Improvements in Composite Driving Shafts.
Year: 1890

page_text: Date of Application, 16th Jan., 1890
Complete Specification Left, 15th Nov., 1890-Accepted. 16th Feb. 1891
PROVISIONAL SPECIFICATION.
Improvements in Composite Driving Shafts.
We, REINHARD MANNESMANN and MAX MANNESMANN, both of Landore,
R.S.O., South Wales, Engineers, do hereby declare the nature of this invention
to be as follows:-
Our invention relates to the manufacture of composite driving shafts which we
effect in the following manner. We place together concentrically a number of iron
or steel tubes, one within another, and either with or without a solid round bar or
core in the centre. These tubes and the central core, when a core is used, are of
such diameters that each can be passed freely, without fitting, into the one outside
of it. The whole is then heated and subjected to rolling pressing or hammering
whereby the tubes are all bound closely together. In order more effectually to
prevent relative displacement of the tubes when the shaft thus formed is subjected
to torsional strain, portions of the circumferences of the tubes may be corrugated or
wires may be coiled on them, so that when the tubes are pressed together the
projections of the corrugated portions or the wires become indented into the metal
of the tubes. Instead of corrugating the tubes, several keys may be inserted in the
spaces between plain tubes, and these are by the pressure caused to indent them-
selves in the metal of the tubes.
Dated this 16th day of Januar 1900
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Composite Driving Shafts.
We, REINHARD MANNESMANN and MAX MANNESMANN, both of Landore,
R.S.O., South Wales, 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 :—
As is well known, propeller and other shafts that are subject to considerable and
sudden strains, are liable to break, and thus frequently cause considerable disasters.
In many cases it is not possible to increase the size of the shaft, and even if it were
possible, such an increase would not always insure the required, safety against
fracture. In such cases it is desirable to impart to a shaft of a certain diameter a
maximum of torsional strength, and also, in the case of propeller shafts to impart to
them a certain degree of elasticity against lateral strains.
The fractures are mostly caused by certain lateral blows or strains exceeding the
elastic limit of the metal.
With an increase of diameter and of weight the intensity of the blows or strains
produced by sudden lateral motion also increases, so that the danger of fracture
remains the same.
According to our present invention we increase the elastic limit of the metal so
as to avoid liability to fracture, by building up the shafts of a series of concen-
trically arranged seamless tubes, which are combined with each other in either of
the following ways for transmitting the torsion from the outer to the inner tubes.
According to one arrangement the tubes are inserted one within the other so as
to leave a space between them, and into these spaces are introduced wires, bars or
bands; or the tubes, before being inserted, are provided with longitudinal ribs or
projections, or, preferably they are formed with helical projections or ribs running
as nearly as practicable at right angles to the direction of the torsional strain.

page_text: The composite shaft thus produced is then heated and is subjected to a rolling
operation in suitable rolls, or is forged or pressed.
By this means the inserted wires bars or bands, or the ribs or projections formed
on the tubes, become imbedded into the contiguous tube and thus form longitudinal
grooves which prevent any turning of the outer tube upon the inner one, so that
the torsional strain to which the former is subjected will be effectually transmitted
to the latter.
The innermost tube of the shaft can be filled out with a solid bar, so as to
produce an apparently solid shaft, or the central space may be left unfilled.
Instead of causing wires, bars, ribs or projections on one tube to be imbedded into
the contiguous one, it will, in some cases, be sufficient to simply place the tubes one
within the other, without such wires, bars &c., and then by a rolling forging or
pressing operation, to shrink the tubes upon each other, thereby connecting them to
the required extent for enabling the torsional strain to be effectually transmitted
from one tube to another..
With the above described method of manufacture, the material of the tubes is
thoroughly worked, so that defects can be at once detected by external and internal
inspection before inserting the tubes, and thus by excluding imperfect tubes, the
production of absolutely perfect shafts can be insured.
If the tubes have been produced by the "oblique rolling" process, the sorting
out of the defective tubes which naturally results from this process already prevents
any defective tubes from being employed, as in that process any crack or other
defect existing in the metal becomes clearly discernable and if such cracks exist to
any considerable extent, the formation of the tube will not be effected.
By working down the tubes to a comparatively small thickness, the material
attains a strength equal to that of rolled sheet metal and a perfectly uniform
texture, while solid shafts, as at present manufactured, are, as is well known, more
dense at the outer surface than in the interior.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. An improved manufacture of composite driving shafts consisting in the
introduction of a series of tubes one within the other and then subjecting them
to a rolling, forging, or pressing operation so as to effect an intimate connection
thereof, substantially as described.
2. In a composite shaft, the combination of a series of tubes placed loosely onc
within the other, with the intervention of wires, bars, bands, and the like, the whole
being secured together by rolling, forging or pressing, substantially as described.
3. In a composite shaft composed of a series of tubes placed one within the other,
preventing any relative motion between the several tubes by causing wires, bars, or
projections situated in the spaces between the tubes to be more or less imbedded in
the surfaces of the tubes by rolling forging or pressing, substantially as described.
Dated this 15th day of November 1890.
ABEL & IMRAY,
Agents for the Applicants.