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TM-9-8240 12-Ton 4-Wheel Wrecklerlow-Bed Semitrailers M9 M270 and M270A1 Manual

Figure 16. Wheel brake mechanisn-semitrailers M270 and M269.

each

other

the

brake

drum

diameter

and

each

double-end wheel cylinder assembly is placed between

the toe of one brake shoe and the heel of the other

brake shoe.

Equal

hydraulic

pressure

thus

ap-

plied at each end of each shoe. Shoes are always

forward-acting,

independently

actuated

the

direc-

tion of drum rotation. Shoes are anchored at either

toe or heel, depending on the rotation of the drum.

(b)

When

the

brakes

are

applied,

the

wheel

cylinder

pistons

apply

equal

force

against

the

toe

and

heel

of each shoe. As the shoe linings come into contact

The ro-

with the drum, self-energization develops.

tation of the drum pulls the shoes against the drum

surface

augment

the

hydraulic

force

acting

the

shoes

and

produce

additional

braking

action.

(c)

The shoes are of the floating type, each being held

in position by a shoe guide pin, plain washer, C-

washer, and two brake shoe retracting springs. Each

short brake shoe retracting spring is hooked to the

anchor end of the brake shoe and to a projection

on the shoe anchor pin; each long brake shoe retract-

ing spring is hooked to the toe end of the brake shoe

and to a spring pin centered on the spider assembly.

(2) Semitrailers

M270

and

M269

(fig.

16).

(a) The

wheel

brake

mechanisms

are

located

within

the

TAGO 1321B