The present invention relates to an apparatus for varying the quantity of contents in a receptacle and in particular, but not exclusively, the invention relates to apparatus for dispensing the contents of a receptacle.

The dispensing of the contents of a receptacle is commonly required in industrial and medical processes and the quantity and speed with which the contents have to be dispensed generally dictates the type of dispensing system employed. For example, where large quantities of the contents, for example fluid, are to be dispensed, and economic factors are a relatively minor consideration, it is common to find some form of electrically driven pump being used to dispense the fluid from a reservoir. For much smaller quantities, the well known piston syringe type device has found common use particularly for medical purposes.

In many situations, driven-pump dispensing apparatus is not suitable having regard to the quantity of the receptacle contents to be dispensed, and also due to other factors such as the cost of using and maintaining the apparatus.

The piston syringe type devices referred to above are also disadvantageous in that the user has to supply the driving force to dispense the contents in addition to controlling the accuracy with which the contents are to be dispensed. This type of known apparatus is also restricted to use which requires a small quantity of fluid to be dispensed quickly.

One form of dispensing apparatus that does not require

the user to apply a driving force and so leaves its user free to concentrate on the accuracy and amount of the contents dispensed, and to leave the apparatus "free- running" once initially set up, comprises, a gravity drip- feed bag. Such apparatus is widely used in the medical field for the intravenous administration of fluids to a patient. However, it is restricted in that the pressure available for dispensing the fluid is limited to that provided by gravity. Also, the apparatus is awkward and cumbersome in that a separate stand is generally necessary to support the bag above the point at which the fluid is introduced into the patient's body.

It would therefore be advantageous to provide dispensing apparatus for a receptacle's contents which is simple and inexpensive and allows for the dispensing of fluid, as required, without any driving force needing to be applied by the user.

The present invention seeks to provide simple, and inexpensive apparatus for varying the quantity of contents in a receptacle.

According to the present invention there is provided apparatus for varying the quantity of contents in a receptacle having an opening, said apparatus comprising deformation means for deforming said receptacle to thereby cause a change in the quantity of contents in said receptacle, wherein said deformation means has a stable state and an unstable state and when in said unstable state seeks to change to said stable state and thereby deform said receptacle so as to cause said change in the quantity of said contents.

One way of providing such a deformation means is by way of a resilient member which is resiliently deformable

between an at least partially coiled state and an at least partially uncoiled state, said resilient member being operative to deform said receptacle during movement between said states in accordance with its resilience.

The invention can advantageously provide for an inexpensive and simple means for discharging the contents of a receptacle. The apparatus of the invention is also reliable and can allow for the discharge of the contents at a predetermined uniform rate.

Preferably, the resilient member is arranged to have a coil portion at one end thereof for rolling or unrolling as required in accordance with its resilience.

In one series of embodiments of the present invention, the resilient member is arranged to deform the receptacle, so as to dispense contents therefrom. As such, the resilience of the member causes it to move from a first, coiled state, to a second, more coiled state. In this manner, the receptacle can have similar longitudinal dimensions to that of the resilient member. One end of the receptacle is then coiled within a coiled portion of the resilient member and its contents are thereby forced into a region of the receptacle which is, at that time, outside of the coil. In such an instance, the coiled portion of the resilient member serves to act as retaining means for the receptacle.

Of course, the dimensions of the receptacle need not mirror those of the resilient member and the receptacle. Also, the receptacle can advantageously be formed with a thinner "tail" portion which can be readily located in the coil portion formed at one end of the resilient member.

Advantageously, attachment means can be provided for

securing the receptacle along at least part of the length of the resilient member. Additionally, flexible coupling means can be provided for connecting said receptacle to said outlet means.

In one embodiment, discharge control means is provided at the end of the resilient member remote from the end at which the coil is first formed and, with the receptacle attached to the resilient member for operation, the opening of the receptacle can be located in the region of the flow control element whereby the passage of the receptacle contents can be controlled as required. In particular, the discharge control means can have a plurality of different size conduits passing therethrough, which provide for different respective discharge rates.

The discharge control means may also comprise brake or escapement means for controlling the speed at which the member rolls or unrolls when coiling or uncoiling as required.

Advantageously, means can be provided for forming the inner diameter of said coil portion at a value greater than the natural resting inner diameter of the coil. This can advantageously assist in seeking to expel substantially all of the contents from said receptacle.

Once the dispensing of the receptacle contents commences according to such an embodiment, the resilient member coils at its end remote from the discharge control means and the coil member therefore effectively rolls-up from one end towards another. During this rolling of the coil, the receptacle is deformed by the coiling portion and so advantageously maintains pressure on the contents of the receptacle. Thus, with an appropriate resilient member, having regard to the contents of the receptacle, a

continuous steady flow of the contents out of the receptacle can be obtained.

Advantageously, the resiliently deformable member comprises a coil spring member which can be fully unrolled to receive the receptacle. Thus, in accordance with its resilience, the unrolled spring member seeks to roll-up to its fully coiled state.

