Patent Publication Number: US-2022212856-A1

Title: Beverage container holder

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to holders for beverage containers, for example to allow a user to hold a hot or cold beverage container without their hand becoming too hot or cold. In particular the invention relates to such holders which allow a user to drink from them in a safe, pleasurable, and convenient manner. 
     Beverage holders are known which aim to maintain the temperature of a beverage. Such containers may be divided into two broad categories. Each of these categories suffers from a number of drawbacks. 
     A first category is a flexible, tight-fitting sleeve, typically made of neoprene foam or similar materials. While relatively cheap, these holders lack efficacy in maintaining the temperature of the beverage. In addition, the sleeves are usually shaped and sized so as to fit only a single size of beverage holder, and consequently multiple sleeves must be purchased if a user is to be able to achieve the desired effect across a range of shapes and sizes of beverage containers. 
     A second category is a more rigid variant for encasing the beverage container, formed from plastic or metal. In order to allow a variety of sizes of beverage containers to be fitted into the holder, the rigid walls provide a cavity typically somewhat larger than many of the containers they are intended to hold. Not only does this provide an air gap through which convective heat transfer can occur between the outside environment and the beverage container, this can also lead to issues when a user tries to drink from the container. As the user tilts the container to their mouth to drink, in some cases they will need to exert a force with their mouth on the container while drinking to prevent the container from falling out of the holder and hitting them in their face. Some users find applying such a force while drinking detracts from their enjoyment. 
     In addition, the cavity of such devices is typically unsealed in the sense that convective heat flow between the drink and the environment, which can accelerate the process of the beverage reaching the equilibrium with the environment (that is for cold drinks to become warm and for hot drinks to become cool) is typically substantially unrestricted in such devices. 
     Some attempts have been made to address these issues with the second variant, but similar to designs in the first category discussed above, these tend to be tailored towards a particular size of beverage container, and so lack widespread applicability—a user must buy multiple holders and/or lids and switch between them each time they change beverage containers. In addition, these designs usually grip the beverage container very firmly and make it difficult for a user to remove an empty beverage container to empty the holder for insertion of a new, full, container. 
     The present invention aims to address some or all of these drawbacks. 
     SUMMARY OF THE INVENTION 
     Disclosed herein is a holder for a beverage container, the holder comprising: a base; a side wall defining an opening through which the beverage container is insertable; and a collar located within the opening; wherein the side wall and the base together define a cavity for receiving the beverage container; and wherein the collar is adjustable between a first configuration for contacting a first size of beverage container and a second configuration for contacting a second size of beverage container. 
     The opening is located at the other end of the side wall from the base, that is, the side wall spaces the base apart from the opening. In other words, the length of the side wall plays a part in determining the size of beverage container which can be contained within the holder. The portion of the side wall nearest the opening is referred to as the rim. The collar is located at or near the rim of the side wall in many examples, although in some cases it may be spaced some distance into the cavity, for example between 1 cm and 5 cm below (i.e. closer to the base than) the rim. In general, the direction perpendicular to the base pointing into the cavity will be referred to as upward. Directions aligned with (or anti-aligned with) this direction will be referred to as axial. Circumferential directions are those which lie on or in the side wall and extend around the cavity. 
     The holder and the cavity are both usually generally cylindrical, but in some cases one or other (or both) may be a different shape. In general, the opening and/or the collar is/are therefore circular. 
     The collar defines an aperture and is adjustable to adapt the size of the aperture to the size of a particular beverage container. That is to say, the collar provides an adjustable aperture, which is selectively adjustable to restrict the effective size of the opening. The collar is therefore adjustable (leading to a change in the aperture size) while the opening is defined by the side wall and is not itself directly adjustable, it is simply partially obstructed by the collar with the extent of such obstruction being determined by the size of the aperture in the collar. Note that in some examples the widest of configurations of the collar may cause substantially no obstruction of the opening. 
     For example, by matching the shape and size of the aperture to the outer surface of the beverage container in question (as e.g. a first size of container in the first configuration), the holder is easily adapted to that type of beverage container. A user can insert a first size of beverage container, drink from it until it is empty and remove that container. Should the user wish to have a second beverage from a container of the same shape and size, it is a simple matter for them to simply replace the empty container with a new, full container, secure in the knowledge that the holder is already adapted to receive beverage containers of that type. 
     On the other hand, in the event that the user wishes to drink from a beverage container of a different size, either the new container will be too large to fit into the aperture in the collar or the collar will be too large to contact the container. With a simple adjustment (e.g. to the second configuration), the user can adjust the collar to once again contact the outer surface of the new size of beverage container. 
     In either case, the collar contacting the outer surface of the first or second size of beverage container in the first or second configuration respectively provides inhibition of heat flow by conduction, convection and/or radiation, thereby helping to maintain the beverage at the desired temperature. 
     Of course, other secondary benefits exist. For example, the user may prefer to loosen the aperture (e.g. set the collar to the first configuration) to ease insertion or removal of a beverage container to through the widened aperture. The collar can then be set to e.g. the second configuration when the beverage container is inserted into the cavity, in order to contact the beverage container and restrict heat flow between the cavity and the outside environment. 
     This allows a single holder to be used with at least two sizes of beverage container, although as discussed below a single holder may be appropriate for more than two sizes of container. Indeed, in many cases, a single holder may be suitable for any sized container within a given range of sizes. This allows a user to set the collar to the desired size and continue to replace beverage container of the same size as often as desired with no adjustment at all. They can also replace empty beverage containers with full ones of a different size by making a simple adjustment to the collar. 
     The collar is arranged to restrict the opening in the second configuration by narrowing the aperture defined by the collar. In other words, the collar is at its widest in the first configuration and is narrower in the second . Where the holder is generally cylindrical and the collar is circular, then the constriction of the opening generally includes the collar forming a circular shape of smaller radius in the second configuration than in the first configuration. In both configurations, the circular collar is usually centred on the cylinder&#39;s axis. 
     The collar is arranged to contact beverage containers towards the upper portion of a particular beverage container, which results in the bulk of the volume of the beverage container (and therefore also most of the beverage itself) being enclosed within the cavity. A portion of the beverage container may nevertheless protrude outward from the opening to allow a user to drink from the beverage container in the usual manner. 
     As noted above, in some cases the collar is circular or is shaped as a portion or arc of a circle. For the avoidance of doubt, as used herein “circular” includes shapes derivable from small deformations of circles, and therefore includes rounded shapes such as ellipses and ovoid shapes. Ellipses with an eccentricity of 0.3 or lower are included within this definition of circular. More generally, the opening and/or the collar may be shaped so as to have no corners, that is to be generally rounded and formed only of smooth curves. These shapes not only allow the collar and the opening to conform to the circular cross-section commonly seen in beverage containers, but in avoiding sharp corners can help the collar to contract uniformly and thereby allow the collar to contact the beverage container in a smooth manner, without becoming distorted or ruffled. 
     Generally, the collar is the same general shape in first and second (and intermediate) configurations, but in some cases the transition process may cause the shape to distort between the two configurations. Of course, even where the collar is the same shape, the second configuration restricts the size of the opening, so the collar is a smaller size in the second configuration, relative to the first configuration. 
     As noted above beverage containers are provided in a variety of standard dimensions and the size of the collar in the first and second configurations can be selected to conform to these dimensions. That is, to constrict the opening sufficiently to contact the outer surface of the first or second size of beverage container in the first or second configurations, respectively. To conform with this, the collar may have an internal dimension of between 50 mm and 75 mm at its widest part in both of the first and second configurations (with the internal diameter of the second configuration being smaller than the internal diameter of the first configuration). For example, the first configuration may have an internal diameter of 75 mm or slightly narrower to allow any of the standard sized bottles or cans to be inserted into the cavity (and optionally contacted or even gripped). The second configuration may have an internal diameter of 50 mm or slightly wider to allow the smallest of standard bottles or cans to be contacted (and optionally gripped) by the collar. 
     As used herein “internal diameter” means the distance from a point on the inner edge of the collar to an opposed point on the inner edge of other side of the collar. As noted, the distance is measured at the widest part of the aperture defined by the collar, which is to say the internal diameter as set out above which gives the largest value. For circular collars, this is simply the diameter, for elliptical collars, this is the major axis. For square collars, this would represent a diagonal taken across opposed corners. 
     In some cases, as discussed below in more detail, the holder may be provided with multiple interchangeable collars. In such an example the collars can be selected to span the range above in an overlapping manner. For example, a large collar may transition between a first configuration of 75 mm internal diameter and a second configuration of 65 mm internal diameter. A medium collar may transition between internal diameters of 57 mm and 67 mm, and a small collar may transition between internal diameters of 60 mm and 50 mm. Other example dimensions to span the range will be apparent to workers in the relevant technical field. For example, the range may be spanned by a different number of collars, such as two to eight collars. In some cases, the collars may have maximum or minimum dimensions outside of the range 50 mm to 75 mm, for example to accommodate non-standard beverage container sizes. 
     The collar may extend substantially around the opening. That is, the collar may extend around the opening for a full 360° circuit, or for a full circumferential circuit. In some cases, the collar may extend circumferentially around at least 75% of the opening, in other cases, at least 90% or even 95%. 
     The collar may be arranged to form a seal at least part way around an outer surface of the beverage container, when adjusted to an appropriate size for contacting the beverage container. 
     Whether or not the seal extends around the entire circumference of the opening, the collar may be arranged to form a seal which is discontinuous around the outer surface of the beverage container, e.g. formed as several separate pieces circumferentially spaced around the opening. In other cases, the seal may be continuous (i.e. a single piece) and airtight, thereby strongly inhibiting convective heat flow between the environment and the cavity. 
     Note the adjustable nature of the collar allows the seal to extend around the beverage container, since it is not a problem if a partial vacuum forms within the cavity. A partial vacuum may form when a cold beverage container is inserted, and a full seal is formed. The cold beverage container could then cool the air in the cavity and reduce the pressure. This in turn would prevent the container from being pulled out of the cavity, even when the container is empty, and the user wishes to replace it. Not only is this problem solved by providing a collar which can be transitioned to a wider configuration thereby equalising the pressure and allowing removal of the beverage container, but the partial vacuum may help hold the beverage container in the holder and reduce the risk of the container slipping out during drinking. 
     In cases where a hot beverage is used, the situation is reversed, and it may be preferable to use a discontinuous seal to allow pressure to equalise. In any case, the adjustable nature of the collar can be used to increase the aperture size slightly to prevent a full seal forming, if desired. 
     The cavity is shaped and sized to allow various standard sizes of beverage container to fit inside. For example, it is common for beverages to be supplied in cans having a range of diameters between about 53 mm and about 66 mm, more specifically between about 53.3 mm and 66.2 mm. The height of these cans also varies between about 111 mm and 194 mm, more specifically between about 111.2 mm and 193.7 mm. 
     The holder may also be adapted to hold beverage containers in the form of bottles. Typical sizes for bottles range between about 53 mm and about 66 mm, more specifically between about 53.3 mm and 66.2 mm in diameter. The height of these bottles also varies between about 220 mm and 250 mm, more specifically between about 218 mm and 246.5 mm. In addition, bottles tend to have a non-uniform profile in which the bulk of the volume exists in a lower body portion, with a thinner upper portion (called the neck) being provided for assisting in pouring and/or drinking. For this reason, the collar may be arranged to contact the bottle at or near the region where the body transitions to the neck, sometimes called the shoulder if the bottle. 
     The holder may further comprise an actuator movable relative to the side wall arranged to cause the collar to transition between the first configuration and the second configuration. This provides a convenient way for the user to alter the configuration of the collar. The actuator may be movable relative to the side wall in a rotational and/or an axial direction. This allows for an intuitive operation of the collar. Where both rotation and axial motion are used, the actuator can include a screw thread. Other examples may include only pushing or only rotating (and locking or clipping in place once the collar has transitioned between configurations). 
     Where the actuator motion includes axial motion, it can press downward on the collar and cause it to flex outward, for example, by squeezing the collar between a part of the actuator and an internal shoulder. 
     The motion of the actuator may cause the collar to transition continuously between the first and second configurations. In doing so, the collar may pass through a series of intermediate configurations. 
     The motion of the actuator may be graduated, and the graduated motion may correspond to one or more intermediate configurations of the collar between the first and second configurations. For example, the motion of the actuator may be controlled with one or more detents to indicate desired intermediate positions. Each intermediate position may advantageously correspond to the collar contacting a container of a particular size. In this way, one collar can be arranged to contact a number of different container sizes. 
     In other examples, the motion of the actuator may be stiff enough that it can rest securely at any intermediate position (corresponding to a collar having an internal diameter between that which it has in the first configuration and that which it has in the second configuration). In such a continuously adjustable system, the actuator may be provided with a series of alignment markings to indicate when the actuator is in an appropriate position to contact beverage containers of particular sizes (e.g. commonly encountered container sizes). The markings can be pictures, numbers, words, or combinations thereof. For example, the markings may refer to “large can”, “normal can”, “slim can”, tall bottle, etc. to provide an indication to a user of a suitable setting for the beverage container they are seeking to insert. Pictures could also be used to indicate aperture sizes of the intended beverage container. Alternatively, numbers could be used, either measuring the diameter of the aperture in mm, cm, inches, etc. or as a scale from 1 to 10, whereby a user learns or is instructed which number is most appropriate for a given container type. 
     In some examples, the actuator is selectively lockable at least one position, the at least one position corresponding to the first configuration, the second configuration or to an intermediate configuration of the adjustable collar. This can allow a user to ensure that the collar remains in the contacting position for the beverage they are enjoying at that time. For example, the actuator may be configurable in a free mode in which it can be freely moved to set the internal diameter of the aperture in the collar, and a locked configuration in which the actuator cannot move, and the aperture internal diameter is fixed, at least until the actuator is unlocked. 
     The collar may comprise a strip of flexible material. This is a simple collar, but one which may easily be tailored to produce the desired effect. 
     The collar in the form of a strip of flexible material may be arranged to lie substantially along an internal wall of the cavity in the first configuration and a portion of the collar may be deflected away from an internal surface of the side wall in the second configuration. This deflection causes a constriction of the aperture and allows the beverage container to be contacted. When the collar lies flat against the wall, the aperture is larger, which allows the holder to be used with wider beverage containers and may also assist in removal and insertion of beverage containers by allowing a user to break contact (and optionally gripping) between he collar and the beverage container. The flexible strip of material may have elastic properties, so that it biases itself towards the first configuration. This means that the actuator need only force the collar into the second configuration, it need not force it back into the first configuration. That is the actuator can be arranged to exert e.g. only a push force and need not also pull. 
     By “lie substantially along”, it is meant that the strip of material lies as flat as possible against the internal surface of the side wall, given the material and dimensions. 
