Track tamper with hingeable unitary pivotable tamping unit

Abstract

In a track tamping machine, opposed pivotally mounted tamping arms are oscillated by respective single acting hydraulic cylinders controlled by one or more hydraulic duplex rotary distributing valves. Fluid supply and return lines for each piston assembly are connected to a source of pressurized hydraulic fluid by way of a respective rotary valve. Each valve has a stationary ported shell which receives a rotary cylindrical spool having a pair of axially displaced supply and return throughports which alternately register with supply and return line ports in the shell to open and close the connections between the oscillating cylinder and the supply and return lines. Such oscillating cylinders are useful in controlling the vibration of the tamper arms in a track tamper unit. Accordingly, this disclosure particularly relates to a unitary, hinged, pivotable unit, to which such a tamping unit is secured, which hinged unit is readily adapted for conversion of an existing track tamper to incorporate the oscillatory drive features described above. The oscillating cylinder is located adjacent a squeeze cylinder and the cylinder pair is secured to an end of each of the tamping arms and to a support member of the tamping unit. The tamping unit is attached to and vertically movable relative to the hinged unit which in turn is laterally movable relative to a rail when secured to the tamping machine. Thus, the tamping tool is controlled as to its depth of penetration, throw of oscillation, and outward to inward movement. Alternate embodiments and features are also disclosed.