5x to admit screws to fit it. Its application to a sash is shown at d d. The groove may be cut in the side of the sash sufficiently deep for the whole to be buried when the spring is forced in, as the elasticity of the spring will project the roller sufficiently to steady the sash.
One of the principal objections to sliding sashes in shop windows, is the necessity in most cases of making a broad casing for the balance weights to pass up and down, which excludes the light, and so much space for the exhibition of goods, and is besides unsightly, according to the prevailing taste in these matters. To obviate these objections, sliding sashes have sometimes been made with a long train of pulleys and lines, to carry the weights to a distant situation, where there would be the least incumbrance. Mr. Lockart, of Poland-street, has however ingeniously contrived to place the weights in a horizontal position above the window, which is a very convenient situation, and the means adopted tor that purpose are calculated to work well. Fig. 1 in the annexed sketches represents an elevation, and Fig. 2 a plan, the correspondinglettters in each
Fig. 2 referring to similar parts, u is the upper sash closed; l the lower sash partly-opened; a the weight to the upper window; o the weight to the lower window; e e are the pulleys on which the lines run. The dark space above the window has been drawn too large in proportion to the other parts, but with the view of showing the arrangement more clearly. When the lower sash l is pulled down, the weight o is drawn close up under the pulleys, the curved pieces being cut out of the weights for that purpose. When the upper sash u is brought down, the weight a is drawn up close to the pulleys.
To arrange these several parts to act properly, it will be necessary to observe the depth of the casing above the window, where the weights are to move; if that be (for instance) the fourth part of the range of the sashes in their grooves, then the pulleys on which the lines that suspend the sashes are coiled, must be four times the diameter of their axes, that take up the lines from the weights. As by this arrangement, the weights only move through a fourth part of the space of the sashes in the same time (by the cords passing round pulleys showing these relative proportions,) it follows that the weights must be four times the weight of the sashes to balance them; and to save space, the weights should be of lead. By this arrangement it will be observed that there is only one case for the weights instead of two, and that the situation above the window is more convenient for repair than at the sides. For pastry-cooks, butchers, and market shops generally, this improvement offers great convenience and advantage.
Mr.Thomas Prosser, an architect of Worcester, patented, in 1830, "certain improvements in the construction of window-sashes, and in the mode of hanging the same," which appear to us deserving the attention of the reader. He proposes to attach the upper and lower sashes to the same lines which pa3s over a pulley attached to each side of the frame near the top of the window. These are of the kind usually called side pulleys, which have their axes at right angles to the surfaces to which they are attached. The small frames in which the pulleys turn are movable, in dovetailed grooves, in the window-frames, and adjustable by a screw to regulate the tension of the sash lines. The two sashes are thns made to balance each other, entirely obviating the necessity for the metallic counterpoises usually employed to. facilitate the raising and lowering of the sashes. From this description it will be perceived that one of the sashes cannot be moved without moving the other, so that the opening can never be made entirely at the top or bottom of the window, but an equal portion of it will be at each.
The method of attaching the lines to the sashes consists in tying neatly to the ends of the lines small pieces of metal, with longitudinal rectangular slits, which pass over T studs fixed into the sashes, with their heads across, by which the lines are secured from being accidentally detached when once they are hooked on. Instead of the beads which are generally fixed to the frame on each side of a window-sash, as guides to keep it in its place while stationary, and to preserve their perpendicular position while elevated or depressed, this patentee fixes a single rod into the frame, which fits accurately into a groove in the side of the sash. This constitutes a fitting less pervious to the weather than that usually adopted, at the same time that it affords great facility in cleaning the windows; for, as the guide-rod of the lower sash does not extend more than half-way down, so that the lower sash being elevated to the top of the window, escapes its guide-rod, and may be turned inside-out, and the upper sash being lowered to the bottom may be similarly reversed; so by this means all parts of the window can be brought within reach of a person in the room, for the purpose of cleaning or repairing.
We now proceed to describe a mode of securing house and shop windows from the depredations of robbers, which is applicable also to doors, gates, safes, etc, which was the subject of a patent granted to Messrs. Don and Smith, of Pentonville; and consists in the construction and adaptation of metallic shutters, arranged horizontally, in such manner that when the window or door is closed, each shutter forms a handsome panel; and when opened, they are entirely withdrawn, and deposited behind the entablature, or in the brickwork above or below the window. The patentees likewise claim the public patronage for another property possessed by their metallic shutters, - that of a ready conver sion into sun-blinds; but there will doubtless be many exceptions taken to the employment of so quick a conductor of heat, and of so ponderous a material as iron, for such a purpose. But whatever may be the substance used, the obviating of the necessity of sun-blinds as a separate appendage is worthy of consideration.