GB1303663A - - Google Patents

Abstract

1303663 Retractable undercarriage for aircraft MESSIER 30 Jan 1970 [31 Jan 1969] 4634/70 Heading B7G An undercarriage leg 1 is extendible and retractable under the control of a fluid-operated jack 2 and is braced in the lowered position (Fig. 1) by a strut comprising arms 3 and 4. The arm 4 is pivoted at 41 and carries a plate 5 having a cam slot 51 which controls, via arms 6 and 7, the position of slide 73 of fluid distributer 12 also interconnected via arms 7 and 9 with catch 8 which engages member 24 to lock the undercarriage when retracted. Door 16 of the undercarriage bay is opened and closed by fluid-operated jack 23, being locked when closed by the engagement of catch 17 and roller 19, and movement of the door controls, by means of arm 15 and cam slot 141 of plate 14 the position of slide 131 of fluid distributer 13 (see Fig. 7). When the undercarriage is locked down fluid is being fed under pressure to line X to enter distributer 12 (which is in the position shown in Fig. 4) at 122 and to be passed via cavity 1226 of the distributer to cavity 232 of jack 23 to maintain the door 11 closed; line Y is connected to a fluid reservoir. In this position of the door distributer 13 causes both sides of the jack 2 to be connected to vent line 138, Fig. 7, so that the undercarriage is not actuated. In order to raise the undercarriage line X is connected to the reservoir and pressure fluid is instead fed to line Y, to pass via cavity 1227 of distributer 12 to jack 20 to release the catch 17 and to cavity 233 of the jack 23 to open the door. As soon as it has opened beyond a certain angle, a new position of distributer 13 (Fig. 8, not shown) allows fluid to pass via channels 134 and 136 to the jack 2 so as to raise the undercarriage. This causes slide 73 to assume a first new position (Fig. 5, not shown), wherein the fluid is still fed to jack 23 so as to open the door, but at reduced pressure, via narrow channel 1218 and non- return valve 1219, and then a second new position (Fig. 6, not shown), wherein the fluid is fed from cavity 1226 to cavity 232 of the jack 23 so as to close the door. The pressure fluid also causes jack 24 to close the catch 8 as the undercarriage is raised, while spring 18 closes the catch 17. In order to lower the undercarriage the connection of lines X and Y is again reversed; catches 8 and 17 are disengaged by jacks 11 and 20, respectively, and the above-described sequence is reversed.