Multiple pivoted lathe chuck jaw assembly

A multiple pivoted lathe chuck jaw assembly configured to be mounted on a lathe chuck, the lathe chuck having a central axis and a radially movable element that can be adjusted inwards and outwards from the central axis, the multiple pivoted lathe chuck jaw assembly comprising:

• a baseplate having a front face, a rear face, a left edge, and a right edge;
• a jaw assembly attachment on the rear face of the baseplate that attaches the baseplate to one of the radially moveable elements on the lathe chuck such that the baseplate is positioned perpendicular to the central axis of the lathe chuck and is radially movable inwards and outwards from the central axis in response to adjustment of the radially movable element;
• wherein, when the radially movable element is adjusted maximally inwards, the baseplate is at a minimum expansion point, when the radially movable element is adjusted maximally outwards, the baseplate is at a maximum expansion point, and when the radially movable element is adjusted midway between maximally inwards and maximally outwards, the baseplate is at a midway expansion point;
• a first pivoting attachment point on the front face and a second pivoting attachment point on the front face, the first and second pivoting attachment points are located along a pivoting attachment point arc defined by a pivoting attachment point radius measured from the central axis and extending from the left edge to the right edge;
• a first sub-jaw pivotably attached to the front face of the baseplate at the first pivoting attachment point and a second sub-jaw pivotably attached to the front face of the baseplate at the second pivoting attachment point;
• the first sub-jaw having a first tier and a second tier wherein the first tier is positioned above the front face of the baseplate and the second tier is positioned above the first tier;
• the first tier having a first tier compression gripping surface located along a first tier compression gripping surface arc defined by a first inner radius measured from the central axis, and a first tier expansion gripping surface located along a first tier expansion gripping surface arc defined by a first outer radius measured from the central axis;
• the second tier having a second tier compression gripping surface located along a second tier compression gripping surface arc defined by a second inner radius measured from the central axis, and a second tier expansion gripping surface located along a second tier expansion gripping surface arc defined by a second outer radius measured from the central axis;
• a plurality of force-directed serrations on at least one of:
• the first tier compression gripping surface, the first tier expansion gripping surface, the second tier compression gripping surface, and the second tier expansion gripping surface;
• the plurality of force-directed serrations each having a vertical extension tooth wall and an angled tooth wall;
• the vertical extension tooth wall extending outwards from the gripping surface, approximately parallel to the front face, and terminating at a serration point;
• the angled tooth wall extending outwards from the gripping surface at an angle of less than ninety degrees measured from the front face and also terminating at the serration point;
• wherein, when the baseplate is at the midway expansion point, the first inner radius matches a radius from the first tier compression gripping surface arc to the central axis such that a first workpiece being compressed by the first sub-jaw would have a workpiece radius that corresponds to the radius from the first tier compression gripping surface arc to the central axis, causing the first tier compression gripping surface to have maximum surface area contact with the first workpiece;
• wherein, when the baseplate is at the midway expansion point, the second outer radius matches a radius from the second tier expansion gripping surface arc to the central axis such that a second workpiece being expanded by the first sub-jaw would have a workpiece inner radius that corresponds to the radius from the second tier expansion gripping surface arc to the central axis, causing the second tier expansion gripping surface to have maximum surface area contact with the second workpiece;
• wherein, when the baseplate is at the maximum expansion point, the second inner radius matches a radius from the second tier compression gripping surface arc to the central axis such that a third workpiece being compressed by the first sub-jaw would have a workpiece radius that corresponds to the radius from the second tier compression gripping surface arc to the central axis, causing the second tier compression gripping surface to have maximum surface area contact with the third workpiece;
• and
• wherein, when the baseplate is at the maximum expansion point, the first outer radius matches a radius from the first tier expansion gripping surface arc to the central axis such that a fourth workpiece being expanded by the first sub-jaw would have a workpiece inner radius that corresponds to the radius from the first tier expansion gripping surface arc to the central axis, causing the first tier expansion gripping surface to have maximum surface area contact with the fourth workpiece.

