This arrangement permits of the
roller being made to leave the trajectory in order that the carriage may
be drawn back to a sufficient distance from the tool when the wheel is
finished, so as to replace the latter by another.
One hollow is cut during each forward travel of the carriage; and, when
such travel is finished, a cam-disk, p, placed on the shaft, n,
lifts the tool-carrier, b, and thus draws the cutting-tool out of the
hollow cut by it, so that the carriage cam can then move back without
restraint. In the interim, the sleeve, h, which supports the wheel,
revolves one tooth through the following arrangement: On the axis, e,
of this sleeve there are two ratchet-wheels, r and s, the number of
whose teeth is equal to that of the teeth to be cut in the wheel. The
wheel, r, produces the rotation of the sleeve, h, and the wheel,
s, keeps the shaft stationary during the operation. The two wheels are
set in motion by a lever, t, or by its click, this lever being raised
at the desired moment on the free extremity of the driving shaft, n,
by a wedge, u. The short arm of the lever, t, engages, through its
point of appropriate shape, with the teeth of the wheel, s, so as to
keep this latter stationary while the tool is cutting out the interspace
between the teeth. When the lever, t, is raised, this point is at
first disengaged from the wheel, s; and the raising of the lever being
prolonged, the button, i, places itself against the upper curve of the
slot in the lever, q, and raises that likewise.
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