118 



THE €IVIL E^fGINEER AND ARCHITECTS JOURNAL. 



[April, 



This sprinsr is ui^ed to sustain loads not exceeding C tons on the 

 four spriiif^s exclusive of the wapon body ; the wagon body weighs 

 barely 2 tons, making the total load about 8 tons, or 2 tons per 

 spring. 



By actual experiments this spring deflects with 



1 ton 2 tons 3 tons 



J-inch 2 inches Scinches 



and will prove flat witliont setting or breaking. It is to be noted 

 that in originally proving this spring flat it had set about f-inch, 

 but that with the same extent of ])roof it will not again perma- 

 nently set, having this property in common with other materials. 

 This spring would well sustain a load of 3 tons in actual work, as 

 the concussions received upon the rails would probably not at any 

 time increase the deflection ^-inch. consequently the load of 2 tons 

 is being sustained on a spring far too rigid, to the detriment of t!ie 

 road and the wagon, and the original first cost is considerably 

 more than it need have been. Formerly, various plans were 

 ado])ted to lessen the friction at the ends of the springs by the use 

 of rollers, but these plans are now obsolete, the amount of friction 

 not being found practically detrimental. The points of the plates 

 of laminated springs were formerly tapered in tliickness, but now 

 the usual plan is to form the taper in the breadth by cutting the 

 plates at the ends in a triangular form. This method is found 

 much more certain in its effect, is neater in appeai-ance, and 

 cheaper in manufacture. The cutting is generally performed 

 either with the shearing machine or hetween dies in a punching 

 machine, the scraps being used in the melting-pot for cast-steel. 



Fig. 3 represents the Wagon Bi'/trinij Spriny, or more correctly 

 speaicing, pi-np. in extensive use on the North Branch of the London 

 and Nortli-U'estern, the South St.-iffordshire, Caledonian, and othf r 

 Railways, which may well be designated by the term cheiip. 



This spring is 2 ft. H in. Ions, 4 in. wide, 2 in. thick, camber t in. 

 consisting of 4 plates 4-in. thick, and weighs about 40 lb. Actual 

 experiment furnishes the following deflections — 



1 ton 2 tons 3 tons 



f-inch J-inch Ig inch 



The cause of the immense sustaining power of this spring has been 

 exi>lained before in the observations on thick and thin plates. 



The writer has already endeavoured to explain that the ordinary 

 spring (fig. 1 ) is too rigid; what therefore must be the wear and 

 tear of rails, wheel tyres, vibration to the axles, and general wear 

 and tear to the wagon and load causeil by this rigid spring.'' Com- 

 ]iared with fig. 1, tills spring affords less relief in the proportion of 

 (i to Ifi, and is the furthest removed from the object required to 

 he attained. 



The Wagon Bearing Spring in extensive use on the Midland. 

 Great AFestern, and other Irish Railways, and on the London and 

 North AVestern Railwaj', is the ordinary spring as in fig. 1, but 

 with eyes rolled at the ends and hung on scroll-irons. The advan- 

 tages of this form of spring are the great space passed through and 

 quickness of adaptation to the inequalities of the road, in conse- 

 quence of the deflection of the end shackles caused by the deflection 

 of the spring, and consequent elongation between the centres of 

 eyes of shackles; also the rubbing friction at ends is almost entirely 

 obviated. The disadvantages are, first, that to carry a given loail 

 a much greater quantity of material is required, as from the 

 circumstance of a great portion of the space between the solo-bar 

 and the axle-box being taken up by tlie sci-oll-irons and shackles, 

 the radius of the curve of the spring is much reduced, and a 

 thicker spring consequently required. Secondly, the tension on 

 the sole-bars tending to hog the wagon frame, being the re\erse of 

 the action of the ordinary spring. Thirdly, in consequence of the 

 great space jjassed through by the deflection of this spring, the 

 variations of the load will considerably vary tlie height of the 

 bufiers from the rails. 



Fig. 4 represents the now nni\ersal Carriage Bearing Spring 

 originally introduced by Mr. Wharton on the London and North- 

 \\'estern Railway, as the result of repeated pi-actical trials and im- 

 ])rovements: theory would probably have never attained a similar 

 result. Tliis spring is .5 ft. 3 in. long, 3 in. wide, 2f J in. tliick 

 and consists of !) ]ilates J,- in. thick; the ends of the plates are 

 what is technically termed long spear-pointed. Fig. 4 represents 

 the spring when loaded, and the peculiar camber before fixing is 

 made by setting the jilates entirely at the centre, instead of the 

 plates being set into a curve throughout their whole length as in 

 other springs. In fixing this spring the tension-brace is adjusted 

 between scroll-irons, with intervening c,om]iensating shackles. 