A multiple pivoted lathe chuck jaw assembly configured to be mounted on a lathe chuck, the lathe chuck having a central axis and a radially movable element that can be adjusted inwards and outwards from the central axis, the multiple pivoted lathe chuck jaw assembly comprising:

• a baseplate having a front face, a rear face, a left edge, and a right edge;
• a jaw assembly attachment on the rear face of the baseplate that attaches the baseplate to one of the radially moveable elements on the lathe chuck such that the baseplate is positioned perpendicular to the central axis of the lathe chuck and is radially movable inwards and outwards from the central axis in response to adjustment of the radially movable element;
• wherein, when the radially movable element is adjusted maximally inwards, the baseplate is at a minimum expansion point, when the radially movable element is adjusted maximally outwards, the baseplate is at a maximum expansion point, and when the radially movable element is adjusted midway between maximally inwards and maximally outwards, the baseplate is at a midway expansion point;
• a first pivoting attachment point on the front face and a second pivoting attachment point on the front face, the first and second pivoting attachment points are located along a pivoting attachment point arc defined by a pivoting attachment point radius measured from the central axis and extending from the left edge to the right edge;
• a first sub-jaw pivotably attached to the front face of the baseplate at the first pivoting attachment point and a second sub-jaw pivotably attached to the front face of the baseplate at the second pivoting attachment point;
• the first sub-jaw having a first tier and a second tier wherein the first tier is positioned above the front face of the baseplate and the second tier is positioned above the first tier;
• the first tier having a first tier compression gripping surface located along a first tier compression gripping surface arc defined by a first inner radius measured from the central axis, and a first tier expansion gripping surface located along a first tier expansion gripping surface arc defined by a first outer radius measured from the central axis;
• the second tier having a second tier compression gripping surface located along a second tier compression gripping surface arc defined by a second inner radius measured from the central axis, and a second tier expansion gripping surface located along a second tier expansion gripping surface arc defined by a second outer radius measured from the central axis;
• a plurality of force-directed serrations on at least one of:
• the first tier compression gripping surface, the first tier expansion gripping surface, the second tier compression gripping surface, and the second tier expansion gripping surface;
• the plurality of force-directed serrations each having a vertical extension tooth wall and an angled tooth wall;
• the vertical extension tooth wall extending outwards from the gripping surface, approximately parallel to the front face, and terminating at a serration point;
• the angled tooth wall extending outwards from the gripping surface at an angle of less than ninety degrees measured from the front face and also terminating at the serration point;
• the first sub-jaw having a sub-jaw bottom surface located between the first tier compression gripping surface and the first tier expansion gripping surface and resting upon the front face of the baseplate;
• the first tier of the first sub-jaw having a first tier top surface located between the first tier compression gripping surface and the first tier expansion gripping surface and extending parallel with the first sub-jaw bottom surface;
• the first tier compression gripping surface and the first tier expansion gripping surface each are positioned at a dovetail taper to the front face such that a first angle measured between the front face and the first tier compression gripping surface is less than ninety degrees and a second angle measured between the front face and the first tier expansion gripping surface is less than ninety degrees;
• the second tier compression gripping surface and the second tier expansion gripping surface each are positioned at a dovetail taper to the first tier top surface such that a third angle measured between the first tier top surface and the second tier compression gripping surface is less than ninety degrees and a fourth angle measured between the first tier top surface and the second tier expansion gripping surface is less than ninety degrees;
• wherein, when the baseplate is at the midway expansion point, the first inner radius matches a radius from the first tier compression gripping surface arc to the central axis such that a first workpiece being compressed by the first sub-jaw would have a workpiece radius that corresponds to the radius from the first tier compression gripping surface arc to the central axis, causing the first tier compression gripping surface to have maximum surface area contact with the first workpiece;
• wherein, when the baseplate is at the midway expansion point, the second outer radius matches a radius from the second tier expansion gripping surface arc to the central axis such that a second workpiece being expanded by the first sub-jaw would have a workpiece inner radius that corresponds to the radius from the second tier expansion gripping surface arc to the central axis, causing the second tier expansion gripping surface to have maximum surface area contact with the second workpiece;
• wherein, when the baseplate is at the maximum expansion point, the second inner radius matches a radius from the second tier compression gripping surface arc to the central axis such that a third workpiece being compressed by the first sub-jaw would have a workpiece radius that corresponds to the radius from the second tier compression gripping surface arc to the central axis, causing the second tier compression gripping surface to have maximum surface area contact with the third workpiece;
• and
• wherein, when the baseplate is at the maximum expansion point, the first outer radius matches a radius from the first tier expansion gripping surface arc to the central axis such that a fourth workpiece being expanded by the first sub-jaw would have a workpiece inner radius that corresponds to the radius from the first tier expansion gripping surface arc to the central axis, causing the first tier expansion gripping surface to have maximum surface area contact with the fourth workpiece.