Method and apparatus for machining holes in crankshafts

An apparatus for machining holes in crankshafts at various angular positions about a longitudinal axis through the crankshaft and at various tilt angles to the rotational axis, comprising:

• a frame;
• a fixture on the frame having means for supporting a crankshaft for rotational positioning of the crankshaft about the crankshaft's longitudinal axis;
• means on the fixture for turning the crankshaft in a first, angular direction about the crankshaft's longitudinal axis while the crankshaft is supported in the fixture to present different peripheral surface sections of the crankshaft;
• a first machine head for carrying a tool, movable along three axes;
• the first axis being a vertical axis for positioning the tool vertically relative to the crankshaft;
• the second axis being a horizontal axis for positioning the tool horizontally relative to the crankshaft;
• the third axis being a horizontal plunging axis which is normal to the first and second axes, for presenting the tool to the crankshaft;
• and
• tilt means on the frame for tilting the fixture and the crankshaft carried thereon through a second angular rotation about a tilt axis and relative to the plunging axis to machine holes at various angles to the longitudinal axis and at various peripheral locations about the crankshaft.

An apparatus for machining holes in crankshafts at various angular positions about a longitudinal axis through the crankshaft and at various tilt angles to the rotational axis, comprising:

• a frame;
• a fixture having means for supporting a plurality of crankshafts for the synchronous rotational positioning of the crankshafts about the crankshafts' longitudinal axes;
• tilt means on the frame including trunnions mounting the fixture for tilting in an angular direction about a horizontal axis through a central portion of the fixture to present the crankshafts at various tilt angles to the plunging axis;
• means on the fixture for turning each of the crankshafts about their respective, longitudinal axes in a second angular direction while the crankshafts are supported in the fixture;
• a plurality of machine heads having tools, synchronously movable along three axes:
• the first axis being a vertical axis for positioning the tools vertically relative to the crankshafts;
• the second axis being a horizontal axis, parallel to the axis of the trunnions, for positioning the tools horizontally relative to the crankshafts;
• the third axis being a plunging axis, normal to the first and second axes, for presenting the tools to the crankshafts after the crankshafts have been rotatably positioned about both the axis of the trunnions and the crankshafts' longitudinal axes;
• means for storing a plurality of tools and tool support bushings, adjacent the machine heads for automatic transfer of different tools and tool support bushings to the machine heads;
• and
• means for positioning the tool support bushings in correct position between the plurality of crankshafts and tools.

An apparatus for machining holes in crankshafts at various angular positions about a longitudinal axis through the crankshaft and at various tilt angles to the rotational axis, comprising:

• a frame;
• a crankshaft workholder mounted on the frame for supporting a crankshaft for rotation about the crankshaft's longitudinal axis to present different angular positions for the machining of holes;
• a machine head mounted on the frame with a tool, movable along a plunging axis to present the tool to the crankshaft to machine holes therein;
• tilt means on the frame mounting the crankshaft workholder to tilt the crankshaft workholder at various angles to the plunging axis so that holes may be machined at various rotational positions about the crankshaft and at various tilt angles to its longitudinal axis;
• and
• an open face on one side of the crankshaft workholder to allow loading and unloading of a crankshaft when the workholder is tilted to a crankshaft loading position.

A method of machining crankshafts comprising the steps of:

• loading a crankshaft into a pivotable fixture;
• tilting the fixture about a first tilt axis relative to a tool-plunging axis;
• rotating the crankshaft in the fixture about the longitudinal axis of the crankshaft to align the hole location with the plunging axis;
• machining a first hole in the crankshaft;
• moving a tool head carrying a tool in three orthogonal directions relative to the crankshaft in the fixture to position the tool for machining another hole along the length of the crankshaft;
• machining a second hole in the crankshaft;
• and
• unloading the crankshaft with machined holes therein.

A method of machining crankshafts comprising the steps of:

• positioning a crankshaft fixture to have an open face facing upwardly to receive at least one crankshaft therein;
• loading at least one crankshaft into the fixture through the open face thereon;
• tilting the fixture to present the crankshaft to a tool and at a predetermined angle to the longitudinal axis of the crankshaft;
• rotating the crankshaft in the fixture to present a predetermined location on the crankshaft to be machined;
• plunging the tool into the workpiece to machine a hole at the predetermined location and at the predetermined angle, to the longitudinal axis of the crankshaft;
• removing the tool from the hole formed in the workpiece;
• and
• tilting the fixture to position the crankshaft for removal from the fixture.