FR2794789A1 - DEVICE FOR LOCKING A COVERING ELEMENT ON A SUPPORT FRAME - Google Patents

Abstract

The device comprises a pivot comprising an engagement region and to which a latch is attached, and a removable key (3) comprising a lug engagement region (s) to cooperate with a ramp of said element or of the pivot, the regions of 'respective meshing being nestable when the lug (33) is slid in the ramp towards the latch, and cannot be dislocated after rotation of the key, except after rotation in the opposite direction. The key (3) also includes a lug (42) ) retractable requested by an elastic return member (44) adapted to, after rotation of the key by a predetermined angle, also be pushed into the ramp and prevent rotation of the key in the opposite direction, except retraction of the lug ( 42) against the effort of the return device (44). Use: securing the operation of buffers or road gates.

Description

The invention relates to devices for locking an element

  covering, for example of the buffer or grid type, on a support frame.

  It applies in particular to devices for closing inspection or inspection chimneys of an underground water network, such as manholes or sidewalks, to devices for closing technical inspection chambers of a network. underground cable, such as hatches, and to manhole crowning devices such as

road grids.

  Indeed, the inspection of water networks or cable networks l0 traversing the basement is made possible by the presence of manholes or hatches comprising a frame closed by a covering element,

  generally made of cast iron, placed flush with the ground surface.

  These covering elements are locked by a locking device comprising a pivot which extends along a pivot axis crossing the thickness of the covering element and which is fixed to this element so that it can pivot in that -this; this pivot comprises under the covering element an end region o is fixed a movable locking latch with it between a locking position o it is at least partly opposite a part of the frame or d '' a chin fixed to it, and a release position where it is facing a light of the

  frame so that the covering element can then be itself

  even pivoted or removed from the frame to clear the view, the locking and release positions of the latch are generally defined by stops. So that the pivot can be actuated in rotation so as to drive the latch for locking from the locking position to the release position or vice versa, it comprises, on the side of its outer end facing the eye, a meshing region suitable for fitting with an engagement region provided at one end of a removable key, when the engagement regions of the pivot and the key are in a predetermined relative position; thus, when these regions are nested and meshed, a rotation of the key around the pivot axis of the pivot causes a rotation

of the pivot.

  To facilitate the operation of the covering element, the locking device is generally designed so that the key has a head also serving as an operating handle on which one can exert traction to pivot or remove the covering element. To this end, the key has in its engagement region one or more pins extending radially outward relative to the pivot axis of the pivot which is also that of the key, and the covering element has , above the pivot engagement region, a bulkhead having a lumen whose outline is similar to that of the cross section of the key when the engagement region thereof is opposite the region of engagement of the pivot in the locked position and in the relative position allowing the nesting, but of dimensions

slightly higher.

  Thus, when the pivot is in the locked position and the engagement regions of the key and the pivot are opposite in their relative nesting position, the key can be introduced into the lumen of the element covering and sliding along a section of entry ramp formed by the wall of the light and extending approximately in the same direction as the pivot axis of the pivot then fitted with the pivot, and therefore a rotation of the key intended to rotate the pivot slides the lug of the key along a section of retaining ramp extending in a plane approximately perpendicular to the axis, formed by the underside of the lips of the partition the cover member overhanging the engagement region of the pivot; thus, when, as a result of this movement of the "bayonet mount" type, the key has been turned enough so that the pivot is in the release position, any traction exerted on the key is transmitted to the rail of the element lips cover, and it can then be lifted from the frame for example by

  pivoting if it is pivotally mounted on the frame.

  The key can then either be removed provided that it is rotated in the opposite direction to the previous one causing the lug to slide along the retaining ramp, followed by a translation causing a slide along the entry ramp, or be left in interlocking relationship with the pivot. By way of example, it is possible to provide embodiments in which the engagement region of the pivot is formed at one end of the latter by a pivot head extending in the longitudinal direction thereof and having a prismatic shape with a polygonal cross section, and the region of engagement of the key is a chamber of complementary shape (a simple example being a pivot having a "square" male and a key having a "square" female), and o the lug extending radially outward is carried by the lateral surface of the region

of key engagement.

  In another simple embodiment, the engagement region of the pivot is formed at one end thereof by a pivot head having at the end a slot similar to a screw head slot, and the engagement region of the key is an end bar extending radially on either side of the pivot axis and adapted to fit into the slot of the screw after having passed through an oblong opening in the upper partition of the element recovery; in this case, the regions of the strip projecting on either side of the axial body of the key themselves play the role of lugs, since after rotation of the key, these two regions of the strip extend under the lips of the partition bordering the oblong lumen laterally and thus allow the element to be raised

of recovery.

