Automatic shut-off valve

An automatic shut-off valve for a straight walled fluid carrying pipe that is connected to a breakable control device comprising:

• a downstream mounting ring having a central hole therein held inside the straight walled pipe with attaching means,
• an upstream mounting ring having a central hole therein held inside the straight walled pipe with attaching means spaced apart from the downstream mounting ring,
• a cylindrical rod having a rigid portion and a frangible end with the frangible end retained by the breakable control device attached to the fluid carrying pipe, and the rigid portion slidably disposed within the central hole of the mounting ring,
• a restricting disc having a centrally located penetration and opposed radial indentations permitting the disc to nest essentially onto the rod when inserted thereon through the penetration, and rotate in one direction from parallel with the pod to a position 90 degrees therefrom until the opposed radial indentations embrace the rod and restrict further rotation, said disc further having link means connected to a upstanding pivot mount for rotation of the disc,
• a hollow spacer sleeves having opposed disc retainers attached thereto, disposed upon the rod contiguous with the downstream mounting ring and through the restricting disc constituting a pivotal restriction for the disc,
• a hub fixably attached upon the rod having an integral protruding finger attached to the link means of the disc, rotating the disc 90 degrees when the hub is moved away from the upstream mounting ring, and
• a compression spring surrounding the rigid portion of the rod between the downstream mounting ring and the hub such that when the breakable control device is broken off the frangible end is disconnected permitting the link means to rotate the disc to a restricting position under the urging of the spring shutting off fluid flow within the fluid carrying pipe in which the shut-off valve is mounted.