Speaking of Hoover timelines here is a series timeline I found albeit it's not complete.
Sweepers
1930 - Dustette
1952 - Constellation
1955 - Pixie (replaced Dustette here)
1956 - Lark
1957 - Convertible
1962 - Portable
1963 - Dial-A-Matic
1964 - Slimline
1965 - Lightweight Upright (replaced Lark Upright; called Junior in the U.K.)
1969 - Portable Super (wheeled version of the Portable)
1970 - Swingette
1972 - Handivac (replaced Pixie)
1973 - Celebrity (replaced Constellation)
1975 - Portapower (replaced Swingette; would also replace the Portable and Slimline after 1980)
1978 - Concept One (replaced Dial-A-Matic)
1981 - Spirit (replaced Celebrity)
1982 - Dimension (upscale version of the Spirit line)
1983 - Concept Two (same as Concept One, with Help-Mate hand vac included); Decade 80
1986 - Innovation (called Turbomaster in the U.K.)
1988 - Elite (replaced Convertible; BOL versions called Turbolite in the U.K.)
1989 - Sprint/Tempo (replaced consumer-line Portapower)
1990 - Legacy (replaced Innovation); Futura (replaced Spirit)
1991 - Supremacy (this was an upscale line of uprights and canisters; the canisters were based on the former Spirit line)
1997 - WindTunnel
Sudsers/Steamers
Attachment: 1930s?
Floor Washers (w/Pick Up) - 1950s - 1966
Dual Brush Polishers (& Rug Cleaners): 1940s (Models 0211, 0212); 1960s (Model 5000s, 5100s, 5300s--Mickey Mouse-style); 1980s (Model F2000s); 2010s (Models F2300s); 2010s FloorMate Deluxe (Models FH400000s)
Shampoo-Polishers 1962 - (Model 5400s--Mickey Mouse-style); 1980s (Models F4200s); 2010s FloorMAX Supreme (Models F4300s)
Shampoo-Polishers w/Pick Up: Floor-A-Matic 1967-87 (Models 5000s); Scrub N Vac 1987 - 2001 (Models F5000s); FloorMate SpinScrub: 2001 - (Models FA300s, H3000s, FH40000s)
SteamVacs: 1994- (Models C3800s); SteamVac WidePath (Models F6000s): 1999 -
Commercial Single Brush - FloorMAX 1999 - (Models C5000s)