ZA200104482B

ZA200104482B - Device for locking a cover element on a support frame.

Info

Publication number: ZA200104482B
Application number: ZA200104482A
Authority: ZA
Inventors: Jean-Claude Hauer; Jean-Paul Pietrzak
Original assignee: Saint Gobain Pont A Mousson
Priority date: 1999-06-08
Filing date: 2001-05-31
Publication date: 2002-03-19
Also published as: FR2794789A1; BR0011351A; PT1183434E; AU5230100A; ATE265597T1; DE60010256D1; FR2794789B1; WO2000075465A1; ES2218170T3; EP1183434A1; DE60010256T2; AR024309A1; EP1183434B1; DK1183434T3

Description

,

Device for locking a covering element to a support frame

The invention relates to devices for locking a covering element for example of the plug or grille type to a support frame.

It applies in particular to devices for closing manholes or inspection shafts of an underground water network, such as shafts in the ground or pavement, devices for closing technical inspection chambers of an underground cable network, such as trap doors, and devices for capping manholes such as grilles in the roadway.

It is in fact possible to inspect water networks or cable networks which run underground as a result of the presence of manholes or trap doors comprising a frame which is closed by a covering element, generally made of cast iron, disposed at ground level.

These covering elements are locked by a locking device comprising a pivot pin which extends along a pivot axis passing through the thickness of the covering element, and which is fixed to this element such that it can pivot therein; this pivot pin has, below the covering element, an end region where a locking latch is fixed, which is movable with it between a locking position, in which it is at least partially opposite part of the frame or a dog fixed to the latter, and a freeing position in which it faces a hole in the frame such that the covering element can then itself be pivoted or withdrawn from the frame to open up the shaft, the locking and freeing positions of the latch being generally defined by stops.

So that the pivot pin can be actuated by rotation such that it carries the locking latch from the locking position to the freeing position or vice versa, it has on the side of its end outside the shaft an engagement region adapted to fit together with an engagement region provided at one end of a removable key when the engagement region of the pivot pin and that of the key are in a predetermined relative position; thus, when these regions are fitted together and engaged, rotating the key about the pivot axis of the pivot pin brings about rotation of the pivot pin.

To facilitate manoeuvring of the covering element, the locking device is generally designed such that the key has a head which also serves as a manoeuvring handle on which traction can be exerted to pivot or withdraw the covering element

To this end, the key has in its engagement region one or more pegs extending radially outwards with respect to the pivot axis of the pivot pin, which is also that of the key, and the covering element has, above the engagement region of the pivot pin, a partition having a hole whereof the contour resembles that of the cross-section of the key when the engagement region of the latter is opposite the engagement region of the pivot pin in the locking position and in the relative position allowing fitting together, but is slightly larger in its dimensions.

Thus, when the pivot pin is in the locking position and the engagement regions of the key and the pivot pin are opposite one another in their relative position of fitting together, the key may be introduced into the hole in the covering element and slid along an entry ramp section formed by the wall of the hole and extending approximately in the same direction as the pivot axis of the pivot pin and then fitted to the pivot pin, and from then on rotating the key with the intention of turning the pivot pin causes the peg of the key to slide along a retaining ramp section extending in a plane approximately perpendicular to the axis and formed by the lower face of the lips of the partition of the covering element overhanging the engagement region of the pivot pin; thus, as a result of this movement of the "bayonet mounting” type, when the key has been turned sufficiently for the pivot pin to be in the freeing position, any traction exerted on the key is transmitted to the ramp of the lips of the covering element, and the latter can then be lifted away from the frame for example by pivoting if it is mounted pivotally on the frame.” -

The key can then be withdrawn, provided that it is subjected to rotation in the opposite direction to the previous one, bringing about sliding of the peg along the retaining ramp, followed by a translational movement bringing about sliding along the entry ramp, that is to say it is left in the condition fitted to the pivot pin.

By way of example, it is possible to provide embodiments in which the engagement region of the pivot pin is formed at one end thereof by a head of the pivot pin

; extending in the longitudinal direction of the latter and hat shape of polygonal cross-section, and the engagement region of thrber of complementary shape (a simple example would be a pivo male square shape and a key having a female square shape), and in wextending radially outwards is borne by the lateral surface of the englo? of the key:

In another simple embodiment, the engagement region of 11S formed at one end thereof by a head of the pivot pin having at its endar t0 @ slotin@ screw head, and the engagement region of the key is an ending radially on either side of the pivot axis and adapted to fit into the sleeW after passing through an oblong hole in the upper partition of theslement, in this : case the regions of the bar projecting on either side of the : of the key themselves fulfil the role of pegs, since after the key has bei these two regions of the bar extend below the lips of the partition bordrally O" the oblong hole and thus allow the covering element to be lifted.

