Abstract:
The effective length of a control arm having manually alterable stops repositionable along is rendered automatically changeable by means of a solenoid movable strip arranged to be either pressed against the control arm or removed from contact with the control arm by operation of the automatically operated solenoid which may usually be operated by a change in the surrounding ambient temperature.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present utility application takes priority from U.S. Provisional Application Ser. No. 61/174,574 entitled, “Feed Regulator For Thermostatic Control” filed on May 1, 2009 in the name of George Kuzni. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to furnace and boiler stoker devices, and more particularly to an improved coal feed mechanism and control system for automatically regulating the amount of a fuel such as coal being fed to a furnace fire bed. 
     2. Preliminary Discussion and Discussion of Prior Art 
     With the price of fuels such as oil and gas continuing to rise, stoves and furnaces that use other less expensive fuels such as coal are becoming increasingly popular. Most coal stoves and furnaces include some type of stoker device or system for automatically feeding coal into the stove or furnace as needed. One such prior art device is described in U.S. Pat. No. 4,537,140 issued to Baker entitled “Automatic Coal Stove Stoker”.  FIG. 1  is a sectional view of the prior art Baker mechanical coal feeding mechanism, and shows a fire box in communication with a coal hopper in a usual manner, with the hopper floor sloping downwardly toward the fire box where it abuts against a similarly angled downwardly sloping perforated fire grate, so that coal in the hopper is caused by the force of gravity to slide or roll down the hopper floor through a restricted exit passage in the hopper onto the grate. In addition, as part of Baker&#39;s coal feed mechanism a linearly reciprocating slidable plate is provided on the floor of the coal hopper, which aids in advancing coal out of the hopper onto the grate. In effect, the reciprocating motion of the plate on the hopper floor in Baker enhances the gravity flow of coal out of the hopper. Such plate is operably connected to a motor via an eccentric movement means and a rod that extends through an aperture in a downwardly depending shoulder on the upper edge of the plate, which shoulder serves as a pusher bar. An end stop and a threadably adjustable stop are strategically positioned on the rod on opposite sides of the shoulder, so that movement of the rod by the eccentric movement means cause the plate to essentially be pushed back and forth in a reciprocating linear path on the hopper floor as the stops on the rod alternatingly engage against either the outer and inner sides of plate, respectively, with a pause in sliding movement for the duration of rod movement between the two stops. As the plate is urged rearwardly by the inner stop, coal in the hopper falls downwardly onto the floor of the grate into the space vacated by the front of the plate, so that when the plate is moved forwardly again the leading edge of the plate pushes or forces such coal out of the hopper into the fire box and grate. A fan to affect a forced draft upwardly through the grate to enhance burning is also provided. 
     While the Baker coal feed mechanism is suitable for its particular purposes, a drawback is that although the reciprocating plate stroke length can be varied to regulate at least somewhat the amount of coal being pushed into the fire box, and therefore the amount of heat produced, in order to adjust the linear distance the reciprocating plate moves, the position of the adjustable stop must be manually rotated either clockwise or counterclockwise on the threaded rod. Such manual adjustment procedure is limiting as well as inconvenient in today&#39;s modern society, since, for example, a homeowner may wish to decrease the amount of heat generated during daytime hours when no one is home, and then automatically increase the heat during morning or evening hours, which is not possible where only manual adjustment is achievable. Further, in order for a stoker-fed coal furnace to operate properly, there must be a sufficient fire in the furnace at all times to ensure combustion of the additional coal supplied by the stoker. It is known in other prior art coal stoker arrangements to additionally provide a thermostat or other temperature sensing device to automatically turn the power to the stoker motor on and off, thereby regulating the amount of coal burned and heat generated. A thermostat can also be used to activate the stoker at sufficiently short intervals to ensure that additional fuel will be called for before the fire has reached so low a level as not to be capable of igniting the fresh fuel. However, this frequently does not provide for sufficient regulation of room temperature, and is generally undesirable and ineffective particularly for relatively single stoker systems for coal stove-type devices and the like. 
