| 摘要 |
In a double sliding sash window a latch (see also figure 2) is pivotally mounted in the parting bead groove 18 such that a catch 17 limits upward movement of the lower sash 12. The sash can only be raised, eg to be pivoted out of the frame for cleaning, when the upper sash 11 is lowered to contact cam 15 and pivot the latch to an inoperative position. In the embodiment of figures 7- 11 an extendable retaining bolt (33) enables the bottom sash to be pivoted out for cleaning without losing the tension in the spring counter balance. |
