heating unit. The control unit is configured to regulate or control the blower unit such that, when the heating unit is switched on, the blower unit generates an initial airflow reduced to a standard operating airflow. Furthermore, a method for operating the hot air blower is provided, comprising the steps of switching on the heating unit and generating an initial airflow reduced to a standard operating airflow.

[0004] DE 10 2020 200799 A1 relates to a distance heating device, in particular a hot air gun device, comprising a heat output unit for heating a surface, a sensor unit for determining at least one piece of information relating to the surface, and a control unit for controlling the heat output unit. It is proposed that the information includes at least one component other than the surface temperature and that the control unit triggers at least one function based on the information in at least one operating state.

[0005] EP 1 956 317 A2 relates to a heating device and a method, wherein the heating device, such as a hot air gun or a heating unit, has a surface temperature sensor for measuring the surface temperature of the workpiece to be heated.

[0006] JP S61 217648 A concerns another hot air gun with a temperature sensor.

[0007] DE 20 2017 103466 U1 concerns a hot air handheld device with a contactless user communication interface.

[0008] Especially when used as a hot air welding machine, it is important to know the temperature at the welding point. This is usually at a specific distance in front of the hot air outlet of the heating tube. Additionally, the hot air flow rate, which is often adjustable on these machines, must be taken into account. To measure the temperature, a temperature sensor is located inside the heating tube in the area between the heating element and the outlet, typically right at the end of the heating element.Especially when using such temperature-controlled hot air hand tools in industries with very high demands on process traceability and accuracy, for example in the transportation industry, and particularly in the aerospace industry, it is essential that the temperature displayed on the hot air hand tool corresponds to the temperature at which the work (welding / shrinking) is actually performed. Due to thermal losses, the temperature at the air exit from the heating tube is already lower than at the measuring point in the airflow just behind the heating element. Therefore, a calibration curve is stored in the control unit that regulates the hot air temperature. This curve calculates the actual temperature at the air exit from the temperature measured by the sensor. A linear relationship is assumed, and the slope and offset are determined and stored based on two measurement points.The display on the hot air handheld device will then only show the measured temperature.

[0009] The moment different nozzles are attached to the heating pipe, the temperature at the welding point changes depending on the nozzle. Even if welding takes place at a different location, at a different distance from the heating pipe outlet, for whatever reason, the displayed temperature will not correspond to the actual temperature at the work site.

[0010] The present invention therefore aims to propose a way to display the actual temperature at a defined point in front of the heating tube for any application.

[0011] The claimed subject matter is defined in the independent claims. Advantageous embodiments are described in the dependent claims.

[0012] According to one aspect of the present disclosure, calibration curves are stored in the control unit upstream of the heating tube, depending on a plurality of different airflow options for the hot air exiting the heating tube. The hot air handheld device with the control unit is designed, after the respective airflow after exiting the heating tube has been selected, to display the air temperature at the corresponding point on the display, according to the calibration curve of the airflow. These calibration curves are determined linearly, for example, by corresponding measurements at a predetermined airflow rate using a lower and an upper temperature value, and stored for the respective airflow option. This is generally done with a total of four values ​​(upper and lower temperature values ​​for upper and lower airflow rates).This allows for a correct temperature display, corresponding to the actual conditions, at different nozzles or at specific distances in front of the heating tube without nozzles, after the user has selected the respective application.

[0013] Accordingly, a method for operating a hot air handheld device according to the invention can comprise the following steps: providing the hot air handheld device; determining the airflow after exiting the heating tube, wherein (a) calibration curves are stored in the control unit depending on a plurality of different airflow options for the hot air exiting the heating tube, or, instead of the plurality of calibration curves stored in the control unit, these are stored on a mobile communication device and the respective selected calibration curve can be loaded from the mobile communication device to the control unit via a communication interface; and displaying the air temperature at the location corresponding to the airflow according to the calibration curve of the airflow on the display.

[0014] Preferably, calibration characteristics are stored in the control unit, depending on the nozzles that can be attached to the heating pipe.

[0015] According to a particularly preferred embodiment of the invention, a communication interface for wireless communication is provided in the hot air handheld device for the wireless transmission of data to and from a mobile communication device. The majority of the airflow options can be displayed and selected via the display unit. The various airflow options are shown on the display of the mobile communication device and can be selected by the operator. The calibration curves corresponding to the airflow options can already be stored in the control unit of the hot air handheld device and are selected via the communication device. Alternatively, the calibration curves are stored on the mobile communication device, selected there, and the selected calibration curve is transferred to the control unit and stored there for this application.Preferably, calibration characteristics stored on the mobile communication device are loaded from the mobile communication device to the control unit, according to further training.