One disadvantage of these locking devices, which the inventthe object of overcoming, resides in the fact that unintentionally rotating tht the time of the traction exerted thereon in order to raise the covering elemerls a risk of bringing the peg or pegs close to the entry section of the coring ramp. and thus disengaging the key and the pivot pin from their fitting to and tilting the covering element either towards the frame or towards the outsereof, thus risking injury to the operator.

Another disadvantage which the invention has the object of owning iS that because the key is retained without great firmness a small foraerted thereon may, for example when the covering element is open, cause it otate, to accidentally fall and even to be lost without this being noticed. this case: the disengagement from fitting takes place when the pivot pin is ine locking postion. and although it is then possible to lower the covering element qo the frame itis impossible to lock it.

Another disadvantage consists in the fact that in order to enable the key and the pivot pin to be fitted together, it is necessary for them to be in the correct relative

Lo position, which is obtained only when the pivot pin is in the position of total locking (preferably defined by a stop), but a slight accidental pivoting of the pivot pin is all that is necessary to find, once the key has been introduced into the hole, that the position of the pivot pin does not correspond to the position allowing fitting together, and that the latter is now impossible.

Yet another disadvantage is that the existence of the partition having a hole whereof the periphery fulfils the role of a ramp for the peg of the key makes it necessary to make within the thickness of the covering element a chamber which must be formed at the time of moulding the covering element, by a core moulding which complicates the moulding operation and makes it longer and more expensive.

Moreover, this chamber, which forms a trap for gravel and other road-covering materials whereof the presence makes it awkward or impossible to introduce the key, is difficult to clean.

The object of the invention is to overcome as far as possible these disadvantages and mainly to prevent the possibility of the key being inadvertently disengaged from its fitting to the pivot pin. Preferred embodiments have the object of furthermore overcoming the other disadvantages mentioned.

To this end, the invention relates to a device for locking a covering element to a support frame, comprising a pivot pin which extends along a pivot axis passing through the thickness of the covering element, and has on cone side of the covering element an end region where a latch is fixed and on the other an end engagement region, and a removable key having an end engagement region having at least one engagement peg adapted to co-operate with a respective ramp of the covering element or of the pivot pin comprising an entry 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 engagement region of the pivot pin and that of the key being adapted to fit together when the peg is slid towards the fixing end of the latch along the entry section and disengagement from fitting together being made impossible when the key is subsequently rotated about the pivot axis and the peg has then been slid along the retaining section unless the key is made to perform a previous rotation in the opposite direction, characterised in that the engagement region of the key moreover has at least one retractable engagement peg which is urged by a resilient restoring member towards the free end of the engagement region of the key in order, after the engagement regions have been fitted together and the key has been rotated by a predetermined angle, to engage in the entry section and thus to prevent the key from rotating in the said opposite direction, that is to say in the direction allowing disengagement from fitting together, unless the retractable peg is retracted in opposition to the force of the restoring member.

Thanks to the fact that disengagement of the key from fitting requires an action exerted deliberately in opposition to the force of a restoring member of a peg, the risks of accidental disengagement of the key from fitting are eliminated and thus the risks of injury to the personnel in charge of inspecting the shafts are avoided.

The invention may also have one or more of the following features: - in order to co-operate with a hole provided in a partition of a covering element, this hole having at least one notch whereof at least a part forms an entry ramp section and being bordered by lips whereof at least a lower face region forms a retaining ramp section, the key comprises an elongate body extending along a pivot axis and having, close to a free end where the engagement region is disposed, at least one fixed engagement peg extending radially outwards with respect to the axis and at least one retractable engagement peg also extending radially outwards with respect to the axis; - the retaining ramp section is part of a groove hollowed circumferentially out of the covering element around the pivot axis and limited by a stop face for the fixed peg of the key; - the engagement region of the pivot pin and the engagement region of the key have polygonal cross-sections which are approximately similar in shape and adapted to be brought into the fitting-together condition;

