Abstract: An abrasive grinding wheel having an inclined edge is obtained by subjecting an abrasive disc composed of spring steel sheet, preferably after flat grinding of the abrasive face, to stamping or turning followed by flat grinding. A grinding wheel of this type allows the capacity of a cutting off, smoothing, edge planing and polishing machine with automatic charging to be increased considerably.

Abstract: The invention relates to a device for closing, without a surge, one end of a core barrel installed in a mining or oil drilling rig, optionally equipped with a turbine.This device comprises a tubular element in whose bore there is guided a sliding member which provides a passage for the drilling liquid under pressure, this sliding member being movable in the above-mentioned bore under the influence of a variation in the flow of drilling liquid between a first position in which it keeps a closing member such as a ball remote from a seat provided at the above-mentioned end of the core barrel and, when it has engaged in the second section of the bore allows the closing element to be held in the first section of the bore, and a second position in which it allows the closing element to pass from the first section of the bore into the second section thereof and to place itself on the seat of the core barrel when the sliding member returns to its starting position.

Abstract: There is provided a surface-dressing tool for petrous materials exhibiting a better bite for a lower sound level and a lower energy consumption in that it comprises a pair of cylindrical surface-dressing rollers mounted rigidly on the ends of axles extending parallel between them. The driving force on a pair of rollers on one and the same axle is the resultant of the friction components of opposite sign of each roller in relation to the working surface.

Abstract: A higher performance, lighter and thinner composite sawing disc for stony materials is made by assembling, preferably by bonding, a peripheral rim (2) provided with diamond segments (6) on a self-supporting, metallic honeycomb structure (3) strengthened at its center by a central ring (4). Excellent strength of the assembly is obtained by bonding annular discs (5) of thin plate to the lateral faces.

Abstract: A well bore enlarger comprising, in its fixed-arm embodiment, a tubular housing member having an enlarged section with an outer diameter substantially the same as the well bore diameter, the enlarged section having a plurality of longitudinal cut-out portions defining blades of the enlarged section therebetween; a longitudinal slot within the blade; a cutting arm mounted to the blade within the slot having cutting edges and a fluid gallery between the cutting edges which gallery communicates with the slot and the well bore; synthetic diamond material attached to the cutting arm; and means on the tubular housing member for directing a fluid through the fluid gallery of the cutting arm. In the expandable-arm embodiment of the well bore enlarger, the tubular housing member is formed with the enlarged section as previously described, with slots, blades and cut-out portions.