| 摘要 |
867,308. Window operating apparatus. WILMOT-BREEDEN Ltd. Sept. 7, 1959 [Sept. 8, 1958], No. 28719/58. Class 20(3) The weight of a vertically adjustable window 8 is counterbalanced by at least one pair of levers 4, 5, 4a, 5a pivoted together at one end 9, 9a and having their opposite ends connected respectively to a fixed part 6, 6a, and for engagement with the window 8, and a spring 10, or 10a, acting between the levers 4, 5 and between 4a, 5a such that the vertical component of the force exerted by the spring on the window is equal to the weight of the window together with the forces such as friction , opposing the motion of the window, and is large enought to prevent downward movement of the window against friction but not large enough to move the window vertically upwards against friction. As shown, the levers 5, 5a are pivoted to the window 8 by parts 7, 7a and the levers 4, 4a are pivoted to the fixed parts 6, 6a and the horizontal forces exerted on the window by the levers 5, 5a balance each other out. The invention may be applied to the electrically operated mechanism described in Specification 832,843. |