- the engagement region of the key has a generally prismatic shape extending along the pivot axis of the key, whereof the cross-section has a polygonal shape; - the engagement region of the key has a chamber of generally prismatic shape which extends along the pivot axis of the key and has a polygonal cross-section, and which is adapted to be fitted around a head of the pivot pin of similar shape; - in order to co-operate with a head of the pivot pin having at least one notch whereof at least one wall forms an entry ramp section and at least one lip whereof at least one lower face region forms a retaining ramp section, the key comprises an elongate body extending along a pivot axis and having, close to a free end where the engagement region is disposed, at least one fixed engagement peg extending radially inwards with respect to the axis and at least one retractable engagement peg also extending radially inwards with respect to the axis; - the pivot pin has a head of generally cylindrical shape of circular cross-section having in its lateral surface at least one groove opening at a free end of the head in a notch whereof at least one wall forms an entry guide ramp section, this groove being hollowed out below a lip of the pivot pin whereof the lower face forms a retaining guide ramp section; - the head of the pivot pin has a stop face for the fixed peg of the key; - the engagement region of the key has a chamber of generally cylindrical shape which extends along the pivot axis of the key and is adapted to be fitted around a head of the pivot pin of similar shape, and in which at least one fixed peg and at least one retractable peg extend; - the key comprises a body having an engagement region having a chamber adapted to be fitted around a head of the pivot pin and having two diametrically opposed holes bringing the chamber into communication with the outside and extending in a longitudinal diametric plane of the body, and a retractable element housed partly in these holes and bearing at least one peg; - the retractable element is a pivotal lever;

- the pivotal lever has a manoeuvring finger projecting outside the body, and a face of this lever is urged by a spring bearing against it, forming the resilient restoring member of the retractable peg; - the retractable element is a slide; - the key has a drawing device comprising a screw whereof the head is housed in a hollow within the slide, a manoeuvring ring into which the free end of the threaded body of the screw is screwed, and a helical spring surrounding part of the body of the screw and forming the resilient restoring member of the retractable peg; - the key has a head formed in the shape of a handle.

Other features and advantages of the invention will emerge from the description which follows of embodiments of the invention which are given by way of non- restrictive example and are illustrated by the attached drawings, in which: - Figure 1 is a diagrammatic plan view showing part of a covering element and a pivot pin for fixing a latch which is part of a locking device according to a first embodiment of the invention, - Figure 2 is a diagrammatic front view in partial section of a key which is part of a locking device according to the first embodiment of the invention, - Figure 3 is an external diagrammatic side-face view of the base of the key in

Figure 2, - Figure 4 is a diagrammatic front view also in partial section of part of a variant on the key which is part of a locking device according to the first embodiment, - Figure 5 is an external diagrammatic side-face view of the part of the key shown in Figure 4,

- Figure 6 is a diagrammatic perspective view of part of a pivot pin for fixing a latch which is part of a locking device according to a second embodiment of the invention, - Figure 7 is a diagrammatic front view in partial section of part of a key which is part of a locking device according to the second embodiment of the invention, - Figure 8 is an external diagrammatic side-face view of the base of the part of the key shown in Figure 7, - Figure 9 is a diagrammatic front view also in partial section of part of a variant on the key which is part of a locking device according to the second embodiment of the invention, - Figure 10 is an external diagrammatic side-face view of the part of the key shown in Figure 9, and - Figure 11 is a diagrammatic sectional view of part of a covering element in the closed position on a frame and a locking device according to the second embodiment of the invention.

The frame covering element 1 shown in Figure 1 is a plug equipped with a pivot pin 2 which is part of a locking device according to a first embodiment of the invention.

The pivot pin 2, which passes through part of the thickness of the plug, extends along a pivot axis perpendicular thereto (in the drawing, perpendicular to the plane of the page). In order to fix the pivot pin to the plug, the latter has in its lower region (when it is in the closed position of the frame), which is not visible in Figure 1, a partition part through which there goes a hole which the pivot pin passes through, pinched between two fixing or clamping elements, for example two nuts, borne by the latter; at one end of the pivot pin 2 projecting below the partition a locking latch is fixed. Projecting above this partition the pivot pin has a base 20 separated from the partition by a sealing gasket forming a restraint on accidental rotation of the pivot pin (also not visible); the pivot pin is prolonged above the base by a head 21 of prismatic shape extending along the pivot axis and having a polygonal cross-section. Also above the partition for fixing the pivot pin and spaced therefrom, the plug 1 has extending parallel another partition 10 whereof the role will be explained below, through which there goes a hole 11 of larger dimensions than those of the cross- section of the prismatic head and intended to allow a key for actuating the pivot pin to pass through.

The key 3 shown in Figures 2 and 3 and that in Figures 4 and 5 are intended to actuate rotation of the pivot pin 2 in Figure 1. To this end, they have at one end a head 30 and, starting from this head 30, an elongate body 31 extending along a pivot axis which on actuation of the pivot pin is intended to become congruent with the pivot axis of the latter. At the free end of the body 31, opposite the head 30, a chamber 32 of prismatic shape opens up, extending along the pivot axis and having a polygonal cross-section of the same shape as that of the head 21 of the pivot pin 2 but of very slightly larger dimensions, such that the chamber 32 can engage in a fitting condition with the head 21 and such that, thanks to their polygonal (in this case, pentagonal) shape, these two end regions respectively of the key 3 and of the pivot pin 2 engage with one another so that rotating the key about the pivot axis brings about rotation of the pivot pin and thus of the latch about this axis.