     The present inventor, recognizing the limitations inherent in previous coal stoker equipment, has devised a surprisingly efficient and effective arrangement for periodically adjusting or regulating the distance a linearly reciprocating plate such as those used in the Baker type stoker feeding mechanisms travels, which provides significantly improved thermostatic control of the amount of fuel that is forced into the fire box and also as a result the temperature of a room or interior building space. The present invention can also be used with other types of mechanical stoker systems wherein a mechanical reciprocating pusher is utilized. For example, U.S. Pat. No. 4,662,290 issued to Potts entitled “Automatic Coal Stoker” discloses a pusher assembly having a slidingly reciprocating rectangular box configuration with a cam inside, wherein rotation of a cam imparts a reciprocal sliding motion to a pusher assembly. The present invention can also be used to automatically regulate the operation of the Potts coal stoker, rather than having to manually turn the stroke adjusting screw or change the size of the cam. U.S. Pat. No. 6,647,091 issued to Somers entitled “Automatic Coal Stoker” is an example of another similar assembly but having a substantially horizontal fire grate with which the present invention can also be utilized. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to provide a feeder mechanism capable of allowing automatic and external adjustments for the amount of a fuel such as coal that is fed into a stoker type furnace or boiler utilizing a linearly reciprocating plate to enhance the gravity flow of coal to said furnace. 
     It is a further object of the present invention to provide a device for automatically adjusting the linear distance said reciprocating plate moves at least temporarily, allowing the amount of fuel being fed onto a fire grate to be increased to regulate the temperature in an area. 
     It is a further object of the present invention to provide a thermostat control for temporarily varying the stroke length of a linearly reciprocating plate type stoker furnace mechanism. 
     It is a still further object of the present invention to provide a system for automatically varying the amount of fuel being fed into a furnace by a stoker device by at least temporarily adjusting the linear distance a reciprocating plate forming part of the feeding mechanism of the stoker device slidingly moves on the floor of a coal bin. 
     It is a still further object of the present invention to provide a thermostatic control for a coal feed mechanism that can be retrofitted into existing coal burning furnaces and boilers. 
     It is a still further object of the present invention to provide a relatively simple yet effective means for increasing the effectiveness and control of operations of a linearly operable stoker mechanism for feeding fuel in a stoker type coal stove or furnace feed which provides additional adjustability of response at predetermined times. 
     Still other objects and advantages of the invention will become clear upon review of the following detailed description in conjunction with the appended drawings. 
     SUMMARY OF THE INVENTION 
     The operation of a manually adjustable sliding plate type motor stoker is improved by the use of a simple temperature or time indexed adjustment for the sliding plate induced by moving a solenoid arm into the path of movement of an adjustment mechanism for the sliding plate movement indexer so as to in effect lengthen the path of movement of the sliding plate feeder mechanism, thereby feeding relatively more coal into the burning grate by the length and path of movement of the sliding feed plate. 
    
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         FIG. 1  delineated as prior art is a sectional view from the side of a prior art stoker arrangement. 
         FIG. 2  is a side view of a stoker arrangement of a type used with the present invention. 
         FIG. 3  is a partial isometric view of the control system for use with the coal stoker arrangement shown in  FIG. 2 . 
         FIG. 4  is a partial side view of the control system shown in  FIG. 2  with the spacer bar in a first pivoted position. 
         FIG. 5  is a partial side view of the control system shown in  FIGS. 2 and 3  with the spacer bar in a second pivoted position. 
         FIG. 6  is a partial isometric view of the control system in combination with the reciprocating rod assembly and illustrative thermostat control. 
         FIG. 7  is a partial isometric view of the control system and reciprocating rod assembly with the spacer bar in the first pivoted position shown in  FIG. 4  and the reciprocating rod moved so that the adjustable stop is adjacent the inner surface of the plate angled shoulder section. 
         FIG. 8  is an oblique drawing of the operating mechanism of a further type of sliding plate mechanism. 
         FIG. 9  is an oblique more complete view of the portion of the apparatus show in  FIG. 8  but also showing the sides of the hopper plus the opening in the top through which the coal drops into such hopper. 
         FIG. 10  is an oblique view similar to  FIG. 9  in which the rotatable arm has turned further and is displacing the stop which has been started in its outward movement by the set screw. 
         FIG. 11  is a view of an improved arrangement according to the invention in which a setting nut has been provided which is adjustable on a setting rod, and including the solenoid activated spacer bar of the invention. 
         FIG. 12  is a further view similar to  FIG. 11  in which the spacer bar of the control system is in a first, nondeployed position. 
         FIG. 13  is further view similar to  FIG. 11  in which the spacer bar of the control system is in a second, activated position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description is of the best mode or modes of the invention presently contemplated. Such description is not intended to be understood in a limiting sense, but to be an example of the invention presented solely for illustration thereof, and by reference to which in connection with the following description and the accompanying drawings one skilled in the art may be advised of the advantages and construction of the invention. 
