Improvements relating to the Construction of Cranks, Crank-shafts, and other Shafts or Axles, which Improvements are Partly; Applicable for the Securing of Ships' Propellers on their Shafts and for similar Purposes.
Year: 1887

page_text: Date of Application, 25th Oct., 1887.
Complete Specification Left, 16th July, 1888
Complete Specification Accepted, 31st Aug., 1888
Improvements relating to the Construction of Cranks, Crank-shafts,
and other Shafts or Axles, which Improvements are Partly;
Applicable for the Securing of Ships' Propellers on their Shafts
and for similar Purposes.
I, MANASSAH GLEDHILL, Director of Sir Joseph Whitworth & Co. Limited, of
Openshaw, Manchester, in the County of Lancaster, Engineers do hereby declare
the nature of this invention to be as follows:-
My invention relates partly to "built up" cranks and crank-shafts, that is to say,
cranks or crank-shafts which are constructed of separate pieces fitted accurately and
secured together by means of keys or other devices. It also relates to the construction
of other shafts or axles. The said invention, moreover, affords the means for securing
a ship's propeller upon its shaft without weakening the said shaft or propeller as in
the ordinary method of keying the propeller in its place. The said invention further
provides for securing together in a strong and durable manner other parts and devices
fitted one upon another, for instance, in cases where a rotating shaft or axle has to
carry any part which has to be made fast thereon.
The said invention is based chiefly upon the principle of uniting the parts by means
of numerous shallow grooves and projections so that neither part will be weakened by
having therein a deep groove or incision, which is, in all cases, an element of weakness
and is especially so in the case of a propeller-shaft, as, by reducing the area of the
metal in the part where the resistance to torsional stress should be most effective,
it very materially diminishes the strength of the shaft.
In the construction of cranks or crank-shafts, say for example, a double crank for a
steam-engine, I form the various parts, viz. :-the shaft, the arms or webs.and the
crank-pin separately.
Each part of the shaft has its end, which is to receive the crank-arm or web,
larger in diameter than its other portion, and, in this enlarged portion of the shaft, I
form; by planing or otherwise, a series of shallow longitudinal grooves and projections;

page_text: and I form in the hole of the crank-arm or web similar grooves and projections which
are accurately fitted to and arranged to engage with those on the shaft, so that, when
the arm or web is properly placed on the shaft, the two parts will be united in a very
strong and durable manner without weakening either part by the formation therein
of the deep key-ways or grooves which are necessary in the ordinary method of
keying the parts together.
In some instances, I form the arm of the crank with a counterbalancing extension
and divide or split the said extension from the hole to its outer extremity so
that the arm can be easily fitted upon the end of the shaft. Then, by means of screw-
bolts passed through the said extension and provided with suitable nuts, the two sides
of the divided part are united to secure the arm upon the shaft. To facilitate the
cramping together of the two parts of this divided extension, I prefer to use a
hydraulic or other compresser before tightening the nuts upon their bolts.
In the construction of a hollow crank-shaft according to my invention, I build up
the said shaft with two or more tubes fitted, one within another. The outer tube has
the end portions of its bore formed with shallow longitudinal grooves and projections,
and the adjacent inner tube has its end portions formed with projections and grooves
accurately corresponding with those of the outer tube, so that, when the inner tube is
properly inserted and adjusted within the outer tube, the two tubes will be very
securely and solidly united. In like manner, if necessary or desirable, a third tube
may be inserted in and united with the second of the above named tubes. This part
of my invention is applicable in the construction of straight shafts or axles.
The crank-pin is also, in some instances, made hollow and formed of two or more
tubes placed one within the other.
My improved method of construction ensures great flexibility of the parts.
In applying my invention to a ship's propeller, I form on the end of the shaft an
enlarged cylindrical or taper portion provided with shallow longitudinal ribs, keys or
projections, and, in the hub or boss of the propeller, I form a corresponding number
of grooves of similar depth accurately fitted to the keys or projections on the shaft so
that each of the said keys or projections will enter a corresponding groove in the
propeller-hub and the entire series of grooves and projections will present a very large
area of surface to resist the torsional stress, without weakening the shaft and propeller
as in the case where a single deep key and groove are used..
