Hilti Aktiengesellschaft

Werner Bogner

Rolf Spangenberg

Paul Deutschenbaur

A method of manufacturing drilling crowns for cylindrical diamond drilling tool bits affords a waste-free fabrication of the drilling crowns impregnated with diamond particles. In a first step an annular axially extending middle or intermediate zone impregnated with diamond particles is joined at each of its opposite end by sintering to a different annular metal end zone. In a second step the intermediate zone is laser cut to form two similar drilling crowns with circumferentially spaced teeth. The teeth form diamond segments providing economical fabrication and a high quality connection with the end zones.

Method of manufacturing diamond-impregnated drilling crowns

A plug-in holder (2) of a drilling tool has an axially extending central bore for receiving a centering drilling bit. The holder (2) has an opening (5) extending from the bore to its outer surface. A latching element (6) is radially displaceably supported in the opening (5). The bore (4) has inwardly projecting entrainment ridges (9). The latching element (6) holds the centering drill bit in the axial direction while the entrainment ridges (9) engage the bit for rotational displacement.

Plug-in holder for centering drill bit

In drilling a bore in a structural component (3) using a hollow cylindrical core drill bit (4) initially a guide such as a disk (1) or a template (12) is secured to the surface of a structural component (3) for guiding one of the inner or outer circumferential periphery of the core drill bit. At the commencement of the drilling operation, the core drill bit (4) is guided by the disk or template and maintains the bit in a centered position. The guide can be fixed to the surface of the structural component (3) in a known manner, such as by an adhesive or by fastening elements (2, 6) driven directly into the structural component. Generally core drill bits of smaller diameter can be guided by the outer circumferential periphery of the guide (2) or by the inside circumferential periphery of the template (12).

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Munich, Germany

Werner Bogner