EP0174933A1 - Releasable coupling device - Google Patents

Abstract

A releasable coupling device (10) has two components (12, 14). The component (14) comprises a socket (70) having two axial pins inside (76). The component (14) comprises a housing (24) which can be inserted into the socket (70) so that the pins (76) enter the housing (24) through openings (80) provided in this housing, so as to lock the pins with locking members (26) in the housing. A movable release member (42) slidable in the housing (24) extends from the housing to receive a coin. When a coin has been inserted, the release member (42) can slide in the housing so that the coin (50) engages another release member (40) which acts on the locking members (26 ) to unlock the pins (76) and thus allow the components (12, 14) to be separated by extracting the housing (24) from the socket (70). During this sliding of the release member (42), the coin (50) is introduced into the housing (24) and is captured therein by locking the release member (42) by engagement of an internal locking member (54) in the housing (24). A locking member (90) extending from the housing (24) is coupled between its ends to the locking member (54) and can be moved so that a pressure roller (100) on the inner end of the member (90) engages a pin (76) when the latter projects into the housing (24) by coupling of the components (12, 14). The locking member (90) is neutralized when the components (12, 14) are uncoupled so that a captured coin cannot be removed from the housing (24) until the components (12, 14) are coupled to each other again.

Description

RELEASABLE COUPLING DEVICE

This invention relates to a releasable coupling device.

The object of the invention is to provide a releas¬ able coupling device having two components releasably lockable one to the other and which can be released only when one of the components is conditioned by positioning a suitable keying means, such as a token, therein and which is arranged'so that when the components are separated the keying means is captured within the retaining component such that it cannot be removed until the components are again coupled together.

Coupling devices in accordance with the invention are usable, inter alia, in connection with hiring of articles. In this instance, one of the components of the coupling device is arranged at a fixed location and the other is attached to an article to be hired. The token may be a coin. The articles to be hired are normally connected to the fixed location by interconnec¬ tion of the two coupling components and a person intend- ing to use the article can free the article from the fixed location by manipulation of the coupling device

OMΛ. only after insertion of a coin. Thereafter, the coin is captured by one of the components of the coupling device and cannot be retrieved until the hired article is returned to the fixed location and the coupling com- ponents coupled together again. In a particular appli¬ cation, the fixed location is associated with a super¬ market and the articles to be hired may comprise super¬ market trolleys.

In accordance with the invention there is provided a releasable coupling device comprising first and second coupling means releasably couplable together in latched interengagement, said second coupling means including release means operable to release said latching interen¬ gagement, to permit separation of said coupling means one from the other, only when a removable key means is received by said second coupling means, said key means being retained against removal from said second coupling means when received thereby and when said release means is operated. The invention is further described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic perspective view of a supermarket trolley hire installation utilising coupling devices constructed in accordance with the invention;

Figure 2 is a cross sectional view of one coupling component of a coupling device of Figure 1, conditioned for release from the other component of the device;

Figure 3 is a fragmentary cross section correspond- ing to a portion of Figure 2, but showing disposition of internal parts within the coupling component of Figure 2 when interengaged with another coupling component of the coupling device of Figure 1;

Figure 4 is a fragmentary cross sectional view corresponding to part of Figure 2, but showing the two coupling components of the coupling device of the invention coupled together;

Figure 5 is a scrap section on the line 5-5 in Figure 2;

Figure 6 is a scrap section on the line 6-6 in Figure 2;

Figure 7 is a scrap section on the line 7-7 in Figure 2;

Figure 8 is a fragmentary cross sectional view showing a modified form of one coupling component formed in accordance with the invention;

Figure 9 is a cross section substantially on the line 9-9 in Figure 8;

Figure 10 is a view like Figure 9 but showing the coupling component in a different condition; Figure 11 is a fragmentary cross sectional view of one coupling component of the invention modified in another way;

Figure 12 is a diagrammatic perspective view of a a mobile station for receiving supermarket trolleys, formed in accordance with the invention; and

Figure 13 shows an alternative form of receiving station for supermarket trolleys, together with trans¬ porting apparatus, formed in accordance with the invention. Referring firstly to Figure 1, coupling devices 10 constructed in accordance with the invention are shown

