CHAPTER X.
ANTI-VIBRATORS AND SPRING FORKS.
The abstract terms of the heading have, so far, generally been applied to certain devices constituting an elastic connection between the standards of the wheels (1), or, more precisely, between the front fork and backbone. The more recent forms of anti-vibrators are (2) the spring hinge about midway in the rear frame, or backbone, of the machine; (3) the spring joints at the extremity of the front fork connecting with the forward wheel axle; (4) the spring fork proper, in which the extensions are either wholly or in part elastic. The last two are, to my mind, the most deserving of praise. In the first named above, the shock is mainly confined to the front half of the machine,—that is, to the front wheel, its fork, and handle-bar,—while in the last two the front wheel alone receives the concussion to the full extent, an intervening spring preventing the transmission of the shock to other parts of the system. When it comes to be fully appreciated by the fraternity that the shock sustained by the machine and rider is not only to be treated as a matter of comfort or discomfort, but that it has other very important claims to our consideration, we may expect it to be more fully discussed. Not that we care so much about the vibration loosening every joint, screw, and pin in the entire contrivance, which makes it worn out, so called, when it has scarcely begun to wear,—of course, in the general march of progress, we expect to remedy that also,—but it is the momentum we are most after. The writer has always been one who has had a constitutional aversion to workingup a speed and then having it all knocked out by a stray stone.
The difficulty experienced by inventors in the line of anti-vibrators appears to be, that while acquiring the desired elasticity in the proper direction an elasticity in other directions has followed, making the machine feel unsteady and capricious, especially in the steering. This undoubtedly valid difficulty in the way is worthy of careful consideration before accepting an anti-vibrator; in fact, the very end desired can easily be missed in an imperfect device, as it might, while holding momentum in one direction, lose it in another. I cannot better express my opinion as to the general requirement of a good anti-vibrator than to say, get plenty of spring, but acting in the plane of momentum and gravity, and get it as quickly as possible; that is, at the connection of the wheels with the forks, or at the outer end of the spokes if it can be done withoutinterfering with the rigid transmission of power to the driving-rim.
Recent American anti-vibrator.
Recent American anti-vibrator.
It is always difficult to apply any attachment to the driving-wheel of a machine; in the Ordinary it would be beneficial to attach an anti-vibrator to the forward wheel, but as a matter of construction it would be about as difficult to do this as it would be to attach it to the rear wheel of the Safety.
We hope to see and may expect a number of devices to be offered by makers which will fulfil all requirements. Appended find a cut of one recently patented, of which I can speak with some confidence from having used a similar contrivance in experiments in this connection.
The figure here, as in the patent, shows the connecting-rod swinging through an almost useless arc of action, but the general plan is good; not, however, as neat as some others.
A great maker has of late, however, adopted a device which, to my mind, doesnotfulfil all of the requirements; it is still confined too much to a vertical action, and has really no horizontal amplitude unless the machine is ridden by a very heavy man, in which case the spring will assume a very abnormal position.
Other makers have adopted the joint to the centre of the frame or backbone of the Safety type (No. 2 above), so constructed that the pedals are also provided with a vertical motion; this certainly helps to isolate the man from vertical concussion, and it is good; yet the horizontal give is lacking in these machines, and the front fork, together with the handle-bar, still receives a shock and loses in vibration. Later, an inventor has shown a new pedal in which, apparently, the rubber works upon a spring and has a vertical motion under the pressure of the foot. This is a deserving though a misguided effort. The connection of the man with the apparatus through which the power is transmitted to the machine should be as direct andrigid as possible: all springs should be beyond this point. An elastic pedal is quite a different device from that named in the last preceding paragraph, in which the crank-shaft has a vertical motion and the “connecting-link,” together with the source of power (the man), are all rigidly and inelastically connected together, the whole, as a system, swinging vertically by a spring.
An English firm has for several years had upon the market a machine which, from its external appearance, is all springs; the inventor thereof deserves greater credit than the success of the venture has awarded him. If in the early samples put upon the market the parts had not been so frail and the appearance so exceedingly homely, he might have fared better.
