Abstract:
A gas flow control and igniter switch assembly for a gas appliance includes a valve body having a stem, an igniter activating switch and a knob, wherein the igniter is activated upon depressing of the knob a predetermined distance. The igniter switch is preferably constituted by a multi-piece outer casing within which is mounted multiple igniter contacts, an electrical connector, and an activating member. The activating member carries the electrical connector and is biased to a position which maintains an electric circuit to the igniter open. The multi-piece outer casing is adapted to be snap-fittingly secured together and mounted about the stem of the valve. Preferably, the stem extends freely through the outer casing but press-fittingly receives the activating member such that the activating member moves in axial unison with the stem. A knob is employed for rotating the stem to regulate the flow of gas from an inlet to an outlet of the valve, while also permitting the valve stem to be depressed in order to initiate a sparking operation at an electrode for a respective gas burner of the appliance.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the art of gas appliances and, more particularly, to a switching device, incorporated in an overall gas flow control valve assembly, for activating an igniter for the flow of gas. 
     2. Discussion of the Prior Art 
     In a gas appliance, such as a range, it is common to provide a plurality of gas burner elements to which gas is supplied through respective flow control valves. Typically, each valve is provided with a knob which is exposed at the front of the appliance and can be rotated to regulate the flow of gas to a respective burner. In years past, a pilot light was provided to ignite the regulated flow of gas. In order to avoid the need to maintain a constantly lit pilot light, it has now become commonplace to provide an electric ignition system for the gas, with the ignition system including an electrode provided at the burner element and an electric switch controlled by movement of the knob to develop a series of sparks at the electrode. In general, when the knob is rotated, an initial high gas flow/ignition position is reached wherein a cam inside the switch causes contacts to become electrically engaged. Once the gas is ignited, the user can rotate the knob further to terminate the sparking operation and to establish a desired flame setting. 
     With this arrangement, it is possible for the user of the appliance to release the knob while still in the initial position such that the igniter continues to unnecessarily spark. This circumstance is considered disadvantageous from various standpoints, including operational and economic inefficiencies. In addition, it would be advantageous to be able to initiate a sparking operation with the control knob in various rotational locations instead of only at an initial, rotational position. 
     Based on the above, there exists a need in the art for a valve and igniter switch assembly which is designed to automatically cease a sparking operation whenever an associated control knob is released. In addition, there exists a need for a valve and igniter switch assembly which will enable a user to initiate a sparking operation without requiring the knob to be in a specific operational position. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a gas flow control and igniter switching assembly for a gas appliance including a rotary valve body from which projects a control stem along an axially extending axis, with the stem being both rotatable about the axis to control a flow rate of gas through the valve and, preferably, shiftable in the axial direction relative to the valve body. In accordance with the most preferred embodiment of the invention, the switch portion of the assembly includes first and second contacts which become electrically engaged with each other upon shifting of the stem in the axial direction, substantially independent of the rotary angular position of the stem relative to the valve body. 
     In accordance with a preferred embodiment of the invention, the switch portion of the assembly includes an outer casing formed from first and second pieces which are snap-fittingly interconnected. The first and second contacts are seated in respective portions of the first casing piece. Interposed between the casing pieces is an activation member which is generally in the form of a disk. Attached to the activation member is an electrical connector which, in the most preferred form of the invention, is constituted by a spring member that abuts the first casing piece and biases the activation member towards the second casing piece. The first and second casing pieces, as well as the activation member, are provided with respective holes through which the stem passes. The hole in the first casing piece actually extends about a sleeve projecting from the valve body in order to non-rotatably mount the first casing piece to the valve body, while the stem is frictionally held in the bore of the activation member. A control knob is attached to the end of the stem for selectively rotating and axially shifting the stem. 
     With this arrangement, the activation member shifts axially in unison with the stem and relative to the contact members. Depressing the knob causes the activation member to electrically interconnect the contacts to initiate a sparking operation for igniting a supply of gas flowing through the valve. Since the activation member is biased away from the first casing piece and the contacts, releasing the control knob will automatically cause the electrical connector to become spaced from the contacts to terminate the sparking operation. The particular configuration of the contacts and the electrical connector establishes a wide range of angular positions for the knob in which the sparking will occur upon depression of the stem. In the most preferred form of the invention, the sparking can be activated throughout substantially the entire range of rotation of the stem. 
