9.96 
— ■ 173 — — 
20 for the number 
. 0.494 
re quu*ea on each side of the joint. 
W we use five rows and a pitch of 8^, tlio plates will have to be about 2’ long. 
Next come tho filling plates, the dimensions of which for the top cliovd we may 
av erageat^ x 12^ x 
Next come the jaw plates for the upper lateral struts. The greatest working 
stiess that could ever como upon one channel, under the supposition that it belongs to 
t，le triiiiS i is 1.8 x 2.013 = 3.G2 tons, the intensity being found from Table YIII. 
diameters and one eiul fixed. 
The thickness of jaw plate should be i", and the width, where the chord pin 
Passes tlu’ough, least 6" : it may be reduced to 4 : ,, where it is attached to the 
c 1 ‘ 飞 miels. Tj ie level* arm for tlie moment upon the rivets is 4(1 + i)= -h'\ mak- 
In S the moment Ä x 8.62 = 1.58 incli tons, which divided by 0.311, the resisting 
eudmg moment for a i ，r rivet, gives 6 as the number of rivets required. Of the 
【了 ets passing through both inner ancl outer jaw plates but one half the uumber should 
counted upon as acting, thus if three pass through but one jftw plate and six through 
J ’ the effective number will be six. 
Uis method of proportiouiug is, of course, not exact. Lotting the distance be- 
tween 
drawi 】 
叫 innei. faces of lateral struts channels be T f , we can determiue by making a 
8Ca l ö the length of the outer jaw plate to bo about three feet, and that of 
o r Ulüei one 江 bout two feet. The thickness of the latter need be only -V 1 and it« 
Ratest width at the hole, where the chord pin passes tlirougb, b fr . We can average 
° で th of the outer plate at 5" and tlie inner oue at ii f \ 
m ex t c °mo the jaw plates on the lower lateral struts. Those on the i ,r clianuel3 
be assumed without essential error to be of the same dimensions as those last 
eria ined. Those for the 5 ,r channel struts may be proportioned by taking the 
^elo 6S ^ S ^ l，ess that can come on tlio heaviest channel, under the supposition that it 
Tfihf S t0 t1ie "■»Wz. 2.63 x 2,5 = 6.58 tons, the intensity being found from 
ぞ 01 ’ 33 diameters and one end fixed. 
み e lever arm is i ( 舍 + i) = 長 ", leaking the moment upon the rivets 
.58 =5 2.88 inch tons, which divided by 0.311 determines tlio number to be 10. 
n ルレ case there is no inner jaw plate foi* the lateral rods are attached to ver- 
^Y e oiust test the assumed thickness for bearing. The greatest pull that 
_ — «*+4( 
tical pi ng# 
0 ^ e e ^ er c °me on the end lateral rod is (vide Table VI.) 29.789 + 4.128 = 83.867 
the . a f 0 f this, or about 17 tons is supported at each bearing. Tlxe diameter of 
,WaS P rev ^ ous ^y determined to bo Eeducing the 17 tons to 11.3 Ly 
As tf by 普 ， and consulting Table XV., we find the necessary beai’iug to be 金 ". 
thick 6 bears against both the channel web and the jaw plate, tlio assumed 
t*he t htter will be ample. Making a drawing to scale we can determine 
tlie な ) length of jaw plate to be about 4’. The width required at tho holes for 
rj „ 8 〇 1 ^° 一 18 ca n be determined as explained in Cliaptei. XIV. It will be about 
ふ ' 0 e ave ^age width may be assumed as 6.t 7/ * We can make the jaws for all the 
lanuel lateral struts of the same size. 