However, because the head 30 of the keys in Figures 2 to 5 is intended to be used as a handle for lifting the plug when the key and the pivot pin are fitted together and engaged in the freeing or unlocking position of the latch, it is necessary for the key not to be able to disengage from this fitting in this position under the action of a simple traction exerted thereon.

To this end, the lateral partition of the engagement chamber of the body of the keys in Figures 2 to 5 has, in the immediate vicinity of its free end, two diametrically opposed pegs 33 extending radially outwards, and the hole 11 in the upper partition of the plug has a shape similar to the external shape of the cross-section of the end engagement region of the key including these two pegs, but of slightly larger dimensions, in the position which the key occupies when it and the pivot pin are fitted together in the locking position of the latch. Thus, the wall with two notches 12 of the hole, which are intended for the pegs 33 to pass through, forms a guide ramp section 13 for the pegs when the latter enter the plug or covering element, this entry section 13 extending in the same direction as the pivot axis; it goes without saying that the dimensions of the hole 11 are selected to be sufficiently large for the key, once the pegs 33 are no longer engaged in the notches 12 following their sliding towards the latch, to be able to be turned within the hole 11 to bring the pivot pin and the latch into the freeing position; the lower face of the lips 14 of the partition overhanging the engagement region of the pivot pin and extending in a plane perpendicular to the pivot axis also forms a ramp section 15, retaining the pegs and thus the key whereof the engagement region is thus kept engaged and fitted to that of the pivot pin when the key has been turned, following its sliding in the entry section 13; it is advantageous to provide for the partition 10 to have a thickness great enough for the regions of its lower face forming ramps to be upwardly recessed, that is to say to be part of grooves hollowed circumferentially around the pivot axis out of this upper partition, such that the retaining sections 15 extend over an arc whereof the circumference is limited by an end face forming a stop 16 for the corresponding peg 33 when the key is in the freeing position of the latch.

Moreover, according to the invention, while disengagement from fitting together of the keys 3 of Figures 2 to 5 and the pivot pin 2 is made impossible when the pegs 33 are engaged below the upper partition 10 of the plug after the key has been rotated from the position in which it is introduced into the hole and thus the pegs slid along the retaining ramp section 15, unless the key is made to perform a previous rotation in the opposite direction, the engagement region of the key has one or more additional retractable engagement pegs intended to prevent a rotation of this kind in the opposite direction.

Thus, the key illustrated in Figures 2 and 3 has a retractable peg and that illustrated in Figures 4 and 5 has two retractable pegs.

To be more precise, the lateral partition of the engagement chamber 32 of the key has two diametrically opposed holes 34 bringing the chamber into communication with the outside and extending in a diametric longitudinal plane of the body 31 of the key, the partition having on either side of one of the holes respectively two projections 35 protruding outwards and disposed facing one another, in which the ends of a pin 40 extending at a right angle to the pivot axis of the key are housed. A lever 41 is mounted to pivot about the pin 40, and this lever 41 is movable between a position (shown in solid lines in Figure 2) in which it bears against that wall of the holes 34 which is closest to the free end of the body of the key and extends in a plane perpendicular to the pivot axis of the key, and a position (sketched in partially in broken lines) in which it is raised into the vicinity of the opposing wall of the holes.

This lever 41, which passes through the body 31, has opposite the pin 40 about which it is pivotally mounted a part protruding outside the body of the key, comprising on the one hand a peg 42 projecting downwards along the lateral partition of the body 31 and extending into the vicinity of the plane of the free end thereof when the lever bears against the lower wall of the holes, and on the other hand a manoeuvring finger 43 which then projects outwards to a considerable extent and slightly upwards. The lever 41 is subject to a restoring force towards its position bearing against that wall of the holes 34 which is closest to the free end of the body, brought about by a resilient restoring member 44 such as a steel wire spring whereof one end is wound about the pin 40 for pivoting the lever, the central part is wound about another pin 45 parallel to the first and disposed in the upper part of the chamber 32, and the opposite end is pressed against the upper face of the lever 41 (that furthest away from the lower wall of the holes 34). Thus, under the action of the spring 44, the peg 42 is normally in the immediate vicinity of the free end of the engagement region of the key, but it is retractable in opposition to the force of the restoring member, for example by pressing upwards, or by lifting its manoeuvring 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, respectively the direction in which the fixed engagement pegs 33 extend and the direction in which the pivotal lever 41 extends, will intersect at a right angle; to speak in general terms, the angle is equal to that between the direction of locking and the direction of freeing, with the retractable peg 42 being intended to come into engagement in a notch 12 in the hole 11 of the upper partition 10 of the plug when the pivot pin 2 is in the freeing position of the latch.