     In the second configuration, a pair of opposed edges of the strip may remain adjacent to the internal wall and an intermediate portion of the strip may curve away from the internal wall. This forces the flexible strip into a “C” shape in cross section. The edges remain in contact with the side wall, thereby forming a stable arrangement and the central portion extends towards the centre of the opening to contact the beverage container. The central portion is located between the two edges, and the edges run broadly circumferentially around the inner surface of the side wall (in other words around the opening), with one edge being an upper edge, nearest the rim of the opening and the other edge being a lower edge, located nearest the base of the holder. One or both of the edges may be joined to the side wall and/or the actuator. For example, the motion of the actuator may be to press the upper of the two edges towards the base of the holder. The lower of the two edges may be prevented from moving toward the base by a shoulder supporting it, and/or by being fixed to the side wall. The downward force on the upper of the two edges thereby forces the central portion of the strip to flex outward and constrict the aperture. 
     In other examples just one edge may flex outward when actuated by the actuator. For example, the lower edge may once again be fixed in place and the actuator may be wedge shaped in profile and act to force the upper edge away from the side wall and cause a constriction of the aperture with the innermost part of the collar being the upper edge. Where the collar is fixed to the actuator, the situation may be reversed, e.g. the lower edge may be forced against a tapered internal shoulder which acts to force the lower edge away from the side wall and leads to a constriction of the aperture with the innermost portion of the collar being the lower edge this time. 
     In yet further examples, the first and second configurations may comprise a pair of opposed edges of the strip remaining adjacent to the internal wall and an intermediate portion of the strip curving away from the internal wall, forcing the flexible strip into a “C” shape in cross section. The difference between the two configurations is seen in the degree of curvature of the “C” shape with the second configuration having a flatter and wider “C” shape than the first configuration has. In this case, the first configuration may be one in which the collar does not lie substantially along the internal surface of the side wall but is in any case on average closer to the wall than is seen in the second configuration. 
     The adjustable collar may include one or more indents, creases, or perforations. This can encourage the collar to flex in a desired location or simply allow the collar to constrict the opening without ruffling and/becoming damaged. 
     The collar may retain its angular position relative to the side wall during transitions between the first and second configurations in some examples. In other examples, the collar is rotationally affixed to the actuator and rotates with the actuator, relative to the side wall. This can help ensure that the collar does not twist in cases where the actuator moves relative to the side wall in a rotational manner to actuate the collar. 
     In any case the collar, where it is a strip as in the example above, rotates as a single element, meaning that its upper and lower edges remain rotationally aligned with one another and the strip is not twisted during the transition. This can help to ensure that the deformation of the collar results only in narrowing and does not strain the collar in twisting it in undesirable ways. 
     Also disclosed herein is a device adapted to hold a beverage container having any size within a range of sizes, the device comprising: a base; a side wall extending away from the base and defining an opening through which the beverage container is receivable into a cavity defined by the base and the side wall; and a pliable collar spaced away from the base and located within the cavity, the collar extending inwardly into the cavity and having an aperture through which the beverage container is insertable such that the collar deforms to cause an inner edge of the aperture to contact and grip the beverage container; wherein the opening has a first width, the aperture of the collar has a second width, the second width being smaller than the first width and wherein the first width is selected to be larger than the diameter of the largest beverage container in the range of sizes and the second width is selected to be smaller than the smallest beverage container in the range of sizes. 
     In some cases, a ratio of the second width to the first width is less than or equal to 0.9. That is to say the ratio, r, may in some cases satisfy 0.85≤r&lt;0.95, in other cases, this may be interpreted as meaning 0.895≤r&lt;0.905. In other examples, the first width is larger than one of:66.2 mm, 64.1 mm, 63.5 mm, 60.7 mm, 59.3 mm, 58.1 mm, 57.5 mm, or 56.1 mm, and the second width is smaller than 64.1 mm, 63.5 mm, 60.7 mm, 59.3 mm, 58.1 mm, 57.5 mm, 56.1 mm, or 53.3 mm. As will be apparent from other parts of this application, the choice of these values ensures that the largest beverage container in the range of sizes will fit through the opening and the smallest beverage container in the range of sizes will be contacted and/or gripped by the collar. Note that the various combinations of sizes from the lists given above allows for adjacent sizes of commonly found beverage containers to be accommodated, or by selecting upper and lower ranges spaced further apart in the list, the range of sizes can be expanded to encompass three or more container sizes. 
     This device is able to receive beverage containers of any size (within the preselected range) by virtue of the pliable collar, which is able to deform to contact and grip the outer surface of the container. This means that a single device can be used to hold a range of container sizes. This in turn is beneficial as it simplifies operation for a user and represents a more efficient use of resources as only one collar size need be purchased and supplied. In principle the collar can be used to contact a wide range of container sizes, assuming that it is able to deform enough to grip the wider ones, and that the aperture is small enough to allow smaller containers to be contacted. In some cases the stiffness of the collar may be selected based on the range of beverage containers intended to be accommodated, with collars designed for a larger range of intended beverage containers (i.e. those intended to deform the most when the largest size of container is inserted) being less stiff to allow the required amount of deformation to occur without inducing undue strain on the collar or excessive pressure being exerted on the beverage container. 
     The collar is pliable, that is to say formed from an elastic material so that the collar can stretch and deform to allow the beverage container to be inserted, and which evens out strains in the collar. This helps to hold the beverage container centrally within the aperture since off centre location of the beverage container strains the collar unevenly, causing uneven forces to be applied to different sides of the container and bring the container back to an arrangement where it is located in the centre of the aperture, via the elastic interaction. This also spreads out the force on the beverage container and can help to avoid buckling or other damage caused by excessive build-up of force. 
     Where it is stated that the collar deforms, specifically this means that an inner edge of the aperture deforms while the outer edge (adjacent to the side wall) remains in substantially the same position and shape. The deformation takes the form of the collar being pushed downward into the cavity (towards the base) and the inner edge stretching to fit the width of the beverage container, as the beverage container is pressed into the cavity, through the aperture. The inner edge of the aperture may sometimes be referred to as the perimeter of the aperture. The deformation of the collar in this way can reduce or eliminate convective heat flow into or out of the cavity by forming a full or partial air seal. Even partial seals can disrupt air flow by acting like a baffle and reduce the convective processes which can hasten the beverage container&#39;s return to ambient temperature. 
     The range of sizes ranges from a largest intended size of beverage container and a smallest intended size of beverage container. The width of the opening places a physical upper limit on the size of container which could be inserted since nothing wider than this will fit into the cavity. Similarly, it is apparent that the collar will not operate correctly if a beverage container smaller than the aperture is inserted, since the container will be able to pass through the aperture without being gripped. The upper and lower ends of the range may be selected to encompass all beverage containers of standard sizes, or only a subset of this range in some examples. For example, there may be provided a “large container” version of the device covering the upper end of the range and a “small container” version of the device covering the lower end of the range. In other examples, different versions may be adapted to different classes of beverage container, for example a “bottles” version and a “cans” version, wherein the collar material properties may be adapted to best deform for and grip glass and aluminium or steel respectively. 
     Where the opening is referred to as having a width, this means the narrowest width between an open end of the side wall and the collar, in cases where the internal surface of the side wall is not flush, but has different widths at different axial locations. In other words, there may be circumferential recesses or protrusions in the internal surface of the side wall, and the width is then defined as the narrowest such portion, since it is the narrowest portion which limits the size of container which can be inserted into the device. Advantageously, the width of the narrowest portion between the open end of the side wall and the collar may be selected to be no wider than the narrowest portion of the cavity between the collar and the base, thereby providing an indication to a user of the maximum size of container which can be inserted into the device. Since the parts of the cavity between the collar and the base are usually not visible to a user (at least not clearly), this arrangement can help a user gauge whether a given container will fit without expending unnecessary effort. 
     For the avoidance of doubt, the ratio of the first width to the second width is calculated as the width of the aperture divided by the width of the opening. While the above discussion sets out that this ratio may be 0.9 or lower, in some cases, the ratio may be much lower than this. In fact, as long as an aperture exists, there is no real lower limit on this value, although it becomes progressively harder to insert large containers into ever smaller cavities. In conjunction with an effective lower limit on the size of containers means that it is rare for a ratio lower than about 0.3 to be desirable or necessary. In fact, most standard beverage containers can be received in devices having an appropriately chosen opening width (e.g. about 73 mm or 75 mm) and a ratio of about 0.65 to 0.7, as will be apparent from the detailed discussion below. In any event, it is this ratio which determines the range of sizes of beverage container which the device is adapted to receive. 
     On the other hand, the ratio of 0.9 or lower ensures that the device is able to receive at least two different standard sizes of container, since the relative change in width between consecutive standard beverage container sizes is usually less than 10%. It will be apparent that smaller values for this ratio are associated with larger ranges of beverage container sizes which can be received in the device in the intended manner—i.e. with the collar deforming to grip and contact the outer surface of any size of container between a smallest and largest intended size of container. Wider containers deform any given collar more than smaller ones, when inserted through the aperture. 
     Another way to think of this ratio is that the collar occupies at least about 19% of the cross-sectional area of the cavity (for cavities which are approximately cylindrical and having generally annular collars). For the lower limit of the width ratio suggested above, the collar would occupy about 91% of the cross-sectional area of the cavity where the cavity is cylindrical, and the collar is annular. Other shapes for collars and cavities may lead to different area ratios. 
     As used herein “width” (or sometimes “size”) means generally the distance from a point on the inner edge of the aperture in the collar to an opposed point on the inner edge of the opposite side of the collar (or equivalently from a point on the inner edge of the opening to an opposed point on the inner edge of the opposite side of the opening). For circular collars/openings, this is simply the diameter of the circle. For non-circular shapes, the different roles played by the aperture and the opening lead to the following definition. The opening operates to set an upper limit on the size of container which can be received, meaning that the main dimension if interest in characterising the opening is the shortest distance across the opening (suitably qualified), as this will ultimately limit the size of container which can be received. Similarly, the aperture sets a lower limit, but will operate as long as it is able to contact and grip a container. Therefore, once more the shortest distance across the aperture (again, suitably qualified) is the dimension of interest in determining whether a particular example will operate as intended. Consequently, in non-circular shapes the width refers to a distance measured between a point on the opening/aperture through the centroid of the opening/aperture (respectively) to the other side of the opening/aperture. As this gives many possible widths depending on the starting and finish points of the measurement, the width as used herein shall be the shortest distance possible to measure in this way. For elliptical collars/openings, this is the minor axis of the ellipse. For square collars, this would represent the side length of the square, and so forth. In general, it is preferable not to have sharp corners in the shape of the aperture as these can be regions in which force concentrates and may lead to tearing. 
     When used, the beverage container is generally inserted/insertable along a central axis of the cavity and/or aperture, meaning an axis which is generally perpendicular to the base and/or generally parallel to the direction in which the side wall extends away from the base, and which passes through the centroid of the aperture and/or the opening. 
     The collar is located within the cavity, meaning that the opening exists at the end of the side wall furthest from the base, such that the side wall forms a rim of the opening and the collar is located wither at the rim or between the rim and the base. The collar extends inwardly towards the central axis of the cavity. This can mean that the collar is connected to the side wall and extends inwardly from the side wall. In other examples, the collar may not be connected to the side wall but may instead be attached to a removable lid. In any case, the collar is located with an outer part adjacent to the side wall (even if it is not connected/touching), and an inner part defining the aperture. 
     The base may be closed or in some cases may have through holes or perforations therethrough. These can be used to allow condensation drainage out of the base and/or to allow pressure equalisation to occur in cases where a hot/cold beverage container would otherwise cause air in the cavity to expand/contract. 
     Also disclosed herein is a device adapted to hold a beverage container having any size within a range of sizes, the device comprising: a base; a side wall extending away from the base and defining an opening through which the beverage container is receivable into a cavity defined by the base and the side wall; and a pliable collar spaced away from the base and located within the cavity, the collar extending inwardly into the cavity and having an aperture through which the beverage container is insertable such that the collar deforms to cause an inner edge of the aperture to contact and grip around an entire circumference of the beverage container. In such a device the collar and/or the base may have through holes to assist in equalising pressure between the cavity and the surrounding environment. This arrangement can provide a good level of thermal isolation for the cavity (and also therefore for the beverage container within the cavity. In addition, designs which utilise through holes provide a balance between thermal isolation and relieving pressure differentials. As above, in such examples, the opening may have a first width selected to allow the largest size of container in the range of sizes to be inserted and the aperture of the collar may have a second width selected to still grip the smallest size of container in the range of sizes. The second width is smaller than the first width and in some cases, the ratio of the second width to the first width is less than or equal to 0.9. 
     Optionally the collar has a generally planar form. Optionally, the collar extends generally perpendicularly inwardly from the side wall. This arrangement is the case when no beverage container is received through the aperture. In other words, this is the arrangement in the undeformed shape. These each help ensure that when the beverage container contacts the collar, being inserted along a central axis of the cavity (as defined above), the beverage container contacts the collar at all locations around the collar at broadly the same time, and thereby deforms the collar equally around its circumference and prevents over stressing of the collar at any particular location. 
     Optionally, the inner edge of the collar is thicker than parts of the collar closer to the side wall. That is to say that the inner edge of the collar may be at least 1.2 times as thick, and in some cases about 1.5 or even 2 times as thick, as the parts of the collar closer to the side wall than the inner edge is. This provides a good degree of resilience to the inner edge which bears the brunt of the wear and tear from the deformation of the collar to receive the beverage container. It is not necessary to make this portion unduly thick, however, as this can lead to excessive forces being exerted on the beverage container by the collar. Where the beverage container is a can, this can result in denting or crushing the can. The values of more than 1.5, and about 2, times the normal collar thickness (itself usually around 1 mm to 1.5 mm thick) has been found to provide a good balance between resilience and safety. 
     Optionally the collar includes one or more perforations extending through the collar. These perforations are typically fully surrounded by collar material, that is to say that each perforation is a hole through the collar which does not extend to the side wall or the aperture. The perforations may have a size of between 1 mm and 5 mm diameter, for example about 3 mm in diameter. These perforations allow air pressure to equalise on each side of the collar, but do not allow significant convective heat transfer. The air pressure equalisation helps ensure that drinks which are substantially hotter or colder than the outside environment do not cause air pressure inside the cavity to (respectively) rise or fall. By allowing this equalisation, the beverage container can be safely and conveniently retained in the cavity while a user is drinking and removed when empty. 
     Optionally, the collar is arranged to form a seal at least part way around an outer surface of the beverage container, optionally wherein the collar is arranged to form a seal all the way around an outer surface of the beverage container. By all the way around it is meant that a full circumference of the outer surface of the beverage container is in contact with the collar. This allows any warmth or coldness of the beverage to be retained in the cavity, thereby retaining the beverage at its intended temperature, by preventing convective heat transfer out through the opening. 
     Optionally the cavity and the aperture have the same general shape as one another, when viewed in the direction of insertion of the beverage container, optionally wherein the cavity is cylindrical, and the collar is annular. In other words, the collar may be a ring-shape bounded by two circles, optionally where the circles are concentric. This allows the collar to be naturally fit to most standard sizes of beverage container, since most standard sizes of container are generally cylindrical, at least for the part of the container which the present device is arranged to grip. 
