A portable heating device Field of the Invention

[0001] The present invention relates to a portable heating device, and in particular, though not limited to a portable heating device provided, for example, in the form of a portable soldering iron, a portable hot air blower, a portable heated knife, and the like. Background to the Invention

[0002] Soldering irons are known. They typically comprise a continuous elongate body with an insulating handle at a proximal end and a distal heating tip at a distal end. The tip is used to apply heat to melt solder and for application thereof and the device is manoeuvred by manually gripping the insulating handle. An electrical heating element may be provided. An alternative is a gas or battery device where the heat is provided respectively by gas combustion or battery power. One of the issues that arises with conventional soldering irons is the visibility of the tip when in use. A user can find it difficult to position the device for accurate soldering. Summary of the Invention

[0003] According to the invention there is provided a portable heating device comprising an elongated handle extending between a proximal end and a distal end, and adapted to be gripped by hand between a thumb and at least one finger thereof with the distal end extending in a direction outwardly from the tip of at least one of the gripping fingers, an elongated working element extending between a proximal end and a distal end, the working element being mounted on the handle adjacent the distal end of the handle and being angled relative to the handle. This allows for better viewing of the point being heated, for example an item being soldered in place, because the handle does not obscure the working element from the point of view of a user of the device.

[0004] In one embodiment of the invention the working element is mounted on the handle adjacent the proximal end of the working element. This allows for a compact arrangement and for even better visibility of the working element. [0005] In another embodiment of the invention the handle and the working element when viewed in elevation from a first direction in which an angle defined between the working element and the handle about the distal end of the handle is at a maximum value, the said angle is an obtuse angle, and preferably, the said obtuse angle lies in the range of 94° to 171 °, and advantageously, the said obtuse angle lies in the range of 137° to 167°, and ideally, the said obtuse angle is approximately 152°. Such an angle allows for a very comfortable grip as it allows a very natural position of the hand during use. It also optimises the view of the user of the working implement. [0006] In another embodiment of the invention the handle defines a longitudinally extending primary axis, and the working element extends a longitudinally extending secondary axis, the primary and secondary axes defining the obtuse angle between the handle and the working element when the device is viewed in elevation from the first direction.

[0007] In a further embodiment of the invention the device when viewed in plan from a second direction orthogonal to the first direction, the primary axis and the secondary axis are contained in respective planes, which preferably extend parallel to each other, and ideally, coincide with each other.

[0008] In a further embodiment of the invention the working element is mounted on the handle by a mounting element extending between the distal end of the handle and the working element. This allows a distance between the handle and the working implement which in turn makes the working implement more visible.

[0009] In another embodiment of the invention the perpendicular distance from the secondary axis to the primary axis adjacent the distal end of the handle lies in the range of 5mm to 25mm, and preferably, the perpendicular distance from the secondary axis to the primary axis adjacent the distal end of the handle lies in the range of 10mm to 20mm, and advantageously, the perpendicular distance from the secondary axis to the primary axis adjacent the distal end of the handle is approximately 15mm. [0010] In another embodiment of the invention the working element comprises a heat conductive member adjacent the distal end thereof, and in one embodiment of the invention the heat conductive member is configured as a soldering tool bit. In another embodiment of the invention the heat conductive member is configured as a knife, which preferably comprises an elongated blade extending longitudinally along the heat conductive member. This allows for alternative uses of a heating device of the invention.

[0011] In another embodiment of the invention the working element terminates in a hot gas blow nozzle adjacent the distal end thereof. This allows for alternative uses, such as using the blown hot gas to strip or to shrink a material against which the gas is directed.

[0012] Preferably, a heating means is provided, and advantageously, the heating means is operably coupled to the heat conductive member or the hot gas blow nozzle for transferring heat thereto. [0013] In another embodiment of the invention a heating means is provided for producing a hot gas for delivery through the hot gas nozzle.

