SUNDRY IMPROVEMENTS IN CARRIAGES (AND SUBSTITUTES FOR WHEELS FOR CARRIAGES) AND OTHER MACHINES
Year: 1814

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LEWIS
GOMPERTZ, of Kennington Oval, in' the County of Surrey, Gentleman, send
greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-seventh day of
April, in the fifty-fourth year of His reign, give and grant unto me, the said
Lewis Gompertz, my exors, adñiors, and assigns, His especial licence, full
power, sole privilege and authority, that I, the said Lewis Gompertz, my
exors, adiiors, and assigns, during the term of years therein mentioned, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies
and Plantations abroad, my Invention of "SUNDRY IMPROVEMENTS IN CARRIAGES
(AND SUBSTITUTES FOR WHEELS FOR CARRIAGES) AND OTHER MACHINES;" in which
said Letters Patent there is contained a proviso obliging me, the said Lewis
Gompertz, by an instrument in writing under my hand and seal, to cause a
particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled in His Majesty's High
Court of Chancery within six calendar months after the date of the said
recited Letters Patent, as in and by the same (relation being thereunto had)
may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Lewis Gompertz, do hereby declare that my said Invention, and the manner
in which the same is to be performed, are particularly described and ascer-

page_text: tained in and by the Drawings. hereunto annexed, and the following descrip-
tion thereof, (that is to say):-
In place of the wheels heretofore used in carriages I apply certain machinery,
which may be denominated scapers, because they escape obstacles, and which
have the property of supporting the carriage at the same distance from the
ground or road, while moving along, and at the same time escaping the friction
of the ground, and having the best chance of escaping the obstacles in the road
also (which otherwise would raise the carriage and load). This is effected by
employing legs or feet to support the carriage when they are beneath it; and
upon them it advances for a certain distance, during which time the feet are
stationary on the ground, till succeeding legs, being brought forward to support
and advance the carriage in turn;--and the legs which which have performed
their office are brought forward to repeat their action. A carriage constructed
on this principle is explained by Fig. 1 and 2, No. 1, of the Drawing hereunto
annexed. The wheels, or substitutes for wheels, each consists of four radii or
'legs revolving on a centre. or axletree in the usual situation, which radii have
a power of extension and contraction in right lines to and from their common
centre; and by means of certain curves (to be hereafter described) they
contract and extend in such a law (during the period that they are in contact
with the road) as to support and advance. the centre always at the same height.
A, Fig. 1; is a square frame revolving on a centre: or axle M; each side of this
'carries a block, a, a, a, a, which supports the joints of a frame or a parallelò-
gram B, B, and C, C; the sides of which are jointed together; as shown in the
Figure, and each carries one of the legs marked .D, V, which in turn support
the carriage, as shewn at Z, Fig. 1, and X, Eig. 2. These: jointed frames, by
opening or shutting on their joints, allow the legs D, V; to advance or recede
from the centre; and the legs have wheels or rollers E, E, attached to them,
'which constantly apply to the curve F, G, H, I, K, which is fixed to the
carriage, and as the whole revolves on the axle M the extension and contraction
of the legs are thereby produced; thus in Fig. 1 the leg D, Z, is at its
greatest contraction, and its wheel E at the highest point of the curve. From
this position, as the carriage advances, the curve.I proceeds to the right of the
Figure upon the wheel E, till it comes to the position of Fig. 2; by which time
the succeeding leg X has reached the ground, and its wheel E comes beneath
the curve to support and advance the carriage; the leg Z, having now become
useless, is gradually lifted off the ground by the turning of .the wheel (or sub-
stitute) guided by the rising in the curve from I to K, and carried round in the
manner shewn by Y upon the circular arch or curve L, L, till it again.comes
to the ground in front to support the carriage; as the parallelograms B, C, are

page_text: not made sufficiently strong to support the carriage when in the inclined
