Abstract:
A toaster includes a housing having an upper wall with bagel half shaped openings; toasting chambers in the housing accessible through the openings and having bagel half shapes; a bread rack in each toasting chamber; inner/outer heating coils surrounding each toasting chamber; electric contacts in the housing for activation of the heating coils; a raising/lowering mechanism connected with the bread racks for moving the bread racks up and down, and including first and second lateral portions connected to opposite ends of the bread racks; first and second guides mounted to the housing for guiding the first and second lateral portions with a small tolerance, a yoke housing connected with the first lateral portion and slidably movable relative to the housing, a lever slidably moving the yoke housing; a yoke slidably movable relative to the yoke housing and closing the electric contacts when the bread racks and yoke are lowered, and a first spring biasing the yoke upwardly; an electromagnet holding the yoke in the lowered position; an input setting device for setting a toasting time and/or a desired food item; a microprocessor controlling the electromagnet to release the yoke after a predetermined cooking time and controlling activation of the heating coils in response to the input setting device; and LEDs on an outer surface visually indicating the toasting time progression.

Description:
RELATED APPLICATIONS 
     This application is a continuation of prior application Ser. No. 09/388,675 filed on Sep. 2, 1999 now U.S. Pat. No. 6,123,012. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to toasters, and more particularly, is directed to a toaster providing varied toasting features and a safety control. 
     BACKGROUND INFORMATION 
     With conventional toasters, when a slice of toast or pastry gets lodged in the toast chamber during toasting, there generally is no fail-safe device for shutting off power to the heating elements. This can result in the toast or pastry being overcooked or burnt, and more importantly, can result in more hazardous occurrences, such as a fire. 
     Many currently available toasters rely on a timing circuit to release a solenoid or electromagnet which in turn releases the bread racks, along with a set of mechanical contacts for controlling voltage to the heating elements. The problem with these toasters occurs when the bread or pastry becomes jammed at the bottom of the toast rack and the electrical contacts are not sufficiently opened to turn off the heating elements. 
     Further, with existing toasters, the toast lowering mechanism is usually formed by bread racks, one per slot, connected at one end to a yoke assembly which slides vertically on a metal rod, and a knob for actuating the same. The opposite end of each bread rack is guided imprecisely in large slots punched out in the metal housing. This design translates to a loose, imprecise and noisy operator control. 
     Further, with many toasters there is no adequate display for indicating the shade of the toast, that is, such displays are not precise. 
     Still further, most slots for food are rectangular on exiting toasters. However, with bread items which do not have planar sides, such as bagels, it is often desirable to toast only one side of the bagel. Currently, some toasters do attempt to offer this feature, using a mechanical lever to switch off certain sides of the slots, but this requires the user to consider which orientation the toast or bagel is placed in the toaster, and therefore, the likelihood of negative results is high. Therefore, even if a toaster includes a control to allow the user to choose not to toast both sides of a bagel, there would be no obvious proper orientation for loading the bagel corresponding to the control, so that this would limit the usefulness of the feature to the user. 
     In addition, conventional toasters do not permit non-toasting functions such as defrosting food items or reheating food items after toasting. 
     Lastly, conventional toasters do not take into account differences in the original state of the item to be toasted, such as frozen foods, i.e., frozen waffles, and non-frozen foods, i.e., bread. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a toaster that overcomes the aforementioned deficiencies of the prior art. 
     It is another object of the present invention to provide a toaster having an automatic shutoff feature. For example, the present invention allows a minimum overtravel built into the lever/yoke mechanism of the toast rack lever to permit movement of the lever past the lowest position of the toast in the chamber so that after the toasting cycle, the lever/yoke mechanism is released to travel a minimum distance sufficient to ensure that the electrical contacts are fully open prior to engaging the toast rack. Therefore, if the bread or pastry is jammed, the heating elements will have already been shut off, and there will be no further burning of the food. 
     It s still another object of the present invention to provide a toaster that includes a means for indicating to the user that the bread is jammed, such as by a flashing LED and/or audible buzzer. 