     Optionally the width of the aperture is less than 50 mm, optionally the width of the aperture is greater than 40 mm, wherein the width of the aperture is about 45 mm. In some examples the aperture may have a width of about 44.6 mm. These widths (in line with the above discussion on aperture width in this device) allow for the smallest standard sized beverage containers to be gripped by the collar—for example slim cans have a body diameter of about 53.3 mm, meaning that there will be deformation and gripping of even these small cans with the above aperture widths. Of course, in some cases, a larger aperture may be desirable to adapt the collar to only the upper end of the range of beverage containers, for example an aperture of around 63 mm may be suitable for gripping beverage containers towards the larger end of the range of standard sizes only. 
     Optionally the width of the opening is greater than 55 mm, optionally the width of the opening is at least 70 mm, optionally the width of the opening is about 73 mm, or even about 75 mm. In some cases, the opening may be about 65 mm (and the aperture and collar will usually be correspondingly smaller as well to account for this reduced opening size). 
     Optionally an internal surface of the side wall has an internal shoulder to provide a recess for receiving the collar as the collar deforms as the beverage container is inserted through the aperture into the cavity. This space allows the collar to deflect as far as needed to fit even the largest beverage container into the cavity, without the collar providing undue resistance to insertion, as the recess prevents a large surface area of the collar being forced into contact with the outer surface of the beverage container and thereby provide a large resistance to insertion or removal of the beverage container into/out of the cavity. In such examples, the collar may therefore be wider in total than the opening, as the outermost portion of the collar is located further away from the central axis of the cavity than the rim of the opening is. 
     There may also be a corresponding recess formed above the collar in some examples, that is located between the collar and the open end of the side wall. As noted above, the side wall may include circumferential protrusions and recesses. In other words, the side wall may not be cylindrical or otherwise have side walls which extend perpendicularly and linearly from the base, but which vary their width (or cross-sectional area) along the length of the side wall between the base and the open end of the side wall. In such cases, a recess may be formed in the side wall between the collar and the open end of the side wall which provides a space into which the collar can fold as the collar is forced upwards when the beverage container is removed—similar to the deformation of the collar when the beverage container is inserted, but inverted, since the gripping of the beverage container means that the inner edge of the collar is dragged upwards, towards the open end of the side wall, as the beverage container is removed from the device. 
     This recess operates very similarly to the shoulder and recess below the collar (described above) in that the recess provides space for the collar to fold up into, so that the collar is not forced to lie along the beverage container with a large surface area of contact. This reduces friction and allows the beverage container to be removed from the device without the user needing to exert too great a force. Providing recesses in this way (whether above or below the collar) is particularly suitable for devices which are intended to accommodate wide ranges of acceptable sizes of beverage container because the collars of such devices are (relatively) large and include a lot of material. These large collars are more prone to bunching and resisting the insertion and extraction of beverage containers, particularly where the beverage container is towards the upper end of the range of sizes of containers for which the device is designed. 
     In general, it will be appreciated that features described in relation to the two variant devices described above may be applied to the other variant, in particular those relating to the structure of the base and the side wall, or to internal features of the cavity. Specifically, the following features apply to each of the two variants. 
     The collar may extend substantially around an internal surface of the side wall. This helps provide stability to the collar which can itself interface with broadly a full circumference of an outer surface of the beverage container, by allowing the collar to connect to, or otherwise be supported by the side wall for a full circumference. 
     The collar may be generally parallel with the base. That is, the collar may be arranged with its lower edge a fixed distance from the base around the whole inner circumference of the side wall at the location of the collar. Similarly, the collar may be generally parallel with the opening, that is to say that the collar may be arranged with its upper edge a fixed distance from the opening around the whole inner circumference of the side wall at the location of the collar. For planar collars, the plane of the collar may be generally parallel with the base. 
     In some examples the collar is provided on a replaceable cap, which can assist in removing the beverage container, and also in accessing the cavity, e.g. for cleaning or insertion, replacement, inversion and/or removal of inserts. In such cases, the cap does not cover the full container, rather the upper portion of the holder which houses the collar is removable, replaceable and/or reversibly attachable. 
     In some cases, a plurality of replaceable caps may be provided, each cap having a differently sized collar. This allows a series of collars to be used depending on the desired size of beverage container. In yet further examples a taller cap may be used to accommodate a taller container. 
     In some cases, the collar itself is removable from the removable cap. This can allow a collar adapted for different ranges of beverage container size to be supplied and easily fit to a single cap (assuming that the opening in the cap is large enough to fit the largest container, of course. A user can even replace the collar entirely, if it tears, for example meaning that there is less wastage as most of the device or holder can be reused. 
     In some cases, the collar has a rough or roughened surface for gripping the beverage containers which it contacts. For example, the collar may be made from rough material such as rubber, or it may have a textured, knurled, etc contacting surface to improve grip. This can help ensure that the beverage container remains within the holder while a user is drinking. In some examples, the collar may comprise a plastic or rubber material, for example it may include natural rubbers, synthetic rubbers, silicone rubbers, thermoplastic polyurethane or the like, or any combination thereof, which can provide the desired flexibility and resilience, and can also optionally be adapted to grip the beverage containers, and tend to have excellent thermal insulation properties. 
     Whichever material the collar is made from, the collar may have a Shore durometer hardness of 25 Shore A to 90 Shore A, preferably between 40 Shore A and 70 Shore A, most preferably about 50 Shore A. In certain examples the collar material may have a durometer hardness of about 55 Shore A. 
     The base provides a support to hold the weight of the bottle and retain it within the holder. The base is usually a closed base, but in some cases may have one or more through holes. 
     The interior of the cavity may have a shoulder arranged to contact a base of the beverage container in some examples. The shoulder can be an annular structure or a series of discontinuous platforms within the cavity. This can allow the distance along the side wall between the collar and the plane at which the beverage container is supported to be tailored to particular shapes and sizes of beverage container. Indeed, in some cases there may be multiple internal shoulders within the cavity, each positioned and sized to ensure that a particular beverage container format will align with the collar at an appropriate point on the beverage container (usually near the top of cans and near the shoulder of bottles). 
     In order to achieve this, concepts of interest include the distance from the base of the beverage container at which the collar is intended to contact it and the diameter of the lowest part of the beverage container. The shoulder should extend radially inward from the side wall a distance which ensures that it will support the base of the container (e.g. where the shoulder is annular, it has an inner diameter less than the diameter of the part of the beverage container intended to be supported). The upper surface of the shoulder should be located a distance from the collar which is equal to the distance from the base of the beverage container to the region at which the collar is intended to contact the beverage container. 
     By following these concepts, it may be possible to nest a series of shoulders to form a stepped arrangement inside the cavity. This arrangement would allow a series of containers to be correctly inserted into the holder. Starting with a tall thin container which could rest on the base of the cavity and fit inside the central hole of one or more annular shoulders, progressively wider and shorter containers could be supported by successive annular stepped shoulders. This broadens the range of containers for which the holder is suitable. 
     In other cases, a series of removable and replaceable shoulders of different sizes can be included. In fact, where the shoulder is intended to be used with a single container type, there is no need to make it annular and instead a simple spacer could be provided in the form of a support column having a cross-sectional shape matched to the internal cross section of the cavity and a thickness tailored to the specific container type in accordance with the above concepts. 
     Advantageously the removable shoulders could further include a material for cooling and/or heating the interior of the cavity. Indeed, the holder itself may include a material in thermal contact with the interior of the cavity for cooling and/or heating the interior of the cavity in some examples. 
     For example, a phase change material or other material with high heat capacity could be provided in the cavity or in a removable insert. The material could then be heated up and used to ensure that hot drinks remain hot or cooled down to ensure that cold drinks remain cold (as the case may be). 
     Optionally the device further includes a removable insert insertable into the cavity prior to the beverage container being received in the cavity, to contact a lower end of the beverage container and space the beverage container away from the base. In other words, the insert can be used to change the height at which the collar interacts with the beverage container, similarly to the concepts discussed above in view of the shoulders provided in the cavity for contacting the base of then beverage container. 
     Optionally, the insert is U-shaped in profile to selectively allow insertion in two orientations, each orientation spacing the lower end of the beverage container a different distance from the base. In other words, the insert can be removed, inverted, and reinserted to select the desired distance between the collar and the place inside the cavity that the lowest point of the beverage container will rest on. In some examples the vertical walls of the U-shaped section are arranged to hold the beverage container centrally within the cavity. In other words, the insert forms a cap around the lower end of the beverage container, spacing the beverage container apart from the side wall of the cavity. This provides two points of contact which hold the beverage container centrally—the insert and the collar, thereby improving the stability of the holding. 
     In fact, since the insert can be inserted in two orientations (U-shaped in profile; ∩-shaped in profile) or removed from the cavity entirely, there are correspondingly three possible distances available between the collar and the place inside the cavity that the lowest point of the beverage container will rest on (the base, or one of the two faces of the insert). 
     Optionally, the insert has grooves in at least one surface for interfacing with the lower end of the beverage container. These grooves may be provided to grip or hold the base of the beverage container centrally, for example by interfacing with features on the base of the beverage container. In some examples, the base of the cavity may have such grooves instead or as well as the insert having them. These may again help to hold the beverage container centrally and firmly in place. 
     The side wall and/or the base may comprise rigid plastic and/or metal. For example, acrylic, polycarbonate, polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, acrylonitrile butadiene styrene, various steels, and brass (and combinations thereof) would all be suitable materials. The base and/or the side wall may be are hollow and include insulating means. For example, vacuum, aerogel, fibrous insulation and the like may all be used. This can help maintain the temperature of the beverage within the container. 
     In some cases, the holder further includes a bottle opener mounted in an exterior surface of the base. This may be either detachable or fixed in place. In any event this allows a user to ensure that they can open a bottle (e.g. a crown cork) at any time in which they wish to use the holder to hold a bottled beverage. 
     In some cases, the holder may further comprise ergonomic grips on an exterior surface of the side wall. for example, these may take the form of roughened or textured areas of material, indented portions, or indeed a material selected to provide grip such as rubber. 
     The disclosure also extends to a kit of parts, including a holder and/or device according to any the above examples and at least one replaceable shoulder, invertible insert, replaceable cap, and/or cooling or heating insert. Of course, multiple of any or each of these may also be provided as part of the kit. 
     In each of the examples above, the device is adapted to receive a beverage container into the cavity by passing through the opening and the collar. That is to say that a user can insert the beverage container into the cavity by pushing the beverage container through the opening and into the device, with the base of the beverage container going first, to place the beverage container inside the device, within the cavity. Many previous devices are designed to require the removal of a separable lid to insert the beverage container into the device, with the lid being subsequently attachable once the beverage container is within the device to secure the beverage container in place. The presently described arrangements, having either an adjustable collar or a flexible one, allows for a much simpler operation with fewer moving or removable parts, and thereby reduces the risk that a user will lose parts of the device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Specific examples will now be described in detail with reference to the accompanying Figures, in which: 
         FIG. 1A  shows a perspective view of a holder for a beverage container; 
         FIG. 1B  shows a perspective view of the holder of  FIG. 1A , shown from below; 
         FIG. 2A  shows a cross-sectional view of the holder of  FIG. 1A  prior to a beverage container being inserted and the collar in the first configuration; 
         FIG. 2B  shows the cross-sectional view of  FIG. 2A , with a beverage container received in the cavity and the collar in the second configuration; 
         FIG. 2C  shows the cross-sectional view of  FIG. 2B , having an alternate beverage container received in the cavity and contacted by the collar, the collar being in an intermediate configuration; 
         FIG. 2D  shows the cross-sectional view of  FIG. 2C , in which the collar is in the first configuration and does not contact the beverage container; 
         FIG. 3A  shows an example of the collar in detail in the first configuration; 
         FIG. 3B  shows the collar of  FIG. 3A  in the second configuration; 
         FIG. 4A  shows a cross-sectional view of a further example of a holder for a beverage container, having an internal shoulder for supporting a beverage container; 
         FIG. 4B  shows the cross-sectional view of  FIG. 4A  with an alternate beverage container received in the cavity; 
         FIG. 5  shows a perspective view of a modular holder having a variety of replaceable collar sizes and a plurality of removable inserts; 
         FIGS. 6A to 6C  illustrate a device for holding a variety of sizes of beverage container, shown respectively in perspective view from above, in perspective cutaway view from above, and in perspective view from below; 
         FIG. 7A  shows an exploded view the device of  FIG. 6A  with a removable cap part removed; 
         FIGS. 7B and 7C  show a removable cap, collar, and removable insert respectively in perspective view from above, and in perspective view from below; and 
         FIGS. 8A to 8C  show the device of  FIGS. 6A to 6C and 7A to 7C  with a variety of sizes of beverage containers located in the cavity. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1A and 1B , an example of a holder  100  according to the present disclosure has a generally cylindrical shape. The holder  100  has a side wall  102  and an opening  108  allowing access to an internal cavity  114  (not visible in  FIGS. 1A and 1B ), the opening  108  being best seen in  FIG. 1A . At the other end of the side wall  102  from the opening  108  is a base  104 . The base  104  and the side wall  102  together define and enclose the cavity  114 . The cavity  114  also has a generally cylindrical shape as it conforms to the interior of the cylindrical side wall  102  and the interior of the base  104 . The opening  108  allows access to the cavity  114  and in particular is arranged to allow a user to insert a beverage container (not shown in  FIGS. 1A and 1B ) into the cavity  114 . 
     An adjustable collar  110  is provided in the opening  108 , near to the rim of the side wall  102 . The adjustable collar  110  extends substantially around the opening  108 , meaning that the collar  110  forms a roughly circular shape circumferentially around the internal surface of the side wall  102 . 
     The adjustable collar  110  is shown in a first configuration in which it lies substantially along the interior of the side wall  102 . This arrangement allows beverage containers to be inserted and removed with ease. In order to allow a wide variety of beverage containers to be inserted into the cavity, the cavity  114 , the opening  108  and the collar  110  (in the first configuration) should be provided to be large enough to allow the beverage container to be inserted with ease. For example, this may mean that the opening  108 , collar  110 , and cavity all have an internal diameter which is at least as large as the beverage container, and preferably also have an annular clearance of at least 1 mm to 2 mm around the outer surface of the beverage container, to ensure that the user can easily insert and remove the beverage container. While the variety of beverage containers is in theory unlimited, in practice there is a degree of standardisation in the industry. The table below illustrates the dimensions of the most common containers. Based on this table, the collar  110  may be provided to be at least 73 mm, or at least 75 mm with clearance, in the first configuration. The second configuration (discussed in detail below) is one in which the collar  110  contacts the exterior surface of a beverage container. Based on the below table, this should be set to approximately the diameter of the container in question, or possibly a little smaller (1 mm to 2 mm smaller in diameter) than the container diameter to allow a degree of gripping. Again, noting the values in the table, the smallest container would imply a collar  110  diameter of 53.3 mm or around 51 mm if a gripping effect is to be provided. In some cases, the first configuration of the collar  110  may be just wide enough to contact or grip the largest beverage container. That is, in the first configuration, there may be no clearance between the outer surface of a particular beverage container and the collar  110 . 
     