  One drawback of these locking devices, which the invention aims to remedy, lies in the fact that an involuntary rotation of the key during the pulling exerted on it to lift the covering element risks bringing the lug or the pins near the entry section of the corresponding ramp, and thus the disengagement of the key and the pivot and the tilting of the covering element either towards the frame or towards

  outside of it, risking injury to the operator.

  Another drawback which the invention aims to remedy is that the key being held loosely, a slight force exerted on it can cause, for example when the cover element is open, its

  rotation, its accidental fall and even its loss, unnoticed.

  In this case, the disengagement takes place while the pivot is in the locked position, and if it is then possible to fold the element

  covering against the frame, it is impossible to lock it.

  Another disadvantage is that, in order to be able to fit the key and the pivot, it is necessary that these are in a correct relative position, obtained only when the pivot is in the fully locked position (preferably defined by a stop) , but it suffices with a slight fortuitous pivoting of the pivot to note, after insertion of the key in the light, that the position of the pivot does not correspond to the position

  allowing nesting, and that it has become impossible.

  Yet another drawback is that the existence of the partition having a light, the periphery of which plays the role of a ramp for the lug of the key makes it necessary to create in the thickness of the covering element a chamber which must be produced during molding of the covering element by coring which complicates the molding operation and increases the

duration and cost.

  In addition, this chamber, which constitutes a trap for gravel and other road surface materials, the presence of which makes it difficult or

  impossible to insert the key, is difficult to clean.

  The object of the invention is to remedy these drawbacks as much as possible and mainly to avoid that the key can be unintentionally disengaged from the pivot. Preferred embodiments are intended

  to remedy the other disadvantages mentioned.

  To this end, the invention relates to a device for locking a covering element on a support frame, comprising a pivot which extends along a pivot axis passing through the thickness of the covering element and comprises on one side of the covering element an end region o is fixed a latch and on the other a mesh end region, and a removable key comprising a mesh end region having at least an engaging lug adapted to cooperate with a respective ramp of the covering element or of the pivot comprising an inlet section extending approximately in the same direction as the pivot axis and a retaining section extending in a plane approximately perpendicular to this axis, the regions of engagement of the pivot and of the key being adapted to fit together when the lug is slid towards the fixing end of the latch along the entry section e and the dislocation being made impossible when then by rotation of the key around the pivot axis the lug has been slid along the retaining section unless the key is given a prior rotation in the opposite direction, characterized in that the key engagement region also has at least one retractable engagement pin urged by an elastic return member towards the free end of the key engagement region to engage, after nesting of the engagement regions and rotation of a predetermined angle of the key, in the entry section and thus preventing rotation of the key in said opposite direction, that is to say in the direction allowing disengagement, less of

  retract the retractable lug against the force of the return member.

  Thanks to the fact that the dislocation of the key requires an action which is exerted voluntarily against the force of a return member of a lug, the risks of accidental dislocation of the key are eliminated and thus the risks of injuries to manpower inspecting manholes are avoided. The invention may also have one or more of the following characteristics: - to cooperate with a light provided in a partition of a covering element, this light having at least one notch, at least part of which constitutes an inlet section of ramp and being bordered by lips of which at least one lower face region constitutes a ramp retaining section, the key comprises an elongated body extending along a pivot axis and comprising, near a free end o the meshing region is arranged, at least one fixed meshing lug extending radially with respect to the axis towards the outside, and at least one retractable meshing lug also extending radially with respect to the 'axis outward; the ramp retaining section belongs to a groove hollowed out circumferentially in the covering element around the pivot axis, and limited by an abutment face for the fixed lug of the key; - The engagement region of the pivot and the engagement region of the key have polygonal cross sections of approximately similar shapes adapted to be put into interlocking relation; - The key engagement region has a generally prismatic shape extending along the pivot axis of the key, the cross section of which has a polygonal shape; - the key engagement region has a generally prismatic chamber extending along the pivot axis of the key and having a polygonal cross section, adapted to fit around a head of the pivot of similar shape; - to cooperate with a pivot head having at least one notch, at least one wall of which constitutes a ramp entry section, and at least one lip of which at least one lower face region constitutes a ramp retaining section, the key comprises an elongated body extending along a pivot axis and comprising, near a free end where the engagement region is arranged, at least one fixed engagement lug extending radially with respect to the inward axis, and at least one retractable engaging pin also extending radially with respect to the axis inward; the pivot comprises a generally cylindrical head with a circular cross section having in its lateral surface at least one groove opening at a free end of the head by a notch, at least one wall of which constitutes a section of entry guide ramp, this groove being hollowed out under a lip of the pivot, the lower face of which constitutes a section of retaining guide ramp; - The pivot head has a stop face for the fixed lug of the key; - The key engagement region has a generally cylindrical chamber extending along the pivot axis of the key, adapted to fit around a pivot head of similar shape, and in which extend at least one fixed lug and at least one lug