[0016] According to a particularly preferred embodiment of the hot air handheld device, it is possible to calculate a new calibration curve from measured temperature values ​​at a position relevant to the respective airflow, using a formula stored in the communication device and corresponding airflow volume. This curve can then be transferred to the control unit and stored there for this specific application, as described above. This design is particularly advantageous when either a new nozzle for which no calibration curve exists is to be used, or when the temperature at a very specific point in front of the heating tube is important and therefore needs to be adjustable and displayed. Alternatively, it is also possible for the formula to be stored in the control unit, with only the measured values ​​being transmitted from the communication device to the control unit.

[0017] For this purpose, the temperature at the desired location can be determined using an external temperature probe, which is either connected to a corresponding display so that the data can be entered into the mobile communication device for calculating the calibration curve, or is directly connected to the mobile communication device. This feature also allows a user to define their calibration curve precisely for the temperature range in which they typically operate the hot air handheld device.

[0018] The hot air handheld device according to the invention thus allows for easy adaptation to different applications, regardless of whether these applications were already taken into account when the hot air handheld device was delivered. Either the existing calibration curves can be accessed or a new calibration curve can be created by means of additional measurements.

[0019] The features and combinations of features mentioned above in the description, as well as those subsequently mentioned in the figure description and / or shown in the figures alone, are usable not only in the combinations specified, but also in other combinations or individually. Individual features of the independent claims may also be replaced by other disclosed features or combinations of features. All features and / or advantages arising from the claims, the description, or the drawing, including design details, spatial arrangement, and process steps, may be essential to the invention both individually and in various combinations. The following figures illustrate: Figure 1 is a perspective view of a hot air handheld device with a nozzle mounted on the heating tube, communicating with a mobile telecommunications device; Figure 2 is a sectional view through the hot air handheld device according to Figure 1 with a schematic representation of the electrical communication paths as a block diagram; and Figure 3 the arrangement for recording a new calibration characteristic curve; Figure 4 a flowchart of a method for operating a hot air handheld device.

[0020] The one in Figure 1 The hot air handheld device 1 shown is an externally conventional hot air handheld device 1 with a housing 2, handle 3, and a display and operating device 4 in the form of an input screen and a power switch 5 (Figure 2) on the housing 2. Inside the housing 2 is a blower 6 ( Figure 2 ), through which air is supplied via the heating tube 7 and a nozzle 8 attached to the heating tube 7. Inside, as in Figure 2 A heating element 9 is shown. The embodiment shows the operation of the hot air handheld device 1 by means of a mobile telecommunications device 10 with a display screen 14. Without this, the hot air handheld device can be operated accordingly via the display 4, which is also designed as an input screen.

[0021] In the Figure 2The diagram schematically depicts a control circuit with a control unit 11, which receives signals from a sensor 12 at the hot air end of the heating element 9. Linear calibration curves are stored in the control unit 11, which assign an actual temperature value, displayed on the screen 4, to the respective measured value from the sensor 12. The calibration curve is also influenced by the airflow, resulting in a different calibration curve depending on the airflow. The control unit 11 thus also controls and regulates the blower 6 and outputs the respective temperature on the screen 4. The control unit 11 also controls and regulates the heating element 9. When used with the mobile telecommunications device 10, the control unit 11 also has a telecommunications interface that communicates with the mobile telecommunications device 10.This allows all possible stored calibration curves to be displayed on the telecommunications device 10, for example, by the corresponding nozzle symbol or a distance from the outlet end of the heating tube 7, instead of being displayed on the input screen 4. The operator then selects the calibration curve stored in the control unit 11 for the application, and the selection signal is transmitted to the telecommunications interface. This design of the hot air device with a communication interface also allows the corresponding calibration curves to be stored not all in the control unit 11, but on the mobile telecommunications device 10, and only the respective application to be transmitted to and stored in the control unit 11.

[0022] In the Figure 3A further temperature sensor 13 is shown, which determines the temperature of a new nozzle 8 and transmits it to the mobile telecommunications device 10. By recording temperature values ​​at specific air volumes, the calibration characteristic curve required for this application can be calculated using a formula stored on the mobile telecommunications device 10 and transmitted to and stored in the control unit 11. This allows new applications to also be provided with an accurate temperature reading. It is also conceivable that the temperature readings from sensor 13 could be manually entered into the telecommunications device 10.

[0023] In the Figure 4Figure 100 shows a flowchart of a process for operating a hot air handheld device. In a first step S101, a hot air handheld device 1 is provided. This can be a hot air handheld device as described above. In step S102, the air flow after exiting the heating tube 7 is defined (or specified or determined), wherein (a) calibration characteristics are stored in the control unit 11 upstream of the heating tube 7, depending on a plurality of different air flow possibilities, or (b) instead of the plurality of calibration characteristics stored in the control unit 11, these are stored on a mobile communication device 10, and the respective selected calibration characteristic can be loaded from the mobile communication device 10 to the control unit 11 via a communication interface.In other words, the calibration curves are alternatively stored on the mobile communication device, selected there, and the selected calibration curve is transferred to the control unit and stored there for this application. In step S103, the air temperature at the point corresponding to the air duct is displayed on screen 4 according to the calibration curve of the air duct.

