This is a suit for infringement of letters patent of the United States, No. 743,206, granted to August Weber, Sr., on November 3, 1903. The District Court held claims 1 and 4 valid and infringed, but the Circuit Court of Appeals, while affirming the validity of the claims, reversed the holding that they were infringed. A supposed conflict of this decision as to infringement with one by the Circuit Court of Appeals of the Second Circuit, with respect to the same patent, serves to bring the case here for review on writ of certiorari.
The patent is a simple and, as we shall see, a narrow one. As described in the specification it relates to new and useful improvements in incandescent electric lamp sockets, the principal object of which is to provide a simple and effective automatic lock or connection between the sleeve and the cap of such a socket.
Nothing new electrically or in the general form of the cap or sleeve is claimed-the invention relates solely to the method of fastening the overlapping cap to the sleeve, or, as it is sometimes called, the shell or casing.
The validity of the claims involved is conceded in argument, and, having regard to the disclaimer with respect to claims 2 and 3, which has been filed by the petitioner since the decision by the Circuit Court of Appeals, we regard the issue as now narrowed to the infringement of the fourth claim.
The familiar incandescent lamp consists of a glass bulb, attached to a screw threaded base, adapted to be screwed into a properly insulated block, through which the necessary electrical connections are made, and which is in closed by a cylindrical 'sleeve' of sheet metal. In order to compete the lamp this detached sleeve supporting the bulb and inclosing the insulated block must be fitted and securely fastened into the usual cap, which is attached to the wall or fixture, for if the fastening should become loose, the light might fail, or the bulb fall, or a fire hazard be created. To invent a device by which the sleeve and cap could be easily and securely attached to each other and yet be readily detached when desired, was the problem to which the patentee addressed himself, and his solution of it is thus described in the fourth claim of the patent:
'In a device of the class described, and in combination a pair of members comprising a sheet metal sleeve having a slotted end, and a sheet metal cap adapted to telescopically receive the slotted end of said sleeve, one of said members being provided with a recess, and the other having a correspondingly located transverse slit and the wall on one side thereof displaced to from a projection beveled or inclined toward said recessed member and terminating abruptly at said slit, whereby said members are adapted to automatically interlock with a snap action when telescopically applied to each other, and to be released by manual compression of said slotted sleeve, substantially as described.'
To make the device thus described, it was only necessary to cut two transverse slits, each about one-quarter of an inch in length, in opposite sides of the flange of an ordinary cap, and to then, with a punch or die, force outward the upper edges or walls of the slits to the extent desired to create the necessary 'recesses' which must 'terminate' at the lower, sharp edges of the slits. A similar operation on a slotted sleeve would produce a similar result, but when viewed from the outer surface of the sleeve the recesses would become the projections of the quoted fourth claim. When such sleeve is teles copically applied to-pushed or pressed into-the cap, it is obvious that with the recesses in the cap and the projections in the sleeve properly positioned and of a suitable size, when the projections shall register with the recesses, the resiliency of the metal will cause the two to engage with a snap action and the sharp lower edges of the slots in the cap will then prevent the cap and sleeve from being separated by a longitudinal movement only, until the sleeve shall be manually compressed to release the projections from the recesses.
It is to be noted, for it will be of significance in the interpretation of the claim involved, that it is required that the projections on the sleeve shall be 'beveled or inclined toward said recessed member,' and in the specification it is provided that the projections shall be 'beveled or inclined from the inner end of the sleeve toward the outer end.' With such construction it would seem plain, even without the exhibits, which show it to be true, that, friction aside, projections so beveled or inclined could readily be released by rotative movement from similarly shaped recesses without compression of the sleeve.