o retractable;

  the key comprises a body comprising a meshing region having a chamber adapted to fit around a head of the pivot and having two diametrically opposite openings making the chamber communicate with the outside and extending in a longitudinal diametrical plane of the body, and a retractable element partially housed in these lights and carrying at least one lug; - the retractable element is a pivoting lever; - the pivoting lever comprises an operating finger projecting outside the body, and one face of this lever is biased by a spring resting on it, constituting the elastic return member of the retractable lug - the element retractable is a slide; - The key comprises a pulling device comprising a screw whose head is housed in a notch of the slide, an operating ring in which is screwed the free end of the threaded body of the screw, and a helical spring surrounding a part of the body of the screw and constituting the elastic return member of the retractable lug;

  - The key has a head formed in the form of a handle.

  Other characteristics and advantages of the invention will emerge

  of the following description of embodiments of the invention

  given by way of nonlimiting examples, illustrated by the accompanying drawings in which: - Figure 1 is a schematic top view showing part of a covering element and a pivot for fixing a latch belonging to a locking device according to a first embodiment of the invention, - Figure 2 is a schematic front view with partial section, of a key belonging to a locking device according to the first embodiment of the invention, - Figure 3 is a schematic exterior profile view of the base of the key of Figure 2, - Figure 4 is a schematic front view also in partial section, of part of a variant key belonging to a device of locking according to the first embodiment, - Figure 5 is a schematic external profile view of the key part of Figure 4, - Figure 6 is a schematic perspective view of a part of a pivot of fi fixing a latch belonging to a locking device according to a second embodiment of the invention, - Figure 7 is a schematic front view with partial section, of a part of a key belonging to a locking device according to the second embodiment of the invention, - Figure 8 is an external schematic profile view of the base of the key part of Figure 7, - Figure 9 is a schematic front view also in partial section, of a part of a variant key belonging to a locking device according to the second embodiment of the invention, - Figure 10 is an external schematic profile view of the key part of Figure 9, and - Figure 11 is a schematic sectional view of a portion of a cover member in the closed position on a frame and of a locking device according to the second embodiment of the invention. The frame covering element 1 shown in FIG. 1 is a pad fitted with a pivot 2 belonging to a locking device according to a first embodiment of the invention. Pivot 2, which crosses part of the thickness of the pad, extends along a pivot axis perpendicular thereto (in the drawing, perpendicular to the plane of the sheet). For fixing the pivot to the buffer, the latter comprises in its lower region (when it is in the closed position of the frame) not visible in FIG. 1, a part of a partition pierced with a hole through which the pivot is pinched between two fastening or clamping elements, for example two nuts, carried by the latter; at one end of pivot 2 which is projecting

  below the partition is fixed a locking latch. Protruding

  above this partition, the pivot comprises a base 20 separated from the partition by a seal forming a brake on the accidental rotation of the pivot (also not visible); the pivot is extended above the base by a prismatic head 21 extending along the pivot axis, having a polygonal cross section. Also above the partition for fixing the pivot, and at a distance therefrom, the buffer 1 comprises, extending in parallel, another partition 10, the role of which will be explained below, pierced with a light 11 more larger dimensions than those of the cross section of the prismatic head, intended to allow

  the passage of a pivot actuation key.

  The key 3 shown in FIGS. 2 and 3 and that in FIGS. 4 and are intended to actuate the pivot 2 of FIG. 1 in rotation. To this end, they comprise at one end a head 30, and starting from this head 30, an elongated body 31 extending along a pivot axis intended during

  actuation of the pivot to merge with the pivot axis thereof.

  At the free end of the body 31, opposite the head 30, opens a chamber 32 of prismatic shape extending along the pivot axis, having a polygonal cross section having the same shape as that of the head 21 of the pivot 2 but of very slightly larger dimensions, so that the chamber 32 can come into interlocking relation with the head 21 and that, thanks to their polygonal shape (here pentagonal), these two end regions of the key 3 and of the pivot 2 mesh with each other so that a rotation of the key around the pivot axis causes a

  rotation of the pivot and thus of the latch around this axis.

