Abstract:
A variable-width toaster is described, in which the food-supporting carriage ( 5, 60 ) adapts readily, robustly and in a cost-effective manner to different width settings of the toasting chamber ( 2, 70 ). Respective elongate members ( 51, 52; 61, 62 ) are mounted to either side of the toasting chamber and are linked together by linking members ( 53   a - 53   n;    63   a,    63   b ) which form part of the food-supporting surface and are pivotally attached to the elongate members to accommodate lateral relative movement between the elongate members as the width of the toasting chamber is varied. In one embodiment, unitary linking members ( 53   a - 53   n ) link the two elongate members ( 51, 52 ) and the elongate members are urged apart by a spring ( 54 ). In another embodiment, chevron-like linking members, comprising pairs of pivotally associated linking members ( 63   a,    63   b ) are employed.

Description:
FIELD OF THE INVENTION 
     This invention relates to toasters, and it relates especially, though not exclusively, to toasters intended for use in the domestic kitchen. 
     BACKGROUND OF THE INVENTION 
     Electrically operated toasters are stock items in most domestic kitchens, and they tend to be reasonably robust and reliable in use, despite the relatively modest purchase prices which have come to be established for them. Changes in traditional eating habits, however, leading to the development of popular taste for a wider variety of toastable foodstuffs, have recently led to technical developments which have increased the sophistication of toasters, enhancing their efficiency and providing greater flexibility of use. 
     One particular aspect of toasters which has received attention in this respect is their ability to cope with foodstuffs of quite widely differing dimensions; in particular, the thickness dimension of foodstuffs which users may wish to toast can vary widely. Several proposals have thus been made for so-called “variable slot” toasters which can accommodate foodstuffs having width dimensions ranging from relatively narrow, say for thinly-sliced bread, to relatively wide, for bagels and similar products. 
     Not all of these proposals have been commercially successful, however, and it is believed in this respect that (inter alia) difficulties have been experienced in constructing certain internal components whose dimensions need to change with variations in slot width economically whilst maintaining ruggedness and reliability in operation, bearing in mind that such internal components operate in an extremely hostile and challenging environment. 
     Such difficulties as aforementioned are particularly acute in respect of the foodstuff-supporting carriage, which is mobile within the toaster slot; this carriage being latched down in a lower position to support the foodstuff adjacent the heater elements whilst it is being toasted, and then released to spring upwards when the toasting cycle is complete, thereby presenting the toasted foodstuff for easy withdrawal from the toaster slot. It is well known for the heating elements to be de-energised when the carriage is raised to its presentation position, and for the latching-down mechanism to be ineffective unless power is applied to the toaster. 
     It will be appreciated that the carriage needs to be capable of reliably supporting a wide variety of foodstuffs whatever the slot position set by the user, since potentially hazardous situations could arise if this were not the case. For example, the toaster could jam with the carriage down (and thus the heaters energised) if foodstuffs could become entrapped between an edge of the carriage and a heater element or heater support and thus a potential fire hazard could arise. In this respect, it needs to be borne in mind that a user might inadvertently set (or leave) the slot at a wide position whilst attempting to toast a relatively thin food item. 
     SUMMARY OF THE INVENTION 
     The present invention aims to provide a variable-slot toaster with a carriage which is capable of adapting reliably to variations in slot width and which is economic to manufacture. 
     According to the invention there is provided a toaster having a slot-like chamber into which foodstuffs to be toasted can be placed, the chamber being flanked by respective heating elements; a carriage having a foodstuff-supporting surface; a support structure for said carriage configured to permit the carriage to be latched in a lower position at which foodstuffs are exposed to said heating elements for toasting, for releasing said carriage on completion of a toasting cycle, and for raising the carriage to an upper, presentation position in which toasted foodstuffs can be removed from the toaster; and user-operable means for varying the width dimension of the chamber to accommodate foodstuffs of differing thickness; wherein the carriage comprises first and second elongate members extending along the length dimension of said chamber and disposed respectively to one and the other side of said chamber; a plurality of linking members linking said elongate members and pivotally mounted to each, said linking members collectively presenting at least a substantial part of the foodstuff-supporting surface of the carriage; and control means maintaining said elongate members in contact with opposing sides of the chamber such that said elongate members move relative to one another when the width dimension of the chamber is varied; such movement of the elongate members being accommodated by pivotal movement of said linking members, whereby said carriage adapts automatically to said variations in the width dimension of said chamber. 