Alternatively, the resilient member can be arranged to uncoil in accordance with its resilience so that the receptacle is deformed as the resilient member moves from a first coiled state to a second, less coiled, state. The resilient member may then comprise a flat spring member which is rolled-up so as to uncoil as required in accordance with its resilience. According to this alternative, the apparatus includes a surface against which the uncoiling resilient member is arranged to urge the receptacle. In particular, the surface is provided by pinch means arranged to engage, and move with, the uncoiling portion of the resilient member. Alternatively, the surface can be provided by an elongate support surface which remains stationary relative to the travel of the coiling portion of the resilient member. The support surface may comprise an inner surface of housing means for the apparatus.

Pinch means may also be arranged to be engaged with the coiling portion of a resilient member for movement therewith as it rolls into a fully coiled state in accordance with its resilience.

Irrespective of whether the resilient member is arranged to coil or uncoil in accordance with its resilience, means can be provided so as to compensate for the change in the thickness of the coiled portion that

results from the coiling or uncoiling. Such means may comprise resilient mounting means for the above-mentioned pinch means or may comprise tracking means formed in or with housing means for controlling and determining the path of the coiling or uncoiling portion of the resilient member. As such, the coiling or uncoiling portion of the resilient member does not cause a snag or a decrease in its effectiveness as regards the deformation of the receptacle.

Further, said pinch means may comprise a pinch roller. The pinch roller can be resiliently mounted with respect to the coiling or uncoiling portion of the resilient member.

The resilient member may also be arranged to provide retaining support for the receptacle prior to it being coiled and, as such, the resilient member may comprise a flexible band as described in published United Kingdom patent application GB 2 229 318 A, the contents of which are incorporated herein by reference. The use of such a resilient member as described in that published application is advantageous in view of the stability of the member, particularly in its uncoiled form.

Preferably, said deformation means is arranged to apply a non-constant force to said receptacle and, in particular, one that increases as the deformation of said receptacle increases. Any increase in the resistance presented by said receptacle to a change in state of said deformation means can thereby be advantageously compensated for to maintain any required rate of change of the amount of contents in the receptacle.

In another embodiment of the present invention, the resilient member comprises a member which tends to uncoil in accordance with its resilience and whereby such uncoiling is arranged to allow for the increase in volume

of a receptacle arranged therewith. As such, the unrolling coiled member causes a decrease in pressure in the receptacle and can thereby be operative to draw the required material into the receptacle. Resilient means can be provided within the receptacle so as to assist its expansion as the coil unrolls.

It can be seen that the invention advantageously provides either for simple and inexpensive dispensing apparatus which can dispense a receptacle's contents steadily and continuously if required, or a receptacle- filling apparatus in which a receptacle can be filled or partially filled, as required, in a continuous and steady manner.

Preferably, the coil is arranged to form about an axis which is perpendicular to the longitudinal extent of the resilient member.

It should be appreciated of course that the resilient member may also comprise a member arranged to move between two coiled states in accordance with its resilience.

Also, means may be provided for indicating the quantity of the contents dispersed or still to be dispensed, or the volume still available to receive more of the appropriate material. Such means may comprise markings on the receptacle, or on the resilient member. Alternatively, such indication can be provided by the position of the coiled portion of the resilient member relative to some other part of the resilient member or the housing.

In providing for means for introducing contents into the receptacle, the apparatus can include means for expanding said receptacle so as to draw contents therein.

The receptacle can be expanded by selectively operable resilient means that, if required, can be similar in form to said deformation means, or said receptacle can be located in housing means from which air can be evacuated.

From the above it can be seen that simply by means of a constant force resilient member, ie. a single element, it is possible to provided for the dispensing of a receptacle's contents at a constant rate.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a side elevational view of apparatus according to one embodiment of the present invention;

Figure 2 is a cross-section through the line II-II of Figure 1;

Figure 3 is a side elevational view of apparatus according to another embodiment of the present invention;

Figure 4 is a cross-section through the line IV-IV of Figure 3;

Figure 5 is a side elevational view of apparatus according to a further embodiment of the present invention;

Figure 6 is a cross-section through the line VI-VI of Figure 5;

Figure 7 is a perspective view of one form of resilient member for use with apparatus embodying the present invention;

Figure 8 is a perspective view of another form of resilient member for use in apparatus embodying the present invention;

Figure 9 is a perspective view of apparatus according to yet another embodiment of the present invention;

Figure 10 is a perspective view of apparatus according to yet a further embodiment of the present invention,-

Figure 11 is a side elevational view of apparatus according to a still further embodiment of the present invention;

Figure 12 is a side elevational view of the apparatus of Fig. 1 but with further modifications;

Figure 13 is a plan view of a resilient member and receptacle for providing further advantageous features of the present invention,-

Figure 14 is a side elevational view of apparatus provided for unrolling a coiled resilient member,-

Figures 15a and 15b are cross-sectional views through an embodiment of the present invention particularly arranged for the filling of a receptacle;

Figures. 16a and 16b are plan and sectional views respectively of one form of material for forming the resilient member of the present invention,-

Figures 17a and 17b are plan and sectional views respectively of another material for forming the resilient member of the present invention,- and

Figures 18a and 18b show part plan and part elevational views respectively of still another embodiment of the present invention.

