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A plate fulcrum track scale
578
GEORGE O. SQUIER.
[J. F. I.
telegraph terminal. The plan outlined above for the case of ocean cables is similar in principle and is proposed for similar reasons. The present war has emphasized the supreme importance of ocean cables as never before in the history of the world, and as a result it is believed t.hat as soon as peace is established it will be well worth while to carefully consider a comprehensive plan of cable laying based on the maximum of international service. WASHINGTON,D. C., April 17, 1917. A Plate Fulcrum Track Scale. J. H. A. BOUSFIELD. (RailwayAge Gazette, vol. 62, No. Io, p. 395, March 9, I917.)--The Pennsylvania Railroad, one of the pioneers in the use of plate fulcrum track scales, recently installed the first two-section track scale of this type at Pitcairn, Pa. This form of construction eliminates the knife-edges which have been of practically universal application in scales of all kinds. In consequence of this change, the need for regrinding and renewing knife-edges and bearings is avoided. Similarly, dead rails or their equivalent in the form of relieving gears are avoided. As indicated by the name, a ~hin plate, continuous from lever to bearing, takes the place of the knife-edge. These plate fulcrums consist of relatively thin central portions connecting two heavier portions or heads. The thin portion gives the desired flexibility, while the large heads distribute the load on the supporting members and decrease the unit stresses. The thin central portions are all arranged to act in direct compression, but are subjected to a slight flexure as the weighing beams vibrate and the lever system responds to the condition of balance. Thus the necessary vibration is taken care of without entailing the inevitable wear that takes place with the knife-edge scale, and the thin plates of steel remain in their original condition, regardless of the amount of weighing that is done by the scale. The effective length of the weighing rail is 52 feet. The scale is of the two-section type, wherein four main transverse levers--two at each end of the track-supporting girder--transmit the load to two longitudinal extension levers, which in turn transmit to a transverse extension lever connected directly to the weighing beam. Only seven levers are used in the scale, ~chus effecting greater simplicity in construction than in the four-section type of scale with equal efficiency. The main girders are so designed that a test car can be placed directly over the centre line of a section, thus providing an effective means for accurate cali,bration. The main weighing beam is graduated to 3oo,ooo pounds by Iooo-pound notches and a fractional bar to iooo pounds by 5o-pound notches. An auxiliary weight is provided to raise the capacity to 4oo,ooo pounds. The plate fulcrum principle is that used for many years in the highly refined Emery 'testing machines.
GEORGE O. SQUIER.
[J. F. I.
telegraph terminal. The plan outlined above for the case of ocean cables is similar in principle and is proposed for similar reasons. The present war has emphasized the supreme importance of ocean cables as never before in the history of the world, and as a result it is believed t.hat as soon as peace is established it will be well worth while to carefully consider a comprehensive plan of cable laying based on the maximum of international service. WASHINGTON,D. C., April 17, 1917. A Plate Fulcrum Track Scale. J. H. A. BOUSFIELD. (RailwayAge Gazette, vol. 62, No. Io, p. 395, March 9, I917.)--The Pennsylvania Railroad, one of the pioneers in the use of plate fulcrum track scales, recently installed the first two-section track scale of this type at Pitcairn, Pa. This form of construction eliminates the knife-edges which have been of practically universal application in scales of all kinds. In consequence of this change, the need for regrinding and renewing knife-edges and bearings is avoided. Similarly, dead rails or their equivalent in the form of relieving gears are avoided. As indicated by the name, a ~hin plate, continuous from lever to bearing, takes the place of the knife-edge. These plate fulcrums consist of relatively thin central portions connecting two heavier portions or heads. The thin portion gives the desired flexibility, while the large heads distribute the load on the supporting members and decrease the unit stresses. The thin central portions are all arranged to act in direct compression, but are subjected to a slight flexure as the weighing beams vibrate and the lever system responds to the condition of balance. Thus the necessary vibration is taken care of without entailing the inevitable wear that takes place with the knife-edge scale, and the thin plates of steel remain in their original condition, regardless of the amount of weighing that is done by the scale. The effective length of the weighing rail is 52 feet. The scale is of the two-section type, wherein four main transverse levers--two at each end of the track-supporting girder--transmit the load to two longitudinal extension levers, which in turn transmit to a transverse extension lever connected directly to the weighing beam. Only seven levers are used in the scale, ~chus effecting greater simplicity in construction than in the four-section type of scale with equal efficiency. The main girders are so designed that a test car can be placed directly over the centre line of a section, thus providing an effective means for accurate cali,bration. The main weighing beam is graduated to 3oo,ooo pounds by Iooo-pound notches and a fractional bar to iooo pounds by 5o-pound notches. An auxiliary weight is provided to raise the capacity to 4oo,ooo pounds. The plate fulcrum principle is that used for many years in the highly refined Emery 'testing machines.