Hilti Aktiengesellschaft

Franz Büchel

Ulrich Schiestl

Norbert Heeb

Markus Frommelt

Thomas Sperrfechter

Jens Neumann

Thomas Granacher

Stefan Bönig

The invention relates to a combustion driven working tool having a combustion chamber (), a piston () guided in a cylinder (), an ignition system for igniting a fuel supplied to the combustion chamber () for driving the piston () and a fan () at least for ventilating the combustion chamber (). The running time and/or the speed of the fan () can be set as a factor of a measured temperature to realize a combustion driven working tool where an optimal ignition behavior can be set under changing working conditions, in particular under conditions of changing external temperature. A combustion chamber temperature is measured by a first temperature sensor () arranged on the combustion chamber () and supplied to a control unit (), which calculates the cooling time and/or the speed for the fan () as a factor of the measured combustion chamber temperature and supplies these values to the motor (). A second temperature sensor () is utilized for measuring the external temperature for the calculation of the cooling time or the speed of the fan ().

Temperature-controlled fan delayed shut-off

A piston holder for a drive piston () of a setting tool and having a circumferential adjusting surface () inclined toward a central axis () thereof so that a diameter of the adjusting surface () increase toward a rear, with respect to a setting direction () of the setting tool, end of the drive piston (), with the piston holder including contact elements () engageable with the adjusting surface (), and a spring () for biasing the contact elements into engagement with the adjusting surface ().

Holder for a drive piston of a setting tool

Growing community of inventors

Ruggell, Liechtenstein

Franz Büchel