position, as X, Fig. 2, a second wheel N is fixed to each leg, and in the lower
part of its revolution applies itself to an interior curve O, P, P, O, this
curve being so adapted to the other that in all positions of the motion the
5 wheels N and E keep close to them (their respective curves). P, S, S, R, is
a third curve applying to the upper side of the wheel N. The grooves in the
edges of the wheels N and E embrace the edges of their respective curves, and
thus the whole wheel is prevented from lateral deviation from its truc plane of
motion, and for the same purpose the interior curve is continued all round, as
shown at T. A small curve is fixed on the front of the great one, as shown
by the yellow line S, S, and a small roller dotted at t is fixed to the back of the
leg to run on the upper side of this curve, and keep the wheel E close up to
its place. This curve is not essential, but is a precaution against any loose-
ness in the parts. This curve should not be put on the other curve quite flush,
but so that the rims of the wheels in the legs can get between them. The
fect or extremities X, Z, and Y, W, of the legs may be made of any form
adapted to the nature of the ground they are to travel upon, or they may be
furnished with small wheels, as shown in the Figures W, Y, X, Z, which will
allow the carriage to move sideways. If it be thought necessary to employ
larger wheels in the feet it may be done as represented by Fig. 9. Hero D
represents the leg as before; E, the wheel, and Z the foot wheel made of a
larger size, and fixed in an inclined position, so that when the circumference of
the wheel at the bottom is in the centre of the leg, the upper part will be clear
of the edge of the wheel E. are small cups of copper plate to prevent dirt falling
into the parts from the feet when in the position W. The curves F, K, &c., are
supported, as shown in Fig. 1 & 2, by brackets or stays p, extending down
from the bed of the carriage, and these support the weight. To make the
legs tend to the centre in extending and contracting, the two sides B, B, of
each parallelogram are provided with small toothed racks working together, as
shown at c, e, Fig. 2, which cause both sides to make the same angle with the
side of the square frame A. A similar pair of racks f are applied at the
joints of the sides c, c, with the same view; or, instead of these toothed racks,
I use a curved piece of iron, as shown at g, Fig. 1. This is fixed to one of
the sides B, and has a groove or opening in it for the reception of a small
brass wheel, which is carried by a piece of iron h projecting from the other
side B, and the interior of the groove is so curved that it will produce a similar
motion of both sides B, B, in the same manner as the racks in Fig. 2. To
further secure the legs keeping the exact direction towards the centre when
nearly at their greatest degree of contraction, the inner end of each is fur-

page_text: nished with a forked iron K, which, when the leg comes near the position Z,
Fig. 1, embraces the axle M behind the wheel, and keeps the leg right; but
the fork leaves the axle as the leg becomes more extended.
Fig. 3 is an edge view of part of one of the wheels, the same letters denoting
the same parts. It shows the thickness of the parallelograms B, C, the frame
A and blocks a, the axle M, also the situation of the leg D, V, the part V
being behind the parallelogram, and united to D by bolts, and the wooden
block m, k, is the fork above described, and E, N, the two wheels which run
on the curves; they are placed behind the leg V. The foot wheel W is
attached to the end of the leg V by crooked irons which bring the centre of
the wheel into the plane of the wheels E, N, that the weight may be borne as
fairly as possible. The means by which I find the proper shapes of the curves
are thus-First; to find the curves of the iron g, Fig. 1. The machine is made
as in Fig. 1, and the parallelograms are put together, then in the place of the
iron g fix a small drawing board to the side B of the frame, and on this the
centre pin of the roller which is to run in the curve is to mark; then, by any
means which will guide the leg steadily, cause it to approach and recede
from the centre in a right line, and the centre pin will, by the motion,
trace a curve line on the drawing board, from which, as a centre line,
the groove may be formed equal in breadth to the diameter of the wheel.