Indeed, when the pivot pin 2 is in the position of complete locking (against the stop), as we have seen it is possible at the same time to fit the key 3 around it and to slide the fixed pegs 33 thereof in the notches 12, while the retractable peg 42 moves up again as a result of the presence of the upper partition 10 of the plug; then, once the fixed pegs 33 are beyond the notches, the key can be turned towards the freeing position of the latch, the retractable peg 42 slides on the partition until the freeing position is reached, the key and the pivot pin still being fitted together and engaged; at this point the retractable peg 42 in its turn faces the notch 12 and, under the force of the restoring spring 44, it is pushed along the entry section 13 of the ramp.

The result is that in this freeing position any rotation of the key and the pivot pin in the opposite direction is prevented unless the peg 42 is retracted by acting on the manoeuvring finger 43 in opposition to the force of the restoring member 44. Thus it is possible to use the head 30 of the key as a handle to raise the plug or covering element 1. To withdraw the key, first of all it is necessary to retract the retractable engagement peg 42 and then to turn the key to the locking position of the latch by sliding the fixed pegs 33 in the retaining section 14 of the ramp and then to draw the key in order to slide the fixed pegs 33 in the entry section 13, which can hardly be performed other than deliberately, and thus limits to a particular extent the risks of the plug falling.

The lateral partition of the engagement chamber 32 of the key in Figures 4 and 5 also has two diametrically opposed holes 34 which bring the chamber into communication with the outside and extend in a longitudinal diametric plane of the body 31 of the key. These two holes form guide slides in which lateral limbs 51 of a slide 50 passing through the body 31 of the key from one side to the other are inserted and whereof parts of the limbs 51 which protrude outside the body of the key form the retractable pegs 52.

The device for retracting the slide 50 and thus the pegs 52 is a drawing device comprising a screw 53 which extends axially within the body of the key and whereof the head is housed in a hollow 54 within the slide, opening into the side of the slide adjacent to the free end of the body of the key and opening up the engagement chamber 32 of the key to an extent sufficient for fitting of the key onto the pivot pin not to be hindered by the presence of the slide; the threaded body of the screw 53 opens into the region between the limbs of the head 30 forming the handle, and its free end is screwed into an internally threaded hole extending radially within a manoeuvring ring 55.

In order to allow the slide 50 to be retracted to the base of the holes 34 or close to the base, and to allow the screw 53 to pass through, the body 31 of the key has a bere 36 prolonging the engagement chamber 32 into the vicinity of the end of the body connected to the head 30 of the key. The diameter of this bore 36 is sufficiently large to house a resilient restoring member 56 such as a helical spring with non- contiguous coils wound around part of the length of the body of the screw 53, whereof the length is selected such that when the free end of the slide 50 is approximately flush with that of the body of the key and when the manoeuvring ring 55 bears against the opposite end of the body, it for its part bears, without being compressed, at one end against the slide and at the opposite end against the base of the bore 36.

As in the previous embodiment, if the lock is a quarter-turn lock, the plane in which the holes and in this case the slide extend and the diametric plane of the body in which the fixed pegs 33 extend intersect at a right angle.

When the pivot pin 2 is in the position of complete locking (against the stop), it is possible at the same time to fit the key 3 around it and to slide the fixed pegs 33 thereof in the notches 12, while the slide moves up again as a result of the presence of the upper partition 10 of the plug; then, once the fixed pegs 33 are beyond the notches, the key can be turned towards the freeing position of the latch, the retractable pegs 52 slide on the partition until the freeing position is reached, the key and the pivot pin still being fitted together and engaged, at this point the retractable pegs 52 in their turn face the notches 12 and, under the force of the restoring spring 56, are pushed along the entry section 13 of the ramp.

The result is that in this freeing position any rotation of the key and the pivot pin in the opposite direction is prevented unless the pegs 52 are retracted by acting on the manoeuvring ring 55 in opposition to the force of the restoring member 56. Thus it is possible to use the head 30 of the key as a handle to raise the plug 1 absolutely safely. To disengage the key from its fitting, first of all it is necessary to retract the retractable engagement pegs 52 and then to turn the key to the locking position of the latch by sliding the fixed pegs 33 in the retaining section 14 of the ramp and then to draw the key in order to slide the fixed pegs 33 in the entry section 13.

While in order for the embodiments of Figures 1 to 5 to be used they require the key to be in a predetermined position with respect to the hole in the plug (first "indexing") and moreover they require it to be at the same time in a predetermined position with respect to the head of the pivot pin (second "indexing"), which is not achieved if the pivot pin has been turned accidentally, in which case the pivot pin has to be put back into the correct position by makeshift means, the embodiments of Figures 6 to 11 are devices with single indexing.

