Hilti Aktiengesellschaft

Reinhard Schulz

Werner Kleine

Eduard Pfeiffer

Alexander John

Hans-Werner Bongers-Ambrosius

Alexander Loeffler

Erwin Manschitz

Udo Hauptmann

Josef Obermeier

Martin Richter

Werner Kaibach

Hanspeter Schad

Maximilian Stock

Axel Neukirchen

Jens Frenzel

Edwin Schweizer

Ralf Ludwig

Helmut Nussrainer

Peter Sternberger

Wolfgang Lange

Holger Meinke

Alexander Löffler

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.

A hand-held power tool includes a motor-driven percussion mechanism. The percussion mechanism includes a guide tube () and a reciprocating driving member () displaceable in the guide tube () for driving, via a gas spring, an impact member () likewise displaceable in the guide tube (). The percussion mechanism further includes a motor-driven eccentric wheel () rotatable about an axis (D) which is spaced from the percussion mechanism axis (S) in a direction perpendicular to the percussion mechanism axis (S) by a distance (X). A connection rod () is eccentrically supported on the eccentric wheel () and connected to the driving member () for converting a rotational movement of the eccentric wheel () into a reciprocating movement of the driving member ().

Hand-held power tool with a pneumatic percussion mechanism

A hand-held power tool includes a percussion power tool includes a percussion piston () for applying blows to an anvil () axially displaceable in a guide tube () within limits defined by two, spaced from each other, stops () arranged in the guide tube (), a pneumatic percussion mechanism () for driving the percussion piston (), an air spring () for connecting the percussion piston () with the percussion mechanism (), and an impact ring () arranged coaxially with the anvil () outwardly thereof and having spaced from each other, inner radical flanks () located on opposite axial sides of the outer radial collar () provided on the anvil (), with the impact ring () freely axially displaceable, within limits, relative to the outer radial collar () and having an outer diameter smaller than a guiding inner diameter of the guide tuber (), and with a mass ratio of the impact ring () to the anvil () being equal at least 0.25.

Hand-held power tool with pneumatic percussion mechanism

A cup-shaped drill head with an inner conical surface () for force-locking connection with an exterior conical surface () of a driving drill shaft (), which at the leading end changes over into a cup base () with a center point (P), whereby in the change over from the cup base () to the inner conical surface () a lesser curvature (K) is present than at the center point (P).

Cup-shaped rock drill head

A tool for drilling and/or chiseling has a striking mechanism (6) within a guide tube (9) for reciprocating a first piston (7) and, via an air cushion, for reciprocating a second piston (19) within the guide tube. The second piston drives a driving anvil (17) in the driving direction. Between the first and second pistons (7, 19) the guide tube (9) has a series of radially extending first air passages (10) arranged in a first plane (E1) extending perpendicularly of the driving direction. A control body can be shifted over the guide tube (9) and is connected to the driving anvil (17). The guide tube (9) has a second series of radially extending second air passages (11) therethrough arranged in a second plane (E2) spaced from the first plane (E1) at a distance (A) opposite to the driving direction.

Tool for drilling and/or chiseling

A manually operable tool, such as a hammer drill, for drilling and/or removing material in at least one of brittle material and low ductile material, has a continuously rotatable chuck (8) and a motor driven striking mechanism (1) for transmitting impulse-like blows to a tool bit (9) held in the chuck (8). The tool includes members (5) for transmitting impulse-like blows composed of superimposed axially-directed blows and torsional blows to the tool bit (9) in the chuck for forming drilling blows. Further, an adaptor can be provided for attachment to the hammer drill containing the members (5) for affording the superimposed blows.

Manually operable tool for drilling and/or removing material in brittle

The tool for a tool holder of hand tools used for chiseling and/or percussion drilling has a chucking shank (9). This chucking shank (9) is provided with two rotary driving grooves (10) which are located diametrically opposite one another and open axially toward the free end of the chucking shank (9). Also, the chucking shank (9) has two diametrically opposite, axially closed locking grooves (11). In order to increase the total working surface decisive for the transmission of torque, two longitudinal grooves (12) are provided which are likewise arranged diametrically opposite one another and open axially toward the free end of the chucking shank (9). The length of these longitudinal grooves (12) exceeds the length of the locking grooves (11). The axes of symmetry (L) of the longitudinal grooves (12) are arranged at an acute angle (a) to the axes of symmetry (V) of the locking grooves (11). In addition, the flanks (12a) of the longitudinal grooves on the driving side extend in a straight line and tangentially relative to the base of the locking grooves (11) so as to form optimal working surfaces for the transmission of torque.

Tool and tool holder for hand-tool apparatus

The clamping shank (1) of a chisel-cutting and/or percussion boring tool bits has stop faces effective in the axial direction and in the circumferential direction. Entrainment faces (2), open towards a free end of the clamping shank (1) are located upstream of these stop faces in the direction of the cutting area of the tool bits. The radial dimension (r) of the essentially radially extending entrainment faces (2) is greater than their axial dimension (a). In cooperation with an appropriately designed tool bit receptacle, the entrainment faces (2) can carry such a large share of the torque, that the stop faces are effectively relieved or unloaded.

Tool and tool holder for manually operated tools

A tool bit has an axially extending shank section (1) to be inserted into a chuck in a manually-operated tool. The tool bit has an axially extending working section extending from the shank section. In the end region of the shank section remote from the working section there are first faces (2) acting in the axial direction and second faces (3) acting in the circumferential direction. In addition, the shank section (1) has entrainment faces (4a) spaced axially from the first and second faces toward the working section. The entrainment faces (4a) are located radially outwardly from the first and second faces (2, 3). The entrainment faces (4a) are part of grooves formed by a profiled section of the shank section and the grooves are open in the axial direction toward the first and second faces. The entrainment faces (4a) are radially spaced outwardly from the outer surface of the part of the shank section containing the first and second faces, so that they are able to transmit larger torques.

Tool bit and tool bit chuck for manually operated tools

An axially extending cutter bit has a shank extending between a trailing end (2, 7) arranged to be inserted into a tool chuck and a leading or working end (5, 8) with the shank between the trailing end and leading end being divided into a first section proceeding from the trailing end and a second section proceeding from the first section to the leading end. The second section is stepped inwardly from the first section. As a result, the energy throughput in passing shock waves is improved and higher material removal rates by the leading or working end are achieved.

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Munich, Germany

Reinhard Schulz