Parallel link machine design

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated drive sphere, said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated drive spheres,
• each said bifurcated drive sphere being retained within a complimentary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retained bifurcated drive sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis,
• wherein said bifurcated drive spheres each comprise two hemispheres, one for each strut passing through the respective bifurcated drive spheres, the two hemispheres being spherically arranged with respect to each other so as to be pivotable relative to each other about a common axis, and the spherically arranged hemispheres being retained in said complementary sockets providing for multi-axis movement thereof,
• wherein each of said hemispheres comprises a strut drive motor,
• wherein the strut drive motor is adapted to drive the respective strut through the respective hemisphere by means of a friction drive,
• wherein said friction drive comprises opposite pairs of driven rollers frictionally engaging opposite sides of the respective strut
• wherein said rollers are each coupled to larger diameter wheels which span the strut width and mutually contact each other in respective pairs, at least one such pair being driving by a pinion which is driven by the motor.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated drive sphere, said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated drive spheres,
• each said bifurcated drive sphere being retained within a complimentary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retained bifurcated drive sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis,
• wherein said bifurcated drive spheres each comprise two hemispheres, one for each strut passing through the respective bifurcated drive sphere, the two hemispheres being spherically arranged with respect to each other so as to be pivotable relative to each other about a common axis, and the spherically arranged hemispheres being retained in said complementary sockets providing for multi-axis movement thereof,
• wherein the three bifurcated drive spheres are supported in a generally vertical plane,
• wherein the three bifurcated drive spheres are supported in a generally vertical plane by means of a cast or molded body which has a generally horizontally extending point defining a support for a horizontal worktable, and including a removable cover defining a wholly enclosed workspace with said cast or molded body.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, said hexapod structure comprising six elongate struts defining with a sub-frame and a platform movable relative thereto and six nodes, three of said six nodes connecting alternate strut pair ends to the platform by multi-axis couplings and another three of said six nodes defined in said sub-frame comprising bifurcated drive spheres,

• each said bifurcated drive sphere being retained within a complimentary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retained bifurcated drive sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis, two of said struts being movably connected together at one end so as to define a first tool support movable in space in dependence upon the lengths of said two struts, and a further two of said struts being movably connected together at one end to define a second tool support movable in space in dependence upon the lengths of said two struts, and a tool supported between said first and second tool supports,
• each said bifurcated drive sphere further comprising two separate hemispheres, said two separate hemispheres each containing at least one strut driving mechanism, and wherein said two separate hemispheres are retained within a single complimentary socket mounted on said sub-frame, providing for multi-axis movement of said hemispheres, and
• wherein said two hemispheres are spherically arranged with face-to-face base planes so as to be rotatable relative to each other about a common axis perpendicular to the base plane of each hemisphere.

A machine comprising a hexapod structure, said hexapod structure comprising six elongate struts defining with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings, and three of said nodes defined in said sub-frame comprising bifurcated drive spheres,

• each said bifurcated drive sphere being retained within a complimentary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retaining sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis, two of said struts being adjustable length struts spaced apart and journalled for multi-directional pivotal movement relative to said machine sub-frame at one end and movably connected together at their other ends so as to define a first tool support movable in free space in dependence upon the relative lengths of the two struts,
• each said bifurcated drive sphere further comprising two separate hemispheres, said two separate hemispheres each containing at least one strut driving mechanism, and wherein said two separate hemispheres are retained within said complementary socket mounted on said sub-frame, providing for multi-axis movement of said hemispheres,
• wherein said two separate hemispheres are spherically arranged with face-to-face base planes so as to be rotatable relative to each other about a common axis perpendicular to the base plane of each hemisphere and
• wherein a second tool support movable in free space is defined by the movably connected ends of two further adjustable length struts which at their other ends are spaced apart and journalled for multi-directional pivotal movement relative to said sub-frame.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated drive sphere said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated drive spheres,
• each said bifurcated drive sphere being retained within a complimentary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retained bifurcated sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis, a friction drive motor for effecting relative longitudinal movement between the motor and an elongate strut, said friction drive motor comprising opposite pairs of driven rollers frictionally engaging opposite sides of the elongate strut, said opposed pairs of driven rollers being coupled to larger diameter wheels which frictionally engage with each other across the width of said elongate member,
• each said bifurcated drive sphere further comprising two separate hemispheres, said two separate hemispheres each containing at least one strut driving mechanism, and wherein said two separate hemispheres are retained within a single complimentary socket mounted on said sub-frame, providing for multi-axis movement of said hemispheres, and
• wherein the said two hemispheres are spherically arranged with face-to-face base planes so as to be rotatable relative to each other about a common axis perpendicular to the base plane of each hemisphere.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated common node said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated common nodes retaining adjacent strut pairs such that the struts can pass through said bifurcated common node and cross over each other with pivotal movement about a common axis;
• said bifurcated common nodes each comprise two hemispheres comprising a strut drive motor, one for each strut passing through the respective bifurcated common node, the two hemispheres being spherically arranged with respect to each other so as to be pivotal relative to each other about a common axis, and spherical arrangement being retained in a complimentary socket providing for multi axis movement thereof;
• said strut motor driving the respective strut through the respective hemispheres by means of a friction drive, said friction drive having opposite pairs of driven rollers frictionally engaging opposite sides of the respective strut;
• said rollers being coupled to larger diameter wheels which span the strut width and mutually contact each other in respective pairs, at least one such pair being driven by opinion which is driven by the motor.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated common node said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated common nodes retaining adjacent strut pairs such that the struts can pass through said bifurcated common node and cross over each other with pivotal movement about a common axis;
• said bifurcated common nodes each comprise two hemispheres comprising a strut drive motor, one for each strut passing through the respective bifurcated common node, the two hemispheres being spherically arranged with respect to each other so as to be pivotal relative to each other about a common axis, and spherical arrangement being retained in a complimentary socket providing for multi axis movement thereof;
• said strut motor driving the respective strut through the respective hemispheres by means of a friction drive, said friction drive having opposite pairs of driven rollers frictionally engaging opposite sides of the respective strut;
• said rollers being coupled to larger diameter wheels which span the strut width and mutually contact each other in respective pairs, at least one such pair being driven by a pinion which is driven by the motor, wherein said struts comprise elastomeric saddles on opposite sides thereof which each retain an elongate flexible rod to be contacted by said friction drive.

A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and

• wherein at least two struts share a bifurcated common node said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said nodes defined in said sub-frame comprising bifurcated common nodes retaining adjacent strut pairs such that the struts can pass through said bifurcated common node and cross over each other with pivotal movement about a common axis;
• said bifurcated common nodes each comprise two hemispheres comprising a strut drive motor, one for each strut passing through the respective bifurcated common node, the two hemispheres being spherically arranged with respect to each other so as to be pivotal relative to each other about a common axis, and spherical arrangement being retained in a complimentary socket providing for multi axis movement thereof;
• said strut motor driving the respective strut through the respective hemispheres by means of a friction drive, said friction drive having opposite pairs of driven rollers frictionally engaging opposite sides of the respective strut;
• said rollers being coupled to larger diameter wheels which span the strut width and mutually contact each other in respective pairs, at least one such pair being driven by a pinion which is driven by the motor, wherein the three bifurcated common nodes are supported in a generally vertical plane, the three bifurcated common nodes are supported in a generally vertical plane by means of a cast or molded body which has a generally horizontally extending point defining a support for horizontal work table and a removable cover defining a wholly enclosed workspace within said cast or molded body.