To find the great curves F, K, O, R, & S, all the parts except the curves are
put together, and the whole placed horizontally, with flat, thin drawing boards
beneath it in the places where the curves are to be; upon the centre pins of the
different wheels fit wheels of lead of exactly the same diameter as the wheels
are at the bottom of their respective grooves, and fix a flat ruler to represent
the ground, which must be quite straight, from a to z, and of such a length as
will subtend a right angle from the centre M, or 45 degrees on each side of
the perpendicular, and from these points let it be rose up in the dotted lines v, v,
and y,, which are gradually curved upwards, these I call the wedges (and the
curves which are produced by them the wedge lines), and are the curves a, y, &c.,
are to describe in coming down to the ground and in rising from it; and also
that part of the curve which bears against the wheels when the ground under-
neath is higher than it was under that leg which is rising. Now turn the
wheel round by constantly applying the foot or extremity of the leg to the ruler
representing the ground and wedges, and the leaden wheels to the drawing
boards, and then will the leaden wheels describe on the drawing board the
proper curves for their respective wheels; but care must be taken that the
same side of the wheel applies to the drawing boards in drawing the curvés
that is meant to be applied when the wheel is at work.

page_text: Fig. 9 and 10 in Drawing No. 2 represent a mode of producing the con-
traction and extension of the legs, which might be substituted for the paral-
lelograms B, C, Fig. 1, the curves, rollers, &c., remaining the same. Fig. 9
is an edge view, and Fig. 10 a front view, but containing only two of the
legs D. A is a central frame revolving on the axle M; its sides a, a, a, a,
form joints or hinges for the attachment of frames B, which are again .con-
nected by joints to a second set of frames C, and these at the opposite ends
carry the legs D, with feet rollers like Fig. 1. The contraction of the legs is
permitted by the folding up of the frames on their respective joints, as shewn
at Z, or by opening the frames, as at the opposite side, they will be extended.
In all cases they will preserve their direction to the centre if the joints arc
well fitted, and the frames secured from flexure, which may be done by diagonal
braces if thought proper. The method described gives the legs no tendency to
preserve their plane of motion, and the whole dependence for this must bo on
the curves and their wheels. Lateral strength may be thus given to the frames
if required. The central frame A has projecting pieces at each of the points
marked f, forming joints for as many pair of frames L, N, which are exactly
similar to B, C, but their joints are in a direction perpendicular to them. The
outside frame N is jointed into a piece 9 projecting from the leg D, which by
this second set of frames is always firmly retained in the same plane. Fig. 4
and 5 is a second carriage having the same properties, and which I consider an
mprovement in this; the radii or legs do not alter their length, as in the
former, but slide across the centre or axle, therefore the contraction of onc
foot produces a corresponding extension of the foot on the opposite side of tho
centre. D, E, F, G, Fig. 4, are the four feet situated at the opposito ends of
the two bars D, E, & F, G, which are attached to a central wheel A, A, fitted
upon the axle M, and bearing eight grooved rollers marked a, which guide the
bars in moving endways. Each bar has an opening in the middle to admit the
axle without touching it; the bar F, G, lays before the other. The bars have
wheels, shown by the dotted circles II, I, K, L, attached to them, behind
which are to apply the curves for producing the motion. Now, if it is sup-
posed that the centre of the upper of these wheels is by any means made to
inove in the proper curve for advancing and supporting the carriage, similarly
to what is described of Fig. 1, and shown by the dotted line N, a, N, the
desired effect will be produced, and, when the bar F, G, comes to an angle of
forty-five degrees from the perpendicular, if the circumference of the same
wheel is guided by a curved iron P, Q, R, at one side, and the opposite
wheel L up a similar curve at the other side, the bar will be carried off the
ground, as shewn by E, D, Fig. 5, until the foot F, Fig. 4, reaches the ground

page_text: and the centre of the wheel L enters the dotted line curve N. The same
description applies to the motion of the other bar. The centres of the
wheels K, L, may be made to move in the curve N by forming a curved iron
of a proper shape to guide them, and applied to the circumference; but the
means which I prefer (as possessing less friction) is shewn in the Drawing.
