Truck-mounted brake system
A truck mounted braking system is provided with a mechanical pivot adjustment on a lever connected to the brake actuator to permit the braking force applied to the wheels to vary depending on the lading condition of the car, without involving additional pneumatic elements such as a pneumatic empty load device. The system adjusts the braking force applied when the hand brake is activated, even when the railway car is disconnected from the pneumatic brake line.
1. A truck-mounted braking system for a railway car, comprising,
a first brake beam and a second brake beam separated along a longitudinal axis of the railway car, the first and second brake beams each having a compression member and a tension member, and a respective first and second strut attached between the respective compression member and tension member;
a brake actuator;
a brake actuator lever connection operatively connected to the brake actuator and adapted to move linearly in response to the brake actuator;
a live lever pivotally attached to the first strut on the first brake beam by a pin, pivotally attached to the brake actuator lever connection, and pivotally attached at an end of the live lever to a slack adjuster;
a dead lever, pivotally attached to the second strut on the second brake beam, pivotally attached at one end to said slack adjuster, and pivotally attached at an end opposite said one end, directly or indirectly, to the brake actuator; and
a pivot adjustment hole in the live lever that receives the pin in at least two different positions in the hole, corresponding to at least two lading conditions of the railway car;
wherein the pivot adjustment hole is a crescent-shaped aperture adapted to accommodate the pivot pin in said at least two positions at two opposed ends of the pivot adjustment hole.
2. The truck mounted braking system according to claim 1 , wherein the live lever has a hand brake connection at one end adapted for mechanical connection to the hand brake.
3. The truck-mounted braking system according to claim 2 , wherein the hand brake connection has a raised height relative to the pivot adjustment hole.
4. The truck-mounted braking system according to claim 1 , wherein an end of the live lever opposite the slack adjuster is angled away from a line drawn through the brake actuator lever connection and the attachment of the lever to the slack adjuster.
5. The truck-mounted braking system according to claim 1 , further comprising a sensor detecting the at least two lading conditions of the railway car, the sensor mounted to the railway car truck and mechanically connected to the live lever.
6. The truck-mounted braking system according to claim 5 , wherein the sensor is mounted to a railway car bolster, and a lever on the sensor contacts a point on the side frame to detect a lading condition of the railway car.
7. The truck-mounted braking system according to claim 5 , further comprising an output arm on the sensor having a rigid attachment to the live lever proximate the pivot adjustment hole, said attachment adapted to move the position of the pivot adjustment hole in tension and compression.
8. The truck-mounted braking system according to claim 1 , wherein the slack adjuster includes a housing and a pawl box removably and mechanically mounted on the housing.