OMPI as comprising first and second coupling means in the form of first and second coupling components 12, 14 respectively. Components 12 are attached in side by side position to a latching bar 20 which is arranged at a fixed location. These exemplary coupling devices 10 are intended for use in conjunction with a supermarket, where trolleys 22 are releasably lockable to the latch¬ ing bar 20 by use of the coupling devices 10. Thus, the coupling components 14 are secured by means of a chains 16 to the trolleys 22 and the latching bar 20 is mounted by posts 21 above a ground surface over which the trolleys 22 are movable. Broadly speaking, the arrange¬ ment is such that, initially, the coupling components 12, 14 of each coupling 10 are interconnected together and are releasable one from the other only when a user inserts a coin into the coupling component 14. When so inserted, the coin is retained in the coupling component 14. After release of the component 14 from the compo¬ nent 12, the associated trolley is freed for use and after use the user returns the trolley to the location of the latching bar 20 and re-effects coupling between the components 12 and 14, whereupon the coin is returned to the user. By virtue of the arrangement the trolleys 22 are, when the components 12, 14 of each coupling device are connected together, positionable in side by side arrangement each secured to the latching bar 20. This provides easy access thereto by users.

Reference is now made to Figure 2 to 7 which show one coupling device 10 in more detail. In Figure 2 , the component 14 of this coupling device 10 is shown in the condition which it adopts after release from the

OMPI component 12, following insertion of a coin into compo¬ nent 74.

The component 14 has a flat rectangular casing 24 formed in two parts 24a, 24b which are secured together in a tamper proof manner, such as by welding or the like. One end of chain 16 is secured to the casing 24.

Within the interior of the casing 24 there are provided two first latching members 26, the purpose of which is described in more detail later. These are pivotal about respective axes extending transversely of the major surfaces of the casing, each having a hub 26a which has projecting spigots 26b retained in recesses 28 on opposed internal faces of the casing 24. Members 26 are thus rotatable about the axes of the respective spigots 26b and these axes are positioned adjacent one another and towards one end of the casing 24. The members extend from the respective hubs to outer ends 26c. A helical compression spring 30 is positioned between the members 26 and resiliently biases the members 26 away from each other, that is to say in opposite rotational directions around the respective axes of rotation. In the condition shown in Figure 2, however, the two members 26 are held, against this resilient bias, in locations where the outer ends 26c of the members are adjacent each other. This holding is effected by pressure applied to the ends 26c through respective engaging camming surfaces 40a, 40b arranged in divergent facing relationship on a bifurcated end of a first release member 40 provided within the casing 24. The member 40 is slidable lengthwise of the casing 24 towards and away from the members 26.

