FR2683580A1 - Safety locking device with a swinging hook - Google Patents

Abstract

It includes a first hook (2) mounted so that it overhangs on a swing pin (3) in order to support a fastening member (8) bearing on a retractable locking member (30) opposing a swinging movement of the first hook, and a second hook (5) adjacent to the first hook and connected to a connection member (45) so that in the position in which the first hook is closed, the second hook (5) has a fastening edge (47) set back from the fastening edge (46) of the first hook and a part (29) for bearing on the locking member (30) set back with respect to a bearing part (12) of the first hook.

Description

 The present invention relates to an alternative embodiment of the safety locking device with tilting hook of French patent application 91 11812 of September 25, 1991.

 Locking devices are known comprising a housing, a hook mounted in a cantilever fashion for tilting about a tilting axis carried by the housing, and a retractable locking member intended to oppose a tilting movement of the hook when this one is in charge. This type of locking device is used in particular to lock a door or a shutter in the closed position. In certain cases, in particular when the device is used to lock thrust reversing flaps of the engines of an airplane, it is necessary that the locking be provided in a particularly safe manner since a failure of the locking device would have extremely serious consequences. In particular, in the case of thrust reversing flaps of an airplane's reactors, an untimely opening of these flaps in flight or in a landing phase before taxiing on the ground causes such a braking pulse on the plane that control of it is irretrievably lost.

 In the aforementioned application, a locking device is proposed comprising a housing, a first hook mounted cantilevered on a tilting axis carried by the housing to switch between an open position and a closed position by which the first hook supports a hooking member, and a retractable locking member arranged to oppose a rocking movement of the first hook by pressing a locking part of the first hook on the locking member, the device further comprising a second hook adjacent to the first hook and a connecting member between the first hook and the second hook so that in the closed position of the first hook the second hook is held in a position close to a position in which the second hook supports the 'hooking member.

 Thus, in the event of failure of the first hook, the second hook is immediately put into service and takes over from the first hook to support the hooking member.

 According to a variant which is the subject of the present application, the connecting member is a common support block of which the first hook and the second hook are integral, the second hook comprising a catching edge recessed with respect to a catching edge of the first hook and a support part set back relative to a support part of the first hook on the locking member. Preferably, the first hook and the second hook are made in one piece with the common support block.

Other characteristics and advantages of the invention will appear on reading the following description of two particular non-limiting embodiments of the invention in conjunction with the attached figures, among which
- Figure 1 is an elevational view, partially in section, of a first embodiment of the locking device according to the invention, subject of application 91 11812;
- Figure 2 is a sectional view along the line
II-II of Figure 1,
- Figure 3 is a schematic illustration of a second embodiment of the invention, subject of application 91 11812
- Figure 4 is a side view of the locking hooks according to the variant of the present application
- Figure 5 is a side view in a direction opposite to Figure 4
- Figure 6 is a sectional view along the line
VI-VI of figure 4.

 Referring to Figures 1 and 2, in the first embodiment, the locking device according to the invention comprises a housing 1, a first hook 2 mounted on a pivot pin 3 carried by spacers 4 integral with the housing, and a second hook 5 mounted adjacent to the first hook 2 for tilting about a tilting axis 6 carried by spacers 7 also secured to the housing.

 In this first embodiment, the first hook 2 and the second hook 5 have almost identical shapes and their outline therefore largely overlaps in FIG. 1 all the more since their tilting axes are coaxial.

 The first hook 2 and the second hook 5 are mounted cantilevered with respect to their respective pivot axis, that is to say that in the closed position, a hooking member 8 bearing on the hooks tends to tilt these to an open position in which the hooking member 8 escapes from the hooks.

The hooking member 8 is for example a hooking rod fixed to a thrust reverser flap 9 by gussets 10. To keep the first hook 2 in the closed position as illustrated in FIG. 1, the locking comprises a locking member generally designated at 11 inserted between a locking portion 12 of the hook 2 and a stop 13 carried by the housing.

 In the particular embodiment illustrated, the locking member 11 comprises a control rod 14 mounted to slide in a bore of the housing 1 and comprising a shoulder 15 on which bears a spring 16 which tends to bring the locking member towards an insertion position between the locking part 12 of the hook 2 and the stop 13. At its end facing the hook 2, the locking member 11 comprises a yoke 17 supporting a locking roller 18. The control rod 14 is connected to a lever 19 hingedly attached to the housing 1 and the housing 1 supports a hydraulic cylinder 20 whose rod 21 extends facing the lever 19. The control cylinder 20 is connected by a conduit 22 to a solenoid valve 23 connected to an electronic central control unit not represented by an electrical line 24. The first hook 2 is normally returned to an open position by a spring 25 having an extr moth-eaten attached to the hook 2 and an end fixed to the housing 1.

