We have observed a large sample of spectroscopic binary stars in the Hyades Cluster , using high resolution infrared spectroscopy to detect low mass companions .
We combine our double-lined infrared measurements with well constrained orbital parameters from visible light single-lined observations to derive dynamical mass ratios .
Using these results , along with photometry and theoretical mass-luminosity relationships , we estimate the masses of the individual components in our binaries .
In this paper we present double-lined solutions for 25 binaries in our sample , with mass ratios from \sim 0.1 - 0.8 .
This corresponds to secondary masses as small as \sim 0.15 \mathit { M _ { \odot } } .
We include here our preliminary detection of the companion to vB 142 , with a very small mass ratio of \mathit { q } = 0.06 \pm 0.04 ; this indicates that the companion may be a brown dwarf .
This paper is an initial step in a program to produce distributions of mass ratio and secondary mass for Hyades cluster binaries with a wide range of periods , in order to better understand binary star formation .
As such , our emphasis is on measuring these distributions , not on measuring precise orbital parameters for individual binaries .