Patten, who has challenged a fine of more than £9,000 for swearing from the All England Club, and Heliovaara won their first major title together at Wimbledon 12 months ago and then triumphed at the Australian Open in January.
Cash said he and Glasspool “took inspiration” from Patten and Heliovaara’s excellent start as a pairing but added they had “nothing to fear” against opponents they train with regularly.
The pair won back-to-back titles at Queen’s and then Eastbourne before Wimbledon.
“We came into this wanting to win the title and we’d probably be disappointed with anything less,” Cash said on Monday.
Each of the remaining Brits in the draw will believe they can lift this year’s trophy, with Salisbury and Skupski both winners of multiple Grand Slams.
They were also in mixed doubles action on Monday – but with mixed fortunes.
Salisbury reached the semi-finals alongside Brazil’s Luisa Stefani with a 7-6 (9-7) 6-3 win over Poland’s Jan Zielinski and Hsieh Su-wei, of Taiwan.
But Skupski and American Desirae Krawczyk lost 7-5 7-6 (9-7) to second seeds Marcelo Arevalo, of Argentina, and China’s Zhang Shuai – who will meet Salisbury and Stefani next.
Britons Joshua Paris and Eden Silva lost their quarter-final to Czech player Katerina Siniakova and Dutchman Sem Verbeek 7-6 (7-5) 6-3.