Figure 1 shows dispensing apparatus 10 according to one embodiment of the present invention for dispensing fluid contained in a flexible receptacle. In the example, the receptacle comprises an elongate bag 12, but may of course comprise any suitably deformable receptacle. The dispensing apparatus 10 includes an elongate resilient member, for example a metal spring member 14 which is resiliently deformable so as to be rolled from a completely coiled state to an uncoiled state. For example, the spring member 14 is first deformed, ie. unrolled, to an uncoiled state and then released and its resilience causes it to return, ie. roll-up, to its coiled state by coiling from one end towards the other. The spring member 14 in Figure 1 is shown between these two states during its coiling from one end and thus has a coiled portion 20 which is in the process of rolling in the direction of arrow A towards an, as yet, uncoiled end portion 16.

In order to prepare the apparatus of Figure 1 for operation, the spring member 14 is uncoiled so as to allow the elongate bag 12, which is full of fluid, to be laid on top of the spring member 14. The end of the spring member 14 which is to first form the coiled portion 20 is then released and, in accordance with its resilience, seeks to form a coiled portion. The initial success of the spring member 14 in this latter respect depends upon the amount of fluid in the bag. Thus, if the bag 12 does not have any fluid at an end region 24 which overlays the portion 20 of the spring member 14 first forming the coil, or indeed if the bag is provided with a tail portion which is arranged to receive no, only a small amount of the fluid, then the coiled portion 20 can readily be formed at one end of the

spring member 14. As illustrated in Figure 1, the coiled portion can be readily formed of alternate layers of the spring member 14 and bag 24.

The apparatus of Figure 1 also includes a fluid control valve 18 to which the uncoiled end 16 of the spring member 14 is attached and through which a neck portion 22 of the bag 12 passes. The neck portion 22 that extends downstream of the valve 18 can be preformed to provide an opening for the discharge of fluid from the bag 12 or, alternatively, the neck 22 can be provided sealed so as to be cut open when required. In any case, the valve 18 comprises standard known valve means for initiating, controlling and preventing flow of fluid from a receptacle.

With the valve 18 closed, it can be seen from Figure 1 that the coiling portion 20 of the spring member 14 seeks to deform the bag 12 since the coiling portion 20 favours travel in the direction of arrow A and this exerts pressure on the contents in a, as yet uncoiled, portion 26 of the bag 12 which contains fluid to be dispensed. Further coiling of the spring member 14 by the travel of the coiled portion 20 of the spring member 14 in the direction of arrow A is prevented when the pressure of the remaining fluid in the portion 26 is sufficient to prevent further deformation of the bag 12. Thus, the dispensing apparatus 10 is held in equilibrium and will remain in such a state until such time as the valve 18 is opened. At such an instance, the pressure exerted by the coiling portion 20 of the spring member 14 on the portion 26 of the bag 12 causes fluid to be dispensed from the bag 12 via the valve 18 and neck 22. As the fluid is dispensed from the portion 26 of the bag 12, the resistance presented by the portion 26 to the further coiling of the spring member 14 is reduced so that the portion 20 of the spring member 14 resumes its coiling motion in the direction of arrow A. This coiling

motion serves to maintain a pressure on the contents of the as yet uncoiled portion 26 of the bag 12, and this is sufficient to continue the discharge of the fluid via the valve 18 and the neck 22. As can be seen, if the valve 18 remains open so as to allow for complete coiling of the spring member 14 up to the valve 18, substantially all of the fluid in the bag 12 will have been dispensed via the valve 18 and neck 22.

By way of a suitable choice of the spring member 14, for example a constant force spring, a steady uniform flow of fluid can be achieved by merely opening the valve 18. Thus, use of the apparatus so as to achieve a predetermined steady fluid flow merely requires opening of the valve 18 and does not involve the user attending to any further actions to initiate or maintain the flow.

Thus, in a simple form, it can be seen that an embodiment of the present invention can comprise a resiliently deformable coiled spring having its end that is arranged to form the outer end of the coil attached to a flow control valve 18. However, the apparatus of Figure 1 may of course be altered so as to include housing means and also means for assisting the retention of the bag 12 on the spring member 14, such as hook and eye fasteners sold under the trade mark Velcro. If the filled bag 12 provides suitable rigidity, then this will serve to retain the portion of the spring member 14 having the portion 26 thereon in a stable uncoiled state. But, if required in some instances, housing, or other support means, may provide a control function so as to prevent premature or inappropriate coiling of the spring member 14.

Of course the type of spring member 14 used will vary with different applications but a constant force spring member is particularly advantageous for achieving the

uniform discharge of the fluid as discussed above.

Figure 2 is a cross-section through the line II-II in Figure 1 and illustrates further the alternate layers of the spring member 20 and emptied bag 24 forming the coil. Figure 2 also provides an indication of the width of the bag 12 and spring member 14 but, of course, it should be appreciated that these dimensions depend on the required size of the apparatus, and the amount of fluid to be dispensed and thus the size of the bag.

Figure 3 shows another embodiment of the present invention in which a spring member 114 is attached at one end 116 to a valve member 118 and is arranged to receive a bag 112 thereon. The bag 112 has a neck portion 122 which extends through the valve 118 and by which fluid remaining in a portion 126 of the bag 112 is to be dispensed.

The end of the spring member 114 remote from the end 116 forms a coiled portion 120 which includes alternate layers of the spring member 114 and the emptied bag 124. As before, the coiled portion 120 is arranged to travel towards the valve 118 in the direction of arrow 1A to dispense the fluid remaining in the bag portion 126 in a similar manner described above with reference to Figure 1.

