| 摘要 |
A door 10 for closing off, for example, a brick kiln 11, is hinged at one edge for swinging movement on two hinges 14, 15 about a verticle hinge line and carries a jockey wheel 28 at the bottom of its opposite edge. When closed, the door rests on the ground and a pair of rams 25, 30 are provided for raising the door clear of the ground so that it may be swung open. One ram 25 is co-axial with the hinge line and the other 30 acts on the jockey wheel 28. The rams are operated by a manually- operated hydraulic pump 33. <IMAGE> |