  However, the head 30 of the keys of FIGS. 2 to 5 being intended to be used as a handle for lifting the pad when the key and the pivot are engaged and engaged in the release or unlocking position of the latch, it is necessary that in this position the key does not have the

  possibility of dislodging under the action of a simple pull exerted on it.

  To this end, the lateral partition of the engagement chamber of the body of the keys of FIGS. 2 to 5 comprises, in the immediate vicinity of its free end, two lugs 33 extending radially outward and diametrically opposite, and the light 11 of the upper partition 10 of the buffer has a shape similar to the outer shape of the cross section of the engagement end region of the key including these two pins but of slightly larger dimensions, in the position occupied by the key when this and the pivot are fitted in the latch locking position. Thus, the wall of two notches 12 of the lumen intended for the passage of the lugs 33 constitutes a section of guide ramp 13 for the lugs when the latter enter the buffer or covering element, which inlet section 13 extends in the same direction as the pivot axis; naturally, the dimensions of the light 11 are chosen large enough so that once the lugs 33 are no longer engaged in the notches 12 following their sliding towards the latch, the key can be turned in the light 11 to bring the pivot and the latch in the release position; the underside of the lips 14 of the partition overhanging the region of engagement of the pivot and extending in a plane perpendicular to the pivot axis also constitutes a section of ramp 15, retaining the pins and thus the key, the region of which d 'meshing is therefore kept meshed and fitted with that of the pivot, when the latter has been turned following its sliding in the inlet section 13; it is advantageous to provide that the partition 10 has a sufficient thickness so that the regions of its lower face forming ramps are set back up, that is to say belong to grooves hollowed out circumferentially around the pivot axis in this upper partition, so that the retaining sections 15 extend over an arc of circumference limited by an end face forming a stop 16 for the corresponding lug 33 when the key is

  in the release position of the latch.

  Furthermore, according to the invention, while the disengagement of the keys 3 of FIGS. 2 to 5 and of the pivot 2 is made impossible when the lugs 33 are meshed under the upper partition 10 of the pad after rotation of the key from its position of introduction into the lumen and thus sliding of the lugs along the retaining section 15 of the ramp, unless the key is rotated in the opposite direction beforehand, the region of engagement of the key has one or more lugs additional gear

  retractable to prevent such rotation in the opposite direction.

  Thus, the key illustrated in Figures 2 and 3 has a retractable lug and that illustrated in Figures 4 and 5 has two lugs

retractable.

  More specifically, the lateral partition of the chamber 32 for meshing the key has two diametrically opposite openings 34 making the chamber communicate with the outside and extending in a longitudinal diametrical plane of the body 31 of the key, the partition comprising on either side of one of the openings, respectively, two protrusions 35 projecting outwards, arranged facing each other, in which are housed the ends of a pin 40 extending orthogonally to the pivot axis of the key. Around the spindle 40, is pivotally mounted a lever 41 movable between a position (in solid lines in Figure 2) in which it bears against the wall of the lights 34 which is closest to the free end of the body of the key and which extends in a plane perpendicular to the axis of pivoting of the key and a position (partly sketched in broken lines) in which it is raised near the opposite wall of the lights. This lever 41, which passes through the body 31, comprises, opposite the pin 40 around which it is pivotally mounted, a protruding part outside the body of the key, comprising on the one hand a lug 42, projecting towards the bottom along the side wall of the body 31 and extending to near the plane of the free end thereof when the lever is in abutment against the lower wall of the lights, and on the other hand a finger of maneuver 43 which then projects widely outwards and slightly upwards. The lever 41 is subjected to a return force towards its position of support against the wall of the lights 34 which is closest to the free end of the body, by an elastic return member 44 such as a steel wire with spring of which one end is wound around the pin 40 for pivoting the lever, the central part is wound around another pin 45 parallel to the first and disposed in the upper part of the chamber 32, and the opposite end is in pressure against the upper face of the lever 41 (the furthest from the lower wall of the openings 34). Thus, the lug 42 is normally, under the action of the spring 44, in the immediate vicinity of the free end of the region of engagement of the key, but is retractable against the force of the organ return, for example by pressing upwards, or by raising its operating finger 43, in the direction of the head 30. If the lock is a quarter-turn lock, the two planes passing through the pivot axis of the key and respectively the direction in which extend the fixed engaging lugs 33 and the direction in which the pivoting lever 41 extends, intersect at right angles; generally, the angle is equal to that between the locking direction and the release direction, the retractable lug 42 being intended to engage in a notch 12 of the lumen 11 of the upper partition 10 of the pad

  when the pivot 2 is in the latch release position.

