IMPROVEMENTS IN TRANSMITTING MOTIVE POWER
Year: 1856

page_text: LETTERS PATENT to James Robertson, of Ardrossan, in the County of
Ayr, North Britain, Engineer, for the Invention of "IMPROVEMENTS IN
TRANSMITTING MOTIVE POWER."
Scaled the 9th September 1856, and dated the 24th March 1856.
PROVISIONAL SPECIFICATION left by the said James Robertson at the
Office of the Commissioners of Patents, with his Petition, ou the
24th March 1850.
I, JAMES ROBERTSON, of Ardrossan, in the County of Ayr, North Britain,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN TRANSMITTING MOTIVE POWER," to be as follows, that is to say:-
This Invention relates to the transmission or communication of motivo
power by the agency of wheels, pulleys, discs, belts, and other rotating appa-
ratus, the acting contact surfaces of which are grooved, recessed, or corrugated,
for the purpose of securing a powerful driving or actuating contact between the
driving and driven details quite independently of the employment of toothed
gearing. The driving apparatus, which is applicable in most situations where
motive power is to be conveyed from one shaft or movement to another, consists
simply of a pair of annularly grooved, recessed, or corrugated pulleys, or
rotating dises, as substitutes for the pair of spur or bevil wheels ordinarily
employed for this purpose; that is to say, the working surfaces of such pulleys

page_text: or discs are formed with encircling annular grooves, recesses, or corrugations
occupying the position and effecting the office of the teeth of wheels, as usually
employed for coupling a driving with a driven shaft. As an example: if it is
intended to apply the Invention for driving the shaft of a screw propeller, the
main shaft of the engine has fast upon it a large driving pulley of a sufficient
breadth on the face to carry the strain passing through it, this face or circum-
ferential area being annularly grooved, recessed, or corrugated instead of being
plain and even, as in a common pulley. The actual transverse section of the
face of the pulley may be varied in many ways, always preserving a species of
serration of greater or less acuteness, pitch, or inclination; that is to say, the
transverse section of the pulley may present external edges with plain even
ridges and furrows of greater or less acuteness of angle; or the inclined surfaces
of such ridges and furrows may be continued only for a short distance from
their apices, and then completed by straight lines in the plane of the pulley or
otherwise; or again, the transverse section may be a regular indulation or
otherwise, presenting in its length, as across the pulley's face, a continuous series
of inclines. The pulley upon the screw propeller shaft has its surface formed
in a precisely similar manner, so that when the two pulleys are geared together
the ridges of one enter the furrows or recesses of the other, and sufficient lateral
connecting pressure is applied to cause the two sets of opposed inclines to have
a good hold or "bite" upon each other. When so arranged, the motion of the
driving pulley is directly transmitted to the driven one in a most efficient
manner, without any jar, noise, or liability to fracture of the working parts.
Such a system of "annular inclined" gearing is applicable for all or most of
the purposes to which toothed gearing is at present applied; and it may also in
some instances supersede the use of belt work. It is particularly applicable
for driving the screw propeller, as well as for the main shafting of mills and
factories, instead of spur or bevil gearing. In adapting such driving apparatus
to the screw propeller the large driving pulley may be formed with an internally
grooved rim as the driving surface, the same shaft having upon it a smaller
externally corrugated pulley. The driven pulley on the propeller shaft is dis-
posed in the space between the internal face of the large pulley's rim and the
external face of the smaller driving pulley on the same shaft. This arrange-
ment will enable the engineer to reverse the screw propeller without reversing
his engines, by bringing either the internal or external corrugations or grooves
into gear, as may be desired.
The small pulley on the propeller shaft is placed with its axis somewhat out
of a vertical line, passing through the axis of the main driving pulley, so that
in action the driven pulley will always have a tendency to roll down the incline

