Locking device and method for securing telescoped pipe

Abstract

A locking segment for use in connecting two lengths of pipe has a radically extending heel that serves as a rotational brake. By mating the brake into an annular trough, that is, by placing it between two walls, the rotation of the segment can continue only until points on the brake mure between the two walls. Rotation of the segment in response to increasing thrust pressures can thereby be arrested before the rotation causes the segment to bear on the spigot with a radially inward force great enough to penetrate the spigot.

We claim:  
     
         1 . A joint for pipes comprising a bell, a spigot partially disposed within the bell, a locking segment disposed between the bell and the spigot, and a retainer capable of holding said locking segment in the bell during assembly, wherein said locking segment is adapted to rotate in the absence of a fixed axis of rotation into locking engagement between the bell and the spigot in response to movement of the spigot outward of the bell, and wherein further the locking segment is adapted to resist rotation in response to said outward movement beyond a desired maximum rotation by muring between a first surface of the bell and a second surface of the bell, and wherein further the segment is adapted to resist rotation beyond a desired limit of rotation in an opposite direction by muring within the bell.  
     
     
         2 . A method of controlling radial pressures exerted between a bell and a spigot in a joint comprising the steps of 
 a. Placing the segment within the bell, and    b. Rotating the segment against a fulcrum on the interior of the bell such that a radially inward portion of the segment rotates in the axially inward direction,    c. increasing radial forces between the bell and the spigot primarily by rotating the locking segment about a different axis than the fulcrum, and    d. muring a portion of the segment between two surfaces of the bell, whereby further rotation of the segment is arrested.    
     
     
         3 . A gasket for use in connecting a spigot within a bell having an annular trough for receiving a portion of the gasket, the gasket comprising a sealing portion, a retainer heel adapted to mate with the annular trough, and a locking segment comprising a brake and a toe, the toe having a tooth capable of penetrating into the spigot, the brake being disposed at least partially within said retainer heel, such that when said retainer heel is placed in the annular trough at least a portion of the brake is disposed within the annular trough, which brake possesses at least two points separated by a distance greater than the width of the annular trough, such that upon a maximum rotation a first of the at least two points resistively meets a first wall of the annular trough while a second of the at least two points resistively meets a second and opposing wall of the annular trough, such that rotation is arrested, and wherein further the brake aids in retention of the heel in the annular trough during insertion of the spigot into the bell.