     In one preferred embodiment, the control means comprises latching means latching the elongate members to opposing sides of the chamber, whereby movement in the width dimension of the chamber pushes said elongate members closer together or pulls them farther apart, depending upon the user-selected setting of the said width dimension. 
     By this means, no dedicated operational means are required to adapt the width of the carriage to variations in the width dimension of the chamber. 
     Conveniently in such an arrangement the linking means comprise a plurality of chevron-like links distributed along the length of the elongate members and having pivots at the chevron points permitting the chevron angle to vary with variations in the width dimension of the chamber. 
     The chevron-like links may be regularly distributed along the length of the elongate members, and the elongate members may be notched to receive the chevron point pivots when the chamber is adjusted to its narrowest width dimension. 
     In another preferred embodiment, the control means includes resilient means acting upon at least one of said linking members for urging said elongate members apart. 
     In one such preferred embodiment, the resilient means comprises a coil spring, configured to operate in either compression or tension, fixedly supported upon one of said elongate members and connected to at least one of said linking members. By this means, the necessary resilient urge is applied in a simple and cost-effective manner. 
     In another preferred embodiment, the resilient means comprises a torsion spring; the shape and dimensions of which may, in some configurations, prove more convenient or more compact in use than a coil spring. 
     In other preferred embodiments, the resilient urge is provided by plural spring members carried by one of said elongate members; each of said spring members being coupled between a respective fixed location on said elongate means and a respective one of said linking members. It is further preferred that said spring members are evenly distributed among said linking members. In such circumstances, coil springs or torsion springs, or a combination of both, may be used. 
     It is further preferred that pivotal mounting points for the linking members are regularly distributed along the elongate members, thereby providing an even distribution of the resilient urging force. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be clearly understood and readily carried into effect, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: 
         FIG. 1(   a ) shows, in perspective view, part of a toaster in accordance with a first embodiment of the invention, with a wall of the toasting chamber removed to illustrate the carriage in relation to other internal components of the toaster; 
         FIG. 1(   b ) shows a plan detail of a slider component of the toaster; 
         FIG. 2  shows, in perspective view, essential components of a carriage for a toaster in accordance with said first embodiment of the invention; and 
         FIGS. 3 ,  4  and  5  show, in a partial plan view from the top, essential components of a carriage for a toaster in accordance with a second embodiment of the invention, respectively disposed at wide ( FIG. 3 ), medium ( FIG. 4 ) and narrow ( FIG. 5 ) settings. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIGS. 1 and 2  of the drawings, a toaster in accordance with one embodiment of the invention comprises a main housing  1  in which is defined a slot-like toasting chamber  2 , flanked by respective heating elements, such as that shown at  3 , of any convenient kind. The heating elements are typically substantially rectangular, planar elements as shown, supported in known manner so as to stand vertically to either side of chamber  2 , effectively forming side-walls thereof. Each heating element is, in this example, protected by a grid-like guard member  4  from direct contact with the foodstuffs inserted into the chamber  2 . 
     A food-supporting carriage  5  is provided in the chamber  2 , and the carriage is supported, in known manner, by means of a conventional support structure (not shown) configured to permit the carriage to be latched in a lower position at which foodstuffs are exposed to said heating elements for toasting, for releasing said carriage upon completion of a toasting cycle, and for raising the carriage to an upper, presentation position in which toasted foodstuffs can be removed from the toaster. 
     User-operable means, including a slider mechanism  6  is provided for varying the width dimension A of the chamber to accommodate foodstuffs of differing thickness. In this example, the mechanism  6  is disposed internally of an outer casing (not shown) of metal or plastics material and is operated by means of a lever arrangement (not shown) accessible to the user externally of the casing. The internal mechanism  6  includes, in this example, a slot arrangement  7  (best seen in  FIG. 1(   b )) comprising several constrictions which define respective discrete width settings for the slot-like chamber  2 . In alternative embodiments, the width setting may be smoothly variable to any chosen position between two extreme end stops. 
