Couplings for concrete reinforcement bars

A three-piece splice between adjacent ends of two structural reinforcement bars for embedding in poured concrete construction, each bar having a cylindrical body of nominal diameter with raised deformations on said body intermediate two opposite ends, comprising:

• each of said adjacent ends having an end segment of enlarged diameter relative to said nominal diameter, a male thread on said segment characterized in that the bottom of said threading has a thread diameter intermediate said nominal diameter and the maximum diameter of said deformations thereby to preserve the tensile strength of said reinforcement bar;
• coupling sleeve open at opposite ends and internally threaded continuously between said ends for mating with said male thread, said sleeve being substantially longer than said end segment of enlarged diameter;
• at least one of said bars characterized in that said deformations within a region immediately adjacent to said end segment are compressed to a flattened condition of reduced maximum diameter lesser than said thread diameter without substantial reduction in total cross-sectional area of said body to allow said coupling sleeve to be threaded entirely onto said end segment and over said compressed deformations of said least one bar without interference between said internal thread and said flattened deformations.

A three-piece splice between adjacent ends of two structural reinforcement bars for embedding in poured concrete construction, each bar having a cylindrical body of nominal diameter with raised deformations on said body intermediate two opposite ends, comprising:

• each of said adjacent ends having an end segment of enlarged diameter relative to said nominal diameter immediately adjacent to a diametrically unenlarged portion of said body, a male thread on said segment characterized in that the bottom of said thread has a diameter at least equal to the maximum diameter of said deformations thereby to preserve the tensile strength of said reinforcement bar;
• a coupling sleeve open at opposite ends and internally threaded continuously between said opposite ends for mating with said male thread, said sleeve being substantially longer than said end segment of enlarged diameter;
• whereby said coupling sleeve can be advanced past said end segment and onto said unenlarged portion of said body.