Mobile track tamping machine

Claim 1

A mobile track tamping machine mounted for continuous advancement in a working direction at a selected forward speed on a track including two rails fastened to successive ties resting on ballast defining cribs therebetween, for tamping ballast under the successive ties during the continuous advancement of the machine, which comprises (a) a frame, (b) a tamping tool carrier vertically adjustably mounted on the frame, the carrier being mounted for rotation about a horizontal axis extending transversely to the track and being substantially symmetrical with respect to the axis of rotation, and the carrier including (1) an annular support concentric about the axis of rotation, (c) a drive for rotating the tamping tool carrier at substantially the same speed as the selected forward speed of the machine, the drive including (1) a rotary shaft having two ends rotatably supported on the frame and extending in the horizontal axis, (d) at least one assembly of eight pairs of vibratory tamping tools mounted on the tamping tool carrier, the sixteen tamping tools extending in a vertical plane adjacent one of the rails, substantially radially with respect to the axis of rotation in a rest position and peripherally equidistantly with respect to the annular support for sequential immersion in the successive cribs during the continuous advancement of the machine and the rotation of the tamping tool carrier, the tamping tools having tamping jaws for immersion in the cribs and the distance between the jaws of adjacent ones of the tools approximating the average combined width of a crib and a tie, and the drive rotating the carrier in a direction imparting to the tamping tools a movement opposite to the working direction of the machine, (e) a pivot on the annular support for each one of the tamping tools, the pivots extending substantially parallel to the axis of rotation for reciprocating the tamping tools in the vertical plane about the pivots thereof between the rest position and a tamping position, the diameter of the annular support being selected to enable the support to carry sixteen equidistantly spaced pivots for the tools, and (f) drive means connected to the tamping tools and arranged for reciprocating the tools of each pair about the pivots thereof towards each other from the rest position onto the tamping position and against a tie positioned intermediate the tamping tools of the pair.