Hilti Aktiengesellschaft

Alexander John

Reinhard Schulz

Eduard Pfeiffer

Bernhard Sander

Markus Hartmann

Albert Binder

Harald Schmitzer

Christoph Würsch

Hans Böni

Alexander Grosser

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

The machine tool includes a pneumatic percussion mechanism having a cup-shaped exciter cylinder () with an inner chamber () which is open in the direction of impact (), and a free piston () which is movable in the inner chamber (). A recess () and at least one ventilation opening (), spaced at a distance from the recess () in the direction of impact (), are provided in a shell-type wall () of the inner chamber (). The free piston () includes a sealing element () which seals off the at least one ventilation opening () when the sealing element () is oppositely situated from the at least one ventilation opening (), and which in the region of the recess () is separated at a distance from the shell-type wall () when the sealing element () is oppositely situated from the recess.

Machine 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; 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.

A hand-held power tool () includes a linear motor () having a rotor () which is movable along a percussion axis (A) in an axially limited manner between two reversal points (W) and which can be driven by the striking piston () of the power tool with the intermediary of an air spring (), sensors designed for determining the actual state of the rotor () and connected to a computer () connected via power electronics () to at least one field coil () of the linear motor (), with the rotor () being displaced against a contact element () at least at one reversal point (W) and being pressed against the contact element electromagnetically; and a control process for the hand-held power tool.

Hand-held power tool with air spring percussion mechanism, linear motor, and control process

A clamping device connects two, axially harmonically oscillating components which oscillate, as a result of their respective plane surfaces impacting each other with a frequency &#x3c9; in the form of a stationary longitudinal wave with a distance A between two nodes K. The clamping device includes an axially extending springy gripping yoke having two clamping elements. The two clamping elements are located at opposite ends of the gripping yoke. The two clamping elements are spaced apart from each other by a distance corresponding to the distance A between the two nodes K of the longitudinal wave.

Growing community of inventors

St. Johann-Ob Hohenburg, Austria

Alexander John