GB816055A - Improvements in or relating to safety catches for casement windows - Google Patents

Abstract

816,055. Turnbuttons. LINGWOOD, P. March 28, 1957 [Jan. 6, 1956], No. 533/56. Class 44 In a safety catch in which a latch is mounted on a window frame so as to rotate about an axis substantially at right angles to the general plane of the window and having a finger 17 which may be brought into engagement with a slot or groove on a lug or keep 18 on the surround 19 of the window opening which slot or groove has a first part 22 extending generally in a direction towards the general plane of the window opening and a second part 21 at the end of the first part nearest the window opening extending generally in a direction extending parallel to the axis of pivoting of the window and the other end of the first part of which slot or groove terminates in end faces 23, 24 extending on opposite sides of the slot or groove, the face on the opposite side of the first part of the slot or groove to the second part of the slot or groove is inclined inwardly towards the general plane of the window opening as the face extends away from the first part of the slot or groove. The latch is pivotally mounted on a lug 11 extending parallel with the general plane of the window and disposed inwardly of the glass. It is formed with a lever arm 14 projecting from a hub 13, the free end of the lever arm being cranked and constituting the finger 17. The latch also has a hand grip 15 on the opposite side of the hub 13 from the arm 14. The lug or keep 18 is of angle shape having a flange 20 which is secured to the surround 19 and the other part of which is provided with the slot or groove (shown as a slot). The corner 25 between the part 22 and the face 23 is arranged to extend further into the room than the corner 26 between the other side of the slot part 22 and the face 24. When the finger 17 is in engagement with the face 23 the window is drawn tightly against the surround 19 but if the latch is moved anticlockwise and the window is pushed in an opening direction the finger 17 will engage the corner 25 and move into the slot part 22. The window is then partly opened and if the finger is then moved into engagement with the slot part 21 the window is secured in the partly open position since the part 21 is not long enough to enable the finger to be withdrawn. The slot part 21 is of wedge shape to hold the finger 17 in the upper position. In a modification the slot can be curved instead of angle shaped. In a further modification suitable for use with windows having wooden window frames the lug or keep is a plate having slot parts 21, 22 as in the previous embodiment to enable the finger 17 to move and secure the window in the open position but also having a slot part 29 which extends both above and below the part 22 to provide the faces 23, 24 and so that in the upper part the window is secured in the closed position but by movement of the finger 17 into the lower part, the finger 17 can be swung clear of the lug or keep.