Tim, perhaps the following might help.
I have xerox copies of three patents:
1) No. 366,606, filed Nov. 18, 1886, granted Jul 12, 1887. Issued to Frank L. Pope, Henry M. Byllesby and Philip Lange, for a key socket. Assignors to Geo. Westinghouse, Jr.
2) No. 383,616, filed Sep. 1, 1887, granted May 29, 1888. Issued to Byllesby and Lange, for a lamp (with the bulbous Westinghouse end pin). Assignors to Westinghouse Elec. Co.
3) No. 434,153, filed Oct. 31, 1888. Issued to Lange on Aug. 12, 1890 for a socket. Assignor to Westinghouse Elec. Co. I can scan the sockets if you think it might help.