     It is yet another object of the present invention to provide a toaster having an improved toast lever mechanism for smooth operation. For example, the present invention includes a plastic or other non-metallic part which is connected to the free end of the bread racks and is formed by a pin or the like which functions as a precise guide in a vertical slot in the heat shield or other metal surface adjacent the rear wall of the toaster. This allows the bread racks to be supported and guided at both ends thereof, which gives the benefit of more precise control and reduced chatter. 
     It is a further object of the present invention to provide a toaster with a toast shade control display incorporating, for example, a radial array of light emitting diodes (LEDs) on the printed circuit board inside the toaster which transfer light via light pipes to the exterior surface of the toaster. For example, the LEDs are arranged in a radial pattern around a rotary control knob, and are sequentially turned on and off as the knob is rotated by the user for selecting the desired toast shade. In addition, the display may include a countdown feature which would display a decreasing or increasing light bar effect approaching the selected LED as the toast cycle is progressing to its conclusion. A variation to the light bar effect may be a moving or flashing LED that would progress to its conclusion. 
     It as a still further object of the present invention to provide a toaster with an improved toasting operation for bagels. For example, an embodiment of the present invention includes slots which are shaped to indicate the proper orientation of the bagel so that when a user specifies a bagel as the food item, only the sliced planar surface, and not the outer curved surface, of the bagel half will be toasted. The toaster control may include a pushbutton or mechanical switch to indicate that the food item is a bagel. If a bagel is selected, then the outer heating elements or cards are turned off by means of a switch or relay. Another variation may allow for the outer heating elements or cards to be turned “off” at a reduced time to allow light toasting on the outer curved surface of the bagel half. 
     It is a yet further object of the present invention to provide a toaster with additional control selection to allow for non-toasting functions of the toaster, such as defrosting food items or reheating food items after toasting. For example, this selection uses the same heating control (that is, the same voltage, current, etc.) but with a reduced cycle time. 
     It is another object of the present invention to provide a toaster with a pushbutton selection that allows the user to toast frozen items such as frozen waffles. For example, the electronics would add a preset amount of time to the normal toast cycle to compensate for the defrosting of the item before the actual toasting cycle occurs. 
     The above and other objects, features and advantages of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a toaster according to an exemplary embodiment of the present invention; 
     FIG. 2 is a top plan view of the toaster of FIG. 1, with the heating elements, wire mesh shields and toast racks removed; 
     FIG. 3 is an end elevational view of the toaster of FIG. 1; 
     FIG. 4 is a side elevational view of inner operating parts of the toaster of FIG. 1 in an inoperative position, with the housing shown in phantom; 
     FIG. 5 is a side elevational view similar to FIG. 4, but in a toasting position; 
     FIG. 6 is a side elevational view similar to FIG. 4, but in a safety shutoff position after a toasting operation has been completed; 
     FIG. 7 is an end elevational view of a portion of the inner operating parts of FIG. 4, viewed from line  7 — 7  thereof; and 
     FIG. 8 is an exemplary block diagram of the circuitry for operating a toaster according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings in detail, a toaster  10  according to an exemplary embodiment of the present invention includes a toaster housing  12  of a generally rectangular parallelepiped configuration with opposite side walls  14  connected together by opposite end walls  16 , a bottom wall  18  and a top wall  20 . 
     Two adjacent and separated toasting chambers  22  are formed in toaster housing  12 . Each toasting chamber  22  is open at the upper end thereof through openings  24  in top wall  20 . In accordance with an exemplary aspect of the present invention, as will be understood from the discussion hereinafter, each toasting chamber  22  and corresponding opening  24  has a generally rectangular configuration, except that, for example, the outer sides  26  are bowed outwardly toward the respective side wall  14  of toaster housing  12 . With this arrangement, toasting chambers  22  are adapted to easily accept sliced bagel halves therein, with the bagel halves being oriented in a predetermined relation, that is, with the outer surfaces of each bagel half always facing outwardly, and the inner cut surfaces of each bagel half always facing inwardly. Thus, bagel halves always have a predetermined orientation in each toasting chamber  22 . It is foreseen that other predetermined orientations can also be employed. 
