| 摘要 |
A shield type support for use in underground mining comprises a floor construction with one or more pressure operated extensible and retractable rams mounted on the floor and connected at their upper end to a roof-member. The roof-member is articulated at one end to a breaking shield which has an opposite end which is supported by lemniscate guide rods. The lemniscate guide rods are carried on a support which is mounted for adjustable movement on a column supported on the floor. In addition, this support also advantageously carries an additional adjusting element in the form of a telescopically retractable and extensible ram connected between the support and the roof structure at a spaced location from the other rams. |
