US298787A - Pneumatic door-check - Google Patents

Description

(No Model.)

J. A. SHERMAN.

V PNEUMATIC DOOR GHEGK. No. 298,787. Patented May 20, 18 84.

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JOHN A. SHERMAN, OF BOSTON, MASSACHUSETTS.

PNEUMATIC DOOR CHECK.

PECIFICATION forming part of Letters Patent No. 298,787, dated May 20, 1884. Application filed August 13, 1883. (No model.)

To aZZ whom, it may concern Be it known that I, JOHN A. SHERMAN, of Boston, county of Suffolk, and State of Massachusetts, have invented an Improvement in Automatic Door-Ohecks, of which the following description, in connection with the accompanying drawing, is a specification, like letters on the drawing representing like parts.

My invention relates to a door-check of that class in which a cylinder is employed in connection with a piston and actuating-spring, the said piston and cylinder being connected with the door and door-frame in such manner that the force of the spring acting on the piston tends to close the door, and the movement of the parts is checked or cushioned by air trapped between the piston and cylinder, to thus prevent the door from slamming.

The present invention consists, mainly, in a novel construction and arrangement of the -connecting mechanism between the said piston and cylinder and the door and its frame, as will be hereinafter described.

The drawing represents in plan view a door, and in section a portion of its frame, provided with a door-cheek embodying this invention, the parts being shown in full lines in the position assumed when the door is closed, and in dotted lines in the position assumed when the door is partially opened.

The cylinder a and the piston I) and actuating-sprin g 0, (shown in dotted lines,) and the valve or device in the cylinder-head d, for controlling the escape of air from between the said piston and cylinder-head, are all substantiallythe same as in door-checks heretofore in use, and consequently do not need any detailed description.

The cylinder-head (Z is provided with a lug, at, extending along the side of the cylinder a short distance from the end thereof, and pivoted upon a pivot-plate, 6, adapted to be rigidly fastened upon the door or its frame, and the piston-rodf has an extension, 1'', forming an integral part thereof, which is turned back at the side of the cylinder and pivotedat it upon the said pivot-plate c, a short distance from the pivotal point (1 of the cylinder, so that when the said cylinder and piston-rod are turned on their pivot-points d and h in the direction of the arrow 2 the piston-rod f will be moved away from the cylinder-head d,

compressing the actuating-spring c, which is interposed between the piston and the oppo site cylinder-head. The cylinder and pistonrod are caused thus to turn on their pivotal points to compress the spring 0 when the door is opened by means of aconnecting-bar, i, pivoted to the piston-rod f at m and to the doorframe at a, if the pivot-plate c is attached to the door 5 but if the pivot-plate were attached to the door-frame the connecting-bar t would be pivoted. to the door.

It will be seen that the hinge or axis of movement of the door and the pivotplate e and connecting-bart' are in such position with relation to one another that as the door is turned on its hinge the cylinder and piston-rod are rocked on their pivot-points d and h, and the piston Z) is thus moved through the cylinder. In this movement air is introduced between the piston and cylinder-head d, in the usual manner, and the actuating-spring c is compressed, so that as soon as the door is released by the person who openedg it the said spring will tend to force the piston back through the cylinder, thus restoring the parts to their normal position (shown in full lines) and closing the door, the air contained between the piston and cylinder-head d checking and cushioning this movement so as to prevent the door from slamming, in the usual manner.

Door-checks have been made previous to my invention in which the cylinder is pivoted at one side of its extreme end upon a pivotplate at substantially the same distance from the door as the pivotal point of the cylinder. By pivoting the cylinder at a short distance from its end, as herein shown-or, in other words, by making the pivotal point of the cylinder at a greater distance from the door than that of the extension of the piston-rod a greater throw of the piston in the cylinder is produced, and the piston-rod is caused to travel more freely through the cylinder-head, thus reducing the wear of these parts;

By making the piston-rod and its extension of a single piece, as herein described, the construction of the apparatus is simplified and its cost reduced without detriment to the op eration.

The distance from the pivot-plate of the pivotal point (1 of the cylinder beyond the pivotal. point it of the piston-rod extension is between the piston-rod and its extension.

I claim- The cylinder and piston and piston-rod provided with an extension combined with the pivot-plate to which the said cylinder and rodextension are pivoted, the pivotal point of the cylinder being farther from the plate than that of the rod-extension by a distance about equal to that between the said pivots measured parallel with the plate, substantially as and for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN A. SHERMAN.

Vitnesses:

J os. P. LIVERMORE, W. H. SIGsToN.

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