Self-centering arrangement for grinding the hardmetal pins of drill bits
AssigneeC.M.E. Blasting & Mining Equipment Ltd.
InventorsKallevi K. Manqvist, Robert Sjolander
Life of this patent
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Abstract
An arrangement for grinding the hardmetal pins of drill bits, e.g. the tungsten carbide buttons (31) of button bits (1), comprises means (parallel arms pairs 9 and 10) for adjusting the position of a grinding pin (15) in relation to the drill bit (1) and also journalling means (4) operative to cause the grinding machine (3) to move relatively slowly in a circuit path around the button on the drill bit (1) to be ground and to cause the grinding pin (15) to rotate rapidly around its longitudinal axis. The drill bit is clamped securely in a stationary holder arrangement (2) which includes a tiltable table (35) which can be adjusted to and locked in selected angular positions.
Claims9
A self-centering arrangement for grinding the hardmetal pins of drill bits of the kind used within the mining industry for drilling wells and like down-the-hole drilling operations, in which the drill bits (1) are clamped in a holder arrangement (2) including a liquid coolant collecting vessel (18) and which grinding arrangement includes a grinding machine (3) equipped with a grinding pin (15) driven by motor (23 to rotate about its longitudinal axis and further includes a grinding machine journalling device (4) which is positioned at an angle to the longitudinal axis of said grinding pin (15) and which is operative to allow the grinding machine (3) to move in an orbital path with the center of rotation lying in the grinding center of the grinding pin (15), characterized in that the grinding machine journalling device (4) is moveable in the horizontal and the vertical plane relative to the holder arrangement (2), which is stationary;
- and in that the journalling device is mounted on parallel arm pairs (5, 7) pivotally mounted on a vertical stand (6) said parallel arm pairs (5, 7) comprise an inner and an outer arm pair (9 and 10 respectively) which are pivotally connected together;
- in that the arm pairs (9, 10) coact with a piston-cylinder device (11, 12) acting on one pivot arm of said arm pair;
- in that the inner arm pair (9) is carried by the vertical stand (6) and the outer arm pair (10) is carried by the grinding machine journalling device (4);
- and in that the route of the supply pressure to the piston-cylinder-devices can be switched by means of a valve switch (14) to provide a vertically acting grinding pressure during an automatic grinding operation and to provide a compensating auxiliary pressure during normal manual movement of the grinding machine.
Dependencies are inferred from the claim text.