一 171 — 
P Q- Let ns assume that the vertical distance between the centre of the pin hole 
a ^d the bottom of the shoe plate and that from the centre of a pin hole to the bot- 
tom of a post are each ten inches. Subtracting V r for the thickness of the slioe 
plate, let us lay off the remaining 9" perpendicular to C D and E F so as to deter- 
mine the centres of the pin holes. Laying off tho limiting circle of rivets with an 
assumed radius of BJ^, we can raark the rivet centres as in the diagram ami 
^etermiue the height of G Z above C D to be 22i". If from Z we drop tlie porpen- 
对 。 U ^ ^ to A B and thus determine the base of tlie bent plate to be C D i E ''e 
u t け cnU 0 f proportion and probably too large. Let us see if it be so* The 
a est pressure on a leeward shoe is 
早 nn + , 10 . 7= about 78 tons. 
Tabl^ 6 ^ 118 assume the length of each roller to be 20^ and the diameter 2|", tlien 
te 6 WH. gi ves tlie permissible pressure as 7.91 tons, which divided into 78 gives 
tlie number of rollers required. 
出 ^°wing a space of 1’’ between rollers and a play of three inches would make 
ass OM of shoe plate 37". This is out of proportion to the width, so let us 
a uew width of 25 f, and try again. The last mentioned table gives the per- 
e i ぶ 6 P re S3ure on a roller 2 表 " x 25" as 9.88 tons, which divided into 78 gives 
o ^ as the number required, making the length of shoe plato 80". This is a better 
slla Pe and will therefore bo adopted. 
C E . 】 l 0W i n g 山〇 shoe plate and the batter brace upper plate to project 3" beyond 
tl J ln the dia P.am, will leave が to be laid off from C E to the riglit hand edge of 
Y jj S p G B S. We can now join R T and S U, and determine G Z T R S TJ 
Uxr ^ G to be the development of tlie bent connecting plate. Its dimensions are 
aV6ra f d the bill of material. 
t ftom K we measure the perpendicular to C G, we find it to be about 
