AN IMPROVED SHAFT COUPLING
Year: 1869

page_text: LETTERS PATENT to. Melville Clemens, of Boston, in the County of
Suffolk, and State of Massachusetts, of the United States of America,
T
COMPLETE SPECIFICATION filed by the said Melville Clemens at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 28th October 1869, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MELVILLE
CLEMENS, of Boston, in the County of Suffolk, and State of Massa-
chusetts, of the United States of America, send greeting..
WHEREAS I am in possession of an Invention for "AN IMPROVED
SHAFT COUPLING," and have petitioned Her Majesty to grant unto me, my
executors, administrators, and assigns, Her Royal Letters Patent for the
same, and have made solemn Declaration that I am the true and first
Inventor thereof.

page_text: NOW KNOW YE that I, the said Melville Clemens, do hereby declare
that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and in
what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Drawing, of which
Figure 1 is a side elevation of the device shown coupling together a
vertical and a horizontal shaft. Figure 2 is a similar side elevation of
the same when the connected shafts are revolved on their axes one-
fourth of a revolution from the position shown in Figure 1. Figure 3
is an inside plan view of the pivoted crank arms of the vertical shaft.
Figure 4 shows a mode of constructing the pivoted crank arms so that
they shall counterbalance each other on their shafts. The dotted
diagram lines on the Figures are employed to illustrate mechanical
features of construction and operation of the device.
The nature of the said Invention consists chiefly in connecting any
two revolving shafts together for propelling machinery by means of one
or more pairs of crank arms, which are attached at their inner ends to
the connected ends of the shafts by a pivoted connection thereto, and
which are pivoted together at their outer ends in such a manner sub-
stantially as herein-after set forth as to enable thereby the transmission
of equal and uniform rotary power and motion from one shaft to the
other, whether the said shafts are set in line with each other or set in
lines diverging from each other.
a and b in the Drawings denote two revolving shafts for communi-
cating motion to machinery, the shaft a being vertical and the shaft b
horizontal, so that the two diverge 90°. The inner end of the shaft a
is secured concentrically to a hub c, which revolves in and is supported
by a journal box d, which is secured to a supporting plate g. The
shaft 6 is similarly secured to a hub e revolving in and supported by a
journal box f which is secured to the plate g. h and i are two pivoted
crank arms of equal lengths whose inner ends are forked, as shown in
Figure 3, and pivoted on a pivot pin j, which is fixed centrally in the
end of the hub c and is at right angles to it. k and I are two similar and
similarly pivoted crank arms, they being pivoted to the hub e by the pivot
pin m. As shown in Figure 3 the centre line n, o, of the pivot pin jis at
right angles to the line p, q, which is the centre line of the crank arms h
and i. The two crank arms and i of the shaft a are joined at their
outer ends to the two crank arms k and of the shaft 6 by ball-and-

