Coupling having seal with retracting center leg
A coupling for joining pipe elements has segments surrounding a central space with cusps which engage lobes of a seal to maintain the segments in spaced apart relation in a preassembled state. While the coupling is in the preassembled state the pipe elements may be inserted into the central space without disassembling the coupling, and portions of the seal adjacent to attachment members on the segments seat within a channel defined by the segments between the cusps. When the seal is compressed between the segments and the pipe elements to form a joint the seal deforms so as to withdraw a center leg of the seal from the flow path defined within the pipe elements.
1. A method of maintaining first and second segments of a coupling in spaced relation in a preassembled state to permit pipe elements to be inserted into a central space surrounded by said segments when said segments are attached end to end, said method comprising:
positioning a seal within said central space, said seal having first and second lobes positioned on opposite sides thereof;
contacting said first lobe with a cusp of a first shoulder of said first and second segments at first and second points between ends of said first and second segments and contacting said second lobe with a cusp of a second shoulder at first and second points between ends of said first and second segments;
contacting said first lobe with a surface of said first shoulder of said first and second segments at points proximate said ends of said first and second segments and contacting said second lobe with a surface of said second shoulder of said first and second segments at points proximate said ends of said first and second segments.
2. A method of connecting first and second pipe elements to one another using a coupling comprising first and second segments attached to one another end to end surrounding a central space, a seal being positioned between said segments, said seal comprising first and second lobes on opposite sides thereof and a center leg positioned between said lobes, said center leg projecting toward said central space, said method comprising:
supporting said segments in spaced apart relation on said seal by contacting first and second points on said first lobe with first cusps of first shoulders of said first and second segments, said first and second points on said first lobe being between ends of said first and second segments, and by contacting first and second points on said second lobe with second cusps of second shoulders of said first and second segments, said first and second points on said second lobe being between ends of said first and second segments;
inserting said pipe elements into said central space, said center leg being between said pipe elements;
drawing said first and second segments toward one another and thereby deforming said seal such that said center leg is retracted in a direction away from said central space.