page_text: of the internally grooved rim, and thus ease the strain upon the shaft bearings.
The same system of driving by means of grooved or inclined surfaces is also
applicable directly to belt work, modified so as to secure all the mechanical
advantages of driving by means of large diameters of belt pulleys, whilst the
necessary speed is got up as due to the belt action upon a driven pulley of
small diameter. Instead of passing the endless driving belt upon the small
driven pulley direct, it is made to embrace a loose inflexible metal ring or hoop
of large diameter, which bears directly by its inner surface upon the small
driven pulley. The exterior of the small pulley is grooved, and the inner face
of the ring is grooved to fit it. As the belt passes round it communicates its
driving power to the exterior of the loose ring of large diameter, and the latter
then drives the small pulley within it.
plain or ungrooved surfaces are used.
speed may be obtained by forming the
recess of considerable depth, so that this central portion is of considerably
smaller diameter than that of the two prominent sides or walls of this recess.
The driving belt runs upon the bottom surface of the groove, whilst the
inner surfaces of the two sides of the ring are the actual driving surfaces. The
difference between the diameters of the recessed and elevated parts of the metal
ring thus gives the required increase in the transmitted speed.
This contrivance is also applicable when
By a modification of this plan a higher
loose metal ring with a central annular
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Robertson in the Great Seal Patent Office on the
24th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ROBERTSON, of Ardrossan, in the County of Ayr, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of March, in the year of our
Lord One thousand eight hundred and fifty six, in the nineteenth year of
Iler reign, di, for Herself, er heirs and successors, give and grant
unto me, the said James Robertson, Her special license that I, the said
James Robertson, my executors, administrators, and assigns, or such others
as I, the said James Robertson, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great

page_text: Britain and Ireland, the Channel Islands, and Isle of Man, au Invention for
"IMPROVEMENTS IN TRANSMITTING MOTIVE POWER," upon the condition (amongst
others) that I, the said James Robertson, by an instrument in writing under
my hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said James Robertson, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
My said Invention relates to the transmission or communication of motivo
power by the agency of wheels, pulleys, discs, belts, and other rotating appa-
ratus, the acting contact surfaces of which are grooved, recessed, or corrugated,
for the purpose of securing a powerful driving or actuating contact between the
driving and driven details, quite independently of the employment of toothed
gearing. The driving apparatus, which is applicable in most situations where
motive power
is to be conveyed from one shaft or movement to another, consists
simply of a pair of annularly grooved, recessed, or corrugated pulleys, or
rotating discs, as substitutes for the pair of spur or bevil wheels ordinarily
employed for this purpose; that is to say, the working surfaces of such pulleys
or discs are formed with encircling annular grooves, recesses, or corrugations
occupying the position and effecting the office of the teeth of wheels, as usually
employed for coupling a driving with a driven shaft. As an example: if it is
intended to apply the Invention for driving the shaft of a screw propeller, the
main shaft of the engine has fast upon it a large driving pulley of a sufficient
breadth on the face to carry the strain passing through it; this face or circum-
ferential area being annularly grooved, recessed, or corrugated, instead of being
plain and even, as in a common pulley. The actual transverse section of the
face of the pulley may be varied in many ways, always preserving a species of
serration of greater or less acuteness, pitch, or inclination; that is to say, the
transverse section of the pulley may present external edges with plain even
ridges and furrows of greater or less acuteness of angle; or the inclined surfaces
of such ridges and furrows may be continued only for a short distance from
their apices, and then completed by straight lines in the plane of the pulley or
otherwise; or again, the transverse action may be a regular undulation or
otherwise, presenting in its length, as across the pulley's face, a continuous