Claims

1. Hand-held hot air device (1) with a housing (2) for at least a fan (6), a control device (11), actuating elements and a display (4) and operating device as well as a heating tube (7) arranged at the housing (2) with an integrated heating element (9) and temperature sensor (12), characterized in that in the control device (11) as a function of a plurality of different air guide options for the hot air emerging from the heating tube (7) after the heating tube (7) there are provided calibration curves, and the hand-held hot air device (1) with the control device (11) is configured to, after setting the respective air guide at the outlet from the heating tube (7), output the air temperature at the location corresponding with the air guide on the display (4) in accordance with the calibration curve of the air guide.

2. Hand-held hot air device (1) according to claim 1, characterized in that in the control device (11) calibration curves as a function of nozzles (8) to be attached to the heating tube (7) are provided, and the hand-held hot air device (1) with the control device (11) is configured to, after setting the nozzle (8) used, output the air temperature at the outlet of the nozzle (8) on the display (4) in accordance with the calibration curve of the nozzle (8) used.

3. System comprising a hand-held hot air device (1) according to claim 1 or 2 and a mobile communication device (10), characterized in that the hand-held hot air device (1) comprises a communication interface for wireless communication for wireless transmission of data from and to the mobile communication device (10), wherein the calibration curves corresponding to the air guide options are provided on a display (4) on the mobile communication device (10) and are selectable.

4. System according to claim 3, characterized in that calibration curves stored on the mobile communication device (10) can be loaded from the mobile communication device (10) to the control device (11).

5. System comprising a hand-held hot air device (1) according to claim 1 or 2 and a mobile communication device (10), characterized in that the hand-held hot air device (1) comprises a communication interface for wireless communication for wireless transmission of data from and to the mobile communication device (10), wherein measured temperature values at a relevant location for the respective air guide at a corresponding assigned air volume can be loaded from a mobile communication device (10) to the control device (11), which calculates and stores a new calibration curve based on a formula stored therein.

6. System comprising a hand-held hot air device (1) according to claim 1 or 2 and a mobile communication device (10), characterized in that instead of the plurality of calibration curves being stored in the control device (11) of the hand-held hot air device (1) these are stored on the mobile communication device (10) and the respective selected calibration curve can be loaded from the mobile communication device (10) to the control device (11) via a communication interface.

7. System according to claim 6, characterized in that the mobile communication device (10) calculates and stores a new calibration curve from measured temperature values at a position relevant for the respective air guide at a corresponding assigned air volume based on a formula stored in the communication device (10).

8. Hand-held hot air device (1) with a housing (2) for at least a fan (6), a control device (11), actuating elements and a display (4) and operating device as well as a heating tube (7) arranged at the housing (2) with an integrated heating element (9) and temperature sensor (12), characterized in that the hand-held hot air device (1) with the control device (11) is configured to, after setting the respective air guide at the outlet from the heating tube (7), output the air temperature at the location corresponding with the air guide on the display (4) in accordance with a calibration curve of the air guide, wherein the hand-held hot air device (1) comprises a communication interface for wireless communication for wireless transmission of data from and to a mobile communication device (10), wherein as a function of a plurality of different air guide options for the hot air emerging from the heating tube (7) after the heating tube (7) calibration curves are stored on the mobile communication device (10) and the hand-held hot air device (10) is configured to load the respective selected calibration curve from the mobile communication device (10) to the control device (11) via the communication interface.

9. Method (100) for operating a hand-held hot air device (1) according to any of the preceding claims, comprising the steps of: - providing the hand-held hot air device (1) (S101); - setting the air guide at the outlet from the heating tube (7), wherein in the control device (11) as a function of a plurality of different air guide options for the hot air emerging from the heating tube (7) after the heating tube (7) there are provided calibration curves (S102); and - outputting the air temperature at the location corresponding with the air guide on the display (4) in accordance with the calibration curve of the air guide (S103).

10. Method (100) for operating a hand-held hot air device (1) according to any of the preceding claims, comprising the steps of: - providing the hand-held hot air device (1) (S101); - setting the air guide at the outlet from the heating tube (7), wherein as a function of a plurality of different air guide options for the hot air emerging from the heating tube (7) after the heating tube (7) calibration curves are stored on a mobile communication device (10) and the respective selected calibration curve can be loaded from the mobile communication device (10) to the control device (11) via a communication interface (S102); and - outputting the air temperature at the location corresponding with the air guide on the display (4) in accordance with the calibration curve of the air guide (S103).