Abstract:
A liquid flow restrictor in the supply line of an eductor or other dilution or dispensing device has a rotatably mounted disc with opposite faces and a plurality of apertures or holes, which provide different flow restrictions between the faces, and a pair of flow conduits sealingly engaging against the faces, whereby on rotation of the member the zones are selectively brought into communication with the conduits to provide a desired flow restriction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     None 
     FIELD OF THE INVENTION 
     The invention relates to the field of fluid dispensers, in particular manually operated dispensers of a type which include a reservoir and which for example dispense single shots of fluid from an outlet and into a container to be filled. 
     BACKGROUND OF THE INVENTION 
     In many organisations, for example in industry, in large kitchens and in large hotels where many rooms need to be cleaned regularly, small containers, such as easily portable bottles, are frequently refilled with cleaning and sanitising liquids from bulk containers held at a filling station. The dispenser is typically of the type described in EP 0868137. This describes a manually operated dispenser for dispensing measured single shots of fluid from a reservoir into a container positioned beneath the outlet. The containers being filled are typically labelled or coloured, in order to indicate the liquid which they should contain. There are obvious risks of errors here, that a liquid might be filled into a container for which it was not intended, particularly when many people frequently visit a filling station. Simple colour coding systems, whilst helpful, do not remove the possibility of human error. 
     Attempts have been made to overcome this problem by electronic automated filling systems, but these tend to be very complex, involving for example the reading of bar code labels. Such systems are expensive, they require expert set-up and maintenance and are prone to the occurrence of faults. 
     Document US-B1-6,279,836 describes a fluid dispenser in which the insertion of containers for which the dispenser is not intended is prevented by providing inwardly facing projections on the sides of a container receiving portion of the dispenser which engage complementary grooves in the side of the container as it is inserted into the dispenser for filling. Once the container is inserted to its full horizontal depth, it can be raised whereby the projections follow a “T” arm of the groove in the container side. Raising the container brings the container mouth to a position where it surrounds a filling nozzle, and at the same time the container mouth raises a slider which operates the fluid dispenser main valve. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a mechanically operated dispensing apparatus which is simple, dependable and low-cost, and which permits the dispensing of a specific liquid into a specific purpose-made container, whilst, at the same time, minimising the risk of inadvertent filling of containers intended for other liquids and the risk of spillages. 
     According to the present invention, there is provided a dispensing apparatus for delivering fluid to a container, the apparatus comprising: 
     container holding means for receiving in use a container having a fill port and a container identifier key, the container holding means including mechanical keying means arranged to permit a container with a predetermined identifier key to be completely inserted to a refill position in the container holding means, 
     a dispensing outlet for delivering fluid to the fill port of a container at the refill position, 
     fluid delivery means for delivering fluid to the dispensing outlet, 
     an actuation member movable from a start position and operatively linked to the fluid delivery means to cause the fluid delivery means to deliver fluid in response to movement of the actuation member from the start position, 
     a dispensing lock having a first position in which it blocks movement of the actuation member from the start position, and a second position in which it permits movement of the actuation member, 
     release means for releasing the dispensing lock including a movable release member which is moved by a container, during its insertion into the refill position in the container retention means, so as to release the dispensing lock by bringing the dispensing lock to the second position, thus enabling fluid to be delivered. 
     The mechanical keying means preferably comprises one or more keying elements of predetermined shape and configuration, said elements being arranged for cooperation with a predetermined container identifier key having one of more keying elements of corresponding shape and configuration, thereby permitting the complete insertion of the container into the container holding means. 
     In this manner it is possible for the container holding means to allow the full and complete insertion of a certain type of container whilst blocking the insertion of other types, i.e. types which do not carry a specific identifier key. The specific container identifier key of a container intended for complete insertion into the container holding means is typically configured to cooperate in a mating manner with the mechanical keying means of the container holding means. Preferably either the mechanical keying means or the container identifier key includes an array of projections or an array of recesses or a combination of the two for cooperation with a corresponding mating array of projections and/or recesses on the other of these two parts. 
