| 摘要 |
<p>799,029. Rod couplings. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. Oct. 29, 1956 [Oct. 31, 1955], No. 32955/56. Class 99(1). [Also in Group XXIV] In a pin-and-box coupling for a well-drilling string or drill casing, and in any section thereof containing the longitudinal axis of the coupling, a line 10 between the tip 6 of the extreme turn at one end of the screw-thread on the pin 1 and a point 11 on the longitudinal axis 3 of the coupling at which that axis is intersected by a line 9 which is an extension of the extreme inner flank 8 at the other end of the screw-thread on the pin, makes an angle of not more than 2 degrees with a line that is an extension of the extreme inner flank 7 at the said one end of the screw-thread on the pin. As shown, the pin and box are provided with tapered screw-threads and the line that is an extension of the flank 7 is coincident with the line 9. To engage the screwthreads the box is heated and shrunk on to the pin, or the pin is cooled and then allowed to expand in the box. Specifications 786,652 and 799,028 are referred to.</p> |
