. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fig. 7.—The Rogers-Bond comparator. shown in the figure. These stops are arranged to be adjusted at any desired position alongthe guides, and are securelv held by clamping on the under side by the handles G and stops are each provided with a pair of electro-magnets, I and J, the poles of which donot quite come in contact with the armature seen at either end of the is made at Aand L,
. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fig. 7.—The Rogers-Bond comparator. shown in the figure. These stops are arranged to be adjusted at any desired position alongthe guides, and are securelv held by clamping on the under side by the handles G and stops are each provided with a pair of electro-magnets, I and J, the poles of which donot quite come in contact with the armature seen at either end of the is made at Aand L, which are hardened steel surfaces, tempered and polished, and82 498 MEASURING-INSTRUMENTS, MECHANICAL. placed as nearly as possible in the center of mass of the plate and of the stops. The magnetsare intended to overcome the unequal pressure due to ordinary contact, a rack and pnnon be-ing used to move the plate. The magnets are used to lock the microscope-plate at each endof the traverse between the slops. The use made of this slidmg microscope-plate and the. stops we shall see presently. Beyond the main base just described, and supported also onbrick piers, is an auxiliary heavy cast-iron frame A, wliicli is provided witli lateral and ver-tical motion witliin llie limits of zero, and of 8 and 10 in. respectively, for rough or ap-|>roximat, wjiiclislid.; from cud to end. a distance of about 40 in. Upon tliese sliding carriages are placed ta-bles 7and T\ provided with means for minute adjustment, for motion lengthwise, sidewise,and for leveling, thus i)ermitting the adjustuu-nt of a standard yard-bar ((uickiy, and witli-out the necessity of its being touciied wilii tlie hands after being placed upon tlic table untUthe work of comparison is completed. The first operation in the use of this form of comparator is to level the main base A(Fig. 9), then sliding the microscope-plate D from end to end of the steel tubular guides, MILLING-MACHINERY, GRAIN. 499 having th
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Keywords: ., bookcentury1800, bookdecade189, booksubjectmechanicalengineering
