Releasable stop for a vehicle moving through a conduit

A releasable stop for releasably stopping a vehicle moving by air pressure through a conduit having an opening therein comprising,

• a stop gate pivotally supported at a point outside of said conduit for movement through said opening into and out of a position transverse to the path of movement of a vehicle in the conduit,
• first and second arms pivotally connected together by a first pivot connection, the first arm being pivotally connected to the gate by a second pivot connection, and the second arm being pivotally connected to a support by a third pivot connection, said first and second arms when aligned moving the stop gate to said position transverse to the movement of said vehicle and said aligned arms being positioned generally parallel to the path of movement of said vehicle for absorbing the impact of said vehicle,
• an air piston and cylinder assembly connected to one of the arms for moving said arms for rotating the stop gate into and out of the path of movement of a vehicle in the conduit, and
• coacting stop shoulders on the first and second arms for aligning the first pivot connection substantially in a dead center position with the second and third pivot connections when the stop gate is moved into the path of movement of a vehicle whereby the impact of a vehicle engaging the stop gate will be transmitted to the support instead of to the piston and cylinder assembly and said stop gate will be locked in the closed position,
• said gate, said first and second arms, and said piston and cylinder assembly are mounted on a movable support, and including,
• means connected to and yieldably resisting movement of said movable support when a vehicle engages said stop gate.