Universal Joint Coupling for Revolving Shafts.
Year: 1889

page_text: OMPLETE SPECIFICATION.
[Communicated from abroad by REINHARD MANNESMANN, of Remscheid, Blieding-
hausen, in the Empire of Germany, Engineer.]
Universal Joint Coupling for Revolving Shafts.
I, OLIVER IMRAY of No. 28 Southampton Buildings Chancery Lane in the County
of London Fellow of the Institute of Patent Agents 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 to a coupling for revolving shafts which is a modification of
the well known "Universal joint" or "Hooks coupling" and which combines the
advantages of ready adjustment of the latter to angular positions of the shafts, with
the strength and safety of the clutch or claw coupling, so as to render it particularly
applicable for the transmission of considerable motive power, such as occur in driving
gear for rolling mills. The most important peculiarities of these improved couplings
are best demonstrated by shewing how they are derived from the ordinary form of
universal joint, for which purpose I will refer to the accompanying drawings.
In constructing the ordinary universal joint shewn diagrammatically at Fig. 1, there
is usually a cross piece 6 having trunnions 2, 2, 3, 3, fitting the eyes a a and c c of the
two forks of the couplings as shewn at Fig. 2.
If now the central part of the cross piece b be removed, leaving the four separate
trunnions 2, 2, 3, 3, and if furthermore these together with the eyes a, a, c, c, be bisected
by two planes X X and Y Y, and the one half of each of these parts be removed
(namely that half represented by the singly hatched portion of the eyes) while the
other halves of the eyes which are cross-hatched be extended so as to form quadrant-
shaped sectors embracing on the one side the semicircular surface and flat ends of the
semicylindrical trunnions 2, 2 and 3 3, and on the other side fitting with flat
surfaces 21; 31, against the flat surface of the half trunnion embraced by the contiguous
sector, as shewn at Fig. 3, the form is arrived at shewn at Fig. 4. The parts a and c
are similar to the two parts of a clutch or claw coupling with two teeth, but having
inserted between them the four semicylindrical trunnions b¹ a b¹ c.
The nature of the motion transmitted by this coupling will be the same as that of an
ordinary universal joint, when the axial lines of the shafts of which the sectors a a
and c c form part are made to assume varying angles with each other; the sectors a a
in displacing the half trunnions b'a b' a, will cause these to slide with their flat faces
against the flat meeting faces of c c and at the same time to turn somewhat in their
cylindrical bearing surfaces, while the sectors cc in displacing the half trunnions b¹ eb¹ c
will cause them to slide on the flat faces of a a and also to turn in their bearing
surfaces.
It will be evident that the conditions will remain the same if, in place of the semi-
cylindrical trunnions and their correspondingly formed seats, are substituted other
semi bodies of revolution such as hemispheres 6' or semicones 6 as shewn at Fig. 5,
and if furthermore the flat surfaces of these bodies have projections such as 32 formed
upon them, as shewn at Fig. 6, which fit into correspondingly formed grooves 3* in
the flat faces of the sectors' against which they work, as shewn at Fig. 7, these grooves
being of such a curved shape, as shewn, as to allow of the required angular displace-
ment of the two shafts, in turning respectively on the axes X X and Y Y. This con-
struction will have the advantage of preventing the longitudinal displacement of the
two shafts in the same manner as in the original universal joint.
The use of hemispherical trunnions 61 Fig. 5 would offer the advantage that these
would tend to turn continuously in one or other direction in their sockets, thus
insuring a uniform wear of the rubbing surfaces, such motion being the greater, the
greater the angle formed by the two shafts is.

page_text: If the sectors or claws c c Fig. 4 belong to the driving shaft, then it will be evident
that only the trunnions b' a are in operation, while those 6'c only serve for preventing
back-lash, and consequently these may be made of smaller dimensions, as at Fig. 8, or
they may be entirely omitted as at Fig. 9, if suitable bearing surfaces ss be provided
for preventing any relative motion of the two parts of the coupling in the direction of
the axes X X and Y Y.
These surfaces must, in view of the required variation of the angular position of the
two shafts, be so formed that, for example, the projections on the claw a Fig. 10
must be of angular form with the apex coinciding with the axis Y Y and working
against a flat surface on the part c, while on the other hand the angular bearing
surfaces of the part e must coincide with the axis X X and must work against flat
surfaces sa of the part a. For the said angular form may be substituted a slightly
rounded form of the edge, if a certain moveability of the coupling is desired.
It will also be seen that the distance of the semitrunnions from the centre of the
coupling is optional, and consequently such distance may be different for the several
trunnions.
In all cases the coupling will be self supporting and consequently will only require
the one part to be carried in a bearing.
The two other trunnions, or at any rate one of them, can also be inade with sharp or
rounded edges. If the parts of the coupling are to be shiftable in any axial direction
relatively to each other, it is advisable to arrange the trunnions symmetrically to the
axes X and Y Fig. 16, which are at an angle of 45° to the axes X and Y.
This coupling may be supposed to be derived from the double universal joint shewn
diagrammatically at Fig. 11. To the shafts 1 and 6 are respectively fixed doublė
forks a, a and c c¹ the planes of which are right angles to each other. The outer
forks a and c are connected by a ring shaped piece 6 with trunnions 2 and 5, while
the inner forks a¹ c² are connected by a cross shaped piece with trunnions 3 and 4.
The axes of the trunnions 2 coincide with those of the trunnions 4, and those of 5
with those of 3, when the axes 1 and are in line.
Such a double coupling requires to have some play in all its bearings, to enable it to
revolve when the axes 1 and 6 are at an angle to each other. In revolving, an alternate
working of the several trunnions will take place so that only one half thereof will be
in action.
With the modified couplings having only semitrunnions on the other hand the one
cross connection serves for driving while the other serves to prevent backlash. There
is here no separation of the pressing surfaces from those receiving the pressure; any
escape of oil in consequence of looseness of the trunnions in their bearings is conse
quently prevented.
It is also in this case necessary to give both the cross connections some play in the
bearings to allow of the rotation of the coupling when the axes are at an angle.
Figs. 12, 13 and 14 shew in three views at right angles to each other, the practical
construction of the coupling at Fig. 11. The part a has four arms of which those
diametrically opposite each other lying in the direction of axis Y are connected to the
trunnions 2 of the cross piece 6' while the two others are connected to the trunnions 3
of the part 6. The cross piece 62 is of a bar shape having at its middle a disc shaped
enlargement the periphery of which forms the trunnion 5 Fig. 14, by means of which
this piece is embraced by the part c of the coupling; the cross piece 6' on the other
hand embraces the disc shaped trunnion 4 of the part c Figs. 13 and 14.
It will be seen on comparison with Fig. 11 that the trunnions 2 and 4 lie in the
Y axis and the trunnions 3 and 5 in the X axis when the geometrical axes of the
shafts 1 and 6 are in line with each other. If however these shafts assume an angular
position, the trunnions assume different positions, as shewn at Fig. 11.
This coupling can be transformed in precisely the same manner as described with
reference to the coupling at Fig. 2, as shewn at Fig. 15, the parts a and c being
extended so that of the four trunnions 2 and 3 only the semi trunnions b'a and bª a
remain, which bear with their surfaces $5 and 4 corresponding to the trunnions 5
and 4 against the parts o as at Fig. 16.