     Preferably the movable release member is arranged to be moved by a container during substantially complete insertion of the container into the container holding means. Preferably, the movable release member is located at an end region of a slot of the container holding means, the slot serving to receive a correctly inserted container, so that the container makes contact with and moves the movable release member at the end of its travel in the slot, during insertion. 
     Preferably the movable release means is a pivotally mounted bar member having a first portion arranged for interaction with an inserted container and a second portion arranged for interaction with the dispensing lock means. The movable release member is preferably arranged to move in a plane which is substantially in line with the insertion path of the container as it is inserted into the container holding means and in the case where the holding means takes the form of a slot, then substantially in line with the centre-line of the slot. 
     The movable release member is preferably mounted on a portion of the dispensing apparatus and is furthermore preferably located, in use, above a region in close proximity to the furthest point of travel into the apparatus of a fully inserted container. 
     The first portion of the movable release member is preferably located in close proximity to the container holding means. The first portion of the movable release member is more preferably located in close proximity to the furthest point of travel into the container holding means of a fully inserted container. 
     The movable release member has preferably an elongate shape and is more preferably substantially “T” shaped i.e. substantially in one plane. The movable release member is preferably mounted so as to extend substantially entirely in a vertical or near vertical plane. The first portion and the second portion are preferably at substantially opposite ends of the movable release member and the pivot which supports the movable release member is preferably positioned between the two ends. The movable release member preferably pivots about a substantially horizontal axis, the axis being preferably substantially perpendicular to the insertion direction of the container. 
     The dispensing lock means preferably has one movable locking member, or more preferably two movable locking members, which, in one position act to block movement of the actuation member i.e. plunger and thereby prevent actuation of the piston, and in a second position, permit the actuation member to move in response to an externally applied force. 
     Preferably the, or each of the, movable locking members is a pivotally mounted rocking arm which is capable of rotation between said first and second positions in response to movement of the release means. 
     The fluid delivery means preferably includes a working chamber and a piston means, the working chamber being selectively communicable with a fluid supply i.e. tank or reservoir within the apparatus and the dispensing passage. The working chamber can be of any convenient shape but will typically take the form of a cylinder or a cylinder of circular cross-section i.e. for cooperation with a circular piston. 
     Typically either the piston means or the boundary wall of the working chamber i.e. the cylinder, will be movable relative to the dispensing apparatus, whilst the other will be fixed. Either one or the other is then preferably actuable in response to movement of the actuation member to pressurise fluid in the working chamber for delivery to the dispensing passage. 
     The actuation member is preferably at least partially exposed to the exterior of the apparatus. The actuation member is preferably a plunger which is arranged for movement independently of the piston (or working chamber/cylinder, cylinder wall, whichever is movable), said actuation member being movable in response to an externally applied force i.e. when depressed by an operator, to move the piston and thereby pressurise the fluid in the working chamber and deliver fluid from the dispensing passage. 
     The actuation member may take other forms such as a button or lever to which force can be applied by an operator. 
     It is envisaged that the present invention will be used with any suitable shape, size and type of container with a port suitable for refilling the container and a container identifier key suitable for use with the present dispensing apparatus. It is also envisaged that the containers for use with the dispensing apparatus of the present invention may also include aspects of other recognition systems such as colour, shape etc. to visually assist the operator before he makes an attempt at inserting a container into the dispensing apparatus. 
    
    
     
       INTRODUCTION OF THE DRAWINGS 
       An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, in which:— 
         FIG. 1  is a front view of the dispensing apparatus embodying the invention, in which a container has been inserted. 
         FIG. 2  is a side view of the dispensing apparatus of  FIG. 1  with a container which is not fully inserted. 
         FIG. 3  is a side view of the dispensing apparatus of  FIG. 1 , with a fully inserted container. 
         FIG. 4  is a top view of the apparatus of  FIG. 1  in horizontal section and in its “stand-by” position. 
         FIG. 5  is a top view of the apparatus of  FIG. 1  when a container is fully inserted. 