The apparatus of Figure 3 includes a cylindrical core member 128 about which the coil portion 120 is formed and which is coaxial with the coiled portion 120. The core member 128 may be chosen to have a diameter that is greater than the inner resting diameter of the coil portion 120. This assists in retaining tension in the coil portion 120 which, in turn, serves to assist the evacuation of the contents of the bag 112.

A spindle 130 extends through the axis of rotation of

the core 128 so at during movement of the coil 120 in the direction of arrow 1A, the core 128 can rotate relative to the spindle 130.

At the ends of the spindle 130, which protrude from the core 128, there is provided respective resilient arm members 132. These arm members 132 are journalled by way of bearings 136 such that the spindle 130 can rotate relative thereto. With reference to both Figure 3 and 4, it can be seen that the arm members 132 are arranged to depend from the spindle 130 and have a pinch roller 130 journalled by way of bearings 138 in the ends of the arm members 132 remote from the ends attached to the spindle 130.

As can be seen, during travel of the coil portion 120 of the spring member 114 in the direction of arrow 1A, the pinch roller 134 is biased into engagement with the underside of the spring member 114 by means of the resilient arms 132. As such, the portion of the bag 112 that is about to enter the coil is pinched between the inner layers of the coil and the roller 134 and this acts to enhance the application of pressure to the contents of the bag 126 and to thereby assist the uniform dispensing of the fluid contents by way of the valve 118 and neck 122. With particular reference to Figure 4 it can be seen that as the diameter of the coiled portion 124 increases during the travel of the coil in the direction of arrow 1A the resilient arm members 132 can compensate for this increase by extending in the radial direction. This serves to maintain the required application of pressure to the contents in the portion 126 of the bag 112 without restricting the rolling of the coil portion 120. Of course, other resilient means could be used to replace the arm members 132 for example helical springs.

The pinch roller 134 is also particularly effective in reducing the amount of fluid that remains in the portion 124 of the bag 112 that becomes layered in the coiled portion 120 of the spring member 114.

In the embodiment illustrated in Figure 5, there is provided a spring member 214, having a first end portion 216 secured in a housing 240 and adjacent valve means 218, and a second end portion 220 having already formed a coil portion. Again, a bag 212 is provided on the spring member 214 and has a first portion 226 containing fluid yet to be discharged and a second portion 224 from which fluid has already been discharged and which now is coiled in the coiled portion 220 of the spring member 214.

With reference to Figures 5 and 6, it can be seen that the apparatus of this embodiment includes a cylindrical core 228 about which the coil portion 220 is formed and which is coaxial with the axis of rotation of the coiled portion 220 when moving in the direction of arrow 2A. As before the core 228 can be chosen to have a diameter greater than the inner resting diameter of the coil portion 220. Each side face of the core member 228 has a circular lug 242 extending therefrom along the axis of rotation of the core member 228. Each side wall of the housing 240 is provided with a slot 244 for co-operating with each respective lug 242 so as to define a path of movement for the core 228 and thus the coil portion 220 as it moves in the direction of arrow 2A. Thus, in use, as the coil portion 220 and core 228 move in the direction of arrow 2A, each lug 242 rotates in the respective slot 244 in which it is located. As can be seen in Figure 5, the slots 244 determine the distance of the lugs 242, and thus the core 228, from the base of the container 240 and so serve to maintain a separation between the surface of the core 228 and the inner surface of the base of the container 240 that

assist the application of the required pressure to the fluid in the portion 226 of the container 214 and also which reduces the amount of fluid remaining in the portion 224 of the bag 214 that has passed into the coil. As can be seen, each track 244 is inclined upwardly in the direction of the valve member 218 and this serves to compensate for the increase in the radius of the coil as it moves in the direction of arrow 2A. Obstruction to the coil portion as it increases in diameter during its movement is also prevented.

It should also be noted that the provision of a core member at the centre of the coil portion assists in preventing the coil binding as it rolls in the direction shown by the arrows.

An alternative to the provision of a core member having a larger diameter than the inner resting diameter of the coil portion is to open out the inner-most coil to an increased diameter and securing the inner-most coil in such a position by bonding it to the adjacent coil layer of the coil portion.

Figure 7 is a perspective view of a resilient member for use in apparatus embodying the present invention and, in particular, shows further detail of the resilient member 14 employed in the apparatus illustrated in Figure 1. The member 14 in Figure 7 is an advantageous alternative to housing or other support means for stabilizing the member during coiling/uncoiling.

The spring member 14 of Figure 7 is shown in a similar state as that in Figure 1, ie. that which arises when the bag 12 is partially drained and having a coil portion 20 and an as yet uncoiled portion 16, for location to the valve member 18. As can be seen, the spring member 14 is

formed such that the portion yet to be coiled exhibits a curvature having a radius of curvature perpendicular to the longitudinal extent thereof, and thus perpendicular to the direction in which the coil portion 20 moves. The formation of the spring member 14 in this manner serves to enhance the stability of the uncoiled portion by allowing only that portion of the spring member 14 which is immediately adjacent to the coil portion 20 to deform so as to become part of the coil. Thus, the curvature of the spring member 14 in a direction perpendicular to that of the movement of the coil portion 20 serves to resist, but not prevent, the formation of a complete coil in accordance with the spring member's resilience.