T is a centre pin, supported over the main axle M by the frame of the car-
riage, and by a standard b. On this, as a centre of motion, the bar V (which I
call curve bar) is to revolve, and has the means of attaching either of the
wheels II, I, K, L, to the end of it, as shewn by the Figure, and which will
be hereafter described. It will be found by inspection that this dotted curve
approaches to the circle which would be described by the motion of the end of
the curve bar V, but the difference between them is completely rectified by the
following means:-The curve bar V is made as shewn in Fig. 6 & 7, with a
groove through it for a great part of its length. d & e are two sliders (distin-
guished by different colours) fitted behind the bar, with projections & coming
through the grooves to guide the sliders in a right line to and from the centre
in front of the curved bar; each of the sliders carry a lock f, g, for the recep-
tion of the wheels I, K, as shown at Fig. 4 & 5; each slider also carries a
wheel h, i, and being formed as shown in Fig. 7; the wheel of each slider is
fixed on the opposite sides of the centre T to the lock which the same slider
carries; thus, when the wheel i of the slider d is by any means thrown out
from the centre T, the lock f belonging to it is drawn towards the centre. The
necessary motion is given to the sliders and locks when in action by a curved
piece of iron dotted at , which is fixed immoveable round the centre pin T,
as shown in the other Figures, and the wheels h, i, in revolving run round
upon this, being always kept in contact with it by a larger curve or ring of
iron m, m, which surrounds k at such a distance as to form between the two a
compleat groove, in which the wheels run, and both curves are so formed that
the centres of the lock f, g, describe the intended dotted curve N, Fig. 4, when
the curve bar V turns round on its centre T. The wheels I, K, are held fast
into the locks f, g, by means of a bolt p, Fig. 6 & 7, which confines the outside
of the wheel K, holding it fast in the lock, which is formed as shown in
Fig. 8, for its reception, and is screwed or pinned fast to that part of the
slider which comes through the groove of the curve bar. The bolt of each
lock is guided by having two projecting parts p & q, which enter corresponding
holes in the back of the slider, and to lock and unlock them a curve r, s, 1, 8, is
employed. This is a ring fixed concentric with m, Fig. 4, but its upper and
lower halves are not fixed in the same plane, the lower half being bent back-
wards at the point, r, Fig. 5, as shown by the dark shaded parts. The bolts

page_text: have hooked parts g, which embrace the ring, and when the lock is upwards,,
as g, Fig. 4, the bolt is kept forwards by the ring 2, Fig. 6, and holds the
wheel K fast in it; but when the lock comes round to the part r; Fig. 5, the
bolt is withdrawn, as at f, Fig. 6, which allows the wheel to escape.
The operation of the whole machine is thus:-Suppose the carriage is sup-
ported on the foot G, Fig. 5, the wheel K of the same bar being attached to the
lock g of the curve bar, which turns round with it as the carriage advances,
and as before described; by the wheel bearing on the curve k the lock g
moves in the dotted curve till it arrives in the position, Fig. 4; the foot D is then
coming to the ground, whilst the opposite wheel I of the bar is guided by the
part O, P, of the curve into the lock f, the bolt thereof being held back by the
curve r, s, until the wheel I is completely seated in the lock, when it comes
to such a part of the curve y as to force the bolt forward, and hold the
wheel fast in the lock; soon afterwards the foot D, by the guidance of the
curve O, P, Q, R, S, and the motion of the curved bar, comes upon the
ground and takes the support of the carriage, the wheel K of the other leg F, G,
now entering the guide O, P, Q, R, S, the bolt being withdrawn to relieve the
wheel from the lock g, and it traverses down the curve O, P, Q, R, Soon after
which the wheel L goes up the similar curve S, R, Q, P, on the other side in
the manner of E, D, Fig. 5. These curves are so formed that as the whole
revolves they draw the foot E, Fig. 5, towards the centre, and extend the
other D till at the horizontal position. Both fect, D & E, are equally
extended from the centre. From this point they continue to draw in E and
extend D, until it arrives in the position of D, E, Fig. 4, the foot D being
ready to descend to the ground, and the wheel I to enter the lock f to be
carried round in the dotted curve by the motion of the curve bar and slides
as before described. The form of the parts of this machine are apparent from
the Drawing; it only remains to mention that the curves O, P, Q, R, S, are
supported by the braces p from the bed of the carriage, and the other curves
k, m, & o, are supported by the framing of it, as the Figures shew. The main
axle M is bent down between the wheel and the carriage in the manner of a
crank, which is necessary to permit the ends of the curve bar to revolve clear
of it. The ends of the bars D, E, F, & G, are bent backwards so far that
the centres of the feet wheels D, E, F, & G, are in the plane of the curves
O, P, S. To take their bearing firmly, the wheels I, K, L, & II, have each
two parallel grooves in them, one to run on the curve O, P, and the other to
be engaged in the locks of the curve bar. These two grooves are at a proper
distance asunder to admit of the latter to revolve clear behind the former.
