Multi-spindle drilling machine

In a multi-spindle drilling machine, comprising:

• a frame;
• base slide means linearly slidably supported on said frame for movement in a selected horizontal direction;
• drive means connected to said base slide means for causing selective slidable displacement thereof in said horizontal direction;
• a rotatable index plate supported on said slide means for rotation about a vertical axis, said index plate having an upwardly facing support surface adapted to have a workpiece mounted thereon;
• head means spaced upwardly above said index plate and vertically slidably supported on said frame, said head means having support plate means defining a horizontal centerline which is parallel to said horizontal direction and intersects said vertical axis;
• a pair of first tool spindles rotatably supported on said plate means and projecting toward said index plate, said first spindles defining a first reference line which extends horizontally between and intersects the rotational axes of said first spindles, said first reference line being perpendicular to said horizontal centerline;
• first means movably supporting said first spindles on said plate means so that said first spindles are symmetrically supported on opposite sides of a vertical reference plane which passes through said horizontal centerline;
• first means for selectively adjusting said first supporting means for causing said first spindles to be simultaneously and synchronously moved in opposite directions along said first reference line selectively toward or away from said vertical reference plane;
• a pair of second tool spindles rotatably supported on said plate means and projecting toward said index plate, said second spindles defining a second reference line which extends horizontally between and intersects the rotational axes of said second spindles, said second reference line being parallel to and spaced from said first reference line;
• second means movably supporting said second spindles on said plate means so that said second spindles are symmetrically disposed on opposite sides of said vertical reference plane;
• second means for selectively adjusting said second supporting means for causing said second spindles to be simultaneously and synchronously moved on opposite sides of said vertical reference plane, said second adjusting means including (1) a first adjusting device for causing said second spindles to be simultaneously and synchronously moved in opposite directions along said second reference line selectively toward or away from said vertical reference plane and (2) a second adjusting device for causing both of said second spindles to be simultaneously and synchronously moved selectively toward or away from said first reference line, said first and second adjusting devices being independently controllable for selecting the desired movement and the resulting locations of said second spindles;
• whereby said first adjusting means and said first and second adjusting devices can be individually selectively adjusted so as to selectively position the four spindles at uniformly spaced intervals on a pitch circle of selected diameter, with said base slide means being selectively slidably displaced along said horizontal direction until the vertical axis of rotation of said index plate is vertically aligned with the center of said pitch circle, thereby permitting simultaneous drilling or tapping of at least four holes in a workpiece with said holes being uniformly spaced apart and located on the pitch circle of selected diameter.