Scientific American Supplement, No. 447, July 26, 1884

V >> Various >> Scientific American Supplement, No. 447, July 26, 1884

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I have assumed that in the last case the force was applied to the middle
of the beam; this corresponds to every evenly-balanced gear. In the gear
employed by Singer, which is not evenly balanced, but which derives its
good qualities from its simplicity, the same effect is produced as
if the beam were pivoted on one side of the center instead of on the
center. Thus, though both sides are driven, one is driven more than the
other. On the whole, there is no doubt that the balanced gear gives a
superior action to the clutch, for except when the two sides of the
machine meet with very different resistance, and then only when running
straight, the clutch will not compare with the other. The clutch also
gives rise to what is considered by most riders a grave defect, the
inability to back treadle, while the free pedal, which is an immediate
consequence, is considered by others a luxury.

On the other hand, this same free pedal can be obtained on
differentially driven machines to which speed and power gear have been
applied.

Of the relative merits of different forms of differential gear there is
little to be said. Perhaps it will not be thought I am unduly thrusting
myself forward, if I refer to a scheme of my own, in which no toothed
wheels are employed, but in which two conical surfaces are driven by a
series of balls lying in the groove between them, and jambed against
them by a recessed ring.

I have here a large wooden diagrammatic model, and a small working
model in steel, which shows that the new principle employed is correct,
namely, that a ball while jambed is free to turn, or if turning is able
to jamb. All Humbers, and most front steerers, employ differential
gearing; in some front steerers the clutch of necessity is used.

Neglecting for the present the different modes of transmitting power
from the pedals to the main wheels, it is possible now to consider the
four typical builds of tricycle. The only advantage that a rider can
find in a rear-steerer is the open front, so that in case of accident
he can more easily clear himself of his machine; as I have already
remarked, this power of instantly escaping seems to be considered by
many as of no importance.

In a rear-steerer which has not an open front, whether driven by a
clutch or by differential gear, I fail to discover any good quality.
The steering of a rear-steerer is so very uncertain, that such machines
cannot safely be driven at anything like a high speed, because any wheel
meeting with an obstruction will, by checking the machine, diminish the
weight on the steering wheel just at the time when a greater weight than
usual should be applied. It is for the corresponding reason that the
steering of a front-steerer is so excellent; the more the machine is
checked by obstruction, by back treading, or by the brake, the greater
is the weight on the front wheel.

For shooting hills, or for pulling up suddenly, no machine of any kind
will compare with a good front-steerer. In all respects it is superior
to the rear-steerer if we except the open front, but against this may
be set the fact that on many the rider can mount from behind, or can
dismount in the same manner while the machine is in motion. Experience
shows that the front-steerer is for general excellence, safety, easy
management, and light-running, the best all-round tricycle that is to be
had.

The Humber build, which departs less from the ordinary bicycle than any
othar, is far superior to all others for speed; it is, however, somewhat
difficult to manage, for the steering is not only delicate, but
critical, requiring constant care lest a stone or other obstruction
should take the rider unawares, and steer the machine for him.

The control which a skillful rider of the Humber has over his machine is
wonderful; the elegance of the machine among tricycles is unequaled.
So great a favorite is this form, especially among the better class of
riders, that almost every firm have brought out their own Humber, each
with a distinguishing name.

The only improvement or change, whichever it may be, that has been made
by others with which I am acquainted, is the triple steering, in which
the hind wheel moves the opposite way to the others. The corresponding
change in the bicycle was soon discarded; I do not know what advantage
can result from the increased delicacy of steering here. I should have
thought it delicate enough already.

One noticeable change in the front-steering tricycle, which has been
largely made, lately, is the substitution of central for side gearing,
in consequence of which bicycle cranks can be employed, instead of
the cranked axle, with its fixed throw. This gives an appearance of
lightness which the older types of machine do not possess.

I now come to that very difficult and all-important subject, the method
of transmitting power from the body of the rider to the main axle. Next
to the structural arrangement, this is most important in distinguishing
one type of machine from another.