       
         
           
               
               
               
               
               
             
               
                   
                   
               
               
                   
                 Name 
                 Height 
                 Body diameter 
                 Volume 
               
               
                   
                   
               
             
            
               
                   
                 Traditional Can 
                 115.2 mm 
                 66.2 mm 
                 330 ml 
               
               
                   
                 Traditional Can 
                 149.9 mm 
                 66.2 mm 
                 440 ml 
               
               
                   
                 Traditional Can 
                   168 mm 
                 66.2 mm 
                 500 ml 
               
               
                   
                 Traditional Can 
                 188.1 mm 
                 66.2 mm 
                 568 ml 
               
               
                   
                 Sleek Can 
                 113.9 mm 
                 58.1 mm 
                 250 ml 
               
               
                   
                 Sleek Can 
                 145.4 mm 
                 58.1 mm 
                 330 ml 
               
               
                   
                 Sleek Can 
                 156.9 mm 
                 57.6 mm 
                 355 ml 
               
               
                   
                 Sleek Can 
                 152.1 mm 
                 63.5 mm 
                 400 ml 
               
               
                   
                 Sleek Can 
                   168 mm 
                 63.5 mm 
                 450 ml 
               
               
                   
                 Sleek Can 
                 173.5 mm 
                 63.5 mm 
                 473 ml 
               
               
                   
                 Sleek Can 
                 193.7 mm 
                 66.2 mm 
                 591 ml 
               
               
                   
                 Slim Can 
                  88.5 mm 
                 53.3 mm 
                 150 ml 
               
               
                   
                 Slim Can 
                 111.2 mm 
                 53.3 mm 
                 200 ml 
               
               
                   
                 Slim Can 
                   134 mm 
                 53.3 mm 
                 250 ml 
               
               
                   
                 Standard Bottle 
                   218 mm 
                 55.0 mm 
                 275 ml 
               
               
                   
                 Standard Bottle 
                 226.9 mm 
                 60.7 mm 
                 330 ml 
               
               
                   
                 Vichy Amber Bottle 
                   227 mm 
                 60.8 mm 
                 330 ml 
               
               
                   
                 Belgian Bottle 
                 246.5 mm 
                 69.0 mm 
                 500 ml 
               
               
                   
                 Standard Bottle 
                 246.5 mm 
                 69.0 mm 
                 500 ml 
               
               
                   
                 Real Ale 
                 224.8 mm 
                 73.0 mm 
                 500 ml 
               
               
                   
                 Bottle 
                   227 mm 
                 59.3 mm 
                 330 ml 
               
               
                   
                 Bottle 
                   231 mm 
                 59.3 mm 
                 330 ml 
               
               
                   
                 Bottle 
                   214 mm 
                 56.1 mm 
                 275 ml 
               
               
                   
                 Bottle 
                   215 mm 
                 60.6 mm 
                 330 ml 
               
               
                   
                 Bottle 
                   198 mm 
                 64.1 mm 
                 355 ml 
               
               
                   
                 Bottle 
                 221.4 mm 
                 57.5 mm 
                 300 ml 
               
               
                   
                   
               
            
           
         
       