     Heating elements  28 , such as heating coils or heating cards, are secured within toaster housing  12  on opposite sides of each toasting chamber  22 , for example, by wire ties  30  or any other suitable arrangement, as shown best in FIGS. 1 and 5, as is conventional. Alternatively, heating elements  28  can be wound around a mica card from bottom to top and fastened by welding to metal contacts at both ends. The number of turns at the bottom compared to the number of turns at the top determines the effectiveness of achieving even browning in the toasting operation and can be adjusted accordingly. The heating elements  28  are merely shown schematically, and are omitted from FIGS. 2,  4  and  6  for the sake of clarity of the drawing. Further, as is conventional, a wire mesh or other shield  32  is provided in shielding relation to heating elements  28  to prevent the bread from directly contacting heating elements  28 . Shield  32  is shown schematically in FIG. 1, but omitted from the remaining figures for the sake of clarity of the drawings. Exemplary control for variations in operating voltages for heating elements is described in U.S. Pat. No. 5,844,207 which is hereby incorporated by reference. 
     According to an exemplary embodiment of the present invention, openings  24  are shaped to indicate proper orientation of the bagel haves so that when a user specifies a bagel as the food item, only the sliced inner face, and not the outer curved surface of the bagel half will be toasted. In such case, a control pushbutton  84  (FIG. 3) or mechanical switch on one end wall  16  indicates that the food item is a bagel. If a bagel is selected, then the outer sides of the heating elements  28  are turned off by means of, for example, a switch or relay. Alternatively, the outer sides of the heating elements  28  may be turned “off” after a shorter time period than inner ones of heating elements  28  to allow light toasting on the outer curved surface of the bagel halves. 
     A bread rack  34  is positioned in each toasting chamber  22  between the respective heating elements  28  (FIG.  4 ), and is adapted to move up and down between the upper position shown in FIG.  4  and the lower toasting position shown in FIG.  5 . Bread racks  34  are omitted from FIG. 2 for the sake of clarity of the drawing. Each bread rack  34  includes, for example, a lower, horizontally oriented, supporting bar  36  on which a food item, such as bread, is supported. One end of each supporting bar  36  is connected with, for example, an enlarged head  38  having a feature to mate with the connecting member  46  of yoke housing member  44  that receives a vertical guide pole  40 , the latter being secured at upper and lower ends thereof to the toaster chassis. A coil spring  42  is positioned on guide pole  40  below enlarged head  38  so as to normally bias enlarged head  38 , and thereby bread racks  34  upwardly to the inoperative position shown in FIG.  4 . 
     Yoke housing  44  is positioned, for example, above enlarged head  38  and also is slidable on vertical guide pole  40 . A bifurcated yoke  48  is slidably mounted to yoke housing  44 . For example, yoke  48  includes an upper lateral extension  50 , a lower lateral extension  52  and a vertical connecting member  54  which connects together lateral extensions  50  and  52  in vertically spaced relation. Yoke housing  44  is partially broken away in FIGS. 4-6 so that this can more easily be seen. Vertical connecting member  54  is slidably mounted on guide pole  40  and extends out, for example, through a vertically oriented, elongated slot  58  in yoke housing  44 . The coil spring  42  is positioned about guide pole  40 , below bifurcated yoke  48  so as to bias yoke  48  upwardly to the position shown in FIGS. 4 and 6. 
     Lateral extension  50  of yoke member  48  is connected to, for example, a lever  62  that extends out through an elongated slot  64  (FIG. 1) of toaster housing  12 . A knob  65  is formed at the free end of lever  62  that extends out of elongated slot  64  for engagement by a user&#39;s finger, in order to move lever  62  between the positions shown in FIGS. 4 and 5. 
     In accordance with an exemplary aspect of the present invention, the opposite end of bread rack  34  includes a plastic or other non-metallic guide member  66 , such as a pin or the like, which functions as a precise guide in a vertical slot  68  defined in the heat shield or other metal surface  70  at or near the rear wall of housing  12  of toaster  10 , with a width of slot  68  being only slightly larger than a width of guide member  66 . This allows bread racks  34  to be supported and guided at both ends thereof with a small tolerance, which gives the benefit of more precise control, a smoother operation of lever  62 , and reduced chatter. 
     When bread racks  34  are moved down to the position of FIG. 4 by depressing knob  65  of lever  62 , yoke  48  which is connected to lever  62  is pushed down guide pole  40 , thereby compressing spring  42 . Movement of yoke  48  also moves yoke housing  44  down along guide pole  40 , thereby resulting in bread racks  34  moving down to the position of FIG.  5 . Electromagnet  80  provides, for example, a stop in the downward direction. 
