Improvements in Flexible Couplings for Shafts.
Year: 1890

page_text: Date of Application, 2nd May, 1890-Accepted, 7th June, 1890
Improvements in Flexible Couplings for Shafts.
I, EDWIN HUMAN 8 Delahay Street London S.W. Civil Engineer 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 provides for coupling two shafts for the purpose of transmitting
torsion from one to the other :-
1st. When the shafts are not in the same straight line, but when their axes intersect
at the place where they are to be coupled :
2nd. When their direction is the same, but they are not in the same straight
line and
°
3rd. When they are not in the same straight line, and their axes do not intersect at
the place where they are to be coupled.
The same invention provides for all cases; for the second and third cases are
provided for by duplicating the form of coupling which provides for the first case.
And my invention provides for coupling two shafts, the relative positions or directions
of which can be changed either continuously or intermittently while torsion is transmitted
from one to the other.
I will now describe my invention for providing for the first case. That is to say,
for the case where two shafts are to be coupled for transmission of torsion which do
not lie in the same straight line, and which are to be capable of changing by small
angular dimensions their relative directions; and their axes intersecting at the place
where they are to be coupled. I provide in the adjacent ends of the two shafts, or in
pieces attached thereto, and truly central with their axes, recesses which in shape are
parts of spherical cups: and I provide a sphere, which lies in these two cups and fits
them both; the true centre of the cup belonging to each shaft coinciding with the
true centre of the sphere (which is the point of intersection of the axes of the shafts)
when the shafts are in any of their desired relative positions: and I make these cups
less deep than a hemisphere, and form the faces at the ends of the shafts of a conical
shapo, the apex of the cone coinciding with the centre of the sphere; so that one of
the shafts can assume various angular directions with respect to the other, by allowing
it to turn about any of the axes of the sphere which lie at right angles to the axis of
that shaft.
I provide for attachment, in any suitable manner, to the end of each shaft two
trunnions; the axis of each pair of trunnions is in the same straight line, and at right
angles to that of the shaft to which they are attached: the two trunnions belonging
to each shaft are at equal distance from the axis of their shaft: the axis common to
each pair of trunnions passes through the true centre of the spherical cups described
above as provided at the end of that shaft to which each pair belongs. I provide for
the position of the axis of one pair of trunnions belonging to one shaft, to be at right
angles to the axis of the pair of trunnions belonging to the other shaft; and the
intersection of the axes to coincide with the centre of the sphere described above. I
connect all the trunnions together by means of a ring or rings, suitably formed (or
provided with attachments) to surround them all and fitted to embrace each in such a
way as to leave them free to turn in the ring or rings; and at the same time to
transmit the turning moment or couple through the ring or rings.
The combination of the sphere with its cups, and of the trunnions and ring or rings;
having to one another and to the shafts, the relative positions described above, is what
I include under the name of a "single coupling" in what follows. But in the case
when each pair of trunnions is made a part of their shaft, by such a process as forging
them with, casting them with, or welding them to it; then the portions of the two
shafts at the place where, and in the immediate neighbourhood where, the trunnions

page_text: are thus formed is also included in the assemblage of parts named “ single coupling”
in what follows.
If the angular dimension of the direction of one shaft with respect to the other is
such, as to make it inconvenient to employ one coupling such as is described above
for transmission of torsion; then I employ two or more such single couplings, with
one or more intermediate shafts of convenient length between the ends of the shufts
which are to be coupled.
If, as in the second and third cases set out at the beginning of this specification, two
shafts are to be coupled for transmission of torsion which may live the same direction
but may not be in the same straight line; or which may have different directions but
whose axes do not intersect at the place where they are to be coupled; then I employ
two or more "single couplings," such as I have described above, with one or more
lengths of intermediate shaft between the ends of the two shafts to be coupled. The
sphere, which in the first case lies at the point of intersection of the axes of the two
shafts to be coupled, will in the second and third cases lie at the intersection of each
shaft with the nearest piece of intermediate shaft: and where there are more than two
single couplings" employed, there will be a sphere at the intersection of the axes of
every two intermediate shafts also.
"
"
In order to understand bettor what my invention consists in, I attach hereto
drawings Figs. 1, 2, 3 and 4 which represent methods by which I can effect the
transmission of torsion from one shaft to another and allow of flexibility in their
coupling, substantially as desbribed. Figs. 1, 2 and 3 are different views of a
single coupling" to provide for the first of the cases set out at the beginning of this
specification. The arrangement of the parts shown in the drawings forms a method
of effecting the transmission of torsion under the conditions set out; but I do not
restrict the application of my invention to the particular arrangement or number of
parts shown therein.
Fig. 1 is a section: Fig 2 a side elevation: Fig. 3 an end view of a "single
coupling." S, S, are parts of the ends of the two shafts to be coupled : B is the
sphere lying in recesses formed in pieces A, A, attached to the shafts: T, T, are the
pair of trunnions attached to the shaft S, T, T, are the corresponding pair of
trunnions attached to the shaft S,: R is a ring which surrounds all the trunnions and
embraces each; being provided with blocks bb, in which they can turn, and having
screws and nuts for holding the ring in place on the trunnions.
Fig. 4 is a side elevation of a pair of "single couplings" arranged to provide for
the conditions of the second and third cases set out at the beginning of this specification.
S, S, are parts of the shafts to be coupled: S, is the piece of intermedinte shaft which,
as drawn, has its trunnions formed with it. I do not restrict myself to the exact
arrangement or number of parts as shown in this drawing in applying my invention
as described above.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:
1st. The use of a sphere and spherical shaped cups at the intersection of the axes of
the shafts (whether intermediate or not) to be coupled in order to secure that the
axes of those shafts shall always intersect at that one point (the centre of the sphere)
throughout all positions which the one shaft can take relatively to the other.
2nd. The use of a ring or rings, to surround and embrace the trunnions belonging
to each shaft for transmitting torsion from one shaft to the other; in such a way as
to leave the trunnions free to turn about their axes in such ring or rings.
TAL
EDWIN HUMAN.