In these embodiments, as in the previous ones, the pivot pin 2, which passes through at least part of the thickness of the plug 1 (Figure 11), extends along a pivot axis perpendicular thereto; to fix the pivot pin to the plug, the latter has in its lower region (when it is in the position of closing off the shaft) a partition part which is pierced by a hole passed through by the pivot pin and is located between two fixing elements which in this case are formed above the partition by the base 20 of the pivot pin, this base being separated from the partition by a gasket forming a restraint to prevent accidental unlocking of the pivot pin and below by tabs of the pivot pin pressed down by force against the latch, which is itself adjacent to the partition; the pivot pin is prolonged above the base by a head 21 extending along the pivot axis.

On the other hand, contrary to the previous embodiments, it is not necessary for the plug to have another partition above the fixing partition, since the ramps are made in the head 21 of the pivot pin (Figure 6) in order also to co-operate with the engagement pegs of the lateral partition of the engagement chamber of a key, but in this instance extending radially towards the inside of the chamber.

To be more precise, the head 21 of the pivot pin 2 in this case has a generally cylindrical shape of circular cross-section and has in its lateral surface at least one groove, in this case two diametrically opposed grooves, intended for the pegs to pass through. Each groove opens at the free end of the head 21 in a notch 22 whereof the wall forms an entry guide ramp section 23 extending in the same direction as the pivot axis, and is hollowed out below a lip 24 of the pivot pin whereof the lower face forms a retaining guide ramp section 25 extending in a plane perpendicular to the pivot axis and circumferentially around this axis, along an arc, in this case having a value close to 90°, but capable of being either larger or smaller where appropriate; the end of the circumferential arc over which the groove extends takes the form of a face forming a stop 26 for the peg of the key.

The key 3 illustrated in Figures 7 and 8 and that in Figures 9 and 10 are intended to actuate rotation of the pivot pin 2 of Figures 6 and 11. To this end, they have at one end a head 30 and, starting from this head 30, an elongate body 31 extending along a pivot axis intended on actuation of the pivot pin to become congruent with the pivot axis thereof. At the free end of the body 31, opposite the head 30, a chamber 32, in this case of generally cylindrical shape, opens up, extending along the pivot axis and slightly larger in its dimensions than those of the head 21 of the pivot pin 2 such that the chamber 32 can engage in a fitting condition with the head 21.

The lateral partition of the engagement chamber of the keys in Figures 7 to 11 has flush with its free end two diametrically opposed pegs 33 extending radially inwards and in the direction of the longitudinal axis of the chamber.

The result of this construction, contrary to the embodiments of Figures 1 to 5, is that whatever the position of the pivot pin, from its position of locking against a stop to its position of freeing against a stop, it is possible to fit the engagement chamber 32 of the key to the engagement head 21 of the pivot pin simply by sliding the pegs 33 in the notches 22. Moreover, in this instance, rotation of the key, which brings about sliding of the pegs 33 in the groove, does not cause any rotation of the pivot pin, since the pegs 33 have not reached the stop face 26, as a result of the shapes given to the chamber and the head.

In a similar manner to the embodiments of Figures 1 to 5, according to the invention, on the one hand the disengagement from fitting between the keys 3 in Figures 7 to and the pivot pin 2 in Figure 6 is made impossible when the pegs 33 are engaged below the upper lip, in this instance of the pivot pin after rotation of the key, unless the latter is made to perform a previous rotation in the opposite direction, and on the other hand the engagement region of the key has one or more retractable engagement pegs intended to prevent a rotation of this kind in the opposite direction.

Thus, the key illustrated in Figures 7 and 8 has, like that in Figures 2 and 3, a retractable peg, and that illustrated in Figures 9 and 10 has two retractable pegs, like that in Figures 4 and 5.

Because the key in Figures 7 and 8 has a very great number of points in common with that in Figures 2 and 3, only those features which differ from the corresponding features of the key in Figures 2 and 3 will be described in detail below; the corresponding elements are designated in the drawings and in the description by the same reference numerals. Apart from the fact already mentioned, that in the embodiment of Figures 7 and 8 the fixed engagement pegs 33 are inside and not outside, and that the chamber 32 is otherwise of generally cylindrical shape and not polygonal, the essential difference relates to the pivotal lever 41 and its environment.