[0014] In one embodiment of the invention the heating means is located in the working element, and preferably, is located adjacent the proximal end thereof. This is a simple yet useful arrangement particularly suitable for soldering or knife cutting applications. [0015] In one embodiment of the invention the heating means comprises a gas powered heating means, and preferably, the heating means comprises a combustion chamber in which fuel gas is converted to heat, and ideally, a gas catalytic combustion element is located in the combustion chamber for catalytically converting fuel gas to heat. Gas powered devices are useful for many reasons including the fact that they can produce desired heating without requiring an electrical heat source. [0016] Alternatively, the heating means comprises an electrically powered heating means, which preferably, is provided by an electrically resistive heating element. [0017] In another embodiment of the invention a fuel gas reservoir is provided for fuel gas for powering the heating means, and preferably, the fuel gas reservoir is located in the handle. This allows for a compact arrangement.

[0018] In another embodiment of the invention the electrically powered heating means is battery powered, and ideally, the handle comprises a means for accommodating one or more batteries. This means that the device operation is not limited to being with a working distance of a power supply and the device is thus particularly useful where a power supply is not easily accessible.

[0019] Alternatively, the electrically powered heating means is mains electrically powered, and an electrical cable extends from the device, and preferably, from the proximal end of the handle thereof. [0020] In a further embodiment of the invention the handle is a pencil-like handle, and preferably, is of substantially circular transverse cross-section. This allows for a compact device with ease of gripping and use.

[0021] Desirably the device includes an indicator for indicating when the device is on. Any such suitable indicator may be employed. Desirably a light source is used. Such a light source may illuminate when the device is switched on. If desired the light source will illuminate until the device (after use) cools to a temperature which will not cause a burn to a user. In such an arrangement it can be considered a safety light. Having a light indicating the device is on makes it less likely that a user will inadvertently leave the device switched on when not in use. Desirably the light source is positioned within a housing of the device. This allows for a compact arrangement while ensuring the light source is protected. In one arrangement the light source is within a housing for the working element. The light source may be powered by an electrical source (e.g. battery and/or mains power) or alternatively may be gas-powered. The latter is desirable if there is a gas source within the device for heating etc.

[0022] It is further desirable that the position of the working element of the device may be adjusted relative to the handle. For example the working element may be pivotally mounted to the handle. This is advantageous in that the angle of the working element relative to the user may be adjusted for use. For example the angle of the working element may be changed to an angle that is more comfortable for the user. The angle of the handle and the working element when viewed in elevation from a first direction, in which an angle defined between the working element and the handle about the distal end of the handle is at a maximum value, the said angle is an obtuse angle, and preferably, the said obtuse angle lies in the range of 94° to 171 °. As such, the position of the working element may be adjusted relative to the handle such that the obtuse angle lies in the range of 94° to 171 °. Desirably the relative movement of the working element relative to the handle is limited by some limiting means such as a stop to a position wherein the obtuse angle is within the desired range at all relative adjustment positions. The angle may be changed by a working element position holding means. For example a screw in the mounting housing may be employed. The holding means may be released to allow movement of the working element. Once released, the element may be moved to the desired angle. When the desired angle is achieved the holding means can be reengaged to hold the working implement at the desired angle. [0023] It is further desirable that the working elements described above may be covered by a protective cap or sheath. The protective cap or sheath may be configured to cover the entire working element or a portion thereof for example the tip of the working element. The protective cap may be constructed from any material known to those skilled in the art, such as any plastic, metal, and the like. The protective cap may be shaped to any form, and does not have to be confined to the shape illustrated in the drawings. The protective cap provides a cover to the working element that may protect the working element against accidental damage for example when stored or when not in use etc.

[0024] Where suitable, it will be appreciated that all optional and/or preferred features of one embodiment of the invention may be combined with optional and/or preferred features of another/other embodiment(s) of the invention. Brief Description of the Drawings

[0025] Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the invention and from the drawings in which: [0026] Figure 1 is a perspective view of a portable heating device according to the invention

[0027] Figure 2 is a side elevational view of the heating device of Fig. 1

[0028] Figure 3 is a top plan view of the heating device of Fig. 1

[0029] Figure 4 is an end view of the heating device of Fig. 1 [0030] Figure 5 is a transverse cross-sectional side elevational view of the heating device of Fig. 1

[0031] Figure 6 is a transverse cross-sectional side elevational view of a detail of the portable heating device of Fig. 1 , differently configured

[0032] Figure 7 is a view similar to that of Fig. 6 of the heating device of Fig.1 in a different configuration to that of Fig. 6