I also apply my invention for securing couplings or coupling boxes on the ends of
shafting and for similar purposes.
Dated th: Ozil L
1
1007
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Improvements relating to the Construction of Cranks, Crank-shafts,
and other Shafts or Axles, which Improvements are Partly
Applicable for the Securing of Ships' Propellers on their Shafts
and for similar Purposes.
I, MANASSAH GLEDHILL, Director of Sir Joseph Whitworth & Co., Limited,, of
Openshaw, Manchester, in the County of Lancaster, Engineers, do hereby declare
the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
My invention relates partly to "built-up" cranks and crank-shafts, that is to say;
cranks or crank-shafts which are constructed of separate picces fitted accurately and
secured together. It also relates to the construction of other shafts or axles. The
said invention, moreover, affords the means for securing a ship's propeller upon its
shaft without weakening the said shaft or propeller by the formation therein of deep
grooves or incisions as in the ordinary method of keying the propeller in its place.
The said invention further provides for securing together in a strong and durable
manner other parts or pieces fitted one upon another; for example, a wheel or other
object, on a rotative shaft or axle.
The said invention is based chiefly upon the principle of uniting the separate parts
by means of low, shallow or superficial ribs or projections formed solidly or integrally
with each part and fitted in shallow grooves or channels in the other part, so that
neither part will have therein a deep groove or incision, which is, in all cases, an
element of danger, as it reduces the area and interrupts the continuity of the fibrous
structure of the metal in the part where the resistance to torsional stress should be
most effective, and thereby very materially diminishes the strength of the shaft,
such diminution of strength being particularly objectionable in the case of a
propeller-shaft.
In the accompanying drawings
Figure 1 is a sectional side elevation of a double crank constructed in accordance
with my said invention.
Figure 2 is an end elevation of the said crank.
Figure 3 is a sectional side elevation, and
Figure 4 an end elevation illustrating another form or modification of the
said crank.
Figure 5 is a side elevation, partly in vertical longitudinal central section.
Figure 6 a transverse section on the line x, x, Figure 5, and
Figure 7 a rear end elevation, illustrating my improvements applied to a
propeller-shaft.
Like letters indicate corresponding parts throughout the drawings.

page_text: aby
In the construction of a double-crank, say for a steam-engine, I form the various
parts, viz. the shaft a, the arms or webs and the crank-pin e separately. Each
part of the shaft preferably has its end a¹, which is to receive the crank-arm or
web b, larger in diameter than its other portion. In this enlarged portion a' of the
shaft I form, by planing or otherwise, a series of shallow longitudinal grooves and
projections, and I form in the hole of the crank-arm or web b corresponding projections
and grooves which are accurately and closely or tightly fitted to, and arranged to
engage with those on the shaft a, as shown at a², a³. Therefore when the said arm or
web is properly placed on the shaft, the two parts will be united in a very strong and
durable manner without weakening either part by the formation therein of the deep
keyways or, grooves which are necessary, in the ordinary method of keying the parts
together.
:. 7
In some instances, I form each arm or web of the crank with a counter-
balancing extension and divide or split the said extension from the shaft-hole to its
outer extremity, so that the arm can be easily placed upon the end of the shaft.
Then, by means of screw-bolts 62 passed through the said extension and provided with
nuts b³, the two-sides of the divided part or extension can be cramped together to
firmly secure the arm upon the shaft. To facilitate the cramping together of the two
parts of this divided extension of the arm, I prefer to subject them to the action of a
hydraulic or other powerful compressor and thereby bring theni properly together
before tightening the nuts 63 upon their bolts.
In the crank shown in Figures 1 and 2, the nuts 63 are made conical and are fitted
in corresponding conical recesses in the arm b', and the said nuts are slit radially for
a portion of their length to permit the application of a suitable key or wrench for
screwing then upon or unscrewing them from the bolts 6. When the said nuts are
tightened to cramp together the two parts of the divided extension, they will be forced
into the conical recesses in the said extension thus obviating or diminishing the liability
to accidental slackening of the said nuts.