  Indeed, when the pivot 2 is in the fully locked position (in abutment), as we have seen, it is possible simultaneously to fit the key 3 around it and to slide the fixed lugs 33 thereof in the notches 12, while the retractable lug 42 rises as a result of the presence of the

  upper partition 10 of the buffer; then, when, the fixed pins 33 being

  beyond the notches, the key can be turned to the release position of the latch, the retractable lug 42 slides over the partition until the release position is reached, the key and the pivot being always fitted and engaged; then, the retractable lug 42 is in turn facing the notch 12, and under the return force of the spring 44, it is pushed along the section

entry 13 of the ramp.

  It follows that in this release position, any rotation of the key and the pivot in the opposite direction is prevented, unless retracting the lug 42 by acting on the operating finger 43 against the force of the recall member 44. Thus, it is possible to use the head 30 of the key

  as a handle for lifting the cover or cover element 1.

  To remove the key, it is first necessary to retract the retractable engaging lug 42, then turn the key to the latch locking position by sliding the fixed lugs 33 in the retaining section 14 of the ramp, and finally to pull the key to slide the fixed lugs 33 in the inlet section 13, which can hardly be done by chance, and therefore significantly limits the risk of the pad falling back. The lateral partition of the chamber 32 for engaging the key in FIGS. 4 and 5 also has two diametrically opposite openings 34 making the chamber communicate with the outside and extending in a longitudinal diametral plane of the body 31 of the key. These two openings constitute guide rails in which are inserted lateral wings 51 of a slide 50 passing right through the body 31 of the key and including parts of the wings 51 which are prominent outside the body of

  the key constitutes the retractable pins 52.

  The retraction device for the slide 50 and thus the lugs 52 is a pulling device comprising a screw 53 extending axially in the body of the key, the head of which is housed in a notch 54 of the slide opening into the side of the slide which is close to the free end of the body of the key and clearing the chamber 32 for engaging the key sufficiently so that the fitting of the key on the pivot is not hampered by the presence of the slide; the threaded body of the screw 53 opens out between the branches of the head 30 forming a handle and its free end is screwed into a tapped hole extending radially in

an operating ring 55.

  To allow retraction of the slide 50 to the bottom of the lights 34 or near the bottom, and the passage of the screw 53, the body 31 of the key has a bore 36 extending the engagement chamber

  32 to the vicinity of the end of the body connected to the head 30 of the key.

  The diameter of this bore 36 is large enough to accommodate an elastic return member 56 such as a helical spring with non-contiguous turns wound around a part of the length of the body of the screw 53, the length of which is chosen such that so that when the free end of the slide 50 is approximately flush with that of the body of the key and when the operating ring 55 is in abutment against the opposite end of the body, it is itself in abutment without being compressed at one end against the slide and at

  the opposite end against the bottom of the bore 36.

  As in the previous embodiment, if the lock is a quarter-turn lock, the plane in which the lights extend and here the slide, and the diametrical plane of the body in which the pins extend

  fixed 33, intersect at right angles.

  When the pivot 2 is in the fully locked position (in abutment), it is possible simultaneously to fit the key 3 around it and to slide its fixed lugs 33 in the notches 12, while the slide rises as a result of the presence of the upper partition 10 of the buffer; then, when the fixed lugs 33 being beyond the notches, the key can be turned towards the latch release position, the retractable lugs 52 slide on the partition until the release position is reached, the key and the pivot being always fitted and engaged; then, the retractable lugs 52 are in turn facing the notches 12, and under the return force of the spring 56, they are pushed along the inlet section 13 of the ramp. It follows that in this release position, any rotation of the key and the pivot in the opposite direction is prevented, unless retracting the pins 52 by acting on the operating ring 55, against the force of the return member 56. Thus, it is possible to use the head 30 of the key as a handle for safely lifting the buffer 1. To disengage the key, it is first necessary to retract the retractable engaging lugs 52, then to turn the key to the latch locking position by sliding the fixed lugs 33 in the retaining section 14 of the ramp, and finally pull the key to slide the fixed lugs 33 in the

entrance section 13.

  While the embodiments of Figures 1 to 5 require for their use that the key is in a predetermined position relative to the lumen of the pad (first "indexing") and further that it is simultaneously in a predetermined position by relative to the head of the pivot (second "indexing"), which is not achieved if the pivot has been accidentally turned, a case which requires the pivot to be returned to the correct position by makeshift means, the embodiments of

  Figures 6 to 11 are single indexing devices.

