Patent GB-1008785-A (GB)
Title: Tamping equipment for railway tracks
IPC: E01B27/16
Filed: 1961-09-11
Abstract: 1,008,785. Railway track tamping machines. CANADA IRON FOUNDRIES Ltd. Sept. 11, 1961 [Sept. 9, 1960], No. 32576/61. Heading EIG. A machine for tamping the ballast of a railway track comprises a pair of tamping heads mounted one above each rail, each head comprising a pair of tamping units 30, the units of each pair being mounted to engage the ballast on opposite sides of a sleeper, Fig. 6, and each tamping unit comprising two pairs of tamping fork arms 35 each pair being secured to a shaft 37, Fig. 3, which is oscillated about its axis by a connecting rod 43 acting between a rocker arm 42 fixed to the shaft 37, and a crankshaft 48 driven by an electric motor 55. The fork arms 35 are thus oscillated about the axis of their drive shaft 37 to tamp the ballast beneath a sleeper. Each tamping unit 30 is mounted for pivotal movement about a horizontal pin 31 on a sliding frame 29, which can be raised and lowered relative to the track. Two units 30 are mounted on each frame 29 and each unit may be pivoted about its pin 31 by two hydraulic jacks 70 to compact the ballast under the rail tie. Each unit 30 is also provided with a pivot post 23 at right angles to the pin 31 so that if one of the forks 35 in a pair meets an obstruction then the other fork of the pair may continue to compact the ballast, as the unit pivots about the post 23. Each sliding frame 29 is reciprocated, on guides 28 secured to the frame 25 of the rail travelling vehicle shown in Fig. 1, by an hydraulic cylinder 85. The piston rod of each cylinder 85 is secured to a cross head 82. Bumper cylinders 96, 97 are connected in parallel with the cylinder 85 and provide maximum resistance to movement of the sliding frame 29 in its lowered position with the bumber cylinders bottoming against cross-members of the frame 25. A lazy tang 100 is secured to a lug 99 at the base of each cylinder 85 and as a the respective frame 29 is lowered the tang 100 grips the rail and prevents the vehicle from being raised as the forks 35 are forced into the ballast.  Operation In operation the vehicle is driven along the track by hydraulic motors on each of its wheels (not shown) and is positioned over a sleeper. The motors 55 work continuously and hydraulic fluid under pressure is fed to the cylinders 85 and the cylinders 96, 97, simultaneously to lower the tamping heads to engage the ballast. Each tamping head is lowered until either the frame 29 operates a limit switch 123, Fig. 1, to stop its downward movement, or until the pressure in the cylinder 85 reaches a predetermined limit and the pressure is released by a pressure switch (not shown). Thus if the forks 35 meet an obstruction before they have reached the end of their downward travel, the pressure in the cylinder 85 will be released. After the tamping heads have been lowered the jacks 70 are actuated to pivot the units 30 about their respective pins 31, until a predetermined pressure is built up when the pressure in the jacks 70 is released by a switch (not shown). The jacks are then operated to pivot the units 30 back to their original position, the heads are raised to operate a top limit switch 122 and the vehicle is moved to the next sleeper. The machine may be operated in this sequence automatically or manually by push buttons, and with automatic operation a switch arm 295, Fig. 1, contacts a sleeper and stops the vehicle in the correct position after operation of a time delay relay, and also initiates the sequence of operation. The machine may operate to tamp each sleeper twice before moving on, or to tamp every other sleeper only. Both the tamping heads may be operated together or one may be operated independantly of the other. When each tamping head is fully raised it may be held by a hook 108, Fig. 6, which engages with a V-shaped member 106, on the frame 29. This hook may be released by a hand lever (not shown). Specifications 1,008,786 and 1,008,787 are referred to.