     
     The height column provides guidance for the height dimension of the internal cavity  114  (that is, the length of the side wall  102  between the base  104  and the opening  108 ). Generally, the collar  110  should be spaced apart from the internal surface of the base  104  by a distance which is shorter than the height of the beverage container intended to be received in the cavity  114 . This allows the beverage container to protrude out of the top of the holder  100  which in turn can aid a user in drinking from the beverage container. For beverage holders which are cans, the protrusion may be only around 5 mm to 10 mm. For beverage holders which are bottles, the protrusion is usually somewhat larger than this as it is usually for the entire neck of the bottle to protrude. For bottles therefore, the protrusion may be closer to about 50 mm to 100 mm, depending on the exact bottle design. In any event, the table above, illustrating a small subset of the sizes of bottles and cans available on the market underscores the need for a single holder adapted to receive multiple sizes of container. 
     In some cases, in order to accommodate a wide range of beverage container types in a single holder, the collar  110  may be provided on a removable and replaceable cap, with a series of such caps being used to provide collars  110  of different maximum and minimum diameters (in the first and second configurations respectively). In addition, the caps may have a different height from one another, to allow the collar  110  to align correctly with the top regions of the intended beverage container. That is the cap may be used to space the collar  110  a desired distance from the base  102 . 
     As noted below, the collar  110  may be adapted to operate with only a subset of container sizes. In this case, the collar  110  may have a diameter in each of the first and second configurations which lies in the range 50 mm to 75 mm (with the diameter in the second configuration having a smaller diameter than the diameter of the first configuration), without necessarily spanning the entirety of the 50 mm to 75 mm range. The dimensions provided in the above table are relevant for various aspects of the following discussion and should therefore be borne in mind in understanding and interpreting the principles of operation of the holder  100 . 
     As can be seen in  FIG. 1B , which shows the holder  100  from below, a bottle opener  106  is provided mounted to the exterior of the base  104 . This can allow a user to open bottles prior to inserting the bottle into the cavity  114 . 
     The base  104  and the side wall  102  are formed from any suitable material, that is one which is rigid and durable enough to withstand repeated use as set out herein. Examples of suitable materials include steels as well as various plastics. In some cases, the base  104  and/or the side wall  102  is/are hollow and include insulating means, such as vacuum, aerogel, fibrous materials, or other insulating materials. 
     The exterior surface of the side wall  102  is provided with ergonomic grips  112  to assist a user in holding the holder  100  firmly, but comfortably. The grips may take the form of indents, textured, rough, or roughened material, for example, depending on the specific embodiment. 
     Turning now to  FIGS. 2A to 2D , in which the process of inserting a beverage container  116  into the cavity  114  of the holder  100  in cross-sectional elevation view.  FIG. 2A  shows a cross-sectional view of a holder  100  of the type shown in  FIGS. 1A and 1B , prior to a beverage container  116  being inserted into the cavity  114 . Due to this overlap, features already described above will not be described in detail again. In  FIG. 2A , the collar  110  is in a first configuration, lying substantially flat against the interior of the side wall  102 , and providing little or no obstruction of the opening  108 . 
     In  FIG. 2B  a beverage container  116  has been inserted into the cavity  114 , occupying much of the internal volume of the holder  100 . As can be seen, the width of the beverage container  116  is less than the diameter of the opening  108  meaning that the container easily fits through the opening  108  to enter the cavity  114 . Moreover, the height of the cavity (i.e. distance between the internal surface of the base  104  and the rim of the side wall  102 ) is selected to ensure that the collar  110  aligns with a desired portion of the beverage container  116 . In the example shown in  FIG. 2B  the beverage container  116  is a bottle, and the collar  110  aligns with the bottle near the neck of the bottle. The neck of the bottle extends out from the opening  108  (i.e. beyond the side wall  102 ) in order to provide a more comfortable drinking experience for a user., although this is not essential in all examples. 
     Since the bottle  116  is narrower than the opening  108 , the collar  110  has been adjusted in  FIG. 2B , causing the collar to restrict its central aperture  111  (see  FIG. 3 ), otherwise referred to as the second configuration. A central portion (central in an axial direction, i.e. approximately halfway up the collar  110 ) of the collar  110  to flex inwardly and contact the bottle  116 . This adjustment can be made at any time in the process of inserting a beverage container  116  into the cavity  114 . For example, it may be that a user prefers to adjust the collar  110  prior to inserting the beverage container  116 , or that they prefer to ensure that the beverage container  116  is correctly seated in the cavity  114  prior to tightening the collar  110  to contact the beverage container  116 . Once the user has finished drinking from the beverage container  116 , i.e. the beverage container is empty  116 , the user can remove the beverage container  116  and replace it with a full beverage container  116 , if desired. 
     Where the new beverage container is the same shape and size as the previous beverage container  116 , the previous beverage container  116  may be removed without adjusting the collar  110  at all. Similarly, the new beverage container  116  may be inserted into the cavity without adjusting the collar  110 , leading to a very quick and simple process. Of course, a user may elect to loosen the collar  110  (i.e. transition from the second configuration back to the first configuration) to assist in either removal of the old beverage container  116  or insertion of the new one. 
     In cases where the new beverage container  116  is a different shape or size, the user will need to adjust the collar  110  to cause the collar  110  to contact the beverage container  116 . 
     As above, this adjustment can be made at any point in the process which the user finds convenient. 
     As shown, the adjustable collar  110  comprises a strip of flexible material. As can be seen, the collar  110  is engaged with an actuator  118  located above the collar  110  (here “above” means close to the rim of the side wall  102 , or further from the base  104 ). In this example the actuator  118  takes the form of an annular element which engages with the opening  108  using cooperating screw threads. Rotating the actuator  118  relative to the side wall  102  engages the cooperating screw threads and moves the lower edge of the actuator upwards or downwards depending on the direction of rotation. Here “below” and “lower” mean closer to the base  104 , or further from the rim of the side wall  102 . “Upwards” and “downwards” are to be construed accordingly. 
     Comparing  FIGS. 2A and 2B  with one another reveals two positions of the adjustable collar  110 : substantially flat against the side wall  102  in the first configuration; and bowed outward to contact the beverage container  116  in the second configuration. However, it will be appreciated that the transition between the first and second configurations passes through one or more intermediate configurations in which the collar  110  restricts the opening  108  to diameters smaller than that in its first configuration, yet larger than that in its second configuration. In other words, the transition between the first and second configurations is a continuous one and there exist positions for the actuator  118  which correspond to most, if not all intermediate diameters for the aperture in the collar  110 . Indeed, it will be apparent that in some cases it may be possible to use the actuator  118  to cause the collar  110  to restrict the opening  108  more than it does in  FIG. 2B  (for example to contact a beverage container  116  having a smaller diameter than that shown in  FIG. 2B ). 
     Although not expressly shown, the actuator  118  may have a graduated motion within the continuous transition region. In such cases, there may be one or more positions in which the actuator corresponds to specific diameters of the aperture in the collar  110 . For example, as set out in the table above, it is clear that certain diameters are commonly used, and it would therefore be beneficial to allow a user to set the diameter of the collar  110  to match some or all of these diameters, by using the actuator  118 . In order to assist in this, the actuator  118  may be provided with markings to indicate positions of the actuator  118  which correspond to particular diameters of the collar  110 . 
     Additionally, or alternatively, the motion of the actuator  118  may be locally stable at particular intermediate positions (corresponding to common aperture diameters), by using detents or the like to allow a user to stably maintain a desired intermediate position of the actuator  118 . 
     Additionally, or alternatively, the motion of the actuator  118  may be arranged in each of a free mode and a locked mode. In the free mode, the actuator  118  can freely move to change the diameter of the aperture of the collar  110 . Once the desired level of constriction of the opening  108  has been achieved, the actuator  118  can be put into the locked mode, in which it is prevented from moving (and correspondingly the diameter of the collar  110  is also fixed). The diameter of the collar  110  can be changed again by returning the actuator  118  to the free mode and adjusting the collar  110  using the actuator  118  in the usual way. 
     The first and second configurations may also make use of any of the above means for retaining the actuator  118  and the collar  110  in position and/or notifying a user as to the current diameter of the aperture in the collar  110 . 
     It will be apparent that the collar  110  is held in position relative to the side wall  102 , and consequently the actuator  118  deforms the collar  110 , but the collar  110  remains its angular alignment with the side wall  102 . In other words, the actuator  118  does not drag the collar  110  around as the actuator  118  moves downward, thereby preventing the collar from becoming twisted and possibly damaged. 
     In other examples, the collar  110  may be fixed to the actuator  118  instead (see e.g.  FIG. 5 ), or not fixed to either the actuator  118  or the side wall  102 . In any case, the motion of the actuator  118  does not cause the collar  110  to twist. That is, the upper and lower edges of the collar  110  remain angularly aligned with one another during transitions between configurations of the collar  110 . 
       FIG. 2B  shows an example of a beverage container  116  having been inserted into the cavity  114 . Although not shown in detail, the insertion process involves orienting the beverage container  116  with its base (the portion intended to rest against the internal surface of the base  104  of the holder  100 ) oriented towards the base  104  of the holder  100 . The beverage container  116  can then be passed through the opening  108  and past the collar  110  until it occupies the cavity  114  and contacts the base  104 . In this way, the beverage container  116  can be inserted into the holder  100  without undue effort on the part of the user. 
     In  FIG. 2B  the beverage container  116  is a bottle. It is worth noting that due to the shape of bottles having most of their volume located towards their base, the location at which the collar  110  contacts the exterior surface of the bottle is at the uppermost part of the body, sometimes referred to as the shoulder of the bottle. Since most of the volume of the beverage is located below the comparatively thinner neck of the bottle, contacting the beverage container  116  at the shoulder of the bottle ensures that most of the beverage is located below the collar  110  and benefits from any insulating effect, even when the bottle is full. As will be seen below, the situation is slightly different for other beverage containers  116  such as cans. 
     In  FIGS. 2C and 2D , a beverage container  116  in the form of a can is shown in the cavity  114 . A small part of the of the can extends out from the opening  108  (i.e. beyond the side wall  102 ) in order to provide a more comfortable drinking experience for a user, although this is not essential in all examples. 
     It can be seen by comparing  FIGS. 2C and 2D  that the actuator  118  forces the adjustable collar  110  away from the side wall  102  towards the centre of the cavity  114 . In other words, the actuator  118  is movable relative to the side wall  102  and can be used to cause the adjustable collar  110  to transition between the first and second configurations. In the second configuration the collar  110  constricts the opening  108 . As can be seen in  FIG. 2C , the collar  110  constricts the opening  108  to the extent that the collar  110  contacts the external surface of the beverage container  116 . Note that in  FIG. 2C , the collar  110  has an aperture size between that shown in  FIG. 2B  (the second configuration) and that shown in  FIGS. 2A and 2D  (the first configuration). This is sometimes referred to as an intermediate configuration. 
       FIGS. 2C and 2D  respectively illustrate the beginning and end of the process of the actuator  118  moving and causing the collar  110  to transition between the intermediate configuration in  FIG. 2C , and the first configuration in  FIG. 2D . More specifically,  FIG. 2C  shows a central portion of the collar  110  flexing into the cavity  114  to contact a beverage container  116  (in this case a can), resulting in the collar  110  having a noticeably C-shaped profile. In  FIG. 2D  the collar  110  lies substantially against an internal surface of the side wall  102 . 
     Of course, while an actuator  118  is shown which is rotated by a user to actuate the adjustable collar  110  to cause a vertical motion, other actuators will be apparent which use only vertical or rotational motion to actuate the collar  110 . 
     As the lower edge of the actuator  118  moves downward, it is arranged to engage the upper edge of the adjustable collar  110 . It can be seen that the collar  110  is unable to move vertically (or axially) relative to the side wall  102  because the collar  110  is supported from below by a circumferential protrusion  120 . The action of the actuator  118  moving downward presses the collar  110  against the circumferential protrusion  120  and causes it to bend inwardly towards the centre of the cavity  114 . 
     In  FIG. 2C , a seal is formed at least part way around the outer surface of the beverage container  116 . This helps to insulate the container  116  (and its contents) by reducing heat flow into or out of the cavity  114 . The act of forming a seal may also serve to grip the container  116  and thereby assist in retaining the container  116  in the cavity  114 . 
     More specifically the adjustable collar  110  lies substantially along an internal wall of the side wall  102  in the first configuration and as shown a central portion of the adjustable collar  110  is deflected away from the internal wall in the intermediate and second configurations. This arrangement results in the intermediate and second configurations having a pair of opposed edges of the collar  110  running circumferentially around the interior surface of the side wall  102  with a central portion of the collar  110  bowing inwardly into the cavity  114 . This results in a double layer of the collar  110  being present between the cavity  114  and the outside environment. This in turn can lead to an improved insulating effect in terms of reducing conductive, convective, and radiative heat transfers between the cavity  114  and the outside environment. In other examples, only one edge of the collar  110  may be retained against the interior surface of the side wall  102 . This advantageously allows a collar  110  of a given size to have a wider range of aperture diameters accessible to it, as the collar  110  is not doubled up in the second configuration, so can extend broadly twice as far towards the centre of the cavity  114 . 
     When the beverage has been fully consumed, the steps above can be reversed to release the beverage container  116 , thereby allowing its removal. 
     Turning now to  FIG. 3 , which shows an example of a collar  110  according to the present disclosure separated from the holder  100 . The collar  100  is presented in both the first and second configurations to illustrate the differences between the configurations. 
     As noted above, the collar  110  is formed as a strip of flexible material. More specifically, the collar  110  is a strip joined at its ends to form a loop of flexible material, arranged to conform to the inner surface of the side wall  102 . In the first configuration, shown at the top of the Figure, the collar  110  has a form which deviates only slightly from that of a straight-sided cylinder. More specifically, the collar  110  has a central portion (central in the axial direction, i.e. approximately half way up the collar  110 ) which bows slightly toward the central aperture  111 . This slight inward bowing of the central portion helps to encourage the collar  110  to flex in the correct direction and manner when the upper and lower edges are squeezed between an actuator  118  and a circumferential support surface  120 . 
     In the second configuration, shown at the bottom of the Figure, the collar has been pressed vertically by the actuator  118  (not shown) forcing the upper and lower edges of the collar  110  towards one another and causing a central portion of the collar  110  to bow inwardly towards the centre of the central aperture  111 . In the second configuration, the collar  110  has the form a section of the innermost part of a torus. 
     The collar  110  may be formed of any suitable pliant material. For example, rubbers, elastic materials, or elastomers may all be used. In addition, the adjustable collar  110  may be provided with a rough or roughened surface for gripping the beverage container  116  when the adjustable collar is in the second configuration. 
     As shown in  FIGS. 3A and 3B , the collar  110  has one or more recessed features  122  formed in its innermost surface. These features  122  may be indents, creases or perforations passing entirely through the collar  110 . The purpose of these features  122  is to allow or even encourage the collar  110  to constrict its inner aperture  111  in the desired manner. It will be appreciated that the central portion of the collar  110 , which forms the innermost edge of the collar  110  in the second configuration, undergoes compression during the transition to (and while in) the second configuration. In order to prevent damage to the collar  110  in these circumstances, the collar  110  is provided with the recessed features  122  described above to ease the strain of contracting in this way. 
     As noted above, some examples of collars  110  may retain only one edge around the circumference of the opening  108  with the other edge forming the innermost portion. In such cases, the recessed features  122  may be located along the edge which is deflected towards the centre of the cavity  114 , since this is the area which will experience the greatest compressive strain. In any case, the deformation to the second configuration tends to cause at least some parts of the collar  110  to undergo strain (e.g. compressive or tensile strain). This strain in turn biases the collar  110  towards the first configuration. This means that the collar  110  tends to spring back to the first configuration when a load is removed—e.g. when the actuator  118  is moved such that the actuator  118  no longer presses the collar  110  against the circumferential support  120  within the cavity  114 . 
     Another effect of the recessed features  122  may be to provide a discontinuous seal around the external surface of the beverage container  116 , for example to allow air pressure equalisation. 
     Turning now to  FIGS. 4A and 4B , a further example of a holder  100  of the present disclosure is shown. The operation of the holder  100  with regard to the insertion of a beverage container  116 , adjusting the collar  110 , and removing the beverage container  116  occur broadly as set out above, and will not be discussed again in detail. 
     As can be seen, the holder  100  has an internal shoulder  124  arranged to provide support to beverage containers  116  exceeding a particular diameter at their base. For example,  FIG. 4A  shows a relatively short and wide beverage container  116  inserted into the holder  100 . As can be seen the shoulder  124  provides support to the beverage container  116 , spaced away from the internal surface of the base  104 . The support raises the beverage container  116  so that the collar  110  aligns with the upper edge of the beverage container  116 . If no shoulder  124  were present, the beverage container could in some cases be too short to align with the collar  110  at all. 
       FIG. 4B  shows a different beverage container  116  located within the cavity  114 . The beverage container  116  in  FIG. 4B  is both taller and narrower than the beverage container  116  in  FIG. 4A . In fact, the beverage container  116  in  FIG. 4B  is narrow enough that it fits into the gap between the shoulder  124  and contacts the internal surface of the base  104 . This arrangement allows the relatively taller, but narrower, beverage container  116  to also be aligned with the collar  110 . It will be apparent that the height of the shoulder  124  and the diameter of the gap between the supporting edge portions of the shoulder  124  can be selected to accommodate various standard sizes of bottles and cans, based on the table above. 
     In some cases, it may be possible to have a stepped internal arrangement in which a series of shoulders  124  are provided inside the cavity  114 . The highest shoulder  124  would have the widest central gap and would be provided to support the base of the widest and shortest type of beverage container  116 . The next shoulder  124  would have a less wide gap and would extend less far up the side wall  102  from the base  104  than the highest shoulder  124 . This would support a beverage container  116  of intermediate width and intermediate height. As many shoulders  124  as desired could be included to accommodate beverage holders  116  which are progressively narrower and taller, with the narrowest and tallest beverage holder  116  resting on the internal surface of the base  104 . In this way, a single holder  100  can be provided with the means to receive a wide range of different types of beverage container  116 , and provide correct alignment between the collar  110  and each of the different types of beverage container  116 , by carefully selecting the dimensions of the shoulders  124  carefully. 
