A two-hole core drilling machine of the invention includes a body, a vertically reciprocating carriage vertically reciprocably mounted to the body, a fixing plate coupled to one side surface of the carriage, to rotatably support a drive shaft of a motor, a pivoting plate fastened to the fixing plate under a condition that a pivot angle of the pivoting plate is changed, a moving plate fastened to the pivoting plate under a condition that a length of the moving plate from the pivoting plate is varied, a belt or chain mounted between a drive pulley coupled to the drive shaft and a driven pulley coupled to a driven shaft rotatably mounted to the moving plate, a first core bit coupled to the drive shaft, and a second core bit coupled to the driven shaft.

A diameter expansion drill bit used for inserting in a prepared hole perforated in a framework to expand a diameter of a portion of the prepared hole by grinding has a plurality of blade sections that grind the portion of the prepared hole, a blade holding section that holds the plurality of blade sections movably in a radial direction respectively, and a shank section that supports the blade holding section, and the plurality of blade sections move to spread outwardly in the radial direction with respect to the blade holding section by centrifugal force due to rotation.

To provide a method for forming an anchor hole and a diameter expansion device by which a centrifugal force can be appropriately adjusted when a cutting-blade portion is moved in a radial direction by the centrifugal force to grind a diameter expansion portion. In a method for forming an anchor hole for a post-installed anchor in which a diameter expansion drill bit is inserted and rotated in a prepared-hole portion bored in a concrete fixing body and a cutting-blade portion of the diameter expansion drill bit is moved in a radial direction by a centrifugal force to grind a part of the prepared-hole portion to form a diameter expansion portion, the minimum value of the centrifugal force applied to grind the diameter expansion portion is 0.75 N and preferably 1.1 N.

A lifting device for brittle elements such as bridge beam and deck elements, panels and the like up to and beyond 1,000 tonnes is described. The lifting device may be suitable for face and edge lifting of brittle elements that have a suitable cavity formed within or through them. The lifting device may include a lifting eye connected to an elongate member/shank that has a flared end. A sleeve about the shank may be used to raise and lower the moveably attached wedges to and from the flared end. In use the wedges upon the flared end prevent the withdrawal of the lifting device from the cavity of the brittle element. A cavity former is also described that may be used in the casting of the brittle element to form a suitable cavity.

A drill bit includes a pointed head and a bit shaft. A dust suction passage is formed in the bit shaft. A hole with an opening is formed in the pointed head or in a portion of the bit shaft, the portion being near a distal end of the bit shaft. The bit shaft includes a first portion, the first portion including a core and a rib. The core extends in an axial direction, and is thinner than the pointed head. The rib protrudes radially outward from a side surface of the core, and extends over an entire length of the first portion. The dust suction passage extends through the core in the axial direction.

An application tool, in particular a chisel or a drill bit, is disclosed. The application tool has a tool head. The application tool further has a shank region in which a main body is arranged, wherein the main body has a first hardness. The application tool further has a coating that has a second hardness greater than the first hardness. The coating includes a hard metal, which comprises a hard material and a metal matrix. Advantageously, the durability of the application tool can be increased as a result.

Systems and methods for creating a weep hole in an uncured, concrete, hollow core structural component having one or more external surfaces and one or more internal surfaces. The weep hole is drilled using a drilling apparatus comprising a drill, a rotating drill bit with an internal fluid passageway, a power source, and a pressurized fluid source. Loose, uncured concrete material deposited near the weep hole on the one or more internal surface as a result of drilling the weep hole is removed by releasing pressurized fluid which flows from the pressurized fluid source, through the drill and the rotating drill bit.

Systems and methods for creating a weep hole in an uncured, concrete, hollow core structural component having one or more external surfaces and one or more internal surfaces. The weep hole is drilled using a drilling apparatus comprising a drill, a rotating drill bit with an internal fluid passageway, a power source, and a pressurized fluid source. Loose, uncured concrete material deposited near the weep hole on the one or more internal surface as a result of drilling the weep hole is removed by releasing pressurized fluid which flows from the pressurized fluid source, through the drill and the rotating drill bit.

A one-piece cutting head for a drill bit includes a main cutting edge that extends between radial extremities of the cutting head. The main cutting edge is disposed between main rake surfaces and main relief surfaces. Each main rake surface includes one or more rake facets, and each main relief surface includes one or more relief facets. Adjacent rake facets and relief facets define a primary transverse edge therebetween that extends away from the main cutting edge. The cutting head further includes a plurality of side cutters that are transverse to the main cutting edge and that propagate from the primary transverse edge to a radial extremity of the cutting head. Each side cutter includes a side cutting edge between a side cutting rake facet and a side cutting relief facet.

A masonry drill head is made from a sintered cemented carbide. The masonry drill head has an at least section-wise planar joining end for heat induced joining to a shaft, a working end for shattering masonry material under a percussive motion, at least two conveying webs each emerging from the joining end and at least two conveying grooves each extending between two of the conveying webs. A cross-sectional solid material area of the masonry drill head increases towards the joining end, such that a masonry material debris intake of at least one of the conveying grooves increases towards the working end.