Improvements in the Construction of Crank Shafts.
Year: 1885

page_text: Improvements in the Construction of Crank Shafts.
VI, PETRONIUS HODGES 238 Barnsley Road, Sheffield in the County of York
Engineer do hereby declare the nature of my said invention for IMPROVEMENTS
IN THE CONSTRUCTION OF CRANKSHAFTS to be as follows:
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My invention relates to built up Cranks, and is particularly applicable to the
Cranks of Marine Engines, as it enables steam ships to carry duplicate parts of
such cranks which would be much less cumbersome than an entire crank shaft, and
more easily stowed.
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The object of my invention is not only to enable steam ships to carry duplicate
cranks with greater convenience of stowage, but to so construct, the cranks, that
they may be separated or taken to pieces in case of failure, and the faulty, part or
parts be, replaced quickly and with an minimum amount of labour, and when
properly put together shall form a perfectly rigid and trustworthy crank, most
important considerations in case of a breakdown at sea.
In carrying out my invention I make the crank-pin and the webs preferably of
one continuous piece of material, (but I may if desirable, make them separately
and fit them together).
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The webs are divided through the openings for the ends of, the crank shaft the
loose parts forming caps which are. provided with undercut recesses to fit-upon
Corresponding dovetails upon joint faces of the webs. The caps are put in position
by sliding them over the ends of the shaft sideways, on the dovetailed parts of the
webs where they are permanently secured by bolts and nuts. I'll crede
I use keys to take up any slackness of fit in the recesses and the dovetails before
mentioned, and I make the bolts (which secure the caps) to partially intersect the
said keys so that it is impossible for them to become loose.
To prevent the shaft turning in the web, I form upon the end of the shaft an
eccentric projection, or cam shaped collar, which fits into a corresponding recess
formed in the web, and acts as a key when the parts are put together.
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page_text: I PETRONIUS HODGES 238, Barnsley Road, Sheffield in the County of York
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN THE
CONSTRUCTION OF CRANK SHAFTS and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement, that
is to say :-
My invention, relates to the construction of built up Cranks, being particularly
applicable to Cranks of marine Engines, as by using my invention steam ships are
enabled to carry duplicate parts of such improved Cranks, such duplicate parts
being less cumbersome than an entire or solid Crank, and more easily stowed
away.
The object of my invention is not only to enable steamers to carry duplicate
cranks with greater convenience of stowage, but to construct Cranks in such a
manner that in case of failure, they may be readily taken to pieces, the faulty part
be removed, and a duplicate be substituted with a minimum amount of labour; the
repaired crank when properly put together being perfectly rigid and trustworthy.
And in order that my invention may be clearly understood, I have annexed a
sheet of drawings representing a Crank made according to my invention, the same
letters of reference indicating similar parts in any of the figures in which they
occur.
Fig. 1, is an elevation of a Crank, shown partly in section, and made after my
invention.
Fig. 2, plan with one cap removed.
Fig. 3, elevation of web showing method of fixing Cap.
Fig. 4, elevation of web showing another method of fixing cap.
In carrying out my invention, I make the Crank pin A and the two webs B, B,
either of one continuous piece of metal, or separately and fit them together as
shown in Fig. 1.
The webs are divided through the openings for the Shafts C, C, at the line D,
the detachable parts forming the Caps F, F.
The Caps and the webs on their joint faces are made with a step either undercut
as at G, and G¹, Fig. 4 or as H and H¹, Fig. 3. and one or more suitable keys I, J,
are used to draw and secure the parts together; and in order that there shall be
no possibility of the keys becoming loose, I make the bolts K, to intersect slightly
the said keys, so that movement is impossible.
When the steps above mentioned are made undercut as in Fig. 4, the caps are
put in position by sliding them over the ends of the shaft sideway, the keys are
then driven in the keyways.
To secure the webs upon the shaft in the exact position required, and to prevent
them turning upon the shaft, I form a half collar L, which may be made either
concentric or eccentric as shown in Figs 3 and 4.
I prefer to make this half collar out of the solid metal of the shaft, and whether
it is made concentric or eccentric it fits into a corresponding recess sunk in the

page_text: inner face of the web, and acts as a key to prevent any movement of the parts
when put together.
I have only described and shown the use of one concentric or eccentric collar
but I wish it to be understood that I may use more than one if found desirable.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
.
The manufacture of Crank Shafts (which term includes the Crank alone with-
out the shafts C, C,) constructed substantially as herein before described and as
illustrated.