     The present invention is directed to an improvement in an automatic coal stoker device of a type having a pusher assembly in which a linearly reciprocating panel is positioned overlying the bottom wall or floor of the coal hopper, as well as related arrangements. The reciprocating panel is connected to a motorized rod which when activated effects such linear reciprocating motion. The back and forth movement of the panel causes coal to be pushed out of the hopper by the forward edge of the panel into the furnace or coal burning area at a uniform rate. The rearward edge of the reciprocating panel extends out of the hopper through a slot in a sidewall of the coal hopper, and a shoulder member on the rearward edge of the panel which serves as a pusher bar has an aperture through which the end of the motorized rod extends. Adjustable stops on the rod are positioned on opposite sides of the shoulder member, which stops alternatingly engage against the side surfaces of the shoulder as the rod reciprocates, pushing the panel slidingly outwardly on the coal hopper floor and then inwardly again a predetermined distance. Such basic arrangement is described in U.S. Pat. No. 4,537,140 issued to Baker heretofore described, the entirety of which is hereby incorporated by reference. The present inventor has now developed a control device which is preferably used in combination with a thermostat system with such coal stoking mechanism whereby the distance the linearly reciprocating panel moves back and forth on the floor of the coal hopper can be automatically adjusted. Such automatic adjustment allows for substantially improved automatic control or regulation of the temperature in a room, building space, or the like by temporarily increasing or decreasing the amount of coal that is pushed into the furnace burning area by the coal stoker, thereby regulating the amount of heat produced by the stove. The present inventor&#39;s system comprises a substantial improvement over prior art systems such as shown in Baker, wherein the only way to regulate the movement of the panel was to manually adjust the position of the stops on the reciprocating rod, which is inconvenient at best and impractical where the user wishes to automatically regulate the temperature during different parts or the day, or in response to natural changes in the outdoor or atmospheric temperature. 
       FIG. 1  illustrates the prior art mechanical coal stoker assembly of Baker,  FIG. 2  illustrates a related arrangement that is closely similar to Baker with some minor modifications,  FIGS. 3-7  illustrate a preferred embodiment of the present inventor&#39;s coal stoker system and assembly, and  FIGS. 8-13  illustrate another preferred embodiment of the present invention. In the several illustrated embodiments, wherever possible, like reference numerals have been used to denote like elements or like functional means. In addition, certain elements referred to in the embodiment shown in  FIGS. 2-6  may be illustrated in the embodiment shown in  FIG. 1 , which is a sectional side view of a conventional stoker, and is generally referred to by reference number  10 . Stoker assembly  10  includes a fire box or furnace  12  having downwardly sloping or inclined sidewalls  14  and supporting ramp sidewalls  16 , and a hopper  20  typically made of sheet metal, which is connected to the rear surface of a fire box or furnace  12 , partially shown. Hopper  20  has a downwardly sloping or inclined bottom wall or floor  68  which joins with a perforated fire grate in furnace  12 , and as described in greater detail below has appropriate sidewalls, a front wall, and a rear wall. A bin having a lid with a handle, not shown, is normally positioned on the open top of the hopper  20  and holds a supply of coal which is automatically fed into hopper  20  by gravity as coal in hopper  20  is passed into furnace  12  through restricted passage  62  in front side wall  102 . 
     As indicated above, floor  68  of hopper  20  is inclined downwardly towards furnace  12 , and extends inwardly into furnace  12  somewhat, and is directly adjacent a fire grate  66  which at least initially is positioned at the same downward slant or angle as floor  68  to allow for an even flow of coal from hopper  20  into furnace  12 . A fan or blower  30  is provided to pass a continual flow of air into the furnace to aid in the combustion process, which fan is connected to a motor, not shown. 
     A flat pusher plate  46  is positioned resting on floor  68  of hopper  20 , which plate is preferably made of sheet steel. Pusher plate  46  has a leading edge  110  and as shown in  FIG. 12  a rearward edge  112 , as well as a top surface  41  on which coal in hopper  20  rests, and a bottom surface  42  which is flush against floor  68  of hopper  20 . The rearward edge  112  of plate  46  extends out of hopper  20  through slot  48  in rear wall  108  of the hopper  20 . Shoulder or angled section  50  extends downwardly from the rearward edge  112  of plate  46 , and there is an aperture  52  provided in shoulder  50  through which, as explained in greater detail below, the distal end of threaded rod  40  is passed. 