To set out these curves I put the machine together without the curves and

page_text: place it horizontally with a ruler for the ground line, which like the first
machine is straight from a to z, Fig. 4, but it requires no wedges in place of
the small curve k. I fix a drawing board rubbed with chalk or other means
to make the wheels h & i mark on them, by engaging one of the bars, as
F, G, with the lock 9, and turning it round while the foot G of that bar is
kept in contact with the ground line from the points a to z, the wheel
will trace that portion of the curve / which is below the centre T. The upper
part of the same curve is found thus:-When the feet come to the ends a, z, of
the ground line, the curve bar V is parallel to the ground, and the bar D, E,
and F, G, will make an angle of 45 degrees with it. In this situation engage
both bars with the locks f & g, and tracing one of the legs as G along the
ground line towards the centre, it will give such a motion to the other bar E, D,
as will take the foot D off the ground in the proper wedge, and the wheel i
of that leg will trace out another position of the curve, and by a similar motion
of the other leg the curve is compleated on each side; the remainder or top
part will be finished by an arch of a circle described from the common centre
T; the curve being found may be made and finished, and then the others
may be found as follow:-m will be traced on a board properly fixed by the
outside of the wheels h & i, as they roll round the other ; and in the same
manner parts of the shapes from R to S, and also from 0 to P, will be set
out on proper boards by the wheels I & K, while they continue to be guided
by the curve bar V. But the remainder is thus obtained:-Set the bar E, D,
horizontally, and place the feet of it at equal distances from the centre,
marking with the wheels I & H the two points Q of the shapes, and from
these to P draw a gradual curve resembling the drawing, and, tracing the
wheel along the line so drawn, the opposite wheel will describe the opposite
portions of the shape, viz', from Q to R. The first portions P, Q, must be so
made that when the opposite portions Q, R, be produced from them, the
two portions on each side will agree together in making a fair curve to lead
the wheels from R to P in a regular manner into the lock. I have no absolute
rule for this, but gain it by repeated trials. The above method (concerning
the curve bar and curve ) will produce wedge lines of only one particular
shape, but if it be wished to give them any required form, it may be done by
causing the bolts to release the wheels from the curve bar at an earlier period
than above described, and so from the parts O, P, & R, S, by the above
method explained for Fig. 1, No. 1, that those parts will take the feet of the
ground, and bring them down in the wedge required to keep out the dirt from
this or my other machine. Bags of leather, linen, &c. may be made to cover
some of the joints and moving parts, which if necessary may be kept distended

page_text: by wire or other substance in the manner of powder puffs to admit of opening
and shutting with the legs, &c. If preferred, the two sliders c & d, Fig. 7,
need not cross each other, but wheels h & i may be situated on the samo side
of the centre with their respective locks. The form of the curves k & m will
then be different, but the same process will set them out. I prefer the other
method.
Fig. 11, Sheet No. 2, is a carriage having partly the same propertics of
escaping obstacles as the preceding. The Figure is an end view of a carriage
where A is the bed to which the axletrees for the wheels are usually affixed.