OMPI * Member 40 is itself carried within a guideway 42a extending lengthwise of a second release member 42, in the fashion shown more particularly in Figure 5. Member 42 is guided for lengthwise movement by guides 44 on internal faces of the casing 24. Although members 40, 42 are freely slidable one relative to the other, in the condition of Figure 2 the member 40 is held in the position shown (where it acts against the bias of spring 30 to hold the members 26 with ends 26σ adjacent) by means of an interlocking between the members 40 and 42 and of an interlocking between the casing 24 and the member 40. The interlocking between the members 40 and 42 is provided by a coin 50 which is received within the member 42 in a sidewardly open slot 52 or member 42. When so received, the coin 50 is positioned between an end face 60 of member 40 and one opposite edge face 52a of slot 52. The interlocking between the member 42 and the casing 24 is provided by means of a locking element 54, which element is retained between the opposed internal faces of the casing 24, and by guideways 56 formed on these internal faces so as to be movable transversely of the direction of movement of member 40. At the position shown in Figure 2, an end of the locking element is received within a sidewardly open recess 62 in member 24 so as to block movement of member 42. The locking element 54 is resiliently biased to this posi¬ tion by a helical compression spring 110 between a side wall 65 of casing 24 and an end of the locking element opposite the end engaged in the recess 62. The member 42 extends at one end 42b through an opening 64 in a wall 61 at an end of the casing 24 remote from the members 26, so as to be movable on its allowed path of movement through this opening. In the position of Figure 2, however, the member 42 is at an extreme of its movement inwardly into the casing 24 so that end 42b projects only slightly from the casing 24, the member 42 being locked in this position by the previously described engagement of locking element 54 in recess 62. In this position, the coin 50 is moved with the member 42 so as to be within the casing 24 in a fashion such that it cannot easily be removed, that is say, the coin 50 is captured within the casing 24. The coupling component 12 is in the form of a socket 70 which is secured to bar 20. Socket 70 has a base 72 and an upstanding peripheral wall 74. Two prongs 76 extend within the socket 70, projecting from base 72 in a direction towards an open mouth defined by the periphery of the wall 74. The prongs 76 have, at- their end portions, respective outer, sloping, camming surfaces 76a. Prongs 76 also have, at opposed inner faces thereof, respective cutout portions 76b which define transverse surfaces 76c on the prongs. The coupling component 14 is positionable on the component 12 by inserting the end of the casing 24 opposite that from which member 42 extends into the socket 70, this being effected by movement through the open mouth of the casing defined by the periphery of wall 74, in the direction of extent of the prongs 76. During this movement, the free ends of the prongs pass into the casing 24 through openings 80 in the casing, these openings being in an end wall 63 of the casing opposite the end wall 61 of the casing from which member 42 projects. The openings 80 are normally closed by spring loaded flaps 84, but by camming action against the camming surfaces 76a, these flaps 84 are swung inwardly during insertion of the component 14 into the component 12. When components 12 and 14 are so positioned, the prongs 76 are positioned relative to the members 26 and member 40 in the fashion shown in Figure 3. It will noted that the surfaces 76c on the prongs 76 are located adjacent to outstanding transverse step surfaces 26d on the members 26, the prongs themselves being outwardly disposed relative to the respective members 26.

Component 14 is provided with a locking member 90. This has an elongate stem 92 which extends from an enlarged head portion 94 positioned exteriorly of the casing 24, into casing 24 through an opening 96 in the end wall 61 of the casing adjacent the opening 64 , thence inwardly, through an opening 98 through locking element 54 to an inner end which carries a roller 100. The member 90 is axially slidable but is biased to an outer position, shown in Figure 2, by means of a helical compression spring 102 positioned between a flange 104 on the stem 92 of member 90 and an internal partition wall 106 within the casing 24. The outward movement of member 42 under influence of spring 102 is limited, to position the member 90 at the location shown in Figure 2, by engagement of flange 104 with the end wall 61 of casing 24.

In the condition shown in Figure 2, the roller 100 is positioned adjacent the end of member 40 which carries the camming surfaces 40a, 40b. Although the opening 96 is made oversized relative to the cross section of the stem 92 of member 90, whereby to permit the locking member 90 to swing somewhat, particularly to allow the lower end thereof and roller 100 to move laterally (as viewed in Figure 2) relative to members 40 and 42, such swinging movement is largely precluded by virtue of stem 92 of member 90 passing through the opening 98 in locking element 54 and by virtue of the fact that the locking element 54 is substantially immovable under influence of the member 90, by virtue of the locking element 54 being urged by spring 110 to the position shown in Figure 2 at which it engages the recess 62 to hold member 42 in position.

In the position shown in Figure 2, the locking member 90 may be depressed against action of spring 102, but such depression has no effect on the coupling device. On the other hand, it will be observed that, in the configuration of Figure 3, one of the prongs 76 is positioned adjacent the roller 100 on member 90, being adjacent the camming surface 76a on that prong. Accord- ingly, if, in this condition, the locking member 90 is depressed, the roller 100 will engage that camming surface 76a. The camming surface 76a is sloped so as to cause the roller 100 to move laterally away from the members 40 and 42 as such movement occurs. As a result of this, the locking member 90 is swung somewhat about the location where the member passes through opening 96 in wall 61 of casing 24. This swinging, which is counterclockwise as viewed in Figure 2, causes the stem 92 of locking member 90 to engage a side surface of the opening 98 in locking element 54 and causes the locking element 54 to be moved laterally away from the member 42

OMPI thus disengaging element 54 from recess 62. This movement of the locking element 54 occurs against resilient bias provided by the spring 110.