page_text: socket joints whose centres are respectively at the points of intersection
of the centre lines of the crank arms so joined together, the crank arm h
being connected by its ball r to the crank arm k by its socket box 8, and
the crank arm i being similarly connected by its ball t to the crank
arm by its socket box u. The ball-and-socket joints 7, 8, and t, u, are
properly crank wrists connecting the crank arms together in pairs by
universal pivot connection, and they are the points at which motion
and power are transmitted from the appendages of one shaft to the
appendages of the other shaft. Each of the pair of crank arms h and k
are of exactly equal lengths, measured in a straight line drawn
from the centre point of their ball-and-socket joint to the centrė
points of their inner end pivot pins, and similarly each of the pair of
crank arms and are of exactly equal lengths, thus the line v, w,
is the length of the crank arm h, and the equal line v, x, is the length
of the crank arm k, and similarly the line y, w, is the length of the
crank arm i, and the equal line y, x, is the length of the crank
arm l.
To aid in describing the principles of construction and operation of
the device referonce will now be made to the diagram lines on the
Figures.
2, a', is the axis line of the shaft a, and b', c', is the axis line of the
shaft b, and d is the point of their intersection. e, f, is a line
bisecting the angle of intersection of the axis line z, a¹, and 6', c', and
it is at an angle of 45° to each of them. The centre points to and x of
the pivot pins and m are at equal distances from the intersection
point d'. The line g', h', passing through the pivot points wand x is
at right angles to the line e', f', and is their point of intersection.
The line v, w, (representing the crank arm h) is at an angle of 221°
from a right angle line to the axis of the shaft a, and the line v, x, of
the crank arm k is similarly at an angle of 22° from a right angle line
to the axis of the shaft b, so that the angle of intersection of the crank
arm lines o, w, and o, x, is 45°. The line y, w, of the crank arm & is
at an angle of 22° with the axis line of the shaft a, and the line y, x,
of the crank arm is similarly at an angle of 22° with the axis line of
the shaft b, so that the angle of intersection of the crank arm lines y, w,
and y, x, is 45°. j, j, is a circle whose centre is at the intersection
point, and whose radius is the line i, v, or , y, the line v, y, being
its diameter. This circle represents a perfect sphere, in whose circum-

page_text: ference (and in a plane of which the line v, y, is the horizontal
projection) the centre pivot points of the ball-and-socket joints r, s, and
t, u, will always move when the driving shaft of the shafts a and b is
revolved. This plane of circular movement of these centre pivot points
is midway between and crosses at an anglo of 45° and at their inter-
secting line the planes of rotation of the pivot pins j and m of the
shafts a and b.
Figure 1 shows the shafts a and b and the crank arms in one position
of a revolution, and Figure 2 shows the same in a position one-fourth of
a revolution of them from the position shown in Figure 1. The crank
arms h and k in the position shown in Figure 2 being respectively partly
horizontally opposite to the crank arms i and I are not wholly shown in
that Figure of the Drawing. When the shafts a and bare revolved to a
position of one-half of a revolution of them from the position shown in
Figure 1 the crank arms h and i will have exchanged positions with
each other, and simultaneously the crank arms and will also have
exchanged positions with each other. Similarly when the shafts a
and 6 are revolved one-half of a revolution from the position shown in
Figure 2 the crank arms h and i will have exchanged positions witli
each other, and in the same time the crank arms k and will have
exchanged positions with each other. In the position of the crank arms
shown in Figure 2 the dotted lines m", m", show a vertical section
through the centre of the crank arm i on the line 2, a', and the dotted
lines,, show a horizontal section through the centre of the crank
arm on the line b', c'.
The crank arms change positions relatively to one another and to their
respective shafts by rotary and pivot movements as follows, viz. :-On
revolving the shafts a and b from the position shown in Figure 1 to the
position shown in Figure 2, or one-fourth of a revolution, all the crank
arms will be carried by rotary movements one-fourth of a revolution
around the axes of their respective shafts, and simultaneously each of
the pair of crank arms h and k turns inward on its inner end shaft pivot
an angle of 55°, and at the same time each of the pair of crank arms i
and turns outward on its inner end shaft pivot an angle of 35°, and
simultaneously each crank arm turns on its outer end pivot an angle
of 45°, in a direction of movement at right angles to its just described
direction of inner end pivot movement, and each crank arm simul-
faneously turns on its outer end pivot an angle of 10° in an inward