page_text: series of inclines. The pulley upon the screw propeller shaft has its surface
formed in a precisely similar manner, so that when the two pulleys are geared
together the ridges of one enter the furrows or recesses of the other, and suffi-
cient lateral connecting pressure is applied to cause the two sets of opposed
inclines to have a good hold or "bite" upon each other. When so arranged,
the motion of the driving pulley is directly transmitted to the driven one in a
most efficient manner, without any jar, noise, or liability to fracture of the
working parts. Such a system of "anuular incline" gearing is applicable for
all or most of the purposes to which toothed gearing is at present applied; and
it may also in some instances supersede the use of belt work. It is particularly
applicable for driving the screw propeller, as well as for the main shafting of
mills and factories, instead of spur or bevil gearing. In adapting such driving
apparatus to the screw propeller the large driving pulley may be formed with
an internally grooved rim as the driving surface, the same shaft having upon it
a smaller externally corrugated pulley. The driven pulley on the propeller
shaft is disposed in the space between the internal face of the large pulley's
rim and the external face of the smaller driving pulley on the same shaft.
This arrangement will enable the engineer to reverse the screw propeller
without reversing his engines, by bringing either the internal or external cor-
rugations or grooves into gear, as may be desired. The small pulley on the
propeller shaft is placed with its axis somewhat out of a vertical line, passing
through the axis of the main driving pulley, so that in action the driven pulley
will always have a tendency to roll down the incline of the internally grooved
rim, and thus case the strain upon the shaft bearings. The same systems of
driving by means of grooved or inclined surfaces is also applicable directly to
belt work, modified so as to secure all the mechanical advantages of driving
by means of large diameters of belt pulleys, whilst the necessary speed is got
up as due to the belt action upon a driven pulley of small diameter. Instead
of passing the endless driving belt upon the small driven pulley direct, it is
made to embrace a loose inflexible metal ring or hoop of large diameter, which
bears directly by its inner surface upon the small driven pulley. The exterior
of the small pulley is grooved, and the inner face of the ring is grooved to fit
it. As the belt passes round it communicates its driving power to the exterior
of the loose ring of large diameter, and the latter then drives the small pulley
within it. This contrivance is also applicable when plain or ungrooved sur-
faces are used. By a modification of this plan a higher speed may be obtained
by forming the loose metal ring with a central annular, recess of considerable
depth, so that this central portion is of considerably smaller diameter than that
of the two prominent sides or walls of this recess. The driving belt runs upon

page_text: the bottom surface of the groove, whilst the inner surfaces of the two sides of
the ring are the actual driving surfaces. The difference between the diameters
of the recessed and elevated parts of the metal ring thus gives the required
increase in the transmitted speed.
And in order that my said Invention may be properly understood, I have
hereunto appended and shall now proceed to describe two Sheets of explana-
tory Drawings, showing some of the many practical applications of which my
Invention is susceptible.
Figure 1, on Sheet 1 of the Drawings, is an end or face elevation, and
Figure 2 is an edge or side elevation, of a pair of wheels, such as may be
employed for imparting a high speed to the shaft of screw propellers. The
large driving wheel A is keyed upon the engine shaft C, and its grooved or
corrugated circumferential surface is in contact with the similarly grooved or
corrugated circumferential surface of the small driven wheel or pinion B, which
is keyed on the propeller shaft D. The shafting is of course made of the same
proportions as ordinary shafting, and the wheels may also be made with the
proportions of ordinary spur gearing as regards their arms and the width and
thickness of their rims, although I do not by any means confine myself to these
proportions. The circumferential driving surfaces of the wheels are grooved
circularly, or serrated or corrugated in transverse section, that is to say, the
surfaces are formed with two or more grooves or hollow lines, of any con-
venient transverse section, provided they present a series of narrow surfaces
inclined in opposite or different directions.
Figure 3, on Sheet 1 of the Drawings, is a Diagram, showing the full size of
the corrugations which are formed upon the surfaces of the wheels represented
in Figures 1 and 2, that is to say, that for wheels such as are represented in
Figures 1 and 2, for driving a screw propeller, the pitch, depth, and width of
the grooves shown in Figure 3 are what I should deem suitable from my
experience so far in the construction and application of my improved gearing,
but at the same time I do not confine myself to the precise proportions shown.
Figures 4, 5, and 6, on Sheet 1 of the Drawings, are full-sized Diagrams,
showing various gradations of grooves, such as are suitable for various sizes of
wheels. It is preferred to remove the apices of the ridges between the grooves,
so that the ridges of one wheel may not reach the bottoms of the grooves of
the other wheel, and so that if any dust or grit gets into the grooves it may lic
in the bottoms without affecting the contact surfaces. The bottoms of the
grooves may also be cut out to a square section, as shown in Figure 6, or they
may be shaped to any other suitable form.
Figure 7, on Sheet 1 of the the Drawings; is a vertical section, and Figure 8

