1、O O O a CEN PREN*374L 93 m 3404589 0043263 bLb m AECMA STANDARD NORME AECMA AECMA NORM prEN 3741 Edition P 1 March 1993 EDITE PAR LASSOCIATION EUROPEENNE DES CONSTRUCTEURS DE MATERIEL AEROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1) 47.36.98.76 U
2、DC : Descriptors : ENGLISH VERSION Aerospace series Nuts, clip, metric Installation holes and assembly Srie arospatiale crous pincer, mtriques Trous dinstallation et montage Lut- und Raumfahrt Klemmuttern, metrisch Einbaulcher und Montage This “Aerospace Series Prestandard has been drawn up under th
3、e responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the
4、publication of this prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the
5、 Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. Nota - Extra copies can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISSY-LES-MOULINEAUX CEDEX C8 Chairm
6、an I Comments should be sent within six months after the date of publication to I Edition approved for publication Mr. WILLIAMS AECMA Technopolis - 175, rue Jean-Jacques Rousseau 921 38 Issy-les-Moulineaux Cedex - FRANCE 1993-03-25 aecma 1993 CEN PRENx3741 93 3404589 O043262 552 = 1 prEN 3741 Page 3
7、 1 Scope This standard specifies the characteristics of the installation holes required for the utilization of clip nuts with design configuration to EN-Standards for aerospace applications. 2 Normative references EN 3726 Aerospace series - Nuts, self-locking, clip, in heat resisting steel FE-PA92HT
8、 (A286), Mos2 coated - Classification : 1 100 MPa (at ambient temperature) / 425 OC 3 Principle The self-locking clip nuts are parts held in place on their support by the elastic action of the nut cage. A centering piece located on the tab of the cage ensures the correct installation of the clip nut
9、 Self-locking is ensured by the distortion of the last nut end threads. See figure 1. Figure 1 11 Published as AECMA Prestandard at the date of publication of this standard piece Previous page is blank CEN PRENx374L 93 D 3404589 0043263 499 Diameter Thread C D code prEN 3741 Page 4 4 Design instruc
10、tions 4.1 Support design 4.1.1 Installation A : “on flank of support“ See figures 2 and 3. E I OD 040 Figure 2 3 MJxO, - 4H6H 4.1.2 Installation B : “with slot“ 050 O60 See figures 4 and 5. 1) r / 7,s 8t6 19,5 9,1 MJ50,8 - 4H6H 9,5 MJ6xl -4H5H 1 F, or F, 1) Minimum zone allowing the passage of the t
11、abs depending of the mounting face (see figure 5). All the shapes capable of enveloping this minimum zone are acceptable. Figure 4 4.1.3 Dimensions See table 1. Table 1 I I f0,25 I I min. I I I 7 I Figure 3 I- - -I Figure 5 Dimensions in millimetres sul: thicl F, l) F, l) 16 Ort ess min. - 019 1See
12、figures 4 and 5. CEN PREN*374L 93 m 3404589 00432b4 325 m prEN 3741 Page 5 4.2 Type of installation 4.2.1 Installation A - install the clip nut on the edge of the support ; - apply pressure on the cage as illustrated on figure 3, until the centering piece clears the edge of the support ; - push the
13、clip nut until the centering piece locates in the hole. 4.2.2 Installation B In the case of assembly on inner panels : - slide the cage through the support access hole, as illustrated on figure 5 ; - proceed until the centering piece locates in the hole. 5 Indication on drawings 5.1 Definition drawi
14、ng See example on figure 6. 1) way of assembly 5.2 Assembly drawing See example on figure 7. /EN3741 -050A Figure 6 I / Clip nut EN3726-050 Assembly EN3741 Figure 7 CEN PRENt374L 93 m 3404589 0043265 261 m prEN 3741 Page 6 6 Designation EXAMPLE : Identity block Number of this standard Diameter code (see table 1) Type of installation (see 4.2)