On these are fit a small pair of wheels, as B, to be supported upon the upper
surface of two large wheels C, N, C, N, revolving beneath the bed A, upon
axles projecting downwards from it, and inclined to each other as the Figure
shews. These wheels have legs I fixed beneath them at different points of
their edges which bear upon the road; but by the inclined position of the
wheels C, N, they only touch when at the position X, Z, being raised off the
ground when at the other positions as shewn. Therefore the legs D, as the
the carriage advances, support it at X, Z, by wheels B, B, resting upon the
upper side of C, C, and as these revolve on their axles others of the legs D
are brought successively into action, whilst the former ones are carried off the
ground and taken forwards to be employed in turn. The wheels C, N, may,
if required, be provided with cogs round their edges to turn each other, and
they must be so put together that the legs of one when at V will clear the legs
of the other. The legs are furnished with feet rollers, for as the legs revolve
with the wheels C, N, the feet do not remain in exactly the same position
on the road, whilst the carriage bears upon them, but more laterally, a small
quantity. No lateral motion is necessarily communicated to the carriage by
this means, because by the connection of the wheels C, N, it takes places in
opposite sides X, Z, at the same time, and each counteracts the other; the
feet wheels also allow the carriage to move sideways. Other wheels may be
attached to the carriage to bear upon the wheel C in the same manner as B,
but at different points where found necessary, as shown by the dotted circles L.
This method I do not consider so good for large carriages as the preceding
methods, but it may be applied as wheels to furniture, &c., in the manner of
castors in which case they will not require cogs. The lateral motion of the
legs above alluded to produces a very slight rising and falling of the carriago
as the legs successively pass; this, if thought objectionable, may be remedied
by forming the upper surface of the wheels C, N, into slight elevations and
depressions instead of being quite flat where the wheels B, B, bear upon them.
By this means the tendency of the legs in moving sideways to let the wheels

page_text: down a small quantity will not be communicated to the carriage, because
the elevated part of the wheels C, N, come beneath the wheels B, and
counteract it. The wheels must of course be allowed to rise and fall freely
upon their axles which are fixed to the beam A.
Fig. 12 & 13, No. 2, represent an axletree of my invention for the
wheels of carriages, &e. In this the bearing points are upon a cone at the
end of the box nearest to the carriage whose smallest end is nearest the
carriage, and the opposite end bears upon a conical point similar to the
spindle of a lathe. In Fig. 12, A, b, a, is the axletree, the end A being
that which is to be fixed to the bed of the carriage. b is a conical shoulder
fixed or screwed upon it, and a the point at its extremity. B is the wooden
nave of the wheel, having a metal box d, D, fitted into it. In the end d
of this a female screw is cut to receive a male screw upon a plate c, in
which is formed a conical socket exactly fitted to the cone b. In the
other end of the box D is also a female screw for the reception of a
screw E, in which is a hole for the point a to work. The collar has a
flat surface c, c, which applies against the surface d, and being screwed
tight up, will be like one piece with the box, and turn with the wheel upon
the cone, the point a keeping it properly in contact; and if wear takes
place, by screwing up E it will be made tight again. To oil the axletree
this screw must be taken out, and to take off the wheel the collar e must
be unscrewed from D, by holding it fast with proper wrench whilst the
wheel is turned round; this separates the collar from the box and the wheel
comes off. To prevent this happening by accident small screws may
be screwed through e into d, as shown dotted at r. Fig. 13 is another
method of constructing this axletree. Here the same letters refer to the
same parts, but the conc b, instead of being formed in the substance of
the axletree, is fixed upon it, and the collar c is formed out of the substance of
the box D. The conc consists of a ring 6 fitted upon a square part of the
axletree or on a cylindrical part with a fillet, and held fast by the nut t screwed
upon the axle A; the screw E at the extremity is the same as Fig. 12, except
that it is larger, because the box D, D, must be large enough withinside to
get the cone and nut into it. The wheel in this is taken off by first removing
the screw E, and then with a wrench formed like a tube to go into the box
(and catch the nut t by points or otherwise), the nut is unscrewed and the
cone comes off in cither Fig. 12 or 13. The screw E may be secured from
turning round in the box by a linchpin, by counter nuts, by small screws, or
any other method; and it may, if preferred, have a conical point to enter a
hole in the end of the axletrce. Further, I sometimes reverse the form of the

page_text: axletree, that is, I form the box D, D, in the substance of an iron axletree to
be fixed to the carriage, and adapt the part A to fit into the nave of the wheel,.
and be held fast therein by nuts, screws, keys, or any other means; and in
this case the axle will revolve with the wheel in the box.
