Hammer R
Department of Orthopedics, University Hospital, Linköping, Sweden.
Acta Orthop Scand. 1988 Dec;59(6):708-11. doi: 10.3109/17453678809149431.
Using a ball-and-socket joint model, the optimal mechanical design of a simple universal ball joint was established. The maximum resistive moment was 70-72 Nm for a tightening torque moment of 5 Nm, their ratio being 14. The corresponding ratios for the Hoffmann universal ball joint and Orthofix are 1.0-4.3 and 1.1-1.6, respectively. A complete unilateral frame consists of two ball joints and one square connecting tube. Full-frame behavior under external loads was tested in the three principal planes and in torsion. Compared with a Hoffman quadrilateral system, the new system was four times more rigid in the anteroposterior plane, similar in axial load and lateral bending, and 64 percent more rigid in torsion.
使用球窝关节模型，建立了一种简单通用球窝关节的最佳机械设计。对于5 Nm的拧紧扭矩，最大阻力矩为70 - 72 Nm，其比值为14。霍夫曼通用球窝关节和奥托菲克斯的相应比值分别为1.0 - 4.3和1.1 - 1.6。一个完整的单侧框架由两个球窝关节和一个方形连接管组成。在三个主平面和扭转情况下测试了外部载荷下的全框架性能。与霍夫曼四边形系统相比，新系统在前后平面的刚度高四倍，在轴向载荷和横向弯曲方面相似，在扭转方面刚度高64%。