The formation of spring members 14 having such curvature is described in published United Kingdom patent application GB 2 229 318 A referred to above and, in one form, the curvature can be such so as to provide inclosure or retention means for that portion of the bag that has yet to be coiled. Figure 9 is a perspective view of an example of such an embodiment of the present invention and comprises a spring member 314 having a coil portion 320 and an as yet uncoiled portion 316 extending in a tubular manner so as to enclose at least part of that portion of the bag 312 which is still to be emptied. The bag 312 has a neck 322 which extends from the end of the tubular portion 316. Thus, it can be seen that such an example of apparatus embodying the present invention comprises simple means for providing discharge apparatus having a rigid and self-supporting nozzle portion, for example that formed by the tubular section 316, and which is capable of delivering a steady discharge of the bag's contents. The spring member, or flexible band, can exhibit slight curvature when extended or tight curvature when rolled into a coil. The use of such a spring member removes the need for containment means, guides, rollers etc. since controlled

sequential unrolling of the spring is readily achieved and comprises an inherent quality of such a member. The spring member also exhibits safety features since it is in a curled state about a longitudinal axis or a coiled state about a transverse axis and this limits the dimensions of the region of the member that is in a flat and potentially hazardous state.

Alternatively, it may be desirable to prevent any such curvature of the as yet uncoiled portion and this can be achieved by providing a compound spring member which includes a material layer which is sufficiently isotropic so as to resist the curvature of the uncoiled portion of the spring member. A particular means of achieving this is to bond a layer of fibres to that side of the spring member which is to form a convex surf ce of the coil. The fibres can advantageously extend in a direction perpendicular to the direction of movement of the coil. Figure 8 is a perspective view of an example of such a spring member 214 which, for example, is provided in the apparatus illustrated in Figure 5, and, again is illustrated having a coil portion 220 and an uncoiled portion 216. As above, the spring member 214 has a plurality of parallel fibres 217 extending transversely along its length and each of which extends in a direction perpendicular to the direction of travel of the coil portion 220. In particular, the fibres can be contained in a matrix material which is highly flexible and exhibits little or no viscose damping and so does not act against the rolling or unrolling of the spring coil. However, the fibres, which can be pre- stressed if desired, prevent poison-stress derived curvature of the uncoiled portion 216 of the spring member 214.

Where curvature of the as yet uncoiled portion of the spring member can be permitted, it can be advantageous to

form the actual receptacle itself from such spring members.

An example of such an embodiment is illustrated in Figure 10 and comprises dispensing apparatus 410 formed of a receptacle 412 having upper and lower walls 413, 415 sealed at their edges 417 and each of which comprises a resilient elongate spring member which is resiliently deformable from a substantially completely coiled state to an unrolled, and thus uncoiled, state.

As such, and as can be appreciated from Figure 10, it is an inherent property of the walls of the container 412 itself that the end of the container remote from an outlet hose 422 seeks to form a coil portion. The coil portion increasing in radius as it rolls towards the nozzle portion 419 and as the contents of the receptacle 412 are dispensed via the hose 422. Alternatively, the resilient member could form solely that wall portion of the receptacle which is to become the outer, or convex, surface of the coil portion. In this manner, and with reference to the apparatus of Figure 10, the wall portion 413 of the container 412 could then be formed of any appropriate deformable material which can be sealed at its edges 417 to the resilient member.

As a further alternative of dispensing apparatus, the resilient member could be provided internally of the receptacle itself. Such enclosure of the resilient member also serves to overcome safety hazards that could arise through the use of an exposed spring such as a metal spring.

Devices of the nature outlined above, and with reference to Figures 9 and 10, can prove advantageous in that an additional housing for the apparatus is not required and the spring member can be readily cocked, or

unwound, and the receptacle loaded for use.

Apparatus embodying the present invention is also shown in Figure 11 and, in this case, comprises a resilient member 420 which is arranged to unroll from its coiled state illustrated in Figure 11 to a less coiled, or uncoiled, state in the direction of arrow 5A. In unrolling, the resilient member 420 is arranged to exert pressure on fluid contained in a bag 512 so as to discharge the fluid via a control valve 518 and neck portion 522 of the bag. As can be seen, the outer end of the coiled spring member 520 is attached by attachment means 521, for example rivet or screw means, to the base of a housing 523 (not shown completely) . Also, containment means such as that provided by the core member of the apparatus of Figure 3 and Figure 5 is required so as to cause the coiled spring member 520 to unroll in the manner required but such containment apparatus is not shown in Figure 11 for reasons of clarity. Also, the surfaces of the coiled spring member 520 can be formed with a high coefficient of friction.

Alternatively, such surfaces can be provided with mutually co-operable engagement formations, such as interlocking members. These features can assist in retaining the coiled portion of the spring member 520 in a coiled state and to assist the uncoiling of the spring member 520 in a controlled manner along the complete length of the bag 512. The spring member 520 does not then simply spring open when in the position shown in Fig. 11 and avoid dispensing the contents. Such an arrangement allows for controlled sequential unrolling of the coiled spring 520, as does the use of a flexible band described in the aforementioned UK patent document 2 229 318A.

Although the apparatus described above with reference to Figures 1-11 comprises discharge apparatus, it should be appreciated that the concept of the present invention can

also be provided for apparatus arranged to draw fluid, or any other suitable material, into a receptacle and thereby charge the receptacle. As such, a resilient member which is arranged to unroll from a coiled state to a less coiled, or completely uncoiled, state in accordance with its resilience, can be provided which is arranged to have a receptacle provided thereon, formed at least partially thereby or formed there around.