page_text: is an end or face view, of a modified arrangement of my improved gearing, ap-
plicable for driving a screw propeller. Here the driving wheel A is made with
an overhanging rim E, which is grooved on its internal surface, so as to drive
a grooved pinion B placed within it, and fast on the propeller shaft D. By
thus arranging the wheels, the shafts C and D can be brought nearer together,
and if an externally grooved surface F is formed upon the boss of the wheel A,
the shaft D may be reversed by simply shifting the pinion B from the outer
internal surface E to the inner external surface F, and without reversing the
motion of the main or engine shaft C. The facility with which the propeller
may be reversed in this way will be very desirable for screw steamers. A very
slight shift of the pinion B is needed to produce the desired result, and it may
be effected in a variety of ways. In the arrangement shown in Figures 7 and 8
the pressure of steam in a cylinder G is made to lift a lever II, on which are
the bearings I of the end of the shaft D, carrying the pinion B. The steam
acts on a piston, the rod of which is linked to the lever II, and when the steam
is admitted into the cylinder it causes the pinion B to be lifted into gear with
the central external surface F. When the outer internal surface E is required
to drive the pinion B, the steam is allowed to escape from the cylinder G, and
the pinion. descends, and its own weight keeps it in sufficiently close driving
contact with the surface E.
Figure, 9, on Sheet 1 of the Drawings, is a face or end elevation, and
Figure 10 is a plan, of screw propeller wheels, similar to those represented in
Figures 7 and 8, but having a different contrivance for bringing about the
reversal of the pinion's motion. The same letters of reference are used to
indicate corresponding parts in all the four Figures, 7 to 10. The steam
cylinder G is used in the plan shown in Figures 9 and 10, but it is made
double-acting, and acts upon a wedge J, by the transverse movement of which
the pinion B is raised or lowered for effecting the reversal of its motion. The
end of the shaft D carrying the pinion B is carried in bearings K, capable of
sliding vertically in the plummer block L. The wedge J passes through slots
in the sides of the plummer block, and acts on the bottom of the bearings,
.which is inclined. Thus, if the steam piston is moved outwards, it pushes the
wedge under the bearings, and so lifts the pinion into gear with the central
external surface F, whilst on the piston withdrawing the wedge, the bearings
and pinion descend, the weight of the latter causing it to enter into driving
contact with the rim E. In the arrangements shown in Figures 7 to 10 the
speed imparted to the pulley B in one direction is much less than that imparted
in the other direction, the quicker speed being by preference used for pro-