 The tension-lraee is 3 in. by -J-in. and thickened at the ends to 



g-in. The spring is then compressed between the axle-box and the 

 brace. The action of the spring and brace is that of a lever spring 

 combined with a tension-brace, but the spring is so thoroughly 

 over|>owered by the leverage of the brace and the weight of the 

 load, as to have little or no power of reaction or displacing the 

 inertia of the load, beyond that of recovering its original position; 

 thus affording the well-known smoothness and steadiness of action 

 of this construction of carriage S))ring. The brace is acted upon 

 principally at the point A, but ne\ ertheless when the blow from 

 the road strikes the point B, and the si)ring and brace straighten 

 at that point, the curving and straightening of the brace at A is 

 compensated l)y the straigtening and lengthening at C, the amount 

 of tension at D being thus at all times about the same. The ten- 

 sion brace steadies and counteracts the power of the spring, and 

 the spring partly relieves the brace by sustaining it at A. 



This combination also aft'ords the means of firmly attaching the 

 axle-box to the spring and brace, and thus holding it independent 

 of the axle-guards, which in this case are wholly ^i(«)-rf.?, not guide.s\ 

 the guards neither touching the axle-bo.x on the edge or side. 

 Thus the efl^ects of the inequalities of the road, laterally and hori- 

 zontally, are only transmitted to the body through the elastic 

 medium of the spring. 



Springs of the same construction, but shorter and lighter, are 

 now generallyjused for horse-boxes, carriage-trucks, and break-vans 



Buchanan's Bearing Spring consists of four fiat horizontal plates 

 4 ft. long, 4 in. wide, and tapered in thickness from ;^-in. at the 

 centre to |-in. at the ends, and fastened in the centre and 

 impinging at the ends only. See fig. 5. 



it does not seem to posess any advantage over the ordinary 

 laminated spring, excepting that the friction between the plates is 

 entirely avoided except at the ends; but at the same time it must 

 be borne in mind that in ordinary laminated springs the steel is 

 rolled concave, therefore the plates bear at the edges only, which 

 very considerably reduces the friction. 



The disadvantages of this spring appear to be, firstly, that the 

 extreme points of support are when tlie spring is weighted con- 

 siderably below the centre bearing, necessitating the use of deep 

 scroll-irons in carriages and bearing-blocks in wagons. 



Secondly, the manufacture is costly and uncertain, from the fact 

 of the plates being tapered in thickness, and the difl[iculty of 

 hardening and tempering plates that taper in thickness. 



Thirdly, when fixed with scroll-irons the sustaining power is 

 partly derived from its effect as a tension brace. 



Adams's Bow-Spring, of the size used for passenger vehicles, is 

 6 ft. long from centre to centre of spring eyes, and the versed sine 

 about 14 in. when weiglited; the plates are 8 in. broad in centre 

 and tapered in widtli to 5 in. at the eyes, and the thickness is 

 /j-inch. 



The advantages of this spring are, firstly, it holds the axle-boxes 

 without the intervention of the guards in the same manner as pre- 

 viously described with refei'ence to the carriage bearing spring-. 

 Secondly, that the top links permit the wheels, axles, and axle- 

 boxes to traverse laterally in passing curves and other impediments. 

 Thirdly, that the quick adaptation of tliis spring to lateral ami 

 perpendicular blows preserves the inertia of the body almost wholly 

 from displacement at moderate speeds. 



The disadvantages are, that at high speeds and on a bad road 

 the reaction of this spring is so great as to cause a rebound, and 

 the gradually increasing momentum from each successive blow 

 occasions very considerable oscillation. 



This jiroperty has completely negatived its use for 4-wheeled 

 carriages; but it is now used successfully under the 8-wheeled 

 carriages on the North AVoolwich branch, and there works to con- 

 siderable advantage, permitting the wheels to adapt themselves 

 freely to the curves of tlie road. The oscillation is there almost 

 obviated, from the fact tliat tlie blows are received upon eiirht 

 points, and that the reactive power of a blow on one of the eight 

 points is not sufficient to disturb the inertia of the load. This 

 spring has been and is now used to a very considerable extent on 

 (j-wheeled carriages in Germany; but it is to be observed that tlie 

 speed on the Continent is generally slower than in England. 



A Spiral Hearing Spring is represented in fig. 8, I'late IV. The 

 dimensions of these springs as used under the tenders of the Mid- 

 land Railway were 9 in. height and ti in. diameter, and they ivere 

 made of g-in. round steel. Within this coil was fixed a second 

 spiral of smaller diameter, coiled the reverse way to prevent the 

 coils interfering. The action of a spiral spring is principally 

 torsion of the steel bar through the angle A C B, and partly lateral 

 deflection from the increase of diameter when the spring is com- 



