Self-gripping, no-slip rebar coupler

1 . A rebar coupler comprising:

first and second threaded housing components configured to be threaded together by applying rotational torque;

a central positioning element configured to provide a stop for inserted rebar pieces;

first and second sets of tapered gripping members, each set comprising a plurality of wedges configured to grip rebar through wedge action against tapered surfaces;

an internal structural element positioned between the first and second threaded housing components and configured to prevent direct contact between the first and second threaded housing components while creating opposing force that locks the tapered gripping members against inserted rebar pieces when the threaded housing components are tightened together;

wherein the means for creating opposing force comprises the internal structural element configured to apply outward force upon the tapered gripping members when contacting the tapered gripping members, or the central positioning element configured to constrain inserted rebar pieces such that tightening of the threaded housing components applies force upon the constrained rebar pieces which transmit opposing force to the tapered gripping members;

wherein the rebar coupler is configured to accommodate rebar sizes ranging from #4 nominal rebar to #11 nominal rebar without modification, and

wherein the coupling is achievable by a single person using hand-operated rotational tightening tools, including pipe wrenches, without requiring impact wrenches, pneumatic torquing tools, threading machines, or hydraulic swaging equipment.

2 . The rebar coupler of claim 1 , wherein the means for creating opposing force comprises an internal structural element that prevents direct contact between the first and second threaded housing components.

3 . The rebar coupler of claim 1 , wherein the central positioning element is configured such that rebar pieces inserted from opposite ends contact the central positioning element to establish proper positioning.

4 . The rebar coupler of claim 1 , wherein the tapered gripping members are configured to convert axial tightening force into radial gripping force on inserted rebar pieces.

5 . The rebar coupler of claim 1 , further comprising at least one spring providing initial outward force on the tapered gripping members.

6 . The rebar coupler of claim 1 , wherein the first and second sets of tapered gripping members each comprise an elastic support ring maintaining the gripping members in an assembled state.

7 . The rebar coupler of claim 1 , wherein the first and second threaded housing components each comprise a tapered bore with a tapering angle between 0.1 and 89.9 degrees, and wherein the tapered bore corresponds to the taper of the wedges.

8 . A method of coupling rebar comprising:

inserting first and second pieces of rebar into opposing ends of a field-installable coupler until each piece contacts a central positioning element;

applying torque to threaded components of the coupler by rotating the threaded components using pipe wrenches or similar hand-operated rotational tightening tools to create gripping force on the rebar pieces through a plurality of tapered wedge action comprising tapered gripping members acting through tapered wedge action against tapered bores; and

achieving a secure, slip-resistant connection that meets structural engineering standards without requiring impact wrenches, pneumatic torquing tools, threading machines, or hydraulic swaging equipment or rebar end preparation;

wherein the method accommodates rebar sizes from #4 to #11 nominal rebar and is performable by a single person; and

wherein the threaded components are tightened together such that an internal structural element positioned between the threaded components creates opposing force that prevents direct contact between the threaded components while locking the tapered gripping members against the inserted rebar pieces,

wherein the opposing force is created by the internal structural element applying outward force upon the tapered gripping members when contacting the tapered gripping members, or by the central positioning element constraining the inserted rebar pieces such that tightening force is transmitted through the constrained rebar pieces to the tapered gripping members.

9 . The method of claim 8 , wherein one or more elastic support rings maintain a plurality of wedges comprising tapered gripping members in proper radial alignment throughout the coupling process, and wherein the elastic support rings are positioned in circumferential grooves on exterior aspects of the wedges.

10 . The method of claim 8 , wherein the one or more springs provide initial positioning force that seats the tapered gripping members comprising a plurality of wedges against tapered bores of threaded external housings; and

wherein the one or more springs continue to exert outward force on the tapered gripping members during tightening of the threaded components.

11 . A field-installable rebar coupler comprising: first and second threaded housing components configured to be threaded together by applying rotational torque; a central positioning element configured to provide a stop for inserted rebar pieces; first and second sets of tapered gripping members, each set comprising a plurality of wedges configured to grip rebar through wedge action against tapered surfaces; and an internal structural element positioned between the first and second threaded housing components and configured to prevent direct contact between the first and second threaded housing components while creating opposing force that locks the tapered gripping members against inserted rebar pieces when the threaded housing components are tightened together, wherein the internal structural element is configured to apply outward force upon the tapered gripping members when contacting the tapered gripping members, or the central positioning element is configured to constrain inserted rebar pieces such that tightening of the threaded housing components applies force upon the constrained rebar pieces which transmit opposing force to the tapered gripping members, and one or more elastic support rings maintaining the plurality of wedges in each set of tapered gripping members in radial alignment; wherein the rebar coupler is configured to accommodate rebar sizes ranging from #4 nominal rebar to #11 nominal rebar without modification, and wherein the coupling is achievable by a single person by rotating the threaded housing components using pipe wrenches or similar hand-operated rotational tightening tools without requiring impact wrenches, pneumatic torquing tools, threading machines, or hydraulic swaging equipment or rebar end preparation; and wherein the rebar coupler is configured to eliminate slip between coupled rebar pieces to meet CalTrans CT670 test requirements through continuous force application by the internal structural element during tightening.

12 . The rebar coupler of claim 11 , wherein the means for creating opposing force comprises an internal structural element that prevents direct contact between the first and second threaded housing components.

13 . The rebar coupler of claim 11 , wherein the central positioning element is configured such that rebar pieces inserted from opposite ends contact the central positioning element to establish proper positioning.

14 . The rebar coupler of claim 11 , wherein the tapered gripping members are configured to convert axial tightening force into radial gripping force on inserted rebar pieces.

15 . The rebar coupler of claim 11 , wherein the rebar coupler is configured to minimize slip between coupled rebar pieces to meet CalTrans CT670 test requirements.