NZ793272B2 - Steel pipe coupling device for steel pipes - Google Patents

Abstract

Coupling end-to-end steel pipes has challenges based on known methods such as welding steel pipes together at a construction site which requires skilled hands, and can be influenced by weather conditions. Furthermore steel pipe coupling devices are proposed which allow steel pipes to be connected together at a construction site without welding using screw based couples, however these are known to have strength limitations based on weak strength of screws. A coupling device (A) includes male and female couplings formed with first and second circumferential grooves (14 and 24) on surfaces of the respective couplings that face each other when the male and female couplings are fitted together. The coupling device (A) further includes an engaging member (30) configured such that, when the male coupling is pushed into the female coupling, the engaging member (30) is moved radially of the male and female couplings and retracted into the second groove (24), allowing the male coupling to be inserted into the female coupling, and when the male and female couplings are fitted together, the engaging member (30) is pushed radially into the first groove (14) by coil springs (34) so as to be fitted into both of the groove, thereby preventing separation of the male and female couplings in the axial direction. Countersunk head screws (41) support respective divided pieces (31) of the engaging member (30). Setscrews (44) are screwed in at ends of the divided pieces (31) that define boundaries between the adjacent divided pieces (31) to press the divided pieces against the bottom of the first groove. The engaging member is thus firmly fixed in position in the first and second grooves, thereby rigidly coupling the male and female couplings together in the vertical direction.

Claims (4)

What is claimed is:

1. A steel pipe coupling device for connecting opposed ends of two steel pipes to each other, the steel pipe coupling device comprising: a male coupling and a female coupling which are tubular in shape and configured to be welded to the respective steel pipes, the male and female couplings being further configured to be fitted to and engage each other in the direction of a common axis of the male and female couplings so as to be integrally rotatable about the common axis; wherein the male and female couplings have, respectively, circumferential grooves in peripheral surfaces thereof configured to be opposed to each other when the male and female couplings are fitted together such that the circumferential grooves are radially opposed to each other when the male and female couplings are fitted together; an engaging member configured to be fitted in both of the circumferential grooves so as to be movable radially of the male and female couplings when the circumferential grooves are radially opposed to each other, wherein the engaging member extends around an entire circumference of the male and female couplings, and is circumferentially divided into divided engaging pieces; wherein the male and female couplings are configured to be fitted to and mesh with each other with the female coupling located outside the male coupling, and the female coupling has through holes each located at a position corresponding to a respective one of the divided engaging pieces, and extending from an outer surface of the female coupling to the circumferential groove of the female coupling; push sticks each movably inserted through a respective one of the through holes and having a distal end thereof fixed to a respective one of the divided engaging pieces; wherein the steel pipe coupling device is configured such that the male coupling can be inserted into the female coupling by pulling out the push sticks until the divided engaging pieces are retracted into the circumferential groove of the female coupling, and such that, when the male and female couplings are fitted together, the male and female couplings can be coupled together so as to be inseparable in the direction of the common axis by pushing in the push sticks until the divided engaging pieces are fitted into both the circumferential grooves of the male and female couplings, and until heads of the push sticks are completely retracted into the respective through holes; and screws configured to be screwed into the female coupling from an outer surface of the female coupling to press ends of the divided engaging pieces that define boundaries between the adjacent divided engaging pieces so as to press the divided engaging pieces against an inner surface of the circumferential groove of the male coupling.

2. The steel pipe coupling device of claim 1, wherein springs are disposed on both sides of a fixed portion where the distal end of each of the push sticks is fixed to one of the divided engaging pieces at equal distances from the fixed portion, and between an outer surface of the divided engaging piece and a deeper inner surface of the circumferential groove of the female coupling, the springs being configured to press the divided engaging piece toward the male coupling.

3. The steel pipe coupling device of claim 1 or 2, wherein the male coupling has a first abutment edge, and the engaging member or each of the divided engaging pieces has a second abutment edge configured to abut the first abutment edge, wherein at least one of the first and second abutment edges has a chamfer.

4. The steel pipe coupling device of claim 1, substantially as herein described with reference to any embodiment disclosed.