Why does the word gobs mean a copious amount?

Gobs is a word I've never seen in print; however, I've heard it used in an old moving picture and in an old situation comedy. I'm curious to know the origin of the word gobs as well as when it was first used to mean a copious amount.

I heard it used in the 1930 moving picture Ladies of Leisure when Marie Prevost is ordering a meal at a restaurant and tells the server she'd like "gobs of cheese" on her dish (I believe it was cheese). The next time I heard it used was in an episode of Three's Company "Ground Rules" which aired in 1977. Jack Tripper is with a young lady at the Regal Beagle and tells her "we can have gobs of fun here."

Those are the two examples I have for hearing gobs used to mean a copious amount. Any ideas for why gobs is slang for a copious amount and any ideas as to when it was first used or which decade/decades it was most popular.

gob, gobs n.

Informal A large quantity. Often used in the plural: a gob of money; gobs of time.

It seems that the word has Gaulish (Celtic) origins {The Online Etymology Dictionary:Gob{2}(n.)}:

"a mouthful, lump," late 14c., probably from Old French gobe "mouthful, lump," related to gober "gulp, swallow down," probably from Gaulish *gobbo- (compare Irish gob "mouth," Gaelic gob "beak"). This Celtic source also seems to be root of gob "mouth" (mid-16c.), which is the first element in gob-stopper "a kind of large hard candy" (1928).

Google Ngram shows an increasing usage of the expression gobs of since the beginning of the 20th century.

350–1400; Middle English gobbe, variant of gobet gobbet...

...where gobbet: 1275–1325; Middle English gobet < Old French: a mouthful, diminutive of gobe.