Abstract: A wall saw comprising:—a carriage (2);—a saw arm (11) pivotally mounted to the carriage;—a rotatable spindle (10) rotatably mounted to the saw arm and configured for connection to a saw blade; and—an electric drive motor (13) for rotating the spindle. The rotor (36) of the drive motor comprises a rotor hub (66) which is operatively connected to the output shaft (14) of the drive motor through a safety clutch (67) so as to allow torque to be transmitted from the rotor hub to the output shaft via the safety clutch, the safety clutch being configured to allow mutual rotation between the rotor hub (66) and the output shaft (14) when said torque reaches a given threshold value. The safety clutch (67) is accommodated in a space inside the rotor hub (66).

Abstract: A wall saw comprising:—a carriage (2);—a saw arm (11) pivotally mounted to the carriage;—a rotatable spindle (10) rotatably mounted to the saw arm and configured for connection to a saw blade; and—an electric drive motor (13) for rotating the spindle. The rotor (36) of the drive motor comprises a rotor hub (66) which is operatively connected to the output shaft (14) of the drive motor through a safety clutch (67) so as to allow torque to be transmitted from the rotor hub to the output shaft via the safety clutch, the safety clutch being configured to allow mutual rotation between the rotor hub (66) and the output shaft (14) when said torque reaches a given threshold value. The safety clutch (67) is accommodated in a space inside the rotor hub (66).

Abstract: An adjustable length jacking column for supporting a cutting or drilling tool between spaced apart surfaces is disclosed. A speed drive serves to quickly adjust the column sections to an intermediate position closely corresponding to the distance between the spaced apart surfaces. A selectively engageable screw drive is configured to shift the column sections from the intermediate position to a secured position, in which the column length corresponds to fixed securement between the surfaces. The screw drive is drivingly connected between the column sections to shift the column sections relative to one another when engaged, and is drivingly disconnected from at least one of the column sections when disengaged so as to avoid interfering with relative shifting of the column sections by the speed drive.