     In his position, lower lateral extension  52  closes electrical contacts  72  connected to a circuit board  74 , which supplies a signal to a conventional microprocessor  76  as illustrated in FIG. 8. A read only memory (ROM)  78  is connected with microprocessor  76  and has a predetermined program stored therein for operating microprocessor  76 . In response to the closing of contacts  72 , microprocessor  76  controls the supply of cower to heating elements  28 , thereby starting the toasting operation. At the same time, an electromagnet  80  positioned adjacent to yoke  48  is activated to hold yoke  48  in position for a time period determined by microprocessor  76  (e.g., determined by the software stored in ROM  78  and executed by microprocessor  76 ) and also to maintain the supply of power to heating elements  28 . In this regard, timing should be accurate within, for example, plus or minus 7%. To accomplish this, a line frequency or crystal frequency is generally required for a time base. Thus, microprocessor  76  can use an RC or internal oscillator if calibrated from a line frequency input. Further, cycle time changes as the square of the input voltage, which will generally be within the range of, for example, 108-127 volts. 
     Further, actual times at each setting can be empirically determined so the software stored in ROM  78  corresponds to the same. As an example, for a first time heating operation or first cycle, for 120 volts at 60 Hz power applied, a light toast setting would be, for example, for 80 seconds, and a dark toast setting at 160 seconds. If a second toasting operation or second cycle is started thereafter, that is, after the toaster is already warm, the time settings would change, for example, to 60 seconds for a light toast setting and 120 seconds for a dark toast setting. For a third toasting operation or third cycle, the time settings would change, for example, to 50 seconds for a light toast setting and 100 seconds for a dark toast setting. 
     As discussed above, it sometimes occurs in known devices that, after the toasting operation has been completed, if a slice of toast or pastry becomes jammed at the bottom of the toast rack and the electrical contacts are not sufficiently opened to shut off the heating elements, there is no fail-safe device for shutting off power to the heating elements. This can result in the toast or pastry being overcooked or burnt, and more importantly, can result in more hazardous occurrences, such as a house fire, etc. 
     Such a circumstance is avoided according to an exemplary embodiment of the present invention. For example, when the toasting operation is completed, that is, the time set for toasting has ended, microprocessor  76  deactivates electromagnet  80 . As a result, yoke  48  is no longer held by electromagnet  80  and is free to move. At such time, yoke  48 , which s no longer restrained, is biased up along guide pole  40  by spring  42  to the position shown in FIG.  6 . In this position, although bread racks  34  are still in the lowered position due to the toast or pastry jam, lower lateral extension  52  no longer closes the electrical contacts  72 , whereby heating elements  28  are no longer activated. Therefore, even though the toast or pastry is stuck at the bottom with bread racks  34 , the heating elements are no longer on, thereby eliminating any danger from an overheating operation. 
     Thus, an exemplary embodiment of the present invention allows a minimum overtravel of yoke  48  and lever  62  to permit a small movement of yoke  48  past the lowest position of the toast in toasting chambers  22  so that after the toasting cycle, such small movement of yoke  48  is sufficient to ensure that contacts  72  are fully open before a person engages bread racks  34  to release the jammed toast or pastry. For example, there can be an approximately ¼″ play (e.g., movement) so that the yoke housing  44  is limited in its downward movement by the end of the elongated slot  64  in the toaster housing  12  that limits the bread rack  34  travel. Thus, the bread rack  34  reaches its end of travel condition approximately ¼″ before the bifurcated yoke  48  contacts the electromagnet  80 . At the end of a cycle, the bias of spring  42  returns the bifurcated yoke  48  to the upward bias and causes it to travel approximately ¼″ to push against the yoke housing  44 . Therefore, if the bread or pastry is jammed, heating elements  28  will have already been shut off, and there Will be no further burning of the food as the contacts controlling power to the heating element  28  will be in full open position ensured by the ¼″ travel of the bifurcated yoke  48 . 
     In addition, toaster  10  may include a warning device  82  for warning the consumer that the bread is jammed. Warning device  82  can be a visible warning device, such as a flashing light emitting diode (LED) and/or an audible warning device, such as an audible buzzer or other alarm that is activated by microprocessor  76 . In this regard, a position sensor can be provided to determine the lowered position of bread racks after a toasting operation has been completed. 
