. Appleton's dictionary of machines, mechanics, engine-work, and engineering. While the screw is being cut or chased it is held in its hole in the rim of the carrying-wheel by meansof a roller v within the rim of the wheel, and turning on a stud-pin at the end of a lever w\ which turnson a fulcrum-pin x, the roller being held against the inner periphery of the rim of the wheel by apressure-screw y that bears against the lower end of the lever, so that as the blank is carried up bythe wheel to be presented to the dies, the pressure of this roller against the head holds it firmly in therim of th
. Appleton's dictionary of machines, mechanics, engine-work, and engineering. While the screw is being cut or chased it is held in its hole in the rim of the carrying-wheel by meansof a roller v within the rim of the wheel, and turning on a stud-pin at the end of a lever w\ which turnson a fulcrum-pin x, the roller being held against the inner periphery of the rim of the wheel by apressure-screw y that bears against the lower end of the lever, so that as the blank is carried up bythe wheel to be presented to the dies, the pressure of this roller against the head holds it firmly in therim of the wheel. The machine can be made double for threading two screws at one and the sametime, as shown in the figures, by having two carrying-wheels on the same shaft, and two mandrels withtheir jaws, dies, and sliding-rods, the two mandrels being geered together by two cog-wheels z z. 3274,. It will be obvious from the foregoing that, instead of the segment COg-wheel for giving the recipro-cating motions to the carriage of the carrying-wheel, this may be done by a. segment volute-cam, the faceof which shall act alternately against the front and back faces of (lie open space of the bar attached tothe carriage, as the object is simply to give a regular reciprocating motion to the carriage, particularlyduring the operation of threading; for during that operation the motion of the carriage must be regularto give a regular pitch to the thread. As it is only important to give a regular motion to the carriagein the operation of threading, the segment-cog or the volute-cam need only act in this direction, and themotion to run back the carriage, for the presentation of the blank may bo given by a separate cam of amore sudden curve, or an arm of greater length to perform the return motion faster ; but us these are 602 SCREWING MACHINE FOR BOLTS. well-known mechanical equivalents, t
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Keywords: ., bookcentury1800, booksubjectmechanicalengineering, bookyear1861
