I saw this strange device being demonstrated by its enthusiastic inventor at the Windsor IOG / Saltex show in 1981. I think probably best summed up as “a good idea at the time – maybe”?
https://www.dropbox.com/s/4mt4u61k440vnxo/Thiel%20Autoshear0001.pdf?dl=0
EDIT
Would seem that the company / product didn’t last long.
In the Exeter County Court No. 19 of 1984 In the Matter of THIEL AUTOSHEARS LIMITED and in the Matter of the Companies Act 1948 A Petition to wind up the above-named Company presented on 28th November 1984 by the Company whose registered office is situate at Mouse Hall, Newton Poppleford, near Sidmouth, Devon, will be heard by Exeter County Court at The Castle, Exeter, on Friday, llth January 1985, at 10.30 a.m. Any Creditor or Contributory wishing to oppose or support must ensure that written notice reaches the undersigned by 1600 hours on Thursday, 10th January 1985. A copy of the Petition will be supplied by the undersigned on payment of the prescribed charge. Sargent and Probert, 6 Barnfield Crescent, Exeter, Devon EX1 1RG, Solicitors for the Petitionii Company. (29