With further reference to safety aspects, the use of the device having an exposed metal spring might, in some instances, be considered inappropriate or hazardous and such dangers might be even more apparent in situations where repeated cocking of the resilient member is required. In order to improve the safety of the resilient member, the member can be coated with an appropriate material. Such material may advantageously comprise a fibre-based composite with a rubber or plastic matrix.

Thus, in operation, the unrolling of the resilient member serves to allow the available volume in the receptacle to increase, and thereby cause the pressure therein to decrease so that the fluid, or other suitable material, can be drawn into the receptacle by way of a suitable inlet opening, which may, for example, be similar to the valve and neck apparatus described above. In order to-assist the expansion of the receptacle as the coil portion unrolls, resilient means such as hinged sheet springs or spring strips can be provided in the receptacle.

It will be appreciated by those skilled in the art that apparatus embodying the concept of the present invention can be provided in many different forms and with many varied features which can, for example, depend on the nature of the receptacle contents. For example, if the contents require, the resilient member and valve member can

be provided so that the receptacle's contents can be dispensed in spray form. Such apparatus is particularly advantageous when compared with known spray dispensers in that a compressor of pressurised gas reservoir is not required, therefore rendering the invention ecologically acceptable. Also, the contents can be delivered irrespective of the orientation of the apparatus, unlike most conventional spray devices which do not work once inverted or held beyond a particular angle to the vertical.

Further, the apparatus could be provided with a trigger by which the resilient member is released so as to roll in accordance with its resilience and, also, such trigger action could also serve to rupture the receptacle so as to form the opening for discharge of its contents. As such, the apparatus of the present invention could advantageously form a simple and inexpensive fire extinguisher. Also, the apparatus could be adapted to deliver gases or fine powders in gaseous-suspension form and, for example, could therefore form a dry powder fire extinguisher.

As mentioned above, the apparatus can be arranged to operate with a full sealed receptacle which can then be ruptured or otherwise opened, for example by cutting open the neck or nozzle portion, or it can be arranged for use with an empty receptacle which first has to be filled. ^' In this manner, the resilient member can be arranged to have a suitably limited mechanical strength such that it can be deformed against its resilience by applying a pressurised feed of the material into the receptacle by way of the opening. Thus, as the appropriate material is delivered into the receptacle, the resilient member is deformed and so provided with the appropriate mechanical potential energy to cause discharge of the receptacle's contents as required. Although the embodiments of the invention

discussed above comprise a spring member which can be coiled in the direction of its longitudinal axis, in situations where higher pressures may need to be exerted on the receptacle, or greater volumes of the receptacle contents are to be dispensed, the resilient member can be arranged to coil in the direction of its shorter axis. This seeks to increase the pressure which can be obtained from a particular resilient material.

The pressure applied to the receptacle can also be increased by employing more than one resilient member and, particularly where the required travel of the coil portion of the resilient member is small, the use of low-friction materials or lubricants can be of assistance.

In some instances, the grip or the receptacle provided by the coil portion can be employed to retain the receptacle on the resilient member although, as noted above, other securing means could also be used.

Fig. 12 shows the embodiment of Fig. 1 of the present invention but with further features included so as to provide further advantages. One potential limitation with the apparatus of Fig. 1 arises due to the coiling of a bag having an upper and lower wall surface. As will be appreciated, in each turn of the coil, the lower wall surface, being located within each turn of the coil on the outside of the upper surface will extend within the coil for a greater distance than the upper surface. Thus, as the spring member 14 and bag 12 coil, there is a natural tendency for the front of the bag to move forward relative to the front of the spring member 14 located adjacent to the fluid control valve 18. Any such problem is overcome by the use of features illustrated with reference to Fig. 12. A fastening member 17 is employed to fasten the rear portion of the bag 12 to the rear portion of the spring

member 14 and a flexible tubular coupling 25 is provided between the front end of the bag 12 and the valve 18. Such features advantageously prevent the bag 12 from sliding forward rather than sequentially emptying the contents of the bag 12 during the coiling of the spring member 14 in the direction of arrow A in Fig. 1. The flexible coupling 25 can comprise any appropriate form of sliding coupling for example an elastically deformable tube member.

An alternative to the use of features as disclosed with reference to Fig.12 is to secure the front of the bag 12 adjacent the valve 18, or provide a rigid coupling therebetween, and to form the spring member 14 with low- friction surfaces which allow for slippage between the bag 12 and the coiling portion 26 of the spring member 14.

Fig. 13 is a plan view of a spring member arranged to coil about a receptacle. The spring member comprises a coil portion 610 and a flat forwardly extending portion 612 which receives a bag having a contents-containing region 614 which comprises a narrow section 616 upstream (in the direction of movement of the coil portion 610 in the direction of arrow A) of a wider contents containing portion 618. As will be appreciated, the section of the bag comprising the narrow portion 616 only contains a minor volume of the contents relevant to the volume contained by the wider portion 618.