page_text: pelling the ship ahead; but an arrangement is shown in Figures 11 and 12 on
Sheet 1 of the Drawings, for imparting the same speed in both directions
whilst the reversing movement remains the same as in the other arrangements.
In the arrangement shown in Figures 11 and 12, the wheels A and B are
disposed as in Figures 1 and 2, except that the wheel B is made capable of
shifting, by means of either of the contrivances represented in Figures 7 to 10,
or of any other suitable contrivance. Both wheels A and B are encompassed
by a ring M, which is grooved internally, and is always in driving contact with
the wheel A, whilst it is just clear of the pinion B when the latter is in contact
with the wheel A. The motion of the pinion B is reversed by moving it from
the wheel A to the ring M, or vice versa, and as the ring M nierely takes the
place of what is termed a carrier wheel, in ordinary gearing, it imparts to the
pinion B exactly the same speed that the wheel A would itself do, and conse-
quently the speed of the pinion is the same in both directions. The ring M
is kept in position by means of a pair of antifriction rollers N, between which
it revolves.
Figures 13, 14, and 15, on Sheet 1 of the Drawings, aro face or end views
of three pairs of groove-geared wheels, showing different forms of arms.
Figures 10, 17, and 18 are partially sectioned edge views, corresponding to
Figures 13, 14, and 15. In practice it is found that a slight clasticity of the
rims of the wheels with grooved frictional surfaces is very beneficial, as it
relieves the pressure on the bearings and insures a uniform driving contact
between the wheels. To give the desired elasticity to the wheels, the arms are
cast of a bent or undulated form. Thus, in the wheels represented in
Figures 13 and 16, the arms O are undulated, as seen in the sectional edge
view, whilst they are formed with straight edges, as seen in face view. In
Figures 14 and 17 the arms O are curved or bent, as seen in face view, having
straight or flat sides, as seen in the sectional edge view. In Figures 15 and 18
the arms O are undulated, as seen in the face view, having straight sides and
being as broad as the rim, as seen in the sectional edge view.
The Figures on Sheet 1 of the Drawings described so far, represent only
such wheels as correspond to ordinary spur gearing or gearing in which the
shafts are parallel to each other; but my improved grooved surfaces are equally
applicable to Levil gearing, of which an example is shown in sectional edge
view in Figure 19, and in plan in Figure 20. The arms O of the bevil
wheels P, shown in these Figures, are undulated, as seen in the sectional edge
view, having straight sides, as seen in the face view or plan; this forin being
given to obtain elasticy, as already explained. Although I prefer to shape the

page_text: arms in this or any other suitable way, with the view of giving elasticity to the
rim, I do not by any means confine myself to such a shape, either as regards
parallel gearing or bevil gearing.
In Figure 21, on Sheet 1 of the Drawings, is represented in elevation and
edge view a pair of grooved surface bevil wheels, in which the arms are shaped
exactly as in ordinary bevil wheels.
On Sheet 2 of the Drawings hereunto attached, are represented several
further applications of my frictional grooved surfaces, to be used in cases where
motion is to be transmitted or imparted.
In Figures 22 and 23 is shown, in face and edge view, a contrivance to be
substituted for the ordinary rack and pinion, and by means of which rectilinear
motion is derived from rotatory motion, or vice versa. The pinion A is
grooved circularly, in the manner already explained, and the bar B, corre-
sponding to the rack, is grooved longitudinally to fit the grooves of the pinion.
The bar is kept in driving contact with the pulley A, by means of an anti-
friction roller C at the back.
In Figures 24 and 25, on Sheet 2 of the Drawings, is shown in side eleva-
tion and transverse vertical section, an arrangement, in which the frictional
grooved surfaces are employed to impart a reciprocatory rectilinear motion, the
driver revolving continuously in one direction. In this arrangement provision
is also made for the rectilinear motion to be more rapid in one direction than
in the other. The driving wheel A is made with its middle part D of smaller
diameter than its two ends E, the surfaces of both portions being grooved,
according to my Invention. The smaller diameter D is arranged to gear with
a longitudinally grooved bar F, fixed upon the picce to be moved, and the
larger diameter E similarly gear with the grooved sides of a lower bar G, also
attached to the piece to be moved. The parts are arranged so that a very
slight movement puts the pulley A out of gear with one of the bars F, G, and
into gear with the other, and this change is effected at each end of the stroke
of the reciprocating piece. Antifriction rollers H. are applied to the backs of
the bars F, G, to keep them in position. Instead of the bars F, G, moving,
they may be stationary, the wheel A being made by its rotation to move from
end to end. This contrivance may be applied in various machines, such as
planing and other machines.
Figure 26, on Sheet 2 of the Drawings, is a face view, and Figure 27 is an
edge view, of the driving wheel of a ship's windlass, in which the windlass is
turned by what is known as the "patent purchase." The wheel A is formed
with a broad riu B, and is turned by means of frictional holding picces C