A helical compression spring 120 is positioned within a lengthwise extending groove 122 on one face of member 42. One end of the spring 120 bears against an end face 122a of the groove 122 whilst the other bears against a fixed projection 124 on casing 24. Under the condition of release of the locking element 54 from the recess 62, the spring 120 (which was previously com¬ pressed by an action described later) operates to press against end surface 122a to force the member 42 to move in its lengthwise direction whereby the end 42a is caused to move outwardly through the end wall 61 of casing 24 to the position shown in Figure 4, at which the slot 52 is positioned externally of the casing. In this position of member 42, the coin 50 may be readily freed from the coupling component 14 by sideward move¬ ment from the slot 52. The outward movement of the member 42 under influence of spring 122 is limited by engagement of a projection 130 on member 42 with an end wall on casing 24.

Consequent upon the movement of member 42 to position slot 52 exteriorly of casing 24, the member 40 is no longer held against lengthwise movement and the spring 30 then acts against the members 26 to pivot the members 26 about the axes of respective spigots 26b so that the ends 26c are moved outwardly away from each other, with the ends 26c of the members thus press the against surfaces 40a, 40b of member 40 whereby, by camming action between the ends 26c and surfaces 40a, 40b to force the member 40 away from the pivot axes of the members 26 in the direction towards end wall 61 of casing 24. This movement is able to continue until the ends 26c pass outwardly of the extremities of the surfaces 40a, 40b and the ends 26c reach abutting contact with opposed surfaces of the respective prongs 76. At this position, too, the outwardly directed step surfaces 26d of the members 26 are mounted to be located under the surfaces 76c of the prongs 76, so that the pairs of surfaces 76c, 26c provide a coupling intercon¬ nection between the members 26 and prongs 76 which prevents movement of the members 26 outwardly away from the prongs 76. In this way the casing 24 and coupling component 14 are latched to the coupling component 12. Once the action above described has been completed and the member 42 has been moved outwardly with con¬ sequent engagement of the prongs 76 and members 26, the member 90 will, if no longer depressed, be returned to its initial position under influence of spring 102. Then, the spring 110 will act to move locking element 54 from right to left as shown in Figure 4 to position it and the member 90 approximately at the positions approx¬ imately shown in Figure 3. In this condition, however, the member 42 is positioned as shown in Figure 4, so that the lower end of member 42 is positioned well above and clear of the locking element 54. This movement of locking element 54 is accompanied by swinging back of the locking member 90, the swinging of the locking member and movement of the locking element 54 being limited by abutting engagement of stem 92 of member 90 with one of the guides 44. In order to release the component 14 from the component 12, coin 50 is reinserted in slot 52 and member 42 depressed inwardly. The inward movement of the member 42 is effected against resilient bias of spring 120 which is compressed during this movement.

During this movement, too, a sloping cam surface 132 on the end of release member 42 engages a sloping cam surface 134 on the end of locking element 54 so as to force the locking element 54 laterally outwardly away from member 42 against action of spring 110. This movement continues until the recess 62 is positioned directly oppose the locking element 54 at which time the locking element 54 is moved under influence of spring 110 to enter the a recess 62 to lock the member 42 back in the position shown in Figure 2. Also during this movement, the coin 50 engages the free end of the member 40 opposite the camming surfaces 40a, 4Qb so that the member 40 is carried with the member 42 and moved whereby the camming surfaces 40a, 40c engage the ends 26c of the members 26 and by camming action therewith force these inwardly towards each other. Thus, the members 26 are moved to again occupy the position shown in Figure 3, at which the surfaces 26d on the members 26 are freed from cooperation with the surfaces 76c on the prongs 76. In this condition, then, the coupling component 14 may be directly withdrawn from the coupling component 12.

