TM-5-2330-378-14-P
SEMITRAILER, LOWBED: 40 TON CONSTRUCTION EQUIPMENT TRANSPORTER M870 AND M870A1
TECHNICAL MANUAL; OPERATOR'S, UNIT, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)
JUNE 1999
TM-5-2330-378-14-P - Page 26 of 524
TIVI5-2330-378-14&P
SectionIII. PRINCIPLESOF OPERATION
Paragraph
Page
Number
ParagraphTitle
Number
1-17
Airbrake System
..........................................................................................................................
1-12
1-18
Lighting System
..........................................................................................................................
1-15
1-17. AIRBRAKE SYSTEM.
The airbrake system of both the M870andthe
M870Al
semitrailers
consists of internal brakes, slackadjusters,
service
and emergency
airlines,
relayvalves,
multifunction valves, airreservoirs,
airbralke chambers, spring brakechambers,
and connections.
a.
INTERNAL BRAKES are located within the brakedrums.
Each internal brake has two brakeshoes
(1).
The outer
surfaces of the brakeshoes are fitted with brake linings.
Each brakeshoe is anchored at one
end on an anchor pin on which it pivots. The other end of each brakeshoe
is free to be pushed out or pulled
in.
b.
An S-SHAPED
CAM (2) on the end of the camshaft is mounted between the free ends of the two
brakeshoes(l). Rotation of the cam (2) forces the brakeshoes (1) out, causing the brake liningsto contact
the brakedrum.
c.
A BRAKESHOE
TENSION SPRING (3), near the free ends of the brakeshoes
(1), retractsthe
brakeshoes
(1) from the brakedrum
and holds them in a retracted position until the brakes are applied.
d.
SLACK ADJUSTER (4) is a lever mounted on the brake camshaft (5). Push rod (6) of the airbrake
chamber orthe spring brake chamber operates the slack adjuster (4); it in turn rotates the camshaft (5),
causing the cam (2) to press the brakeshoes against the brakedrum.
e.
AIRBRAKE
CHAMBERS
(7) are mounted to the rear axle internal wheel brakes. The airbrake chambers
convert air pressure into mechanical motion to operate the slack adjusters (4) when applying brakes.
7
6
4
5
2
3
1-12
Back to Top