page_text: and D, applied to the outer and inner surfaces of the rim. These pieces C, D,
are connected by links set obliquely in such a manner, that when the actuating
rod E is raised, the pieces C, D, grip the rim firmly and cause the wheel to
turn, whilst on the descent of the rod, the hold on the rim is loosened, and the
pieces C, D, slip round to take a fresh hold lower down. This apparatus is
introduced herein to show the application to it of my grooved gearing surfaces,
by which its action is much improved. The external and internal surfaces of
the rim B are grooved, as are also the acting surfaces of the pieces C, D, so
that a greater holding power is obtained, whilst the backward movement of
the pieces is as free and easy as before. The same contrivance may be applied
to the feed motion of sawing and other machines.
Figure 28, on Sheet 2 of the Drawings, is an elevation, and Figure 29 is a
plan, of a pair of locomotive wheels, and portions of rails, showing the appli-
cation of my grooved gearing surfaces for enabling locomotives to ascend steep
inclines. For this purpose a longitudinally grooved rail A is laid along by
the side of the ordinary rail B, as far as the incline extends, and the wheel C
is formed with a grooved rim D, which gears into the grooved rail A, and by
its increased hold prevents the wheel from slipping round, and so greatly
facilitates the ascent of the incline. A similar grooved rail and wheel may be
placed on the other side, but if it is found that the guage of the rails cannot
be adjusted with sufficient nicety to enable the grooves to fit or gear with each
other on both sides, a plain supporting rail E only need be used on one side.
A plain rim F upon the locomotive wheel on that side runs on the rail E, and
the rails A and E are sufficiently high to just lift the wheels off the ordinary
rails B. Or, instead of the plan shewn in these Figures 28 and 29, a raised
grooved rail may be laid along the centre between the ordinary rails, such
rail being acted upon by a small grooved wheel upon the driving axle of the
locomotive.
In Figures 30 and 31, on Sheet 2 of the Drawings, is shown in face or end
elevation and in transverse section, what I term a grooved-surface "speed
ring." In producing great speeds by means of belts, great difficulty is
experienced in making the belt bend properly round a small pulley, and a
very small pulley cannot be used without rapidly injuring the belt, by making
it pass round too shape a curve. This difficulty I get over by introducing a
ring A between the belt B and the pulley C. The outside of this ring is
shaped like an ordinary belt pulley, but its internal surface and the external
surface of the pulley C are grooved to obtain a frictional driving hold. The
belt imparts the motion to the ring, and the ring to the pulley, the last being

page_text: driven as fast as if the belt drove it without any intervening ring, whilst
the belt is all the time passing round the comparatively easy curve of the
ring.
In Figures 32 and 33, on Sheet 2 of the Drawings..is shown in face or end
elevation and in transverse section, a modified arrangement of "speed ring,"
wherein an increase of speed takes place between the belt and the pulley.
This is brought about by shaping the ring A, so that the belt B acts on a
portion of smaller diameter than that of the part or parts of the ring which
act upon the pulley or pulleys C. Two pulleys C are used and are acted upon.
by the outer ends of the ring A, whilst the ring is made of a smaller diameter
between these ends as at D, and the belt B passes round this smaller part.
Figures 34 and 35, on Sheet 2 of the Drawings, are side and end elevations
of an arrangement, showing the application of the intermediate or speed.ring
for casily disconnecting two shafts. The intermediate internally grooved
ring A, is put upon an externally grooved driving pulley B, and the belt C.is
passed round the ring and round the pulley D below, which is to be driven
by it. A curved lever E is arranged to raise the ring A when required,. and
in this manner the ring is lifted off the pulley B, so as not to be driven thereby
when the transmission of the motive power is to be discontinued. At other
times the ring A rests upon the pulley B, and the belt is set in motion, tho
connecting or disconnecting being instantaneously effected by means of the
lever E.
Figures 36 and 37, on Sheet 2 of the. Drawings, are an elevation and a
plan of an arrangement of belt and "speed ring" gearing, for obtaining a high
velocity, where the ring is contrived to keep a short belt in proper. tension.
This arrangement is only applicable to its full extent when the centres of the
driving pulley A, and driven pulley B, are in a horizontal line or nearly so.
The ring C is made very heavy, either by being cast of a massive form, or by
having a pair of fly wheels D cast or fixed upon it, and its weight tending to
bring its centre in a vertical line with the centre of the pulley B, presses down
the lower side of the belt E, and keeps it properly stretched.
I may here remark with reference to the various arrangements of inter-
mediate or speed rings, represented in Figures 30 to 37 on Sheet 2 of the
Drawings hereunto attached, or any obvious modifications of them, that
although I prefer to form them with internal grooved surfaces to act on
pulleys with external grooved surfaces, they may also be made with any other
suitable frictional surface, such, for example, as that obtained by lining them
with leather, one great object in using such rings in connection with belt