Whilst the arrangement described is suitable for use in the described context of a supermarket, the coupling device 10 may, of course, be utilized for other purposes. While the device 10 is a coin free device, it will be appreciated that it may, equally, be operated by insertion of a suitable token of other kind in the slot 52. Indeed, the slot 52 may be configured to receive any desired keying means. Again, whilst the described arrangement has the coupling component 14 secured to the trolley 22 or other article to be hired, the arrangement could, of course, be reversed, with the component 14 arranged at a fixed location, such as secured to bar 20, and component 12 attached to the trolley or other article, such as by means of the chain 16 shown.

In Figures 8 and 9, a modified form for the first release member 40 is shown. Here, member 40 is shown as having, at the end closest to end wall 61 of casing 24, a pair of opposed cutouts 140. When the member 40 is pushed away from latching members 26 under action of spring 30, these cutouts 140 are engaged by two laterally spaced abutments 144 provided on a pivotal latch element 142. The latch element 142 is of generally U-shaped configuration having a pair of side arms 142a, 142b which at their free ends are pivotally mounted to casing 24 adjacent opening 64 in wall 61. The other ends of the arms 142a, 142b are bridged by an interval cross portion 142c which underlies member 40 and which carries the abutments 144. Springs 146, of which only one is shown in the drawings, act between casing 24 and the ends of the arms 142a, 142b away from the pivot axis of element 142. These springs bias the ' element 142 towards the member 40 and hold the element 142 in position where the abutments 144 are retained in the cutouts 140. The element 142 is, however, provided with a pair of ramps 148, one on each of the arms 142a, 142b. As shown in Figure 10, these ramps are arranged to be engaged by a coin 50 when in position on member 40 so that as the member 42 is depressed inwardly within the casing 24 the coin engages the ramps 148 to depress the element 142, against bias of spring 146 whereby to pivot the element 142 away from the member 40, so releasing the abutments 144 from the cutouts 140. Thus, although the element 142 normally holds member 40 in a position where it cannot be moved in its lengthwise direction, this holding is released when a coin 50 is inserted into the member 42 and the member 42 properly advanced to effect operation of the coupling component 14. The provision of the element 142 assists in providing a positive locking of the member 40 in its released position so as to render it more difficult for persons to effect release of the component 14 from the component 12 by insertion of an object through the opening 64 to engage the member 40 and effect depression thereof. More particularly, the element 142 is made of material having substantial resilient flexibility so that pressure is required on both ramps 148 in order to permit sufficient movement of the portion 142σ and abutments 144 to effect release of the both abutments from the cutouts 140. If, for example, an object were to be passed down the opening 64 between the.two arms

142a, 142b, considerable difficulty would be encountered in engaging the element 142 in a fashion such as to permit movement thereof. Again, an object of less side to side width than the coin 50, will not evenly engage both ramps 148 during insertion to permit proper withdrawal of both of the abutments 144 from the cutouts 140.

Figure 11 shows a still further modification of the component 14 designed to inhibit internal manipulation of the component 14 when a coin is retained therein and the component has been freed from component 12. In particular, it will be seen from Figure 3, for example, that if an appropriately shaped object were to be pushed upwardly through the lower opening 80 in casing 24 immediately below the member 90, it may be possible to so engage the lower end thereof or the roller 100 as to effect swinging movement of the member 90 to release the locking element 54 from the recess 62 thereby permitting the member 42 to be moved under influence of spring 120 such that the end 42b of that member is projected outside the casing, together with any coin retained thereby. In Figure 11, the component 14 is shown modified by the inclusion of a blocking element 150 which is slidably mounted (by means not shown) on the inner surface of the side wall 65 of the casing, adjacent the lower end of member 90 and adjacent the roller 100. The element 150 has a portion 150a which extends in end to end direction of the casing 24 and, at one end of portion 150a, a sidewardly extending exten- sion 150b which extends in the direction away from wall 65 towards roller 100. The element 150 is movable in the end to end direction of the component 14 but, in the condition shown in Figure 11, the element 150 is biased by a helical compression spring 152 to a position where extension 150b is directly aligned in a side to side direction with the roller 100. In the condition shown in Figure 11, member 90 cannot be moved sidewardly to effect release locking element 54 from recess 62 because of the positioning of the extension 150b on element 150. That is to say, any attempt at sideward movement of the kind necessary to effect such release will be blocked by abutment between the extension 150b and the roller 100.

