Sears filled for Silvertone as a trademark in late 1915 to be used as a house brand for a line phonographs and records. It was approved in early 1916 with their first models appearing in their Spring 1916 catalog.[1][7] Beginning in the 1920s, the brand was expanded to include Silvertone radios and again expanded in the 1930s to musical instruments, superseding the previously-used Oxford branding. https://en.wikipedia.org/wiki/Silvertone_(brand)