page_text: direction of movement at right angles to its other just described direction
of outer end pivot movement. On revolving the shafts a and b in
the same described direction one-fourth of a revolution more, thus
making one-half a revolution of the shafts, all the crank arms will be
carried by rotary movements one-fourth of a revolution more about
their shaft axes; and simultaneously the crank arms hand k will
continue their before described inner end pivot movements, and turn an
angle of 35° more on their respective shaft pivots, and at the same
time the crank arms i and will continue their before described inner
end pivot movements, turning an additional angle of 55° on their respec-
tive shaft pivots; and simultaneously cach crank arm makes cqual
and reverse outer end pivot movements from those just before described
of them in the first one-fourth of a revolution of a and b. On revolving
a and b in the same described direction one-half of a revolution more, thus
completing one entire revolution of them, all the crank arms will be
carried by rotary movements one-half of a revolution more about their
shaft axes, and simultaneously they will all take their first-named
position of inner and outer end pivoting (shown in Figure 1) by equal
and reverse inner end pivot movements and equal and similar outer end
pivot movements to those described of them in the first described one:
half revolution of a and b. Both of the described inner and outer end
pivot movements of the crank arms are not oscillating or vibratory pivot
movements in which motion of the crank arms is suspended, and their
inertia required to be overcome at cach termination of the pivot move-
ment, but their described pivot movements are without such impedi-
ments to steady uniform and continuous rotary motion, because they are
produced wholly by the outer ends of the crank arms moving freely and
continuously, as described in a plane of rotation inclined 45° to and
crossing as described the planes of rotary movement in which their inner
ends move continuously and freely. The device, therefore, admits of
high speed and uniform, undisturbed, and continuous rotary motions of
the shafts a and b, and their connecting parts. Equal and uniform
power and motion may be transmitted from one shaft to the other, as
from a to b, at all points of a revolution of them by means of the
described pivoted crank shaft coupler. This is evident without further
analysis of the mechanical principles of construction and action of the
device when it is considered that the shafts a and b and their connecting
parts are adapted as shown and described for free and uninterrupted
movements in their required directions of rotation at all points of a

page_text: revolution of them, and when it is further considered that the described
and shown construction and adaptation of the crank arms is such that
those crank arms which are connected with each other are like and
'equal, and have the same movements and the same mechanical relations
to their respective shafts for transmitting power and motion at all
points of a revolution of them. In order to produce steady rotary move-
ments of the shafts a and b and their connecting parts without
shaking or jarring on their supporting journal boxes d and f, the
crank arms and their appendages on each shaft must be balanced at
all points of a revolution of the shafts a and b. There are various ways
and modes in which this may be done. One way in which each crank
arm and its appendages may be independently balanced at all points of
a revolution and at all positions of the shafts a and b is to extend such
crank arm across its shaft so that it will with its appendages be balanced
on its shaft pivot. The dotted lines and in Figure 1 show such
extension and balancing of the two crank arms h and i. Another way
of balancing the crank arms is to extend each crank arm across its shaft,
so that the centre of gravity of the two parts of the two crank arms
lying on the one side of their shaft shall be at all points of a revolution
the same distance out at right angles from the axis of their shaft as is
the centre of gravity of the two parts of the same two crank arms lying
on the other opposite side of the shaft. Such a way of balancing is
shown in Figure 1, where the centre of gravity of that part of the crank
arm h and the extended part of the crank arm i lying on their side of
the shaft a is the same distance out in a right angle line from the axis of
the shaft a at all points of a revolution of a as is the centre of gravity
of that part of the crank arm i and the extended part of the crank
arm lying on the opposite side of the shaft a. One mode of balancing
the crank arms is to make one crank arm and its appendages balance
the other opposite crank arm and its appendages on the same shaft at
all points of a revolution of the shafts. In the position shown in
Figure 2 they would of themselves balance each other, because they are
alike in construction and have opposite and like relative positions to
their respective shafts; but in the position shown in Figure 1 they
would be out of balance, because they have different relative positions
to their shafts, and their centres of gravity are consequently at unequal
distances from the axis of their shafts. Balancing the crank arms of
each shaft by this described mode of balancing may be done in one way
by proper disposition of weights attached to the crank arms. Figures 1

