The opinion of the court was delivered by: ABRUZZO
Letters Patent No. 1,914,237 were granted on June 13, 1933, to the plaintiff as assignee of Robert L. Blanchard. This suit is brought by the plaintiff against the defendant for infringement of these letters patent.
The invention described and claimed in the patent relates to a wing-locking mechanism for use with a panic proof type of collapsible revolving door. This type of door is one in which the four door wings are supported from a central supporting column so that they are normally disposed in radial position. When this door is operated normally, the four door wings with its supporting column rotate as a unit with the doors in radial position. In the event of a panic, if abnormal pressure is applied to opposing door wings they both collapse and fold, leaving room for persons egressing from the building to pass through the entrance way without interference.
It is claimed by the plaintiff that previous to the present invention door wings were held in radial position by using cables, chains or braces connected between adjacent wings. The adjacent door wings were held in predetermined spaced relationship with respect to each other by means of cables, chains or braces. To release the doorway under this type of mechanism when excessive pressure was applied to opposing door wings, one end of each cable, chain or brace was held in a clamp that was released when this excessive pressure was applied to opposing door wings.
There were many disadvantages pertinent to this type of doorway and they proved unsatisfactory. They may be summarized as follows:
I. In the old type of door the door wings were tied to each other rather than to the central support with the result that release of one door wing released them all. This made it extremely difficult to manage the door wings while the door was being manually collapsed.
II. Since the door wings were tied to each other rather than firmly tied to the central supporting column or shaft, it was possible for the door wings to shift from their radial position while still maintaining their 90-degree relationship between themselves. The result of this was to foreshorten the distance between the edge of the door wings and the supporting column and break the air seal between the edge of the door wings and the revolving door enclosure. Naturally this was undesirable because a revolving door is primarily a closure and if a proper air seal was not formed cold air would be permitted to enter the building.
III. The cables, chains or braces obstructed the space between the door wings and in that way interfered with people, especially when they were carrying parcels or bundles, who were passing through the entrance way. Also after the cables or chains began to fray they would sometimes catch on the clothing of people, causing damage.
IV. It was difficult to obtain exact adjustment. It will be appreciated that if the door were to operate as a rigid unit it was necessary for the cables, chains or braces to be absolutely taut. Adjustment as to exact length was difficult to obtain and after t was obtained it would not last very long. The constant strain to which they were subjected would cause them to grow or increase in length with the result that there would be a certain amount of play between the door wings causing a noisy chattering operation of the door.
V. The cables, chains or braces formed an attractive nuisance for children who would hang or sit on the cables, chains or braces. This would sometimes cause injury to the children and at other times would cause the door to collapse or under any circumstances, it would stretch or distort the cables, chains or braces.
VI. The cables, chains or braces interfered with the appearance of the door and made the door undesirable from the architectural standpoint. At the point that the cables, chains or braces were connected to the door wing it was necessary to have an opaque panel. This panel was necessarily located adjacent the central portion of the door because the cables, chains or braces had to be connected intermediate the supporting disks which are provided adjacent the top and bottom of the central shaft or column. It was accordingly impossible to make a clear-vision door having a transparent panel extending almost the entire length of each door wing.
The plaintiff claims that Blanchard provided a practical solution of all these problems by inventing a type of door which eliminated these disadvantages. Plaintiff's invention consisted of the provision of a detent supported by the door wing and engageable in a keeper or recess provided in the periphery of the disk mounted on the central supporting column. There is a spring attached to this detent which when pressed pushes the detent into engagement. The pressure or tension of this spring is subject to adjustment which can be regulated by a skilled mechanic. Thus, a doorway can be set up in any building subject to any pressure required to normally operate the doorway by persons entering into and egressing from the building. Mechanically, these doorways can be installed with whatever pressure is needed to meet the existing conditions of any building. The tension or pressure of the spring can be temporarily reduced or disposed of entirely by a porter or building employee by the simple operation of an exposed manipulator on the outside of the door. This would permit the collapse of the door wing without interfering or destroying the adjustment referred to above.
The invention, therefore, consists of a combination of four elements, (1) the detent, (2) the tension or pressure means for applying force to the detent, (3) the adjusting mechanism for adjusting the amount of force exerted by the tension or pressure means, and (4) the exposed manipulator for temporarily reducing the force without disturbing the adjustment that forms the essential part of the invention.
The detent is represented in the drawings of the patent (figure 2) as a round ball (No. 11), approximately one-half inch in diameter. The spring is adjacent to and attached to this ball or detent and is about two inches long (No. 25). At the end of the spring and connected therewith is a screw threaded plug (Nos. 19, 20 and 21) which is the adjustment mechanism for adjusting the force to be exerted by the spring on the detent or round ball. This screw threaded plug can be adjusted at will by a skilled mechanic to meet whatever conditions exist at the time the doorway is installed. The handle which constitutes the exposed manipulator can be readily seen on each door wing near the top. The force exerted by this two inch spring can be temporarily adjusted so that ...