Patent for a new and improved spring socket-iron for vehicles. This design "relates to thills and thill-couplings by means of which a more convenient and safe fastening for the thills or pole of a carriage or wagon are provided, whereby the thills are readily attached to or detached from spring-socket thill-irons, and the irons are securely locked in the ears of the axle-clips by means of flanged bolts working in recessed movable bushings in the ears of the clips and in the eye of the thill-irons" (lines 14-23).