[0033] Figure 8 is a view similar to that of Fig. 6 of the heating device of Fig.1 further differently configured

[0034] Figure 9 is a perspective view of the portable heating device of Fig. 1 illustrated in use [0035] Figure 10 is a perspective view of a portable heating device according to another embodiment of the invention

[0036] Figure 11 is a side elevational view of the heating device of Fig. 10

[0037] Figure 12 is an underneath plan view of the heating device of Fig. 10

[0038] Figure 13 is an end view of the heating device of Fig. 10 [0039] Figure 14 is a transverse cross-sectional side elevational view of the device of

Fig. 10

[0040] Figure 15 is a perspective view of the portable heating device of Fig. 10 in use

[0041] Figure 16 is a perspective view of a portable heating device according to another embodiment of the invention [0042] Figure 17 is a side elevational view of the heating device of Fig. 16

[0043] Figure 18 is a top plan view of the heating device of Fig. 16

[0044] Figure 19 is an end view of the heating device of Fig. 16,

[0045] Figure 20 is a transverse cross-sectional side elevational view of the device of

Fig. 16, [0046] Figure 21 is a side elevational view of a heating device of the invention incorporating an adjustable working element and a safety switch; and [0047] Figure 22 is a perspective view of the heating device of Fig. 21.

Detailed Description of the Drawings

[0048] It should be readily apparent to one of ordinary skill in the art that the examples disclosed herein below represent generalised examples only, and that other arrangements and methods capable of reproducing the invention are possible and are embraced by the present invention.

[0049] Referring to the drawings and initially to Figs. 1 to 9 thereof, there is illustrated a portable heating device according to the invention, which in this embodiment of the invention is configured for use as a portable gas powered soldering iron indicated generally by the reference numeral 1. The soldering iron 1 is also configurable as a hot air blower, a blow torch and a hot knife as will be described below with reference to Figs. 6 to 8. Referring now to Figs. 1 to 5 and Fig. 9, the soldering iron comprises an elongated pencil-type handle 3 which is formed by a hollow primary housing 5 which extends between a proximal end 6 and a distal end 7 and defines a central longitudinally extending primary axis 9. A working element 8 comprising an elongated hollow secondary housing 10 is mounted by a mounting means, namely, a mounting housing 1 1 to the handle 3 at the distal end 7 thereof. The secondary housing 10 extends between a proximal end 14 and a distal end 15 and defines a longitudinally extending central secondary axis 16. A heat conductive member, in this embodiment of the invention a soldering tool bit 18, extends from the secondary housing 10 adjacent the distal end 15 thereof, and terminates in a distal soldering tip 19 which lies on the secondary axis 16. In this embodiment of the invention the handle 3, the secondary housing 10 and the mounting housing 1 1 are of injection moulded plastics material and are formed by two half shells 20 secured together by screws (not shown). [0050] A heating means comprising a combustion chamber (not shown) is located in the secondary housing 10 for converting fuel gas to heat for in turn heating the soldering tool bit 18. The combustion chamber is formed in a combustion chamber housing 22 of heat conductive material, namely, brass, and the soldering tool bit 18 extends from and is in heat conductive engagement with the combustion chamber housing 22. A gas catalytic combustion element (not shown) is located in the combustion chamber of the combustion chamber housing 22 for converting fuel gas to heat by catalytic action. Such an arrangement of a combustion chamber housing, a gas catalytic combustion element and a soldering tool bit 18 will be well known to those skilled in the art. [0051] A fuel gas reservoir 23 for supplying fuel gas to the combustion chamber (not shown) is located in the handle 3. A button operated isolating switch 24 is operable for selectively supplying fuel gas from the reservoir 23 to the combustion chamber (not shown). The fuel gas which is stored in liquid form in the reservoir 23 is supplied to the combustion chamber (not shown) in gaseous form through a plurality of control elements, none of which are shown but which include a pressure regulator for regulating the pressure of the fuel gas at which the fuel gas is supplied to the combustion chamber, a flow control valve for controlling the flow rate of the fuel gas to the combustion chamber and a venturi mixer for mixing the fuel gas with air prior to being delivered into the combustion chamber through a nozzle (not shown). Such control elements and their arrangement will be well known to those skilled in the art. [0052] A piezoelectric igniter 25 is located in the secondary housing 10 for producing an ignition spark for igniting the fuel gas/air mixture in the combustion chamber (not shown) to initially burn with a flame for raising the temperature of the gas catalytic combustion element (not shown) to its ignition temperature. A button operated actuator 26 formed at the distal end of the secondary housing 10 is depressable into the secondary housing 10 for activating the piezoelectric igniter 25 to produce an ignition spark. The operation of such piezoelectric igniters for producing an ignition spark to initially cause a fuel gas/air mixture to burn in a flame for raising the temperature of a gas catalytic combustion element to its ignition temperature will be well known to those skilled in the art.

