Center-of-car cushioning device with gas return

Abstract

A cushion assembly having an outer cylinder and a metering cylinder extending between end caps and defining an annular reservoir therebetween with communication being provided by metering orifices distributed along the length of the metering cylinder. A piston is slideable in the metering cylinder having a first piston rod connected to one side and a second piston rod of hollow construction connected to the other side, the first piston rod having a head at its outer end. The head and the first end cap define a gap between them when the first piston rod is in its contracted state. Stop members on the slideable sill and frame of the car occupy normal side by side positions in register with one another in the gap, so that a shock applied to the sill in either direction causes the stop members to shift out of register with one another elongating the gap so as to tension and extend the first piston rod. The device is charged with a combination of hydraulic fluid and gas under pressure so that as the piston moves fluid restrictedly flows through the orifices from a position in front of the piston through the reservoir to a position behind the piston to cushion the shock, the second piston rod having a substantially greater diameter than the first, presenting a greater axially projected area to the pressurized fluid, so that the piston is promptly returned to its retracted state in readiness for a subsequent shock.