     As discussed above, an exemplary embodiment of the present invention includes slots or openings  24  which are shaped to indicate proper orientation of a sliced bagel half so that when a user specifies a bagel as the food item, only the planar sliced inner surface, and not the curved outer surface, of the bagel half will be toasted. In addition to providing for the proper orientation of the bagel halves by the slots having a specific configuration, the present invention provides a control so that only the inner ones of heating elements  28  which face the sliced planar surface of the bagel are activated for heating. In this regard, for example, a pushbutton  84  or mechanical switch is provided on the end wall  16  opposite to lever  62 , and when depressed, sends a signal to microprocessor  76  to indicate that the food item is a bagel, and microprocessor  76 , in turn, then activates only the inner ones of heating elements  28 . In other words, the outer ones of heating elements or cards  28  are turned off by means of a switch or relay. 
     Alternatively, microprocessor  76  may also turn on the outer ones of heating elements  28 , but for a reduced amount of time in comparison with the inner ones of heating elements  28 . This permits light toasting on the curved outer surface of the bagel halves. 
     In addition to the bagel pushbutton  84 , toaster  10  can be set for toasting items other than toast and bagels, such as English muffins. In this regard, for example, an English muffin pushbutton  85  can be provided on the same end wall  16 . The default setting if button  84  or button  85  is not depressed is the conventional toast setting. 
     It will be appreciated that, when either pushbutton  84  or pushbutton  85  is depressed, a signal will be sent to microprocessor  76  to change the toast settings, depending upon the software stored in ROM  78 . For example, an English muffin could be twice the time of toast, and a bagel 20% less time than the English muffin. 
     As also discussed above, with many conventional toasters, there is no adequate display for indicating the shade of the toast, that is, such displays are not precise. An exemplary embodiment of the present invention provides a toast shade control display  86  incorporating, for example, a radial array of a plurality of light emitting diodes (LEDs)  88  on the same end wall  16  of housing  12  as pushbuttons  84  and  85 . For example, LEDs  88  are arranged in an arcuate pattern around a rotary control knob  90  which the user adjusts for a darkness setting, that is, which controls a rotary potentiometer  92  to supply a signal to microprocessor  76 . LEDs  88  are, for example, sequentially turned on and off as rotary control knob  90  is rotated by the user for selecting the desired toast shade. Accordingly, the user can easily determine the darkness setting. In other words, LEDs  76  identify the potentiometer setting, and the darkness control is thereby used by microprocessor  76  to control the toast time, and thereby the toast darkness. 
     In addition, display  86  may include a countdown feature which displays a decreasing light bar effect, approaching the preselected or darkness setting LED  88 , as the toast cycle is progressing to its completion. In such case, the user would select the desired shade using the rotary control knob  90  and LEDs  88 , and would then start the toast cycle by lowering toast lever  62  to its full bottom position. When the toast cycle starts, microprocessor  76  would, for example, activate LEDs  88  in a clockwise manner via an LED driver circuit  87 , up to the darkness setting selected by the user. As time progresses in the toasting cycle, microprocessor  76  could control LEDs  88  to turn off progressively in a clockwise manner, starting from the lightest setting LED until the only light left on is the one LED  88  corresponding to the desired darkness shade. At the end of the toasting cycle, display  86  defaults to the medium setting. Alternatively, LEDs  88  can start extinguishing from the darkness setting to the lightest setting LED. 
     As also discussed above, conventional toasters do not permit non-toasting functions such as defrosting food items or reheating food items after toasting, and do not take into account differences in the original state of the item to be toasted, such as frozen foods, i.e., frozen waffles, and non-frozen foods, i.e., bread. 
     An exemplary embodiment of the present invention provides additional control selection to allow for non-toasting functions of the toaster, such as defrosting food items or reheating food items after toasting. This selection uses, for example, the same heating control, that is, the same voltage, current, etc., but with a very reduced cycle time (heating time). The user control would be at an extreme position of the shade control knob, but would operate separate from the LED display discussed above. In such case, the user control could be indicated by, for example, the word “WARM” or “REHEAT” printed at the extreme end of the shade select control knob  90 . Alternatively, a first preset pushbutton  94  could be provided on the same end wall  16  of housing  12  as pushbutton  84 , and which provides a signal to microprocessor  76  in order to set the heating time. For example, the warm cycle could be one-half the lightest setting time for the selected food. 
