Holder for a rotary tool which holder is formed with a holder body comprising a rear drive end and a front connection end having a connection thread for the connection of the tool. The holder comprises a thrust collar having a flat contact surface facing a connection end of the holder. The holder comprises an axially movable operating means, a number of restraint elements placed in one or more spaces in the holder body which restraint elements in a first axial position of the operating means are prevented from radial movement in said spaces and which restraint elements in a second axial position of the operating means allow radial movement in said spaces. Each one of said spaces for the restraint elements is limited in the axial direction by a front limiting wall and a rear limiting wall, which two limiting walls are parts of the holder body.

A drill bit has a cutting portion having an annular portion, where the annular portion has a first end on which is disposed a cutting element and a second end that includes an outer insertion element and a stop shoulder. The drill bit has a drill shaft portion having a cylindrical drill shaft, where the drill shaft has an inner insertion element with an end face on a side of the drill shaft facing the cutting portion. The outer insertion element and the inner insertion element together form a plug connection in an insertion direction that is parallel to the axis of rotation and the insertion elements are connectable to each other via a pin element that is movable into a slot-shaped recess. The pin element is attached to an outside of the inner insertion element and the outer insertion element has the slot-shaped recess.

A hole saw, including a rotatable drill bit, a plurality of rotatable saw jaws disposed around the drill bit to encase at least a portion of the drill bit therewithin when the rotatable saw jaws are in a closed position, a fixed locking collar portion disposed at base ends of the plurality of rotatable saw jaws, and a movable locking collar portion to move with respect to the fixed locking collar portion, such that the plurality of rotatable saw jaws pivot away from each other into an open position as the movable locking collar portion moves away from the fixed locking collar portion.

This invention provides the means for construction crews to easily drill through multiple beams or soffits with the use of a hole saw that is coupled to a first drive cup using a coupling arbor. The first drive cup is attached to a first end of an extension tube and is secured using self-tapping screws. A second drive cup is attached to a second end of the extension tube with self-tapping screws where a drive coupling arbor provides a hexagonal shank that is attached to a drive device, such as a hammer drill or standard drill. When activated the rotational motion allows the hole saw to cut through the beams or soffits. A pilot bit is provided to guide the hole saw into the beams or soffits when in use.

The invention relates to a core drill with an end portion (3) and a drill bit portion (1-2). The end portion and the drill bit portion are joinable in a watertight fashion with a sealing element (11). The sealing element (11) is provided in a space between the end portion and the drill bit portion, such that it is being compressed in a sealing fashion when the end portion and the drill bit portion are joined. The end portion and the drill bit portion are locked together with a joining element (8, 10) which achieves this locking effect when moves in the radial direction of the core drill. When the joining element moves in this direction, the end portion and the drill bit portion move towards each other. Thus the sealing element is being compressed while concurrently the end portion and the drill bit portion are joined together. This is further achieved without the joining element having to extend in the axial direction of the core drill. Typically, the joining element (8, 10) is constituted by a set screw.

A device for holding and securing a tool, in particular, a drill bit, on a machine tool, for example, a core drill, including an output shaft for transmitting a torque generated in the machine tool to the tool; and a union nut positioned around the output shaft for detachably connecting the output shaft to an attachment end of the tool. The output shaft includes a locking ring and the union nut includes a washer disk, as well as an attenuator, the washer disk being positioned between the locking ring and the attenuator.

A drill bit is disclosed. The drill bit has a cutting portion having an annular portion, where the annular portion has a first end on which is disposed a cutting element and a second end that includes an outer insertion element and a stop shoulder. The drill bit has a drill shaft portion having a cylindrical drill shaft, where the drill shaft has an inner insertion element with an end face on a side of the drill shaft facing the cutting portion. The outer insertion element and the inner insertion element together form a plug connection in an insertion direction that is parallel to the axis of rotation and the insertion elements are connectable to each other via a pin element that is movable into a slot-shaped recess. The pin element is attached to an outside of the inner insertion element and the outer insertion element has the slot-shaped recess.

The present invention seeks to provide a simple, easily realisable and inexpensive solution to the problems discussed above. The present invention further seeks to provide a hole-saw device which enables rapid changes of hole saw. The present invention also seeks to provide a simple device for enlarging apertures which is simple, cost effective and can be used with standard drills of corded and battery types as well as manual types.

A hole cutter assembly is operable to cut a plurality of different sized diameter holes in a work piece. The hole cutter assembly includes an arbor configured to connect to a power tool for rotation about an axis, a drill bit coupled to the arbor for rotation with the arbor, a first arm moveable relative to the axis, a first cutting blade coupled to the first arm and moveable with the first arm, a second arm moveable relative to the axis, and a second cutting blade coupled to the second arm and moveable with the second arm. The first and second cutting blades are selectively moveable relative to the axis to adjust a cutting diameter of the hole cutter assembly. The drill bit engages the first and second arms to inhibit movement of the first and second cutting blades relative to the drill bit.

A cutting tool is provided that is operable to provide a circular cut or hole in a material or work piece. In various embodiments, a guide member is provided that facilitates alignment of a cutting edge of the invention with a pre-existing cut, hole or aperture. Devices and methods of the present disclosure provide for quick and easy centering of a cutting tool in order to form an enlarged hole that is concentric with a pre-existing hole.