| 摘要 |
1371311 Stranded cable SIEMENS AG 4 Jan 1973 [17 March 1972] 654/73 Heading H1A An SZ-stranded communications cable comprises a group of units stranded together, each of at least some of the units comprising insulated conductors stranded together and having sections of alternating directions of twist. The cable may also include sections of alternating twist of its units. The rate of lay and/or the frequency of alternation of twist direction may vary in any unit and between one unit and another. For any unit there are defined values d left and d right , and values a left and aright such that the pitch of lay in either direction is 1/d left on 1/d right , and the length of twist in either direction 1/2a left or 1/2a right . The values of d and/or the values of a vary along any unit so that the quantities (d left + <SP>a</SP> left ), (right + a right ), d left - a left ) and (d right - a right ) alternately increase and decrease in successive left-hand and successive right-hand sections by at least 0À5% from their respective mean values for that unit. Furthermore the mean values of (d left + a left ) and (d right + a right ) and/or the mean values of (d left - a left ) and (d right - a right ) for each unit differ from corresponding mean values for other such units, but in the case of at least one of said other units by not more than 10% of the mean values for that other unit. |