The first to which I shall refer is the direct action employed on the
National and the Monarch tricycles. It is obvious that by having no
separate crank shaft, much greater simplicity and cheapness and less
friction are attained than can be possible when the extra bearings and
gear generally used are employed. In this respect the direct action
machines undoubtedly have an advantage, but an advantage of any kind may
be too dearly bought, as it certainly is here.

In the first place, the direct action can only be applied to a
rear-steering, clutch-driven machine, or single driver, for if the
wheels were not free to run ahead, it would be impossible to go round a
curve. In the second place, the rider must be placed at such a height
for his feet to work on the axle that the machine, of necessity, is very
unstable, and is likely to upset if ridden without great caution round
a curve. Thirdly, to diminish as far as possible this last objection,
miserable little wheels must be employed, which cannot be geared up,
that is, made to travel faster than the treadles, and so be equivalent
to larger wheels. Therefore, though it is likely that at such low speeds
only as it is safe to run such a machine it may move more easily than a
machine of a recognized type, and though direct action would undoubtedly
be advantageous if it did not entail defects of a most serious order of
magnitude, we may dismiss this at once from our consideration. It is
true that in the Monarch a few inches of height are gained by the
hanging pedals, but I question very much whether one machine is much
better than the other.

The chain which is used on almost every make of machine cannot be
considered perfect; it is, on the whole, a dirty and noisy contrivance,
giving rise to friction where the links take and leave the teeth of
the pulleys; stretching, or rather lengthening, by wear, and, finally,
allowing back lash, which is most unpleasant. In spite of all this, it
affords a convenient and reliable means of transmitting power, which is
applicable to every type of tricycle, except one.

Instead of a chain, an intermediate or idle wheel has been tried, but
this has not been found advantageous. The intermediate wheel has been
removed, and the crank and wheel pulley allowed to gear directly
together, making reverse motion of the feet necessary, and possibly
reducing friction.

The crank and connecting rod are employed in some machines. If there are
two only, they must not be placed in opposite positions, but be fixed at
an angle, so that there are times when each rod is under compression,
a strain which delicate rods cannot stand. In the three-throw crank,
employed in the Matchless tricycle, this objection is obviated, for one,
at least, is at all times in such a position as to be in tension. The
objection to the crank is the fact that it weakens the shaft, and that
it can only be used with a clutch, not with a differential gear.

The most silent, neatest, and cleanest driver, the one of which the
working friction is least, is the endless steel band, so well known in
connection with the Otto bicycle. This is not, as far as I am aware,
employed on any tricycle, makers probably fearing lest it should slip.
The Otto shows that it can safely be employed.

I have devised a scheme, of which I now show a model, which seems to me
to be free from the objections which may be urged against other methods;
but I, of course, cannot be considered in this respect a judge.
Eccentrics are well known as equivalent to cranks, but if used in the
same way, with a connecting rod, either fatal friction or enormous
ball-bearings would be necessary. Instead of these, I connect two pair
of equal eccentrics by an endless band embracing each, so that the band
acts like a connecting rod without friction, and, at the same time,
acts by its turning power as on the Otto, thus making two eccentrics
sufficient instead of three, and carrying them over the dead points.

There is one more system of transmitting power employed on a few
machines. In these, a band or line passes over the circumference of a
sector or wheel, and the power is directly applied to it. The motion of
the feet in the omnicycle, and of the hands and body in the Oarsman, is
therefore uniform. There would be no harm in this if it were not for the
starting and the stopping, which cannot be gradual and at the same time
effective in machines of this type. For this reason, a high speed cannot
be obtained; nevertheless, these machines are better able to climb hills
than are tricycles with the usual rotary motion, for, at all parts of
the stroke--which may be of any length that the rider chooses--his
driving power on the wheels is equal. The ingenious expanding drums on
the omnicycle make this machine exceptionally good in this respect, for
increased leverage is effected without increased friction, which is the
result of "putting on the power" in some of the two-speed contrivances.

