This is a suit in equity, brought for the infringement of certain reissued letters-patent, dated Oct. 11, 1875, for an improvement in sash locks. The original letters were issued to George Voll and George McGregor as joint inventors, and the reissue was granted to their assignee, the Hopkins & Dickinson Manufacturing Company, the appellant.
In the years 1868 and 1869 George Voll was the foreman of George McGregor, a locksmith of Cincinnati, who kept a shop where he sold sash locks. Prior to February, 1868, McGregor had been selling a self-locking sash lock made by Robert Lee, of Cincinnati, under letters granted to him dated May 30, 1865.
Sash locks are a contrivance which, by fastening the top rail of the lower sash to the bottom rail of the upper sash, prevent the opening of windows from the outside, either by lowering the upper or raising the lower sash. Their general construction and operation is as follows: A lever is pivoted upon the top rail of the lower sash. When the lock is open the directin of this lever is the same as the rail of the sash. To fasten the sashes it is necessary to turn this lever on its pivot to a position across and at right angles to the division line between the impinging rails of the two sashes, when it engages with a catch on the bottom rail of the upper sash. This catch, if, as has generally been the case, it consists of a simple hook, under the projection of which one end of the lever remains when in the locking position, is sufficient to prevent the opening of the window by any direct pressure on the sashes exerted in the ordinary way to open a window, but there would be nothing to prevent the pushing aside of the locking lever by inserting from the outside, between the impinging rails of the sashes, a knife-blade, paper-cutter, or other similar instrument, and thus opening the lock. To prevent this, various devices have been used to hold the locking lever fast when in the locking position, so that it could not be moved sideways from the outside, but only from the inside, by disengaging it from the catch in the ordinary process of unlocking.
This object was accomplished in the sash lock of Lee, by giving the lever a certain amount of play on its pivot, so that when it was turned to the locking position its end not only passed under the catch, but also behind a lip in the catch, thereby forming, with the latter, a latch which prevented any lateral movement of the lever. This was, therefore, called a self-locking sash lock. As in most sash locks, the pivoted locking lever was secured to a bed plate fastened upon the top of the upper rail of the lower and inner sash. This plate was designated the base plate. The catch was attached to a similar plate on the bottom rail of the upper sash, which was called the striking plate.
McGregor was unable to furnish the Lee sash lock to fill a large order which he had received, and mentioned the fact to Voll, who in a short time produced the model of a self-locking sash lock. In this lock the locking lever was pivoted on a cylindrical stump upon the base plate, the base plate being fastened upon the upper rail of the lower sash. There was a round hole in that part of the cylindrical stump nearest the inner edge of the sash rail, fitted to receive a small cylindrical pin or bolt. That part of the locking lever, which, when it was in the locking position, was over the rail of the inner sash, had a longitudinal hole extending through it to the pivotal stump. Through this hole a cylindrical pin extended from the outer end of the lever to the stump, and was pressed by a spiral spring against the stump. When the locking lever was turned around into the locking position, the end of the pin, by the action of the spring, entered the hole by a horizontal motion, and thus the lever was prevented from turning sidewise. When it was desired to unlock the lock, the pin, which projected beyond the end of the locking lever and ended in a knob, was pulled back out of the hole, and the lever was turned sideways into its unlocked position.
This sash lock was made about February, 1868, and on the 24th of that month Voll applied for letters for his invention, describing it as an improvement in sash locks, the object of which was to prevent the lock from being unfastened from the outside by inserting a knife or other thin instrument between the sashes, and pushing aside the locking lever. The claim was thus set forth in his specification: 'Having thus fully described and set forth the nature of my invention, what I desire to secure by letters is: The pin F, operating in hole in stump A, preventing the fastener from being turned, as described and set forth.'