My new-invented wheels for the communication of motion in machines in lieu
of the ordinary cog or toothed wheels, are explained by the Drawing No. 3.
One of the wheels I call the pin wheel, becaused it is provided with pins marked
B, C, D, E, Fig. 1, 2, & 5, (which pins may be furnished with friction rollers)
and which project perpendicular from its plane and communicate motion to the
other wheel called the curve wheel (or vice versa) by entering curved grooves
G, 11, I, K, made in the surface of it, as shown in the perspective view Fig. 5.
The axis, and consequently the planes, of the two wheels are so inclined to
cach other that the ends of the pins B, C, are beneath the service of the
curve wheel, and therefore enter into the grooves. But in consequence of the
inclination of the wheels as the pins approach the point D, or come to the line
between the centre of the wheels, their ends come to the surface of the wheel
so as to leave the grooves, and as they proceed towards E they are so con-
pleatly above the wheel as to pass over without touching it. The manner of
action is this:-The pin C is engaged in the groove G, and the pin B is on the
point of entering H. By the revolution of the pin wheel its pin B & C act in
the grooves, and pressing in their curves, turn the curve wheel round upon its
centre; and as the pins in succession quit the grooves in the same manner as
the pin D is supposed to have quitted the groove K the other pins very soon
after enter the next groove but one in the same manner as B is entering into
H, and by this means, before any pin leaves it groove, the succeeding pin has
just entered, and a constant action of the pins in the grooves is kept up. The
law of this action depends upon the nature of the curves which may be varied
at pleasure, so that they will turn each other with an equal velocity and with a
perfect regular motion, or by an irregular one the curve may be made to turn
with twice or three times the velocity, or almost any ratio required, also to.
turn each other in either direction; thus, in Fig. 1 & 5, both the wheels
turn round in the same direction, as shown by the arrows, but in Fig. 2 the
grooves are differently curved, and they turn contrary ways to each other. A
manner of finding the curves for these grooves is explained in Fig. 4-first
described the circle F, 1, for the size of the curvo wheel, then draw a circle
A, B, C, D, for the pin wheel, and divide it into the number of pins it is
intended to have, for example, twelve; subdivide the spaces between each of the
pins D, C, & C, B, into any number, eight for example, and figure the divisions
as shewn. Next, on the centre E draw a circle through each of the said divisions,

page_text: also a circle A, R, T, passing through the centre of the pin wheel. Now
divide the circumference of this circle into as many parts as the wheel is to
have curves; this will depend upon the ratio the velocities of the wheels are to
bear to each other; thus, if it is to turn twice for once of the pin wheel there
must be half as many curves as there are pins; therefore in the Drawing the
circle A, R, & T, is to be divided into six, and each sixth is subdivided into as
many equal parts as the spaces C & D were, viz, eight. These spaces are to
be numbered as shown. With this preparation, proceed to set out the curves
by taking the radius A, D, in the compasses and setting one point in the
division marked 3. Between T & A make a mark at g upon the external
circle, also numbered 3 (towards that side where the curve wheel is to be
elevated); (by side is not meant side of the wheel but side of the position of the
wheel, or of absolute space, as the wheel changes in turning, and what is high
in one instance is low in the next) because it passes through the division 3
between B & C. This mark will be the first point of one of the curves. Then
from the division 4 mark the circle 4 for the second point; next from the point 5
to the circle 5, and so on through the whole number of circles. This will find
a number of points forming a curve g, G, C, a, which will be the centre line of
the intended groove; and to find its breadth describe small circles round each
of these points rather larger than the pins as drawn in red.
