knee type meaning in English

升降台型

Knee type vertical milling machines - testing of the accuracy
升降台型立式铣床.精度测试
Knee type horizontal milling machines - testing of the accuracy
升降台型卧式铣床.精度测试
Test code for performance and accuracy of numerically controlled knee type vertical milling machines
数控膝形立式铣床性能和加工精度试验规程
Machine tools ; behaviour of machine tools under static and thermal loading ; testing of vertical knee type milling machines
机床.静载荷和热载荷下的机床特性.垂直升降台式铣床
Machine tools ; behaviour of machine tools under static and thermal loading ; testing of horizontal knee type milling machines
机床.静载荷和热载荷下的机床特性.水平悬臂式铣床的