Several premature freaks of advancement in this matter of springs have occurred, but the general progress has been quite logical. First, we had the saddle provided with a very feeble amount of elasticity, then an increased amount, until makers vied with each other in producing the best spring for the old Ordinary; then we had the spring connection between the front fork and backbone in the Safety, confining the shock to the forward half of the machine; and then came the spring fork isolating the entire system except the front wheel from the shock. So far the inventions have been practical and are in use. Next we have a worthy, but I fear impractical, inventor, who proposes springs between two outer rims of the wheel or substantially at the ends of the spokes, thereby confining the concussion to one rim of the front wheel in the manner shown in cut. (See English spring rim.)
This appeared to be the ultimatum, but a shrewd American inventor has “gone him one better” and proposes to confine the shock and vertical thrust to a mere part of the rim. This invention was patented in the United States in 1889, and, if practical, would simply cause the wheel to roll over the obstruction almost as a man would step over in walking,—an idealstate of affairs, to be sure! Such a wheel would not only aid man in his transmigration over smooth roads, as claimed for the solid wheel in the fore part of this book, but would be available on the cross-ties of the poorly-ballasted railroad; and let the wheel be but tall enough, and he may yet go over that old-time impedimentto cross-country locomotion, the rail fence, as unwittingly as though it had not been there at all.
English spring rim.
English spring rim.
American patent flexible rim.
American patent flexible rim.
One of the grandest ideas in the way of anti-vibration is suggested by the following from theAmerican Athlete:
“An inventor of Belfast, Ireland, has made what he calls a ‘Pneumatic Safety,’ the tires of which are two inches in diameter, and ofhollowrubber, so that they contain air, which vastly increases their elasticity. The result is most favorably regarded by Irish wheelmen, and at the recent races at Belfast a rider on a ‘Pneumatic’ won all the four first prizes, the hollow rubber being described as phenomenally successful on the rough grass track.”
“An inventor of Belfast, Ireland, has made what he calls a ‘Pneumatic Safety,’ the tires of which are two inches in diameter, and ofhollowrubber, so that they contain air, which vastly increases their elasticity. The result is most favorably regarded by Irish wheelmen, and at the recent races at Belfast a rider on a ‘Pneumatic’ won all the four first prizes, the hollow rubber being described as phenomenally successful on the rough grass track.”
If the liability of cutting and collapsing were not so apparent in this device, I would be inclined to think it would have a great future.
By way of conclusion of the foregoing chapters on curves, momentum, and springs, permit me to again call attention to the remarkable fact that a rear-driving Safety of absolutely rigid construction, striking an obstacle four inches high, loses one-half of its entire momentum and that of the rider. Think of it! Not that we often strike a four-inch obstruction, but that it does not take very many smaller to make one. Thus we are continually wasting strength when there is really no substantial necessity or occasion for it, and the writer, for one, feels ready to maintain that even double the weight (harmful as extra weight always is) in a machine is justifiable if in so increasing the weight we can do away with this most potent source of loss of energy. The bicycle, or single-track machine, too, affords an unusual chance for proper manipulation of momentum, and the rear-driver a special opportunity for the attachment of proper springs. In a two-track machine, on the other hand, we are compelled to supply springs with lateral motion as a necessary appliance for the comfort of the rider, which lateral motion results in loss of momentum and kinetic energy, whereas in the bicycle our comfort and energy are all confined to one plane; so that all we want now is to have our springs adroitly and amply applied to operate in this plane and no other, and we shall then find that we invariably save our momentum, preserve our comfort, and retain our strength. It will be a long time before we can expect to realize our dream of perfection in easy riding, or to find cyclers hunting for the rough roads; nor do we expect to see them peering eagerly forward through the misty morning, greeting the dawning obstacle as glad tidings of “Land ho!” but we do expect very soon to see the discomfort and loss of power now encountered in a great measure overcome. If some one will only get us over the sandy places as nicely as we can reasonably expect, in the future, to glide over the rough places, then we will all be happy.