In the construction of a hollow crank-shaft according to my invention, I.build up
the said shaft of two or more tubes fitted one within the other as at at, a. The outer
tube a has the end portions of its bore formed with shallow longitudinal grooves and
projections, and the adjacent inner tube at has its end portions formed with projections
and grooves accurately corresponding with those of the outer tube. These grooves
and projections are fitted together as shown at a, a', so that, when the inner tube is
properly inserted and adjusted within the outer tube, the two tubes will be very
securely united. In like manner, if necessary or desirable, a third tube may be
inserted in-and united with the inner tube. This part of my invention is applicable
in the construction of shafts or axles which are straight throughout their length.
The crank-pin c is also, in some instances, made hollow and formed of two or more
tubes placed one within the other as at c', c².
.
My improved method of construction ensures great flexibility of the cranks and
shafts or axles, thereby rendering them more capable than those constructed in the
ordinary manner of withstanding or resisting the stresses to which they are
subjected in use.
For securing a ship's propeller in place on its shaft according to my said invention,
I form on the end of the shaft d (Figures 5, 6 and 7) an enlarged portion d', which
may be either parallel or taper, and which is provided with shallow longitudinal ribs
or projections ; and in the hub or boss e of the propeller, I form a corresponding
number of grooves of similar depth and width accurately fitted to the ribs or pro-
jections on the shaft, so that each of the said ribs or projections will enter a
corresponding groove in the propeller-hub. The latter is driven upon the shaft so
that it tightly fits the said shaft and the said ribs or projections tightly fit the grooves
in the propeller-hub or boss. The entire series of projections will increase the
resistance to the torsional and shearing stresses, instead of weakening the shaft and
propeller as in cases where separate keys inserted in deep grooves or keyways are used.
Moreover by uniting the parts according to my invention as above described, the
liability to fracture of the shaft commencing at the bottom or ends of the groove or

page_text: keyway and the tendency to splitting of the propeller-boss while being driven tightly
upon its shaft are avoided or diminished.
In some instances, instead of making the shaft with an enlarged portion as above
described, I make the top or outer surface of the keys or projections flush with the
surface of the shaft.
I also apply my invention for securing couplings or coupling-boxes, pulleys or
wheels on shafting, and for similar purposes. In Figuros 5 and 6, 3 is a part of a
coupling which is secured on the shaft, substantially in the manner above described
with reference to the ship's propeller by means of grooves and projections at d*. I
prefer that the couplings should be warmed before being placed upon the shaft and
should be shrunk thereon.
I do not limit myself to any particular or specific number of projections and grooves
in the shaft and in the propeller or other object fixed thereon. The number shown in
the drawing or about that number will be advantageous in many cases; but in other
cases I can use a greater or a lesser number to make the required connection between
the two parts.
In some instances, I make the inner and outer tubes of a shaft or axle of different
qualities of metal. For example I make the inner tube or tubes of metal not so hard
as that of the outer tube or vice versa. The inner tube is not liable to be injured by
repeated heating and cooling or expansion and contraction. It may therefore be
made of very strong and hard metal. If the outer tube be made of softer metal it will
not be so liable to crack, and should a crack commence in the said outer tube it will
not necessarily extend to the inner tube.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I wish it understood that I claim :-
First. A built-up crank the parts of which are united by means of shallow grooves
and projections, substantially as, and for the purpose, set forth.
Second. The improved built-up crank having the parts united by means of the
grooves and projections and having the webs provided with the divided or split
extensions, substantially as described with reference to Figures 1 and 2, or to Figures 3
and 4 of the drawings, for the purposes above specified.
Third. A shaft or axle consisting of two or more tubes placed one over another and
united by means of shallow grooves and projections, substantially as, and for the
purpose, set forth.
Fourth. The above described method of providing for securing a ship's propeller-
boss, a wheel or other object upon a shaft or axle by the use of shallow keys or
projections formed solidly or integrally with the one part and to accurately fit grooves
in the other part.
Fifth. A propeller, wheel or other object combined with and securely fixed upon a
shaft or axle substantially as described, without the use of separately formed keys or
wedges inserted in grooves or keyways.