     As shown in more detail in  FIG. 2 , the carriage  5  comprises first and second elongate members  51  and  52  extending along the length dimension B of said chamber and disposed respectively to one and the other side of the chamber  2 . A plurality of linking members  53   a  to  53   n  are provided, each linking the elongate members  51  and  52  and pivotally mounted to each elongate member; and resilient means  54  are provided to urge the elongate members  51  and  51  apart whereby the carriage  5  adapts automatically to variations in the width dimension A of the chamber. In this respect, it will be appreciated that in this embodiment the member  52  remains in contact with the heater guard in its side of the slot  2  whilst the member  51  is mobile laterally of the toaster slot; moving towards or away from the member  52  as appropriate to maintain contact with the heater guard at the other side of the slot. The member  51  is either pushed towards the member  52  by contact with the heater guard  4  when the slot  2  is narrowed by a user, or urged away from the member  52  by the resilient means  54  when the slot  2  is widened. 
     In this example of the invention, the resilient means  54  comprises a single coil spring, fixedly supported upon the elongate member  52  and configured to operate in compression, though it could alternatively, be mounted and configured so as to operate in tension, depending upon the detailed construction of the assembly. Also in this example, the spring is connected to the linking member  53   a  but it could alternatively, or in addition, be connected to one or more of the other linking members. By this means, in any event, the necessary resilient urge is applied in a simple and cost-effective manner. 
     In further alternative configurations, the resilient urge may be provided by a torsion spring, and/or by plural spring members of any convenient kind carried by one, the other, or both of the elongate members  51  and  52 ; each such spring member being coupled between a respective fixed location on its elongate means and a respective one or more of the linking members. If plural spring members are provided, it is preferable to distribute them evenly among said linking members. 
     It is particularly preferred (though not essential) that pivotal mounting points for the linking members  53   a  to  53   n  are regularly distributed along the elongate members  51  and  52 , thereby providing an even distribution of the resilient urging force. 
     In some preferred embodiments of the invention, the mobile member  51  (or at least a part thereof) is usefully made of, or coated with, a robust and slippery material, such as a ceramic or a non-stick material such as that sold under the registered trademark Teflon®, which will resist repeated wiping contact with the heater guard  4 . 
     Referring now to  FIGS. 3 ,  4  and  5 , which show various operational thickness settings for a toaster in accordance with a second embodiment of the invention, the carriage  60  comprises first and second elongate members  61  and  62  extending, as before, along the length dimension B of the toasting chamber  70  and disposed respectively to one and the other side of the chamber  70 . A plurality of paired, chevron-like linking members such as  63   a  and  63   b  are provided; each linking member being pivotally linked to a respective elongate member  61  or  62  and each pair of linking members, such as  63   a  and  63   b  being pivotally linked to each other, as at  64 ,  65 , and  66 . Each end of each of the elongate members  61 ,  62  is secured by means of an eye such as  67  to an upright wire such as  68  forming part of the heater guard at the relevant side of the chamber  70 , such that the carriage  60  can execute its required vertical movements simply by each eye such as  67  running up or down on its respective wire such as  68 . When the toaster chamber is widened or narrowed, however, the elongate members follow the relevant movement towards or away from another as a result of their direct attachment to the wires such as  68 . 
     In this embodiment of the invention, therefore, there is no need for any resilient means to urge the elongate members apart, as there was in the first embodiment, since the carriage  60  adapts, as a result of its construction, to variations in the width dimension A of the chamber  70  simply by the elongate members  61  and  62  being towards each other or pulled away from each other as appropriate by their direct mechanical connection to the wires such as  68 . 
     It will also be appreciated that, because of the folding capability of the pairs of linking members such as  63   a  and  63   b  afforded by their central pivots such as  66 , the overall longitudinal offset between the two elongate members  61  and  62  that needs to be accommodated in the second embodiment of the invention is only around half of that needed for the elongate members  51  and  52  in the first embodiment. 
     The inner surface of each of the elongate members  61  and  62  (i.e. that surface facing away from the heaters and thus into the interior of the chamber  70 ) is formed with a plurality of notches, such as  69 , to accommodate the central pivots, such as  66 , of the respective pairs of linking members, such as  63   a  and  63   b , when the toasting chamber  70  is set to a narrow setting as illustrated in  FIG. 5 . 
     In some preferred embodiments of the invention, the eyes such as  67  are usefully made of, or coated with, a robust and slippery material, such as a ceramic or a non-stick material such as that sold under the registered trademark Teflon®, which will resist repeated wiping contact with the wires such as  68  during upward and downward movements executed by the carriage  60  at various stages during the toasting process. Alternatively, or in addition, the wires such as  68  may be so formed or coated. Alternatively, any convenient form of linear bearing capable of operating in the toasting chamber environment can be used to link the elongate members  61  and  62  to the wires such as  68 .