[0053] Turning now to the configuration of the secondary housing 10 of the working element 8 relative to the primary housing 5 of the handle 3, the secondary housing 10 is mounted to the handle 3 by the mounting housing 1 1 so that when the soldering iron 1 is viewed in elevation from a first direction, as illustrated in Fig. 2, the secondary axis 16 of the secondary housing 10 defines an obtuse angle α with the primary axis 9 of the order of 152°. Additionally, when the soldering iron 1 is viewed in plan from a second direction orthogonal to the first direction, as, for example, in Fig. 3, the primary axis 9 and the secondary axis 16 lie in a common vertical plane. Additionally, the mounting housing 11 offsets the secondary housing 10 from the handle 3, and in this embodiment of the invention the offset distance d perpendicular from the secondary axis 16 to the primary axis 9 at the distal end 7 of the handle 3 is approximately 15mm. [0054] The advantage of the configuration of the secondary housing 10 and in turn the soldering tool bit 18 relative to the handle 3 is that the handle 3 can be gripped between a thumb and the index finger, or between the thumb and the index finger as well as the next adjacent or the next two adjacent fingers to the index finger of a hand of a user with the distal end 7 of the handle 3 extending away from the tips of the index and other fingers so that the soldering tip 19 of the soldering tool bit 18 when brought into contact with a component to be soldered, for example, a component to be soldered onto an electrically conductive track of a printed circuit board is oriented so that the soldering tip 19 is directly viewable by the user, as can be seen in Fig. 9. Furthermore, the configuration of the secondary housing 10 relative to the handle 3 ensures that the soldering tool bit does not obscure the joint to be soldered between the component and, for example, a track on a printed circuit board. Accordingly, the soldering iron 1 provides the advantage over existing constructions of portable soldering irons in that both the soldering tip 19 and the area in which the solder joint is to be made are both clearly visible to the user, which is not possible with soldering irons known heretofore, whereby the soldering tip of a conventional soldering iron tends to obscure the area in which solder joint is to be made from the user. [0055] Referring now in particular to Figs. 6 to 8, in Fig. 6, the soldering iron 1 is illustrated with a hot gas blow nozzle 27 extending through the secondary housing 10 in place of the soldering tool bit. The hot gas blow nozzle 27 is engaged in the combustion chamber housing 22 and defines a hot gas accommodating bore 28 extending therethrough, which communicates with the combustion chamber (not shown) for accommodating hot exhaust gases from the combustion chamber, which in turn produce a hot gas stream for heating an area on which the hot gases are played. The hot gas stream from the hot gas blow nozzle may be used for heating plastic sleeves in order to shrink the plastic sleeves around an electrical joint between an electrical cable and an electrical connector tab. In Fig. 7, the soldering iron 1 is configured as a hot blow torch of the type suitable for stripping paint. In this case the soldering tool bit is replaced with a blow nozzle 27a, which is substantially similar to the blow nozzle 27, with the exception that a greater volume of heated exhaust gasses is delivered through the nozzle 27a, than is delivered through the nozzle 27. Needless to say the hot gasses delivered by the nozzles 27 and 27a may be used for any other desired purpose. [0056] In Fig. 8, the soldering iron 1 is configured as a hot knife, and in this case the soldering tool bit is replaced by a knife 27b, which is in heat conductive engagement with the combustion chamber housing 22 in a similar manner to that in which the soldering tool bit is in heat conducting engagement with the combustion chamber housing 22. The knife 27b is provided with a cutting edge 27c. The hot knife may be used for any purpose, for example, cutting plastics materials, cutting and cauterising ropes of plastics material. [0057] While the combustion chamber housing 22 and the secondary housing 10 are adapted for receiving the soldering tool bit, the heated knife as well as a hot gas blow nozzle and a blow torch nozzle, it will be readily apparent to those skilled in the art that the combustion chamber housing 22 is suitable for receiving any other elements for heating. Indeed, it will be readily apparent to those skilled in the art that the combustion chamber housing and the secondary housing is suitable for receiving soldering tool bits of many different sizes, shapes and configurations. Similarly, the combustion chamber housing and the secondary housing is suitable for receiving heated knives of different shape and configuration, and such heated knives of different shapes and configurations may also be provided. Needless to say, other suitable shapes and constructions of hot gas blow nozzles and blow torches may be provided. [0058] In use, with the reservoir 23 charged with a suitable fuel gas in liquid form, typically, butane gas, and with the soldering tool bit 18 secured in the combustion chamber housing 22, the soldering iron 1 is ready for use for soldering. The isolating switch 24 is operated to supply fuel gas to the combustion chamber (not shown), and the actuator 26 is depressed into the secondary housing 10 for operating the piezoelectric igniter 25 to produce an ignition spark for initially igniting the fuel gas/air mixture delivered to the combustion chamber 21 to burn with a flame. The flame raises the temperature of the gas catalytic combustion element (not shown) to its ignition temperature so that once the gas catalytic combustion element has reached its ignition temperature it commences to convert fuel gas to heat catalytically. This conversion of fuel gas to heat catalytically rapidly starves the flame of fuel gas, and the flame is extinguished. The conversion of fuel gas to heat by the catalytic combustion element raises the temperature of the combustion chamber housing 22, and heat is transferred from the combustion chamber housing 22 to the soldering bit 18 and in turn the soldering tip 19 thereof, which is rapidly brought to an appropriate temperature for soldering. With the soldering iron 1 gripped in the hand of a user as illustrated in Fig. 7, the soldering tip 19 is brought into contact with the item to be soldered as illustrated in Fig. 7. When soldering has been completed, the isolating switch 24 is operated into the off state, thereby isolating the combustion chamber from the fuel gas reservoir 23. [0059] When a hot gas stream is required, the soldering tool bit 18 is replaced with either the hot gas blow nozzle 27 or the blow torch nozzle 27a, depending on the volume and temperature of hot gasses to be delivered. Hot exhaust gasses from the combustion chamber of the combustion chamber housing 22 are directed through and exit the hot gas blow nozzle 27 or the blow torch nozzle 27a, as the case may be.