grooves may then be drawn as tangents to these circles. The succeeding
curves II & I are found in exactly the same manner from the succeeding
divisions on the great circle, beginning on the division 3, between A, R, and so
on all round. On the opposite side of the circle are shown curves g, h, i,
proper for giving the curve wheel an equal velocity with the pin wheel, and
there will therefore be twelve of these curves in the whole. The preparation
is exactly the same, but the great circle, instead of, six, is divided into twelve,
as at the points a, r, & t, and each of these are subdivided into cight (or the
same number as between D & C), then the curves are set out from these points
exactly as before; in both these cases the wheels are considered as revolving in
the same direction as shown by the arrows Fig. 1 & 5. If it is required that
they should turn each other in opposite directions, the curves must be reversed
as shown in Fig. 2. To set out the curves the same lines and divisions as in
Fig. 4 are used. but the division between T, A, S, A, R, must be figured the
contrary way, namely, beginning at R and proceeding to A, then setting one
foot of the compasses at 5 between A & R, and the other leg in the first circle
(marked 3) towards that side where it is meant to be elevated, and as one leg
is moved towards T move the other leg towards the centre; and for the next
curve begin with the next same number towards T, and so on, and mark as
The edges of the

page_text: before. A reverse curve will here be produced, as shown dotted at 1, C, m, and
a wheel constructed with these curves, as in Fig. 2, will turn in a contrary
direction to the pin wheel, as shown by the arrows. Fig. 3 represents a curve
wheel with six curves, which therefore revolve twice for once of the pin wheel,
but the curves are so arranged that for two thirds of its revolution the curvo
wheel revolves at the rate of four to one of the pin wheel, viz, while the pins
are acting in the curves G & K the four remaining curves I, L, M, II, are
close together, and the action of the pins when in them only advances the
curve wheel double the space of the pin wheel; but the motion of the
curve wheel, even while the pins are acting in these grooves, may be
made irregular or to almost any required law; thus, at the external parts
I, L, M, where the pins first enter the grooves, are curved the same
as Fig. 2, and therefore the pins, while in these positions, turn the curvo
wheel twice as fast as they move themselves; but on entering and moving
through the returned parts i, l, m, & k, of the curves, the pin communicates a
recoiling motion to the curve wheel, which continues till the pin enters the last
portions t, u, w, and at the same time a succeeding pin enters the next curve;
this again actuates the curve wheel as in the first instance. This wheel is set
out on the same principle as the others, see Fig. 6, which is prepared exactly
as before, except the dividing of the great circle, which must in all cases be
done according to the motion the curve wheel is intended to have given to
it. In the present instance, it is first divided in 3 at A, R, S, and each of these
subdivided into eight, then from No. 3, between R & A, mark on the outside
circle 3 from 1 to the circle 4, and so on till the curve G is brought as far
as the next circle marked 3, from which place only move the leg in the large
circle half a division; then set out K by following the same process on another
part of the great circle, excepting that the leg in the large circle is continually
to be moved a whole division. To obtain the four other curves, take the
space
from Figure 3 m, to 3 q, which is one third of the whole circle, and divide
into four, viz', at m, n, o, p, q, then each of these spaces being subdivided into
four, as shewn by the red Figures 4, 5, & 6, produce the curves thus :-
Begin at m and mark on the external circle for the first division of II, then
from four (red) mark on the circle 4, and continuing this till six circles towards
the centre are marked, and the curve II is finished; this will have brought the
compasses to one division beyond n. For the returned part h mark the two
next circles towards the centre, and by returning one division for cach in the
large circle this brings the compasses back to b red; and advancing from that
point, begin the interior part w, and also that part M of the next curve, which
is compleated by a repetition of the same process on the succeeding part of the

page_text: circle, as is likewise L & I, but the interior end of the latter must be set out
from the great divisions of the circle R, S; thus, when the part i is ended
from 6 red next to q, 3, advance the compasses to the points 4, 5, 6, & 7, for
marking the successive circles till the curve is compleated. This is given only
as an example of the manner of making a wheel to turn with any required
degree of irregularity in its motion; but I claim all varieties of curves which
may be made to act on the principles here described to communicate regular or
irregular motion from the pins of a wheel. In Fig. 4 and 5 the two rings (1, 1)
and (m, m) might, if preferred, be joined together or made all in one, in
which case the bolts (p, q), not being able to get between, must be hooked the
reverse way, so that it may embrace the ring.
In witness whereof, I, the said Lewis Gompertz, have hereunto set my
hand and seal, the Ninth day of May, in the year of our Lord One
thousand eight hundred and fourteen.