Well, the Cleveland Vibrator company was founded in 1923:
But, in 1917, Hamilton-Beach had a "Type-D" vibrator with case, sold as an
accessory to promote "good health and muscle tone" through vibrations and
massage (right :-)
http://hambeach.dn.net/geninfo/antiques/vibecase.html
This was later replaced with the 1921 Type "C" vibrator, with single round
accessory:
http://hambeach.dn.net/geninfo/antiques/handvibe.html
Although, the best site has to be the Antique Vibrator Museum:
http://www.goodvibes.com/museum.html
Which reveals Victorian medical use of vibrators for curing "hysteria"...
- Jim