Having spoken of the Oarsman tricycle, I must express regret that I have
not been able to find an opportunity to ride on or with the machine, so
that I cannot from observation form an opinion of its going qualities.
There can be no doubt that the enormous amount of work that can be got
from the body in each stroke on a sliding seat in a boat must, applied
in the same manner on the Oarsman tricycle, make it shoot away in a
surprising manner; whether such motion, when continued for hours, is
more tiring than the ordinary leg motion only, I cannot say for certain,
but I should imagine that it would be. The method by which the steering
is effected by the feet, and can with one foot be locked to a rigidly
straight course, is especially to be admired.

There is much difference of opinion with respect to the most suitable
size for the wheels of machines. Except with certain machines, this has
nothing to do with the speed at which the machine will travel at a given
rate of pedaling, for the wheels may be geared up or down to any extent,
that is made to turn more quickly or slowly than the cranks. Thus the
most suitable speeding is a separate question, and must be treated by
itself.

Large wheels are far superior to small wheels in allowing comfortable,
easy motion, a matter of considerable importance in a long journey. They
are also far better than small for running over loose or muddy ground,
for with a given weight upon them they sink in less, from the longer
bearing they present, and this, combined with their less curvature,
makes the everlasting ascent which the mud presents to them far less
than with a smaller wheel. On the other hand, the large wheel is
heavier, and suffers more from air resistance than the small wheel. For
racing purposes a little wheel, geared up of course, is certainly better
than a high wheel; for comfortable traveling, and in general, the high
wheel is preferable. Though this is certainly the case, it does not
follow that large wheels are worth having on a machine when there is
already one little wheel. If the rider is to be worried with the evils
of a little wheel at all, it is possible that any advantage which large
wheels would give him would be swamped by the vibration and mud-sticking
properties of the small steering wheel. One firm, in their endeavors
to minimize these evils, have designed machines without any very small
wheels; all three wheels are large, and a steadier and more comfortable
motion no doubt results.

High and low gearing are the natural sequel to high and low wheels. Of
course the lower the gearing the greater is the mechanical advantage in
favor of the rider when meeting with much resistance, whether from wind,
mud, or steepness of slope. In spite of this, for some reason which I
cannot divine, the machines with excessively low gear do not seem to
obtain so great an advantage in climbing hills as might be expected. To
make such a machine travel at a moderate speed only, excessively rapid
pedaling is necessary, and the rider is made tired more by the motion of
his legs than by any work he is doing. The slow, steady stroke by which
a rider propels a high-geared machine is far more graceful and less
wearying than the furious motion which is necessary on a low-geared
machine. The height up to which the driving-wheels are usually geared
may be taken as an indication of the ease with which any class of
machines runs. A rider on a low-geared machine can start his machine
much more quickly than an equal man on one that has high gearing, and
therefore in a race he has an advantage at first, which he speedily
loses as his rapid pedaling begins to tell. For ordinary riding the
slight loss of time at starting is a matter of no importance whatever.

There are several devices which enable us to obtain the advantages of
high and low gearing on the same machine, which at the same time give
the rider the benefit of a free pedal whenever he wishes. On some single
driving rear-steering tricycles the connection on one side is for speed,
and that on the other for power, either being in action at the wish of
the rider, or both speed and power combinations are applied on the same
side. To drive with a power gear a single wheel only seems to me to be
the height of folly; in my opinion no arrangement of this type is worthy
of serious attention. Among the better class of machines there are three
methods by which this change is effected--first, that employed on the
omnicycle, to which I have already referred; secondly, an epicyclic
combination of wheelwork which moves as one piece when set for speed,
thus adding nothing to the working friction except by its weight, but
which works internally when set for power, thus reducing to a small
extent, by the additional friction, the gain of power which the rider
desires; thirdly, a double set of chains and pulleys, each set always in
movement, so that, whether set for speed or power, there is rather more
friction than there would be if there were no additional chains, but
these are free from that increased friction due to toothed wheel
gearing, from which the epicyclic contrivances suffer only when set
for power. There is much difference of opinion whether any of these
arrangements are worth carrying, for perhaps nine miles, for the sake of
any advantage that may be obtained in the tenth. It is on this account
that the drums on the omnicycle are so excellent; whether expanded or
not, there is, on their account, no loss of work whatever, for there is
no additional friction. The subject of these two speed gears will, I
hope, be discussed; it is one which, though not new, is coming more to
the front, and about which much may be said.