     As shown in  FIG. 2 , threaded rod  40  has an elongated section  118  and a shorter angled section  120 , which shorter angled section  120  is connected to a motor  28  by linkage assembly  31 . Linkage assembly  31  forms essentially a reciprocating mechanism which is coupled to motor  28  and adapted for converting rotational motion provided by the motor  28  into reciprocating linear motion, and as shown linkage assembly  31  is cam-type connector wherein as said cam connector is moved in an endless path the elongated section  118  of rod  40  is caused to reciprocate linearly. It will be understood that numerous mechanisms known to those skilled in the art for converting rotary motion of a motor into a reciprocating motion may be substituted for the presently described linkage assembly. Linear reciprocating movement of the elongated section  118  of threaded rod  40  urges the outer or distal end of elongated section  118  linearly back and forth through aperture  52  in shoulder or pusher plate  50  of reciprocating plate  46 . An end stop  54  is provided on the outer end of elongated section  118 , while a threadably adjustable stop  58  is provided on elongated section  118  of rod  40  at a position inwardly of the inner surface  122  of shoulder member  50 , and which stops  54  and  58  are dimensioned so that they cannot pass through aperture  52 . Adjustable stop  58  in  FIG. 2  has a handle section which due to gravity hangs downwardly on the threads of elongated rod section  118 , preventing the stop from rotating on such threads. 
     Reciprocating movement of elongated section  118  of rod  40  caused by motor  28  includes an outbound stroke and an inbound stroke. During the outbound stroke, section  118  of rod  40  moves outwardly until at some point depending on the position of stop  58 , the outer surface of such stop  58  will press against the inner surface  122  of shoulder member  50 . Continued movement of rod section  118  in an outbound direction causes stop  58  to push shoulder member  50  outwardly, and as a result also pushes plate  46  on the floor  68  of hopper  20  outwardly or away from furnace  12 . Such outward movement creates a space in hopper  20  forward of the leading edge  110  of plate  46 , which space is quickly filled by coal in hopper  20  falling or moving downwardly by the downward force of gravity as well as the forwardly inclined angle of bottom surface or floor  68  of hopper  20 , filling such space. 
     Eventually, rod section  118  of rod  40  will finish its outward stroke and begin its return or inward stroke, and at some point depending on how far outwardly shoulder member  50  and plate  46  are pushed, end stop  54  will engage against the outer surface of shoulder or pusher plate  50 . This in turn causes panel  46  to also be pushed forwardly towards furnace  12  on the floor  68  of hopper  20 , which movement will push coal that has filled the space in front of the leading edge  110  of panel  46  into furnace  12 , where it is burned for heat. At certain points between rod  40  completing its outward stroke and starting its inward stroke, panel  46  will remain motionless until rod section  118  and end stop  54  are moved far enough inwardly again to come into contact with the outer surface of shoulder  50 . Similarly, upon completion of the inward stroke panel  46  will remain motionless at a full inward position until the reciprocating motion of rod  40  has reversed and has once again traveled outwardly a sufficient distance for adjustable stop  58  to again press against the inner surface  122  of shoulder  50 , where the outward motion of plate  46  is repeated. 
     The distance that panel  46  is pushed outwardly can be varied manually simply by turning and adjusting the position of adjustable stop  58  on the threads of elongated rod section  118  of rod  40 . For example, rotating stop  58  in a counterclockwise direction when viewed from end stop  54  will move it farther away from shoulder  50  connected to plate  46 , which will cause such stop  58  to contact the inner surface  122  of shoulder member  50  at a later time upon each outward stroke of rod section  118 , and as a result, stop  58  will be engaged against inner surface  122  of shoulder member  50  for a shorter time period and move plate  46  on the floor  68  of hopper  20  a shorter distance. The shorter the distance that plate  46  is moved outwardly, the less room or space is created along the leading edge  110  of the plate  46  for coal to fill, so that on the return or inward stroke, less fuel is subsequently pushed by leading edge  110  into the furnace. Alternatively, if stop  58  is rotated in a clockwise direction when viewed from end stop  54 , upon each outbound stroke of rod section  118 , stop  58  will contact the inner surface  122  of shoulder member  50  sooner, and thus will push plate  46  outwardly a greater distance, leaving more space along the leading edge  110  of panel  46  in hopper  20  for coal to fill, which greater amount of coal will be pushed into furnace  12  on the return stroke, causing the stove to emit more heat. 
     As indicated,  FIGS. 1-2  illustrate the basic type of stoker arrangement from which the present invention is designed as an improvement and can be readily adapted to use therewith. However, the Baker type furnace has spawned a number of variations based upon the same basic mechanical arrangements and the present applicant has chosen to use some of such later variations for illustration of his invention. 
