I could not find any patents regarding the preparation of aluminium hydride, but I did find this one on aluminium lithium hydride :
Patent GB707851 (http://l2.espacenet.com/dips/viewer?PN=GB707851&CY=gb&LG=en&DB=EPD)
John Lennon - Working Class Hero
Why mill AlH3 and LiH together to form LiAlH4, when you must make the AlH3 from AlCl3/LiH anyway? Just throw in an extra equivalent of LiH in the same pot, just like in the document on my page:
https://www.thevespiary.org/rhodium/Rhodium/chemistry/lah.synthesis.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/lah.synthesis.html)