A drilling system configured to install a tap assembly into a ship skin is disclosed. The drilling system comprises a remotely-operated underwater vehicle and a drilling assembly configured to be operated by the remotely-operated underwater vehicle. The drilling assembly comprises a frame comprising an attachment element configured to hold the drilling assembly to a surface of the ship skin. The drilling assembly further comprises a drill actuation system comprising a linear actuator attached to the frame and a rotary actuator, wherein an actuation of the linear actuator is configured to move the rotary actuator relative to the frame to install the tap assembly into the ship skin by driving the tap assembly with the rotary actuator and the linear actuator.

A device for determining a location on an elongated workpiece, characterized in that the device comprises: a frame movable in a first direction, preferably in a longitudinal direction of the workpiece, positioning means to position the frame in relation to the sides of the workpiece, movable means movable in a second direction, preferably in a transverse direction with respect to the frame, a measuring point, the movement in first direction and second direction used to move measuring point in said directions, measuring equipment for determining the location of the measuring point in transverse and longitudinal respect to the workpiece.

Provided is a magnetic holder which may be easily moved even after being released. The magnetic holder includes a fixed permanent magnet extending in one direction, a rotating permanent magnet extending in the one direction and rotatably fixed at both ends, first and second yokes covering both sides of the fixed permanent magnet and the rotating permanent magnet and extending in an up-down direction, and a coil wound around the first and second yokes, wherein, in a cross-section perpendicular to the one direction, the first yoke is in contact with an N pole of the fixed permanent magnet and the second yoke is in contact with an S pole of the fixed permanent magnet, and the coil, the rotating permanent magnet, and the fixed permanent magnet are arranged successively along the first and second yokes from an attachment surface of the first and second yokes attached to the attachment object.

A magnetic base for an electric machine tool, in particular for a magnetic core drilling machine, having a body in which is accommodated at least one first permanent magnet, the magnetic force of which combines with the magnetic force of at least one second permanent magnet to form a resultant holding force, wherein the at least one second permanent magnet is supported in the body such that it can rotate about a rotation axis through an angle of rotation between a first position in which the resultant holding force of the magnetic base is maximized and a second position in which the resultant holding force of the magnetic base is minimized, and having a controller for rotating the second permanent magnet between the first position and the second position.

A method for operating an electric core drilling machine, in particular a magnetic core drilling machine, comprising the steps: identification of a core drill bit detachably connected to the core drilling machine, by means of an information carrier associated with the core drill bit and an information receiver associated with the core drilling machine; detection of a load quantity of the core drill bit; determination of a wear value of the core drill bit on the basis of the value of the load quantity; issuance of an error value when the wear value exceeds a wear limit value; as well as issuance of a signal to indicate the necessity of replacing and/or repairing the core drill bit. In addition, the invention relates to a core drilling machine and a core drill bit for carrying out the method.

A magnetic base for an electric machine tool, in particular for a magnetic core drilling machine. A body that is accommodated in a receiving space. At least one first magnet coil constituting an electromagnet, a coil winding of the at least one first magnet coild being wound on a bobbin and a magnetic force of which is switchable between a maximum resultant holding force and a minimum resultant holding force. The coil winding of the magnet coil has two end sections that are each connected to a connecting cable that serves to make electrical contact between the magnetic coil and the electric machine tool. The body has a first side adapted to be coupled to the electric machine tool and has an opposite second side adapted to be placed on a workpiece that is to be processed. End sections of the coil winding are connected to the connecting cables.

A magnetic base for an electric power tool, in particular for a magnetic core drilling machine. The magnetic base having a base body, in which at least one first solenoid coil forming an electromagnet is accommodated in a receiving space, whose magnetic force is switchable between a maximum resulting holding force and a minimum resulting holding force. A first side that is adapted to be coupled with the electric power tool. An oppositely situated second side, which is adapted to be placed on a workpiece to be processed. The receiving space is designed such that an insertion of the at least one solenoid coil into the receiving space is possible only from the first side.

A pilot pin assembly is slidably receivable within a tool bit of a drill press. The pilot pin assembly includes a first pin defining an interior cavity, and a second pin at least partially received within the interior cavity of the first pin. A spring is positioned within the interior cavity for biasing the second pin toward an extended position relative to the first pin.

A drilling system configured to install a tap assembly into a ship skin is disclosed. The drilling system comprises a remotely-operated underwater vehicle and a drilling assembly configured to be operated by the remotely-operated underwater vehicle. The drilling assembly comprises a frame comprising an attachment element configured to hold the drilling assembly to a surface of the ship skin. The drilling assembly further comprises a drill actuation system comprising a linear actuator attached to the frame and a rotary actuator, wherein an actuation of the linear actuator is configured to move the rotary actuator relative to the frame to install the tap assembly into the ship skin by driving the tap assembly with the rotary actuator and the linear actuator.

The present invention provides, in an embodiment, a gear-shifting structure of power equipment, the gear-shifting structure comprising: first and second gears having shafts concentric with a first shaft, respectively, the first and second gears being positioned at different locations along the axial direction of the first shaft, the first and second gears having protrusions formed thereon, respectively, and the first and second gears freely rotating with regard to the first shaft; a clutch disposed concentrically with the first shaft between the first and second gears, the clutch being spline-coupled to the first shaft, and the clutch having engaging members formed thereon so as to protrude toward the first and second gears, respectively; an adjustment member configured to move the clutch toward the first gear or the second gear; a second shaft; and third and fourth gears having shafts concentric with the second shaft, respectively, the third and fourth gears being disposed to engage with the first and second gears and to rotate together with the second shaft. The engaging members of the clutch engage with the protrusion of the first gear or the second gear by means of the adjustment member.