On this day in 1932 Gebhard Jaeger was granted the patent for Truck Concrete Mixer. U.S. Patent No. 1,867,838.
One object of the invention is more especially to provide an improved and simplified mixing drum having a cylindrical portion for terminating in a tapered discharge for a motor driven truck and means for mounting and rotating the same on a fixed horizontal axis on such truck whereby the concrete materials can be effectively mixed when the drum is rotated in one direction and the discharge of the materials caused by rotation of the drum in the opposite direction.
