Pipe ramming system with hydraulic crowd
A horizontal pipe ramming system includes a hydraulic crowd system. A hydraulic percussive hammer is mounted on a carriage that is urged forward by hydraulic cylinders acting between the carriage and an abutment. The continuity of crowd is enhanced by a compressive resilient assembly that releases its energy to the hammer to keep it in contact with the pipe after impact.
1. A horizontal pipe ramming system, comprising:
rails;
a carriage mounted on said rails:
a harness carried on said carriage, said harness cradling a percussive hammer for striking a pipe in horizontal alignment with said hammer;
said carriage being urged forward on said rails by hydraulic cylinders acting between the carriage and an abutment that is stationary in relation to said rails;
said harness comprising:
a first part of said harness that is fixed in relation to said carriage;
a second part of said harness that is displaceable in relation to said first part;
a resilient compressible assembly being interposed between said first and second parts;
said hydraulic cylinders acting to displace said first part in relation to said second part and toward said pipe, thereby compressing said compressible assembly against said second part; and,
said second part carrying said hammer;
said compressible assembly urging said second part and said hammer toward said pipe after said pipe is displaced by an impact of the hammer on said pipe.