The provision of such a bag having sections of different capacity along its length in the direction of travel of the coil portion of the spring 610, has particular advantages associated with the movement and control of the coiling spring. The coiling of the spring 610 can be employed to drive functional requirements of the apparatus over and above the mere delivery of the contents of the bag. For example, the moving coil of the spring can

be arranged to advance and/or retract a needle member associated with the outlet of the bag. Thus, with reference to Fig. 13, when the coiling spring 610 moves over the portion 616 of the bag having only a narrow content-containing portion, the resistance presented by that narrow portion to the movement of the coiling spring in the direction of arrow A is reduced. During this movement the driving power provided by the movement of the coiling spring 610 can be employed to advance the position of a needle, or some other applicator, associated with the outlet of the bag so that once the coiling spring 610 reaches the portion of the bag 618 having a content containing section extending across the width of the bag, the needle has previously been moved into an appropriate position and expulsion of the contents of the wider section 618 of the bag can commence as appropriate. As will be appreciated, the pattern presented by the actual contents containing portion of the bag can be varied, when considered in plan view, so as to control the rate and extent of movement of the coiling spring as required. In the embodiment illustrated in Fig. 13, the use of the narrow content-containing section of the bag 616 is useful for priming the needle prior to the dispensing of the complete contents of the bag. Further, the Fig. 13 embodiment could be achieved by attaching the needle to a plate member which is arranged to slide along the side the bag and which plate member is driven by means of a lug protruding from a coil member provided in the centre of the coiling spring 610. Further, a plate can be provided with track, or channel, means formed in its surface which, combined with a lug member which is flexibly coupled to the aforementioned core member in such a manner so as to allow for radial movement in a direction substantially perpendicular to the direction of travel of the coiling spring 610, can therefore allow for a variety of movements of a needle to be achieved. Once the coiling spring 610

has reached the end of its travel, the lug can be arranged to be released from the plate by movement in an appropriate radial direction and the needle can then be drawn back into the body of the device by means of a resilient return member, for example a return spring. With the provision of such a movable needle, it is particularly advantageous to connect the needle to an outlet of the bag by way of a flexible conduit member such as a flexible tube having an internal bore of similar dimensions to the bore of the needle. In priming the needle with the small amount of the contents of the bag while the coiling spring 610 moves over the narrow portion 616 of the bag, air can advantageously be exhausted from the bag and needle.

It will therefore be appreciated from the above description that the apparatus can be provided with means for programming the movement of the coiling spring.

In a further advantageous aspect of the present invention, the resilient member is arranged to exhibit a non-constant force on the receptacle. Such a resilient member can be achieved by providing variations in the radius of curvature of the member, or by providing variations in the width or thickness of the member. This provides for a driving member for the expulsion of contents from a receptacle which can execute a pre-programme series of pressure variations as the resilient member coils or uncoils. Elastomeric members can be advantageously pre¬ programmed in this manner by varying the tension on the elastomer and/or the rolling characteristics of the incompressible layers or matrix. For example, if a resilient member is arranged to roll-up with the receptacle, the resistance to the rolling motion of the coil portion of the resilient member increases as more of the receptacle is coiled within the coil portion. Thus, during the rolling travel of the coil portion, the

resistance to its motion increases and, in order to achieve a constant expulsion force on the contents of the receptacle, the resilient member can be advantageously formed so as to provide for an increase in the force exerted on the receptacle and its contents so as to counter-act any increase in the resistance to the rolling motion of the coil portion of the resilient member presented by the receptacle. In this manner, the rate of which the contents of the receptacle is discharged can be maintained at a substantially constant level. In order to achieve such a variable-force resilient member, the resilient member may have a width, or thickness, that varies in the direction of motion of the coiling portion thereof or alternatively, or in addition, the resilient member can be formed from tempered steel which has been subjected to known heat treatment so as to exhibit a variation in the force exerted by the coiling spring during the motion of the coiling portion thereof.

Fig. 14 is a side elevational view of a housing apparatus 620 for use with the embodiment of Fig.l of the present invention. The apparatus comprises a handle member 622 having a lever 624 extending therefrom and into a spring housing 626 for engagement with a core member 628 which is arranged to be formed within the coiling portion 20 of the spring member 14 of Fig. 1. The housing apparatus of 620 of Fig. 14 serves as a means for unwinding, or cocking, the resilient member so as to allow for replacement of the receptacle thereon. The hand portion of 622 is pivotally mounted by way of a pivot means 629 to the spring housing 626 such that when the handle portion 622 is pivoted in the direction of arrow B, the lever 624, and thus the core 628, are drawn rearwardly along the spring housing 626 in the direction of arrow C. This serves to unwind the coil portion 20 of the spring member 14 of Fig. 1 as is required for placement of the

receptacle 12 thereon. It will of course be appreciated that the apparatus of Fig. 1 is to be positioned in the housing 620 of Fig. 14 so that the nozzle 18 is located to the left of the housing 620 as shown in Fig. 14.