     As discussed above, the stoker assembly includes a coal hopper  20  typically made of sheet metal, which is connected to the rear surface of a fire box or furnace  12 , partially shown. More particularly, hopper  20  has a front wall  102 , sidewalls  104 , and a rear wall  108 , and a downwardly sloping or inclined floor  68  which abuts end to end with perforated fire grate  66  in furnace  12 . Bin  21  (see  FIG. 2 ) is positioned on the open top of hopper  20  and holds a supply of coal which by force of gravity is automatically fed into hopper  20  as coal in hopper  20  passes into furnace  12  through passage  62  in front wall  102 . Downwardly inclined floor  68  of hopper  20  extends inwardly into furnace  12  to grate  66 , which grate  66  at least initially has the same downward slant or angle to allow for an even flow of coal from hopper  20  into furnace  12 . Fan or blower  30  is connected to a motor  28 , which motor may be an electrical motor, and passes a continual flow of air across grate  66  in furnace  12  to aid in the combustion process. 
     Flat pusher or reciprocating plate  46  is positioned resting on floor  68  of hopper  20 , which plate  46  is preferably made of sheet steel. Plate  46  has a forward or leading edge  110  (see  FIG. 1 ) and a rearward edge  112  (see  FIG. 2 ), as well as a top surface  114  on which coal in hopper  20  rests, and a bottom surface  116  which is flush against floor  68  of hopper  20 . The rearward edge  112  of plate  46  extends out of hopper  20  through slot  48  in rear wall  24  (see  FIG. 1 ). Angled shoulder or pusher plate  50  extends downwardly from rearward edge  112  of plate  46 , and an aperture  52  is provided in angled plate  50 , through which, as will be explained in greater detail below, the distal end of threaded rod  40  is passed. 
     Referring now in particular to  FIGS. 3-6 , there is shown a thermostat control system  70  for automatically adjusting the distance plate  46  is moved outwardly during the outbound stroke of motorized reciprocating rod  40 . System  70  provides users with significantly greater and easier control of the amount of heat being produced by devices such as coal stoker device  10  during any given time period, thus increasing the user&#39;s selective control over the temperature in a room, home, or other indoor area in which the coal stove is located. The inventor accomplishes this by providing a thermostatically controlled arm or spacer bar  72 , which is selectively inserted in the space between the outer surface  126  of threaded stop  58  and the inner surface  122  of angled plate  50 . This in effect lengthens the setting of the stop  58  and lengthens the stroke of the plate  46  and the distance such plate is moved outwardly, allowing more coal to be dropped in front of it from the hopper and increasing the feed of coal into the system on the backstroke. 
     Referring now to  FIG. 3 , there is shown a portion of the underside  116  of plate  46 , and of the inner surface  122  of downwardly disposed angled plate  50  connected to the rearward edge  112  of plate  46 , and showing aperture  52  in angled plate  50 . Spacer bar  72  has a curved blade section  78  and a flat section  80 , and is pivotally mounted to the inner surface  122  of angled plate  50  on pivot member  76 . Spacer bar  72  is aligned so that in a first pivoted position, blade section  78  is pivoted upwardly or away from aperture  52  (see  FIG. 4 ), and in a second pivoted position blade section  78  is disposed in close proximity to or in front of aperture  52  (see  FIG. 5 ). Flat section  80  of spacer bar  72  extends outwardly in the opposite direction from blade  78 , and a counterweight  82  is provided on the outer end of flat section  80 . 
     In addition, a small electric solenoid  84  is mounted to the inner surface  122  of angled plate  50  in a conventional manner such as by screws, straps, or the like, in a position adjacent flat section  80  of spacer bar  72 . A plunger  86  extends through an orifice in the side surface of flat section  80  of spacer bar  72 , where it is secured by plunger head  88 . In addition, a stop  85  is positioned under head  88 , which as explained below prevents spacer bar  72  from pivoting beyond a predetermined angle in the first pivoted position shown in  FIG. 4 . Solenoid  84  is of a type well known in the prior art for converting electrical energy into linear motion. A suitable commercially available solenoid for use with the present invention would be a small size, open frame solenoid of a type having a plunger weight of 2.4 grams and a total weight of 18 grams, dimensions of 24 millimeters by 16 millimeters by 13 millimeters, and power consumption during continuous use of 1.6 watts, operating with 6 volts. However, the above specifications should not be considered limiting, and solenoids having other specifications or linear or rotary solenoids may be utilized with the present invention. Plunger  86  is pulled upwardly towards solenoid  84  when the solenoid is energized, and is released when the solenoid is deenergized. As illustrated in  FIGS. 3 and 4 , solenoid  84  is in a deenergized state, so that plunger  86  is extended from solenoid  84 . Spacer bar  72  is mounted on pivot  76  so that counterweight  82  will cause spacer bar  72  to pivot into said first pivoted position, wherein as shown in  FIGS. 3 and 4  blade section  78  of spacer bar  72  is pivoted upwardly away from aperture  52 . However, as illustrated in  FIG. 5 , when electric solenoid  84  is energized, plunger  86  is pulled inwardly towards the solenoid so that plunger head  88  is no longer resting on stop  85 , and which movement causes flat section  80  of spacer arm  72  to be pivoted upwardly on pivot  76 , while blade section  78  of spacer arm  72  pivots downwardly so the blade section  78  is in front of at least a portion of aperture  52 . 