Having now dealt with the means by which tricycles are made to climb
hills more easily, I wish to leave the subject of bicycles and tricycles
altogether for a few minutes, to say a few words which may specially
interest those who are fond of trying their power in riding up our best
known hills. The difficulty of getting up depends to a large extent on
the surface and on the wind, but chiefly on the steepness. The vague
manner in which one hill is compared with another, and the wild ideas
that many hold who have not made any measurements, induces me to
describe a method which I have found specially applicable for the
measurement of steepness of any hill on which a cyclist may find
himself, and also a scheme for the complete representation of the
steepness and elevation of every part of a hill on a map so as to be
taken in at a glance. The force required to move the thing up a slope is
directly proportional not to the angle, but to the trigonometrical sine
of that angle. To measure this, place the tricycle, or Otto--a
bicycle will not stand square to the road, and therefore cannot be
used--pointing in direction at right angles to the slope of the hill, so
that it will not tend to move. Clip on the top of the wheel a level, and
mark that part of the road which is in the line of sight. Take a string
made up of pieces alternately black and white, each exactly as long as
the wheel is high, and stretch it between the mark and the top of the
wheel. If there are n pieces of string included, the slope is 1 in n,
for by similar triangles the diameter of the wheel is to the length of
the string as the vertical rise is to the distance on the road. This
gives the average steepness of a piece sufficiently long to be worth
testing, because an incline only a few feet in length, of almost any
steepness, can be mounted by the aid of momentum.

There is only one process, with which I am acquainted, which supplies a
method of representing on a map the steepness of a road at every part.
Contours, of course, show how far one has to go to rise 50 or 100 feet,
but as to whether the ascent is made uniformly or in an irregular
manner, with steep and level places, they tell us nothing. Let the
course of a road be indicated by a single line where it is level, and by
a pair of lines where inclined. Let the distance between the lines be
everywhere proportional to the steepness, then the greatest width will
show the steepest part, and an intermediate width will show places
of intermediate steepness; the crossing of the lines, which must be
distinguishable from one another, will show where the direction of the
slope changes. Further, the size of the figure bounded by the two lines
will show the total rise; a great height being reached only by great
steepness or by great length, a large figure being formed only by great
width or by great length. Those who are mathematically inclined will
recognize here that I have differentiated the curve representing the
slope of the bill, and laid the differential curve down in plan.

Having wandered off my subject, I must return to more mechanical things,
and give the results of some experiments which I have made on the balls
of ball bearings. There is no necessity to argue the case of ball vs.
plain bearings, the balls have so clearly won their case, that it would
be waste of time to show why. Of the wear of the twelve balls forming
one set belonging to the bearings of the wheels of my Otto, I have on a
previous occasion spoken; I may, however, repeat that in running 1,000
miles, the twelve balls lost in weight only 1/20.8 grain, or each ball
lost only 1/250 grain. The wear of the surface amounted to only 1/158000
inch; at the same rate of wear, the loss in traveling from here to the
moon would amount to only 1/34.3 of their weight. I examined each ball
every 200 miles, and was surprised to find that on the whole the wear of
each, during each journey, varied very little. The balls experimented on
were a new set obtained from Mr. Bown. I also had from him one ball of
each of each of the following sizes 3, 4, 5, 6, and 7 16ths of an inch
in diameter, as I was curious to know what weight they would suppport
without crushing. As as preliminary experiment, I placed a spare 5/16
ball between the crushing faces of the new testing machine at South
Kensington, and applied a gradually increasing force up to 7 tons 91/2
cwt., at which it showed no signs of distress. On removing it I found
that it had buried itself over an angle of about 60 deg. in the hard steel
faces, faces so hard that a file would not touch them. Those marks will
be a permanent record of the stuff of which the ball was made. The ball
itself is sealed in a tube, so that any one who is curious to see it can
do so. Finding that the crushing faces were not sufficiently hard, I
made two anvils of the best tool steel, and very carefully hardened
them. These, though they were impressed slightly, were sufficiently good
for the purpose. In the following table are the results of the crushing
experiments:

3/16 ball at 2 tons 13 cwt. did not break, but crushed on removing part
of the weight.