When it is desired to configure the soldering iron 1 as a heated knife, the soldering tool bit is replaced with the knife 27c, which in turn is heated by heat conduction from the combustion chamber housing.

[0060] Referring now to Figs. 10 to 15, there is illustrated a portable heating device according to another embodiment of the invention, which in this embodiment of the invention is also a soldering iron, which is indicated generally by the reference numeral 30. The soldering iron 30 is substantially similar to the soldering iron 1 and similar components are identified by the same reference numerals. The main difference between the soldering iron 30 and the soldering iron 1 is that the soldering iron 1 is electrically powered, as opposed to the gas powering of the soldering iron 1. In this embodiment of the invention the heating means is provided by an electrically powered heating element 31 which is located in the secondary housing 10 and is coupled with heat conducting engagement to the soldering tool bit 18 for transferring heat from the heating element 31 to the soldering tool bit 18. [0061] In this embodiment of the invention the heating element 31 is powered by four batteries 33 which are located in the handle 3. An on/off switch 35 located in the secondary housing 10 selectively couples the heating element 31 to the batteries 33. The batteries 33 may be rechargeable or non-rechargeable batteries, and are connected together in series by a suitable electrical circuit which couples the batteries 33 to the heating element 31 through the switch 35. [0062] Otherwise, the soldering iron 30 is similar to the soldering iron 1.

[0063] However, if desired, the soldering iron 30 may also be provided with a hot gas blow nozzle, which in this embodiment of the invention would blow hot air. A fan (not shown) would be located in the secondary housing 10, which would blow air across the heating element 31 , which in turn would be directed into the bore of a hot gas blow nozzle similar to the hot gas blow nozzle of the soldering iron 1.

