. Appleton's dictionary of machines, mechanics, engine-work, and engineering. In 1820, Mr. James Allan was rewarded by the Board of Longitude with one hundred pounds,for his improvement on Ramsdens dividing-engine. This improvement consists in the method erfi-ployed to cut or rack the teeth around the periphery of the great circle, worked by an endless screw,upon whicli the arc to be divided is placed, so as to insure perfect equality of size, as regards the teeth,in all parts of the circle. This extremely ingenious, though simple contrivance of Mr. Allan, is describedin the transactions of th
. Appleton's dictionary of machines, mechanics, engine-work, and engineering. In 1820, Mr. James Allan was rewarded by the Board of Longitude with one hundred pounds,for his improvement on Ramsdens dividing-engine. This improvement consists in the method erfi-ployed to cut or rack the teeth around the periphery of the great circle, worked by an endless screw,upon whicli the arc to be divided is placed, so as to insure perfect equality of size, as regards the teeth,in all parts of the circle. This extremely ingenious, though simple contrivance of Mr. Allan, is describedin the transactions of the Society of Arts. The great circle of bell-metal, a semi-plan of which is shownin Kig. 34-21. is mounted upon an axis A, and its surface made truly plane and perpendicular to theaxis ; the section shows the figure of the axis, and the central ring B, to give the greatest strength tothe circle; C is a section of a portion of the frame of the engine ; and D, a socket into which the axisA is fitted; the circumference of the large circle is then turned to such a figure as to
Size: 1586px × 1575px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmechanicalengineering, bookyear1861
