Hilti Aktiengesellschaft

Eduard Pfeiffer

Markus Hartmann

Reinhard Schulz

Alexander John

Thomas Hofbrucker

Franz Moessnang

Stefan Hammerstingl

Stefan Schmid

Markus Holubarsch

Aaron Wiedner

Pierre Pallmer

Matthias Doberenz

Philipp Lorenz

Laurent-Sebastian Kock

Franz MÖSSNANG

Manuel Serf

A control method for a percussive hand-held power tool () includes the steps: detecting a switching state of an operating button (), detecting a temperature T using a temperature sensor (), activating an electropneumatic striking mechanism () in response to an actuation of the operating button (), an exciter () of the electropneumatic striking mechanism () being moved forward and backward along a working axis () at a repetition rate R, whereby a striker () coupled to the exciter () via a pneumatic chamber () is also moved. If the temperature T is greater than a limiting temperature Tc, the repetition rate R is continuously increased from idle up to a setpoint value (). A duration until reaching the setpoint value () is less than 10 cycles. If the temperature T is less than the limiting temperature Tc, a duration until reaching the setpoint value () is greater than 200 cycles.

Control method for a percussive hand-held power tool

The A hand-held power tool includes a tool holderfor holding a tool and a pneumatic striking mechanism for periodically generating impacts on the tool held in the tool holder. The striking mechanism includes a guiding tube, an exciter piston, a striker, a pneumatic chamber closed by the exciter piston and the striker in the guiding tube, and a compensating opening in the guiding tube for ventilating the pneumatic chamber. A cap covers the compensating opening on an outside of the guiding tube. The cap is open in an opening direction which is largely tangential to the guiding tube.

Hand-held power tool

A percussion mechanism contains a guide tube, an exciter piston, a hammer, a pneumatic chamber for coupling the hammer to the motion of the exciter piston, a striker, and a seat for the striker. The hammer has a striking point, defined by a striking surface of the striker when the striker lies against the seat. A check valve has an outlet opening and a closing mechanism for closing the check valve against an air flow from the interior of the guide tube. The outlet opening is arranged in such a way that the outlet opening is closed by the hammer during striking operation and otherwise is open.

Percussive power tool

The handheld power tool has a tool receptacle for accommodating a tool on a working axis () and an electric motor (). A pneumatic percussion mechanism () has an exciter, which is moved back-and-forth by the motor () periodically in parallel to the working axis (), a striker (), which is movable on the working axis () and is coupled via a pneumatic spring () to the exciter, and an anvil (), which is situated movably on the working axis () and is situated downstream from the striker () in the percussion direction (). The anvil () has a cylindrical anvil section () having a diameter and multiple channels () extending over the entire length () of the anvil section (). A cross-sectional area of the anvil section () is at most 5% less than a circular area defined by the diameter.

Handheld power tool

A pneumatic hammer mechanism is disclosed. The hammer mechanism features: a flying mass, which is movable along an impact axis; an impact surface, which limits a movement of the flying mass along the impact axis in the impact direction; an exciting piston, which limits a movement of the flying mass along the impact axis opposite from the impact direction; a pneumatic chamber between the flying mass and exciting piston; a drive for periodically moving the exciting piston with a stroke along the impact axis, wherein the flying mass is excited to a periodic movement between the impact surface and exciting piston. The stroke is selected as a function of a maximum length of the pneumatic chamber such that the periodic movement of the flying mass on the path between an impact on the impact surface and a minimum approach of the exciting piston intermittently has a velocity of zero.

Pneumatic hammer mechanism and control method

A pneumatic hammer mechanism is disclosed. The hammer mechanism includes: a flying mass; an impact surface which limits a movement of the flying mass along the impact axis in the impact direction; an exciting piston which limits a movement of the flying mass opposite from the impact direction; a pneumatic chamber between the flying mass and exciting piston; and a drive for periodically moving the exciting piston with a stroke along the impact axis. The following inequality applies for the mass (m) of the flying mass, a cross-sectional area (A) of the pneumatic chamber, the maximum length (L) of the pneumatic chamber, the stroke (H) of the exciting piston and an impact coefficient (q), if the hammer mechanism has an impact frequency (f) during percussive operation: 

Pneumatic hammer mechanism

A pneumatic hammer mechanism is disclosed. The hammer mechanism features: a flying mass, which is movable along an impact axis; an impact surface, which limits a movement of the flying mass along the impact axis in the impact direction; an exciting piston, which limits a movement of the flying mass along the impact axis opposite from the impact direction; a pneumatic chamber between the flying mass and exciting piston; and a drive for periodically moving the exciting piston with a stroke along the impact axis. The flying mass is excited to a periodic movement between the impact surface and a minimum approach of the exciting piston. A length ratio of the maximum length of the pneumatic chamber to the stroke is selected as less than 1.55.

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Halblech, Germany

Eduard Pfeiffer