[0064] The soldering iron 30 may also be provided with a knife similar to the knife 27b which would be inserted in place of the soldering tool bit should a heated knife be required.

[0065] Referring now to Figs. 16 to 20, there is illustrated a portable heating device according to a further embodiment of the invention, which in this embodiment of the invention is also a soldering iron, indicated generally by the reference numeral 40. The soldering iron 40 is substantially similar to the soldering iron 1 , and similar components are identified by the same reference numerals. In this embodiment of the invention the soldering iron 40 is electrically powered by mains electricity and comprises a heating element 41 which is similar to the heating element 31 of the soldering iron 30, and is in heat conductive engagement with the soldering tool bit 18. Electrical control circuitry (not shown) is located in the handle 3 for controlling the supply and voltage of the electrical power supply to the heating element. Mains electricity is supplied to the soldering iron 40 through an electrical flex 42 which terminates in a plug top (not shown) which is suitable for coupling to a mains electrically powered socket (not shown).

[0066] Referring now to Figs. 21 and 22, there is illustrated a portable heating device according to a further embodiment of the invention. Fig. 21 shows a side elevation of a device 1 which is similar in construction to that of other embodiments. It is desirable in all aspects of the invention that an indicator is provided for indicating when the device is on. Desirably it is a visual indicator. One arrangement incorporating an indicator is shown in Figure 21. Fig. 21 shows a side elevation of a device 1 which is similar in construction to that of other embodiments. In this embodiment the indicator is a light source 50 within a switch 35. As can be seen the light source 50 is within a housing 10 for the working element - in this case a soldering bit 18 covered by a protective cap 70. As indicated by double-headed arrow 51 the switch 35 is twisted to switch the entire device on and off. When the device is switched on the light source also switches on and glows, emitting light which can be seen through a domed end 52 of the switch. To move between on and off positions it is also necessary to push on the switch 35 (as indicated by arrow 53) so that a lug 54 moves within a cammed recess 55 in the switch 35. In the embodiment the switch is resiliently biased away from housing 10. It will be appreciated that any suitable type of indicator can be utilised. For example in the embodiment of Figures 1 to 9 it is possible to utilise an indicator in addition to switch 24 or incorporated within switch 24. The same applies to the embodiment of Figures 10 to 15 and the switch 35 thereof. An indicator may also be applied to the embodiment of Figure 16 to 20. The indicator may be powered by electrical power for example from a mains and/or battery power supply. It a gas energy source is used the indicator, for example a light, may be powered by the gas source. Some additional items are seen in Figure 21 , including a catch 56 for closure 57 of a battery compartment and screw 58 and a nut 58a holding two shell halves of the device together. [0067] Referring now to Fig. 22, there is illustrated a perspective view of the heating device of Fig. 21 , where similar components are identified by the same reference numerals. The secondary housing 10 (for the heating element) and the soldering bit 18 covered by the protective cap 70 (the soldering bit 18 is not visible in this view) are pivotally mounted on the mounting housing 11 of the primary housing 5 by a pivoting mounting means. As indicated by the double-headed arrow 61 , the secondary housing 10 is moved to change the angle of the soldering bit 18 covered by the protective cap 70 to a preferred angle for use by the user. In use, a working element position holding means, in the embodiment in the form of a holding screw 59, is loosened which permits the user to move the working element relative to the handle by virtue of a pivoting means in the form of a hinge 60 to a preferred position. When the soldering bit 18 covered by the protective cap 70 is in a preferred position, the screw 59 is tightened to secure the working implement (and also the covered soldering bit 18) in that position. A recess 62 in the mounting housing 1 1 accommodates the movement of the hinge 60 therein. It will be appreciated that having a working element that is adjustable relative to the handle is desirable for all aspects of the invention. [0068] It will be readily apparent to those skilled in the art that the heating elements of the soldering irons 30 and 40 may be adapted for receiving different types of tool bits. [0069] While the soldering irons have been described as comprising a handle, a secondary housing and a mounting housing of plastics material which is formed by two shells secured together, the soldering irons may be of any other suitable material and of any other suitable construction, and where the soldering irons are of plastics material, they may be formed by methods other than injection moulding. [0070] The invention is not limited to the embodiments hereinbefore described, which may be varied in construction and detail. [0071] The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. [0072] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.