Female part and a method for manufacturing female parts
AssigneeSandvik Intellectual Property AB
InventorsPeter Nava, Peter Sörensen
Life of this patent
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Abstract
The present invention A relates to a female part intended for top hammer-drilling equipment and a method for manufacturing female parts. The female part has a thread in the form of a ridge (2) in a wall (5). The ridge is delimited by a crest (9) and two flanks (10) between which a likewise helical groove (11) having a bottom (12) runs. An end the of the groove (11) is defined by a borderline (18), which separates the groove bottom (12) from a part surface (19) formed in the inside of the wall (5), the width of which part surface successively decreases in the peripheral direction, and which has a rotationally symmetrical shape essentially similar to the rotationally symmetrical basic shape of the thread (1).
Claims8
A female part for top hammer-drilling equipment, comprising a hollow space defined by a centre axis, which hollow space mouths in a free end of the female part and is delimited by a surrounding wall and by a stop shoulder axially spaced from the free end, a female thread formed on the inside of the wall in the shape of a ridge, which has a rotationally symmetrical, cylindrical or conical basic shape and extends helically along the inside of the wall, said ridge being concentric with the centre axis of the hollow space, and being delimited by a crest and two flanks between which a likewise helical groove runs, said groove having a bottom, said thread having full profile along a main section of a certain axial length, and comprising an end positioned between the full profile section and the stop shoulder and in which the groove runs out, wherein the depth of the groove successively diminishes towards said end, said end being defined by a borderline, which separates the groove bottom from a part surface formed in the inside of the wall, said part surface having the same rotationally symmetrical shape as the thread by extending along an imaginary cylinder or imaginary cone coinciding with either the crest of the thread or its groove bottom.
Female part according to claim, wherein the imaginary cylinder or cone also coincides with the entire part surface.
A method for manufacturing a female part intended for top hammer-drilling equipment and of the type that comprises a hollow space mouthing in a free end of the female part and being delimited by a surrounding wall having a female thread that has a rotationally symmetrical basic shape, and a stop shoulder spaced from the free end, said thread having a full profile along a main section of a certain length, and comprises two shorter end sections in which the groove of the thread runs out, comprising the steps of bringing a hollow work piece to rotate around a centre axis, bringing a turning tool into the hollow space of the work piece, longitudinally feeding the turning tool between the opposite end regions of the hollow space and simultaneously transversally feeding the same radially in order to generate the desired thread profile, wherein the further steps of, during continuous longitudinal feed in one and the same pass, bringing the tool to alternatingly move between radially outer and inner end positions, the outer one of which generates the groove bottom of the full-profile thread and the inner one generates the thread crest thereof, and during a concluding operation successively reducing the radius difference between the two radial end positions to zero in order to terminate the thread groove with a successively diminishing depth up to an end in the shape of a borderline which separates the groove bottom from a part surface formed in the inside of the wall, said part surface having the same rotationally symmetrical shape as the thread by extending along an imaginary cylinder or imaginary cone coinciding with either the crest of the thread or its groove bottom.
Dependencies are inferred from the claim text.