     As best shown in  FIG. 6 , system  70  also includes a thermostat control  90 , which is operably connected to solenoid  84  in a known manner, such as by a hardwire connection or a wireless controller, and is used to selectively energize the solenoid. Thermostat  90  includes a display area  94 , on which in the example shown in  FIG. 6  the room temperature  96  is indicated as being 66 degrees, while the desired temperature  98  indicated is 68 degrees. In such circumstance, it is desired to increase the amount of heat being produced by furnace  12  to raise the room temperature from 66 degrees to 68 degrees, and therefore the amount of coal being introduced into furnace  12  must be increased at least temporarily until the desired room temperature is reached. In order to increase the amount of coal being introduced into furnace  12 , the distance plate  46  is moved outwardly of coal hopper  20  must be increased. While in previous arrangements described above, this could only be accomplished by adjusting the position of stop  58  by use of a manual operation or by some complicated mechanical arrangement, through use of the present inventor&#39;s thermostat control system  70 , this is accomplished simply and effectively by having blade section  78  of spacer bar  72  pivot downwardly into a second pivoted position so that blade section  78  is interposed between the outer or forward facing surface  126  of adjustable stop  58  and the inner surface  122  of angle blade  50 . Thus, when as shown in  FIG. 6  reciprocating rod section  118  of rod  40  moves in an outbound stroke in a manner that has already been described, blade section  78  of spacer bar  72  will be wedged in-between stop  58  and the angled plate  50 , in effect causing stop  58  to commence pushing against inner surface  122  angled plate  50  earlier than otherwise, causing plate  46  in hopper  20  to start moving outwardly sooner during such outbound stroke, and as a result pushing plate  46  a further distance rearwardly out of hopper  20 . Spacer bar  72  is thus automatically pivoted into such position when solenoid  84  is energized, which energization takes place whenever the set temperature  98  of thermostat control  90  is greater than the room temperature  96 . 
     In effect, therefore, by temporarily inserting blade section  78  of spacer bar  72  between stop  58  and the inner surface  122  of angled plate  50 , the linear distance or stroke length of the device is increased automatically. As should now be evident, insertion of blade section  78  between stop  58  and angled plate  50  causes reciprocating plate  46  to move a greater distance out of coal hopper  20 , thereby allowing more coal to fall downwardly into the space created along the leading edge  110  (see  FIG. 1 ) of plate  46 , and then upon an inbound stroke forcing more coal into furnace  12  and generating more heat. Once the actual temperature  96  in the room or other interior environment rises to the set temperature  98 , thermostat control  90  will automatically deenergize solenoid  84 , allowing blade section  78  of spacer bar  72  to pivot upwardly due to counterweight  82  so that it no longer is situated between stop  58  and angled plate  50 . Thus, as shown in  FIG. 7 , upon the next outbound movement of elongated rod section  118 , plate  46  will not commence moving outwardly until stop  58  abuts directly against inner surface  122  of angled plate  50 , and thus the stroke length or distance plate  46  is moved outwardly will be decreased to the original setting. 
     It will be evident from the above that thermostat control system  70  of the present invention comprises a substantial advance over the prior art system described with particular reference to  FIGS. 1 and 2 , wherein in order to adjust the stroke length of the stoker device, the position of stop  58  must be manually adjusted by rotating the stop in either a clockwise or counterclockwise direction on rod  40 . In the present arrangement, however, it is not necessary to manually adjust the position of stop  58 , since if the heat energy is to be increased, the user will simply utilize the thermostat control  90  accordingly so that solenoid  84  is energized to cause spacer bar  72  to pivot so that blade section  78  is between stop  58  and the inner surface  122  of angled blade  50  attached to plate  46 . It should also be evident that the width of blade section  78  may be varied accordingly, so that if blade  78  is wider it will be contacted by stop  58  sooner than if blade Th is narrower. In addition, the position of stop  58  may also still be manually adjusted to different base or standard positions, as may be desired to set a base heat level. For example, if a lower base temperature is desired, stop  58  may be turned or rotated clockwise from the perspective of stop  54 , or if a higher base temperature is desired, stop  58  may be turned or rotated counterclockwise from the perspective of stop  54 . The combination of adjustable stop  58  and the thermostat control system  70  allows for automatic and therefore significantly greater precision and control over the amount of fuel being introduced into coal stoker assembly  10  and as a result the amount of heat being produced and therefore the room temperature. Using thermostat control system  70 , the device can be programmed to automatically increase the stroke length of plate  46  at different times of the day, or simply to maintain the room or environment at a constant temperature as the atmospheric or outside temperature rises and falls, at least within a reasonable range. 