In the construction of Figure 11, the prongs 76 on component 12 are also slightly modified by incorporation of cutouts at the free ends thereof, which cutout^'s define transverse surfaces 154. These surfaces are so positioned that, during entry of the prongs 76 into the casing 24 during normal bringing together of the compo¬ nents 12 and 14 the end of portion 150a of element 150 closest towards end wall 63 of the component 14 is engaged by a surface 154 on one of the prongs 76. As a result of this, the element 150 is, during bringing together of the components 12 and 14 moved against action of spring 152 in a direction away from end wall 63 whereby the element 150 is moved to the position illustrated in part by phantom lines 150' . In this position, the abutment 150b is no longer directly aligned in the side to side direction with roller 100 so that sideward movement thereof is permitted to effect release of the locking element 54 by depression of member 90, in the fashion previously described.

In Figure 12, a transportable trolley receiving station 200 is formed by a trolley 201 formed of a rigid framework having ground wheels 202 and a tow structure 203 by which the trolley 201 can be coupled to a tractor or the like for towing the trolley about a ground surface. Components 14 of coupling devices 10 are chained to respective supermarket trolleys 22 and are releasably conneσtable to components 12 secured to latching bars 20 carried by the trolley 201. Thus, in use, the trolleys 22 may be positioned, for example, in the parking area associated with a supermarket, and users having made use of a trolley 22 may couple the trolley 22 to the trolley 201 by attachment of the component 14 associated therewith to one of the components 12. Thus, at the supermarket carpark, the trolleys may be accumulated at the station 200. When a sufficient number of trolleys have been so accumulated, a tractor or other vehicle may be attached to tow structure 203 and the attached trolleys taken back to a location within the supermarket at which the station 200 would be positioned for receipt therefrom of the trolleys by users, in the supermarket. Alternatively the trolleys 22 could be moved to a suitable storage location such as a secure overnight storage building. in Figure 13, a latching bar 20 having a plurality of coupling components 12 attached thereto is releasably secured to upright posts 21 by means of pins 210 which pass through apertures in the posts and bar 20 and which receive padlocks 211 for securing the bar 20 to the post 21. In this arrangement, the bar 20 and associated posts function as a receiving station 220 for trolleys 22 in the same fashion as previously described in relation to Figure 12. In this instance, however, when a sufficient number of trolleys 22 have been accumulated on the latching bar 20, the latching bar 20 is removed from posts 21 and attached to a transportable trolley 225 comprising a framework 226 and ground wheels 227. The bar 20 is couplable to the trolley 225 by, for example, insertion into brackets 228 affixed thereto. In this way, the bar 20 and attached trolleys 22 can be transported in the same fashion as described in relation to the embodiment of Figure 12.

Of course, in the arrangements of Figures 12 and 13, the trolleys 201, 225 may be provided with their own prime movers instead of being arranged for towing by separate tractors. Arrangements such as those described in Figures 12 and 13 may be used in other applications, such as for example with luggage transport trolleys in railway stations or at airports. The trolleys 201, 225 could also designed to be moved by hand if desired.

These and many other modifications and variations may be made to the described arrangement without depart¬ ing from the spirit and scope of the invention as defined by the appended claims.

O

Claims

1. Releasable coupling device comprising first and second coupling means releasably couplable together in latched interengagement, said second coupling means including release means operable to release said latch¬ ing interengagement, to permit separation of said coupling means one from the other, only when a removable key means is received by said second coupling means, said key means being retained against removal from said second coupling means when received thereby and when said release means is operated.

2. Releasable coupling device as claimed in claim 1 wherein said first and second coupling means include respective first and second latching members which interengage to effect said latched interengagement; said second latching member being movable from a latching position, at which said latched interengagement is effected when the first and second coupling means are coupled together, to a release postion at which said interengagement is not so effected; said release means including a first release member movable to effect engagement of and movement of said second latching member to its release position, and a second release member movable between first and second postions and having a key means receiving portion for receiving said key means when said second release member is at its said first position, movement of said second release member to its said second position with said key means so received causing said first release member to be moved to effect said engagement of and movement of said second latching member to its release position.