         FIG. 6  is a top view of the apparatus of  FIG. 1  after the plunger has been pushed in. 
         FIG. 7  is a top view of the apparatus of  FIG. 1  where the plunger has retreated to its starting position and the cylinder is beginning to refill. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The fluid dispensing apparatus shown in  FIGS. 1 to 7  has a fixed frame structure in the form of an enclosed housing  30 ,  34  and a bottle retainer  2  including a back plate  6  which is either joined or unitary with the housing  30 ,  34 . The housing  30 ,  34  and bottle retainer  2  are shown mounted on a vertical wall  40 , e.g. a building wall. The housing generally has a top box  34  which carries a removable or refillable reservoir (not shown) of fluid to be dispensed, and a lower housing portion  30  in which the dispensing mechanism is located. The lower housing portion  30  is located above a dispensing outlet  18 , through which fluid being dispensed is delivered into the filling port  13  of a container located beneath the outlet  18 . 
     The reservoir of fluid to be dispensed (not shown) is arranged within the top box  34  and passage  33  is arranged between the reservoir and the dispensing outlet  18 . Suitable piping arrangements, including valves, are shown in EP-A-868137. A pump comprising a cylinder  26  and piston  25 , which together define a working chamber  29 , is connected through a common inlet/outlet passage  32  to passage  33 . The piston  25  is slidably arranged within the cylinder  26  where it is capable of reciprocal movement. The piston  25  is attached to a piston stem  24  of a piston sleeve  23 . The piston sleeve  23  slidably surrounds the cylinder  26 . 
     The piston stem  24  is an axial projection attached to the centre of a radially extending flange  23   a  within the piston sleeve  23 . The flange  23   a  is located towards the outer end of sleeve  23  and is attached to the inner wall of the sleeve. 
     A plunger  20  is slidably arranged on the outside of the piston sleeve  23 , towards the outer end thereof. The piston sleeve  23 , with its piston stem  24 , are slidable relative to the plunger  20 . 
     As can be seen in  FIGS. 4 to 7 , the plunger  20  is a cup-shaped component with a cylindrical portion, an end cap  20   a , a bearing surface  20   b  at one end and a flange  22  at its other end. The plunger  20  is slidingly mounted on the outside of piston sleeve  23  and is also arranged to slide within an aperture  30   d  in the front wall of the housing  30 . The plunger flange  22 , being of greater diameter than the aperture  30   d  ensures that the plunger cannot be removed from the front wall of the housing and therefore serves to define an outwards end position of the plunger  20  when this is not depressed into the dispensing apparatus (e.g. as in  FIG. 4 ). The plunger flange  22  is also provided with indent portions  22   b ,  22   b ′, at its radially outward edge, which face inwardly i.e. in the general direction of the working chamber  29  of the apparatus. The flange indent portions  22   b ,  22   b ′ extend to the outer edge of the flange are arranged to receive the inclined nose portions  10   a  of respective rocking arms  9 ,  9 ′ described below. 
     The bottle retainer  2  consists of the two forwardly projecting arms  2 ,  2 ′ which are attached to the back plate  6 , forming a slot-like opening  19  into which a bottle  1  can be inserted. The arms  2 ,  2 ′ carry rails  21 ,  21 ′ which are arranged to cooperate with corresponding slots  1   a ,  1   b  in the bottle  1 . 
     The bottle retainer  2  carries mechanical keying means in the forms of an arrangement of projections at the base of slot-like opening  19  of retainer  2  for cooperation with an appropriately keyed bottle, as for example described in greater detail in the European patent application EP0675073. A bottle which is intended to be insertable into the retainer  2  carries recesses in positions corresponding to the projections at the bottom of opening  19 , whereon other bottles cannot be fully inserted into the base of opening  19 , which means they cannot reach the refill position. The recesses on the bottle therefore serve as the bottle identifier key and whether or not this matches the projections at the base of opening  19  determines whether a particular bottle type can be fully inserted into a particular dispenser. 