     Additional objects, features and advantages of the invention will become more fully apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is perspective view of a gas range incorporating the valve and igniter switch assembly of the invention; 
     FIG. 2 is an exploded view of the valve and switch assembly constructed in accordance with the present invention; 
     FIG. 3 is a side view of the valve and switch assembly shown in an off state; 
     FIG. 4 is a side view, similar to that of FIG. 3, depicting a control knob and actuating stem of the valve and switch assembly in a partially depressed, igniter activating position; 
     FIG. 5 is a side view, similar to that of FIG. 4, but depicting the control knob and actuating stem in a fully depressed and partially rotated position; 
     FIG. 6 is a side view, similar to FIG. 5, but depicting the valve and switch assembly in a normal operating position; 
     FIG. 7 is an enlarged perspective view of the switching device incorporated in the valve and switch assembly of FIG. 2; 
     FIG. 8 is an exploded view of the switching device of FIG. 6; and 
     FIG. 9 is a cross-sectional view of the switching device of FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With initial reference to FIG. 1, a gas range  2  is depicted incorporating the valve and igniter switch assembly  5  of the present invention. As shown, gas range  2  includes a cabinet  8  and a cooktop  11 . Cooktop  11  is formed with various recessed wells  12  within which are mounted gas burner elements. Extending over gas burner elements  15 ,  16  and  17 ,  18  are respective grates  20  and  21 . In general, each of the gas burner elements  15 - 18  are preferably of the sealed type and is adapted to receive a gas/air mixture which flows through circumferentially spaced ports and which is ignited through the use of a spark electrode. As this structure is widely known in the art and not considered part of the present invention, it will not be discussed in further detail here. Instead, reference is made to U.S. Pat. No. 5,152,276 directed to such a known type of seal gas burner assembly, with the disclosure in this patent being incorporated herein by reference. 
     Gas range  2  is also shown to include a control panel  28  that includes a display  30 , a row of function buttons  33  which are used to select a desired cooking operation within an oven located behind door  37  of gas range  2 . For instance, the first row of buttons  33  could be used to select between baked, broiled, clean and keep warm modes of operation. Control panel  28  is also shown to include a light button  39 , a cancel button  40 , an auto-set button  42  used in programming gas range  2 , a timer button  43 , cook and stop time buttons  45  and  46 , a numeric array  48  and a clock setting button  50 . In general, the arrangement and operation of control panel  28  is merely presented here for the sake of completeness and is not an aspect of the present invention. Also for the sake of completeness, gas range  2  is shown to include a lower drawer  52  which can be used to hold pans and the like in a manner known in the art. 
     In general, gas range  2  is depicted to illustrate an exemplary cooking device to which the valve and igniter switch assembly  5  of the invention can be applied. As will become more fully evident below, the valve and igniter switch assembly  5  of the invention can be used in connection with various different types of appliances and in other environments wherein it is desired for a user to control a flow of gas and the ignition of that gas. Reference will now be made to FIG. 2 in describing the main components of the valve and igniter switch assembly of the invention. 
     As shown in FIG. 2, valve and igniter switch assembly  5  includes a valve unit  65  having a body  67  provided with a gas inlet  69 , about which is provided a seal  70 , and a gas outlet  71 . Although not shown, valve body  67  houses a rotary valve that is interconnected to a stem  78  of valve unit  65 . Actually, this basic structure and operation of valve unit  65  is known in the art wherein stem  78  can be rotated to cause movement of an internal valve element in order to adjust the flow rate of gas supplied to inlet  69 , through body  67  and gas outlet  71 . As shown, stem  78  preferably includes an elongated cut-out portion  80 . Stem  78  is preferably supported on body  67  through the use of a plate  83  that is attached with threaded fasteners  85  and  86  to body  67 . Plate  83  includes a central sleeve portion  88 , through which stem  78  projects, and a hole  90 . Again, aside from the incorporation of valve unit  65  in the overall valve and igniter switch assembly  5  of the invention, the actual construction and operation of valve unit  65  is known in the art and, in fact, is utilized in various gas ranges currently available on the market today. 
