(See also [p. 82].)
[2139]. Crank motion to describe ovals (egg shaped, not true ellipses).
[2140]. Ellipsograph. The point A is fixed and the point B travelled along the line A B.
[2141]. String ellipsograph; A and B are fixed in the foci of the ellipse and the string joined so that the pencil C (with string wheel on it) will reach the end of minor axis D; the pencil will describe a true ellipse.
Section 36.—EXPANDING AND CONTRACTING DEVICES.
(See also [p. 84].)
[2142]. Expanding gate. Formed of vertical, round, or simple bars, fitted with sliding ferrules having centre pins passing through diagonal bars, these centres being evenly spaced.
[2143]. Expanding mandrel; has three parallel feathers, expanded by a central bolt having two equal cones.
[2144]. Expanding socket, formed of spring wire.