EP2656973B1 - Tool for placing fastening elements - Google Patents

Description

Technical area

The invention relates to a working device for setting fastening elements in a substrate, with a fuel container and a metering device, is supplied via the fuel from the fuel container to a combustion chamber in which an ignitable mixture is ignited to set a fastener, and with a temperature sensor. The invention further relates to a method for operating such a working device.

State of the art

From the German patent application DE 10 2008 000 973 A1 is a hand-held implement with a temperature sensor for monitoring the device or ambient temperature known.

The document EP 2090404 A1 discloses an implement with a temperature sensor.

Presentation of the invention

The object of the invention is to avoid unwanted interference in the operation of a working device according to the preamble of claim 1 or to reduce the number thereof.

The object is in a working device for setting fasteners in a substrate, with a fuel container and a metering device, is supplied via the fuel from the fuel container to a combustion chamber in which an ignitable mixture is ignited to set a fastener, and with a temperature sensor , solved in that the working device comprises a container temperature sensor and a metering temperature sensor. The implement is preferably a hand-held implement for setting bolts operated with fuel gas. Therefore, the implement is also used as a gas powered bolt gun or Bolt push tool called. The fuel in the fuel container is preferably present as a liquid fuel gas, which evaporates in a technically disadvantageous, critical operating condition, which is also referred to as Vapor Lock state or Vapor Lock state, in the metering device and occupies a larger volume. This can lead to incorrect dosing quantities depending on the type of dosage. This is particularly the case with volumetric and time-controlled doses and can lead to significant ignition disturbances in the operation of the implement. Due to the inventive combination of a container temperature sensor with a dosing temperature sensor in the working device critical operating conditions, in particular Vapor Lock states can be detected and avoided in a simple manner. As a result, the operational safety during operation of the working device according to the invention can be increased. In addition, the arrangement of the fuel container is simplified relative to the metering device in the working device.

A preferred embodiment of the working device is characterized in that the container temperature sensor and the metering temperature sensor are connected in terms of control with a measured value detection unit. In the Meßwertertassungseinheit recorded by the container temperature sensor and the dosing temperature sensor data are evaluated and stored. Thereafter, appropriate measures can be taken internally to avoid unwanted critical operating conditions or to reduce their number.

A further preferred embodiment of the working device is characterized in that the container temperature sensor is arranged on or in the fuel container. By means of the container temperature sensor, the temperature of the fuel in the fuel container is preferably detected.

A further preferred embodiment of the working device is characterized in that the metering temperature sensor is arranged on or in the metering device. With the metering temperature sensor, the temperature of the fuel is preferably detected, which is supplied via the metering device to the combustion chamber.

In a method for operating a work implement described above, the above-mentioned object is alternatively or additionally achieved in that the data acquired by the container temperature sensor and the dosing temperature sensor are used internally to detect and / or avoid critical operating conditions. The The method according to the invention can also be advantageously used in the development of working implements described above.

A preferred embodiment of the method is characterized in that from the data recorded by the container temperature sensor and the dosing temperature sensor, a temperature difference is formed, which is compared with a maximum permissible limit temperature difference. In the context of the present invention, it has been recognized that for the occurrence of a vapor-lock condition, the absolute temperature of the fuel in the metering device is less responsible than the temperature difference between the fuel container and the metering device. The maximum permissible limit temperature difference depends on the vapor pressure curve of the gas composition used and is preferably stored as a fixed value in a memory of the working device, which is accessed during the process. In an alternative embodiment, the composition of the gas is coded on the gas container and readable by the implement, in which case the maximum permissible limit temperature difference for the respective gas composition is stored in a memory. In further alternative embodiments, moreover, the pressure and / or the temperature of the gas in the gas container is determined, for example by means of a pressure sensor and the container temperature sensor, and taken into account in the determination of the maximum permissible limit temperature difference.

A further preferred embodiment of the method is characterized in that a signal is emitted as soon as the maximum permissible limit temperature difference is exceeded. If the maximum permissible limit temperature difference is exceeded, then it can be assumed that fuel already evaporates in the metering device. This can cause the dosage to be too low.

A further preferred embodiment of the method is characterized in that the signal is delivered in the form of an optical, haptic and / or acoustic signal to the user of the working device. The optical signal can be displayed, for example, in the form of a red flashing light on the outside of the implement. For example, the haptic signal may be presented in the form of additional vibration of the handle of the implement. The acoustic signal may be displayed, for example, in the form of a warning tone generated in the implement.

A further preferred embodiment of the method is characterized in that the signal is used internally in the device to reduce the detected temperature difference. Thus, for example, device-internal cooling measures for the metering device and / or the combustion chamber can be initiated.

A further preferred embodiment of the method is characterized in that a device-internal fan is turned on to reduce the detected temperature difference. For cooling the combustion chamber or the mixture in the combustion chamber, a device-internal fan or fan can be used. Alternatively or additionally, Peltier elements can be used.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, various embodiments are described in detail.

FIG. 1 shows a simplified illustration of the working device according to the invention.

embodiments

In FIG. 1 is an inventive implement 1 with a housing 2 shown greatly simplified. The implement 1 is designed as a hand-held bolt setting tool with a handle 4 to which the bolt setting device 1 can be tacked for driving a fastener, which emerges from the bolt-setting device 1 at a bolt-guiding end 5 and can be driven into a ground.