     FIG. 2 also shows a switch assembly  92  constructed in accordance with the present invention. In accordance with the most preferred embodiment, switch assembly  92  includes an outer casing  94  which is defined by a first piece  96  and a second piece  98 . Details of switch assembly  92  will be discussed more fully below with particular reference to FIGS. 7-9. Valve and igniter switch assembly  5  also includes an indicator cover  104  including first, second and third diametric portions  106 - 108 . Third diametric portion  108  includes a face portion  111  that is preferably provided with various indicia used to aid a user in establishing a desired flow of gas through valve unit  65 . As shown, face portion  111  includes off, high and low positions, as well as representations of reduced flame sizes between the high and low positions. Third diametric portion  108  is interconnected with second diametric portion  107  through a side wall  112  such that indicator cover  104  defines a recessed area  113 . Indicator cover  104  is also preferably provided with a pair of diametrically opposed projections, one of which is indicated at  114 , which are adapted to be received in respective alignment holes  117  and  118  formed in second piece  98  of outer casing  94  of switch assembly  92 . Indicator cover  104  also includes a central bore  120 . 
     Finally, valve and igniter switch assembly  5  includes a knob  122 . Although knob  122  can take various forms, the preferred embodiment shown illustrates the presence of a sleeve portion  124 , a disk portion  127  and a handle portion  129 . Disk and handle portions  127  and  129  are provided with alignment markings  132  and  133  which are adapted to cooperate with the indicia provided on indicator cover  104 . 
     FIG. 3 illustrates an assembled state for valve and igniter switch assembly  5 . In this figure, indicator cover  104  has not been included for clarity purposes. The actual mounting of the various components of valve and igniter switch assembly  5  will become more fully apparent below after detailing the preferred construction of switch assembly  92 . However, at this point, it should be noted that interconnecting a valve unit, switch assembly, indicator cover and control knob for use in regulating a flow of gas and controlling the activation of a spark igniter is known in the art. Therefore, it is the particular construction and operation of switch assembly  92  in this overall arrangement which distinguishes the present invention from the known prior art. 
     Based on the above, reference will now be made to FIGS. 7-9 in describing the preferred construction and operation of switch assembly  92 . As shown, first piece  96  of outer casing  94  includes a first outer diametric portion  145  which is connected to a second outer diametric portion  146  through a radial portion  147 . First diametric portion  145  includes a central opening  148  and a pair of peripherally spaced slots  149  and  150 . At second diametric portion  146 , first piece  96  is provided with a plurality of radial protrusions  152 - 154 , each of which is provided with a respective axial opening  156 . Switch assembly  92  also includes first and second contacts  160  and  161 . More specifically, first contact  160  preferably includes an arcuate segment  163  and a linear segment  164  which defines a first electrical terminal. First contact is also formed with a tab  166  that is provided with an aperture  167 . The second contact  161  is defined by an arcuate segment  169  and a linear segment  170  that defines a second electrical terminal. The second contact  161  is also provided with a pair of spaced tabs  172  and  173  each of which includes a respective aperture  174  and  175 . As perhaps best shown in FIG. 8, first piece  96  of outer casing  94  is provided with an annular groove  177  along with various spaced posts, one of which is indicated at  178 . First and second contacts  160  and  161  are positioned within respective portions of annular groove  177 , with apertures  167 ,  174  and  175  each receiving a respective post  178 , and with linear segment  164  of first contact  160  projecting through slot  149 , while linear segment  170  of second contact  161  projects through slot  150 . In this manner, first and second contacts  160  and  161  are seated within first piece  96  of outer casing  94 . When seated, first and second contacts  160  and  161  do not engage each other. Linear segments  164  and  170  are adapted to be respectively interconnected to an incoming electrical source and to an, electrode of a respective gas burner element  115 - 118 . Therefore, with this arrangement, power to the electrode for initiating a sparking operation can be performed by electrically interconnecting first and second contacts  160  and  161 . 
     Switch assembly  92  further includes an electrical connector  181  which, in the most preferred embodiment, takes the form of a metal spring having an annular body  183 . Stamped from annular body  183  are a plurality of angled, resilient biasing legs  185 - 187 . Annular body  183  also includes a plurality of contact legs  190 - 192  which are generally L-shaped in side-view. As shown, biasing legs  185 - 187  are preferably arranged at an outer peripheral portion of annular body  183 , while contact legs  190 - 192  are arranged at an inner peripheral portion. Arranged preferably radially inwardly of each of the various biasing legs  185 - 187  is a respective protrusion  195  that is provided with a through hole  196 . 
