Foundation Brake
Front Brake |
Y42.00-0047-01
Rear Brake |
Y42.00-0048-01
Working Principle-Foundation Brake
Construction Details
The ‘S’ cam brake is mainly used on commercial vehicles such as trucks, tippers and trailers. Brake shoes are actuated by camshaft which has “S” Cam Profile at its one end. And it is operated by slack adjuster and brake chamber on the other side. ‘S’ cam shaft is mounted with a bracket on the torque plate (Also called as brake carrier plate) with bush bearing support. The “S” Cam rotated by the auto slack adjuster moves the rollers apart which in turn expands the brake shoes against the brake drum. Auto brake adjustment is possible with the auto slack adjuster, thus compensating the brake-to-drum clearance at the time of lining wear. The slack adjuster is fitted to the splined end of the cam shaft.
The foundation brakes include two shoes with brake retractor springs and the fulcrum pins (Abutment end) on the other end of the brake shoe. The brake shoes are kept intact on its roller on one side and the fulcrum pins which is on the steel bushes over the torque plate. The rollers are allowed to roll on the ‘S’ cam profile during rotation of the camshaft. Hence it is reducing the friction and ensuring smooth transfer of force from the camshaft to brake shoe.
A shoe return spring is equipped between the shoe and the anchor pin that is fitted to a shoe web near the camshaft. Two shoe retracting springs are installed on a shoe rim hole near an abutment end. Two semicircular shields are utilized to cover the rear side of the brake assembly, thus protecting the brake components from dust.
Working Principle
When the brake pedal is pressed, high pressure air is passed into the brake chamber which in turn actuates the slack adjuster. This movement of slack adjuster actuates and rotates the “S” cam shaft. The rotation of “S” Camshaft moves the roller apart pushing the brake shoes against the brake drum. The friction surface of the brake shoe contacts with the brake drum and slows – stops the drum rotation
When the brake pedal is released, the air from the brake chamber is removed and the slack adjuster moves back. This ensures “S” Cam shaft to rotate back to its original position. The Shoe return spring pulls back the brake shoes to its original position, thus ensuring sufficient clearance between the brake shoe and the drum.
Brake System Circuit – Working Principle
Schematic Layout - Dual Circuit Air Brake System (8 X 4 WITH ABS) |
A | Air Compressor |
B | Air Processing Unit |
C | Four Circuit Protection Valve |
D | Auxiliary Tank |
E | Clutch Booster / Gear Box |
F | Diff Lock Magnetic Valve |
G | 1st Rear Axle Diff Lock |
H | 2nd Rear Axle Diff Lock |
I | Inter Axle Lock Magnetic Valve |
J | Inter Axle Lock |
K | Exhaust Brake Magnetic Valve |
L | Exhaust Brake |
M | Tipper or RMC |
N | Steering |
O | Hand Brake Valve |
P | ACRV |
Q | Automatic Slack Adjuster |
R | Spring Brake Actuator |
S | Brake Chamber |
T | Rubber Hose |
U | Relay Valve |
V | ABS Modulator |
W | DCV |
X | ASR |
Y | Modulator Module |
Z | Dual Brake Valve |
AA | Front Air Tank |
AB | Rear Air Tank |
AC | PLV |
Y42.00-0172-05
Schematic Layout - Dual Circuit Air Brake System (6 X 4 WITH ABS) |
A | Air Compressor |
B | Air Processing Unit |
C | PLV |
D | Supply Module |
E | Metering Unit |
F | Auxiliary Tank |
G | PRV |
H | Clutch Booster |
I | Diff Lock Magnetic Valve |
J | 1st Rear Axle Diff Lock |
K | 2nd Rear Axle Diff Lock |
L | Inter Axle Lock Magnetic Valve |
M | Inter Axle Lock |
N | Exhaust Brake Magnetic Valve |
O | Exhaust Brake |
P | Steering |
Q | Non Return valve |
R | Hand Brake valve |
S | ACRV |
T | Spring Brake Actuator |
U | Automatic Slack Adjuster |
V | ABS Modulator |
W | Relay Valve |
X | Brake Chamber |
Y | Rubber Hose |
Z | Dual Brake Valve |
AA | Front Air Tank |
AB | Rear Air Tank |
AC | Front Axle |
AD | First Rear Axle |
AE | Second Rear Axle |
Y42.00-0170-05
Schematic Layout - Dual Circuit Air Brake System (6 X 4 WITH ABS) |
A | Air Compressor |
B | Air Processing Unit |
C | Four Circuit Protection Valve |
D | NRV |
E | Gear Box Clutch Booster |
F | Auxiliary Tank |
G | 3/2 Magnetic Valve |
H | Constant Throttle Valve |
I | Diff Lock Magnetic Valve |
J | 1ST Rear Axle Diff Lock |
K | 2nd Rear Axle Diff Lock |
L | Inter Axle Lock Magnetic Valve |
M | Inter Axle Lock |
N | Exhaust Brake Magnetic Valve |
O | Exhaust Brake |
P | Steering |
Q | Hand Brake Valve |
R | ABS Modulator |
S | Relay Valve |
T | Spring Brake Actuator |
U | Automatic Slack Adjuster |
V | Quick Release Valve |
W | TCV |
X | Palm Coupling Supply |
Y | Palm Coupling Control |
Z | ACRV |
AA | Rubber Hose |
AB | Brake Chamber |
AC | Front Air Tank |
AD | Dual Brake Valve |
AE | Rear Air Tank |
AF | PLV |
AG | Front Axle |
AH | Second Rear Axle |
Y42.00-0173-05