| 摘要 |
An access tower 1 comprises two end frames 2, each including a pair of stiles 4 connected by a plurality of rungs 5 spaced apart from one another with a predetermined pitch, The tower includes at least one advanced guard rail 12 provided between the two end frames 2. The rail 12 is a frame made from frame members 13, 14, 15, 16, 17. A hook (18A, 18B, 18C, 18D Fig 2) is provided at each respective corner of the frame, and each hook is configured to receive a rung 5 of a respective end frame 2 therein. The advanced guard rail is characterised in that the distance between the centre of an upper hook (18A, 18B, Fig 2) and the centre of a corresponding lower hook (18C, 18D, Fig 2) is intentionally less than the distance between the centre of the rungs of the end frame with which the hooks engage. Preferably, a locking mechanism features on the lower hooks as shown in Figure 4 which includes lever 21 and locking clamp 22 which enables the hooks (18C, 18D) to lock the rail against an end frame over a variable position. |
