Coupler for threaded reinforcing bar
A coupler including a fitting for mounting to externally threaded reinforcing bar for use in concrete construction, the fitting including a body having a portion with an internal thread for engagement with the thread of the reinforcing bar, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle.
1. A coupler comprising:
a fitting mountable to an externally threaded reinforcing bar, the fitting including a body having a portion having a first free end that defines an opening configured to receive the reinforcing bar and the portion having a second end spaced from the first free end, the body having an internal thread engageable with the thread of the reinforcing bar, the internal thread extending from the first free end of the portion to the second end of the portion, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle, wherein the first angle is constant throughout the internal thread from the first free end of the portion to the second end of the portion.
2. The coupler of claim 1 , wherein the outer ramped portion is arranged, such that on tightening threaded engagement of the reinforcing bar in the coupler, the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion.
3. The coupler of claim 2 , wherein the outer ramped portion is a straight line in cross-section.
4. The coupler of claim 1 , wherein the outer ramped portion is a straight line in cross-section.
5. The coupler of claim 1 , wherein the coupler is formed of a first component and a second component, the first component having a connecting part configured to connect the first component to the second component.
6. The coupler of claim 5 , wherein the second component is chosen from a set of interchangeable second components, each of the second components having a different form configured for a different purpose.
7. A kit for forming a coupler, the kit comprising:
a first component in the form of a fitting mountable to an externally threaded reinforcing bar, the fitting including a body having a portion having a first free end that defines an opening configured to receive the reinforcing bar and the portion having a second end spaced from the first free end, the body having internal thread engageable with the thread of the reinforcing bar, the internal thread extending from the first free end of the portion to the second end of the portion, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner portion,
the outer ramped portion being inclined to a central axis of the coupler at a first angle, wherein the first angle is constant throughout the internal thread from the first free end of the portion to the second end of the portion, wherein the externally threaded reinforcing bar is threaded into the internal thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread; and
a set of interchangeable second components configured to be interchangeably engaged with the first component.
8. The kit of claim 7 , wherein the set of interchangeable second components includes at least one of the following: a reinforcing bar joiner having an internal thread form the same as the thread form of the first component, a threaded insert, a flange nut and a metric joiner.
9. An assembly comprising:
an externally threaded reinforcing bar; and
a coupler including a fitting mountable to an externally threaded reinforcing bar, the fitting including a body having a portion having a first free end that defines an opening configured to receive the reinforcing bar and the portion having a second end spaced from the first free end, the body having an internal thread for engagement with the thread of the reinforcing bar, the internal thread extending from the first free end of the portion to the second end of the portion, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner ramped portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, the inner ramped portion being inclined to the central axis of the coupler at a second angle, the first angle being smaller in magnitude than the second angle, wherein the first angle is constant throughout the internal thread from the first free end of the portion to the second end of the portion,
wherein the externally threaded reinforcing bar is threaded into the internal thread of the coupler and tightened such that the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread.
10. An assembly comprising:
an externally threaded reinforcing bar; and
a fitting mountable to an externally threaded reinforcing bar, the fitting including a body having a portion having a first free end that defines an opening configured to receive the reinforcing bar and the portion having a second end spaced from the first free end, the body having an internal thread for engagement with the thread of the reinforcing bar, the internal thread extending from the first free end of the portion to the second end of the portion, wherein the internal thread has an asymmetric thread form having an outer ramped portion and an inner portion, the outer ramped portion being inclined to a central axis of the coupler at a first angle, wherein the first angle remains constant throughout the internal thread from the first free end of the portion to the second end of the portion,
wherein the externally threaded reinforcing bar is threaded into the internal
thread of the coupler and tightened such that the external thread of the reinforcing bar is securely engaged in contact with the outer ramped portion of the internal thread.
11. The assembly of claim 10 , wherein the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread.
12. The assembly of claim 11 , wherein an outer rib of the external thread of the reinforcing bar is engaged in continuous line contact with the outer ramped portion of the internal thread.
13. The assembly of claim 12 , wherein the coupler has an internal stop against which an end of the reinforcing bar abuts to facilitate engagement of the external thread of the reinforcing bar with the outer ramped portion of the internal thread.