page_text: and 2 show such use of weights. The weights m' and ' on the crank
arms and i of the shaft a and the weights o¹ and p' on the crank
arms k and I are for that purpose. They are, as shown, adjustable both
longitudinally and at right angles to their respective crank arms, but
they may be adapted for only one of those adjustments or for fixed non-
adjustable attachment to their respective crank arms and accomplish the
same required result of balancing. The weights are similar and equal
and are placed similarly on their arms. at equal distances from their
inner ends, so that when one crank arm is swung further out from its
shaft than the other crank arm on the same shaft the attached weight
of the former is thrown nearer the shaft than is the attached weight of
the latter arm, as shown in Figure 1. In such described use of the
weights it is necessary that in the position shown in Figure 1 the
centre of gravity of the one crank arm and its added weight and its
appendages shall be at a point in a line passing through the centre of
their shaft pivot diagonally opposite to and at the same distance out
from the axis of its shaft as is the centre of gravity of the opposite
crank arm, its weight, and appendages. Thus the centre of gravity of
the crank arm h, its weight m¹, and other appendages when at the
point q' will at all points of a revolution of the shaft a balance the
crank arm i, its weight n', and its other appendages when the centre of
gravity of the latter is at the opposite point 1. Similarly when the
crank arm k, its weight o', and its other appendages have the centre of
their gravity at the point &¹ they will balance as required the crank
arm 7, its weight p', and its other appendages when the centre of gravity
of the latter is at the opposite point . By the same mode of balancing
as last described the crank arms of each shaft may be so constructed
as to balance each other and their appendages at all points of a
revolution of the shafts a and b. Such a way of balancing is shown in
Figure 4, in which the crank arms are shown curved at their inner forked
ends in such a manner that when the outer end of one crank arm of
one shaft is swung further out from its shaft than is the outer end of the
other arm of the same shaft the curved part of the inner end of the
former is nearer the axis of the shaft than is the curved part of the
inner end of the other arm, so that the centre of gravity of the crank
arm and its appendages being at the point v¹, and the centre of gravity
of the crank arm w' and its appendages being at the opposite point x¹
and at the same distance that the point o¹ is from the axis of their
shaft a, they will balance each other at all points of a revolution; and

page_text: similarly the centre of gravity of the crank arm y¹ and its appendages
being at the point z¹, and the centre of gravity of the crank arm a" and
its appendages being at the opposite point 6", they will also balance
each other at all points of a revolution of the shafts a and b.
In Figure 4 is shown a mode of connecting the outer ends of each
pair of crank arms together by pivot pins, which may be used in some
cases in substitution for the described ball-and-socket joint connection of
them. In the outer end of the crank arm 10¹ is secured the pivot pin c
set in the line e', f', centrally with its crank armı. It passes through
the outer end of the crank arm a" connecting it to the crank arm w¹,
and forming a pivot for it to turn on. To admit of both of the before
described outer end pivot movements of the connected crank arms the
pivot pin c must not only be made to turn but also to rock in the end
of the crank arm a", as by enlarged tapering of the pivot hole in a", as
shown by the dotted lines d", which represent a vertical section on the
line z, a', through the centre of the crank arm 10 when the shafts a
and are revolved one-fourth of a revolution from the other position
shown in Figure 4. The crank arms a' and y' are connected together
by the pivot pin g" similarly as described of the crank arms 70 and a".
The shafts a and b may be placed at other angles than at right angles
with each other, and equal and uniform rotary power and motion be
transmitted from one shaft to the other by the described pivoted crank
shaft coupler. To do this and for suitable and convenient adjustments
of the shafts a and b and their connecting parts, so as to be well secured
and supported in their proper relative positions, the supporting plate g is
used, and it is adapted so that the shaft a may be swung as on a pivot
at the point w, and so that the shaft b may also be swung as on a pivot
at the point by means of making the securing bolts ", ", h", ", of
the journal box d pass through and be adjustable in curved slots 211, 211,
in the plate g, and by means of making the securing bolts ", ",", j",
of the journal box f pass through and be adjustable in similar curved
seats", ", in the plate g. In the described adjustments of the shafts
to other angles with each other than a right angle each shaft should be
swung equally towards each other if more than 90° is required to be
turned by them, and from each other if less than 90° is required to be
turned by them. The shafts a and b may be adjusted to different angles
of divergance by swinging one or both of them as on a hinge or pivot
at the intersection point (d) of their axis lines, and when so swung at