  In these embodiments as in the previous ones, the pivot 2, which passes through at least part of the thickness of the pad 1 (FIG. 11), extends along a pivot axis perpendicular thereto; for fixing the pivot to the buffer, the latter comprises in its lower region (when it is in the closed position of the gaze), a partition part pierced with a hole through which the pivot passes, placed between two fixing elements, here constituted above the partition by the base 20 of the pivot separated from the partition by a seal forming a brake against the accidental unlocking of the pivot

  and below by pivot legs folded back against the latch itself

  even adjacent to the partition; the pivot is extended above the base by a head 21 extending along the pivot axis. On the other hand, unlike the previous embodiments, it is not necessary for the pad to have another partition above the fixing partition because the ramps are produced in the head 21 of the pivot (FIG. 6) in order to cooperate also with meshing lugs which the lateral partition of the meshing chamber of a key comprises, but extending this time

  - radially inward of the chamber.

  More specifically, the head 21 of the pivot 2 here has a generally cylindrical shape with a circular cross section and comprises in its lateral surface at least one groove, here two diametrically opposite grooves, intended for the passage of the pins. Each groove opens at the free end of the head 21 by a notch 22 whose wall constitutes a section of inlet guide ramp 23 extending in the same direction as the pivot axis, and is hollowed out under a lip 24 of the pivot, the underside of which constitutes a section of retaining guide ramp 25 extending in a plane perpendicular to the pivot axis and circumferentially around this axis, along an arc here of a value close to 90, but possibly possibly higher or lower; The end of the arc of circumference on which the groove extends is materialized by a face forming a stop 26

for the lug on the key.

  The key 3 illustrated in FIGS. 7 and 8 and that of FIGS. 9 and 10 are intended to actuate the pivot 2 of FIGS. 6 and 11 in rotation. To this end, they comprise at one end a head 30 and starting from this head 30 an elongated body 31 extending along a pivot axis intended during

  actuation of the pivot to merge with the pivot axis thereof

  this. At the free end of the body 31 opposite the head 30, there opens a chamber 32 here of generally cylindrical shape extending along the pivot axis, of dimensions slightly greater than those of the head 21 of the pivot 2 of such so that room 32 can come into relation

fitting with the head 21.

  The lateral partition of the key engagement chamber of FIGS. 7 to 11 comprises, flush with its free end, two pins 33 extending radially inside and in the direction of the longitudinal axis of the

chamber, diametrically opposite.

  It follows from this structure that, unlike the case of the embodiments of FIGS. 1 to 5, whatever the position of the pivot, from its locking position in abutment to its release position in abutment, it is possible to fit the chamber 32 for engaging the key and the head 21 for engaging the pivot, simply by sliding the lugs 33 into the notches 22. In addition, this time, the rotation of the key causing the lugs 33 to slide in the groove, causes no rotation of the pivot until the lugs 33 have not reached the abutment face 26 as a result of the

  shapes given to the chamber and the head.

  Analogously to the embodiments of FIGS. 1 to 5, according to the invention, on the one hand the disengagement of the keys 3 of FIGS. 7 to 10 and of the pivot 2 of FIG. 6 is made impossible when the lugs 33 are meshed under the upper lip this time of the pivot after rotation of the key, unless the latter is rotated beforehand in the opposite direction, and l0 on the other hand the region of engagement of the key has one or more retractable lugs d gear intended to prevent such rotation in

reverse.

  Thus, the key illustrated in FIGS. 7 and 8 includes, like that in FIGS. 2 and 3, a retractable lug, and that illustrated in FIGS. 9 and 10

  comprises two retractable lugs like that of FIGS. 4 and 5.

  The key of Figures 7 and 8 having very many points in common with that of Figures 2 and 3, only will be described in detail below its characteristics which differ from the corresponding characteristics of the key of Figures 2 and 3; the corresponding elements are designated in the

  drawings and description by the same reference numerals. Outside

  from the fact that has already been mentioned, that in the embodiment of FIGS. 7 and 8, the fixed engaging lugs 33 are interior and not exterior, and that the chamber 32 is apart from that of generally cylindrical and non-polygonal shape, the essential difference relates to the pivoting lever 41 and its environment. Indeed, as here the lug 42 is intended to mesh in a notch 22 of the pivot 2, this lug must also protrude inside the chamber 32. It follows that that of the lights 34 which does not extend not between the projections 35 o are housed the ends of the spindle

  , opens at the free end of the body 31 to allow passage to the lever 41.