     Switch assembly  92  also includes an activating member  201  having a first diametric portion  204  and a second diametric portion  205  interconnected by a radial section  207 . Projecting axially from radial section  207 , within the confines of first diametric portion  204 , are various bosses  210 - 212 , each of which includes a respective projecting post  214 - 216 . Each post  214 - 216  is adapted to be frictionally received within a through hole  196  of a respective protrusion  195  such that electrical connector  181  is seated upon bosses  210 - 212  and frictionally retained within the confines of first diametric portion  204  of activating member  201 . First diametric portion  204  of activating member  201  is actually received within the confines of second diametric portion  146  of first casing piece  96  as clearly shown in FIG.  9 . In this position, biasing legs  185 - 187  rest upon a ledge  219  defined by radial portion  147 . With this arrangement, biasing legs  185 - 187  tend to maintain the terminal ends of contact legs  190 - 192  at a position spaced from arcuate segments  163  and  169  of first and second contacts  160  and  161  as shown in FIG.  9 . However, depression of activating member  201  relative to first and second pieces  96  and  98  of outer casing  94  through second diametric portion  205  will cause biasing legs  185 - 187  to deflect which, in turn, will enable contact legs  190 - 192  to abut a respective one of arcuate segments  163  and  169 . When in this position, an electrical circuit between first and second contacts  160  and  161  is completed. 
     Second casing piece  98  of switch assembly  92  is provided with various outer peripheral tabs  222 - 224  which, upon seating of first and second contacts  160  and  161  and the positioning of both electrical connector  181  and activating member  201  within first casing piece  96 , can each be aligned with the opening  156  providing in a respective protrusion  152 - 154  in order to snap-fittingly interconnect first and second pieces  96  and  98  while containing first and second contacts  160  and  161 , electrical connector  181  and activating member  201  therebetween. FIGS. 2,  7  and  9  therefore show the fully assembled condition for switch assembly  92 , the components of which, in the preferred embodiment, are formed of molded plastic, with the exception of metallic contacts  160 ,  161  and electrical connector  181 . 
     As perhaps best evidenced with reference to FIGS. 2 and 3, when switch assembly  92  is positioned upon stem  78 , a portion of stem  78  projects from second cover piece  98  in order to enable the mounting of knob  122  upon stem  78 . Second piece  98  is provided with a non-circular hole  229  (see FIGS. 2 and 7) which cooperates with the shape of stem  78  given the presence of elongated cut-out portion  80  wherein activating member  201  is frictionally retained by stem  78  for concurrent rotational and axial movement. A similar interconnection is made between sleeve  124  of knob  122  and stem  78 . On the other hand, stem  78  extends freely through central opening  148  of first casing piece  96 . More particularly, central opening  148  is defined, at least in part, by a resilient extension  233  (see FIG. 9) which has formed thereabout various radially inwardly projecting and circumferentially spaced mounting segments  235 . With this construction, when switch assembly  92  is placed over stem  78 , first casing piece  96  is tightly mounted about sleeve  88 . Although not shown, first casing piece  96  could be formed with an indentation to receive the head of one or more of fasteners  85  and  86  to further aid in locating switch assembly  92  for non-rotational movement relative to valve body  67 . In any event, outer casing  94  is fixed against rotation relative to valve unit  65 , along with indicator cover  104  and first and second contacts  160  and  161 . On the other hand, activating member  201  and electrical connector  181  rotate in unison with stem  78  as controlled by the manual manipulation of knob  122 . 