     Other reciprocating coal feeder mechanisms based on the Baker model whereby the reciprocating movements are produced in more than one way have been devised and are still in operation. A reciprocating movement is used for a variety of coal and pellet stoves, mostly following the same idea of having either a crank, producing the back and forth movement, or a concentric cylinder, or a rotating cam with a cam follower mechanism to produce the movement as well, and some newer models resort to having a windshield wiper like arrangement to produce an angular rather than a linear reciprocating movement. All movements mentioned herewith, still rely on either a manual adjustment to vary the stroke length of a travel distance, or on shutting off the motor and have wait time between cycles. 
     One such other arrangement is shown generally in  FIG. 8  and more fully in  FIGS. 9-10 . As in the previously described arrangement, a reciprocating plate  46  is situated on the top surface of downwardly sloping floor  68  of hopper  20 , with one end projecting through transverse slit  48  in the rearward end of hopper  20 , and with perpendicular or radially projecting plate  50  on the end of reciprocating plate  46 , which in the presently described embodiment is disposed in the upward direction. Bracket  35  is made up of side sections  32  and  34  joined on one end by cross section  38 , while the other ends of side sections  32  and  34  are welded to the back of perpendicular plate  50  extending outwardly therefrom to form a rectangular shape. In the present embodiment, plate  50  serves more than one function. Plate  50  prevents reciprocating plate  46  from sliding all the way down floor  68 , by abutting against plate  52  (see  FIG. 9 ) at the rear side of the hopper  20 . In addition, as explained in further detail below, plate  50  serves as the contacting surface for pushing reciprocating plate  46  during the dump stroke of the cycle by the bearing or the cam follower  40  attached at the end of crank arm  31  pivoting around the reduction gears point, at about 1 RPM, powered by motor  28 . 
     Plate  46  is moved in a reciprocating linear movement by the rotation of the crank arm  31  pivoting around the reduction gears point produced by motor  28 , and by having bearing or cam follower  40  engage alternatingly against the back side of plate  50  and movable and adjustable stop  57 , respectively, which stop  57  is secured to end section  38  of bracket  35  by sliding guides  64  made up of either shoulder bolts or other metal studs. Adjustable stop  57  has cutout sections on its ends which engage with sliding guides  64  so that stop  57  is free to slide along sliding guides  64 . Rotation of crank arm  41  causes plate  46  to be slidingly pushed and pulled back and forth on floor  68  of hopper  20 , with a pause in such a sliding movement of plate  46  for the duration of movement of bearing  40  between plate  50  and adjustable stop  57 . As plate  46  moves rearwardly, coal in hopper  20  falls downwardly onto floor  68  in front of plate  46 , and when the plate again is moved forwardly the leading edge of plate  46  forces such coal to be advanced out of hopper  20  onto a grate (not shown). 
     As with the arrangement shown in  FIGS. 1-7 , the amount of coal falling in front of plate  46  is dependant on the rearward travel distance of plate  46 , which is determined by the point at which hand adjusted screw  66  sets against the adjustable stop  57 . End section  38  of rectangular bracket  35  has a drilled hole (not shown) at a central location, and a welded nut  65  is provided on the outer surface of end section  38  of bracket  35  surrounding such hole, with the hole having a slightly bigger diameter than the diameter of welded nut  65  and aligned as such to allow adjustment screw  66  to be secured on the threads of nut  65  and travel freely through end section  38 . Alternatively, as will be evident to those skilled in the art, the drilled hole may be threaded to receive screw  66 . When adjustment screw  66  is set inward (closer) to adjustable stop  57 , the time duration along with initial contact distance between bearing  40  and adjustable stop  57  with adjustment screw  66  is shortened, therefore causing plate  46  to travel backward a longer distance, and allowing more coal to drop from hopper  20  ahead of plate  46 . 
     As will be evident in  FIG. 9 , as the rotatable arm  31  rotates in either a clockwise or counterclockwise direction, it will at one point in its travel press against the outer surface of perpendicular plate  50 , forcing the plate  46  toward the grate and in turn pushing coal into the fire. In addition, as best shown in  FIG. 10 , at another point when the arm  31  presses on the stop  57  it will be forced against the head of adjustment screw  66  which is manually adjustable to determine the distance to which the plate  46  will be pushed back and determines the stroke of plate  46  on the feeding stroke. 
