Method to create and utilise a virtual spring to create an energy neutral adjustment of a zero stiffness mechanism

摘要

A balance support device incorporating a virtual adjusting zero-free length spring within a gravity-equalised structure is provided. The device comprises a semi-circular outer support frame 4 which includes a semi-circular guide-rail. Within the semi-circular guide-rail run the long ends of a pantograph 6 which has a central pivot point 12 located on a vertical guide-rail 5. The adjustment of the pantograph 6 is maintained by a combination of movable guide blocks 13 and fixing means 9 for screwing the guide blocks into the vertical guide-rail 5. Two springs 3 have each of their ends attached to a long end of the pantograph 6 and to a horizontally extending parallelogram arrangement 7. The two springs serve to balance any load applied to a distal end of the parallelogram arrangement 7. The springs can thus be adjusted via a conical-path within the Y-Z-axes to create a resultant centre-line virtual spring force whose spring-length can be altered as is its effective attachment point on the Y axis.