     Alternatively, the rails  21 ,  21 ′ can each carry a shaped formation which serves as the mechanical keying means of the retainer  2 . In this case a bottle  1  which is intended to be insertable into the retainer  2  carries at the bottom of the slots  1   a ,  1   b  formations intended for mating cooperation with the mechanical keying formations of arms  2 ,  2 ′. The mechanical keying formations can be designed to allow the insertion into the retainer of a particular type of bottle which carries a corresponding mating container identifier key and to block the insertion of other bottles which do not carry the appropriate identifier key. 
       FIG. 2  shows a bottle retainer  2  receiving a bottle which includes the specific identifier key which enable it to cooperate with the mechanical keying formation of the retainer  2  and become fully inserted in the retainer  2  as illustrated in  FIG. 3 . 
     As can be seen from  FIGS. 2 and 3 , the bottle  1  is inserted into the dispensing apparatus in a generally horizontal direction as it moves along the guide rails  21 ,  21 ′. As illustrated in  FIG. 3 , the bottle  1  comes to rest in its final insertion position with its filling port  13  directly beneath the dispensing outlet  18 . The retainer  2 , also includes latches, pips or beads (not shown) which help to secure the bottle in its fully inserted final position of travel with the dispensing apparatus by engaging with corresponding pips or beads in slots  1   a ,  1   b  on the bottle. Alternatively, a pair of lugs on the bottle may drop down into respective grooves on rails  21 ,  21 ′ as shown in EP0675073. 
     A substantially “T” shaped movable release member  3  is illustrated in  FIG. 1  and in two operating positions in  FIGS. 2 and 3  respectively. As can be seen from the figures, the movable release member is mounted on a pivot  5  and extends partially into the slot  19  between the arms  2 ,  2 ′. The movable release member  3  has a first contact point  4  at its lower end which is located, in use, in the insertion path of the bottle  1 . As the bottle reaches nearly to its fully inserted position, it makes contact with the contact point  4  of the movable release member  3 . As insertion continues, further movement of the bottle displaces the contact point  4  thereby deflecting the release member  3  from its rest position, which is inclined to the vertical as illustrated in  FIG. 2 , to a releasing position, where it is in a substantially vertical orientation, as illustrated in  FIG. 3 . 
     As can be seen in  FIGS. 2 and 3 , the pivoting axis of pivot  5  is substantially horizontal and is substantially perpendicular to the insertion direction of the bottle  1 . Moreover, the lower portion of  3   a  of the release member  3  is substantially aligned with the centre line of the slot  19 . This means that the front portion of a bottle  1  having a rounded cross section, will confront the contact point  4 , as illustrated in the Figures. This enables the presence of a fully and correctly inserted bottle to be detected by the release member  3  in a simple and reliable manner. The shape of the release member  3  and its position towards the centre of the dispensing apparatus makes it more difficult for an operator who has not inserted the correct bottle for this retainer  2  to depress and therefore activate the release member. Further guard means (not shown) e.g. in the form of walls on either side of release member  3  are also provided to hinder access by an operator to the release member  3  and therefore make it more difficult to operate the dispenser without the correctly keyed bottle having been fully inserted. 