     As illustrated in  FIGS. 11-13 , the present inventor has now made several modifications to the just described system so that a solenoid arrangement such as shown in  FIGS. 3 ,  4  and  5  may be used to block movement of the adjustable stop  57  (see  FIG. 11 ) further toward the member  38  in which the adjustment set screw is mounted, thus causing return movement of the plate  46  to occur sooner and continue for a longer period, with the result being the feeding of more coal to the furnace upon the activation of the solenoid. Without such modifications, the outcome would not be very satisfactory due to imbalance. Such modifications will now be described. 
     In order to effect the use of a simple solenoid to make extra adjustments in the feeder plate adjustment, the present inventor has added a further outer section to the bracket arrangement shown in  FIGS. 8-10 . This is best illustrated in  FIG. 11 , which shows extended side sections  33  and  36  extending outwardly and supporting an outer crossbar  39  having an inwardly facing side “a” and an outwardly facing side “b”, and having an aperture  52   a  (see  FIGS. 11 and 12 ) in which a connecting rod  118  is slidably mounted. As will be shown, rod  118  forms an adjustment means for the bar  57  also having an inwardly facing side “a” and an outwardly facing surface “b”, against which side “a” the bearing or wheel  40  presses to urge the plate  46  to move outwardly. An adjustable setting nut  59  is provided on the threads of rod  118  between member  38  and outer crossbar  39  which can be moved to various points on the rod  118  to adjust where the rod  118  will be stopped from further outward movement by contact with cross member  39 , which in turn will determine how much force will be applied to the stop  57  to pull back the plate  46 . Bar  57  is welded to connecting rod  118  at point “c” (see  FIG. 11 ) at a perpendicular angle, and about a third length inwardly from side surface  36  of the bracket. Section  38  is wide enough to allow a drilled hole to act as a guide for the travel of connecting rod  118 . Bar  57  is free to slide back and forth along the outer surfaces of pair of shoulder bolts  64 . Guide hole  52  of section  38  is in alignment with aperture  52   a  in outer section  39 , and the position (point “c”) rod  118  is connected to bar  57 . A coil spring  61  about the rod  118  between stop  57  and member  38  will tend to press the stop  57  away from member  38  when no force from the rotating arm  31  and bearing or roller  40  is applied to it. When the rod  118  is pressed outwardly, the position of the set nut or stop  59  will determine where the movement will stop or the extent of such movement. This is analogous therefore to the use of the set screw  66  in the earlier drawing figures. 
     If it is desired to stop the outward movement of the stop  57  earlier, therefore, solenoid  84  which is mounted to the inner surface of cross member  39  as shown in  FIG. 11-13  can be used to move the solenoid arm  72  behind the stop  59  before it reaches the cross member  39 , which will result in the rotary movement of arm  31  drawing the plate  46  back sooner and attaining a wider feeding range. The rod  118  is positioned eccentrically with respect to the crosswise dimensions of the construction as shown so that the slide rod  118  will be approximately at the contact point of the rotating member with the face of the stop  57 . This position is shown in the drawings for a counterclockwise movement of the rotating member. The position would be reversed for a clockwise rotating member. While solenoid  84  is inactive, the weight of plunger  88 , combined with counterweight section  82 , drops down and causing section  72  of lever to lift up to a position clear of threaded adjustment nut  59 . Initial pressure from side “a” of part  57 , caused by bearing  40  will force part  57  toward end stop  63 , consequently moving connecting rod  118 , and threaded adjustment nut  59  toward side “a” of section  39 , while compressing spring  61 . Movement of section  57  connecting rod  118  through the guide hole of section  38  aperture  52 , will stop once section  57  reaches endstop  63 , or adjustment nut  59  reaches side “a” of section  39 . Any further pressure on side “a” of section  57  will cause the entire assembly to move in the rearward direction. 
     By the use of the present inventor&#39;s development a simple automatic control within limits can be provided to a single normally manually adjustable coal stoking mechanism which allows simple and particular timed adjustments in heat attained to be made. It is further noted that in contrast to prior art coal stoker automatic adjustment arrangements with the present inventor&#39;s arrangement the coal stoker motor continues to run while the stroke length adjustment is made automatically. The inventor&#39;s control system can be easily adapted for use with other systems wherein it is desired to automatically alter at least temporarily the stroke length of an apparatus moving in a reciprocating motion. 
     While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention.