Stop knob for vehicle air brake

An air valve assembly comprising:

• one or more first fluid ports and one or more second fluid ports;
• a valve, configured to fluidly connect or fluidly disconnect the one or more first ports with the one or more second ports;
• an actuating arm that is coupled to the valve, wherein in response to displacement of the actuating arm satisfying a threshold distance, the valve is moved to a first position, and in response to displacement of the actuating arm not satisfying the threshold distance, the valve is moved to a second position;
• and
• a locking knob, comprising:
• a push rod comprising
• a knob head at a first end of the push rod,
• first thread along an exterior surface of the push rod, and
• a cavity within the push rod exposed at a second end of the push rod opposite of the first end, the cavity configured to house the actuating arm of the air valve assembly that is held fixed to the push rod;
• and
• a locking ring comprising
• a ring-shaped body with a channel that is configured to house the push rod, and
• second thread within the channel that is configured to mate with the first thread,
• wherein rotation of the locking ring in a first direction moves the locking ring toward the second end of the push rod which restricts travel of the push rod and the actuating arm of the air valve assembly by a threshold amount to prevent the valve from moving from the second position to the first position.

A vehicle, comprising:

• a pneumatic air brake;
• a fluid pressure source;
• and air valve assembly, fluidly connected between the fluid pressure source and the pneumatic air brake through one or more fluid lines, the air valve assembly comprising:
• one or more first fluid ports fluidly connected to the fluid pressure source and one or more second fluid ports fluidly connected to the pneumatic air brake;
• a valve, configured to fluidly connect or fluidly disconnect the one or more first ports with the one or more second ports;
• an actuating arm that is coupled to the valve, wherein in response to displacement of the actuating arm satisfying a threshold distance, the valve is moved to a first position to disengage the pneumatic air brake, and in response to displacement of the actuating arm not satisfying the threshold distance, the valve is moved to a second position to engage the pneumatic air brake;
• and
• a locking knob, comprising:
• a push rod comprising
• a knob head at a first end of the push rod,
• first thread along an exterior surface of the push rod, and
• a cavity within the push rod exposed at a second end of the push rod opposite of the first end, the cavity configured to house the actuating arm of the air valve assembly that is held fixed to the push rod;
• and
• a locking ring comprising
• a ring-shaped body with a channel that is configured to house the push rod, and
• second thread within the channel that is configured to mate with the first thread,
• wherein rotation of the locking ring in a first direction moves the locking ring toward the second end of the push rod which restricts travel of the push rod and the actuating arm of the air valve assembly by a threshold amount to prevent the valve from moving from the second position to the first position.