page_text: gearing being the outamment of great velocities without passing the belt round
too sharp a curve.
Figure 38, on Sheet 2 of the Drawings, is a face view of a clutch coupling,
with one of the clutch dises partly broken away, and Figure 39 is a sectional
plan, correspondnig to Figure 38. This clutch coupling shews a further appli-
cation of my grooved gearing surfaces, and one of some importance on account
of the very slight movement required for effecting the connection or discon-
nection. In this coupling, two clutch discs A, B, are used, having concentric
annular grooves cut upon their faces, so as to fit accurately into each other.
Both discs A, B, are loose upon the shaft C, the former turning round the shaft
and the latter moving longitudinally upon it, but turning with it, being con-
nected to it by means of a groove and feather D.
The disc A is made with
spur wheel, the arms of
an elongated boss, upon which is keyed a pulley or
which are seen at E. The driving power is imparted to the wheel E and disc
A, but is only imparted to the shaft C when the disc B is in gear with the
disc A, that is to say, when the two are pressed into close contact. The disc B
is formed with an elongated boss, on which are a pair of collars F, and between
these collars is a fork G, by means of which the disc B is shifted into or out
of gear with the disc A. The fork G may be actuated in any convenient
manner, but it is preferred to form it with a turned spindle II, which is inserted
eccentrically in a bush I, capable of turning in a vertical socket J. A lever K
is fitted upon the bush I, and on turning the bush by means of the lever, the
fork G is made by the eccentric action to shift the disc B into or out of gear
with the disc A, by which movement the connection or disconnection of the
apparatus is effected.
Figure 40, on Sheet 2 of the Drawings, is a side elevation of disconnecting
and reversing apparatus, similar to that apparatus represented in Figures 38
and 39. The shaft A carries two loose pulleys A, B, driven in opposite direc-
tions from a first-motion shaft, by means of open and crossed belts. Each
pulley has cast or fixed upon it a grooved dise, similar to the disc A in Figures
38 and 39, and between the pulleys is a clutch piece C, formed with two
discs, so as to be put into gear with one or other of the discs on the pulleys
A, B, accordingly as it is shifted along the shaft in either direction. This
double clutch piece may be shifted in various ways, but in the arrangement
represented in Figure 40 the requisite movement is effected by means of a
fork G carried in an eccentric bush, and moved by means of the lever K,
these details being arranged as in Figures 38 and 39. The clutch piece C is
connected to the shaft by a longitudinal groove and feather, and as the pulleys