page_text: It will be readily seen that the notion of this coupling is identical with that of the
coupling Fig. 11, as if the half couplings are turned relatively to each other round the
X axis, the truonions & a Fig. 16, which correspond to the cross piece Fig. 11, will
remain stationary and the trunnions 3a which correspond to the cross piece 6' turn
in their bearing surfaces 3. Consequently the surfaces 3 Fig. 16 will turn relatively
and 51 relatively to c, as the trunnions 3 and 5 Fig. 11 turn relatively to a and c;
on the other hand the surfaces 2 Fig. 16 will remain stationary relatively to a, and 41
relatively to c as the trunnions 2 and Fig. 11.
to
a,
The converse will take place if a and c are turned on the axis Y.
From this it will be evident that by the described transformation of the
conpling no parts thereof are done away but that they receive a different form. As in
the previous case the surfaces 2 and 3 of the trunnions 62 a and b a can be surfaces
of revolution of any kind, according to the X and Y axes, and the surfaces 4¹ 51 can
also be surfaces of revolution according to the X and Y axes, instead of plane
surfaces.
If the part c drives, then on rotation taking place in the direction of the arrow I
Fig. 16, the trunnions 6a will transmit the power, and if in the direction of the
arrow II the trunnions 63 a. If for the rotation in the direction of II only a smaller
force is required the trunnions & a can be made smaller than the others, as at
Fig. 17.
For the correct action of the coupling it is necessary with the first construction
Figs. 4 to 10, that the point of intersection of the axes of the two shafts shall always
be the same, while with the second construction Figs. 16 and 17 this is not necessary,
as the coupling.trunnions are in this case all carried by the same part. This is clearly
shewn by Figs. 18 and 19 which are developments of the two couplings; if in Fig. 18
the two parts of the coupling a and c are shifted relatively to each other, as shown in
dotted lines, the centres of the semitruunions b¹ a b¹ c will not remain in one and the
same straight line. This coupling will therefore operate the less effectively the more
the parts a and c are moved apart.
On separating the parts a and c at Fig. 19 on the other hand, the relative positions
of the semi-trunnions b' a b a are not altered.
On the other hand the construction Fig. 18 will allow of a greater angle being
formed by the two shafts than is the case with the construction Fig. 19; in the latter
case, on the two parts assuming an angular position, there will be a jamming action
between the trunnions and the part c as the distance of the centres of 6 a b a with
reference to a will remain the same while the distance between the faces 4 and 5¹ of c
varies; in Fig. 18 on the other hand a jamming will take place in respect of the one
trunnion while a loosening will take place with regard to the other, so that there is
a compensating action affording a practically close contact.
From the above it will be seen that the second construction of coupling is only
suited for slightly angular positions of the shafts, but will allow of longitudinal
shifting, while the first construction will allow of a greater angle but will not permit
of longitudinal shifting.
For the above purpose both half couplings may be made with suitable projections,
such as a point on the one and a recess on the other as at Fig. 20, or a hemisphere
and corresponding socket as at Fig. 21 or two points as at Fig. 22.
The above described constructions of couplings are preferably made with two claws
to each part, as described, but, in particular for the transmission of small power, more
than two claws may be employed, the increased number tending to afford a more
uniform transmission of the motion.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
--
1. A universal joint coupling formed of a clutch or claw coupling with two or more
claws having introduced between the driving and driven surfaces of the respective

page_text: such as bb, ba, b¹ c. or b³ a, b a which are either carried in bearing surfaces of the
claws of the one part of the coupling only, or partly in the one and partly in the other
part, substantially as herein described.
2. In universal joint couplings such as are referred to in the preceding claim, the
introduction of bodies of revolution or trunnions, such as b'c Fig. 8 or a Fig. 17.
between the parts of the claws which have to transmit the power on reversing the
motion, for preventing backlash and to enable the coupling to drive in both directions
and to be self supporting.
Dated this 7th dow of Tone 1800
ABEL & IMRAY,
Agents for the Applicant.