     In some cases, a series of removable and replaceable shoulders  124  may be provided in order to allow a user to tailor the holder  100  to their preferred shape of beverage container  116 . Advantageously, such removable shoulders  124  may include a material for cooling and/or heating the interior of the cavity  114 . For example, phase change materials or materials with high heat capacity can be placed in a freezer or oven to cool or heat them. These materials can be placed in the cavity  114  to help maintain the cavity  114  (and thereby the beverage) at a reduced or elevated temperature. 
     In fact, the holder  100  may be provided with such materials in contact with the interior of the cavity  114  without aiming to provide the effect provided by the shoulders  124  at all. 
     Finally, turning to  FIG. 5 , a modular holder system is shown, which includes a holder  100  and a series of inserts  126  containing a material for cooling and/or heating the interior of the cavity  114 , a series of replaceable shoulders  124  and a series of replaceable caps  128  having a collar  110  mounted on each of the caps  128 . 
     The caps each have an actuator  118  and an opening  108 . The openings  108 , the height of each cap  128 , and the distance below the opening  108  and the collar  110  can be varied for each replaceable cap  128  to provide a great degree of flexibility to a user in adapting their holder  100  to the types of beverage container  116  which they wish to drink from. 
     Similarly, the shoulders  124  can be provided with a range of internal diameters and heights to allow a user to adapt the cavity  114  to a variety of different beverage containers  116 . The inserts  126  serve a dual purpose of spacing a beverage container  116  away from the base  104  and of providing cooling and/or heating to the cavity  114 . A plurality of such inserts  126  may be provided so that e.g. a user can keep several in their freezer and replace the inserts  126  as they warm up with fresh, cool ones. 
     The user is thereby provided with a large amount of flexibility in assembling a holder  100  tailored to their specific needs. While this kit of parts is shown with a large number of options, it will be appreciated that a kit of parts may include just the holder  100  with two interchangeable modules of any type. 
     Consider now  FIGS. 6A to 6C , which show an alternative device  200  for holding a beverage container (not shown).  FIG. 6A  shows the device  200  in perspective view from above,  FIG. 6B  shows broadly the same view as  FIG. 6A , but in cutaway to illustrate the internal features, and  FIG. 6C  shows the device  200  in perspective view from below. Many features of the device  200  are similar to the holder  100  discussed at length above, and will not be discussed in detail again for conciseness. 
     The device  200  has a base  204  and a side wall  202 , collectively defining a cavity  214 . The cavity  214  is accessible through an opening  208  located at a rim of the side wall  202  and spaced apart from the base  204  by the length of the side wall  202 . Inside the cavity  214  between the opening  208  and the base  204  is a pliable collar  210  formed from a flexible and deformable material. The collar  210  has an aperture  212  which encircles a central axis of the cavity (the central axis is indicated as a broken vertical line in  FIG. 6A ). The collar  210  may be made of any suitable material, but silicone rubbers having a hardness of between about 40 and 50 (e.g. about 55) on the Shore durometer A scale have been found to work at thicknesses of between about 1 mm and 3 mm. These materials are also suitable for providing a gripping effect whereby the collar  210  grips beverage containers inserted through the aperture  212 . The gripping effect may be increased by providing a roughened or textured surface to the collar  210  (or at least to the parts of the collar  210  intended to grip the beverage container). 
     In use (and as shown in more detail in  FIGS. 8A to 8C ), a beverage container is insertable through the opening  208  and into the cavity  214 . In doing so, the beverage container must also pass through the aperture  212  in the collar  210 . In response to this the collar  210  deforms so that an inner edge  220  of the collar  210  (the portion of the collar  210  which defines the aperture  212 ) deforms to grip an outer surface of the beverage container. It can be seen that the aperture  212  is less wide than the opening  208 . This has the effect that the opening  208  sets an upper limit on the size of beverage container which can be inserted into the cavity  214  and the aperture  212  sets a lower limit on beverage container size, below which the collar  210  will not contact or grip the beverage container with the desired force (or at all, depending on the size of the container). Of course, the ratio of the width of the aperture  212  to the width of the opening  208  can be adjusted downwards (e.g. making the aperture  212  smaller), in order to increase the range of containers which can be suitably held by the device  200 . 
     In the present example the width of the aperture  212  is about 44.6 mm and the width of the opening  208  is about 73 mm, meaning that the ratio of the width of the aperture  212  to the width of the opening  208  is about 0.61, but it may be smaller than this in some examples, or as large as 0.9 in others. In general, the opening  208  is selected to be large than the largest diameter of beverage container  216  of the ranges of sizes intended to be accommodated by the device  200 . Similarly the aperture  212  is selected, in general, to be smaller than the smallest diameter of beverage container  216  of the ranges of sizes intended to be accommodated by the device  200 . The table set out above listing commonly used sizes may be used as a guide to select the specific sizes of the opening  208  and the aperture  212  for a specific use. For example to provide a device  200  which is specifically adapted to securely accommodate two or more specific sizes of beverage container. Note that the cavity  214  is slightly less wide than the opening  208 —the cavity  214  having a width of about 70 mm. In this example the width of the cavity  214  also plays a role in limiting the maximum size of beverage container receivable in the device  200 , but in some examples the cavity  214  is at least as wide as the opening  208 , in which case it is the opening  208  alone which determines this upper limit. The sizes of the cavity  214 , the aperture  212  and the opening  208  may be selected in accordance with the table above setting out the most common beverage container sizes, or in accordance with other known common sizes of beverage container. 
     In the example shown the device  200 , side wall  202  and cavity  214  are all generally cylindrical, and the collar  210  is annular, having a circular aperture  212 . This is to adapt the device  200  to the usual shape of standard container sizes—also broadly cylindrical—but it will be appreciated that the principles discussed herein could easily be adapted to other shapes of container by adapting the shape of the respective parts of the device  200  accordingly. 
     The collar  210  extends between the aperture  212  towards the side wall  202 . Note that in this example the collar  210  does not extend all the way to the side wall, but has a radially extending portion  222  (radial when undeformed, at least) which, since the collar  210  has an annular shape largely or entirely blocking an outer annulus of the cavity  214 , has the effect of fully or partially sealing the lower part of the cavity from the outside environment when a beverage container is inserted. This radially extending portion  222  of the collar  210  gives the collar a planar and annular shape (lying generally parallel with the base  204 ) and has perforations  218  formed through the collar  210 . These allow a seal to be formed all the way around the beverage container, without causing a complete air tight seal between the cavity  214  and the environment, for example to allow pressure equalisation. In this way, the perforations  218  can be made as small or large as desired to reduce convective heat transfer out of the cavity  214 , while allowing as much pressure equalisation as needed. As shown, there are two perforations  218  each about 3 mm in diameter although different numbers and/or sizes of perforation  218  may be used, depending on the desired application. 
     The collar  210  has a slightly thicker portion at its inner edge  220 . This can help to reduce instances of tearing by providing a more robust portion of the collar  210  at the point which undergoes the most wear and tear (which is also the part which stretches and deforms the most during use). As shown, the inner edge  220  has a generally circular profile in cross-section, although other shapes are possible depending on the desired properties. The inner rounded edge  220  has a radius of curvature of about 1 mm and the collar is about 1 mm thick, meaning that the inner edge  220  is about twice as thick as the other parts of the collar  222 . In general, the thicker the other parts of the collar  222 , the less thickening is required to bolster the inner edge  220 . The thicker part of the collar  210  at the inner edge  220  extends radially outward a first distance from the aperture  212  to the other parts of the collar  222 . The other parts of the collar  222  extend radially outward a second distance to the outer edge of the collar. In this example, the second distance is about 5 times the first distance, but this relationship is dependent on the arrangement of the aperture  212  and its relationship to the size of the opening  208 . This means that the second distance may be between 2 and 10 times the first distance. 
     The side wall  202  is shown as being formed of two thin concentric layers (e.g. stainless steel), with a void therebetween. This void can help to provide thermal insulation to the cavity  214 , for example by filling with insulating material, or even with vacuum. The portion of the side wall just beneath the collar  210  has a shoulder  215   b  formed therein. The shoulder represents a narrowing of the cavity  214  from its width at the opening  208  to its width below the collar  210 . This shoulder  215   b  has a dual role: first to provide space (also called a recess) for the collar  210  to fold back into when a beverage container is inserted (see  FIGS. 8A to 8C  for more detail); and second to allow the total thickness of the side wall  202  to increase between the base  204  and the collar  210 , while allowing the outer surface of the side wall  202  to remain flat (in this case cylindrical). This second feature allows the side wall  202  between the collar  210  and the base  204  to provide the insulating effect discussed above in parts where the insulation is most needed and leads to a compact and ergonomic device. 
     A corresponding feature is seen in the side wall  202  above the collar  210  (that is, between the collar  210  and the open end of the side wall  202 ). Here, recess  215   a  above the collar  210  operates analogously to the space (or recess) formed by the shoulder  215   b,  to provide space for the collar  210  to fold into, except in this example the recess  215  is provided to provide space for the collar  210  to fold into when the beverage container is removed from the device  200 . In such a removal of the beverage container, the collar  210  folds in much the same way as during insertion of the beverage container, but instead of folding downward towards shoulder  215   b  the collar  210  folds upwards into recess  215   a.  In each case, the insertion or removal process is able to be completed with less resistance, and thereby reduces the chances that the user will need to exert excessive force and reduces the chance of injury by making both slippage and accidental crushing of the container less likely. 
     It can be seen that the recess  215   a  is bounded at its upper edge by a circumferential protrusion, but the side wall  202  returns to a wider width above the circumferential protrusion, meaning that the rim of the side wall  202  at its open end is wider than the circumferential protrusion. This can help funnel and centre the beverage container prior to encountering the collar  210 . In other examples, the side wall  202  may not revert to a wider size above the collar  210 , but instead the rim may be the same width as the circumferential protrusion, and the side wall  202  above the collar  210  remains flush. 
     In the example shown, the narrowest portion of the cavity  214  above the collar  210  matches the narrowest width of the cavity  214  below the collar  210 . In fact, as the device  200  and the cavity  214  are generally cylindrical, this simply means that the diameter of the cavity  214  is the same above and below the collar  210 , but the comments here apply to non-cylindrical shapes of cavity  214  as well. This arrangement means that the user can be alerted to whether a given beverage container will fit all the way into the cavity  214 , without needing to push the beverage container through the collar  210 . In some cases, this need not be true, for example in some cases the narrowest portion of the cavity  214  above the collar  210  may be narrower than the narrowest width of the cavity  214  below the collar  210 , to ensure that the largest size of container which can be inserted into the device  200  nevertheless has a little leeway when received in the cavity  214 , thereby allowing for easy insertion and removal of the beverage container. 
     Located in the cavity  214 , adjacent to the base  204  is an insert  224 . The purpose of this is described in more detail below, but broadly this is used to assist a user in correctly positioning the beverage container in the cavity  214 . The device  200  may include material in thermal contact with the interior of the cavity  214  for cooling and/or heating the interior of the cavity  214 . This may be provided for example within a hollow interior of the insert  224   
     The lower end of the device  200  is capped with by the base  204 . As noted elsewhere, this is shown sealed and with a void for filling with insulation, but either or both of these may not be true in other examples. The base  204  has a bottle opener  204  secured in place, which as discussed above can be useful for ensuring that a bottle opener is always to hand. 
     Turning now to  FIGS. 7A to 7C , which show the same device  200  in various exploded views. For conciseness features already described will not be described in detail again. In  FIG. 7A , the device  200  is shown with a removable cap  228  in the process of being removed from the device  200 . Note that even though the cap  228  is removable, the inner surface of the cap  228  acts like a side wall  202 , and consequently, the side wall  202  is intended to refer to the internal surface of the cavity  214  between the open end of the side wall  202  and the base when the device  200  is assembled, and irrespective of whether the cap  228  (with its associated portion of side wall  202 ) is removable. In  FIGS. 7B and 7C  the removable cap  228 , the collar  210  and the removable insert  224  are shown in perspective views from above and below respectively. 
     The upper portion of the device  200  is a removable cap  228 , which allows the collar  210  to be removed, for example so that the insert  224  can be extracted from the cavity  214 . It can be seen that the insert  224  is cup shaped (that is, has a U-shaped profile), meaning that the insert  224  can be easily placed into the cavity  214  either way up (that is in an orientation having a U-shaped profile or one having a ∩-shaped profile). This allows a user to decide whether to provide a platform for the beverage container to rest on (by inserting the insert  224  or not) and also how high that platform should be (by inserting the insert  224  in one of the two orientations discussed above). In the configuration having the U-shaped profile, the beverage container is spaced away from the base  204  by the thickness of the horizontal part of the insert  224 , while in the configuration having the ∩-shaped profile, the beverage container is spaced away from the base  204  by the thickness of the horizontal part of the insert  224  as well as by the height of the side walls of the insert  224 . These three arrangements can help vertically align the beverage container with the collar  210  as discussed in more detail with reference to  FIGS. 8A to 8C . 
     As can be seen in  FIGS. 7B and 7C , the insert  224  has a series of concentric grooves  226  formed in the surfaces which contact the bottom of the beverage container. These grooves  226  assist in preventing the beverage container sliding relative to the insert  224 , where the beverage container is not as wide as the insert  224 . In some examples, the internal surface of the base  204  may also have grooves or other features formed therein, to achieve this purpose when the insert  224  is not present. 
     The collar  210  is provided as a removable element, separable from the removable cap  228 . This can allow different sizes of collar  210  to be provided, and easily changed, without requiring a whole new device  200  or even a whole new removable cap  228 . The collar  210  is removably attachable to the cap  228  by stretching the collar  210  over the lower edge of the cap  228 . The upper portion of the collar  210  includes a radially inward protrusion for interfacing with a groove around the lower edge of the cap  228 , which can help to ensure that the collar  210  is correctly and securely seated on the cap  228 . In other examples, the collar  210  may be permanently affixed to the cap  228 , or even may be connected to the side  202  wall instead (removably or permanently). 
     In  FIGS. 8A to 8C , the device  200  is shown with various different sizes of beverage container  216  received in the cavity  214 , through the aperture  212  in the collar  210 . Although not shown in detail, the insertion process involves orienting the beverage container  216  with its base (the portion intended to rest against the internal surface of the base  204  of the device  200 ) oriented towards the base  204  of the device  200 . The beverage container  216  can then be passed through the opening  208  until it contacts the collar  210 . By pressing the beverage container  216  against the collar  210 , the collar  210  is forced to deform and deflect downwards (towards the base  204 ) and the aperture  212  in the collar stretches to accommodate the beverage container  216 . In doing so, the elastic nature of the collar  210  causes the collar  210  to contact and grip the beverage container  216 , forming a seal. The beverage container  216  may be pressed further downwards, through the collar  210  until the beverage container  216  occupies the cavity  214  and contacts the base  204 . In this way, the beverage container  216  can be inserted into the device  200  without undue effort on the part of the user. 
     In  FIG. 8A  the beverage container  216  is a short can. This is shown resting on the insert  224  which is arranged in the configuration having the ∩-shaped profile, thereby lifting up the bottom of the beverage container  216 , so that the collar  210  engages with the beverage container  216  at an appropriate height. In addition, the beverage container  216  is held at a height above the base  204  such that the upper portion of the beverage container  216  extends outwardly from the opening  208 , thereby allowing a user to easily drink from the beverage container  216 . 
     The collar  210  is shown in its deformed state, pushed downward (towards the base  204 ) into the cavity  214 . The elasticity of the collar  210  urges it back towards its undeformed, planar arrangement. This restoring force causes the inner edge  220  of the collar  210  to contact and grip the beverage container  216 . The side wall  202  has a shoulder  215   b  which provides space for the collar  210  to fold away from the central axis of the cavity  214 . This in turn ensures that the collar  210  does not present an unduly large resistance to the insertion or removal of the beverage container  216 . This gripping effect allows a user to take a drink from the beverage container  216  while holding the device  200 , without risking the beverage container  216  slipping out of the device  200 . It can be seen that the perforations  218 , while deformed downward with the rest of the collar  210 , retain their role of providing a pressure equalisation channel through the collar  210 . Above the collar  210  is a recess  215   a  to allow the collar  210  to fold upwards, in an similar manner, as the beverage container  216  is being removed from the cavity  214 . 
     In  FIG. 8B , a similar situation is seen, except with a beverage container  216  of different dimensions—a bottle which is taller and narrower than the can of  FIG. 8A . The narrower form of this beverage container  216  results in less deformation of the collar  210  in order to fit the beverage container  216  through the aperture  212 . Nevertheless, the pliable nature of the collar  210  means that one single device  200  can adapt to a range of different widths of beverage container  216  which a user may wish to insert into the device  200 . Indeed, it will be appreciated that yet narrower beverage containers  216  may be inserted into the device  200  than the one shown here. 
     In addition, since the beverage container  216  shown in  FIG. 8B  is relatively tall, the insert  224  is inserted in the configuration having the U-shaped profile, to allow the collar  210  to contact the beverage container  216  relatively higher up the bottle (closer to the neck) than it would if the insert  224  were inserted in the configuration having the ∩-shaped profile. This allows a user to ensure that a greater proportion of taller beverage containers  216  is housed within the cavity  214 , between the collar  210  and the base  204 . This helps to keep the beverage at the desired temperature. In addition, since the beverage container  216  is relatively narrow, the vertical walls of the insert  224  may act to hold the beverage container  216  spaced away from the side wall. This helps prevent the beverage container  216  from rattling around inside the cavity. As noted above, grooves  226  may be provided on the base  204  or the insert  224  which can also help to achieve this effect. 
     Finally,  FIG. 8C  shows a third type of beverage container  216 , having the form of a tall can. This beverage container  216  is tall enough that it can rest on the base  204 , with no need for the insert  224 , since even resting on the base  204 , the collar  210  interfaces with the beverage container  216  at an appropriate height, and the beverage container is tall enough to protrude out of the top of the device  200 . The width of this beverage container  216  is approximately the same as the can shown in  FIG. 8A , so similar comments apply as set out in respect of the operation of the collar  210 . It will be appreciated that the beverage containers  216  in  FIGS. 8A and 8C  do not quite fully occupy the width of the opening  208  or the cavity  214 . This indicates that yet wider beverage containers  216  could be inserted into the device  200 , with a corresponding greater deformation of the collar  210 . 
     As with other examples, the device  200  may be supplied as a kit of parts, including a main body (e.g. side wall  202  and base  204 ); one or more removable caps  228 ; one or more replaceable collars  210 ; and one or more removable inserts  224 , to allow a user to customise their device  200  to their intended uses. 
     The present disclosure also extends to the following numbered clauses: 
     1. A holder for a beverage container, the holder comprising:
         a base;       

