Apparatus for controlling the number of revolutions of an engine

An apparatus for controlling the number of revolutions of an engine of a construction machine comprising:

• at least one grip sensor including an electrical portion of a corresponding control lever adapted to control actuation of a working tool of the construction machine, said grip sensor adapted to detect the approach of an operator toward the gripping portion of said control lever;
• control means adapted to output an acceleration signal in response to an output signal from the grip sensor when the operator approaches said gripping portion in order to raise the current number of revolutions of the engine to a level higher than the number of revolutions of the engine in an idle rotational state;
• and
• driving means for raising the number of revolutions of the engine to a level of the last-mentioned higher one in response to the acceleration signal from said control means.

An apparatus for controlling the number of revolutions of an engine of a construction machine in which said engine is operated at a constant high speed when working is performed, comprising:

• proximity sensing means incorporated in a gripping portion of a control lever adapted to control actuation of a working tool on said construction machine, said sensing means adapted to detect the approach of an operator of said construction machine toward said gripping portion of said control lever;
• control means for outputting a deceleration signal in response to an output signal from the grip sensor when the operator does not approach said gripping portion in order to reduce the current number of revolutions of the engine to a level lower than the number of revolutions of the engine at said high speed;
• and
• driving means for reducing the number of revolutions of the engine to said lower level in response to the deceleration signal from said control means.