page_text: whatever position they occupy equal and uniform rotary motion may be
transmitted from one shaft to the other by the described shaft coupler.
The construction or adjustment of the described pivoted crank shaft
coupler may be if desirable made such that the crank arms of each pair
shall be at greater or less angles with each other and with their shafts
than those shown and described; but in all cases it is necessary that
the crank arms of each pair be of equal lengths, and that they have
respectively the same relative positions to their shafts at all points of a
revolution. Moving the shafts a and b equally and similarly in a
longitudinal direction either inward or outward by adjustable collars or
adjustable journal boxes or otherwise would be such an adjustment of
the device as would make the crank arms of cach pair at greater or less
angles with each other and with their shafts, and the crank arms of each
pair would be of equal lengths and have the same relative positions to
their shafts at all points of a revolution, and when so adjusted the device
could be used to transmit cqual and uniform power and motion from the
one shaft to the other similarly as before described of it. One pair of
crank arms, as hand k or i and 1, may be dispensed with, and equal and.
uniform motion and power be transmitted by the remaining pair from
one shaft to the other; but the described use of the two pairs is most
advantageous, because when both pairs are used the transmission of power
and motion from one shaft to the other, as from a to b, is accomplished
by distribution and action of equal moments of driving force at opposite
points on both sides of the shafts, producing thereby the very important
result of a balanced transmission of rotary force from one shaft to
the other, which is evidently not obtained by the use of only one pair
of crank arms. The supporting plate g is not indispensably necessary,
for the described pivoted crank shaft coupler may be suitably adjusted
and secured in its required position for the purposes described of it by
other means of attachment of supporting journal boxes. The shafts a
and 6 may be secured to their hubs c.and e by any other suitable and
commonly known modes of connection for such purposes. The pivot
pins j and m may be of any other desired form of construction which
adapts them for their described purposes, and they may be connected to
their hubs cand e in various ways commonly known for similar
purposes. They may be made hollow, and be adapted to be filled with
oil and to supply oil to the hubs of the arms turning on them by oil-
feed holes at their end and oil outlet holes leading from the pins to the
hubs, as commonly done in using hollow self-oiling spindles or axles,

page_text: and for the same purpose. The crank arms may be connected in
various ways to their inner end pivots, as by journal boxes of any
commonly known kind adapted to admit of the described inner end pivot
movements and action, and they may be adapted by ways commonly
employed for taking up wear of their frictional surfaces or for adjust-
ments of the inner ends of the crank arms to their described required
positions. The ball-and-socket joints at the outer ends of the crank
arms may be made adjustable in ways commonly known, so as to
enable taking-up wear of their frictional surfaces, or for adjustments of
the outer ends of the crank arms to their described required positions.
The balls may be made hollow to carry oil and to supply it to the socket
boxes as required for self-oiling. The pins which carry the balls may
be screwed through the ends of the arms i and h, and also into the
hollow balls, and have oil feed holes through them leading into the
balls, and the balls may have oil outlet holes in their outer ends leading
into the bottom of the ball sockets. The joints of the socket boxes
being made tight, when the device is in motion centrifugal force will
force oil from the balls into the socket boxes, and will also retain the
oil in the boxes. The oil being fed into the bottom of the boxes will
act to work grit and dust out of the boxes, instead of its working into
the boxes, as is commonly the case in ball-and-socket joint action.
Other modes than those described may be used both of construction
and of connection of the crank arms to their shafts or to each other,
when both the construction and connection of the crank arms adapt
them to produce substantially the same described mechanical action in
transmission of power and motion from the one shaft to the other which
they are employed to connect.
MELVILLE CLEMENS. (L.S.)