Messrs. J. & H. McLaren, of the Midland Engine Works, Hunslet, Leeds,
England, for several years past have devoted considerable attention to
the question of mounting traction engines on springs. The outcome of
this is the engine in question, the front end of which is carried by a
pair of Timmis spiral springs, resting on the center pin of the front
axle, which is on Messrs. McLaren's principle, which enables it to
accommodate itself to the inequalities of the road without throwing any
undue strain on the front carriage. The chief difficulty hitherto has
been to mount the hind end on springs without interfering with the spur
gearing, which must be kept perfectly rigid to prevent breakage of the
cogs. This is entirely provided for by the new arrangement, whereby all
the spring is allowed for in the spokes of the wheel itself, which will
be clearly seen on reference to the illustrations, in which Fig. 1 is a
perspective view of the engine, while Fig. 2 shows a detail view of the
wheel. The rim of the wheel is built up in the ordinary way of strong
T-iron rings, with steel crossplates riveted on. The nave of the wheel
has wrought-iron ribs to which the spokes are bolted. These spokes are
made of the best spring steel, specially manufactured and rolled for the
purpose, 9 inches wide and ½ inch thick. They are bent in a pear shape,
with the narrow ends fastened to the nave, and the crown resting upon
the rim of the wheel, where they are divided, and held in their places
by means of clip fastened with bolts. When the weight of the engine
comes on these spokes, those nearest the ground are compressed and
those, at the top are elongated a little. In order to avoid any of the
driving strain passing through the springs, a strong arm is fixed on the
differential wheel and attached to the rim as shown in Fig. 2, so that
the springs have really no work to do beyond carrying the weight of the
engine. Messrs. McLaren naturally felt a certain amount of diffidence
in placing their invention before the public until they had thoroughly
tested it in practical work. This, we are informed, they have done, with
the most satisfactory results, during the last five or six months; and
they have a set of springs which ran during that time between 2,000 and
3,000 miles, besides which there are several of these spring engines in
daily use.--_Iron_.
[Illustration: FIG 1. IMPROVED SPRING TRACTION ENGINE.]
[Illustration: FIG. 2]
* * * * *
TABLE SHOWING THE RELATIVE DIMENSIONS, LENGTHS, RESISTANCES, AND WEIGHTS
OF PURE COPPER WIRE.
DIAMETER | AREA
|
B.W.G Inch. Milli- | Circu- Square Square
No. metres | lar inches. Milli-
| Mils. metres.
|
0000 .454 11.5313 | 206116 .161883 10.4435
000 .425 10.795 | 180625 .141862 9.152
00 .38 9.6518 | 144400 .113411 7.3165
0 .34 8.6358 | 115600 .0907922 5.8573
1 .3 7.620 | 90000 .070686 4.5602
2 .284 7.2134 | 80656 .0633472 4.0867
3 .259 6.5784 | 67081 .0526854 3.3989
4 .238 6.0451 | 56644 .0444881 2.8701
5 .22 5.5879 | 48400 .0380133 2.4523
6 .203 5.1561 | 41209 .0323655 2.088
7 .18 4.5719 | 32400 .0254469 1.6417
8 .165 4.1909 | 27225 .0213825 1.3794
9 .148 3.7591 | 21904 .0172034 1.1098
10 .134 3.4035 | 17956 .0141026 .9096
11 .12 3.0479 | 14400 .0113097 .7296
12 .109 2.7701 | 11881 .00933133 .60199
13 .095 2.4129 | 9025 .0070882 .4573
14 .083 2.1082 | 6889 .00541062 .34906
15 .072 1.8288 | 5184 .00407151 .2486
16 .065 1.6510 | 4225 .00331831 .21407
17 .058 1.4732 | 3364 .0026421 .17045
18 .049 1.2446 | 2401 .00188574 .12165
19 .042 1.0668 | 1764 .00138544 .0894
20 .035 0.8890 | 1225 .000962115 .06207
21 .032 0.8128 | 1024 .00080425 .05188
22 .028 0.7112 | 784 .000615753 .03972
23 .025 0.635 | 625 .00049087 .03167
24 .022 0.5588 | 484 .000380133 .02452
25 .02 0.508 | 400 .00031416 .02027
26 .018 0.4571 | 324 .000254469 .01642
27 .016 0.4064 | 256 .000201062 .01297
28 .014 0.3556 | 196 .000153938 .00993
29 .013 0.3302 | 169 .000132732 .00856
30 .012 0.3048 | 144 .000113097 .007296