Fuel-operated firing device and method for operating a firing device of this type

Patent metadata

Field	Value
Publication number	US-2018370004-A1
Application number	US-201616062141-A
Country	US
Kind code	A1
Filing date	Dec 20, 2016
Priority date	Dec 22, 2015
Publication date	Dec 27, 2018
Grant date	—

Abstract

The invention relates to a fuel-operated firing device for driving securing elements into a substrate, comprising at least one main combustion chamber for a fuel, a driving piston that can be driven out of the main combustion chamber in a firing direction by expandable gases, and a pre-chamber with which an ignition device is associated and in which a pressure acting on the main combustion chamber can build up prior to a fuel-air mixture being ignited in said main combustion chamber. In order to improve the efficacy and/or functionality during the driving in of securing elements, a detection system is associated with the driving piston, said detection system being connected to an electronic feedback control device for control purposes, in order to detect an initial position of the driving piston prior to a firing operation.

First claim

1 . A fuel-operated firing device for driving securing elements into a substrate, comprising at least one main combustion chamber for a fuel; a driving piston which can be driven out of the at least one main combustion chamber in a firing direction by expandable gases; a pre-chamber with which an ignition device is associated and in which a pressure acting on the at least one main combustion chamber can build up prior to a fuel/air mixture being ignited in the at least one main combustion chamber; and, a detection device associated with the driving piston; connected to an electronic feedback control device for control purposes, in order to detect an initial position of the driving piston prior to a firing operation.

2 . The fuel-operated firing device according to claim 1 , wherein the detection device associated with the driving piston comprises a piston end position sensor.

3 . The fuel-operated firing device according to claim 2 , wherein the piston end position sensor comprises a proximity sensor, a contact switch and/or an inductive switch.

4 . The fuel-operated firing device according to claim 1 , wherein the detection device associated with the driving piston comprises a piston position sensor.

5 . The fuel-operated firing device according to claim 4 , wherein the driving piston comprises grooves and the piston position sensor comprises a Hall effect sensor associated with the grooves on the driving piston.

6 . The fuel-operated firing device according to claim 1 , wherein the firing device comprises a control unit by which the firing energy is determined from a differential pressure between the at least one main combustion chamber and an ambient pressure.

7 . The fuel-operated firing device according to claim 1 , wherein the electronic feedback control device is connected for control purposes to a sensor device for detection of environmental conditions of the firing device.

8 . The fuel-operated firing device according to claim 1 , wherein an ignition device is arranged in the pre-chamber and/or in the at least one main combustion chamber.

9 . A method for operating a fuel-operated firing device for driving securing elements into a substrate, the device comprising at least one main combustion chamber for a fuel; a driving piston which can be driven out of the at least one main combustion chamber in a firing direction by expandable gases; a pre-chamber with which an ignition device is associated and in which a pressure acting on the at least one main combustion chamber can build up prior to a fuel/air mixture being ignited in the at least one main combustion chamber; and, a detection device associated with the driving piston; connected to an electronic feedback control device for control purposes, in order to detect an initial position of the driving piston prior to a firing operation, the method comprising controlling a quantity of fuel gas for injection into the pre-chamber and/or into the at least one main combustion chamber as a function of the initial position of the driving piston.

10 . The method according to claim 9 , comprising only injecting fuel gas into the at least one main combustion chamber and igniting the fuel gas if a piston displacement exceeds a predetermined limiting value.

11 . The method according to claim 9 , comprising only injecting fuel gas into the pre-chamber and igniting the fuel gas if a piston displacement exceeds a predetermined limiting value.

12 . The method according to claim 9 , comprising only injecting fuel gas into the pre-chamber and into the at least one main combustion chamber and igniting the fuel gas with a time difference, wherein the time difference is calculated on the basis of sensor signals.

13 . A computer program product with a program code for carrying out the method according to claim 9 .

14 . The computer program product of claim 13 wherein the program is executable in a common controller of the fuel-operated firing device.

15 . The fuel-operated firing device according to claim 2 , wherein the detection device associated with the driving piston comprises a piston position sensor.

16 . The fuel-operated firing device according to claim 3 , wherein the detection device associated with the driving piston comprises a piston position sensor.

17 . The fuel-operated firing device according to claim 15 , wherein the driving piston comprises grooves and the piston position sensor comprises a Hall effect sensor associated with the grooves on the driving piston.

18 . The fuel-operated firing device according to claim 16 , wherein the driving piston comprises grooves and the piston position sensor comprises a Hall effect sensor associated with the grooves on the driving piston.

19 . The fuel-operated firing device according to claim 2 , wherein the firing device comprises a control unit by the firing energy is determined from a differential pressure between the at least one main combustion chamber and an ambient pressure.

20 . The fuel-operated firing device according to claim 3 , wherein the firing device comprises a control unit by the firing energy is determined from a differential pressure between the at least one main combustion chamber and an ambient pressure.

Assignees

• Hilti Ag

Inventors

• Dittrich Tilo
• Jung Daniel
• Schmidt Dominik
• Heeb Norbert
• Bruggmueller Peter

Classifications

• B25C1/08 Primary

  operated by combustion pressure · CPC title