     a side wall defining an opening through which the beverage container is insertable; and 
     a collar located within the opening; wherein 
     the side wall and the base together define a cavity for receiving the beverage container; and wherein 
     the collar is adjustable between a first configuration for contacting a first size of beverage container and a second configuration for contacting a second size of beverage container. 
     2. The holder according to clause 1, further comprising an actuator movable relative to the side wall arranged to cause the collar to transition between the first configuration and the second configuration. 
     3. The holder according to clause 2, wherein the actuator is movable relative to the side wall in a rotational and/or an axial direction. 
     4. The holder according to clause 3, wherein motion of the actuator causes the collar to transition continuously between the first and second configurations. 
     5. The holder according to clause 3 or clause 4, wherein motion of the actuator is graduated and wherein the graduated motion corresponds to one or more intermediate configurations of the collar between the first and second configurations. 
     6. The holder according to any one of clauses 3 to 5, wherein the actuator is selectively lockable at least one position, the at least one position corresponding to the first configuration, the second configuration or to an intermediate configuration of the collar. 
     7. The holder according to any one of clauses 2 to 6, wherein the collar retains its angular position relative to the side wall during transitions between the first and second configurations. 
     8. The holder according to any one of the preceding clauses wherein the collar is circular. 
     9. The holder according to any one of the preceding clauses wherein, in each of the first and second configurations, the collar has an internal dimension of between 50 mm and 75 mm at its widest part. 
     10. The holder according to any preceding clause, wherein the collar is provided on a replaceable cap. 
     11. The holder according to clause 10, further comprising a plurality of replaceable caps, each cap having a differently sized collar. 
     12. The holder according to any one of the preceding clauses, wherein the collar comprises a strip of flexible material. 
     13. The holder according to clause 12, wherein the collar lies substantially along an internal wall of the cavity in the first configuration and wherein a portion of the collar is deflected away from an internal surface of the side wall in the second configuration. 
     14. The holder according to clause 12 or clause 13 wherein, in the second configuration, a pair of opposed edges of the strip remain adjacent to the internal wall and an intermediate portion of the strip curves away from an internal surface of the side wall. 
     15. The holder according to any one of clauses 12 to 14, wherein the collar includes one or more indents, creases or perforations. 
     16. The holder according to any one of the preceding clauses, wherein the collar has a rough or roughened surface for gripping the beverage container. 
     17. The holder according to any one of the preceding clauses, wherein the collar extends substantially around an internal surface of the side wall. 
     18. The holder according to any one of the preceding clauses wherein the collar is arranged to form a seal at least part way around an outer surface of the beverage container. 
     19. The holder according to any one of the preceding clauses, wherein the interior of the cavity has a shoulder arranged to contact a base of the beverage container. 
     20. The holder according to any one of the preceding clauses, wherein the collar comprises a plastic or rubber material. 
     21. The holder according to any one of the preceding clauses, wherein the side wall and/or the base comprise(s) rigid plastic and/or metal. 
     22. The holder according to any one of the preceding clauses, wherein the base and/or the side wall is/are hollow and include insulating means. 
     23. The holder according to any one of the preceding clauses, further including a material in thermal contact with the interior of the cavity for cooling and/or heating the interior of the cavity. 
     24. The holder according to any one of the preceding clauses, further including a bottle opener mounted in an exterior surface of the base. 
     25. The holder according to any one of the preceding clauses, further comprising ergonomic grips on an exterior surface of the side wall. 
     26. A device adapted to hold a beverage container having any size within a range of sizes, the device comprising:
         a base;       