  Thus, the lever 41 is movable between a position in which it is in abutment against a wall of the lumen 34 which extends between the projections 35 and a position in which it is raised near the opposite wall of the lumens 34; depending on the position of the lever 41, a more or less large part of the lug 42, which projects downwards, extends between the side walls of the lumen which opens at the free end of the body 31; when the lever bears against the lower wall of the other lumen, this lug 42 is approximately as prominent in the chamber 32 as is the lug

  fixed 33, and it is flush with the free end of the body 31.

  Thus, when the chamber 32 is facing the head 21 of the pivot and the fixed lugs 33 facing the notches 22, it is possible simultaneously to fit the key around the pivot and to slide its fixed lugs in the notches, while the retractable lug 42 rises; then, when the fixed lugs 33 have reached the groove of the head 21, the key can be turned, the fixed lugs sliding along the sections of the retaining ramp and the retractable lug 42 sliding on the pivot, the latter then remaining motionless; when the retractable lug 42 is in turn facing a notch 22, under the return force of the spring 44, it is pushed along the

entry section 23 of the ramp.

  It follows that in this position any rotation of the key independently of the pivot is prevented, unless retracting the lug 42 by acting on the operating finger 43; the continuation of the movement of the key in the same direction, as a result of the pushing of the fixed lugs 33 on the abutment face 26 causes the pivot towards the release position of the latch, the key and the pivot being always fitted and engaged; then, it is possible to use the head 30 of the key as a handle for lifting the pad 1. To remove the key, it is first necessary to retract the retractable engaging lug 42, then to turn the key until the fixed lugs 33 reach the base of the notches 22, and pull the key to slide the

  fixed pins 33 along the inlet section 23.

  Similarly, the key of Figures 9 and 10 having many points in common with that of Figures 4 and 5, only will be described in detail below its characteristics which differ from the corresponding characteristics of the key of Figures 4 and 5; the corresponding elements

  are designated in the drawings and the description by the same references

  digital. Apart from the fact which has already been mentioned, that in the embodiment of FIGS. 9 and 10, the fixed engaging lugs 33 are interior and not exterior, and that the chamber 32 is apart from that of generally cylindrical shape and not polygonal, the essential difference relates to the slide 50. Here, simply, the lateral wings 51 of this slide 50 do not have any protruding parts outside the body of the key but, on the other hand, prominent parts in the chamber 32 which constitute the

retractable lugs 52.

  In this way, when the fixed lugs 33 are facing the notches 22 of the pivot, it is possible simultaneously to fit the key 3 around the pivot and to slide its fixed lugs 33 in the notches 22,

  while the slide goes up; then, when, the fixed pins 33 being

  beyond the notches, the key can be turned, the retractable lugs 52 slide on the pivot until they are themselves facing the notches, and under the return force of the spring 56, they are pushed along of the entry section 23 of the ramp. It follows that in this position any rotation of the key relative to the pivot is prevented, unless retracting the lugs 52 by acting on the operating ring 55 against the force of the return member 56 Thus, it is possible to use the head 30 of the key as a handle for safely lifting the pad 1 or more generally the covering element. To disengage the key, it is first necessary to retract the retractable engaging lugs 52, then to turn the key until the fixed lugs reach the notches 22 by sliding them in the retaining section 25, and finally to pull the key

  for sliding the fixed pins along the inlet section 23.

  It will be noted that with these embodiments, the key can be put into interlocking and meshing relation with the pivot whatever the position thereof, and also separate regardless of its position thanks

  that there is only one indexing.

  FIG. 11 illustrates a locking device comprising a pivot 2 according to FIG. 6 and a latch 6 in the locking position under a stop 70 of the frame 7, as well as a removable key such as that of FIGS. 9 and

  , the pivot and the key being fitted.

  Of course, the invention is not limited to the embodiments described above and shown, and one can provide others without departing from its scope, in particular embodiments in which the pivot head, the meshing, the grooves and the lugs have particular geometric shapes so that a given covering element can only be opened by a single predetermined type of key.

Claims (16)