     The horizontal upper portion  3   b  of the member  3  has two end portions  7 ,  7 ′ between which the approximately vertical lower portion  3   a  is attached to form the “T” shape configuration. As can be seen in  FIGS. 4 to 7 , end portions  7 ,  7 ′ project substantially laterally from the upper portion  3   b  and into apertures  30   b  in the rear of the lower housing portion  30 . The end portions  7 ,  7 ′ serve as contact points which contact respective recesses (not shown) on heels  15 ,  15 ′ at the end of two respective rocking arms  9 ,  9 ′. The rocking arms  9 ,  9 ′ are disposed substantially horizontally, one at either side of the plunger/piston/ cylinder assembly, and each has a latch  10 ,  10 ′ which projects inwardly (towards the plunger) at an inclined nose portion  10   a  thereof. The nose portion has the end surface  10   d  of the latch  10 ,  10 ′ to one side and facing outwards (relative to the centre of the dispenser) and to the other side an inward facing surface  10   b  which is inclined to the axis of its arm  9 . The end surfaces  10   d  of latches  10 ,  10 ′ are oblique relative to the longitudinal direction of the arms  9 ,  9 ′ and therefore also to the rear faces of the heels  15 ,  15 ′ and are furthermore also provided with flat portions  10   c  which extend substantially perpendicular to the longitudinal direction of the arms  9 ,  9 ′ and which are arranged for engagement with latch plate bearing surfaces  16   a  to be described below. The heels  15 ,  15 ′ of the rocking arms  9 ,  9 ′ are arranged to pivot on pivots  30   a  of the housing  30  so as to be capable of moving in a substantially horizontal plane. Pivots  30   a  are in the form of elongated ridges  30   a , extending substantially vertically, for co-operation with respective elongate indentations  15   b  of heels  15 ,  15 ′. 
     As can be seen from the figures, the pivots  30   a  of the heels  15 ,  15 ′ are not aligned with the centres of the heels  15 ,  15 ′ but are offset to one side, i.e. inwardly. With no bottle inserted, then under the influence of compression springs  14 ,  14 ′ which are arranged to act on the heels  15 , the rocking arms  9 ,  9 ′ will adopt the rest position illustrated in  FIG. 4 , with the rocking arms  9 ,  9 ′ slightly outwardly inclined. 
     Also illustrated is a substantially annular latch plate  16 , extending substantially perpendicular to the plunger/ piston/cylinder axis, and having apertures  16   b , the bearing surfaces  16   a  against which the compression spring  14 ,  14 ′ acts and a rim  16   c  which maintains the position of the springs  14 ,  14 ′ on the latch plate. The latch plate  16  is mounted against shoulder  23   b  on the outer surface of piston sleeve  23 . The springs  14 ,  14 ′ are normally under compression so as to tend to push the latch plate  16  away from the associated heels  15 ,  15 ′. The plunger  20  acts on the piston sleeve  23  and latch plate  16  so that, when the plunger  20  is pushed into the apparatus, it moves the piston sleeve  23 /latch plate  16  towards the heels  15 ,  15 ′ over the outside of cylinder  26 . 
     The apertures  16   b  are large enough to receive the end portions of the latches  10 ,  10 ′ of the rocking arms  9 ,  9 ′. This permits the latch plate when moved by the plunger in line with the plunger/piston/ cylinder axis to pass over the rocking arms  9 ,  9 ′, when the latches  10 ,  10 ′ of the rocking arms are in alignment with latch plate apertures  16   b . The plunger  20  is arranged to act, through the plunger flange face  22   a , against the latch plate  16  (as shown in  FIGS. 4 ,  5 ,  6 ). The apertures  16   b  allow for movement of the piston sleeve  23 /latch plate  16  over the outside of cylinder  26 , said apertures passing over the rocking arms  9 ,  9 ′, as the plunger  20  is depressed. At the inner side of each aperture  16   b , there is an edge  16   d , arranged relative to the rocking arm be in abutment with an inclined nose portion  10   a  of the rocking arm, when the plunger is in the outer position (as in  FIG. 5 ). The edge  16   d  thus acts to hold the inclined nose portion  10   a  of the rocking arm into the position in which it is substantially radially aligned with the outside of the plunger flange  22 , it being understood that the flange  22  extends substantially the same distance outwardly as the edge  16   d  at the inner side of the latch plate aperture  16   b.    
     The springs  14 ,  14 ′ act to push the piston  25  out of the piston cylinder  26  (through latch plate  16 , shoulder  23   b , sleeve  23 , stem  24 ), so as to draw a shot of liquid from the reservoir, through passages  33  and  32 , and into the working chamber  29  bounded by piston  25  and cylinder wall  26 . 