In fact, as in this case the peg 42 is intended to engage in a notch 22 in the pivot pin 2, this peg must also project inside the chamber 32. The result is that, of the holes 34, the one which does not extend between the projections 35 where the ends of the pin 40 are housed opens at the free end of the head 31 to provide a way for the lever 41 to pass through. Thus, the lever 41 is movable between a position in which it bears against a wall of the hole 34 extending between the projections 35 and a position in which it is raised close to the opposite wall of the holes 34; as a function of the position of the lever 41, a larger or smaller part of the peg 42 projecting downwards extends between the lateral walls of the hole opening out at the free end of the body 31; when the lever bears against the lower wall of the other hole this peg 42 protrudes approximately as far into the chamber 32 as the fixed peg 33, and it is flush with the free end of the body 31.

Thus, when the chamber 32 is opposite the head 21 of the pivot pin and the fixed pegs 33 are opposite the notches 22, it is possible at the same time to fit the key around the pivot pin and to slide the fixed pegs thereof in the notches, while the retractable peg 42 moves up again; then, once the fixed pegs 33 have reached the groove in the head 21, the key can be turned, the fixed pegs sliding along the retaining ramp sections 25 and the retractable peg 42 sliding on the pivot pin, while the latter remains immobile; once the retractable peg 42 in its turn faces a notch 22 it is pushed, under the restoring force of the spring 44, along the entry section 23 of the ramp.

The result is that in this position any rotation of the key independently of the pivot pin is prevented unless the peg 42 is retracted by acting on the manoeuvring finger 43; continuing the movement of the key in the same direction, as a result of pushing the fixed pegs 33 on the stop face 26, carries the pivot pin towards the freeing position of the latch, with the key and the pivot pin still being fitted together and engaged; it is then possible to use the head 30 of the key as a handle to raise the plug 1. To withdraw the key, first of all it is necessary to retract the retractable engagement peg 42 and then to turn the key until the fixed pegs 33 reach the base of the notches 22 and to draw the key in order to slide the fixed pegs 33 along the entry section 23.

Similarly, because the key in Figures 8 and 10 has a very great number of points in common with that in Figures 4 and 5, only those features which differ from the corresponding features of the key in Figures 4 and 5 will be described in detail below; the corresponding elements are designated in the drawings and in the description by the same reference numerals. Apart from the fact already mentioned, that in the embodiment of Figures 9 and 10 the fixed engagement pegs 33 are inside and not outside, and that the chamber 32 is otherwise of generally cylindrical shape and not polygonal, the essential difference relates to the slide 50.

In this case, simply, the lateral limbs 51 of this slide 50 do not have parts protruding outside the body of the key, but in contrast parts protruding into the chamber 32 which form the retractable pegs 52.

As a result, when the fixed pegs 33 are opposite notches 22 in the pivot pin, it is then possible at the same time to fit the key 3 around the pivot pin and to slide its fixed pegs 33 in the notches 22, while the slide moves up again; then, once the fixed pegs 33 are beyond the notches, the key can be turned, the retractable pegs 52 slide on the pivot pin until they themselves face the notches, and they are pushed, under the restoring force of the spring 56, along the entry section 23 of the ramp. The result is that in this position any rotation of the key with respect to the pivot pin is prevented unless the pegs 52 are retracted by acting on the manoeuvring ring 55 in opposition to the force of the restoring member 56. Thus, it is possible to use the head 30 of the key as a handle to raise the plug 1 or more generally the covering element absolutely safely. To disengage the key from its fitting, first of all it is necessary to retract the retractable engagement pegs 52 and then to turn the key until the fixed pegs reach the notches 22 by sliding them in the retaining section 25, and then to draw the key in order to slide the fixed pegs along the entry section 23.

It will be noted that with these embodiments the key may be put into the fitting and engagement condition with the pivot pin whatever the position of the latter, and may also be separated whatever its position, thanks to the fact that there is only one indexing.

Figure 11 illustrates a locking device having a pivot pin 2 according to Figure 6 and a latch 6 in the locking position below a stop 70 of the frame 7, and a removable key such as that in Figures 9 and 10, the pivot pin and the key being fitted together.

It goes without saying that the invention is not restricted to the embodiments above described and shown, and it would be possible to provide others without departing from the scope thereof, in particular embodiments in which the head of the pivot pin, the engagement chamber, the grooves and the pegs have particular geometric shapes in order that a given covering element may be opened only by a single predetermined type of key.

