Abstract The invention discloses a modulator for use with an air brake system with an anti-skid device, which modulator comprises, in general, a solenoid controlled two port connection valve, a passage with a restrictor bypassing the two port connection valve, and a solenoid controlled three port connection valve whose intake port is communicated with both the outlet ports of the two port connection valve and the bypass passage. When no control signal is received from an computer when a brake pedal is depressed, the compressed air flows through both the two port connection valve and the bypass passage into the three port connection valve so that the actuator pressure may be increased at a faster rate in order to compensate the time lag until the actuator pressure reaches a predetermined level immediately below the set point at which the computer generates the pressure release signal. When the actuator pressure reaches the predetermined level, the computer generates the throttle signal in response to which the two port connection valve is closed so that only a small quantity of compressed air flows through the bypass passage into the three port connection valve. Thus the actuator pressure may be increased at a slow rate in order to minimize the overshooting which results in dangerous skidding. After the actuator pressure exceeds the set point, the three port connection valve is so actuated as to release the actuator pressure into the surrounding atmosphere in a conventional manner.
A modulator for use with an air brake system with an antiskid device comprising a. a solenoid controlled two port connection valve (13) in which a valve rod (16) which is carried by an upper diaphragm (17) and a lower diaphragm (18) vertically spaced apart from each other by a predetermined distance, provided with a valve member (19) interposed between said upper and lower diaphragms, and is biased in the axial direction thereof under the force of a bias spring (24), is made into engagement with a plunger coaxially thereof of a solenoid coil (22); b. a bypass passage (28) with a restrictor (15) for bypassing said two port connection valve by intercommunicating between an intake port (25) and an outlet port or passage (26) of said two port connection valve; and c. a solenoid controlled three port connection valve (14) in which a valve rod (30) with a valve (35) interposed between an upper valve seat (37) and a lower valve seat (38) is carried by a diaphragm (31) and is biased in the axial direction thereof under the force of a spring (32) so as to be made into engagement with a plunger of a solenoid coil (33), whereby when said valve (35) is displaced, the communication among an outlet port (39), said passage (26), and a discharge port (40) may be established or interrupted.
Claim 2
Dependent Claim
227 words
A modulator for use with an air brake system with an antiskid device comprising a. a solenoid controlled two port connection valve (13) in which a valve rod (16) which is carried by an upper diaphragm (17) and a lower diaphragm (18) vertically spaced apart from each other by a predetermined distance, provided with a valve member (19) interposed between said upper and lower diaphragms, and is biased in the axial direction thereof under the force of a bias spring (24), is made into engagement with a plunger coaxially thereof of a solenoid coil (22); b. a bypass passage (28) with a restrictor (15) for bypassing said two port connection valve by intercommunicating between an intake port (25) and an outlet port or passage (26) of said two port connection valve; and c. a solenoid controlled three port connection valve (14) in which a valve rod (30) with a valve (35) interposed between an upper valve seat (37) and a lower valve seat (38) is carried by a diaphragm (31) and is biased in the axial direction thereof under the force of a spring (32) so as to be made into engagement with a plunger of a solenoid coil (33), whereby when said valve (35) is displaced, the communication among an outlet port (39), said passage (26), and a discharge port (40) may be established or interrupted.