     a side wall extending away from the base and defining an opening through which the beverage container is receivable into a cavity defined by the base and the side wall; and 
     a pliable collar spaced away from the base and located within the cavity, the collar extending inwardly into the cavity and having an aperture through which the beverage container is insertable such that the collar deforms to cause an inner edge of the aperture to contact and grip the beverage container; wherein 
     the opening has a first width, the aperture of the collar has a second width, the second width being smaller than the first width and wherein the ratio of the second width to the first width is less than or equal to 0.9. 
     27. The device of clause 26, wherein the collar has a generally planar form. 
     28. The device of clause 27, wherein the plane of the collar is generally parallel with the base. 
     29. The device of any one of the preceding clauses, wherein the inner edge of the collar is thicker than parts of the collar closer to the side wall. 
     30. The device of any one of the preceding clauses, wherein the collar extends generally perpendicularly inwardly from the side wall. 
     31. The device of any one of the preceding clauses, wherein the collar includes one or more perforations extending through the collar. 
     32. The device of any one of the preceding clauses, wherein the collar extends substantially around an internal surface of the side wall. 
     33. The device of any one of the preceding clauses, wherein the collar is arranged to form a seal at least part way around an outer surface of the beverage container, optionally wherein the collar is arranged to form a seal all the way around an outer surface of the beverage container. 
     34. The device of any one of the preceding clauses, wherein the cavity and the aperture have the same general shape as one another, when viewed in the direction of insertion of the beverage container, optionally wherein the cavity is cylindrical and the collar is annular. 
     35. The device of any one of the preceding clauses, wherein the width of the aperture is less than 50 mm, optionally wherein the width of the aperture is greater than 40 mm, optionally wherein the width of the aperture is about 45 mm. 
     36. The device of any one of the preceding clauses, wherein the width of the opening is greater than 55 mm, optionally wherein the width of the opening is at least 70 mm, optionally wherein the width of the opening is about 73 mm. 
     37. The device of any one of the preceding clauses, further including a removable insert insertable into the cavity prior to the beverage container being received in the cavity, to contact a lower end of the beverage container and space the beverage container away from the base. 
     38. The device of clause 37, wherein the insert is U-shaped in profile to selectively allow insertion in two orientations, each orientation spacing the lower end of the beverage container a different distance from the base. 
     39. The device of clause 38, wherein the vertical walls of the U-shaped section are arranged to hold the beverage container centrally within the cavity. 
     40. The device of any one of clauses 37 to 39, wherein the insert has grooves in at least one surface for interfacing with the lower end of the beverage container. 
     41. The holder according to any preceding clause, wherein the collar is provided on a replaceable cap. 
     42. The holder according to clause 41, further comprising a plurality of replaceable caps, each cap having a collar of different widths. 
     43. The holder according to any one of the preceding clauses, wherein the collar has a rough or roughened surface for gripping the beverage container. 
     44. The holder according to any one of the preceding clauses, wherein the collar comprises a plastic or rubber material. 
     45. The holder according to any one of the preceding clauses, wherein the collar has a Shore durometer hardness of 25 Shore A to 90 Shore A, preferably between 40 Shore A and 70 Shore A, preferably about 50 Shore A. 
     46. The holder according to any one of the preceding clauses, wherein an internal surface of the side wall has an internal shoulder or protrusion to provide a recess for receiving the collar as the collar deforms as the beverage container is inserted or removed through the aperture into the cavity. 
     47. The holder according to any one of the preceding clauses, wherein the side wall and/or the base comprise(s) rigid plastic and/or metal. 
     48. The holder according to any one of the preceding clauses, wherein the base and/or the side wall is/are hollow and include insulating means. 
     49. The holder according to any one of the preceding clauses, further including a material in thermal contact with the interior of the cavity for cooling and/or heating the interior of the cavity. 
     50. The holder according to any one of the preceding clauses, further including a bottle opener mounted in an exterior surface of the base.