 The first hook 2 and the second hook 5 are associated by a connecting member comprising a helical spring 26 bearing on a tongue 27 secured to the first hook 2 and a tongue 28 secured to the second hook 5 to rotate the hook 2 and the hook 5 in opposite directions so that in the closed position a locking part 29 of the second hook 5 is normally set back from the locking part 12 of the first hook 2 relative to the locking member 11, which further comprises a roller 30 carried by the yoke 17 opposite the locking part 29 of the second hook 5.

Unlike the locking part 12 of the first hook 2 which is preferably rectilinear to allow the roller 18 to be released from the locking member 11, the locking part 29 has a concave curvilinear shape matching the shape of the roller 30 in order to cause mechanical locking of the locking member 11 when the locking part 29 is in contact with the latter. The spacing movement of the hook 5 relative to the hook 2 resulting from the action of the spring 26 is limited by the cooperation of a finger 31 carried by the first hook 2 with a slot 32 made in the second hook 5.

 A lever 33 is mounted on the housing 1 to pivot and has one of its ends in contact with a shoulder 34 of a gusset 10 supporting the hooking member 8, and an opposite end in contact with a position detector 35 connected to the control solenoid valve 23 by a line 36. A position detector 37 of the second hook 5 is also fixed to the housing 1 and extends opposite an edge of the hook 5 comprising a convex profile 38 adjacent to a profile concave 39.

 The operation of the device according to this embodiment of the invention is as follows: during normal operation, and for a closed position of the reversing flap of the thrust flap 9, the device is in the state shown on Figure 1 that is to say that the locking portion 12 of the first hook 2 is supported on the roller 18 of the locking member 11 and the hook 2 therefore supports the hooking member 8 to hold the flap 9 in the closed position. The second hook 5 is pushed back by the spring 26 in an anti-clockwise direction. This movement is limited by the first contact of the hook 5 with the hooking member 8 and in this position the locking part 29 of the hook 5 is slightly spaced from the locking roller 30 of the locking member 11.The stop finger 31 is arranged substantially in the middle of the slot 32. The second hook 5 is therefore in contact with the hooking member 8 but does not support the latter. The lever 33 for detecting the position of the latching member 8 bears on the rod of the detector 35 to indicate that the flap 9 is properly closed. The convex part 38 of the edge of the second hook 5 is opposite the position detector 37 and the latter therefore transmits a signal for correct positioning of the second hook 5. The control valve 23 is therefore not inhibited and the withdrawal of the 'locking member 11 can be controlled by line 24 to cause the opening of the locking device.

 If the first hook 2 or its tilting axis 3 breaks due to the load or vibrations to which it is subjected, the flap 9 tends to open and drives the hooking member 8. In this movement, the second hook 5 pivots anti-clockwise until its locking part 29 comes into contact with the roller 30 of the locking member 11 which is then mechanically blocked by the concave shape of the part of locking 29. In addition, the movement of the hooking member 8 causes the lever 33 to pivot and the detector 35 then sends a signal inhibiting the control valve 23 of the opening jack 20.

 If the second hook 5, or its tilting axis 6 breaks while the first hook 2 is in the closed position, the second hook 5 n1 is no longer supported on the hooking member 8 and the remaining part of the hook 5 tends to tilt clockwise under the effect of the spring 26. The concave portion 39 of the edge of the hook 5 then comes opposite the position detector 37 which sends a failure signal from the second hook 5 inhibiting the control valve 23.

 In the second embodiment shown schematically partially in Figure 3, the elements having a function similar to those of Figure 1 have been referenced with the same reference numerals.

 In this embodiment, the first hook 2 is always mounted in a cantilever, that is to say that its tilting axis 3 is offset with respect to the reaction direction of the hook (represented by an arrow), when 'it supports the hooking member 8. The hook 2 comprises, as before, a locking part 12 bearing on the locking roller 18 of the locking member 11.