3. Releasable coupling device as claimed in claim 2 including locking means operating automatically to effect locking of said second release member in its said second position on movement of the second release member to that position; said locking means being manipulatable to effect release of said locking when said first and second coupling means are coupled together, but not when said first and second coupling means are not coupled together.

4. Releasable coupling device as claimed in claim 3, said second coupling means including a receptacle into which said key means receiving portion of said second release member is moved when said second release member is moved from its first to its second position, whereby to effect said retention of the key means in the second coupling means by capture of the key means in said receptacle.

5. Releasable coupling device as claimed in claim 3 or claim.4 wherein said second latching member is resil- iently biased to its said latching position.

6. Releasable coupling device as claimed in claim 5 wherein said first release member and said second latching member have respective cam surfaces which

OMPI cooperate to drive said second latching member against said resilient bias thereof to its release position under said movement of the first release member.

7. Releasable coupling device as claimed in claim 6 wherein said first and second release members are slidable one relative to the other for the respective said movements thereof in a common direction, said first release member being moveable independently of said second release member, at least when the second release member is at its said first position.

8. Releasable coupling device as claimed in claim 7 wherein said second release member is resiliently biased to its said first position.

9. Releasable coupling device as claimed in claim 7 or claim 8 wherein said locking means includes a first locking portion movable laterally of the path of move¬ ment of the second release member to and from a locking position at which it engages a second locking portion on the second release member, for locking the second release member at its second position; said locking means including a locking member movable to effect movement of said first locking portion from said locking position, and engaging means cooperable with said first latching member, when said coupling means are coupled together, to guide said locking member for said movement thereof said first locking portion being resiliently biased into engagement with the second locking portion of said

OMPI

^' second release member, when the locking portions are engaged with each other, movement of said locking member to effect movement of the first locking portion from said locking position being effected against the resil¬ ient bias applied to said first locking portion.

10. Releasable coupling device as claimed in claim 9 wherein said locking member is lengthwise slidable on a path generally parallel to the paths of movement of said first and second release members, and carries said first locking portion, said locking member also being pivotal about a location towards an end thereof, the other end of the locking member carrying said engaging means in the form of a first camming surface which, under lengthwise movement of said locking member when the coupling means are coupled together, engages a second camming surface on said first latching member to swing said locking member about said location and to effect said movement of said first locking portion from its locking position.

11. Releasable coupling device as claimed in claim 10 wherein said locking member is resiliently biased in its lengthwise direction away from the first latching member when the coupling means are coupled together.

12. Releasable coupling device as claimed in claim 11 wherein said second coupling means includes a casing defining said receptacle and within which said second latching member, said first and second release means, said locking member and said first locking portion are retained, said one end of said locking member extending exteriorly of said casing and said locking member being depressible against the resilient bias applied thereto, to effect lengthwise movement thereof for engagement of said camming surfaces when the coupling means are coupled together, said key means receiving portion of said second release member extending exteriorly of said casing when said second release member is in its said first position and said second release member being depressible against the resilient bias applied thereto to move it to its said second position.

13. Releasable coupling device as claimed in claim 12 wherein said first latching member comprises a projec¬ tion on said first coupling means and said casing has an opening for entry of said projection thereinto to position the projection for latching engagement with the second latching member.

14. In combination, a plurality of coupling means as claimed in claim 1, one of first and second coupling means of each said coupling device being secured to a support member.

15. The combination of claim 14 wherein said support member is fixedly located relative to a ground surface over which mobile articles are movable, the other coupling means of each said coupling device being secured to respective ones of said mobile articles.

16. The combination claimed in Claim 14 wherein said support member is demountably positionable on support structure for locating the support member at a fixed location relative to a ground surface over which mobile articles are movable, the other coupling means of each said coupling device being secured to a respective one of said mobile articles.

17. The combination claimed in Claim 16 further including a transportable structure for receiving said support member when demounted whereby, by moving said transportable structure and received support member, mobile articles secured to the support member by said releasable coupling devices can be moved over said ground surface together.

18. The combination claimed in Claim 14 wherein said support member is formed on a transportable member movable over a ground surface.