M900 with M930 Charging Valve for single-hand operation
 | 1. Unattended Vehicle- (Parking Brakes Applied) |
Without pump pressure, the brake release valve stays in the SET position which connects brake to tanks and blocks all pressures from machine system hydraulics and the hand pump. This ensures that the unattended vehicle is parked.
| 2. Vehicle Startup- (Parking Brakes Remain Applied) |
When the pump on the machine is started, the Brake Tender senses the pressure and shifts the release mechanism, but stays in the SET position, which leaves the brake connected to the tank and blocks pressure from the machine's system hydraulics and hand pump so the machine remains parked.
| 3. Vehicle Tramming- (Parking Brakes Released) |
When the operator chooses to tram, he or she manually moves the brake release valve handle to the release position. This applies pressure to the brake cylinder and releases the brake, which is indicated on the gauge. Each time the hydraulic pressure in the charging valve falls below 85% of the set pressure, then the charging valve closes and recharges the accumulator which provides a constant standby of pressure to assure that the brakes remain fully released and do not drag on the brake disc while tramming. If the operator does not manually move the brake release valve handle to the release position, then any system hydraulic function may be used without releasing the brake. This satisfies paragraph b (5) The Automatic Emergency Parking Brake to "release only by a manual control that does not operate by any other equipment function."
| 4. Tramming Interuptions- (Brakes Applied and Released with Pump Running) |
When the operator moves the brake release valve handle to the SET position, the brake is applied immediately and remains set. It is not affected by any other on-board hydraulic functions being used.
| 5. Panic Bar Stops- (Parking Brake Applied by Panic Bar) |
When the brakes are released and the panic bar is activated, the linkage from the panic bar to the Brake Tender immediately moves the brake release valve to the SET position which applies the parking brake automatically.
| 6. Automatic Park Feature- (Parking Brakes Applied Automatically) |
Should the operator not apply the parking brakes manually when he turns off the vehicle, as the pump pressure decreases, the Brake Tender automatically moves to the SET position and the brakes are applied.
| 7. Tramming- (Primary Equipment Pump) |
The pressure created by the on-board pump shifts the lock mechanism which blocks pressure from the hand pump and will not allow the valve to shift to the hand pump. This allows the on-board pump to safely and completely override the Hand Pump.
| 8. Towing- (Hand-Pump-Created Brake Line Pressure) |
When the on-board hydraulics is shut off, the operator may move the brake release valve handle to the HAND PUMP position and pump the handle to the required pressure which is indicated on the gauge. This releases the brake for towing. The brake may be reset by moving the brake release valve handle to SET and lock out the hand pump circuit. This safely holds the machine in the parked position until the operator moves the brake release valve handle to release the brake as in step 2.
