US 4,068,595 AGranted

Track tamper

AssigneeGraystone Corporation

InventorsRobert A. Weber, Franz Allmer

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Abstract

Opposed pivotally mounted tamper arms are oscillated by respective single-acting hydraulic piston assemblies controlled by separate hydraulic duplex rotary distributing valves. Fluid supply and return lines for each piston assembly are connected to a source of pressurized hydraulic fluid via the 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 respective piston assembly and the supply and return lines. While the rotary valves are preferably driven by a common drive unit, the relative phase of the oscillations of the arms can be determined by rotationally offsetting one of the spools with respect to the other by the desired phase angle.

Claims10

Dependent claims

Track tamping apparatus of the type comprising a pair of opposed, vibrating tamper arms pivotally mounted on a carriage having means for positioning corresponding lower ends of the tamper arms on either side of a railroad tie and for drawing the vibrating arms together to compact the ballast thereunder, wherein the improvement comprises:

a pair of hydraulic piston assemblies operatively connected between the carriage and the upper ends of said tamper arms respectively such that reciprocation of each piston assembly causes pivotal reciprocable vibration of the respective tamper arms to aid in compacting the ballast, each said hydraulic piston assembly having a supply line and a return line for filling and evacuating hydraulic fluid from said piston assembly, respectively;
a pair of rotary valve means connected respectively to said piston assemblies for alternately communicating the supply and return lines for said respective piston assemblies with a common source of pressurized hydraulic fluid;
and
drive means for imparting continuous rotation to each said rotary valve.

1 more element

Dependencies are inferred from the claim text.