Method of working connection end of deformed bar for reinforcing concrete, deformed bar worked by the method and structure of connecting deformed bar

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(11)

EP 0 947 642 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	12.01.2000 Bulletin 2000/02

(43)	Date of publication A2:
	06.10.1999 Bulletin 1999/40

(21)	Application number: 99302528.7

(22)	Date of filing: 31.03.1999

(51)	International Patent Classification (IPC)⁷: E04C 5/16, E04C 5/03, B21B 1/16

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

31.03.1998 KR 9811278

(71)	Applicant: Chung, Gyeng Ok
	Kumcheon-ku, Seoul 153-039 (KR)

(72)	Inventors:
	Chung, Gyeng Ok Seoul (KR) Yoo, Chung Ki Dongdaemoon-Ku, Seoul (KR)

(74)	Representative: Downey, William Gerrard et al
	Wilson, Gunn, M'Caw, 41-51 Royal Exchange, Cross Street Manchester M2 7BD Manchester M2 7BD (GB)

(54)	Method of working connection end of deformed bar for reinforcing concrete, deformed bar worked by the method and structure of connecting deformed bar

(57) With an object of providing a method of working a connection end portion of deformed bar for reinforcing concrete considerably reducing working expense by enhancing easiness of working by promoting mechanical strength of a connection portion by being able to work the connection portion without destructing a steel skeleton structure of a connection portion between pieces of steel bar, deformed bar worked by the method and a connection structure of deformed bar, the invention provides a method of working a connection end portion of deformed bar for reinforcing concrete featured in comprising a swaging step in which in deformed bar for reinforcing concrete featured in swaging at least a connection end portion at normal temperature and forming a rolled thread portion at an outer peripheral face of the connection end portion of the deformed bar subjected to the swaging step in which at least one connection end portion is swaged at a normal temperature such that a maximum diameter of the connection end portion is equal to or slightly larger than a diameter of a cylindrical body of the deformed bar or slightly smaller than a diameter of the deformed bar depending on a degree of working; and
a rolling step of forming a thread portion having a diameter substantially equal to a swaging diameter at an outer peripheral face of the connection end portion of the deformed bar which has been subjected to the swaging step.

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