formed by the intersection of the plane m l (Fig. 6)
with the cone h p s. The hollow fillet v c (Fig. 6), con-
sisting of a segment of a cylinder whose axis is parallel to
that of the cone, its line of penetration v x, Fig. 3, will be
obtained by conceiving planes perpendicular to these axes,
as exemplified in our illustrations of the penetrations of
The hollow fillets round the bosses of the studs a, C' o, c
(Figs. 1 and 2), form, by their intersections with those of
the horizontal feathers, curves which are projected in
Fig. 1 in small straight lines. In Fig. 2, these curves
being concealed, are represented in dotted lines. In this
latter figure the outline of that portion of the feather which
connects the boss of the centre C with that of the stud o,
is a circular arc a b', which, passing through the point a',
whose distance from the centre line is specified, must be
a tangent to the straight line b' c, the position of which
may easily be obtained if we remark that its extremities
b' and c are slightly nearer the centre line E E' than the
respective distances (4 and ST inches) of the bosses which
Lastly, in Fig. 7, the curve of penetration of the cylin-
drical and spherical portions of the cross-head E, may
easily be found by taking a few horizontal sections
according to the method pointed out in previous examples.
In executing this, and all the succeeding drawings, the
student should be careful to work from the dimensions
given on the figures, and not merely to copy the lines in
the Plate. These dimensions are not all noted on the
general views, but are distributed over all the figures;
which arrangement presents the advantage not only of
avoiding confusion and frequent repetitions, but also of
directing the attention of the learner more forcibly to all
the minuter peculiarities of form in the object upon which
he is engaged.
Details of a Steam Engine Connecting-Rod and
The connecting-rod B, which is represented in front and
side elevation at Figs. 1 and 2, consists generally of a
cast-iron bar or beam, strengthened throughout the
greater part of its length by four ribs or feathers, whose
outlines in the direction of their length are parabolic
curves,* as in the case of the beam. Its upper extremity
is formed into two projecting arms, upon each of which a
close wrought-iron strap G is fixed by means of a key or
cotter c. These straps are provided and formed for the
reception of the brass bushes a and 6, which are accurately
fitted to the journals or bearings of the crossdiead E,
which has been fully represented and described in the
preceding Plate, and which, with its retaining ferrule F,
are here shown in dotted lines.
The lower end of the connecting-rod, which is intended
to act freely, but without play, upon the pin H of the
* The mode of delineating one of these curves, is shown to the
right of Fig. 2.
crank D (so as to impart to the latter the motion which
it receives from the beam), is made of a form suitable for
the reception of the brasses and other adjusting mecha-
nism necessary for this purpose. In the example now
before us, the end of the crank-pin is concealed by a
slight brass cover or disc I, fixed to the connecting-rod by
two small screw pins, which serves to protect the working
surfaces from dust, and imparts an elegant finish to the
In Fig. 3 the ends of the connecting-rod are represented
upon a scale of double the magnitude of the preceding
figures. In Fig. 4 one of the upper links or straps, with
its adjusting apparatus, is supposed to be cut by a vertical
plane passing through the axes, so as to expose the inte-
rior arrangement. This section exhibits distinctly the
mode of fixing the links upon the arms of the connecting-
rod by means of the cotters c, c, and projecting discs e e,
cast upon the arms; as also the contrivance for retaining
the brasses a and b in their places. Fig. 5, which is a
vertical section on the line m N (Fig. 3), shows the cor-
responding provisions for the lower end of the rod; a
small oblique hole for the introduction of oil will be
observed in the upper brass n, while the lower to is
formed with a spherical projection entering a concave
recess in the cast-iron, for the purpose of preventing its
displacement by the friction of the crank-pin H, which
is regulated and adjusted by the cotter d.
Fig. 6 shows detached views of one of the upper links
Fig. 7. A face view and section of the disc or cover I.
Figs. 8 and 9. Detached views of the upper and lower
brasses of the top links of the connecting-rod.
Figs. 10 and 11. Similar representations of the bushes
of the lower end.
Fig. 12. A section on the line P Q (Fig. 4). This view
is necessary, as the form of this part could not be accu-
rately ascertained by any of the other views.
Fig. 13. A horizontal section on the line R S, showing
the form of the body and feathers of the rod.
Fig. 14. Another horizontal section on the line T Y.
The crank D, shown in dotted lines in Fig. 2, and fully
represented at Figs. 15, 16, and 17, consists of a single
strong casting, fitted immovably on one extremity to the
shaft 0, which is to receive the motion of rotation, and
provided, at the opposite end, with a strong eye or boss,
accurately bored out for the reception of the crank-pin,
which is also fixed permanently and firmly in its place,
and retained by a pin or cotter.
Illustrations of the Conversion of Reciprocating
into Rotatory Motion.—Plate XXX.
We now enter upon the consideration of the combina-
tions of parts employed in the conversion of reciprocating
into rotatory motion, or vice versa; and, in the Plate now
before us, we present some varieties of such constructions.
Fig. 1 represents a combination of parts similar to
those whose details have formed the subjects of the two