     Between the flange  23   a  of the piston sleeve  23  and a bearing surface  20   b  of the plunger is arranged a plunger compression spring  27  which acts so as to urge the plunger  20  away from the piston sleeve  23  and therefore piston  25 . This spring  27  is, however, weaker than the springs  14 ,  14 ′ so that spring  27  is not able to push the piston  25  against the force of the springs  14 ,  14 ′. 
     The operation of the dispensing apparatus is as follows.  FIG. 4  shows the dispensing apparatus in its “standby” condition in which a bottle  1  to be refilled has not been fully inserted into the dispensing apparatus (e.g. as is shown in  FIG. 2 ). In this condition, the flat portions  10   c  at the end of rocking arms  9 ,  9 ′ act on the bearing surface  16   a  of the latch plate  16  to lock the latch plate in its forward position and hold the plunger flange  22  against the front wall of the housing  30 . Thus, in this condition, it is not possible for an operator to depress the plunger  20 . 
       FIG. 5  illustrates the dispensing apparatus in its “ready to dose” condition. Here, as illustrated in  FIG. 3 , a bottle  1  has been fully and correctly inserted in cooperation with the mechanical key of the retainer  2  and into its final position in the retainer. The moveable release member  3  has been pushed into a second position (as in  FIG. 3 ). The second position can also be seen in  FIG. 5  where the top portion  3   b  of the release member  3  has moved closer to the rear wall of the housing  30 , pushing end portions  7 ,  7   a  of the release member through respective apertures  30   b ,  30   b ′ in the rear wall and into respective recesses of heels  15 ,  15 ′. The end portions  7 ,  7 ′ act on respective outer sides of heels  15 ,  15 ′ so that the pivoting axis of the heels changes from pivots  30   a  to the point of contact between end portions  7 ,  7 ′ and heels  15 ,  15 ′. The force of springs  14 ,  14 ′ acting on the new offset pivoting axis  7 ,  7 ′ of heels  15 ,  15 ′ causes the rocking arms  9 ,  9 ′ to move inwardly compared to the standby condition, as shown in  FIG. 5 . In this condition, the flat portions  10   c , at the end of the rocking arms, have disengaged the latch plate  16  and the latches  10 ,  10 ′ at the end of rocking arms are substantially aligned with the apertures  16   b  in the latch plate. Consequently, in this condition, the plunger can be depressed by an operator into the dispensing apparatus whereby the inclined nose portions  10   a  of the latches  10 ,  10 ′ are free to slide across the inner edge  16   d  of the latch plate apertures and similarly across the outer edge of plunger flange  22 , as the plunger is depressed. Inclined nose portions  10   a  are formed in such a manner, i.e. with a rounded tip or with a tip inclined to the axis of the rocking arms, such that they do not engage the flange indent portions  22   b ,  22   b ′ when the plunger flange  22  and latch plate  16  are in abutment (as shown in  FIG. 5 ). In other words, as the plunger is depressed, the nose portions  10   a  of latches  10  cannot travel sufficiently radially inwards, into the indent portions  22   b ,  22   b ′, to engage the bottom of the indent portions and block movement of the plunger. 
     Incidentally, a readiness indicator  31  mounted on one of the latch plate  16 , protrudes forwardly through an aperture  30   c  in the front wall of the housing, so that an operator can see that the dispenser is ready to dispense. 
     When the operator depresses the plunger  20 , the plunger pushes the piston sleeve  23 , the latch plate  16 , the piston stem  24  and piston  25  into the dispenser, thus delivering the contents of the working chamber  29  through the inlet/outlet passage  32  to the dispenser outlet  18 . 
       FIG. 6  shows the maximum depression of the plunger into the dispenser, where the piston  25  has reached the back wall  26  of the cylinder, thus having dispensed the contents of the working chamber. The action of depressing the plunger takes place against the force produced by the springs  14 ,  14 ′ and as soon as the operator stops applying a force to the plunger  20 , i.e. after it has reached its final position of travel, these springs  14 ,  14 ′ start to move the piston  25  away from the cylinder back wall by a force applied through latch plate  16  to shoulder  23   b  on the outer surface of the piston sleeve  23 . In this way, the spring force of springs  14  is transferred through piston sleeve  23  and piston stem  24  to the piston  25  and as the piston moves back from its end position it draws in liquid through the inlet/outlet passage  32  from the fluid supply reservoir and into the working chamber  29 . 
