Improvements in the Construction of "Built" Crank Shafts and Repairing of Solid Shafts.
Year: 1887

page_text: Date of Application, 20th Dec., 1887
Complete Left, 27th Jan., 1888
Complete Accepted, 23rd Mar., 1888
PROVISIONAL SPECIFICATION.
Improvements in the Construction of "Built" Crank Shafts and
Repairing of Solid Shafts.
We HENRY FOWNES and GEORGE EDWARD FOWNES of 31 North View, Heaton in
the City and County of Newcastle upon Tyne, Engineers, do hereby declare the
nature of said invention to be as follows:-
Our invention relates to improvements in the mode of fitting and securing crank
pins in the webs of what are known as "built" crank shafts-in which the crank.pin
forms a separate piece from the webs-and is designed specially to enable such shafts
to be adapted to existing engines in which provision as to clearance is provided only
for solid shafts, and is not sufficient to allow for the introduction of a pin separate
from the webs as ordinarily fitted; but it is equally suitable for crank shafts of new
engines in which it reduces the length over the end of web and further relates to
improvements in replacing a broken crank pin of a solid shaft, thus securing the
advantage of a built shaft, as to the separate pin and the facility for fitting a
spare pin.
According to our invention we form the pin with a collar at each end, concentric to
the axis of the pin, which collars are sunk into the inner faces of the webs and beyond
each collar the pin extends through the web with its axis eccentric to the main axis
toward the centre of the shaft. Thus the pin is firmly secured against turning round
and the webs may be secured against spreading by keys or by nuts, or the webs may
be shrunk onto the pin, whilst there is sufficient material in the web outside the pin
to secure the requisite strength and a crank with a pin thus fitted into webs is no
longer, from centre of shaft over the webs, than a solid crank.

page_text: On the accompanying sheet of drawings we have illustrated the manner in which
we propose to carry out our invention in practice but we do not bind ourselves to 2
proportions of parts nor to minor details.
Fig. 1 is an elevation partly in section of one portion of a crank shaft with the
webs W W and pin P with concentric collars C and eccentric ends forming
separate parts.
Fig. 2. is an end view of the outer face of the web W with both ends semi- 3
circular.
Fig. 3 is an end view of the inner face of the web W1 with the outer, or pin, end of
radial form with the object of providing more material around the insertion of the
pin P. The dotted lines around webs indicate the outlines of crank webs of various
forms, as ordinarily made to receive separate pins, to show the material saved by 3
our method of fitting the crank pins,.as-also-the reduced clearance required. .

page_text: Fig. 1. shews different methods of securing the webs W W upon the body of
shaft S viz. by shrinking on the web W₁, and securing it with a feather key K, and
also by a collar on shaft S, recessed into web W and bolted through, but, except in
combination with the insertion of the crank pin P, we do not consider the mode of
securing the webs on shaft as forming any part of our invention.
The pin P is perfectly secured against turning round and the keys K' are intended
merely to prevent any tendency of the webs W W to spread or open out.
Having now particularly described and ascertained the nature of our. said
invention and in what manner the same is to be performed we declare that what
we claim is :-
The improvements in the construction of crank shafts, having the crank pin separate
from the webs, or in the repair of damaged or broken pins of solid shafts; consisting
in forming the pin with collars, concentric with its main axis, recessed into the webs,
and with its ends eccentric to its main axis, toward centre of shaft, inserted in
corresponding holes in the webs; with the objects of reducing the length over ends
of webs, providing the requisite material for strength of webs and preventing the pin
from turning round substantially as described and shewn.