1. Field of the Invention
The invention relates to a rapid means of joining together two components as one so that relative motion in any direction is completely prevented. Although the invention may be applied to numerous situations where an effective joining is desired, it is particularly suitable for fastening together annular components, or cowlings, used in aircraft engine nacelles or pods, where the fastening must be not only reliable but also quickly executed.
2. Description of the Prior Art
For illustrative purposes, FIG. 1 shows a known type of turbojet by-pass engine. From upstream to downstream, referring to the direction of flow of gases shown by the arrow F1, such an engine schematically comprises a fan at 1 consisting of a low-pressure compressor which rotates within a first housing 2, one or more compressor stages at 3, a combustion chamber at 4, one or more turbine stages at 5 which drive the fan and the compressors, and an exhaust pipe at 6. The latter components are enclosed within a common cowling 7 which is made integral with the housing 2 of the fan. The operation of such an engine will not be described. It will merely be recalled that the fan 1 feeds air under pressure both to the compressor or compressors and around the cowling 7, the ratio of these two air flows being known as the motor dilution rate.
If it is to be installed on an airplane, the engine defined in this manner is enclosed in a nacelle which provides protection and channels the air. The engine suspension means are not a part of the invention and are not depicted. The nacelle comprises an air intake 8 which is an annular cowling connected at 9 to the upstream portion of the housing 2 of the fan 1, a two-part fan cowling 10 hinged, for instance, on the engine suspension device and affording access to various engine components, a rear cowling 11 which is also annular in shape and which is connected at 12 to the downstream portion of the housing 2 of the fan 1.
In the specific case chosen, the cowling 11 is mounted in a sliding fashion. That is, it is, for instance, installed so as to roll by means of roller wheels on tracks which are integral with the structure of the aircraft.
The air intake cowling 8 is generally made integral at 9 with the upstream portion of the fan housing 2 by means of a system of flanges secured by bolts. This arrangement is also generally used to join the rear cowling 11 at 12. The connection at 12 comprises, for example, a flange on the rear cowling which opposes a flange in the fan housing. Holes spaced at regular intervals on said flanges allow bolts to be inserted to effect the fastening; and means for centering and for angularly positioning the cowling 11 with respect to the flange of the housing 2 are provided, as well as means intended to absorb stresses exerted in the joining plane of the flanges and to prevent all relative movement in this plane. The latter may be the same as the former in certain cases. The bolts thus work solely in tension.
This traditional type of fastening by means of flanges and bolts is widely used by virtue of its simplicity of execution. Nevertheless, it requires a relatively long time for installation and removal of the cowling 11, due to the number of bolts and to the difficulty of access in large engines. Moreover, the fastening by means of bolts requires a certain number of precautions, in order to prevent premature opening as the result of vibrations, which also lead to a lengthening of the assembly and disassembly time.