     At the same time, whilst the working chamber  29  begins to fill when the operator is no longer depressing plunger  20 , the plunger quickly moves back out of the dispenser under the force produced by plunger spring  27 . Whilst spring  27  is weaker than the main springs  14 , it is sufficiently strong to relatively quickly move the plunger away from the end of piston sleeve  23 . This contrasts with the relatively slower movement of the piston sleeve out of the dispenser under the force of main springs  14  as these springs are working to refill the working chamber  29 . As the plunger  20  reaches its final outward position of travel under the influence of plunger spring  27 , then the plunger flange  22  will make contact with and pass over latches  10 ,  10 ′, nudging them slightly outwards in the process. The fully outward position of the plunger is illustrated in  FIG. 7  and as can be seen, the latches  10 , after being temporarily displaced outwardly as the flange  22  passed by, have moved back inwardly along indent portions  22   b ,  22   b ′ in the end surface  22   a  of the flange, i.e. further radially inwardly than is possible when the latch plate  16  is abutting flange  22 . 
     As the indent portions  22   b ,  22   b ′ only extend a certain distance inwards from the outer edge of the flange  22 , they therefore include an end wall. As the latches  10 ,  10 ′ move back inwards, once the flange  22  has passed, then they move down the indent portions  22   b ,  22   b ′ until stopped from travelling further inwards by the position adopted by heels  15 . In this condition, which is illustrated in  FIG. 7 , the force from the springs  14 ,  14 ′ on heels  15 ,  15 ′ pivoting on ends  7 ,  7 ′ of release member  3  tend to move the rocking arms  9  and therefore latches  10  inwards. Further movement inwards is opposed by ridges  30   a  abutting the rear wall of heels  15 ,  15 ′ (ridges  30   a  are not acting as pivots in this condition). 
     From the condition illustrated in  FIG. 7 , where the plunger is in its fully outward position and the piston  25 , piston sleeve  23  and latch plate  16  are slowly moving as the working chamber  29  is filling, the latch plate  16  approaches the end face  22   a  of the plunger flange  22 . As the latch plate  16  reaches the flange  22 , it firstly comes into contact with the inward facing portions  10   b  of respective latches  10 ,  10 ′, nudging the latches  10 ,  10 ′ outwardly so that nose portions  10   a  no longer engage indent portions  22   b ,  22   b ′ and the rocking arms  9 ,  9 ′ assume again the position generally illustrated in  FIG. 5 . Here the nose portions  10   a  of latches  10 ,  10 ′ rest at the position of the inner edge  16   d  of apertures  16   b.    
     If the bottle  1  is left in its fully inserted position, then it would be possible for the operator to depress, once again, the plunger and dispense another dose of fluid into the bottle. However, if the bottle  1  is moved out of the dispenser, i.e. backwards from its fully inserted position, then the condition of the dispenser will change from that which is illustrated in  FIG. 3  to a condition such as the one illustrated in  FIG. 2 . When this happens, then the end portions  7 ,  7 ′ of the release member no longer act as pivots for heels  15 ,  15 ′ and with the heels pivoting on ridges  30   a , the rocking arms  9 ,  9 ′ and therefore latches  10 ,  10 ′ then move outwardly under the influence of springs  14 ,  14 ′. Once this happens, the flat portions  10   c  of the rocking arms move out of the latch plate apertures  16   b  to a position where they oppose or latch against the bearing surfaces  16   a  i.e. the inner facing surface, of the latch plate  16  to assume once again the condition generally illustrated in  FIG. 4 . The dispenser is therefore back in its standby condition and the plunger cannot be depressed until a bottle i.e. a bottle carrying the correct identifier key for this dispenser, is once again fully inserted into the retainer  2 .