  1. Device for locking a covering element (1) on a support frame (7), comprising a pivot (2) which extends along a pivot axis passing through the thickness of the covering element and comprises on one side of the covering element an end region o is fixed a latch (6) and on the other a meshing end region, and a removable key (3) comprising a region d the engagement end having at least one engagement lug (33) adapted to cooperate with a respective ramp of the covering element or of the pivot comprising an inlet section l0 (13; 23) extending approximately in the same direction as the pivot axis and a retaining section (15; 25) extending in a plane approximately perpendicular to this axis, the engagement regions of the pivot and of the key being adapted to fit together when the lug (33) is slid towards the latch fixing end along the tr entry lesson and dislocation being made impossible when then by rotation of the key around the pivot axis the lug has been slid along the retaining section unless printing on the key (3) a rotation beforehand in the opposite direction, characterized in that the engagement region of the key (3) also has at least one retractable lug (42; 52) of engagement engaged by an elastic return member (44; 56) towards the free end of the engagement region of the key in order to engage, after engagement of the engagement regions and rotation of an angle predetermined key, in the input section (13; 23), and thus prevent rotation of the key in said opposite direction, that is to say in the direction allowing disengagement, unless retracting the lug retractable against the effort of the return member. 2. Device according to claim 1, characterized in that, to cooperate with a light (11) provided in a partition (10) of a covering element (1), this light having at least one notch (12) including at at least one part constitutes a ramp entry section (13) and being bordered by lips (14) of which at least one lower face region constitutes a ramp retaining section (15), the key (3) comprises a body (31) elongated extending along a pivot axis and comprising, near a free end where the engagement region is arranged, at least one fixed lug (33) extending radially by relative to the axis outward, and at least one retractable lug (42; 52) of meshing also extending radially relative to the axis outward.   3. Device according to any one of claims 1 and 2,   characterized in that the ramp retaining section (15) belongs to a groove hollowed out circumferentially in the covering element (1) around the pivot axis, and limited by a stop face (16) for the fixed pin (33) of the key.   4. Device according to any one of claims 1 to 3,   characterized in that the engagement region of the pivot (2) and the engagement region of the key (3) have polygonal cross sections of approximately similar shapes adapted to be put into interlocking relationships.   5. Device according to any one of claims 1 to 4,   characterized in that the key engagement region (3) has a generally prismatic shape extending along the pivot axis of the   key, the cross section of which has a polygonal shape.   6. Device according to any one of claims 1 to 5,   characterized in that the key engagement region (3) has a generally prismatic chamber (32) extending along the pivot axis of the key and having a polygonal cross section adapted   to fit around a head (21) of the pivot (2) of similar shape.   7. Device according to any one of claims 1 and 4 to 6,   characterized in that, in order to cooperate with a head (21) of the pivot (2) having at least one notch (22) of which at least one wall constitutes an entrance section (23) of ramp, and at least one lip (24 ) of which at least one lower face region constitutes a ramp retaining section (15), the key (3) comprises an elongated body (31) extending along a pivot axis and comprising, near a free end o is arranged the meshing region, at least one fixed pin (33) of meshing extending radially with respect to the axis inwards, and at least one retractable pin (42; 52) d also radially extending   relative to the axis inward.   8. Device according to any one of claims 1 and 4 to 7,   characterized in that the pivot (2) comprises a head (21) of generally cylindrical shape with a circular cross section having in its lateral surface at least one groove opening at a free end of the head by a notch (22) of which at least one wall constitutes a section of inlet guide ramp (23), this groove being hollowed out under a lip (24) of the pivot, the underside of which constitutes a section of retaining guide ramp (25).   9. Device according to any one of claims 6 to 8,   characterized in that the head (21) of the pivot has a stop face (26)   1 5 for the fixed lug (33) of the key.   10. Device according to any one of claims 1 and 4 to   9, characterized in that the key engagement region (3) has a generally cylindrical chamber (32) extending along the pivot axis of the key, adapted to fit around a head (21) of the pivot (2) of similar shape, and in which extend at least one fixed lug   (33) and at least one retractable lug (42; 52).   11. Device according to any one of claims 1 to 10,   characterized in that the key (3) comprises a body (31) comprising a meshing region having a chamber (32) adapted to fit around a head (21) of the pivot (2) and having two slots ( 34) diametrically opposite communicating the chamber with the outside and extending in a longitudinal diametral plane of the body, and a retractable element (41; 50) partially housed in these lights and carrying at least a lug (42, 52).   12. Device according to claim 11, characterized in that   the retractable element is a pivoting lever (41).   13. Device according to claim 12, characterized in that the pivoting lever (41) comprises an operating finger (43) projecting outside the body (31), and one face of this lever (41) is biased by a spring (44) resting on it, constituting the elastic return member of the retractable lug. 14. Device according to claim 11, characterized in that   the retractable element is a slide (50).   15. Device according to claim 14, characterized in that the key (3) comprises a pulling device comprising a screw (53) whose head l0 is housed in a notch (54) of the slide, an operating ring (55) in which is screwed the free end of the threaded body of the screw (53), and a helical spring (56) surrounding a part of the body of the screw and   constituting the elastic return member of the retractable lug.   16. Device according to any one of claims 1 to 15,   characterized in that the key (3) comprises a head (30) formed under the shape of a handle.