The 1837 patent nomenclature is hard to decipher but it seems like:
Snead = the main wooden shaft (what I would call the handle) (Fig. 1)
Nib or thole iron = the iron brackets that attach the small handles (nib or thole woods) to the snead (Fig 1-a, Fig.2 and Fig. 4)
Snath = the snead (handle) with all it's parts (Fig. 1)
Fig.1-B is the ring used to fasten the scythe to the snath
Fig. 7 is a wrench.
Late 1800's and early 1900's catalogs lists the snath as the iron part that fastens the blade to the handle (snead). See an earlier post with a picture of my salesman sample snath with wrench mounted on a partial handle.
http://www.papawswrench.com/vboard/index.php?topic=169.msg1053#msg1053The 1837 patent would be one of the first numbered patent to show an auxiliary wrench after the unnumbered patents showing auxiliary wrenches: No. 6,338X issued Jan. 12, 1831 and No. 9,474X issued Mar. 04, 1836. The first known patent for a wrench is 6,271X issued Dec. 14, 1830.
This 1837 patent is not on DATAMP yet, rest of the patents above are listed.
The complete 1837 patent can be seen at Google Patents:
http://www.google.com/search?tbo=p&tbm=pts&hl=en&q=patent:144&num=10