| 摘要 |
785,063. Mine roof supports. BRAND, J. April 7, 1955, No. 10239/55. Class 20(2) In a lagging iron connection consisting of interengaging tongue and fork portions b, d respectively connected by a pivot pin e and clamped by a wedge h the lagging iron a previously fixed has its tongue b pointing towards the coal face and the distance between the axis of the pivot pin e and the free end of the fork d is not greater than half the height of the lagging iron crosssection. The end face k of the tongue b is slightly concave and the wedge h is guided in a heart-shaped recess i so that the wedge can be inerted in two different oblique positions and can be moved from one position to the other without being completely detached from the lock. |