1/4 ball at 3 tons 15 cwt. did not break, but crushed on removing part of
the weight.

5/16 ball at 4 tons 9 cwt. broke.

3/8 ball at 8 tons 6 cwt. did not break, crushed under another 120 lb.

7/16 ball crushed before 3 tons, with which I was starting, had been
applied. Examination showed that the steel bar of which it was made had
been laminated.

These experiments do not tell much of importance; they are curious,
and perhaps of sufficient interest to bring before your notice. The
fragments are all preserved in tubes, and labeled, so that any one who
likes to see them can do so.

Of the advantage which a machine which will collapse or fold up when
desired, but retain its form on the road, offers in convenience, it is
unnecessary for me to speak.

Of double machines, the Rucker tandem bicycle seems to me to be in every
respect the best, but I should add that I speak only from imagination
and not from experience. The independent steering, the impossibility of
capsizing forward or sideways, the position of the rider over his work,
the absence of any little wheel with its mud throwing and vibrating
tendencies, combine to make a machine which ought to be superior in
almost every desirable quality to any other; what it may be in practice
I hope to hear in the discussion.

Of double tricycles, the Sociable has been tried by many, and is
practically a failure in so far as traveling quickly and easily
is concerned. The Tandem, though it presents so objectionable an
appearance, seems likely to become a favorite, for it surpasses any
single tricycle, and rivals the bicycle in speed. How it may compare in
comfort or in safety with the single machine, perhaps those few who are
well acquainted with them will say; at any rate, in the case of the
Humber, greater stability is given to the steering, owing to the weight
of the front rider.

Time will not allow me to say more of these machines, or to attack the
subject of steam, electric, or magic tricycles, which I had hoped to do.
With steam and electricity we are well acquainted; by magic tricycles, I
mean those driven by a motor which, without any expense, will drive one
twenty miles an hour, up or down hill, with perfect safety. Highway
regulations, and certain reasons not well understood, have at present
prevented these contrivances from making a revolution.

There remains one machine which must be considered separately, for it
cannot be classed with any other. This is the Otto bicycle. My opinion
of this machine is so pronounced that I do not care to state it fully. I
shall merely give the reasons why I prefer it to anything else, and in
so doing I shall be taking the first step in the discussion, in which it
will be interesting to hear from riders of other machines the reasons
for their preference.

In the first place, the evils of a third or little wheel, the cause of
trouble in all tricycles, are avoided. There is none of the vibration
which makes all other machines almost unbearable to Ottoists, vibration
which tricyclists have learnt to consider a necessary accompaniment of
cycling, but which has, no doubt, been diminished by the use of the
spring support of the front steering Humber. It would be presumptuous
in me to make any remarks on the effect of this vibration on the human
system; we shall all be anxious to hear what our Chairman has to say on
this point. By having only two wheels, we have only two tracks, so that
we can travel at a fair speed along those places in the country called
roads, which consist of alternate lines of ruts and stones, where a
three-track machine could not be driven, and where, from the quantity
of loose limestone in the ruts, a little wheel of a two-track tricycle
would be likely to suffer. By having no little wheel, we can ride in
dirty weather without having the rest of our machine pelted with mud, so
that cleaning takes less time than it does with anything else. As I have
already remarked, the small wheel is the culprit which makes the bicycle
and tricycle drive so heavily on a soft road. The ease with which the
Otto can therefore be run through the mud astonishes every one. Having
no little wheel, we can obtain the full advantage of the high 56
inch wheel, which almost every one prefers. As I have ridden all
combinations, from a 50 inch geared up to 60 inch, to a 60 inch geared
level, I can speak from experience of the increased comfort to be
derived from these large wheels, though for speed only they do not
compare with the smaller and lighter wheels geared up. A further point
gained by the use of two wheels only is the fact that the whole weight
of machine and rider is on the driving-wheel, as it is also on the
steering-wheel, so that by no possibility can the wheels be made to slip
in the driving, or to fail in steering from want of pressure upon them.

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