     Further, according to an exemplary embodiment of the present invention, toaster  10  is provided with a pushbutton selection that allows the user to toast frozen items such as frozen waffles. For example, the software stored in ROM  78  could add a preset amount of time, such as 30%, to the normal toast cycle to compensate for the defrosting of the item before the actual toasting cycle occurs. In this regard, a second preset pushbutton  96  or momentary tactile switch with a corresponding LED thereon that is caused to be illuminated by microprocessor  76  can be provided. It is noted that toast may be presumed, that is, the default, if no food select LED is lit. A third preset pushbutton  98  can be provided for a third food item. 
     Alternatively, a single rotary switch can be provided for all food items, with, for example, a liquid crystal display (LCD), in place of the pushbuttons. In such case, for example, three pictorial icons, and three identifying words could be provided on the LCD display. Thus, each time that a user turns the switch, the LCD display would let the user scroll through these icons. The function of the food select is therefore to set the type of food, and thereby after the heating time set by the microprocessor. 
     Thus, the toasting time is a function of, for example, line voltage, cavity temperature sensed via a thermistor  81  in toasting chamber  22 , the darkness control setting, the food select setting, the warm setting and the frozen setting. At the end of the toast time, electromagnet  80  is de-energized, allowing the power to be removed from heating elements  28 , and toast lever  62  to be released. 
     Generally, switch settings are selected prior to the star of a toasting operation. However, if a different pushbutton is depressed after a toasting operation has started, the toasting activity may be modified from that time point as if these new settings were made initially. 
     After a cycle is completed, the darkness setting and food select input information should be retained, unless changed by the user. The warm and the frozen selections should be reset, and the LEDs turned off after a completed cycle. 
     When toaster  10  has been unplugged from its source of power, and then is plugged in again, a toast default setting should be assumed with no other special function selected. 
     In operation, the food select, darkness setting, warm and frozen selections are made, for example, by rotary control knob  90  and pushbuttons  84 ,  85 ,  94 ,  96  and  98 , and then toast lever  62  is pushed down. Microprocessor  76  then energizes electromagnet  80  as soon as power contacts  72  are sensed closed. Microprocessor  76  determines the timing required based on, for example, the above selections, and whether this is the first, second, third or greater cycle, or alternatively, by the cavity temperature determined by thermistor  81  instead of the cycle counting. 
     For bagels, if the outer surface is set for heating as well, the bagel relay may be energized after a preset shortened time, for example, one-third of a cycle, to remove power from the outer ones of heating elements  28 . 
     Further, the darkness control LEDs  88  between the LED corresponding to the set darkness and the minimum light setting LED are turned on. These LEDs  88  will turn off one at a time from minimum darkness LED to the darkness or set point LED as time expires. When time has expired, only the set point LED co-responding to the desired darkness setting, is left on. The time interval for each LED turning off should closely relate to the percentage of time elapsed, that is, if five LEDs  88  are lit at the start, only three LEDs should remain at half the cycle time. 
     If an LCD display is provided, during the toasting cycle a single digit LCD displaying the darkness setting changes to a three digit LCD showing time remaining to the end of the cycle (in minutes and seconds) and counts down as time is expiring. The digit countdown should be related to the elapsed time. Also, in such case, there can be icons as to the different darkness settings. However, the darkness icon selected for the darkness setting does not count down, but remains at the darkness setting mode. When the toast cycle is complete, the digit display will revert back to the single digit darkness setting ( 1 - 7 ). 
     Further, it is preferable that at a preset time, for example, three seconds, prior to the end of a toasting operation, a piezo buzzer will sound for a preset time, for example, one second. At the end of the toast time, electromagnet  80  and the bagel relay are de-energized. 
     Having described exemplary embodiments of the present invention with reference to the accompanying drawings, it will be appreciated that the present invention is not limited to those precise embodiments, and that various changes and modifications can be effected therein by one of ordinary skill in the art without departing from the scope or spirit of the invention as defined by the appended claims.