The fasteners used are preferably provided via a device-internal magazine 6, which is mounted in the vicinity of the bolt guide end 5 of the bolt-firing device 1. From the magazine 6, the fasteners are preferably automatically removed individually and provided at the bolt guide end 5.

The energy required for driving the fastening elements into the ground is provided in a fuel tank 8 in the interior of the bolt setting device 1. The fuel container 8 preferably contains liquid fuel gas and is therefore also referred to as a gas container or gas cartridge.

The fuel container 8 is via an adjustable or controllable metering device 10 and a gas line 11 with a combustion chamber or a combustion chamber 12 connectable. The metering device 10 preferably comprises a metering valve, via which the amount of gas supplied to the combustion chamber, for example, volumetrically or time-dependent, can be controlled.

In the combustion chamber 12, fuel, in particular gas, from the fuel container 8 is mixed with air to form a combustible mixture which is ignited to drive a fastener such as a bolt or a nail into the ground. The energy required for driving is transmitted, for example via a (not shown) working piston from the combustion chamber 12 to a fastener on the bolt guide end 5.

In the combustion chamber 12, a device 14 is arranged, which serves to generate turbulence in the combustion chamber 12, to flush the combustion chamber 12 and / or to cool. The device 14 comprises a fan 15, which is driven by an electric motor 18. The electric motor 18 is controlled via an electronic control device 20.

The control device 20 comprises a measured value acquisition unit, from which two lines 21, 22 emanate. Via the line 21, a container temperature sensor 31 is connected to the control device 20. Via the line 22, a metering temperature sensor 32 is connected to the control device 20.

The tank temperature sensor 31 serves to detect the temperature of the fuel in the fuel tank 8. The metering temperature sensor 32 serves to detect the temperature of the fuel or gas, which is supplied to the combustion chamber 12 via the metering device 10.

In gas-powered bolt guns, a critical operating condition may occur in which liquid fuel gas evaporates in the metering device and occupies a larger volume. This critical operating condition is also referred to as Vapor Lock condition and may, especially at volumetric and timed dosages, result in incorrect metered quantities since the metered quantities are matched to the liquid phase of the fuel. This in turn can lead to significant ignition problems. With the aid of the two sensors 31 and 32, a transition of the fuel gas from the liquid to the gaseous phase in the metering device 10 can be detected.

The temperature data acquired by the two sensors 31 and 32 are evaluated and stored in the measured value detection unit in the control device 20. The critical operating state, which is also referred to as vapor lock state, a characteristic temperature difference between the fuel tank 8, in which the liquid fuel gas is provided, and the metering device 10 are assigned, via which the liquid fuel gas is supplied to the combustion chamber 12.

With the two sensors 31 and 32, the temperature difference between the fuel tank 8 and the doser device 10 can be monitored during operation of the implement 1. In the measured value acquisition unit, the detected, actual temperature difference is compared with a maximum permissible temperature difference. As soon as the maximum permissible temperature difference, which is also referred to as limit temperature difference, is exceeded, the measured value acquisition unit outputs a signal which is further processed internally in the device.

The signal for exceeding the maximum permissible temperature difference can, for example, be visibly displayed on the outside of the implement 1 to the user via a red warning light. Alternatively or additionally, device-internal measures for reducing the temperature difference can be carried out. For this purpose, for example, the fan 15 can be turned on to cool the mixture in the combustion chamber 12. In addition, Peltier elements can be used to cool the combustion chamber 12.

Claims (10)

1. Tool for setting fastening elements in a substrate, comprising a fuel container (8) and a metering device (10) by means of which fuel is fed from the fuel container (8) to a combustion space (12) in which an ignitable mixture is ignited in order to set a fastening element, and comprising a temperature sensor, characterised in that the tool (1) includes a container temperature sensor (31) and a metering temperature sensor (32).
2. Tool according to claim 1, characterised in that the container temperature sensor (31) and the metering temperature sensor (32) are connected to a measured-value acquisition unit for control purposes.
3. Tool according to one of the preceding claims, characterised in that the container temperature sensor (31) is arranged on or in the fuel container (8).
4. Tool according to one of the preceding claims, characterised in that the metering temperature sensor (32) is arranged on or in the metering device (10).
5. Method of operating a tool (1) according to one of the preceding claims, characterised in that the data acquired by the container temperature sensor (31) and the metering temperature sensor (32) are used inside the tool to detect and/or to prevent critical operating states.
6. Method according to claim 5, characterised in that a temperature difference is formed from the data acquired by the container temperature sensor (31) and the metering temperature sensor (32) and is compared with a maximum permissible limiting temperature difference.
7. Method according to claim 6, characterised in that a signal is emitted as soon as the maximum permissible limiting temperature difference is exceeded.
8. Method according to claim 7, characterised in that the signal is emitted to the user of the tool (1) in the form of a visual, tactile and/or audible signal.
9. Method according to claim 7 or claim 8, characterised in that the signal is used inside the tool to reduce the detected temperature difference.
10. Method according to claim 9, characterised in that a fan inside the tool is switched on to reduce the detected temperature difference.

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