Today in 1948, US Patent 2451273 A was issued, an invention of Elvin M. Bright, for his “Method of Applying Bottle Caps.” There’s no Abstract, although in the description it includes this summary:
This invention relates to improvements in a method for thermoplastically capping bottles.
It is an important object of the invention to provide a method and means of capping a bottle which, to a large extent, will make use of standard existing bottle capping equipment and will provide a cap which will not interfere with the handling, processing, merchandising, and use of the bottle and its contents in accordance with conventional procedure.
From the standpoint of the process involved, a very important objective is to soften a thickened margin of the bottle cap blank without softening the remainder thereof, and to mold such thickened margin around the cap-receiving bead of the bottle and immediately to harden it thereon. In this connection I propose to utilize infra-red rays or other radiant heat for softening the flange of the bottle cap blank while shielding and thermally insulating the top of the blank from such rays. Infra-red rays are preferred because of the ease with which they may be directed and controlled.