page_text: A, B, revolve continuously in opposite directions, it is turned in either direction
accordingly as the cluteli piece is in gear with the disc of either pulley,
whilst if the clutch piece is set midway between the two, no motion will be
imparted to the shaft.
Figure 41, on Sheet 2 of the Drawings, is an end view, and Figure 42 is
a plan, of an arrangement of cones for transmitting different speeds, showing
another application of my grooved frictional gearing surfaces. The concs are
grooved circularly, and motion is transmitted from one to the other through
the intervention of a ring C, formed with grooved external and internal sur-
faces. This ring is placed round one cone, with the surface of which its
internal surface is in contact, and is of such a size and weight as to lie
against the other cone with sufficient pressure to give the requisite driving
hold of the grooved surfaces upon each other. The space between the cones
is sufficiently wide for the ring C to be shifted clear of the two cones, so
that it may be placed at any point along the two cones, accordingly as it is
wanted to increase or diminish the speed of the transmitted motion. It is
considered that the gearing together of the grooves will retain the ring in any
position in which it may be placed, but an adjustable guide may be used for
this purpose if necessary. The ring acts as a carrier wheel between the two
cones, and may be made to encompass both cones if found desirable.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,
First, the application and use of "grooved surface frictional gearing,"
for transmitting or imparting motion, such gearing consisting of parallel,
bevil, or skew wheels or rings, or straight or curved bars, and having curved
or rectilinear surfaces, formed with two or more grooves or hollow lines, in such
a manner as to present in each case a series of surfaces inclined in opposite
or different directions, as herein-before described.
Second, the system or mode of driving screw propellers, wherein grooved-
surface frictional gearing is used for transmitting the motion of the engine
shaft to the propeller shaft, such gearing consisting of wheels or rings, the con-
tact surfaces of which are formed with two or more grooves or hollow lines, in

page_text: such a manner as to present in each case a series of surfaces inclined in oppo-
sito or different directions, as herein-before dereribed.
Third, the application and use, in connection with "grooved-surface frictional
gearing" of a largo size, such as that represented in Figures 7 to 12 on
Sheet 1 of the Drawings hereunto attached, and where the reversing of the
motion is effected by shifting the pinion, as described in reference to the said
Figures, of a steam cylinder and piston for so shifting the said pinion, as herein-
before described.
Fourth, the system or mode of forming the arms of wheels having grooved
frictional gearing surfaces, of a curved, corrugated, or undulated form, as
herein-before described.
Fifth, the system or mode of obtaining a reciprocating motion, which is
quicker in one direction than the other, from a continuously revolving shaft,
by means of a differential grooved surfaco wheel, acting on grooved surface
bars in opposite directions, as herein-before described more particularly in
reference to Figures 24 and 25 on Sheet 2 of the Drawings hereunto
attached.
Sixth, the system or mode of forming the frictional surfaces in what is
commercially known as the "patent purchase" for windlasses, and is also used
as a feed motion for sawing and other machines, with two or more grooves or
hollow lines, presenting in each case a series of surfaces inclined in opposite
directions, as herein-before described more particularly with reference to
Figures 26 and 27 on Sheet 2 of the Drawings hereunto attached.
Seventh, the system or mode of giving the wheels of locomotive engines
increased hold upon the road when ascending inclines, by using rails and
wheels formed on their contact surfaces with two or more grooves or hollow
lines, presenting in each caso a series of surfaces inclined in opposite directions,
as herein-before described more particularly with reference to Figures 28 and
29 on Sheet 2 of the Drawings hereunto attached.
Eighth, the application and use, in connection with belt gearing, of an inter-
mediate ring, round which the belt is passed, and which imparts the motion
transmitted by the belt to a pulley within it, my means of an internal frictional
surface of any suitable kind, acting on the pulley, formed externally in any
suitable way to correspond, as herein-before described more particularly with
reference to Figures 30 to 37 on Sheet 2 of the Drawings hereunto attached.
Ninth, the application and use, in connection with gearing for transmitting
or imparting motion, of clutch couplings composed of discs formed with two
or more annular concentric grooves or hollow lines, presenting in cach case a

page_text: series of surfaces or cones inclined in opposite or different directions, as hercin-
before described more particularly with reference to Figures 38, 39, and 40
on Sheet 2 of the Drawings hereunto attached.
In witness whereof, I, the said James Robertson, have hereunto set my
hand and seal, this Twenty-second day of September, One thousand
eight hundred and fifty-six.
JAMES ROBERTSON. (L.S.)