Fig. 24
For pivoting the door at the top, there is provided a top pivot and plate, as illustrated at (c). This pivot is applied to the edge of the door stile. Both the top pivot and bottom hinge plates on the door are offset.
Fig. 25
Double-acting floor hinges are rapidly displacing double-acting spring hinges. This is due to the fact that when the former hinges are employed the door is pivoted at the top and bottom and the weight of the door is not carried by the coils of the spring, as in the double-acting spring hinge. The floor type of double-acting hinge carries the weight of the door on a ball bearing in the box, or case, let into the floor, as shown at a, [Fig. 25], the coil performing only the function of closing the door. The hinge illustrated is not only a double-acting hinge, but is also a checking hinge, and for this reason is known as a double-acting, checking-spring hinge. In operating, this spring hinge not only closes the door, but prevents it, when closing, from oscillating after the door has reached its neutral, or closed, position.
There are numerous double-acting floor hinges in the market that are not of the checking type. Some of these are the Atlas and Simplex, made by Bardsley, the Bommer, made by Bommer Brothers, together with the Chicago, New Idea, Matchless, Chief, and Columbia, made by various manufacturers. All of these hinges embody practically the same principle, but differ somewhat in mechanism.
30. Outside Blind and Shutter Hinges.—The outside shutter, or blind, is still much used in the construction of dwelling houses, and a great variety of hardware is made to use in conjunction with hanging these devices. Only the most common of the many available types of this kind of hardware, however, will be treated here.