Wacker Construction Equipment Ag

Wacker-werke Gmbh & Co Kg

Mirko Lysek

Wolfgang Schmid

Rudolf Berger

Thomas Schmidbauer

The invention relates to a pneumatic percussive tool for a paving breaker and/or a hammer drill comprising a drive piston which is displaceable both backwards and forwards by a crankshaft and arranged in a percussion piston which is displaceable both backwards and forwards. A hollow chamber is connected to a compensating chamber by an idling air channel and embodied between the drive piston and the percussion piston in order to receive a pneumatic spring. A valve is arranged in the idling air channel, the opening and closing position thereof depending on the rotational speed of the crankshaft. If the rotational speed of the crankshaft falls below a predetermined value, the valve opens the connection between the hollow chamber and the compensating chamber so that a pneumatic spring can no longer be to embodied in the hollow chamber and the pneumatic percussion tool is placed in a idling position.

Pneumatic percussive tool with a movement frequency controlled idling position

The invention relates to a demolition hammer and/or hammer drill comprising a percussion generating device having a percussion piston moving axially back and forth. In a main percussion mode, the percussion piston impinges upon a tool which can move along a limited axial path straight into a main percussion direction. In a free percussion mode, the percussion piston indirectly impinges upon a percussion changing device, and by means thereof upon the tool, in a free percussion direction opposite to the main percussion direction. The impact surface of a tool shaft and the impact surface of a free percussion ram are placed opposite an impact surface of the percussion piston in such a way that the free percussion ram is removed from the effective area of the percussion piston by a return spring in the main percussion position. Under the effect of the return spring, the percussion ram is simultaneously supported on a gear member of the percussion changing device, which projects with an extension into the motion path of a stop surface provided in the tool. The stop surface reaches the extension when it has moved away from the effective area of the percussion piston in an idle running state of the tool shaft. If the movement of the tool is continued, the stop surface impinges upon the gear member against the effect of the return spring and relocates the free percussion ram in the effective area of the percussion piston by overcoming the spring force.

Demolition hammer and/or hammer-drill with a percussion device suitable for releasing clamped objects by striking

A pneumatic percussive tool for a paving breaker and/or a hammer drill, provided with a drive piston which is axially displaceable both backwards and forwards, comprising a guide sleeve and a piston bottom supporting the guide sleeve. A percussion piston can be displaced axially in the guide sleeve of the drive piston with the piston head thereof in percussive mode. During the transition from percussive to idling mode, the piston head slides out of the guide sleeve in such a way that the percussion piston is substantially maintained in the idling mode in an axially displaceable manner by means a stationary part of the percussion tool housing as opposed to being so maintained in the guide sleeve. The axial length of the drive piston can be reduced, whereby the mass of the drive piston and vibrations caused by the movement of the drive piston in the percussive and idling mode can also be reduced.

Pneumatic percussive tool with a short working drive piston

The invention relates to a pneumatic percussive mechanism for a percussion drill and/or a drill hammer. The inventive mechanism comprises, housed in the housing of the percussive mechanism, an axially reciprocating percussion piston. A drive piston is axially reciprocated in a guide cylinder of said percussion piston. The guide cylinder is provided on its inner face with one or more air compensation pockets. At least one idle opening extends through the guide cylinder. In the percussive action, the idle opening does not communicate with the ambience while in the idle mode the idle opening can be displaced via an idle channel that leads to the ambience and thus connects a cavity that receives a pneumatic piston with the ambience by way of the idle opening. The air compensation pockets and the idle openings allow and optimization of the piston return behavior and of the idle operation of the percussive mechanism.

Pneumatic piston percussive mechanism with a hollow percussion piston

An impacting device is capable of being used in an impact hammer and/or a drill for releasing by impact tools blocked in rocks. An impact impetus supplied by an impact piston is modified via an impact-deflecting device having a sliding lever and a deflecting lever, such that the impact is carried out in a releasing impact direction opposite the normal impact direction and is transmitted to a tool by a slide and a locking lever. The tool is released after a few strokes produced by the impact piston. The impact device is suitable for both unilateral air springs and double air springs.

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Munich, Germany

Mirko Lysek