Figures 15a and 15b illustrate further features of the embodiment of the present invention which prove particularly advantageous for recharging, or filling, the receptacle. As can be seen in Figure 15a, a receptacle and spring member, similar to that described with reference to Fig. l, are located in a telescopic housing 632 having two slidably engaged cylindrical portions 634, 636 (see Figure 15b) . In Figure 15a, the apparatus is shown with the resilient member in its maximum coiled state and with the receptacle empty and the contents having been expelled via the slow control valve. The sliding engagement between the two cylindrical members 634, 636 of the telescopic housing 632 is arranged to be completely or substantially air¬ tight. In this manner, and with reference to Figure 15b, when the outer of the two cylindrical portions 634 is moved in the direction of arrow A in Figure 15b, a complete or partial vacuum within the housing 632 is formed. Thus, when it is required to fill, or re-fill, the receptacle, the control valve can be opened so that the internal region of the receptacle is in communication with the fluid to be introduced into the receptacle and the outer cylindrical portion 634 of the telescopic housing 632 is moved as shown in Figure 15b. The vacuum thereby formed causes entry of the fluid into the receptacle via the control valve and this filling of the receptacle serves to urge the coiled spring portion to the left as shown in Figure 15b so as to achieve self-cocking of the spring member. If, however, the resilient member provides for a coiling force that cannot be overcome by the entry of the fluid into the receptacle, engagement means can be provided between the outer cylindrical portion 634 of the housing 632 which

serve to engage the coil member associated with the coil portion of the resilient member so as to assist in the cocking thereof. Such apparatus can prove to be particularly suitable for use with medical injection or infusion devices in which the receptacle can be attached to a standard syringe needle and in which the receptacle can then be filled from a rubber-diaphragm closed bottle of a nature normally used to store such fluid. This can advantageously assist in reducing, or avoiding, the need to supply fluid drugs in any particular form of packaging and obviates the need for any special training requirements for the staff or patients since the procedure is somewhat similar to that used for drawing fluid into a syringe.

It has been mentioned above that a variety of different materials can be provided for the resilient member and Figures 16a and 16b, and Figures 17a and 17b illustrate details of particular materials that could be used for this purpose. One form of resilient coiling/uncoiling member can be formed from elastomers. Such a member could be made from a layer which is relatively incompressible in the desired direction of coiling but which offers little opposition to the coiling force, and which is bonded to an elastomer layer which is stretched, or pre-tensioned, to provide for the required coiling/uncoiling force. The incompressible layer can be formed from a composite in which the isotropy of the material is controlled by the location and direction of the fibres. One such material 638 is illustrated in Figures 16a and 16b. Figure 16b is a cross-section along the lines b-b of Figure 16a and shows a stretched elastomer layer 642 located above a layer of fibres 640. The direction in which the fibres 640 extend is also illustrated in Figure 16a. Such an arrangement can provide for a true constant- force device in the same manner as the spring members disclosed with" reference to Figures 1-6 above.

As an alternative, a series of blocks, or rods, which are hinged and joined by tape, or embedded, in a flexible matrix so as to form a material with the desired characteristics, can be provided. Such a material 644 is illustrated in Figure 17a and 17b and comprises a series of hinged blocks or rods 646 which are tape, or fibre, linked and located below a stretched elastomer layer 648.

Materials of the nature illustrated with reference to Figures 16a, 16b and Figures 17a, 17b overcome potential safety hazards that can be exhibited by metal springs and as discussed above. Also, through appropriate formation of the material for such a resilient member, it is readily possible to provide a resilient member exerting a variable force which may, as will be appreciated from the above, assist in achieving a constant flow of the contents from the receptacle.

Figures 18a and 18b illustrate one particular complete construction for apparatus embodying the present invention. The apparatus comprises an infusion pump 650 which, from a cutaway portion of the plan view of Figure 18a, and the part elevational view of Figure 18a, employs a spring member 652 arranged to coil in the direction of arrow A in Figure 18a so as to roll-up a flexible bag 654 containing a liquid drug. The drug is expelled from the flexible bag 654 via a nozzle 656 and outlet valve 658 and subsequently through an outlet tube 660. As will be appreciated from Figure 18b, the housing for the infusion pump 650 can be provided in any particular form which may advantageously provide for a snug-fit against an appropriate part of the human body.

Also, the apparatus may be arranged such that a plurality of separate receptacles can be deformed by the resilient member and, if required, the contents of the

receptacles can be arranged to be mixed at the point of discharge.

Further, although not illustrated in the accompanying drawings, other advantageous features may comprise a transparent receptacle and/or container for viewing the contents, means for metering the change in contents and means for indicating the amount of contents in the receptacle.

The metering means can comprise a plurality of different sized passages, one of which is selected as required for the charging or discharging of the receptacle. Alternatively, the metering means can comprise rotary- digital-watch type escapement means.

The contents indication means may comprise markings on the receptacle, or a housing if employed. However, in one particularly advantageous form, the position of the coil portion can be employed on an indication of the quantity of contents in the receptacle. Indicator means can then be provided for movement with the coil portion.

Also, a variety of means can be provided for achieving the filling, or re-filling, of the receptacle. For example, a selectively operable resilient member can be employed so as to uncoil (or as required coil) the resilient member illustrated in the drawings in a manner so as to allow for the refilling of the receptacle and said selectively operable resilient member can then be removed or disengaged so that discharge of the contents of the receptacle can be achieved as described with reference to the drawings.

It can therefore be seen that the present invention can be embodied in dispenser apparatus for use in any

situation where an appropriate material, whether in fluid, gel or other form, is required to be dispensed and, as an example of such diverse application, the present invention could be embodied in a self-pressurising water supply means where mains water is not readily available, for example in a caravan.

Apparatus embodying the present invention is inherently reliable, simple and inexpensive to manufacture and maintain.

It will be appreciated that other modifications and variations may be made to the embodiments described and illustrated within the scope of the present application.