Railroad Gazette/Volume 38/Number 5/Railroad Shop Tools
Railroad Shop Tools.
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SLOTTING MACHINES.
The accompanying illustration, Fig. 1, shows the 24-in. slotter made by the Niles works of the Niles-Bement-Pond Company, New York. This tool is designed for heavy forge work and is of the geared type. The ram is driven by rock and pinion with tangent gearings at the side, as shown. The ram guide is adjustable by means of screws at the sides. The distance from the face of the ram to the column is 37 in. and the height of the ram guide is 31 in. The tool clamps are arranged so that they can be removed, thus leaving the face of the ram free for the relief tool-holder at the bottom of the ram. The circular table is 50 in. in diameter and has four corner clamps. It has a longitudinal adjustment of 40 in., a transverse adjustment of 36 in., and it is graduated. The feed is actuated by steel tappets on the ram. These are in the correct position when adjusted for the length of stroke. The feed operates at the top of the stroke, thus obviating the dragging of the tool over newly cut surfaces. The belts are shifted by means of a patent shifter, shown on the side of the machine, and all operating cranks are placed within easy reach of the operator.
Fig. 1—The Niles-Bement-Pond 24-in. Geared Slotter.
Fig. 2 shows an 18 in. crank slotter made by the Bement, Miles works of the Niles-Bement-Pond Company, New York. The maximum stroke of this tool is 18½ in., the height between the table and frame is 21 in., and the distance from the front of the tool apron to the column is 34 in. The working surface of the table is 36 in. in diameter, and it has a longitudinal traverse of 41 in. and cross traverse of 36 in. The cutter bar has a spring relief tool apron with both vertical and horizontal clamping surfaces. When bolt driven, countershaft pulleys 22 in. in diameter by 5½ in. face are furnished, and these should run at 110 and 170 r.p.m. The machine shown is driven by a 7½ h.p. motor having a speed range from 700 to 1,400 r.p.m. The motor is mounted on a bracket at the rear of the frame and is connected with two sets of gearing within the frame. Between the two sets of gearing there is a clutch, which is operated by a lever extending to the operating side of the machine, as shown. With the motor speed range and the two runs of gears, cutter bar strokes from 6½ to 29 per min. are obtained.
Fig. 2—The Niles-Bement-Pond 18-in. Crank Slotter.
Fig. 3 shows a 15-in. traveling head slotter made by the T. C. Dill Machine Company, Philadelphia, Pa. Owing to the adjustable head, a wider range of work can be done on this machine than can be done on the ordinary design of slotter. An intermittent feed is provided for operating the head, and feeds the tool to such work which is too cumbersome to be fed to the tool. The head is also arranged so that it can be clamped rigidly in any position, and on work not needing an extended reach, the cutting bar can be brought back close to the column, thus making the machine very rigid. When the cutting car is close to the column and the table is brought forward to its limit, the outside of work of large diameters can be machined. A quick traverse gear is provided for moving the head and compound table in all directions by power; the value of this as a time and labor saver is of importance in setting work to a line, or to a surface already machined. A pointer or tool can be placed in the tool post and the machine proper can be thrown out of gear, leaving the cutting bar stationary. The quick traverse gear can then be thrown in and the work can be set by moving the work or the tool forward and backward by power. This feature is also of use in setting the tool in position for another cut; thus, when one cut is finished, power is applied in bringing the tool to its first position, ready to start the new cut. This can be done while the machine is in motion or at rest, as desired. The quick return in this machine is accomplished by the main driving gear moving in a path eccentric to the crank shaft and connected thereto by means of a link. The quick movement begins just before the tool gets to the bottom of the stroke. This assures a constant cutting speed and moves under the bottom center at a high speed, making an accelerated up stroke; the quick part of the stroke, however, is at a point when there is but slight movement to the cutting bar. This affords a saving in power and in wear and tear on the machine. There is a safety device provided for the quick traverse gear and intermittent feed. This is arranged so that should the head or table receive undue strain, it would be thrown out of gear, and thus prevent the machine from being injured. A stroke indicator is provided which indicates the amount of stroke the machine is set to, and a hand wheel controller is also provided for arresting the motion of the machine after the power has been thrown off. The tool post is fitted in a relief apron which facilitates the changing of tools, and the table, which is 34 in. in diameter, is graduated in degrees, so that it can be readily set to any desired angle. The cutter bar has a wide range of adjustment, and in many instances work can be done which requires double the rated stroke of the machine. Six changes of speed are obtainable by means of the three step cone pulley and the back gears. When the machine is fitted with a constant speed motor the speed changes are obtained by means of a speed box. The principal dimensions of this machine are as follows: Length of stroke, 15½ in.; longitudinal movement of table, 36 in.; transverse movement of table, 30 in.; movement of head, 21 in.; distance from the table to the ram when in highest position, 24 in.; distance from the table to the ram when in lowest position, 1½ in. This machine will cut to the center of a 72-in. circle and will cut to the outside of a 90-in. circle; and its net weight is between five and six tons. A machine of this type is in use in the Renovo shops of the Pennsylvania Railroad, where it is giving satisfaction.
Fig. 3.—Dill Traveling Head Slotter.
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