 The second hook 5 is this time a self-locking hook, that is to say that the tilting axis 6 is arranged in a reaction direction of the hook when the latter supports the hooking member. The second hook further comprises a concave support surface 40 for receiving the hooking member 8. Furthermore, the second hook 5 is connected to the locking member 11 by a telescopic rod 41 having one end fixed to the second hook 5 and one end fixed to the locking member 11, and biased in a direction of extension by a spring 42. The offset between the first hook 2 and the second hook 5 is limited by a stop 43 carried by the first hook 2 and extending in a curvilinear slot 44 produced in the second hook 5: The relative position of the stop 43 and of the slot 44 is determined so that in the closed position illustrated in FIG. 3 and when the stop 43 is at the bottom of the slot 44, the concave support surface 40 of the second hook 5 is slightly set back relative to the hooking member 8.

 The operation of this second embodiment is as follows: in the normal position of use illustrated in FIG. 3, the hooking member 8 is supported by the first hook 2 If the latter or its tilting axis is broken l 'hooking member 8 comes to bear on the second hook 5 which supports it and simultaneously provides mechanical locking of the locking member 11. If the second hook 5 breaks, the spring 42 tends to pivot the remaining part of the hook 5 which is no longer retained by the positioning finger 43 and the detector 37 sends an inhibition signal from the control valve 23.

 If the two hooks are in good working condition, the operation of the control jack 20 causes the locking member 11 to be withdrawn, which in turn causes the second hook 5 to retract. After total removal of the locking member 11 and the hook 5 associated therewith, the first hook 2 switches in the usual way towards the open position under the effect of the hooking member 8 and the return spring 25.

 When closing the hook 2 is brought into the closed position before the engagement of the locking member 11 and the hook 5 is therefore kept apart until the hook 2 is not closed.

 Figures 4 to 6 illustrate an alternative embodiment of the device of Figure 1. To simplify the explanations, only the locking hooks have been shown as well as the rupture detector of the second hook.

 In this alternative embodiment, the first hook 2 and the second hook 5 are carried by a common support block 45 with which they are preferably made in one piece, for example by machining a metal block.

The common support block 45 is mounted to tilt about a tilting axis 3. As previously, the first hook 2 has a locking part 12 bearing on the locking roller 30 when the hook is loaded, that is to say say when a latching member 8 is supported on a latching edge 46 of the hook 2. In this position which is shown in the figures, the latching member 8 is immobilized and therefore retains the object to which it is associated.

 So that the second hook 5 is not loaded simultaneously with the first hook, the second hook has a hooking edge 47 which is set back from the hooking edge 46 of the first hook. The second hook further comprises a support part 29 on the locking roller 30 which is also set back relative to the support part 12 of the first hook. Furthermore, the rupture detector 37 of the second hook bears on the latter at any point on the edge of the second hook. Indeed, if the second hook breaks while it is not loaded, the break will take place in the narrowest part, that is to say at the connection with the common support block 45. The broken hook will fall and detector 37 will report this regardless of its position along the edge of the hook.

 If the first hook breaks, the hooking member 8 will bear on the edge 47 of the second hook and will rotate the latter until the bearing part 29 comes into contact with the roller 30. The device will then blocked in the locked position as in the case of FIG. 1.

 It will be noted that the offset between the edges 46 and 47 on the one hand and the parts 12 and 29 on the other hand, could be very small to keep the second hook unloaded as long as the first hook is in service. However, it is preferable to provide a sufficient offset so that the door position detector 35 is acted upon over a stroke long enough to detect a change of situation without using a very sensitive detector.

 Without departing from the scope of this alternative embodiment, it is also possible to attach the two hooks to the common support block 45 instead of making them in one piece with the latter.

Claims (2)

 1. Locking device comprising a housing (1), a first hook (2) mounted in cantilever on a tilting axis (3) carried by the housing to switch between an open position and a closed position in which the first hook (2) supports a hooking member (8), a retractable locking member (30) arranged to oppose a tilting movement of the first hook by pressing a locking part (12) of the first hook on the locking member, a second hook (5) adjacent to the first hook and a connecting member between the first hook (2) and the second hook (5) so that in the closed position of the first hook (2 ), the second hook (5) is held in a position close to a position in which the second hook supports the hooking member, characterized in that the connecting member is a common support block (45), the first hook (2) and the second hook (5) are integral, the second hook (5) having a catching edge (47) recessed with respect to a catching edge (46) of the first hook and a support part (29) recessed with respect to a support part (12 ) of the first hook on the locking member (30).  2. Locking device according to claim 1 characterized in that the first hook and the second hook are made in one piece with the common support block (45).