Claims

PCT/FR00/01533 CLAIMS

1. A device for locking a covering element to a support frame |, comprising a pivot pin which extends along a pivot axis passing through the thickness of the covering element, and has on one side of the covering element an end region where a latch is fixed and on the other an end engagement region, and a removable key having an end engagement region having at least one engagement peg adapted to co-operate with a respective ramp of the covering element or of the pivot pin comprising an entry 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 engagement region of the pivot pin and that of the key being adapted to fit together when the peg is slid towards the fixing end of the latch along the entry section and disengagement from fitting together being made impossible when the key is subsequently rotated about the pivot axis and the peg has then been slid along the retaining section unless the key is made to perform a previous rotation in the opposite direction, characterised in that the engagement region of the key moreover has at least one retractable engagement peg which is urged by a resilient restoring member towards the free end of the engagement region of the key in order, after the engagement regions have been fitted together and the key has been rotated by a predetermined angle, to engage in the entry section and thus to prevent the key from rotating in the said opposite direction, that is to say in the direction allowing disengagement from fitting together, unless the retractable peg is retracted in opposition to the force of the restoring member.

2. A device according to Claim 1, characterised in that in order to co-operate with a hole ) provided in a partition of a covering element , this hole having at least one notch whereof at least a part forms an entry ramp section and being bordered by lips whereof at least a lower face region forms a retaining ramp section , the key comprises an elongate body extending along a pivot axis and having, close to a free end where the engagement region is disposed, at least one fixed engagement peg extending radially outwards with respect to the axis and at least one retractable engagement peg also extending radially outwards with respect to the axis. AMENDED SHEET

PCT/FR00/01533

3. A device according to either of Claims 1 and 2, characterised in that the retaining ramp section is part of a groove hollowed circumferentially out of the covering element around the pivot axis and limited by a stop face for the fixed peg of the key.

4, A device according to any one of Claims 1 to 3, characterised in that the engagement region of the pivot pin and the engagement region of the key have polygonal cross-sections which are approximately similar in shape and adapted to be brought into the fitting-together condition.

5. A device according to any one of Claims 1 to 4, characterised in that the engagement region of the key has a generally prismatic shape extending along the pivot axis of the key, whereof the cross-section has a polygonal shape.

6. A device according to any one of Claims 1 to 5, characterised in that the engagement region of the key has a chamber of generally prismatic shape which extends along the pivot axis of the key and has a polygonal cross-section, and which is adapted to be fitted around a head of the pivot pin of similar shape.

7. A device according to any one of Claims 1 and 4 to 6, characterised in that in order to co-operate with a head of the pivot pin having at least one notch whereof at least one wall forms an entry ramp section and at least one lip whereof at least one lower face region forms a retaining ramp section , the key comprises an elongate body extending along a pivot axis and having, close to a free end where the engagement region is disposed, at least one fixed engagement peg extending radially inwards with respect to the axis and at least one retractable engagement peg also extending radially inwards with respect to the axis.

8. A device according to any one of Claims 1 and 4 to 7, characterised in that the pivot pin has a head of generally cylindrical shape of circular cross-section having in its lateral surface at least one groove opening at a free end of the head in a notch whereof at least one wall forms an entry guide ramp section , this groove being hollowed out below a lip of the pivot pin whereof the lower face forms a retaining guide ramp section . AMENDED SHEET

PCT/FR00/01533

9. A device according to any one of Claims 6 to 8, characterised in that the head of the pivot pin has a stop face for the fixed peg of the key.

10. A device according to any one of Claims 1 and 4 to 9, characterised in that the engagement region of the key has a chamber of generally cylindrical shape which extends along the pivot axis of the key and is adapted to be fitted around a head of the pivot pin of similar shape, and in which at least one fixed peg and at least one retractable peg extend.

11. A device according to any one of Claims 1 to 10, characterised in that the key comprises a body having an engagement region having a chamber adapted to be fitted around a head of the pivot pin and having two diametrically opposed holes bringing the chamber into communication with the outside and extending in a longitudinal diametric plane of the body, and a retractable element housed partly in these holes and bearing at least one peg .

12. A device according to Claim 11, characterised in that the retractable element is a pivotal lever .

13. A device according to Claim 12, characterised in that the pivotal lever has a manoeuvring finger projecting outside the body and a face of this lever is urged by a spring bearing against it, forming the resilient restoring member of the retractable

Peg.

14. A device according to Claim 11, characterised in that the retractable element is a slide .

15. A device according to Claim 14, characterised in that the key has a drawing device comprising a screw whereof the head is housed in a hollow within the slide, a manoeuvring ring into which the free end of the threaded body of the screw is screwed, and a helical spring surrounding part of the body of the screw and forming the resilient restoring member of the retractable peg.

16. A device according to any one of Claims 1 to 15, characterised in that the key has a head formed in the shape of a handle. AMENDED SHEET

PCT/FRO0/0153 3

17. A device for locking a covering element to a support frame, substantidly as herein described with reference to and as illustrated in Figures 1 to 5 or Figures 6 to

11. AMENDEDMENT DATED THIS 18™ DAY OF FEBRUARY 2002 JOHN & KERNICK FOR THE APPLICANT