Another patented revolving window that has been used to a considerable extent, is the Hey-debrand Safety Window. In this window the sash cord, chain or ribbon, instead of being attached directly to the sashes, is attached to a pivot, which is screwed to the centre of each sash. These pivots elide up and down in grooves in the pulley stile, carrying the sash with them, as in an ordinary window. In the lower half of the window the parting strip is omitted, and the outside casing is kept back of the face of the pulley stile. The lower half of the inside stop bead is hinged so that it can be swung in, thus permitting the lower sash to swing on its pivot. The upper sash can also be drawn down opposite the lower sash and then revolved in the same way, or the lower sash may first be pushed to the top of the window, and the upper sash drawn down, and then reversed, but neither sash can be revolved in the upper part of the frame. The action of the sashes requires a specially constructed frame, the details of which are shown in Fig. 107.

The pulley stile is made \\ inches thick, with a groove for the parting strip extending to the centre of the meeting rails, and 5/8 X -inch grooves for the pivots extending to within 1 inch of the sill, At the proper height a bearing is inserted in the pivot grooves for the pivots to turn on.

The stop bead is double rabbeted and is cut in two at M (detail B), the lower portion being hinged to swing in, as shown by dotted lines in detail A. 98. Casement Frames. - Windows in which the sash are hinged at the sides, to swing in or out like a door, are called easement windows. When the windows are 6 or 7 feet high and the sash are divided into two folds, the sill coming nearly to the floor, they are frequently termed French windows.

It is very difficult, and in fact almost impossible, to construct a casement window so that the rain cannot beat in, unless the sash are hung to swing out; and if the sash open outward it is impracticable to use outside fly screens. If the window is in an exposed position it will be much better to have the sash swing out, even if it does necessitate inside screens.

The construction of a casement window frame is very much like that of a door frame, the difference being in the arrangement of the wood sill and in the rebate for the sash.

97 Heydebrand Safety Window 20073

Fig. 107.

Fig. 108 represents a section through the jamb, sill and meeting stiles of a casement window in which the sash are to swing out, showing the English method of forming the rebates. In ordinary work in this country, the half-round rebate, B, is generally omitted, and also the astragal mould at A, the meeting stiles having an ordinary rebate. Fig. 110 shows a style of casement frame often used in the

Fig. 108.

97 Heydebrand Safety Window 20074

Fig. 109.

East. The rebate for the bottom of the sash is the same as in the previous example, but the side rebates are different. The hollow in the edge of the stop bead is made with the idea that if rain is driven through the rebates it will stop in this space and descend to the sill, where an outlet should be provided for it It should be noticed that with a frame of this pattern the sash can only open a little more than 900. If it is desired to swing the sash back against the wall, the edge of the frame must be kept out nearly to the face of the wall. The strip of board shown on the back inside edge of the frame is nailed to the frame for the purpose of holding it more securely in place, and may be in short lengths. The shape of the staff bead is purely a matter of design; often it is "stuck" on the frame, but there are some advantages in making it in a separate piece, as shown in the figure. The dotted lines across the transom bar show how it may be built of two pieces of plank.

Figs. 109 and 111 show two details for casement frames with the sash opening in. The former is the English method, and is generally considered the best, although the sill detail shown in Fig. 111 is an excellent one ; this joint is designed on the idea that if water penetrates to the groove, G, the force will be diminished by the increased area of the space, so that the water will collect in the bottom of the groove and pass out through little holes bored through the outer lip.

97 Heydebrand Safety Window 20075

Fig. 110.

97 Heydebrand Safety Window 20076

Fig. 111.

The outside finish of the frame shown in Fig. 111 is merely offered as a suggestion, and is not an essential part of the construction, the most important constructive features of these two details being the connections with the jambs and sill. Casement window frames and sash should always be at least 1 inches thick, and when in a brick or stone wall should be well secured to the masonry.

When casement windows are less than 5 feet high, and more than 3 feet wide, it is better construction to have a narrow mullion between the sash than to have the sash rebated together.