     FIGS. 3-6 show various operational positions of the valve and igniter switch assembly  5  of the present invention. As indicated above, FIG. 3 simply illustrates an assembled condition wherein the valve unit  65  is closed to prevent the flow of gas from inlet  69  towards outlet  71 . Again, it should also be noted that indicator cover  104  is not shown in these figures for clarity purposes. In a manner known in the art, stem  78  actually terminates within valve body  67  in a plate  252  which is connected by a spring  254  to the actual rotary valve element within body  67 . Again, this particular operation for valve unit  65  is known in the art. However, this arrangement enables a detent configuration to exist which requires a depression of knob  122  and a corresponding axial shifting of stem  78  to the position shown in FIG. 5 in order for knob  122  to be rotated out of the “off” position. That is, plate  252  is formed with a tab  258  which is received within hole  90  in the position of FIG.  3  and stem  78  must be depressed a distance to clear tab  258  from hole  90 . In general, stem  78  can shift in the order of {fraction (3/32)}″ from the FIG. 3 position to the FIG. 5 position. Prior to reaching the FIG. 5 position, contact legs  190 - 192  will engage arcuate segments  163  or  169  such that electrical current is supplied to the electrode at a respective gas burner element  15 - 18 . For instance, contacts  160  and  161  are electrically connected at the position shown in FIG. 4, e.g., upon a {fraction (2/32)}″ (0.16 cm) shifting of stem  78 . Therefore, whenever knob  122  is axially depressed to at least the position shown in FIG. 4, activating member  201  will be shifted relative to outer casing  94  of switch assembly  92  by the deflection of biasing legs  185 - 187  to enable contact legs  190 - 192  to engage a respective arcuate segment  163 ,  169  of first and second contacts  160  and  161 . In this position, first and second contacts  160  and  161  will be electrically interconnected to initiate a sparking operation at the respective gas burner element  15 - 18 . Once the user releases knob  122  such that the knob  122  again shifts to the axial position shown in FIG. 6 wherein stem  78  remains deflected only a slight amount, such as {fraction (1/32)}″ (0.08 cm), electrical connector  181  will no longer complete a circuit with first and second contacts  160  and  161 . Although knob  122  and stem  78  can be continually rotated, such as through approximately 270°, in order to select a desired gas flow rate and corresponding flame size for cooking purposes, the ignition circuit will not be closed unless stem  78  is further depressed through knob  122 . In the FIG. 6 position, tab.  258  preferably extends in a groove (not shown) formed in a rear portion of plate  83 , with the groove leading from hole  90  to define the permissible extent of travel for knob  122 . 
     It should be readily apparent that, unlike the prior art which established a predetermined igniter position between “off” and “high” settings, the igniter circuit associated with the present invention can be closed at a wide range of positions by simply depressing of knob  122  a predetermined extent. The axial deflection of activating member  201  occurs, in the most preferred embodiment, since non-circular hole  229  receives stem  78  in a generally press-fit manner such that any axial shifting of stem  78  will result in a corresponding axial shifting of activating member  201 . In any event, it should also be noted that it is not possible for a user of gas range  2  to inadvertently leave valve and igniter switch assembly  5  in a continued sparking position. In the most preferred form of the invention, the use of three contact legs  190 - 192  enables the igniter to be activated regardless of the angular position of knob  122 . Of course, it would be possible to limit the particular angular range (approximately 270° in the preferred embodiment), such as by simply limiting the length of arcuate segments  163  and  169 , the number of contact legs  190 - 192  or the like. The manner in which switch assembly  92  can be pre-assembled through the snap-fit interconnection of first and second pieces  96  and  98  of outer casing  94  advantageously enables pre-assembling of switch assembly  92  for subsequent interconnection with the various other components of valve and igniter switch assembly  5 . Any maintenance of switch assembly  92  is also enhanced versus the prior art wherein switch housings are typically riveted or otherwise sealed in a manner which would require the entire switching unit to be replaced following a detected malfunction. 
     Based on the above, it should be recognized that the valve and igniter switch assembly of the present invention provides an advantageous igniter control arrangement in a simple and effective manner. However, although described with respect to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, although first and second contacts  160  and  161  are fixed relative to first casing piece  94  and are adapted to electrically linked by connector  181 , other electrical arrangements including providing one of the contacts on activating member  201  would also be possible. Furthermore, although it is preferred to have activating member  201  both rotate and axially shift in unison with stem  78  and knob  122 , it would be possible to simply have activating member  201  axially shift with knob  122 , such as by having sleeve  124  of knob  122  directly abut a portion of activating member  201  to cause the desired axial shifting. In any event, the invention is only intended to be limited by the scope of the following claims.